1 @chapter Filtering Introduction
2 @c man begin FILTERING INTRODUCTION
4 Filtering in FFmpeg is enabled through the libavfilter library.
6 In libavfilter, a filter can have multiple inputs and multiple
8 To illustrate the sorts of things that are possible, we consider the
13 input --> split ---------------------> overlay --> output
16 +-----> crop --> vflip -------+
19 This filtergraph splits the input stream in two streams, then sends one
20 stream through the crop filter and the vflip filter, before merging it
21 back with the other stream by overlaying it on top. You can use the
22 following command to achieve this:
25 ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
28 The result will be that the top half of the video is mirrored
29 onto the bottom half of the output video.
31 Filters in the same linear chain are separated by commas, and distinct
32 linear chains of filters are separated by semicolons. In our example,
33 @var{crop,vflip} are in one linear chain, @var{split} and
34 @var{overlay} are separately in another. The points where the linear
35 chains join are labelled by names enclosed in square brackets. In the
36 example, the split filter generates two outputs that are associated to
37 the labels @var{[main]} and @var{[tmp]}.
39 The stream sent to the second output of @var{split}, labelled as
40 @var{[tmp]}, is processed through the @var{crop} filter, which crops
41 away the lower half part of the video, and then vertically flipped. The
42 @var{overlay} filter takes in input the first unchanged output of the
43 split filter (which was labelled as @var{[main]}), and overlay on its
44 lower half the output generated by the @var{crop,vflip} filterchain.
46 Some filters take in input a list of parameters: they are specified
47 after the filter name and an equal sign, and are separated from each other
50 There exist so-called @var{source filters} that do not have an
51 audio/video input, and @var{sink filters} that will not have audio/video
54 @c man end FILTERING INTRODUCTION
57 @c man begin GRAPH2DOT
59 The @file{graph2dot} program included in the FFmpeg @file{tools}
60 directory can be used to parse a filtergraph description and issue a
61 corresponding textual representation in the dot language.
68 to see how to use @file{graph2dot}.
70 You can then pass the dot description to the @file{dot} program (from
71 the graphviz suite of programs) and obtain a graphical representation
74 For example the sequence of commands:
76 echo @var{GRAPH_DESCRIPTION} | \
77 tools/graph2dot -o graph.tmp && \
78 dot -Tpng graph.tmp -o graph.png && \
82 can be used to create and display an image representing the graph
83 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
84 a complete self-contained graph, with its inputs and outputs explicitly defined.
85 For example if your command line is of the form:
87 ffmpeg -i infile -vf scale=640:360 outfile
89 your @var{GRAPH_DESCRIPTION} string will need to be of the form:
91 nullsrc,scale=640:360,nullsink
93 you may also need to set the @var{nullsrc} parameters and add a @var{format}
94 filter in order to simulate a specific input file.
98 @chapter Filtergraph description
99 @c man begin FILTERGRAPH DESCRIPTION
101 A filtergraph is a directed graph of connected filters. It can contain
102 cycles, and there can be multiple links between a pair of
103 filters. Each link has one input pad on one side connecting it to one
104 filter from which it takes its input, and one output pad on the other
105 side connecting it to one filter accepting its output.
107 Each filter in a filtergraph is an instance of a filter class
108 registered in the application, which defines the features and the
109 number of input and output pads of the filter.
111 A filter with no input pads is called a "source", and a filter with no
112 output pads is called a "sink".
114 @anchor{Filtergraph syntax}
115 @section Filtergraph syntax
117 A filtergraph has a textual representation, which is recognized by the
118 @option{-filter}/@option{-vf}/@option{-af} and
119 @option{-filter_complex} options in @command{ffmpeg} and
120 @option{-vf}/@option{-af} in @command{ffplay}, and by the
121 @code{avfilter_graph_parse_ptr()} function defined in
122 @file{libavfilter/avfilter.h}.
124 A filterchain consists of a sequence of connected filters, each one
125 connected to the previous one in the sequence. A filterchain is
126 represented by a list of ","-separated filter descriptions.
128 A filtergraph consists of a sequence of filterchains. A sequence of
129 filterchains is represented by a list of ";"-separated filterchain
132 A filter is represented by a string of the form:
133 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
135 @var{filter_name} is the name of the filter class of which the
136 described filter is an instance of, and has to be the name of one of
137 the filter classes registered in the program.
138 The name of the filter class is optionally followed by a string
141 @var{arguments} is a string which contains the parameters used to
142 initialize the filter instance. It may have one of two forms:
146 A ':'-separated list of @var{key=value} pairs.
149 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
150 the option names in the order they are declared. E.g. the @code{fade} filter
151 declares three options in this order -- @option{type}, @option{start_frame} and
152 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
153 @var{in} is assigned to the option @option{type}, @var{0} to
154 @option{start_frame} and @var{30} to @option{nb_frames}.
157 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
158 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
159 follow the same constraints order of the previous point. The following
160 @var{key=value} pairs can be set in any preferred order.
164 If the option value itself is a list of items (e.g. the @code{format} filter
165 takes a list of pixel formats), the items in the list are usually separated by
168 The list of arguments can be quoted using the character @samp{'} as initial
169 and ending mark, and the character @samp{\} for escaping the characters
170 within the quoted text; otherwise the argument string is considered
171 terminated when the next special character (belonging to the set
172 @samp{[]=;,}) is encountered.
174 The name and arguments of the filter are optionally preceded and
175 followed by a list of link labels.
176 A link label allows one to name a link and associate it to a filter output
177 or input pad. The preceding labels @var{in_link_1}
178 ... @var{in_link_N}, are associated to the filter input pads,
179 the following labels @var{out_link_1} ... @var{out_link_M}, are
180 associated to the output pads.
182 When two link labels with the same name are found in the
183 filtergraph, a link between the corresponding input and output pad is
186 If an output pad is not labelled, it is linked by default to the first
187 unlabelled input pad of the next filter in the filterchain.
188 For example in the filterchain
190 nullsrc, split[L1], [L2]overlay, nullsink
192 the split filter instance has two output pads, and the overlay filter
193 instance two input pads. The first output pad of split is labelled
194 "L1", the first input pad of overlay is labelled "L2", and the second
195 output pad of split is linked to the second input pad of overlay,
196 which are both unlabelled.
198 In a filter description, if the input label of the first filter is not
199 specified, "in" is assumed; if the output label of the last filter is not
200 specified, "out" is assumed.
202 In a complete filterchain all the unlabelled filter input and output
203 pads must be connected. A filtergraph is considered valid if all the
204 filter input and output pads of all the filterchains are connected.
206 Libavfilter will automatically insert @ref{scale} filters where format
207 conversion is required. It is possible to specify swscale flags
208 for those automatically inserted scalers by prepending
209 @code{sws_flags=@var{flags};}
210 to the filtergraph description.
212 Here is a BNF description of the filtergraph syntax:
214 @var{NAME} ::= sequence of alphanumeric characters and '_'
215 @var{LINKLABEL} ::= "[" @var{NAME} "]"
216 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
217 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
218 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
219 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
220 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
223 @section Notes on filtergraph escaping
225 Filtergraph description composition entails several levels of
226 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
227 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
228 information about the employed escaping procedure.
230 A first level escaping affects the content of each filter option
231 value, which may contain the special character @code{:} used to
232 separate values, or one of the escaping characters @code{\'}.
234 A second level escaping affects the whole filter description, which
235 may contain the escaping characters @code{\'} or the special
236 characters @code{[],;} used by the filtergraph description.
238 Finally, when you specify a filtergraph on a shell commandline, you
239 need to perform a third level escaping for the shell special
240 characters contained within it.
242 For example, consider the following string to be embedded in
243 the @ref{drawtext} filter description @option{text} value:
245 this is a 'string': may contain one, or more, special characters
248 This string contains the @code{'} special escaping character, and the
249 @code{:} special character, so it needs to be escaped in this way:
251 text=this is a \'string\'\: may contain one, or more, special characters
254 A second level of escaping is required when embedding the filter
255 description in a filtergraph description, in order to escape all the
256 filtergraph special characters. Thus the example above becomes:
258 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
260 (note that in addition to the @code{\'} escaping special characters,
261 also @code{,} needs to be escaped).
263 Finally an additional level of escaping is needed when writing the
264 filtergraph description in a shell command, which depends on the
265 escaping rules of the adopted shell. For example, assuming that
266 @code{\} is special and needs to be escaped with another @code{\}, the
267 previous string will finally result in:
269 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
272 @chapter Timeline editing
274 Some filters support a generic @option{enable} option. For the filters
275 supporting timeline editing, this option can be set to an expression which is
276 evaluated before sending a frame to the filter. If the evaluation is non-zero,
277 the filter will be enabled, otherwise the frame will be sent unchanged to the
278 next filter in the filtergraph.
280 The expression accepts the following values:
283 timestamp expressed in seconds, NAN if the input timestamp is unknown
286 sequential number of the input frame, starting from 0
289 the position in the file of the input frame, NAN if unknown
293 width and height of the input frame if video
296 Additionally, these filters support an @option{enable} command that can be used
297 to re-define the expression.
299 Like any other filtering option, the @option{enable} option follows the same
302 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
303 minutes, and a @ref{curves} filter starting at 3 seconds:
305 smartblur = enable='between(t,10,3*60)',
306 curves = enable='gte(t,3)' : preset=cross_process
309 @c man end FILTERGRAPH DESCRIPTION
311 @chapter Audio Filters
312 @c man begin AUDIO FILTERS
314 When you configure your FFmpeg build, you can disable any of the
315 existing filters using @code{--disable-filters}.
316 The configure output will show the audio filters included in your
319 Below is a description of the currently available audio filters.
323 A compressor is mainly used to reduce the dynamic range of a signal.
324 Especially modern music is mostly compressed at a high ratio to
325 improve the overall loudness. It's done to get the highest attention
326 of a listener, "fatten" the sound and bring more "power" to the track.
327 If a signal is compressed too much it may sound dull or "dead"
328 afterwards or it may start to "pump" (which could be a powerful effect
329 but can also destroy a track completely).
330 The right compression is the key to reach a professional sound and is
331 the high art of mixing and mastering. Because of its complex settings
332 it may take a long time to get the right feeling for this kind of effect.
334 Compression is done by detecting the volume above a chosen level
335 @code{threshold} and dividing it by the factor set with @code{ratio}.
336 So if you set the threshold to -12dB and your signal reaches -6dB a ratio
337 of 2:1 will result in a signal at -9dB. Because an exact manipulation of
338 the signal would cause distortion of the waveform the reduction can be
339 levelled over the time. This is done by setting "Attack" and "Release".
340 @code{attack} determines how long the signal has to rise above the threshold
341 before any reduction will occur and @code{release} sets the time the signal
342 has to fall below the threshold to reduce the reduction again. Shorter signals
343 than the chosen attack time will be left untouched.
344 The overall reduction of the signal can be made up afterwards with the
345 @code{makeup} setting. So compressing the peaks of a signal about 6dB and
346 raising the makeup to this level results in a signal twice as loud than the
347 source. To gain a softer entry in the compression the @code{knee} flattens the
348 hard edge at the threshold in the range of the chosen decibels.
350 The filter accepts the following options:
354 Set input gain. Default is 1. Range is between 0.015625 and 64.
357 If a signal of second stream rises above this level it will affect the gain
358 reduction of the first stream.
359 By default it is 0.125. Range is between 0.00097563 and 1.
362 Set a ratio by which the signal is reduced. 1:2 means that if the level
363 rose 4dB above the threshold, it will be only 2dB above after the reduction.
364 Default is 2. Range is between 1 and 20.
367 Amount of milliseconds the signal has to rise above the threshold before gain
368 reduction starts. Default is 20. Range is between 0.01 and 2000.
371 Amount of milliseconds the signal has to fall below the threshold before
372 reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
375 Set the amount by how much signal will be amplified after processing.
376 Default is 2. Range is from 1 and 64.
379 Curve the sharp knee around the threshold to enter gain reduction more softly.
380 Default is 2.82843. Range is between 1 and 8.
383 Choose if the @code{average} level between all channels of input stream
384 or the louder(@code{maximum}) channel of input stream affects the
385 reduction. Default is @code{average}.
388 Should the exact signal be taken in case of @code{peak} or an RMS one in case
389 of @code{rms}. Default is @code{rms} which is mostly smoother.
392 How much to use compressed signal in output. Default is 1.
393 Range is between 0 and 1.
398 Apply cross fade from one input audio stream to another input audio stream.
399 The cross fade is applied for specified duration near the end of first stream.
401 The filter accepts the following options:
405 Specify the number of samples for which the cross fade effect has to last.
406 At the end of the cross fade effect the first input audio will be completely
407 silent. Default is 44100.
410 Specify the duration of the cross fade effect. See
411 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
412 for the accepted syntax.
413 By default the duration is determined by @var{nb_samples}.
414 If set this option is used instead of @var{nb_samples}.
417 Should first stream end overlap with second stream start. Default is enabled.
420 Set curve for cross fade transition for first stream.
423 Set curve for cross fade transition for second stream.
425 For description of available curve types see @ref{afade} filter description.
432 Cross fade from one input to another:
434 ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:c1=exp:c2=exp output.flac
438 Cross fade from one input to another but without overlapping:
440 ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:o=0:c1=exp:c2=exp output.flac
446 Delay one or more audio channels.
448 Samples in delayed channel are filled with silence.
450 The filter accepts the following option:
454 Set list of delays in milliseconds for each channel separated by '|'.
455 At least one delay greater than 0 should be provided.
456 Unused delays will be silently ignored. If number of given delays is
457 smaller than number of channels all remaining channels will not be delayed.
464 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
465 the second channel (and any other channels that may be present) unchanged.
473 Apply echoing to the input audio.
475 Echoes are reflected sound and can occur naturally amongst mountains
476 (and sometimes large buildings) when talking or shouting; digital echo
477 effects emulate this behaviour and are often used to help fill out the
478 sound of a single instrument or vocal. The time difference between the
479 original signal and the reflection is the @code{delay}, and the
480 loudness of the reflected signal is the @code{decay}.
481 Multiple echoes can have different delays and decays.
483 A description of the accepted parameters follows.
487 Set input gain of reflected signal. Default is @code{0.6}.
490 Set output gain of reflected signal. Default is @code{0.3}.
493 Set list of time intervals in milliseconds between original signal and reflections
494 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
495 Default is @code{1000}.
498 Set list of loudnesses of reflected signals separated by '|'.
499 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
500 Default is @code{0.5}.
507 Make it sound as if there are twice as many instruments as are actually playing:
509 aecho=0.8:0.88:60:0.4
513 If delay is very short, then it sound like a (metallic) robot playing music:
519 A longer delay will sound like an open air concert in the mountains:
521 aecho=0.8:0.9:1000:0.3
525 Same as above but with one more mountain:
527 aecho=0.8:0.9:1000|1800:0.3|0.25
532 Audio emphasis filter creates or restores material directly taken from LPs or
533 emphased CDs with different filter curves. E.g. to store music on vinyl the
534 signal has to be altered by a filter first to even out the disadvantages of
535 this recording medium.
536 Once the material is played back the inverse filter has to be applied to
537 restore the distortion of the frequency response.
539 The filter accepts the following options:
549 Set filter mode. For restoring material use @code{reproduction} mode, otherwise
550 use @code{production} mode. Default is @code{reproduction} mode.
553 Set filter type. Selects medium. Can be one of the following:
565 select Compact Disc (CD).
571 select 50µs (FM-KF).
573 select 75µs (FM-KF).
579 Modify an audio signal according to the specified expressions.
581 This filter accepts one or more expressions (one for each channel),
582 which are evaluated and used to modify a corresponding audio signal.
584 It accepts the following parameters:
588 Set the '|'-separated expressions list for each separate channel. If
589 the number of input channels is greater than the number of
590 expressions, the last specified expression is used for the remaining
593 @item channel_layout, c
594 Set output channel layout. If not specified, the channel layout is
595 specified by the number of expressions. If set to @samp{same}, it will
596 use by default the same input channel layout.
599 Each expression in @var{exprs} can contain the following constants and functions:
603 channel number of the current expression
606 number of the evaluated sample, starting from 0
612 time of the evaluated sample expressed in seconds
615 @item nb_out_channels
616 input and output number of channels
619 the value of input channel with number @var{CH}
622 Note: this filter is slow. For faster processing you should use a
631 aeval=val(ch)/2:c=same
635 Invert phase of the second channel:
644 Apply fade-in/out effect to input audio.
646 A description of the accepted parameters follows.
650 Specify the effect type, can be either @code{in} for fade-in, or
651 @code{out} for a fade-out effect. Default is @code{in}.
653 @item start_sample, ss
654 Specify the number of the start sample for starting to apply the fade
655 effect. Default is 0.
658 Specify the number of samples for which the fade effect has to last. At
659 the end of the fade-in effect the output audio will have the same
660 volume as the input audio, at the end of the fade-out transition
661 the output audio will be silence. Default is 44100.
664 Specify the start time of the fade effect. Default is 0.
665 The value must be specified as a time duration; see
666 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
667 for the accepted syntax.
668 If set this option is used instead of @var{start_sample}.
671 Specify the duration of the fade effect. See
672 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
673 for the accepted syntax.
674 At the end of the fade-in effect the output audio will have the same
675 volume as the input audio, at the end of the fade-out transition
676 the output audio will be silence.
677 By default the duration is determined by @var{nb_samples}.
678 If set this option is used instead of @var{nb_samples}.
681 Set curve for fade transition.
683 It accepts the following values:
686 select triangular, linear slope (default)
688 select quarter of sine wave
690 select half of sine wave
692 select exponential sine wave
696 select inverted parabola
710 select inverted quarter of sine wave
712 select inverted half of sine wave
714 select double-exponential seat
716 select double-exponential sigmoid
724 Fade in first 15 seconds of audio:
730 Fade out last 25 seconds of a 900 seconds audio:
732 afade=t=out:st=875:d=25
737 Apply arbitrary expressions to samples in frequency domain.
741 Set frequency domain real expression for each separate channel separated
742 by '|'. Default is "1".
743 If the number of input channels is greater than the number of
744 expressions, the last specified expression is used for the remaining
748 Set frequency domain imaginary expression for each separate channel
749 separated by '|'. If not set, @var{real} option is used.
751 Each expression in @var{real} and @var{imag} can contain the following
759 current frequency bin number
762 number of available bins
765 channel number of the current expression
777 It accepts the following values:
793 Default is @code{w4096}
796 Set window function. Default is @code{hann}.
799 Set window overlap. If set to 1, the recommended overlap for selected
800 window function will be picked. Default is @code{0.75}.
807 Leave almost only low frequencies in audio:
809 afftfilt="1-clip((b/nb)*b,0,1)"
816 Set output format constraints for the input audio. The framework will
817 negotiate the most appropriate format to minimize conversions.
819 It accepts the following parameters:
823 A '|'-separated list of requested sample formats.
826 A '|'-separated list of requested sample rates.
828 @item channel_layouts
829 A '|'-separated list of requested channel layouts.
831 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
832 for the required syntax.
835 If a parameter is omitted, all values are allowed.
837 Force the output to either unsigned 8-bit or signed 16-bit stereo
839 aformat=sample_fmts=u8|s16:channel_layouts=stereo
844 A gate is mainly used to reduce lower parts of a signal. This kind of signal
845 processing reduces disturbing noise between useful signals.
847 Gating is done by detecting the volume below a chosen level @var{threshold}
848 and divide it by the factor set with @var{ratio}. The bottom of the noise
849 floor is set via @var{range}. Because an exact manipulation of the signal
850 would cause distortion of the waveform the reduction can be levelled over
851 time. This is done by setting @var{attack} and @var{release}.
853 @var{attack} determines how long the signal has to fall below the threshold
854 before any reduction will occur and @var{release} sets the time the signal
855 has to raise above the threshold to reduce the reduction again.
856 Shorter signals than the chosen attack time will be left untouched.
860 Set input level before filtering.
861 Default is 1. Allowed range is from 0.015625 to 64.
864 Set the level of gain reduction when the signal is below the threshold.
865 Default is 0.06125. Allowed range is from 0 to 1.
868 If a signal rises above this level the gain reduction is released.
869 Default is 0.125. Allowed range is from 0 to 1.
872 Set a ratio about which the signal is reduced.
873 Default is 2. Allowed range is from 1 to 9000.
876 Amount of milliseconds the signal has to rise above the threshold before gain
878 Default is 20 milliseconds. Allowed range is from 0.01 to 9000.
881 Amount of milliseconds the signal has to fall below the threshold before the
882 reduction is increased again. Default is 250 milliseconds.
883 Allowed range is from 0.01 to 9000.
886 Set amount of amplification of signal after processing.
887 Default is 1. Allowed range is from 1 to 64.
890 Curve the sharp knee around the threshold to enter gain reduction more softly.
891 Default is 2.828427125. Allowed range is from 1 to 8.
894 Choose if exact signal should be taken for detection or an RMS like one.
895 Default is rms. Can be peak or rms.
898 Choose if the average level between all channels or the louder channel affects
900 Default is average. Can be average or maximum.
905 The limiter prevents input signal from raising over a desired threshold.
906 This limiter uses lookahead technology to prevent your signal from distorting.
907 It means that there is a small delay after signal is processed. Keep in mind
908 that the delay it produces is the attack time you set.
910 The filter accepts the following options:
914 Set input gain. Default is 1.
917 Set output gain. Default is 1.
920 Don't let signals above this level pass the limiter. Default is 1.
923 The limiter will reach its attenuation level in this amount of time in
924 milliseconds. Default is 5 milliseconds.
927 Come back from limiting to attenuation 1.0 in this amount of milliseconds.
928 Default is 50 milliseconds.
931 When gain reduction is always needed ASC takes care of releasing to an
932 average reduction level rather than reaching a reduction of 0 in the release
936 Select how much the release time is affected by ASC, 0 means nearly no changes
937 in release time while 1 produces higher release times.
940 Auto level output signal. Default is enabled.
941 This normalizes audio back to 0dB if enabled.
944 Depending on picked setting it is recommended to upsample input 2x or 4x times
945 with @ref{aresample} before applying this filter.
949 Apply a two-pole all-pass filter with central frequency (in Hz)
950 @var{frequency}, and filter-width @var{width}.
951 An all-pass filter changes the audio's frequency to phase relationship
952 without changing its frequency to amplitude relationship.
954 The filter accepts the following options:
961 Set method to specify band-width of filter.
974 Specify the band-width of a filter in width_type units.
980 Merge two or more audio streams into a single multi-channel stream.
982 The filter accepts the following options:
987 Set the number of inputs. Default is 2.
991 If the channel layouts of the inputs are disjoint, and therefore compatible,
992 the channel layout of the output will be set accordingly and the channels
993 will be reordered as necessary. If the channel layouts of the inputs are not
994 disjoint, the output will have all the channels of the first input then all
995 the channels of the second input, in that order, and the channel layout of
996 the output will be the default value corresponding to the total number of
999 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
1000 is FC+BL+BR, then the output will be in 5.1, with the channels in the
1001 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
1002 first input, b1 is the first channel of the second input).
1004 On the other hand, if both input are in stereo, the output channels will be
1005 in the default order: a1, a2, b1, b2, and the channel layout will be
1006 arbitrarily set to 4.0, which may or may not be the expected value.
1008 All inputs must have the same sample rate, and format.
1010 If inputs do not have the same duration, the output will stop with the
1013 @subsection Examples
1017 Merge two mono files into a stereo stream:
1019 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
1023 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
1025 ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv
1031 Mixes multiple audio inputs into a single output.
1033 Note that this filter only supports float samples (the @var{amerge}
1034 and @var{pan} audio filters support many formats). If the @var{amix}
1035 input has integer samples then @ref{aresample} will be automatically
1036 inserted to perform the conversion to float samples.
1040 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
1042 will mix 3 input audio streams to a single output with the same duration as the
1043 first input and a dropout transition time of 3 seconds.
1045 It accepts the following parameters:
1049 The number of inputs. If unspecified, it defaults to 2.
1052 How to determine the end-of-stream.
1056 The duration of the longest input. (default)
1059 The duration of the shortest input.
1062 The duration of the first input.
1066 @item dropout_transition
1067 The transition time, in seconds, for volume renormalization when an input
1068 stream ends. The default value is 2 seconds.
1072 @section anequalizer
1074 High-order parametric multiband equalizer for each channel.
1076 It accepts the following parameters:
1080 This option string is in format:
1081 "c@var{chn} f=@var{cf} w=@var{w} g=@var{g} t=@var{f} | ..."
1082 Each equalizer band is separated by '|'.
1086 Set channel number to which equalization will be applied.
1087 If input doesn't have that channel the entry is ignored.
1090 Set central frequency for band.
1091 If input doesn't have that frequency the entry is ignored.
1094 Set band width in hertz.
1097 Set band gain in dB.
1100 Set filter type for band, optional, can be:
1104 Butterworth, this is default.
1115 With this option activated frequency response of anequalizer is displayed
1119 Set video stream size. Only useful if curves option is activated.
1122 Set max gain that will be displayed. Only useful if curves option is activated.
1123 Setting this to reasonable value allows to display gain which is derived from
1124 neighbour bands which are too close to each other and thus produce higher gain
1125 when both are activated.
1128 Set frequency scale used to draw frequency response in video output.
1129 Can be linear or logarithmic. Default is logarithmic.
1132 Set color for each channel curve which is going to be displayed in video stream.
1133 This is list of color names separated by space or by '|'.
1134 Unrecognised or missing colors will be replaced by white color.
1137 @subsection Examples
1141 Lower gain by 10 of central frequency 200Hz and width 100 Hz
1142 for first 2 channels using Chebyshev type 1 filter:
1144 anequalizer=c0 f=200 w=100 g=-10 t=1|c1 f=200 w=100 g=-10 t=1
1148 @subsection Commands
1150 This filter supports the following commands:
1153 Alter existing filter parameters.
1154 Syntax for the commands is : "@var{fN}|f=@var{freq}|w=@var{width}|g=@var{gain}"
1156 @var{fN} is existing filter number, starting from 0, if no such filter is available
1158 @var{freq} set new frequency parameter.
1159 @var{width} set new width parameter in herz.
1160 @var{gain} set new gain parameter in dB.
1162 Full filter invocation with asendcmd may look like this:
1163 asendcmd=c='4.0 anequalizer change 0|f=200|w=50|g=1',anequalizer=...
1168 Pass the audio source unchanged to the output.
1172 Pad the end of an audio stream with silence.
1174 This can be used together with @command{ffmpeg} @option{-shortest} to
1175 extend audio streams to the same length as the video stream.
1177 A description of the accepted options follows.
1181 Set silence packet size. Default value is 4096.
1184 Set the number of samples of silence to add to the end. After the
1185 value is reached, the stream is terminated. This option is mutually
1186 exclusive with @option{whole_len}.
1189 Set the minimum total number of samples in the output audio stream. If
1190 the value is longer than the input audio length, silence is added to
1191 the end, until the value is reached. This option is mutually exclusive
1192 with @option{pad_len}.
1195 If neither the @option{pad_len} nor the @option{whole_len} option is
1196 set, the filter will add silence to the end of the input stream
1199 @subsection Examples
1203 Add 1024 samples of silence to the end of the input:
1209 Make sure the audio output will contain at least 10000 samples, pad
1210 the input with silence if required:
1212 apad=whole_len=10000
1216 Use @command{ffmpeg} to pad the audio input with silence, so that the
1217 video stream will always result the shortest and will be converted
1218 until the end in the output file when using the @option{shortest}
1221 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
1226 Add a phasing effect to the input audio.
1228 A phaser filter creates series of peaks and troughs in the frequency spectrum.
1229 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
1231 A description of the accepted parameters follows.
1235 Set input gain. Default is 0.4.
1238 Set output gain. Default is 0.74
1241 Set delay in milliseconds. Default is 3.0.
1244 Set decay. Default is 0.4.
1247 Set modulation speed in Hz. Default is 0.5.
1250 Set modulation type. Default is triangular.
1252 It accepts the following values:
1261 Audio pulsator is something between an autopanner and a tremolo.
1262 But it can produce funny stereo effects as well. Pulsator changes the volume
1263 of the left and right channel based on a LFO (low frequency oscillator) with
1264 different waveforms and shifted phases.
1265 This filter have the ability to define an offset between left and right
1266 channel. An offset of 0 means that both LFO shapes match each other.
1267 The left and right channel are altered equally - a conventional tremolo.
1268 An offset of 50% means that the shape of the right channel is exactly shifted
1269 in phase (or moved backwards about half of the frequency) - pulsator acts as
1270 an autopanner. At 1 both curves match again. Every setting in between moves the
1271 phase shift gapless between all stages and produces some "bypassing" sounds with
1272 sine and triangle waveforms. The more you set the offset near 1 (starting from
1273 the 0.5) the faster the signal passes from the left to the right speaker.
1275 The filter accepts the following options:
1279 Set input gain. By default it is 1. Range is [0.015625 - 64].
1282 Set output gain. By default it is 1. Range is [0.015625 - 64].
1285 Set waveform shape the LFO will use. Can be one of: sine, triangle, square,
1286 sawup or sawdown. Default is sine.
1289 Set modulation. Define how much of original signal is affected by the LFO.
1292 Set left channel offset. Default is 0. Allowed range is [0 - 1].
1295 Set right channel offset. Default is 0.5. Allowed range is [0 - 1].
1298 Set pulse width. Default is 1. Allowed range is [0 - 2].
1301 Set possible timing mode. Can be one of: bpm, ms or hz. Default is hz.
1304 Set bpm. Default is 120. Allowed range is [30 - 300]. Only used if timing
1308 Set ms. Default is 500. Allowed range is [10 - 2000]. Only used if timing
1312 Set frequency in Hz. Default is 2. Allowed range is [0.01 - 100]. Only used
1313 if timing is set to hz.
1319 Resample the input audio to the specified parameters, using the
1320 libswresample library. If none are specified then the filter will
1321 automatically convert between its input and output.
1323 This filter is also able to stretch/squeeze the audio data to make it match
1324 the timestamps or to inject silence / cut out audio to make it match the
1325 timestamps, do a combination of both or do neither.
1327 The filter accepts the syntax
1328 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
1329 expresses a sample rate and @var{resampler_options} is a list of
1330 @var{key}=@var{value} pairs, separated by ":". See the
1331 ffmpeg-resampler manual for the complete list of supported options.
1333 @subsection Examples
1337 Resample the input audio to 44100Hz:
1343 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
1344 samples per second compensation:
1346 aresample=async=1000
1350 @section asetnsamples
1352 Set the number of samples per each output audio frame.
1354 The last output packet may contain a different number of samples, as
1355 the filter will flush all the remaining samples when the input audio
1358 The filter accepts the following options:
1362 @item nb_out_samples, n
1363 Set the number of frames per each output audio frame. The number is
1364 intended as the number of samples @emph{per each channel}.
1365 Default value is 1024.
1368 If set to 1, the filter will pad the last audio frame with zeroes, so
1369 that the last frame will contain the same number of samples as the
1370 previous ones. Default value is 1.
1373 For example, to set the number of per-frame samples to 1234 and
1374 disable padding for the last frame, use:
1376 asetnsamples=n=1234:p=0
1381 Set the sample rate without altering the PCM data.
1382 This will result in a change of speed and pitch.
1384 The filter accepts the following options:
1387 @item sample_rate, r
1388 Set the output sample rate. Default is 44100 Hz.
1393 Show a line containing various information for each input audio frame.
1394 The input audio is not modified.
1396 The shown line contains a sequence of key/value pairs of the form
1397 @var{key}:@var{value}.
1399 The following values are shown in the output:
1403 The (sequential) number of the input frame, starting from 0.
1406 The presentation timestamp of the input frame, in time base units; the time base
1407 depends on the filter input pad, and is usually 1/@var{sample_rate}.
1410 The presentation timestamp of the input frame in seconds.
1413 position of the frame in the input stream, -1 if this information in
1414 unavailable and/or meaningless (for example in case of synthetic audio)
1423 The sample rate for the audio frame.
1426 The number of samples (per channel) in the frame.
1429 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
1430 audio, the data is treated as if all the planes were concatenated.
1432 @item plane_checksums
1433 A list of Adler-32 checksums for each data plane.
1439 Display time domain statistical information about the audio channels.
1440 Statistics are calculated and displayed for each audio channel and,
1441 where applicable, an overall figure is also given.
1443 It accepts the following option:
1446 Short window length in seconds, used for peak and trough RMS measurement.
1447 Default is @code{0.05} (50 milliseconds). Allowed range is @code{[0.1 - 10]}.
1451 Set metadata injection. All the metadata keys are prefixed with @code{lavfi.astats.X},
1452 where @code{X} is channel number starting from 1 or string @code{Overall}. Default is
1455 Available keys for each channel are:
1486 For example full key look like this @code{lavfi.astats.1.DC_offset} or
1487 this @code{lavfi.astats.Overall.Peak_count}.
1489 For description what each key means read below.
1492 Set number of frame after which stats are going to be recalculated.
1493 Default is disabled.
1496 A description of each shown parameter follows:
1500 Mean amplitude displacement from zero.
1503 Minimal sample level.
1506 Maximal sample level.
1508 @item Min difference
1509 Minimal difference between two consecutive samples.
1511 @item Max difference
1512 Maximal difference between two consecutive samples.
1514 @item Mean difference
1515 Mean difference between two consecutive samples.
1516 The average of each difference between two consecutive samples.
1520 Standard peak and RMS level measured in dBFS.
1524 Peak and trough values for RMS level measured over a short window.
1527 Standard ratio of peak to RMS level (note: not in dB).
1530 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
1531 (i.e. either @var{Min level} or @var{Max level}).
1534 Number of occasions (not the number of samples) that the signal attained either
1535 @var{Min level} or @var{Max level}.
1538 Overall bit depth of audio. Number of bits used for each sample.
1543 Synchronize audio data with timestamps by squeezing/stretching it and/or
1544 dropping samples/adding silence when needed.
1546 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1548 It accepts the following parameters:
1552 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1553 by default. When disabled, time gaps are covered with silence.
1556 The minimum difference between timestamps and audio data (in seconds) to trigger
1557 adding/dropping samples. The default value is 0.1. If you get an imperfect
1558 sync with this filter, try setting this parameter to 0.
1561 The maximum compensation in samples per second. Only relevant with compensate=1.
1562 The default value is 500.
1565 Assume that the first PTS should be this value. The time base is 1 / sample
1566 rate. This allows for padding/trimming at the start of the stream. By default,
1567 no assumption is made about the first frame's expected PTS, so no padding or
1568 trimming is done. For example, this could be set to 0 to pad the beginning with
1569 silence if an audio stream starts after the video stream or to trim any samples
1570 with a negative PTS due to encoder delay.
1578 The filter accepts exactly one parameter, the audio tempo. If not
1579 specified then the filter will assume nominal 1.0 tempo. Tempo must
1580 be in the [0.5, 2.0] range.
1582 @subsection Examples
1586 Slow down audio to 80% tempo:
1592 To speed up audio to 125% tempo:
1600 Trim the input so that the output contains one continuous subpart of the input.
1602 It accepts the following parameters:
1605 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1606 sample with the timestamp @var{start} will be the first sample in the output.
1609 Specify time of the first audio sample that will be dropped, i.e. the
1610 audio sample immediately preceding the one with the timestamp @var{end} will be
1611 the last sample in the output.
1614 Same as @var{start}, except this option sets the start timestamp in samples
1618 Same as @var{end}, except this option sets the end timestamp in samples instead
1622 The maximum duration of the output in seconds.
1625 The number of the first sample that should be output.
1628 The number of the first sample that should be dropped.
1631 @option{start}, @option{end}, and @option{duration} are expressed as time
1632 duration specifications; see
1633 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
1635 Note that the first two sets of the start/end options and the @option{duration}
1636 option look at the frame timestamp, while the _sample options simply count the
1637 samples that pass through the filter. So start/end_pts and start/end_sample will
1638 give different results when the timestamps are wrong, inexact or do not start at
1639 zero. Also note that this filter does not modify the timestamps. If you wish
1640 to have the output timestamps start at zero, insert the asetpts filter after the
1643 If multiple start or end options are set, this filter tries to be greedy and
1644 keep all samples that match at least one of the specified constraints. To keep
1645 only the part that matches all the constraints at once, chain multiple atrim
1648 The defaults are such that all the input is kept. So it is possible to set e.g.
1649 just the end values to keep everything before the specified time.
1654 Drop everything except the second minute of input:
1656 ffmpeg -i INPUT -af atrim=60:120
1660 Keep only the first 1000 samples:
1662 ffmpeg -i INPUT -af atrim=end_sample=1000
1669 Apply a two-pole Butterworth band-pass filter with central
1670 frequency @var{frequency}, and (3dB-point) band-width width.
1671 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1672 instead of the default: constant 0dB peak gain.
1673 The filter roll off at 6dB per octave (20dB per decade).
1675 The filter accepts the following options:
1679 Set the filter's central frequency. Default is @code{3000}.
1682 Constant skirt gain if set to 1. Defaults to 0.
1685 Set method to specify band-width of filter.
1698 Specify the band-width of a filter in width_type units.
1703 Apply a two-pole Butterworth band-reject filter with central
1704 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1705 The filter roll off at 6dB per octave (20dB per decade).
1707 The filter accepts the following options:
1711 Set the filter's central frequency. Default is @code{3000}.
1714 Set method to specify band-width of filter.
1727 Specify the band-width of a filter in width_type units.
1732 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1733 shelving filter with a response similar to that of a standard
1734 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1736 The filter accepts the following options:
1740 Give the gain at 0 Hz. Its useful range is about -20
1741 (for a large cut) to +20 (for a large boost).
1742 Beware of clipping when using a positive gain.
1745 Set the filter's central frequency and so can be used
1746 to extend or reduce the frequency range to be boosted or cut.
1747 The default value is @code{100} Hz.
1750 Set method to specify band-width of filter.
1763 Determine how steep is the filter's shelf transition.
1768 Apply a biquad IIR filter with the given coefficients.
1769 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1770 are the numerator and denominator coefficients respectively.
1773 Bauer stereo to binaural transformation, which improves headphone listening of
1774 stereo audio records.
1776 It accepts the following parameters:
1780 Pre-defined crossfeed level.
1784 Default level (fcut=700, feed=50).
1787 Chu Moy circuit (fcut=700, feed=60).
1790 Jan Meier circuit (fcut=650, feed=95).
1795 Cut frequency (in Hz).
1804 Remap input channels to new locations.
1806 It accepts the following parameters:
1808 @item channel_layout
1809 The channel layout of the output stream.
1812 Map channels from input to output. The argument is a '|'-separated list of
1813 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1814 @var{in_channel} form. @var{in_channel} can be either the name of the input
1815 channel (e.g. FL for front left) or its index in the input channel layout.
1816 @var{out_channel} is the name of the output channel or its index in the output
1817 channel layout. If @var{out_channel} is not given then it is implicitly an
1818 index, starting with zero and increasing by one for each mapping.
1821 If no mapping is present, the filter will implicitly map input channels to
1822 output channels, preserving indices.
1824 For example, assuming a 5.1+downmix input MOV file,
1826 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1828 will create an output WAV file tagged as stereo from the downmix channels of
1831 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1833 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:5.1' out.wav
1836 @section channelsplit
1838 Split each channel from an input audio stream into a separate output stream.
1840 It accepts the following parameters:
1842 @item channel_layout
1843 The channel layout of the input stream. The default is "stereo".
1846 For example, assuming a stereo input MP3 file,
1848 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1850 will create an output Matroska file with two audio streams, one containing only
1851 the left channel and the other the right channel.
1853 Split a 5.1 WAV file into per-channel files:
1855 ffmpeg -i in.wav -filter_complex
1856 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1857 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1858 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1863 Add a chorus effect to the audio.
1865 Can make a single vocal sound like a chorus, but can also be applied to instrumentation.
1867 Chorus resembles an echo effect with a short delay, but whereas with echo the delay is
1868 constant, with chorus, it is varied using using sinusoidal or triangular modulation.
1869 The modulation depth defines the range the modulated delay is played before or after
1870 the delay. Hence the delayed sound will sound slower or faster, that is the delayed
1871 sound tuned around the original one, like in a chorus where some vocals are slightly
1874 It accepts the following parameters:
1877 Set input gain. Default is 0.4.
1880 Set output gain. Default is 0.4.
1883 Set delays. A typical delay is around 40ms to 60ms.
1895 @subsection Examples
1901 chorus=0.7:0.9:55:0.4:0.25:2
1907 chorus=0.6:0.9:50|60:0.4|0.32:0.25|0.4:2|1.3
1911 Fuller sounding chorus with three delays:
1913 chorus=0.5:0.9:50|60|40:0.4|0.32|0.3:0.25|0.4|0.3:2|2.3|1.3
1918 Compress or expand the audio's dynamic range.
1920 It accepts the following parameters:
1926 A list of times in seconds for each channel over which the instantaneous level
1927 of the input signal is averaged to determine its volume. @var{attacks} refers to
1928 increase of volume and @var{decays} refers to decrease of volume. For most
1929 situations, the attack time (response to the audio getting louder) should be
1930 shorter than the decay time, because the human ear is more sensitive to sudden
1931 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1932 a typical value for decay is 0.8 seconds.
1933 If specified number of attacks & decays is lower than number of channels, the last
1934 set attack/decay will be used for all remaining channels.
1937 A list of points for the transfer function, specified in dB relative to the
1938 maximum possible signal amplitude. Each key points list must be defined using
1939 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1940 @code{x0/y0 x1/y1 x2/y2 ....}
1942 The input values must be in strictly increasing order but the transfer function
1943 does not have to be monotonically rising. The point @code{0/0} is assumed but
1944 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1945 function are @code{-70/-70|-60/-20}.
1948 Set the curve radius in dB for all joints. It defaults to 0.01.
1951 Set the additional gain in dB to be applied at all points on the transfer
1952 function. This allows for easy adjustment of the overall gain.
1956 Set an initial volume, in dB, to be assumed for each channel when filtering
1957 starts. This permits the user to supply a nominal level initially, so that, for
1958 example, a very large gain is not applied to initial signal levels before the
1959 companding has begun to operate. A typical value for audio which is initially
1960 quiet is -90 dB. It defaults to 0.
1963 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1964 delayed before being fed to the volume adjuster. Specifying a delay
1965 approximately equal to the attack/decay times allows the filter to effectively
1966 operate in predictive rather than reactive mode. It defaults to 0.
1970 @subsection Examples
1974 Make music with both quiet and loud passages suitable for listening to in a
1977 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1980 Another example for audio with whisper and explosion parts:
1982 compand=0|0:1|1:-90/-900|-70/-70|-30/-9|0/-3:6:0:0:0
1986 A noise gate for when the noise is at a lower level than the signal:
1988 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1992 Here is another noise gate, this time for when the noise is at a higher level
1993 than the signal (making it, in some ways, similar to squelch):
1995 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1999 2:1 compression starting at -6dB:
2001 compand=points=-80/-80|-6/-6|0/-3.8|20/3.5
2005 2:1 compression starting at -9dB:
2007 compand=points=-80/-80|-9/-9|0/-5.3|20/2.9
2011 2:1 compression starting at -12dB:
2013 compand=points=-80/-80|-12/-12|0/-6.8|20/1.9
2017 2:1 compression starting at -18dB:
2019 compand=points=-80/-80|-18/-18|0/-9.8|20/0.7
2023 3:1 compression starting at -15dB:
2025 compand=points=-80/-80|-15/-15|0/-10.8|20/-5.2
2031 compand=points=-80/-105|-62/-80|-15.4/-15.4|0/-12|20/-7.6
2037 compand=attacks=0:points=-80/-169|-54/-80|-49.5/-64.6|-41.1/-41.1|-25.8/-15|-10.8/-4.5|0/0|20/8.3
2041 Hard limiter at -6dB:
2043 compand=attacks=0:points=-80/-80|-6/-6|20/-6
2047 Hard limiter at -12dB:
2049 compand=attacks=0:points=-80/-80|-12/-12|20/-12
2053 Hard noise gate at -35 dB:
2055 compand=attacks=0:points=-80/-115|-35.1/-80|-35/-35|20/20
2061 compand=attacks=0:points=-80/-80|-12.4/-12.4|-6/-8|0/-6.8|20/-2.8
2065 @section compensationdelay
2067 Compensation Delay Line is a metric based delay to compensate differing
2068 positions of microphones or speakers.
2070 For example, you have recorded guitar with two microphones placed in
2071 different location. Because the front of sound wave has fixed speed in
2072 normal conditions, the phasing of microphones can vary and depends on
2073 their location and interposition. The best sound mix can be achieved when
2074 these microphones are in phase (synchronized). Note that distance of
2075 ~30 cm between microphones makes one microphone to capture signal in
2076 antiphase to another microphone. That makes the final mix sounding moody.
2077 This filter helps to solve phasing problems by adding different delays
2078 to each microphone track and make them synchronized.
2080 The best result can be reached when you take one track as base and
2081 synchronize other tracks one by one with it.
2082 Remember that synchronization/delay tolerance depends on sample rate, too.
2083 Higher sample rates will give more tolerance.
2085 It accepts the following parameters:
2089 Set millimeters distance. This is compensation distance for fine tuning.
2093 Set cm distance. This is compensation distance for tightening distance setup.
2097 Set meters distance. This is compensation distance for hard distance setup.
2101 Set dry amount. Amount of unprocessed (dry) signal.
2105 Set wet amount. Amount of processed (wet) signal.
2109 Set temperature degree in Celsius. This is the temperature of the environment.
2114 Apply a DC shift to the audio.
2116 This can be useful to remove a DC offset (caused perhaps by a hardware problem
2117 in the recording chain) from the audio. The effect of a DC offset is reduced
2118 headroom and hence volume. The @ref{astats} filter can be used to determine if
2119 a signal has a DC offset.
2123 Set the DC shift, allowed range is [-1, 1]. It indicates the amount to shift
2127 Optional. It should have a value much less than 1 (e.g. 0.05 or 0.02) and is
2128 used to prevent clipping.
2132 Dynamic Audio Normalizer.
2134 This filter applies a certain amount of gain to the input audio in order
2135 to bring its peak magnitude to a target level (e.g. 0 dBFS). However, in
2136 contrast to more "simple" normalization algorithms, the Dynamic Audio
2137 Normalizer *dynamically* re-adjusts the gain factor to the input audio.
2138 This allows for applying extra gain to the "quiet" sections of the audio
2139 while avoiding distortions or clipping the "loud" sections. In other words:
2140 The Dynamic Audio Normalizer will "even out" the volume of quiet and loud
2141 sections, in the sense that the volume of each section is brought to the
2142 same target level. Note, however, that the Dynamic Audio Normalizer achieves
2143 this goal *without* applying "dynamic range compressing". It will retain 100%
2144 of the dynamic range *within* each section of the audio file.
2148 Set the frame length in milliseconds. In range from 10 to 8000 milliseconds.
2149 Default is 500 milliseconds.
2150 The Dynamic Audio Normalizer processes the input audio in small chunks,
2151 referred to as frames. This is required, because a peak magnitude has no
2152 meaning for just a single sample value. Instead, we need to determine the
2153 peak magnitude for a contiguous sequence of sample values. While a "standard"
2154 normalizer would simply use the peak magnitude of the complete file, the
2155 Dynamic Audio Normalizer determines the peak magnitude individually for each
2156 frame. The length of a frame is specified in milliseconds. By default, the
2157 Dynamic Audio Normalizer uses a frame length of 500 milliseconds, which has
2158 been found to give good results with most files.
2159 Note that the exact frame length, in number of samples, will be determined
2160 automatically, based on the sampling rate of the individual input audio file.
2163 Set the Gaussian filter window size. In range from 3 to 301, must be odd
2164 number. Default is 31.
2165 Probably the most important parameter of the Dynamic Audio Normalizer is the
2166 @code{window size} of the Gaussian smoothing filter. The filter's window size
2167 is specified in frames, centered around the current frame. For the sake of
2168 simplicity, this must be an odd number. Consequently, the default value of 31
2169 takes into account the current frame, as well as the 15 preceding frames and
2170 the 15 subsequent frames. Using a larger window results in a stronger
2171 smoothing effect and thus in less gain variation, i.e. slower gain
2172 adaptation. Conversely, using a smaller window results in a weaker smoothing
2173 effect and thus in more gain variation, i.e. faster gain adaptation.
2174 In other words, the more you increase this value, the more the Dynamic Audio
2175 Normalizer will behave like a "traditional" normalization filter. On the
2176 contrary, the more you decrease this value, the more the Dynamic Audio
2177 Normalizer will behave like a dynamic range compressor.
2180 Set the target peak value. This specifies the highest permissible magnitude
2181 level for the normalized audio input. This filter will try to approach the
2182 target peak magnitude as closely as possible, but at the same time it also
2183 makes sure that the normalized signal will never exceed the peak magnitude.
2184 A frame's maximum local gain factor is imposed directly by the target peak
2185 magnitude. The default value is 0.95 and thus leaves a headroom of 5%*.
2186 It is not recommended to go above this value.
2189 Set the maximum gain factor. In range from 1.0 to 100.0. Default is 10.0.
2190 The Dynamic Audio Normalizer determines the maximum possible (local) gain
2191 factor for each input frame, i.e. the maximum gain factor that does not
2192 result in clipping or distortion. The maximum gain factor is determined by
2193 the frame's highest magnitude sample. However, the Dynamic Audio Normalizer
2194 additionally bounds the frame's maximum gain factor by a predetermined
2195 (global) maximum gain factor. This is done in order to avoid excessive gain
2196 factors in "silent" or almost silent frames. By default, the maximum gain
2197 factor is 10.0, For most inputs the default value should be sufficient and
2198 it usually is not recommended to increase this value. Though, for input
2199 with an extremely low overall volume level, it may be necessary to allow even
2200 higher gain factors. Note, however, that the Dynamic Audio Normalizer does
2201 not simply apply a "hard" threshold (i.e. cut off values above the threshold).
2202 Instead, a "sigmoid" threshold function will be applied. This way, the
2203 gain factors will smoothly approach the threshold value, but never exceed that
2207 Set the target RMS. In range from 0.0 to 1.0. Default is 0.0 - disabled.
2208 By default, the Dynamic Audio Normalizer performs "peak" normalization.
2209 This means that the maximum local gain factor for each frame is defined
2210 (only) by the frame's highest magnitude sample. This way, the samples can
2211 be amplified as much as possible without exceeding the maximum signal
2212 level, i.e. without clipping. Optionally, however, the Dynamic Audio
2213 Normalizer can also take into account the frame's root mean square,
2214 abbreviated RMS. In electrical engineering, the RMS is commonly used to
2215 determine the power of a time-varying signal. It is therefore considered
2216 that the RMS is a better approximation of the "perceived loudness" than
2217 just looking at the signal's peak magnitude. Consequently, by adjusting all
2218 frames to a constant RMS value, a uniform "perceived loudness" can be
2219 established. If a target RMS value has been specified, a frame's local gain
2220 factor is defined as the factor that would result in exactly that RMS value.
2221 Note, however, that the maximum local gain factor is still restricted by the
2222 frame's highest magnitude sample, in order to prevent clipping.
2225 Enable channels coupling. By default is enabled.
2226 By default, the Dynamic Audio Normalizer will amplify all channels by the same
2227 amount. This means the same gain factor will be applied to all channels, i.e.
2228 the maximum possible gain factor is determined by the "loudest" channel.
2229 However, in some recordings, it may happen that the volume of the different
2230 channels is uneven, e.g. one channel may be "quieter" than the other one(s).
2231 In this case, this option can be used to disable the channel coupling. This way,
2232 the gain factor will be determined independently for each channel, depending
2233 only on the individual channel's highest magnitude sample. This allows for
2234 harmonizing the volume of the different channels.
2237 Enable DC bias correction. By default is disabled.
2238 An audio signal (in the time domain) is a sequence of sample values.
2239 In the Dynamic Audio Normalizer these sample values are represented in the
2240 -1.0 to 1.0 range, regardless of the original input format. Normally, the
2241 audio signal, or "waveform", should be centered around the zero point.
2242 That means if we calculate the mean value of all samples in a file, or in a
2243 single frame, then the result should be 0.0 or at least very close to that
2244 value. If, however, there is a significant deviation of the mean value from
2245 0.0, in either positive or negative direction, this is referred to as a
2246 DC bias or DC offset. Since a DC bias is clearly undesirable, the Dynamic
2247 Audio Normalizer provides optional DC bias correction.
2248 With DC bias correction enabled, the Dynamic Audio Normalizer will determine
2249 the mean value, or "DC correction" offset, of each input frame and subtract
2250 that value from all of the frame's sample values which ensures those samples
2251 are centered around 0.0 again. Also, in order to avoid "gaps" at the frame
2252 boundaries, the DC correction offset values will be interpolated smoothly
2253 between neighbouring frames.
2256 Enable alternative boundary mode. By default is disabled.
2257 The Dynamic Audio Normalizer takes into account a certain neighbourhood
2258 around each frame. This includes the preceding frames as well as the
2259 subsequent frames. However, for the "boundary" frames, located at the very
2260 beginning and at the very end of the audio file, not all neighbouring
2261 frames are available. In particular, for the first few frames in the audio
2262 file, the preceding frames are not known. And, similarly, for the last few
2263 frames in the audio file, the subsequent frames are not known. Thus, the
2264 question arises which gain factors should be assumed for the missing frames
2265 in the "boundary" region. The Dynamic Audio Normalizer implements two modes
2266 to deal with this situation. The default boundary mode assumes a gain factor
2267 of exactly 1.0 for the missing frames, resulting in a smooth "fade in" and
2268 "fade out" at the beginning and at the end of the input, respectively.
2271 Set the compress factor. In range from 0.0 to 30.0. Default is 0.0.
2272 By default, the Dynamic Audio Normalizer does not apply "traditional"
2273 compression. This means that signal peaks will not be pruned and thus the
2274 full dynamic range will be retained within each local neighbourhood. However,
2275 in some cases it may be desirable to combine the Dynamic Audio Normalizer's
2276 normalization algorithm with a more "traditional" compression.
2277 For this purpose, the Dynamic Audio Normalizer provides an optional compression
2278 (thresholding) function. If (and only if) the compression feature is enabled,
2279 all input frames will be processed by a soft knee thresholding function prior
2280 to the actual normalization process. Put simply, the thresholding function is
2281 going to prune all samples whose magnitude exceeds a certain threshold value.
2282 However, the Dynamic Audio Normalizer does not simply apply a fixed threshold
2283 value. Instead, the threshold value will be adjusted for each individual
2285 In general, smaller parameters result in stronger compression, and vice versa.
2286 Values below 3.0 are not recommended, because audible distortion may appear.
2291 Make audio easier to listen to on headphones.
2293 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
2294 so that when listened to on headphones the stereo image is moved from
2295 inside your head (standard for headphones) to outside and in front of
2296 the listener (standard for speakers).
2302 Apply a two-pole peaking equalisation (EQ) filter. With this
2303 filter, the signal-level at and around a selected frequency can
2304 be increased or decreased, whilst (unlike bandpass and bandreject
2305 filters) that at all other frequencies is unchanged.
2307 In order to produce complex equalisation curves, this filter can
2308 be given several times, each with a different central frequency.
2310 The filter accepts the following options:
2314 Set the filter's central frequency in Hz.
2317 Set method to specify band-width of filter.
2330 Specify the band-width of a filter in width_type units.
2333 Set the required gain or attenuation in dB.
2334 Beware of clipping when using a positive gain.
2337 @subsection Examples
2340 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
2342 equalizer=f=1000:width_type=h:width=200:g=-10
2346 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
2348 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
2352 @section extrastereo
2354 Linearly increases the difference between left and right channels which
2355 adds some sort of "live" effect to playback.
2357 The filter accepts the following option:
2361 Sets the difference coefficient (default: 2.5). 0.0 means mono sound
2362 (average of both channels), with 1.0 sound will be unchanged, with
2363 -1.0 left and right channels will be swapped.
2366 Enable clipping. By default is enabled.
2369 @section firequalizer
2370 Apply FIR Equalization using arbitrary frequency response.
2372 The filter accepts the following option:
2376 Set gain curve equation (in dB). The expression can contain variables:
2379 the evaluated frequency
2383 channel number, set to 0 when multichannels evaluation is disabled
2385 channel id, see libavutil/channel_layout.h, set to the first channel id when
2386 multichannels evaluation is disabled
2390 channel_layout, see libavutil/channel_layout.h
2395 @item gain_interpolate(f)
2396 interpolate gain on frequency f based on gain_entry
2398 This option is also available as command. Default is @code{gain_interpolate(f)}.
2401 Set gain entry for gain_interpolate function. The expression can
2405 store gain entry at frequency f with value g
2407 This option is also available as command.
2410 Set filter delay in seconds. Higher value means more accurate.
2411 Default is @code{0.01}.
2414 Set filter accuracy in Hz. Lower value means more accurate.
2415 Default is @code{5}.
2418 Set window function. Acceptable values are:
2421 rectangular window, useful when gain curve is already smooth
2423 hann window (default)
2429 3-terms continuous 1st derivative nuttall window
2431 minimum 3-terms discontinuous nuttall window
2433 4-terms continuous 1st derivative nuttall window
2435 minimum 4-terms discontinuous nuttall (blackman-nuttall) window
2437 blackman-harris window
2441 If enabled, use fixed number of audio samples. This improves speed when
2442 filtering with large delay. Default is disabled.
2445 Enable multichannels evaluation on gain. Default is disabled.
2448 @subsection Examples
2453 firequalizer=gain='if(lt(f,1000), 0, -INF)'
2456 lowpass at 1000 Hz with gain_entry:
2458 firequalizer=gain_entry='entry(1000,0); entry(1001, -INF)'
2461 custom equalization:
2463 firequalizer=gain_entry='entry(100,0); entry(400, -4); entry(1000, -6); entry(2000, 0)'
2468 firequalizer=delay=0.1:fixed=on
2471 lowpass on left channel, highpass on right channel:
2473 firequalizer=gain='if(eq(chid,1), gain_interpolate(f), if(eq(chid,2), gain_interpolate(1e6+f), 0))'
2474 :gain_entry='entry(1000, 0); entry(1001,-INF); entry(1e6+1000,0)':multi=on
2479 Apply a flanging effect to the audio.
2481 The filter accepts the following options:
2485 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
2488 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
2491 Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
2495 Set percentage of delayed signal mixed with original. Range from 0 to 100.
2496 Default value is 71.
2499 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
2502 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
2503 Default value is @var{sinusoidal}.
2506 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
2507 Default value is 25.
2510 Set delay-line interpolation, @var{linear} or @var{quadratic}.
2511 Default is @var{linear}.
2516 Apply a high-pass filter with 3dB point frequency.
2517 The filter can be either single-pole, or double-pole (the default).
2518 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2520 The filter accepts the following options:
2524 Set frequency in Hz. Default is 3000.
2527 Set number of poles. Default is 2.
2530 Set method to specify band-width of filter.
2543 Specify the band-width of a filter in width_type units.
2544 Applies only to double-pole filter.
2545 The default is 0.707q and gives a Butterworth response.
2550 Join multiple input streams into one multi-channel stream.
2552 It accepts the following parameters:
2556 The number of input streams. It defaults to 2.
2558 @item channel_layout
2559 The desired output channel layout. It defaults to stereo.
2562 Map channels from inputs to output. The argument is a '|'-separated list of
2563 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
2564 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
2565 can be either the name of the input channel (e.g. FL for front left) or its
2566 index in the specified input stream. @var{out_channel} is the name of the output
2570 The filter will attempt to guess the mappings when they are not specified
2571 explicitly. It does so by first trying to find an unused matching input channel
2572 and if that fails it picks the first unused input channel.
2574 Join 3 inputs (with properly set channel layouts):
2576 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
2579 Build a 5.1 output from 6 single-channel streams:
2581 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
2582 'join=inputs=6:channel_layout=5.1:map=0.0-FL|1.0-FR|2.0-FC|3.0-SL|4.0-SR|5.0-LFE'
2588 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
2590 To enable compilation of this filter you need to configure FFmpeg with
2591 @code{--enable-ladspa}.
2595 Specifies the name of LADSPA plugin library to load. If the environment
2596 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
2597 each one of the directories specified by the colon separated list in
2598 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
2599 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
2600 @file{/usr/lib/ladspa/}.
2603 Specifies the plugin within the library. Some libraries contain only
2604 one plugin, but others contain many of them. If this is not set filter
2605 will list all available plugins within the specified library.
2608 Set the '|' separated list of controls which are zero or more floating point
2609 values that determine the behavior of the loaded plugin (for example delay,
2611 Controls need to be defined using the following syntax:
2612 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
2613 @var{valuei} is the value set on the @var{i}-th control.
2614 Alternatively they can be also defined using the following syntax:
2615 @var{value0}|@var{value1}|@var{value2}|..., where
2616 @var{valuei} is the value set on the @var{i}-th control.
2617 If @option{controls} is set to @code{help}, all available controls and
2618 their valid ranges are printed.
2620 @item sample_rate, s
2621 Specify the sample rate, default to 44100. Only used if plugin have
2625 Set the number of samples per channel per each output frame, default
2626 is 1024. Only used if plugin have zero inputs.
2629 Set the minimum duration of the sourced audio. See
2630 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2631 for the accepted syntax.
2632 Note that the resulting duration may be greater than the specified duration,
2633 as the generated audio is always cut at the end of a complete frame.
2634 If not specified, or the expressed duration is negative, the audio is
2635 supposed to be generated forever.
2636 Only used if plugin have zero inputs.
2640 @subsection Examples
2644 List all available plugins within amp (LADSPA example plugin) library:
2650 List all available controls and their valid ranges for @code{vcf_notch}
2651 plugin from @code{VCF} library:
2653 ladspa=f=vcf:p=vcf_notch:c=help
2657 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
2660 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
2664 Add reverberation to the audio using TAP-plugins
2665 (Tom's Audio Processing plugins):
2667 ladspa=file=tap_reverb:tap_reverb
2671 Generate white noise, with 0.2 amplitude:
2673 ladspa=file=cmt:noise_source_white:c=c0=.2
2677 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
2678 @code{C* Audio Plugin Suite} (CAPS) library:
2680 ladspa=file=caps:Click:c=c1=20'
2684 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
2686 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
2690 Increase volume by 20dB using fast lookahead limiter from Steve Harris
2691 @code{SWH Plugins} collection:
2693 ladspa=fast_lookahead_limiter_1913:fastLookaheadLimiter:20|0|2
2697 Attenuate low frequencies using Multiband EQ from Steve Harris
2698 @code{SWH Plugins} collection:
2700 ladspa=mbeq_1197:mbeq:-24|-24|-24|0|0|0|0|0|0|0|0|0|0|0|0
2704 @subsection Commands
2706 This filter supports the following commands:
2709 Modify the @var{N}-th control value.
2711 If the specified value is not valid, it is ignored and prior one is kept.
2716 Apply a low-pass filter with 3dB point frequency.
2717 The filter can be either single-pole or double-pole (the default).
2718 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2720 The filter accepts the following options:
2724 Set frequency in Hz. Default is 500.
2727 Set number of poles. Default is 2.
2730 Set method to specify band-width of filter.
2743 Specify the band-width of a filter in width_type units.
2744 Applies only to double-pole filter.
2745 The default is 0.707q and gives a Butterworth response.
2751 Mix channels with specific gain levels. The filter accepts the output
2752 channel layout followed by a set of channels definitions.
2754 This filter is also designed to efficiently remap the channels of an audio
2757 The filter accepts parameters of the form:
2758 "@var{l}|@var{outdef}|@var{outdef}|..."
2762 output channel layout or number of channels
2765 output channel specification, of the form:
2766 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
2769 output channel to define, either a channel name (FL, FR, etc.) or a channel
2770 number (c0, c1, etc.)
2773 multiplicative coefficient for the channel, 1 leaving the volume unchanged
2776 input channel to use, see out_name for details; it is not possible to mix
2777 named and numbered input channels
2780 If the `=' in a channel specification is replaced by `<', then the gains for
2781 that specification will be renormalized so that the total is 1, thus
2782 avoiding clipping noise.
2784 @subsection Mixing examples
2786 For example, if you want to down-mix from stereo to mono, but with a bigger
2787 factor for the left channel:
2789 pan=1c|c0=0.9*c0+0.1*c1
2792 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
2793 7-channels surround:
2795 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
2798 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
2799 that should be preferred (see "-ac" option) unless you have very specific
2802 @subsection Remapping examples
2804 The channel remapping will be effective if, and only if:
2807 @item gain coefficients are zeroes or ones,
2808 @item only one input per channel output,
2811 If all these conditions are satisfied, the filter will notify the user ("Pure
2812 channel mapping detected"), and use an optimized and lossless method to do the
2815 For example, if you have a 5.1 source and want a stereo audio stream by
2816 dropping the extra channels:
2818 pan="stereo| c0=FL | c1=FR"
2821 Given the same source, you can also switch front left and front right channels
2822 and keep the input channel layout:
2824 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
2827 If the input is a stereo audio stream, you can mute the front left channel (and
2828 still keep the stereo channel layout) with:
2833 Still with a stereo audio stream input, you can copy the right channel in both
2834 front left and right:
2836 pan="stereo| c0=FR | c1=FR"
2841 ReplayGain scanner filter. This filter takes an audio stream as an input and
2842 outputs it unchanged.
2843 At end of filtering it displays @code{track_gain} and @code{track_peak}.
2847 Convert the audio sample format, sample rate and channel layout. It is
2848 not meant to be used directly.
2851 Apply time-stretching and pitch-shifting with librubberband.
2853 The filter accepts the following options:
2857 Set tempo scale factor.
2860 Set pitch scale factor.
2863 Set transients detector.
2864 Possible values are:
2873 Possible values are:
2882 Possible values are:
2889 Set processing window size.
2890 Possible values are:
2899 Possible values are:
2906 Enable formant preservation when shift pitching.
2907 Possible values are:
2915 Possible values are:
2924 Possible values are:
2931 @section sidechaincompress
2933 This filter acts like normal compressor but has the ability to compress
2934 detected signal using second input signal.
2935 It needs two input streams and returns one output stream.
2936 First input stream will be processed depending on second stream signal.
2937 The filtered signal then can be filtered with other filters in later stages of
2938 processing. See @ref{pan} and @ref{amerge} filter.
2940 The filter accepts the following options:
2944 Set input gain. Default is 1. Range is between 0.015625 and 64.
2947 If a signal of second stream raises above this level it will affect the gain
2948 reduction of first stream.
2949 By default is 0.125. Range is between 0.00097563 and 1.
2952 Set a ratio about which the signal is reduced. 1:2 means that if the level
2953 raised 4dB above the threshold, it will be only 2dB above after the reduction.
2954 Default is 2. Range is between 1 and 20.
2957 Amount of milliseconds the signal has to rise above the threshold before gain
2958 reduction starts. Default is 20. Range is between 0.01 and 2000.
2961 Amount of milliseconds the signal has to fall below the threshold before
2962 reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
2965 Set the amount by how much signal will be amplified after processing.
2966 Default is 2. Range is from 1 and 64.
2969 Curve the sharp knee around the threshold to enter gain reduction more softly.
2970 Default is 2.82843. Range is between 1 and 8.
2973 Choose if the @code{average} level between all channels of side-chain stream
2974 or the louder(@code{maximum}) channel of side-chain stream affects the
2975 reduction. Default is @code{average}.
2978 Should the exact signal be taken in case of @code{peak} or an RMS one in case
2979 of @code{rms}. Default is @code{rms} which is mainly smoother.
2982 Set sidechain gain. Default is 1. Range is between 0.015625 and 64.
2985 How much to use compressed signal in output. Default is 1.
2986 Range is between 0 and 1.
2989 @subsection Examples
2993 Full ffmpeg example taking 2 audio inputs, 1st input to be compressed
2994 depending on the signal of 2nd input and later compressed signal to be
2995 merged with 2nd input:
2997 ffmpeg -i main.flac -i sidechain.flac -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress[compr];[compr][mix]amerge"
3001 @section sidechaingate
3003 A sidechain gate acts like a normal (wideband) gate but has the ability to
3004 filter the detected signal before sending it to the gain reduction stage.
3005 Normally a gate uses the full range signal to detect a level above the
3007 For example: If you cut all lower frequencies from your sidechain signal
3008 the gate will decrease the volume of your track only if not enough highs
3009 appear. With this technique you are able to reduce the resonation of a
3010 natural drum or remove "rumbling" of muted strokes from a heavily distorted
3012 It needs two input streams and returns one output stream.
3013 First input stream will be processed depending on second stream signal.
3015 The filter accepts the following options:
3019 Set input level before filtering.
3020 Default is 1. Allowed range is from 0.015625 to 64.
3023 Set the level of gain reduction when the signal is below the threshold.
3024 Default is 0.06125. Allowed range is from 0 to 1.
3027 If a signal rises above this level the gain reduction is released.
3028 Default is 0.125. Allowed range is from 0 to 1.
3031 Set a ratio about which the signal is reduced.
3032 Default is 2. Allowed range is from 1 to 9000.
3035 Amount of milliseconds the signal has to rise above the threshold before gain
3037 Default is 20 milliseconds. Allowed range is from 0.01 to 9000.
3040 Amount of milliseconds the signal has to fall below the threshold before the
3041 reduction is increased again. Default is 250 milliseconds.
3042 Allowed range is from 0.01 to 9000.
3045 Set amount of amplification of signal after processing.
3046 Default is 1. Allowed range is from 1 to 64.
3049 Curve the sharp knee around the threshold to enter gain reduction more softly.
3050 Default is 2.828427125. Allowed range is from 1 to 8.
3053 Choose if exact signal should be taken for detection or an RMS like one.
3054 Default is rms. Can be peak or rms.
3057 Choose if the average level between all channels or the louder channel affects
3059 Default is average. Can be average or maximum.
3062 Set sidechain gain. Default is 1. Range is from 0.015625 to 64.
3065 @section silencedetect
3067 Detect silence in an audio stream.
3069 This filter logs a message when it detects that the input audio volume is less
3070 or equal to a noise tolerance value for a duration greater or equal to the
3071 minimum detected noise duration.
3073 The printed times and duration are expressed in seconds.
3075 The filter accepts the following options:
3079 Set silence duration until notification (default is 2 seconds).
3082 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
3083 specified value) or amplitude ratio. Default is -60dB, or 0.001.
3086 @subsection Examples
3090 Detect 5 seconds of silence with -50dB noise tolerance:
3092 silencedetect=n=-50dB:d=5
3096 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
3097 tolerance in @file{silence.mp3}:
3099 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
3103 @section silenceremove
3105 Remove silence from the beginning, middle or end of the audio.
3107 The filter accepts the following options:
3111 This value is used to indicate if audio should be trimmed at beginning of
3112 the audio. A value of zero indicates no silence should be trimmed from the
3113 beginning. When specifying a non-zero value, it trims audio up until it
3114 finds non-silence. Normally, when trimming silence from beginning of audio
3115 the @var{start_periods} will be @code{1} but it can be increased to higher
3116 values to trim all audio up to specific count of non-silence periods.
3117 Default value is @code{0}.
3119 @item start_duration
3120 Specify the amount of time that non-silence must be detected before it stops
3121 trimming audio. By increasing the duration, bursts of noises can be treated
3122 as silence and trimmed off. Default value is @code{0}.
3124 @item start_threshold
3125 This indicates what sample value should be treated as silence. For digital
3126 audio, a value of @code{0} may be fine but for audio recorded from analog,
3127 you may wish to increase the value to account for background noise.
3128 Can be specified in dB (in case "dB" is appended to the specified value)
3129 or amplitude ratio. Default value is @code{0}.
3132 Set the count for trimming silence from the end of audio.
3133 To remove silence from the middle of a file, specify a @var{stop_periods}
3134 that is negative. This value is then treated as a positive value and is
3135 used to indicate the effect should restart processing as specified by
3136 @var{start_periods}, making it suitable for removing periods of silence
3137 in the middle of the audio.
3138 Default value is @code{0}.
3141 Specify a duration of silence that must exist before audio is not copied any
3142 more. By specifying a higher duration, silence that is wanted can be left in
3144 Default value is @code{0}.
3146 @item stop_threshold
3147 This is the same as @option{start_threshold} but for trimming silence from
3149 Can be specified in dB (in case "dB" is appended to the specified value)
3150 or amplitude ratio. Default value is @code{0}.
3153 This indicate that @var{stop_duration} length of audio should be left intact
3154 at the beginning of each period of silence.
3155 For example, if you want to remove long pauses between words but do not want
3156 to remove the pauses completely. Default value is @code{0}.
3159 Set how is silence detected. Can be @code{rms} or @code{peak}. Second is faster
3160 and works better with digital silence which is exactly 0.
3161 Default value is @code{rms}.
3164 Set ratio used to calculate size of window for detecting silence.
3165 Default value is @code{0.02}. Allowed range is from @code{0} to @code{10}.
3168 @subsection Examples
3172 The following example shows how this filter can be used to start a recording
3173 that does not contain the delay at the start which usually occurs between
3174 pressing the record button and the start of the performance:
3176 silenceremove=1:5:0.02
3180 Trim all silence encountered from begining to end where there is more than 1
3181 second of silence in audio:
3183 silenceremove=0:0:0:-1:1:-90dB
3189 SOFAlizer uses head-related transfer functions (HRTFs) to create virtual
3190 loudspeakers around the user for binaural listening via headphones (audio
3191 formats up to 9 channels supported).
3192 The HRTFs are stored in SOFA files (see @url{http://www.sofacoustics.org/} for a database).
3193 SOFAlizer is developed at the Acoustics Research Institute (ARI) of the
3194 Austrian Academy of Sciences.
3196 To enable compilation of this filter you need to configure FFmpeg with
3197 @code{--enable-netcdf}.
3199 The filter accepts the following options:
3203 Set the SOFA file used for rendering.
3206 Set gain applied to audio. Value is in dB. Default is 0.
3209 Set rotation of virtual loudspeakers in deg. Default is 0.
3212 Set elevation of virtual speakers in deg. Default is 0.
3215 Set distance in meters between loudspeakers and the listener with near-field
3216 HRTFs. Default is 1.
3219 Set processing type. Can be @var{time} or @var{freq}. @var{time} is
3220 processing audio in time domain which is slow.
3221 @var{freq} is processing audio in frequency domain which is fast.
3222 Default is @var{freq}.
3225 Set custom positions of virtual loudspeakers. Syntax for this option is:
3226 <CH> <AZIM> <ELEV>[|<CH> <AZIM> <ELEV>|...].
3227 Each virtual loudspeaker is described with short channel name following with
3228 azimuth and elevation in degreees.
3229 Each virtual loudspeaker description is separated by '|'.
3230 For example to override front left and front right channel positions use:
3231 'speakers=FL 45 15|FR 345 15'.
3232 Descriptions with unrecognised channel names are ignored.
3235 @subsection Examples
3239 Using ClubFritz6 sofa file:
3241 sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=1
3245 Using ClubFritz12 sofa file and bigger radius with small rotation:
3247 sofalizer=sofa=/path/to/ClubFritz12.sofa:type=freq:radius=2:rotation=5
3251 Similar as above but with custom speaker positions for front left, front right, rear left and rear right
3252 and also with custom gain:
3254 "sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=2:speakers=FL 45|FR 315|RL 135|RR 225:gain=28"
3258 @section stereotools
3260 This filter has some handy utilities to manage stereo signals, for converting
3261 M/S stereo recordings to L/R signal while having control over the parameters
3262 or spreading the stereo image of master track.
3264 The filter accepts the following options:
3268 Set input level before filtering for both channels. Defaults is 1.
3269 Allowed range is from 0.015625 to 64.
3272 Set output level after filtering for both channels. Defaults is 1.
3273 Allowed range is from 0.015625 to 64.
3276 Set input balance between both channels. Default is 0.
3277 Allowed range is from -1 to 1.
3280 Set output balance between both channels. Default is 0.
3281 Allowed range is from -1 to 1.
3284 Enable softclipping. Results in analog distortion instead of harsh digital 0dB
3285 clipping. Disabled by default.
3288 Mute the left channel. Disabled by default.
3291 Mute the right channel. Disabled by default.
3294 Change the phase of the left channel. Disabled by default.
3297 Change the phase of the right channel. Disabled by default.
3300 Set stereo mode. Available values are:
3304 Left/Right to Left/Right, this is default.
3307 Left/Right to Mid/Side.
3310 Mid/Side to Left/Right.
3313 Left/Right to Left/Left.
3316 Left/Right to Right/Right.
3319 Left/Right to Left + Right.
3322 Left/Right to Right/Left.
3326 Set level of side signal. Default is 1.
3327 Allowed range is from 0.015625 to 64.
3330 Set balance of side signal. Default is 0.
3331 Allowed range is from -1 to 1.
3334 Set level of the middle signal. Default is 1.
3335 Allowed range is from 0.015625 to 64.
3338 Set middle signal pan. Default is 0. Allowed range is from -1 to 1.
3341 Set stereo base between mono and inversed channels. Default is 0.
3342 Allowed range is from -1 to 1.
3345 Set delay in milliseconds how much to delay left from right channel and
3346 vice versa. Default is 0. Allowed range is from -20 to 20.
3349 Set S/C level. Default is 1. Allowed range is from 1 to 100.
3352 Set the stereo phase in degrees. Default is 0. Allowed range is from 0 to 360.
3355 @subsection Examples
3359 Apply karaoke like effect:
3361 stereotools=mlev=0.015625
3365 Convert M/S signal to L/R:
3367 "stereotools=mode=ms>lr"
3371 @section stereowiden
3373 This filter enhance the stereo effect by suppressing signal common to both
3374 channels and by delaying the signal of left into right and vice versa,
3375 thereby widening the stereo effect.
3377 The filter accepts the following options:
3381 Time in milliseconds of the delay of left signal into right and vice versa.
3382 Default is 20 milliseconds.
3385 Amount of gain in delayed signal into right and vice versa. Gives a delay
3386 effect of left signal in right output and vice versa which gives widening
3387 effect. Default is 0.3.
3390 Cross feed of left into right with inverted phase. This helps in suppressing
3391 the mono. If the value is 1 it will cancel all the signal common to both
3392 channels. Default is 0.3.
3395 Set level of input signal of original channel. Default is 0.8.
3400 Boost or cut treble (upper) frequencies of the audio using a two-pole
3401 shelving filter with a response similar to that of a standard
3402 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
3404 The filter accepts the following options:
3408 Give the gain at whichever is the lower of ~22 kHz and the
3409 Nyquist frequency. Its useful range is about -20 (for a large cut)
3410 to +20 (for a large boost). Beware of clipping when using a positive gain.
3413 Set the filter's central frequency and so can be used
3414 to extend or reduce the frequency range to be boosted or cut.
3415 The default value is @code{3000} Hz.
3418 Set method to specify band-width of filter.
3431 Determine how steep is the filter's shelf transition.
3436 Sinusoidal amplitude modulation.
3438 The filter accepts the following options:
3442 Modulation frequency in Hertz. Modulation frequencies in the subharmonic range
3443 (20 Hz or lower) will result in a tremolo effect.
3444 This filter may also be used as a ring modulator by specifying
3445 a modulation frequency higher than 20 Hz.
3446 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
3449 Depth of modulation as a percentage. Range is 0.0 - 1.0.
3450 Default value is 0.5.
3455 Sinusoidal phase modulation.
3457 The filter accepts the following options:
3461 Modulation frequency in Hertz.
3462 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
3465 Depth of modulation as a percentage. Range is 0.0 - 1.0.
3466 Default value is 0.5.
3471 Adjust the input audio volume.
3473 It accepts the following parameters:
3477 Set audio volume expression.
3479 Output values are clipped to the maximum value.
3481 The output audio volume is given by the relation:
3483 @var{output_volume} = @var{volume} * @var{input_volume}
3486 The default value for @var{volume} is "1.0".
3489 This parameter represents the mathematical precision.
3491 It determines which input sample formats will be allowed, which affects the
3492 precision of the volume scaling.
3496 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
3498 32-bit floating-point; this limits input sample format to FLT. (default)
3500 64-bit floating-point; this limits input sample format to DBL.
3504 Choose the behaviour on encountering ReplayGain side data in input frames.
3508 Remove ReplayGain side data, ignoring its contents (the default).
3511 Ignore ReplayGain side data, but leave it in the frame.
3514 Prefer the track gain, if present.
3517 Prefer the album gain, if present.
3520 @item replaygain_preamp
3521 Pre-amplification gain in dB to apply to the selected replaygain gain.
3523 Default value for @var{replaygain_preamp} is 0.0.
3526 Set when the volume expression is evaluated.
3528 It accepts the following values:
3531 only evaluate expression once during the filter initialization, or
3532 when the @samp{volume} command is sent
3535 evaluate expression for each incoming frame
3538 Default value is @samp{once}.
3541 The volume expression can contain the following parameters.
3545 frame number (starting at zero)
3548 @item nb_consumed_samples
3549 number of samples consumed by the filter
3551 number of samples in the current frame
3553 original frame position in the file
3559 PTS at start of stream
3561 time at start of stream
3567 last set volume value
3570 Note that when @option{eval} is set to @samp{once} only the
3571 @var{sample_rate} and @var{tb} variables are available, all other
3572 variables will evaluate to NAN.
3574 @subsection Commands
3576 This filter supports the following commands:
3579 Modify the volume expression.
3580 The command accepts the same syntax of the corresponding option.
3582 If the specified expression is not valid, it is kept at its current
3584 @item replaygain_noclip
3585 Prevent clipping by limiting the gain applied.
3587 Default value for @var{replaygain_noclip} is 1.
3591 @subsection Examples
3595 Halve the input audio volume:
3599 volume=volume=-6.0206dB
3602 In all the above example the named key for @option{volume} can be
3603 omitted, for example like in:
3609 Increase input audio power by 6 decibels using fixed-point precision:
3611 volume=volume=6dB:precision=fixed
3615 Fade volume after time 10 with an annihilation period of 5 seconds:
3617 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
3621 @section volumedetect
3623 Detect the volume of the input video.
3625 The filter has no parameters. The input is not modified. Statistics about
3626 the volume will be printed in the log when the input stream end is reached.
3628 In particular it will show the mean volume (root mean square), maximum
3629 volume (on a per-sample basis), and the beginning of a histogram of the
3630 registered volume values (from the maximum value to a cumulated 1/1000 of
3633 All volumes are in decibels relative to the maximum PCM value.
3635 @subsection Examples
3637 Here is an excerpt of the output:
3639 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
3640 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
3641 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
3642 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
3643 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
3644 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
3645 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
3646 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
3647 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
3653 The mean square energy is approximately -27 dB, or 10^-2.7.
3655 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
3657 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
3660 In other words, raising the volume by +4 dB does not cause any clipping,
3661 raising it by +5 dB causes clipping for 6 samples, etc.
3663 @c man end AUDIO FILTERS
3665 @chapter Audio Sources
3666 @c man begin AUDIO SOURCES
3668 Below is a description of the currently available audio sources.
3672 Buffer audio frames, and make them available to the filter chain.
3674 This source is mainly intended for a programmatic use, in particular
3675 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
3677 It accepts the following parameters:
3681 The timebase which will be used for timestamps of submitted frames. It must be
3682 either a floating-point number or in @var{numerator}/@var{denominator} form.
3685 The sample rate of the incoming audio buffers.
3688 The sample format of the incoming audio buffers.
3689 Either a sample format name or its corresponding integer representation from
3690 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
3692 @item channel_layout
3693 The channel layout of the incoming audio buffers.
3694 Either a channel layout name from channel_layout_map in
3695 @file{libavutil/channel_layout.c} or its corresponding integer representation
3696 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
3699 The number of channels of the incoming audio buffers.
3700 If both @var{channels} and @var{channel_layout} are specified, then they
3705 @subsection Examples
3708 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
3711 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
3712 Since the sample format with name "s16p" corresponds to the number
3713 6 and the "stereo" channel layout corresponds to the value 0x3, this is
3716 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
3721 Generate an audio signal specified by an expression.
3723 This source accepts in input one or more expressions (one for each
3724 channel), which are evaluated and used to generate a corresponding
3727 This source accepts the following options:
3731 Set the '|'-separated expressions list for each separate channel. In case the
3732 @option{channel_layout} option is not specified, the selected channel layout
3733 depends on the number of provided expressions. Otherwise the last
3734 specified expression is applied to the remaining output channels.
3736 @item channel_layout, c
3737 Set the channel layout. The number of channels in the specified layout
3738 must be equal to the number of specified expressions.
3741 Set the minimum duration of the sourced audio. See
3742 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
3743 for the accepted syntax.
3744 Note that the resulting duration may be greater than the specified
3745 duration, as the generated audio is always cut at the end of a
3748 If not specified, or the expressed duration is negative, the audio is
3749 supposed to be generated forever.
3752 Set the number of samples per channel per each output frame,
3755 @item sample_rate, s
3756 Specify the sample rate, default to 44100.
3759 Each expression in @var{exprs} can contain the following constants:
3763 number of the evaluated sample, starting from 0
3766 time of the evaluated sample expressed in seconds, starting from 0
3773 @subsection Examples
3783 Generate a sin signal with frequency of 440 Hz, set sample rate to
3786 aevalsrc="sin(440*2*PI*t):s=8000"
3790 Generate a two channels signal, specify the channel layout (Front
3791 Center + Back Center) explicitly:
3793 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
3797 Generate white noise:
3799 aevalsrc="-2+random(0)"
3803 Generate an amplitude modulated signal:
3805 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
3809 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
3811 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
3818 The null audio source, return unprocessed audio frames. It is mainly useful
3819 as a template and to be employed in analysis / debugging tools, or as
3820 the source for filters which ignore the input data (for example the sox
3823 This source accepts the following options:
3827 @item channel_layout, cl
3829 Specifies the channel layout, and can be either an integer or a string
3830 representing a channel layout. The default value of @var{channel_layout}
3833 Check the channel_layout_map definition in
3834 @file{libavutil/channel_layout.c} for the mapping between strings and
3835 channel layout values.
3837 @item sample_rate, r
3838 Specifies the sample rate, and defaults to 44100.
3841 Set the number of samples per requested frames.
3845 @subsection Examples
3849 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
3851 anullsrc=r=48000:cl=4
3855 Do the same operation with a more obvious syntax:
3857 anullsrc=r=48000:cl=mono
3861 All the parameters need to be explicitly defined.
3865 Synthesize a voice utterance using the libflite library.
3867 To enable compilation of this filter you need to configure FFmpeg with
3868 @code{--enable-libflite}.
3870 Note that the flite library is not thread-safe.
3872 The filter accepts the following options:
3877 If set to 1, list the names of the available voices and exit
3878 immediately. Default value is 0.
3881 Set the maximum number of samples per frame. Default value is 512.
3884 Set the filename containing the text to speak.
3887 Set the text to speak.
3890 Set the voice to use for the speech synthesis. Default value is
3891 @code{kal}. See also the @var{list_voices} option.
3894 @subsection Examples
3898 Read from file @file{speech.txt}, and synthesize the text using the
3899 standard flite voice:
3901 flite=textfile=speech.txt
3905 Read the specified text selecting the @code{slt} voice:
3907 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
3911 Input text to ffmpeg:
3913 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
3917 Make @file{ffplay} speak the specified text, using @code{flite} and
3918 the @code{lavfi} device:
3920 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
3924 For more information about libflite, check:
3925 @url{http://www.speech.cs.cmu.edu/flite/}
3929 Generate a noise audio signal.
3931 The filter accepts the following options:
3934 @item sample_rate, r
3935 Specify the sample rate. Default value is 48000 Hz.
3938 Specify the amplitude (0.0 - 1.0) of the generated audio stream. Default value
3942 Specify the duration of the generated audio stream. Not specifying this option
3943 results in noise with an infinite length.
3945 @item color, colour, c
3946 Specify the color of noise. Available noise colors are white, pink, and brown.
3947 Default color is white.
3950 Specify a value used to seed the PRNG.
3953 Set the number of samples per each output frame, default is 1024.
3956 @subsection Examples
3961 Generate 60 seconds of pink noise, with a 44.1 kHz sampling rate and an amplitude of 0.5:
3963 anoisesrc=d=60:c=pink:r=44100:a=0.5
3969 Generate an audio signal made of a sine wave with amplitude 1/8.
3971 The audio signal is bit-exact.
3973 The filter accepts the following options:
3978 Set the carrier frequency. Default is 440 Hz.
3980 @item beep_factor, b
3981 Enable a periodic beep every second with frequency @var{beep_factor} times
3982 the carrier frequency. Default is 0, meaning the beep is disabled.
3984 @item sample_rate, r
3985 Specify the sample rate, default is 44100.
3988 Specify the duration of the generated audio stream.
3990 @item samples_per_frame
3991 Set the number of samples per output frame.
3993 The expression can contain the following constants:
3997 The (sequential) number of the output audio frame, starting from 0.
4000 The PTS (Presentation TimeStamp) of the output audio frame,
4001 expressed in @var{TB} units.
4004 The PTS of the output audio frame, expressed in seconds.
4007 The timebase of the output audio frames.
4010 Default is @code{1024}.
4013 @subsection Examples
4018 Generate a simple 440 Hz sine wave:
4024 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
4028 sine=frequency=220:beep_factor=4:duration=5
4032 Generate a 1 kHz sine wave following @code{1602,1601,1602,1601,1602} NTSC
4035 sine=1000:samples_per_frame='st(0,mod(n,5)); 1602-not(not(eq(ld(0),1)+eq(ld(0),3)))'
4039 @c man end AUDIO SOURCES
4041 @chapter Audio Sinks
4042 @c man begin AUDIO SINKS
4044 Below is a description of the currently available audio sinks.
4046 @section abuffersink
4048 Buffer audio frames, and make them available to the end of filter chain.
4050 This sink is mainly intended for programmatic use, in particular
4051 through the interface defined in @file{libavfilter/buffersink.h}
4052 or the options system.
4054 It accepts a pointer to an AVABufferSinkContext structure, which
4055 defines the incoming buffers' formats, to be passed as the opaque
4056 parameter to @code{avfilter_init_filter} for initialization.
4059 Null audio sink; do absolutely nothing with the input audio. It is
4060 mainly useful as a template and for use in analysis / debugging
4063 @c man end AUDIO SINKS
4065 @chapter Video Filters
4066 @c man begin VIDEO FILTERS
4068 When you configure your FFmpeg build, you can disable any of the
4069 existing filters using @code{--disable-filters}.
4070 The configure output will show the video filters included in your
4073 Below is a description of the currently available video filters.
4075 @section alphaextract
4077 Extract the alpha component from the input as a grayscale video. This
4078 is especially useful with the @var{alphamerge} filter.
4082 Add or replace the alpha component of the primary input with the
4083 grayscale value of a second input. This is intended for use with
4084 @var{alphaextract} to allow the transmission or storage of frame
4085 sequences that have alpha in a format that doesn't support an alpha
4088 For example, to reconstruct full frames from a normal YUV-encoded video
4089 and a separate video created with @var{alphaextract}, you might use:
4091 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
4094 Since this filter is designed for reconstruction, it operates on frame
4095 sequences without considering timestamps, and terminates when either
4096 input reaches end of stream. This will cause problems if your encoding
4097 pipeline drops frames. If you're trying to apply an image as an
4098 overlay to a video stream, consider the @var{overlay} filter instead.
4102 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
4103 and libavformat to work. On the other hand, it is limited to ASS (Advanced
4104 Substation Alpha) subtitles files.
4106 This filter accepts the following option in addition to the common options from
4107 the @ref{subtitles} filter:
4111 Set the shaping engine
4113 Available values are:
4116 The default libass shaping engine, which is the best available.
4118 Fast, font-agnostic shaper that can do only substitutions
4120 Slower shaper using OpenType for substitutions and positioning
4123 The default is @code{auto}.
4127 Apply an Adaptive Temporal Averaging Denoiser to the video input.
4129 The filter accepts the following options:
4133 Set threshold A for 1st plane. Default is 0.02.
4134 Valid range is 0 to 0.3.
4137 Set threshold B for 1st plane. Default is 0.04.
4138 Valid range is 0 to 5.
4141 Set threshold A for 2nd plane. Default is 0.02.
4142 Valid range is 0 to 0.3.
4145 Set threshold B for 2nd plane. Default is 0.04.
4146 Valid range is 0 to 5.
4149 Set threshold A for 3rd plane. Default is 0.02.
4150 Valid range is 0 to 0.3.
4153 Set threshold B for 3rd plane. Default is 0.04.
4154 Valid range is 0 to 5.
4156 Threshold A is designed to react on abrupt changes in the input signal and
4157 threshold B is designed to react on continuous changes in the input signal.
4160 Set number of frames filter will use for averaging. Default is 33. Must be odd
4161 number in range [5, 129].
4166 Compute the bounding box for the non-black pixels in the input frame
4169 This filter computes the bounding box containing all the pixels with a
4170 luminance value greater than the minimum allowed value.
4171 The parameters describing the bounding box are printed on the filter
4174 The filter accepts the following option:
4178 Set the minimal luminance value. Default is @code{16}.
4181 @section blackdetect
4183 Detect video intervals that are (almost) completely black. Can be
4184 useful to detect chapter transitions, commercials, or invalid
4185 recordings. Output lines contains the time for the start, end and
4186 duration of the detected black interval expressed in seconds.
4188 In order to display the output lines, you need to set the loglevel at
4189 least to the AV_LOG_INFO value.
4191 The filter accepts the following options:
4194 @item black_min_duration, d
4195 Set the minimum detected black duration expressed in seconds. It must
4196 be a non-negative floating point number.
4198 Default value is 2.0.
4200 @item picture_black_ratio_th, pic_th
4201 Set the threshold for considering a picture "black".
4202 Express the minimum value for the ratio:
4204 @var{nb_black_pixels} / @var{nb_pixels}
4207 for which a picture is considered black.
4208 Default value is 0.98.
4210 @item pixel_black_th, pix_th
4211 Set the threshold for considering a pixel "black".
4213 The threshold expresses the maximum pixel luminance value for which a
4214 pixel is considered "black". The provided value is scaled according to
4215 the following equation:
4217 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
4220 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
4221 the input video format, the range is [0-255] for YUV full-range
4222 formats and [16-235] for YUV non full-range formats.
4224 Default value is 0.10.
4227 The following example sets the maximum pixel threshold to the minimum
4228 value, and detects only black intervals of 2 or more seconds:
4230 blackdetect=d=2:pix_th=0.00
4235 Detect frames that are (almost) completely black. Can be useful to
4236 detect chapter transitions or commercials. Output lines consist of
4237 the frame number of the detected frame, the percentage of blackness,
4238 the position in the file if known or -1 and the timestamp in seconds.
4240 In order to display the output lines, you need to set the loglevel at
4241 least to the AV_LOG_INFO value.
4243 It accepts the following parameters:
4248 The percentage of the pixels that have to be below the threshold; it defaults to
4251 @item threshold, thresh
4252 The threshold below which a pixel value is considered black; it defaults to
4257 @section blend, tblend
4259 Blend two video frames into each other.
4261 The @code{blend} filter takes two input streams and outputs one
4262 stream, the first input is the "top" layer and second input is
4263 "bottom" layer. Output terminates when shortest input terminates.
4265 The @code{tblend} (time blend) filter takes two consecutive frames
4266 from one single stream, and outputs the result obtained by blending
4267 the new frame on top of the old frame.
4269 A description of the accepted options follows.
4277 Set blend mode for specific pixel component or all pixel components in case
4278 of @var{all_mode}. Default value is @code{normal}.
4280 Available values for component modes are:
4321 Set blend opacity for specific pixel component or all pixel components in case
4322 of @var{all_opacity}. Only used in combination with pixel component blend modes.
4329 Set blend expression for specific pixel component or all pixel components in case
4330 of @var{all_expr}. Note that related mode options will be ignored if those are set.
4332 The expressions can use the following variables:
4336 The sequential number of the filtered frame, starting from @code{0}.
4340 the coordinates of the current sample
4344 the width and height of currently filtered plane
4348 Width and height scale depending on the currently filtered plane. It is the
4349 ratio between the corresponding luma plane number of pixels and the current
4350 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4351 @code{0.5,0.5} for chroma planes.
4354 Time of the current frame, expressed in seconds.
4357 Value of pixel component at current location for first video frame (top layer).
4360 Value of pixel component at current location for second video frame (bottom layer).
4364 Force termination when the shortest input terminates. Default is
4365 @code{0}. This option is only defined for the @code{blend} filter.
4368 Continue applying the last bottom frame after the end of the stream. A value of
4369 @code{0} disable the filter after the last frame of the bottom layer is reached.
4370 Default is @code{1}. This option is only defined for the @code{blend} filter.
4373 @subsection Examples
4377 Apply transition from bottom layer to top layer in first 10 seconds:
4379 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
4383 Apply 1x1 checkerboard effect:
4385 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
4389 Apply uncover left effect:
4391 blend=all_expr='if(gte(N*SW+X,W),A,B)'
4395 Apply uncover down effect:
4397 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
4401 Apply uncover up-left effect:
4403 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
4407 Split diagonally video and shows top and bottom layer on each side:
4409 blend=all_expr=if(gt(X,Y*(W/H)),A,B)
4413 Display differences between the current and the previous frame:
4415 tblend=all_mode=difference128
4421 Deinterlace the input video ("bwdif" stands for "Bob Weaver
4422 Deinterlacing Filter").
4424 Motion adaptive deinterlacing based on yadif with the use of w3fdif and cubic
4425 interpolation algorithms.
4426 It accepts the following parameters:
4430 The interlacing mode to adopt. It accepts one of the following values:
4434 Output one frame for each frame.
4436 Output one frame for each field.
4439 The default value is @code{send_field}.
4442 The picture field parity assumed for the input interlaced video. It accepts one
4443 of the following values:
4447 Assume the top field is first.
4449 Assume the bottom field is first.
4451 Enable automatic detection of field parity.
4454 The default value is @code{auto}.
4455 If the interlacing is unknown or the decoder does not export this information,
4456 top field first will be assumed.
4459 Specify which frames to deinterlace. Accept one of the following
4464 Deinterlace all frames.
4466 Only deinterlace frames marked as interlaced.
4469 The default value is @code{all}.
4474 Apply a boxblur algorithm to the input video.
4476 It accepts the following parameters:
4480 @item luma_radius, lr
4481 @item luma_power, lp
4482 @item chroma_radius, cr
4483 @item chroma_power, cp
4484 @item alpha_radius, ar
4485 @item alpha_power, ap
4489 A description of the accepted options follows.
4492 @item luma_radius, lr
4493 @item chroma_radius, cr
4494 @item alpha_radius, ar
4495 Set an expression for the box radius in pixels used for blurring the
4496 corresponding input plane.
4498 The radius value must be a non-negative number, and must not be
4499 greater than the value of the expression @code{min(w,h)/2} for the
4500 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
4503 Default value for @option{luma_radius} is "2". If not specified,
4504 @option{chroma_radius} and @option{alpha_radius} default to the
4505 corresponding value set for @option{luma_radius}.
4507 The expressions can contain the following constants:
4511 The input width and height in pixels.
4515 The input chroma image width and height in pixels.
4519 The horizontal and vertical chroma subsample values. For example, for the
4520 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
4523 @item luma_power, lp
4524 @item chroma_power, cp
4525 @item alpha_power, ap
4526 Specify how many times the boxblur filter is applied to the
4527 corresponding plane.
4529 Default value for @option{luma_power} is 2. If not specified,
4530 @option{chroma_power} and @option{alpha_power} default to the
4531 corresponding value set for @option{luma_power}.
4533 A value of 0 will disable the effect.
4536 @subsection Examples
4540 Apply a boxblur filter with the luma, chroma, and alpha radii
4543 boxblur=luma_radius=2:luma_power=1
4548 Set the luma radius to 2, and alpha and chroma radius to 0:
4550 boxblur=2:1:cr=0:ar=0
4554 Set the luma and chroma radii to a fraction of the video dimension:
4556 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
4561 YUV colorspace color/chroma keying.
4563 The filter accepts the following options:
4567 The color which will be replaced with transparency.
4570 Similarity percentage with the key color.
4572 0.01 matches only the exact key color, while 1.0 matches everything.
4577 0.0 makes pixels either fully transparent, or not transparent at all.
4579 Higher values result in semi-transparent pixels, with a higher transparency
4580 the more similar the pixels color is to the key color.
4583 Signals that the color passed is already in YUV instead of RGB.
4585 Litteral colors like "green" or "red" don't make sense with this enabled anymore.
4586 This can be used to pass exact YUV values as hexadecimal numbers.
4589 @subsection Examples
4593 Make every green pixel in the input image transparent:
4595 ffmpeg -i input.png -vf chromakey=green out.png
4599 Overlay a greenscreen-video on top of a static black background.
4601 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
4607 Display CIE color diagram with pixels overlaid onto it.
4609 The filter acccepts the following options:
4624 @item uhdtv, rec2020
4637 Set what gamuts to draw.
4639 See @code{system} option for avaiable values.
4642 Set ciescope size, by default set to 512.
4645 Set intensity used to map input pixel values to CIE diagram.
4648 Set contrast used to draw tongue colors that are out of active color system gamut.
4651 Correct gamma displayed on scope, by default enabled.
4654 Show white point on CIE diagram, by default disabled.
4657 Set input gamma. Used only with XYZ input color space.
4662 Visualize information exported by some codecs.
4664 Some codecs can export information through frames using side-data or other
4665 means. For example, some MPEG based codecs export motion vectors through the
4666 @var{export_mvs} flag in the codec @option{flags2} option.
4668 The filter accepts the following option:
4672 Set motion vectors to visualize.
4674 Available flags for @var{mv} are:
4678 forward predicted MVs of P-frames
4680 forward predicted MVs of B-frames
4682 backward predicted MVs of B-frames
4686 Display quantization parameters using the chroma planes
4689 @subsection Examples
4693 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
4695 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
4699 @section colorbalance
4700 Modify intensity of primary colors (red, green and blue) of input frames.
4702 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
4703 regions for the red-cyan, green-magenta or blue-yellow balance.
4705 A positive adjustment value shifts the balance towards the primary color, a negative
4706 value towards the complementary color.
4708 The filter accepts the following options:
4714 Adjust red, green and blue shadows (darkest pixels).
4719 Adjust red, green and blue midtones (medium pixels).
4724 Adjust red, green and blue highlights (brightest pixels).
4726 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
4729 @subsection Examples
4733 Add red color cast to shadows:
4740 RGB colorspace color keying.
4742 The filter accepts the following options:
4746 The color which will be replaced with transparency.
4749 Similarity percentage with the key color.
4751 0.01 matches only the exact key color, while 1.0 matches everything.
4756 0.0 makes pixels either fully transparent, or not transparent at all.
4758 Higher values result in semi-transparent pixels, with a higher transparency
4759 the more similar the pixels color is to the key color.
4762 @subsection Examples
4766 Make every green pixel in the input image transparent:
4768 ffmpeg -i input.png -vf colorkey=green out.png
4772 Overlay a greenscreen-video on top of a static background image.
4774 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
4778 @section colorlevels
4780 Adjust video input frames using levels.
4782 The filter accepts the following options:
4789 Adjust red, green, blue and alpha input black point.
4790 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
4796 Adjust red, green, blue and alpha input white point.
4797 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
4799 Input levels are used to lighten highlights (bright tones), darken shadows
4800 (dark tones), change the balance of bright and dark tones.
4806 Adjust red, green, blue and alpha output black point.
4807 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
4813 Adjust red, green, blue and alpha output white point.
4814 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
4816 Output levels allows manual selection of a constrained output level range.
4819 @subsection Examples
4823 Make video output darker:
4825 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
4831 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
4835 Make video output lighter:
4837 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
4841 Increase brightness:
4843 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
4847 @section colorchannelmixer
4849 Adjust video input frames by re-mixing color channels.
4851 This filter modifies a color channel by adding the values associated to
4852 the other channels of the same pixels. For example if the value to
4853 modify is red, the output value will be:
4855 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
4858 The filter accepts the following options:
4865 Adjust contribution of input red, green, blue and alpha channels for output red channel.
4866 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
4872 Adjust contribution of input red, green, blue and alpha channels for output green channel.
4873 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
4879 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
4880 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
4886 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
4887 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
4889 Allowed ranges for options are @code{[-2.0, 2.0]}.
4892 @subsection Examples
4896 Convert source to grayscale:
4898 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
4901 Simulate sepia tones:
4903 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
4907 @section colormatrix
4909 Convert color matrix.
4911 The filter accepts the following options:
4916 Specify the source and destination color matrix. Both values must be
4919 The accepted values are:
4935 For example to convert from BT.601 to SMPTE-240M, use the command:
4937 colormatrix=bt601:smpte240m
4942 Convert colorspace, transfer characteristics or color primaries.
4944 The filter accepts the following options:
4948 Specify all color properties at once.
4950 The accepted values are:
4979 Specify output colorspace.
4981 The accepted values are:
4990 BT.470BG or BT.601-6 625
4993 SMPTE-170M or BT.601-6 525
4999 BT.2020 with non-constant luminance
5004 Specify output transfer characteristics.
5006 The accepted values are:
5012 Constant gamma of 2.2
5015 Constant gamma of 2.8
5018 SMPTE-170M, BT.601-6 625 or BT.601-6 525
5024 BT.2020 for 10-bits content
5027 BT.2020 for 12-bits content
5032 Specify output color primaries.
5034 The accepted values are:
5043 BT.470BG or BT.601-6 625
5046 SMPTE-170M or BT.601-6 525
5057 Specify output color range.
5059 The accepted values are:
5062 MPEG (restricted) range
5070 Specify output color format.
5072 The accepted values are:
5075 YUV 4:2:0 planar 8-bits
5078 YUV 4:2:0 planar 10-bits
5081 YUV 4:2:0 planar 12-bits
5084 YUV 4:2:2 planar 8-bits
5087 YUV 4:2:2 planar 10-bits
5090 YUV 4:2:2 planar 12-bits
5093 YUV 4:4:4 planar 8-bits
5096 YUV 4:4:4 planar 10-bits
5099 YUV 4:4:4 planar 12-bits
5104 Do a fast conversion, which skips gamma/primary correction. This will take
5105 significantly less CPU, but will be mathematically incorrect. To get output
5106 compatible with that produced by the colormatrix filter, use fast=1.
5109 The filter converts the transfer characteristics, color space and color
5110 primaries to the specified user values. The output value, if not specified,
5111 is set to a default value based on the "all" property. If that property is
5112 also not specified, the filter will log an error. The output color range and
5113 format default to the same value as the input color range and format. The
5114 input transfer characteristics, color space, color primaries and color range
5115 should be set on the input data. If any of these are missing, the filter will
5116 log an error and no conversion will take place.
5118 For example to convert the input to SMPTE-240M, use the command:
5120 colorspace=smpte240m
5123 @section convolution
5125 Apply convolution 3x3 or 5x5 filter.
5127 The filter accepts the following options:
5134 Set matrix for each plane.
5135 Matrix is sequence of 9 or 25 signed integers.
5141 Set multiplier for calculated value for each plane.
5147 Set bias for each plane. This value is added to the result of the multiplication.
5148 Useful for making the overall image brighter or darker. Default is 0.0.
5151 @subsection Examples
5157 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"
5163 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"
5169 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"
5175 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"
5181 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"
5187 Copy the input source unchanged to the output. This is mainly useful for
5192 Video filtering on GPU using Apple's CoreImage API on OSX.
5194 Hardware acceleration is based on an OpenGL context. Usually, this means it is
5195 processed by video hardware. However, software-based OpenGL implementations
5196 exist which means there is no guarantee for hardware processing. It depends on
5199 There are many filters and image generators provided by Apple that come with a
5200 large variety of options. The filter has to be referenced by its name along
5203 The coreimage filter accepts the following options:
5206 List all available filters and generators along with all their respective
5207 options as well as possible minimum and maximum values along with the default
5214 Specify all filters by their respective name and options.
5215 Use @var{list_filters} to determine all valid filter names and options.
5216 Numerical options are specified by a float value and are automatically clamped
5217 to their respective value range. Vector and color options have to be specified
5218 by a list of space separated float values. Character escaping has to be done.
5219 A special option name @code{default} is available to use default options for a
5222 It is required to specify either @code{default} or at least one of the filter options.
5223 All omitted options are used with their default values.
5224 The syntax of the filter string is as follows:
5226 filter=<NAME>@@<OPTION>=<VALUE>[@@<OPTION>=<VALUE>][@@...][#<NAME>@@<OPTION>=<VALUE>[@@<OPTION>=<VALUE>][@@...]][#...]
5230 Specify a rectangle where the output of the filter chain is copied into the
5231 input image. It is given by a list of space separated float values:
5233 output_rect=x\ y\ width\ height
5235 If not given, the output rectangle equals the dimensions of the input image.
5236 The output rectangle is automatically cropped at the borders of the input
5237 image. Negative values are valid for each component.
5239 output_rect=25\ 25\ 100\ 100
5243 Several filters can be chained for successive processing without GPU-HOST
5244 transfers allowing for fast processing of complex filter chains.
5245 Currently, only filters with zero (generators) or exactly one (filters) input
5246 image and one output image are supported. Also, transition filters are not yet
5249 Some filters generate output images with additional padding depending on the
5250 respective filter kernel. The padding is automatically removed to ensure the
5251 filter output has the same size as the input image.
5253 For image generators, the size of the output image is determined by the
5254 previous output image of the filter chain or the input image of the whole
5255 filterchain, respectively. The generators do not use the pixel information of
5256 this image to generate their output. However, the generated output is
5257 blended onto this image, resulting in partial or complete coverage of the
5260 The @ref{coreimagesrc} video source can be used for generating input images
5261 which are directly fed into the filter chain. By using it, providing input
5262 images by another video source or an input video is not required.
5264 @subsection Examples
5269 List all filters available:
5271 coreimage=list_filters=true
5275 Use the CIBoxBlur filter with default options to blur an image:
5277 coreimage=filter=CIBoxBlur@@default
5281 Use a filter chain with CISepiaTone at default values and CIVignetteEffect with
5282 its center at 100x100 and a radius of 50 pixels:
5284 coreimage=filter=CIBoxBlur@@default#CIVignetteEffect@@inputCenter=100\ 100@@inputRadius=50
5288 Use nullsrc and CIQRCodeGenerator to create a QR code for the FFmpeg homepage,
5289 given as complete and escaped command-line for Apple's standard bash shell:
5291 ffmpeg -f lavfi -i nullsrc=s=100x100,coreimage=filter=CIQRCodeGenerator@@inputMessage=https\\\\\://FFmpeg.org/@@inputCorrectionLevel=H -frames:v 1 QRCode.png
5297 Crop the input video to given dimensions.
5299 It accepts the following parameters:
5303 The width of the output video. It defaults to @code{iw}.
5304 This expression is evaluated only once during the filter
5305 configuration, or when the @samp{w} or @samp{out_w} command is sent.
5308 The height of the output video. It defaults to @code{ih}.
5309 This expression is evaluated only once during the filter
5310 configuration, or when the @samp{h} or @samp{out_h} command is sent.
5313 The horizontal position, in the input video, of the left edge of the output
5314 video. It defaults to @code{(in_w-out_w)/2}.
5315 This expression is evaluated per-frame.
5318 The vertical position, in the input video, of the top edge of the output video.
5319 It defaults to @code{(in_h-out_h)/2}.
5320 This expression is evaluated per-frame.
5323 If set to 1 will force the output display aspect ratio
5324 to be the same of the input, by changing the output sample aspect
5325 ratio. It defaults to 0.
5328 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
5329 expressions containing the following constants:
5334 The computed values for @var{x} and @var{y}. They are evaluated for
5339 The input width and height.
5343 These are the same as @var{in_w} and @var{in_h}.
5347 The output (cropped) width and height.
5351 These are the same as @var{out_w} and @var{out_h}.
5354 same as @var{iw} / @var{ih}
5357 input sample aspect ratio
5360 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
5364 horizontal and vertical chroma subsample values. For example for the
5365 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5368 The number of the input frame, starting from 0.
5371 the position in the file of the input frame, NAN if unknown
5374 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
5378 The expression for @var{out_w} may depend on the value of @var{out_h},
5379 and the expression for @var{out_h} may depend on @var{out_w}, but they
5380 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
5381 evaluated after @var{out_w} and @var{out_h}.
5383 The @var{x} and @var{y} parameters specify the expressions for the
5384 position of the top-left corner of the output (non-cropped) area. They
5385 are evaluated for each frame. If the evaluated value is not valid, it
5386 is approximated to the nearest valid value.
5388 The expression for @var{x} may depend on @var{y}, and the expression
5389 for @var{y} may depend on @var{x}.
5391 @subsection Examples
5395 Crop area with size 100x100 at position (12,34).
5400 Using named options, the example above becomes:
5402 crop=w=100:h=100:x=12:y=34
5406 Crop the central input area with size 100x100:
5412 Crop the central input area with size 2/3 of the input video:
5414 crop=2/3*in_w:2/3*in_h
5418 Crop the input video central square:
5425 Delimit the rectangle with the top-left corner placed at position
5426 100:100 and the right-bottom corner corresponding to the right-bottom
5427 corner of the input image.
5429 crop=in_w-100:in_h-100:100:100
5433 Crop 10 pixels from the left and right borders, and 20 pixels from
5434 the top and bottom borders
5436 crop=in_w-2*10:in_h-2*20
5440 Keep only the bottom right quarter of the input image:
5442 crop=in_w/2:in_h/2:in_w/2:in_h/2
5446 Crop height for getting Greek harmony:
5448 crop=in_w:1/PHI*in_w
5452 Apply trembling effect:
5454 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)
5458 Apply erratic camera effect depending on timestamp:
5460 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)"
5464 Set x depending on the value of y:
5466 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
5470 @subsection Commands
5472 This filter supports the following commands:
5478 Set width/height of the output video and the horizontal/vertical position
5480 The command accepts the same syntax of the corresponding option.
5482 If the specified expression is not valid, it is kept at its current
5488 Auto-detect the crop size.
5490 It calculates the necessary cropping parameters and prints the
5491 recommended parameters via the logging system. The detected dimensions
5492 correspond to the non-black area of the input video.
5494 It accepts the following parameters:
5499 Set higher black value threshold, which can be optionally specified
5500 from nothing (0) to everything (255 for 8bit based formats). An intensity
5501 value greater to the set value is considered non-black. It defaults to 24.
5502 You can also specify a value between 0.0 and 1.0 which will be scaled depending
5503 on the bitdepth of the pixel format.
5506 The value which the width/height should be divisible by. It defaults to
5507 16. The offset is automatically adjusted to center the video. Use 2 to
5508 get only even dimensions (needed for 4:2:2 video). 16 is best when
5509 encoding to most video codecs.
5511 @item reset_count, reset
5512 Set the counter that determines after how many frames cropdetect will
5513 reset the previously detected largest video area and start over to
5514 detect the current optimal crop area. Default value is 0.
5516 This can be useful when channel logos distort the video area. 0
5517 indicates 'never reset', and returns the largest area encountered during
5524 Apply color adjustments using curves.
5526 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
5527 component (red, green and blue) has its values defined by @var{N} key points
5528 tied from each other using a smooth curve. The x-axis represents the pixel
5529 values from the input frame, and the y-axis the new pixel values to be set for
5532 By default, a component curve is defined by the two points @var{(0;0)} and
5533 @var{(1;1)}. This creates a straight line where each original pixel value is
5534 "adjusted" to its own value, which means no change to the image.
5536 The filter allows you to redefine these two points and add some more. A new
5537 curve (using a natural cubic spline interpolation) will be define to pass
5538 smoothly through all these new coordinates. The new defined points needs to be
5539 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
5540 be in the @var{[0;1]} interval. If the computed curves happened to go outside
5541 the vector spaces, the values will be clipped accordingly.
5543 If there is no key point defined in @code{x=0}, the filter will automatically
5544 insert a @var{(0;0)} point. In the same way, if there is no key point defined
5545 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
5547 The filter accepts the following options:
5551 Select one of the available color presets. This option can be used in addition
5552 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
5553 options takes priority on the preset values.
5554 Available presets are:
5557 @item color_negative
5560 @item increase_contrast
5562 @item linear_contrast
5563 @item medium_contrast
5565 @item strong_contrast
5568 Default is @code{none}.
5570 Set the master key points. These points will define a second pass mapping. It
5571 is sometimes called a "luminance" or "value" mapping. It can be used with
5572 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
5573 post-processing LUT.
5575 Set the key points for the red component.
5577 Set the key points for the green component.
5579 Set the key points for the blue component.
5581 Set the key points for all components (not including master).
5582 Can be used in addition to the other key points component
5583 options. In this case, the unset component(s) will fallback on this
5584 @option{all} setting.
5586 Specify a Photoshop curves file (@code{.acv}) to import the settings from.
5589 To avoid some filtergraph syntax conflicts, each key points list need to be
5590 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
5592 @subsection Examples
5596 Increase slightly the middle level of blue:
5598 curves=blue='0.5/0.58'
5604 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
5606 Here we obtain the following coordinates for each components:
5609 @code{(0;0.11) (0.42;0.51) (1;0.95)}
5611 @code{(0;0) (0.50;0.48) (1;1)}
5613 @code{(0;0.22) (0.49;0.44) (1;0.80)}
5617 The previous example can also be achieved with the associated built-in preset:
5619 curves=preset=vintage
5629 Use a Photoshop preset and redefine the points of the green component:
5631 curves=psfile='MyCurvesPresets/purple.acv':green='0.45/0.53'
5637 Video data analysis filter.
5639 This filter shows hexadecimal pixel values of part of video.
5641 The filter accepts the following options:
5645 Set output video size.
5648 Set x offset from where to pick pixels.
5651 Set y offset from where to pick pixels.
5654 Set scope mode, can be one of the following:
5657 Draw hexadecimal pixel values with white color on black background.
5660 Draw hexadecimal pixel values with input video pixel color on black
5664 Draw hexadecimal pixel values on color background picked from input video,
5665 the text color is picked in such way so its always visible.
5669 Draw rows and columns numbers on left and top of video.
5674 Denoise frames using 2D DCT (frequency domain filtering).
5676 This filter is not designed for real time.
5678 The filter accepts the following options:
5682 Set the noise sigma constant.
5684 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
5685 coefficient (absolute value) below this threshold with be dropped.
5687 If you need a more advanced filtering, see @option{expr}.
5689 Default is @code{0}.
5692 Set number overlapping pixels for each block. Since the filter can be slow, you
5693 may want to reduce this value, at the cost of a less effective filter and the
5694 risk of various artefacts.
5696 If the overlapping value doesn't permit processing the whole input width or
5697 height, a warning will be displayed and according borders won't be denoised.
5699 Default value is @var{blocksize}-1, which is the best possible setting.
5702 Set the coefficient factor expression.
5704 For each coefficient of a DCT block, this expression will be evaluated as a
5705 multiplier value for the coefficient.
5707 If this is option is set, the @option{sigma} option will be ignored.
5709 The absolute value of the coefficient can be accessed through the @var{c}
5713 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
5714 @var{blocksize}, which is the width and height of the processed blocks.
5716 The default value is @var{3} (8x8) and can be raised to @var{4} for a
5717 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
5718 on the speed processing. Also, a larger block size does not necessarily means a
5722 @subsection Examples
5724 Apply a denoise with a @option{sigma} of @code{4.5}:
5729 The same operation can be achieved using the expression system:
5731 dctdnoiz=e='gte(c, 4.5*3)'
5734 Violent denoise using a block size of @code{16x16}:
5741 Remove banding artifacts from input video.
5742 It works by replacing banded pixels with average value of referenced pixels.
5744 The filter accepts the following options:
5751 Set banding detection threshold for each plane. Default is 0.02.
5752 Valid range is 0.00003 to 0.5.
5753 If difference between current pixel and reference pixel is less than threshold,
5754 it will be considered as banded.
5757 Banding detection range in pixels. Default is 16. If positive, random number
5758 in range 0 to set value will be used. If negative, exact absolute value
5760 The range defines square of four pixels around current pixel.
5763 Set direction in radians from which four pixel will be compared. If positive,
5764 random direction from 0 to set direction will be picked. If negative, exact of
5765 absolute value will be picked. For example direction 0, -PI or -2*PI radians
5766 will pick only pixels on same row and -PI/2 will pick only pixels on same
5770 If enabled, current pixel is compared with average value of all four
5771 surrounding pixels. The default is enabled. If disabled current pixel is
5772 compared with all four surrounding pixels. The pixel is considered banded
5773 if only all four differences with surrounding pixels are less than threshold.
5779 Drop duplicated frames at regular intervals.
5781 The filter accepts the following options:
5785 Set the number of frames from which one will be dropped. Setting this to
5786 @var{N} means one frame in every batch of @var{N} frames will be dropped.
5787 Default is @code{5}.
5790 Set the threshold for duplicate detection. If the difference metric for a frame
5791 is less than or equal to this value, then it is declared as duplicate. Default
5795 Set scene change threshold. Default is @code{15}.
5799 Set the size of the x and y-axis blocks used during metric calculations.
5800 Larger blocks give better noise suppression, but also give worse detection of
5801 small movements. Must be a power of two. Default is @code{32}.
5804 Mark main input as a pre-processed input and activate clean source input
5805 stream. This allows the input to be pre-processed with various filters to help
5806 the metrics calculation while keeping the frame selection lossless. When set to
5807 @code{1}, the first stream is for the pre-processed input, and the second
5808 stream is the clean source from where the kept frames are chosen. Default is
5812 Set whether or not chroma is considered in the metric calculations. Default is
5818 Apply deflate effect to the video.
5820 This filter replaces the pixel by the local(3x3) average by taking into account
5821 only values lower than the pixel.
5823 It accepts the following options:
5830 Limit the maximum change for each plane, default is 65535.
5831 If 0, plane will remain unchanged.
5836 Remove judder produced by partially interlaced telecined content.
5838 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
5839 source was partially telecined content then the output of @code{pullup,dejudder}
5840 will have a variable frame rate. May change the recorded frame rate of the
5841 container. Aside from that change, this filter will not affect constant frame
5844 The option available in this filter is:
5848 Specify the length of the window over which the judder repeats.
5850 Accepts any integer greater than 1. Useful values are:
5854 If the original was telecined from 24 to 30 fps (Film to NTSC).
5857 If the original was telecined from 25 to 30 fps (PAL to NTSC).
5860 If a mixture of the two.
5863 The default is @samp{4}.
5868 Suppress a TV station logo by a simple interpolation of the surrounding
5869 pixels. Just set a rectangle covering the logo and watch it disappear
5870 (and sometimes something even uglier appear - your mileage may vary).
5872 It accepts the following parameters:
5877 Specify the top left corner coordinates of the logo. They must be
5882 Specify the width and height of the logo to clear. They must be
5886 Specify the thickness of the fuzzy edge of the rectangle (added to
5887 @var{w} and @var{h}). The default value is 1. This option is
5888 deprecated, setting higher values should no longer be necessary and
5892 When set to 1, a green rectangle is drawn on the screen to simplify
5893 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
5894 The default value is 0.
5896 The rectangle is drawn on the outermost pixels which will be (partly)
5897 replaced with interpolated values. The values of the next pixels
5898 immediately outside this rectangle in each direction will be used to
5899 compute the interpolated pixel values inside the rectangle.
5903 @subsection Examples
5907 Set a rectangle covering the area with top left corner coordinates 0,0
5908 and size 100x77, and a band of size 10:
5910 delogo=x=0:y=0:w=100:h=77:band=10
5917 Attempt to fix small changes in horizontal and/or vertical shift. This
5918 filter helps remove camera shake from hand-holding a camera, bumping a
5919 tripod, moving on a vehicle, etc.
5921 The filter accepts the following options:
5929 Specify a rectangular area where to limit the search for motion
5931 If desired the search for motion vectors can be limited to a
5932 rectangular area of the frame defined by its top left corner, width
5933 and height. These parameters have the same meaning as the drawbox
5934 filter which can be used to visualise the position of the bounding
5937 This is useful when simultaneous movement of subjects within the frame
5938 might be confused for camera motion by the motion vector search.
5940 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
5941 then the full frame is used. This allows later options to be set
5942 without specifying the bounding box for the motion vector search.
5944 Default - search the whole frame.
5948 Specify the maximum extent of movement in x and y directions in the
5949 range 0-64 pixels. Default 16.
5952 Specify how to generate pixels to fill blanks at the edge of the
5953 frame. Available values are:
5956 Fill zeroes at blank locations
5958 Original image at blank locations
5960 Extruded edge value at blank locations
5962 Mirrored edge at blank locations
5964 Default value is @samp{mirror}.
5967 Specify the blocksize to use for motion search. Range 4-128 pixels,
5971 Specify the contrast threshold for blocks. Only blocks with more than
5972 the specified contrast (difference between darkest and lightest
5973 pixels) will be considered. Range 1-255, default 125.
5976 Specify the search strategy. Available values are:
5979 Set exhaustive search
5981 Set less exhaustive search.
5983 Default value is @samp{exhaustive}.
5986 If set then a detailed log of the motion search is written to the
5990 If set to 1, specify using OpenCL capabilities, only available if
5991 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
5997 Apply an exact inverse of the telecine operation. It requires a predefined
5998 pattern specified using the pattern option which must be the same as that passed
5999 to the telecine filter.
6001 This filter accepts the following options:
6010 The default value is @code{top}.
6014 A string of numbers representing the pulldown pattern you wish to apply.
6015 The default value is @code{23}.
6018 A number representing position of the first frame with respect to the telecine
6019 pattern. This is to be used if the stream is cut. The default value is @code{0}.
6024 Apply dilation effect to the video.
6026 This filter replaces the pixel by the local(3x3) maximum.
6028 It accepts the following options:
6035 Limit the maximum change for each plane, default is 65535.
6036 If 0, plane will remain unchanged.
6039 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
6042 Flags to local 3x3 coordinates maps like this:
6051 Displace pixels as indicated by second and third input stream.
6053 It takes three input streams and outputs one stream, the first input is the
6054 source, and second and third input are displacement maps.
6056 The second input specifies how much to displace pixels along the
6057 x-axis, while the third input specifies how much to displace pixels
6059 If one of displacement map streams terminates, last frame from that
6060 displacement map will be used.
6062 Note that once generated, displacements maps can be reused over and over again.
6064 A description of the accepted options follows.
6068 Set displace behavior for pixels that are out of range.
6070 Available values are:
6073 Missing pixels are replaced by black pixels.
6076 Adjacent pixels will spread out to replace missing pixels.
6079 Out of range pixels are wrapped so they point to pixels of other side.
6081 Default is @samp{smear}.
6085 @subsection Examples
6089 Add ripple effect to rgb input of video size hd720:
6091 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
6095 Add wave effect to rgb input of video size hd720:
6097 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
6103 Draw a colored box on the input image.
6105 It accepts the following parameters:
6110 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
6114 The expressions which specify the width and height of the box; if 0 they are interpreted as
6115 the input width and height. It defaults to 0.
6118 Specify the color of the box to write. For the general syntax of this option,
6119 check the "Color" section in the ffmpeg-utils manual. If the special
6120 value @code{invert} is used, the box edge color is the same as the
6121 video with inverted luma.
6124 The expression which sets the thickness of the box edge. Default value is @code{3}.
6126 See below for the list of accepted constants.
6129 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
6130 following constants:
6134 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
6138 horizontal and vertical chroma subsample values. For example for the
6139 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6143 The input width and height.
6146 The input sample aspect ratio.
6150 The x and y offset coordinates where the box is drawn.
6154 The width and height of the drawn box.
6157 The thickness of the drawn box.
6159 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
6160 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
6164 @subsection Examples
6168 Draw a black box around the edge of the input image:
6174 Draw a box with color red and an opacity of 50%:
6176 drawbox=10:20:200:60:red@@0.5
6179 The previous example can be specified as:
6181 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
6185 Fill the box with pink color:
6187 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
6191 Draw a 2-pixel red 2.40:1 mask:
6193 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
6197 @section drawgraph, adrawgraph
6199 Draw a graph using input video or audio metadata.
6201 It accepts the following parameters:
6205 Set 1st frame metadata key from which metadata values will be used to draw a graph.
6208 Set 1st foreground color expression.
6211 Set 2nd frame metadata key from which metadata values will be used to draw a graph.
6214 Set 2nd foreground color expression.
6217 Set 3rd frame metadata key from which metadata values will be used to draw a graph.
6220 Set 3rd foreground color expression.
6223 Set 4th frame metadata key from which metadata values will be used to draw a graph.
6226 Set 4th foreground color expression.
6229 Set minimal value of metadata value.
6232 Set maximal value of metadata value.
6235 Set graph background color. Default is white.
6240 Available values for mode is:
6247 Default is @code{line}.
6252 Available values for slide is:
6255 Draw new frame when right border is reached.
6258 Replace old columns with new ones.
6261 Scroll from right to left.
6264 Scroll from left to right.
6267 Default is @code{frame}.
6270 Set size of graph video. For the syntax of this option, check the
6271 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
6272 The default value is @code{900x256}.
6274 The foreground color expressions can use the following variables:
6277 Minimal value of metadata value.
6280 Maximal value of metadata value.
6283 Current metadata key value.
6286 The color is defined as 0xAABBGGRR.
6289 Example using metadata from @ref{signalstats} filter:
6291 signalstats,drawgraph=lavfi.signalstats.YAVG:min=0:max=255
6294 Example using metadata from @ref{ebur128} filter:
6296 ebur128=metadata=1,adrawgraph=lavfi.r128.M:min=-120:max=5
6301 Draw a grid on the input image.
6303 It accepts the following parameters:
6308 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
6312 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
6313 input width and height, respectively, minus @code{thickness}, so image gets
6314 framed. Default to 0.
6317 Specify the color of the grid. For the general syntax of this option,
6318 check the "Color" section in the ffmpeg-utils manual. If the special
6319 value @code{invert} is used, the grid color is the same as the
6320 video with inverted luma.
6323 The expression which sets the thickness of the grid line. Default value is @code{1}.
6325 See below for the list of accepted constants.
6328 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
6329 following constants:
6333 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
6337 horizontal and vertical chroma subsample values. For example for the
6338 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6342 The input grid cell width and height.
6345 The input sample aspect ratio.
6349 The x and y coordinates of some point of grid intersection (meant to configure offset).
6353 The width and height of the drawn cell.
6356 The thickness of the drawn cell.
6358 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
6359 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
6363 @subsection Examples
6367 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
6369 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
6373 Draw a white 3x3 grid with an opacity of 50%:
6375 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
6382 Draw a text string or text from a specified file on top of a video, using the
6383 libfreetype library.
6385 To enable compilation of this filter, you need to configure FFmpeg with
6386 @code{--enable-libfreetype}.
6387 To enable default font fallback and the @var{font} option you need to
6388 configure FFmpeg with @code{--enable-libfontconfig}.
6389 To enable the @var{text_shaping} option, you need to configure FFmpeg with
6390 @code{--enable-libfribidi}.
6394 It accepts the following parameters:
6399 Used to draw a box around text using the background color.
6400 The value must be either 1 (enable) or 0 (disable).
6401 The default value of @var{box} is 0.
6404 Set the width of the border to be drawn around the box using @var{boxcolor}.
6405 The default value of @var{boxborderw} is 0.
6408 The color to be used for drawing box around text. For the syntax of this
6409 option, check the "Color" section in the ffmpeg-utils manual.
6411 The default value of @var{boxcolor} is "white".
6414 Set the width of the border to be drawn around the text using @var{bordercolor}.
6415 The default value of @var{borderw} is 0.
6418 Set the color to be used for drawing border around text. For the syntax of this
6419 option, check the "Color" section in the ffmpeg-utils manual.
6421 The default value of @var{bordercolor} is "black".
6424 Select how the @var{text} is expanded. Can be either @code{none},
6425 @code{strftime} (deprecated) or
6426 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
6430 If true, check and fix text coords to avoid clipping.
6433 The color to be used for drawing fonts. For the syntax of this option, check
6434 the "Color" section in the ffmpeg-utils manual.
6436 The default value of @var{fontcolor} is "black".
6438 @item fontcolor_expr
6439 String which is expanded the same way as @var{text} to obtain dynamic
6440 @var{fontcolor} value. By default this option has empty value and is not
6441 processed. When this option is set, it overrides @var{fontcolor} option.
6444 The font family to be used for drawing text. By default Sans.
6447 The font file to be used for drawing text. The path must be included.
6448 This parameter is mandatory if the fontconfig support is disabled.
6451 This option does not exist, please see the timeline system
6454 Draw the text applying alpha blending. The value can
6455 be either a number between 0.0 and 1.0
6456 The expression accepts the same variables @var{x, y} do.
6457 The default value is 1.
6458 Please see fontcolor_expr
6461 The font size to be used for drawing text.
6462 The default value of @var{fontsize} is 16.
6465 If set to 1, attempt to shape the text (for example, reverse the order of
6466 right-to-left text and join Arabic characters) before drawing it.
6467 Otherwise, just draw the text exactly as given.
6468 By default 1 (if supported).
6471 The flags to be used for loading the fonts.
6473 The flags map the corresponding flags supported by libfreetype, and are
6474 a combination of the following values:
6481 @item vertical_layout
6482 @item force_autohint
6485 @item ignore_global_advance_width
6487 @item ignore_transform
6493 Default value is "default".
6495 For more information consult the documentation for the FT_LOAD_*
6499 The color to be used for drawing a shadow behind the drawn text. For the
6500 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
6502 The default value of @var{shadowcolor} is "black".
6506 The x and y offsets for the text shadow position with respect to the
6507 position of the text. They can be either positive or negative
6508 values. The default value for both is "0".
6511 The starting frame number for the n/frame_num variable. The default value
6515 The size in number of spaces to use for rendering the tab.
6519 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
6520 format. It can be used with or without text parameter. @var{timecode_rate}
6521 option must be specified.
6523 @item timecode_rate, rate, r
6524 Set the timecode frame rate (timecode only).
6527 The text string to be drawn. The text must be a sequence of UTF-8
6529 This parameter is mandatory if no file is specified with the parameter
6533 A text file containing text to be drawn. The text must be a sequence
6534 of UTF-8 encoded characters.
6536 This parameter is mandatory if no text string is specified with the
6537 parameter @var{text}.
6539 If both @var{text} and @var{textfile} are specified, an error is thrown.
6542 If set to 1, the @var{textfile} will be reloaded before each frame.
6543 Be sure to update it atomically, or it may be read partially, or even fail.
6547 The expressions which specify the offsets where text will be drawn
6548 within the video frame. They are relative to the top/left border of the
6551 The default value of @var{x} and @var{y} is "0".
6553 See below for the list of accepted constants and functions.
6556 The parameters for @var{x} and @var{y} are expressions containing the
6557 following constants and functions:
6561 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
6565 horizontal and vertical chroma subsample values. For example for the
6566 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6569 the height of each text line
6577 @item max_glyph_a, ascent
6578 the maximum distance from the baseline to the highest/upper grid
6579 coordinate used to place a glyph outline point, for all the rendered
6581 It is a positive value, due to the grid's orientation with the Y axis
6584 @item max_glyph_d, descent
6585 the maximum distance from the baseline to the lowest grid coordinate
6586 used to place a glyph outline point, for all the rendered glyphs.
6587 This is a negative value, due to the grid's orientation, with the Y axis
6591 maximum glyph height, that is the maximum height for all the glyphs
6592 contained in the rendered text, it is equivalent to @var{ascent} -
6596 maximum glyph width, that is the maximum width for all the glyphs
6597 contained in the rendered text
6600 the number of input frame, starting from 0
6602 @item rand(min, max)
6603 return a random number included between @var{min} and @var{max}
6606 The input sample aspect ratio.
6609 timestamp expressed in seconds, NAN if the input timestamp is unknown
6612 the height of the rendered text
6615 the width of the rendered text
6619 the x and y offset coordinates where the text is drawn.
6621 These parameters allow the @var{x} and @var{y} expressions to refer
6622 each other, so you can for example specify @code{y=x/dar}.
6625 @anchor{drawtext_expansion}
6626 @subsection Text expansion
6628 If @option{expansion} is set to @code{strftime},
6629 the filter recognizes strftime() sequences in the provided text and
6630 expands them accordingly. Check the documentation of strftime(). This
6631 feature is deprecated.
6633 If @option{expansion} is set to @code{none}, the text is printed verbatim.
6635 If @option{expansion} is set to @code{normal} (which is the default),
6636 the following expansion mechanism is used.
6638 The backslash character @samp{\}, followed by any character, always expands to
6639 the second character.
6641 Sequence of the form @code{%@{...@}} are expanded. The text between the
6642 braces is a function name, possibly followed by arguments separated by ':'.
6643 If the arguments contain special characters or delimiters (':' or '@}'),
6644 they should be escaped.
6646 Note that they probably must also be escaped as the value for the
6647 @option{text} option in the filter argument string and as the filter
6648 argument in the filtergraph description, and possibly also for the shell,
6649 that makes up to four levels of escaping; using a text file avoids these
6652 The following functions are available:
6657 The expression evaluation result.
6659 It must take one argument specifying the expression to be evaluated,
6660 which accepts the same constants and functions as the @var{x} and
6661 @var{y} values. Note that not all constants should be used, for
6662 example the text size is not known when evaluating the expression, so
6663 the constants @var{text_w} and @var{text_h} will have an undefined
6666 @item expr_int_format, eif
6667 Evaluate the expression's value and output as formatted integer.
6669 The first argument is the expression to be evaluated, just as for the @var{expr} function.
6670 The second argument specifies the output format. Allowed values are @samp{x},
6671 @samp{X}, @samp{d} and @samp{u}. They are treated exactly as in the
6672 @code{printf} function.
6673 The third parameter is optional and sets the number of positions taken by the output.
6674 It can be used to add padding with zeros from the left.
6677 The time at which the filter is running, expressed in UTC.
6678 It can accept an argument: a strftime() format string.
6681 The time at which the filter is running, expressed in the local time zone.
6682 It can accept an argument: a strftime() format string.
6685 Frame metadata. Takes one or two arguments.
6687 The first argument is mandatory and specifies the metadata key.
6689 The second argument is optional and specifies a default value, used when the
6690 metadata key is not found or empty.
6693 The frame number, starting from 0.
6696 A 1 character description of the current picture type.
6699 The timestamp of the current frame.
6700 It can take up to three arguments.
6702 The first argument is the format of the timestamp; it defaults to @code{flt}
6703 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
6704 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
6705 @code{gmtime} stands for the timestamp of the frame formatted as UTC time;
6706 @code{localtime} stands for the timestamp of the frame formatted as
6707 local time zone time.
6709 The second argument is an offset added to the timestamp.
6711 If the format is set to @code{localtime} or @code{gmtime},
6712 a third argument may be supplied: a strftime() format string.
6713 By default, @var{YYYY-MM-DD HH:MM:SS} format will be used.
6716 @subsection Examples
6720 Draw "Test Text" with font FreeSerif, using the default values for the
6721 optional parameters.
6724 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
6728 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
6729 and y=50 (counting from the top-left corner of the screen), text is
6730 yellow with a red box around it. Both the text and the box have an
6734 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
6735 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
6738 Note that the double quotes are not necessary if spaces are not used
6739 within the parameter list.
6742 Show the text at the center of the video frame:
6744 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h)/2"
6748 Show the text at a random position, switching to a new position every 30 seconds:
6750 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)"
6754 Show a text line sliding from right to left in the last row of the video
6755 frame. The file @file{LONG_LINE} is assumed to contain a single line
6758 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
6762 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
6764 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
6768 Draw a single green letter "g", at the center of the input video.
6769 The glyph baseline is placed at half screen height.
6771 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
6775 Show text for 1 second every 3 seconds:
6777 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
6781 Use fontconfig to set the font. Note that the colons need to be escaped.
6783 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
6787 Print the date of a real-time encoding (see strftime(3)):
6789 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
6793 Show text fading in and out (appearing/disappearing):
6796 DS=1.0 # display start
6797 DE=10.0 # display end
6798 FID=1.5 # fade in duration
6799 FOD=5 # fade out duration
6800 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 @}"
6805 For more information about libfreetype, check:
6806 @url{http://www.freetype.org/}.
6808 For more information about fontconfig, check:
6809 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
6811 For more information about libfribidi, check:
6812 @url{http://fribidi.org/}.
6816 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
6818 The filter accepts the following options:
6823 Set low and high threshold values used by the Canny thresholding
6826 The high threshold selects the "strong" edge pixels, which are then
6827 connected through 8-connectivity with the "weak" edge pixels selected
6828 by the low threshold.
6830 @var{low} and @var{high} threshold values must be chosen in the range
6831 [0,1], and @var{low} should be lesser or equal to @var{high}.
6833 Default value for @var{low} is @code{20/255}, and default value for @var{high}
6837 Define the drawing mode.
6841 Draw white/gray wires on black background.
6844 Mix the colors to create a paint/cartoon effect.
6847 Default value is @var{wires}.
6850 @subsection Examples
6854 Standard edge detection with custom values for the hysteresis thresholding:
6856 edgedetect=low=0.1:high=0.4
6860 Painting effect without thresholding:
6862 edgedetect=mode=colormix:high=0
6867 Set brightness, contrast, saturation and approximate gamma adjustment.
6869 The filter accepts the following options:
6873 Set the contrast expression. The value must be a float value in range
6874 @code{-2.0} to @code{2.0}. The default value is "1".
6877 Set the brightness expression. The value must be a float value in
6878 range @code{-1.0} to @code{1.0}. The default value is "0".
6881 Set the saturation expression. The value must be a float in
6882 range @code{0.0} to @code{3.0}. The default value is "1".
6885 Set the gamma expression. The value must be a float in range
6886 @code{0.1} to @code{10.0}. The default value is "1".
6889 Set the gamma expression for red. The value must be a float in
6890 range @code{0.1} to @code{10.0}. The default value is "1".
6893 Set the gamma expression for green. The value must be a float in range
6894 @code{0.1} to @code{10.0}. The default value is "1".
6897 Set the gamma expression for blue. The value must be a float in range
6898 @code{0.1} to @code{10.0}. The default value is "1".
6901 Set the gamma weight expression. It can be used to reduce the effect
6902 of a high gamma value on bright image areas, e.g. keep them from
6903 getting overamplified and just plain white. The value must be a float
6904 in range @code{0.0} to @code{1.0}. A value of @code{0.0} turns the
6905 gamma correction all the way down while @code{1.0} leaves it at its
6906 full strength. Default is "1".
6909 Set when the expressions for brightness, contrast, saturation and
6910 gamma expressions are evaluated.
6912 It accepts the following values:
6915 only evaluate expressions once during the filter initialization or
6916 when a command is processed
6919 evaluate expressions for each incoming frame
6922 Default value is @samp{init}.
6925 The expressions accept the following parameters:
6928 frame count of the input frame starting from 0
6931 byte position of the corresponding packet in the input file, NAN if
6935 frame rate of the input video, NAN if the input frame rate is unknown
6938 timestamp expressed in seconds, NAN if the input timestamp is unknown
6941 @subsection Commands
6942 The filter supports the following commands:
6946 Set the contrast expression.
6949 Set the brightness expression.
6952 Set the saturation expression.
6955 Set the gamma expression.
6958 Set the gamma_r expression.
6961 Set gamma_g expression.
6964 Set gamma_b expression.
6967 Set gamma_weight expression.
6969 The command accepts the same syntax of the corresponding option.
6971 If the specified expression is not valid, it is kept at its current
6978 Apply erosion effect to the video.
6980 This filter replaces the pixel by the local(3x3) minimum.
6982 It accepts the following options:
6989 Limit the maximum change for each plane, default is 65535.
6990 If 0, plane will remain unchanged.
6993 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
6996 Flags to local 3x3 coordinates maps like this:
7003 @section extractplanes
7005 Extract color channel components from input video stream into
7006 separate grayscale video streams.
7008 The filter accepts the following option:
7012 Set plane(s) to extract.
7014 Available values for planes are:
7025 Choosing planes not available in the input will result in an error.
7026 That means you cannot select @code{r}, @code{g}, @code{b} planes
7027 with @code{y}, @code{u}, @code{v} planes at same time.
7030 @subsection Examples
7034 Extract luma, u and v color channel component from input video frame
7035 into 3 grayscale outputs:
7037 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
7043 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
7045 For each input image, the filter will compute the optimal mapping from
7046 the input to the output given the codebook length, that is the number
7047 of distinct output colors.
7049 This filter accepts the following options.
7052 @item codebook_length, l
7053 Set codebook length. The value must be a positive integer, and
7054 represents the number of distinct output colors. Default value is 256.
7057 Set the maximum number of iterations to apply for computing the optimal
7058 mapping. The higher the value the better the result and the higher the
7059 computation time. Default value is 1.
7062 Set a random seed, must be an integer included between 0 and
7063 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
7064 will try to use a good random seed on a best effort basis.
7067 Set pal8 output pixel format. This option does not work with codebook
7068 length greater than 256.
7073 Apply a fade-in/out effect to the input video.
7075 It accepts the following parameters:
7079 The effect type can be either "in" for a fade-in, or "out" for a fade-out
7081 Default is @code{in}.
7083 @item start_frame, s
7084 Specify the number of the frame to start applying the fade
7085 effect at. Default is 0.
7088 The number of frames that the fade effect lasts. At the end of the
7089 fade-in effect, the output video will have the same intensity as the input video.
7090 At the end of the fade-out transition, the output video will be filled with the
7091 selected @option{color}.
7095 If set to 1, fade only alpha channel, if one exists on the input.
7098 @item start_time, st
7099 Specify the timestamp (in seconds) of the frame to start to apply the fade
7100 effect. If both start_frame and start_time are specified, the fade will start at
7101 whichever comes last. Default is 0.
7104 The number of seconds for which the fade effect has to last. At the end of the
7105 fade-in effect the output video will have the same intensity as the input video,
7106 at the end of the fade-out transition the output video will be filled with the
7107 selected @option{color}.
7108 If both duration and nb_frames are specified, duration is used. Default is 0
7109 (nb_frames is used by default).
7112 Specify the color of the fade. Default is "black".
7115 @subsection Examples
7119 Fade in the first 30 frames of video:
7124 The command above is equivalent to:
7130 Fade out the last 45 frames of a 200-frame video:
7133 fade=type=out:start_frame=155:nb_frames=45
7137 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
7139 fade=in:0:25, fade=out:975:25
7143 Make the first 5 frames yellow, then fade in from frame 5-24:
7145 fade=in:5:20:color=yellow
7149 Fade in alpha over first 25 frames of video:
7151 fade=in:0:25:alpha=1
7155 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
7157 fade=t=in:st=5.5:d=0.5
7163 Apply arbitrary expressions to samples in frequency domain
7167 Adjust the dc value (gain) of the luma plane of the image. The filter
7168 accepts an integer value in range @code{0} to @code{1000}. The default
7169 value is set to @code{0}.
7172 Adjust the dc value (gain) of the 1st chroma plane of the image. The
7173 filter accepts an integer value in range @code{0} to @code{1000}. The
7174 default value is set to @code{0}.
7177 Adjust the dc value (gain) of the 2nd chroma plane of the image. The
7178 filter accepts an integer value in range @code{0} to @code{1000}. The
7179 default value is set to @code{0}.
7182 Set the frequency domain weight expression for the luma plane.
7185 Set the frequency domain weight expression for the 1st chroma plane.
7188 Set the frequency domain weight expression for the 2nd chroma plane.
7190 The filter accepts the following variables:
7193 The coordinates of the current sample.
7197 The width and height of the image.
7200 @subsection Examples
7206 fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
7212 fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
7218 fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
7224 fftfilt=dc_Y=0:weight_Y='exp(-4 * ((Y+X)/(W+H)))'
7231 Extract a single field from an interlaced image using stride
7232 arithmetic to avoid wasting CPU time. The output frames are marked as
7235 The filter accepts the following options:
7239 Specify whether to extract the top (if the value is @code{0} or
7240 @code{top}) or the bottom field (if the value is @code{1} or
7246 Create new frames by copying the top and bottom fields from surrounding frames
7247 supplied as numbers by the hint file.
7251 Set file containing hints: absolute/relative frame numbers.
7253 There must be one line for each frame in a clip. Each line must contain two
7254 numbers separated by the comma, optionally followed by @code{-} or @code{+}.
7255 Numbers supplied on each line of file can not be out of [N-1,N+1] where N
7256 is current frame number for @code{absolute} mode or out of [-1, 1] range
7257 for @code{relative} mode. First number tells from which frame to pick up top
7258 field and second number tells from which frame to pick up bottom field.
7260 If optionally followed by @code{+} output frame will be marked as interlaced,
7261 else if followed by @code{-} output frame will be marked as progressive, else
7262 it will be marked same as input frame.
7263 If line starts with @code{#} or @code{;} that line is skipped.
7266 Can be item @code{absolute} or @code{relative}. Default is @code{absolute}.
7269 Example of first several lines of @code{hint} file for @code{relative} mode:
7272 1,0 - # second frame, use third's frame top field and second's frame bottom field
7273 1,0 - # third frame, use fourth's frame top field and third's frame bottom field
7290 Field matching filter for inverse telecine. It is meant to reconstruct the
7291 progressive frames from a telecined stream. The filter does not drop duplicated
7292 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
7293 followed by a decimation filter such as @ref{decimate} in the filtergraph.
7295 The separation of the field matching and the decimation is notably motivated by
7296 the possibility of inserting a de-interlacing filter fallback between the two.
7297 If the source has mixed telecined and real interlaced content,
7298 @code{fieldmatch} will not be able to match fields for the interlaced parts.
7299 But these remaining combed frames will be marked as interlaced, and thus can be
7300 de-interlaced by a later filter such as @ref{yadif} before decimation.
7302 In addition to the various configuration options, @code{fieldmatch} can take an
7303 optional second stream, activated through the @option{ppsrc} option. If
7304 enabled, the frames reconstruction will be based on the fields and frames from
7305 this second stream. This allows the first input to be pre-processed in order to
7306 help the various algorithms of the filter, while keeping the output lossless
7307 (assuming the fields are matched properly). Typically, a field-aware denoiser,
7308 or brightness/contrast adjustments can help.
7310 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
7311 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
7312 which @code{fieldmatch} is based on. While the semantic and usage are very
7313 close, some behaviour and options names can differ.
7315 The @ref{decimate} filter currently only works for constant frame rate input.
7316 If your input has mixed telecined (30fps) and progressive content with a lower
7317 framerate like 24fps use the following filterchain to produce the necessary cfr
7318 stream: @code{dejudder,fps=30000/1001,fieldmatch,decimate}.
7320 The filter accepts the following options:
7324 Specify the assumed field order of the input stream. Available values are:
7328 Auto detect parity (use FFmpeg's internal parity value).
7330 Assume bottom field first.
7332 Assume top field first.
7335 Note that it is sometimes recommended not to trust the parity announced by the
7338 Default value is @var{auto}.
7341 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
7342 sense that it won't risk creating jerkiness due to duplicate frames when
7343 possible, but if there are bad edits or blended fields it will end up
7344 outputting combed frames when a good match might actually exist. On the other
7345 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
7346 but will almost always find a good frame if there is one. The other values are
7347 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
7348 jerkiness and creating duplicate frames versus finding good matches in sections
7349 with bad edits, orphaned fields, blended fields, etc.
7351 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
7353 Available values are:
7357 2-way matching (p/c)
7359 2-way matching, and trying 3rd match if still combed (p/c + n)
7361 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
7363 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
7364 still combed (p/c + n + u/b)
7366 3-way matching (p/c/n)
7368 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
7369 detected as combed (p/c/n + u/b)
7372 The parenthesis at the end indicate the matches that would be used for that
7373 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
7376 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
7379 Default value is @var{pc_n}.
7382 Mark the main input stream as a pre-processed input, and enable the secondary
7383 input stream as the clean source to pick the fields from. See the filter
7384 introduction for more details. It is similar to the @option{clip2} feature from
7387 Default value is @code{0} (disabled).
7390 Set the field to match from. It is recommended to set this to the same value as
7391 @option{order} unless you experience matching failures with that setting. In
7392 certain circumstances changing the field that is used to match from can have a
7393 large impact on matching performance. Available values are:
7397 Automatic (same value as @option{order}).
7399 Match from the bottom field.
7401 Match from the top field.
7404 Default value is @var{auto}.
7407 Set whether or not chroma is included during the match comparisons. In most
7408 cases it is recommended to leave this enabled. You should set this to @code{0}
7409 only if your clip has bad chroma problems such as heavy rainbowing or other
7410 artifacts. Setting this to @code{0} could also be used to speed things up at
7411 the cost of some accuracy.
7413 Default value is @code{1}.
7417 These define an exclusion band which excludes the lines between @option{y0} and
7418 @option{y1} from being included in the field matching decision. An exclusion
7419 band can be used to ignore subtitles, a logo, or other things that may
7420 interfere with the matching. @option{y0} sets the starting scan line and
7421 @option{y1} sets the ending line; all lines in between @option{y0} and
7422 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
7423 @option{y0} and @option{y1} to the same value will disable the feature.
7424 @option{y0} and @option{y1} defaults to @code{0}.
7427 Set the scene change detection threshold as a percentage of maximum change on
7428 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
7429 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
7430 @option{scthresh} is @code{[0.0, 100.0]}.
7432 Default value is @code{12.0}.
7435 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
7436 account the combed scores of matches when deciding what match to use as the
7437 final match. Available values are:
7441 No final matching based on combed scores.
7443 Combed scores are only used when a scene change is detected.
7445 Use combed scores all the time.
7448 Default is @var{sc}.
7451 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
7452 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
7453 Available values are:
7457 No forced calculation.
7459 Force p/c/n calculations.
7461 Force p/c/n/u/b calculations.
7464 Default value is @var{none}.
7467 This is the area combing threshold used for combed frame detection. This
7468 essentially controls how "strong" or "visible" combing must be to be detected.
7469 Larger values mean combing must be more visible and smaller values mean combing
7470 can be less visible or strong and still be detected. Valid settings are from
7471 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
7472 be detected as combed). This is basically a pixel difference value. A good
7473 range is @code{[8, 12]}.
7475 Default value is @code{9}.
7478 Sets whether or not chroma is considered in the combed frame decision. Only
7479 disable this if your source has chroma problems (rainbowing, etc.) that are
7480 causing problems for the combed frame detection with chroma enabled. Actually,
7481 using @option{chroma}=@var{0} is usually more reliable, except for the case
7482 where there is chroma only combing in the source.
7484 Default value is @code{0}.
7488 Respectively set the x-axis and y-axis size of the window used during combed
7489 frame detection. This has to do with the size of the area in which
7490 @option{combpel} pixels are required to be detected as combed for a frame to be
7491 declared combed. See the @option{combpel} parameter description for more info.
7492 Possible values are any number that is a power of 2 starting at 4 and going up
7495 Default value is @code{16}.
7498 The number of combed pixels inside any of the @option{blocky} by
7499 @option{blockx} size blocks on the frame for the frame to be detected as
7500 combed. While @option{cthresh} controls how "visible" the combing must be, this
7501 setting controls "how much" combing there must be in any localized area (a
7502 window defined by the @option{blockx} and @option{blocky} settings) on the
7503 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
7504 which point no frames will ever be detected as combed). This setting is known
7505 as @option{MI} in TFM/VFM vocabulary.
7507 Default value is @code{80}.
7510 @anchor{p/c/n/u/b meaning}
7511 @subsection p/c/n/u/b meaning
7513 @subsubsection p/c/n
7515 We assume the following telecined stream:
7518 Top fields: 1 2 2 3 4
7519 Bottom fields: 1 2 3 4 4
7522 The numbers correspond to the progressive frame the fields relate to. Here, the
7523 first two frames are progressive, the 3rd and 4th are combed, and so on.
7525 When @code{fieldmatch} is configured to run a matching from bottom
7526 (@option{field}=@var{bottom}) this is how this input stream get transformed:
7531 B 1 2 3 4 4 <-- matching reference
7540 As a result of the field matching, we can see that some frames get duplicated.
7541 To perform a complete inverse telecine, you need to rely on a decimation filter
7542 after this operation. See for instance the @ref{decimate} filter.
7544 The same operation now matching from top fields (@option{field}=@var{top})
7549 T 1 2 2 3 4 <-- matching reference
7559 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
7560 basically, they refer to the frame and field of the opposite parity:
7563 @item @var{p} matches the field of the opposite parity in the previous frame
7564 @item @var{c} matches the field of the opposite parity in the current frame
7565 @item @var{n} matches the field of the opposite parity in the next frame
7570 The @var{u} and @var{b} matching are a bit special in the sense that they match
7571 from the opposite parity flag. In the following examples, we assume that we are
7572 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
7573 'x' is placed above and below each matched fields.
7575 With bottom matching (@option{field}=@var{bottom}):
7580 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
7581 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
7589 With top matching (@option{field}=@var{top}):
7594 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
7595 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
7603 @subsection Examples
7605 Simple IVTC of a top field first telecined stream:
7607 fieldmatch=order=tff:combmatch=none, decimate
7610 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
7612 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
7617 Transform the field order of the input video.
7619 It accepts the following parameters:
7624 The output field order. Valid values are @var{tff} for top field first or @var{bff}
7625 for bottom field first.
7628 The default value is @samp{tff}.
7630 The transformation is done by shifting the picture content up or down
7631 by one line, and filling the remaining line with appropriate picture content.
7632 This method is consistent with most broadcast field order converters.
7634 If the input video is not flagged as being interlaced, or it is already
7635 flagged as being of the required output field order, then this filter does
7636 not alter the incoming video.
7638 It is very useful when converting to or from PAL DV material,
7639 which is bottom field first.
7643 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
7646 @section fifo, afifo
7648 Buffer input images and send them when they are requested.
7650 It is mainly useful when auto-inserted by the libavfilter
7653 It does not take parameters.
7657 Find a rectangular object
7659 It accepts the following options:
7663 Filepath of the object image, needs to be in gray8.
7666 Detection threshold, default is 0.5.
7669 Number of mipmaps, default is 3.
7671 @item xmin, ymin, xmax, ymax
7672 Specifies the rectangle in which to search.
7675 @subsection Examples
7679 Generate a representative palette of a given video using @command{ffmpeg}:
7681 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
7687 Cover a rectangular object
7689 It accepts the following options:
7693 Filepath of the optional cover image, needs to be in yuv420.
7698 It accepts the following values:
7701 cover it by the supplied image
7703 cover it by interpolating the surrounding pixels
7706 Default value is @var{blur}.
7709 @subsection Examples
7713 Generate a representative palette of a given video using @command{ffmpeg}:
7715 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
7722 Convert the input video to one of the specified pixel formats.
7723 Libavfilter will try to pick one that is suitable as input to
7726 It accepts the following parameters:
7730 A '|'-separated list of pixel format names, such as
7731 "pix_fmts=yuv420p|monow|rgb24".
7735 @subsection Examples
7739 Convert the input video to the @var{yuv420p} format
7741 format=pix_fmts=yuv420p
7744 Convert the input video to any of the formats in the list
7746 format=pix_fmts=yuv420p|yuv444p|yuv410p
7753 Convert the video to specified constant frame rate by duplicating or dropping
7754 frames as necessary.
7756 It accepts the following parameters:
7760 The desired output frame rate. The default is @code{25}.
7765 Possible values are:
7768 zero round towards 0
7772 round towards -infinity
7774 round towards +infinity
7778 The default is @code{near}.
7781 Assume the first PTS should be the given value, in seconds. This allows for
7782 padding/trimming at the start of stream. By default, no assumption is made
7783 about the first frame's expected PTS, so no padding or trimming is done.
7784 For example, this could be set to 0 to pad the beginning with duplicates of
7785 the first frame if a video stream starts after the audio stream or to trim any
7786 frames with a negative PTS.
7790 Alternatively, the options can be specified as a flat string:
7791 @var{fps}[:@var{round}].
7793 See also the @ref{setpts} filter.
7795 @subsection Examples
7799 A typical usage in order to set the fps to 25:
7805 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
7807 fps=fps=film:round=near
7813 Pack two different video streams into a stereoscopic video, setting proper
7814 metadata on supported codecs. The two views should have the same size and
7815 framerate and processing will stop when the shorter video ends. Please note
7816 that you may conveniently adjust view properties with the @ref{scale} and
7819 It accepts the following parameters:
7823 The desired packing format. Supported values are:
7828 The views are next to each other (default).
7831 The views are on top of each other.
7834 The views are packed by line.
7837 The views are packed by column.
7840 The views are temporally interleaved.
7849 # Convert left and right views into a frame-sequential video
7850 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
7852 # Convert views into a side-by-side video with the same output resolution as the input
7853 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
7858 Change the frame rate by interpolating new video output frames from the source
7861 This filter is not designed to function correctly with interlaced media. If
7862 you wish to change the frame rate of interlaced media then you are required
7863 to deinterlace before this filter and re-interlace after this filter.
7865 A description of the accepted options follows.
7869 Specify the output frames per second. This option can also be specified
7870 as a value alone. The default is @code{50}.
7873 Specify the start of a range where the output frame will be created as a
7874 linear interpolation of two frames. The range is [@code{0}-@code{255}],
7875 the default is @code{15}.
7878 Specify the end of a range where the output frame will be created as a
7879 linear interpolation of two frames. The range is [@code{0}-@code{255}],
7880 the default is @code{240}.
7883 Specify the level at which a scene change is detected as a value between
7884 0 and 100 to indicate a new scene; a low value reflects a low
7885 probability for the current frame to introduce a new scene, while a higher
7886 value means the current frame is more likely to be one.
7887 The default is @code{7}.
7890 Specify flags influencing the filter process.
7892 Available value for @var{flags} is:
7895 @item scene_change_detect, scd
7896 Enable scene change detection using the value of the option @var{scene}.
7897 This flag is enabled by default.
7903 Select one frame every N-th frame.
7905 This filter accepts the following option:
7908 Select frame after every @code{step} frames.
7909 Allowed values are positive integers higher than 0. Default value is @code{1}.
7915 Apply a frei0r effect to the input video.
7917 To enable the compilation of this filter, you need to install the frei0r
7918 header and configure FFmpeg with @code{--enable-frei0r}.
7920 It accepts the following parameters:
7925 The name of the frei0r effect to load. If the environment variable
7926 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
7927 directories specified by the colon-separated list in @env{FREIOR_PATH}.
7928 Otherwise, the standard frei0r paths are searched, in this order:
7929 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
7930 @file{/usr/lib/frei0r-1/}.
7933 A '|'-separated list of parameters to pass to the frei0r effect.
7937 A frei0r effect parameter can be a boolean (its value is either
7938 "y" or "n"), a double, a color (specified as
7939 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
7940 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
7941 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
7942 @var{X} and @var{Y} are floating point numbers) and/or a string.
7944 The number and types of parameters depend on the loaded effect. If an
7945 effect parameter is not specified, the default value is set.
7947 @subsection Examples
7951 Apply the distort0r effect, setting the first two double parameters:
7953 frei0r=filter_name=distort0r:filter_params=0.5|0.01
7957 Apply the colordistance effect, taking a color as the first parameter:
7959 frei0r=colordistance:0.2/0.3/0.4
7960 frei0r=colordistance:violet
7961 frei0r=colordistance:0x112233
7965 Apply the perspective effect, specifying the top left and top right image
7968 frei0r=perspective:0.2/0.2|0.8/0.2
7972 For more information, see
7973 @url{http://frei0r.dyne.org}
7977 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
7979 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
7980 processing filter, one of them is performed once per block, not per pixel.
7981 This allows for much higher speed.
7983 The filter accepts the following options:
7987 Set quality. This option defines the number of levels for averaging. It accepts
7988 an integer in the range 4-5. Default value is @code{4}.
7991 Force a constant quantization parameter. It accepts an integer in range 0-63.
7992 If not set, the filter will use the QP from the video stream (if available).
7995 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
7996 more details but also more artifacts, while higher values make the image smoother
7997 but also blurrier. Default value is @code{0} − PSNR optimal.
8000 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8001 option may cause flicker since the B-Frames have often larger QP. Default is
8002 @code{0} (not enabled).
8008 The filter accepts the following options:
8012 Set the luminance expression.
8014 Set the chrominance blue expression.
8016 Set the chrominance red expression.
8018 Set the alpha expression.
8020 Set the red expression.
8022 Set the green expression.
8024 Set the blue expression.
8027 The colorspace is selected according to the specified options. If one
8028 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
8029 options is specified, the filter will automatically select a YCbCr
8030 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
8031 @option{blue_expr} options is specified, it will select an RGB
8034 If one of the chrominance expression is not defined, it falls back on the other
8035 one. If no alpha expression is specified it will evaluate to opaque value.
8036 If none of chrominance expressions are specified, they will evaluate
8037 to the luminance expression.
8039 The expressions can use the following variables and functions:
8043 The sequential number of the filtered frame, starting from @code{0}.
8047 The coordinates of the current sample.
8051 The width and height of the image.
8055 Width and height scale depending on the currently filtered plane. It is the
8056 ratio between the corresponding luma plane number of pixels and the current
8057 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
8058 @code{0.5,0.5} for chroma planes.
8061 Time of the current frame, expressed in seconds.
8064 Return the value of the pixel at location (@var{x},@var{y}) of the current
8068 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
8072 Return the value of the pixel at location (@var{x},@var{y}) of the
8073 blue-difference chroma plane. Return 0 if there is no such plane.
8076 Return the value of the pixel at location (@var{x},@var{y}) of the
8077 red-difference chroma plane. Return 0 if there is no such plane.
8082 Return the value of the pixel at location (@var{x},@var{y}) of the
8083 red/green/blue component. Return 0 if there is no such component.
8086 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
8087 plane. Return 0 if there is no such plane.
8090 For functions, if @var{x} and @var{y} are outside the area, the value will be
8091 automatically clipped to the closer edge.
8093 @subsection Examples
8097 Flip the image horizontally:
8103 Generate a bidimensional sine wave, with angle @code{PI/3} and a
8104 wavelength of 100 pixels:
8106 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
8110 Generate a fancy enigmatic moving light:
8112 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
8116 Generate a quick emboss effect:
8118 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
8122 Modify RGB components depending on pixel position:
8124 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
8128 Create a radial gradient that is the same size as the input (also see
8129 the @ref{vignette} filter):
8131 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
8137 Fix the banding artifacts that are sometimes introduced into nearly flat
8138 regions by truncation to 8bit color depth.
8139 Interpolate the gradients that should go where the bands are, and
8142 It is designed for playback only. Do not use it prior to
8143 lossy compression, because compression tends to lose the dither and
8144 bring back the bands.
8146 It accepts the following parameters:
8151 The maximum amount by which the filter will change any one pixel. This is also
8152 the threshold for detecting nearly flat regions. Acceptable values range from
8153 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
8157 The neighborhood to fit the gradient to. A larger radius makes for smoother
8158 gradients, but also prevents the filter from modifying the pixels near detailed
8159 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
8160 values will be clipped to the valid range.
8164 Alternatively, the options can be specified as a flat string:
8165 @var{strength}[:@var{radius}]
8167 @subsection Examples
8171 Apply the filter with a @code{3.5} strength and radius of @code{8}:
8177 Specify radius, omitting the strength (which will fall-back to the default
8188 Apply a Hald CLUT to a video stream.
8190 First input is the video stream to process, and second one is the Hald CLUT.
8191 The Hald CLUT input can be a simple picture or a complete video stream.
8193 The filter accepts the following options:
8197 Force termination when the shortest input terminates. Default is @code{0}.
8199 Continue applying the last CLUT after the end of the stream. A value of
8200 @code{0} disable the filter after the last frame of the CLUT is reached.
8201 Default is @code{1}.
8204 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
8205 filters share the same internals).
8207 More information about the Hald CLUT can be found on Eskil Steenberg's website
8208 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
8210 @subsection Workflow examples
8212 @subsubsection Hald CLUT video stream
8214 Generate an identity Hald CLUT stream altered with various effects:
8216 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
8219 Note: make sure you use a lossless codec.
8221 Then use it with @code{haldclut} to apply it on some random stream:
8223 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
8226 The Hald CLUT will be applied to the 10 first seconds (duration of
8227 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
8228 to the remaining frames of the @code{mandelbrot} stream.
8230 @subsubsection Hald CLUT with preview
8232 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
8233 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
8234 biggest possible square starting at the top left of the picture. The remaining
8235 padding pixels (bottom or right) will be ignored. This area can be used to add
8236 a preview of the Hald CLUT.
8238 Typically, the following generated Hald CLUT will be supported by the
8239 @code{haldclut} filter:
8242 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
8243 pad=iw+320 [padded_clut];
8244 smptebars=s=320x256, split [a][b];
8245 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
8246 [main][b] overlay=W-320" -frames:v 1 clut.png
8249 It contains the original and a preview of the effect of the CLUT: SMPTE color
8250 bars are displayed on the right-top, and below the same color bars processed by
8253 Then, the effect of this Hald CLUT can be visualized with:
8255 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
8260 Decodes high definition audio cd data. 16-Bit PCM stream containing hdcd flags
8261 is converted to 20-bit PCM stream.
8265 Flip the input video horizontally.
8267 For example, to horizontally flip the input video with @command{ffmpeg}:
8269 ffmpeg -i in.avi -vf "hflip" out.avi
8273 This filter applies a global color histogram equalization on a
8276 It can be used to correct video that has a compressed range of pixel
8277 intensities. The filter redistributes the pixel intensities to
8278 equalize their distribution across the intensity range. It may be
8279 viewed as an "automatically adjusting contrast filter". This filter is
8280 useful only for correcting degraded or poorly captured source
8283 The filter accepts the following options:
8287 Determine the amount of equalization to be applied. As the strength
8288 is reduced, the distribution of pixel intensities more-and-more
8289 approaches that of the input frame. The value must be a float number
8290 in the range [0,1] and defaults to 0.200.
8293 Set the maximum intensity that can generated and scale the output
8294 values appropriately. The strength should be set as desired and then
8295 the intensity can be limited if needed to avoid washing-out. The value
8296 must be a float number in the range [0,1] and defaults to 0.210.
8299 Set the antibanding level. If enabled the filter will randomly vary
8300 the luminance of output pixels by a small amount to avoid banding of
8301 the histogram. Possible values are @code{none}, @code{weak} or
8302 @code{strong}. It defaults to @code{none}.
8307 Compute and draw a color distribution histogram for the input video.
8309 The computed histogram is a representation of the color component
8310 distribution in an image.
8312 Standard histogram displays the color components distribution in an image.
8313 Displays color graph for each color component. Shows distribution of
8314 the Y, U, V, A or R, G, B components, depending on input format, in the
8315 current frame. Below each graph a color component scale meter is shown.
8317 The filter accepts the following options:
8321 Set height of level. Default value is @code{200}.
8322 Allowed range is [50, 2048].
8325 Set height of color scale. Default value is @code{12}.
8326 Allowed range is [0, 40].
8330 It accepts the following values:
8333 Per color component graphs are placed below each other.
8336 Presents information identical to that in the @code{parade}, except
8337 that the graphs representing color components are superimposed directly
8340 Default is @code{parade}.
8343 Set mode. Can be either @code{linear}, or @code{logarithmic}.
8344 Default is @code{linear}.
8347 Set what color components to display.
8348 Default is @code{7}.
8351 @subsection Examples
8356 Calculate and draw histogram:
8358 ffplay -i input -vf histogram
8366 This is a high precision/quality 3d denoise filter. It aims to reduce
8367 image noise, producing smooth images and making still images really
8368 still. It should enhance compressibility.
8370 It accepts the following optional parameters:
8374 A non-negative floating point number which specifies spatial luma strength.
8377 @item chroma_spatial
8378 A non-negative floating point number which specifies spatial chroma strength.
8379 It defaults to 3.0*@var{luma_spatial}/4.0.
8382 A floating point number which specifies luma temporal strength. It defaults to
8383 6.0*@var{luma_spatial}/4.0.
8386 A floating point number which specifies chroma temporal strength. It defaults to
8387 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
8390 @anchor{hwupload_cuda}
8391 @section hwupload_cuda
8393 Upload system memory frames to a CUDA device.
8395 It accepts the following optional parameters:
8399 The number of the CUDA device to use
8404 Apply a high-quality magnification filter designed for pixel art. This filter
8405 was originally created by Maxim Stepin.
8407 It accepts the following option:
8411 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
8412 @code{hq3x} and @code{4} for @code{hq4x}.
8413 Default is @code{3}.
8417 Stack input videos horizontally.
8419 All streams must be of same pixel format and of same height.
8421 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
8422 to create same output.
8424 The filter accept the following option:
8428 Set number of input streams. Default is 2.
8431 If set to 1, force the output to terminate when the shortest input
8432 terminates. Default value is 0.
8437 Modify the hue and/or the saturation of the input.
8439 It accepts the following parameters:
8443 Specify the hue angle as a number of degrees. It accepts an expression,
8444 and defaults to "0".
8447 Specify the saturation in the [-10,10] range. It accepts an expression and
8451 Specify the hue angle as a number of radians. It accepts an
8452 expression, and defaults to "0".
8455 Specify the brightness in the [-10,10] range. It accepts an expression and
8459 @option{h} and @option{H} are mutually exclusive, and can't be
8460 specified at the same time.
8462 The @option{b}, @option{h}, @option{H} and @option{s} option values are
8463 expressions containing the following constants:
8467 frame count of the input frame starting from 0
8470 presentation timestamp of the input frame expressed in time base units
8473 frame rate of the input video, NAN if the input frame rate is unknown
8476 timestamp expressed in seconds, NAN if the input timestamp is unknown
8479 time base of the input video
8482 @subsection Examples
8486 Set the hue to 90 degrees and the saturation to 1.0:
8492 Same command but expressing the hue in radians:
8498 Rotate hue and make the saturation swing between 0
8499 and 2 over a period of 1 second:
8501 hue="H=2*PI*t: s=sin(2*PI*t)+1"
8505 Apply a 3 seconds saturation fade-in effect starting at 0:
8510 The general fade-in expression can be written as:
8512 hue="s=min(0\, max((t-START)/DURATION\, 1))"
8516 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
8518 hue="s=max(0\, min(1\, (8-t)/3))"
8521 The general fade-out expression can be written as:
8523 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
8528 @subsection Commands
8530 This filter supports the following commands:
8536 Modify the hue and/or the saturation and/or brightness of the input video.
8537 The command accepts the same syntax of the corresponding option.
8539 If the specified expression is not valid, it is kept at its current
8545 Detect video interlacing type.
8547 This filter tries to detect if the input frames as interlaced, progressive,
8548 top or bottom field first. It will also try and detect fields that are
8549 repeated between adjacent frames (a sign of telecine).
8551 Single frame detection considers only immediately adjacent frames when classifying each frame.
8552 Multiple frame detection incorporates the classification history of previous frames.
8554 The filter will log these metadata values:
8557 @item single.current_frame
8558 Detected type of current frame using single-frame detection. One of:
8559 ``tff'' (top field first), ``bff'' (bottom field first),
8560 ``progressive'', or ``undetermined''
8563 Cumulative number of frames detected as top field first using single-frame detection.
8566 Cumulative number of frames detected as top field first using multiple-frame detection.
8569 Cumulative number of frames detected as bottom field first using single-frame detection.
8571 @item multiple.current_frame
8572 Detected type of current frame using multiple-frame detection. One of:
8573 ``tff'' (top field first), ``bff'' (bottom field first),
8574 ``progressive'', or ``undetermined''
8577 Cumulative number of frames detected as bottom field first using multiple-frame detection.
8579 @item single.progressive
8580 Cumulative number of frames detected as progressive using single-frame detection.
8582 @item multiple.progressive
8583 Cumulative number of frames detected as progressive using multiple-frame detection.
8585 @item single.undetermined
8586 Cumulative number of frames that could not be classified using single-frame detection.
8588 @item multiple.undetermined
8589 Cumulative number of frames that could not be classified using multiple-frame detection.
8591 @item repeated.current_frame
8592 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
8594 @item repeated.neither
8595 Cumulative number of frames with no repeated field.
8598 Cumulative number of frames with the top field repeated from the previous frame's top field.
8600 @item repeated.bottom
8601 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
8604 The filter accepts the following options:
8608 Set interlacing threshold.
8610 Set progressive threshold.
8612 Threshold for repeated field detection.
8614 Number of frames after which a given frame's contribution to the
8615 statistics is halved (i.e., it contributes only 0.5 to it's
8616 classification). The default of 0 means that all frames seen are given
8617 full weight of 1.0 forever.
8618 @item analyze_interlaced_flag
8619 When this is not 0 then idet will use the specified number of frames to determine
8620 if the interlaced flag is accurate, it will not count undetermined frames.
8621 If the flag is found to be accurate it will be used without any further
8622 computations, if it is found to be inaccurate it will be cleared without any
8623 further computations. This allows inserting the idet filter as a low computational
8624 method to clean up the interlaced flag
8629 Deinterleave or interleave fields.
8631 This filter allows one to process interlaced images fields without
8632 deinterlacing them. Deinterleaving splits the input frame into 2
8633 fields (so called half pictures). Odd lines are moved to the top
8634 half of the output image, even lines to the bottom half.
8635 You can process (filter) them independently and then re-interleave them.
8637 The filter accepts the following options:
8641 @item chroma_mode, c
8643 Available values for @var{luma_mode}, @var{chroma_mode} and
8644 @var{alpha_mode} are:
8650 @item deinterleave, d
8651 Deinterleave fields, placing one above the other.
8654 Interleave fields. Reverse the effect of deinterleaving.
8656 Default value is @code{none}.
8659 @item chroma_swap, cs
8660 @item alpha_swap, as
8661 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
8666 Apply inflate effect to the video.
8668 This filter replaces the pixel by the local(3x3) average by taking into account
8669 only values higher than the pixel.
8671 It accepts the following options:
8678 Limit the maximum change for each plane, default is 65535.
8679 If 0, plane will remain unchanged.
8684 Simple interlacing filter from progressive contents. This interleaves upper (or
8685 lower) lines from odd frames with lower (or upper) lines from even frames,
8686 halving the frame rate and preserving image height.
8689 Original Original New Frame
8690 Frame 'j' Frame 'j+1' (tff)
8691 ========== =========== ==================
8692 Line 0 --------------------> Frame 'j' Line 0
8693 Line 1 Line 1 ----> Frame 'j+1' Line 1
8694 Line 2 ---------------------> Frame 'j' Line 2
8695 Line 3 Line 3 ----> Frame 'j+1' Line 3
8697 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
8700 It accepts the following optional parameters:
8704 This determines whether the interlaced frame is taken from the even
8705 (tff - default) or odd (bff) lines of the progressive frame.
8708 Enable (default) or disable the vertical lowpass filter to avoid twitter
8709 interlacing and reduce moire patterns.
8714 Deinterlace input video by applying Donald Graft's adaptive kernel
8715 deinterling. Work on interlaced parts of a video to produce
8718 The description of the accepted parameters follows.
8722 Set the threshold which affects the filter's tolerance when
8723 determining if a pixel line must be processed. It must be an integer
8724 in the range [0,255] and defaults to 10. A value of 0 will result in
8725 applying the process on every pixels.
8728 Paint pixels exceeding the threshold value to white if set to 1.
8732 Set the fields order. Swap fields if set to 1, leave fields alone if
8736 Enable additional sharpening if set to 1. Default is 0.
8739 Enable twoway sharpening if set to 1. Default is 0.
8742 @subsection Examples
8746 Apply default values:
8748 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
8752 Enable additional sharpening:
8758 Paint processed pixels in white:
8764 @section lenscorrection
8766 Correct radial lens distortion
8768 This filter can be used to correct for radial distortion as can result from the use
8769 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
8770 one can use tools available for example as part of opencv or simply trial-and-error.
8771 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
8772 and extract the k1 and k2 coefficients from the resulting matrix.
8774 Note that effectively the same filter is available in the open-source tools Krita and
8775 Digikam from the KDE project.
8777 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
8778 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
8779 brightness distribution, so you may want to use both filters together in certain
8780 cases, though you will have to take care of ordering, i.e. whether vignetting should
8781 be applied before or after lens correction.
8785 The filter accepts the following options:
8789 Relative x-coordinate of the focal point of the image, and thereby the center of the
8790 distortion. This value has a range [0,1] and is expressed as fractions of the image
8793 Relative y-coordinate of the focal point of the image, and thereby the center of the
8794 distortion. This value has a range [0,1] and is expressed as fractions of the image
8797 Coefficient of the quadratic correction term. 0.5 means no correction.
8799 Coefficient of the double quadratic correction term. 0.5 means no correction.
8802 The formula that generates the correction is:
8804 @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)
8806 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
8807 distances from the focal point in the source and target images, respectively.
8809 @section loop, aloop
8811 Loop video frames or audio samples.
8813 Those filters accepts the following options:
8817 Set the number of loops.
8820 Set maximal size in number of frames for @code{loop} filter or maximal number
8821 of samples in case of @code{aloop} filter.
8824 Set first frame of loop for @code{loop} filter or first sample of loop in case
8825 of @code{aloop} filter.
8831 Apply a 3D LUT to an input video.
8833 The filter accepts the following options:
8837 Set the 3D LUT file name.
8839 Currently supported formats:
8851 Select interpolation mode.
8853 Available values are:
8857 Use values from the nearest defined point.
8859 Interpolate values using the 8 points defining a cube.
8861 Interpolate values using a tetrahedron.
8865 @section lut, lutrgb, lutyuv
8867 Compute a look-up table for binding each pixel component input value
8868 to an output value, and apply it to the input video.
8870 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
8871 to an RGB input video.
8873 These filters accept the following parameters:
8876 set first pixel component expression
8878 set second pixel component expression
8880 set third pixel component expression
8882 set fourth pixel component expression, corresponds to the alpha component
8885 set red component expression
8887 set green component expression
8889 set blue component expression
8891 alpha component expression
8894 set Y/luminance component expression
8896 set U/Cb component expression
8898 set V/Cr component expression
8901 Each of them specifies the expression to use for computing the lookup table for
8902 the corresponding pixel component values.
8904 The exact component associated to each of the @var{c*} options depends on the
8907 The @var{lut} filter requires either YUV or RGB pixel formats in input,
8908 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
8910 The expressions can contain the following constants and functions:
8915 The input width and height.
8918 The input value for the pixel component.
8921 The input value, clipped to the @var{minval}-@var{maxval} range.
8924 The maximum value for the pixel component.
8927 The minimum value for the pixel component.
8930 The negated value for the pixel component value, clipped to the
8931 @var{minval}-@var{maxval} range; it corresponds to the expression
8932 "maxval-clipval+minval".
8935 The computed value in @var{val}, clipped to the
8936 @var{minval}-@var{maxval} range.
8938 @item gammaval(gamma)
8939 The computed gamma correction value of the pixel component value,
8940 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
8942 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
8946 All expressions default to "val".
8948 @subsection Examples
8954 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
8955 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
8958 The above is the same as:
8960 lutrgb="r=negval:g=negval:b=negval"
8961 lutyuv="y=negval:u=negval:v=negval"
8971 Remove chroma components, turning the video into a graytone image:
8973 lutyuv="u=128:v=128"
8977 Apply a luma burning effect:
8983 Remove green and blue components:
8989 Set a constant alpha channel value on input:
8991 format=rgba,lutrgb=a="maxval-minval/2"
8995 Correct luminance gamma by a factor of 0.5:
8997 lutyuv=y=gammaval(0.5)
9001 Discard least significant bits of luma:
9003 lutyuv=y='bitand(val, 128+64+32)'
9007 @section maskedmerge
9009 Merge the first input stream with the second input stream using per pixel
9010 weights in the third input stream.
9012 A value of 0 in the third stream pixel component means that pixel component
9013 from first stream is returned unchanged, while maximum value (eg. 255 for
9014 8-bit videos) means that pixel component from second stream is returned
9015 unchanged. Intermediate values define the amount of merging between both
9016 input stream's pixel components.
9018 This filter accepts the following options:
9021 Set which planes will be processed as bitmap, unprocessed planes will be
9022 copied from first stream.
9023 By default value 0xf, all planes will be processed.
9028 Apply motion-compensation deinterlacing.
9030 It needs one field per frame as input and must thus be used together
9031 with yadif=1/3 or equivalent.
9033 This filter accepts the following options:
9036 Set the deinterlacing mode.
9038 It accepts one of the following values:
9043 use iterative motion estimation
9045 like @samp{slow}, but use multiple reference frames.
9047 Default value is @samp{fast}.
9050 Set the picture field parity assumed for the input video. It must be
9051 one of the following values:
9055 assume top field first
9057 assume bottom field first
9060 Default value is @samp{bff}.
9063 Set per-block quantization parameter (QP) used by the internal
9066 Higher values should result in a smoother motion vector field but less
9067 optimal individual vectors. Default value is 1.
9070 @section mergeplanes
9072 Merge color channel components from several video streams.
9074 The filter accepts up to 4 input streams, and merge selected input
9075 planes to the output video.
9077 This filter accepts the following options:
9080 Set input to output plane mapping. Default is @code{0}.
9082 The mappings is specified as a bitmap. It should be specified as a
9083 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
9084 mapping for the first plane of the output stream. 'A' sets the number of
9085 the input stream to use (from 0 to 3), and 'a' the plane number of the
9086 corresponding input to use (from 0 to 3). The rest of the mappings is
9087 similar, 'Bb' describes the mapping for the output stream second
9088 plane, 'Cc' describes the mapping for the output stream third plane and
9089 'Dd' describes the mapping for the output stream fourth plane.
9092 Set output pixel format. Default is @code{yuva444p}.
9095 @subsection Examples
9099 Merge three gray video streams of same width and height into single video stream:
9101 [a0][a1][a2]mergeplanes=0x001020:yuv444p
9105 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
9107 [a0][a1]mergeplanes=0x00010210:yuva444p
9111 Swap Y and A plane in yuva444p stream:
9113 format=yuva444p,mergeplanes=0x03010200:yuva444p
9117 Swap U and V plane in yuv420p stream:
9119 format=yuv420p,mergeplanes=0x000201:yuv420p
9123 Cast a rgb24 clip to yuv444p:
9125 format=rgb24,mergeplanes=0x000102:yuv444p
9129 @section metadata, ametadata
9131 Manipulate frame metadata.
9133 This filter accepts the following options:
9137 Set mode of operation of the filter.
9139 Can be one of the following:
9143 If both @code{value} and @code{key} is set, select frames
9144 which have such metadata. If only @code{key} is set, select
9145 every frame that has such key in metadata.
9148 Add new metadata @code{key} and @code{value}. If key is already available
9152 Modify value of already present key.
9155 If @code{value} is set, delete only keys that have such value.
9156 Otherwise, delete key.
9159 Print key and its value if metadata was found. If @code{key} is not set print all
9160 metadata values available in frame.
9164 Set key used with all modes. Must be set for all modes except @code{print}.
9167 Set metadata value which will be used. This option is mandatory for
9168 @code{modify} and @code{add} mode.
9171 Which function to use when comparing metadata value and @code{value}.
9173 Can be one of following:
9177 Values are interpreted as strings, returns true if metadata value is same as @code{value}.
9180 Values are interpreted as strings, returns true if metadata value starts with
9181 the @code{value} option string.
9184 Values are interpreted as floats, returns true if metadata value is less than @code{value}.
9187 Values are interpreted as floats, returns true if @code{value} is equal with metadata value.
9190 Values are interpreted as floats, returns true if metadata value is greater than @code{value}.
9193 Values are interpreted as floats, returns true if expression from option @code{expr}
9198 Set expression which is used when @code{function} is set to @code{expr}.
9199 The expression is evaluated through the eval API and can contain the following
9204 Float representation of @code{value} from metadata key.
9207 Float representation of @code{value} as supplied by user in @code{value} option.
9211 If specified in @code{print} mode, output is written to the named file. When
9212 filename equals "-" data is written to standard output.
9213 If @code{file} option is not set, output is written to the log with AV_LOG_INFO
9217 @subsection Examples
9221 Print all metadata values for frames with key @code{lavfi.singnalstats.YDIF} with values
9225 signalstats,metadata=print:key=lavfi.signalstats.YDIF:value=0:function=expr:expr='between(VALUE1,0,1)'
9230 Drop frames that do not differ greatly from the previous frame in
9231 order to reduce frame rate.
9233 The main use of this filter is for very-low-bitrate encoding
9234 (e.g. streaming over dialup modem), but it could in theory be used for
9235 fixing movies that were inverse-telecined incorrectly.
9237 A description of the accepted options follows.
9241 Set the maximum number of consecutive frames which can be dropped (if
9242 positive), or the minimum interval between dropped frames (if
9243 negative). If the value is 0, the frame is dropped unregarding the
9244 number of previous sequentially dropped frames.
9251 Set the dropping threshold values.
9253 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
9254 represent actual pixel value differences, so a threshold of 64
9255 corresponds to 1 unit of difference for each pixel, or the same spread
9256 out differently over the block.
9258 A frame is a candidate for dropping if no 8x8 blocks differ by more
9259 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
9260 meaning the whole image) differ by more than a threshold of @option{lo}.
9262 Default value for @option{hi} is 64*12, default value for @option{lo} is
9263 64*5, and default value for @option{frac} is 0.33.
9271 It accepts an integer in input; if non-zero it negates the
9272 alpha component (if available). The default value in input is 0.
9276 Deinterlace video using neural network edge directed interpolation.
9278 This filter accepts the following options:
9282 Mandatory option, without binary file filter can not work.
9283 Currently file can be found here:
9284 https://github.com/dubhater/vapoursynth-nnedi3/blob/master/src/nnedi3_weights.bin
9287 Set which frames to deinterlace, by default it is @code{all}.
9288 Can be @code{all} or @code{interlaced}.
9291 Set mode of operation.
9293 Can be one of the following:
9297 Use frame flags, both fields.
9299 Use frame flags, single field.
9303 Use bottom field only.
9305 Use both fields, top first.
9307 Use both fields, bottom first.
9311 Set which planes to process, by default filter process all frames.
9314 Set size of local neighborhood around each pixel, used by the predictor neural
9317 Can be one of the following:
9330 Set the number of neurons in predicctor neural network.
9331 Can be one of the following:
9342 Controls the number of different neural network predictions that are blended
9343 together to compute the final output value. Can be @code{fast}, default or
9347 Set which set of weights to use in the predictor.
9348 Can be one of the following:
9352 weights trained to minimize absolute error
9354 weights trained to minimize squared error
9358 Controls whether or not the prescreener neural network is used to decide
9359 which pixels should be processed by the predictor neural network and which
9360 can be handled by simple cubic interpolation.
9361 The prescreener is trained to know whether cubic interpolation will be
9362 sufficient for a pixel or whether it should be predicted by the predictor nn.
9363 The computational complexity of the prescreener nn is much less than that of
9364 the predictor nn. Since most pixels can be handled by cubic interpolation,
9365 using the prescreener generally results in much faster processing.
9366 The prescreener is pretty accurate, so the difference between using it and not
9367 using it is almost always unnoticeable.
9369 Can be one of the following:
9377 Default is @code{new}.
9380 Set various debugging flags.
9385 Force libavfilter not to use any of the specified pixel formats for the
9386 input to the next filter.
9388 It accepts the following parameters:
9392 A '|'-separated list of pixel format names, such as
9393 apix_fmts=yuv420p|monow|rgb24".
9397 @subsection Examples
9401 Force libavfilter to use a format different from @var{yuv420p} for the
9402 input to the vflip filter:
9404 noformat=pix_fmts=yuv420p,vflip
9408 Convert the input video to any of the formats not contained in the list:
9410 noformat=yuv420p|yuv444p|yuv410p
9416 Add noise on video input frame.
9418 The filter accepts the following options:
9426 Set noise seed for specific pixel component or all pixel components in case
9427 of @var{all_seed}. Default value is @code{123457}.
9429 @item all_strength, alls
9430 @item c0_strength, c0s
9431 @item c1_strength, c1s
9432 @item c2_strength, c2s
9433 @item c3_strength, c3s
9434 Set noise strength for specific pixel component or all pixel components in case
9435 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
9437 @item all_flags, allf
9442 Set pixel component flags or set flags for all components if @var{all_flags}.
9443 Available values for component flags are:
9446 averaged temporal noise (smoother)
9448 mix random noise with a (semi)regular pattern
9450 temporal noise (noise pattern changes between frames)
9452 uniform noise (gaussian otherwise)
9456 @subsection Examples
9458 Add temporal and uniform noise to input video:
9460 noise=alls=20:allf=t+u
9465 Pass the video source unchanged to the output.
9468 Optical Character Recognition
9470 This filter uses Tesseract for optical character recognition.
9472 It accepts the following options:
9476 Set datapath to tesseract data. Default is to use whatever was
9477 set at installation.
9480 Set language, default is "eng".
9483 Set character whitelist.
9486 Set character blacklist.
9489 The filter exports recognized text as the frame metadata @code{lavfi.ocr.text}.
9493 Apply a video transform using libopencv.
9495 To enable this filter, install the libopencv library and headers and
9496 configure FFmpeg with @code{--enable-libopencv}.
9498 It accepts the following parameters:
9503 The name of the libopencv filter to apply.
9506 The parameters to pass to the libopencv filter. If not specified, the default
9511 Refer to the official libopencv documentation for more precise
9513 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
9515 Several libopencv filters are supported; see the following subsections.
9520 Dilate an image by using a specific structuring element.
9521 It corresponds to the libopencv function @code{cvDilate}.
9523 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
9525 @var{struct_el} represents a structuring element, and has the syntax:
9526 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
9528 @var{cols} and @var{rows} represent the number of columns and rows of
9529 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
9530 point, and @var{shape} the shape for the structuring element. @var{shape}
9531 must be "rect", "cross", "ellipse", or "custom".
9533 If the value for @var{shape} is "custom", it must be followed by a
9534 string of the form "=@var{filename}". The file with name
9535 @var{filename} is assumed to represent a binary image, with each
9536 printable character corresponding to a bright pixel. When a custom
9537 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
9538 or columns and rows of the read file are assumed instead.
9540 The default value for @var{struct_el} is "3x3+0x0/rect".
9542 @var{nb_iterations} specifies the number of times the transform is
9543 applied to the image, and defaults to 1.
9547 # Use the default values
9550 # Dilate using a structuring element with a 5x5 cross, iterating two times
9551 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
9553 # Read the shape from the file diamond.shape, iterating two times.
9554 # The file diamond.shape may contain a pattern of characters like this
9560 # The specified columns and rows are ignored
9561 # but the anchor point coordinates are not
9562 ocv=dilate:0x0+2x2/custom=diamond.shape|2
9567 Erode an image by using a specific structuring element.
9568 It corresponds to the libopencv function @code{cvErode}.
9570 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
9571 with the same syntax and semantics as the @ref{dilate} filter.
9575 Smooth the input video.
9577 The filter takes the following parameters:
9578 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
9580 @var{type} is the type of smooth filter to apply, and must be one of
9581 the following values: "blur", "blur_no_scale", "median", "gaussian",
9582 or "bilateral". The default value is "gaussian".
9584 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
9585 depend on the smooth type. @var{param1} and
9586 @var{param2} accept integer positive values or 0. @var{param3} and
9587 @var{param4} accept floating point values.
9589 The default value for @var{param1} is 3. The default value for the
9590 other parameters is 0.
9592 These parameters correspond to the parameters assigned to the
9593 libopencv function @code{cvSmooth}.
9598 Overlay one video on top of another.
9600 It takes two inputs and has one output. The first input is the "main"
9601 video on which the second input is overlaid.
9603 It accepts the following parameters:
9605 A description of the accepted options follows.
9610 Set the expression for the x and y coordinates of the overlaid video
9611 on the main video. Default value is "0" for both expressions. In case
9612 the expression is invalid, it is set to a huge value (meaning that the
9613 overlay will not be displayed within the output visible area).
9616 The action to take when EOF is encountered on the secondary input; it accepts
9617 one of the following values:
9621 Repeat the last frame (the default).
9625 Pass the main input through.
9629 Set when the expressions for @option{x}, and @option{y} are evaluated.
9631 It accepts the following values:
9634 only evaluate expressions once during the filter initialization or
9635 when a command is processed
9638 evaluate expressions for each incoming frame
9641 Default value is @samp{frame}.
9644 If set to 1, force the output to terminate when the shortest input
9645 terminates. Default value is 0.
9648 Set the format for the output video.
9650 It accepts the following values:
9665 Default value is @samp{yuv420}.
9667 @item rgb @emph{(deprecated)}
9668 If set to 1, force the filter to accept inputs in the RGB
9669 color space. Default value is 0. This option is deprecated, use
9670 @option{format} instead.
9673 If set to 1, force the filter to draw the last overlay frame over the
9674 main input until the end of the stream. A value of 0 disables this
9675 behavior. Default value is 1.
9678 The @option{x}, and @option{y} expressions can contain the following
9684 The main input width and height.
9688 The overlay input width and height.
9692 The computed values for @var{x} and @var{y}. They are evaluated for
9697 horizontal and vertical chroma subsample values of the output
9698 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
9702 the number of input frame, starting from 0
9705 the position in the file of the input frame, NAN if unknown
9708 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
9712 Note that the @var{n}, @var{pos}, @var{t} variables are available only
9713 when evaluation is done @emph{per frame}, and will evaluate to NAN
9714 when @option{eval} is set to @samp{init}.
9716 Be aware that frames are taken from each input video in timestamp
9717 order, hence, if their initial timestamps differ, it is a good idea
9718 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
9719 have them begin in the same zero timestamp, as the example for
9720 the @var{movie} filter does.
9722 You can chain together more overlays but you should test the
9723 efficiency of such approach.
9725 @subsection Commands
9727 This filter supports the following commands:
9731 Modify the x and y of the overlay input.
9732 The command accepts the same syntax of the corresponding option.
9734 If the specified expression is not valid, it is kept at its current
9738 @subsection Examples
9742 Draw the overlay at 10 pixels from the bottom right corner of the main
9745 overlay=main_w-overlay_w-10:main_h-overlay_h-10
9748 Using named options the example above becomes:
9750 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
9754 Insert a transparent PNG logo in the bottom left corner of the input,
9755 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
9757 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
9761 Insert 2 different transparent PNG logos (second logo on bottom
9762 right corner) using the @command{ffmpeg} tool:
9764 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
9768 Add a transparent color layer on top of the main video; @code{WxH}
9769 must specify the size of the main input to the overlay filter:
9771 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
9775 Play an original video and a filtered version (here with the deshake
9776 filter) side by side using the @command{ffplay} tool:
9778 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
9781 The above command is the same as:
9783 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
9787 Make a sliding overlay appearing from the left to the right top part of the
9788 screen starting since time 2:
9790 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
9794 Compose output by putting two input videos side to side:
9796 ffmpeg -i left.avi -i right.avi -filter_complex "
9797 nullsrc=size=200x100 [background];
9798 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
9799 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
9800 [background][left] overlay=shortest=1 [background+left];
9801 [background+left][right] overlay=shortest=1:x=100 [left+right]
9806 Mask 10-20 seconds of a video by applying the delogo filter to a section
9808 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
9809 -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]'
9814 Chain several overlays in cascade:
9816 nullsrc=s=200x200 [bg];
9817 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
9818 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
9819 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
9820 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
9821 [in3] null, [mid2] overlay=100:100 [out0]
9828 Apply Overcomplete Wavelet denoiser.
9830 The filter accepts the following options:
9836 Larger depth values will denoise lower frequency components more, but
9837 slow down filtering.
9839 Must be an int in the range 8-16, default is @code{8}.
9841 @item luma_strength, ls
9844 Must be a double value in the range 0-1000, default is @code{1.0}.
9846 @item chroma_strength, cs
9847 Set chroma strength.
9849 Must be a double value in the range 0-1000, default is @code{1.0}.
9855 Add paddings to the input image, and place the original input at the
9856 provided @var{x}, @var{y} coordinates.
9858 It accepts the following parameters:
9863 Specify an expression for the size of the output image with the
9864 paddings added. If the value for @var{width} or @var{height} is 0, the
9865 corresponding input size is used for the output.
9867 The @var{width} expression can reference the value set by the
9868 @var{height} expression, and vice versa.
9870 The default value of @var{width} and @var{height} is 0.
9874 Specify the offsets to place the input image at within the padded area,
9875 with respect to the top/left border of the output image.
9877 The @var{x} expression can reference the value set by the @var{y}
9878 expression, and vice versa.
9880 The default value of @var{x} and @var{y} is 0.
9883 Specify the color of the padded area. For the syntax of this option,
9884 check the "Color" section in the ffmpeg-utils manual.
9886 The default value of @var{color} is "black".
9889 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
9890 options are expressions containing the following constants:
9895 The input video width and height.
9899 These are the same as @var{in_w} and @var{in_h}.
9903 The output width and height (the size of the padded area), as
9904 specified by the @var{width} and @var{height} expressions.
9908 These are the same as @var{out_w} and @var{out_h}.
9912 The x and y offsets as specified by the @var{x} and @var{y}
9913 expressions, or NAN if not yet specified.
9916 same as @var{iw} / @var{ih}
9919 input sample aspect ratio
9922 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
9926 The horizontal and vertical chroma subsample values. For example for the
9927 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9930 @subsection Examples
9934 Add paddings with the color "violet" to the input video. The output video
9935 size is 640x480, and the top-left corner of the input video is placed at
9938 pad=640:480:0:40:violet
9941 The example above is equivalent to the following command:
9943 pad=width=640:height=480:x=0:y=40:color=violet
9947 Pad the input to get an output with dimensions increased by 3/2,
9948 and put the input video at the center of the padded area:
9950 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
9954 Pad the input to get a squared output with size equal to the maximum
9955 value between the input width and height, and put the input video at
9956 the center of the padded area:
9958 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
9962 Pad the input to get a final w/h ratio of 16:9:
9964 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
9968 In case of anamorphic video, in order to set the output display aspect
9969 correctly, it is necessary to use @var{sar} in the expression,
9970 according to the relation:
9972 (ih * X / ih) * sar = output_dar
9973 X = output_dar / sar
9976 Thus the previous example needs to be modified to:
9978 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
9982 Double the output size and put the input video in the bottom-right
9983 corner of the output padded area:
9985 pad="2*iw:2*ih:ow-iw:oh-ih"
9992 Generate one palette for a whole video stream.
9994 It accepts the following options:
9998 Set the maximum number of colors to quantize in the palette.
9999 Note: the palette will still contain 256 colors; the unused palette entries
10002 @item reserve_transparent
10003 Create a palette of 255 colors maximum and reserve the last one for
10004 transparency. Reserving the transparency color is useful for GIF optimization.
10005 If not set, the maximum of colors in the palette will be 256. You probably want
10006 to disable this option for a standalone image.
10010 Set statistics mode.
10012 It accepts the following values:
10015 Compute full frame histograms.
10017 Compute histograms only for the part that differs from previous frame. This
10018 might be relevant to give more importance to the moving part of your input if
10019 the background is static.
10022 Default value is @var{full}.
10025 The filter also exports the frame metadata @code{lavfi.color_quant_ratio}
10026 (@code{nb_color_in / nb_color_out}) which you can use to evaluate the degree of
10027 color quantization of the palette. This information is also visible at
10028 @var{info} logging level.
10030 @subsection Examples
10034 Generate a representative palette of a given video using @command{ffmpeg}:
10036 ffmpeg -i input.mkv -vf palettegen palette.png
10040 @section paletteuse
10042 Use a palette to downsample an input video stream.
10044 The filter takes two inputs: one video stream and a palette. The palette must
10045 be a 256 pixels image.
10047 It accepts the following options:
10051 Select dithering mode. Available algorithms are:
10054 Ordered 8x8 bayer dithering (deterministic)
10056 Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
10057 Note: this dithering is sometimes considered "wrong" and is included as a
10059 @item floyd_steinberg
10060 Floyd and Steingberg dithering (error diffusion)
10062 Frankie Sierra dithering v2 (error diffusion)
10064 Frankie Sierra dithering v2 "Lite" (error diffusion)
10067 Default is @var{sierra2_4a}.
10070 When @var{bayer} dithering is selected, this option defines the scale of the
10071 pattern (how much the crosshatch pattern is visible). A low value means more
10072 visible pattern for less banding, and higher value means less visible pattern
10073 at the cost of more banding.
10075 The option must be an integer value in the range [0,5]. Default is @var{2}.
10078 If set, define the zone to process
10082 Only the changing rectangle will be reprocessed. This is similar to GIF
10083 cropping/offsetting compression mechanism. This option can be useful for speed
10084 if only a part of the image is changing, and has use cases such as limiting the
10085 scope of the error diffusal @option{dither} to the rectangle that bounds the
10086 moving scene (it leads to more deterministic output if the scene doesn't change
10087 much, and as a result less moving noise and better GIF compression).
10090 Default is @var{none}.
10093 @subsection Examples
10097 Use a palette (generated for example with @ref{palettegen}) to encode a GIF
10098 using @command{ffmpeg}:
10100 ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
10104 @section perspective
10106 Correct perspective of video not recorded perpendicular to the screen.
10108 A description of the accepted parameters follows.
10119 Set coordinates expression for top left, top right, bottom left and bottom right corners.
10120 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
10121 If the @code{sense} option is set to @code{source}, then the specified points will be sent
10122 to the corners of the destination. If the @code{sense} option is set to @code{destination},
10123 then the corners of the source will be sent to the specified coordinates.
10125 The expressions can use the following variables:
10130 the width and height of video frame.
10133 @item interpolation
10134 Set interpolation for perspective correction.
10136 It accepts the following values:
10142 Default value is @samp{linear}.
10145 Set interpretation of coordinate options.
10147 It accepts the following values:
10151 Send point in the source specified by the given coordinates to
10152 the corners of the destination.
10154 @item 1, destination
10156 Send the corners of the source to the point in the destination specified
10157 by the given coordinates.
10159 Default value is @samp{source}.
10165 Delay interlaced video by one field time so that the field order changes.
10167 The intended use is to fix PAL movies that have been captured with the
10168 opposite field order to the film-to-video transfer.
10170 A description of the accepted parameters follows.
10176 It accepts the following values:
10179 Capture field order top-first, transfer bottom-first.
10180 Filter will delay the bottom field.
10183 Capture field order bottom-first, transfer top-first.
10184 Filter will delay the top field.
10187 Capture and transfer with the same field order. This mode only exists
10188 for the documentation of the other options to refer to, but if you
10189 actually select it, the filter will faithfully do nothing.
10192 Capture field order determined automatically by field flags, transfer
10194 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
10195 basis using field flags. If no field information is available,
10196 then this works just like @samp{u}.
10199 Capture unknown or varying, transfer opposite.
10200 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
10201 analyzing the images and selecting the alternative that produces best
10202 match between the fields.
10205 Capture top-first, transfer unknown or varying.
10206 Filter selects among @samp{t} and @samp{p} using image analysis.
10209 Capture bottom-first, transfer unknown or varying.
10210 Filter selects among @samp{b} and @samp{p} using image analysis.
10213 Capture determined by field flags, transfer unknown or varying.
10214 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
10215 image analysis. If no field information is available, then this works just
10216 like @samp{U}. This is the default mode.
10219 Both capture and transfer unknown or varying.
10220 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
10224 @section pixdesctest
10226 Pixel format descriptor test filter, mainly useful for internal
10227 testing. The output video should be equal to the input video.
10231 format=monow, pixdesctest
10234 can be used to test the monowhite pixel format descriptor definition.
10238 Enable the specified chain of postprocessing subfilters using libpostproc. This
10239 library should be automatically selected with a GPL build (@code{--enable-gpl}).
10240 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
10241 Each subfilter and some options have a short and a long name that can be used
10242 interchangeably, i.e. dr/dering are the same.
10244 The filters accept the following options:
10248 Set postprocessing subfilters string.
10251 All subfilters share common options to determine their scope:
10255 Honor the quality commands for this subfilter.
10258 Do chrominance filtering, too (default).
10261 Do luminance filtering only (no chrominance).
10264 Do chrominance filtering only (no luminance).
10267 These options can be appended after the subfilter name, separated by a '|'.
10269 Available subfilters are:
10272 @item hb/hdeblock[|difference[|flatness]]
10273 Horizontal deblocking filter
10276 Difference factor where higher values mean more deblocking (default: @code{32}).
10278 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10281 @item vb/vdeblock[|difference[|flatness]]
10282 Vertical deblocking filter
10285 Difference factor where higher values mean more deblocking (default: @code{32}).
10287 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10290 @item ha/hadeblock[|difference[|flatness]]
10291 Accurate horizontal deblocking filter
10294 Difference factor where higher values mean more deblocking (default: @code{32}).
10296 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10299 @item va/vadeblock[|difference[|flatness]]
10300 Accurate vertical deblocking filter
10303 Difference factor where higher values mean more deblocking (default: @code{32}).
10305 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10309 The horizontal and vertical deblocking filters share the difference and
10310 flatness values so you cannot set different horizontal and vertical
10314 @item h1/x1hdeblock
10315 Experimental horizontal deblocking filter
10317 @item v1/x1vdeblock
10318 Experimental vertical deblocking filter
10323 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
10326 larger -> stronger filtering
10328 larger -> stronger filtering
10330 larger -> stronger filtering
10333 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
10336 Stretch luminance to @code{0-255}.
10339 @item lb/linblenddeint
10340 Linear blend deinterlacing filter that deinterlaces the given block by
10341 filtering all lines with a @code{(1 2 1)} filter.
10343 @item li/linipoldeint
10344 Linear interpolating deinterlacing filter that deinterlaces the given block by
10345 linearly interpolating every second line.
10347 @item ci/cubicipoldeint
10348 Cubic interpolating deinterlacing filter deinterlaces the given block by
10349 cubically interpolating every second line.
10351 @item md/mediandeint
10352 Median deinterlacing filter that deinterlaces the given block by applying a
10353 median filter to every second line.
10355 @item fd/ffmpegdeint
10356 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
10357 second line with a @code{(-1 4 2 4 -1)} filter.
10360 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
10361 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
10363 @item fq/forceQuant[|quantizer]
10364 Overrides the quantizer table from the input with the constant quantizer you
10372 Default pp filter combination (@code{hb|a,vb|a,dr|a})
10375 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
10378 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
10381 @subsection Examples
10385 Apply horizontal and vertical deblocking, deringing and automatic
10386 brightness/contrast:
10392 Apply default filters without brightness/contrast correction:
10398 Apply default filters and temporal denoiser:
10400 pp=default/tmpnoise|1|2|3
10404 Apply deblocking on luminance only, and switch vertical deblocking on or off
10405 automatically depending on available CPU time:
10412 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
10413 similar to spp = 6 with 7 point DCT, where only the center sample is
10416 The filter accepts the following options:
10420 Force a constant quantization parameter. It accepts an integer in range
10421 0 to 63. If not set, the filter will use the QP from the video stream
10425 Set thresholding mode. Available modes are:
10429 Set hard thresholding.
10431 Set soft thresholding (better de-ringing effect, but likely blurrier).
10433 Set medium thresholding (good results, default).
10439 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
10440 Ratio) between two input videos.
10442 This filter takes in input two input videos, the first input is
10443 considered the "main" source and is passed unchanged to the
10444 output. The second input is used as a "reference" video for computing
10447 Both video inputs must have the same resolution and pixel format for
10448 this filter to work correctly. Also it assumes that both inputs
10449 have the same number of frames, which are compared one by one.
10451 The obtained average PSNR is printed through the logging system.
10453 The filter stores the accumulated MSE (mean squared error) of each
10454 frame, and at the end of the processing it is averaged across all frames
10455 equally, and the following formula is applied to obtain the PSNR:
10458 PSNR = 10*log10(MAX^2/MSE)
10461 Where MAX is the average of the maximum values of each component of the
10464 The description of the accepted parameters follows.
10467 @item stats_file, f
10468 If specified the filter will use the named file to save the PSNR of
10469 each individual frame. When filename equals "-" the data is sent to
10473 The file printed if @var{stats_file} is selected, contains a sequence of
10474 key/value pairs of the form @var{key}:@var{value} for each compared
10477 A description of each shown parameter follows:
10481 sequential number of the input frame, starting from 1
10484 Mean Square Error pixel-by-pixel average difference of the compared
10485 frames, averaged over all the image components.
10487 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
10488 Mean Square Error pixel-by-pixel average difference of the compared
10489 frames for the component specified by the suffix.
10491 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
10492 Peak Signal to Noise ratio of the compared frames for the component
10493 specified by the suffix.
10498 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
10499 [main][ref] psnr="stats_file=stats.log" [out]
10502 On this example the input file being processed is compared with the
10503 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
10504 is stored in @file{stats.log}.
10509 Pulldown reversal (inverse telecine) filter, capable of handling mixed
10510 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
10513 The pullup filter is designed to take advantage of future context in making
10514 its decisions. This filter is stateless in the sense that it does not lock
10515 onto a pattern to follow, but it instead looks forward to the following
10516 fields in order to identify matches and rebuild progressive frames.
10518 To produce content with an even framerate, insert the fps filter after
10519 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
10520 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
10522 The filter accepts the following options:
10529 These options set the amount of "junk" to ignore at the left, right, top, and
10530 bottom of the image, respectively. Left and right are in units of 8 pixels,
10531 while top and bottom are in units of 2 lines.
10532 The default is 8 pixels on each side.
10535 Set the strict breaks. Setting this option to 1 will reduce the chances of
10536 filter generating an occasional mismatched frame, but it may also cause an
10537 excessive number of frames to be dropped during high motion sequences.
10538 Conversely, setting it to -1 will make filter match fields more easily.
10539 This may help processing of video where there is slight blurring between
10540 the fields, but may also cause there to be interlaced frames in the output.
10541 Default value is @code{0}.
10544 Set the metric plane to use. It accepts the following values:
10550 Use chroma blue plane.
10553 Use chroma red plane.
10556 This option may be set to use chroma plane instead of the default luma plane
10557 for doing filter's computations. This may improve accuracy on very clean
10558 source material, but more likely will decrease accuracy, especially if there
10559 is chroma noise (rainbow effect) or any grayscale video.
10560 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
10561 load and make pullup usable in realtime on slow machines.
10564 For best results (without duplicated frames in the output file) it is
10565 necessary to change the output frame rate. For example, to inverse
10566 telecine NTSC input:
10568 ffmpeg -i input -vf pullup -r 24000/1001 ...
10573 Change video quantization parameters (QP).
10575 The filter accepts the following option:
10579 Set expression for quantization parameter.
10582 The expression is evaluated through the eval API and can contain, among others,
10583 the following constants:
10587 1 if index is not 129, 0 otherwise.
10590 Sequentional index starting from -129 to 128.
10593 @subsection Examples
10597 Some equation like:
10605 Flush video frames from internal cache of frames into a random order.
10606 No frame is discarded.
10607 Inspired by @ref{frei0r} nervous filter.
10611 Set size in number of frames of internal cache, in range from @code{2} to
10612 @code{512}. Default is @code{30}.
10615 Set seed for random number generator, must be an integer included between
10616 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
10617 less than @code{0}, the filter will try to use a good random seed on a
10623 Read vertical interval timecode (VITC) information from the top lines of a
10626 The filter adds frame metadata key @code{lavfi.readvitc.tc_str} with the
10627 timecode value, if a valid timecode has been detected. Further metadata key
10628 @code{lavfi.readvitc.found} is set to 0/1 depending on whether
10629 timecode data has been found or not.
10631 This filter accepts the following options:
10635 Set the maximum number of lines to scan for VITC data. If the value is set to
10636 @code{-1} the full video frame is scanned. Default is @code{45}.
10639 Set the luma threshold for black. Accepts float numbers in the range [0.0,1.0],
10640 default value is @code{0.2}. The value must be equal or less than @code{thr_w}.
10643 Set the luma threshold for white. Accepts float numbers in the range [0.0,1.0],
10644 default value is @code{0.6}. The value must be equal or greater than @code{thr_b}.
10647 @subsection Examples
10651 Detect and draw VITC data onto the video frame; if no valid VITC is detected,
10652 draw @code{--:--:--:--} as a placeholder:
10654 ffmpeg -i input.avi -filter:v 'readvitc,drawtext=fontfile=FreeMono.ttf:text=%@{metadata\\:lavfi.readvitc.tc_str\\:--\\\\\\:--\\\\\\:--\\\\\\:--@}:x=(w-tw)/2:y=400-ascent'
10660 Remap pixels using 2nd: Xmap and 3rd: Ymap input video stream.
10662 Destination pixel at position (X, Y) will be picked from source (x, y) position
10663 where x = Xmap(X, Y) and y = Ymap(X, Y). If mapping values are out of range, zero
10664 value for pixel will be used for destination pixel.
10666 Xmap and Ymap input video streams must be of same dimensions. Output video stream
10667 will have Xmap/Ymap video stream dimensions.
10668 Xmap and Ymap input video streams are 16bit depth, single channel.
10670 @section removegrain
10672 The removegrain filter is a spatial denoiser for progressive video.
10676 Set mode for the first plane.
10679 Set mode for the second plane.
10682 Set mode for the third plane.
10685 Set mode for the fourth plane.
10688 Range of mode is from 0 to 24. Description of each mode follows:
10692 Leave input plane unchanged. Default.
10695 Clips the pixel with the minimum and maximum of the 8 neighbour pixels.
10698 Clips the pixel with the second minimum and maximum of the 8 neighbour pixels.
10701 Clips the pixel with the third minimum and maximum of the 8 neighbour pixels.
10704 Clips the pixel with the fourth minimum and maximum of the 8 neighbour pixels.
10705 This is equivalent to a median filter.
10708 Line-sensitive clipping giving the minimal change.
10711 Line-sensitive clipping, intermediate.
10714 Line-sensitive clipping, intermediate.
10717 Line-sensitive clipping, intermediate.
10720 Line-sensitive clipping on a line where the neighbours pixels are the closest.
10723 Replaces the target pixel with the closest neighbour.
10726 [1 2 1] horizontal and vertical kernel blur.
10732 Bob mode, interpolates top field from the line where the neighbours
10733 pixels are the closest.
10736 Bob mode, interpolates bottom field from the line where the neighbours
10737 pixels are the closest.
10740 Bob mode, interpolates top field. Same as 13 but with a more complicated
10741 interpolation formula.
10744 Bob mode, interpolates bottom field. Same as 14 but with a more complicated
10745 interpolation formula.
10748 Clips the pixel with the minimum and maximum of respectively the maximum and
10749 minimum of each pair of opposite neighbour pixels.
10752 Line-sensitive clipping using opposite neighbours whose greatest distance from
10753 the current pixel is minimal.
10756 Replaces the pixel with the average of its 8 neighbours.
10759 Averages the 9 pixels ([1 1 1] horizontal and vertical blur).
10762 Clips pixels using the averages of opposite neighbour.
10765 Same as mode 21 but simpler and faster.
10768 Small edge and halo removal, but reputed useless.
10774 @section removelogo
10776 Suppress a TV station logo, using an image file to determine which
10777 pixels comprise the logo. It works by filling in the pixels that
10778 comprise the logo with neighboring pixels.
10780 The filter accepts the following options:
10784 Set the filter bitmap file, which can be any image format supported by
10785 libavformat. The width and height of the image file must match those of the
10786 video stream being processed.
10789 Pixels in the provided bitmap image with a value of zero are not
10790 considered part of the logo, non-zero pixels are considered part of
10791 the logo. If you use white (255) for the logo and black (0) for the
10792 rest, you will be safe. For making the filter bitmap, it is
10793 recommended to take a screen capture of a black frame with the logo
10794 visible, and then using a threshold filter followed by the erode
10795 filter once or twice.
10797 If needed, little splotches can be fixed manually. Remember that if
10798 logo pixels are not covered, the filter quality will be much
10799 reduced. Marking too many pixels as part of the logo does not hurt as
10800 much, but it will increase the amount of blurring needed to cover over
10801 the image and will destroy more information than necessary, and extra
10802 pixels will slow things down on a large logo.
10804 @section repeatfields
10806 This filter uses the repeat_field flag from the Video ES headers and hard repeats
10807 fields based on its value.
10809 @section reverse, areverse
10813 Warning: This filter requires memory to buffer the entire clip, so trimming
10816 @subsection Examples
10820 Take the first 5 seconds of a clip, and reverse it.
10828 Rotate video by an arbitrary angle expressed in radians.
10830 The filter accepts the following options:
10832 A description of the optional parameters follows.
10835 Set an expression for the angle by which to rotate the input video
10836 clockwise, expressed as a number of radians. A negative value will
10837 result in a counter-clockwise rotation. By default it is set to "0".
10839 This expression is evaluated for each frame.
10842 Set the output width expression, default value is "iw".
10843 This expression is evaluated just once during configuration.
10846 Set the output height expression, default value is "ih".
10847 This expression is evaluated just once during configuration.
10850 Enable bilinear interpolation if set to 1, a value of 0 disables
10851 it. Default value is 1.
10854 Set the color used to fill the output area not covered by the rotated
10855 image. For the general syntax of this option, check the "Color" section in the
10856 ffmpeg-utils manual. If the special value "none" is selected then no
10857 background is printed (useful for example if the background is never shown).
10859 Default value is "black".
10862 The expressions for the angle and the output size can contain the
10863 following constants and functions:
10867 sequential number of the input frame, starting from 0. It is always NAN
10868 before the first frame is filtered.
10871 time in seconds of the input frame, it is set to 0 when the filter is
10872 configured. It is always NAN before the first frame is filtered.
10876 horizontal and vertical chroma subsample values. For example for the
10877 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
10881 the input video width and height
10885 the output width and height, that is the size of the padded area as
10886 specified by the @var{width} and @var{height} expressions
10890 the minimal width/height required for completely containing the input
10891 video rotated by @var{a} radians.
10893 These are only available when computing the @option{out_w} and
10894 @option{out_h} expressions.
10897 @subsection Examples
10901 Rotate the input by PI/6 radians clockwise:
10907 Rotate the input by PI/6 radians counter-clockwise:
10913 Rotate the input by 45 degrees clockwise:
10919 Apply a constant rotation with period T, starting from an angle of PI/3:
10921 rotate=PI/3+2*PI*t/T
10925 Make the input video rotation oscillating with a period of T
10926 seconds and an amplitude of A radians:
10928 rotate=A*sin(2*PI/T*t)
10932 Rotate the video, output size is chosen so that the whole rotating
10933 input video is always completely contained in the output:
10935 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
10939 Rotate the video, reduce the output size so that no background is ever
10942 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
10946 @subsection Commands
10948 The filter supports the following commands:
10952 Set the angle expression.
10953 The command accepts the same syntax of the corresponding option.
10955 If the specified expression is not valid, it is kept at its current
10961 Apply Shape Adaptive Blur.
10963 The filter accepts the following options:
10966 @item luma_radius, lr
10967 Set luma blur filter strength, must be a value in range 0.1-4.0, default
10968 value is 1.0. A greater value will result in a more blurred image, and
10969 in slower processing.
10971 @item luma_pre_filter_radius, lpfr
10972 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
10975 @item luma_strength, ls
10976 Set luma maximum difference between pixels to still be considered, must
10977 be a value in the 0.1-100.0 range, default value is 1.0.
10979 @item chroma_radius, cr
10980 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
10981 greater value will result in a more blurred image, and in slower
10984 @item chroma_pre_filter_radius, cpfr
10985 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
10987 @item chroma_strength, cs
10988 Set chroma maximum difference between pixels to still be considered,
10989 must be a value in the 0.1-100.0 range.
10992 Each chroma option value, if not explicitly specified, is set to the
10993 corresponding luma option value.
10998 Scale (resize) the input video, using the libswscale library.
11000 The scale filter forces the output display aspect ratio to be the same
11001 of the input, by changing the output sample aspect ratio.
11003 If the input image format is different from the format requested by
11004 the next filter, the scale filter will convert the input to the
11007 @subsection Options
11008 The filter accepts the following options, or any of the options
11009 supported by the libswscale scaler.
11011 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
11012 the complete list of scaler options.
11017 Set the output video dimension expression. Default value is the input
11020 If the value is 0, the input width is used for the output.
11022 If one of the values is -1, the scale filter will use a value that
11023 maintains the aspect ratio of the input image, calculated from the
11024 other specified dimension. If both of them are -1, the input size is
11027 If one of the values is -n with n > 1, the scale filter will also use a value
11028 that maintains the aspect ratio of the input image, calculated from the other
11029 specified dimension. After that it will, however, make sure that the calculated
11030 dimension is divisible by n and adjust the value if necessary.
11032 See below for the list of accepted constants for use in the dimension
11036 Specify when to evaluate @var{width} and @var{height} expression. It accepts the following values:
11040 Only evaluate expressions once during the filter initialization or when a command is processed.
11043 Evaluate expressions for each incoming frame.
11047 Default value is @samp{init}.
11051 Set the interlacing mode. It accepts the following values:
11055 Force interlaced aware scaling.
11058 Do not apply interlaced scaling.
11061 Select interlaced aware scaling depending on whether the source frames
11062 are flagged as interlaced or not.
11065 Default value is @samp{0}.
11068 Set libswscale scaling flags. See
11069 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
11070 complete list of values. If not explicitly specified the filter applies
11074 @item param0, param1
11075 Set libswscale input parameters for scaling algorithms that need them. See
11076 @ref{sws_params,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
11077 complete documentation. If not explicitly specified the filter applies
11083 Set the video size. For the syntax of this option, check the
11084 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11086 @item in_color_matrix
11087 @item out_color_matrix
11088 Set in/output YCbCr color space type.
11090 This allows the autodetected value to be overridden as well as allows forcing
11091 a specific value used for the output and encoder.
11093 If not specified, the color space type depends on the pixel format.
11099 Choose automatically.
11102 Format conforming to International Telecommunication Union (ITU)
11103 Recommendation BT.709.
11106 Set color space conforming to the United States Federal Communications
11107 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
11110 Set color space conforming to:
11114 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
11117 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
11120 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
11125 Set color space conforming to SMPTE ST 240:1999.
11130 Set in/output YCbCr sample range.
11132 This allows the autodetected value to be overridden as well as allows forcing
11133 a specific value used for the output and encoder. If not specified, the
11134 range depends on the pixel format. Possible values:
11138 Choose automatically.
11141 Set full range (0-255 in case of 8-bit luma).
11144 Set "MPEG" range (16-235 in case of 8-bit luma).
11147 @item force_original_aspect_ratio
11148 Enable decreasing or increasing output video width or height if necessary to
11149 keep the original aspect ratio. Possible values:
11153 Scale the video as specified and disable this feature.
11156 The output video dimensions will automatically be decreased if needed.
11159 The output video dimensions will automatically be increased if needed.
11163 One useful instance of this option is that when you know a specific device's
11164 maximum allowed resolution, you can use this to limit the output video to
11165 that, while retaining the aspect ratio. For example, device A allows
11166 1280x720 playback, and your video is 1920x800. Using this option (set it to
11167 decrease) and specifying 1280x720 to the command line makes the output
11170 Please note that this is a different thing than specifying -1 for @option{w}
11171 or @option{h}, you still need to specify the output resolution for this option
11176 The values of the @option{w} and @option{h} options are expressions
11177 containing the following constants:
11182 The input width and height
11186 These are the same as @var{in_w} and @var{in_h}.
11190 The output (scaled) width and height
11194 These are the same as @var{out_w} and @var{out_h}
11197 The same as @var{iw} / @var{ih}
11200 input sample aspect ratio
11203 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
11207 horizontal and vertical input chroma subsample values. For example for the
11208 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11212 horizontal and vertical output chroma subsample values. For example for the
11213 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11216 @subsection Examples
11220 Scale the input video to a size of 200x100
11225 This is equivalent to:
11236 Specify a size abbreviation for the output size:
11241 which can also be written as:
11247 Scale the input to 2x:
11249 scale=w=2*iw:h=2*ih
11253 The above is the same as:
11255 scale=2*in_w:2*in_h
11259 Scale the input to 2x with forced interlaced scaling:
11261 scale=2*iw:2*ih:interl=1
11265 Scale the input to half size:
11267 scale=w=iw/2:h=ih/2
11271 Increase the width, and set the height to the same size:
11277 Seek Greek harmony:
11284 Increase the height, and set the width to 3/2 of the height:
11286 scale=w=3/2*oh:h=3/5*ih
11290 Increase the size, making the size a multiple of the chroma
11293 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
11297 Increase the width to a maximum of 500 pixels,
11298 keeping the same aspect ratio as the input:
11300 scale=w='min(500\, iw*3/2):h=-1'
11304 @subsection Commands
11306 This filter supports the following commands:
11310 Set the output video dimension expression.
11311 The command accepts the same syntax of the corresponding option.
11313 If the specified expression is not valid, it is kept at its current
11319 Scale (resize) the input video, based on a reference video.
11321 See the scale filter for available options, scale2ref supports the same but
11322 uses the reference video instead of the main input as basis.
11324 @subsection Examples
11328 Scale a subtitle stream to match the main video in size before overlaying
11330 'scale2ref[b][a];[a][b]overlay'
11334 @anchor{selectivecolor}
11335 @section selectivecolor
11337 Adjust cyan, magenta, yellow and black (CMYK) to certain ranges of colors (such
11338 as "reds", "yellows", "greens", "cyans", ...). The adjustment range is defined
11339 by the "purity" of the color (that is, how saturated it already is).
11341 This filter is similar to the Adobe Photoshop Selective Color tool.
11343 The filter accepts the following options:
11346 @item correction_method
11347 Select color correction method.
11349 Available values are:
11352 Specified adjustments are applied "as-is" (added/subtracted to original pixel
11355 Specified adjustments are relative to the original component value.
11357 Default is @code{absolute}.
11359 Adjustments for red pixels (pixels where the red component is the maximum)
11361 Adjustments for yellow pixels (pixels where the blue component is the minimum)
11363 Adjustments for green pixels (pixels where the green component is the maximum)
11365 Adjustments for cyan pixels (pixels where the red component is the minimum)
11367 Adjustments for blue pixels (pixels where the blue component is the maximum)
11369 Adjustments for magenta pixels (pixels where the green component is the minimum)
11371 Adjustments for white pixels (pixels where all components are greater than 128)
11373 Adjustments for all pixels except pure black and pure white
11375 Adjustments for black pixels (pixels where all components are lesser than 128)
11377 Specify a Photoshop selective color file (@code{.asv}) to import the settings from.
11380 All the adjustment settings (@option{reds}, @option{yellows}, ...) accept up to
11381 4 space separated floating point adjustment values in the [-1,1] range,
11382 respectively to adjust the amount of cyan, magenta, yellow and black for the
11383 pixels of its range.
11385 @subsection Examples
11389 Increase cyan by 50% and reduce yellow by 33% in every green areas, and
11390 increase magenta by 27% in blue areas:
11392 selectivecolor=greens=.5 0 -.33 0:blues=0 .27
11396 Use a Photoshop selective color preset:
11398 selectivecolor=psfile=MySelectiveColorPresets/Misty.asv
11402 @section separatefields
11404 The @code{separatefields} takes a frame-based video input and splits
11405 each frame into its components fields, producing a new half height clip
11406 with twice the frame rate and twice the frame count.
11408 This filter use field-dominance information in frame to decide which
11409 of each pair of fields to place first in the output.
11410 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
11412 @section setdar, setsar
11414 The @code{setdar} filter sets the Display Aspect Ratio for the filter
11417 This is done by changing the specified Sample (aka Pixel) Aspect
11418 Ratio, according to the following equation:
11420 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
11423 Keep in mind that the @code{setdar} filter does not modify the pixel
11424 dimensions of the video frame. Also, the display aspect ratio set by
11425 this filter may be changed by later filters in the filterchain,
11426 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
11429 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
11430 the filter output video.
11432 Note that as a consequence of the application of this filter, the
11433 output display aspect ratio will change according to the equation
11436 Keep in mind that the sample aspect ratio set by the @code{setsar}
11437 filter may be changed by later filters in the filterchain, e.g. if
11438 another "setsar" or a "setdar" filter is applied.
11440 It accepts the following parameters:
11443 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
11444 Set the aspect ratio used by the filter.
11446 The parameter can be a floating point number string, an expression, or
11447 a string of the form @var{num}:@var{den}, where @var{num} and
11448 @var{den} are the numerator and denominator of the aspect ratio. If
11449 the parameter is not specified, it is assumed the value "0".
11450 In case the form "@var{num}:@var{den}" is used, the @code{:} character
11454 Set the maximum integer value to use for expressing numerator and
11455 denominator when reducing the expressed aspect ratio to a rational.
11456 Default value is @code{100}.
11460 The parameter @var{sar} is an expression containing
11461 the following constants:
11465 These are approximated values for the mathematical constants e
11466 (Euler's number), pi (Greek pi), and phi (the golden ratio).
11469 The input width and height.
11472 These are the same as @var{w} / @var{h}.
11475 The input sample aspect ratio.
11478 The input display aspect ratio. It is the same as
11479 (@var{w} / @var{h}) * @var{sar}.
11482 Horizontal and vertical chroma subsample values. For example, for the
11483 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11486 @subsection Examples
11491 To change the display aspect ratio to 16:9, specify one of the following:
11499 To change the sample aspect ratio to 10:11, specify:
11505 To set a display aspect ratio of 16:9, and specify a maximum integer value of
11506 1000 in the aspect ratio reduction, use the command:
11508 setdar=ratio=16/9:max=1000
11516 Force field for the output video frame.
11518 The @code{setfield} filter marks the interlace type field for the
11519 output frames. It does not change the input frame, but only sets the
11520 corresponding property, which affects how the frame is treated by
11521 following filters (e.g. @code{fieldorder} or @code{yadif}).
11523 The filter accepts the following options:
11528 Available values are:
11532 Keep the same field property.
11535 Mark the frame as bottom-field-first.
11538 Mark the frame as top-field-first.
11541 Mark the frame as progressive.
11547 Show a line containing various information for each input video frame.
11548 The input video is not modified.
11550 The shown line contains a sequence of key/value pairs of the form
11551 @var{key}:@var{value}.
11553 The following values are shown in the output:
11557 The (sequential) number of the input frame, starting from 0.
11560 The Presentation TimeStamp of the input frame, expressed as a number of
11561 time base units. The time base unit depends on the filter input pad.
11564 The Presentation TimeStamp of the input frame, expressed as a number of
11568 The position of the frame in the input stream, or -1 if this information is
11569 unavailable and/or meaningless (for example in case of synthetic video).
11572 The pixel format name.
11575 The sample aspect ratio of the input frame, expressed in the form
11576 @var{num}/@var{den}.
11579 The size of the input frame. For the syntax of this option, check the
11580 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11583 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
11584 for bottom field first).
11587 This is 1 if the frame is a key frame, 0 otherwise.
11590 The picture type of the input frame ("I" for an I-frame, "P" for a
11591 P-frame, "B" for a B-frame, or "?" for an unknown type).
11592 Also refer to the documentation of the @code{AVPictureType} enum and of
11593 the @code{av_get_picture_type_char} function defined in
11594 @file{libavutil/avutil.h}.
11597 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
11599 @item plane_checksum
11600 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
11601 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
11604 @section showpalette
11606 Displays the 256 colors palette of each frame. This filter is only relevant for
11607 @var{pal8} pixel format frames.
11609 It accepts the following option:
11613 Set the size of the box used to represent one palette color entry. Default is
11614 @code{30} (for a @code{30x30} pixel box).
11617 @section shuffleframes
11619 Reorder and/or duplicate video frames.
11621 It accepts the following parameters:
11625 Set the destination indexes of input frames.
11626 This is space or '|' separated list of indexes that maps input frames to output
11627 frames. Number of indexes also sets maximal value that each index may have.
11630 The first frame has the index 0. The default is to keep the input unchanged.
11632 Swap second and third frame of every three frames of the input:
11634 ffmpeg -i INPUT -vf "shuffleframes=0 2 1" OUTPUT
11637 @section shuffleplanes
11639 Reorder and/or duplicate video planes.
11641 It accepts the following parameters:
11646 The index of the input plane to be used as the first output plane.
11649 The index of the input plane to be used as the second output plane.
11652 The index of the input plane to be used as the third output plane.
11655 The index of the input plane to be used as the fourth output plane.
11659 The first plane has the index 0. The default is to keep the input unchanged.
11661 Swap the second and third planes of the input:
11663 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
11666 @anchor{signalstats}
11667 @section signalstats
11668 Evaluate various visual metrics that assist in determining issues associated
11669 with the digitization of analog video media.
11671 By default the filter will log these metadata values:
11675 Display the minimal Y value contained within the input frame. Expressed in
11679 Display the Y value at the 10% percentile within the input frame. Expressed in
11683 Display the average Y value within the input frame. Expressed in range of
11687 Display the Y value at the 90% percentile within the input frame. Expressed in
11691 Display the maximum Y value contained within the input frame. Expressed in
11695 Display the minimal U value contained within the input frame. Expressed in
11699 Display the U value at the 10% percentile within the input frame. Expressed in
11703 Display the average U value within the input frame. Expressed in range of
11707 Display the U value at the 90% percentile within the input frame. Expressed in
11711 Display the maximum U value contained within the input frame. Expressed in
11715 Display the minimal V value contained within the input frame. Expressed in
11719 Display the V value at the 10% percentile within the input frame. Expressed in
11723 Display the average V value within the input frame. Expressed in range of
11727 Display the V value at the 90% percentile within the input frame. Expressed in
11731 Display the maximum V value contained within the input frame. Expressed in
11735 Display the minimal saturation value contained within the input frame.
11736 Expressed in range of [0-~181.02].
11739 Display the saturation value at the 10% percentile within the input frame.
11740 Expressed in range of [0-~181.02].
11743 Display the average saturation value within the input frame. Expressed in range
11747 Display the saturation value at the 90% percentile within the input frame.
11748 Expressed in range of [0-~181.02].
11751 Display the maximum saturation value contained within the input frame.
11752 Expressed in range of [0-~181.02].
11755 Display the median value for hue within the input frame. Expressed in range of
11759 Display the average value for hue within the input frame. Expressed in range of
11763 Display the average of sample value difference between all values of the Y
11764 plane in the current frame and corresponding values of the previous input frame.
11765 Expressed in range of [0-255].
11768 Display the average of sample value difference between all values of the U
11769 plane in the current frame and corresponding values of the previous input frame.
11770 Expressed in range of [0-255].
11773 Display the average of sample value difference between all values of the V
11774 plane in the current frame and corresponding values of the previous input frame.
11775 Expressed in range of [0-255].
11778 The filter accepts the following options:
11784 @option{stat} specify an additional form of image analysis.
11785 @option{out} output video with the specified type of pixel highlighted.
11787 Both options accept the following values:
11791 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
11792 unlike the neighboring pixels of the same field. Examples of temporal outliers
11793 include the results of video dropouts, head clogs, or tape tracking issues.
11796 Identify @var{vertical line repetition}. Vertical line repetition includes
11797 similar rows of pixels within a frame. In born-digital video vertical line
11798 repetition is common, but this pattern is uncommon in video digitized from an
11799 analog source. When it occurs in video that results from the digitization of an
11800 analog source it can indicate concealment from a dropout compensator.
11803 Identify pixels that fall outside of legal broadcast range.
11807 Set the highlight color for the @option{out} option. The default color is
11811 @subsection Examples
11815 Output data of various video metrics:
11817 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
11821 Output specific data about the minimum and maximum values of the Y plane per frame:
11823 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
11827 Playback video while highlighting pixels that are outside of broadcast range in red.
11829 ffplay example.mov -vf signalstats="out=brng:color=red"
11833 Playback video with signalstats metadata drawn over the frame.
11835 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
11838 The contents of signalstat_drawtext.txt used in the command are:
11841 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
11842 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
11843 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
11844 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
11852 Blur the input video without impacting the outlines.
11854 It accepts the following options:
11857 @item luma_radius, lr
11858 Set the luma radius. The option value must be a float number in
11859 the range [0.1,5.0] that specifies the variance of the gaussian filter
11860 used to blur the image (slower if larger). Default value is 1.0.
11862 @item luma_strength, ls
11863 Set the luma strength. The option value must be a float number
11864 in the range [-1.0,1.0] that configures the blurring. A value included
11865 in [0.0,1.0] will blur the image whereas a value included in
11866 [-1.0,0.0] will sharpen the image. Default value is 1.0.
11868 @item luma_threshold, lt
11869 Set the luma threshold used as a coefficient to determine
11870 whether a pixel should be blurred or not. The option value must be an
11871 integer in the range [-30,30]. A value of 0 will filter all the image,
11872 a value included in [0,30] will filter flat areas and a value included
11873 in [-30,0] will filter edges. Default value is 0.
11875 @item chroma_radius, cr
11876 Set the chroma radius. The option value must be a float number in
11877 the range [0.1,5.0] that specifies the variance of the gaussian filter
11878 used to blur the image (slower if larger). Default value is 1.0.
11880 @item chroma_strength, cs
11881 Set the chroma strength. The option value must be a float number
11882 in the range [-1.0,1.0] that configures the blurring. A value included
11883 in [0.0,1.0] will blur the image whereas a value included in
11884 [-1.0,0.0] will sharpen the image. Default value is 1.0.
11886 @item chroma_threshold, ct
11887 Set the chroma threshold used as a coefficient to determine
11888 whether a pixel should be blurred or not. The option value must be an
11889 integer in the range [-30,30]. A value of 0 will filter all the image,
11890 a value included in [0,30] will filter flat areas and a value included
11891 in [-30,0] will filter edges. Default value is 0.
11894 If a chroma option is not explicitly set, the corresponding luma value
11899 Obtain the SSIM (Structural SImilarity Metric) between two input videos.
11901 This filter takes in input two input videos, the first input is
11902 considered the "main" source and is passed unchanged to the
11903 output. The second input is used as a "reference" video for computing
11906 Both video inputs must have the same resolution and pixel format for
11907 this filter to work correctly. Also it assumes that both inputs
11908 have the same number of frames, which are compared one by one.
11910 The filter stores the calculated SSIM of each frame.
11912 The description of the accepted parameters follows.
11915 @item stats_file, f
11916 If specified the filter will use the named file to save the SSIM of
11917 each individual frame. When filename equals "-" the data is sent to
11921 The file printed if @var{stats_file} is selected, contains a sequence of
11922 key/value pairs of the form @var{key}:@var{value} for each compared
11925 A description of each shown parameter follows:
11929 sequential number of the input frame, starting from 1
11931 @item Y, U, V, R, G, B
11932 SSIM of the compared frames for the component specified by the suffix.
11935 SSIM of the compared frames for the whole frame.
11938 Same as above but in dB representation.
11943 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
11944 [main][ref] ssim="stats_file=stats.log" [out]
11947 On this example the input file being processed is compared with the
11948 reference file @file{ref_movie.mpg}. The SSIM of each individual frame
11949 is stored in @file{stats.log}.
11951 Another example with both psnr and ssim at same time:
11953 ffmpeg -i main.mpg -i ref.mpg -lavfi "ssim;[0:v][1:v]psnr" -f null -
11958 Convert between different stereoscopic image formats.
11960 The filters accept the following options:
11964 Set stereoscopic image format of input.
11966 Available values for input image formats are:
11969 side by side parallel (left eye left, right eye right)
11972 side by side crosseye (right eye left, left eye right)
11975 side by side parallel with half width resolution
11976 (left eye left, right eye right)
11979 side by side crosseye with half width resolution
11980 (right eye left, left eye right)
11983 above-below (left eye above, right eye below)
11986 above-below (right eye above, left eye below)
11989 above-below with half height resolution
11990 (left eye above, right eye below)
11993 above-below with half height resolution
11994 (right eye above, left eye below)
11997 alternating frames (left eye first, right eye second)
12000 alternating frames (right eye first, left eye second)
12003 interleaved rows (left eye has top row, right eye starts on next row)
12006 interleaved rows (right eye has top row, left eye starts on next row)
12009 interleaved columns, left eye first
12012 interleaved columns, right eye first
12014 Default value is @samp{sbsl}.
12018 Set stereoscopic image format of output.
12022 side by side parallel (left eye left, right eye right)
12025 side by side crosseye (right eye left, left eye right)
12028 side by side parallel with half width resolution
12029 (left eye left, right eye right)
12032 side by side crosseye with half width resolution
12033 (right eye left, left eye right)
12036 above-below (left eye above, right eye below)
12039 above-below (right eye above, left eye below)
12042 above-below with half height resolution
12043 (left eye above, right eye below)
12046 above-below with half height resolution
12047 (right eye above, left eye below)
12050 alternating frames (left eye first, right eye second)
12053 alternating frames (right eye first, left eye second)
12056 interleaved rows (left eye has top row, right eye starts on next row)
12059 interleaved rows (right eye has top row, left eye starts on next row)
12062 anaglyph red/blue gray
12063 (red filter on left eye, blue filter on right eye)
12066 anaglyph red/green gray
12067 (red filter on left eye, green filter on right eye)
12070 anaglyph red/cyan gray
12071 (red filter on left eye, cyan filter on right eye)
12074 anaglyph red/cyan half colored
12075 (red filter on left eye, cyan filter on right eye)
12078 anaglyph red/cyan color
12079 (red filter on left eye, cyan filter on right eye)
12082 anaglyph red/cyan color optimized with the least squares projection of dubois
12083 (red filter on left eye, cyan filter on right eye)
12086 anaglyph green/magenta gray
12087 (green filter on left eye, magenta filter on right eye)
12090 anaglyph green/magenta half colored
12091 (green filter on left eye, magenta filter on right eye)
12094 anaglyph green/magenta colored
12095 (green filter on left eye, magenta filter on right eye)
12098 anaglyph green/magenta color optimized with the least squares projection of dubois
12099 (green filter on left eye, magenta filter on right eye)
12102 anaglyph yellow/blue gray
12103 (yellow filter on left eye, blue filter on right eye)
12106 anaglyph yellow/blue half colored
12107 (yellow filter on left eye, blue filter on right eye)
12110 anaglyph yellow/blue colored
12111 (yellow filter on left eye, blue filter on right eye)
12114 anaglyph yellow/blue color optimized with the least squares projection of dubois
12115 (yellow filter on left eye, blue filter on right eye)
12118 mono output (left eye only)
12121 mono output (right eye only)
12124 checkerboard, left eye first
12127 checkerboard, right eye first
12130 interleaved columns, left eye first
12133 interleaved columns, right eye first
12136 Default value is @samp{arcd}.
12139 @subsection Examples
12143 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
12149 Convert input video from above below (left eye above, right eye below) to side by side crosseye.
12155 @section streamselect, astreamselect
12156 Select video or audio streams.
12158 The filter accepts the following options:
12162 Set number of inputs. Default is 2.
12165 Set input indexes to remap to outputs.
12168 @subsection Commands
12170 The @code{streamselect} and @code{astreamselect} filter supports the following
12175 Set input indexes to remap to outputs.
12178 @subsection Examples
12182 Select first 5 seconds 1st stream and rest of time 2nd stream:
12184 sendcmd='5.0 streamselect map 1',streamselect=inputs=2:map=0
12188 Same as above, but for audio:
12190 asendcmd='5.0 astreamselect map 1',astreamselect=inputs=2:map=0
12197 Apply a simple postprocessing filter that compresses and decompresses the image
12198 at several (or - in the case of @option{quality} level @code{6} - all) shifts
12199 and average the results.
12201 The filter accepts the following options:
12205 Set quality. This option defines the number of levels for averaging. It accepts
12206 an integer in the range 0-6. If set to @code{0}, the filter will have no
12207 effect. A value of @code{6} means the higher quality. For each increment of
12208 that value the speed drops by a factor of approximately 2. Default value is
12212 Force a constant quantization parameter. If not set, the filter will use the QP
12213 from the video stream (if available).
12216 Set thresholding mode. Available modes are:
12220 Set hard thresholding (default).
12222 Set soft thresholding (better de-ringing effect, but likely blurrier).
12225 @item use_bframe_qp
12226 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
12227 option may cause flicker since the B-Frames have often larger QP. Default is
12228 @code{0} (not enabled).
12234 Draw subtitles on top of input video using the libass library.
12236 To enable compilation of this filter you need to configure FFmpeg with
12237 @code{--enable-libass}. This filter also requires a build with libavcodec and
12238 libavformat to convert the passed subtitles file to ASS (Advanced Substation
12239 Alpha) subtitles format.
12241 The filter accepts the following options:
12245 Set the filename of the subtitle file to read. It must be specified.
12247 @item original_size
12248 Specify the size of the original video, the video for which the ASS file
12249 was composed. For the syntax of this option, check the
12250 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12251 Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
12252 correctly scale the fonts if the aspect ratio has been changed.
12255 Set a directory path containing fonts that can be used by the filter.
12256 These fonts will be used in addition to whatever the font provider uses.
12259 Set subtitles input character encoding. @code{subtitles} filter only. Only
12260 useful if not UTF-8.
12262 @item stream_index, si
12263 Set subtitles stream index. @code{subtitles} filter only.
12266 Override default style or script info parameters of the subtitles. It accepts a
12267 string containing ASS style format @code{KEY=VALUE} couples separated by ",".
12270 If the first key is not specified, it is assumed that the first value
12271 specifies the @option{filename}.
12273 For example, to render the file @file{sub.srt} on top of the input
12274 video, use the command:
12279 which is equivalent to:
12281 subtitles=filename=sub.srt
12284 To render the default subtitles stream from file @file{video.mkv}, use:
12286 subtitles=video.mkv
12289 To render the second subtitles stream from that file, use:
12291 subtitles=video.mkv:si=1
12294 To make the subtitles stream from @file{sub.srt} appear in transparent green
12295 @code{DejaVu Serif}, use:
12297 subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'
12300 @section super2xsai
12302 Scale the input by 2x and smooth using the Super2xSaI (Scale and
12303 Interpolate) pixel art scaling algorithm.
12305 Useful for enlarging pixel art images without reducing sharpness.
12309 Swap two rectangular objects in video.
12311 This filter accepts the following options:
12321 Set 1st rect x coordinate.
12324 Set 1st rect y coordinate.
12327 Set 2nd rect x coordinate.
12330 Set 2nd rect y coordinate.
12332 All expressions are evaluated once for each frame.
12335 The all options are expressions containing the following constants:
12340 The input width and height.
12343 same as @var{w} / @var{h}
12346 input sample aspect ratio
12349 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
12352 The number of the input frame, starting from 0.
12355 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
12358 the position in the file of the input frame, NAN if unknown
12366 Apply telecine process to the video.
12368 This filter accepts the following options:
12377 The default value is @code{top}.
12381 A string of numbers representing the pulldown pattern you wish to apply.
12382 The default value is @code{23}.
12386 Some typical patterns:
12391 24p: 2332 (preferred)
12398 24p: 222222222223 ("Euro pulldown")
12404 Select the most representative frame in a given sequence of consecutive frames.
12406 The filter accepts the following options:
12410 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
12411 will pick one of them, and then handle the next batch of @var{n} frames until
12412 the end. Default is @code{100}.
12415 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
12416 value will result in a higher memory usage, so a high value is not recommended.
12418 @subsection Examples
12422 Extract one picture each 50 frames:
12428 Complete example of a thumbnail creation with @command{ffmpeg}:
12430 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
12436 Tile several successive frames together.
12438 The filter accepts the following options:
12443 Set the grid size (i.e. the number of lines and columns). For the syntax of
12444 this option, check the
12445 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12448 Set the maximum number of frames to render in the given area. It must be less
12449 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
12450 the area will be used.
12453 Set the outer border margin in pixels.
12456 Set the inner border thickness (i.e. the number of pixels between frames). For
12457 more advanced padding options (such as having different values for the edges),
12458 refer to the pad video filter.
12461 Specify the color of the unused area. For the syntax of this option, check the
12462 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
12466 @subsection Examples
12470 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
12472 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
12474 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
12475 duplicating each output frame to accommodate the originally detected frame
12479 Display @code{5} pictures in an area of @code{3x2} frames,
12480 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
12481 mixed flat and named options:
12483 tile=3x2:nb_frames=5:padding=7:margin=2
12487 @section tinterlace
12489 Perform various types of temporal field interlacing.
12491 Frames are counted starting from 1, so the first input frame is
12494 The filter accepts the following options:
12499 Specify the mode of the interlacing. This option can also be specified
12500 as a value alone. See below for a list of values for this option.
12502 Available values are:
12506 Move odd frames into the upper field, even into the lower field,
12507 generating a double height frame at half frame rate.
12511 Frame 1 Frame 2 Frame 3 Frame 4
12513 11111 22222 33333 44444
12514 11111 22222 33333 44444
12515 11111 22222 33333 44444
12516 11111 22222 33333 44444
12530 Only output even frames, odd frames are dropped, generating a frame with
12531 unchanged height at half frame rate.
12536 Frame 1 Frame 2 Frame 3 Frame 4
12538 11111 22222 33333 44444
12539 11111 22222 33333 44444
12540 11111 22222 33333 44444
12541 11111 22222 33333 44444
12551 Only output odd frames, even frames are dropped, generating a frame with
12552 unchanged height at half frame rate.
12557 Frame 1 Frame 2 Frame 3 Frame 4
12559 11111 22222 33333 44444
12560 11111 22222 33333 44444
12561 11111 22222 33333 44444
12562 11111 22222 33333 44444
12572 Expand each frame to full height, but pad alternate lines with black,
12573 generating a frame with double height at the same input frame rate.
12578 Frame 1 Frame 2 Frame 3 Frame 4
12580 11111 22222 33333 44444
12581 11111 22222 33333 44444
12582 11111 22222 33333 44444
12583 11111 22222 33333 44444
12586 11111 ..... 33333 .....
12587 ..... 22222 ..... 44444
12588 11111 ..... 33333 .....
12589 ..... 22222 ..... 44444
12590 11111 ..... 33333 .....
12591 ..... 22222 ..... 44444
12592 11111 ..... 33333 .....
12593 ..... 22222 ..... 44444
12597 @item interleave_top, 4
12598 Interleave the upper field from odd frames with the lower field from
12599 even frames, generating a frame with unchanged height at half frame rate.
12604 Frame 1 Frame 2 Frame 3 Frame 4
12606 11111<- 22222 33333<- 44444
12607 11111 22222<- 33333 44444<-
12608 11111<- 22222 33333<- 44444
12609 11111 22222<- 33333 44444<-
12619 @item interleave_bottom, 5
12620 Interleave the lower field from odd frames with the upper field from
12621 even frames, generating a frame with unchanged height at half frame rate.
12626 Frame 1 Frame 2 Frame 3 Frame 4
12628 11111 22222<- 33333 44444<-
12629 11111<- 22222 33333<- 44444
12630 11111 22222<- 33333 44444<-
12631 11111<- 22222 33333<- 44444
12641 @item interlacex2, 6
12642 Double frame rate with unchanged height. Frames are inserted each
12643 containing the second temporal field from the previous input frame and
12644 the first temporal field from the next input frame. This mode relies on
12645 the top_field_first flag. Useful for interlaced video displays with no
12646 field synchronisation.
12651 Frame 1 Frame 2 Frame 3 Frame 4
12653 11111 22222 33333 44444
12654 11111 22222 33333 44444
12655 11111 22222 33333 44444
12656 11111 22222 33333 44444
12659 11111 22222 22222 33333 33333 44444 44444
12660 11111 11111 22222 22222 33333 33333 44444
12661 11111 22222 22222 33333 33333 44444 44444
12662 11111 11111 22222 22222 33333 33333 44444
12666 Move odd frames into the upper field, even into the lower field,
12667 generating a double height frame at same frame rate.
12671 Frame 1 Frame 2 Frame 3 Frame 4
12673 11111 22222 33333 44444
12674 11111 22222 33333 44444
12675 11111 22222 33333 44444
12676 11111 22222 33333 44444
12679 11111 33333 33333 55555
12680 22222 22222 44444 44444
12681 11111 33333 33333 55555
12682 22222 22222 44444 44444
12683 11111 33333 33333 55555
12684 22222 22222 44444 44444
12685 11111 33333 33333 55555
12686 22222 22222 44444 44444
12691 Numeric values are deprecated but are accepted for backward
12692 compatibility reasons.
12694 Default mode is @code{merge}.
12697 Specify flags influencing the filter process.
12699 Available value for @var{flags} is:
12702 @item low_pass_filter, vlfp
12703 Enable vertical low-pass filtering in the filter.
12704 Vertical low-pass filtering is required when creating an interlaced
12705 destination from a progressive source which contains high-frequency
12706 vertical detail. Filtering will reduce interlace 'twitter' and Moire
12709 Vertical low-pass filtering can only be enabled for @option{mode}
12710 @var{interleave_top} and @var{interleave_bottom}.
12717 Transpose rows with columns in the input video and optionally flip it.
12719 It accepts the following parameters:
12724 Specify the transposition direction.
12726 Can assume the following values:
12728 @item 0, 4, cclock_flip
12729 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
12737 Rotate by 90 degrees clockwise, that is:
12745 Rotate by 90 degrees counterclockwise, that is:
12752 @item 3, 7, clock_flip
12753 Rotate by 90 degrees clockwise and vertically flip, that is:
12761 For values between 4-7, the transposition is only done if the input
12762 video geometry is portrait and not landscape. These values are
12763 deprecated, the @code{passthrough} option should be used instead.
12765 Numerical values are deprecated, and should be dropped in favor of
12766 symbolic constants.
12769 Do not apply the transposition if the input geometry matches the one
12770 specified by the specified value. It accepts the following values:
12773 Always apply transposition.
12775 Preserve portrait geometry (when @var{height} >= @var{width}).
12777 Preserve landscape geometry (when @var{width} >= @var{height}).
12780 Default value is @code{none}.
12783 For example to rotate by 90 degrees clockwise and preserve portrait
12786 transpose=dir=1:passthrough=portrait
12789 The command above can also be specified as:
12791 transpose=1:portrait
12795 Trim the input so that the output contains one continuous subpart of the input.
12797 It accepts the following parameters:
12800 Specify the time of the start of the kept section, i.e. the frame with the
12801 timestamp @var{start} will be the first frame in the output.
12804 Specify the time of the first frame that will be dropped, i.e. the frame
12805 immediately preceding the one with the timestamp @var{end} will be the last
12806 frame in the output.
12809 This is the same as @var{start}, except this option sets the start timestamp
12810 in timebase units instead of seconds.
12813 This is the same as @var{end}, except this option sets the end timestamp
12814 in timebase units instead of seconds.
12817 The maximum duration of the output in seconds.
12820 The number of the first frame that should be passed to the output.
12823 The number of the first frame that should be dropped.
12826 @option{start}, @option{end}, and @option{duration} are expressed as time
12827 duration specifications; see
12828 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
12829 for the accepted syntax.
12831 Note that the first two sets of the start/end options and the @option{duration}
12832 option look at the frame timestamp, while the _frame variants simply count the
12833 frames that pass through the filter. Also note that this filter does not modify
12834 the timestamps. If you wish for the output timestamps to start at zero, insert a
12835 setpts filter after the trim filter.
12837 If multiple start or end options are set, this filter tries to be greedy and
12838 keep all the frames that match at least one of the specified constraints. To keep
12839 only the part that matches all the constraints at once, chain multiple trim
12842 The defaults are such that all the input is kept. So it is possible to set e.g.
12843 just the end values to keep everything before the specified time.
12848 Drop everything except the second minute of input:
12850 ffmpeg -i INPUT -vf trim=60:120
12854 Keep only the first second:
12856 ffmpeg -i INPUT -vf trim=duration=1
12865 Sharpen or blur the input video.
12867 It accepts the following parameters:
12870 @item luma_msize_x, lx
12871 Set the luma matrix horizontal size. It must be an odd integer between
12872 3 and 63. The default value is 5.
12874 @item luma_msize_y, ly
12875 Set the luma matrix vertical size. It must be an odd integer between 3
12876 and 63. The default value is 5.
12878 @item luma_amount, la
12879 Set the luma effect strength. It must be a floating point number, reasonable
12880 values lay between -1.5 and 1.5.
12882 Negative values will blur the input video, while positive values will
12883 sharpen it, a value of zero will disable the effect.
12885 Default value is 1.0.
12887 @item chroma_msize_x, cx
12888 Set the chroma matrix horizontal size. It must be an odd integer
12889 between 3 and 63. The default value is 5.
12891 @item chroma_msize_y, cy
12892 Set the chroma matrix vertical size. It must be an odd integer
12893 between 3 and 63. The default value is 5.
12895 @item chroma_amount, ca
12896 Set the chroma effect strength. It must be a floating point number, reasonable
12897 values lay between -1.5 and 1.5.
12899 Negative values will blur the input video, while positive values will
12900 sharpen it, a value of zero will disable the effect.
12902 Default value is 0.0.
12905 If set to 1, specify using OpenCL capabilities, only available if
12906 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
12910 All parameters are optional and default to the equivalent of the
12911 string '5:5:1.0:5:5:0.0'.
12913 @subsection Examples
12917 Apply strong luma sharpen effect:
12919 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
12923 Apply a strong blur of both luma and chroma parameters:
12925 unsharp=7:7:-2:7:7:-2
12931 Apply ultra slow/simple postprocessing filter that compresses and decompresses
12932 the image at several (or - in the case of @option{quality} level @code{8} - all)
12933 shifts and average the results.
12935 The way this differs from the behavior of spp is that uspp actually encodes &
12936 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
12937 DCT similar to MJPEG.
12939 The filter accepts the following options:
12943 Set quality. This option defines the number of levels for averaging. It accepts
12944 an integer in the range 0-8. If set to @code{0}, the filter will have no
12945 effect. A value of @code{8} means the higher quality. For each increment of
12946 that value the speed drops by a factor of approximately 2. Default value is
12950 Force a constant quantization parameter. If not set, the filter will use the QP
12951 from the video stream (if available).
12954 @section vectorscope
12956 Display 2 color component values in the two dimensional graph (which is called
12959 This filter accepts the following options:
12963 Set vectorscope mode.
12965 It accepts the following values:
12968 Gray values are displayed on graph, higher brightness means more pixels have
12969 same component color value on location in graph. This is the default mode.
12972 Gray values are displayed on graph. Surrounding pixels values which are not
12973 present in video frame are drawn in gradient of 2 color components which are
12974 set by option @code{x} and @code{y}. The 3rd color component is static.
12977 Actual color components values present in video frame are displayed on graph.
12980 Similar as color2 but higher frequency of same values @code{x} and @code{y}
12981 on graph increases value of another color component, which is luminance by
12982 default values of @code{x} and @code{y}.
12985 Actual colors present in video frame are displayed on graph. If two different
12986 colors map to same position on graph then color with higher value of component
12987 not present in graph is picked.
12990 Gray values are displayed on graph. Similar to @code{color} but with 3rd color
12991 component picked from radial gradient.
12995 Set which color component will be represented on X-axis. Default is @code{1}.
12998 Set which color component will be represented on Y-axis. Default is @code{2}.
13001 Set intensity, used by modes: gray, color, color3 and color5 for increasing brightness
13002 of color component which represents frequency of (X, Y) location in graph.
13007 No envelope, this is default.
13010 Instant envelope, even darkest single pixel will be clearly highlighted.
13013 Hold maximum and minimum values presented in graph over time. This way you
13014 can still spot out of range values without constantly looking at vectorscope.
13017 Peak and instant envelope combined together.
13021 Set what kind of graticule to draw.
13029 Set graticule opacity.
13032 Set graticule flags.
13036 Draw graticule for white point.
13039 Draw graticule for black point.
13042 Draw color points short names.
13046 Set background opacity.
13048 @item lthreshold, l
13049 Set low threshold for color component not represented on X or Y axis.
13050 Values lower than this value will be ignored. Default is 0.
13051 Note this value is multiplied with actual max possible value one pixel component
13052 can have. So for 8-bit input and low threshold value of 0.1 actual threshold
13055 @item hthreshold, h
13056 Set high threshold for color component not represented on X or Y axis.
13057 Values higher than this value will be ignored. Default is 1.
13058 Note this value is multiplied with actual max possible value one pixel component
13059 can have. So for 8-bit input and high threshold value of 0.9 actual threshold
13060 is 0.9 * 255 = 230.
13062 @item colorspace, c
13063 Set what kind of colorspace to use when drawing graticule.
13072 @anchor{vidstabdetect}
13073 @section vidstabdetect
13075 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
13076 @ref{vidstabtransform} for pass 2.
13078 This filter generates a file with relative translation and rotation
13079 transform information about subsequent frames, which is then used by
13080 the @ref{vidstabtransform} filter.
13082 To enable compilation of this filter you need to configure FFmpeg with
13083 @code{--enable-libvidstab}.
13085 This filter accepts the following options:
13089 Set the path to the file used to write the transforms information.
13090 Default value is @file{transforms.trf}.
13093 Set how shaky the video is and how quick the camera is. It accepts an
13094 integer in the range 1-10, a value of 1 means little shakiness, a
13095 value of 10 means strong shakiness. Default value is 5.
13098 Set the accuracy of the detection process. It must be a value in the
13099 range 1-15. A value of 1 means low accuracy, a value of 15 means high
13100 accuracy. Default value is 15.
13103 Set stepsize of the search process. The region around minimum is
13104 scanned with 1 pixel resolution. Default value is 6.
13107 Set minimum contrast. Below this value a local measurement field is
13108 discarded. Must be a floating point value in the range 0-1. Default
13112 Set reference frame number for tripod mode.
13114 If enabled, the motion of the frames is compared to a reference frame
13115 in the filtered stream, identified by the specified number. The idea
13116 is to compensate all movements in a more-or-less static scene and keep
13117 the camera view absolutely still.
13119 If set to 0, it is disabled. The frames are counted starting from 1.
13122 Show fields and transforms in the resulting frames. It accepts an
13123 integer in the range 0-2. Default value is 0, which disables any
13127 @subsection Examples
13131 Use default values:
13137 Analyze strongly shaky movie and put the results in file
13138 @file{mytransforms.trf}:
13140 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
13144 Visualize the result of internal transformations in the resulting
13147 vidstabdetect=show=1
13151 Analyze a video with medium shakiness using @command{ffmpeg}:
13153 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
13157 @anchor{vidstabtransform}
13158 @section vidstabtransform
13160 Video stabilization/deshaking: pass 2 of 2,
13161 see @ref{vidstabdetect} for pass 1.
13163 Read a file with transform information for each frame and
13164 apply/compensate them. Together with the @ref{vidstabdetect}
13165 filter this can be used to deshake videos. See also
13166 @url{http://public.hronopik.de/vid.stab}. It is important to also use
13167 the @ref{unsharp} filter, see below.
13169 To enable compilation of this filter you need to configure FFmpeg with
13170 @code{--enable-libvidstab}.
13172 @subsection Options
13176 Set path to the file used to read the transforms. Default value is
13177 @file{transforms.trf}.
13180 Set the number of frames (value*2 + 1) used for lowpass filtering the
13181 camera movements. Default value is 10.
13183 For example a number of 10 means that 21 frames are used (10 in the
13184 past and 10 in the future) to smoothen the motion in the video. A
13185 larger value leads to a smoother video, but limits the acceleration of
13186 the camera (pan/tilt movements). 0 is a special case where a static
13187 camera is simulated.
13190 Set the camera path optimization algorithm.
13192 Accepted values are:
13195 gaussian kernel low-pass filter on camera motion (default)
13197 averaging on transformations
13201 Set maximal number of pixels to translate frames. Default value is -1,
13205 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
13206 value is -1, meaning no limit.
13209 Specify how to deal with borders that may be visible due to movement
13212 Available values are:
13215 keep image information from previous frame (default)
13217 fill the border black
13221 Invert transforms if set to 1. Default value is 0.
13224 Consider transforms as relative to previous frame if set to 1,
13225 absolute if set to 0. Default value is 0.
13228 Set percentage to zoom. A positive value will result in a zoom-in
13229 effect, a negative value in a zoom-out effect. Default value is 0 (no
13233 Set optimal zooming to avoid borders.
13235 Accepted values are:
13240 optimal static zoom value is determined (only very strong movements
13241 will lead to visible borders) (default)
13243 optimal adaptive zoom value is determined (no borders will be
13244 visible), see @option{zoomspeed}
13247 Note that the value given at zoom is added to the one calculated here.
13250 Set percent to zoom maximally each frame (enabled when
13251 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
13255 Specify type of interpolation.
13257 Available values are:
13262 linear only horizontal
13264 linear in both directions (default)
13266 cubic in both directions (slow)
13270 Enable virtual tripod mode if set to 1, which is equivalent to
13271 @code{relative=0:smoothing=0}. Default value is 0.
13273 Use also @code{tripod} option of @ref{vidstabdetect}.
13276 Increase log verbosity if set to 1. Also the detected global motions
13277 are written to the temporary file @file{global_motions.trf}. Default
13281 @subsection Examples
13285 Use @command{ffmpeg} for a typical stabilization with default values:
13287 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
13290 Note the use of the @ref{unsharp} filter which is always recommended.
13293 Zoom in a bit more and load transform data from a given file:
13295 vidstabtransform=zoom=5:input="mytransforms.trf"
13299 Smoothen the video even more:
13301 vidstabtransform=smoothing=30
13307 Flip the input video vertically.
13309 For example, to vertically flip a video with @command{ffmpeg}:
13311 ffmpeg -i in.avi -vf "vflip" out.avi
13317 Make or reverse a natural vignetting effect.
13319 The filter accepts the following options:
13323 Set lens angle expression as a number of radians.
13325 The value is clipped in the @code{[0,PI/2]} range.
13327 Default value: @code{"PI/5"}
13331 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
13335 Set forward/backward mode.
13337 Available modes are:
13340 The larger the distance from the central point, the darker the image becomes.
13343 The larger the distance from the central point, the brighter the image becomes.
13344 This can be used to reverse a vignette effect, though there is no automatic
13345 detection to extract the lens @option{angle} and other settings (yet). It can
13346 also be used to create a burning effect.
13349 Default value is @samp{forward}.
13352 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
13354 It accepts the following values:
13357 Evaluate expressions only once during the filter initialization.
13360 Evaluate expressions for each incoming frame. This is way slower than the
13361 @samp{init} mode since it requires all the scalers to be re-computed, but it
13362 allows advanced dynamic expressions.
13365 Default value is @samp{init}.
13368 Set dithering to reduce the circular banding effects. Default is @code{1}
13372 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
13373 Setting this value to the SAR of the input will make a rectangular vignetting
13374 following the dimensions of the video.
13376 Default is @code{1/1}.
13379 @subsection Expressions
13381 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
13382 following parameters.
13387 input width and height
13390 the number of input frame, starting from 0
13393 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
13394 @var{TB} units, NAN if undefined
13397 frame rate of the input video, NAN if the input frame rate is unknown
13400 the PTS (Presentation TimeStamp) of the filtered video frame,
13401 expressed in seconds, NAN if undefined
13404 time base of the input video
13408 @subsection Examples
13412 Apply simple strong vignetting effect:
13418 Make a flickering vignetting:
13420 vignette='PI/4+random(1)*PI/50':eval=frame
13426 Stack input videos vertically.
13428 All streams must be of same pixel format and of same width.
13430 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
13431 to create same output.
13433 The filter accept the following option:
13437 Set number of input streams. Default is 2.
13440 If set to 1, force the output to terminate when the shortest input
13441 terminates. Default value is 0.
13446 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
13447 Deinterlacing Filter").
13449 Based on the process described by Martin Weston for BBC R&D, and
13450 implemented based on the de-interlace algorithm written by Jim
13451 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
13452 uses filter coefficients calculated by BBC R&D.
13454 There are two sets of filter coefficients, so called "simple":
13455 and "complex". Which set of filter coefficients is used can
13456 be set by passing an optional parameter:
13460 Set the interlacing filter coefficients. Accepts one of the following values:
13464 Simple filter coefficient set.
13466 More-complex filter coefficient set.
13468 Default value is @samp{complex}.
13471 Specify which frames to deinterlace. Accept one of the following values:
13475 Deinterlace all frames,
13477 Only deinterlace frames marked as interlaced.
13480 Default value is @samp{all}.
13484 Video waveform monitor.
13486 The waveform monitor plots color component intensity. By default luminance
13487 only. Each column of the waveform corresponds to a column of pixels in the
13490 It accepts the following options:
13494 Can be either @code{row}, or @code{column}. Default is @code{column}.
13495 In row mode, the graph on the left side represents color component value 0 and
13496 the right side represents value = 255. In column mode, the top side represents
13497 color component value = 0 and bottom side represents value = 255.
13500 Set intensity. Smaller values are useful to find out how many values of the same
13501 luminance are distributed across input rows/columns.
13502 Default value is @code{0.04}. Allowed range is [0, 1].
13505 Set mirroring mode. @code{0} means unmirrored, @code{1} means mirrored.
13506 In mirrored mode, higher values will be represented on the left
13507 side for @code{row} mode and at the top for @code{column} mode. Default is
13508 @code{1} (mirrored).
13512 It accepts the following values:
13515 Presents information identical to that in the @code{parade}, except
13516 that the graphs representing color components are superimposed directly
13519 This display mode makes it easier to spot relative differences or similarities
13520 in overlapping areas of the color components that are supposed to be identical,
13521 such as neutral whites, grays, or blacks.
13524 Display separate graph for the color components side by side in
13525 @code{row} mode or one below the other in @code{column} mode.
13528 Display separate graph for the color components side by side in
13529 @code{column} mode or one below the other in @code{row} mode.
13531 Using this display mode makes it easy to spot color casts in the highlights
13532 and shadows of an image, by comparing the contours of the top and the bottom
13533 graphs of each waveform. Since whites, grays, and blacks are characterized
13534 by exactly equal amounts of red, green, and blue, neutral areas of the picture
13535 should display three waveforms of roughly equal width/height. If not, the
13536 correction is easy to perform by making level adjustments the three waveforms.
13538 Default is @code{stack}.
13540 @item components, c
13541 Set which color components to display. Default is 1, which means only luminance
13542 or red color component if input is in RGB colorspace. If is set for example to
13543 7 it will display all 3 (if) available color components.
13548 No envelope, this is default.
13551 Instant envelope, minimum and maximum values presented in graph will be easily
13552 visible even with small @code{step} value.
13555 Hold minimum and maximum values presented in graph across time. This way you
13556 can still spot out of range values without constantly looking at waveforms.
13559 Peak and instant envelope combined together.
13565 No filtering, this is default.
13568 Luma and chroma combined together.
13571 Similar as above, but shows difference between blue and red chroma.
13574 Displays only chroma.
13577 Displays actual color value on waveform.
13580 Similar as above, but with luma showing frequency of chroma values.
13584 Set which graticule to display.
13588 Do not display graticule.
13591 Display green graticule showing legal broadcast ranges.
13595 Set graticule opacity.
13598 Set graticule flags.
13602 Draw numbers above lines. By default enabled.
13605 Draw dots instead of lines.
13609 Set scale used for displaying graticule.
13616 Default is digital.
13620 Apply the xBR high-quality magnification filter which is designed for pixel
13621 art. It follows a set of edge-detection rules, see
13622 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
13624 It accepts the following option:
13628 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
13629 @code{3xBR} and @code{4} for @code{4xBR}.
13630 Default is @code{3}.
13636 Deinterlace the input video ("yadif" means "yet another deinterlacing
13639 It accepts the following parameters:
13645 The interlacing mode to adopt. It accepts one of the following values:
13648 @item 0, send_frame
13649 Output one frame for each frame.
13650 @item 1, send_field
13651 Output one frame for each field.
13652 @item 2, send_frame_nospatial
13653 Like @code{send_frame}, but it skips the spatial interlacing check.
13654 @item 3, send_field_nospatial
13655 Like @code{send_field}, but it skips the spatial interlacing check.
13658 The default value is @code{send_frame}.
13661 The picture field parity assumed for the input interlaced video. It accepts one
13662 of the following values:
13666 Assume the top field is first.
13668 Assume the bottom field is first.
13670 Enable automatic detection of field parity.
13673 The default value is @code{auto}.
13674 If the interlacing is unknown or the decoder does not export this information,
13675 top field first will be assumed.
13678 Specify which frames to deinterlace. Accept one of the following
13683 Deinterlace all frames.
13684 @item 1, interlaced
13685 Only deinterlace frames marked as interlaced.
13688 The default value is @code{all}.
13693 Apply Zoom & Pan effect.
13695 This filter accepts the following options:
13699 Set the zoom expression. Default is 1.
13703 Set the x and y expression. Default is 0.
13706 Set the duration expression in number of frames.
13707 This sets for how many number of frames effect will last for
13708 single input image.
13711 Set the output image size, default is 'hd720'.
13714 Set the output frame rate, default is '25'.
13717 Each expression can contain the following constants:
13736 Output frame count.
13740 Last calculated 'x' and 'y' position from 'x' and 'y' expression
13741 for current input frame.
13745 'x' and 'y' of last output frame of previous input frame or 0 when there was
13746 not yet such frame (first input frame).
13749 Last calculated zoom from 'z' expression for current input frame.
13752 Last calculated zoom of last output frame of previous input frame.
13755 Number of output frames for current input frame. Calculated from 'd' expression
13756 for each input frame.
13759 number of output frames created for previous input frame
13762 Rational number: input width / input height
13765 sample aspect ratio
13768 display aspect ratio
13772 @subsection Examples
13776 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
13778 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
13782 Zoom-in up to 1.5 and pan always at center of picture:
13784 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
13789 Scale (resize) the input video, using the z.lib library:
13790 https://github.com/sekrit-twc/zimg.
13792 The zscale filter forces the output display aspect ratio to be the same
13793 as the input, by changing the output sample aspect ratio.
13795 If the input image format is different from the format requested by
13796 the next filter, the zscale filter will convert the input to the
13799 @subsection Options
13800 The filter accepts the following options.
13805 Set the output video dimension expression. Default value is the input
13808 If the @var{width} or @var{w} is 0, the input width is used for the output.
13809 If the @var{height} or @var{h} is 0, the input height is used for the output.
13811 If one of the values is -1, the zscale filter will use a value that
13812 maintains the aspect ratio of the input image, calculated from the
13813 other specified dimension. If both of them are -1, the input size is
13816 If one of the values is -n with n > 1, the zscale filter will also use a value
13817 that maintains the aspect ratio of the input image, calculated from the other
13818 specified dimension. After that it will, however, make sure that the calculated
13819 dimension is divisible by n and adjust the value if necessary.
13821 See below for the list of accepted constants for use in the dimension
13825 Set the video size. For the syntax of this option, check the
13826 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13829 Set the dither type.
13831 Possible values are:
13836 @item error_diffusion
13842 Set the resize filter type.
13844 Possible values are:
13854 Default is bilinear.
13857 Set the color range.
13859 Possible values are:
13866 Default is same as input.
13869 Set the color primaries.
13871 Possible values are:
13881 Default is same as input.
13884 Set the transfer characteristics.
13886 Possible values are:
13897 Default is same as input.
13900 Set the colorspace matrix.
13902 Possible value are:
13913 Default is same as input.
13916 Set the input color range.
13918 Possible values are:
13925 Default is same as input.
13927 @item primariesin, pin
13928 Set the input color primaries.
13930 Possible values are:
13940 Default is same as input.
13942 @item transferin, tin
13943 Set the input transfer characteristics.
13945 Possible values are:
13956 Default is same as input.
13958 @item matrixin, min
13959 Set the input colorspace matrix.
13961 Possible value are:
13973 The values of the @option{w} and @option{h} options are expressions
13974 containing the following constants:
13979 The input width and height
13983 These are the same as @var{in_w} and @var{in_h}.
13987 The output (scaled) width and height
13991 These are the same as @var{out_w} and @var{out_h}
13994 The same as @var{iw} / @var{ih}
13997 input sample aspect ratio
14000 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
14004 horizontal and vertical input chroma subsample values. For example for the
14005 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
14009 horizontal and vertical output chroma subsample values. For example for the
14010 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
14016 @c man end VIDEO FILTERS
14018 @chapter Video Sources
14019 @c man begin VIDEO SOURCES
14021 Below is a description of the currently available video sources.
14025 Buffer video frames, and make them available to the filter chain.
14027 This source is mainly intended for a programmatic use, in particular
14028 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
14030 It accepts the following parameters:
14035 Specify the size (width and height) of the buffered video frames. For the
14036 syntax of this option, check the
14037 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14040 The input video width.
14043 The input video height.
14046 A string representing the pixel format of the buffered video frames.
14047 It may be a number corresponding to a pixel format, or a pixel format
14051 Specify the timebase assumed by the timestamps of the buffered frames.
14054 Specify the frame rate expected for the video stream.
14056 @item pixel_aspect, sar
14057 The sample (pixel) aspect ratio of the input video.
14060 Specify the optional parameters to be used for the scale filter which
14061 is automatically inserted when an input change is detected in the
14062 input size or format.
14064 @item hw_frames_ctx
14065 When using a hardware pixel format, this should be a reference to an
14066 AVHWFramesContext describing input frames.
14071 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
14074 will instruct the source to accept video frames with size 320x240 and
14075 with format "yuv410p", assuming 1/24 as the timestamps timebase and
14076 square pixels (1:1 sample aspect ratio).
14077 Since the pixel format with name "yuv410p" corresponds to the number 6
14078 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
14079 this example corresponds to:
14081 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
14084 Alternatively, the options can be specified as a flat string, but this
14085 syntax is deprecated:
14087 @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}]
14091 Create a pattern generated by an elementary cellular automaton.
14093 The initial state of the cellular automaton can be defined through the
14094 @option{filename}, and @option{pattern} options. If such options are
14095 not specified an initial state is created randomly.
14097 At each new frame a new row in the video is filled with the result of
14098 the cellular automaton next generation. The behavior when the whole
14099 frame is filled is defined by the @option{scroll} option.
14101 This source accepts the following options:
14105 Read the initial cellular automaton state, i.e. the starting row, from
14106 the specified file.
14107 In the file, each non-whitespace character is considered an alive
14108 cell, a newline will terminate the row, and further characters in the
14109 file will be ignored.
14112 Read the initial cellular automaton state, i.e. the starting row, from
14113 the specified string.
14115 Each non-whitespace character in the string is considered an alive
14116 cell, a newline will terminate the row, and further characters in the
14117 string will be ignored.
14120 Set the video rate, that is the number of frames generated per second.
14123 @item random_fill_ratio, ratio
14124 Set the random fill ratio for the initial cellular automaton row. It
14125 is a floating point number value ranging from 0 to 1, defaults to
14128 This option is ignored when a file or a pattern is specified.
14130 @item random_seed, seed
14131 Set the seed for filling randomly the initial row, must be an integer
14132 included between 0 and UINT32_MAX. If not specified, or if explicitly
14133 set to -1, the filter will try to use a good random seed on a best
14137 Set the cellular automaton rule, it is a number ranging from 0 to 255.
14138 Default value is 110.
14141 Set the size of the output video. For the syntax of this option, check the
14142 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14144 If @option{filename} or @option{pattern} is specified, the size is set
14145 by default to the width of the specified initial state row, and the
14146 height is set to @var{width} * PHI.
14148 If @option{size} is set, it must contain the width of the specified
14149 pattern string, and the specified pattern will be centered in the
14152 If a filename or a pattern string is not specified, the size value
14153 defaults to "320x518" (used for a randomly generated initial state).
14156 If set to 1, scroll the output upward when all the rows in the output
14157 have been already filled. If set to 0, the new generated row will be
14158 written over the top row just after the bottom row is filled.
14161 @item start_full, full
14162 If set to 1, completely fill the output with generated rows before
14163 outputting the first frame.
14164 This is the default behavior, for disabling set the value to 0.
14167 If set to 1, stitch the left and right row edges together.
14168 This is the default behavior, for disabling set the value to 0.
14171 @subsection Examples
14175 Read the initial state from @file{pattern}, and specify an output of
14178 cellauto=f=pattern:s=200x400
14182 Generate a random initial row with a width of 200 cells, with a fill
14185 cellauto=ratio=2/3:s=200x200
14189 Create a pattern generated by rule 18 starting by a single alive cell
14190 centered on an initial row with width 100:
14192 cellauto=p=@@:s=100x400:full=0:rule=18
14196 Specify a more elaborated initial pattern:
14198 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
14203 @anchor{coreimagesrc}
14204 @section coreimagesrc
14205 Video source generated on GPU using Apple's CoreImage API on OSX.
14207 This video source is a specialized version of the @ref{coreimage} video filter.
14208 Use a core image generator at the beginning of the applied filterchain to
14209 generate the content.
14211 The coreimagesrc video source accepts the following options:
14213 @item list_generators
14214 List all available generators along with all their respective options as well as
14215 possible minimum and maximum values along with the default values.
14217 list_generators=true
14221 Specify the size of the sourced video. For the syntax of this option, check the
14222 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14223 The default value is @code{320x240}.
14226 Specify the frame rate of the sourced video, as the number of frames
14227 generated per second. It has to be a string in the format
14228 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
14229 number or a valid video frame rate abbreviation. The default value is
14233 Set the sample aspect ratio of the sourced video.
14236 Set the duration of the sourced video. See
14237 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
14238 for the accepted syntax.
14240 If not specified, or the expressed duration is negative, the video is
14241 supposed to be generated forever.
14244 Additionally, all options of the @ref{coreimage} video filter are accepted.
14245 A complete filterchain can be used for further processing of the
14246 generated input without CPU-HOST transfer. See @ref{coreimage} documentation
14247 and examples for details.
14249 @subsection Examples
14254 Use CIQRCodeGenerator to create a QR code for the FFmpeg homepage,
14255 given as complete and escaped command-line for Apple's standard bash shell:
14257 ffmpeg -f lavfi -i coreimagesrc=s=100x100:filter=CIQRCodeGenerator@@inputMessage=https\\\\\://FFmpeg.org/@@inputCorrectionLevel=H -frames:v 1 QRCode.png
14259 This example is equivalent to the QRCode example of @ref{coreimage} without the
14260 need for a nullsrc video source.
14264 @section mandelbrot
14266 Generate a Mandelbrot set fractal, and progressively zoom towards the
14267 point specified with @var{start_x} and @var{start_y}.
14269 This source accepts the following options:
14274 Set the terminal pts value. Default value is 400.
14277 Set the terminal scale value.
14278 Must be a floating point value. Default value is 0.3.
14281 Set the inner coloring mode, that is the algorithm used to draw the
14282 Mandelbrot fractal internal region.
14284 It shall assume one of the following values:
14289 Show time until convergence.
14291 Set color based on point closest to the origin of the iterations.
14296 Default value is @var{mincol}.
14299 Set the bailout value. Default value is 10.0.
14302 Set the maximum of iterations performed by the rendering
14303 algorithm. Default value is 7189.
14306 Set outer coloring mode.
14307 It shall assume one of following values:
14309 @item iteration_count
14310 Set iteration cound mode.
14311 @item normalized_iteration_count
14312 set normalized iteration count mode.
14314 Default value is @var{normalized_iteration_count}.
14317 Set frame rate, expressed as number of frames per second. Default
14321 Set frame size. For the syntax of this option, check the "Video
14322 size" section in the ffmpeg-utils manual. Default value is "640x480".
14325 Set the initial scale value. Default value is 3.0.
14328 Set the initial x position. Must be a floating point value between
14329 -100 and 100. Default value is -0.743643887037158704752191506114774.
14332 Set the initial y position. Must be a floating point value between
14333 -100 and 100. Default value is -0.131825904205311970493132056385139.
14338 Generate various test patterns, as generated by the MPlayer test filter.
14340 The size of the generated video is fixed, and is 256x256.
14341 This source is useful in particular for testing encoding features.
14343 This source accepts the following options:
14348 Specify the frame rate of the sourced video, as the number of frames
14349 generated per second. It has to be a string in the format
14350 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
14351 number or a valid video frame rate abbreviation. The default value is
14355 Set the duration of the sourced video. See
14356 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
14357 for the accepted syntax.
14359 If not specified, or the expressed duration is negative, the video is
14360 supposed to be generated forever.
14364 Set the number or the name of the test to perform. Supported tests are:
14380 Default value is "all", which will cycle through the list of all tests.
14385 mptestsrc=t=dc_luma
14388 will generate a "dc_luma" test pattern.
14390 @section frei0r_src
14392 Provide a frei0r source.
14394 To enable compilation of this filter you need to install the frei0r
14395 header and configure FFmpeg with @code{--enable-frei0r}.
14397 This source accepts the following parameters:
14402 The size of the video to generate. For the syntax of this option, check the
14403 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14406 The framerate of the generated video. It may be a string of the form
14407 @var{num}/@var{den} or a frame rate abbreviation.
14410 The name to the frei0r source to load. For more information regarding frei0r and
14411 how to set the parameters, read the @ref{frei0r} section in the video filters
14414 @item filter_params
14415 A '|'-separated list of parameters to pass to the frei0r source.
14419 For example, to generate a frei0r partik0l source with size 200x200
14420 and frame rate 10 which is overlaid on the overlay filter main input:
14422 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
14427 Generate a life pattern.
14429 This source is based on a generalization of John Conway's life game.
14431 The sourced input represents a life grid, each pixel represents a cell
14432 which can be in one of two possible states, alive or dead. Every cell
14433 interacts with its eight neighbours, which are the cells that are
14434 horizontally, vertically, or diagonally adjacent.
14436 At each interaction the grid evolves according to the adopted rule,
14437 which specifies the number of neighbor alive cells which will make a
14438 cell stay alive or born. The @option{rule} option allows one to specify
14441 This source accepts the following options:
14445 Set the file from which to read the initial grid state. In the file,
14446 each non-whitespace character is considered an alive cell, and newline
14447 is used to delimit the end of each row.
14449 If this option is not specified, the initial grid is generated
14453 Set the video rate, that is the number of frames generated per second.
14456 @item random_fill_ratio, ratio
14457 Set the random fill ratio for the initial random grid. It is a
14458 floating point number value ranging from 0 to 1, defaults to 1/PHI.
14459 It is ignored when a file is specified.
14461 @item random_seed, seed
14462 Set the seed for filling the initial random grid, must be an integer
14463 included between 0 and UINT32_MAX. If not specified, or if explicitly
14464 set to -1, the filter will try to use a good random seed on a best
14470 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
14471 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
14472 @var{NS} specifies the number of alive neighbor cells which make a
14473 live cell stay alive, and @var{NB} the number of alive neighbor cells
14474 which make a dead cell to become alive (i.e. to "born").
14475 "s" and "b" can be used in place of "S" and "B", respectively.
14477 Alternatively a rule can be specified by an 18-bits integer. The 9
14478 high order bits are used to encode the next cell state if it is alive
14479 for each number of neighbor alive cells, the low order bits specify
14480 the rule for "borning" new cells. Higher order bits encode for an
14481 higher number of neighbor cells.
14482 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
14483 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
14485 Default value is "S23/B3", which is the original Conway's game of life
14486 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
14487 cells, and will born a new cell if there are three alive cells around
14491 Set the size of the output video. For the syntax of this option, check the
14492 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14494 If @option{filename} is specified, the size is set by default to the
14495 same size of the input file. If @option{size} is set, it must contain
14496 the size specified in the input file, and the initial grid defined in
14497 that file is centered in the larger resulting area.
14499 If a filename is not specified, the size value defaults to "320x240"
14500 (used for a randomly generated initial grid).
14503 If set to 1, stitch the left and right grid edges together, and the
14504 top and bottom edges also. Defaults to 1.
14507 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
14508 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
14509 value from 0 to 255.
14512 Set the color of living (or new born) cells.
14515 Set the color of dead cells. If @option{mold} is set, this is the first color
14516 used to represent a dead cell.
14519 Set mold color, for definitely dead and moldy cells.
14521 For the syntax of these 3 color options, check the "Color" section in the
14522 ffmpeg-utils manual.
14525 @subsection Examples
14529 Read a grid from @file{pattern}, and center it on a grid of size
14532 life=f=pattern:s=300x300
14536 Generate a random grid of size 200x200, with a fill ratio of 2/3:
14538 life=ratio=2/3:s=200x200
14542 Specify a custom rule for evolving a randomly generated grid:
14548 Full example with slow death effect (mold) using @command{ffplay}:
14550 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
14557 @anchor{haldclutsrc}
14559 @anchor{rgbtestsrc}
14561 @anchor{smptehdbars}
14564 @section allrgb, allyuv, color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc, testsrc2
14566 The @code{allrgb} source returns frames of size 4096x4096 of all rgb colors.
14568 The @code{allyuv} source returns frames of size 4096x4096 of all yuv colors.
14570 The @code{color} source provides an uniformly colored input.
14572 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
14573 @ref{haldclut} filter.
14575 The @code{nullsrc} source returns unprocessed video frames. It is
14576 mainly useful to be employed in analysis / debugging tools, or as the
14577 source for filters which ignore the input data.
14579 The @code{rgbtestsrc} source generates an RGB test pattern useful for
14580 detecting RGB vs BGR issues. You should see a red, green and blue
14581 stripe from top to bottom.
14583 The @code{smptebars} source generates a color bars pattern, based on
14584 the SMPTE Engineering Guideline EG 1-1990.
14586 The @code{smptehdbars} source generates a color bars pattern, based on
14587 the SMPTE RP 219-2002.
14589 The @code{testsrc} source generates a test video pattern, showing a
14590 color pattern, a scrolling gradient and a timestamp. This is mainly
14591 intended for testing purposes.
14593 The @code{testsrc2} source is similar to testsrc, but supports more
14594 pixel formats instead of just @code{rgb24}. This allows using it as an
14595 input for other tests without requiring a format conversion.
14597 The sources accept the following parameters:
14602 Specify the color of the source, only available in the @code{color}
14603 source. For the syntax of this option, check the "Color" section in the
14604 ffmpeg-utils manual.
14607 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
14608 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
14609 pixels to be used as identity matrix for 3D lookup tables. Each component is
14610 coded on a @code{1/(N*N)} scale.
14613 Specify the size of the sourced video. For the syntax of this option, check the
14614 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14615 The default value is @code{320x240}.
14617 This option is not available with the @code{haldclutsrc} filter.
14620 Specify the frame rate of the sourced video, as the number of frames
14621 generated per second. It has to be a string in the format
14622 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
14623 number or a valid video frame rate abbreviation. The default value is
14627 Set the sample aspect ratio of the sourced video.
14630 Set the duration of the sourced video. See
14631 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
14632 for the accepted syntax.
14634 If not specified, or the expressed duration is negative, the video is
14635 supposed to be generated forever.
14638 Set the number of decimals to show in the timestamp, only available in the
14639 @code{testsrc} source.
14641 The displayed timestamp value will correspond to the original
14642 timestamp value multiplied by the power of 10 of the specified
14643 value. Default value is 0.
14646 For example the following:
14648 testsrc=duration=5.3:size=qcif:rate=10
14651 will generate a video with a duration of 5.3 seconds, with size
14652 176x144 and a frame rate of 10 frames per second.
14654 The following graph description will generate a red source
14655 with an opacity of 0.2, with size "qcif" and a frame rate of 10
14658 color=c=red@@0.2:s=qcif:r=10
14661 If the input content is to be ignored, @code{nullsrc} can be used. The
14662 following command generates noise in the luminance plane by employing
14663 the @code{geq} filter:
14665 nullsrc=s=256x256, geq=random(1)*255:128:128
14668 @subsection Commands
14670 The @code{color} source supports the following commands:
14674 Set the color of the created image. Accepts the same syntax of the
14675 corresponding @option{color} option.
14678 @c man end VIDEO SOURCES
14680 @chapter Video Sinks
14681 @c man begin VIDEO SINKS
14683 Below is a description of the currently available video sinks.
14685 @section buffersink
14687 Buffer video frames, and make them available to the end of the filter
14690 This sink is mainly intended for programmatic use, in particular
14691 through the interface defined in @file{libavfilter/buffersink.h}
14692 or the options system.
14694 It accepts a pointer to an AVBufferSinkContext structure, which
14695 defines the incoming buffers' formats, to be passed as the opaque
14696 parameter to @code{avfilter_init_filter} for initialization.
14700 Null video sink: do absolutely nothing with the input video. It is
14701 mainly useful as a template and for use in analysis / debugging
14704 @c man end VIDEO SINKS
14706 @chapter Multimedia Filters
14707 @c man begin MULTIMEDIA FILTERS
14709 Below is a description of the currently available multimedia filters.
14711 @section ahistogram
14713 Convert input audio to a video output, displaying the volume histogram.
14715 The filter accepts the following options:
14719 Specify how histogram is calculated.
14721 It accepts the following values:
14724 Use single histogram for all channels.
14726 Use separate histogram for each channel.
14728 Default is @code{single}.
14731 Set frame rate, expressed as number of frames per second. Default
14735 Specify the video size for the output. For the syntax of this option, check the
14736 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14737 Default value is @code{hd720}.
14742 It accepts the following values:
14753 reverse logarithmic
14755 Default is @code{log}.
14758 Set amplitude scale.
14760 It accepts the following values:
14767 Default is @code{log}.
14770 Set how much frames to accumulate in histogram.
14771 Defauls is 1. Setting this to -1 accumulates all frames.
14774 Set histogram ratio of window height.
14777 Set sonogram sliding.
14779 It accepts the following values:
14782 replace old rows with new ones.
14784 scroll from top to bottom.
14786 Default is @code{replace}.
14789 @section aphasemeter
14791 Convert input audio to a video output, displaying the audio phase.
14793 The filter accepts the following options:
14797 Set the output frame rate. Default value is @code{25}.
14800 Set the video size for the output. For the syntax of this option, check the
14801 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14802 Default value is @code{800x400}.
14807 Specify the red, green, blue contrast. Default values are @code{2},
14808 @code{7} and @code{1}.
14809 Allowed range is @code{[0, 255]}.
14812 Set color which will be used for drawing median phase. If color is
14813 @code{none} which is default, no median phase value will be drawn.
14816 The filter also exports the frame metadata @code{lavfi.aphasemeter.phase} which
14817 represents mean phase of current audio frame. Value is in range @code{[-1, 1]}.
14818 The @code{-1} means left and right channels are completely out of phase and
14819 @code{1} means channels are in phase.
14821 @section avectorscope
14823 Convert input audio to a video output, representing the audio vector
14826 The filter is used to measure the difference between channels of stereo
14827 audio stream. A monoaural signal, consisting of identical left and right
14828 signal, results in straight vertical line. Any stereo separation is visible
14829 as a deviation from this line, creating a Lissajous figure.
14830 If the straight (or deviation from it) but horizontal line appears this
14831 indicates that the left and right channels are out of phase.
14833 The filter accepts the following options:
14837 Set the vectorscope mode.
14839 Available values are:
14842 Lissajous rotated by 45 degrees.
14845 Same as above but not rotated.
14848 Shape resembling half of circle.
14851 Default value is @samp{lissajous}.
14854 Set the video size for the output. For the syntax of this option, check the
14855 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14856 Default value is @code{400x400}.
14859 Set the output frame rate. Default value is @code{25}.
14865 Specify the red, green, blue and alpha contrast. Default values are @code{40},
14866 @code{160}, @code{80} and @code{255}.
14867 Allowed range is @code{[0, 255]}.
14873 Specify the red, green, blue and alpha fade. Default values are @code{15},
14874 @code{10}, @code{5} and @code{5}.
14875 Allowed range is @code{[0, 255]}.
14878 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
14881 Set the vectorscope drawing mode.
14883 Available values are:
14886 Draw dot for each sample.
14889 Draw line between previous and current sample.
14892 Default value is @samp{dot}.
14895 @subsection Examples
14899 Complete example using @command{ffplay}:
14901 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
14902 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
14906 @section bench, abench
14908 Benchmark part of a filtergraph.
14910 The filter accepts the following options:
14914 Start or stop a timer.
14916 Available values are:
14919 Get the current time, set it as frame metadata (using the key
14920 @code{lavfi.bench.start_time}), and forward the frame to the next filter.
14923 Get the current time and fetch the @code{lavfi.bench.start_time} metadata from
14924 the input frame metadata to get the time difference. Time difference, average,
14925 maximum and minimum time (respectively @code{t}, @code{avg}, @code{max} and
14926 @code{min}) are then printed. The timestamps are expressed in seconds.
14930 @subsection Examples
14934 Benchmark @ref{selectivecolor} filter:
14936 bench=start,selectivecolor=reds=-.2 .12 -.49,bench=stop
14942 Concatenate audio and video streams, joining them together one after the
14945 The filter works on segments of synchronized video and audio streams. All
14946 segments must have the same number of streams of each type, and that will
14947 also be the number of streams at output.
14949 The filter accepts the following options:
14954 Set the number of segments. Default is 2.
14957 Set the number of output video streams, that is also the number of video
14958 streams in each segment. Default is 1.
14961 Set the number of output audio streams, that is also the number of audio
14962 streams in each segment. Default is 0.
14965 Activate unsafe mode: do not fail if segments have a different format.
14969 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
14970 @var{a} audio outputs.
14972 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
14973 segment, in the same order as the outputs, then the inputs for the second
14976 Related streams do not always have exactly the same duration, for various
14977 reasons including codec frame size or sloppy authoring. For that reason,
14978 related synchronized streams (e.g. a video and its audio track) should be
14979 concatenated at once. The concat filter will use the duration of the longest
14980 stream in each segment (except the last one), and if necessary pad shorter
14981 audio streams with silence.
14983 For this filter to work correctly, all segments must start at timestamp 0.
14985 All corresponding streams must have the same parameters in all segments; the
14986 filtering system will automatically select a common pixel format for video
14987 streams, and a common sample format, sample rate and channel layout for
14988 audio streams, but other settings, such as resolution, must be converted
14989 explicitly by the user.
14991 Different frame rates are acceptable but will result in variable frame rate
14992 at output; be sure to configure the output file to handle it.
14994 @subsection Examples
14998 Concatenate an opening, an episode and an ending, all in bilingual version
14999 (video in stream 0, audio in streams 1 and 2):
15001 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
15002 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
15003 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
15004 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
15008 Concatenate two parts, handling audio and video separately, using the
15009 (a)movie sources, and adjusting the resolution:
15011 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
15012 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
15013 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
15015 Note that a desync will happen at the stitch if the audio and video streams
15016 do not have exactly the same duration in the first file.
15023 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
15024 it unchanged. By default, it logs a message at a frequency of 10Hz with the
15025 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
15026 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
15028 The filter also has a video output (see the @var{video} option) with a real
15029 time graph to observe the loudness evolution. The graphic contains the logged
15030 message mentioned above, so it is not printed anymore when this option is set,
15031 unless the verbose logging is set. The main graphing area contains the
15032 short-term loudness (3 seconds of analysis), and the gauge on the right is for
15033 the momentary loudness (400 milliseconds).
15035 More information about the Loudness Recommendation EBU R128 on
15036 @url{http://tech.ebu.ch/loudness}.
15038 The filter accepts the following options:
15043 Activate the video output. The audio stream is passed unchanged whether this
15044 option is set or no. The video stream will be the first output stream if
15045 activated. Default is @code{0}.
15048 Set the video size. This option is for video only. For the syntax of this
15050 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15051 Default and minimum resolution is @code{640x480}.
15054 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
15055 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
15056 other integer value between this range is allowed.
15059 Set metadata injection. If set to @code{1}, the audio input will be segmented
15060 into 100ms output frames, each of them containing various loudness information
15061 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
15063 Default is @code{0}.
15066 Force the frame logging level.
15068 Available values are:
15071 information logging level
15073 verbose logging level
15076 By default, the logging level is set to @var{info}. If the @option{video} or
15077 the @option{metadata} options are set, it switches to @var{verbose}.
15082 Available modes can be cumulated (the option is a @code{flag} type). Possible
15086 Disable any peak mode (default).
15088 Enable sample-peak mode.
15090 Simple peak mode looking for the higher sample value. It logs a message
15091 for sample-peak (identified by @code{SPK}).
15093 Enable true-peak mode.
15095 If enabled, the peak lookup is done on an over-sampled version of the input
15096 stream for better peak accuracy. It logs a message for true-peak.
15097 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
15098 This mode requires a build with @code{libswresample}.
15102 Treat mono input files as "dual mono". If a mono file is intended for playback
15103 on a stereo system, its EBU R128 measurement will be perceptually incorrect.
15104 If set to @code{true}, this option will compensate for this effect.
15105 Multi-channel input files are not affected by this option.
15108 Set a specific pan law to be used for the measurement of dual mono files.
15109 This parameter is optional, and has a default value of -3.01dB.
15112 @subsection Examples
15116 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
15118 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
15122 Run an analysis with @command{ffmpeg}:
15124 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
15128 @section interleave, ainterleave
15130 Temporally interleave frames from several inputs.
15132 @code{interleave} works with video inputs, @code{ainterleave} with audio.
15134 These filters read frames from several inputs and send the oldest
15135 queued frame to the output.
15137 Input streams must have a well defined, monotonically increasing frame
15140 In order to submit one frame to output, these filters need to enqueue
15141 at least one frame for each input, so they cannot work in case one
15142 input is not yet terminated and will not receive incoming frames.
15144 For example consider the case when one input is a @code{select} filter
15145 which always drop input frames. The @code{interleave} filter will keep
15146 reading from that input, but it will never be able to send new frames
15147 to output until the input will send an end-of-stream signal.
15149 Also, depending on inputs synchronization, the filters will drop
15150 frames in case one input receives more frames than the other ones, and
15151 the queue is already filled.
15153 These filters accept the following options:
15157 Set the number of different inputs, it is 2 by default.
15160 @subsection Examples
15164 Interleave frames belonging to different streams using @command{ffmpeg}:
15166 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
15170 Add flickering blur effect:
15172 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
15176 @section perms, aperms
15178 Set read/write permissions for the output frames.
15180 These filters are mainly aimed at developers to test direct path in the
15181 following filter in the filtergraph.
15183 The filters accept the following options:
15187 Select the permissions mode.
15189 It accepts the following values:
15192 Do nothing. This is the default.
15194 Set all the output frames read-only.
15196 Set all the output frames directly writable.
15198 Make the frame read-only if writable, and writable if read-only.
15200 Set each output frame read-only or writable randomly.
15204 Set the seed for the @var{random} mode, must be an integer included between
15205 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
15206 @code{-1}, the filter will try to use a good random seed on a best effort
15210 Note: in case of auto-inserted filter between the permission filter and the
15211 following one, the permission might not be received as expected in that
15212 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
15213 perms/aperms filter can avoid this problem.
15215 @section realtime, arealtime
15217 Slow down filtering to match real time approximatively.
15219 These filters will pause the filtering for a variable amount of time to
15220 match the output rate with the input timestamps.
15221 They are similar to the @option{re} option to @code{ffmpeg}.
15223 They accept the following options:
15227 Time limit for the pauses. Any pause longer than that will be considered
15228 a timestamp discontinuity and reset the timer. Default is 2 seconds.
15231 @section select, aselect
15233 Select frames to pass in output.
15235 This filter accepts the following options:
15240 Set expression, which is evaluated for each input frame.
15242 If the expression is evaluated to zero, the frame is discarded.
15244 If the evaluation result is negative or NaN, the frame is sent to the
15245 first output; otherwise it is sent to the output with index
15246 @code{ceil(val)-1}, assuming that the input index starts from 0.
15248 For example a value of @code{1.2} corresponds to the output with index
15249 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
15252 Set the number of outputs. The output to which to send the selected
15253 frame is based on the result of the evaluation. Default value is 1.
15256 The expression can contain the following constants:
15260 The (sequential) number of the filtered frame, starting from 0.
15263 The (sequential) number of the selected frame, starting from 0.
15265 @item prev_selected_n
15266 The sequential number of the last selected frame. It's NAN if undefined.
15269 The timebase of the input timestamps.
15272 The PTS (Presentation TimeStamp) of the filtered video frame,
15273 expressed in @var{TB} units. It's NAN if undefined.
15276 The PTS of the filtered video frame,
15277 expressed in seconds. It's NAN if undefined.
15280 The PTS of the previously filtered video frame. It's NAN if undefined.
15282 @item prev_selected_pts
15283 The PTS of the last previously filtered video frame. It's NAN if undefined.
15285 @item prev_selected_t
15286 The PTS of the last previously selected video frame. It's NAN if undefined.
15289 The PTS of the first video frame in the video. It's NAN if undefined.
15292 The time of the first video frame in the video. It's NAN if undefined.
15294 @item pict_type @emph{(video only)}
15295 The type of the filtered frame. It can assume one of the following
15307 @item interlace_type @emph{(video only)}
15308 The frame interlace type. It can assume one of the following values:
15311 The frame is progressive (not interlaced).
15313 The frame is top-field-first.
15315 The frame is bottom-field-first.
15318 @item consumed_sample_n @emph{(audio only)}
15319 the number of selected samples before the current frame
15321 @item samples_n @emph{(audio only)}
15322 the number of samples in the current frame
15324 @item sample_rate @emph{(audio only)}
15325 the input sample rate
15328 This is 1 if the filtered frame is a key-frame, 0 otherwise.
15331 the position in the file of the filtered frame, -1 if the information
15332 is not available (e.g. for synthetic video)
15334 @item scene @emph{(video only)}
15335 value between 0 and 1 to indicate a new scene; a low value reflects a low
15336 probability for the current frame to introduce a new scene, while a higher
15337 value means the current frame is more likely to be one (see the example below)
15339 @item concatdec_select
15340 The concat demuxer can select only part of a concat input file by setting an
15341 inpoint and an outpoint, but the output packets may not be entirely contained
15342 in the selected interval. By using this variable, it is possible to skip frames
15343 generated by the concat demuxer which are not exactly contained in the selected
15346 This works by comparing the frame pts against the @var{lavf.concat.start_time}
15347 and the @var{lavf.concat.duration} packet metadata values which are also
15348 present in the decoded frames.
15350 The @var{concatdec_select} variable is -1 if the frame pts is at least
15351 start_time and either the duration metadata is missing or the frame pts is less
15352 than start_time + duration, 0 otherwise, and NaN if the start_time metadata is
15355 That basically means that an input frame is selected if its pts is within the
15356 interval set by the concat demuxer.
15360 The default value of the select expression is "1".
15362 @subsection Examples
15366 Select all frames in input:
15371 The example above is the same as:
15383 Select only I-frames:
15385 select='eq(pict_type\,I)'
15389 Select one frame every 100:
15391 select='not(mod(n\,100))'
15395 Select only frames contained in the 10-20 time interval:
15397 select=between(t\,10\,20)
15401 Select only I frames contained in the 10-20 time interval:
15403 select=between(t\,10\,20)*eq(pict_type\,I)
15407 Select frames with a minimum distance of 10 seconds:
15409 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
15413 Use aselect to select only audio frames with samples number > 100:
15415 aselect='gt(samples_n\,100)'
15419 Create a mosaic of the first scenes:
15421 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
15424 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
15428 Send even and odd frames to separate outputs, and compose them:
15430 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
15434 Select useful frames from an ffconcat file which is using inpoints and
15435 outpoints but where the source files are not intra frame only.
15437 ffmpeg -copyts -vsync 0 -segment_time_metadata 1 -i input.ffconcat -vf select=concatdec_select -af aselect=concatdec_select output.avi
15441 @section sendcmd, asendcmd
15443 Send commands to filters in the filtergraph.
15445 These filters read commands to be sent to other filters in the
15448 @code{sendcmd} must be inserted between two video filters,
15449 @code{asendcmd} must be inserted between two audio filters, but apart
15450 from that they act the same way.
15452 The specification of commands can be provided in the filter arguments
15453 with the @var{commands} option, or in a file specified by the
15454 @var{filename} option.
15456 These filters accept the following options:
15459 Set the commands to be read and sent to the other filters.
15461 Set the filename of the commands to be read and sent to the other
15465 @subsection Commands syntax
15467 A commands description consists of a sequence of interval
15468 specifications, comprising a list of commands to be executed when a
15469 particular event related to that interval occurs. The occurring event
15470 is typically the current frame time entering or leaving a given time
15473 An interval is specified by the following syntax:
15475 @var{START}[-@var{END}] @var{COMMANDS};
15478 The time interval is specified by the @var{START} and @var{END} times.
15479 @var{END} is optional and defaults to the maximum time.
15481 The current frame time is considered within the specified interval if
15482 it is included in the interval [@var{START}, @var{END}), that is when
15483 the time is greater or equal to @var{START} and is lesser than
15486 @var{COMMANDS} consists of a sequence of one or more command
15487 specifications, separated by ",", relating to that interval. The
15488 syntax of a command specification is given by:
15490 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
15493 @var{FLAGS} is optional and specifies the type of events relating to
15494 the time interval which enable sending the specified command, and must
15495 be a non-null sequence of identifier flags separated by "+" or "|" and
15496 enclosed between "[" and "]".
15498 The following flags are recognized:
15501 The command is sent when the current frame timestamp enters the
15502 specified interval. In other words, the command is sent when the
15503 previous frame timestamp was not in the given interval, and the
15507 The command is sent when the current frame timestamp leaves the
15508 specified interval. In other words, the command is sent when the
15509 previous frame timestamp was in the given interval, and the
15513 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
15516 @var{TARGET} specifies the target of the command, usually the name of
15517 the filter class or a specific filter instance name.
15519 @var{COMMAND} specifies the name of the command for the target filter.
15521 @var{ARG} is optional and specifies the optional list of argument for
15522 the given @var{COMMAND}.
15524 Between one interval specification and another, whitespaces, or
15525 sequences of characters starting with @code{#} until the end of line,
15526 are ignored and can be used to annotate comments.
15528 A simplified BNF description of the commands specification syntax
15531 @var{COMMAND_FLAG} ::= "enter" | "leave"
15532 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
15533 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
15534 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
15535 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
15536 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
15539 @subsection Examples
15543 Specify audio tempo change at second 4:
15545 asendcmd=c='4.0 atempo tempo 1.5',atempo
15549 Specify a list of drawtext and hue commands in a file.
15551 # show text in the interval 5-10
15552 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
15553 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
15555 # desaturate the image in the interval 15-20
15556 15.0-20.0 [enter] hue s 0,
15557 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
15559 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
15561 # apply an exponential saturation fade-out effect, starting from time 25
15562 25 [enter] hue s exp(25-t)
15565 A filtergraph allowing to read and process the above command list
15566 stored in a file @file{test.cmd}, can be specified with:
15568 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
15573 @section setpts, asetpts
15575 Change the PTS (presentation timestamp) of the input frames.
15577 @code{setpts} works on video frames, @code{asetpts} on audio frames.
15579 This filter accepts the following options:
15584 The expression which is evaluated for each frame to construct its timestamp.
15588 The expression is evaluated through the eval API and can contain the following
15593 frame rate, only defined for constant frame-rate video
15596 The presentation timestamp in input
15599 The count of the input frame for video or the number of consumed samples,
15600 not including the current frame for audio, starting from 0.
15602 @item NB_CONSUMED_SAMPLES
15603 The number of consumed samples, not including the current frame (only
15606 @item NB_SAMPLES, S
15607 The number of samples in the current frame (only audio)
15609 @item SAMPLE_RATE, SR
15610 The audio sample rate.
15613 The PTS of the first frame.
15616 the time in seconds of the first frame
15619 State whether the current frame is interlaced.
15622 the time in seconds of the current frame
15625 original position in the file of the frame, or undefined if undefined
15626 for the current frame
15629 The previous input PTS.
15632 previous input time in seconds
15635 The previous output PTS.
15638 previous output time in seconds
15641 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
15645 The wallclock (RTC) time at the start of the movie in microseconds.
15648 The timebase of the input timestamps.
15652 @subsection Examples
15656 Start counting PTS from zero
15658 setpts=PTS-STARTPTS
15662 Apply fast motion effect:
15668 Apply slow motion effect:
15674 Set fixed rate of 25 frames per second:
15680 Set fixed rate 25 fps with some jitter:
15682 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
15686 Apply an offset of 10 seconds to the input PTS:
15692 Generate timestamps from a "live source" and rebase onto the current timebase:
15694 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
15698 Generate timestamps by counting samples:
15705 @section settb, asettb
15707 Set the timebase to use for the output frames timestamps.
15708 It is mainly useful for testing timebase configuration.
15710 It accepts the following parameters:
15715 The expression which is evaluated into the output timebase.
15719 The value for @option{tb} is an arithmetic expression representing a
15720 rational. The expression can contain the constants "AVTB" (the default
15721 timebase), "intb" (the input timebase) and "sr" (the sample rate,
15722 audio only). Default value is "intb".
15724 @subsection Examples
15728 Set the timebase to 1/25:
15734 Set the timebase to 1/10:
15740 Set the timebase to 1001/1000:
15746 Set the timebase to 2*intb:
15752 Set the default timebase value:
15759 Convert input audio to a video output representing frequency spectrum
15760 logarithmically using Brown-Puckette constant Q transform algorithm with
15761 direct frequency domain coefficient calculation (but the transform itself
15762 is not really constant Q, instead the Q factor is actually variable/clamped),
15763 with musical tone scale, from E0 to D#10.
15765 The filter accepts the following options:
15769 Specify the video size for the output. It must be even. For the syntax of this option,
15770 check the @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15771 Default value is @code{1920x1080}.
15774 Set the output frame rate. Default value is @code{25}.
15777 Set the bargraph height. It must be even. Default value is @code{-1} which
15778 computes the bargraph height automatically.
15781 Set the axis height. It must be even. Default value is @code{-1} which computes
15782 the axis height automatically.
15785 Set the sonogram height. It must be even. Default value is @code{-1} which
15786 computes the sonogram height automatically.
15789 Set the fullhd resolution. This option is deprecated, use @var{size}, @var{s}
15790 instead. Default value is @code{1}.
15792 @item sono_v, volume
15793 Specify the sonogram volume expression. It can contain variables:
15796 the @var{bar_v} evaluated expression
15797 @item frequency, freq, f
15798 the frequency where it is evaluated
15799 @item timeclamp, tc
15800 the value of @var{timeclamp} option
15804 @item a_weighting(f)
15805 A-weighting of equal loudness
15806 @item b_weighting(f)
15807 B-weighting of equal loudness
15808 @item c_weighting(f)
15809 C-weighting of equal loudness.
15811 Default value is @code{16}.
15813 @item bar_v, volume2
15814 Specify the bargraph volume expression. It can contain variables:
15817 the @var{sono_v} evaluated expression
15818 @item frequency, freq, f
15819 the frequency where it is evaluated
15820 @item timeclamp, tc
15821 the value of @var{timeclamp} option
15825 @item a_weighting(f)
15826 A-weighting of equal loudness
15827 @item b_weighting(f)
15828 B-weighting of equal loudness
15829 @item c_weighting(f)
15830 C-weighting of equal loudness.
15832 Default value is @code{sono_v}.
15834 @item sono_g, gamma
15835 Specify the sonogram gamma. Lower gamma makes the spectrum more contrast,
15836 higher gamma makes the spectrum having more range. Default value is @code{3}.
15837 Acceptable range is @code{[1, 7]}.
15839 @item bar_g, gamma2
15840 Specify the bargraph gamma. Default value is @code{1}. Acceptable range is
15843 @item timeclamp, tc
15844 Specify the transform timeclamp. At low frequency, there is trade-off between
15845 accuracy in time domain and frequency domain. If timeclamp is lower,
15846 event in time domain is represented more accurately (such as fast bass drum),
15847 otherwise event in frequency domain is represented more accurately
15848 (such as bass guitar). Acceptable range is @code{[0.1, 1]}. Default value is @code{0.17}.
15851 Specify the transform base frequency. Default value is @code{20.01523126408007475},
15852 which is frequency 50 cents below E0. Acceptable range is @code{[10, 100000]}.
15855 Specify the transform end frequency. Default value is @code{20495.59681441799654},
15856 which is frequency 50 cents above D#10. Acceptable range is @code{[10, 100000]}.
15859 This option is deprecated and ignored.
15862 Specify the transform length in time domain. Use this option to control accuracy
15863 trade-off between time domain and frequency domain at every frequency sample.
15864 It can contain variables:
15866 @item frequency, freq, f
15867 the frequency where it is evaluated
15868 @item timeclamp, tc
15869 the value of @var{timeclamp} option.
15871 Default value is @code{384*tc/(384+tc*f)}.
15874 Specify the transform count for every video frame. Default value is @code{6}.
15875 Acceptable range is @code{[1, 30]}.
15878 Specify the transform count for every single pixel. Default value is @code{0},
15879 which makes it computed automatically. Acceptable range is @code{[0, 10]}.
15882 Specify font file for use with freetype to draw the axis. If not specified,
15883 use embedded font. Note that drawing with font file or embedded font is not
15884 implemented with custom @var{basefreq} and @var{endfreq}, use @var{axisfile}
15888 Specify font color expression. This is arithmetic expression that should return
15889 integer value 0xRRGGBB. It can contain variables:
15891 @item frequency, freq, f
15892 the frequency where it is evaluated
15893 @item timeclamp, tc
15894 the value of @var{timeclamp} option
15899 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
15900 @item r(x), g(x), b(x)
15901 red, green, and blue value of intensity x.
15903 Default value is @code{st(0, (midi(f)-59.5)/12);
15904 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
15905 r(1-ld(1)) + b(ld(1))}.
15908 Specify image file to draw the axis. This option override @var{fontfile} and
15909 @var{fontcolor} option.
15912 Enable/disable drawing text to the axis. If it is set to @code{0}, drawing to
15913 the axis is disabled, ignoring @var{fontfile} and @var{axisfile} option.
15914 Default value is @code{1}.
15918 @subsection Examples
15922 Playing audio while showing the spectrum:
15924 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
15928 Same as above, but with frame rate 30 fps:
15930 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
15934 Playing at 1280x720:
15936 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=s=1280x720:count=4 [out0]'
15940 Disable sonogram display:
15946 A1 and its harmonics: A1, A2, (near)E3, A3:
15948 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),
15949 asplit[a][out1]; [a] showcqt [out0]'
15953 Same as above, but with more accuracy in frequency domain:
15955 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),
15956 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
15962 bar_v=10:sono_v=bar_v*a_weighting(f)
15966 Custom gamma, now spectrum is linear to the amplitude.
15972 Custom tlength equation:
15974 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)))'
15978 Custom fontcolor and fontfile, C-note is colored green, others are colored blue:
15980 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))':fontfile=myfont.ttf
15984 Custom frequency range with custom axis using image file:
15986 axisfile=myaxis.png:basefreq=40:endfreq=10000
15992 Convert input audio to video output representing the audio power spectrum.
15993 Audio amplitude is on Y-axis while frequency is on X-axis.
15995 The filter accepts the following options:
15999 Specify size of video. For the syntax of this option, check the
16000 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16001 Default is @code{1024x512}.
16005 This set how each frequency bin will be represented.
16007 It accepts the following values:
16013 Default is @code{bar}.
16016 Set amplitude scale.
16018 It accepts the following values:
16032 Default is @code{log}.
16035 Set frequency scale.
16037 It accepts the following values:
16046 Reverse logarithmic scale.
16048 Default is @code{lin}.
16053 It accepts the following values:
16069 Default is @code{w2048}
16072 Set windowing function.
16074 It accepts the following values:
16092 Default is @code{hanning}.
16095 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
16096 which means optimal overlap for selected window function will be picked.
16099 Set time averaging. Setting this to 0 will display current maximal peaks.
16100 Default is @code{1}, which means time averaging is disabled.
16103 Specify list of colors separated by space or by '|' which will be used to
16104 draw channel frequencies. Unrecognized or missing colors will be replaced
16108 Set channel display mode.
16110 It accepts the following values:
16115 Default is @code{combined}.
16119 @anchor{showspectrum}
16120 @section showspectrum
16122 Convert input audio to a video output, representing the audio frequency
16125 The filter accepts the following options:
16129 Specify the video size for the output. For the syntax of this option, check the
16130 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16131 Default value is @code{640x512}.
16134 Specify how the spectrum should slide along the window.
16136 It accepts the following values:
16139 the samples start again on the left when they reach the right
16141 the samples scroll from right to left
16143 the samples scroll from left to right
16145 frames are only produced when the samples reach the right
16148 Default value is @code{replace}.
16151 Specify display mode.
16153 It accepts the following values:
16156 all channels are displayed in the same row
16158 all channels are displayed in separate rows
16161 Default value is @samp{combined}.
16164 Specify display color mode.
16166 It accepts the following values:
16169 each channel is displayed in a separate color
16171 each channel is displayed using the same color scheme
16173 each channel is displayed using the rainbow color scheme
16175 each channel is displayed using the moreland color scheme
16177 each channel is displayed using the nebulae color scheme
16179 each channel is displayed using the fire color scheme
16181 each channel is displayed using the fiery color scheme
16183 each channel is displayed using the fruit color scheme
16185 each channel is displayed using the cool color scheme
16188 Default value is @samp{channel}.
16191 Specify scale used for calculating intensity color values.
16193 It accepts the following values:
16198 square root, default
16209 Default value is @samp{sqrt}.
16212 Set saturation modifier for displayed colors. Negative values provide
16213 alternative color scheme. @code{0} is no saturation at all.
16214 Saturation must be in [-10.0, 10.0] range.
16215 Default value is @code{1}.
16218 Set window function.
16220 It accepts the following values:
16240 Default value is @code{hann}.
16243 Set orientation of time vs frequency axis. Can be @code{vertical} or
16244 @code{horizontal}. Default is @code{vertical}.
16247 Set ratio of overlap window. Default value is @code{0}.
16248 When value is @code{1} overlap is set to recommended size for specific
16249 window function currently used.
16252 Set scale gain for calculating intensity color values.
16253 Default value is @code{1}.
16256 Set which data to display. Can be @code{magnitude}, default or @code{phase}.
16259 The usage is very similar to the showwaves filter; see the examples in that
16262 @subsection Examples
16266 Large window with logarithmic color scaling:
16268 showspectrum=s=1280x480:scale=log
16272 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
16274 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
16275 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
16279 @section showspectrumpic
16281 Convert input audio to a single video frame, representing the audio frequency
16284 The filter accepts the following options:
16288 Specify the video size for the output. For the syntax of this option, check the
16289 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16290 Default value is @code{4096x2048}.
16293 Specify display mode.
16295 It accepts the following values:
16298 all channels are displayed in the same row
16300 all channels are displayed in separate rows
16302 Default value is @samp{combined}.
16305 Specify display color mode.
16307 It accepts the following values:
16310 each channel is displayed in a separate color
16312 each channel is displayed using the same color scheme
16314 each channel is displayed using the rainbow color scheme
16316 each channel is displayed using the moreland color scheme
16318 each channel is displayed using the nebulae color scheme
16320 each channel is displayed using the fire color scheme
16322 each channel is displayed using the fiery color scheme
16324 each channel is displayed using the fruit color scheme
16326 each channel is displayed using the cool color scheme
16328 Default value is @samp{intensity}.
16331 Specify scale used for calculating intensity color values.
16333 It accepts the following values:
16338 square root, default
16348 Default value is @samp{log}.
16351 Set saturation modifier for displayed colors. Negative values provide
16352 alternative color scheme. @code{0} is no saturation at all.
16353 Saturation must be in [-10.0, 10.0] range.
16354 Default value is @code{1}.
16357 Set window function.
16359 It accepts the following values:
16378 Default value is @code{hann}.
16381 Set orientation of time vs frequency axis. Can be @code{vertical} or
16382 @code{horizontal}. Default is @code{vertical}.
16385 Set scale gain for calculating intensity color values.
16386 Default value is @code{1}.
16389 Draw time and frequency axes and legends. Default is enabled.
16392 @subsection Examples
16396 Extract an audio spectrogram of a whole audio track
16397 in a 1024x1024 picture using @command{ffmpeg}:
16399 ffmpeg -i audio.flac -lavfi showspectrumpic=s=1024x1024 spectrogram.png
16403 @section showvolume
16405 Convert input audio volume to a video output.
16407 The filter accepts the following options:
16414 Set border width, allowed range is [0, 5]. Default is 1.
16417 Set channel width, allowed range is [80, 8192]. Default is 400.
16420 Set channel height, allowed range is [1, 900]. Default is 20.
16423 Set fade, allowed range is [0.001, 1]. Default is 0.95.
16426 Set volume color expression.
16428 The expression can use the following variables:
16432 Current max volume of channel in dB.
16435 Current channel number, starting from 0.
16439 If set, displays channel names. Default is enabled.
16442 If set, displays volume values. Default is enabled.
16445 Set orientation, can be @code{horizontal} or @code{vertical},
16446 default is @code{horizontal}.
16449 Set step size, allowed range s [0, 5]. Default is 0, which means
16455 Convert input audio to a video output, representing the samples waves.
16457 The filter accepts the following options:
16461 Specify the video size for the output. For the syntax of this option, check the
16462 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16463 Default value is @code{600x240}.
16468 Available values are:
16471 Draw a point for each sample.
16474 Draw a vertical line for each sample.
16477 Draw a point for each sample and a line between them.
16480 Draw a centered vertical line for each sample.
16483 Default value is @code{point}.
16486 Set the number of samples which are printed on the same column. A
16487 larger value will decrease the frame rate. Must be a positive
16488 integer. This option can be set only if the value for @var{rate}
16489 is not explicitly specified.
16492 Set the (approximate) output frame rate. This is done by setting the
16493 option @var{n}. Default value is "25".
16495 @item split_channels
16496 Set if channels should be drawn separately or overlap. Default value is 0.
16499 Set colors separated by '|' which are going to be used for drawing of each channel.
16502 Set amplitude scale. Can be linear @code{lin} or logarithmic @code{log}.
16507 @subsection Examples
16511 Output the input file audio and the corresponding video representation
16514 amovie=a.mp3,asplit[out0],showwaves[out1]
16518 Create a synthetic signal and show it with showwaves, forcing a
16519 frame rate of 30 frames per second:
16521 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
16525 @section showwavespic
16527 Convert input audio to a single video frame, representing the samples waves.
16529 The filter accepts the following options:
16533 Specify the video size for the output. For the syntax of this option, check the
16534 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16535 Default value is @code{600x240}.
16537 @item split_channels
16538 Set if channels should be drawn separately or overlap. Default value is 0.
16541 Set colors separated by '|' which are going to be used for drawing of each channel.
16544 Set amplitude scale. Can be linear @code{lin} or logarithmic @code{log}.
16548 @subsection Examples
16552 Extract a channel split representation of the wave form of a whole audio track
16553 in a 1024x800 picture using @command{ffmpeg}:
16555 ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png
16559 Colorize the waveform with colorchannelmixer. This example will make
16560 the waveform a green color approximately RGB(66,217,150). Additional
16561 channels will be shades of this color.
16563 ffmpeg -i audio.mp3 -filter_complex "showwavespic,colorchannelmixer=rr=66/255:gg=217/255:bb=150/255" waveform.png
16567 @section spectrumsynth
16569 Sythesize audio from 2 input video spectrums, first input stream represents
16570 magnitude across time and second represents phase across time.
16571 The filter will transform from frequency domain as displayed in videos back
16572 to time domain as presented in audio output.
16574 This filter is primarly created for reversing processed @ref{showspectrum}
16575 filter outputs, but can synthesize sound from other spectrograms too.
16576 But in such case results are going to be poor if the phase data is not
16577 available, because in such cases phase data need to be recreated, usually
16578 its just recreated from random noise.
16579 For best results use gray only output (@code{channel} color mode in
16580 @ref{showspectrum} filter) and @code{log} scale for magnitude video and
16581 @code{lin} scale for phase video. To produce phase, for 2nd video, use
16582 @code{data} option. Inputs videos should generally use @code{fullframe}
16583 slide mode as that saves resources needed for decoding video.
16585 The filter accepts the following options:
16589 Specify sample rate of output audio, the sample rate of audio from which
16590 spectrum was generated may differ.
16593 Set number of channels represented in input video spectrums.
16596 Set scale which was used when generating magnitude input spectrum.
16597 Can be @code{lin} or @code{log}. Default is @code{log}.
16600 Set slide which was used when generating inputs spectrums.
16601 Can be @code{replace}, @code{scroll}, @code{fullframe} or @code{rscroll}.
16602 Default is @code{fullframe}.
16605 Set window function used for resynthesis.
16608 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
16609 which means optimal overlap for selected window function will be picked.
16612 Set orientation of input videos. Can be @code{vertical} or @code{horizontal}.
16613 Default is @code{vertical}.
16616 @subsection Examples
16620 First create magnitude and phase videos from audio, assuming audio is stereo with 44100 sample rate,
16621 then resynthesize videos back to audio with spectrumsynth:
16623 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
16624 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
16625 ffmpeg -i magnitude.nut -i phase.nut -lavfi spectrumsynth=channels=2:sample_rate=44100:win_func=hann:overlap=0.875:slide=fullframe output.flac
16629 @section split, asplit
16631 Split input into several identical outputs.
16633 @code{asplit} works with audio input, @code{split} with video.
16635 The filter accepts a single parameter which specifies the number of outputs. If
16636 unspecified, it defaults to 2.
16638 @subsection Examples
16642 Create two separate outputs from the same input:
16644 [in] split [out0][out1]
16648 To create 3 or more outputs, you need to specify the number of
16651 [in] asplit=3 [out0][out1][out2]
16655 Create two separate outputs from the same input, one cropped and
16658 [in] split [splitout1][splitout2];
16659 [splitout1] crop=100:100:0:0 [cropout];
16660 [splitout2] pad=200:200:100:100 [padout];
16664 Create 5 copies of the input audio with @command{ffmpeg}:
16666 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
16672 Receive commands sent through a libzmq client, and forward them to
16673 filters in the filtergraph.
16675 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
16676 must be inserted between two video filters, @code{azmq} between two
16679 To enable these filters you need to install the libzmq library and
16680 headers and configure FFmpeg with @code{--enable-libzmq}.
16682 For more information about libzmq see:
16683 @url{http://www.zeromq.org/}
16685 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
16686 receives messages sent through a network interface defined by the
16687 @option{bind_address} option.
16689 The received message must be in the form:
16691 @var{TARGET} @var{COMMAND} [@var{ARG}]
16694 @var{TARGET} specifies the target of the command, usually the name of
16695 the filter class or a specific filter instance name.
16697 @var{COMMAND} specifies the name of the command for the target filter.
16699 @var{ARG} is optional and specifies the optional argument list for the
16700 given @var{COMMAND}.
16702 Upon reception, the message is processed and the corresponding command
16703 is injected into the filtergraph. Depending on the result, the filter
16704 will send a reply to the client, adopting the format:
16706 @var{ERROR_CODE} @var{ERROR_REASON}
16710 @var{MESSAGE} is optional.
16712 @subsection Examples
16714 Look at @file{tools/zmqsend} for an example of a zmq client which can
16715 be used to send commands processed by these filters.
16717 Consider the following filtergraph generated by @command{ffplay}
16719 ffplay -dumpgraph 1 -f lavfi "
16720 color=s=100x100:c=red [l];
16721 color=s=100x100:c=blue [r];
16722 nullsrc=s=200x100, zmq [bg];
16723 [bg][l] overlay [bg+l];
16724 [bg+l][r] overlay=x=100 "
16727 To change the color of the left side of the video, the following
16728 command can be used:
16730 echo Parsed_color_0 c yellow | tools/zmqsend
16733 To change the right side:
16735 echo Parsed_color_1 c pink | tools/zmqsend
16738 @c man end MULTIMEDIA FILTERS
16740 @chapter Multimedia Sources
16741 @c man begin MULTIMEDIA SOURCES
16743 Below is a description of the currently available multimedia sources.
16747 This is the same as @ref{movie} source, except it selects an audio
16753 Read audio and/or video stream(s) from a movie container.
16755 It accepts the following parameters:
16759 The name of the resource to read (not necessarily a file; it can also be a
16760 device or a stream accessed through some protocol).
16762 @item format_name, f
16763 Specifies the format assumed for the movie to read, and can be either
16764 the name of a container or an input device. If not specified, the
16765 format is guessed from @var{movie_name} or by probing.
16767 @item seek_point, sp
16768 Specifies the seek point in seconds. The frames will be output
16769 starting from this seek point. The parameter is evaluated with
16770 @code{av_strtod}, so the numerical value may be suffixed by an IS
16771 postfix. The default value is "0".
16774 Specifies the streams to read. Several streams can be specified,
16775 separated by "+". The source will then have as many outputs, in the
16776 same order. The syntax is explained in the ``Stream specifiers''
16777 section in the ffmpeg manual. Two special names, "dv" and "da" specify
16778 respectively the default (best suited) video and audio stream. Default
16779 is "dv", or "da" if the filter is called as "amovie".
16781 @item stream_index, si
16782 Specifies the index of the video stream to read. If the value is -1,
16783 the most suitable video stream will be automatically selected. The default
16784 value is "-1". Deprecated. If the filter is called "amovie", it will select
16785 audio instead of video.
16788 Specifies how many times to read the stream in sequence.
16789 If the value is less than 1, the stream will be read again and again.
16790 Default value is "1".
16792 Note that when the movie is looped the source timestamps are not
16793 changed, so it will generate non monotonically increasing timestamps.
16796 It allows overlaying a second video on top of the main input of
16797 a filtergraph, as shown in this graph:
16799 input -----------> deltapts0 --> overlay --> output
16802 movie --> scale--> deltapts1 -------+
16804 @subsection Examples
16808 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
16809 on top of the input labelled "in":
16811 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
16812 [in] setpts=PTS-STARTPTS [main];
16813 [main][over] overlay=16:16 [out]
16817 Read from a video4linux2 device, and overlay it on top of the input
16820 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
16821 [in] setpts=PTS-STARTPTS [main];
16822 [main][over] overlay=16:16 [out]
16826 Read the first video stream and the audio stream with id 0x81 from
16827 dvd.vob; the video is connected to the pad named "video" and the audio is
16828 connected to the pad named "audio":
16830 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
16834 @c man end MULTIMEDIA SOURCES