1 @chapter Filtering Introduction
2 @c man begin FILTERING INTRODUCTION
4 Filtering in FFmpeg is enabled through the libavfilter library.
6 In libavfilter, a filter can have multiple inputs and multiple
8 To illustrate the sorts of things that are possible, we consider the
13 input --> split ---------------------> overlay --> output
16 +-----> crop --> vflip -------+
19 This filtergraph splits the input stream in two streams, then sends one
20 stream through the crop filter and the vflip filter, before merging it
21 back with the other stream by overlaying it on top. You can use the
22 following command to achieve this:
25 ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
28 The result will be that the top half of the video is mirrored
29 onto the bottom half of the output video.
31 Filters in the same linear chain are separated by commas, and distinct
32 linear chains of filters are separated by semicolons. In our example,
33 @var{crop,vflip} are in one linear chain, @var{split} and
34 @var{overlay} are separately in another. The points where the linear
35 chains join are labelled by names enclosed in square brackets. In the
36 example, the split filter generates two outputs that are associated to
37 the labels @var{[main]} and @var{[tmp]}.
39 The stream sent to the second output of @var{split}, labelled as
40 @var{[tmp]}, is processed through the @var{crop} filter, which crops
41 away the lower half part of the video, and then vertically flipped. The
42 @var{overlay} filter takes in input the first unchanged output of the
43 split filter (which was labelled as @var{[main]}), and overlay on its
44 lower half the output generated by the @var{crop,vflip} filterchain.
46 Some filters take in input a list of parameters: they are specified
47 after the filter name and an equal sign, and are separated from each other
50 There exist so-called @var{source filters} that do not have an
51 audio/video input, and @var{sink filters} that will not have audio/video
54 @c man end FILTERING INTRODUCTION
57 @c man begin GRAPH2DOT
59 The @file{graph2dot} program included in the FFmpeg @file{tools}
60 directory can be used to parse a filtergraph description and issue a
61 corresponding textual representation in the dot language.
68 to see how to use @file{graph2dot}.
70 You can then pass the dot description to the @file{dot} program (from
71 the graphviz suite of programs) and obtain a graphical representation
74 For example the sequence of commands:
76 echo @var{GRAPH_DESCRIPTION} | \
77 tools/graph2dot -o graph.tmp && \
78 dot -Tpng graph.tmp -o graph.png && \
82 can be used to create and display an image representing the graph
83 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
84 a complete self-contained graph, with its inputs and outputs explicitly defined.
85 For example if your command line is of the form:
87 ffmpeg -i infile -vf scale=640:360 outfile
89 your @var{GRAPH_DESCRIPTION} string will need to be of the form:
91 nullsrc,scale=640:360,nullsink
93 you may also need to set the @var{nullsrc} parameters and add a @var{format}
94 filter in order to simulate a specific input file.
98 @chapter Filtergraph description
99 @c man begin FILTERGRAPH DESCRIPTION
101 A filtergraph is a directed graph of connected filters. It can contain
102 cycles, and there can be multiple links between a pair of
103 filters. Each link has one input pad on one side connecting it to one
104 filter from which it takes its input, and one output pad on the other
105 side connecting it to one filter accepting its output.
107 Each filter in a filtergraph is an instance of a filter class
108 registered in the application, which defines the features and the
109 number of input and output pads of the filter.
111 A filter with no input pads is called a "source", and a filter with no
112 output pads is called a "sink".
114 @anchor{Filtergraph syntax}
115 @section Filtergraph syntax
117 A filtergraph has a textual representation, which is recognized by the
118 @option{-filter}/@option{-vf}/@option{-af} and
119 @option{-filter_complex} options in @command{ffmpeg} and
120 @option{-vf}/@option{-af} in @command{ffplay}, and by the
121 @code{avfilter_graph_parse_ptr()} function defined in
122 @file{libavfilter/avfilter.h}.
124 A filterchain consists of a sequence of connected filters, each one
125 connected to the previous one in the sequence. A filterchain is
126 represented by a list of ","-separated filter descriptions.
128 A filtergraph consists of a sequence of filterchains. A sequence of
129 filterchains is represented by a list of ";"-separated filterchain
132 A filter is represented by a string of the form:
133 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
135 @var{filter_name} is the name of the filter class of which the
136 described filter is an instance of, and has to be the name of one of
137 the filter classes registered in the program.
138 The name of the filter class is optionally followed by a string
141 @var{arguments} is a string which contains the parameters used to
142 initialize the filter instance. It may have one of two forms:
146 A ':'-separated list of @var{key=value} pairs.
149 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
150 the option names in the order they are declared. E.g. the @code{fade} filter
151 declares three options in this order -- @option{type}, @option{start_frame} and
152 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
153 @var{in} is assigned to the option @option{type}, @var{0} to
154 @option{start_frame} and @var{30} to @option{nb_frames}.
157 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
158 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
159 follow the same constraints order of the previous point. The following
160 @var{key=value} pairs can be set in any preferred order.
164 If the option value itself is a list of items (e.g. the @code{format} filter
165 takes a list of pixel formats), the items in the list are usually separated by
168 The list of arguments can be quoted using the character @samp{'} as initial
169 and ending mark, and the character @samp{\} for escaping the characters
170 within the quoted text; otherwise the argument string is considered
171 terminated when the next special character (belonging to the set
172 @samp{[]=;,}) is encountered.
174 The name and arguments of the filter are optionally preceded and
175 followed by a list of link labels.
176 A link label allows one to name a link and associate it to a filter output
177 or input pad. The preceding labels @var{in_link_1}
178 ... @var{in_link_N}, are associated to the filter input pads,
179 the following labels @var{out_link_1} ... @var{out_link_M}, are
180 associated to the output pads.
182 When two link labels with the same name are found in the
183 filtergraph, a link between the corresponding input and output pad is
186 If an output pad is not labelled, it is linked by default to the first
187 unlabelled input pad of the next filter in the filterchain.
188 For example in the filterchain
190 nullsrc, split[L1], [L2]overlay, nullsink
192 the split filter instance has two output pads, and the overlay filter
193 instance two input pads. The first output pad of split is labelled
194 "L1", the first input pad of overlay is labelled "L2", and the second
195 output pad of split is linked to the second input pad of overlay,
196 which are both unlabelled.
198 In a filter description, if the input label of the first filter is not
199 specified, "in" is assumed; if the output label of the last filter is not
200 specified, "out" is assumed.
202 In a complete filterchain all the unlabelled filter input and output
203 pads must be connected. A filtergraph is considered valid if all the
204 filter input and output pads of all the filterchains are connected.
206 Libavfilter will automatically insert @ref{scale} filters where format
207 conversion is required. It is possible to specify swscale flags
208 for those automatically inserted scalers by prepending
209 @code{sws_flags=@var{flags};}
210 to the filtergraph description.
212 Here is a BNF description of the filtergraph syntax:
214 @var{NAME} ::= sequence of alphanumeric characters and '_'
215 @var{LINKLABEL} ::= "[" @var{NAME} "]"
216 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
217 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
218 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
219 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
220 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
223 @section Notes on filtergraph escaping
225 Filtergraph description composition entails several levels of
226 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
227 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
228 information about the employed escaping procedure.
230 A first level escaping affects the content of each filter option
231 value, which may contain the special character @code{:} used to
232 separate values, or one of the escaping characters @code{\'}.
234 A second level escaping affects the whole filter description, which
235 may contain the escaping characters @code{\'} or the special
236 characters @code{[],;} used by the filtergraph description.
238 Finally, when you specify a filtergraph on a shell commandline, you
239 need to perform a third level escaping for the shell special
240 characters contained within it.
242 For example, consider the following string to be embedded in
243 the @ref{drawtext} filter description @option{text} value:
245 this is a 'string': may contain one, or more, special characters
248 This string contains the @code{'} special escaping character, and the
249 @code{:} special character, so it needs to be escaped in this way:
251 text=this is a \'string\'\: may contain one, or more, special characters
254 A second level of escaping is required when embedding the filter
255 description in a filtergraph description, in order to escape all the
256 filtergraph special characters. Thus the example above becomes:
258 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
260 (note that in addition to the @code{\'} escaping special characters,
261 also @code{,} needs to be escaped).
263 Finally an additional level of escaping is needed when writing the
264 filtergraph description in a shell command, which depends on the
265 escaping rules of the adopted shell. For example, assuming that
266 @code{\} is special and needs to be escaped with another @code{\}, the
267 previous string will finally result in:
269 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
272 @chapter Timeline editing
274 Some filters support a generic @option{enable} option. For the filters
275 supporting timeline editing, this option can be set to an expression which is
276 evaluated before sending a frame to the filter. If the evaluation is non-zero,
277 the filter will be enabled, otherwise the frame will be sent unchanged to the
278 next filter in the filtergraph.
280 The expression accepts the following values:
283 timestamp expressed in seconds, NAN if the input timestamp is unknown
286 sequential number of the input frame, starting from 0
289 the position in the file of the input frame, NAN if unknown
293 width and height of the input frame if video
296 Additionally, these filters support an @option{enable} command that can be used
297 to re-define the expression.
299 Like any other filtering option, the @option{enable} option follows the same
302 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
303 minutes, and a @ref{curves} filter starting at 3 seconds:
305 smartblur = enable='between(t,10,3*60)',
306 curves = enable='gte(t,3)' : preset=cross_process
309 @c man end FILTERGRAPH DESCRIPTION
311 @chapter Audio Filters
312 @c man begin AUDIO FILTERS
314 When you configure your FFmpeg build, you can disable any of the
315 existing filters using @code{--disable-filters}.
316 The configure output will show the audio filters included in your
319 Below is a description of the currently available audio filters.
323 A compressor is mainly used to reduce the dynamic range of a signal.
324 Especially modern music is mostly compressed at a high ratio to
325 improve the overall loudness. It's done to get the highest attention
326 of a listener, "fatten" the sound and bring more "power" to the track.
327 If a signal is compressed too much it may sound dull or "dead"
328 afterwards or it may start to "pump" (which could be a powerful effect
329 but can also destroy a track completely).
330 The right compression is the key to reach a professional sound and is
331 the high art of mixing and mastering. Because of its complex settings
332 it may take a long time to get the right feeling for this kind of effect.
334 Compression is done by detecting the volume above a chosen level
335 @code{threshold} and dividing it by the factor set with @code{ratio}.
336 So if you set the threshold to -12dB and your signal reaches -6dB a ratio
337 of 2:1 will result in a signal at -9dB. Because an exact manipulation of
338 the signal would cause distortion of the waveform the reduction can be
339 levelled over the time. This is done by setting "Attack" and "Release".
340 @code{attack} determines how long the signal has to rise above the threshold
341 before any reduction will occur and @code{release} sets the time the signal
342 has to fall below the threshold to reduce the reduction again. Shorter signals
343 than the chosen attack time will be left untouched.
344 The overall reduction of the signal can be made up afterwards with the
345 @code{makeup} setting. So compressing the peaks of a signal about 6dB and
346 raising the makeup to this level results in a signal twice as loud than the
347 source. To gain a softer entry in the compression the @code{knee} flattens the
348 hard edge at the threshold in the range of the chosen decibels.
350 The filter accepts the following options:
354 Set input gain. Default is 1. Range is between 0.015625 and 64.
357 If a signal of second stream rises above this level it will affect the gain
358 reduction of the first stream.
359 By default it is 0.125. Range is between 0.00097563 and 1.
362 Set a ratio by which the signal is reduced. 1:2 means that if the level
363 rose 4dB above the threshold, it will be only 2dB above after the reduction.
364 Default is 2. Range is between 1 and 20.
367 Amount of milliseconds the signal has to rise above the threshold before gain
368 reduction starts. Default is 20. Range is between 0.01 and 2000.
371 Amount of milliseconds the signal has to fall below the threshold before
372 reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
375 Set the amount by how much signal will be amplified after processing.
376 Default is 2. Range is from 1 and 64.
379 Curve the sharp knee around the threshold to enter gain reduction more softly.
380 Default is 2.82843. Range is between 1 and 8.
383 Choose if the @code{average} level between all channels of input stream
384 or the louder(@code{maximum}) channel of input stream affects the
385 reduction. Default is @code{average}.
388 Should the exact signal be taken in case of @code{peak} or an RMS one in case
389 of @code{rms}. Default is @code{rms} which is mostly smoother.
392 How much to use compressed signal in output. Default is 1.
393 Range is between 0 and 1.
398 Apply cross fade from one input audio stream to another input audio stream.
399 The cross fade is applied for specified duration near the end of first stream.
401 The filter accepts the following options:
405 Specify the number of samples for which the cross fade effect has to last.
406 At the end of the cross fade effect the first input audio will be completely
407 silent. Default is 44100.
410 Specify the duration of the cross fade effect. See
411 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
412 for the accepted syntax.
413 By default the duration is determined by @var{nb_samples}.
414 If set this option is used instead of @var{nb_samples}.
417 Should first stream end overlap with second stream start. Default is enabled.
420 Set curve for cross fade transition for first stream.
423 Set curve for cross fade transition for second stream.
425 For description of available curve types see @ref{afade} filter description.
432 Cross fade from one input to another:
434 ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:c1=exp:c2=exp output.flac
438 Cross fade from one input to another but without overlapping:
440 ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:o=0:c1=exp:c2=exp output.flac
446 Delay one or more audio channels.
448 Samples in delayed channel are filled with silence.
450 The filter accepts the following option:
454 Set list of delays in milliseconds for each channel separated by '|'.
455 At least one delay greater than 0 should be provided.
456 Unused delays will be silently ignored. If number of given delays is
457 smaller than number of channels all remaining channels will not be delayed.
464 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
465 the second channel (and any other channels that may be present) unchanged.
473 Apply echoing to the input audio.
475 Echoes are reflected sound and can occur naturally amongst mountains
476 (and sometimes large buildings) when talking or shouting; digital echo
477 effects emulate this behaviour and are often used to help fill out the
478 sound of a single instrument or vocal. The time difference between the
479 original signal and the reflection is the @code{delay}, and the
480 loudness of the reflected signal is the @code{decay}.
481 Multiple echoes can have different delays and decays.
483 A description of the accepted parameters follows.
487 Set input gain of reflected signal. Default is @code{0.6}.
490 Set output gain of reflected signal. Default is @code{0.3}.
493 Set list of time intervals in milliseconds between original signal and reflections
494 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
495 Default is @code{1000}.
498 Set list of loudnesses of reflected signals separated by '|'.
499 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
500 Default is @code{0.5}.
507 Make it sound as if there are twice as many instruments as are actually playing:
509 aecho=0.8:0.88:60:0.4
513 If delay is very short, then it sound like a (metallic) robot playing music:
519 A longer delay will sound like an open air concert in the mountains:
521 aecho=0.8:0.9:1000:0.3
525 Same as above but with one more mountain:
527 aecho=0.8:0.9:1000|1800:0.3|0.25
532 Audio emphasis filter creates or restores material directly taken from LPs or
533 emphased CDs with different filter curves. E.g. to store music on vinyl the
534 signal has to be altered by a filter first to even out the disadvantages of
535 this recording medium.
536 Once the material is played back the inverse filter has to be applied to
537 restore the distortion of the frequency response.
539 The filter accepts the following options:
549 Set filter mode. For restoring material use @code{reproduction} mode, otherwise
550 use @code{production} mode. Default is @code{reproduction} mode.
553 Set filter type. Selects medium. Can be one of the following:
565 select Compact Disc (CD).
571 select 50µs (FM-KF).
573 select 75µs (FM-KF).
579 Modify an audio signal according to the specified expressions.
581 This filter accepts one or more expressions (one for each channel),
582 which are evaluated and used to modify a corresponding audio signal.
584 It accepts the following parameters:
588 Set the '|'-separated expressions list for each separate channel. If
589 the number of input channels is greater than the number of
590 expressions, the last specified expression is used for the remaining
593 @item channel_layout, c
594 Set output channel layout. If not specified, the channel layout is
595 specified by the number of expressions. If set to @samp{same}, it will
596 use by default the same input channel layout.
599 Each expression in @var{exprs} can contain the following constants and functions:
603 channel number of the current expression
606 number of the evaluated sample, starting from 0
612 time of the evaluated sample expressed in seconds
615 @item nb_out_channels
616 input and output number of channels
619 the value of input channel with number @var{CH}
622 Note: this filter is slow. For faster processing you should use a
631 aeval=val(ch)/2:c=same
635 Invert phase of the second channel:
644 Apply fade-in/out effect to input audio.
646 A description of the accepted parameters follows.
650 Specify the effect type, can be either @code{in} for fade-in, or
651 @code{out} for a fade-out effect. Default is @code{in}.
653 @item start_sample, ss
654 Specify the number of the start sample for starting to apply the fade
655 effect. Default is 0.
658 Specify the number of samples for which the fade effect has to last. At
659 the end of the fade-in effect the output audio will have the same
660 volume as the input audio, at the end of the fade-out transition
661 the output audio will be silence. Default is 44100.
664 Specify the start time of the fade effect. Default is 0.
665 The value must be specified as a time duration; see
666 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
667 for the accepted syntax.
668 If set this option is used instead of @var{start_sample}.
671 Specify the duration of the fade effect. See
672 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
673 for the accepted syntax.
674 At the end of the fade-in effect the output audio will have the same
675 volume as the input audio, at the end of the fade-out transition
676 the output audio will be silence.
677 By default the duration is determined by @var{nb_samples}.
678 If set this option is used instead of @var{nb_samples}.
681 Set curve for fade transition.
683 It accepts the following values:
686 select triangular, linear slope (default)
688 select quarter of sine wave
690 select half of sine wave
692 select exponential sine wave
696 select inverted parabola
710 select inverted quarter of sine wave
712 select inverted half of sine wave
714 select double-exponential seat
716 select double-exponential sigmoid
724 Fade in first 15 seconds of audio:
730 Fade out last 25 seconds of a 900 seconds audio:
732 afade=t=out:st=875:d=25
737 Apply arbitrary expressions to samples in frequency domain.
741 Set frequency domain real expression for each separate channel separated
742 by '|'. Default is "1".
743 If the number of input channels is greater than the number of
744 expressions, the last specified expression is used for the remaining
748 Set frequency domain imaginary expression for each separate channel
749 separated by '|'. If not set, @var{real} option is used.
751 Each expression in @var{real} and @var{imag} can contain the following
759 current frequency bin number
762 number of available bins
765 channel number of the current expression
777 It accepts the following values:
793 Default is @code{w4096}
796 Set window function. Default is @code{hann}.
799 Set window overlap. If set to 1, the recommended overlap for selected
800 window function will be picked. Default is @code{0.75}.
807 Leave almost only low frequencies in audio:
809 afftfilt="1-clip((b/nb)*b,0,1)"
816 Set output format constraints for the input audio. The framework will
817 negotiate the most appropriate format to minimize conversions.
819 It accepts the following parameters:
823 A '|'-separated list of requested sample formats.
826 A '|'-separated list of requested sample rates.
828 @item channel_layouts
829 A '|'-separated list of requested channel layouts.
831 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
832 for the required syntax.
835 If a parameter is omitted, all values are allowed.
837 Force the output to either unsigned 8-bit or signed 16-bit stereo
839 aformat=sample_fmts=u8|s16:channel_layouts=stereo
844 A gate is mainly used to reduce lower parts of a signal. This kind of signal
845 processing reduces disturbing noise between useful signals.
847 Gating is done by detecting the volume below a chosen level @var{threshold}
848 and divide it by the factor set with @var{ratio}. The bottom of the noise
849 floor is set via @var{range}. Because an exact manipulation of the signal
850 would cause distortion of the waveform the reduction can be levelled over
851 time. This is done by setting @var{attack} and @var{release}.
853 @var{attack} determines how long the signal has to fall below the threshold
854 before any reduction will occur and @var{release} sets the time the signal
855 has to raise above the threshold to reduce the reduction again.
856 Shorter signals than the chosen attack time will be left untouched.
860 Set input level before filtering.
861 Default is 1. Allowed range is from 0.015625 to 64.
864 Set the level of gain reduction when the signal is below the threshold.
865 Default is 0.06125. Allowed range is from 0 to 1.
868 If a signal rises above this level the gain reduction is released.
869 Default is 0.125. Allowed range is from 0 to 1.
872 Set a ratio about which the signal is reduced.
873 Default is 2. Allowed range is from 1 to 9000.
876 Amount of milliseconds the signal has to rise above the threshold before gain
878 Default is 20 milliseconds. Allowed range is from 0.01 to 9000.
881 Amount of milliseconds the signal has to fall below the threshold before the
882 reduction is increased again. Default is 250 milliseconds.
883 Allowed range is from 0.01 to 9000.
886 Set amount of amplification of signal after processing.
887 Default is 1. Allowed range is from 1 to 64.
890 Curve the sharp knee around the threshold to enter gain reduction more softly.
891 Default is 2.828427125. Allowed range is from 1 to 8.
894 Choose if exact signal should be taken for detection or an RMS like one.
895 Default is rms. Can be peak or rms.
898 Choose if the average level between all channels or the louder channel affects
900 Default is average. Can be average or maximum.
905 The limiter prevents input signal from raising over a desired threshold.
906 This limiter uses lookahead technology to prevent your signal from distorting.
907 It means that there is a small delay after signal is processed. Keep in mind
908 that the delay it produces is the attack time you set.
910 The filter accepts the following options:
914 Set input gain. Default is 1.
917 Set output gain. Default is 1.
920 Don't let signals above this level pass the limiter. Default is 1.
923 The limiter will reach its attenuation level in this amount of time in
924 milliseconds. Default is 5 milliseconds.
927 Come back from limiting to attenuation 1.0 in this amount of milliseconds.
928 Default is 50 milliseconds.
931 When gain reduction is always needed ASC takes care of releasing to an
932 average reduction level rather than reaching a reduction of 0 in the release
936 Select how much the release time is affected by ASC, 0 means nearly no changes
937 in release time while 1 produces higher release times.
940 Auto level output signal. Default is enabled.
941 This normalizes audio back to 0dB if enabled.
944 Depending on picked setting it is recommended to upsample input 2x or 4x times
945 with @ref{aresample} before applying this filter.
949 Apply a two-pole all-pass filter with central frequency (in Hz)
950 @var{frequency}, and filter-width @var{width}.
951 An all-pass filter changes the audio's frequency to phase relationship
952 without changing its frequency to amplitude relationship.
954 The filter accepts the following options:
961 Set method to specify band-width of filter.
974 Specify the band-width of a filter in width_type units.
980 Merge two or more audio streams into a single multi-channel stream.
982 The filter accepts the following options:
987 Set the number of inputs. Default is 2.
991 If the channel layouts of the inputs are disjoint, and therefore compatible,
992 the channel layout of the output will be set accordingly and the channels
993 will be reordered as necessary. If the channel layouts of the inputs are not
994 disjoint, the output will have all the channels of the first input then all
995 the channels of the second input, in that order, and the channel layout of
996 the output will be the default value corresponding to the total number of
999 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
1000 is FC+BL+BR, then the output will be in 5.1, with the channels in the
1001 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
1002 first input, b1 is the first channel of the second input).
1004 On the other hand, if both input are in stereo, the output channels will be
1005 in the default order: a1, a2, b1, b2, and the channel layout will be
1006 arbitrarily set to 4.0, which may or may not be the expected value.
1008 All inputs must have the same sample rate, and format.
1010 If inputs do not have the same duration, the output will stop with the
1013 @subsection Examples
1017 Merge two mono files into a stereo stream:
1019 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
1023 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
1025 ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv
1031 Mixes multiple audio inputs into a single output.
1033 Note that this filter only supports float samples (the @var{amerge}
1034 and @var{pan} audio filters support many formats). If the @var{amix}
1035 input has integer samples then @ref{aresample} will be automatically
1036 inserted to perform the conversion to float samples.
1040 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
1042 will mix 3 input audio streams to a single output with the same duration as the
1043 first input and a dropout transition time of 3 seconds.
1045 It accepts the following parameters:
1049 The number of inputs. If unspecified, it defaults to 2.
1052 How to determine the end-of-stream.
1056 The duration of the longest input. (default)
1059 The duration of the shortest input.
1062 The duration of the first input.
1066 @item dropout_transition
1067 The transition time, in seconds, for volume renormalization when an input
1068 stream ends. The default value is 2 seconds.
1072 @section anequalizer
1074 High-order parametric multiband equalizer for each channel.
1076 It accepts the following parameters:
1080 This option string is in format:
1081 "c@var{chn} f=@var{cf} w=@var{w} g=@var{g} t=@var{f} | ..."
1082 Each equalizer band is separated by '|'.
1086 Set channel number to which equalization will be applied.
1087 If input doesn't have that channel the entry is ignored.
1090 Set central frequency for band.
1091 If input doesn't have that frequency the entry is ignored.
1094 Set band width in hertz.
1097 Set band gain in dB.
1100 Set filter type for band, optional, can be:
1104 Butterworth, this is default.
1115 With this option activated frequency response of anequalizer is displayed
1119 Set video stream size. Only useful if curves option is activated.
1122 Set max gain that will be displayed. Only useful if curves option is activated.
1123 Setting this to reasonable value allows to display gain which is derived from
1124 neighbour bands which are too close to each other and thus produce higher gain
1125 when both are activated.
1128 Set frequency scale used to draw frequency response in video output.
1129 Can be linear or logarithmic. Default is logarithmic.
1132 Set color for each channel curve which is going to be displayed in video stream.
1133 This is list of color names separated by space or by '|'.
1134 Unrecognised or missing colors will be replaced by white color.
1137 @subsection Examples
1141 Lower gain by 10 of central frequency 200Hz and width 100 Hz
1142 for first 2 channels using Chebyshev type 1 filter:
1144 anequalizer=c0 f=200 w=100 g=-10 t=1|c1 f=200 w=100 g=-10 t=1
1148 @subsection Commands
1150 This filter supports the following commands:
1153 Alter existing filter parameters.
1154 Syntax for the commands is : "@var{fN}|f=@var{freq}|w=@var{width}|g=@var{gain}"
1156 @var{fN} is existing filter number, starting from 0, if no such filter is available
1158 @var{freq} set new frequency parameter.
1159 @var{width} set new width parameter in herz.
1160 @var{gain} set new gain parameter in dB.
1162 Full filter invocation with asendcmd may look like this:
1163 asendcmd=c='4.0 anequalizer change 0|f=200|w=50|g=1',anequalizer=...
1168 Pass the audio source unchanged to the output.
1172 Pad the end of an audio stream with silence.
1174 This can be used together with @command{ffmpeg} @option{-shortest} to
1175 extend audio streams to the same length as the video stream.
1177 A description of the accepted options follows.
1181 Set silence packet size. Default value is 4096.
1184 Set the number of samples of silence to add to the end. After the
1185 value is reached, the stream is terminated. This option is mutually
1186 exclusive with @option{whole_len}.
1189 Set the minimum total number of samples in the output audio stream. If
1190 the value is longer than the input audio length, silence is added to
1191 the end, until the value is reached. This option is mutually exclusive
1192 with @option{pad_len}.
1195 If neither the @option{pad_len} nor the @option{whole_len} option is
1196 set, the filter will add silence to the end of the input stream
1199 @subsection Examples
1203 Add 1024 samples of silence to the end of the input:
1209 Make sure the audio output will contain at least 10000 samples, pad
1210 the input with silence if required:
1212 apad=whole_len=10000
1216 Use @command{ffmpeg} to pad the audio input with silence, so that the
1217 video stream will always result the shortest and will be converted
1218 until the end in the output file when using the @option{shortest}
1221 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
1226 Add a phasing effect to the input audio.
1228 A phaser filter creates series of peaks and troughs in the frequency spectrum.
1229 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
1231 A description of the accepted parameters follows.
1235 Set input gain. Default is 0.4.
1238 Set output gain. Default is 0.74
1241 Set delay in milliseconds. Default is 3.0.
1244 Set decay. Default is 0.4.
1247 Set modulation speed in Hz. Default is 0.5.
1250 Set modulation type. Default is triangular.
1252 It accepts the following values:
1261 Audio pulsator is something between an autopanner and a tremolo.
1262 But it can produce funny stereo effects as well. Pulsator changes the volume
1263 of the left and right channel based on a LFO (low frequency oscillator) with
1264 different waveforms and shifted phases.
1265 This filter have the ability to define an offset between left and right
1266 channel. An offset of 0 means that both LFO shapes match each other.
1267 The left and right channel are altered equally - a conventional tremolo.
1268 An offset of 50% means that the shape of the right channel is exactly shifted
1269 in phase (or moved backwards about half of the frequency) - pulsator acts as
1270 an autopanner. At 1 both curves match again. Every setting in between moves the
1271 phase shift gapless between all stages and produces some "bypassing" sounds with
1272 sine and triangle waveforms. The more you set the offset near 1 (starting from
1273 the 0.5) the faster the signal passes from the left to the right speaker.
1275 The filter accepts the following options:
1279 Set input gain. By default it is 1. Range is [0.015625 - 64].
1282 Set output gain. By default it is 1. Range is [0.015625 - 64].
1285 Set waveform shape the LFO will use. Can be one of: sine, triangle, square,
1286 sawup or sawdown. Default is sine.
1289 Set modulation. Define how much of original signal is affected by the LFO.
1292 Set left channel offset. Default is 0. Allowed range is [0 - 1].
1295 Set right channel offset. Default is 0.5. Allowed range is [0 - 1].
1298 Set pulse width. Default is 1. Allowed range is [0 - 2].
1301 Set possible timing mode. Can be one of: bpm, ms or hz. Default is hz.
1304 Set bpm. Default is 120. Allowed range is [30 - 300]. Only used if timing
1308 Set ms. Default is 500. Allowed range is [10 - 2000]. Only used if timing
1312 Set frequency in Hz. Default is 2. Allowed range is [0.01 - 100]. Only used
1313 if timing is set to hz.
1319 Resample the input audio to the specified parameters, using the
1320 libswresample library. If none are specified then the filter will
1321 automatically convert between its input and output.
1323 This filter is also able to stretch/squeeze the audio data to make it match
1324 the timestamps or to inject silence / cut out audio to make it match the
1325 timestamps, do a combination of both or do neither.
1327 The filter accepts the syntax
1328 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
1329 expresses a sample rate and @var{resampler_options} is a list of
1330 @var{key}=@var{value} pairs, separated by ":". See the
1331 ffmpeg-resampler manual for the complete list of supported options.
1333 @subsection Examples
1337 Resample the input audio to 44100Hz:
1343 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
1344 samples per second compensation:
1346 aresample=async=1000
1350 @section asetnsamples
1352 Set the number of samples per each output audio frame.
1354 The last output packet may contain a different number of samples, as
1355 the filter will flush all the remaining samples when the input audio
1358 The filter accepts the following options:
1362 @item nb_out_samples, n
1363 Set the number of frames per each output audio frame. The number is
1364 intended as the number of samples @emph{per each channel}.
1365 Default value is 1024.
1368 If set to 1, the filter will pad the last audio frame with zeroes, so
1369 that the last frame will contain the same number of samples as the
1370 previous ones. Default value is 1.
1373 For example, to set the number of per-frame samples to 1234 and
1374 disable padding for the last frame, use:
1376 asetnsamples=n=1234:p=0
1381 Set the sample rate without altering the PCM data.
1382 This will result in a change of speed and pitch.
1384 The filter accepts the following options:
1387 @item sample_rate, r
1388 Set the output sample rate. Default is 44100 Hz.
1393 Show a line containing various information for each input audio frame.
1394 The input audio is not modified.
1396 The shown line contains a sequence of key/value pairs of the form
1397 @var{key}:@var{value}.
1399 The following values are shown in the output:
1403 The (sequential) number of the input frame, starting from 0.
1406 The presentation timestamp of the input frame, in time base units; the time base
1407 depends on the filter input pad, and is usually 1/@var{sample_rate}.
1410 The presentation timestamp of the input frame in seconds.
1413 position of the frame in the input stream, -1 if this information in
1414 unavailable and/or meaningless (for example in case of synthetic audio)
1423 The sample rate for the audio frame.
1426 The number of samples (per channel) in the frame.
1429 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
1430 audio, the data is treated as if all the planes were concatenated.
1432 @item plane_checksums
1433 A list of Adler-32 checksums for each data plane.
1439 Display time domain statistical information about the audio channels.
1440 Statistics are calculated and displayed for each audio channel and,
1441 where applicable, an overall figure is also given.
1443 It accepts the following option:
1446 Short window length in seconds, used for peak and trough RMS measurement.
1447 Default is @code{0.05} (50 milliseconds). Allowed range is @code{[0.1 - 10]}.
1451 Set metadata injection. All the metadata keys are prefixed with @code{lavfi.astats.X},
1452 where @code{X} is channel number starting from 1 or string @code{Overall}. Default is
1455 Available keys for each channel are:
1486 For example full key look like this @code{lavfi.astats.1.DC_offset} or
1487 this @code{lavfi.astats.Overall.Peak_count}.
1489 For description what each key means read below.
1492 Set number of frame after which stats are going to be recalculated.
1493 Default is disabled.
1496 A description of each shown parameter follows:
1500 Mean amplitude displacement from zero.
1503 Minimal sample level.
1506 Maximal sample level.
1508 @item Min difference
1509 Minimal difference between two consecutive samples.
1511 @item Max difference
1512 Maximal difference between two consecutive samples.
1514 @item Mean difference
1515 Mean difference between two consecutive samples.
1516 The average of each difference between two consecutive samples.
1520 Standard peak and RMS level measured in dBFS.
1524 Peak and trough values for RMS level measured over a short window.
1527 Standard ratio of peak to RMS level (note: not in dB).
1530 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
1531 (i.e. either @var{Min level} or @var{Max level}).
1534 Number of occasions (not the number of samples) that the signal attained either
1535 @var{Min level} or @var{Max level}.
1538 Overall bit depth of audio. Number of bits used for each sample.
1543 Synchronize audio data with timestamps by squeezing/stretching it and/or
1544 dropping samples/adding silence when needed.
1546 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1548 It accepts the following parameters:
1552 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1553 by default. When disabled, time gaps are covered with silence.
1556 The minimum difference between timestamps and audio data (in seconds) to trigger
1557 adding/dropping samples. The default value is 0.1. If you get an imperfect
1558 sync with this filter, try setting this parameter to 0.
1561 The maximum compensation in samples per second. Only relevant with compensate=1.
1562 The default value is 500.
1565 Assume that the first PTS should be this value. The time base is 1 / sample
1566 rate. This allows for padding/trimming at the start of the stream. By default,
1567 no assumption is made about the first frame's expected PTS, so no padding or
1568 trimming is done. For example, this could be set to 0 to pad the beginning with
1569 silence if an audio stream starts after the video stream or to trim any samples
1570 with a negative PTS due to encoder delay.
1578 The filter accepts exactly one parameter, the audio tempo. If not
1579 specified then the filter will assume nominal 1.0 tempo. Tempo must
1580 be in the [0.5, 2.0] range.
1582 @subsection Examples
1586 Slow down audio to 80% tempo:
1592 To speed up audio to 125% tempo:
1600 Trim the input so that the output contains one continuous subpart of the input.
1602 It accepts the following parameters:
1605 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1606 sample with the timestamp @var{start} will be the first sample in the output.
1609 Specify time of the first audio sample that will be dropped, i.e. the
1610 audio sample immediately preceding the one with the timestamp @var{end} will be
1611 the last sample in the output.
1614 Same as @var{start}, except this option sets the start timestamp in samples
1618 Same as @var{end}, except this option sets the end timestamp in samples instead
1622 The maximum duration of the output in seconds.
1625 The number of the first sample that should be output.
1628 The number of the first sample that should be dropped.
1631 @option{start}, @option{end}, and @option{duration} are expressed as time
1632 duration specifications; see
1633 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
1635 Note that the first two sets of the start/end options and the @option{duration}
1636 option look at the frame timestamp, while the _sample options simply count the
1637 samples that pass through the filter. So start/end_pts and start/end_sample will
1638 give different results when the timestamps are wrong, inexact or do not start at
1639 zero. Also note that this filter does not modify the timestamps. If you wish
1640 to have the output timestamps start at zero, insert the asetpts filter after the
1643 If multiple start or end options are set, this filter tries to be greedy and
1644 keep all samples that match at least one of the specified constraints. To keep
1645 only the part that matches all the constraints at once, chain multiple atrim
1648 The defaults are such that all the input is kept. So it is possible to set e.g.
1649 just the end values to keep everything before the specified time.
1654 Drop everything except the second minute of input:
1656 ffmpeg -i INPUT -af atrim=60:120
1660 Keep only the first 1000 samples:
1662 ffmpeg -i INPUT -af atrim=end_sample=1000
1669 Apply a two-pole Butterworth band-pass filter with central
1670 frequency @var{frequency}, and (3dB-point) band-width width.
1671 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1672 instead of the default: constant 0dB peak gain.
1673 The filter roll off at 6dB per octave (20dB per decade).
1675 The filter accepts the following options:
1679 Set the filter's central frequency. Default is @code{3000}.
1682 Constant skirt gain if set to 1. Defaults to 0.
1685 Set method to specify band-width of filter.
1698 Specify the band-width of a filter in width_type units.
1703 Apply a two-pole Butterworth band-reject filter with central
1704 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1705 The filter roll off at 6dB per octave (20dB per decade).
1707 The filter accepts the following options:
1711 Set the filter's central frequency. Default is @code{3000}.
1714 Set method to specify band-width of filter.
1727 Specify the band-width of a filter in width_type units.
1732 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1733 shelving filter with a response similar to that of a standard
1734 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1736 The filter accepts the following options:
1740 Give the gain at 0 Hz. Its useful range is about -20
1741 (for a large cut) to +20 (for a large boost).
1742 Beware of clipping when using a positive gain.
1745 Set the filter's central frequency and so can be used
1746 to extend or reduce the frequency range to be boosted or cut.
1747 The default value is @code{100} Hz.
1750 Set method to specify band-width of filter.
1763 Determine how steep is the filter's shelf transition.
1768 Apply a biquad IIR filter with the given coefficients.
1769 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1770 are the numerator and denominator coefficients respectively.
1773 Bauer stereo to binaural transformation, which improves headphone listening of
1774 stereo audio records.
1776 It accepts the following parameters:
1780 Pre-defined crossfeed level.
1784 Default level (fcut=700, feed=50).
1787 Chu Moy circuit (fcut=700, feed=60).
1790 Jan Meier circuit (fcut=650, feed=95).
1795 Cut frequency (in Hz).
1804 Remap input channels to new locations.
1806 It accepts the following parameters:
1808 @item channel_layout
1809 The channel layout of the output stream.
1812 Map channels from input to output. The argument is a '|'-separated list of
1813 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1814 @var{in_channel} form. @var{in_channel} can be either the name of the input
1815 channel (e.g. FL for front left) or its index in the input channel layout.
1816 @var{out_channel} is the name of the output channel or its index in the output
1817 channel layout. If @var{out_channel} is not given then it is implicitly an
1818 index, starting with zero and increasing by one for each mapping.
1821 If no mapping is present, the filter will implicitly map input channels to
1822 output channels, preserving indices.
1824 For example, assuming a 5.1+downmix input MOV file,
1826 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1828 will create an output WAV file tagged as stereo from the downmix channels of
1831 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1833 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:5.1' out.wav
1836 @section channelsplit
1838 Split each channel from an input audio stream into a separate output stream.
1840 It accepts the following parameters:
1842 @item channel_layout
1843 The channel layout of the input stream. The default is "stereo".
1846 For example, assuming a stereo input MP3 file,
1848 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1850 will create an output Matroska file with two audio streams, one containing only
1851 the left channel and the other the right channel.
1853 Split a 5.1 WAV file into per-channel files:
1855 ffmpeg -i in.wav -filter_complex
1856 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1857 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1858 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1863 Add a chorus effect to the audio.
1865 Can make a single vocal sound like a chorus, but can also be applied to instrumentation.
1867 Chorus resembles an echo effect with a short delay, but whereas with echo the delay is
1868 constant, with chorus, it is varied using using sinusoidal or triangular modulation.
1869 The modulation depth defines the range the modulated delay is played before or after
1870 the delay. Hence the delayed sound will sound slower or faster, that is the delayed
1871 sound tuned around the original one, like in a chorus where some vocals are slightly
1874 It accepts the following parameters:
1877 Set input gain. Default is 0.4.
1880 Set output gain. Default is 0.4.
1883 Set delays. A typical delay is around 40ms to 60ms.
1895 @subsection Examples
1901 chorus=0.7:0.9:55:0.4:0.25:2
1907 chorus=0.6:0.9:50|60:0.4|0.32:0.25|0.4:2|1.3
1911 Fuller sounding chorus with three delays:
1913 chorus=0.5:0.9:50|60|40:0.4|0.32|0.3:0.25|0.4|0.3:2|2.3|1.3
1918 Compress or expand the audio's dynamic range.
1920 It accepts the following parameters:
1926 A list of times in seconds for each channel over which the instantaneous level
1927 of the input signal is averaged to determine its volume. @var{attacks} refers to
1928 increase of volume and @var{decays} refers to decrease of volume. For most
1929 situations, the attack time (response to the audio getting louder) should be
1930 shorter than the decay time, because the human ear is more sensitive to sudden
1931 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1932 a typical value for decay is 0.8 seconds.
1933 If specified number of attacks & decays is lower than number of channels, the last
1934 set attack/decay will be used for all remaining channels.
1937 A list of points for the transfer function, specified in dB relative to the
1938 maximum possible signal amplitude. Each key points list must be defined using
1939 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1940 @code{x0/y0 x1/y1 x2/y2 ....}
1942 The input values must be in strictly increasing order but the transfer function
1943 does not have to be monotonically rising. The point @code{0/0} is assumed but
1944 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1945 function are @code{-70/-70|-60/-20}.
1948 Set the curve radius in dB for all joints. It defaults to 0.01.
1951 Set the additional gain in dB to be applied at all points on the transfer
1952 function. This allows for easy adjustment of the overall gain.
1956 Set an initial volume, in dB, to be assumed for each channel when filtering
1957 starts. This permits the user to supply a nominal level initially, so that, for
1958 example, a very large gain is not applied to initial signal levels before the
1959 companding has begun to operate. A typical value for audio which is initially
1960 quiet is -90 dB. It defaults to 0.
1963 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1964 delayed before being fed to the volume adjuster. Specifying a delay
1965 approximately equal to the attack/decay times allows the filter to effectively
1966 operate in predictive rather than reactive mode. It defaults to 0.
1970 @subsection Examples
1974 Make music with both quiet and loud passages suitable for listening to in a
1977 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1980 Another example for audio with whisper and explosion parts:
1982 compand=0|0:1|1:-90/-900|-70/-70|-30/-9|0/-3:6:0:0:0
1986 A noise gate for when the noise is at a lower level than the signal:
1988 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1992 Here is another noise gate, this time for when the noise is at a higher level
1993 than the signal (making it, in some ways, similar to squelch):
1995 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1999 2:1 compression starting at -6dB:
2001 compand=points=-80/-80|-6/-6|0/-3.8|20/3.5
2005 2:1 compression starting at -9dB:
2007 compand=points=-80/-80|-9/-9|0/-5.3|20/2.9
2011 2:1 compression starting at -12dB:
2013 compand=points=-80/-80|-12/-12|0/-6.8|20/1.9
2017 2:1 compression starting at -18dB:
2019 compand=points=-80/-80|-18/-18|0/-9.8|20/0.7
2023 3:1 compression starting at -15dB:
2025 compand=points=-80/-80|-15/-15|0/-10.8|20/-5.2
2031 compand=points=-80/-105|-62/-80|-15.4/-15.4|0/-12|20/-7.6
2037 compand=attacks=0:points=-80/-169|-54/-80|-49.5/-64.6|-41.1/-41.1|-25.8/-15|-10.8/-4.5|0/0|20/8.3
2041 Hard limiter at -6dB:
2043 compand=attacks=0:points=-80/-80|-6/-6|20/-6
2047 Hard limiter at -12dB:
2049 compand=attacks=0:points=-80/-80|-12/-12|20/-12
2053 Hard noise gate at -35 dB:
2055 compand=attacks=0:points=-80/-115|-35.1/-80|-35/-35|20/20
2061 compand=attacks=0:points=-80/-80|-12.4/-12.4|-6/-8|0/-6.8|20/-2.8
2065 @section compensationdelay
2067 Compensation Delay Line is a metric based delay to compensate differing
2068 positions of microphones or speakers.
2070 For example, you have recorded guitar with two microphones placed in
2071 different location. Because the front of sound wave has fixed speed in
2072 normal conditions, the phasing of microphones can vary and depends on
2073 their location and interposition. The best sound mix can be achieved when
2074 these microphones are in phase (synchronized). Note that distance of
2075 ~30 cm between microphones makes one microphone to capture signal in
2076 antiphase to another microphone. That makes the final mix sounding moody.
2077 This filter helps to solve phasing problems by adding different delays
2078 to each microphone track and make them synchronized.
2080 The best result can be reached when you take one track as base and
2081 synchronize other tracks one by one with it.
2082 Remember that synchronization/delay tolerance depends on sample rate, too.
2083 Higher sample rates will give more tolerance.
2085 It accepts the following parameters:
2089 Set millimeters distance. This is compensation distance for fine tuning.
2093 Set cm distance. This is compensation distance for tightening distance setup.
2097 Set meters distance. This is compensation distance for hard distance setup.
2101 Set dry amount. Amount of unprocessed (dry) signal.
2105 Set wet amount. Amount of processed (wet) signal.
2109 Set temperature degree in Celsius. This is the temperature of the environment.
2114 Apply a DC shift to the audio.
2116 This can be useful to remove a DC offset (caused perhaps by a hardware problem
2117 in the recording chain) from the audio. The effect of a DC offset is reduced
2118 headroom and hence volume. The @ref{astats} filter can be used to determine if
2119 a signal has a DC offset.
2123 Set the DC shift, allowed range is [-1, 1]. It indicates the amount to shift
2127 Optional. It should have a value much less than 1 (e.g. 0.05 or 0.02) and is
2128 used to prevent clipping.
2132 Dynamic Audio Normalizer.
2134 This filter applies a certain amount of gain to the input audio in order
2135 to bring its peak magnitude to a target level (e.g. 0 dBFS). However, in
2136 contrast to more "simple" normalization algorithms, the Dynamic Audio
2137 Normalizer *dynamically* re-adjusts the gain factor to the input audio.
2138 This allows for applying extra gain to the "quiet" sections of the audio
2139 while avoiding distortions or clipping the "loud" sections. In other words:
2140 The Dynamic Audio Normalizer will "even out" the volume of quiet and loud
2141 sections, in the sense that the volume of each section is brought to the
2142 same target level. Note, however, that the Dynamic Audio Normalizer achieves
2143 this goal *without* applying "dynamic range compressing". It will retain 100%
2144 of the dynamic range *within* each section of the audio file.
2148 Set the frame length in milliseconds. In range from 10 to 8000 milliseconds.
2149 Default is 500 milliseconds.
2150 The Dynamic Audio Normalizer processes the input audio in small chunks,
2151 referred to as frames. This is required, because a peak magnitude has no
2152 meaning for just a single sample value. Instead, we need to determine the
2153 peak magnitude for a contiguous sequence of sample values. While a "standard"
2154 normalizer would simply use the peak magnitude of the complete file, the
2155 Dynamic Audio Normalizer determines the peak magnitude individually for each
2156 frame. The length of a frame is specified in milliseconds. By default, the
2157 Dynamic Audio Normalizer uses a frame length of 500 milliseconds, which has
2158 been found to give good results with most files.
2159 Note that the exact frame length, in number of samples, will be determined
2160 automatically, based on the sampling rate of the individual input audio file.
2163 Set the Gaussian filter window size. In range from 3 to 301, must be odd
2164 number. Default is 31.
2165 Probably the most important parameter of the Dynamic Audio Normalizer is the
2166 @code{window size} of the Gaussian smoothing filter. The filter's window size
2167 is specified in frames, centered around the current frame. For the sake of
2168 simplicity, this must be an odd number. Consequently, the default value of 31
2169 takes into account the current frame, as well as the 15 preceding frames and
2170 the 15 subsequent frames. Using a larger window results in a stronger
2171 smoothing effect and thus in less gain variation, i.e. slower gain
2172 adaptation. Conversely, using a smaller window results in a weaker smoothing
2173 effect and thus in more gain variation, i.e. faster gain adaptation.
2174 In other words, the more you increase this value, the more the Dynamic Audio
2175 Normalizer will behave like a "traditional" normalization filter. On the
2176 contrary, the more you decrease this value, the more the Dynamic Audio
2177 Normalizer will behave like a dynamic range compressor.
2180 Set the target peak value. This specifies the highest permissible magnitude
2181 level for the normalized audio input. This filter will try to approach the
2182 target peak magnitude as closely as possible, but at the same time it also
2183 makes sure that the normalized signal will never exceed the peak magnitude.
2184 A frame's maximum local gain factor is imposed directly by the target peak
2185 magnitude. The default value is 0.95 and thus leaves a headroom of 5%*.
2186 It is not recommended to go above this value.
2189 Set the maximum gain factor. In range from 1.0 to 100.0. Default is 10.0.
2190 The Dynamic Audio Normalizer determines the maximum possible (local) gain
2191 factor for each input frame, i.e. the maximum gain factor that does not
2192 result in clipping or distortion. The maximum gain factor is determined by
2193 the frame's highest magnitude sample. However, the Dynamic Audio Normalizer
2194 additionally bounds the frame's maximum gain factor by a predetermined
2195 (global) maximum gain factor. This is done in order to avoid excessive gain
2196 factors in "silent" or almost silent frames. By default, the maximum gain
2197 factor is 10.0, For most inputs the default value should be sufficient and
2198 it usually is not recommended to increase this value. Though, for input
2199 with an extremely low overall volume level, it may be necessary to allow even
2200 higher gain factors. Note, however, that the Dynamic Audio Normalizer does
2201 not simply apply a "hard" threshold (i.e. cut off values above the threshold).
2202 Instead, a "sigmoid" threshold function will be applied. This way, the
2203 gain factors will smoothly approach the threshold value, but never exceed that
2207 Set the target RMS. In range from 0.0 to 1.0. Default is 0.0 - disabled.
2208 By default, the Dynamic Audio Normalizer performs "peak" normalization.
2209 This means that the maximum local gain factor for each frame is defined
2210 (only) by the frame's highest magnitude sample. This way, the samples can
2211 be amplified as much as possible without exceeding the maximum signal
2212 level, i.e. without clipping. Optionally, however, the Dynamic Audio
2213 Normalizer can also take into account the frame's root mean square,
2214 abbreviated RMS. In electrical engineering, the RMS is commonly used to
2215 determine the power of a time-varying signal. It is therefore considered
2216 that the RMS is a better approximation of the "perceived loudness" than
2217 just looking at the signal's peak magnitude. Consequently, by adjusting all
2218 frames to a constant RMS value, a uniform "perceived loudness" can be
2219 established. If a target RMS value has been specified, a frame's local gain
2220 factor is defined as the factor that would result in exactly that RMS value.
2221 Note, however, that the maximum local gain factor is still restricted by the
2222 frame's highest magnitude sample, in order to prevent clipping.
2225 Enable channels coupling. By default is enabled.
2226 By default, the Dynamic Audio Normalizer will amplify all channels by the same
2227 amount. This means the same gain factor will be applied to all channels, i.e.
2228 the maximum possible gain factor is determined by the "loudest" channel.
2229 However, in some recordings, it may happen that the volume of the different
2230 channels is uneven, e.g. one channel may be "quieter" than the other one(s).
2231 In this case, this option can be used to disable the channel coupling. This way,
2232 the gain factor will be determined independently for each channel, depending
2233 only on the individual channel's highest magnitude sample. This allows for
2234 harmonizing the volume of the different channels.
2237 Enable DC bias correction. By default is disabled.
2238 An audio signal (in the time domain) is a sequence of sample values.
2239 In the Dynamic Audio Normalizer these sample values are represented in the
2240 -1.0 to 1.0 range, regardless of the original input format. Normally, the
2241 audio signal, or "waveform", should be centered around the zero point.
2242 That means if we calculate the mean value of all samples in a file, or in a
2243 single frame, then the result should be 0.0 or at least very close to that
2244 value. If, however, there is a significant deviation of the mean value from
2245 0.0, in either positive or negative direction, this is referred to as a
2246 DC bias or DC offset. Since a DC bias is clearly undesirable, the Dynamic
2247 Audio Normalizer provides optional DC bias correction.
2248 With DC bias correction enabled, the Dynamic Audio Normalizer will determine
2249 the mean value, or "DC correction" offset, of each input frame and subtract
2250 that value from all of the frame's sample values which ensures those samples
2251 are centered around 0.0 again. Also, in order to avoid "gaps" at the frame
2252 boundaries, the DC correction offset values will be interpolated smoothly
2253 between neighbouring frames.
2256 Enable alternative boundary mode. By default is disabled.
2257 The Dynamic Audio Normalizer takes into account a certain neighbourhood
2258 around each frame. This includes the preceding frames as well as the
2259 subsequent frames. However, for the "boundary" frames, located at the very
2260 beginning and at the very end of the audio file, not all neighbouring
2261 frames are available. In particular, for the first few frames in the audio
2262 file, the preceding frames are not known. And, similarly, for the last few
2263 frames in the audio file, the subsequent frames are not known. Thus, the
2264 question arises which gain factors should be assumed for the missing frames
2265 in the "boundary" region. The Dynamic Audio Normalizer implements two modes
2266 to deal with this situation. The default boundary mode assumes a gain factor
2267 of exactly 1.0 for the missing frames, resulting in a smooth "fade in" and
2268 "fade out" at the beginning and at the end of the input, respectively.
2271 Set the compress factor. In range from 0.0 to 30.0. Default is 0.0.
2272 By default, the Dynamic Audio Normalizer does not apply "traditional"
2273 compression. This means that signal peaks will not be pruned and thus the
2274 full dynamic range will be retained within each local neighbourhood. However,
2275 in some cases it may be desirable to combine the Dynamic Audio Normalizer's
2276 normalization algorithm with a more "traditional" compression.
2277 For this purpose, the Dynamic Audio Normalizer provides an optional compression
2278 (thresholding) function. If (and only if) the compression feature is enabled,
2279 all input frames will be processed by a soft knee thresholding function prior
2280 to the actual normalization process. Put simply, the thresholding function is
2281 going to prune all samples whose magnitude exceeds a certain threshold value.
2282 However, the Dynamic Audio Normalizer does not simply apply a fixed threshold
2283 value. Instead, the threshold value will be adjusted for each individual
2285 In general, smaller parameters result in stronger compression, and vice versa.
2286 Values below 3.0 are not recommended, because audible distortion may appear.
2291 Make audio easier to listen to on headphones.
2293 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
2294 so that when listened to on headphones the stereo image is moved from
2295 inside your head (standard for headphones) to outside and in front of
2296 the listener (standard for speakers).
2302 Apply a two-pole peaking equalisation (EQ) filter. With this
2303 filter, the signal-level at and around a selected frequency can
2304 be increased or decreased, whilst (unlike bandpass and bandreject
2305 filters) that at all other frequencies is unchanged.
2307 In order to produce complex equalisation curves, this filter can
2308 be given several times, each with a different central frequency.
2310 The filter accepts the following options:
2314 Set the filter's central frequency in Hz.
2317 Set method to specify band-width of filter.
2330 Specify the band-width of a filter in width_type units.
2333 Set the required gain or attenuation in dB.
2334 Beware of clipping when using a positive gain.
2337 @subsection Examples
2340 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
2342 equalizer=f=1000:width_type=h:width=200:g=-10
2346 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
2348 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
2352 @section extrastereo
2354 Linearly increases the difference between left and right channels which
2355 adds some sort of "live" effect to playback.
2357 The filter accepts the following option:
2361 Sets the difference coefficient (default: 2.5). 0.0 means mono sound
2362 (average of both channels), with 1.0 sound will be unchanged, with
2363 -1.0 left and right channels will be swapped.
2366 Enable clipping. By default is enabled.
2369 @section firequalizer
2370 Apply FIR Equalization using arbitrary frequency response.
2372 The filter accepts the following option:
2376 Set gain curve equation (in dB). The expression can contain variables:
2379 the evaluated frequency
2383 channel number, set to 0 when multichannels evaluation is disabled
2385 channel id, see libavutil/channel_layout.h, set to the first channel id when
2386 multichannels evaluation is disabled
2390 channel_layout, see libavutil/channel_layout.h
2395 @item gain_interpolate(f)
2396 interpolate gain on frequency f based on gain_entry
2398 This option is also available as command. Default is @code{gain_interpolate(f)}.
2401 Set gain entry for gain_interpolate function. The expression can
2405 store gain entry at frequency f with value g
2407 This option is also available as command.
2410 Set filter delay in seconds. Higher value means more accurate.
2411 Default is @code{0.01}.
2414 Set filter accuracy in Hz. Lower value means more accurate.
2415 Default is @code{5}.
2418 Set window function. Acceptable values are:
2421 rectangular window, useful when gain curve is already smooth
2423 hann window (default)
2429 3-terms continuous 1st derivative nuttall window
2431 minimum 3-terms discontinuous nuttall window
2433 4-terms continuous 1st derivative nuttall window
2435 minimum 4-terms discontinuous nuttall (blackman-nuttall) window
2437 blackman-harris window
2441 If enabled, use fixed number of audio samples. This improves speed when
2442 filtering with large delay. Default is disabled.
2445 Enable multichannels evaluation on gain. Default is disabled.
2448 Enable zero phase mode by substracting timestamp to compensate delay.
2449 Default is disabled.
2452 @subsection Examples
2457 firequalizer=gain='if(lt(f,1000), 0, -INF)'
2460 lowpass at 1000 Hz with gain_entry:
2462 firequalizer=gain_entry='entry(1000,0); entry(1001, -INF)'
2465 custom equalization:
2467 firequalizer=gain_entry='entry(100,0); entry(400, -4); entry(1000, -6); entry(2000, 0)'
2470 higher delay with zero phase to compensate delay:
2472 firequalizer=delay=0.1:fixed=on:zero_phase=on
2475 lowpass on left channel, highpass on right channel:
2477 firequalizer=gain='if(eq(chid,1), gain_interpolate(f), if(eq(chid,2), gain_interpolate(1e6+f), 0))'
2478 :gain_entry='entry(1000, 0); entry(1001,-INF); entry(1e6+1000,0)':multi=on
2483 Apply a flanging effect to the audio.
2485 The filter accepts the following options:
2489 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
2492 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
2495 Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
2499 Set percentage of delayed signal mixed with original. Range from 0 to 100.
2500 Default value is 71.
2503 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
2506 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
2507 Default value is @var{sinusoidal}.
2510 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
2511 Default value is 25.
2514 Set delay-line interpolation, @var{linear} or @var{quadratic}.
2515 Default is @var{linear}.
2520 Apply a high-pass filter with 3dB point frequency.
2521 The filter can be either single-pole, or double-pole (the default).
2522 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2524 The filter accepts the following options:
2528 Set frequency in Hz. Default is 3000.
2531 Set number of poles. Default is 2.
2534 Set method to specify band-width of filter.
2547 Specify the band-width of a filter in width_type units.
2548 Applies only to double-pole filter.
2549 The default is 0.707q and gives a Butterworth response.
2554 Join multiple input streams into one multi-channel stream.
2556 It accepts the following parameters:
2560 The number of input streams. It defaults to 2.
2562 @item channel_layout
2563 The desired output channel layout. It defaults to stereo.
2566 Map channels from inputs to output. The argument is a '|'-separated list of
2567 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
2568 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
2569 can be either the name of the input channel (e.g. FL for front left) or its
2570 index in the specified input stream. @var{out_channel} is the name of the output
2574 The filter will attempt to guess the mappings when they are not specified
2575 explicitly. It does so by first trying to find an unused matching input channel
2576 and if that fails it picks the first unused input channel.
2578 Join 3 inputs (with properly set channel layouts):
2580 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
2583 Build a 5.1 output from 6 single-channel streams:
2585 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
2586 'join=inputs=6:channel_layout=5.1:map=0.0-FL|1.0-FR|2.0-FC|3.0-SL|4.0-SR|5.0-LFE'
2592 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
2594 To enable compilation of this filter you need to configure FFmpeg with
2595 @code{--enable-ladspa}.
2599 Specifies the name of LADSPA plugin library to load. If the environment
2600 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
2601 each one of the directories specified by the colon separated list in
2602 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
2603 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
2604 @file{/usr/lib/ladspa/}.
2607 Specifies the plugin within the library. Some libraries contain only
2608 one plugin, but others contain many of them. If this is not set filter
2609 will list all available plugins within the specified library.
2612 Set the '|' separated list of controls which are zero or more floating point
2613 values that determine the behavior of the loaded plugin (for example delay,
2615 Controls need to be defined using the following syntax:
2616 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
2617 @var{valuei} is the value set on the @var{i}-th control.
2618 Alternatively they can be also defined using the following syntax:
2619 @var{value0}|@var{value1}|@var{value2}|..., where
2620 @var{valuei} is the value set on the @var{i}-th control.
2621 If @option{controls} is set to @code{help}, all available controls and
2622 their valid ranges are printed.
2624 @item sample_rate, s
2625 Specify the sample rate, default to 44100. Only used if plugin have
2629 Set the number of samples per channel per each output frame, default
2630 is 1024. Only used if plugin have zero inputs.
2633 Set the minimum duration of the sourced audio. See
2634 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2635 for the accepted syntax.
2636 Note that the resulting duration may be greater than the specified duration,
2637 as the generated audio is always cut at the end of a complete frame.
2638 If not specified, or the expressed duration is negative, the audio is
2639 supposed to be generated forever.
2640 Only used if plugin have zero inputs.
2644 @subsection Examples
2648 List all available plugins within amp (LADSPA example plugin) library:
2654 List all available controls and their valid ranges for @code{vcf_notch}
2655 plugin from @code{VCF} library:
2657 ladspa=f=vcf:p=vcf_notch:c=help
2661 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
2664 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
2668 Add reverberation to the audio using TAP-plugins
2669 (Tom's Audio Processing plugins):
2671 ladspa=file=tap_reverb:tap_reverb
2675 Generate white noise, with 0.2 amplitude:
2677 ladspa=file=cmt:noise_source_white:c=c0=.2
2681 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
2682 @code{C* Audio Plugin Suite} (CAPS) library:
2684 ladspa=file=caps:Click:c=c1=20'
2688 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
2690 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
2694 Increase volume by 20dB using fast lookahead limiter from Steve Harris
2695 @code{SWH Plugins} collection:
2697 ladspa=fast_lookahead_limiter_1913:fastLookaheadLimiter:20|0|2
2701 Attenuate low frequencies using Multiband EQ from Steve Harris
2702 @code{SWH Plugins} collection:
2704 ladspa=mbeq_1197:mbeq:-24|-24|-24|0|0|0|0|0|0|0|0|0|0|0|0
2708 @subsection Commands
2710 This filter supports the following commands:
2713 Modify the @var{N}-th control value.
2715 If the specified value is not valid, it is ignored and prior one is kept.
2720 EBU R128 loudness normalization. Includes both dynamic and linear normalization modes.
2721 Support for both single pass (livestreams, files) and double pass (files) modes.
2722 This algorithm can target IL, LRA, and maximum true peak.
2724 To enable compilation of this filter you need to configure FFmpeg with
2725 @code{--enable-libebur128}.
2727 The filter accepts the following options:
2731 Set integrated loudness target.
2732 Range is -70.0 - -5.0. Default value is -24.0.
2735 Set loudness range target.
2736 Range is 1.0 - 20.0. Default value is 7.0.
2739 Set maximum true peak.
2740 Range is -9.0 - +0.0. Default value is -2.0.
2742 @item measured_I, measured_i
2743 Measured IL of input file.
2744 Range is -99.0 - +0.0.
2746 @item measured_LRA, measured_lra
2747 Measured LRA of input file.
2748 Range is 0.0 - 99.0.
2750 @item measured_TP, measured_tp
2751 Measured true peak of input file.
2752 Range is -99.0 - +99.0.
2754 @item measured_thresh
2755 Measured threshold of input file.
2756 Range is -99.0 - +0.0.
2759 Set offset gain. Gain is applied before the true-peak limiter.
2760 Range is -99.0 - +99.0. Default is +0.0.
2763 Normalize linearly if possible.
2764 measured_I, measured_LRA, measured_TP, and measured_thresh must also
2765 to be specified in order to use this mode.
2766 Options are true or false. Default is true.
2769 Treat mono input files as "dual-mono". If a mono file is intended for playback
2770 on a stereo system, its EBU R128 measurement will be perceptually incorrect.
2771 If set to @code{true}, this option will compensate for this effect.
2772 Multi-channel input files are not affected by this option.
2773 Options are true or false. Default is false.
2776 Set print format for stats. Options are summary, json, or none.
2777 Default value is none.
2782 Apply a low-pass filter with 3dB point frequency.
2783 The filter can be either single-pole or double-pole (the default).
2784 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2786 The filter accepts the following options:
2790 Set frequency in Hz. Default is 500.
2793 Set number of poles. Default is 2.
2796 Set method to specify band-width of filter.
2809 Specify the band-width of a filter in width_type units.
2810 Applies only to double-pole filter.
2811 The default is 0.707q and gives a Butterworth response.
2817 Mix channels with specific gain levels. The filter accepts the output
2818 channel layout followed by a set of channels definitions.
2820 This filter is also designed to efficiently remap the channels of an audio
2823 The filter accepts parameters of the form:
2824 "@var{l}|@var{outdef}|@var{outdef}|..."
2828 output channel layout or number of channels
2831 output channel specification, of the form:
2832 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
2835 output channel to define, either a channel name (FL, FR, etc.) or a channel
2836 number (c0, c1, etc.)
2839 multiplicative coefficient for the channel, 1 leaving the volume unchanged
2842 input channel to use, see out_name for details; it is not possible to mix
2843 named and numbered input channels
2846 If the `=' in a channel specification is replaced by `<', then the gains for
2847 that specification will be renormalized so that the total is 1, thus
2848 avoiding clipping noise.
2850 @subsection Mixing examples
2852 For example, if you want to down-mix from stereo to mono, but with a bigger
2853 factor for the left channel:
2855 pan=1c|c0=0.9*c0+0.1*c1
2858 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
2859 7-channels surround:
2861 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
2864 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
2865 that should be preferred (see "-ac" option) unless you have very specific
2868 @subsection Remapping examples
2870 The channel remapping will be effective if, and only if:
2873 @item gain coefficients are zeroes or ones,
2874 @item only one input per channel output,
2877 If all these conditions are satisfied, the filter will notify the user ("Pure
2878 channel mapping detected"), and use an optimized and lossless method to do the
2881 For example, if you have a 5.1 source and want a stereo audio stream by
2882 dropping the extra channels:
2884 pan="stereo| c0=FL | c1=FR"
2887 Given the same source, you can also switch front left and front right channels
2888 and keep the input channel layout:
2890 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
2893 If the input is a stereo audio stream, you can mute the front left channel (and
2894 still keep the stereo channel layout) with:
2899 Still with a stereo audio stream input, you can copy the right channel in both
2900 front left and right:
2902 pan="stereo| c0=FR | c1=FR"
2907 ReplayGain scanner filter. This filter takes an audio stream as an input and
2908 outputs it unchanged.
2909 At end of filtering it displays @code{track_gain} and @code{track_peak}.
2913 Convert the audio sample format, sample rate and channel layout. It is
2914 not meant to be used directly.
2917 Apply time-stretching and pitch-shifting with librubberband.
2919 The filter accepts the following options:
2923 Set tempo scale factor.
2926 Set pitch scale factor.
2929 Set transients detector.
2930 Possible values are:
2939 Possible values are:
2948 Possible values are:
2955 Set processing window size.
2956 Possible values are:
2965 Possible values are:
2972 Enable formant preservation when shift pitching.
2973 Possible values are:
2981 Possible values are:
2990 Possible values are:
2997 @section sidechaincompress
2999 This filter acts like normal compressor but has the ability to compress
3000 detected signal using second input signal.
3001 It needs two input streams and returns one output stream.
3002 First input stream will be processed depending on second stream signal.
3003 The filtered signal then can be filtered with other filters in later stages of
3004 processing. See @ref{pan} and @ref{amerge} filter.
3006 The filter accepts the following options:
3010 Set input gain. Default is 1. Range is between 0.015625 and 64.
3013 If a signal of second stream raises above this level it will affect the gain
3014 reduction of first stream.
3015 By default is 0.125. Range is between 0.00097563 and 1.
3018 Set a ratio about which the signal is reduced. 1:2 means that if the level
3019 raised 4dB above the threshold, it will be only 2dB above after the reduction.
3020 Default is 2. Range is between 1 and 20.
3023 Amount of milliseconds the signal has to rise above the threshold before gain
3024 reduction starts. Default is 20. Range is between 0.01 and 2000.
3027 Amount of milliseconds the signal has to fall below the threshold before
3028 reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
3031 Set the amount by how much signal will be amplified after processing.
3032 Default is 2. Range is from 1 and 64.
3035 Curve the sharp knee around the threshold to enter gain reduction more softly.
3036 Default is 2.82843. Range is between 1 and 8.
3039 Choose if the @code{average} level between all channels of side-chain stream
3040 or the louder(@code{maximum}) channel of side-chain stream affects the
3041 reduction. Default is @code{average}.
3044 Should the exact signal be taken in case of @code{peak} or an RMS one in case
3045 of @code{rms}. Default is @code{rms} which is mainly smoother.
3048 Set sidechain gain. Default is 1. Range is between 0.015625 and 64.
3051 How much to use compressed signal in output. Default is 1.
3052 Range is between 0 and 1.
3055 @subsection Examples
3059 Full ffmpeg example taking 2 audio inputs, 1st input to be compressed
3060 depending on the signal of 2nd input and later compressed signal to be
3061 merged with 2nd input:
3063 ffmpeg -i main.flac -i sidechain.flac -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress[compr];[compr][mix]amerge"
3067 @section sidechaingate
3069 A sidechain gate acts like a normal (wideband) gate but has the ability to
3070 filter the detected signal before sending it to the gain reduction stage.
3071 Normally a gate uses the full range signal to detect a level above the
3073 For example: If you cut all lower frequencies from your sidechain signal
3074 the gate will decrease the volume of your track only if not enough highs
3075 appear. With this technique you are able to reduce the resonation of a
3076 natural drum or remove "rumbling" of muted strokes from a heavily distorted
3078 It needs two input streams and returns one output stream.
3079 First input stream will be processed depending on second stream signal.
3081 The filter accepts the following options:
3085 Set input level before filtering.
3086 Default is 1. Allowed range is from 0.015625 to 64.
3089 Set the level of gain reduction when the signal is below the threshold.
3090 Default is 0.06125. Allowed range is from 0 to 1.
3093 If a signal rises above this level the gain reduction is released.
3094 Default is 0.125. Allowed range is from 0 to 1.
3097 Set a ratio about which the signal is reduced.
3098 Default is 2. Allowed range is from 1 to 9000.
3101 Amount of milliseconds the signal has to rise above the threshold before gain
3103 Default is 20 milliseconds. Allowed range is from 0.01 to 9000.
3106 Amount of milliseconds the signal has to fall below the threshold before the
3107 reduction is increased again. Default is 250 milliseconds.
3108 Allowed range is from 0.01 to 9000.
3111 Set amount of amplification of signal after processing.
3112 Default is 1. Allowed range is from 1 to 64.
3115 Curve the sharp knee around the threshold to enter gain reduction more softly.
3116 Default is 2.828427125. Allowed range is from 1 to 8.
3119 Choose if exact signal should be taken for detection or an RMS like one.
3120 Default is rms. Can be peak or rms.
3123 Choose if the average level between all channels or the louder channel affects
3125 Default is average. Can be average or maximum.
3128 Set sidechain gain. Default is 1. Range is from 0.015625 to 64.
3131 @section silencedetect
3133 Detect silence in an audio stream.
3135 This filter logs a message when it detects that the input audio volume is less
3136 or equal to a noise tolerance value for a duration greater or equal to the
3137 minimum detected noise duration.
3139 The printed times and duration are expressed in seconds.
3141 The filter accepts the following options:
3145 Set silence duration until notification (default is 2 seconds).
3148 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
3149 specified value) or amplitude ratio. Default is -60dB, or 0.001.
3152 @subsection Examples
3156 Detect 5 seconds of silence with -50dB noise tolerance:
3158 silencedetect=n=-50dB:d=5
3162 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
3163 tolerance in @file{silence.mp3}:
3165 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
3169 @section silenceremove
3171 Remove silence from the beginning, middle or end of the audio.
3173 The filter accepts the following options:
3177 This value is used to indicate if audio should be trimmed at beginning of
3178 the audio. A value of zero indicates no silence should be trimmed from the
3179 beginning. When specifying a non-zero value, it trims audio up until it
3180 finds non-silence. Normally, when trimming silence from beginning of audio
3181 the @var{start_periods} will be @code{1} but it can be increased to higher
3182 values to trim all audio up to specific count of non-silence periods.
3183 Default value is @code{0}.
3185 @item start_duration
3186 Specify the amount of time that non-silence must be detected before it stops
3187 trimming audio. By increasing the duration, bursts of noises can be treated
3188 as silence and trimmed off. Default value is @code{0}.
3190 @item start_threshold
3191 This indicates what sample value should be treated as silence. For digital
3192 audio, a value of @code{0} may be fine but for audio recorded from analog,
3193 you may wish to increase the value to account for background noise.
3194 Can be specified in dB (in case "dB" is appended to the specified value)
3195 or amplitude ratio. Default value is @code{0}.
3198 Set the count for trimming silence from the end of audio.
3199 To remove silence from the middle of a file, specify a @var{stop_periods}
3200 that is negative. This value is then treated as a positive value and is
3201 used to indicate the effect should restart processing as specified by
3202 @var{start_periods}, making it suitable for removing periods of silence
3203 in the middle of the audio.
3204 Default value is @code{0}.
3207 Specify a duration of silence that must exist before audio is not copied any
3208 more. By specifying a higher duration, silence that is wanted can be left in
3210 Default value is @code{0}.
3212 @item stop_threshold
3213 This is the same as @option{start_threshold} but for trimming silence from
3215 Can be specified in dB (in case "dB" is appended to the specified value)
3216 or amplitude ratio. Default value is @code{0}.
3219 This indicate that @var{stop_duration} length of audio should be left intact
3220 at the beginning of each period of silence.
3221 For example, if you want to remove long pauses between words but do not want
3222 to remove the pauses completely. Default value is @code{0}.
3225 Set how is silence detected. Can be @code{rms} or @code{peak}. Second is faster
3226 and works better with digital silence which is exactly 0.
3227 Default value is @code{rms}.
3230 Set ratio used to calculate size of window for detecting silence.
3231 Default value is @code{0.02}. Allowed range is from @code{0} to @code{10}.
3234 @subsection Examples
3238 The following example shows how this filter can be used to start a recording
3239 that does not contain the delay at the start which usually occurs between
3240 pressing the record button and the start of the performance:
3242 silenceremove=1:5:0.02
3246 Trim all silence encountered from begining to end where there is more than 1
3247 second of silence in audio:
3249 silenceremove=0:0:0:-1:1:-90dB
3255 SOFAlizer uses head-related transfer functions (HRTFs) to create virtual
3256 loudspeakers around the user for binaural listening via headphones (audio
3257 formats up to 9 channels supported).
3258 The HRTFs are stored in SOFA files (see @url{http://www.sofacoustics.org/} for a database).
3259 SOFAlizer is developed at the Acoustics Research Institute (ARI) of the
3260 Austrian Academy of Sciences.
3262 To enable compilation of this filter you need to configure FFmpeg with
3263 @code{--enable-netcdf}.
3265 The filter accepts the following options:
3269 Set the SOFA file used for rendering.
3272 Set gain applied to audio. Value is in dB. Default is 0.
3275 Set rotation of virtual loudspeakers in deg. Default is 0.
3278 Set elevation of virtual speakers in deg. Default is 0.
3281 Set distance in meters between loudspeakers and the listener with near-field
3282 HRTFs. Default is 1.
3285 Set processing type. Can be @var{time} or @var{freq}. @var{time} is
3286 processing audio in time domain which is slow.
3287 @var{freq} is processing audio in frequency domain which is fast.
3288 Default is @var{freq}.
3291 Set custom positions of virtual loudspeakers. Syntax for this option is:
3292 <CH> <AZIM> <ELEV>[|<CH> <AZIM> <ELEV>|...].
3293 Each virtual loudspeaker is described with short channel name following with
3294 azimuth and elevation in degreees.
3295 Each virtual loudspeaker description is separated by '|'.
3296 For example to override front left and front right channel positions use:
3297 'speakers=FL 45 15|FR 345 15'.
3298 Descriptions with unrecognised channel names are ignored.
3301 @subsection Examples
3305 Using ClubFritz6 sofa file:
3307 sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=1
3311 Using ClubFritz12 sofa file and bigger radius with small rotation:
3313 sofalizer=sofa=/path/to/ClubFritz12.sofa:type=freq:radius=2:rotation=5
3317 Similar as above but with custom speaker positions for front left, front right, rear left and rear right
3318 and also with custom gain:
3320 "sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=2:speakers=FL 45|FR 315|RL 135|RR 225:gain=28"
3324 @section stereotools
3326 This filter has some handy utilities to manage stereo signals, for converting
3327 M/S stereo recordings to L/R signal while having control over the parameters
3328 or spreading the stereo image of master track.
3330 The filter accepts the following options:
3334 Set input level before filtering for both channels. Defaults is 1.
3335 Allowed range is from 0.015625 to 64.
3338 Set output level after filtering for both channels. Defaults is 1.
3339 Allowed range is from 0.015625 to 64.
3342 Set input balance between both channels. Default is 0.
3343 Allowed range is from -1 to 1.
3346 Set output balance between both channels. Default is 0.
3347 Allowed range is from -1 to 1.
3350 Enable softclipping. Results in analog distortion instead of harsh digital 0dB
3351 clipping. Disabled by default.
3354 Mute the left channel. Disabled by default.
3357 Mute the right channel. Disabled by default.
3360 Change the phase of the left channel. Disabled by default.
3363 Change the phase of the right channel. Disabled by default.
3366 Set stereo mode. Available values are:
3370 Left/Right to Left/Right, this is default.
3373 Left/Right to Mid/Side.
3376 Mid/Side to Left/Right.
3379 Left/Right to Left/Left.
3382 Left/Right to Right/Right.
3385 Left/Right to Left + Right.
3388 Left/Right to Right/Left.
3392 Set level of side signal. Default is 1.
3393 Allowed range is from 0.015625 to 64.
3396 Set balance of side signal. Default is 0.
3397 Allowed range is from -1 to 1.
3400 Set level of the middle signal. Default is 1.
3401 Allowed range is from 0.015625 to 64.
3404 Set middle signal pan. Default is 0. Allowed range is from -1 to 1.
3407 Set stereo base between mono and inversed channels. Default is 0.
3408 Allowed range is from -1 to 1.
3411 Set delay in milliseconds how much to delay left from right channel and
3412 vice versa. Default is 0. Allowed range is from -20 to 20.
3415 Set S/C level. Default is 1. Allowed range is from 1 to 100.
3418 Set the stereo phase in degrees. Default is 0. Allowed range is from 0 to 360.
3421 @subsection Examples
3425 Apply karaoke like effect:
3427 stereotools=mlev=0.015625
3431 Convert M/S signal to L/R:
3433 "stereotools=mode=ms>lr"
3437 @section stereowiden
3439 This filter enhance the stereo effect by suppressing signal common to both
3440 channels and by delaying the signal of left into right and vice versa,
3441 thereby widening the stereo effect.
3443 The filter accepts the following options:
3447 Time in milliseconds of the delay of left signal into right and vice versa.
3448 Default is 20 milliseconds.
3451 Amount of gain in delayed signal into right and vice versa. Gives a delay
3452 effect of left signal in right output and vice versa which gives widening
3453 effect. Default is 0.3.
3456 Cross feed of left into right with inverted phase. This helps in suppressing
3457 the mono. If the value is 1 it will cancel all the signal common to both
3458 channels. Default is 0.3.
3461 Set level of input signal of original channel. Default is 0.8.
3466 Use the NVIDIA Performance Primitives (libnpp) to perform scaling and/or pixel
3467 format conversion on CUDA video frames. Setting the output width and height
3468 works in the same way as for the @var{scale} filter.
3470 The following additional options are accepted:
3473 The pixel format of the output CUDA frames. If set to the string "same" (the
3474 default), the input format will be kept. Note that automatic format negotiation
3475 and conversion is not yet supported for hardware frames
3478 The interpolation algorithm used for resizing. One of the following:
3485 @item cubic2p_bspline
3486 2-parameter cubic (B=1, C=0)
3488 @item cubic2p_catmullrom
3489 2-parameter cubic (B=0, C=1/2)
3491 @item cubic2p_b05c03
3492 2-parameter cubic (B=1/2, C=3/10)
3503 Select frames to pass in output.
3507 Boost or cut treble (upper) frequencies of the audio using a two-pole
3508 shelving filter with a response similar to that of a standard
3509 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
3511 The filter accepts the following options:
3515 Give the gain at whichever is the lower of ~22 kHz and the
3516 Nyquist frequency. Its useful range is about -20 (for a large cut)
3517 to +20 (for a large boost). Beware of clipping when using a positive gain.
3520 Set the filter's central frequency and so can be used
3521 to extend or reduce the frequency range to be boosted or cut.
3522 The default value is @code{3000} Hz.
3525 Set method to specify band-width of filter.
3538 Determine how steep is the filter's shelf transition.
3543 Sinusoidal amplitude modulation.
3545 The filter accepts the following options:
3549 Modulation frequency in Hertz. Modulation frequencies in the subharmonic range
3550 (20 Hz or lower) will result in a tremolo effect.
3551 This filter may also be used as a ring modulator by specifying
3552 a modulation frequency higher than 20 Hz.
3553 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
3556 Depth of modulation as a percentage. Range is 0.0 - 1.0.
3557 Default value is 0.5.
3562 Sinusoidal phase modulation.
3564 The filter accepts the following options:
3568 Modulation frequency in Hertz.
3569 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
3572 Depth of modulation as a percentage. Range is 0.0 - 1.0.
3573 Default value is 0.5.
3578 Adjust the input audio volume.
3580 It accepts the following parameters:
3584 Set audio volume expression.
3586 Output values are clipped to the maximum value.
3588 The output audio volume is given by the relation:
3590 @var{output_volume} = @var{volume} * @var{input_volume}
3593 The default value for @var{volume} is "1.0".
3596 This parameter represents the mathematical precision.
3598 It determines which input sample formats will be allowed, which affects the
3599 precision of the volume scaling.
3603 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
3605 32-bit floating-point; this limits input sample format to FLT. (default)
3607 64-bit floating-point; this limits input sample format to DBL.
3611 Choose the behaviour on encountering ReplayGain side data in input frames.
3615 Remove ReplayGain side data, ignoring its contents (the default).
3618 Ignore ReplayGain side data, but leave it in the frame.
3621 Prefer the track gain, if present.
3624 Prefer the album gain, if present.
3627 @item replaygain_preamp
3628 Pre-amplification gain in dB to apply to the selected replaygain gain.
3630 Default value for @var{replaygain_preamp} is 0.0.
3633 Set when the volume expression is evaluated.
3635 It accepts the following values:
3638 only evaluate expression once during the filter initialization, or
3639 when the @samp{volume} command is sent
3642 evaluate expression for each incoming frame
3645 Default value is @samp{once}.
3648 The volume expression can contain the following parameters.
3652 frame number (starting at zero)
3655 @item nb_consumed_samples
3656 number of samples consumed by the filter
3658 number of samples in the current frame
3660 original frame position in the file
3666 PTS at start of stream
3668 time at start of stream
3674 last set volume value
3677 Note that when @option{eval} is set to @samp{once} only the
3678 @var{sample_rate} and @var{tb} variables are available, all other
3679 variables will evaluate to NAN.
3681 @subsection Commands
3683 This filter supports the following commands:
3686 Modify the volume expression.
3687 The command accepts the same syntax of the corresponding option.
3689 If the specified expression is not valid, it is kept at its current
3691 @item replaygain_noclip
3692 Prevent clipping by limiting the gain applied.
3694 Default value for @var{replaygain_noclip} is 1.
3698 @subsection Examples
3702 Halve the input audio volume:
3706 volume=volume=-6.0206dB
3709 In all the above example the named key for @option{volume} can be
3710 omitted, for example like in:
3716 Increase input audio power by 6 decibels using fixed-point precision:
3718 volume=volume=6dB:precision=fixed
3722 Fade volume after time 10 with an annihilation period of 5 seconds:
3724 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
3728 @section volumedetect
3730 Detect the volume of the input video.
3732 The filter has no parameters. The input is not modified. Statistics about
3733 the volume will be printed in the log when the input stream end is reached.
3735 In particular it will show the mean volume (root mean square), maximum
3736 volume (on a per-sample basis), and the beginning of a histogram of the
3737 registered volume values (from the maximum value to a cumulated 1/1000 of
3740 All volumes are in decibels relative to the maximum PCM value.
3742 @subsection Examples
3744 Here is an excerpt of the output:
3746 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
3747 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
3748 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
3749 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
3750 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
3751 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
3752 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
3753 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
3754 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
3760 The mean square energy is approximately -27 dB, or 10^-2.7.
3762 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
3764 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
3767 In other words, raising the volume by +4 dB does not cause any clipping,
3768 raising it by +5 dB causes clipping for 6 samples, etc.
3770 @c man end AUDIO FILTERS
3772 @chapter Audio Sources
3773 @c man begin AUDIO SOURCES
3775 Below is a description of the currently available audio sources.
3779 Buffer audio frames, and make them available to the filter chain.
3781 This source is mainly intended for a programmatic use, in particular
3782 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
3784 It accepts the following parameters:
3788 The timebase which will be used for timestamps of submitted frames. It must be
3789 either a floating-point number or in @var{numerator}/@var{denominator} form.
3792 The sample rate of the incoming audio buffers.
3795 The sample format of the incoming audio buffers.
3796 Either a sample format name or its corresponding integer representation from
3797 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
3799 @item channel_layout
3800 The channel layout of the incoming audio buffers.
3801 Either a channel layout name from channel_layout_map in
3802 @file{libavutil/channel_layout.c} or its corresponding integer representation
3803 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
3806 The number of channels of the incoming audio buffers.
3807 If both @var{channels} and @var{channel_layout} are specified, then they
3812 @subsection Examples
3815 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
3818 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
3819 Since the sample format with name "s16p" corresponds to the number
3820 6 and the "stereo" channel layout corresponds to the value 0x3, this is
3823 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
3828 Generate an audio signal specified by an expression.
3830 This source accepts in input one or more expressions (one for each
3831 channel), which are evaluated and used to generate a corresponding
3834 This source accepts the following options:
3838 Set the '|'-separated expressions list for each separate channel. In case the
3839 @option{channel_layout} option is not specified, the selected channel layout
3840 depends on the number of provided expressions. Otherwise the last
3841 specified expression is applied to the remaining output channels.
3843 @item channel_layout, c
3844 Set the channel layout. The number of channels in the specified layout
3845 must be equal to the number of specified expressions.
3848 Set the minimum duration of the sourced audio. See
3849 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
3850 for the accepted syntax.
3851 Note that the resulting duration may be greater than the specified
3852 duration, as the generated audio is always cut at the end of a
3855 If not specified, or the expressed duration is negative, the audio is
3856 supposed to be generated forever.
3859 Set the number of samples per channel per each output frame,
3862 @item sample_rate, s
3863 Specify the sample rate, default to 44100.
3866 Each expression in @var{exprs} can contain the following constants:
3870 number of the evaluated sample, starting from 0
3873 time of the evaluated sample expressed in seconds, starting from 0
3880 @subsection Examples
3890 Generate a sin signal with frequency of 440 Hz, set sample rate to
3893 aevalsrc="sin(440*2*PI*t):s=8000"
3897 Generate a two channels signal, specify the channel layout (Front
3898 Center + Back Center) explicitly:
3900 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
3904 Generate white noise:
3906 aevalsrc="-2+random(0)"
3910 Generate an amplitude modulated signal:
3912 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
3916 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
3918 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
3925 The null audio source, return unprocessed audio frames. It is mainly useful
3926 as a template and to be employed in analysis / debugging tools, or as
3927 the source for filters which ignore the input data (for example the sox
3930 This source accepts the following options:
3934 @item channel_layout, cl
3936 Specifies the channel layout, and can be either an integer or a string
3937 representing a channel layout. The default value of @var{channel_layout}
3940 Check the channel_layout_map definition in
3941 @file{libavutil/channel_layout.c} for the mapping between strings and
3942 channel layout values.
3944 @item sample_rate, r
3945 Specifies the sample rate, and defaults to 44100.
3948 Set the number of samples per requested frames.
3952 @subsection Examples
3956 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
3958 anullsrc=r=48000:cl=4
3962 Do the same operation with a more obvious syntax:
3964 anullsrc=r=48000:cl=mono
3968 All the parameters need to be explicitly defined.
3972 Synthesize a voice utterance using the libflite library.
3974 To enable compilation of this filter you need to configure FFmpeg with
3975 @code{--enable-libflite}.
3977 Note that the flite library is not thread-safe.
3979 The filter accepts the following options:
3984 If set to 1, list the names of the available voices and exit
3985 immediately. Default value is 0.
3988 Set the maximum number of samples per frame. Default value is 512.
3991 Set the filename containing the text to speak.
3994 Set the text to speak.
3997 Set the voice to use for the speech synthesis. Default value is
3998 @code{kal}. See also the @var{list_voices} option.
4001 @subsection Examples
4005 Read from file @file{speech.txt}, and synthesize the text using the
4006 standard flite voice:
4008 flite=textfile=speech.txt
4012 Read the specified text selecting the @code{slt} voice:
4014 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
4018 Input text to ffmpeg:
4020 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
4024 Make @file{ffplay} speak the specified text, using @code{flite} and
4025 the @code{lavfi} device:
4027 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
4031 For more information about libflite, check:
4032 @url{http://www.speech.cs.cmu.edu/flite/}
4036 Generate a noise audio signal.
4038 The filter accepts the following options:
4041 @item sample_rate, r
4042 Specify the sample rate. Default value is 48000 Hz.
4045 Specify the amplitude (0.0 - 1.0) of the generated audio stream. Default value
4049 Specify the duration of the generated audio stream. Not specifying this option
4050 results in noise with an infinite length.
4052 @item color, colour, c
4053 Specify the color of noise. Available noise colors are white, pink, and brown.
4054 Default color is white.
4057 Specify a value used to seed the PRNG.
4060 Set the number of samples per each output frame, default is 1024.
4063 @subsection Examples
4068 Generate 60 seconds of pink noise, with a 44.1 kHz sampling rate and an amplitude of 0.5:
4070 anoisesrc=d=60:c=pink:r=44100:a=0.5
4076 Generate an audio signal made of a sine wave with amplitude 1/8.
4078 The audio signal is bit-exact.
4080 The filter accepts the following options:
4085 Set the carrier frequency. Default is 440 Hz.
4087 @item beep_factor, b
4088 Enable a periodic beep every second with frequency @var{beep_factor} times
4089 the carrier frequency. Default is 0, meaning the beep is disabled.
4091 @item sample_rate, r
4092 Specify the sample rate, default is 44100.
4095 Specify the duration of the generated audio stream.
4097 @item samples_per_frame
4098 Set the number of samples per output frame.
4100 The expression can contain the following constants:
4104 The (sequential) number of the output audio frame, starting from 0.
4107 The PTS (Presentation TimeStamp) of the output audio frame,
4108 expressed in @var{TB} units.
4111 The PTS of the output audio frame, expressed in seconds.
4114 The timebase of the output audio frames.
4117 Default is @code{1024}.
4120 @subsection Examples
4125 Generate a simple 440 Hz sine wave:
4131 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
4135 sine=frequency=220:beep_factor=4:duration=5
4139 Generate a 1 kHz sine wave following @code{1602,1601,1602,1601,1602} NTSC
4142 sine=1000:samples_per_frame='st(0,mod(n,5)); 1602-not(not(eq(ld(0),1)+eq(ld(0),3)))'
4146 @c man end AUDIO SOURCES
4148 @chapter Audio Sinks
4149 @c man begin AUDIO SINKS
4151 Below is a description of the currently available audio sinks.
4153 @section abuffersink
4155 Buffer audio frames, and make them available to the end of filter chain.
4157 This sink is mainly intended for programmatic use, in particular
4158 through the interface defined in @file{libavfilter/buffersink.h}
4159 or the options system.
4161 It accepts a pointer to an AVABufferSinkContext structure, which
4162 defines the incoming buffers' formats, to be passed as the opaque
4163 parameter to @code{avfilter_init_filter} for initialization.
4166 Null audio sink; do absolutely nothing with the input audio. It is
4167 mainly useful as a template and for use in analysis / debugging
4170 @c man end AUDIO SINKS
4172 @chapter Video Filters
4173 @c man begin VIDEO FILTERS
4175 When you configure your FFmpeg build, you can disable any of the
4176 existing filters using @code{--disable-filters}.
4177 The configure output will show the video filters included in your
4180 Below is a description of the currently available video filters.
4182 @section alphaextract
4184 Extract the alpha component from the input as a grayscale video. This
4185 is especially useful with the @var{alphamerge} filter.
4189 Add or replace the alpha component of the primary input with the
4190 grayscale value of a second input. This is intended for use with
4191 @var{alphaextract} to allow the transmission or storage of frame
4192 sequences that have alpha in a format that doesn't support an alpha
4195 For example, to reconstruct full frames from a normal YUV-encoded video
4196 and a separate video created with @var{alphaextract}, you might use:
4198 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
4201 Since this filter is designed for reconstruction, it operates on frame
4202 sequences without considering timestamps, and terminates when either
4203 input reaches end of stream. This will cause problems if your encoding
4204 pipeline drops frames. If you're trying to apply an image as an
4205 overlay to a video stream, consider the @var{overlay} filter instead.
4209 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
4210 and libavformat to work. On the other hand, it is limited to ASS (Advanced
4211 Substation Alpha) subtitles files.
4213 This filter accepts the following option in addition to the common options from
4214 the @ref{subtitles} filter:
4218 Set the shaping engine
4220 Available values are:
4223 The default libass shaping engine, which is the best available.
4225 Fast, font-agnostic shaper that can do only substitutions
4227 Slower shaper using OpenType for substitutions and positioning
4230 The default is @code{auto}.
4234 Apply an Adaptive Temporal Averaging Denoiser to the video input.
4236 The filter accepts the following options:
4240 Set threshold A for 1st plane. Default is 0.02.
4241 Valid range is 0 to 0.3.
4244 Set threshold B for 1st plane. Default is 0.04.
4245 Valid range is 0 to 5.
4248 Set threshold A for 2nd plane. Default is 0.02.
4249 Valid range is 0 to 0.3.
4252 Set threshold B for 2nd plane. Default is 0.04.
4253 Valid range is 0 to 5.
4256 Set threshold A for 3rd plane. Default is 0.02.
4257 Valid range is 0 to 0.3.
4260 Set threshold B for 3rd plane. Default is 0.04.
4261 Valid range is 0 to 5.
4263 Threshold A is designed to react on abrupt changes in the input signal and
4264 threshold B is designed to react on continuous changes in the input signal.
4267 Set number of frames filter will use for averaging. Default is 33. Must be odd
4268 number in range [5, 129].
4273 Compute the bounding box for the non-black pixels in the input frame
4276 This filter computes the bounding box containing all the pixels with a
4277 luminance value greater than the minimum allowed value.
4278 The parameters describing the bounding box are printed on the filter
4281 The filter accepts the following option:
4285 Set the minimal luminance value. Default is @code{16}.
4288 @section blackdetect
4290 Detect video intervals that are (almost) completely black. Can be
4291 useful to detect chapter transitions, commercials, or invalid
4292 recordings. Output lines contains the time for the start, end and
4293 duration of the detected black interval expressed in seconds.
4295 In order to display the output lines, you need to set the loglevel at
4296 least to the AV_LOG_INFO value.
4298 The filter accepts the following options:
4301 @item black_min_duration, d
4302 Set the minimum detected black duration expressed in seconds. It must
4303 be a non-negative floating point number.
4305 Default value is 2.0.
4307 @item picture_black_ratio_th, pic_th
4308 Set the threshold for considering a picture "black".
4309 Express the minimum value for the ratio:
4311 @var{nb_black_pixels} / @var{nb_pixels}
4314 for which a picture is considered black.
4315 Default value is 0.98.
4317 @item pixel_black_th, pix_th
4318 Set the threshold for considering a pixel "black".
4320 The threshold expresses the maximum pixel luminance value for which a
4321 pixel is considered "black". The provided value is scaled according to
4322 the following equation:
4324 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
4327 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
4328 the input video format, the range is [0-255] for YUV full-range
4329 formats and [16-235] for YUV non full-range formats.
4331 Default value is 0.10.
4334 The following example sets the maximum pixel threshold to the minimum
4335 value, and detects only black intervals of 2 or more seconds:
4337 blackdetect=d=2:pix_th=0.00
4342 Detect frames that are (almost) completely black. Can be useful to
4343 detect chapter transitions or commercials. Output lines consist of
4344 the frame number of the detected frame, the percentage of blackness,
4345 the position in the file if known or -1 and the timestamp in seconds.
4347 In order to display the output lines, you need to set the loglevel at
4348 least to the AV_LOG_INFO value.
4350 It accepts the following parameters:
4355 The percentage of the pixels that have to be below the threshold; it defaults to
4358 @item threshold, thresh
4359 The threshold below which a pixel value is considered black; it defaults to
4364 @section blend, tblend
4366 Blend two video frames into each other.
4368 The @code{blend} filter takes two input streams and outputs one
4369 stream, the first input is the "top" layer and second input is
4370 "bottom" layer. Output terminates when shortest input terminates.
4372 The @code{tblend} (time blend) filter takes two consecutive frames
4373 from one single stream, and outputs the result obtained by blending
4374 the new frame on top of the old frame.
4376 A description of the accepted options follows.
4384 Set blend mode for specific pixel component or all pixel components in case
4385 of @var{all_mode}. Default value is @code{normal}.
4387 Available values for component modes are:
4428 Set blend opacity for specific pixel component or all pixel components in case
4429 of @var{all_opacity}. Only used in combination with pixel component blend modes.
4436 Set blend expression for specific pixel component or all pixel components in case
4437 of @var{all_expr}. Note that related mode options will be ignored if those are set.
4439 The expressions can use the following variables:
4443 The sequential number of the filtered frame, starting from @code{0}.
4447 the coordinates of the current sample
4451 the width and height of currently filtered plane
4455 Width and height scale depending on the currently filtered plane. It is the
4456 ratio between the corresponding luma plane number of pixels and the current
4457 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4458 @code{0.5,0.5} for chroma planes.
4461 Time of the current frame, expressed in seconds.
4464 Value of pixel component at current location for first video frame (top layer).
4467 Value of pixel component at current location for second video frame (bottom layer).
4471 Force termination when the shortest input terminates. Default is
4472 @code{0}. This option is only defined for the @code{blend} filter.
4475 Continue applying the last bottom frame after the end of the stream. A value of
4476 @code{0} disable the filter after the last frame of the bottom layer is reached.
4477 Default is @code{1}. This option is only defined for the @code{blend} filter.
4480 @subsection Examples
4484 Apply transition from bottom layer to top layer in first 10 seconds:
4486 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
4490 Apply 1x1 checkerboard effect:
4492 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
4496 Apply uncover left effect:
4498 blend=all_expr='if(gte(N*SW+X,W),A,B)'
4502 Apply uncover down effect:
4504 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
4508 Apply uncover up-left effect:
4510 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
4514 Split diagonally video and shows top and bottom layer on each side:
4516 blend=all_expr=if(gt(X,Y*(W/H)),A,B)
4520 Display differences between the current and the previous frame:
4522 tblend=all_mode=difference128
4528 Apply a boxblur algorithm to the input video.
4530 It accepts the following parameters:
4534 @item luma_radius, lr
4535 @item luma_power, lp
4536 @item chroma_radius, cr
4537 @item chroma_power, cp
4538 @item alpha_radius, ar
4539 @item alpha_power, ap
4543 A description of the accepted options follows.
4546 @item luma_radius, lr
4547 @item chroma_radius, cr
4548 @item alpha_radius, ar
4549 Set an expression for the box radius in pixels used for blurring the
4550 corresponding input plane.
4552 The radius value must be a non-negative number, and must not be
4553 greater than the value of the expression @code{min(w,h)/2} for the
4554 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
4557 Default value for @option{luma_radius} is "2". If not specified,
4558 @option{chroma_radius} and @option{alpha_radius} default to the
4559 corresponding value set for @option{luma_radius}.
4561 The expressions can contain the following constants:
4565 The input width and height in pixels.
4569 The input chroma image width and height in pixels.
4573 The horizontal and vertical chroma subsample values. For example, for the
4574 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
4577 @item luma_power, lp
4578 @item chroma_power, cp
4579 @item alpha_power, ap
4580 Specify how many times the boxblur filter is applied to the
4581 corresponding plane.
4583 Default value for @option{luma_power} is 2. If not specified,
4584 @option{chroma_power} and @option{alpha_power} default to the
4585 corresponding value set for @option{luma_power}.
4587 A value of 0 will disable the effect.
4590 @subsection Examples
4594 Apply a boxblur filter with the luma, chroma, and alpha radii
4597 boxblur=luma_radius=2:luma_power=1
4602 Set the luma radius to 2, and alpha and chroma radius to 0:
4604 boxblur=2:1:cr=0:ar=0
4608 Set the luma and chroma radii to a fraction of the video dimension:
4610 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
4616 Deinterlace the input video ("bwdif" stands for "Bob Weaver
4617 Deinterlacing Filter").
4619 Motion adaptive deinterlacing based on yadif with the use of w3fdif and cubic
4620 interpolation algorithms.
4621 It accepts the following parameters:
4625 The interlacing mode to adopt. It accepts one of the following values:
4629 Output one frame for each frame.
4631 Output one frame for each field.
4634 The default value is @code{send_field}.
4637 The picture field parity assumed for the input interlaced video. It accepts one
4638 of the following values:
4642 Assume the top field is first.
4644 Assume the bottom field is first.
4646 Enable automatic detection of field parity.
4649 The default value is @code{auto}.
4650 If the interlacing is unknown or the decoder does not export this information,
4651 top field first will be assumed.
4654 Specify which frames to deinterlace. Accept one of the following
4659 Deinterlace all frames.
4661 Only deinterlace frames marked as interlaced.
4664 The default value is @code{all}.
4668 YUV colorspace color/chroma keying.
4670 The filter accepts the following options:
4674 The color which will be replaced with transparency.
4677 Similarity percentage with the key color.
4679 0.01 matches only the exact key color, while 1.0 matches everything.
4684 0.0 makes pixels either fully transparent, or not transparent at all.
4686 Higher values result in semi-transparent pixels, with a higher transparency
4687 the more similar the pixels color is to the key color.
4690 Signals that the color passed is already in YUV instead of RGB.
4692 Litteral colors like "green" or "red" don't make sense with this enabled anymore.
4693 This can be used to pass exact YUV values as hexadecimal numbers.
4696 @subsection Examples
4700 Make every green pixel in the input image transparent:
4702 ffmpeg -i input.png -vf chromakey=green out.png
4706 Overlay a greenscreen-video on top of a static black background.
4708 ffmpeg -f lavfi -i color=c=black:s=1280x720 -i video.mp4 -shortest -filter_complex "[1:v]chromakey=0x70de77:0.1:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.mkv
4714 Display CIE color diagram with pixels overlaid onto it.
4716 The filter acccepts the following options:
4731 @item uhdtv, rec2020
4744 Set what gamuts to draw.
4746 See @code{system} option for avaiable values.
4749 Set ciescope size, by default set to 512.
4752 Set intensity used to map input pixel values to CIE diagram.
4755 Set contrast used to draw tongue colors that are out of active color system gamut.
4758 Correct gamma displayed on scope, by default enabled.
4761 Show white point on CIE diagram, by default disabled.
4764 Set input gamma. Used only with XYZ input color space.
4769 Visualize information exported by some codecs.
4771 Some codecs can export information through frames using side-data or other
4772 means. For example, some MPEG based codecs export motion vectors through the
4773 @var{export_mvs} flag in the codec @option{flags2} option.
4775 The filter accepts the following option:
4779 Set motion vectors to visualize.
4781 Available flags for @var{mv} are:
4785 forward predicted MVs of P-frames
4787 forward predicted MVs of B-frames
4789 backward predicted MVs of B-frames
4793 Display quantization parameters using the chroma planes.
4796 Set motion vectors type to visualize. Includes MVs from all frames unless specified by @var{frame_type} option.
4798 Available flags for @var{mv_type} are:
4802 forward predicted MVs
4804 backward predicted MVs
4807 @item frame_type, ft
4808 Set frame type to visualize motion vectors of.
4810 Available flags for @var{frame_type} are:
4814 intra-coded frames (I-frames)
4816 predicted frames (P-frames)
4818 bi-directionally predicted frames (B-frames)
4822 @subsection Examples
4826 Visualize forward predicted MVs of all frames using @command{ffplay}:
4828 ffplay -flags2 +export_mvs input.mp4 -vf codecview=mv_type=fp
4832 Visualize multi-directionals MVs of P and B-Frames using @command{ffplay}:
4834 ffplay -flags2 +export_mvs input.mp4 -vf codecview=mv=pf+bf+bb
4838 @section colorbalance
4839 Modify intensity of primary colors (red, green and blue) of input frames.
4841 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
4842 regions for the red-cyan, green-magenta or blue-yellow balance.
4844 A positive adjustment value shifts the balance towards the primary color, a negative
4845 value towards the complementary color.
4847 The filter accepts the following options:
4853 Adjust red, green and blue shadows (darkest pixels).
4858 Adjust red, green and blue midtones (medium pixels).
4863 Adjust red, green and blue highlights (brightest pixels).
4865 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
4868 @subsection Examples
4872 Add red color cast to shadows:
4879 RGB colorspace color keying.
4881 The filter accepts the following options:
4885 The color which will be replaced with transparency.
4888 Similarity percentage with the key color.
4890 0.01 matches only the exact key color, while 1.0 matches everything.
4895 0.0 makes pixels either fully transparent, or not transparent at all.
4897 Higher values result in semi-transparent pixels, with a higher transparency
4898 the more similar the pixels color is to the key color.
4901 @subsection Examples
4905 Make every green pixel in the input image transparent:
4907 ffmpeg -i input.png -vf colorkey=green out.png
4911 Overlay a greenscreen-video on top of a static background image.
4913 ffmpeg -i background.png -i video.mp4 -filter_complex "[1:v]colorkey=0x3BBD1E:0.3:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.flv
4917 @section colorlevels
4919 Adjust video input frames using levels.
4921 The filter accepts the following options:
4928 Adjust red, green, blue and alpha input black point.
4929 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
4935 Adjust red, green, blue and alpha input white point.
4936 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
4938 Input levels are used to lighten highlights (bright tones), darken shadows
4939 (dark tones), change the balance of bright and dark tones.
4945 Adjust red, green, blue and alpha output black point.
4946 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
4952 Adjust red, green, blue and alpha output white point.
4953 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
4955 Output levels allows manual selection of a constrained output level range.
4958 @subsection Examples
4962 Make video output darker:
4964 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
4970 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
4974 Make video output lighter:
4976 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
4980 Increase brightness:
4982 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
4986 @section colorchannelmixer
4988 Adjust video input frames by re-mixing color channels.
4990 This filter modifies a color channel by adding the values associated to
4991 the other channels of the same pixels. For example if the value to
4992 modify is red, the output value will be:
4994 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
4997 The filter accepts the following options:
5004 Adjust contribution of input red, green, blue and alpha channels for output red channel.
5005 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
5011 Adjust contribution of input red, green, blue and alpha channels for output green channel.
5012 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
5018 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
5019 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
5025 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
5026 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
5028 Allowed ranges for options are @code{[-2.0, 2.0]}.
5031 @subsection Examples
5035 Convert source to grayscale:
5037 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
5040 Simulate sepia tones:
5042 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
5046 @section colormatrix
5048 Convert color matrix.
5050 The filter accepts the following options:
5055 Specify the source and destination color matrix. Both values must be
5058 The accepted values are:
5077 For example to convert from BT.601 to SMPTE-240M, use the command:
5079 colormatrix=bt601:smpte240m
5084 Convert colorspace, transfer characteristics or color primaries.
5086 The filter accepts the following options:
5090 Specify all color properties at once.
5092 The accepted values are:
5121 Specify output colorspace.
5123 The accepted values are:
5132 BT.470BG or BT.601-6 625
5135 SMPTE-170M or BT.601-6 525
5141 BT.2020 with non-constant luminance
5146 Specify output transfer characteristics.
5148 The accepted values are:
5154 Constant gamma of 2.2
5157 Constant gamma of 2.8
5160 SMPTE-170M, BT.601-6 625 or BT.601-6 525
5166 BT.2020 for 10-bits content
5169 BT.2020 for 12-bits content
5174 Specify output color primaries.
5176 The accepted values are:
5185 BT.470BG or BT.601-6 625
5188 SMPTE-170M or BT.601-6 525
5199 Specify output color range.
5201 The accepted values are:
5204 MPEG (restricted) range
5212 Specify output color format.
5214 The accepted values are:
5217 YUV 4:2:0 planar 8-bits
5220 YUV 4:2:0 planar 10-bits
5223 YUV 4:2:0 planar 12-bits
5226 YUV 4:2:2 planar 8-bits
5229 YUV 4:2:2 planar 10-bits
5232 YUV 4:2:2 planar 12-bits
5235 YUV 4:4:4 planar 8-bits
5238 YUV 4:4:4 planar 10-bits
5241 YUV 4:4:4 planar 12-bits
5246 Do a fast conversion, which skips gamma/primary correction. This will take
5247 significantly less CPU, but will be mathematically incorrect. To get output
5248 compatible with that produced by the colormatrix filter, use fast=1.
5251 Specify dithering mode.
5253 The accepted values are:
5259 Floyd-Steinberg dithering
5263 Whitepoint adaptation mode.
5265 The accepted values are:
5268 Bradford whitepoint adaptation
5271 von Kries whitepoint adaptation
5274 identity whitepoint adaptation (i.e. no whitepoint adaptation)
5279 The filter converts the transfer characteristics, color space and color
5280 primaries to the specified user values. The output value, if not specified,
5281 is set to a default value based on the "all" property. If that property is
5282 also not specified, the filter will log an error. The output color range and
5283 format default to the same value as the input color range and format. The
5284 input transfer characteristics, color space, color primaries and color range
5285 should be set on the input data. If any of these are missing, the filter will
5286 log an error and no conversion will take place.
5288 For example to convert the input to SMPTE-240M, use the command:
5290 colorspace=smpte240m
5293 @section convolution
5295 Apply convolution 3x3 or 5x5 filter.
5297 The filter accepts the following options:
5304 Set matrix for each plane.
5305 Matrix is sequence of 9 or 25 signed integers.
5311 Set multiplier for calculated value for each plane.
5317 Set bias for each plane. This value is added to the result of the multiplication.
5318 Useful for making the overall image brighter or darker. Default is 0.0.
5321 @subsection Examples
5327 convolution="0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0"
5333 convolution="1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1/9:1/9:1/9:1/9"
5339 convolution="0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:5:1:1:1:0:128:128:128"
5345 convolution="0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:5:5:5:1:0:128:128:128"
5351 convolution="-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2"
5357 Copy the input source unchanged to the output. This is mainly useful for
5362 Video filtering on GPU using Apple's CoreImage API on OSX.
5364 Hardware acceleration is based on an OpenGL context. Usually, this means it is
5365 processed by video hardware. However, software-based OpenGL implementations
5366 exist which means there is no guarantee for hardware processing. It depends on
5369 There are many filters and image generators provided by Apple that come with a
5370 large variety of options. The filter has to be referenced by its name along
5373 The coreimage filter accepts the following options:
5376 List all available filters and generators along with all their respective
5377 options as well as possible minimum and maximum values along with the default
5384 Specify all filters by their respective name and options.
5385 Use @var{list_filters} to determine all valid filter names and options.
5386 Numerical options are specified by a float value and are automatically clamped
5387 to their respective value range. Vector and color options have to be specified
5388 by a list of space separated float values. Character escaping has to be done.
5389 A special option name @code{default} is available to use default options for a
5392 It is required to specify either @code{default} or at least one of the filter options.
5393 All omitted options are used with their default values.
5394 The syntax of the filter string is as follows:
5396 filter=<NAME>@@<OPTION>=<VALUE>[@@<OPTION>=<VALUE>][@@...][#<NAME>@@<OPTION>=<VALUE>[@@<OPTION>=<VALUE>][@@...]][#...]
5400 Specify a rectangle where the output of the filter chain is copied into the
5401 input image. It is given by a list of space separated float values:
5403 output_rect=x\ y\ width\ height
5405 If not given, the output rectangle equals the dimensions of the input image.
5406 The output rectangle is automatically cropped at the borders of the input
5407 image. Negative values are valid for each component.
5409 output_rect=25\ 25\ 100\ 100
5413 Several filters can be chained for successive processing without GPU-HOST
5414 transfers allowing for fast processing of complex filter chains.
5415 Currently, only filters with zero (generators) or exactly one (filters) input
5416 image and one output image are supported. Also, transition filters are not yet
5419 Some filters generate output images with additional padding depending on the
5420 respective filter kernel. The padding is automatically removed to ensure the
5421 filter output has the same size as the input image.
5423 For image generators, the size of the output image is determined by the
5424 previous output image of the filter chain or the input image of the whole
5425 filterchain, respectively. The generators do not use the pixel information of
5426 this image to generate their output. However, the generated output is
5427 blended onto this image, resulting in partial or complete coverage of the
5430 The @ref{coreimagesrc} video source can be used for generating input images
5431 which are directly fed into the filter chain. By using it, providing input
5432 images by another video source or an input video is not required.
5434 @subsection Examples
5439 List all filters available:
5441 coreimage=list_filters=true
5445 Use the CIBoxBlur filter with default options to blur an image:
5447 coreimage=filter=CIBoxBlur@@default
5451 Use a filter chain with CISepiaTone at default values and CIVignetteEffect with
5452 its center at 100x100 and a radius of 50 pixels:
5454 coreimage=filter=CIBoxBlur@@default#CIVignetteEffect@@inputCenter=100\ 100@@inputRadius=50
5458 Use nullsrc and CIQRCodeGenerator to create a QR code for the FFmpeg homepage,
5459 given as complete and escaped command-line for Apple's standard bash shell:
5461 ffmpeg -f lavfi -i nullsrc=s=100x100,coreimage=filter=CIQRCodeGenerator@@inputMessage=https\\\\\://FFmpeg.org/@@inputCorrectionLevel=H -frames:v 1 QRCode.png
5467 Crop the input video to given dimensions.
5469 It accepts the following parameters:
5473 The width of the output video. It defaults to @code{iw}.
5474 This expression is evaluated only once during the filter
5475 configuration, or when the @samp{w} or @samp{out_w} command is sent.
5478 The height of the output video. It defaults to @code{ih}.
5479 This expression is evaluated only once during the filter
5480 configuration, or when the @samp{h} or @samp{out_h} command is sent.
5483 The horizontal position, in the input video, of the left edge of the output
5484 video. It defaults to @code{(in_w-out_w)/2}.
5485 This expression is evaluated per-frame.
5488 The vertical position, in the input video, of the top edge of the output video.
5489 It defaults to @code{(in_h-out_h)/2}.
5490 This expression is evaluated per-frame.
5493 If set to 1 will force the output display aspect ratio
5494 to be the same of the input, by changing the output sample aspect
5495 ratio. It defaults to 0.
5498 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
5499 expressions containing the following constants:
5504 The computed values for @var{x} and @var{y}. They are evaluated for
5509 The input width and height.
5513 These are the same as @var{in_w} and @var{in_h}.
5517 The output (cropped) width and height.
5521 These are the same as @var{out_w} and @var{out_h}.
5524 same as @var{iw} / @var{ih}
5527 input sample aspect ratio
5530 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
5534 horizontal and vertical chroma subsample values. For example for the
5535 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5538 The number of the input frame, starting from 0.
5541 the position in the file of the input frame, NAN if unknown
5544 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
5548 The expression for @var{out_w} may depend on the value of @var{out_h},
5549 and the expression for @var{out_h} may depend on @var{out_w}, but they
5550 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
5551 evaluated after @var{out_w} and @var{out_h}.
5553 The @var{x} and @var{y} parameters specify the expressions for the
5554 position of the top-left corner of the output (non-cropped) area. They
5555 are evaluated for each frame. If the evaluated value is not valid, it
5556 is approximated to the nearest valid value.
5558 The expression for @var{x} may depend on @var{y}, and the expression
5559 for @var{y} may depend on @var{x}.
5561 @subsection Examples
5565 Crop area with size 100x100 at position (12,34).
5570 Using named options, the example above becomes:
5572 crop=w=100:h=100:x=12:y=34
5576 Crop the central input area with size 100x100:
5582 Crop the central input area with size 2/3 of the input video:
5584 crop=2/3*in_w:2/3*in_h
5588 Crop the input video central square:
5595 Delimit the rectangle with the top-left corner placed at position
5596 100:100 and the right-bottom corner corresponding to the right-bottom
5597 corner of the input image.
5599 crop=in_w-100:in_h-100:100:100
5603 Crop 10 pixels from the left and right borders, and 20 pixels from
5604 the top and bottom borders
5606 crop=in_w-2*10:in_h-2*20
5610 Keep only the bottom right quarter of the input image:
5612 crop=in_w/2:in_h/2:in_w/2:in_h/2
5616 Crop height for getting Greek harmony:
5618 crop=in_w:1/PHI*in_w
5622 Apply trembling effect:
5624 crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(n/10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(n/7)
5628 Apply erratic camera effect depending on timestamp:
5630 crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)"
5634 Set x depending on the value of y:
5636 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
5640 @subsection Commands
5642 This filter supports the following commands:
5648 Set width/height of the output video and the horizontal/vertical position
5650 The command accepts the same syntax of the corresponding option.
5652 If the specified expression is not valid, it is kept at its current
5658 Auto-detect the crop size.
5660 It calculates the necessary cropping parameters and prints the
5661 recommended parameters via the logging system. The detected dimensions
5662 correspond to the non-black area of the input video.
5664 It accepts the following parameters:
5669 Set higher black value threshold, which can be optionally specified
5670 from nothing (0) to everything (255 for 8-bit based formats). An intensity
5671 value greater to the set value is considered non-black. It defaults to 24.
5672 You can also specify a value between 0.0 and 1.0 which will be scaled depending
5673 on the bitdepth of the pixel format.
5676 The value which the width/height should be divisible by. It defaults to
5677 16. The offset is automatically adjusted to center the video. Use 2 to
5678 get only even dimensions (needed for 4:2:2 video). 16 is best when
5679 encoding to most video codecs.
5681 @item reset_count, reset
5682 Set the counter that determines after how many frames cropdetect will
5683 reset the previously detected largest video area and start over to
5684 detect the current optimal crop area. Default value is 0.
5686 This can be useful when channel logos distort the video area. 0
5687 indicates 'never reset', and returns the largest area encountered during
5694 Apply color adjustments using curves.
5696 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
5697 component (red, green and blue) has its values defined by @var{N} key points
5698 tied from each other using a smooth curve. The x-axis represents the pixel
5699 values from the input frame, and the y-axis the new pixel values to be set for
5702 By default, a component curve is defined by the two points @var{(0;0)} and
5703 @var{(1;1)}. This creates a straight line where each original pixel value is
5704 "adjusted" to its own value, which means no change to the image.
5706 The filter allows you to redefine these two points and add some more. A new
5707 curve (using a natural cubic spline interpolation) will be define to pass
5708 smoothly through all these new coordinates. The new defined points needs to be
5709 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
5710 be in the @var{[0;1]} interval. If the computed curves happened to go outside
5711 the vector spaces, the values will be clipped accordingly.
5713 If there is no key point defined in @code{x=0}, the filter will automatically
5714 insert a @var{(0;0)} point. In the same way, if there is no key point defined
5715 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
5717 The filter accepts the following options:
5721 Select one of the available color presets. This option can be used in addition
5722 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
5723 options takes priority on the preset values.
5724 Available presets are:
5727 @item color_negative
5730 @item increase_contrast
5732 @item linear_contrast
5733 @item medium_contrast
5735 @item strong_contrast
5738 Default is @code{none}.
5740 Set the master key points. These points will define a second pass mapping. It
5741 is sometimes called a "luminance" or "value" mapping. It can be used with
5742 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
5743 post-processing LUT.
5745 Set the key points for the red component.
5747 Set the key points for the green component.
5749 Set the key points for the blue component.
5751 Set the key points for all components (not including master).
5752 Can be used in addition to the other key points component
5753 options. In this case, the unset component(s) will fallback on this
5754 @option{all} setting.
5756 Specify a Photoshop curves file (@code{.acv}) to import the settings from.
5759 To avoid some filtergraph syntax conflicts, each key points list need to be
5760 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
5762 @subsection Examples
5766 Increase slightly the middle level of blue:
5768 curves=blue='0.5/0.58'
5774 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
5776 Here we obtain the following coordinates for each components:
5779 @code{(0;0.11) (0.42;0.51) (1;0.95)}
5781 @code{(0;0) (0.50;0.48) (1;1)}
5783 @code{(0;0.22) (0.49;0.44) (1;0.80)}
5787 The previous example can also be achieved with the associated built-in preset:
5789 curves=preset=vintage
5799 Use a Photoshop preset and redefine the points of the green component:
5801 curves=psfile='MyCurvesPresets/purple.acv':green='0.45/0.53'
5807 Video data analysis filter.
5809 This filter shows hexadecimal pixel values of part of video.
5811 The filter accepts the following options:
5815 Set output video size.
5818 Set x offset from where to pick pixels.
5821 Set y offset from where to pick pixels.
5824 Set scope mode, can be one of the following:
5827 Draw hexadecimal pixel values with white color on black background.
5830 Draw hexadecimal pixel values with input video pixel color on black
5834 Draw hexadecimal pixel values on color background picked from input video,
5835 the text color is picked in such way so its always visible.
5839 Draw rows and columns numbers on left and top of video.
5844 Denoise frames using 2D DCT (frequency domain filtering).
5846 This filter is not designed for real time.
5848 The filter accepts the following options:
5852 Set the noise sigma constant.
5854 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
5855 coefficient (absolute value) below this threshold with be dropped.
5857 If you need a more advanced filtering, see @option{expr}.
5859 Default is @code{0}.
5862 Set number overlapping pixels for each block. Since the filter can be slow, you
5863 may want to reduce this value, at the cost of a less effective filter and the
5864 risk of various artefacts.
5866 If the overlapping value doesn't permit processing the whole input width or
5867 height, a warning will be displayed and according borders won't be denoised.
5869 Default value is @var{blocksize}-1, which is the best possible setting.
5872 Set the coefficient factor expression.
5874 For each coefficient of a DCT block, this expression will be evaluated as a
5875 multiplier value for the coefficient.
5877 If this is option is set, the @option{sigma} option will be ignored.
5879 The absolute value of the coefficient can be accessed through the @var{c}
5883 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
5884 @var{blocksize}, which is the width and height of the processed blocks.
5886 The default value is @var{3} (8x8) and can be raised to @var{4} for a
5887 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
5888 on the speed processing. Also, a larger block size does not necessarily means a
5892 @subsection Examples
5894 Apply a denoise with a @option{sigma} of @code{4.5}:
5899 The same operation can be achieved using the expression system:
5901 dctdnoiz=e='gte(c, 4.5*3)'
5904 Violent denoise using a block size of @code{16x16}:
5911 Remove banding artifacts from input video.
5912 It works by replacing banded pixels with average value of referenced pixels.
5914 The filter accepts the following options:
5921 Set banding detection threshold for each plane. Default is 0.02.
5922 Valid range is 0.00003 to 0.5.
5923 If difference between current pixel and reference pixel is less than threshold,
5924 it will be considered as banded.
5927 Banding detection range in pixels. Default is 16. If positive, random number
5928 in range 0 to set value will be used. If negative, exact absolute value
5930 The range defines square of four pixels around current pixel.
5933 Set direction in radians from which four pixel will be compared. If positive,
5934 random direction from 0 to set direction will be picked. If negative, exact of
5935 absolute value will be picked. For example direction 0, -PI or -2*PI radians
5936 will pick only pixels on same row and -PI/2 will pick only pixels on same
5940 If enabled, current pixel is compared with average value of all four
5941 surrounding pixels. The default is enabled. If disabled current pixel is
5942 compared with all four surrounding pixels. The pixel is considered banded
5943 if only all four differences with surrounding pixels are less than threshold.
5949 Drop duplicated frames at regular intervals.
5951 The filter accepts the following options:
5955 Set the number of frames from which one will be dropped. Setting this to
5956 @var{N} means one frame in every batch of @var{N} frames will be dropped.
5957 Default is @code{5}.
5960 Set the threshold for duplicate detection. If the difference metric for a frame
5961 is less than or equal to this value, then it is declared as duplicate. Default
5965 Set scene change threshold. Default is @code{15}.
5969 Set the size of the x and y-axis blocks used during metric calculations.
5970 Larger blocks give better noise suppression, but also give worse detection of
5971 small movements. Must be a power of two. Default is @code{32}.
5974 Mark main input as a pre-processed input and activate clean source input
5975 stream. This allows the input to be pre-processed with various filters to help
5976 the metrics calculation while keeping the frame selection lossless. When set to
5977 @code{1}, the first stream is for the pre-processed input, and the second
5978 stream is the clean source from where the kept frames are chosen. Default is
5982 Set whether or not chroma is considered in the metric calculations. Default is
5988 Apply deflate effect to the video.
5990 This filter replaces the pixel by the local(3x3) average by taking into account
5991 only values lower than the pixel.
5993 It accepts the following options:
6000 Limit the maximum change for each plane, default is 65535.
6001 If 0, plane will remain unchanged.
6006 Remove judder produced by partially interlaced telecined content.
6008 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
6009 source was partially telecined content then the output of @code{pullup,dejudder}
6010 will have a variable frame rate. May change the recorded frame rate of the
6011 container. Aside from that change, this filter will not affect constant frame
6014 The option available in this filter is:
6018 Specify the length of the window over which the judder repeats.
6020 Accepts any integer greater than 1. Useful values are:
6024 If the original was telecined from 24 to 30 fps (Film to NTSC).
6027 If the original was telecined from 25 to 30 fps (PAL to NTSC).
6030 If a mixture of the two.
6033 The default is @samp{4}.
6038 Suppress a TV station logo by a simple interpolation of the surrounding
6039 pixels. Just set a rectangle covering the logo and watch it disappear
6040 (and sometimes something even uglier appear - your mileage may vary).
6042 It accepts the following parameters:
6047 Specify the top left corner coordinates of the logo. They must be
6052 Specify the width and height of the logo to clear. They must be
6056 Specify the thickness of the fuzzy edge of the rectangle (added to
6057 @var{w} and @var{h}). The default value is 1. This option is
6058 deprecated, setting higher values should no longer be necessary and
6062 When set to 1, a green rectangle is drawn on the screen to simplify
6063 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
6064 The default value is 0.
6066 The rectangle is drawn on the outermost pixels which will be (partly)
6067 replaced with interpolated values. The values of the next pixels
6068 immediately outside this rectangle in each direction will be used to
6069 compute the interpolated pixel values inside the rectangle.
6073 @subsection Examples
6077 Set a rectangle covering the area with top left corner coordinates 0,0
6078 and size 100x77, and a band of size 10:
6080 delogo=x=0:y=0:w=100:h=77:band=10
6087 Attempt to fix small changes in horizontal and/or vertical shift. This
6088 filter helps remove camera shake from hand-holding a camera, bumping a
6089 tripod, moving on a vehicle, etc.
6091 The filter accepts the following options:
6099 Specify a rectangular area where to limit the search for motion
6101 If desired the search for motion vectors can be limited to a
6102 rectangular area of the frame defined by its top left corner, width
6103 and height. These parameters have the same meaning as the drawbox
6104 filter which can be used to visualise the position of the bounding
6107 This is useful when simultaneous movement of subjects within the frame
6108 might be confused for camera motion by the motion vector search.
6110 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
6111 then the full frame is used. This allows later options to be set
6112 without specifying the bounding box for the motion vector search.
6114 Default - search the whole frame.
6118 Specify the maximum extent of movement in x and y directions in the
6119 range 0-64 pixels. Default 16.
6122 Specify how to generate pixels to fill blanks at the edge of the
6123 frame. Available values are:
6126 Fill zeroes at blank locations
6128 Original image at blank locations
6130 Extruded edge value at blank locations
6132 Mirrored edge at blank locations
6134 Default value is @samp{mirror}.
6137 Specify the blocksize to use for motion search. Range 4-128 pixels,
6141 Specify the contrast threshold for blocks. Only blocks with more than
6142 the specified contrast (difference between darkest and lightest
6143 pixels) will be considered. Range 1-255, default 125.
6146 Specify the search strategy. Available values are:
6149 Set exhaustive search
6151 Set less exhaustive search.
6153 Default value is @samp{exhaustive}.
6156 If set then a detailed log of the motion search is written to the
6160 If set to 1, specify using OpenCL capabilities, only available if
6161 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
6167 Apply an exact inverse of the telecine operation. It requires a predefined
6168 pattern specified using the pattern option which must be the same as that passed
6169 to the telecine filter.
6171 This filter accepts the following options:
6180 The default value is @code{top}.
6184 A string of numbers representing the pulldown pattern you wish to apply.
6185 The default value is @code{23}.
6188 A number representing position of the first frame with respect to the telecine
6189 pattern. This is to be used if the stream is cut. The default value is @code{0}.
6194 Apply dilation effect to the video.
6196 This filter replaces the pixel by the local(3x3) maximum.
6198 It accepts the following options:
6205 Limit the maximum change for each plane, default is 65535.
6206 If 0, plane will remain unchanged.
6209 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
6212 Flags to local 3x3 coordinates maps like this:
6221 Displace pixels as indicated by second and third input stream.
6223 It takes three input streams and outputs one stream, the first input is the
6224 source, and second and third input are displacement maps.
6226 The second input specifies how much to displace pixels along the
6227 x-axis, while the third input specifies how much to displace pixels
6229 If one of displacement map streams terminates, last frame from that
6230 displacement map will be used.
6232 Note that once generated, displacements maps can be reused over and over again.
6234 A description of the accepted options follows.
6238 Set displace behavior for pixels that are out of range.
6240 Available values are:
6243 Missing pixels are replaced by black pixels.
6246 Adjacent pixels will spread out to replace missing pixels.
6249 Out of range pixels are wrapped so they point to pixels of other side.
6251 Default is @samp{smear}.
6255 @subsection Examples
6259 Add ripple effect to rgb input of video size hd720:
6261 ffmpeg -i INPUT -f lavfi -i nullsrc=s=hd720,lutrgb=128:128:128 -f lavfi -i nullsrc=s=hd720,geq='r=128+30*sin(2*PI*X/400+T):g=128+30*sin(2*PI*X/400+T):b=128+30*sin(2*PI*X/400+T)' -lavfi '[0][1][2]displace' OUTPUT
6265 Add wave effect to rgb input of video size hd720:
6267 ffmpeg -i INPUT -f lavfi -i nullsrc=hd720,geq='r=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T)):g=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T)):b=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T))' -lavfi '[1]split[x][y],[0][x][y]displace' OUTPUT
6273 Draw a colored box on the input image.
6275 It accepts the following parameters:
6280 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
6284 The expressions which specify the width and height of the box; if 0 they are interpreted as
6285 the input width and height. It defaults to 0.
6288 Specify the color of the box to write. For the general syntax of this option,
6289 check the "Color" section in the ffmpeg-utils manual. If the special
6290 value @code{invert} is used, the box edge color is the same as the
6291 video with inverted luma.
6294 The expression which sets the thickness of the box edge. Default value is @code{3}.
6296 See below for the list of accepted constants.
6299 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
6300 following constants:
6304 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
6308 horizontal and vertical chroma subsample values. For example for the
6309 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6313 The input width and height.
6316 The input sample aspect ratio.
6320 The x and y offset coordinates where the box is drawn.
6324 The width and height of the drawn box.
6327 The thickness of the drawn box.
6329 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
6330 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
6334 @subsection Examples
6338 Draw a black box around the edge of the input image:
6344 Draw a box with color red and an opacity of 50%:
6346 drawbox=10:20:200:60:red@@0.5
6349 The previous example can be specified as:
6351 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
6355 Fill the box with pink color:
6357 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
6361 Draw a 2-pixel red 2.40:1 mask:
6363 drawbox=x=-t:y=0.5*(ih-iw/2.4)-t:w=iw+t*2:h=iw/2.4+t*2:t=2:c=red
6367 @section drawgraph, adrawgraph
6369 Draw a graph using input video or audio metadata.
6371 It accepts the following parameters:
6375 Set 1st frame metadata key from which metadata values will be used to draw a graph.
6378 Set 1st foreground color expression.
6381 Set 2nd frame metadata key from which metadata values will be used to draw a graph.
6384 Set 2nd foreground color expression.
6387 Set 3rd frame metadata key from which metadata values will be used to draw a graph.
6390 Set 3rd foreground color expression.
6393 Set 4th frame metadata key from which metadata values will be used to draw a graph.
6396 Set 4th foreground color expression.
6399 Set minimal value of metadata value.
6402 Set maximal value of metadata value.
6405 Set graph background color. Default is white.
6410 Available values for mode is:
6417 Default is @code{line}.
6422 Available values for slide is:
6425 Draw new frame when right border is reached.
6428 Replace old columns with new ones.
6431 Scroll from right to left.
6434 Scroll from left to right.
6437 Default is @code{frame}.
6440 Set size of graph video. For the syntax of this option, check the
6441 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
6442 The default value is @code{900x256}.
6444 The foreground color expressions can use the following variables:
6447 Minimal value of metadata value.
6450 Maximal value of metadata value.
6453 Current metadata key value.
6456 The color is defined as 0xAABBGGRR.
6459 Example using metadata from @ref{signalstats} filter:
6461 signalstats,drawgraph=lavfi.signalstats.YAVG:min=0:max=255
6464 Example using metadata from @ref{ebur128} filter:
6466 ebur128=metadata=1,adrawgraph=lavfi.r128.M:min=-120:max=5
6471 Draw a grid on the input image.
6473 It accepts the following parameters:
6478 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
6482 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
6483 input width and height, respectively, minus @code{thickness}, so image gets
6484 framed. Default to 0.
6487 Specify the color of the grid. For the general syntax of this option,
6488 check the "Color" section in the ffmpeg-utils manual. If the special
6489 value @code{invert} is used, the grid color is the same as the
6490 video with inverted luma.
6493 The expression which sets the thickness of the grid line. Default value is @code{1}.
6495 See below for the list of accepted constants.
6498 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
6499 following constants:
6503 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
6507 horizontal and vertical chroma subsample values. For example for the
6508 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6512 The input grid cell width and height.
6515 The input sample aspect ratio.
6519 The x and y coordinates of some point of grid intersection (meant to configure offset).
6523 The width and height of the drawn cell.
6526 The thickness of the drawn cell.
6528 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
6529 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
6533 @subsection Examples
6537 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
6539 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
6543 Draw a white 3x3 grid with an opacity of 50%:
6545 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
6552 Draw a text string or text from a specified file on top of a video, using the
6553 libfreetype library.
6555 To enable compilation of this filter, you need to configure FFmpeg with
6556 @code{--enable-libfreetype}.
6557 To enable default font fallback and the @var{font} option you need to
6558 configure FFmpeg with @code{--enable-libfontconfig}.
6559 To enable the @var{text_shaping} option, you need to configure FFmpeg with
6560 @code{--enable-libfribidi}.
6564 It accepts the following parameters:
6569 Used to draw a box around text using the background color.
6570 The value must be either 1 (enable) or 0 (disable).
6571 The default value of @var{box} is 0.
6574 Set the width of the border to be drawn around the box using @var{boxcolor}.
6575 The default value of @var{boxborderw} is 0.
6578 The color to be used for drawing box around text. For the syntax of this
6579 option, check the "Color" section in the ffmpeg-utils manual.
6581 The default value of @var{boxcolor} is "white".
6584 Set the width of the border to be drawn around the text using @var{bordercolor}.
6585 The default value of @var{borderw} is 0.
6588 Set the color to be used for drawing border around text. For the syntax of this
6589 option, check the "Color" section in the ffmpeg-utils manual.
6591 The default value of @var{bordercolor} is "black".
6594 Select how the @var{text} is expanded. Can be either @code{none},
6595 @code{strftime} (deprecated) or
6596 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
6600 If true, check and fix text coords to avoid clipping.
6603 The color to be used for drawing fonts. For the syntax of this option, check
6604 the "Color" section in the ffmpeg-utils manual.
6606 The default value of @var{fontcolor} is "black".
6608 @item fontcolor_expr
6609 String which is expanded the same way as @var{text} to obtain dynamic
6610 @var{fontcolor} value. By default this option has empty value and is not
6611 processed. When this option is set, it overrides @var{fontcolor} option.
6614 The font family to be used for drawing text. By default Sans.
6617 The font file to be used for drawing text. The path must be included.
6618 This parameter is mandatory if the fontconfig support is disabled.
6621 This option does not exist, please see the timeline system
6624 Draw the text applying alpha blending. The value can
6625 be either a number between 0.0 and 1.0
6626 The expression accepts the same variables @var{x, y} do.
6627 The default value is 1.
6628 Please see fontcolor_expr
6631 The font size to be used for drawing text.
6632 The default value of @var{fontsize} is 16.
6635 If set to 1, attempt to shape the text (for example, reverse the order of
6636 right-to-left text and join Arabic characters) before drawing it.
6637 Otherwise, just draw the text exactly as given.
6638 By default 1 (if supported).
6641 The flags to be used for loading the fonts.
6643 The flags map the corresponding flags supported by libfreetype, and are
6644 a combination of the following values:
6651 @item vertical_layout
6652 @item force_autohint
6655 @item ignore_global_advance_width
6657 @item ignore_transform
6663 Default value is "default".
6665 For more information consult the documentation for the FT_LOAD_*
6669 The color to be used for drawing a shadow behind the drawn text. For the
6670 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
6672 The default value of @var{shadowcolor} is "black".
6676 The x and y offsets for the text shadow position with respect to the
6677 position of the text. They can be either positive or negative
6678 values. The default value for both is "0".
6681 The starting frame number for the n/frame_num variable. The default value
6685 The size in number of spaces to use for rendering the tab.
6689 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
6690 format. It can be used with or without text parameter. @var{timecode_rate}
6691 option must be specified.
6693 @item timecode_rate, rate, r
6694 Set the timecode frame rate (timecode only).
6697 The text string to be drawn. The text must be a sequence of UTF-8
6699 This parameter is mandatory if no file is specified with the parameter
6703 A text file containing text to be drawn. The text must be a sequence
6704 of UTF-8 encoded characters.
6706 This parameter is mandatory if no text string is specified with the
6707 parameter @var{text}.
6709 If both @var{text} and @var{textfile} are specified, an error is thrown.
6712 If set to 1, the @var{textfile} will be reloaded before each frame.
6713 Be sure to update it atomically, or it may be read partially, or even fail.
6717 The expressions which specify the offsets where text will be drawn
6718 within the video frame. They are relative to the top/left border of the
6721 The default value of @var{x} and @var{y} is "0".
6723 See below for the list of accepted constants and functions.
6726 The parameters for @var{x} and @var{y} are expressions containing the
6727 following constants and functions:
6731 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
6735 horizontal and vertical chroma subsample values. For example for the
6736 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6739 the height of each text line
6747 @item max_glyph_a, ascent
6748 the maximum distance from the baseline to the highest/upper grid
6749 coordinate used to place a glyph outline point, for all the rendered
6751 It is a positive value, due to the grid's orientation with the Y axis
6754 @item max_glyph_d, descent
6755 the maximum distance from the baseline to the lowest grid coordinate
6756 used to place a glyph outline point, for all the rendered glyphs.
6757 This is a negative value, due to the grid's orientation, with the Y axis
6761 maximum glyph height, that is the maximum height for all the glyphs
6762 contained in the rendered text, it is equivalent to @var{ascent} -
6766 maximum glyph width, that is the maximum width for all the glyphs
6767 contained in the rendered text
6770 the number of input frame, starting from 0
6772 @item rand(min, max)
6773 return a random number included between @var{min} and @var{max}
6776 The input sample aspect ratio.
6779 timestamp expressed in seconds, NAN if the input timestamp is unknown
6782 the height of the rendered text
6785 the width of the rendered text
6789 the x and y offset coordinates where the text is drawn.
6791 These parameters allow the @var{x} and @var{y} expressions to refer
6792 each other, so you can for example specify @code{y=x/dar}.
6795 @anchor{drawtext_expansion}
6796 @subsection Text expansion
6798 If @option{expansion} is set to @code{strftime},
6799 the filter recognizes strftime() sequences in the provided text and
6800 expands them accordingly. Check the documentation of strftime(). This
6801 feature is deprecated.
6803 If @option{expansion} is set to @code{none}, the text is printed verbatim.
6805 If @option{expansion} is set to @code{normal} (which is the default),
6806 the following expansion mechanism is used.
6808 The backslash character @samp{\}, followed by any character, always expands to
6809 the second character.
6811 Sequence of the form @code{%@{...@}} are expanded. The text between the
6812 braces is a function name, possibly followed by arguments separated by ':'.
6813 If the arguments contain special characters or delimiters (':' or '@}'),
6814 they should be escaped.
6816 Note that they probably must also be escaped as the value for the
6817 @option{text} option in the filter argument string and as the filter
6818 argument in the filtergraph description, and possibly also for the shell,
6819 that makes up to four levels of escaping; using a text file avoids these
6822 The following functions are available:
6827 The expression evaluation result.
6829 It must take one argument specifying the expression to be evaluated,
6830 which accepts the same constants and functions as the @var{x} and
6831 @var{y} values. Note that not all constants should be used, for
6832 example the text size is not known when evaluating the expression, so
6833 the constants @var{text_w} and @var{text_h} will have an undefined
6836 @item expr_int_format, eif
6837 Evaluate the expression's value and output as formatted integer.
6839 The first argument is the expression to be evaluated, just as for the @var{expr} function.
6840 The second argument specifies the output format. Allowed values are @samp{x},
6841 @samp{X}, @samp{d} and @samp{u}. They are treated exactly as in the
6842 @code{printf} function.
6843 The third parameter is optional and sets the number of positions taken by the output.
6844 It can be used to add padding with zeros from the left.
6847 The time at which the filter is running, expressed in UTC.
6848 It can accept an argument: a strftime() format string.
6851 The time at which the filter is running, expressed in the local time zone.
6852 It can accept an argument: a strftime() format string.
6855 Frame metadata. Takes one or two arguments.
6857 The first argument is mandatory and specifies the metadata key.
6859 The second argument is optional and specifies a default value, used when the
6860 metadata key is not found or empty.
6863 The frame number, starting from 0.
6866 A 1 character description of the current picture type.
6869 The timestamp of the current frame.
6870 It can take up to three arguments.
6872 The first argument is the format of the timestamp; it defaults to @code{flt}
6873 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
6874 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
6875 @code{gmtime} stands for the timestamp of the frame formatted as UTC time;
6876 @code{localtime} stands for the timestamp of the frame formatted as
6877 local time zone time.
6879 The second argument is an offset added to the timestamp.
6881 If the format is set to @code{localtime} or @code{gmtime},
6882 a third argument may be supplied: a strftime() format string.
6883 By default, @var{YYYY-MM-DD HH:MM:SS} format will be used.
6886 @subsection Examples
6890 Draw "Test Text" with font FreeSerif, using the default values for the
6891 optional parameters.
6894 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
6898 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
6899 and y=50 (counting from the top-left corner of the screen), text is
6900 yellow with a red box around it. Both the text and the box have an
6904 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
6905 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
6908 Note that the double quotes are not necessary if spaces are not used
6909 within the parameter list.
6912 Show the text at the center of the video frame:
6914 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h)/2"
6918 Show the text at a random position, switching to a new position every 30 seconds:
6920 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=if(eq(mod(t\,30)\,0)\,rand(0\,(w-text_w))\,x):y=if(eq(mod(t\,30)\,0)\,rand(0\,(h-text_h))\,y)"
6924 Show a text line sliding from right to left in the last row of the video
6925 frame. The file @file{LONG_LINE} is assumed to contain a single line
6928 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
6932 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
6934 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
6938 Draw a single green letter "g", at the center of the input video.
6939 The glyph baseline is placed at half screen height.
6941 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
6945 Show text for 1 second every 3 seconds:
6947 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
6951 Use fontconfig to set the font. Note that the colons need to be escaped.
6953 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
6957 Print the date of a real-time encoding (see strftime(3)):
6959 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
6963 Show text fading in and out (appearing/disappearing):
6966 DS=1.0 # display start
6967 DE=10.0 # display end
6968 FID=1.5 # fade in duration
6969 FOD=5 # fade out duration
6970 ffplay -f lavfi "color,drawtext=text=TEST:fontsize=50:fontfile=FreeSerif.ttf:fontcolor_expr=ff0000%@{eif\\\\: clip(255*(1*between(t\\, $DS + $FID\\, $DE - $FOD) + ((t - $DS)/$FID)*between(t\\, $DS\\, $DS + $FID) + (-(t - $DE)/$FOD)*between(t\\, $DE - $FOD\\, $DE) )\\, 0\\, 255) \\\\: x\\\\: 2 @}"
6975 For more information about libfreetype, check:
6976 @url{http://www.freetype.org/}.
6978 For more information about fontconfig, check:
6979 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
6981 For more information about libfribidi, check:
6982 @url{http://fribidi.org/}.
6986 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
6988 The filter accepts the following options:
6993 Set low and high threshold values used by the Canny thresholding
6996 The high threshold selects the "strong" edge pixels, which are then
6997 connected through 8-connectivity with the "weak" edge pixels selected
6998 by the low threshold.
7000 @var{low} and @var{high} threshold values must be chosen in the range
7001 [0,1], and @var{low} should be lesser or equal to @var{high}.
7003 Default value for @var{low} is @code{20/255}, and default value for @var{high}
7007 Define the drawing mode.
7011 Draw white/gray wires on black background.
7014 Mix the colors to create a paint/cartoon effect.
7017 Default value is @var{wires}.
7020 @subsection Examples
7024 Standard edge detection with custom values for the hysteresis thresholding:
7026 edgedetect=low=0.1:high=0.4
7030 Painting effect without thresholding:
7032 edgedetect=mode=colormix:high=0
7037 Set brightness, contrast, saturation and approximate gamma adjustment.
7039 The filter accepts the following options:
7043 Set the contrast expression. The value must be a float value in range
7044 @code{-2.0} to @code{2.0}. The default value is "1".
7047 Set the brightness expression. The value must be a float value in
7048 range @code{-1.0} to @code{1.0}. The default value is "0".
7051 Set the saturation expression. The value must be a float in
7052 range @code{0.0} to @code{3.0}. The default value is "1".
7055 Set the gamma expression. The value must be a float in range
7056 @code{0.1} to @code{10.0}. The default value is "1".
7059 Set the gamma expression for red. The value must be a float in
7060 range @code{0.1} to @code{10.0}. The default value is "1".
7063 Set the gamma expression for green. The value must be a float in range
7064 @code{0.1} to @code{10.0}. The default value is "1".
7067 Set the gamma expression for blue. The value must be a float in range
7068 @code{0.1} to @code{10.0}. The default value is "1".
7071 Set the gamma weight expression. It can be used to reduce the effect
7072 of a high gamma value on bright image areas, e.g. keep them from
7073 getting overamplified and just plain white. The value must be a float
7074 in range @code{0.0} to @code{1.0}. A value of @code{0.0} turns the
7075 gamma correction all the way down while @code{1.0} leaves it at its
7076 full strength. Default is "1".
7079 Set when the expressions for brightness, contrast, saturation and
7080 gamma expressions are evaluated.
7082 It accepts the following values:
7085 only evaluate expressions once during the filter initialization or
7086 when a command is processed
7089 evaluate expressions for each incoming frame
7092 Default value is @samp{init}.
7095 The expressions accept the following parameters:
7098 frame count of the input frame starting from 0
7101 byte position of the corresponding packet in the input file, NAN if
7105 frame rate of the input video, NAN if the input frame rate is unknown
7108 timestamp expressed in seconds, NAN if the input timestamp is unknown
7111 @subsection Commands
7112 The filter supports the following commands:
7116 Set the contrast expression.
7119 Set the brightness expression.
7122 Set the saturation expression.
7125 Set the gamma expression.
7128 Set the gamma_r expression.
7131 Set gamma_g expression.
7134 Set gamma_b expression.
7137 Set gamma_weight expression.
7139 The command accepts the same syntax of the corresponding option.
7141 If the specified expression is not valid, it is kept at its current
7148 Apply erosion effect to the video.
7150 This filter replaces the pixel by the local(3x3) minimum.
7152 It accepts the following options:
7159 Limit the maximum change for each plane, default is 65535.
7160 If 0, plane will remain unchanged.
7163 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
7166 Flags to local 3x3 coordinates maps like this:
7173 @section extractplanes
7175 Extract color channel components from input video stream into
7176 separate grayscale video streams.
7178 The filter accepts the following option:
7182 Set plane(s) to extract.
7184 Available values for planes are:
7195 Choosing planes not available in the input will result in an error.
7196 That means you cannot select @code{r}, @code{g}, @code{b} planes
7197 with @code{y}, @code{u}, @code{v} planes at same time.
7200 @subsection Examples
7204 Extract luma, u and v color channel component from input video frame
7205 into 3 grayscale outputs:
7207 ffmpeg -i video.avi -filter_complex 'extractplanes=y+u+v[y][u][v]' -map '[y]' y.avi -map '[u]' u.avi -map '[v]' v.avi
7213 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
7215 For each input image, the filter will compute the optimal mapping from
7216 the input to the output given the codebook length, that is the number
7217 of distinct output colors.
7219 This filter accepts the following options.
7222 @item codebook_length, l
7223 Set codebook length. The value must be a positive integer, and
7224 represents the number of distinct output colors. Default value is 256.
7227 Set the maximum number of iterations to apply for computing the optimal
7228 mapping. The higher the value the better the result and the higher the
7229 computation time. Default value is 1.
7232 Set a random seed, must be an integer included between 0 and
7233 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
7234 will try to use a good random seed on a best effort basis.
7237 Set pal8 output pixel format. This option does not work with codebook
7238 length greater than 256.
7243 Apply a fade-in/out effect to the input video.
7245 It accepts the following parameters:
7249 The effect type can be either "in" for a fade-in, or "out" for a fade-out
7251 Default is @code{in}.
7253 @item start_frame, s
7254 Specify the number of the frame to start applying the fade
7255 effect at. Default is 0.
7258 The number of frames that the fade effect lasts. At the end of the
7259 fade-in effect, the output video will have the same intensity as the input video.
7260 At the end of the fade-out transition, the output video will be filled with the
7261 selected @option{color}.
7265 If set to 1, fade only alpha channel, if one exists on the input.
7268 @item start_time, st
7269 Specify the timestamp (in seconds) of the frame to start to apply the fade
7270 effect. If both start_frame and start_time are specified, the fade will start at
7271 whichever comes last. Default is 0.
7274 The number of seconds for which the fade effect has to last. At the end of the
7275 fade-in effect the output video will have the same intensity as the input video,
7276 at the end of the fade-out transition the output video will be filled with the
7277 selected @option{color}.
7278 If both duration and nb_frames are specified, duration is used. Default is 0
7279 (nb_frames is used by default).
7282 Specify the color of the fade. Default is "black".
7285 @subsection Examples
7289 Fade in the first 30 frames of video:
7294 The command above is equivalent to:
7300 Fade out the last 45 frames of a 200-frame video:
7303 fade=type=out:start_frame=155:nb_frames=45
7307 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
7309 fade=in:0:25, fade=out:975:25
7313 Make the first 5 frames yellow, then fade in from frame 5-24:
7315 fade=in:5:20:color=yellow
7319 Fade in alpha over first 25 frames of video:
7321 fade=in:0:25:alpha=1
7325 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
7327 fade=t=in:st=5.5:d=0.5
7333 Apply arbitrary expressions to samples in frequency domain
7337 Adjust the dc value (gain) of the luma plane of the image. The filter
7338 accepts an integer value in range @code{0} to @code{1000}. The default
7339 value is set to @code{0}.
7342 Adjust the dc value (gain) of the 1st chroma plane of the image. The
7343 filter accepts an integer value in range @code{0} to @code{1000}. The
7344 default value is set to @code{0}.
7347 Adjust the dc value (gain) of the 2nd chroma plane of the image. The
7348 filter accepts an integer value in range @code{0} to @code{1000}. The
7349 default value is set to @code{0}.
7352 Set the frequency domain weight expression for the luma plane.
7355 Set the frequency domain weight expression for the 1st chroma plane.
7358 Set the frequency domain weight expression for the 2nd chroma plane.
7360 The filter accepts the following variables:
7363 The coordinates of the current sample.
7367 The width and height of the image.
7370 @subsection Examples
7376 fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
7382 fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
7388 fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
7394 fftfilt=dc_Y=0:weight_Y='exp(-4 * ((Y+X)/(W+H)))'
7401 Extract a single field from an interlaced image using stride
7402 arithmetic to avoid wasting CPU time. The output frames are marked as
7405 The filter accepts the following options:
7409 Specify whether to extract the top (if the value is @code{0} or
7410 @code{top}) or the bottom field (if the value is @code{1} or
7416 Create new frames by copying the top and bottom fields from surrounding frames
7417 supplied as numbers by the hint file.
7421 Set file containing hints: absolute/relative frame numbers.
7423 There must be one line for each frame in a clip. Each line must contain two
7424 numbers separated by the comma, optionally followed by @code{-} or @code{+}.
7425 Numbers supplied on each line of file can not be out of [N-1,N+1] where N
7426 is current frame number for @code{absolute} mode or out of [-1, 1] range
7427 for @code{relative} mode. First number tells from which frame to pick up top
7428 field and second number tells from which frame to pick up bottom field.
7430 If optionally followed by @code{+} output frame will be marked as interlaced,
7431 else if followed by @code{-} output frame will be marked as progressive, else
7432 it will be marked same as input frame.
7433 If line starts with @code{#} or @code{;} that line is skipped.
7436 Can be item @code{absolute} or @code{relative}. Default is @code{absolute}.
7439 Example of first several lines of @code{hint} file for @code{relative} mode:
7442 1,0 - # second frame, use third's frame top field and second's frame bottom field
7443 1,0 - # third frame, use fourth's frame top field and third's frame bottom field
7460 Field matching filter for inverse telecine. It is meant to reconstruct the
7461 progressive frames from a telecined stream. The filter does not drop duplicated
7462 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
7463 followed by a decimation filter such as @ref{decimate} in the filtergraph.
7465 The separation of the field matching and the decimation is notably motivated by
7466 the possibility of inserting a de-interlacing filter fallback between the two.
7467 If the source has mixed telecined and real interlaced content,
7468 @code{fieldmatch} will not be able to match fields for the interlaced parts.
7469 But these remaining combed frames will be marked as interlaced, and thus can be
7470 de-interlaced by a later filter such as @ref{yadif} before decimation.
7472 In addition to the various configuration options, @code{fieldmatch} can take an
7473 optional second stream, activated through the @option{ppsrc} option. If
7474 enabled, the frames reconstruction will be based on the fields and frames from
7475 this second stream. This allows the first input to be pre-processed in order to
7476 help the various algorithms of the filter, while keeping the output lossless
7477 (assuming the fields are matched properly). Typically, a field-aware denoiser,
7478 or brightness/contrast adjustments can help.
7480 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
7481 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
7482 which @code{fieldmatch} is based on. While the semantic and usage are very
7483 close, some behaviour and options names can differ.
7485 The @ref{decimate} filter currently only works for constant frame rate input.
7486 If your input has mixed telecined (30fps) and progressive content with a lower
7487 framerate like 24fps use the following filterchain to produce the necessary cfr
7488 stream: @code{dejudder,fps=30000/1001,fieldmatch,decimate}.
7490 The filter accepts the following options:
7494 Specify the assumed field order of the input stream. Available values are:
7498 Auto detect parity (use FFmpeg's internal parity value).
7500 Assume bottom field first.
7502 Assume top field first.
7505 Note that it is sometimes recommended not to trust the parity announced by the
7508 Default value is @var{auto}.
7511 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
7512 sense that it won't risk creating jerkiness due to duplicate frames when
7513 possible, but if there are bad edits or blended fields it will end up
7514 outputting combed frames when a good match might actually exist. On the other
7515 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
7516 but will almost always find a good frame if there is one. The other values are
7517 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
7518 jerkiness and creating duplicate frames versus finding good matches in sections
7519 with bad edits, orphaned fields, blended fields, etc.
7521 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
7523 Available values are:
7527 2-way matching (p/c)
7529 2-way matching, and trying 3rd match if still combed (p/c + n)
7531 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
7533 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
7534 still combed (p/c + n + u/b)
7536 3-way matching (p/c/n)
7538 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
7539 detected as combed (p/c/n + u/b)
7542 The parenthesis at the end indicate the matches that would be used for that
7543 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
7546 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
7549 Default value is @var{pc_n}.
7552 Mark the main input stream as a pre-processed input, and enable the secondary
7553 input stream as the clean source to pick the fields from. See the filter
7554 introduction for more details. It is similar to the @option{clip2} feature from
7557 Default value is @code{0} (disabled).
7560 Set the field to match from. It is recommended to set this to the same value as
7561 @option{order} unless you experience matching failures with that setting. In
7562 certain circumstances changing the field that is used to match from can have a
7563 large impact on matching performance. Available values are:
7567 Automatic (same value as @option{order}).
7569 Match from the bottom field.
7571 Match from the top field.
7574 Default value is @var{auto}.
7577 Set whether or not chroma is included during the match comparisons. In most
7578 cases it is recommended to leave this enabled. You should set this to @code{0}
7579 only if your clip has bad chroma problems such as heavy rainbowing or other
7580 artifacts. Setting this to @code{0} could also be used to speed things up at
7581 the cost of some accuracy.
7583 Default value is @code{1}.
7587 These define an exclusion band which excludes the lines between @option{y0} and
7588 @option{y1} from being included in the field matching decision. An exclusion
7589 band can be used to ignore subtitles, a logo, or other things that may
7590 interfere with the matching. @option{y0} sets the starting scan line and
7591 @option{y1} sets the ending line; all lines in between @option{y0} and
7592 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
7593 @option{y0} and @option{y1} to the same value will disable the feature.
7594 @option{y0} and @option{y1} defaults to @code{0}.
7597 Set the scene change detection threshold as a percentage of maximum change on
7598 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
7599 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
7600 @option{scthresh} is @code{[0.0, 100.0]}.
7602 Default value is @code{12.0}.
7605 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
7606 account the combed scores of matches when deciding what match to use as the
7607 final match. Available values are:
7611 No final matching based on combed scores.
7613 Combed scores are only used when a scene change is detected.
7615 Use combed scores all the time.
7618 Default is @var{sc}.
7621 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
7622 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
7623 Available values are:
7627 No forced calculation.
7629 Force p/c/n calculations.
7631 Force p/c/n/u/b calculations.
7634 Default value is @var{none}.
7637 This is the area combing threshold used for combed frame detection. This
7638 essentially controls how "strong" or "visible" combing must be to be detected.
7639 Larger values mean combing must be more visible and smaller values mean combing
7640 can be less visible or strong and still be detected. Valid settings are from
7641 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
7642 be detected as combed). This is basically a pixel difference value. A good
7643 range is @code{[8, 12]}.
7645 Default value is @code{9}.
7648 Sets whether or not chroma is considered in the combed frame decision. Only
7649 disable this if your source has chroma problems (rainbowing, etc.) that are
7650 causing problems for the combed frame detection with chroma enabled. Actually,
7651 using @option{chroma}=@var{0} is usually more reliable, except for the case
7652 where there is chroma only combing in the source.
7654 Default value is @code{0}.
7658 Respectively set the x-axis and y-axis size of the window used during combed
7659 frame detection. This has to do with the size of the area in which
7660 @option{combpel} pixels are required to be detected as combed for a frame to be
7661 declared combed. See the @option{combpel} parameter description for more info.
7662 Possible values are any number that is a power of 2 starting at 4 and going up
7665 Default value is @code{16}.
7668 The number of combed pixels inside any of the @option{blocky} by
7669 @option{blockx} size blocks on the frame for the frame to be detected as
7670 combed. While @option{cthresh} controls how "visible" the combing must be, this
7671 setting controls "how much" combing there must be in any localized area (a
7672 window defined by the @option{blockx} and @option{blocky} settings) on the
7673 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
7674 which point no frames will ever be detected as combed). This setting is known
7675 as @option{MI} in TFM/VFM vocabulary.
7677 Default value is @code{80}.
7680 @anchor{p/c/n/u/b meaning}
7681 @subsection p/c/n/u/b meaning
7683 @subsubsection p/c/n
7685 We assume the following telecined stream:
7688 Top fields: 1 2 2 3 4
7689 Bottom fields: 1 2 3 4 4
7692 The numbers correspond to the progressive frame the fields relate to. Here, the
7693 first two frames are progressive, the 3rd and 4th are combed, and so on.
7695 When @code{fieldmatch} is configured to run a matching from bottom
7696 (@option{field}=@var{bottom}) this is how this input stream get transformed:
7701 B 1 2 3 4 4 <-- matching reference
7710 As a result of the field matching, we can see that some frames get duplicated.
7711 To perform a complete inverse telecine, you need to rely on a decimation filter
7712 after this operation. See for instance the @ref{decimate} filter.
7714 The same operation now matching from top fields (@option{field}=@var{top})
7719 T 1 2 2 3 4 <-- matching reference
7729 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
7730 basically, they refer to the frame and field of the opposite parity:
7733 @item @var{p} matches the field of the opposite parity in the previous frame
7734 @item @var{c} matches the field of the opposite parity in the current frame
7735 @item @var{n} matches the field of the opposite parity in the next frame
7740 The @var{u} and @var{b} matching are a bit special in the sense that they match
7741 from the opposite parity flag. In the following examples, we assume that we are
7742 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
7743 'x' is placed above and below each matched fields.
7745 With bottom matching (@option{field}=@var{bottom}):
7750 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
7751 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
7759 With top matching (@option{field}=@var{top}):
7764 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
7765 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
7773 @subsection Examples
7775 Simple IVTC of a top field first telecined stream:
7777 fieldmatch=order=tff:combmatch=none, decimate
7780 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
7782 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
7787 Transform the field order of the input video.
7789 It accepts the following parameters:
7794 The output field order. Valid values are @var{tff} for top field first or @var{bff}
7795 for bottom field first.
7798 The default value is @samp{tff}.
7800 The transformation is done by shifting the picture content up or down
7801 by one line, and filling the remaining line with appropriate picture content.
7802 This method is consistent with most broadcast field order converters.
7804 If the input video is not flagged as being interlaced, or it is already
7805 flagged as being of the required output field order, then this filter does
7806 not alter the incoming video.
7808 It is very useful when converting to or from PAL DV material,
7809 which is bottom field first.
7813 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
7816 @section fifo, afifo
7818 Buffer input images and send them when they are requested.
7820 It is mainly useful when auto-inserted by the libavfilter
7823 It does not take parameters.
7827 Find a rectangular object
7829 It accepts the following options:
7833 Filepath of the object image, needs to be in gray8.
7836 Detection threshold, default is 0.5.
7839 Number of mipmaps, default is 3.
7841 @item xmin, ymin, xmax, ymax
7842 Specifies the rectangle in which to search.
7845 @subsection Examples
7849 Generate a representative palette of a given video using @command{ffmpeg}:
7851 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
7857 Cover a rectangular object
7859 It accepts the following options:
7863 Filepath of the optional cover image, needs to be in yuv420.
7868 It accepts the following values:
7871 cover it by the supplied image
7873 cover it by interpolating the surrounding pixels
7876 Default value is @var{blur}.
7879 @subsection Examples
7883 Generate a representative palette of a given video using @command{ffmpeg}:
7885 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
7892 Convert the input video to one of the specified pixel formats.
7893 Libavfilter will try to pick one that is suitable as input to
7896 It accepts the following parameters:
7900 A '|'-separated list of pixel format names, such as
7901 "pix_fmts=yuv420p|monow|rgb24".
7905 @subsection Examples
7909 Convert the input video to the @var{yuv420p} format
7911 format=pix_fmts=yuv420p
7914 Convert the input video to any of the formats in the list
7916 format=pix_fmts=yuv420p|yuv444p|yuv410p
7923 Convert the video to specified constant frame rate by duplicating or dropping
7924 frames as necessary.
7926 It accepts the following parameters:
7930 The desired output frame rate. The default is @code{25}.
7935 Possible values are:
7938 zero round towards 0
7942 round towards -infinity
7944 round towards +infinity
7948 The default is @code{near}.
7951 Assume the first PTS should be the given value, in seconds. This allows for
7952 padding/trimming at the start of stream. By default, no assumption is made
7953 about the first frame's expected PTS, so no padding or trimming is done.
7954 For example, this could be set to 0 to pad the beginning with duplicates of
7955 the first frame if a video stream starts after the audio stream or to trim any
7956 frames with a negative PTS.
7960 Alternatively, the options can be specified as a flat string:
7961 @var{fps}[:@var{round}].
7963 See also the @ref{setpts} filter.
7965 @subsection Examples
7969 A typical usage in order to set the fps to 25:
7975 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
7977 fps=fps=film:round=near
7983 Pack two different video streams into a stereoscopic video, setting proper
7984 metadata on supported codecs. The two views should have the same size and
7985 framerate and processing will stop when the shorter video ends. Please note
7986 that you may conveniently adjust view properties with the @ref{scale} and
7989 It accepts the following parameters:
7993 The desired packing format. Supported values are:
7998 The views are next to each other (default).
8001 The views are on top of each other.
8004 The views are packed by line.
8007 The views are packed by column.
8010 The views are temporally interleaved.
8019 # Convert left and right views into a frame-sequential video
8020 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
8022 # Convert views into a side-by-side video with the same output resolution as the input
8023 ffmpeg -i LEFT -i RIGHT -filter_complex [0:v]scale=w=iw/2[left],[1:v]scale=w=iw/2[right],[left][right]framepack=sbs OUTPUT
8028 Change the frame rate by interpolating new video output frames from the source
8031 This filter is not designed to function correctly with interlaced media. If
8032 you wish to change the frame rate of interlaced media then you are required
8033 to deinterlace before this filter and re-interlace after this filter.
8035 A description of the accepted options follows.
8039 Specify the output frames per second. This option can also be specified
8040 as a value alone. The default is @code{50}.
8043 Specify the start of a range where the output frame will be created as a
8044 linear interpolation of two frames. The range is [@code{0}-@code{255}],
8045 the default is @code{15}.
8048 Specify the end of a range where the output frame will be created as a
8049 linear interpolation of two frames. The range is [@code{0}-@code{255}],
8050 the default is @code{240}.
8053 Specify the level at which a scene change is detected as a value between
8054 0 and 100 to indicate a new scene; a low value reflects a low
8055 probability for the current frame to introduce a new scene, while a higher
8056 value means the current frame is more likely to be one.
8057 The default is @code{7}.
8060 Specify flags influencing the filter process.
8062 Available value for @var{flags} is:
8065 @item scene_change_detect, scd
8066 Enable scene change detection using the value of the option @var{scene}.
8067 This flag is enabled by default.
8073 Select one frame every N-th frame.
8075 This filter accepts the following option:
8078 Select frame after every @code{step} frames.
8079 Allowed values are positive integers higher than 0. Default value is @code{1}.
8085 Apply a frei0r effect to the input video.
8087 To enable the compilation of this filter, you need to install the frei0r
8088 header and configure FFmpeg with @code{--enable-frei0r}.
8090 It accepts the following parameters:
8095 The name of the frei0r effect to load. If the environment variable
8096 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
8097 directories specified by the colon-separated list in @env{FREIOR_PATH}.
8098 Otherwise, the standard frei0r paths are searched, in this order:
8099 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
8100 @file{/usr/lib/frei0r-1/}.
8103 A '|'-separated list of parameters to pass to the frei0r effect.
8107 A frei0r effect parameter can be a boolean (its value is either
8108 "y" or "n"), a double, a color (specified as
8109 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
8110 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
8111 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
8112 @var{X} and @var{Y} are floating point numbers) and/or a string.
8114 The number and types of parameters depend on the loaded effect. If an
8115 effect parameter is not specified, the default value is set.
8117 @subsection Examples
8121 Apply the distort0r effect, setting the first two double parameters:
8123 frei0r=filter_name=distort0r:filter_params=0.5|0.01
8127 Apply the colordistance effect, taking a color as the first parameter:
8129 frei0r=colordistance:0.2/0.3/0.4
8130 frei0r=colordistance:violet
8131 frei0r=colordistance:0x112233
8135 Apply the perspective effect, specifying the top left and top right image
8138 frei0r=perspective:0.2/0.2|0.8/0.2
8142 For more information, see
8143 @url{http://frei0r.dyne.org}
8147 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
8149 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
8150 processing filter, one of them is performed once per block, not per pixel.
8151 This allows for much higher speed.
8153 The filter accepts the following options:
8157 Set quality. This option defines the number of levels for averaging. It accepts
8158 an integer in the range 4-5. Default value is @code{4}.
8161 Force a constant quantization parameter. It accepts an integer in range 0-63.
8162 If not set, the filter will use the QP from the video stream (if available).
8165 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
8166 more details but also more artifacts, while higher values make the image smoother
8167 but also blurrier. Default value is @code{0} − PSNR optimal.
8170 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8171 option may cause flicker since the B-Frames have often larger QP. Default is
8172 @code{0} (not enabled).
8178 The filter accepts the following options:
8182 Set the luminance expression.
8184 Set the chrominance blue expression.
8186 Set the chrominance red expression.
8188 Set the alpha expression.
8190 Set the red expression.
8192 Set the green expression.
8194 Set the blue expression.
8197 The colorspace is selected according to the specified options. If one
8198 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
8199 options is specified, the filter will automatically select a YCbCr
8200 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
8201 @option{blue_expr} options is specified, it will select an RGB
8204 If one of the chrominance expression is not defined, it falls back on the other
8205 one. If no alpha expression is specified it will evaluate to opaque value.
8206 If none of chrominance expressions are specified, they will evaluate
8207 to the luminance expression.
8209 The expressions can use the following variables and functions:
8213 The sequential number of the filtered frame, starting from @code{0}.
8217 The coordinates of the current sample.
8221 The width and height of the image.
8225 Width and height scale depending on the currently filtered plane. It is the
8226 ratio between the corresponding luma plane number of pixels and the current
8227 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
8228 @code{0.5,0.5} for chroma planes.
8231 Time of the current frame, expressed in seconds.
8234 Return the value of the pixel at location (@var{x},@var{y}) of the current
8238 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
8242 Return the value of the pixel at location (@var{x},@var{y}) of the
8243 blue-difference chroma plane. Return 0 if there is no such plane.
8246 Return the value of the pixel at location (@var{x},@var{y}) of the
8247 red-difference chroma plane. Return 0 if there is no such plane.
8252 Return the value of the pixel at location (@var{x},@var{y}) of the
8253 red/green/blue component. Return 0 if there is no such component.
8256 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
8257 plane. Return 0 if there is no such plane.
8260 For functions, if @var{x} and @var{y} are outside the area, the value will be
8261 automatically clipped to the closer edge.
8263 @subsection Examples
8267 Flip the image horizontally:
8273 Generate a bidimensional sine wave, with angle @code{PI/3} and a
8274 wavelength of 100 pixels:
8276 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
8280 Generate a fancy enigmatic moving light:
8282 nullsrc=s=256x256,geq=random(1)/hypot(X-cos(N*0.07)*W/2-W/2\,Y-sin(N*0.09)*H/2-H/2)^2*1000000*sin(N*0.02):128:128
8286 Generate a quick emboss effect:
8288 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
8292 Modify RGB components depending on pixel position:
8294 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
8298 Create a radial gradient that is the same size as the input (also see
8299 the @ref{vignette} filter):
8301 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
8307 Fix the banding artifacts that are sometimes introduced into nearly flat
8308 regions by truncation to 8-bit color depth.
8309 Interpolate the gradients that should go where the bands are, and
8312 It is designed for playback only. Do not use it prior to
8313 lossy compression, because compression tends to lose the dither and
8314 bring back the bands.
8316 It accepts the following parameters:
8321 The maximum amount by which the filter will change any one pixel. This is also
8322 the threshold for detecting nearly flat regions. Acceptable values range from
8323 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
8327 The neighborhood to fit the gradient to. A larger radius makes for smoother
8328 gradients, but also prevents the filter from modifying the pixels near detailed
8329 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
8330 values will be clipped to the valid range.
8334 Alternatively, the options can be specified as a flat string:
8335 @var{strength}[:@var{radius}]
8337 @subsection Examples
8341 Apply the filter with a @code{3.5} strength and radius of @code{8}:
8347 Specify radius, omitting the strength (which will fall-back to the default
8358 Apply a Hald CLUT to a video stream.
8360 First input is the video stream to process, and second one is the Hald CLUT.
8361 The Hald CLUT input can be a simple picture or a complete video stream.
8363 The filter accepts the following options:
8367 Force termination when the shortest input terminates. Default is @code{0}.
8369 Continue applying the last CLUT after the end of the stream. A value of
8370 @code{0} disable the filter after the last frame of the CLUT is reached.
8371 Default is @code{1}.
8374 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
8375 filters share the same internals).
8377 More information about the Hald CLUT can be found on Eskil Steenberg's website
8378 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
8380 @subsection Workflow examples
8382 @subsubsection Hald CLUT video stream
8384 Generate an identity Hald CLUT stream altered with various effects:
8386 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "hue=H=2*PI*t:s=sin(2*PI*t)+1, curves=cross_process" -t 10 -c:v ffv1 clut.nut
8389 Note: make sure you use a lossless codec.
8391 Then use it with @code{haldclut} to apply it on some random stream:
8393 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
8396 The Hald CLUT will be applied to the 10 first seconds (duration of
8397 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
8398 to the remaining frames of the @code{mandelbrot} stream.
8400 @subsubsection Hald CLUT with preview
8402 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
8403 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
8404 biggest possible square starting at the top left of the picture. The remaining
8405 padding pixels (bottom or right) will be ignored. This area can be used to add
8406 a preview of the Hald CLUT.
8408 Typically, the following generated Hald CLUT will be supported by the
8409 @code{haldclut} filter:
8412 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
8413 pad=iw+320 [padded_clut];
8414 smptebars=s=320x256, split [a][b];
8415 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
8416 [main][b] overlay=W-320" -frames:v 1 clut.png
8419 It contains the original and a preview of the effect of the CLUT: SMPTE color
8420 bars are displayed on the right-top, and below the same color bars processed by
8423 Then, the effect of this Hald CLUT can be visualized with:
8425 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
8430 Decodes high definition audio cd data. 16-Bit PCM stream containing hdcd flags
8431 is converted to 20-bit PCM stream.
8435 Flip the input video horizontally.
8437 For example, to horizontally flip the input video with @command{ffmpeg}:
8439 ffmpeg -i in.avi -vf "hflip" out.avi
8443 This filter applies a global color histogram equalization on a
8446 It can be used to correct video that has a compressed range of pixel
8447 intensities. The filter redistributes the pixel intensities to
8448 equalize their distribution across the intensity range. It may be
8449 viewed as an "automatically adjusting contrast filter". This filter is
8450 useful only for correcting degraded or poorly captured source
8453 The filter accepts the following options:
8457 Determine the amount of equalization to be applied. As the strength
8458 is reduced, the distribution of pixel intensities more-and-more
8459 approaches that of the input frame. The value must be a float number
8460 in the range [0,1] and defaults to 0.200.
8463 Set the maximum intensity that can generated and scale the output
8464 values appropriately. The strength should be set as desired and then
8465 the intensity can be limited if needed to avoid washing-out. The value
8466 must be a float number in the range [0,1] and defaults to 0.210.
8469 Set the antibanding level. If enabled the filter will randomly vary
8470 the luminance of output pixels by a small amount to avoid banding of
8471 the histogram. Possible values are @code{none}, @code{weak} or
8472 @code{strong}. It defaults to @code{none}.
8477 Compute and draw a color distribution histogram for the input video.
8479 The computed histogram is a representation of the color component
8480 distribution in an image.
8482 Standard histogram displays the color components distribution in an image.
8483 Displays color graph for each color component. Shows distribution of
8484 the Y, U, V, A or R, G, B components, depending on input format, in the
8485 current frame. Below each graph a color component scale meter is shown.
8487 The filter accepts the following options:
8491 Set height of level. Default value is @code{200}.
8492 Allowed range is [50, 2048].
8495 Set height of color scale. Default value is @code{12}.
8496 Allowed range is [0, 40].
8500 It accepts the following values:
8503 Per color component graphs are placed below each other.
8506 Presents information identical to that in the @code{parade}, except
8507 that the graphs representing color components are superimposed directly
8510 Default is @code{parade}.
8513 Set mode. Can be either @code{linear}, or @code{logarithmic}.
8514 Default is @code{linear}.
8517 Set what color components to display.
8518 Default is @code{7}.
8521 @subsection Examples
8526 Calculate and draw histogram:
8528 ffplay -i input -vf histogram
8536 This is a high precision/quality 3d denoise filter. It aims to reduce
8537 image noise, producing smooth images and making still images really
8538 still. It should enhance compressibility.
8540 It accepts the following optional parameters:
8544 A non-negative floating point number which specifies spatial luma strength.
8547 @item chroma_spatial
8548 A non-negative floating point number which specifies spatial chroma strength.
8549 It defaults to 3.0*@var{luma_spatial}/4.0.
8552 A floating point number which specifies luma temporal strength. It defaults to
8553 6.0*@var{luma_spatial}/4.0.
8556 A floating point number which specifies chroma temporal strength. It defaults to
8557 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
8560 @anchor{hwupload_cuda}
8561 @section hwupload_cuda
8563 Upload system memory frames to a CUDA device.
8565 It accepts the following optional parameters:
8569 The number of the CUDA device to use
8574 Apply a high-quality magnification filter designed for pixel art. This filter
8575 was originally created by Maxim Stepin.
8577 It accepts the following option:
8581 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
8582 @code{hq3x} and @code{4} for @code{hq4x}.
8583 Default is @code{3}.
8587 Stack input videos horizontally.
8589 All streams must be of same pixel format and of same height.
8591 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
8592 to create same output.
8594 The filter accept the following option:
8598 Set number of input streams. Default is 2.
8601 If set to 1, force the output to terminate when the shortest input
8602 terminates. Default value is 0.
8607 Modify the hue and/or the saturation of the input.
8609 It accepts the following parameters:
8613 Specify the hue angle as a number of degrees. It accepts an expression,
8614 and defaults to "0".
8617 Specify the saturation in the [-10,10] range. It accepts an expression and
8621 Specify the hue angle as a number of radians. It accepts an
8622 expression, and defaults to "0".
8625 Specify the brightness in the [-10,10] range. It accepts an expression and
8629 @option{h} and @option{H} are mutually exclusive, and can't be
8630 specified at the same time.
8632 The @option{b}, @option{h}, @option{H} and @option{s} option values are
8633 expressions containing the following constants:
8637 frame count of the input frame starting from 0
8640 presentation timestamp of the input frame expressed in time base units
8643 frame rate of the input video, NAN if the input frame rate is unknown
8646 timestamp expressed in seconds, NAN if the input timestamp is unknown
8649 time base of the input video
8652 @subsection Examples
8656 Set the hue to 90 degrees and the saturation to 1.0:
8662 Same command but expressing the hue in radians:
8668 Rotate hue and make the saturation swing between 0
8669 and 2 over a period of 1 second:
8671 hue="H=2*PI*t: s=sin(2*PI*t)+1"
8675 Apply a 3 seconds saturation fade-in effect starting at 0:
8680 The general fade-in expression can be written as:
8682 hue="s=min(0\, max((t-START)/DURATION\, 1))"
8686 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
8688 hue="s=max(0\, min(1\, (8-t)/3))"
8691 The general fade-out expression can be written as:
8693 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
8698 @subsection Commands
8700 This filter supports the following commands:
8706 Modify the hue and/or the saturation and/or brightness of the input video.
8707 The command accepts the same syntax of the corresponding option.
8709 If the specified expression is not valid, it is kept at its current
8715 Detect video interlacing type.
8717 This filter tries to detect if the input frames as interlaced, progressive,
8718 top or bottom field first. It will also try and detect fields that are
8719 repeated between adjacent frames (a sign of telecine).
8721 Single frame detection considers only immediately adjacent frames when classifying each frame.
8722 Multiple frame detection incorporates the classification history of previous frames.
8724 The filter will log these metadata values:
8727 @item single.current_frame
8728 Detected type of current frame using single-frame detection. One of:
8729 ``tff'' (top field first), ``bff'' (bottom field first),
8730 ``progressive'', or ``undetermined''
8733 Cumulative number of frames detected as top field first using single-frame detection.
8736 Cumulative number of frames detected as top field first using multiple-frame detection.
8739 Cumulative number of frames detected as bottom field first using single-frame detection.
8741 @item multiple.current_frame
8742 Detected type of current frame using multiple-frame detection. One of:
8743 ``tff'' (top field first), ``bff'' (bottom field first),
8744 ``progressive'', or ``undetermined''
8747 Cumulative number of frames detected as bottom field first using multiple-frame detection.
8749 @item single.progressive
8750 Cumulative number of frames detected as progressive using single-frame detection.
8752 @item multiple.progressive
8753 Cumulative number of frames detected as progressive using multiple-frame detection.
8755 @item single.undetermined
8756 Cumulative number of frames that could not be classified using single-frame detection.
8758 @item multiple.undetermined
8759 Cumulative number of frames that could not be classified using multiple-frame detection.
8761 @item repeated.current_frame
8762 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
8764 @item repeated.neither
8765 Cumulative number of frames with no repeated field.
8768 Cumulative number of frames with the top field repeated from the previous frame's top field.
8770 @item repeated.bottom
8771 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
8774 The filter accepts the following options:
8778 Set interlacing threshold.
8780 Set progressive threshold.
8782 Threshold for repeated field detection.
8784 Number of frames after which a given frame's contribution to the
8785 statistics is halved (i.e., it contributes only 0.5 to it's
8786 classification). The default of 0 means that all frames seen are given
8787 full weight of 1.0 forever.
8788 @item analyze_interlaced_flag
8789 When this is not 0 then idet will use the specified number of frames to determine
8790 if the interlaced flag is accurate, it will not count undetermined frames.
8791 If the flag is found to be accurate it will be used without any further
8792 computations, if it is found to be inaccurate it will be cleared without any
8793 further computations. This allows inserting the idet filter as a low computational
8794 method to clean up the interlaced flag
8799 Deinterleave or interleave fields.
8801 This filter allows one to process interlaced images fields without
8802 deinterlacing them. Deinterleaving splits the input frame into 2
8803 fields (so called half pictures). Odd lines are moved to the top
8804 half of the output image, even lines to the bottom half.
8805 You can process (filter) them independently and then re-interleave them.
8807 The filter accepts the following options:
8811 @item chroma_mode, c
8813 Available values for @var{luma_mode}, @var{chroma_mode} and
8814 @var{alpha_mode} are:
8820 @item deinterleave, d
8821 Deinterleave fields, placing one above the other.
8824 Interleave fields. Reverse the effect of deinterleaving.
8826 Default value is @code{none}.
8829 @item chroma_swap, cs
8830 @item alpha_swap, as
8831 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
8836 Apply inflate effect to the video.
8838 This filter replaces the pixel by the local(3x3) average by taking into account
8839 only values higher than the pixel.
8841 It accepts the following options:
8848 Limit the maximum change for each plane, default is 65535.
8849 If 0, plane will remain unchanged.
8854 Simple interlacing filter from progressive contents. This interleaves upper (or
8855 lower) lines from odd frames with lower (or upper) lines from even frames,
8856 halving the frame rate and preserving image height.
8859 Original Original New Frame
8860 Frame 'j' Frame 'j+1' (tff)
8861 ========== =========== ==================
8862 Line 0 --------------------> Frame 'j' Line 0
8863 Line 1 Line 1 ----> Frame 'j+1' Line 1
8864 Line 2 ---------------------> Frame 'j' Line 2
8865 Line 3 Line 3 ----> Frame 'j+1' Line 3
8867 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
8870 It accepts the following optional parameters:
8874 This determines whether the interlaced frame is taken from the even
8875 (tff - default) or odd (bff) lines of the progressive frame.
8878 Enable (default) or disable the vertical lowpass filter to avoid twitter
8879 interlacing and reduce moire patterns.
8884 Deinterlace input video by applying Donald Graft's adaptive kernel
8885 deinterling. Work on interlaced parts of a video to produce
8888 The description of the accepted parameters follows.
8892 Set the threshold which affects the filter's tolerance when
8893 determining if a pixel line must be processed. It must be an integer
8894 in the range [0,255] and defaults to 10. A value of 0 will result in
8895 applying the process on every pixels.
8898 Paint pixels exceeding the threshold value to white if set to 1.
8902 Set the fields order. Swap fields if set to 1, leave fields alone if
8906 Enable additional sharpening if set to 1. Default is 0.
8909 Enable twoway sharpening if set to 1. Default is 0.
8912 @subsection Examples
8916 Apply default values:
8918 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
8922 Enable additional sharpening:
8928 Paint processed pixels in white:
8934 @section lenscorrection
8936 Correct radial lens distortion
8938 This filter can be used to correct for radial distortion as can result from the use
8939 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
8940 one can use tools available for example as part of opencv or simply trial-and-error.
8941 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
8942 and extract the k1 and k2 coefficients from the resulting matrix.
8944 Note that effectively the same filter is available in the open-source tools Krita and
8945 Digikam from the KDE project.
8947 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
8948 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
8949 brightness distribution, so you may want to use both filters together in certain
8950 cases, though you will have to take care of ordering, i.e. whether vignetting should
8951 be applied before or after lens correction.
8955 The filter accepts the following options:
8959 Relative x-coordinate of the focal point of the image, and thereby the center of the
8960 distortion. This value has a range [0,1] and is expressed as fractions of the image
8963 Relative y-coordinate of the focal point of the image, and thereby the center of the
8964 distortion. This value has a range [0,1] and is expressed as fractions of the image
8967 Coefficient of the quadratic correction term. 0.5 means no correction.
8969 Coefficient of the double quadratic correction term. 0.5 means no correction.
8972 The formula that generates the correction is:
8974 @var{r_src} = @var{r_tgt} * (1 + @var{k1} * (@var{r_tgt} / @var{r_0})^2 + @var{k2} * (@var{r_tgt} / @var{r_0})^4)
8976 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
8977 distances from the focal point in the source and target images, respectively.
8979 @section loop, aloop
8981 Loop video frames or audio samples.
8983 Those filters accepts the following options:
8987 Set the number of loops.
8990 Set maximal size in number of frames for @code{loop} filter or maximal number
8991 of samples in case of @code{aloop} filter.
8994 Set first frame of loop for @code{loop} filter or first sample of loop in case
8995 of @code{aloop} filter.
9001 Apply a 3D LUT to an input video.
9003 The filter accepts the following options:
9007 Set the 3D LUT file name.
9009 Currently supported formats:
9021 Select interpolation mode.
9023 Available values are:
9027 Use values from the nearest defined point.
9029 Interpolate values using the 8 points defining a cube.
9031 Interpolate values using a tetrahedron.
9035 @section lut, lutrgb, lutyuv
9037 Compute a look-up table for binding each pixel component input value
9038 to an output value, and apply it to the input video.
9040 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
9041 to an RGB input video.
9043 These filters accept the following parameters:
9046 set first pixel component expression
9048 set second pixel component expression
9050 set third pixel component expression
9052 set fourth pixel component expression, corresponds to the alpha component
9055 set red component expression
9057 set green component expression
9059 set blue component expression
9061 alpha component expression
9064 set Y/luminance component expression
9066 set U/Cb component expression
9068 set V/Cr component expression
9071 Each of them specifies the expression to use for computing the lookup table for
9072 the corresponding pixel component values.
9074 The exact component associated to each of the @var{c*} options depends on the
9077 The @var{lut} filter requires either YUV or RGB pixel formats in input,
9078 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
9080 The expressions can contain the following constants and functions:
9085 The input width and height.
9088 The input value for the pixel component.
9091 The input value, clipped to the @var{minval}-@var{maxval} range.
9094 The maximum value for the pixel component.
9097 The minimum value for the pixel component.
9100 The negated value for the pixel component value, clipped to the
9101 @var{minval}-@var{maxval} range; it corresponds to the expression
9102 "maxval-clipval+minval".
9105 The computed value in @var{val}, clipped to the
9106 @var{minval}-@var{maxval} range.
9108 @item gammaval(gamma)
9109 The computed gamma correction value of the pixel component value,
9110 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
9112 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
9116 All expressions default to "val".
9118 @subsection Examples
9124 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
9125 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
9128 The above is the same as:
9130 lutrgb="r=negval:g=negval:b=negval"
9131 lutyuv="y=negval:u=negval:v=negval"
9141 Remove chroma components, turning the video into a graytone image:
9143 lutyuv="u=128:v=128"
9147 Apply a luma burning effect:
9153 Remove green and blue components:
9159 Set a constant alpha channel value on input:
9161 format=rgba,lutrgb=a="maxval-minval/2"
9165 Correct luminance gamma by a factor of 0.5:
9167 lutyuv=y=gammaval(0.5)
9171 Discard least significant bits of luma:
9173 lutyuv=y='bitand(val, 128+64+32)'
9177 @section maskedmerge
9179 Merge the first input stream with the second input stream using per pixel
9180 weights in the third input stream.
9182 A value of 0 in the third stream pixel component means that pixel component
9183 from first stream is returned unchanged, while maximum value (eg. 255 for
9184 8-bit videos) means that pixel component from second stream is returned
9185 unchanged. Intermediate values define the amount of merging between both
9186 input stream's pixel components.
9188 This filter accepts the following options:
9191 Set which planes will be processed as bitmap, unprocessed planes will be
9192 copied from first stream.
9193 By default value 0xf, all planes will be processed.
9198 Apply motion-compensation deinterlacing.
9200 It needs one field per frame as input and must thus be used together
9201 with yadif=1/3 or equivalent.
9203 This filter accepts the following options:
9206 Set the deinterlacing mode.
9208 It accepts one of the following values:
9213 use iterative motion estimation
9215 like @samp{slow}, but use multiple reference frames.
9217 Default value is @samp{fast}.
9220 Set the picture field parity assumed for the input video. It must be
9221 one of the following values:
9225 assume top field first
9227 assume bottom field first
9230 Default value is @samp{bff}.
9233 Set per-block quantization parameter (QP) used by the internal
9236 Higher values should result in a smoother motion vector field but less
9237 optimal individual vectors. Default value is 1.
9240 @section mergeplanes
9242 Merge color channel components from several video streams.
9244 The filter accepts up to 4 input streams, and merge selected input
9245 planes to the output video.
9247 This filter accepts the following options:
9250 Set input to output plane mapping. Default is @code{0}.
9252 The mappings is specified as a bitmap. It should be specified as a
9253 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
9254 mapping for the first plane of the output stream. 'A' sets the number of
9255 the input stream to use (from 0 to 3), and 'a' the plane number of the
9256 corresponding input to use (from 0 to 3). The rest of the mappings is
9257 similar, 'Bb' describes the mapping for the output stream second
9258 plane, 'Cc' describes the mapping for the output stream third plane and
9259 'Dd' describes the mapping for the output stream fourth plane.
9262 Set output pixel format. Default is @code{yuva444p}.
9265 @subsection Examples
9269 Merge three gray video streams of same width and height into single video stream:
9271 [a0][a1][a2]mergeplanes=0x001020:yuv444p
9275 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
9277 [a0][a1]mergeplanes=0x00010210:yuva444p
9281 Swap Y and A plane in yuva444p stream:
9283 format=yuva444p,mergeplanes=0x03010200:yuva444p
9287 Swap U and V plane in yuv420p stream:
9289 format=yuv420p,mergeplanes=0x000201:yuv420p
9293 Cast a rgb24 clip to yuv444p:
9295 format=rgb24,mergeplanes=0x000102:yuv444p
9299 @section metadata, ametadata
9301 Manipulate frame metadata.
9303 This filter accepts the following options:
9307 Set mode of operation of the filter.
9309 Can be one of the following:
9313 If both @code{value} and @code{key} is set, select frames
9314 which have such metadata. If only @code{key} is set, select
9315 every frame that has such key in metadata.
9318 Add new metadata @code{key} and @code{value}. If key is already available
9322 Modify value of already present key.
9325 If @code{value} is set, delete only keys that have such value.
9326 Otherwise, delete key.
9329 Print key and its value if metadata was found. If @code{key} is not set print all
9330 metadata values available in frame.
9334 Set key used with all modes. Must be set for all modes except @code{print}.
9337 Set metadata value which will be used. This option is mandatory for
9338 @code{modify} and @code{add} mode.
9341 Which function to use when comparing metadata value and @code{value}.
9343 Can be one of following:
9347 Values are interpreted as strings, returns true if metadata value is same as @code{value}.
9350 Values are interpreted as strings, returns true if metadata value starts with
9351 the @code{value} option string.
9354 Values are interpreted as floats, returns true if metadata value is less than @code{value}.
9357 Values are interpreted as floats, returns true if @code{value} is equal with metadata value.
9360 Values are interpreted as floats, returns true if metadata value is greater than @code{value}.
9363 Values are interpreted as floats, returns true if expression from option @code{expr}
9368 Set expression which is used when @code{function} is set to @code{expr}.
9369 The expression is evaluated through the eval API and can contain the following
9374 Float representation of @code{value} from metadata key.
9377 Float representation of @code{value} as supplied by user in @code{value} option.
9381 If specified in @code{print} mode, output is written to the named file. When
9382 filename equals "-" data is written to standard output.
9383 If @code{file} option is not set, output is written to the log with AV_LOG_INFO
9387 @subsection Examples
9391 Print all metadata values for frames with key @code{lavfi.singnalstats.YDIF} with values
9395 signalstats,metadata=print:key=lavfi.signalstats.YDIF:value=0:function=expr:expr='between(VALUE1,0,1)'
9400 Drop frames that do not differ greatly from the previous frame in
9401 order to reduce frame rate.
9403 The main use of this filter is for very-low-bitrate encoding
9404 (e.g. streaming over dialup modem), but it could in theory be used for
9405 fixing movies that were inverse-telecined incorrectly.
9407 A description of the accepted options follows.
9411 Set the maximum number of consecutive frames which can be dropped (if
9412 positive), or the minimum interval between dropped frames (if
9413 negative). If the value is 0, the frame is dropped unregarding the
9414 number of previous sequentially dropped frames.
9421 Set the dropping threshold values.
9423 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
9424 represent actual pixel value differences, so a threshold of 64
9425 corresponds to 1 unit of difference for each pixel, or the same spread
9426 out differently over the block.
9428 A frame is a candidate for dropping if no 8x8 blocks differ by more
9429 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
9430 meaning the whole image) differ by more than a threshold of @option{lo}.
9432 Default value for @option{hi} is 64*12, default value for @option{lo} is
9433 64*5, and default value for @option{frac} is 0.33.
9441 It accepts an integer in input; if non-zero it negates the
9442 alpha component (if available). The default value in input is 0.
9446 Deinterlace video using neural network edge directed interpolation.
9448 This filter accepts the following options:
9452 Mandatory option, without binary file filter can not work.
9453 Currently file can be found here:
9454 https://github.com/dubhater/vapoursynth-nnedi3/blob/master/src/nnedi3_weights.bin
9457 Set which frames to deinterlace, by default it is @code{all}.
9458 Can be @code{all} or @code{interlaced}.
9461 Set mode of operation.
9463 Can be one of the following:
9467 Use frame flags, both fields.
9469 Use frame flags, single field.
9473 Use bottom field only.
9475 Use both fields, top first.
9477 Use both fields, bottom first.
9481 Set which planes to process, by default filter process all frames.
9484 Set size of local neighborhood around each pixel, used by the predictor neural
9487 Can be one of the following:
9500 Set the number of neurons in predicctor neural network.
9501 Can be one of the following:
9512 Controls the number of different neural network predictions that are blended
9513 together to compute the final output value. Can be @code{fast}, default or
9517 Set which set of weights to use in the predictor.
9518 Can be one of the following:
9522 weights trained to minimize absolute error
9524 weights trained to minimize squared error
9528 Controls whether or not the prescreener neural network is used to decide
9529 which pixels should be processed by the predictor neural network and which
9530 can be handled by simple cubic interpolation.
9531 The prescreener is trained to know whether cubic interpolation will be
9532 sufficient for a pixel or whether it should be predicted by the predictor nn.
9533 The computational complexity of the prescreener nn is much less than that of
9534 the predictor nn. Since most pixels can be handled by cubic interpolation,
9535 using the prescreener generally results in much faster processing.
9536 The prescreener is pretty accurate, so the difference between using it and not
9537 using it is almost always unnoticeable.
9539 Can be one of the following:
9547 Default is @code{new}.
9550 Set various debugging flags.
9555 Force libavfilter not to use any of the specified pixel formats for the
9556 input to the next filter.
9558 It accepts the following parameters:
9562 A '|'-separated list of pixel format names, such as
9563 apix_fmts=yuv420p|monow|rgb24".
9567 @subsection Examples
9571 Force libavfilter to use a format different from @var{yuv420p} for the
9572 input to the vflip filter:
9574 noformat=pix_fmts=yuv420p,vflip
9578 Convert the input video to any of the formats not contained in the list:
9580 noformat=yuv420p|yuv444p|yuv410p
9586 Add noise on video input frame.
9588 The filter accepts the following options:
9596 Set noise seed for specific pixel component or all pixel components in case
9597 of @var{all_seed}. Default value is @code{123457}.
9599 @item all_strength, alls
9600 @item c0_strength, c0s
9601 @item c1_strength, c1s
9602 @item c2_strength, c2s
9603 @item c3_strength, c3s
9604 Set noise strength for specific pixel component or all pixel components in case
9605 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
9607 @item all_flags, allf
9612 Set pixel component flags or set flags for all components if @var{all_flags}.
9613 Available values for component flags are:
9616 averaged temporal noise (smoother)
9618 mix random noise with a (semi)regular pattern
9620 temporal noise (noise pattern changes between frames)
9622 uniform noise (gaussian otherwise)
9626 @subsection Examples
9628 Add temporal and uniform noise to input video:
9630 noise=alls=20:allf=t+u
9635 Pass the video source unchanged to the output.
9638 Optical Character Recognition
9640 This filter uses Tesseract for optical character recognition.
9642 It accepts the following options:
9646 Set datapath to tesseract data. Default is to use whatever was
9647 set at installation.
9650 Set language, default is "eng".
9653 Set character whitelist.
9656 Set character blacklist.
9659 The filter exports recognized text as the frame metadata @code{lavfi.ocr.text}.
9663 Apply a video transform using libopencv.
9665 To enable this filter, install the libopencv library and headers and
9666 configure FFmpeg with @code{--enable-libopencv}.
9668 It accepts the following parameters:
9673 The name of the libopencv filter to apply.
9676 The parameters to pass to the libopencv filter. If not specified, the default
9681 Refer to the official libopencv documentation for more precise
9683 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
9685 Several libopencv filters are supported; see the following subsections.
9690 Dilate an image by using a specific structuring element.
9691 It corresponds to the libopencv function @code{cvDilate}.
9693 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
9695 @var{struct_el} represents a structuring element, and has the syntax:
9696 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
9698 @var{cols} and @var{rows} represent the number of columns and rows of
9699 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
9700 point, and @var{shape} the shape for the structuring element. @var{shape}
9701 must be "rect", "cross", "ellipse", or "custom".
9703 If the value for @var{shape} is "custom", it must be followed by a
9704 string of the form "=@var{filename}". The file with name
9705 @var{filename} is assumed to represent a binary image, with each
9706 printable character corresponding to a bright pixel. When a custom
9707 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
9708 or columns and rows of the read file are assumed instead.
9710 The default value for @var{struct_el} is "3x3+0x0/rect".
9712 @var{nb_iterations} specifies the number of times the transform is
9713 applied to the image, and defaults to 1.
9717 # Use the default values
9720 # Dilate using a structuring element with a 5x5 cross, iterating two times
9721 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
9723 # Read the shape from the file diamond.shape, iterating two times.
9724 # The file diamond.shape may contain a pattern of characters like this
9730 # The specified columns and rows are ignored
9731 # but the anchor point coordinates are not
9732 ocv=dilate:0x0+2x2/custom=diamond.shape|2
9737 Erode an image by using a specific structuring element.
9738 It corresponds to the libopencv function @code{cvErode}.
9740 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
9741 with the same syntax and semantics as the @ref{dilate} filter.
9745 Smooth the input video.
9747 The filter takes the following parameters:
9748 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
9750 @var{type} is the type of smooth filter to apply, and must be one of
9751 the following values: "blur", "blur_no_scale", "median", "gaussian",
9752 or "bilateral". The default value is "gaussian".
9754 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
9755 depend on the smooth type. @var{param1} and
9756 @var{param2} accept integer positive values or 0. @var{param3} and
9757 @var{param4} accept floating point values.
9759 The default value for @var{param1} is 3. The default value for the
9760 other parameters is 0.
9762 These parameters correspond to the parameters assigned to the
9763 libopencv function @code{cvSmooth}.
9768 Overlay one video on top of another.
9770 It takes two inputs and has one output. The first input is the "main"
9771 video on which the second input is overlaid.
9773 It accepts the following parameters:
9775 A description of the accepted options follows.
9780 Set the expression for the x and y coordinates of the overlaid video
9781 on the main video. Default value is "0" for both expressions. In case
9782 the expression is invalid, it is set to a huge value (meaning that the
9783 overlay will not be displayed within the output visible area).
9786 The action to take when EOF is encountered on the secondary input; it accepts
9787 one of the following values:
9791 Repeat the last frame (the default).
9795 Pass the main input through.
9799 Set when the expressions for @option{x}, and @option{y} are evaluated.
9801 It accepts the following values:
9804 only evaluate expressions once during the filter initialization or
9805 when a command is processed
9808 evaluate expressions for each incoming frame
9811 Default value is @samp{frame}.
9814 If set to 1, force the output to terminate when the shortest input
9815 terminates. Default value is 0.
9818 Set the format for the output video.
9820 It accepts the following values:
9835 Default value is @samp{yuv420}.
9837 @item rgb @emph{(deprecated)}
9838 If set to 1, force the filter to accept inputs in the RGB
9839 color space. Default value is 0. This option is deprecated, use
9840 @option{format} instead.
9843 If set to 1, force the filter to draw the last overlay frame over the
9844 main input until the end of the stream. A value of 0 disables this
9845 behavior. Default value is 1.
9848 The @option{x}, and @option{y} expressions can contain the following
9854 The main input width and height.
9858 The overlay input width and height.
9862 The computed values for @var{x} and @var{y}. They are evaluated for
9867 horizontal and vertical chroma subsample values of the output
9868 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
9872 the number of input frame, starting from 0
9875 the position in the file of the input frame, NAN if unknown
9878 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
9882 Note that the @var{n}, @var{pos}, @var{t} variables are available only
9883 when evaluation is done @emph{per frame}, and will evaluate to NAN
9884 when @option{eval} is set to @samp{init}.
9886 Be aware that frames are taken from each input video in timestamp
9887 order, hence, if their initial timestamps differ, it is a good idea
9888 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
9889 have them begin in the same zero timestamp, as the example for
9890 the @var{movie} filter does.
9892 You can chain together more overlays but you should test the
9893 efficiency of such approach.
9895 @subsection Commands
9897 This filter supports the following commands:
9901 Modify the x and y of the overlay input.
9902 The command accepts the same syntax of the corresponding option.
9904 If the specified expression is not valid, it is kept at its current
9908 @subsection Examples
9912 Draw the overlay at 10 pixels from the bottom right corner of the main
9915 overlay=main_w-overlay_w-10:main_h-overlay_h-10
9918 Using named options the example above becomes:
9920 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
9924 Insert a transparent PNG logo in the bottom left corner of the input,
9925 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
9927 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
9931 Insert 2 different transparent PNG logos (second logo on bottom
9932 right corner) using the @command{ffmpeg} tool:
9934 ffmpeg -i input -i logo1 -i logo2 -filter_complex 'overlay=x=10:y=H-h-10,overlay=x=W-w-10:y=H-h-10' output
9938 Add a transparent color layer on top of the main video; @code{WxH}
9939 must specify the size of the main input to the overlay filter:
9941 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
9945 Play an original video and a filtered version (here with the deshake
9946 filter) side by side using the @command{ffplay} tool:
9948 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
9951 The above command is the same as:
9953 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
9957 Make a sliding overlay appearing from the left to the right top part of the
9958 screen starting since time 2:
9960 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
9964 Compose output by putting two input videos side to side:
9966 ffmpeg -i left.avi -i right.avi -filter_complex "
9967 nullsrc=size=200x100 [background];
9968 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
9969 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
9970 [background][left] overlay=shortest=1 [background+left];
9971 [background+left][right] overlay=shortest=1:x=100 [left+right]
9976 Mask 10-20 seconds of a video by applying the delogo filter to a section
9978 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
9979 -vf '[in]split[split_main][split_delogo];[split_delogo]trim=start=360:end=371,delogo=0:0:640:480[delogoed];[split_main][delogoed]overlay=eof_action=pass[out]'
9984 Chain several overlays in cascade:
9986 nullsrc=s=200x200 [bg];
9987 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
9988 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
9989 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
9990 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
9991 [in3] null, [mid2] overlay=100:100 [out0]
9998 Apply Overcomplete Wavelet denoiser.
10000 The filter accepts the following options:
10006 Larger depth values will denoise lower frequency components more, but
10007 slow down filtering.
10009 Must be an int in the range 8-16, default is @code{8}.
10011 @item luma_strength, ls
10014 Must be a double value in the range 0-1000, default is @code{1.0}.
10016 @item chroma_strength, cs
10017 Set chroma strength.
10019 Must be a double value in the range 0-1000, default is @code{1.0}.
10025 Add paddings to the input image, and place the original input at the
10026 provided @var{x}, @var{y} coordinates.
10028 It accepts the following parameters:
10033 Specify an expression for the size of the output image with the
10034 paddings added. If the value for @var{width} or @var{height} is 0, the
10035 corresponding input size is used for the output.
10037 The @var{width} expression can reference the value set by the
10038 @var{height} expression, and vice versa.
10040 The default value of @var{width} and @var{height} is 0.
10044 Specify the offsets to place the input image at within the padded area,
10045 with respect to the top/left border of the output image.
10047 The @var{x} expression can reference the value set by the @var{y}
10048 expression, and vice versa.
10050 The default value of @var{x} and @var{y} is 0.
10053 Specify the color of the padded area. For the syntax of this option,
10054 check the "Color" section in the ffmpeg-utils manual.
10056 The default value of @var{color} is "black".
10059 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
10060 options are expressions containing the following constants:
10065 The input video width and height.
10069 These are the same as @var{in_w} and @var{in_h}.
10073 The output width and height (the size of the padded area), as
10074 specified by the @var{width} and @var{height} expressions.
10078 These are the same as @var{out_w} and @var{out_h}.
10082 The x and y offsets as specified by the @var{x} and @var{y}
10083 expressions, or NAN if not yet specified.
10086 same as @var{iw} / @var{ih}
10089 input sample aspect ratio
10092 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
10096 The horizontal and vertical chroma subsample values. For example for the
10097 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
10100 @subsection Examples
10104 Add paddings with the color "violet" to the input video. The output video
10105 size is 640x480, and the top-left corner of the input video is placed at
10108 pad=640:480:0:40:violet
10111 The example above is equivalent to the following command:
10113 pad=width=640:height=480:x=0:y=40:color=violet
10117 Pad the input to get an output with dimensions increased by 3/2,
10118 and put the input video at the center of the padded area:
10120 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
10124 Pad the input to get a squared output with size equal to the maximum
10125 value between the input width and height, and put the input video at
10126 the center of the padded area:
10128 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
10132 Pad the input to get a final w/h ratio of 16:9:
10134 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
10138 In case of anamorphic video, in order to set the output display aspect
10139 correctly, it is necessary to use @var{sar} in the expression,
10140 according to the relation:
10142 (ih * X / ih) * sar = output_dar
10143 X = output_dar / sar
10146 Thus the previous example needs to be modified to:
10148 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
10152 Double the output size and put the input video in the bottom-right
10153 corner of the output padded area:
10155 pad="2*iw:2*ih:ow-iw:oh-ih"
10159 @anchor{palettegen}
10160 @section palettegen
10162 Generate one palette for a whole video stream.
10164 It accepts the following options:
10168 Set the maximum number of colors to quantize in the palette.
10169 Note: the palette will still contain 256 colors; the unused palette entries
10172 @item reserve_transparent
10173 Create a palette of 255 colors maximum and reserve the last one for
10174 transparency. Reserving the transparency color is useful for GIF optimization.
10175 If not set, the maximum of colors in the palette will be 256. You probably want
10176 to disable this option for a standalone image.
10180 Set statistics mode.
10182 It accepts the following values:
10185 Compute full frame histograms.
10187 Compute histograms only for the part that differs from previous frame. This
10188 might be relevant to give more importance to the moving part of your input if
10189 the background is static.
10192 Default value is @var{full}.
10195 The filter also exports the frame metadata @code{lavfi.color_quant_ratio}
10196 (@code{nb_color_in / nb_color_out}) which you can use to evaluate the degree of
10197 color quantization of the palette. This information is also visible at
10198 @var{info} logging level.
10200 @subsection Examples
10204 Generate a representative palette of a given video using @command{ffmpeg}:
10206 ffmpeg -i input.mkv -vf palettegen palette.png
10210 @section paletteuse
10212 Use a palette to downsample an input video stream.
10214 The filter takes two inputs: one video stream and a palette. The palette must
10215 be a 256 pixels image.
10217 It accepts the following options:
10221 Select dithering mode. Available algorithms are:
10224 Ordered 8x8 bayer dithering (deterministic)
10226 Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
10227 Note: this dithering is sometimes considered "wrong" and is included as a
10229 @item floyd_steinberg
10230 Floyd and Steingberg dithering (error diffusion)
10232 Frankie Sierra dithering v2 (error diffusion)
10234 Frankie Sierra dithering v2 "Lite" (error diffusion)
10237 Default is @var{sierra2_4a}.
10240 When @var{bayer} dithering is selected, this option defines the scale of the
10241 pattern (how much the crosshatch pattern is visible). A low value means more
10242 visible pattern for less banding, and higher value means less visible pattern
10243 at the cost of more banding.
10245 The option must be an integer value in the range [0,5]. Default is @var{2}.
10248 If set, define the zone to process
10252 Only the changing rectangle will be reprocessed. This is similar to GIF
10253 cropping/offsetting compression mechanism. This option can be useful for speed
10254 if only a part of the image is changing, and has use cases such as limiting the
10255 scope of the error diffusal @option{dither} to the rectangle that bounds the
10256 moving scene (it leads to more deterministic output if the scene doesn't change
10257 much, and as a result less moving noise and better GIF compression).
10260 Default is @var{none}.
10263 @subsection Examples
10267 Use a palette (generated for example with @ref{palettegen}) to encode a GIF
10268 using @command{ffmpeg}:
10270 ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
10274 @section perspective
10276 Correct perspective of video not recorded perpendicular to the screen.
10278 A description of the accepted parameters follows.
10289 Set coordinates expression for top left, top right, bottom left and bottom right corners.
10290 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
10291 If the @code{sense} option is set to @code{source}, then the specified points will be sent
10292 to the corners of the destination. If the @code{sense} option is set to @code{destination},
10293 then the corners of the source will be sent to the specified coordinates.
10295 The expressions can use the following variables:
10300 the width and height of video frame.
10304 Output frame count.
10307 @item interpolation
10308 Set interpolation for perspective correction.
10310 It accepts the following values:
10316 Default value is @samp{linear}.
10319 Set interpretation of coordinate options.
10321 It accepts the following values:
10325 Send point in the source specified by the given coordinates to
10326 the corners of the destination.
10328 @item 1, destination
10330 Send the corners of the source to the point in the destination specified
10331 by the given coordinates.
10333 Default value is @samp{source}.
10337 Set when the expressions for coordinates @option{x0,y0,...x3,y3} are evaluated.
10339 It accepts the following values:
10342 only evaluate expressions once during the filter initialization or
10343 when a command is processed
10346 evaluate expressions for each incoming frame
10349 Default value is @samp{init}.
10354 Delay interlaced video by one field time so that the field order changes.
10356 The intended use is to fix PAL movies that have been captured with the
10357 opposite field order to the film-to-video transfer.
10359 A description of the accepted parameters follows.
10365 It accepts the following values:
10368 Capture field order top-first, transfer bottom-first.
10369 Filter will delay the bottom field.
10372 Capture field order bottom-first, transfer top-first.
10373 Filter will delay the top field.
10376 Capture and transfer with the same field order. This mode only exists
10377 for the documentation of the other options to refer to, but if you
10378 actually select it, the filter will faithfully do nothing.
10381 Capture field order determined automatically by field flags, transfer
10383 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
10384 basis using field flags. If no field information is available,
10385 then this works just like @samp{u}.
10388 Capture unknown or varying, transfer opposite.
10389 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
10390 analyzing the images and selecting the alternative that produces best
10391 match between the fields.
10394 Capture top-first, transfer unknown or varying.
10395 Filter selects among @samp{t} and @samp{p} using image analysis.
10398 Capture bottom-first, transfer unknown or varying.
10399 Filter selects among @samp{b} and @samp{p} using image analysis.
10402 Capture determined by field flags, transfer unknown or varying.
10403 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
10404 image analysis. If no field information is available, then this works just
10405 like @samp{U}. This is the default mode.
10408 Both capture and transfer unknown or varying.
10409 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
10413 @section pixdesctest
10415 Pixel format descriptor test filter, mainly useful for internal
10416 testing. The output video should be equal to the input video.
10420 format=monow, pixdesctest
10423 can be used to test the monowhite pixel format descriptor definition.
10427 Enable the specified chain of postprocessing subfilters using libpostproc. This
10428 library should be automatically selected with a GPL build (@code{--enable-gpl}).
10429 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
10430 Each subfilter and some options have a short and a long name that can be used
10431 interchangeably, i.e. dr/dering are the same.
10433 The filters accept the following options:
10437 Set postprocessing subfilters string.
10440 All subfilters share common options to determine their scope:
10444 Honor the quality commands for this subfilter.
10447 Do chrominance filtering, too (default).
10450 Do luminance filtering only (no chrominance).
10453 Do chrominance filtering only (no luminance).
10456 These options can be appended after the subfilter name, separated by a '|'.
10458 Available subfilters are:
10461 @item hb/hdeblock[|difference[|flatness]]
10462 Horizontal deblocking filter
10465 Difference factor where higher values mean more deblocking (default: @code{32}).
10467 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10470 @item vb/vdeblock[|difference[|flatness]]
10471 Vertical deblocking filter
10474 Difference factor where higher values mean more deblocking (default: @code{32}).
10476 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10479 @item ha/hadeblock[|difference[|flatness]]
10480 Accurate horizontal deblocking filter
10483 Difference factor where higher values mean more deblocking (default: @code{32}).
10485 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10488 @item va/vadeblock[|difference[|flatness]]
10489 Accurate vertical deblocking filter
10492 Difference factor where higher values mean more deblocking (default: @code{32}).
10494 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10498 The horizontal and vertical deblocking filters share the difference and
10499 flatness values so you cannot set different horizontal and vertical
10503 @item h1/x1hdeblock
10504 Experimental horizontal deblocking filter
10506 @item v1/x1vdeblock
10507 Experimental vertical deblocking filter
10512 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
10515 larger -> stronger filtering
10517 larger -> stronger filtering
10519 larger -> stronger filtering
10522 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
10525 Stretch luminance to @code{0-255}.
10528 @item lb/linblenddeint
10529 Linear blend deinterlacing filter that deinterlaces the given block by
10530 filtering all lines with a @code{(1 2 1)} filter.
10532 @item li/linipoldeint
10533 Linear interpolating deinterlacing filter that deinterlaces the given block by
10534 linearly interpolating every second line.
10536 @item ci/cubicipoldeint
10537 Cubic interpolating deinterlacing filter deinterlaces the given block by
10538 cubically interpolating every second line.
10540 @item md/mediandeint
10541 Median deinterlacing filter that deinterlaces the given block by applying a
10542 median filter to every second line.
10544 @item fd/ffmpegdeint
10545 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
10546 second line with a @code{(-1 4 2 4 -1)} filter.
10549 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
10550 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
10552 @item fq/forceQuant[|quantizer]
10553 Overrides the quantizer table from the input with the constant quantizer you
10561 Default pp filter combination (@code{hb|a,vb|a,dr|a})
10564 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
10567 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
10570 @subsection Examples
10574 Apply horizontal and vertical deblocking, deringing and automatic
10575 brightness/contrast:
10581 Apply default filters without brightness/contrast correction:
10587 Apply default filters and temporal denoiser:
10589 pp=default/tmpnoise|1|2|3
10593 Apply deblocking on luminance only, and switch vertical deblocking on or off
10594 automatically depending on available CPU time:
10601 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
10602 similar to spp = 6 with 7 point DCT, where only the center sample is
10605 The filter accepts the following options:
10609 Force a constant quantization parameter. It accepts an integer in range
10610 0 to 63. If not set, the filter will use the QP from the video stream
10614 Set thresholding mode. Available modes are:
10618 Set hard thresholding.
10620 Set soft thresholding (better de-ringing effect, but likely blurrier).
10622 Set medium thresholding (good results, default).
10628 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
10629 Ratio) between two input videos.
10631 This filter takes in input two input videos, the first input is
10632 considered the "main" source and is passed unchanged to the
10633 output. The second input is used as a "reference" video for computing
10636 Both video inputs must have the same resolution and pixel format for
10637 this filter to work correctly. Also it assumes that both inputs
10638 have the same number of frames, which are compared one by one.
10640 The obtained average PSNR is printed through the logging system.
10642 The filter stores the accumulated MSE (mean squared error) of each
10643 frame, and at the end of the processing it is averaged across all frames
10644 equally, and the following formula is applied to obtain the PSNR:
10647 PSNR = 10*log10(MAX^2/MSE)
10650 Where MAX is the average of the maximum values of each component of the
10653 The description of the accepted parameters follows.
10656 @item stats_file, f
10657 If specified the filter will use the named file to save the PSNR of
10658 each individual frame. When filename equals "-" the data is sent to
10662 The file printed if @var{stats_file} is selected, contains a sequence of
10663 key/value pairs of the form @var{key}:@var{value} for each compared
10666 A description of each shown parameter follows:
10670 sequential number of the input frame, starting from 1
10673 Mean Square Error pixel-by-pixel average difference of the compared
10674 frames, averaged over all the image components.
10676 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
10677 Mean Square Error pixel-by-pixel average difference of the compared
10678 frames for the component specified by the suffix.
10680 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
10681 Peak Signal to Noise ratio of the compared frames for the component
10682 specified by the suffix.
10687 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
10688 [main][ref] psnr="stats_file=stats.log" [out]
10691 On this example the input file being processed is compared with the
10692 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
10693 is stored in @file{stats.log}.
10698 Pulldown reversal (inverse telecine) filter, capable of handling mixed
10699 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
10702 The pullup filter is designed to take advantage of future context in making
10703 its decisions. This filter is stateless in the sense that it does not lock
10704 onto a pattern to follow, but it instead looks forward to the following
10705 fields in order to identify matches and rebuild progressive frames.
10707 To produce content with an even framerate, insert the fps filter after
10708 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
10709 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
10711 The filter accepts the following options:
10718 These options set the amount of "junk" to ignore at the left, right, top, and
10719 bottom of the image, respectively. Left and right are in units of 8 pixels,
10720 while top and bottom are in units of 2 lines.
10721 The default is 8 pixels on each side.
10724 Set the strict breaks. Setting this option to 1 will reduce the chances of
10725 filter generating an occasional mismatched frame, but it may also cause an
10726 excessive number of frames to be dropped during high motion sequences.
10727 Conversely, setting it to -1 will make filter match fields more easily.
10728 This may help processing of video where there is slight blurring between
10729 the fields, but may also cause there to be interlaced frames in the output.
10730 Default value is @code{0}.
10733 Set the metric plane to use. It accepts the following values:
10739 Use chroma blue plane.
10742 Use chroma red plane.
10745 This option may be set to use chroma plane instead of the default luma plane
10746 for doing filter's computations. This may improve accuracy on very clean
10747 source material, but more likely will decrease accuracy, especially if there
10748 is chroma noise (rainbow effect) or any grayscale video.
10749 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
10750 load and make pullup usable in realtime on slow machines.
10753 For best results (without duplicated frames in the output file) it is
10754 necessary to change the output frame rate. For example, to inverse
10755 telecine NTSC input:
10757 ffmpeg -i input -vf pullup -r 24000/1001 ...
10762 Change video quantization parameters (QP).
10764 The filter accepts the following option:
10768 Set expression for quantization parameter.
10771 The expression is evaluated through the eval API and can contain, among others,
10772 the following constants:
10776 1 if index is not 129, 0 otherwise.
10779 Sequentional index starting from -129 to 128.
10782 @subsection Examples
10786 Some equation like:
10794 Flush video frames from internal cache of frames into a random order.
10795 No frame is discarded.
10796 Inspired by @ref{frei0r} nervous filter.
10800 Set size in number of frames of internal cache, in range from @code{2} to
10801 @code{512}. Default is @code{30}.
10804 Set seed for random number generator, must be an integer included between
10805 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
10806 less than @code{0}, the filter will try to use a good random seed on a
10812 Read vertical interval timecode (VITC) information from the top lines of a
10815 The filter adds frame metadata key @code{lavfi.readvitc.tc_str} with the
10816 timecode value, if a valid timecode has been detected. Further metadata key
10817 @code{lavfi.readvitc.found} is set to 0/1 depending on whether
10818 timecode data has been found or not.
10820 This filter accepts the following options:
10824 Set the maximum number of lines to scan for VITC data. If the value is set to
10825 @code{-1} the full video frame is scanned. Default is @code{45}.
10828 Set the luma threshold for black. Accepts float numbers in the range [0.0,1.0],
10829 default value is @code{0.2}. The value must be equal or less than @code{thr_w}.
10832 Set the luma threshold for white. Accepts float numbers in the range [0.0,1.0],
10833 default value is @code{0.6}. The value must be equal or greater than @code{thr_b}.
10836 @subsection Examples
10840 Detect and draw VITC data onto the video frame; if no valid VITC is detected,
10841 draw @code{--:--:--:--} as a placeholder:
10843 ffmpeg -i input.avi -filter:v 'readvitc,drawtext=fontfile=FreeMono.ttf:text=%@{metadata\\:lavfi.readvitc.tc_str\\:--\\\\\\:--\\\\\\:--\\\\\\:--@}:x=(w-tw)/2:y=400-ascent'
10849 Remap pixels using 2nd: Xmap and 3rd: Ymap input video stream.
10851 Destination pixel at position (X, Y) will be picked from source (x, y) position
10852 where x = Xmap(X, Y) and y = Ymap(X, Y). If mapping values are out of range, zero
10853 value for pixel will be used for destination pixel.
10855 Xmap and Ymap input video streams must be of same dimensions. Output video stream
10856 will have Xmap/Ymap video stream dimensions.
10857 Xmap and Ymap input video streams are 16bit depth, single channel.
10859 @section removegrain
10861 The removegrain filter is a spatial denoiser for progressive video.
10865 Set mode for the first plane.
10868 Set mode for the second plane.
10871 Set mode for the third plane.
10874 Set mode for the fourth plane.
10877 Range of mode is from 0 to 24. Description of each mode follows:
10881 Leave input plane unchanged. Default.
10884 Clips the pixel with the minimum and maximum of the 8 neighbour pixels.
10887 Clips the pixel with the second minimum and maximum of the 8 neighbour pixels.
10890 Clips the pixel with the third minimum and maximum of the 8 neighbour pixels.
10893 Clips the pixel with the fourth minimum and maximum of the 8 neighbour pixels.
10894 This is equivalent to a median filter.
10897 Line-sensitive clipping giving the minimal change.
10900 Line-sensitive clipping, intermediate.
10903 Line-sensitive clipping, intermediate.
10906 Line-sensitive clipping, intermediate.
10909 Line-sensitive clipping on a line where the neighbours pixels are the closest.
10912 Replaces the target pixel with the closest neighbour.
10915 [1 2 1] horizontal and vertical kernel blur.
10921 Bob mode, interpolates top field from the line where the neighbours
10922 pixels are the closest.
10925 Bob mode, interpolates bottom field from the line where the neighbours
10926 pixels are the closest.
10929 Bob mode, interpolates top field. Same as 13 but with a more complicated
10930 interpolation formula.
10933 Bob mode, interpolates bottom field. Same as 14 but with a more complicated
10934 interpolation formula.
10937 Clips the pixel with the minimum and maximum of respectively the maximum and
10938 minimum of each pair of opposite neighbour pixels.
10941 Line-sensitive clipping using opposite neighbours whose greatest distance from
10942 the current pixel is minimal.
10945 Replaces the pixel with the average of its 8 neighbours.
10948 Averages the 9 pixels ([1 1 1] horizontal and vertical blur).
10951 Clips pixels using the averages of opposite neighbour.
10954 Same as mode 21 but simpler and faster.
10957 Small edge and halo removal, but reputed useless.
10963 @section removelogo
10965 Suppress a TV station logo, using an image file to determine which
10966 pixels comprise the logo. It works by filling in the pixels that
10967 comprise the logo with neighboring pixels.
10969 The filter accepts the following options:
10973 Set the filter bitmap file, which can be any image format supported by
10974 libavformat. The width and height of the image file must match those of the
10975 video stream being processed.
10978 Pixels in the provided bitmap image with a value of zero are not
10979 considered part of the logo, non-zero pixels are considered part of
10980 the logo. If you use white (255) for the logo and black (0) for the
10981 rest, you will be safe. For making the filter bitmap, it is
10982 recommended to take a screen capture of a black frame with the logo
10983 visible, and then using a threshold filter followed by the erode
10984 filter once or twice.
10986 If needed, little splotches can be fixed manually. Remember that if
10987 logo pixels are not covered, the filter quality will be much
10988 reduced. Marking too many pixels as part of the logo does not hurt as
10989 much, but it will increase the amount of blurring needed to cover over
10990 the image and will destroy more information than necessary, and extra
10991 pixels will slow things down on a large logo.
10993 @section repeatfields
10995 This filter uses the repeat_field flag from the Video ES headers and hard repeats
10996 fields based on its value.
10998 @section reverse, areverse
11002 Warning: This filter requires memory to buffer the entire clip, so trimming
11005 @subsection Examples
11009 Take the first 5 seconds of a clip, and reverse it.
11017 Rotate video by an arbitrary angle expressed in radians.
11019 The filter accepts the following options:
11021 A description of the optional parameters follows.
11024 Set an expression for the angle by which to rotate the input video
11025 clockwise, expressed as a number of radians. A negative value will
11026 result in a counter-clockwise rotation. By default it is set to "0".
11028 This expression is evaluated for each frame.
11031 Set the output width expression, default value is "iw".
11032 This expression is evaluated just once during configuration.
11035 Set the output height expression, default value is "ih".
11036 This expression is evaluated just once during configuration.
11039 Enable bilinear interpolation if set to 1, a value of 0 disables
11040 it. Default value is 1.
11043 Set the color used to fill the output area not covered by the rotated
11044 image. For the general syntax of this option, check the "Color" section in the
11045 ffmpeg-utils manual. If the special value "none" is selected then no
11046 background is printed (useful for example if the background is never shown).
11048 Default value is "black".
11051 The expressions for the angle and the output size can contain the
11052 following constants and functions:
11056 sequential number of the input frame, starting from 0. It is always NAN
11057 before the first frame is filtered.
11060 time in seconds of the input frame, it is set to 0 when the filter is
11061 configured. It is always NAN before the first frame is filtered.
11065 horizontal and vertical chroma subsample values. For example for the
11066 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11070 the input video width and height
11074 the output width and height, that is the size of the padded area as
11075 specified by the @var{width} and @var{height} expressions
11079 the minimal width/height required for completely containing the input
11080 video rotated by @var{a} radians.
11082 These are only available when computing the @option{out_w} and
11083 @option{out_h} expressions.
11086 @subsection Examples
11090 Rotate the input by PI/6 radians clockwise:
11096 Rotate the input by PI/6 radians counter-clockwise:
11102 Rotate the input by 45 degrees clockwise:
11108 Apply a constant rotation with period T, starting from an angle of PI/3:
11110 rotate=PI/3+2*PI*t/T
11114 Make the input video rotation oscillating with a period of T
11115 seconds and an amplitude of A radians:
11117 rotate=A*sin(2*PI/T*t)
11121 Rotate the video, output size is chosen so that the whole rotating
11122 input video is always completely contained in the output:
11124 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
11128 Rotate the video, reduce the output size so that no background is ever
11131 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
11135 @subsection Commands
11137 The filter supports the following commands:
11141 Set the angle expression.
11142 The command accepts the same syntax of the corresponding option.
11144 If the specified expression is not valid, it is kept at its current
11150 Apply Shape Adaptive Blur.
11152 The filter accepts the following options:
11155 @item luma_radius, lr
11156 Set luma blur filter strength, must be a value in range 0.1-4.0, default
11157 value is 1.0. A greater value will result in a more blurred image, and
11158 in slower processing.
11160 @item luma_pre_filter_radius, lpfr
11161 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
11164 @item luma_strength, ls
11165 Set luma maximum difference between pixels to still be considered, must
11166 be a value in the 0.1-100.0 range, default value is 1.0.
11168 @item chroma_radius, cr
11169 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
11170 greater value will result in a more blurred image, and in slower
11173 @item chroma_pre_filter_radius, cpfr
11174 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
11176 @item chroma_strength, cs
11177 Set chroma maximum difference between pixels to still be considered,
11178 must be a value in the 0.1-100.0 range.
11181 Each chroma option value, if not explicitly specified, is set to the
11182 corresponding luma option value.
11187 Scale (resize) the input video, using the libswscale library.
11189 The scale filter forces the output display aspect ratio to be the same
11190 of the input, by changing the output sample aspect ratio.
11192 If the input image format is different from the format requested by
11193 the next filter, the scale filter will convert the input to the
11196 @subsection Options
11197 The filter accepts the following options, or any of the options
11198 supported by the libswscale scaler.
11200 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
11201 the complete list of scaler options.
11206 Set the output video dimension expression. Default value is the input
11209 If the value is 0, the input width is used for the output.
11211 If one of the values is -1, the scale filter will use a value that
11212 maintains the aspect ratio of the input image, calculated from the
11213 other specified dimension. If both of them are -1, the input size is
11216 If one of the values is -n with n > 1, the scale filter will also use a value
11217 that maintains the aspect ratio of the input image, calculated from the other
11218 specified dimension. After that it will, however, make sure that the calculated
11219 dimension is divisible by n and adjust the value if necessary.
11221 See below for the list of accepted constants for use in the dimension
11225 Specify when to evaluate @var{width} and @var{height} expression. It accepts the following values:
11229 Only evaluate expressions once during the filter initialization or when a command is processed.
11232 Evaluate expressions for each incoming frame.
11236 Default value is @samp{init}.
11240 Set the interlacing mode. It accepts the following values:
11244 Force interlaced aware scaling.
11247 Do not apply interlaced scaling.
11250 Select interlaced aware scaling depending on whether the source frames
11251 are flagged as interlaced or not.
11254 Default value is @samp{0}.
11257 Set libswscale scaling flags. See
11258 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
11259 complete list of values. If not explicitly specified the filter applies
11263 @item param0, param1
11264 Set libswscale input parameters for scaling algorithms that need them. See
11265 @ref{sws_params,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
11266 complete documentation. If not explicitly specified the filter applies
11272 Set the video size. For the syntax of this option, check the
11273 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11275 @item in_color_matrix
11276 @item out_color_matrix
11277 Set in/output YCbCr color space type.
11279 This allows the autodetected value to be overridden as well as allows forcing
11280 a specific value used for the output and encoder.
11282 If not specified, the color space type depends on the pixel format.
11288 Choose automatically.
11291 Format conforming to International Telecommunication Union (ITU)
11292 Recommendation BT.709.
11295 Set color space conforming to the United States Federal Communications
11296 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
11299 Set color space conforming to:
11303 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
11306 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
11309 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
11314 Set color space conforming to SMPTE ST 240:1999.
11319 Set in/output YCbCr sample range.
11321 This allows the autodetected value to be overridden as well as allows forcing
11322 a specific value used for the output and encoder. If not specified, the
11323 range depends on the pixel format. Possible values:
11327 Choose automatically.
11330 Set full range (0-255 in case of 8-bit luma).
11333 Set "MPEG" range (16-235 in case of 8-bit luma).
11336 @item force_original_aspect_ratio
11337 Enable decreasing or increasing output video width or height if necessary to
11338 keep the original aspect ratio. Possible values:
11342 Scale the video as specified and disable this feature.
11345 The output video dimensions will automatically be decreased if needed.
11348 The output video dimensions will automatically be increased if needed.
11352 One useful instance of this option is that when you know a specific device's
11353 maximum allowed resolution, you can use this to limit the output video to
11354 that, while retaining the aspect ratio. For example, device A allows
11355 1280x720 playback, and your video is 1920x800. Using this option (set it to
11356 decrease) and specifying 1280x720 to the command line makes the output
11359 Please note that this is a different thing than specifying -1 for @option{w}
11360 or @option{h}, you still need to specify the output resolution for this option
11365 The values of the @option{w} and @option{h} options are expressions
11366 containing the following constants:
11371 The input width and height
11375 These are the same as @var{in_w} and @var{in_h}.
11379 The output (scaled) width and height
11383 These are the same as @var{out_w} and @var{out_h}
11386 The same as @var{iw} / @var{ih}
11389 input sample aspect ratio
11392 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
11396 horizontal and vertical input chroma subsample values. For example for the
11397 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11401 horizontal and vertical output chroma subsample values. For example for the
11402 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11405 @subsection Examples
11409 Scale the input video to a size of 200x100
11414 This is equivalent to:
11425 Specify a size abbreviation for the output size:
11430 which can also be written as:
11436 Scale the input to 2x:
11438 scale=w=2*iw:h=2*ih
11442 The above is the same as:
11444 scale=2*in_w:2*in_h
11448 Scale the input to 2x with forced interlaced scaling:
11450 scale=2*iw:2*ih:interl=1
11454 Scale the input to half size:
11456 scale=w=iw/2:h=ih/2
11460 Increase the width, and set the height to the same size:
11466 Seek Greek harmony:
11473 Increase the height, and set the width to 3/2 of the height:
11475 scale=w=3/2*oh:h=3/5*ih
11479 Increase the size, making the size a multiple of the chroma
11482 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
11486 Increase the width to a maximum of 500 pixels,
11487 keeping the same aspect ratio as the input:
11489 scale=w='min(500\, iw*3/2):h=-1'
11493 @subsection Commands
11495 This filter supports the following commands:
11499 Set the output video dimension expression.
11500 The command accepts the same syntax of the corresponding option.
11502 If the specified expression is not valid, it is kept at its current
11508 Scale (resize) the input video, based on a reference video.
11510 See the scale filter for available options, scale2ref supports the same but
11511 uses the reference video instead of the main input as basis.
11513 @subsection Examples
11517 Scale a subtitle stream to match the main video in size before overlaying
11519 'scale2ref[b][a];[a][b]overlay'
11523 @anchor{selectivecolor}
11524 @section selectivecolor
11526 Adjust cyan, magenta, yellow and black (CMYK) to certain ranges of colors (such
11527 as "reds", "yellows", "greens", "cyans", ...). The adjustment range is defined
11528 by the "purity" of the color (that is, how saturated it already is).
11530 This filter is similar to the Adobe Photoshop Selective Color tool.
11532 The filter accepts the following options:
11535 @item correction_method
11536 Select color correction method.
11538 Available values are:
11541 Specified adjustments are applied "as-is" (added/subtracted to original pixel
11544 Specified adjustments are relative to the original component value.
11546 Default is @code{absolute}.
11548 Adjustments for red pixels (pixels where the red component is the maximum)
11550 Adjustments for yellow pixels (pixels where the blue component is the minimum)
11552 Adjustments for green pixels (pixels where the green component is the maximum)
11554 Adjustments for cyan pixels (pixels where the red component is the minimum)
11556 Adjustments for blue pixels (pixels where the blue component is the maximum)
11558 Adjustments for magenta pixels (pixels where the green component is the minimum)
11560 Adjustments for white pixels (pixels where all components are greater than 128)
11562 Adjustments for all pixels except pure black and pure white
11564 Adjustments for black pixels (pixels where all components are lesser than 128)
11566 Specify a Photoshop selective color file (@code{.asv}) to import the settings from.
11569 All the adjustment settings (@option{reds}, @option{yellows}, ...) accept up to
11570 4 space separated floating point adjustment values in the [-1,1] range,
11571 respectively to adjust the amount of cyan, magenta, yellow and black for the
11572 pixels of its range.
11574 @subsection Examples
11578 Increase cyan by 50% and reduce yellow by 33% in every green areas, and
11579 increase magenta by 27% in blue areas:
11581 selectivecolor=greens=.5 0 -.33 0:blues=0 .27
11585 Use a Photoshop selective color preset:
11587 selectivecolor=psfile=MySelectiveColorPresets/Misty.asv
11591 @section separatefields
11593 The @code{separatefields} takes a frame-based video input and splits
11594 each frame into its components fields, producing a new half height clip
11595 with twice the frame rate and twice the frame count.
11597 This filter use field-dominance information in frame to decide which
11598 of each pair of fields to place first in the output.
11599 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
11601 @section setdar, setsar
11603 The @code{setdar} filter sets the Display Aspect Ratio for the filter
11606 This is done by changing the specified Sample (aka Pixel) Aspect
11607 Ratio, according to the following equation:
11609 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
11612 Keep in mind that the @code{setdar} filter does not modify the pixel
11613 dimensions of the video frame. Also, the display aspect ratio set by
11614 this filter may be changed by later filters in the filterchain,
11615 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
11618 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
11619 the filter output video.
11621 Note that as a consequence of the application of this filter, the
11622 output display aspect ratio will change according to the equation
11625 Keep in mind that the sample aspect ratio set by the @code{setsar}
11626 filter may be changed by later filters in the filterchain, e.g. if
11627 another "setsar" or a "setdar" filter is applied.
11629 It accepts the following parameters:
11632 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
11633 Set the aspect ratio used by the filter.
11635 The parameter can be a floating point number string, an expression, or
11636 a string of the form @var{num}:@var{den}, where @var{num} and
11637 @var{den} are the numerator and denominator of the aspect ratio. If
11638 the parameter is not specified, it is assumed the value "0".
11639 In case the form "@var{num}:@var{den}" is used, the @code{:} character
11643 Set the maximum integer value to use for expressing numerator and
11644 denominator when reducing the expressed aspect ratio to a rational.
11645 Default value is @code{100}.
11649 The parameter @var{sar} is an expression containing
11650 the following constants:
11654 These are approximated values for the mathematical constants e
11655 (Euler's number), pi (Greek pi), and phi (the golden ratio).
11658 The input width and height.
11661 These are the same as @var{w} / @var{h}.
11664 The input sample aspect ratio.
11667 The input display aspect ratio. It is the same as
11668 (@var{w} / @var{h}) * @var{sar}.
11671 Horizontal and vertical chroma subsample values. For example, for the
11672 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11675 @subsection Examples
11680 To change the display aspect ratio to 16:9, specify one of the following:
11687 To change the sample aspect ratio to 10:11, specify:
11693 To set a display aspect ratio of 16:9, and specify a maximum integer value of
11694 1000 in the aspect ratio reduction, use the command:
11696 setdar=ratio=16/9:max=1000
11704 Force field for the output video frame.
11706 The @code{setfield} filter marks the interlace type field for the
11707 output frames. It does not change the input frame, but only sets the
11708 corresponding property, which affects how the frame is treated by
11709 following filters (e.g. @code{fieldorder} or @code{yadif}).
11711 The filter accepts the following options:
11716 Available values are:
11720 Keep the same field property.
11723 Mark the frame as bottom-field-first.
11726 Mark the frame as top-field-first.
11729 Mark the frame as progressive.
11735 Show a line containing various information for each input video frame.
11736 The input video is not modified.
11738 The shown line contains a sequence of key/value pairs of the form
11739 @var{key}:@var{value}.
11741 The following values are shown in the output:
11745 The (sequential) number of the input frame, starting from 0.
11748 The Presentation TimeStamp of the input frame, expressed as a number of
11749 time base units. The time base unit depends on the filter input pad.
11752 The Presentation TimeStamp of the input frame, expressed as a number of
11756 The position of the frame in the input stream, or -1 if this information is
11757 unavailable and/or meaningless (for example in case of synthetic video).
11760 The pixel format name.
11763 The sample aspect ratio of the input frame, expressed in the form
11764 @var{num}/@var{den}.
11767 The size of the input frame. For the syntax of this option, check the
11768 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11771 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
11772 for bottom field first).
11775 This is 1 if the frame is a key frame, 0 otherwise.
11778 The picture type of the input frame ("I" for an I-frame, "P" for a
11779 P-frame, "B" for a B-frame, or "?" for an unknown type).
11780 Also refer to the documentation of the @code{AVPictureType} enum and of
11781 the @code{av_get_picture_type_char} function defined in
11782 @file{libavutil/avutil.h}.
11785 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
11787 @item plane_checksum
11788 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
11789 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
11792 @section showpalette
11794 Displays the 256 colors palette of each frame. This filter is only relevant for
11795 @var{pal8} pixel format frames.
11797 It accepts the following option:
11801 Set the size of the box used to represent one palette color entry. Default is
11802 @code{30} (for a @code{30x30} pixel box).
11805 @section shuffleframes
11807 Reorder and/or duplicate video frames.
11809 It accepts the following parameters:
11813 Set the destination indexes of input frames.
11814 This is space or '|' separated list of indexes that maps input frames to output
11815 frames. Number of indexes also sets maximal value that each index may have.
11818 The first frame has the index 0. The default is to keep the input unchanged.
11820 Swap second and third frame of every three frames of the input:
11822 ffmpeg -i INPUT -vf "shuffleframes=0 2 1" OUTPUT
11825 @section shuffleplanes
11827 Reorder and/or duplicate video planes.
11829 It accepts the following parameters:
11834 The index of the input plane to be used as the first output plane.
11837 The index of the input plane to be used as the second output plane.
11840 The index of the input plane to be used as the third output plane.
11843 The index of the input plane to be used as the fourth output plane.
11847 The first plane has the index 0. The default is to keep the input unchanged.
11849 Swap the second and third planes of the input:
11851 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
11854 @anchor{signalstats}
11855 @section signalstats
11856 Evaluate various visual metrics that assist in determining issues associated
11857 with the digitization of analog video media.
11859 By default the filter will log these metadata values:
11863 Display the minimal Y value contained within the input frame. Expressed in
11867 Display the Y value at the 10% percentile within the input frame. Expressed in
11871 Display the average Y value within the input frame. Expressed in range of
11875 Display the Y value at the 90% percentile within the input frame. Expressed in
11879 Display the maximum Y value contained within the input frame. Expressed in
11883 Display the minimal U value contained within the input frame. Expressed in
11887 Display the U value at the 10% percentile within the input frame. Expressed in
11891 Display the average U value within the input frame. Expressed in range of
11895 Display the U value at the 90% percentile within the input frame. Expressed in
11899 Display the maximum U value contained within the input frame. Expressed in
11903 Display the minimal V value contained within the input frame. Expressed in
11907 Display the V value at the 10% percentile within the input frame. Expressed in
11911 Display the average V value within the input frame. Expressed in range of
11915 Display the V value at the 90% percentile within the input frame. Expressed in
11919 Display the maximum V value contained within the input frame. Expressed in
11923 Display the minimal saturation value contained within the input frame.
11924 Expressed in range of [0-~181.02].
11927 Display the saturation value at the 10% percentile within the input frame.
11928 Expressed in range of [0-~181.02].
11931 Display the average saturation value within the input frame. Expressed in range
11935 Display the saturation value at the 90% percentile within the input frame.
11936 Expressed in range of [0-~181.02].
11939 Display the maximum saturation value contained within the input frame.
11940 Expressed in range of [0-~181.02].
11943 Display the median value for hue within the input frame. Expressed in range of
11947 Display the average value for hue within the input frame. Expressed in range of
11951 Display the average of sample value difference between all values of the Y
11952 plane in the current frame and corresponding values of the previous input frame.
11953 Expressed in range of [0-255].
11956 Display the average of sample value difference between all values of the U
11957 plane in the current frame and corresponding values of the previous input frame.
11958 Expressed in range of [0-255].
11961 Display the average of sample value difference between all values of the V
11962 plane in the current frame and corresponding values of the previous input frame.
11963 Expressed in range of [0-255].
11966 The filter accepts the following options:
11972 @option{stat} specify an additional form of image analysis.
11973 @option{out} output video with the specified type of pixel highlighted.
11975 Both options accept the following values:
11979 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
11980 unlike the neighboring pixels of the same field. Examples of temporal outliers
11981 include the results of video dropouts, head clogs, or tape tracking issues.
11984 Identify @var{vertical line repetition}. Vertical line repetition includes
11985 similar rows of pixels within a frame. In born-digital video vertical line
11986 repetition is common, but this pattern is uncommon in video digitized from an
11987 analog source. When it occurs in video that results from the digitization of an
11988 analog source it can indicate concealment from a dropout compensator.
11991 Identify pixels that fall outside of legal broadcast range.
11995 Set the highlight color for the @option{out} option. The default color is
11999 @subsection Examples
12003 Output data of various video metrics:
12005 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
12009 Output specific data about the minimum and maximum values of the Y plane per frame:
12011 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
12015 Playback video while highlighting pixels that are outside of broadcast range in red.
12017 ffplay example.mov -vf signalstats="out=brng:color=red"
12021 Playback video with signalstats metadata drawn over the frame.
12023 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
12026 The contents of signalstat_drawtext.txt used in the command are:
12029 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
12030 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
12031 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
12032 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
12040 Blur the input video without impacting the outlines.
12042 It accepts the following options:
12045 @item luma_radius, lr
12046 Set the luma radius. The option value must be a float number in
12047 the range [0.1,5.0] that specifies the variance of the gaussian filter
12048 used to blur the image (slower if larger). Default value is 1.0.
12050 @item luma_strength, ls
12051 Set the luma strength. The option value must be a float number
12052 in the range [-1.0,1.0] that configures the blurring. A value included
12053 in [0.0,1.0] will blur the image whereas a value included in
12054 [-1.0,0.0] will sharpen the image. Default value is 1.0.
12056 @item luma_threshold, lt
12057 Set the luma threshold used as a coefficient to determine
12058 whether a pixel should be blurred or not. The option value must be an
12059 integer in the range [-30,30]. A value of 0 will filter all the image,
12060 a value included in [0,30] will filter flat areas and a value included
12061 in [-30,0] will filter edges. Default value is 0.
12063 @item chroma_radius, cr
12064 Set the chroma radius. The option value must be a float number in
12065 the range [0.1,5.0] that specifies the variance of the gaussian filter
12066 used to blur the image (slower if larger). Default value is 1.0.
12068 @item chroma_strength, cs
12069 Set the chroma strength. The option value must be a float number
12070 in the range [-1.0,1.0] that configures the blurring. A value included
12071 in [0.0,1.0] will blur the image whereas a value included in
12072 [-1.0,0.0] will sharpen the image. Default value is 1.0.
12074 @item chroma_threshold, ct
12075 Set the chroma threshold used as a coefficient to determine
12076 whether a pixel should be blurred or not. The option value must be an
12077 integer in the range [-30,30]. A value of 0 will filter all the image,
12078 a value included in [0,30] will filter flat areas and a value included
12079 in [-30,0] will filter edges. Default value is 0.
12082 If a chroma option is not explicitly set, the corresponding luma value
12087 Obtain the SSIM (Structural SImilarity Metric) between two input videos.
12089 This filter takes in input two input videos, the first input is
12090 considered the "main" source and is passed unchanged to the
12091 output. The second input is used as a "reference" video for computing
12094 Both video inputs must have the same resolution and pixel format for
12095 this filter to work correctly. Also it assumes that both inputs
12096 have the same number of frames, which are compared one by one.
12098 The filter stores the calculated SSIM of each frame.
12100 The description of the accepted parameters follows.
12103 @item stats_file, f
12104 If specified the filter will use the named file to save the SSIM of
12105 each individual frame. When filename equals "-" the data is sent to
12109 The file printed if @var{stats_file} is selected, contains a sequence of
12110 key/value pairs of the form @var{key}:@var{value} for each compared
12113 A description of each shown parameter follows:
12117 sequential number of the input frame, starting from 1
12119 @item Y, U, V, R, G, B
12120 SSIM of the compared frames for the component specified by the suffix.
12123 SSIM of the compared frames for the whole frame.
12126 Same as above but in dB representation.
12131 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
12132 [main][ref] ssim="stats_file=stats.log" [out]
12135 On this example the input file being processed is compared with the
12136 reference file @file{ref_movie.mpg}. The SSIM of each individual frame
12137 is stored in @file{stats.log}.
12139 Another example with both psnr and ssim at same time:
12141 ffmpeg -i main.mpg -i ref.mpg -lavfi "ssim;[0:v][1:v]psnr" -f null -
12146 Convert between different stereoscopic image formats.
12148 The filters accept the following options:
12152 Set stereoscopic image format of input.
12154 Available values for input image formats are:
12157 side by side parallel (left eye left, right eye right)
12160 side by side crosseye (right eye left, left eye right)
12163 side by side parallel with half width resolution
12164 (left eye left, right eye right)
12167 side by side crosseye with half width resolution
12168 (right eye left, left eye right)
12171 above-below (left eye above, right eye below)
12174 above-below (right eye above, left eye below)
12177 above-below with half height resolution
12178 (left eye above, right eye below)
12181 above-below with half height resolution
12182 (right eye above, left eye below)
12185 alternating frames (left eye first, right eye second)
12188 alternating frames (right eye first, left eye second)
12191 interleaved rows (left eye has top row, right eye starts on next row)
12194 interleaved rows (right eye has top row, left eye starts on next row)
12197 interleaved columns, left eye first
12200 interleaved columns, right eye first
12202 Default value is @samp{sbsl}.
12206 Set stereoscopic image format of output.
12210 side by side parallel (left eye left, right eye right)
12213 side by side crosseye (right eye left, left eye right)
12216 side by side parallel with half width resolution
12217 (left eye left, right eye right)
12220 side by side crosseye with half width resolution
12221 (right eye left, left eye right)
12224 above-below (left eye above, right eye below)
12227 above-below (right eye above, left eye below)
12230 above-below with half height resolution
12231 (left eye above, right eye below)
12234 above-below with half height resolution
12235 (right eye above, left eye below)
12238 alternating frames (left eye first, right eye second)
12241 alternating frames (right eye first, left eye second)
12244 interleaved rows (left eye has top row, right eye starts on next row)
12247 interleaved rows (right eye has top row, left eye starts on next row)
12250 anaglyph red/blue gray
12251 (red filter on left eye, blue filter on right eye)
12254 anaglyph red/green gray
12255 (red filter on left eye, green filter on right eye)
12258 anaglyph red/cyan gray
12259 (red filter on left eye, cyan filter on right eye)
12262 anaglyph red/cyan half colored
12263 (red filter on left eye, cyan filter on right eye)
12266 anaglyph red/cyan color
12267 (red filter on left eye, cyan filter on right eye)
12270 anaglyph red/cyan color optimized with the least squares projection of dubois
12271 (red filter on left eye, cyan filter on right eye)
12274 anaglyph green/magenta gray
12275 (green filter on left eye, magenta filter on right eye)
12278 anaglyph green/magenta half colored
12279 (green filter on left eye, magenta filter on right eye)
12282 anaglyph green/magenta colored
12283 (green filter on left eye, magenta filter on right eye)
12286 anaglyph green/magenta color optimized with the least squares projection of dubois
12287 (green filter on left eye, magenta filter on right eye)
12290 anaglyph yellow/blue gray
12291 (yellow filter on left eye, blue filter on right eye)
12294 anaglyph yellow/blue half colored
12295 (yellow filter on left eye, blue filter on right eye)
12298 anaglyph yellow/blue colored
12299 (yellow filter on left eye, blue filter on right eye)
12302 anaglyph yellow/blue color optimized with the least squares projection of dubois
12303 (yellow filter on left eye, blue filter on right eye)
12306 mono output (left eye only)
12309 mono output (right eye only)
12312 checkerboard, left eye first
12315 checkerboard, right eye first
12318 interleaved columns, left eye first
12321 interleaved columns, right eye first
12324 Default value is @samp{arcd}.
12327 @subsection Examples
12331 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
12337 Convert input video from above below (left eye above, right eye below) to side by side crosseye.
12343 @section streamselect, astreamselect
12344 Select video or audio streams.
12346 The filter accepts the following options:
12350 Set number of inputs. Default is 2.
12353 Set input indexes to remap to outputs.
12356 @subsection Commands
12358 The @code{streamselect} and @code{astreamselect} filter supports the following
12363 Set input indexes to remap to outputs.
12366 @subsection Examples
12370 Select first 5 seconds 1st stream and rest of time 2nd stream:
12372 sendcmd='5.0 streamselect map 1',streamselect=inputs=2:map=0
12376 Same as above, but for audio:
12378 asendcmd='5.0 astreamselect map 1',astreamselect=inputs=2:map=0
12385 Apply a simple postprocessing filter that compresses and decompresses the image
12386 at several (or - in the case of @option{quality} level @code{6} - all) shifts
12387 and average the results.
12389 The filter accepts the following options:
12393 Set quality. This option defines the number of levels for averaging. It accepts
12394 an integer in the range 0-6. If set to @code{0}, the filter will have no
12395 effect. A value of @code{6} means the higher quality. For each increment of
12396 that value the speed drops by a factor of approximately 2. Default value is
12400 Force a constant quantization parameter. If not set, the filter will use the QP
12401 from the video stream (if available).
12404 Set thresholding mode. Available modes are:
12408 Set hard thresholding (default).
12410 Set soft thresholding (better de-ringing effect, but likely blurrier).
12413 @item use_bframe_qp
12414 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
12415 option may cause flicker since the B-Frames have often larger QP. Default is
12416 @code{0} (not enabled).
12422 Draw subtitles on top of input video using the libass library.
12424 To enable compilation of this filter you need to configure FFmpeg with
12425 @code{--enable-libass}. This filter also requires a build with libavcodec and
12426 libavformat to convert the passed subtitles file to ASS (Advanced Substation
12427 Alpha) subtitles format.
12429 The filter accepts the following options:
12433 Set the filename of the subtitle file to read. It must be specified.
12435 @item original_size
12436 Specify the size of the original video, the video for which the ASS file
12437 was composed. For the syntax of this option, check the
12438 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12439 Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
12440 correctly scale the fonts if the aspect ratio has been changed.
12443 Set a directory path containing fonts that can be used by the filter.
12444 These fonts will be used in addition to whatever the font provider uses.
12447 Set subtitles input character encoding. @code{subtitles} filter only. Only
12448 useful if not UTF-8.
12450 @item stream_index, si
12451 Set subtitles stream index. @code{subtitles} filter only.
12454 Override default style or script info parameters of the subtitles. It accepts a
12455 string containing ASS style format @code{KEY=VALUE} couples separated by ",".
12458 If the first key is not specified, it is assumed that the first value
12459 specifies the @option{filename}.
12461 For example, to render the file @file{sub.srt} on top of the input
12462 video, use the command:
12467 which is equivalent to:
12469 subtitles=filename=sub.srt
12472 To render the default subtitles stream from file @file{video.mkv}, use:
12474 subtitles=video.mkv
12477 To render the second subtitles stream from that file, use:
12479 subtitles=video.mkv:si=1
12482 To make the subtitles stream from @file{sub.srt} appear in transparent green
12483 @code{DejaVu Serif}, use:
12485 subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'
12488 @section super2xsai
12490 Scale the input by 2x and smooth using the Super2xSaI (Scale and
12491 Interpolate) pixel art scaling algorithm.
12493 Useful for enlarging pixel art images without reducing sharpness.
12497 Swap two rectangular objects in video.
12499 This filter accepts the following options:
12509 Set 1st rect x coordinate.
12512 Set 1st rect y coordinate.
12515 Set 2nd rect x coordinate.
12518 Set 2nd rect y coordinate.
12520 All expressions are evaluated once for each frame.
12523 The all options are expressions containing the following constants:
12528 The input width and height.
12531 same as @var{w} / @var{h}
12534 input sample aspect ratio
12537 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
12540 The number of the input frame, starting from 0.
12543 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
12546 the position in the file of the input frame, NAN if unknown
12554 Apply telecine process to the video.
12556 This filter accepts the following options:
12565 The default value is @code{top}.
12569 A string of numbers representing the pulldown pattern you wish to apply.
12570 The default value is @code{23}.
12574 Some typical patterns:
12579 24p: 2332 (preferred)
12586 24p: 222222222223 ("Euro pulldown")
12592 Select the most representative frame in a given sequence of consecutive frames.
12594 The filter accepts the following options:
12598 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
12599 will pick one of them, and then handle the next batch of @var{n} frames until
12600 the end. Default is @code{100}.
12603 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
12604 value will result in a higher memory usage, so a high value is not recommended.
12606 @subsection Examples
12610 Extract one picture each 50 frames:
12616 Complete example of a thumbnail creation with @command{ffmpeg}:
12618 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
12624 Tile several successive frames together.
12626 The filter accepts the following options:
12631 Set the grid size (i.e. the number of lines and columns). For the syntax of
12632 this option, check the
12633 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12636 Set the maximum number of frames to render in the given area. It must be less
12637 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
12638 the area will be used.
12641 Set the outer border margin in pixels.
12644 Set the inner border thickness (i.e. the number of pixels between frames). For
12645 more advanced padding options (such as having different values for the edges),
12646 refer to the pad video filter.
12649 Specify the color of the unused area. For the syntax of this option, check the
12650 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
12654 @subsection Examples
12658 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
12660 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
12662 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
12663 duplicating each output frame to accommodate the originally detected frame
12667 Display @code{5} pictures in an area of @code{3x2} frames,
12668 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
12669 mixed flat and named options:
12671 tile=3x2:nb_frames=5:padding=7:margin=2
12675 @section tinterlace
12677 Perform various types of temporal field interlacing.
12679 Frames are counted starting from 1, so the first input frame is
12682 The filter accepts the following options:
12687 Specify the mode of the interlacing. This option can also be specified
12688 as a value alone. See below for a list of values for this option.
12690 Available values are:
12694 Move odd frames into the upper field, even into the lower field,
12695 generating a double height frame at half frame rate.
12699 Frame 1 Frame 2 Frame 3 Frame 4
12701 11111 22222 33333 44444
12702 11111 22222 33333 44444
12703 11111 22222 33333 44444
12704 11111 22222 33333 44444
12718 Only output odd frames, even frames are dropped, generating a frame with
12719 unchanged height at half frame rate.
12724 Frame 1 Frame 2 Frame 3 Frame 4
12726 11111 22222 33333 44444
12727 11111 22222 33333 44444
12728 11111 22222 33333 44444
12729 11111 22222 33333 44444
12739 Only output even frames, odd frames are dropped, generating a frame with
12740 unchanged height at half frame rate.
12745 Frame 1 Frame 2 Frame 3 Frame 4
12747 11111 22222 33333 44444
12748 11111 22222 33333 44444
12749 11111 22222 33333 44444
12750 11111 22222 33333 44444
12760 Expand each frame to full height, but pad alternate lines with black,
12761 generating a frame with double height at the same input frame rate.
12766 Frame 1 Frame 2 Frame 3 Frame 4
12768 11111 22222 33333 44444
12769 11111 22222 33333 44444
12770 11111 22222 33333 44444
12771 11111 22222 33333 44444
12774 11111 ..... 33333 .....
12775 ..... 22222 ..... 44444
12776 11111 ..... 33333 .....
12777 ..... 22222 ..... 44444
12778 11111 ..... 33333 .....
12779 ..... 22222 ..... 44444
12780 11111 ..... 33333 .....
12781 ..... 22222 ..... 44444
12785 @item interleave_top, 4
12786 Interleave the upper field from odd frames with the lower field from
12787 even frames, generating a frame with unchanged height at half frame rate.
12792 Frame 1 Frame 2 Frame 3 Frame 4
12794 11111<- 22222 33333<- 44444
12795 11111 22222<- 33333 44444<-
12796 11111<- 22222 33333<- 44444
12797 11111 22222<- 33333 44444<-
12807 @item interleave_bottom, 5
12808 Interleave the lower field from odd frames with the upper field from
12809 even frames, generating a frame with unchanged height at half frame rate.
12814 Frame 1 Frame 2 Frame 3 Frame 4
12816 11111 22222<- 33333 44444<-
12817 11111<- 22222 33333<- 44444
12818 11111 22222<- 33333 44444<-
12819 11111<- 22222 33333<- 44444
12829 @item interlacex2, 6
12830 Double frame rate with unchanged height. Frames are inserted each
12831 containing the second temporal field from the previous input frame and
12832 the first temporal field from the next input frame. This mode relies on
12833 the top_field_first flag. Useful for interlaced video displays with no
12834 field synchronisation.
12839 Frame 1 Frame 2 Frame 3 Frame 4
12841 11111 22222 33333 44444
12842 11111 22222 33333 44444
12843 11111 22222 33333 44444
12844 11111 22222 33333 44444
12847 11111 22222 22222 33333 33333 44444 44444
12848 11111 11111 22222 22222 33333 33333 44444
12849 11111 22222 22222 33333 33333 44444 44444
12850 11111 11111 22222 22222 33333 33333 44444
12855 Move odd frames into the upper field, even into the lower field,
12856 generating a double height frame at same frame rate.
12861 Frame 1 Frame 2 Frame 3 Frame 4
12863 11111 22222 33333 44444
12864 11111 22222 33333 44444
12865 11111 22222 33333 44444
12866 11111 22222 33333 44444
12869 11111 33333 33333 55555
12870 22222 22222 44444 44444
12871 11111 33333 33333 55555
12872 22222 22222 44444 44444
12873 11111 33333 33333 55555
12874 22222 22222 44444 44444
12875 11111 33333 33333 55555
12876 22222 22222 44444 44444
12881 Numeric values are deprecated but are accepted for backward
12882 compatibility reasons.
12884 Default mode is @code{merge}.
12887 Specify flags influencing the filter process.
12889 Available value for @var{flags} is:
12892 @item low_pass_filter, vlfp
12893 Enable vertical low-pass filtering in the filter.
12894 Vertical low-pass filtering is required when creating an interlaced
12895 destination from a progressive source which contains high-frequency
12896 vertical detail. Filtering will reduce interlace 'twitter' and Moire
12899 Vertical low-pass filtering can only be enabled for @option{mode}
12900 @var{interleave_top} and @var{interleave_bottom}.
12907 Transpose rows with columns in the input video and optionally flip it.
12909 It accepts the following parameters:
12914 Specify the transposition direction.
12916 Can assume the following values:
12918 @item 0, 4, cclock_flip
12919 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
12927 Rotate by 90 degrees clockwise, that is:
12935 Rotate by 90 degrees counterclockwise, that is:
12942 @item 3, 7, clock_flip
12943 Rotate by 90 degrees clockwise and vertically flip, that is:
12951 For values between 4-7, the transposition is only done if the input
12952 video geometry is portrait and not landscape. These values are
12953 deprecated, the @code{passthrough} option should be used instead.
12955 Numerical values are deprecated, and should be dropped in favor of
12956 symbolic constants.
12959 Do not apply the transposition if the input geometry matches the one
12960 specified by the specified value. It accepts the following values:
12963 Always apply transposition.
12965 Preserve portrait geometry (when @var{height} >= @var{width}).
12967 Preserve landscape geometry (when @var{width} >= @var{height}).
12970 Default value is @code{none}.
12973 For example to rotate by 90 degrees clockwise and preserve portrait
12976 transpose=dir=1:passthrough=portrait
12979 The command above can also be specified as:
12981 transpose=1:portrait
12985 Trim the input so that the output contains one continuous subpart of the input.
12987 It accepts the following parameters:
12990 Specify the time of the start of the kept section, i.e. the frame with the
12991 timestamp @var{start} will be the first frame in the output.
12994 Specify the time of the first frame that will be dropped, i.e. the frame
12995 immediately preceding the one with the timestamp @var{end} will be the last
12996 frame in the output.
12999 This is the same as @var{start}, except this option sets the start timestamp
13000 in timebase units instead of seconds.
13003 This is the same as @var{end}, except this option sets the end timestamp
13004 in timebase units instead of seconds.
13007 The maximum duration of the output in seconds.
13010 The number of the first frame that should be passed to the output.
13013 The number of the first frame that should be dropped.
13016 @option{start}, @option{end}, and @option{duration} are expressed as time
13017 duration specifications; see
13018 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
13019 for the accepted syntax.
13021 Note that the first two sets of the start/end options and the @option{duration}
13022 option look at the frame timestamp, while the _frame variants simply count the
13023 frames that pass through the filter. Also note that this filter does not modify
13024 the timestamps. If you wish for the output timestamps to start at zero, insert a
13025 setpts filter after the trim filter.
13027 If multiple start or end options are set, this filter tries to be greedy and
13028 keep all the frames that match at least one of the specified constraints. To keep
13029 only the part that matches all the constraints at once, chain multiple trim
13032 The defaults are such that all the input is kept. So it is possible to set e.g.
13033 just the end values to keep everything before the specified time.
13038 Drop everything except the second minute of input:
13040 ffmpeg -i INPUT -vf trim=60:120
13044 Keep only the first second:
13046 ffmpeg -i INPUT -vf trim=duration=1
13055 Sharpen or blur the input video.
13057 It accepts the following parameters:
13060 @item luma_msize_x, lx
13061 Set the luma matrix horizontal size. It must be an odd integer between
13062 3 and 63. The default value is 5.
13064 @item luma_msize_y, ly
13065 Set the luma matrix vertical size. It must be an odd integer between 3
13066 and 63. The default value is 5.
13068 @item luma_amount, la
13069 Set the luma effect strength. It must be a floating point number, reasonable
13070 values lay between -1.5 and 1.5.
13072 Negative values will blur the input video, while positive values will
13073 sharpen it, a value of zero will disable the effect.
13075 Default value is 1.0.
13077 @item chroma_msize_x, cx
13078 Set the chroma matrix horizontal size. It must be an odd integer
13079 between 3 and 63. The default value is 5.
13081 @item chroma_msize_y, cy
13082 Set the chroma matrix vertical size. It must be an odd integer
13083 between 3 and 63. The default value is 5.
13085 @item chroma_amount, ca
13086 Set the chroma effect strength. It must be a floating point number, reasonable
13087 values lay between -1.5 and 1.5.
13089 Negative values will blur the input video, while positive values will
13090 sharpen it, a value of zero will disable the effect.
13092 Default value is 0.0.
13095 If set to 1, specify using OpenCL capabilities, only available if
13096 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
13100 All parameters are optional and default to the equivalent of the
13101 string '5:5:1.0:5:5:0.0'.
13103 @subsection Examples
13107 Apply strong luma sharpen effect:
13109 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
13113 Apply a strong blur of both luma and chroma parameters:
13115 unsharp=7:7:-2:7:7:-2
13121 Apply ultra slow/simple postprocessing filter that compresses and decompresses
13122 the image at several (or - in the case of @option{quality} level @code{8} - all)
13123 shifts and average the results.
13125 The way this differs from the behavior of spp is that uspp actually encodes &
13126 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
13127 DCT similar to MJPEG.
13129 The filter accepts the following options:
13133 Set quality. This option defines the number of levels for averaging. It accepts
13134 an integer in the range 0-8. If set to @code{0}, the filter will have no
13135 effect. A value of @code{8} means the higher quality. For each increment of
13136 that value the speed drops by a factor of approximately 2. Default value is
13140 Force a constant quantization parameter. If not set, the filter will use the QP
13141 from the video stream (if available).
13144 @section vectorscope
13146 Display 2 color component values in the two dimensional graph (which is called
13149 This filter accepts the following options:
13153 Set vectorscope mode.
13155 It accepts the following values:
13158 Gray values are displayed on graph, higher brightness means more pixels have
13159 same component color value on location in graph. This is the default mode.
13162 Gray values are displayed on graph. Surrounding pixels values which are not
13163 present in video frame are drawn in gradient of 2 color components which are
13164 set by option @code{x} and @code{y}. The 3rd color component is static.
13167 Actual color components values present in video frame are displayed on graph.
13170 Similar as color2 but higher frequency of same values @code{x} and @code{y}
13171 on graph increases value of another color component, which is luminance by
13172 default values of @code{x} and @code{y}.
13175 Actual colors present in video frame are displayed on graph. If two different
13176 colors map to same position on graph then color with higher value of component
13177 not present in graph is picked.
13180 Gray values are displayed on graph. Similar to @code{color} but with 3rd color
13181 component picked from radial gradient.
13185 Set which color component will be represented on X-axis. Default is @code{1}.
13188 Set which color component will be represented on Y-axis. Default is @code{2}.
13191 Set intensity, used by modes: gray, color, color3 and color5 for increasing brightness
13192 of color component which represents frequency of (X, Y) location in graph.
13197 No envelope, this is default.
13200 Instant envelope, even darkest single pixel will be clearly highlighted.
13203 Hold maximum and minimum values presented in graph over time. This way you
13204 can still spot out of range values without constantly looking at vectorscope.
13207 Peak and instant envelope combined together.
13211 Set what kind of graticule to draw.
13219 Set graticule opacity.
13222 Set graticule flags.
13226 Draw graticule for white point.
13229 Draw graticule for black point.
13232 Draw color points short names.
13236 Set background opacity.
13238 @item lthreshold, l
13239 Set low threshold for color component not represented on X or Y axis.
13240 Values lower than this value will be ignored. Default is 0.
13241 Note this value is multiplied with actual max possible value one pixel component
13242 can have. So for 8-bit input and low threshold value of 0.1 actual threshold
13245 @item hthreshold, h
13246 Set high threshold for color component not represented on X or Y axis.
13247 Values higher than this value will be ignored. Default is 1.
13248 Note this value is multiplied with actual max possible value one pixel component
13249 can have. So for 8-bit input and high threshold value of 0.9 actual threshold
13250 is 0.9 * 255 = 230.
13252 @item colorspace, c
13253 Set what kind of colorspace to use when drawing graticule.
13262 @anchor{vidstabdetect}
13263 @section vidstabdetect
13265 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
13266 @ref{vidstabtransform} for pass 2.
13268 This filter generates a file with relative translation and rotation
13269 transform information about subsequent frames, which is then used by
13270 the @ref{vidstabtransform} filter.
13272 To enable compilation of this filter you need to configure FFmpeg with
13273 @code{--enable-libvidstab}.
13275 This filter accepts the following options:
13279 Set the path to the file used to write the transforms information.
13280 Default value is @file{transforms.trf}.
13283 Set how shaky the video is and how quick the camera is. It accepts an
13284 integer in the range 1-10, a value of 1 means little shakiness, a
13285 value of 10 means strong shakiness. Default value is 5.
13288 Set the accuracy of the detection process. It must be a value in the
13289 range 1-15. A value of 1 means low accuracy, a value of 15 means high
13290 accuracy. Default value is 15.
13293 Set stepsize of the search process. The region around minimum is
13294 scanned with 1 pixel resolution. Default value is 6.
13297 Set minimum contrast. Below this value a local measurement field is
13298 discarded. Must be a floating point value in the range 0-1. Default
13302 Set reference frame number for tripod mode.
13304 If enabled, the motion of the frames is compared to a reference frame
13305 in the filtered stream, identified by the specified number. The idea
13306 is to compensate all movements in a more-or-less static scene and keep
13307 the camera view absolutely still.
13309 If set to 0, it is disabled. The frames are counted starting from 1.
13312 Show fields and transforms in the resulting frames. It accepts an
13313 integer in the range 0-2. Default value is 0, which disables any
13317 @subsection Examples
13321 Use default values:
13327 Analyze strongly shaky movie and put the results in file
13328 @file{mytransforms.trf}:
13330 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
13334 Visualize the result of internal transformations in the resulting
13337 vidstabdetect=show=1
13341 Analyze a video with medium shakiness using @command{ffmpeg}:
13343 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
13347 @anchor{vidstabtransform}
13348 @section vidstabtransform
13350 Video stabilization/deshaking: pass 2 of 2,
13351 see @ref{vidstabdetect} for pass 1.
13353 Read a file with transform information for each frame and
13354 apply/compensate them. Together with the @ref{vidstabdetect}
13355 filter this can be used to deshake videos. See also
13356 @url{http://public.hronopik.de/vid.stab}. It is important to also use
13357 the @ref{unsharp} filter, see below.
13359 To enable compilation of this filter you need to configure FFmpeg with
13360 @code{--enable-libvidstab}.
13362 @subsection Options
13366 Set path to the file used to read the transforms. Default value is
13367 @file{transforms.trf}.
13370 Set the number of frames (value*2 + 1) used for lowpass filtering the
13371 camera movements. Default value is 10.
13373 For example a number of 10 means that 21 frames are used (10 in the
13374 past and 10 in the future) to smoothen the motion in the video. A
13375 larger value leads to a smoother video, but limits the acceleration of
13376 the camera (pan/tilt movements). 0 is a special case where a static
13377 camera is simulated.
13380 Set the camera path optimization algorithm.
13382 Accepted values are:
13385 gaussian kernel low-pass filter on camera motion (default)
13387 averaging on transformations
13391 Set maximal number of pixels to translate frames. Default value is -1,
13395 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
13396 value is -1, meaning no limit.
13399 Specify how to deal with borders that may be visible due to movement
13402 Available values are:
13405 keep image information from previous frame (default)
13407 fill the border black
13411 Invert transforms if set to 1. Default value is 0.
13414 Consider transforms as relative to previous frame if set to 1,
13415 absolute if set to 0. Default value is 0.
13418 Set percentage to zoom. A positive value will result in a zoom-in
13419 effect, a negative value in a zoom-out effect. Default value is 0 (no
13423 Set optimal zooming to avoid borders.
13425 Accepted values are:
13430 optimal static zoom value is determined (only very strong movements
13431 will lead to visible borders) (default)
13433 optimal adaptive zoom value is determined (no borders will be
13434 visible), see @option{zoomspeed}
13437 Note that the value given at zoom is added to the one calculated here.
13440 Set percent to zoom maximally each frame (enabled when
13441 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
13445 Specify type of interpolation.
13447 Available values are:
13452 linear only horizontal
13454 linear in both directions (default)
13456 cubic in both directions (slow)
13460 Enable virtual tripod mode if set to 1, which is equivalent to
13461 @code{relative=0:smoothing=0}. Default value is 0.
13463 Use also @code{tripod} option of @ref{vidstabdetect}.
13466 Increase log verbosity if set to 1. Also the detected global motions
13467 are written to the temporary file @file{global_motions.trf}. Default
13471 @subsection Examples
13475 Use @command{ffmpeg} for a typical stabilization with default values:
13477 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
13480 Note the use of the @ref{unsharp} filter which is always recommended.
13483 Zoom in a bit more and load transform data from a given file:
13485 vidstabtransform=zoom=5:input="mytransforms.trf"
13489 Smoothen the video even more:
13491 vidstabtransform=smoothing=30
13497 Flip the input video vertically.
13499 For example, to vertically flip a video with @command{ffmpeg}:
13501 ffmpeg -i in.avi -vf "vflip" out.avi
13507 Make or reverse a natural vignetting effect.
13509 The filter accepts the following options:
13513 Set lens angle expression as a number of radians.
13515 The value is clipped in the @code{[0,PI/2]} range.
13517 Default value: @code{"PI/5"}
13521 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
13525 Set forward/backward mode.
13527 Available modes are:
13530 The larger the distance from the central point, the darker the image becomes.
13533 The larger the distance from the central point, the brighter the image becomes.
13534 This can be used to reverse a vignette effect, though there is no automatic
13535 detection to extract the lens @option{angle} and other settings (yet). It can
13536 also be used to create a burning effect.
13539 Default value is @samp{forward}.
13542 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
13544 It accepts the following values:
13547 Evaluate expressions only once during the filter initialization.
13550 Evaluate expressions for each incoming frame. This is way slower than the
13551 @samp{init} mode since it requires all the scalers to be re-computed, but it
13552 allows advanced dynamic expressions.
13555 Default value is @samp{init}.
13558 Set dithering to reduce the circular banding effects. Default is @code{1}
13562 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
13563 Setting this value to the SAR of the input will make a rectangular vignetting
13564 following the dimensions of the video.
13566 Default is @code{1/1}.
13569 @subsection Expressions
13571 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
13572 following parameters.
13577 input width and height
13580 the number of input frame, starting from 0
13583 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
13584 @var{TB} units, NAN if undefined
13587 frame rate of the input video, NAN if the input frame rate is unknown
13590 the PTS (Presentation TimeStamp) of the filtered video frame,
13591 expressed in seconds, NAN if undefined
13594 time base of the input video
13598 @subsection Examples
13602 Apply simple strong vignetting effect:
13608 Make a flickering vignetting:
13610 vignette='PI/4+random(1)*PI/50':eval=frame
13616 Stack input videos vertically.
13618 All streams must be of same pixel format and of same width.
13620 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
13621 to create same output.
13623 The filter accept the following option:
13627 Set number of input streams. Default is 2.
13630 If set to 1, force the output to terminate when the shortest input
13631 terminates. Default value is 0.
13636 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
13637 Deinterlacing Filter").
13639 Based on the process described by Martin Weston for BBC R&D, and
13640 implemented based on the de-interlace algorithm written by Jim
13641 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
13642 uses filter coefficients calculated by BBC R&D.
13644 There are two sets of filter coefficients, so called "simple":
13645 and "complex". Which set of filter coefficients is used can
13646 be set by passing an optional parameter:
13650 Set the interlacing filter coefficients. Accepts one of the following values:
13654 Simple filter coefficient set.
13656 More-complex filter coefficient set.
13658 Default value is @samp{complex}.
13661 Specify which frames to deinterlace. Accept one of the following values:
13665 Deinterlace all frames,
13667 Only deinterlace frames marked as interlaced.
13670 Default value is @samp{all}.
13674 Video waveform monitor.
13676 The waveform monitor plots color component intensity. By default luminance
13677 only. Each column of the waveform corresponds to a column of pixels in the
13680 It accepts the following options:
13684 Can be either @code{row}, or @code{column}. Default is @code{column}.
13685 In row mode, the graph on the left side represents color component value 0 and
13686 the right side represents value = 255. In column mode, the top side represents
13687 color component value = 0 and bottom side represents value = 255.
13690 Set intensity. Smaller values are useful to find out how many values of the same
13691 luminance are distributed across input rows/columns.
13692 Default value is @code{0.04}. Allowed range is [0, 1].
13695 Set mirroring mode. @code{0} means unmirrored, @code{1} means mirrored.
13696 In mirrored mode, higher values will be represented on the left
13697 side for @code{row} mode and at the top for @code{column} mode. Default is
13698 @code{1} (mirrored).
13702 It accepts the following values:
13705 Presents information identical to that in the @code{parade}, except
13706 that the graphs representing color components are superimposed directly
13709 This display mode makes it easier to spot relative differences or similarities
13710 in overlapping areas of the color components that are supposed to be identical,
13711 such as neutral whites, grays, or blacks.
13714 Display separate graph for the color components side by side in
13715 @code{row} mode or one below the other in @code{column} mode.
13718 Display separate graph for the color components side by side in
13719 @code{column} mode or one below the other in @code{row} mode.
13721 Using this display mode makes it easy to spot color casts in the highlights
13722 and shadows of an image, by comparing the contours of the top and the bottom
13723 graphs of each waveform. Since whites, grays, and blacks are characterized
13724 by exactly equal amounts of red, green, and blue, neutral areas of the picture
13725 should display three waveforms of roughly equal width/height. If not, the
13726 correction is easy to perform by making level adjustments the three waveforms.
13728 Default is @code{stack}.
13730 @item components, c
13731 Set which color components to display. Default is 1, which means only luminance
13732 or red color component if input is in RGB colorspace. If is set for example to
13733 7 it will display all 3 (if) available color components.
13738 No envelope, this is default.
13741 Instant envelope, minimum and maximum values presented in graph will be easily
13742 visible even with small @code{step} value.
13745 Hold minimum and maximum values presented in graph across time. This way you
13746 can still spot out of range values without constantly looking at waveforms.
13749 Peak and instant envelope combined together.
13755 No filtering, this is default.
13758 Luma and chroma combined together.
13761 Similar as above, but shows difference between blue and red chroma.
13764 Displays only chroma.
13767 Displays actual color value on waveform.
13770 Similar as above, but with luma showing frequency of chroma values.
13774 Set which graticule to display.
13778 Do not display graticule.
13781 Display green graticule showing legal broadcast ranges.
13785 Set graticule opacity.
13788 Set graticule flags.
13792 Draw numbers above lines. By default enabled.
13795 Draw dots instead of lines.
13799 Set scale used for displaying graticule.
13806 Default is digital.
13810 Apply the xBR high-quality magnification filter which is designed for pixel
13811 art. It follows a set of edge-detection rules, see
13812 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
13814 It accepts the following option:
13818 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
13819 @code{3xBR} and @code{4} for @code{4xBR}.
13820 Default is @code{3}.
13826 Deinterlace the input video ("yadif" means "yet another deinterlacing
13829 It accepts the following parameters:
13835 The interlacing mode to adopt. It accepts one of the following values:
13838 @item 0, send_frame
13839 Output one frame for each frame.
13840 @item 1, send_field
13841 Output one frame for each field.
13842 @item 2, send_frame_nospatial
13843 Like @code{send_frame}, but it skips the spatial interlacing check.
13844 @item 3, send_field_nospatial
13845 Like @code{send_field}, but it skips the spatial interlacing check.
13848 The default value is @code{send_frame}.
13851 The picture field parity assumed for the input interlaced video. It accepts one
13852 of the following values:
13856 Assume the top field is first.
13858 Assume the bottom field is first.
13860 Enable automatic detection of field parity.
13863 The default value is @code{auto}.
13864 If the interlacing is unknown or the decoder does not export this information,
13865 top field first will be assumed.
13868 Specify which frames to deinterlace. Accept one of the following
13873 Deinterlace all frames.
13874 @item 1, interlaced
13875 Only deinterlace frames marked as interlaced.
13878 The default value is @code{all}.
13883 Apply Zoom & Pan effect.
13885 This filter accepts the following options:
13889 Set the zoom expression. Default is 1.
13893 Set the x and y expression. Default is 0.
13896 Set the duration expression in number of frames.
13897 This sets for how many number of frames effect will last for
13898 single input image.
13901 Set the output image size, default is 'hd720'.
13904 Set the output frame rate, default is '25'.
13907 Each expression can contain the following constants:
13926 Output frame count.
13930 Last calculated 'x' and 'y' position from 'x' and 'y' expression
13931 for current input frame.
13935 'x' and 'y' of last output frame of previous input frame or 0 when there was
13936 not yet such frame (first input frame).
13939 Last calculated zoom from 'z' expression for current input frame.
13942 Last calculated zoom of last output frame of previous input frame.
13945 Number of output frames for current input frame. Calculated from 'd' expression
13946 for each input frame.
13949 number of output frames created for previous input frame
13952 Rational number: input width / input height
13955 sample aspect ratio
13958 display aspect ratio
13962 @subsection Examples
13966 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
13968 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='if(gte(zoom,1.5),x,x+1/a)':y='if(gte(zoom,1.5),y,y+1)':s=640x360
13972 Zoom-in up to 1.5 and pan always at center of picture:
13974 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
13979 Scale (resize) the input video, using the z.lib library:
13980 https://github.com/sekrit-twc/zimg.
13982 The zscale filter forces the output display aspect ratio to be the same
13983 as the input, by changing the output sample aspect ratio.
13985 If the input image format is different from the format requested by
13986 the next filter, the zscale filter will convert the input to the
13989 @subsection Options
13990 The filter accepts the following options.
13995 Set the output video dimension expression. Default value is the input
13998 If the @var{width} or @var{w} is 0, the input width is used for the output.
13999 If the @var{height} or @var{h} is 0, the input height is used for the output.
14001 If one of the values is -1, the zscale filter will use a value that
14002 maintains the aspect ratio of the input image, calculated from the
14003 other specified dimension. If both of them are -1, the input size is
14006 If one of the values is -n with n > 1, the zscale filter will also use a value
14007 that maintains the aspect ratio of the input image, calculated from the other
14008 specified dimension. After that it will, however, make sure that the calculated
14009 dimension is divisible by n and adjust the value if necessary.
14011 See below for the list of accepted constants for use in the dimension
14015 Set the video size. For the syntax of this option, check the
14016 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14019 Set the dither type.
14021 Possible values are:
14026 @item error_diffusion
14032 Set the resize filter type.
14034 Possible values are:
14044 Default is bilinear.
14047 Set the color range.
14049 Possible values are:
14056 Default is same as input.
14059 Set the color primaries.
14061 Possible values are:
14071 Default is same as input.
14074 Set the transfer characteristics.
14076 Possible values are:
14087 Default is same as input.
14090 Set the colorspace matrix.
14092 Possible value are:
14103 Default is same as input.
14106 Set the input color range.
14108 Possible values are:
14115 Default is same as input.
14117 @item primariesin, pin
14118 Set the input color primaries.
14120 Possible values are:
14130 Default is same as input.
14132 @item transferin, tin
14133 Set the input transfer characteristics.
14135 Possible values are:
14146 Default is same as input.
14148 @item matrixin, min
14149 Set the input colorspace matrix.
14151 Possible value are:
14163 The values of the @option{w} and @option{h} options are expressions
14164 containing the following constants:
14169 The input width and height
14173 These are the same as @var{in_w} and @var{in_h}.
14177 The output (scaled) width and height
14181 These are the same as @var{out_w} and @var{out_h}
14184 The same as @var{iw} / @var{ih}
14187 input sample aspect ratio
14190 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
14194 horizontal and vertical input chroma subsample values. For example for the
14195 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
14199 horizontal and vertical output chroma subsample values. For example for the
14200 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
14206 @c man end VIDEO FILTERS
14208 @chapter Video Sources
14209 @c man begin VIDEO SOURCES
14211 Below is a description of the currently available video sources.
14215 Buffer video frames, and make them available to the filter chain.
14217 This source is mainly intended for a programmatic use, in particular
14218 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
14220 It accepts the following parameters:
14225 Specify the size (width and height) of the buffered video frames. For the
14226 syntax of this option, check the
14227 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14230 The input video width.
14233 The input video height.
14236 A string representing the pixel format of the buffered video frames.
14237 It may be a number corresponding to a pixel format, or a pixel format
14241 Specify the timebase assumed by the timestamps of the buffered frames.
14244 Specify the frame rate expected for the video stream.
14246 @item pixel_aspect, sar
14247 The sample (pixel) aspect ratio of the input video.
14250 Specify the optional parameters to be used for the scale filter which
14251 is automatically inserted when an input change is detected in the
14252 input size or format.
14254 @item hw_frames_ctx
14255 When using a hardware pixel format, this should be a reference to an
14256 AVHWFramesContext describing input frames.
14261 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
14264 will instruct the source to accept video frames with size 320x240 and
14265 with format "yuv410p", assuming 1/24 as the timestamps timebase and
14266 square pixels (1:1 sample aspect ratio).
14267 Since the pixel format with name "yuv410p" corresponds to the number 6
14268 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
14269 this example corresponds to:
14271 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
14274 Alternatively, the options can be specified as a flat string, but this
14275 syntax is deprecated:
14277 @var{width}:@var{height}:@var{pix_fmt}:@var{time_base.num}:@var{time_base.den}:@var{pixel_aspect.num}:@var{pixel_aspect.den}[:@var{sws_param}]
14281 Create a pattern generated by an elementary cellular automaton.
14283 The initial state of the cellular automaton can be defined through the
14284 @option{filename}, and @option{pattern} options. If such options are
14285 not specified an initial state is created randomly.
14287 At each new frame a new row in the video is filled with the result of
14288 the cellular automaton next generation. The behavior when the whole
14289 frame is filled is defined by the @option{scroll} option.
14291 This source accepts the following options:
14295 Read the initial cellular automaton state, i.e. the starting row, from
14296 the specified file.
14297 In the file, each non-whitespace character is considered an alive
14298 cell, a newline will terminate the row, and further characters in the
14299 file will be ignored.
14302 Read the initial cellular automaton state, i.e. the starting row, from
14303 the specified string.
14305 Each non-whitespace character in the string is considered an alive
14306 cell, a newline will terminate the row, and further characters in the
14307 string will be ignored.
14310 Set the video rate, that is the number of frames generated per second.
14313 @item random_fill_ratio, ratio
14314 Set the random fill ratio for the initial cellular automaton row. It
14315 is a floating point number value ranging from 0 to 1, defaults to
14318 This option is ignored when a file or a pattern is specified.
14320 @item random_seed, seed
14321 Set the seed for filling randomly the initial row, must be an integer
14322 included between 0 and UINT32_MAX. If not specified, or if explicitly
14323 set to -1, the filter will try to use a good random seed on a best
14327 Set the cellular automaton rule, it is a number ranging from 0 to 255.
14328 Default value is 110.
14331 Set the size of the output video. For the syntax of this option, check the
14332 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14334 If @option{filename} or @option{pattern} is specified, the size is set
14335 by default to the width of the specified initial state row, and the
14336 height is set to @var{width} * PHI.
14338 If @option{size} is set, it must contain the width of the specified
14339 pattern string, and the specified pattern will be centered in the
14342 If a filename or a pattern string is not specified, the size value
14343 defaults to "320x518" (used for a randomly generated initial state).
14346 If set to 1, scroll the output upward when all the rows in the output
14347 have been already filled. If set to 0, the new generated row will be
14348 written over the top row just after the bottom row is filled.
14351 @item start_full, full
14352 If set to 1, completely fill the output with generated rows before
14353 outputting the first frame.
14354 This is the default behavior, for disabling set the value to 0.
14357 If set to 1, stitch the left and right row edges together.
14358 This is the default behavior, for disabling set the value to 0.
14361 @subsection Examples
14365 Read the initial state from @file{pattern}, and specify an output of
14368 cellauto=f=pattern:s=200x400
14372 Generate a random initial row with a width of 200 cells, with a fill
14375 cellauto=ratio=2/3:s=200x200
14379 Create a pattern generated by rule 18 starting by a single alive cell
14380 centered on an initial row with width 100:
14382 cellauto=p=@@:s=100x400:full=0:rule=18
14386 Specify a more elaborated initial pattern:
14388 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
14393 @anchor{coreimagesrc}
14394 @section coreimagesrc
14395 Video source generated on GPU using Apple's CoreImage API on OSX.
14397 This video source is a specialized version of the @ref{coreimage} video filter.
14398 Use a core image generator at the beginning of the applied filterchain to
14399 generate the content.
14401 The coreimagesrc video source accepts the following options:
14403 @item list_generators
14404 List all available generators along with all their respective options as well as
14405 possible minimum and maximum values along with the default values.
14407 list_generators=true
14411 Specify the size of the sourced video. For the syntax of this option, check the
14412 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14413 The default value is @code{320x240}.
14416 Specify the frame rate of the sourced video, as the number of frames
14417 generated per second. It has to be a string in the format
14418 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
14419 number or a valid video frame rate abbreviation. The default value is
14423 Set the sample aspect ratio of the sourced video.
14426 Set the duration of the sourced video. See
14427 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
14428 for the accepted syntax.
14430 If not specified, or the expressed duration is negative, the video is
14431 supposed to be generated forever.
14434 Additionally, all options of the @ref{coreimage} video filter are accepted.
14435 A complete filterchain can be used for further processing of the
14436 generated input without CPU-HOST transfer. See @ref{coreimage} documentation
14437 and examples for details.
14439 @subsection Examples
14444 Use CIQRCodeGenerator to create a QR code for the FFmpeg homepage,
14445 given as complete and escaped command-line for Apple's standard bash shell:
14447 ffmpeg -f lavfi -i coreimagesrc=s=100x100:filter=CIQRCodeGenerator@@inputMessage=https\\\\\://FFmpeg.org/@@inputCorrectionLevel=H -frames:v 1 QRCode.png
14449 This example is equivalent to the QRCode example of @ref{coreimage} without the
14450 need for a nullsrc video source.
14454 @section mandelbrot
14456 Generate a Mandelbrot set fractal, and progressively zoom towards the
14457 point specified with @var{start_x} and @var{start_y}.
14459 This source accepts the following options:
14464 Set the terminal pts value. Default value is 400.
14467 Set the terminal scale value.
14468 Must be a floating point value. Default value is 0.3.
14471 Set the inner coloring mode, that is the algorithm used to draw the
14472 Mandelbrot fractal internal region.
14474 It shall assume one of the following values:
14479 Show time until convergence.
14481 Set color based on point closest to the origin of the iterations.
14486 Default value is @var{mincol}.
14489 Set the bailout value. Default value is 10.0.
14492 Set the maximum of iterations performed by the rendering
14493 algorithm. Default value is 7189.
14496 Set outer coloring mode.
14497 It shall assume one of following values:
14499 @item iteration_count
14500 Set iteration cound mode.
14501 @item normalized_iteration_count
14502 set normalized iteration count mode.
14504 Default value is @var{normalized_iteration_count}.
14507 Set frame rate, expressed as number of frames per second. Default
14511 Set frame size. For the syntax of this option, check the "Video
14512 size" section in the ffmpeg-utils manual. Default value is "640x480".
14515 Set the initial scale value. Default value is 3.0.
14518 Set the initial x position. Must be a floating point value between
14519 -100 and 100. Default value is -0.743643887037158704752191506114774.
14522 Set the initial y position. Must be a floating point value between
14523 -100 and 100. Default value is -0.131825904205311970493132056385139.
14528 Generate various test patterns, as generated by the MPlayer test filter.
14530 The size of the generated video is fixed, and is 256x256.
14531 This source is useful in particular for testing encoding features.
14533 This source accepts the following options:
14538 Specify the frame rate of the sourced video, as the number of frames
14539 generated per second. It has to be a string in the format
14540 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
14541 number or a valid video frame rate abbreviation. The default value is
14545 Set the duration of the sourced video. See
14546 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
14547 for the accepted syntax.
14549 If not specified, or the expressed duration is negative, the video is
14550 supposed to be generated forever.
14554 Set the number or the name of the test to perform. Supported tests are:
14570 Default value is "all", which will cycle through the list of all tests.
14575 mptestsrc=t=dc_luma
14578 will generate a "dc_luma" test pattern.
14580 @section frei0r_src
14582 Provide a frei0r source.
14584 To enable compilation of this filter you need to install the frei0r
14585 header and configure FFmpeg with @code{--enable-frei0r}.
14587 This source accepts the following parameters:
14592 The size of the video to generate. For the syntax of this option, check the
14593 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14596 The framerate of the generated video. It may be a string of the form
14597 @var{num}/@var{den} or a frame rate abbreviation.
14600 The name to the frei0r source to load. For more information regarding frei0r and
14601 how to set the parameters, read the @ref{frei0r} section in the video filters
14604 @item filter_params
14605 A '|'-separated list of parameters to pass to the frei0r source.
14609 For example, to generate a frei0r partik0l source with size 200x200
14610 and frame rate 10 which is overlaid on the overlay filter main input:
14612 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
14617 Generate a life pattern.
14619 This source is based on a generalization of John Conway's life game.
14621 The sourced input represents a life grid, each pixel represents a cell
14622 which can be in one of two possible states, alive or dead. Every cell
14623 interacts with its eight neighbours, which are the cells that are
14624 horizontally, vertically, or diagonally adjacent.
14626 At each interaction the grid evolves according to the adopted rule,
14627 which specifies the number of neighbor alive cells which will make a
14628 cell stay alive or born. The @option{rule} option allows one to specify
14631 This source accepts the following options:
14635 Set the file from which to read the initial grid state. In the file,
14636 each non-whitespace character is considered an alive cell, and newline
14637 is used to delimit the end of each row.
14639 If this option is not specified, the initial grid is generated
14643 Set the video rate, that is the number of frames generated per second.
14646 @item random_fill_ratio, ratio
14647 Set the random fill ratio for the initial random grid. It is a
14648 floating point number value ranging from 0 to 1, defaults to 1/PHI.
14649 It is ignored when a file is specified.
14651 @item random_seed, seed
14652 Set the seed for filling the initial random grid, must be an integer
14653 included between 0 and UINT32_MAX. If not specified, or if explicitly
14654 set to -1, the filter will try to use a good random seed on a best
14660 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
14661 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
14662 @var{NS} specifies the number of alive neighbor cells which make a
14663 live cell stay alive, and @var{NB} the number of alive neighbor cells
14664 which make a dead cell to become alive (i.e. to "born").
14665 "s" and "b" can be used in place of "S" and "B", respectively.
14667 Alternatively a rule can be specified by an 18-bits integer. The 9
14668 high order bits are used to encode the next cell state if it is alive
14669 for each number of neighbor alive cells, the low order bits specify
14670 the rule for "borning" new cells. Higher order bits encode for an
14671 higher number of neighbor cells.
14672 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
14673 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
14675 Default value is "S23/B3", which is the original Conway's game of life
14676 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
14677 cells, and will born a new cell if there are three alive cells around
14681 Set the size of the output video. For the syntax of this option, check the
14682 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14684 If @option{filename} is specified, the size is set by default to the
14685 same size of the input file. If @option{size} is set, it must contain
14686 the size specified in the input file, and the initial grid defined in
14687 that file is centered in the larger resulting area.
14689 If a filename is not specified, the size value defaults to "320x240"
14690 (used for a randomly generated initial grid).
14693 If set to 1, stitch the left and right grid edges together, and the
14694 top and bottom edges also. Defaults to 1.
14697 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
14698 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
14699 value from 0 to 255.
14702 Set the color of living (or new born) cells.
14705 Set the color of dead cells. If @option{mold} is set, this is the first color
14706 used to represent a dead cell.
14709 Set mold color, for definitely dead and moldy cells.
14711 For the syntax of these 3 color options, check the "Color" section in the
14712 ffmpeg-utils manual.
14715 @subsection Examples
14719 Read a grid from @file{pattern}, and center it on a grid of size
14722 life=f=pattern:s=300x300
14726 Generate a random grid of size 200x200, with a fill ratio of 2/3:
14728 life=ratio=2/3:s=200x200
14732 Specify a custom rule for evolving a randomly generated grid:
14738 Full example with slow death effect (mold) using @command{ffplay}:
14740 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
14747 @anchor{haldclutsrc}
14749 @anchor{rgbtestsrc}
14751 @anchor{smptehdbars}
14754 @section allrgb, allyuv, color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc, testsrc2
14756 The @code{allrgb} source returns frames of size 4096x4096 of all rgb colors.
14758 The @code{allyuv} source returns frames of size 4096x4096 of all yuv colors.
14760 The @code{color} source provides an uniformly colored input.
14762 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
14763 @ref{haldclut} filter.
14765 The @code{nullsrc} source returns unprocessed video frames. It is
14766 mainly useful to be employed in analysis / debugging tools, or as the
14767 source for filters which ignore the input data.
14769 The @code{rgbtestsrc} source generates an RGB test pattern useful for
14770 detecting RGB vs BGR issues. You should see a red, green and blue
14771 stripe from top to bottom.
14773 The @code{smptebars} source generates a color bars pattern, based on
14774 the SMPTE Engineering Guideline EG 1-1990.
14776 The @code{smptehdbars} source generates a color bars pattern, based on
14777 the SMPTE RP 219-2002.
14779 The @code{testsrc} source generates a test video pattern, showing a
14780 color pattern, a scrolling gradient and a timestamp. This is mainly
14781 intended for testing purposes.
14783 The @code{testsrc2} source is similar to testsrc, but supports more
14784 pixel formats instead of just @code{rgb24}. This allows using it as an
14785 input for other tests without requiring a format conversion.
14787 The sources accept the following parameters:
14792 Specify the color of the source, only available in the @code{color}
14793 source. For the syntax of this option, check the "Color" section in the
14794 ffmpeg-utils manual.
14797 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
14798 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
14799 pixels to be used as identity matrix for 3D lookup tables. Each component is
14800 coded on a @code{1/(N*N)} scale.
14803 Specify the size of the sourced video. For the syntax of this option, check the
14804 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14805 The default value is @code{320x240}.
14807 This option is not available with the @code{haldclutsrc} filter.
14810 Specify the frame rate of the sourced video, as the number of frames
14811 generated per second. It has to be a string in the format
14812 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
14813 number or a valid video frame rate abbreviation. The default value is
14817 Set the sample aspect ratio of the sourced video.
14820 Set the duration of the sourced video. See
14821 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
14822 for the accepted syntax.
14824 If not specified, or the expressed duration is negative, the video is
14825 supposed to be generated forever.
14828 Set the number of decimals to show in the timestamp, only available in the
14829 @code{testsrc} source.
14831 The displayed timestamp value will correspond to the original
14832 timestamp value multiplied by the power of 10 of the specified
14833 value. Default value is 0.
14836 For example the following:
14838 testsrc=duration=5.3:size=qcif:rate=10
14841 will generate a video with a duration of 5.3 seconds, with size
14842 176x144 and a frame rate of 10 frames per second.
14844 The following graph description will generate a red source
14845 with an opacity of 0.2, with size "qcif" and a frame rate of 10
14848 color=c=red@@0.2:s=qcif:r=10
14851 If the input content is to be ignored, @code{nullsrc} can be used. The
14852 following command generates noise in the luminance plane by employing
14853 the @code{geq} filter:
14855 nullsrc=s=256x256, geq=random(1)*255:128:128
14858 @subsection Commands
14860 The @code{color} source supports the following commands:
14864 Set the color of the created image. Accepts the same syntax of the
14865 corresponding @option{color} option.
14868 @c man end VIDEO SOURCES
14870 @chapter Video Sinks
14871 @c man begin VIDEO SINKS
14873 Below is a description of the currently available video sinks.
14875 @section buffersink
14877 Buffer video frames, and make them available to the end of the filter
14880 This sink is mainly intended for programmatic use, in particular
14881 through the interface defined in @file{libavfilter/buffersink.h}
14882 or the options system.
14884 It accepts a pointer to an AVBufferSinkContext structure, which
14885 defines the incoming buffers' formats, to be passed as the opaque
14886 parameter to @code{avfilter_init_filter} for initialization.
14890 Null video sink: do absolutely nothing with the input video. It is
14891 mainly useful as a template and for use in analysis / debugging
14894 @c man end VIDEO SINKS
14896 @chapter Multimedia Filters
14897 @c man begin MULTIMEDIA FILTERS
14899 Below is a description of the currently available multimedia filters.
14901 @section ahistogram
14903 Convert input audio to a video output, displaying the volume histogram.
14905 The filter accepts the following options:
14909 Specify how histogram is calculated.
14911 It accepts the following values:
14914 Use single histogram for all channels.
14916 Use separate histogram for each channel.
14918 Default is @code{single}.
14921 Set frame rate, expressed as number of frames per second. Default
14925 Specify the video size for the output. For the syntax of this option, check the
14926 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14927 Default value is @code{hd720}.
14932 It accepts the following values:
14943 reverse logarithmic
14945 Default is @code{log}.
14948 Set amplitude scale.
14950 It accepts the following values:
14957 Default is @code{log}.
14960 Set how much frames to accumulate in histogram.
14961 Defauls is 1. Setting this to -1 accumulates all frames.
14964 Set histogram ratio of window height.
14967 Set sonogram sliding.
14969 It accepts the following values:
14972 replace old rows with new ones.
14974 scroll from top to bottom.
14976 Default is @code{replace}.
14979 @section aphasemeter
14981 Convert input audio to a video output, displaying the audio phase.
14983 The filter accepts the following options:
14987 Set the output frame rate. Default value is @code{25}.
14990 Set the video size for the output. For the syntax of this option, check the
14991 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14992 Default value is @code{800x400}.
14997 Specify the red, green, blue contrast. Default values are @code{2},
14998 @code{7} and @code{1}.
14999 Allowed range is @code{[0, 255]}.
15002 Set color which will be used for drawing median phase. If color is
15003 @code{none} which is default, no median phase value will be drawn.
15006 The filter also exports the frame metadata @code{lavfi.aphasemeter.phase} which
15007 represents mean phase of current audio frame. Value is in range @code{[-1, 1]}.
15008 The @code{-1} means left and right channels are completely out of phase and
15009 @code{1} means channels are in phase.
15011 @section avectorscope
15013 Convert input audio to a video output, representing the audio vector
15016 The filter is used to measure the difference between channels of stereo
15017 audio stream. A monoaural signal, consisting of identical left and right
15018 signal, results in straight vertical line. Any stereo separation is visible
15019 as a deviation from this line, creating a Lissajous figure.
15020 If the straight (or deviation from it) but horizontal line appears this
15021 indicates that the left and right channels are out of phase.
15023 The filter accepts the following options:
15027 Set the vectorscope mode.
15029 Available values are:
15032 Lissajous rotated by 45 degrees.
15035 Same as above but not rotated.
15038 Shape resembling half of circle.
15041 Default value is @samp{lissajous}.
15044 Set the video size for the output. For the syntax of this option, check the
15045 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15046 Default value is @code{400x400}.
15049 Set the output frame rate. Default value is @code{25}.
15055 Specify the red, green, blue and alpha contrast. Default values are @code{40},
15056 @code{160}, @code{80} and @code{255}.
15057 Allowed range is @code{[0, 255]}.
15063 Specify the red, green, blue and alpha fade. Default values are @code{15},
15064 @code{10}, @code{5} and @code{5}.
15065 Allowed range is @code{[0, 255]}.
15068 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
15071 Set the vectorscope drawing mode.
15073 Available values are:
15076 Draw dot for each sample.
15079 Draw line between previous and current sample.
15082 Default value is @samp{dot}.
15085 @subsection Examples
15089 Complete example using @command{ffplay}:
15091 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
15092 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
15096 @section bench, abench
15098 Benchmark part of a filtergraph.
15100 The filter accepts the following options:
15104 Start or stop a timer.
15106 Available values are:
15109 Get the current time, set it as frame metadata (using the key
15110 @code{lavfi.bench.start_time}), and forward the frame to the next filter.
15113 Get the current time and fetch the @code{lavfi.bench.start_time} metadata from
15114 the input frame metadata to get the time difference. Time difference, average,
15115 maximum and minimum time (respectively @code{t}, @code{avg}, @code{max} and
15116 @code{min}) are then printed. The timestamps are expressed in seconds.
15120 @subsection Examples
15124 Benchmark @ref{selectivecolor} filter:
15126 bench=start,selectivecolor=reds=-.2 .12 -.49,bench=stop
15132 Concatenate audio and video streams, joining them together one after the
15135 The filter works on segments of synchronized video and audio streams. All
15136 segments must have the same number of streams of each type, and that will
15137 also be the number of streams at output.
15139 The filter accepts the following options:
15144 Set the number of segments. Default is 2.
15147 Set the number of output video streams, that is also the number of video
15148 streams in each segment. Default is 1.
15151 Set the number of output audio streams, that is also the number of audio
15152 streams in each segment. Default is 0.
15155 Activate unsafe mode: do not fail if segments have a different format.
15159 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
15160 @var{a} audio outputs.
15162 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
15163 segment, in the same order as the outputs, then the inputs for the second
15166 Related streams do not always have exactly the same duration, for various
15167 reasons including codec frame size or sloppy authoring. For that reason,
15168 related synchronized streams (e.g. a video and its audio track) should be
15169 concatenated at once. The concat filter will use the duration of the longest
15170 stream in each segment (except the last one), and if necessary pad shorter
15171 audio streams with silence.
15173 For this filter to work correctly, all segments must start at timestamp 0.
15175 All corresponding streams must have the same parameters in all segments; the
15176 filtering system will automatically select a common pixel format for video
15177 streams, and a common sample format, sample rate and channel layout for
15178 audio streams, but other settings, such as resolution, must be converted
15179 explicitly by the user.
15181 Different frame rates are acceptable but will result in variable frame rate
15182 at output; be sure to configure the output file to handle it.
15184 @subsection Examples
15188 Concatenate an opening, an episode and an ending, all in bilingual version
15189 (video in stream 0, audio in streams 1 and 2):
15191 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
15192 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
15193 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
15194 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
15198 Concatenate two parts, handling audio and video separately, using the
15199 (a)movie sources, and adjusting the resolution:
15201 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
15202 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
15203 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
15205 Note that a desync will happen at the stitch if the audio and video streams
15206 do not have exactly the same duration in the first file.
15213 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
15214 it unchanged. By default, it logs a message at a frequency of 10Hz with the
15215 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
15216 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
15218 The filter also has a video output (see the @var{video} option) with a real
15219 time graph to observe the loudness evolution. The graphic contains the logged
15220 message mentioned above, so it is not printed anymore when this option is set,
15221 unless the verbose logging is set. The main graphing area contains the
15222 short-term loudness (3 seconds of analysis), and the gauge on the right is for
15223 the momentary loudness (400 milliseconds).
15225 More information about the Loudness Recommendation EBU R128 on
15226 @url{http://tech.ebu.ch/loudness}.
15228 The filter accepts the following options:
15233 Activate the video output. The audio stream is passed unchanged whether this
15234 option is set or no. The video stream will be the first output stream if
15235 activated. Default is @code{0}.
15238 Set the video size. This option is for video only. For the syntax of this
15240 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15241 Default and minimum resolution is @code{640x480}.
15244 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
15245 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
15246 other integer value between this range is allowed.
15249 Set metadata injection. If set to @code{1}, the audio input will be segmented
15250 into 100ms output frames, each of them containing various loudness information
15251 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
15253 Default is @code{0}.
15256 Force the frame logging level.
15258 Available values are:
15261 information logging level
15263 verbose logging level
15266 By default, the logging level is set to @var{info}. If the @option{video} or
15267 the @option{metadata} options are set, it switches to @var{verbose}.
15272 Available modes can be cumulated (the option is a @code{flag} type). Possible
15276 Disable any peak mode (default).
15278 Enable sample-peak mode.
15280 Simple peak mode looking for the higher sample value. It logs a message
15281 for sample-peak (identified by @code{SPK}).
15283 Enable true-peak mode.
15285 If enabled, the peak lookup is done on an over-sampled version of the input
15286 stream for better peak accuracy. It logs a message for true-peak.
15287 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
15288 This mode requires a build with @code{libswresample}.
15292 Treat mono input files as "dual mono". If a mono file is intended for playback
15293 on a stereo system, its EBU R128 measurement will be perceptually incorrect.
15294 If set to @code{true}, this option will compensate for this effect.
15295 Multi-channel input files are not affected by this option.
15298 Set a specific pan law to be used for the measurement of dual mono files.
15299 This parameter is optional, and has a default value of -3.01dB.
15302 @subsection Examples
15306 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
15308 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
15312 Run an analysis with @command{ffmpeg}:
15314 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
15318 @section interleave, ainterleave
15320 Temporally interleave frames from several inputs.
15322 @code{interleave} works with video inputs, @code{ainterleave} with audio.
15324 These filters read frames from several inputs and send the oldest
15325 queued frame to the output.
15327 Input streams must have a well defined, monotonically increasing frame
15330 In order to submit one frame to output, these filters need to enqueue
15331 at least one frame for each input, so they cannot work in case one
15332 input is not yet terminated and will not receive incoming frames.
15334 For example consider the case when one input is a @code{select} filter
15335 which always drop input frames. The @code{interleave} filter will keep
15336 reading from that input, but it will never be able to send new frames
15337 to output until the input will send an end-of-stream signal.
15339 Also, depending on inputs synchronization, the filters will drop
15340 frames in case one input receives more frames than the other ones, and
15341 the queue is already filled.
15343 These filters accept the following options:
15347 Set the number of different inputs, it is 2 by default.
15350 @subsection Examples
15354 Interleave frames belonging to different streams using @command{ffmpeg}:
15356 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
15360 Add flickering blur effect:
15362 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
15366 @section perms, aperms
15368 Set read/write permissions for the output frames.
15370 These filters are mainly aimed at developers to test direct path in the
15371 following filter in the filtergraph.
15373 The filters accept the following options:
15377 Select the permissions mode.
15379 It accepts the following values:
15382 Do nothing. This is the default.
15384 Set all the output frames read-only.
15386 Set all the output frames directly writable.
15388 Make the frame read-only if writable, and writable if read-only.
15390 Set each output frame read-only or writable randomly.
15394 Set the seed for the @var{random} mode, must be an integer included between
15395 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
15396 @code{-1}, the filter will try to use a good random seed on a best effort
15400 Note: in case of auto-inserted filter between the permission filter and the
15401 following one, the permission might not be received as expected in that
15402 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
15403 perms/aperms filter can avoid this problem.
15405 @section realtime, arealtime
15407 Slow down filtering to match real time approximatively.
15409 These filters will pause the filtering for a variable amount of time to
15410 match the output rate with the input timestamps.
15411 They are similar to the @option{re} option to @code{ffmpeg}.
15413 They accept the following options:
15417 Time limit for the pauses. Any pause longer than that will be considered
15418 a timestamp discontinuity and reset the timer. Default is 2 seconds.
15421 @section select, aselect
15423 Select frames to pass in output.
15425 This filter accepts the following options:
15430 Set expression, which is evaluated for each input frame.
15432 If the expression is evaluated to zero, the frame is discarded.
15434 If the evaluation result is negative or NaN, the frame is sent to the
15435 first output; otherwise it is sent to the output with index
15436 @code{ceil(val)-1}, assuming that the input index starts from 0.
15438 For example a value of @code{1.2} corresponds to the output with index
15439 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
15442 Set the number of outputs. The output to which to send the selected
15443 frame is based on the result of the evaluation. Default value is 1.
15446 The expression can contain the following constants:
15450 The (sequential) number of the filtered frame, starting from 0.
15453 The (sequential) number of the selected frame, starting from 0.
15455 @item prev_selected_n
15456 The sequential number of the last selected frame. It's NAN if undefined.
15459 The timebase of the input timestamps.
15462 The PTS (Presentation TimeStamp) of the filtered video frame,
15463 expressed in @var{TB} units. It's NAN if undefined.
15466 The PTS of the filtered video frame,
15467 expressed in seconds. It's NAN if undefined.
15470 The PTS of the previously filtered video frame. It's NAN if undefined.
15472 @item prev_selected_pts
15473 The PTS of the last previously filtered video frame. It's NAN if undefined.
15475 @item prev_selected_t
15476 The PTS of the last previously selected video frame. It's NAN if undefined.
15479 The PTS of the first video frame in the video. It's NAN if undefined.
15482 The time of the first video frame in the video. It's NAN if undefined.
15484 @item pict_type @emph{(video only)}
15485 The type of the filtered frame. It can assume one of the following
15497 @item interlace_type @emph{(video only)}
15498 The frame interlace type. It can assume one of the following values:
15501 The frame is progressive (not interlaced).
15503 The frame is top-field-first.
15505 The frame is bottom-field-first.
15508 @item consumed_sample_n @emph{(audio only)}
15509 the number of selected samples before the current frame
15511 @item samples_n @emph{(audio only)}
15512 the number of samples in the current frame
15514 @item sample_rate @emph{(audio only)}
15515 the input sample rate
15518 This is 1 if the filtered frame is a key-frame, 0 otherwise.
15521 the position in the file of the filtered frame, -1 if the information
15522 is not available (e.g. for synthetic video)
15524 @item scene @emph{(video only)}
15525 value between 0 and 1 to indicate a new scene; a low value reflects a low
15526 probability for the current frame to introduce a new scene, while a higher
15527 value means the current frame is more likely to be one (see the example below)
15529 @item concatdec_select
15530 The concat demuxer can select only part of a concat input file by setting an
15531 inpoint and an outpoint, but the output packets may not be entirely contained
15532 in the selected interval. By using this variable, it is possible to skip frames
15533 generated by the concat demuxer which are not exactly contained in the selected
15536 This works by comparing the frame pts against the @var{lavf.concat.start_time}
15537 and the @var{lavf.concat.duration} packet metadata values which are also
15538 present in the decoded frames.
15540 The @var{concatdec_select} variable is -1 if the frame pts is at least
15541 start_time and either the duration metadata is missing or the frame pts is less
15542 than start_time + duration, 0 otherwise, and NaN if the start_time metadata is
15545 That basically means that an input frame is selected if its pts is within the
15546 interval set by the concat demuxer.
15550 The default value of the select expression is "1".
15552 @subsection Examples
15556 Select all frames in input:
15561 The example above is the same as:
15573 Select only I-frames:
15575 select='eq(pict_type\,I)'
15579 Select one frame every 100:
15581 select='not(mod(n\,100))'
15585 Select only frames contained in the 10-20 time interval:
15587 select=between(t\,10\,20)
15591 Select only I-frames contained in the 10-20 time interval:
15593 select=between(t\,10\,20)*eq(pict_type\,I)
15597 Select frames with a minimum distance of 10 seconds:
15599 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
15603 Use aselect to select only audio frames with samples number > 100:
15605 aselect='gt(samples_n\,100)'
15609 Create a mosaic of the first scenes:
15611 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
15614 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
15618 Send even and odd frames to separate outputs, and compose them:
15620 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
15624 Select useful frames from an ffconcat file which is using inpoints and
15625 outpoints but where the source files are not intra frame only.
15627 ffmpeg -copyts -vsync 0 -segment_time_metadata 1 -i input.ffconcat -vf select=concatdec_select -af aselect=concatdec_select output.avi
15631 @section sendcmd, asendcmd
15633 Send commands to filters in the filtergraph.
15635 These filters read commands to be sent to other filters in the
15638 @code{sendcmd} must be inserted between two video filters,
15639 @code{asendcmd} must be inserted between two audio filters, but apart
15640 from that they act the same way.
15642 The specification of commands can be provided in the filter arguments
15643 with the @var{commands} option, or in a file specified by the
15644 @var{filename} option.
15646 These filters accept the following options:
15649 Set the commands to be read and sent to the other filters.
15651 Set the filename of the commands to be read and sent to the other
15655 @subsection Commands syntax
15657 A commands description consists of a sequence of interval
15658 specifications, comprising a list of commands to be executed when a
15659 particular event related to that interval occurs. The occurring event
15660 is typically the current frame time entering or leaving a given time
15663 An interval is specified by the following syntax:
15665 @var{START}[-@var{END}] @var{COMMANDS};
15668 The time interval is specified by the @var{START} and @var{END} times.
15669 @var{END} is optional and defaults to the maximum time.
15671 The current frame time is considered within the specified interval if
15672 it is included in the interval [@var{START}, @var{END}), that is when
15673 the time is greater or equal to @var{START} and is lesser than
15676 @var{COMMANDS} consists of a sequence of one or more command
15677 specifications, separated by ",", relating to that interval. The
15678 syntax of a command specification is given by:
15680 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
15683 @var{FLAGS} is optional and specifies the type of events relating to
15684 the time interval which enable sending the specified command, and must
15685 be a non-null sequence of identifier flags separated by "+" or "|" and
15686 enclosed between "[" and "]".
15688 The following flags are recognized:
15691 The command is sent when the current frame timestamp enters the
15692 specified interval. In other words, the command is sent when the
15693 previous frame timestamp was not in the given interval, and the
15697 The command is sent when the current frame timestamp leaves the
15698 specified interval. In other words, the command is sent when the
15699 previous frame timestamp was in the given interval, and the
15703 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
15706 @var{TARGET} specifies the target of the command, usually the name of
15707 the filter class or a specific filter instance name.
15709 @var{COMMAND} specifies the name of the command for the target filter.
15711 @var{ARG} is optional and specifies the optional list of argument for
15712 the given @var{COMMAND}.
15714 Between one interval specification and another, whitespaces, or
15715 sequences of characters starting with @code{#} until the end of line,
15716 are ignored and can be used to annotate comments.
15718 A simplified BNF description of the commands specification syntax
15721 @var{COMMAND_FLAG} ::= "enter" | "leave"
15722 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
15723 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
15724 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
15725 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
15726 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
15729 @subsection Examples
15733 Specify audio tempo change at second 4:
15735 asendcmd=c='4.0 atempo tempo 1.5',atempo
15739 Specify a list of drawtext and hue commands in a file.
15741 # show text in the interval 5-10
15742 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
15743 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
15745 # desaturate the image in the interval 15-20
15746 15.0-20.0 [enter] hue s 0,
15747 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
15749 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
15751 # apply an exponential saturation fade-out effect, starting from time 25
15752 25 [enter] hue s exp(25-t)
15755 A filtergraph allowing to read and process the above command list
15756 stored in a file @file{test.cmd}, can be specified with:
15758 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
15763 @section setpts, asetpts
15765 Change the PTS (presentation timestamp) of the input frames.
15767 @code{setpts} works on video frames, @code{asetpts} on audio frames.
15769 This filter accepts the following options:
15774 The expression which is evaluated for each frame to construct its timestamp.
15778 The expression is evaluated through the eval API and can contain the following
15783 frame rate, only defined for constant frame-rate video
15786 The presentation timestamp in input
15789 The count of the input frame for video or the number of consumed samples,
15790 not including the current frame for audio, starting from 0.
15792 @item NB_CONSUMED_SAMPLES
15793 The number of consumed samples, not including the current frame (only
15796 @item NB_SAMPLES, S
15797 The number of samples in the current frame (only audio)
15799 @item SAMPLE_RATE, SR
15800 The audio sample rate.
15803 The PTS of the first frame.
15806 the time in seconds of the first frame
15809 State whether the current frame is interlaced.
15812 the time in seconds of the current frame
15815 original position in the file of the frame, or undefined if undefined
15816 for the current frame
15819 The previous input PTS.
15822 previous input time in seconds
15825 The previous output PTS.
15828 previous output time in seconds
15831 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
15835 The wallclock (RTC) time at the start of the movie in microseconds.
15838 The timebase of the input timestamps.
15842 @subsection Examples
15846 Start counting PTS from zero
15848 setpts=PTS-STARTPTS
15852 Apply fast motion effect:
15858 Apply slow motion effect:
15864 Set fixed rate of 25 frames per second:
15870 Set fixed rate 25 fps with some jitter:
15872 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
15876 Apply an offset of 10 seconds to the input PTS:
15882 Generate timestamps from a "live source" and rebase onto the current timebase:
15884 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
15888 Generate timestamps by counting samples:
15895 @section settb, asettb
15897 Set the timebase to use for the output frames timestamps.
15898 It is mainly useful for testing timebase configuration.
15900 It accepts the following parameters:
15905 The expression which is evaluated into the output timebase.
15909 The value for @option{tb} is an arithmetic expression representing a
15910 rational. The expression can contain the constants "AVTB" (the default
15911 timebase), "intb" (the input timebase) and "sr" (the sample rate,
15912 audio only). Default value is "intb".
15914 @subsection Examples
15918 Set the timebase to 1/25:
15924 Set the timebase to 1/10:
15930 Set the timebase to 1001/1000:
15936 Set the timebase to 2*intb:
15942 Set the default timebase value:
15949 Convert input audio to a video output representing frequency spectrum
15950 logarithmically using Brown-Puckette constant Q transform algorithm with
15951 direct frequency domain coefficient calculation (but the transform itself
15952 is not really constant Q, instead the Q factor is actually variable/clamped),
15953 with musical tone scale, from E0 to D#10.
15955 The filter accepts the following options:
15959 Specify the video size for the output. It must be even. For the syntax of this option,
15960 check the @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15961 Default value is @code{1920x1080}.
15964 Set the output frame rate. Default value is @code{25}.
15967 Set the bargraph height. It must be even. Default value is @code{-1} which
15968 computes the bargraph height automatically.
15971 Set the axis height. It must be even. Default value is @code{-1} which computes
15972 the axis height automatically.
15975 Set the sonogram height. It must be even. Default value is @code{-1} which
15976 computes the sonogram height automatically.
15979 Set the fullhd resolution. This option is deprecated, use @var{size}, @var{s}
15980 instead. Default value is @code{1}.
15982 @item sono_v, volume
15983 Specify the sonogram volume expression. It can contain variables:
15986 the @var{bar_v} evaluated expression
15987 @item frequency, freq, f
15988 the frequency where it is evaluated
15989 @item timeclamp, tc
15990 the value of @var{timeclamp} option
15994 @item a_weighting(f)
15995 A-weighting of equal loudness
15996 @item b_weighting(f)
15997 B-weighting of equal loudness
15998 @item c_weighting(f)
15999 C-weighting of equal loudness.
16001 Default value is @code{16}.
16003 @item bar_v, volume2
16004 Specify the bargraph volume expression. It can contain variables:
16007 the @var{sono_v} evaluated expression
16008 @item frequency, freq, f
16009 the frequency where it is evaluated
16010 @item timeclamp, tc
16011 the value of @var{timeclamp} option
16015 @item a_weighting(f)
16016 A-weighting of equal loudness
16017 @item b_weighting(f)
16018 B-weighting of equal loudness
16019 @item c_weighting(f)
16020 C-weighting of equal loudness.
16022 Default value is @code{sono_v}.
16024 @item sono_g, gamma
16025 Specify the sonogram gamma. Lower gamma makes the spectrum more contrast,
16026 higher gamma makes the spectrum having more range. Default value is @code{3}.
16027 Acceptable range is @code{[1, 7]}.
16029 @item bar_g, gamma2
16030 Specify the bargraph gamma. Default value is @code{1}. Acceptable range is
16033 @item timeclamp, tc
16034 Specify the transform timeclamp. At low frequency, there is trade-off between
16035 accuracy in time domain and frequency domain. If timeclamp is lower,
16036 event in time domain is represented more accurately (such as fast bass drum),
16037 otherwise event in frequency domain is represented more accurately
16038 (such as bass guitar). Acceptable range is @code{[0.1, 1]}. Default value is @code{0.17}.
16041 Specify the transform base frequency. Default value is @code{20.01523126408007475},
16042 which is frequency 50 cents below E0. Acceptable range is @code{[10, 100000]}.
16045 Specify the transform end frequency. Default value is @code{20495.59681441799654},
16046 which is frequency 50 cents above D#10. Acceptable range is @code{[10, 100000]}.
16049 This option is deprecated and ignored.
16052 Specify the transform length in time domain. Use this option to control accuracy
16053 trade-off between time domain and frequency domain at every frequency sample.
16054 It can contain variables:
16056 @item frequency, freq, f
16057 the frequency where it is evaluated
16058 @item timeclamp, tc
16059 the value of @var{timeclamp} option.
16061 Default value is @code{384*tc/(384+tc*f)}.
16064 Specify the transform count for every video frame. Default value is @code{6}.
16065 Acceptable range is @code{[1, 30]}.
16068 Specify the transform count for every single pixel. Default value is @code{0},
16069 which makes it computed automatically. Acceptable range is @code{[0, 10]}.
16072 Specify font file for use with freetype to draw the axis. If not specified,
16073 use embedded font. Note that drawing with font file or embedded font is not
16074 implemented with custom @var{basefreq} and @var{endfreq}, use @var{axisfile}
16078 Specify font color expression. This is arithmetic expression that should return
16079 integer value 0xRRGGBB. It can contain variables:
16081 @item frequency, freq, f
16082 the frequency where it is evaluated
16083 @item timeclamp, tc
16084 the value of @var{timeclamp} option
16089 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
16090 @item r(x), g(x), b(x)
16091 red, green, and blue value of intensity x.
16093 Default value is @code{st(0, (midi(f)-59.5)/12);
16094 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
16095 r(1-ld(1)) + b(ld(1))}.
16098 Specify image file to draw the axis. This option override @var{fontfile} and
16099 @var{fontcolor} option.
16102 Enable/disable drawing text to the axis. If it is set to @code{0}, drawing to
16103 the axis is disabled, ignoring @var{fontfile} and @var{axisfile} option.
16104 Default value is @code{1}.
16108 @subsection Examples
16112 Playing audio while showing the spectrum:
16114 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
16118 Same as above, but with frame rate 30 fps:
16120 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
16124 Playing at 1280x720:
16126 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=s=1280x720:count=4 [out0]'
16130 Disable sonogram display:
16136 A1 and its harmonics: A1, A2, (near)E3, A3:
16138 ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
16139 asplit[a][out1]; [a] showcqt [out0]'
16143 Same as above, but with more accuracy in frequency domain:
16145 ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
16146 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
16152 bar_v=10:sono_v=bar_v*a_weighting(f)
16156 Custom gamma, now spectrum is linear to the amplitude.
16162 Custom tlength equation:
16164 tc=0.33:tlength='st(0,0.17); 384*tc / (384 / ld(0) + tc*f /(1-ld(0))) + 384*tc / (tc*f / ld(0) + 384 /(1-ld(0)))'
16168 Custom fontcolor and fontfile, C-note is colored green, others are colored blue:
16170 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))':fontfile=myfont.ttf
16174 Custom frequency range with custom axis using image file:
16176 axisfile=myaxis.png:basefreq=40:endfreq=10000
16182 Convert input audio to video output representing the audio power spectrum.
16183 Audio amplitude is on Y-axis while frequency is on X-axis.
16185 The filter accepts the following options:
16189 Specify size of video. For the syntax of this option, check the
16190 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16191 Default is @code{1024x512}.
16195 This set how each frequency bin will be represented.
16197 It accepts the following values:
16203 Default is @code{bar}.
16206 Set amplitude scale.
16208 It accepts the following values:
16222 Default is @code{log}.
16225 Set frequency scale.
16227 It accepts the following values:
16236 Reverse logarithmic scale.
16238 Default is @code{lin}.
16243 It accepts the following values:
16259 Default is @code{w2048}
16262 Set windowing function.
16264 It accepts the following values:
16282 Default is @code{hanning}.
16285 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
16286 which means optimal overlap for selected window function will be picked.
16289 Set time averaging. Setting this to 0 will display current maximal peaks.
16290 Default is @code{1}, which means time averaging is disabled.
16293 Specify list of colors separated by space or by '|' which will be used to
16294 draw channel frequencies. Unrecognized or missing colors will be replaced
16298 Set channel display mode.
16300 It accepts the following values:
16305 Default is @code{combined}.
16309 @anchor{showspectrum}
16310 @section showspectrum
16312 Convert input audio to a video output, representing the audio frequency
16315 The filter accepts the following options:
16319 Specify the video size for the output. For the syntax of this option, check the
16320 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16321 Default value is @code{640x512}.
16324 Specify how the spectrum should slide along the window.
16326 It accepts the following values:
16329 the samples start again on the left when they reach the right
16331 the samples scroll from right to left
16333 the samples scroll from left to right
16335 frames are only produced when the samples reach the right
16338 Default value is @code{replace}.
16341 Specify display mode.
16343 It accepts the following values:
16346 all channels are displayed in the same row
16348 all channels are displayed in separate rows
16351 Default value is @samp{combined}.
16354 Specify display color mode.
16356 It accepts the following values:
16359 each channel is displayed in a separate color
16361 each channel is displayed using the same color scheme
16363 each channel is displayed using the rainbow color scheme
16365 each channel is displayed using the moreland color scheme
16367 each channel is displayed using the nebulae color scheme
16369 each channel is displayed using the fire color scheme
16371 each channel is displayed using the fiery color scheme
16373 each channel is displayed using the fruit color scheme
16375 each channel is displayed using the cool color scheme
16378 Default value is @samp{channel}.
16381 Specify scale used for calculating intensity color values.
16383 It accepts the following values:
16388 square root, default
16399 Default value is @samp{sqrt}.
16402 Set saturation modifier for displayed colors. Negative values provide
16403 alternative color scheme. @code{0} is no saturation at all.
16404 Saturation must be in [-10.0, 10.0] range.
16405 Default value is @code{1}.
16408 Set window function.
16410 It accepts the following values:
16430 Default value is @code{hann}.
16433 Set orientation of time vs frequency axis. Can be @code{vertical} or
16434 @code{horizontal}. Default is @code{vertical}.
16437 Set ratio of overlap window. Default value is @code{0}.
16438 When value is @code{1} overlap is set to recommended size for specific
16439 window function currently used.
16442 Set scale gain for calculating intensity color values.
16443 Default value is @code{1}.
16446 Set which data to display. Can be @code{magnitude}, default or @code{phase}.
16449 The usage is very similar to the showwaves filter; see the examples in that
16452 @subsection Examples
16456 Large window with logarithmic color scaling:
16458 showspectrum=s=1280x480:scale=log
16462 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
16464 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
16465 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
16469 @section showspectrumpic
16471 Convert input audio to a single video frame, representing the audio frequency
16474 The filter accepts the following options:
16478 Specify the video size for the output. For the syntax of this option, check the
16479 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16480 Default value is @code{4096x2048}.
16483 Specify display mode.
16485 It accepts the following values:
16488 all channels are displayed in the same row
16490 all channels are displayed in separate rows
16492 Default value is @samp{combined}.
16495 Specify display color mode.
16497 It accepts the following values:
16500 each channel is displayed in a separate color
16502 each channel is displayed using the same color scheme
16504 each channel is displayed using the rainbow color scheme
16506 each channel is displayed using the moreland color scheme
16508 each channel is displayed using the nebulae color scheme
16510 each channel is displayed using the fire color scheme
16512 each channel is displayed using the fiery color scheme
16514 each channel is displayed using the fruit color scheme
16516 each channel is displayed using the cool color scheme
16518 Default value is @samp{intensity}.
16521 Specify scale used for calculating intensity color values.
16523 It accepts the following values:
16528 square root, default
16538 Default value is @samp{log}.
16541 Set saturation modifier for displayed colors. Negative values provide
16542 alternative color scheme. @code{0} is no saturation at all.
16543 Saturation must be in [-10.0, 10.0] range.
16544 Default value is @code{1}.
16547 Set window function.
16549 It accepts the following values:
16568 Default value is @code{hann}.
16571 Set orientation of time vs frequency axis. Can be @code{vertical} or
16572 @code{horizontal}. Default is @code{vertical}.
16575 Set scale gain for calculating intensity color values.
16576 Default value is @code{1}.
16579 Draw time and frequency axes and legends. Default is enabled.
16582 @subsection Examples
16586 Extract an audio spectrogram of a whole audio track
16587 in a 1024x1024 picture using @command{ffmpeg}:
16589 ffmpeg -i audio.flac -lavfi showspectrumpic=s=1024x1024 spectrogram.png
16593 @section showvolume
16595 Convert input audio volume to a video output.
16597 The filter accepts the following options:
16604 Set border width, allowed range is [0, 5]. Default is 1.
16607 Set channel width, allowed range is [80, 8192]. Default is 400.
16610 Set channel height, allowed range is [1, 900]. Default is 20.
16613 Set fade, allowed range is [0.001, 1]. Default is 0.95.
16616 Set volume color expression.
16618 The expression can use the following variables:
16622 Current max volume of channel in dB.
16625 Current channel number, starting from 0.
16629 If set, displays channel names. Default is enabled.
16632 If set, displays volume values. Default is enabled.
16635 Set orientation, can be @code{horizontal} or @code{vertical},
16636 default is @code{horizontal}.
16639 Set step size, allowed range s [0, 5]. Default is 0, which means
16645 Convert input audio to a video output, representing the samples waves.
16647 The filter accepts the following options:
16651 Specify the video size for the output. For the syntax of this option, check the
16652 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16653 Default value is @code{600x240}.
16658 Available values are:
16661 Draw a point for each sample.
16664 Draw a vertical line for each sample.
16667 Draw a point for each sample and a line between them.
16670 Draw a centered vertical line for each sample.
16673 Default value is @code{point}.
16676 Set the number of samples which are printed on the same column. A
16677 larger value will decrease the frame rate. Must be a positive
16678 integer. This option can be set only if the value for @var{rate}
16679 is not explicitly specified.
16682 Set the (approximate) output frame rate. This is done by setting the
16683 option @var{n}. Default value is "25".
16685 @item split_channels
16686 Set if channels should be drawn separately or overlap. Default value is 0.
16689 Set colors separated by '|' which are going to be used for drawing of each channel.
16692 Set amplitude scale. Can be linear @code{lin} or logarithmic @code{log}.
16697 @subsection Examples
16701 Output the input file audio and the corresponding video representation
16704 amovie=a.mp3,asplit[out0],showwaves[out1]
16708 Create a synthetic signal and show it with showwaves, forcing a
16709 frame rate of 30 frames per second:
16711 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
16715 @section showwavespic
16717 Convert input audio to a single video frame, representing the samples waves.
16719 The filter accepts the following options:
16723 Specify the video size for the output. For the syntax of this option, check the
16724 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16725 Default value is @code{600x240}.
16727 @item split_channels
16728 Set if channels should be drawn separately or overlap. Default value is 0.
16731 Set colors separated by '|' which are going to be used for drawing of each channel.
16734 Set amplitude scale. Can be linear @code{lin} or logarithmic @code{log}.
16738 @subsection Examples
16742 Extract a channel split representation of the wave form of a whole audio track
16743 in a 1024x800 picture using @command{ffmpeg}:
16745 ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png
16749 @section spectrumsynth
16751 Sythesize audio from 2 input video spectrums, first input stream represents
16752 magnitude across time and second represents phase across time.
16753 The filter will transform from frequency domain as displayed in videos back
16754 to time domain as presented in audio output.
16756 This filter is primarly created for reversing processed @ref{showspectrum}
16757 filter outputs, but can synthesize sound from other spectrograms too.
16758 But in such case results are going to be poor if the phase data is not
16759 available, because in such cases phase data need to be recreated, usually
16760 its just recreated from random noise.
16761 For best results use gray only output (@code{channel} color mode in
16762 @ref{showspectrum} filter) and @code{log} scale for magnitude video and
16763 @code{lin} scale for phase video. To produce phase, for 2nd video, use
16764 @code{data} option. Inputs videos should generally use @code{fullframe}
16765 slide mode as that saves resources needed for decoding video.
16767 The filter accepts the following options:
16771 Specify sample rate of output audio, the sample rate of audio from which
16772 spectrum was generated may differ.
16775 Set number of channels represented in input video spectrums.
16778 Set scale which was used when generating magnitude input spectrum.
16779 Can be @code{lin} or @code{log}. Default is @code{log}.
16782 Set slide which was used when generating inputs spectrums.
16783 Can be @code{replace}, @code{scroll}, @code{fullframe} or @code{rscroll}.
16784 Default is @code{fullframe}.
16787 Set window function used for resynthesis.
16790 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
16791 which means optimal overlap for selected window function will be picked.
16794 Set orientation of input videos. Can be @code{vertical} or @code{horizontal}.
16795 Default is @code{vertical}.
16798 @subsection Examples
16802 First create magnitude and phase videos from audio, assuming audio is stereo with 44100 sample rate,
16803 then resynthesize videos back to audio with spectrumsynth:
16805 ffmpeg -i input.flac -lavfi showspectrum=mode=separate:scale=log:overlap=0.875:color=channel:slide=fullframe:data=magnitude -an -c:v rawvideo magnitude.nut
16806 ffmpeg -i input.flac -lavfi showspectrum=mode=separate:scale=lin:overlap=0.875:color=channel:slide=fullframe:data=phase -an -c:v rawvideo phase.nut
16807 ffmpeg -i magnitude.nut -i phase.nut -lavfi spectrumsynth=channels=2:sample_rate=44100:win_func=hann:overlap=0.875:slide=fullframe output.flac
16811 @section split, asplit
16813 Split input into several identical outputs.
16815 @code{asplit} works with audio input, @code{split} with video.
16817 The filter accepts a single parameter which specifies the number of outputs. If
16818 unspecified, it defaults to 2.
16820 @subsection Examples
16824 Create two separate outputs from the same input:
16826 [in] split [out0][out1]
16830 To create 3 or more outputs, you need to specify the number of
16833 [in] asplit=3 [out0][out1][out2]
16837 Create two separate outputs from the same input, one cropped and
16840 [in] split [splitout1][splitout2];
16841 [splitout1] crop=100:100:0:0 [cropout];
16842 [splitout2] pad=200:200:100:100 [padout];
16846 Create 5 copies of the input audio with @command{ffmpeg}:
16848 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
16854 Receive commands sent through a libzmq client, and forward them to
16855 filters in the filtergraph.
16857 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
16858 must be inserted between two video filters, @code{azmq} between two
16861 To enable these filters you need to install the libzmq library and
16862 headers and configure FFmpeg with @code{--enable-libzmq}.
16864 For more information about libzmq see:
16865 @url{http://www.zeromq.org/}
16867 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
16868 receives messages sent through a network interface defined by the
16869 @option{bind_address} option.
16871 The received message must be in the form:
16873 @var{TARGET} @var{COMMAND} [@var{ARG}]
16876 @var{TARGET} specifies the target of the command, usually the name of
16877 the filter class or a specific filter instance name.
16879 @var{COMMAND} specifies the name of the command for the target filter.
16881 @var{ARG} is optional and specifies the optional argument list for the
16882 given @var{COMMAND}.
16884 Upon reception, the message is processed and the corresponding command
16885 is injected into the filtergraph. Depending on the result, the filter
16886 will send a reply to the client, adopting the format:
16888 @var{ERROR_CODE} @var{ERROR_REASON}
16892 @var{MESSAGE} is optional.
16894 @subsection Examples
16896 Look at @file{tools/zmqsend} for an example of a zmq client which can
16897 be used to send commands processed by these filters.
16899 Consider the following filtergraph generated by @command{ffplay}
16901 ffplay -dumpgraph 1 -f lavfi "
16902 color=s=100x100:c=red [l];
16903 color=s=100x100:c=blue [r];
16904 nullsrc=s=200x100, zmq [bg];
16905 [bg][l] overlay [bg+l];
16906 [bg+l][r] overlay=x=100 "
16909 To change the color of the left side of the video, the following
16910 command can be used:
16912 echo Parsed_color_0 c yellow | tools/zmqsend
16915 To change the right side:
16917 echo Parsed_color_1 c pink | tools/zmqsend
16920 @c man end MULTIMEDIA FILTERS
16922 @chapter Multimedia Sources
16923 @c man begin MULTIMEDIA SOURCES
16925 Below is a description of the currently available multimedia sources.
16929 This is the same as @ref{movie} source, except it selects an audio
16935 Read audio and/or video stream(s) from a movie container.
16937 It accepts the following parameters:
16941 The name of the resource to read (not necessarily a file; it can also be a
16942 device or a stream accessed through some protocol).
16944 @item format_name, f
16945 Specifies the format assumed for the movie to read, and can be either
16946 the name of a container or an input device. If not specified, the
16947 format is guessed from @var{movie_name} or by probing.
16949 @item seek_point, sp
16950 Specifies the seek point in seconds. The frames will be output
16951 starting from this seek point. The parameter is evaluated with
16952 @code{av_strtod}, so the numerical value may be suffixed by an IS
16953 postfix. The default value is "0".
16956 Specifies the streams to read. Several streams can be specified,
16957 separated by "+". The source will then have as many outputs, in the
16958 same order. The syntax is explained in the ``Stream specifiers''
16959 section in the ffmpeg manual. Two special names, "dv" and "da" specify
16960 respectively the default (best suited) video and audio stream. Default
16961 is "dv", or "da" if the filter is called as "amovie".
16963 @item stream_index, si
16964 Specifies the index of the video stream to read. If the value is -1,
16965 the most suitable video stream will be automatically selected. The default
16966 value is "-1". Deprecated. If the filter is called "amovie", it will select
16967 audio instead of video.
16970 Specifies how many times to read the stream in sequence.
16971 If the value is less than 1, the stream will be read again and again.
16972 Default value is "1".
16974 Note that when the movie is looped the source timestamps are not
16975 changed, so it will generate non monotonically increasing timestamps.
16977 @item discontinuity
16978 Specifies the time difference between frames above which the point is
16979 considered a timestamp discontinuity which is removed by adjusting the later
16983 It allows overlaying a second video on top of the main input of
16984 a filtergraph, as shown in this graph:
16986 input -----------> deltapts0 --> overlay --> output
16989 movie --> scale--> deltapts1 -------+
16991 @subsection Examples
16995 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
16996 on top of the input labelled "in":
16998 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
16999 [in] setpts=PTS-STARTPTS [main];
17000 [main][over] overlay=16:16 [out]
17004 Read from a video4linux2 device, and overlay it on top of the input
17007 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
17008 [in] setpts=PTS-STARTPTS [main];
17009 [main][over] overlay=16:16 [out]
17013 Read the first video stream and the audio stream with id 0x81 from
17014 dvd.vob; the video is connected to the pad named "video" and the audio is
17015 connected to the pad named "audio":
17017 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
17021 @subsection Commands
17023 Both movie and amovie support the following commands:
17026 Perform seek using "av_seek_frame".
17027 The syntax is: seek @var{stream_index}|@var{timestamp}|@var{flags}
17030 @var{stream_index}: If stream_index is -1, a default
17031 stream is selected, and @var{timestamp} is automatically converted
17032 from AV_TIME_BASE units to the stream specific time_base.
17034 @var{timestamp}: Timestamp in AVStream.time_base units
17035 or, if no stream is specified, in AV_TIME_BASE units.
17037 @var{flags}: Flags which select direction and seeking mode.
17041 Get movie duration in AV_TIME_BASE units.
17045 @c man end MULTIMEDIA SOURCES