1 @chapter Filtering Introduction
2 @c man begin FILTERING INTRODUCTION
4 Filtering in FFmpeg is enabled through the libavfilter library.
6 In libavfilter, a filter can have multiple inputs and multiple
8 To illustrate the sorts of things that are possible, we consider the
13 input --> split ---------------------> overlay --> output
16 +-----> crop --> vflip -------+
19 This filtergraph splits the input stream in two streams, then sends one
20 stream through the crop filter and the vflip filter, before merging it
21 back with the other stream by overlaying it on top. You can use the
22 following command to achieve this:
25 ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
28 The result will be that the top half of the video is mirrored
29 onto the bottom half of the output video.
31 Filters in the same linear chain are separated by commas, and distinct
32 linear chains of filters are separated by semicolons. In our example,
33 @var{crop,vflip} are in one linear chain, @var{split} and
34 @var{overlay} are separately in another. The points where the linear
35 chains join are labelled by names enclosed in square brackets. In the
36 example, the split filter generates two outputs that are associated to
37 the labels @var{[main]} and @var{[tmp]}.
39 The stream sent to the second output of @var{split}, labelled as
40 @var{[tmp]}, is processed through the @var{crop} filter, which crops
41 away the lower half part of the video, and then vertically flipped. The
42 @var{overlay} filter takes in input the first unchanged output of the
43 split filter (which was labelled as @var{[main]}), and overlay on its
44 lower half the output generated by the @var{crop,vflip} filterchain.
46 Some filters take in input a list of parameters: they are specified
47 after the filter name and an equal sign, and are separated from each other
50 There exist so-called @var{source filters} that do not have an
51 audio/video input, and @var{sink filters} that will not have audio/video
54 @c man end FILTERING INTRODUCTION
57 @c man begin GRAPH2DOT
59 The @file{graph2dot} program included in the FFmpeg @file{tools}
60 directory can be used to parse a filtergraph description and issue a
61 corresponding textual representation in the dot language.
68 to see how to use @file{graph2dot}.
70 You can then pass the dot description to the @file{dot} program (from
71 the graphviz suite of programs) and obtain a graphical representation
74 For example the sequence of commands:
76 echo @var{GRAPH_DESCRIPTION} | \
77 tools/graph2dot -o graph.tmp && \
78 dot -Tpng graph.tmp -o graph.png && \
82 can be used to create and display an image representing the graph
83 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
84 a complete self-contained graph, with its inputs and outputs explicitly defined.
85 For example if your command line is of the form:
87 ffmpeg -i infile -vf scale=640:360 outfile
89 your @var{GRAPH_DESCRIPTION} string will need to be of the form:
91 nullsrc,scale=640:360,nullsink
93 you may also need to set the @var{nullsrc} parameters and add a @var{format}
94 filter in order to simulate a specific input file.
98 @chapter Filtergraph description
99 @c man begin FILTERGRAPH DESCRIPTION
101 A filtergraph is a directed graph of connected filters. It can contain
102 cycles, and there can be multiple links between a pair of
103 filters. Each link has one input pad on one side connecting it to one
104 filter from which it takes its input, and one output pad on the other
105 side connecting it to one filter accepting its output.
107 Each filter in a filtergraph is an instance of a filter class
108 registered in the application, which defines the features and the
109 number of input and output pads of the filter.
111 A filter with no input pads is called a "source", and a filter with no
112 output pads is called a "sink".
114 @anchor{Filtergraph syntax}
115 @section Filtergraph syntax
117 A filtergraph has a textual representation, which is recognized by the
118 @option{-filter}/@option{-vf}/@option{-af} and
119 @option{-filter_complex} options in @command{ffmpeg} and
120 @option{-vf}/@option{-af} in @command{ffplay}, and by the
121 @code{avfilter_graph_parse_ptr()} function defined in
122 @file{libavfilter/avfilter.h}.
124 A filterchain consists of a sequence of connected filters, each one
125 connected to the previous one in the sequence. A filterchain is
126 represented by a list of ","-separated filter descriptions.
128 A filtergraph consists of a sequence of filterchains. A sequence of
129 filterchains is represented by a list of ";"-separated filterchain
132 A filter is represented by a string of the form:
133 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
135 @var{filter_name} is the name of the filter class of which the
136 described filter is an instance of, and has to be the name of one of
137 the filter classes registered in the program.
138 The name of the filter class is optionally followed by a string
141 @var{arguments} is a string which contains the parameters used to
142 initialize the filter instance. It may have one of two forms:
146 A ':'-separated list of @var{key=value} pairs.
149 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
150 the option names in the order they are declared. E.g. the @code{fade} filter
151 declares three options in this order -- @option{type}, @option{start_frame} and
152 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
153 @var{in} is assigned to the option @option{type}, @var{0} to
154 @option{start_frame} and @var{30} to @option{nb_frames}.
157 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
158 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
159 follow the same constraints order of the previous point. The following
160 @var{key=value} pairs can be set in any preferred order.
164 If the option value itself is a list of items (e.g. the @code{format} filter
165 takes a list of pixel formats), the items in the list are usually separated by
168 The list of arguments can be quoted using the character @samp{'} as initial
169 and ending mark, and the character @samp{\} for escaping the characters
170 within the quoted text; otherwise the argument string is considered
171 terminated when the next special character (belonging to the set
172 @samp{[]=;,}) is encountered.
174 The name and arguments of the filter are optionally preceded and
175 followed by a list of link labels.
176 A link label allows one to name a link and associate it to a filter output
177 or input pad. The preceding labels @var{in_link_1}
178 ... @var{in_link_N}, are associated to the filter input pads,
179 the following labels @var{out_link_1} ... @var{out_link_M}, are
180 associated to the output pads.
182 When two link labels with the same name are found in the
183 filtergraph, a link between the corresponding input and output pad is
186 If an output pad is not labelled, it is linked by default to the first
187 unlabelled input pad of the next filter in the filterchain.
188 For example in the filterchain
190 nullsrc, split[L1], [L2]overlay, nullsink
192 the split filter instance has two output pads, and the overlay filter
193 instance two input pads. The first output pad of split is labelled
194 "L1", the first input pad of overlay is labelled "L2", and the second
195 output pad of split is linked to the second input pad of overlay,
196 which are both unlabelled.
198 In a filter description, if the input label of the first filter is not
199 specified, "in" is assumed; if the output label of the last filter is not
200 specified, "out" is assumed.
202 In a complete filterchain all the unlabelled filter input and output
203 pads must be connected. A filtergraph is considered valid if all the
204 filter input and output pads of all the filterchains are connected.
206 Libavfilter will automatically insert @ref{scale} filters where format
207 conversion is required. It is possible to specify swscale flags
208 for those automatically inserted scalers by prepending
209 @code{sws_flags=@var{flags};}
210 to the filtergraph description.
212 Here is a BNF description of the filtergraph syntax:
214 @var{NAME} ::= sequence of alphanumeric characters and '_'
215 @var{LINKLABEL} ::= "[" @var{NAME} "]"
216 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
217 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
218 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
219 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
220 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
223 @section Notes on filtergraph escaping
225 Filtergraph description composition entails several levels of
226 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
227 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
228 information about the employed escaping procedure.
230 A first level escaping affects the content of each filter option
231 value, which may contain the special character @code{:} used to
232 separate values, or one of the escaping characters @code{\'}.
234 A second level escaping affects the whole filter description, which
235 may contain the escaping characters @code{\'} or the special
236 characters @code{[],;} used by the filtergraph description.
238 Finally, when you specify a filtergraph on a shell commandline, you
239 need to perform a third level escaping for the shell special
240 characters contained within it.
242 For example, consider the following string to be embedded in
243 the @ref{drawtext} filter description @option{text} value:
245 this is a 'string': may contain one, or more, special characters
248 This string contains the @code{'} special escaping character, and the
249 @code{:} special character, so it needs to be escaped in this way:
251 text=this is a \'string\'\: may contain one, or more, special characters
254 A second level of escaping is required when embedding the filter
255 description in a filtergraph description, in order to escape all the
256 filtergraph special characters. Thus the example above becomes:
258 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
260 (note that in addition to the @code{\'} escaping special characters,
261 also @code{,} needs to be escaped).
263 Finally an additional level of escaping is needed when writing the
264 filtergraph description in a shell command, which depends on the
265 escaping rules of the adopted shell. For example, assuming that
266 @code{\} is special and needs to be escaped with another @code{\}, the
267 previous string will finally result in:
269 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
272 @chapter Timeline editing
274 Some filters support a generic @option{enable} option. For the filters
275 supporting timeline editing, this option can be set to an expression which is
276 evaluated before sending a frame to the filter. If the evaluation is non-zero,
277 the filter will be enabled, otherwise the frame will be sent unchanged to the
278 next filter in the filtergraph.
280 The expression accepts the following values:
283 timestamp expressed in seconds, NAN if the input timestamp is unknown
286 sequential number of the input frame, starting from 0
289 the position in the file of the input frame, NAN if unknown
293 width and height of the input frame if video
296 Additionally, these filters support an @option{enable} command that can be used
297 to re-define the expression.
299 Like any other filtering option, the @option{enable} option follows the same
302 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
303 minutes, and a @ref{curves} filter starting at 3 seconds:
305 smartblur = enable='between(t,10,3*60)',
306 curves = enable='gte(t,3)' : preset=cross_process
309 @c man end FILTERGRAPH DESCRIPTION
311 @chapter Audio Filters
312 @c man begin AUDIO FILTERS
314 When you configure your FFmpeg build, you can disable any of the
315 existing filters using @code{--disable-filters}.
316 The configure output will show the audio filters included in your
319 Below is a description of the currently available audio filters.
323 A compressor is mainly used to reduce the dynamic range of a signal.
324 Especially modern music is mostly compressed at a high ratio to
325 improve the overall loudness. It's done to get the highest attention
326 of a listener, "fatten" the sound and bring more "power" to the track.
327 If a signal is compressed too much it may sound dull or "dead"
328 afterwards or it may start to "pump" (which could be a powerful effect
329 but can also destroy a track completely).
330 The right compression is the key to reach a professional sound and is
331 the high art of mixing and mastering. Because of its complex settings
332 it may take a long time to get the right feeling for this kind of effect.
334 Compression is done by detecting the volume above a chosen level
335 @code{threshold} and dividing it by the factor set with @code{ratio}.
336 So if you set the threshold to -12dB and your signal reaches -6dB a ratio
337 of 2:1 will result in a signal at -9dB. Because an exact manipulation of
338 the signal would cause distortion of the waveform the reduction can be
339 levelled over the time. This is done by setting "Attack" and "Release".
340 @code{attack} determines how long the signal has to rise above the threshold
341 before any reduction will occur and @code{release} sets the time the signal
342 has to fall below the threshold to reduce the reduction again. Shorter signals
343 than the chosen attack time will be left untouched.
344 The overall reduction of the signal can be made up afterwards with the
345 @code{makeup} setting. So compressing the peaks of a signal about 6dB and
346 raising the makeup to this level results in a signal twice as loud than the
347 source. To gain a softer entry in the compression the @code{knee} flattens the
348 hard edge at the threshold in the range of the chosen decibels.
350 The filter accepts the following options:
354 Set input gain. Default is 1. Range is between 0.015625 and 64.
357 If a signal of second stream rises above this level it will affect the gain
358 reduction of the first stream.
359 By default it is 0.125. Range is between 0.00097563 and 1.
362 Set a ratio by which the signal is reduced. 1:2 means that if the level
363 rose 4dB above the threshold, it will be only 2dB above after the reduction.
364 Default is 2. Range is between 1 and 20.
367 Amount of milliseconds the signal has to rise above the threshold before gain
368 reduction starts. Default is 20. Range is between 0.01 and 2000.
371 Amount of milliseconds the signal has to fall below the threshold before
372 reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
375 Set the amount by how much signal will be amplified after processing.
376 Default is 2. Range is from 1 and 64.
379 Curve the sharp knee around the threshold to enter gain reduction more softly.
380 Default is 2.82843. Range is between 1 and 8.
383 Choose if the @code{average} level between all channels of input stream
384 or the louder(@code{maximum}) channel of input stream affects the
385 reduction. Default is @code{average}.
388 Should the exact signal be taken in case of @code{peak} or an RMS one in case
389 of @code{rms}. Default is @code{rms} which is mostly smoother.
392 How much to use compressed signal in output. Default is 1.
393 Range is between 0 and 1.
398 Apply cross fade from one input audio stream to another input audio stream.
399 The cross fade is applied for specified duration near the end of first stream.
401 The filter accepts the following options:
405 Specify the number of samples for which the cross fade effect has to last.
406 At the end of the cross fade effect the first input audio will be completely
407 silent. Default is 44100.
410 Specify the duration of the cross fade effect. See
411 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
412 for the accepted syntax.
413 By default the duration is determined by @var{nb_samples}.
414 If set this option is used instead of @var{nb_samples}.
417 Should first stream end overlap with second stream start. Default is enabled.
420 Set curve for cross fade transition for first stream.
423 Set curve for cross fade transition for second stream.
425 For description of available curve types see @ref{afade} filter description.
432 Cross fade from one input to another:
434 ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:c1=exp:c2=exp output.flac
438 Cross fade from one input to another but without overlapping:
440 ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:o=0:c1=exp:c2=exp output.flac
446 Delay one or more audio channels.
448 Samples in delayed channel are filled with silence.
450 The filter accepts the following option:
454 Set list of delays in milliseconds for each channel separated by '|'.
455 At least one delay greater than 0 should be provided.
456 Unused delays will be silently ignored. If number of given delays is
457 smaller than number of channels all remaining channels will not be delayed.
464 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
465 the second channel (and any other channels that may be present) unchanged.
473 Apply echoing to the input audio.
475 Echoes are reflected sound and can occur naturally amongst mountains
476 (and sometimes large buildings) when talking or shouting; digital echo
477 effects emulate this behaviour and are often used to help fill out the
478 sound of a single instrument or vocal. The time difference between the
479 original signal and the reflection is the @code{delay}, and the
480 loudness of the reflected signal is the @code{decay}.
481 Multiple echoes can have different delays and decays.
483 A description of the accepted parameters follows.
487 Set input gain of reflected signal. Default is @code{0.6}.
490 Set output gain of reflected signal. Default is @code{0.3}.
493 Set list of time intervals in milliseconds between original signal and reflections
494 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
495 Default is @code{1000}.
498 Set list of loudnesses of reflected signals separated by '|'.
499 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
500 Default is @code{0.5}.
507 Make it sound as if there are twice as many instruments as are actually playing:
509 aecho=0.8:0.88:60:0.4
513 If delay is very short, then it sound like a (metallic) robot playing music:
519 A longer delay will sound like an open air concert in the mountains:
521 aecho=0.8:0.9:1000:0.3
525 Same as above but with one more mountain:
527 aecho=0.8:0.9:1000|1800:0.3|0.25
532 Audio emphasis filter creates or restores material directly taken from LPs or
533 emphased CDs with different filter curves. E.g. to store music on vinyl the
534 signal has to be altered by a filter first to even out the disadvantages of
535 this recording medium.
536 Once the material is played back the inverse filter has to be applied to
537 restore the distortion of the frequency response.
539 The filter accepts the following options:
549 Set filter mode. For restoring material use @code{reproduction} mode, otherwise
550 use @code{production} mode. Default is @code{reproduction} mode.
553 Set filter type. Selects medium. Can be one of the following:
565 select Compact Disc (CD).
571 select 50µs (FM-KF).
573 select 75µs (FM-KF).
579 Modify an audio signal according to the specified expressions.
581 This filter accepts one or more expressions (one for each channel),
582 which are evaluated and used to modify a corresponding audio signal.
584 It accepts the following parameters:
588 Set the '|'-separated expressions list for each separate channel. If
589 the number of input channels is greater than the number of
590 expressions, the last specified expression is used for the remaining
593 @item channel_layout, c
594 Set output channel layout. If not specified, the channel layout is
595 specified by the number of expressions. If set to @samp{same}, it will
596 use by default the same input channel layout.
599 Each expression in @var{exprs} can contain the following constants and functions:
603 channel number of the current expression
606 number of the evaluated sample, starting from 0
612 time of the evaluated sample expressed in seconds
615 @item nb_out_channels
616 input and output number of channels
619 the value of input channel with number @var{CH}
622 Note: this filter is slow. For faster processing you should use a
631 aeval=val(ch)/2:c=same
635 Invert phase of the second channel:
644 Apply fade-in/out effect to input audio.
646 A description of the accepted parameters follows.
650 Specify the effect type, can be either @code{in} for fade-in, or
651 @code{out} for a fade-out effect. Default is @code{in}.
653 @item start_sample, ss
654 Specify the number of the start sample for starting to apply the fade
655 effect. Default is 0.
658 Specify the number of samples for which the fade effect has to last. At
659 the end of the fade-in effect the output audio will have the same
660 volume as the input audio, at the end of the fade-out transition
661 the output audio will be silence. Default is 44100.
664 Specify the start time of the fade effect. Default is 0.
665 The value must be specified as a time duration; see
666 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
667 for the accepted syntax.
668 If set this option is used instead of @var{start_sample}.
671 Specify the duration of the fade effect. See
672 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
673 for the accepted syntax.
674 At the end of the fade-in effect the output audio will have the same
675 volume as the input audio, at the end of the fade-out transition
676 the output audio will be silence.
677 By default the duration is determined by @var{nb_samples}.
678 If set this option is used instead of @var{nb_samples}.
681 Set curve for fade transition.
683 It accepts the following values:
686 select triangular, linear slope (default)
688 select quarter of sine wave
690 select half of sine wave
692 select exponential sine wave
696 select inverted parabola
710 select inverted quarter of sine wave
712 select inverted half of sine wave
714 select double-exponential seat
716 select double-exponential sigmoid
724 Fade in first 15 seconds of audio:
730 Fade out last 25 seconds of a 900 seconds audio:
732 afade=t=out:st=875:d=25
737 Apply arbitrary expressions to samples in frequency domain.
741 Set frequency domain real expression for each separate channel separated
742 by '|'. Default is "1".
743 If the number of input channels is greater than the number of
744 expressions, the last specified expression is used for the remaining
748 Set frequency domain imaginary expression for each separate channel
749 separated by '|'. If not set, @var{real} option is used.
751 Each expression in @var{real} and @var{imag} can contain the following
759 current frequency bin number
762 number of available bins
765 channel number of the current expression
777 It accepts the following values:
793 Default is @code{w4096}
796 Set window function. Default is @code{hann}.
799 Set window overlap. If set to 1, the recommended overlap for selected
800 window function will be picked. Default is @code{0.75}.
807 Leave almost only low frequencies in audio:
809 afftfilt="1-clip((b/nb)*b,0,1)"
816 Set output format constraints for the input audio. The framework will
817 negotiate the most appropriate format to minimize conversions.
819 It accepts the following parameters:
823 A '|'-separated list of requested sample formats.
826 A '|'-separated list of requested sample rates.
828 @item channel_layouts
829 A '|'-separated list of requested channel layouts.
831 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
832 for the required syntax.
835 If a parameter is omitted, all values are allowed.
837 Force the output to either unsigned 8-bit or signed 16-bit stereo
839 aformat=sample_fmts=u8|s16:channel_layouts=stereo
844 A gate is mainly used to reduce lower parts of a signal. This kind of signal
845 processing reduces disturbing noise between useful signals.
847 Gating is done by detecting the volume below a chosen level @var{threshold}
848 and divide it by the factor set with @var{ratio}. The bottom of the noise
849 floor is set via @var{range}. Because an exact manipulation of the signal
850 would cause distortion of the waveform the reduction can be levelled over
851 time. This is done by setting @var{attack} and @var{release}.
853 @var{attack} determines how long the signal has to fall below the threshold
854 before any reduction will occur and @var{release} sets the time the signal
855 has to raise above the threshold to reduce the reduction again.
856 Shorter signals than the chosen attack time will be left untouched.
860 Set input level before filtering.
861 Default is 1. Allowed range is from 0.015625 to 64.
864 Set the level of gain reduction when the signal is below the threshold.
865 Default is 0.06125. Allowed range is from 0 to 1.
868 If a signal rises above this level the gain reduction is released.
869 Default is 0.125. Allowed range is from 0 to 1.
872 Set a ratio about which the signal is reduced.
873 Default is 2. Allowed range is from 1 to 9000.
876 Amount of milliseconds the signal has to rise above the threshold before gain
878 Default is 20 milliseconds. Allowed range is from 0.01 to 9000.
881 Amount of milliseconds the signal has to fall below the threshold before the
882 reduction is increased again. Default is 250 milliseconds.
883 Allowed range is from 0.01 to 9000.
886 Set amount of amplification of signal after processing.
887 Default is 1. Allowed range is from 1 to 64.
890 Curve the sharp knee around the threshold to enter gain reduction more softly.
891 Default is 2.828427125. Allowed range is from 1 to 8.
894 Choose if exact signal should be taken for detection or an RMS like one.
895 Default is rms. Can be peak or rms.
898 Choose if the average level between all channels or the louder channel affects
900 Default is average. Can be average or maximum.
905 The limiter prevents input signal from raising over a desired threshold.
906 This limiter uses lookahead technology to prevent your signal from distorting.
907 It means that there is a small delay after signal is processed. Keep in mind
908 that the delay it produces is the attack time you set.
910 The filter accepts the following options:
914 Set input gain. Default is 1.
917 Set output gain. Default is 1.
920 Don't let signals above this level pass the limiter. Default is 1.
923 The limiter will reach its attenuation level in this amount of time in
924 milliseconds. Default is 5 milliseconds.
927 Come back from limiting to attenuation 1.0 in this amount of milliseconds.
928 Default is 50 milliseconds.
931 When gain reduction is always needed ASC takes care of releasing to an
932 average reduction level rather than reaching a reduction of 0 in the release
936 Select how much the release time is affected by ASC, 0 means nearly no changes
937 in release time while 1 produces higher release times.
940 Auto level output signal. Default is enabled.
941 This normalizes audio back to 0dB if enabled.
944 Depending on picked setting it is recommended to upsample input 2x or 4x times
945 with @ref{aresample} before applying this filter.
949 Apply a two-pole all-pass filter with central frequency (in Hz)
950 @var{frequency}, and filter-width @var{width}.
951 An all-pass filter changes the audio's frequency to phase relationship
952 without changing its frequency to amplitude relationship.
954 The filter accepts the following options:
961 Set method to specify band-width of filter.
974 Specify the band-width of a filter in width_type units.
980 Merge two or more audio streams into a single multi-channel stream.
982 The filter accepts the following options:
987 Set the number of inputs. Default is 2.
991 If the channel layouts of the inputs are disjoint, and therefore compatible,
992 the channel layout of the output will be set accordingly and the channels
993 will be reordered as necessary. If the channel layouts of the inputs are not
994 disjoint, the output will have all the channels of the first input then all
995 the channels of the second input, in that order, and the channel layout of
996 the output will be the default value corresponding to the total number of
999 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
1000 is FC+BL+BR, then the output will be in 5.1, with the channels in the
1001 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
1002 first input, b1 is the first channel of the second input).
1004 On the other hand, if both input are in stereo, the output channels will be
1005 in the default order: a1, a2, b1, b2, and the channel layout will be
1006 arbitrarily set to 4.0, which may or may not be the expected value.
1008 All inputs must have the same sample rate, and format.
1010 If inputs do not have the same duration, the output will stop with the
1013 @subsection Examples
1017 Merge two mono files into a stereo stream:
1019 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
1023 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
1025 ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv
1031 Mixes multiple audio inputs into a single output.
1033 Note that this filter only supports float samples (the @var{amerge}
1034 and @var{pan} audio filters support many formats). If the @var{amix}
1035 input has integer samples then @ref{aresample} will be automatically
1036 inserted to perform the conversion to float samples.
1040 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
1042 will mix 3 input audio streams to a single output with the same duration as the
1043 first input and a dropout transition time of 3 seconds.
1045 It accepts the following parameters:
1049 The number of inputs. If unspecified, it defaults to 2.
1052 How to determine the end-of-stream.
1056 The duration of the longest input. (default)
1059 The duration of the shortest input.
1062 The duration of the first input.
1066 @item dropout_transition
1067 The transition time, in seconds, for volume renormalization when an input
1068 stream ends. The default value is 2 seconds.
1072 @section anequalizer
1074 High-order parametric multiband equalizer for each channel.
1076 It accepts the following parameters:
1080 This option string is in format:
1081 "c@var{chn} f=@var{cf} w=@var{w} g=@var{g} t=@var{f} | ..."
1082 Each equalizer band is separated by '|'.
1086 Set channel number to which equalization will be applied.
1087 If input doesn't have that channel the entry is ignored.
1090 Set central frequency for band.
1091 If input doesn't have that frequency the entry is ignored.
1094 Set band width in hertz.
1097 Set band gain in dB.
1100 Set filter type for band, optional, can be:
1104 Butterworth, this is default.
1115 With this option activated frequency response of anequalizer is displayed
1119 Set video stream size. Only useful if curves option is activated.
1122 Set max gain that will be displayed. Only useful if curves option is activated.
1123 Setting this to reasonable value allows to display gain which is derived from
1124 neighbour bands which are too close to each other and thus produce higher gain
1125 when both are activated.
1128 Set frequency scale used to draw frequency response in video output.
1129 Can be linear or logarithmic. Default is logarithmic.
1132 Set color for each channel curve which is going to be displayed in video stream.
1133 This is list of color names separated by space or by '|'.
1134 Unrecognised or missing colors will be replaced by white color.
1137 @subsection Examples
1141 Lower gain by 10 of central frequency 200Hz and width 100 Hz
1142 for first 2 channels using Chebyshev type 1 filter:
1144 anequalizer=c0 f=200 w=100 g=-10 t=1|c1 f=200 w=100 g=-10 t=1
1148 @subsection Commands
1150 This filter supports the following commands:
1153 Alter existing filter parameters.
1154 Syntax for the commands is : "@var{fN}|f=@var{freq}|w=@var{width}|g=@var{gain}"
1156 @var{fN} is existing filter number, starting from 0, if no such filter is available
1158 @var{freq} set new frequency parameter.
1159 @var{width} set new width parameter in herz.
1160 @var{gain} set new gain parameter in dB.
1162 Full filter invocation with asendcmd may look like this:
1163 asendcmd=c='4.0 anequalizer change 0|f=200|w=50|g=1',anequalizer=...
1168 Pass the audio source unchanged to the output.
1172 Pad the end of an audio stream with silence.
1174 This can be used together with @command{ffmpeg} @option{-shortest} to
1175 extend audio streams to the same length as the video stream.
1177 A description of the accepted options follows.
1181 Set silence packet size. Default value is 4096.
1184 Set the number of samples of silence to add to the end. After the
1185 value is reached, the stream is terminated. This option is mutually
1186 exclusive with @option{whole_len}.
1189 Set the minimum total number of samples in the output audio stream. If
1190 the value is longer than the input audio length, silence is added to
1191 the end, until the value is reached. This option is mutually exclusive
1192 with @option{pad_len}.
1195 If neither the @option{pad_len} nor the @option{whole_len} option is
1196 set, the filter will add silence to the end of the input stream
1199 @subsection Examples
1203 Add 1024 samples of silence to the end of the input:
1209 Make sure the audio output will contain at least 10000 samples, pad
1210 the input with silence if required:
1212 apad=whole_len=10000
1216 Use @command{ffmpeg} to pad the audio input with silence, so that the
1217 video stream will always result the shortest and will be converted
1218 until the end in the output file when using the @option{shortest}
1221 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
1226 Add a phasing effect to the input audio.
1228 A phaser filter creates series of peaks and troughs in the frequency spectrum.
1229 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
1231 A description of the accepted parameters follows.
1235 Set input gain. Default is 0.4.
1238 Set output gain. Default is 0.74
1241 Set delay in milliseconds. Default is 3.0.
1244 Set decay. Default is 0.4.
1247 Set modulation speed in Hz. Default is 0.5.
1250 Set modulation type. Default is triangular.
1252 It accepts the following values:
1261 Audio pulsator is something between an autopanner and a tremolo.
1262 But it can produce funny stereo effects as well. Pulsator changes the volume
1263 of the left and right channel based on a LFO (low frequency oscillator) with
1264 different waveforms and shifted phases.
1265 This filter have the ability to define an offset between left and right
1266 channel. An offset of 0 means that both LFO shapes match each other.
1267 The left and right channel are altered equally - a conventional tremolo.
1268 An offset of 50% means that the shape of the right channel is exactly shifted
1269 in phase (or moved backwards about half of the frequency) - pulsator acts as
1270 an autopanner. At 1 both curves match again. Every setting in between moves the
1271 phase shift gapless between all stages and produces some "bypassing" sounds with
1272 sine and triangle waveforms. The more you set the offset near 1 (starting from
1273 the 0.5) the faster the signal passes from the left to the right speaker.
1275 The filter accepts the following options:
1279 Set input gain. By default it is 1. Range is [0.015625 - 64].
1282 Set output gain. By default it is 1. Range is [0.015625 - 64].
1285 Set waveform shape the LFO will use. Can be one of: sine, triangle, square,
1286 sawup or sawdown. Default is sine.
1289 Set modulation. Define how much of original signal is affected by the LFO.
1292 Set left channel offset. Default is 0. Allowed range is [0 - 1].
1295 Set right channel offset. Default is 0.5. Allowed range is [0 - 1].
1298 Set pulse width. Default is 1. Allowed range is [0 - 2].
1301 Set possible timing mode. Can be one of: bpm, ms or hz. Default is hz.
1304 Set bpm. Default is 120. Allowed range is [30 - 300]. Only used if timing
1308 Set ms. Default is 500. Allowed range is [10 - 2000]. Only used if timing
1312 Set frequency in Hz. Default is 2. Allowed range is [0.01 - 100]. Only used
1313 if timing is set to hz.
1319 Resample the input audio to the specified parameters, using the
1320 libswresample library. If none are specified then the filter will
1321 automatically convert between its input and output.
1323 This filter is also able to stretch/squeeze the audio data to make it match
1324 the timestamps or to inject silence / cut out audio to make it match the
1325 timestamps, do a combination of both or do neither.
1327 The filter accepts the syntax
1328 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
1329 expresses a sample rate and @var{resampler_options} is a list of
1330 @var{key}=@var{value} pairs, separated by ":". See the
1331 ffmpeg-resampler manual for the complete list of supported options.
1333 @subsection Examples
1337 Resample the input audio to 44100Hz:
1343 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
1344 samples per second compensation:
1346 aresample=async=1000
1350 @section asetnsamples
1352 Set the number of samples per each output audio frame.
1354 The last output packet may contain a different number of samples, as
1355 the filter will flush all the remaining samples when the input audio
1358 The filter accepts the following options:
1362 @item nb_out_samples, n
1363 Set the number of frames per each output audio frame. The number is
1364 intended as the number of samples @emph{per each channel}.
1365 Default value is 1024.
1368 If set to 1, the filter will pad the last audio frame with zeroes, so
1369 that the last frame will contain the same number of samples as the
1370 previous ones. Default value is 1.
1373 For example, to set the number of per-frame samples to 1234 and
1374 disable padding for the last frame, use:
1376 asetnsamples=n=1234:p=0
1381 Set the sample rate without altering the PCM data.
1382 This will result in a change of speed and pitch.
1384 The filter accepts the following options:
1387 @item sample_rate, r
1388 Set the output sample rate. Default is 44100 Hz.
1393 Show a line containing various information for each input audio frame.
1394 The input audio is not modified.
1396 The shown line contains a sequence of key/value pairs of the form
1397 @var{key}:@var{value}.
1399 The following values are shown in the output:
1403 The (sequential) number of the input frame, starting from 0.
1406 The presentation timestamp of the input frame, in time base units; the time base
1407 depends on the filter input pad, and is usually 1/@var{sample_rate}.
1410 The presentation timestamp of the input frame in seconds.
1413 position of the frame in the input stream, -1 if this information in
1414 unavailable and/or meaningless (for example in case of synthetic audio)
1423 The sample rate for the audio frame.
1426 The number of samples (per channel) in the frame.
1429 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
1430 audio, the data is treated as if all the planes were concatenated.
1432 @item plane_checksums
1433 A list of Adler-32 checksums for each data plane.
1439 Display time domain statistical information about the audio channels.
1440 Statistics are calculated and displayed for each audio channel and,
1441 where applicable, an overall figure is also given.
1443 It accepts the following option:
1446 Short window length in seconds, used for peak and trough RMS measurement.
1447 Default is @code{0.05} (50 milliseconds). Allowed range is @code{[0.1 - 10]}.
1451 Set metadata injection. All the metadata keys are prefixed with @code{lavfi.astats.X},
1452 where @code{X} is channel number starting from 1 or string @code{Overall}. Default is
1455 Available keys for each channel are:
1486 For example full key look like this @code{lavfi.astats.1.DC_offset} or
1487 this @code{lavfi.astats.Overall.Peak_count}.
1489 For description what each key means read below.
1492 Set number of frame after which stats are going to be recalculated.
1493 Default is disabled.
1496 A description of each shown parameter follows:
1500 Mean amplitude displacement from zero.
1503 Minimal sample level.
1506 Maximal sample level.
1508 @item Min difference
1509 Minimal difference between two consecutive samples.
1511 @item Max difference
1512 Maximal difference between two consecutive samples.
1514 @item Mean difference
1515 Mean difference between two consecutive samples.
1516 The average of each difference between two consecutive samples.
1520 Standard peak and RMS level measured in dBFS.
1524 Peak and trough values for RMS level measured over a short window.
1527 Standard ratio of peak to RMS level (note: not in dB).
1530 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
1531 (i.e. either @var{Min level} or @var{Max level}).
1534 Number of occasions (not the number of samples) that the signal attained either
1535 @var{Min level} or @var{Max level}.
1538 Overall bit depth of audio. Number of bits used for each sample.
1543 Synchronize audio data with timestamps by squeezing/stretching it and/or
1544 dropping samples/adding silence when needed.
1546 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1548 It accepts the following parameters:
1552 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1553 by default. When disabled, time gaps are covered with silence.
1556 The minimum difference between timestamps and audio data (in seconds) to trigger
1557 adding/dropping samples. The default value is 0.1. If you get an imperfect
1558 sync with this filter, try setting this parameter to 0.
1561 The maximum compensation in samples per second. Only relevant with compensate=1.
1562 The default value is 500.
1565 Assume that the first PTS should be this value. The time base is 1 / sample
1566 rate. This allows for padding/trimming at the start of the stream. By default,
1567 no assumption is made about the first frame's expected PTS, so no padding or
1568 trimming is done. For example, this could be set to 0 to pad the beginning with
1569 silence if an audio stream starts after the video stream or to trim any samples
1570 with a negative PTS due to encoder delay.
1578 The filter accepts exactly one parameter, the audio tempo. If not
1579 specified then the filter will assume nominal 1.0 tempo. Tempo must
1580 be in the [0.5, 2.0] range.
1582 @subsection Examples
1586 Slow down audio to 80% tempo:
1592 To speed up audio to 125% tempo:
1600 Trim the input so that the output contains one continuous subpart of the input.
1602 It accepts the following parameters:
1605 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1606 sample with the timestamp @var{start} will be the first sample in the output.
1609 Specify time of the first audio sample that will be dropped, i.e. the
1610 audio sample immediately preceding the one with the timestamp @var{end} will be
1611 the last sample in the output.
1614 Same as @var{start}, except this option sets the start timestamp in samples
1618 Same as @var{end}, except this option sets the end timestamp in samples instead
1622 The maximum duration of the output in seconds.
1625 The number of the first sample that should be output.
1628 The number of the first sample that should be dropped.
1631 @option{start}, @option{end}, and @option{duration} are expressed as time
1632 duration specifications; see
1633 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
1635 Note that the first two sets of the start/end options and the @option{duration}
1636 option look at the frame timestamp, while the _sample options simply count the
1637 samples that pass through the filter. So start/end_pts and start/end_sample will
1638 give different results when the timestamps are wrong, inexact or do not start at
1639 zero. Also note that this filter does not modify the timestamps. If you wish
1640 to have the output timestamps start at zero, insert the asetpts filter after the
1643 If multiple start or end options are set, this filter tries to be greedy and
1644 keep all samples that match at least one of the specified constraints. To keep
1645 only the part that matches all the constraints at once, chain multiple atrim
1648 The defaults are such that all the input is kept. So it is possible to set e.g.
1649 just the end values to keep everything before the specified time.
1654 Drop everything except the second minute of input:
1656 ffmpeg -i INPUT -af atrim=60:120
1660 Keep only the first 1000 samples:
1662 ffmpeg -i INPUT -af atrim=end_sample=1000
1669 Apply a two-pole Butterworth band-pass filter with central
1670 frequency @var{frequency}, and (3dB-point) band-width width.
1671 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1672 instead of the default: constant 0dB peak gain.
1673 The filter roll off at 6dB per octave (20dB per decade).
1675 The filter accepts the following options:
1679 Set the filter's central frequency. Default is @code{3000}.
1682 Constant skirt gain if set to 1. Defaults to 0.
1685 Set method to specify band-width of filter.
1698 Specify the band-width of a filter in width_type units.
1703 Apply a two-pole Butterworth band-reject filter with central
1704 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1705 The filter roll off at 6dB per octave (20dB per decade).
1707 The filter accepts the following options:
1711 Set the filter's central frequency. Default is @code{3000}.
1714 Set method to specify band-width of filter.
1727 Specify the band-width of a filter in width_type units.
1732 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1733 shelving filter with a response similar to that of a standard
1734 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1736 The filter accepts the following options:
1740 Give the gain at 0 Hz. Its useful range is about -20
1741 (for a large cut) to +20 (for a large boost).
1742 Beware of clipping when using a positive gain.
1745 Set the filter's central frequency and so can be used
1746 to extend or reduce the frequency range to be boosted or cut.
1747 The default value is @code{100} Hz.
1750 Set method to specify band-width of filter.
1763 Determine how steep is the filter's shelf transition.
1768 Apply a biquad IIR filter with the given coefficients.
1769 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1770 are the numerator and denominator coefficients respectively.
1773 Bauer stereo to binaural transformation, which improves headphone listening of
1774 stereo audio records.
1776 It accepts the following parameters:
1780 Pre-defined crossfeed level.
1784 Default level (fcut=700, feed=50).
1787 Chu Moy circuit (fcut=700, feed=60).
1790 Jan Meier circuit (fcut=650, feed=95).
1795 Cut frequency (in Hz).
1804 Remap input channels to new locations.
1806 It accepts the following parameters:
1808 @item channel_layout
1809 The channel layout of the output stream.
1812 Map channels from input to output. The argument is a '|'-separated list of
1813 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1814 @var{in_channel} form. @var{in_channel} can be either the name of the input
1815 channel (e.g. FL for front left) or its index in the input channel layout.
1816 @var{out_channel} is the name of the output channel or its index in the output
1817 channel layout. If @var{out_channel} is not given then it is implicitly an
1818 index, starting with zero and increasing by one for each mapping.
1821 If no mapping is present, the filter will implicitly map input channels to
1822 output channels, preserving indices.
1824 For example, assuming a 5.1+downmix input MOV file,
1826 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1828 will create an output WAV file tagged as stereo from the downmix channels of
1831 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1833 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:5.1' out.wav
1836 @section channelsplit
1838 Split each channel from an input audio stream into a separate output stream.
1840 It accepts the following parameters:
1842 @item channel_layout
1843 The channel layout of the input stream. The default is "stereo".
1846 For example, assuming a stereo input MP3 file,
1848 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1850 will create an output Matroska file with two audio streams, one containing only
1851 the left channel and the other the right channel.
1853 Split a 5.1 WAV file into per-channel files:
1855 ffmpeg -i in.wav -filter_complex
1856 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1857 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1858 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1863 Add a chorus effect to the audio.
1865 Can make a single vocal sound like a chorus, but can also be applied to instrumentation.
1867 Chorus resembles an echo effect with a short delay, but whereas with echo the delay is
1868 constant, with chorus, it is varied using using sinusoidal or triangular modulation.
1869 The modulation depth defines the range the modulated delay is played before or after
1870 the delay. Hence the delayed sound will sound slower or faster, that is the delayed
1871 sound tuned around the original one, like in a chorus where some vocals are slightly
1874 It accepts the following parameters:
1877 Set input gain. Default is 0.4.
1880 Set output gain. Default is 0.4.
1883 Set delays. A typical delay is around 40ms to 60ms.
1895 @subsection Examples
1901 chorus=0.7:0.9:55:0.4:0.25:2
1907 chorus=0.6:0.9:50|60:0.4|0.32:0.25|0.4:2|1.3
1911 Fuller sounding chorus with three delays:
1913 chorus=0.5:0.9:50|60|40:0.4|0.32|0.3:0.25|0.4|0.3:2|2.3|1.3
1918 Compress or expand the audio's dynamic range.
1920 It accepts the following parameters:
1926 A list of times in seconds for each channel over which the instantaneous level
1927 of the input signal is averaged to determine its volume. @var{attacks} refers to
1928 increase of volume and @var{decays} refers to decrease of volume. For most
1929 situations, the attack time (response to the audio getting louder) should be
1930 shorter than the decay time, because the human ear is more sensitive to sudden
1931 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1932 a typical value for decay is 0.8 seconds.
1933 If specified number of attacks & decays is lower than number of channels, the last
1934 set attack/decay will be used for all remaining channels.
1937 A list of points for the transfer function, specified in dB relative to the
1938 maximum possible signal amplitude. Each key points list must be defined using
1939 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1940 @code{x0/y0 x1/y1 x2/y2 ....}
1942 The input values must be in strictly increasing order but the transfer function
1943 does not have to be monotonically rising. The point @code{0/0} is assumed but
1944 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1945 function are @code{-70/-70|-60/-20}.
1948 Set the curve radius in dB for all joints. It defaults to 0.01.
1951 Set the additional gain in dB to be applied at all points on the transfer
1952 function. This allows for easy adjustment of the overall gain.
1956 Set an initial volume, in dB, to be assumed for each channel when filtering
1957 starts. This permits the user to supply a nominal level initially, so that, for
1958 example, a very large gain is not applied to initial signal levels before the
1959 companding has begun to operate. A typical value for audio which is initially
1960 quiet is -90 dB. It defaults to 0.
1963 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1964 delayed before being fed to the volume adjuster. Specifying a delay
1965 approximately equal to the attack/decay times allows the filter to effectively
1966 operate in predictive rather than reactive mode. It defaults to 0.
1970 @subsection Examples
1974 Make music with both quiet and loud passages suitable for listening to in a
1977 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1980 Another example for audio with whisper and explosion parts:
1982 compand=0|0:1|1:-90/-900|-70/-70|-30/-9|0/-3:6:0:0:0
1986 A noise gate for when the noise is at a lower level than the signal:
1988 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1992 Here is another noise gate, this time for when the noise is at a higher level
1993 than the signal (making it, in some ways, similar to squelch):
1995 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1999 2:1 compression starting at -6dB:
2001 compand=points=-80/-80|-6/-6|0/-3.8|20/3.5
2005 2:1 compression starting at -9dB:
2007 compand=points=-80/-80|-9/-9|0/-5.3|20/2.9
2011 2:1 compression starting at -12dB:
2013 compand=points=-80/-80|-12/-12|0/-6.8|20/1.9
2017 2:1 compression starting at -18dB:
2019 compand=points=-80/-80|-18/-18|0/-9.8|20/0.7
2023 3:1 compression starting at -15dB:
2025 compand=points=-80/-80|-15/-15|0/-10.8|20/-5.2
2031 compand=points=-80/-105|-62/-80|-15.4/-15.4|0/-12|20/-7.6
2037 compand=attacks=0:points=-80/-169|-54/-80|-49.5/-64.6|-41.1/-41.1|-25.8/-15|-10.8/-4.5|0/0|20/8.3
2041 Hard limiter at -6dB:
2043 compand=attacks=0:points=-80/-80|-6/-6|20/-6
2047 Hard limiter at -12dB:
2049 compand=attacks=0:points=-80/-80|-12/-12|20/-12
2053 Hard noise gate at -35 dB:
2055 compand=attacks=0:points=-80/-115|-35.1/-80|-35/-35|20/20
2061 compand=attacks=0:points=-80/-80|-12.4/-12.4|-6/-8|0/-6.8|20/-2.8
2065 @section compensationdelay
2067 Compensation Delay Line is a metric based delay to compensate differing
2068 positions of microphones or speakers.
2070 For example, you have recorded guitar with two microphones placed in
2071 different location. Because the front of sound wave has fixed speed in
2072 normal conditions, the phasing of microphones can vary and depends on
2073 their location and interposition. The best sound mix can be achieved when
2074 these microphones are in phase (synchronized). Note that distance of
2075 ~30 cm between microphones makes one microphone to capture signal in
2076 antiphase to another microphone. That makes the final mix sounding moody.
2077 This filter helps to solve phasing problems by adding different delays
2078 to each microphone track and make them synchronized.
2080 The best result can be reached when you take one track as base and
2081 synchronize other tracks one by one with it.
2082 Remember that synchronization/delay tolerance depends on sample rate, too.
2083 Higher sample rates will give more tolerance.
2085 It accepts the following parameters:
2089 Set millimeters distance. This is compensation distance for fine tuning.
2093 Set cm distance. This is compensation distance for tightening distance setup.
2097 Set meters distance. This is compensation distance for hard distance setup.
2101 Set dry amount. Amount of unprocessed (dry) signal.
2105 Set wet amount. Amount of processed (wet) signal.
2109 Set temperature degree in Celsius. This is the temperature of the environment.
2114 Apply a DC shift to the audio.
2116 This can be useful to remove a DC offset (caused perhaps by a hardware problem
2117 in the recording chain) from the audio. The effect of a DC offset is reduced
2118 headroom and hence volume. The @ref{astats} filter can be used to determine if
2119 a signal has a DC offset.
2123 Set the DC shift, allowed range is [-1, 1]. It indicates the amount to shift
2127 Optional. It should have a value much less than 1 (e.g. 0.05 or 0.02) and is
2128 used to prevent clipping.
2132 Dynamic Audio Normalizer.
2134 This filter applies a certain amount of gain to the input audio in order
2135 to bring its peak magnitude to a target level (e.g. 0 dBFS). However, in
2136 contrast to more "simple" normalization algorithms, the Dynamic Audio
2137 Normalizer *dynamically* re-adjusts the gain factor to the input audio.
2138 This allows for applying extra gain to the "quiet" sections of the audio
2139 while avoiding distortions or clipping the "loud" sections. In other words:
2140 The Dynamic Audio Normalizer will "even out" the volume of quiet and loud
2141 sections, in the sense that the volume of each section is brought to the
2142 same target level. Note, however, that the Dynamic Audio Normalizer achieves
2143 this goal *without* applying "dynamic range compressing". It will retain 100%
2144 of the dynamic range *within* each section of the audio file.
2148 Set the frame length in milliseconds. In range from 10 to 8000 milliseconds.
2149 Default is 500 milliseconds.
2150 The Dynamic Audio Normalizer processes the input audio in small chunks,
2151 referred to as frames. This is required, because a peak magnitude has no
2152 meaning for just a single sample value. Instead, we need to determine the
2153 peak magnitude for a contiguous sequence of sample values. While a "standard"
2154 normalizer would simply use the peak magnitude of the complete file, the
2155 Dynamic Audio Normalizer determines the peak magnitude individually for each
2156 frame. The length of a frame is specified in milliseconds. By default, the
2157 Dynamic Audio Normalizer uses a frame length of 500 milliseconds, which has
2158 been found to give good results with most files.
2159 Note that the exact frame length, in number of samples, will be determined
2160 automatically, based on the sampling rate of the individual input audio file.
2163 Set the Gaussian filter window size. In range from 3 to 301, must be odd
2164 number. Default is 31.
2165 Probably the most important parameter of the Dynamic Audio Normalizer is the
2166 @code{window size} of the Gaussian smoothing filter. The filter's window size
2167 is specified in frames, centered around the current frame. For the sake of
2168 simplicity, this must be an odd number. Consequently, the default value of 31
2169 takes into account the current frame, as well as the 15 preceding frames and
2170 the 15 subsequent frames. Using a larger window results in a stronger
2171 smoothing effect and thus in less gain variation, i.e. slower gain
2172 adaptation. Conversely, using a smaller window results in a weaker smoothing
2173 effect and thus in more gain variation, i.e. faster gain adaptation.
2174 In other words, the more you increase this value, the more the Dynamic Audio
2175 Normalizer will behave like a "traditional" normalization filter. On the
2176 contrary, the more you decrease this value, the more the Dynamic Audio
2177 Normalizer will behave like a dynamic range compressor.
2180 Set the target peak value. This specifies the highest permissible magnitude
2181 level for the normalized audio input. This filter will try to approach the
2182 target peak magnitude as closely as possible, but at the same time it also
2183 makes sure that the normalized signal will never exceed the peak magnitude.
2184 A frame's maximum local gain factor is imposed directly by the target peak
2185 magnitude. The default value is 0.95 and thus leaves a headroom of 5%*.
2186 It is not recommended to go above this value.
2189 Set the maximum gain factor. In range from 1.0 to 100.0. Default is 10.0.
2190 The Dynamic Audio Normalizer determines the maximum possible (local) gain
2191 factor for each input frame, i.e. the maximum gain factor that does not
2192 result in clipping or distortion. The maximum gain factor is determined by
2193 the frame's highest magnitude sample. However, the Dynamic Audio Normalizer
2194 additionally bounds the frame's maximum gain factor by a predetermined
2195 (global) maximum gain factor. This is done in order to avoid excessive gain
2196 factors in "silent" or almost silent frames. By default, the maximum gain
2197 factor is 10.0, For most inputs the default value should be sufficient and
2198 it usually is not recommended to increase this value. Though, for input
2199 with an extremely low overall volume level, it may be necessary to allow even
2200 higher gain factors. Note, however, that the Dynamic Audio Normalizer does
2201 not simply apply a "hard" threshold (i.e. cut off values above the threshold).
2202 Instead, a "sigmoid" threshold function will be applied. This way, the
2203 gain factors will smoothly approach the threshold value, but never exceed that
2207 Set the target RMS. In range from 0.0 to 1.0. Default is 0.0 - disabled.
2208 By default, the Dynamic Audio Normalizer performs "peak" normalization.
2209 This means that the maximum local gain factor for each frame is defined
2210 (only) by the frame's highest magnitude sample. This way, the samples can
2211 be amplified as much as possible without exceeding the maximum signal
2212 level, i.e. without clipping. Optionally, however, the Dynamic Audio
2213 Normalizer can also take into account the frame's root mean square,
2214 abbreviated RMS. In electrical engineering, the RMS is commonly used to
2215 determine the power of a time-varying signal. It is therefore considered
2216 that the RMS is a better approximation of the "perceived loudness" than
2217 just looking at the signal's peak magnitude. Consequently, by adjusting all
2218 frames to a constant RMS value, a uniform "perceived loudness" can be
2219 established. If a target RMS value has been specified, a frame's local gain
2220 factor is defined as the factor that would result in exactly that RMS value.
2221 Note, however, that the maximum local gain factor is still restricted by the
2222 frame's highest magnitude sample, in order to prevent clipping.
2225 Enable channels coupling. By default is enabled.
2226 By default, the Dynamic Audio Normalizer will amplify all channels by the same
2227 amount. This means the same gain factor will be applied to all channels, i.e.
2228 the maximum possible gain factor is determined by the "loudest" channel.
2229 However, in some recordings, it may happen that the volume of the different
2230 channels is uneven, e.g. one channel may be "quieter" than the other one(s).
2231 In this case, this option can be used to disable the channel coupling. This way,
2232 the gain factor will be determined independently for each channel, depending
2233 only on the individual channel's highest magnitude sample. This allows for
2234 harmonizing the volume of the different channels.
2237 Enable DC bias correction. By default is disabled.
2238 An audio signal (in the time domain) is a sequence of sample values.
2239 In the Dynamic Audio Normalizer these sample values are represented in the
2240 -1.0 to 1.0 range, regardless of the original input format. Normally, the
2241 audio signal, or "waveform", should be centered around the zero point.
2242 That means if we calculate the mean value of all samples in a file, or in a
2243 single frame, then the result should be 0.0 or at least very close to that
2244 value. If, however, there is a significant deviation of the mean value from
2245 0.0, in either positive or negative direction, this is referred to as a
2246 DC bias or DC offset. Since a DC bias is clearly undesirable, the Dynamic
2247 Audio Normalizer provides optional DC bias correction.
2248 With DC bias correction enabled, the Dynamic Audio Normalizer will determine
2249 the mean value, or "DC correction" offset, of each input frame and subtract
2250 that value from all of the frame's sample values which ensures those samples
2251 are centered around 0.0 again. Also, in order to avoid "gaps" at the frame
2252 boundaries, the DC correction offset values will be interpolated smoothly
2253 between neighbouring frames.
2256 Enable alternative boundary mode. By default is disabled.
2257 The Dynamic Audio Normalizer takes into account a certain neighbourhood
2258 around each frame. This includes the preceding frames as well as the
2259 subsequent frames. However, for the "boundary" frames, located at the very
2260 beginning and at the very end of the audio file, not all neighbouring
2261 frames are available. In particular, for the first few frames in the audio
2262 file, the preceding frames are not known. And, similarly, for the last few
2263 frames in the audio file, the subsequent frames are not known. Thus, the
2264 question arises which gain factors should be assumed for the missing frames
2265 in the "boundary" region. The Dynamic Audio Normalizer implements two modes
2266 to deal with this situation. The default boundary mode assumes a gain factor
2267 of exactly 1.0 for the missing frames, resulting in a smooth "fade in" and
2268 "fade out" at the beginning and at the end of the input, respectively.
2271 Set the compress factor. In range from 0.0 to 30.0. Default is 0.0.
2272 By default, the Dynamic Audio Normalizer does not apply "traditional"
2273 compression. This means that signal peaks will not be pruned and thus the
2274 full dynamic range will be retained within each local neighbourhood. However,
2275 in some cases it may be desirable to combine the Dynamic Audio Normalizer's
2276 normalization algorithm with a more "traditional" compression.
2277 For this purpose, the Dynamic Audio Normalizer provides an optional compression
2278 (thresholding) function. If (and only if) the compression feature is enabled,
2279 all input frames will be processed by a soft knee thresholding function prior
2280 to the actual normalization process. Put simply, the thresholding function is
2281 going to prune all samples whose magnitude exceeds a certain threshold value.
2282 However, the Dynamic Audio Normalizer does not simply apply a fixed threshold
2283 value. Instead, the threshold value will be adjusted for each individual
2285 In general, smaller parameters result in stronger compression, and vice versa.
2286 Values below 3.0 are not recommended, because audible distortion may appear.
2291 Make audio easier to listen to on headphones.
2293 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
2294 so that when listened to on headphones the stereo image is moved from
2295 inside your head (standard for headphones) to outside and in front of
2296 the listener (standard for speakers).
2302 Apply a two-pole peaking equalisation (EQ) filter. With this
2303 filter, the signal-level at and around a selected frequency can
2304 be increased or decreased, whilst (unlike bandpass and bandreject
2305 filters) that at all other frequencies is unchanged.
2307 In order to produce complex equalisation curves, this filter can
2308 be given several times, each with a different central frequency.
2310 The filter accepts the following options:
2314 Set the filter's central frequency in Hz.
2317 Set method to specify band-width of filter.
2330 Specify the band-width of a filter in width_type units.
2333 Set the required gain or attenuation in dB.
2334 Beware of clipping when using a positive gain.
2337 @subsection Examples
2340 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
2342 equalizer=f=1000:width_type=h:width=200:g=-10
2346 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
2348 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
2352 @section extrastereo
2354 Linearly increases the difference between left and right channels which
2355 adds some sort of "live" effect to playback.
2357 The filter accepts the following option:
2361 Sets the difference coefficient (default: 2.5). 0.0 means mono sound
2362 (average of both channels), with 1.0 sound will be unchanged, with
2363 -1.0 left and right channels will be swapped.
2366 Enable clipping. By default is enabled.
2369 @section firequalizer
2370 Apply FIR Equalization using arbitrary frequency response.
2372 The filter accepts the following option:
2376 Set gain curve equation (in dB). The expression can contain variables:
2379 the evaluated frequency
2383 channel number, set to 0 when multichannels evaluation is disabled
2385 channel id, see libavutil/channel_layout.h, set to the first channel id when
2386 multichannels evaluation is disabled
2390 channel_layout, see libavutil/channel_layout.h
2395 @item gain_interpolate(f)
2396 interpolate gain on frequency f based on gain_entry
2398 This option is also available as command. Default is @code{gain_interpolate(f)}.
2401 Set gain entry for gain_interpolate function. The expression can
2405 store gain entry at frequency f with value g
2407 This option is also available as command.
2410 Set filter delay in seconds. Higher value means more accurate.
2411 Default is @code{0.01}.
2414 Set filter accuracy in Hz. Lower value means more accurate.
2415 Default is @code{5}.
2418 Set window function. Acceptable values are:
2421 rectangular window, useful when gain curve is already smooth
2423 hann window (default)
2429 3-terms continuous 1st derivative nuttall window
2431 minimum 3-terms discontinuous nuttall window
2433 4-terms continuous 1st derivative nuttall window
2435 minimum 4-terms discontinuous nuttall (blackman-nuttall) window
2437 blackman-harris window
2441 If enabled, use fixed number of audio samples. This improves speed when
2442 filtering with large delay. Default is disabled.
2445 Enable multichannels evaluation on gain. Default is disabled.
2448 @subsection Examples
2453 firequalizer=gain='if(lt(f,1000), 0, -INF)'
2456 lowpass at 1000 Hz with gain_entry:
2458 firequalizer=gain_entry='entry(1000,0); entry(1001, -INF)'
2461 custom equalization:
2463 firequalizer=gain_entry='entry(100,0); entry(400, -4); entry(1000, -6); entry(2000, 0)'
2468 firequalizer=delay=0.1:fixed=on
2471 lowpass on left channel, highpass on right channel:
2473 firequalizer=gain='if(eq(chid,1), gain_interpolate(f), if(eq(chid,2), gain_interpolate(1e6+f), 0))'
2474 :gain_entry='entry(1000, 0); entry(1001,-INF); entry(1e6+1000,0)':multi=on
2479 Apply a flanging effect to the audio.
2481 The filter accepts the following options:
2485 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
2488 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
2491 Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
2495 Set percentage of delayed signal mixed with original. Range from 0 to 100.
2496 Default value is 71.
2499 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
2502 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
2503 Default value is @var{sinusoidal}.
2506 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
2507 Default value is 25.
2510 Set delay-line interpolation, @var{linear} or @var{quadratic}.
2511 Default is @var{linear}.
2516 Apply a high-pass filter with 3dB point frequency.
2517 The filter can be either single-pole, or double-pole (the default).
2518 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2520 The filter accepts the following options:
2524 Set frequency in Hz. Default is 3000.
2527 Set number of poles. Default is 2.
2530 Set method to specify band-width of filter.
2543 Specify the band-width of a filter in width_type units.
2544 Applies only to double-pole filter.
2545 The default is 0.707q and gives a Butterworth response.
2550 Join multiple input streams into one multi-channel stream.
2552 It accepts the following parameters:
2556 The number of input streams. It defaults to 2.
2558 @item channel_layout
2559 The desired output channel layout. It defaults to stereo.
2562 Map channels from inputs to output. The argument is a '|'-separated list of
2563 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
2564 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
2565 can be either the name of the input channel (e.g. FL for front left) or its
2566 index in the specified input stream. @var{out_channel} is the name of the output
2570 The filter will attempt to guess the mappings when they are not specified
2571 explicitly. It does so by first trying to find an unused matching input channel
2572 and if that fails it picks the first unused input channel.
2574 Join 3 inputs (with properly set channel layouts):
2576 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
2579 Build a 5.1 output from 6 single-channel streams:
2581 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
2582 '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'
2588 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
2590 To enable compilation of this filter you need to configure FFmpeg with
2591 @code{--enable-ladspa}.
2595 Specifies the name of LADSPA plugin library to load. If the environment
2596 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
2597 each one of the directories specified by the colon separated list in
2598 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
2599 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
2600 @file{/usr/lib/ladspa/}.
2603 Specifies the plugin within the library. Some libraries contain only
2604 one plugin, but others contain many of them. If this is not set filter
2605 will list all available plugins within the specified library.
2608 Set the '|' separated list of controls which are zero or more floating point
2609 values that determine the behavior of the loaded plugin (for example delay,
2611 Controls need to be defined using the following syntax:
2612 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
2613 @var{valuei} is the value set on the @var{i}-th control.
2614 Alternatively they can be also defined using the following syntax:
2615 @var{value0}|@var{value1}|@var{value2}|..., where
2616 @var{valuei} is the value set on the @var{i}-th control.
2617 If @option{controls} is set to @code{help}, all available controls and
2618 their valid ranges are printed.
2620 @item sample_rate, s
2621 Specify the sample rate, default to 44100. Only used if plugin have
2625 Set the number of samples per channel per each output frame, default
2626 is 1024. Only used if plugin have zero inputs.
2629 Set the minimum duration of the sourced audio. See
2630 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2631 for the accepted syntax.
2632 Note that the resulting duration may be greater than the specified duration,
2633 as the generated audio is always cut at the end of a complete frame.
2634 If not specified, or the expressed duration is negative, the audio is
2635 supposed to be generated forever.
2636 Only used if plugin have zero inputs.
2640 @subsection Examples
2644 List all available plugins within amp (LADSPA example plugin) library:
2650 List all available controls and their valid ranges for @code{vcf_notch}
2651 plugin from @code{VCF} library:
2653 ladspa=f=vcf:p=vcf_notch:c=help
2657 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
2660 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
2664 Add reverberation to the audio using TAP-plugins
2665 (Tom's Audio Processing plugins):
2667 ladspa=file=tap_reverb:tap_reverb
2671 Generate white noise, with 0.2 amplitude:
2673 ladspa=file=cmt:noise_source_white:c=c0=.2
2677 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
2678 @code{C* Audio Plugin Suite} (CAPS) library:
2680 ladspa=file=caps:Click:c=c1=20'
2684 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
2686 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
2690 Increase volume by 20dB using fast lookahead limiter from Steve Harris
2691 @code{SWH Plugins} collection:
2693 ladspa=fast_lookahead_limiter_1913:fastLookaheadLimiter:20|0|2
2697 Attenuate low frequencies using Multiband EQ from Steve Harris
2698 @code{SWH Plugins} collection:
2700 ladspa=mbeq_1197:mbeq:-24|-24|-24|0|0|0|0|0|0|0|0|0|0|0|0
2704 @subsection Commands
2706 This filter supports the following commands:
2709 Modify the @var{N}-th control value.
2711 If the specified value is not valid, it is ignored and prior one is kept.
2716 Apply a low-pass filter with 3dB point frequency.
2717 The filter can be either single-pole or double-pole (the default).
2718 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2720 The filter accepts the following options:
2724 Set frequency in Hz. Default is 500.
2727 Set number of poles. Default is 2.
2730 Set method to specify band-width of filter.
2743 Specify the band-width of a filter in width_type units.
2744 Applies only to double-pole filter.
2745 The default is 0.707q and gives a Butterworth response.
2751 Mix channels with specific gain levels. The filter accepts the output
2752 channel layout followed by a set of channels definitions.
2754 This filter is also designed to efficiently remap the channels of an audio
2757 The filter accepts parameters of the form:
2758 "@var{l}|@var{outdef}|@var{outdef}|..."
2762 output channel layout or number of channels
2765 output channel specification, of the form:
2766 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
2769 output channel to define, either a channel name (FL, FR, etc.) or a channel
2770 number (c0, c1, etc.)
2773 multiplicative coefficient for the channel, 1 leaving the volume unchanged
2776 input channel to use, see out_name for details; it is not possible to mix
2777 named and numbered input channels
2780 If the `=' in a channel specification is replaced by `<', then the gains for
2781 that specification will be renormalized so that the total is 1, thus
2782 avoiding clipping noise.
2784 @subsection Mixing examples
2786 For example, if you want to down-mix from stereo to mono, but with a bigger
2787 factor for the left channel:
2789 pan=1c|c0=0.9*c0+0.1*c1
2792 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
2793 7-channels surround:
2795 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
2798 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
2799 that should be preferred (see "-ac" option) unless you have very specific
2802 @subsection Remapping examples
2804 The channel remapping will be effective if, and only if:
2807 @item gain coefficients are zeroes or ones,
2808 @item only one input per channel output,
2811 If all these conditions are satisfied, the filter will notify the user ("Pure
2812 channel mapping detected"), and use an optimized and lossless method to do the
2815 For example, if you have a 5.1 source and want a stereo audio stream by
2816 dropping the extra channels:
2818 pan="stereo| c0=FL | c1=FR"
2821 Given the same source, you can also switch front left and front right channels
2822 and keep the input channel layout:
2824 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
2827 If the input is a stereo audio stream, you can mute the front left channel (and
2828 still keep the stereo channel layout) with:
2833 Still with a stereo audio stream input, you can copy the right channel in both
2834 front left and right:
2836 pan="stereo| c0=FR | c1=FR"
2841 ReplayGain scanner filter. This filter takes an audio stream as an input and
2842 outputs it unchanged.
2843 At end of filtering it displays @code{track_gain} and @code{track_peak}.
2847 Convert the audio sample format, sample rate and channel layout. It is
2848 not meant to be used directly.
2851 Apply time-stretching and pitch-shifting with librubberband.
2853 The filter accepts the following options:
2857 Set tempo scale factor.
2860 Set pitch scale factor.
2863 Set transients detector.
2864 Possible values are:
2873 Possible values are:
2882 Possible values are:
2889 Set processing window size.
2890 Possible values are:
2899 Possible values are:
2906 Enable formant preservation when shift pitching.
2907 Possible values are:
2915 Possible values are:
2924 Possible values are:
2931 @section sidechaincompress
2933 This filter acts like normal compressor but has the ability to compress
2934 detected signal using second input signal.
2935 It needs two input streams and returns one output stream.
2936 First input stream will be processed depending on second stream signal.
2937 The filtered signal then can be filtered with other filters in later stages of
2938 processing. See @ref{pan} and @ref{amerge} filter.
2940 The filter accepts the following options:
2944 Set input gain. Default is 1. Range is between 0.015625 and 64.
2947 If a signal of second stream raises above this level it will affect the gain
2948 reduction of first stream.
2949 By default is 0.125. Range is between 0.00097563 and 1.
2952 Set a ratio about which the signal is reduced. 1:2 means that if the level
2953 raised 4dB above the threshold, it will be only 2dB above after the reduction.
2954 Default is 2. Range is between 1 and 20.
2957 Amount of milliseconds the signal has to rise above the threshold before gain
2958 reduction starts. Default is 20. Range is between 0.01 and 2000.
2961 Amount of milliseconds the signal has to fall below the threshold before
2962 reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
2965 Set the amount by how much signal will be amplified after processing.
2966 Default is 2. Range is from 1 and 64.
2969 Curve the sharp knee around the threshold to enter gain reduction more softly.
2970 Default is 2.82843. Range is between 1 and 8.
2973 Choose if the @code{average} level between all channels of side-chain stream
2974 or the louder(@code{maximum}) channel of side-chain stream affects the
2975 reduction. Default is @code{average}.
2978 Should the exact signal be taken in case of @code{peak} or an RMS one in case
2979 of @code{rms}. Default is @code{rms} which is mainly smoother.
2982 Set sidechain gain. Default is 1. Range is between 0.015625 and 64.
2985 How much to use compressed signal in output. Default is 1.
2986 Range is between 0 and 1.
2989 @subsection Examples
2993 Full ffmpeg example taking 2 audio inputs, 1st input to be compressed
2994 depending on the signal of 2nd input and later compressed signal to be
2995 merged with 2nd input:
2997 ffmpeg -i main.flac -i sidechain.flac -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress[compr];[compr][mix]amerge"
3001 @section sidechaingate
3003 A sidechain gate acts like a normal (wideband) gate but has the ability to
3004 filter the detected signal before sending it to the gain reduction stage.
3005 Normally a gate uses the full range signal to detect a level above the
3007 For example: If you cut all lower frequencies from your sidechain signal
3008 the gate will decrease the volume of your track only if not enough highs
3009 appear. With this technique you are able to reduce the resonation of a
3010 natural drum or remove "rumbling" of muted strokes from a heavily distorted
3012 It needs two input streams and returns one output stream.
3013 First input stream will be processed depending on second stream signal.
3015 The filter accepts the following options:
3019 Set input level before filtering.
3020 Default is 1. Allowed range is from 0.015625 to 64.
3023 Set the level of gain reduction when the signal is below the threshold.
3024 Default is 0.06125. Allowed range is from 0 to 1.
3027 If a signal rises above this level the gain reduction is released.
3028 Default is 0.125. Allowed range is from 0 to 1.
3031 Set a ratio about which the signal is reduced.
3032 Default is 2. Allowed range is from 1 to 9000.
3035 Amount of milliseconds the signal has to rise above the threshold before gain
3037 Default is 20 milliseconds. Allowed range is from 0.01 to 9000.
3040 Amount of milliseconds the signal has to fall below the threshold before the
3041 reduction is increased again. Default is 250 milliseconds.
3042 Allowed range is from 0.01 to 9000.
3045 Set amount of amplification of signal after processing.
3046 Default is 1. Allowed range is from 1 to 64.
3049 Curve the sharp knee around the threshold to enter gain reduction more softly.
3050 Default is 2.828427125. Allowed range is from 1 to 8.
3053 Choose if exact signal should be taken for detection or an RMS like one.
3054 Default is rms. Can be peak or rms.
3057 Choose if the average level between all channels or the louder channel affects
3059 Default is average. Can be average or maximum.
3062 Set sidechain gain. Default is 1. Range is from 0.015625 to 64.
3065 @section silencedetect
3067 Detect silence in an audio stream.
3069 This filter logs a message when it detects that the input audio volume is less
3070 or equal to a noise tolerance value for a duration greater or equal to the
3071 minimum detected noise duration.
3073 The printed times and duration are expressed in seconds.
3075 The filter accepts the following options:
3079 Set silence duration until notification (default is 2 seconds).
3082 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
3083 specified value) or amplitude ratio. Default is -60dB, or 0.001.
3086 @subsection Examples
3090 Detect 5 seconds of silence with -50dB noise tolerance:
3092 silencedetect=n=-50dB:d=5
3096 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
3097 tolerance in @file{silence.mp3}:
3099 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
3103 @section silenceremove
3105 Remove silence from the beginning, middle or end of the audio.
3107 The filter accepts the following options:
3111 This value is used to indicate if audio should be trimmed at beginning of
3112 the audio. A value of zero indicates no silence should be trimmed from the
3113 beginning. When specifying a non-zero value, it trims audio up until it
3114 finds non-silence. Normally, when trimming silence from beginning of audio
3115 the @var{start_periods} will be @code{1} but it can be increased to higher
3116 values to trim all audio up to specific count of non-silence periods.
3117 Default value is @code{0}.
3119 @item start_duration
3120 Specify the amount of time that non-silence must be detected before it stops
3121 trimming audio. By increasing the duration, bursts of noises can be treated
3122 as silence and trimmed off. Default value is @code{0}.
3124 @item start_threshold
3125 This indicates what sample value should be treated as silence. For digital
3126 audio, a value of @code{0} may be fine but for audio recorded from analog,
3127 you may wish to increase the value to account for background noise.
3128 Can be specified in dB (in case "dB" is appended to the specified value)
3129 or amplitude ratio. Default value is @code{0}.
3132 Set the count for trimming silence from the end of audio.
3133 To remove silence from the middle of a file, specify a @var{stop_periods}
3134 that is negative. This value is then treated as a positive value and is
3135 used to indicate the effect should restart processing as specified by
3136 @var{start_periods}, making it suitable for removing periods of silence
3137 in the middle of the audio.
3138 Default value is @code{0}.
3141 Specify a duration of silence that must exist before audio is not copied any
3142 more. By specifying a higher duration, silence that is wanted can be left in
3144 Default value is @code{0}.
3146 @item stop_threshold
3147 This is the same as @option{start_threshold} but for trimming silence from
3149 Can be specified in dB (in case "dB" is appended to the specified value)
3150 or amplitude ratio. Default value is @code{0}.
3153 This indicate that @var{stop_duration} length of audio should be left intact
3154 at the beginning of each period of silence.
3155 For example, if you want to remove long pauses between words but do not want
3156 to remove the pauses completely. Default value is @code{0}.
3159 Set how is silence detected. Can be @code{rms} or @code{peak}. Second is faster
3160 and works better with digital silence which is exactly 0.
3161 Default value is @code{rms}.
3164 Set ratio used to calculate size of window for detecting silence.
3165 Default value is @code{0.02}. Allowed range is from @code{0} to @code{10}.
3168 @subsection Examples
3172 The following example shows how this filter can be used to start a recording
3173 that does not contain the delay at the start which usually occurs between
3174 pressing the record button and the start of the performance:
3176 silenceremove=1:5:0.02
3180 Trim all silence encountered from begining to end where there is more than 1
3181 second of silence in audio:
3183 silenceremove=0:0:0:-1:1:-90dB
3189 SOFAlizer uses head-related transfer functions (HRTFs) to create virtual
3190 loudspeakers around the user for binaural listening via headphones (audio
3191 formats up to 9 channels supported).
3192 The HRTFs are stored in SOFA files (see @url{http://www.sofacoustics.org/} for a database).
3193 SOFAlizer is developed at the Acoustics Research Institute (ARI) of the
3194 Austrian Academy of Sciences.
3196 To enable compilation of this filter you need to configure FFmpeg with
3197 @code{--enable-netcdf}.
3199 The filter accepts the following options:
3203 Set the SOFA file used for rendering.
3206 Set gain applied to audio. Value is in dB. Default is 0.
3209 Set rotation of virtual loudspeakers in deg. Default is 0.
3212 Set elevation of virtual speakers in deg. Default is 0.
3215 Set distance in meters between loudspeakers and the listener with near-field
3216 HRTFs. Default is 1.
3219 Set processing type. Can be @var{time} or @var{freq}. @var{time} is
3220 processing audio in time domain which is slow.
3221 @var{freq} is processing audio in frequency domain which is fast.
3222 Default is @var{freq}.
3225 Set custom positions of virtual loudspeakers. Syntax for this option is:
3226 <CH> <AZIM> <ELEV>[|<CH> <AZIM> <ELEV>|...].
3227 Each virtual loudspeaker is described with short channel name following with
3228 azimuth and elevation in degreees.
3229 Each virtual loudspeaker description is separated by '|'.
3230 For example to override front left and front right channel positions use:
3231 'speakers=FL 45 15|FR 345 15'.
3232 Descriptions with unrecognised channel names are ignored.
3235 @subsection Examples
3239 Using ClubFritz6 sofa file:
3241 sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=1
3245 Using ClubFritz12 sofa file and bigger radius with small rotation:
3247 sofalizer=sofa=/path/to/ClubFritz12.sofa:type=freq:radius=2:rotation=5
3251 Similar as above but with custom speaker positions for front left, front right, rear left and rear right
3252 and also with custom gain:
3254 "sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=2:speakers=FL 45|FR 315|RL 135|RR 225:gain=28"
3258 @section stereotools
3260 This filter has some handy utilities to manage stereo signals, for converting
3261 M/S stereo recordings to L/R signal while having control over the parameters
3262 or spreading the stereo image of master track.
3264 The filter accepts the following options:
3268 Set input level before filtering for both channels. Defaults is 1.
3269 Allowed range is from 0.015625 to 64.
3272 Set output level after filtering for both channels. Defaults is 1.
3273 Allowed range is from 0.015625 to 64.
3276 Set input balance between both channels. Default is 0.
3277 Allowed range is from -1 to 1.
3280 Set output balance between both channels. Default is 0.
3281 Allowed range is from -1 to 1.
3284 Enable softclipping. Results in analog distortion instead of harsh digital 0dB
3285 clipping. Disabled by default.
3288 Mute the left channel. Disabled by default.
3291 Mute the right channel. Disabled by default.
3294 Change the phase of the left channel. Disabled by default.
3297 Change the phase of the right channel. Disabled by default.
3300 Set stereo mode. Available values are:
3304 Left/Right to Left/Right, this is default.
3307 Left/Right to Mid/Side.
3310 Mid/Side to Left/Right.
3313 Left/Right to Left/Left.
3316 Left/Right to Right/Right.
3319 Left/Right to Left + Right.
3322 Left/Right to Right/Left.
3326 Set level of side signal. Default is 1.
3327 Allowed range is from 0.015625 to 64.
3330 Set balance of side signal. Default is 0.
3331 Allowed range is from -1 to 1.
3334 Set level of the middle signal. Default is 1.
3335 Allowed range is from 0.015625 to 64.
3338 Set middle signal pan. Default is 0. Allowed range is from -1 to 1.
3341 Set stereo base between mono and inversed channels. Default is 0.
3342 Allowed range is from -1 to 1.
3345 Set delay in milliseconds how much to delay left from right channel and
3346 vice versa. Default is 0. Allowed range is from -20 to 20.
3349 Set S/C level. Default is 1. Allowed range is from 1 to 100.
3352 Set the stereo phase in degrees. Default is 0. Allowed range is from 0 to 360.
3355 @subsection Examples
3359 Apply karaoke like effect:
3361 stereotools=mlev=0.015625
3365 Convert M/S signal to L/R:
3367 "stereotools=mode=ms>lr"
3371 @section stereowiden
3373 This filter enhance the stereo effect by suppressing signal common to both
3374 channels and by delaying the signal of left into right and vice versa,
3375 thereby widening the stereo effect.
3377 The filter accepts the following options:
3381 Time in milliseconds of the delay of left signal into right and vice versa.
3382 Default is 20 milliseconds.
3385 Amount of gain in delayed signal into right and vice versa. Gives a delay
3386 effect of left signal in right output and vice versa which gives widening
3387 effect. Default is 0.3.
3390 Cross feed of left into right with inverted phase. This helps in suppressing
3391 the mono. If the value is 1 it will cancel all the signal common to both
3392 channels. Default is 0.3.
3395 Set level of input signal of original channel. Default is 0.8.
3400 Use the NVIDIA Performance Primitives (libnpp) to perform scaling and/or pixel
3401 format conversion on CUDA video frames. Setting the output width and height
3402 works in the same way as for the @var{scale} filter.
3404 The following additional options are accepted:
3407 The pixel format of the output CUDA frames. If set to the string "same" (the
3408 default), the input format will be kept. Note that automatic format negotiation
3409 and conversion is not yet supported for hardware frames
3412 The interpolation algorithm used for resizing. One of the following:
3419 @item cubic2p_bspline
3420 2-parameter cubic (B=1, C=0)
3422 @item cubic2p_catmullrom
3423 2-parameter cubic (B=0, C=1/2)
3425 @item cubic2p_b05c03
3426 2-parameter cubic (B=1/2, C=3/10)
3437 Select frames to pass in output.
3441 Boost or cut treble (upper) frequencies of the audio using a two-pole
3442 shelving filter with a response similar to that of a standard
3443 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
3445 The filter accepts the following options:
3449 Give the gain at whichever is the lower of ~22 kHz and the
3450 Nyquist frequency. Its useful range is about -20 (for a large cut)
3451 to +20 (for a large boost). Beware of clipping when using a positive gain.
3454 Set the filter's central frequency and so can be used
3455 to extend or reduce the frequency range to be boosted or cut.
3456 The default value is @code{3000} Hz.
3459 Set method to specify band-width of filter.
3472 Determine how steep is the filter's shelf transition.
3477 Sinusoidal amplitude modulation.
3479 The filter accepts the following options:
3483 Modulation frequency in Hertz. Modulation frequencies in the subharmonic range
3484 (20 Hz or lower) will result in a tremolo effect.
3485 This filter may also be used as a ring modulator by specifying
3486 a modulation frequency higher than 20 Hz.
3487 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
3490 Depth of modulation as a percentage. Range is 0.0 - 1.0.
3491 Default value is 0.5.
3496 Sinusoidal phase modulation.
3498 The filter accepts the following options:
3502 Modulation frequency in Hertz.
3503 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
3506 Depth of modulation as a percentage. Range is 0.0 - 1.0.
3507 Default value is 0.5.
3512 Adjust the input audio volume.
3514 It accepts the following parameters:
3518 Set audio volume expression.
3520 Output values are clipped to the maximum value.
3522 The output audio volume is given by the relation:
3524 @var{output_volume} = @var{volume} * @var{input_volume}
3527 The default value for @var{volume} is "1.0".
3530 This parameter represents the mathematical precision.
3532 It determines which input sample formats will be allowed, which affects the
3533 precision of the volume scaling.
3537 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
3539 32-bit floating-point; this limits input sample format to FLT. (default)
3541 64-bit floating-point; this limits input sample format to DBL.
3545 Choose the behaviour on encountering ReplayGain side data in input frames.
3549 Remove ReplayGain side data, ignoring its contents (the default).
3552 Ignore ReplayGain side data, but leave it in the frame.
3555 Prefer the track gain, if present.
3558 Prefer the album gain, if present.
3561 @item replaygain_preamp
3562 Pre-amplification gain in dB to apply to the selected replaygain gain.
3564 Default value for @var{replaygain_preamp} is 0.0.
3567 Set when the volume expression is evaluated.
3569 It accepts the following values:
3572 only evaluate expression once during the filter initialization, or
3573 when the @samp{volume} command is sent
3576 evaluate expression for each incoming frame
3579 Default value is @samp{once}.
3582 The volume expression can contain the following parameters.
3586 frame number (starting at zero)
3589 @item nb_consumed_samples
3590 number of samples consumed by the filter
3592 number of samples in the current frame
3594 original frame position in the file
3600 PTS at start of stream
3602 time at start of stream
3608 last set volume value
3611 Note that when @option{eval} is set to @samp{once} only the
3612 @var{sample_rate} and @var{tb} variables are available, all other
3613 variables will evaluate to NAN.
3615 @subsection Commands
3617 This filter supports the following commands:
3620 Modify the volume expression.
3621 The command accepts the same syntax of the corresponding option.
3623 If the specified expression is not valid, it is kept at its current
3625 @item replaygain_noclip
3626 Prevent clipping by limiting the gain applied.
3628 Default value for @var{replaygain_noclip} is 1.
3632 @subsection Examples
3636 Halve the input audio volume:
3640 volume=volume=-6.0206dB
3643 In all the above example the named key for @option{volume} can be
3644 omitted, for example like in:
3650 Increase input audio power by 6 decibels using fixed-point precision:
3652 volume=volume=6dB:precision=fixed
3656 Fade volume after time 10 with an annihilation period of 5 seconds:
3658 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
3662 @section volumedetect
3664 Detect the volume of the input video.
3666 The filter has no parameters. The input is not modified. Statistics about
3667 the volume will be printed in the log when the input stream end is reached.
3669 In particular it will show the mean volume (root mean square), maximum
3670 volume (on a per-sample basis), and the beginning of a histogram of the
3671 registered volume values (from the maximum value to a cumulated 1/1000 of
3674 All volumes are in decibels relative to the maximum PCM value.
3676 @subsection Examples
3678 Here is an excerpt of the output:
3680 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
3681 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
3682 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
3683 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
3684 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
3685 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
3686 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
3687 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
3688 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
3694 The mean square energy is approximately -27 dB, or 10^-2.7.
3696 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
3698 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
3701 In other words, raising the volume by +4 dB does not cause any clipping,
3702 raising it by +5 dB causes clipping for 6 samples, etc.
3704 @c man end AUDIO FILTERS
3706 @chapter Audio Sources
3707 @c man begin AUDIO SOURCES
3709 Below is a description of the currently available audio sources.
3713 Buffer audio frames, and make them available to the filter chain.
3715 This source is mainly intended for a programmatic use, in particular
3716 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
3718 It accepts the following parameters:
3722 The timebase which will be used for timestamps of submitted frames. It must be
3723 either a floating-point number or in @var{numerator}/@var{denominator} form.
3726 The sample rate of the incoming audio buffers.
3729 The sample format of the incoming audio buffers.
3730 Either a sample format name or its corresponding integer representation from
3731 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
3733 @item channel_layout
3734 The channel layout of the incoming audio buffers.
3735 Either a channel layout name from channel_layout_map in
3736 @file{libavutil/channel_layout.c} or its corresponding integer representation
3737 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
3740 The number of channels of the incoming audio buffers.
3741 If both @var{channels} and @var{channel_layout} are specified, then they
3746 @subsection Examples
3749 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
3752 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
3753 Since the sample format with name "s16p" corresponds to the number
3754 6 and the "stereo" channel layout corresponds to the value 0x3, this is
3757 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
3762 Generate an audio signal specified by an expression.
3764 This source accepts in input one or more expressions (one for each
3765 channel), which are evaluated and used to generate a corresponding
3768 This source accepts the following options:
3772 Set the '|'-separated expressions list for each separate channel. In case the
3773 @option{channel_layout} option is not specified, the selected channel layout
3774 depends on the number of provided expressions. Otherwise the last
3775 specified expression is applied to the remaining output channels.
3777 @item channel_layout, c
3778 Set the channel layout. The number of channels in the specified layout
3779 must be equal to the number of specified expressions.
3782 Set the minimum duration of the sourced audio. See
3783 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
3784 for the accepted syntax.
3785 Note that the resulting duration may be greater than the specified
3786 duration, as the generated audio is always cut at the end of a
3789 If not specified, or the expressed duration is negative, the audio is
3790 supposed to be generated forever.
3793 Set the number of samples per channel per each output frame,
3796 @item sample_rate, s
3797 Specify the sample rate, default to 44100.
3800 Each expression in @var{exprs} can contain the following constants:
3804 number of the evaluated sample, starting from 0
3807 time of the evaluated sample expressed in seconds, starting from 0
3814 @subsection Examples
3824 Generate a sin signal with frequency of 440 Hz, set sample rate to
3827 aevalsrc="sin(440*2*PI*t):s=8000"
3831 Generate a two channels signal, specify the channel layout (Front
3832 Center + Back Center) explicitly:
3834 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
3838 Generate white noise:
3840 aevalsrc="-2+random(0)"
3844 Generate an amplitude modulated signal:
3846 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
3850 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
3852 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
3859 The null audio source, return unprocessed audio frames. It is mainly useful
3860 as a template and to be employed in analysis / debugging tools, or as
3861 the source for filters which ignore the input data (for example the sox
3864 This source accepts the following options:
3868 @item channel_layout, cl
3870 Specifies the channel layout, and can be either an integer or a string
3871 representing a channel layout. The default value of @var{channel_layout}
3874 Check the channel_layout_map definition in
3875 @file{libavutil/channel_layout.c} for the mapping between strings and
3876 channel layout values.
3878 @item sample_rate, r
3879 Specifies the sample rate, and defaults to 44100.
3882 Set the number of samples per requested frames.
3886 @subsection Examples
3890 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
3892 anullsrc=r=48000:cl=4
3896 Do the same operation with a more obvious syntax:
3898 anullsrc=r=48000:cl=mono
3902 All the parameters need to be explicitly defined.
3906 Synthesize a voice utterance using the libflite library.
3908 To enable compilation of this filter you need to configure FFmpeg with
3909 @code{--enable-libflite}.
3911 Note that the flite library is not thread-safe.
3913 The filter accepts the following options:
3918 If set to 1, list the names of the available voices and exit
3919 immediately. Default value is 0.
3922 Set the maximum number of samples per frame. Default value is 512.
3925 Set the filename containing the text to speak.
3928 Set the text to speak.
3931 Set the voice to use for the speech synthesis. Default value is
3932 @code{kal}. See also the @var{list_voices} option.
3935 @subsection Examples
3939 Read from file @file{speech.txt}, and synthesize the text using the
3940 standard flite voice:
3942 flite=textfile=speech.txt
3946 Read the specified text selecting the @code{slt} voice:
3948 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
3952 Input text to ffmpeg:
3954 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
3958 Make @file{ffplay} speak the specified text, using @code{flite} and
3959 the @code{lavfi} device:
3961 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
3965 For more information about libflite, check:
3966 @url{http://www.speech.cs.cmu.edu/flite/}
3970 Generate a noise audio signal.
3972 The filter accepts the following options:
3975 @item sample_rate, r
3976 Specify the sample rate. Default value is 48000 Hz.
3979 Specify the amplitude (0.0 - 1.0) of the generated audio stream. Default value
3983 Specify the duration of the generated audio stream. Not specifying this option
3984 results in noise with an infinite length.
3986 @item color, colour, c
3987 Specify the color of noise. Available noise colors are white, pink, and brown.
3988 Default color is white.
3991 Specify a value used to seed the PRNG.
3994 Set the number of samples per each output frame, default is 1024.
3997 @subsection Examples
4002 Generate 60 seconds of pink noise, with a 44.1 kHz sampling rate and an amplitude of 0.5:
4004 anoisesrc=d=60:c=pink:r=44100:a=0.5
4010 Generate an audio signal made of a sine wave with amplitude 1/8.
4012 The audio signal is bit-exact.
4014 The filter accepts the following options:
4019 Set the carrier frequency. Default is 440 Hz.
4021 @item beep_factor, b
4022 Enable a periodic beep every second with frequency @var{beep_factor} times
4023 the carrier frequency. Default is 0, meaning the beep is disabled.
4025 @item sample_rate, r
4026 Specify the sample rate, default is 44100.
4029 Specify the duration of the generated audio stream.
4031 @item samples_per_frame
4032 Set the number of samples per output frame.
4034 The expression can contain the following constants:
4038 The (sequential) number of the output audio frame, starting from 0.
4041 The PTS (Presentation TimeStamp) of the output audio frame,
4042 expressed in @var{TB} units.
4045 The PTS of the output audio frame, expressed in seconds.
4048 The timebase of the output audio frames.
4051 Default is @code{1024}.
4054 @subsection Examples
4059 Generate a simple 440 Hz sine wave:
4065 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
4069 sine=frequency=220:beep_factor=4:duration=5
4073 Generate a 1 kHz sine wave following @code{1602,1601,1602,1601,1602} NTSC
4076 sine=1000:samples_per_frame='st(0,mod(n,5)); 1602-not(not(eq(ld(0),1)+eq(ld(0),3)))'
4080 @c man end AUDIO SOURCES
4082 @chapter Audio Sinks
4083 @c man begin AUDIO SINKS
4085 Below is a description of the currently available audio sinks.
4087 @section abuffersink
4089 Buffer audio frames, and make them available to the end of filter chain.
4091 This sink is mainly intended for programmatic use, in particular
4092 through the interface defined in @file{libavfilter/buffersink.h}
4093 or the options system.
4095 It accepts a pointer to an AVABufferSinkContext structure, which
4096 defines the incoming buffers' formats, to be passed as the opaque
4097 parameter to @code{avfilter_init_filter} for initialization.
4100 Null audio sink; do absolutely nothing with the input audio. It is
4101 mainly useful as a template and for use in analysis / debugging
4104 @c man end AUDIO SINKS
4106 @chapter Video Filters
4107 @c man begin VIDEO FILTERS
4109 When you configure your FFmpeg build, you can disable any of the
4110 existing filters using @code{--disable-filters}.
4111 The configure output will show the video filters included in your
4114 Below is a description of the currently available video filters.
4116 @section alphaextract
4118 Extract the alpha component from the input as a grayscale video. This
4119 is especially useful with the @var{alphamerge} filter.
4123 Add or replace the alpha component of the primary input with the
4124 grayscale value of a second input. This is intended for use with
4125 @var{alphaextract} to allow the transmission or storage of frame
4126 sequences that have alpha in a format that doesn't support an alpha
4129 For example, to reconstruct full frames from a normal YUV-encoded video
4130 and a separate video created with @var{alphaextract}, you might use:
4132 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
4135 Since this filter is designed for reconstruction, it operates on frame
4136 sequences without considering timestamps, and terminates when either
4137 input reaches end of stream. This will cause problems if your encoding
4138 pipeline drops frames. If you're trying to apply an image as an
4139 overlay to a video stream, consider the @var{overlay} filter instead.
4143 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
4144 and libavformat to work. On the other hand, it is limited to ASS (Advanced
4145 Substation Alpha) subtitles files.
4147 This filter accepts the following option in addition to the common options from
4148 the @ref{subtitles} filter:
4152 Set the shaping engine
4154 Available values are:
4157 The default libass shaping engine, which is the best available.
4159 Fast, font-agnostic shaper that can do only substitutions
4161 Slower shaper using OpenType for substitutions and positioning
4164 The default is @code{auto}.
4168 Apply an Adaptive Temporal Averaging Denoiser to the video input.
4170 The filter accepts the following options:
4174 Set threshold A for 1st plane. Default is 0.02.
4175 Valid range is 0 to 0.3.
4178 Set threshold B for 1st plane. Default is 0.04.
4179 Valid range is 0 to 5.
4182 Set threshold A for 2nd plane. Default is 0.02.
4183 Valid range is 0 to 0.3.
4186 Set threshold B for 2nd plane. Default is 0.04.
4187 Valid range is 0 to 5.
4190 Set threshold A for 3rd plane. Default is 0.02.
4191 Valid range is 0 to 0.3.
4194 Set threshold B for 3rd plane. Default is 0.04.
4195 Valid range is 0 to 5.
4197 Threshold A is designed to react on abrupt changes in the input signal and
4198 threshold B is designed to react on continuous changes in the input signal.
4201 Set number of frames filter will use for averaging. Default is 33. Must be odd
4202 number in range [5, 129].
4207 Compute the bounding box for the non-black pixels in the input frame
4210 This filter computes the bounding box containing all the pixels with a
4211 luminance value greater than the minimum allowed value.
4212 The parameters describing the bounding box are printed on the filter
4215 The filter accepts the following option:
4219 Set the minimal luminance value. Default is @code{16}.
4222 @section blackdetect
4224 Detect video intervals that are (almost) completely black. Can be
4225 useful to detect chapter transitions, commercials, or invalid
4226 recordings. Output lines contains the time for the start, end and
4227 duration of the detected black interval expressed in seconds.
4229 In order to display the output lines, you need to set the loglevel at
4230 least to the AV_LOG_INFO value.
4232 The filter accepts the following options:
4235 @item black_min_duration, d
4236 Set the minimum detected black duration expressed in seconds. It must
4237 be a non-negative floating point number.
4239 Default value is 2.0.
4241 @item picture_black_ratio_th, pic_th
4242 Set the threshold for considering a picture "black".
4243 Express the minimum value for the ratio:
4245 @var{nb_black_pixels} / @var{nb_pixels}
4248 for which a picture is considered black.
4249 Default value is 0.98.
4251 @item pixel_black_th, pix_th
4252 Set the threshold for considering a pixel "black".
4254 The threshold expresses the maximum pixel luminance value for which a
4255 pixel is considered "black". The provided value is scaled according to
4256 the following equation:
4258 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
4261 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
4262 the input video format, the range is [0-255] for YUV full-range
4263 formats and [16-235] for YUV non full-range formats.
4265 Default value is 0.10.
4268 The following example sets the maximum pixel threshold to the minimum
4269 value, and detects only black intervals of 2 or more seconds:
4271 blackdetect=d=2:pix_th=0.00
4276 Detect frames that are (almost) completely black. Can be useful to
4277 detect chapter transitions or commercials. Output lines consist of
4278 the frame number of the detected frame, the percentage of blackness,
4279 the position in the file if known or -1 and the timestamp in seconds.
4281 In order to display the output lines, you need to set the loglevel at
4282 least to the AV_LOG_INFO value.
4284 It accepts the following parameters:
4289 The percentage of the pixels that have to be below the threshold; it defaults to
4292 @item threshold, thresh
4293 The threshold below which a pixel value is considered black; it defaults to
4298 @section blend, tblend
4300 Blend two video frames into each other.
4302 The @code{blend} filter takes two input streams and outputs one
4303 stream, the first input is the "top" layer and second input is
4304 "bottom" layer. Output terminates when shortest input terminates.
4306 The @code{tblend} (time blend) filter takes two consecutive frames
4307 from one single stream, and outputs the result obtained by blending
4308 the new frame on top of the old frame.
4310 A description of the accepted options follows.
4318 Set blend mode for specific pixel component or all pixel components in case
4319 of @var{all_mode}. Default value is @code{normal}.
4321 Available values for component modes are:
4362 Set blend opacity for specific pixel component or all pixel components in case
4363 of @var{all_opacity}. Only used in combination with pixel component blend modes.
4370 Set blend expression for specific pixel component or all pixel components in case
4371 of @var{all_expr}. Note that related mode options will be ignored if those are set.
4373 The expressions can use the following variables:
4377 The sequential number of the filtered frame, starting from @code{0}.
4381 the coordinates of the current sample
4385 the width and height of currently filtered plane
4389 Width and height scale depending on the currently filtered plane. It is the
4390 ratio between the corresponding luma plane number of pixels and the current
4391 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4392 @code{0.5,0.5} for chroma planes.
4395 Time of the current frame, expressed in seconds.
4398 Value of pixel component at current location for first video frame (top layer).
4401 Value of pixel component at current location for second video frame (bottom layer).
4405 Force termination when the shortest input terminates. Default is
4406 @code{0}. This option is only defined for the @code{blend} filter.
4409 Continue applying the last bottom frame after the end of the stream. A value of
4410 @code{0} disable the filter after the last frame of the bottom layer is reached.
4411 Default is @code{1}. This option is only defined for the @code{blend} filter.
4414 @subsection Examples
4418 Apply transition from bottom layer to top layer in first 10 seconds:
4420 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
4424 Apply 1x1 checkerboard effect:
4426 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
4430 Apply uncover left effect:
4432 blend=all_expr='if(gte(N*SW+X,W),A,B)'
4436 Apply uncover down effect:
4438 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
4442 Apply uncover up-left effect:
4444 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
4448 Split diagonally video and shows top and bottom layer on each side:
4450 blend=all_expr=if(gt(X,Y*(W/H)),A,B)
4454 Display differences between the current and the previous frame:
4456 tblend=all_mode=difference128
4462 Deinterlace the input video ("bwdif" stands for "Bob Weaver
4463 Deinterlacing Filter").
4465 Motion adaptive deinterlacing based on yadif with the use of w3fdif and cubic
4466 interpolation algorithms.
4467 It accepts the following parameters:
4471 The interlacing mode to adopt. It accepts one of the following values:
4475 Output one frame for each frame.
4477 Output one frame for each field.
4480 The default value is @code{send_field}.
4483 The picture field parity assumed for the input interlaced video. It accepts one
4484 of the following values:
4488 Assume the top field is first.
4490 Assume the bottom field is first.
4492 Enable automatic detection of field parity.
4495 The default value is @code{auto}.
4496 If the interlacing is unknown or the decoder does not export this information,
4497 top field first will be assumed.
4500 Specify which frames to deinterlace. Accept one of the following
4505 Deinterlace all frames.
4507 Only deinterlace frames marked as interlaced.
4510 The default value is @code{all}.
4515 Apply a boxblur algorithm to the input video.
4517 It accepts the following parameters:
4521 @item luma_radius, lr
4522 @item luma_power, lp
4523 @item chroma_radius, cr
4524 @item chroma_power, cp
4525 @item alpha_radius, ar
4526 @item alpha_power, ap
4530 A description of the accepted options follows.
4533 @item luma_radius, lr
4534 @item chroma_radius, cr
4535 @item alpha_radius, ar
4536 Set an expression for the box radius in pixels used for blurring the
4537 corresponding input plane.
4539 The radius value must be a non-negative number, and must not be
4540 greater than the value of the expression @code{min(w,h)/2} for the
4541 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
4544 Default value for @option{luma_radius} is "2". If not specified,
4545 @option{chroma_radius} and @option{alpha_radius} default to the
4546 corresponding value set for @option{luma_radius}.
4548 The expressions can contain the following constants:
4552 The input width and height in pixels.
4556 The input chroma image width and height in pixels.
4560 The horizontal and vertical chroma subsample values. For example, for the
4561 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
4564 @item luma_power, lp
4565 @item chroma_power, cp
4566 @item alpha_power, ap
4567 Specify how many times the boxblur filter is applied to the
4568 corresponding plane.
4570 Default value for @option{luma_power} is 2. If not specified,
4571 @option{chroma_power} and @option{alpha_power} default to the
4572 corresponding value set for @option{luma_power}.
4574 A value of 0 will disable the effect.
4577 @subsection Examples
4581 Apply a boxblur filter with the luma, chroma, and alpha radii
4584 boxblur=luma_radius=2:luma_power=1
4589 Set the luma radius to 2, and alpha and chroma radius to 0:
4591 boxblur=2:1:cr=0:ar=0
4595 Set the luma and chroma radii to a fraction of the video dimension:
4597 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
4602 YUV colorspace color/chroma keying.
4604 The filter accepts the following options:
4608 The color which will be replaced with transparency.
4611 Similarity percentage with the key color.
4613 0.01 matches only the exact key color, while 1.0 matches everything.
4618 0.0 makes pixels either fully transparent, or not transparent at all.
4620 Higher values result in semi-transparent pixels, with a higher transparency
4621 the more similar the pixels color is to the key color.
4624 Signals that the color passed is already in YUV instead of RGB.
4626 Litteral colors like "green" or "red" don't make sense with this enabled anymore.
4627 This can be used to pass exact YUV values as hexadecimal numbers.
4630 @subsection Examples
4634 Make every green pixel in the input image transparent:
4636 ffmpeg -i input.png -vf chromakey=green out.png
4640 Overlay a greenscreen-video on top of a static black background.
4642 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
4648 Display CIE color diagram with pixels overlaid onto it.
4650 The filter acccepts the following options:
4665 @item uhdtv, rec2020
4678 Set what gamuts to draw.
4680 See @code{system} option for avaiable values.
4683 Set ciescope size, by default set to 512.
4686 Set intensity used to map input pixel values to CIE diagram.
4689 Set contrast used to draw tongue colors that are out of active color system gamut.
4692 Correct gamma displayed on scope, by default enabled.
4695 Show white point on CIE diagram, by default disabled.
4698 Set input gamma. Used only with XYZ input color space.
4703 Visualize information exported by some codecs.
4705 Some codecs can export information through frames using side-data or other
4706 means. For example, some MPEG based codecs export motion vectors through the
4707 @var{export_mvs} flag in the codec @option{flags2} option.
4709 The filter accepts the following option:
4713 Set motion vectors to visualize.
4715 Available flags for @var{mv} are:
4719 forward predicted MVs of P-frames
4721 forward predicted MVs of B-frames
4723 backward predicted MVs of B-frames
4727 Display quantization parameters using the chroma planes
4730 @subsection Examples
4734 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
4736 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
4740 @section colorbalance
4741 Modify intensity of primary colors (red, green and blue) of input frames.
4743 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
4744 regions for the red-cyan, green-magenta or blue-yellow balance.
4746 A positive adjustment value shifts the balance towards the primary color, a negative
4747 value towards the complementary color.
4749 The filter accepts the following options:
4755 Adjust red, green and blue shadows (darkest pixels).
4760 Adjust red, green and blue midtones (medium pixels).
4765 Adjust red, green and blue highlights (brightest pixels).
4767 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
4770 @subsection Examples
4774 Add red color cast to shadows:
4781 RGB colorspace color keying.
4783 The filter accepts the following options:
4787 The color which will be replaced with transparency.
4790 Similarity percentage with the key color.
4792 0.01 matches only the exact key color, while 1.0 matches everything.
4797 0.0 makes pixels either fully transparent, or not transparent at all.
4799 Higher values result in semi-transparent pixels, with a higher transparency
4800 the more similar the pixels color is to the key color.
4803 @subsection Examples
4807 Make every green pixel in the input image transparent:
4809 ffmpeg -i input.png -vf colorkey=green out.png
4813 Overlay a greenscreen-video on top of a static background image.
4815 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
4819 @section colorlevels
4821 Adjust video input frames using levels.
4823 The filter accepts the following options:
4830 Adjust red, green, blue and alpha input black point.
4831 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
4837 Adjust red, green, blue and alpha input white point.
4838 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
4840 Input levels are used to lighten highlights (bright tones), darken shadows
4841 (dark tones), change the balance of bright and dark tones.
4847 Adjust red, green, blue and alpha output black point.
4848 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
4854 Adjust red, green, blue and alpha output white point.
4855 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
4857 Output levels allows manual selection of a constrained output level range.
4860 @subsection Examples
4864 Make video output darker:
4866 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
4872 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
4876 Make video output lighter:
4878 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
4882 Increase brightness:
4884 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
4888 @section colorchannelmixer
4890 Adjust video input frames by re-mixing color channels.
4892 This filter modifies a color channel by adding the values associated to
4893 the other channels of the same pixels. For example if the value to
4894 modify is red, the output value will be:
4896 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
4899 The filter accepts the following options:
4906 Adjust contribution of input red, green, blue and alpha channels for output red channel.
4907 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
4913 Adjust contribution of input red, green, blue and alpha channels for output green channel.
4914 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
4920 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
4921 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
4927 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
4928 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
4930 Allowed ranges for options are @code{[-2.0, 2.0]}.
4933 @subsection Examples
4937 Convert source to grayscale:
4939 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
4942 Simulate sepia tones:
4944 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
4948 @section colormatrix
4950 Convert color matrix.
4952 The filter accepts the following options:
4957 Specify the source and destination color matrix. Both values must be
4960 The accepted values are:
4976 For example to convert from BT.601 to SMPTE-240M, use the command:
4978 colormatrix=bt601:smpte240m
4983 Convert colorspace, transfer characteristics or color primaries.
4985 The filter accepts the following options:
4989 Specify all color properties at once.
4991 The accepted values are:
5020 Specify output colorspace.
5022 The accepted values are:
5031 BT.470BG or BT.601-6 625
5034 SMPTE-170M or BT.601-6 525
5040 BT.2020 with non-constant luminance
5045 Specify output transfer characteristics.
5047 The accepted values are:
5053 Constant gamma of 2.2
5056 Constant gamma of 2.8
5059 SMPTE-170M, BT.601-6 625 or BT.601-6 525
5065 BT.2020 for 10-bits content
5068 BT.2020 for 12-bits content
5073 Specify output color primaries.
5075 The accepted values are:
5084 BT.470BG or BT.601-6 625
5087 SMPTE-170M or BT.601-6 525
5098 Specify output color range.
5100 The accepted values are:
5103 MPEG (restricted) range
5111 Specify output color format.
5113 The accepted values are:
5116 YUV 4:2:0 planar 8-bits
5119 YUV 4:2:0 planar 10-bits
5122 YUV 4:2:0 planar 12-bits
5125 YUV 4:2:2 planar 8-bits
5128 YUV 4:2:2 planar 10-bits
5131 YUV 4:2:2 planar 12-bits
5134 YUV 4:4:4 planar 8-bits
5137 YUV 4:4:4 planar 10-bits
5140 YUV 4:4:4 planar 12-bits
5145 Do a fast conversion, which skips gamma/primary correction. This will take
5146 significantly less CPU, but will be mathematically incorrect. To get output
5147 compatible with that produced by the colormatrix filter, use fast=1.
5150 Specify dithering mode.
5152 The accepted values are:
5158 Floyd-Steinberg dithering
5162 Whitepoint adaptation mode.
5164 The accepted values are:
5167 Bradford whitepoint adaptation
5170 von Kries whitepoint adaptation
5173 identity whitepoint adaptation (i.e. no whitepoint adaptation)
5178 The filter converts the transfer characteristics, color space and color
5179 primaries to the specified user values. The output value, if not specified,
5180 is set to a default value based on the "all" property. If that property is
5181 also not specified, the filter will log an error. The output color range and
5182 format default to the same value as the input color range and format. The
5183 input transfer characteristics, color space, color primaries and color range
5184 should be set on the input data. If any of these are missing, the filter will
5185 log an error and no conversion will take place.
5187 For example to convert the input to SMPTE-240M, use the command:
5189 colorspace=smpte240m
5192 @section convolution
5194 Apply convolution 3x3 or 5x5 filter.
5196 The filter accepts the following options:
5203 Set matrix for each plane.
5204 Matrix is sequence of 9 or 25 signed integers.
5210 Set multiplier for calculated value for each plane.
5216 Set bias for each plane. This value is added to the result of the multiplication.
5217 Useful for making the overall image brighter or darker. Default is 0.0.
5220 @subsection Examples
5226 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"
5232 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"
5238 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"
5244 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"
5250 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"
5256 Copy the input source unchanged to the output. This is mainly useful for
5261 Video filtering on GPU using Apple's CoreImage API on OSX.
5263 Hardware acceleration is based on an OpenGL context. Usually, this means it is
5264 processed by video hardware. However, software-based OpenGL implementations
5265 exist which means there is no guarantee for hardware processing. It depends on
5268 There are many filters and image generators provided by Apple that come with a
5269 large variety of options. The filter has to be referenced by its name along
5272 The coreimage filter accepts the following options:
5275 List all available filters and generators along with all their respective
5276 options as well as possible minimum and maximum values along with the default
5283 Specify all filters by their respective name and options.
5284 Use @var{list_filters} to determine all valid filter names and options.
5285 Numerical options are specified by a float value and are automatically clamped
5286 to their respective value range. Vector and color options have to be specified
5287 by a list of space separated float values. Character escaping has to be done.
5288 A special option name @code{default} is available to use default options for a
5291 It is required to specify either @code{default} or at least one of the filter options.
5292 All omitted options are used with their default values.
5293 The syntax of the filter string is as follows:
5295 filter=<NAME>@@<OPTION>=<VALUE>[@@<OPTION>=<VALUE>][@@...][#<NAME>@@<OPTION>=<VALUE>[@@<OPTION>=<VALUE>][@@...]][#...]
5299 Specify a rectangle where the output of the filter chain is copied into the
5300 input image. It is given by a list of space separated float values:
5302 output_rect=x\ y\ width\ height
5304 If not given, the output rectangle equals the dimensions of the input image.
5305 The output rectangle is automatically cropped at the borders of the input
5306 image. Negative values are valid for each component.
5308 output_rect=25\ 25\ 100\ 100
5312 Several filters can be chained for successive processing without GPU-HOST
5313 transfers allowing for fast processing of complex filter chains.
5314 Currently, only filters with zero (generators) or exactly one (filters) input
5315 image and one output image are supported. Also, transition filters are not yet
5318 Some filters generate output images with additional padding depending on the
5319 respective filter kernel. The padding is automatically removed to ensure the
5320 filter output has the same size as the input image.
5322 For image generators, the size of the output image is determined by the
5323 previous output image of the filter chain or the input image of the whole
5324 filterchain, respectively. The generators do not use the pixel information of
5325 this image to generate their output. However, the generated output is
5326 blended onto this image, resulting in partial or complete coverage of the
5329 The @ref{coreimagesrc} video source can be used for generating input images
5330 which are directly fed into the filter chain. By using it, providing input
5331 images by another video source or an input video is not required.
5333 @subsection Examples
5338 List all filters available:
5340 coreimage=list_filters=true
5344 Use the CIBoxBlur filter with default options to blur an image:
5346 coreimage=filter=CIBoxBlur@@default
5350 Use a filter chain with CISepiaTone at default values and CIVignetteEffect with
5351 its center at 100x100 and a radius of 50 pixels:
5353 coreimage=filter=CIBoxBlur@@default#CIVignetteEffect@@inputCenter=100\ 100@@inputRadius=50
5357 Use nullsrc and CIQRCodeGenerator to create a QR code for the FFmpeg homepage,
5358 given as complete and escaped command-line for Apple's standard bash shell:
5360 ffmpeg -f lavfi -i nullsrc=s=100x100,coreimage=filter=CIQRCodeGenerator@@inputMessage=https\\\\\://FFmpeg.org/@@inputCorrectionLevel=H -frames:v 1 QRCode.png
5366 Crop the input video to given dimensions.
5368 It accepts the following parameters:
5372 The width of the output video. It defaults to @code{iw}.
5373 This expression is evaluated only once during the filter
5374 configuration, or when the @samp{w} or @samp{out_w} command is sent.
5377 The height of the output video. It defaults to @code{ih}.
5378 This expression is evaluated only once during the filter
5379 configuration, or when the @samp{h} or @samp{out_h} command is sent.
5382 The horizontal position, in the input video, of the left edge of the output
5383 video. It defaults to @code{(in_w-out_w)/2}.
5384 This expression is evaluated per-frame.
5387 The vertical position, in the input video, of the top edge of the output video.
5388 It defaults to @code{(in_h-out_h)/2}.
5389 This expression is evaluated per-frame.
5392 If set to 1 will force the output display aspect ratio
5393 to be the same of the input, by changing the output sample aspect
5394 ratio. It defaults to 0.
5397 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
5398 expressions containing the following constants:
5403 The computed values for @var{x} and @var{y}. They are evaluated for
5408 The input width and height.
5412 These are the same as @var{in_w} and @var{in_h}.
5416 The output (cropped) width and height.
5420 These are the same as @var{out_w} and @var{out_h}.
5423 same as @var{iw} / @var{ih}
5426 input sample aspect ratio
5429 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
5433 horizontal and vertical chroma subsample values. For example for the
5434 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5437 The number of the input frame, starting from 0.
5440 the position in the file of the input frame, NAN if unknown
5443 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
5447 The expression for @var{out_w} may depend on the value of @var{out_h},
5448 and the expression for @var{out_h} may depend on @var{out_w}, but they
5449 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
5450 evaluated after @var{out_w} and @var{out_h}.
5452 The @var{x} and @var{y} parameters specify the expressions for the
5453 position of the top-left corner of the output (non-cropped) area. They
5454 are evaluated for each frame. If the evaluated value is not valid, it
5455 is approximated to the nearest valid value.
5457 The expression for @var{x} may depend on @var{y}, and the expression
5458 for @var{y} may depend on @var{x}.
5460 @subsection Examples
5464 Crop area with size 100x100 at position (12,34).
5469 Using named options, the example above becomes:
5471 crop=w=100:h=100:x=12:y=34
5475 Crop the central input area with size 100x100:
5481 Crop the central input area with size 2/3 of the input video:
5483 crop=2/3*in_w:2/3*in_h
5487 Crop the input video central square:
5494 Delimit the rectangle with the top-left corner placed at position
5495 100:100 and the right-bottom corner corresponding to the right-bottom
5496 corner of the input image.
5498 crop=in_w-100:in_h-100:100:100
5502 Crop 10 pixels from the left and right borders, and 20 pixels from
5503 the top and bottom borders
5505 crop=in_w-2*10:in_h-2*20
5509 Keep only the bottom right quarter of the input image:
5511 crop=in_w/2:in_h/2:in_w/2:in_h/2
5515 Crop height for getting Greek harmony:
5517 crop=in_w:1/PHI*in_w
5521 Apply trembling effect:
5523 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)
5527 Apply erratic camera effect depending on timestamp:
5529 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)"
5533 Set x depending on the value of y:
5535 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
5539 @subsection Commands
5541 This filter supports the following commands:
5547 Set width/height of the output video and the horizontal/vertical position
5549 The command accepts the same syntax of the corresponding option.
5551 If the specified expression is not valid, it is kept at its current
5557 Auto-detect the crop size.
5559 It calculates the necessary cropping parameters and prints the
5560 recommended parameters via the logging system. The detected dimensions
5561 correspond to the non-black area of the input video.
5563 It accepts the following parameters:
5568 Set higher black value threshold, which can be optionally specified
5569 from nothing (0) to everything (255 for 8bit based formats). An intensity
5570 value greater to the set value is considered non-black. It defaults to 24.
5571 You can also specify a value between 0.0 and 1.0 which will be scaled depending
5572 on the bitdepth of the pixel format.
5575 The value which the width/height should be divisible by. It defaults to
5576 16. The offset is automatically adjusted to center the video. Use 2 to
5577 get only even dimensions (needed for 4:2:2 video). 16 is best when
5578 encoding to most video codecs.
5580 @item reset_count, reset
5581 Set the counter that determines after how many frames cropdetect will
5582 reset the previously detected largest video area and start over to
5583 detect the current optimal crop area. Default value is 0.
5585 This can be useful when channel logos distort the video area. 0
5586 indicates 'never reset', and returns the largest area encountered during
5593 Apply color adjustments using curves.
5595 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
5596 component (red, green and blue) has its values defined by @var{N} key points
5597 tied from each other using a smooth curve. The x-axis represents the pixel
5598 values from the input frame, and the y-axis the new pixel values to be set for
5601 By default, a component curve is defined by the two points @var{(0;0)} and
5602 @var{(1;1)}. This creates a straight line where each original pixel value is
5603 "adjusted" to its own value, which means no change to the image.
5605 The filter allows you to redefine these two points and add some more. A new
5606 curve (using a natural cubic spline interpolation) will be define to pass
5607 smoothly through all these new coordinates. The new defined points needs to be
5608 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
5609 be in the @var{[0;1]} interval. If the computed curves happened to go outside
5610 the vector spaces, the values will be clipped accordingly.
5612 If there is no key point defined in @code{x=0}, the filter will automatically
5613 insert a @var{(0;0)} point. In the same way, if there is no key point defined
5614 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
5616 The filter accepts the following options:
5620 Select one of the available color presets. This option can be used in addition
5621 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
5622 options takes priority on the preset values.
5623 Available presets are:
5626 @item color_negative
5629 @item increase_contrast
5631 @item linear_contrast
5632 @item medium_contrast
5634 @item strong_contrast
5637 Default is @code{none}.
5639 Set the master key points. These points will define a second pass mapping. It
5640 is sometimes called a "luminance" or "value" mapping. It can be used with
5641 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
5642 post-processing LUT.
5644 Set the key points for the red component.
5646 Set the key points for the green component.
5648 Set the key points for the blue component.
5650 Set the key points for all components (not including master).
5651 Can be used in addition to the other key points component
5652 options. In this case, the unset component(s) will fallback on this
5653 @option{all} setting.
5655 Specify a Photoshop curves file (@code{.acv}) to import the settings from.
5658 To avoid some filtergraph syntax conflicts, each key points list need to be
5659 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
5661 @subsection Examples
5665 Increase slightly the middle level of blue:
5667 curves=blue='0.5/0.58'
5673 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
5675 Here we obtain the following coordinates for each components:
5678 @code{(0;0.11) (0.42;0.51) (1;0.95)}
5680 @code{(0;0) (0.50;0.48) (1;1)}
5682 @code{(0;0.22) (0.49;0.44) (1;0.80)}
5686 The previous example can also be achieved with the associated built-in preset:
5688 curves=preset=vintage
5698 Use a Photoshop preset and redefine the points of the green component:
5700 curves=psfile='MyCurvesPresets/purple.acv':green='0.45/0.53'
5706 Video data analysis filter.
5708 This filter shows hexadecimal pixel values of part of video.
5710 The filter accepts the following options:
5714 Set output video size.
5717 Set x offset from where to pick pixels.
5720 Set y offset from where to pick pixels.
5723 Set scope mode, can be one of the following:
5726 Draw hexadecimal pixel values with white color on black background.
5729 Draw hexadecimal pixel values with input video pixel color on black
5733 Draw hexadecimal pixel values on color background picked from input video,
5734 the text color is picked in such way so its always visible.
5738 Draw rows and columns numbers on left and top of video.
5743 Denoise frames using 2D DCT (frequency domain filtering).
5745 This filter is not designed for real time.
5747 The filter accepts the following options:
5751 Set the noise sigma constant.
5753 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
5754 coefficient (absolute value) below this threshold with be dropped.
5756 If you need a more advanced filtering, see @option{expr}.
5758 Default is @code{0}.
5761 Set number overlapping pixels for each block. Since the filter can be slow, you
5762 may want to reduce this value, at the cost of a less effective filter and the
5763 risk of various artefacts.
5765 If the overlapping value doesn't permit processing the whole input width or
5766 height, a warning will be displayed and according borders won't be denoised.
5768 Default value is @var{blocksize}-1, which is the best possible setting.
5771 Set the coefficient factor expression.
5773 For each coefficient of a DCT block, this expression will be evaluated as a
5774 multiplier value for the coefficient.
5776 If this is option is set, the @option{sigma} option will be ignored.
5778 The absolute value of the coefficient can be accessed through the @var{c}
5782 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
5783 @var{blocksize}, which is the width and height of the processed blocks.
5785 The default value is @var{3} (8x8) and can be raised to @var{4} for a
5786 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
5787 on the speed processing. Also, a larger block size does not necessarily means a
5791 @subsection Examples
5793 Apply a denoise with a @option{sigma} of @code{4.5}:
5798 The same operation can be achieved using the expression system:
5800 dctdnoiz=e='gte(c, 4.5*3)'
5803 Violent denoise using a block size of @code{16x16}:
5810 Remove banding artifacts from input video.
5811 It works by replacing banded pixels with average value of referenced pixels.
5813 The filter accepts the following options:
5820 Set banding detection threshold for each plane. Default is 0.02.
5821 Valid range is 0.00003 to 0.5.
5822 If difference between current pixel and reference pixel is less than threshold,
5823 it will be considered as banded.
5826 Banding detection range in pixels. Default is 16. If positive, random number
5827 in range 0 to set value will be used. If negative, exact absolute value
5829 The range defines square of four pixels around current pixel.
5832 Set direction in radians from which four pixel will be compared. If positive,
5833 random direction from 0 to set direction will be picked. If negative, exact of
5834 absolute value will be picked. For example direction 0, -PI or -2*PI radians
5835 will pick only pixels on same row and -PI/2 will pick only pixels on same
5839 If enabled, current pixel is compared with average value of all four
5840 surrounding pixels. The default is enabled. If disabled current pixel is
5841 compared with all four surrounding pixels. The pixel is considered banded
5842 if only all four differences with surrounding pixels are less than threshold.
5848 Drop duplicated frames at regular intervals.
5850 The filter accepts the following options:
5854 Set the number of frames from which one will be dropped. Setting this to
5855 @var{N} means one frame in every batch of @var{N} frames will be dropped.
5856 Default is @code{5}.
5859 Set the threshold for duplicate detection. If the difference metric for a frame
5860 is less than or equal to this value, then it is declared as duplicate. Default
5864 Set scene change threshold. Default is @code{15}.
5868 Set the size of the x and y-axis blocks used during metric calculations.
5869 Larger blocks give better noise suppression, but also give worse detection of
5870 small movements. Must be a power of two. Default is @code{32}.
5873 Mark main input as a pre-processed input and activate clean source input
5874 stream. This allows the input to be pre-processed with various filters to help
5875 the metrics calculation while keeping the frame selection lossless. When set to
5876 @code{1}, the first stream is for the pre-processed input, and the second
5877 stream is the clean source from where the kept frames are chosen. Default is
5881 Set whether or not chroma is considered in the metric calculations. Default is
5887 Apply deflate effect to the video.
5889 This filter replaces the pixel by the local(3x3) average by taking into account
5890 only values lower than the pixel.
5892 It accepts the following options:
5899 Limit the maximum change for each plane, default is 65535.
5900 If 0, plane will remain unchanged.
5905 Remove judder produced by partially interlaced telecined content.
5907 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
5908 source was partially telecined content then the output of @code{pullup,dejudder}
5909 will have a variable frame rate. May change the recorded frame rate of the
5910 container. Aside from that change, this filter will not affect constant frame
5913 The option available in this filter is:
5917 Specify the length of the window over which the judder repeats.
5919 Accepts any integer greater than 1. Useful values are:
5923 If the original was telecined from 24 to 30 fps (Film to NTSC).
5926 If the original was telecined from 25 to 30 fps (PAL to NTSC).
5929 If a mixture of the two.
5932 The default is @samp{4}.
5937 Suppress a TV station logo by a simple interpolation of the surrounding
5938 pixels. Just set a rectangle covering the logo and watch it disappear
5939 (and sometimes something even uglier appear - your mileage may vary).
5941 It accepts the following parameters:
5946 Specify the top left corner coordinates of the logo. They must be
5951 Specify the width and height of the logo to clear. They must be
5955 Specify the thickness of the fuzzy edge of the rectangle (added to
5956 @var{w} and @var{h}). The default value is 1. This option is
5957 deprecated, setting higher values should no longer be necessary and
5961 When set to 1, a green rectangle is drawn on the screen to simplify
5962 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
5963 The default value is 0.
5965 The rectangle is drawn on the outermost pixels which will be (partly)
5966 replaced with interpolated values. The values of the next pixels
5967 immediately outside this rectangle in each direction will be used to
5968 compute the interpolated pixel values inside the rectangle.
5972 @subsection Examples
5976 Set a rectangle covering the area with top left corner coordinates 0,0
5977 and size 100x77, and a band of size 10:
5979 delogo=x=0:y=0:w=100:h=77:band=10
5986 Attempt to fix small changes in horizontal and/or vertical shift. This
5987 filter helps remove camera shake from hand-holding a camera, bumping a
5988 tripod, moving on a vehicle, etc.
5990 The filter accepts the following options:
5998 Specify a rectangular area where to limit the search for motion
6000 If desired the search for motion vectors can be limited to a
6001 rectangular area of the frame defined by its top left corner, width
6002 and height. These parameters have the same meaning as the drawbox
6003 filter which can be used to visualise the position of the bounding
6006 This is useful when simultaneous movement of subjects within the frame
6007 might be confused for camera motion by the motion vector search.
6009 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
6010 then the full frame is used. This allows later options to be set
6011 without specifying the bounding box for the motion vector search.
6013 Default - search the whole frame.
6017 Specify the maximum extent of movement in x and y directions in the
6018 range 0-64 pixels. Default 16.
6021 Specify how to generate pixels to fill blanks at the edge of the
6022 frame. Available values are:
6025 Fill zeroes at blank locations
6027 Original image at blank locations
6029 Extruded edge value at blank locations
6031 Mirrored edge at blank locations
6033 Default value is @samp{mirror}.
6036 Specify the blocksize to use for motion search. Range 4-128 pixels,
6040 Specify the contrast threshold for blocks. Only blocks with more than
6041 the specified contrast (difference between darkest and lightest
6042 pixels) will be considered. Range 1-255, default 125.
6045 Specify the search strategy. Available values are:
6048 Set exhaustive search
6050 Set less exhaustive search.
6052 Default value is @samp{exhaustive}.
6055 If set then a detailed log of the motion search is written to the
6059 If set to 1, specify using OpenCL capabilities, only available if
6060 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
6066 Apply an exact inverse of the telecine operation. It requires a predefined
6067 pattern specified using the pattern option which must be the same as that passed
6068 to the telecine filter.
6070 This filter accepts the following options:
6079 The default value is @code{top}.
6083 A string of numbers representing the pulldown pattern you wish to apply.
6084 The default value is @code{23}.
6087 A number representing position of the first frame with respect to the telecine
6088 pattern. This is to be used if the stream is cut. The default value is @code{0}.
6093 Apply dilation effect to the video.
6095 This filter replaces the pixel by the local(3x3) maximum.
6097 It accepts the following options:
6104 Limit the maximum change for each plane, default is 65535.
6105 If 0, plane will remain unchanged.
6108 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
6111 Flags to local 3x3 coordinates maps like this:
6120 Displace pixels as indicated by second and third input stream.
6122 It takes three input streams and outputs one stream, the first input is the
6123 source, and second and third input are displacement maps.
6125 The second input specifies how much to displace pixels along the
6126 x-axis, while the third input specifies how much to displace pixels
6128 If one of displacement map streams terminates, last frame from that
6129 displacement map will be used.
6131 Note that once generated, displacements maps can be reused over and over again.
6133 A description of the accepted options follows.
6137 Set displace behavior for pixels that are out of range.
6139 Available values are:
6142 Missing pixels are replaced by black pixels.
6145 Adjacent pixels will spread out to replace missing pixels.
6148 Out of range pixels are wrapped so they point to pixels of other side.
6150 Default is @samp{smear}.
6154 @subsection Examples
6158 Add ripple effect to rgb input of video size hd720:
6160 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
6164 Add wave effect to rgb input of video size hd720:
6166 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
6172 Draw a colored box on the input image.
6174 It accepts the following parameters:
6179 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
6183 The expressions which specify the width and height of the box; if 0 they are interpreted as
6184 the input width and height. It defaults to 0.
6187 Specify the color of the box to write. For the general syntax of this option,
6188 check the "Color" section in the ffmpeg-utils manual. If the special
6189 value @code{invert} is used, the box edge color is the same as the
6190 video with inverted luma.
6193 The expression which sets the thickness of the box edge. Default value is @code{3}.
6195 See below for the list of accepted constants.
6198 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
6199 following constants:
6203 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
6207 horizontal and vertical chroma subsample values. For example for the
6208 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6212 The input width and height.
6215 The input sample aspect ratio.
6219 The x and y offset coordinates where the box is drawn.
6223 The width and height of the drawn box.
6226 The thickness of the drawn box.
6228 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
6229 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
6233 @subsection Examples
6237 Draw a black box around the edge of the input image:
6243 Draw a box with color red and an opacity of 50%:
6245 drawbox=10:20:200:60:red@@0.5
6248 The previous example can be specified as:
6250 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
6254 Fill the box with pink color:
6256 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
6260 Draw a 2-pixel red 2.40:1 mask:
6262 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
6266 @section drawgraph, adrawgraph
6268 Draw a graph using input video or audio metadata.
6270 It accepts the following parameters:
6274 Set 1st frame metadata key from which metadata values will be used to draw a graph.
6277 Set 1st foreground color expression.
6280 Set 2nd frame metadata key from which metadata values will be used to draw a graph.
6283 Set 2nd foreground color expression.
6286 Set 3rd frame metadata key from which metadata values will be used to draw a graph.
6289 Set 3rd foreground color expression.
6292 Set 4th frame metadata key from which metadata values will be used to draw a graph.
6295 Set 4th foreground color expression.
6298 Set minimal value of metadata value.
6301 Set maximal value of metadata value.
6304 Set graph background color. Default is white.
6309 Available values for mode is:
6316 Default is @code{line}.
6321 Available values for slide is:
6324 Draw new frame when right border is reached.
6327 Replace old columns with new ones.
6330 Scroll from right to left.
6333 Scroll from left to right.
6336 Default is @code{frame}.
6339 Set size of graph video. For the syntax of this option, check the
6340 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
6341 The default value is @code{900x256}.
6343 The foreground color expressions can use the following variables:
6346 Minimal value of metadata value.
6349 Maximal value of metadata value.
6352 Current metadata key value.
6355 The color is defined as 0xAABBGGRR.
6358 Example using metadata from @ref{signalstats} filter:
6360 signalstats,drawgraph=lavfi.signalstats.YAVG:min=0:max=255
6363 Example using metadata from @ref{ebur128} filter:
6365 ebur128=metadata=1,adrawgraph=lavfi.r128.M:min=-120:max=5
6370 Draw a grid on the input image.
6372 It accepts the following parameters:
6377 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
6381 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
6382 input width and height, respectively, minus @code{thickness}, so image gets
6383 framed. Default to 0.
6386 Specify the color of the grid. For the general syntax of this option,
6387 check the "Color" section in the ffmpeg-utils manual. If the special
6388 value @code{invert} is used, the grid color is the same as the
6389 video with inverted luma.
6392 The expression which sets the thickness of the grid line. Default value is @code{1}.
6394 See below for the list of accepted constants.
6397 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
6398 following constants:
6402 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
6406 horizontal and vertical chroma subsample values. For example for the
6407 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6411 The input grid cell width and height.
6414 The input sample aspect ratio.
6418 The x and y coordinates of some point of grid intersection (meant to configure offset).
6422 The width and height of the drawn cell.
6425 The thickness of the drawn cell.
6427 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
6428 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
6432 @subsection Examples
6436 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
6438 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
6442 Draw a white 3x3 grid with an opacity of 50%:
6444 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
6451 Draw a text string or text from a specified file on top of a video, using the
6452 libfreetype library.
6454 To enable compilation of this filter, you need to configure FFmpeg with
6455 @code{--enable-libfreetype}.
6456 To enable default font fallback and the @var{font} option you need to
6457 configure FFmpeg with @code{--enable-libfontconfig}.
6458 To enable the @var{text_shaping} option, you need to configure FFmpeg with
6459 @code{--enable-libfribidi}.
6463 It accepts the following parameters:
6468 Used to draw a box around text using the background color.
6469 The value must be either 1 (enable) or 0 (disable).
6470 The default value of @var{box} is 0.
6473 Set the width of the border to be drawn around the box using @var{boxcolor}.
6474 The default value of @var{boxborderw} is 0.
6477 The color to be used for drawing box around text. For the syntax of this
6478 option, check the "Color" section in the ffmpeg-utils manual.
6480 The default value of @var{boxcolor} is "white".
6483 Set the width of the border to be drawn around the text using @var{bordercolor}.
6484 The default value of @var{borderw} is 0.
6487 Set the color to be used for drawing border around text. For the syntax of this
6488 option, check the "Color" section in the ffmpeg-utils manual.
6490 The default value of @var{bordercolor} is "black".
6493 Select how the @var{text} is expanded. Can be either @code{none},
6494 @code{strftime} (deprecated) or
6495 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
6499 If true, check and fix text coords to avoid clipping.
6502 The color to be used for drawing fonts. For the syntax of this option, check
6503 the "Color" section in the ffmpeg-utils manual.
6505 The default value of @var{fontcolor} is "black".
6507 @item fontcolor_expr
6508 String which is expanded the same way as @var{text} to obtain dynamic
6509 @var{fontcolor} value. By default this option has empty value and is not
6510 processed. When this option is set, it overrides @var{fontcolor} option.
6513 The font family to be used for drawing text. By default Sans.
6516 The font file to be used for drawing text. The path must be included.
6517 This parameter is mandatory if the fontconfig support is disabled.
6520 This option does not exist, please see the timeline system
6523 Draw the text applying alpha blending. The value can
6524 be either a number between 0.0 and 1.0
6525 The expression accepts the same variables @var{x, y} do.
6526 The default value is 1.
6527 Please see fontcolor_expr
6530 The font size to be used for drawing text.
6531 The default value of @var{fontsize} is 16.
6534 If set to 1, attempt to shape the text (for example, reverse the order of
6535 right-to-left text and join Arabic characters) before drawing it.
6536 Otherwise, just draw the text exactly as given.
6537 By default 1 (if supported).
6540 The flags to be used for loading the fonts.
6542 The flags map the corresponding flags supported by libfreetype, and are
6543 a combination of the following values:
6550 @item vertical_layout
6551 @item force_autohint
6554 @item ignore_global_advance_width
6556 @item ignore_transform
6562 Default value is "default".
6564 For more information consult the documentation for the FT_LOAD_*
6568 The color to be used for drawing a shadow behind the drawn text. For the
6569 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
6571 The default value of @var{shadowcolor} is "black".
6575 The x and y offsets for the text shadow position with respect to the
6576 position of the text. They can be either positive or negative
6577 values. The default value for both is "0".
6580 The starting frame number for the n/frame_num variable. The default value
6584 The size in number of spaces to use for rendering the tab.
6588 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
6589 format. It can be used with or without text parameter. @var{timecode_rate}
6590 option must be specified.
6592 @item timecode_rate, rate, r
6593 Set the timecode frame rate (timecode only).
6596 The text string to be drawn. The text must be a sequence of UTF-8
6598 This parameter is mandatory if no file is specified with the parameter
6602 A text file containing text to be drawn. The text must be a sequence
6603 of UTF-8 encoded characters.
6605 This parameter is mandatory if no text string is specified with the
6606 parameter @var{text}.
6608 If both @var{text} and @var{textfile} are specified, an error is thrown.
6611 If set to 1, the @var{textfile} will be reloaded before each frame.
6612 Be sure to update it atomically, or it may be read partially, or even fail.
6616 The expressions which specify the offsets where text will be drawn
6617 within the video frame. They are relative to the top/left border of the
6620 The default value of @var{x} and @var{y} is "0".
6622 See below for the list of accepted constants and functions.
6625 The parameters for @var{x} and @var{y} are expressions containing the
6626 following constants and functions:
6630 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
6634 horizontal and vertical chroma subsample values. For example for the
6635 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6638 the height of each text line
6646 @item max_glyph_a, ascent
6647 the maximum distance from the baseline to the highest/upper grid
6648 coordinate used to place a glyph outline point, for all the rendered
6650 It is a positive value, due to the grid's orientation with the Y axis
6653 @item max_glyph_d, descent
6654 the maximum distance from the baseline to the lowest grid coordinate
6655 used to place a glyph outline point, for all the rendered glyphs.
6656 This is a negative value, due to the grid's orientation, with the Y axis
6660 maximum glyph height, that is the maximum height for all the glyphs
6661 contained in the rendered text, it is equivalent to @var{ascent} -
6665 maximum glyph width, that is the maximum width for all the glyphs
6666 contained in the rendered text
6669 the number of input frame, starting from 0
6671 @item rand(min, max)
6672 return a random number included between @var{min} and @var{max}
6675 The input sample aspect ratio.
6678 timestamp expressed in seconds, NAN if the input timestamp is unknown
6681 the height of the rendered text
6684 the width of the rendered text
6688 the x and y offset coordinates where the text is drawn.
6690 These parameters allow the @var{x} and @var{y} expressions to refer
6691 each other, so you can for example specify @code{y=x/dar}.
6694 @anchor{drawtext_expansion}
6695 @subsection Text expansion
6697 If @option{expansion} is set to @code{strftime},
6698 the filter recognizes strftime() sequences in the provided text and
6699 expands them accordingly. Check the documentation of strftime(). This
6700 feature is deprecated.
6702 If @option{expansion} is set to @code{none}, the text is printed verbatim.
6704 If @option{expansion} is set to @code{normal} (which is the default),
6705 the following expansion mechanism is used.
6707 The backslash character @samp{\}, followed by any character, always expands to
6708 the second character.
6710 Sequence of the form @code{%@{...@}} are expanded. The text between the
6711 braces is a function name, possibly followed by arguments separated by ':'.
6712 If the arguments contain special characters or delimiters (':' or '@}'),
6713 they should be escaped.
6715 Note that they probably must also be escaped as the value for the
6716 @option{text} option in the filter argument string and as the filter
6717 argument in the filtergraph description, and possibly also for the shell,
6718 that makes up to four levels of escaping; using a text file avoids these
6721 The following functions are available:
6726 The expression evaluation result.
6728 It must take one argument specifying the expression to be evaluated,
6729 which accepts the same constants and functions as the @var{x} and
6730 @var{y} values. Note that not all constants should be used, for
6731 example the text size is not known when evaluating the expression, so
6732 the constants @var{text_w} and @var{text_h} will have an undefined
6735 @item expr_int_format, eif
6736 Evaluate the expression's value and output as formatted integer.
6738 The first argument is the expression to be evaluated, just as for the @var{expr} function.
6739 The second argument specifies the output format. Allowed values are @samp{x},
6740 @samp{X}, @samp{d} and @samp{u}. They are treated exactly as in the
6741 @code{printf} function.
6742 The third parameter is optional and sets the number of positions taken by the output.
6743 It can be used to add padding with zeros from the left.
6746 The time at which the filter is running, expressed in UTC.
6747 It can accept an argument: a strftime() format string.
6750 The time at which the filter is running, expressed in the local time zone.
6751 It can accept an argument: a strftime() format string.
6754 Frame metadata. Takes one or two arguments.
6756 The first argument is mandatory and specifies the metadata key.
6758 The second argument is optional and specifies a default value, used when the
6759 metadata key is not found or empty.
6762 The frame number, starting from 0.
6765 A 1 character description of the current picture type.
6768 The timestamp of the current frame.
6769 It can take up to three arguments.
6771 The first argument is the format of the timestamp; it defaults to @code{flt}
6772 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
6773 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
6774 @code{gmtime} stands for the timestamp of the frame formatted as UTC time;
6775 @code{localtime} stands for the timestamp of the frame formatted as
6776 local time zone time.
6778 The second argument is an offset added to the timestamp.
6780 If the format is set to @code{localtime} or @code{gmtime},
6781 a third argument may be supplied: a strftime() format string.
6782 By default, @var{YYYY-MM-DD HH:MM:SS} format will be used.
6785 @subsection Examples
6789 Draw "Test Text" with font FreeSerif, using the default values for the
6790 optional parameters.
6793 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
6797 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
6798 and y=50 (counting from the top-left corner of the screen), text is
6799 yellow with a red box around it. Both the text and the box have an
6803 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
6804 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
6807 Note that the double quotes are not necessary if spaces are not used
6808 within the parameter list.
6811 Show the text at the center of the video frame:
6813 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h)/2"
6817 Show the text at a random position, switching to a new position every 30 seconds:
6819 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=if(eq(mod(t\,30)\,0)\,rand(0\,(w-text_w))\,x):y=if(eq(mod(t\,30)\,0)\,rand(0\,(h-text_h))\,y)"
6823 Show a text line sliding from right to left in the last row of the video
6824 frame. The file @file{LONG_LINE} is assumed to contain a single line
6827 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
6831 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
6833 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
6837 Draw a single green letter "g", at the center of the input video.
6838 The glyph baseline is placed at half screen height.
6840 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
6844 Show text for 1 second every 3 seconds:
6846 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
6850 Use fontconfig to set the font. Note that the colons need to be escaped.
6852 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
6856 Print the date of a real-time encoding (see strftime(3)):
6858 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
6862 Show text fading in and out (appearing/disappearing):
6865 DS=1.0 # display start
6866 DE=10.0 # display end
6867 FID=1.5 # fade in duration
6868 FOD=5 # fade out duration
6869 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 @}"
6874 For more information about libfreetype, check:
6875 @url{http://www.freetype.org/}.
6877 For more information about fontconfig, check:
6878 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
6880 For more information about libfribidi, check:
6881 @url{http://fribidi.org/}.
6885 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
6887 The filter accepts the following options:
6892 Set low and high threshold values used by the Canny thresholding
6895 The high threshold selects the "strong" edge pixels, which are then
6896 connected through 8-connectivity with the "weak" edge pixels selected
6897 by the low threshold.
6899 @var{low} and @var{high} threshold values must be chosen in the range
6900 [0,1], and @var{low} should be lesser or equal to @var{high}.
6902 Default value for @var{low} is @code{20/255}, and default value for @var{high}
6906 Define the drawing mode.
6910 Draw white/gray wires on black background.
6913 Mix the colors to create a paint/cartoon effect.
6916 Default value is @var{wires}.
6919 @subsection Examples
6923 Standard edge detection with custom values for the hysteresis thresholding:
6925 edgedetect=low=0.1:high=0.4
6929 Painting effect without thresholding:
6931 edgedetect=mode=colormix:high=0
6936 Set brightness, contrast, saturation and approximate gamma adjustment.
6938 The filter accepts the following options:
6942 Set the contrast expression. The value must be a float value in range
6943 @code{-2.0} to @code{2.0}. The default value is "1".
6946 Set the brightness expression. The value must be a float value in
6947 range @code{-1.0} to @code{1.0}. The default value is "0".
6950 Set the saturation expression. The value must be a float in
6951 range @code{0.0} to @code{3.0}. The default value is "1".
6954 Set the gamma expression. The value must be a float in range
6955 @code{0.1} to @code{10.0}. The default value is "1".
6958 Set the gamma expression for red. The value must be a float in
6959 range @code{0.1} to @code{10.0}. The default value is "1".
6962 Set the gamma expression for green. The value must be a float in range
6963 @code{0.1} to @code{10.0}. The default value is "1".
6966 Set the gamma expression for blue. The value must be a float in range
6967 @code{0.1} to @code{10.0}. The default value is "1".
6970 Set the gamma weight expression. It can be used to reduce the effect
6971 of a high gamma value on bright image areas, e.g. keep them from
6972 getting overamplified and just plain white. The value must be a float
6973 in range @code{0.0} to @code{1.0}. A value of @code{0.0} turns the
6974 gamma correction all the way down while @code{1.0} leaves it at its
6975 full strength. Default is "1".
6978 Set when the expressions for brightness, contrast, saturation and
6979 gamma expressions are evaluated.
6981 It accepts the following values:
6984 only evaluate expressions once during the filter initialization or
6985 when a command is processed
6988 evaluate expressions for each incoming frame
6991 Default value is @samp{init}.
6994 The expressions accept the following parameters:
6997 frame count of the input frame starting from 0
7000 byte position of the corresponding packet in the input file, NAN if
7004 frame rate of the input video, NAN if the input frame rate is unknown
7007 timestamp expressed in seconds, NAN if the input timestamp is unknown
7010 @subsection Commands
7011 The filter supports the following commands:
7015 Set the contrast expression.
7018 Set the brightness expression.
7021 Set the saturation expression.
7024 Set the gamma expression.
7027 Set the gamma_r expression.
7030 Set gamma_g expression.
7033 Set gamma_b expression.
7036 Set gamma_weight expression.
7038 The command accepts the same syntax of the corresponding option.
7040 If the specified expression is not valid, it is kept at its current
7047 Apply erosion effect to the video.
7049 This filter replaces the pixel by the local(3x3) minimum.
7051 It accepts the following options:
7058 Limit the maximum change for each plane, default is 65535.
7059 If 0, plane will remain unchanged.
7062 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
7065 Flags to local 3x3 coordinates maps like this:
7072 @section extractplanes
7074 Extract color channel components from input video stream into
7075 separate grayscale video streams.
7077 The filter accepts the following option:
7081 Set plane(s) to extract.
7083 Available values for planes are:
7094 Choosing planes not available in the input will result in an error.
7095 That means you cannot select @code{r}, @code{g}, @code{b} planes
7096 with @code{y}, @code{u}, @code{v} planes at same time.
7099 @subsection Examples
7103 Extract luma, u and v color channel component from input video frame
7104 into 3 grayscale outputs:
7106 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
7112 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
7114 For each input image, the filter will compute the optimal mapping from
7115 the input to the output given the codebook length, that is the number
7116 of distinct output colors.
7118 This filter accepts the following options.
7121 @item codebook_length, l
7122 Set codebook length. The value must be a positive integer, and
7123 represents the number of distinct output colors. Default value is 256.
7126 Set the maximum number of iterations to apply for computing the optimal
7127 mapping. The higher the value the better the result and the higher the
7128 computation time. Default value is 1.
7131 Set a random seed, must be an integer included between 0 and
7132 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
7133 will try to use a good random seed on a best effort basis.
7136 Set pal8 output pixel format. This option does not work with codebook
7137 length greater than 256.
7142 Apply a fade-in/out effect to the input video.
7144 It accepts the following parameters:
7148 The effect type can be either "in" for a fade-in, or "out" for a fade-out
7150 Default is @code{in}.
7152 @item start_frame, s
7153 Specify the number of the frame to start applying the fade
7154 effect at. Default is 0.
7157 The number of frames that the fade effect lasts. At the end of the
7158 fade-in effect, the output video will have the same intensity as the input video.
7159 At the end of the fade-out transition, the output video will be filled with the
7160 selected @option{color}.
7164 If set to 1, fade only alpha channel, if one exists on the input.
7167 @item start_time, st
7168 Specify the timestamp (in seconds) of the frame to start to apply the fade
7169 effect. If both start_frame and start_time are specified, the fade will start at
7170 whichever comes last. Default is 0.
7173 The number of seconds for which the fade effect has to last. At the end of the
7174 fade-in effect the output video will have the same intensity as the input video,
7175 at the end of the fade-out transition the output video will be filled with the
7176 selected @option{color}.
7177 If both duration and nb_frames are specified, duration is used. Default is 0
7178 (nb_frames is used by default).
7181 Specify the color of the fade. Default is "black".
7184 @subsection Examples
7188 Fade in the first 30 frames of video:
7193 The command above is equivalent to:
7199 Fade out the last 45 frames of a 200-frame video:
7202 fade=type=out:start_frame=155:nb_frames=45
7206 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
7208 fade=in:0:25, fade=out:975:25
7212 Make the first 5 frames yellow, then fade in from frame 5-24:
7214 fade=in:5:20:color=yellow
7218 Fade in alpha over first 25 frames of video:
7220 fade=in:0:25:alpha=1
7224 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
7226 fade=t=in:st=5.5:d=0.5
7232 Apply arbitrary expressions to samples in frequency domain
7236 Adjust the dc value (gain) of the luma plane of the image. The filter
7237 accepts an integer value in range @code{0} to @code{1000}. The default
7238 value is set to @code{0}.
7241 Adjust the dc value (gain) of the 1st chroma plane of the image. The
7242 filter accepts an integer value in range @code{0} to @code{1000}. The
7243 default value is set to @code{0}.
7246 Adjust the dc value (gain) of the 2nd chroma plane of the image. The
7247 filter accepts an integer value in range @code{0} to @code{1000}. The
7248 default value is set to @code{0}.
7251 Set the frequency domain weight expression for the luma plane.
7254 Set the frequency domain weight expression for the 1st chroma plane.
7257 Set the frequency domain weight expression for the 2nd chroma plane.
7259 The filter accepts the following variables:
7262 The coordinates of the current sample.
7266 The width and height of the image.
7269 @subsection Examples
7275 fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
7281 fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
7287 fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
7293 fftfilt=dc_Y=0:weight_Y='exp(-4 * ((Y+X)/(W+H)))'
7300 Extract a single field from an interlaced image using stride
7301 arithmetic to avoid wasting CPU time. The output frames are marked as
7304 The filter accepts the following options:
7308 Specify whether to extract the top (if the value is @code{0} or
7309 @code{top}) or the bottom field (if the value is @code{1} or
7315 Create new frames by copying the top and bottom fields from surrounding frames
7316 supplied as numbers by the hint file.
7320 Set file containing hints: absolute/relative frame numbers.
7322 There must be one line for each frame in a clip. Each line must contain two
7323 numbers separated by the comma, optionally followed by @code{-} or @code{+}.
7324 Numbers supplied on each line of file can not be out of [N-1,N+1] where N
7325 is current frame number for @code{absolute} mode or out of [-1, 1] range
7326 for @code{relative} mode. First number tells from which frame to pick up top
7327 field and second number tells from which frame to pick up bottom field.
7329 If optionally followed by @code{+} output frame will be marked as interlaced,
7330 else if followed by @code{-} output frame will be marked as progressive, else
7331 it will be marked same as input frame.
7332 If line starts with @code{#} or @code{;} that line is skipped.
7335 Can be item @code{absolute} or @code{relative}. Default is @code{absolute}.
7338 Example of first several lines of @code{hint} file for @code{relative} mode:
7341 1,0 - # second frame, use third's frame top field and second's frame bottom field
7342 1,0 - # third frame, use fourth's frame top field and third's frame bottom field
7359 Field matching filter for inverse telecine. It is meant to reconstruct the
7360 progressive frames from a telecined stream. The filter does not drop duplicated
7361 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
7362 followed by a decimation filter such as @ref{decimate} in the filtergraph.
7364 The separation of the field matching and the decimation is notably motivated by
7365 the possibility of inserting a de-interlacing filter fallback between the two.
7366 If the source has mixed telecined and real interlaced content,
7367 @code{fieldmatch} will not be able to match fields for the interlaced parts.
7368 But these remaining combed frames will be marked as interlaced, and thus can be
7369 de-interlaced by a later filter such as @ref{yadif} before decimation.
7371 In addition to the various configuration options, @code{fieldmatch} can take an
7372 optional second stream, activated through the @option{ppsrc} option. If
7373 enabled, the frames reconstruction will be based on the fields and frames from
7374 this second stream. This allows the first input to be pre-processed in order to
7375 help the various algorithms of the filter, while keeping the output lossless
7376 (assuming the fields are matched properly). Typically, a field-aware denoiser,
7377 or brightness/contrast adjustments can help.
7379 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
7380 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
7381 which @code{fieldmatch} is based on. While the semantic and usage are very
7382 close, some behaviour and options names can differ.
7384 The @ref{decimate} filter currently only works for constant frame rate input.
7385 If your input has mixed telecined (30fps) and progressive content with a lower
7386 framerate like 24fps use the following filterchain to produce the necessary cfr
7387 stream: @code{dejudder,fps=30000/1001,fieldmatch,decimate}.
7389 The filter accepts the following options:
7393 Specify the assumed field order of the input stream. Available values are:
7397 Auto detect parity (use FFmpeg's internal parity value).
7399 Assume bottom field first.
7401 Assume top field first.
7404 Note that it is sometimes recommended not to trust the parity announced by the
7407 Default value is @var{auto}.
7410 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
7411 sense that it won't risk creating jerkiness due to duplicate frames when
7412 possible, but if there are bad edits or blended fields it will end up
7413 outputting combed frames when a good match might actually exist. On the other
7414 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
7415 but will almost always find a good frame if there is one. The other values are
7416 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
7417 jerkiness and creating duplicate frames versus finding good matches in sections
7418 with bad edits, orphaned fields, blended fields, etc.
7420 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
7422 Available values are:
7426 2-way matching (p/c)
7428 2-way matching, and trying 3rd match if still combed (p/c + n)
7430 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
7432 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
7433 still combed (p/c + n + u/b)
7435 3-way matching (p/c/n)
7437 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
7438 detected as combed (p/c/n + u/b)
7441 The parenthesis at the end indicate the matches that would be used for that
7442 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
7445 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
7448 Default value is @var{pc_n}.
7451 Mark the main input stream as a pre-processed input, and enable the secondary
7452 input stream as the clean source to pick the fields from. See the filter
7453 introduction for more details. It is similar to the @option{clip2} feature from
7456 Default value is @code{0} (disabled).
7459 Set the field to match from. It is recommended to set this to the same value as
7460 @option{order} unless you experience matching failures with that setting. In
7461 certain circumstances changing the field that is used to match from can have a
7462 large impact on matching performance. Available values are:
7466 Automatic (same value as @option{order}).
7468 Match from the bottom field.
7470 Match from the top field.
7473 Default value is @var{auto}.
7476 Set whether or not chroma is included during the match comparisons. In most
7477 cases it is recommended to leave this enabled. You should set this to @code{0}
7478 only if your clip has bad chroma problems such as heavy rainbowing or other
7479 artifacts. Setting this to @code{0} could also be used to speed things up at
7480 the cost of some accuracy.
7482 Default value is @code{1}.
7486 These define an exclusion band which excludes the lines between @option{y0} and
7487 @option{y1} from being included in the field matching decision. An exclusion
7488 band can be used to ignore subtitles, a logo, or other things that may
7489 interfere with the matching. @option{y0} sets the starting scan line and
7490 @option{y1} sets the ending line; all lines in between @option{y0} and
7491 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
7492 @option{y0} and @option{y1} to the same value will disable the feature.
7493 @option{y0} and @option{y1} defaults to @code{0}.
7496 Set the scene change detection threshold as a percentage of maximum change on
7497 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
7498 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
7499 @option{scthresh} is @code{[0.0, 100.0]}.
7501 Default value is @code{12.0}.
7504 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
7505 account the combed scores of matches when deciding what match to use as the
7506 final match. Available values are:
7510 No final matching based on combed scores.
7512 Combed scores are only used when a scene change is detected.
7514 Use combed scores all the time.
7517 Default is @var{sc}.
7520 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
7521 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
7522 Available values are:
7526 No forced calculation.
7528 Force p/c/n calculations.
7530 Force p/c/n/u/b calculations.
7533 Default value is @var{none}.
7536 This is the area combing threshold used for combed frame detection. This
7537 essentially controls how "strong" or "visible" combing must be to be detected.
7538 Larger values mean combing must be more visible and smaller values mean combing
7539 can be less visible or strong and still be detected. Valid settings are from
7540 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
7541 be detected as combed). This is basically a pixel difference value. A good
7542 range is @code{[8, 12]}.
7544 Default value is @code{9}.
7547 Sets whether or not chroma is considered in the combed frame decision. Only
7548 disable this if your source has chroma problems (rainbowing, etc.) that are
7549 causing problems for the combed frame detection with chroma enabled. Actually,
7550 using @option{chroma}=@var{0} is usually more reliable, except for the case
7551 where there is chroma only combing in the source.
7553 Default value is @code{0}.
7557 Respectively set the x-axis and y-axis size of the window used during combed
7558 frame detection. This has to do with the size of the area in which
7559 @option{combpel} pixels are required to be detected as combed for a frame to be
7560 declared combed. See the @option{combpel} parameter description for more info.
7561 Possible values are any number that is a power of 2 starting at 4 and going up
7564 Default value is @code{16}.
7567 The number of combed pixels inside any of the @option{blocky} by
7568 @option{blockx} size blocks on the frame for the frame to be detected as
7569 combed. While @option{cthresh} controls how "visible" the combing must be, this
7570 setting controls "how much" combing there must be in any localized area (a
7571 window defined by the @option{blockx} and @option{blocky} settings) on the
7572 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
7573 which point no frames will ever be detected as combed). This setting is known
7574 as @option{MI} in TFM/VFM vocabulary.
7576 Default value is @code{80}.
7579 @anchor{p/c/n/u/b meaning}
7580 @subsection p/c/n/u/b meaning
7582 @subsubsection p/c/n
7584 We assume the following telecined stream:
7587 Top fields: 1 2 2 3 4
7588 Bottom fields: 1 2 3 4 4
7591 The numbers correspond to the progressive frame the fields relate to. Here, the
7592 first two frames are progressive, the 3rd and 4th are combed, and so on.
7594 When @code{fieldmatch} is configured to run a matching from bottom
7595 (@option{field}=@var{bottom}) this is how this input stream get transformed:
7600 B 1 2 3 4 4 <-- matching reference
7609 As a result of the field matching, we can see that some frames get duplicated.
7610 To perform a complete inverse telecine, you need to rely on a decimation filter
7611 after this operation. See for instance the @ref{decimate} filter.
7613 The same operation now matching from top fields (@option{field}=@var{top})
7618 T 1 2 2 3 4 <-- matching reference
7628 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
7629 basically, they refer to the frame and field of the opposite parity:
7632 @item @var{p} matches the field of the opposite parity in the previous frame
7633 @item @var{c} matches the field of the opposite parity in the current frame
7634 @item @var{n} matches the field of the opposite parity in the next frame
7639 The @var{u} and @var{b} matching are a bit special in the sense that they match
7640 from the opposite parity flag. In the following examples, we assume that we are
7641 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
7642 'x' is placed above and below each matched fields.
7644 With bottom matching (@option{field}=@var{bottom}):
7649 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
7650 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
7658 With top matching (@option{field}=@var{top}):
7663 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
7664 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
7672 @subsection Examples
7674 Simple IVTC of a top field first telecined stream:
7676 fieldmatch=order=tff:combmatch=none, decimate
7679 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
7681 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
7686 Transform the field order of the input video.
7688 It accepts the following parameters:
7693 The output field order. Valid values are @var{tff} for top field first or @var{bff}
7694 for bottom field first.
7697 The default value is @samp{tff}.
7699 The transformation is done by shifting the picture content up or down
7700 by one line, and filling the remaining line with appropriate picture content.
7701 This method is consistent with most broadcast field order converters.
7703 If the input video is not flagged as being interlaced, or it is already
7704 flagged as being of the required output field order, then this filter does
7705 not alter the incoming video.
7707 It is very useful when converting to or from PAL DV material,
7708 which is bottom field first.
7712 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
7715 @section fifo, afifo
7717 Buffer input images and send them when they are requested.
7719 It is mainly useful when auto-inserted by the libavfilter
7722 It does not take parameters.
7726 Find a rectangular object
7728 It accepts the following options:
7732 Filepath of the object image, needs to be in gray8.
7735 Detection threshold, default is 0.5.
7738 Number of mipmaps, default is 3.
7740 @item xmin, ymin, xmax, ymax
7741 Specifies the rectangle in which to search.
7744 @subsection Examples
7748 Generate a representative palette of a given video using @command{ffmpeg}:
7750 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
7756 Cover a rectangular object
7758 It accepts the following options:
7762 Filepath of the optional cover image, needs to be in yuv420.
7767 It accepts the following values:
7770 cover it by the supplied image
7772 cover it by interpolating the surrounding pixels
7775 Default value is @var{blur}.
7778 @subsection Examples
7782 Generate a representative palette of a given video using @command{ffmpeg}:
7784 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
7791 Convert the input video to one of the specified pixel formats.
7792 Libavfilter will try to pick one that is suitable as input to
7795 It accepts the following parameters:
7799 A '|'-separated list of pixel format names, such as
7800 "pix_fmts=yuv420p|monow|rgb24".
7804 @subsection Examples
7808 Convert the input video to the @var{yuv420p} format
7810 format=pix_fmts=yuv420p
7813 Convert the input video to any of the formats in the list
7815 format=pix_fmts=yuv420p|yuv444p|yuv410p
7822 Convert the video to specified constant frame rate by duplicating or dropping
7823 frames as necessary.
7825 It accepts the following parameters:
7829 The desired output frame rate. The default is @code{25}.
7834 Possible values are:
7837 zero round towards 0
7841 round towards -infinity
7843 round towards +infinity
7847 The default is @code{near}.
7850 Assume the first PTS should be the given value, in seconds. This allows for
7851 padding/trimming at the start of stream. By default, no assumption is made
7852 about the first frame's expected PTS, so no padding or trimming is done.
7853 For example, this could be set to 0 to pad the beginning with duplicates of
7854 the first frame if a video stream starts after the audio stream or to trim any
7855 frames with a negative PTS.
7859 Alternatively, the options can be specified as a flat string:
7860 @var{fps}[:@var{round}].
7862 See also the @ref{setpts} filter.
7864 @subsection Examples
7868 A typical usage in order to set the fps to 25:
7874 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
7876 fps=fps=film:round=near
7882 Pack two different video streams into a stereoscopic video, setting proper
7883 metadata on supported codecs. The two views should have the same size and
7884 framerate and processing will stop when the shorter video ends. Please note
7885 that you may conveniently adjust view properties with the @ref{scale} and
7888 It accepts the following parameters:
7892 The desired packing format. Supported values are:
7897 The views are next to each other (default).
7900 The views are on top of each other.
7903 The views are packed by line.
7906 The views are packed by column.
7909 The views are temporally interleaved.
7918 # Convert left and right views into a frame-sequential video
7919 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
7921 # Convert views into a side-by-side video with the same output resolution as the input
7922 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
7927 Change the frame rate by interpolating new video output frames from the source
7930 This filter is not designed to function correctly with interlaced media. If
7931 you wish to change the frame rate of interlaced media then you are required
7932 to deinterlace before this filter and re-interlace after this filter.
7934 A description of the accepted options follows.
7938 Specify the output frames per second. This option can also be specified
7939 as a value alone. The default is @code{50}.
7942 Specify the start of a range where the output frame will be created as a
7943 linear interpolation of two frames. The range is [@code{0}-@code{255}],
7944 the default is @code{15}.
7947 Specify the end of a range where the output frame will be created as a
7948 linear interpolation of two frames. The range is [@code{0}-@code{255}],
7949 the default is @code{240}.
7952 Specify the level at which a scene change is detected as a value between
7953 0 and 100 to indicate a new scene; a low value reflects a low
7954 probability for the current frame to introduce a new scene, while a higher
7955 value means the current frame is more likely to be one.
7956 The default is @code{7}.
7959 Specify flags influencing the filter process.
7961 Available value for @var{flags} is:
7964 @item scene_change_detect, scd
7965 Enable scene change detection using the value of the option @var{scene}.
7966 This flag is enabled by default.
7972 Select one frame every N-th frame.
7974 This filter accepts the following option:
7977 Select frame after every @code{step} frames.
7978 Allowed values are positive integers higher than 0. Default value is @code{1}.
7984 Apply a frei0r effect to the input video.
7986 To enable the compilation of this filter, you need to install the frei0r
7987 header and configure FFmpeg with @code{--enable-frei0r}.
7989 It accepts the following parameters:
7994 The name of the frei0r effect to load. If the environment variable
7995 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
7996 directories specified by the colon-separated list in @env{FREIOR_PATH}.
7997 Otherwise, the standard frei0r paths are searched, in this order:
7998 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
7999 @file{/usr/lib/frei0r-1/}.
8002 A '|'-separated list of parameters to pass to the frei0r effect.
8006 A frei0r effect parameter can be a boolean (its value is either
8007 "y" or "n"), a double, a color (specified as
8008 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
8009 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
8010 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
8011 @var{X} and @var{Y} are floating point numbers) and/or a string.
8013 The number and types of parameters depend on the loaded effect. If an
8014 effect parameter is not specified, the default value is set.
8016 @subsection Examples
8020 Apply the distort0r effect, setting the first two double parameters:
8022 frei0r=filter_name=distort0r:filter_params=0.5|0.01
8026 Apply the colordistance effect, taking a color as the first parameter:
8028 frei0r=colordistance:0.2/0.3/0.4
8029 frei0r=colordistance:violet
8030 frei0r=colordistance:0x112233
8034 Apply the perspective effect, specifying the top left and top right image
8037 frei0r=perspective:0.2/0.2|0.8/0.2
8041 For more information, see
8042 @url{http://frei0r.dyne.org}
8046 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
8048 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
8049 processing filter, one of them is performed once per block, not per pixel.
8050 This allows for much higher speed.
8052 The filter accepts the following options:
8056 Set quality. This option defines the number of levels for averaging. It accepts
8057 an integer in the range 4-5. Default value is @code{4}.
8060 Force a constant quantization parameter. It accepts an integer in range 0-63.
8061 If not set, the filter will use the QP from the video stream (if available).
8064 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
8065 more details but also more artifacts, while higher values make the image smoother
8066 but also blurrier. Default value is @code{0} − PSNR optimal.
8069 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8070 option may cause flicker since the B-Frames have often larger QP. Default is
8071 @code{0} (not enabled).
8077 The filter accepts the following options:
8081 Set the luminance expression.
8083 Set the chrominance blue expression.
8085 Set the chrominance red expression.
8087 Set the alpha expression.
8089 Set the red expression.
8091 Set the green expression.
8093 Set the blue expression.
8096 The colorspace is selected according to the specified options. If one
8097 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
8098 options is specified, the filter will automatically select a YCbCr
8099 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
8100 @option{blue_expr} options is specified, it will select an RGB
8103 If one of the chrominance expression is not defined, it falls back on the other
8104 one. If no alpha expression is specified it will evaluate to opaque value.
8105 If none of chrominance expressions are specified, they will evaluate
8106 to the luminance expression.
8108 The expressions can use the following variables and functions:
8112 The sequential number of the filtered frame, starting from @code{0}.
8116 The coordinates of the current sample.
8120 The width and height of the image.
8124 Width and height scale depending on the currently filtered plane. It is the
8125 ratio between the corresponding luma plane number of pixels and the current
8126 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
8127 @code{0.5,0.5} for chroma planes.
8130 Time of the current frame, expressed in seconds.
8133 Return the value of the pixel at location (@var{x},@var{y}) of the current
8137 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
8141 Return the value of the pixel at location (@var{x},@var{y}) of the
8142 blue-difference chroma plane. Return 0 if there is no such plane.
8145 Return the value of the pixel at location (@var{x},@var{y}) of the
8146 red-difference chroma plane. Return 0 if there is no such plane.
8151 Return the value of the pixel at location (@var{x},@var{y}) of the
8152 red/green/blue component. Return 0 if there is no such component.
8155 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
8156 plane. Return 0 if there is no such plane.
8159 For functions, if @var{x} and @var{y} are outside the area, the value will be
8160 automatically clipped to the closer edge.
8162 @subsection Examples
8166 Flip the image horizontally:
8172 Generate a bidimensional sine wave, with angle @code{PI/3} and a
8173 wavelength of 100 pixels:
8175 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
8179 Generate a fancy enigmatic moving light:
8181 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
8185 Generate a quick emboss effect:
8187 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
8191 Modify RGB components depending on pixel position:
8193 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
8197 Create a radial gradient that is the same size as the input (also see
8198 the @ref{vignette} filter):
8200 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
8206 Fix the banding artifacts that are sometimes introduced into nearly flat
8207 regions by truncation to 8bit color depth.
8208 Interpolate the gradients that should go where the bands are, and
8211 It is designed for playback only. Do not use it prior to
8212 lossy compression, because compression tends to lose the dither and
8213 bring back the bands.
8215 It accepts the following parameters:
8220 The maximum amount by which the filter will change any one pixel. This is also
8221 the threshold for detecting nearly flat regions. Acceptable values range from
8222 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
8226 The neighborhood to fit the gradient to. A larger radius makes for smoother
8227 gradients, but also prevents the filter from modifying the pixels near detailed
8228 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
8229 values will be clipped to the valid range.
8233 Alternatively, the options can be specified as a flat string:
8234 @var{strength}[:@var{radius}]
8236 @subsection Examples
8240 Apply the filter with a @code{3.5} strength and radius of @code{8}:
8246 Specify radius, omitting the strength (which will fall-back to the default
8257 Apply a Hald CLUT to a video stream.
8259 First input is the video stream to process, and second one is the Hald CLUT.
8260 The Hald CLUT input can be a simple picture or a complete video stream.
8262 The filter accepts the following options:
8266 Force termination when the shortest input terminates. Default is @code{0}.
8268 Continue applying the last CLUT after the end of the stream. A value of
8269 @code{0} disable the filter after the last frame of the CLUT is reached.
8270 Default is @code{1}.
8273 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
8274 filters share the same internals).
8276 More information about the Hald CLUT can be found on Eskil Steenberg's website
8277 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
8279 @subsection Workflow examples
8281 @subsubsection Hald CLUT video stream
8283 Generate an identity Hald CLUT stream altered with various effects:
8285 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
8288 Note: make sure you use a lossless codec.
8290 Then use it with @code{haldclut} to apply it on some random stream:
8292 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
8295 The Hald CLUT will be applied to the 10 first seconds (duration of
8296 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
8297 to the remaining frames of the @code{mandelbrot} stream.
8299 @subsubsection Hald CLUT with preview
8301 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
8302 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
8303 biggest possible square starting at the top left of the picture. The remaining
8304 padding pixels (bottom or right) will be ignored. This area can be used to add
8305 a preview of the Hald CLUT.
8307 Typically, the following generated Hald CLUT will be supported by the
8308 @code{haldclut} filter:
8311 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
8312 pad=iw+320 [padded_clut];
8313 smptebars=s=320x256, split [a][b];
8314 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
8315 [main][b] overlay=W-320" -frames:v 1 clut.png
8318 It contains the original and a preview of the effect of the CLUT: SMPTE color
8319 bars are displayed on the right-top, and below the same color bars processed by
8322 Then, the effect of this Hald CLUT can be visualized with:
8324 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
8329 Decodes high definition audio cd data. 16-Bit PCM stream containing hdcd flags
8330 is converted to 20-bit PCM stream.
8334 Flip the input video horizontally.
8336 For example, to horizontally flip the input video with @command{ffmpeg}:
8338 ffmpeg -i in.avi -vf "hflip" out.avi
8342 This filter applies a global color histogram equalization on a
8345 It can be used to correct video that has a compressed range of pixel
8346 intensities. The filter redistributes the pixel intensities to
8347 equalize their distribution across the intensity range. It may be
8348 viewed as an "automatically adjusting contrast filter". This filter is
8349 useful only for correcting degraded or poorly captured source
8352 The filter accepts the following options:
8356 Determine the amount of equalization to be applied. As the strength
8357 is reduced, the distribution of pixel intensities more-and-more
8358 approaches that of the input frame. The value must be a float number
8359 in the range [0,1] and defaults to 0.200.
8362 Set the maximum intensity that can generated and scale the output
8363 values appropriately. The strength should be set as desired and then
8364 the intensity can be limited if needed to avoid washing-out. The value
8365 must be a float number in the range [0,1] and defaults to 0.210.
8368 Set the antibanding level. If enabled the filter will randomly vary
8369 the luminance of output pixels by a small amount to avoid banding of
8370 the histogram. Possible values are @code{none}, @code{weak} or
8371 @code{strong}. It defaults to @code{none}.
8376 Compute and draw a color distribution histogram for the input video.
8378 The computed histogram is a representation of the color component
8379 distribution in an image.
8381 Standard histogram displays the color components distribution in an image.
8382 Displays color graph for each color component. Shows distribution of
8383 the Y, U, V, A or R, G, B components, depending on input format, in the
8384 current frame. Below each graph a color component scale meter is shown.
8386 The filter accepts the following options:
8390 Set height of level. Default value is @code{200}.
8391 Allowed range is [50, 2048].
8394 Set height of color scale. Default value is @code{12}.
8395 Allowed range is [0, 40].
8399 It accepts the following values:
8402 Per color component graphs are placed below each other.
8405 Presents information identical to that in the @code{parade}, except
8406 that the graphs representing color components are superimposed directly
8409 Default is @code{parade}.
8412 Set mode. Can be either @code{linear}, or @code{logarithmic}.
8413 Default is @code{linear}.
8416 Set what color components to display.
8417 Default is @code{7}.
8420 @subsection Examples
8425 Calculate and draw histogram:
8427 ffplay -i input -vf histogram
8435 This is a high precision/quality 3d denoise filter. It aims to reduce
8436 image noise, producing smooth images and making still images really
8437 still. It should enhance compressibility.
8439 It accepts the following optional parameters:
8443 A non-negative floating point number which specifies spatial luma strength.
8446 @item chroma_spatial
8447 A non-negative floating point number which specifies spatial chroma strength.
8448 It defaults to 3.0*@var{luma_spatial}/4.0.
8451 A floating point number which specifies luma temporal strength. It defaults to
8452 6.0*@var{luma_spatial}/4.0.
8455 A floating point number which specifies chroma temporal strength. It defaults to
8456 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
8459 @anchor{hwupload_cuda}
8460 @section hwupload_cuda
8462 Upload system memory frames to a CUDA device.
8464 It accepts the following optional parameters:
8468 The number of the CUDA device to use
8473 Apply a high-quality magnification filter designed for pixel art. This filter
8474 was originally created by Maxim Stepin.
8476 It accepts the following option:
8480 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
8481 @code{hq3x} and @code{4} for @code{hq4x}.
8482 Default is @code{3}.
8486 Stack input videos horizontally.
8488 All streams must be of same pixel format and of same height.
8490 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
8491 to create same output.
8493 The filter accept the following option:
8497 Set number of input streams. Default is 2.
8500 If set to 1, force the output to terminate when the shortest input
8501 terminates. Default value is 0.
8506 Modify the hue and/or the saturation of the input.
8508 It accepts the following parameters:
8512 Specify the hue angle as a number of degrees. It accepts an expression,
8513 and defaults to "0".
8516 Specify the saturation in the [-10,10] range. It accepts an expression and
8520 Specify the hue angle as a number of radians. It accepts an
8521 expression, and defaults to "0".
8524 Specify the brightness in the [-10,10] range. It accepts an expression and
8528 @option{h} and @option{H} are mutually exclusive, and can't be
8529 specified at the same time.
8531 The @option{b}, @option{h}, @option{H} and @option{s} option values are
8532 expressions containing the following constants:
8536 frame count of the input frame starting from 0
8539 presentation timestamp of the input frame expressed in time base units
8542 frame rate of the input video, NAN if the input frame rate is unknown
8545 timestamp expressed in seconds, NAN if the input timestamp is unknown
8548 time base of the input video
8551 @subsection Examples
8555 Set the hue to 90 degrees and the saturation to 1.0:
8561 Same command but expressing the hue in radians:
8567 Rotate hue and make the saturation swing between 0
8568 and 2 over a period of 1 second:
8570 hue="H=2*PI*t: s=sin(2*PI*t)+1"
8574 Apply a 3 seconds saturation fade-in effect starting at 0:
8579 The general fade-in expression can be written as:
8581 hue="s=min(0\, max((t-START)/DURATION\, 1))"
8585 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
8587 hue="s=max(0\, min(1\, (8-t)/3))"
8590 The general fade-out expression can be written as:
8592 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
8597 @subsection Commands
8599 This filter supports the following commands:
8605 Modify the hue and/or the saturation and/or brightness of the input video.
8606 The command accepts the same syntax of the corresponding option.
8608 If the specified expression is not valid, it is kept at its current
8614 Detect video interlacing type.
8616 This filter tries to detect if the input frames as interlaced, progressive,
8617 top or bottom field first. It will also try and detect fields that are
8618 repeated between adjacent frames (a sign of telecine).
8620 Single frame detection considers only immediately adjacent frames when classifying each frame.
8621 Multiple frame detection incorporates the classification history of previous frames.
8623 The filter will log these metadata values:
8626 @item single.current_frame
8627 Detected type of current frame using single-frame detection. One of:
8628 ``tff'' (top field first), ``bff'' (bottom field first),
8629 ``progressive'', or ``undetermined''
8632 Cumulative number of frames detected as top field first using single-frame detection.
8635 Cumulative number of frames detected as top field first using multiple-frame detection.
8638 Cumulative number of frames detected as bottom field first using single-frame detection.
8640 @item multiple.current_frame
8641 Detected type of current frame using multiple-frame detection. One of:
8642 ``tff'' (top field first), ``bff'' (bottom field first),
8643 ``progressive'', or ``undetermined''
8646 Cumulative number of frames detected as bottom field first using multiple-frame detection.
8648 @item single.progressive
8649 Cumulative number of frames detected as progressive using single-frame detection.
8651 @item multiple.progressive
8652 Cumulative number of frames detected as progressive using multiple-frame detection.
8654 @item single.undetermined
8655 Cumulative number of frames that could not be classified using single-frame detection.
8657 @item multiple.undetermined
8658 Cumulative number of frames that could not be classified using multiple-frame detection.
8660 @item repeated.current_frame
8661 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
8663 @item repeated.neither
8664 Cumulative number of frames with no repeated field.
8667 Cumulative number of frames with the top field repeated from the previous frame's top field.
8669 @item repeated.bottom
8670 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
8673 The filter accepts the following options:
8677 Set interlacing threshold.
8679 Set progressive threshold.
8681 Threshold for repeated field detection.
8683 Number of frames after which a given frame's contribution to the
8684 statistics is halved (i.e., it contributes only 0.5 to it's
8685 classification). The default of 0 means that all frames seen are given
8686 full weight of 1.0 forever.
8687 @item analyze_interlaced_flag
8688 When this is not 0 then idet will use the specified number of frames to determine
8689 if the interlaced flag is accurate, it will not count undetermined frames.
8690 If the flag is found to be accurate it will be used without any further
8691 computations, if it is found to be inaccurate it will be cleared without any
8692 further computations. This allows inserting the idet filter as a low computational
8693 method to clean up the interlaced flag
8698 Deinterleave or interleave fields.
8700 This filter allows one to process interlaced images fields without
8701 deinterlacing them. Deinterleaving splits the input frame into 2
8702 fields (so called half pictures). Odd lines are moved to the top
8703 half of the output image, even lines to the bottom half.
8704 You can process (filter) them independently and then re-interleave them.
8706 The filter accepts the following options:
8710 @item chroma_mode, c
8712 Available values for @var{luma_mode}, @var{chroma_mode} and
8713 @var{alpha_mode} are:
8719 @item deinterleave, d
8720 Deinterleave fields, placing one above the other.
8723 Interleave fields. Reverse the effect of deinterleaving.
8725 Default value is @code{none}.
8728 @item chroma_swap, cs
8729 @item alpha_swap, as
8730 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
8735 Apply inflate effect to the video.
8737 This filter replaces the pixel by the local(3x3) average by taking into account
8738 only values higher than the pixel.
8740 It accepts the following options:
8747 Limit the maximum change for each plane, default is 65535.
8748 If 0, plane will remain unchanged.
8753 Simple interlacing filter from progressive contents. This interleaves upper (or
8754 lower) lines from odd frames with lower (or upper) lines from even frames,
8755 halving the frame rate and preserving image height.
8758 Original Original New Frame
8759 Frame 'j' Frame 'j+1' (tff)
8760 ========== =========== ==================
8761 Line 0 --------------------> Frame 'j' Line 0
8762 Line 1 Line 1 ----> Frame 'j+1' Line 1
8763 Line 2 ---------------------> Frame 'j' Line 2
8764 Line 3 Line 3 ----> Frame 'j+1' Line 3
8766 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
8769 It accepts the following optional parameters:
8773 This determines whether the interlaced frame is taken from the even
8774 (tff - default) or odd (bff) lines of the progressive frame.
8777 Enable (default) or disable the vertical lowpass filter to avoid twitter
8778 interlacing and reduce moire patterns.
8783 Deinterlace input video by applying Donald Graft's adaptive kernel
8784 deinterling. Work on interlaced parts of a video to produce
8787 The description of the accepted parameters follows.
8791 Set the threshold which affects the filter's tolerance when
8792 determining if a pixel line must be processed. It must be an integer
8793 in the range [0,255] and defaults to 10. A value of 0 will result in
8794 applying the process on every pixels.
8797 Paint pixels exceeding the threshold value to white if set to 1.
8801 Set the fields order. Swap fields if set to 1, leave fields alone if
8805 Enable additional sharpening if set to 1. Default is 0.
8808 Enable twoway sharpening if set to 1. Default is 0.
8811 @subsection Examples
8815 Apply default values:
8817 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
8821 Enable additional sharpening:
8827 Paint processed pixels in white:
8833 @section lenscorrection
8835 Correct radial lens distortion
8837 This filter can be used to correct for radial distortion as can result from the use
8838 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
8839 one can use tools available for example as part of opencv or simply trial-and-error.
8840 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
8841 and extract the k1 and k2 coefficients from the resulting matrix.
8843 Note that effectively the same filter is available in the open-source tools Krita and
8844 Digikam from the KDE project.
8846 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
8847 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
8848 brightness distribution, so you may want to use both filters together in certain
8849 cases, though you will have to take care of ordering, i.e. whether vignetting should
8850 be applied before or after lens correction.
8854 The filter accepts the following options:
8858 Relative x-coordinate of the focal point of the image, and thereby the center of the
8859 distortion. This value has a range [0,1] and is expressed as fractions of the image
8862 Relative y-coordinate of the focal point of the image, and thereby the center of the
8863 distortion. This value has a range [0,1] and is expressed as fractions of the image
8866 Coefficient of the quadratic correction term. 0.5 means no correction.
8868 Coefficient of the double quadratic correction term. 0.5 means no correction.
8871 The formula that generates the correction is:
8873 @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)
8875 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
8876 distances from the focal point in the source and target images, respectively.
8878 @section loop, aloop
8880 Loop video frames or audio samples.
8882 Those filters accepts the following options:
8886 Set the number of loops.
8889 Set maximal size in number of frames for @code{loop} filter or maximal number
8890 of samples in case of @code{aloop} filter.
8893 Set first frame of loop for @code{loop} filter or first sample of loop in case
8894 of @code{aloop} filter.
8900 Apply a 3D LUT to an input video.
8902 The filter accepts the following options:
8906 Set the 3D LUT file name.
8908 Currently supported formats:
8920 Select interpolation mode.
8922 Available values are:
8926 Use values from the nearest defined point.
8928 Interpolate values using the 8 points defining a cube.
8930 Interpolate values using a tetrahedron.
8934 @section lut, lutrgb, lutyuv
8936 Compute a look-up table for binding each pixel component input value
8937 to an output value, and apply it to the input video.
8939 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
8940 to an RGB input video.
8942 These filters accept the following parameters:
8945 set first pixel component expression
8947 set second pixel component expression
8949 set third pixel component expression
8951 set fourth pixel component expression, corresponds to the alpha component
8954 set red component expression
8956 set green component expression
8958 set blue component expression
8960 alpha component expression
8963 set Y/luminance component expression
8965 set U/Cb component expression
8967 set V/Cr component expression
8970 Each of them specifies the expression to use for computing the lookup table for
8971 the corresponding pixel component values.
8973 The exact component associated to each of the @var{c*} options depends on the
8976 The @var{lut} filter requires either YUV or RGB pixel formats in input,
8977 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
8979 The expressions can contain the following constants and functions:
8984 The input width and height.
8987 The input value for the pixel component.
8990 The input value, clipped to the @var{minval}-@var{maxval} range.
8993 The maximum value for the pixel component.
8996 The minimum value for the pixel component.
8999 The negated value for the pixel component value, clipped to the
9000 @var{minval}-@var{maxval} range; it corresponds to the expression
9001 "maxval-clipval+minval".
9004 The computed value in @var{val}, clipped to the
9005 @var{minval}-@var{maxval} range.
9007 @item gammaval(gamma)
9008 The computed gamma correction value of the pixel component value,
9009 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
9011 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
9015 All expressions default to "val".
9017 @subsection Examples
9023 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
9024 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
9027 The above is the same as:
9029 lutrgb="r=negval:g=negval:b=negval"
9030 lutyuv="y=negval:u=negval:v=negval"
9040 Remove chroma components, turning the video into a graytone image:
9042 lutyuv="u=128:v=128"
9046 Apply a luma burning effect:
9052 Remove green and blue components:
9058 Set a constant alpha channel value on input:
9060 format=rgba,lutrgb=a="maxval-minval/2"
9064 Correct luminance gamma by a factor of 0.5:
9066 lutyuv=y=gammaval(0.5)
9070 Discard least significant bits of luma:
9072 lutyuv=y='bitand(val, 128+64+32)'
9076 @section maskedmerge
9078 Merge the first input stream with the second input stream using per pixel
9079 weights in the third input stream.
9081 A value of 0 in the third stream pixel component means that pixel component
9082 from first stream is returned unchanged, while maximum value (eg. 255 for
9083 8-bit videos) means that pixel component from second stream is returned
9084 unchanged. Intermediate values define the amount of merging between both
9085 input stream's pixel components.
9087 This filter accepts the following options:
9090 Set which planes will be processed as bitmap, unprocessed planes will be
9091 copied from first stream.
9092 By default value 0xf, all planes will be processed.
9097 Apply motion-compensation deinterlacing.
9099 It needs one field per frame as input and must thus be used together
9100 with yadif=1/3 or equivalent.
9102 This filter accepts the following options:
9105 Set the deinterlacing mode.
9107 It accepts one of the following values:
9112 use iterative motion estimation
9114 like @samp{slow}, but use multiple reference frames.
9116 Default value is @samp{fast}.
9119 Set the picture field parity assumed for the input video. It must be
9120 one of the following values:
9124 assume top field first
9126 assume bottom field first
9129 Default value is @samp{bff}.
9132 Set per-block quantization parameter (QP) used by the internal
9135 Higher values should result in a smoother motion vector field but less
9136 optimal individual vectors. Default value is 1.
9139 @section mergeplanes
9141 Merge color channel components from several video streams.
9143 The filter accepts up to 4 input streams, and merge selected input
9144 planes to the output video.
9146 This filter accepts the following options:
9149 Set input to output plane mapping. Default is @code{0}.
9151 The mappings is specified as a bitmap. It should be specified as a
9152 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
9153 mapping for the first plane of the output stream. 'A' sets the number of
9154 the input stream to use (from 0 to 3), and 'a' the plane number of the
9155 corresponding input to use (from 0 to 3). The rest of the mappings is
9156 similar, 'Bb' describes the mapping for the output stream second
9157 plane, 'Cc' describes the mapping for the output stream third plane and
9158 'Dd' describes the mapping for the output stream fourth plane.
9161 Set output pixel format. Default is @code{yuva444p}.
9164 @subsection Examples
9168 Merge three gray video streams of same width and height into single video stream:
9170 [a0][a1][a2]mergeplanes=0x001020:yuv444p
9174 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
9176 [a0][a1]mergeplanes=0x00010210:yuva444p
9180 Swap Y and A plane in yuva444p stream:
9182 format=yuva444p,mergeplanes=0x03010200:yuva444p
9186 Swap U and V plane in yuv420p stream:
9188 format=yuv420p,mergeplanes=0x000201:yuv420p
9192 Cast a rgb24 clip to yuv444p:
9194 format=rgb24,mergeplanes=0x000102:yuv444p
9198 @section metadata, ametadata
9200 Manipulate frame metadata.
9202 This filter accepts the following options:
9206 Set mode of operation of the filter.
9208 Can be one of the following:
9212 If both @code{value} and @code{key} is set, select frames
9213 which have such metadata. If only @code{key} is set, select
9214 every frame that has such key in metadata.
9217 Add new metadata @code{key} and @code{value}. If key is already available
9221 Modify value of already present key.
9224 If @code{value} is set, delete only keys that have such value.
9225 Otherwise, delete key.
9228 Print key and its value if metadata was found. If @code{key} is not set print all
9229 metadata values available in frame.
9233 Set key used with all modes. Must be set for all modes except @code{print}.
9236 Set metadata value which will be used. This option is mandatory for
9237 @code{modify} and @code{add} mode.
9240 Which function to use when comparing metadata value and @code{value}.
9242 Can be one of following:
9246 Values are interpreted as strings, returns true if metadata value is same as @code{value}.
9249 Values are interpreted as strings, returns true if metadata value starts with
9250 the @code{value} option string.
9253 Values are interpreted as floats, returns true if metadata value is less than @code{value}.
9256 Values are interpreted as floats, returns true if @code{value} is equal with metadata value.
9259 Values are interpreted as floats, returns true if metadata value is greater than @code{value}.
9262 Values are interpreted as floats, returns true if expression from option @code{expr}
9267 Set expression which is used when @code{function} is set to @code{expr}.
9268 The expression is evaluated through the eval API and can contain the following
9273 Float representation of @code{value} from metadata key.
9276 Float representation of @code{value} as supplied by user in @code{value} option.
9280 If specified in @code{print} mode, output is written to the named file. When
9281 filename equals "-" data is written to standard output.
9282 If @code{file} option is not set, output is written to the log with AV_LOG_INFO
9286 @subsection Examples
9290 Print all metadata values for frames with key @code{lavfi.singnalstats.YDIF} with values
9294 signalstats,metadata=print:key=lavfi.signalstats.YDIF:value=0:function=expr:expr='between(VALUE1,0,1)'
9299 Drop frames that do not differ greatly from the previous frame in
9300 order to reduce frame rate.
9302 The main use of this filter is for very-low-bitrate encoding
9303 (e.g. streaming over dialup modem), but it could in theory be used for
9304 fixing movies that were inverse-telecined incorrectly.
9306 A description of the accepted options follows.
9310 Set the maximum number of consecutive frames which can be dropped (if
9311 positive), or the minimum interval between dropped frames (if
9312 negative). If the value is 0, the frame is dropped unregarding the
9313 number of previous sequentially dropped frames.
9320 Set the dropping threshold values.
9322 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
9323 represent actual pixel value differences, so a threshold of 64
9324 corresponds to 1 unit of difference for each pixel, or the same spread
9325 out differently over the block.
9327 A frame is a candidate for dropping if no 8x8 blocks differ by more
9328 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
9329 meaning the whole image) differ by more than a threshold of @option{lo}.
9331 Default value for @option{hi} is 64*12, default value for @option{lo} is
9332 64*5, and default value for @option{frac} is 0.33.
9340 It accepts an integer in input; if non-zero it negates the
9341 alpha component (if available). The default value in input is 0.
9345 Deinterlace video using neural network edge directed interpolation.
9347 This filter accepts the following options:
9351 Mandatory option, without binary file filter can not work.
9352 Currently file can be found here:
9353 https://github.com/dubhater/vapoursynth-nnedi3/blob/master/src/nnedi3_weights.bin
9356 Set which frames to deinterlace, by default it is @code{all}.
9357 Can be @code{all} or @code{interlaced}.
9360 Set mode of operation.
9362 Can be one of the following:
9366 Use frame flags, both fields.
9368 Use frame flags, single field.
9372 Use bottom field only.
9374 Use both fields, top first.
9376 Use both fields, bottom first.
9380 Set which planes to process, by default filter process all frames.
9383 Set size of local neighborhood around each pixel, used by the predictor neural
9386 Can be one of the following:
9399 Set the number of neurons in predicctor neural network.
9400 Can be one of the following:
9411 Controls the number of different neural network predictions that are blended
9412 together to compute the final output value. Can be @code{fast}, default or
9416 Set which set of weights to use in the predictor.
9417 Can be one of the following:
9421 weights trained to minimize absolute error
9423 weights trained to minimize squared error
9427 Controls whether or not the prescreener neural network is used to decide
9428 which pixels should be processed by the predictor neural network and which
9429 can be handled by simple cubic interpolation.
9430 The prescreener is trained to know whether cubic interpolation will be
9431 sufficient for a pixel or whether it should be predicted by the predictor nn.
9432 The computational complexity of the prescreener nn is much less than that of
9433 the predictor nn. Since most pixels can be handled by cubic interpolation,
9434 using the prescreener generally results in much faster processing.
9435 The prescreener is pretty accurate, so the difference between using it and not
9436 using it is almost always unnoticeable.
9438 Can be one of the following:
9446 Default is @code{new}.
9449 Set various debugging flags.
9454 Force libavfilter not to use any of the specified pixel formats for the
9455 input to the next filter.
9457 It accepts the following parameters:
9461 A '|'-separated list of pixel format names, such as
9462 apix_fmts=yuv420p|monow|rgb24".
9466 @subsection Examples
9470 Force libavfilter to use a format different from @var{yuv420p} for the
9471 input to the vflip filter:
9473 noformat=pix_fmts=yuv420p,vflip
9477 Convert the input video to any of the formats not contained in the list:
9479 noformat=yuv420p|yuv444p|yuv410p
9485 Add noise on video input frame.
9487 The filter accepts the following options:
9495 Set noise seed for specific pixel component or all pixel components in case
9496 of @var{all_seed}. Default value is @code{123457}.
9498 @item all_strength, alls
9499 @item c0_strength, c0s
9500 @item c1_strength, c1s
9501 @item c2_strength, c2s
9502 @item c3_strength, c3s
9503 Set noise strength for specific pixel component or all pixel components in case
9504 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
9506 @item all_flags, allf
9511 Set pixel component flags or set flags for all components if @var{all_flags}.
9512 Available values for component flags are:
9515 averaged temporal noise (smoother)
9517 mix random noise with a (semi)regular pattern
9519 temporal noise (noise pattern changes between frames)
9521 uniform noise (gaussian otherwise)
9525 @subsection Examples
9527 Add temporal and uniform noise to input video:
9529 noise=alls=20:allf=t+u
9534 Pass the video source unchanged to the output.
9537 Optical Character Recognition
9539 This filter uses Tesseract for optical character recognition.
9541 It accepts the following options:
9545 Set datapath to tesseract data. Default is to use whatever was
9546 set at installation.
9549 Set language, default is "eng".
9552 Set character whitelist.
9555 Set character blacklist.
9558 The filter exports recognized text as the frame metadata @code{lavfi.ocr.text}.
9562 Apply a video transform using libopencv.
9564 To enable this filter, install the libopencv library and headers and
9565 configure FFmpeg with @code{--enable-libopencv}.
9567 It accepts the following parameters:
9572 The name of the libopencv filter to apply.
9575 The parameters to pass to the libopencv filter. If not specified, the default
9580 Refer to the official libopencv documentation for more precise
9582 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
9584 Several libopencv filters are supported; see the following subsections.
9589 Dilate an image by using a specific structuring element.
9590 It corresponds to the libopencv function @code{cvDilate}.
9592 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
9594 @var{struct_el} represents a structuring element, and has the syntax:
9595 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
9597 @var{cols} and @var{rows} represent the number of columns and rows of
9598 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
9599 point, and @var{shape} the shape for the structuring element. @var{shape}
9600 must be "rect", "cross", "ellipse", or "custom".
9602 If the value for @var{shape} is "custom", it must be followed by a
9603 string of the form "=@var{filename}". The file with name
9604 @var{filename} is assumed to represent a binary image, with each
9605 printable character corresponding to a bright pixel. When a custom
9606 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
9607 or columns and rows of the read file are assumed instead.
9609 The default value for @var{struct_el} is "3x3+0x0/rect".
9611 @var{nb_iterations} specifies the number of times the transform is
9612 applied to the image, and defaults to 1.
9616 # Use the default values
9619 # Dilate using a structuring element with a 5x5 cross, iterating two times
9620 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
9622 # Read the shape from the file diamond.shape, iterating two times.
9623 # The file diamond.shape may contain a pattern of characters like this
9629 # The specified columns and rows are ignored
9630 # but the anchor point coordinates are not
9631 ocv=dilate:0x0+2x2/custom=diamond.shape|2
9636 Erode an image by using a specific structuring element.
9637 It corresponds to the libopencv function @code{cvErode}.
9639 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
9640 with the same syntax and semantics as the @ref{dilate} filter.
9644 Smooth the input video.
9646 The filter takes the following parameters:
9647 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
9649 @var{type} is the type of smooth filter to apply, and must be one of
9650 the following values: "blur", "blur_no_scale", "median", "gaussian",
9651 or "bilateral". The default value is "gaussian".
9653 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
9654 depend on the smooth type. @var{param1} and
9655 @var{param2} accept integer positive values or 0. @var{param3} and
9656 @var{param4} accept floating point values.
9658 The default value for @var{param1} is 3. The default value for the
9659 other parameters is 0.
9661 These parameters correspond to the parameters assigned to the
9662 libopencv function @code{cvSmooth}.
9667 Overlay one video on top of another.
9669 It takes two inputs and has one output. The first input is the "main"
9670 video on which the second input is overlaid.
9672 It accepts the following parameters:
9674 A description of the accepted options follows.
9679 Set the expression for the x and y coordinates of the overlaid video
9680 on the main video. Default value is "0" for both expressions. In case
9681 the expression is invalid, it is set to a huge value (meaning that the
9682 overlay will not be displayed within the output visible area).
9685 The action to take when EOF is encountered on the secondary input; it accepts
9686 one of the following values:
9690 Repeat the last frame (the default).
9694 Pass the main input through.
9698 Set when the expressions for @option{x}, and @option{y} are evaluated.
9700 It accepts the following values:
9703 only evaluate expressions once during the filter initialization or
9704 when a command is processed
9707 evaluate expressions for each incoming frame
9710 Default value is @samp{frame}.
9713 If set to 1, force the output to terminate when the shortest input
9714 terminates. Default value is 0.
9717 Set the format for the output video.
9719 It accepts the following values:
9734 Default value is @samp{yuv420}.
9736 @item rgb @emph{(deprecated)}
9737 If set to 1, force the filter to accept inputs in the RGB
9738 color space. Default value is 0. This option is deprecated, use
9739 @option{format} instead.
9742 If set to 1, force the filter to draw the last overlay frame over the
9743 main input until the end of the stream. A value of 0 disables this
9744 behavior. Default value is 1.
9747 The @option{x}, and @option{y} expressions can contain the following
9753 The main input width and height.
9757 The overlay input width and height.
9761 The computed values for @var{x} and @var{y}. They are evaluated for
9766 horizontal and vertical chroma subsample values of the output
9767 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
9771 the number of input frame, starting from 0
9774 the position in the file of the input frame, NAN if unknown
9777 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
9781 Note that the @var{n}, @var{pos}, @var{t} variables are available only
9782 when evaluation is done @emph{per frame}, and will evaluate to NAN
9783 when @option{eval} is set to @samp{init}.
9785 Be aware that frames are taken from each input video in timestamp
9786 order, hence, if their initial timestamps differ, it is a good idea
9787 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
9788 have them begin in the same zero timestamp, as the example for
9789 the @var{movie} filter does.
9791 You can chain together more overlays but you should test the
9792 efficiency of such approach.
9794 @subsection Commands
9796 This filter supports the following commands:
9800 Modify the x and y of the overlay input.
9801 The command accepts the same syntax of the corresponding option.
9803 If the specified expression is not valid, it is kept at its current
9807 @subsection Examples
9811 Draw the overlay at 10 pixels from the bottom right corner of the main
9814 overlay=main_w-overlay_w-10:main_h-overlay_h-10
9817 Using named options the example above becomes:
9819 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
9823 Insert a transparent PNG logo in the bottom left corner of the input,
9824 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
9826 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
9830 Insert 2 different transparent PNG logos (second logo on bottom
9831 right corner) using the @command{ffmpeg} tool:
9833 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
9837 Add a transparent color layer on top of the main video; @code{WxH}
9838 must specify the size of the main input to the overlay filter:
9840 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
9844 Play an original video and a filtered version (here with the deshake
9845 filter) side by side using the @command{ffplay} tool:
9847 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
9850 The above command is the same as:
9852 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
9856 Make a sliding overlay appearing from the left to the right top part of the
9857 screen starting since time 2:
9859 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
9863 Compose output by putting two input videos side to side:
9865 ffmpeg -i left.avi -i right.avi -filter_complex "
9866 nullsrc=size=200x100 [background];
9867 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
9868 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
9869 [background][left] overlay=shortest=1 [background+left];
9870 [background+left][right] overlay=shortest=1:x=100 [left+right]
9875 Mask 10-20 seconds of a video by applying the delogo filter to a section
9877 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
9878 -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]'
9883 Chain several overlays in cascade:
9885 nullsrc=s=200x200 [bg];
9886 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
9887 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
9888 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
9889 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
9890 [in3] null, [mid2] overlay=100:100 [out0]
9897 Apply Overcomplete Wavelet denoiser.
9899 The filter accepts the following options:
9905 Larger depth values will denoise lower frequency components more, but
9906 slow down filtering.
9908 Must be an int in the range 8-16, default is @code{8}.
9910 @item luma_strength, ls
9913 Must be a double value in the range 0-1000, default is @code{1.0}.
9915 @item chroma_strength, cs
9916 Set chroma strength.
9918 Must be a double value in the range 0-1000, default is @code{1.0}.
9924 Add paddings to the input image, and place the original input at the
9925 provided @var{x}, @var{y} coordinates.
9927 It accepts the following parameters:
9932 Specify an expression for the size of the output image with the
9933 paddings added. If the value for @var{width} or @var{height} is 0, the
9934 corresponding input size is used for the output.
9936 The @var{width} expression can reference the value set by the
9937 @var{height} expression, and vice versa.
9939 The default value of @var{width} and @var{height} is 0.
9943 Specify the offsets to place the input image at within the padded area,
9944 with respect to the top/left border of the output image.
9946 The @var{x} expression can reference the value set by the @var{y}
9947 expression, and vice versa.
9949 The default value of @var{x} and @var{y} is 0.
9952 Specify the color of the padded area. For the syntax of this option,
9953 check the "Color" section in the ffmpeg-utils manual.
9955 The default value of @var{color} is "black".
9958 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
9959 options are expressions containing the following constants:
9964 The input video width and height.
9968 These are the same as @var{in_w} and @var{in_h}.
9972 The output width and height (the size of the padded area), as
9973 specified by the @var{width} and @var{height} expressions.
9977 These are the same as @var{out_w} and @var{out_h}.
9981 The x and y offsets as specified by the @var{x} and @var{y}
9982 expressions, or NAN if not yet specified.
9985 same as @var{iw} / @var{ih}
9988 input sample aspect ratio
9991 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
9995 The horizontal and vertical chroma subsample values. For example for the
9996 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9999 @subsection Examples
10003 Add paddings with the color "violet" to the input video. The output video
10004 size is 640x480, and the top-left corner of the input video is placed at
10007 pad=640:480:0:40:violet
10010 The example above is equivalent to the following command:
10012 pad=width=640:height=480:x=0:y=40:color=violet
10016 Pad the input to get an output with dimensions increased by 3/2,
10017 and put the input video at the center of the padded area:
10019 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
10023 Pad the input to get a squared output with size equal to the maximum
10024 value between the input width and height, and put the input video at
10025 the center of the padded area:
10027 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
10031 Pad the input to get a final w/h ratio of 16:9:
10033 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
10037 In case of anamorphic video, in order to set the output display aspect
10038 correctly, it is necessary to use @var{sar} in the expression,
10039 according to the relation:
10041 (ih * X / ih) * sar = output_dar
10042 X = output_dar / sar
10045 Thus the previous example needs to be modified to:
10047 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
10051 Double the output size and put the input video in the bottom-right
10052 corner of the output padded area:
10054 pad="2*iw:2*ih:ow-iw:oh-ih"
10058 @anchor{palettegen}
10059 @section palettegen
10061 Generate one palette for a whole video stream.
10063 It accepts the following options:
10067 Set the maximum number of colors to quantize in the palette.
10068 Note: the palette will still contain 256 colors; the unused palette entries
10071 @item reserve_transparent
10072 Create a palette of 255 colors maximum and reserve the last one for
10073 transparency. Reserving the transparency color is useful for GIF optimization.
10074 If not set, the maximum of colors in the palette will be 256. You probably want
10075 to disable this option for a standalone image.
10079 Set statistics mode.
10081 It accepts the following values:
10084 Compute full frame histograms.
10086 Compute histograms only for the part that differs from previous frame. This
10087 might be relevant to give more importance to the moving part of your input if
10088 the background is static.
10091 Default value is @var{full}.
10094 The filter also exports the frame metadata @code{lavfi.color_quant_ratio}
10095 (@code{nb_color_in / nb_color_out}) which you can use to evaluate the degree of
10096 color quantization of the palette. This information is also visible at
10097 @var{info} logging level.
10099 @subsection Examples
10103 Generate a representative palette of a given video using @command{ffmpeg}:
10105 ffmpeg -i input.mkv -vf palettegen palette.png
10109 @section paletteuse
10111 Use a palette to downsample an input video stream.
10113 The filter takes two inputs: one video stream and a palette. The palette must
10114 be a 256 pixels image.
10116 It accepts the following options:
10120 Select dithering mode. Available algorithms are:
10123 Ordered 8x8 bayer dithering (deterministic)
10125 Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
10126 Note: this dithering is sometimes considered "wrong" and is included as a
10128 @item floyd_steinberg
10129 Floyd and Steingberg dithering (error diffusion)
10131 Frankie Sierra dithering v2 (error diffusion)
10133 Frankie Sierra dithering v2 "Lite" (error diffusion)
10136 Default is @var{sierra2_4a}.
10139 When @var{bayer} dithering is selected, this option defines the scale of the
10140 pattern (how much the crosshatch pattern is visible). A low value means more
10141 visible pattern for less banding, and higher value means less visible pattern
10142 at the cost of more banding.
10144 The option must be an integer value in the range [0,5]. Default is @var{2}.
10147 If set, define the zone to process
10151 Only the changing rectangle will be reprocessed. This is similar to GIF
10152 cropping/offsetting compression mechanism. This option can be useful for speed
10153 if only a part of the image is changing, and has use cases such as limiting the
10154 scope of the error diffusal @option{dither} to the rectangle that bounds the
10155 moving scene (it leads to more deterministic output if the scene doesn't change
10156 much, and as a result less moving noise and better GIF compression).
10159 Default is @var{none}.
10162 @subsection Examples
10166 Use a palette (generated for example with @ref{palettegen}) to encode a GIF
10167 using @command{ffmpeg}:
10169 ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
10173 @section perspective
10175 Correct perspective of video not recorded perpendicular to the screen.
10177 A description of the accepted parameters follows.
10188 Set coordinates expression for top left, top right, bottom left and bottom right corners.
10189 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
10190 If the @code{sense} option is set to @code{source}, then the specified points will be sent
10191 to the corners of the destination. If the @code{sense} option is set to @code{destination},
10192 then the corners of the source will be sent to the specified coordinates.
10194 The expressions can use the following variables:
10199 the width and height of video frame.
10203 Output frame count.
10206 @item interpolation
10207 Set interpolation for perspective correction.
10209 It accepts the following values:
10215 Default value is @samp{linear}.
10218 Set interpretation of coordinate options.
10220 It accepts the following values:
10224 Send point in the source specified by the given coordinates to
10225 the corners of the destination.
10227 @item 1, destination
10229 Send the corners of the source to the point in the destination specified
10230 by the given coordinates.
10232 Default value is @samp{source}.
10236 Set when the expressions for coordinates @option{x0,y0,...x3,y3} are evaluated.
10238 It accepts the following values:
10241 only evaluate expressions once during the filter initialization or
10242 when a command is processed
10245 evaluate expressions for each incoming frame
10248 Default value is @samp{init}.
10253 Delay interlaced video by one field time so that the field order changes.
10255 The intended use is to fix PAL movies that have been captured with the
10256 opposite field order to the film-to-video transfer.
10258 A description of the accepted parameters follows.
10264 It accepts the following values:
10267 Capture field order top-first, transfer bottom-first.
10268 Filter will delay the bottom field.
10271 Capture field order bottom-first, transfer top-first.
10272 Filter will delay the top field.
10275 Capture and transfer with the same field order. This mode only exists
10276 for the documentation of the other options to refer to, but if you
10277 actually select it, the filter will faithfully do nothing.
10280 Capture field order determined automatically by field flags, transfer
10282 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
10283 basis using field flags. If no field information is available,
10284 then this works just like @samp{u}.
10287 Capture unknown or varying, transfer opposite.
10288 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
10289 analyzing the images and selecting the alternative that produces best
10290 match between the fields.
10293 Capture top-first, transfer unknown or varying.
10294 Filter selects among @samp{t} and @samp{p} using image analysis.
10297 Capture bottom-first, transfer unknown or varying.
10298 Filter selects among @samp{b} and @samp{p} using image analysis.
10301 Capture determined by field flags, transfer unknown or varying.
10302 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
10303 image analysis. If no field information is available, then this works just
10304 like @samp{U}. This is the default mode.
10307 Both capture and transfer unknown or varying.
10308 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
10312 @section pixdesctest
10314 Pixel format descriptor test filter, mainly useful for internal
10315 testing. The output video should be equal to the input video.
10319 format=monow, pixdesctest
10322 can be used to test the monowhite pixel format descriptor definition.
10326 Enable the specified chain of postprocessing subfilters using libpostproc. This
10327 library should be automatically selected with a GPL build (@code{--enable-gpl}).
10328 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
10329 Each subfilter and some options have a short and a long name that can be used
10330 interchangeably, i.e. dr/dering are the same.
10332 The filters accept the following options:
10336 Set postprocessing subfilters string.
10339 All subfilters share common options to determine their scope:
10343 Honor the quality commands for this subfilter.
10346 Do chrominance filtering, too (default).
10349 Do luminance filtering only (no chrominance).
10352 Do chrominance filtering only (no luminance).
10355 These options can be appended after the subfilter name, separated by a '|'.
10357 Available subfilters are:
10360 @item hb/hdeblock[|difference[|flatness]]
10361 Horizontal deblocking filter
10364 Difference factor where higher values mean more deblocking (default: @code{32}).
10366 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10369 @item vb/vdeblock[|difference[|flatness]]
10370 Vertical deblocking filter
10373 Difference factor where higher values mean more deblocking (default: @code{32}).
10375 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10378 @item ha/hadeblock[|difference[|flatness]]
10379 Accurate horizontal deblocking filter
10382 Difference factor where higher values mean more deblocking (default: @code{32}).
10384 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10387 @item va/vadeblock[|difference[|flatness]]
10388 Accurate vertical deblocking filter
10391 Difference factor where higher values mean more deblocking (default: @code{32}).
10393 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10397 The horizontal and vertical deblocking filters share the difference and
10398 flatness values so you cannot set different horizontal and vertical
10402 @item h1/x1hdeblock
10403 Experimental horizontal deblocking filter
10405 @item v1/x1vdeblock
10406 Experimental vertical deblocking filter
10411 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
10414 larger -> stronger filtering
10416 larger -> stronger filtering
10418 larger -> stronger filtering
10421 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
10424 Stretch luminance to @code{0-255}.
10427 @item lb/linblenddeint
10428 Linear blend deinterlacing filter that deinterlaces the given block by
10429 filtering all lines with a @code{(1 2 1)} filter.
10431 @item li/linipoldeint
10432 Linear interpolating deinterlacing filter that deinterlaces the given block by
10433 linearly interpolating every second line.
10435 @item ci/cubicipoldeint
10436 Cubic interpolating deinterlacing filter deinterlaces the given block by
10437 cubically interpolating every second line.
10439 @item md/mediandeint
10440 Median deinterlacing filter that deinterlaces the given block by applying a
10441 median filter to every second line.
10443 @item fd/ffmpegdeint
10444 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
10445 second line with a @code{(-1 4 2 4 -1)} filter.
10448 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
10449 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
10451 @item fq/forceQuant[|quantizer]
10452 Overrides the quantizer table from the input with the constant quantizer you
10460 Default pp filter combination (@code{hb|a,vb|a,dr|a})
10463 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
10466 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
10469 @subsection Examples
10473 Apply horizontal and vertical deblocking, deringing and automatic
10474 brightness/contrast:
10480 Apply default filters without brightness/contrast correction:
10486 Apply default filters and temporal denoiser:
10488 pp=default/tmpnoise|1|2|3
10492 Apply deblocking on luminance only, and switch vertical deblocking on or off
10493 automatically depending on available CPU time:
10500 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
10501 similar to spp = 6 with 7 point DCT, where only the center sample is
10504 The filter accepts the following options:
10508 Force a constant quantization parameter. It accepts an integer in range
10509 0 to 63. If not set, the filter will use the QP from the video stream
10513 Set thresholding mode. Available modes are:
10517 Set hard thresholding.
10519 Set soft thresholding (better de-ringing effect, but likely blurrier).
10521 Set medium thresholding (good results, default).
10527 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
10528 Ratio) between two input videos.
10530 This filter takes in input two input videos, the first input is
10531 considered the "main" source and is passed unchanged to the
10532 output. The second input is used as a "reference" video for computing
10535 Both video inputs must have the same resolution and pixel format for
10536 this filter to work correctly. Also it assumes that both inputs
10537 have the same number of frames, which are compared one by one.
10539 The obtained average PSNR is printed through the logging system.
10541 The filter stores the accumulated MSE (mean squared error) of each
10542 frame, and at the end of the processing it is averaged across all frames
10543 equally, and the following formula is applied to obtain the PSNR:
10546 PSNR = 10*log10(MAX^2/MSE)
10549 Where MAX is the average of the maximum values of each component of the
10552 The description of the accepted parameters follows.
10555 @item stats_file, f
10556 If specified the filter will use the named file to save the PSNR of
10557 each individual frame. When filename equals "-" the data is sent to
10561 The file printed if @var{stats_file} is selected, contains a sequence of
10562 key/value pairs of the form @var{key}:@var{value} for each compared
10565 A description of each shown parameter follows:
10569 sequential number of the input frame, starting from 1
10572 Mean Square Error pixel-by-pixel average difference of the compared
10573 frames, averaged over all the image components.
10575 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
10576 Mean Square Error pixel-by-pixel average difference of the compared
10577 frames for the component specified by the suffix.
10579 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
10580 Peak Signal to Noise ratio of the compared frames for the component
10581 specified by the suffix.
10586 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
10587 [main][ref] psnr="stats_file=stats.log" [out]
10590 On this example the input file being processed is compared with the
10591 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
10592 is stored in @file{stats.log}.
10597 Pulldown reversal (inverse telecine) filter, capable of handling mixed
10598 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
10601 The pullup filter is designed to take advantage of future context in making
10602 its decisions. This filter is stateless in the sense that it does not lock
10603 onto a pattern to follow, but it instead looks forward to the following
10604 fields in order to identify matches and rebuild progressive frames.
10606 To produce content with an even framerate, insert the fps filter after
10607 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
10608 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
10610 The filter accepts the following options:
10617 These options set the amount of "junk" to ignore at the left, right, top, and
10618 bottom of the image, respectively. Left and right are in units of 8 pixels,
10619 while top and bottom are in units of 2 lines.
10620 The default is 8 pixels on each side.
10623 Set the strict breaks. Setting this option to 1 will reduce the chances of
10624 filter generating an occasional mismatched frame, but it may also cause an
10625 excessive number of frames to be dropped during high motion sequences.
10626 Conversely, setting it to -1 will make filter match fields more easily.
10627 This may help processing of video where there is slight blurring between
10628 the fields, but may also cause there to be interlaced frames in the output.
10629 Default value is @code{0}.
10632 Set the metric plane to use. It accepts the following values:
10638 Use chroma blue plane.
10641 Use chroma red plane.
10644 This option may be set to use chroma plane instead of the default luma plane
10645 for doing filter's computations. This may improve accuracy on very clean
10646 source material, but more likely will decrease accuracy, especially if there
10647 is chroma noise (rainbow effect) or any grayscale video.
10648 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
10649 load and make pullup usable in realtime on slow machines.
10652 For best results (without duplicated frames in the output file) it is
10653 necessary to change the output frame rate. For example, to inverse
10654 telecine NTSC input:
10656 ffmpeg -i input -vf pullup -r 24000/1001 ...
10661 Change video quantization parameters (QP).
10663 The filter accepts the following option:
10667 Set expression for quantization parameter.
10670 The expression is evaluated through the eval API and can contain, among others,
10671 the following constants:
10675 1 if index is not 129, 0 otherwise.
10678 Sequentional index starting from -129 to 128.
10681 @subsection Examples
10685 Some equation like:
10693 Flush video frames from internal cache of frames into a random order.
10694 No frame is discarded.
10695 Inspired by @ref{frei0r} nervous filter.
10699 Set size in number of frames of internal cache, in range from @code{2} to
10700 @code{512}. Default is @code{30}.
10703 Set seed for random number generator, must be an integer included between
10704 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
10705 less than @code{0}, the filter will try to use a good random seed on a
10711 Read vertical interval timecode (VITC) information from the top lines of a
10714 The filter adds frame metadata key @code{lavfi.readvitc.tc_str} with the
10715 timecode value, if a valid timecode has been detected. Further metadata key
10716 @code{lavfi.readvitc.found} is set to 0/1 depending on whether
10717 timecode data has been found or not.
10719 This filter accepts the following options:
10723 Set the maximum number of lines to scan for VITC data. If the value is set to
10724 @code{-1} the full video frame is scanned. Default is @code{45}.
10727 Set the luma threshold for black. Accepts float numbers in the range [0.0,1.0],
10728 default value is @code{0.2}. The value must be equal or less than @code{thr_w}.
10731 Set the luma threshold for white. Accepts float numbers in the range [0.0,1.0],
10732 default value is @code{0.6}. The value must be equal or greater than @code{thr_b}.
10735 @subsection Examples
10739 Detect and draw VITC data onto the video frame; if no valid VITC is detected,
10740 draw @code{--:--:--:--} as a placeholder:
10742 ffmpeg -i input.avi -filter:v 'readvitc,drawtext=fontfile=FreeMono.ttf:text=%@{metadata\\:lavfi.readvitc.tc_str\\:--\\\\\\:--\\\\\\:--\\\\\\:--@}:x=(w-tw)/2:y=400-ascent'
10748 Remap pixels using 2nd: Xmap and 3rd: Ymap input video stream.
10750 Destination pixel at position (X, Y) will be picked from source (x, y) position
10751 where x = Xmap(X, Y) and y = Ymap(X, Y). If mapping values are out of range, zero
10752 value for pixel will be used for destination pixel.
10754 Xmap and Ymap input video streams must be of same dimensions. Output video stream
10755 will have Xmap/Ymap video stream dimensions.
10756 Xmap and Ymap input video streams are 16bit depth, single channel.
10758 @section removegrain
10760 The removegrain filter is a spatial denoiser for progressive video.
10764 Set mode for the first plane.
10767 Set mode for the second plane.
10770 Set mode for the third plane.
10773 Set mode for the fourth plane.
10776 Range of mode is from 0 to 24. Description of each mode follows:
10780 Leave input plane unchanged. Default.
10783 Clips the pixel with the minimum and maximum of the 8 neighbour pixels.
10786 Clips the pixel with the second minimum and maximum of the 8 neighbour pixels.
10789 Clips the pixel with the third minimum and maximum of the 8 neighbour pixels.
10792 Clips the pixel with the fourth minimum and maximum of the 8 neighbour pixels.
10793 This is equivalent to a median filter.
10796 Line-sensitive clipping giving the minimal change.
10799 Line-sensitive clipping, intermediate.
10802 Line-sensitive clipping, intermediate.
10805 Line-sensitive clipping, intermediate.
10808 Line-sensitive clipping on a line where the neighbours pixels are the closest.
10811 Replaces the target pixel with the closest neighbour.
10814 [1 2 1] horizontal and vertical kernel blur.
10820 Bob mode, interpolates top field from the line where the neighbours
10821 pixels are the closest.
10824 Bob mode, interpolates bottom field from the line where the neighbours
10825 pixels are the closest.
10828 Bob mode, interpolates top field. Same as 13 but with a more complicated
10829 interpolation formula.
10832 Bob mode, interpolates bottom field. Same as 14 but with a more complicated
10833 interpolation formula.
10836 Clips the pixel with the minimum and maximum of respectively the maximum and
10837 minimum of each pair of opposite neighbour pixels.
10840 Line-sensitive clipping using opposite neighbours whose greatest distance from
10841 the current pixel is minimal.
10844 Replaces the pixel with the average of its 8 neighbours.
10847 Averages the 9 pixels ([1 1 1] horizontal and vertical blur).
10850 Clips pixels using the averages of opposite neighbour.
10853 Same as mode 21 but simpler and faster.
10856 Small edge and halo removal, but reputed useless.
10862 @section removelogo
10864 Suppress a TV station logo, using an image file to determine which
10865 pixels comprise the logo. It works by filling in the pixels that
10866 comprise the logo with neighboring pixels.
10868 The filter accepts the following options:
10872 Set the filter bitmap file, which can be any image format supported by
10873 libavformat. The width and height of the image file must match those of the
10874 video stream being processed.
10877 Pixels in the provided bitmap image with a value of zero are not
10878 considered part of the logo, non-zero pixels are considered part of
10879 the logo. If you use white (255) for the logo and black (0) for the
10880 rest, you will be safe. For making the filter bitmap, it is
10881 recommended to take a screen capture of a black frame with the logo
10882 visible, and then using a threshold filter followed by the erode
10883 filter once or twice.
10885 If needed, little splotches can be fixed manually. Remember that if
10886 logo pixels are not covered, the filter quality will be much
10887 reduced. Marking too many pixels as part of the logo does not hurt as
10888 much, but it will increase the amount of blurring needed to cover over
10889 the image and will destroy more information than necessary, and extra
10890 pixels will slow things down on a large logo.
10892 @section repeatfields
10894 This filter uses the repeat_field flag from the Video ES headers and hard repeats
10895 fields based on its value.
10897 @section reverse, areverse
10901 Warning: This filter requires memory to buffer the entire clip, so trimming
10904 @subsection Examples
10908 Take the first 5 seconds of a clip, and reverse it.
10916 Rotate video by an arbitrary angle expressed in radians.
10918 The filter accepts the following options:
10920 A description of the optional parameters follows.
10923 Set an expression for the angle by which to rotate the input video
10924 clockwise, expressed as a number of radians. A negative value will
10925 result in a counter-clockwise rotation. By default it is set to "0".
10927 This expression is evaluated for each frame.
10930 Set the output width expression, default value is "iw".
10931 This expression is evaluated just once during configuration.
10934 Set the output height expression, default value is "ih".
10935 This expression is evaluated just once during configuration.
10938 Enable bilinear interpolation if set to 1, a value of 0 disables
10939 it. Default value is 1.
10942 Set the color used to fill the output area not covered by the rotated
10943 image. For the general syntax of this option, check the "Color" section in the
10944 ffmpeg-utils manual. If the special value "none" is selected then no
10945 background is printed (useful for example if the background is never shown).
10947 Default value is "black".
10950 The expressions for the angle and the output size can contain the
10951 following constants and functions:
10955 sequential number of the input frame, starting from 0. It is always NAN
10956 before the first frame is filtered.
10959 time in seconds of the input frame, it is set to 0 when the filter is
10960 configured. It is always NAN before the first frame is filtered.
10964 horizontal and vertical chroma subsample values. For example for the
10965 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
10969 the input video width and height
10973 the output width and height, that is the size of the padded area as
10974 specified by the @var{width} and @var{height} expressions
10978 the minimal width/height required for completely containing the input
10979 video rotated by @var{a} radians.
10981 These are only available when computing the @option{out_w} and
10982 @option{out_h} expressions.
10985 @subsection Examples
10989 Rotate the input by PI/6 radians clockwise:
10995 Rotate the input by PI/6 radians counter-clockwise:
11001 Rotate the input by 45 degrees clockwise:
11007 Apply a constant rotation with period T, starting from an angle of PI/3:
11009 rotate=PI/3+2*PI*t/T
11013 Make the input video rotation oscillating with a period of T
11014 seconds and an amplitude of A radians:
11016 rotate=A*sin(2*PI/T*t)
11020 Rotate the video, output size is chosen so that the whole rotating
11021 input video is always completely contained in the output:
11023 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
11027 Rotate the video, reduce the output size so that no background is ever
11030 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
11034 @subsection Commands
11036 The filter supports the following commands:
11040 Set the angle expression.
11041 The command accepts the same syntax of the corresponding option.
11043 If the specified expression is not valid, it is kept at its current
11049 Apply Shape Adaptive Blur.
11051 The filter accepts the following options:
11054 @item luma_radius, lr
11055 Set luma blur filter strength, must be a value in range 0.1-4.0, default
11056 value is 1.0. A greater value will result in a more blurred image, and
11057 in slower processing.
11059 @item luma_pre_filter_radius, lpfr
11060 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
11063 @item luma_strength, ls
11064 Set luma maximum difference between pixels to still be considered, must
11065 be a value in the 0.1-100.0 range, default value is 1.0.
11067 @item chroma_radius, cr
11068 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
11069 greater value will result in a more blurred image, and in slower
11072 @item chroma_pre_filter_radius, cpfr
11073 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
11075 @item chroma_strength, cs
11076 Set chroma maximum difference between pixels to still be considered,
11077 must be a value in the 0.1-100.0 range.
11080 Each chroma option value, if not explicitly specified, is set to the
11081 corresponding luma option value.
11086 Scale (resize) the input video, using the libswscale library.
11088 The scale filter forces the output display aspect ratio to be the same
11089 of the input, by changing the output sample aspect ratio.
11091 If the input image format is different from the format requested by
11092 the next filter, the scale filter will convert the input to the
11095 @subsection Options
11096 The filter accepts the following options, or any of the options
11097 supported by the libswscale scaler.
11099 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
11100 the complete list of scaler options.
11105 Set the output video dimension expression. Default value is the input
11108 If the value is 0, the input width is used for the output.
11110 If one of the values is -1, the scale filter will use a value that
11111 maintains the aspect ratio of the input image, calculated from the
11112 other specified dimension. If both of them are -1, the input size is
11115 If one of the values is -n with n > 1, the scale filter will also use a value
11116 that maintains the aspect ratio of the input image, calculated from the other
11117 specified dimension. After that it will, however, make sure that the calculated
11118 dimension is divisible by n and adjust the value if necessary.
11120 See below for the list of accepted constants for use in the dimension
11124 Specify when to evaluate @var{width} and @var{height} expression. It accepts the following values:
11128 Only evaluate expressions once during the filter initialization or when a command is processed.
11131 Evaluate expressions for each incoming frame.
11135 Default value is @samp{init}.
11139 Set the interlacing mode. It accepts the following values:
11143 Force interlaced aware scaling.
11146 Do not apply interlaced scaling.
11149 Select interlaced aware scaling depending on whether the source frames
11150 are flagged as interlaced or not.
11153 Default value is @samp{0}.
11156 Set libswscale scaling flags. See
11157 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
11158 complete list of values. If not explicitly specified the filter applies
11162 @item param0, param1
11163 Set libswscale input parameters for scaling algorithms that need them. See
11164 @ref{sws_params,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
11165 complete documentation. If not explicitly specified the filter applies
11171 Set the video size. For the syntax of this option, check the
11172 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11174 @item in_color_matrix
11175 @item out_color_matrix
11176 Set in/output YCbCr color space type.
11178 This allows the autodetected value to be overridden as well as allows forcing
11179 a specific value used for the output and encoder.
11181 If not specified, the color space type depends on the pixel format.
11187 Choose automatically.
11190 Format conforming to International Telecommunication Union (ITU)
11191 Recommendation BT.709.
11194 Set color space conforming to the United States Federal Communications
11195 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
11198 Set color space conforming to:
11202 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
11205 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
11208 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
11213 Set color space conforming to SMPTE ST 240:1999.
11218 Set in/output YCbCr sample range.
11220 This allows the autodetected value to be overridden as well as allows forcing
11221 a specific value used for the output and encoder. If not specified, the
11222 range depends on the pixel format. Possible values:
11226 Choose automatically.
11229 Set full range (0-255 in case of 8-bit luma).
11232 Set "MPEG" range (16-235 in case of 8-bit luma).
11235 @item force_original_aspect_ratio
11236 Enable decreasing or increasing output video width or height if necessary to
11237 keep the original aspect ratio. Possible values:
11241 Scale the video as specified and disable this feature.
11244 The output video dimensions will automatically be decreased if needed.
11247 The output video dimensions will automatically be increased if needed.
11251 One useful instance of this option is that when you know a specific device's
11252 maximum allowed resolution, you can use this to limit the output video to
11253 that, while retaining the aspect ratio. For example, device A allows
11254 1280x720 playback, and your video is 1920x800. Using this option (set it to
11255 decrease) and specifying 1280x720 to the command line makes the output
11258 Please note that this is a different thing than specifying -1 for @option{w}
11259 or @option{h}, you still need to specify the output resolution for this option
11264 The values of the @option{w} and @option{h} options are expressions
11265 containing the following constants:
11270 The input width and height
11274 These are the same as @var{in_w} and @var{in_h}.
11278 The output (scaled) width and height
11282 These are the same as @var{out_w} and @var{out_h}
11285 The same as @var{iw} / @var{ih}
11288 input sample aspect ratio
11291 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
11295 horizontal and vertical input chroma subsample values. For example for the
11296 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11300 horizontal and vertical output chroma subsample values. For example for the
11301 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11304 @subsection Examples
11308 Scale the input video to a size of 200x100
11313 This is equivalent to:
11324 Specify a size abbreviation for the output size:
11329 which can also be written as:
11335 Scale the input to 2x:
11337 scale=w=2*iw:h=2*ih
11341 The above is the same as:
11343 scale=2*in_w:2*in_h
11347 Scale the input to 2x with forced interlaced scaling:
11349 scale=2*iw:2*ih:interl=1
11353 Scale the input to half size:
11355 scale=w=iw/2:h=ih/2
11359 Increase the width, and set the height to the same size:
11365 Seek Greek harmony:
11372 Increase the height, and set the width to 3/2 of the height:
11374 scale=w=3/2*oh:h=3/5*ih
11378 Increase the size, making the size a multiple of the chroma
11381 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
11385 Increase the width to a maximum of 500 pixels,
11386 keeping the same aspect ratio as the input:
11388 scale=w='min(500\, iw*3/2):h=-1'
11392 @subsection Commands
11394 This filter supports the following commands:
11398 Set the output video dimension expression.
11399 The command accepts the same syntax of the corresponding option.
11401 If the specified expression is not valid, it is kept at its current
11407 Scale (resize) the input video, based on a reference video.
11409 See the scale filter for available options, scale2ref supports the same but
11410 uses the reference video instead of the main input as basis.
11412 @subsection Examples
11416 Scale a subtitle stream to match the main video in size before overlaying
11418 'scale2ref[b][a];[a][b]overlay'
11422 @anchor{selectivecolor}
11423 @section selectivecolor
11425 Adjust cyan, magenta, yellow and black (CMYK) to certain ranges of colors (such
11426 as "reds", "yellows", "greens", "cyans", ...). The adjustment range is defined
11427 by the "purity" of the color (that is, how saturated it already is).
11429 This filter is similar to the Adobe Photoshop Selective Color tool.
11431 The filter accepts the following options:
11434 @item correction_method
11435 Select color correction method.
11437 Available values are:
11440 Specified adjustments are applied "as-is" (added/subtracted to original pixel
11443 Specified adjustments are relative to the original component value.
11445 Default is @code{absolute}.
11447 Adjustments for red pixels (pixels where the red component is the maximum)
11449 Adjustments for yellow pixels (pixels where the blue component is the minimum)
11451 Adjustments for green pixels (pixels where the green component is the maximum)
11453 Adjustments for cyan pixels (pixels where the red component is the minimum)
11455 Adjustments for blue pixels (pixels where the blue component is the maximum)
11457 Adjustments for magenta pixels (pixels where the green component is the minimum)
11459 Adjustments for white pixels (pixels where all components are greater than 128)
11461 Adjustments for all pixels except pure black and pure white
11463 Adjustments for black pixels (pixels where all components are lesser than 128)
11465 Specify a Photoshop selective color file (@code{.asv}) to import the settings from.
11468 All the adjustment settings (@option{reds}, @option{yellows}, ...) accept up to
11469 4 space separated floating point adjustment values in the [-1,1] range,
11470 respectively to adjust the amount of cyan, magenta, yellow and black for the
11471 pixels of its range.
11473 @subsection Examples
11477 Increase cyan by 50% and reduce yellow by 33% in every green areas, and
11478 increase magenta by 27% in blue areas:
11480 selectivecolor=greens=.5 0 -.33 0:blues=0 .27
11484 Use a Photoshop selective color preset:
11486 selectivecolor=psfile=MySelectiveColorPresets/Misty.asv
11490 @section separatefields
11492 The @code{separatefields} takes a frame-based video input and splits
11493 each frame into its components fields, producing a new half height clip
11494 with twice the frame rate and twice the frame count.
11496 This filter use field-dominance information in frame to decide which
11497 of each pair of fields to place first in the output.
11498 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
11500 @section setdar, setsar
11502 The @code{setdar} filter sets the Display Aspect Ratio for the filter
11505 This is done by changing the specified Sample (aka Pixel) Aspect
11506 Ratio, according to the following equation:
11508 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
11511 Keep in mind that the @code{setdar} filter does not modify the pixel
11512 dimensions of the video frame. Also, the display aspect ratio set by
11513 this filter may be changed by later filters in the filterchain,
11514 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
11517 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
11518 the filter output video.
11520 Note that as a consequence of the application of this filter, the
11521 output display aspect ratio will change according to the equation
11524 Keep in mind that the sample aspect ratio set by the @code{setsar}
11525 filter may be changed by later filters in the filterchain, e.g. if
11526 another "setsar" or a "setdar" filter is applied.
11528 It accepts the following parameters:
11531 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
11532 Set the aspect ratio used by the filter.
11534 The parameter can be a floating point number string, an expression, or
11535 a string of the form @var{num}:@var{den}, where @var{num} and
11536 @var{den} are the numerator and denominator of the aspect ratio. If
11537 the parameter is not specified, it is assumed the value "0".
11538 In case the form "@var{num}:@var{den}" is used, the @code{:} character
11542 Set the maximum integer value to use for expressing numerator and
11543 denominator when reducing the expressed aspect ratio to a rational.
11544 Default value is @code{100}.
11548 The parameter @var{sar} is an expression containing
11549 the following constants:
11553 These are approximated values for the mathematical constants e
11554 (Euler's number), pi (Greek pi), and phi (the golden ratio).
11557 The input width and height.
11560 These are the same as @var{w} / @var{h}.
11563 The input sample aspect ratio.
11566 The input display aspect ratio. It is the same as
11567 (@var{w} / @var{h}) * @var{sar}.
11570 Horizontal and vertical chroma subsample values. For example, for the
11571 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11574 @subsection Examples
11579 To change the display aspect ratio to 16:9, specify one of the following:
11587 To change the sample aspect ratio to 10:11, specify:
11593 To set a display aspect ratio of 16:9, and specify a maximum integer value of
11594 1000 in the aspect ratio reduction, use the command:
11596 setdar=ratio=16/9:max=1000
11604 Force field for the output video frame.
11606 The @code{setfield} filter marks the interlace type field for the
11607 output frames. It does not change the input frame, but only sets the
11608 corresponding property, which affects how the frame is treated by
11609 following filters (e.g. @code{fieldorder} or @code{yadif}).
11611 The filter accepts the following options:
11616 Available values are:
11620 Keep the same field property.
11623 Mark the frame as bottom-field-first.
11626 Mark the frame as top-field-first.
11629 Mark the frame as progressive.
11635 Show a line containing various information for each input video frame.
11636 The input video is not modified.
11638 The shown line contains a sequence of key/value pairs of the form
11639 @var{key}:@var{value}.
11641 The following values are shown in the output:
11645 The (sequential) number of the input frame, starting from 0.
11648 The Presentation TimeStamp of the input frame, expressed as a number of
11649 time base units. The time base unit depends on the filter input pad.
11652 The Presentation TimeStamp of the input frame, expressed as a number of
11656 The position of the frame in the input stream, or -1 if this information is
11657 unavailable and/or meaningless (for example in case of synthetic video).
11660 The pixel format name.
11663 The sample aspect ratio of the input frame, expressed in the form
11664 @var{num}/@var{den}.
11667 The size of the input frame. For the syntax of this option, check the
11668 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11671 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
11672 for bottom field first).
11675 This is 1 if the frame is a key frame, 0 otherwise.
11678 The picture type of the input frame ("I" for an I-frame, "P" for a
11679 P-frame, "B" for a B-frame, or "?" for an unknown type).
11680 Also refer to the documentation of the @code{AVPictureType} enum and of
11681 the @code{av_get_picture_type_char} function defined in
11682 @file{libavutil/avutil.h}.
11685 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
11687 @item plane_checksum
11688 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
11689 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
11692 @section showpalette
11694 Displays the 256 colors palette of each frame. This filter is only relevant for
11695 @var{pal8} pixel format frames.
11697 It accepts the following option:
11701 Set the size of the box used to represent one palette color entry. Default is
11702 @code{30} (for a @code{30x30} pixel box).
11705 @section shuffleframes
11707 Reorder and/or duplicate video frames.
11709 It accepts the following parameters:
11713 Set the destination indexes of input frames.
11714 This is space or '|' separated list of indexes that maps input frames to output
11715 frames. Number of indexes also sets maximal value that each index may have.
11718 The first frame has the index 0. The default is to keep the input unchanged.
11720 Swap second and third frame of every three frames of the input:
11722 ffmpeg -i INPUT -vf "shuffleframes=0 2 1" OUTPUT
11725 @section shuffleplanes
11727 Reorder and/or duplicate video planes.
11729 It accepts the following parameters:
11734 The index of the input plane to be used as the first output plane.
11737 The index of the input plane to be used as the second output plane.
11740 The index of the input plane to be used as the third output plane.
11743 The index of the input plane to be used as the fourth output plane.
11747 The first plane has the index 0. The default is to keep the input unchanged.
11749 Swap the second and third planes of the input:
11751 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
11754 @anchor{signalstats}
11755 @section signalstats
11756 Evaluate various visual metrics that assist in determining issues associated
11757 with the digitization of analog video media.
11759 By default the filter will log these metadata values:
11763 Display the minimal Y value contained within the input frame. Expressed in
11767 Display the Y value at the 10% percentile within the input frame. Expressed in
11771 Display the average Y value within the input frame. Expressed in range of
11775 Display the Y value at the 90% percentile within the input frame. Expressed in
11779 Display the maximum Y value contained within the input frame. Expressed in
11783 Display the minimal U value contained within the input frame. Expressed in
11787 Display the U value at the 10% percentile within the input frame. Expressed in
11791 Display the average U value within the input frame. Expressed in range of
11795 Display the U value at the 90% percentile within the input frame. Expressed in
11799 Display the maximum U value contained within the input frame. Expressed in
11803 Display the minimal V value contained within the input frame. Expressed in
11807 Display the V value at the 10% percentile within the input frame. Expressed in
11811 Display the average V value within the input frame. Expressed in range of
11815 Display the V value at the 90% percentile within the input frame. Expressed in
11819 Display the maximum V value contained within the input frame. Expressed in
11823 Display the minimal saturation value contained within the input frame.
11824 Expressed in range of [0-~181.02].
11827 Display the saturation value at the 10% percentile within the input frame.
11828 Expressed in range of [0-~181.02].
11831 Display the average saturation value within the input frame. Expressed in range
11835 Display the saturation value at the 90% percentile within the input frame.
11836 Expressed in range of [0-~181.02].
11839 Display the maximum saturation value contained within the input frame.
11840 Expressed in range of [0-~181.02].
11843 Display the median value for hue within the input frame. Expressed in range of
11847 Display the average value for hue within the input frame. Expressed in range of
11851 Display the average of sample value difference between all values of the Y
11852 plane in the current frame and corresponding values of the previous input frame.
11853 Expressed in range of [0-255].
11856 Display the average of sample value difference between all values of the U
11857 plane in the current frame and corresponding values of the previous input frame.
11858 Expressed in range of [0-255].
11861 Display the average of sample value difference between all values of the V
11862 plane in the current frame and corresponding values of the previous input frame.
11863 Expressed in range of [0-255].
11866 The filter accepts the following options:
11872 @option{stat} specify an additional form of image analysis.
11873 @option{out} output video with the specified type of pixel highlighted.
11875 Both options accept the following values:
11879 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
11880 unlike the neighboring pixels of the same field. Examples of temporal outliers
11881 include the results of video dropouts, head clogs, or tape tracking issues.
11884 Identify @var{vertical line repetition}. Vertical line repetition includes
11885 similar rows of pixels within a frame. In born-digital video vertical line
11886 repetition is common, but this pattern is uncommon in video digitized from an
11887 analog source. When it occurs in video that results from the digitization of an
11888 analog source it can indicate concealment from a dropout compensator.
11891 Identify pixels that fall outside of legal broadcast range.
11895 Set the highlight color for the @option{out} option. The default color is
11899 @subsection Examples
11903 Output data of various video metrics:
11905 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
11909 Output specific data about the minimum and maximum values of the Y plane per frame:
11911 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
11915 Playback video while highlighting pixels that are outside of broadcast range in red.
11917 ffplay example.mov -vf signalstats="out=brng:color=red"
11921 Playback video with signalstats metadata drawn over the frame.
11923 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
11926 The contents of signalstat_drawtext.txt used in the command are:
11929 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
11930 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
11931 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
11932 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
11940 Blur the input video without impacting the outlines.
11942 It accepts the following options:
11945 @item luma_radius, lr
11946 Set the luma radius. The option value must be a float number in
11947 the range [0.1,5.0] that specifies the variance of the gaussian filter
11948 used to blur the image (slower if larger). Default value is 1.0.
11950 @item luma_strength, ls
11951 Set the luma strength. The option value must be a float number
11952 in the range [-1.0,1.0] that configures the blurring. A value included
11953 in [0.0,1.0] will blur the image whereas a value included in
11954 [-1.0,0.0] will sharpen the image. Default value is 1.0.
11956 @item luma_threshold, lt
11957 Set the luma threshold used as a coefficient to determine
11958 whether a pixel should be blurred or not. The option value must be an
11959 integer in the range [-30,30]. A value of 0 will filter all the image,
11960 a value included in [0,30] will filter flat areas and a value included
11961 in [-30,0] will filter edges. Default value is 0.
11963 @item chroma_radius, cr
11964 Set the chroma radius. The option value must be a float number in
11965 the range [0.1,5.0] that specifies the variance of the gaussian filter
11966 used to blur the image (slower if larger). Default value is 1.0.
11968 @item chroma_strength, cs
11969 Set the chroma strength. The option value must be a float number
11970 in the range [-1.0,1.0] that configures the blurring. A value included
11971 in [0.0,1.0] will blur the image whereas a value included in
11972 [-1.0,0.0] will sharpen the image. Default value is 1.0.
11974 @item chroma_threshold, ct
11975 Set the chroma threshold used as a coefficient to determine
11976 whether a pixel should be blurred or not. The option value must be an
11977 integer in the range [-30,30]. A value of 0 will filter all the image,
11978 a value included in [0,30] will filter flat areas and a value included
11979 in [-30,0] will filter edges. Default value is 0.
11982 If a chroma option is not explicitly set, the corresponding luma value
11987 Obtain the SSIM (Structural SImilarity Metric) between two input videos.
11989 This filter takes in input two input videos, the first input is
11990 considered the "main" source and is passed unchanged to the
11991 output. The second input is used as a "reference" video for computing
11994 Both video inputs must have the same resolution and pixel format for
11995 this filter to work correctly. Also it assumes that both inputs
11996 have the same number of frames, which are compared one by one.
11998 The filter stores the calculated SSIM of each frame.
12000 The description of the accepted parameters follows.
12003 @item stats_file, f
12004 If specified the filter will use the named file to save the SSIM of
12005 each individual frame. When filename equals "-" the data is sent to
12009 The file printed if @var{stats_file} is selected, contains a sequence of
12010 key/value pairs of the form @var{key}:@var{value} for each compared
12013 A description of each shown parameter follows:
12017 sequential number of the input frame, starting from 1
12019 @item Y, U, V, R, G, B
12020 SSIM of the compared frames for the component specified by the suffix.
12023 SSIM of the compared frames for the whole frame.
12026 Same as above but in dB representation.
12031 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
12032 [main][ref] ssim="stats_file=stats.log" [out]
12035 On this example the input file being processed is compared with the
12036 reference file @file{ref_movie.mpg}. The SSIM of each individual frame
12037 is stored in @file{stats.log}.
12039 Another example with both psnr and ssim at same time:
12041 ffmpeg -i main.mpg -i ref.mpg -lavfi "ssim;[0:v][1:v]psnr" -f null -
12046 Convert between different stereoscopic image formats.
12048 The filters accept the following options:
12052 Set stereoscopic image format of input.
12054 Available values for input image formats are:
12057 side by side parallel (left eye left, right eye right)
12060 side by side crosseye (right eye left, left eye right)
12063 side by side parallel with half width resolution
12064 (left eye left, right eye right)
12067 side by side crosseye with half width resolution
12068 (right eye left, left eye right)
12071 above-below (left eye above, right eye below)
12074 above-below (right eye above, left eye below)
12077 above-below with half height resolution
12078 (left eye above, right eye below)
12081 above-below with half height resolution
12082 (right eye above, left eye below)
12085 alternating frames (left eye first, right eye second)
12088 alternating frames (right eye first, left eye second)
12091 interleaved rows (left eye has top row, right eye starts on next row)
12094 interleaved rows (right eye has top row, left eye starts on next row)
12097 interleaved columns, left eye first
12100 interleaved columns, right eye first
12102 Default value is @samp{sbsl}.
12106 Set stereoscopic image format of output.
12110 side by side parallel (left eye left, right eye right)
12113 side by side crosseye (right eye left, left eye right)
12116 side by side parallel with half width resolution
12117 (left eye left, right eye right)
12120 side by side crosseye with half width resolution
12121 (right eye left, left eye right)
12124 above-below (left eye above, right eye below)
12127 above-below (right eye above, left eye below)
12130 above-below with half height resolution
12131 (left eye above, right eye below)
12134 above-below with half height resolution
12135 (right eye above, left eye below)
12138 alternating frames (left eye first, right eye second)
12141 alternating frames (right eye first, left eye second)
12144 interleaved rows (left eye has top row, right eye starts on next row)
12147 interleaved rows (right eye has top row, left eye starts on next row)
12150 anaglyph red/blue gray
12151 (red filter on left eye, blue filter on right eye)
12154 anaglyph red/green gray
12155 (red filter on left eye, green filter on right eye)
12158 anaglyph red/cyan gray
12159 (red filter on left eye, cyan filter on right eye)
12162 anaglyph red/cyan half colored
12163 (red filter on left eye, cyan filter on right eye)
12166 anaglyph red/cyan color
12167 (red filter on left eye, cyan filter on right eye)
12170 anaglyph red/cyan color optimized with the least squares projection of dubois
12171 (red filter on left eye, cyan filter on right eye)
12174 anaglyph green/magenta gray
12175 (green filter on left eye, magenta filter on right eye)
12178 anaglyph green/magenta half colored
12179 (green filter on left eye, magenta filter on right eye)
12182 anaglyph green/magenta colored
12183 (green filter on left eye, magenta filter on right eye)
12186 anaglyph green/magenta color optimized with the least squares projection of dubois
12187 (green filter on left eye, magenta filter on right eye)
12190 anaglyph yellow/blue gray
12191 (yellow filter on left eye, blue filter on right eye)
12194 anaglyph yellow/blue half colored
12195 (yellow filter on left eye, blue filter on right eye)
12198 anaglyph yellow/blue colored
12199 (yellow filter on left eye, blue filter on right eye)
12202 anaglyph yellow/blue color optimized with the least squares projection of dubois
12203 (yellow filter on left eye, blue filter on right eye)
12206 mono output (left eye only)
12209 mono output (right eye only)
12212 checkerboard, left eye first
12215 checkerboard, right eye first
12218 interleaved columns, left eye first
12221 interleaved columns, right eye first
12224 Default value is @samp{arcd}.
12227 @subsection Examples
12231 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
12237 Convert input video from above below (left eye above, right eye below) to side by side crosseye.
12243 @section streamselect, astreamselect
12244 Select video or audio streams.
12246 The filter accepts the following options:
12250 Set number of inputs. Default is 2.
12253 Set input indexes to remap to outputs.
12256 @subsection Commands
12258 The @code{streamselect} and @code{astreamselect} filter supports the following
12263 Set input indexes to remap to outputs.
12266 @subsection Examples
12270 Select first 5 seconds 1st stream and rest of time 2nd stream:
12272 sendcmd='5.0 streamselect map 1',streamselect=inputs=2:map=0
12276 Same as above, but for audio:
12278 asendcmd='5.0 astreamselect map 1',astreamselect=inputs=2:map=0
12285 Apply a simple postprocessing filter that compresses and decompresses the image
12286 at several (or - in the case of @option{quality} level @code{6} - all) shifts
12287 and average the results.
12289 The filter accepts the following options:
12293 Set quality. This option defines the number of levels for averaging. It accepts
12294 an integer in the range 0-6. If set to @code{0}, the filter will have no
12295 effect. A value of @code{6} means the higher quality. For each increment of
12296 that value the speed drops by a factor of approximately 2. Default value is
12300 Force a constant quantization parameter. If not set, the filter will use the QP
12301 from the video stream (if available).
12304 Set thresholding mode. Available modes are:
12308 Set hard thresholding (default).
12310 Set soft thresholding (better de-ringing effect, but likely blurrier).
12313 @item use_bframe_qp
12314 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
12315 option may cause flicker since the B-Frames have often larger QP. Default is
12316 @code{0} (not enabled).
12322 Draw subtitles on top of input video using the libass library.
12324 To enable compilation of this filter you need to configure FFmpeg with
12325 @code{--enable-libass}. This filter also requires a build with libavcodec and
12326 libavformat to convert the passed subtitles file to ASS (Advanced Substation
12327 Alpha) subtitles format.
12329 The filter accepts the following options:
12333 Set the filename of the subtitle file to read. It must be specified.
12335 @item original_size
12336 Specify the size of the original video, the video for which the ASS file
12337 was composed. For the syntax of this option, check the
12338 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12339 Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
12340 correctly scale the fonts if the aspect ratio has been changed.
12343 Set a directory path containing fonts that can be used by the filter.
12344 These fonts will be used in addition to whatever the font provider uses.
12347 Set subtitles input character encoding. @code{subtitles} filter only. Only
12348 useful if not UTF-8.
12350 @item stream_index, si
12351 Set subtitles stream index. @code{subtitles} filter only.
12354 Override default style or script info parameters of the subtitles. It accepts a
12355 string containing ASS style format @code{KEY=VALUE} couples separated by ",".
12358 If the first key is not specified, it is assumed that the first value
12359 specifies the @option{filename}.
12361 For example, to render the file @file{sub.srt} on top of the input
12362 video, use the command:
12367 which is equivalent to:
12369 subtitles=filename=sub.srt
12372 To render the default subtitles stream from file @file{video.mkv}, use:
12374 subtitles=video.mkv
12377 To render the second subtitles stream from that file, use:
12379 subtitles=video.mkv:si=1
12382 To make the subtitles stream from @file{sub.srt} appear in transparent green
12383 @code{DejaVu Serif}, use:
12385 subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'
12388 @section super2xsai
12390 Scale the input by 2x and smooth using the Super2xSaI (Scale and
12391 Interpolate) pixel art scaling algorithm.
12393 Useful for enlarging pixel art images without reducing sharpness.
12397 Swap two rectangular objects in video.
12399 This filter accepts the following options:
12409 Set 1st rect x coordinate.
12412 Set 1st rect y coordinate.
12415 Set 2nd rect x coordinate.
12418 Set 2nd rect y coordinate.
12420 All expressions are evaluated once for each frame.
12423 The all options are expressions containing the following constants:
12428 The input width and height.
12431 same as @var{w} / @var{h}
12434 input sample aspect ratio
12437 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
12440 The number of the input frame, starting from 0.
12443 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
12446 the position in the file of the input frame, NAN if unknown
12454 Apply telecine process to the video.
12456 This filter accepts the following options:
12465 The default value is @code{top}.
12469 A string of numbers representing the pulldown pattern you wish to apply.
12470 The default value is @code{23}.
12474 Some typical patterns:
12479 24p: 2332 (preferred)
12486 24p: 222222222223 ("Euro pulldown")
12492 Select the most representative frame in a given sequence of consecutive frames.
12494 The filter accepts the following options:
12498 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
12499 will pick one of them, and then handle the next batch of @var{n} frames until
12500 the end. Default is @code{100}.
12503 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
12504 value will result in a higher memory usage, so a high value is not recommended.
12506 @subsection Examples
12510 Extract one picture each 50 frames:
12516 Complete example of a thumbnail creation with @command{ffmpeg}:
12518 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
12524 Tile several successive frames together.
12526 The filter accepts the following options:
12531 Set the grid size (i.e. the number of lines and columns). For the syntax of
12532 this option, check the
12533 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12536 Set the maximum number of frames to render in the given area. It must be less
12537 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
12538 the area will be used.
12541 Set the outer border margin in pixels.
12544 Set the inner border thickness (i.e. the number of pixels between frames). For
12545 more advanced padding options (such as having different values for the edges),
12546 refer to the pad video filter.
12549 Specify the color of the unused area. For the syntax of this option, check the
12550 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
12554 @subsection Examples
12558 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
12560 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
12562 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
12563 duplicating each output frame to accommodate the originally detected frame
12567 Display @code{5} pictures in an area of @code{3x2} frames,
12568 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
12569 mixed flat and named options:
12571 tile=3x2:nb_frames=5:padding=7:margin=2
12575 @section tinterlace
12577 Perform various types of temporal field interlacing.
12579 Frames are counted starting from 1, so the first input frame is
12582 The filter accepts the following options:
12587 Specify the mode of the interlacing. This option can also be specified
12588 as a value alone. See below for a list of values for this option.
12590 Available values are:
12594 Move odd frames into the upper field, even into the lower field,
12595 generating a double height frame at half frame rate.
12599 Frame 1 Frame 2 Frame 3 Frame 4
12601 11111 22222 33333 44444
12602 11111 22222 33333 44444
12603 11111 22222 33333 44444
12604 11111 22222 33333 44444
12618 Only output even frames, odd frames are dropped, generating a frame with
12619 unchanged height at half frame rate.
12624 Frame 1 Frame 2 Frame 3 Frame 4
12626 11111 22222 33333 44444
12627 11111 22222 33333 44444
12628 11111 22222 33333 44444
12629 11111 22222 33333 44444
12639 Only output odd frames, even frames are dropped, generating a frame with
12640 unchanged height at half frame rate.
12645 Frame 1 Frame 2 Frame 3 Frame 4
12647 11111 22222 33333 44444
12648 11111 22222 33333 44444
12649 11111 22222 33333 44444
12650 11111 22222 33333 44444
12660 Expand each frame to full height, but pad alternate lines with black,
12661 generating a frame with double height at the same input frame rate.
12666 Frame 1 Frame 2 Frame 3 Frame 4
12668 11111 22222 33333 44444
12669 11111 22222 33333 44444
12670 11111 22222 33333 44444
12671 11111 22222 33333 44444
12674 11111 ..... 33333 .....
12675 ..... 22222 ..... 44444
12676 11111 ..... 33333 .....
12677 ..... 22222 ..... 44444
12678 11111 ..... 33333 .....
12679 ..... 22222 ..... 44444
12680 11111 ..... 33333 .....
12681 ..... 22222 ..... 44444
12685 @item interleave_top, 4
12686 Interleave the upper field from odd frames with the lower field from
12687 even frames, generating a frame with unchanged height at half frame rate.
12692 Frame 1 Frame 2 Frame 3 Frame 4
12694 11111<- 22222 33333<- 44444
12695 11111 22222<- 33333 44444<-
12696 11111<- 22222 33333<- 44444
12697 11111 22222<- 33333 44444<-
12707 @item interleave_bottom, 5
12708 Interleave the lower field from odd frames with the upper field from
12709 even frames, generating a frame with unchanged height at half frame rate.
12714 Frame 1 Frame 2 Frame 3 Frame 4
12716 11111 22222<- 33333 44444<-
12717 11111<- 22222 33333<- 44444
12718 11111 22222<- 33333 44444<-
12719 11111<- 22222 33333<- 44444
12729 @item interlacex2, 6
12730 Double frame rate with unchanged height. Frames are inserted each
12731 containing the second temporal field from the previous input frame and
12732 the first temporal field from the next input frame. This mode relies on
12733 the top_field_first flag. Useful for interlaced video displays with no
12734 field synchronisation.
12739 Frame 1 Frame 2 Frame 3 Frame 4
12741 11111 22222 33333 44444
12742 11111 22222 33333 44444
12743 11111 22222 33333 44444
12744 11111 22222 33333 44444
12747 11111 22222 22222 33333 33333 44444 44444
12748 11111 11111 22222 22222 33333 33333 44444
12749 11111 22222 22222 33333 33333 44444 44444
12750 11111 11111 22222 22222 33333 33333 44444
12754 Move odd frames into the upper field, even into the lower field,
12755 generating a double height frame at same frame rate.
12759 Frame 1 Frame 2 Frame 3 Frame 4
12761 11111 22222 33333 44444
12762 11111 22222 33333 44444
12763 11111 22222 33333 44444
12764 11111 22222 33333 44444
12767 11111 33333 33333 55555
12768 22222 22222 44444 44444
12769 11111 33333 33333 55555
12770 22222 22222 44444 44444
12771 11111 33333 33333 55555
12772 22222 22222 44444 44444
12773 11111 33333 33333 55555
12774 22222 22222 44444 44444
12779 Numeric values are deprecated but are accepted for backward
12780 compatibility reasons.
12782 Default mode is @code{merge}.
12785 Specify flags influencing the filter process.
12787 Available value for @var{flags} is:
12790 @item low_pass_filter, vlfp
12791 Enable vertical low-pass filtering in the filter.
12792 Vertical low-pass filtering is required when creating an interlaced
12793 destination from a progressive source which contains high-frequency
12794 vertical detail. Filtering will reduce interlace 'twitter' and Moire
12797 Vertical low-pass filtering can only be enabled for @option{mode}
12798 @var{interleave_top} and @var{interleave_bottom}.
12805 Transpose rows with columns in the input video and optionally flip it.
12807 It accepts the following parameters:
12812 Specify the transposition direction.
12814 Can assume the following values:
12816 @item 0, 4, cclock_flip
12817 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
12825 Rotate by 90 degrees clockwise, that is:
12833 Rotate by 90 degrees counterclockwise, that is:
12840 @item 3, 7, clock_flip
12841 Rotate by 90 degrees clockwise and vertically flip, that is:
12849 For values between 4-7, the transposition is only done if the input
12850 video geometry is portrait and not landscape. These values are
12851 deprecated, the @code{passthrough} option should be used instead.
12853 Numerical values are deprecated, and should be dropped in favor of
12854 symbolic constants.
12857 Do not apply the transposition if the input geometry matches the one
12858 specified by the specified value. It accepts the following values:
12861 Always apply transposition.
12863 Preserve portrait geometry (when @var{height} >= @var{width}).
12865 Preserve landscape geometry (when @var{width} >= @var{height}).
12868 Default value is @code{none}.
12871 For example to rotate by 90 degrees clockwise and preserve portrait
12874 transpose=dir=1:passthrough=portrait
12877 The command above can also be specified as:
12879 transpose=1:portrait
12883 Trim the input so that the output contains one continuous subpart of the input.
12885 It accepts the following parameters:
12888 Specify the time of the start of the kept section, i.e. the frame with the
12889 timestamp @var{start} will be the first frame in the output.
12892 Specify the time of the first frame that will be dropped, i.e. the frame
12893 immediately preceding the one with the timestamp @var{end} will be the last
12894 frame in the output.
12897 This is the same as @var{start}, except this option sets the start timestamp
12898 in timebase units instead of seconds.
12901 This is the same as @var{end}, except this option sets the end timestamp
12902 in timebase units instead of seconds.
12905 The maximum duration of the output in seconds.
12908 The number of the first frame that should be passed to the output.
12911 The number of the first frame that should be dropped.
12914 @option{start}, @option{end}, and @option{duration} are expressed as time
12915 duration specifications; see
12916 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
12917 for the accepted syntax.
12919 Note that the first two sets of the start/end options and the @option{duration}
12920 option look at the frame timestamp, while the _frame variants simply count the
12921 frames that pass through the filter. Also note that this filter does not modify
12922 the timestamps. If you wish for the output timestamps to start at zero, insert a
12923 setpts filter after the trim filter.
12925 If multiple start or end options are set, this filter tries to be greedy and
12926 keep all the frames that match at least one of the specified constraints. To keep
12927 only the part that matches all the constraints at once, chain multiple trim
12930 The defaults are such that all the input is kept. So it is possible to set e.g.
12931 just the end values to keep everything before the specified time.
12936 Drop everything except the second minute of input:
12938 ffmpeg -i INPUT -vf trim=60:120
12942 Keep only the first second:
12944 ffmpeg -i INPUT -vf trim=duration=1
12953 Sharpen or blur the input video.
12955 It accepts the following parameters:
12958 @item luma_msize_x, lx
12959 Set the luma matrix horizontal size. It must be an odd integer between
12960 3 and 63. The default value is 5.
12962 @item luma_msize_y, ly
12963 Set the luma matrix vertical size. It must be an odd integer between 3
12964 and 63. The default value is 5.
12966 @item luma_amount, la
12967 Set the luma effect strength. It must be a floating point number, reasonable
12968 values lay between -1.5 and 1.5.
12970 Negative values will blur the input video, while positive values will
12971 sharpen it, a value of zero will disable the effect.
12973 Default value is 1.0.
12975 @item chroma_msize_x, cx
12976 Set the chroma matrix horizontal size. It must be an odd integer
12977 between 3 and 63. The default value is 5.
12979 @item chroma_msize_y, cy
12980 Set the chroma matrix vertical size. It must be an odd integer
12981 between 3 and 63. The default value is 5.
12983 @item chroma_amount, ca
12984 Set the chroma effect strength. It must be a floating point number, reasonable
12985 values lay between -1.5 and 1.5.
12987 Negative values will blur the input video, while positive values will
12988 sharpen it, a value of zero will disable the effect.
12990 Default value is 0.0.
12993 If set to 1, specify using OpenCL capabilities, only available if
12994 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
12998 All parameters are optional and default to the equivalent of the
12999 string '5:5:1.0:5:5:0.0'.
13001 @subsection Examples
13005 Apply strong luma sharpen effect:
13007 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
13011 Apply a strong blur of both luma and chroma parameters:
13013 unsharp=7:7:-2:7:7:-2
13019 Apply ultra slow/simple postprocessing filter that compresses and decompresses
13020 the image at several (or - in the case of @option{quality} level @code{8} - all)
13021 shifts and average the results.
13023 The way this differs from the behavior of spp is that uspp actually encodes &
13024 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
13025 DCT similar to MJPEG.
13027 The filter accepts the following options:
13031 Set quality. This option defines the number of levels for averaging. It accepts
13032 an integer in the range 0-8. If set to @code{0}, the filter will have no
13033 effect. A value of @code{8} means the higher quality. For each increment of
13034 that value the speed drops by a factor of approximately 2. Default value is
13038 Force a constant quantization parameter. If not set, the filter will use the QP
13039 from the video stream (if available).
13042 @section vectorscope
13044 Display 2 color component values in the two dimensional graph (which is called
13047 This filter accepts the following options:
13051 Set vectorscope mode.
13053 It accepts the following values:
13056 Gray values are displayed on graph, higher brightness means more pixels have
13057 same component color value on location in graph. This is the default mode.
13060 Gray values are displayed on graph. Surrounding pixels values which are not
13061 present in video frame are drawn in gradient of 2 color components which are
13062 set by option @code{x} and @code{y}. The 3rd color component is static.
13065 Actual color components values present in video frame are displayed on graph.
13068 Similar as color2 but higher frequency of same values @code{x} and @code{y}
13069 on graph increases value of another color component, which is luminance by
13070 default values of @code{x} and @code{y}.
13073 Actual colors present in video frame are displayed on graph. If two different
13074 colors map to same position on graph then color with higher value of component
13075 not present in graph is picked.
13078 Gray values are displayed on graph. Similar to @code{color} but with 3rd color
13079 component picked from radial gradient.
13083 Set which color component will be represented on X-axis. Default is @code{1}.
13086 Set which color component will be represented on Y-axis. Default is @code{2}.
13089 Set intensity, used by modes: gray, color, color3 and color5 for increasing brightness
13090 of color component which represents frequency of (X, Y) location in graph.
13095 No envelope, this is default.
13098 Instant envelope, even darkest single pixel will be clearly highlighted.
13101 Hold maximum and minimum values presented in graph over time. This way you
13102 can still spot out of range values without constantly looking at vectorscope.
13105 Peak and instant envelope combined together.
13109 Set what kind of graticule to draw.
13117 Set graticule opacity.
13120 Set graticule flags.
13124 Draw graticule for white point.
13127 Draw graticule for black point.
13130 Draw color points short names.
13134 Set background opacity.
13136 @item lthreshold, l
13137 Set low threshold for color component not represented on X or Y axis.
13138 Values lower than this value will be ignored. Default is 0.
13139 Note this value is multiplied with actual max possible value one pixel component
13140 can have. So for 8-bit input and low threshold value of 0.1 actual threshold
13143 @item hthreshold, h
13144 Set high threshold for color component not represented on X or Y axis.
13145 Values higher than this value will be ignored. Default is 1.
13146 Note this value is multiplied with actual max possible value one pixel component
13147 can have. So for 8-bit input and high threshold value of 0.9 actual threshold
13148 is 0.9 * 255 = 230.
13150 @item colorspace, c
13151 Set what kind of colorspace to use when drawing graticule.
13160 @anchor{vidstabdetect}
13161 @section vidstabdetect
13163 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
13164 @ref{vidstabtransform} for pass 2.
13166 This filter generates a file with relative translation and rotation
13167 transform information about subsequent frames, which is then used by
13168 the @ref{vidstabtransform} filter.
13170 To enable compilation of this filter you need to configure FFmpeg with
13171 @code{--enable-libvidstab}.
13173 This filter accepts the following options:
13177 Set the path to the file used to write the transforms information.
13178 Default value is @file{transforms.trf}.
13181 Set how shaky the video is and how quick the camera is. It accepts an
13182 integer in the range 1-10, a value of 1 means little shakiness, a
13183 value of 10 means strong shakiness. Default value is 5.
13186 Set the accuracy of the detection process. It must be a value in the
13187 range 1-15. A value of 1 means low accuracy, a value of 15 means high
13188 accuracy. Default value is 15.
13191 Set stepsize of the search process. The region around minimum is
13192 scanned with 1 pixel resolution. Default value is 6.
13195 Set minimum contrast. Below this value a local measurement field is
13196 discarded. Must be a floating point value in the range 0-1. Default
13200 Set reference frame number for tripod mode.
13202 If enabled, the motion of the frames is compared to a reference frame
13203 in the filtered stream, identified by the specified number. The idea
13204 is to compensate all movements in a more-or-less static scene and keep
13205 the camera view absolutely still.
13207 If set to 0, it is disabled. The frames are counted starting from 1.
13210 Show fields and transforms in the resulting frames. It accepts an
13211 integer in the range 0-2. Default value is 0, which disables any
13215 @subsection Examples
13219 Use default values:
13225 Analyze strongly shaky movie and put the results in file
13226 @file{mytransforms.trf}:
13228 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
13232 Visualize the result of internal transformations in the resulting
13235 vidstabdetect=show=1
13239 Analyze a video with medium shakiness using @command{ffmpeg}:
13241 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
13245 @anchor{vidstabtransform}
13246 @section vidstabtransform
13248 Video stabilization/deshaking: pass 2 of 2,
13249 see @ref{vidstabdetect} for pass 1.
13251 Read a file with transform information for each frame and
13252 apply/compensate them. Together with the @ref{vidstabdetect}
13253 filter this can be used to deshake videos. See also
13254 @url{http://public.hronopik.de/vid.stab}. It is important to also use
13255 the @ref{unsharp} filter, see below.
13257 To enable compilation of this filter you need to configure FFmpeg with
13258 @code{--enable-libvidstab}.
13260 @subsection Options
13264 Set path to the file used to read the transforms. Default value is
13265 @file{transforms.trf}.
13268 Set the number of frames (value*2 + 1) used for lowpass filtering the
13269 camera movements. Default value is 10.
13271 For example a number of 10 means that 21 frames are used (10 in the
13272 past and 10 in the future) to smoothen the motion in the video. A
13273 larger value leads to a smoother video, but limits the acceleration of
13274 the camera (pan/tilt movements). 0 is a special case where a static
13275 camera is simulated.
13278 Set the camera path optimization algorithm.
13280 Accepted values are:
13283 gaussian kernel low-pass filter on camera motion (default)
13285 averaging on transformations
13289 Set maximal number of pixels to translate frames. Default value is -1,
13293 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
13294 value is -1, meaning no limit.
13297 Specify how to deal with borders that may be visible due to movement
13300 Available values are:
13303 keep image information from previous frame (default)
13305 fill the border black
13309 Invert transforms if set to 1. Default value is 0.
13312 Consider transforms as relative to previous frame if set to 1,
13313 absolute if set to 0. Default value is 0.
13316 Set percentage to zoom. A positive value will result in a zoom-in
13317 effect, a negative value in a zoom-out effect. Default value is 0 (no
13321 Set optimal zooming to avoid borders.
13323 Accepted values are:
13328 optimal static zoom value is determined (only very strong movements
13329 will lead to visible borders) (default)
13331 optimal adaptive zoom value is determined (no borders will be
13332 visible), see @option{zoomspeed}
13335 Note that the value given at zoom is added to the one calculated here.
13338 Set percent to zoom maximally each frame (enabled when
13339 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
13343 Specify type of interpolation.
13345 Available values are:
13350 linear only horizontal
13352 linear in both directions (default)
13354 cubic in both directions (slow)
13358 Enable virtual tripod mode if set to 1, which is equivalent to
13359 @code{relative=0:smoothing=0}. Default value is 0.
13361 Use also @code{tripod} option of @ref{vidstabdetect}.
13364 Increase log verbosity if set to 1. Also the detected global motions
13365 are written to the temporary file @file{global_motions.trf}. Default
13369 @subsection Examples
13373 Use @command{ffmpeg} for a typical stabilization with default values:
13375 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
13378 Note the use of the @ref{unsharp} filter which is always recommended.
13381 Zoom in a bit more and load transform data from a given file:
13383 vidstabtransform=zoom=5:input="mytransforms.trf"
13387 Smoothen the video even more:
13389 vidstabtransform=smoothing=30
13395 Flip the input video vertically.
13397 For example, to vertically flip a video with @command{ffmpeg}:
13399 ffmpeg -i in.avi -vf "vflip" out.avi
13405 Make or reverse a natural vignetting effect.
13407 The filter accepts the following options:
13411 Set lens angle expression as a number of radians.
13413 The value is clipped in the @code{[0,PI/2]} range.
13415 Default value: @code{"PI/5"}
13419 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
13423 Set forward/backward mode.
13425 Available modes are:
13428 The larger the distance from the central point, the darker the image becomes.
13431 The larger the distance from the central point, the brighter the image becomes.
13432 This can be used to reverse a vignette effect, though there is no automatic
13433 detection to extract the lens @option{angle} and other settings (yet). It can
13434 also be used to create a burning effect.
13437 Default value is @samp{forward}.
13440 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
13442 It accepts the following values:
13445 Evaluate expressions only once during the filter initialization.
13448 Evaluate expressions for each incoming frame. This is way slower than the
13449 @samp{init} mode since it requires all the scalers to be re-computed, but it
13450 allows advanced dynamic expressions.
13453 Default value is @samp{init}.
13456 Set dithering to reduce the circular banding effects. Default is @code{1}
13460 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
13461 Setting this value to the SAR of the input will make a rectangular vignetting
13462 following the dimensions of the video.
13464 Default is @code{1/1}.
13467 @subsection Expressions
13469 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
13470 following parameters.
13475 input width and height
13478 the number of input frame, starting from 0
13481 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
13482 @var{TB} units, NAN if undefined
13485 frame rate of the input video, NAN if the input frame rate is unknown
13488 the PTS (Presentation TimeStamp) of the filtered video frame,
13489 expressed in seconds, NAN if undefined
13492 time base of the input video
13496 @subsection Examples
13500 Apply simple strong vignetting effect:
13506 Make a flickering vignetting:
13508 vignette='PI/4+random(1)*PI/50':eval=frame
13514 Stack input videos vertically.
13516 All streams must be of same pixel format and of same width.
13518 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
13519 to create same output.
13521 The filter accept the following option:
13525 Set number of input streams. Default is 2.
13528 If set to 1, force the output to terminate when the shortest input
13529 terminates. Default value is 0.
13534 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
13535 Deinterlacing Filter").
13537 Based on the process described by Martin Weston for BBC R&D, and
13538 implemented based on the de-interlace algorithm written by Jim
13539 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
13540 uses filter coefficients calculated by BBC R&D.
13542 There are two sets of filter coefficients, so called "simple":
13543 and "complex". Which set of filter coefficients is used can
13544 be set by passing an optional parameter:
13548 Set the interlacing filter coefficients. Accepts one of the following values:
13552 Simple filter coefficient set.
13554 More-complex filter coefficient set.
13556 Default value is @samp{complex}.
13559 Specify which frames to deinterlace. Accept one of the following values:
13563 Deinterlace all frames,
13565 Only deinterlace frames marked as interlaced.
13568 Default value is @samp{all}.
13572 Video waveform monitor.
13574 The waveform monitor plots color component intensity. By default luminance
13575 only. Each column of the waveform corresponds to a column of pixels in the
13578 It accepts the following options:
13582 Can be either @code{row}, or @code{column}. Default is @code{column}.
13583 In row mode, the graph on the left side represents color component value 0 and
13584 the right side represents value = 255. In column mode, the top side represents
13585 color component value = 0 and bottom side represents value = 255.
13588 Set intensity. Smaller values are useful to find out how many values of the same
13589 luminance are distributed across input rows/columns.
13590 Default value is @code{0.04}. Allowed range is [0, 1].
13593 Set mirroring mode. @code{0} means unmirrored, @code{1} means mirrored.
13594 In mirrored mode, higher values will be represented on the left
13595 side for @code{row} mode and at the top for @code{column} mode. Default is
13596 @code{1} (mirrored).
13600 It accepts the following values:
13603 Presents information identical to that in the @code{parade}, except
13604 that the graphs representing color components are superimposed directly
13607 This display mode makes it easier to spot relative differences or similarities
13608 in overlapping areas of the color components that are supposed to be identical,
13609 such as neutral whites, grays, or blacks.
13612 Display separate graph for the color components side by side in
13613 @code{row} mode or one below the other in @code{column} mode.
13616 Display separate graph for the color components side by side in
13617 @code{column} mode or one below the other in @code{row} mode.
13619 Using this display mode makes it easy to spot color casts in the highlights
13620 and shadows of an image, by comparing the contours of the top and the bottom
13621 graphs of each waveform. Since whites, grays, and blacks are characterized
13622 by exactly equal amounts of red, green, and blue, neutral areas of the picture
13623 should display three waveforms of roughly equal width/height. If not, the
13624 correction is easy to perform by making level adjustments the three waveforms.
13626 Default is @code{stack}.
13628 @item components, c
13629 Set which color components to display. Default is 1, which means only luminance
13630 or red color component if input is in RGB colorspace. If is set for example to
13631 7 it will display all 3 (if) available color components.
13636 No envelope, this is default.
13639 Instant envelope, minimum and maximum values presented in graph will be easily
13640 visible even with small @code{step} value.
13643 Hold minimum and maximum values presented in graph across time. This way you
13644 can still spot out of range values without constantly looking at waveforms.
13647 Peak and instant envelope combined together.
13653 No filtering, this is default.
13656 Luma and chroma combined together.
13659 Similar as above, but shows difference between blue and red chroma.
13662 Displays only chroma.
13665 Displays actual color value on waveform.
13668 Similar as above, but with luma showing frequency of chroma values.
13672 Set which graticule to display.
13676 Do not display graticule.
13679 Display green graticule showing legal broadcast ranges.
13683 Set graticule opacity.
13686 Set graticule flags.
13690 Draw numbers above lines. By default enabled.
13693 Draw dots instead of lines.
13697 Set scale used for displaying graticule.
13704 Default is digital.
13708 Apply the xBR high-quality magnification filter which is designed for pixel
13709 art. It follows a set of edge-detection rules, see
13710 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
13712 It accepts the following option:
13716 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
13717 @code{3xBR} and @code{4} for @code{4xBR}.
13718 Default is @code{3}.
13724 Deinterlace the input video ("yadif" means "yet another deinterlacing
13727 It accepts the following parameters:
13733 The interlacing mode to adopt. It accepts one of the following values:
13736 @item 0, send_frame
13737 Output one frame for each frame.
13738 @item 1, send_field
13739 Output one frame for each field.
13740 @item 2, send_frame_nospatial
13741 Like @code{send_frame}, but it skips the spatial interlacing check.
13742 @item 3, send_field_nospatial
13743 Like @code{send_field}, but it skips the spatial interlacing check.
13746 The default value is @code{send_frame}.
13749 The picture field parity assumed for the input interlaced video. It accepts one
13750 of the following values:
13754 Assume the top field is first.
13756 Assume the bottom field is first.
13758 Enable automatic detection of field parity.
13761 The default value is @code{auto}.
13762 If the interlacing is unknown or the decoder does not export this information,
13763 top field first will be assumed.
13766 Specify which frames to deinterlace. Accept one of the following
13771 Deinterlace all frames.
13772 @item 1, interlaced
13773 Only deinterlace frames marked as interlaced.
13776 The default value is @code{all}.
13781 Apply Zoom & Pan effect.
13783 This filter accepts the following options:
13787 Set the zoom expression. Default is 1.
13791 Set the x and y expression. Default is 0.
13794 Set the duration expression in number of frames.
13795 This sets for how many number of frames effect will last for
13796 single input image.
13799 Set the output image size, default is 'hd720'.
13802 Set the output frame rate, default is '25'.
13805 Each expression can contain the following constants:
13824 Output frame count.
13828 Last calculated 'x' and 'y' position from 'x' and 'y' expression
13829 for current input frame.
13833 'x' and 'y' of last output frame of previous input frame or 0 when there was
13834 not yet such frame (first input frame).
13837 Last calculated zoom from 'z' expression for current input frame.
13840 Last calculated zoom of last output frame of previous input frame.
13843 Number of output frames for current input frame. Calculated from 'd' expression
13844 for each input frame.
13847 number of output frames created for previous input frame
13850 Rational number: input width / input height
13853 sample aspect ratio
13856 display aspect ratio
13860 @subsection Examples
13864 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
13866 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
13870 Zoom-in up to 1.5 and pan always at center of picture:
13872 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
13877 Scale (resize) the input video, using the z.lib library:
13878 https://github.com/sekrit-twc/zimg.
13880 The zscale filter forces the output display aspect ratio to be the same
13881 as the input, by changing the output sample aspect ratio.
13883 If the input image format is different from the format requested by
13884 the next filter, the zscale filter will convert the input to the
13887 @subsection Options
13888 The filter accepts the following options.
13893 Set the output video dimension expression. Default value is the input
13896 If the @var{width} or @var{w} is 0, the input width is used for the output.
13897 If the @var{height} or @var{h} is 0, the input height is used for the output.
13899 If one of the values is -1, the zscale filter will use a value that
13900 maintains the aspect ratio of the input image, calculated from the
13901 other specified dimension. If both of them are -1, the input size is
13904 If one of the values is -n with n > 1, the zscale filter will also use a value
13905 that maintains the aspect ratio of the input image, calculated from the other
13906 specified dimension. After that it will, however, make sure that the calculated
13907 dimension is divisible by n and adjust the value if necessary.
13909 See below for the list of accepted constants for use in the dimension
13913 Set the video size. For the syntax of this option, check the
13914 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13917 Set the dither type.
13919 Possible values are:
13924 @item error_diffusion
13930 Set the resize filter type.
13932 Possible values are:
13942 Default is bilinear.
13945 Set the color range.
13947 Possible values are:
13954 Default is same as input.
13957 Set the color primaries.
13959 Possible values are:
13969 Default is same as input.
13972 Set the transfer characteristics.
13974 Possible values are:
13985 Default is same as input.
13988 Set the colorspace matrix.
13990 Possible value are:
14001 Default is same as input.
14004 Set the input color range.
14006 Possible values are:
14013 Default is same as input.
14015 @item primariesin, pin
14016 Set the input color primaries.
14018 Possible values are:
14028 Default is same as input.
14030 @item transferin, tin
14031 Set the input transfer characteristics.
14033 Possible values are:
14044 Default is same as input.
14046 @item matrixin, min
14047 Set the input colorspace matrix.
14049 Possible value are:
14061 The values of the @option{w} and @option{h} options are expressions
14062 containing the following constants:
14067 The input width and height
14071 These are the same as @var{in_w} and @var{in_h}.
14075 The output (scaled) width and height
14079 These are the same as @var{out_w} and @var{out_h}
14082 The same as @var{iw} / @var{ih}
14085 input sample aspect ratio
14088 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
14092 horizontal and vertical input chroma subsample values. For example for the
14093 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
14097 horizontal and vertical output chroma subsample values. For example for the
14098 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
14104 @c man end VIDEO FILTERS
14106 @chapter Video Sources
14107 @c man begin VIDEO SOURCES
14109 Below is a description of the currently available video sources.
14113 Buffer video frames, and make them available to the filter chain.
14115 This source is mainly intended for a programmatic use, in particular
14116 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
14118 It accepts the following parameters:
14123 Specify the size (width and height) of the buffered video frames. For the
14124 syntax of this option, check the
14125 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14128 The input video width.
14131 The input video height.
14134 A string representing the pixel format of the buffered video frames.
14135 It may be a number corresponding to a pixel format, or a pixel format
14139 Specify the timebase assumed by the timestamps of the buffered frames.
14142 Specify the frame rate expected for the video stream.
14144 @item pixel_aspect, sar
14145 The sample (pixel) aspect ratio of the input video.
14148 Specify the optional parameters to be used for the scale filter which
14149 is automatically inserted when an input change is detected in the
14150 input size or format.
14152 @item hw_frames_ctx
14153 When using a hardware pixel format, this should be a reference to an
14154 AVHWFramesContext describing input frames.
14159 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
14162 will instruct the source to accept video frames with size 320x240 and
14163 with format "yuv410p", assuming 1/24 as the timestamps timebase and
14164 square pixels (1:1 sample aspect ratio).
14165 Since the pixel format with name "yuv410p" corresponds to the number 6
14166 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
14167 this example corresponds to:
14169 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
14172 Alternatively, the options can be specified as a flat string, but this
14173 syntax is deprecated:
14175 @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}]
14179 Create a pattern generated by an elementary cellular automaton.
14181 The initial state of the cellular automaton can be defined through the
14182 @option{filename}, and @option{pattern} options. If such options are
14183 not specified an initial state is created randomly.
14185 At each new frame a new row in the video is filled with the result of
14186 the cellular automaton next generation. The behavior when the whole
14187 frame is filled is defined by the @option{scroll} option.
14189 This source accepts the following options:
14193 Read the initial cellular automaton state, i.e. the starting row, from
14194 the specified file.
14195 In the file, each non-whitespace character is considered an alive
14196 cell, a newline will terminate the row, and further characters in the
14197 file will be ignored.
14200 Read the initial cellular automaton state, i.e. the starting row, from
14201 the specified string.
14203 Each non-whitespace character in the string is considered an alive
14204 cell, a newline will terminate the row, and further characters in the
14205 string will be ignored.
14208 Set the video rate, that is the number of frames generated per second.
14211 @item random_fill_ratio, ratio
14212 Set the random fill ratio for the initial cellular automaton row. It
14213 is a floating point number value ranging from 0 to 1, defaults to
14216 This option is ignored when a file or a pattern is specified.
14218 @item random_seed, seed
14219 Set the seed for filling randomly the initial row, must be an integer
14220 included between 0 and UINT32_MAX. If not specified, or if explicitly
14221 set to -1, the filter will try to use a good random seed on a best
14225 Set the cellular automaton rule, it is a number ranging from 0 to 255.
14226 Default value is 110.
14229 Set the size of the output video. For the syntax of this option, check the
14230 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14232 If @option{filename} or @option{pattern} is specified, the size is set
14233 by default to the width of the specified initial state row, and the
14234 height is set to @var{width} * PHI.
14236 If @option{size} is set, it must contain the width of the specified
14237 pattern string, and the specified pattern will be centered in the
14240 If a filename or a pattern string is not specified, the size value
14241 defaults to "320x518" (used for a randomly generated initial state).
14244 If set to 1, scroll the output upward when all the rows in the output
14245 have been already filled. If set to 0, the new generated row will be
14246 written over the top row just after the bottom row is filled.
14249 @item start_full, full
14250 If set to 1, completely fill the output with generated rows before
14251 outputting the first frame.
14252 This is the default behavior, for disabling set the value to 0.
14255 If set to 1, stitch the left and right row edges together.
14256 This is the default behavior, for disabling set the value to 0.
14259 @subsection Examples
14263 Read the initial state from @file{pattern}, and specify an output of
14266 cellauto=f=pattern:s=200x400
14270 Generate a random initial row with a width of 200 cells, with a fill
14273 cellauto=ratio=2/3:s=200x200
14277 Create a pattern generated by rule 18 starting by a single alive cell
14278 centered on an initial row with width 100:
14280 cellauto=p=@@:s=100x400:full=0:rule=18
14284 Specify a more elaborated initial pattern:
14286 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
14291 @anchor{coreimagesrc}
14292 @section coreimagesrc
14293 Video source generated on GPU using Apple's CoreImage API on OSX.
14295 This video source is a specialized version of the @ref{coreimage} video filter.
14296 Use a core image generator at the beginning of the applied filterchain to
14297 generate the content.
14299 The coreimagesrc video source accepts the following options:
14301 @item list_generators
14302 List all available generators along with all their respective options as well as
14303 possible minimum and maximum values along with the default values.
14305 list_generators=true
14309 Specify the size of the sourced video. For the syntax of this option, check the
14310 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14311 The default value is @code{320x240}.
14314 Specify the frame rate of the sourced video, as the number of frames
14315 generated per second. It has to be a string in the format
14316 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
14317 number or a valid video frame rate abbreviation. The default value is
14321 Set the sample aspect ratio of the sourced video.
14324 Set the duration of the sourced video. See
14325 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
14326 for the accepted syntax.
14328 If not specified, or the expressed duration is negative, the video is
14329 supposed to be generated forever.
14332 Additionally, all options of the @ref{coreimage} video filter are accepted.
14333 A complete filterchain can be used for further processing of the
14334 generated input without CPU-HOST transfer. See @ref{coreimage} documentation
14335 and examples for details.
14337 @subsection Examples
14342 Use CIQRCodeGenerator to create a QR code for the FFmpeg homepage,
14343 given as complete and escaped command-line for Apple's standard bash shell:
14345 ffmpeg -f lavfi -i coreimagesrc=s=100x100:filter=CIQRCodeGenerator@@inputMessage=https\\\\\://FFmpeg.org/@@inputCorrectionLevel=H -frames:v 1 QRCode.png
14347 This example is equivalent to the QRCode example of @ref{coreimage} without the
14348 need for a nullsrc video source.
14352 @section mandelbrot
14354 Generate a Mandelbrot set fractal, and progressively zoom towards the
14355 point specified with @var{start_x} and @var{start_y}.
14357 This source accepts the following options:
14362 Set the terminal pts value. Default value is 400.
14365 Set the terminal scale value.
14366 Must be a floating point value. Default value is 0.3.
14369 Set the inner coloring mode, that is the algorithm used to draw the
14370 Mandelbrot fractal internal region.
14372 It shall assume one of the following values:
14377 Show time until convergence.
14379 Set color based on point closest to the origin of the iterations.
14384 Default value is @var{mincol}.
14387 Set the bailout value. Default value is 10.0.
14390 Set the maximum of iterations performed by the rendering
14391 algorithm. Default value is 7189.
14394 Set outer coloring mode.
14395 It shall assume one of following values:
14397 @item iteration_count
14398 Set iteration cound mode.
14399 @item normalized_iteration_count
14400 set normalized iteration count mode.
14402 Default value is @var{normalized_iteration_count}.
14405 Set frame rate, expressed as number of frames per second. Default
14409 Set frame size. For the syntax of this option, check the "Video
14410 size" section in the ffmpeg-utils manual. Default value is "640x480".
14413 Set the initial scale value. Default value is 3.0.
14416 Set the initial x position. Must be a floating point value between
14417 -100 and 100. Default value is -0.743643887037158704752191506114774.
14420 Set the initial y position. Must be a floating point value between
14421 -100 and 100. Default value is -0.131825904205311970493132056385139.
14426 Generate various test patterns, as generated by the MPlayer test filter.
14428 The size of the generated video is fixed, and is 256x256.
14429 This source is useful in particular for testing encoding features.
14431 This source accepts the following options:
14436 Specify the frame rate of the sourced video, as the number of frames
14437 generated per second. It has to be a string in the format
14438 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
14439 number or a valid video frame rate abbreviation. The default value is
14443 Set the duration of the sourced video. See
14444 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
14445 for the accepted syntax.
14447 If not specified, or the expressed duration is negative, the video is
14448 supposed to be generated forever.
14452 Set the number or the name of the test to perform. Supported tests are:
14468 Default value is "all", which will cycle through the list of all tests.
14473 mptestsrc=t=dc_luma
14476 will generate a "dc_luma" test pattern.
14478 @section frei0r_src
14480 Provide a frei0r source.
14482 To enable compilation of this filter you need to install the frei0r
14483 header and configure FFmpeg with @code{--enable-frei0r}.
14485 This source accepts the following parameters:
14490 The size of the video to generate. For the syntax of this option, check the
14491 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14494 The framerate of the generated video. It may be a string of the form
14495 @var{num}/@var{den} or a frame rate abbreviation.
14498 The name to the frei0r source to load. For more information regarding frei0r and
14499 how to set the parameters, read the @ref{frei0r} section in the video filters
14502 @item filter_params
14503 A '|'-separated list of parameters to pass to the frei0r source.
14507 For example, to generate a frei0r partik0l source with size 200x200
14508 and frame rate 10 which is overlaid on the overlay filter main input:
14510 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
14515 Generate a life pattern.
14517 This source is based on a generalization of John Conway's life game.
14519 The sourced input represents a life grid, each pixel represents a cell
14520 which can be in one of two possible states, alive or dead. Every cell
14521 interacts with its eight neighbours, which are the cells that are
14522 horizontally, vertically, or diagonally adjacent.
14524 At each interaction the grid evolves according to the adopted rule,
14525 which specifies the number of neighbor alive cells which will make a
14526 cell stay alive or born. The @option{rule} option allows one to specify
14529 This source accepts the following options:
14533 Set the file from which to read the initial grid state. In the file,
14534 each non-whitespace character is considered an alive cell, and newline
14535 is used to delimit the end of each row.
14537 If this option is not specified, the initial grid is generated
14541 Set the video rate, that is the number of frames generated per second.
14544 @item random_fill_ratio, ratio
14545 Set the random fill ratio for the initial random grid. It is a
14546 floating point number value ranging from 0 to 1, defaults to 1/PHI.
14547 It is ignored when a file is specified.
14549 @item random_seed, seed
14550 Set the seed for filling the initial random grid, must be an integer
14551 included between 0 and UINT32_MAX. If not specified, or if explicitly
14552 set to -1, the filter will try to use a good random seed on a best
14558 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
14559 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
14560 @var{NS} specifies the number of alive neighbor cells which make a
14561 live cell stay alive, and @var{NB} the number of alive neighbor cells
14562 which make a dead cell to become alive (i.e. to "born").
14563 "s" and "b" can be used in place of "S" and "B", respectively.
14565 Alternatively a rule can be specified by an 18-bits integer. The 9
14566 high order bits are used to encode the next cell state if it is alive
14567 for each number of neighbor alive cells, the low order bits specify
14568 the rule for "borning" new cells. Higher order bits encode for an
14569 higher number of neighbor cells.
14570 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
14571 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
14573 Default value is "S23/B3", which is the original Conway's game of life
14574 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
14575 cells, and will born a new cell if there are three alive cells around
14579 Set the size of the output video. For the syntax of this option, check the
14580 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14582 If @option{filename} is specified, the size is set by default to the
14583 same size of the input file. If @option{size} is set, it must contain
14584 the size specified in the input file, and the initial grid defined in
14585 that file is centered in the larger resulting area.
14587 If a filename is not specified, the size value defaults to "320x240"
14588 (used for a randomly generated initial grid).
14591 If set to 1, stitch the left and right grid edges together, and the
14592 top and bottom edges also. Defaults to 1.
14595 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
14596 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
14597 value from 0 to 255.
14600 Set the color of living (or new born) cells.
14603 Set the color of dead cells. If @option{mold} is set, this is the first color
14604 used to represent a dead cell.
14607 Set mold color, for definitely dead and moldy cells.
14609 For the syntax of these 3 color options, check the "Color" section in the
14610 ffmpeg-utils manual.
14613 @subsection Examples
14617 Read a grid from @file{pattern}, and center it on a grid of size
14620 life=f=pattern:s=300x300
14624 Generate a random grid of size 200x200, with a fill ratio of 2/3:
14626 life=ratio=2/3:s=200x200
14630 Specify a custom rule for evolving a randomly generated grid:
14636 Full example with slow death effect (mold) using @command{ffplay}:
14638 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
14645 @anchor{haldclutsrc}
14647 @anchor{rgbtestsrc}
14649 @anchor{smptehdbars}
14652 @section allrgb, allyuv, color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc, testsrc2
14654 The @code{allrgb} source returns frames of size 4096x4096 of all rgb colors.
14656 The @code{allyuv} source returns frames of size 4096x4096 of all yuv colors.
14658 The @code{color} source provides an uniformly colored input.
14660 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
14661 @ref{haldclut} filter.
14663 The @code{nullsrc} source returns unprocessed video frames. It is
14664 mainly useful to be employed in analysis / debugging tools, or as the
14665 source for filters which ignore the input data.
14667 The @code{rgbtestsrc} source generates an RGB test pattern useful for
14668 detecting RGB vs BGR issues. You should see a red, green and blue
14669 stripe from top to bottom.
14671 The @code{smptebars} source generates a color bars pattern, based on
14672 the SMPTE Engineering Guideline EG 1-1990.
14674 The @code{smptehdbars} source generates a color bars pattern, based on
14675 the SMPTE RP 219-2002.
14677 The @code{testsrc} source generates a test video pattern, showing a
14678 color pattern, a scrolling gradient and a timestamp. This is mainly
14679 intended for testing purposes.
14681 The @code{testsrc2} source is similar to testsrc, but supports more
14682 pixel formats instead of just @code{rgb24}. This allows using it as an
14683 input for other tests without requiring a format conversion.
14685 The sources accept the following parameters:
14690 Specify the color of the source, only available in the @code{color}
14691 source. For the syntax of this option, check the "Color" section in the
14692 ffmpeg-utils manual.
14695 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
14696 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
14697 pixels to be used as identity matrix for 3D lookup tables. Each component is
14698 coded on a @code{1/(N*N)} scale.
14701 Specify the size of the sourced video. For the syntax of this option, check the
14702 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14703 The default value is @code{320x240}.
14705 This option is not available with the @code{haldclutsrc} filter.
14708 Specify the frame rate of the sourced video, as the number of frames
14709 generated per second. It has to be a string in the format
14710 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
14711 number or a valid video frame rate abbreviation. The default value is
14715 Set the sample aspect ratio of the sourced video.
14718 Set the duration of the sourced video. See
14719 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
14720 for the accepted syntax.
14722 If not specified, or the expressed duration is negative, the video is
14723 supposed to be generated forever.
14726 Set the number of decimals to show in the timestamp, only available in the
14727 @code{testsrc} source.
14729 The displayed timestamp value will correspond to the original
14730 timestamp value multiplied by the power of 10 of the specified
14731 value. Default value is 0.
14734 For example the following:
14736 testsrc=duration=5.3:size=qcif:rate=10
14739 will generate a video with a duration of 5.3 seconds, with size
14740 176x144 and a frame rate of 10 frames per second.
14742 The following graph description will generate a red source
14743 with an opacity of 0.2, with size "qcif" and a frame rate of 10
14746 color=c=red@@0.2:s=qcif:r=10
14749 If the input content is to be ignored, @code{nullsrc} can be used. The
14750 following command generates noise in the luminance plane by employing
14751 the @code{geq} filter:
14753 nullsrc=s=256x256, geq=random(1)*255:128:128
14756 @subsection Commands
14758 The @code{color} source supports the following commands:
14762 Set the color of the created image. Accepts the same syntax of the
14763 corresponding @option{color} option.
14766 @c man end VIDEO SOURCES
14768 @chapter Video Sinks
14769 @c man begin VIDEO SINKS
14771 Below is a description of the currently available video sinks.
14773 @section buffersink
14775 Buffer video frames, and make them available to the end of the filter
14778 This sink is mainly intended for programmatic use, in particular
14779 through the interface defined in @file{libavfilter/buffersink.h}
14780 or the options system.
14782 It accepts a pointer to an AVBufferSinkContext structure, which
14783 defines the incoming buffers' formats, to be passed as the opaque
14784 parameter to @code{avfilter_init_filter} for initialization.
14788 Null video sink: do absolutely nothing with the input video. It is
14789 mainly useful as a template and for use in analysis / debugging
14792 @c man end VIDEO SINKS
14794 @chapter Multimedia Filters
14795 @c man begin MULTIMEDIA FILTERS
14797 Below is a description of the currently available multimedia filters.
14799 @section ahistogram
14801 Convert input audio to a video output, displaying the volume histogram.
14803 The filter accepts the following options:
14807 Specify how histogram is calculated.
14809 It accepts the following values:
14812 Use single histogram for all channels.
14814 Use separate histogram for each channel.
14816 Default is @code{single}.
14819 Set frame rate, expressed as number of frames per second. Default
14823 Specify the video size for the output. For the syntax of this option, check the
14824 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14825 Default value is @code{hd720}.
14830 It accepts the following values:
14841 reverse logarithmic
14843 Default is @code{log}.
14846 Set amplitude scale.
14848 It accepts the following values:
14855 Default is @code{log}.
14858 Set how much frames to accumulate in histogram.
14859 Defauls is 1. Setting this to -1 accumulates all frames.
14862 Set histogram ratio of window height.
14865 Set sonogram sliding.
14867 It accepts the following values:
14870 replace old rows with new ones.
14872 scroll from top to bottom.
14874 Default is @code{replace}.
14877 @section aphasemeter
14879 Convert input audio to a video output, displaying the audio phase.
14881 The filter accepts the following options:
14885 Set the output frame rate. Default value is @code{25}.
14888 Set the video size for the output. For the syntax of this option, check the
14889 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14890 Default value is @code{800x400}.
14895 Specify the red, green, blue contrast. Default values are @code{2},
14896 @code{7} and @code{1}.
14897 Allowed range is @code{[0, 255]}.
14900 Set color which will be used for drawing median phase. If color is
14901 @code{none} which is default, no median phase value will be drawn.
14904 The filter also exports the frame metadata @code{lavfi.aphasemeter.phase} which
14905 represents mean phase of current audio frame. Value is in range @code{[-1, 1]}.
14906 The @code{-1} means left and right channels are completely out of phase and
14907 @code{1} means channels are in phase.
14909 @section avectorscope
14911 Convert input audio to a video output, representing the audio vector
14914 The filter is used to measure the difference between channels of stereo
14915 audio stream. A monoaural signal, consisting of identical left and right
14916 signal, results in straight vertical line. Any stereo separation is visible
14917 as a deviation from this line, creating a Lissajous figure.
14918 If the straight (or deviation from it) but horizontal line appears this
14919 indicates that the left and right channels are out of phase.
14921 The filter accepts the following options:
14925 Set the vectorscope mode.
14927 Available values are:
14930 Lissajous rotated by 45 degrees.
14933 Same as above but not rotated.
14936 Shape resembling half of circle.
14939 Default value is @samp{lissajous}.
14942 Set the video size for the output. For the syntax of this option, check the
14943 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14944 Default value is @code{400x400}.
14947 Set the output frame rate. Default value is @code{25}.
14953 Specify the red, green, blue and alpha contrast. Default values are @code{40},
14954 @code{160}, @code{80} and @code{255}.
14955 Allowed range is @code{[0, 255]}.
14961 Specify the red, green, blue and alpha fade. Default values are @code{15},
14962 @code{10}, @code{5} and @code{5}.
14963 Allowed range is @code{[0, 255]}.
14966 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
14969 Set the vectorscope drawing mode.
14971 Available values are:
14974 Draw dot for each sample.
14977 Draw line between previous and current sample.
14980 Default value is @samp{dot}.
14983 @subsection Examples
14987 Complete example using @command{ffplay}:
14989 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
14990 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
14994 @section bench, abench
14996 Benchmark part of a filtergraph.
14998 The filter accepts the following options:
15002 Start or stop a timer.
15004 Available values are:
15007 Get the current time, set it as frame metadata (using the key
15008 @code{lavfi.bench.start_time}), and forward the frame to the next filter.
15011 Get the current time and fetch the @code{lavfi.bench.start_time} metadata from
15012 the input frame metadata to get the time difference. Time difference, average,
15013 maximum and minimum time (respectively @code{t}, @code{avg}, @code{max} and
15014 @code{min}) are then printed. The timestamps are expressed in seconds.
15018 @subsection Examples
15022 Benchmark @ref{selectivecolor} filter:
15024 bench=start,selectivecolor=reds=-.2 .12 -.49,bench=stop
15030 Concatenate audio and video streams, joining them together one after the
15033 The filter works on segments of synchronized video and audio streams. All
15034 segments must have the same number of streams of each type, and that will
15035 also be the number of streams at output.
15037 The filter accepts the following options:
15042 Set the number of segments. Default is 2.
15045 Set the number of output video streams, that is also the number of video
15046 streams in each segment. Default is 1.
15049 Set the number of output audio streams, that is also the number of audio
15050 streams in each segment. Default is 0.
15053 Activate unsafe mode: do not fail if segments have a different format.
15057 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
15058 @var{a} audio outputs.
15060 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
15061 segment, in the same order as the outputs, then the inputs for the second
15064 Related streams do not always have exactly the same duration, for various
15065 reasons including codec frame size or sloppy authoring. For that reason,
15066 related synchronized streams (e.g. a video and its audio track) should be
15067 concatenated at once. The concat filter will use the duration of the longest
15068 stream in each segment (except the last one), and if necessary pad shorter
15069 audio streams with silence.
15071 For this filter to work correctly, all segments must start at timestamp 0.
15073 All corresponding streams must have the same parameters in all segments; the
15074 filtering system will automatically select a common pixel format for video
15075 streams, and a common sample format, sample rate and channel layout for
15076 audio streams, but other settings, such as resolution, must be converted
15077 explicitly by the user.
15079 Different frame rates are acceptable but will result in variable frame rate
15080 at output; be sure to configure the output file to handle it.
15082 @subsection Examples
15086 Concatenate an opening, an episode and an ending, all in bilingual version
15087 (video in stream 0, audio in streams 1 and 2):
15089 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
15090 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
15091 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
15092 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
15096 Concatenate two parts, handling audio and video separately, using the
15097 (a)movie sources, and adjusting the resolution:
15099 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
15100 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
15101 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
15103 Note that a desync will happen at the stitch if the audio and video streams
15104 do not have exactly the same duration in the first file.
15111 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
15112 it unchanged. By default, it logs a message at a frequency of 10Hz with the
15113 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
15114 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
15116 The filter also has a video output (see the @var{video} option) with a real
15117 time graph to observe the loudness evolution. The graphic contains the logged
15118 message mentioned above, so it is not printed anymore when this option is set,
15119 unless the verbose logging is set. The main graphing area contains the
15120 short-term loudness (3 seconds of analysis), and the gauge on the right is for
15121 the momentary loudness (400 milliseconds).
15123 More information about the Loudness Recommendation EBU R128 on
15124 @url{http://tech.ebu.ch/loudness}.
15126 The filter accepts the following options:
15131 Activate the video output. The audio stream is passed unchanged whether this
15132 option is set or no. The video stream will be the first output stream if
15133 activated. Default is @code{0}.
15136 Set the video size. This option is for video only. For the syntax of this
15138 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15139 Default and minimum resolution is @code{640x480}.
15142 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
15143 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
15144 other integer value between this range is allowed.
15147 Set metadata injection. If set to @code{1}, the audio input will be segmented
15148 into 100ms output frames, each of them containing various loudness information
15149 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
15151 Default is @code{0}.
15154 Force the frame logging level.
15156 Available values are:
15159 information logging level
15161 verbose logging level
15164 By default, the logging level is set to @var{info}. If the @option{video} or
15165 the @option{metadata} options are set, it switches to @var{verbose}.
15170 Available modes can be cumulated (the option is a @code{flag} type). Possible
15174 Disable any peak mode (default).
15176 Enable sample-peak mode.
15178 Simple peak mode looking for the higher sample value. It logs a message
15179 for sample-peak (identified by @code{SPK}).
15181 Enable true-peak mode.
15183 If enabled, the peak lookup is done on an over-sampled version of the input
15184 stream for better peak accuracy. It logs a message for true-peak.
15185 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
15186 This mode requires a build with @code{libswresample}.
15190 Treat mono input files as "dual mono". If a mono file is intended for playback
15191 on a stereo system, its EBU R128 measurement will be perceptually incorrect.
15192 If set to @code{true}, this option will compensate for this effect.
15193 Multi-channel input files are not affected by this option.
15196 Set a specific pan law to be used for the measurement of dual mono files.
15197 This parameter is optional, and has a default value of -3.01dB.
15200 @subsection Examples
15204 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
15206 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
15210 Run an analysis with @command{ffmpeg}:
15212 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
15216 @section interleave, ainterleave
15218 Temporally interleave frames from several inputs.
15220 @code{interleave} works with video inputs, @code{ainterleave} with audio.
15222 These filters read frames from several inputs and send the oldest
15223 queued frame to the output.
15225 Input streams must have a well defined, monotonically increasing frame
15228 In order to submit one frame to output, these filters need to enqueue
15229 at least one frame for each input, so they cannot work in case one
15230 input is not yet terminated and will not receive incoming frames.
15232 For example consider the case when one input is a @code{select} filter
15233 which always drop input frames. The @code{interleave} filter will keep
15234 reading from that input, but it will never be able to send new frames
15235 to output until the input will send an end-of-stream signal.
15237 Also, depending on inputs synchronization, the filters will drop
15238 frames in case one input receives more frames than the other ones, and
15239 the queue is already filled.
15241 These filters accept the following options:
15245 Set the number of different inputs, it is 2 by default.
15248 @subsection Examples
15252 Interleave frames belonging to different streams using @command{ffmpeg}:
15254 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
15258 Add flickering blur effect:
15260 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
15264 @section perms, aperms
15266 Set read/write permissions for the output frames.
15268 These filters are mainly aimed at developers to test direct path in the
15269 following filter in the filtergraph.
15271 The filters accept the following options:
15275 Select the permissions mode.
15277 It accepts the following values:
15280 Do nothing. This is the default.
15282 Set all the output frames read-only.
15284 Set all the output frames directly writable.
15286 Make the frame read-only if writable, and writable if read-only.
15288 Set each output frame read-only or writable randomly.
15292 Set the seed for the @var{random} mode, must be an integer included between
15293 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
15294 @code{-1}, the filter will try to use a good random seed on a best effort
15298 Note: in case of auto-inserted filter between the permission filter and the
15299 following one, the permission might not be received as expected in that
15300 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
15301 perms/aperms filter can avoid this problem.
15303 @section realtime, arealtime
15305 Slow down filtering to match real time approximatively.
15307 These filters will pause the filtering for a variable amount of time to
15308 match the output rate with the input timestamps.
15309 They are similar to the @option{re} option to @code{ffmpeg}.
15311 They accept the following options:
15315 Time limit for the pauses. Any pause longer than that will be considered
15316 a timestamp discontinuity and reset the timer. Default is 2 seconds.
15319 @section select, aselect
15321 Select frames to pass in output.
15323 This filter accepts the following options:
15328 Set expression, which is evaluated for each input frame.
15330 If the expression is evaluated to zero, the frame is discarded.
15332 If the evaluation result is negative or NaN, the frame is sent to the
15333 first output; otherwise it is sent to the output with index
15334 @code{ceil(val)-1}, assuming that the input index starts from 0.
15336 For example a value of @code{1.2} corresponds to the output with index
15337 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
15340 Set the number of outputs. The output to which to send the selected
15341 frame is based on the result of the evaluation. Default value is 1.
15344 The expression can contain the following constants:
15348 The (sequential) number of the filtered frame, starting from 0.
15351 The (sequential) number of the selected frame, starting from 0.
15353 @item prev_selected_n
15354 The sequential number of the last selected frame. It's NAN if undefined.
15357 The timebase of the input timestamps.
15360 The PTS (Presentation TimeStamp) of the filtered video frame,
15361 expressed in @var{TB} units. It's NAN if undefined.
15364 The PTS of the filtered video frame,
15365 expressed in seconds. It's NAN if undefined.
15368 The PTS of the previously filtered video frame. It's NAN if undefined.
15370 @item prev_selected_pts
15371 The PTS of the last previously filtered video frame. It's NAN if undefined.
15373 @item prev_selected_t
15374 The PTS of the last previously selected video frame. It's NAN if undefined.
15377 The PTS of the first video frame in the video. It's NAN if undefined.
15380 The time of the first video frame in the video. It's NAN if undefined.
15382 @item pict_type @emph{(video only)}
15383 The type of the filtered frame. It can assume one of the following
15395 @item interlace_type @emph{(video only)}
15396 The frame interlace type. It can assume one of the following values:
15399 The frame is progressive (not interlaced).
15401 The frame is top-field-first.
15403 The frame is bottom-field-first.
15406 @item consumed_sample_n @emph{(audio only)}
15407 the number of selected samples before the current frame
15409 @item samples_n @emph{(audio only)}
15410 the number of samples in the current frame
15412 @item sample_rate @emph{(audio only)}
15413 the input sample rate
15416 This is 1 if the filtered frame is a key-frame, 0 otherwise.
15419 the position in the file of the filtered frame, -1 if the information
15420 is not available (e.g. for synthetic video)
15422 @item scene @emph{(video only)}
15423 value between 0 and 1 to indicate a new scene; a low value reflects a low
15424 probability for the current frame to introduce a new scene, while a higher
15425 value means the current frame is more likely to be one (see the example below)
15427 @item concatdec_select
15428 The concat demuxer can select only part of a concat input file by setting an
15429 inpoint and an outpoint, but the output packets may not be entirely contained
15430 in the selected interval. By using this variable, it is possible to skip frames
15431 generated by the concat demuxer which are not exactly contained in the selected
15434 This works by comparing the frame pts against the @var{lavf.concat.start_time}
15435 and the @var{lavf.concat.duration} packet metadata values which are also
15436 present in the decoded frames.
15438 The @var{concatdec_select} variable is -1 if the frame pts is at least
15439 start_time and either the duration metadata is missing or the frame pts is less
15440 than start_time + duration, 0 otherwise, and NaN if the start_time metadata is
15443 That basically means that an input frame is selected if its pts is within the
15444 interval set by the concat demuxer.
15448 The default value of the select expression is "1".
15450 @subsection Examples
15454 Select all frames in input:
15459 The example above is the same as:
15471 Select only I-frames:
15473 select='eq(pict_type\,I)'
15477 Select one frame every 100:
15479 select='not(mod(n\,100))'
15483 Select only frames contained in the 10-20 time interval:
15485 select=between(t\,10\,20)
15489 Select only I frames contained in the 10-20 time interval:
15491 select=between(t\,10\,20)*eq(pict_type\,I)
15495 Select frames with a minimum distance of 10 seconds:
15497 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
15501 Use aselect to select only audio frames with samples number > 100:
15503 aselect='gt(samples_n\,100)'
15507 Create a mosaic of the first scenes:
15509 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
15512 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
15516 Send even and odd frames to separate outputs, and compose them:
15518 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
15522 Select useful frames from an ffconcat file which is using inpoints and
15523 outpoints but where the source files are not intra frame only.
15525 ffmpeg -copyts -vsync 0 -segment_time_metadata 1 -i input.ffconcat -vf select=concatdec_select -af aselect=concatdec_select output.avi
15529 @section sendcmd, asendcmd
15531 Send commands to filters in the filtergraph.
15533 These filters read commands to be sent to other filters in the
15536 @code{sendcmd} must be inserted between two video filters,
15537 @code{asendcmd} must be inserted between two audio filters, but apart
15538 from that they act the same way.
15540 The specification of commands can be provided in the filter arguments
15541 with the @var{commands} option, or in a file specified by the
15542 @var{filename} option.
15544 These filters accept the following options:
15547 Set the commands to be read and sent to the other filters.
15549 Set the filename of the commands to be read and sent to the other
15553 @subsection Commands syntax
15555 A commands description consists of a sequence of interval
15556 specifications, comprising a list of commands to be executed when a
15557 particular event related to that interval occurs. The occurring event
15558 is typically the current frame time entering or leaving a given time
15561 An interval is specified by the following syntax:
15563 @var{START}[-@var{END}] @var{COMMANDS};
15566 The time interval is specified by the @var{START} and @var{END} times.
15567 @var{END} is optional and defaults to the maximum time.
15569 The current frame time is considered within the specified interval if
15570 it is included in the interval [@var{START}, @var{END}), that is when
15571 the time is greater or equal to @var{START} and is lesser than
15574 @var{COMMANDS} consists of a sequence of one or more command
15575 specifications, separated by ",", relating to that interval. The
15576 syntax of a command specification is given by:
15578 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
15581 @var{FLAGS} is optional and specifies the type of events relating to
15582 the time interval which enable sending the specified command, and must
15583 be a non-null sequence of identifier flags separated by "+" or "|" and
15584 enclosed between "[" and "]".
15586 The following flags are recognized:
15589 The command is sent when the current frame timestamp enters the
15590 specified interval. In other words, the command is sent when the
15591 previous frame timestamp was not in the given interval, and the
15595 The command is sent when the current frame timestamp leaves the
15596 specified interval. In other words, the command is sent when the
15597 previous frame timestamp was in the given interval, and the
15601 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
15604 @var{TARGET} specifies the target of the command, usually the name of
15605 the filter class or a specific filter instance name.
15607 @var{COMMAND} specifies the name of the command for the target filter.
15609 @var{ARG} is optional and specifies the optional list of argument for
15610 the given @var{COMMAND}.
15612 Between one interval specification and another, whitespaces, or
15613 sequences of characters starting with @code{#} until the end of line,
15614 are ignored and can be used to annotate comments.
15616 A simplified BNF description of the commands specification syntax
15619 @var{COMMAND_FLAG} ::= "enter" | "leave"
15620 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
15621 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
15622 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
15623 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
15624 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
15627 @subsection Examples
15631 Specify audio tempo change at second 4:
15633 asendcmd=c='4.0 atempo tempo 1.5',atempo
15637 Specify a list of drawtext and hue commands in a file.
15639 # show text in the interval 5-10
15640 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
15641 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
15643 # desaturate the image in the interval 15-20
15644 15.0-20.0 [enter] hue s 0,
15645 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
15647 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
15649 # apply an exponential saturation fade-out effect, starting from time 25
15650 25 [enter] hue s exp(25-t)
15653 A filtergraph allowing to read and process the above command list
15654 stored in a file @file{test.cmd}, can be specified with:
15656 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
15661 @section setpts, asetpts
15663 Change the PTS (presentation timestamp) of the input frames.
15665 @code{setpts} works on video frames, @code{asetpts} on audio frames.
15667 This filter accepts the following options:
15672 The expression which is evaluated for each frame to construct its timestamp.
15676 The expression is evaluated through the eval API and can contain the following
15681 frame rate, only defined for constant frame-rate video
15684 The presentation timestamp in input
15687 The count of the input frame for video or the number of consumed samples,
15688 not including the current frame for audio, starting from 0.
15690 @item NB_CONSUMED_SAMPLES
15691 The number of consumed samples, not including the current frame (only
15694 @item NB_SAMPLES, S
15695 The number of samples in the current frame (only audio)
15697 @item SAMPLE_RATE, SR
15698 The audio sample rate.
15701 The PTS of the first frame.
15704 the time in seconds of the first frame
15707 State whether the current frame is interlaced.
15710 the time in seconds of the current frame
15713 original position in the file of the frame, or undefined if undefined
15714 for the current frame
15717 The previous input PTS.
15720 previous input time in seconds
15723 The previous output PTS.
15726 previous output time in seconds
15729 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
15733 The wallclock (RTC) time at the start of the movie in microseconds.
15736 The timebase of the input timestamps.
15740 @subsection Examples
15744 Start counting PTS from zero
15746 setpts=PTS-STARTPTS
15750 Apply fast motion effect:
15756 Apply slow motion effect:
15762 Set fixed rate of 25 frames per second:
15768 Set fixed rate 25 fps with some jitter:
15770 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
15774 Apply an offset of 10 seconds to the input PTS:
15780 Generate timestamps from a "live source" and rebase onto the current timebase:
15782 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
15786 Generate timestamps by counting samples:
15793 @section settb, asettb
15795 Set the timebase to use for the output frames timestamps.
15796 It is mainly useful for testing timebase configuration.
15798 It accepts the following parameters:
15803 The expression which is evaluated into the output timebase.
15807 The value for @option{tb} is an arithmetic expression representing a
15808 rational. The expression can contain the constants "AVTB" (the default
15809 timebase), "intb" (the input timebase) and "sr" (the sample rate,
15810 audio only). Default value is "intb".
15812 @subsection Examples
15816 Set the timebase to 1/25:
15822 Set the timebase to 1/10:
15828 Set the timebase to 1001/1000:
15834 Set the timebase to 2*intb:
15840 Set the default timebase value:
15847 Convert input audio to a video output representing frequency spectrum
15848 logarithmically using Brown-Puckette constant Q transform algorithm with
15849 direct frequency domain coefficient calculation (but the transform itself
15850 is not really constant Q, instead the Q factor is actually variable/clamped),
15851 with musical tone scale, from E0 to D#10.
15853 The filter accepts the following options:
15857 Specify the video size for the output. It must be even. For the syntax of this option,
15858 check the @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15859 Default value is @code{1920x1080}.
15862 Set the output frame rate. Default value is @code{25}.
15865 Set the bargraph height. It must be even. Default value is @code{-1} which
15866 computes the bargraph height automatically.
15869 Set the axis height. It must be even. Default value is @code{-1} which computes
15870 the axis height automatically.
15873 Set the sonogram height. It must be even. Default value is @code{-1} which
15874 computes the sonogram height automatically.
15877 Set the fullhd resolution. This option is deprecated, use @var{size}, @var{s}
15878 instead. Default value is @code{1}.
15880 @item sono_v, volume
15881 Specify the sonogram volume expression. It can contain variables:
15884 the @var{bar_v} evaluated expression
15885 @item frequency, freq, f
15886 the frequency where it is evaluated
15887 @item timeclamp, tc
15888 the value of @var{timeclamp} option
15892 @item a_weighting(f)
15893 A-weighting of equal loudness
15894 @item b_weighting(f)
15895 B-weighting of equal loudness
15896 @item c_weighting(f)
15897 C-weighting of equal loudness.
15899 Default value is @code{16}.
15901 @item bar_v, volume2
15902 Specify the bargraph volume expression. It can contain variables:
15905 the @var{sono_v} evaluated expression
15906 @item frequency, freq, f
15907 the frequency where it is evaluated
15908 @item timeclamp, tc
15909 the value of @var{timeclamp} option
15913 @item a_weighting(f)
15914 A-weighting of equal loudness
15915 @item b_weighting(f)
15916 B-weighting of equal loudness
15917 @item c_weighting(f)
15918 C-weighting of equal loudness.
15920 Default value is @code{sono_v}.
15922 @item sono_g, gamma
15923 Specify the sonogram gamma. Lower gamma makes the spectrum more contrast,
15924 higher gamma makes the spectrum having more range. Default value is @code{3}.
15925 Acceptable range is @code{[1, 7]}.
15927 @item bar_g, gamma2
15928 Specify the bargraph gamma. Default value is @code{1}. Acceptable range is
15931 @item timeclamp, tc
15932 Specify the transform timeclamp. At low frequency, there is trade-off between
15933 accuracy in time domain and frequency domain. If timeclamp is lower,
15934 event in time domain is represented more accurately (such as fast bass drum),
15935 otherwise event in frequency domain is represented more accurately
15936 (such as bass guitar). Acceptable range is @code{[0.1, 1]}. Default value is @code{0.17}.
15939 Specify the transform base frequency. Default value is @code{20.01523126408007475},
15940 which is frequency 50 cents below E0. Acceptable range is @code{[10, 100000]}.
15943 Specify the transform end frequency. Default value is @code{20495.59681441799654},
15944 which is frequency 50 cents above D#10. Acceptable range is @code{[10, 100000]}.
15947 This option is deprecated and ignored.
15950 Specify the transform length in time domain. Use this option to control accuracy
15951 trade-off between time domain and frequency domain at every frequency sample.
15952 It can contain variables:
15954 @item frequency, freq, f
15955 the frequency where it is evaluated
15956 @item timeclamp, tc
15957 the value of @var{timeclamp} option.
15959 Default value is @code{384*tc/(384+tc*f)}.
15962 Specify the transform count for every video frame. Default value is @code{6}.
15963 Acceptable range is @code{[1, 30]}.
15966 Specify the transform count for every single pixel. Default value is @code{0},
15967 which makes it computed automatically. Acceptable range is @code{[0, 10]}.
15970 Specify font file for use with freetype to draw the axis. If not specified,
15971 use embedded font. Note that drawing with font file or embedded font is not
15972 implemented with custom @var{basefreq} and @var{endfreq}, use @var{axisfile}
15976 Specify font color expression. This is arithmetic expression that should return
15977 integer value 0xRRGGBB. It can contain variables:
15979 @item frequency, freq, f
15980 the frequency where it is evaluated
15981 @item timeclamp, tc
15982 the value of @var{timeclamp} option
15987 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
15988 @item r(x), g(x), b(x)
15989 red, green, and blue value of intensity x.
15991 Default value is @code{st(0, (midi(f)-59.5)/12);
15992 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
15993 r(1-ld(1)) + b(ld(1))}.
15996 Specify image file to draw the axis. This option override @var{fontfile} and
15997 @var{fontcolor} option.
16000 Enable/disable drawing text to the axis. If it is set to @code{0}, drawing to
16001 the axis is disabled, ignoring @var{fontfile} and @var{axisfile} option.
16002 Default value is @code{1}.
16006 @subsection Examples
16010 Playing audio while showing the spectrum:
16012 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
16016 Same as above, but with frame rate 30 fps:
16018 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
16022 Playing at 1280x720:
16024 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=s=1280x720:count=4 [out0]'
16028 Disable sonogram display:
16034 A1 and its harmonics: A1, A2, (near)E3, A3:
16036 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),
16037 asplit[a][out1]; [a] showcqt [out0]'
16041 Same as above, but with more accuracy in frequency domain:
16043 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),
16044 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
16050 bar_v=10:sono_v=bar_v*a_weighting(f)
16054 Custom gamma, now spectrum is linear to the amplitude.
16060 Custom tlength equation:
16062 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)))'
16066 Custom fontcolor and fontfile, C-note is colored green, others are colored blue:
16068 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))':fontfile=myfont.ttf
16072 Custom frequency range with custom axis using image file:
16074 axisfile=myaxis.png:basefreq=40:endfreq=10000
16080 Convert input audio to video output representing the audio power spectrum.
16081 Audio amplitude is on Y-axis while frequency is on X-axis.
16083 The filter accepts the following options:
16087 Specify size of video. For the syntax of this option, check the
16088 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16089 Default is @code{1024x512}.
16093 This set how each frequency bin will be represented.
16095 It accepts the following values:
16101 Default is @code{bar}.
16104 Set amplitude scale.
16106 It accepts the following values:
16120 Default is @code{log}.
16123 Set frequency scale.
16125 It accepts the following values:
16134 Reverse logarithmic scale.
16136 Default is @code{lin}.
16141 It accepts the following values:
16157 Default is @code{w2048}
16160 Set windowing function.
16162 It accepts the following values:
16180 Default is @code{hanning}.
16183 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
16184 which means optimal overlap for selected window function will be picked.
16187 Set time averaging. Setting this to 0 will display current maximal peaks.
16188 Default is @code{1}, which means time averaging is disabled.
16191 Specify list of colors separated by space or by '|' which will be used to
16192 draw channel frequencies. Unrecognized or missing colors will be replaced
16196 Set channel display mode.
16198 It accepts the following values:
16203 Default is @code{combined}.
16207 @anchor{showspectrum}
16208 @section showspectrum
16210 Convert input audio to a video output, representing the audio frequency
16213 The filter accepts the following options:
16217 Specify the video size for the output. For the syntax of this option, check the
16218 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16219 Default value is @code{640x512}.
16222 Specify how the spectrum should slide along the window.
16224 It accepts the following values:
16227 the samples start again on the left when they reach the right
16229 the samples scroll from right to left
16231 the samples scroll from left to right
16233 frames are only produced when the samples reach the right
16236 Default value is @code{replace}.
16239 Specify display mode.
16241 It accepts the following values:
16244 all channels are displayed in the same row
16246 all channels are displayed in separate rows
16249 Default value is @samp{combined}.
16252 Specify display color mode.
16254 It accepts the following values:
16257 each channel is displayed in a separate color
16259 each channel is displayed using the same color scheme
16261 each channel is displayed using the rainbow color scheme
16263 each channel is displayed using the moreland color scheme
16265 each channel is displayed using the nebulae color scheme
16267 each channel is displayed using the fire color scheme
16269 each channel is displayed using the fiery color scheme
16271 each channel is displayed using the fruit color scheme
16273 each channel is displayed using the cool color scheme
16276 Default value is @samp{channel}.
16279 Specify scale used for calculating intensity color values.
16281 It accepts the following values:
16286 square root, default
16297 Default value is @samp{sqrt}.
16300 Set saturation modifier for displayed colors. Negative values provide
16301 alternative color scheme. @code{0} is no saturation at all.
16302 Saturation must be in [-10.0, 10.0] range.
16303 Default value is @code{1}.
16306 Set window function.
16308 It accepts the following values:
16328 Default value is @code{hann}.
16331 Set orientation of time vs frequency axis. Can be @code{vertical} or
16332 @code{horizontal}. Default is @code{vertical}.
16335 Set ratio of overlap window. Default value is @code{0}.
16336 When value is @code{1} overlap is set to recommended size for specific
16337 window function currently used.
16340 Set scale gain for calculating intensity color values.
16341 Default value is @code{1}.
16344 Set which data to display. Can be @code{magnitude}, default or @code{phase}.
16347 The usage is very similar to the showwaves filter; see the examples in that
16350 @subsection Examples
16354 Large window with logarithmic color scaling:
16356 showspectrum=s=1280x480:scale=log
16360 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
16362 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
16363 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
16367 @section showspectrumpic
16369 Convert input audio to a single video frame, representing the audio frequency
16372 The filter accepts the following options:
16376 Specify the video size for the output. For the syntax of this option, check the
16377 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16378 Default value is @code{4096x2048}.
16381 Specify display mode.
16383 It accepts the following values:
16386 all channels are displayed in the same row
16388 all channels are displayed in separate rows
16390 Default value is @samp{combined}.
16393 Specify display color mode.
16395 It accepts the following values:
16398 each channel is displayed in a separate color
16400 each channel is displayed using the same color scheme
16402 each channel is displayed using the rainbow color scheme
16404 each channel is displayed using the moreland color scheme
16406 each channel is displayed using the nebulae color scheme
16408 each channel is displayed using the fire color scheme
16410 each channel is displayed using the fiery color scheme
16412 each channel is displayed using the fruit color scheme
16414 each channel is displayed using the cool color scheme
16416 Default value is @samp{intensity}.
16419 Specify scale used for calculating intensity color values.
16421 It accepts the following values:
16426 square root, default
16436 Default value is @samp{log}.
16439 Set saturation modifier for displayed colors. Negative values provide
16440 alternative color scheme. @code{0} is no saturation at all.
16441 Saturation must be in [-10.0, 10.0] range.
16442 Default value is @code{1}.
16445 Set window function.
16447 It accepts the following values:
16466 Default value is @code{hann}.
16469 Set orientation of time vs frequency axis. Can be @code{vertical} or
16470 @code{horizontal}. Default is @code{vertical}.
16473 Set scale gain for calculating intensity color values.
16474 Default value is @code{1}.
16477 Draw time and frequency axes and legends. Default is enabled.
16480 @subsection Examples
16484 Extract an audio spectrogram of a whole audio track
16485 in a 1024x1024 picture using @command{ffmpeg}:
16487 ffmpeg -i audio.flac -lavfi showspectrumpic=s=1024x1024 spectrogram.png
16491 @section showvolume
16493 Convert input audio volume to a video output.
16495 The filter accepts the following options:
16502 Set border width, allowed range is [0, 5]. Default is 1.
16505 Set channel width, allowed range is [80, 8192]. Default is 400.
16508 Set channel height, allowed range is [1, 900]. Default is 20.
16511 Set fade, allowed range is [0.001, 1]. Default is 0.95.
16514 Set volume color expression.
16516 The expression can use the following variables:
16520 Current max volume of channel in dB.
16523 Current channel number, starting from 0.
16527 If set, displays channel names. Default is enabled.
16530 If set, displays volume values. Default is enabled.
16533 Set orientation, can be @code{horizontal} or @code{vertical},
16534 default is @code{horizontal}.
16537 Set step size, allowed range s [0, 5]. Default is 0, which means
16543 Convert input audio to a video output, representing the samples waves.
16545 The filter accepts the following options:
16549 Specify the video size for the output. For the syntax of this option, check the
16550 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16551 Default value is @code{600x240}.
16556 Available values are:
16559 Draw a point for each sample.
16562 Draw a vertical line for each sample.
16565 Draw a point for each sample and a line between them.
16568 Draw a centered vertical line for each sample.
16571 Default value is @code{point}.
16574 Set the number of samples which are printed on the same column. A
16575 larger value will decrease the frame rate. Must be a positive
16576 integer. This option can be set only if the value for @var{rate}
16577 is not explicitly specified.
16580 Set the (approximate) output frame rate. This is done by setting the
16581 option @var{n}. Default value is "25".
16583 @item split_channels
16584 Set if channels should be drawn separately or overlap. Default value is 0.
16587 Set colors separated by '|' which are going to be used for drawing of each channel.
16590 Set amplitude scale. Can be linear @code{lin} or logarithmic @code{log}.
16595 @subsection Examples
16599 Output the input file audio and the corresponding video representation
16602 amovie=a.mp3,asplit[out0],showwaves[out1]
16606 Create a synthetic signal and show it with showwaves, forcing a
16607 frame rate of 30 frames per second:
16609 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
16613 @section showwavespic
16615 Convert input audio to a single video frame, representing the samples waves.
16617 The filter accepts the following options:
16621 Specify the video size for the output. For the syntax of this option, check the
16622 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16623 Default value is @code{600x240}.
16625 @item split_channels
16626 Set if channels should be drawn separately or overlap. Default value is 0.
16629 Set colors separated by '|' which are going to be used for drawing of each channel.
16632 Set amplitude scale. Can be linear @code{lin} or logarithmic @code{log}.
16636 @subsection Examples
16640 Extract a channel split representation of the wave form of a whole audio track
16641 in a 1024x800 picture using @command{ffmpeg}:
16643 ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png
16647 Colorize the waveform with colorchannelmixer. This example will make
16648 the waveform a green color approximately RGB(66,217,150). Additional
16649 channels will be shades of this color.
16651 ffmpeg -i audio.mp3 -filter_complex "showwavespic,colorchannelmixer=rr=66/255:gg=217/255:bb=150/255" waveform.png
16655 @section spectrumsynth
16657 Sythesize audio from 2 input video spectrums, first input stream represents
16658 magnitude across time and second represents phase across time.
16659 The filter will transform from frequency domain as displayed in videos back
16660 to time domain as presented in audio output.
16662 This filter is primarly created for reversing processed @ref{showspectrum}
16663 filter outputs, but can synthesize sound from other spectrograms too.
16664 But in such case results are going to be poor if the phase data is not
16665 available, because in such cases phase data need to be recreated, usually
16666 its just recreated from random noise.
16667 For best results use gray only output (@code{channel} color mode in
16668 @ref{showspectrum} filter) and @code{log} scale for magnitude video and
16669 @code{lin} scale for phase video. To produce phase, for 2nd video, use
16670 @code{data} option. Inputs videos should generally use @code{fullframe}
16671 slide mode as that saves resources needed for decoding video.
16673 The filter accepts the following options:
16677 Specify sample rate of output audio, the sample rate of audio from which
16678 spectrum was generated may differ.
16681 Set number of channels represented in input video spectrums.
16684 Set scale which was used when generating magnitude input spectrum.
16685 Can be @code{lin} or @code{log}. Default is @code{log}.
16688 Set slide which was used when generating inputs spectrums.
16689 Can be @code{replace}, @code{scroll}, @code{fullframe} or @code{rscroll}.
16690 Default is @code{fullframe}.
16693 Set window function used for resynthesis.
16696 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
16697 which means optimal overlap for selected window function will be picked.
16700 Set orientation of input videos. Can be @code{vertical} or @code{horizontal}.
16701 Default is @code{vertical}.
16704 @subsection Examples
16708 First create magnitude and phase videos from audio, assuming audio is stereo with 44100 sample rate,
16709 then resynthesize videos back to audio with spectrumsynth:
16711 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
16712 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
16713 ffmpeg -i magnitude.nut -i phase.nut -lavfi spectrumsynth=channels=2:sample_rate=44100:win_func=hann:overlap=0.875:slide=fullframe output.flac
16717 @section split, asplit
16719 Split input into several identical outputs.
16721 @code{asplit} works with audio input, @code{split} with video.
16723 The filter accepts a single parameter which specifies the number of outputs. If
16724 unspecified, it defaults to 2.
16726 @subsection Examples
16730 Create two separate outputs from the same input:
16732 [in] split [out0][out1]
16736 To create 3 or more outputs, you need to specify the number of
16739 [in] asplit=3 [out0][out1][out2]
16743 Create two separate outputs from the same input, one cropped and
16746 [in] split [splitout1][splitout2];
16747 [splitout1] crop=100:100:0:0 [cropout];
16748 [splitout2] pad=200:200:100:100 [padout];
16752 Create 5 copies of the input audio with @command{ffmpeg}:
16754 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
16760 Receive commands sent through a libzmq client, and forward them to
16761 filters in the filtergraph.
16763 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
16764 must be inserted between two video filters, @code{azmq} between two
16767 To enable these filters you need to install the libzmq library and
16768 headers and configure FFmpeg with @code{--enable-libzmq}.
16770 For more information about libzmq see:
16771 @url{http://www.zeromq.org/}
16773 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
16774 receives messages sent through a network interface defined by the
16775 @option{bind_address} option.
16777 The received message must be in the form:
16779 @var{TARGET} @var{COMMAND} [@var{ARG}]
16782 @var{TARGET} specifies the target of the command, usually the name of
16783 the filter class or a specific filter instance name.
16785 @var{COMMAND} specifies the name of the command for the target filter.
16787 @var{ARG} is optional and specifies the optional argument list for the
16788 given @var{COMMAND}.
16790 Upon reception, the message is processed and the corresponding command
16791 is injected into the filtergraph. Depending on the result, the filter
16792 will send a reply to the client, adopting the format:
16794 @var{ERROR_CODE} @var{ERROR_REASON}
16798 @var{MESSAGE} is optional.
16800 @subsection Examples
16802 Look at @file{tools/zmqsend} for an example of a zmq client which can
16803 be used to send commands processed by these filters.
16805 Consider the following filtergraph generated by @command{ffplay}
16807 ffplay -dumpgraph 1 -f lavfi "
16808 color=s=100x100:c=red [l];
16809 color=s=100x100:c=blue [r];
16810 nullsrc=s=200x100, zmq [bg];
16811 [bg][l] overlay [bg+l];
16812 [bg+l][r] overlay=x=100 "
16815 To change the color of the left side of the video, the following
16816 command can be used:
16818 echo Parsed_color_0 c yellow | tools/zmqsend
16821 To change the right side:
16823 echo Parsed_color_1 c pink | tools/zmqsend
16826 @c man end MULTIMEDIA FILTERS
16828 @chapter Multimedia Sources
16829 @c man begin MULTIMEDIA SOURCES
16831 Below is a description of the currently available multimedia sources.
16835 This is the same as @ref{movie} source, except it selects an audio
16841 Read audio and/or video stream(s) from a movie container.
16843 It accepts the following parameters:
16847 The name of the resource to read (not necessarily a file; it can also be a
16848 device or a stream accessed through some protocol).
16850 @item format_name, f
16851 Specifies the format assumed for the movie to read, and can be either
16852 the name of a container or an input device. If not specified, the
16853 format is guessed from @var{movie_name} or by probing.
16855 @item seek_point, sp
16856 Specifies the seek point in seconds. The frames will be output
16857 starting from this seek point. The parameter is evaluated with
16858 @code{av_strtod}, so the numerical value may be suffixed by an IS
16859 postfix. The default value is "0".
16862 Specifies the streams to read. Several streams can be specified,
16863 separated by "+". The source will then have as many outputs, in the
16864 same order. The syntax is explained in the ``Stream specifiers''
16865 section in the ffmpeg manual. Two special names, "dv" and "da" specify
16866 respectively the default (best suited) video and audio stream. Default
16867 is "dv", or "da" if the filter is called as "amovie".
16869 @item stream_index, si
16870 Specifies the index of the video stream to read. If the value is -1,
16871 the most suitable video stream will be automatically selected. The default
16872 value is "-1". Deprecated. If the filter is called "amovie", it will select
16873 audio instead of video.
16876 Specifies how many times to read the stream in sequence.
16877 If the value is less than 1, the stream will be read again and again.
16878 Default value is "1".
16880 Note that when the movie is looped the source timestamps are not
16881 changed, so it will generate non monotonically increasing timestamps.
16884 It allows overlaying a second video on top of the main input of
16885 a filtergraph, as shown in this graph:
16887 input -----------> deltapts0 --> overlay --> output
16890 movie --> scale--> deltapts1 -------+
16892 @subsection Examples
16896 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
16897 on top of the input labelled "in":
16899 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
16900 [in] setpts=PTS-STARTPTS [main];
16901 [main][over] overlay=16:16 [out]
16905 Read from a video4linux2 device, and overlay it on top of the input
16908 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
16909 [in] setpts=PTS-STARTPTS [main];
16910 [main][over] overlay=16:16 [out]
16914 Read the first video stream and the audio stream with id 0x81 from
16915 dvd.vob; the video is connected to the pad named "video" and the audio is
16916 connected to the pad named "audio":
16918 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
16922 @c man end MULTIMEDIA SOURCES