1 @chapter Filtering Introduction
2 @c man begin FILTERING INTRODUCTION
4 Filtering in FFmpeg is enabled through the libavfilter library.
6 In libavfilter, a filter can have multiple inputs and multiple
8 To illustrate the sorts of things that are possible, we consider the
13 input --> split ---------------------> overlay --> output
16 +-----> crop --> vflip -------+
19 This filtergraph splits the input stream in two streams, then sends one
20 stream through the crop filter and the vflip filter, before merging it
21 back with the other stream by overlaying it on top. You can use the
22 following command to achieve this:
25 ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
28 The result will be that the top half of the video is mirrored
29 onto the bottom half of the output video.
31 Filters in the same linear chain are separated by commas, and distinct
32 linear chains of filters are separated by semicolons. In our example,
33 @var{crop,vflip} are in one linear chain, @var{split} and
34 @var{overlay} are separately in another. The points where the linear
35 chains join are labelled by names enclosed in square brackets. In the
36 example, the split filter generates two outputs that are associated to
37 the labels @var{[main]} and @var{[tmp]}.
39 The stream sent to the second output of @var{split}, labelled as
40 @var{[tmp]}, is processed through the @var{crop} filter, which crops
41 away the lower half part of the video, and then vertically flipped. The
42 @var{overlay} filter takes in input the first unchanged output of the
43 split filter (which was labelled as @var{[main]}), and overlay on its
44 lower half the output generated by the @var{crop,vflip} filterchain.
46 Some filters take in input a list of parameters: they are specified
47 after the filter name and an equal sign, and are separated from each other
50 There exist so-called @var{source filters} that do not have an
51 audio/video input, and @var{sink filters} that will not have audio/video
54 @c man end FILTERING INTRODUCTION
57 @c man begin GRAPH2DOT
59 The @file{graph2dot} program included in the FFmpeg @file{tools}
60 directory can be used to parse a filtergraph description and issue a
61 corresponding textual representation in the dot language.
68 to see how to use @file{graph2dot}.
70 You can then pass the dot description to the @file{dot} program (from
71 the graphviz suite of programs) and obtain a graphical representation
74 For example the sequence of commands:
76 echo @var{GRAPH_DESCRIPTION} | \
77 tools/graph2dot -o graph.tmp && \
78 dot -Tpng graph.tmp -o graph.png && \
82 can be used to create and display an image representing the graph
83 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
84 a complete self-contained graph, with its inputs and outputs explicitly defined.
85 For example if your command line is of the form:
87 ffmpeg -i infile -vf scale=640:360 outfile
89 your @var{GRAPH_DESCRIPTION} string will need to be of the form:
91 nullsrc,scale=640:360,nullsink
93 you may also need to set the @var{nullsrc} parameters and add a @var{format}
94 filter in order to simulate a specific input file.
98 @chapter Filtergraph description
99 @c man begin FILTERGRAPH DESCRIPTION
101 A filtergraph is a directed graph of connected filters. It can contain
102 cycles, and there can be multiple links between a pair of
103 filters. Each link has one input pad on one side connecting it to one
104 filter from which it takes its input, and one output pad on the other
105 side connecting it to one filter accepting its output.
107 Each filter in a filtergraph is an instance of a filter class
108 registered in the application, which defines the features and the
109 number of input and output pads of the filter.
111 A filter with no input pads is called a "source", and a filter with no
112 output pads is called a "sink".
114 @anchor{Filtergraph syntax}
115 @section Filtergraph syntax
117 A filtergraph has a textual representation, which is recognized by the
118 @option{-filter}/@option{-vf}/@option{-af} and
119 @option{-filter_complex} options in @command{ffmpeg} and
120 @option{-vf}/@option{-af} in @command{ffplay}, and by the
121 @code{avfilter_graph_parse_ptr()} function defined in
122 @file{libavfilter/avfilter.h}.
124 A filterchain consists of a sequence of connected filters, each one
125 connected to the previous one in the sequence. A filterchain is
126 represented by a list of ","-separated filter descriptions.
128 A filtergraph consists of a sequence of filterchains. A sequence of
129 filterchains is represented by a list of ";"-separated filterchain
132 A filter is represented by a string of the form:
133 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
135 @var{filter_name} is the name of the filter class of which the
136 described filter is an instance of, and has to be the name of one of
137 the filter classes registered in the program.
138 The name of the filter class is optionally followed by a string
141 @var{arguments} is a string which contains the parameters used to
142 initialize the filter instance. It may have one of two forms:
146 A ':'-separated list of @var{key=value} pairs.
149 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
150 the option names in the order they are declared. E.g. the @code{fade} filter
151 declares three options in this order -- @option{type}, @option{start_frame} and
152 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
153 @var{in} is assigned to the option @option{type}, @var{0} to
154 @option{start_frame} and @var{30} to @option{nb_frames}.
157 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
158 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
159 follow the same constraints order of the previous point. The following
160 @var{key=value} pairs can be set in any preferred order.
164 If the option value itself is a list of items (e.g. the @code{format} filter
165 takes a list of pixel formats), the items in the list are usually separated by
168 The list of arguments can be quoted using the character @samp{'} as initial
169 and ending mark, and the character @samp{\} for escaping the characters
170 within the quoted text; otherwise the argument string is considered
171 terminated when the next special character (belonging to the set
172 @samp{[]=;,}) is encountered.
174 The name and arguments of the filter are optionally preceded and
175 followed by a list of link labels.
176 A link label allows one to name a link and associate it to a filter output
177 or input pad. The preceding labels @var{in_link_1}
178 ... @var{in_link_N}, are associated to the filter input pads,
179 the following labels @var{out_link_1} ... @var{out_link_M}, are
180 associated to the output pads.
182 When two link labels with the same name are found in the
183 filtergraph, a link between the corresponding input and output pad is
186 If an output pad is not labelled, it is linked by default to the first
187 unlabelled input pad of the next filter in the filterchain.
188 For example in the filterchain
190 nullsrc, split[L1], [L2]overlay, nullsink
192 the split filter instance has two output pads, and the overlay filter
193 instance two input pads. The first output pad of split is labelled
194 "L1", the first input pad of overlay is labelled "L2", and the second
195 output pad of split is linked to the second input pad of overlay,
196 which are both unlabelled.
198 In a filter description, if the input label of the first filter is not
199 specified, "in" is assumed; if the output label of the last filter is not
200 specified, "out" is assumed.
202 In a complete filterchain all the unlabelled filter input and output
203 pads must be connected. A filtergraph is considered valid if all the
204 filter input and output pads of all the filterchains are connected.
206 Libavfilter will automatically insert @ref{scale} filters where format
207 conversion is required. It is possible to specify swscale flags
208 for those automatically inserted scalers by prepending
209 @code{sws_flags=@var{flags};}
210 to the filtergraph description.
212 Here is a BNF description of the filtergraph syntax:
214 @var{NAME} ::= sequence of alphanumeric characters and '_'
215 @var{LINKLABEL} ::= "[" @var{NAME} "]"
216 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
217 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
218 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
219 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
220 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
223 @section Notes on filtergraph escaping
225 Filtergraph description composition entails several levels of
226 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
227 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
228 information about the employed escaping procedure.
230 A first level escaping affects the content of each filter option
231 value, which may contain the special character @code{:} used to
232 separate values, or one of the escaping characters @code{\'}.
234 A second level escaping affects the whole filter description, which
235 may contain the escaping characters @code{\'} or the special
236 characters @code{[],;} used by the filtergraph description.
238 Finally, when you specify a filtergraph on a shell commandline, you
239 need to perform a third level escaping for the shell special
240 characters contained within it.
242 For example, consider the following string to be embedded in
243 the @ref{drawtext} filter description @option{text} value:
245 this is a 'string': may contain one, or more, special characters
248 This string contains the @code{'} special escaping character, and the
249 @code{:} special character, so it needs to be escaped in this way:
251 text=this is a \'string\'\: may contain one, or more, special characters
254 A second level of escaping is required when embedding the filter
255 description in a filtergraph description, in order to escape all the
256 filtergraph special characters. Thus the example above becomes:
258 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
260 (note that in addition to the @code{\'} escaping special characters,
261 also @code{,} needs to be escaped).
263 Finally an additional level of escaping is needed when writing the
264 filtergraph description in a shell command, which depends on the
265 escaping rules of the adopted shell. For example, assuming that
266 @code{\} is special and needs to be escaped with another @code{\}, the
267 previous string will finally result in:
269 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
272 @chapter Timeline editing
274 Some filters support a generic @option{enable} option. For the filters
275 supporting timeline editing, this option can be set to an expression which is
276 evaluated before sending a frame to the filter. If the evaluation is non-zero,
277 the filter will be enabled, otherwise the frame will be sent unchanged to the
278 next filter in the filtergraph.
280 The expression accepts the following values:
283 timestamp expressed in seconds, NAN if the input timestamp is unknown
286 sequential number of the input frame, starting from 0
289 the position in the file of the input frame, NAN if unknown
293 width and height of the input frame if video
296 Additionally, these filters support an @option{enable} command that can be used
297 to re-define the expression.
299 Like any other filtering option, the @option{enable} option follows the same
302 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
303 minutes, and a @ref{curves} filter starting at 3 seconds:
305 smartblur = enable='between(t,10,3*60)',
306 curves = enable='gte(t,3)' : preset=cross_process
309 @c man end FILTERGRAPH DESCRIPTION
311 @chapter Audio Filters
312 @c man begin AUDIO FILTERS
314 When you configure your FFmpeg build, you can disable any of the
315 existing filters using @code{--disable-filters}.
316 The configure output will show the audio filters included in your
319 Below is a description of the currently available audio filters.
323 A compressor is mainly used to reduce the dynamic range of a signal.
324 Especially modern music is mostly compressed at a high ratio to
325 improve the overall loudness. It's done to get the highest attention
326 of a listener, "fatten" the sound and bring more "power" to the track.
327 If a signal is compressed too much it may sound dull or "dead"
328 afterwards or it may start to "pump" (which could be a powerful effect
329 but can also destroy a track completely).
330 The right compression is the key to reach a professional sound and is
331 the high art of mixing and mastering. Because of its complex settings
332 it may take a long time to get the right feeling for this kind of effect.
334 Compression is done by detecting the volume above a chosen level
335 @code{threshold} and dividing it by the factor set with @code{ratio}.
336 So if you set the threshold to -12dB and your signal reaches -6dB a ratio
337 of 2:1 will result in a signal at -9dB. Because an exact manipulation of
338 the signal would cause distortion of the waveform the reduction can be
339 levelled over the time. This is done by setting "Attack" and "Release".
340 @code{attack} determines how long the signal has to rise above the threshold
341 before any reduction will occur and @code{release} sets the time the signal
342 has to fall below the threshold to reduce the reduction again. Shorter signals
343 than the chosen attack time will be left untouched.
344 The overall reduction of the signal can be made up afterwards with the
345 @code{makeup} setting. So compressing the peaks of a signal about 6dB and
346 raising the makeup to this level results in a signal twice as loud than the
347 source. To gain a softer entry in the compression the @code{knee} flattens the
348 hard edge at the threshold in the range of the chosen decibels.
350 The filter accepts the following options:
354 Set input gain. Default is 1. Range is between 0.015625 and 64.
357 If a signal of second stream rises above this level it will affect the gain
358 reduction of the first stream.
359 By default it is 0.125. Range is between 0.00097563 and 1.
362 Set a ratio by which the signal is reduced. 1:2 means that if the level
363 rose 4dB above the threshold, it will be only 2dB above after the reduction.
364 Default is 2. Range is between 1 and 20.
367 Amount of milliseconds the signal has to rise above the threshold before gain
368 reduction starts. Default is 20. Range is between 0.01 and 2000.
371 Amount of milliseconds the signal has to fall below the threshold before
372 reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
375 Set the amount by how much signal will be amplified after processing.
376 Default is 2. Range is from 1 and 64.
379 Curve the sharp knee around the threshold to enter gain reduction more softly.
380 Default is 2.82843. Range is between 1 and 8.
383 Choose if the @code{average} level between all channels of input stream
384 or the louder(@code{maximum}) channel of input stream affects the
385 reduction. Default is @code{average}.
388 Should the exact signal be taken in case of @code{peak} or an RMS one in case
389 of @code{rms}. Default is @code{rms} which is mostly smoother.
392 How much to use compressed signal in output. Default is 1.
393 Range is between 0 and 1.
398 Apply cross fade from one input audio stream to another input audio stream.
399 The cross fade is applied for specified duration near the end of first stream.
401 The filter accepts the following options:
405 Specify the number of samples for which the cross fade effect has to last.
406 At the end of the cross fade effect the first input audio will be completely
407 silent. Default is 44100.
410 Specify the duration of the cross fade effect. See
411 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
412 for the accepted syntax.
413 By default the duration is determined by @var{nb_samples}.
414 If set this option is used instead of @var{nb_samples}.
417 Should first stream end overlap with second stream start. Default is enabled.
420 Set curve for cross fade transition for first stream.
423 Set curve for cross fade transition for second stream.
425 For description of available curve types see @ref{afade} filter description.
432 Cross fade from one input to another:
434 ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:c1=exp:c2=exp output.flac
438 Cross fade from one input to another but without overlapping:
440 ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:o=0:c1=exp:c2=exp output.flac
446 Delay one or more audio channels.
448 Samples in delayed channel are filled with silence.
450 The filter accepts the following option:
454 Set list of delays in milliseconds for each channel separated by '|'.
455 At least one delay greater than 0 should be provided.
456 Unused delays will be silently ignored. If number of given delays is
457 smaller than number of channels all remaining channels will not be delayed.
464 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
465 the second channel (and any other channels that may be present) unchanged.
473 Apply echoing to the input audio.
475 Echoes are reflected sound and can occur naturally amongst mountains
476 (and sometimes large buildings) when talking or shouting; digital echo
477 effects emulate this behaviour and are often used to help fill out the
478 sound of a single instrument or vocal. The time difference between the
479 original signal and the reflection is the @code{delay}, and the
480 loudness of the reflected signal is the @code{decay}.
481 Multiple echoes can have different delays and decays.
483 A description of the accepted parameters follows.
487 Set input gain of reflected signal. Default is @code{0.6}.
490 Set output gain of reflected signal. Default is @code{0.3}.
493 Set list of time intervals in milliseconds between original signal and reflections
494 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
495 Default is @code{1000}.
498 Set list of loudnesses of reflected signals separated by '|'.
499 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
500 Default is @code{0.5}.
507 Make it sound as if there are twice as many instruments as are actually playing:
509 aecho=0.8:0.88:60:0.4
513 If delay is very short, then it sound like a (metallic) robot playing music:
519 A longer delay will sound like an open air concert in the mountains:
521 aecho=0.8:0.9:1000:0.3
525 Same as above but with one more mountain:
527 aecho=0.8:0.9:1000|1800:0.3|0.25
532 Audio emphasis filter creates or restores material directly taken from LPs or
533 emphased CDs with different filter curves. E.g. to store music on vinyl the
534 signal has to be altered by a filter first to even out the disadvantages of
535 this recording medium.
536 Once the material is played back the inverse filter has to be applied to
537 restore the distortion of the frequency response.
539 The filter accepts the following options:
549 Set filter mode. For restoring material use @code{reproduction} mode, otherwise
550 use @code{production} mode. Default is @code{reproduction} mode.
553 Set filter type. Selects medium. Can be one of the following:
565 select Compact Disc (CD).
571 select 50µs (FM-KF).
573 select 75µs (FM-KF).
579 Modify an audio signal according to the specified expressions.
581 This filter accepts one or more expressions (one for each channel),
582 which are evaluated and used to modify a corresponding audio signal.
584 It accepts the following parameters:
588 Set the '|'-separated expressions list for each separate channel. If
589 the number of input channels is greater than the number of
590 expressions, the last specified expression is used for the remaining
593 @item channel_layout, c
594 Set output channel layout. If not specified, the channel layout is
595 specified by the number of expressions. If set to @samp{same}, it will
596 use by default the same input channel layout.
599 Each expression in @var{exprs} can contain the following constants and functions:
603 channel number of the current expression
606 number of the evaluated sample, starting from 0
612 time of the evaluated sample expressed in seconds
615 @item nb_out_channels
616 input and output number of channels
619 the value of input channel with number @var{CH}
622 Note: this filter is slow. For faster processing you should use a
631 aeval=val(ch)/2:c=same
635 Invert phase of the second channel:
644 Apply fade-in/out effect to input audio.
646 A description of the accepted parameters follows.
650 Specify the effect type, can be either @code{in} for fade-in, or
651 @code{out} for a fade-out effect. Default is @code{in}.
653 @item start_sample, ss
654 Specify the number of the start sample for starting to apply the fade
655 effect. Default is 0.
658 Specify the number of samples for which the fade effect has to last. At
659 the end of the fade-in effect the output audio will have the same
660 volume as the input audio, at the end of the fade-out transition
661 the output audio will be silence. Default is 44100.
664 Specify the start time of the fade effect. Default is 0.
665 The value must be specified as a time duration; see
666 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
667 for the accepted syntax.
668 If set this option is used instead of @var{start_sample}.
671 Specify the duration of the fade effect. See
672 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
673 for the accepted syntax.
674 At the end of the fade-in effect the output audio will have the same
675 volume as the input audio, at the end of the fade-out transition
676 the output audio will be silence.
677 By default the duration is determined by @var{nb_samples}.
678 If set this option is used instead of @var{nb_samples}.
681 Set curve for fade transition.
683 It accepts the following values:
686 select triangular, linear slope (default)
688 select quarter of sine wave
690 select half of sine wave
692 select exponential sine wave
696 select inverted parabola
710 select inverted quarter of sine wave
712 select inverted half of sine wave
714 select double-exponential seat
716 select double-exponential sigmoid
724 Fade in first 15 seconds of audio:
730 Fade out last 25 seconds of a 900 seconds audio:
732 afade=t=out:st=875:d=25
737 Apply arbitrary expressions to samples in frequency domain.
741 Set frequency domain real expression for each separate channel separated
742 by '|'. Default is "1".
743 If the number of input channels is greater than the number of
744 expressions, the last specified expression is used for the remaining
748 Set frequency domain imaginary expression for each separate channel
749 separated by '|'. If not set, @var{real} option is used.
751 Each expression in @var{real} and @var{imag} can contain the following
759 current frequency bin number
762 number of available bins
765 channel number of the current expression
777 It accepts the following values:
793 Default is @code{w4096}
796 Set window function. Default is @code{hann}.
799 Set window overlap. If set to 1, the recommended overlap for selected
800 window function will be picked. Default is @code{0.75}.
807 Leave almost only low frequencies in audio:
809 afftfilt="1-clip((b/nb)*b,0,1)"
816 Set output format constraints for the input audio. The framework will
817 negotiate the most appropriate format to minimize conversions.
819 It accepts the following parameters:
823 A '|'-separated list of requested sample formats.
826 A '|'-separated list of requested sample rates.
828 @item channel_layouts
829 A '|'-separated list of requested channel layouts.
831 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
832 for the required syntax.
835 If a parameter is omitted, all values are allowed.
837 Force the output to either unsigned 8-bit or signed 16-bit stereo
839 aformat=sample_fmts=u8|s16:channel_layouts=stereo
844 A gate is mainly used to reduce lower parts of a signal. This kind of signal
845 processing reduces disturbing noise between useful signals.
847 Gating is done by detecting the volume below a chosen level @var{threshold}
848 and divide it by the factor set with @var{ratio}. The bottom of the noise
849 floor is set via @var{range}. Because an exact manipulation of the signal
850 would cause distortion of the waveform the reduction can be levelled over
851 time. This is done by setting @var{attack} and @var{release}.
853 @var{attack} determines how long the signal has to fall below the threshold
854 before any reduction will occur and @var{release} sets the time the signal
855 has to raise above the threshold to reduce the reduction again.
856 Shorter signals than the chosen attack time will be left untouched.
860 Set input level before filtering.
861 Default is 1. Allowed range is from 0.015625 to 64.
864 Set the level of gain reduction when the signal is below the threshold.
865 Default is 0.06125. Allowed range is from 0 to 1.
868 If a signal rises above this level the gain reduction is released.
869 Default is 0.125. Allowed range is from 0 to 1.
872 Set a ratio about which the signal is reduced.
873 Default is 2. Allowed range is from 1 to 9000.
876 Amount of milliseconds the signal has to rise above the threshold before gain
878 Default is 20 milliseconds. Allowed range is from 0.01 to 9000.
881 Amount of milliseconds the signal has to fall below the threshold before the
882 reduction is increased again. Default is 250 milliseconds.
883 Allowed range is from 0.01 to 9000.
886 Set amount of amplification of signal after processing.
887 Default is 1. Allowed range is from 1 to 64.
890 Curve the sharp knee around the threshold to enter gain reduction more softly.
891 Default is 2.828427125. Allowed range is from 1 to 8.
894 Choose if exact signal should be taken for detection or an RMS like one.
895 Default is rms. Can be peak or rms.
898 Choose if the average level between all channels or the louder channel affects
900 Default is average. Can be average or maximum.
905 The limiter prevents input signal from raising over a desired threshold.
906 This limiter uses lookahead technology to prevent your signal from distorting.
907 It means that there is a small delay after signal is processed. Keep in mind
908 that the delay it produces is the attack time you set.
910 The filter accepts the following options:
914 Set input gain. Default is 1.
917 Set output gain. Default is 1.
920 Don't let signals above this level pass the limiter. Default is 1.
923 The limiter will reach its attenuation level in this amount of time in
924 milliseconds. Default is 5 milliseconds.
927 Come back from limiting to attenuation 1.0 in this amount of milliseconds.
928 Default is 50 milliseconds.
931 When gain reduction is always needed ASC takes care of releasing to an
932 average reduction level rather than reaching a reduction of 0 in the release
936 Select how much the release time is affected by ASC, 0 means nearly no changes
937 in release time while 1 produces higher release times.
940 Auto level output signal. Default is enabled.
941 This normalizes audio back to 0dB if enabled.
944 Depending on picked setting it is recommended to upsample input 2x or 4x times
945 with @ref{aresample} before applying this filter.
949 Apply a two-pole all-pass filter with central frequency (in Hz)
950 @var{frequency}, and filter-width @var{width}.
951 An all-pass filter changes the audio's frequency to phase relationship
952 without changing its frequency to amplitude relationship.
954 The filter accepts the following options:
961 Set method to specify band-width of filter.
974 Specify the band-width of a filter in width_type units.
980 Merge two or more audio streams into a single multi-channel stream.
982 The filter accepts the following options:
987 Set the number of inputs. Default is 2.
991 If the channel layouts of the inputs are disjoint, and therefore compatible,
992 the channel layout of the output will be set accordingly and the channels
993 will be reordered as necessary. If the channel layouts of the inputs are not
994 disjoint, the output will have all the channels of the first input then all
995 the channels of the second input, in that order, and the channel layout of
996 the output will be the default value corresponding to the total number of
999 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
1000 is FC+BL+BR, then the output will be in 5.1, with the channels in the
1001 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
1002 first input, b1 is the first channel of the second input).
1004 On the other hand, if both input are in stereo, the output channels will be
1005 in the default order: a1, a2, b1, b2, and the channel layout will be
1006 arbitrarily set to 4.0, which may or may not be the expected value.
1008 All inputs must have the same sample rate, and format.
1010 If inputs do not have the same duration, the output will stop with the
1013 @subsection Examples
1017 Merge two mono files into a stereo stream:
1019 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
1023 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
1025 ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv
1031 Mixes multiple audio inputs into a single output.
1033 Note that this filter only supports float samples (the @var{amerge}
1034 and @var{pan} audio filters support many formats). If the @var{amix}
1035 input has integer samples then @ref{aresample} will be automatically
1036 inserted to perform the conversion to float samples.
1040 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
1042 will mix 3 input audio streams to a single output with the same duration as the
1043 first input and a dropout transition time of 3 seconds.
1045 It accepts the following parameters:
1049 The number of inputs. If unspecified, it defaults to 2.
1052 How to determine the end-of-stream.
1056 The duration of the longest input. (default)
1059 The duration of the shortest input.
1062 The duration of the first input.
1066 @item dropout_transition
1067 The transition time, in seconds, for volume renormalization when an input
1068 stream ends. The default value is 2 seconds.
1072 @section anequalizer
1074 High-order parametric multiband equalizer for each channel.
1076 It accepts the following parameters:
1080 This option string is in format:
1081 "c@var{chn} f=@var{cf} w=@var{w} g=@var{g} t=@var{f} | ..."
1082 Each equalizer band is separated by '|'.
1086 Set channel number to which equalization will be applied.
1087 If input doesn't have that channel the entry is ignored.
1090 Set central frequency for band.
1091 If input doesn't have that frequency the entry is ignored.
1094 Set band width in hertz.
1097 Set band gain in dB.
1100 Set filter type for band, optional, can be:
1104 Butterworth, this is default.
1115 With this option activated frequency response of anequalizer is displayed
1119 Set video stream size. Only useful if curves option is activated.
1122 Set max gain that will be displayed. Only useful if curves option is activated.
1123 Setting this to reasonable value allows to display gain which is derived from
1124 neighbour bands which are too close to each other and thus produce higher gain
1125 when both are activated.
1128 Set frequency scale used to draw frequency response in video output.
1129 Can be linear or logarithmic. Default is logarithmic.
1132 Set color for each channel curve which is going to be displayed in video stream.
1133 This is list of color names separated by space or by '|'.
1134 Unrecognised or missing colors will be replaced by white color.
1137 @subsection Examples
1141 Lower gain by 10 of central frequency 200Hz and width 100 Hz
1142 for first 2 channels using Chebyshev type 1 filter:
1144 anequalizer=c0 f=200 w=100 g=-10 t=1|c1 f=200 w=100 g=-10 t=1
1148 @subsection Commands
1150 This filter supports the following commands:
1153 Alter existing filter parameters.
1154 Syntax for the commands is : "@var{fN}|f=@var{freq}|w=@var{width}|g=@var{gain}"
1156 @var{fN} is existing filter number, starting from 0, if no such filter is available
1158 @var{freq} set new frequency parameter.
1159 @var{width} set new width parameter in herz.
1160 @var{gain} set new gain parameter in dB.
1162 Full filter invocation with asendcmd may look like this:
1163 asendcmd=c='4.0 anequalizer change 0|f=200|w=50|g=1',anequalizer=...
1168 Pass the audio source unchanged to the output.
1172 Pad the end of an audio stream with silence.
1174 This can be used together with @command{ffmpeg} @option{-shortest} to
1175 extend audio streams to the same length as the video stream.
1177 A description of the accepted options follows.
1181 Set silence packet size. Default value is 4096.
1184 Set the number of samples of silence to add to the end. After the
1185 value is reached, the stream is terminated. This option is mutually
1186 exclusive with @option{whole_len}.
1189 Set the minimum total number of samples in the output audio stream. If
1190 the value is longer than the input audio length, silence is added to
1191 the end, until the value is reached. This option is mutually exclusive
1192 with @option{pad_len}.
1195 If neither the @option{pad_len} nor the @option{whole_len} option is
1196 set, the filter will add silence to the end of the input stream
1199 @subsection Examples
1203 Add 1024 samples of silence to the end of the input:
1209 Make sure the audio output will contain at least 10000 samples, pad
1210 the input with silence if required:
1212 apad=whole_len=10000
1216 Use @command{ffmpeg} to pad the audio input with silence, so that the
1217 video stream will always result the shortest and will be converted
1218 until the end in the output file when using the @option{shortest}
1221 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
1226 Add a phasing effect to the input audio.
1228 A phaser filter creates series of peaks and troughs in the frequency spectrum.
1229 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
1231 A description of the accepted parameters follows.
1235 Set input gain. Default is 0.4.
1238 Set output gain. Default is 0.74
1241 Set delay in milliseconds. Default is 3.0.
1244 Set decay. Default is 0.4.
1247 Set modulation speed in Hz. Default is 0.5.
1250 Set modulation type. Default is triangular.
1252 It accepts the following values:
1261 Audio pulsator is something between an autopanner and a tremolo.
1262 But it can produce funny stereo effects as well. Pulsator changes the volume
1263 of the left and right channel based on a LFO (low frequency oscillator) with
1264 different waveforms and shifted phases.
1265 This filter have the ability to define an offset between left and right
1266 channel. An offset of 0 means that both LFO shapes match each other.
1267 The left and right channel are altered equally - a conventional tremolo.
1268 An offset of 50% means that the shape of the right channel is exactly shifted
1269 in phase (or moved backwards about half of the frequency) - pulsator acts as
1270 an autopanner. At 1 both curves match again. Every setting in between moves the
1271 phase shift gapless between all stages and produces some "bypassing" sounds with
1272 sine and triangle waveforms. The more you set the offset near 1 (starting from
1273 the 0.5) the faster the signal passes from the left to the right speaker.
1275 The filter accepts the following options:
1279 Set input gain. By default it is 1. Range is [0.015625 - 64].
1282 Set output gain. By default it is 1. Range is [0.015625 - 64].
1285 Set waveform shape the LFO will use. Can be one of: sine, triangle, square,
1286 sawup or sawdown. Default is sine.
1289 Set modulation. Define how much of original signal is affected by the LFO.
1292 Set left channel offset. Default is 0. Allowed range is [0 - 1].
1295 Set right channel offset. Default is 0.5. Allowed range is [0 - 1].
1298 Set pulse width. Default is 1. Allowed range is [0 - 2].
1301 Set possible timing mode. Can be one of: bpm, ms or hz. Default is hz.
1304 Set bpm. Default is 120. Allowed range is [30 - 300]. Only used if timing
1308 Set ms. Default is 500. Allowed range is [10 - 2000]. Only used if timing
1312 Set frequency in Hz. Default is 2. Allowed range is [0.01 - 100]. Only used
1313 if timing is set to hz.
1319 Resample the input audio to the specified parameters, using the
1320 libswresample library. If none are specified then the filter will
1321 automatically convert between its input and output.
1323 This filter is also able to stretch/squeeze the audio data to make it match
1324 the timestamps or to inject silence / cut out audio to make it match the
1325 timestamps, do a combination of both or do neither.
1327 The filter accepts the syntax
1328 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
1329 expresses a sample rate and @var{resampler_options} is a list of
1330 @var{key}=@var{value} pairs, separated by ":". See the
1331 ffmpeg-resampler manual for the complete list of supported options.
1333 @subsection Examples
1337 Resample the input audio to 44100Hz:
1343 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
1344 samples per second compensation:
1346 aresample=async=1000
1350 @section asetnsamples
1352 Set the number of samples per each output audio frame.
1354 The last output packet may contain a different number of samples, as
1355 the filter will flush all the remaining samples when the input audio
1358 The filter accepts the following options:
1362 @item nb_out_samples, n
1363 Set the number of frames per each output audio frame. The number is
1364 intended as the number of samples @emph{per each channel}.
1365 Default value is 1024.
1368 If set to 1, the filter will pad the last audio frame with zeroes, so
1369 that the last frame will contain the same number of samples as the
1370 previous ones. Default value is 1.
1373 For example, to set the number of per-frame samples to 1234 and
1374 disable padding for the last frame, use:
1376 asetnsamples=n=1234:p=0
1381 Set the sample rate without altering the PCM data.
1382 This will result in a change of speed and pitch.
1384 The filter accepts the following options:
1387 @item sample_rate, r
1388 Set the output sample rate. Default is 44100 Hz.
1393 Show a line containing various information for each input audio frame.
1394 The input audio is not modified.
1396 The shown line contains a sequence of key/value pairs of the form
1397 @var{key}:@var{value}.
1399 The following values are shown in the output:
1403 The (sequential) number of the input frame, starting from 0.
1406 The presentation timestamp of the input frame, in time base units; the time base
1407 depends on the filter input pad, and is usually 1/@var{sample_rate}.
1410 The presentation timestamp of the input frame in seconds.
1413 position of the frame in the input stream, -1 if this information in
1414 unavailable and/or meaningless (for example in case of synthetic audio)
1423 The sample rate for the audio frame.
1426 The number of samples (per channel) in the frame.
1429 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
1430 audio, the data is treated as if all the planes were concatenated.
1432 @item plane_checksums
1433 A list of Adler-32 checksums for each data plane.
1439 Display time domain statistical information about the audio channels.
1440 Statistics are calculated and displayed for each audio channel and,
1441 where applicable, an overall figure is also given.
1443 It accepts the following option:
1446 Short window length in seconds, used for peak and trough RMS measurement.
1447 Default is @code{0.05} (50 milliseconds). Allowed range is @code{[0.1 - 10]}.
1451 Set metadata injection. All the metadata keys are prefixed with @code{lavfi.astats.X},
1452 where @code{X} is channel number starting from 1 or string @code{Overall}. Default is
1455 Available keys for each channel are:
1486 For example full key look like this @code{lavfi.astats.1.DC_offset} or
1487 this @code{lavfi.astats.Overall.Peak_count}.
1489 For description what each key means read below.
1492 Set number of frame after which stats are going to be recalculated.
1493 Default is disabled.
1496 A description of each shown parameter follows:
1500 Mean amplitude displacement from zero.
1503 Minimal sample level.
1506 Maximal sample level.
1508 @item Min difference
1509 Minimal difference between two consecutive samples.
1511 @item Max difference
1512 Maximal difference between two consecutive samples.
1514 @item Mean difference
1515 Mean difference between two consecutive samples.
1516 The average of each difference between two consecutive samples.
1520 Standard peak and RMS level measured in dBFS.
1524 Peak and trough values for RMS level measured over a short window.
1527 Standard ratio of peak to RMS level (note: not in dB).
1530 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
1531 (i.e. either @var{Min level} or @var{Max level}).
1534 Number of occasions (not the number of samples) that the signal attained either
1535 @var{Min level} or @var{Max level}.
1538 Overall bit depth of audio. Number of bits used for each sample.
1543 Synchronize audio data with timestamps by squeezing/stretching it and/or
1544 dropping samples/adding silence when needed.
1546 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1548 It accepts the following parameters:
1552 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1553 by default. When disabled, time gaps are covered with silence.
1556 The minimum difference between timestamps and audio data (in seconds) to trigger
1557 adding/dropping samples. The default value is 0.1. If you get an imperfect
1558 sync with this filter, try setting this parameter to 0.
1561 The maximum compensation in samples per second. Only relevant with compensate=1.
1562 The default value is 500.
1565 Assume that the first PTS should be this value. The time base is 1 / sample
1566 rate. This allows for padding/trimming at the start of the stream. By default,
1567 no assumption is made about the first frame's expected PTS, so no padding or
1568 trimming is done. For example, this could be set to 0 to pad the beginning with
1569 silence if an audio stream starts after the video stream or to trim any samples
1570 with a negative PTS due to encoder delay.
1578 The filter accepts exactly one parameter, the audio tempo. If not
1579 specified then the filter will assume nominal 1.0 tempo. Tempo must
1580 be in the [0.5, 2.0] range.
1582 @subsection Examples
1586 Slow down audio to 80% tempo:
1592 To speed up audio to 125% tempo:
1600 Trim the input so that the output contains one continuous subpart of the input.
1602 It accepts the following parameters:
1605 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1606 sample with the timestamp @var{start} will be the first sample in the output.
1609 Specify time of the first audio sample that will be dropped, i.e. the
1610 audio sample immediately preceding the one with the timestamp @var{end} will be
1611 the last sample in the output.
1614 Same as @var{start}, except this option sets the start timestamp in samples
1618 Same as @var{end}, except this option sets the end timestamp in samples instead
1622 The maximum duration of the output in seconds.
1625 The number of the first sample that should be output.
1628 The number of the first sample that should be dropped.
1631 @option{start}, @option{end}, and @option{duration} are expressed as time
1632 duration specifications; see
1633 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
1635 Note that the first two sets of the start/end options and the @option{duration}
1636 option look at the frame timestamp, while the _sample options simply count the
1637 samples that pass through the filter. So start/end_pts and start/end_sample will
1638 give different results when the timestamps are wrong, inexact or do not start at
1639 zero. Also note that this filter does not modify the timestamps. If you wish
1640 to have the output timestamps start at zero, insert the asetpts filter after the
1643 If multiple start or end options are set, this filter tries to be greedy and
1644 keep all samples that match at least one of the specified constraints. To keep
1645 only the part that matches all the constraints at once, chain multiple atrim
1648 The defaults are such that all the input is kept. So it is possible to set e.g.
1649 just the end values to keep everything before the specified time.
1654 Drop everything except the second minute of input:
1656 ffmpeg -i INPUT -af atrim=60:120
1660 Keep only the first 1000 samples:
1662 ffmpeg -i INPUT -af atrim=end_sample=1000
1669 Apply a two-pole Butterworth band-pass filter with central
1670 frequency @var{frequency}, and (3dB-point) band-width width.
1671 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1672 instead of the default: constant 0dB peak gain.
1673 The filter roll off at 6dB per octave (20dB per decade).
1675 The filter accepts the following options:
1679 Set the filter's central frequency. Default is @code{3000}.
1682 Constant skirt gain if set to 1. Defaults to 0.
1685 Set method to specify band-width of filter.
1698 Specify the band-width of a filter in width_type units.
1703 Apply a two-pole Butterworth band-reject filter with central
1704 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1705 The filter roll off at 6dB per octave (20dB per decade).
1707 The filter accepts the following options:
1711 Set the filter's central frequency. Default is @code{3000}.
1714 Set method to specify band-width of filter.
1727 Specify the band-width of a filter in width_type units.
1732 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1733 shelving filter with a response similar to that of a standard
1734 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1736 The filter accepts the following options:
1740 Give the gain at 0 Hz. Its useful range is about -20
1741 (for a large cut) to +20 (for a large boost).
1742 Beware of clipping when using a positive gain.
1745 Set the filter's central frequency and so can be used
1746 to extend or reduce the frequency range to be boosted or cut.
1747 The default value is @code{100} Hz.
1750 Set method to specify band-width of filter.
1763 Determine how steep is the filter's shelf transition.
1768 Apply a biquad IIR filter with the given coefficients.
1769 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1770 are the numerator and denominator coefficients respectively.
1773 Bauer stereo to binaural transformation, which improves headphone listening of
1774 stereo audio records.
1776 It accepts the following parameters:
1780 Pre-defined crossfeed level.
1784 Default level (fcut=700, feed=50).
1787 Chu Moy circuit (fcut=700, feed=60).
1790 Jan Meier circuit (fcut=650, feed=95).
1795 Cut frequency (in Hz).
1804 Remap input channels to new locations.
1806 It accepts the following parameters:
1808 @item channel_layout
1809 The channel layout of the output stream.
1812 Map channels from input to output. The argument is a '|'-separated list of
1813 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1814 @var{in_channel} form. @var{in_channel} can be either the name of the input
1815 channel (e.g. FL for front left) or its index in the input channel layout.
1816 @var{out_channel} is the name of the output channel or its index in the output
1817 channel layout. If @var{out_channel} is not given then it is implicitly an
1818 index, starting with zero and increasing by one for each mapping.
1821 If no mapping is present, the filter will implicitly map input channels to
1822 output channels, preserving indices.
1824 For example, assuming a 5.1+downmix input MOV file,
1826 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1828 will create an output WAV file tagged as stereo from the downmix channels of
1831 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1833 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:5.1' out.wav
1836 @section channelsplit
1838 Split each channel from an input audio stream into a separate output stream.
1840 It accepts the following parameters:
1842 @item channel_layout
1843 The channel layout of the input stream. The default is "stereo".
1846 For example, assuming a stereo input MP3 file,
1848 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1850 will create an output Matroska file with two audio streams, one containing only
1851 the left channel and the other the right channel.
1853 Split a 5.1 WAV file into per-channel files:
1855 ffmpeg -i in.wav -filter_complex
1856 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1857 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1858 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1863 Add a chorus effect to the audio.
1865 Can make a single vocal sound like a chorus, but can also be applied to instrumentation.
1867 Chorus resembles an echo effect with a short delay, but whereas with echo the delay is
1868 constant, with chorus, it is varied using using sinusoidal or triangular modulation.
1869 The modulation depth defines the range the modulated delay is played before or after
1870 the delay. Hence the delayed sound will sound slower or faster, that is the delayed
1871 sound tuned around the original one, like in a chorus where some vocals are slightly
1874 It accepts the following parameters:
1877 Set input gain. Default is 0.4.
1880 Set output gain. Default is 0.4.
1883 Set delays. A typical delay is around 40ms to 60ms.
1895 @subsection Examples
1901 chorus=0.7:0.9:55:0.4:0.25:2
1907 chorus=0.6:0.9:50|60:0.4|0.32:0.25|0.4:2|1.3
1911 Fuller sounding chorus with three delays:
1913 chorus=0.5:0.9:50|60|40:0.4|0.32|0.3:0.25|0.4|0.3:2|2.3|1.3
1918 Compress or expand the audio's dynamic range.
1920 It accepts the following parameters:
1926 A list of times in seconds for each channel over which the instantaneous level
1927 of the input signal is averaged to determine its volume. @var{attacks} refers to
1928 increase of volume and @var{decays} refers to decrease of volume. For most
1929 situations, the attack time (response to the audio getting louder) should be
1930 shorter than the decay time, because the human ear is more sensitive to sudden
1931 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1932 a typical value for decay is 0.8 seconds.
1933 If specified number of attacks & decays is lower than number of channels, the last
1934 set attack/decay will be used for all remaining channels.
1937 A list of points for the transfer function, specified in dB relative to the
1938 maximum possible signal amplitude. Each key points list must be defined using
1939 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1940 @code{x0/y0 x1/y1 x2/y2 ....}
1942 The input values must be in strictly increasing order but the transfer function
1943 does not have to be monotonically rising. The point @code{0/0} is assumed but
1944 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1945 function are @code{-70/-70|-60/-20}.
1948 Set the curve radius in dB for all joints. It defaults to 0.01.
1951 Set the additional gain in dB to be applied at all points on the transfer
1952 function. This allows for easy adjustment of the overall gain.
1956 Set an initial volume, in dB, to be assumed for each channel when filtering
1957 starts. This permits the user to supply a nominal level initially, so that, for
1958 example, a very large gain is not applied to initial signal levels before the
1959 companding has begun to operate. A typical value for audio which is initially
1960 quiet is -90 dB. It defaults to 0.
1963 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1964 delayed before being fed to the volume adjuster. Specifying a delay
1965 approximately equal to the attack/decay times allows the filter to effectively
1966 operate in predictive rather than reactive mode. It defaults to 0.
1970 @subsection Examples
1974 Make music with both quiet and loud passages suitable for listening to in a
1977 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1980 Another example for audio with whisper and explosion parts:
1982 compand=0|0:1|1:-90/-900|-70/-70|-30/-9|0/-3:6:0:0:0
1986 A noise gate for when the noise is at a lower level than the signal:
1988 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1992 Here is another noise gate, this time for when the noise is at a higher level
1993 than the signal (making it, in some ways, similar to squelch):
1995 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1999 2:1 compression starting at -6dB:
2001 compand=points=-80/-80|-6/-6|0/-3.8|20/3.5
2005 2:1 compression starting at -9dB:
2007 compand=points=-80/-80|-9/-9|0/-5.3|20/2.9
2011 2:1 compression starting at -12dB:
2013 compand=points=-80/-80|-12/-12|0/-6.8|20/1.9
2017 2:1 compression starting at -18dB:
2019 compand=points=-80/-80|-18/-18|0/-9.8|20/0.7
2023 3:1 compression starting at -15dB:
2025 compand=points=-80/-80|-15/-15|0/-10.8|20/-5.2
2031 compand=points=-80/-105|-62/-80|-15.4/-15.4|0/-12|20/-7.6
2037 compand=attacks=0:points=-80/-169|-54/-80|-49.5/-64.6|-41.1/-41.1|-25.8/-15|-10.8/-4.5|0/0|20/8.3
2041 Hard limiter at -6dB:
2043 compand=attacks=0:points=-80/-80|-6/-6|20/-6
2047 Hard limiter at -12dB:
2049 compand=attacks=0:points=-80/-80|-12/-12|20/-12
2053 Hard noise gate at -35 dB:
2055 compand=attacks=0:points=-80/-115|-35.1/-80|-35/-35|20/20
2061 compand=attacks=0:points=-80/-80|-12.4/-12.4|-6/-8|0/-6.8|20/-2.8
2065 @section compensationdelay
2067 Compensation Delay Line is a metric based delay to compensate differing
2068 positions of microphones or speakers.
2070 For example, you have recorded guitar with two microphones placed in
2071 different location. Because the front of sound wave has fixed speed in
2072 normal conditions, the phasing of microphones can vary and depends on
2073 their location and interposition. The best sound mix can be achieved when
2074 these microphones are in phase (synchronized). Note that distance of
2075 ~30 cm between microphones makes one microphone to capture signal in
2076 antiphase to another microphone. That makes the final mix sounding moody.
2077 This filter helps to solve phasing problems by adding different delays
2078 to each microphone track and make them synchronized.
2080 The best result can be reached when you take one track as base and
2081 synchronize other tracks one by one with it.
2082 Remember that synchronization/delay tolerance depends on sample rate, too.
2083 Higher sample rates will give more tolerance.
2085 It accepts the following parameters:
2089 Set millimeters distance. This is compensation distance for fine tuning.
2093 Set cm distance. This is compensation distance for tightening distance setup.
2097 Set meters distance. This is compensation distance for hard distance setup.
2101 Set dry amount. Amount of unprocessed (dry) signal.
2105 Set wet amount. Amount of processed (wet) signal.
2109 Set temperature degree in Celsius. This is the temperature of the environment.
2114 Apply a DC shift to the audio.
2116 This can be useful to remove a DC offset (caused perhaps by a hardware problem
2117 in the recording chain) from the audio. The effect of a DC offset is reduced
2118 headroom and hence volume. The @ref{astats} filter can be used to determine if
2119 a signal has a DC offset.
2123 Set the DC shift, allowed range is [-1, 1]. It indicates the amount to shift
2127 Optional. It should have a value much less than 1 (e.g. 0.05 or 0.02) and is
2128 used to prevent clipping.
2132 Dynamic Audio Normalizer.
2134 This filter applies a certain amount of gain to the input audio in order
2135 to bring its peak magnitude to a target level (e.g. 0 dBFS). However, in
2136 contrast to more "simple" normalization algorithms, the Dynamic Audio
2137 Normalizer *dynamically* re-adjusts the gain factor to the input audio.
2138 This allows for applying extra gain to the "quiet" sections of the audio
2139 while avoiding distortions or clipping the "loud" sections. In other words:
2140 The Dynamic Audio Normalizer will "even out" the volume of quiet and loud
2141 sections, in the sense that the volume of each section is brought to the
2142 same target level. Note, however, that the Dynamic Audio Normalizer achieves
2143 this goal *without* applying "dynamic range compressing". It will retain 100%
2144 of the dynamic range *within* each section of the audio file.
2148 Set the frame length in milliseconds. In range from 10 to 8000 milliseconds.
2149 Default is 500 milliseconds.
2150 The Dynamic Audio Normalizer processes the input audio in small chunks,
2151 referred to as frames. This is required, because a peak magnitude has no
2152 meaning for just a single sample value. Instead, we need to determine the
2153 peak magnitude for a contiguous sequence of sample values. While a "standard"
2154 normalizer would simply use the peak magnitude of the complete file, the
2155 Dynamic Audio Normalizer determines the peak magnitude individually for each
2156 frame. The length of a frame is specified in milliseconds. By default, the
2157 Dynamic Audio Normalizer uses a frame length of 500 milliseconds, which has
2158 been found to give good results with most files.
2159 Note that the exact frame length, in number of samples, will be determined
2160 automatically, based on the sampling rate of the individual input audio file.
2163 Set the Gaussian filter window size. In range from 3 to 301, must be odd
2164 number. Default is 31.
2165 Probably the most important parameter of the Dynamic Audio Normalizer is the
2166 @code{window size} of the Gaussian smoothing filter. The filter's window size
2167 is specified in frames, centered around the current frame. For the sake of
2168 simplicity, this must be an odd number. Consequently, the default value of 31
2169 takes into account the current frame, as well as the 15 preceding frames and
2170 the 15 subsequent frames. Using a larger window results in a stronger
2171 smoothing effect and thus in less gain variation, i.e. slower gain
2172 adaptation. Conversely, using a smaller window results in a weaker smoothing
2173 effect and thus in more gain variation, i.e. faster gain adaptation.
2174 In other words, the more you increase this value, the more the Dynamic Audio
2175 Normalizer will behave like a "traditional" normalization filter. On the
2176 contrary, the more you decrease this value, the more the Dynamic Audio
2177 Normalizer will behave like a dynamic range compressor.
2180 Set the target peak value. This specifies the highest permissible magnitude
2181 level for the normalized audio input. This filter will try to approach the
2182 target peak magnitude as closely as possible, but at the same time it also
2183 makes sure that the normalized signal will never exceed the peak magnitude.
2184 A frame's maximum local gain factor is imposed directly by the target peak
2185 magnitude. The default value is 0.95 and thus leaves a headroom of 5%*.
2186 It is not recommended to go above this value.
2189 Set the maximum gain factor. In range from 1.0 to 100.0. Default is 10.0.
2190 The Dynamic Audio Normalizer determines the maximum possible (local) gain
2191 factor for each input frame, i.e. the maximum gain factor that does not
2192 result in clipping or distortion. The maximum gain factor is determined by
2193 the frame's highest magnitude sample. However, the Dynamic Audio Normalizer
2194 additionally bounds the frame's maximum gain factor by a predetermined
2195 (global) maximum gain factor. This is done in order to avoid excessive gain
2196 factors in "silent" or almost silent frames. By default, the maximum gain
2197 factor is 10.0, For most inputs the default value should be sufficient and
2198 it usually is not recommended to increase this value. Though, for input
2199 with an extremely low overall volume level, it may be necessary to allow even
2200 higher gain factors. Note, however, that the Dynamic Audio Normalizer does
2201 not simply apply a "hard" threshold (i.e. cut off values above the threshold).
2202 Instead, a "sigmoid" threshold function will be applied. This way, the
2203 gain factors will smoothly approach the threshold value, but never exceed that
2207 Set the target RMS. In range from 0.0 to 1.0. Default is 0.0 - disabled.
2208 By default, the Dynamic Audio Normalizer performs "peak" normalization.
2209 This means that the maximum local gain factor for each frame is defined
2210 (only) by the frame's highest magnitude sample. This way, the samples can
2211 be amplified as much as possible without exceeding the maximum signal
2212 level, i.e. without clipping. Optionally, however, the Dynamic Audio
2213 Normalizer can also take into account the frame's root mean square,
2214 abbreviated RMS. In electrical engineering, the RMS is commonly used to
2215 determine the power of a time-varying signal. It is therefore considered
2216 that the RMS is a better approximation of the "perceived loudness" than
2217 just looking at the signal's peak magnitude. Consequently, by adjusting all
2218 frames to a constant RMS value, a uniform "perceived loudness" can be
2219 established. If a target RMS value has been specified, a frame's local gain
2220 factor is defined as the factor that would result in exactly that RMS value.
2221 Note, however, that the maximum local gain factor is still restricted by the
2222 frame's highest magnitude sample, in order to prevent clipping.
2225 Enable channels coupling. By default is enabled.
2226 By default, the Dynamic Audio Normalizer will amplify all channels by the same
2227 amount. This means the same gain factor will be applied to all channels, i.e.
2228 the maximum possible gain factor is determined by the "loudest" channel.
2229 However, in some recordings, it may happen that the volume of the different
2230 channels is uneven, e.g. one channel may be "quieter" than the other one(s).
2231 In this case, this option can be used to disable the channel coupling. This way,
2232 the gain factor will be determined independently for each channel, depending
2233 only on the individual channel's highest magnitude sample. This allows for
2234 harmonizing the volume of the different channels.
2237 Enable DC bias correction. By default is disabled.
2238 An audio signal (in the time domain) is a sequence of sample values.
2239 In the Dynamic Audio Normalizer these sample values are represented in the
2240 -1.0 to 1.0 range, regardless of the original input format. Normally, the
2241 audio signal, or "waveform", should be centered around the zero point.
2242 That means if we calculate the mean value of all samples in a file, or in a
2243 single frame, then the result should be 0.0 or at least very close to that
2244 value. If, however, there is a significant deviation of the mean value from
2245 0.0, in either positive or negative direction, this is referred to as a
2246 DC bias or DC offset. Since a DC bias is clearly undesirable, the Dynamic
2247 Audio Normalizer provides optional DC bias correction.
2248 With DC bias correction enabled, the Dynamic Audio Normalizer will determine
2249 the mean value, or "DC correction" offset, of each input frame and subtract
2250 that value from all of the frame's sample values which ensures those samples
2251 are centered around 0.0 again. Also, in order to avoid "gaps" at the frame
2252 boundaries, the DC correction offset values will be interpolated smoothly
2253 between neighbouring frames.
2256 Enable alternative boundary mode. By default is disabled.
2257 The Dynamic Audio Normalizer takes into account a certain neighbourhood
2258 around each frame. This includes the preceding frames as well as the
2259 subsequent frames. However, for the "boundary" frames, located at the very
2260 beginning and at the very end of the audio file, not all neighbouring
2261 frames are available. In particular, for the first few frames in the audio
2262 file, the preceding frames are not known. And, similarly, for the last few
2263 frames in the audio file, the subsequent frames are not known. Thus, the
2264 question arises which gain factors should be assumed for the missing frames
2265 in the "boundary" region. The Dynamic Audio Normalizer implements two modes
2266 to deal with this situation. The default boundary mode assumes a gain factor
2267 of exactly 1.0 for the missing frames, resulting in a smooth "fade in" and
2268 "fade out" at the beginning and at the end of the input, respectively.
2271 Set the compress factor. In range from 0.0 to 30.0. Default is 0.0.
2272 By default, the Dynamic Audio Normalizer does not apply "traditional"
2273 compression. This means that signal peaks will not be pruned and thus the
2274 full dynamic range will be retained within each local neighbourhood. However,
2275 in some cases it may be desirable to combine the Dynamic Audio Normalizer's
2276 normalization algorithm with a more "traditional" compression.
2277 For this purpose, the Dynamic Audio Normalizer provides an optional compression
2278 (thresholding) function. If (and only if) the compression feature is enabled,
2279 all input frames will be processed by a soft knee thresholding function prior
2280 to the actual normalization process. Put simply, the thresholding function is
2281 going to prune all samples whose magnitude exceeds a certain threshold value.
2282 However, the Dynamic Audio Normalizer does not simply apply a fixed threshold
2283 value. Instead, the threshold value will be adjusted for each individual
2285 In general, smaller parameters result in stronger compression, and vice versa.
2286 Values below 3.0 are not recommended, because audible distortion may appear.
2291 Make audio easier to listen to on headphones.
2293 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
2294 so that when listened to on headphones the stereo image is moved from
2295 inside your head (standard for headphones) to outside and in front of
2296 the listener (standard for speakers).
2302 Apply a two-pole peaking equalisation (EQ) filter. With this
2303 filter, the signal-level at and around a selected frequency can
2304 be increased or decreased, whilst (unlike bandpass and bandreject
2305 filters) that at all other frequencies is unchanged.
2307 In order to produce complex equalisation curves, this filter can
2308 be given several times, each with a different central frequency.
2310 The filter accepts the following options:
2314 Set the filter's central frequency in Hz.
2317 Set method to specify band-width of filter.
2330 Specify the band-width of a filter in width_type units.
2333 Set the required gain or attenuation in dB.
2334 Beware of clipping when using a positive gain.
2337 @subsection Examples
2340 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
2342 equalizer=f=1000:width_type=h:width=200:g=-10
2346 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
2348 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
2352 @section extrastereo
2354 Linearly increases the difference between left and right channels which
2355 adds some sort of "live" effect to playback.
2357 The filter accepts the following option:
2361 Sets the difference coefficient (default: 2.5). 0.0 means mono sound
2362 (average of both channels), with 1.0 sound will be unchanged, with
2363 -1.0 left and right channels will be swapped.
2366 Enable clipping. By default is enabled.
2369 @section firequalizer
2370 Apply FIR Equalization using arbitrary frequency response.
2372 The filter accepts the following option:
2376 Set gain curve equation (in dB). The expression can contain variables:
2379 the evaluated frequency
2383 channel number, set to 0 when multichannels evaluation is disabled
2385 channel id, see libavutil/channel_layout.h, set to the first channel id when
2386 multichannels evaluation is disabled
2390 channel_layout, see libavutil/channel_layout.h
2395 @item gain_interpolate(f)
2396 interpolate gain on frequency f based on gain_entry
2398 This option is also available as command. Default is @code{gain_interpolate(f)}.
2401 Set gain entry for gain_interpolate function. The expression can
2405 store gain entry at frequency f with value g
2407 This option is also available as command.
2410 Set filter delay in seconds. Higher value means more accurate.
2411 Default is @code{0.01}.
2414 Set filter accuracy in Hz. Lower value means more accurate.
2415 Default is @code{5}.
2418 Set window function. Acceptable values are:
2421 rectangular window, useful when gain curve is already smooth
2423 hann window (default)
2429 3-terms continuous 1st derivative nuttall window
2431 minimum 3-terms discontinuous nuttall window
2433 4-terms continuous 1st derivative nuttall window
2435 minimum 4-terms discontinuous nuttall (blackman-nuttall) window
2437 blackman-harris window
2441 If enabled, use fixed number of audio samples. This improves speed when
2442 filtering with large delay. Default is disabled.
2445 Enable multichannels evaluation on gain. Default is disabled.
2448 @subsection Examples
2453 firequalizer=gain='if(lt(f,1000), 0, -INF)'
2456 lowpass at 1000 Hz with gain_entry:
2458 firequalizer=gain_entry='entry(1000,0); entry(1001, -INF)'
2461 custom equalization:
2463 firequalizer=gain_entry='entry(100,0); entry(400, -4); entry(1000, -6); entry(2000, 0)'
2468 firequalizer=delay=0.1:fixed=on
2471 lowpass on left channel, highpass on right channel:
2473 firequalizer=gain='if(eq(chid,1), gain_interpolate(f), if(eq(chid,2), gain_interpolate(1e6+f), 0))'
2474 :gain_entry='entry(1000, 0); entry(1001,-INF); entry(1e6+1000,0)':multi=on
2479 Apply a flanging effect to the audio.
2481 The filter accepts the following options:
2485 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
2488 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
2491 Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
2495 Set percentage of delayed signal mixed with original. Range from 0 to 100.
2496 Default value is 71.
2499 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
2502 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
2503 Default value is @var{sinusoidal}.
2506 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
2507 Default value is 25.
2510 Set delay-line interpolation, @var{linear} or @var{quadratic}.
2511 Default is @var{linear}.
2516 Apply a high-pass filter with 3dB point frequency.
2517 The filter can be either single-pole, or double-pole (the default).
2518 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2520 The filter accepts the following options:
2524 Set frequency in Hz. Default is 3000.
2527 Set number of poles. Default is 2.
2530 Set method to specify band-width of filter.
2543 Specify the band-width of a filter in width_type units.
2544 Applies only to double-pole filter.
2545 The default is 0.707q and gives a Butterworth response.
2550 Join multiple input streams into one multi-channel stream.
2552 It accepts the following parameters:
2556 The number of input streams. It defaults to 2.
2558 @item channel_layout
2559 The desired output channel layout. It defaults to stereo.
2562 Map channels from inputs to output. The argument is a '|'-separated list of
2563 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
2564 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
2565 can be either the name of the input channel (e.g. FL for front left) or its
2566 index in the specified input stream. @var{out_channel} is the name of the output
2570 The filter will attempt to guess the mappings when they are not specified
2571 explicitly. It does so by first trying to find an unused matching input channel
2572 and if that fails it picks the first unused input channel.
2574 Join 3 inputs (with properly set channel layouts):
2576 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
2579 Build a 5.1 output from 6 single-channel streams:
2581 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
2582 'join=inputs=6:channel_layout=5.1:map=0.0-FL|1.0-FR|2.0-FC|3.0-SL|4.0-SR|5.0-LFE'
2588 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
2590 To enable compilation of this filter you need to configure FFmpeg with
2591 @code{--enable-ladspa}.
2595 Specifies the name of LADSPA plugin library to load. If the environment
2596 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
2597 each one of the directories specified by the colon separated list in
2598 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
2599 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
2600 @file{/usr/lib/ladspa/}.
2603 Specifies the plugin within the library. Some libraries contain only
2604 one plugin, but others contain many of them. If this is not set filter
2605 will list all available plugins within the specified library.
2608 Set the '|' separated list of controls which are zero or more floating point
2609 values that determine the behavior of the loaded plugin (for example delay,
2611 Controls need to be defined using the following syntax:
2612 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
2613 @var{valuei} is the value set on the @var{i}-th control.
2614 Alternatively they can be also defined using the following syntax:
2615 @var{value0}|@var{value1}|@var{value2}|..., where
2616 @var{valuei} is the value set on the @var{i}-th control.
2617 If @option{controls} is set to @code{help}, all available controls and
2618 their valid ranges are printed.
2620 @item sample_rate, s
2621 Specify the sample rate, default to 44100. Only used if plugin have
2625 Set the number of samples per channel per each output frame, default
2626 is 1024. Only used if plugin have zero inputs.
2629 Set the minimum duration of the sourced audio. See
2630 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2631 for the accepted syntax.
2632 Note that the resulting duration may be greater than the specified duration,
2633 as the generated audio is always cut at the end of a complete frame.
2634 If not specified, or the expressed duration is negative, the audio is
2635 supposed to be generated forever.
2636 Only used if plugin have zero inputs.
2640 @subsection Examples
2644 List all available plugins within amp (LADSPA example plugin) library:
2650 List all available controls and their valid ranges for @code{vcf_notch}
2651 plugin from @code{VCF} library:
2653 ladspa=f=vcf:p=vcf_notch:c=help
2657 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
2660 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
2664 Add reverberation to the audio using TAP-plugins
2665 (Tom's Audio Processing plugins):
2667 ladspa=file=tap_reverb:tap_reverb
2671 Generate white noise, with 0.2 amplitude:
2673 ladspa=file=cmt:noise_source_white:c=c0=.2
2677 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
2678 @code{C* Audio Plugin Suite} (CAPS) library:
2680 ladspa=file=caps:Click:c=c1=20'
2684 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
2686 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
2690 Increase volume by 20dB using fast lookahead limiter from Steve Harris
2691 @code{SWH Plugins} collection:
2693 ladspa=fast_lookahead_limiter_1913:fastLookaheadLimiter:20|0|2
2697 Attenuate low frequencies using Multiband EQ from Steve Harris
2698 @code{SWH Plugins} collection:
2700 ladspa=mbeq_1197:mbeq:-24|-24|-24|0|0|0|0|0|0|0|0|0|0|0|0
2704 @subsection Commands
2706 This filter supports the following commands:
2709 Modify the @var{N}-th control value.
2711 If the specified value is not valid, it is ignored and prior one is kept.
2716 Apply a low-pass filter with 3dB point frequency.
2717 The filter can be either single-pole or double-pole (the default).
2718 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2720 The filter accepts the following options:
2724 Set frequency in Hz. Default is 500.
2727 Set number of poles. Default is 2.
2730 Set method to specify band-width of filter.
2743 Specify the band-width of a filter in width_type units.
2744 Applies only to double-pole filter.
2745 The default is 0.707q and gives a Butterworth response.
2751 Mix channels with specific gain levels. The filter accepts the output
2752 channel layout followed by a set of channels definitions.
2754 This filter is also designed to efficiently remap the channels of an audio
2757 The filter accepts parameters of the form:
2758 "@var{l}|@var{outdef}|@var{outdef}|..."
2762 output channel layout or number of channels
2765 output channel specification, of the form:
2766 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
2769 output channel to define, either a channel name (FL, FR, etc.) or a channel
2770 number (c0, c1, etc.)
2773 multiplicative coefficient for the channel, 1 leaving the volume unchanged
2776 input channel to use, see out_name for details; it is not possible to mix
2777 named and numbered input channels
2780 If the `=' in a channel specification is replaced by `<', then the gains for
2781 that specification will be renormalized so that the total is 1, thus
2782 avoiding clipping noise.
2784 @subsection Mixing examples
2786 For example, if you want to down-mix from stereo to mono, but with a bigger
2787 factor for the left channel:
2789 pan=1c|c0=0.9*c0+0.1*c1
2792 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
2793 7-channels surround:
2795 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
2798 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
2799 that should be preferred (see "-ac" option) unless you have very specific
2802 @subsection Remapping examples
2804 The channel remapping will be effective if, and only if:
2807 @item gain coefficients are zeroes or ones,
2808 @item only one input per channel output,
2811 If all these conditions are satisfied, the filter will notify the user ("Pure
2812 channel mapping detected"), and use an optimized and lossless method to do the
2815 For example, if you have a 5.1 source and want a stereo audio stream by
2816 dropping the extra channels:
2818 pan="stereo| c0=FL | c1=FR"
2821 Given the same source, you can also switch front left and front right channels
2822 and keep the input channel layout:
2824 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
2827 If the input is a stereo audio stream, you can mute the front left channel (and
2828 still keep the stereo channel layout) with:
2833 Still with a stereo audio stream input, you can copy the right channel in both
2834 front left and right:
2836 pan="stereo| c0=FR | c1=FR"
2841 ReplayGain scanner filter. This filter takes an audio stream as an input and
2842 outputs it unchanged.
2843 At end of filtering it displays @code{track_gain} and @code{track_peak}.
2847 Convert the audio sample format, sample rate and channel layout. It is
2848 not meant to be used directly.
2851 Apply time-stretching and pitch-shifting with librubberband.
2853 The filter accepts the following options:
2857 Set tempo scale factor.
2860 Set pitch scale factor.
2863 Set transients detector.
2864 Possible values are:
2873 Possible values are:
2882 Possible values are:
2889 Set processing window size.
2890 Possible values are:
2899 Possible values are:
2906 Enable formant preservation when shift pitching.
2907 Possible values are:
2915 Possible values are:
2924 Possible values are:
2931 @section sidechaincompress
2933 This filter acts like normal compressor but has the ability to compress
2934 detected signal using second input signal.
2935 It needs two input streams and returns one output stream.
2936 First input stream will be processed depending on second stream signal.
2937 The filtered signal then can be filtered with other filters in later stages of
2938 processing. See @ref{pan} and @ref{amerge} filter.
2940 The filter accepts the following options:
2944 Set input gain. Default is 1. Range is between 0.015625 and 64.
2947 If a signal of second stream raises above this level it will affect the gain
2948 reduction of first stream.
2949 By default is 0.125. Range is between 0.00097563 and 1.
2952 Set a ratio about which the signal is reduced. 1:2 means that if the level
2953 raised 4dB above the threshold, it will be only 2dB above after the reduction.
2954 Default is 2. Range is between 1 and 20.
2957 Amount of milliseconds the signal has to rise above the threshold before gain
2958 reduction starts. Default is 20. Range is between 0.01 and 2000.
2961 Amount of milliseconds the signal has to fall below the threshold before
2962 reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
2965 Set the amount by how much signal will be amplified after processing.
2966 Default is 2. Range is from 1 and 64.
2969 Curve the sharp knee around the threshold to enter gain reduction more softly.
2970 Default is 2.82843. Range is between 1 and 8.
2973 Choose if the @code{average} level between all channels of side-chain stream
2974 or the louder(@code{maximum}) channel of side-chain stream affects the
2975 reduction. Default is @code{average}.
2978 Should the exact signal be taken in case of @code{peak} or an RMS one in case
2979 of @code{rms}. Default is @code{rms} which is mainly smoother.
2982 Set sidechain gain. Default is 1. Range is between 0.015625 and 64.
2985 How much to use compressed signal in output. Default is 1.
2986 Range is between 0 and 1.
2989 @subsection Examples
2993 Full ffmpeg example taking 2 audio inputs, 1st input to be compressed
2994 depending on the signal of 2nd input and later compressed signal to be
2995 merged with 2nd input:
2997 ffmpeg -i main.flac -i sidechain.flac -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress[compr];[compr][mix]amerge"
3001 @section sidechaingate
3003 A sidechain gate acts like a normal (wideband) gate but has the ability to
3004 filter the detected signal before sending it to the gain reduction stage.
3005 Normally a gate uses the full range signal to detect a level above the
3007 For example: If you cut all lower frequencies from your sidechain signal
3008 the gate will decrease the volume of your track only if not enough highs
3009 appear. With this technique you are able to reduce the resonation of a
3010 natural drum or remove "rumbling" of muted strokes from a heavily distorted
3012 It needs two input streams and returns one output stream.
3013 First input stream will be processed depending on second stream signal.
3015 The filter accepts the following options:
3019 Set input level before filtering.
3020 Default is 1. Allowed range is from 0.015625 to 64.
3023 Set the level of gain reduction when the signal is below the threshold.
3024 Default is 0.06125. Allowed range is from 0 to 1.
3027 If a signal rises above this level the gain reduction is released.
3028 Default is 0.125. Allowed range is from 0 to 1.
3031 Set a ratio about which the signal is reduced.
3032 Default is 2. Allowed range is from 1 to 9000.
3035 Amount of milliseconds the signal has to rise above the threshold before gain
3037 Default is 20 milliseconds. Allowed range is from 0.01 to 9000.
3040 Amount of milliseconds the signal has to fall below the threshold before the
3041 reduction is increased again. Default is 250 milliseconds.
3042 Allowed range is from 0.01 to 9000.
3045 Set amount of amplification of signal after processing.
3046 Default is 1. Allowed range is from 1 to 64.
3049 Curve the sharp knee around the threshold to enter gain reduction more softly.
3050 Default is 2.828427125. Allowed range is from 1 to 8.
3053 Choose if exact signal should be taken for detection or an RMS like one.
3054 Default is rms. Can be peak or rms.
3057 Choose if the average level between all channels or the louder channel affects
3059 Default is average. Can be average or maximum.
3062 Set sidechain gain. Default is 1. Range is from 0.015625 to 64.
3065 @section silencedetect
3067 Detect silence in an audio stream.
3069 This filter logs a message when it detects that the input audio volume is less
3070 or equal to a noise tolerance value for a duration greater or equal to the
3071 minimum detected noise duration.
3073 The printed times and duration are expressed in seconds.
3075 The filter accepts the following options:
3079 Set silence duration until notification (default is 2 seconds).
3082 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
3083 specified value) or amplitude ratio. Default is -60dB, or 0.001.
3086 @subsection Examples
3090 Detect 5 seconds of silence with -50dB noise tolerance:
3092 silencedetect=n=-50dB:d=5
3096 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
3097 tolerance in @file{silence.mp3}:
3099 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
3103 @section silenceremove
3105 Remove silence from the beginning, middle or end of the audio.
3107 The filter accepts the following options:
3111 This value is used to indicate if audio should be trimmed at beginning of
3112 the audio. A value of zero indicates no silence should be trimmed from the
3113 beginning. When specifying a non-zero value, it trims audio up until it
3114 finds non-silence. Normally, when trimming silence from beginning of audio
3115 the @var{start_periods} will be @code{1} but it can be increased to higher
3116 values to trim all audio up to specific count of non-silence periods.
3117 Default value is @code{0}.
3119 @item start_duration
3120 Specify the amount of time that non-silence must be detected before it stops
3121 trimming audio. By increasing the duration, bursts of noises can be treated
3122 as silence and trimmed off. Default value is @code{0}.
3124 @item start_threshold
3125 This indicates what sample value should be treated as silence. For digital
3126 audio, a value of @code{0} may be fine but for audio recorded from analog,
3127 you may wish to increase the value to account for background noise.
3128 Can be specified in dB (in case "dB" is appended to the specified value)
3129 or amplitude ratio. Default value is @code{0}.
3132 Set the count for trimming silence from the end of audio.
3133 To remove silence from the middle of a file, specify a @var{stop_periods}
3134 that is negative. This value is then treated as a positive value and is
3135 used to indicate the effect should restart processing as specified by
3136 @var{start_periods}, making it suitable for removing periods of silence
3137 in the middle of the audio.
3138 Default value is @code{0}.
3141 Specify a duration of silence that must exist before audio is not copied any
3142 more. By specifying a higher duration, silence that is wanted can be left in
3144 Default value is @code{0}.
3146 @item stop_threshold
3147 This is the same as @option{start_threshold} but for trimming silence from
3149 Can be specified in dB (in case "dB" is appended to the specified value)
3150 or amplitude ratio. Default value is @code{0}.
3153 This indicate that @var{stop_duration} length of audio should be left intact
3154 at the beginning of each period of silence.
3155 For example, if you want to remove long pauses between words but do not want
3156 to remove the pauses completely. Default value is @code{0}.
3159 Set how is silence detected. Can be @code{rms} or @code{peak}. Second is faster
3160 and works better with digital silence which is exactly 0.
3161 Default value is @code{rms}.
3164 Set ratio used to calculate size of window for detecting silence.
3165 Default value is @code{0.02}. Allowed range is from @code{0} to @code{10}.
3168 @subsection Examples
3172 The following example shows how this filter can be used to start a recording
3173 that does not contain the delay at the start which usually occurs between
3174 pressing the record button and the start of the performance:
3176 silenceremove=1:5:0.02
3180 Trim all silence encountered from begining to end where there is more than 1
3181 second of silence in audio:
3183 silenceremove=0:0:0:-1:1:-90dB
3189 SOFAlizer uses head-related transfer functions (HRTFs) to create virtual
3190 loudspeakers around the user for binaural listening via headphones (audio
3191 formats up to 9 channels supported).
3192 The HRTFs are stored in SOFA files (see @url{http://www.sofacoustics.org/} for a database).
3193 SOFAlizer is developed at the Acoustics Research Institute (ARI) of the
3194 Austrian Academy of Sciences.
3196 To enable compilation of this filter you need to configure FFmpeg with
3197 @code{--enable-netcdf}.
3199 The filter accepts the following options:
3203 Set the SOFA file used for rendering.
3206 Set gain applied to audio. Value is in dB. Default is 0.
3209 Set rotation of virtual loudspeakers in deg. Default is 0.
3212 Set elevation of virtual speakers in deg. Default is 0.
3215 Set distance in meters between loudspeakers and the listener with near-field
3216 HRTFs. Default is 1.
3219 Set processing type. Can be @var{time} or @var{freq}. @var{time} is
3220 processing audio in time domain which is slow.
3221 @var{freq} is processing audio in frequency domain which is fast.
3222 Default is @var{freq}.
3225 Set custom positions of virtual loudspeakers. Syntax for this option is:
3226 <CH> <AZIM> <ELEV>[|<CH> <AZIM> <ELEV>|...].
3227 Each virtual loudspeaker is described with short channel name following with
3228 azimuth and elevation in degreees.
3229 Each virtual loudspeaker description is separated by '|'.
3230 For example to override front left and front right channel positions use:
3231 'speakers=FL 45 15|FR 345 15'.
3232 Descriptions with unrecognised channel names are ignored.
3235 @subsection Examples
3239 Using ClubFritz6 sofa file:
3241 sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=1
3245 Using ClubFritz12 sofa file and bigger radius with small rotation:
3247 sofalizer=sofa=/path/to/ClubFritz12.sofa:type=freq:radius=2:rotation=5
3251 Similar as above but with custom speaker positions for front left, front right, rear left and rear right
3252 and also with custom gain:
3254 "sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=2:speakers=FL 45|FR 315|RL 135|RR 225:gain=28"
3258 @section stereotools
3260 This filter has some handy utilities to manage stereo signals, for converting
3261 M/S stereo recordings to L/R signal while having control over the parameters
3262 or spreading the stereo image of master track.
3264 The filter accepts the following options:
3268 Set input level before filtering for both channels. Defaults is 1.
3269 Allowed range is from 0.015625 to 64.
3272 Set output level after filtering for both channels. Defaults is 1.
3273 Allowed range is from 0.015625 to 64.
3276 Set input balance between both channels. Default is 0.
3277 Allowed range is from -1 to 1.
3280 Set output balance between both channels. Default is 0.
3281 Allowed range is from -1 to 1.
3284 Enable softclipping. Results in analog distortion instead of harsh digital 0dB
3285 clipping. Disabled by default.
3288 Mute the left channel. Disabled by default.
3291 Mute the right channel. Disabled by default.
3294 Change the phase of the left channel. Disabled by default.
3297 Change the phase of the right channel. Disabled by default.
3300 Set stereo mode. Available values are:
3304 Left/Right to Left/Right, this is default.
3307 Left/Right to Mid/Side.
3310 Mid/Side to Left/Right.
3313 Left/Right to Left/Left.
3316 Left/Right to Right/Right.
3319 Left/Right to Left + Right.
3322 Left/Right to Right/Left.
3326 Set level of side signal. Default is 1.
3327 Allowed range is from 0.015625 to 64.
3330 Set balance of side signal. Default is 0.
3331 Allowed range is from -1 to 1.
3334 Set level of the middle signal. Default is 1.
3335 Allowed range is from 0.015625 to 64.
3338 Set middle signal pan. Default is 0. Allowed range is from -1 to 1.
3341 Set stereo base between mono and inversed channels. Default is 0.
3342 Allowed range is from -1 to 1.
3345 Set delay in milliseconds how much to delay left from right channel and
3346 vice versa. Default is 0. Allowed range is from -20 to 20.
3349 Set S/C level. Default is 1. Allowed range is from 1 to 100.
3352 Set the stereo phase in degrees. Default is 0. Allowed range is from 0 to 360.
3355 @subsection Examples
3359 Apply karaoke like effect:
3361 stereotools=mlev=0.015625
3365 Convert M/S signal to L/R:
3367 "stereotools=mode=ms>lr"
3371 @section stereowiden
3373 This filter enhance the stereo effect by suppressing signal common to both
3374 channels and by delaying the signal of left into right and vice versa,
3375 thereby widening the stereo effect.
3377 The filter accepts the following options:
3381 Time in milliseconds of the delay of left signal into right and vice versa.
3382 Default is 20 milliseconds.
3385 Amount of gain in delayed signal into right and vice versa. Gives a delay
3386 effect of left signal in right output and vice versa which gives widening
3387 effect. Default is 0.3.
3390 Cross feed of left into right with inverted phase. This helps in suppressing
3391 the mono. If the value is 1 it will cancel all the signal common to both
3392 channels. Default is 0.3.
3395 Set level of input signal of original channel. Default is 0.8.
3400 Use the NVIDIA Performance Primitives (libnpp) to perform scaling and/or pixel
3401 format conversion on CUDA video frames. Setting the output width and height
3402 works in the same way as for the @var{scale} filter.
3404 The following additional options are accepted:
3407 The pixel format of the output CUDA frames. If set to the string "same" (the
3408 default), the input format will be kept. Note that automatic format negotiation
3409 and conversion is not yet supported for hardware frames
3412 The interpolation algorithm used for resizing. One of the following:
3419 @item cubic2p_bspline
3420 2-parameter cubic (B=1, C=0)
3422 @item cubic2p_catmullrom
3423 2-parameter cubic (B=0, C=1/2)
3425 @item cubic2p_b05c03
3426 2-parameter cubic (B=1/2, C=3/10)
3437 Select frames to pass in output.
3441 Boost or cut treble (upper) frequencies of the audio using a two-pole
3442 shelving filter with a response similar to that of a standard
3443 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
3445 The filter accepts the following options:
3449 Give the gain at whichever is the lower of ~22 kHz and the
3450 Nyquist frequency. Its useful range is about -20 (for a large cut)
3451 to +20 (for a large boost). Beware of clipping when using a positive gain.
3454 Set the filter's central frequency and so can be used
3455 to extend or reduce the frequency range to be boosted or cut.
3456 The default value is @code{3000} Hz.
3459 Set method to specify band-width of filter.
3472 Determine how steep is the filter's shelf transition.
3477 Sinusoidal amplitude modulation.
3479 The filter accepts the following options:
3483 Modulation frequency in Hertz. Modulation frequencies in the subharmonic range
3484 (20 Hz or lower) will result in a tremolo effect.
3485 This filter may also be used as a ring modulator by specifying
3486 a modulation frequency higher than 20 Hz.
3487 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
3490 Depth of modulation as a percentage. Range is 0.0 - 1.0.
3491 Default value is 0.5.
3496 Sinusoidal phase modulation.
3498 The filter accepts the following options:
3502 Modulation frequency in Hertz.
3503 Range is 0.1 - 20000.0. Default value is 5.0 Hz.
3506 Depth of modulation as a percentage. Range is 0.0 - 1.0.
3507 Default value is 0.5.
3512 Adjust the input audio volume.
3514 It accepts the following parameters:
3518 Set audio volume expression.
3520 Output values are clipped to the maximum value.
3522 The output audio volume is given by the relation:
3524 @var{output_volume} = @var{volume} * @var{input_volume}
3527 The default value for @var{volume} is "1.0".
3530 This parameter represents the mathematical precision.
3532 It determines which input sample formats will be allowed, which affects the
3533 precision of the volume scaling.
3537 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
3539 32-bit floating-point; this limits input sample format to FLT. (default)
3541 64-bit floating-point; this limits input sample format to DBL.
3545 Choose the behaviour on encountering ReplayGain side data in input frames.
3549 Remove ReplayGain side data, ignoring its contents (the default).
3552 Ignore ReplayGain side data, but leave it in the frame.
3555 Prefer the track gain, if present.
3558 Prefer the album gain, if present.
3561 @item replaygain_preamp
3562 Pre-amplification gain in dB to apply to the selected replaygain gain.
3564 Default value for @var{replaygain_preamp} is 0.0.
3567 Set when the volume expression is evaluated.
3569 It accepts the following values:
3572 only evaluate expression once during the filter initialization, or
3573 when the @samp{volume} command is sent
3576 evaluate expression for each incoming frame
3579 Default value is @samp{once}.
3582 The volume expression can contain the following parameters.
3586 frame number (starting at zero)
3589 @item nb_consumed_samples
3590 number of samples consumed by the filter
3592 number of samples in the current frame
3594 original frame position in the file
3600 PTS at start of stream
3602 time at start of stream
3608 last set volume value
3611 Note that when @option{eval} is set to @samp{once} only the
3612 @var{sample_rate} and @var{tb} variables are available, all other
3613 variables will evaluate to NAN.
3615 @subsection Commands
3617 This filter supports the following commands:
3620 Modify the volume expression.
3621 The command accepts the same syntax of the corresponding option.
3623 If the specified expression is not valid, it is kept at its current
3625 @item replaygain_noclip
3626 Prevent clipping by limiting the gain applied.
3628 Default value for @var{replaygain_noclip} is 1.
3632 @subsection Examples
3636 Halve the input audio volume:
3640 volume=volume=-6.0206dB
3643 In all the above example the named key for @option{volume} can be
3644 omitted, for example like in:
3650 Increase input audio power by 6 decibels using fixed-point precision:
3652 volume=volume=6dB:precision=fixed
3656 Fade volume after time 10 with an annihilation period of 5 seconds:
3658 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
3662 @section volumedetect
3664 Detect the volume of the input video.
3666 The filter has no parameters. The input is not modified. Statistics about
3667 the volume will be printed in the log when the input stream end is reached.
3669 In particular it will show the mean volume (root mean square), maximum
3670 volume (on a per-sample basis), and the beginning of a histogram of the
3671 registered volume values (from the maximum value to a cumulated 1/1000 of
3674 All volumes are in decibels relative to the maximum PCM value.
3676 @subsection Examples
3678 Here is an excerpt of the output:
3680 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
3681 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
3682 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
3683 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
3684 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
3685 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
3686 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
3687 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
3688 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
3694 The mean square energy is approximately -27 dB, or 10^-2.7.
3696 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
3698 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
3701 In other words, raising the volume by +4 dB does not cause any clipping,
3702 raising it by +5 dB causes clipping for 6 samples, etc.
3704 @c man end AUDIO FILTERS
3706 @chapter Audio Sources
3707 @c man begin AUDIO SOURCES
3709 Below is a description of the currently available audio sources.
3713 Buffer audio frames, and make them available to the filter chain.
3715 This source is mainly intended for a programmatic use, in particular
3716 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
3718 It accepts the following parameters:
3722 The timebase which will be used for timestamps of submitted frames. It must be
3723 either a floating-point number or in @var{numerator}/@var{denominator} form.
3726 The sample rate of the incoming audio buffers.
3729 The sample format of the incoming audio buffers.
3730 Either a sample format name or its corresponding integer representation from
3731 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
3733 @item channel_layout
3734 The channel layout of the incoming audio buffers.
3735 Either a channel layout name from channel_layout_map in
3736 @file{libavutil/channel_layout.c} or its corresponding integer representation
3737 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
3740 The number of channels of the incoming audio buffers.
3741 If both @var{channels} and @var{channel_layout} are specified, then they
3746 @subsection Examples
3749 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
3752 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
3753 Since the sample format with name "s16p" corresponds to the number
3754 6 and the "stereo" channel layout corresponds to the value 0x3, this is
3757 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
3762 Generate an audio signal specified by an expression.
3764 This source accepts in input one or more expressions (one for each
3765 channel), which are evaluated and used to generate a corresponding
3768 This source accepts the following options:
3772 Set the '|'-separated expressions list for each separate channel. In case the
3773 @option{channel_layout} option is not specified, the selected channel layout
3774 depends on the number of provided expressions. Otherwise the last
3775 specified expression is applied to the remaining output channels.
3777 @item channel_layout, c
3778 Set the channel layout. The number of channels in the specified layout
3779 must be equal to the number of specified expressions.
3782 Set the minimum duration of the sourced audio. See
3783 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
3784 for the accepted syntax.
3785 Note that the resulting duration may be greater than the specified
3786 duration, as the generated audio is always cut at the end of a
3789 If not specified, or the expressed duration is negative, the audio is
3790 supposed to be generated forever.
3793 Set the number of samples per channel per each output frame,
3796 @item sample_rate, s
3797 Specify the sample rate, default to 44100.
3800 Each expression in @var{exprs} can contain the following constants:
3804 number of the evaluated sample, starting from 0
3807 time of the evaluated sample expressed in seconds, starting from 0
3814 @subsection Examples
3824 Generate a sin signal with frequency of 440 Hz, set sample rate to
3827 aevalsrc="sin(440*2*PI*t):s=8000"
3831 Generate a two channels signal, specify the channel layout (Front
3832 Center + Back Center) explicitly:
3834 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
3838 Generate white noise:
3840 aevalsrc="-2+random(0)"
3844 Generate an amplitude modulated signal:
3846 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
3850 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
3852 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
3859 The null audio source, return unprocessed audio frames. It is mainly useful
3860 as a template and to be employed in analysis / debugging tools, or as
3861 the source for filters which ignore the input data (for example the sox
3864 This source accepts the following options:
3868 @item channel_layout, cl
3870 Specifies the channel layout, and can be either an integer or a string
3871 representing a channel layout. The default value of @var{channel_layout}
3874 Check the channel_layout_map definition in
3875 @file{libavutil/channel_layout.c} for the mapping between strings and
3876 channel layout values.
3878 @item sample_rate, r
3879 Specifies the sample rate, and defaults to 44100.
3882 Set the number of samples per requested frames.
3886 @subsection Examples
3890 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
3892 anullsrc=r=48000:cl=4
3896 Do the same operation with a more obvious syntax:
3898 anullsrc=r=48000:cl=mono
3902 All the parameters need to be explicitly defined.
3906 Synthesize a voice utterance using the libflite library.
3908 To enable compilation of this filter you need to configure FFmpeg with
3909 @code{--enable-libflite}.
3911 Note that the flite library is not thread-safe.
3913 The filter accepts the following options:
3918 If set to 1, list the names of the available voices and exit
3919 immediately. Default value is 0.
3922 Set the maximum number of samples per frame. Default value is 512.
3925 Set the filename containing the text to speak.
3928 Set the text to speak.
3931 Set the voice to use for the speech synthesis. Default value is
3932 @code{kal}. See also the @var{list_voices} option.
3935 @subsection Examples
3939 Read from file @file{speech.txt}, and synthesize the text using the
3940 standard flite voice:
3942 flite=textfile=speech.txt
3946 Read the specified text selecting the @code{slt} voice:
3948 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
3952 Input text to ffmpeg:
3954 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
3958 Make @file{ffplay} speak the specified text, using @code{flite} and
3959 the @code{lavfi} device:
3961 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
3965 For more information about libflite, check:
3966 @url{http://www.speech.cs.cmu.edu/flite/}
3970 Generate a noise audio signal.
3972 The filter accepts the following options:
3975 @item sample_rate, r
3976 Specify the sample rate. Default value is 48000 Hz.
3979 Specify the amplitude (0.0 - 1.0) of the generated audio stream. Default value
3983 Specify the duration of the generated audio stream. Not specifying this option
3984 results in noise with an infinite length.
3986 @item color, colour, c
3987 Specify the color of noise. Available noise colors are white, pink, and brown.
3988 Default color is white.
3991 Specify a value used to seed the PRNG.
3994 Set the number of samples per each output frame, default is 1024.
3997 @subsection Examples
4002 Generate 60 seconds of pink noise, with a 44.1 kHz sampling rate and an amplitude of 0.5:
4004 anoisesrc=d=60:c=pink:r=44100:a=0.5
4010 Generate an audio signal made of a sine wave with amplitude 1/8.
4012 The audio signal is bit-exact.
4014 The filter accepts the following options:
4019 Set the carrier frequency. Default is 440 Hz.
4021 @item beep_factor, b
4022 Enable a periodic beep every second with frequency @var{beep_factor} times
4023 the carrier frequency. Default is 0, meaning the beep is disabled.
4025 @item sample_rate, r
4026 Specify the sample rate, default is 44100.
4029 Specify the duration of the generated audio stream.
4031 @item samples_per_frame
4032 Set the number of samples per output frame.
4034 The expression can contain the following constants:
4038 The (sequential) number of the output audio frame, starting from 0.
4041 The PTS (Presentation TimeStamp) of the output audio frame,
4042 expressed in @var{TB} units.
4045 The PTS of the output audio frame, expressed in seconds.
4048 The timebase of the output audio frames.
4051 Default is @code{1024}.
4054 @subsection Examples
4059 Generate a simple 440 Hz sine wave:
4065 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
4069 sine=frequency=220:beep_factor=4:duration=5
4073 Generate a 1 kHz sine wave following @code{1602,1601,1602,1601,1602} NTSC
4076 sine=1000:samples_per_frame='st(0,mod(n,5)); 1602-not(not(eq(ld(0),1)+eq(ld(0),3)))'
4080 @c man end AUDIO SOURCES
4082 @chapter Audio Sinks
4083 @c man begin AUDIO SINKS
4085 Below is a description of the currently available audio sinks.
4087 @section abuffersink
4089 Buffer audio frames, and make them available to the end of filter chain.
4091 This sink is mainly intended for programmatic use, in particular
4092 through the interface defined in @file{libavfilter/buffersink.h}
4093 or the options system.
4095 It accepts a pointer to an AVABufferSinkContext structure, which
4096 defines the incoming buffers' formats, to be passed as the opaque
4097 parameter to @code{avfilter_init_filter} for initialization.
4100 Null audio sink; do absolutely nothing with the input audio. It is
4101 mainly useful as a template and for use in analysis / debugging
4104 @c man end AUDIO SINKS
4106 @chapter Video Filters
4107 @c man begin VIDEO FILTERS
4109 When you configure your FFmpeg build, you can disable any of the
4110 existing filters using @code{--disable-filters}.
4111 The configure output will show the video filters included in your
4114 Below is a description of the currently available video filters.
4116 @section alphaextract
4118 Extract the alpha component from the input as a grayscale video. This
4119 is especially useful with the @var{alphamerge} filter.
4123 Add or replace the alpha component of the primary input with the
4124 grayscale value of a second input. This is intended for use with
4125 @var{alphaextract} to allow the transmission or storage of frame
4126 sequences that have alpha in a format that doesn't support an alpha
4129 For example, to reconstruct full frames from a normal YUV-encoded video
4130 and a separate video created with @var{alphaextract}, you might use:
4132 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
4135 Since this filter is designed for reconstruction, it operates on frame
4136 sequences without considering timestamps, and terminates when either
4137 input reaches end of stream. This will cause problems if your encoding
4138 pipeline drops frames. If you're trying to apply an image as an
4139 overlay to a video stream, consider the @var{overlay} filter instead.
4143 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
4144 and libavformat to work. On the other hand, it is limited to ASS (Advanced
4145 Substation Alpha) subtitles files.
4147 This filter accepts the following option in addition to the common options from
4148 the @ref{subtitles} filter:
4152 Set the shaping engine
4154 Available values are:
4157 The default libass shaping engine, which is the best available.
4159 Fast, font-agnostic shaper that can do only substitutions
4161 Slower shaper using OpenType for substitutions and positioning
4164 The default is @code{auto}.
4168 Apply an Adaptive Temporal Averaging Denoiser to the video input.
4170 The filter accepts the following options:
4174 Set threshold A for 1st plane. Default is 0.02.
4175 Valid range is 0 to 0.3.
4178 Set threshold B for 1st plane. Default is 0.04.
4179 Valid range is 0 to 5.
4182 Set threshold A for 2nd plane. Default is 0.02.
4183 Valid range is 0 to 0.3.
4186 Set threshold B for 2nd plane. Default is 0.04.
4187 Valid range is 0 to 5.
4190 Set threshold A for 3rd plane. Default is 0.02.
4191 Valid range is 0 to 0.3.
4194 Set threshold B for 3rd plane. Default is 0.04.
4195 Valid range is 0 to 5.
4197 Threshold A is designed to react on abrupt changes in the input signal and
4198 threshold B is designed to react on continuous changes in the input signal.
4201 Set number of frames filter will use for averaging. Default is 33. Must be odd
4202 number in range [5, 129].
4207 Compute the bounding box for the non-black pixels in the input frame
4210 This filter computes the bounding box containing all the pixels with a
4211 luminance value greater than the minimum allowed value.
4212 The parameters describing the bounding box are printed on the filter
4215 The filter accepts the following option:
4219 Set the minimal luminance value. Default is @code{16}.
4222 @section blackdetect
4224 Detect video intervals that are (almost) completely black. Can be
4225 useful to detect chapter transitions, commercials, or invalid
4226 recordings. Output lines contains the time for the start, end and
4227 duration of the detected black interval expressed in seconds.
4229 In order to display the output lines, you need to set the loglevel at
4230 least to the AV_LOG_INFO value.
4232 The filter accepts the following options:
4235 @item black_min_duration, d
4236 Set the minimum detected black duration expressed in seconds. It must
4237 be a non-negative floating point number.
4239 Default value is 2.0.
4241 @item picture_black_ratio_th, pic_th
4242 Set the threshold for considering a picture "black".
4243 Express the minimum value for the ratio:
4245 @var{nb_black_pixels} / @var{nb_pixels}
4248 for which a picture is considered black.
4249 Default value is 0.98.
4251 @item pixel_black_th, pix_th
4252 Set the threshold for considering a pixel "black".
4254 The threshold expresses the maximum pixel luminance value for which a
4255 pixel is considered "black". The provided value is scaled according to
4256 the following equation:
4258 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
4261 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
4262 the input video format, the range is [0-255] for YUV full-range
4263 formats and [16-235] for YUV non full-range formats.
4265 Default value is 0.10.
4268 The following example sets the maximum pixel threshold to the minimum
4269 value, and detects only black intervals of 2 or more seconds:
4271 blackdetect=d=2:pix_th=0.00
4276 Detect frames that are (almost) completely black. Can be useful to
4277 detect chapter transitions or commercials. Output lines consist of
4278 the frame number of the detected frame, the percentage of blackness,
4279 the position in the file if known or -1 and the timestamp in seconds.
4281 In order to display the output lines, you need to set the loglevel at
4282 least to the AV_LOG_INFO value.
4284 It accepts the following parameters:
4289 The percentage of the pixels that have to be below the threshold; it defaults to
4292 @item threshold, thresh
4293 The threshold below which a pixel value is considered black; it defaults to
4298 @section blend, tblend
4300 Blend two video frames into each other.
4302 The @code{blend} filter takes two input streams and outputs one
4303 stream, the first input is the "top" layer and second input is
4304 "bottom" layer. Output terminates when shortest input terminates.
4306 The @code{tblend} (time blend) filter takes two consecutive frames
4307 from one single stream, and outputs the result obtained by blending
4308 the new frame on top of the old frame.
4310 A description of the accepted options follows.
4318 Set blend mode for specific pixel component or all pixel components in case
4319 of @var{all_mode}. Default value is @code{normal}.
4321 Available values for component modes are:
4362 Set blend opacity for specific pixel component or all pixel components in case
4363 of @var{all_opacity}. Only used in combination with pixel component blend modes.
4370 Set blend expression for specific pixel component or all pixel components in case
4371 of @var{all_expr}. Note that related mode options will be ignored if those are set.
4373 The expressions can use the following variables:
4377 The sequential number of the filtered frame, starting from @code{0}.
4381 the coordinates of the current sample
4385 the width and height of currently filtered plane
4389 Width and height scale depending on the currently filtered plane. It is the
4390 ratio between the corresponding luma plane number of pixels and the current
4391 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4392 @code{0.5,0.5} for chroma planes.
4395 Time of the current frame, expressed in seconds.
4398 Value of pixel component at current location for first video frame (top layer).
4401 Value of pixel component at current location for second video frame (bottom layer).
4405 Force termination when the shortest input terminates. Default is
4406 @code{0}. This option is only defined for the @code{blend} filter.
4409 Continue applying the last bottom frame after the end of the stream. A value of
4410 @code{0} disable the filter after the last frame of the bottom layer is reached.
4411 Default is @code{1}. This option is only defined for the @code{blend} filter.
4414 @subsection Examples
4418 Apply transition from bottom layer to top layer in first 10 seconds:
4420 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
4424 Apply 1x1 checkerboard effect:
4426 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
4430 Apply uncover left effect:
4432 blend=all_expr='if(gte(N*SW+X,W),A,B)'
4436 Apply uncover down effect:
4438 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
4442 Apply uncover up-left effect:
4444 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
4448 Split diagonally video and shows top and bottom layer on each side:
4450 blend=all_expr=if(gt(X,Y*(W/H)),A,B)
4454 Display differences between the current and the previous frame:
4456 tblend=all_mode=difference128
4462 Deinterlace the input video ("bwdif" stands for "Bob Weaver
4463 Deinterlacing Filter").
4465 Motion adaptive deinterlacing based on yadif with the use of w3fdif and cubic
4466 interpolation algorithms.
4467 It accepts the following parameters:
4471 The interlacing mode to adopt. It accepts one of the following values:
4475 Output one frame for each frame.
4477 Output one frame for each field.
4480 The default value is @code{send_field}.
4483 The picture field parity assumed for the input interlaced video. It accepts one
4484 of the following values:
4488 Assume the top field is first.
4490 Assume the bottom field is first.
4492 Enable automatic detection of field parity.
4495 The default value is @code{auto}.
4496 If the interlacing is unknown or the decoder does not export this information,
4497 top field first will be assumed.
4500 Specify which frames to deinterlace. Accept one of the following
4505 Deinterlace all frames.
4507 Only deinterlace frames marked as interlaced.
4510 The default value is @code{all}.
4515 Apply a boxblur algorithm to the input video.
4517 It accepts the following parameters:
4521 @item luma_radius, lr
4522 @item luma_power, lp
4523 @item chroma_radius, cr
4524 @item chroma_power, cp
4525 @item alpha_radius, ar
4526 @item alpha_power, ap
4530 A description of the accepted options follows.
4533 @item luma_radius, lr
4534 @item chroma_radius, cr
4535 @item alpha_radius, ar
4536 Set an expression for the box radius in pixels used for blurring the
4537 corresponding input plane.
4539 The radius value must be a non-negative number, and must not be
4540 greater than the value of the expression @code{min(w,h)/2} for the
4541 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
4544 Default value for @option{luma_radius} is "2". If not specified,
4545 @option{chroma_radius} and @option{alpha_radius} default to the
4546 corresponding value set for @option{luma_radius}.
4548 The expressions can contain the following constants:
4552 The input width and height in pixels.
4556 The input chroma image width and height in pixels.
4560 The horizontal and vertical chroma subsample values. For example, for the
4561 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
4564 @item luma_power, lp
4565 @item chroma_power, cp
4566 @item alpha_power, ap
4567 Specify how many times the boxblur filter is applied to the
4568 corresponding plane.
4570 Default value for @option{luma_power} is 2. If not specified,
4571 @option{chroma_power} and @option{alpha_power} default to the
4572 corresponding value set for @option{luma_power}.
4574 A value of 0 will disable the effect.
4577 @subsection Examples
4581 Apply a boxblur filter with the luma, chroma, and alpha radii
4584 boxblur=luma_radius=2:luma_power=1
4589 Set the luma radius to 2, and alpha and chroma radius to 0:
4591 boxblur=2:1:cr=0:ar=0
4595 Set the luma and chroma radii to a fraction of the video dimension:
4597 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
4602 YUV colorspace color/chroma keying.
4604 The filter accepts the following options:
4608 The color which will be replaced with transparency.
4611 Similarity percentage with the key color.
4613 0.01 matches only the exact key color, while 1.0 matches everything.
4618 0.0 makes pixels either fully transparent, or not transparent at all.
4620 Higher values result in semi-transparent pixels, with a higher transparency
4621 the more similar the pixels color is to the key color.
4624 Signals that the color passed is already in YUV instead of RGB.
4626 Litteral colors like "green" or "red" don't make sense with this enabled anymore.
4627 This can be used to pass exact YUV values as hexadecimal numbers.
4630 @subsection Examples
4634 Make every green pixel in the input image transparent:
4636 ffmpeg -i input.png -vf chromakey=green out.png
4640 Overlay a greenscreen-video on top of a static black background.
4642 ffmpeg -f lavfi -i color=c=black:s=1280x720 -i video.mp4 -shortest -filter_complex "[1:v]chromakey=0x70de77:0.1:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.mkv
4648 Display CIE color diagram with pixels overlaid onto it.
4650 The filter acccepts the following options:
4665 @item uhdtv, rec2020
4678 Set what gamuts to draw.
4680 See @code{system} option for avaiable values.
4683 Set ciescope size, by default set to 512.
4686 Set intensity used to map input pixel values to CIE diagram.
4689 Set contrast used to draw tongue colors that are out of active color system gamut.
4692 Correct gamma displayed on scope, by default enabled.
4695 Show white point on CIE diagram, by default disabled.
4698 Set input gamma. Used only with XYZ input color space.
4703 Visualize information exported by some codecs.
4705 Some codecs can export information through frames using side-data or other
4706 means. For example, some MPEG based codecs export motion vectors through the
4707 @var{export_mvs} flag in the codec @option{flags2} option.
4709 The filter accepts the following option:
4713 Set motion vectors to visualize.
4715 Available flags for @var{mv} are:
4719 forward predicted MVs of P-frames
4721 forward predicted MVs of B-frames
4723 backward predicted MVs of B-frames
4727 Display quantization parameters using the chroma planes
4730 @subsection Examples
4734 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
4736 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
4740 @section colorbalance
4741 Modify intensity of primary colors (red, green and blue) of input frames.
4743 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
4744 regions for the red-cyan, green-magenta or blue-yellow balance.
4746 A positive adjustment value shifts the balance towards the primary color, a negative
4747 value towards the complementary color.
4749 The filter accepts the following options:
4755 Adjust red, green and blue shadows (darkest pixels).
4760 Adjust red, green and blue midtones (medium pixels).
4765 Adjust red, green and blue highlights (brightest pixels).
4767 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
4770 @subsection Examples
4774 Add red color cast to shadows:
4781 RGB colorspace color keying.
4783 The filter accepts the following options:
4787 The color which will be replaced with transparency.
4790 Similarity percentage with the key color.
4792 0.01 matches only the exact key color, while 1.0 matches everything.
4797 0.0 makes pixels either fully transparent, or not transparent at all.
4799 Higher values result in semi-transparent pixels, with a higher transparency
4800 the more similar the pixels color is to the key color.
4803 @subsection Examples
4807 Make every green pixel in the input image transparent:
4809 ffmpeg -i input.png -vf colorkey=green out.png
4813 Overlay a greenscreen-video on top of a static background image.
4815 ffmpeg -i background.png -i video.mp4 -filter_complex "[1:v]colorkey=0x3BBD1E:0.3:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.flv
4819 @section colorlevels
4821 Adjust video input frames using levels.
4823 The filter accepts the following options:
4830 Adjust red, green, blue and alpha input black point.
4831 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
4837 Adjust red, green, blue and alpha input white point.
4838 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
4840 Input levels are used to lighten highlights (bright tones), darken shadows
4841 (dark tones), change the balance of bright and dark tones.
4847 Adjust red, green, blue and alpha output black point.
4848 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
4854 Adjust red, green, blue and alpha output white point.
4855 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
4857 Output levels allows manual selection of a constrained output level range.
4860 @subsection Examples
4864 Make video output darker:
4866 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
4872 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
4876 Make video output lighter:
4878 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
4882 Increase brightness:
4884 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
4888 @section colorchannelmixer
4890 Adjust video input frames by re-mixing color channels.
4892 This filter modifies a color channel by adding the values associated to
4893 the other channels of the same pixels. For example if the value to
4894 modify is red, the output value will be:
4896 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
4899 The filter accepts the following options:
4906 Adjust contribution of input red, green, blue and alpha channels for output red channel.
4907 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
4913 Adjust contribution of input red, green, blue and alpha channels for output green channel.
4914 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
4920 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
4921 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
4927 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
4928 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
4930 Allowed ranges for options are @code{[-2.0, 2.0]}.
4933 @subsection Examples
4937 Convert source to grayscale:
4939 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
4942 Simulate sepia tones:
4944 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
4948 @section colormatrix
4950 Convert color matrix.
4952 The filter accepts the following options:
4957 Specify the source and destination color matrix. Both values must be
4960 The accepted values are:
4976 For example to convert from BT.601 to SMPTE-240M, use the command:
4978 colormatrix=bt601:smpte240m
4983 Convert colorspace, transfer characteristics or color primaries.
4985 The filter accepts the following options:
4989 Specify all color properties at once.
4991 The accepted values are:
5020 Specify output colorspace.
5022 The accepted values are:
5031 BT.470BG or BT.601-6 625
5034 SMPTE-170M or BT.601-6 525
5040 BT.2020 with non-constant luminance
5045 Specify output transfer characteristics.
5047 The accepted values are:
5053 Constant gamma of 2.2
5056 Constant gamma of 2.8
5059 SMPTE-170M, BT.601-6 625 or BT.601-6 525
5065 BT.2020 for 10-bits content
5068 BT.2020 for 12-bits content
5073 Specify output color primaries.
5075 The accepted values are:
5084 BT.470BG or BT.601-6 625
5087 SMPTE-170M or BT.601-6 525
5098 Specify output color range.
5100 The accepted values are:
5103 MPEG (restricted) range
5111 Specify output color format.
5113 The accepted values are:
5116 YUV 4:2:0 planar 8-bits
5119 YUV 4:2:0 planar 10-bits
5122 YUV 4:2:0 planar 12-bits
5125 YUV 4:2:2 planar 8-bits
5128 YUV 4:2:2 planar 10-bits
5131 YUV 4:2:2 planar 12-bits
5134 YUV 4:4:4 planar 8-bits
5137 YUV 4:4:4 planar 10-bits
5140 YUV 4:4:4 planar 12-bits
5145 Do a fast conversion, which skips gamma/primary correction. This will take
5146 significantly less CPU, but will be mathematically incorrect. To get output
5147 compatible with that produced by the colormatrix filter, use fast=1.
5150 The filter converts the transfer characteristics, color space and color
5151 primaries to the specified user values. The output value, if not specified,
5152 is set to a default value based on the "all" property. If that property is
5153 also not specified, the filter will log an error. The output color range and
5154 format default to the same value as the input color range and format. The
5155 input transfer characteristics, color space, color primaries and color range
5156 should be set on the input data. If any of these are missing, the filter will
5157 log an error and no conversion will take place.
5159 For example to convert the input to SMPTE-240M, use the command:
5161 colorspace=smpte240m
5164 @section convolution
5166 Apply convolution 3x3 or 5x5 filter.
5168 The filter accepts the following options:
5175 Set matrix for each plane.
5176 Matrix is sequence of 9 or 25 signed integers.
5182 Set multiplier for calculated value for each plane.
5188 Set bias for each plane. This value is added to the result of the multiplication.
5189 Useful for making the overall image brighter or darker. Default is 0.0.
5192 @subsection Examples
5198 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"
5204 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"
5210 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"
5216 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"
5222 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"
5228 Copy the input source unchanged to the output. This is mainly useful for
5233 Video filtering on GPU using Apple's CoreImage API on OSX.
5235 Hardware acceleration is based on an OpenGL context. Usually, this means it is
5236 processed by video hardware. However, software-based OpenGL implementations
5237 exist which means there is no guarantee for hardware processing. It depends on
5240 There are many filters and image generators provided by Apple that come with a
5241 large variety of options. The filter has to be referenced by its name along
5244 The coreimage filter accepts the following options:
5247 List all available filters and generators along with all their respective
5248 options as well as possible minimum and maximum values along with the default
5255 Specify all filters by their respective name and options.
5256 Use @var{list_filters} to determine all valid filter names and options.
5257 Numerical options are specified by a float value and are automatically clamped
5258 to their respective value range. Vector and color options have to be specified
5259 by a list of space separated float values. Character escaping has to be done.
5260 A special option name @code{default} is available to use default options for a
5263 It is required to specify either @code{default} or at least one of the filter options.
5264 All omitted options are used with their default values.
5265 The syntax of the filter string is as follows:
5267 filter=<NAME>@@<OPTION>=<VALUE>[@@<OPTION>=<VALUE>][@@...][#<NAME>@@<OPTION>=<VALUE>[@@<OPTION>=<VALUE>][@@...]][#...]
5271 Specify a rectangle where the output of the filter chain is copied into the
5272 input image. It is given by a list of space separated float values:
5274 output_rect=x\ y\ width\ height
5276 If not given, the output rectangle equals the dimensions of the input image.
5277 The output rectangle is automatically cropped at the borders of the input
5278 image. Negative values are valid for each component.
5280 output_rect=25\ 25\ 100\ 100
5284 Several filters can be chained for successive processing without GPU-HOST
5285 transfers allowing for fast processing of complex filter chains.
5286 Currently, only filters with zero (generators) or exactly one (filters) input
5287 image and one output image are supported. Also, transition filters are not yet
5290 Some filters generate output images with additional padding depending on the
5291 respective filter kernel. The padding is automatically removed to ensure the
5292 filter output has the same size as the input image.
5294 For image generators, the size of the output image is determined by the
5295 previous output image of the filter chain or the input image of the whole
5296 filterchain, respectively. The generators do not use the pixel information of
5297 this image to generate their output. However, the generated output is
5298 blended onto this image, resulting in partial or complete coverage of the
5301 The @ref{coreimagesrc} video source can be used for generating input images
5302 which are directly fed into the filter chain. By using it, providing input
5303 images by another video source or an input video is not required.
5305 @subsection Examples
5310 List all filters available:
5312 coreimage=list_filters=true
5316 Use the CIBoxBlur filter with default options to blur an image:
5318 coreimage=filter=CIBoxBlur@@default
5322 Use a filter chain with CISepiaTone at default values and CIVignetteEffect with
5323 its center at 100x100 and a radius of 50 pixels:
5325 coreimage=filter=CIBoxBlur@@default#CIVignetteEffect@@inputCenter=100\ 100@@inputRadius=50
5329 Use nullsrc and CIQRCodeGenerator to create a QR code for the FFmpeg homepage,
5330 given as complete and escaped command-line for Apple's standard bash shell:
5332 ffmpeg -f lavfi -i nullsrc=s=100x100,coreimage=filter=CIQRCodeGenerator@@inputMessage=https\\\\\://FFmpeg.org/@@inputCorrectionLevel=H -frames:v 1 QRCode.png
5338 Crop the input video to given dimensions.
5340 It accepts the following parameters:
5344 The width of the output video. It defaults to @code{iw}.
5345 This expression is evaluated only once during the filter
5346 configuration, or when the @samp{w} or @samp{out_w} command is sent.
5349 The height of the output video. It defaults to @code{ih}.
5350 This expression is evaluated only once during the filter
5351 configuration, or when the @samp{h} or @samp{out_h} command is sent.
5354 The horizontal position, in the input video, of the left edge of the output
5355 video. It defaults to @code{(in_w-out_w)/2}.
5356 This expression is evaluated per-frame.
5359 The vertical position, in the input video, of the top edge of the output video.
5360 It defaults to @code{(in_h-out_h)/2}.
5361 This expression is evaluated per-frame.
5364 If set to 1 will force the output display aspect ratio
5365 to be the same of the input, by changing the output sample aspect
5366 ratio. It defaults to 0.
5369 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
5370 expressions containing the following constants:
5375 The computed values for @var{x} and @var{y}. They are evaluated for
5380 The input width and height.
5384 These are the same as @var{in_w} and @var{in_h}.
5388 The output (cropped) width and height.
5392 These are the same as @var{out_w} and @var{out_h}.
5395 same as @var{iw} / @var{ih}
5398 input sample aspect ratio
5401 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
5405 horizontal and vertical chroma subsample values. For example for the
5406 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5409 The number of the input frame, starting from 0.
5412 the position in the file of the input frame, NAN if unknown
5415 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
5419 The expression for @var{out_w} may depend on the value of @var{out_h},
5420 and the expression for @var{out_h} may depend on @var{out_w}, but they
5421 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
5422 evaluated after @var{out_w} and @var{out_h}.
5424 The @var{x} and @var{y} parameters specify the expressions for the
5425 position of the top-left corner of the output (non-cropped) area. They
5426 are evaluated for each frame. If the evaluated value is not valid, it
5427 is approximated to the nearest valid value.
5429 The expression for @var{x} may depend on @var{y}, and the expression
5430 for @var{y} may depend on @var{x}.
5432 @subsection Examples
5436 Crop area with size 100x100 at position (12,34).
5441 Using named options, the example above becomes:
5443 crop=w=100:h=100:x=12:y=34
5447 Crop the central input area with size 100x100:
5453 Crop the central input area with size 2/3 of the input video:
5455 crop=2/3*in_w:2/3*in_h
5459 Crop the input video central square:
5466 Delimit the rectangle with the top-left corner placed at position
5467 100:100 and the right-bottom corner corresponding to the right-bottom
5468 corner of the input image.
5470 crop=in_w-100:in_h-100:100:100
5474 Crop 10 pixels from the left and right borders, and 20 pixels from
5475 the top and bottom borders
5477 crop=in_w-2*10:in_h-2*20
5481 Keep only the bottom right quarter of the input image:
5483 crop=in_w/2:in_h/2:in_w/2:in_h/2
5487 Crop height for getting Greek harmony:
5489 crop=in_w:1/PHI*in_w
5493 Apply trembling effect:
5495 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)
5499 Apply erratic camera effect depending on timestamp:
5501 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)"
5505 Set x depending on the value of y:
5507 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
5511 @subsection Commands
5513 This filter supports the following commands:
5519 Set width/height of the output video and the horizontal/vertical position
5521 The command accepts the same syntax of the corresponding option.
5523 If the specified expression is not valid, it is kept at its current
5529 Auto-detect the crop size.
5531 It calculates the necessary cropping parameters and prints the
5532 recommended parameters via the logging system. The detected dimensions
5533 correspond to the non-black area of the input video.
5535 It accepts the following parameters:
5540 Set higher black value threshold, which can be optionally specified
5541 from nothing (0) to everything (255 for 8bit based formats). An intensity
5542 value greater to the set value is considered non-black. It defaults to 24.
5543 You can also specify a value between 0.0 and 1.0 which will be scaled depending
5544 on the bitdepth of the pixel format.
5547 The value which the width/height should be divisible by. It defaults to
5548 16. The offset is automatically adjusted to center the video. Use 2 to
5549 get only even dimensions (needed for 4:2:2 video). 16 is best when
5550 encoding to most video codecs.
5552 @item reset_count, reset
5553 Set the counter that determines after how many frames cropdetect will
5554 reset the previously detected largest video area and start over to
5555 detect the current optimal crop area. Default value is 0.
5557 This can be useful when channel logos distort the video area. 0
5558 indicates 'never reset', and returns the largest area encountered during
5565 Apply color adjustments using curves.
5567 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
5568 component (red, green and blue) has its values defined by @var{N} key points
5569 tied from each other using a smooth curve. The x-axis represents the pixel
5570 values from the input frame, and the y-axis the new pixel values to be set for
5573 By default, a component curve is defined by the two points @var{(0;0)} and
5574 @var{(1;1)}. This creates a straight line where each original pixel value is
5575 "adjusted" to its own value, which means no change to the image.
5577 The filter allows you to redefine these two points and add some more. A new
5578 curve (using a natural cubic spline interpolation) will be define to pass
5579 smoothly through all these new coordinates. The new defined points needs to be
5580 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
5581 be in the @var{[0;1]} interval. If the computed curves happened to go outside
5582 the vector spaces, the values will be clipped accordingly.
5584 If there is no key point defined in @code{x=0}, the filter will automatically
5585 insert a @var{(0;0)} point. In the same way, if there is no key point defined
5586 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
5588 The filter accepts the following options:
5592 Select one of the available color presets. This option can be used in addition
5593 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
5594 options takes priority on the preset values.
5595 Available presets are:
5598 @item color_negative
5601 @item increase_contrast
5603 @item linear_contrast
5604 @item medium_contrast
5606 @item strong_contrast
5609 Default is @code{none}.
5611 Set the master key points. These points will define a second pass mapping. It
5612 is sometimes called a "luminance" or "value" mapping. It can be used with
5613 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
5614 post-processing LUT.
5616 Set the key points for the red component.
5618 Set the key points for the green component.
5620 Set the key points for the blue component.
5622 Set the key points for all components (not including master).
5623 Can be used in addition to the other key points component
5624 options. In this case, the unset component(s) will fallback on this
5625 @option{all} setting.
5627 Specify a Photoshop curves file (@code{.acv}) to import the settings from.
5630 To avoid some filtergraph syntax conflicts, each key points list need to be
5631 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
5633 @subsection Examples
5637 Increase slightly the middle level of blue:
5639 curves=blue='0.5/0.58'
5645 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
5647 Here we obtain the following coordinates for each components:
5650 @code{(0;0.11) (0.42;0.51) (1;0.95)}
5652 @code{(0;0) (0.50;0.48) (1;1)}
5654 @code{(0;0.22) (0.49;0.44) (1;0.80)}
5658 The previous example can also be achieved with the associated built-in preset:
5660 curves=preset=vintage
5670 Use a Photoshop preset and redefine the points of the green component:
5672 curves=psfile='MyCurvesPresets/purple.acv':green='0.45/0.53'
5678 Video data analysis filter.
5680 This filter shows hexadecimal pixel values of part of video.
5682 The filter accepts the following options:
5686 Set output video size.
5689 Set x offset from where to pick pixels.
5692 Set y offset from where to pick pixels.
5695 Set scope mode, can be one of the following:
5698 Draw hexadecimal pixel values with white color on black background.
5701 Draw hexadecimal pixel values with input video pixel color on black
5705 Draw hexadecimal pixel values on color background picked from input video,
5706 the text color is picked in such way so its always visible.
5710 Draw rows and columns numbers on left and top of video.
5715 Denoise frames using 2D DCT (frequency domain filtering).
5717 This filter is not designed for real time.
5719 The filter accepts the following options:
5723 Set the noise sigma constant.
5725 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
5726 coefficient (absolute value) below this threshold with be dropped.
5728 If you need a more advanced filtering, see @option{expr}.
5730 Default is @code{0}.
5733 Set number overlapping pixels for each block. Since the filter can be slow, you
5734 may want to reduce this value, at the cost of a less effective filter and the
5735 risk of various artefacts.
5737 If the overlapping value doesn't permit processing the whole input width or
5738 height, a warning will be displayed and according borders won't be denoised.
5740 Default value is @var{blocksize}-1, which is the best possible setting.
5743 Set the coefficient factor expression.
5745 For each coefficient of a DCT block, this expression will be evaluated as a
5746 multiplier value for the coefficient.
5748 If this is option is set, the @option{sigma} option will be ignored.
5750 The absolute value of the coefficient can be accessed through the @var{c}
5754 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
5755 @var{blocksize}, which is the width and height of the processed blocks.
5757 The default value is @var{3} (8x8) and can be raised to @var{4} for a
5758 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
5759 on the speed processing. Also, a larger block size does not necessarily means a
5763 @subsection Examples
5765 Apply a denoise with a @option{sigma} of @code{4.5}:
5770 The same operation can be achieved using the expression system:
5772 dctdnoiz=e='gte(c, 4.5*3)'
5775 Violent denoise using a block size of @code{16x16}:
5782 Remove banding artifacts from input video.
5783 It works by replacing banded pixels with average value of referenced pixels.
5785 The filter accepts the following options:
5792 Set banding detection threshold for each plane. Default is 0.02.
5793 Valid range is 0.00003 to 0.5.
5794 If difference between current pixel and reference pixel is less than threshold,
5795 it will be considered as banded.
5798 Banding detection range in pixels. Default is 16. If positive, random number
5799 in range 0 to set value will be used. If negative, exact absolute value
5801 The range defines square of four pixels around current pixel.
5804 Set direction in radians from which four pixel will be compared. If positive,
5805 random direction from 0 to set direction will be picked. If negative, exact of
5806 absolute value will be picked. For example direction 0, -PI or -2*PI radians
5807 will pick only pixels on same row and -PI/2 will pick only pixels on same
5811 If enabled, current pixel is compared with average value of all four
5812 surrounding pixels. The default is enabled. If disabled current pixel is
5813 compared with all four surrounding pixels. The pixel is considered banded
5814 if only all four differences with surrounding pixels are less than threshold.
5820 Drop duplicated frames at regular intervals.
5822 The filter accepts the following options:
5826 Set the number of frames from which one will be dropped. Setting this to
5827 @var{N} means one frame in every batch of @var{N} frames will be dropped.
5828 Default is @code{5}.
5831 Set the threshold for duplicate detection. If the difference metric for a frame
5832 is less than or equal to this value, then it is declared as duplicate. Default
5836 Set scene change threshold. Default is @code{15}.
5840 Set the size of the x and y-axis blocks used during metric calculations.
5841 Larger blocks give better noise suppression, but also give worse detection of
5842 small movements. Must be a power of two. Default is @code{32}.
5845 Mark main input as a pre-processed input and activate clean source input
5846 stream. This allows the input to be pre-processed with various filters to help
5847 the metrics calculation while keeping the frame selection lossless. When set to
5848 @code{1}, the first stream is for the pre-processed input, and the second
5849 stream is the clean source from where the kept frames are chosen. Default is
5853 Set whether or not chroma is considered in the metric calculations. Default is
5859 Apply deflate effect to the video.
5861 This filter replaces the pixel by the local(3x3) average by taking into account
5862 only values lower than the pixel.
5864 It accepts the following options:
5871 Limit the maximum change for each plane, default is 65535.
5872 If 0, plane will remain unchanged.
5877 Remove judder produced by partially interlaced telecined content.
5879 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
5880 source was partially telecined content then the output of @code{pullup,dejudder}
5881 will have a variable frame rate. May change the recorded frame rate of the
5882 container. Aside from that change, this filter will not affect constant frame
5885 The option available in this filter is:
5889 Specify the length of the window over which the judder repeats.
5891 Accepts any integer greater than 1. Useful values are:
5895 If the original was telecined from 24 to 30 fps (Film to NTSC).
5898 If the original was telecined from 25 to 30 fps (PAL to NTSC).
5901 If a mixture of the two.
5904 The default is @samp{4}.
5909 Suppress a TV station logo by a simple interpolation of the surrounding
5910 pixels. Just set a rectangle covering the logo and watch it disappear
5911 (and sometimes something even uglier appear - your mileage may vary).
5913 It accepts the following parameters:
5918 Specify the top left corner coordinates of the logo. They must be
5923 Specify the width and height of the logo to clear. They must be
5927 Specify the thickness of the fuzzy edge of the rectangle (added to
5928 @var{w} and @var{h}). The default value is 1. This option is
5929 deprecated, setting higher values should no longer be necessary and
5933 When set to 1, a green rectangle is drawn on the screen to simplify
5934 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
5935 The default value is 0.
5937 The rectangle is drawn on the outermost pixels which will be (partly)
5938 replaced with interpolated values. The values of the next pixels
5939 immediately outside this rectangle in each direction will be used to
5940 compute the interpolated pixel values inside the rectangle.
5944 @subsection Examples
5948 Set a rectangle covering the area with top left corner coordinates 0,0
5949 and size 100x77, and a band of size 10:
5951 delogo=x=0:y=0:w=100:h=77:band=10
5958 Attempt to fix small changes in horizontal and/or vertical shift. This
5959 filter helps remove camera shake from hand-holding a camera, bumping a
5960 tripod, moving on a vehicle, etc.
5962 The filter accepts the following options:
5970 Specify a rectangular area where to limit the search for motion
5972 If desired the search for motion vectors can be limited to a
5973 rectangular area of the frame defined by its top left corner, width
5974 and height. These parameters have the same meaning as the drawbox
5975 filter which can be used to visualise the position of the bounding
5978 This is useful when simultaneous movement of subjects within the frame
5979 might be confused for camera motion by the motion vector search.
5981 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
5982 then the full frame is used. This allows later options to be set
5983 without specifying the bounding box for the motion vector search.
5985 Default - search the whole frame.
5989 Specify the maximum extent of movement in x and y directions in the
5990 range 0-64 pixels. Default 16.
5993 Specify how to generate pixels to fill blanks at the edge of the
5994 frame. Available values are:
5997 Fill zeroes at blank locations
5999 Original image at blank locations
6001 Extruded edge value at blank locations
6003 Mirrored edge at blank locations
6005 Default value is @samp{mirror}.
6008 Specify the blocksize to use for motion search. Range 4-128 pixels,
6012 Specify the contrast threshold for blocks. Only blocks with more than
6013 the specified contrast (difference between darkest and lightest
6014 pixels) will be considered. Range 1-255, default 125.
6017 Specify the search strategy. Available values are:
6020 Set exhaustive search
6022 Set less exhaustive search.
6024 Default value is @samp{exhaustive}.
6027 If set then a detailed log of the motion search is written to the
6031 If set to 1, specify using OpenCL capabilities, only available if
6032 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
6038 Apply an exact inverse of the telecine operation. It requires a predefined
6039 pattern specified using the pattern option which must be the same as that passed
6040 to the telecine filter.
6042 This filter accepts the following options:
6051 The default value is @code{top}.
6055 A string of numbers representing the pulldown pattern you wish to apply.
6056 The default value is @code{23}.
6059 A number representing position of the first frame with respect to the telecine
6060 pattern. This is to be used if the stream is cut. The default value is @code{0}.
6065 Apply dilation effect to the video.
6067 This filter replaces the pixel by the local(3x3) maximum.
6069 It accepts the following options:
6076 Limit the maximum change for each plane, default is 65535.
6077 If 0, plane will remain unchanged.
6080 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
6083 Flags to local 3x3 coordinates maps like this:
6092 Displace pixels as indicated by second and third input stream.
6094 It takes three input streams and outputs one stream, the first input is the
6095 source, and second and third input are displacement maps.
6097 The second input specifies how much to displace pixels along the
6098 x-axis, while the third input specifies how much to displace pixels
6100 If one of displacement map streams terminates, last frame from that
6101 displacement map will be used.
6103 Note that once generated, displacements maps can be reused over and over again.
6105 A description of the accepted options follows.
6109 Set displace behavior for pixels that are out of range.
6111 Available values are:
6114 Missing pixels are replaced by black pixels.
6117 Adjacent pixels will spread out to replace missing pixels.
6120 Out of range pixels are wrapped so they point to pixels of other side.
6122 Default is @samp{smear}.
6126 @subsection Examples
6130 Add ripple effect to rgb input of video size hd720:
6132 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
6136 Add wave effect to rgb input of video size hd720:
6138 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
6144 Draw a colored box on the input image.
6146 It accepts the following parameters:
6151 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
6155 The expressions which specify the width and height of the box; if 0 they are interpreted as
6156 the input width and height. It defaults to 0.
6159 Specify the color of the box to write. For the general syntax of this option,
6160 check the "Color" section in the ffmpeg-utils manual. If the special
6161 value @code{invert} is used, the box edge color is the same as the
6162 video with inverted luma.
6165 The expression which sets the thickness of the box edge. Default value is @code{3}.
6167 See below for the list of accepted constants.
6170 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
6171 following constants:
6175 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
6179 horizontal and vertical chroma subsample values. For example for the
6180 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6184 The input width and height.
6187 The input sample aspect ratio.
6191 The x and y offset coordinates where the box is drawn.
6195 The width and height of the drawn box.
6198 The thickness of the drawn box.
6200 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
6201 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
6205 @subsection Examples
6209 Draw a black box around the edge of the input image:
6215 Draw a box with color red and an opacity of 50%:
6217 drawbox=10:20:200:60:red@@0.5
6220 The previous example can be specified as:
6222 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
6226 Fill the box with pink color:
6228 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
6232 Draw a 2-pixel red 2.40:1 mask:
6234 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
6238 @section drawgraph, adrawgraph
6240 Draw a graph using input video or audio metadata.
6242 It accepts the following parameters:
6246 Set 1st frame metadata key from which metadata values will be used to draw a graph.
6249 Set 1st foreground color expression.
6252 Set 2nd frame metadata key from which metadata values will be used to draw a graph.
6255 Set 2nd foreground color expression.
6258 Set 3rd frame metadata key from which metadata values will be used to draw a graph.
6261 Set 3rd foreground color expression.
6264 Set 4th frame metadata key from which metadata values will be used to draw a graph.
6267 Set 4th foreground color expression.
6270 Set minimal value of metadata value.
6273 Set maximal value of metadata value.
6276 Set graph background color. Default is white.
6281 Available values for mode is:
6288 Default is @code{line}.
6293 Available values for slide is:
6296 Draw new frame when right border is reached.
6299 Replace old columns with new ones.
6302 Scroll from right to left.
6305 Scroll from left to right.
6308 Default is @code{frame}.
6311 Set size of graph video. For the syntax of this option, check the
6312 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
6313 The default value is @code{900x256}.
6315 The foreground color expressions can use the following variables:
6318 Minimal value of metadata value.
6321 Maximal value of metadata value.
6324 Current metadata key value.
6327 The color is defined as 0xAABBGGRR.
6330 Example using metadata from @ref{signalstats} filter:
6332 signalstats,drawgraph=lavfi.signalstats.YAVG:min=0:max=255
6335 Example using metadata from @ref{ebur128} filter:
6337 ebur128=metadata=1,adrawgraph=lavfi.r128.M:min=-120:max=5
6342 Draw a grid on the input image.
6344 It accepts the following parameters:
6349 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
6353 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
6354 input width and height, respectively, minus @code{thickness}, so image gets
6355 framed. Default to 0.
6358 Specify the color of the grid. For the general syntax of this option,
6359 check the "Color" section in the ffmpeg-utils manual. If the special
6360 value @code{invert} is used, the grid color is the same as the
6361 video with inverted luma.
6364 The expression which sets the thickness of the grid line. Default value is @code{1}.
6366 See below for the list of accepted constants.
6369 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
6370 following constants:
6374 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
6378 horizontal and vertical chroma subsample values. For example for the
6379 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6383 The input grid cell width and height.
6386 The input sample aspect ratio.
6390 The x and y coordinates of some point of grid intersection (meant to configure offset).
6394 The width and height of the drawn cell.
6397 The thickness of the drawn cell.
6399 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
6400 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
6404 @subsection Examples
6408 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
6410 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
6414 Draw a white 3x3 grid with an opacity of 50%:
6416 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
6423 Draw a text string or text from a specified file on top of a video, using the
6424 libfreetype library.
6426 To enable compilation of this filter, you need to configure FFmpeg with
6427 @code{--enable-libfreetype}.
6428 To enable default font fallback and the @var{font} option you need to
6429 configure FFmpeg with @code{--enable-libfontconfig}.
6430 To enable the @var{text_shaping} option, you need to configure FFmpeg with
6431 @code{--enable-libfribidi}.
6435 It accepts the following parameters:
6440 Used to draw a box around text using the background color.
6441 The value must be either 1 (enable) or 0 (disable).
6442 The default value of @var{box} is 0.
6445 Set the width of the border to be drawn around the box using @var{boxcolor}.
6446 The default value of @var{boxborderw} is 0.
6449 The color to be used for drawing box around text. For the syntax of this
6450 option, check the "Color" section in the ffmpeg-utils manual.
6452 The default value of @var{boxcolor} is "white".
6455 Set the width of the border to be drawn around the text using @var{bordercolor}.
6456 The default value of @var{borderw} is 0.
6459 Set the color to be used for drawing border around text. For the syntax of this
6460 option, check the "Color" section in the ffmpeg-utils manual.
6462 The default value of @var{bordercolor} is "black".
6465 Select how the @var{text} is expanded. Can be either @code{none},
6466 @code{strftime} (deprecated) or
6467 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
6471 If true, check and fix text coords to avoid clipping.
6474 The color to be used for drawing fonts. For the syntax of this option, check
6475 the "Color" section in the ffmpeg-utils manual.
6477 The default value of @var{fontcolor} is "black".
6479 @item fontcolor_expr
6480 String which is expanded the same way as @var{text} to obtain dynamic
6481 @var{fontcolor} value. By default this option has empty value and is not
6482 processed. When this option is set, it overrides @var{fontcolor} option.
6485 The font family to be used for drawing text. By default Sans.
6488 The font file to be used for drawing text. The path must be included.
6489 This parameter is mandatory if the fontconfig support is disabled.
6492 This option does not exist, please see the timeline system
6495 Draw the text applying alpha blending. The value can
6496 be either a number between 0.0 and 1.0
6497 The expression accepts the same variables @var{x, y} do.
6498 The default value is 1.
6499 Please see fontcolor_expr
6502 The font size to be used for drawing text.
6503 The default value of @var{fontsize} is 16.
6506 If set to 1, attempt to shape the text (for example, reverse the order of
6507 right-to-left text and join Arabic characters) before drawing it.
6508 Otherwise, just draw the text exactly as given.
6509 By default 1 (if supported).
6512 The flags to be used for loading the fonts.
6514 The flags map the corresponding flags supported by libfreetype, and are
6515 a combination of the following values:
6522 @item vertical_layout
6523 @item force_autohint
6526 @item ignore_global_advance_width
6528 @item ignore_transform
6534 Default value is "default".
6536 For more information consult the documentation for the FT_LOAD_*
6540 The color to be used for drawing a shadow behind the drawn text. For the
6541 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
6543 The default value of @var{shadowcolor} is "black".
6547 The x and y offsets for the text shadow position with respect to the
6548 position of the text. They can be either positive or negative
6549 values. The default value for both is "0".
6552 The starting frame number for the n/frame_num variable. The default value
6556 The size in number of spaces to use for rendering the tab.
6560 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
6561 format. It can be used with or without text parameter. @var{timecode_rate}
6562 option must be specified.
6564 @item timecode_rate, rate, r
6565 Set the timecode frame rate (timecode only).
6568 The text string to be drawn. The text must be a sequence of UTF-8
6570 This parameter is mandatory if no file is specified with the parameter
6574 A text file containing text to be drawn. The text must be a sequence
6575 of UTF-8 encoded characters.
6577 This parameter is mandatory if no text string is specified with the
6578 parameter @var{text}.
6580 If both @var{text} and @var{textfile} are specified, an error is thrown.
6583 If set to 1, the @var{textfile} will be reloaded before each frame.
6584 Be sure to update it atomically, or it may be read partially, or even fail.
6588 The expressions which specify the offsets where text will be drawn
6589 within the video frame. They are relative to the top/left border of the
6592 The default value of @var{x} and @var{y} is "0".
6594 See below for the list of accepted constants and functions.
6597 The parameters for @var{x} and @var{y} are expressions containing the
6598 following constants and functions:
6602 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
6606 horizontal and vertical chroma subsample values. For example for the
6607 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6610 the height of each text line
6618 @item max_glyph_a, ascent
6619 the maximum distance from the baseline to the highest/upper grid
6620 coordinate used to place a glyph outline point, for all the rendered
6622 It is a positive value, due to the grid's orientation with the Y axis
6625 @item max_glyph_d, descent
6626 the maximum distance from the baseline to the lowest grid coordinate
6627 used to place a glyph outline point, for all the rendered glyphs.
6628 This is a negative value, due to the grid's orientation, with the Y axis
6632 maximum glyph height, that is the maximum height for all the glyphs
6633 contained in the rendered text, it is equivalent to @var{ascent} -
6637 maximum glyph width, that is the maximum width for all the glyphs
6638 contained in the rendered text
6641 the number of input frame, starting from 0
6643 @item rand(min, max)
6644 return a random number included between @var{min} and @var{max}
6647 The input sample aspect ratio.
6650 timestamp expressed in seconds, NAN if the input timestamp is unknown
6653 the height of the rendered text
6656 the width of the rendered text
6660 the x and y offset coordinates where the text is drawn.
6662 These parameters allow the @var{x} and @var{y} expressions to refer
6663 each other, so you can for example specify @code{y=x/dar}.
6666 @anchor{drawtext_expansion}
6667 @subsection Text expansion
6669 If @option{expansion} is set to @code{strftime},
6670 the filter recognizes strftime() sequences in the provided text and
6671 expands them accordingly. Check the documentation of strftime(). This
6672 feature is deprecated.
6674 If @option{expansion} is set to @code{none}, the text is printed verbatim.
6676 If @option{expansion} is set to @code{normal} (which is the default),
6677 the following expansion mechanism is used.
6679 The backslash character @samp{\}, followed by any character, always expands to
6680 the second character.
6682 Sequence of the form @code{%@{...@}} are expanded. The text between the
6683 braces is a function name, possibly followed by arguments separated by ':'.
6684 If the arguments contain special characters or delimiters (':' or '@}'),
6685 they should be escaped.
6687 Note that they probably must also be escaped as the value for the
6688 @option{text} option in the filter argument string and as the filter
6689 argument in the filtergraph description, and possibly also for the shell,
6690 that makes up to four levels of escaping; using a text file avoids these
6693 The following functions are available:
6698 The expression evaluation result.
6700 It must take one argument specifying the expression to be evaluated,
6701 which accepts the same constants and functions as the @var{x} and
6702 @var{y} values. Note that not all constants should be used, for
6703 example the text size is not known when evaluating the expression, so
6704 the constants @var{text_w} and @var{text_h} will have an undefined
6707 @item expr_int_format, eif
6708 Evaluate the expression's value and output as formatted integer.
6710 The first argument is the expression to be evaluated, just as for the @var{expr} function.
6711 The second argument specifies the output format. Allowed values are @samp{x},
6712 @samp{X}, @samp{d} and @samp{u}. They are treated exactly as in the
6713 @code{printf} function.
6714 The third parameter is optional and sets the number of positions taken by the output.
6715 It can be used to add padding with zeros from the left.
6718 The time at which the filter is running, expressed in UTC.
6719 It can accept an argument: a strftime() format string.
6722 The time at which the filter is running, expressed in the local time zone.
6723 It can accept an argument: a strftime() format string.
6726 Frame metadata. Takes one or two arguments.
6728 The first argument is mandatory and specifies the metadata key.
6730 The second argument is optional and specifies a default value, used when the
6731 metadata key is not found or empty.
6734 The frame number, starting from 0.
6737 A 1 character description of the current picture type.
6740 The timestamp of the current frame.
6741 It can take up to three arguments.
6743 The first argument is the format of the timestamp; it defaults to @code{flt}
6744 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
6745 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
6746 @code{gmtime} stands for the timestamp of the frame formatted as UTC time;
6747 @code{localtime} stands for the timestamp of the frame formatted as
6748 local time zone time.
6750 The second argument is an offset added to the timestamp.
6752 If the format is set to @code{localtime} or @code{gmtime},
6753 a third argument may be supplied: a strftime() format string.
6754 By default, @var{YYYY-MM-DD HH:MM:SS} format will be used.
6757 @subsection Examples
6761 Draw "Test Text" with font FreeSerif, using the default values for the
6762 optional parameters.
6765 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
6769 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
6770 and y=50 (counting from the top-left corner of the screen), text is
6771 yellow with a red box around it. Both the text and the box have an
6775 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
6776 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
6779 Note that the double quotes are not necessary if spaces are not used
6780 within the parameter list.
6783 Show the text at the center of the video frame:
6785 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h)/2"
6789 Show the text at a random position, switching to a new position every 30 seconds:
6791 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)"
6795 Show a text line sliding from right to left in the last row of the video
6796 frame. The file @file{LONG_LINE} is assumed to contain a single line
6799 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
6803 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
6805 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
6809 Draw a single green letter "g", at the center of the input video.
6810 The glyph baseline is placed at half screen height.
6812 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
6816 Show text for 1 second every 3 seconds:
6818 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
6822 Use fontconfig to set the font. Note that the colons need to be escaped.
6824 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
6828 Print the date of a real-time encoding (see strftime(3)):
6830 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
6834 Show text fading in and out (appearing/disappearing):
6837 DS=1.0 # display start
6838 DE=10.0 # display end
6839 FID=1.5 # fade in duration
6840 FOD=5 # fade out duration
6841 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 @}"
6846 For more information about libfreetype, check:
6847 @url{http://www.freetype.org/}.
6849 For more information about fontconfig, check:
6850 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
6852 For more information about libfribidi, check:
6853 @url{http://fribidi.org/}.
6857 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
6859 The filter accepts the following options:
6864 Set low and high threshold values used by the Canny thresholding
6867 The high threshold selects the "strong" edge pixels, which are then
6868 connected through 8-connectivity with the "weak" edge pixels selected
6869 by the low threshold.
6871 @var{low} and @var{high} threshold values must be chosen in the range
6872 [0,1], and @var{low} should be lesser or equal to @var{high}.
6874 Default value for @var{low} is @code{20/255}, and default value for @var{high}
6878 Define the drawing mode.
6882 Draw white/gray wires on black background.
6885 Mix the colors to create a paint/cartoon effect.
6888 Default value is @var{wires}.
6891 @subsection Examples
6895 Standard edge detection with custom values for the hysteresis thresholding:
6897 edgedetect=low=0.1:high=0.4
6901 Painting effect without thresholding:
6903 edgedetect=mode=colormix:high=0
6908 Set brightness, contrast, saturation and approximate gamma adjustment.
6910 The filter accepts the following options:
6914 Set the contrast expression. The value must be a float value in range
6915 @code{-2.0} to @code{2.0}. The default value is "1".
6918 Set the brightness expression. The value must be a float value in
6919 range @code{-1.0} to @code{1.0}. The default value is "0".
6922 Set the saturation expression. The value must be a float in
6923 range @code{0.0} to @code{3.0}. The default value is "1".
6926 Set the gamma expression. The value must be a float in range
6927 @code{0.1} to @code{10.0}. The default value is "1".
6930 Set the gamma expression for red. The value must be a float in
6931 range @code{0.1} to @code{10.0}. The default value is "1".
6934 Set the gamma expression for green. The value must be a float in range
6935 @code{0.1} to @code{10.0}. The default value is "1".
6938 Set the gamma expression for blue. The value must be a float in range
6939 @code{0.1} to @code{10.0}. The default value is "1".
6942 Set the gamma weight expression. It can be used to reduce the effect
6943 of a high gamma value on bright image areas, e.g. keep them from
6944 getting overamplified and just plain white. The value must be a float
6945 in range @code{0.0} to @code{1.0}. A value of @code{0.0} turns the
6946 gamma correction all the way down while @code{1.0} leaves it at its
6947 full strength. Default is "1".
6950 Set when the expressions for brightness, contrast, saturation and
6951 gamma expressions are evaluated.
6953 It accepts the following values:
6956 only evaluate expressions once during the filter initialization or
6957 when a command is processed
6960 evaluate expressions for each incoming frame
6963 Default value is @samp{init}.
6966 The expressions accept the following parameters:
6969 frame count of the input frame starting from 0
6972 byte position of the corresponding packet in the input file, NAN if
6976 frame rate of the input video, NAN if the input frame rate is unknown
6979 timestamp expressed in seconds, NAN if the input timestamp is unknown
6982 @subsection Commands
6983 The filter supports the following commands:
6987 Set the contrast expression.
6990 Set the brightness expression.
6993 Set the saturation expression.
6996 Set the gamma expression.
6999 Set the gamma_r expression.
7002 Set gamma_g expression.
7005 Set gamma_b expression.
7008 Set gamma_weight expression.
7010 The command accepts the same syntax of the corresponding option.
7012 If the specified expression is not valid, it is kept at its current
7019 Apply erosion effect to the video.
7021 This filter replaces the pixel by the local(3x3) minimum.
7023 It accepts the following options:
7030 Limit the maximum change for each plane, default is 65535.
7031 If 0, plane will remain unchanged.
7034 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
7037 Flags to local 3x3 coordinates maps like this:
7044 @section extractplanes
7046 Extract color channel components from input video stream into
7047 separate grayscale video streams.
7049 The filter accepts the following option:
7053 Set plane(s) to extract.
7055 Available values for planes are:
7066 Choosing planes not available in the input will result in an error.
7067 That means you cannot select @code{r}, @code{g}, @code{b} planes
7068 with @code{y}, @code{u}, @code{v} planes at same time.
7071 @subsection Examples
7075 Extract luma, u and v color channel component from input video frame
7076 into 3 grayscale outputs:
7078 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
7084 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
7086 For each input image, the filter will compute the optimal mapping from
7087 the input to the output given the codebook length, that is the number
7088 of distinct output colors.
7090 This filter accepts the following options.
7093 @item codebook_length, l
7094 Set codebook length. The value must be a positive integer, and
7095 represents the number of distinct output colors. Default value is 256.
7098 Set the maximum number of iterations to apply for computing the optimal
7099 mapping. The higher the value the better the result and the higher the
7100 computation time. Default value is 1.
7103 Set a random seed, must be an integer included between 0 and
7104 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
7105 will try to use a good random seed on a best effort basis.
7108 Set pal8 output pixel format. This option does not work with codebook
7109 length greater than 256.
7114 Apply a fade-in/out effect to the input video.
7116 It accepts the following parameters:
7120 The effect type can be either "in" for a fade-in, or "out" for a fade-out
7122 Default is @code{in}.
7124 @item start_frame, s
7125 Specify the number of the frame to start applying the fade
7126 effect at. Default is 0.
7129 The number of frames that the fade effect lasts. At the end of the
7130 fade-in effect, the output video will have the same intensity as the input video.
7131 At the end of the fade-out transition, the output video will be filled with the
7132 selected @option{color}.
7136 If set to 1, fade only alpha channel, if one exists on the input.
7139 @item start_time, st
7140 Specify the timestamp (in seconds) of the frame to start to apply the fade
7141 effect. If both start_frame and start_time are specified, the fade will start at
7142 whichever comes last. Default is 0.
7145 The number of seconds for which the fade effect has to last. At the end of the
7146 fade-in effect the output video will have the same intensity as the input video,
7147 at the end of the fade-out transition the output video will be filled with the
7148 selected @option{color}.
7149 If both duration and nb_frames are specified, duration is used. Default is 0
7150 (nb_frames is used by default).
7153 Specify the color of the fade. Default is "black".
7156 @subsection Examples
7160 Fade in the first 30 frames of video:
7165 The command above is equivalent to:
7171 Fade out the last 45 frames of a 200-frame video:
7174 fade=type=out:start_frame=155:nb_frames=45
7178 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
7180 fade=in:0:25, fade=out:975:25
7184 Make the first 5 frames yellow, then fade in from frame 5-24:
7186 fade=in:5:20:color=yellow
7190 Fade in alpha over first 25 frames of video:
7192 fade=in:0:25:alpha=1
7196 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
7198 fade=t=in:st=5.5:d=0.5
7204 Apply arbitrary expressions to samples in frequency domain
7208 Adjust the dc value (gain) of the luma plane of the image. The filter
7209 accepts an integer value in range @code{0} to @code{1000}. The default
7210 value is set to @code{0}.
7213 Adjust the dc value (gain) of the 1st chroma plane of the image. The
7214 filter accepts an integer value in range @code{0} to @code{1000}. The
7215 default value is set to @code{0}.
7218 Adjust the dc value (gain) of the 2nd chroma plane of the image. The
7219 filter accepts an integer value in range @code{0} to @code{1000}. The
7220 default value is set to @code{0}.
7223 Set the frequency domain weight expression for the luma plane.
7226 Set the frequency domain weight expression for the 1st chroma plane.
7229 Set the frequency domain weight expression for the 2nd chroma plane.
7231 The filter accepts the following variables:
7234 The coordinates of the current sample.
7238 The width and height of the image.
7241 @subsection Examples
7247 fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
7253 fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
7259 fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
7265 fftfilt=dc_Y=0:weight_Y='exp(-4 * ((Y+X)/(W+H)))'
7272 Extract a single field from an interlaced image using stride
7273 arithmetic to avoid wasting CPU time. The output frames are marked as
7276 The filter accepts the following options:
7280 Specify whether to extract the top (if the value is @code{0} or
7281 @code{top}) or the bottom field (if the value is @code{1} or
7287 Create new frames by copying the top and bottom fields from surrounding frames
7288 supplied as numbers by the hint file.
7292 Set file containing hints: absolute/relative frame numbers.
7294 There must be one line for each frame in a clip. Each line must contain two
7295 numbers separated by the comma, optionally followed by @code{-} or @code{+}.
7296 Numbers supplied on each line of file can not be out of [N-1,N+1] where N
7297 is current frame number for @code{absolute} mode or out of [-1, 1] range
7298 for @code{relative} mode. First number tells from which frame to pick up top
7299 field and second number tells from which frame to pick up bottom field.
7301 If optionally followed by @code{+} output frame will be marked as interlaced,
7302 else if followed by @code{-} output frame will be marked as progressive, else
7303 it will be marked same as input frame.
7304 If line starts with @code{#} or @code{;} that line is skipped.
7307 Can be item @code{absolute} or @code{relative}. Default is @code{absolute}.
7310 Example of first several lines of @code{hint} file for @code{relative} mode:
7313 1,0 - # second frame, use third's frame top field and second's frame bottom field
7314 1,0 - # third frame, use fourth's frame top field and third's frame bottom field
7331 Field matching filter for inverse telecine. It is meant to reconstruct the
7332 progressive frames from a telecined stream. The filter does not drop duplicated
7333 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
7334 followed by a decimation filter such as @ref{decimate} in the filtergraph.
7336 The separation of the field matching and the decimation is notably motivated by
7337 the possibility of inserting a de-interlacing filter fallback between the two.
7338 If the source has mixed telecined and real interlaced content,
7339 @code{fieldmatch} will not be able to match fields for the interlaced parts.
7340 But these remaining combed frames will be marked as interlaced, and thus can be
7341 de-interlaced by a later filter such as @ref{yadif} before decimation.
7343 In addition to the various configuration options, @code{fieldmatch} can take an
7344 optional second stream, activated through the @option{ppsrc} option. If
7345 enabled, the frames reconstruction will be based on the fields and frames from
7346 this second stream. This allows the first input to be pre-processed in order to
7347 help the various algorithms of the filter, while keeping the output lossless
7348 (assuming the fields are matched properly). Typically, a field-aware denoiser,
7349 or brightness/contrast adjustments can help.
7351 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
7352 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
7353 which @code{fieldmatch} is based on. While the semantic and usage are very
7354 close, some behaviour and options names can differ.
7356 The @ref{decimate} filter currently only works for constant frame rate input.
7357 If your input has mixed telecined (30fps) and progressive content with a lower
7358 framerate like 24fps use the following filterchain to produce the necessary cfr
7359 stream: @code{dejudder,fps=30000/1001,fieldmatch,decimate}.
7361 The filter accepts the following options:
7365 Specify the assumed field order of the input stream. Available values are:
7369 Auto detect parity (use FFmpeg's internal parity value).
7371 Assume bottom field first.
7373 Assume top field first.
7376 Note that it is sometimes recommended not to trust the parity announced by the
7379 Default value is @var{auto}.
7382 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
7383 sense that it won't risk creating jerkiness due to duplicate frames when
7384 possible, but if there are bad edits or blended fields it will end up
7385 outputting combed frames when a good match might actually exist. On the other
7386 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
7387 but will almost always find a good frame if there is one. The other values are
7388 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
7389 jerkiness and creating duplicate frames versus finding good matches in sections
7390 with bad edits, orphaned fields, blended fields, etc.
7392 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
7394 Available values are:
7398 2-way matching (p/c)
7400 2-way matching, and trying 3rd match if still combed (p/c + n)
7402 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
7404 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
7405 still combed (p/c + n + u/b)
7407 3-way matching (p/c/n)
7409 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
7410 detected as combed (p/c/n + u/b)
7413 The parenthesis at the end indicate the matches that would be used for that
7414 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
7417 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
7420 Default value is @var{pc_n}.
7423 Mark the main input stream as a pre-processed input, and enable the secondary
7424 input stream as the clean source to pick the fields from. See the filter
7425 introduction for more details. It is similar to the @option{clip2} feature from
7428 Default value is @code{0} (disabled).
7431 Set the field to match from. It is recommended to set this to the same value as
7432 @option{order} unless you experience matching failures with that setting. In
7433 certain circumstances changing the field that is used to match from can have a
7434 large impact on matching performance. Available values are:
7438 Automatic (same value as @option{order}).
7440 Match from the bottom field.
7442 Match from the top field.
7445 Default value is @var{auto}.
7448 Set whether or not chroma is included during the match comparisons. In most
7449 cases it is recommended to leave this enabled. You should set this to @code{0}
7450 only if your clip has bad chroma problems such as heavy rainbowing or other
7451 artifacts. Setting this to @code{0} could also be used to speed things up at
7452 the cost of some accuracy.
7454 Default value is @code{1}.
7458 These define an exclusion band which excludes the lines between @option{y0} and
7459 @option{y1} from being included in the field matching decision. An exclusion
7460 band can be used to ignore subtitles, a logo, or other things that may
7461 interfere with the matching. @option{y0} sets the starting scan line and
7462 @option{y1} sets the ending line; all lines in between @option{y0} and
7463 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
7464 @option{y0} and @option{y1} to the same value will disable the feature.
7465 @option{y0} and @option{y1} defaults to @code{0}.
7468 Set the scene change detection threshold as a percentage of maximum change on
7469 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
7470 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
7471 @option{scthresh} is @code{[0.0, 100.0]}.
7473 Default value is @code{12.0}.
7476 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
7477 account the combed scores of matches when deciding what match to use as the
7478 final match. Available values are:
7482 No final matching based on combed scores.
7484 Combed scores are only used when a scene change is detected.
7486 Use combed scores all the time.
7489 Default is @var{sc}.
7492 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
7493 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
7494 Available values are:
7498 No forced calculation.
7500 Force p/c/n calculations.
7502 Force p/c/n/u/b calculations.
7505 Default value is @var{none}.
7508 This is the area combing threshold used for combed frame detection. This
7509 essentially controls how "strong" or "visible" combing must be to be detected.
7510 Larger values mean combing must be more visible and smaller values mean combing
7511 can be less visible or strong and still be detected. Valid settings are from
7512 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
7513 be detected as combed). This is basically a pixel difference value. A good
7514 range is @code{[8, 12]}.
7516 Default value is @code{9}.
7519 Sets whether or not chroma is considered in the combed frame decision. Only
7520 disable this if your source has chroma problems (rainbowing, etc.) that are
7521 causing problems for the combed frame detection with chroma enabled. Actually,
7522 using @option{chroma}=@var{0} is usually more reliable, except for the case
7523 where there is chroma only combing in the source.
7525 Default value is @code{0}.
7529 Respectively set the x-axis and y-axis size of the window used during combed
7530 frame detection. This has to do with the size of the area in which
7531 @option{combpel} pixels are required to be detected as combed for a frame to be
7532 declared combed. See the @option{combpel} parameter description for more info.
7533 Possible values are any number that is a power of 2 starting at 4 and going up
7536 Default value is @code{16}.
7539 The number of combed pixels inside any of the @option{blocky} by
7540 @option{blockx} size blocks on the frame for the frame to be detected as
7541 combed. While @option{cthresh} controls how "visible" the combing must be, this
7542 setting controls "how much" combing there must be in any localized area (a
7543 window defined by the @option{blockx} and @option{blocky} settings) on the
7544 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
7545 which point no frames will ever be detected as combed). This setting is known
7546 as @option{MI} in TFM/VFM vocabulary.
7548 Default value is @code{80}.
7551 @anchor{p/c/n/u/b meaning}
7552 @subsection p/c/n/u/b meaning
7554 @subsubsection p/c/n
7556 We assume the following telecined stream:
7559 Top fields: 1 2 2 3 4
7560 Bottom fields: 1 2 3 4 4
7563 The numbers correspond to the progressive frame the fields relate to. Here, the
7564 first two frames are progressive, the 3rd and 4th are combed, and so on.
7566 When @code{fieldmatch} is configured to run a matching from bottom
7567 (@option{field}=@var{bottom}) this is how this input stream get transformed:
7572 B 1 2 3 4 4 <-- matching reference
7581 As a result of the field matching, we can see that some frames get duplicated.
7582 To perform a complete inverse telecine, you need to rely on a decimation filter
7583 after this operation. See for instance the @ref{decimate} filter.
7585 The same operation now matching from top fields (@option{field}=@var{top})
7590 T 1 2 2 3 4 <-- matching reference
7600 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
7601 basically, they refer to the frame and field of the opposite parity:
7604 @item @var{p} matches the field of the opposite parity in the previous frame
7605 @item @var{c} matches the field of the opposite parity in the current frame
7606 @item @var{n} matches the field of the opposite parity in the next frame
7611 The @var{u} and @var{b} matching are a bit special in the sense that they match
7612 from the opposite parity flag. In the following examples, we assume that we are
7613 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
7614 'x' is placed above and below each matched fields.
7616 With bottom matching (@option{field}=@var{bottom}):
7621 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
7622 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
7630 With top matching (@option{field}=@var{top}):
7635 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
7636 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
7644 @subsection Examples
7646 Simple IVTC of a top field first telecined stream:
7648 fieldmatch=order=tff:combmatch=none, decimate
7651 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
7653 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
7658 Transform the field order of the input video.
7660 It accepts the following parameters:
7665 The output field order. Valid values are @var{tff} for top field first or @var{bff}
7666 for bottom field first.
7669 The default value is @samp{tff}.
7671 The transformation is done by shifting the picture content up or down
7672 by one line, and filling the remaining line with appropriate picture content.
7673 This method is consistent with most broadcast field order converters.
7675 If the input video is not flagged as being interlaced, or it is already
7676 flagged as being of the required output field order, then this filter does
7677 not alter the incoming video.
7679 It is very useful when converting to or from PAL DV material,
7680 which is bottom field first.
7684 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
7687 @section fifo, afifo
7689 Buffer input images and send them when they are requested.
7691 It is mainly useful when auto-inserted by the libavfilter
7694 It does not take parameters.
7698 Find a rectangular object
7700 It accepts the following options:
7704 Filepath of the object image, needs to be in gray8.
7707 Detection threshold, default is 0.5.
7710 Number of mipmaps, default is 3.
7712 @item xmin, ymin, xmax, ymax
7713 Specifies the rectangle in which to search.
7716 @subsection Examples
7720 Generate a representative palette of a given video using @command{ffmpeg}:
7722 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
7728 Cover a rectangular object
7730 It accepts the following options:
7734 Filepath of the optional cover image, needs to be in yuv420.
7739 It accepts the following values:
7742 cover it by the supplied image
7744 cover it by interpolating the surrounding pixels
7747 Default value is @var{blur}.
7750 @subsection Examples
7754 Generate a representative palette of a given video using @command{ffmpeg}:
7756 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
7763 Convert the input video to one of the specified pixel formats.
7764 Libavfilter will try to pick one that is suitable as input to
7767 It accepts the following parameters:
7771 A '|'-separated list of pixel format names, such as
7772 "pix_fmts=yuv420p|monow|rgb24".
7776 @subsection Examples
7780 Convert the input video to the @var{yuv420p} format
7782 format=pix_fmts=yuv420p
7785 Convert the input video to any of the formats in the list
7787 format=pix_fmts=yuv420p|yuv444p|yuv410p
7794 Convert the video to specified constant frame rate by duplicating or dropping
7795 frames as necessary.
7797 It accepts the following parameters:
7801 The desired output frame rate. The default is @code{25}.
7806 Possible values are:
7809 zero round towards 0
7813 round towards -infinity
7815 round towards +infinity
7819 The default is @code{near}.
7822 Assume the first PTS should be the given value, in seconds. This allows for
7823 padding/trimming at the start of stream. By default, no assumption is made
7824 about the first frame's expected PTS, so no padding or trimming is done.
7825 For example, this could be set to 0 to pad the beginning with duplicates of
7826 the first frame if a video stream starts after the audio stream or to trim any
7827 frames with a negative PTS.
7831 Alternatively, the options can be specified as a flat string:
7832 @var{fps}[:@var{round}].
7834 See also the @ref{setpts} filter.
7836 @subsection Examples
7840 A typical usage in order to set the fps to 25:
7846 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
7848 fps=fps=film:round=near
7854 Pack two different video streams into a stereoscopic video, setting proper
7855 metadata on supported codecs. The two views should have the same size and
7856 framerate and processing will stop when the shorter video ends. Please note
7857 that you may conveniently adjust view properties with the @ref{scale} and
7860 It accepts the following parameters:
7864 The desired packing format. Supported values are:
7869 The views are next to each other (default).
7872 The views are on top of each other.
7875 The views are packed by line.
7878 The views are packed by column.
7881 The views are temporally interleaved.
7890 # Convert left and right views into a frame-sequential video
7891 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
7893 # Convert views into a side-by-side video with the same output resolution as the input
7894 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
7899 Change the frame rate by interpolating new video output frames from the source
7902 This filter is not designed to function correctly with interlaced media. If
7903 you wish to change the frame rate of interlaced media then you are required
7904 to deinterlace before this filter and re-interlace after this filter.
7906 A description of the accepted options follows.
7910 Specify the output frames per second. This option can also be specified
7911 as a value alone. The default is @code{50}.
7914 Specify the start of a range where the output frame will be created as a
7915 linear interpolation of two frames. The range is [@code{0}-@code{255}],
7916 the default is @code{15}.
7919 Specify the end of a range where the output frame will be created as a
7920 linear interpolation of two frames. The range is [@code{0}-@code{255}],
7921 the default is @code{240}.
7924 Specify the level at which a scene change is detected as a value between
7925 0 and 100 to indicate a new scene; a low value reflects a low
7926 probability for the current frame to introduce a new scene, while a higher
7927 value means the current frame is more likely to be one.
7928 The default is @code{7}.
7931 Specify flags influencing the filter process.
7933 Available value for @var{flags} is:
7936 @item scene_change_detect, scd
7937 Enable scene change detection using the value of the option @var{scene}.
7938 This flag is enabled by default.
7944 Select one frame every N-th frame.
7946 This filter accepts the following option:
7949 Select frame after every @code{step} frames.
7950 Allowed values are positive integers higher than 0. Default value is @code{1}.
7956 Apply a frei0r effect to the input video.
7958 To enable the compilation of this filter, you need to install the frei0r
7959 header and configure FFmpeg with @code{--enable-frei0r}.
7961 It accepts the following parameters:
7966 The name of the frei0r effect to load. If the environment variable
7967 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
7968 directories specified by the colon-separated list in @env{FREIOR_PATH}.
7969 Otherwise, the standard frei0r paths are searched, in this order:
7970 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
7971 @file{/usr/lib/frei0r-1/}.
7974 A '|'-separated list of parameters to pass to the frei0r effect.
7978 A frei0r effect parameter can be a boolean (its value is either
7979 "y" or "n"), a double, a color (specified as
7980 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
7981 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
7982 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
7983 @var{X} and @var{Y} are floating point numbers) and/or a string.
7985 The number and types of parameters depend on the loaded effect. If an
7986 effect parameter is not specified, the default value is set.
7988 @subsection Examples
7992 Apply the distort0r effect, setting the first two double parameters:
7994 frei0r=filter_name=distort0r:filter_params=0.5|0.01
7998 Apply the colordistance effect, taking a color as the first parameter:
8000 frei0r=colordistance:0.2/0.3/0.4
8001 frei0r=colordistance:violet
8002 frei0r=colordistance:0x112233
8006 Apply the perspective effect, specifying the top left and top right image
8009 frei0r=perspective:0.2/0.2|0.8/0.2
8013 For more information, see
8014 @url{http://frei0r.dyne.org}
8018 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
8020 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
8021 processing filter, one of them is performed once per block, not per pixel.
8022 This allows for much higher speed.
8024 The filter accepts the following options:
8028 Set quality. This option defines the number of levels for averaging. It accepts
8029 an integer in the range 4-5. Default value is @code{4}.
8032 Force a constant quantization parameter. It accepts an integer in range 0-63.
8033 If not set, the filter will use the QP from the video stream (if available).
8036 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
8037 more details but also more artifacts, while higher values make the image smoother
8038 but also blurrier. Default value is @code{0} − PSNR optimal.
8041 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8042 option may cause flicker since the B-Frames have often larger QP. Default is
8043 @code{0} (not enabled).
8049 The filter accepts the following options:
8053 Set the luminance expression.
8055 Set the chrominance blue expression.
8057 Set the chrominance red expression.
8059 Set the alpha expression.
8061 Set the red expression.
8063 Set the green expression.
8065 Set the blue expression.
8068 The colorspace is selected according to the specified options. If one
8069 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
8070 options is specified, the filter will automatically select a YCbCr
8071 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
8072 @option{blue_expr} options is specified, it will select an RGB
8075 If one of the chrominance expression is not defined, it falls back on the other
8076 one. If no alpha expression is specified it will evaluate to opaque value.
8077 If none of chrominance expressions are specified, they will evaluate
8078 to the luminance expression.
8080 The expressions can use the following variables and functions:
8084 The sequential number of the filtered frame, starting from @code{0}.
8088 The coordinates of the current sample.
8092 The width and height of the image.
8096 Width and height scale depending on the currently filtered plane. It is the
8097 ratio between the corresponding luma plane number of pixels and the current
8098 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
8099 @code{0.5,0.5} for chroma planes.
8102 Time of the current frame, expressed in seconds.
8105 Return the value of the pixel at location (@var{x},@var{y}) of the current
8109 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
8113 Return the value of the pixel at location (@var{x},@var{y}) of the
8114 blue-difference chroma plane. Return 0 if there is no such plane.
8117 Return the value of the pixel at location (@var{x},@var{y}) of the
8118 red-difference chroma plane. Return 0 if there is no such plane.
8123 Return the value of the pixel at location (@var{x},@var{y}) of the
8124 red/green/blue component. Return 0 if there is no such component.
8127 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
8128 plane. Return 0 if there is no such plane.
8131 For functions, if @var{x} and @var{y} are outside the area, the value will be
8132 automatically clipped to the closer edge.
8134 @subsection Examples
8138 Flip the image horizontally:
8144 Generate a bidimensional sine wave, with angle @code{PI/3} and a
8145 wavelength of 100 pixels:
8147 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
8151 Generate a fancy enigmatic moving light:
8153 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
8157 Generate a quick emboss effect:
8159 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
8163 Modify RGB components depending on pixel position:
8165 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
8169 Create a radial gradient that is the same size as the input (also see
8170 the @ref{vignette} filter):
8172 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
8178 Fix the banding artifacts that are sometimes introduced into nearly flat
8179 regions by truncation to 8bit color depth.
8180 Interpolate the gradients that should go where the bands are, and
8183 It is designed for playback only. Do not use it prior to
8184 lossy compression, because compression tends to lose the dither and
8185 bring back the bands.
8187 It accepts the following parameters:
8192 The maximum amount by which the filter will change any one pixel. This is also
8193 the threshold for detecting nearly flat regions. Acceptable values range from
8194 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
8198 The neighborhood to fit the gradient to. A larger radius makes for smoother
8199 gradients, but also prevents the filter from modifying the pixels near detailed
8200 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
8201 values will be clipped to the valid range.
8205 Alternatively, the options can be specified as a flat string:
8206 @var{strength}[:@var{radius}]
8208 @subsection Examples
8212 Apply the filter with a @code{3.5} strength and radius of @code{8}:
8218 Specify radius, omitting the strength (which will fall-back to the default
8229 Apply a Hald CLUT to a video stream.
8231 First input is the video stream to process, and second one is the Hald CLUT.
8232 The Hald CLUT input can be a simple picture or a complete video stream.
8234 The filter accepts the following options:
8238 Force termination when the shortest input terminates. Default is @code{0}.
8240 Continue applying the last CLUT after the end of the stream. A value of
8241 @code{0} disable the filter after the last frame of the CLUT is reached.
8242 Default is @code{1}.
8245 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
8246 filters share the same internals).
8248 More information about the Hald CLUT can be found on Eskil Steenberg's website
8249 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
8251 @subsection Workflow examples
8253 @subsubsection Hald CLUT video stream
8255 Generate an identity Hald CLUT stream altered with various effects:
8257 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
8260 Note: make sure you use a lossless codec.
8262 Then use it with @code{haldclut} to apply it on some random stream:
8264 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
8267 The Hald CLUT will be applied to the 10 first seconds (duration of
8268 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
8269 to the remaining frames of the @code{mandelbrot} stream.
8271 @subsubsection Hald CLUT with preview
8273 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
8274 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
8275 biggest possible square starting at the top left of the picture. The remaining
8276 padding pixels (bottom or right) will be ignored. This area can be used to add
8277 a preview of the Hald CLUT.
8279 Typically, the following generated Hald CLUT will be supported by the
8280 @code{haldclut} filter:
8283 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
8284 pad=iw+320 [padded_clut];
8285 smptebars=s=320x256, split [a][b];
8286 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
8287 [main][b] overlay=W-320" -frames:v 1 clut.png
8290 It contains the original and a preview of the effect of the CLUT: SMPTE color
8291 bars are displayed on the right-top, and below the same color bars processed by
8294 Then, the effect of this Hald CLUT can be visualized with:
8296 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
8301 Decodes high definition audio cd data. 16-Bit PCM stream containing hdcd flags
8302 is converted to 20-bit PCM stream.
8306 Flip the input video horizontally.
8308 For example, to horizontally flip the input video with @command{ffmpeg}:
8310 ffmpeg -i in.avi -vf "hflip" out.avi
8314 This filter applies a global color histogram equalization on a
8317 It can be used to correct video that has a compressed range of pixel
8318 intensities. The filter redistributes the pixel intensities to
8319 equalize their distribution across the intensity range. It may be
8320 viewed as an "automatically adjusting contrast filter". This filter is
8321 useful only for correcting degraded or poorly captured source
8324 The filter accepts the following options:
8328 Determine the amount of equalization to be applied. As the strength
8329 is reduced, the distribution of pixel intensities more-and-more
8330 approaches that of the input frame. The value must be a float number
8331 in the range [0,1] and defaults to 0.200.
8334 Set the maximum intensity that can generated and scale the output
8335 values appropriately. The strength should be set as desired and then
8336 the intensity can be limited if needed to avoid washing-out. The value
8337 must be a float number in the range [0,1] and defaults to 0.210.
8340 Set the antibanding level. If enabled the filter will randomly vary
8341 the luminance of output pixels by a small amount to avoid banding of
8342 the histogram. Possible values are @code{none}, @code{weak} or
8343 @code{strong}. It defaults to @code{none}.
8348 Compute and draw a color distribution histogram for the input video.
8350 The computed histogram is a representation of the color component
8351 distribution in an image.
8353 Standard histogram displays the color components distribution in an image.
8354 Displays color graph for each color component. Shows distribution of
8355 the Y, U, V, A or R, G, B components, depending on input format, in the
8356 current frame. Below each graph a color component scale meter is shown.
8358 The filter accepts the following options:
8362 Set height of level. Default value is @code{200}.
8363 Allowed range is [50, 2048].
8366 Set height of color scale. Default value is @code{12}.
8367 Allowed range is [0, 40].
8371 It accepts the following values:
8374 Per color component graphs are placed below each other.
8377 Presents information identical to that in the @code{parade}, except
8378 that the graphs representing color components are superimposed directly
8381 Default is @code{parade}.
8384 Set mode. Can be either @code{linear}, or @code{logarithmic}.
8385 Default is @code{linear}.
8388 Set what color components to display.
8389 Default is @code{7}.
8392 @subsection Examples
8397 Calculate and draw histogram:
8399 ffplay -i input -vf histogram
8407 This is a high precision/quality 3d denoise filter. It aims to reduce
8408 image noise, producing smooth images and making still images really
8409 still. It should enhance compressibility.
8411 It accepts the following optional parameters:
8415 A non-negative floating point number which specifies spatial luma strength.
8418 @item chroma_spatial
8419 A non-negative floating point number which specifies spatial chroma strength.
8420 It defaults to 3.0*@var{luma_spatial}/4.0.
8423 A floating point number which specifies luma temporal strength. It defaults to
8424 6.0*@var{luma_spatial}/4.0.
8427 A floating point number which specifies chroma temporal strength. It defaults to
8428 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
8431 @anchor{hwupload_cuda}
8432 @section hwupload_cuda
8434 Upload system memory frames to a CUDA device.
8436 It accepts the following optional parameters:
8440 The number of the CUDA device to use
8445 Apply a high-quality magnification filter designed for pixel art. This filter
8446 was originally created by Maxim Stepin.
8448 It accepts the following option:
8452 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
8453 @code{hq3x} and @code{4} for @code{hq4x}.
8454 Default is @code{3}.
8458 Stack input videos horizontally.
8460 All streams must be of same pixel format and of same height.
8462 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
8463 to create same output.
8465 The filter accept the following option:
8469 Set number of input streams. Default is 2.
8472 If set to 1, force the output to terminate when the shortest input
8473 terminates. Default value is 0.
8478 Modify the hue and/or the saturation of the input.
8480 It accepts the following parameters:
8484 Specify the hue angle as a number of degrees. It accepts an expression,
8485 and defaults to "0".
8488 Specify the saturation in the [-10,10] range. It accepts an expression and
8492 Specify the hue angle as a number of radians. It accepts an
8493 expression, and defaults to "0".
8496 Specify the brightness in the [-10,10] range. It accepts an expression and
8500 @option{h} and @option{H} are mutually exclusive, and can't be
8501 specified at the same time.
8503 The @option{b}, @option{h}, @option{H} and @option{s} option values are
8504 expressions containing the following constants:
8508 frame count of the input frame starting from 0
8511 presentation timestamp of the input frame expressed in time base units
8514 frame rate of the input video, NAN if the input frame rate is unknown
8517 timestamp expressed in seconds, NAN if the input timestamp is unknown
8520 time base of the input video
8523 @subsection Examples
8527 Set the hue to 90 degrees and the saturation to 1.0:
8533 Same command but expressing the hue in radians:
8539 Rotate hue and make the saturation swing between 0
8540 and 2 over a period of 1 second:
8542 hue="H=2*PI*t: s=sin(2*PI*t)+1"
8546 Apply a 3 seconds saturation fade-in effect starting at 0:
8551 The general fade-in expression can be written as:
8553 hue="s=min(0\, max((t-START)/DURATION\, 1))"
8557 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
8559 hue="s=max(0\, min(1\, (8-t)/3))"
8562 The general fade-out expression can be written as:
8564 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
8569 @subsection Commands
8571 This filter supports the following commands:
8577 Modify the hue and/or the saturation and/or brightness of the input video.
8578 The command accepts the same syntax of the corresponding option.
8580 If the specified expression is not valid, it is kept at its current
8586 Detect video interlacing type.
8588 This filter tries to detect if the input frames as interlaced, progressive,
8589 top or bottom field first. It will also try and detect fields that are
8590 repeated between adjacent frames (a sign of telecine).
8592 Single frame detection considers only immediately adjacent frames when classifying each frame.
8593 Multiple frame detection incorporates the classification history of previous frames.
8595 The filter will log these metadata values:
8598 @item single.current_frame
8599 Detected type of current frame using single-frame detection. One of:
8600 ``tff'' (top field first), ``bff'' (bottom field first),
8601 ``progressive'', or ``undetermined''
8604 Cumulative number of frames detected as top field first using single-frame detection.
8607 Cumulative number of frames detected as top field first using multiple-frame detection.
8610 Cumulative number of frames detected as bottom field first using single-frame detection.
8612 @item multiple.current_frame
8613 Detected type of current frame using multiple-frame detection. One of:
8614 ``tff'' (top field first), ``bff'' (bottom field first),
8615 ``progressive'', or ``undetermined''
8618 Cumulative number of frames detected as bottom field first using multiple-frame detection.
8620 @item single.progressive
8621 Cumulative number of frames detected as progressive using single-frame detection.
8623 @item multiple.progressive
8624 Cumulative number of frames detected as progressive using multiple-frame detection.
8626 @item single.undetermined
8627 Cumulative number of frames that could not be classified using single-frame detection.
8629 @item multiple.undetermined
8630 Cumulative number of frames that could not be classified using multiple-frame detection.
8632 @item repeated.current_frame
8633 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
8635 @item repeated.neither
8636 Cumulative number of frames with no repeated field.
8639 Cumulative number of frames with the top field repeated from the previous frame's top field.
8641 @item repeated.bottom
8642 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
8645 The filter accepts the following options:
8649 Set interlacing threshold.
8651 Set progressive threshold.
8653 Threshold for repeated field detection.
8655 Number of frames after which a given frame's contribution to the
8656 statistics is halved (i.e., it contributes only 0.5 to it's
8657 classification). The default of 0 means that all frames seen are given
8658 full weight of 1.0 forever.
8659 @item analyze_interlaced_flag
8660 When this is not 0 then idet will use the specified number of frames to determine
8661 if the interlaced flag is accurate, it will not count undetermined frames.
8662 If the flag is found to be accurate it will be used without any further
8663 computations, if it is found to be inaccurate it will be cleared without any
8664 further computations. This allows inserting the idet filter as a low computational
8665 method to clean up the interlaced flag
8670 Deinterleave or interleave fields.
8672 This filter allows one to process interlaced images fields without
8673 deinterlacing them. Deinterleaving splits the input frame into 2
8674 fields (so called half pictures). Odd lines are moved to the top
8675 half of the output image, even lines to the bottom half.
8676 You can process (filter) them independently and then re-interleave them.
8678 The filter accepts the following options:
8682 @item chroma_mode, c
8684 Available values for @var{luma_mode}, @var{chroma_mode} and
8685 @var{alpha_mode} are:
8691 @item deinterleave, d
8692 Deinterleave fields, placing one above the other.
8695 Interleave fields. Reverse the effect of deinterleaving.
8697 Default value is @code{none}.
8700 @item chroma_swap, cs
8701 @item alpha_swap, as
8702 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
8707 Apply inflate effect to the video.
8709 This filter replaces the pixel by the local(3x3) average by taking into account
8710 only values higher than the pixel.
8712 It accepts the following options:
8719 Limit the maximum change for each plane, default is 65535.
8720 If 0, plane will remain unchanged.
8725 Simple interlacing filter from progressive contents. This interleaves upper (or
8726 lower) lines from odd frames with lower (or upper) lines from even frames,
8727 halving the frame rate and preserving image height.
8730 Original Original New Frame
8731 Frame 'j' Frame 'j+1' (tff)
8732 ========== =========== ==================
8733 Line 0 --------------------> Frame 'j' Line 0
8734 Line 1 Line 1 ----> Frame 'j+1' Line 1
8735 Line 2 ---------------------> Frame 'j' Line 2
8736 Line 3 Line 3 ----> Frame 'j+1' Line 3
8738 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
8741 It accepts the following optional parameters:
8745 This determines whether the interlaced frame is taken from the even
8746 (tff - default) or odd (bff) lines of the progressive frame.
8749 Enable (default) or disable the vertical lowpass filter to avoid twitter
8750 interlacing and reduce moire patterns.
8755 Deinterlace input video by applying Donald Graft's adaptive kernel
8756 deinterling. Work on interlaced parts of a video to produce
8759 The description of the accepted parameters follows.
8763 Set the threshold which affects the filter's tolerance when
8764 determining if a pixel line must be processed. It must be an integer
8765 in the range [0,255] and defaults to 10. A value of 0 will result in
8766 applying the process on every pixels.
8769 Paint pixels exceeding the threshold value to white if set to 1.
8773 Set the fields order. Swap fields if set to 1, leave fields alone if
8777 Enable additional sharpening if set to 1. Default is 0.
8780 Enable twoway sharpening if set to 1. Default is 0.
8783 @subsection Examples
8787 Apply default values:
8789 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
8793 Enable additional sharpening:
8799 Paint processed pixels in white:
8805 @section lenscorrection
8807 Correct radial lens distortion
8809 This filter can be used to correct for radial distortion as can result from the use
8810 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
8811 one can use tools available for example as part of opencv or simply trial-and-error.
8812 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
8813 and extract the k1 and k2 coefficients from the resulting matrix.
8815 Note that effectively the same filter is available in the open-source tools Krita and
8816 Digikam from the KDE project.
8818 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
8819 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
8820 brightness distribution, so you may want to use both filters together in certain
8821 cases, though you will have to take care of ordering, i.e. whether vignetting should
8822 be applied before or after lens correction.
8826 The filter accepts the following options:
8830 Relative x-coordinate of the focal point of the image, and thereby the center of the
8831 distortion. This value has a range [0,1] and is expressed as fractions of the image
8834 Relative y-coordinate of the focal point of the image, and thereby the center of the
8835 distortion. This value has a range [0,1] and is expressed as fractions of the image
8838 Coefficient of the quadratic correction term. 0.5 means no correction.
8840 Coefficient of the double quadratic correction term. 0.5 means no correction.
8843 The formula that generates the correction is:
8845 @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)
8847 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
8848 distances from the focal point in the source and target images, respectively.
8850 @section loop, aloop
8852 Loop video frames or audio samples.
8854 Those filters accepts the following options:
8858 Set the number of loops.
8861 Set maximal size in number of frames for @code{loop} filter or maximal number
8862 of samples in case of @code{aloop} filter.
8865 Set first frame of loop for @code{loop} filter or first sample of loop in case
8866 of @code{aloop} filter.
8872 Apply a 3D LUT to an input video.
8874 The filter accepts the following options:
8878 Set the 3D LUT file name.
8880 Currently supported formats:
8892 Select interpolation mode.
8894 Available values are:
8898 Use values from the nearest defined point.
8900 Interpolate values using the 8 points defining a cube.
8902 Interpolate values using a tetrahedron.
8906 @section lut, lutrgb, lutyuv
8908 Compute a look-up table for binding each pixel component input value
8909 to an output value, and apply it to the input video.
8911 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
8912 to an RGB input video.
8914 These filters accept the following parameters:
8917 set first pixel component expression
8919 set second pixel component expression
8921 set third pixel component expression
8923 set fourth pixel component expression, corresponds to the alpha component
8926 set red component expression
8928 set green component expression
8930 set blue component expression
8932 alpha component expression
8935 set Y/luminance component expression
8937 set U/Cb component expression
8939 set V/Cr component expression
8942 Each of them specifies the expression to use for computing the lookup table for
8943 the corresponding pixel component values.
8945 The exact component associated to each of the @var{c*} options depends on the
8948 The @var{lut} filter requires either YUV or RGB pixel formats in input,
8949 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
8951 The expressions can contain the following constants and functions:
8956 The input width and height.
8959 The input value for the pixel component.
8962 The input value, clipped to the @var{minval}-@var{maxval} range.
8965 The maximum value for the pixel component.
8968 The minimum value for the pixel component.
8971 The negated value for the pixel component value, clipped to the
8972 @var{minval}-@var{maxval} range; it corresponds to the expression
8973 "maxval-clipval+minval".
8976 The computed value in @var{val}, clipped to the
8977 @var{minval}-@var{maxval} range.
8979 @item gammaval(gamma)
8980 The computed gamma correction value of the pixel component value,
8981 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
8983 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
8987 All expressions default to "val".
8989 @subsection Examples
8995 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
8996 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
8999 The above is the same as:
9001 lutrgb="r=negval:g=negval:b=negval"
9002 lutyuv="y=negval:u=negval:v=negval"
9012 Remove chroma components, turning the video into a graytone image:
9014 lutyuv="u=128:v=128"
9018 Apply a luma burning effect:
9024 Remove green and blue components:
9030 Set a constant alpha channel value on input:
9032 format=rgba,lutrgb=a="maxval-minval/2"
9036 Correct luminance gamma by a factor of 0.5:
9038 lutyuv=y=gammaval(0.5)
9042 Discard least significant bits of luma:
9044 lutyuv=y='bitand(val, 128+64+32)'
9048 @section maskedmerge
9050 Merge the first input stream with the second input stream using per pixel
9051 weights in the third input stream.
9053 A value of 0 in the third stream pixel component means that pixel component
9054 from first stream is returned unchanged, while maximum value (eg. 255 for
9055 8-bit videos) means that pixel component from second stream is returned
9056 unchanged. Intermediate values define the amount of merging between both
9057 input stream's pixel components.
9059 This filter accepts the following options:
9062 Set which planes will be processed as bitmap, unprocessed planes will be
9063 copied from first stream.
9064 By default value 0xf, all planes will be processed.
9069 Apply motion-compensation deinterlacing.
9071 It needs one field per frame as input and must thus be used together
9072 with yadif=1/3 or equivalent.
9074 This filter accepts the following options:
9077 Set the deinterlacing mode.
9079 It accepts one of the following values:
9084 use iterative motion estimation
9086 like @samp{slow}, but use multiple reference frames.
9088 Default value is @samp{fast}.
9091 Set the picture field parity assumed for the input video. It must be
9092 one of the following values:
9096 assume top field first
9098 assume bottom field first
9101 Default value is @samp{bff}.
9104 Set per-block quantization parameter (QP) used by the internal
9107 Higher values should result in a smoother motion vector field but less
9108 optimal individual vectors. Default value is 1.
9111 @section mergeplanes
9113 Merge color channel components from several video streams.
9115 The filter accepts up to 4 input streams, and merge selected input
9116 planes to the output video.
9118 This filter accepts the following options:
9121 Set input to output plane mapping. Default is @code{0}.
9123 The mappings is specified as a bitmap. It should be specified as a
9124 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
9125 mapping for the first plane of the output stream. 'A' sets the number of
9126 the input stream to use (from 0 to 3), and 'a' the plane number of the
9127 corresponding input to use (from 0 to 3). The rest of the mappings is
9128 similar, 'Bb' describes the mapping for the output stream second
9129 plane, 'Cc' describes the mapping for the output stream third plane and
9130 'Dd' describes the mapping for the output stream fourth plane.
9133 Set output pixel format. Default is @code{yuva444p}.
9136 @subsection Examples
9140 Merge three gray video streams of same width and height into single video stream:
9142 [a0][a1][a2]mergeplanes=0x001020:yuv444p
9146 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
9148 [a0][a1]mergeplanes=0x00010210:yuva444p
9152 Swap Y and A plane in yuva444p stream:
9154 format=yuva444p,mergeplanes=0x03010200:yuva444p
9158 Swap U and V plane in yuv420p stream:
9160 format=yuv420p,mergeplanes=0x000201:yuv420p
9164 Cast a rgb24 clip to yuv444p:
9166 format=rgb24,mergeplanes=0x000102:yuv444p
9170 @section metadata, ametadata
9172 Manipulate frame metadata.
9174 This filter accepts the following options:
9178 Set mode of operation of the filter.
9180 Can be one of the following:
9184 If both @code{value} and @code{key} is set, select frames
9185 which have such metadata. If only @code{key} is set, select
9186 every frame that has such key in metadata.
9189 Add new metadata @code{key} and @code{value}. If key is already available
9193 Modify value of already present key.
9196 If @code{value} is set, delete only keys that have such value.
9197 Otherwise, delete key.
9200 Print key and its value if metadata was found. If @code{key} is not set print all
9201 metadata values available in frame.
9205 Set key used with all modes. Must be set for all modes except @code{print}.
9208 Set metadata value which will be used. This option is mandatory for
9209 @code{modify} and @code{add} mode.
9212 Which function to use when comparing metadata value and @code{value}.
9214 Can be one of following:
9218 Values are interpreted as strings, returns true if metadata value is same as @code{value}.
9221 Values are interpreted as strings, returns true if metadata value starts with
9222 the @code{value} option string.
9225 Values are interpreted as floats, returns true if metadata value is less than @code{value}.
9228 Values are interpreted as floats, returns true if @code{value} is equal with metadata value.
9231 Values are interpreted as floats, returns true if metadata value is greater than @code{value}.
9234 Values are interpreted as floats, returns true if expression from option @code{expr}
9239 Set expression which is used when @code{function} is set to @code{expr}.
9240 The expression is evaluated through the eval API and can contain the following
9245 Float representation of @code{value} from metadata key.
9248 Float representation of @code{value} as supplied by user in @code{value} option.
9252 If specified in @code{print} mode, output is written to the named file. When
9253 filename equals "-" data is written to standard output.
9254 If @code{file} option is not set, output is written to the log with AV_LOG_INFO
9258 @subsection Examples
9262 Print all metadata values for frames with key @code{lavfi.singnalstats.YDIF} with values
9266 signalstats,metadata=print:key=lavfi.signalstats.YDIF:value=0:function=expr:expr='between(VALUE1,0,1)'
9271 Drop frames that do not differ greatly from the previous frame in
9272 order to reduce frame rate.
9274 The main use of this filter is for very-low-bitrate encoding
9275 (e.g. streaming over dialup modem), but it could in theory be used for
9276 fixing movies that were inverse-telecined incorrectly.
9278 A description of the accepted options follows.
9282 Set the maximum number of consecutive frames which can be dropped (if
9283 positive), or the minimum interval between dropped frames (if
9284 negative). If the value is 0, the frame is dropped unregarding the
9285 number of previous sequentially dropped frames.
9292 Set the dropping threshold values.
9294 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
9295 represent actual pixel value differences, so a threshold of 64
9296 corresponds to 1 unit of difference for each pixel, or the same spread
9297 out differently over the block.
9299 A frame is a candidate for dropping if no 8x8 blocks differ by more
9300 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
9301 meaning the whole image) differ by more than a threshold of @option{lo}.
9303 Default value for @option{hi} is 64*12, default value for @option{lo} is
9304 64*5, and default value for @option{frac} is 0.33.
9312 It accepts an integer in input; if non-zero it negates the
9313 alpha component (if available). The default value in input is 0.
9317 Deinterlace video using neural network edge directed interpolation.
9319 This filter accepts the following options:
9323 Mandatory option, without binary file filter can not work.
9324 Currently file can be found here:
9325 https://github.com/dubhater/vapoursynth-nnedi3/blob/master/src/nnedi3_weights.bin
9328 Set which frames to deinterlace, by default it is @code{all}.
9329 Can be @code{all} or @code{interlaced}.
9332 Set mode of operation.
9334 Can be one of the following:
9338 Use frame flags, both fields.
9340 Use frame flags, single field.
9344 Use bottom field only.
9346 Use both fields, top first.
9348 Use both fields, bottom first.
9352 Set which planes to process, by default filter process all frames.
9355 Set size of local neighborhood around each pixel, used by the predictor neural
9358 Can be one of the following:
9371 Set the number of neurons in predicctor neural network.
9372 Can be one of the following:
9383 Controls the number of different neural network predictions that are blended
9384 together to compute the final output value. Can be @code{fast}, default or
9388 Set which set of weights to use in the predictor.
9389 Can be one of the following:
9393 weights trained to minimize absolute error
9395 weights trained to minimize squared error
9399 Controls whether or not the prescreener neural network is used to decide
9400 which pixels should be processed by the predictor neural network and which
9401 can be handled by simple cubic interpolation.
9402 The prescreener is trained to know whether cubic interpolation will be
9403 sufficient for a pixel or whether it should be predicted by the predictor nn.
9404 The computational complexity of the prescreener nn is much less than that of
9405 the predictor nn. Since most pixels can be handled by cubic interpolation,
9406 using the prescreener generally results in much faster processing.
9407 The prescreener is pretty accurate, so the difference between using it and not
9408 using it is almost always unnoticeable.
9410 Can be one of the following:
9418 Default is @code{new}.
9421 Set various debugging flags.
9426 Force libavfilter not to use any of the specified pixel formats for the
9427 input to the next filter.
9429 It accepts the following parameters:
9433 A '|'-separated list of pixel format names, such as
9434 apix_fmts=yuv420p|monow|rgb24".
9438 @subsection Examples
9442 Force libavfilter to use a format different from @var{yuv420p} for the
9443 input to the vflip filter:
9445 noformat=pix_fmts=yuv420p,vflip
9449 Convert the input video to any of the formats not contained in the list:
9451 noformat=yuv420p|yuv444p|yuv410p
9457 Add noise on video input frame.
9459 The filter accepts the following options:
9467 Set noise seed for specific pixel component or all pixel components in case
9468 of @var{all_seed}. Default value is @code{123457}.
9470 @item all_strength, alls
9471 @item c0_strength, c0s
9472 @item c1_strength, c1s
9473 @item c2_strength, c2s
9474 @item c3_strength, c3s
9475 Set noise strength for specific pixel component or all pixel components in case
9476 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
9478 @item all_flags, allf
9483 Set pixel component flags or set flags for all components if @var{all_flags}.
9484 Available values for component flags are:
9487 averaged temporal noise (smoother)
9489 mix random noise with a (semi)regular pattern
9491 temporal noise (noise pattern changes between frames)
9493 uniform noise (gaussian otherwise)
9497 @subsection Examples
9499 Add temporal and uniform noise to input video:
9501 noise=alls=20:allf=t+u
9506 Pass the video source unchanged to the output.
9509 Optical Character Recognition
9511 This filter uses Tesseract for optical character recognition.
9513 It accepts the following options:
9517 Set datapath to tesseract data. Default is to use whatever was
9518 set at installation.
9521 Set language, default is "eng".
9524 Set character whitelist.
9527 Set character blacklist.
9530 The filter exports recognized text as the frame metadata @code{lavfi.ocr.text}.
9534 Apply a video transform using libopencv.
9536 To enable this filter, install the libopencv library and headers and
9537 configure FFmpeg with @code{--enable-libopencv}.
9539 It accepts the following parameters:
9544 The name of the libopencv filter to apply.
9547 The parameters to pass to the libopencv filter. If not specified, the default
9552 Refer to the official libopencv documentation for more precise
9554 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
9556 Several libopencv filters are supported; see the following subsections.
9561 Dilate an image by using a specific structuring element.
9562 It corresponds to the libopencv function @code{cvDilate}.
9564 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
9566 @var{struct_el} represents a structuring element, and has the syntax:
9567 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
9569 @var{cols} and @var{rows} represent the number of columns and rows of
9570 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
9571 point, and @var{shape} the shape for the structuring element. @var{shape}
9572 must be "rect", "cross", "ellipse", or "custom".
9574 If the value for @var{shape} is "custom", it must be followed by a
9575 string of the form "=@var{filename}". The file with name
9576 @var{filename} is assumed to represent a binary image, with each
9577 printable character corresponding to a bright pixel. When a custom
9578 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
9579 or columns and rows of the read file are assumed instead.
9581 The default value for @var{struct_el} is "3x3+0x0/rect".
9583 @var{nb_iterations} specifies the number of times the transform is
9584 applied to the image, and defaults to 1.
9588 # Use the default values
9591 # Dilate using a structuring element with a 5x5 cross, iterating two times
9592 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
9594 # Read the shape from the file diamond.shape, iterating two times.
9595 # The file diamond.shape may contain a pattern of characters like this
9601 # The specified columns and rows are ignored
9602 # but the anchor point coordinates are not
9603 ocv=dilate:0x0+2x2/custom=diamond.shape|2
9608 Erode an image by using a specific structuring element.
9609 It corresponds to the libopencv function @code{cvErode}.
9611 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
9612 with the same syntax and semantics as the @ref{dilate} filter.
9616 Smooth the input video.
9618 The filter takes the following parameters:
9619 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
9621 @var{type} is the type of smooth filter to apply, and must be one of
9622 the following values: "blur", "blur_no_scale", "median", "gaussian",
9623 or "bilateral". The default value is "gaussian".
9625 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
9626 depend on the smooth type. @var{param1} and
9627 @var{param2} accept integer positive values or 0. @var{param3} and
9628 @var{param4} accept floating point values.
9630 The default value for @var{param1} is 3. The default value for the
9631 other parameters is 0.
9633 These parameters correspond to the parameters assigned to the
9634 libopencv function @code{cvSmooth}.
9639 Overlay one video on top of another.
9641 It takes two inputs and has one output. The first input is the "main"
9642 video on which the second input is overlaid.
9644 It accepts the following parameters:
9646 A description of the accepted options follows.
9651 Set the expression for the x and y coordinates of the overlaid video
9652 on the main video. Default value is "0" for both expressions. In case
9653 the expression is invalid, it is set to a huge value (meaning that the
9654 overlay will not be displayed within the output visible area).
9657 The action to take when EOF is encountered on the secondary input; it accepts
9658 one of the following values:
9662 Repeat the last frame (the default).
9666 Pass the main input through.
9670 Set when the expressions for @option{x}, and @option{y} are evaluated.
9672 It accepts the following values:
9675 only evaluate expressions once during the filter initialization or
9676 when a command is processed
9679 evaluate expressions for each incoming frame
9682 Default value is @samp{frame}.
9685 If set to 1, force the output to terminate when the shortest input
9686 terminates. Default value is 0.
9689 Set the format for the output video.
9691 It accepts the following values:
9706 Default value is @samp{yuv420}.
9708 @item rgb @emph{(deprecated)}
9709 If set to 1, force the filter to accept inputs in the RGB
9710 color space. Default value is 0. This option is deprecated, use
9711 @option{format} instead.
9714 If set to 1, force the filter to draw the last overlay frame over the
9715 main input until the end of the stream. A value of 0 disables this
9716 behavior. Default value is 1.
9719 The @option{x}, and @option{y} expressions can contain the following
9725 The main input width and height.
9729 The overlay input width and height.
9733 The computed values for @var{x} and @var{y}. They are evaluated for
9738 horizontal and vertical chroma subsample values of the output
9739 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
9743 the number of input frame, starting from 0
9746 the position in the file of the input frame, NAN if unknown
9749 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
9753 Note that the @var{n}, @var{pos}, @var{t} variables are available only
9754 when evaluation is done @emph{per frame}, and will evaluate to NAN
9755 when @option{eval} is set to @samp{init}.
9757 Be aware that frames are taken from each input video in timestamp
9758 order, hence, if their initial timestamps differ, it is a good idea
9759 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
9760 have them begin in the same zero timestamp, as the example for
9761 the @var{movie} filter does.
9763 You can chain together more overlays but you should test the
9764 efficiency of such approach.
9766 @subsection Commands
9768 This filter supports the following commands:
9772 Modify the x and y of the overlay input.
9773 The command accepts the same syntax of the corresponding option.
9775 If the specified expression is not valid, it is kept at its current
9779 @subsection Examples
9783 Draw the overlay at 10 pixels from the bottom right corner of the main
9786 overlay=main_w-overlay_w-10:main_h-overlay_h-10
9789 Using named options the example above becomes:
9791 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
9795 Insert a transparent PNG logo in the bottom left corner of the input,
9796 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
9798 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
9802 Insert 2 different transparent PNG logos (second logo on bottom
9803 right corner) using the @command{ffmpeg} tool:
9805 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
9809 Add a transparent color layer on top of the main video; @code{WxH}
9810 must specify the size of the main input to the overlay filter:
9812 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
9816 Play an original video and a filtered version (here with the deshake
9817 filter) side by side using the @command{ffplay} tool:
9819 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
9822 The above command is the same as:
9824 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
9828 Make a sliding overlay appearing from the left to the right top part of the
9829 screen starting since time 2:
9831 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
9835 Compose output by putting two input videos side to side:
9837 ffmpeg -i left.avi -i right.avi -filter_complex "
9838 nullsrc=size=200x100 [background];
9839 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
9840 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
9841 [background][left] overlay=shortest=1 [background+left];
9842 [background+left][right] overlay=shortest=1:x=100 [left+right]
9847 Mask 10-20 seconds of a video by applying the delogo filter to a section
9849 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
9850 -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]'
9855 Chain several overlays in cascade:
9857 nullsrc=s=200x200 [bg];
9858 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
9859 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
9860 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
9861 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
9862 [in3] null, [mid2] overlay=100:100 [out0]
9869 Apply Overcomplete Wavelet denoiser.
9871 The filter accepts the following options:
9877 Larger depth values will denoise lower frequency components more, but
9878 slow down filtering.
9880 Must be an int in the range 8-16, default is @code{8}.
9882 @item luma_strength, ls
9885 Must be a double value in the range 0-1000, default is @code{1.0}.
9887 @item chroma_strength, cs
9888 Set chroma strength.
9890 Must be a double value in the range 0-1000, default is @code{1.0}.
9896 Add paddings to the input image, and place the original input at the
9897 provided @var{x}, @var{y} coordinates.
9899 It accepts the following parameters:
9904 Specify an expression for the size of the output image with the
9905 paddings added. If the value for @var{width} or @var{height} is 0, the
9906 corresponding input size is used for the output.
9908 The @var{width} expression can reference the value set by the
9909 @var{height} expression, and vice versa.
9911 The default value of @var{width} and @var{height} is 0.
9915 Specify the offsets to place the input image at within the padded area,
9916 with respect to the top/left border of the output image.
9918 The @var{x} expression can reference the value set by the @var{y}
9919 expression, and vice versa.
9921 The default value of @var{x} and @var{y} is 0.
9924 Specify the color of the padded area. For the syntax of this option,
9925 check the "Color" section in the ffmpeg-utils manual.
9927 The default value of @var{color} is "black".
9930 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
9931 options are expressions containing the following constants:
9936 The input video width and height.
9940 These are the same as @var{in_w} and @var{in_h}.
9944 The output width and height (the size of the padded area), as
9945 specified by the @var{width} and @var{height} expressions.
9949 These are the same as @var{out_w} and @var{out_h}.
9953 The x and y offsets as specified by the @var{x} and @var{y}
9954 expressions, or NAN if not yet specified.
9957 same as @var{iw} / @var{ih}
9960 input sample aspect ratio
9963 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
9967 The horizontal and vertical chroma subsample values. For example for the
9968 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9971 @subsection Examples
9975 Add paddings with the color "violet" to the input video. The output video
9976 size is 640x480, and the top-left corner of the input video is placed at
9979 pad=640:480:0:40:violet
9982 The example above is equivalent to the following command:
9984 pad=width=640:height=480:x=0:y=40:color=violet
9988 Pad the input to get an output with dimensions increased by 3/2,
9989 and put the input video at the center of the padded area:
9991 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
9995 Pad the input to get a squared output with size equal to the maximum
9996 value between the input width and height, and put the input video at
9997 the center of the padded area:
9999 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
10003 Pad the input to get a final w/h ratio of 16:9:
10005 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
10009 In case of anamorphic video, in order to set the output display aspect
10010 correctly, it is necessary to use @var{sar} in the expression,
10011 according to the relation:
10013 (ih * X / ih) * sar = output_dar
10014 X = output_dar / sar
10017 Thus the previous example needs to be modified to:
10019 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
10023 Double the output size and put the input video in the bottom-right
10024 corner of the output padded area:
10026 pad="2*iw:2*ih:ow-iw:oh-ih"
10030 @anchor{palettegen}
10031 @section palettegen
10033 Generate one palette for a whole video stream.
10035 It accepts the following options:
10039 Set the maximum number of colors to quantize in the palette.
10040 Note: the palette will still contain 256 colors; the unused palette entries
10043 @item reserve_transparent
10044 Create a palette of 255 colors maximum and reserve the last one for
10045 transparency. Reserving the transparency color is useful for GIF optimization.
10046 If not set, the maximum of colors in the palette will be 256. You probably want
10047 to disable this option for a standalone image.
10051 Set statistics mode.
10053 It accepts the following values:
10056 Compute full frame histograms.
10058 Compute histograms only for the part that differs from previous frame. This
10059 might be relevant to give more importance to the moving part of your input if
10060 the background is static.
10063 Default value is @var{full}.
10066 The filter also exports the frame metadata @code{lavfi.color_quant_ratio}
10067 (@code{nb_color_in / nb_color_out}) which you can use to evaluate the degree of
10068 color quantization of the palette. This information is also visible at
10069 @var{info} logging level.
10071 @subsection Examples
10075 Generate a representative palette of a given video using @command{ffmpeg}:
10077 ffmpeg -i input.mkv -vf palettegen palette.png
10081 @section paletteuse
10083 Use a palette to downsample an input video stream.
10085 The filter takes two inputs: one video stream and a palette. The palette must
10086 be a 256 pixels image.
10088 It accepts the following options:
10092 Select dithering mode. Available algorithms are:
10095 Ordered 8x8 bayer dithering (deterministic)
10097 Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
10098 Note: this dithering is sometimes considered "wrong" and is included as a
10100 @item floyd_steinberg
10101 Floyd and Steingberg dithering (error diffusion)
10103 Frankie Sierra dithering v2 (error diffusion)
10105 Frankie Sierra dithering v2 "Lite" (error diffusion)
10108 Default is @var{sierra2_4a}.
10111 When @var{bayer} dithering is selected, this option defines the scale of the
10112 pattern (how much the crosshatch pattern is visible). A low value means more
10113 visible pattern for less banding, and higher value means less visible pattern
10114 at the cost of more banding.
10116 The option must be an integer value in the range [0,5]. Default is @var{2}.
10119 If set, define the zone to process
10123 Only the changing rectangle will be reprocessed. This is similar to GIF
10124 cropping/offsetting compression mechanism. This option can be useful for speed
10125 if only a part of the image is changing, and has use cases such as limiting the
10126 scope of the error diffusal @option{dither} to the rectangle that bounds the
10127 moving scene (it leads to more deterministic output if the scene doesn't change
10128 much, and as a result less moving noise and better GIF compression).
10131 Default is @var{none}.
10134 @subsection Examples
10138 Use a palette (generated for example with @ref{palettegen}) to encode a GIF
10139 using @command{ffmpeg}:
10141 ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
10145 @section perspective
10147 Correct perspective of video not recorded perpendicular to the screen.
10149 A description of the accepted parameters follows.
10160 Set coordinates expression for top left, top right, bottom left and bottom right corners.
10161 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
10162 If the @code{sense} option is set to @code{source}, then the specified points will be sent
10163 to the corners of the destination. If the @code{sense} option is set to @code{destination},
10164 then the corners of the source will be sent to the specified coordinates.
10166 The expressions can use the following variables:
10171 the width and height of video frame.
10175 Output frame count.
10178 @item interpolation
10179 Set interpolation for perspective correction.
10181 It accepts the following values:
10187 Default value is @samp{linear}.
10190 Set interpretation of coordinate options.
10192 It accepts the following values:
10196 Send point in the source specified by the given coordinates to
10197 the corners of the destination.
10199 @item 1, destination
10201 Send the corners of the source to the point in the destination specified
10202 by the given coordinates.
10204 Default value is @samp{source}.
10208 Set when the expressions for coordinates @option{x0,y0,...x3,y3} are evaluated.
10210 It accepts the following values:
10213 only evaluate expressions once during the filter initialization or
10214 when a command is processed
10217 evaluate expressions for each incoming frame
10220 Default value is @samp{init}.
10225 Delay interlaced video by one field time so that the field order changes.
10227 The intended use is to fix PAL movies that have been captured with the
10228 opposite field order to the film-to-video transfer.
10230 A description of the accepted parameters follows.
10236 It accepts the following values:
10239 Capture field order top-first, transfer bottom-first.
10240 Filter will delay the bottom field.
10243 Capture field order bottom-first, transfer top-first.
10244 Filter will delay the top field.
10247 Capture and transfer with the same field order. This mode only exists
10248 for the documentation of the other options to refer to, but if you
10249 actually select it, the filter will faithfully do nothing.
10252 Capture field order determined automatically by field flags, transfer
10254 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
10255 basis using field flags. If no field information is available,
10256 then this works just like @samp{u}.
10259 Capture unknown or varying, transfer opposite.
10260 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
10261 analyzing the images and selecting the alternative that produces best
10262 match between the fields.
10265 Capture top-first, transfer unknown or varying.
10266 Filter selects among @samp{t} and @samp{p} using image analysis.
10269 Capture bottom-first, transfer unknown or varying.
10270 Filter selects among @samp{b} and @samp{p} using image analysis.
10273 Capture determined by field flags, transfer unknown or varying.
10274 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
10275 image analysis. If no field information is available, then this works just
10276 like @samp{U}. This is the default mode.
10279 Both capture and transfer unknown or varying.
10280 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
10284 @section pixdesctest
10286 Pixel format descriptor test filter, mainly useful for internal
10287 testing. The output video should be equal to the input video.
10291 format=monow, pixdesctest
10294 can be used to test the monowhite pixel format descriptor definition.
10298 Enable the specified chain of postprocessing subfilters using libpostproc. This
10299 library should be automatically selected with a GPL build (@code{--enable-gpl}).
10300 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
10301 Each subfilter and some options have a short and a long name that can be used
10302 interchangeably, i.e. dr/dering are the same.
10304 The filters accept the following options:
10308 Set postprocessing subfilters string.
10311 All subfilters share common options to determine their scope:
10315 Honor the quality commands for this subfilter.
10318 Do chrominance filtering, too (default).
10321 Do luminance filtering only (no chrominance).
10324 Do chrominance filtering only (no luminance).
10327 These options can be appended after the subfilter name, separated by a '|'.
10329 Available subfilters are:
10332 @item hb/hdeblock[|difference[|flatness]]
10333 Horizontal deblocking filter
10336 Difference factor where higher values mean more deblocking (default: @code{32}).
10338 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10341 @item vb/vdeblock[|difference[|flatness]]
10342 Vertical deblocking filter
10345 Difference factor where higher values mean more deblocking (default: @code{32}).
10347 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10350 @item ha/hadeblock[|difference[|flatness]]
10351 Accurate horizontal deblocking filter
10354 Difference factor where higher values mean more deblocking (default: @code{32}).
10356 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10359 @item va/vadeblock[|difference[|flatness]]
10360 Accurate vertical deblocking filter
10363 Difference factor where higher values mean more deblocking (default: @code{32}).
10365 Flatness threshold where lower values mean more deblocking (default: @code{39}).
10369 The horizontal and vertical deblocking filters share the difference and
10370 flatness values so you cannot set different horizontal and vertical
10374 @item h1/x1hdeblock
10375 Experimental horizontal deblocking filter
10377 @item v1/x1vdeblock
10378 Experimental vertical deblocking filter
10383 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
10386 larger -> stronger filtering
10388 larger -> stronger filtering
10390 larger -> stronger filtering
10393 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
10396 Stretch luminance to @code{0-255}.
10399 @item lb/linblenddeint
10400 Linear blend deinterlacing filter that deinterlaces the given block by
10401 filtering all lines with a @code{(1 2 1)} filter.
10403 @item li/linipoldeint
10404 Linear interpolating deinterlacing filter that deinterlaces the given block by
10405 linearly interpolating every second line.
10407 @item ci/cubicipoldeint
10408 Cubic interpolating deinterlacing filter deinterlaces the given block by
10409 cubically interpolating every second line.
10411 @item md/mediandeint
10412 Median deinterlacing filter that deinterlaces the given block by applying a
10413 median filter to every second line.
10415 @item fd/ffmpegdeint
10416 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
10417 second line with a @code{(-1 4 2 4 -1)} filter.
10420 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
10421 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
10423 @item fq/forceQuant[|quantizer]
10424 Overrides the quantizer table from the input with the constant quantizer you
10432 Default pp filter combination (@code{hb|a,vb|a,dr|a})
10435 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
10438 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
10441 @subsection Examples
10445 Apply horizontal and vertical deblocking, deringing and automatic
10446 brightness/contrast:
10452 Apply default filters without brightness/contrast correction:
10458 Apply default filters and temporal denoiser:
10460 pp=default/tmpnoise|1|2|3
10464 Apply deblocking on luminance only, and switch vertical deblocking on or off
10465 automatically depending on available CPU time:
10472 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
10473 similar to spp = 6 with 7 point DCT, where only the center sample is
10476 The filter accepts the following options:
10480 Force a constant quantization parameter. It accepts an integer in range
10481 0 to 63. If not set, the filter will use the QP from the video stream
10485 Set thresholding mode. Available modes are:
10489 Set hard thresholding.
10491 Set soft thresholding (better de-ringing effect, but likely blurrier).
10493 Set medium thresholding (good results, default).
10499 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
10500 Ratio) between two input videos.
10502 This filter takes in input two input videos, the first input is
10503 considered the "main" source and is passed unchanged to the
10504 output. The second input is used as a "reference" video for computing
10507 Both video inputs must have the same resolution and pixel format for
10508 this filter to work correctly. Also it assumes that both inputs
10509 have the same number of frames, which are compared one by one.
10511 The obtained average PSNR is printed through the logging system.
10513 The filter stores the accumulated MSE (mean squared error) of each
10514 frame, and at the end of the processing it is averaged across all frames
10515 equally, and the following formula is applied to obtain the PSNR:
10518 PSNR = 10*log10(MAX^2/MSE)
10521 Where MAX is the average of the maximum values of each component of the
10524 The description of the accepted parameters follows.
10527 @item stats_file, f
10528 If specified the filter will use the named file to save the PSNR of
10529 each individual frame. When filename equals "-" the data is sent to
10533 The file printed if @var{stats_file} is selected, contains a sequence of
10534 key/value pairs of the form @var{key}:@var{value} for each compared
10537 A description of each shown parameter follows:
10541 sequential number of the input frame, starting from 1
10544 Mean Square Error pixel-by-pixel average difference of the compared
10545 frames, averaged over all the image components.
10547 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
10548 Mean Square Error pixel-by-pixel average difference of the compared
10549 frames for the component specified by the suffix.
10551 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
10552 Peak Signal to Noise ratio of the compared frames for the component
10553 specified by the suffix.
10558 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
10559 [main][ref] psnr="stats_file=stats.log" [out]
10562 On this example the input file being processed is compared with the
10563 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
10564 is stored in @file{stats.log}.
10569 Pulldown reversal (inverse telecine) filter, capable of handling mixed
10570 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
10573 The pullup filter is designed to take advantage of future context in making
10574 its decisions. This filter is stateless in the sense that it does not lock
10575 onto a pattern to follow, but it instead looks forward to the following
10576 fields in order to identify matches and rebuild progressive frames.
10578 To produce content with an even framerate, insert the fps filter after
10579 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
10580 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
10582 The filter accepts the following options:
10589 These options set the amount of "junk" to ignore at the left, right, top, and
10590 bottom of the image, respectively. Left and right are in units of 8 pixels,
10591 while top and bottom are in units of 2 lines.
10592 The default is 8 pixels on each side.
10595 Set the strict breaks. Setting this option to 1 will reduce the chances of
10596 filter generating an occasional mismatched frame, but it may also cause an
10597 excessive number of frames to be dropped during high motion sequences.
10598 Conversely, setting it to -1 will make filter match fields more easily.
10599 This may help processing of video where there is slight blurring between
10600 the fields, but may also cause there to be interlaced frames in the output.
10601 Default value is @code{0}.
10604 Set the metric plane to use. It accepts the following values:
10610 Use chroma blue plane.
10613 Use chroma red plane.
10616 This option may be set to use chroma plane instead of the default luma plane
10617 for doing filter's computations. This may improve accuracy on very clean
10618 source material, but more likely will decrease accuracy, especially if there
10619 is chroma noise (rainbow effect) or any grayscale video.
10620 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
10621 load and make pullup usable in realtime on slow machines.
10624 For best results (without duplicated frames in the output file) it is
10625 necessary to change the output frame rate. For example, to inverse
10626 telecine NTSC input:
10628 ffmpeg -i input -vf pullup -r 24000/1001 ...
10633 Change video quantization parameters (QP).
10635 The filter accepts the following option:
10639 Set expression for quantization parameter.
10642 The expression is evaluated through the eval API and can contain, among others,
10643 the following constants:
10647 1 if index is not 129, 0 otherwise.
10650 Sequentional index starting from -129 to 128.
10653 @subsection Examples
10657 Some equation like:
10665 Flush video frames from internal cache of frames into a random order.
10666 No frame is discarded.
10667 Inspired by @ref{frei0r} nervous filter.
10671 Set size in number of frames of internal cache, in range from @code{2} to
10672 @code{512}. Default is @code{30}.
10675 Set seed for random number generator, must be an integer included between
10676 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
10677 less than @code{0}, the filter will try to use a good random seed on a
10683 Read vertical interval timecode (VITC) information from the top lines of a
10686 The filter adds frame metadata key @code{lavfi.readvitc.tc_str} with the
10687 timecode value, if a valid timecode has been detected. Further metadata key
10688 @code{lavfi.readvitc.found} is set to 0/1 depending on whether
10689 timecode data has been found or not.
10691 This filter accepts the following options:
10695 Set the maximum number of lines to scan for VITC data. If the value is set to
10696 @code{-1} the full video frame is scanned. Default is @code{45}.
10699 Set the luma threshold for black. Accepts float numbers in the range [0.0,1.0],
10700 default value is @code{0.2}. The value must be equal or less than @code{thr_w}.
10703 Set the luma threshold for white. Accepts float numbers in the range [0.0,1.0],
10704 default value is @code{0.6}. The value must be equal or greater than @code{thr_b}.
10707 @subsection Examples
10711 Detect and draw VITC data onto the video frame; if no valid VITC is detected,
10712 draw @code{--:--:--:--} as a placeholder:
10714 ffmpeg -i input.avi -filter:v 'readvitc,drawtext=fontfile=FreeMono.ttf:text=%@{metadata\\:lavfi.readvitc.tc_str\\:--\\\\\\:--\\\\\\:--\\\\\\:--@}:x=(w-tw)/2:y=400-ascent'
10720 Remap pixels using 2nd: Xmap and 3rd: Ymap input video stream.
10722 Destination pixel at position (X, Y) will be picked from source (x, y) position
10723 where x = Xmap(X, Y) and y = Ymap(X, Y). If mapping values are out of range, zero
10724 value for pixel will be used for destination pixel.
10726 Xmap and Ymap input video streams must be of same dimensions. Output video stream
10727 will have Xmap/Ymap video stream dimensions.
10728 Xmap and Ymap input video streams are 16bit depth, single channel.
10730 @section removegrain
10732 The removegrain filter is a spatial denoiser for progressive video.
10736 Set mode for the first plane.
10739 Set mode for the second plane.
10742 Set mode for the third plane.
10745 Set mode for the fourth plane.
10748 Range of mode is from 0 to 24. Description of each mode follows:
10752 Leave input plane unchanged. Default.
10755 Clips the pixel with the minimum and maximum of the 8 neighbour pixels.
10758 Clips the pixel with the second minimum and maximum of the 8 neighbour pixels.
10761 Clips the pixel with the third minimum and maximum of the 8 neighbour pixels.
10764 Clips the pixel with the fourth minimum and maximum of the 8 neighbour pixels.
10765 This is equivalent to a median filter.
10768 Line-sensitive clipping giving the minimal change.
10771 Line-sensitive clipping, intermediate.
10774 Line-sensitive clipping, intermediate.
10777 Line-sensitive clipping, intermediate.
10780 Line-sensitive clipping on a line where the neighbours pixels are the closest.
10783 Replaces the target pixel with the closest neighbour.
10786 [1 2 1] horizontal and vertical kernel blur.
10792 Bob mode, interpolates top field from the line where the neighbours
10793 pixels are the closest.
10796 Bob mode, interpolates bottom field from the line where the neighbours
10797 pixels are the closest.
10800 Bob mode, interpolates top field. Same as 13 but with a more complicated
10801 interpolation formula.
10804 Bob mode, interpolates bottom field. Same as 14 but with a more complicated
10805 interpolation formula.
10808 Clips the pixel with the minimum and maximum of respectively the maximum and
10809 minimum of each pair of opposite neighbour pixels.
10812 Line-sensitive clipping using opposite neighbours whose greatest distance from
10813 the current pixel is minimal.
10816 Replaces the pixel with the average of its 8 neighbours.
10819 Averages the 9 pixels ([1 1 1] horizontal and vertical blur).
10822 Clips pixels using the averages of opposite neighbour.
10825 Same as mode 21 but simpler and faster.
10828 Small edge and halo removal, but reputed useless.
10834 @section removelogo
10836 Suppress a TV station logo, using an image file to determine which
10837 pixels comprise the logo. It works by filling in the pixels that
10838 comprise the logo with neighboring pixels.
10840 The filter accepts the following options:
10844 Set the filter bitmap file, which can be any image format supported by
10845 libavformat. The width and height of the image file must match those of the
10846 video stream being processed.
10849 Pixels in the provided bitmap image with a value of zero are not
10850 considered part of the logo, non-zero pixels are considered part of
10851 the logo. If you use white (255) for the logo and black (0) for the
10852 rest, you will be safe. For making the filter bitmap, it is
10853 recommended to take a screen capture of a black frame with the logo
10854 visible, and then using a threshold filter followed by the erode
10855 filter once or twice.
10857 If needed, little splotches can be fixed manually. Remember that if
10858 logo pixels are not covered, the filter quality will be much
10859 reduced. Marking too many pixels as part of the logo does not hurt as
10860 much, but it will increase the amount of blurring needed to cover over
10861 the image and will destroy more information than necessary, and extra
10862 pixels will slow things down on a large logo.
10864 @section repeatfields
10866 This filter uses the repeat_field flag from the Video ES headers and hard repeats
10867 fields based on its value.
10869 @section reverse, areverse
10873 Warning: This filter requires memory to buffer the entire clip, so trimming
10876 @subsection Examples
10880 Take the first 5 seconds of a clip, and reverse it.
10888 Rotate video by an arbitrary angle expressed in radians.
10890 The filter accepts the following options:
10892 A description of the optional parameters follows.
10895 Set an expression for the angle by which to rotate the input video
10896 clockwise, expressed as a number of radians. A negative value will
10897 result in a counter-clockwise rotation. By default it is set to "0".
10899 This expression is evaluated for each frame.
10902 Set the output width expression, default value is "iw".
10903 This expression is evaluated just once during configuration.
10906 Set the output height expression, default value is "ih".
10907 This expression is evaluated just once during configuration.
10910 Enable bilinear interpolation if set to 1, a value of 0 disables
10911 it. Default value is 1.
10914 Set the color used to fill the output area not covered by the rotated
10915 image. For the general syntax of this option, check the "Color" section in the
10916 ffmpeg-utils manual. If the special value "none" is selected then no
10917 background is printed (useful for example if the background is never shown).
10919 Default value is "black".
10922 The expressions for the angle and the output size can contain the
10923 following constants and functions:
10927 sequential number of the input frame, starting from 0. It is always NAN
10928 before the first frame is filtered.
10931 time in seconds of the input frame, it is set to 0 when the filter is
10932 configured. It is always NAN before the first frame is filtered.
10936 horizontal and vertical chroma subsample values. For example for the
10937 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
10941 the input video width and height
10945 the output width and height, that is the size of the padded area as
10946 specified by the @var{width} and @var{height} expressions
10950 the minimal width/height required for completely containing the input
10951 video rotated by @var{a} radians.
10953 These are only available when computing the @option{out_w} and
10954 @option{out_h} expressions.
10957 @subsection Examples
10961 Rotate the input by PI/6 radians clockwise:
10967 Rotate the input by PI/6 radians counter-clockwise:
10973 Rotate the input by 45 degrees clockwise:
10979 Apply a constant rotation with period T, starting from an angle of PI/3:
10981 rotate=PI/3+2*PI*t/T
10985 Make the input video rotation oscillating with a period of T
10986 seconds and an amplitude of A radians:
10988 rotate=A*sin(2*PI/T*t)
10992 Rotate the video, output size is chosen so that the whole rotating
10993 input video is always completely contained in the output:
10995 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
10999 Rotate the video, reduce the output size so that no background is ever
11002 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
11006 @subsection Commands
11008 The filter supports the following commands:
11012 Set the angle expression.
11013 The command accepts the same syntax of the corresponding option.
11015 If the specified expression is not valid, it is kept at its current
11021 Apply Shape Adaptive Blur.
11023 The filter accepts the following options:
11026 @item luma_radius, lr
11027 Set luma blur filter strength, must be a value in range 0.1-4.0, default
11028 value is 1.0. A greater value will result in a more blurred image, and
11029 in slower processing.
11031 @item luma_pre_filter_radius, lpfr
11032 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
11035 @item luma_strength, ls
11036 Set luma maximum difference between pixels to still be considered, must
11037 be a value in the 0.1-100.0 range, default value is 1.0.
11039 @item chroma_radius, cr
11040 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
11041 greater value will result in a more blurred image, and in slower
11044 @item chroma_pre_filter_radius, cpfr
11045 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
11047 @item chroma_strength, cs
11048 Set chroma maximum difference between pixels to still be considered,
11049 must be a value in the 0.1-100.0 range.
11052 Each chroma option value, if not explicitly specified, is set to the
11053 corresponding luma option value.
11058 Scale (resize) the input video, using the libswscale library.
11060 The scale filter forces the output display aspect ratio to be the same
11061 of the input, by changing the output sample aspect ratio.
11063 If the input image format is different from the format requested by
11064 the next filter, the scale filter will convert the input to the
11067 @subsection Options
11068 The filter accepts the following options, or any of the options
11069 supported by the libswscale scaler.
11071 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
11072 the complete list of scaler options.
11077 Set the output video dimension expression. Default value is the input
11080 If the value is 0, the input width is used for the output.
11082 If one of the values is -1, the scale filter will use a value that
11083 maintains the aspect ratio of the input image, calculated from the
11084 other specified dimension. If both of them are -1, the input size is
11087 If one of the values is -n with n > 1, the scale filter will also use a value
11088 that maintains the aspect ratio of the input image, calculated from the other
11089 specified dimension. After that it will, however, make sure that the calculated
11090 dimension is divisible by n and adjust the value if necessary.
11092 See below for the list of accepted constants for use in the dimension
11096 Specify when to evaluate @var{width} and @var{height} expression. It accepts the following values:
11100 Only evaluate expressions once during the filter initialization or when a command is processed.
11103 Evaluate expressions for each incoming frame.
11107 Default value is @samp{init}.
11111 Set the interlacing mode. It accepts the following values:
11115 Force interlaced aware scaling.
11118 Do not apply interlaced scaling.
11121 Select interlaced aware scaling depending on whether the source frames
11122 are flagged as interlaced or not.
11125 Default value is @samp{0}.
11128 Set libswscale scaling flags. See
11129 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
11130 complete list of values. If not explicitly specified the filter applies
11134 @item param0, param1
11135 Set libswscale input parameters for scaling algorithms that need them. See
11136 @ref{sws_params,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
11137 complete documentation. If not explicitly specified the filter applies
11143 Set the video size. For the syntax of this option, check the
11144 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11146 @item in_color_matrix
11147 @item out_color_matrix
11148 Set in/output YCbCr color space type.
11150 This allows the autodetected value to be overridden as well as allows forcing
11151 a specific value used for the output and encoder.
11153 If not specified, the color space type depends on the pixel format.
11159 Choose automatically.
11162 Format conforming to International Telecommunication Union (ITU)
11163 Recommendation BT.709.
11166 Set color space conforming to the United States Federal Communications
11167 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
11170 Set color space conforming to:
11174 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
11177 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
11180 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
11185 Set color space conforming to SMPTE ST 240:1999.
11190 Set in/output YCbCr sample range.
11192 This allows the autodetected value to be overridden as well as allows forcing
11193 a specific value used for the output and encoder. If not specified, the
11194 range depends on the pixel format. Possible values:
11198 Choose automatically.
11201 Set full range (0-255 in case of 8-bit luma).
11204 Set "MPEG" range (16-235 in case of 8-bit luma).
11207 @item force_original_aspect_ratio
11208 Enable decreasing or increasing output video width or height if necessary to
11209 keep the original aspect ratio. Possible values:
11213 Scale the video as specified and disable this feature.
11216 The output video dimensions will automatically be decreased if needed.
11219 The output video dimensions will automatically be increased if needed.
11223 One useful instance of this option is that when you know a specific device's
11224 maximum allowed resolution, you can use this to limit the output video to
11225 that, while retaining the aspect ratio. For example, device A allows
11226 1280x720 playback, and your video is 1920x800. Using this option (set it to
11227 decrease) and specifying 1280x720 to the command line makes the output
11230 Please note that this is a different thing than specifying -1 for @option{w}
11231 or @option{h}, you still need to specify the output resolution for this option
11236 The values of the @option{w} and @option{h} options are expressions
11237 containing the following constants:
11242 The input width and height
11246 These are the same as @var{in_w} and @var{in_h}.
11250 The output (scaled) width and height
11254 These are the same as @var{out_w} and @var{out_h}
11257 The same as @var{iw} / @var{ih}
11260 input sample aspect ratio
11263 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
11267 horizontal and vertical input chroma subsample values. For example for the
11268 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11272 horizontal and vertical output chroma subsample values. For example for the
11273 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11276 @subsection Examples
11280 Scale the input video to a size of 200x100
11285 This is equivalent to:
11296 Specify a size abbreviation for the output size:
11301 which can also be written as:
11307 Scale the input to 2x:
11309 scale=w=2*iw:h=2*ih
11313 The above is the same as:
11315 scale=2*in_w:2*in_h
11319 Scale the input to 2x with forced interlaced scaling:
11321 scale=2*iw:2*ih:interl=1
11325 Scale the input to half size:
11327 scale=w=iw/2:h=ih/2
11331 Increase the width, and set the height to the same size:
11337 Seek Greek harmony:
11344 Increase the height, and set the width to 3/2 of the height:
11346 scale=w=3/2*oh:h=3/5*ih
11350 Increase the size, making the size a multiple of the chroma
11353 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
11357 Increase the width to a maximum of 500 pixels,
11358 keeping the same aspect ratio as the input:
11360 scale=w='min(500\, iw*3/2):h=-1'
11364 @subsection Commands
11366 This filter supports the following commands:
11370 Set the output video dimension expression.
11371 The command accepts the same syntax of the corresponding option.
11373 If the specified expression is not valid, it is kept at its current
11379 Scale (resize) the input video, based on a reference video.
11381 See the scale filter for available options, scale2ref supports the same but
11382 uses the reference video instead of the main input as basis.
11384 @subsection Examples
11388 Scale a subtitle stream to match the main video in size before overlaying
11390 'scale2ref[b][a];[a][b]overlay'
11394 @anchor{selectivecolor}
11395 @section selectivecolor
11397 Adjust cyan, magenta, yellow and black (CMYK) to certain ranges of colors (such
11398 as "reds", "yellows", "greens", "cyans", ...). The adjustment range is defined
11399 by the "purity" of the color (that is, how saturated it already is).
11401 This filter is similar to the Adobe Photoshop Selective Color tool.
11403 The filter accepts the following options:
11406 @item correction_method
11407 Select color correction method.
11409 Available values are:
11412 Specified adjustments are applied "as-is" (added/subtracted to original pixel
11415 Specified adjustments are relative to the original component value.
11417 Default is @code{absolute}.
11419 Adjustments for red pixels (pixels where the red component is the maximum)
11421 Adjustments for yellow pixels (pixels where the blue component is the minimum)
11423 Adjustments for green pixels (pixels where the green component is the maximum)
11425 Adjustments for cyan pixels (pixels where the red component is the minimum)
11427 Adjustments for blue pixels (pixels where the blue component is the maximum)
11429 Adjustments for magenta pixels (pixels where the green component is the minimum)
11431 Adjustments for white pixels (pixels where all components are greater than 128)
11433 Adjustments for all pixels except pure black and pure white
11435 Adjustments for black pixels (pixels where all components are lesser than 128)
11437 Specify a Photoshop selective color file (@code{.asv}) to import the settings from.
11440 All the adjustment settings (@option{reds}, @option{yellows}, ...) accept up to
11441 4 space separated floating point adjustment values in the [-1,1] range,
11442 respectively to adjust the amount of cyan, magenta, yellow and black for the
11443 pixels of its range.
11445 @subsection Examples
11449 Increase cyan by 50% and reduce yellow by 33% in every green areas, and
11450 increase magenta by 27% in blue areas:
11452 selectivecolor=greens=.5 0 -.33 0:blues=0 .27
11456 Use a Photoshop selective color preset:
11458 selectivecolor=psfile=MySelectiveColorPresets/Misty.asv
11462 @section separatefields
11464 The @code{separatefields} takes a frame-based video input and splits
11465 each frame into its components fields, producing a new half height clip
11466 with twice the frame rate and twice the frame count.
11468 This filter use field-dominance information in frame to decide which
11469 of each pair of fields to place first in the output.
11470 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
11472 @section setdar, setsar
11474 The @code{setdar} filter sets the Display Aspect Ratio for the filter
11477 This is done by changing the specified Sample (aka Pixel) Aspect
11478 Ratio, according to the following equation:
11480 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
11483 Keep in mind that the @code{setdar} filter does not modify the pixel
11484 dimensions of the video frame. Also, the display aspect ratio set by
11485 this filter may be changed by later filters in the filterchain,
11486 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
11489 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
11490 the filter output video.
11492 Note that as a consequence of the application of this filter, the
11493 output display aspect ratio will change according to the equation
11496 Keep in mind that the sample aspect ratio set by the @code{setsar}
11497 filter may be changed by later filters in the filterchain, e.g. if
11498 another "setsar" or a "setdar" filter is applied.
11500 It accepts the following parameters:
11503 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
11504 Set the aspect ratio used by the filter.
11506 The parameter can be a floating point number string, an expression, or
11507 a string of the form @var{num}:@var{den}, where @var{num} and
11508 @var{den} are the numerator and denominator of the aspect ratio. If
11509 the parameter is not specified, it is assumed the value "0".
11510 In case the form "@var{num}:@var{den}" is used, the @code{:} character
11514 Set the maximum integer value to use for expressing numerator and
11515 denominator when reducing the expressed aspect ratio to a rational.
11516 Default value is @code{100}.
11520 The parameter @var{sar} is an expression containing
11521 the following constants:
11525 These are approximated values for the mathematical constants e
11526 (Euler's number), pi (Greek pi), and phi (the golden ratio).
11529 The input width and height.
11532 These are the same as @var{w} / @var{h}.
11535 The input sample aspect ratio.
11538 The input display aspect ratio. It is the same as
11539 (@var{w} / @var{h}) * @var{sar}.
11542 Horizontal and vertical chroma subsample values. For example, for the
11543 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
11546 @subsection Examples
11551 To change the display aspect ratio to 16:9, specify one of the following:
11559 To change the sample aspect ratio to 10:11, specify:
11565 To set a display aspect ratio of 16:9, and specify a maximum integer value of
11566 1000 in the aspect ratio reduction, use the command:
11568 setdar=ratio=16/9:max=1000
11576 Force field for the output video frame.
11578 The @code{setfield} filter marks the interlace type field for the
11579 output frames. It does not change the input frame, but only sets the
11580 corresponding property, which affects how the frame is treated by
11581 following filters (e.g. @code{fieldorder} or @code{yadif}).
11583 The filter accepts the following options:
11588 Available values are:
11592 Keep the same field property.
11595 Mark the frame as bottom-field-first.
11598 Mark the frame as top-field-first.
11601 Mark the frame as progressive.
11607 Show a line containing various information for each input video frame.
11608 The input video is not modified.
11610 The shown line contains a sequence of key/value pairs of the form
11611 @var{key}:@var{value}.
11613 The following values are shown in the output:
11617 The (sequential) number of the input frame, starting from 0.
11620 The Presentation TimeStamp of the input frame, expressed as a number of
11621 time base units. The time base unit depends on the filter input pad.
11624 The Presentation TimeStamp of the input frame, expressed as a number of
11628 The position of the frame in the input stream, or -1 if this information is
11629 unavailable and/or meaningless (for example in case of synthetic video).
11632 The pixel format name.
11635 The sample aspect ratio of the input frame, expressed in the form
11636 @var{num}/@var{den}.
11639 The size of the input frame. For the syntax of this option, check the
11640 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11643 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
11644 for bottom field first).
11647 This is 1 if the frame is a key frame, 0 otherwise.
11650 The picture type of the input frame ("I" for an I-frame, "P" for a
11651 P-frame, "B" for a B-frame, or "?" for an unknown type).
11652 Also refer to the documentation of the @code{AVPictureType} enum and of
11653 the @code{av_get_picture_type_char} function defined in
11654 @file{libavutil/avutil.h}.
11657 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
11659 @item plane_checksum
11660 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
11661 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
11664 @section showpalette
11666 Displays the 256 colors palette of each frame. This filter is only relevant for
11667 @var{pal8} pixel format frames.
11669 It accepts the following option:
11673 Set the size of the box used to represent one palette color entry. Default is
11674 @code{30} (for a @code{30x30} pixel box).
11677 @section shuffleframes
11679 Reorder and/or duplicate video frames.
11681 It accepts the following parameters:
11685 Set the destination indexes of input frames.
11686 This is space or '|' separated list of indexes that maps input frames to output
11687 frames. Number of indexes also sets maximal value that each index may have.
11690 The first frame has the index 0. The default is to keep the input unchanged.
11692 Swap second and third frame of every three frames of the input:
11694 ffmpeg -i INPUT -vf "shuffleframes=0 2 1" OUTPUT
11697 @section shuffleplanes
11699 Reorder and/or duplicate video planes.
11701 It accepts the following parameters:
11706 The index of the input plane to be used as the first output plane.
11709 The index of the input plane to be used as the second output plane.
11712 The index of the input plane to be used as the third output plane.
11715 The index of the input plane to be used as the fourth output plane.
11719 The first plane has the index 0. The default is to keep the input unchanged.
11721 Swap the second and third planes of the input:
11723 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
11726 @anchor{signalstats}
11727 @section signalstats
11728 Evaluate various visual metrics that assist in determining issues associated
11729 with the digitization of analog video media.
11731 By default the filter will log these metadata values:
11735 Display the minimal Y value contained within the input frame. Expressed in
11739 Display the Y value at the 10% percentile within the input frame. Expressed in
11743 Display the average Y value within the input frame. Expressed in range of
11747 Display the Y value at the 90% percentile within the input frame. Expressed in
11751 Display the maximum Y value contained within the input frame. Expressed in
11755 Display the minimal U value contained within the input frame. Expressed in
11759 Display the U value at the 10% percentile within the input frame. Expressed in
11763 Display the average U value within the input frame. Expressed in range of
11767 Display the U value at the 90% percentile within the input frame. Expressed in
11771 Display the maximum U value contained within the input frame. Expressed in
11775 Display the minimal V value contained within the input frame. Expressed in
11779 Display the V value at the 10% percentile within the input frame. Expressed in
11783 Display the average V value within the input frame. Expressed in range of
11787 Display the V value at the 90% percentile within the input frame. Expressed in
11791 Display the maximum V value contained within the input frame. Expressed in
11795 Display the minimal saturation value contained within the input frame.
11796 Expressed in range of [0-~181.02].
11799 Display the saturation value at the 10% percentile within the input frame.
11800 Expressed in range of [0-~181.02].
11803 Display the average saturation value within the input frame. Expressed in range
11807 Display the saturation value at the 90% percentile within the input frame.
11808 Expressed in range of [0-~181.02].
11811 Display the maximum saturation value contained within the input frame.
11812 Expressed in range of [0-~181.02].
11815 Display the median value for hue within the input frame. Expressed in range of
11819 Display the average value for hue within the input frame. Expressed in range of
11823 Display the average of sample value difference between all values of the Y
11824 plane in the current frame and corresponding values of the previous input frame.
11825 Expressed in range of [0-255].
11828 Display the average of sample value difference between all values of the U
11829 plane in the current frame and corresponding values of the previous input frame.
11830 Expressed in range of [0-255].
11833 Display the average of sample value difference between all values of the V
11834 plane in the current frame and corresponding values of the previous input frame.
11835 Expressed in range of [0-255].
11838 The filter accepts the following options:
11844 @option{stat} specify an additional form of image analysis.
11845 @option{out} output video with the specified type of pixel highlighted.
11847 Both options accept the following values:
11851 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
11852 unlike the neighboring pixels of the same field. Examples of temporal outliers
11853 include the results of video dropouts, head clogs, or tape tracking issues.
11856 Identify @var{vertical line repetition}. Vertical line repetition includes
11857 similar rows of pixels within a frame. In born-digital video vertical line
11858 repetition is common, but this pattern is uncommon in video digitized from an
11859 analog source. When it occurs in video that results from the digitization of an
11860 analog source it can indicate concealment from a dropout compensator.
11863 Identify pixels that fall outside of legal broadcast range.
11867 Set the highlight color for the @option{out} option. The default color is
11871 @subsection Examples
11875 Output data of various video metrics:
11877 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
11881 Output specific data about the minimum and maximum values of the Y plane per frame:
11883 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
11887 Playback video while highlighting pixels that are outside of broadcast range in red.
11889 ffplay example.mov -vf signalstats="out=brng:color=red"
11893 Playback video with signalstats metadata drawn over the frame.
11895 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
11898 The contents of signalstat_drawtext.txt used in the command are:
11901 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
11902 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
11903 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
11904 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
11912 Blur the input video without impacting the outlines.
11914 It accepts the following options:
11917 @item luma_radius, lr
11918 Set the luma radius. The option value must be a float number in
11919 the range [0.1,5.0] that specifies the variance of the gaussian filter
11920 used to blur the image (slower if larger). Default value is 1.0.
11922 @item luma_strength, ls
11923 Set the luma strength. The option value must be a float number
11924 in the range [-1.0,1.0] that configures the blurring. A value included
11925 in [0.0,1.0] will blur the image whereas a value included in
11926 [-1.0,0.0] will sharpen the image. Default value is 1.0.
11928 @item luma_threshold, lt
11929 Set the luma threshold used as a coefficient to determine
11930 whether a pixel should be blurred or not. The option value must be an
11931 integer in the range [-30,30]. A value of 0 will filter all the image,
11932 a value included in [0,30] will filter flat areas and a value included
11933 in [-30,0] will filter edges. Default value is 0.
11935 @item chroma_radius, cr
11936 Set the chroma radius. The option value must be a float number in
11937 the range [0.1,5.0] that specifies the variance of the gaussian filter
11938 used to blur the image (slower if larger). Default value is 1.0.
11940 @item chroma_strength, cs
11941 Set the chroma strength. The option value must be a float number
11942 in the range [-1.0,1.0] that configures the blurring. A value included
11943 in [0.0,1.0] will blur the image whereas a value included in
11944 [-1.0,0.0] will sharpen the image. Default value is 1.0.
11946 @item chroma_threshold, ct
11947 Set the chroma threshold used as a coefficient to determine
11948 whether a pixel should be blurred or not. The option value must be an
11949 integer in the range [-30,30]. A value of 0 will filter all the image,
11950 a value included in [0,30] will filter flat areas and a value included
11951 in [-30,0] will filter edges. Default value is 0.
11954 If a chroma option is not explicitly set, the corresponding luma value
11959 Obtain the SSIM (Structural SImilarity Metric) between two input videos.
11961 This filter takes in input two input videos, the first input is
11962 considered the "main" source and is passed unchanged to the
11963 output. The second input is used as a "reference" video for computing
11966 Both video inputs must have the same resolution and pixel format for
11967 this filter to work correctly. Also it assumes that both inputs
11968 have the same number of frames, which are compared one by one.
11970 The filter stores the calculated SSIM of each frame.
11972 The description of the accepted parameters follows.
11975 @item stats_file, f
11976 If specified the filter will use the named file to save the SSIM of
11977 each individual frame. When filename equals "-" the data is sent to
11981 The file printed if @var{stats_file} is selected, contains a sequence of
11982 key/value pairs of the form @var{key}:@var{value} for each compared
11985 A description of each shown parameter follows:
11989 sequential number of the input frame, starting from 1
11991 @item Y, U, V, R, G, B
11992 SSIM of the compared frames for the component specified by the suffix.
11995 SSIM of the compared frames for the whole frame.
11998 Same as above but in dB representation.
12003 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
12004 [main][ref] ssim="stats_file=stats.log" [out]
12007 On this example the input file being processed is compared with the
12008 reference file @file{ref_movie.mpg}. The SSIM of each individual frame
12009 is stored in @file{stats.log}.
12011 Another example with both psnr and ssim at same time:
12013 ffmpeg -i main.mpg -i ref.mpg -lavfi "ssim;[0:v][1:v]psnr" -f null -
12018 Convert between different stereoscopic image formats.
12020 The filters accept the following options:
12024 Set stereoscopic image format of input.
12026 Available values for input image formats are:
12029 side by side parallel (left eye left, right eye right)
12032 side by side crosseye (right eye left, left eye right)
12035 side by side parallel with half width resolution
12036 (left eye left, right eye right)
12039 side by side crosseye with half width resolution
12040 (right eye left, left eye right)
12043 above-below (left eye above, right eye below)
12046 above-below (right eye above, left eye below)
12049 above-below with half height resolution
12050 (left eye above, right eye below)
12053 above-below with half height resolution
12054 (right eye above, left eye below)
12057 alternating frames (left eye first, right eye second)
12060 alternating frames (right eye first, left eye second)
12063 interleaved rows (left eye has top row, right eye starts on next row)
12066 interleaved rows (right eye has top row, left eye starts on next row)
12069 interleaved columns, left eye first
12072 interleaved columns, right eye first
12074 Default value is @samp{sbsl}.
12078 Set stereoscopic image format of output.
12082 side by side parallel (left eye left, right eye right)
12085 side by side crosseye (right eye left, left eye right)
12088 side by side parallel with half width resolution
12089 (left eye left, right eye right)
12092 side by side crosseye with half width resolution
12093 (right eye left, left eye right)
12096 above-below (left eye above, right eye below)
12099 above-below (right eye above, left eye below)
12102 above-below with half height resolution
12103 (left eye above, right eye below)
12106 above-below with half height resolution
12107 (right eye above, left eye below)
12110 alternating frames (left eye first, right eye second)
12113 alternating frames (right eye first, left eye second)
12116 interleaved rows (left eye has top row, right eye starts on next row)
12119 interleaved rows (right eye has top row, left eye starts on next row)
12122 anaglyph red/blue gray
12123 (red filter on left eye, blue filter on right eye)
12126 anaglyph red/green gray
12127 (red filter on left eye, green filter on right eye)
12130 anaglyph red/cyan gray
12131 (red filter on left eye, cyan filter on right eye)
12134 anaglyph red/cyan half colored
12135 (red filter on left eye, cyan filter on right eye)
12138 anaglyph red/cyan color
12139 (red filter on left eye, cyan filter on right eye)
12142 anaglyph red/cyan color optimized with the least squares projection of dubois
12143 (red filter on left eye, cyan filter on right eye)
12146 anaglyph green/magenta gray
12147 (green filter on left eye, magenta filter on right eye)
12150 anaglyph green/magenta half colored
12151 (green filter on left eye, magenta filter on right eye)
12154 anaglyph green/magenta colored
12155 (green filter on left eye, magenta filter on right eye)
12158 anaglyph green/magenta color optimized with the least squares projection of dubois
12159 (green filter on left eye, magenta filter on right eye)
12162 anaglyph yellow/blue gray
12163 (yellow filter on left eye, blue filter on right eye)
12166 anaglyph yellow/blue half colored
12167 (yellow filter on left eye, blue filter on right eye)
12170 anaglyph yellow/blue colored
12171 (yellow filter on left eye, blue filter on right eye)
12174 anaglyph yellow/blue color optimized with the least squares projection of dubois
12175 (yellow filter on left eye, blue filter on right eye)
12178 mono output (left eye only)
12181 mono output (right eye only)
12184 checkerboard, left eye first
12187 checkerboard, right eye first
12190 interleaved columns, left eye first
12193 interleaved columns, right eye first
12196 Default value is @samp{arcd}.
12199 @subsection Examples
12203 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
12209 Convert input video from above below (left eye above, right eye below) to side by side crosseye.
12215 @section streamselect, astreamselect
12216 Select video or audio streams.
12218 The filter accepts the following options:
12222 Set number of inputs. Default is 2.
12225 Set input indexes to remap to outputs.
12228 @subsection Commands
12230 The @code{streamselect} and @code{astreamselect} filter supports the following
12235 Set input indexes to remap to outputs.
12238 @subsection Examples
12242 Select first 5 seconds 1st stream and rest of time 2nd stream:
12244 sendcmd='5.0 streamselect map 1',streamselect=inputs=2:map=0
12248 Same as above, but for audio:
12250 asendcmd='5.0 astreamselect map 1',astreamselect=inputs=2:map=0
12257 Apply a simple postprocessing filter that compresses and decompresses the image
12258 at several (or - in the case of @option{quality} level @code{6} - all) shifts
12259 and average the results.
12261 The filter accepts the following options:
12265 Set quality. This option defines the number of levels for averaging. It accepts
12266 an integer in the range 0-6. If set to @code{0}, the filter will have no
12267 effect. A value of @code{6} means the higher quality. For each increment of
12268 that value the speed drops by a factor of approximately 2. Default value is
12272 Force a constant quantization parameter. If not set, the filter will use the QP
12273 from the video stream (if available).
12276 Set thresholding mode. Available modes are:
12280 Set hard thresholding (default).
12282 Set soft thresholding (better de-ringing effect, but likely blurrier).
12285 @item use_bframe_qp
12286 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
12287 option may cause flicker since the B-Frames have often larger QP. Default is
12288 @code{0} (not enabled).
12294 Draw subtitles on top of input video using the libass library.
12296 To enable compilation of this filter you need to configure FFmpeg with
12297 @code{--enable-libass}. This filter also requires a build with libavcodec and
12298 libavformat to convert the passed subtitles file to ASS (Advanced Substation
12299 Alpha) subtitles format.
12301 The filter accepts the following options:
12305 Set the filename of the subtitle file to read. It must be specified.
12307 @item original_size
12308 Specify the size of the original video, the video for which the ASS file
12309 was composed. For the syntax of this option, check the
12310 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12311 Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
12312 correctly scale the fonts if the aspect ratio has been changed.
12315 Set a directory path containing fonts that can be used by the filter.
12316 These fonts will be used in addition to whatever the font provider uses.
12319 Set subtitles input character encoding. @code{subtitles} filter only. Only
12320 useful if not UTF-8.
12322 @item stream_index, si
12323 Set subtitles stream index. @code{subtitles} filter only.
12326 Override default style or script info parameters of the subtitles. It accepts a
12327 string containing ASS style format @code{KEY=VALUE} couples separated by ",".
12330 If the first key is not specified, it is assumed that the first value
12331 specifies the @option{filename}.
12333 For example, to render the file @file{sub.srt} on top of the input
12334 video, use the command:
12339 which is equivalent to:
12341 subtitles=filename=sub.srt
12344 To render the default subtitles stream from file @file{video.mkv}, use:
12346 subtitles=video.mkv
12349 To render the second subtitles stream from that file, use:
12351 subtitles=video.mkv:si=1
12354 To make the subtitles stream from @file{sub.srt} appear in transparent green
12355 @code{DejaVu Serif}, use:
12357 subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'
12360 @section super2xsai
12362 Scale the input by 2x and smooth using the Super2xSaI (Scale and
12363 Interpolate) pixel art scaling algorithm.
12365 Useful for enlarging pixel art images without reducing sharpness.
12369 Swap two rectangular objects in video.
12371 This filter accepts the following options:
12381 Set 1st rect x coordinate.
12384 Set 1st rect y coordinate.
12387 Set 2nd rect x coordinate.
12390 Set 2nd rect y coordinate.
12392 All expressions are evaluated once for each frame.
12395 The all options are expressions containing the following constants:
12400 The input width and height.
12403 same as @var{w} / @var{h}
12406 input sample aspect ratio
12409 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
12412 The number of the input frame, starting from 0.
12415 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
12418 the position in the file of the input frame, NAN if unknown
12426 Apply telecine process to the video.
12428 This filter accepts the following options:
12437 The default value is @code{top}.
12441 A string of numbers representing the pulldown pattern you wish to apply.
12442 The default value is @code{23}.
12446 Some typical patterns:
12451 24p: 2332 (preferred)
12458 24p: 222222222223 ("Euro pulldown")
12464 Select the most representative frame in a given sequence of consecutive frames.
12466 The filter accepts the following options:
12470 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
12471 will pick one of them, and then handle the next batch of @var{n} frames until
12472 the end. Default is @code{100}.
12475 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
12476 value will result in a higher memory usage, so a high value is not recommended.
12478 @subsection Examples
12482 Extract one picture each 50 frames:
12488 Complete example of a thumbnail creation with @command{ffmpeg}:
12490 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
12496 Tile several successive frames together.
12498 The filter accepts the following options:
12503 Set the grid size (i.e. the number of lines and columns). For the syntax of
12504 this option, check the
12505 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12508 Set the maximum number of frames to render in the given area. It must be less
12509 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
12510 the area will be used.
12513 Set the outer border margin in pixels.
12516 Set the inner border thickness (i.e. the number of pixels between frames). For
12517 more advanced padding options (such as having different values for the edges),
12518 refer to the pad video filter.
12521 Specify the color of the unused area. For the syntax of this option, check the
12522 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
12526 @subsection Examples
12530 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
12532 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
12534 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
12535 duplicating each output frame to accommodate the originally detected frame
12539 Display @code{5} pictures in an area of @code{3x2} frames,
12540 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
12541 mixed flat and named options:
12543 tile=3x2:nb_frames=5:padding=7:margin=2
12547 @section tinterlace
12549 Perform various types of temporal field interlacing.
12551 Frames are counted starting from 1, so the first input frame is
12554 The filter accepts the following options:
12559 Specify the mode of the interlacing. This option can also be specified
12560 as a value alone. See below for a list of values for this option.
12562 Available values are:
12566 Move odd frames into the upper field, even into the lower field,
12567 generating a double height frame at half frame rate.
12571 Frame 1 Frame 2 Frame 3 Frame 4
12573 11111 22222 33333 44444
12574 11111 22222 33333 44444
12575 11111 22222 33333 44444
12576 11111 22222 33333 44444
12590 Only output even frames, odd frames are dropped, generating a frame with
12591 unchanged height at half frame rate.
12596 Frame 1 Frame 2 Frame 3 Frame 4
12598 11111 22222 33333 44444
12599 11111 22222 33333 44444
12600 11111 22222 33333 44444
12601 11111 22222 33333 44444
12611 Only output odd frames, even frames are dropped, generating a frame with
12612 unchanged height at half frame rate.
12617 Frame 1 Frame 2 Frame 3 Frame 4
12619 11111 22222 33333 44444
12620 11111 22222 33333 44444
12621 11111 22222 33333 44444
12622 11111 22222 33333 44444
12632 Expand each frame to full height, but pad alternate lines with black,
12633 generating a frame with double height at the same input frame rate.
12638 Frame 1 Frame 2 Frame 3 Frame 4
12640 11111 22222 33333 44444
12641 11111 22222 33333 44444
12642 11111 22222 33333 44444
12643 11111 22222 33333 44444
12646 11111 ..... 33333 .....
12647 ..... 22222 ..... 44444
12648 11111 ..... 33333 .....
12649 ..... 22222 ..... 44444
12650 11111 ..... 33333 .....
12651 ..... 22222 ..... 44444
12652 11111 ..... 33333 .....
12653 ..... 22222 ..... 44444
12657 @item interleave_top, 4
12658 Interleave the upper field from odd frames with the lower field from
12659 even frames, generating a frame with unchanged height at half frame rate.
12664 Frame 1 Frame 2 Frame 3 Frame 4
12666 11111<- 22222 33333<- 44444
12667 11111 22222<- 33333 44444<-
12668 11111<- 22222 33333<- 44444
12669 11111 22222<- 33333 44444<-
12679 @item interleave_bottom, 5
12680 Interleave the lower field from odd frames with the upper field from
12681 even frames, generating a frame with unchanged height at half frame rate.
12686 Frame 1 Frame 2 Frame 3 Frame 4
12688 11111 22222<- 33333 44444<-
12689 11111<- 22222 33333<- 44444
12690 11111 22222<- 33333 44444<-
12691 11111<- 22222 33333<- 44444
12701 @item interlacex2, 6
12702 Double frame rate with unchanged height. Frames are inserted each
12703 containing the second temporal field from the previous input frame and
12704 the first temporal field from the next input frame. This mode relies on
12705 the top_field_first flag. Useful for interlaced video displays with no
12706 field synchronisation.
12711 Frame 1 Frame 2 Frame 3 Frame 4
12713 11111 22222 33333 44444
12714 11111 22222 33333 44444
12715 11111 22222 33333 44444
12716 11111 22222 33333 44444
12719 11111 22222 22222 33333 33333 44444 44444
12720 11111 11111 22222 22222 33333 33333 44444
12721 11111 22222 22222 33333 33333 44444 44444
12722 11111 11111 22222 22222 33333 33333 44444
12726 Move odd frames into the upper field, even into the lower field,
12727 generating a double height frame at same frame rate.
12731 Frame 1 Frame 2 Frame 3 Frame 4
12733 11111 22222 33333 44444
12734 11111 22222 33333 44444
12735 11111 22222 33333 44444
12736 11111 22222 33333 44444
12739 11111 33333 33333 55555
12740 22222 22222 44444 44444
12741 11111 33333 33333 55555
12742 22222 22222 44444 44444
12743 11111 33333 33333 55555
12744 22222 22222 44444 44444
12745 11111 33333 33333 55555
12746 22222 22222 44444 44444
12751 Numeric values are deprecated but are accepted for backward
12752 compatibility reasons.
12754 Default mode is @code{merge}.
12757 Specify flags influencing the filter process.
12759 Available value for @var{flags} is:
12762 @item low_pass_filter, vlfp
12763 Enable vertical low-pass filtering in the filter.
12764 Vertical low-pass filtering is required when creating an interlaced
12765 destination from a progressive source which contains high-frequency
12766 vertical detail. Filtering will reduce interlace 'twitter' and Moire
12769 Vertical low-pass filtering can only be enabled for @option{mode}
12770 @var{interleave_top} and @var{interleave_bottom}.
12777 Transpose rows with columns in the input video and optionally flip it.
12779 It accepts the following parameters:
12784 Specify the transposition direction.
12786 Can assume the following values:
12788 @item 0, 4, cclock_flip
12789 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
12797 Rotate by 90 degrees clockwise, that is:
12805 Rotate by 90 degrees counterclockwise, that is:
12812 @item 3, 7, clock_flip
12813 Rotate by 90 degrees clockwise and vertically flip, that is:
12821 For values between 4-7, the transposition is only done if the input
12822 video geometry is portrait and not landscape. These values are
12823 deprecated, the @code{passthrough} option should be used instead.
12825 Numerical values are deprecated, and should be dropped in favor of
12826 symbolic constants.
12829 Do not apply the transposition if the input geometry matches the one
12830 specified by the specified value. It accepts the following values:
12833 Always apply transposition.
12835 Preserve portrait geometry (when @var{height} >= @var{width}).
12837 Preserve landscape geometry (when @var{width} >= @var{height}).
12840 Default value is @code{none}.
12843 For example to rotate by 90 degrees clockwise and preserve portrait
12846 transpose=dir=1:passthrough=portrait
12849 The command above can also be specified as:
12851 transpose=1:portrait
12855 Trim the input so that the output contains one continuous subpart of the input.
12857 It accepts the following parameters:
12860 Specify the time of the start of the kept section, i.e. the frame with the
12861 timestamp @var{start} will be the first frame in the output.
12864 Specify the time of the first frame that will be dropped, i.e. the frame
12865 immediately preceding the one with the timestamp @var{end} will be the last
12866 frame in the output.
12869 This is the same as @var{start}, except this option sets the start timestamp
12870 in timebase units instead of seconds.
12873 This is the same as @var{end}, except this option sets the end timestamp
12874 in timebase units instead of seconds.
12877 The maximum duration of the output in seconds.
12880 The number of the first frame that should be passed to the output.
12883 The number of the first frame that should be dropped.
12886 @option{start}, @option{end}, and @option{duration} are expressed as time
12887 duration specifications; see
12888 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
12889 for the accepted syntax.
12891 Note that the first two sets of the start/end options and the @option{duration}
12892 option look at the frame timestamp, while the _frame variants simply count the
12893 frames that pass through the filter. Also note that this filter does not modify
12894 the timestamps. If you wish for the output timestamps to start at zero, insert a
12895 setpts filter after the trim filter.
12897 If multiple start or end options are set, this filter tries to be greedy and
12898 keep all the frames that match at least one of the specified constraints. To keep
12899 only the part that matches all the constraints at once, chain multiple trim
12902 The defaults are such that all the input is kept. So it is possible to set e.g.
12903 just the end values to keep everything before the specified time.
12908 Drop everything except the second minute of input:
12910 ffmpeg -i INPUT -vf trim=60:120
12914 Keep only the first second:
12916 ffmpeg -i INPUT -vf trim=duration=1
12925 Sharpen or blur the input video.
12927 It accepts the following parameters:
12930 @item luma_msize_x, lx
12931 Set the luma matrix horizontal size. It must be an odd integer between
12932 3 and 63. The default value is 5.
12934 @item luma_msize_y, ly
12935 Set the luma matrix vertical size. It must be an odd integer between 3
12936 and 63. The default value is 5.
12938 @item luma_amount, la
12939 Set the luma effect strength. It must be a floating point number, reasonable
12940 values lay between -1.5 and 1.5.
12942 Negative values will blur the input video, while positive values will
12943 sharpen it, a value of zero will disable the effect.
12945 Default value is 1.0.
12947 @item chroma_msize_x, cx
12948 Set the chroma matrix horizontal size. It must be an odd integer
12949 between 3 and 63. The default value is 5.
12951 @item chroma_msize_y, cy
12952 Set the chroma matrix vertical size. It must be an odd integer
12953 between 3 and 63. The default value is 5.
12955 @item chroma_amount, ca
12956 Set the chroma effect strength. It must be a floating point number, reasonable
12957 values lay between -1.5 and 1.5.
12959 Negative values will blur the input video, while positive values will
12960 sharpen it, a value of zero will disable the effect.
12962 Default value is 0.0.
12965 If set to 1, specify using OpenCL capabilities, only available if
12966 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
12970 All parameters are optional and default to the equivalent of the
12971 string '5:5:1.0:5:5:0.0'.
12973 @subsection Examples
12977 Apply strong luma sharpen effect:
12979 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
12983 Apply a strong blur of both luma and chroma parameters:
12985 unsharp=7:7:-2:7:7:-2
12991 Apply ultra slow/simple postprocessing filter that compresses and decompresses
12992 the image at several (or - in the case of @option{quality} level @code{8} - all)
12993 shifts and average the results.
12995 The way this differs from the behavior of spp is that uspp actually encodes &
12996 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
12997 DCT similar to MJPEG.
12999 The filter accepts the following options:
13003 Set quality. This option defines the number of levels for averaging. It accepts
13004 an integer in the range 0-8. If set to @code{0}, the filter will have no
13005 effect. A value of @code{8} means the higher quality. For each increment of
13006 that value the speed drops by a factor of approximately 2. Default value is
13010 Force a constant quantization parameter. If not set, the filter will use the QP
13011 from the video stream (if available).
13014 @section vectorscope
13016 Display 2 color component values in the two dimensional graph (which is called
13019 This filter accepts the following options:
13023 Set vectorscope mode.
13025 It accepts the following values:
13028 Gray values are displayed on graph, higher brightness means more pixels have
13029 same component color value on location in graph. This is the default mode.
13032 Gray values are displayed on graph. Surrounding pixels values which are not
13033 present in video frame are drawn in gradient of 2 color components which are
13034 set by option @code{x} and @code{y}. The 3rd color component is static.
13037 Actual color components values present in video frame are displayed on graph.
13040 Similar as color2 but higher frequency of same values @code{x} and @code{y}
13041 on graph increases value of another color component, which is luminance by
13042 default values of @code{x} and @code{y}.
13045 Actual colors present in video frame are displayed on graph. If two different
13046 colors map to same position on graph then color with higher value of component
13047 not present in graph is picked.
13050 Gray values are displayed on graph. Similar to @code{color} but with 3rd color
13051 component picked from radial gradient.
13055 Set which color component will be represented on X-axis. Default is @code{1}.
13058 Set which color component will be represented on Y-axis. Default is @code{2}.
13061 Set intensity, used by modes: gray, color, color3 and color5 for increasing brightness
13062 of color component which represents frequency of (X, Y) location in graph.
13067 No envelope, this is default.
13070 Instant envelope, even darkest single pixel will be clearly highlighted.
13073 Hold maximum and minimum values presented in graph over time. This way you
13074 can still spot out of range values without constantly looking at vectorscope.
13077 Peak and instant envelope combined together.
13081 Set what kind of graticule to draw.
13089 Set graticule opacity.
13092 Set graticule flags.
13096 Draw graticule for white point.
13099 Draw graticule for black point.
13102 Draw color points short names.
13106 Set background opacity.
13108 @item lthreshold, l
13109 Set low threshold for color component not represented on X or Y axis.
13110 Values lower than this value will be ignored. Default is 0.
13111 Note this value is multiplied with actual max possible value one pixel component
13112 can have. So for 8-bit input and low threshold value of 0.1 actual threshold
13115 @item hthreshold, h
13116 Set high threshold for color component not represented on X or Y axis.
13117 Values higher than this value will be ignored. Default is 1.
13118 Note this value is multiplied with actual max possible value one pixel component
13119 can have. So for 8-bit input and high threshold value of 0.9 actual threshold
13120 is 0.9 * 255 = 230.
13122 @item colorspace, c
13123 Set what kind of colorspace to use when drawing graticule.
13132 @anchor{vidstabdetect}
13133 @section vidstabdetect
13135 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
13136 @ref{vidstabtransform} for pass 2.
13138 This filter generates a file with relative translation and rotation
13139 transform information about subsequent frames, which is then used by
13140 the @ref{vidstabtransform} filter.
13142 To enable compilation of this filter you need to configure FFmpeg with
13143 @code{--enable-libvidstab}.
13145 This filter accepts the following options:
13149 Set the path to the file used to write the transforms information.
13150 Default value is @file{transforms.trf}.
13153 Set how shaky the video is and how quick the camera is. It accepts an
13154 integer in the range 1-10, a value of 1 means little shakiness, a
13155 value of 10 means strong shakiness. Default value is 5.
13158 Set the accuracy of the detection process. It must be a value in the
13159 range 1-15. A value of 1 means low accuracy, a value of 15 means high
13160 accuracy. Default value is 15.
13163 Set stepsize of the search process. The region around minimum is
13164 scanned with 1 pixel resolution. Default value is 6.
13167 Set minimum contrast. Below this value a local measurement field is
13168 discarded. Must be a floating point value in the range 0-1. Default
13172 Set reference frame number for tripod mode.
13174 If enabled, the motion of the frames is compared to a reference frame
13175 in the filtered stream, identified by the specified number. The idea
13176 is to compensate all movements in a more-or-less static scene and keep
13177 the camera view absolutely still.
13179 If set to 0, it is disabled. The frames are counted starting from 1.
13182 Show fields and transforms in the resulting frames. It accepts an
13183 integer in the range 0-2. Default value is 0, which disables any
13187 @subsection Examples
13191 Use default values:
13197 Analyze strongly shaky movie and put the results in file
13198 @file{mytransforms.trf}:
13200 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
13204 Visualize the result of internal transformations in the resulting
13207 vidstabdetect=show=1
13211 Analyze a video with medium shakiness using @command{ffmpeg}:
13213 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
13217 @anchor{vidstabtransform}
13218 @section vidstabtransform
13220 Video stabilization/deshaking: pass 2 of 2,
13221 see @ref{vidstabdetect} for pass 1.
13223 Read a file with transform information for each frame and
13224 apply/compensate them. Together with the @ref{vidstabdetect}
13225 filter this can be used to deshake videos. See also
13226 @url{http://public.hronopik.de/vid.stab}. It is important to also use
13227 the @ref{unsharp} filter, see below.
13229 To enable compilation of this filter you need to configure FFmpeg with
13230 @code{--enable-libvidstab}.
13232 @subsection Options
13236 Set path to the file used to read the transforms. Default value is
13237 @file{transforms.trf}.
13240 Set the number of frames (value*2 + 1) used for lowpass filtering the
13241 camera movements. Default value is 10.
13243 For example a number of 10 means that 21 frames are used (10 in the
13244 past and 10 in the future) to smoothen the motion in the video. A
13245 larger value leads to a smoother video, but limits the acceleration of
13246 the camera (pan/tilt movements). 0 is a special case where a static
13247 camera is simulated.
13250 Set the camera path optimization algorithm.
13252 Accepted values are:
13255 gaussian kernel low-pass filter on camera motion (default)
13257 averaging on transformations
13261 Set maximal number of pixels to translate frames. Default value is -1,
13265 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
13266 value is -1, meaning no limit.
13269 Specify how to deal with borders that may be visible due to movement
13272 Available values are:
13275 keep image information from previous frame (default)
13277 fill the border black
13281 Invert transforms if set to 1. Default value is 0.
13284 Consider transforms as relative to previous frame if set to 1,
13285 absolute if set to 0. Default value is 0.
13288 Set percentage to zoom. A positive value will result in a zoom-in
13289 effect, a negative value in a zoom-out effect. Default value is 0 (no
13293 Set optimal zooming to avoid borders.
13295 Accepted values are:
13300 optimal static zoom value is determined (only very strong movements
13301 will lead to visible borders) (default)
13303 optimal adaptive zoom value is determined (no borders will be
13304 visible), see @option{zoomspeed}
13307 Note that the value given at zoom is added to the one calculated here.
13310 Set percent to zoom maximally each frame (enabled when
13311 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
13315 Specify type of interpolation.
13317 Available values are:
13322 linear only horizontal
13324 linear in both directions (default)
13326 cubic in both directions (slow)
13330 Enable virtual tripod mode if set to 1, which is equivalent to
13331 @code{relative=0:smoothing=0}. Default value is 0.
13333 Use also @code{tripod} option of @ref{vidstabdetect}.
13336 Increase log verbosity if set to 1. Also the detected global motions
13337 are written to the temporary file @file{global_motions.trf}. Default
13341 @subsection Examples
13345 Use @command{ffmpeg} for a typical stabilization with default values:
13347 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
13350 Note the use of the @ref{unsharp} filter which is always recommended.
13353 Zoom in a bit more and load transform data from a given file:
13355 vidstabtransform=zoom=5:input="mytransforms.trf"
13359 Smoothen the video even more:
13361 vidstabtransform=smoothing=30
13367 Flip the input video vertically.
13369 For example, to vertically flip a video with @command{ffmpeg}:
13371 ffmpeg -i in.avi -vf "vflip" out.avi
13377 Make or reverse a natural vignetting effect.
13379 The filter accepts the following options:
13383 Set lens angle expression as a number of radians.
13385 The value is clipped in the @code{[0,PI/2]} range.
13387 Default value: @code{"PI/5"}
13391 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
13395 Set forward/backward mode.
13397 Available modes are:
13400 The larger the distance from the central point, the darker the image becomes.
13403 The larger the distance from the central point, the brighter the image becomes.
13404 This can be used to reverse a vignette effect, though there is no automatic
13405 detection to extract the lens @option{angle} and other settings (yet). It can
13406 also be used to create a burning effect.
13409 Default value is @samp{forward}.
13412 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
13414 It accepts the following values:
13417 Evaluate expressions only once during the filter initialization.
13420 Evaluate expressions for each incoming frame. This is way slower than the
13421 @samp{init} mode since it requires all the scalers to be re-computed, but it
13422 allows advanced dynamic expressions.
13425 Default value is @samp{init}.
13428 Set dithering to reduce the circular banding effects. Default is @code{1}
13432 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
13433 Setting this value to the SAR of the input will make a rectangular vignetting
13434 following the dimensions of the video.
13436 Default is @code{1/1}.
13439 @subsection Expressions
13441 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
13442 following parameters.
13447 input width and height
13450 the number of input frame, starting from 0
13453 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
13454 @var{TB} units, NAN if undefined
13457 frame rate of the input video, NAN if the input frame rate is unknown
13460 the PTS (Presentation TimeStamp) of the filtered video frame,
13461 expressed in seconds, NAN if undefined
13464 time base of the input video
13468 @subsection Examples
13472 Apply simple strong vignetting effect:
13478 Make a flickering vignetting:
13480 vignette='PI/4+random(1)*PI/50':eval=frame
13486 Stack input videos vertically.
13488 All streams must be of same pixel format and of same width.
13490 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
13491 to create same output.
13493 The filter accept the following option:
13497 Set number of input streams. Default is 2.
13500 If set to 1, force the output to terminate when the shortest input
13501 terminates. Default value is 0.
13506 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
13507 Deinterlacing Filter").
13509 Based on the process described by Martin Weston for BBC R&D, and
13510 implemented based on the de-interlace algorithm written by Jim
13511 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
13512 uses filter coefficients calculated by BBC R&D.
13514 There are two sets of filter coefficients, so called "simple":
13515 and "complex". Which set of filter coefficients is used can
13516 be set by passing an optional parameter:
13520 Set the interlacing filter coefficients. Accepts one of the following values:
13524 Simple filter coefficient set.
13526 More-complex filter coefficient set.
13528 Default value is @samp{complex}.
13531 Specify which frames to deinterlace. Accept one of the following values:
13535 Deinterlace all frames,
13537 Only deinterlace frames marked as interlaced.
13540 Default value is @samp{all}.
13544 Video waveform monitor.
13546 The waveform monitor plots color component intensity. By default luminance
13547 only. Each column of the waveform corresponds to a column of pixels in the
13550 It accepts the following options:
13554 Can be either @code{row}, or @code{column}. Default is @code{column}.
13555 In row mode, the graph on the left side represents color component value 0 and
13556 the right side represents value = 255. In column mode, the top side represents
13557 color component value = 0 and bottom side represents value = 255.
13560 Set intensity. Smaller values are useful to find out how many values of the same
13561 luminance are distributed across input rows/columns.
13562 Default value is @code{0.04}. Allowed range is [0, 1].
13565 Set mirroring mode. @code{0} means unmirrored, @code{1} means mirrored.
13566 In mirrored mode, higher values will be represented on the left
13567 side for @code{row} mode and at the top for @code{column} mode. Default is
13568 @code{1} (mirrored).
13572 It accepts the following values:
13575 Presents information identical to that in the @code{parade}, except
13576 that the graphs representing color components are superimposed directly
13579 This display mode makes it easier to spot relative differences or similarities
13580 in overlapping areas of the color components that are supposed to be identical,
13581 such as neutral whites, grays, or blacks.
13584 Display separate graph for the color components side by side in
13585 @code{row} mode or one below the other in @code{column} mode.
13588 Display separate graph for the color components side by side in
13589 @code{column} mode or one below the other in @code{row} mode.
13591 Using this display mode makes it easy to spot color casts in the highlights
13592 and shadows of an image, by comparing the contours of the top and the bottom
13593 graphs of each waveform. Since whites, grays, and blacks are characterized
13594 by exactly equal amounts of red, green, and blue, neutral areas of the picture
13595 should display three waveforms of roughly equal width/height. If not, the
13596 correction is easy to perform by making level adjustments the three waveforms.
13598 Default is @code{stack}.
13600 @item components, c
13601 Set which color components to display. Default is 1, which means only luminance
13602 or red color component if input is in RGB colorspace. If is set for example to
13603 7 it will display all 3 (if) available color components.
13608 No envelope, this is default.
13611 Instant envelope, minimum and maximum values presented in graph will be easily
13612 visible even with small @code{step} value.
13615 Hold minimum and maximum values presented in graph across time. This way you
13616 can still spot out of range values without constantly looking at waveforms.
13619 Peak and instant envelope combined together.
13625 No filtering, this is default.
13628 Luma and chroma combined together.
13631 Similar as above, but shows difference between blue and red chroma.
13634 Displays only chroma.
13637 Displays actual color value on waveform.
13640 Similar as above, but with luma showing frequency of chroma values.
13644 Set which graticule to display.
13648 Do not display graticule.
13651 Display green graticule showing legal broadcast ranges.
13655 Set graticule opacity.
13658 Set graticule flags.
13662 Draw numbers above lines. By default enabled.
13665 Draw dots instead of lines.
13669 Set scale used for displaying graticule.
13676 Default is digital.
13680 Apply the xBR high-quality magnification filter which is designed for pixel
13681 art. It follows a set of edge-detection rules, see
13682 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
13684 It accepts the following option:
13688 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
13689 @code{3xBR} and @code{4} for @code{4xBR}.
13690 Default is @code{3}.
13696 Deinterlace the input video ("yadif" means "yet another deinterlacing
13699 It accepts the following parameters:
13705 The interlacing mode to adopt. It accepts one of the following values:
13708 @item 0, send_frame
13709 Output one frame for each frame.
13710 @item 1, send_field
13711 Output one frame for each field.
13712 @item 2, send_frame_nospatial
13713 Like @code{send_frame}, but it skips the spatial interlacing check.
13714 @item 3, send_field_nospatial
13715 Like @code{send_field}, but it skips the spatial interlacing check.
13718 The default value is @code{send_frame}.
13721 The picture field parity assumed for the input interlaced video. It accepts one
13722 of the following values:
13726 Assume the top field is first.
13728 Assume the bottom field is first.
13730 Enable automatic detection of field parity.
13733 The default value is @code{auto}.
13734 If the interlacing is unknown or the decoder does not export this information,
13735 top field first will be assumed.
13738 Specify which frames to deinterlace. Accept one of the following
13743 Deinterlace all frames.
13744 @item 1, interlaced
13745 Only deinterlace frames marked as interlaced.
13748 The default value is @code{all}.
13753 Apply Zoom & Pan effect.
13755 This filter accepts the following options:
13759 Set the zoom expression. Default is 1.
13763 Set the x and y expression. Default is 0.
13766 Set the duration expression in number of frames.
13767 This sets for how many number of frames effect will last for
13768 single input image.
13771 Set the output image size, default is 'hd720'.
13774 Set the output frame rate, default is '25'.
13777 Each expression can contain the following constants:
13796 Output frame count.
13800 Last calculated 'x' and 'y' position from 'x' and 'y' expression
13801 for current input frame.
13805 'x' and 'y' of last output frame of previous input frame or 0 when there was
13806 not yet such frame (first input frame).
13809 Last calculated zoom from 'z' expression for current input frame.
13812 Last calculated zoom of last output frame of previous input frame.
13815 Number of output frames for current input frame. Calculated from 'd' expression
13816 for each input frame.
13819 number of output frames created for previous input frame
13822 Rational number: input width / input height
13825 sample aspect ratio
13828 display aspect ratio
13832 @subsection Examples
13836 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
13838 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
13842 Zoom-in up to 1.5 and pan always at center of picture:
13844 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
13849 Scale (resize) the input video, using the z.lib library:
13850 https://github.com/sekrit-twc/zimg.
13852 The zscale filter forces the output display aspect ratio to be the same
13853 as the input, by changing the output sample aspect ratio.
13855 If the input image format is different from the format requested by
13856 the next filter, the zscale filter will convert the input to the
13859 @subsection Options
13860 The filter accepts the following options.
13865 Set the output video dimension expression. Default value is the input
13868 If the @var{width} or @var{w} is 0, the input width is used for the output.
13869 If the @var{height} or @var{h} is 0, the input height is used for the output.
13871 If one of the values is -1, the zscale filter will use a value that
13872 maintains the aspect ratio of the input image, calculated from the
13873 other specified dimension. If both of them are -1, the input size is
13876 If one of the values is -n with n > 1, the zscale filter will also use a value
13877 that maintains the aspect ratio of the input image, calculated from the other
13878 specified dimension. After that it will, however, make sure that the calculated
13879 dimension is divisible by n and adjust the value if necessary.
13881 See below for the list of accepted constants for use in the dimension
13885 Set the video size. For the syntax of this option, check the
13886 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13889 Set the dither type.
13891 Possible values are:
13896 @item error_diffusion
13902 Set the resize filter type.
13904 Possible values are:
13914 Default is bilinear.
13917 Set the color range.
13919 Possible values are:
13926 Default is same as input.
13929 Set the color primaries.
13931 Possible values are:
13941 Default is same as input.
13944 Set the transfer characteristics.
13946 Possible values are:
13957 Default is same as input.
13960 Set the colorspace matrix.
13962 Possible value are:
13973 Default is same as input.
13976 Set the input color range.
13978 Possible values are:
13985 Default is same as input.
13987 @item primariesin, pin
13988 Set the input color primaries.
13990 Possible values are:
14000 Default is same as input.
14002 @item transferin, tin
14003 Set the input transfer characteristics.
14005 Possible values are:
14016 Default is same as input.
14018 @item matrixin, min
14019 Set the input colorspace matrix.
14021 Possible value are:
14033 The values of the @option{w} and @option{h} options are expressions
14034 containing the following constants:
14039 The input width and height
14043 These are the same as @var{in_w} and @var{in_h}.
14047 The output (scaled) width and height
14051 These are the same as @var{out_w} and @var{out_h}
14054 The same as @var{iw} / @var{ih}
14057 input sample aspect ratio
14060 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
14064 horizontal and vertical input chroma subsample values. For example for the
14065 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
14069 horizontal and vertical output chroma subsample values. For example for the
14070 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
14076 @c man end VIDEO FILTERS
14078 @chapter Video Sources
14079 @c man begin VIDEO SOURCES
14081 Below is a description of the currently available video sources.
14085 Buffer video frames, and make them available to the filter chain.
14087 This source is mainly intended for a programmatic use, in particular
14088 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
14090 It accepts the following parameters:
14095 Specify the size (width and height) of the buffered video frames. For the
14096 syntax of this option, check the
14097 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14100 The input video width.
14103 The input video height.
14106 A string representing the pixel format of the buffered video frames.
14107 It may be a number corresponding to a pixel format, or a pixel format
14111 Specify the timebase assumed by the timestamps of the buffered frames.
14114 Specify the frame rate expected for the video stream.
14116 @item pixel_aspect, sar
14117 The sample (pixel) aspect ratio of the input video.
14120 Specify the optional parameters to be used for the scale filter which
14121 is automatically inserted when an input change is detected in the
14122 input size or format.
14124 @item hw_frames_ctx
14125 When using a hardware pixel format, this should be a reference to an
14126 AVHWFramesContext describing input frames.
14131 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
14134 will instruct the source to accept video frames with size 320x240 and
14135 with format "yuv410p", assuming 1/24 as the timestamps timebase and
14136 square pixels (1:1 sample aspect ratio).
14137 Since the pixel format with name "yuv410p" corresponds to the number 6
14138 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
14139 this example corresponds to:
14141 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
14144 Alternatively, the options can be specified as a flat string, but this
14145 syntax is deprecated:
14147 @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}]
14151 Create a pattern generated by an elementary cellular automaton.
14153 The initial state of the cellular automaton can be defined through the
14154 @option{filename}, and @option{pattern} options. If such options are
14155 not specified an initial state is created randomly.
14157 At each new frame a new row in the video is filled with the result of
14158 the cellular automaton next generation. The behavior when the whole
14159 frame is filled is defined by the @option{scroll} option.
14161 This source accepts the following options:
14165 Read the initial cellular automaton state, i.e. the starting row, from
14166 the specified file.
14167 In the file, each non-whitespace character is considered an alive
14168 cell, a newline will terminate the row, and further characters in the
14169 file will be ignored.
14172 Read the initial cellular automaton state, i.e. the starting row, from
14173 the specified string.
14175 Each non-whitespace character in the string is considered an alive
14176 cell, a newline will terminate the row, and further characters in the
14177 string will be ignored.
14180 Set the video rate, that is the number of frames generated per second.
14183 @item random_fill_ratio, ratio
14184 Set the random fill ratio for the initial cellular automaton row. It
14185 is a floating point number value ranging from 0 to 1, defaults to
14188 This option is ignored when a file or a pattern is specified.
14190 @item random_seed, seed
14191 Set the seed for filling randomly the initial row, must be an integer
14192 included between 0 and UINT32_MAX. If not specified, or if explicitly
14193 set to -1, the filter will try to use a good random seed on a best
14197 Set the cellular automaton rule, it is a number ranging from 0 to 255.
14198 Default value is 110.
14201 Set the size of the output video. For the syntax of this option, check the
14202 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14204 If @option{filename} or @option{pattern} is specified, the size is set
14205 by default to the width of the specified initial state row, and the
14206 height is set to @var{width} * PHI.
14208 If @option{size} is set, it must contain the width of the specified
14209 pattern string, and the specified pattern will be centered in the
14212 If a filename or a pattern string is not specified, the size value
14213 defaults to "320x518" (used for a randomly generated initial state).
14216 If set to 1, scroll the output upward when all the rows in the output
14217 have been already filled. If set to 0, the new generated row will be
14218 written over the top row just after the bottom row is filled.
14221 @item start_full, full
14222 If set to 1, completely fill the output with generated rows before
14223 outputting the first frame.
14224 This is the default behavior, for disabling set the value to 0.
14227 If set to 1, stitch the left and right row edges together.
14228 This is the default behavior, for disabling set the value to 0.
14231 @subsection Examples
14235 Read the initial state from @file{pattern}, and specify an output of
14238 cellauto=f=pattern:s=200x400
14242 Generate a random initial row with a width of 200 cells, with a fill
14245 cellauto=ratio=2/3:s=200x200
14249 Create a pattern generated by rule 18 starting by a single alive cell
14250 centered on an initial row with width 100:
14252 cellauto=p=@@:s=100x400:full=0:rule=18
14256 Specify a more elaborated initial pattern:
14258 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
14263 @anchor{coreimagesrc}
14264 @section coreimagesrc
14265 Video source generated on GPU using Apple's CoreImage API on OSX.
14267 This video source is a specialized version of the @ref{coreimage} video filter.
14268 Use a core image generator at the beginning of the applied filterchain to
14269 generate the content.
14271 The coreimagesrc video source accepts the following options:
14273 @item list_generators
14274 List all available generators along with all their respective options as well as
14275 possible minimum and maximum values along with the default values.
14277 list_generators=true
14281 Specify the size of the sourced video. For the syntax of this option, check the
14282 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14283 The default value is @code{320x240}.
14286 Specify the frame rate of the sourced video, as the number of frames
14287 generated per second. It has to be a string in the format
14288 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
14289 number or a valid video frame rate abbreviation. The default value is
14293 Set the sample aspect ratio of the sourced video.
14296 Set the duration of the sourced video. See
14297 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
14298 for the accepted syntax.
14300 If not specified, or the expressed duration is negative, the video is
14301 supposed to be generated forever.
14304 Additionally, all options of the @ref{coreimage} video filter are accepted.
14305 A complete filterchain can be used for further processing of the
14306 generated input without CPU-HOST transfer. See @ref{coreimage} documentation
14307 and examples for details.
14309 @subsection Examples
14314 Use CIQRCodeGenerator to create a QR code for the FFmpeg homepage,
14315 given as complete and escaped command-line for Apple's standard bash shell:
14317 ffmpeg -f lavfi -i coreimagesrc=s=100x100:filter=CIQRCodeGenerator@@inputMessage=https\\\\\://FFmpeg.org/@@inputCorrectionLevel=H -frames:v 1 QRCode.png
14319 This example is equivalent to the QRCode example of @ref{coreimage} without the
14320 need for a nullsrc video source.
14324 @section mandelbrot
14326 Generate a Mandelbrot set fractal, and progressively zoom towards the
14327 point specified with @var{start_x} and @var{start_y}.
14329 This source accepts the following options:
14334 Set the terminal pts value. Default value is 400.
14337 Set the terminal scale value.
14338 Must be a floating point value. Default value is 0.3.
14341 Set the inner coloring mode, that is the algorithm used to draw the
14342 Mandelbrot fractal internal region.
14344 It shall assume one of the following values:
14349 Show time until convergence.
14351 Set color based on point closest to the origin of the iterations.
14356 Default value is @var{mincol}.
14359 Set the bailout value. Default value is 10.0.
14362 Set the maximum of iterations performed by the rendering
14363 algorithm. Default value is 7189.
14366 Set outer coloring mode.
14367 It shall assume one of following values:
14369 @item iteration_count
14370 Set iteration cound mode.
14371 @item normalized_iteration_count
14372 set normalized iteration count mode.
14374 Default value is @var{normalized_iteration_count}.
14377 Set frame rate, expressed as number of frames per second. Default
14381 Set frame size. For the syntax of this option, check the "Video
14382 size" section in the ffmpeg-utils manual. Default value is "640x480".
14385 Set the initial scale value. Default value is 3.0.
14388 Set the initial x position. Must be a floating point value between
14389 -100 and 100. Default value is -0.743643887037158704752191506114774.
14392 Set the initial y position. Must be a floating point value between
14393 -100 and 100. Default value is -0.131825904205311970493132056385139.
14398 Generate various test patterns, as generated by the MPlayer test filter.
14400 The size of the generated video is fixed, and is 256x256.
14401 This source is useful in particular for testing encoding features.
14403 This source accepts the following options:
14408 Specify the frame rate of the sourced video, as the number of frames
14409 generated per second. It has to be a string in the format
14410 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
14411 number or a valid video frame rate abbreviation. The default value is
14415 Set the duration of the sourced video. See
14416 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
14417 for the accepted syntax.
14419 If not specified, or the expressed duration is negative, the video is
14420 supposed to be generated forever.
14424 Set the number or the name of the test to perform. Supported tests are:
14440 Default value is "all", which will cycle through the list of all tests.
14445 mptestsrc=t=dc_luma
14448 will generate a "dc_luma" test pattern.
14450 @section frei0r_src
14452 Provide a frei0r source.
14454 To enable compilation of this filter you need to install the frei0r
14455 header and configure FFmpeg with @code{--enable-frei0r}.
14457 This source accepts the following parameters:
14462 The size of the video to generate. For the syntax of this option, check the
14463 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14466 The framerate of the generated video. It may be a string of the form
14467 @var{num}/@var{den} or a frame rate abbreviation.
14470 The name to the frei0r source to load. For more information regarding frei0r and
14471 how to set the parameters, read the @ref{frei0r} section in the video filters
14474 @item filter_params
14475 A '|'-separated list of parameters to pass to the frei0r source.
14479 For example, to generate a frei0r partik0l source with size 200x200
14480 and frame rate 10 which is overlaid on the overlay filter main input:
14482 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
14487 Generate a life pattern.
14489 This source is based on a generalization of John Conway's life game.
14491 The sourced input represents a life grid, each pixel represents a cell
14492 which can be in one of two possible states, alive or dead. Every cell
14493 interacts with its eight neighbours, which are the cells that are
14494 horizontally, vertically, or diagonally adjacent.
14496 At each interaction the grid evolves according to the adopted rule,
14497 which specifies the number of neighbor alive cells which will make a
14498 cell stay alive or born. The @option{rule} option allows one to specify
14501 This source accepts the following options:
14505 Set the file from which to read the initial grid state. In the file,
14506 each non-whitespace character is considered an alive cell, and newline
14507 is used to delimit the end of each row.
14509 If this option is not specified, the initial grid is generated
14513 Set the video rate, that is the number of frames generated per second.
14516 @item random_fill_ratio, ratio
14517 Set the random fill ratio for the initial random grid. It is a
14518 floating point number value ranging from 0 to 1, defaults to 1/PHI.
14519 It is ignored when a file is specified.
14521 @item random_seed, seed
14522 Set the seed for filling the initial random grid, must be an integer
14523 included between 0 and UINT32_MAX. If not specified, or if explicitly
14524 set to -1, the filter will try to use a good random seed on a best
14530 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
14531 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
14532 @var{NS} specifies the number of alive neighbor cells which make a
14533 live cell stay alive, and @var{NB} the number of alive neighbor cells
14534 which make a dead cell to become alive (i.e. to "born").
14535 "s" and "b" can be used in place of "S" and "B", respectively.
14537 Alternatively a rule can be specified by an 18-bits integer. The 9
14538 high order bits are used to encode the next cell state if it is alive
14539 for each number of neighbor alive cells, the low order bits specify
14540 the rule for "borning" new cells. Higher order bits encode for an
14541 higher number of neighbor cells.
14542 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
14543 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
14545 Default value is "S23/B3", which is the original Conway's game of life
14546 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
14547 cells, and will born a new cell if there are three alive cells around
14551 Set the size of the output video. For the syntax of this option, check the
14552 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14554 If @option{filename} is specified, the size is set by default to the
14555 same size of the input file. If @option{size} is set, it must contain
14556 the size specified in the input file, and the initial grid defined in
14557 that file is centered in the larger resulting area.
14559 If a filename is not specified, the size value defaults to "320x240"
14560 (used for a randomly generated initial grid).
14563 If set to 1, stitch the left and right grid edges together, and the
14564 top and bottom edges also. Defaults to 1.
14567 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
14568 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
14569 value from 0 to 255.
14572 Set the color of living (or new born) cells.
14575 Set the color of dead cells. If @option{mold} is set, this is the first color
14576 used to represent a dead cell.
14579 Set mold color, for definitely dead and moldy cells.
14581 For the syntax of these 3 color options, check the "Color" section in the
14582 ffmpeg-utils manual.
14585 @subsection Examples
14589 Read a grid from @file{pattern}, and center it on a grid of size
14592 life=f=pattern:s=300x300
14596 Generate a random grid of size 200x200, with a fill ratio of 2/3:
14598 life=ratio=2/3:s=200x200
14602 Specify a custom rule for evolving a randomly generated grid:
14608 Full example with slow death effect (mold) using @command{ffplay}:
14610 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
14617 @anchor{haldclutsrc}
14619 @anchor{rgbtestsrc}
14621 @anchor{smptehdbars}
14624 @section allrgb, allyuv, color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc, testsrc2
14626 The @code{allrgb} source returns frames of size 4096x4096 of all rgb colors.
14628 The @code{allyuv} source returns frames of size 4096x4096 of all yuv colors.
14630 The @code{color} source provides an uniformly colored input.
14632 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
14633 @ref{haldclut} filter.
14635 The @code{nullsrc} source returns unprocessed video frames. It is
14636 mainly useful to be employed in analysis / debugging tools, or as the
14637 source for filters which ignore the input data.
14639 The @code{rgbtestsrc} source generates an RGB test pattern useful for
14640 detecting RGB vs BGR issues. You should see a red, green and blue
14641 stripe from top to bottom.
14643 The @code{smptebars} source generates a color bars pattern, based on
14644 the SMPTE Engineering Guideline EG 1-1990.
14646 The @code{smptehdbars} source generates a color bars pattern, based on
14647 the SMPTE RP 219-2002.
14649 The @code{testsrc} source generates a test video pattern, showing a
14650 color pattern, a scrolling gradient and a timestamp. This is mainly
14651 intended for testing purposes.
14653 The @code{testsrc2} source is similar to testsrc, but supports more
14654 pixel formats instead of just @code{rgb24}. This allows using it as an
14655 input for other tests without requiring a format conversion.
14657 The sources accept the following parameters:
14662 Specify the color of the source, only available in the @code{color}
14663 source. For the syntax of this option, check the "Color" section in the
14664 ffmpeg-utils manual.
14667 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
14668 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
14669 pixels to be used as identity matrix for 3D lookup tables. Each component is
14670 coded on a @code{1/(N*N)} scale.
14673 Specify the size of the sourced video. For the syntax of this option, check the
14674 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14675 The default value is @code{320x240}.
14677 This option is not available with the @code{haldclutsrc} filter.
14680 Specify the frame rate of the sourced video, as the number of frames
14681 generated per second. It has to be a string in the format
14682 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
14683 number or a valid video frame rate abbreviation. The default value is
14687 Set the sample aspect ratio of the sourced video.
14690 Set the duration of the sourced video. See
14691 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
14692 for the accepted syntax.
14694 If not specified, or the expressed duration is negative, the video is
14695 supposed to be generated forever.
14698 Set the number of decimals to show in the timestamp, only available in the
14699 @code{testsrc} source.
14701 The displayed timestamp value will correspond to the original
14702 timestamp value multiplied by the power of 10 of the specified
14703 value. Default value is 0.
14706 For example the following:
14708 testsrc=duration=5.3:size=qcif:rate=10
14711 will generate a video with a duration of 5.3 seconds, with size
14712 176x144 and a frame rate of 10 frames per second.
14714 The following graph description will generate a red source
14715 with an opacity of 0.2, with size "qcif" and a frame rate of 10
14718 color=c=red@@0.2:s=qcif:r=10
14721 If the input content is to be ignored, @code{nullsrc} can be used. The
14722 following command generates noise in the luminance plane by employing
14723 the @code{geq} filter:
14725 nullsrc=s=256x256, geq=random(1)*255:128:128
14728 @subsection Commands
14730 The @code{color} source supports the following commands:
14734 Set the color of the created image. Accepts the same syntax of the
14735 corresponding @option{color} option.
14738 @c man end VIDEO SOURCES
14740 @chapter Video Sinks
14741 @c man begin VIDEO SINKS
14743 Below is a description of the currently available video sinks.
14745 @section buffersink
14747 Buffer video frames, and make them available to the end of the filter
14750 This sink is mainly intended for programmatic use, in particular
14751 through the interface defined in @file{libavfilter/buffersink.h}
14752 or the options system.
14754 It accepts a pointer to an AVBufferSinkContext structure, which
14755 defines the incoming buffers' formats, to be passed as the opaque
14756 parameter to @code{avfilter_init_filter} for initialization.
14760 Null video sink: do absolutely nothing with the input video. It is
14761 mainly useful as a template and for use in analysis / debugging
14764 @c man end VIDEO SINKS
14766 @chapter Multimedia Filters
14767 @c man begin MULTIMEDIA FILTERS
14769 Below is a description of the currently available multimedia filters.
14771 @section ahistogram
14773 Convert input audio to a video output, displaying the volume histogram.
14775 The filter accepts the following options:
14779 Specify how histogram is calculated.
14781 It accepts the following values:
14784 Use single histogram for all channels.
14786 Use separate histogram for each channel.
14788 Default is @code{single}.
14791 Set frame rate, expressed as number of frames per second. Default
14795 Specify the video size for the output. For the syntax of this option, check the
14796 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14797 Default value is @code{hd720}.
14802 It accepts the following values:
14813 reverse logarithmic
14815 Default is @code{log}.
14818 Set amplitude scale.
14820 It accepts the following values:
14827 Default is @code{log}.
14830 Set how much frames to accumulate in histogram.
14831 Defauls is 1. Setting this to -1 accumulates all frames.
14834 Set histogram ratio of window height.
14837 Set sonogram sliding.
14839 It accepts the following values:
14842 replace old rows with new ones.
14844 scroll from top to bottom.
14846 Default is @code{replace}.
14849 @section aphasemeter
14851 Convert input audio to a video output, displaying the audio phase.
14853 The filter accepts the following options:
14857 Set the output frame rate. Default value is @code{25}.
14860 Set the video size for the output. For the syntax of this option, check the
14861 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14862 Default value is @code{800x400}.
14867 Specify the red, green, blue contrast. Default values are @code{2},
14868 @code{7} and @code{1}.
14869 Allowed range is @code{[0, 255]}.
14872 Set color which will be used for drawing median phase. If color is
14873 @code{none} which is default, no median phase value will be drawn.
14876 The filter also exports the frame metadata @code{lavfi.aphasemeter.phase} which
14877 represents mean phase of current audio frame. Value is in range @code{[-1, 1]}.
14878 The @code{-1} means left and right channels are completely out of phase and
14879 @code{1} means channels are in phase.
14881 @section avectorscope
14883 Convert input audio to a video output, representing the audio vector
14886 The filter is used to measure the difference between channels of stereo
14887 audio stream. A monoaural signal, consisting of identical left and right
14888 signal, results in straight vertical line. Any stereo separation is visible
14889 as a deviation from this line, creating a Lissajous figure.
14890 If the straight (or deviation from it) but horizontal line appears this
14891 indicates that the left and right channels are out of phase.
14893 The filter accepts the following options:
14897 Set the vectorscope mode.
14899 Available values are:
14902 Lissajous rotated by 45 degrees.
14905 Same as above but not rotated.
14908 Shape resembling half of circle.
14911 Default value is @samp{lissajous}.
14914 Set the video size for the output. For the syntax of this option, check the
14915 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
14916 Default value is @code{400x400}.
14919 Set the output frame rate. Default value is @code{25}.
14925 Specify the red, green, blue and alpha contrast. Default values are @code{40},
14926 @code{160}, @code{80} and @code{255}.
14927 Allowed range is @code{[0, 255]}.
14933 Specify the red, green, blue and alpha fade. Default values are @code{15},
14934 @code{10}, @code{5} and @code{5}.
14935 Allowed range is @code{[0, 255]}.
14938 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
14941 Set the vectorscope drawing mode.
14943 Available values are:
14946 Draw dot for each sample.
14949 Draw line between previous and current sample.
14952 Default value is @samp{dot}.
14955 @subsection Examples
14959 Complete example using @command{ffplay}:
14961 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
14962 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
14966 @section bench, abench
14968 Benchmark part of a filtergraph.
14970 The filter accepts the following options:
14974 Start or stop a timer.
14976 Available values are:
14979 Get the current time, set it as frame metadata (using the key
14980 @code{lavfi.bench.start_time}), and forward the frame to the next filter.
14983 Get the current time and fetch the @code{lavfi.bench.start_time} metadata from
14984 the input frame metadata to get the time difference. Time difference, average,
14985 maximum and minimum time (respectively @code{t}, @code{avg}, @code{max} and
14986 @code{min}) are then printed. The timestamps are expressed in seconds.
14990 @subsection Examples
14994 Benchmark @ref{selectivecolor} filter:
14996 bench=start,selectivecolor=reds=-.2 .12 -.49,bench=stop
15002 Concatenate audio and video streams, joining them together one after the
15005 The filter works on segments of synchronized video and audio streams. All
15006 segments must have the same number of streams of each type, and that will
15007 also be the number of streams at output.
15009 The filter accepts the following options:
15014 Set the number of segments. Default is 2.
15017 Set the number of output video streams, that is also the number of video
15018 streams in each segment. Default is 1.
15021 Set the number of output audio streams, that is also the number of audio
15022 streams in each segment. Default is 0.
15025 Activate unsafe mode: do not fail if segments have a different format.
15029 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
15030 @var{a} audio outputs.
15032 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
15033 segment, in the same order as the outputs, then the inputs for the second
15036 Related streams do not always have exactly the same duration, for various
15037 reasons including codec frame size or sloppy authoring. For that reason,
15038 related synchronized streams (e.g. a video and its audio track) should be
15039 concatenated at once. The concat filter will use the duration of the longest
15040 stream in each segment (except the last one), and if necessary pad shorter
15041 audio streams with silence.
15043 For this filter to work correctly, all segments must start at timestamp 0.
15045 All corresponding streams must have the same parameters in all segments; the
15046 filtering system will automatically select a common pixel format for video
15047 streams, and a common sample format, sample rate and channel layout for
15048 audio streams, but other settings, such as resolution, must be converted
15049 explicitly by the user.
15051 Different frame rates are acceptable but will result in variable frame rate
15052 at output; be sure to configure the output file to handle it.
15054 @subsection Examples
15058 Concatenate an opening, an episode and an ending, all in bilingual version
15059 (video in stream 0, audio in streams 1 and 2):
15061 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
15062 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
15063 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
15064 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
15068 Concatenate two parts, handling audio and video separately, using the
15069 (a)movie sources, and adjusting the resolution:
15071 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
15072 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
15073 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
15075 Note that a desync will happen at the stitch if the audio and video streams
15076 do not have exactly the same duration in the first file.
15083 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
15084 it unchanged. By default, it logs a message at a frequency of 10Hz with the
15085 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
15086 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
15088 The filter also has a video output (see the @var{video} option) with a real
15089 time graph to observe the loudness evolution. The graphic contains the logged
15090 message mentioned above, so it is not printed anymore when this option is set,
15091 unless the verbose logging is set. The main graphing area contains the
15092 short-term loudness (3 seconds of analysis), and the gauge on the right is for
15093 the momentary loudness (400 milliseconds).
15095 More information about the Loudness Recommendation EBU R128 on
15096 @url{http://tech.ebu.ch/loudness}.
15098 The filter accepts the following options:
15103 Activate the video output. The audio stream is passed unchanged whether this
15104 option is set or no. The video stream will be the first output stream if
15105 activated. Default is @code{0}.
15108 Set the video size. This option is for video only. For the syntax of this
15110 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15111 Default and minimum resolution is @code{640x480}.
15114 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
15115 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
15116 other integer value between this range is allowed.
15119 Set metadata injection. If set to @code{1}, the audio input will be segmented
15120 into 100ms output frames, each of them containing various loudness information
15121 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
15123 Default is @code{0}.
15126 Force the frame logging level.
15128 Available values are:
15131 information logging level
15133 verbose logging level
15136 By default, the logging level is set to @var{info}. If the @option{video} or
15137 the @option{metadata} options are set, it switches to @var{verbose}.
15142 Available modes can be cumulated (the option is a @code{flag} type). Possible
15146 Disable any peak mode (default).
15148 Enable sample-peak mode.
15150 Simple peak mode looking for the higher sample value. It logs a message
15151 for sample-peak (identified by @code{SPK}).
15153 Enable true-peak mode.
15155 If enabled, the peak lookup is done on an over-sampled version of the input
15156 stream for better peak accuracy. It logs a message for true-peak.
15157 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
15158 This mode requires a build with @code{libswresample}.
15162 Treat mono input files as "dual mono". If a mono file is intended for playback
15163 on a stereo system, its EBU R128 measurement will be perceptually incorrect.
15164 If set to @code{true}, this option will compensate for this effect.
15165 Multi-channel input files are not affected by this option.
15168 Set a specific pan law to be used for the measurement of dual mono files.
15169 This parameter is optional, and has a default value of -3.01dB.
15172 @subsection Examples
15176 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
15178 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
15182 Run an analysis with @command{ffmpeg}:
15184 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
15188 @section interleave, ainterleave
15190 Temporally interleave frames from several inputs.
15192 @code{interleave} works with video inputs, @code{ainterleave} with audio.
15194 These filters read frames from several inputs and send the oldest
15195 queued frame to the output.
15197 Input streams must have a well defined, monotonically increasing frame
15200 In order to submit one frame to output, these filters need to enqueue
15201 at least one frame for each input, so they cannot work in case one
15202 input is not yet terminated and will not receive incoming frames.
15204 For example consider the case when one input is a @code{select} filter
15205 which always drop input frames. The @code{interleave} filter will keep
15206 reading from that input, but it will never be able to send new frames
15207 to output until the input will send an end-of-stream signal.
15209 Also, depending on inputs synchronization, the filters will drop
15210 frames in case one input receives more frames than the other ones, and
15211 the queue is already filled.
15213 These filters accept the following options:
15217 Set the number of different inputs, it is 2 by default.
15220 @subsection Examples
15224 Interleave frames belonging to different streams using @command{ffmpeg}:
15226 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
15230 Add flickering blur effect:
15232 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
15236 @section perms, aperms
15238 Set read/write permissions for the output frames.
15240 These filters are mainly aimed at developers to test direct path in the
15241 following filter in the filtergraph.
15243 The filters accept the following options:
15247 Select the permissions mode.
15249 It accepts the following values:
15252 Do nothing. This is the default.
15254 Set all the output frames read-only.
15256 Set all the output frames directly writable.
15258 Make the frame read-only if writable, and writable if read-only.
15260 Set each output frame read-only or writable randomly.
15264 Set the seed for the @var{random} mode, must be an integer included between
15265 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
15266 @code{-1}, the filter will try to use a good random seed on a best effort
15270 Note: in case of auto-inserted filter between the permission filter and the
15271 following one, the permission might not be received as expected in that
15272 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
15273 perms/aperms filter can avoid this problem.
15275 @section realtime, arealtime
15277 Slow down filtering to match real time approximatively.
15279 These filters will pause the filtering for a variable amount of time to
15280 match the output rate with the input timestamps.
15281 They are similar to the @option{re} option to @code{ffmpeg}.
15283 They accept the following options:
15287 Time limit for the pauses. Any pause longer than that will be considered
15288 a timestamp discontinuity and reset the timer. Default is 2 seconds.
15291 @section select, aselect
15293 Select frames to pass in output.
15295 This filter accepts the following options:
15300 Set expression, which is evaluated for each input frame.
15302 If the expression is evaluated to zero, the frame is discarded.
15304 If the evaluation result is negative or NaN, the frame is sent to the
15305 first output; otherwise it is sent to the output with index
15306 @code{ceil(val)-1}, assuming that the input index starts from 0.
15308 For example a value of @code{1.2} corresponds to the output with index
15309 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
15312 Set the number of outputs. The output to which to send the selected
15313 frame is based on the result of the evaluation. Default value is 1.
15316 The expression can contain the following constants:
15320 The (sequential) number of the filtered frame, starting from 0.
15323 The (sequential) number of the selected frame, starting from 0.
15325 @item prev_selected_n
15326 The sequential number of the last selected frame. It's NAN if undefined.
15329 The timebase of the input timestamps.
15332 The PTS (Presentation TimeStamp) of the filtered video frame,
15333 expressed in @var{TB} units. It's NAN if undefined.
15336 The PTS of the filtered video frame,
15337 expressed in seconds. It's NAN if undefined.
15340 The PTS of the previously filtered video frame. It's NAN if undefined.
15342 @item prev_selected_pts
15343 The PTS of the last previously filtered video frame. It's NAN if undefined.
15345 @item prev_selected_t
15346 The PTS of the last previously selected video frame. It's NAN if undefined.
15349 The PTS of the first video frame in the video. It's NAN if undefined.
15352 The time of the first video frame in the video. It's NAN if undefined.
15354 @item pict_type @emph{(video only)}
15355 The type of the filtered frame. It can assume one of the following
15367 @item interlace_type @emph{(video only)}
15368 The frame interlace type. It can assume one of the following values:
15371 The frame is progressive (not interlaced).
15373 The frame is top-field-first.
15375 The frame is bottom-field-first.
15378 @item consumed_sample_n @emph{(audio only)}
15379 the number of selected samples before the current frame
15381 @item samples_n @emph{(audio only)}
15382 the number of samples in the current frame
15384 @item sample_rate @emph{(audio only)}
15385 the input sample rate
15388 This is 1 if the filtered frame is a key-frame, 0 otherwise.
15391 the position in the file of the filtered frame, -1 if the information
15392 is not available (e.g. for synthetic video)
15394 @item scene @emph{(video only)}
15395 value between 0 and 1 to indicate a new scene; a low value reflects a low
15396 probability for the current frame to introduce a new scene, while a higher
15397 value means the current frame is more likely to be one (see the example below)
15399 @item concatdec_select
15400 The concat demuxer can select only part of a concat input file by setting an
15401 inpoint and an outpoint, but the output packets may not be entirely contained
15402 in the selected interval. By using this variable, it is possible to skip frames
15403 generated by the concat demuxer which are not exactly contained in the selected
15406 This works by comparing the frame pts against the @var{lavf.concat.start_time}
15407 and the @var{lavf.concat.duration} packet metadata values which are also
15408 present in the decoded frames.
15410 The @var{concatdec_select} variable is -1 if the frame pts is at least
15411 start_time and either the duration metadata is missing or the frame pts is less
15412 than start_time + duration, 0 otherwise, and NaN if the start_time metadata is
15415 That basically means that an input frame is selected if its pts is within the
15416 interval set by the concat demuxer.
15420 The default value of the select expression is "1".
15422 @subsection Examples
15426 Select all frames in input:
15431 The example above is the same as:
15443 Select only I-frames:
15445 select='eq(pict_type\,I)'
15449 Select one frame every 100:
15451 select='not(mod(n\,100))'
15455 Select only frames contained in the 10-20 time interval:
15457 select=between(t\,10\,20)
15461 Select only I frames contained in the 10-20 time interval:
15463 select=between(t\,10\,20)*eq(pict_type\,I)
15467 Select frames with a minimum distance of 10 seconds:
15469 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
15473 Use aselect to select only audio frames with samples number > 100:
15475 aselect='gt(samples_n\,100)'
15479 Create a mosaic of the first scenes:
15481 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
15484 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
15488 Send even and odd frames to separate outputs, and compose them:
15490 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
15494 Select useful frames from an ffconcat file which is using inpoints and
15495 outpoints but where the source files are not intra frame only.
15497 ffmpeg -copyts -vsync 0 -segment_time_metadata 1 -i input.ffconcat -vf select=concatdec_select -af aselect=concatdec_select output.avi
15501 @section sendcmd, asendcmd
15503 Send commands to filters in the filtergraph.
15505 These filters read commands to be sent to other filters in the
15508 @code{sendcmd} must be inserted between two video filters,
15509 @code{asendcmd} must be inserted between two audio filters, but apart
15510 from that they act the same way.
15512 The specification of commands can be provided in the filter arguments
15513 with the @var{commands} option, or in a file specified by the
15514 @var{filename} option.
15516 These filters accept the following options:
15519 Set the commands to be read and sent to the other filters.
15521 Set the filename of the commands to be read and sent to the other
15525 @subsection Commands syntax
15527 A commands description consists of a sequence of interval
15528 specifications, comprising a list of commands to be executed when a
15529 particular event related to that interval occurs. The occurring event
15530 is typically the current frame time entering or leaving a given time
15533 An interval is specified by the following syntax:
15535 @var{START}[-@var{END}] @var{COMMANDS};
15538 The time interval is specified by the @var{START} and @var{END} times.
15539 @var{END} is optional and defaults to the maximum time.
15541 The current frame time is considered within the specified interval if
15542 it is included in the interval [@var{START}, @var{END}), that is when
15543 the time is greater or equal to @var{START} and is lesser than
15546 @var{COMMANDS} consists of a sequence of one or more command
15547 specifications, separated by ",", relating to that interval. The
15548 syntax of a command specification is given by:
15550 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
15553 @var{FLAGS} is optional and specifies the type of events relating to
15554 the time interval which enable sending the specified command, and must
15555 be a non-null sequence of identifier flags separated by "+" or "|" and
15556 enclosed between "[" and "]".
15558 The following flags are recognized:
15561 The command is sent when the current frame timestamp enters the
15562 specified interval. In other words, the command is sent when the
15563 previous frame timestamp was not in the given interval, and the
15567 The command is sent when the current frame timestamp leaves the
15568 specified interval. In other words, the command is sent when the
15569 previous frame timestamp was in the given interval, and the
15573 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
15576 @var{TARGET} specifies the target of the command, usually the name of
15577 the filter class or a specific filter instance name.
15579 @var{COMMAND} specifies the name of the command for the target filter.
15581 @var{ARG} is optional and specifies the optional list of argument for
15582 the given @var{COMMAND}.
15584 Between one interval specification and another, whitespaces, or
15585 sequences of characters starting with @code{#} until the end of line,
15586 are ignored and can be used to annotate comments.
15588 A simplified BNF description of the commands specification syntax
15591 @var{COMMAND_FLAG} ::= "enter" | "leave"
15592 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
15593 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
15594 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
15595 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
15596 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
15599 @subsection Examples
15603 Specify audio tempo change at second 4:
15605 asendcmd=c='4.0 atempo tempo 1.5',atempo
15609 Specify a list of drawtext and hue commands in a file.
15611 # show text in the interval 5-10
15612 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
15613 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
15615 # desaturate the image in the interval 15-20
15616 15.0-20.0 [enter] hue s 0,
15617 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
15619 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
15621 # apply an exponential saturation fade-out effect, starting from time 25
15622 25 [enter] hue s exp(25-t)
15625 A filtergraph allowing to read and process the above command list
15626 stored in a file @file{test.cmd}, can be specified with:
15628 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
15633 @section setpts, asetpts
15635 Change the PTS (presentation timestamp) of the input frames.
15637 @code{setpts} works on video frames, @code{asetpts} on audio frames.
15639 This filter accepts the following options:
15644 The expression which is evaluated for each frame to construct its timestamp.
15648 The expression is evaluated through the eval API and can contain the following
15653 frame rate, only defined for constant frame-rate video
15656 The presentation timestamp in input
15659 The count of the input frame for video or the number of consumed samples,
15660 not including the current frame for audio, starting from 0.
15662 @item NB_CONSUMED_SAMPLES
15663 The number of consumed samples, not including the current frame (only
15666 @item NB_SAMPLES, S
15667 The number of samples in the current frame (only audio)
15669 @item SAMPLE_RATE, SR
15670 The audio sample rate.
15673 The PTS of the first frame.
15676 the time in seconds of the first frame
15679 State whether the current frame is interlaced.
15682 the time in seconds of the current frame
15685 original position in the file of the frame, or undefined if undefined
15686 for the current frame
15689 The previous input PTS.
15692 previous input time in seconds
15695 The previous output PTS.
15698 previous output time in seconds
15701 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
15705 The wallclock (RTC) time at the start of the movie in microseconds.
15708 The timebase of the input timestamps.
15712 @subsection Examples
15716 Start counting PTS from zero
15718 setpts=PTS-STARTPTS
15722 Apply fast motion effect:
15728 Apply slow motion effect:
15734 Set fixed rate of 25 frames per second:
15740 Set fixed rate 25 fps with some jitter:
15742 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
15746 Apply an offset of 10 seconds to the input PTS:
15752 Generate timestamps from a "live source" and rebase onto the current timebase:
15754 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
15758 Generate timestamps by counting samples:
15765 @section settb, asettb
15767 Set the timebase to use for the output frames timestamps.
15768 It is mainly useful for testing timebase configuration.
15770 It accepts the following parameters:
15775 The expression which is evaluated into the output timebase.
15779 The value for @option{tb} is an arithmetic expression representing a
15780 rational. The expression can contain the constants "AVTB" (the default
15781 timebase), "intb" (the input timebase) and "sr" (the sample rate,
15782 audio only). Default value is "intb".
15784 @subsection Examples
15788 Set the timebase to 1/25:
15794 Set the timebase to 1/10:
15800 Set the timebase to 1001/1000:
15806 Set the timebase to 2*intb:
15812 Set the default timebase value:
15819 Convert input audio to a video output representing frequency spectrum
15820 logarithmically using Brown-Puckette constant Q transform algorithm with
15821 direct frequency domain coefficient calculation (but the transform itself
15822 is not really constant Q, instead the Q factor is actually variable/clamped),
15823 with musical tone scale, from E0 to D#10.
15825 The filter accepts the following options:
15829 Specify the video size for the output. It must be even. For the syntax of this option,
15830 check the @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
15831 Default value is @code{1920x1080}.
15834 Set the output frame rate. Default value is @code{25}.
15837 Set the bargraph height. It must be even. Default value is @code{-1} which
15838 computes the bargraph height automatically.
15841 Set the axis height. It must be even. Default value is @code{-1} which computes
15842 the axis height automatically.
15845 Set the sonogram height. It must be even. Default value is @code{-1} which
15846 computes the sonogram height automatically.
15849 Set the fullhd resolution. This option is deprecated, use @var{size}, @var{s}
15850 instead. Default value is @code{1}.
15852 @item sono_v, volume
15853 Specify the sonogram volume expression. It can contain variables:
15856 the @var{bar_v} evaluated expression
15857 @item frequency, freq, f
15858 the frequency where it is evaluated
15859 @item timeclamp, tc
15860 the value of @var{timeclamp} option
15864 @item a_weighting(f)
15865 A-weighting of equal loudness
15866 @item b_weighting(f)
15867 B-weighting of equal loudness
15868 @item c_weighting(f)
15869 C-weighting of equal loudness.
15871 Default value is @code{16}.
15873 @item bar_v, volume2
15874 Specify the bargraph volume expression. It can contain variables:
15877 the @var{sono_v} evaluated expression
15878 @item frequency, freq, f
15879 the frequency where it is evaluated
15880 @item timeclamp, tc
15881 the value of @var{timeclamp} option
15885 @item a_weighting(f)
15886 A-weighting of equal loudness
15887 @item b_weighting(f)
15888 B-weighting of equal loudness
15889 @item c_weighting(f)
15890 C-weighting of equal loudness.
15892 Default value is @code{sono_v}.
15894 @item sono_g, gamma
15895 Specify the sonogram gamma. Lower gamma makes the spectrum more contrast,
15896 higher gamma makes the spectrum having more range. Default value is @code{3}.
15897 Acceptable range is @code{[1, 7]}.
15899 @item bar_g, gamma2
15900 Specify the bargraph gamma. Default value is @code{1}. Acceptable range is
15903 @item timeclamp, tc
15904 Specify the transform timeclamp. At low frequency, there is trade-off between
15905 accuracy in time domain and frequency domain. If timeclamp is lower,
15906 event in time domain is represented more accurately (such as fast bass drum),
15907 otherwise event in frequency domain is represented more accurately
15908 (such as bass guitar). Acceptable range is @code{[0.1, 1]}. Default value is @code{0.17}.
15911 Specify the transform base frequency. Default value is @code{20.01523126408007475},
15912 which is frequency 50 cents below E0. Acceptable range is @code{[10, 100000]}.
15915 Specify the transform end frequency. Default value is @code{20495.59681441799654},
15916 which is frequency 50 cents above D#10. Acceptable range is @code{[10, 100000]}.
15919 This option is deprecated and ignored.
15922 Specify the transform length in time domain. Use this option to control accuracy
15923 trade-off between time domain and frequency domain at every frequency sample.
15924 It can contain variables:
15926 @item frequency, freq, f
15927 the frequency where it is evaluated
15928 @item timeclamp, tc
15929 the value of @var{timeclamp} option.
15931 Default value is @code{384*tc/(384+tc*f)}.
15934 Specify the transform count for every video frame. Default value is @code{6}.
15935 Acceptable range is @code{[1, 30]}.
15938 Specify the transform count for every single pixel. Default value is @code{0},
15939 which makes it computed automatically. Acceptable range is @code{[0, 10]}.
15942 Specify font file for use with freetype to draw the axis. If not specified,
15943 use embedded font. Note that drawing with font file or embedded font is not
15944 implemented with custom @var{basefreq} and @var{endfreq}, use @var{axisfile}
15948 Specify font color expression. This is arithmetic expression that should return
15949 integer value 0xRRGGBB. It can contain variables:
15951 @item frequency, freq, f
15952 the frequency where it is evaluated
15953 @item timeclamp, tc
15954 the value of @var{timeclamp} option
15959 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
15960 @item r(x), g(x), b(x)
15961 red, green, and blue value of intensity x.
15963 Default value is @code{st(0, (midi(f)-59.5)/12);
15964 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
15965 r(1-ld(1)) + b(ld(1))}.
15968 Specify image file to draw the axis. This option override @var{fontfile} and
15969 @var{fontcolor} option.
15972 Enable/disable drawing text to the axis. If it is set to @code{0}, drawing to
15973 the axis is disabled, ignoring @var{fontfile} and @var{axisfile} option.
15974 Default value is @code{1}.
15978 @subsection Examples
15982 Playing audio while showing the spectrum:
15984 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
15988 Same as above, but with frame rate 30 fps:
15990 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
15994 Playing at 1280x720:
15996 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=s=1280x720:count=4 [out0]'
16000 Disable sonogram display:
16006 A1 and its harmonics: A1, A2, (near)E3, A3:
16008 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),
16009 asplit[a][out1]; [a] showcqt [out0]'
16013 Same as above, but with more accuracy in frequency domain:
16015 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),
16016 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
16022 bar_v=10:sono_v=bar_v*a_weighting(f)
16026 Custom gamma, now spectrum is linear to the amplitude.
16032 Custom tlength equation:
16034 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)))'
16038 Custom fontcolor and fontfile, C-note is colored green, others are colored blue:
16040 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))':fontfile=myfont.ttf
16044 Custom frequency range with custom axis using image file:
16046 axisfile=myaxis.png:basefreq=40:endfreq=10000
16052 Convert input audio to video output representing the audio power spectrum.
16053 Audio amplitude is on Y-axis while frequency is on X-axis.
16055 The filter accepts the following options:
16059 Specify size of video. For the syntax of this option, check the
16060 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16061 Default is @code{1024x512}.
16065 This set how each frequency bin will be represented.
16067 It accepts the following values:
16073 Default is @code{bar}.
16076 Set amplitude scale.
16078 It accepts the following values:
16092 Default is @code{log}.
16095 Set frequency scale.
16097 It accepts the following values:
16106 Reverse logarithmic scale.
16108 Default is @code{lin}.
16113 It accepts the following values:
16129 Default is @code{w2048}
16132 Set windowing function.
16134 It accepts the following values:
16152 Default is @code{hanning}.
16155 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
16156 which means optimal overlap for selected window function will be picked.
16159 Set time averaging. Setting this to 0 will display current maximal peaks.
16160 Default is @code{1}, which means time averaging is disabled.
16163 Specify list of colors separated by space or by '|' which will be used to
16164 draw channel frequencies. Unrecognized or missing colors will be replaced
16168 Set channel display mode.
16170 It accepts the following values:
16175 Default is @code{combined}.
16179 @anchor{showspectrum}
16180 @section showspectrum
16182 Convert input audio to a video output, representing the audio frequency
16185 The filter accepts the following options:
16189 Specify the video size for the output. For the syntax of this option, check the
16190 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16191 Default value is @code{640x512}.
16194 Specify how the spectrum should slide along the window.
16196 It accepts the following values:
16199 the samples start again on the left when they reach the right
16201 the samples scroll from right to left
16203 the samples scroll from left to right
16205 frames are only produced when the samples reach the right
16208 Default value is @code{replace}.
16211 Specify display mode.
16213 It accepts the following values:
16216 all channels are displayed in the same row
16218 all channels are displayed in separate rows
16221 Default value is @samp{combined}.
16224 Specify display color mode.
16226 It accepts the following values:
16229 each channel is displayed in a separate color
16231 each channel is displayed using the same color scheme
16233 each channel is displayed using the rainbow color scheme
16235 each channel is displayed using the moreland color scheme
16237 each channel is displayed using the nebulae color scheme
16239 each channel is displayed using the fire color scheme
16241 each channel is displayed using the fiery color scheme
16243 each channel is displayed using the fruit color scheme
16245 each channel is displayed using the cool color scheme
16248 Default value is @samp{channel}.
16251 Specify scale used for calculating intensity color values.
16253 It accepts the following values:
16258 square root, default
16269 Default value is @samp{sqrt}.
16272 Set saturation modifier for displayed colors. Negative values provide
16273 alternative color scheme. @code{0} is no saturation at all.
16274 Saturation must be in [-10.0, 10.0] range.
16275 Default value is @code{1}.
16278 Set window function.
16280 It accepts the following values:
16300 Default value is @code{hann}.
16303 Set orientation of time vs frequency axis. Can be @code{vertical} or
16304 @code{horizontal}. Default is @code{vertical}.
16307 Set ratio of overlap window. Default value is @code{0}.
16308 When value is @code{1} overlap is set to recommended size for specific
16309 window function currently used.
16312 Set scale gain for calculating intensity color values.
16313 Default value is @code{1}.
16316 Set which data to display. Can be @code{magnitude}, default or @code{phase}.
16319 The usage is very similar to the showwaves filter; see the examples in that
16322 @subsection Examples
16326 Large window with logarithmic color scaling:
16328 showspectrum=s=1280x480:scale=log
16332 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
16334 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
16335 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
16339 @section showspectrumpic
16341 Convert input audio to a single video frame, representing the audio frequency
16344 The filter accepts the following options:
16348 Specify the video size for the output. For the syntax of this option, check the
16349 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16350 Default value is @code{4096x2048}.
16353 Specify display mode.
16355 It accepts the following values:
16358 all channels are displayed in the same row
16360 all channels are displayed in separate rows
16362 Default value is @samp{combined}.
16365 Specify display color mode.
16367 It accepts the following values:
16370 each channel is displayed in a separate color
16372 each channel is displayed using the same color scheme
16374 each channel is displayed using the rainbow color scheme
16376 each channel is displayed using the moreland color scheme
16378 each channel is displayed using the nebulae color scheme
16380 each channel is displayed using the fire color scheme
16382 each channel is displayed using the fiery color scheme
16384 each channel is displayed using the fruit color scheme
16386 each channel is displayed using the cool color scheme
16388 Default value is @samp{intensity}.
16391 Specify scale used for calculating intensity color values.
16393 It accepts the following values:
16398 square root, default
16408 Default value is @samp{log}.
16411 Set saturation modifier for displayed colors. Negative values provide
16412 alternative color scheme. @code{0} is no saturation at all.
16413 Saturation must be in [-10.0, 10.0] range.
16414 Default value is @code{1}.
16417 Set window function.
16419 It accepts the following values:
16438 Default value is @code{hann}.
16441 Set orientation of time vs frequency axis. Can be @code{vertical} or
16442 @code{horizontal}. Default is @code{vertical}.
16445 Set scale gain for calculating intensity color values.
16446 Default value is @code{1}.
16449 Draw time and frequency axes and legends. Default is enabled.
16452 @subsection Examples
16456 Extract an audio spectrogram of a whole audio track
16457 in a 1024x1024 picture using @command{ffmpeg}:
16459 ffmpeg -i audio.flac -lavfi showspectrumpic=s=1024x1024 spectrogram.png
16463 @section showvolume
16465 Convert input audio volume to a video output.
16467 The filter accepts the following options:
16474 Set border width, allowed range is [0, 5]. Default is 1.
16477 Set channel width, allowed range is [80, 8192]. Default is 400.
16480 Set channel height, allowed range is [1, 900]. Default is 20.
16483 Set fade, allowed range is [0.001, 1]. Default is 0.95.
16486 Set volume color expression.
16488 The expression can use the following variables:
16492 Current max volume of channel in dB.
16495 Current channel number, starting from 0.
16499 If set, displays channel names. Default is enabled.
16502 If set, displays volume values. Default is enabled.
16505 Set orientation, can be @code{horizontal} or @code{vertical},
16506 default is @code{horizontal}.
16509 Set step size, allowed range s [0, 5]. Default is 0, which means
16515 Convert input audio to a video output, representing the samples waves.
16517 The filter accepts the following options:
16521 Specify the video size for the output. For the syntax of this option, check the
16522 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16523 Default value is @code{600x240}.
16528 Available values are:
16531 Draw a point for each sample.
16534 Draw a vertical line for each sample.
16537 Draw a point for each sample and a line between them.
16540 Draw a centered vertical line for each sample.
16543 Default value is @code{point}.
16546 Set the number of samples which are printed on the same column. A
16547 larger value will decrease the frame rate. Must be a positive
16548 integer. This option can be set only if the value for @var{rate}
16549 is not explicitly specified.
16552 Set the (approximate) output frame rate. This is done by setting the
16553 option @var{n}. Default value is "25".
16555 @item split_channels
16556 Set if channels should be drawn separately or overlap. Default value is 0.
16559 Set colors separated by '|' which are going to be used for drawing of each channel.
16562 Set amplitude scale. Can be linear @code{lin} or logarithmic @code{log}.
16567 @subsection Examples
16571 Output the input file audio and the corresponding video representation
16574 amovie=a.mp3,asplit[out0],showwaves[out1]
16578 Create a synthetic signal and show it with showwaves, forcing a
16579 frame rate of 30 frames per second:
16581 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
16585 @section showwavespic
16587 Convert input audio to a single video frame, representing the samples waves.
16589 The filter accepts the following options:
16593 Specify the video size for the output. For the syntax of this option, check the
16594 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
16595 Default value is @code{600x240}.
16597 @item split_channels
16598 Set if channels should be drawn separately or overlap. Default value is 0.
16601 Set colors separated by '|' which are going to be used for drawing of each channel.
16604 Set amplitude scale. Can be linear @code{lin} or logarithmic @code{log}.
16608 @subsection Examples
16612 Extract a channel split representation of the wave form of a whole audio track
16613 in a 1024x800 picture using @command{ffmpeg}:
16615 ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png
16619 Colorize the waveform with colorchannelmixer. This example will make
16620 the waveform a green color approximately RGB(66,217,150). Additional
16621 channels will be shades of this color.
16623 ffmpeg -i audio.mp3 -filter_complex "showwavespic,colorchannelmixer=rr=66/255:gg=217/255:bb=150/255" waveform.png
16627 @section spectrumsynth
16629 Sythesize audio from 2 input video spectrums, first input stream represents
16630 magnitude across time and second represents phase across time.
16631 The filter will transform from frequency domain as displayed in videos back
16632 to time domain as presented in audio output.
16634 This filter is primarly created for reversing processed @ref{showspectrum}
16635 filter outputs, but can synthesize sound from other spectrograms too.
16636 But in such case results are going to be poor if the phase data is not
16637 available, because in such cases phase data need to be recreated, usually
16638 its just recreated from random noise.
16639 For best results use gray only output (@code{channel} color mode in
16640 @ref{showspectrum} filter) and @code{log} scale for magnitude video and
16641 @code{lin} scale for phase video. To produce phase, for 2nd video, use
16642 @code{data} option. Inputs videos should generally use @code{fullframe}
16643 slide mode as that saves resources needed for decoding video.
16645 The filter accepts the following options:
16649 Specify sample rate of output audio, the sample rate of audio from which
16650 spectrum was generated may differ.
16653 Set number of channels represented in input video spectrums.
16656 Set scale which was used when generating magnitude input spectrum.
16657 Can be @code{lin} or @code{log}. Default is @code{log}.
16660 Set slide which was used when generating inputs spectrums.
16661 Can be @code{replace}, @code{scroll}, @code{fullframe} or @code{rscroll}.
16662 Default is @code{fullframe}.
16665 Set window function used for resynthesis.
16668 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
16669 which means optimal overlap for selected window function will be picked.
16672 Set orientation of input videos. Can be @code{vertical} or @code{horizontal}.
16673 Default is @code{vertical}.
16676 @subsection Examples
16680 First create magnitude and phase videos from audio, assuming audio is stereo with 44100 sample rate,
16681 then resynthesize videos back to audio with spectrumsynth:
16683 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
16684 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
16685 ffmpeg -i magnitude.nut -i phase.nut -lavfi spectrumsynth=channels=2:sample_rate=44100:win_func=hann:overlap=0.875:slide=fullframe output.flac
16689 @section split, asplit
16691 Split input into several identical outputs.
16693 @code{asplit} works with audio input, @code{split} with video.
16695 The filter accepts a single parameter which specifies the number of outputs. If
16696 unspecified, it defaults to 2.
16698 @subsection Examples
16702 Create two separate outputs from the same input:
16704 [in] split [out0][out1]
16708 To create 3 or more outputs, you need to specify the number of
16711 [in] asplit=3 [out0][out1][out2]
16715 Create two separate outputs from the same input, one cropped and
16718 [in] split [splitout1][splitout2];
16719 [splitout1] crop=100:100:0:0 [cropout];
16720 [splitout2] pad=200:200:100:100 [padout];
16724 Create 5 copies of the input audio with @command{ffmpeg}:
16726 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
16732 Receive commands sent through a libzmq client, and forward them to
16733 filters in the filtergraph.
16735 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
16736 must be inserted between two video filters, @code{azmq} between two
16739 To enable these filters you need to install the libzmq library and
16740 headers and configure FFmpeg with @code{--enable-libzmq}.
16742 For more information about libzmq see:
16743 @url{http://www.zeromq.org/}
16745 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
16746 receives messages sent through a network interface defined by the
16747 @option{bind_address} option.
16749 The received message must be in the form:
16751 @var{TARGET} @var{COMMAND} [@var{ARG}]
16754 @var{TARGET} specifies the target of the command, usually the name of
16755 the filter class or a specific filter instance name.
16757 @var{COMMAND} specifies the name of the command for the target filter.
16759 @var{ARG} is optional and specifies the optional argument list for the
16760 given @var{COMMAND}.
16762 Upon reception, the message is processed and the corresponding command
16763 is injected into the filtergraph. Depending on the result, the filter
16764 will send a reply to the client, adopting the format:
16766 @var{ERROR_CODE} @var{ERROR_REASON}
16770 @var{MESSAGE} is optional.
16772 @subsection Examples
16774 Look at @file{tools/zmqsend} for an example of a zmq client which can
16775 be used to send commands processed by these filters.
16777 Consider the following filtergraph generated by @command{ffplay}
16779 ffplay -dumpgraph 1 -f lavfi "
16780 color=s=100x100:c=red [l];
16781 color=s=100x100:c=blue [r];
16782 nullsrc=s=200x100, zmq [bg];
16783 [bg][l] overlay [bg+l];
16784 [bg+l][r] overlay=x=100 "
16787 To change the color of the left side of the video, the following
16788 command can be used:
16790 echo Parsed_color_0 c yellow | tools/zmqsend
16793 To change the right side:
16795 echo Parsed_color_1 c pink | tools/zmqsend
16798 @c man end MULTIMEDIA FILTERS
16800 @chapter Multimedia Sources
16801 @c man begin MULTIMEDIA SOURCES
16803 Below is a description of the currently available multimedia sources.
16807 This is the same as @ref{movie} source, except it selects an audio
16813 Read audio and/or video stream(s) from a movie container.
16815 It accepts the following parameters:
16819 The name of the resource to read (not necessarily a file; it can also be a
16820 device or a stream accessed through some protocol).
16822 @item format_name, f
16823 Specifies the format assumed for the movie to read, and can be either
16824 the name of a container or an input device. If not specified, the
16825 format is guessed from @var{movie_name} or by probing.
16827 @item seek_point, sp
16828 Specifies the seek point in seconds. The frames will be output
16829 starting from this seek point. The parameter is evaluated with
16830 @code{av_strtod}, so the numerical value may be suffixed by an IS
16831 postfix. The default value is "0".
16834 Specifies the streams to read. Several streams can be specified,
16835 separated by "+". The source will then have as many outputs, in the
16836 same order. The syntax is explained in the ``Stream specifiers''
16837 section in the ffmpeg manual. Two special names, "dv" and "da" specify
16838 respectively the default (best suited) video and audio stream. Default
16839 is "dv", or "da" if the filter is called as "amovie".
16841 @item stream_index, si
16842 Specifies the index of the video stream to read. If the value is -1,
16843 the most suitable video stream will be automatically selected. The default
16844 value is "-1". Deprecated. If the filter is called "amovie", it will select
16845 audio instead of video.
16848 Specifies how many times to read the stream in sequence.
16849 If the value is less than 1, the stream will be read again and again.
16850 Default value is "1".
16852 Note that when the movie is looped the source timestamps are not
16853 changed, so it will generate non monotonically increasing timestamps.
16856 It allows overlaying a second video on top of the main input of
16857 a filtergraph, as shown in this graph:
16859 input -----------> deltapts0 --> overlay --> output
16862 movie --> scale--> deltapts1 -------+
16864 @subsection Examples
16868 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
16869 on top of the input labelled "in":
16871 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
16872 [in] setpts=PTS-STARTPTS [main];
16873 [main][over] overlay=16:16 [out]
16877 Read from a video4linux2 device, and overlay it on top of the input
16880 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
16881 [in] setpts=PTS-STARTPTS [main];
16882 [main][over] overlay=16:16 [out]
16886 Read the first video stream and the audio stream with id 0x81 from
16887 dvd.vob; the video is connected to the pad named "video" and the audio is
16888 connected to the pad named "audio":
16890 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
16894 @c man end MULTIMEDIA SOURCES