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 EBU R128 loudness normalization. Includes both dynamic and linear normalization modes.
2717 Support for both single pass (livestreams, files) and double pass (files) modes.
2718 This algorithm can target IL, LRA, and maximum true peak.
2720 To enable compilation of this filter you need to configure FFmpeg with
2721 @code{--enable-libebur128}.
2723 The filter accepts the following options:
2727 Set integrated loudness target.
2728 Range is -70.0 - -5.0. Default value is -24.0.
2731 Set loudness range target.
2732 Range is 1.0 - 20.0. Default value is 7.0.
2735 Set maximum true peak.
2736 Range is -9.0 - +0.0. Default value is -2.0.
2738 @item measured_I, measured_i
2739 Measured IL of input file.
2740 Range is -99.0 - +0.0.
2742 @item measured_LRA, measured_lra
2743 Measured LRA of input file.
2744 Range is 0.0 - 99.0.
2746 @item measured_TP, measured_tp
2747 Measured true peak of input file.
2748 Range is -99.0 - +99.0.
2750 @item measured_thresh
2751 Measured threshold of input file.
2752 Range is -99.0 - +0.0.
2755 Set offset gain. Gain is applied before the true-peak limiter.
2756 Range is -99.0 - +99.0. Default is +0.0.
2759 Normalize linearly if possible.
2760 measured_I, measured_LRA, measured_TP, and measured_thresh must also
2761 to be specified in order to use this mode.
2762 Options are true or false. Default is true.
2765 Set print format for stats. Options are summary, json, or none.
2766 Default value is none.
2771 Apply a low-pass filter with 3dB point frequency.
2772 The filter can be either single-pole or double-pole (the default).
2773 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2775 The filter accepts the following options:
2779 Set frequency in Hz. Default is 500.
2782 Set number of poles. Default is 2.
2785 Set method to specify band-width of filter.
2798 Specify the band-width of a filter in width_type units.
2799 Applies only to double-pole filter.
2800 The default is 0.707q and gives a Butterworth response.
2806 Mix channels with specific gain levels. The filter accepts the output
2807 channel layout followed by a set of channels definitions.
2809 This filter is also designed to efficiently remap the channels of an audio
2812 The filter accepts parameters of the form:
2813 "@var{l}|@var{outdef}|@var{outdef}|..."
2817 output channel layout or number of channels
2820 output channel specification, of the form:
2821 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
2824 output channel to define, either a channel name (FL, FR, etc.) or a channel
2825 number (c0, c1, etc.)
2828 multiplicative coefficient for the channel, 1 leaving the volume unchanged
2831 input channel to use, see out_name for details; it is not possible to mix
2832 named and numbered input channels
2835 If the `=' in a channel specification is replaced by `<', then the gains for
2836 that specification will be renormalized so that the total is 1, thus
2837 avoiding clipping noise.
2839 @subsection Mixing examples
2841 For example, if you want to down-mix from stereo to mono, but with a bigger
2842 factor for the left channel:
2844 pan=1c|c0=0.9*c0+0.1*c1
2847 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
2848 7-channels surround:
2850 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
2853 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
2854 that should be preferred (see "-ac" option) unless you have very specific
2857 @subsection Remapping examples
2859 The channel remapping will be effective if, and only if:
2862 @item gain coefficients are zeroes or ones,
2863 @item only one input per channel output,
2866 If all these conditions are satisfied, the filter will notify the user ("Pure
2867 channel mapping detected"), and use an optimized and lossless method to do the
2870 For example, if you have a 5.1 source and want a stereo audio stream by
2871 dropping the extra channels:
2873 pan="stereo| c0=FL | c1=FR"
2876 Given the same source, you can also switch front left and front right channels
2877 and keep the input channel layout:
2879 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
2882 If the input is a stereo audio stream, you can mute the front left channel (and
2883 still keep the stereo channel layout) with:
2888 Still with a stereo audio stream input, you can copy the right channel in both
2889 front left and right:
2891 pan="stereo| c0=FR | c1=FR"
2896 ReplayGain scanner filter. This filter takes an audio stream as an input and
2897 outputs it unchanged.
2898 At end of filtering it displays @code{track_gain} and @code{track_peak}.
2902 Convert the audio sample format, sample rate and channel layout. It is
2903 not meant to be used directly.
2906 Apply time-stretching and pitch-shifting with librubberband.
2908 The filter accepts the following options:
2912 Set tempo scale factor.
2915 Set pitch scale factor.
2918 Set transients detector.
2919 Possible values are:
2928 Possible values are:
2937 Possible values are:
2944 Set processing window size.
2945 Possible values are:
2954 Possible values are:
2961 Enable formant preservation when shift pitching.
2962 Possible values are:
2970 Possible values are:
2979 Possible values are:
2986 @section sidechaincompress
2988 This filter acts like normal compressor but has the ability to compress
2989 detected signal using second input signal.
2990 It needs two input streams and returns one output stream.
2991 First input stream will be processed depending on second stream signal.
2992 The filtered signal then can be filtered with other filters in later stages of
2993 processing. See @ref{pan} and @ref{amerge} filter.
2995 The filter accepts the following options:
2999 Set input gain. Default is 1. Range is between 0.015625 and 64.
3002 If a signal of second stream raises above this level it will affect the gain
3003 reduction of first stream.
3004 By default is 0.125. Range is between 0.00097563 and 1.
3007 Set a ratio about which the signal is reduced. 1:2 means that if the level
3008 raised 4dB above the threshold, it will be only 2dB above after the reduction.
3009 Default is 2. Range is between 1 and 20.
3012 Amount of milliseconds the signal has to rise above the threshold before gain
3013 reduction starts. Default is 20. Range is between 0.01 and 2000.
3016 Amount of milliseconds the signal has to fall below the threshold before
3017 reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
3020 Set the amount by how much signal will be amplified after processing.
3021 Default is 2. Range is from 1 and 64.
3024 Curve the sharp knee around the threshold to enter gain reduction more softly.
3025 Default is 2.82843. Range is between 1 and 8.
3028 Choose if the @code{average} level between all channels of side-chain stream
3029 or the louder(@code{maximum}) channel of side-chain stream affects the
3030 reduction. Default is @code{average}.
3033 Should the exact signal be taken in case of @code{peak} or an RMS one in case
3034 of @code{rms}. Default is @code{rms} which is mainly smoother.
3037 Set sidechain gain. Default is 1. Range is between 0.015625 and 64.
3040 How much to use compressed signal in output. Default is 1.
3041 Range is between 0 and 1.
3044 @subsection Examples
3048 Full ffmpeg example taking 2 audio inputs, 1st input to be compressed
3049 depending on the signal of 2nd input and later compressed signal to be
3050 merged with 2nd input:
3052 ffmpeg -i main.flac -i sidechain.flac -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress[compr];[compr][mix]amerge"
3056 @section sidechaingate
3058 A sidechain gate acts like a normal (wideband) gate but has the ability to
3059 filter the detected signal before sending it to the gain reduction stage.
3060 Normally a gate uses the full range signal to detect a level above the
3062 For example: If you cut all lower frequencies from your sidechain signal
3063 the gate will decrease the volume of your track only if not enough highs
3064 appear. With this technique you are able to reduce the resonation of a
3065 natural drum or remove "rumbling" of muted strokes from a heavily distorted
3067 It needs two input streams and returns one output stream.
3068 First input stream will be processed depending on second stream signal.
3070 The filter accepts the following options:
3074 Set input level before filtering.
3075 Default is 1. Allowed range is from 0.015625 to 64.
3078 Set the level of gain reduction when the signal is below the threshold.
3079 Default is 0.06125. Allowed range is from 0 to 1.
3082 If a signal rises above this level the gain reduction is released.
3083 Default is 0.125. Allowed range is from 0 to 1.
3086 Set a ratio about which the signal is reduced.
3087 Default is 2. Allowed range is from 1 to 9000.
3090 Amount of milliseconds the signal has to rise above the threshold before gain
3092 Default is 20 milliseconds. Allowed range is from 0.01 to 9000.
3095 Amount of milliseconds the signal has to fall below the threshold before the
3096 reduction is increased again. Default is 250 milliseconds.
3097 Allowed range is from 0.01 to 9000.
3100 Set amount of amplification of signal after processing.
3101 Default is 1. Allowed range is from 1 to 64.
3104 Curve the sharp knee around the threshold to enter gain reduction more softly.
3105 Default is 2.828427125. Allowed range is from 1 to 8.
3108 Choose if exact signal should be taken for detection or an RMS like one.
3109 Default is rms. Can be peak or rms.
3112 Choose if the average level between all channels or the louder channel affects
3114 Default is average. Can be average or maximum.
3117 Set sidechain gain. Default is 1. Range is from 0.015625 to 64.
3120 @section silencedetect
3122 Detect silence in an audio stream.
3124 This filter logs a message when it detects that the input audio volume is less
3125 or equal to a noise tolerance value for a duration greater or equal to the
3126 minimum detected noise duration.
3128 The printed times and duration are expressed in seconds.
3130 The filter accepts the following options:
3134 Set silence duration until notification (default is 2 seconds).
3137 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
3138 specified value) or amplitude ratio. Default is -60dB, or 0.001.
3141 @subsection Examples
3145 Detect 5 seconds of silence with -50dB noise tolerance:
3147 silencedetect=n=-50dB:d=5
3151 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
3152 tolerance in @file{silence.mp3}:
3154 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
3158 @section silenceremove
3160 Remove silence from the beginning, middle or end of the audio.
3162 The filter accepts the following options:
3166 This value is used to indicate if audio should be trimmed at beginning of
3167 the audio. A value of zero indicates no silence should be trimmed from the
3168 beginning. When specifying a non-zero value, it trims audio up until it
3169 finds non-silence. Normally, when trimming silence from beginning of audio
3170 the @var{start_periods} will be @code{1} but it can be increased to higher
3171 values to trim all audio up to specific count of non-silence periods.
3172 Default value is @code{0}.
3174 @item start_duration
3175 Specify the amount of time that non-silence must be detected before it stops
3176 trimming audio. By increasing the duration, bursts of noises can be treated
3177 as silence and trimmed off. Default value is @code{0}.
3179 @item start_threshold
3180 This indicates what sample value should be treated as silence. For digital
3181 audio, a value of @code{0} may be fine but for audio recorded from analog,
3182 you may wish to increase the value to account for background noise.
3183 Can be specified in dB (in case "dB" is appended to the specified value)
3184 or amplitude ratio. Default value is @code{0}.
3187 Set the count for trimming silence from the end of audio.
3188 To remove silence from the middle of a file, specify a @var{stop_periods}
3189 that is negative. This value is then treated as a positive value and is
3190 used to indicate the effect should restart processing as specified by
3191 @var{start_periods}, making it suitable for removing periods of silence
3192 in the middle of the audio.
3193 Default value is @code{0}.
3196 Specify a duration of silence that must exist before audio is not copied any
3197 more. By specifying a higher duration, silence that is wanted can be left in
3199 Default value is @code{0}.
3201 @item stop_threshold
3202 This is the same as @option{start_threshold} but for trimming silence from
3204 Can be specified in dB (in case "dB" is appended to the specified value)
3205 or amplitude ratio. Default value is @code{0}.
3208 This indicate that @var{stop_duration} length of audio should be left intact
3209 at the beginning of each period of silence.
3210 For example, if you want to remove long pauses between words but do not want
3211 to remove the pauses completely. Default value is @code{0}.
3214 Set how is silence detected. Can be @code{rms} or @code{peak}. Second is faster
3215 and works better with digital silence which is exactly 0.
3216 Default value is @code{rms}.
3219 Set ratio used to calculate size of window for detecting silence.
3220 Default value is @code{0.02}. Allowed range is from @code{0} to @code{10}.
3223 @subsection Examples
3227 The following example shows how this filter can be used to start a recording
3228 that does not contain the delay at the start which usually occurs between
3229 pressing the record button and the start of the performance:
3231 silenceremove=1:5:0.02
3235 Trim all silence encountered from begining to end where there is more than 1
3236 second of silence in audio:
3238 silenceremove=0:0:0:-1:1:-90dB
3244 SOFAlizer uses head-related transfer functions (HRTFs) to create virtual
3245 loudspeakers around the user for binaural listening via headphones (audio
3246 formats up to 9 channels supported).
3247 The HRTFs are stored in SOFA files (see @url{http://www.sofacoustics.org/} for a database).
3248 SOFAlizer is developed at the Acoustics Research Institute (ARI) of the
3249 Austrian Academy of Sciences.
3251 To enable compilation of this filter you need to configure FFmpeg with
3252 @code{--enable-netcdf}.
3254 The filter accepts the following options:
3258 Set the SOFA file used for rendering.
3261 Set gain applied to audio. Value is in dB. Default is 0.
3264 Set rotation of virtual loudspeakers in deg. Default is 0.
3267 Set elevation of virtual speakers in deg. Default is 0.
3270 Set distance in meters between loudspeakers and the listener with near-field
3271 HRTFs. Default is 1.
3274 Set processing type. Can be @var{time} or @var{freq}. @var{time} is
3275 processing audio in time domain which is slow.
3276 @var{freq} is processing audio in frequency domain which is fast.
3277 Default is @var{freq}.
3280 Set custom positions of virtual loudspeakers. Syntax for this option is:
3281 <CH> <AZIM> <ELEV>[|<CH> <AZIM> <ELEV>|...].
3282 Each virtual loudspeaker is described with short channel name following with
3283 azimuth and elevation in degreees.
3284 Each virtual loudspeaker description is separated by '|'.
3285 For example to override front left and front right channel positions use:
3286 'speakers=FL 45 15|FR 345 15'.
3287 Descriptions with unrecognised channel names are ignored.
3290 @subsection Examples
3294 Using ClubFritz6 sofa file:
3296 sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=1
3300 Using ClubFritz12 sofa file and bigger radius with small rotation:
3302 sofalizer=sofa=/path/to/ClubFritz12.sofa:type=freq:radius=2:rotation=5
3306 Similar as above but with custom speaker positions for front left, front right, rear left and rear right
3307 and also with custom gain:
3309 "sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=2:speakers=FL 45|FR 315|RL 135|RR 225:gain=28"
3313 @section stereotools
3315 This filter has some handy utilities to manage stereo signals, for converting
3316 M/S stereo recordings to L/R signal while having control over the parameters
3317 or spreading the stereo image of master track.
3319 The filter accepts the following options:
3323 Set input level before filtering for both channels. Defaults is 1.
3324 Allowed range is from 0.015625 to 64.
3327 Set output level after filtering for both channels. Defaults is 1.
3328 Allowed range is from 0.015625 to 64.
3331 Set input balance between both channels. Default is 0.
3332 Allowed range is from -1 to 1.
3335 Set output balance between both channels. Default is 0.
3336 Allowed range is from -1 to 1.
3339 Enable softclipping. Results in analog distortion instead of harsh digital 0dB
3340 clipping. Disabled by default.
3343 Mute the left channel. Disabled by default.
3346 Mute the right channel. Disabled by default.
3349 Change the phase of the left channel. Disabled by default.
3352 Change the phase of the right channel. Disabled by default.
3355 Set stereo mode. Available values are:
3359 Left/Right to Left/Right, this is default.
3362 Left/Right to Mid/Side.
3365 Mid/Side to Left/Right.
3368 Left/Right to Left/Left.
3371 Left/Right to Right/Right.
3374 Left/Right to Left + Right.
3377 Left/Right to Right/Left.
3381 Set level of side signal. Default is 1.
3382 Allowed range is from 0.015625 to 64.
3385 Set balance of side signal. Default is 0.
3386 Allowed range is from -1 to 1.
3389 Set level of the middle signal. Default is 1.
3390 Allowed range is from 0.015625 to 64.
3393 Set middle signal pan. Default is 0. Allowed range is from -1 to 1.
3396 Set stereo base between mono and inversed channels. Default is 0.
3397 Allowed range is from -1 to 1.
3400 Set delay in milliseconds how much to delay left from right channel and
3401 vice versa. Default is 0. Allowed range is from -20 to 20.
3404 Set S/C level. Default is 1. Allowed range is from 1 to 100.
3407 Set the stereo phase in degrees. Default is 0. Allowed range is from 0 to 360.
3410 @subsection Examples
3414 Apply karaoke like effect:
3416 stereotools=mlev=0.015625
3420 Convert M/S signal to L/R:
3422 "stereotools=mode=ms>lr"
3426 @section stereowiden
3428 This filter enhance the stereo effect by suppressing signal common to both
3429 channels and by delaying the signal of left into right and vice versa,
3430 thereby widening the stereo effect.
3432 The filter accepts the following options:
3436 Time in milliseconds of the delay of left signal into right and vice versa.
3437 Default is 20 milliseconds.
3440 Amount of gain in delayed signal into right and vice versa. Gives a delay
3441 effect of left signal in right output and vice versa which gives widening
3442 effect. Default is 0.3.
3445 Cross feed of left into right with inverted phase. This helps in suppressing
3446 the mono. If the value is 1 it will cancel all the signal common to both
3447 channels. Default is 0.3.
3450 Set level of input signal of original channel. Default is 0.8.
3455 Use the NVIDIA Performance Primitives (libnpp) to perform scaling and/or pixel
3456 format conversion on CUDA video frames. Setting the output width and height
3457 works in the same way as for the @var{scale} filter.
3459 The following additional options are accepted:
3462 The pixel format of the output CUDA frames. If set to the string "same" (the
3463 default), the input format will be kept. Note that automatic format negotiation
3464 and conversion is not yet supported for hardware frames
3467 The interpolation algorithm used for resizing. One of the following:
3474 @item cubic2p_bspline
3475 2-parameter cubic (B=1, C=0)
3477 @item cubic2p_catmullrom
3478 2-parameter cubic (B=0, C=1/2)
3480 @item cubic2p_b05c03
3481 2-parameter cubic (B=1/2, C=3/10)
3492 Select frames to pass in output.
3496 Boost or cut treble (upper) frequencies of the audio using a two-pole
3497 shelving filter with a response similar to that of a standard
3498 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
3500 The filter accepts the following options:
3504 Give the gain at whichever is the lower of ~22 kHz and the
3505 Nyquist frequency. Its useful range is about -20 (for a large cut)
3506 to +20 (for a large boost). Beware of clipping when using a positive gain.
3509 Set the filter's central frequency and so can be used
3510 to extend or reduce the frequency range to be boosted or cut.
3511 The default value is @code{3000} Hz.
3514 Set method to specify band-width of filter.
3527 Determine how steep is the filter's shelf transition.
3532 Sinusoidal amplitude modulation.
3534 The filter accepts the following options:
3538 Modulation frequency in Hertz. Modulation frequencies in the subharmonic range
3539 (20 Hz or lower) will result in a tremolo effect.
3540 This filter may also be used as a ring modulator by specifying
3541 a modulation frequency higher than 20 Hz.
3542 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
3545 Depth of modulation as a percentage. Range is 0.0 - 1.0.
3546 Default value is 0.5.
3551 Sinusoidal phase modulation.
3553 The filter accepts the following options:
3557 Modulation frequency in Hertz.
3558 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
3561 Depth of modulation as a percentage. Range is 0.0 - 1.0.
3562 Default value is 0.5.
3567 Adjust the input audio volume.
3569 It accepts the following parameters:
3573 Set audio volume expression.
3575 Output values are clipped to the maximum value.
3577 The output audio volume is given by the relation:
3579 @var{output_volume} = @var{volume} * @var{input_volume}
3582 The default value for @var{volume} is "1.0".
3585 This parameter represents the mathematical precision.
3587 It determines which input sample formats will be allowed, which affects the
3588 precision of the volume scaling.
3592 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
3594 32-bit floating-point; this limits input sample format to FLT. (default)
3596 64-bit floating-point; this limits input sample format to DBL.
3600 Choose the behaviour on encountering ReplayGain side data in input frames.
3604 Remove ReplayGain side data, ignoring its contents (the default).
3607 Ignore ReplayGain side data, but leave it in the frame.
3610 Prefer the track gain, if present.
3613 Prefer the album gain, if present.
3616 @item replaygain_preamp
3617 Pre-amplification gain in dB to apply to the selected replaygain gain.
3619 Default value for @var{replaygain_preamp} is 0.0.
3622 Set when the volume expression is evaluated.
3624 It accepts the following values:
3627 only evaluate expression once during the filter initialization, or
3628 when the @samp{volume} command is sent
3631 evaluate expression for each incoming frame
3634 Default value is @samp{once}.
3637 The volume expression can contain the following parameters.
3641 frame number (starting at zero)
3644 @item nb_consumed_samples
3645 number of samples consumed by the filter
3647 number of samples in the current frame
3649 original frame position in the file
3655 PTS at start of stream
3657 time at start of stream
3663 last set volume value
3666 Note that when @option{eval} is set to @samp{once} only the
3667 @var{sample_rate} and @var{tb} variables are available, all other
3668 variables will evaluate to NAN.
3670 @subsection Commands
3672 This filter supports the following commands:
3675 Modify the volume expression.
3676 The command accepts the same syntax of the corresponding option.
3678 If the specified expression is not valid, it is kept at its current
3680 @item replaygain_noclip
3681 Prevent clipping by limiting the gain applied.
3683 Default value for @var{replaygain_noclip} is 1.
3687 @subsection Examples
3691 Halve the input audio volume:
3695 volume=volume=-6.0206dB
3698 In all the above example the named key for @option{volume} can be
3699 omitted, for example like in:
3705 Increase input audio power by 6 decibels using fixed-point precision:
3707 volume=volume=6dB:precision=fixed
3711 Fade volume after time 10 with an annihilation period of 5 seconds:
3713 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
3717 @section volumedetect
3719 Detect the volume of the input video.
3721 The filter has no parameters. The input is not modified. Statistics about
3722 the volume will be printed in the log when the input stream end is reached.
3724 In particular it will show the mean volume (root mean square), maximum
3725 volume (on a per-sample basis), and the beginning of a histogram of the
3726 registered volume values (from the maximum value to a cumulated 1/1000 of
3729 All volumes are in decibels relative to the maximum PCM value.
3731 @subsection Examples
3733 Here is an excerpt of the output:
3735 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
3736 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
3737 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
3738 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
3739 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
3740 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
3741 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
3742 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
3743 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
3749 The mean square energy is approximately -27 dB, or 10^-2.7.
3751 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
3753 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
3756 In other words, raising the volume by +4 dB does not cause any clipping,
3757 raising it by +5 dB causes clipping for 6 samples, etc.
3759 @c man end AUDIO FILTERS
3761 @chapter Audio Sources
3762 @c man begin AUDIO SOURCES
3764 Below is a description of the currently available audio sources.
3768 Buffer audio frames, and make them available to the filter chain.
3770 This source is mainly intended for a programmatic use, in particular
3771 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
3773 It accepts the following parameters:
3777 The timebase which will be used for timestamps of submitted frames. It must be
3778 either a floating-point number or in @var{numerator}/@var{denominator} form.
3781 The sample rate of the incoming audio buffers.
3784 The sample format of the incoming audio buffers.
3785 Either a sample format name or its corresponding integer representation from
3786 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
3788 @item channel_layout
3789 The channel layout of the incoming audio buffers.
3790 Either a channel layout name from channel_layout_map in
3791 @file{libavutil/channel_layout.c} or its corresponding integer representation
3792 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
3795 The number of channels of the incoming audio buffers.
3796 If both @var{channels} and @var{channel_layout} are specified, then they
3801 @subsection Examples
3804 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
3807 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
3808 Since the sample format with name "s16p" corresponds to the number
3809 6 and the "stereo" channel layout corresponds to the value 0x3, this is
3812 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
3817 Generate an audio signal specified by an expression.
3819 This source accepts in input one or more expressions (one for each
3820 channel), which are evaluated and used to generate a corresponding
3823 This source accepts the following options:
3827 Set the '|'-separated expressions list for each separate channel. In case the
3828 @option{channel_layout} option is not specified, the selected channel layout
3829 depends on the number of provided expressions. Otherwise the last
3830 specified expression is applied to the remaining output channels.
3832 @item channel_layout, c
3833 Set the channel layout. The number of channels in the specified layout
3834 must be equal to the number of specified expressions.
3837 Set the minimum duration of the sourced audio. See
3838 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
3839 for the accepted syntax.
3840 Note that the resulting duration may be greater than the specified
3841 duration, as the generated audio is always cut at the end of a
3844 If not specified, or the expressed duration is negative, the audio is
3845 supposed to be generated forever.
3848 Set the number of samples per channel per each output frame,
3851 @item sample_rate, s
3852 Specify the sample rate, default to 44100.
3855 Each expression in @var{exprs} can contain the following constants:
3859 number of the evaluated sample, starting from 0
3862 time of the evaluated sample expressed in seconds, starting from 0
3869 @subsection Examples
3879 Generate a sin signal with frequency of 440 Hz, set sample rate to
3882 aevalsrc="sin(440*2*PI*t):s=8000"
3886 Generate a two channels signal, specify the channel layout (Front
3887 Center + Back Center) explicitly:
3889 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
3893 Generate white noise:
3895 aevalsrc="-2+random(0)"
3899 Generate an amplitude modulated signal:
3901 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
3905 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
3907 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
3914 The null audio source, return unprocessed audio frames. It is mainly useful
3915 as a template and to be employed in analysis / debugging tools, or as
3916 the source for filters which ignore the input data (for example the sox
3919 This source accepts the following options:
3923 @item channel_layout, cl
3925 Specifies the channel layout, and can be either an integer or a string
3926 representing a channel layout. The default value of @var{channel_layout}
3929 Check the channel_layout_map definition in
3930 @file{libavutil/channel_layout.c} for the mapping between strings and
3931 channel layout values.
3933 @item sample_rate, r
3934 Specifies the sample rate, and defaults to 44100.
3937 Set the number of samples per requested frames.
3941 @subsection Examples
3945 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
3947 anullsrc=r=48000:cl=4
3951 Do the same operation with a more obvious syntax:
3953 anullsrc=r=48000:cl=mono
3957 All the parameters need to be explicitly defined.
3961 Synthesize a voice utterance using the libflite library.
3963 To enable compilation of this filter you need to configure FFmpeg with
3964 @code{--enable-libflite}.
3966 Note that the flite library is not thread-safe.
3968 The filter accepts the following options:
3973 If set to 1, list the names of the available voices and exit
3974 immediately. Default value is 0.
3977 Set the maximum number of samples per frame. Default value is 512.
3980 Set the filename containing the text to speak.
3983 Set the text to speak.
3986 Set the voice to use for the speech synthesis. Default value is
3987 @code{kal}. See also the @var{list_voices} option.
3990 @subsection Examples
3994 Read from file @file{speech.txt}, and synthesize the text using the
3995 standard flite voice:
3997 flite=textfile=speech.txt
4001 Read the specified text selecting the @code{slt} voice:
4003 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
4007 Input text to ffmpeg:
4009 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
4013 Make @file{ffplay} speak the specified text, using @code{flite} and
4014 the @code{lavfi} device:
4016 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
4020 For more information about libflite, check:
4021 @url{http://www.speech.cs.cmu.edu/flite/}
4025 Generate a noise audio signal.
4027 The filter accepts the following options:
4030 @item sample_rate, r
4031 Specify the sample rate. Default value is 48000 Hz.
4034 Specify the amplitude (0.0 - 1.0) of the generated audio stream. Default value
4038 Specify the duration of the generated audio stream. Not specifying this option
4039 results in noise with an infinite length.
4041 @item color, colour, c
4042 Specify the color of noise. Available noise colors are white, pink, and brown.
4043 Default color is white.
4046 Specify a value used to seed the PRNG.
4049 Set the number of samples per each output frame, default is 1024.
4052 @subsection Examples
4057 Generate 60 seconds of pink noise, with a 44.1 kHz sampling rate and an amplitude of 0.5:
4059 anoisesrc=d=60:c=pink:r=44100:a=0.5
4065 Generate an audio signal made of a sine wave with amplitude 1/8.
4067 The audio signal is bit-exact.
4069 The filter accepts the following options:
4074 Set the carrier frequency. Default is 440 Hz.
4076 @item beep_factor, b
4077 Enable a periodic beep every second with frequency @var{beep_factor} times
4078 the carrier frequency. Default is 0, meaning the beep is disabled.
4080 @item sample_rate, r
4081 Specify the sample rate, default is 44100.
4084 Specify the duration of the generated audio stream.
4086 @item samples_per_frame
4087 Set the number of samples per output frame.
4089 The expression can contain the following constants:
4093 The (sequential) number of the output audio frame, starting from 0.
4096 The PTS (Presentation TimeStamp) of the output audio frame,
4097 expressed in @var{TB} units.
4100 The PTS of the output audio frame, expressed in seconds.
4103 The timebase of the output audio frames.
4106 Default is @code{1024}.
4109 @subsection Examples
4114 Generate a simple 440 Hz sine wave:
4120 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
4124 sine=frequency=220:beep_factor=4:duration=5
4128 Generate a 1 kHz sine wave following @code{1602,1601,1602,1601,1602} NTSC
4131 sine=1000:samples_per_frame='st(0,mod(n,5)); 1602-not(not(eq(ld(0),1)+eq(ld(0),3)))'
4135 @c man end AUDIO SOURCES
4137 @chapter Audio Sinks
4138 @c man begin AUDIO SINKS
4140 Below is a description of the currently available audio sinks.
4142 @section abuffersink
4144 Buffer audio frames, and make them available to the end of filter chain.
4146 This sink is mainly intended for programmatic use, in particular
4147 through the interface defined in @file{libavfilter/buffersink.h}
4148 or the options system.
4150 It accepts a pointer to an AVABufferSinkContext structure, which
4151 defines the incoming buffers' formats, to be passed as the opaque
4152 parameter to @code{avfilter_init_filter} for initialization.
4155 Null audio sink; do absolutely nothing with the input audio. It is
4156 mainly useful as a template and for use in analysis / debugging
4159 @c man end AUDIO SINKS
4161 @chapter Video Filters
4162 @c man begin VIDEO FILTERS
4164 When you configure your FFmpeg build, you can disable any of the
4165 existing filters using @code{--disable-filters}.
4166 The configure output will show the video filters included in your
4169 Below is a description of the currently available video filters.
4171 @section alphaextract
4173 Extract the alpha component from the input as a grayscale video. This
4174 is especially useful with the @var{alphamerge} filter.
4178 Add or replace the alpha component of the primary input with the
4179 grayscale value of a second input. This is intended for use with
4180 @var{alphaextract} to allow the transmission or storage of frame
4181 sequences that have alpha in a format that doesn't support an alpha
4184 For example, to reconstruct full frames from a normal YUV-encoded video
4185 and a separate video created with @var{alphaextract}, you might use:
4187 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
4190 Since this filter is designed for reconstruction, it operates on frame
4191 sequences without considering timestamps, and terminates when either
4192 input reaches end of stream. This will cause problems if your encoding
4193 pipeline drops frames. If you're trying to apply an image as an
4194 overlay to a video stream, consider the @var{overlay} filter instead.
4198 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
4199 and libavformat to work. On the other hand, it is limited to ASS (Advanced
4200 Substation Alpha) subtitles files.
4202 This filter accepts the following option in addition to the common options from
4203 the @ref{subtitles} filter:
4207 Set the shaping engine
4209 Available values are:
4212 The default libass shaping engine, which is the best available.
4214 Fast, font-agnostic shaper that can do only substitutions
4216 Slower shaper using OpenType for substitutions and positioning
4219 The default is @code{auto}.
4223 Apply an Adaptive Temporal Averaging Denoiser to the video input.
4225 The filter accepts the following options:
4229 Set threshold A for 1st plane. Default is 0.02.
4230 Valid range is 0 to 0.3.
4233 Set threshold B for 1st plane. Default is 0.04.
4234 Valid range is 0 to 5.
4237 Set threshold A for 2nd plane. Default is 0.02.
4238 Valid range is 0 to 0.3.
4241 Set threshold B for 2nd plane. Default is 0.04.
4242 Valid range is 0 to 5.
4245 Set threshold A for 3rd plane. Default is 0.02.
4246 Valid range is 0 to 0.3.
4249 Set threshold B for 3rd plane. Default is 0.04.
4250 Valid range is 0 to 5.
4252 Threshold A is designed to react on abrupt changes in the input signal and
4253 threshold B is designed to react on continuous changes in the input signal.
4256 Set number of frames filter will use for averaging. Default is 33. Must be odd
4257 number in range [5, 129].
4262 Compute the bounding box for the non-black pixels in the input frame
4265 This filter computes the bounding box containing all the pixels with a
4266 luminance value greater than the minimum allowed value.
4267 The parameters describing the bounding box are printed on the filter
4270 The filter accepts the following option:
4274 Set the minimal luminance value. Default is @code{16}.
4277 @section blackdetect
4279 Detect video intervals that are (almost) completely black. Can be
4280 useful to detect chapter transitions, commercials, or invalid
4281 recordings. Output lines contains the time for the start, end and
4282 duration of the detected black interval expressed in seconds.
4284 In order to display the output lines, you need to set the loglevel at
4285 least to the AV_LOG_INFO value.
4287 The filter accepts the following options:
4290 @item black_min_duration, d
4291 Set the minimum detected black duration expressed in seconds. It must
4292 be a non-negative floating point number.
4294 Default value is 2.0.
4296 @item picture_black_ratio_th, pic_th
4297 Set the threshold for considering a picture "black".
4298 Express the minimum value for the ratio:
4300 @var{nb_black_pixels} / @var{nb_pixels}
4303 for which a picture is considered black.
4304 Default value is 0.98.
4306 @item pixel_black_th, pix_th
4307 Set the threshold for considering a pixel "black".
4309 The threshold expresses the maximum pixel luminance value for which a
4310 pixel is considered "black". The provided value is scaled according to
4311 the following equation:
4313 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
4316 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
4317 the input video format, the range is [0-255] for YUV full-range
4318 formats and [16-235] for YUV non full-range formats.
4320 Default value is 0.10.
4323 The following example sets the maximum pixel threshold to the minimum
4324 value, and detects only black intervals of 2 or more seconds:
4326 blackdetect=d=2:pix_th=0.00
4331 Detect frames that are (almost) completely black. Can be useful to
4332 detect chapter transitions or commercials. Output lines consist of
4333 the frame number of the detected frame, the percentage of blackness,
4334 the position in the file if known or -1 and the timestamp in seconds.
4336 In order to display the output lines, you need to set the loglevel at
4337 least to the AV_LOG_INFO value.
4339 It accepts the following parameters:
4344 The percentage of the pixels that have to be below the threshold; it defaults to
4347 @item threshold, thresh
4348 The threshold below which a pixel value is considered black; it defaults to
4353 @section blend, tblend
4355 Blend two video frames into each other.
4357 The @code{blend} filter takes two input streams and outputs one
4358 stream, the first input is the "top" layer and second input is
4359 "bottom" layer. Output terminates when shortest input terminates.
4361 The @code{tblend} (time blend) filter takes two consecutive frames
4362 from one single stream, and outputs the result obtained by blending
4363 the new frame on top of the old frame.
4365 A description of the accepted options follows.
4373 Set blend mode for specific pixel component or all pixel components in case
4374 of @var{all_mode}. Default value is @code{normal}.
4376 Available values for component modes are:
4417 Set blend opacity for specific pixel component or all pixel components in case
4418 of @var{all_opacity}. Only used in combination with pixel component blend modes.
4425 Set blend expression for specific pixel component or all pixel components in case
4426 of @var{all_expr}. Note that related mode options will be ignored if those are set.
4428 The expressions can use the following variables:
4432 The sequential number of the filtered frame, starting from @code{0}.
4436 the coordinates of the current sample
4440 the width and height of currently filtered plane
4444 Width and height scale depending on the currently filtered plane. It is the
4445 ratio between the corresponding luma plane number of pixels and the current
4446 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4447 @code{0.5,0.5} for chroma planes.
4450 Time of the current frame, expressed in seconds.
4453 Value of pixel component at current location for first video frame (top layer).
4456 Value of pixel component at current location for second video frame (bottom layer).
4460 Force termination when the shortest input terminates. Default is
4461 @code{0}. This option is only defined for the @code{blend} filter.
4464 Continue applying the last bottom frame after the end of the stream. A value of
4465 @code{0} disable the filter after the last frame of the bottom layer is reached.
4466 Default is @code{1}. This option is only defined for the @code{blend} filter.
4469 @subsection Examples
4473 Apply transition from bottom layer to top layer in first 10 seconds:
4475 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
4479 Apply 1x1 checkerboard effect:
4481 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
4485 Apply uncover left effect:
4487 blend=all_expr='if(gte(N*SW+X,W),A,B)'
4491 Apply uncover down effect:
4493 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
4497 Apply uncover up-left effect:
4499 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
4503 Split diagonally video and shows top and bottom layer on each side:
4505 blend=all_expr=if(gt(X,Y*(W/H)),A,B)
4509 Display differences between the current and the previous frame:
4511 tblend=all_mode=difference128
4517 Deinterlace the input video ("bwdif" stands for "Bob Weaver
4518 Deinterlacing Filter").
4520 Motion adaptive deinterlacing based on yadif with the use of w3fdif and cubic
4521 interpolation algorithms.
4522 It accepts the following parameters:
4526 The interlacing mode to adopt. It accepts one of the following values:
4530 Output one frame for each frame.
4532 Output one frame for each field.
4535 The default value is @code{send_field}.
4538 The picture field parity assumed for the input interlaced video. It accepts one
4539 of the following values:
4543 Assume the top field is first.
4545 Assume the bottom field is first.
4547 Enable automatic detection of field parity.
4550 The default value is @code{auto}.
4551 If the interlacing is unknown or the decoder does not export this information,
4552 top field first will be assumed.
4555 Specify which frames to deinterlace. Accept one of the following
4560 Deinterlace all frames.
4562 Only deinterlace frames marked as interlaced.
4565 The default value is @code{all}.
4570 Apply a boxblur algorithm to the input video.
4572 It accepts the following parameters:
4576 @item luma_radius, lr
4577 @item luma_power, lp
4578 @item chroma_radius, cr
4579 @item chroma_power, cp
4580 @item alpha_radius, ar
4581 @item alpha_power, ap
4585 A description of the accepted options follows.
4588 @item luma_radius, lr
4589 @item chroma_radius, cr
4590 @item alpha_radius, ar
4591 Set an expression for the box radius in pixels used for blurring the
4592 corresponding input plane.
4594 The radius value must be a non-negative number, and must not be
4595 greater than the value of the expression @code{min(w,h)/2} for the
4596 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
4599 Default value for @option{luma_radius} is "2". If not specified,
4600 @option{chroma_radius} and @option{alpha_radius} default to the
4601 corresponding value set for @option{luma_radius}.
4603 The expressions can contain the following constants:
4607 The input width and height in pixels.
4611 The input chroma image width and height in pixels.
4615 The horizontal and vertical chroma subsample values. For example, for the
4616 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
4619 @item luma_power, lp
4620 @item chroma_power, cp
4621 @item alpha_power, ap
4622 Specify how many times the boxblur filter is applied to the
4623 corresponding plane.
4625 Default value for @option{luma_power} is 2. If not specified,
4626 @option{chroma_power} and @option{alpha_power} default to the
4627 corresponding value set for @option{luma_power}.
4629 A value of 0 will disable the effect.
4632 @subsection Examples
4636 Apply a boxblur filter with the luma, chroma, and alpha radii
4639 boxblur=luma_radius=2:luma_power=1
4644 Set the luma radius to 2, and alpha and chroma radius to 0:
4646 boxblur=2:1:cr=0:ar=0
4650 Set the luma and chroma radii to a fraction of the video dimension:
4652 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
4657 YUV colorspace color/chroma keying.
4659 The filter accepts the following options:
4663 The color which will be replaced with transparency.
4666 Similarity percentage with the key color.
4668 0.01 matches only the exact key color, while 1.0 matches everything.
4673 0.0 makes pixels either fully transparent, or not transparent at all.
4675 Higher values result in semi-transparent pixels, with a higher transparency
4676 the more similar the pixels color is to the key color.
4679 Signals that the color passed is already in YUV instead of RGB.
4681 Litteral colors like "green" or "red" don't make sense with this enabled anymore.
4682 This can be used to pass exact YUV values as hexadecimal numbers.
4685 @subsection Examples
4689 Make every green pixel in the input image transparent:
4691 ffmpeg -i input.png -vf chromakey=green out.png
4695 Overlay a greenscreen-video on top of a static black background.
4697 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
4703 Display CIE color diagram with pixels overlaid onto it.
4705 The filter acccepts the following options:
4720 @item uhdtv, rec2020
4733 Set what gamuts to draw.
4735 See @code{system} option for avaiable values.
4738 Set ciescope size, by default set to 512.
4741 Set intensity used to map input pixel values to CIE diagram.
4744 Set contrast used to draw tongue colors that are out of active color system gamut.
4747 Correct gamma displayed on scope, by default enabled.
4750 Show white point on CIE diagram, by default disabled.
4753 Set input gamma. Used only with XYZ input color space.
4758 Visualize information exported by some codecs.
4760 Some codecs can export information through frames using side-data or other
4761 means. For example, some MPEG based codecs export motion vectors through the
4762 @var{export_mvs} flag in the codec @option{flags2} option.
4764 The filter accepts the following option:
4768 Set motion vectors to visualize.
4770 Available flags for @var{mv} are:
4774 forward predicted MVs of P-frames
4776 forward predicted MVs of B-frames
4778 backward predicted MVs of B-frames
4782 Display quantization parameters using the chroma planes
4785 @subsection Examples
4789 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
4791 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
4795 @section colorbalance
4796 Modify intensity of primary colors (red, green and blue) of input frames.
4798 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
4799 regions for the red-cyan, green-magenta or blue-yellow balance.
4801 A positive adjustment value shifts the balance towards the primary color, a negative
4802 value towards the complementary color.
4804 The filter accepts the following options:
4810 Adjust red, green and blue shadows (darkest pixels).
4815 Adjust red, green and blue midtones (medium pixels).
4820 Adjust red, green and blue highlights (brightest pixels).
4822 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
4825 @subsection Examples
4829 Add red color cast to shadows:
4836 RGB colorspace color keying.
4838 The filter accepts the following options:
4842 The color which will be replaced with transparency.
4845 Similarity percentage with the key color.
4847 0.01 matches only the exact key color, while 1.0 matches everything.
4852 0.0 makes pixels either fully transparent, or not transparent at all.
4854 Higher values result in semi-transparent pixels, with a higher transparency
4855 the more similar the pixels color is to the key color.
4858 @subsection Examples
4862 Make every green pixel in the input image transparent:
4864 ffmpeg -i input.png -vf colorkey=green out.png
4868 Overlay a greenscreen-video on top of a static background image.
4870 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
4874 @section colorlevels
4876 Adjust video input frames using levels.
4878 The filter accepts the following options:
4885 Adjust red, green, blue and alpha input black point.
4886 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
4892 Adjust red, green, blue and alpha input white point.
4893 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
4895 Input levels are used to lighten highlights (bright tones), darken shadows
4896 (dark tones), change the balance of bright and dark tones.
4902 Adjust red, green, blue and alpha output black point.
4903 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
4909 Adjust red, green, blue and alpha output white point.
4910 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
4912 Output levels allows manual selection of a constrained output level range.
4915 @subsection Examples
4919 Make video output darker:
4921 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
4927 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
4931 Make video output lighter:
4933 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
4937 Increase brightness:
4939 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
4943 @section colorchannelmixer
4945 Adjust video input frames by re-mixing color channels.
4947 This filter modifies a color channel by adding the values associated to
4948 the other channels of the same pixels. For example if the value to
4949 modify is red, the output value will be:
4951 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
4954 The filter accepts the following options:
4961 Adjust contribution of input red, green, blue and alpha channels for output red channel.
4962 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
4968 Adjust contribution of input red, green, blue and alpha channels for output green channel.
4969 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
4975 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
4976 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
4982 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
4983 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
4985 Allowed ranges for options are @code{[-2.0, 2.0]}.
4988 @subsection Examples
4992 Convert source to grayscale:
4994 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
4997 Simulate sepia tones:
4999 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
5003 @section colormatrix
5005 Convert color matrix.
5007 The filter accepts the following options:
5012 Specify the source and destination color matrix. Both values must be
5015 The accepted values are:
5031 For example to convert from BT.601 to SMPTE-240M, use the command:
5033 colormatrix=bt601:smpte240m
5038 Convert colorspace, transfer characteristics or color primaries.
5040 The filter accepts the following options:
5044 Specify all color properties at once.
5046 The accepted values are:
5075 Specify output colorspace.
5077 The accepted values are:
5086 BT.470BG or BT.601-6 625
5089 SMPTE-170M or BT.601-6 525
5095 BT.2020 with non-constant luminance
5100 Specify output transfer characteristics.
5102 The accepted values are:
5108 Constant gamma of 2.2
5111 Constant gamma of 2.8
5114 SMPTE-170M, BT.601-6 625 or BT.601-6 525
5120 BT.2020 for 10-bits content
5123 BT.2020 for 12-bits content
5128 Specify output color primaries.
5130 The accepted values are:
5139 BT.470BG or BT.601-6 625
5142 SMPTE-170M or BT.601-6 525
5153 Specify output color range.
5155 The accepted values are:
5158 MPEG (restricted) range
5166 Specify output color format.
5168 The accepted values are:
5171 YUV 4:2:0 planar 8-bits
5174 YUV 4:2:0 planar 10-bits
5177 YUV 4:2:0 planar 12-bits
5180 YUV 4:2:2 planar 8-bits
5183 YUV 4:2:2 planar 10-bits
5186 YUV 4:2:2 planar 12-bits
5189 YUV 4:4:4 planar 8-bits
5192 YUV 4:4:4 planar 10-bits
5195 YUV 4:4:4 planar 12-bits
5200 Do a fast conversion, which skips gamma/primary correction. This will take
5201 significantly less CPU, but will be mathematically incorrect. To get output
5202 compatible with that produced by the colormatrix filter, use fast=1.
5205 Specify dithering mode.
5207 The accepted values are:
5213 Floyd-Steinberg dithering
5217 Whitepoint adaptation mode.
5219 The accepted values are:
5222 Bradford whitepoint adaptation
5225 von Kries whitepoint adaptation
5228 identity whitepoint adaptation (i.e. no whitepoint adaptation)
5233 The filter converts the transfer characteristics, color space and color
5234 primaries to the specified user values. The output value, if not specified,
5235 is set to a default value based on the "all" property. If that property is
5236 also not specified, the filter will log an error. The output color range and
5237 format default to the same value as the input color range and format. The
5238 input transfer characteristics, color space, color primaries and color range
5239 should be set on the input data. If any of these are missing, the filter will
5240 log an error and no conversion will take place.
5242 For example to convert the input to SMPTE-240M, use the command:
5244 colorspace=smpte240m
5247 @section convolution
5249 Apply convolution 3x3 or 5x5 filter.
5251 The filter accepts the following options:
5258 Set matrix for each plane.
5259 Matrix is sequence of 9 or 25 signed integers.
5265 Set multiplier for calculated value for each plane.
5271 Set bias for each plane. This value is added to the result of the multiplication.
5272 Useful for making the overall image brighter or darker. Default is 0.0.
5275 @subsection Examples
5281 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"
5287 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"
5293 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"
5299 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"
5305 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"
5311 Copy the input source unchanged to the output. This is mainly useful for
5316 Video filtering on GPU using Apple's CoreImage API on OSX.
5318 Hardware acceleration is based on an OpenGL context. Usually, this means it is
5319 processed by video hardware. However, software-based OpenGL implementations
5320 exist which means there is no guarantee for hardware processing. It depends on
5323 There are many filters and image generators provided by Apple that come with a
5324 large variety of options. The filter has to be referenced by its name along
5327 The coreimage filter accepts the following options:
5330 List all available filters and generators along with all their respective
5331 options as well as possible minimum and maximum values along with the default
5338 Specify all filters by their respective name and options.
5339 Use @var{list_filters} to determine all valid filter names and options.
5340 Numerical options are specified by a float value and are automatically clamped
5341 to their respective value range. Vector and color options have to be specified
5342 by a list of space separated float values. Character escaping has to be done.
5343 A special option name @code{default} is available to use default options for a
5346 It is required to specify either @code{default} or at least one of the filter options.
5347 All omitted options are used with their default values.
5348 The syntax of the filter string is as follows:
5350 filter=<NAME>@@<OPTION>=<VALUE>[@@<OPTION>=<VALUE>][@@...][#<NAME>@@<OPTION>=<VALUE>[@@<OPTION>=<VALUE>][@@...]][#...]
5354 Specify a rectangle where the output of the filter chain is copied into the
5355 input image. It is given by a list of space separated float values:
5357 output_rect=x\ y\ width\ height
5359 If not given, the output rectangle equals the dimensions of the input image.
5360 The output rectangle is automatically cropped at the borders of the input
5361 image. Negative values are valid for each component.
5363 output_rect=25\ 25\ 100\ 100
5367 Several filters can be chained for successive processing without GPU-HOST
5368 transfers allowing for fast processing of complex filter chains.
5369 Currently, only filters with zero (generators) or exactly one (filters) input
5370 image and one output image are supported. Also, transition filters are not yet
5373 Some filters generate output images with additional padding depending on the
5374 respective filter kernel. The padding is automatically removed to ensure the
5375 filter output has the same size as the input image.
5377 For image generators, the size of the output image is determined by the
5378 previous output image of the filter chain or the input image of the whole
5379 filterchain, respectively. The generators do not use the pixel information of
5380 this image to generate their output. However, the generated output is
5381 blended onto this image, resulting in partial or complete coverage of the
5384 The @ref{coreimagesrc} video source can be used for generating input images
5385 which are directly fed into the filter chain. By using it, providing input
5386 images by another video source or an input video is not required.
5388 @subsection Examples
5393 List all filters available:
5395 coreimage=list_filters=true
5399 Use the CIBoxBlur filter with default options to blur an image:
5401 coreimage=filter=CIBoxBlur@@default
5405 Use a filter chain with CISepiaTone at default values and CIVignetteEffect with
5406 its center at 100x100 and a radius of 50 pixels:
5408 coreimage=filter=CIBoxBlur@@default#CIVignetteEffect@@inputCenter=100\ 100@@inputRadius=50
5412 Use nullsrc and CIQRCodeGenerator to create a QR code for the FFmpeg homepage,
5413 given as complete and escaped command-line for Apple's standard bash shell:
5415 ffmpeg -f lavfi -i nullsrc=s=100x100,coreimage=filter=CIQRCodeGenerator@@inputMessage=https\\\\\://FFmpeg.org/@@inputCorrectionLevel=H -frames:v 1 QRCode.png
5421 Crop the input video to given dimensions.
5423 It accepts the following parameters:
5427 The width of the output video. It defaults to @code{iw}.
5428 This expression is evaluated only once during the filter
5429 configuration, or when the @samp{w} or @samp{out_w} command is sent.
5432 The height of the output video. It defaults to @code{ih}.
5433 This expression is evaluated only once during the filter
5434 configuration, or when the @samp{h} or @samp{out_h} command is sent.
5437 The horizontal position, in the input video, of the left edge of the output
5438 video. It defaults to @code{(in_w-out_w)/2}.
5439 This expression is evaluated per-frame.
5442 The vertical position, in the input video, of the top edge of the output video.
5443 It defaults to @code{(in_h-out_h)/2}.
5444 This expression is evaluated per-frame.
5447 If set to 1 will force the output display aspect ratio
5448 to be the same of the input, by changing the output sample aspect
5449 ratio. It defaults to 0.
5452 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
5453 expressions containing the following constants:
5458 The computed values for @var{x} and @var{y}. They are evaluated for
5463 The input width and height.
5467 These are the same as @var{in_w} and @var{in_h}.
5471 The output (cropped) width and height.
5475 These are the same as @var{out_w} and @var{out_h}.
5478 same as @var{iw} / @var{ih}
5481 input sample aspect ratio
5484 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
5488 horizontal and vertical chroma subsample values. For example for the
5489 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5492 The number of the input frame, starting from 0.
5495 the position in the file of the input frame, NAN if unknown
5498 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
5502 The expression for @var{out_w} may depend on the value of @var{out_h},
5503 and the expression for @var{out_h} may depend on @var{out_w}, but they
5504 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
5505 evaluated after @var{out_w} and @var{out_h}.
5507 The @var{x} and @var{y} parameters specify the expressions for the
5508 position of the top-left corner of the output (non-cropped) area. They
5509 are evaluated for each frame. If the evaluated value is not valid, it
5510 is approximated to the nearest valid value.
5512 The expression for @var{x} may depend on @var{y}, and the expression
5513 for @var{y} may depend on @var{x}.
5515 @subsection Examples
5519 Crop area with size 100x100 at position (12,34).
5524 Using named options, the example above becomes:
5526 crop=w=100:h=100:x=12:y=34
5530 Crop the central input area with size 100x100:
5536 Crop the central input area with size 2/3 of the input video:
5538 crop=2/3*in_w:2/3*in_h
5542 Crop the input video central square:
5549 Delimit the rectangle with the top-left corner placed at position
5550 100:100 and the right-bottom corner corresponding to the right-bottom
5551 corner of the input image.
5553 crop=in_w-100:in_h-100:100:100
5557 Crop 10 pixels from the left and right borders, and 20 pixels from
5558 the top and bottom borders
5560 crop=in_w-2*10:in_h-2*20
5564 Keep only the bottom right quarter of the input image:
5566 crop=in_w/2:in_h/2:in_w/2:in_h/2
5570 Crop height for getting Greek harmony:
5572 crop=in_w:1/PHI*in_w
5576 Apply trembling effect:
5578 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)
5582 Apply erratic camera effect depending on timestamp:
5584 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)"
5588 Set x depending on the value of y:
5590 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
5594 @subsection Commands
5596 This filter supports the following commands:
5602 Set width/height of the output video and the horizontal/vertical position
5604 The command accepts the same syntax of the corresponding option.
5606 If the specified expression is not valid, it is kept at its current
5612 Auto-detect the crop size.
5614 It calculates the necessary cropping parameters and prints the
5615 recommended parameters via the logging system. The detected dimensions
5616 correspond to the non-black area of the input video.
5618 It accepts the following parameters:
5623 Set higher black value threshold, which can be optionally specified
5624 from nothing (0) to everything (255 for 8bit based formats). An intensity
5625 value greater to the set value is considered non-black. It defaults to 24.
5626 You can also specify a value between 0.0 and 1.0 which will be scaled depending
5627 on the bitdepth of the pixel format.
5630 The value which the width/height should be divisible by. It defaults to
5631 16. The offset is automatically adjusted to center the video. Use 2 to
5632 get only even dimensions (needed for 4:2:2 video). 16 is best when
5633 encoding to most video codecs.
5635 @item reset_count, reset
5636 Set the counter that determines after how many frames cropdetect will
5637 reset the previously detected largest video area and start over to
5638 detect the current optimal crop area. Default value is 0.
5640 This can be useful when channel logos distort the video area. 0
5641 indicates 'never reset', and returns the largest area encountered during
5648 Apply color adjustments using curves.
5650 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
5651 component (red, green and blue) has its values defined by @var{N} key points
5652 tied from each other using a smooth curve. The x-axis represents the pixel
5653 values from the input frame, and the y-axis the new pixel values to be set for
5656 By default, a component curve is defined by the two points @var{(0;0)} and
5657 @var{(1;1)}. This creates a straight line where each original pixel value is
5658 "adjusted" to its own value, which means no change to the image.
5660 The filter allows you to redefine these two points and add some more. A new
5661 curve (using a natural cubic spline interpolation) will be define to pass
5662 smoothly through all these new coordinates. The new defined points needs to be
5663 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
5664 be in the @var{[0;1]} interval. If the computed curves happened to go outside
5665 the vector spaces, the values will be clipped accordingly.
5667 If there is no key point defined in @code{x=0}, the filter will automatically
5668 insert a @var{(0;0)} point. In the same way, if there is no key point defined
5669 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
5671 The filter accepts the following options:
5675 Select one of the available color presets. This option can be used in addition
5676 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
5677 options takes priority on the preset values.
5678 Available presets are:
5681 @item color_negative
5684 @item increase_contrast
5686 @item linear_contrast
5687 @item medium_contrast
5689 @item strong_contrast
5692 Default is @code{none}.
5694 Set the master key points. These points will define a second pass mapping. It
5695 is sometimes called a "luminance" or "value" mapping. It can be used with
5696 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
5697 post-processing LUT.
5699 Set the key points for the red component.
5701 Set the key points for the green component.
5703 Set the key points for the blue component.
5705 Set the key points for all components (not including master).
5706 Can be used in addition to the other key points component
5707 options. In this case, the unset component(s) will fallback on this
5708 @option{all} setting.
5710 Specify a Photoshop curves file (@code{.acv}) to import the settings from.
5713 To avoid some filtergraph syntax conflicts, each key points list need to be
5714 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
5716 @subsection Examples
5720 Increase slightly the middle level of blue:
5722 curves=blue='0.5/0.58'
5728 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
5730 Here we obtain the following coordinates for each components:
5733 @code{(0;0.11) (0.42;0.51) (1;0.95)}
5735 @code{(0;0) (0.50;0.48) (1;1)}
5737 @code{(0;0.22) (0.49;0.44) (1;0.80)}
5741 The previous example can also be achieved with the associated built-in preset:
5743 curves=preset=vintage
5753 Use a Photoshop preset and redefine the points of the green component:
5755 curves=psfile='MyCurvesPresets/purple.acv':green='0.45/0.53'
5761 Video data analysis filter.
5763 This filter shows hexadecimal pixel values of part of video.
5765 The filter accepts the following options:
5769 Set output video size.
5772 Set x offset from where to pick pixels.
5775 Set y offset from where to pick pixels.
5778 Set scope mode, can be one of the following:
5781 Draw hexadecimal pixel values with white color on black background.
5784 Draw hexadecimal pixel values with input video pixel color on black
5788 Draw hexadecimal pixel values on color background picked from input video,
5789 the text color is picked in such way so its always visible.
5793 Draw rows and columns numbers on left and top of video.
5798 Denoise frames using 2D DCT (frequency domain filtering).
5800 This filter is not designed for real time.
5802 The filter accepts the following options:
5806 Set the noise sigma constant.
5808 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
5809 coefficient (absolute value) below this threshold with be dropped.
5811 If you need a more advanced filtering, see @option{expr}.
5813 Default is @code{0}.
5816 Set number overlapping pixels for each block. Since the filter can be slow, you
5817 may want to reduce this value, at the cost of a less effective filter and the
5818 risk of various artefacts.
5820 If the overlapping value doesn't permit processing the whole input width or
5821 height, a warning will be displayed and according borders won't be denoised.
5823 Default value is @var{blocksize}-1, which is the best possible setting.
5826 Set the coefficient factor expression.
5828 For each coefficient of a DCT block, this expression will be evaluated as a
5829 multiplier value for the coefficient.
5831 If this is option is set, the @option{sigma} option will be ignored.
5833 The absolute value of the coefficient can be accessed through the @var{c}
5837 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
5838 @var{blocksize}, which is the width and height of the processed blocks.
5840 The default value is @var{3} (8x8) and can be raised to @var{4} for a
5841 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
5842 on the speed processing. Also, a larger block size does not necessarily means a
5846 @subsection Examples
5848 Apply a denoise with a @option{sigma} of @code{4.5}:
5853 The same operation can be achieved using the expression system:
5855 dctdnoiz=e='gte(c, 4.5*3)'
5858 Violent denoise using a block size of @code{16x16}:
5865 Remove banding artifacts from input video.
5866 It works by replacing banded pixels with average value of referenced pixels.
5868 The filter accepts the following options:
5875 Set banding detection threshold for each plane. Default is 0.02.
5876 Valid range is 0.00003 to 0.5.
5877 If difference between current pixel and reference pixel is less than threshold,
5878 it will be considered as banded.
5881 Banding detection range in pixels. Default is 16. If positive, random number
5882 in range 0 to set value will be used. If negative, exact absolute value
5884 The range defines square of four pixels around current pixel.
5887 Set direction in radians from which four pixel will be compared. If positive,
5888 random direction from 0 to set direction will be picked. If negative, exact of
5889 absolute value will be picked. For example direction 0, -PI or -2*PI radians
5890 will pick only pixels on same row and -PI/2 will pick only pixels on same
5894 If enabled, current pixel is compared with average value of all four
5895 surrounding pixels. The default is enabled. If disabled current pixel is
5896 compared with all four surrounding pixels. The pixel is considered banded
5897 if only all four differences with surrounding pixels are less than threshold.
5903 Drop duplicated frames at regular intervals.
5905 The filter accepts the following options:
5909 Set the number of frames from which one will be dropped. Setting this to
5910 @var{N} means one frame in every batch of @var{N} frames will be dropped.
5911 Default is @code{5}.
5914 Set the threshold for duplicate detection. If the difference metric for a frame
5915 is less than or equal to this value, then it is declared as duplicate. Default
5919 Set scene change threshold. Default is @code{15}.
5923 Set the size of the x and y-axis blocks used during metric calculations.
5924 Larger blocks give better noise suppression, but also give worse detection of
5925 small movements. Must be a power of two. Default is @code{32}.
5928 Mark main input as a pre-processed input and activate clean source input
5929 stream. This allows the input to be pre-processed with various filters to help
5930 the metrics calculation while keeping the frame selection lossless. When set to
5931 @code{1}, the first stream is for the pre-processed input, and the second
5932 stream is the clean source from where the kept frames are chosen. Default is
5936 Set whether or not chroma is considered in the metric calculations. Default is
5942 Apply deflate effect to the video.
5944 This filter replaces the pixel by the local(3x3) average by taking into account
5945 only values lower than the pixel.
5947 It accepts the following options:
5954 Limit the maximum change for each plane, default is 65535.
5955 If 0, plane will remain unchanged.
5960 Remove judder produced by partially interlaced telecined content.
5962 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
5963 source was partially telecined content then the output of @code{pullup,dejudder}
5964 will have a variable frame rate. May change the recorded frame rate of the
5965 container. Aside from that change, this filter will not affect constant frame
5968 The option available in this filter is:
5972 Specify the length of the window over which the judder repeats.
5974 Accepts any integer greater than 1. Useful values are:
5978 If the original was telecined from 24 to 30 fps (Film to NTSC).
5981 If the original was telecined from 25 to 30 fps (PAL to NTSC).
5984 If a mixture of the two.
5987 The default is @samp{4}.
5992 Suppress a TV station logo by a simple interpolation of the surrounding
5993 pixels. Just set a rectangle covering the logo and watch it disappear
5994 (and sometimes something even uglier appear - your mileage may vary).
5996 It accepts the following parameters:
6001 Specify the top left corner coordinates of the logo. They must be
6006 Specify the width and height of the logo to clear. They must be
6010 Specify the thickness of the fuzzy edge of the rectangle (added to
6011 @var{w} and @var{h}). The default value is 1. This option is
6012 deprecated, setting higher values should no longer be necessary and
6016 When set to 1, a green rectangle is drawn on the screen to simplify
6017 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
6018 The default value is 0.
6020 The rectangle is drawn on the outermost pixels which will be (partly)
6021 replaced with interpolated values. The values of the next pixels
6022 immediately outside this rectangle in each direction will be used to
6023 compute the interpolated pixel values inside the rectangle.
6027 @subsection Examples
6031 Set a rectangle covering the area with top left corner coordinates 0,0
6032 and size 100x77, and a band of size 10:
6034 delogo=x=0:y=0:w=100:h=77:band=10
6041 Attempt to fix small changes in horizontal and/or vertical shift. This
6042 filter helps remove camera shake from hand-holding a camera, bumping a
6043 tripod, moving on a vehicle, etc.
6045 The filter accepts the following options:
6053 Specify a rectangular area where to limit the search for motion
6055 If desired the search for motion vectors can be limited to a
6056 rectangular area of the frame defined by its top left corner, width
6057 and height. These parameters have the same meaning as the drawbox
6058 filter which can be used to visualise the position of the bounding
6061 This is useful when simultaneous movement of subjects within the frame
6062 might be confused for camera motion by the motion vector search.
6064 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
6065 then the full frame is used. This allows later options to be set
6066 without specifying the bounding box for the motion vector search.
6068 Default - search the whole frame.
6072 Specify the maximum extent of movement in x and y directions in the
6073 range 0-64 pixels. Default 16.
6076 Specify how to generate pixels to fill blanks at the edge of the
6077 frame. Available values are:
6080 Fill zeroes at blank locations
6082 Original image at blank locations
6084 Extruded edge value at blank locations
6086 Mirrored edge at blank locations
6088 Default value is @samp{mirror}.
6091 Specify the blocksize to use for motion search. Range 4-128 pixels,
6095 Specify the contrast threshold for blocks. Only blocks with more than
6096 the specified contrast (difference between darkest and lightest
6097 pixels) will be considered. Range 1-255, default 125.
6100 Specify the search strategy. Available values are:
6103 Set exhaustive search
6105 Set less exhaustive search.
6107 Default value is @samp{exhaustive}.
6110 If set then a detailed log of the motion search is written to the
6114 If set to 1, specify using OpenCL capabilities, only available if
6115 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
6121 Apply an exact inverse of the telecine operation. It requires a predefined
6122 pattern specified using the pattern option which must be the same as that passed
6123 to the telecine filter.
6125 This filter accepts the following options:
6134 The default value is @code{top}.
6138 A string of numbers representing the pulldown pattern you wish to apply.
6139 The default value is @code{23}.
6142 A number representing position of the first frame with respect to the telecine
6143 pattern. This is to be used if the stream is cut. The default value is @code{0}.
6148 Apply dilation effect to the video.
6150 This filter replaces the pixel by the local(3x3) maximum.
6152 It accepts the following options:
6159 Limit the maximum change for each plane, default is 65535.
6160 If 0, plane will remain unchanged.
6163 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
6166 Flags to local 3x3 coordinates maps like this:
6175 Displace pixels as indicated by second and third input stream.
6177 It takes three input streams and outputs one stream, the first input is the
6178 source, and second and third input are displacement maps.
6180 The second input specifies how much to displace pixels along the
6181 x-axis, while the third input specifies how much to displace pixels
6183 If one of displacement map streams terminates, last frame from that
6184 displacement map will be used.
6186 Note that once generated, displacements maps can be reused over and over again.
6188 A description of the accepted options follows.
6192 Set displace behavior for pixels that are out of range.
6194 Available values are:
6197 Missing pixels are replaced by black pixels.
6200 Adjacent pixels will spread out to replace missing pixels.
6203 Out of range pixels are wrapped so they point to pixels of other side.
6205 Default is @samp{smear}.
6209 @subsection Examples
6213 Add ripple effect to rgb input of video size hd720:
6215 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
6219 Add wave effect to rgb input of video size hd720:
6221 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
6227 Draw a colored box on the input image.
6229 It accepts the following parameters:
6234 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
6238 The expressions which specify the width and height of the box; if 0 they are interpreted as
6239 the input width and height. It defaults to 0.
6242 Specify the color of the box to write. For the general syntax of this option,
6243 check the "Color" section in the ffmpeg-utils manual. If the special
6244 value @code{invert} is used, the box edge color is the same as the
6245 video with inverted luma.
6248 The expression which sets the thickness of the box edge. Default value is @code{3}.
6250 See below for the list of accepted constants.
6253 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
6254 following constants:
6258 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
6262 horizontal and vertical chroma subsample values. For example for the
6263 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6267 The input width and height.
6270 The input sample aspect ratio.
6274 The x and y offset coordinates where the box is drawn.
6278 The width and height of the drawn box.
6281 The thickness of the drawn box.
6283 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
6284 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
6288 @subsection Examples
6292 Draw a black box around the edge of the input image:
6298 Draw a box with color red and an opacity of 50%:
6300 drawbox=10:20:200:60:red@@0.5
6303 The previous example can be specified as:
6305 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
6309 Fill the box with pink color:
6311 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
6315 Draw a 2-pixel red 2.40:1 mask:
6317 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
6321 @section drawgraph, adrawgraph
6323 Draw a graph using input video or audio metadata.
6325 It accepts the following parameters:
6329 Set 1st frame metadata key from which metadata values will be used to draw a graph.
6332 Set 1st foreground color expression.
6335 Set 2nd frame metadata key from which metadata values will be used to draw a graph.
6338 Set 2nd foreground color expression.
6341 Set 3rd frame metadata key from which metadata values will be used to draw a graph.
6344 Set 3rd foreground color expression.
6347 Set 4th frame metadata key from which metadata values will be used to draw a graph.
6350 Set 4th foreground color expression.
6353 Set minimal value of metadata value.
6356 Set maximal value of metadata value.
6359 Set graph background color. Default is white.
6364 Available values for mode is:
6371 Default is @code{line}.
6376 Available values for slide is:
6379 Draw new frame when right border is reached.
6382 Replace old columns with new ones.
6385 Scroll from right to left.
6388 Scroll from left to right.
6391 Default is @code{frame}.
6394 Set size of graph video. For the syntax of this option, check the
6395 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
6396 The default value is @code{900x256}.
6398 The foreground color expressions can use the following variables:
6401 Minimal value of metadata value.
6404 Maximal value of metadata value.
6407 Current metadata key value.
6410 The color is defined as 0xAABBGGRR.
6413 Example using metadata from @ref{signalstats} filter:
6415 signalstats,drawgraph=lavfi.signalstats.YAVG:min=0:max=255
6418 Example using metadata from @ref{ebur128} filter:
6420 ebur128=metadata=1,adrawgraph=lavfi.r128.M:min=-120:max=5
6425 Draw a grid on the input image.
6427 It accepts the following parameters:
6432 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
6436 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
6437 input width and height, respectively, minus @code{thickness}, so image gets
6438 framed. Default to 0.
6441 Specify the color of the grid. For the general syntax of this option,
6442 check the "Color" section in the ffmpeg-utils manual. If the special
6443 value @code{invert} is used, the grid color is the same as the
6444 video with inverted luma.
6447 The expression which sets the thickness of the grid line. Default value is @code{1}.
6449 See below for the list of accepted constants.
6452 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
6453 following constants:
6457 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
6461 horizontal and vertical chroma subsample values. For example for the
6462 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6466 The input grid cell width and height.
6469 The input sample aspect ratio.
6473 The x and y coordinates of some point of grid intersection (meant to configure offset).
6477 The width and height of the drawn cell.
6480 The thickness of the drawn cell.
6482 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
6483 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
6487 @subsection Examples
6491 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
6493 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
6497 Draw a white 3x3 grid with an opacity of 50%:
6499 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
6506 Draw a text string or text from a specified file on top of a video, using the
6507 libfreetype library.
6509 To enable compilation of this filter, you need to configure FFmpeg with
6510 @code{--enable-libfreetype}.
6511 To enable default font fallback and the @var{font} option you need to
6512 configure FFmpeg with @code{--enable-libfontconfig}.
6513 To enable the @var{text_shaping} option, you need to configure FFmpeg with
6514 @code{--enable-libfribidi}.
6518 It accepts the following parameters:
6523 Used to draw a box around text using the background color.
6524 The value must be either 1 (enable) or 0 (disable).
6525 The default value of @var{box} is 0.
6528 Set the width of the border to be drawn around the box using @var{boxcolor}.
6529 The default value of @var{boxborderw} is 0.
6532 The color to be used for drawing box around text. For the syntax of this
6533 option, check the "Color" section in the ffmpeg-utils manual.
6535 The default value of @var{boxcolor} is "white".
6538 Set the width of the border to be drawn around the text using @var{bordercolor}.
6539 The default value of @var{borderw} is 0.
6542 Set the color to be used for drawing border around text. For the syntax of this
6543 option, check the "Color" section in the ffmpeg-utils manual.
6545 The default value of @var{bordercolor} is "black".
6548 Select how the @var{text} is expanded. Can be either @code{none},
6549 @code{strftime} (deprecated) or
6550 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
6554 If true, check and fix text coords to avoid clipping.
6557 The color to be used for drawing fonts. For the syntax of this option, check
6558 the "Color" section in the ffmpeg-utils manual.
6560 The default value of @var{fontcolor} is "black".
6562 @item fontcolor_expr
6563 String which is expanded the same way as @var{text} to obtain dynamic
6564 @var{fontcolor} value. By default this option has empty value and is not
6565 processed. When this option is set, it overrides @var{fontcolor} option.
6568 The font family to be used for drawing text. By default Sans.
6571 The font file to be used for drawing text. The path must be included.
6572 This parameter is mandatory if the fontconfig support is disabled.
6575 This option does not exist, please see the timeline system
6578 Draw the text applying alpha blending. The value can
6579 be either a number between 0.0 and 1.0
6580 The expression accepts the same variables @var{x, y} do.
6581 The default value is 1.
6582 Please see fontcolor_expr
6585 The font size to be used for drawing text.
6586 The default value of @var{fontsize} is 16.
6589 If set to 1, attempt to shape the text (for example, reverse the order of
6590 right-to-left text and join Arabic characters) before drawing it.
6591 Otherwise, just draw the text exactly as given.
6592 By default 1 (if supported).
6595 The flags to be used for loading the fonts.
6597 The flags map the corresponding flags supported by libfreetype, and are
6598 a combination of the following values:
6605 @item vertical_layout
6606 @item force_autohint
6609 @item ignore_global_advance_width
6611 @item ignore_transform
6617 Default value is "default".
6619 For more information consult the documentation for the FT_LOAD_*
6623 The color to be used for drawing a shadow behind the drawn text. For the
6624 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
6626 The default value of @var{shadowcolor} is "black".
6630 The x and y offsets for the text shadow position with respect to the
6631 position of the text. They can be either positive or negative
6632 values. The default value for both is "0".
6635 The starting frame number for the n/frame_num variable. The default value
6639 The size in number of spaces to use for rendering the tab.
6643 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
6644 format. It can be used with or without text parameter. @var{timecode_rate}
6645 option must be specified.
6647 @item timecode_rate, rate, r
6648 Set the timecode frame rate (timecode only).
6651 The text string to be drawn. The text must be a sequence of UTF-8
6653 This parameter is mandatory if no file is specified with the parameter
6657 A text file containing text to be drawn. The text must be a sequence
6658 of UTF-8 encoded characters.
6660 This parameter is mandatory if no text string is specified with the
6661 parameter @var{text}.
6663 If both @var{text} and @var{textfile} are specified, an error is thrown.
6666 If set to 1, the @var{textfile} will be reloaded before each frame.
6667 Be sure to update it atomically, or it may be read partially, or even fail.
6671 The expressions which specify the offsets where text will be drawn
6672 within the video frame. They are relative to the top/left border of the
6675 The default value of @var{x} and @var{y} is "0".
6677 See below for the list of accepted constants and functions.
6680 The parameters for @var{x} and @var{y} are expressions containing the
6681 following constants and functions:
6685 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
6689 horizontal and vertical chroma subsample values. For example for the
6690 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6693 the height of each text line
6701 @item max_glyph_a, ascent
6702 the maximum distance from the baseline to the highest/upper grid
6703 coordinate used to place a glyph outline point, for all the rendered
6705 It is a positive value, due to the grid's orientation with the Y axis
6708 @item max_glyph_d, descent
6709 the maximum distance from the baseline to the lowest grid coordinate
6710 used to place a glyph outline point, for all the rendered glyphs.
6711 This is a negative value, due to the grid's orientation, with the Y axis
6715 maximum glyph height, that is the maximum height for all the glyphs
6716 contained in the rendered text, it is equivalent to @var{ascent} -
6720 maximum glyph width, that is the maximum width for all the glyphs
6721 contained in the rendered text
6724 the number of input frame, starting from 0
6726 @item rand(min, max)
6727 return a random number included between @var{min} and @var{max}
6730 The input sample aspect ratio.
6733 timestamp expressed in seconds, NAN if the input timestamp is unknown
6736 the height of the rendered text
6739 the width of the rendered text
6743 the x and y offset coordinates where the text is drawn.
6745 These parameters allow the @var{x} and @var{y} expressions to refer
6746 each other, so you can for example specify @code{y=x/dar}.
6749 @anchor{drawtext_expansion}
6750 @subsection Text expansion
6752 If @option{expansion} is set to @code{strftime},
6753 the filter recognizes strftime() sequences in the provided text and
6754 expands them accordingly. Check the documentation of strftime(). This
6755 feature is deprecated.
6757 If @option{expansion} is set to @code{none}, the text is printed verbatim.
6759 If @option{expansion} is set to @code{normal} (which is the default),
6760 the following expansion mechanism is used.
6762 The backslash character @samp{\}, followed by any character, always expands to
6763 the second character.
6765 Sequence of the form @code{%@{...@}} are expanded. The text between the
6766 braces is a function name, possibly followed by arguments separated by ':'.
6767 If the arguments contain special characters or delimiters (':' or '@}'),
6768 they should be escaped.
6770 Note that they probably must also be escaped as the value for the
6771 @option{text} option in the filter argument string and as the filter
6772 argument in the filtergraph description, and possibly also for the shell,
6773 that makes up to four levels of escaping; using a text file avoids these
6776 The following functions are available:
6781 The expression evaluation result.
6783 It must take one argument specifying the expression to be evaluated,
6784 which accepts the same constants and functions as the @var{x} and
6785 @var{y} values. Note that not all constants should be used, for
6786 example the text size is not known when evaluating the expression, so
6787 the constants @var{text_w} and @var{text_h} will have an undefined
6790 @item expr_int_format, eif
6791 Evaluate the expression's value and output as formatted integer.
6793 The first argument is the expression to be evaluated, just as for the @var{expr} function.
6794 The second argument specifies the output format. Allowed values are @samp{x},
6795 @samp{X}, @samp{d} and @samp{u}. They are treated exactly as in the
6796 @code{printf} function.
6797 The third parameter is optional and sets the number of positions taken by the output.
6798 It can be used to add padding with zeros from the left.
6801 The time at which the filter is running, expressed in UTC.
6802 It can accept an argument: a strftime() format string.
6805 The time at which the filter is running, expressed in the local time zone.
6806 It can accept an argument: a strftime() format string.
6809 Frame metadata. Takes one or two arguments.
6811 The first argument is mandatory and specifies the metadata key.
6813 The second argument is optional and specifies a default value, used when the
6814 metadata key is not found or empty.
6817 The frame number, starting from 0.
6820 A 1 character description of the current picture type.
6823 The timestamp of the current frame.
6824 It can take up to three arguments.
6826 The first argument is the format of the timestamp; it defaults to @code{flt}
6827 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
6828 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
6829 @code{gmtime} stands for the timestamp of the frame formatted as UTC time;
6830 @code{localtime} stands for the timestamp of the frame formatted as
6831 local time zone time.
6833 The second argument is an offset added to the timestamp.
6835 If the format is set to @code{localtime} or @code{gmtime},
6836 a third argument may be supplied: a strftime() format string.
6837 By default, @var{YYYY-MM-DD HH:MM:SS} format will be used.
6840 @subsection Examples
6844 Draw "Test Text" with font FreeSerif, using the default values for the
6845 optional parameters.
6848 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
6852 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
6853 and y=50 (counting from the top-left corner of the screen), text is
6854 yellow with a red box around it. Both the text and the box have an
6858 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
6859 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
6862 Note that the double quotes are not necessary if spaces are not used
6863 within the parameter list.
6866 Show the text at the center of the video frame:
6868 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h)/2"
6872 Show the text at a random position, switching to a new position every 30 seconds:
6874 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)"
6878 Show a text line sliding from right to left in the last row of the video
6879 frame. The file @file{LONG_LINE} is assumed to contain a single line
6882 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
6886 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
6888 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
6892 Draw a single green letter "g", at the center of the input video.
6893 The glyph baseline is placed at half screen height.
6895 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
6899 Show text for 1 second every 3 seconds:
6901 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
6905 Use fontconfig to set the font. Note that the colons need to be escaped.
6907 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
6911 Print the date of a real-time encoding (see strftime(3)):
6913 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
6917 Show text fading in and out (appearing/disappearing):
6920 DS=1.0 # display start
6921 DE=10.0 # display end
6922 FID=1.5 # fade in duration
6923 FOD=5 # fade out duration
6924 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 @}"
6929 For more information about libfreetype, check:
6930 @url{http://www.freetype.org/}.
6932 For more information about fontconfig, check:
6933 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
6935 For more information about libfribidi, check:
6936 @url{http://fribidi.org/}.
6940 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
6942 The filter accepts the following options:
6947 Set low and high threshold values used by the Canny thresholding
6950 The high threshold selects the "strong" edge pixels, which are then
6951 connected through 8-connectivity with the "weak" edge pixels selected
6952 by the low threshold.
6954 @var{low} and @var{high} threshold values must be chosen in the range
6955 [0,1], and @var{low} should be lesser or equal to @var{high}.
6957 Default value for @var{low} is @code{20/255}, and default value for @var{high}
6961 Define the drawing mode.
6965 Draw white/gray wires on black background.
6968 Mix the colors to create a paint/cartoon effect.
6971 Default value is @var{wires}.
6974 @subsection Examples
6978 Standard edge detection with custom values for the hysteresis thresholding:
6980 edgedetect=low=0.1:high=0.4
6984 Painting effect without thresholding:
6986 edgedetect=mode=colormix:high=0
6991 Set brightness, contrast, saturation and approximate gamma adjustment.
6993 The filter accepts the following options:
6997 Set the contrast expression. The value must be a float value in range
6998 @code{-2.0} to @code{2.0}. The default value is "1".
7001 Set the brightness expression. The value must be a float value in
7002 range @code{-1.0} to @code{1.0}. The default value is "0".
7005 Set the saturation expression. The value must be a float in
7006 range @code{0.0} to @code{3.0}. The default value is "1".
7009 Set the gamma expression. The value must be a float in range
7010 @code{0.1} to @code{10.0}. The default value is "1".
7013 Set the gamma expression for red. The value must be a float in
7014 range @code{0.1} to @code{10.0}. The default value is "1".
7017 Set the gamma expression for green. The value must be a float in range
7018 @code{0.1} to @code{10.0}. The default value is "1".
7021 Set the gamma expression for blue. The value must be a float in range
7022 @code{0.1} to @code{10.0}. The default value is "1".
7025 Set the gamma weight expression. It can be used to reduce the effect
7026 of a high gamma value on bright image areas, e.g. keep them from
7027 getting overamplified and just plain white. The value must be a float
7028 in range @code{0.0} to @code{1.0}. A value of @code{0.0} turns the
7029 gamma correction all the way down while @code{1.0} leaves it at its
7030 full strength. Default is "1".
7033 Set when the expressions for brightness, contrast, saturation and
7034 gamma expressions are evaluated.
7036 It accepts the following values:
7039 only evaluate expressions once during the filter initialization or
7040 when a command is processed
7043 evaluate expressions for each incoming frame
7046 Default value is @samp{init}.
7049 The expressions accept the following parameters:
7052 frame count of the input frame starting from 0
7055 byte position of the corresponding packet in the input file, NAN if
7059 frame rate of the input video, NAN if the input frame rate is unknown
7062 timestamp expressed in seconds, NAN if the input timestamp is unknown
7065 @subsection Commands
7066 The filter supports the following commands:
7070 Set the contrast expression.
7073 Set the brightness expression.
7076 Set the saturation expression.
7079 Set the gamma expression.
7082 Set the gamma_r expression.
7085 Set gamma_g expression.
7088 Set gamma_b expression.
7091 Set gamma_weight expression.
7093 The command accepts the same syntax of the corresponding option.
7095 If the specified expression is not valid, it is kept at its current
7102 Apply erosion effect to the video.
7104 This filter replaces the pixel by the local(3x3) minimum.
7106 It accepts the following options:
7113 Limit the maximum change for each plane, default is 65535.
7114 If 0, plane will remain unchanged.
7117 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
7120 Flags to local 3x3 coordinates maps like this:
7127 @section extractplanes
7129 Extract color channel components from input video stream into
7130 separate grayscale video streams.
7132 The filter accepts the following option:
7136 Set plane(s) to extract.
7138 Available values for planes are:
7149 Choosing planes not available in the input will result in an error.
7150 That means you cannot select @code{r}, @code{g}, @code{b} planes
7151 with @code{y}, @code{u}, @code{v} planes at same time.
7154 @subsection Examples
7158 Extract luma, u and v color channel component from input video frame
7159 into 3 grayscale outputs:
7161 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
7167 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
7169 For each input image, the filter will compute the optimal mapping from
7170 the input to the output given the codebook length, that is the number
7171 of distinct output colors.
7173 This filter accepts the following options.
7176 @item codebook_length, l
7177 Set codebook length. The value must be a positive integer, and
7178 represents the number of distinct output colors. Default value is 256.
7181 Set the maximum number of iterations to apply for computing the optimal
7182 mapping. The higher the value the better the result and the higher the
7183 computation time. Default value is 1.
7186 Set a random seed, must be an integer included between 0 and
7187 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
7188 will try to use a good random seed on a best effort basis.
7191 Set pal8 output pixel format. This option does not work with codebook
7192 length greater than 256.
7197 Apply a fade-in/out effect to the input video.
7199 It accepts the following parameters:
7203 The effect type can be either "in" for a fade-in, or "out" for a fade-out
7205 Default is @code{in}.
7207 @item start_frame, s
7208 Specify the number of the frame to start applying the fade
7209 effect at. Default is 0.
7212 The number of frames that the fade effect lasts. At the end of the
7213 fade-in effect, the output video will have the same intensity as the input video.
7214 At the end of the fade-out transition, the output video will be filled with the
7215 selected @option{color}.
7219 If set to 1, fade only alpha channel, if one exists on the input.
7222 @item start_time, st
7223 Specify the timestamp (in seconds) of the frame to start to apply the fade
7224 effect. If both start_frame and start_time are specified, the fade will start at
7225 whichever comes last. Default is 0.
7228 The number of seconds for which the fade effect has to last. At the end of the
7229 fade-in effect the output video will have the same intensity as the input video,
7230 at the end of the fade-out transition the output video will be filled with the
7231 selected @option{color}.
7232 If both duration and nb_frames are specified, duration is used. Default is 0
7233 (nb_frames is used by default).
7236 Specify the color of the fade. Default is "black".
7239 @subsection Examples
7243 Fade in the first 30 frames of video:
7248 The command above is equivalent to:
7254 Fade out the last 45 frames of a 200-frame video:
7257 fade=type=out:start_frame=155:nb_frames=45
7261 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
7263 fade=in:0:25, fade=out:975:25
7267 Make the first 5 frames yellow, then fade in from frame 5-24:
7269 fade=in:5:20:color=yellow
7273 Fade in alpha over first 25 frames of video:
7275 fade=in:0:25:alpha=1
7279 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
7281 fade=t=in:st=5.5:d=0.5
7287 Apply arbitrary expressions to samples in frequency domain
7291 Adjust the dc value (gain) of the luma plane of the image. The filter
7292 accepts an integer value in range @code{0} to @code{1000}. The default
7293 value is set to @code{0}.
7296 Adjust the dc value (gain) of the 1st chroma plane of the image. The
7297 filter accepts an integer value in range @code{0} to @code{1000}. The
7298 default value is set to @code{0}.
7301 Adjust the dc value (gain) of the 2nd chroma plane of the image. The
7302 filter accepts an integer value in range @code{0} to @code{1000}. The
7303 default value is set to @code{0}.
7306 Set the frequency domain weight expression for the luma plane.
7309 Set the frequency domain weight expression for the 1st chroma plane.
7312 Set the frequency domain weight expression for the 2nd chroma plane.
7314 The filter accepts the following variables:
7317 The coordinates of the current sample.
7321 The width and height of the image.
7324 @subsection Examples
7330 fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
7336 fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
7342 fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
7348 fftfilt=dc_Y=0:weight_Y='exp(-4 * ((Y+X)/(W+H)))'
7355 Extract a single field from an interlaced image using stride
7356 arithmetic to avoid wasting CPU time. The output frames are marked as
7359 The filter accepts the following options:
7363 Specify whether to extract the top (if the value is @code{0} or
7364 @code{top}) or the bottom field (if the value is @code{1} or
7370 Create new frames by copying the top and bottom fields from surrounding frames
7371 supplied as numbers by the hint file.
7375 Set file containing hints: absolute/relative frame numbers.
7377 There must be one line for each frame in a clip. Each line must contain two
7378 numbers separated by the comma, optionally followed by @code{-} or @code{+}.
7379 Numbers supplied on each line of file can not be out of [N-1,N+1] where N
7380 is current frame number for @code{absolute} mode or out of [-1, 1] range
7381 for @code{relative} mode. First number tells from which frame to pick up top
7382 field and second number tells from which frame to pick up bottom field.
7384 If optionally followed by @code{+} output frame will be marked as interlaced,
7385 else if followed by @code{-} output frame will be marked as progressive, else
7386 it will be marked same as input frame.
7387 If line starts with @code{#} or @code{;} that line is skipped.
7390 Can be item @code{absolute} or @code{relative}. Default is @code{absolute}.
7393 Example of first several lines of @code{hint} file for @code{relative} mode:
7396 1,0 - # second frame, use third's frame top field and second's frame bottom field
7397 1,0 - # third frame, use fourth's frame top field and third's frame bottom field
7414 Field matching filter for inverse telecine. It is meant to reconstruct the
7415 progressive frames from a telecined stream. The filter does not drop duplicated
7416 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
7417 followed by a decimation filter such as @ref{decimate} in the filtergraph.
7419 The separation of the field matching and the decimation is notably motivated by
7420 the possibility of inserting a de-interlacing filter fallback between the two.
7421 If the source has mixed telecined and real interlaced content,
7422 @code{fieldmatch} will not be able to match fields for the interlaced parts.
7423 But these remaining combed frames will be marked as interlaced, and thus can be
7424 de-interlaced by a later filter such as @ref{yadif} before decimation.
7426 In addition to the various configuration options, @code{fieldmatch} can take an
7427 optional second stream, activated through the @option{ppsrc} option. If
7428 enabled, the frames reconstruction will be based on the fields and frames from
7429 this second stream. This allows the first input to be pre-processed in order to
7430 help the various algorithms of the filter, while keeping the output lossless
7431 (assuming the fields are matched properly). Typically, a field-aware denoiser,
7432 or brightness/contrast adjustments can help.
7434 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
7435 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
7436 which @code{fieldmatch} is based on. While the semantic and usage are very
7437 close, some behaviour and options names can differ.
7439 The @ref{decimate} filter currently only works for constant frame rate input.
7440 If your input has mixed telecined (30fps) and progressive content with a lower
7441 framerate like 24fps use the following filterchain to produce the necessary cfr
7442 stream: @code{dejudder,fps=30000/1001,fieldmatch,decimate}.
7444 The filter accepts the following options:
7448 Specify the assumed field order of the input stream. Available values are:
7452 Auto detect parity (use FFmpeg's internal parity value).
7454 Assume bottom field first.
7456 Assume top field first.
7459 Note that it is sometimes recommended not to trust the parity announced by the
7462 Default value is @var{auto}.
7465 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
7466 sense that it won't risk creating jerkiness due to duplicate frames when
7467 possible, but if there are bad edits or blended fields it will end up
7468 outputting combed frames when a good match might actually exist. On the other
7469 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
7470 but will almost always find a good frame if there is one. The other values are
7471 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
7472 jerkiness and creating duplicate frames versus finding good matches in sections
7473 with bad edits, orphaned fields, blended fields, etc.
7475 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
7477 Available values are:
7481 2-way matching (p/c)
7483 2-way matching, and trying 3rd match if still combed (p/c + n)
7485 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
7487 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
7488 still combed (p/c + n + u/b)
7490 3-way matching (p/c/n)
7492 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
7493 detected as combed (p/c/n + u/b)
7496 The parenthesis at the end indicate the matches that would be used for that
7497 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
7500 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
7503 Default value is @var{pc_n}.
7506 Mark the main input stream as a pre-processed input, and enable the secondary
7507 input stream as the clean source to pick the fields from. See the filter
7508 introduction for more details. It is similar to the @option{clip2} feature from
7511 Default value is @code{0} (disabled).
7514 Set the field to match from. It is recommended to set this to the same value as
7515 @option{order} unless you experience matching failures with that setting. In
7516 certain circumstances changing the field that is used to match from can have a
7517 large impact on matching performance. Available values are:
7521 Automatic (same value as @option{order}).
7523 Match from the bottom field.
7525 Match from the top field.
7528 Default value is @var{auto}.
7531 Set whether or not chroma is included during the match comparisons. In most
7532 cases it is recommended to leave this enabled. You should set this to @code{0}
7533 only if your clip has bad chroma problems such as heavy rainbowing or other
7534 artifacts. Setting this to @code{0} could also be used to speed things up at
7535 the cost of some accuracy.
7537 Default value is @code{1}.
7541 These define an exclusion band which excludes the lines between @option{y0} and
7542 @option{y1} from being included in the field matching decision. An exclusion
7543 band can be used to ignore subtitles, a logo, or other things that may
7544 interfere with the matching. @option{y0} sets the starting scan line and
7545 @option{y1} sets the ending line; all lines in between @option{y0} and
7546 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
7547 @option{y0} and @option{y1} to the same value will disable the feature.
7548 @option{y0} and @option{y1} defaults to @code{0}.
7551 Set the scene change detection threshold as a percentage of maximum change on
7552 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
7553 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
7554 @option{scthresh} is @code{[0.0, 100.0]}.
7556 Default value is @code{12.0}.
7559 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
7560 account the combed scores of matches when deciding what match to use as the
7561 final match. Available values are:
7565 No final matching based on combed scores.
7567 Combed scores are only used when a scene change is detected.
7569 Use combed scores all the time.
7572 Default is @var{sc}.
7575 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
7576 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
7577 Available values are:
7581 No forced calculation.
7583 Force p/c/n calculations.
7585 Force p/c/n/u/b calculations.
7588 Default value is @var{none}.
7591 This is the area combing threshold used for combed frame detection. This
7592 essentially controls how "strong" or "visible" combing must be to be detected.
7593 Larger values mean combing must be more visible and smaller values mean combing
7594 can be less visible or strong and still be detected. Valid settings are from
7595 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
7596 be detected as combed). This is basically a pixel difference value. A good
7597 range is @code{[8, 12]}.
7599 Default value is @code{9}.
7602 Sets whether or not chroma is considered in the combed frame decision. Only
7603 disable this if your source has chroma problems (rainbowing, etc.) that are
7604 causing problems for the combed frame detection with chroma enabled. Actually,
7605 using @option{chroma}=@var{0} is usually more reliable, except for the case
7606 where there is chroma only combing in the source.
7608 Default value is @code{0}.
7612 Respectively set the x-axis and y-axis size of the window used during combed
7613 frame detection. This has to do with the size of the area in which
7614 @option{combpel} pixels are required to be detected as combed for a frame to be
7615 declared combed. See the @option{combpel} parameter description for more info.
7616 Possible values are any number that is a power of 2 starting at 4 and going up
7619 Default value is @code{16}.
7622 The number of combed pixels inside any of the @option{blocky} by
7623 @option{blockx} size blocks on the frame for the frame to be detected as
7624 combed. While @option{cthresh} controls how "visible" the combing must be, this
7625 setting controls "how much" combing there must be in any localized area (a
7626 window defined by the @option{blockx} and @option{blocky} settings) on the
7627 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
7628 which point no frames will ever be detected as combed). This setting is known
7629 as @option{MI} in TFM/VFM vocabulary.
7631 Default value is @code{80}.
7634 @anchor{p/c/n/u/b meaning}
7635 @subsection p/c/n/u/b meaning
7637 @subsubsection p/c/n
7639 We assume the following telecined stream:
7642 Top fields: 1 2 2 3 4
7643 Bottom fields: 1 2 3 4 4
7646 The numbers correspond to the progressive frame the fields relate to. Here, the
7647 first two frames are progressive, the 3rd and 4th are combed, and so on.
7649 When @code{fieldmatch} is configured to run a matching from bottom
7650 (@option{field}=@var{bottom}) this is how this input stream get transformed:
7655 B 1 2 3 4 4 <-- matching reference
7664 As a result of the field matching, we can see that some frames get duplicated.
7665 To perform a complete inverse telecine, you need to rely on a decimation filter
7666 after this operation. See for instance the @ref{decimate} filter.
7668 The same operation now matching from top fields (@option{field}=@var{top})
7673 T 1 2 2 3 4 <-- matching reference
7683 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
7684 basically, they refer to the frame and field of the opposite parity:
7687 @item @var{p} matches the field of the opposite parity in the previous frame
7688 @item @var{c} matches the field of the opposite parity in the current frame
7689 @item @var{n} matches the field of the opposite parity in the next frame
7694 The @var{u} and @var{b} matching are a bit special in the sense that they match
7695 from the opposite parity flag. In the following examples, we assume that we are
7696 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
7697 'x' is placed above and below each matched fields.
7699 With bottom matching (@option{field}=@var{bottom}):
7704 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
7705 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
7713 With top matching (@option{field}=@var{top}):
7718 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
7719 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
7727 @subsection Examples
7729 Simple IVTC of a top field first telecined stream:
7731 fieldmatch=order=tff:combmatch=none, decimate
7734 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
7736 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
7741 Transform the field order of the input video.
7743 It accepts the following parameters:
7748 The output field order. Valid values are @var{tff} for top field first or @var{bff}
7749 for bottom field first.
7752 The default value is @samp{tff}.
7754 The transformation is done by shifting the picture content up or down
7755 by one line, and filling the remaining line with appropriate picture content.
7756 This method is consistent with most broadcast field order converters.
7758 If the input video is not flagged as being interlaced, or it is already
7759 flagged as being of the required output field order, then this filter does
7760 not alter the incoming video.
7762 It is very useful when converting to or from PAL DV material,
7763 which is bottom field first.
7767 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
7770 @section fifo, afifo
7772 Buffer input images and send them when they are requested.
7774 It is mainly useful when auto-inserted by the libavfilter
7777 It does not take parameters.
7781 Find a rectangular object
7783 It accepts the following options:
7787 Filepath of the object image, needs to be in gray8.
7790 Detection threshold, default is 0.5.
7793 Number of mipmaps, default is 3.
7795 @item xmin, ymin, xmax, ymax
7796 Specifies the rectangle in which to search.
7799 @subsection Examples
7803 Generate a representative palette of a given video using @command{ffmpeg}:
7805 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
7811 Cover a rectangular object
7813 It accepts the following options:
7817 Filepath of the optional cover image, needs to be in yuv420.
7822 It accepts the following values:
7825 cover it by the supplied image
7827 cover it by interpolating the surrounding pixels
7830 Default value is @var{blur}.
7833 @subsection Examples
7837 Generate a representative palette of a given video using @command{ffmpeg}:
7839 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
7846 Convert the input video to one of the specified pixel formats.
7847 Libavfilter will try to pick one that is suitable as input to
7850 It accepts the following parameters:
7854 A '|'-separated list of pixel format names, such as
7855 "pix_fmts=yuv420p|monow|rgb24".
7859 @subsection Examples
7863 Convert the input video to the @var{yuv420p} format
7865 format=pix_fmts=yuv420p
7868 Convert the input video to any of the formats in the list
7870 format=pix_fmts=yuv420p|yuv444p|yuv410p
7877 Convert the video to specified constant frame rate by duplicating or dropping
7878 frames as necessary.
7880 It accepts the following parameters:
7884 The desired output frame rate. The default is @code{25}.
7889 Possible values are:
7892 zero round towards 0
7896 round towards -infinity
7898 round towards +infinity
7902 The default is @code{near}.
7905 Assume the first PTS should be the given value, in seconds. This allows for
7906 padding/trimming at the start of stream. By default, no assumption is made
7907 about the first frame's expected PTS, so no padding or trimming is done.
7908 For example, this could be set to 0 to pad the beginning with duplicates of
7909 the first frame if a video stream starts after the audio stream or to trim any
7910 frames with a negative PTS.
7914 Alternatively, the options can be specified as a flat string:
7915 @var{fps}[:@var{round}].
7917 See also the @ref{setpts} filter.
7919 @subsection Examples
7923 A typical usage in order to set the fps to 25:
7929 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
7931 fps=fps=film:round=near
7937 Pack two different video streams into a stereoscopic video, setting proper
7938 metadata on supported codecs. The two views should have the same size and
7939 framerate and processing will stop when the shorter video ends. Please note
7940 that you may conveniently adjust view properties with the @ref{scale} and
7943 It accepts the following parameters:
7947 The desired packing format. Supported values are:
7952 The views are next to each other (default).
7955 The views are on top of each other.
7958 The views are packed by line.
7961 The views are packed by column.
7964 The views are temporally interleaved.
7973 # Convert left and right views into a frame-sequential video
7974 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
7976 # Convert views into a side-by-side video with the same output resolution as the input
7977 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
7982 Change the frame rate by interpolating new video output frames from the source
7985 This filter is not designed to function correctly with interlaced media. If
7986 you wish to change the frame rate of interlaced media then you are required
7987 to deinterlace before this filter and re-interlace after this filter.
7989 A description of the accepted options follows.
7993 Specify the output frames per second. This option can also be specified
7994 as a value alone. The default is @code{50}.
7997 Specify the start of a range where the output frame will be created as a
7998 linear interpolation of two frames. The range is [@code{0}-@code{255}],
7999 the default is @code{15}.
8002 Specify the end of a range where the output frame will be created as a
8003 linear interpolation of two frames. The range is [@code{0}-@code{255}],
8004 the default is @code{240}.
8007 Specify the level at which a scene change is detected as a value between
8008 0 and 100 to indicate a new scene; a low value reflects a low
8009 probability for the current frame to introduce a new scene, while a higher
8010 value means the current frame is more likely to be one.
8011 The default is @code{7}.
8014 Specify flags influencing the filter process.
8016 Available value for @var{flags} is:
8019 @item scene_change_detect, scd
8020 Enable scene change detection using the value of the option @var{scene}.
8021 This flag is enabled by default.
8027 Select one frame every N-th frame.
8029 This filter accepts the following option:
8032 Select frame after every @code{step} frames.
8033 Allowed values are positive integers higher than 0. Default value is @code{1}.
8039 Apply a frei0r effect to the input video.
8041 To enable the compilation of this filter, you need to install the frei0r
8042 header and configure FFmpeg with @code{--enable-frei0r}.
8044 It accepts the following parameters:
8049 The name of the frei0r effect to load. If the environment variable
8050 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
8051 directories specified by the colon-separated list in @env{FREIOR_PATH}.
8052 Otherwise, the standard frei0r paths are searched, in this order:
8053 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
8054 @file{/usr/lib/frei0r-1/}.
8057 A '|'-separated list of parameters to pass to the frei0r effect.
8061 A frei0r effect parameter can be a boolean (its value is either
8062 "y" or "n"), a double, a color (specified as
8063 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
8064 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
8065 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
8066 @var{X} and @var{Y} are floating point numbers) and/or a string.
8068 The number and types of parameters depend on the loaded effect. If an
8069 effect parameter is not specified, the default value is set.
8071 @subsection Examples
8075 Apply the distort0r effect, setting the first two double parameters:
8077 frei0r=filter_name=distort0r:filter_params=0.5|0.01
8081 Apply the colordistance effect, taking a color as the first parameter:
8083 frei0r=colordistance:0.2/0.3/0.4
8084 frei0r=colordistance:violet
8085 frei0r=colordistance:0x112233
8089 Apply the perspective effect, specifying the top left and top right image
8092 frei0r=perspective:0.2/0.2|0.8/0.2
8096 For more information, see
8097 @url{http://frei0r.dyne.org}
8101 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
8103 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
8104 processing filter, one of them is performed once per block, not per pixel.
8105 This allows for much higher speed.
8107 The filter accepts the following options:
8111 Set quality. This option defines the number of levels for averaging. It accepts
8112 an integer in the range 4-5. Default value is @code{4}.
8115 Force a constant quantization parameter. It accepts an integer in range 0-63.
8116 If not set, the filter will use the QP from the video stream (if available).
8119 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
8120 more details but also more artifacts, while higher values make the image smoother
8121 but also blurrier. Default value is @code{0} − PSNR optimal.
8124 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8125 option may cause flicker since the B-Frames have often larger QP. Default is
8126 @code{0} (not enabled).
8132 The filter accepts the following options:
8136 Set the luminance expression.
8138 Set the chrominance blue expression.
8140 Set the chrominance red expression.
8142 Set the alpha expression.
8144 Set the red expression.
8146 Set the green expression.
8148 Set the blue expression.
8151 The colorspace is selected according to the specified options. If one
8152 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
8153 options is specified, the filter will automatically select a YCbCr
8154 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
8155 @option{blue_expr} options is specified, it will select an RGB
8158 If one of the chrominance expression is not defined, it falls back on the other
8159 one. If no alpha expression is specified it will evaluate to opaque value.
8160 If none of chrominance expressions are specified, they will evaluate
8161 to the luminance expression.
8163 The expressions can use the following variables and functions:
8167 The sequential number of the filtered frame, starting from @code{0}.
8171 The coordinates of the current sample.
8175 The width and height of the image.
8179 Width and height scale depending on the currently filtered plane. It is the
8180 ratio between the corresponding luma plane number of pixels and the current
8181 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
8182 @code{0.5,0.5} for chroma planes.
8185 Time of the current frame, expressed in seconds.
8188 Return the value of the pixel at location (@var{x},@var{y}) of the current
8192 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
8196 Return the value of the pixel at location (@var{x},@var{y}) of the
8197 blue-difference chroma plane. Return 0 if there is no such plane.
8200 Return the value of the pixel at location (@var{x},@var{y}) of the
8201 red-difference chroma plane. Return 0 if there is no such plane.
8206 Return the value of the pixel at location (@var{x},@var{y}) of the
8207 red/green/blue component. Return 0 if there is no such component.
8210 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
8211 plane. Return 0 if there is no such plane.
8214 For functions, if @var{x} and @var{y} are outside the area, the value will be
8215 automatically clipped to the closer edge.
8217 @subsection Examples
8221 Flip the image horizontally:
8227 Generate a bidimensional sine wave, with angle @code{PI/3} and a
8228 wavelength of 100 pixels:
8230 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
8234 Generate a fancy enigmatic moving light:
8236 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
8240 Generate a quick emboss effect:
8242 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
8246 Modify RGB components depending on pixel position:
8248 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
8252 Create a radial gradient that is the same size as the input (also see
8253 the @ref{vignette} filter):
8255 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
8261 Fix the banding artifacts that are sometimes introduced into nearly flat
8262 regions by truncation to 8bit color depth.
8263 Interpolate the gradients that should go where the bands are, and
8266 It is designed for playback only. Do not use it prior to
8267 lossy compression, because compression tends to lose the dither and
8268 bring back the bands.
8270 It accepts the following parameters:
8275 The maximum amount by which the filter will change any one pixel. This is also
8276 the threshold for detecting nearly flat regions. Acceptable values range from
8277 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
8281 The neighborhood to fit the gradient to. A larger radius makes for smoother
8282 gradients, but also prevents the filter from modifying the pixels near detailed
8283 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
8284 values will be clipped to the valid range.
8288 Alternatively, the options can be specified as a flat string:
8289 @var{strength}[:@var{radius}]
8291 @subsection Examples
8295 Apply the filter with a @code{3.5} strength and radius of @code{8}:
8301 Specify radius, omitting the strength (which will fall-back to the default
8312 Apply a Hald CLUT to a video stream.
8314 First input is the video stream to process, and second one is the Hald CLUT.
8315 The Hald CLUT input can be a simple picture or a complete video stream.
8317 The filter accepts the following options:
8321 Force termination when the shortest input terminates. Default is @code{0}.
8323 Continue applying the last CLUT after the end of the stream. A value of
8324 @code{0} disable the filter after the last frame of the CLUT is reached.
8325 Default is @code{1}.
8328 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
8329 filters share the same internals).
8331 More information about the Hald CLUT can be found on Eskil Steenberg's website
8332 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
8334 @subsection Workflow examples
8336 @subsubsection Hald CLUT video stream
8338 Generate an identity Hald CLUT stream altered with various effects:
8340 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
8343 Note: make sure you use a lossless codec.
8345 Then use it with @code{haldclut} to apply it on some random stream:
8347 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
8350 The Hald CLUT will be applied to the 10 first seconds (duration of
8351 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
8352 to the remaining frames of the @code{mandelbrot} stream.
8354 @subsubsection Hald CLUT with preview
8356 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
8357 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
8358 biggest possible square starting at the top left of the picture. The remaining
8359 padding pixels (bottom or right) will be ignored. This area can be used to add
8360 a preview of the Hald CLUT.
8362 Typically, the following generated Hald CLUT will be supported by the
8363 @code{haldclut} filter:
8366 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
8367 pad=iw+320 [padded_clut];
8368 smptebars=s=320x256, split [a][b];
8369 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
8370 [main][b] overlay=W-320" -frames:v 1 clut.png
8373 It contains the original and a preview of the effect of the CLUT: SMPTE color
8374 bars are displayed on the right-top, and below the same color bars processed by
8377 Then, the effect of this Hald CLUT can be visualized with:
8379 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
8384 Decodes high definition audio cd data. 16-Bit PCM stream containing hdcd flags
8385 is converted to 20-bit PCM stream.
8389 Flip the input video horizontally.
8391 For example, to horizontally flip the input video with @command{ffmpeg}:
8393 ffmpeg -i in.avi -vf "hflip" out.avi
8397 This filter applies a global color histogram equalization on a
8400 It can be used to correct video that has a compressed range of pixel
8401 intensities. The filter redistributes the pixel intensities to
8402 equalize their distribution across the intensity range. It may be
8403 viewed as an "automatically adjusting contrast filter". This filter is
8404 useful only for correcting degraded or poorly captured source
8407 The filter accepts the following options:
8411 Determine the amount of equalization to be applied. As the strength
8412 is reduced, the distribution of pixel intensities more-and-more
8413 approaches that of the input frame. The value must be a float number
8414 in the range [0,1] and defaults to 0.200.
8417 Set the maximum intensity that can generated and scale the output
8418 values appropriately. The strength should be set as desired and then
8419 the intensity can be limited if needed to avoid washing-out. The value
8420 must be a float number in the range [0,1] and defaults to 0.210.
8423 Set the antibanding level. If enabled the filter will randomly vary
8424 the luminance of output pixels by a small amount to avoid banding of
8425 the histogram. Possible values are @code{none}, @code{weak} or
8426 @code{strong}. It defaults to @code{none}.
8431 Compute and draw a color distribution histogram for the input video.
8433 The computed histogram is a representation of the color component
8434 distribution in an image.
8436 Standard histogram displays the color components distribution in an image.
8437 Displays color graph for each color component. Shows distribution of
8438 the Y, U, V, A or R, G, B components, depending on input format, in the
8439 current frame. Below each graph a color component scale meter is shown.
8441 The filter accepts the following options:
8445 Set height of level. Default value is @code{200}.
8446 Allowed range is [50, 2048].
8449 Set height of color scale. Default value is @code{12}.
8450 Allowed range is [0, 40].
8454 It accepts the following values:
8457 Per color component graphs are placed below each other.
8460 Presents information identical to that in the @code{parade}, except
8461 that the graphs representing color components are superimposed directly
8464 Default is @code{parade}.
8467 Set mode. Can be either @code{linear}, or @code{logarithmic}.
8468 Default is @code{linear}.
8471 Set what color components to display.
8472 Default is @code{7}.
8475 @subsection Examples
8480 Calculate and draw histogram:
8482 ffplay -i input -vf histogram
8490 This is a high precision/quality 3d denoise filter. It aims to reduce
8491 image noise, producing smooth images and making still images really
8492 still. It should enhance compressibility.
8494 It accepts the following optional parameters:
8498 A non-negative floating point number which specifies spatial luma strength.
8501 @item chroma_spatial
8502 A non-negative floating point number which specifies spatial chroma strength.
8503 It defaults to 3.0*@var{luma_spatial}/4.0.
8506 A floating point number which specifies luma temporal strength. It defaults to
8507 6.0*@var{luma_spatial}/4.0.
8510 A floating point number which specifies chroma temporal strength. It defaults to
8511 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
8514 @anchor{hwupload_cuda}
8515 @section hwupload_cuda
8517 Upload system memory frames to a CUDA device.
8519 It accepts the following optional parameters:
8523 The number of the CUDA device to use
8528 Apply a high-quality magnification filter designed for pixel art. This filter
8529 was originally created by Maxim Stepin.
8531 It accepts the following option:
8535 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
8536 @code{hq3x} and @code{4} for @code{hq4x}.
8537 Default is @code{3}.
8541 Stack input videos horizontally.
8543 All streams must be of same pixel format and of same height.
8545 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
8546 to create same output.
8548 The filter accept the following option:
8552 Set number of input streams. Default is 2.
8555 If set to 1, force the output to terminate when the shortest input
8556 terminates. Default value is 0.
8561 Modify the hue and/or the saturation of the input.
8563 It accepts the following parameters:
8567 Specify the hue angle as a number of degrees. It accepts an expression,
8568 and defaults to "0".
8571 Specify the saturation in the [-10,10] range. It accepts an expression and
8575 Specify the hue angle as a number of radians. It accepts an
8576 expression, and defaults to "0".
8579 Specify the brightness in the [-10,10] range. It accepts an expression and
8583 @option{h} and @option{H} are mutually exclusive, and can't be
8584 specified at the same time.
8586 The @option{b}, @option{h}, @option{H} and @option{s} option values are
8587 expressions containing the following constants:
8591 frame count of the input frame starting from 0
8594 presentation timestamp of the input frame expressed in time base units
8597 frame rate of the input video, NAN if the input frame rate is unknown
8600 timestamp expressed in seconds, NAN if the input timestamp is unknown
8603 time base of the input video
8606 @subsection Examples
8610 Set the hue to 90 degrees and the saturation to 1.0:
8616 Same command but expressing the hue in radians:
8622 Rotate hue and make the saturation swing between 0
8623 and 2 over a period of 1 second:
8625 hue="H=2*PI*t: s=sin(2*PI*t)+1"
8629 Apply a 3 seconds saturation fade-in effect starting at 0:
8634 The general fade-in expression can be written as:
8636 hue="s=min(0\, max((t-START)/DURATION\, 1))"
8640 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
8642 hue="s=max(0\, min(1\, (8-t)/3))"
8645 The general fade-out expression can be written as:
8647 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
8652 @subsection Commands
8654 This filter supports the following commands:
8660 Modify the hue and/or the saturation and/or brightness of the input video.
8661 The command accepts the same syntax of the corresponding option.
8663 If the specified expression is not valid, it is kept at its current
8669 Detect video interlacing type.
8671 This filter tries to detect if the input frames as interlaced, progressive,
8672 top or bottom field first. It will also try and detect fields that are
8673 repeated between adjacent frames (a sign of telecine).
8675 Single frame detection considers only immediately adjacent frames when classifying each frame.
8676 Multiple frame detection incorporates the classification history of previous frames.
8678 The filter will log these metadata values:
8681 @item single.current_frame
8682 Detected type of current frame using single-frame detection. One of:
8683 ``tff'' (top field first), ``bff'' (bottom field first),
8684 ``progressive'', or ``undetermined''
8687 Cumulative number of frames detected as top field first using single-frame detection.
8690 Cumulative number of frames detected as top field first using multiple-frame detection.
8693 Cumulative number of frames detected as bottom field first using single-frame detection.
8695 @item multiple.current_frame
8696 Detected type of current frame using multiple-frame detection. One of:
8697 ``tff'' (top field first), ``bff'' (bottom field first),
8698 ``progressive'', or ``undetermined''
8701 Cumulative number of frames detected as bottom field first using multiple-frame detection.
8703 @item single.progressive
8704 Cumulative number of frames detected as progressive using single-frame detection.
8706 @item multiple.progressive
8707 Cumulative number of frames detected as progressive using multiple-frame detection.
8709 @item single.undetermined
8710 Cumulative number of frames that could not be classified using single-frame detection.
8712 @item multiple.undetermined
8713 Cumulative number of frames that could not be classified using multiple-frame detection.
8715 @item repeated.current_frame
8716 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
8718 @item repeated.neither
8719 Cumulative number of frames with no repeated field.
8722 Cumulative number of frames with the top field repeated from the previous frame's top field.
8724 @item repeated.bottom
8725 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
8728 The filter accepts the following options:
8732 Set interlacing threshold.
8734 Set progressive threshold.
8736 Threshold for repeated field detection.
8738 Number of frames after which a given frame's contribution to the
8739 statistics is halved (i.e., it contributes only 0.5 to it's
8740 classification). The default of 0 means that all frames seen are given
8741 full weight of 1.0 forever.
8742 @item analyze_interlaced_flag
8743 When this is not 0 then idet will use the specified number of frames to determine
8744 if the interlaced flag is accurate, it will not count undetermined frames.
8745 If the flag is found to be accurate it will be used without any further
8746 computations, if it is found to be inaccurate it will be cleared without any
8747 further computations. This allows inserting the idet filter as a low computational
8748 method to clean up the interlaced flag
8753 Deinterleave or interleave fields.
8755 This filter allows one to process interlaced images fields without
8756 deinterlacing them. Deinterleaving splits the input frame into 2
8757 fields (so called half pictures). Odd lines are moved to the top
8758 half of the output image, even lines to the bottom half.
8759 You can process (filter) them independently and then re-interleave them.
8761 The filter accepts the following options:
8765 @item chroma_mode, c
8767 Available values for @var{luma_mode}, @var{chroma_mode} and
8768 @var{alpha_mode} are:
8774 @item deinterleave, d
8775 Deinterleave fields, placing one above the other.
8778 Interleave fields. Reverse the effect of deinterleaving.
8780 Default value is @code{none}.
8783 @item chroma_swap, cs
8784 @item alpha_swap, as
8785 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
8790 Apply inflate effect to the video.
8792 This filter replaces the pixel by the local(3x3) average by taking into account
8793 only values higher than the pixel.
8795 It accepts the following options:
8802 Limit the maximum change for each plane, default is 65535.
8803 If 0, plane will remain unchanged.
8808 Simple interlacing filter from progressive contents. This interleaves upper (or
8809 lower) lines from odd frames with lower (or upper) lines from even frames,
8810 halving the frame rate and preserving image height.
8813 Original Original New Frame
8814 Frame 'j' Frame 'j+1' (tff)
8815 ========== =========== ==================
8816 Line 0 --------------------> Frame 'j' Line 0
8817 Line 1 Line 1 ----> Frame 'j+1' Line 1
8818 Line 2 ---------------------> Frame 'j' Line 2
8819 Line 3 Line 3 ----> Frame 'j+1' Line 3
8821 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
8824 It accepts the following optional parameters:
8828 This determines whether the interlaced frame is taken from the even
8829 (tff - default) or odd (bff) lines of the progressive frame.
8832 Enable (default) or disable the vertical lowpass filter to avoid twitter
8833 interlacing and reduce moire patterns.
8838 Deinterlace input video by applying Donald Graft's adaptive kernel
8839 deinterling. Work on interlaced parts of a video to produce
8842 The description of the accepted parameters follows.
8846 Set the threshold which affects the filter's tolerance when
8847 determining if a pixel line must be processed. It must be an integer
8848 in the range [0,255] and defaults to 10. A value of 0 will result in
8849 applying the process on every pixels.
8852 Paint pixels exceeding the threshold value to white if set to 1.
8856 Set the fields order. Swap fields if set to 1, leave fields alone if
8860 Enable additional sharpening if set to 1. Default is 0.
8863 Enable twoway sharpening if set to 1. Default is 0.
8866 @subsection Examples
8870 Apply default values:
8872 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
8876 Enable additional sharpening:
8882 Paint processed pixels in white:
8888 @section lenscorrection
8890 Correct radial lens distortion
8892 This filter can be used to correct for radial distortion as can result from the use
8893 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
8894 one can use tools available for example as part of opencv or simply trial-and-error.
8895 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
8896 and extract the k1 and k2 coefficients from the resulting matrix.
8898 Note that effectively the same filter is available in the open-source tools Krita and
8899 Digikam from the KDE project.
8901 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
8902 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
8903 brightness distribution, so you may want to use both filters together in certain
8904 cases, though you will have to take care of ordering, i.e. whether vignetting should
8905 be applied before or after lens correction.
8909 The filter accepts the following options:
8913 Relative x-coordinate of the focal point of the image, and thereby the center of the
8914 distortion. This value has a range [0,1] and is expressed as fractions of the image
8917 Relative y-coordinate of the focal point of the image, and thereby the center of the
8918 distortion. This value has a range [0,1] and is expressed as fractions of the image
8921 Coefficient of the quadratic correction term. 0.5 means no correction.
8923 Coefficient of the double quadratic correction term. 0.5 means no correction.
8926 The formula that generates the correction is:
8928 @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)
8930 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
8931 distances from the focal point in the source and target images, respectively.
8933 @section loop, aloop
8935 Loop video frames or audio samples.
8937 Those filters accepts the following options:
8941 Set the number of loops.
8944 Set maximal size in number of frames for @code{loop} filter or maximal number
8945 of samples in case of @code{aloop} filter.
8948 Set first frame of loop for @code{loop} filter or first sample of loop in case
8949 of @code{aloop} filter.
8955 Apply a 3D LUT to an input video.
8957 The filter accepts the following options:
8961 Set the 3D LUT file name.
8963 Currently supported formats:
8975 Select interpolation mode.
8977 Available values are:
8981 Use values from the nearest defined point.
8983 Interpolate values using the 8 points defining a cube.
8985 Interpolate values using a tetrahedron.
8989 @section lut, lutrgb, lutyuv
8991 Compute a look-up table for binding each pixel component input value
8992 to an output value, and apply it to the input video.
8994 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
8995 to an RGB input video.
8997 These filters accept the following parameters:
9000 set first pixel component expression
9002 set second pixel component expression
9004 set third pixel component expression
9006 set fourth pixel component expression, corresponds to the alpha component
9009 set red component expression
9011 set green component expression
9013 set blue component expression
9015 alpha component expression
9018 set Y/luminance component expression
9020 set U/Cb component expression
9022 set V/Cr component expression
9025 Each of them specifies the expression to use for computing the lookup table for
9026 the corresponding pixel component values.
9028 The exact component associated to each of the @var{c*} options depends on the
9031 The @var{lut} filter requires either YUV or RGB pixel formats in input,
9032 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
9034 The expressions can contain the following constants and functions:
9039 The input width and height.
9042 The input value for the pixel component.
9045 The input value, clipped to the @var{minval}-@var{maxval} range.
9048 The maximum value for the pixel component.
9051 The minimum value for the pixel component.
9054 The negated value for the pixel component value, clipped to the
9055 @var{minval}-@var{maxval} range; it corresponds to the expression
9056 "maxval-clipval+minval".
9059 The computed value in @var{val}, clipped to the
9060 @var{minval}-@var{maxval} range.
9062 @item gammaval(gamma)
9063 The computed gamma correction value of the pixel component value,
9064 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
9066 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
9070 All expressions default to "val".
9072 @subsection Examples
9078 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
9079 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
9082 The above is the same as:
9084 lutrgb="r=negval:g=negval:b=negval"
9085 lutyuv="y=negval:u=negval:v=negval"
9095 Remove chroma components, turning the video into a graytone image:
9097 lutyuv="u=128:v=128"
9101 Apply a luma burning effect:
9107 Remove green and blue components:
9113 Set a constant alpha channel value on input:
9115 format=rgba,lutrgb=a="maxval-minval/2"
9119 Correct luminance gamma by a factor of 0.5:
9121 lutyuv=y=gammaval(0.5)
9125 Discard least significant bits of luma:
9127 lutyuv=y='bitand(val, 128+64+32)'
9131 @section maskedmerge
9133 Merge the first input stream with the second input stream using per pixel
9134 weights in the third input stream.
9136 A value of 0 in the third stream pixel component means that pixel component
9137 from first stream is returned unchanged, while maximum value (eg. 255 for
9138 8-bit videos) means that pixel component from second stream is returned
9139 unchanged. Intermediate values define the amount of merging between both
9140 input stream's pixel components.
9142 This filter accepts the following options:
9145 Set which planes will be processed as bitmap, unprocessed planes will be
9146 copied from first stream.
9147 By default value 0xf, all planes will be processed.
9152 Apply motion-compensation deinterlacing.
9154 It needs one field per frame as input and must thus be used together
9155 with yadif=1/3 or equivalent.
9157 This filter accepts the following options:
9160 Set the deinterlacing mode.
9162 It accepts one of the following values:
9167 use iterative motion estimation
9169 like @samp{slow}, but use multiple reference frames.
9171 Default value is @samp{fast}.
9174 Set the picture field parity assumed for the input video. It must be
9175 one of the following values:
9179 assume top field first
9181 assume bottom field first
9184 Default value is @samp{bff}.
9187 Set per-block quantization parameter (QP) used by the internal
9190 Higher values should result in a smoother motion vector field but less
9191 optimal individual vectors. Default value is 1.
9194 @section mergeplanes
9196 Merge color channel components from several video streams.
9198 The filter accepts up to 4 input streams, and merge selected input
9199 planes to the output video.
9201 This filter accepts the following options:
9204 Set input to output plane mapping. Default is @code{0}.
9206 The mappings is specified as a bitmap. It should be specified as a
9207 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
9208 mapping for the first plane of the output stream. 'A' sets the number of
9209 the input stream to use (from 0 to 3), and 'a' the plane number of the
9210 corresponding input to use (from 0 to 3). The rest of the mappings is
9211 similar, 'Bb' describes the mapping for the output stream second
9212 plane, 'Cc' describes the mapping for the output stream third plane and
9213 'Dd' describes the mapping for the output stream fourth plane.
9216 Set output pixel format. Default is @code{yuva444p}.
9219 @subsection Examples
9223 Merge three gray video streams of same width and height into single video stream:
9225 [a0][a1][a2]mergeplanes=0x001020:yuv444p
9229 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
9231 [a0][a1]mergeplanes=0x00010210:yuva444p
9235 Swap Y and A plane in yuva444p stream:
9237 format=yuva444p,mergeplanes=0x03010200:yuva444p
9241 Swap U and V plane in yuv420p stream:
9243 format=yuv420p,mergeplanes=0x000201:yuv420p
9247 Cast a rgb24 clip to yuv444p:
9249 format=rgb24,mergeplanes=0x000102:yuv444p
9253 @section metadata, ametadata
9255 Manipulate frame metadata.
9257 This filter accepts the following options:
9261 Set mode of operation of the filter.
9263 Can be one of the following:
9267 If both @code{value} and @code{key} is set, select frames
9268 which have such metadata. If only @code{key} is set, select
9269 every frame that has such key in metadata.
9272 Add new metadata @code{key} and @code{value}. If key is already available
9276 Modify value of already present key.
9279 If @code{value} is set, delete only keys that have such value.
9280 Otherwise, delete key.
9283 Print key and its value if metadata was found. If @code{key} is not set print all
9284 metadata values available in frame.
9288 Set key used with all modes. Must be set for all modes except @code{print}.
9291 Set metadata value which will be used. This option is mandatory for
9292 @code{modify} and @code{add} mode.
9295 Which function to use when comparing metadata value and @code{value}.
9297 Can be one of following:
9301 Values are interpreted as strings, returns true if metadata value is same as @code{value}.
9304 Values are interpreted as strings, returns true if metadata value starts with
9305 the @code{value} option string.
9308 Values are interpreted as floats, returns true if metadata value is less than @code{value}.
9311 Values are interpreted as floats, returns true if @code{value} is equal with metadata value.
9314 Values are interpreted as floats, returns true if metadata value is greater than @code{value}.
9317 Values are interpreted as floats, returns true if expression from option @code{expr}
9322 Set expression which is used when @code{function} is set to @code{expr}.
9323 The expression is evaluated through the eval API and can contain the following
9328 Float representation of @code{value} from metadata key.
9331 Float representation of @code{value} as supplied by user in @code{value} option.
9335 If specified in @code{print} mode, output is written to the named file. When
9336 filename equals "-" data is written to standard output.
9337 If @code{file} option is not set, output is written to the log with AV_LOG_INFO
9341 @subsection Examples
9345 Print all metadata values for frames with key @code{lavfi.singnalstats.YDIF} with values
9349 signalstats,metadata=print:key=lavfi.signalstats.YDIF:value=0:function=expr:expr='between(VALUE1,0,1)'
9354 Drop frames that do not differ greatly from the previous frame in
9355 order to reduce frame rate.
9357 The main use of this filter is for very-low-bitrate encoding
9358 (e.g. streaming over dialup modem), but it could in theory be used for
9359 fixing movies that were inverse-telecined incorrectly.
9361 A description of the accepted options follows.
9365 Set the maximum number of consecutive frames which can be dropped (if
9366 positive), or the minimum interval between dropped frames (if
9367 negative). If the value is 0, the frame is dropped unregarding the
9368 number of previous sequentially dropped frames.
9375 Set the dropping threshold values.
9377 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
9378 represent actual pixel value differences, so a threshold of 64
9379 corresponds to 1 unit of difference for each pixel, or the same spread
9380 out differently over the block.
9382 A frame is a candidate for dropping if no 8x8 blocks differ by more
9383 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
9384 meaning the whole image) differ by more than a threshold of @option{lo}.
9386 Default value for @option{hi} is 64*12, default value for @option{lo} is
9387 64*5, and default value for @option{frac} is 0.33.
9395 It accepts an integer in input; if non-zero it negates the
9396 alpha component (if available). The default value in input is 0.
9400 Deinterlace video using neural network edge directed interpolation.
9402 This filter accepts the following options:
9406 Mandatory option, without binary file filter can not work.
9407 Currently file can be found here:
9408 https://github.com/dubhater/vapoursynth-nnedi3/blob/master/src/nnedi3_weights.bin
9411 Set which frames to deinterlace, by default it is @code{all}.
9412 Can be @code{all} or @code{interlaced}.
9415 Set mode of operation.
9417 Can be one of the following:
9421 Use frame flags, both fields.
9423 Use frame flags, single field.
9427 Use bottom field only.
9429 Use both fields, top first.
9431 Use both fields, bottom first.
9435 Set which planes to process, by default filter process all frames.
9438 Set size of local neighborhood around each pixel, used by the predictor neural
9441 Can be one of the following:
9454 Set the number of neurons in predicctor neural network.
9455 Can be one of the following:
9466 Controls the number of different neural network predictions that are blended
9467 together to compute the final output value. Can be @code{fast}, default or
9471 Set which set of weights to use in the predictor.
9472 Can be one of the following:
9476 weights trained to minimize absolute error
9478 weights trained to minimize squared error
9482 Controls whether or not the prescreener neural network is used to decide
9483 which pixels should be processed by the predictor neural network and which
9484 can be handled by simple cubic interpolation.
9485 The prescreener is trained to know whether cubic interpolation will be
9486 sufficient for a pixel or whether it should be predicted by the predictor nn.
9487 The computational complexity of the prescreener nn is much less than that of
9488 the predictor nn. Since most pixels can be handled by cubic interpolation,
9489 using the prescreener generally results in much faster processing.
9490 The prescreener is pretty accurate, so the difference between using it and not
9491 using it is almost always unnoticeable.
9493 Can be one of the following:
9501 Default is @code{new}.
9504 Set various debugging flags.
9509 Force libavfilter not to use any of the specified pixel formats for the
9510 input to the next filter.
9512 It accepts the following parameters:
9516 A '|'-separated list of pixel format names, such as
9517 apix_fmts=yuv420p|monow|rgb24".
9521 @subsection Examples
9525 Force libavfilter to use a format different from @var{yuv420p} for the
9526 input to the vflip filter:
9528 noformat=pix_fmts=yuv420p,vflip
9532 Convert the input video to any of the formats not contained in the list:
9534 noformat=yuv420p|yuv444p|yuv410p
9540 Add noise on video input frame.
9542 The filter accepts the following options:
9550 Set noise seed for specific pixel component or all pixel components in case
9551 of @var{all_seed}. Default value is @code{123457}.
9553 @item all_strength, alls
9554 @item c0_strength, c0s
9555 @item c1_strength, c1s
9556 @item c2_strength, c2s
9557 @item c3_strength, c3s
9558 Set noise strength for specific pixel component or all pixel components in case
9559 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
9561 @item all_flags, allf
9566 Set pixel component flags or set flags for all components if @var{all_flags}.
9567 Available values for component flags are:
9570 averaged temporal noise (smoother)
9572 mix random noise with a (semi)regular pattern
9574 temporal noise (noise pattern changes between frames)
9576 uniform noise (gaussian otherwise)
9580 @subsection Examples
9582 Add temporal and uniform noise to input video:
9584 noise=alls=20:allf=t+u
9589 Pass the video source unchanged to the output.
9592 Optical Character Recognition
9594 This filter uses Tesseract for optical character recognition.
9596 It accepts the following options:
9600 Set datapath to tesseract data. Default is to use whatever was
9601 set at installation.
9604 Set language, default is "eng".
9607 Set character whitelist.
9610 Set character blacklist.
9613 The filter exports recognized text as the frame metadata @code{lavfi.ocr.text}.
9617 Apply a video transform using libopencv.
9619 To enable this filter, install the libopencv library and headers and
9620 configure FFmpeg with @code{--enable-libopencv}.
9622 It accepts the following parameters:
9627 The name of the libopencv filter to apply.
9630 The parameters to pass to the libopencv filter. If not specified, the default
9635 Refer to the official libopencv documentation for more precise
9637 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
9639 Several libopencv filters are supported; see the following subsections.
9644 Dilate an image by using a specific structuring element.
9645 It corresponds to the libopencv function @code{cvDilate}.
9647 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
9649 @var{struct_el} represents a structuring element, and has the syntax:
9650 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
9652 @var{cols} and @var{rows} represent the number of columns and rows of
9653 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
9654 point, and @var{shape} the shape for the structuring element. @var{shape}
9655 must be "rect", "cross", "ellipse", or "custom".
9657 If the value for @var{shape} is "custom", it must be followed by a
9658 string of the form "=@var{filename}". The file with name
9659 @var{filename} is assumed to represent a binary image, with each
9660 printable character corresponding to a bright pixel. When a custom
9661 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
9662 or columns and rows of the read file are assumed instead.
9664 The default value for @var{struct_el} is "3x3+0x0/rect".
9666 @var{nb_iterations} specifies the number of times the transform is
9667 applied to the image, and defaults to 1.
9671 # Use the default values
9674 # Dilate using a structuring element with a 5x5 cross, iterating two times
9675 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
9677 # Read the shape from the file diamond.shape, iterating two times.
9678 # The file diamond.shape may contain a pattern of characters like this
9684 # The specified columns and rows are ignored
9685 # but the anchor point coordinates are not
9686 ocv=dilate:0x0+2x2/custom=diamond.shape|2
9691 Erode an image by using a specific structuring element.
9692 It corresponds to the libopencv function @code{cvErode}.
9694 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
9695 with the same syntax and semantics as the @ref{dilate} filter.
9699 Smooth the input video.
9701 The filter takes the following parameters:
9702 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
9704 @var{type} is the type of smooth filter to apply, and must be one of
9705 the following values: "blur", "blur_no_scale", "median", "gaussian",
9706 or "bilateral". The default value is "gaussian".
9708 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
9709 depend on the smooth type. @var{param1} and
9710 @var{param2} accept integer positive values or 0. @var{param3} and
9711 @var{param4} accept floating point values.
9713 The default value for @var{param1} is 3. The default value for the
9714 other parameters is 0.
9716 These parameters correspond to the parameters assigned to the
9717 libopencv function @code{cvSmooth}.
9722 Overlay one video on top of another.
9724 It takes two inputs and has one output. The first input is the "main"
9725 video on which the second input is overlaid.
9727 It accepts the following parameters:
9729 A description of the accepted options follows.
9734 Set the expression for the x and y coordinates of the overlaid video
9735 on the main video. Default value is "0" for both expressions. In case
9736 the expression is invalid, it is set to a huge value (meaning that the
9737 overlay will not be displayed within the output visible area).
9740 The action to take when EOF is encountered on the secondary input; it accepts
9741 one of the following values:
9745 Repeat the last frame (the default).
9749 Pass the main input through.
9753 Set when the expressions for @option{x}, and @option{y} are evaluated.
9755 It accepts the following values:
9758 only evaluate expressions once during the filter initialization or
9759 when a command is processed
9762 evaluate expressions for each incoming frame
9765 Default value is @samp{frame}.
9768 If set to 1, force the output to terminate when the shortest input
9769 terminates. Default value is 0.
9772 Set the format for the output video.
9774 It accepts the following values:
9789 Default value is @samp{yuv420}.
9791 @item rgb @emph{(deprecated)}
9792 If set to 1, force the filter to accept inputs in the RGB
9793 color space. Default value is 0. This option is deprecated, use
9794 @option{format} instead.
9797 If set to 1, force the filter to draw the last overlay frame over the
9798 main input until the end of the stream. A value of 0 disables this
9799 behavior. Default value is 1.
9802 The @option{x}, and @option{y} expressions can contain the following
9808 The main input width and height.
9812 The overlay input width and height.
9816 The computed values for @var{x} and @var{y}. They are evaluated for
9821 horizontal and vertical chroma subsample values of the output
9822 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
9826 the number of input frame, starting from 0
9829 the position in the file of the input frame, NAN if unknown
9832 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
9836 Note that the @var{n}, @var{pos}, @var{t} variables are available only
9837 when evaluation is done @emph{per frame}, and will evaluate to NAN
9838 when @option{eval} is set to @samp{init}.
9840 Be aware that frames are taken from each input video in timestamp
9841 order, hence, if their initial timestamps differ, it is a good idea
9842 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
9843 have them begin in the same zero timestamp, as the example for
9844 the @var{movie} filter does.
9846 You can chain together more overlays but you should test the
9847 efficiency of such approach.
9849 @subsection Commands
9851 This filter supports the following commands:
9855 Modify the x and y of the overlay input.
9856 The command accepts the same syntax of the corresponding option.
9858 If the specified expression is not valid, it is kept at its current
9862 @subsection Examples
9866 Draw the overlay at 10 pixels from the bottom right corner of the main
9869 overlay=main_w-overlay_w-10:main_h-overlay_h-10
9872 Using named options the example above becomes:
9874 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
9878 Insert a transparent PNG logo in the bottom left corner of the input,
9879 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
9881 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
9885 Insert 2 different transparent PNG logos (second logo on bottom
9886 right corner) using the @command{ffmpeg} tool:
9888 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
9892 Add a transparent color layer on top of the main video; @code{WxH}
9893 must specify the size of the main input to the overlay filter:
9895 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
9899 Play an original video and a filtered version (here with the deshake
9900 filter) side by side using the @command{ffplay} tool:
9902 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
9905 The above command is the same as:
9907 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
9911 Make a sliding overlay appearing from the left to the right top part of the
9912 screen starting since time 2:
9914 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
9918 Compose output by putting two input videos side to side:
9920 ffmpeg -i left.avi -i right.avi -filter_complex "
9921 nullsrc=size=200x100 [background];
9922 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
9923 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
9924 [background][left] overlay=shortest=1 [background+left];
9925 [background+left][right] overlay=shortest=1:x=100 [left+right]
9930 Mask 10-20 seconds of a video by applying the delogo filter to a section
9932 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
9933 -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]'
9938 Chain several overlays in cascade:
9940 nullsrc=s=200x200 [bg];
9941 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
9942 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
9943 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
9944 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
9945 [in3] null, [mid2] overlay=100:100 [out0]
9952 Apply Overcomplete Wavelet denoiser.
9954 The filter accepts the following options:
9960 Larger depth values will denoise lower frequency components more, but
9961 slow down filtering.
9963 Must be an int in the range 8-16, default is @code{8}.
9965 @item luma_strength, ls
9968 Must be a double value in the range 0-1000, default is @code{1.0}.
9970 @item chroma_strength, cs
9971 Set chroma strength.
9973 Must be a double value in the range 0-1000, default is @code{1.0}.
9979 Add paddings to the input image, and place the original input at the
9980 provided @var{x}, @var{y} coordinates.
9982 It accepts the following parameters:
9987 Specify an expression for the size of the output image with the
9988 paddings added. If the value for @var{width} or @var{height} is 0, the
9989 corresponding input size is used for the output.
9991 The @var{width} expression can reference the value set by the
9992 @var{height} expression, and vice versa.
9994 The default value of @var{width} and @var{height} is 0.
9998 Specify the offsets to place the input image at within the padded area,
9999 with respect to the top/left border of the output image.
10001 The @var{x} expression can reference the value set by the @var{y}
10002 expression, and vice versa.
10004 The default value of @var{x} and @var{y} is 0.
10007 Specify the color of the padded area. For the syntax of this option,
10008 check the "Color" section in the ffmpeg-utils manual.
10010 The default value of @var{color} is "black".
10013 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
10014 options are expressions containing the following constants:
10019 The input video width and height.
10023 These are the same as @var{in_w} and @var{in_h}.
10027 The output width and height (the size of the padded area), as
10028 specified by the @var{width} and @var{height} expressions.
10032 These are the same as @var{out_w} and @var{out_h}.
10036 The x and y offsets as specified by the @var{x} and @var{y}
10037 expressions, or NAN if not yet specified.
10040 same as @var{iw} / @var{ih}
10043 input sample aspect ratio
10046 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
10050 The horizontal and vertical chroma subsample values. For example for the
10051 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
10054 @subsection Examples
10058 Add paddings with the color "violet" to the input video. The output video
10059 size is 640x480, and the top-left corner of the input video is placed at
10062 pad=640:480:0:40:violet
10065 The example above is equivalent to the following command:
10067 pad=width=640:height=480:x=0:y=40:color=violet
10071 Pad the input to get an output with dimensions increased by 3/2,
10072 and put the input video at the center of the padded area:
10074 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
10078 Pad the input to get a squared output with size equal to the maximum
10079 value between the input width and height, and put the input video at
10080 the center of the padded area:
10082 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
10086 Pad the input to get a final w/h ratio of 16:9:
10088 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
10092 In case of anamorphic video, in order to set the output display aspect
10093 correctly, it is necessary to use @var{sar} in the expression,
10094 according to the relation:
10096 (ih * X / ih) * sar = output_dar
10097 X = output_dar / sar
10100 Thus the previous example needs to be modified to:
10102 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
10106 Double the output size and put the input video in the bottom-right
10107 corner of the output padded area:
10109 pad="2*iw:2*ih:ow-iw:oh-ih"
10113 @anchor{palettegen}
10114 @section palettegen
10116 Generate one palette for a whole video stream.
10118 It accepts the following options:
10122 Set the maximum number of colors to quantize in the palette.
10123 Note: the palette will still contain 256 colors; the unused palette entries
10126 @item reserve_transparent
10127 Create a palette of 255 colors maximum and reserve the last one for
10128 transparency. Reserving the transparency color is useful for GIF optimization.
10129 If not set, the maximum of colors in the palette will be 256. You probably want
10130 to disable this option for a standalone image.
10134 Set statistics mode.
10136 It accepts the following values:
10139 Compute full frame histograms.
10141 Compute histograms only for the part that differs from previous frame. This
10142 might be relevant to give more importance to the moving part of your input if
10143 the background is static.
10146 Default value is @var{full}.
10149 The filter also exports the frame metadata @code{lavfi.color_quant_ratio}
10150 (@code{nb_color_in / nb_color_out}) which you can use to evaluate the degree of
10151 color quantization of the palette. This information is also visible at
10152 @var{info} logging level.
10154 @subsection Examples
10158 Generate a representative palette of a given video using @command{ffmpeg}:
10160 ffmpeg -i input.mkv -vf palettegen palette.png
10164 @section paletteuse
10166 Use a palette to downsample an input video stream.
10168 The filter takes two inputs: one video stream and a palette. The palette must
10169 be a 256 pixels image.
10171 It accepts the following options:
10175 Select dithering mode. Available algorithms are:
10178 Ordered 8x8 bayer dithering (deterministic)
10180 Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
10181 Note: this dithering is sometimes considered "wrong" and is included as a
10183 @item floyd_steinberg
10184 Floyd and Steingberg dithering (error diffusion)
10186 Frankie Sierra dithering v2 (error diffusion)
10188 Frankie Sierra dithering v2 "Lite" (error diffusion)
10191 Default is @var{sierra2_4a}.
10194 When @var{bayer} dithering is selected, this option defines the scale of the
10195 pattern (how much the crosshatch pattern is visible). A low value means more
10196 visible pattern for less banding, and higher value means less visible pattern
10197 at the cost of more banding.
10199 The option must be an integer value in the range [0,5]. Default is @var{2}.
10202 If set, define the zone to process
10206 Only the changing rectangle will be reprocessed. This is similar to GIF
10207 cropping/offsetting compression mechanism. This option can be useful for speed
10208 if only a part of the image is changing, and has use cases such as limiting the
10209 scope of the error diffusal @option{dither} to the rectangle that bounds the
10210 moving scene (it leads to more deterministic output if the scene doesn't change
10211 much, and as a result less moving noise and better GIF compression).
10214 Default is @var{none}.
10217 @subsection Examples
10221 Use a palette (generated for example with @ref{palettegen}) to encode a GIF
10222 using @command{ffmpeg}:
10224 ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
10228 @section perspective
10230 Correct perspective of video not recorded perpendicular to the screen.
10232 A description of the accepted parameters follows.
10243 Set coordinates expression for top left, top right, bottom left and bottom right corners.
10244 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
10245 If the @code{sense} option is set to @code{source}, then the specified points will be sent
10246 to the corners of the destination. If the @code{sense} option is set to @code{destination},
10247 then the corners of the source will be sent to the specified coordinates.
10249 The expressions can use the following variables:
10254 the width and height of video frame.
10258 Output frame count.
10261 @item interpolation
10262 Set interpolation for perspective correction.
10264 It accepts the following values:
10270 Default value is @samp{linear}.
10273 Set interpretation of coordinate options.
10275 It accepts the following values:
10279 Send point in the source specified by the given coordinates to
10280 the corners of the destination.
10282 @item 1, destination
10284 Send the corners of the source to the point in the destination specified
10285 by the given coordinates.
10287 Default value is @samp{source}.
10291 Set when the expressions for coordinates @option{x0,y0,...x3,y3} are evaluated.
10293 It accepts the following values:
10296 only evaluate expressions once during the filter initialization or
10297 when a command is processed
10300 evaluate expressions for each incoming frame
10303 Default value is @samp{init}.
10308 Delay interlaced video by one field time so that the field order changes.
10310 The intended use is to fix PAL movies that have been captured with the
10311 opposite field order to the film-to-video transfer.
10313 A description of the accepted parameters follows.
10319 It accepts the following values:
10322 Capture field order top-first, transfer bottom-first.
10323 Filter will delay the bottom field.
10326 Capture field order bottom-first, transfer top-first.
10327 Filter will delay the top field.
10330 Capture and transfer with the same field order. This mode only exists
10331 for the documentation of the other options to refer to, but if you
10332 actually select it, the filter will faithfully do nothing.
10335 Capture field order determined automatically by field flags, transfer
10337 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
10338 basis using field flags. If no field information is available,
10339 then this works just like @samp{u}.
10342 Capture unknown or varying, transfer opposite.
10343 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
10344 analyzing the images and selecting the alternative that produces best
10345 match between the fields.
10348 Capture top-first, transfer unknown or varying.
10349 Filter selects among @samp{t} and @samp{p} using image analysis.
10352 Capture bottom-first, transfer unknown or varying.
10353 Filter selects among @samp{b} and @samp{p} using image analysis.
10356 Capture determined by field flags, transfer unknown or varying.
10357 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
10358 image analysis. If no field information is available, then this works just
10359 like @samp{U}. This is the default mode.
10362 Both capture and transfer unknown or varying.
10363 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
10367 @section pixdesctest
10369 Pixel format descriptor test filter, mainly useful for internal
10370 testing. The output video should be equal to the input video.
10374 format=monow, pixdesctest
10377 can be used to test the monowhite pixel format descriptor definition.
10381 Enable the specified chain of postprocessing subfilters using libpostproc. This
10382 library should be automatically selected with a GPL build (@code{--enable-gpl}).
10383 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
10384 Each subfilter and some options have a short and a long name that can be used
10385 interchangeably, i.e. dr/dering are the same.
10387 The filters accept the following options:
10391 Set postprocessing subfilters string.
10394 All subfilters share common options to determine their scope:
10398 Honor the quality commands for this subfilter.
10401 Do chrominance filtering, too (default).
10404 Do luminance filtering only (no chrominance).
10407 Do chrominance filtering only (no luminance).
10410 These options can be appended after the subfilter name, separated by a '|'.
10412 Available subfilters are:
10415 @item hb/hdeblock[|difference[|flatness]]
10416 Horizontal deblocking filter
10419 Difference factor where higher values mean more deblocking (default: @code{32}).
10421 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10424 @item vb/vdeblock[|difference[|flatness]]
10425 Vertical deblocking filter
10428 Difference factor where higher values mean more deblocking (default: @code{32}).
10430 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10433 @item ha/hadeblock[|difference[|flatness]]
10434 Accurate horizontal deblocking filter
10437 Difference factor where higher values mean more deblocking (default: @code{32}).
10439 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10442 @item va/vadeblock[|difference[|flatness]]
10443 Accurate vertical deblocking filter
10446 Difference factor where higher values mean more deblocking (default: @code{32}).
10448 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10452 The horizontal and vertical deblocking filters share the difference and
10453 flatness values so you cannot set different horizontal and vertical
10457 @item h1/x1hdeblock
10458 Experimental horizontal deblocking filter
10460 @item v1/x1vdeblock
10461 Experimental vertical deblocking filter
10466 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
10469 larger -> stronger filtering
10471 larger -> stronger filtering
10473 larger -> stronger filtering
10476 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
10479 Stretch luminance to @code{0-255}.
10482 @item lb/linblenddeint
10483 Linear blend deinterlacing filter that deinterlaces the given block by
10484 filtering all lines with a @code{(1 2 1)} filter.
10486 @item li/linipoldeint
10487 Linear interpolating deinterlacing filter that deinterlaces the given block by
10488 linearly interpolating every second line.
10490 @item ci/cubicipoldeint
10491 Cubic interpolating deinterlacing filter deinterlaces the given block by
10492 cubically interpolating every second line.
10494 @item md/mediandeint
10495 Median deinterlacing filter that deinterlaces the given block by applying a
10496 median filter to every second line.
10498 @item fd/ffmpegdeint
10499 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
10500 second line with a @code{(-1 4 2 4 -1)} filter.
10503 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
10504 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
10506 @item fq/forceQuant[|quantizer]
10507 Overrides the quantizer table from the input with the constant quantizer you
10515 Default pp filter combination (@code{hb|a,vb|a,dr|a})
10518 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
10521 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
10524 @subsection Examples
10528 Apply horizontal and vertical deblocking, deringing and automatic
10529 brightness/contrast:
10535 Apply default filters without brightness/contrast correction:
10541 Apply default filters and temporal denoiser:
10543 pp=default/tmpnoise|1|2|3
10547 Apply deblocking on luminance only, and switch vertical deblocking on or off
10548 automatically depending on available CPU time:
10555 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
10556 similar to spp = 6 with 7 point DCT, where only the center sample is
10559 The filter accepts the following options:
10563 Force a constant quantization parameter. It accepts an integer in range
10564 0 to 63. If not set, the filter will use the QP from the video stream
10568 Set thresholding mode. Available modes are:
10572 Set hard thresholding.
10574 Set soft thresholding (better de-ringing effect, but likely blurrier).
10576 Set medium thresholding (good results, default).
10582 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
10583 Ratio) between two input videos.
10585 This filter takes in input two input videos, the first input is
10586 considered the "main" source and is passed unchanged to the
10587 output. The second input is used as a "reference" video for computing
10590 Both video inputs must have the same resolution and pixel format for
10591 this filter to work correctly. Also it assumes that both inputs
10592 have the same number of frames, which are compared one by one.
10594 The obtained average PSNR is printed through the logging system.
10596 The filter stores the accumulated MSE (mean squared error) of each
10597 frame, and at the end of the processing it is averaged across all frames
10598 equally, and the following formula is applied to obtain the PSNR:
10601 PSNR = 10*log10(MAX^2/MSE)
10604 Where MAX is the average of the maximum values of each component of the
10607 The description of the accepted parameters follows.
10610 @item stats_file, f
10611 If specified the filter will use the named file to save the PSNR of
10612 each individual frame. When filename equals "-" the data is sent to
10616 The file printed if @var{stats_file} is selected, contains a sequence of
10617 key/value pairs of the form @var{key}:@var{value} for each compared
10620 A description of each shown parameter follows:
10624 sequential number of the input frame, starting from 1
10627 Mean Square Error pixel-by-pixel average difference of the compared
10628 frames, averaged over all the image components.
10630 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
10631 Mean Square Error pixel-by-pixel average difference of the compared
10632 frames for the component specified by the suffix.
10634 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
10635 Peak Signal to Noise ratio of the compared frames for the component
10636 specified by the suffix.
10641 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
10642 [main][ref] psnr="stats_file=stats.log" [out]
10645 On this example the input file being processed is compared with the
10646 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
10647 is stored in @file{stats.log}.
10652 Pulldown reversal (inverse telecine) filter, capable of handling mixed
10653 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
10656 The pullup filter is designed to take advantage of future context in making
10657 its decisions. This filter is stateless in the sense that it does not lock
10658 onto a pattern to follow, but it instead looks forward to the following
10659 fields in order to identify matches and rebuild progressive frames.
10661 To produce content with an even framerate, insert the fps filter after
10662 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
10663 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
10665 The filter accepts the following options:
10672 These options set the amount of "junk" to ignore at the left, right, top, and
10673 bottom of the image, respectively. Left and right are in units of 8 pixels,
10674 while top and bottom are in units of 2 lines.
10675 The default is 8 pixels on each side.
10678 Set the strict breaks. Setting this option to 1 will reduce the chances of
10679 filter generating an occasional mismatched frame, but it may also cause an
10680 excessive number of frames to be dropped during high motion sequences.
10681 Conversely, setting it to -1 will make filter match fields more easily.
10682 This may help processing of video where there is slight blurring between
10683 the fields, but may also cause there to be interlaced frames in the output.
10684 Default value is @code{0}.
10687 Set the metric plane to use. It accepts the following values:
10693 Use chroma blue plane.
10696 Use chroma red plane.
10699 This option may be set to use chroma plane instead of the default luma plane
10700 for doing filter's computations. This may improve accuracy on very clean
10701 source material, but more likely will decrease accuracy, especially if there
10702 is chroma noise (rainbow effect) or any grayscale video.
10703 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
10704 load and make pullup usable in realtime on slow machines.
10707 For best results (without duplicated frames in the output file) it is
10708 necessary to change the output frame rate. For example, to inverse
10709 telecine NTSC input:
10711 ffmpeg -i input -vf pullup -r 24000/1001 ...
10716 Change video quantization parameters (QP).
10718 The filter accepts the following option:
10722 Set expression for quantization parameter.
10725 The expression is evaluated through the eval API and can contain, among others,
10726 the following constants:
10730 1 if index is not 129, 0 otherwise.
10733 Sequentional index starting from -129 to 128.
10736 @subsection Examples
10740 Some equation like:
10748 Flush video frames from internal cache of frames into a random order.
10749 No frame is discarded.
10750 Inspired by @ref{frei0r} nervous filter.
10754 Set size in number of frames of internal cache, in range from @code{2} to
10755 @code{512}. Default is @code{30}.
10758 Set seed for random number generator, must be an integer included between
10759 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
10760 less than @code{0}, the filter will try to use a good random seed on a
10766 Read vertical interval timecode (VITC) information from the top lines of a
10769 The filter adds frame metadata key @code{lavfi.readvitc.tc_str} with the
10770 timecode value, if a valid timecode has been detected. Further metadata key
10771 @code{lavfi.readvitc.found} is set to 0/1 depending on whether
10772 timecode data has been found or not.
10774 This filter accepts the following options:
10778 Set the maximum number of lines to scan for VITC data. If the value is set to
10779 @code{-1} the full video frame is scanned. Default is @code{45}.
10782 Set the luma threshold for black. Accepts float numbers in the range [0.0,1.0],
10783 default value is @code{0.2}. The value must be equal or less than @code{thr_w}.
10786 Set the luma threshold for white. Accepts float numbers in the range [0.0,1.0],
10787 default value is @code{0.6}. The value must be equal or greater than @code{thr_b}.
10790 @subsection Examples
10794 Detect and draw VITC data onto the video frame; if no valid VITC is detected,
10795 draw @code{--:--:--:--} as a placeholder:
10797 ffmpeg -i input.avi -filter:v 'readvitc,drawtext=fontfile=FreeMono.ttf:text=%@{metadata\\:lavfi.readvitc.tc_str\\:--\\\\\\:--\\\\\\:--\\\\\\:--@}:x=(w-tw)/2:y=400-ascent'
10803 Remap pixels using 2nd: Xmap and 3rd: Ymap input video stream.
10805 Destination pixel at position (X, Y) will be picked from source (x, y) position
10806 where x = Xmap(X, Y) and y = Ymap(X, Y). If mapping values are out of range, zero
10807 value for pixel will be used for destination pixel.
10809 Xmap and Ymap input video streams must be of same dimensions. Output video stream
10810 will have Xmap/Ymap video stream dimensions.
10811 Xmap and Ymap input video streams are 16bit depth, single channel.
10813 @section removegrain
10815 The removegrain filter is a spatial denoiser for progressive video.
10819 Set mode for the first plane.
10822 Set mode for the second plane.
10825 Set mode for the third plane.
10828 Set mode for the fourth plane.
10831 Range of mode is from 0 to 24. Description of each mode follows:
10835 Leave input plane unchanged. Default.
10838 Clips the pixel with the minimum and maximum of the 8 neighbour pixels.
10841 Clips the pixel with the second minimum and maximum of the 8 neighbour pixels.
10844 Clips the pixel with the third minimum and maximum of the 8 neighbour pixels.
10847 Clips the pixel with the fourth minimum and maximum of the 8 neighbour pixels.
10848 This is equivalent to a median filter.
10851 Line-sensitive clipping giving the minimal change.
10854 Line-sensitive clipping, intermediate.
10857 Line-sensitive clipping, intermediate.
10860 Line-sensitive clipping, intermediate.
10863 Line-sensitive clipping on a line where the neighbours pixels are the closest.
10866 Replaces the target pixel with the closest neighbour.
10869 [1 2 1] horizontal and vertical kernel blur.
10875 Bob mode, interpolates top field from the line where the neighbours
10876 pixels are the closest.
10879 Bob mode, interpolates bottom field from the line where the neighbours
10880 pixels are the closest.
10883 Bob mode, interpolates top field. Same as 13 but with a more complicated
10884 interpolation formula.
10887 Bob mode, interpolates bottom field. Same as 14 but with a more complicated
10888 interpolation formula.
10891 Clips the pixel with the minimum and maximum of respectively the maximum and
10892 minimum of each pair of opposite neighbour pixels.
10895 Line-sensitive clipping using opposite neighbours whose greatest distance from
10896 the current pixel is minimal.
10899 Replaces the pixel with the average of its 8 neighbours.
10902 Averages the 9 pixels ([1 1 1] horizontal and vertical blur).
10905 Clips pixels using the averages of opposite neighbour.
10908 Same as mode 21 but simpler and faster.
10911 Small edge and halo removal, but reputed useless.
10917 @section removelogo
10919 Suppress a TV station logo, using an image file to determine which
10920 pixels comprise the logo. It works by filling in the pixels that
10921 comprise the logo with neighboring pixels.
10923 The filter accepts the following options:
10927 Set the filter bitmap file, which can be any image format supported by
10928 libavformat. The width and height of the image file must match those of the
10929 video stream being processed.
10932 Pixels in the provided bitmap image with a value of zero are not
10933 considered part of the logo, non-zero pixels are considered part of
10934 the logo. If you use white (255) for the logo and black (0) for the
10935 rest, you will be safe. For making the filter bitmap, it is
10936 recommended to take a screen capture of a black frame with the logo
10937 visible, and then using a threshold filter followed by the erode
10938 filter once or twice.
10940 If needed, little splotches can be fixed manually. Remember that if
10941 logo pixels are not covered, the filter quality will be much
10942 reduced. Marking too many pixels as part of the logo does not hurt as
10943 much, but it will increase the amount of blurring needed to cover over
10944 the image and will destroy more information than necessary, and extra
10945 pixels will slow things down on a large logo.
10947 @section repeatfields
10949 This filter uses the repeat_field flag from the Video ES headers and hard repeats
10950 fields based on its value.
10952 @section reverse, areverse
10956 Warning: This filter requires memory to buffer the entire clip, so trimming
10959 @subsection Examples
10963 Take the first 5 seconds of a clip, and reverse it.
10971 Rotate video by an arbitrary angle expressed in radians.
10973 The filter accepts the following options:
10975 A description of the optional parameters follows.
10978 Set an expression for the angle by which to rotate the input video
10979 clockwise, expressed as a number of radians. A negative value will
10980 result in a counter-clockwise rotation. By default it is set to "0".
10982 This expression is evaluated for each frame.
10985 Set the output width expression, default value is "iw".
10986 This expression is evaluated just once during configuration.
10989 Set the output height expression, default value is "ih".
10990 This expression is evaluated just once during configuration.
10993 Enable bilinear interpolation if set to 1, a value of 0 disables
10994 it. Default value is 1.
10997 Set the color used to fill the output area not covered by the rotated
10998 image. For the general syntax of this option, check the "Color" section in the
10999 ffmpeg-utils manual. If the special value "none" is selected then no
11000 background is printed (useful for example if the background is never shown).
11002 Default value is "black".
11005 The expressions for the angle and the output size can contain the
11006 following constants and functions:
11010 sequential number of the input frame, starting from 0. It is always NAN
11011 before the first frame is filtered.
11014 time in seconds of the input frame, it is set to 0 when the filter is
11015 configured. It is always NAN before the first frame is filtered.
11019 horizontal and vertical chroma subsample values. For example for the
11020 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11024 the input video width and height
11028 the output width and height, that is the size of the padded area as
11029 specified by the @var{width} and @var{height} expressions
11033 the minimal width/height required for completely containing the input
11034 video rotated by @var{a} radians.
11036 These are only available when computing the @option{out_w} and
11037 @option{out_h} expressions.
11040 @subsection Examples
11044 Rotate the input by PI/6 radians clockwise:
11050 Rotate the input by PI/6 radians counter-clockwise:
11056 Rotate the input by 45 degrees clockwise:
11062 Apply a constant rotation with period T, starting from an angle of PI/3:
11064 rotate=PI/3+2*PI*t/T
11068 Make the input video rotation oscillating with a period of T
11069 seconds and an amplitude of A radians:
11071 rotate=A*sin(2*PI/T*t)
11075 Rotate the video, output size is chosen so that the whole rotating
11076 input video is always completely contained in the output:
11078 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
11082 Rotate the video, reduce the output size so that no background is ever
11085 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
11089 @subsection Commands
11091 The filter supports the following commands:
11095 Set the angle expression.
11096 The command accepts the same syntax of the corresponding option.
11098 If the specified expression is not valid, it is kept at its current
11104 Apply Shape Adaptive Blur.
11106 The filter accepts the following options:
11109 @item luma_radius, lr
11110 Set luma blur filter strength, must be a value in range 0.1-4.0, default
11111 value is 1.0. A greater value will result in a more blurred image, and
11112 in slower processing.
11114 @item luma_pre_filter_radius, lpfr
11115 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
11118 @item luma_strength, ls
11119 Set luma maximum difference between pixels to still be considered, must
11120 be a value in the 0.1-100.0 range, default value is 1.0.
11122 @item chroma_radius, cr
11123 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
11124 greater value will result in a more blurred image, and in slower
11127 @item chroma_pre_filter_radius, cpfr
11128 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
11130 @item chroma_strength, cs
11131 Set chroma maximum difference between pixels to still be considered,
11132 must be a value in the 0.1-100.0 range.
11135 Each chroma option value, if not explicitly specified, is set to the
11136 corresponding luma option value.
11141 Scale (resize) the input video, using the libswscale library.
11143 The scale filter forces the output display aspect ratio to be the same
11144 of the input, by changing the output sample aspect ratio.
11146 If the input image format is different from the format requested by
11147 the next filter, the scale filter will convert the input to the
11150 @subsection Options
11151 The filter accepts the following options, or any of the options
11152 supported by the libswscale scaler.
11154 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
11155 the complete list of scaler options.
11160 Set the output video dimension expression. Default value is the input
11163 If the value is 0, the input width is used for the output.
11165 If one of the values is -1, the scale filter will use a value that
11166 maintains the aspect ratio of the input image, calculated from the
11167 other specified dimension. If both of them are -1, the input size is
11170 If one of the values is -n with n > 1, the scale filter will also use a value
11171 that maintains the aspect ratio of the input image, calculated from the other
11172 specified dimension. After that it will, however, make sure that the calculated
11173 dimension is divisible by n and adjust the value if necessary.
11175 See below for the list of accepted constants for use in the dimension
11179 Specify when to evaluate @var{width} and @var{height} expression. It accepts the following values:
11183 Only evaluate expressions once during the filter initialization or when a command is processed.
11186 Evaluate expressions for each incoming frame.
11190 Default value is @samp{init}.
11194 Set the interlacing mode. It accepts the following values:
11198 Force interlaced aware scaling.
11201 Do not apply interlaced scaling.
11204 Select interlaced aware scaling depending on whether the source frames
11205 are flagged as interlaced or not.
11208 Default value is @samp{0}.
11211 Set libswscale scaling flags. See
11212 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
11213 complete list of values. If not explicitly specified the filter applies
11217 @item param0, param1
11218 Set libswscale input parameters for scaling algorithms that need them. See
11219 @ref{sws_params,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
11220 complete documentation. If not explicitly specified the filter applies
11226 Set the video size. For the syntax of this option, check the
11227 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11229 @item in_color_matrix
11230 @item out_color_matrix
11231 Set in/output YCbCr color space type.
11233 This allows the autodetected value to be overridden as well as allows forcing
11234 a specific value used for the output and encoder.
11236 If not specified, the color space type depends on the pixel format.
11242 Choose automatically.
11245 Format conforming to International Telecommunication Union (ITU)
11246 Recommendation BT.709.
11249 Set color space conforming to the United States Federal Communications
11250 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
11253 Set color space conforming to:
11257 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
11260 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
11263 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
11268 Set color space conforming to SMPTE ST 240:1999.
11273 Set in/output YCbCr sample range.
11275 This allows the autodetected value to be overridden as well as allows forcing
11276 a specific value used for the output and encoder. If not specified, the
11277 range depends on the pixel format. Possible values:
11281 Choose automatically.
11284 Set full range (0-255 in case of 8-bit luma).
11287 Set "MPEG" range (16-235 in case of 8-bit luma).
11290 @item force_original_aspect_ratio
11291 Enable decreasing or increasing output video width or height if necessary to
11292 keep the original aspect ratio. Possible values:
11296 Scale the video as specified and disable this feature.
11299 The output video dimensions will automatically be decreased if needed.
11302 The output video dimensions will automatically be increased if needed.
11306 One useful instance of this option is that when you know a specific device's
11307 maximum allowed resolution, you can use this to limit the output video to
11308 that, while retaining the aspect ratio. For example, device A allows
11309 1280x720 playback, and your video is 1920x800. Using this option (set it to
11310 decrease) and specifying 1280x720 to the command line makes the output
11313 Please note that this is a different thing than specifying -1 for @option{w}
11314 or @option{h}, you still need to specify the output resolution for this option
11319 The values of the @option{w} and @option{h} options are expressions
11320 containing the following constants:
11325 The input width and height
11329 These are the same as @var{in_w} and @var{in_h}.
11333 The output (scaled) width and height
11337 These are the same as @var{out_w} and @var{out_h}
11340 The same as @var{iw} / @var{ih}
11343 input sample aspect ratio
11346 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
11350 horizontal and vertical input chroma subsample values. For example for the
11351 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11355 horizontal and vertical output chroma subsample values. For example for the
11356 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11359 @subsection Examples
11363 Scale the input video to a size of 200x100
11368 This is equivalent to:
11379 Specify a size abbreviation for the output size:
11384 which can also be written as:
11390 Scale the input to 2x:
11392 scale=w=2*iw:h=2*ih
11396 The above is the same as:
11398 scale=2*in_w:2*in_h
11402 Scale the input to 2x with forced interlaced scaling:
11404 scale=2*iw:2*ih:interl=1
11408 Scale the input to half size:
11410 scale=w=iw/2:h=ih/2
11414 Increase the width, and set the height to the same size:
11420 Seek Greek harmony:
11427 Increase the height, and set the width to 3/2 of the height:
11429 scale=w=3/2*oh:h=3/5*ih
11433 Increase the size, making the size a multiple of the chroma
11436 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
11440 Increase the width to a maximum of 500 pixels,
11441 keeping the same aspect ratio as the input:
11443 scale=w='min(500\, iw*3/2):h=-1'
11447 @subsection Commands
11449 This filter supports the following commands:
11453 Set the output video dimension expression.
11454 The command accepts the same syntax of the corresponding option.
11456 If the specified expression is not valid, it is kept at its current
11462 Scale (resize) the input video, based on a reference video.
11464 See the scale filter for available options, scale2ref supports the same but
11465 uses the reference video instead of the main input as basis.
11467 @subsection Examples
11471 Scale a subtitle stream to match the main video in size before overlaying
11473 'scale2ref[b][a];[a][b]overlay'
11477 @anchor{selectivecolor}
11478 @section selectivecolor
11480 Adjust cyan, magenta, yellow and black (CMYK) to certain ranges of colors (such
11481 as "reds", "yellows", "greens", "cyans", ...). The adjustment range is defined
11482 by the "purity" of the color (that is, how saturated it already is).
11484 This filter is similar to the Adobe Photoshop Selective Color tool.
11486 The filter accepts the following options:
11489 @item correction_method
11490 Select color correction method.
11492 Available values are:
11495 Specified adjustments are applied "as-is" (added/subtracted to original pixel
11498 Specified adjustments are relative to the original component value.
11500 Default is @code{absolute}.
11502 Adjustments for red pixels (pixels where the red component is the maximum)
11504 Adjustments for yellow pixels (pixels where the blue component is the minimum)
11506 Adjustments for green pixels (pixels where the green component is the maximum)
11508 Adjustments for cyan pixels (pixels where the red component is the minimum)
11510 Adjustments for blue pixels (pixels where the blue component is the maximum)
11512 Adjustments for magenta pixels (pixels where the green component is the minimum)
11514 Adjustments for white pixels (pixels where all components are greater than 128)
11516 Adjustments for all pixels except pure black and pure white
11518 Adjustments for black pixels (pixels where all components are lesser than 128)
11520 Specify a Photoshop selective color file (@code{.asv}) to import the settings from.
11523 All the adjustment settings (@option{reds}, @option{yellows}, ...) accept up to
11524 4 space separated floating point adjustment values in the [-1,1] range,
11525 respectively to adjust the amount of cyan, magenta, yellow and black for the
11526 pixels of its range.
11528 @subsection Examples
11532 Increase cyan by 50% and reduce yellow by 33% in every green areas, and
11533 increase magenta by 27% in blue areas:
11535 selectivecolor=greens=.5 0 -.33 0:blues=0 .27
11539 Use a Photoshop selective color preset:
11541 selectivecolor=psfile=MySelectiveColorPresets/Misty.asv
11545 @section separatefields
11547 The @code{separatefields} takes a frame-based video input and splits
11548 each frame into its components fields, producing a new half height clip
11549 with twice the frame rate and twice the frame count.
11551 This filter use field-dominance information in frame to decide which
11552 of each pair of fields to place first in the output.
11553 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
11555 @section setdar, setsar
11557 The @code{setdar} filter sets the Display Aspect Ratio for the filter
11560 This is done by changing the specified Sample (aka Pixel) Aspect
11561 Ratio, according to the following equation:
11563 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
11566 Keep in mind that the @code{setdar} filter does not modify the pixel
11567 dimensions of the video frame. Also, the display aspect ratio set by
11568 this filter may be changed by later filters in the filterchain,
11569 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
11572 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
11573 the filter output video.
11575 Note that as a consequence of the application of this filter, the
11576 output display aspect ratio will change according to the equation
11579 Keep in mind that the sample aspect ratio set by the @code{setsar}
11580 filter may be changed by later filters in the filterchain, e.g. if
11581 another "setsar" or a "setdar" filter is applied.
11583 It accepts the following parameters:
11586 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
11587 Set the aspect ratio used by the filter.
11589 The parameter can be a floating point number string, an expression, or
11590 a string of the form @var{num}:@var{den}, where @var{num} and
11591 @var{den} are the numerator and denominator of the aspect ratio. If
11592 the parameter is not specified, it is assumed the value "0".
11593 In case the form "@var{num}:@var{den}" is used, the @code{:} character
11597 Set the maximum integer value to use for expressing numerator and
11598 denominator when reducing the expressed aspect ratio to a rational.
11599 Default value is @code{100}.
11603 The parameter @var{sar} is an expression containing
11604 the following constants:
11608 These are approximated values for the mathematical constants e
11609 (Euler's number), pi (Greek pi), and phi (the golden ratio).
11612 The input width and height.
11615 These are the same as @var{w} / @var{h}.
11618 The input sample aspect ratio.
11621 The input display aspect ratio. It is the same as
11622 (@var{w} / @var{h}) * @var{sar}.
11625 Horizontal and vertical chroma subsample values. For example, for the
11626 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11629 @subsection Examples
11634 To change the display aspect ratio to 16:9, specify one of the following:
11642 To change the sample aspect ratio to 10:11, specify:
11648 To set a display aspect ratio of 16:9, and specify a maximum integer value of
11649 1000 in the aspect ratio reduction, use the command:
11651 setdar=ratio=16/9:max=1000
11659 Force field for the output video frame.
11661 The @code{setfield} filter marks the interlace type field for the
11662 output frames. It does not change the input frame, but only sets the
11663 corresponding property, which affects how the frame is treated by
11664 following filters (e.g. @code{fieldorder} or @code{yadif}).
11666 The filter accepts the following options:
11671 Available values are:
11675 Keep the same field property.
11678 Mark the frame as bottom-field-first.
11681 Mark the frame as top-field-first.
11684 Mark the frame as progressive.
11690 Show a line containing various information for each input video frame.
11691 The input video is not modified.
11693 The shown line contains a sequence of key/value pairs of the form
11694 @var{key}:@var{value}.
11696 The following values are shown in the output:
11700 The (sequential) number of the input frame, starting from 0.
11703 The Presentation TimeStamp of the input frame, expressed as a number of
11704 time base units. The time base unit depends on the filter input pad.
11707 The Presentation TimeStamp of the input frame, expressed as a number of
11711 The position of the frame in the input stream, or -1 if this information is
11712 unavailable and/or meaningless (for example in case of synthetic video).
11715 The pixel format name.
11718 The sample aspect ratio of the input frame, expressed in the form
11719 @var{num}/@var{den}.
11722 The size of the input frame. For the syntax of this option, check the
11723 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11726 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
11727 for bottom field first).
11730 This is 1 if the frame is a key frame, 0 otherwise.
11733 The picture type of the input frame ("I" for an I-frame, "P" for a
11734 P-frame, "B" for a B-frame, or "?" for an unknown type).
11735 Also refer to the documentation of the @code{AVPictureType} enum and of
11736 the @code{av_get_picture_type_char} function defined in
11737 @file{libavutil/avutil.h}.
11740 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
11742 @item plane_checksum
11743 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
11744 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
11747 @section showpalette
11749 Displays the 256 colors palette of each frame. This filter is only relevant for
11750 @var{pal8} pixel format frames.
11752 It accepts the following option:
11756 Set the size of the box used to represent one palette color entry. Default is
11757 @code{30} (for a @code{30x30} pixel box).
11760 @section shuffleframes
11762 Reorder and/or duplicate video frames.
11764 It accepts the following parameters:
11768 Set the destination indexes of input frames.
11769 This is space or '|' separated list of indexes that maps input frames to output
11770 frames. Number of indexes also sets maximal value that each index may have.
11773 The first frame has the index 0. The default is to keep the input unchanged.
11775 Swap second and third frame of every three frames of the input:
11777 ffmpeg -i INPUT -vf "shuffleframes=0 2 1" OUTPUT
11780 @section shuffleplanes
11782 Reorder and/or duplicate video planes.
11784 It accepts the following parameters:
11789 The index of the input plane to be used as the first output plane.
11792 The index of the input plane to be used as the second output plane.
11795 The index of the input plane to be used as the third output plane.
11798 The index of the input plane to be used as the fourth output plane.
11802 The first plane has the index 0. The default is to keep the input unchanged.
11804 Swap the second and third planes of the input:
11806 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
11809 @anchor{signalstats}
11810 @section signalstats
11811 Evaluate various visual metrics that assist in determining issues associated
11812 with the digitization of analog video media.
11814 By default the filter will log these metadata values:
11818 Display the minimal Y value contained within the input frame. Expressed in
11822 Display the Y value at the 10% percentile within the input frame. Expressed in
11826 Display the average Y value within the input frame. Expressed in range of
11830 Display the Y value at the 90% percentile within the input frame. Expressed in
11834 Display the maximum Y value contained within the input frame. Expressed in
11838 Display the minimal U value contained within the input frame. Expressed in
11842 Display the U value at the 10% percentile within the input frame. Expressed in
11846 Display the average U value within the input frame. Expressed in range of
11850 Display the U value at the 90% percentile within the input frame. Expressed in
11854 Display the maximum U value contained within the input frame. Expressed in
11858 Display the minimal V value contained within the input frame. Expressed in
11862 Display the V value at the 10% percentile within the input frame. Expressed in
11866 Display the average V value within the input frame. Expressed in range of
11870 Display the V value at the 90% percentile within the input frame. Expressed in
11874 Display the maximum V value contained within the input frame. Expressed in
11878 Display the minimal saturation value contained within the input frame.
11879 Expressed in range of [0-~181.02].
11882 Display the saturation value at the 10% percentile within the input frame.
11883 Expressed in range of [0-~181.02].
11886 Display the average saturation value within the input frame. Expressed in range
11890 Display the saturation value at the 90% percentile within the input frame.
11891 Expressed in range of [0-~181.02].
11894 Display the maximum saturation value contained within the input frame.
11895 Expressed in range of [0-~181.02].
11898 Display the median value for hue within the input frame. Expressed in range of
11902 Display the average value for hue within the input frame. Expressed in range of
11906 Display the average of sample value difference between all values of the Y
11907 plane in the current frame and corresponding values of the previous input frame.
11908 Expressed in range of [0-255].
11911 Display the average of sample value difference between all values of the U
11912 plane in the current frame and corresponding values of the previous input frame.
11913 Expressed in range of [0-255].
11916 Display the average of sample value difference between all values of the V
11917 plane in the current frame and corresponding values of the previous input frame.
11918 Expressed in range of [0-255].
11921 The filter accepts the following options:
11927 @option{stat} specify an additional form of image analysis.
11928 @option{out} output video with the specified type of pixel highlighted.
11930 Both options accept the following values:
11934 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
11935 unlike the neighboring pixels of the same field. Examples of temporal outliers
11936 include the results of video dropouts, head clogs, or tape tracking issues.
11939 Identify @var{vertical line repetition}. Vertical line repetition includes
11940 similar rows of pixels within a frame. In born-digital video vertical line
11941 repetition is common, but this pattern is uncommon in video digitized from an
11942 analog source. When it occurs in video that results from the digitization of an
11943 analog source it can indicate concealment from a dropout compensator.
11946 Identify pixels that fall outside of legal broadcast range.
11950 Set the highlight color for the @option{out} option. The default color is
11954 @subsection Examples
11958 Output data of various video metrics:
11960 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
11964 Output specific data about the minimum and maximum values of the Y plane per frame:
11966 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
11970 Playback video while highlighting pixels that are outside of broadcast range in red.
11972 ffplay example.mov -vf signalstats="out=brng:color=red"
11976 Playback video with signalstats metadata drawn over the frame.
11978 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
11981 The contents of signalstat_drawtext.txt used in the command are:
11984 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
11985 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
11986 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
11987 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
11995 Blur the input video without impacting the outlines.
11997 It accepts the following options:
12000 @item luma_radius, lr
12001 Set the luma radius. The option value must be a float number in
12002 the range [0.1,5.0] that specifies the variance of the gaussian filter
12003 used to blur the image (slower if larger). Default value is 1.0.
12005 @item luma_strength, ls
12006 Set the luma strength. The option value must be a float number
12007 in the range [-1.0,1.0] that configures the blurring. A value included
12008 in [0.0,1.0] will blur the image whereas a value included in
12009 [-1.0,0.0] will sharpen the image. Default value is 1.0.
12011 @item luma_threshold, lt
12012 Set the luma threshold used as a coefficient to determine
12013 whether a pixel should be blurred or not. The option value must be an
12014 integer in the range [-30,30]. A value of 0 will filter all the image,
12015 a value included in [0,30] will filter flat areas and a value included
12016 in [-30,0] will filter edges. Default value is 0.
12018 @item chroma_radius, cr
12019 Set the chroma radius. The option value must be a float number in
12020 the range [0.1,5.0] that specifies the variance of the gaussian filter
12021 used to blur the image (slower if larger). Default value is 1.0.
12023 @item chroma_strength, cs
12024 Set the chroma strength. The option value must be a float number
12025 in the range [-1.0,1.0] that configures the blurring. A value included
12026 in [0.0,1.0] will blur the image whereas a value included in
12027 [-1.0,0.0] will sharpen the image. Default value is 1.0.
12029 @item chroma_threshold, ct
12030 Set the chroma threshold used as a coefficient to determine
12031 whether a pixel should be blurred or not. The option value must be an
12032 integer in the range [-30,30]. A value of 0 will filter all the image,
12033 a value included in [0,30] will filter flat areas and a value included
12034 in [-30,0] will filter edges. Default value is 0.
12037 If a chroma option is not explicitly set, the corresponding luma value
12042 Obtain the SSIM (Structural SImilarity Metric) between two input videos.
12044 This filter takes in input two input videos, the first input is
12045 considered the "main" source and is passed unchanged to the
12046 output. The second input is used as a "reference" video for computing
12049 Both video inputs must have the same resolution and pixel format for
12050 this filter to work correctly. Also it assumes that both inputs
12051 have the same number of frames, which are compared one by one.
12053 The filter stores the calculated SSIM of each frame.
12055 The description of the accepted parameters follows.
12058 @item stats_file, f
12059 If specified the filter will use the named file to save the SSIM of
12060 each individual frame. When filename equals "-" the data is sent to
12064 The file printed if @var{stats_file} is selected, contains a sequence of
12065 key/value pairs of the form @var{key}:@var{value} for each compared
12068 A description of each shown parameter follows:
12072 sequential number of the input frame, starting from 1
12074 @item Y, U, V, R, G, B
12075 SSIM of the compared frames for the component specified by the suffix.
12078 SSIM of the compared frames for the whole frame.
12081 Same as above but in dB representation.
12086 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
12087 [main][ref] ssim="stats_file=stats.log" [out]
12090 On this example the input file being processed is compared with the
12091 reference file @file{ref_movie.mpg}. The SSIM of each individual frame
12092 is stored in @file{stats.log}.
12094 Another example with both psnr and ssim at same time:
12096 ffmpeg -i main.mpg -i ref.mpg -lavfi "ssim;[0:v][1:v]psnr" -f null -
12101 Convert between different stereoscopic image formats.
12103 The filters accept the following options:
12107 Set stereoscopic image format of input.
12109 Available values for input image formats are:
12112 side by side parallel (left eye left, right eye right)
12115 side by side crosseye (right eye left, left eye right)
12118 side by side parallel with half width resolution
12119 (left eye left, right eye right)
12122 side by side crosseye with half width resolution
12123 (right eye left, left eye right)
12126 above-below (left eye above, right eye below)
12129 above-below (right eye above, left eye below)
12132 above-below with half height resolution
12133 (left eye above, right eye below)
12136 above-below with half height resolution
12137 (right eye above, left eye below)
12140 alternating frames (left eye first, right eye second)
12143 alternating frames (right eye first, left eye second)
12146 interleaved rows (left eye has top row, right eye starts on next row)
12149 interleaved rows (right eye has top row, left eye starts on next row)
12152 interleaved columns, left eye first
12155 interleaved columns, right eye first
12157 Default value is @samp{sbsl}.
12161 Set stereoscopic image format of output.
12165 side by side parallel (left eye left, right eye right)
12168 side by side crosseye (right eye left, left eye right)
12171 side by side parallel with half width resolution
12172 (left eye left, right eye right)
12175 side by side crosseye with half width resolution
12176 (right eye left, left eye right)
12179 above-below (left eye above, right eye below)
12182 above-below (right eye above, left eye below)
12185 above-below with half height resolution
12186 (left eye above, right eye below)
12189 above-below with half height resolution
12190 (right eye above, left eye below)
12193 alternating frames (left eye first, right eye second)
12196 alternating frames (right eye first, left eye second)
12199 interleaved rows (left eye has top row, right eye starts on next row)
12202 interleaved rows (right eye has top row, left eye starts on next row)
12205 anaglyph red/blue gray
12206 (red filter on left eye, blue filter on right eye)
12209 anaglyph red/green gray
12210 (red filter on left eye, green filter on right eye)
12213 anaglyph red/cyan gray
12214 (red filter on left eye, cyan filter on right eye)
12217 anaglyph red/cyan half colored
12218 (red filter on left eye, cyan filter on right eye)
12221 anaglyph red/cyan color
12222 (red filter on left eye, cyan filter on right eye)
12225 anaglyph red/cyan color optimized with the least squares projection of dubois
12226 (red filter on left eye, cyan filter on right eye)
12229 anaglyph green/magenta gray
12230 (green filter on left eye, magenta filter on right eye)
12233 anaglyph green/magenta half colored
12234 (green filter on left eye, magenta filter on right eye)
12237 anaglyph green/magenta colored
12238 (green filter on left eye, magenta filter on right eye)
12241 anaglyph green/magenta color optimized with the least squares projection of dubois
12242 (green filter on left eye, magenta filter on right eye)
12245 anaglyph yellow/blue gray
12246 (yellow filter on left eye, blue filter on right eye)
12249 anaglyph yellow/blue half colored
12250 (yellow filter on left eye, blue filter on right eye)
12253 anaglyph yellow/blue colored
12254 (yellow filter on left eye, blue filter on right eye)
12257 anaglyph yellow/blue color optimized with the least squares projection of dubois
12258 (yellow filter on left eye, blue filter on right eye)
12261 mono output (left eye only)
12264 mono output (right eye only)
12267 checkerboard, left eye first
12270 checkerboard, right eye first
12273 interleaved columns, left eye first
12276 interleaved columns, right eye first
12279 Default value is @samp{arcd}.
12282 @subsection Examples
12286 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
12292 Convert input video from above below (left eye above, right eye below) to side by side crosseye.
12298 @section streamselect, astreamselect
12299 Select video or audio streams.
12301 The filter accepts the following options:
12305 Set number of inputs. Default is 2.
12308 Set input indexes to remap to outputs.
12311 @subsection Commands
12313 The @code{streamselect} and @code{astreamselect} filter supports the following
12318 Set input indexes to remap to outputs.
12321 @subsection Examples
12325 Select first 5 seconds 1st stream and rest of time 2nd stream:
12327 sendcmd='5.0 streamselect map 1',streamselect=inputs=2:map=0
12331 Same as above, but for audio:
12333 asendcmd='5.0 astreamselect map 1',astreamselect=inputs=2:map=0
12340 Apply a simple postprocessing filter that compresses and decompresses the image
12341 at several (or - in the case of @option{quality} level @code{6} - all) shifts
12342 and average the results.
12344 The filter accepts the following options:
12348 Set quality. This option defines the number of levels for averaging. It accepts
12349 an integer in the range 0-6. If set to @code{0}, the filter will have no
12350 effect. A value of @code{6} means the higher quality. For each increment of
12351 that value the speed drops by a factor of approximately 2. Default value is
12355 Force a constant quantization parameter. If not set, the filter will use the QP
12356 from the video stream (if available).
12359 Set thresholding mode. Available modes are:
12363 Set hard thresholding (default).
12365 Set soft thresholding (better de-ringing effect, but likely blurrier).
12368 @item use_bframe_qp
12369 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
12370 option may cause flicker since the B-Frames have often larger QP. Default is
12371 @code{0} (not enabled).
12377 Draw subtitles on top of input video using the libass library.
12379 To enable compilation of this filter you need to configure FFmpeg with
12380 @code{--enable-libass}. This filter also requires a build with libavcodec and
12381 libavformat to convert the passed subtitles file to ASS (Advanced Substation
12382 Alpha) subtitles format.
12384 The filter accepts the following options:
12388 Set the filename of the subtitle file to read. It must be specified.
12390 @item original_size
12391 Specify the size of the original video, the video for which the ASS file
12392 was composed. For the syntax of this option, check the
12393 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12394 Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
12395 correctly scale the fonts if the aspect ratio has been changed.
12398 Set a directory path containing fonts that can be used by the filter.
12399 These fonts will be used in addition to whatever the font provider uses.
12402 Set subtitles input character encoding. @code{subtitles} filter only. Only
12403 useful if not UTF-8.
12405 @item stream_index, si
12406 Set subtitles stream index. @code{subtitles} filter only.
12409 Override default style or script info parameters of the subtitles. It accepts a
12410 string containing ASS style format @code{KEY=VALUE} couples separated by ",".
12413 If the first key is not specified, it is assumed that the first value
12414 specifies the @option{filename}.
12416 For example, to render the file @file{sub.srt} on top of the input
12417 video, use the command:
12422 which is equivalent to:
12424 subtitles=filename=sub.srt
12427 To render the default subtitles stream from file @file{video.mkv}, use:
12429 subtitles=video.mkv
12432 To render the second subtitles stream from that file, use:
12434 subtitles=video.mkv:si=1
12437 To make the subtitles stream from @file{sub.srt} appear in transparent green
12438 @code{DejaVu Serif}, use:
12440 subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'
12443 @section super2xsai
12445 Scale the input by 2x and smooth using the Super2xSaI (Scale and
12446 Interpolate) pixel art scaling algorithm.
12448 Useful for enlarging pixel art images without reducing sharpness.
12452 Swap two rectangular objects in video.
12454 This filter accepts the following options:
12464 Set 1st rect x coordinate.
12467 Set 1st rect y coordinate.
12470 Set 2nd rect x coordinate.
12473 Set 2nd rect y coordinate.
12475 All expressions are evaluated once for each frame.
12478 The all options are expressions containing the following constants:
12483 The input width and height.
12486 same as @var{w} / @var{h}
12489 input sample aspect ratio
12492 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
12495 The number of the input frame, starting from 0.
12498 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
12501 the position in the file of the input frame, NAN if unknown
12509 Apply telecine process to the video.
12511 This filter accepts the following options:
12520 The default value is @code{top}.
12524 A string of numbers representing the pulldown pattern you wish to apply.
12525 The default value is @code{23}.
12529 Some typical patterns:
12534 24p: 2332 (preferred)
12541 24p: 222222222223 ("Euro pulldown")
12547 Select the most representative frame in a given sequence of consecutive frames.
12549 The filter accepts the following options:
12553 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
12554 will pick one of them, and then handle the next batch of @var{n} frames until
12555 the end. Default is @code{100}.
12558 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
12559 value will result in a higher memory usage, so a high value is not recommended.
12561 @subsection Examples
12565 Extract one picture each 50 frames:
12571 Complete example of a thumbnail creation with @command{ffmpeg}:
12573 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
12579 Tile several successive frames together.
12581 The filter accepts the following options:
12586 Set the grid size (i.e. the number of lines and columns). For the syntax of
12587 this option, check the
12588 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12591 Set the maximum number of frames to render in the given area. It must be less
12592 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
12593 the area will be used.
12596 Set the outer border margin in pixels.
12599 Set the inner border thickness (i.e. the number of pixels between frames). For
12600 more advanced padding options (such as having different values for the edges),
12601 refer to the pad video filter.
12604 Specify the color of the unused area. For the syntax of this option, check the
12605 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
12609 @subsection Examples
12613 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
12615 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
12617 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
12618 duplicating each output frame to accommodate the originally detected frame
12622 Display @code{5} pictures in an area of @code{3x2} frames,
12623 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
12624 mixed flat and named options:
12626 tile=3x2:nb_frames=5:padding=7:margin=2
12630 @section tinterlace
12632 Perform various types of temporal field interlacing.
12634 Frames are counted starting from 1, so the first input frame is
12637 The filter accepts the following options:
12642 Specify the mode of the interlacing. This option can also be specified
12643 as a value alone. See below for a list of values for this option.
12645 Available values are:
12649 Move odd frames into the upper field, even into the lower field,
12650 generating a double height frame at half frame rate.
12654 Frame 1 Frame 2 Frame 3 Frame 4
12656 11111 22222 33333 44444
12657 11111 22222 33333 44444
12658 11111 22222 33333 44444
12659 11111 22222 33333 44444
12673 Only output odd frames, even frames are dropped, generating a frame with
12674 unchanged height at half frame rate.
12679 Frame 1 Frame 2 Frame 3 Frame 4
12681 11111 22222 33333 44444
12682 11111 22222 33333 44444
12683 11111 22222 33333 44444
12684 11111 22222 33333 44444
12694 Only output even frames, odd frames are dropped, generating a frame with
12695 unchanged height at half frame rate.
12700 Frame 1 Frame 2 Frame 3 Frame 4
12702 11111 22222 33333 44444
12703 11111 22222 33333 44444
12704 11111 22222 33333 44444
12705 11111 22222 33333 44444
12715 Expand each frame to full height, but pad alternate lines with black,
12716 generating a frame with double height at the same input frame rate.
12721 Frame 1 Frame 2 Frame 3 Frame 4
12723 11111 22222 33333 44444
12724 11111 22222 33333 44444
12725 11111 22222 33333 44444
12726 11111 22222 33333 44444
12729 11111 ..... 33333 .....
12730 ..... 22222 ..... 44444
12731 11111 ..... 33333 .....
12732 ..... 22222 ..... 44444
12733 11111 ..... 33333 .....
12734 ..... 22222 ..... 44444
12735 11111 ..... 33333 .....
12736 ..... 22222 ..... 44444
12740 @item interleave_top, 4
12741 Interleave the upper field from odd frames with the lower field from
12742 even frames, generating a frame with unchanged height at half frame rate.
12747 Frame 1 Frame 2 Frame 3 Frame 4
12749 11111<- 22222 33333<- 44444
12750 11111 22222<- 33333 44444<-
12751 11111<- 22222 33333<- 44444
12752 11111 22222<- 33333 44444<-
12762 @item interleave_bottom, 5
12763 Interleave the lower field from odd frames with the upper field from
12764 even frames, generating a frame with unchanged height at half frame rate.
12769 Frame 1 Frame 2 Frame 3 Frame 4
12771 11111 22222<- 33333 44444<-
12772 11111<- 22222 33333<- 44444
12773 11111 22222<- 33333 44444<-
12774 11111<- 22222 33333<- 44444
12784 @item interlacex2, 6
12785 Double frame rate with unchanged height. Frames are inserted each
12786 containing the second temporal field from the previous input frame and
12787 the first temporal field from the next input frame. This mode relies on
12788 the top_field_first flag. Useful for interlaced video displays with no
12789 field synchronisation.
12794 Frame 1 Frame 2 Frame 3 Frame 4
12796 11111 22222 33333 44444
12797 11111 22222 33333 44444
12798 11111 22222 33333 44444
12799 11111 22222 33333 44444
12802 11111 22222 22222 33333 33333 44444 44444
12803 11111 11111 22222 22222 33333 33333 44444
12804 11111 22222 22222 33333 33333 44444 44444
12805 11111 11111 22222 22222 33333 33333 44444
12810 Move odd frames into the upper field, even into the lower field,
12811 generating a double height frame at same frame rate.
12816 Frame 1 Frame 2 Frame 3 Frame 4
12818 11111 22222 33333 44444
12819 11111 22222 33333 44444
12820 11111 22222 33333 44444
12821 11111 22222 33333 44444
12824 11111 33333 33333 55555
12825 22222 22222 44444 44444
12826 11111 33333 33333 55555
12827 22222 22222 44444 44444
12828 11111 33333 33333 55555
12829 22222 22222 44444 44444
12830 11111 33333 33333 55555
12831 22222 22222 44444 44444
12836 Numeric values are deprecated but are accepted for backward
12837 compatibility reasons.
12839 Default mode is @code{merge}.
12842 Specify flags influencing the filter process.
12844 Available value for @var{flags} is:
12847 @item low_pass_filter, vlfp
12848 Enable vertical low-pass filtering in the filter.
12849 Vertical low-pass filtering is required when creating an interlaced
12850 destination from a progressive source which contains high-frequency
12851 vertical detail. Filtering will reduce interlace 'twitter' and Moire
12854 Vertical low-pass filtering can only be enabled for @option{mode}
12855 @var{interleave_top} and @var{interleave_bottom}.
12862 Transpose rows with columns in the input video and optionally flip it.
12864 It accepts the following parameters:
12869 Specify the transposition direction.
12871 Can assume the following values:
12873 @item 0, 4, cclock_flip
12874 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
12882 Rotate by 90 degrees clockwise, that is:
12890 Rotate by 90 degrees counterclockwise, that is:
12897 @item 3, 7, clock_flip
12898 Rotate by 90 degrees clockwise and vertically flip, that is:
12906 For values between 4-7, the transposition is only done if the input
12907 video geometry is portrait and not landscape. These values are
12908 deprecated, the @code{passthrough} option should be used instead.
12910 Numerical values are deprecated, and should be dropped in favor of
12911 symbolic constants.
12914 Do not apply the transposition if the input geometry matches the one
12915 specified by the specified value. It accepts the following values:
12918 Always apply transposition.
12920 Preserve portrait geometry (when @var{height} >= @var{width}).
12922 Preserve landscape geometry (when @var{width} >= @var{height}).
12925 Default value is @code{none}.
12928 For example to rotate by 90 degrees clockwise and preserve portrait
12931 transpose=dir=1:passthrough=portrait
12934 The command above can also be specified as:
12936 transpose=1:portrait
12940 Trim the input so that the output contains one continuous subpart of the input.
12942 It accepts the following parameters:
12945 Specify the time of the start of the kept section, i.e. the frame with the
12946 timestamp @var{start} will be the first frame in the output.
12949 Specify the time of the first frame that will be dropped, i.e. the frame
12950 immediately preceding the one with the timestamp @var{end} will be the last
12951 frame in the output.
12954 This is the same as @var{start}, except this option sets the start timestamp
12955 in timebase units instead of seconds.
12958 This is the same as @var{end}, except this option sets the end timestamp
12959 in timebase units instead of seconds.
12962 The maximum duration of the output in seconds.
12965 The number of the first frame that should be passed to the output.
12968 The number of the first frame that should be dropped.
12971 @option{start}, @option{end}, and @option{duration} are expressed as time
12972 duration specifications; see
12973 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
12974 for the accepted syntax.
12976 Note that the first two sets of the start/end options and the @option{duration}
12977 option look at the frame timestamp, while the _frame variants simply count the
12978 frames that pass through the filter. Also note that this filter does not modify
12979 the timestamps. If you wish for the output timestamps to start at zero, insert a
12980 setpts filter after the trim filter.
12982 If multiple start or end options are set, this filter tries to be greedy and
12983 keep all the frames that match at least one of the specified constraints. To keep
12984 only the part that matches all the constraints at once, chain multiple trim
12987 The defaults are such that all the input is kept. So it is possible to set e.g.
12988 just the end values to keep everything before the specified time.
12993 Drop everything except the second minute of input:
12995 ffmpeg -i INPUT -vf trim=60:120
12999 Keep only the first second:
13001 ffmpeg -i INPUT -vf trim=duration=1
13010 Sharpen or blur the input video.
13012 It accepts the following parameters:
13015 @item luma_msize_x, lx
13016 Set the luma matrix horizontal size. It must be an odd integer between
13017 3 and 63. The default value is 5.
13019 @item luma_msize_y, ly
13020 Set the luma matrix vertical size. It must be an odd integer between 3
13021 and 63. The default value is 5.
13023 @item luma_amount, la
13024 Set the luma effect strength. It must be a floating point number, reasonable
13025 values lay between -1.5 and 1.5.
13027 Negative values will blur the input video, while positive values will
13028 sharpen it, a value of zero will disable the effect.
13030 Default value is 1.0.
13032 @item chroma_msize_x, cx
13033 Set the chroma matrix horizontal size. It must be an odd integer
13034 between 3 and 63. The default value is 5.
13036 @item chroma_msize_y, cy
13037 Set the chroma matrix vertical size. It must be an odd integer
13038 between 3 and 63. The default value is 5.
13040 @item chroma_amount, ca
13041 Set the chroma effect strength. It must be a floating point number, reasonable
13042 values lay between -1.5 and 1.5.
13044 Negative values will blur the input video, while positive values will
13045 sharpen it, a value of zero will disable the effect.
13047 Default value is 0.0.
13050 If set to 1, specify using OpenCL capabilities, only available if
13051 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
13055 All parameters are optional and default to the equivalent of the
13056 string '5:5:1.0:5:5:0.0'.
13058 @subsection Examples
13062 Apply strong luma sharpen effect:
13064 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
13068 Apply a strong blur of both luma and chroma parameters:
13070 unsharp=7:7:-2:7:7:-2
13076 Apply ultra slow/simple postprocessing filter that compresses and decompresses
13077 the image at several (or - in the case of @option{quality} level @code{8} - all)
13078 shifts and average the results.
13080 The way this differs from the behavior of spp is that uspp actually encodes &
13081 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
13082 DCT similar to MJPEG.
13084 The filter accepts the following options:
13088 Set quality. This option defines the number of levels for averaging. It accepts
13089 an integer in the range 0-8. If set to @code{0}, the filter will have no
13090 effect. A value of @code{8} means the higher quality. For each increment of
13091 that value the speed drops by a factor of approximately 2. Default value is
13095 Force a constant quantization parameter. If not set, the filter will use the QP
13096 from the video stream (if available).
13099 @section vectorscope
13101 Display 2 color component values in the two dimensional graph (which is called
13104 This filter accepts the following options:
13108 Set vectorscope mode.
13110 It accepts the following values:
13113 Gray values are displayed on graph, higher brightness means more pixels have
13114 same component color value on location in graph. This is the default mode.
13117 Gray values are displayed on graph. Surrounding pixels values which are not
13118 present in video frame are drawn in gradient of 2 color components which are
13119 set by option @code{x} and @code{y}. The 3rd color component is static.
13122 Actual color components values present in video frame are displayed on graph.
13125 Similar as color2 but higher frequency of same values @code{x} and @code{y}
13126 on graph increases value of another color component, which is luminance by
13127 default values of @code{x} and @code{y}.
13130 Actual colors present in video frame are displayed on graph. If two different
13131 colors map to same position on graph then color with higher value of component
13132 not present in graph is picked.
13135 Gray values are displayed on graph. Similar to @code{color} but with 3rd color
13136 component picked from radial gradient.
13140 Set which color component will be represented on X-axis. Default is @code{1}.
13143 Set which color component will be represented on Y-axis. Default is @code{2}.
13146 Set intensity, used by modes: gray, color, color3 and color5 for increasing brightness
13147 of color component which represents frequency of (X, Y) location in graph.
13152 No envelope, this is default.
13155 Instant envelope, even darkest single pixel will be clearly highlighted.
13158 Hold maximum and minimum values presented in graph over time. This way you
13159 can still spot out of range values without constantly looking at vectorscope.
13162 Peak and instant envelope combined together.
13166 Set what kind of graticule to draw.
13174 Set graticule opacity.
13177 Set graticule flags.
13181 Draw graticule for white point.
13184 Draw graticule for black point.
13187 Draw color points short names.
13191 Set background opacity.
13193 @item lthreshold, l
13194 Set low threshold for color component not represented on X or Y axis.
13195 Values lower than this value will be ignored. Default is 0.
13196 Note this value is multiplied with actual max possible value one pixel component
13197 can have. So for 8-bit input and low threshold value of 0.1 actual threshold
13200 @item hthreshold, h
13201 Set high threshold for color component not represented on X or Y axis.
13202 Values higher than this value will be ignored. Default is 1.
13203 Note this value is multiplied with actual max possible value one pixel component
13204 can have. So for 8-bit input and high threshold value of 0.9 actual threshold
13205 is 0.9 * 255 = 230.
13207 @item colorspace, c
13208 Set what kind of colorspace to use when drawing graticule.
13217 @anchor{vidstabdetect}
13218 @section vidstabdetect
13220 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
13221 @ref{vidstabtransform} for pass 2.
13223 This filter generates a file with relative translation and rotation
13224 transform information about subsequent frames, which is then used by
13225 the @ref{vidstabtransform} filter.
13227 To enable compilation of this filter you need to configure FFmpeg with
13228 @code{--enable-libvidstab}.
13230 This filter accepts the following options:
13234 Set the path to the file used to write the transforms information.
13235 Default value is @file{transforms.trf}.
13238 Set how shaky the video is and how quick the camera is. It accepts an
13239 integer in the range 1-10, a value of 1 means little shakiness, a
13240 value of 10 means strong shakiness. Default value is 5.
13243 Set the accuracy of the detection process. It must be a value in the
13244 range 1-15. A value of 1 means low accuracy, a value of 15 means high
13245 accuracy. Default value is 15.
13248 Set stepsize of the search process. The region around minimum is
13249 scanned with 1 pixel resolution. Default value is 6.
13252 Set minimum contrast. Below this value a local measurement field is
13253 discarded. Must be a floating point value in the range 0-1. Default
13257 Set reference frame number for tripod mode.
13259 If enabled, the motion of the frames is compared to a reference frame
13260 in the filtered stream, identified by the specified number. The idea
13261 is to compensate all movements in a more-or-less static scene and keep
13262 the camera view absolutely still.
13264 If set to 0, it is disabled. The frames are counted starting from 1.
13267 Show fields and transforms in the resulting frames. It accepts an
13268 integer in the range 0-2. Default value is 0, which disables any
13272 @subsection Examples
13276 Use default values:
13282 Analyze strongly shaky movie and put the results in file
13283 @file{mytransforms.trf}:
13285 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
13289 Visualize the result of internal transformations in the resulting
13292 vidstabdetect=show=1
13296 Analyze a video with medium shakiness using @command{ffmpeg}:
13298 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
13302 @anchor{vidstabtransform}
13303 @section vidstabtransform
13305 Video stabilization/deshaking: pass 2 of 2,
13306 see @ref{vidstabdetect} for pass 1.
13308 Read a file with transform information for each frame and
13309 apply/compensate them. Together with the @ref{vidstabdetect}
13310 filter this can be used to deshake videos. See also
13311 @url{http://public.hronopik.de/vid.stab}. It is important to also use
13312 the @ref{unsharp} filter, see below.
13314 To enable compilation of this filter you need to configure FFmpeg with
13315 @code{--enable-libvidstab}.
13317 @subsection Options
13321 Set path to the file used to read the transforms. Default value is
13322 @file{transforms.trf}.
13325 Set the number of frames (value*2 + 1) used for lowpass filtering the
13326 camera movements. Default value is 10.
13328 For example a number of 10 means that 21 frames are used (10 in the
13329 past and 10 in the future) to smoothen the motion in the video. A
13330 larger value leads to a smoother video, but limits the acceleration of
13331 the camera (pan/tilt movements). 0 is a special case where a static
13332 camera is simulated.
13335 Set the camera path optimization algorithm.
13337 Accepted values are:
13340 gaussian kernel low-pass filter on camera motion (default)
13342 averaging on transformations
13346 Set maximal number of pixels to translate frames. Default value is -1,
13350 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
13351 value is -1, meaning no limit.
13354 Specify how to deal with borders that may be visible due to movement
13357 Available values are:
13360 keep image information from previous frame (default)
13362 fill the border black
13366 Invert transforms if set to 1. Default value is 0.
13369 Consider transforms as relative to previous frame if set to 1,
13370 absolute if set to 0. Default value is 0.
13373 Set percentage to zoom. A positive value will result in a zoom-in
13374 effect, a negative value in a zoom-out effect. Default value is 0 (no
13378 Set optimal zooming to avoid borders.
13380 Accepted values are:
13385 optimal static zoom value is determined (only very strong movements
13386 will lead to visible borders) (default)
13388 optimal adaptive zoom value is determined (no borders will be
13389 visible), see @option{zoomspeed}
13392 Note that the value given at zoom is added to the one calculated here.
13395 Set percent to zoom maximally each frame (enabled when
13396 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
13400 Specify type of interpolation.
13402 Available values are:
13407 linear only horizontal
13409 linear in both directions (default)
13411 cubic in both directions (slow)
13415 Enable virtual tripod mode if set to 1, which is equivalent to
13416 @code{relative=0:smoothing=0}. Default value is 0.
13418 Use also @code{tripod} option of @ref{vidstabdetect}.
13421 Increase log verbosity if set to 1. Also the detected global motions
13422 are written to the temporary file @file{global_motions.trf}. Default
13426 @subsection Examples
13430 Use @command{ffmpeg} for a typical stabilization with default values:
13432 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
13435 Note the use of the @ref{unsharp} filter which is always recommended.
13438 Zoom in a bit more and load transform data from a given file:
13440 vidstabtransform=zoom=5:input="mytransforms.trf"
13444 Smoothen the video even more:
13446 vidstabtransform=smoothing=30
13452 Flip the input video vertically.
13454 For example, to vertically flip a video with @command{ffmpeg}:
13456 ffmpeg -i in.avi -vf "vflip" out.avi
13462 Make or reverse a natural vignetting effect.
13464 The filter accepts the following options:
13468 Set lens angle expression as a number of radians.
13470 The value is clipped in the @code{[0,PI/2]} range.
13472 Default value: @code{"PI/5"}
13476 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
13480 Set forward/backward mode.
13482 Available modes are:
13485 The larger the distance from the central point, the darker the image becomes.
13488 The larger the distance from the central point, the brighter the image becomes.
13489 This can be used to reverse a vignette effect, though there is no automatic
13490 detection to extract the lens @option{angle} and other settings (yet). It can
13491 also be used to create a burning effect.
13494 Default value is @samp{forward}.
13497 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
13499 It accepts the following values:
13502 Evaluate expressions only once during the filter initialization.
13505 Evaluate expressions for each incoming frame. This is way slower than the
13506 @samp{init} mode since it requires all the scalers to be re-computed, but it
13507 allows advanced dynamic expressions.
13510 Default value is @samp{init}.
13513 Set dithering to reduce the circular banding effects. Default is @code{1}
13517 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
13518 Setting this value to the SAR of the input will make a rectangular vignetting
13519 following the dimensions of the video.
13521 Default is @code{1/1}.
13524 @subsection Expressions
13526 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
13527 following parameters.
13532 input width and height
13535 the number of input frame, starting from 0
13538 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
13539 @var{TB} units, NAN if undefined
13542 frame rate of the input video, NAN if the input frame rate is unknown
13545 the PTS (Presentation TimeStamp) of the filtered video frame,
13546 expressed in seconds, NAN if undefined
13549 time base of the input video
13553 @subsection Examples
13557 Apply simple strong vignetting effect:
13563 Make a flickering vignetting:
13565 vignette='PI/4+random(1)*PI/50':eval=frame
13571 Stack input videos vertically.
13573 All streams must be of same pixel format and of same width.
13575 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
13576 to create same output.
13578 The filter accept the following option:
13582 Set number of input streams. Default is 2.
13585 If set to 1, force the output to terminate when the shortest input
13586 terminates. Default value is 0.
13591 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
13592 Deinterlacing Filter").
13594 Based on the process described by Martin Weston for BBC R&D, and
13595 implemented based on the de-interlace algorithm written by Jim
13596 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
13597 uses filter coefficients calculated by BBC R&D.
13599 There are two sets of filter coefficients, so called "simple":
13600 and "complex". Which set of filter coefficients is used can
13601 be set by passing an optional parameter:
13605 Set the interlacing filter coefficients. Accepts one of the following values:
13609 Simple filter coefficient set.
13611 More-complex filter coefficient set.
13613 Default value is @samp{complex}.
13616 Specify which frames to deinterlace. Accept one of the following values:
13620 Deinterlace all frames,
13622 Only deinterlace frames marked as interlaced.
13625 Default value is @samp{all}.
13629 Video waveform monitor.
13631 The waveform monitor plots color component intensity. By default luminance
13632 only. Each column of the waveform corresponds to a column of pixels in the
13635 It accepts the following options:
13639 Can be either @code{row}, or @code{column}. Default is @code{column}.
13640 In row mode, the graph on the left side represents color component value 0 and
13641 the right side represents value = 255. In column mode, the top side represents
13642 color component value = 0 and bottom side represents value = 255.
13645 Set intensity. Smaller values are useful to find out how many values of the same
13646 luminance are distributed across input rows/columns.
13647 Default value is @code{0.04}. Allowed range is [0, 1].
13650 Set mirroring mode. @code{0} means unmirrored, @code{1} means mirrored.
13651 In mirrored mode, higher values will be represented on the left
13652 side for @code{row} mode and at the top for @code{column} mode. Default is
13653 @code{1} (mirrored).
13657 It accepts the following values:
13660 Presents information identical to that in the @code{parade}, except
13661 that the graphs representing color components are superimposed directly
13664 This display mode makes it easier to spot relative differences or similarities
13665 in overlapping areas of the color components that are supposed to be identical,
13666 such as neutral whites, grays, or blacks.
13669 Display separate graph for the color components side by side in
13670 @code{row} mode or one below the other in @code{column} mode.
13673 Display separate graph for the color components side by side in
13674 @code{column} mode or one below the other in @code{row} mode.
13676 Using this display mode makes it easy to spot color casts in the highlights
13677 and shadows of an image, by comparing the contours of the top and the bottom
13678 graphs of each waveform. Since whites, grays, and blacks are characterized
13679 by exactly equal amounts of red, green, and blue, neutral areas of the picture
13680 should display three waveforms of roughly equal width/height. If not, the
13681 correction is easy to perform by making level adjustments the three waveforms.
13683 Default is @code{stack}.
13685 @item components, c
13686 Set which color components to display. Default is 1, which means only luminance
13687 or red color component if input is in RGB colorspace. If is set for example to
13688 7 it will display all 3 (if) available color components.
13693 No envelope, this is default.
13696 Instant envelope, minimum and maximum values presented in graph will be easily
13697 visible even with small @code{step} value.
13700 Hold minimum and maximum values presented in graph across time. This way you
13701 can still spot out of range values without constantly looking at waveforms.
13704 Peak and instant envelope combined together.
13710 No filtering, this is default.
13713 Luma and chroma combined together.
13716 Similar as above, but shows difference between blue and red chroma.
13719 Displays only chroma.
13722 Displays actual color value on waveform.
13725 Similar as above, but with luma showing frequency of chroma values.
13729 Set which graticule to display.
13733 Do not display graticule.
13736 Display green graticule showing legal broadcast ranges.
13740 Set graticule opacity.
13743 Set graticule flags.
13747 Draw numbers above lines. By default enabled.
13750 Draw dots instead of lines.
13754 Set scale used for displaying graticule.
13761 Default is digital.
13765 Apply the xBR high-quality magnification filter which is designed for pixel
13766 art. It follows a set of edge-detection rules, see
13767 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
13769 It accepts the following option:
13773 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
13774 @code{3xBR} and @code{4} for @code{4xBR}.
13775 Default is @code{3}.
13781 Deinterlace the input video ("yadif" means "yet another deinterlacing
13784 It accepts the following parameters:
13790 The interlacing mode to adopt. It accepts one of the following values:
13793 @item 0, send_frame
13794 Output one frame for each frame.
13795 @item 1, send_field
13796 Output one frame for each field.
13797 @item 2, send_frame_nospatial
13798 Like @code{send_frame}, but it skips the spatial interlacing check.
13799 @item 3, send_field_nospatial
13800 Like @code{send_field}, but it skips the spatial interlacing check.
13803 The default value is @code{send_frame}.
13806 The picture field parity assumed for the input interlaced video. It accepts one
13807 of the following values:
13811 Assume the top field is first.
13813 Assume the bottom field is first.
13815 Enable automatic detection of field parity.
13818 The default value is @code{auto}.
13819 If the interlacing is unknown or the decoder does not export this information,
13820 top field first will be assumed.
13823 Specify which frames to deinterlace. Accept one of the following
13828 Deinterlace all frames.
13829 @item 1, interlaced
13830 Only deinterlace frames marked as interlaced.
13833 The default value is @code{all}.
13838 Apply Zoom & Pan effect.
13840 This filter accepts the following options:
13844 Set the zoom expression. Default is 1.
13848 Set the x and y expression. Default is 0.
13851 Set the duration expression in number of frames.
13852 This sets for how many number of frames effect will last for
13853 single input image.
13856 Set the output image size, default is 'hd720'.
13859 Set the output frame rate, default is '25'.
13862 Each expression can contain the following constants:
13881 Output frame count.
13885 Last calculated 'x' and 'y' position from 'x' and 'y' expression
13886 for current input frame.
13890 'x' and 'y' of last output frame of previous input frame or 0 when there was
13891 not yet such frame (first input frame).
13894 Last calculated zoom from 'z' expression for current input frame.
13897 Last calculated zoom of last output frame of previous input frame.
13900 Number of output frames for current input frame. Calculated from 'd' expression
13901 for each input frame.
13904 number of output frames created for previous input frame
13907 Rational number: input width / input height
13910 sample aspect ratio
13913 display aspect ratio
13917 @subsection Examples
13921 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
13923 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
13927 Zoom-in up to 1.5 and pan always at center of picture:
13929 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
13934 Scale (resize) the input video, using the z.lib library:
13935 https://github.com/sekrit-twc/zimg.
13937 The zscale filter forces the output display aspect ratio to be the same
13938 as the input, by changing the output sample aspect ratio.
13940 If the input image format is different from the format requested by
13941 the next filter, the zscale filter will convert the input to the
13944 @subsection Options
13945 The filter accepts the following options.
13950 Set the output video dimension expression. Default value is the input
13953 If the @var{width} or @var{w} is 0, the input width is used for the output.
13954 If the @var{height} or @var{h} is 0, the input height is used for the output.
13956 If one of the values is -1, the zscale filter will use a value that
13957 maintains the aspect ratio of the input image, calculated from the
13958 other specified dimension. If both of them are -1, the input size is
13961 If one of the values is -n with n > 1, the zscale filter will also use a value
13962 that maintains the aspect ratio of the input image, calculated from the other
13963 specified dimension. After that it will, however, make sure that the calculated
13964 dimension is divisible by n and adjust the value if necessary.
13966 See below for the list of accepted constants for use in the dimension
13970 Set the video size. For the syntax of this option, check the
13971 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13974 Set the dither type.
13976 Possible values are:
13981 @item error_diffusion
13987 Set the resize filter type.
13989 Possible values are:
13999 Default is bilinear.
14002 Set the color range.
14004 Possible values are:
14011 Default is same as input.
14014 Set the color primaries.
14016 Possible values are:
14026 Default is same as input.
14029 Set the transfer characteristics.
14031 Possible values are:
14042 Default is same as input.
14045 Set the colorspace matrix.
14047 Possible value are:
14058 Default is same as input.
14061 Set the input color range.
14063 Possible values are:
14070 Default is same as input.
14072 @item primariesin, pin
14073 Set the input color primaries.
14075 Possible values are:
14085 Default is same as input.
14087 @item transferin, tin
14088 Set the input transfer characteristics.
14090 Possible values are:
14101 Default is same as input.
14103 @item matrixin, min
14104 Set the input colorspace matrix.
14106 Possible value are:
14118 The values of the @option{w} and @option{h} options are expressions
14119 containing the following constants:
14124 The input width and height
14128 These are the same as @var{in_w} and @var{in_h}.
14132 The output (scaled) width and height
14136 These are the same as @var{out_w} and @var{out_h}
14139 The same as @var{iw} / @var{ih}
14142 input sample aspect ratio
14145 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
14149 horizontal and vertical input chroma subsample values. For example for the
14150 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
14154 horizontal and vertical output chroma subsample values. For example for the
14155 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
14161 @c man end VIDEO FILTERS
14163 @chapter Video Sources
14164 @c man begin VIDEO SOURCES
14166 Below is a description of the currently available video sources.
14170 Buffer video frames, and make them available to the filter chain.
14172 This source is mainly intended for a programmatic use, in particular
14173 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
14175 It accepts the following parameters:
14180 Specify the size (width and height) of the buffered video frames. For the
14181 syntax of this option, check the
14182 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14185 The input video width.
14188 The input video height.
14191 A string representing the pixel format of the buffered video frames.
14192 It may be a number corresponding to a pixel format, or a pixel format
14196 Specify the timebase assumed by the timestamps of the buffered frames.
14199 Specify the frame rate expected for the video stream.
14201 @item pixel_aspect, sar
14202 The sample (pixel) aspect ratio of the input video.
14205 Specify the optional parameters to be used for the scale filter which
14206 is automatically inserted when an input change is detected in the
14207 input size or format.
14209 @item hw_frames_ctx
14210 When using a hardware pixel format, this should be a reference to an
14211 AVHWFramesContext describing input frames.
14216 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
14219 will instruct the source to accept video frames with size 320x240 and
14220 with format "yuv410p", assuming 1/24 as the timestamps timebase and
14221 square pixels (1:1 sample aspect ratio).
14222 Since the pixel format with name "yuv410p" corresponds to the number 6
14223 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
14224 this example corresponds to:
14226 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
14229 Alternatively, the options can be specified as a flat string, but this
14230 syntax is deprecated:
14232 @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}]
14236 Create a pattern generated by an elementary cellular automaton.
14238 The initial state of the cellular automaton can be defined through the
14239 @option{filename}, and @option{pattern} options. If such options are
14240 not specified an initial state is created randomly.
14242 At each new frame a new row in the video is filled with the result of
14243 the cellular automaton next generation. The behavior when the whole
14244 frame is filled is defined by the @option{scroll} option.
14246 This source accepts the following options:
14250 Read the initial cellular automaton state, i.e. the starting row, from
14251 the specified file.
14252 In the file, each non-whitespace character is considered an alive
14253 cell, a newline will terminate the row, and further characters in the
14254 file will be ignored.
14257 Read the initial cellular automaton state, i.e. the starting row, from
14258 the specified string.
14260 Each non-whitespace character in the string is considered an alive
14261 cell, a newline will terminate the row, and further characters in the
14262 string will be ignored.
14265 Set the video rate, that is the number of frames generated per second.
14268 @item random_fill_ratio, ratio
14269 Set the random fill ratio for the initial cellular automaton row. It
14270 is a floating point number value ranging from 0 to 1, defaults to
14273 This option is ignored when a file or a pattern is specified.
14275 @item random_seed, seed
14276 Set the seed for filling randomly the initial row, must be an integer
14277 included between 0 and UINT32_MAX. If not specified, or if explicitly
14278 set to -1, the filter will try to use a good random seed on a best
14282 Set the cellular automaton rule, it is a number ranging from 0 to 255.
14283 Default value is 110.
14286 Set the size of the output video. For the syntax of this option, check the
14287 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14289 If @option{filename} or @option{pattern} is specified, the size is set
14290 by default to the width of the specified initial state row, and the
14291 height is set to @var{width} * PHI.
14293 If @option{size} is set, it must contain the width of the specified
14294 pattern string, and the specified pattern will be centered in the
14297 If a filename or a pattern string is not specified, the size value
14298 defaults to "320x518" (used for a randomly generated initial state).
14301 If set to 1, scroll the output upward when all the rows in the output
14302 have been already filled. If set to 0, the new generated row will be
14303 written over the top row just after the bottom row is filled.
14306 @item start_full, full
14307 If set to 1, completely fill the output with generated rows before
14308 outputting the first frame.
14309 This is the default behavior, for disabling set the value to 0.
14312 If set to 1, stitch the left and right row edges together.
14313 This is the default behavior, for disabling set the value to 0.
14316 @subsection Examples
14320 Read the initial state from @file{pattern}, and specify an output of
14323 cellauto=f=pattern:s=200x400
14327 Generate a random initial row with a width of 200 cells, with a fill
14330 cellauto=ratio=2/3:s=200x200
14334 Create a pattern generated by rule 18 starting by a single alive cell
14335 centered on an initial row with width 100:
14337 cellauto=p=@@:s=100x400:full=0:rule=18
14341 Specify a more elaborated initial pattern:
14343 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
14348 @anchor{coreimagesrc}
14349 @section coreimagesrc
14350 Video source generated on GPU using Apple's CoreImage API on OSX.
14352 This video source is a specialized version of the @ref{coreimage} video filter.
14353 Use a core image generator at the beginning of the applied filterchain to
14354 generate the content.
14356 The coreimagesrc video source accepts the following options:
14358 @item list_generators
14359 List all available generators along with all their respective options as well as
14360 possible minimum and maximum values along with the default values.
14362 list_generators=true
14366 Specify the size of the sourced video. For the syntax of this option, check the
14367 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14368 The default value is @code{320x240}.
14371 Specify the frame rate of the sourced video, as the number of frames
14372 generated per second. It has to be a string in the format
14373 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
14374 number or a valid video frame rate abbreviation. The default value is
14378 Set the sample aspect ratio of the sourced video.
14381 Set the duration of the sourced video. See
14382 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
14383 for the accepted syntax.
14385 If not specified, or the expressed duration is negative, the video is
14386 supposed to be generated forever.
14389 Additionally, all options of the @ref{coreimage} video filter are accepted.
14390 A complete filterchain can be used for further processing of the
14391 generated input without CPU-HOST transfer. See @ref{coreimage} documentation
14392 and examples for details.
14394 @subsection Examples
14399 Use CIQRCodeGenerator to create a QR code for the FFmpeg homepage,
14400 given as complete and escaped command-line for Apple's standard bash shell:
14402 ffmpeg -f lavfi -i coreimagesrc=s=100x100:filter=CIQRCodeGenerator@@inputMessage=https\\\\\://FFmpeg.org/@@inputCorrectionLevel=H -frames:v 1 QRCode.png
14404 This example is equivalent to the QRCode example of @ref{coreimage} without the
14405 need for a nullsrc video source.
14409 @section mandelbrot
14411 Generate a Mandelbrot set fractal, and progressively zoom towards the
14412 point specified with @var{start_x} and @var{start_y}.
14414 This source accepts the following options:
14419 Set the terminal pts value. Default value is 400.
14422 Set the terminal scale value.
14423 Must be a floating point value. Default value is 0.3.
14426 Set the inner coloring mode, that is the algorithm used to draw the
14427 Mandelbrot fractal internal region.
14429 It shall assume one of the following values:
14434 Show time until convergence.
14436 Set color based on point closest to the origin of the iterations.
14441 Default value is @var{mincol}.
14444 Set the bailout value. Default value is 10.0.
14447 Set the maximum of iterations performed by the rendering
14448 algorithm. Default value is 7189.
14451 Set outer coloring mode.
14452 It shall assume one of following values:
14454 @item iteration_count
14455 Set iteration cound mode.
14456 @item normalized_iteration_count
14457 set normalized iteration count mode.
14459 Default value is @var{normalized_iteration_count}.
14462 Set frame rate, expressed as number of frames per second. Default
14466 Set frame size. For the syntax of this option, check the "Video
14467 size" section in the ffmpeg-utils manual. Default value is "640x480".
14470 Set the initial scale value. Default value is 3.0.
14473 Set the initial x position. Must be a floating point value between
14474 -100 and 100. Default value is -0.743643887037158704752191506114774.
14477 Set the initial y position. Must be a floating point value between
14478 -100 and 100. Default value is -0.131825904205311970493132056385139.
14483 Generate various test patterns, as generated by the MPlayer test filter.
14485 The size of the generated video is fixed, and is 256x256.
14486 This source is useful in particular for testing encoding features.
14488 This source accepts the following options:
14493 Specify the frame rate of the sourced video, as the number of frames
14494 generated per second. It has to be a string in the format
14495 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
14496 number or a valid video frame rate abbreviation. The default value is
14500 Set the duration of the sourced video. See
14501 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
14502 for the accepted syntax.
14504 If not specified, or the expressed duration is negative, the video is
14505 supposed to be generated forever.
14509 Set the number or the name of the test to perform. Supported tests are:
14525 Default value is "all", which will cycle through the list of all tests.
14530 mptestsrc=t=dc_luma
14533 will generate a "dc_luma" test pattern.
14535 @section frei0r_src
14537 Provide a frei0r source.
14539 To enable compilation of this filter you need to install the frei0r
14540 header and configure FFmpeg with @code{--enable-frei0r}.
14542 This source accepts the following parameters:
14547 The size of the video to generate. For the syntax of this option, check the
14548 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14551 The framerate of the generated video. It may be a string of the form
14552 @var{num}/@var{den} or a frame rate abbreviation.
14555 The name to the frei0r source to load. For more information regarding frei0r and
14556 how to set the parameters, read the @ref{frei0r} section in the video filters
14559 @item filter_params
14560 A '|'-separated list of parameters to pass to the frei0r source.
14564 For example, to generate a frei0r partik0l source with size 200x200
14565 and frame rate 10 which is overlaid on the overlay filter main input:
14567 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
14572 Generate a life pattern.
14574 This source is based on a generalization of John Conway's life game.
14576 The sourced input represents a life grid, each pixel represents a cell
14577 which can be in one of two possible states, alive or dead. Every cell
14578 interacts with its eight neighbours, which are the cells that are
14579 horizontally, vertically, or diagonally adjacent.
14581 At each interaction the grid evolves according to the adopted rule,
14582 which specifies the number of neighbor alive cells which will make a
14583 cell stay alive or born. The @option{rule} option allows one to specify
14586 This source accepts the following options:
14590 Set the file from which to read the initial grid state. In the file,
14591 each non-whitespace character is considered an alive cell, and newline
14592 is used to delimit the end of each row.
14594 If this option is not specified, the initial grid is generated
14598 Set the video rate, that is the number of frames generated per second.
14601 @item random_fill_ratio, ratio
14602 Set the random fill ratio for the initial random grid. It is a
14603 floating point number value ranging from 0 to 1, defaults to 1/PHI.
14604 It is ignored when a file is specified.
14606 @item random_seed, seed
14607 Set the seed for filling the initial random grid, must be an integer
14608 included between 0 and UINT32_MAX. If not specified, or if explicitly
14609 set to -1, the filter will try to use a good random seed on a best
14615 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
14616 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
14617 @var{NS} specifies the number of alive neighbor cells which make a
14618 live cell stay alive, and @var{NB} the number of alive neighbor cells
14619 which make a dead cell to become alive (i.e. to "born").
14620 "s" and "b" can be used in place of "S" and "B", respectively.
14622 Alternatively a rule can be specified by an 18-bits integer. The 9
14623 high order bits are used to encode the next cell state if it is alive
14624 for each number of neighbor alive cells, the low order bits specify
14625 the rule for "borning" new cells. Higher order bits encode for an
14626 higher number of neighbor cells.
14627 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
14628 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
14630 Default value is "S23/B3", which is the original Conway's game of life
14631 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
14632 cells, and will born a new cell if there are three alive cells around
14636 Set the size of the output video. For the syntax of this option, check the
14637 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14639 If @option{filename} is specified, the size is set by default to the
14640 same size of the input file. If @option{size} is set, it must contain
14641 the size specified in the input file, and the initial grid defined in
14642 that file is centered in the larger resulting area.
14644 If a filename is not specified, the size value defaults to "320x240"
14645 (used for a randomly generated initial grid).
14648 If set to 1, stitch the left and right grid edges together, and the
14649 top and bottom edges also. Defaults to 1.
14652 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
14653 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
14654 value from 0 to 255.
14657 Set the color of living (or new born) cells.
14660 Set the color of dead cells. If @option{mold} is set, this is the first color
14661 used to represent a dead cell.
14664 Set mold color, for definitely dead and moldy cells.
14666 For the syntax of these 3 color options, check the "Color" section in the
14667 ffmpeg-utils manual.
14670 @subsection Examples
14674 Read a grid from @file{pattern}, and center it on a grid of size
14677 life=f=pattern:s=300x300
14681 Generate a random grid of size 200x200, with a fill ratio of 2/3:
14683 life=ratio=2/3:s=200x200
14687 Specify a custom rule for evolving a randomly generated grid:
14693 Full example with slow death effect (mold) using @command{ffplay}:
14695 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
14702 @anchor{haldclutsrc}
14704 @anchor{rgbtestsrc}
14706 @anchor{smptehdbars}
14709 @section allrgb, allyuv, color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc, testsrc2
14711 The @code{allrgb} source returns frames of size 4096x4096 of all rgb colors.
14713 The @code{allyuv} source returns frames of size 4096x4096 of all yuv colors.
14715 The @code{color} source provides an uniformly colored input.
14717 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
14718 @ref{haldclut} filter.
14720 The @code{nullsrc} source returns unprocessed video frames. It is
14721 mainly useful to be employed in analysis / debugging tools, or as the
14722 source for filters which ignore the input data.
14724 The @code{rgbtestsrc} source generates an RGB test pattern useful for
14725 detecting RGB vs BGR issues. You should see a red, green and blue
14726 stripe from top to bottom.
14728 The @code{smptebars} source generates a color bars pattern, based on
14729 the SMPTE Engineering Guideline EG 1-1990.
14731 The @code{smptehdbars} source generates a color bars pattern, based on
14732 the SMPTE RP 219-2002.
14734 The @code{testsrc} source generates a test video pattern, showing a
14735 color pattern, a scrolling gradient and a timestamp. This is mainly
14736 intended for testing purposes.
14738 The @code{testsrc2} source is similar to testsrc, but supports more
14739 pixel formats instead of just @code{rgb24}. This allows using it as an
14740 input for other tests without requiring a format conversion.
14742 The sources accept the following parameters:
14747 Specify the color of the source, only available in the @code{color}
14748 source. For the syntax of this option, check the "Color" section in the
14749 ffmpeg-utils manual.
14752 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
14753 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
14754 pixels to be used as identity matrix for 3D lookup tables. Each component is
14755 coded on a @code{1/(N*N)} scale.
14758 Specify the size of the sourced video. For the syntax of this option, check the
14759 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14760 The default value is @code{320x240}.
14762 This option is not available with the @code{haldclutsrc} filter.
14765 Specify the frame rate of the sourced video, as the number of frames
14766 generated per second. It has to be a string in the format
14767 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
14768 number or a valid video frame rate abbreviation. The default value is
14772 Set the sample aspect ratio of the sourced video.
14775 Set the duration of the sourced video. See
14776 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
14777 for the accepted syntax.
14779 If not specified, or the expressed duration is negative, the video is
14780 supposed to be generated forever.
14783 Set the number of decimals to show in the timestamp, only available in the
14784 @code{testsrc} source.
14786 The displayed timestamp value will correspond to the original
14787 timestamp value multiplied by the power of 10 of the specified
14788 value. Default value is 0.
14791 For example the following:
14793 testsrc=duration=5.3:size=qcif:rate=10
14796 will generate a video with a duration of 5.3 seconds, with size
14797 176x144 and a frame rate of 10 frames per second.
14799 The following graph description will generate a red source
14800 with an opacity of 0.2, with size "qcif" and a frame rate of 10
14803 color=c=red@@0.2:s=qcif:r=10
14806 If the input content is to be ignored, @code{nullsrc} can be used. The
14807 following command generates noise in the luminance plane by employing
14808 the @code{geq} filter:
14810 nullsrc=s=256x256, geq=random(1)*255:128:128
14813 @subsection Commands
14815 The @code{color} source supports the following commands:
14819 Set the color of the created image. Accepts the same syntax of the
14820 corresponding @option{color} option.
14823 @c man end VIDEO SOURCES
14825 @chapter Video Sinks
14826 @c man begin VIDEO SINKS
14828 Below is a description of the currently available video sinks.
14830 @section buffersink
14832 Buffer video frames, and make them available to the end of the filter
14835 This sink is mainly intended for programmatic use, in particular
14836 through the interface defined in @file{libavfilter/buffersink.h}
14837 or the options system.
14839 It accepts a pointer to an AVBufferSinkContext structure, which
14840 defines the incoming buffers' formats, to be passed as the opaque
14841 parameter to @code{avfilter_init_filter} for initialization.
14845 Null video sink: do absolutely nothing with the input video. It is
14846 mainly useful as a template and for use in analysis / debugging
14849 @c man end VIDEO SINKS
14851 @chapter Multimedia Filters
14852 @c man begin MULTIMEDIA FILTERS
14854 Below is a description of the currently available multimedia filters.
14856 @section ahistogram
14858 Convert input audio to a video output, displaying the volume histogram.
14860 The filter accepts the following options:
14864 Specify how histogram is calculated.
14866 It accepts the following values:
14869 Use single histogram for all channels.
14871 Use separate histogram for each channel.
14873 Default is @code{single}.
14876 Set frame rate, expressed as number of frames per second. Default
14880 Specify the video size for the output. For the syntax of this option, check the
14881 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14882 Default value is @code{hd720}.
14887 It accepts the following values:
14898 reverse logarithmic
14900 Default is @code{log}.
14903 Set amplitude scale.
14905 It accepts the following values:
14912 Default is @code{log}.
14915 Set how much frames to accumulate in histogram.
14916 Defauls is 1. Setting this to -1 accumulates all frames.
14919 Set histogram ratio of window height.
14922 Set sonogram sliding.
14924 It accepts the following values:
14927 replace old rows with new ones.
14929 scroll from top to bottom.
14931 Default is @code{replace}.
14934 @section aphasemeter
14936 Convert input audio to a video output, displaying the audio phase.
14938 The filter accepts the following options:
14942 Set the output frame rate. Default value is @code{25}.
14945 Set the video size for the output. For the syntax of this option, check the
14946 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14947 Default value is @code{800x400}.
14952 Specify the red, green, blue contrast. Default values are @code{2},
14953 @code{7} and @code{1}.
14954 Allowed range is @code{[0, 255]}.
14957 Set color which will be used for drawing median phase. If color is
14958 @code{none} which is default, no median phase value will be drawn.
14961 The filter also exports the frame metadata @code{lavfi.aphasemeter.phase} which
14962 represents mean phase of current audio frame. Value is in range @code{[-1, 1]}.
14963 The @code{-1} means left and right channels are completely out of phase and
14964 @code{1} means channels are in phase.
14966 @section avectorscope
14968 Convert input audio to a video output, representing the audio vector
14971 The filter is used to measure the difference between channels of stereo
14972 audio stream. A monoaural signal, consisting of identical left and right
14973 signal, results in straight vertical line. Any stereo separation is visible
14974 as a deviation from this line, creating a Lissajous figure.
14975 If the straight (or deviation from it) but horizontal line appears this
14976 indicates that the left and right channels are out of phase.
14978 The filter accepts the following options:
14982 Set the vectorscope mode.
14984 Available values are:
14987 Lissajous rotated by 45 degrees.
14990 Same as above but not rotated.
14993 Shape resembling half of circle.
14996 Default value is @samp{lissajous}.
14999 Set the video size for the output. For the syntax of this option, check the
15000 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15001 Default value is @code{400x400}.
15004 Set the output frame rate. Default value is @code{25}.
15010 Specify the red, green, blue and alpha contrast. Default values are @code{40},
15011 @code{160}, @code{80} and @code{255}.
15012 Allowed range is @code{[0, 255]}.
15018 Specify the red, green, blue and alpha fade. Default values are @code{15},
15019 @code{10}, @code{5} and @code{5}.
15020 Allowed range is @code{[0, 255]}.
15023 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
15026 Set the vectorscope drawing mode.
15028 Available values are:
15031 Draw dot for each sample.
15034 Draw line between previous and current sample.
15037 Default value is @samp{dot}.
15040 @subsection Examples
15044 Complete example using @command{ffplay}:
15046 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
15047 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
15051 @section bench, abench
15053 Benchmark part of a filtergraph.
15055 The filter accepts the following options:
15059 Start or stop a timer.
15061 Available values are:
15064 Get the current time, set it as frame metadata (using the key
15065 @code{lavfi.bench.start_time}), and forward the frame to the next filter.
15068 Get the current time and fetch the @code{lavfi.bench.start_time} metadata from
15069 the input frame metadata to get the time difference. Time difference, average,
15070 maximum and minimum time (respectively @code{t}, @code{avg}, @code{max} and
15071 @code{min}) are then printed. The timestamps are expressed in seconds.
15075 @subsection Examples
15079 Benchmark @ref{selectivecolor} filter:
15081 bench=start,selectivecolor=reds=-.2 .12 -.49,bench=stop
15087 Concatenate audio and video streams, joining them together one after the
15090 The filter works on segments of synchronized video and audio streams. All
15091 segments must have the same number of streams of each type, and that will
15092 also be the number of streams at output.
15094 The filter accepts the following options:
15099 Set the number of segments. Default is 2.
15102 Set the number of output video streams, that is also the number of video
15103 streams in each segment. Default is 1.
15106 Set the number of output audio streams, that is also the number of audio
15107 streams in each segment. Default is 0.
15110 Activate unsafe mode: do not fail if segments have a different format.
15114 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
15115 @var{a} audio outputs.
15117 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
15118 segment, in the same order as the outputs, then the inputs for the second
15121 Related streams do not always have exactly the same duration, for various
15122 reasons including codec frame size or sloppy authoring. For that reason,
15123 related synchronized streams (e.g. a video and its audio track) should be
15124 concatenated at once. The concat filter will use the duration of the longest
15125 stream in each segment (except the last one), and if necessary pad shorter
15126 audio streams with silence.
15128 For this filter to work correctly, all segments must start at timestamp 0.
15130 All corresponding streams must have the same parameters in all segments; the
15131 filtering system will automatically select a common pixel format for video
15132 streams, and a common sample format, sample rate and channel layout for
15133 audio streams, but other settings, such as resolution, must be converted
15134 explicitly by the user.
15136 Different frame rates are acceptable but will result in variable frame rate
15137 at output; be sure to configure the output file to handle it.
15139 @subsection Examples
15143 Concatenate an opening, an episode and an ending, all in bilingual version
15144 (video in stream 0, audio in streams 1 and 2):
15146 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
15147 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
15148 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
15149 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
15153 Concatenate two parts, handling audio and video separately, using the
15154 (a)movie sources, and adjusting the resolution:
15156 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
15157 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
15158 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
15160 Note that a desync will happen at the stitch if the audio and video streams
15161 do not have exactly the same duration in the first file.
15168 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
15169 it unchanged. By default, it logs a message at a frequency of 10Hz with the
15170 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
15171 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
15173 The filter also has a video output (see the @var{video} option) with a real
15174 time graph to observe the loudness evolution. The graphic contains the logged
15175 message mentioned above, so it is not printed anymore when this option is set,
15176 unless the verbose logging is set. The main graphing area contains the
15177 short-term loudness (3 seconds of analysis), and the gauge on the right is for
15178 the momentary loudness (400 milliseconds).
15180 More information about the Loudness Recommendation EBU R128 on
15181 @url{http://tech.ebu.ch/loudness}.
15183 The filter accepts the following options:
15188 Activate the video output. The audio stream is passed unchanged whether this
15189 option is set or no. The video stream will be the first output stream if
15190 activated. Default is @code{0}.
15193 Set the video size. This option is for video only. For the syntax of this
15195 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15196 Default and minimum resolution is @code{640x480}.
15199 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
15200 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
15201 other integer value between this range is allowed.
15204 Set metadata injection. If set to @code{1}, the audio input will be segmented
15205 into 100ms output frames, each of them containing various loudness information
15206 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
15208 Default is @code{0}.
15211 Force the frame logging level.
15213 Available values are:
15216 information logging level
15218 verbose logging level
15221 By default, the logging level is set to @var{info}. If the @option{video} or
15222 the @option{metadata} options are set, it switches to @var{verbose}.
15227 Available modes can be cumulated (the option is a @code{flag} type). Possible
15231 Disable any peak mode (default).
15233 Enable sample-peak mode.
15235 Simple peak mode looking for the higher sample value. It logs a message
15236 for sample-peak (identified by @code{SPK}).
15238 Enable true-peak mode.
15240 If enabled, the peak lookup is done on an over-sampled version of the input
15241 stream for better peak accuracy. It logs a message for true-peak.
15242 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
15243 This mode requires a build with @code{libswresample}.
15247 Treat mono input files as "dual mono". If a mono file is intended for playback
15248 on a stereo system, its EBU R128 measurement will be perceptually incorrect.
15249 If set to @code{true}, this option will compensate for this effect.
15250 Multi-channel input files are not affected by this option.
15253 Set a specific pan law to be used for the measurement of dual mono files.
15254 This parameter is optional, and has a default value of -3.01dB.
15257 @subsection Examples
15261 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
15263 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
15267 Run an analysis with @command{ffmpeg}:
15269 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
15273 @section interleave, ainterleave
15275 Temporally interleave frames from several inputs.
15277 @code{interleave} works with video inputs, @code{ainterleave} with audio.
15279 These filters read frames from several inputs and send the oldest
15280 queued frame to the output.
15282 Input streams must have a well defined, monotonically increasing frame
15285 In order to submit one frame to output, these filters need to enqueue
15286 at least one frame for each input, so they cannot work in case one
15287 input is not yet terminated and will not receive incoming frames.
15289 For example consider the case when one input is a @code{select} filter
15290 which always drop input frames. The @code{interleave} filter will keep
15291 reading from that input, but it will never be able to send new frames
15292 to output until the input will send an end-of-stream signal.
15294 Also, depending on inputs synchronization, the filters will drop
15295 frames in case one input receives more frames than the other ones, and
15296 the queue is already filled.
15298 These filters accept the following options:
15302 Set the number of different inputs, it is 2 by default.
15305 @subsection Examples
15309 Interleave frames belonging to different streams using @command{ffmpeg}:
15311 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
15315 Add flickering blur effect:
15317 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
15321 @section perms, aperms
15323 Set read/write permissions for the output frames.
15325 These filters are mainly aimed at developers to test direct path in the
15326 following filter in the filtergraph.
15328 The filters accept the following options:
15332 Select the permissions mode.
15334 It accepts the following values:
15337 Do nothing. This is the default.
15339 Set all the output frames read-only.
15341 Set all the output frames directly writable.
15343 Make the frame read-only if writable, and writable if read-only.
15345 Set each output frame read-only or writable randomly.
15349 Set the seed for the @var{random} mode, must be an integer included between
15350 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
15351 @code{-1}, the filter will try to use a good random seed on a best effort
15355 Note: in case of auto-inserted filter between the permission filter and the
15356 following one, the permission might not be received as expected in that
15357 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
15358 perms/aperms filter can avoid this problem.
15360 @section realtime, arealtime
15362 Slow down filtering to match real time approximatively.
15364 These filters will pause the filtering for a variable amount of time to
15365 match the output rate with the input timestamps.
15366 They are similar to the @option{re} option to @code{ffmpeg}.
15368 They accept the following options:
15372 Time limit for the pauses. Any pause longer than that will be considered
15373 a timestamp discontinuity and reset the timer. Default is 2 seconds.
15376 @section select, aselect
15378 Select frames to pass in output.
15380 This filter accepts the following options:
15385 Set expression, which is evaluated for each input frame.
15387 If the expression is evaluated to zero, the frame is discarded.
15389 If the evaluation result is negative or NaN, the frame is sent to the
15390 first output; otherwise it is sent to the output with index
15391 @code{ceil(val)-1}, assuming that the input index starts from 0.
15393 For example a value of @code{1.2} corresponds to the output with index
15394 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
15397 Set the number of outputs. The output to which to send the selected
15398 frame is based on the result of the evaluation. Default value is 1.
15401 The expression can contain the following constants:
15405 The (sequential) number of the filtered frame, starting from 0.
15408 The (sequential) number of the selected frame, starting from 0.
15410 @item prev_selected_n
15411 The sequential number of the last selected frame. It's NAN if undefined.
15414 The timebase of the input timestamps.
15417 The PTS (Presentation TimeStamp) of the filtered video frame,
15418 expressed in @var{TB} units. It's NAN if undefined.
15421 The PTS of the filtered video frame,
15422 expressed in seconds. It's NAN if undefined.
15425 The PTS of the previously filtered video frame. It's NAN if undefined.
15427 @item prev_selected_pts
15428 The PTS of the last previously filtered video frame. It's NAN if undefined.
15430 @item prev_selected_t
15431 The PTS of the last previously selected video frame. It's NAN if undefined.
15434 The PTS of the first video frame in the video. It's NAN if undefined.
15437 The time of the first video frame in the video. It's NAN if undefined.
15439 @item pict_type @emph{(video only)}
15440 The type of the filtered frame. It can assume one of the following
15452 @item interlace_type @emph{(video only)}
15453 The frame interlace type. It can assume one of the following values:
15456 The frame is progressive (not interlaced).
15458 The frame is top-field-first.
15460 The frame is bottom-field-first.
15463 @item consumed_sample_n @emph{(audio only)}
15464 the number of selected samples before the current frame
15466 @item samples_n @emph{(audio only)}
15467 the number of samples in the current frame
15469 @item sample_rate @emph{(audio only)}
15470 the input sample rate
15473 This is 1 if the filtered frame is a key-frame, 0 otherwise.
15476 the position in the file of the filtered frame, -1 if the information
15477 is not available (e.g. for synthetic video)
15479 @item scene @emph{(video only)}
15480 value between 0 and 1 to indicate a new scene; a low value reflects a low
15481 probability for the current frame to introduce a new scene, while a higher
15482 value means the current frame is more likely to be one (see the example below)
15484 @item concatdec_select
15485 The concat demuxer can select only part of a concat input file by setting an
15486 inpoint and an outpoint, but the output packets may not be entirely contained
15487 in the selected interval. By using this variable, it is possible to skip frames
15488 generated by the concat demuxer which are not exactly contained in the selected
15491 This works by comparing the frame pts against the @var{lavf.concat.start_time}
15492 and the @var{lavf.concat.duration} packet metadata values which are also
15493 present in the decoded frames.
15495 The @var{concatdec_select} variable is -1 if the frame pts is at least
15496 start_time and either the duration metadata is missing or the frame pts is less
15497 than start_time + duration, 0 otherwise, and NaN if the start_time metadata is
15500 That basically means that an input frame is selected if its pts is within the
15501 interval set by the concat demuxer.
15505 The default value of the select expression is "1".
15507 @subsection Examples
15511 Select all frames in input:
15516 The example above is the same as:
15528 Select only I-frames:
15530 select='eq(pict_type\,I)'
15534 Select one frame every 100:
15536 select='not(mod(n\,100))'
15540 Select only frames contained in the 10-20 time interval:
15542 select=between(t\,10\,20)
15546 Select only I frames contained in the 10-20 time interval:
15548 select=between(t\,10\,20)*eq(pict_type\,I)
15552 Select frames with a minimum distance of 10 seconds:
15554 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
15558 Use aselect to select only audio frames with samples number > 100:
15560 aselect='gt(samples_n\,100)'
15564 Create a mosaic of the first scenes:
15566 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
15569 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
15573 Send even and odd frames to separate outputs, and compose them:
15575 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
15579 Select useful frames from an ffconcat file which is using inpoints and
15580 outpoints but where the source files are not intra frame only.
15582 ffmpeg -copyts -vsync 0 -segment_time_metadata 1 -i input.ffconcat -vf select=concatdec_select -af aselect=concatdec_select output.avi
15586 @section sendcmd, asendcmd
15588 Send commands to filters in the filtergraph.
15590 These filters read commands to be sent to other filters in the
15593 @code{sendcmd} must be inserted between two video filters,
15594 @code{asendcmd} must be inserted between two audio filters, but apart
15595 from that they act the same way.
15597 The specification of commands can be provided in the filter arguments
15598 with the @var{commands} option, or in a file specified by the
15599 @var{filename} option.
15601 These filters accept the following options:
15604 Set the commands to be read and sent to the other filters.
15606 Set the filename of the commands to be read and sent to the other
15610 @subsection Commands syntax
15612 A commands description consists of a sequence of interval
15613 specifications, comprising a list of commands to be executed when a
15614 particular event related to that interval occurs. The occurring event
15615 is typically the current frame time entering or leaving a given time
15618 An interval is specified by the following syntax:
15620 @var{START}[-@var{END}] @var{COMMANDS};
15623 The time interval is specified by the @var{START} and @var{END} times.
15624 @var{END} is optional and defaults to the maximum time.
15626 The current frame time is considered within the specified interval if
15627 it is included in the interval [@var{START}, @var{END}), that is when
15628 the time is greater or equal to @var{START} and is lesser than
15631 @var{COMMANDS} consists of a sequence of one or more command
15632 specifications, separated by ",", relating to that interval. The
15633 syntax of a command specification is given by:
15635 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
15638 @var{FLAGS} is optional and specifies the type of events relating to
15639 the time interval which enable sending the specified command, and must
15640 be a non-null sequence of identifier flags separated by "+" or "|" and
15641 enclosed between "[" and "]".
15643 The following flags are recognized:
15646 The command is sent when the current frame timestamp enters the
15647 specified interval. In other words, the command is sent when the
15648 previous frame timestamp was not in the given interval, and the
15652 The command is sent when the current frame timestamp leaves the
15653 specified interval. In other words, the command is sent when the
15654 previous frame timestamp was in the given interval, and the
15658 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
15661 @var{TARGET} specifies the target of the command, usually the name of
15662 the filter class or a specific filter instance name.
15664 @var{COMMAND} specifies the name of the command for the target filter.
15666 @var{ARG} is optional and specifies the optional list of argument for
15667 the given @var{COMMAND}.
15669 Between one interval specification and another, whitespaces, or
15670 sequences of characters starting with @code{#} until the end of line,
15671 are ignored and can be used to annotate comments.
15673 A simplified BNF description of the commands specification syntax
15676 @var{COMMAND_FLAG} ::= "enter" | "leave"
15677 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
15678 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
15679 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
15680 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
15681 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
15684 @subsection Examples
15688 Specify audio tempo change at second 4:
15690 asendcmd=c='4.0 atempo tempo 1.5',atempo
15694 Specify a list of drawtext and hue commands in a file.
15696 # show text in the interval 5-10
15697 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
15698 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
15700 # desaturate the image in the interval 15-20
15701 15.0-20.0 [enter] hue s 0,
15702 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
15704 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
15706 # apply an exponential saturation fade-out effect, starting from time 25
15707 25 [enter] hue s exp(25-t)
15710 A filtergraph allowing to read and process the above command list
15711 stored in a file @file{test.cmd}, can be specified with:
15713 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
15718 @section setpts, asetpts
15720 Change the PTS (presentation timestamp) of the input frames.
15722 @code{setpts} works on video frames, @code{asetpts} on audio frames.
15724 This filter accepts the following options:
15729 The expression which is evaluated for each frame to construct its timestamp.
15733 The expression is evaluated through the eval API and can contain the following
15738 frame rate, only defined for constant frame-rate video
15741 The presentation timestamp in input
15744 The count of the input frame for video or the number of consumed samples,
15745 not including the current frame for audio, starting from 0.
15747 @item NB_CONSUMED_SAMPLES
15748 The number of consumed samples, not including the current frame (only
15751 @item NB_SAMPLES, S
15752 The number of samples in the current frame (only audio)
15754 @item SAMPLE_RATE, SR
15755 The audio sample rate.
15758 The PTS of the first frame.
15761 the time in seconds of the first frame
15764 State whether the current frame is interlaced.
15767 the time in seconds of the current frame
15770 original position in the file of the frame, or undefined if undefined
15771 for the current frame
15774 The previous input PTS.
15777 previous input time in seconds
15780 The previous output PTS.
15783 previous output time in seconds
15786 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
15790 The wallclock (RTC) time at the start of the movie in microseconds.
15793 The timebase of the input timestamps.
15797 @subsection Examples
15801 Start counting PTS from zero
15803 setpts=PTS-STARTPTS
15807 Apply fast motion effect:
15813 Apply slow motion effect:
15819 Set fixed rate of 25 frames per second:
15825 Set fixed rate 25 fps with some jitter:
15827 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
15831 Apply an offset of 10 seconds to the input PTS:
15837 Generate timestamps from a "live source" and rebase onto the current timebase:
15839 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
15843 Generate timestamps by counting samples:
15850 @section settb, asettb
15852 Set the timebase to use for the output frames timestamps.
15853 It is mainly useful for testing timebase configuration.
15855 It accepts the following parameters:
15860 The expression which is evaluated into the output timebase.
15864 The value for @option{tb} is an arithmetic expression representing a
15865 rational. The expression can contain the constants "AVTB" (the default
15866 timebase), "intb" (the input timebase) and "sr" (the sample rate,
15867 audio only). Default value is "intb".
15869 @subsection Examples
15873 Set the timebase to 1/25:
15879 Set the timebase to 1/10:
15885 Set the timebase to 1001/1000:
15891 Set the timebase to 2*intb:
15897 Set the default timebase value:
15904 Convert input audio to a video output representing frequency spectrum
15905 logarithmically using Brown-Puckette constant Q transform algorithm with
15906 direct frequency domain coefficient calculation (but the transform itself
15907 is not really constant Q, instead the Q factor is actually variable/clamped),
15908 with musical tone scale, from E0 to D#10.
15910 The filter accepts the following options:
15914 Specify the video size for the output. It must be even. For the syntax of this option,
15915 check the @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15916 Default value is @code{1920x1080}.
15919 Set the output frame rate. Default value is @code{25}.
15922 Set the bargraph height. It must be even. Default value is @code{-1} which
15923 computes the bargraph height automatically.
15926 Set the axis height. It must be even. Default value is @code{-1} which computes
15927 the axis height automatically.
15930 Set the sonogram height. It must be even. Default value is @code{-1} which
15931 computes the sonogram height automatically.
15934 Set the fullhd resolution. This option is deprecated, use @var{size}, @var{s}
15935 instead. Default value is @code{1}.
15937 @item sono_v, volume
15938 Specify the sonogram volume expression. It can contain variables:
15941 the @var{bar_v} evaluated expression
15942 @item frequency, freq, f
15943 the frequency where it is evaluated
15944 @item timeclamp, tc
15945 the value of @var{timeclamp} option
15949 @item a_weighting(f)
15950 A-weighting of equal loudness
15951 @item b_weighting(f)
15952 B-weighting of equal loudness
15953 @item c_weighting(f)
15954 C-weighting of equal loudness.
15956 Default value is @code{16}.
15958 @item bar_v, volume2
15959 Specify the bargraph volume expression. It can contain variables:
15962 the @var{sono_v} evaluated expression
15963 @item frequency, freq, f
15964 the frequency where it is evaluated
15965 @item timeclamp, tc
15966 the value of @var{timeclamp} option
15970 @item a_weighting(f)
15971 A-weighting of equal loudness
15972 @item b_weighting(f)
15973 B-weighting of equal loudness
15974 @item c_weighting(f)
15975 C-weighting of equal loudness.
15977 Default value is @code{sono_v}.
15979 @item sono_g, gamma
15980 Specify the sonogram gamma. Lower gamma makes the spectrum more contrast,
15981 higher gamma makes the spectrum having more range. Default value is @code{3}.
15982 Acceptable range is @code{[1, 7]}.
15984 @item bar_g, gamma2
15985 Specify the bargraph gamma. Default value is @code{1}. Acceptable range is
15988 @item timeclamp, tc
15989 Specify the transform timeclamp. At low frequency, there is trade-off between
15990 accuracy in time domain and frequency domain. If timeclamp is lower,
15991 event in time domain is represented more accurately (such as fast bass drum),
15992 otherwise event in frequency domain is represented more accurately
15993 (such as bass guitar). Acceptable range is @code{[0.1, 1]}. Default value is @code{0.17}.
15996 Specify the transform base frequency. Default value is @code{20.01523126408007475},
15997 which is frequency 50 cents below E0. Acceptable range is @code{[10, 100000]}.
16000 Specify the transform end frequency. Default value is @code{20495.59681441799654},
16001 which is frequency 50 cents above D#10. Acceptable range is @code{[10, 100000]}.
16004 This option is deprecated and ignored.
16007 Specify the transform length in time domain. Use this option to control accuracy
16008 trade-off between time domain and frequency domain at every frequency sample.
16009 It can contain variables:
16011 @item frequency, freq, f
16012 the frequency where it is evaluated
16013 @item timeclamp, tc
16014 the value of @var{timeclamp} option.
16016 Default value is @code{384*tc/(384+tc*f)}.
16019 Specify the transform count for every video frame. Default value is @code{6}.
16020 Acceptable range is @code{[1, 30]}.
16023 Specify the transform count for every single pixel. Default value is @code{0},
16024 which makes it computed automatically. Acceptable range is @code{[0, 10]}.
16027 Specify font file for use with freetype to draw the axis. If not specified,
16028 use embedded font. Note that drawing with font file or embedded font is not
16029 implemented with custom @var{basefreq} and @var{endfreq}, use @var{axisfile}
16033 Specify font color expression. This is arithmetic expression that should return
16034 integer value 0xRRGGBB. It can contain variables:
16036 @item frequency, freq, f
16037 the frequency where it is evaluated
16038 @item timeclamp, tc
16039 the value of @var{timeclamp} option
16044 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
16045 @item r(x), g(x), b(x)
16046 red, green, and blue value of intensity x.
16048 Default value is @code{st(0, (midi(f)-59.5)/12);
16049 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
16050 r(1-ld(1)) + b(ld(1))}.
16053 Specify image file to draw the axis. This option override @var{fontfile} and
16054 @var{fontcolor} option.
16057 Enable/disable drawing text to the axis. If it is set to @code{0}, drawing to
16058 the axis is disabled, ignoring @var{fontfile} and @var{axisfile} option.
16059 Default value is @code{1}.
16063 @subsection Examples
16067 Playing audio while showing the spectrum:
16069 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
16073 Same as above, but with frame rate 30 fps:
16075 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
16079 Playing at 1280x720:
16081 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=s=1280x720:count=4 [out0]'
16085 Disable sonogram display:
16091 A1 and its harmonics: A1, A2, (near)E3, A3:
16093 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),
16094 asplit[a][out1]; [a] showcqt [out0]'
16098 Same as above, but with more accuracy in frequency domain:
16100 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),
16101 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
16107 bar_v=10:sono_v=bar_v*a_weighting(f)
16111 Custom gamma, now spectrum is linear to the amplitude.
16117 Custom tlength equation:
16119 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)))'
16123 Custom fontcolor and fontfile, C-note is colored green, others are colored blue:
16125 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))':fontfile=myfont.ttf
16129 Custom frequency range with custom axis using image file:
16131 axisfile=myaxis.png:basefreq=40:endfreq=10000
16137 Convert input audio to video output representing the audio power spectrum.
16138 Audio amplitude is on Y-axis while frequency is on X-axis.
16140 The filter accepts the following options:
16144 Specify size of video. For the syntax of this option, check the
16145 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16146 Default is @code{1024x512}.
16150 This set how each frequency bin will be represented.
16152 It accepts the following values:
16158 Default is @code{bar}.
16161 Set amplitude scale.
16163 It accepts the following values:
16177 Default is @code{log}.
16180 Set frequency scale.
16182 It accepts the following values:
16191 Reverse logarithmic scale.
16193 Default is @code{lin}.
16198 It accepts the following values:
16214 Default is @code{w2048}
16217 Set windowing function.
16219 It accepts the following values:
16237 Default is @code{hanning}.
16240 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
16241 which means optimal overlap for selected window function will be picked.
16244 Set time averaging. Setting this to 0 will display current maximal peaks.
16245 Default is @code{1}, which means time averaging is disabled.
16248 Specify list of colors separated by space or by '|' which will be used to
16249 draw channel frequencies. Unrecognized or missing colors will be replaced
16253 Set channel display mode.
16255 It accepts the following values:
16260 Default is @code{combined}.
16264 @anchor{showspectrum}
16265 @section showspectrum
16267 Convert input audio to a video output, representing the audio frequency
16270 The filter accepts the following options:
16274 Specify the video size for the output. For the syntax of this option, check the
16275 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16276 Default value is @code{640x512}.
16279 Specify how the spectrum should slide along the window.
16281 It accepts the following values:
16284 the samples start again on the left when they reach the right
16286 the samples scroll from right to left
16288 the samples scroll from left to right
16290 frames are only produced when the samples reach the right
16293 Default value is @code{replace}.
16296 Specify display mode.
16298 It accepts the following values:
16301 all channels are displayed in the same row
16303 all channels are displayed in separate rows
16306 Default value is @samp{combined}.
16309 Specify display color mode.
16311 It accepts the following values:
16314 each channel is displayed in a separate color
16316 each channel is displayed using the same color scheme
16318 each channel is displayed using the rainbow color scheme
16320 each channel is displayed using the moreland color scheme
16322 each channel is displayed using the nebulae color scheme
16324 each channel is displayed using the fire color scheme
16326 each channel is displayed using the fiery color scheme
16328 each channel is displayed using the fruit color scheme
16330 each channel is displayed using the cool color scheme
16333 Default value is @samp{channel}.
16336 Specify scale used for calculating intensity color values.
16338 It accepts the following values:
16343 square root, default
16354 Default value is @samp{sqrt}.
16357 Set saturation modifier for displayed colors. Negative values provide
16358 alternative color scheme. @code{0} is no saturation at all.
16359 Saturation must be in [-10.0, 10.0] range.
16360 Default value is @code{1}.
16363 Set window function.
16365 It accepts the following values:
16385 Default value is @code{hann}.
16388 Set orientation of time vs frequency axis. Can be @code{vertical} or
16389 @code{horizontal}. Default is @code{vertical}.
16392 Set ratio of overlap window. Default value is @code{0}.
16393 When value is @code{1} overlap is set to recommended size for specific
16394 window function currently used.
16397 Set scale gain for calculating intensity color values.
16398 Default value is @code{1}.
16401 Set which data to display. Can be @code{magnitude}, default or @code{phase}.
16404 The usage is very similar to the showwaves filter; see the examples in that
16407 @subsection Examples
16411 Large window with logarithmic color scaling:
16413 showspectrum=s=1280x480:scale=log
16417 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
16419 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
16420 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
16424 @section showspectrumpic
16426 Convert input audio to a single video frame, representing the audio frequency
16429 The filter accepts the following options:
16433 Specify the video size for the output. For the syntax of this option, check the
16434 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16435 Default value is @code{4096x2048}.
16438 Specify display mode.
16440 It accepts the following values:
16443 all channels are displayed in the same row
16445 all channels are displayed in separate rows
16447 Default value is @samp{combined}.
16450 Specify display color mode.
16452 It accepts the following values:
16455 each channel is displayed in a separate color
16457 each channel is displayed using the same color scheme
16459 each channel is displayed using the rainbow color scheme
16461 each channel is displayed using the moreland color scheme
16463 each channel is displayed using the nebulae color scheme
16465 each channel is displayed using the fire color scheme
16467 each channel is displayed using the fiery color scheme
16469 each channel is displayed using the fruit color scheme
16471 each channel is displayed using the cool color scheme
16473 Default value is @samp{intensity}.
16476 Specify scale used for calculating intensity color values.
16478 It accepts the following values:
16483 square root, default
16493 Default value is @samp{log}.
16496 Set saturation modifier for displayed colors. Negative values provide
16497 alternative color scheme. @code{0} is no saturation at all.
16498 Saturation must be in [-10.0, 10.0] range.
16499 Default value is @code{1}.
16502 Set window function.
16504 It accepts the following values:
16523 Default value is @code{hann}.
16526 Set orientation of time vs frequency axis. Can be @code{vertical} or
16527 @code{horizontal}. Default is @code{vertical}.
16530 Set scale gain for calculating intensity color values.
16531 Default value is @code{1}.
16534 Draw time and frequency axes and legends. Default is enabled.
16537 @subsection Examples
16541 Extract an audio spectrogram of a whole audio track
16542 in a 1024x1024 picture using @command{ffmpeg}:
16544 ffmpeg -i audio.flac -lavfi showspectrumpic=s=1024x1024 spectrogram.png
16548 @section showvolume
16550 Convert input audio volume to a video output.
16552 The filter accepts the following options:
16559 Set border width, allowed range is [0, 5]. Default is 1.
16562 Set channel width, allowed range is [80, 8192]. Default is 400.
16565 Set channel height, allowed range is [1, 900]. Default is 20.
16568 Set fade, allowed range is [0.001, 1]. Default is 0.95.
16571 Set volume color expression.
16573 The expression can use the following variables:
16577 Current max volume of channel in dB.
16580 Current channel number, starting from 0.
16584 If set, displays channel names. Default is enabled.
16587 If set, displays volume values. Default is enabled.
16590 Set orientation, can be @code{horizontal} or @code{vertical},
16591 default is @code{horizontal}.
16594 Set step size, allowed range s [0, 5]. Default is 0, which means
16600 Convert input audio to a video output, representing the samples waves.
16602 The filter accepts the following options:
16606 Specify the video size for the output. For the syntax of this option, check the
16607 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16608 Default value is @code{600x240}.
16613 Available values are:
16616 Draw a point for each sample.
16619 Draw a vertical line for each sample.
16622 Draw a point for each sample and a line between them.
16625 Draw a centered vertical line for each sample.
16628 Default value is @code{point}.
16631 Set the number of samples which are printed on the same column. A
16632 larger value will decrease the frame rate. Must be a positive
16633 integer. This option can be set only if the value for @var{rate}
16634 is not explicitly specified.
16637 Set the (approximate) output frame rate. This is done by setting the
16638 option @var{n}. Default value is "25".
16640 @item split_channels
16641 Set if channels should be drawn separately or overlap. Default value is 0.
16644 Set colors separated by '|' which are going to be used for drawing of each channel.
16647 Set amplitude scale. Can be linear @code{lin} or logarithmic @code{log}.
16652 @subsection Examples
16656 Output the input file audio and the corresponding video representation
16659 amovie=a.mp3,asplit[out0],showwaves[out1]
16663 Create a synthetic signal and show it with showwaves, forcing a
16664 frame rate of 30 frames per second:
16666 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
16670 @section showwavespic
16672 Convert input audio to a single video frame, representing the samples waves.
16674 The filter accepts the following options:
16678 Specify the video size for the output. For the syntax of this option, check the
16679 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16680 Default value is @code{600x240}.
16682 @item split_channels
16683 Set if channels should be drawn separately or overlap. Default value is 0.
16686 Set colors separated by '|' which are going to be used for drawing of each channel.
16689 Set amplitude scale. Can be linear @code{lin} or logarithmic @code{log}.
16693 @subsection Examples
16697 Extract a channel split representation of the wave form of a whole audio track
16698 in a 1024x800 picture using @command{ffmpeg}:
16700 ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png
16704 Colorize the waveform with colorchannelmixer. This example will make
16705 the waveform a green color approximately RGB(66,217,150). Additional
16706 channels will be shades of this color.
16708 ffmpeg -i audio.mp3 -filter_complex "showwavespic,colorchannelmixer=rr=66/255:gg=217/255:bb=150/255" waveform.png
16712 @section spectrumsynth
16714 Sythesize audio from 2 input video spectrums, first input stream represents
16715 magnitude across time and second represents phase across time.
16716 The filter will transform from frequency domain as displayed in videos back
16717 to time domain as presented in audio output.
16719 This filter is primarly created for reversing processed @ref{showspectrum}
16720 filter outputs, but can synthesize sound from other spectrograms too.
16721 But in such case results are going to be poor if the phase data is not
16722 available, because in such cases phase data need to be recreated, usually
16723 its just recreated from random noise.
16724 For best results use gray only output (@code{channel} color mode in
16725 @ref{showspectrum} filter) and @code{log} scale for magnitude video and
16726 @code{lin} scale for phase video. To produce phase, for 2nd video, use
16727 @code{data} option. Inputs videos should generally use @code{fullframe}
16728 slide mode as that saves resources needed for decoding video.
16730 The filter accepts the following options:
16734 Specify sample rate of output audio, the sample rate of audio from which
16735 spectrum was generated may differ.
16738 Set number of channels represented in input video spectrums.
16741 Set scale which was used when generating magnitude input spectrum.
16742 Can be @code{lin} or @code{log}. Default is @code{log}.
16745 Set slide which was used when generating inputs spectrums.
16746 Can be @code{replace}, @code{scroll}, @code{fullframe} or @code{rscroll}.
16747 Default is @code{fullframe}.
16750 Set window function used for resynthesis.
16753 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
16754 which means optimal overlap for selected window function will be picked.
16757 Set orientation of input videos. Can be @code{vertical} or @code{horizontal}.
16758 Default is @code{vertical}.
16761 @subsection Examples
16765 First create magnitude and phase videos from audio, assuming audio is stereo with 44100 sample rate,
16766 then resynthesize videos back to audio with spectrumsynth:
16768 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
16769 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
16770 ffmpeg -i magnitude.nut -i phase.nut -lavfi spectrumsynth=channels=2:sample_rate=44100:win_func=hann:overlap=0.875:slide=fullframe output.flac
16774 @section split, asplit
16776 Split input into several identical outputs.
16778 @code{asplit} works with audio input, @code{split} with video.
16780 The filter accepts a single parameter which specifies the number of outputs. If
16781 unspecified, it defaults to 2.
16783 @subsection Examples
16787 Create two separate outputs from the same input:
16789 [in] split [out0][out1]
16793 To create 3 or more outputs, you need to specify the number of
16796 [in] asplit=3 [out0][out1][out2]
16800 Create two separate outputs from the same input, one cropped and
16803 [in] split [splitout1][splitout2];
16804 [splitout1] crop=100:100:0:0 [cropout];
16805 [splitout2] pad=200:200:100:100 [padout];
16809 Create 5 copies of the input audio with @command{ffmpeg}:
16811 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
16817 Receive commands sent through a libzmq client, and forward them to
16818 filters in the filtergraph.
16820 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
16821 must be inserted between two video filters, @code{azmq} between two
16824 To enable these filters you need to install the libzmq library and
16825 headers and configure FFmpeg with @code{--enable-libzmq}.
16827 For more information about libzmq see:
16828 @url{http://www.zeromq.org/}
16830 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
16831 receives messages sent through a network interface defined by the
16832 @option{bind_address} option.
16834 The received message must be in the form:
16836 @var{TARGET} @var{COMMAND} [@var{ARG}]
16839 @var{TARGET} specifies the target of the command, usually the name of
16840 the filter class or a specific filter instance name.
16842 @var{COMMAND} specifies the name of the command for the target filter.
16844 @var{ARG} is optional and specifies the optional argument list for the
16845 given @var{COMMAND}.
16847 Upon reception, the message is processed and the corresponding command
16848 is injected into the filtergraph. Depending on the result, the filter
16849 will send a reply to the client, adopting the format:
16851 @var{ERROR_CODE} @var{ERROR_REASON}
16855 @var{MESSAGE} is optional.
16857 @subsection Examples
16859 Look at @file{tools/zmqsend} for an example of a zmq client which can
16860 be used to send commands processed by these filters.
16862 Consider the following filtergraph generated by @command{ffplay}
16864 ffplay -dumpgraph 1 -f lavfi "
16865 color=s=100x100:c=red [l];
16866 color=s=100x100:c=blue [r];
16867 nullsrc=s=200x100, zmq [bg];
16868 [bg][l] overlay [bg+l];
16869 [bg+l][r] overlay=x=100 "
16872 To change the color of the left side of the video, the following
16873 command can be used:
16875 echo Parsed_color_0 c yellow | tools/zmqsend
16878 To change the right side:
16880 echo Parsed_color_1 c pink | tools/zmqsend
16883 @c man end MULTIMEDIA FILTERS
16885 @chapter Multimedia Sources
16886 @c man begin MULTIMEDIA SOURCES
16888 Below is a description of the currently available multimedia sources.
16892 This is the same as @ref{movie} source, except it selects an audio
16898 Read audio and/or video stream(s) from a movie container.
16900 It accepts the following parameters:
16904 The name of the resource to read (not necessarily a file; it can also be a
16905 device or a stream accessed through some protocol).
16907 @item format_name, f
16908 Specifies the format assumed for the movie to read, and can be either
16909 the name of a container or an input device. If not specified, the
16910 format is guessed from @var{movie_name} or by probing.
16912 @item seek_point, sp
16913 Specifies the seek point in seconds. The frames will be output
16914 starting from this seek point. The parameter is evaluated with
16915 @code{av_strtod}, so the numerical value may be suffixed by an IS
16916 postfix. The default value is "0".
16919 Specifies the streams to read. Several streams can be specified,
16920 separated by "+". The source will then have as many outputs, in the
16921 same order. The syntax is explained in the ``Stream specifiers''
16922 section in the ffmpeg manual. Two special names, "dv" and "da" specify
16923 respectively the default (best suited) video and audio stream. Default
16924 is "dv", or "da" if the filter is called as "amovie".
16926 @item stream_index, si
16927 Specifies the index of the video stream to read. If the value is -1,
16928 the most suitable video stream will be automatically selected. The default
16929 value is "-1". Deprecated. If the filter is called "amovie", it will select
16930 audio instead of video.
16933 Specifies how many times to read the stream in sequence.
16934 If the value is less than 1, the stream will be read again and again.
16935 Default value is "1".
16937 Note that when the movie is looped the source timestamps are not
16938 changed, so it will generate non monotonically increasing timestamps.
16941 It allows overlaying a second video on top of the main input of
16942 a filtergraph, as shown in this graph:
16944 input -----------> deltapts0 --> overlay --> output
16947 movie --> scale--> deltapts1 -------+
16949 @subsection Examples
16953 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
16954 on top of the input labelled "in":
16956 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
16957 [in] setpts=PTS-STARTPTS [main];
16958 [main][over] overlay=16:16 [out]
16962 Read from a video4linux2 device, and overlay it on top of the input
16965 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
16966 [in] setpts=PTS-STARTPTS [main];
16967 [main][over] overlay=16:16 [out]
16971 Read the first video stream and the audio stream with id 0x81 from
16972 dvd.vob; the video is connected to the pad named "video" and the audio is
16973 connected to the pad named "audio":
16975 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
16979 @c man end MULTIMEDIA SOURCES