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.
2370 Apply a flanging effect to the audio.
2372 The filter accepts the following options:
2376 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
2379 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
2382 Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
2386 Set percentage of delayed signal mixed with original. Range from 0 to 100.
2387 Default value is 71.
2390 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
2393 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
2394 Default value is @var{sinusoidal}.
2397 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
2398 Default value is 25.
2401 Set delay-line interpolation, @var{linear} or @var{quadratic}.
2402 Default is @var{linear}.
2407 Apply a high-pass filter with 3dB point frequency.
2408 The filter can be either single-pole, or double-pole (the default).
2409 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2411 The filter accepts the following options:
2415 Set frequency in Hz. Default is 3000.
2418 Set number of poles. Default is 2.
2421 Set method to specify band-width of filter.
2434 Specify the band-width of a filter in width_type units.
2435 Applies only to double-pole filter.
2436 The default is 0.707q and gives a Butterworth response.
2441 Join multiple input streams into one multi-channel stream.
2443 It accepts the following parameters:
2447 The number of input streams. It defaults to 2.
2449 @item channel_layout
2450 The desired output channel layout. It defaults to stereo.
2453 Map channels from inputs to output. The argument is a '|'-separated list of
2454 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
2455 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
2456 can be either the name of the input channel (e.g. FL for front left) or its
2457 index in the specified input stream. @var{out_channel} is the name of the output
2461 The filter will attempt to guess the mappings when they are not specified
2462 explicitly. It does so by first trying to find an unused matching input channel
2463 and if that fails it picks the first unused input channel.
2465 Join 3 inputs (with properly set channel layouts):
2467 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
2470 Build a 5.1 output from 6 single-channel streams:
2472 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
2473 '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'
2479 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
2481 To enable compilation of this filter you need to configure FFmpeg with
2482 @code{--enable-ladspa}.
2486 Specifies the name of LADSPA plugin library to load. If the environment
2487 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
2488 each one of the directories specified by the colon separated list in
2489 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
2490 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
2491 @file{/usr/lib/ladspa/}.
2494 Specifies the plugin within the library. Some libraries contain only
2495 one plugin, but others contain many of them. If this is not set filter
2496 will list all available plugins within the specified library.
2499 Set the '|' separated list of controls which are zero or more floating point
2500 values that determine the behavior of the loaded plugin (for example delay,
2502 Controls need to be defined using the following syntax:
2503 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
2504 @var{valuei} is the value set on the @var{i}-th control.
2505 Alternatively they can be also defined using the following syntax:
2506 @var{value0}|@var{value1}|@var{value2}|..., where
2507 @var{valuei} is the value set on the @var{i}-th control.
2508 If @option{controls} is set to @code{help}, all available controls and
2509 their valid ranges are printed.
2511 @item sample_rate, s
2512 Specify the sample rate, default to 44100. Only used if plugin have
2516 Set the number of samples per channel per each output frame, default
2517 is 1024. Only used if plugin have zero inputs.
2520 Set the minimum duration of the sourced audio. See
2521 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2522 for the accepted syntax.
2523 Note that the resulting duration may be greater than the specified duration,
2524 as the generated audio is always cut at the end of a complete frame.
2525 If not specified, or the expressed duration is negative, the audio is
2526 supposed to be generated forever.
2527 Only used if plugin have zero inputs.
2531 @subsection Examples
2535 List all available plugins within amp (LADSPA example plugin) library:
2541 List all available controls and their valid ranges for @code{vcf_notch}
2542 plugin from @code{VCF} library:
2544 ladspa=f=vcf:p=vcf_notch:c=help
2548 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
2551 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
2555 Add reverberation to the audio using TAP-plugins
2556 (Tom's Audio Processing plugins):
2558 ladspa=file=tap_reverb:tap_reverb
2562 Generate white noise, with 0.2 amplitude:
2564 ladspa=file=cmt:noise_source_white:c=c0=.2
2568 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
2569 @code{C* Audio Plugin Suite} (CAPS) library:
2571 ladspa=file=caps:Click:c=c1=20'
2575 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
2577 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
2581 Increase volume by 20dB using fast lookahead limiter from Steve Harris
2582 @code{SWH Plugins} collection:
2584 ladspa=fast_lookahead_limiter_1913:fastLookaheadLimiter:20|0|2
2588 Attenuate low frequencies using Multiband EQ from Steve Harris
2589 @code{SWH Plugins} collection:
2591 ladspa=mbeq_1197:mbeq:-24|-24|-24|0|0|0|0|0|0|0|0|0|0|0|0
2595 @subsection Commands
2597 This filter supports the following commands:
2600 Modify the @var{N}-th control value.
2602 If the specified value is not valid, it is ignored and prior one is kept.
2607 Apply a low-pass filter with 3dB point frequency.
2608 The filter can be either single-pole or double-pole (the default).
2609 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2611 The filter accepts the following options:
2615 Set frequency in Hz. Default is 500.
2618 Set number of poles. Default is 2.
2621 Set method to specify band-width of filter.
2634 Specify the band-width of a filter in width_type units.
2635 Applies only to double-pole filter.
2636 The default is 0.707q and gives a Butterworth response.
2642 Mix channels with specific gain levels. The filter accepts the output
2643 channel layout followed by a set of channels definitions.
2645 This filter is also designed to efficiently remap the channels of an audio
2648 The filter accepts parameters of the form:
2649 "@var{l}|@var{outdef}|@var{outdef}|..."
2653 output channel layout or number of channels
2656 output channel specification, of the form:
2657 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
2660 output channel to define, either a channel name (FL, FR, etc.) or a channel
2661 number (c0, c1, etc.)
2664 multiplicative coefficient for the channel, 1 leaving the volume unchanged
2667 input channel to use, see out_name for details; it is not possible to mix
2668 named and numbered input channels
2671 If the `=' in a channel specification is replaced by `<', then the gains for
2672 that specification will be renormalized so that the total is 1, thus
2673 avoiding clipping noise.
2675 @subsection Mixing examples
2677 For example, if you want to down-mix from stereo to mono, but with a bigger
2678 factor for the left channel:
2680 pan=1c|c0=0.9*c0+0.1*c1
2683 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
2684 7-channels surround:
2686 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
2689 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
2690 that should be preferred (see "-ac" option) unless you have very specific
2693 @subsection Remapping examples
2695 The channel remapping will be effective if, and only if:
2698 @item gain coefficients are zeroes or ones,
2699 @item only one input per channel output,
2702 If all these conditions are satisfied, the filter will notify the user ("Pure
2703 channel mapping detected"), and use an optimized and lossless method to do the
2706 For example, if you have a 5.1 source and want a stereo audio stream by
2707 dropping the extra channels:
2709 pan="stereo| c0=FL | c1=FR"
2712 Given the same source, you can also switch front left and front right channels
2713 and keep the input channel layout:
2715 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
2718 If the input is a stereo audio stream, you can mute the front left channel (and
2719 still keep the stereo channel layout) with:
2724 Still with a stereo audio stream input, you can copy the right channel in both
2725 front left and right:
2727 pan="stereo| c0=FR | c1=FR"
2732 ReplayGain scanner filter. This filter takes an audio stream as an input and
2733 outputs it unchanged.
2734 At end of filtering it displays @code{track_gain} and @code{track_peak}.
2738 Convert the audio sample format, sample rate and channel layout. It is
2739 not meant to be used directly.
2742 Apply time-stretching and pitch-shifting with librubberband.
2744 The filter accepts the following options:
2748 Set tempo scale factor.
2751 Set pitch scale factor.
2754 Set transients detector.
2755 Possible values are:
2764 Possible values are:
2773 Possible values are:
2780 Set processing window size.
2781 Possible values are:
2790 Possible values are:
2797 Enable formant preservation when shift pitching.
2798 Possible values are:
2806 Possible values are:
2815 Possible values are:
2822 @section sidechaincompress
2824 This filter acts like normal compressor but has the ability to compress
2825 detected signal using second input signal.
2826 It needs two input streams and returns one output stream.
2827 First input stream will be processed depending on second stream signal.
2828 The filtered signal then can be filtered with other filters in later stages of
2829 processing. See @ref{pan} and @ref{amerge} filter.
2831 The filter accepts the following options:
2835 Set input gain. Default is 1. Range is between 0.015625 and 64.
2838 If a signal of second stream raises above this level it will affect the gain
2839 reduction of first stream.
2840 By default is 0.125. Range is between 0.00097563 and 1.
2843 Set a ratio about which the signal is reduced. 1:2 means that if the level
2844 raised 4dB above the threshold, it will be only 2dB above after the reduction.
2845 Default is 2. Range is between 1 and 20.
2848 Amount of milliseconds the signal has to rise above the threshold before gain
2849 reduction starts. Default is 20. Range is between 0.01 and 2000.
2852 Amount of milliseconds the signal has to fall below the threshold before
2853 reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
2856 Set the amount by how much signal will be amplified after processing.
2857 Default is 2. Range is from 1 and 64.
2860 Curve the sharp knee around the threshold to enter gain reduction more softly.
2861 Default is 2.82843. Range is between 1 and 8.
2864 Choose if the @code{average} level between all channels of side-chain stream
2865 or the louder(@code{maximum}) channel of side-chain stream affects the
2866 reduction. Default is @code{average}.
2869 Should the exact signal be taken in case of @code{peak} or an RMS one in case
2870 of @code{rms}. Default is @code{rms} which is mainly smoother.
2873 Set sidechain gain. Default is 1. Range is between 0.015625 and 64.
2876 How much to use compressed signal in output. Default is 1.
2877 Range is between 0 and 1.
2880 @subsection Examples
2884 Full ffmpeg example taking 2 audio inputs, 1st input to be compressed
2885 depending on the signal of 2nd input and later compressed signal to be
2886 merged with 2nd input:
2888 ffmpeg -i main.flac -i sidechain.flac -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress[compr];[compr][mix]amerge"
2892 @section sidechaingate
2894 A sidechain gate acts like a normal (wideband) gate but has the ability to
2895 filter the detected signal before sending it to the gain reduction stage.
2896 Normally a gate uses the full range signal to detect a level above the
2898 For example: If you cut all lower frequencies from your sidechain signal
2899 the gate will decrease the volume of your track only if not enough highs
2900 appear. With this technique you are able to reduce the resonation of a
2901 natural drum or remove "rumbling" of muted strokes from a heavily distorted
2903 It needs two input streams and returns one output stream.
2904 First input stream will be processed depending on second stream signal.
2906 The filter accepts the following options:
2910 Set input level before filtering.
2911 Default is 1. Allowed range is from 0.015625 to 64.
2914 Set the level of gain reduction when the signal is below the threshold.
2915 Default is 0.06125. Allowed range is from 0 to 1.
2918 If a signal rises above this level the gain reduction is released.
2919 Default is 0.125. Allowed range is from 0 to 1.
2922 Set a ratio about which the signal is reduced.
2923 Default is 2. Allowed range is from 1 to 9000.
2926 Amount of milliseconds the signal has to rise above the threshold before gain
2928 Default is 20 milliseconds. Allowed range is from 0.01 to 9000.
2931 Amount of milliseconds the signal has to fall below the threshold before the
2932 reduction is increased again. Default is 250 milliseconds.
2933 Allowed range is from 0.01 to 9000.
2936 Set amount of amplification of signal after processing.
2937 Default is 1. Allowed range is from 1 to 64.
2940 Curve the sharp knee around the threshold to enter gain reduction more softly.
2941 Default is 2.828427125. Allowed range is from 1 to 8.
2944 Choose if exact signal should be taken for detection or an RMS like one.
2945 Default is rms. Can be peak or rms.
2948 Choose if the average level between all channels or the louder channel affects
2950 Default is average. Can be average or maximum.
2953 Set sidechain gain. Default is 1. Range is from 0.015625 to 64.
2956 @section silencedetect
2958 Detect silence in an audio stream.
2960 This filter logs a message when it detects that the input audio volume is less
2961 or equal to a noise tolerance value for a duration greater or equal to the
2962 minimum detected noise duration.
2964 The printed times and duration are expressed in seconds.
2966 The filter accepts the following options:
2970 Set silence duration until notification (default is 2 seconds).
2973 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
2974 specified value) or amplitude ratio. Default is -60dB, or 0.001.
2977 @subsection Examples
2981 Detect 5 seconds of silence with -50dB noise tolerance:
2983 silencedetect=n=-50dB:d=5
2987 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
2988 tolerance in @file{silence.mp3}:
2990 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
2994 @section silenceremove
2996 Remove silence from the beginning, middle or end of the audio.
2998 The filter accepts the following options:
3002 This value is used to indicate if audio should be trimmed at beginning of
3003 the audio. A value of zero indicates no silence should be trimmed from the
3004 beginning. When specifying a non-zero value, it trims audio up until it
3005 finds non-silence. Normally, when trimming silence from beginning of audio
3006 the @var{start_periods} will be @code{1} but it can be increased to higher
3007 values to trim all audio up to specific count of non-silence periods.
3008 Default value is @code{0}.
3010 @item start_duration
3011 Specify the amount of time that non-silence must be detected before it stops
3012 trimming audio. By increasing the duration, bursts of noises can be treated
3013 as silence and trimmed off. Default value is @code{0}.
3015 @item start_threshold
3016 This indicates what sample value should be treated as silence. For digital
3017 audio, a value of @code{0} may be fine but for audio recorded from analog,
3018 you may wish to increase the value to account for background noise.
3019 Can be specified in dB (in case "dB" is appended to the specified value)
3020 or amplitude ratio. Default value is @code{0}.
3023 Set the count for trimming silence from the end of audio.
3024 To remove silence from the middle of a file, specify a @var{stop_periods}
3025 that is negative. This value is then treated as a positive value and is
3026 used to indicate the effect should restart processing as specified by
3027 @var{start_periods}, making it suitable for removing periods of silence
3028 in the middle of the audio.
3029 Default value is @code{0}.
3032 Specify a duration of silence that must exist before audio is not copied any
3033 more. By specifying a higher duration, silence that is wanted can be left in
3035 Default value is @code{0}.
3037 @item stop_threshold
3038 This is the same as @option{start_threshold} but for trimming silence from
3040 Can be specified in dB (in case "dB" is appended to the specified value)
3041 or amplitude ratio. Default value is @code{0}.
3044 This indicate that @var{stop_duration} length of audio should be left intact
3045 at the beginning of each period of silence.
3046 For example, if you want to remove long pauses between words but do not want
3047 to remove the pauses completely. Default value is @code{0}.
3050 Set how is silence detected. Can be @code{rms} or @code{peak}. Second is faster
3051 and works better with digital silence which is exactly 0.
3052 Default value is @code{rms}.
3055 Set ratio used to calculate size of window for detecting silence.
3056 Default value is @code{0.02}. Allowed range is from @code{0} to @code{10}.
3059 @subsection Examples
3063 The following example shows how this filter can be used to start a recording
3064 that does not contain the delay at the start which usually occurs between
3065 pressing the record button and the start of the performance:
3067 silenceremove=1:5:0.02
3071 Trim all silence encountered from begining to end where there is more than 1
3072 second of silence in audio:
3074 silenceremove=0:0:0:-1:1:-90dB
3080 SOFAlizer uses head-related transfer functions (HRTFs) to create virtual
3081 loudspeakers around the user for binaural listening via headphones (audio
3082 formats up to 9 channels supported).
3083 The HRTFs are stored in SOFA files (see @url{http://www.sofacoustics.org/} for a database).
3084 SOFAlizer is developed at the Acoustics Research Institute (ARI) of the
3085 Austrian Academy of Sciences.
3087 To enable compilation of this filter you need to configure FFmpeg with
3088 @code{--enable-netcdf}.
3090 The filter accepts the following options:
3094 Set the SOFA file used for rendering.
3097 Set gain applied to audio. Value is in dB. Default is 0.
3100 Set rotation of virtual loudspeakers in deg. Default is 0.
3103 Set elevation of virtual speakers in deg. Default is 0.
3106 Set distance in meters between loudspeakers and the listener with near-field
3107 HRTFs. Default is 1.
3110 Set processing type. Can be @var{time} or @var{freq}. @var{time} is
3111 processing audio in time domain which is slow but gives high quality output.
3112 @var{freq} is processing audio in frequency domain which is fast but gives
3113 mediocre output. Default is @var{freq}.
3116 @section stereotools
3118 This filter has some handy utilities to manage stereo signals, for converting
3119 M/S stereo recordings to L/R signal while having control over the parameters
3120 or spreading the stereo image of master track.
3122 The filter accepts the following options:
3126 Set input level before filtering for both channels. Defaults is 1.
3127 Allowed range is from 0.015625 to 64.
3130 Set output level after filtering for both channels. Defaults is 1.
3131 Allowed range is from 0.015625 to 64.
3134 Set input balance between both channels. Default is 0.
3135 Allowed range is from -1 to 1.
3138 Set output balance between both channels. Default is 0.
3139 Allowed range is from -1 to 1.
3142 Enable softclipping. Results in analog distortion instead of harsh digital 0dB
3143 clipping. Disabled by default.
3146 Mute the left channel. Disabled by default.
3149 Mute the right channel. Disabled by default.
3152 Change the phase of the left channel. Disabled by default.
3155 Change the phase of the right channel. Disabled by default.
3158 Set stereo mode. Available values are:
3162 Left/Right to Left/Right, this is default.
3165 Left/Right to Mid/Side.
3168 Mid/Side to Left/Right.
3171 Left/Right to Left/Left.
3174 Left/Right to Right/Right.
3177 Left/Right to Left + Right.
3180 Left/Right to Right/Left.
3184 Set level of side signal. Default is 1.
3185 Allowed range is from 0.015625 to 64.
3188 Set balance of side signal. Default is 0.
3189 Allowed range is from -1 to 1.
3192 Set level of the middle signal. Default is 1.
3193 Allowed range is from 0.015625 to 64.
3196 Set middle signal pan. Default is 0. Allowed range is from -1 to 1.
3199 Set stereo base between mono and inversed channels. Default is 0.
3200 Allowed range is from -1 to 1.
3203 Set delay in milliseconds how much to delay left from right channel and
3204 vice versa. Default is 0. Allowed range is from -20 to 20.
3207 Set S/C level. Default is 1. Allowed range is from 1 to 100.
3210 Set the stereo phase in degrees. Default is 0. Allowed range is from 0 to 360.
3213 @section stereowiden
3215 This filter enhance the stereo effect by suppressing signal common to both
3216 channels and by delaying the signal of left into right and vice versa,
3217 thereby widening the stereo effect.
3219 The filter accepts the following options:
3223 Time in milliseconds of the delay of left signal into right and vice versa.
3224 Default is 20 milliseconds.
3227 Amount of gain in delayed signal into right and vice versa. Gives a delay
3228 effect of left signal in right output and vice versa which gives widening
3229 effect. Default is 0.3.
3232 Cross feed of left into right with inverted phase. This helps in suppressing
3233 the mono. If the value is 1 it will cancel all the signal common to both
3234 channels. Default is 0.3.
3237 Set level of input signal of original channel. Default is 0.8.
3242 Boost or cut treble (upper) frequencies of the audio using a two-pole
3243 shelving filter with a response similar to that of a standard
3244 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
3246 The filter accepts the following options:
3250 Give the gain at whichever is the lower of ~22 kHz and the
3251 Nyquist frequency. Its useful range is about -20 (for a large cut)
3252 to +20 (for a large boost). Beware of clipping when using a positive gain.
3255 Set the filter's central frequency and so can be used
3256 to extend or reduce the frequency range to be boosted or cut.
3257 The default value is @code{3000} Hz.
3260 Set method to specify band-width of filter.
3273 Determine how steep is the filter's shelf transition.
3278 Sinusoidal amplitude modulation.
3280 The filter accepts the following options:
3284 Modulation frequency in Hertz. Modulation frequencies in the subharmonic range
3285 (20 Hz or lower) will result in a tremolo effect.
3286 This filter may also be used as a ring modulator by specifying
3287 a modulation frequency higher than 20 Hz.
3288 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
3291 Depth of modulation as a percentage. Range is 0.0 - 1.0.
3292 Default value is 0.5.
3297 Sinusoidal phase modulation.
3299 The filter accepts the following options:
3303 Modulation frequency in Hertz.
3304 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
3307 Depth of modulation as a percentage. Range is 0.0 - 1.0.
3308 Default value is 0.5.
3313 Adjust the input audio volume.
3315 It accepts the following parameters:
3319 Set audio volume expression.
3321 Output values are clipped to the maximum value.
3323 The output audio volume is given by the relation:
3325 @var{output_volume} = @var{volume} * @var{input_volume}
3328 The default value for @var{volume} is "1.0".
3331 This parameter represents the mathematical precision.
3333 It determines which input sample formats will be allowed, which affects the
3334 precision of the volume scaling.
3338 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
3340 32-bit floating-point; this limits input sample format to FLT. (default)
3342 64-bit floating-point; this limits input sample format to DBL.
3346 Choose the behaviour on encountering ReplayGain side data in input frames.
3350 Remove ReplayGain side data, ignoring its contents (the default).
3353 Ignore ReplayGain side data, but leave it in the frame.
3356 Prefer the track gain, if present.
3359 Prefer the album gain, if present.
3362 @item replaygain_preamp
3363 Pre-amplification gain in dB to apply to the selected replaygain gain.
3365 Default value for @var{replaygain_preamp} is 0.0.
3368 Set when the volume expression is evaluated.
3370 It accepts the following values:
3373 only evaluate expression once during the filter initialization, or
3374 when the @samp{volume} command is sent
3377 evaluate expression for each incoming frame
3380 Default value is @samp{once}.
3383 The volume expression can contain the following parameters.
3387 frame number (starting at zero)
3390 @item nb_consumed_samples
3391 number of samples consumed by the filter
3393 number of samples in the current frame
3395 original frame position in the file
3401 PTS at start of stream
3403 time at start of stream
3409 last set volume value
3412 Note that when @option{eval} is set to @samp{once} only the
3413 @var{sample_rate} and @var{tb} variables are available, all other
3414 variables will evaluate to NAN.
3416 @subsection Commands
3418 This filter supports the following commands:
3421 Modify the volume expression.
3422 The command accepts the same syntax of the corresponding option.
3424 If the specified expression is not valid, it is kept at its current
3426 @item replaygain_noclip
3427 Prevent clipping by limiting the gain applied.
3429 Default value for @var{replaygain_noclip} is 1.
3433 @subsection Examples
3437 Halve the input audio volume:
3441 volume=volume=-6.0206dB
3444 In all the above example the named key for @option{volume} can be
3445 omitted, for example like in:
3451 Increase input audio power by 6 decibels using fixed-point precision:
3453 volume=volume=6dB:precision=fixed
3457 Fade volume after time 10 with an annihilation period of 5 seconds:
3459 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
3463 @section volumedetect
3465 Detect the volume of the input video.
3467 The filter has no parameters. The input is not modified. Statistics about
3468 the volume will be printed in the log when the input stream end is reached.
3470 In particular it will show the mean volume (root mean square), maximum
3471 volume (on a per-sample basis), and the beginning of a histogram of the
3472 registered volume values (from the maximum value to a cumulated 1/1000 of
3475 All volumes are in decibels relative to the maximum PCM value.
3477 @subsection Examples
3479 Here is an excerpt of the output:
3481 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
3482 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
3483 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
3484 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
3485 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
3486 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
3487 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
3488 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
3489 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
3495 The mean square energy is approximately -27 dB, or 10^-2.7.
3497 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
3499 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
3502 In other words, raising the volume by +4 dB does not cause any clipping,
3503 raising it by +5 dB causes clipping for 6 samples, etc.
3505 @c man end AUDIO FILTERS
3507 @chapter Audio Sources
3508 @c man begin AUDIO SOURCES
3510 Below is a description of the currently available audio sources.
3514 Buffer audio frames, and make them available to the filter chain.
3516 This source is mainly intended for a programmatic use, in particular
3517 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
3519 It accepts the following parameters:
3523 The timebase which will be used for timestamps of submitted frames. It must be
3524 either a floating-point number or in @var{numerator}/@var{denominator} form.
3527 The sample rate of the incoming audio buffers.
3530 The sample format of the incoming audio buffers.
3531 Either a sample format name or its corresponding integer representation from
3532 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
3534 @item channel_layout
3535 The channel layout of the incoming audio buffers.
3536 Either a channel layout name from channel_layout_map in
3537 @file{libavutil/channel_layout.c} or its corresponding integer representation
3538 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
3541 The number of channels of the incoming audio buffers.
3542 If both @var{channels} and @var{channel_layout} are specified, then they
3547 @subsection Examples
3550 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
3553 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
3554 Since the sample format with name "s16p" corresponds to the number
3555 6 and the "stereo" channel layout corresponds to the value 0x3, this is
3558 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
3563 Generate an audio signal specified by an expression.
3565 This source accepts in input one or more expressions (one for each
3566 channel), which are evaluated and used to generate a corresponding
3569 This source accepts the following options:
3573 Set the '|'-separated expressions list for each separate channel. In case the
3574 @option{channel_layout} option is not specified, the selected channel layout
3575 depends on the number of provided expressions. Otherwise the last
3576 specified expression is applied to the remaining output channels.
3578 @item channel_layout, c
3579 Set the channel layout. The number of channels in the specified layout
3580 must be equal to the number of specified expressions.
3583 Set the minimum duration of the sourced audio. See
3584 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
3585 for the accepted syntax.
3586 Note that the resulting duration may be greater than the specified
3587 duration, as the generated audio is always cut at the end of a
3590 If not specified, or the expressed duration is negative, the audio is
3591 supposed to be generated forever.
3594 Set the number of samples per channel per each output frame,
3597 @item sample_rate, s
3598 Specify the sample rate, default to 44100.
3601 Each expression in @var{exprs} can contain the following constants:
3605 number of the evaluated sample, starting from 0
3608 time of the evaluated sample expressed in seconds, starting from 0
3615 @subsection Examples
3625 Generate a sin signal with frequency of 440 Hz, set sample rate to
3628 aevalsrc="sin(440*2*PI*t):s=8000"
3632 Generate a two channels signal, specify the channel layout (Front
3633 Center + Back Center) explicitly:
3635 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
3639 Generate white noise:
3641 aevalsrc="-2+random(0)"
3645 Generate an amplitude modulated signal:
3647 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
3651 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
3653 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
3660 The null audio source, return unprocessed audio frames. It is mainly useful
3661 as a template and to be employed in analysis / debugging tools, or as
3662 the source for filters which ignore the input data (for example the sox
3665 This source accepts the following options:
3669 @item channel_layout, cl
3671 Specifies the channel layout, and can be either an integer or a string
3672 representing a channel layout. The default value of @var{channel_layout}
3675 Check the channel_layout_map definition in
3676 @file{libavutil/channel_layout.c} for the mapping between strings and
3677 channel layout values.
3679 @item sample_rate, r
3680 Specifies the sample rate, and defaults to 44100.
3683 Set the number of samples per requested frames.
3687 @subsection Examples
3691 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
3693 anullsrc=r=48000:cl=4
3697 Do the same operation with a more obvious syntax:
3699 anullsrc=r=48000:cl=mono
3703 All the parameters need to be explicitly defined.
3707 Synthesize a voice utterance using the libflite library.
3709 To enable compilation of this filter you need to configure FFmpeg with
3710 @code{--enable-libflite}.
3712 Note that the flite library is not thread-safe.
3714 The filter accepts the following options:
3719 If set to 1, list the names of the available voices and exit
3720 immediately. Default value is 0.
3723 Set the maximum number of samples per frame. Default value is 512.
3726 Set the filename containing the text to speak.
3729 Set the text to speak.
3732 Set the voice to use for the speech synthesis. Default value is
3733 @code{kal}. See also the @var{list_voices} option.
3736 @subsection Examples
3740 Read from file @file{speech.txt}, and synthesize the text using the
3741 standard flite voice:
3743 flite=textfile=speech.txt
3747 Read the specified text selecting the @code{slt} voice:
3749 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
3753 Input text to ffmpeg:
3755 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
3759 Make @file{ffplay} speak the specified text, using @code{flite} and
3760 the @code{lavfi} device:
3762 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
3766 For more information about libflite, check:
3767 @url{http://www.speech.cs.cmu.edu/flite/}
3771 Generate a noise audio signal.
3773 The filter accepts the following options:
3776 @item sample_rate, r
3777 Specify the sample rate. Default value is 48000 Hz.
3780 Specify the amplitude (0.0 - 1.0) of the generated audio stream. Default value
3784 Specify the duration of the generated audio stream. Not specifying this option
3785 results in noise with an infinite length.
3787 @item color, colour, c
3788 Specify the color of noise. Available noise colors are white, pink, and brown.
3789 Default color is white.
3792 Specify a value used to seed the PRNG.
3795 Set the number of samples per each output frame, default is 1024.
3798 @subsection Examples
3803 Generate 60 seconds of pink noise, with a 44.1 kHz sampling rate and an amplitude of 0.5:
3805 anoisesrc=d=60:c=pink:r=44100:a=0.5
3811 Generate an audio signal made of a sine wave with amplitude 1/8.
3813 The audio signal is bit-exact.
3815 The filter accepts the following options:
3820 Set the carrier frequency. Default is 440 Hz.
3822 @item beep_factor, b
3823 Enable a periodic beep every second with frequency @var{beep_factor} times
3824 the carrier frequency. Default is 0, meaning the beep is disabled.
3826 @item sample_rate, r
3827 Specify the sample rate, default is 44100.
3830 Specify the duration of the generated audio stream.
3832 @item samples_per_frame
3833 Set the number of samples per output frame.
3835 The expression can contain the following constants:
3839 The (sequential) number of the output audio frame, starting from 0.
3842 The PTS (Presentation TimeStamp) of the output audio frame,
3843 expressed in @var{TB} units.
3846 The PTS of the output audio frame, expressed in seconds.
3849 The timebase of the output audio frames.
3852 Default is @code{1024}.
3855 @subsection Examples
3860 Generate a simple 440 Hz sine wave:
3866 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
3870 sine=frequency=220:beep_factor=4:duration=5
3874 Generate a 1 kHz sine wave following @code{1602,1601,1602,1601,1602} NTSC
3877 sine=1000:samples_per_frame='st(0,mod(n,5)); 1602-not(not(eq(ld(0),1)+eq(ld(0),3)))'
3881 @c man end AUDIO SOURCES
3883 @chapter Audio Sinks
3884 @c man begin AUDIO SINKS
3886 Below is a description of the currently available audio sinks.
3888 @section abuffersink
3890 Buffer audio frames, and make them available to the end of filter chain.
3892 This sink is mainly intended for programmatic use, in particular
3893 through the interface defined in @file{libavfilter/buffersink.h}
3894 or the options system.
3896 It accepts a pointer to an AVABufferSinkContext structure, which
3897 defines the incoming buffers' formats, to be passed as the opaque
3898 parameter to @code{avfilter_init_filter} for initialization.
3901 Null audio sink; do absolutely nothing with the input audio. It is
3902 mainly useful as a template and for use in analysis / debugging
3905 @c man end AUDIO SINKS
3907 @chapter Video Filters
3908 @c man begin VIDEO FILTERS
3910 When you configure your FFmpeg build, you can disable any of the
3911 existing filters using @code{--disable-filters}.
3912 The configure output will show the video filters included in your
3915 Below is a description of the currently available video filters.
3917 @section alphaextract
3919 Extract the alpha component from the input as a grayscale video. This
3920 is especially useful with the @var{alphamerge} filter.
3924 Add or replace the alpha component of the primary input with the
3925 grayscale value of a second input. This is intended for use with
3926 @var{alphaextract} to allow the transmission or storage of frame
3927 sequences that have alpha in a format that doesn't support an alpha
3930 For example, to reconstruct full frames from a normal YUV-encoded video
3931 and a separate video created with @var{alphaextract}, you might use:
3933 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
3936 Since this filter is designed for reconstruction, it operates on frame
3937 sequences without considering timestamps, and terminates when either
3938 input reaches end of stream. This will cause problems if your encoding
3939 pipeline drops frames. If you're trying to apply an image as an
3940 overlay to a video stream, consider the @var{overlay} filter instead.
3944 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
3945 and libavformat to work. On the other hand, it is limited to ASS (Advanced
3946 Substation Alpha) subtitles files.
3948 This filter accepts the following option in addition to the common options from
3949 the @ref{subtitles} filter:
3953 Set the shaping engine
3955 Available values are:
3958 The default libass shaping engine, which is the best available.
3960 Fast, font-agnostic shaper that can do only substitutions
3962 Slower shaper using OpenType for substitutions and positioning
3965 The default is @code{auto}.
3969 Apply an Adaptive Temporal Averaging Denoiser to the video input.
3971 The filter accepts the following options:
3975 Set threshold A for 1st plane. Default is 0.02.
3976 Valid range is 0 to 0.3.
3979 Set threshold B for 1st plane. Default is 0.04.
3980 Valid range is 0 to 5.
3983 Set threshold A for 2nd plane. Default is 0.02.
3984 Valid range is 0 to 0.3.
3987 Set threshold B for 2nd plane. Default is 0.04.
3988 Valid range is 0 to 5.
3991 Set threshold A for 3rd plane. Default is 0.02.
3992 Valid range is 0 to 0.3.
3995 Set threshold B for 3rd plane. Default is 0.04.
3996 Valid range is 0 to 5.
3998 Threshold A is designed to react on abrupt changes in the input signal and
3999 threshold B is designed to react on continuous changes in the input signal.
4002 Set number of frames filter will use for averaging. Default is 33. Must be odd
4003 number in range [5, 129].
4008 Compute the bounding box for the non-black pixels in the input frame
4011 This filter computes the bounding box containing all the pixels with a
4012 luminance value greater than the minimum allowed value.
4013 The parameters describing the bounding box are printed on the filter
4016 The filter accepts the following option:
4020 Set the minimal luminance value. Default is @code{16}.
4023 @section blackdetect
4025 Detect video intervals that are (almost) completely black. Can be
4026 useful to detect chapter transitions, commercials, or invalid
4027 recordings. Output lines contains the time for the start, end and
4028 duration of the detected black interval expressed in seconds.
4030 In order to display the output lines, you need to set the loglevel at
4031 least to the AV_LOG_INFO value.
4033 The filter accepts the following options:
4036 @item black_min_duration, d
4037 Set the minimum detected black duration expressed in seconds. It must
4038 be a non-negative floating point number.
4040 Default value is 2.0.
4042 @item picture_black_ratio_th, pic_th
4043 Set the threshold for considering a picture "black".
4044 Express the minimum value for the ratio:
4046 @var{nb_black_pixels} / @var{nb_pixels}
4049 for which a picture is considered black.
4050 Default value is 0.98.
4052 @item pixel_black_th, pix_th
4053 Set the threshold for considering a pixel "black".
4055 The threshold expresses the maximum pixel luminance value for which a
4056 pixel is considered "black". The provided value is scaled according to
4057 the following equation:
4059 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
4062 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
4063 the input video format, the range is [0-255] for YUV full-range
4064 formats and [16-235] for YUV non full-range formats.
4066 Default value is 0.10.
4069 The following example sets the maximum pixel threshold to the minimum
4070 value, and detects only black intervals of 2 or more seconds:
4072 blackdetect=d=2:pix_th=0.00
4077 Detect frames that are (almost) completely black. Can be useful to
4078 detect chapter transitions or commercials. Output lines consist of
4079 the frame number of the detected frame, the percentage of blackness,
4080 the position in the file if known or -1 and the timestamp in seconds.
4082 In order to display the output lines, you need to set the loglevel at
4083 least to the AV_LOG_INFO value.
4085 It accepts the following parameters:
4090 The percentage of the pixels that have to be below the threshold; it defaults to
4093 @item threshold, thresh
4094 The threshold below which a pixel value is considered black; it defaults to
4099 @section blend, tblend
4101 Blend two video frames into each other.
4103 The @code{blend} filter takes two input streams and outputs one
4104 stream, the first input is the "top" layer and second input is
4105 "bottom" layer. Output terminates when shortest input terminates.
4107 The @code{tblend} (time blend) filter takes two consecutive frames
4108 from one single stream, and outputs the result obtained by blending
4109 the new frame on top of the old frame.
4111 A description of the accepted options follows.
4119 Set blend mode for specific pixel component or all pixel components in case
4120 of @var{all_mode}. Default value is @code{normal}.
4122 Available values for component modes are:
4161 Set blend opacity for specific pixel component or all pixel components in case
4162 of @var{all_opacity}. Only used in combination with pixel component blend modes.
4169 Set blend expression for specific pixel component or all pixel components in case
4170 of @var{all_expr}. Note that related mode options will be ignored if those are set.
4172 The expressions can use the following variables:
4176 The sequential number of the filtered frame, starting from @code{0}.
4180 the coordinates of the current sample
4184 the width and height of currently filtered plane
4188 Width and height scale depending on the currently filtered plane. It is the
4189 ratio between the corresponding luma plane number of pixels and the current
4190 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4191 @code{0.5,0.5} for chroma planes.
4194 Time of the current frame, expressed in seconds.
4197 Value of pixel component at current location for first video frame (top layer).
4200 Value of pixel component at current location for second video frame (bottom layer).
4204 Force termination when the shortest input terminates. Default is
4205 @code{0}. This option is only defined for the @code{blend} filter.
4208 Continue applying the last bottom frame after the end of the stream. A value of
4209 @code{0} disable the filter after the last frame of the bottom layer is reached.
4210 Default is @code{1}. This option is only defined for the @code{blend} filter.
4213 @subsection Examples
4217 Apply transition from bottom layer to top layer in first 10 seconds:
4219 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
4223 Apply 1x1 checkerboard effect:
4225 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
4229 Apply uncover left effect:
4231 blend=all_expr='if(gte(N*SW+X,W),A,B)'
4235 Apply uncover down effect:
4237 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
4241 Apply uncover up-left effect:
4243 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
4247 Split diagonally video and shows top and bottom layer on each side:
4249 blend=all_expr=if(gt(X,Y*(W/H)),A,B)
4253 Display differences between the current and the previous frame:
4255 tblend=all_mode=difference128
4261 Apply a boxblur algorithm to the input video.
4263 It accepts the following parameters:
4267 @item luma_radius, lr
4268 @item luma_power, lp
4269 @item chroma_radius, cr
4270 @item chroma_power, cp
4271 @item alpha_radius, ar
4272 @item alpha_power, ap
4276 A description of the accepted options follows.
4279 @item luma_radius, lr
4280 @item chroma_radius, cr
4281 @item alpha_radius, ar
4282 Set an expression for the box radius in pixels used for blurring the
4283 corresponding input plane.
4285 The radius value must be a non-negative number, and must not be
4286 greater than the value of the expression @code{min(w,h)/2} for the
4287 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
4290 Default value for @option{luma_radius} is "2". If not specified,
4291 @option{chroma_radius} and @option{alpha_radius} default to the
4292 corresponding value set for @option{luma_radius}.
4294 The expressions can contain the following constants:
4298 The input width and height in pixels.
4302 The input chroma image width and height in pixels.
4306 The horizontal and vertical chroma subsample values. For example, for the
4307 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
4310 @item luma_power, lp
4311 @item chroma_power, cp
4312 @item alpha_power, ap
4313 Specify how many times the boxblur filter is applied to the
4314 corresponding plane.
4316 Default value for @option{luma_power} is 2. If not specified,
4317 @option{chroma_power} and @option{alpha_power} default to the
4318 corresponding value set for @option{luma_power}.
4320 A value of 0 will disable the effect.
4323 @subsection Examples
4327 Apply a boxblur filter with the luma, chroma, and alpha radii
4330 boxblur=luma_radius=2:luma_power=1
4335 Set the luma radius to 2, and alpha and chroma radius to 0:
4337 boxblur=2:1:cr=0:ar=0
4341 Set the luma and chroma radii to a fraction of the video dimension:
4343 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
4348 YUV colorspace color/chroma keying.
4350 The filter accepts the following options:
4354 The color which will be replaced with transparency.
4357 Similarity percentage with the key color.
4359 0.01 matches only the exact key color, while 1.0 matches everything.
4364 0.0 makes pixels either fully transparent, or not transparent at all.
4366 Higher values result in semi-transparent pixels, with a higher transparency
4367 the more similar the pixels color is to the key color.
4370 Signals that the color passed is already in YUV instead of RGB.
4372 Litteral colors like "green" or "red" don't make sense with this enabled anymore.
4373 This can be used to pass exact YUV values as hexadecimal numbers.
4376 @subsection Examples
4380 Make every green pixel in the input image transparent:
4382 ffmpeg -i input.png -vf chromakey=green out.png
4386 Overlay a greenscreen-video on top of a static black background.
4388 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
4394 Visualize information exported by some codecs.
4396 Some codecs can export information through frames using side-data or other
4397 means. For example, some MPEG based codecs export motion vectors through the
4398 @var{export_mvs} flag in the codec @option{flags2} option.
4400 The filter accepts the following option:
4404 Set motion vectors to visualize.
4406 Available flags for @var{mv} are:
4410 forward predicted MVs of P-frames
4412 forward predicted MVs of B-frames
4414 backward predicted MVs of B-frames
4418 Display quantization parameters using the chroma planes
4421 @subsection Examples
4425 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
4427 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
4431 @section colorbalance
4432 Modify intensity of primary colors (red, green and blue) of input frames.
4434 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
4435 regions for the red-cyan, green-magenta or blue-yellow balance.
4437 A positive adjustment value shifts the balance towards the primary color, a negative
4438 value towards the complementary color.
4440 The filter accepts the following options:
4446 Adjust red, green and blue shadows (darkest pixels).
4451 Adjust red, green and blue midtones (medium pixels).
4456 Adjust red, green and blue highlights (brightest pixels).
4458 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
4461 @subsection Examples
4465 Add red color cast to shadows:
4472 RGB colorspace color keying.
4474 The filter accepts the following options:
4478 The color which will be replaced with transparency.
4481 Similarity percentage with the key color.
4483 0.01 matches only the exact key color, while 1.0 matches everything.
4488 0.0 makes pixels either fully transparent, or not transparent at all.
4490 Higher values result in semi-transparent pixels, with a higher transparency
4491 the more similar the pixels color is to the key color.
4494 @subsection Examples
4498 Make every green pixel in the input image transparent:
4500 ffmpeg -i input.png -vf colorkey=green out.png
4504 Overlay a greenscreen-video on top of a static background image.
4506 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
4510 @section colorlevels
4512 Adjust video input frames using levels.
4514 The filter accepts the following options:
4521 Adjust red, green, blue and alpha input black point.
4522 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
4528 Adjust red, green, blue and alpha input white point.
4529 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
4531 Input levels are used to lighten highlights (bright tones), darken shadows
4532 (dark tones), change the balance of bright and dark tones.
4538 Adjust red, green, blue and alpha output black point.
4539 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
4545 Adjust red, green, blue and alpha output white point.
4546 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
4548 Output levels allows manual selection of a constrained output level range.
4551 @subsection Examples
4555 Make video output darker:
4557 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
4563 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
4567 Make video output lighter:
4569 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
4573 Increase brightness:
4575 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
4579 @section colorchannelmixer
4581 Adjust video input frames by re-mixing color channels.
4583 This filter modifies a color channel by adding the values associated to
4584 the other channels of the same pixels. For example if the value to
4585 modify is red, the output value will be:
4587 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
4590 The filter accepts the following options:
4597 Adjust contribution of input red, green, blue and alpha channels for output red channel.
4598 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
4604 Adjust contribution of input red, green, blue and alpha channels for output green channel.
4605 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
4611 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
4612 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
4618 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
4619 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
4621 Allowed ranges for options are @code{[-2.0, 2.0]}.
4624 @subsection Examples
4628 Convert source to grayscale:
4630 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
4633 Simulate sepia tones:
4635 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
4639 @section colormatrix
4641 Convert color matrix.
4643 The filter accepts the following options:
4648 Specify the source and destination color matrix. Both values must be
4651 The accepted values are:
4667 For example to convert from BT.601 to SMPTE-240M, use the command:
4669 colormatrix=bt601:smpte240m
4672 @section convolution
4674 Apply convolution 3x3 or 5x5 filter.
4676 The filter accepts the following options:
4683 Set matrix for each plane.
4684 Matrix is sequence of 9 or 25 signed integers.
4690 Set multiplier for calculated value for each plane.
4696 Set bias for each plane. This value is added to the result of the multiplication.
4697 Useful for making the overall image brighter or darker. Default is 0.0.
4700 @subsection Examples
4706 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"
4712 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"
4718 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"
4724 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"
4730 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"
4736 Copy the input source unchanged to the output. This is mainly useful for
4741 Crop the input video to given dimensions.
4743 It accepts the following parameters:
4747 The width of the output video. It defaults to @code{iw}.
4748 This expression is evaluated only once during the filter
4749 configuration, or when the @samp{w} or @samp{out_w} command is sent.
4752 The height of the output video. It defaults to @code{ih}.
4753 This expression is evaluated only once during the filter
4754 configuration, or when the @samp{h} or @samp{out_h} command is sent.
4757 The horizontal position, in the input video, of the left edge of the output
4758 video. It defaults to @code{(in_w-out_w)/2}.
4759 This expression is evaluated per-frame.
4762 The vertical position, in the input video, of the top edge of the output video.
4763 It defaults to @code{(in_h-out_h)/2}.
4764 This expression is evaluated per-frame.
4767 If set to 1 will force the output display aspect ratio
4768 to be the same of the input, by changing the output sample aspect
4769 ratio. It defaults to 0.
4772 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
4773 expressions containing the following constants:
4778 The computed values for @var{x} and @var{y}. They are evaluated for
4783 The input width and height.
4787 These are the same as @var{in_w} and @var{in_h}.
4791 The output (cropped) width and height.
4795 These are the same as @var{out_w} and @var{out_h}.
4798 same as @var{iw} / @var{ih}
4801 input sample aspect ratio
4804 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
4808 horizontal and vertical chroma subsample values. For example for the
4809 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4812 The number of the input frame, starting from 0.
4815 the position in the file of the input frame, NAN if unknown
4818 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
4822 The expression for @var{out_w} may depend on the value of @var{out_h},
4823 and the expression for @var{out_h} may depend on @var{out_w}, but they
4824 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
4825 evaluated after @var{out_w} and @var{out_h}.
4827 The @var{x} and @var{y} parameters specify the expressions for the
4828 position of the top-left corner of the output (non-cropped) area. They
4829 are evaluated for each frame. If the evaluated value is not valid, it
4830 is approximated to the nearest valid value.
4832 The expression for @var{x} may depend on @var{y}, and the expression
4833 for @var{y} may depend on @var{x}.
4835 @subsection Examples
4839 Crop area with size 100x100 at position (12,34).
4844 Using named options, the example above becomes:
4846 crop=w=100:h=100:x=12:y=34
4850 Crop the central input area with size 100x100:
4856 Crop the central input area with size 2/3 of the input video:
4858 crop=2/3*in_w:2/3*in_h
4862 Crop the input video central square:
4869 Delimit the rectangle with the top-left corner placed at position
4870 100:100 and the right-bottom corner corresponding to the right-bottom
4871 corner of the input image.
4873 crop=in_w-100:in_h-100:100:100
4877 Crop 10 pixels from the left and right borders, and 20 pixels from
4878 the top and bottom borders
4880 crop=in_w-2*10:in_h-2*20
4884 Keep only the bottom right quarter of the input image:
4886 crop=in_w/2:in_h/2:in_w/2:in_h/2
4890 Crop height for getting Greek harmony:
4892 crop=in_w:1/PHI*in_w
4896 Apply trembling effect:
4898 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)
4902 Apply erratic camera effect depending on timestamp:
4904 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)"
4908 Set x depending on the value of y:
4910 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
4914 @subsection Commands
4916 This filter supports the following commands:
4922 Set width/height of the output video and the horizontal/vertical position
4924 The command accepts the same syntax of the corresponding option.
4926 If the specified expression is not valid, it is kept at its current
4932 Auto-detect the crop size.
4934 It calculates the necessary cropping parameters and prints the
4935 recommended parameters via the logging system. The detected dimensions
4936 correspond to the non-black area of the input video.
4938 It accepts the following parameters:
4943 Set higher black value threshold, which can be optionally specified
4944 from nothing (0) to everything (255 for 8bit based formats). An intensity
4945 value greater to the set value is considered non-black. It defaults to 24.
4946 You can also specify a value between 0.0 and 1.0 which will be scaled depending
4947 on the bitdepth of the pixel format.
4950 The value which the width/height should be divisible by. It defaults to
4951 16. The offset is automatically adjusted to center the video. Use 2 to
4952 get only even dimensions (needed for 4:2:2 video). 16 is best when
4953 encoding to most video codecs.
4955 @item reset_count, reset
4956 Set the counter that determines after how many frames cropdetect will
4957 reset the previously detected largest video area and start over to
4958 detect the current optimal crop area. Default value is 0.
4960 This can be useful when channel logos distort the video area. 0
4961 indicates 'never reset', and returns the largest area encountered during
4968 Apply color adjustments using curves.
4970 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
4971 component (red, green and blue) has its values defined by @var{N} key points
4972 tied from each other using a smooth curve. The x-axis represents the pixel
4973 values from the input frame, and the y-axis the new pixel values to be set for
4976 By default, a component curve is defined by the two points @var{(0;0)} and
4977 @var{(1;1)}. This creates a straight line where each original pixel value is
4978 "adjusted" to its own value, which means no change to the image.
4980 The filter allows you to redefine these two points and add some more. A new
4981 curve (using a natural cubic spline interpolation) will be define to pass
4982 smoothly through all these new coordinates. The new defined points needs to be
4983 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
4984 be in the @var{[0;1]} interval. If the computed curves happened to go outside
4985 the vector spaces, the values will be clipped accordingly.
4987 If there is no key point defined in @code{x=0}, the filter will automatically
4988 insert a @var{(0;0)} point. In the same way, if there is no key point defined
4989 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
4991 The filter accepts the following options:
4995 Select one of the available color presets. This option can be used in addition
4996 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
4997 options takes priority on the preset values.
4998 Available presets are:
5001 @item color_negative
5004 @item increase_contrast
5006 @item linear_contrast
5007 @item medium_contrast
5009 @item strong_contrast
5012 Default is @code{none}.
5014 Set the master key points. These points will define a second pass mapping. It
5015 is sometimes called a "luminance" or "value" mapping. It can be used with
5016 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
5017 post-processing LUT.
5019 Set the key points for the red component.
5021 Set the key points for the green component.
5023 Set the key points for the blue component.
5025 Set the key points for all components (not including master).
5026 Can be used in addition to the other key points component
5027 options. In this case, the unset component(s) will fallback on this
5028 @option{all} setting.
5030 Specify a Photoshop curves file (@code{.acv}) to import the settings from.
5033 To avoid some filtergraph syntax conflicts, each key points list need to be
5034 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
5036 @subsection Examples
5040 Increase slightly the middle level of blue:
5042 curves=blue='0.5/0.58'
5048 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
5050 Here we obtain the following coordinates for each components:
5053 @code{(0;0.11) (0.42;0.51) (1;0.95)}
5055 @code{(0;0) (0.50;0.48) (1;1)}
5057 @code{(0;0.22) (0.49;0.44) (1;0.80)}
5061 The previous example can also be achieved with the associated built-in preset:
5063 curves=preset=vintage
5073 Use a Photoshop preset and redefine the points of the green component:
5075 curves=psfile='MyCurvesPresets/purple.acv':green='0.45/0.53'
5081 Denoise frames using 2D DCT (frequency domain filtering).
5083 This filter is not designed for real time.
5085 The filter accepts the following options:
5089 Set the noise sigma constant.
5091 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
5092 coefficient (absolute value) below this threshold with be dropped.
5094 If you need a more advanced filtering, see @option{expr}.
5096 Default is @code{0}.
5099 Set number overlapping pixels for each block. Since the filter can be slow, you
5100 may want to reduce this value, at the cost of a less effective filter and the
5101 risk of various artefacts.
5103 If the overlapping value doesn't permit processing the whole input width or
5104 height, a warning will be displayed and according borders won't be denoised.
5106 Default value is @var{blocksize}-1, which is the best possible setting.
5109 Set the coefficient factor expression.
5111 For each coefficient of a DCT block, this expression will be evaluated as a
5112 multiplier value for the coefficient.
5114 If this is option is set, the @option{sigma} option will be ignored.
5116 The absolute value of the coefficient can be accessed through the @var{c}
5120 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
5121 @var{blocksize}, which is the width and height of the processed blocks.
5123 The default value is @var{3} (8x8) and can be raised to @var{4} for a
5124 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
5125 on the speed processing. Also, a larger block size does not necessarily means a
5129 @subsection Examples
5131 Apply a denoise with a @option{sigma} of @code{4.5}:
5136 The same operation can be achieved using the expression system:
5138 dctdnoiz=e='gte(c, 4.5*3)'
5141 Violent denoise using a block size of @code{16x16}:
5148 Remove banding artifacts from input video.
5149 It works by replacing banded pixels with average value of referenced pixels.
5151 The filter accepts the following options:
5158 Set banding detection threshold for each plane. Default is 0.02.
5159 Valid range is 0.00003 to 0.5.
5160 If difference between current pixel and reference pixel is less than threshold,
5161 it will be considered as banded.
5164 Banding detection range in pixels. Default is 16. If positive, random number
5165 in range 0 to set value will be used. If negative, exact absolute value
5167 The range defines square of four pixels around current pixel.
5170 Set direction in radians from which four pixel will be compared. If positive,
5171 random direction from 0 to set direction will be picked. If negative, exact of
5172 absolute value will be picked. For example direction 0, -PI or -2*PI radians
5173 will pick only pixels on same row and -PI/2 will pick only pixels on same
5177 If enabled, current pixel is compared with average value of all four
5178 surrounding pixels. The default is enabled. If disabled current pixel is
5179 compared with all four surrounding pixels. The pixel is considered banded
5180 if only all four differences with surrounding pixels are less than threshold.
5186 Drop duplicated frames at regular intervals.
5188 The filter accepts the following options:
5192 Set the number of frames from which one will be dropped. Setting this to
5193 @var{N} means one frame in every batch of @var{N} frames will be dropped.
5194 Default is @code{5}.
5197 Set the threshold for duplicate detection. If the difference metric for a frame
5198 is less than or equal to this value, then it is declared as duplicate. Default
5202 Set scene change threshold. Default is @code{15}.
5206 Set the size of the x and y-axis blocks used during metric calculations.
5207 Larger blocks give better noise suppression, but also give worse detection of
5208 small movements. Must be a power of two. Default is @code{32}.
5211 Mark main input as a pre-processed input and activate clean source input
5212 stream. This allows the input to be pre-processed with various filters to help
5213 the metrics calculation while keeping the frame selection lossless. When set to
5214 @code{1}, the first stream is for the pre-processed input, and the second
5215 stream is the clean source from where the kept frames are chosen. Default is
5219 Set whether or not chroma is considered in the metric calculations. Default is
5225 Apply deflate effect to the video.
5227 This filter replaces the pixel by the local(3x3) average by taking into account
5228 only values lower than the pixel.
5230 It accepts the following options:
5237 Limit the maximum change for each plane, default is 65535.
5238 If 0, plane will remain unchanged.
5243 Remove judder produced by partially interlaced telecined content.
5245 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
5246 source was partially telecined content then the output of @code{pullup,dejudder}
5247 will have a variable frame rate. May change the recorded frame rate of the
5248 container. Aside from that change, this filter will not affect constant frame
5251 The option available in this filter is:
5255 Specify the length of the window over which the judder repeats.
5257 Accepts any integer greater than 1. Useful values are:
5261 If the original was telecined from 24 to 30 fps (Film to NTSC).
5264 If the original was telecined from 25 to 30 fps (PAL to NTSC).
5267 If a mixture of the two.
5270 The default is @samp{4}.
5275 Suppress a TV station logo by a simple interpolation of the surrounding
5276 pixels. Just set a rectangle covering the logo and watch it disappear
5277 (and sometimes something even uglier appear - your mileage may vary).
5279 It accepts the following parameters:
5284 Specify the top left corner coordinates of the logo. They must be
5289 Specify the width and height of the logo to clear. They must be
5293 Specify the thickness of the fuzzy edge of the rectangle (added to
5294 @var{w} and @var{h}). The default value is 1. This option is
5295 deprecated, setting higher values should no longer be necessary and
5299 When set to 1, a green rectangle is drawn on the screen to simplify
5300 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
5301 The default value is 0.
5303 The rectangle is drawn on the outermost pixels which will be (partly)
5304 replaced with interpolated values. The values of the next pixels
5305 immediately outside this rectangle in each direction will be used to
5306 compute the interpolated pixel values inside the rectangle.
5310 @subsection Examples
5314 Set a rectangle covering the area with top left corner coordinates 0,0
5315 and size 100x77, and a band of size 10:
5317 delogo=x=0:y=0:w=100:h=77:band=10
5324 Attempt to fix small changes in horizontal and/or vertical shift. This
5325 filter helps remove camera shake from hand-holding a camera, bumping a
5326 tripod, moving on a vehicle, etc.
5328 The filter accepts the following options:
5336 Specify a rectangular area where to limit the search for motion
5338 If desired the search for motion vectors can be limited to a
5339 rectangular area of the frame defined by its top left corner, width
5340 and height. These parameters have the same meaning as the drawbox
5341 filter which can be used to visualise the position of the bounding
5344 This is useful when simultaneous movement of subjects within the frame
5345 might be confused for camera motion by the motion vector search.
5347 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
5348 then the full frame is used. This allows later options to be set
5349 without specifying the bounding box for the motion vector search.
5351 Default - search the whole frame.
5355 Specify the maximum extent of movement in x and y directions in the
5356 range 0-64 pixels. Default 16.
5359 Specify how to generate pixels to fill blanks at the edge of the
5360 frame. Available values are:
5363 Fill zeroes at blank locations
5365 Original image at blank locations
5367 Extruded edge value at blank locations
5369 Mirrored edge at blank locations
5371 Default value is @samp{mirror}.
5374 Specify the blocksize to use for motion search. Range 4-128 pixels,
5378 Specify the contrast threshold for blocks. Only blocks with more than
5379 the specified contrast (difference between darkest and lightest
5380 pixels) will be considered. Range 1-255, default 125.
5383 Specify the search strategy. Available values are:
5386 Set exhaustive search
5388 Set less exhaustive search.
5390 Default value is @samp{exhaustive}.
5393 If set then a detailed log of the motion search is written to the
5397 If set to 1, specify using OpenCL capabilities, only available if
5398 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
5404 Apply an exact inverse of the telecine operation. It requires a predefined
5405 pattern specified using the pattern option which must be the same as that passed
5406 to the telecine filter.
5408 This filter accepts the following options:
5417 The default value is @code{top}.
5421 A string of numbers representing the pulldown pattern you wish to apply.
5422 The default value is @code{23}.
5425 A number representing position of the first frame with respect to the telecine
5426 pattern. This is to be used if the stream is cut. The default value is @code{0}.
5431 Apply dilation effect to the video.
5433 This filter replaces the pixel by the local(3x3) maximum.
5435 It accepts the following options:
5442 Limit the maximum change for each plane, default is 65535.
5443 If 0, plane will remain unchanged.
5446 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
5449 Flags to local 3x3 coordinates maps like this:
5458 Displace pixels as indicated by second and third input stream.
5460 It takes three input streams and outputs one stream, the first input is the
5461 source, and second and third input are displacement maps.
5463 The second input specifies how much to displace pixels along the
5464 x-axis, while the third input specifies how much to displace pixels
5466 If one of displacement map streams terminates, last frame from that
5467 displacement map will be used.
5469 Note that once generated, displacements maps can be reused over and over again.
5471 A description of the accepted options follows.
5475 Set displace behavior for pixels that are out of range.
5477 Available values are:
5480 Missing pixels are replaced by black pixels.
5483 Adjacent pixels will spread out to replace missing pixels.
5486 Out of range pixels are wrapped so they point to pixels of other side.
5488 Default is @samp{smear}.
5492 @subsection Examples
5496 Add ripple effect to rgb input of video size hd720:
5498 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
5502 Add wave effect to rgb input of video size hd720:
5504 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
5510 Draw a colored box on the input image.
5512 It accepts the following parameters:
5517 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
5521 The expressions which specify the width and height of the box; if 0 they are interpreted as
5522 the input width and height. It defaults to 0.
5525 Specify the color of the box to write. For the general syntax of this option,
5526 check the "Color" section in the ffmpeg-utils manual. If the special
5527 value @code{invert} is used, the box edge color is the same as the
5528 video with inverted luma.
5531 The expression which sets the thickness of the box edge. Default value is @code{3}.
5533 See below for the list of accepted constants.
5536 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
5537 following constants:
5541 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
5545 horizontal and vertical chroma subsample values. For example for the
5546 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5550 The input width and height.
5553 The input sample aspect ratio.
5557 The x and y offset coordinates where the box is drawn.
5561 The width and height of the drawn box.
5564 The thickness of the drawn box.
5566 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
5567 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
5571 @subsection Examples
5575 Draw a black box around the edge of the input image:
5581 Draw a box with color red and an opacity of 50%:
5583 drawbox=10:20:200:60:red@@0.5
5586 The previous example can be specified as:
5588 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
5592 Fill the box with pink color:
5594 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
5598 Draw a 2-pixel red 2.40:1 mask:
5600 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
5604 @section drawgraph, adrawgraph
5606 Draw a graph using input video or audio metadata.
5608 It accepts the following parameters:
5612 Set 1st frame metadata key from which metadata values will be used to draw a graph.
5615 Set 1st foreground color expression.
5618 Set 2nd frame metadata key from which metadata values will be used to draw a graph.
5621 Set 2nd foreground color expression.
5624 Set 3rd frame metadata key from which metadata values will be used to draw a graph.
5627 Set 3rd foreground color expression.
5630 Set 4th frame metadata key from which metadata values will be used to draw a graph.
5633 Set 4th foreground color expression.
5636 Set minimal value of metadata value.
5639 Set maximal value of metadata value.
5642 Set graph background color. Default is white.
5647 Available values for mode is:
5654 Default is @code{line}.
5659 Available values for slide is:
5662 Draw new frame when right border is reached.
5665 Replace old columns with new ones.
5668 Scroll from right to left.
5671 Scroll from left to right.
5674 Default is @code{frame}.
5677 Set size of graph video. For the syntax of this option, check the
5678 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
5679 The default value is @code{900x256}.
5681 The foreground color expressions can use the following variables:
5684 Minimal value of metadata value.
5687 Maximal value of metadata value.
5690 Current metadata key value.
5693 The color is defined as 0xAABBGGRR.
5696 Example using metadata from @ref{signalstats} filter:
5698 signalstats,drawgraph=lavfi.signalstats.YAVG:min=0:max=255
5701 Example using metadata from @ref{ebur128} filter:
5703 ebur128=metadata=1,adrawgraph=lavfi.r128.M:min=-120:max=5
5708 Draw a grid on the input image.
5710 It accepts the following parameters:
5715 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
5719 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
5720 input width and height, respectively, minus @code{thickness}, so image gets
5721 framed. Default to 0.
5724 Specify the color of the grid. For the general syntax of this option,
5725 check the "Color" section in the ffmpeg-utils manual. If the special
5726 value @code{invert} is used, the grid color is the same as the
5727 video with inverted luma.
5730 The expression which sets the thickness of the grid line. Default value is @code{1}.
5732 See below for the list of accepted constants.
5735 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
5736 following constants:
5740 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
5744 horizontal and vertical chroma subsample values. For example for the
5745 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5749 The input grid cell width and height.
5752 The input sample aspect ratio.
5756 The x and y coordinates of some point of grid intersection (meant to configure offset).
5760 The width and height of the drawn cell.
5763 The thickness of the drawn cell.
5765 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
5766 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
5770 @subsection Examples
5774 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
5776 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
5780 Draw a white 3x3 grid with an opacity of 50%:
5782 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
5789 Draw a text string or text from a specified file on top of a video, using the
5790 libfreetype library.
5792 To enable compilation of this filter, you need to configure FFmpeg with
5793 @code{--enable-libfreetype}.
5794 To enable default font fallback and the @var{font} option you need to
5795 configure FFmpeg with @code{--enable-libfontconfig}.
5796 To enable the @var{text_shaping} option, you need to configure FFmpeg with
5797 @code{--enable-libfribidi}.
5801 It accepts the following parameters:
5806 Used to draw a box around text using the background color.
5807 The value must be either 1 (enable) or 0 (disable).
5808 The default value of @var{box} is 0.
5811 Set the width of the border to be drawn around the box using @var{boxcolor}.
5812 The default value of @var{boxborderw} is 0.
5815 The color to be used for drawing box around text. For the syntax of this
5816 option, check the "Color" section in the ffmpeg-utils manual.
5818 The default value of @var{boxcolor} is "white".
5821 Set the width of the border to be drawn around the text using @var{bordercolor}.
5822 The default value of @var{borderw} is 0.
5825 Set the color to be used for drawing border around text. For the syntax of this
5826 option, check the "Color" section in the ffmpeg-utils manual.
5828 The default value of @var{bordercolor} is "black".
5831 Select how the @var{text} is expanded. Can be either @code{none},
5832 @code{strftime} (deprecated) or
5833 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
5837 If true, check and fix text coords to avoid clipping.
5840 The color to be used for drawing fonts. For the syntax of this option, check
5841 the "Color" section in the ffmpeg-utils manual.
5843 The default value of @var{fontcolor} is "black".
5845 @item fontcolor_expr
5846 String which is expanded the same way as @var{text} to obtain dynamic
5847 @var{fontcolor} value. By default this option has empty value and is not
5848 processed. When this option is set, it overrides @var{fontcolor} option.
5851 The font family to be used for drawing text. By default Sans.
5854 The font file to be used for drawing text. The path must be included.
5855 This parameter is mandatory if the fontconfig support is disabled.
5858 This option does not exist, please see the timeline system
5861 Draw the text applying alpha blending. The value can
5862 be either a number between 0.0 and 1.0
5863 The expression accepts the same variables @var{x, y} do.
5864 The default value is 1.
5865 Please see fontcolor_expr
5868 The font size to be used for drawing text.
5869 The default value of @var{fontsize} is 16.
5872 If set to 1, attempt to shape the text (for example, reverse the order of
5873 right-to-left text and join Arabic characters) before drawing it.
5874 Otherwise, just draw the text exactly as given.
5875 By default 1 (if supported).
5878 The flags to be used for loading the fonts.
5880 The flags map the corresponding flags supported by libfreetype, and are
5881 a combination of the following values:
5888 @item vertical_layout
5889 @item force_autohint
5892 @item ignore_global_advance_width
5894 @item ignore_transform
5900 Default value is "default".
5902 For more information consult the documentation for the FT_LOAD_*
5906 The color to be used for drawing a shadow behind the drawn text. For the
5907 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
5909 The default value of @var{shadowcolor} is "black".
5913 The x and y offsets for the text shadow position with respect to the
5914 position of the text. They can be either positive or negative
5915 values. The default value for both is "0".
5918 The starting frame number for the n/frame_num variable. The default value
5922 The size in number of spaces to use for rendering the tab.
5926 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
5927 format. It can be used with or without text parameter. @var{timecode_rate}
5928 option must be specified.
5930 @item timecode_rate, rate, r
5931 Set the timecode frame rate (timecode only).
5934 The text string to be drawn. The text must be a sequence of UTF-8
5936 This parameter is mandatory if no file is specified with the parameter
5940 A text file containing text to be drawn. The text must be a sequence
5941 of UTF-8 encoded characters.
5943 This parameter is mandatory if no text string is specified with the
5944 parameter @var{text}.
5946 If both @var{text} and @var{textfile} are specified, an error is thrown.
5949 If set to 1, the @var{textfile} will be reloaded before each frame.
5950 Be sure to update it atomically, or it may be read partially, or even fail.
5954 The expressions which specify the offsets where text will be drawn
5955 within the video frame. They are relative to the top/left border of the
5958 The default value of @var{x} and @var{y} is "0".
5960 See below for the list of accepted constants and functions.
5963 The parameters for @var{x} and @var{y} are expressions containing the
5964 following constants and functions:
5968 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
5972 horizontal and vertical chroma subsample values. For example for the
5973 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5976 the height of each text line
5984 @item max_glyph_a, ascent
5985 the maximum distance from the baseline to the highest/upper grid
5986 coordinate used to place a glyph outline point, for all the rendered
5988 It is a positive value, due to the grid's orientation with the Y axis
5991 @item max_glyph_d, descent
5992 the maximum distance from the baseline to the lowest grid coordinate
5993 used to place a glyph outline point, for all the rendered glyphs.
5994 This is a negative value, due to the grid's orientation, with the Y axis
5998 maximum glyph height, that is the maximum height for all the glyphs
5999 contained in the rendered text, it is equivalent to @var{ascent} -
6003 maximum glyph width, that is the maximum width for all the glyphs
6004 contained in the rendered text
6007 the number of input frame, starting from 0
6009 @item rand(min, max)
6010 return a random number included between @var{min} and @var{max}
6013 The input sample aspect ratio.
6016 timestamp expressed in seconds, NAN if the input timestamp is unknown
6019 the height of the rendered text
6022 the width of the rendered text
6026 the x and y offset coordinates where the text is drawn.
6028 These parameters allow the @var{x} and @var{y} expressions to refer
6029 each other, so you can for example specify @code{y=x/dar}.
6032 @anchor{drawtext_expansion}
6033 @subsection Text expansion
6035 If @option{expansion} is set to @code{strftime},
6036 the filter recognizes strftime() sequences in the provided text and
6037 expands them accordingly. Check the documentation of strftime(). This
6038 feature is deprecated.
6040 If @option{expansion} is set to @code{none}, the text is printed verbatim.
6042 If @option{expansion} is set to @code{normal} (which is the default),
6043 the following expansion mechanism is used.
6045 The backslash character @samp{\}, followed by any character, always expands to
6046 the second character.
6048 Sequence of the form @code{%@{...@}} are expanded. The text between the
6049 braces is a function name, possibly followed by arguments separated by ':'.
6050 If the arguments contain special characters or delimiters (':' or '@}'),
6051 they should be escaped.
6053 Note that they probably must also be escaped as the value for the
6054 @option{text} option in the filter argument string and as the filter
6055 argument in the filtergraph description, and possibly also for the shell,
6056 that makes up to four levels of escaping; using a text file avoids these
6059 The following functions are available:
6064 The expression evaluation result.
6066 It must take one argument specifying the expression to be evaluated,
6067 which accepts the same constants and functions as the @var{x} and
6068 @var{y} values. Note that not all constants should be used, for
6069 example the text size is not known when evaluating the expression, so
6070 the constants @var{text_w} and @var{text_h} will have an undefined
6073 @item expr_int_format, eif
6074 Evaluate the expression's value and output as formatted integer.
6076 The first argument is the expression to be evaluated, just as for the @var{expr} function.
6077 The second argument specifies the output format. Allowed values are @samp{x},
6078 @samp{X}, @samp{d} and @samp{u}. They are treated exactly as in the
6079 @code{printf} function.
6080 The third parameter is optional and sets the number of positions taken by the output.
6081 It can be used to add padding with zeros from the left.
6084 The time at which the filter is running, expressed in UTC.
6085 It can accept an argument: a strftime() format string.
6088 The time at which the filter is running, expressed in the local time zone.
6089 It can accept an argument: a strftime() format string.
6092 Frame metadata. It must take one argument specifying metadata key.
6095 The frame number, starting from 0.
6098 A 1 character description of the current picture type.
6101 The timestamp of the current frame.
6102 It can take up to three arguments.
6104 The first argument is the format of the timestamp; it defaults to @code{flt}
6105 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
6106 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
6107 @code{gmtime} stands for the timestamp of the frame formatted as UTC time;
6108 @code{localtime} stands for the timestamp of the frame formatted as
6109 local time zone time.
6111 The second argument is an offset added to the timestamp.
6113 If the format is set to @code{localtime} or @code{gmtime},
6114 a third argument may be supplied: a strftime() format string.
6115 By default, @var{YYYY-MM-DD HH:MM:SS} format will be used.
6118 @subsection Examples
6122 Draw "Test Text" with font FreeSerif, using the default values for the
6123 optional parameters.
6126 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
6130 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
6131 and y=50 (counting from the top-left corner of the screen), text is
6132 yellow with a red box around it. Both the text and the box have an
6136 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
6137 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
6140 Note that the double quotes are not necessary if spaces are not used
6141 within the parameter list.
6144 Show the text at the center of the video frame:
6146 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h)/2"
6150 Show a text line sliding from right to left in the last row of the video
6151 frame. The file @file{LONG_LINE} is assumed to contain a single line
6154 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
6158 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
6160 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
6164 Draw a single green letter "g", at the center of the input video.
6165 The glyph baseline is placed at half screen height.
6167 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
6171 Show text for 1 second every 3 seconds:
6173 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
6177 Use fontconfig to set the font. Note that the colons need to be escaped.
6179 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
6183 Print the date of a real-time encoding (see strftime(3)):
6185 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
6189 Show text fading in and out (appearing/disappearing):
6192 DS=1.0 # display start
6193 DE=10.0 # display end
6194 FID=1.5 # fade in duration
6195 FOD=5 # fade out duration
6196 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 @}"
6201 For more information about libfreetype, check:
6202 @url{http://www.freetype.org/}.
6204 For more information about fontconfig, check:
6205 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
6207 For more information about libfribidi, check:
6208 @url{http://fribidi.org/}.
6212 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
6214 The filter accepts the following options:
6219 Set low and high threshold values used by the Canny thresholding
6222 The high threshold selects the "strong" edge pixels, which are then
6223 connected through 8-connectivity with the "weak" edge pixels selected
6224 by the low threshold.
6226 @var{low} and @var{high} threshold values must be chosen in the range
6227 [0,1], and @var{low} should be lesser or equal to @var{high}.
6229 Default value for @var{low} is @code{20/255}, and default value for @var{high}
6233 Define the drawing mode.
6237 Draw white/gray wires on black background.
6240 Mix the colors to create a paint/cartoon effect.
6243 Default value is @var{wires}.
6246 @subsection Examples
6250 Standard edge detection with custom values for the hysteresis thresholding:
6252 edgedetect=low=0.1:high=0.4
6256 Painting effect without thresholding:
6258 edgedetect=mode=colormix:high=0
6263 Set brightness, contrast, saturation and approximate gamma adjustment.
6265 The filter accepts the following options:
6269 Set the contrast expression. The value must be a float value in range
6270 @code{-2.0} to @code{2.0}. The default value is "1".
6273 Set the brightness expression. The value must be a float value in
6274 range @code{-1.0} to @code{1.0}. The default value is "0".
6277 Set the saturation expression. The value must be a float in
6278 range @code{0.0} to @code{3.0}. The default value is "1".
6281 Set the gamma expression. The value must be a float in range
6282 @code{0.1} to @code{10.0}. The default value is "1".
6285 Set the gamma expression for red. The value must be a float in
6286 range @code{0.1} to @code{10.0}. The default value is "1".
6289 Set the gamma expression for green. The value must be a float in range
6290 @code{0.1} to @code{10.0}. The default value is "1".
6293 Set the gamma expression for blue. The value must be a float in range
6294 @code{0.1} to @code{10.0}. The default value is "1".
6297 Set the gamma weight expression. It can be used to reduce the effect
6298 of a high gamma value on bright image areas, e.g. keep them from
6299 getting overamplified and just plain white. The value must be a float
6300 in range @code{0.0} to @code{1.0}. A value of @code{0.0} turns the
6301 gamma correction all the way down while @code{1.0} leaves it at its
6302 full strength. Default is "1".
6305 Set when the expressions for brightness, contrast, saturation and
6306 gamma expressions are evaluated.
6308 It accepts the following values:
6311 only evaluate expressions once during the filter initialization or
6312 when a command is processed
6315 evaluate expressions for each incoming frame
6318 Default value is @samp{init}.
6321 The expressions accept the following parameters:
6324 frame count of the input frame starting from 0
6327 byte position of the corresponding packet in the input file, NAN if
6331 frame rate of the input video, NAN if the input frame rate is unknown
6334 timestamp expressed in seconds, NAN if the input timestamp is unknown
6337 @subsection Commands
6338 The filter supports the following commands:
6342 Set the contrast expression.
6345 Set the brightness expression.
6348 Set the saturation expression.
6351 Set the gamma expression.
6354 Set the gamma_r expression.
6357 Set gamma_g expression.
6360 Set gamma_b expression.
6363 Set gamma_weight expression.
6365 The command accepts the same syntax of the corresponding option.
6367 If the specified expression is not valid, it is kept at its current
6374 Apply erosion effect to the video.
6376 This filter replaces the pixel by the local(3x3) minimum.
6378 It accepts the following options:
6385 Limit the maximum change for each plane, default is 65535.
6386 If 0, plane will remain unchanged.
6389 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
6392 Flags to local 3x3 coordinates maps like this:
6399 @section extractplanes
6401 Extract color channel components from input video stream into
6402 separate grayscale video streams.
6404 The filter accepts the following option:
6408 Set plane(s) to extract.
6410 Available values for planes are:
6421 Choosing planes not available in the input will result in an error.
6422 That means you cannot select @code{r}, @code{g}, @code{b} planes
6423 with @code{y}, @code{u}, @code{v} planes at same time.
6426 @subsection Examples
6430 Extract luma, u and v color channel component from input video frame
6431 into 3 grayscale outputs:
6433 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
6439 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
6441 For each input image, the filter will compute the optimal mapping from
6442 the input to the output given the codebook length, that is the number
6443 of distinct output colors.
6445 This filter accepts the following options.
6448 @item codebook_length, l
6449 Set codebook length. The value must be a positive integer, and
6450 represents the number of distinct output colors. Default value is 256.
6453 Set the maximum number of iterations to apply for computing the optimal
6454 mapping. The higher the value the better the result and the higher the
6455 computation time. Default value is 1.
6458 Set a random seed, must be an integer included between 0 and
6459 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
6460 will try to use a good random seed on a best effort basis.
6463 Set pal8 output pixel format. This option does not work with codebook
6464 length greater than 256.
6469 Apply a fade-in/out effect to the input video.
6471 It accepts the following parameters:
6475 The effect type can be either "in" for a fade-in, or "out" for a fade-out
6477 Default is @code{in}.
6479 @item start_frame, s
6480 Specify the number of the frame to start applying the fade
6481 effect at. Default is 0.
6484 The number of frames that the fade effect lasts. At the end of the
6485 fade-in effect, the output video will have the same intensity as the input video.
6486 At the end of the fade-out transition, the output video will be filled with the
6487 selected @option{color}.
6491 If set to 1, fade only alpha channel, if one exists on the input.
6494 @item start_time, st
6495 Specify the timestamp (in seconds) of the frame to start to apply the fade
6496 effect. If both start_frame and start_time are specified, the fade will start at
6497 whichever comes last. Default is 0.
6500 The number of seconds for which the fade effect has to last. At the end of the
6501 fade-in effect the output video will have the same intensity as the input video,
6502 at the end of the fade-out transition the output video will be filled with the
6503 selected @option{color}.
6504 If both duration and nb_frames are specified, duration is used. Default is 0
6505 (nb_frames is used by default).
6508 Specify the color of the fade. Default is "black".
6511 @subsection Examples
6515 Fade in the first 30 frames of video:
6520 The command above is equivalent to:
6526 Fade out the last 45 frames of a 200-frame video:
6529 fade=type=out:start_frame=155:nb_frames=45
6533 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
6535 fade=in:0:25, fade=out:975:25
6539 Make the first 5 frames yellow, then fade in from frame 5-24:
6541 fade=in:5:20:color=yellow
6545 Fade in alpha over first 25 frames of video:
6547 fade=in:0:25:alpha=1
6551 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
6553 fade=t=in:st=5.5:d=0.5
6559 Apply arbitrary expressions to samples in frequency domain
6563 Adjust the dc value (gain) of the luma plane of the image. The filter
6564 accepts an integer value in range @code{0} to @code{1000}. The default
6565 value is set to @code{0}.
6568 Adjust the dc value (gain) of the 1st chroma plane of the image. The
6569 filter accepts an integer value in range @code{0} to @code{1000}. The
6570 default value is set to @code{0}.
6573 Adjust the dc value (gain) of the 2nd chroma plane of the image. The
6574 filter accepts an integer value in range @code{0} to @code{1000}. The
6575 default value is set to @code{0}.
6578 Set the frequency domain weight expression for the luma plane.
6581 Set the frequency domain weight expression for the 1st chroma plane.
6584 Set the frequency domain weight expression for the 2nd chroma plane.
6586 The filter accepts the following variables:
6589 The coordinates of the current sample.
6593 The width and height of the image.
6596 @subsection Examples
6602 fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
6608 fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
6614 fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
6620 fftfilt=dc_Y=0:weight_Y='exp(-4 * ((Y+X)/(W+H)))'
6627 Extract a single field from an interlaced image using stride
6628 arithmetic to avoid wasting CPU time. The output frames are marked as
6631 The filter accepts the following options:
6635 Specify whether to extract the top (if the value is @code{0} or
6636 @code{top}) or the bottom field (if the value is @code{1} or
6642 Create new frames by copying the top and bottom fields from surrounding frames
6643 supplied as numbers by the hint file.
6647 Set file containing hints: absolute/relative frame numbers.
6649 There must be one line for each frame in a clip. Each line must contain two
6650 numbers separated by the comma, optionally followed by @code{-} or @code{+}.
6651 Numbers supplied on each line of file can not be out of [N-1,N+1] where N
6652 is current frame number for @code{absolute} mode or out of [-1, 1] range
6653 for @code{relative} mode. First number tells from which frame to pick up top
6654 field and second number tells from which frame to pick up bottom field.
6656 If optionally followed by @code{+} output frame will be marked as interlaced,
6657 else if followed by @code{-} output frame will be marked as progressive, else
6658 it will be marked same as input frame.
6659 If line starts with @code{#} or @code{;} that line is skipped.
6662 Can be item @code{absolute} or @code{relative}. Default is @code{absolute}.
6665 Example of first several lines of @code{hint} file for @code{relative} mode:
6668 1,0 - # second frame, use third's frame top field and second's frame bottom field
6669 1,0 - # third frame, use fourth's frame top field and third's frame bottom field
6686 Field matching filter for inverse telecine. It is meant to reconstruct the
6687 progressive frames from a telecined stream. The filter does not drop duplicated
6688 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
6689 followed by a decimation filter such as @ref{decimate} in the filtergraph.
6691 The separation of the field matching and the decimation is notably motivated by
6692 the possibility of inserting a de-interlacing filter fallback between the two.
6693 If the source has mixed telecined and real interlaced content,
6694 @code{fieldmatch} will not be able to match fields for the interlaced parts.
6695 But these remaining combed frames will be marked as interlaced, and thus can be
6696 de-interlaced by a later filter such as @ref{yadif} before decimation.
6698 In addition to the various configuration options, @code{fieldmatch} can take an
6699 optional second stream, activated through the @option{ppsrc} option. If
6700 enabled, the frames reconstruction will be based on the fields and frames from
6701 this second stream. This allows the first input to be pre-processed in order to
6702 help the various algorithms of the filter, while keeping the output lossless
6703 (assuming the fields are matched properly). Typically, a field-aware denoiser,
6704 or brightness/contrast adjustments can help.
6706 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
6707 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
6708 which @code{fieldmatch} is based on. While the semantic and usage are very
6709 close, some behaviour and options names can differ.
6711 The @ref{decimate} filter currently only works for constant frame rate input.
6712 If your input has mixed telecined (30fps) and progressive content with a lower
6713 framerate like 24fps use the following filterchain to produce the necessary cfr
6714 stream: @code{dejudder,fps=30000/1001,fieldmatch,decimate}.
6716 The filter accepts the following options:
6720 Specify the assumed field order of the input stream. Available values are:
6724 Auto detect parity (use FFmpeg's internal parity value).
6726 Assume bottom field first.
6728 Assume top field first.
6731 Note that it is sometimes recommended not to trust the parity announced by the
6734 Default value is @var{auto}.
6737 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
6738 sense that it won't risk creating jerkiness due to duplicate frames when
6739 possible, but if there are bad edits or blended fields it will end up
6740 outputting combed frames when a good match might actually exist. On the other
6741 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
6742 but will almost always find a good frame if there is one. The other values are
6743 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
6744 jerkiness and creating duplicate frames versus finding good matches in sections
6745 with bad edits, orphaned fields, blended fields, etc.
6747 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
6749 Available values are:
6753 2-way matching (p/c)
6755 2-way matching, and trying 3rd match if still combed (p/c + n)
6757 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
6759 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
6760 still combed (p/c + n + u/b)
6762 3-way matching (p/c/n)
6764 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
6765 detected as combed (p/c/n + u/b)
6768 The parenthesis at the end indicate the matches that would be used for that
6769 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
6772 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
6775 Default value is @var{pc_n}.
6778 Mark the main input stream as a pre-processed input, and enable the secondary
6779 input stream as the clean source to pick the fields from. See the filter
6780 introduction for more details. It is similar to the @option{clip2} feature from
6783 Default value is @code{0} (disabled).
6786 Set the field to match from. It is recommended to set this to the same value as
6787 @option{order} unless you experience matching failures with that setting. In
6788 certain circumstances changing the field that is used to match from can have a
6789 large impact on matching performance. Available values are:
6793 Automatic (same value as @option{order}).
6795 Match from the bottom field.
6797 Match from the top field.
6800 Default value is @var{auto}.
6803 Set whether or not chroma is included during the match comparisons. In most
6804 cases it is recommended to leave this enabled. You should set this to @code{0}
6805 only if your clip has bad chroma problems such as heavy rainbowing or other
6806 artifacts. Setting this to @code{0} could also be used to speed things up at
6807 the cost of some accuracy.
6809 Default value is @code{1}.
6813 These define an exclusion band which excludes the lines between @option{y0} and
6814 @option{y1} from being included in the field matching decision. An exclusion
6815 band can be used to ignore subtitles, a logo, or other things that may
6816 interfere with the matching. @option{y0} sets the starting scan line and
6817 @option{y1} sets the ending line; all lines in between @option{y0} and
6818 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
6819 @option{y0} and @option{y1} to the same value will disable the feature.
6820 @option{y0} and @option{y1} defaults to @code{0}.
6823 Set the scene change detection threshold as a percentage of maximum change on
6824 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
6825 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
6826 @option{scthresh} is @code{[0.0, 100.0]}.
6828 Default value is @code{12.0}.
6831 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
6832 account the combed scores of matches when deciding what match to use as the
6833 final match. Available values are:
6837 No final matching based on combed scores.
6839 Combed scores are only used when a scene change is detected.
6841 Use combed scores all the time.
6844 Default is @var{sc}.
6847 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
6848 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
6849 Available values are:
6853 No forced calculation.
6855 Force p/c/n calculations.
6857 Force p/c/n/u/b calculations.
6860 Default value is @var{none}.
6863 This is the area combing threshold used for combed frame detection. This
6864 essentially controls how "strong" or "visible" combing must be to be detected.
6865 Larger values mean combing must be more visible and smaller values mean combing
6866 can be less visible or strong and still be detected. Valid settings are from
6867 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
6868 be detected as combed). This is basically a pixel difference value. A good
6869 range is @code{[8, 12]}.
6871 Default value is @code{9}.
6874 Sets whether or not chroma is considered in the combed frame decision. Only
6875 disable this if your source has chroma problems (rainbowing, etc.) that are
6876 causing problems for the combed frame detection with chroma enabled. Actually,
6877 using @option{chroma}=@var{0} is usually more reliable, except for the case
6878 where there is chroma only combing in the source.
6880 Default value is @code{0}.
6884 Respectively set the x-axis and y-axis size of the window used during combed
6885 frame detection. This has to do with the size of the area in which
6886 @option{combpel} pixels are required to be detected as combed for a frame to be
6887 declared combed. See the @option{combpel} parameter description for more info.
6888 Possible values are any number that is a power of 2 starting at 4 and going up
6891 Default value is @code{16}.
6894 The number of combed pixels inside any of the @option{blocky} by
6895 @option{blockx} size blocks on the frame for the frame to be detected as
6896 combed. While @option{cthresh} controls how "visible" the combing must be, this
6897 setting controls "how much" combing there must be in any localized area (a
6898 window defined by the @option{blockx} and @option{blocky} settings) on the
6899 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
6900 which point no frames will ever be detected as combed). This setting is known
6901 as @option{MI} in TFM/VFM vocabulary.
6903 Default value is @code{80}.
6906 @anchor{p/c/n/u/b meaning}
6907 @subsection p/c/n/u/b meaning
6909 @subsubsection p/c/n
6911 We assume the following telecined stream:
6914 Top fields: 1 2 2 3 4
6915 Bottom fields: 1 2 3 4 4
6918 The numbers correspond to the progressive frame the fields relate to. Here, the
6919 first two frames are progressive, the 3rd and 4th are combed, and so on.
6921 When @code{fieldmatch} is configured to run a matching from bottom
6922 (@option{field}=@var{bottom}) this is how this input stream get transformed:
6927 B 1 2 3 4 4 <-- matching reference
6936 As a result of the field matching, we can see that some frames get duplicated.
6937 To perform a complete inverse telecine, you need to rely on a decimation filter
6938 after this operation. See for instance the @ref{decimate} filter.
6940 The same operation now matching from top fields (@option{field}=@var{top})
6945 T 1 2 2 3 4 <-- matching reference
6955 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
6956 basically, they refer to the frame and field of the opposite parity:
6959 @item @var{p} matches the field of the opposite parity in the previous frame
6960 @item @var{c} matches the field of the opposite parity in the current frame
6961 @item @var{n} matches the field of the opposite parity in the next frame
6966 The @var{u} and @var{b} matching are a bit special in the sense that they match
6967 from the opposite parity flag. In the following examples, we assume that we are
6968 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
6969 'x' is placed above and below each matched fields.
6971 With bottom matching (@option{field}=@var{bottom}):
6976 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
6977 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
6985 With top matching (@option{field}=@var{top}):
6990 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
6991 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
6999 @subsection Examples
7001 Simple IVTC of a top field first telecined stream:
7003 fieldmatch=order=tff:combmatch=none, decimate
7006 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
7008 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
7013 Transform the field order of the input video.
7015 It accepts the following parameters:
7020 The output field order. Valid values are @var{tff} for top field first or @var{bff}
7021 for bottom field first.
7024 The default value is @samp{tff}.
7026 The transformation is done by shifting the picture content up or down
7027 by one line, and filling the remaining line with appropriate picture content.
7028 This method is consistent with most broadcast field order converters.
7030 If the input video is not flagged as being interlaced, or it is already
7031 flagged as being of the required output field order, then this filter does
7032 not alter the incoming video.
7034 It is very useful when converting to or from PAL DV material,
7035 which is bottom field first.
7039 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
7042 @section fifo, afifo
7044 Buffer input images and send them when they are requested.
7046 It is mainly useful when auto-inserted by the libavfilter
7049 It does not take parameters.
7053 Find a rectangular object
7055 It accepts the following options:
7059 Filepath of the object image, needs to be in gray8.
7062 Detection threshold, default is 0.5.
7065 Number of mipmaps, default is 3.
7067 @item xmin, ymin, xmax, ymax
7068 Specifies the rectangle in which to search.
7071 @subsection Examples
7075 Generate a representative palette of a given video using @command{ffmpeg}:
7077 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
7083 Cover a rectangular object
7085 It accepts the following options:
7089 Filepath of the optional cover image, needs to be in yuv420.
7094 It accepts the following values:
7097 cover it by the supplied image
7099 cover it by interpolating the surrounding pixels
7102 Default value is @var{blur}.
7105 @subsection Examples
7109 Generate a representative palette of a given video using @command{ffmpeg}:
7111 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
7118 Convert the input video to one of the specified pixel formats.
7119 Libavfilter will try to pick one that is suitable as input to
7122 It accepts the following parameters:
7126 A '|'-separated list of pixel format names, such as
7127 "pix_fmts=yuv420p|monow|rgb24".
7131 @subsection Examples
7135 Convert the input video to the @var{yuv420p} format
7137 format=pix_fmts=yuv420p
7140 Convert the input video to any of the formats in the list
7142 format=pix_fmts=yuv420p|yuv444p|yuv410p
7149 Convert the video to specified constant frame rate by duplicating or dropping
7150 frames as necessary.
7152 It accepts the following parameters:
7156 The desired output frame rate. The default is @code{25}.
7161 Possible values are:
7164 zero round towards 0
7168 round towards -infinity
7170 round towards +infinity
7174 The default is @code{near}.
7177 Assume the first PTS should be the given value, in seconds. This allows for
7178 padding/trimming at the start of stream. By default, no assumption is made
7179 about the first frame's expected PTS, so no padding or trimming is done.
7180 For example, this could be set to 0 to pad the beginning with duplicates of
7181 the first frame if a video stream starts after the audio stream or to trim any
7182 frames with a negative PTS.
7186 Alternatively, the options can be specified as a flat string:
7187 @var{fps}[:@var{round}].
7189 See also the @ref{setpts} filter.
7191 @subsection Examples
7195 A typical usage in order to set the fps to 25:
7201 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
7203 fps=fps=film:round=near
7209 Pack two different video streams into a stereoscopic video, setting proper
7210 metadata on supported codecs. The two views should have the same size and
7211 framerate and processing will stop when the shorter video ends. Please note
7212 that you may conveniently adjust view properties with the @ref{scale} and
7215 It accepts the following parameters:
7219 The desired packing format. Supported values are:
7224 The views are next to each other (default).
7227 The views are on top of each other.
7230 The views are packed by line.
7233 The views are packed by column.
7236 The views are temporally interleaved.
7245 # Convert left and right views into a frame-sequential video
7246 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
7248 # Convert views into a side-by-side video with the same output resolution as the input
7249 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
7254 Change the frame rate by interpolating new video output frames from the source
7257 This filter is not designed to function correctly with interlaced media. If
7258 you wish to change the frame rate of interlaced media then you are required
7259 to deinterlace before this filter and re-interlace after this filter.
7261 A description of the accepted options follows.
7265 Specify the output frames per second. This option can also be specified
7266 as a value alone. The default is @code{50}.
7269 Specify the start of a range where the output frame will be created as a
7270 linear interpolation of two frames. The range is [@code{0}-@code{255}],
7271 the default is @code{15}.
7274 Specify the end of a range where the output frame will be created as a
7275 linear interpolation of two frames. The range is [@code{0}-@code{255}],
7276 the default is @code{240}.
7279 Specify the level at which a scene change is detected as a value between
7280 0 and 100 to indicate a new scene; a low value reflects a low
7281 probability for the current frame to introduce a new scene, while a higher
7282 value means the current frame is more likely to be one.
7283 The default is @code{7}.
7286 Specify flags influencing the filter process.
7288 Available value for @var{flags} is:
7291 @item scene_change_detect, scd
7292 Enable scene change detection using the value of the option @var{scene}.
7293 This flag is enabled by default.
7299 Select one frame every N-th frame.
7301 This filter accepts the following option:
7304 Select frame after every @code{step} frames.
7305 Allowed values are positive integers higher than 0. Default value is @code{1}.
7311 Apply a frei0r effect to the input video.
7313 To enable the compilation of this filter, you need to install the frei0r
7314 header and configure FFmpeg with @code{--enable-frei0r}.
7316 It accepts the following parameters:
7321 The name of the frei0r effect to load. If the environment variable
7322 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
7323 directories specified by the colon-separated list in @env{FREIOR_PATH}.
7324 Otherwise, the standard frei0r paths are searched, in this order:
7325 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
7326 @file{/usr/lib/frei0r-1/}.
7329 A '|'-separated list of parameters to pass to the frei0r effect.
7333 A frei0r effect parameter can be a boolean (its value is either
7334 "y" or "n"), a double, a color (specified as
7335 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
7336 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
7337 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
7338 @var{X} and @var{Y} are floating point numbers) and/or a string.
7340 The number and types of parameters depend on the loaded effect. If an
7341 effect parameter is not specified, the default value is set.
7343 @subsection Examples
7347 Apply the distort0r effect, setting the first two double parameters:
7349 frei0r=filter_name=distort0r:filter_params=0.5|0.01
7353 Apply the colordistance effect, taking a color as the first parameter:
7355 frei0r=colordistance:0.2/0.3/0.4
7356 frei0r=colordistance:violet
7357 frei0r=colordistance:0x112233
7361 Apply the perspective effect, specifying the top left and top right image
7364 frei0r=perspective:0.2/0.2|0.8/0.2
7368 For more information, see
7369 @url{http://frei0r.dyne.org}
7373 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
7375 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
7376 processing filter, one of them is performed once per block, not per pixel.
7377 This allows for much higher speed.
7379 The filter accepts the following options:
7383 Set quality. This option defines the number of levels for averaging. It accepts
7384 an integer in the range 4-5. Default value is @code{4}.
7387 Force a constant quantization parameter. It accepts an integer in range 0-63.
7388 If not set, the filter will use the QP from the video stream (if available).
7391 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
7392 more details but also more artifacts, while higher values make the image smoother
7393 but also blurrier. Default value is @code{0} − PSNR optimal.
7396 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
7397 option may cause flicker since the B-Frames have often larger QP. Default is
7398 @code{0} (not enabled).
7404 The filter accepts the following options:
7408 Set the luminance expression.
7410 Set the chrominance blue expression.
7412 Set the chrominance red expression.
7414 Set the alpha expression.
7416 Set the red expression.
7418 Set the green expression.
7420 Set the blue expression.
7423 The colorspace is selected according to the specified options. If one
7424 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
7425 options is specified, the filter will automatically select a YCbCr
7426 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
7427 @option{blue_expr} options is specified, it will select an RGB
7430 If one of the chrominance expression is not defined, it falls back on the other
7431 one. If no alpha expression is specified it will evaluate to opaque value.
7432 If none of chrominance expressions are specified, they will evaluate
7433 to the luminance expression.
7435 The expressions can use the following variables and functions:
7439 The sequential number of the filtered frame, starting from @code{0}.
7443 The coordinates of the current sample.
7447 The width and height of the image.
7451 Width and height scale depending on the currently filtered plane. It is the
7452 ratio between the corresponding luma plane number of pixels and the current
7453 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
7454 @code{0.5,0.5} for chroma planes.
7457 Time of the current frame, expressed in seconds.
7460 Return the value of the pixel at location (@var{x},@var{y}) of the current
7464 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
7468 Return the value of the pixel at location (@var{x},@var{y}) of the
7469 blue-difference chroma plane. Return 0 if there is no such plane.
7472 Return the value of the pixel at location (@var{x},@var{y}) of the
7473 red-difference chroma plane. Return 0 if there is no such plane.
7478 Return the value of the pixel at location (@var{x},@var{y}) of the
7479 red/green/blue component. Return 0 if there is no such component.
7482 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
7483 plane. Return 0 if there is no such plane.
7486 For functions, if @var{x} and @var{y} are outside the area, the value will be
7487 automatically clipped to the closer edge.
7489 @subsection Examples
7493 Flip the image horizontally:
7499 Generate a bidimensional sine wave, with angle @code{PI/3} and a
7500 wavelength of 100 pixels:
7502 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
7506 Generate a fancy enigmatic moving light:
7508 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
7512 Generate a quick emboss effect:
7514 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
7518 Modify RGB components depending on pixel position:
7520 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
7524 Create a radial gradient that is the same size as the input (also see
7525 the @ref{vignette} filter):
7527 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
7531 Diagonal split screen to compare filter effect:
7533 ffmpeg -i input -filter_complex "[0:v]geq=lum=if(gt(X\,Y*(W/H))\,255),format=gray[alpha];[0:v][alpha]alphamerge,curves=preset=color_negative[filtered];[0:v][filtered]overlay" output
7539 Fix the banding artifacts that are sometimes introduced into nearly flat
7540 regions by truncation to 8bit color depth.
7541 Interpolate the gradients that should go where the bands are, and
7544 It is designed for playback only. Do not use it prior to
7545 lossy compression, because compression tends to lose the dither and
7546 bring back the bands.
7548 It accepts the following parameters:
7553 The maximum amount by which the filter will change any one pixel. This is also
7554 the threshold for detecting nearly flat regions. Acceptable values range from
7555 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
7559 The neighborhood to fit the gradient to. A larger radius makes for smoother
7560 gradients, but also prevents the filter from modifying the pixels near detailed
7561 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
7562 values will be clipped to the valid range.
7566 Alternatively, the options can be specified as a flat string:
7567 @var{strength}[:@var{radius}]
7569 @subsection Examples
7573 Apply the filter with a @code{3.5} strength and radius of @code{8}:
7579 Specify radius, omitting the strength (which will fall-back to the default
7590 Apply a Hald CLUT to a video stream.
7592 First input is the video stream to process, and second one is the Hald CLUT.
7593 The Hald CLUT input can be a simple picture or a complete video stream.
7595 The filter accepts the following options:
7599 Force termination when the shortest input terminates. Default is @code{0}.
7601 Continue applying the last CLUT after the end of the stream. A value of
7602 @code{0} disable the filter after the last frame of the CLUT is reached.
7603 Default is @code{1}.
7606 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
7607 filters share the same internals).
7609 More information about the Hald CLUT can be found on Eskil Steenberg's website
7610 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
7612 @subsection Workflow examples
7614 @subsubsection Hald CLUT video stream
7616 Generate an identity Hald CLUT stream altered with various effects:
7618 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
7621 Note: make sure you use a lossless codec.
7623 Then use it with @code{haldclut} to apply it on some random stream:
7625 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
7628 The Hald CLUT will be applied to the 10 first seconds (duration of
7629 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
7630 to the remaining frames of the @code{mandelbrot} stream.
7632 @subsubsection Hald CLUT with preview
7634 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
7635 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
7636 biggest possible square starting at the top left of the picture. The remaining
7637 padding pixels (bottom or right) will be ignored. This area can be used to add
7638 a preview of the Hald CLUT.
7640 Typically, the following generated Hald CLUT will be supported by the
7641 @code{haldclut} filter:
7644 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
7645 pad=iw+320 [padded_clut];
7646 smptebars=s=320x256, split [a][b];
7647 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
7648 [main][b] overlay=W-320" -frames:v 1 clut.png
7651 It contains the original and a preview of the effect of the CLUT: SMPTE color
7652 bars are displayed on the right-top, and below the same color bars processed by
7655 Then, the effect of this Hald CLUT can be visualized with:
7657 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
7662 Flip the input video horizontally.
7664 For example, to horizontally flip the input video with @command{ffmpeg}:
7666 ffmpeg -i in.avi -vf "hflip" out.avi
7670 This filter applies a global color histogram equalization on a
7673 It can be used to correct video that has a compressed range of pixel
7674 intensities. The filter redistributes the pixel intensities to
7675 equalize their distribution across the intensity range. It may be
7676 viewed as an "automatically adjusting contrast filter". This filter is
7677 useful only for correcting degraded or poorly captured source
7680 The filter accepts the following options:
7684 Determine the amount of equalization to be applied. As the strength
7685 is reduced, the distribution of pixel intensities more-and-more
7686 approaches that of the input frame. The value must be a float number
7687 in the range [0,1] and defaults to 0.200.
7690 Set the maximum intensity that can generated and scale the output
7691 values appropriately. The strength should be set as desired and then
7692 the intensity can be limited if needed to avoid washing-out. The value
7693 must be a float number in the range [0,1] and defaults to 0.210.
7696 Set the antibanding level. If enabled the filter will randomly vary
7697 the luminance of output pixels by a small amount to avoid banding of
7698 the histogram. Possible values are @code{none}, @code{weak} or
7699 @code{strong}. It defaults to @code{none}.
7704 Compute and draw a color distribution histogram for the input video.
7706 The computed histogram is a representation of the color component
7707 distribution in an image.
7709 Standard histogram displays the color components distribution in an image.
7710 Displays color graph for each color component. Shows distribution of
7711 the Y, U, V, A or R, G, B components, depending on input format, in the
7712 current frame. Below each graph a color component scale meter is shown.
7714 The filter accepts the following options:
7718 Set height of level. Default value is @code{200}.
7719 Allowed range is [50, 2048].
7722 Set height of color scale. Default value is @code{12}.
7723 Allowed range is [0, 40].
7727 It accepts the following values:
7730 Per color component graphs are placed below each other.
7733 Presents information identical to that in the @code{parade}, except
7734 that the graphs representing color components are superimposed directly
7737 Default is @code{parade}.
7740 Set mode. Can be either @code{linear}, or @code{logarithmic}.
7741 Default is @code{linear}.
7744 Set what color components to display.
7745 Default is @code{7}.
7748 @subsection Examples
7753 Calculate and draw histogram:
7755 ffplay -i input -vf histogram
7763 This is a high precision/quality 3d denoise filter. It aims to reduce
7764 image noise, producing smooth images and making still images really
7765 still. It should enhance compressibility.
7767 It accepts the following optional parameters:
7771 A non-negative floating point number which specifies spatial luma strength.
7774 @item chroma_spatial
7775 A non-negative floating point number which specifies spatial chroma strength.
7776 It defaults to 3.0*@var{luma_spatial}/4.0.
7779 A floating point number which specifies luma temporal strength. It defaults to
7780 6.0*@var{luma_spatial}/4.0.
7783 A floating point number which specifies chroma temporal strength. It defaults to
7784 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
7789 Apply a high-quality magnification filter designed for pixel art. This filter
7790 was originally created by Maxim Stepin.
7792 It accepts the following option:
7796 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
7797 @code{hq3x} and @code{4} for @code{hq4x}.
7798 Default is @code{3}.
7802 Stack input videos horizontally.
7804 All streams must be of same pixel format and of same height.
7806 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
7807 to create same output.
7809 The filter accept the following option:
7813 Set number of input streams. Default is 2.
7816 If set to 1, force the output to terminate when the shortest input
7817 terminates. Default value is 0.
7822 Modify the hue and/or the saturation of the input.
7824 It accepts the following parameters:
7828 Specify the hue angle as a number of degrees. It accepts an expression,
7829 and defaults to "0".
7832 Specify the saturation in the [-10,10] range. It accepts an expression and
7836 Specify the hue angle as a number of radians. It accepts an
7837 expression, and defaults to "0".
7840 Specify the brightness in the [-10,10] range. It accepts an expression and
7844 @option{h} and @option{H} are mutually exclusive, and can't be
7845 specified at the same time.
7847 The @option{b}, @option{h}, @option{H} and @option{s} option values are
7848 expressions containing the following constants:
7852 frame count of the input frame starting from 0
7855 presentation timestamp of the input frame expressed in time base units
7858 frame rate of the input video, NAN if the input frame rate is unknown
7861 timestamp expressed in seconds, NAN if the input timestamp is unknown
7864 time base of the input video
7867 @subsection Examples
7871 Set the hue to 90 degrees and the saturation to 1.0:
7877 Same command but expressing the hue in radians:
7883 Rotate hue and make the saturation swing between 0
7884 and 2 over a period of 1 second:
7886 hue="H=2*PI*t: s=sin(2*PI*t)+1"
7890 Apply a 3 seconds saturation fade-in effect starting at 0:
7895 The general fade-in expression can be written as:
7897 hue="s=min(0\, max((t-START)/DURATION\, 1))"
7901 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
7903 hue="s=max(0\, min(1\, (8-t)/3))"
7906 The general fade-out expression can be written as:
7908 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
7913 @subsection Commands
7915 This filter supports the following commands:
7921 Modify the hue and/or the saturation and/or brightness of the input video.
7922 The command accepts the same syntax of the corresponding option.
7924 If the specified expression is not valid, it is kept at its current
7930 Detect video interlacing type.
7932 This filter tries to detect if the input frames as interlaced, progressive,
7933 top or bottom field first. It will also try and detect fields that are
7934 repeated between adjacent frames (a sign of telecine).
7936 Single frame detection considers only immediately adjacent frames when classifying each frame.
7937 Multiple frame detection incorporates the classification history of previous frames.
7939 The filter will log these metadata values:
7942 @item single.current_frame
7943 Detected type of current frame using single-frame detection. One of:
7944 ``tff'' (top field first), ``bff'' (bottom field first),
7945 ``progressive'', or ``undetermined''
7948 Cumulative number of frames detected as top field first using single-frame detection.
7951 Cumulative number of frames detected as top field first using multiple-frame detection.
7954 Cumulative number of frames detected as bottom field first using single-frame detection.
7956 @item multiple.current_frame
7957 Detected type of current frame using multiple-frame detection. One of:
7958 ``tff'' (top field first), ``bff'' (bottom field first),
7959 ``progressive'', or ``undetermined''
7962 Cumulative number of frames detected as bottom field first using multiple-frame detection.
7964 @item single.progressive
7965 Cumulative number of frames detected as progressive using single-frame detection.
7967 @item multiple.progressive
7968 Cumulative number of frames detected as progressive using multiple-frame detection.
7970 @item single.undetermined
7971 Cumulative number of frames that could not be classified using single-frame detection.
7973 @item multiple.undetermined
7974 Cumulative number of frames that could not be classified using multiple-frame detection.
7976 @item repeated.current_frame
7977 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
7979 @item repeated.neither
7980 Cumulative number of frames with no repeated field.
7983 Cumulative number of frames with the top field repeated from the previous frame's top field.
7985 @item repeated.bottom
7986 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
7989 The filter accepts the following options:
7993 Set interlacing threshold.
7995 Set progressive threshold.
7997 Threshold for repeated field detection.
7999 Number of frames after which a given frame's contribution to the
8000 statistics is halved (i.e., it contributes only 0.5 to it's
8001 classification). The default of 0 means that all frames seen are given
8002 full weight of 1.0 forever.
8003 @item analyze_interlaced_flag
8004 When this is not 0 then idet will use the specified number of frames to determine
8005 if the interlaced flag is accurate, it will not count undetermined frames.
8006 If the flag is found to be accurate it will be used without any further
8007 computations, if it is found to be inaccurate it will be cleared without any
8008 further computations. This allows inserting the idet filter as a low computational
8009 method to clean up the interlaced flag
8014 Deinterleave or interleave fields.
8016 This filter allows one to process interlaced images fields without
8017 deinterlacing them. Deinterleaving splits the input frame into 2
8018 fields (so called half pictures). Odd lines are moved to the top
8019 half of the output image, even lines to the bottom half.
8020 You can process (filter) them independently and then re-interleave them.
8022 The filter accepts the following options:
8026 @item chroma_mode, c
8028 Available values for @var{luma_mode}, @var{chroma_mode} and
8029 @var{alpha_mode} are:
8035 @item deinterleave, d
8036 Deinterleave fields, placing one above the other.
8039 Interleave fields. Reverse the effect of deinterleaving.
8041 Default value is @code{none}.
8044 @item chroma_swap, cs
8045 @item alpha_swap, as
8046 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
8051 Apply inflate effect to the video.
8053 This filter replaces the pixel by the local(3x3) average by taking into account
8054 only values higher than the pixel.
8056 It accepts the following options:
8063 Limit the maximum change for each plane, default is 65535.
8064 If 0, plane will remain unchanged.
8069 Simple interlacing filter from progressive contents. This interleaves upper (or
8070 lower) lines from odd frames with lower (or upper) lines from even frames,
8071 halving the frame rate and preserving image height.
8074 Original Original New Frame
8075 Frame 'j' Frame 'j+1' (tff)
8076 ========== =========== ==================
8077 Line 0 --------------------> Frame 'j' Line 0
8078 Line 1 Line 1 ----> Frame 'j+1' Line 1
8079 Line 2 ---------------------> Frame 'j' Line 2
8080 Line 3 Line 3 ----> Frame 'j+1' Line 3
8082 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
8085 It accepts the following optional parameters:
8089 This determines whether the interlaced frame is taken from the even
8090 (tff - default) or odd (bff) lines of the progressive frame.
8093 Enable (default) or disable the vertical lowpass filter to avoid twitter
8094 interlacing and reduce moire patterns.
8099 Deinterlace input video by applying Donald Graft's adaptive kernel
8100 deinterling. Work on interlaced parts of a video to produce
8103 The description of the accepted parameters follows.
8107 Set the threshold which affects the filter's tolerance when
8108 determining if a pixel line must be processed. It must be an integer
8109 in the range [0,255] and defaults to 10. A value of 0 will result in
8110 applying the process on every pixels.
8113 Paint pixels exceeding the threshold value to white if set to 1.
8117 Set the fields order. Swap fields if set to 1, leave fields alone if
8121 Enable additional sharpening if set to 1. Default is 0.
8124 Enable twoway sharpening if set to 1. Default is 0.
8127 @subsection Examples
8131 Apply default values:
8133 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
8137 Enable additional sharpening:
8143 Paint processed pixels in white:
8149 @section lenscorrection
8151 Correct radial lens distortion
8153 This filter can be used to correct for radial distortion as can result from the use
8154 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
8155 one can use tools available for example as part of opencv or simply trial-and-error.
8156 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
8157 and extract the k1 and k2 coefficients from the resulting matrix.
8159 Note that effectively the same filter is available in the open-source tools Krita and
8160 Digikam from the KDE project.
8162 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
8163 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
8164 brightness distribution, so you may want to use both filters together in certain
8165 cases, though you will have to take care of ordering, i.e. whether vignetting should
8166 be applied before or after lens correction.
8170 The filter accepts the following options:
8174 Relative x-coordinate of the focal point of the image, and thereby the center of the
8175 distortion. This value has a range [0,1] and is expressed as fractions of the image
8178 Relative y-coordinate of the focal point of the image, and thereby the center of the
8179 distortion. This value has a range [0,1] and is expressed as fractions of the image
8182 Coefficient of the quadratic correction term. 0.5 means no correction.
8184 Coefficient of the double quadratic correction term. 0.5 means no correction.
8187 The formula that generates the correction is:
8189 @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)
8191 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
8192 distances from the focal point in the source and target images, respectively.
8197 Apply a 3D LUT to an input video.
8199 The filter accepts the following options:
8203 Set the 3D LUT file name.
8205 Currently supported formats:
8217 Select interpolation mode.
8219 Available values are:
8223 Use values from the nearest defined point.
8225 Interpolate values using the 8 points defining a cube.
8227 Interpolate values using a tetrahedron.
8231 @section lut, lutrgb, lutyuv
8233 Compute a look-up table for binding each pixel component input value
8234 to an output value, and apply it to the input video.
8236 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
8237 to an RGB input video.
8239 These filters accept the following parameters:
8242 set first pixel component expression
8244 set second pixel component expression
8246 set third pixel component expression
8248 set fourth pixel component expression, corresponds to the alpha component
8251 set red component expression
8253 set green component expression
8255 set blue component expression
8257 alpha component expression
8260 set Y/luminance component expression
8262 set U/Cb component expression
8264 set V/Cr component expression
8267 Each of them specifies the expression to use for computing the lookup table for
8268 the corresponding pixel component values.
8270 The exact component associated to each of the @var{c*} options depends on the
8273 The @var{lut} filter requires either YUV or RGB pixel formats in input,
8274 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
8276 The expressions can contain the following constants and functions:
8281 The input width and height.
8284 The input value for the pixel component.
8287 The input value, clipped to the @var{minval}-@var{maxval} range.
8290 The maximum value for the pixel component.
8293 The minimum value for the pixel component.
8296 The negated value for the pixel component value, clipped to the
8297 @var{minval}-@var{maxval} range; it corresponds to the expression
8298 "maxval-clipval+minval".
8301 The computed value in @var{val}, clipped to the
8302 @var{minval}-@var{maxval} range.
8304 @item gammaval(gamma)
8305 The computed gamma correction value of the pixel component value,
8306 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
8308 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
8312 All expressions default to "val".
8314 @subsection Examples
8320 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
8321 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
8324 The above is the same as:
8326 lutrgb="r=negval:g=negval:b=negval"
8327 lutyuv="y=negval:u=negval:v=negval"
8337 Remove chroma components, turning the video into a graytone image:
8339 lutyuv="u=128:v=128"
8343 Apply a luma burning effect:
8349 Remove green and blue components:
8355 Set a constant alpha channel value on input:
8357 format=rgba,lutrgb=a="maxval-minval/2"
8361 Correct luminance gamma by a factor of 0.5:
8363 lutyuv=y=gammaval(0.5)
8367 Discard least significant bits of luma:
8369 lutyuv=y='bitand(val, 128+64+32)'
8373 @section maskedmerge
8375 Merge the first input stream with the second input stream using per pixel
8376 weights in the third input stream.
8378 A value of 0 in the third stream pixel component means that pixel component
8379 from first stream is returned unchanged, while maximum value (eg. 255 for
8380 8-bit videos) means that pixel component from second stream is returned
8381 unchanged. Intermediate values define the amount of merging between both
8382 input stream's pixel components.
8384 This filter accepts the following options:
8387 Set which planes will be processed as bitmap, unprocessed planes will be
8388 copied from first stream.
8389 By default value 0xf, all planes will be processed.
8394 Apply motion-compensation deinterlacing.
8396 It needs one field per frame as input and must thus be used together
8397 with yadif=1/3 or equivalent.
8399 This filter accepts the following options:
8402 Set the deinterlacing mode.
8404 It accepts one of the following values:
8409 use iterative motion estimation
8411 like @samp{slow}, but use multiple reference frames.
8413 Default value is @samp{fast}.
8416 Set the picture field parity assumed for the input video. It must be
8417 one of the following values:
8421 assume top field first
8423 assume bottom field first
8426 Default value is @samp{bff}.
8429 Set per-block quantization parameter (QP) used by the internal
8432 Higher values should result in a smoother motion vector field but less
8433 optimal individual vectors. Default value is 1.
8436 @section mergeplanes
8438 Merge color channel components from several video streams.
8440 The filter accepts up to 4 input streams, and merge selected input
8441 planes to the output video.
8443 This filter accepts the following options:
8446 Set input to output plane mapping. Default is @code{0}.
8448 The mappings is specified as a bitmap. It should be specified as a
8449 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
8450 mapping for the first plane of the output stream. 'A' sets the number of
8451 the input stream to use (from 0 to 3), and 'a' the plane number of the
8452 corresponding input to use (from 0 to 3). The rest of the mappings is
8453 similar, 'Bb' describes the mapping for the output stream second
8454 plane, 'Cc' describes the mapping for the output stream third plane and
8455 'Dd' describes the mapping for the output stream fourth plane.
8458 Set output pixel format. Default is @code{yuva444p}.
8461 @subsection Examples
8465 Merge three gray video streams of same width and height into single video stream:
8467 [a0][a1][a2]mergeplanes=0x001020:yuv444p
8471 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
8473 [a0][a1]mergeplanes=0x00010210:yuva444p
8477 Swap Y and A plane in yuva444p stream:
8479 format=yuva444p,mergeplanes=0x03010200:yuva444p
8483 Swap U and V plane in yuv420p stream:
8485 format=yuv420p,mergeplanes=0x000201:yuv420p
8489 Cast a rgb24 clip to yuv444p:
8491 format=rgb24,mergeplanes=0x000102:yuv444p
8495 @section metadata, ametadata
8497 Manipulate frame metadata.
8499 This filter accepts the following options:
8503 Set mode of operation of the filter.
8505 Can be one of the following:
8509 If both @code{value} and @code{key} is set, select frames
8510 which have such metadata. If only @code{key} is set, select
8511 every frame that has such key in metadata.
8514 Add new metadata @code{key} and @code{value}. If key is already available
8518 Modify value of already present key.
8521 If @code{value} is set, delete only keys that have such value.
8522 Otherwise, delete key.
8525 Print key and its value if metadata was found. If @code{key} is not set print all
8526 metadata values available in frame.
8530 Set key used with all modes. Must be set for all modes except @code{print}.
8533 Set metadata value which will be used. This option is mandatory for
8534 @code{modify} and @code{add} mode.
8537 Which function to use when comparing metadata value and @code{value}.
8539 Can be one of following:
8543 Values are interpreted as strings, returns true if metadata value is same as @code{value}.
8546 Values are interpreted as strings, returns true if metadata value starts with
8547 the @code{value} option string.
8550 Values are interpreted as floats, returns true if metadata value is less than @code{value}.
8553 Values are interpreted as floats, returns true if @code{value} is equal with metadata value.
8556 Values are interpreted as floats, returns true if metadata value is greater than @code{value}.
8559 Values are interpreted as floats, returns true if expression from option @code{expr}
8564 Set expression which is used when @code{function} is set to @code{expr}.
8565 The expression is evaluated through the eval API and can contain the following
8570 Float representation of @code{value} from metadata key.
8573 Float representation of @code{value} as supplied by user in @code{value} option.
8577 If specified in @code{print} mode, output is written to the named file. When
8578 filename equals "-" data is written to standard output.
8579 If @code{file} option is not set, output is written to the log with AV_LOG_INFO
8583 @subsection Examples
8587 Print all metadata values for frames with key @code{lavfi.singnalstats.YDIF} with values
8591 signalstats,metadata=print:key=lavfi.signalstats.YDIF:value=0:function=expr:expr='between(VALUE1,0,1)'
8596 Drop frames that do not differ greatly from the previous frame in
8597 order to reduce frame rate.
8599 The main use of this filter is for very-low-bitrate encoding
8600 (e.g. streaming over dialup modem), but it could in theory be used for
8601 fixing movies that were inverse-telecined incorrectly.
8603 A description of the accepted options follows.
8607 Set the maximum number of consecutive frames which can be dropped (if
8608 positive), or the minimum interval between dropped frames (if
8609 negative). If the value is 0, the frame is dropped unregarding the
8610 number of previous sequentially dropped frames.
8617 Set the dropping threshold values.
8619 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
8620 represent actual pixel value differences, so a threshold of 64
8621 corresponds to 1 unit of difference for each pixel, or the same spread
8622 out differently over the block.
8624 A frame is a candidate for dropping if no 8x8 blocks differ by more
8625 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
8626 meaning the whole image) differ by more than a threshold of @option{lo}.
8628 Default value for @option{hi} is 64*12, default value for @option{lo} is
8629 64*5, and default value for @option{frac} is 0.33.
8637 It accepts an integer in input; if non-zero it negates the
8638 alpha component (if available). The default value in input is 0.
8642 Deinterlace video using neural network edge directed interpolation.
8644 This filter accepts the following options:
8648 Mandatory option, without binary file filter can not work.
8649 Currently file can be found here:
8650 https://github.com/dubhater/vapoursynth-nnedi3/blob/master/src/nnedi3_weights.bin
8653 Set which frames to deinterlace, by default it is @code{all}.
8654 Can be @code{all} or @code{interlaced}.
8657 Set mode of operation.
8659 Can be one of the following:
8663 Use frame flags, both fields.
8665 Use frame flags, single field.
8669 Use bottom field only.
8671 Use both fields, top first.
8673 Use both fields, bottom first.
8677 Set which planes to process, by default filter process all frames.
8680 Set size of local neighborhood around each pixel, used by the predictor neural
8683 Can be one of the following:
8696 Set the number of neurons in predicctor neural network.
8697 Can be one of the following:
8708 Controls the number of different neural network predictions that are blended
8709 together to compute the final output value. Can be @code{fast}, default or
8713 Set which set of weights to use in the predictor.
8714 Can be one of the following:
8718 weights trained to minimize absolute error
8720 weights trained to minimize squared error
8724 Controls whether or not the prescreener neural network is used to decide
8725 which pixels should be processed by the predictor neural network and which
8726 can be handled by simple cubic interpolation.
8727 The prescreener is trained to know whether cubic interpolation will be
8728 sufficient for a pixel or whether it should be predicted by the predictor nn.
8729 The computational complexity of the prescreener nn is much less than that of
8730 the predictor nn. Since most pixels can be handled by cubic interpolation,
8731 using the prescreener generally results in much faster processing.
8732 The prescreener is pretty accurate, so the difference between using it and not
8733 using it is almost always unnoticeable.
8735 Can be one of the following:
8743 Default is @code{new}.
8746 Set various debugging flags.
8751 Force libavfilter not to use any of the specified pixel formats for the
8752 input to the next filter.
8754 It accepts the following parameters:
8758 A '|'-separated list of pixel format names, such as
8759 apix_fmts=yuv420p|monow|rgb24".
8763 @subsection Examples
8767 Force libavfilter to use a format different from @var{yuv420p} for the
8768 input to the vflip filter:
8770 noformat=pix_fmts=yuv420p,vflip
8774 Convert the input video to any of the formats not contained in the list:
8776 noformat=yuv420p|yuv444p|yuv410p
8782 Add noise on video input frame.
8784 The filter accepts the following options:
8792 Set noise seed for specific pixel component or all pixel components in case
8793 of @var{all_seed}. Default value is @code{123457}.
8795 @item all_strength, alls
8796 @item c0_strength, c0s
8797 @item c1_strength, c1s
8798 @item c2_strength, c2s
8799 @item c3_strength, c3s
8800 Set noise strength for specific pixel component or all pixel components in case
8801 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
8803 @item all_flags, allf
8808 Set pixel component flags or set flags for all components if @var{all_flags}.
8809 Available values for component flags are:
8812 averaged temporal noise (smoother)
8814 mix random noise with a (semi)regular pattern
8816 temporal noise (noise pattern changes between frames)
8818 uniform noise (gaussian otherwise)
8822 @subsection Examples
8824 Add temporal and uniform noise to input video:
8826 noise=alls=20:allf=t+u
8831 Pass the video source unchanged to the output.
8834 Optical Character Recognition
8836 This filter uses Tesseract for optical character recognition.
8838 It accepts the following options:
8842 Set datapath to tesseract data. Default is to use whatever was
8843 set at installation.
8846 Set language, default is "eng".
8849 Set character whitelist.
8852 Set character blacklist.
8855 The filter exports recognized text as the frame metadata @code{lavfi.ocr.text}.
8859 Apply a video transform using libopencv.
8861 To enable this filter, install the libopencv library and headers and
8862 configure FFmpeg with @code{--enable-libopencv}.
8864 It accepts the following parameters:
8869 The name of the libopencv filter to apply.
8872 The parameters to pass to the libopencv filter. If not specified, the default
8877 Refer to the official libopencv documentation for more precise
8879 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
8881 Several libopencv filters are supported; see the following subsections.
8886 Dilate an image by using a specific structuring element.
8887 It corresponds to the libopencv function @code{cvDilate}.
8889 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
8891 @var{struct_el} represents a structuring element, and has the syntax:
8892 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
8894 @var{cols} and @var{rows} represent the number of columns and rows of
8895 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
8896 point, and @var{shape} the shape for the structuring element. @var{shape}
8897 must be "rect", "cross", "ellipse", or "custom".
8899 If the value for @var{shape} is "custom", it must be followed by a
8900 string of the form "=@var{filename}". The file with name
8901 @var{filename} is assumed to represent a binary image, with each
8902 printable character corresponding to a bright pixel. When a custom
8903 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
8904 or columns and rows of the read file are assumed instead.
8906 The default value for @var{struct_el} is "3x3+0x0/rect".
8908 @var{nb_iterations} specifies the number of times the transform is
8909 applied to the image, and defaults to 1.
8913 # Use the default values
8916 # Dilate using a structuring element with a 5x5 cross, iterating two times
8917 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
8919 # Read the shape from the file diamond.shape, iterating two times.
8920 # The file diamond.shape may contain a pattern of characters like this
8926 # The specified columns and rows are ignored
8927 # but the anchor point coordinates are not
8928 ocv=dilate:0x0+2x2/custom=diamond.shape|2
8933 Erode an image by using a specific structuring element.
8934 It corresponds to the libopencv function @code{cvErode}.
8936 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
8937 with the same syntax and semantics as the @ref{dilate} filter.
8941 Smooth the input video.
8943 The filter takes the following parameters:
8944 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
8946 @var{type} is the type of smooth filter to apply, and must be one of
8947 the following values: "blur", "blur_no_scale", "median", "gaussian",
8948 or "bilateral". The default value is "gaussian".
8950 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
8951 depend on the smooth type. @var{param1} and
8952 @var{param2} accept integer positive values or 0. @var{param3} and
8953 @var{param4} accept floating point values.
8955 The default value for @var{param1} is 3. The default value for the
8956 other parameters is 0.
8958 These parameters correspond to the parameters assigned to the
8959 libopencv function @code{cvSmooth}.
8964 Overlay one video on top of another.
8966 It takes two inputs and has one output. The first input is the "main"
8967 video on which the second input is overlaid.
8969 It accepts the following parameters:
8971 A description of the accepted options follows.
8976 Set the expression for the x and y coordinates of the overlaid video
8977 on the main video. Default value is "0" for both expressions. In case
8978 the expression is invalid, it is set to a huge value (meaning that the
8979 overlay will not be displayed within the output visible area).
8982 The action to take when EOF is encountered on the secondary input; it accepts
8983 one of the following values:
8987 Repeat the last frame (the default).
8991 Pass the main input through.
8995 Set when the expressions for @option{x}, and @option{y} are evaluated.
8997 It accepts the following values:
9000 only evaluate expressions once during the filter initialization or
9001 when a command is processed
9004 evaluate expressions for each incoming frame
9007 Default value is @samp{frame}.
9010 If set to 1, force the output to terminate when the shortest input
9011 terminates. Default value is 0.
9014 Set the format for the output video.
9016 It accepts the following values:
9031 Default value is @samp{yuv420}.
9033 @item rgb @emph{(deprecated)}
9034 If set to 1, force the filter to accept inputs in the RGB
9035 color space. Default value is 0. This option is deprecated, use
9036 @option{format} instead.
9039 If set to 1, force the filter to draw the last overlay frame over the
9040 main input until the end of the stream. A value of 0 disables this
9041 behavior. Default value is 1.
9044 The @option{x}, and @option{y} expressions can contain the following
9050 The main input width and height.
9054 The overlay input width and height.
9058 The computed values for @var{x} and @var{y}. They are evaluated for
9063 horizontal and vertical chroma subsample values of the output
9064 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
9068 the number of input frame, starting from 0
9071 the position in the file of the input frame, NAN if unknown
9074 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
9078 Note that the @var{n}, @var{pos}, @var{t} variables are available only
9079 when evaluation is done @emph{per frame}, and will evaluate to NAN
9080 when @option{eval} is set to @samp{init}.
9082 Be aware that frames are taken from each input video in timestamp
9083 order, hence, if their initial timestamps differ, it is a good idea
9084 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
9085 have them begin in the same zero timestamp, as the example for
9086 the @var{movie} filter does.
9088 You can chain together more overlays but you should test the
9089 efficiency of such approach.
9091 @subsection Commands
9093 This filter supports the following commands:
9097 Modify the x and y of the overlay input.
9098 The command accepts the same syntax of the corresponding option.
9100 If the specified expression is not valid, it is kept at its current
9104 @subsection Examples
9108 Draw the overlay at 10 pixels from the bottom right corner of the main
9111 overlay=main_w-overlay_w-10:main_h-overlay_h-10
9114 Using named options the example above becomes:
9116 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
9120 Insert a transparent PNG logo in the bottom left corner of the input,
9121 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
9123 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
9127 Insert 2 different transparent PNG logos (second logo on bottom
9128 right corner) using the @command{ffmpeg} tool:
9130 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
9134 Add a transparent color layer on top of the main video; @code{WxH}
9135 must specify the size of the main input to the overlay filter:
9137 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
9141 Play an original video and a filtered version (here with the deshake
9142 filter) side by side using the @command{ffplay} tool:
9144 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
9147 The above command is the same as:
9149 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
9153 Make a sliding overlay appearing from the left to the right top part of the
9154 screen starting since time 2:
9156 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
9160 Compose output by putting two input videos side to side:
9162 ffmpeg -i left.avi -i right.avi -filter_complex "
9163 nullsrc=size=200x100 [background];
9164 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
9165 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
9166 [background][left] overlay=shortest=1 [background+left];
9167 [background+left][right] overlay=shortest=1:x=100 [left+right]
9172 Mask 10-20 seconds of a video by applying the delogo filter to a section
9174 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
9175 -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]'
9180 Chain several overlays in cascade:
9182 nullsrc=s=200x200 [bg];
9183 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
9184 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
9185 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
9186 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
9187 [in3] null, [mid2] overlay=100:100 [out0]
9194 Apply Overcomplete Wavelet denoiser.
9196 The filter accepts the following options:
9202 Larger depth values will denoise lower frequency components more, but
9203 slow down filtering.
9205 Must be an int in the range 8-16, default is @code{8}.
9207 @item luma_strength, ls
9210 Must be a double value in the range 0-1000, default is @code{1.0}.
9212 @item chroma_strength, cs
9213 Set chroma strength.
9215 Must be a double value in the range 0-1000, default is @code{1.0}.
9221 Add paddings to the input image, and place the original input at the
9222 provided @var{x}, @var{y} coordinates.
9224 It accepts the following parameters:
9229 Specify an expression for the size of the output image with the
9230 paddings added. If the value for @var{width} or @var{height} is 0, the
9231 corresponding input size is used for the output.
9233 The @var{width} expression can reference the value set by the
9234 @var{height} expression, and vice versa.
9236 The default value of @var{width} and @var{height} is 0.
9240 Specify the offsets to place the input image at within the padded area,
9241 with respect to the top/left border of the output image.
9243 The @var{x} expression can reference the value set by the @var{y}
9244 expression, and vice versa.
9246 The default value of @var{x} and @var{y} is 0.
9249 Specify the color of the padded area. For the syntax of this option,
9250 check the "Color" section in the ffmpeg-utils manual.
9252 The default value of @var{color} is "black".
9255 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
9256 options are expressions containing the following constants:
9261 The input video width and height.
9265 These are the same as @var{in_w} and @var{in_h}.
9269 The output width and height (the size of the padded area), as
9270 specified by the @var{width} and @var{height} expressions.
9274 These are the same as @var{out_w} and @var{out_h}.
9278 The x and y offsets as specified by the @var{x} and @var{y}
9279 expressions, or NAN if not yet specified.
9282 same as @var{iw} / @var{ih}
9285 input sample aspect ratio
9288 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
9292 The horizontal and vertical chroma subsample values. For example for the
9293 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9296 @subsection Examples
9300 Add paddings with the color "violet" to the input video. The output video
9301 size is 640x480, and the top-left corner of the input video is placed at
9304 pad=640:480:0:40:violet
9307 The example above is equivalent to the following command:
9309 pad=width=640:height=480:x=0:y=40:color=violet
9313 Pad the input to get an output with dimensions increased by 3/2,
9314 and put the input video at the center of the padded area:
9316 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
9320 Pad the input to get a squared output with size equal to the maximum
9321 value between the input width and height, and put the input video at
9322 the center of the padded area:
9324 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
9328 Pad the input to get a final w/h ratio of 16:9:
9330 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
9334 In case of anamorphic video, in order to set the output display aspect
9335 correctly, it is necessary to use @var{sar} in the expression,
9336 according to the relation:
9338 (ih * X / ih) * sar = output_dar
9339 X = output_dar / sar
9342 Thus the previous example needs to be modified to:
9344 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
9348 Double the output size and put the input video in the bottom-right
9349 corner of the output padded area:
9351 pad="2*iw:2*ih:ow-iw:oh-ih"
9358 Generate one palette for a whole video stream.
9360 It accepts the following options:
9364 Set the maximum number of colors to quantize in the palette.
9365 Note: the palette will still contain 256 colors; the unused palette entries
9368 @item reserve_transparent
9369 Create a palette of 255 colors maximum and reserve the last one for
9370 transparency. Reserving the transparency color is useful for GIF optimization.
9371 If not set, the maximum of colors in the palette will be 256. You probably want
9372 to disable this option for a standalone image.
9376 Set statistics mode.
9378 It accepts the following values:
9381 Compute full frame histograms.
9383 Compute histograms only for the part that differs from previous frame. This
9384 might be relevant to give more importance to the moving part of your input if
9385 the background is static.
9388 Default value is @var{full}.
9391 The filter also exports the frame metadata @code{lavfi.color_quant_ratio}
9392 (@code{nb_color_in / nb_color_out}) which you can use to evaluate the degree of
9393 color quantization of the palette. This information is also visible at
9394 @var{info} logging level.
9396 @subsection Examples
9400 Generate a representative palette of a given video using @command{ffmpeg}:
9402 ffmpeg -i input.mkv -vf palettegen palette.png
9408 Use a palette to downsample an input video stream.
9410 The filter takes two inputs: one video stream and a palette. The palette must
9411 be a 256 pixels image.
9413 It accepts the following options:
9417 Select dithering mode. Available algorithms are:
9420 Ordered 8x8 bayer dithering (deterministic)
9422 Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
9423 Note: this dithering is sometimes considered "wrong" and is included as a
9425 @item floyd_steinberg
9426 Floyd and Steingberg dithering (error diffusion)
9428 Frankie Sierra dithering v2 (error diffusion)
9430 Frankie Sierra dithering v2 "Lite" (error diffusion)
9433 Default is @var{sierra2_4a}.
9436 When @var{bayer} dithering is selected, this option defines the scale of the
9437 pattern (how much the crosshatch pattern is visible). A low value means more
9438 visible pattern for less banding, and higher value means less visible pattern
9439 at the cost of more banding.
9441 The option must be an integer value in the range [0,5]. Default is @var{2}.
9444 If set, define the zone to process
9448 Only the changing rectangle will be reprocessed. This is similar to GIF
9449 cropping/offsetting compression mechanism. This option can be useful for speed
9450 if only a part of the image is changing, and has use cases such as limiting the
9451 scope of the error diffusal @option{dither} to the rectangle that bounds the
9452 moving scene (it leads to more deterministic output if the scene doesn't change
9453 much, and as a result less moving noise and better GIF compression).
9456 Default is @var{none}.
9459 @subsection Examples
9463 Use a palette (generated for example with @ref{palettegen}) to encode a GIF
9464 using @command{ffmpeg}:
9466 ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
9470 @section perspective
9472 Correct perspective of video not recorded perpendicular to the screen.
9474 A description of the accepted parameters follows.
9485 Set coordinates expression for top left, top right, bottom left and bottom right corners.
9486 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
9487 If the @code{sense} option is set to @code{source}, then the specified points will be sent
9488 to the corners of the destination. If the @code{sense} option is set to @code{destination},
9489 then the corners of the source will be sent to the specified coordinates.
9491 The expressions can use the following variables:
9496 the width and height of video frame.
9500 Set interpolation for perspective correction.
9502 It accepts the following values:
9508 Default value is @samp{linear}.
9511 Set interpretation of coordinate options.
9513 It accepts the following values:
9517 Send point in the source specified by the given coordinates to
9518 the corners of the destination.
9520 @item 1, destination
9522 Send the corners of the source to the point in the destination specified
9523 by the given coordinates.
9525 Default value is @samp{source}.
9531 Delay interlaced video by one field time so that the field order changes.
9533 The intended use is to fix PAL movies that have been captured with the
9534 opposite field order to the film-to-video transfer.
9536 A description of the accepted parameters follows.
9542 It accepts the following values:
9545 Capture field order top-first, transfer bottom-first.
9546 Filter will delay the bottom field.
9549 Capture field order bottom-first, transfer top-first.
9550 Filter will delay the top field.
9553 Capture and transfer with the same field order. This mode only exists
9554 for the documentation of the other options to refer to, but if you
9555 actually select it, the filter will faithfully do nothing.
9558 Capture field order determined automatically by field flags, transfer
9560 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
9561 basis using field flags. If no field information is available,
9562 then this works just like @samp{u}.
9565 Capture unknown or varying, transfer opposite.
9566 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
9567 analyzing the images and selecting the alternative that produces best
9568 match between the fields.
9571 Capture top-first, transfer unknown or varying.
9572 Filter selects among @samp{t} and @samp{p} using image analysis.
9575 Capture bottom-first, transfer unknown or varying.
9576 Filter selects among @samp{b} and @samp{p} using image analysis.
9579 Capture determined by field flags, transfer unknown or varying.
9580 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
9581 image analysis. If no field information is available, then this works just
9582 like @samp{U}. This is the default mode.
9585 Both capture and transfer unknown or varying.
9586 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
9590 @section pixdesctest
9592 Pixel format descriptor test filter, mainly useful for internal
9593 testing. The output video should be equal to the input video.
9597 format=monow, pixdesctest
9600 can be used to test the monowhite pixel format descriptor definition.
9604 Enable the specified chain of postprocessing subfilters using libpostproc. This
9605 library should be automatically selected with a GPL build (@code{--enable-gpl}).
9606 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
9607 Each subfilter and some options have a short and a long name that can be used
9608 interchangeably, i.e. dr/dering are the same.
9610 The filters accept the following options:
9614 Set postprocessing subfilters string.
9617 All subfilters share common options to determine their scope:
9621 Honor the quality commands for this subfilter.
9624 Do chrominance filtering, too (default).
9627 Do luminance filtering only (no chrominance).
9630 Do chrominance filtering only (no luminance).
9633 These options can be appended after the subfilter name, separated by a '|'.
9635 Available subfilters are:
9638 @item hb/hdeblock[|difference[|flatness]]
9639 Horizontal deblocking filter
9642 Difference factor where higher values mean more deblocking (default: @code{32}).
9644 Flatness threshold where lower values mean more deblocking (default: @code{39}).
9647 @item vb/vdeblock[|difference[|flatness]]
9648 Vertical deblocking filter
9651 Difference factor where higher values mean more deblocking (default: @code{32}).
9653 Flatness threshold where lower values mean more deblocking (default: @code{39}).
9656 @item ha/hadeblock[|difference[|flatness]]
9657 Accurate horizontal deblocking filter
9660 Difference factor where higher values mean more deblocking (default: @code{32}).
9662 Flatness threshold where lower values mean more deblocking (default: @code{39}).
9665 @item va/vadeblock[|difference[|flatness]]
9666 Accurate vertical deblocking filter
9669 Difference factor where higher values mean more deblocking (default: @code{32}).
9671 Flatness threshold where lower values mean more deblocking (default: @code{39}).
9675 The horizontal and vertical deblocking filters share the difference and
9676 flatness values so you cannot set different horizontal and vertical
9681 Experimental horizontal deblocking filter
9684 Experimental vertical deblocking filter
9689 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
9692 larger -> stronger filtering
9694 larger -> stronger filtering
9696 larger -> stronger filtering
9699 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
9702 Stretch luminance to @code{0-255}.
9705 @item lb/linblenddeint
9706 Linear blend deinterlacing filter that deinterlaces the given block by
9707 filtering all lines with a @code{(1 2 1)} filter.
9709 @item li/linipoldeint
9710 Linear interpolating deinterlacing filter that deinterlaces the given block by
9711 linearly interpolating every second line.
9713 @item ci/cubicipoldeint
9714 Cubic interpolating deinterlacing filter deinterlaces the given block by
9715 cubically interpolating every second line.
9717 @item md/mediandeint
9718 Median deinterlacing filter that deinterlaces the given block by applying a
9719 median filter to every second line.
9721 @item fd/ffmpegdeint
9722 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
9723 second line with a @code{(-1 4 2 4 -1)} filter.
9726 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
9727 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
9729 @item fq/forceQuant[|quantizer]
9730 Overrides the quantizer table from the input with the constant quantizer you
9738 Default pp filter combination (@code{hb|a,vb|a,dr|a})
9741 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
9744 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
9747 @subsection Examples
9751 Apply horizontal and vertical deblocking, deringing and automatic
9752 brightness/contrast:
9758 Apply default filters without brightness/contrast correction:
9764 Apply default filters and temporal denoiser:
9766 pp=default/tmpnoise|1|2|3
9770 Apply deblocking on luminance only, and switch vertical deblocking on or off
9771 automatically depending on available CPU time:
9778 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
9779 similar to spp = 6 with 7 point DCT, where only the center sample is
9782 The filter accepts the following options:
9786 Force a constant quantization parameter. It accepts an integer in range
9787 0 to 63. If not set, the filter will use the QP from the video stream
9791 Set thresholding mode. Available modes are:
9795 Set hard thresholding.
9797 Set soft thresholding (better de-ringing effect, but likely blurrier).
9799 Set medium thresholding (good results, default).
9805 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
9806 Ratio) between two input videos.
9808 This filter takes in input two input videos, the first input is
9809 considered the "main" source and is passed unchanged to the
9810 output. The second input is used as a "reference" video for computing
9813 Both video inputs must have the same resolution and pixel format for
9814 this filter to work correctly. Also it assumes that both inputs
9815 have the same number of frames, which are compared one by one.
9817 The obtained average PSNR is printed through the logging system.
9819 The filter stores the accumulated MSE (mean squared error) of each
9820 frame, and at the end of the processing it is averaged across all frames
9821 equally, and the following formula is applied to obtain the PSNR:
9824 PSNR = 10*log10(MAX^2/MSE)
9827 Where MAX is the average of the maximum values of each component of the
9830 The description of the accepted parameters follows.
9834 If specified the filter will use the named file to save the PSNR of
9835 each individual frame. When filename equals "-" the data is sent to
9839 The file printed if @var{stats_file} is selected, contains a sequence of
9840 key/value pairs of the form @var{key}:@var{value} for each compared
9843 A description of each shown parameter follows:
9847 sequential number of the input frame, starting from 1
9850 Mean Square Error pixel-by-pixel average difference of the compared
9851 frames, averaged over all the image components.
9853 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
9854 Mean Square Error pixel-by-pixel average difference of the compared
9855 frames for the component specified by the suffix.
9857 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
9858 Peak Signal to Noise ratio of the compared frames for the component
9859 specified by the suffix.
9864 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
9865 [main][ref] psnr="stats_file=stats.log" [out]
9868 On this example the input file being processed is compared with the
9869 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
9870 is stored in @file{stats.log}.
9875 Pulldown reversal (inverse telecine) filter, capable of handling mixed
9876 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
9879 The pullup filter is designed to take advantage of future context in making
9880 its decisions. This filter is stateless in the sense that it does not lock
9881 onto a pattern to follow, but it instead looks forward to the following
9882 fields in order to identify matches and rebuild progressive frames.
9884 To produce content with an even framerate, insert the fps filter after
9885 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
9886 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
9888 The filter accepts the following options:
9895 These options set the amount of "junk" to ignore at the left, right, top, and
9896 bottom of the image, respectively. Left and right are in units of 8 pixels,
9897 while top and bottom are in units of 2 lines.
9898 The default is 8 pixels on each side.
9901 Set the strict breaks. Setting this option to 1 will reduce the chances of
9902 filter generating an occasional mismatched frame, but it may also cause an
9903 excessive number of frames to be dropped during high motion sequences.
9904 Conversely, setting it to -1 will make filter match fields more easily.
9905 This may help processing of video where there is slight blurring between
9906 the fields, but may also cause there to be interlaced frames in the output.
9907 Default value is @code{0}.
9910 Set the metric plane to use. It accepts the following values:
9916 Use chroma blue plane.
9919 Use chroma red plane.
9922 This option may be set to use chroma plane instead of the default luma plane
9923 for doing filter's computations. This may improve accuracy on very clean
9924 source material, but more likely will decrease accuracy, especially if there
9925 is chroma noise (rainbow effect) or any grayscale video.
9926 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
9927 load and make pullup usable in realtime on slow machines.
9930 For best results (without duplicated frames in the output file) it is
9931 necessary to change the output frame rate. For example, to inverse
9932 telecine NTSC input:
9934 ffmpeg -i input -vf pullup -r 24000/1001 ...
9939 Change video quantization parameters (QP).
9941 The filter accepts the following option:
9945 Set expression for quantization parameter.
9948 The expression is evaluated through the eval API and can contain, among others,
9949 the following constants:
9953 1 if index is not 129, 0 otherwise.
9956 Sequentional index starting from -129 to 128.
9959 @subsection Examples
9971 Flush video frames from internal cache of frames into a random order.
9972 No frame is discarded.
9973 Inspired by @ref{frei0r} nervous filter.
9977 Set size in number of frames of internal cache, in range from @code{2} to
9978 @code{512}. Default is @code{30}.
9981 Set seed for random number generator, must be an integer included between
9982 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
9983 less than @code{0}, the filter will try to use a good random seed on a
9987 @section removegrain
9989 The removegrain filter is a spatial denoiser for progressive video.
9993 Set mode for the first plane.
9996 Set mode for the second plane.
9999 Set mode for the third plane.
10002 Set mode for the fourth plane.
10005 Range of mode is from 0 to 24. Description of each mode follows:
10009 Leave input plane unchanged. Default.
10012 Clips the pixel with the minimum and maximum of the 8 neighbour pixels.
10015 Clips the pixel with the second minimum and maximum of the 8 neighbour pixels.
10018 Clips the pixel with the third minimum and maximum of the 8 neighbour pixels.
10021 Clips the pixel with the fourth minimum and maximum of the 8 neighbour pixels.
10022 This is equivalent to a median filter.
10025 Line-sensitive clipping giving the minimal change.
10028 Line-sensitive clipping, intermediate.
10031 Line-sensitive clipping, intermediate.
10034 Line-sensitive clipping, intermediate.
10037 Line-sensitive clipping on a line where the neighbours pixels are the closest.
10040 Replaces the target pixel with the closest neighbour.
10043 [1 2 1] horizontal and vertical kernel blur.
10049 Bob mode, interpolates top field from the line where the neighbours
10050 pixels are the closest.
10053 Bob mode, interpolates bottom field from the line where the neighbours
10054 pixels are the closest.
10057 Bob mode, interpolates top field. Same as 13 but with a more complicated
10058 interpolation formula.
10061 Bob mode, interpolates bottom field. Same as 14 but with a more complicated
10062 interpolation formula.
10065 Clips the pixel with the minimum and maximum of respectively the maximum and
10066 minimum of each pair of opposite neighbour pixels.
10069 Line-sensitive clipping using opposite neighbours whose greatest distance from
10070 the current pixel is minimal.
10073 Replaces the pixel with the average of its 8 neighbours.
10076 Averages the 9 pixels ([1 1 1] horizontal and vertical blur).
10079 Clips pixels using the averages of opposite neighbour.
10082 Same as mode 21 but simpler and faster.
10085 Small edge and halo removal, but reputed useless.
10091 @section removelogo
10093 Suppress a TV station logo, using an image file to determine which
10094 pixels comprise the logo. It works by filling in the pixels that
10095 comprise the logo with neighboring pixels.
10097 The filter accepts the following options:
10101 Set the filter bitmap file, which can be any image format supported by
10102 libavformat. The width and height of the image file must match those of the
10103 video stream being processed.
10106 Pixels in the provided bitmap image with a value of zero are not
10107 considered part of the logo, non-zero pixels are considered part of
10108 the logo. If you use white (255) for the logo and black (0) for the
10109 rest, you will be safe. For making the filter bitmap, it is
10110 recommended to take a screen capture of a black frame with the logo
10111 visible, and then using a threshold filter followed by the erode
10112 filter once or twice.
10114 If needed, little splotches can be fixed manually. Remember that if
10115 logo pixels are not covered, the filter quality will be much
10116 reduced. Marking too many pixels as part of the logo does not hurt as
10117 much, but it will increase the amount of blurring needed to cover over
10118 the image and will destroy more information than necessary, and extra
10119 pixels will slow things down on a large logo.
10121 @section repeatfields
10123 This filter uses the repeat_field flag from the Video ES headers and hard repeats
10124 fields based on its value.
10126 @section reverse, areverse
10130 Warning: This filter requires memory to buffer the entire clip, so trimming
10133 @subsection Examples
10137 Take the first 5 seconds of a clip, and reverse it.
10145 Rotate video by an arbitrary angle expressed in radians.
10147 The filter accepts the following options:
10149 A description of the optional parameters follows.
10152 Set an expression for the angle by which to rotate the input video
10153 clockwise, expressed as a number of radians. A negative value will
10154 result in a counter-clockwise rotation. By default it is set to "0".
10156 This expression is evaluated for each frame.
10159 Set the output width expression, default value is "iw".
10160 This expression is evaluated just once during configuration.
10163 Set the output height expression, default value is "ih".
10164 This expression is evaluated just once during configuration.
10167 Enable bilinear interpolation if set to 1, a value of 0 disables
10168 it. Default value is 1.
10171 Set the color used to fill the output area not covered by the rotated
10172 image. For the general syntax of this option, check the "Color" section in the
10173 ffmpeg-utils manual. If the special value "none" is selected then no
10174 background is printed (useful for example if the background is never shown).
10176 Default value is "black".
10179 The expressions for the angle and the output size can contain the
10180 following constants and functions:
10184 sequential number of the input frame, starting from 0. It is always NAN
10185 before the first frame is filtered.
10188 time in seconds of the input frame, it is set to 0 when the filter is
10189 configured. It is always NAN before the first frame is filtered.
10193 horizontal and vertical chroma subsample values. For example for the
10194 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
10198 the input video width and height
10202 the output width and height, that is the size of the padded area as
10203 specified by the @var{width} and @var{height} expressions
10207 the minimal width/height required for completely containing the input
10208 video rotated by @var{a} radians.
10210 These are only available when computing the @option{out_w} and
10211 @option{out_h} expressions.
10214 @subsection Examples
10218 Rotate the input by PI/6 radians clockwise:
10224 Rotate the input by PI/6 radians counter-clockwise:
10230 Rotate the input by 45 degrees clockwise:
10236 Apply a constant rotation with period T, starting from an angle of PI/3:
10238 rotate=PI/3+2*PI*t/T
10242 Make the input video rotation oscillating with a period of T
10243 seconds and an amplitude of A radians:
10245 rotate=A*sin(2*PI/T*t)
10249 Rotate the video, output size is chosen so that the whole rotating
10250 input video is always completely contained in the output:
10252 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
10256 Rotate the video, reduce the output size so that no background is ever
10259 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
10263 @subsection Commands
10265 The filter supports the following commands:
10269 Set the angle expression.
10270 The command accepts the same syntax of the corresponding option.
10272 If the specified expression is not valid, it is kept at its current
10278 Apply Shape Adaptive Blur.
10280 The filter accepts the following options:
10283 @item luma_radius, lr
10284 Set luma blur filter strength, must be a value in range 0.1-4.0, default
10285 value is 1.0. A greater value will result in a more blurred image, and
10286 in slower processing.
10288 @item luma_pre_filter_radius, lpfr
10289 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
10292 @item luma_strength, ls
10293 Set luma maximum difference between pixels to still be considered, must
10294 be a value in the 0.1-100.0 range, default value is 1.0.
10296 @item chroma_radius, cr
10297 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
10298 greater value will result in a more blurred image, and in slower
10301 @item chroma_pre_filter_radius, cpfr
10302 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
10304 @item chroma_strength, cs
10305 Set chroma maximum difference between pixels to still be considered,
10306 must be a value in the 0.1-100.0 range.
10309 Each chroma option value, if not explicitly specified, is set to the
10310 corresponding luma option value.
10315 Scale (resize) the input video, using the libswscale library.
10317 The scale filter forces the output display aspect ratio to be the same
10318 of the input, by changing the output sample aspect ratio.
10320 If the input image format is different from the format requested by
10321 the next filter, the scale filter will convert the input to the
10324 @subsection Options
10325 The filter accepts the following options, or any of the options
10326 supported by the libswscale scaler.
10328 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
10329 the complete list of scaler options.
10334 Set the output video dimension expression. Default value is the input
10337 If the value is 0, the input width is used for the output.
10339 If one of the values is -1, the scale filter will use a value that
10340 maintains the aspect ratio of the input image, calculated from the
10341 other specified dimension. If both of them are -1, the input size is
10344 If one of the values is -n with n > 1, the scale filter will also use a value
10345 that maintains the aspect ratio of the input image, calculated from the other
10346 specified dimension. After that it will, however, make sure that the calculated
10347 dimension is divisible by n and adjust the value if necessary.
10349 See below for the list of accepted constants for use in the dimension
10353 Specify when to evaluate @var{width} and @var{height} expression. It accepts the following values:
10357 Only evaluate expressions once during the filter initialization or when a command is processed.
10360 Evaluate expressions for each incoming frame.
10364 Default value is @samp{init}.
10368 Set the interlacing mode. It accepts the following values:
10372 Force interlaced aware scaling.
10375 Do not apply interlaced scaling.
10378 Select interlaced aware scaling depending on whether the source frames
10379 are flagged as interlaced or not.
10382 Default value is @samp{0}.
10385 Set libswscale scaling flags. See
10386 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
10387 complete list of values. If not explicitly specified the filter applies
10391 @item param0, param1
10392 Set libswscale input parameters for scaling algorithms that need them. See
10393 @ref{sws_params,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
10394 complete documentation. If not explicitly specified the filter applies
10400 Set the video size. For the syntax of this option, check the
10401 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10403 @item in_color_matrix
10404 @item out_color_matrix
10405 Set in/output YCbCr color space type.
10407 This allows the autodetected value to be overridden as well as allows forcing
10408 a specific value used for the output and encoder.
10410 If not specified, the color space type depends on the pixel format.
10416 Choose automatically.
10419 Format conforming to International Telecommunication Union (ITU)
10420 Recommendation BT.709.
10423 Set color space conforming to the United States Federal Communications
10424 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
10427 Set color space conforming to:
10431 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
10434 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
10437 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
10442 Set color space conforming to SMPTE ST 240:1999.
10447 Set in/output YCbCr sample range.
10449 This allows the autodetected value to be overridden as well as allows forcing
10450 a specific value used for the output and encoder. If not specified, the
10451 range depends on the pixel format. Possible values:
10455 Choose automatically.
10458 Set full range (0-255 in case of 8-bit luma).
10461 Set "MPEG" range (16-235 in case of 8-bit luma).
10464 @item force_original_aspect_ratio
10465 Enable decreasing or increasing output video width or height if necessary to
10466 keep the original aspect ratio. Possible values:
10470 Scale the video as specified and disable this feature.
10473 The output video dimensions will automatically be decreased if needed.
10476 The output video dimensions will automatically be increased if needed.
10480 One useful instance of this option is that when you know a specific device's
10481 maximum allowed resolution, you can use this to limit the output video to
10482 that, while retaining the aspect ratio. For example, device A allows
10483 1280x720 playback, and your video is 1920x800. Using this option (set it to
10484 decrease) and specifying 1280x720 to the command line makes the output
10487 Please note that this is a different thing than specifying -1 for @option{w}
10488 or @option{h}, you still need to specify the output resolution for this option
10493 The values of the @option{w} and @option{h} options are expressions
10494 containing the following constants:
10499 The input width and height
10503 These are the same as @var{in_w} and @var{in_h}.
10507 The output (scaled) width and height
10511 These are the same as @var{out_w} and @var{out_h}
10514 The same as @var{iw} / @var{ih}
10517 input sample aspect ratio
10520 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
10524 horizontal and vertical input chroma subsample values. For example for the
10525 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
10529 horizontal and vertical output chroma subsample values. For example for the
10530 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
10533 @subsection Examples
10537 Scale the input video to a size of 200x100
10542 This is equivalent to:
10553 Specify a size abbreviation for the output size:
10558 which can also be written as:
10564 Scale the input to 2x:
10566 scale=w=2*iw:h=2*ih
10570 The above is the same as:
10572 scale=2*in_w:2*in_h
10576 Scale the input to 2x with forced interlaced scaling:
10578 scale=2*iw:2*ih:interl=1
10582 Scale the input to half size:
10584 scale=w=iw/2:h=ih/2
10588 Increase the width, and set the height to the same size:
10594 Seek Greek harmony:
10601 Increase the height, and set the width to 3/2 of the height:
10603 scale=w=3/2*oh:h=3/5*ih
10607 Increase the size, making the size a multiple of the chroma
10610 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
10614 Increase the width to a maximum of 500 pixels,
10615 keeping the same aspect ratio as the input:
10617 scale=w='min(500\, iw*3/2):h=-1'
10621 @subsection Commands
10623 This filter supports the following commands:
10627 Set the output video dimension expression.
10628 The command accepts the same syntax of the corresponding option.
10630 If the specified expression is not valid, it is kept at its current
10636 Scale (resize) the input video, based on a reference video.
10638 See the scale filter for available options, scale2ref supports the same but
10639 uses the reference video instead of the main input as basis.
10641 @subsection Examples
10645 Scale a subtitle stream to match the main video in size before overlaying
10647 'scale2ref[b][a];[a][b]overlay'
10651 @section selectivecolor
10653 Adjust cyan, magenta, yellow and black (CMYK) to certain ranges of colors (such
10654 as "reds", "yellows", "greens", "cyans", ...). The adjustment range is defined
10655 by the "purity" of the color (that is, how saturated it already is).
10657 This filter is similar to the Adobe Photoshop Selective Color tool.
10659 The filter accepts the following options:
10662 @item correction_method
10663 Select color correction method.
10665 Available values are:
10668 Specified adjustments are applied "as-is" (added/subtracted to original pixel
10671 Specified adjustments are relative to the original component value.
10673 Default is @code{absolute}.
10675 Adjustments for red pixels (pixels where the red component is the maximum)
10677 Adjustments for yellow pixels (pixels where the blue component is the minimum)
10679 Adjustments for green pixels (pixels where the green component is the maximum)
10681 Adjustments for cyan pixels (pixels where the red component is the minimum)
10683 Adjustments for blue pixels (pixels where the blue component is the maximum)
10685 Adjustments for magenta pixels (pixels where the green component is the minimum)
10687 Adjustments for white pixels (pixels where all components are greater than 128)
10689 Adjustments for all pixels except pure black and pure white
10691 Adjustments for black pixels (pixels where all components are lesser than 128)
10693 Specify a Photoshop selective color file (@code{.asv}) to import the settings from.
10696 All the adjustment settings (@option{reds}, @option{yellows}, ...) accept up to
10697 4 space separated floating point adjustment values in the [-1,1] range,
10698 respectively to adjust the amount of cyan, magenta, yellow and black for the
10699 pixels of its range.
10701 @subsection Examples
10705 Increase cyan by 50% and reduce yellow by 33% in every green areas, and
10706 increase magenta by 27% in blue areas:
10708 selectivecolor=greens=.5 0 -.33 0:blues=0 .27
10712 Use a Photoshop selective color preset:
10714 selectivecolor=psfile=MySelectiveColorPresets/Misty.asv
10718 @section separatefields
10720 The @code{separatefields} takes a frame-based video input and splits
10721 each frame into its components fields, producing a new half height clip
10722 with twice the frame rate and twice the frame count.
10724 This filter use field-dominance information in frame to decide which
10725 of each pair of fields to place first in the output.
10726 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
10728 @section setdar, setsar
10730 The @code{setdar} filter sets the Display Aspect Ratio for the filter
10733 This is done by changing the specified Sample (aka Pixel) Aspect
10734 Ratio, according to the following equation:
10736 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
10739 Keep in mind that the @code{setdar} filter does not modify the pixel
10740 dimensions of the video frame. Also, the display aspect ratio set by
10741 this filter may be changed by later filters in the filterchain,
10742 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
10745 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
10746 the filter output video.
10748 Note that as a consequence of the application of this filter, the
10749 output display aspect ratio will change according to the equation
10752 Keep in mind that the sample aspect ratio set by the @code{setsar}
10753 filter may be changed by later filters in the filterchain, e.g. if
10754 another "setsar" or a "setdar" filter is applied.
10756 It accepts the following parameters:
10759 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
10760 Set the aspect ratio used by the filter.
10762 The parameter can be a floating point number string, an expression, or
10763 a string of the form @var{num}:@var{den}, where @var{num} and
10764 @var{den} are the numerator and denominator of the aspect ratio. If
10765 the parameter is not specified, it is assumed the value "0".
10766 In case the form "@var{num}:@var{den}" is used, the @code{:} character
10770 Set the maximum integer value to use for expressing numerator and
10771 denominator when reducing the expressed aspect ratio to a rational.
10772 Default value is @code{100}.
10776 The parameter @var{sar} is an expression containing
10777 the following constants:
10781 These are approximated values for the mathematical constants e
10782 (Euler's number), pi (Greek pi), and phi (the golden ratio).
10785 The input width and height.
10788 These are the same as @var{w} / @var{h}.
10791 The input sample aspect ratio.
10794 The input display aspect ratio. It is the same as
10795 (@var{w} / @var{h}) * @var{sar}.
10798 Horizontal and vertical chroma subsample values. For example, for the
10799 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
10802 @subsection Examples
10807 To change the display aspect ratio to 16:9, specify one of the following:
10815 To change the sample aspect ratio to 10:11, specify:
10821 To set a display aspect ratio of 16:9, and specify a maximum integer value of
10822 1000 in the aspect ratio reduction, use the command:
10824 setdar=ratio=16/9:max=1000
10832 Force field for the output video frame.
10834 The @code{setfield} filter marks the interlace type field for the
10835 output frames. It does not change the input frame, but only sets the
10836 corresponding property, which affects how the frame is treated by
10837 following filters (e.g. @code{fieldorder} or @code{yadif}).
10839 The filter accepts the following options:
10844 Available values are:
10848 Keep the same field property.
10851 Mark the frame as bottom-field-first.
10854 Mark the frame as top-field-first.
10857 Mark the frame as progressive.
10863 Show a line containing various information for each input video frame.
10864 The input video is not modified.
10866 The shown line contains a sequence of key/value pairs of the form
10867 @var{key}:@var{value}.
10869 The following values are shown in the output:
10873 The (sequential) number of the input frame, starting from 0.
10876 The Presentation TimeStamp of the input frame, expressed as a number of
10877 time base units. The time base unit depends on the filter input pad.
10880 The Presentation TimeStamp of the input frame, expressed as a number of
10884 The position of the frame in the input stream, or -1 if this information is
10885 unavailable and/or meaningless (for example in case of synthetic video).
10888 The pixel format name.
10891 The sample aspect ratio of the input frame, expressed in the form
10892 @var{num}/@var{den}.
10895 The size of the input frame. For the syntax of this option, check the
10896 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10899 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
10900 for bottom field first).
10903 This is 1 if the frame is a key frame, 0 otherwise.
10906 The picture type of the input frame ("I" for an I-frame, "P" for a
10907 P-frame, "B" for a B-frame, or "?" for an unknown type).
10908 Also refer to the documentation of the @code{AVPictureType} enum and of
10909 the @code{av_get_picture_type_char} function defined in
10910 @file{libavutil/avutil.h}.
10913 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
10915 @item plane_checksum
10916 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
10917 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
10920 @section showpalette
10922 Displays the 256 colors palette of each frame. This filter is only relevant for
10923 @var{pal8} pixel format frames.
10925 It accepts the following option:
10929 Set the size of the box used to represent one palette color entry. Default is
10930 @code{30} (for a @code{30x30} pixel box).
10933 @section shuffleframes
10935 Reorder and/or duplicate video frames.
10937 It accepts the following parameters:
10941 Set the destination indexes of input frames.
10942 This is space or '|' separated list of indexes that maps input frames to output
10943 frames. Number of indexes also sets maximal value that each index may have.
10946 The first frame has the index 0. The default is to keep the input unchanged.
10948 Swap second and third frame of every three frames of the input:
10950 ffmpeg -i INPUT -vf "shuffleframes=0 2 1" OUTPUT
10953 @section shuffleplanes
10955 Reorder and/or duplicate video planes.
10957 It accepts the following parameters:
10962 The index of the input plane to be used as the first output plane.
10965 The index of the input plane to be used as the second output plane.
10968 The index of the input plane to be used as the third output plane.
10971 The index of the input plane to be used as the fourth output plane.
10975 The first plane has the index 0. The default is to keep the input unchanged.
10977 Swap the second and third planes of the input:
10979 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
10982 @anchor{signalstats}
10983 @section signalstats
10984 Evaluate various visual metrics that assist in determining issues associated
10985 with the digitization of analog video media.
10987 By default the filter will log these metadata values:
10991 Display the minimal Y value contained within the input frame. Expressed in
10995 Display the Y value at the 10% percentile within the input frame. Expressed in
10999 Display the average Y value within the input frame. Expressed in range of
11003 Display the Y value at the 90% percentile within the input frame. Expressed in
11007 Display the maximum Y value contained within the input frame. Expressed in
11011 Display the minimal U value contained within the input frame. Expressed in
11015 Display the U value at the 10% percentile within the input frame. Expressed in
11019 Display the average U value within the input frame. Expressed in range of
11023 Display the U value at the 90% percentile within the input frame. Expressed in
11027 Display the maximum U value contained within the input frame. Expressed in
11031 Display the minimal V value contained within the input frame. Expressed in
11035 Display the V value at the 10% percentile within the input frame. Expressed in
11039 Display the average V value within the input frame. Expressed in range of
11043 Display the V value at the 90% percentile within the input frame. Expressed in
11047 Display the maximum V value contained within the input frame. Expressed in
11051 Display the minimal saturation value contained within the input frame.
11052 Expressed in range of [0-~181.02].
11055 Display the saturation value at the 10% percentile within the input frame.
11056 Expressed in range of [0-~181.02].
11059 Display the average saturation value within the input frame. Expressed in range
11063 Display the saturation value at the 90% percentile within the input frame.
11064 Expressed in range of [0-~181.02].
11067 Display the maximum saturation value contained within the input frame.
11068 Expressed in range of [0-~181.02].
11071 Display the median value for hue within the input frame. Expressed in range of
11075 Display the average value for hue within the input frame. Expressed in range of
11079 Display the average of sample value difference between all values of the Y
11080 plane in the current frame and corresponding values of the previous input frame.
11081 Expressed in range of [0-255].
11084 Display the average of sample value difference between all values of the U
11085 plane in the current frame and corresponding values of the previous input frame.
11086 Expressed in range of [0-255].
11089 Display the average of sample value difference between all values of the V
11090 plane in the current frame and corresponding values of the previous input frame.
11091 Expressed in range of [0-255].
11094 The filter accepts the following options:
11100 @option{stat} specify an additional form of image analysis.
11101 @option{out} output video with the specified type of pixel highlighted.
11103 Both options accept the following values:
11107 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
11108 unlike the neighboring pixels of the same field. Examples of temporal outliers
11109 include the results of video dropouts, head clogs, or tape tracking issues.
11112 Identify @var{vertical line repetition}. Vertical line repetition includes
11113 similar rows of pixels within a frame. In born-digital video vertical line
11114 repetition is common, but this pattern is uncommon in video digitized from an
11115 analog source. When it occurs in video that results from the digitization of an
11116 analog source it can indicate concealment from a dropout compensator.
11119 Identify pixels that fall outside of legal broadcast range.
11123 Set the highlight color for the @option{out} option. The default color is
11127 @subsection Examples
11131 Output data of various video metrics:
11133 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
11137 Output specific data about the minimum and maximum values of the Y plane per frame:
11139 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
11143 Playback video while highlighting pixels that are outside of broadcast range in red.
11145 ffplay example.mov -vf signalstats="out=brng:color=red"
11149 Playback video with signalstats metadata drawn over the frame.
11151 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
11154 The contents of signalstat_drawtext.txt used in the command are:
11157 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
11158 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
11159 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
11160 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
11168 Blur the input video without impacting the outlines.
11170 It accepts the following options:
11173 @item luma_radius, lr
11174 Set the luma radius. The option value must be a float number in
11175 the range [0.1,5.0] that specifies the variance of the gaussian filter
11176 used to blur the image (slower if larger). Default value is 1.0.
11178 @item luma_strength, ls
11179 Set the luma strength. The option value must be a float number
11180 in the range [-1.0,1.0] that configures the blurring. A value included
11181 in [0.0,1.0] will blur the image whereas a value included in
11182 [-1.0,0.0] will sharpen the image. Default value is 1.0.
11184 @item luma_threshold, lt
11185 Set the luma threshold used as a coefficient to determine
11186 whether a pixel should be blurred or not. The option value must be an
11187 integer in the range [-30,30]. A value of 0 will filter all the image,
11188 a value included in [0,30] will filter flat areas and a value included
11189 in [-30,0] will filter edges. Default value is 0.
11191 @item chroma_radius, cr
11192 Set the chroma radius. The option value must be a float number in
11193 the range [0.1,5.0] that specifies the variance of the gaussian filter
11194 used to blur the image (slower if larger). Default value is 1.0.
11196 @item chroma_strength, cs
11197 Set the chroma strength. The option value must be a float number
11198 in the range [-1.0,1.0] that configures the blurring. A value included
11199 in [0.0,1.0] will blur the image whereas a value included in
11200 [-1.0,0.0] will sharpen the image. Default value is 1.0.
11202 @item chroma_threshold, ct
11203 Set the chroma threshold used as a coefficient to determine
11204 whether a pixel should be blurred or not. The option value must be an
11205 integer in the range [-30,30]. A value of 0 will filter all the image,
11206 a value included in [0,30] will filter flat areas and a value included
11207 in [-30,0] will filter edges. Default value is 0.
11210 If a chroma option is not explicitly set, the corresponding luma value
11215 Obtain the SSIM (Structural SImilarity Metric) between two input videos.
11217 This filter takes in input two input videos, the first input is
11218 considered the "main" source and is passed unchanged to the
11219 output. The second input is used as a "reference" video for computing
11222 Both video inputs must have the same resolution and pixel format for
11223 this filter to work correctly. Also it assumes that both inputs
11224 have the same number of frames, which are compared one by one.
11226 The filter stores the calculated SSIM of each frame.
11228 The description of the accepted parameters follows.
11231 @item stats_file, f
11232 If specified the filter will use the named file to save the SSIM of
11233 each individual frame. When filename equals "-" the data is sent to
11237 The file printed if @var{stats_file} is selected, contains a sequence of
11238 key/value pairs of the form @var{key}:@var{value} for each compared
11241 A description of each shown parameter follows:
11245 sequential number of the input frame, starting from 1
11247 @item Y, U, V, R, G, B
11248 SSIM of the compared frames for the component specified by the suffix.
11251 SSIM of the compared frames for the whole frame.
11254 Same as above but in dB representation.
11259 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
11260 [main][ref] ssim="stats_file=stats.log" [out]
11263 On this example the input file being processed is compared with the
11264 reference file @file{ref_movie.mpg}. The SSIM of each individual frame
11265 is stored in @file{stats.log}.
11267 Another example with both psnr and ssim at same time:
11269 ffmpeg -i main.mpg -i ref.mpg -lavfi "ssim;[0:v][1:v]psnr" -f null -
11274 Convert between different stereoscopic image formats.
11276 The filters accept the following options:
11280 Set stereoscopic image format of input.
11282 Available values for input image formats are:
11285 side by side parallel (left eye left, right eye right)
11288 side by side crosseye (right eye left, left eye right)
11291 side by side parallel with half width resolution
11292 (left eye left, right eye right)
11295 side by side crosseye with half width resolution
11296 (right eye left, left eye right)
11299 above-below (left eye above, right eye below)
11302 above-below (right eye above, left eye below)
11305 above-below with half height resolution
11306 (left eye above, right eye below)
11309 above-below with half height resolution
11310 (right eye above, left eye below)
11313 alternating frames (left eye first, right eye second)
11316 alternating frames (right eye first, left eye second)
11319 interleaved rows (left eye has top row, right eye starts on next row)
11322 interleaved rows (right eye has top row, left eye starts on next row)
11325 interleaved columns, left eye first
11328 interleaved columns, right eye first
11330 Default value is @samp{sbsl}.
11334 Set stereoscopic image format of output.
11338 side by side parallel (left eye left, right eye right)
11341 side by side crosseye (right eye left, left eye right)
11344 side by side parallel with half width resolution
11345 (left eye left, right eye right)
11348 side by side crosseye with half width resolution
11349 (right eye left, left eye right)
11352 above-below (left eye above, right eye below)
11355 above-below (right eye above, left eye below)
11358 above-below with half height resolution
11359 (left eye above, right eye below)
11362 above-below with half height resolution
11363 (right eye above, left eye below)
11366 alternating frames (left eye first, right eye second)
11369 alternating frames (right eye first, left eye second)
11372 interleaved rows (left eye has top row, right eye starts on next row)
11375 interleaved rows (right eye has top row, left eye starts on next row)
11378 anaglyph red/blue gray
11379 (red filter on left eye, blue filter on right eye)
11382 anaglyph red/green gray
11383 (red filter on left eye, green filter on right eye)
11386 anaglyph red/cyan gray
11387 (red filter on left eye, cyan filter on right eye)
11390 anaglyph red/cyan half colored
11391 (red filter on left eye, cyan filter on right eye)
11394 anaglyph red/cyan color
11395 (red filter on left eye, cyan filter on right eye)
11398 anaglyph red/cyan color optimized with the least squares projection of dubois
11399 (red filter on left eye, cyan filter on right eye)
11402 anaglyph green/magenta gray
11403 (green filter on left eye, magenta filter on right eye)
11406 anaglyph green/magenta half colored
11407 (green filter on left eye, magenta filter on right eye)
11410 anaglyph green/magenta colored
11411 (green filter on left eye, magenta filter on right eye)
11414 anaglyph green/magenta color optimized with the least squares projection of dubois
11415 (green filter on left eye, magenta filter on right eye)
11418 anaglyph yellow/blue gray
11419 (yellow filter on left eye, blue filter on right eye)
11422 anaglyph yellow/blue half colored
11423 (yellow filter on left eye, blue filter on right eye)
11426 anaglyph yellow/blue colored
11427 (yellow filter on left eye, blue filter on right eye)
11430 anaglyph yellow/blue color optimized with the least squares projection of dubois
11431 (yellow filter on left eye, blue filter on right eye)
11434 mono output (left eye only)
11437 mono output (right eye only)
11440 checkerboard, left eye first
11443 checkerboard, right eye first
11446 interleaved columns, left eye first
11449 interleaved columns, right eye first
11452 Default value is @samp{arcd}.
11455 @subsection Examples
11459 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
11465 Convert input video from above below (left eye above, right eye below) to side by side crosseye.
11471 @section streamselect, astreamselect
11472 Select video or audio streams.
11474 The filter accepts the following options:
11478 Set number of inputs. Default is 2.
11481 Set input indexes to remap to outputs.
11484 @subsection Commands
11486 The @code{streamselect} and @code{astreamselect} filter supports the following
11491 Set input indexes to remap to outputs.
11494 @subsection Examples
11498 Select first 5 seconds 1st stream and rest of time 2nd stream:
11500 sendcmd='5.0 streamselect map 1',streamselect=inputs=2:map=0
11504 Same as above, but for audio:
11506 asendcmd='5.0 astreamselect map 1',astreamselect=inputs=2:map=0
11513 Apply a simple postprocessing filter that compresses and decompresses the image
11514 at several (or - in the case of @option{quality} level @code{6} - all) shifts
11515 and average the results.
11517 The filter accepts the following options:
11521 Set quality. This option defines the number of levels for averaging. It accepts
11522 an integer in the range 0-6. If set to @code{0}, the filter will have no
11523 effect. A value of @code{6} means the higher quality. For each increment of
11524 that value the speed drops by a factor of approximately 2. Default value is
11528 Force a constant quantization parameter. If not set, the filter will use the QP
11529 from the video stream (if available).
11532 Set thresholding mode. Available modes are:
11536 Set hard thresholding (default).
11538 Set soft thresholding (better de-ringing effect, but likely blurrier).
11541 @item use_bframe_qp
11542 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
11543 option may cause flicker since the B-Frames have often larger QP. Default is
11544 @code{0} (not enabled).
11550 Draw subtitles on top of input video using the libass library.
11552 To enable compilation of this filter you need to configure FFmpeg with
11553 @code{--enable-libass}. This filter also requires a build with libavcodec and
11554 libavformat to convert the passed subtitles file to ASS (Advanced Substation
11555 Alpha) subtitles format.
11557 The filter accepts the following options:
11561 Set the filename of the subtitle file to read. It must be specified.
11563 @item original_size
11564 Specify the size of the original video, the video for which the ASS file
11565 was composed. For the syntax of this option, check the
11566 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11567 Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
11568 correctly scale the fonts if the aspect ratio has been changed.
11571 Set a directory path containing fonts that can be used by the filter.
11572 These fonts will be used in addition to whatever the font provider uses.
11575 Set subtitles input character encoding. @code{subtitles} filter only. Only
11576 useful if not UTF-8.
11578 @item stream_index, si
11579 Set subtitles stream index. @code{subtitles} filter only.
11582 Override default style or script info parameters of the subtitles. It accepts a
11583 string containing ASS style format @code{KEY=VALUE} couples separated by ",".
11586 If the first key is not specified, it is assumed that the first value
11587 specifies the @option{filename}.
11589 For example, to render the file @file{sub.srt} on top of the input
11590 video, use the command:
11595 which is equivalent to:
11597 subtitles=filename=sub.srt
11600 To render the default subtitles stream from file @file{video.mkv}, use:
11602 subtitles=video.mkv
11605 To render the second subtitles stream from that file, use:
11607 subtitles=video.mkv:si=1
11610 To make the subtitles stream from @file{sub.srt} appear in transparent green
11611 @code{DejaVu Serif}, use:
11613 subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'
11616 @section super2xsai
11618 Scale the input by 2x and smooth using the Super2xSaI (Scale and
11619 Interpolate) pixel art scaling algorithm.
11621 Useful for enlarging pixel art images without reducing sharpness.
11625 Swap two rectangular objects in video.
11627 This filter accepts the following options:
11637 Set 1st rect x coordinate.
11640 Set 1st rect y coordinate.
11643 Set 2nd rect x coordinate.
11646 Set 2nd rect y coordinate.
11648 All expressions are evaluated once for each frame.
11651 The all options are expressions containing the following constants:
11656 The input width and height.
11659 same as @var{w} / @var{h}
11662 input sample aspect ratio
11665 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
11668 The number of the input frame, starting from 0.
11671 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
11674 the position in the file of the input frame, NAN if unknown
11682 Apply telecine process to the video.
11684 This filter accepts the following options:
11693 The default value is @code{top}.
11697 A string of numbers representing the pulldown pattern you wish to apply.
11698 The default value is @code{23}.
11702 Some typical patterns:
11707 24p: 2332 (preferred)
11714 24p: 222222222223 ("Euro pulldown")
11720 Select the most representative frame in a given sequence of consecutive frames.
11722 The filter accepts the following options:
11726 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
11727 will pick one of them, and then handle the next batch of @var{n} frames until
11728 the end. Default is @code{100}.
11731 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
11732 value will result in a higher memory usage, so a high value is not recommended.
11734 @subsection Examples
11738 Extract one picture each 50 frames:
11744 Complete example of a thumbnail creation with @command{ffmpeg}:
11746 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
11752 Tile several successive frames together.
11754 The filter accepts the following options:
11759 Set the grid size (i.e. the number of lines and columns). For the syntax of
11760 this option, check the
11761 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11764 Set the maximum number of frames to render in the given area. It must be less
11765 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
11766 the area will be used.
11769 Set the outer border margin in pixels.
11772 Set the inner border thickness (i.e. the number of pixels between frames). For
11773 more advanced padding options (such as having different values for the edges),
11774 refer to the pad video filter.
11777 Specify the color of the unused area. For the syntax of this option, check the
11778 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
11782 @subsection Examples
11786 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
11788 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
11790 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
11791 duplicating each output frame to accommodate the originally detected frame
11795 Display @code{5} pictures in an area of @code{3x2} frames,
11796 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
11797 mixed flat and named options:
11799 tile=3x2:nb_frames=5:padding=7:margin=2
11803 @section tinterlace
11805 Perform various types of temporal field interlacing.
11807 Frames are counted starting from 1, so the first input frame is
11810 The filter accepts the following options:
11815 Specify the mode of the interlacing. This option can also be specified
11816 as a value alone. See below for a list of values for this option.
11818 Available values are:
11822 Move odd frames into the upper field, even into the lower field,
11823 generating a double height frame at half frame rate.
11827 Frame 1 Frame 2 Frame 3 Frame 4
11829 11111 22222 33333 44444
11830 11111 22222 33333 44444
11831 11111 22222 33333 44444
11832 11111 22222 33333 44444
11846 Only output even frames, odd frames are dropped, generating a frame with
11847 unchanged height at half frame rate.
11852 Frame 1 Frame 2 Frame 3 Frame 4
11854 11111 22222 33333 44444
11855 11111 22222 33333 44444
11856 11111 22222 33333 44444
11857 11111 22222 33333 44444
11867 Only output odd frames, even frames are dropped, generating a frame with
11868 unchanged height at half frame rate.
11873 Frame 1 Frame 2 Frame 3 Frame 4
11875 11111 22222 33333 44444
11876 11111 22222 33333 44444
11877 11111 22222 33333 44444
11878 11111 22222 33333 44444
11888 Expand each frame to full height, but pad alternate lines with black,
11889 generating a frame with double height at the same input frame rate.
11894 Frame 1 Frame 2 Frame 3 Frame 4
11896 11111 22222 33333 44444
11897 11111 22222 33333 44444
11898 11111 22222 33333 44444
11899 11111 22222 33333 44444
11902 11111 ..... 33333 .....
11903 ..... 22222 ..... 44444
11904 11111 ..... 33333 .....
11905 ..... 22222 ..... 44444
11906 11111 ..... 33333 .....
11907 ..... 22222 ..... 44444
11908 11111 ..... 33333 .....
11909 ..... 22222 ..... 44444
11913 @item interleave_top, 4
11914 Interleave the upper field from odd frames with the lower field from
11915 even frames, generating a frame with unchanged height at half frame rate.
11920 Frame 1 Frame 2 Frame 3 Frame 4
11922 11111<- 22222 33333<- 44444
11923 11111 22222<- 33333 44444<-
11924 11111<- 22222 33333<- 44444
11925 11111 22222<- 33333 44444<-
11935 @item interleave_bottom, 5
11936 Interleave the lower field from odd frames with the upper field from
11937 even frames, generating a frame with unchanged height at half frame rate.
11942 Frame 1 Frame 2 Frame 3 Frame 4
11944 11111 22222<- 33333 44444<-
11945 11111<- 22222 33333<- 44444
11946 11111 22222<- 33333 44444<-
11947 11111<- 22222 33333<- 44444
11957 @item interlacex2, 6
11958 Double frame rate with unchanged height. Frames are inserted each
11959 containing the second temporal field from the previous input frame and
11960 the first temporal field from the next input frame. This mode relies on
11961 the top_field_first flag. Useful for interlaced video displays with no
11962 field synchronisation.
11967 Frame 1 Frame 2 Frame 3 Frame 4
11969 11111 22222 33333 44444
11970 11111 22222 33333 44444
11971 11111 22222 33333 44444
11972 11111 22222 33333 44444
11975 11111 22222 22222 33333 33333 44444 44444
11976 11111 11111 22222 22222 33333 33333 44444
11977 11111 22222 22222 33333 33333 44444 44444
11978 11111 11111 22222 22222 33333 33333 44444
11982 Move odd frames into the upper field, even into the lower field,
11983 generating a double height frame at same frame rate.
11987 Frame 1 Frame 2 Frame 3 Frame 4
11989 11111 22222 33333 44444
11990 11111 22222 33333 44444
11991 11111 22222 33333 44444
11992 11111 22222 33333 44444
11995 11111 33333 33333 55555
11996 22222 22222 44444 44444
11997 11111 33333 33333 55555
11998 22222 22222 44444 44444
11999 11111 33333 33333 55555
12000 22222 22222 44444 44444
12001 11111 33333 33333 55555
12002 22222 22222 44444 44444
12007 Numeric values are deprecated but are accepted for backward
12008 compatibility reasons.
12010 Default mode is @code{merge}.
12013 Specify flags influencing the filter process.
12015 Available value for @var{flags} is:
12018 @item low_pass_filter, vlfp
12019 Enable vertical low-pass filtering in the filter.
12020 Vertical low-pass filtering is required when creating an interlaced
12021 destination from a progressive source which contains high-frequency
12022 vertical detail. Filtering will reduce interlace 'twitter' and Moire
12025 Vertical low-pass filtering can only be enabled for @option{mode}
12026 @var{interleave_top} and @var{interleave_bottom}.
12033 Transpose rows with columns in the input video and optionally flip it.
12035 It accepts the following parameters:
12040 Specify the transposition direction.
12042 Can assume the following values:
12044 @item 0, 4, cclock_flip
12045 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
12053 Rotate by 90 degrees clockwise, that is:
12061 Rotate by 90 degrees counterclockwise, that is:
12068 @item 3, 7, clock_flip
12069 Rotate by 90 degrees clockwise and vertically flip, that is:
12077 For values between 4-7, the transposition is only done if the input
12078 video geometry is portrait and not landscape. These values are
12079 deprecated, the @code{passthrough} option should be used instead.
12081 Numerical values are deprecated, and should be dropped in favor of
12082 symbolic constants.
12085 Do not apply the transposition if the input geometry matches the one
12086 specified by the specified value. It accepts the following values:
12089 Always apply transposition.
12091 Preserve portrait geometry (when @var{height} >= @var{width}).
12093 Preserve landscape geometry (when @var{width} >= @var{height}).
12096 Default value is @code{none}.
12099 For example to rotate by 90 degrees clockwise and preserve portrait
12102 transpose=dir=1:passthrough=portrait
12105 The command above can also be specified as:
12107 transpose=1:portrait
12111 Trim the input so that the output contains one continuous subpart of the input.
12113 It accepts the following parameters:
12116 Specify the time of the start of the kept section, i.e. the frame with the
12117 timestamp @var{start} will be the first frame in the output.
12120 Specify the time of the first frame that will be dropped, i.e. the frame
12121 immediately preceding the one with the timestamp @var{end} will be the last
12122 frame in the output.
12125 This is the same as @var{start}, except this option sets the start timestamp
12126 in timebase units instead of seconds.
12129 This is the same as @var{end}, except this option sets the end timestamp
12130 in timebase units instead of seconds.
12133 The maximum duration of the output in seconds.
12136 The number of the first frame that should be passed to the output.
12139 The number of the first frame that should be dropped.
12142 @option{start}, @option{end}, and @option{duration} are expressed as time
12143 duration specifications; see
12144 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
12145 for the accepted syntax.
12147 Note that the first two sets of the start/end options and the @option{duration}
12148 option look at the frame timestamp, while the _frame variants simply count the
12149 frames that pass through the filter. Also note that this filter does not modify
12150 the timestamps. If you wish for the output timestamps to start at zero, insert a
12151 setpts filter after the trim filter.
12153 If multiple start or end options are set, this filter tries to be greedy and
12154 keep all the frames that match at least one of the specified constraints. To keep
12155 only the part that matches all the constraints at once, chain multiple trim
12158 The defaults are such that all the input is kept. So it is possible to set e.g.
12159 just the end values to keep everything before the specified time.
12164 Drop everything except the second minute of input:
12166 ffmpeg -i INPUT -vf trim=60:120
12170 Keep only the first second:
12172 ffmpeg -i INPUT -vf trim=duration=1
12181 Sharpen or blur the input video.
12183 It accepts the following parameters:
12186 @item luma_msize_x, lx
12187 Set the luma matrix horizontal size. It must be an odd integer between
12188 3 and 63. The default value is 5.
12190 @item luma_msize_y, ly
12191 Set the luma matrix vertical size. It must be an odd integer between 3
12192 and 63. The default value is 5.
12194 @item luma_amount, la
12195 Set the luma effect strength. It must be a floating point number, reasonable
12196 values lay between -1.5 and 1.5.
12198 Negative values will blur the input video, while positive values will
12199 sharpen it, a value of zero will disable the effect.
12201 Default value is 1.0.
12203 @item chroma_msize_x, cx
12204 Set the chroma matrix horizontal size. It must be an odd integer
12205 between 3 and 63. The default value is 5.
12207 @item chroma_msize_y, cy
12208 Set the chroma matrix vertical size. It must be an odd integer
12209 between 3 and 63. The default value is 5.
12211 @item chroma_amount, ca
12212 Set the chroma effect strength. It must be a floating point number, reasonable
12213 values lay between -1.5 and 1.5.
12215 Negative values will blur the input video, while positive values will
12216 sharpen it, a value of zero will disable the effect.
12218 Default value is 0.0.
12221 If set to 1, specify using OpenCL capabilities, only available if
12222 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
12226 All parameters are optional and default to the equivalent of the
12227 string '5:5:1.0:5:5:0.0'.
12229 @subsection Examples
12233 Apply strong luma sharpen effect:
12235 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
12239 Apply a strong blur of both luma and chroma parameters:
12241 unsharp=7:7:-2:7:7:-2
12247 Apply ultra slow/simple postprocessing filter that compresses and decompresses
12248 the image at several (or - in the case of @option{quality} level @code{8} - all)
12249 shifts and average the results.
12251 The way this differs from the behavior of spp is that uspp actually encodes &
12252 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
12253 DCT similar to MJPEG.
12255 The filter accepts the following options:
12259 Set quality. This option defines the number of levels for averaging. It accepts
12260 an integer in the range 0-8. If set to @code{0}, the filter will have no
12261 effect. A value of @code{8} means the higher quality. For each increment of
12262 that value the speed drops by a factor of approximately 2. Default value is
12266 Force a constant quantization parameter. If not set, the filter will use the QP
12267 from the video stream (if available).
12270 @section vectorscope
12272 Display 2 color component values in the two dimensional graph (which is called
12275 This filter accepts the following options:
12279 Set vectorscope mode.
12281 It accepts the following values:
12284 Gray values are displayed on graph, higher brightness means more pixels have
12285 same component color value on location in graph. This is the default mode.
12288 Gray values are displayed on graph. Surrounding pixels values which are not
12289 present in video frame are drawn in gradient of 2 color components which are
12290 set by option @code{x} and @code{y}.
12293 Actual color components values present in video frame are displayed on graph.
12296 Similar as color2 but higher frequency of same values @code{x} and @code{y}
12297 on graph increases value of another color component, which is luminance by
12298 default values of @code{x} and @code{y}.
12301 Actual colors present in video frame are displayed on graph. If two different
12302 colors map to same position on graph then color with higher value of component
12303 not present in graph is picked.
12307 Set which color component will be represented on X-axis. Default is @code{1}.
12310 Set which color component will be represented on Y-axis. Default is @code{2}.
12313 Set intensity, used by modes: gray, color and color3 for increasing brightness
12314 of color component which represents frequency of (X, Y) location in graph.
12319 No envelope, this is default.
12322 Instant envelope, even darkest single pixel will be clearly highlighted.
12325 Hold maximum and minimum values presented in graph over time. This way you
12326 can still spot out of range values without constantly looking at vectorscope.
12329 Peak and instant envelope combined together.
12333 @anchor{vidstabdetect}
12334 @section vidstabdetect
12336 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
12337 @ref{vidstabtransform} for pass 2.
12339 This filter generates a file with relative translation and rotation
12340 transform information about subsequent frames, which is then used by
12341 the @ref{vidstabtransform} filter.
12343 To enable compilation of this filter you need to configure FFmpeg with
12344 @code{--enable-libvidstab}.
12346 This filter accepts the following options:
12350 Set the path to the file used to write the transforms information.
12351 Default value is @file{transforms.trf}.
12354 Set how shaky the video is and how quick the camera is. It accepts an
12355 integer in the range 1-10, a value of 1 means little shakiness, a
12356 value of 10 means strong shakiness. Default value is 5.
12359 Set the accuracy of the detection process. It must be a value in the
12360 range 1-15. A value of 1 means low accuracy, a value of 15 means high
12361 accuracy. Default value is 15.
12364 Set stepsize of the search process. The region around minimum is
12365 scanned with 1 pixel resolution. Default value is 6.
12368 Set minimum contrast. Below this value a local measurement field is
12369 discarded. Must be a floating point value in the range 0-1. Default
12373 Set reference frame number for tripod mode.
12375 If enabled, the motion of the frames is compared to a reference frame
12376 in the filtered stream, identified by the specified number. The idea
12377 is to compensate all movements in a more-or-less static scene and keep
12378 the camera view absolutely still.
12380 If set to 0, it is disabled. The frames are counted starting from 1.
12383 Show fields and transforms in the resulting frames. It accepts an
12384 integer in the range 0-2. Default value is 0, which disables any
12388 @subsection Examples
12392 Use default values:
12398 Analyze strongly shaky movie and put the results in file
12399 @file{mytransforms.trf}:
12401 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
12405 Visualize the result of internal transformations in the resulting
12408 vidstabdetect=show=1
12412 Analyze a video with medium shakiness using @command{ffmpeg}:
12414 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
12418 @anchor{vidstabtransform}
12419 @section vidstabtransform
12421 Video stabilization/deshaking: pass 2 of 2,
12422 see @ref{vidstabdetect} for pass 1.
12424 Read a file with transform information for each frame and
12425 apply/compensate them. Together with the @ref{vidstabdetect}
12426 filter this can be used to deshake videos. See also
12427 @url{http://public.hronopik.de/vid.stab}. It is important to also use
12428 the @ref{unsharp} filter, see below.
12430 To enable compilation of this filter you need to configure FFmpeg with
12431 @code{--enable-libvidstab}.
12433 @subsection Options
12437 Set path to the file used to read the transforms. Default value is
12438 @file{transforms.trf}.
12441 Set the number of frames (value*2 + 1) used for lowpass filtering the
12442 camera movements. Default value is 10.
12444 For example a number of 10 means that 21 frames are used (10 in the
12445 past and 10 in the future) to smoothen the motion in the video. A
12446 larger value leads to a smoother video, but limits the acceleration of
12447 the camera (pan/tilt movements). 0 is a special case where a static
12448 camera is simulated.
12451 Set the camera path optimization algorithm.
12453 Accepted values are:
12456 gaussian kernel low-pass filter on camera motion (default)
12458 averaging on transformations
12462 Set maximal number of pixels to translate frames. Default value is -1,
12466 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
12467 value is -1, meaning no limit.
12470 Specify how to deal with borders that may be visible due to movement
12473 Available values are:
12476 keep image information from previous frame (default)
12478 fill the border black
12482 Invert transforms if set to 1. Default value is 0.
12485 Consider transforms as relative to previous frame if set to 1,
12486 absolute if set to 0. Default value is 0.
12489 Set percentage to zoom. A positive value will result in a zoom-in
12490 effect, a negative value in a zoom-out effect. Default value is 0 (no
12494 Set optimal zooming to avoid borders.
12496 Accepted values are:
12501 optimal static zoom value is determined (only very strong movements
12502 will lead to visible borders) (default)
12504 optimal adaptive zoom value is determined (no borders will be
12505 visible), see @option{zoomspeed}
12508 Note that the value given at zoom is added to the one calculated here.
12511 Set percent to zoom maximally each frame (enabled when
12512 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
12516 Specify type of interpolation.
12518 Available values are:
12523 linear only horizontal
12525 linear in both directions (default)
12527 cubic in both directions (slow)
12531 Enable virtual tripod mode if set to 1, which is equivalent to
12532 @code{relative=0:smoothing=0}. Default value is 0.
12534 Use also @code{tripod} option of @ref{vidstabdetect}.
12537 Increase log verbosity if set to 1. Also the detected global motions
12538 are written to the temporary file @file{global_motions.trf}. Default
12542 @subsection Examples
12546 Use @command{ffmpeg} for a typical stabilization with default values:
12548 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
12551 Note the use of the @ref{unsharp} filter which is always recommended.
12554 Zoom in a bit more and load transform data from a given file:
12556 vidstabtransform=zoom=5:input="mytransforms.trf"
12560 Smoothen the video even more:
12562 vidstabtransform=smoothing=30
12568 Flip the input video vertically.
12570 For example, to vertically flip a video with @command{ffmpeg}:
12572 ffmpeg -i in.avi -vf "vflip" out.avi
12578 Make or reverse a natural vignetting effect.
12580 The filter accepts the following options:
12584 Set lens angle expression as a number of radians.
12586 The value is clipped in the @code{[0,PI/2]} range.
12588 Default value: @code{"PI/5"}
12592 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
12596 Set forward/backward mode.
12598 Available modes are:
12601 The larger the distance from the central point, the darker the image becomes.
12604 The larger the distance from the central point, the brighter the image becomes.
12605 This can be used to reverse a vignette effect, though there is no automatic
12606 detection to extract the lens @option{angle} and other settings (yet). It can
12607 also be used to create a burning effect.
12610 Default value is @samp{forward}.
12613 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
12615 It accepts the following values:
12618 Evaluate expressions only once during the filter initialization.
12621 Evaluate expressions for each incoming frame. This is way slower than the
12622 @samp{init} mode since it requires all the scalers to be re-computed, but it
12623 allows advanced dynamic expressions.
12626 Default value is @samp{init}.
12629 Set dithering to reduce the circular banding effects. Default is @code{1}
12633 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
12634 Setting this value to the SAR of the input will make a rectangular vignetting
12635 following the dimensions of the video.
12637 Default is @code{1/1}.
12640 @subsection Expressions
12642 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
12643 following parameters.
12648 input width and height
12651 the number of input frame, starting from 0
12654 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
12655 @var{TB} units, NAN if undefined
12658 frame rate of the input video, NAN if the input frame rate is unknown
12661 the PTS (Presentation TimeStamp) of the filtered video frame,
12662 expressed in seconds, NAN if undefined
12665 time base of the input video
12669 @subsection Examples
12673 Apply simple strong vignetting effect:
12679 Make a flickering vignetting:
12681 vignette='PI/4+random(1)*PI/50':eval=frame
12687 Stack input videos vertically.
12689 All streams must be of same pixel format and of same width.
12691 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
12692 to create same output.
12694 The filter accept the following option:
12698 Set number of input streams. Default is 2.
12701 If set to 1, force the output to terminate when the shortest input
12702 terminates. Default value is 0.
12707 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
12708 Deinterlacing Filter").
12710 Based on the process described by Martin Weston for BBC R&D, and
12711 implemented based on the de-interlace algorithm written by Jim
12712 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
12713 uses filter coefficients calculated by BBC R&D.
12715 There are two sets of filter coefficients, so called "simple":
12716 and "complex". Which set of filter coefficients is used can
12717 be set by passing an optional parameter:
12721 Set the interlacing filter coefficients. Accepts one of the following values:
12725 Simple filter coefficient set.
12727 More-complex filter coefficient set.
12729 Default value is @samp{complex}.
12732 Specify which frames to deinterlace. Accept one of the following values:
12736 Deinterlace all frames,
12738 Only deinterlace frames marked as interlaced.
12741 Default value is @samp{all}.
12745 Video waveform monitor.
12747 The waveform monitor plots color component intensity. By default luminance
12748 only. Each column of the waveform corresponds to a column of pixels in the
12751 It accepts the following options:
12755 Can be either @code{row}, or @code{column}. Default is @code{column}.
12756 In row mode, the graph on the left side represents color component value 0 and
12757 the right side represents value = 255. In column mode, the top side represents
12758 color component value = 0 and bottom side represents value = 255.
12761 Set intensity. Smaller values are useful to find out how many values of the same
12762 luminance are distributed across input rows/columns.
12763 Default value is @code{0.04}. Allowed range is [0, 1].
12766 Set mirroring mode. @code{0} means unmirrored, @code{1} means mirrored.
12767 In mirrored mode, higher values will be represented on the left
12768 side for @code{row} mode and at the top for @code{column} mode. Default is
12769 @code{1} (mirrored).
12773 It accepts the following values:
12776 Presents information identical to that in the @code{parade}, except
12777 that the graphs representing color components are superimposed directly
12780 This display mode makes it easier to spot relative differences or similarities
12781 in overlapping areas of the color components that are supposed to be identical,
12782 such as neutral whites, grays, or blacks.
12785 Display separate graph for the color components side by side in
12786 @code{row} mode or one below the other in @code{column} mode.
12788 Using this display mode makes it easy to spot color casts in the highlights
12789 and shadows of an image, by comparing the contours of the top and the bottom
12790 graphs of each waveform. Since whites, grays, and blacks are characterized
12791 by exactly equal amounts of red, green, and blue, neutral areas of the picture
12792 should display three waveforms of roughly equal width/height. If not, the
12793 correction is easy to perform by making level adjustments the three waveforms.
12795 Default is @code{parade}.
12797 @item components, c
12798 Set which color components to display. Default is 1, which means only luminance
12799 or red color component if input is in RGB colorspace. If is set for example to
12800 7 it will display all 3 (if) available color components.
12805 No envelope, this is default.
12808 Instant envelope, minimum and maximum values presented in graph will be easily
12809 visible even with small @code{step} value.
12812 Hold minimum and maximum values presented in graph across time. This way you
12813 can still spot out of range values without constantly looking at waveforms.
12816 Peak and instant envelope combined together.
12822 No filtering, this is default.
12825 Luma and chroma combined together.
12828 Similar as above, but shows difference between blue and red chroma.
12831 Displays only chroma.
12834 Similar as above, but shows difference between blue and red chroma.
12837 Displays actual color value on waveform.
12842 Apply the xBR high-quality magnification filter which is designed for pixel
12843 art. It follows a set of edge-detection rules, see
12844 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
12846 It accepts the following option:
12850 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
12851 @code{3xBR} and @code{4} for @code{4xBR}.
12852 Default is @code{3}.
12858 Deinterlace the input video ("yadif" means "yet another deinterlacing
12861 It accepts the following parameters:
12867 The interlacing mode to adopt. It accepts one of the following values:
12870 @item 0, send_frame
12871 Output one frame for each frame.
12872 @item 1, send_field
12873 Output one frame for each field.
12874 @item 2, send_frame_nospatial
12875 Like @code{send_frame}, but it skips the spatial interlacing check.
12876 @item 3, send_field_nospatial
12877 Like @code{send_field}, but it skips the spatial interlacing check.
12880 The default value is @code{send_frame}.
12883 The picture field parity assumed for the input interlaced video. It accepts one
12884 of the following values:
12888 Assume the top field is first.
12890 Assume the bottom field is first.
12892 Enable automatic detection of field parity.
12895 The default value is @code{auto}.
12896 If the interlacing is unknown or the decoder does not export this information,
12897 top field first will be assumed.
12900 Specify which frames to deinterlace. Accept one of the following
12905 Deinterlace all frames.
12906 @item 1, interlaced
12907 Only deinterlace frames marked as interlaced.
12910 The default value is @code{all}.
12915 Apply Zoom & Pan effect.
12917 This filter accepts the following options:
12921 Set the zoom expression. Default is 1.
12925 Set the x and y expression. Default is 0.
12928 Set the duration expression in number of frames.
12929 This sets for how many number of frames effect will last for
12930 single input image.
12933 Set the output image size, default is 'hd720'.
12936 Set the output frame rate, default is '25'.
12939 Each expression can contain the following constants:
12958 Output frame count.
12962 Last calculated 'x' and 'y' position from 'x' and 'y' expression
12963 for current input frame.
12967 'x' and 'y' of last output frame of previous input frame or 0 when there was
12968 not yet such frame (first input frame).
12971 Last calculated zoom from 'z' expression for current input frame.
12974 Last calculated zoom of last output frame of previous input frame.
12977 Number of output frames for current input frame. Calculated from 'd' expression
12978 for each input frame.
12981 number of output frames created for previous input frame
12984 Rational number: input width / input height
12987 sample aspect ratio
12990 display aspect ratio
12994 @subsection Examples
12998 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
13000 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
13004 Zoom-in up to 1.5 and pan always at center of picture:
13006 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
13011 Scale (resize) the input video, using the z.lib library:
13012 https://github.com/sekrit-twc/zimg.
13014 The zscale filter forces the output display aspect ratio to be the same
13015 as the input, by changing the output sample aspect ratio.
13017 If the input image format is different from the format requested by
13018 the next filter, the zscale filter will convert the input to the
13021 @subsection Options
13022 The filter accepts the following options.
13027 Set the output video dimension expression. Default value is the input
13030 If the @var{width} or @var{w} is 0, the input width is used for the output.
13031 If the @var{height} or @var{h} is 0, the input height is used for the output.
13033 If one of the values is -1, the zscale filter will use a value that
13034 maintains the aspect ratio of the input image, calculated from the
13035 other specified dimension. If both of them are -1, the input size is
13038 If one of the values is -n with n > 1, the zscale filter will also use a value
13039 that maintains the aspect ratio of the input image, calculated from the other
13040 specified dimension. After that it will, however, make sure that the calculated
13041 dimension is divisible by n and adjust the value if necessary.
13043 See below for the list of accepted constants for use in the dimension
13047 Set the video size. For the syntax of this option, check the
13048 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13051 Set the dither type.
13053 Possible values are:
13058 @item error_diffusion
13064 Set the resize filter type.
13066 Possible values are:
13076 Default is bilinear.
13079 Set the color range.
13081 Possible values are:
13088 Default is same as input.
13091 Set the color primaries.
13093 Possible values are:
13103 Default is same as input.
13106 Set the transfer characteristics.
13108 Possible values are:
13119 Default is same as input.
13122 Set the colorspace matrix.
13124 Possible value are:
13135 Default is same as input.
13138 Set the input color range.
13140 Possible values are:
13147 Default is same as input.
13149 @item primariesin, pin
13150 Set the input color primaries.
13152 Possible values are:
13162 Default is same as input.
13164 @item transferin, tin
13165 Set the input transfer characteristics.
13167 Possible values are:
13178 Default is same as input.
13180 @item matrixin, min
13181 Set the input colorspace matrix.
13183 Possible value are:
13195 The values of the @option{w} and @option{h} options are expressions
13196 containing the following constants:
13201 The input width and height
13205 These are the same as @var{in_w} and @var{in_h}.
13209 The output (scaled) width and height
13213 These are the same as @var{out_w} and @var{out_h}
13216 The same as @var{iw} / @var{ih}
13219 input sample aspect ratio
13222 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
13226 horizontal and vertical input chroma subsample values. For example for the
13227 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
13231 horizontal and vertical output chroma subsample values. For example for the
13232 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
13238 @c man end VIDEO FILTERS
13240 @chapter Video Sources
13241 @c man begin VIDEO SOURCES
13243 Below is a description of the currently available video sources.
13247 Buffer video frames, and make them available to the filter chain.
13249 This source is mainly intended for a programmatic use, in particular
13250 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
13252 It accepts the following parameters:
13257 Specify the size (width and height) of the buffered video frames. For the
13258 syntax of this option, check the
13259 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13262 The input video width.
13265 The input video height.
13268 A string representing the pixel format of the buffered video frames.
13269 It may be a number corresponding to a pixel format, or a pixel format
13273 Specify the timebase assumed by the timestamps of the buffered frames.
13276 Specify the frame rate expected for the video stream.
13278 @item pixel_aspect, sar
13279 The sample (pixel) aspect ratio of the input video.
13282 Specify the optional parameters to be used for the scale filter which
13283 is automatically inserted when an input change is detected in the
13284 input size or format.
13289 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
13292 will instruct the source to accept video frames with size 320x240 and
13293 with format "yuv410p", assuming 1/24 as the timestamps timebase and
13294 square pixels (1:1 sample aspect ratio).
13295 Since the pixel format with name "yuv410p" corresponds to the number 6
13296 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
13297 this example corresponds to:
13299 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
13302 Alternatively, the options can be specified as a flat string, but this
13303 syntax is deprecated:
13305 @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}]
13309 Create a pattern generated by an elementary cellular automaton.
13311 The initial state of the cellular automaton can be defined through the
13312 @option{filename}, and @option{pattern} options. If such options are
13313 not specified an initial state is created randomly.
13315 At each new frame a new row in the video is filled with the result of
13316 the cellular automaton next generation. The behavior when the whole
13317 frame is filled is defined by the @option{scroll} option.
13319 This source accepts the following options:
13323 Read the initial cellular automaton state, i.e. the starting row, from
13324 the specified file.
13325 In the file, each non-whitespace character is considered an alive
13326 cell, a newline will terminate the row, and further characters in the
13327 file will be ignored.
13330 Read the initial cellular automaton state, i.e. the starting row, from
13331 the specified string.
13333 Each non-whitespace character in the string is considered an alive
13334 cell, a newline will terminate the row, and further characters in the
13335 string will be ignored.
13338 Set the video rate, that is the number of frames generated per second.
13341 @item random_fill_ratio, ratio
13342 Set the random fill ratio for the initial cellular automaton row. It
13343 is a floating point number value ranging from 0 to 1, defaults to
13346 This option is ignored when a file or a pattern is specified.
13348 @item random_seed, seed
13349 Set the seed for filling randomly the initial row, must be an integer
13350 included between 0 and UINT32_MAX. If not specified, or if explicitly
13351 set to -1, the filter will try to use a good random seed on a best
13355 Set the cellular automaton rule, it is a number ranging from 0 to 255.
13356 Default value is 110.
13359 Set the size of the output video. For the syntax of this option, check the
13360 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13362 If @option{filename} or @option{pattern} is specified, the size is set
13363 by default to the width of the specified initial state row, and the
13364 height is set to @var{width} * PHI.
13366 If @option{size} is set, it must contain the width of the specified
13367 pattern string, and the specified pattern will be centered in the
13370 If a filename or a pattern string is not specified, the size value
13371 defaults to "320x518" (used for a randomly generated initial state).
13374 If set to 1, scroll the output upward when all the rows in the output
13375 have been already filled. If set to 0, the new generated row will be
13376 written over the top row just after the bottom row is filled.
13379 @item start_full, full
13380 If set to 1, completely fill the output with generated rows before
13381 outputting the first frame.
13382 This is the default behavior, for disabling set the value to 0.
13385 If set to 1, stitch the left and right row edges together.
13386 This is the default behavior, for disabling set the value to 0.
13389 @subsection Examples
13393 Read the initial state from @file{pattern}, and specify an output of
13396 cellauto=f=pattern:s=200x400
13400 Generate a random initial row with a width of 200 cells, with a fill
13403 cellauto=ratio=2/3:s=200x200
13407 Create a pattern generated by rule 18 starting by a single alive cell
13408 centered on an initial row with width 100:
13410 cellauto=p=@@:s=100x400:full=0:rule=18
13414 Specify a more elaborated initial pattern:
13416 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
13421 @section mandelbrot
13423 Generate a Mandelbrot set fractal, and progressively zoom towards the
13424 point specified with @var{start_x} and @var{start_y}.
13426 This source accepts the following options:
13431 Set the terminal pts value. Default value is 400.
13434 Set the terminal scale value.
13435 Must be a floating point value. Default value is 0.3.
13438 Set the inner coloring mode, that is the algorithm used to draw the
13439 Mandelbrot fractal internal region.
13441 It shall assume one of the following values:
13446 Show time until convergence.
13448 Set color based on point closest to the origin of the iterations.
13453 Default value is @var{mincol}.
13456 Set the bailout value. Default value is 10.0.
13459 Set the maximum of iterations performed by the rendering
13460 algorithm. Default value is 7189.
13463 Set outer coloring mode.
13464 It shall assume one of following values:
13466 @item iteration_count
13467 Set iteration cound mode.
13468 @item normalized_iteration_count
13469 set normalized iteration count mode.
13471 Default value is @var{normalized_iteration_count}.
13474 Set frame rate, expressed as number of frames per second. Default
13478 Set frame size. For the syntax of this option, check the "Video
13479 size" section in the ffmpeg-utils manual. Default value is "640x480".
13482 Set the initial scale value. Default value is 3.0.
13485 Set the initial x position. Must be a floating point value between
13486 -100 and 100. Default value is -0.743643887037158704752191506114774.
13489 Set the initial y position. Must be a floating point value between
13490 -100 and 100. Default value is -0.131825904205311970493132056385139.
13495 Generate various test patterns, as generated by the MPlayer test filter.
13497 The size of the generated video is fixed, and is 256x256.
13498 This source is useful in particular for testing encoding features.
13500 This source accepts the following options:
13505 Specify the frame rate of the sourced video, as the number of frames
13506 generated per second. It has to be a string in the format
13507 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
13508 number or a valid video frame rate abbreviation. The default value is
13512 Set the duration of the sourced video. See
13513 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
13514 for the accepted syntax.
13516 If not specified, or the expressed duration is negative, the video is
13517 supposed to be generated forever.
13521 Set the number or the name of the test to perform. Supported tests are:
13537 Default value is "all", which will cycle through the list of all tests.
13542 mptestsrc=t=dc_luma
13545 will generate a "dc_luma" test pattern.
13547 @section frei0r_src
13549 Provide a frei0r source.
13551 To enable compilation of this filter you need to install the frei0r
13552 header and configure FFmpeg with @code{--enable-frei0r}.
13554 This source accepts the following parameters:
13559 The size of the video to generate. For the syntax of this option, check the
13560 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13563 The framerate of the generated video. It may be a string of the form
13564 @var{num}/@var{den} or a frame rate abbreviation.
13567 The name to the frei0r source to load. For more information regarding frei0r and
13568 how to set the parameters, read the @ref{frei0r} section in the video filters
13571 @item filter_params
13572 A '|'-separated list of parameters to pass to the frei0r source.
13576 For example, to generate a frei0r partik0l source with size 200x200
13577 and frame rate 10 which is overlaid on the overlay filter main input:
13579 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
13584 Generate a life pattern.
13586 This source is based on a generalization of John Conway's life game.
13588 The sourced input represents a life grid, each pixel represents a cell
13589 which can be in one of two possible states, alive or dead. Every cell
13590 interacts with its eight neighbours, which are the cells that are
13591 horizontally, vertically, or diagonally adjacent.
13593 At each interaction the grid evolves according to the adopted rule,
13594 which specifies the number of neighbor alive cells which will make a
13595 cell stay alive or born. The @option{rule} option allows one to specify
13598 This source accepts the following options:
13602 Set the file from which to read the initial grid state. In the file,
13603 each non-whitespace character is considered an alive cell, and newline
13604 is used to delimit the end of each row.
13606 If this option is not specified, the initial grid is generated
13610 Set the video rate, that is the number of frames generated per second.
13613 @item random_fill_ratio, ratio
13614 Set the random fill ratio for the initial random grid. It is a
13615 floating point number value ranging from 0 to 1, defaults to 1/PHI.
13616 It is ignored when a file is specified.
13618 @item random_seed, seed
13619 Set the seed for filling the initial random grid, must be an integer
13620 included between 0 and UINT32_MAX. If not specified, or if explicitly
13621 set to -1, the filter will try to use a good random seed on a best
13627 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
13628 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
13629 @var{NS} specifies the number of alive neighbor cells which make a
13630 live cell stay alive, and @var{NB} the number of alive neighbor cells
13631 which make a dead cell to become alive (i.e. to "born").
13632 "s" and "b" can be used in place of "S" and "B", respectively.
13634 Alternatively a rule can be specified by an 18-bits integer. The 9
13635 high order bits are used to encode the next cell state if it is alive
13636 for each number of neighbor alive cells, the low order bits specify
13637 the rule for "borning" new cells. Higher order bits encode for an
13638 higher number of neighbor cells.
13639 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
13640 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
13642 Default value is "S23/B3", which is the original Conway's game of life
13643 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
13644 cells, and will born a new cell if there are three alive cells around
13648 Set the size of the output video. For the syntax of this option, check the
13649 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13651 If @option{filename} is specified, the size is set by default to the
13652 same size of the input file. If @option{size} is set, it must contain
13653 the size specified in the input file, and the initial grid defined in
13654 that file is centered in the larger resulting area.
13656 If a filename is not specified, the size value defaults to "320x240"
13657 (used for a randomly generated initial grid).
13660 If set to 1, stitch the left and right grid edges together, and the
13661 top and bottom edges also. Defaults to 1.
13664 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
13665 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
13666 value from 0 to 255.
13669 Set the color of living (or new born) cells.
13672 Set the color of dead cells. If @option{mold} is set, this is the first color
13673 used to represent a dead cell.
13676 Set mold color, for definitely dead and moldy cells.
13678 For the syntax of these 3 color options, check the "Color" section in the
13679 ffmpeg-utils manual.
13682 @subsection Examples
13686 Read a grid from @file{pattern}, and center it on a grid of size
13689 life=f=pattern:s=300x300
13693 Generate a random grid of size 200x200, with a fill ratio of 2/3:
13695 life=ratio=2/3:s=200x200
13699 Specify a custom rule for evolving a randomly generated grid:
13705 Full example with slow death effect (mold) using @command{ffplay}:
13707 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
13714 @anchor{haldclutsrc}
13716 @anchor{rgbtestsrc}
13718 @anchor{smptehdbars}
13720 @section allrgb, allyuv, color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
13722 The @code{allrgb} source returns frames of size 4096x4096 of all rgb colors.
13724 The @code{allyuv} source returns frames of size 4096x4096 of all yuv colors.
13726 The @code{color} source provides an uniformly colored input.
13728 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
13729 @ref{haldclut} filter.
13731 The @code{nullsrc} source returns unprocessed video frames. It is
13732 mainly useful to be employed in analysis / debugging tools, or as the
13733 source for filters which ignore the input data.
13735 The @code{rgbtestsrc} source generates an RGB test pattern useful for
13736 detecting RGB vs BGR issues. You should see a red, green and blue
13737 stripe from top to bottom.
13739 The @code{smptebars} source generates a color bars pattern, based on
13740 the SMPTE Engineering Guideline EG 1-1990.
13742 The @code{smptehdbars} source generates a color bars pattern, based on
13743 the SMPTE RP 219-2002.
13745 The @code{testsrc} source generates a test video pattern, showing a
13746 color pattern, a scrolling gradient and a timestamp. This is mainly
13747 intended for testing purposes.
13749 The sources accept the following parameters:
13754 Specify the color of the source, only available in the @code{color}
13755 source. For the syntax of this option, check the "Color" section in the
13756 ffmpeg-utils manual.
13759 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
13760 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
13761 pixels to be used as identity matrix for 3D lookup tables. Each component is
13762 coded on a @code{1/(N*N)} scale.
13765 Specify the size of the sourced video. For the syntax of this option, check the
13766 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13767 The default value is @code{320x240}.
13769 This option is not available with the @code{haldclutsrc} filter.
13772 Specify the frame rate of the sourced video, as the number of frames
13773 generated per second. It has to be a string in the format
13774 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
13775 number or a valid video frame rate abbreviation. The default value is
13779 Set the sample aspect ratio of the sourced video.
13782 Set the duration of the sourced video. See
13783 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
13784 for the accepted syntax.
13786 If not specified, or the expressed duration is negative, the video is
13787 supposed to be generated forever.
13790 Set the number of decimals to show in the timestamp, only available in the
13791 @code{testsrc} source.
13793 The displayed timestamp value will correspond to the original
13794 timestamp value multiplied by the power of 10 of the specified
13795 value. Default value is 0.
13798 For example the following:
13800 testsrc=duration=5.3:size=qcif:rate=10
13803 will generate a video with a duration of 5.3 seconds, with size
13804 176x144 and a frame rate of 10 frames per second.
13806 The following graph description will generate a red source
13807 with an opacity of 0.2, with size "qcif" and a frame rate of 10
13810 color=c=red@@0.2:s=qcif:r=10
13813 If the input content is to be ignored, @code{nullsrc} can be used. The
13814 following command generates noise in the luminance plane by employing
13815 the @code{geq} filter:
13817 nullsrc=s=256x256, geq=random(1)*255:128:128
13820 @subsection Commands
13822 The @code{color} source supports the following commands:
13826 Set the color of the created image. Accepts the same syntax of the
13827 corresponding @option{color} option.
13830 @c man end VIDEO SOURCES
13832 @chapter Video Sinks
13833 @c man begin VIDEO SINKS
13835 Below is a description of the currently available video sinks.
13837 @section buffersink
13839 Buffer video frames, and make them available to the end of the filter
13842 This sink is mainly intended for programmatic use, in particular
13843 through the interface defined in @file{libavfilter/buffersink.h}
13844 or the options system.
13846 It accepts a pointer to an AVBufferSinkContext structure, which
13847 defines the incoming buffers' formats, to be passed as the opaque
13848 parameter to @code{avfilter_init_filter} for initialization.
13852 Null video sink: do absolutely nothing with the input video. It is
13853 mainly useful as a template and for use in analysis / debugging
13856 @c man end VIDEO SINKS
13858 @chapter Multimedia Filters
13859 @c man begin MULTIMEDIA FILTERS
13861 Below is a description of the currently available multimedia filters.
13863 @section ahistogram
13865 Convert input audio to a video output, displaying the volume histogram.
13867 The filter accepts the following options:
13871 Specify how histogram is calculated.
13873 It accepts the following values:
13876 Use single histogram for all channels.
13878 Use separate histogram for each channel.
13880 Default is @code{single}.
13883 Set frame rate, expressed as number of frames per second. Default
13887 Specify the video size for the output. For the syntax of this option, check the
13888 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13889 Default value is @code{hd720}.
13894 It accepts the following values:
13905 reverse logarithmic
13907 Default is @code{log}.
13910 Set amplitude scale.
13912 It accepts the following values:
13919 Default is @code{log}.
13922 Set how much frames to accumulate in histogram.
13923 Defauls is 1. Setting this to -1 accumulates all frames.
13926 Set histogram ratio of window height.
13929 Set sonogram sliding.
13931 It accepts the following values:
13934 replace old rows with new ones.
13936 scroll from top to bottom.
13938 Default is @code{replace}.
13941 @section aphasemeter
13943 Convert input audio to a video output, displaying the audio phase.
13945 The filter accepts the following options:
13949 Set the output frame rate. Default value is @code{25}.
13952 Set the video size for the output. For the syntax of this option, check the
13953 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13954 Default value is @code{800x400}.
13959 Specify the red, green, blue contrast. Default values are @code{2},
13960 @code{7} and @code{1}.
13961 Allowed range is @code{[0, 255]}.
13964 Set color which will be used for drawing median phase. If color is
13965 @code{none} which is default, no median phase value will be drawn.
13968 The filter also exports the frame metadata @code{lavfi.aphasemeter.phase} which
13969 represents mean phase of current audio frame. Value is in range @code{[-1, 1]}.
13970 The @code{-1} means left and right channels are completely out of phase and
13971 @code{1} means channels are in phase.
13973 @section avectorscope
13975 Convert input audio to a video output, representing the audio vector
13978 The filter is used to measure the difference between channels of stereo
13979 audio stream. A monoaural signal, consisting of identical left and right
13980 signal, results in straight vertical line. Any stereo separation is visible
13981 as a deviation from this line, creating a Lissajous figure.
13982 If the straight (or deviation from it) but horizontal line appears this
13983 indicates that the left and right channels are out of phase.
13985 The filter accepts the following options:
13989 Set the vectorscope mode.
13991 Available values are:
13994 Lissajous rotated by 45 degrees.
13997 Same as above but not rotated.
14000 Shape resembling half of circle.
14003 Default value is @samp{lissajous}.
14006 Set the video size for the output. For the syntax of this option, check the
14007 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14008 Default value is @code{400x400}.
14011 Set the output frame rate. Default value is @code{25}.
14017 Specify the red, green, blue and alpha contrast. Default values are @code{40},
14018 @code{160}, @code{80} and @code{255}.
14019 Allowed range is @code{[0, 255]}.
14025 Specify the red, green, blue and alpha fade. Default values are @code{15},
14026 @code{10}, @code{5} and @code{5}.
14027 Allowed range is @code{[0, 255]}.
14030 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
14033 Set the vectorscope drawing mode.
14035 Available values are:
14038 Draw dot for each sample.
14041 Draw line between previous and current sample.
14044 Default value is @samp{dot}.
14047 @subsection Examples
14051 Complete example using @command{ffplay}:
14053 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
14054 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
14060 Concatenate audio and video streams, joining them together one after the
14063 The filter works on segments of synchronized video and audio streams. All
14064 segments must have the same number of streams of each type, and that will
14065 also be the number of streams at output.
14067 The filter accepts the following options:
14072 Set the number of segments. Default is 2.
14075 Set the number of output video streams, that is also the number of video
14076 streams in each segment. Default is 1.
14079 Set the number of output audio streams, that is also the number of audio
14080 streams in each segment. Default is 0.
14083 Activate unsafe mode: do not fail if segments have a different format.
14087 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
14088 @var{a} audio outputs.
14090 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
14091 segment, in the same order as the outputs, then the inputs for the second
14094 Related streams do not always have exactly the same duration, for various
14095 reasons including codec frame size or sloppy authoring. For that reason,
14096 related synchronized streams (e.g. a video and its audio track) should be
14097 concatenated at once. The concat filter will use the duration of the longest
14098 stream in each segment (except the last one), and if necessary pad shorter
14099 audio streams with silence.
14101 For this filter to work correctly, all segments must start at timestamp 0.
14103 All corresponding streams must have the same parameters in all segments; the
14104 filtering system will automatically select a common pixel format for video
14105 streams, and a common sample format, sample rate and channel layout for
14106 audio streams, but other settings, such as resolution, must be converted
14107 explicitly by the user.
14109 Different frame rates are acceptable but will result in variable frame rate
14110 at output; be sure to configure the output file to handle it.
14112 @subsection Examples
14116 Concatenate an opening, an episode and an ending, all in bilingual version
14117 (video in stream 0, audio in streams 1 and 2):
14119 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
14120 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
14121 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
14122 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
14126 Concatenate two parts, handling audio and video separately, using the
14127 (a)movie sources, and adjusting the resolution:
14129 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
14130 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
14131 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
14133 Note that a desync will happen at the stitch if the audio and video streams
14134 do not have exactly the same duration in the first file.
14141 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
14142 it unchanged. By default, it logs a message at a frequency of 10Hz with the
14143 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
14144 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
14146 The filter also has a video output (see the @var{video} option) with a real
14147 time graph to observe the loudness evolution. The graphic contains the logged
14148 message mentioned above, so it is not printed anymore when this option is set,
14149 unless the verbose logging is set. The main graphing area contains the
14150 short-term loudness (3 seconds of analysis), and the gauge on the right is for
14151 the momentary loudness (400 milliseconds).
14153 More information about the Loudness Recommendation EBU R128 on
14154 @url{http://tech.ebu.ch/loudness}.
14156 The filter accepts the following options:
14161 Activate the video output. The audio stream is passed unchanged whether this
14162 option is set or no. The video stream will be the first output stream if
14163 activated. Default is @code{0}.
14166 Set the video size. This option is for video only. For the syntax of this
14168 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14169 Default and minimum resolution is @code{640x480}.
14172 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
14173 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
14174 other integer value between this range is allowed.
14177 Set metadata injection. If set to @code{1}, the audio input will be segmented
14178 into 100ms output frames, each of them containing various loudness information
14179 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
14181 Default is @code{0}.
14184 Force the frame logging level.
14186 Available values are:
14189 information logging level
14191 verbose logging level
14194 By default, the logging level is set to @var{info}. If the @option{video} or
14195 the @option{metadata} options are set, it switches to @var{verbose}.
14200 Available modes can be cumulated (the option is a @code{flag} type). Possible
14204 Disable any peak mode (default).
14206 Enable sample-peak mode.
14208 Simple peak mode looking for the higher sample value. It logs a message
14209 for sample-peak (identified by @code{SPK}).
14211 Enable true-peak mode.
14213 If enabled, the peak lookup is done on an over-sampled version of the input
14214 stream for better peak accuracy. It logs a message for true-peak.
14215 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
14216 This mode requires a build with @code{libswresample}.
14220 Treat mono input files as "dual mono". If a mono file is intended for playback
14221 on a stereo system, its EBU R128 measurement will be perceptually incorrect.
14222 If set to @code{true}, this option will compensate for this effect.
14223 Multi-channel input files are not affected by this option.
14226 Set a specific pan law to be used for the measurement of dual mono files.
14227 This parameter is optional, and has a default value of -3.01dB.
14230 @subsection Examples
14234 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
14236 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
14240 Run an analysis with @command{ffmpeg}:
14242 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
14246 @section interleave, ainterleave
14248 Temporally interleave frames from several inputs.
14250 @code{interleave} works with video inputs, @code{ainterleave} with audio.
14252 These filters read frames from several inputs and send the oldest
14253 queued frame to the output.
14255 Input streams must have a well defined, monotonically increasing frame
14258 In order to submit one frame to output, these filters need to enqueue
14259 at least one frame for each input, so they cannot work in case one
14260 input is not yet terminated and will not receive incoming frames.
14262 For example consider the case when one input is a @code{select} filter
14263 which always drop input frames. The @code{interleave} filter will keep
14264 reading from that input, but it will never be able to send new frames
14265 to output until the input will send an end-of-stream signal.
14267 Also, depending on inputs synchronization, the filters will drop
14268 frames in case one input receives more frames than the other ones, and
14269 the queue is already filled.
14271 These filters accept the following options:
14275 Set the number of different inputs, it is 2 by default.
14278 @subsection Examples
14282 Interleave frames belonging to different streams using @command{ffmpeg}:
14284 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
14288 Add flickering blur effect:
14290 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
14294 @section perms, aperms
14296 Set read/write permissions for the output frames.
14298 These filters are mainly aimed at developers to test direct path in the
14299 following filter in the filtergraph.
14301 The filters accept the following options:
14305 Select the permissions mode.
14307 It accepts the following values:
14310 Do nothing. This is the default.
14312 Set all the output frames read-only.
14314 Set all the output frames directly writable.
14316 Make the frame read-only if writable, and writable if read-only.
14318 Set each output frame read-only or writable randomly.
14322 Set the seed for the @var{random} mode, must be an integer included between
14323 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
14324 @code{-1}, the filter will try to use a good random seed on a best effort
14328 Note: in case of auto-inserted filter between the permission filter and the
14329 following one, the permission might not be received as expected in that
14330 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
14331 perms/aperms filter can avoid this problem.
14333 @section realtime, arealtime
14335 Slow down filtering to match real time approximatively.
14337 These filters will pause the filtering for a variable amount of time to
14338 match the output rate with the input timestamps.
14339 They are similar to the @option{re} option to @code{ffmpeg}.
14341 They accept the following options:
14345 Time limit for the pauses. Any pause longer than that will be considered
14346 a timestamp discontinuity and reset the timer. Default is 2 seconds.
14349 @section select, aselect
14351 Select frames to pass in output.
14353 This filter accepts the following options:
14358 Set expression, which is evaluated for each input frame.
14360 If the expression is evaluated to zero, the frame is discarded.
14362 If the evaluation result is negative or NaN, the frame is sent to the
14363 first output; otherwise it is sent to the output with index
14364 @code{ceil(val)-1}, assuming that the input index starts from 0.
14366 For example a value of @code{1.2} corresponds to the output with index
14367 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
14370 Set the number of outputs. The output to which to send the selected
14371 frame is based on the result of the evaluation. Default value is 1.
14374 The expression can contain the following constants:
14378 The (sequential) number of the filtered frame, starting from 0.
14381 The (sequential) number of the selected frame, starting from 0.
14383 @item prev_selected_n
14384 The sequential number of the last selected frame. It's NAN if undefined.
14387 The timebase of the input timestamps.
14390 The PTS (Presentation TimeStamp) of the filtered video frame,
14391 expressed in @var{TB} units. It's NAN if undefined.
14394 The PTS of the filtered video frame,
14395 expressed in seconds. It's NAN if undefined.
14398 The PTS of the previously filtered video frame. It's NAN if undefined.
14400 @item prev_selected_pts
14401 The PTS of the last previously filtered video frame. It's NAN if undefined.
14403 @item prev_selected_t
14404 The PTS of the last previously selected video frame. It's NAN if undefined.
14407 The PTS of the first video frame in the video. It's NAN if undefined.
14410 The time of the first video frame in the video. It's NAN if undefined.
14412 @item pict_type @emph{(video only)}
14413 The type of the filtered frame. It can assume one of the following
14425 @item interlace_type @emph{(video only)}
14426 The frame interlace type. It can assume one of the following values:
14429 The frame is progressive (not interlaced).
14431 The frame is top-field-first.
14433 The frame is bottom-field-first.
14436 @item consumed_sample_n @emph{(audio only)}
14437 the number of selected samples before the current frame
14439 @item samples_n @emph{(audio only)}
14440 the number of samples in the current frame
14442 @item sample_rate @emph{(audio only)}
14443 the input sample rate
14446 This is 1 if the filtered frame is a key-frame, 0 otherwise.
14449 the position in the file of the filtered frame, -1 if the information
14450 is not available (e.g. for synthetic video)
14452 @item scene @emph{(video only)}
14453 value between 0 and 1 to indicate a new scene; a low value reflects a low
14454 probability for the current frame to introduce a new scene, while a higher
14455 value means the current frame is more likely to be one (see the example below)
14457 @item concatdec_select
14458 The concat demuxer can select only part of a concat input file by setting an
14459 inpoint and an outpoint, but the output packets may not be entirely contained
14460 in the selected interval. By using this variable, it is possible to skip frames
14461 generated by the concat demuxer which are not exactly contained in the selected
14464 This works by comparing the frame pts against the @var{lavf.concat.start_time}
14465 and the @var{lavf.concat.duration} packet metadata values which are also
14466 present in the decoded frames.
14468 The @var{concatdec_select} variable is -1 if the frame pts is at least
14469 start_time and either the duration metadata is missing or the frame pts is less
14470 than start_time + duration, 0 otherwise, and NaN if the start_time metadata is
14473 That basically means that an input frame is selected if its pts is within the
14474 interval set by the concat demuxer.
14478 The default value of the select expression is "1".
14480 @subsection Examples
14484 Select all frames in input:
14489 The example above is the same as:
14501 Select only I-frames:
14503 select='eq(pict_type\,I)'
14507 Select one frame every 100:
14509 select='not(mod(n\,100))'
14513 Select only frames contained in the 10-20 time interval:
14515 select=between(t\,10\,20)
14519 Select only I frames contained in the 10-20 time interval:
14521 select=between(t\,10\,20)*eq(pict_type\,I)
14525 Select frames with a minimum distance of 10 seconds:
14527 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
14531 Use aselect to select only audio frames with samples number > 100:
14533 aselect='gt(samples_n\,100)'
14537 Create a mosaic of the first scenes:
14539 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
14542 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
14546 Send even and odd frames to separate outputs, and compose them:
14548 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
14552 Select useful frames from an ffconcat file which is using inpoints and
14553 outpoints but where the source files are not intra frame only.
14555 ffmpeg -copyts -vsync 0 -segment_time_metadata 1 -i input.ffconcat -vf select=concatdec_select -af aselect=concatdec_select output.avi
14559 @section sendcmd, asendcmd
14561 Send commands to filters in the filtergraph.
14563 These filters read commands to be sent to other filters in the
14566 @code{sendcmd} must be inserted between two video filters,
14567 @code{asendcmd} must be inserted between two audio filters, but apart
14568 from that they act the same way.
14570 The specification of commands can be provided in the filter arguments
14571 with the @var{commands} option, or in a file specified by the
14572 @var{filename} option.
14574 These filters accept the following options:
14577 Set the commands to be read and sent to the other filters.
14579 Set the filename of the commands to be read and sent to the other
14583 @subsection Commands syntax
14585 A commands description consists of a sequence of interval
14586 specifications, comprising a list of commands to be executed when a
14587 particular event related to that interval occurs. The occurring event
14588 is typically the current frame time entering or leaving a given time
14591 An interval is specified by the following syntax:
14593 @var{START}[-@var{END}] @var{COMMANDS};
14596 The time interval is specified by the @var{START} and @var{END} times.
14597 @var{END} is optional and defaults to the maximum time.
14599 The current frame time is considered within the specified interval if
14600 it is included in the interval [@var{START}, @var{END}), that is when
14601 the time is greater or equal to @var{START} and is lesser than
14604 @var{COMMANDS} consists of a sequence of one or more command
14605 specifications, separated by ",", relating to that interval. The
14606 syntax of a command specification is given by:
14608 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
14611 @var{FLAGS} is optional and specifies the type of events relating to
14612 the time interval which enable sending the specified command, and must
14613 be a non-null sequence of identifier flags separated by "+" or "|" and
14614 enclosed between "[" and "]".
14616 The following flags are recognized:
14619 The command is sent when the current frame timestamp enters the
14620 specified interval. In other words, the command is sent when the
14621 previous frame timestamp was not in the given interval, and the
14625 The command is sent when the current frame timestamp leaves the
14626 specified interval. In other words, the command is sent when the
14627 previous frame timestamp was in the given interval, and the
14631 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
14634 @var{TARGET} specifies the target of the command, usually the name of
14635 the filter class or a specific filter instance name.
14637 @var{COMMAND} specifies the name of the command for the target filter.
14639 @var{ARG} is optional and specifies the optional list of argument for
14640 the given @var{COMMAND}.
14642 Between one interval specification and another, whitespaces, or
14643 sequences of characters starting with @code{#} until the end of line,
14644 are ignored and can be used to annotate comments.
14646 A simplified BNF description of the commands specification syntax
14649 @var{COMMAND_FLAG} ::= "enter" | "leave"
14650 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
14651 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
14652 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
14653 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
14654 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
14657 @subsection Examples
14661 Specify audio tempo change at second 4:
14663 asendcmd=c='4.0 atempo tempo 1.5',atempo
14667 Specify a list of drawtext and hue commands in a file.
14669 # show text in the interval 5-10
14670 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
14671 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
14673 # desaturate the image in the interval 15-20
14674 15.0-20.0 [enter] hue s 0,
14675 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
14677 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
14679 # apply an exponential saturation fade-out effect, starting from time 25
14680 25 [enter] hue s exp(25-t)
14683 A filtergraph allowing to read and process the above command list
14684 stored in a file @file{test.cmd}, can be specified with:
14686 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
14691 @section setpts, asetpts
14693 Change the PTS (presentation timestamp) of the input frames.
14695 @code{setpts} works on video frames, @code{asetpts} on audio frames.
14697 This filter accepts the following options:
14702 The expression which is evaluated for each frame to construct its timestamp.
14706 The expression is evaluated through the eval API and can contain the following
14711 frame rate, only defined for constant frame-rate video
14714 The presentation timestamp in input
14717 The count of the input frame for video or the number of consumed samples,
14718 not including the current frame for audio, starting from 0.
14720 @item NB_CONSUMED_SAMPLES
14721 The number of consumed samples, not including the current frame (only
14724 @item NB_SAMPLES, S
14725 The number of samples in the current frame (only audio)
14727 @item SAMPLE_RATE, SR
14728 The audio sample rate.
14731 The PTS of the first frame.
14734 the time in seconds of the first frame
14737 State whether the current frame is interlaced.
14740 the time in seconds of the current frame
14743 original position in the file of the frame, or undefined if undefined
14744 for the current frame
14747 The previous input PTS.
14750 previous input time in seconds
14753 The previous output PTS.
14756 previous output time in seconds
14759 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
14763 The wallclock (RTC) time at the start of the movie in microseconds.
14766 The timebase of the input timestamps.
14770 @subsection Examples
14774 Start counting PTS from zero
14776 setpts=PTS-STARTPTS
14780 Apply fast motion effect:
14786 Apply slow motion effect:
14792 Set fixed rate of 25 frames per second:
14798 Set fixed rate 25 fps with some jitter:
14800 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
14804 Apply an offset of 10 seconds to the input PTS:
14810 Generate timestamps from a "live source" and rebase onto the current timebase:
14812 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
14816 Generate timestamps by counting samples:
14823 @section settb, asettb
14825 Set the timebase to use for the output frames timestamps.
14826 It is mainly useful for testing timebase configuration.
14828 It accepts the following parameters:
14833 The expression which is evaluated into the output timebase.
14837 The value for @option{tb} is an arithmetic expression representing a
14838 rational. The expression can contain the constants "AVTB" (the default
14839 timebase), "intb" (the input timebase) and "sr" (the sample rate,
14840 audio only). Default value is "intb".
14842 @subsection Examples
14846 Set the timebase to 1/25:
14852 Set the timebase to 1/10:
14858 Set the timebase to 1001/1000:
14864 Set the timebase to 2*intb:
14870 Set the default timebase value:
14877 Convert input audio to a video output representing frequency spectrum
14878 logarithmically using Brown-Puckette constant Q transform algorithm with
14879 direct frequency domain coefficient calculation (but the transform itself
14880 is not really constant Q, instead the Q factor is actually variable/clamped),
14881 with musical tone scale, from E0 to D#10.
14883 The filter accepts the following options:
14887 Specify the video size for the output. It must be even. For the syntax of this option,
14888 check the @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14889 Default value is @code{1920x1080}.
14892 Set the output frame rate. Default value is @code{25}.
14895 Set the bargraph height. It must be even. Default value is @code{-1} which
14896 computes the bargraph height automatically.
14899 Set the axis height. It must be even. Default value is @code{-1} which computes
14900 the axis height automatically.
14903 Set the sonogram height. It must be even. Default value is @code{-1} which
14904 computes the sonogram height automatically.
14907 Set the fullhd resolution. This option is deprecated, use @var{size}, @var{s}
14908 instead. Default value is @code{1}.
14910 @item sono_v, volume
14911 Specify the sonogram volume expression. It can contain variables:
14914 the @var{bar_v} evaluated expression
14915 @item frequency, freq, f
14916 the frequency where it is evaluated
14917 @item timeclamp, tc
14918 the value of @var{timeclamp} option
14922 @item a_weighting(f)
14923 A-weighting of equal loudness
14924 @item b_weighting(f)
14925 B-weighting of equal loudness
14926 @item c_weighting(f)
14927 C-weighting of equal loudness.
14929 Default value is @code{16}.
14931 @item bar_v, volume2
14932 Specify the bargraph volume expression. It can contain variables:
14935 the @var{sono_v} evaluated expression
14936 @item frequency, freq, f
14937 the frequency where it is evaluated
14938 @item timeclamp, tc
14939 the value of @var{timeclamp} option
14943 @item a_weighting(f)
14944 A-weighting of equal loudness
14945 @item b_weighting(f)
14946 B-weighting of equal loudness
14947 @item c_weighting(f)
14948 C-weighting of equal loudness.
14950 Default value is @code{sono_v}.
14952 @item sono_g, gamma
14953 Specify the sonogram gamma. Lower gamma makes the spectrum more contrast,
14954 higher gamma makes the spectrum having more range. Default value is @code{3}.
14955 Acceptable range is @code{[1, 7]}.
14957 @item bar_g, gamma2
14958 Specify the bargraph gamma. Default value is @code{1}. Acceptable range is
14961 @item timeclamp, tc
14962 Specify the transform timeclamp. At low frequency, there is trade-off between
14963 accuracy in time domain and frequency domain. If timeclamp is lower,
14964 event in time domain is represented more accurately (such as fast bass drum),
14965 otherwise event in frequency domain is represented more accurately
14966 (such as bass guitar). Acceptable range is @code{[0.1, 1]}. Default value is @code{0.17}.
14969 Specify the transform base frequency. Default value is @code{20.01523126408007475},
14970 which is frequency 50 cents below E0. Acceptable range is @code{[10, 100000]}.
14973 Specify the transform end frequency. Default value is @code{20495.59681441799654},
14974 which is frequency 50 cents above D#10. Acceptable range is @code{[10, 100000]}.
14977 This option is deprecated and ignored.
14980 Specify the transform length in time domain. Use this option to control accuracy
14981 trade-off between time domain and frequency domain at every frequency sample.
14982 It can contain variables:
14984 @item frequency, freq, f
14985 the frequency where it is evaluated
14986 @item timeclamp, tc
14987 the value of @var{timeclamp} option.
14989 Default value is @code{384*tc/(384+tc*f)}.
14992 Specify the transform count for every video frame. Default value is @code{6}.
14993 Acceptable range is @code{[1, 30]}.
14996 Specify the transform count for every single pixel. Default value is @code{0},
14997 which makes it computed automatically. Acceptable range is @code{[0, 10]}.
15000 Specify font file for use with freetype to draw the axis. If not specified,
15001 use embedded font. Note that drawing with font file or embedded font is not
15002 implemented with custom @var{basefreq} and @var{endfreq}, use @var{axisfile}
15006 Specify font color expression. This is arithmetic expression that should return
15007 integer value 0xRRGGBB. It can contain variables:
15009 @item frequency, freq, f
15010 the frequency where it is evaluated
15011 @item timeclamp, tc
15012 the value of @var{timeclamp} option
15017 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
15018 @item r(x), g(x), b(x)
15019 red, green, and blue value of intensity x.
15021 Default value is @code{st(0, (midi(f)-59.5)/12);
15022 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
15023 r(1-ld(1)) + b(ld(1))}.
15026 Specify image file to draw the axis. This option override @var{fontfile} and
15027 @var{fontcolor} option.
15030 Enable/disable drawing text to the axis. If it is set to @code{0}, drawing to
15031 the axis is disabled, ignoring @var{fontfile} and @var{axisfile} option.
15032 Default value is @code{1}.
15036 @subsection Examples
15040 Playing audio while showing the spectrum:
15042 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
15046 Same as above, but with frame rate 30 fps:
15048 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
15052 Playing at 1280x720:
15054 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=s=1280x720:count=4 [out0]'
15058 Disable sonogram display:
15064 A1 and its harmonics: A1, A2, (near)E3, A3:
15066 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),
15067 asplit[a][out1]; [a] showcqt [out0]'
15071 Same as above, but with more accuracy in frequency domain:
15073 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),
15074 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
15080 bar_v=10:sono_v=bar_v*a_weighting(f)
15084 Custom gamma, now spectrum is linear to the amplitude.
15090 Custom tlength equation:
15092 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)))'
15096 Custom fontcolor and fontfile, C-note is colored green, others are colored blue:
15098 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))':fontfile=myfont.ttf
15102 Custom frequency range with custom axis using image file:
15104 axisfile=myaxis.png:basefreq=40:endfreq=10000
15110 Convert input audio to video output representing the audio power spectrum.
15111 Audio amplitude is on Y-axis while frequency is on X-axis.
15113 The filter accepts the following options:
15117 Specify size of video. For the syntax of this option, check the
15118 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15119 Default is @code{1024x512}.
15123 This set how each frequency bin will be represented.
15125 It accepts the following values:
15131 Default is @code{bar}.
15134 Set amplitude scale.
15136 It accepts the following values:
15150 Default is @code{log}.
15153 Set frequency scale.
15155 It accepts the following values:
15164 Reverse logarithmic scale.
15166 Default is @code{lin}.
15171 It accepts the following values:
15187 Default is @code{w2048}
15190 Set windowing function.
15192 It accepts the following values:
15210 Default is @code{hanning}.
15213 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
15214 which means optimal overlap for selected window function will be picked.
15217 Set time averaging. Setting this to 0 will display current maximal peaks.
15218 Default is @code{1}, which means time averaging is disabled.
15221 Specify list of colors separated by space or by '|' which will be used to
15222 draw channel frequencies. Unrecognized or missing colors will be replaced
15226 Set channel display mode.
15228 It accepts the following values:
15233 Default is @code{combined}.
15237 @anchor{showspectrum}
15238 @section showspectrum
15240 Convert input audio to a video output, representing the audio frequency
15243 The filter accepts the following options:
15247 Specify the video size for the output. For the syntax of this option, check the
15248 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15249 Default value is @code{640x512}.
15252 Specify how the spectrum should slide along the window.
15254 It accepts the following values:
15257 the samples start again on the left when they reach the right
15259 the samples scroll from right to left
15261 the samples scroll from left to right
15263 frames are only produced when the samples reach the right
15266 Default value is @code{replace}.
15269 Specify display mode.
15271 It accepts the following values:
15274 all channels are displayed in the same row
15276 all channels are displayed in separate rows
15279 Default value is @samp{combined}.
15282 Specify display color mode.
15284 It accepts the following values:
15287 each channel is displayed in a separate color
15289 each channel is displayed using the same color scheme
15291 each channel is displayed using the rainbow color scheme
15293 each channel is displayed using the moreland color scheme
15295 each channel is displayed using the nebulae color scheme
15297 each channel is displayed using the fire color scheme
15299 each channel is displayed using the fiery color scheme
15301 each channel is displayed using the fruit color scheme
15303 each channel is displayed using the cool color scheme
15306 Default value is @samp{channel}.
15309 Specify scale used for calculating intensity color values.
15311 It accepts the following values:
15316 square root, default
15327 Default value is @samp{sqrt}.
15330 Set saturation modifier for displayed colors. Negative values provide
15331 alternative color scheme. @code{0} is no saturation at all.
15332 Saturation must be in [-10.0, 10.0] range.
15333 Default value is @code{1}.
15336 Set window function.
15338 It accepts the following values:
15358 Default value is @code{hann}.
15361 Set orientation of time vs frequency axis. Can be @code{vertical} or
15362 @code{horizontal}. Default is @code{vertical}.
15365 Set ratio of overlap window. Default value is @code{0}.
15366 When value is @code{1} overlap is set to recommended size for specific
15367 window function currently used.
15370 Set scale gain for calculating intensity color values.
15371 Default value is @code{1}.
15374 Set which data to display. Can be @code{magnitude}, default or @code{phase}.
15377 The usage is very similar to the showwaves filter; see the examples in that
15380 @subsection Examples
15384 Large window with logarithmic color scaling:
15386 showspectrum=s=1280x480:scale=log
15390 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
15392 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
15393 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
15397 @section showspectrumpic
15399 Convert input audio to a single video frame, representing the audio frequency
15402 The filter accepts the following options:
15406 Specify the video size for the output. For the syntax of this option, check the
15407 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15408 Default value is @code{4096x2048}.
15411 Specify display mode.
15413 It accepts the following values:
15416 all channels are displayed in the same row
15418 all channels are displayed in separate rows
15420 Default value is @samp{combined}.
15423 Specify display color mode.
15425 It accepts the following values:
15428 each channel is displayed in a separate color
15430 each channel is displayed using the same color scheme
15432 each channel is displayed using the rainbow color scheme
15434 each channel is displayed using the moreland color scheme
15436 each channel is displayed using the nebulae color scheme
15438 each channel is displayed using the fire color scheme
15440 each channel is displayed using the fiery color scheme
15442 each channel is displayed using the fruit color scheme
15444 each channel is displayed using the cool color scheme
15446 Default value is @samp{intensity}.
15449 Specify scale used for calculating intensity color values.
15451 It accepts the following values:
15456 square root, default
15466 Default value is @samp{log}.
15469 Set saturation modifier for displayed colors. Negative values provide
15470 alternative color scheme. @code{0} is no saturation at all.
15471 Saturation must be in [-10.0, 10.0] range.
15472 Default value is @code{1}.
15475 Set window function.
15477 It accepts the following values:
15496 Default value is @code{hann}.
15499 Set orientation of time vs frequency axis. Can be @code{vertical} or
15500 @code{horizontal}. Default is @code{vertical}.
15503 Set scale gain for calculating intensity color values.
15504 Default value is @code{1}.
15507 Draw time and frequency axes and legends. Default is enabled.
15510 @subsection Examples
15514 Extract an audio spectrogram of a whole audio track
15515 in a 1024x1024 picture using @command{ffmpeg}:
15517 ffmpeg -i audio.flac -lavfi showspectrumpic=s=1024x1024 spectrogram.png
15521 @section showvolume
15523 Convert input audio volume to a video output.
15525 The filter accepts the following options:
15532 Set border width, allowed range is [0, 5]. Default is 1.
15535 Set channel width, allowed range is [80, 1080]. Default is 400.
15538 Set channel height, allowed range is [1, 100]. Default is 20.
15541 Set fade, allowed range is [0.001, 1]. Default is 0.95.
15544 Set volume color expression.
15546 The expression can use the following variables:
15550 Current max volume of channel in dB.
15553 Current channel number, starting from 0.
15557 If set, displays channel names. Default is enabled.
15560 If set, displays volume values. Default is enabled.
15565 Convert input audio to a video output, representing the samples waves.
15567 The filter accepts the following options:
15571 Specify the video size for the output. For the syntax of this option, check the
15572 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15573 Default value is @code{600x240}.
15578 Available values are:
15581 Draw a point for each sample.
15584 Draw a vertical line for each sample.
15587 Draw a point for each sample and a line between them.
15590 Draw a centered vertical line for each sample.
15593 Default value is @code{point}.
15596 Set the number of samples which are printed on the same column. A
15597 larger value will decrease the frame rate. Must be a positive
15598 integer. This option can be set only if the value for @var{rate}
15599 is not explicitly specified.
15602 Set the (approximate) output frame rate. This is done by setting the
15603 option @var{n}. Default value is "25".
15605 @item split_channels
15606 Set if channels should be drawn separately or overlap. Default value is 0.
15609 Set colors separated by '|' which are going to be used for drawing of each channel.
15612 Set amplitude scale. Can be linear @code{lin} or logarithmic @code{log}.
15617 @subsection Examples
15621 Output the input file audio and the corresponding video representation
15624 amovie=a.mp3,asplit[out0],showwaves[out1]
15628 Create a synthetic signal and show it with showwaves, forcing a
15629 frame rate of 30 frames per second:
15631 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
15635 @section showwavespic
15637 Convert input audio to a single video frame, representing the samples waves.
15639 The filter accepts the following options:
15643 Specify the video size for the output. For the syntax of this option, check the
15644 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15645 Default value is @code{600x240}.
15647 @item split_channels
15648 Set if channels should be drawn separately or overlap. Default value is 0.
15651 Set colors separated by '|' which are going to be used for drawing of each channel.
15654 Set amplitude scale. Can be linear @code{lin} or logarithmic @code{log}.
15658 @subsection Examples
15662 Extract a channel split representation of the wave form of a whole audio track
15663 in a 1024x800 picture using @command{ffmpeg}:
15665 ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png
15669 Colorize the waveform with colorchannelmixer. This example will make
15670 the waveform a green color approximately RGB(66,217,150). Additional
15671 channels will be shades of this color.
15673 ffmpeg -i audio.mp3 -filter_complex "showwavespic,colorchannelmixer=rr=66/255:gg=217/255:bb=150/255" waveform.png
15677 @section spectrumsynth
15679 Sythesize audio from 2 input video spectrums, first input stream represents
15680 magnitude across time and second represents phase across time.
15681 The filter will transform from frequency domain as displayed in videos back
15682 to time domain as presented in audio output.
15684 This filter is primarly created for reversing processed @ref{showspectrum}
15685 filter outputs, but can synthesize sound from other spectrograms too.
15686 But in such case results are going to be poor if the phase data is not
15687 available, because in such cases phase data need to be recreated, usually
15688 its just recreated from random noise.
15689 For best results use gray only output (@code{channel} color mode in
15690 @ref{showspectrum} filter) and @code{log} scale for magnitude video and
15691 @code{lin} scale for phase video. To produce phase, for 2nd video, use
15692 @code{data} option. Inputs videos should generally use @code{fullframe}
15693 slide mode as that saves resources needed for decoding video.
15695 The filter accepts the following options:
15699 Specify sample rate of output audio, the sample rate of audio from which
15700 spectrum was generated may differ.
15703 Set number of channels represented in input video spectrums.
15706 Set scale which was used when generating magnitude input spectrum.
15707 Can be @code{lin} or @code{log}. Default is @code{log}.
15710 Set slide which was used when generating inputs spectrums.
15711 Can be @code{replace}, @code{scroll}, @code{fullframe} or @code{rscroll}.
15712 Default is @code{fullframe}.
15715 Set window function used for resynthesis.
15718 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
15719 which means optimal overlap for selected window function will be picked.
15722 Set orientation of input videos. Can be @code{vertical} or @code{horizontal}.
15723 Default is @code{vertical}.
15726 @subsection Examples
15730 First create magnitude and phase videos from audio, assuming audio is stereo with 44100 sample rate,
15731 then resynthesize videos back to audio with spectrumsynth:
15733 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
15734 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
15735 ffmpeg -i magnitude.nut -i phase.nut -lavfi spectrumsynth=channels=2:sample_rate=44100:win_func=hann:overlap=0.875:slide=fullframe output.flac
15739 @section split, asplit
15741 Split input into several identical outputs.
15743 @code{asplit} works with audio input, @code{split} with video.
15745 The filter accepts a single parameter which specifies the number of outputs. If
15746 unspecified, it defaults to 2.
15748 @subsection Examples
15752 Create two separate outputs from the same input:
15754 [in] split [out0][out1]
15758 To create 3 or more outputs, you need to specify the number of
15761 [in] asplit=3 [out0][out1][out2]
15765 Create two separate outputs from the same input, one cropped and
15768 [in] split [splitout1][splitout2];
15769 [splitout1] crop=100:100:0:0 [cropout];
15770 [splitout2] pad=200:200:100:100 [padout];
15774 Create 5 copies of the input audio with @command{ffmpeg}:
15776 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
15782 Receive commands sent through a libzmq client, and forward them to
15783 filters in the filtergraph.
15785 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
15786 must be inserted between two video filters, @code{azmq} between two
15789 To enable these filters you need to install the libzmq library and
15790 headers and configure FFmpeg with @code{--enable-libzmq}.
15792 For more information about libzmq see:
15793 @url{http://www.zeromq.org/}
15795 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
15796 receives messages sent through a network interface defined by the
15797 @option{bind_address} option.
15799 The received message must be in the form:
15801 @var{TARGET} @var{COMMAND} [@var{ARG}]
15804 @var{TARGET} specifies the target of the command, usually the name of
15805 the filter class or a specific filter instance name.
15807 @var{COMMAND} specifies the name of the command for the target filter.
15809 @var{ARG} is optional and specifies the optional argument list for the
15810 given @var{COMMAND}.
15812 Upon reception, the message is processed and the corresponding command
15813 is injected into the filtergraph. Depending on the result, the filter
15814 will send a reply to the client, adopting the format:
15816 @var{ERROR_CODE} @var{ERROR_REASON}
15820 @var{MESSAGE} is optional.
15822 @subsection Examples
15824 Look at @file{tools/zmqsend} for an example of a zmq client which can
15825 be used to send commands processed by these filters.
15827 Consider the following filtergraph generated by @command{ffplay}
15829 ffplay -dumpgraph 1 -f lavfi "
15830 color=s=100x100:c=red [l];
15831 color=s=100x100:c=blue [r];
15832 nullsrc=s=200x100, zmq [bg];
15833 [bg][l] overlay [bg+l];
15834 [bg+l][r] overlay=x=100 "
15837 To change the color of the left side of the video, the following
15838 command can be used:
15840 echo Parsed_color_0 c yellow | tools/zmqsend
15843 To change the right side:
15845 echo Parsed_color_1 c pink | tools/zmqsend
15848 @c man end MULTIMEDIA FILTERS
15850 @chapter Multimedia Sources
15851 @c man begin MULTIMEDIA SOURCES
15853 Below is a description of the currently available multimedia sources.
15857 This is the same as @ref{movie} source, except it selects an audio
15863 Read audio and/or video stream(s) from a movie container.
15865 It accepts the following parameters:
15869 The name of the resource to read (not necessarily a file; it can also be a
15870 device or a stream accessed through some protocol).
15872 @item format_name, f
15873 Specifies the format assumed for the movie to read, and can be either
15874 the name of a container or an input device. If not specified, the
15875 format is guessed from @var{movie_name} or by probing.
15877 @item seek_point, sp
15878 Specifies the seek point in seconds. The frames will be output
15879 starting from this seek point. The parameter is evaluated with
15880 @code{av_strtod}, so the numerical value may be suffixed by an IS
15881 postfix. The default value is "0".
15884 Specifies the streams to read. Several streams can be specified,
15885 separated by "+". The source will then have as many outputs, in the
15886 same order. The syntax is explained in the ``Stream specifiers''
15887 section in the ffmpeg manual. Two special names, "dv" and "da" specify
15888 respectively the default (best suited) video and audio stream. Default
15889 is "dv", or "da" if the filter is called as "amovie".
15891 @item stream_index, si
15892 Specifies the index of the video stream to read. If the value is -1,
15893 the most suitable video stream will be automatically selected. The default
15894 value is "-1". Deprecated. If the filter is called "amovie", it will select
15895 audio instead of video.
15898 Specifies how many times to read the stream in sequence.
15899 If the value is less than 1, the stream will be read again and again.
15900 Default value is "1".
15902 Note that when the movie is looped the source timestamps are not
15903 changed, so it will generate non monotonically increasing timestamps.
15906 It allows overlaying a second video on top of the main input of
15907 a filtergraph, as shown in this graph:
15909 input -----------> deltapts0 --> overlay --> output
15912 movie --> scale--> deltapts1 -------+
15914 @subsection Examples
15918 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
15919 on top of the input labelled "in":
15921 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
15922 [in] setpts=PTS-STARTPTS [main];
15923 [main][over] overlay=16:16 [out]
15927 Read from a video4linux2 device, and overlay it on top of the input
15930 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
15931 [in] setpts=PTS-STARTPTS [main];
15932 [main][over] overlay=16:16 [out]
15936 Read the first video stream and the audio stream with id 0x81 from
15937 dvd.vob; the video is connected to the pad named "video" and the audio is
15938 connected to the pad named "audio":
15940 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
15944 @c man end MULTIMEDIA SOURCES