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
118 recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
119 options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the
120 @code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} functions defined in
121 @file{libavfilter/avfilter.h}.
123 A filterchain consists of a sequence of connected filters, each one
124 connected to the previous one in the sequence. A filterchain is
125 represented by a list of ","-separated filter descriptions.
127 A filtergraph consists of a sequence of filterchains. A sequence of
128 filterchains is represented by a list of ";"-separated filterchain
131 A filter is represented by a string of the form:
132 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
134 @var{filter_name} is the name of the filter class of which the
135 described filter is an instance of, and has to be the name of one of
136 the filter classes registered in the program.
137 The name of the filter class is optionally followed by a string
140 @var{arguments} is a string which contains the parameters used to
141 initialize the filter instance. It may have one of two forms:
145 A ':'-separated list of @var{key=value} pairs.
148 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
149 the option names in the order they are declared. E.g. the @code{fade} filter
150 declares three options in this order -- @option{type}, @option{start_frame} and
151 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
152 @var{in} is assigned to the option @option{type}, @var{0} to
153 @option{start_frame} and @var{30} to @option{nb_frames}.
156 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
157 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
158 follow the same constraints order of the previous point. The following
159 @var{key=value} pairs can be set in any preferred order.
163 If the option value itself is a list of items (e.g. the @code{format} filter
164 takes a list of pixel formats), the items in the list are usually separated by
167 The list of arguments can be quoted using the character "'" as initial
168 and ending mark, and the character '\' for escaping the characters
169 within the quoted text; otherwise the argument string is considered
170 terminated when the next special character (belonging to the set
171 "[]=;,") is encountered.
173 The name and arguments of the filter are optionally preceded and
174 followed by a list of link labels.
175 A link label allows one to name a link and associate it to a filter output
176 or input pad. The preceding labels @var{in_link_1}
177 ... @var{in_link_N}, are associated to the filter input pads,
178 the following labels @var{out_link_1} ... @var{out_link_M}, are
179 associated to the output pads.
181 When two link labels with the same name are found in the
182 filtergraph, a link between the corresponding input and output pad is
185 If an output pad is not labelled, it is linked by default to the first
186 unlabelled input pad of the next filter in the filterchain.
187 For example in the filterchain
189 nullsrc, split[L1], [L2]overlay, nullsink
191 the split filter instance has two output pads, and the overlay filter
192 instance two input pads. The first output pad of split is labelled
193 "L1", the first input pad of overlay is labelled "L2", and the second
194 output pad of split is linked to the second input pad of overlay,
195 which are both unlabelled.
197 In a complete filterchain all the unlabelled filter input and output
198 pads must be connected. A filtergraph is considered valid if all the
199 filter input and output pads of all the filterchains are connected.
201 Libavfilter will automatically insert @ref{scale} filters where format
202 conversion is required. It is possible to specify swscale flags
203 for those automatically inserted scalers by prepending
204 @code{sws_flags=@var{flags};}
205 to the filtergraph description.
207 Here is a BNF description of the filtergraph syntax:
209 @var{NAME} ::= sequence of alphanumeric characters and '_'
210 @var{LINKLABEL} ::= "[" @var{NAME} "]"
211 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
212 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
213 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
214 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
215 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
218 @section Notes on filtergraph escaping
220 Filtergraph description composition entails several levels of
221 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
222 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
223 information about the employed escaping procedure.
225 A first level escaping affects the content of each filter option
226 value, which may contain the special character @code{:} used to
227 separate values, or one of the escaping characters @code{\'}.
229 A second level escaping affects the whole filter description, which
230 may contain the escaping characters @code{\'} or the special
231 characters @code{[],;} used by the filtergraph description.
233 Finally, when you specify a filtergraph on a shell commandline, you
234 need to perform a third level escaping for the shell special
235 characters contained within it.
237 For example, consider the following string to be embedded in
238 the @ref{drawtext} filter description @option{text} value:
240 this is a 'string': may contain one, or more, special characters
243 This string contains the @code{'} special escaping character, and the
244 @code{:} special character, so it needs to be escaped in this way:
246 text=this is a \'string\'\: may contain one, or more, special characters
249 A second level of escaping is required when embedding the filter
250 description in a filtergraph description, in order to escape all the
251 filtergraph special characters. Thus the example above becomes:
253 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
255 (note that in addition to the @code{\'} escaping special characters,
256 also @code{,} needs to be escaped).
258 Finally an additional level of escaping is needed when writing the
259 filtergraph description in a shell command, which depends on the
260 escaping rules of the adopted shell. For example, assuming that
261 @code{\} is special and needs to be escaped with another @code{\}, the
262 previous string will finally result in:
264 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
267 @chapter Timeline editing
269 Some filters support a generic @option{enable} option. For the filters
270 supporting timeline editing, this option can be set to an expression which is
271 evaluated before sending a frame to the filter. If the evaluation is non-zero,
272 the filter will be enabled, otherwise the frame will be sent unchanged to the
273 next filter in the filtergraph.
275 The expression accepts the following values:
278 timestamp expressed in seconds, NAN if the input timestamp is unknown
281 sequential number of the input frame, starting from 0
284 the position in the file of the input frame, NAN if unknown
288 width and height of the input frame if video
291 Additionally, these filters support an @option{enable} command that can be used
292 to re-define the expression.
294 Like any other filtering option, the @option{enable} option follows the same
297 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
298 minutes, and a @ref{curves} filter starting at 3 seconds:
300 smartblur = enable='between(t,10,3*60)',
301 curves = enable='gte(t,3)' : preset=cross_process
304 @c man end FILTERGRAPH DESCRIPTION
306 @chapter Audio Filters
307 @c man begin AUDIO FILTERS
309 When you configure your FFmpeg build, you can disable any of the
310 existing filters using @code{--disable-filters}.
311 The configure output will show the audio filters included in your
314 Below is a description of the currently available audio filters.
318 Delay one or more audio channels.
320 Samples in delayed channel are filled with silence.
322 The filter accepts the following option:
326 Set list of delays in milliseconds for each channel separated by '|'.
327 At least one delay greater than 0 should be provided.
328 Unused delays will be silently ignored. If number of given delays is
329 smaller than number of channels all remaining channels will not be delayed.
336 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
337 the second channel (and any other channels that may be present) unchanged.
345 Apply echoing to the input audio.
347 Echoes are reflected sound and can occur naturally amongst mountains
348 (and sometimes large buildings) when talking or shouting; digital echo
349 effects emulate this behaviour and are often used to help fill out the
350 sound of a single instrument or vocal. The time difference between the
351 original signal and the reflection is the @code{delay}, and the
352 loudness of the reflected signal is the @code{decay}.
353 Multiple echoes can have different delays and decays.
355 A description of the accepted parameters follows.
359 Set input gain of reflected signal. Default is @code{0.6}.
362 Set output gain of reflected signal. Default is @code{0.3}.
365 Set list of time intervals in milliseconds between original signal and reflections
366 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
367 Default is @code{1000}.
370 Set list of loudnesses of reflected signals separated by '|'.
371 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
372 Default is @code{0.5}.
379 Make it sound as if there are twice as many instruments as are actually playing:
381 aecho=0.8:0.88:60:0.4
385 If delay is very short, then it sound like a (metallic) robot playing music:
391 A longer delay will sound like an open air concert in the mountains:
393 aecho=0.8:0.9:1000:0.3
397 Same as above but with one more mountain:
399 aecho=0.8:0.9:1000|1800:0.3|0.25
405 Modify an audio signal according to the specified expressions.
407 This filter accepts one or more expressions (one for each channel),
408 which are evaluated and used to modify a corresponding audio signal.
410 It accepts the following parameters:
414 Set the '|'-separated expressions list for each separate channel. If
415 the number of input channels is greater than the number of
416 expressions, the last specified expression is used for the remaining
419 @item channel_layout, c
420 Set output channel layout. If not specified, the channel layout is
421 specified by the number of expressions. If set to @samp{same}, it will
422 use by default the same input channel layout.
425 Each expression in @var{exprs} can contain the following constants and functions:
429 channel number of the current expression
432 number of the evaluated sample, starting from 0
438 time of the evaluated sample expressed in seconds
441 @item nb_out_channels
442 input and output number of channels
445 the value of input channel with number @var{CH}
448 Note: this filter is slow. For faster processing you should use a
457 aeval=val(ch)/2:c=same
461 Invert phase of the second channel:
469 Apply fade-in/out effect to input audio.
471 A description of the accepted parameters follows.
475 Specify the effect type, can be either @code{in} for fade-in, or
476 @code{out} for a fade-out effect. Default is @code{in}.
478 @item start_sample, ss
479 Specify the number of the start sample for starting to apply the fade
480 effect. Default is 0.
483 Specify the number of samples for which the fade effect has to last. At
484 the end of the fade-in effect the output audio will have the same
485 volume as the input audio, at the end of the fade-out transition
486 the output audio will be silence. Default is 44100.
489 Specify the start time of the fade effect. Default is 0.
490 The value must be specified as a time duration; see
491 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
492 for the accepted syntax.
493 If set this option is used instead of @var{start_sample}.
496 Specify the duration of the fade effect. See
497 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
498 for the accepted syntax.
499 At the end of the fade-in effect the output audio will have the same
500 volume as the input audio, at the end of the fade-out transition
501 the output audio will be silence.
502 By default the duration is determined by @var{nb_samples}.
503 If set this option is used instead of @var{nb_samples}.
506 Set curve for fade transition.
508 It accepts the following values:
511 select triangular, linear slope (default)
513 select quarter of sine wave
515 select half of sine wave
517 select exponential sine wave
521 select inverted parabola
537 Fade in first 15 seconds of audio:
543 Fade out last 25 seconds of a 900 seconds audio:
545 afade=t=out:st=875:d=25
552 Set output format constraints for the input audio. The framework will
553 negotiate the most appropriate format to minimize conversions.
555 It accepts the following parameters:
559 A '|'-separated list of requested sample formats.
562 A '|'-separated list of requested sample rates.
564 @item channel_layouts
565 A '|'-separated list of requested channel layouts.
567 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
568 for the required syntax.
571 If a parameter is omitted, all values are allowed.
573 Force the output to either unsigned 8-bit or signed 16-bit stereo
575 aformat=sample_fmts=u8|s16:channel_layouts=stereo
580 Apply a two-pole all-pass filter with central frequency (in Hz)
581 @var{frequency}, and filter-width @var{width}.
582 An all-pass filter changes the audio's frequency to phase relationship
583 without changing its frequency to amplitude relationship.
585 The filter accepts the following options:
592 Set method to specify band-width of filter.
605 Specify the band-width of a filter in width_type units.
610 Merge two or more audio streams into a single multi-channel stream.
612 The filter accepts the following options:
617 Set the number of inputs. Default is 2.
621 If the channel layouts of the inputs are disjoint, and therefore compatible,
622 the channel layout of the output will be set accordingly and the channels
623 will be reordered as necessary. If the channel layouts of the inputs are not
624 disjoint, the output will have all the channels of the first input then all
625 the channels of the second input, in that order, and the channel layout of
626 the output will be the default value corresponding to the total number of
629 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
630 is FC+BL+BR, then the output will be in 5.1, with the channels in the
631 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
632 first input, b1 is the first channel of the second input).
634 On the other hand, if both input are in stereo, the output channels will be
635 in the default order: a1, a2, b1, b2, and the channel layout will be
636 arbitrarily set to 4.0, which may or may not be the expected value.
638 All inputs must have the same sample rate, and format.
640 If inputs do not have the same duration, the output will stop with the
647 Merge two mono files into a stereo stream:
649 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
653 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
655 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
661 Mixes multiple audio inputs into a single output.
663 Note that this filter only supports float samples (the @var{amerge}
664 and @var{pan} audio filters support many formats). If the @var{amix}
665 input has integer samples then @ref{aresample} will be automatically
666 inserted to perform the conversion to float samples.
670 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
672 will mix 3 input audio streams to a single output with the same duration as the
673 first input and a dropout transition time of 3 seconds.
675 It accepts the following parameters:
679 The number of inputs. If unspecified, it defaults to 2.
682 How to determine the end-of-stream.
686 The duration of the longest input. (default)
689 The duration of the shortest input.
692 The duration of the first input.
696 @item dropout_transition
697 The transition time, in seconds, for volume renormalization when an input
698 stream ends. The default value is 2 seconds.
704 Pass the audio source unchanged to the output.
708 Pad the end of an audio stream with silence.
710 This can be used together with @command{ffmpeg} @option{-shortest} to
711 extend audio streams to the same length as the video stream.
713 A description of the accepted options follows.
717 Set silence packet size. Default value is 4096.
720 Set the number of samples of silence to add to the end. After the
721 value is reached, the stream is terminated. This option is mutually
722 exclusive with @option{whole_len}.
725 Set the minimum total number of samples in the output audio stream. If
726 the value is longer than the input audio length, silence is added to
727 the end, until the value is reached. This option is mutually exclusive
728 with @option{pad_len}.
731 If neither the @option{pad_len} nor the @option{whole_len} option is
732 set, the filter will add silence to the end of the input stream
739 Add 1024 samples of silence to the end of the input:
745 Make sure the audio output will contain at least 10000 samples, pad
746 the input with silence if required:
752 Use @command{ffmpeg} to pad the audio input with silence, so that the
753 video stream will always result the shortest and will be converted
754 until the end in the output file when using the @option{shortest}
757 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
762 Add a phasing effect to the input audio.
764 A phaser filter creates series of peaks and troughs in the frequency spectrum.
765 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
767 A description of the accepted parameters follows.
771 Set input gain. Default is 0.4.
774 Set output gain. Default is 0.74
777 Set delay in milliseconds. Default is 3.0.
780 Set decay. Default is 0.4.
783 Set modulation speed in Hz. Default is 0.5.
786 Set modulation type. Default is triangular.
788 It accepts the following values:
798 Resample the input audio to the specified parameters, using the
799 libswresample library. If none are specified then the filter will
800 automatically convert between its input and output.
802 This filter is also able to stretch/squeeze the audio data to make it match
803 the timestamps or to inject silence / cut out audio to make it match the
804 timestamps, do a combination of both or do neither.
806 The filter accepts the syntax
807 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
808 expresses a sample rate and @var{resampler_options} is a list of
809 @var{key}=@var{value} pairs, separated by ":". See the
810 ffmpeg-resampler manual for the complete list of supported options.
816 Resample the input audio to 44100Hz:
822 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
823 samples per second compensation:
829 @section asetnsamples
831 Set the number of samples per each output audio frame.
833 The last output packet may contain a different number of samples, as
834 the filter will flush all the remaining samples when the input audio
837 The filter accepts the following options:
841 @item nb_out_samples, n
842 Set the number of frames per each output audio frame. The number is
843 intended as the number of samples @emph{per each channel}.
844 Default value is 1024.
847 If set to 1, the filter will pad the last audio frame with zeroes, so
848 that the last frame will contain the same number of samples as the
849 previous ones. Default value is 1.
852 For example, to set the number of per-frame samples to 1234 and
853 disable padding for the last frame, use:
855 asetnsamples=n=1234:p=0
860 Set the sample rate without altering the PCM data.
861 This will result in a change of speed and pitch.
863 The filter accepts the following options:
867 Set the output sample rate. Default is 44100 Hz.
872 Show a line containing various information for each input audio frame.
873 The input audio is not modified.
875 The shown line contains a sequence of key/value pairs of the form
876 @var{key}:@var{value}.
878 The following values are shown in the output:
882 The (sequential) number of the input frame, starting from 0.
885 The presentation timestamp of the input frame, in time base units; the time base
886 depends on the filter input pad, and is usually 1/@var{sample_rate}.
889 The presentation timestamp of the input frame in seconds.
892 position of the frame in the input stream, -1 if this information in
893 unavailable and/or meaningless (for example in case of synthetic audio)
902 The sample rate for the audio frame.
905 The number of samples (per channel) in the frame.
908 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
909 audio, the data is treated as if all the planes were concatenated.
911 @item plane_checksums
912 A list of Adler-32 checksums for each data plane.
917 Display time domain statistical information about the audio channels.
918 Statistics are calculated and displayed for each audio channel and,
919 where applicable, an overall figure is also given.
921 It accepts the following option:
924 Short window length in seconds, used for peak and trough RMS measurement.
925 Default is @code{0.05} (50 milliseconds). Allowed range is @code{[0.1 - 10]}.
928 A description of each shown parameter follows:
932 Mean amplitude displacement from zero.
935 Minimal sample level.
938 Maximal sample level.
942 Standard peak and RMS level measured in dBFS.
946 Peak and trough values for RMS level measured over a short window.
949 Standard ratio of peak to RMS level (note: not in dB).
952 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
953 (i.e. either @var{Min level} or @var{Max level}).
956 Number of occasions (not the number of samples) that the signal attained either
957 @var{Min level} or @var{Max level}.
962 Forward two audio streams and control the order the buffers are forwarded.
964 The filter accepts the following options:
968 Set the expression deciding which stream should be
969 forwarded next: if the result is negative, the first stream is forwarded; if
970 the result is positive or zero, the second stream is forwarded. It can use
971 the following variables:
975 number of buffers forwarded so far on each stream
977 number of samples forwarded so far on each stream
979 current timestamp of each stream
982 The default value is @code{t1-t2}, which means to always forward the stream
983 that has a smaller timestamp.
988 Stress-test @code{amerge} by randomly sending buffers on the wrong
989 input, while avoiding too much of a desynchronization:
991 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
992 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
998 Synchronize audio data with timestamps by squeezing/stretching it and/or
999 dropping samples/adding silence when needed.
1001 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1003 It accepts the following parameters:
1007 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1008 by default. When disabled, time gaps are covered with silence.
1011 The minimum difference between timestamps and audio data (in seconds) to trigger
1012 adding/dropping samples. The default value is 0.1. If you get an imperfect
1013 sync with this filter, try setting this parameter to 0.
1016 The maximum compensation in samples per second. Only relevant with compensate=1.
1017 The default value is 500.
1020 Assume that the first PTS should be this value. The time base is 1 / sample
1021 rate. This allows for padding/trimming at the start of the stream. By default,
1022 no assumption is made about the first frame's expected PTS, so no padding or
1023 trimming is done. For example, this could be set to 0 to pad the beginning with
1024 silence if an audio stream starts after the video stream or to trim any samples
1025 with a negative PTS due to encoder delay.
1033 The filter accepts exactly one parameter, the audio tempo. If not
1034 specified then the filter will assume nominal 1.0 tempo. Tempo must
1035 be in the [0.5, 2.0] range.
1037 @subsection Examples
1041 Slow down audio to 80% tempo:
1047 To speed up audio to 125% tempo:
1055 Trim the input so that the output contains one continuous subpart of the input.
1057 It accepts the following parameters:
1060 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1061 sample with the timestamp @var{start} will be the first sample in the output.
1064 Specify time of the first audio sample that will be dropped, i.e. the
1065 audio sample immediately preceding the one with the timestamp @var{end} will be
1066 the last sample in the output.
1069 Same as @var{start}, except this option sets the start timestamp in samples
1073 Same as @var{end}, except this option sets the end timestamp in samples instead
1077 The maximum duration of the output in seconds.
1080 The number of the first sample that should be output.
1083 The number of the first sample that should be dropped.
1086 @option{start}, @option{end}, and @option{duration} are expressed as time
1087 duration specifications; see
1088 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
1090 Note that the first two sets of the start/end options and the @option{duration}
1091 option look at the frame timestamp, while the _sample options simply count the
1092 samples that pass through the filter. So start/end_pts and start/end_sample will
1093 give different results when the timestamps are wrong, inexact or do not start at
1094 zero. Also note that this filter does not modify the timestamps. If you wish
1095 to have the output timestamps start at zero, insert the asetpts filter after the
1098 If multiple start or end options are set, this filter tries to be greedy and
1099 keep all samples that match at least one of the specified constraints. To keep
1100 only the part that matches all the constraints at once, chain multiple atrim
1103 The defaults are such that all the input is kept. So it is possible to set e.g.
1104 just the end values to keep everything before the specified time.
1109 Drop everything except the second minute of input:
1111 ffmpeg -i INPUT -af atrim=60:120
1115 Keep only the first 1000 samples:
1117 ffmpeg -i INPUT -af atrim=end_sample=1000
1124 Apply a two-pole Butterworth band-pass filter with central
1125 frequency @var{frequency}, and (3dB-point) band-width width.
1126 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1127 instead of the default: constant 0dB peak gain.
1128 The filter roll off at 6dB per octave (20dB per decade).
1130 The filter accepts the following options:
1134 Set the filter's central frequency. Default is @code{3000}.
1137 Constant skirt gain if set to 1. Defaults to 0.
1140 Set method to specify band-width of filter.
1153 Specify the band-width of a filter in width_type units.
1158 Apply a two-pole Butterworth band-reject filter with central
1159 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1160 The filter roll off at 6dB per octave (20dB per decade).
1162 The filter accepts the following options:
1166 Set the filter's central frequency. Default is @code{3000}.
1169 Set method to specify band-width of filter.
1182 Specify the band-width of a filter in width_type units.
1187 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1188 shelving filter with a response similar to that of a standard
1189 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1191 The filter accepts the following options:
1195 Give the gain at 0 Hz. Its useful range is about -20
1196 (for a large cut) to +20 (for a large boost).
1197 Beware of clipping when using a positive gain.
1200 Set the filter's central frequency and so can be used
1201 to extend or reduce the frequency range to be boosted or cut.
1202 The default value is @code{100} Hz.
1205 Set method to specify band-width of filter.
1218 Determine how steep is the filter's shelf transition.
1223 Apply a biquad IIR filter with the given coefficients.
1224 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1225 are the numerator and denominator coefficients respectively.
1228 Bauer stereo to binaural transformation, which improves headphone listening of
1229 stereo audio records.
1231 It accepts the following parameters:
1235 Pre-defined crossfeed level.
1239 Default level (fcut=700, feed=50).
1242 Chu Moy circuit (fcut=700, feed=60).
1245 Jan Meier circuit (fcut=650, feed=95).
1250 Cut frequency (in Hz).
1259 Remap input channels to new locations.
1261 It accepts the following parameters:
1263 @item channel_layout
1264 The channel layout of the output stream.
1267 Map channels from input to output. The argument is a '|'-separated list of
1268 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1269 @var{in_channel} form. @var{in_channel} can be either the name of the input
1270 channel (e.g. FL for front left) or its index in the input channel layout.
1271 @var{out_channel} is the name of the output channel or its index in the output
1272 channel layout. If @var{out_channel} is not given then it is implicitly an
1273 index, starting with zero and increasing by one for each mapping.
1276 If no mapping is present, the filter will implicitly map input channels to
1277 output channels, preserving indices.
1279 For example, assuming a 5.1+downmix input MOV file,
1281 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1283 will create an output WAV file tagged as stereo from the downmix channels of
1286 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1288 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1291 @section channelsplit
1293 Split each channel from an input audio stream into a separate output stream.
1295 It accepts the following parameters:
1297 @item channel_layout
1298 The channel layout of the input stream. The default is "stereo".
1301 For example, assuming a stereo input MP3 file,
1303 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1305 will create an output Matroska file with two audio streams, one containing only
1306 the left channel and the other the right channel.
1308 Split a 5.1 WAV file into per-channel files:
1310 ffmpeg -i in.wav -filter_complex
1311 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1312 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1313 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1318 Compress or expand the audio's dynamic range.
1320 It accepts the following parameters:
1326 A list of times in seconds for each channel over which the instantaneous level
1327 of the input signal is averaged to determine its volume. @var{attacks} refers to
1328 increase of volume and @var{decays} refers to decrease of volume. For most
1329 situations, the attack time (response to the audio getting louder) should be
1330 shorter than the decay time, because the human ear is more sensitive to sudden
1331 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1332 a typical value for decay is 0.8 seconds.
1335 A list of points for the transfer function, specified in dB relative to the
1336 maximum possible signal amplitude. Each key points list must be defined using
1337 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1338 @code{x0/y0 x1/y1 x2/y2 ....}
1340 The input values must be in strictly increasing order but the transfer function
1341 does not have to be monotonically rising. The point @code{0/0} is assumed but
1342 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1343 function are @code{-70/-70|-60/-20}.
1346 Set the curve radius in dB for all joints. It defaults to 0.01.
1349 Set the additional gain in dB to be applied at all points on the transfer
1350 function. This allows for easy adjustment of the overall gain.
1354 Set an initial volume, in dB, to be assumed for each channel when filtering
1355 starts. This permits the user to supply a nominal level initially, so that, for
1356 example, a very large gain is not applied to initial signal levels before the
1357 companding has begun to operate. A typical value for audio which is initially
1358 quiet is -90 dB. It defaults to 0.
1361 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1362 delayed before being fed to the volume adjuster. Specifying a delay
1363 approximately equal to the attack/decay times allows the filter to effectively
1364 operate in predictive rather than reactive mode. It defaults to 0.
1368 @subsection Examples
1372 Make music with both quiet and loud passages suitable for listening to in a
1375 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1379 A noise gate for when the noise is at a lower level than the signal:
1381 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1385 Here is another noise gate, this time for when the noise is at a higher level
1386 than the signal (making it, in some ways, similar to squelch):
1388 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1394 Make audio easier to listen to on headphones.
1396 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1397 so that when listened to on headphones the stereo image is moved from
1398 inside your head (standard for headphones) to outside and in front of
1399 the listener (standard for speakers).
1405 Apply a two-pole peaking equalisation (EQ) filter. With this
1406 filter, the signal-level at and around a selected frequency can
1407 be increased or decreased, whilst (unlike bandpass and bandreject
1408 filters) that at all other frequencies is unchanged.
1410 In order to produce complex equalisation curves, this filter can
1411 be given several times, each with a different central frequency.
1413 The filter accepts the following options:
1417 Set the filter's central frequency in Hz.
1420 Set method to specify band-width of filter.
1433 Specify the band-width of a filter in width_type units.
1436 Set the required gain or attenuation in dB.
1437 Beware of clipping when using a positive gain.
1440 @subsection Examples
1443 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1445 equalizer=f=1000:width_type=h:width=200:g=-10
1449 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1451 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1456 Apply a flanging effect to the audio.
1458 The filter accepts the following options:
1462 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
1465 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
1468 Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
1472 Set percentage of delayed signal mixed with original. Range from 0 to 100.
1473 Default value is 71.
1476 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
1479 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
1480 Default value is @var{sinusoidal}.
1483 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
1484 Default value is 25.
1487 Set delay-line interpolation, @var{linear} or @var{quadratic}.
1488 Default is @var{linear}.
1493 Apply a high-pass filter with 3dB point frequency.
1494 The filter can be either single-pole, or double-pole (the default).
1495 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1497 The filter accepts the following options:
1501 Set frequency in Hz. Default is 3000.
1504 Set number of poles. Default is 2.
1507 Set method to specify band-width of filter.
1520 Specify the band-width of a filter in width_type units.
1521 Applies only to double-pole filter.
1522 The default is 0.707q and gives a Butterworth response.
1527 Join multiple input streams into one multi-channel stream.
1529 It accepts the following parameters:
1533 The number of input streams. It defaults to 2.
1535 @item channel_layout
1536 The desired output channel layout. It defaults to stereo.
1539 Map channels from inputs to output. The argument is a '|'-separated list of
1540 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1541 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1542 can be either the name of the input channel (e.g. FL for front left) or its
1543 index in the specified input stream. @var{out_channel} is the name of the output
1547 The filter will attempt to guess the mappings when they are not specified
1548 explicitly. It does so by first trying to find an unused matching input channel
1549 and if that fails it picks the first unused input channel.
1551 Join 3 inputs (with properly set channel layouts):
1553 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1556 Build a 5.1 output from 6 single-channel streams:
1558 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1559 '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'
1565 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1567 To enable compilation of this filter you need to configure FFmpeg with
1568 @code{--enable-ladspa}.
1572 Specifies the name of LADSPA plugin library to load. If the environment
1573 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1574 each one of the directories specified by the colon separated list in
1575 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1576 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1577 @file{/usr/lib/ladspa/}.
1580 Specifies the plugin within the library. Some libraries contain only
1581 one plugin, but others contain many of them. If this is not set filter
1582 will list all available plugins within the specified library.
1585 Set the '|' separated list of controls which are zero or more floating point
1586 values that determine the behavior of the loaded plugin (for example delay,
1588 Controls need to be defined using the following syntax:
1589 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1590 @var{valuei} is the value set on the @var{i}-th control.
1591 If @option{controls} is set to @code{help}, all available controls and
1592 their valid ranges are printed.
1594 @item sample_rate, s
1595 Specify the sample rate, default to 44100. Only used if plugin have
1599 Set the number of samples per channel per each output frame, default
1600 is 1024. Only used if plugin have zero inputs.
1603 Set the minimum duration of the sourced audio. See
1604 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
1605 for the accepted syntax.
1606 Note that the resulting duration may be greater than the specified duration,
1607 as the generated audio is always cut at the end of a complete frame.
1608 If not specified, or the expressed duration is negative, the audio is
1609 supposed to be generated forever.
1610 Only used if plugin have zero inputs.
1614 @subsection Examples
1618 List all available plugins within amp (LADSPA example plugin) library:
1624 List all available controls and their valid ranges for @code{vcf_notch}
1625 plugin from @code{VCF} library:
1627 ladspa=f=vcf:p=vcf_notch:c=help
1631 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1634 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1638 Add reverberation to the audio using TAP-plugins
1639 (Tom's Audio Processing plugins):
1641 ladspa=file=tap_reverb:tap_reverb
1645 Generate white noise, with 0.2 amplitude:
1647 ladspa=file=cmt:noise_source_white:c=c0=.2
1651 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1652 @code{C* Audio Plugin Suite} (CAPS) library:
1654 ladspa=file=caps:Click:c=c1=20'
1658 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1660 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1664 @subsection Commands
1666 This filter supports the following commands:
1669 Modify the @var{N}-th control value.
1671 If the specified value is not valid, it is ignored and prior one is kept.
1676 Apply a low-pass filter with 3dB point frequency.
1677 The filter can be either single-pole or double-pole (the default).
1678 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1680 The filter accepts the following options:
1684 Set frequency in Hz. Default is 500.
1687 Set number of poles. Default is 2.
1690 Set method to specify band-width of filter.
1703 Specify the band-width of a filter in width_type units.
1704 Applies only to double-pole filter.
1705 The default is 0.707q and gives a Butterworth response.
1710 Mix channels with specific gain levels. The filter accepts the output
1711 channel layout followed by a set of channels definitions.
1713 This filter is also designed to efficiently remap the channels of an audio
1716 The filter accepts parameters of the form:
1717 "@var{l}|@var{outdef}|@var{outdef}|..."
1721 output channel layout or number of channels
1724 output channel specification, of the form:
1725 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1728 output channel to define, either a channel name (FL, FR, etc.) or a channel
1729 number (c0, c1, etc.)
1732 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1735 input channel to use, see out_name for details; it is not possible to mix
1736 named and numbered input channels
1739 If the `=' in a channel specification is replaced by `<', then the gains for
1740 that specification will be renormalized so that the total is 1, thus
1741 avoiding clipping noise.
1743 @subsection Mixing examples
1745 For example, if you want to down-mix from stereo to mono, but with a bigger
1746 factor for the left channel:
1748 pan=1c|c0=0.9*c0+0.1*c1
1751 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1752 7-channels surround:
1754 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1757 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1758 that should be preferred (see "-ac" option) unless you have very specific
1761 @subsection Remapping examples
1763 The channel remapping will be effective if, and only if:
1766 @item gain coefficients are zeroes or ones,
1767 @item only one input per channel output,
1770 If all these conditions are satisfied, the filter will notify the user ("Pure
1771 channel mapping detected"), and use an optimized and lossless method to do the
1774 For example, if you have a 5.1 source and want a stereo audio stream by
1775 dropping the extra channels:
1777 pan="stereo| c0=FL | c1=FR"
1780 Given the same source, you can also switch front left and front right channels
1781 and keep the input channel layout:
1783 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
1786 If the input is a stereo audio stream, you can mute the front left channel (and
1787 still keep the stereo channel layout) with:
1792 Still with a stereo audio stream input, you can copy the right channel in both
1793 front left and right:
1795 pan="stereo| c0=FR | c1=FR"
1800 ReplayGain scanner filter. This filter takes an audio stream as an input and
1801 outputs it unchanged.
1802 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1806 Convert the audio sample format, sample rate and channel layout. It is
1807 not meant to be used directly.
1809 @section silencedetect
1811 Detect silence in an audio stream.
1813 This filter logs a message when it detects that the input audio volume is less
1814 or equal to a noise tolerance value for a duration greater or equal to the
1815 minimum detected noise duration.
1817 The printed times and duration are expressed in seconds.
1819 The filter accepts the following options:
1823 Set silence duration until notification (default is 2 seconds).
1826 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1827 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1830 @subsection Examples
1834 Detect 5 seconds of silence with -50dB noise tolerance:
1836 silencedetect=n=-50dB:d=5
1840 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1841 tolerance in @file{silence.mp3}:
1843 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1847 @section silenceremove
1849 Remove silence from the beginning, middle or end of the audio.
1851 The filter accepts the following options:
1855 This value is used to indicate if audio should be trimmed at beginning of
1856 the audio. A value of zero indicates no silence should be trimmed from the
1857 beginning. When specifying a non-zero value, it trims audio up until it
1858 finds non-silence. Normally, when trimming silence from beginning of audio
1859 the @var{start_periods} will be @code{1} but it can be increased to higher
1860 values to trim all audio up to specific count of non-silence periods.
1861 Default value is @code{0}.
1863 @item start_duration
1864 Specify the amount of time that non-silence must be detected before it stops
1865 trimming audio. By increasing the duration, bursts of noises can be treated
1866 as silence and trimmed off. Default value is @code{0}.
1868 @item start_threshold
1869 This indicates what sample value should be treated as silence. For digital
1870 audio, a value of @code{0} may be fine but for audio recorded from analog,
1871 you may wish to increase the value to account for background noise.
1872 Can be specified in dB (in case "dB" is appended to the specified value)
1873 or amplitude ratio. Default value is @code{0}.
1876 Set the count for trimming silence from the end of audio.
1877 To remove silence from the middle of a file, specify a @var{stop_periods}
1878 that is negative. This value is then treated as a positive value and is
1879 used to indicate the effect should restart processing as specified by
1880 @var{start_periods}, making it suitable for removing periods of silence
1881 in the middle of the audio.
1882 Default value is @code{0}.
1885 Specify a duration of silence that must exist before audio is not copied any
1886 more. By specifying a higher duration, silence that is wanted can be left in
1888 Default value is @code{0}.
1890 @item stop_threshold
1891 This is the same as @option{start_threshold} but for trimming silence from
1893 Can be specified in dB (in case "dB" is appended to the specified value)
1894 or amplitude ratio. Default value is @code{0}.
1897 This indicate that @var{stop_duration} length of audio should be left intact
1898 at the beginning of each period of silence.
1899 For example, if you want to remove long pauses between words but do not want
1900 to remove the pauses completely. Default value is @code{0}.
1904 @subsection Examples
1908 The following example shows how this filter can be used to start a recording
1909 that does not contain the delay at the start which usually occurs between
1910 pressing the record button and the start of the performance:
1912 silenceremove=1:5:0.02
1918 Boost or cut treble (upper) frequencies of the audio using a two-pole
1919 shelving filter with a response similar to that of a standard
1920 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1922 The filter accepts the following options:
1926 Give the gain at whichever is the lower of ~22 kHz and the
1927 Nyquist frequency. Its useful range is about -20 (for a large cut)
1928 to +20 (for a large boost). Beware of clipping when using a positive gain.
1931 Set the filter's central frequency and so can be used
1932 to extend or reduce the frequency range to be boosted or cut.
1933 The default value is @code{3000} Hz.
1936 Set method to specify band-width of filter.
1949 Determine how steep is the filter's shelf transition.
1954 Adjust the input audio volume.
1956 It accepts the following parameters:
1960 Set audio volume expression.
1962 Output values are clipped to the maximum value.
1964 The output audio volume is given by the relation:
1966 @var{output_volume} = @var{volume} * @var{input_volume}
1969 The default value for @var{volume} is "1.0".
1972 This parameter represents the mathematical precision.
1974 It determines which input sample formats will be allowed, which affects the
1975 precision of the volume scaling.
1979 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
1981 32-bit floating-point; this limits input sample format to FLT. (default)
1983 64-bit floating-point; this limits input sample format to DBL.
1987 Choose the behaviour on encountering ReplayGain side data in input frames.
1991 Remove ReplayGain side data, ignoring its contents (the default).
1994 Ignore ReplayGain side data, but leave it in the frame.
1997 Prefer the track gain, if present.
2000 Prefer the album gain, if present.
2003 @item replaygain_preamp
2004 Pre-amplification gain in dB to apply to the selected replaygain gain.
2006 Default value for @var{replaygain_preamp} is 0.0.
2009 Set when the volume expression is evaluated.
2011 It accepts the following values:
2014 only evaluate expression once during the filter initialization, or
2015 when the @samp{volume} command is sent
2018 evaluate expression for each incoming frame
2021 Default value is @samp{once}.
2024 The volume expression can contain the following parameters.
2028 frame number (starting at zero)
2031 @item nb_consumed_samples
2032 number of samples consumed by the filter
2034 number of samples in the current frame
2036 original frame position in the file
2042 PTS at start of stream
2044 time at start of stream
2050 last set volume value
2053 Note that when @option{eval} is set to @samp{once} only the
2054 @var{sample_rate} and @var{tb} variables are available, all other
2055 variables will evaluate to NAN.
2057 @subsection Commands
2059 This filter supports the following commands:
2062 Modify the volume expression.
2063 The command accepts the same syntax of the corresponding option.
2065 If the specified expression is not valid, it is kept at its current
2067 @item replaygain_noclip
2068 Prevent clipping by limiting the gain applied.
2070 Default value for @var{replaygain_noclip} is 1.
2074 @subsection Examples
2078 Halve the input audio volume:
2082 volume=volume=-6.0206dB
2085 In all the above example the named key for @option{volume} can be
2086 omitted, for example like in:
2092 Increase input audio power by 6 decibels using fixed-point precision:
2094 volume=volume=6dB:precision=fixed
2098 Fade volume after time 10 with an annihilation period of 5 seconds:
2100 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
2104 @section volumedetect
2106 Detect the volume of the input video.
2108 The filter has no parameters. The input is not modified. Statistics about
2109 the volume will be printed in the log when the input stream end is reached.
2111 In particular it will show the mean volume (root mean square), maximum
2112 volume (on a per-sample basis), and the beginning of a histogram of the
2113 registered volume values (from the maximum value to a cumulated 1/1000 of
2116 All volumes are in decibels relative to the maximum PCM value.
2118 @subsection Examples
2120 Here is an excerpt of the output:
2122 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2123 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2124 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2125 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2126 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2127 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2128 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2129 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2130 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2136 The mean square energy is approximately -27 dB, or 10^-2.7.
2138 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2140 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2143 In other words, raising the volume by +4 dB does not cause any clipping,
2144 raising it by +5 dB causes clipping for 6 samples, etc.
2146 @c man end AUDIO FILTERS
2148 @chapter Audio Sources
2149 @c man begin AUDIO SOURCES
2151 Below is a description of the currently available audio sources.
2155 Buffer audio frames, and make them available to the filter chain.
2157 This source is mainly intended for a programmatic use, in particular
2158 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2160 It accepts the following parameters:
2164 The timebase which will be used for timestamps of submitted frames. It must be
2165 either a floating-point number or in @var{numerator}/@var{denominator} form.
2168 The sample rate of the incoming audio buffers.
2171 The sample format of the incoming audio buffers.
2172 Either a sample format name or its corresponding integer representation from
2173 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2175 @item channel_layout
2176 The channel layout of the incoming audio buffers.
2177 Either a channel layout name from channel_layout_map in
2178 @file{libavutil/channel_layout.c} or its corresponding integer representation
2179 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2182 The number of channels of the incoming audio buffers.
2183 If both @var{channels} and @var{channel_layout} are specified, then they
2188 @subsection Examples
2191 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2194 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2195 Since the sample format with name "s16p" corresponds to the number
2196 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2199 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2204 Generate an audio signal specified by an expression.
2206 This source accepts in input one or more expressions (one for each
2207 channel), which are evaluated and used to generate a corresponding
2210 This source accepts the following options:
2214 Set the '|'-separated expressions list for each separate channel. In case the
2215 @option{channel_layout} option is not specified, the selected channel layout
2216 depends on the number of provided expressions. Otherwise the last
2217 specified expression is applied to the remaining output channels.
2219 @item channel_layout, c
2220 Set the channel layout. The number of channels in the specified layout
2221 must be equal to the number of specified expressions.
2224 Set the minimum duration of the sourced audio. See
2225 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2226 for the accepted syntax.
2227 Note that the resulting duration may be greater than the specified
2228 duration, as the generated audio is always cut at the end of a
2231 If not specified, or the expressed duration is negative, the audio is
2232 supposed to be generated forever.
2235 Set the number of samples per channel per each output frame,
2238 @item sample_rate, s
2239 Specify the sample rate, default to 44100.
2242 Each expression in @var{exprs} can contain the following constants:
2246 number of the evaluated sample, starting from 0
2249 time of the evaluated sample expressed in seconds, starting from 0
2256 @subsection Examples
2266 Generate a sin signal with frequency of 440 Hz, set sample rate to
2269 aevalsrc="sin(440*2*PI*t):s=8000"
2273 Generate a two channels signal, specify the channel layout (Front
2274 Center + Back Center) explicitly:
2276 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2280 Generate white noise:
2282 aevalsrc="-2+random(0)"
2286 Generate an amplitude modulated signal:
2288 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2292 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2294 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2301 The null audio source, return unprocessed audio frames. It is mainly useful
2302 as a template and to be employed in analysis / debugging tools, or as
2303 the source for filters which ignore the input data (for example the sox
2306 This source accepts the following options:
2310 @item channel_layout, cl
2312 Specifies the channel layout, and can be either an integer or a string
2313 representing a channel layout. The default value of @var{channel_layout}
2316 Check the channel_layout_map definition in
2317 @file{libavutil/channel_layout.c} for the mapping between strings and
2318 channel layout values.
2320 @item sample_rate, r
2321 Specifies the sample rate, and defaults to 44100.
2324 Set the number of samples per requested frames.
2328 @subsection Examples
2332 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2334 anullsrc=r=48000:cl=4
2338 Do the same operation with a more obvious syntax:
2340 anullsrc=r=48000:cl=mono
2344 All the parameters need to be explicitly defined.
2348 Synthesize a voice utterance using the libflite library.
2350 To enable compilation of this filter you need to configure FFmpeg with
2351 @code{--enable-libflite}.
2353 Note that the flite library is not thread-safe.
2355 The filter accepts the following options:
2360 If set to 1, list the names of the available voices and exit
2361 immediately. Default value is 0.
2364 Set the maximum number of samples per frame. Default value is 512.
2367 Set the filename containing the text to speak.
2370 Set the text to speak.
2373 Set the voice to use for the speech synthesis. Default value is
2374 @code{kal}. See also the @var{list_voices} option.
2377 @subsection Examples
2381 Read from file @file{speech.txt}, and synthesize the text using the
2382 standard flite voice:
2384 flite=textfile=speech.txt
2388 Read the specified text selecting the @code{slt} voice:
2390 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2394 Input text to ffmpeg:
2396 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2400 Make @file{ffplay} speak the specified text, using @code{flite} and
2401 the @code{lavfi} device:
2403 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2407 For more information about libflite, check:
2408 @url{http://www.speech.cs.cmu.edu/flite/}
2412 Generate an audio signal made of a sine wave with amplitude 1/8.
2414 The audio signal is bit-exact.
2416 The filter accepts the following options:
2421 Set the carrier frequency. Default is 440 Hz.
2423 @item beep_factor, b
2424 Enable a periodic beep every second with frequency @var{beep_factor} times
2425 the carrier frequency. Default is 0, meaning the beep is disabled.
2427 @item sample_rate, r
2428 Specify the sample rate, default is 44100.
2431 Specify the duration of the generated audio stream.
2433 @item samples_per_frame
2434 Set the number of samples per output frame, default is 1024.
2437 @subsection Examples
2442 Generate a simple 440 Hz sine wave:
2448 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2452 sine=frequency=220:beep_factor=4:duration=5
2457 @c man end AUDIO SOURCES
2459 @chapter Audio Sinks
2460 @c man begin AUDIO SINKS
2462 Below is a description of the currently available audio sinks.
2464 @section abuffersink
2466 Buffer audio frames, and make them available to the end of filter chain.
2468 This sink is mainly intended for programmatic use, in particular
2469 through the interface defined in @file{libavfilter/buffersink.h}
2470 or the options system.
2472 It accepts a pointer to an AVABufferSinkContext structure, which
2473 defines the incoming buffers' formats, to be passed as the opaque
2474 parameter to @code{avfilter_init_filter} for initialization.
2477 Null audio sink; do absolutely nothing with the input audio. It is
2478 mainly useful as a template and for use in analysis / debugging
2481 @c man end AUDIO SINKS
2483 @chapter Video Filters
2484 @c man begin VIDEO FILTERS
2486 When you configure your FFmpeg build, you can disable any of the
2487 existing filters using @code{--disable-filters}.
2488 The configure output will show the video filters included in your
2491 Below is a description of the currently available video filters.
2493 @section alphaextract
2495 Extract the alpha component from the input as a grayscale video. This
2496 is especially useful with the @var{alphamerge} filter.
2500 Add or replace the alpha component of the primary input with the
2501 grayscale value of a second input. This is intended for use with
2502 @var{alphaextract} to allow the transmission or storage of frame
2503 sequences that have alpha in a format that doesn't support an alpha
2506 For example, to reconstruct full frames from a normal YUV-encoded video
2507 and a separate video created with @var{alphaextract}, you might use:
2509 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2512 Since this filter is designed for reconstruction, it operates on frame
2513 sequences without considering timestamps, and terminates when either
2514 input reaches end of stream. This will cause problems if your encoding
2515 pipeline drops frames. If you're trying to apply an image as an
2516 overlay to a video stream, consider the @var{overlay} filter instead.
2520 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2521 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2522 Substation Alpha) subtitles files.
2524 This filter accepts the following option in addition to the common options from
2525 the @ref{subtitles} filter:
2529 Set the shaping engine
2531 Available values are:
2534 The default libass shaping engine, which is the best available.
2536 Fast, font-agnostic shaper that can do only substitutions
2538 Slower shaper using OpenType for substitutions and positioning
2541 The default is @code{auto}.
2546 Compute the bounding box for the non-black pixels in the input frame
2549 This filter computes the bounding box containing all the pixels with a
2550 luminance value greater than the minimum allowed value.
2551 The parameters describing the bounding box are printed on the filter
2554 The filter accepts the following option:
2558 Set the minimal luminance value. Default is @code{16}.
2561 @section blackdetect
2563 Detect video intervals that are (almost) completely black. Can be
2564 useful to detect chapter transitions, commercials, or invalid
2565 recordings. Output lines contains the time for the start, end and
2566 duration of the detected black interval expressed in seconds.
2568 In order to display the output lines, you need to set the loglevel at
2569 least to the AV_LOG_INFO value.
2571 The filter accepts the following options:
2574 @item black_min_duration, d
2575 Set the minimum detected black duration expressed in seconds. It must
2576 be a non-negative floating point number.
2578 Default value is 2.0.
2580 @item picture_black_ratio_th, pic_th
2581 Set the threshold for considering a picture "black".
2582 Express the minimum value for the ratio:
2584 @var{nb_black_pixels} / @var{nb_pixels}
2587 for which a picture is considered black.
2588 Default value is 0.98.
2590 @item pixel_black_th, pix_th
2591 Set the threshold for considering a pixel "black".
2593 The threshold expresses the maximum pixel luminance value for which a
2594 pixel is considered "black". The provided value is scaled according to
2595 the following equation:
2597 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2600 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2601 the input video format, the range is [0-255] for YUV full-range
2602 formats and [16-235] for YUV non full-range formats.
2604 Default value is 0.10.
2607 The following example sets the maximum pixel threshold to the minimum
2608 value, and detects only black intervals of 2 or more seconds:
2610 blackdetect=d=2:pix_th=0.00
2615 Detect frames that are (almost) completely black. Can be useful to
2616 detect chapter transitions or commercials. Output lines consist of
2617 the frame number of the detected frame, the percentage of blackness,
2618 the position in the file if known or -1 and the timestamp in seconds.
2620 In order to display the output lines, you need to set the loglevel at
2621 least to the AV_LOG_INFO value.
2623 It accepts the following parameters:
2628 The percentage of the pixels that have to be below the threshold; it defaults to
2631 @item threshold, thresh
2632 The threshold below which a pixel value is considered black; it defaults to
2637 @section blend, tblend
2639 Blend two video frames into each other.
2641 The @code{blend} filter takes two input streams and outputs one
2642 stream, the first input is the "top" layer and second input is
2643 "bottom" layer. Output terminates when shortest input terminates.
2645 The @code{tblend} (time blend) filter takes two consecutive frames
2646 from one single stream, and outputs the result obtained by blending
2647 the new frame on top of the old frame.
2649 A description of the accepted options follows.
2657 Set blend mode for specific pixel component or all pixel components in case
2658 of @var{all_mode}. Default value is @code{normal}.
2660 Available values for component modes are:
2694 Set blend opacity for specific pixel component or all pixel components in case
2695 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2702 Set blend expression for specific pixel component or all pixel components in case
2703 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2705 The expressions can use the following variables:
2709 The sequential number of the filtered frame, starting from @code{0}.
2713 the coordinates of the current sample
2717 the width and height of currently filtered plane
2721 Width and height scale depending on the currently filtered plane. It is the
2722 ratio between the corresponding luma plane number of pixels and the current
2723 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2724 @code{0.5,0.5} for chroma planes.
2727 Time of the current frame, expressed in seconds.
2730 Value of pixel component at current location for first video frame (top layer).
2733 Value of pixel component at current location for second video frame (bottom layer).
2737 Force termination when the shortest input terminates. Default is
2738 @code{0}. This option is only defined for the @code{blend} filter.
2741 Continue applying the last bottom frame after the end of the stream. A value of
2742 @code{0} disable the filter after the last frame of the bottom layer is reached.
2743 Default is @code{1}. This option is only defined for the @code{blend} filter.
2746 @subsection Examples
2750 Apply transition from bottom layer to top layer in first 10 seconds:
2752 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2756 Apply 1x1 checkerboard effect:
2758 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2762 Apply uncover left effect:
2764 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2768 Apply uncover down effect:
2770 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2774 Apply uncover up-left effect:
2776 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2780 Display differences between the current and the previous frame:
2782 tblend=all_mode=difference128
2788 Apply a boxblur algorithm to the input video.
2790 It accepts the following parameters:
2794 @item luma_radius, lr
2795 @item luma_power, lp
2796 @item chroma_radius, cr
2797 @item chroma_power, cp
2798 @item alpha_radius, ar
2799 @item alpha_power, ap
2803 A description of the accepted options follows.
2806 @item luma_radius, lr
2807 @item chroma_radius, cr
2808 @item alpha_radius, ar
2809 Set an expression for the box radius in pixels used for blurring the
2810 corresponding input plane.
2812 The radius value must be a non-negative number, and must not be
2813 greater than the value of the expression @code{min(w,h)/2} for the
2814 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2817 Default value for @option{luma_radius} is "2". If not specified,
2818 @option{chroma_radius} and @option{alpha_radius} default to the
2819 corresponding value set for @option{luma_radius}.
2821 The expressions can contain the following constants:
2825 The input width and height in pixels.
2829 The input chroma image width and height in pixels.
2833 The horizontal and vertical chroma subsample values. For example, for the
2834 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
2837 @item luma_power, lp
2838 @item chroma_power, cp
2839 @item alpha_power, ap
2840 Specify how many times the boxblur filter is applied to the
2841 corresponding plane.
2843 Default value for @option{luma_power} is 2. If not specified,
2844 @option{chroma_power} and @option{alpha_power} default to the
2845 corresponding value set for @option{luma_power}.
2847 A value of 0 will disable the effect.
2850 @subsection Examples
2854 Apply a boxblur filter with the luma, chroma, and alpha radii
2857 boxblur=luma_radius=2:luma_power=1
2862 Set the luma radius to 2, and alpha and chroma radius to 0:
2864 boxblur=2:1:cr=0:ar=0
2868 Set the luma and chroma radii to a fraction of the video dimension:
2870 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2876 Visualize information exported by some codecs.
2878 Some codecs can export information through frames using side-data or other
2879 means. For example, some MPEG based codecs export motion vectors through the
2880 @var{export_mvs} flag in the codec @option{flags2} option.
2882 The filter accepts the following option:
2886 Set motion vectors to visualize.
2888 Available flags for @var{mv} are:
2892 forward predicted MVs of P-frames
2894 forward predicted MVs of B-frames
2896 backward predicted MVs of B-frames
2900 @subsection Examples
2904 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
2906 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
2910 @section colorbalance
2911 Modify intensity of primary colors (red, green and blue) of input frames.
2913 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2914 regions for the red-cyan, green-magenta or blue-yellow balance.
2916 A positive adjustment value shifts the balance towards the primary color, a negative
2917 value towards the complementary color.
2919 The filter accepts the following options:
2925 Adjust red, green and blue shadows (darkest pixels).
2930 Adjust red, green and blue midtones (medium pixels).
2935 Adjust red, green and blue highlights (brightest pixels).
2937 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2940 @subsection Examples
2944 Add red color cast to shadows:
2950 @section colorlevels
2952 Adjust video input frames using levels.
2954 The filter accepts the following options:
2961 Adjust red, green, blue and alpha input black point.
2962 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2968 Adjust red, green, blue and alpha input white point.
2969 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
2971 Input levels are used to lighten highlights (bright tones), darken shadows
2972 (dark tones), change the balance of bright and dark tones.
2978 Adjust red, green, blue and alpha output black point.
2979 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
2985 Adjust red, green, blue and alpha output white point.
2986 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
2988 Output levels allows manual selection of a constrained output level range.
2991 @subsection Examples
2995 Make video output darker:
2997 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
3003 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
3007 Make video output lighter:
3009 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
3013 Increase brightness:
3015 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
3019 @section colorchannelmixer
3021 Adjust video input frames by re-mixing color channels.
3023 This filter modifies a color channel by adding the values associated to
3024 the other channels of the same pixels. For example if the value to
3025 modify is red, the output value will be:
3027 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
3030 The filter accepts the following options:
3037 Adjust contribution of input red, green, blue and alpha channels for output red channel.
3038 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
3044 Adjust contribution of input red, green, blue and alpha channels for output green channel.
3045 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
3051 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
3052 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
3058 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
3059 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
3061 Allowed ranges for options are @code{[-2.0, 2.0]}.
3064 @subsection Examples
3068 Convert source to grayscale:
3070 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
3073 Simulate sepia tones:
3075 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
3079 @section colormatrix
3081 Convert color matrix.
3083 The filter accepts the following options:
3088 Specify the source and destination color matrix. Both values must be
3091 The accepted values are:
3107 For example to convert from BT.601 to SMPTE-240M, use the command:
3109 colormatrix=bt601:smpte240m
3114 Copy the input source unchanged to the output. This is mainly useful for
3119 Crop the input video to given dimensions.
3121 It accepts the following parameters:
3125 The width of the output video. It defaults to @code{iw}.
3126 This expression is evaluated only once during the filter
3130 The height of the output video. It defaults to @code{ih}.
3131 This expression is evaluated only once during the filter
3135 The horizontal position, in the input video, of the left edge of the output
3136 video. It defaults to @code{(in_w-out_w)/2}.
3137 This expression is evaluated per-frame.
3140 The vertical position, in the input video, of the top edge of the output video.
3141 It defaults to @code{(in_h-out_h)/2}.
3142 This expression is evaluated per-frame.
3145 If set to 1 will force the output display aspect ratio
3146 to be the same of the input, by changing the output sample aspect
3147 ratio. It defaults to 0.
3150 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
3151 expressions containing the following constants:
3156 The computed values for @var{x} and @var{y}. They are evaluated for
3161 The input width and height.
3165 These are the same as @var{in_w} and @var{in_h}.
3169 The output (cropped) width and height.
3173 These are the same as @var{out_w} and @var{out_h}.
3176 same as @var{iw} / @var{ih}
3179 input sample aspect ratio
3182 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
3186 horizontal and vertical chroma subsample values. For example for the
3187 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3190 The number of the input frame, starting from 0.
3193 the position in the file of the input frame, NAN if unknown
3196 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
3200 The expression for @var{out_w} may depend on the value of @var{out_h},
3201 and the expression for @var{out_h} may depend on @var{out_w}, but they
3202 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
3203 evaluated after @var{out_w} and @var{out_h}.
3205 The @var{x} and @var{y} parameters specify the expressions for the
3206 position of the top-left corner of the output (non-cropped) area. They
3207 are evaluated for each frame. If the evaluated value is not valid, it
3208 is approximated to the nearest valid value.
3210 The expression for @var{x} may depend on @var{y}, and the expression
3211 for @var{y} may depend on @var{x}.
3213 @subsection Examples
3217 Crop area with size 100x100 at position (12,34).
3222 Using named options, the example above becomes:
3224 crop=w=100:h=100:x=12:y=34
3228 Crop the central input area with size 100x100:
3234 Crop the central input area with size 2/3 of the input video:
3236 crop=2/3*in_w:2/3*in_h
3240 Crop the input video central square:
3247 Delimit the rectangle with the top-left corner placed at position
3248 100:100 and the right-bottom corner corresponding to the right-bottom
3249 corner of the input image.
3251 crop=in_w-100:in_h-100:100:100
3255 Crop 10 pixels from the left and right borders, and 20 pixels from
3256 the top and bottom borders
3258 crop=in_w-2*10:in_h-2*20
3262 Keep only the bottom right quarter of the input image:
3264 crop=in_w/2:in_h/2:in_w/2:in_h/2
3268 Crop height for getting Greek harmony:
3270 crop=in_w:1/PHI*in_w
3274 Apply trembling effect:
3276 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)
3280 Apply erratic camera effect depending on timestamp:
3282 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)"
3286 Set x depending on the value of y:
3288 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3294 Auto-detect the crop size.
3296 It calculates the necessary cropping parameters and prints the
3297 recommended parameters via the logging system. The detected dimensions
3298 correspond to the non-black area of the input video.
3300 It accepts the following parameters:
3305 Set higher black value threshold, which can be optionally specified
3306 from nothing (0) to everything (255 for 8bit based formats). An intensity
3307 value greater to the set value is considered non-black. It defaults to 24.
3308 You can also specify a value between 0.0 and 1.0 which will be scaled depending
3309 on the bitdepth of the pixel format.
3312 The value which the width/height should be divisible by. It defaults to
3313 16. The offset is automatically adjusted to center the video. Use 2 to
3314 get only even dimensions (needed for 4:2:2 video). 16 is best when
3315 encoding to most video codecs.
3317 @item reset_count, reset
3318 Set the counter that determines after how many frames cropdetect will
3319 reset the previously detected largest video area and start over to
3320 detect the current optimal crop area. Default value is 0.
3322 This can be useful when channel logos distort the video area. 0
3323 indicates 'never reset', and returns the largest area encountered during
3330 Apply color adjustments using curves.
3332 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3333 component (red, green and blue) has its values defined by @var{N} key points
3334 tied from each other using a smooth curve. The x-axis represents the pixel
3335 values from the input frame, and the y-axis the new pixel values to be set for
3338 By default, a component curve is defined by the two points @var{(0;0)} and
3339 @var{(1;1)}. This creates a straight line where each original pixel value is
3340 "adjusted" to its own value, which means no change to the image.
3342 The filter allows you to redefine these two points and add some more. A new
3343 curve (using a natural cubic spline interpolation) will be define to pass
3344 smoothly through all these new coordinates. The new defined points needs to be
3345 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3346 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3347 the vector spaces, the values will be clipped accordingly.
3349 If there is no key point defined in @code{x=0}, the filter will automatically
3350 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3351 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3353 The filter accepts the following options:
3357 Select one of the available color presets. This option can be used in addition
3358 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3359 options takes priority on the preset values.
3360 Available presets are:
3363 @item color_negative
3366 @item increase_contrast
3368 @item linear_contrast
3369 @item medium_contrast
3371 @item strong_contrast
3374 Default is @code{none}.
3376 Set the master key points. These points will define a second pass mapping. It
3377 is sometimes called a "luminance" or "value" mapping. It can be used with
3378 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3379 post-processing LUT.
3381 Set the key points for the red component.
3383 Set the key points for the green component.
3385 Set the key points for the blue component.
3387 Set the key points for all components (not including master).
3388 Can be used in addition to the other key points component
3389 options. In this case, the unset component(s) will fallback on this
3390 @option{all} setting.
3392 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3395 To avoid some filtergraph syntax conflicts, each key points list need to be
3396 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3398 @subsection Examples
3402 Increase slightly the middle level of blue:
3404 curves=blue='0.5/0.58'
3410 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3412 Here we obtain the following coordinates for each components:
3415 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3417 @code{(0;0) (0.50;0.48) (1;1)}
3419 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3423 The previous example can also be achieved with the associated built-in preset:
3425 curves=preset=vintage
3435 Use a Photoshop preset and redefine the points of the green component:
3437 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3443 Denoise frames using 2D DCT (frequency domain filtering).
3445 This filter is not designed for real time.
3447 The filter accepts the following options:
3451 Set the noise sigma constant.
3453 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3454 coefficient (absolute value) below this threshold with be dropped.
3456 If you need a more advanced filtering, see @option{expr}.
3458 Default is @code{0}.
3461 Set number overlapping pixels for each block. Since the filter can be slow, you
3462 may want to reduce this value, at the cost of a less effective filter and the
3463 risk of various artefacts.
3465 If the overlapping value doesn't allow to process the whole input width or
3466 height, a warning will be displayed and according borders won't be denoised.
3468 Default value is @var{blocksize}-1, which is the best possible setting.
3471 Set the coefficient factor expression.
3473 For each coefficient of a DCT block, this expression will be evaluated as a
3474 multiplier value for the coefficient.
3476 If this is option is set, the @option{sigma} option will be ignored.
3478 The absolute value of the coefficient can be accessed through the @var{c}
3482 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
3483 @var{blocksize}, which is the width and height of the processed blocks.
3485 The default value is @var{3} (8x8) and can be raised to @var{4} for a
3486 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
3487 on the speed processing. Also, a larger block size does not necessarily means a
3491 @subsection Examples
3493 Apply a denoise with a @option{sigma} of @code{4.5}:
3498 The same operation can be achieved using the expression system:
3500 dctdnoiz=e='gte(c, 4.5*3)'
3503 Violent denoise using a block size of @code{16x16}:
3511 Drop duplicated frames at regular intervals.
3513 The filter accepts the following options:
3517 Set the number of frames from which one will be dropped. Setting this to
3518 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3519 Default is @code{5}.
3522 Set the threshold for duplicate detection. If the difference metric for a frame
3523 is less than or equal to this value, then it is declared as duplicate. Default
3527 Set scene change threshold. Default is @code{15}.
3531 Set the size of the x and y-axis blocks used during metric calculations.
3532 Larger blocks give better noise suppression, but also give worse detection of
3533 small movements. Must be a power of two. Default is @code{32}.
3536 Mark main input as a pre-processed input and activate clean source input
3537 stream. This allows the input to be pre-processed with various filters to help
3538 the metrics calculation while keeping the frame selection lossless. When set to
3539 @code{1}, the first stream is for the pre-processed input, and the second
3540 stream is the clean source from where the kept frames are chosen. Default is
3544 Set whether or not chroma is considered in the metric calculations. Default is
3550 Remove judder produced by partially interlaced telecined content.
3552 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3553 source was partially telecined content then the output of @code{pullup,dejudder}
3554 will have a variable frame rate. May change the recorded frame rate of the
3555 container. Aside from that change, this filter will not affect constant frame
3558 The option available in this filter is:
3562 Specify the length of the window over which the judder repeats.
3564 Accepts any integer greater than 1. Useful values are:
3568 If the original was telecined from 24 to 30 fps (Film to NTSC).
3571 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3574 If a mixture of the two.
3577 The default is @samp{4}.
3582 Suppress a TV station logo by a simple interpolation of the surrounding
3583 pixels. Just set a rectangle covering the logo and watch it disappear
3584 (and sometimes something even uglier appear - your mileage may vary).
3586 It accepts the following parameters:
3591 Specify the top left corner coordinates of the logo. They must be
3596 Specify the width and height of the logo to clear. They must be
3600 Specify the thickness of the fuzzy edge of the rectangle (added to
3601 @var{w} and @var{h}). The default value is 4.
3604 When set to 1, a green rectangle is drawn on the screen to simplify
3605 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3606 The default value is 0.
3608 The rectangle is drawn on the outermost pixels which will be (partly)
3609 replaced with interpolated values. The values of the next pixels
3610 immediately outside this rectangle in each direction will be used to
3611 compute the interpolated pixel values inside the rectangle.
3615 @subsection Examples
3619 Set a rectangle covering the area with top left corner coordinates 0,0
3620 and size 100x77, and a band of size 10:
3622 delogo=x=0:y=0:w=100:h=77:band=10
3629 Attempt to fix small changes in horizontal and/or vertical shift. This
3630 filter helps remove camera shake from hand-holding a camera, bumping a
3631 tripod, moving on a vehicle, etc.
3633 The filter accepts the following options:
3641 Specify a rectangular area where to limit the search for motion
3643 If desired the search for motion vectors can be limited to a
3644 rectangular area of the frame defined by its top left corner, width
3645 and height. These parameters have the same meaning as the drawbox
3646 filter which can be used to visualise the position of the bounding
3649 This is useful when simultaneous movement of subjects within the frame
3650 might be confused for camera motion by the motion vector search.
3652 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3653 then the full frame is used. This allows later options to be set
3654 without specifying the bounding box for the motion vector search.
3656 Default - search the whole frame.
3660 Specify the maximum extent of movement in x and y directions in the
3661 range 0-64 pixels. Default 16.
3664 Specify how to generate pixels to fill blanks at the edge of the
3665 frame. Available values are:
3668 Fill zeroes at blank locations
3670 Original image at blank locations
3672 Extruded edge value at blank locations
3674 Mirrored edge at blank locations
3676 Default value is @samp{mirror}.
3679 Specify the blocksize to use for motion search. Range 4-128 pixels,
3683 Specify the contrast threshold for blocks. Only blocks with more than
3684 the specified contrast (difference between darkest and lightest
3685 pixels) will be considered. Range 1-255, default 125.
3688 Specify the search strategy. Available values are:
3691 Set exhaustive search
3693 Set less exhaustive search.
3695 Default value is @samp{exhaustive}.
3698 If set then a detailed log of the motion search is written to the
3702 If set to 1, specify using OpenCL capabilities, only available if
3703 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3709 Draw a colored box on the input image.
3711 It accepts the following parameters:
3716 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3720 The expressions which specify the width and height of the box; if 0 they are interpreted as
3721 the input width and height. It defaults to 0.
3724 Specify the color of the box to write. For the general syntax of this option,
3725 check the "Color" section in the ffmpeg-utils manual. If the special
3726 value @code{invert} is used, the box edge color is the same as the
3727 video with inverted luma.
3730 The expression which sets the thickness of the box edge. Default value is @code{3}.
3732 See below for the list of accepted constants.
3735 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3736 following constants:
3740 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3744 horizontal and vertical chroma subsample values. For example for the
3745 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3749 The input width and height.
3752 The input sample aspect ratio.
3756 The x and y offset coordinates where the box is drawn.
3760 The width and height of the drawn box.
3763 The thickness of the drawn box.
3765 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3766 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3770 @subsection Examples
3774 Draw a black box around the edge of the input image:
3780 Draw a box with color red and an opacity of 50%:
3782 drawbox=10:20:200:60:red@@0.5
3785 The previous example can be specified as:
3787 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3791 Fill the box with pink color:
3793 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3797 Draw a 2-pixel red 2.40:1 mask:
3799 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
3805 Draw a grid on the input image.
3807 It accepts the following parameters:
3812 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3816 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3817 input width and height, respectively, minus @code{thickness}, so image gets
3818 framed. Default to 0.
3821 Specify the color of the grid. For the general syntax of this option,
3822 check the "Color" section in the ffmpeg-utils manual. If the special
3823 value @code{invert} is used, the grid color is the same as the
3824 video with inverted luma.
3827 The expression which sets the thickness of the grid line. Default value is @code{1}.
3829 See below for the list of accepted constants.
3832 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3833 following constants:
3837 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3841 horizontal and vertical chroma subsample values. For example for the
3842 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3846 The input grid cell width and height.
3849 The input sample aspect ratio.
3853 The x and y coordinates of some point of grid intersection (meant to configure offset).
3857 The width and height of the drawn cell.
3860 The thickness of the drawn cell.
3862 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3863 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3867 @subsection Examples
3871 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3873 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3877 Draw a white 3x3 grid with an opacity of 50%:
3879 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3886 Draw a text string or text from a specified file on top of a video, using the
3887 libfreetype library.
3889 To enable compilation of this filter, you need to configure FFmpeg with
3890 @code{--enable-libfreetype}.
3891 To enable default font fallback and the @var{font} option you need to
3892 configure FFmpeg with @code{--enable-libfontconfig}.
3893 To enable the @var{text_shaping} option, you need to configure FFmpeg with
3894 @code{--enable-libfribidi}.
3898 It accepts the following parameters:
3903 Used to draw a box around text using the background color.
3904 The value must be either 1 (enable) or 0 (disable).
3905 The default value of @var{box} is 0.
3908 The color to be used for drawing box around text. For the syntax of this
3909 option, check the "Color" section in the ffmpeg-utils manual.
3911 The default value of @var{boxcolor} is "white".
3914 Set the width of the border to be drawn around the text using @var{bordercolor}.
3915 The default value of @var{borderw} is 0.
3918 Set the color to be used for drawing border around text. For the syntax of this
3919 option, check the "Color" section in the ffmpeg-utils manual.
3921 The default value of @var{bordercolor} is "black".
3924 Select how the @var{text} is expanded. Can be either @code{none},
3925 @code{strftime} (deprecated) or
3926 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3930 If true, check and fix text coords to avoid clipping.
3933 The color to be used for drawing fonts. For the syntax of this option, check
3934 the "Color" section in the ffmpeg-utils manual.
3936 The default value of @var{fontcolor} is "black".
3938 @item fontcolor_expr
3939 String which is expanded the same way as @var{text} to obtain dynamic
3940 @var{fontcolor} value. By default this option has empty value and is not
3941 processed. When this option is set, it overrides @var{fontcolor} option.
3944 The font family to be used for drawing text. By default Sans.
3947 The font file to be used for drawing text. The path must be included.
3948 This parameter is mandatory if the fontconfig support is disabled.
3951 The font size to be used for drawing text.
3952 The default value of @var{fontsize} is 16.
3955 If set to 1, attempt to shape the text (for example, reverse the order of
3956 right-to-left text and join Arabic characters) before drawing it.
3957 Otherwise, just draw the text exactly as given.
3958 By default 1 (if supported).
3961 The flags to be used for loading the fonts.
3963 The flags map the corresponding flags supported by libfreetype, and are
3964 a combination of the following values:
3971 @item vertical_layout
3972 @item force_autohint
3975 @item ignore_global_advance_width
3977 @item ignore_transform
3983 Default value is "default".
3985 For more information consult the documentation for the FT_LOAD_*
3989 The color to be used for drawing a shadow behind the drawn text. For the
3990 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3992 The default value of @var{shadowcolor} is "black".
3996 The x and y offsets for the text shadow position with respect to the
3997 position of the text. They can be either positive or negative
3998 values. The default value for both is "0".
4001 The starting frame number for the n/frame_num variable. The default value
4005 The size in number of spaces to use for rendering the tab.
4009 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
4010 format. It can be used with or without text parameter. @var{timecode_rate}
4011 option must be specified.
4013 @item timecode_rate, rate, r
4014 Set the timecode frame rate (timecode only).
4017 The text string to be drawn. The text must be a sequence of UTF-8
4019 This parameter is mandatory if no file is specified with the parameter
4023 A text file containing text to be drawn. The text must be a sequence
4024 of UTF-8 encoded characters.
4026 This parameter is mandatory if no text string is specified with the
4027 parameter @var{text}.
4029 If both @var{text} and @var{textfile} are specified, an error is thrown.
4032 If set to 1, the @var{textfile} will be reloaded before each frame.
4033 Be sure to update it atomically, or it may be read partially, or even fail.
4037 The expressions which specify the offsets where text will be drawn
4038 within the video frame. They are relative to the top/left border of the
4041 The default value of @var{x} and @var{y} is "0".
4043 See below for the list of accepted constants and functions.
4046 The parameters for @var{x} and @var{y} are expressions containing the
4047 following constants and functions:
4051 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
4055 horizontal and vertical chroma subsample values. For example for the
4056 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4059 the height of each text line
4067 @item max_glyph_a, ascent
4068 the maximum distance from the baseline to the highest/upper grid
4069 coordinate used to place a glyph outline point, for all the rendered
4071 It is a positive value, due to the grid's orientation with the Y axis
4074 @item max_glyph_d, descent
4075 the maximum distance from the baseline to the lowest grid coordinate
4076 used to place a glyph outline point, for all the rendered glyphs.
4077 This is a negative value, due to the grid's orientation, with the Y axis
4081 maximum glyph height, that is the maximum height for all the glyphs
4082 contained in the rendered text, it is equivalent to @var{ascent} -
4086 maximum glyph width, that is the maximum width for all the glyphs
4087 contained in the rendered text
4090 the number of input frame, starting from 0
4092 @item rand(min, max)
4093 return a random number included between @var{min} and @var{max}
4096 The input sample aspect ratio.
4099 timestamp expressed in seconds, NAN if the input timestamp is unknown
4102 the height of the rendered text
4105 the width of the rendered text
4109 the x and y offset coordinates where the text is drawn.
4111 These parameters allow the @var{x} and @var{y} expressions to refer
4112 each other, so you can for example specify @code{y=x/dar}.
4115 @anchor{drawtext_expansion}
4116 @subsection Text expansion
4118 If @option{expansion} is set to @code{strftime},
4119 the filter recognizes strftime() sequences in the provided text and
4120 expands them accordingly. Check the documentation of strftime(). This
4121 feature is deprecated.
4123 If @option{expansion} is set to @code{none}, the text is printed verbatim.
4125 If @option{expansion} is set to @code{normal} (which is the default),
4126 the following expansion mechanism is used.
4128 The backslash character '\', followed by any character, always expands to
4129 the second character.
4131 Sequence of the form @code{%@{...@}} are expanded. The text between the
4132 braces is a function name, possibly followed by arguments separated by ':'.
4133 If the arguments contain special characters or delimiters (':' or '@}'),
4134 they should be escaped.
4136 Note that they probably must also be escaped as the value for the
4137 @option{text} option in the filter argument string and as the filter
4138 argument in the filtergraph description, and possibly also for the shell,
4139 that makes up to four levels of escaping; using a text file avoids these
4142 The following functions are available:
4147 The expression evaluation result.
4149 It must take one argument specifying the expression to be evaluated,
4150 which accepts the same constants and functions as the @var{x} and
4151 @var{y} values. Note that not all constants should be used, for
4152 example the text size is not known when evaluating the expression, so
4153 the constants @var{text_w} and @var{text_h} will have an undefined
4156 @item expr_int_format, eif
4157 Evaluate the expression's value and output as formatted integer.
4159 The first argument is the expression to be evaluated, just as for the @var{expr} function.
4160 The second argument specifies the output format. Allowed values are 'x', 'X', 'd' and
4161 'u'. They are treated exactly as in the printf function.
4162 The third parameter is optional and sets the number of positions taken by the output.
4163 It can be used to add padding with zeros from the left.
4166 The time at which the filter is running, expressed in UTC.
4167 It can accept an argument: a strftime() format string.
4170 The time at which the filter is running, expressed in the local time zone.
4171 It can accept an argument: a strftime() format string.
4174 Frame metadata. It must take one argument specifying metadata key.
4177 The frame number, starting from 0.
4180 A 1 character description of the current picture type.
4183 The timestamp of the current frame.
4184 It can take up to two arguments.
4186 The first argument is the format of the timestamp; it defaults to @code{flt}
4187 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
4188 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
4190 The second argument is an offset added to the timestamp.
4194 @subsection Examples
4198 Draw "Test Text" with font FreeSerif, using the default values for the
4199 optional parameters.
4202 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
4206 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
4207 and y=50 (counting from the top-left corner of the screen), text is
4208 yellow with a red box around it. Both the text and the box have an
4212 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
4213 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
4216 Note that the double quotes are not necessary if spaces are not used
4217 within the parameter list.
4220 Show the text at the center of the video frame:
4222 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
4226 Show a text line sliding from right to left in the last row of the video
4227 frame. The file @file{LONG_LINE} is assumed to contain a single line
4230 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
4234 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
4236 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
4240 Draw a single green letter "g", at the center of the input video.
4241 The glyph baseline is placed at half screen height.
4243 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
4247 Show text for 1 second every 3 seconds:
4249 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
4253 Use fontconfig to set the font. Note that the colons need to be escaped.
4255 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
4259 Print the date of a real-time encoding (see strftime(3)):
4261 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
4265 Show text fading in and out (appearing/disappearing):
4268 DS=1.0 # display start
4269 DE=10.0 # display end
4270 FID=1.5 # fade in duration
4271 FOD=5 # fade out duration
4272 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 @}"
4277 For more information about libfreetype, check:
4278 @url{http://www.freetype.org/}.
4280 For more information about fontconfig, check:
4281 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
4283 For more information about libfribidi, check:
4284 @url{http://fribidi.org/}.
4288 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
4290 The filter accepts the following options:
4295 Set low and high threshold values used by the Canny thresholding
4298 The high threshold selects the "strong" edge pixels, which are then
4299 connected through 8-connectivity with the "weak" edge pixels selected
4300 by the low threshold.
4302 @var{low} and @var{high} threshold values must be chosen in the range
4303 [0,1], and @var{low} should be lesser or equal to @var{high}.
4305 Default value for @var{low} is @code{20/255}, and default value for @var{high}
4309 Define the drawing mode.
4313 Draw white/gray wires on black background.
4316 Mix the colors to create a paint/cartoon effect.
4319 Default value is @var{wires}.
4322 @subsection Examples
4326 Standard edge detection with custom values for the hysteresis thresholding:
4328 edgedetect=low=0.1:high=0.4
4332 Painting effect without thresholding:
4334 edgedetect=mode=colormix:high=0
4339 Set brightness, contrast, saturation and approximate gamma adjustment.
4341 The filter accepts the following options:
4345 Set the contrast value. It accepts a float value in range @code{-2.0} to
4346 @code{2.0}. The default value is @code{0.0}.
4349 Set the brightness value. It accepts a float value in range @code{-1.0} to
4350 @code{1.0}. The default value is @code{0.0}.
4353 Set the saturation value. It accepts a float value in range @code{0.0} to
4354 @code{3.0}. The default value is @code{1.0}.
4357 Set the gamma value. It accepts a float value in range @code{0.1} to @code{10.0}.
4358 The default value is @code{1.0}.
4361 Set the gamma value for red. It accepts a float value in range
4362 @code{0.1} to @code{10.0}. The default value is @code{1.0}.
4365 Set the gamma value for green. It accepts a float value in range
4366 @code{0.1} to @code{10.0}. The default value is @code{1.0}.
4369 Set the gamma value for blue. It accepts a float value in range
4370 @code{0.1} to @code{10.0}. The default value is @code{1.0}.
4373 Can be used to reduce the effect of a high gamma value on bright image areas,
4374 e.g. keep them from getting overamplified and just plain white. It accepts a
4375 float value in range @code{0.0} to @code{1.0}.A value of @code{0.0} turns the
4376 gamma correction all the way down while @code{1.0} leaves it at its full strength.
4377 Default is @code{1.0}.
4381 @section extractplanes
4383 Extract color channel components from input video stream into
4384 separate grayscale video streams.
4386 The filter accepts the following option:
4390 Set plane(s) to extract.
4392 Available values for planes are:
4403 Choosing planes not available in the input will result in an error.
4404 That means you cannot select @code{r}, @code{g}, @code{b} planes
4405 with @code{y}, @code{u}, @code{v} planes at same time.
4408 @subsection Examples
4412 Extract luma, u and v color channel component from input video frame
4413 into 3 grayscale outputs:
4415 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
4421 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4423 For each input image, the filter will compute the optimal mapping from
4424 the input to the output given the codebook length, that is the number
4425 of distinct output colors.
4427 This filter accepts the following options.
4430 @item codebook_length, l
4431 Set codebook length. The value must be a positive integer, and
4432 represents the number of distinct output colors. Default value is 256.
4435 Set the maximum number of iterations to apply for computing the optimal
4436 mapping. The higher the value the better the result and the higher the
4437 computation time. Default value is 1.
4440 Set a random seed, must be an integer included between 0 and
4441 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4442 will try to use a good random seed on a best effort basis.
4447 Apply a fade-in/out effect to the input video.
4449 It accepts the following parameters:
4453 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4455 Default is @code{in}.
4457 @item start_frame, s
4458 Specify the number of the frame to start applying the fade
4459 effect at. Default is 0.
4462 The number of frames that the fade effect lasts. At the end of the
4463 fade-in effect, the output video will have the same intensity as the input video.
4464 At the end of the fade-out transition, the output video will be filled with the
4465 selected @option{color}.
4469 If set to 1, fade only alpha channel, if one exists on the input.
4472 @item start_time, st
4473 Specify the timestamp (in seconds) of the frame to start to apply the fade
4474 effect. If both start_frame and start_time are specified, the fade will start at
4475 whichever comes last. Default is 0.
4478 The number of seconds for which the fade effect has to last. At the end of the
4479 fade-in effect the output video will have the same intensity as the input video,
4480 at the end of the fade-out transition the output video will be filled with the
4481 selected @option{color}.
4482 If both duration and nb_frames are specified, duration is used. Default is 0.
4485 Specify the color of the fade. Default is "black".
4488 @subsection Examples
4492 Fade in the first 30 frames of video:
4497 The command above is equivalent to:
4503 Fade out the last 45 frames of a 200-frame video:
4506 fade=type=out:start_frame=155:nb_frames=45
4510 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4512 fade=in:0:25, fade=out:975:25
4516 Make the first 5 frames yellow, then fade in from frame 5-24:
4518 fade=in:5:20:color=yellow
4522 Fade in alpha over first 25 frames of video:
4524 fade=in:0:25:alpha=1
4528 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4530 fade=t=in:st=5.5:d=0.5
4537 Extract a single field from an interlaced image using stride
4538 arithmetic to avoid wasting CPU time. The output frames are marked as
4541 The filter accepts the following options:
4545 Specify whether to extract the top (if the value is @code{0} or
4546 @code{top}) or the bottom field (if the value is @code{1} or
4552 Field matching filter for inverse telecine. It is meant to reconstruct the
4553 progressive frames from a telecined stream. The filter does not drop duplicated
4554 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4555 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4557 The separation of the field matching and the decimation is notably motivated by
4558 the possibility of inserting a de-interlacing filter fallback between the two.
4559 If the source has mixed telecined and real interlaced content,
4560 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4561 But these remaining combed frames will be marked as interlaced, and thus can be
4562 de-interlaced by a later filter such as @ref{yadif} before decimation.
4564 In addition to the various configuration options, @code{fieldmatch} can take an
4565 optional second stream, activated through the @option{ppsrc} option. If
4566 enabled, the frames reconstruction will be based on the fields and frames from
4567 this second stream. This allows the first input to be pre-processed in order to
4568 help the various algorithms of the filter, while keeping the output lossless
4569 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4570 or brightness/contrast adjustments can help.
4572 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4573 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4574 which @code{fieldmatch} is based on. While the semantic and usage are very
4575 close, some behaviour and options names can differ.
4577 The @ref{decimate} filter currently only works for constant frame rate input.
4578 Do not use @code{fieldmatch} and @ref{decimate} if your input has mixed
4579 telecined and progressive content with changing framerate.
4581 The filter accepts the following options:
4585 Specify the assumed field order of the input stream. Available values are:
4589 Auto detect parity (use FFmpeg's internal parity value).
4591 Assume bottom field first.
4593 Assume top field first.
4596 Note that it is sometimes recommended not to trust the parity announced by the
4599 Default value is @var{auto}.
4602 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4603 sense that it won't risk creating jerkiness due to duplicate frames when
4604 possible, but if there are bad edits or blended fields it will end up
4605 outputting combed frames when a good match might actually exist. On the other
4606 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4607 but will almost always find a good frame if there is one. The other values are
4608 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4609 jerkiness and creating duplicate frames versus finding good matches in sections
4610 with bad edits, orphaned fields, blended fields, etc.
4612 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4614 Available values are:
4618 2-way matching (p/c)
4620 2-way matching, and trying 3rd match if still combed (p/c + n)
4622 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4624 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4625 still combed (p/c + n + u/b)
4627 3-way matching (p/c/n)
4629 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4630 detected as combed (p/c/n + u/b)
4633 The parenthesis at the end indicate the matches that would be used for that
4634 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4637 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4640 Default value is @var{pc_n}.
4643 Mark the main input stream as a pre-processed input, and enable the secondary
4644 input stream as the clean source to pick the fields from. See the filter
4645 introduction for more details. It is similar to the @option{clip2} feature from
4648 Default value is @code{0} (disabled).
4651 Set the field to match from. It is recommended to set this to the same value as
4652 @option{order} unless you experience matching failures with that setting. In
4653 certain circumstances changing the field that is used to match from can have a
4654 large impact on matching performance. Available values are:
4658 Automatic (same value as @option{order}).
4660 Match from the bottom field.
4662 Match from the top field.
4665 Default value is @var{auto}.
4668 Set whether or not chroma is included during the match comparisons. In most
4669 cases it is recommended to leave this enabled. You should set this to @code{0}
4670 only if your clip has bad chroma problems such as heavy rainbowing or other
4671 artifacts. Setting this to @code{0} could also be used to speed things up at
4672 the cost of some accuracy.
4674 Default value is @code{1}.
4678 These define an exclusion band which excludes the lines between @option{y0} and
4679 @option{y1} from being included in the field matching decision. An exclusion
4680 band can be used to ignore subtitles, a logo, or other things that may
4681 interfere with the matching. @option{y0} sets the starting scan line and
4682 @option{y1} sets the ending line; all lines in between @option{y0} and
4683 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4684 @option{y0} and @option{y1} to the same value will disable the feature.
4685 @option{y0} and @option{y1} defaults to @code{0}.
4688 Set the scene change detection threshold as a percentage of maximum change on
4689 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4690 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4691 @option{scthresh} is @code{[0.0, 100.0]}.
4693 Default value is @code{12.0}.
4696 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4697 account the combed scores of matches when deciding what match to use as the
4698 final match. Available values are:
4702 No final matching based on combed scores.
4704 Combed scores are only used when a scene change is detected.
4706 Use combed scores all the time.
4709 Default is @var{sc}.
4712 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4713 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4714 Available values are:
4718 No forced calculation.
4720 Force p/c/n calculations.
4722 Force p/c/n/u/b calculations.
4725 Default value is @var{none}.
4728 This is the area combing threshold used for combed frame detection. This
4729 essentially controls how "strong" or "visible" combing must be to be detected.
4730 Larger values mean combing must be more visible and smaller values mean combing
4731 can be less visible or strong and still be detected. Valid settings are from
4732 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4733 be detected as combed). This is basically a pixel difference value. A good
4734 range is @code{[8, 12]}.
4736 Default value is @code{9}.
4739 Sets whether or not chroma is considered in the combed frame decision. Only
4740 disable this if your source has chroma problems (rainbowing, etc.) that are
4741 causing problems for the combed frame detection with chroma enabled. Actually,
4742 using @option{chroma}=@var{0} is usually more reliable, except for the case
4743 where there is chroma only combing in the source.
4745 Default value is @code{0}.
4749 Respectively set the x-axis and y-axis size of the window used during combed
4750 frame detection. This has to do with the size of the area in which
4751 @option{combpel} pixels are required to be detected as combed for a frame to be
4752 declared combed. See the @option{combpel} parameter description for more info.
4753 Possible values are any number that is a power of 2 starting at 4 and going up
4756 Default value is @code{16}.
4759 The number of combed pixels inside any of the @option{blocky} by
4760 @option{blockx} size blocks on the frame for the frame to be detected as
4761 combed. While @option{cthresh} controls how "visible" the combing must be, this
4762 setting controls "how much" combing there must be in any localized area (a
4763 window defined by the @option{blockx} and @option{blocky} settings) on the
4764 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4765 which point no frames will ever be detected as combed). This setting is known
4766 as @option{MI} in TFM/VFM vocabulary.
4768 Default value is @code{80}.
4771 @anchor{p/c/n/u/b meaning}
4772 @subsection p/c/n/u/b meaning
4774 @subsubsection p/c/n
4776 We assume the following telecined stream:
4779 Top fields: 1 2 2 3 4
4780 Bottom fields: 1 2 3 4 4
4783 The numbers correspond to the progressive frame the fields relate to. Here, the
4784 first two frames are progressive, the 3rd and 4th are combed, and so on.
4786 When @code{fieldmatch} is configured to run a matching from bottom
4787 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4792 B 1 2 3 4 4 <-- matching reference
4801 As a result of the field matching, we can see that some frames get duplicated.
4802 To perform a complete inverse telecine, you need to rely on a decimation filter
4803 after this operation. See for instance the @ref{decimate} filter.
4805 The same operation now matching from top fields (@option{field}=@var{top})
4810 T 1 2 2 3 4 <-- matching reference
4820 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4821 basically, they refer to the frame and field of the opposite parity:
4824 @item @var{p} matches the field of the opposite parity in the previous frame
4825 @item @var{c} matches the field of the opposite parity in the current frame
4826 @item @var{n} matches the field of the opposite parity in the next frame
4831 The @var{u} and @var{b} matching are a bit special in the sense that they match
4832 from the opposite parity flag. In the following examples, we assume that we are
4833 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4834 'x' is placed above and below each matched fields.
4836 With bottom matching (@option{field}=@var{bottom}):
4841 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4842 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4850 With top matching (@option{field}=@var{top}):
4855 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4856 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4864 @subsection Examples
4866 Simple IVTC of a top field first telecined stream:
4868 fieldmatch=order=tff:combmatch=none, decimate
4871 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4873 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4878 Transform the field order of the input video.
4880 It accepts the following parameters:
4885 The output field order. Valid values are @var{tff} for top field first or @var{bff}
4886 for bottom field first.
4889 The default value is @samp{tff}.
4891 The transformation is done by shifting the picture content up or down
4892 by one line, and filling the remaining line with appropriate picture content.
4893 This method is consistent with most broadcast field order converters.
4895 If the input video is not flagged as being interlaced, or it is already
4896 flagged as being of the required output field order, then this filter does
4897 not alter the incoming video.
4899 It is very useful when converting to or from PAL DV material,
4900 which is bottom field first.
4904 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4909 Buffer input images and send them when they are requested.
4911 It is mainly useful when auto-inserted by the libavfilter
4914 It does not take parameters.
4919 Convert the input video to one of the specified pixel formats.
4920 Libavfilter will try to pick one that is suitable as input to
4923 It accepts the following parameters:
4927 A '|'-separated list of pixel format names, such as
4928 "pix_fmts=yuv420p|monow|rgb24".
4932 @subsection Examples
4936 Convert the input video to the @var{yuv420p} format
4938 format=pix_fmts=yuv420p
4941 Convert the input video to any of the formats in the list
4943 format=pix_fmts=yuv420p|yuv444p|yuv410p
4950 Convert the video to specified constant frame rate by duplicating or dropping
4951 frames as necessary.
4953 It accepts the following parameters:
4957 The desired output frame rate. The default is @code{25}.
4962 Possible values are:
4965 zero round towards 0
4969 round towards -infinity
4971 round towards +infinity
4975 The default is @code{near}.
4978 Assume the first PTS should be the given value, in seconds. This allows for
4979 padding/trimming at the start of stream. By default, no assumption is made
4980 about the first frame's expected PTS, so no padding or trimming is done.
4981 For example, this could be set to 0 to pad the beginning with duplicates of
4982 the first frame if a video stream starts after the audio stream or to trim any
4983 frames with a negative PTS.
4987 Alternatively, the options can be specified as a flat string:
4988 @var{fps}[:@var{round}].
4990 See also the @ref{setpts} filter.
4992 @subsection Examples
4996 A typical usage in order to set the fps to 25:
5002 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
5004 fps=fps=film:round=near
5010 Pack two different video streams into a stereoscopic video, setting proper
5011 metadata on supported codecs. The two views should have the same size and
5012 framerate and processing will stop when the shorter video ends. Please note
5013 that you may conveniently adjust view properties with the @ref{scale} and
5016 It accepts the following parameters:
5020 The desired packing format. Supported values are:
5025 The views are next to each other (default).
5028 The views are on top of each other.
5031 The views are packed by line.
5034 The views are packed by column.
5037 The views are temporally interleaved.
5046 # Convert left and right views into a frame-sequential video
5047 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
5049 # Convert views into a side-by-side video with the same output resolution as the input
5050 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
5055 Select one frame every N-th frame.
5057 This filter accepts the following option:
5060 Select frame after every @code{step} frames.
5061 Allowed values are positive integers higher than 0. Default value is @code{1}.
5067 Apply a frei0r effect to the input video.
5069 To enable the compilation of this filter, you need to install the frei0r
5070 header and configure FFmpeg with @code{--enable-frei0r}.
5072 It accepts the following parameters:
5077 The name of the frei0r effect to load. If the environment variable
5078 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
5079 directories specified by the colon-separated list in @env{FREIOR_PATH}.
5080 Otherwise, the standard frei0r paths are searched, in this order:
5081 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
5082 @file{/usr/lib/frei0r-1/}.
5085 A '|'-separated list of parameters to pass to the frei0r effect.
5089 A frei0r effect parameter can be a boolean (its value is either
5090 "y" or "n"), a double, a color (specified as
5091 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
5092 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
5093 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
5094 @var{X} and @var{Y} are floating point numbers) and/or a string.
5096 The number and types of parameters depend on the loaded effect. If an
5097 effect parameter is not specified, the default value is set.
5099 @subsection Examples
5103 Apply the distort0r effect, setting the first two double parameters:
5105 frei0r=filter_name=distort0r:filter_params=0.5|0.01
5109 Apply the colordistance effect, taking a color as the first parameter:
5111 frei0r=colordistance:0.2/0.3/0.4
5112 frei0r=colordistance:violet
5113 frei0r=colordistance:0x112233
5117 Apply the perspective effect, specifying the top left and top right image
5120 frei0r=perspective:0.2/0.2|0.8/0.2
5124 For more information, see
5125 @url{http://frei0r.dyne.org}
5129 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
5131 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
5132 processing filter, one of them is performed once per block, not per pixel.
5133 This allows for much higher speed.
5135 The filter accepts the following options:
5139 Set quality. This option defines the number of levels for averaging. It accepts
5140 an integer in the range 4-5. Default value is @code{4}.
5143 Force a constant quantization parameter. It accepts an integer in range 0-63.
5144 If not set, the filter will use the QP from the video stream (if available).
5147 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
5148 more details but also more artifacts, while higher values make the image smoother
5149 but also blurrier. Default value is @code{0} − PSNR optimal.
5152 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
5153 option may cause flicker since the B-Frames have often larger QP. Default is
5154 @code{0} (not enabled).
5160 The filter accepts the following options:
5164 Set the luminance expression.
5166 Set the chrominance blue expression.
5168 Set the chrominance red expression.
5170 Set the alpha expression.
5172 Set the red expression.
5174 Set the green expression.
5176 Set the blue expression.
5179 The colorspace is selected according to the specified options. If one
5180 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
5181 options is specified, the filter will automatically select a YCbCr
5182 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
5183 @option{blue_expr} options is specified, it will select an RGB
5186 If one of the chrominance expression is not defined, it falls back on the other
5187 one. If no alpha expression is specified it will evaluate to opaque value.
5188 If none of chrominance expressions are specified, they will evaluate
5189 to the luminance expression.
5191 The expressions can use the following variables and functions:
5195 The sequential number of the filtered frame, starting from @code{0}.
5199 The coordinates of the current sample.
5203 The width and height of the image.
5207 Width and height scale depending on the currently filtered plane. It is the
5208 ratio between the corresponding luma plane number of pixels and the current
5209 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
5210 @code{0.5,0.5} for chroma planes.
5213 Time of the current frame, expressed in seconds.
5216 Return the value of the pixel at location (@var{x},@var{y}) of the current
5220 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
5224 Return the value of the pixel at location (@var{x},@var{y}) of the
5225 blue-difference chroma plane. Return 0 if there is no such plane.
5228 Return the value of the pixel at location (@var{x},@var{y}) of the
5229 red-difference chroma plane. Return 0 if there is no such plane.
5234 Return the value of the pixel at location (@var{x},@var{y}) of the
5235 red/green/blue component. Return 0 if there is no such component.
5238 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
5239 plane. Return 0 if there is no such plane.
5242 For functions, if @var{x} and @var{y} are outside the area, the value will be
5243 automatically clipped to the closer edge.
5245 @subsection Examples
5249 Flip the image horizontally:
5255 Generate a bidimensional sine wave, with angle @code{PI/3} and a
5256 wavelength of 100 pixels:
5258 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
5262 Generate a fancy enigmatic moving light:
5264 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
5268 Generate a quick emboss effect:
5270 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
5274 Modify RGB components depending on pixel position:
5276 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
5280 Create a radial gradient that is the same size as the input (also see
5281 the @ref{vignette} filter):
5283 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
5287 Create a linear gradient to use as a mask for another filter, then
5288 compose with @ref{overlay}. In this example the video will gradually
5289 become more blurry from the top to the bottom of the y-axis as defined
5290 by the linear gradient:
5292 ffmpeg -i input.mp4 -filter_complex "geq=lum=255*(Y/H),format=gray[grad];[0:v]boxblur=4[blur];[blur][grad]alphamerge[alpha];[0:v][alpha]overlay" output.mp4
5298 Fix the banding artifacts that are sometimes introduced into nearly flat
5299 regions by truncation to 8bit color depth.
5300 Interpolate the gradients that should go where the bands are, and
5303 It is designed for playback only. Do not use it prior to
5304 lossy compression, because compression tends to lose the dither and
5305 bring back the bands.
5307 It accepts the following parameters:
5312 The maximum amount by which the filter will change any one pixel. This is also
5313 the threshold for detecting nearly flat regions. Acceptable values range from
5314 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
5318 The neighborhood to fit the gradient to. A larger radius makes for smoother
5319 gradients, but also prevents the filter from modifying the pixels near detailed
5320 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
5321 values will be clipped to the valid range.
5325 Alternatively, the options can be specified as a flat string:
5326 @var{strength}[:@var{radius}]
5328 @subsection Examples
5332 Apply the filter with a @code{3.5} strength and radius of @code{8}:
5338 Specify radius, omitting the strength (which will fall-back to the default
5349 Apply a Hald CLUT to a video stream.
5351 First input is the video stream to process, and second one is the Hald CLUT.
5352 The Hald CLUT input can be a simple picture or a complete video stream.
5354 The filter accepts the following options:
5358 Force termination when the shortest input terminates. Default is @code{0}.
5360 Continue applying the last CLUT after the end of the stream. A value of
5361 @code{0} disable the filter after the last frame of the CLUT is reached.
5362 Default is @code{1}.
5365 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
5366 filters share the same internals).
5368 More information about the Hald CLUT can be found on Eskil Steenberg's website
5369 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
5371 @subsection Workflow examples
5373 @subsubsection Hald CLUT video stream
5375 Generate an identity Hald CLUT stream altered with various effects:
5377 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
5380 Note: make sure you use a lossless codec.
5382 Then use it with @code{haldclut} to apply it on some random stream:
5384 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
5387 The Hald CLUT will be applied to the 10 first seconds (duration of
5388 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
5389 to the remaining frames of the @code{mandelbrot} stream.
5391 @subsubsection Hald CLUT with preview
5393 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
5394 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
5395 biggest possible square starting at the top left of the picture. The remaining
5396 padding pixels (bottom or right) will be ignored. This area can be used to add
5397 a preview of the Hald CLUT.
5399 Typically, the following generated Hald CLUT will be supported by the
5400 @code{haldclut} filter:
5403 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
5404 pad=iw+320 [padded_clut];
5405 smptebars=s=320x256, split [a][b];
5406 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
5407 [main][b] overlay=W-320" -frames:v 1 clut.png
5410 It contains the original and a preview of the effect of the CLUT: SMPTE color
5411 bars are displayed on the right-top, and below the same color bars processed by
5414 Then, the effect of this Hald CLUT can be visualized with:
5416 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
5421 Flip the input video horizontally.
5423 For example, to horizontally flip the input video with @command{ffmpeg}:
5425 ffmpeg -i in.avi -vf "hflip" out.avi
5429 This filter applies a global color histogram equalization on a
5432 It can be used to correct video that has a compressed range of pixel
5433 intensities. The filter redistributes the pixel intensities to
5434 equalize their distribution across the intensity range. It may be
5435 viewed as an "automatically adjusting contrast filter". This filter is
5436 useful only for correcting degraded or poorly captured source
5439 The filter accepts the following options:
5443 Determine the amount of equalization to be applied. As the strength
5444 is reduced, the distribution of pixel intensities more-and-more
5445 approaches that of the input frame. The value must be a float number
5446 in the range [0,1] and defaults to 0.200.
5449 Set the maximum intensity that can generated and scale the output
5450 values appropriately. The strength should be set as desired and then
5451 the intensity can be limited if needed to avoid washing-out. The value
5452 must be a float number in the range [0,1] and defaults to 0.210.
5455 Set the antibanding level. If enabled the filter will randomly vary
5456 the luminance of output pixels by a small amount to avoid banding of
5457 the histogram. Possible values are @code{none}, @code{weak} or
5458 @code{strong}. It defaults to @code{none}.
5463 Compute and draw a color distribution histogram for the input video.
5465 The computed histogram is a representation of the color component
5466 distribution in an image.
5468 The filter accepts the following options:
5474 It accepts the following values:
5477 Standard histogram that displays the color components distribution in an
5478 image. Displays color graph for each color component. Shows distribution of
5479 the Y, U, V, A or R, G, B components, depending on input format, in the
5480 current frame. Below each graph a color component scale meter is shown.
5483 Displays chroma values (U/V color placement) in a two dimensional
5484 graph (which is called a vectorscope). The brighter a pixel in the
5485 vectorscope, the more pixels of the input frame correspond to that pixel
5486 (i.e., more pixels have this chroma value). The V component is displayed on
5487 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5488 side being V = 255. The U component is displayed on the vertical (Y) axis,
5489 with the top representing U = 0 and the bottom representing U = 255.
5491 The position of a white pixel in the graph corresponds to the chroma value of
5492 a pixel of the input clip. The graph can therefore be used to read the hue
5493 (color flavor) and the saturation (the dominance of the hue in the color). As
5494 the hue of a color changes, it moves around the square. At the center of the
5495 square the saturation is zero, which means that the corresponding pixel has no
5496 color. If the amount of a specific color is increased (while leaving the other
5497 colors unchanged) the saturation increases, and the indicator moves towards
5498 the edge of the square.
5501 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5505 Per row/column color component graph. In row mode, the graph on the left side
5506 represents color component value 0 and the right side represents value = 255.
5507 In column mode, the top side represents color component value = 0 and bottom
5508 side represents value = 255.
5510 Default value is @code{levels}.
5513 Set height of level in @code{levels}. Default value is @code{200}.
5514 Allowed range is [50, 2048].
5517 Set height of color scale in @code{levels}. Default value is @code{12}.
5518 Allowed range is [0, 40].
5521 Set step for @code{waveform} mode. Smaller values are useful to find out how
5522 many values of the same luminance are distributed across input rows/columns.
5523 Default value is @code{10}. Allowed range is [1, 255].
5526 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5527 Default is @code{row}.
5529 @item waveform_mirror
5530 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5531 means mirrored. In mirrored mode, higher values will be represented on the left
5532 side for @code{row} mode and at the top for @code{column} mode. Default is
5533 @code{0} (unmirrored).
5536 Set display mode for @code{waveform} and @code{levels}.
5537 It accepts the following values:
5540 Display separate graph for the color components side by side in
5541 @code{row} waveform mode or one below the other in @code{column} waveform mode
5542 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5543 per color component graphs are placed below each other.
5545 Using this display mode in @code{waveform} histogram mode makes it easy to
5546 spot color casts in the highlights and shadows of an image, by comparing the
5547 contours of the top and the bottom graphs of each waveform. Since whites,
5548 grays, and blacks are characterized by exactly equal amounts of red, green,
5549 and blue, neutral areas of the picture should display three waveforms of
5550 roughly equal width/height. If not, the correction is easy to perform by
5551 making level adjustments the three waveforms.
5554 Presents information identical to that in the @code{parade}, except
5555 that the graphs representing color components are superimposed directly
5558 This display mode in @code{waveform} histogram mode makes it easier to spot
5559 relative differences or similarities in overlapping areas of the color
5560 components that are supposed to be identical, such as neutral whites, grays,
5563 Default is @code{parade}.
5566 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5567 Default is @code{linear}.
5570 @subsection Examples
5575 Calculate and draw histogram:
5577 ffplay -i input -vf histogram
5585 This is a high precision/quality 3d denoise filter. It aims to reduce
5586 image noise, producing smooth images and making still images really
5587 still. It should enhance compressibility.
5589 It accepts the following optional parameters:
5593 A non-negative floating point number which specifies spatial luma strength.
5596 @item chroma_spatial
5597 A non-negative floating point number which specifies spatial chroma strength.
5598 It defaults to 3.0*@var{luma_spatial}/4.0.
5601 A floating point number which specifies luma temporal strength. It defaults to
5602 6.0*@var{luma_spatial}/4.0.
5605 A floating point number which specifies chroma temporal strength. It defaults to
5606 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5611 Apply a high-quality magnification filter designed for pixel art. This filter
5612 was originally created by Maxim Stepin.
5614 It accepts the following option:
5618 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
5619 @code{hq3x} and @code{4} for @code{hq4x}.
5620 Default is @code{3}.
5625 Modify the hue and/or the saturation of the input.
5627 It accepts the following parameters:
5631 Specify the hue angle as a number of degrees. It accepts an expression,
5632 and defaults to "0".
5635 Specify the saturation in the [-10,10] range. It accepts an expression and
5639 Specify the hue angle as a number of radians. It accepts an
5640 expression, and defaults to "0".
5643 Specify the brightness in the [-10,10] range. It accepts an expression and
5647 @option{h} and @option{H} are mutually exclusive, and can't be
5648 specified at the same time.
5650 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5651 expressions containing the following constants:
5655 frame count of the input frame starting from 0
5658 presentation timestamp of the input frame expressed in time base units
5661 frame rate of the input video, NAN if the input frame rate is unknown
5664 timestamp expressed in seconds, NAN if the input timestamp is unknown
5667 time base of the input video
5670 @subsection Examples
5674 Set the hue to 90 degrees and the saturation to 1.0:
5680 Same command but expressing the hue in radians:
5686 Rotate hue and make the saturation swing between 0
5687 and 2 over a period of 1 second:
5689 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5693 Apply a 3 seconds saturation fade-in effect starting at 0:
5698 The general fade-in expression can be written as:
5700 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5704 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5706 hue="s=max(0\, min(1\, (8-t)/3))"
5709 The general fade-out expression can be written as:
5711 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5716 @subsection Commands
5718 This filter supports the following commands:
5724 Modify the hue and/or the saturation and/or brightness of the input video.
5725 The command accepts the same syntax of the corresponding option.
5727 If the specified expression is not valid, it is kept at its current
5733 Detect video interlacing type.
5735 This filter tries to detect if the input frames as interlaced, progressive,
5736 top or bottom field first. It will also try and detect fields that are
5737 repeated between adjacent frames (a sign of telecine).
5739 Single frame detection considers only immediately adjacent frames when classifying each frame.
5740 Multiple frame detection incorporates the classification history of previous frames.
5742 The filter will log these metadata values:
5745 @item single.current_frame
5746 Detected type of current frame using single-frame detection. One of:
5747 ``tff'' (top field first), ``bff'' (bottom field first),
5748 ``progressive'', or ``undetermined''
5751 Cumulative number of frames detected as top field first using single-frame detection.
5754 Cumulative number of frames detected as top field first using multiple-frame detection.
5757 Cumulative number of frames detected as bottom field first using single-frame detection.
5759 @item multiple.current_frame
5760 Detected type of current frame using multiple-frame detection. One of:
5761 ``tff'' (top field first), ``bff'' (bottom field first),
5762 ``progressive'', or ``undetermined''
5765 Cumulative number of frames detected as bottom field first using multiple-frame detection.
5767 @item single.progressive
5768 Cumulative number of frames detected as progressive using single-frame detection.
5770 @item multiple.progressive
5771 Cumulative number of frames detected as progressive using multiple-frame detection.
5773 @item single.undetermined
5774 Cumulative number of frames that could not be classified using single-frame detection.
5776 @item multiple.undetermined
5777 Cumulative number of frames that could not be classified using multiple-frame detection.
5779 @item repeated.current_frame
5780 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
5782 @item repeated.neither
5783 Cumulative number of frames with no repeated field.
5786 Cumulative number of frames with the top field repeated from the previous frame's top field.
5788 @item repeated.bottom
5789 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
5792 The filter accepts the following options:
5796 Set interlacing threshold.
5798 Set progressive threshold.
5800 Threshold for repeated field detection.
5802 Number of frames after which a given frame's contribution to the
5803 statistics is halved (i.e., it contributes only 0.5 to it's
5804 classification). The default of 0 means that all frames seen are given
5805 full weight of 1.0 forever.
5806 @item analyze_interlaced_flag
5807 When this is not 0 then idet will use the specified number of frames to determine
5808 if the interlaced flag is accurate, it will not count undetermined frames.
5809 If the flag is found to be accurate it will be used without any further
5810 computations, if it is found to be inaccuarte it will be cleared without any
5811 further computations. This allows inserting the idet filter as a low computational
5812 method to clean up the interlaced flag
5817 Deinterleave or interleave fields.
5819 This filter allows one to process interlaced images fields without
5820 deinterlacing them. Deinterleaving splits the input frame into 2
5821 fields (so called half pictures). Odd lines are moved to the top
5822 half of the output image, even lines to the bottom half.
5823 You can process (filter) them independently and then re-interleave them.
5825 The filter accepts the following options:
5829 @item chroma_mode, c
5831 Available values for @var{luma_mode}, @var{chroma_mode} and
5832 @var{alpha_mode} are:
5838 @item deinterleave, d
5839 Deinterleave fields, placing one above the other.
5842 Interleave fields. Reverse the effect of deinterleaving.
5844 Default value is @code{none}.
5847 @item chroma_swap, cs
5848 @item alpha_swap, as
5849 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5854 Simple interlacing filter from progressive contents. This interleaves upper (or
5855 lower) lines from odd frames with lower (or upper) lines from even frames,
5856 halving the frame rate and preserving image height.
5859 Original Original New Frame
5860 Frame 'j' Frame 'j+1' (tff)
5861 ========== =========== ==================
5862 Line 0 --------------------> Frame 'j' Line 0
5863 Line 1 Line 1 ----> Frame 'j+1' Line 1
5864 Line 2 ---------------------> Frame 'j' Line 2
5865 Line 3 Line 3 ----> Frame 'j+1' Line 3
5867 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5870 It accepts the following optional parameters:
5874 This determines whether the interlaced frame is taken from the even
5875 (tff - default) or odd (bff) lines of the progressive frame.
5878 Enable (default) or disable the vertical lowpass filter to avoid twitter
5879 interlacing and reduce moire patterns.
5884 Deinterlace input video by applying Donald Graft's adaptive kernel
5885 deinterling. Work on interlaced parts of a video to produce
5888 The description of the accepted parameters follows.
5892 Set the threshold which affects the filter's tolerance when
5893 determining if a pixel line must be processed. It must be an integer
5894 in the range [0,255] and defaults to 10. A value of 0 will result in
5895 applying the process on every pixels.
5898 Paint pixels exceeding the threshold value to white if set to 1.
5902 Set the fields order. Swap fields if set to 1, leave fields alone if
5906 Enable additional sharpening if set to 1. Default is 0.
5909 Enable twoway sharpening if set to 1. Default is 0.
5912 @subsection Examples
5916 Apply default values:
5918 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5922 Enable additional sharpening:
5928 Paint processed pixels in white:
5934 @section lenscorrection
5936 Correct radial lens distortion
5938 This filter can be used to correct for radial distortion as can result from the use
5939 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
5940 one can use tools available for example as part of opencv or simply trial-and-error.
5941 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
5942 and extract the k1 and k2 coefficients from the resulting matrix.
5944 Note that effectively the same filter is available in the open-source tools Krita and
5945 Digikam from the KDE project.
5947 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
5948 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
5949 brightness distribution, so you may want to use both filters together in certain
5950 cases, though you will have to take care of ordering, i.e. whether vignetting should
5951 be applied before or after lens correction.
5955 The filter accepts the following options:
5959 Relative x-coordinate of the focal point of the image, and thereby the center of the
5960 distortion. This value has a range [0,1] and is expressed as fractions of the image
5963 Relative y-coordinate of the focal point of the image, and thereby the center of the
5964 distortion. This value has a range [0,1] and is expressed as fractions of the image
5967 Coefficient of the quadratic correction term. 0.5 means no correction.
5969 Coefficient of the double quadratic correction term. 0.5 means no correction.
5972 The formula that generates the correction is:
5974 @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)
5976 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
5977 distances from the focal point in the source and target images, respectively.
5982 Apply a 3D LUT to an input video.
5984 The filter accepts the following options:
5988 Set the 3D LUT file name.
5990 Currently supported formats:
6002 Select interpolation mode.
6004 Available values are:
6008 Use values from the nearest defined point.
6010 Interpolate values using the 8 points defining a cube.
6012 Interpolate values using a tetrahedron.
6016 @section lut, lutrgb, lutyuv
6018 Compute a look-up table for binding each pixel component input value
6019 to an output value, and apply it to the input video.
6021 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
6022 to an RGB input video.
6024 These filters accept the following parameters:
6027 set first pixel component expression
6029 set second pixel component expression
6031 set third pixel component expression
6033 set fourth pixel component expression, corresponds to the alpha component
6036 set red component expression
6038 set green component expression
6040 set blue component expression
6042 alpha component expression
6045 set Y/luminance component expression
6047 set U/Cb component expression
6049 set V/Cr component expression
6052 Each of them specifies the expression to use for computing the lookup table for
6053 the corresponding pixel component values.
6055 The exact component associated to each of the @var{c*} options depends on the
6058 The @var{lut} filter requires either YUV or RGB pixel formats in input,
6059 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
6061 The expressions can contain the following constants and functions:
6066 The input width and height.
6069 The input value for the pixel component.
6072 The input value, clipped to the @var{minval}-@var{maxval} range.
6075 The maximum value for the pixel component.
6078 The minimum value for the pixel component.
6081 The negated value for the pixel component value, clipped to the
6082 @var{minval}-@var{maxval} range; it corresponds to the expression
6083 "maxval-clipval+minval".
6086 The computed value in @var{val}, clipped to the
6087 @var{minval}-@var{maxval} range.
6089 @item gammaval(gamma)
6090 The computed gamma correction value of the pixel component value,
6091 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
6093 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
6097 All expressions default to "val".
6099 @subsection Examples
6105 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
6106 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
6109 The above is the same as:
6111 lutrgb="r=negval:g=negval:b=negval"
6112 lutyuv="y=negval:u=negval:v=negval"
6122 Remove chroma components, turning the video into a graytone image:
6124 lutyuv="u=128:v=128"
6128 Apply a luma burning effect:
6134 Remove green and blue components:
6140 Set a constant alpha channel value on input:
6142 format=rgba,lutrgb=a="maxval-minval/2"
6146 Correct luminance gamma by a factor of 0.5:
6148 lutyuv=y=gammaval(0.5)
6152 Discard least significant bits of luma:
6154 lutyuv=y='bitand(val, 128+64+32)'
6158 @section mergeplanes
6160 Merge color channel components from several video streams.
6162 The filter accepts up to 4 input streams, and merge selected input
6163 planes to the output video.
6165 This filter accepts the following options:
6168 Set input to output plane mapping. Default is @code{0}.
6170 The mappings is specified as a bitmap. It should be specified as a
6171 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
6172 mapping for the first plane of the output stream. 'A' sets the number of
6173 the input stream to use (from 0 to 3), and 'a' the plane number of the
6174 corresponding input to use (from 0 to 3). The rest of the mappings is
6175 similar, 'Bb' describes the mapping for the output stream second
6176 plane, 'Cc' describes the mapping for the output stream third plane and
6177 'Dd' describes the mapping for the output stream fourth plane.
6180 Set output pixel format. Default is @code{yuva444p}.
6183 @subsection Examples
6187 Merge three gray video streams of same width and height into single video stream:
6189 [a0][a1][a2]mergeplanes=0x001020:yuv444p
6193 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
6195 [a0][a1]mergeplanes=0x00010210:yuva444p
6199 Swap Y and A plane in yuva444p stream:
6201 format=yuva444p,mergeplanes=0x03010200:yuva444p
6205 Swap U and V plane in yuv420p stream:
6207 format=yuv420p,mergeplanes=0x000201:yuv420p
6211 Cast a rgb24 clip to yuv444p:
6213 format=rgb24,mergeplanes=0x000102:yuv444p
6219 Apply motion-compensation deinterlacing.
6221 It needs one field per frame as input and must thus be used together
6222 with yadif=1/3 or equivalent.
6224 This filter accepts the following options:
6227 Set the deinterlacing mode.
6229 It accepts one of the following values:
6234 use iterative motion estimation
6236 like @samp{slow}, but use multiple reference frames.
6238 Default value is @samp{fast}.
6241 Set the picture field parity assumed for the input video. It must be
6242 one of the following values:
6246 assume top field first
6248 assume bottom field first
6251 Default value is @samp{bff}.
6254 Set per-block quantization parameter (QP) used by the internal
6257 Higher values should result in a smoother motion vector field but less
6258 optimal individual vectors. Default value is 1.
6263 Apply an MPlayer filter to the input video.
6265 This filter provides a wrapper around some of the filters of
6268 This wrapper is considered experimental. Some of the wrapped filters
6269 may not work properly and we may drop support for them, as they will
6270 be implemented natively into FFmpeg. Thus you should avoid
6271 depending on them when writing portable scripts.
6273 The filter accepts the parameters:
6274 @var{filter_name}[:=]@var{filter_params}
6276 @var{filter_name} is the name of a supported MPlayer filter,
6277 @var{filter_params} is a string containing the parameters accepted by
6280 The list of the currently supported filters follows:
6285 The parameter syntax and behavior for the listed filters are the same
6286 of the corresponding MPlayer filters. For detailed instructions check
6287 the "VIDEO FILTERS" section in the MPlayer manual.
6289 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
6293 Drop frames that do not differ greatly from the previous frame in
6294 order to reduce frame rate.
6296 The main use of this filter is for very-low-bitrate encoding
6297 (e.g. streaming over dialup modem), but it could in theory be used for
6298 fixing movies that were inverse-telecined incorrectly.
6300 A description of the accepted options follows.
6304 Set the maximum number of consecutive frames which can be dropped (if
6305 positive), or the minimum interval between dropped frames (if
6306 negative). If the value is 0, the frame is dropped unregarding the
6307 number of previous sequentially dropped frames.
6314 Set the dropping threshold values.
6316 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
6317 represent actual pixel value differences, so a threshold of 64
6318 corresponds to 1 unit of difference for each pixel, or the same spread
6319 out differently over the block.
6321 A frame is a candidate for dropping if no 8x8 blocks differ by more
6322 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
6323 meaning the whole image) differ by more than a threshold of @option{lo}.
6325 Default value for @option{hi} is 64*12, default value for @option{lo} is
6326 64*5, and default value for @option{frac} is 0.33.
6334 It accepts an integer in input; if non-zero it negates the
6335 alpha component (if available). The default value in input is 0.
6339 Force libavfilter not to use any of the specified pixel formats for the
6340 input to the next filter.
6342 It accepts the following parameters:
6346 A '|'-separated list of pixel format names, such as
6347 apix_fmts=yuv420p|monow|rgb24".
6351 @subsection Examples
6355 Force libavfilter to use a format different from @var{yuv420p} for the
6356 input to the vflip filter:
6358 noformat=pix_fmts=yuv420p,vflip
6362 Convert the input video to any of the formats not contained in the list:
6364 noformat=yuv420p|yuv444p|yuv410p
6370 Add noise on video input frame.
6372 The filter accepts the following options:
6380 Set noise seed for specific pixel component or all pixel components in case
6381 of @var{all_seed}. Default value is @code{123457}.
6383 @item all_strength, alls
6384 @item c0_strength, c0s
6385 @item c1_strength, c1s
6386 @item c2_strength, c2s
6387 @item c3_strength, c3s
6388 Set noise strength for specific pixel component or all pixel components in case
6389 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
6391 @item all_flags, allf
6396 Set pixel component flags or set flags for all components if @var{all_flags}.
6397 Available values for component flags are:
6400 averaged temporal noise (smoother)
6402 mix random noise with a (semi)regular pattern
6404 temporal noise (noise pattern changes between frames)
6406 uniform noise (gaussian otherwise)
6410 @subsection Examples
6412 Add temporal and uniform noise to input video:
6414 noise=alls=20:allf=t+u
6419 Pass the video source unchanged to the output.
6423 Apply a video transform using libopencv.
6425 To enable this filter, install the libopencv library and headers and
6426 configure FFmpeg with @code{--enable-libopencv}.
6428 It accepts the following parameters:
6433 The name of the libopencv filter to apply.
6436 The parameters to pass to the libopencv filter. If not specified, the default
6441 Refer to the official libopencv documentation for more precise
6443 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
6445 Several libopencv filters are supported; see the following subsections.
6450 Dilate an image by using a specific structuring element.
6451 It corresponds to the libopencv function @code{cvDilate}.
6453 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
6455 @var{struct_el} represents a structuring element, and has the syntax:
6456 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
6458 @var{cols} and @var{rows} represent the number of columns and rows of
6459 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
6460 point, and @var{shape} the shape for the structuring element. @var{shape}
6461 must be "rect", "cross", "ellipse", or "custom".
6463 If the value for @var{shape} is "custom", it must be followed by a
6464 string of the form "=@var{filename}". The file with name
6465 @var{filename} is assumed to represent a binary image, with each
6466 printable character corresponding to a bright pixel. When a custom
6467 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
6468 or columns and rows of the read file are assumed instead.
6470 The default value for @var{struct_el} is "3x3+0x0/rect".
6472 @var{nb_iterations} specifies the number of times the transform is
6473 applied to the image, and defaults to 1.
6477 # Use the default values
6480 # Dilate using a structuring element with a 5x5 cross, iterating two times
6481 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
6483 # Read the shape from the file diamond.shape, iterating two times.
6484 # The file diamond.shape may contain a pattern of characters like this
6490 # The specified columns and rows are ignored
6491 # but the anchor point coordinates are not
6492 ocv=dilate:0x0+2x2/custom=diamond.shape|2
6497 Erode an image by using a specific structuring element.
6498 It corresponds to the libopencv function @code{cvErode}.
6500 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
6501 with the same syntax and semantics as the @ref{dilate} filter.
6505 Smooth the input video.
6507 The filter takes the following parameters:
6508 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
6510 @var{type} is the type of smooth filter to apply, and must be one of
6511 the following values: "blur", "blur_no_scale", "median", "gaussian",
6512 or "bilateral". The default value is "gaussian".
6514 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
6515 depend on the smooth type. @var{param1} and
6516 @var{param2} accept integer positive values or 0. @var{param3} and
6517 @var{param4} accept floating point values.
6519 The default value for @var{param1} is 3. The default value for the
6520 other parameters is 0.
6522 These parameters correspond to the parameters assigned to the
6523 libopencv function @code{cvSmooth}.
6528 Overlay one video on top of another.
6530 It takes two inputs and has one output. The first input is the "main"
6531 video on which the second input is overlaid.
6533 It accepts the following parameters:
6535 A description of the accepted options follows.
6540 Set the expression for the x and y coordinates of the overlaid video
6541 on the main video. Default value is "0" for both expressions. In case
6542 the expression is invalid, it is set to a huge value (meaning that the
6543 overlay will not be displayed within the output visible area).
6546 The action to take when EOF is encountered on the secondary input; it accepts
6547 one of the following values:
6551 Repeat the last frame (the default).
6555 Pass the main input through.
6559 Set when the expressions for @option{x}, and @option{y} are evaluated.
6561 It accepts the following values:
6564 only evaluate expressions once during the filter initialization or
6565 when a command is processed
6568 evaluate expressions for each incoming frame
6571 Default value is @samp{frame}.
6574 If set to 1, force the output to terminate when the shortest input
6575 terminates. Default value is 0.
6578 Set the format for the output video.
6580 It accepts the following values:
6595 Default value is @samp{yuv420}.
6597 @item rgb @emph{(deprecated)}
6598 If set to 1, force the filter to accept inputs in the RGB
6599 color space. Default value is 0. This option is deprecated, use
6600 @option{format} instead.
6603 If set to 1, force the filter to draw the last overlay frame over the
6604 main input until the end of the stream. A value of 0 disables this
6605 behavior. Default value is 1.
6608 The @option{x}, and @option{y} expressions can contain the following
6614 The main input width and height.
6618 The overlay input width and height.
6622 The computed values for @var{x} and @var{y}. They are evaluated for
6627 horizontal and vertical chroma subsample values of the output
6628 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6632 the number of input frame, starting from 0
6635 the position in the file of the input frame, NAN if unknown
6638 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6642 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6643 when evaluation is done @emph{per frame}, and will evaluate to NAN
6644 when @option{eval} is set to @samp{init}.
6646 Be aware that frames are taken from each input video in timestamp
6647 order, hence, if their initial timestamps differ, it is a good idea
6648 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6649 have them begin in the same zero timestamp, as the example for
6650 the @var{movie} filter does.
6652 You can chain together more overlays but you should test the
6653 efficiency of such approach.
6655 @subsection Commands
6657 This filter supports the following commands:
6661 Modify the x and y of the overlay input.
6662 The command accepts the same syntax of the corresponding option.
6664 If the specified expression is not valid, it is kept at its current
6668 @subsection Examples
6672 Draw the overlay at 10 pixels from the bottom right corner of the main
6675 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6678 Using named options the example above becomes:
6680 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6684 Insert a transparent PNG logo in the bottom left corner of the input,
6685 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6687 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6691 Insert 2 different transparent PNG logos (second logo on bottom
6692 right corner) using the @command{ffmpeg} tool:
6694 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
6698 Add a transparent color layer on top of the main video; @code{WxH}
6699 must specify the size of the main input to the overlay filter:
6701 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6705 Play an original video and a filtered version (here with the deshake
6706 filter) side by side using the @command{ffplay} tool:
6708 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6711 The above command is the same as:
6713 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6717 Make a sliding overlay appearing from the left to the right top part of the
6718 screen starting since time 2:
6720 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6724 Compose output by putting two input videos side to side:
6726 ffmpeg -i left.avi -i right.avi -filter_complex "
6727 nullsrc=size=200x100 [background];
6728 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6729 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6730 [background][left] overlay=shortest=1 [background+left];
6731 [background+left][right] overlay=shortest=1:x=100 [left+right]
6736 Mask 10-20 seconds of a video by applying the delogo filter to a section
6738 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6739 -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]'
6744 Chain several overlays in cascade:
6746 nullsrc=s=200x200 [bg];
6747 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6748 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6749 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6750 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6751 [in3] null, [mid2] overlay=100:100 [out0]
6758 Apply Overcomplete Wavelet denoiser.
6760 The filter accepts the following options:
6766 Larger depth values will denoise lower frequency components more, but
6767 slow down filtering.
6769 Must be an int in the range 8-16, default is @code{8}.
6771 @item luma_strength, ls
6774 Must be a double value in the range 0-1000, default is @code{1.0}.
6776 @item chroma_strength, cs
6777 Set chroma strength.
6779 Must be a double value in the range 0-1000, default is @code{1.0}.
6784 Add paddings to the input image, and place the original input at the
6785 provided @var{x}, @var{y} coordinates.
6787 It accepts the following parameters:
6792 Specify an expression for the size of the output image with the
6793 paddings added. If the value for @var{width} or @var{height} is 0, the
6794 corresponding input size is used for the output.
6796 The @var{width} expression can reference the value set by the
6797 @var{height} expression, and vice versa.
6799 The default value of @var{width} and @var{height} is 0.
6803 Specify the offsets to place the input image at within the padded area,
6804 with respect to the top/left border of the output image.
6806 The @var{x} expression can reference the value set by the @var{y}
6807 expression, and vice versa.
6809 The default value of @var{x} and @var{y} is 0.
6812 Specify the color of the padded area. For the syntax of this option,
6813 check the "Color" section in the ffmpeg-utils manual.
6815 The default value of @var{color} is "black".
6818 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6819 options are expressions containing the following constants:
6824 The input video width and height.
6828 These are the same as @var{in_w} and @var{in_h}.
6832 The output width and height (the size of the padded area), as
6833 specified by the @var{width} and @var{height} expressions.
6837 These are the same as @var{out_w} and @var{out_h}.
6841 The x and y offsets as specified by the @var{x} and @var{y}
6842 expressions, or NAN if not yet specified.
6845 same as @var{iw} / @var{ih}
6848 input sample aspect ratio
6851 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6855 The horizontal and vertical chroma subsample values. For example for the
6856 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6859 @subsection Examples
6863 Add paddings with the color "violet" to the input video. The output video
6864 size is 640x480, and the top-left corner of the input video is placed at
6867 pad=640:480:0:40:violet
6870 The example above is equivalent to the following command:
6872 pad=width=640:height=480:x=0:y=40:color=violet
6876 Pad the input to get an output with dimensions increased by 3/2,
6877 and put the input video at the center of the padded area:
6879 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6883 Pad the input to get a squared output with size equal to the maximum
6884 value between the input width and height, and put the input video at
6885 the center of the padded area:
6887 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6891 Pad the input to get a final w/h ratio of 16:9:
6893 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6897 In case of anamorphic video, in order to set the output display aspect
6898 correctly, it is necessary to use @var{sar} in the expression,
6899 according to the relation:
6901 (ih * X / ih) * sar = output_dar
6902 X = output_dar / sar
6905 Thus the previous example needs to be modified to:
6907 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6911 Double the output size and put the input video in the bottom-right
6912 corner of the output padded area:
6914 pad="2*iw:2*ih:ow-iw:oh-ih"
6918 @section perspective
6920 Correct perspective of video not recorded perpendicular to the screen.
6922 A description of the accepted parameters follows.
6933 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6934 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6935 If the @code{sense} option is set to @code{source}, then the specified points will be sent
6936 to the corners of the destination. If the @code{sense} option is set to @code{destination},
6937 then the corners of the source will be sent to the specified coordinates.
6939 The expressions can use the following variables:
6944 the width and height of video frame.
6948 Set interpolation for perspective correction.
6950 It accepts the following values:
6956 Default value is @samp{linear}.
6959 Set interpretation of coordinate options.
6961 It accepts the following values:
6965 Send point in the source specified by the given coordinates to
6966 the corners of the destination.
6968 @item 1, destination
6970 Send the corners of the source to the point in the destination specified
6971 by the given coordinates.
6973 Default value is @samp{source}.
6979 Delay interlaced video by one field time so that the field order changes.
6981 The intended use is to fix PAL movies that have been captured with the
6982 opposite field order to the film-to-video transfer.
6984 A description of the accepted parameters follows.
6990 It accepts the following values:
6993 Capture field order top-first, transfer bottom-first.
6994 Filter will delay the bottom field.
6997 Capture field order bottom-first, transfer top-first.
6998 Filter will delay the top field.
7001 Capture and transfer with the same field order. This mode only exists
7002 for the documentation of the other options to refer to, but if you
7003 actually select it, the filter will faithfully do nothing.
7006 Capture field order determined automatically by field flags, transfer
7008 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
7009 basis using field flags. If no field information is available,
7010 then this works just like @samp{u}.
7013 Capture unknown or varying, transfer opposite.
7014 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
7015 analyzing the images and selecting the alternative that produces best
7016 match between the fields.
7019 Capture top-first, transfer unknown or varying.
7020 Filter selects among @samp{t} and @samp{p} using image analysis.
7023 Capture bottom-first, transfer unknown or varying.
7024 Filter selects among @samp{b} and @samp{p} using image analysis.
7027 Capture determined by field flags, transfer unknown or varying.
7028 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
7029 image analysis. If no field information is available, then this works just
7030 like @samp{U}. This is the default mode.
7033 Both capture and transfer unknown or varying.
7034 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
7038 @section pixdesctest
7040 Pixel format descriptor test filter, mainly useful for internal
7041 testing. The output video should be equal to the input video.
7045 format=monow, pixdesctest
7048 can be used to test the monowhite pixel format descriptor definition.
7052 Enable the specified chain of postprocessing subfilters using libpostproc. This
7053 library should be automatically selected with a GPL build (@code{--enable-gpl}).
7054 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
7055 Each subfilter and some options have a short and a long name that can be used
7056 interchangeably, i.e. dr/dering are the same.
7058 The filters accept the following options:
7062 Set postprocessing subfilters string.
7065 All subfilters share common options to determine their scope:
7069 Honor the quality commands for this subfilter.
7072 Do chrominance filtering, too (default).
7075 Do luminance filtering only (no chrominance).
7078 Do chrominance filtering only (no luminance).
7081 These options can be appended after the subfilter name, separated by a '|'.
7083 Available subfilters are:
7086 @item hb/hdeblock[|difference[|flatness]]
7087 Horizontal deblocking filter
7090 Difference factor where higher values mean more deblocking (default: @code{32}).
7092 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7095 @item vb/vdeblock[|difference[|flatness]]
7096 Vertical deblocking filter
7099 Difference factor where higher values mean more deblocking (default: @code{32}).
7101 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7104 @item ha/hadeblock[|difference[|flatness]]
7105 Accurate horizontal deblocking filter
7108 Difference factor where higher values mean more deblocking (default: @code{32}).
7110 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7113 @item va/vadeblock[|difference[|flatness]]
7114 Accurate vertical deblocking filter
7117 Difference factor where higher values mean more deblocking (default: @code{32}).
7119 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7123 The horizontal and vertical deblocking filters share the difference and
7124 flatness values so you cannot set different horizontal and vertical
7129 Experimental horizontal deblocking filter
7132 Experimental vertical deblocking filter
7137 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
7140 larger -> stronger filtering
7142 larger -> stronger filtering
7144 larger -> stronger filtering
7147 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
7150 Stretch luminance to @code{0-255}.
7153 @item lb/linblenddeint
7154 Linear blend deinterlacing filter that deinterlaces the given block by
7155 filtering all lines with a @code{(1 2 1)} filter.
7157 @item li/linipoldeint
7158 Linear interpolating deinterlacing filter that deinterlaces the given block by
7159 linearly interpolating every second line.
7161 @item ci/cubicipoldeint
7162 Cubic interpolating deinterlacing filter deinterlaces the given block by
7163 cubically interpolating every second line.
7165 @item md/mediandeint
7166 Median deinterlacing filter that deinterlaces the given block by applying a
7167 median filter to every second line.
7169 @item fd/ffmpegdeint
7170 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
7171 second line with a @code{(-1 4 2 4 -1)} filter.
7174 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
7175 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
7177 @item fq/forceQuant[|quantizer]
7178 Overrides the quantizer table from the input with the constant quantizer you
7186 Default pp filter combination (@code{hb|a,vb|a,dr|a})
7189 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
7192 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
7195 @subsection Examples
7199 Apply horizontal and vertical deblocking, deringing and automatic
7200 brightness/contrast:
7206 Apply default filters without brightness/contrast correction:
7212 Apply default filters and temporal denoiser:
7214 pp=default/tmpnoise|1|2|3
7218 Apply deblocking on luminance only, and switch vertical deblocking on or off
7219 automatically depending on available CPU time:
7226 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
7227 similar to spp = 6 with 7 point DCT, where only the center sample is
7230 The filter accepts the following options:
7234 Force a constant quantization parameter. It accepts an integer in range
7235 0 to 63. If not set, the filter will use the QP from the video stream
7239 Set thresholding mode. Available modes are:
7243 Set hard thresholding.
7245 Set soft thresholding (better de-ringing effect, but likely blurrier).
7247 Set medium thresholding (good results, default).
7253 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
7254 Ratio) between two input videos.
7256 This filter takes in input two input videos, the first input is
7257 considered the "main" source and is passed unchanged to the
7258 output. The second input is used as a "reference" video for computing
7261 Both video inputs must have the same resolution and pixel format for
7262 this filter to work correctly. Also it assumes that both inputs
7263 have the same number of frames, which are compared one by one.
7265 The obtained average PSNR is printed through the logging system.
7267 The filter stores the accumulated MSE (mean squared error) of each
7268 frame, and at the end of the processing it is averaged across all frames
7269 equally, and the following formula is applied to obtain the PSNR:
7272 PSNR = 10*log10(MAX^2/MSE)
7275 Where MAX is the average of the maximum values of each component of the
7278 The description of the accepted parameters follows.
7282 If specified the filter will use the named file to save the PSNR of
7283 each individual frame.
7286 The file printed if @var{stats_file} is selected, contains a sequence of
7287 key/value pairs of the form @var{key}:@var{value} for each compared
7290 A description of each shown parameter follows:
7294 sequential number of the input frame, starting from 1
7297 Mean Square Error pixel-by-pixel average difference of the compared
7298 frames, averaged over all the image components.
7300 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
7301 Mean Square Error pixel-by-pixel average difference of the compared
7302 frames for the component specified by the suffix.
7304 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
7305 Peak Signal to Noise ratio of the compared frames for the component
7306 specified by the suffix.
7311 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
7312 [main][ref] psnr="stats_file=stats.log" [out]
7315 On this example the input file being processed is compared with the
7316 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
7317 is stored in @file{stats.log}.
7322 Pulldown reversal (inverse telecine) filter, capable of handling mixed
7323 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
7326 The pullup filter is designed to take advantage of future context in making
7327 its decisions. This filter is stateless in the sense that it does not lock
7328 onto a pattern to follow, but it instead looks forward to the following
7329 fields in order to identify matches and rebuild progressive frames.
7331 To produce content with an even framerate, insert the fps filter after
7332 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
7333 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
7335 The filter accepts the following options:
7342 These options set the amount of "junk" to ignore at the left, right, top, and
7343 bottom of the image, respectively. Left and right are in units of 8 pixels,
7344 while top and bottom are in units of 2 lines.
7345 The default is 8 pixels on each side.
7348 Set the strict breaks. Setting this option to 1 will reduce the chances of
7349 filter generating an occasional mismatched frame, but it may also cause an
7350 excessive number of frames to be dropped during high motion sequences.
7351 Conversely, setting it to -1 will make filter match fields more easily.
7352 This may help processing of video where there is slight blurring between
7353 the fields, but may also cause there to be interlaced frames in the output.
7354 Default value is @code{0}.
7357 Set the metric plane to use. It accepts the following values:
7363 Use chroma blue plane.
7366 Use chroma red plane.
7369 This option may be set to use chroma plane instead of the default luma plane
7370 for doing filter's computations. This may improve accuracy on very clean
7371 source material, but more likely will decrease accuracy, especially if there
7372 is chroma noise (rainbow effect) or any grayscale video.
7373 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
7374 load and make pullup usable in realtime on slow machines.
7377 For best results (without duplicated frames in the output file) it is
7378 necessary to change the output frame rate. For example, to inverse
7379 telecine NTSC input:
7381 ffmpeg -i input -vf pullup -r 24000/1001 ...
7386 Change video quantization parameters (QP).
7388 The filter accepts the following option:
7392 Set expression for quantization parameter.
7395 The expression is evaluated through the eval API and can contain, among others,
7396 the following constants:
7400 1 if index is not 129, 0 otherwise.
7403 Sequentional index starting from -129 to 128.
7406 @subsection Examples
7418 Suppress a TV station logo, using an image file to determine which
7419 pixels comprise the logo. It works by filling in the pixels that
7420 comprise the logo with neighboring pixels.
7422 The filter accepts the following options:
7426 Set the filter bitmap file, which can be any image format supported by
7427 libavformat. The width and height of the image file must match those of the
7428 video stream being processed.
7431 Pixels in the provided bitmap image with a value of zero are not
7432 considered part of the logo, non-zero pixels are considered part of
7433 the logo. If you use white (255) for the logo and black (0) for the
7434 rest, you will be safe. For making the filter bitmap, it is
7435 recommended to take a screen capture of a black frame with the logo
7436 visible, and then using a threshold filter followed by the erode
7437 filter once or twice.
7439 If needed, little splotches can be fixed manually. Remember that if
7440 logo pixels are not covered, the filter quality will be much
7441 reduced. Marking too many pixels as part of the logo does not hurt as
7442 much, but it will increase the amount of blurring needed to cover over
7443 the image and will destroy more information than necessary, and extra
7444 pixels will slow things down on a large logo.
7448 Rotate video by an arbitrary angle expressed in radians.
7450 The filter accepts the following options:
7452 A description of the optional parameters follows.
7455 Set an expression for the angle by which to rotate the input video
7456 clockwise, expressed as a number of radians. A negative value will
7457 result in a counter-clockwise rotation. By default it is set to "0".
7459 This expression is evaluated for each frame.
7462 Set the output width expression, default value is "iw".
7463 This expression is evaluated just once during configuration.
7466 Set the output height expression, default value is "ih".
7467 This expression is evaluated just once during configuration.
7470 Enable bilinear interpolation if set to 1, a value of 0 disables
7471 it. Default value is 1.
7474 Set the color used to fill the output area not covered by the rotated
7475 image. For the general syntax of this option, check the "Color" section in the
7476 ffmpeg-utils manual. If the special value "none" is selected then no
7477 background is printed (useful for example if the background is never shown).
7479 Default value is "black".
7482 The expressions for the angle and the output size can contain the
7483 following constants and functions:
7487 sequential number of the input frame, starting from 0. It is always NAN
7488 before the first frame is filtered.
7491 time in seconds of the input frame, it is set to 0 when the filter is
7492 configured. It is always NAN before the first frame is filtered.
7496 horizontal and vertical chroma subsample values. For example for the
7497 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7501 the input video width and height
7505 the output width and height, that is the size of the padded area as
7506 specified by the @var{width} and @var{height} expressions
7510 the minimal width/height required for completely containing the input
7511 video rotated by @var{a} radians.
7513 These are only available when computing the @option{out_w} and
7514 @option{out_h} expressions.
7517 @subsection Examples
7521 Rotate the input by PI/6 radians clockwise:
7527 Rotate the input by PI/6 radians counter-clockwise:
7533 Rotate the input by 45 degrees clockwise:
7539 Apply a constant rotation with period T, starting from an angle of PI/3:
7541 rotate=PI/3+2*PI*t/T
7545 Make the input video rotation oscillating with a period of T
7546 seconds and an amplitude of A radians:
7548 rotate=A*sin(2*PI/T*t)
7552 Rotate the video, output size is chosen so that the whole rotating
7553 input video is always completely contained in the output:
7555 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
7559 Rotate the video, reduce the output size so that no background is ever
7562 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
7566 @subsection Commands
7568 The filter supports the following commands:
7572 Set the angle expression.
7573 The command accepts the same syntax of the corresponding option.
7575 If the specified expression is not valid, it is kept at its current
7581 Apply Shape Adaptive Blur.
7583 The filter accepts the following options:
7586 @item luma_radius, lr
7587 Set luma blur filter strength, must be a value in range 0.1-4.0, default
7588 value is 1.0. A greater value will result in a more blurred image, and
7589 in slower processing.
7591 @item luma_pre_filter_radius, lpfr
7592 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
7595 @item luma_strength, ls
7596 Set luma maximum difference between pixels to still be considered, must
7597 be a value in the 0.1-100.0 range, default value is 1.0.
7599 @item chroma_radius, cr
7600 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
7601 greater value will result in a more blurred image, and in slower
7604 @item chroma_pre_filter_radius, cpfr
7605 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
7607 @item chroma_strength, cs
7608 Set chroma maximum difference between pixels to still be considered,
7609 must be a value in the 0.1-100.0 range.
7612 Each chroma option value, if not explicitly specified, is set to the
7613 corresponding luma option value.
7618 Scale (resize) the input video, using the libswscale library.
7620 The scale filter forces the output display aspect ratio to be the same
7621 of the input, by changing the output sample aspect ratio.
7623 If the input image format is different from the format requested by
7624 the next filter, the scale filter will convert the input to the
7628 The filter accepts the following options, or any of the options
7629 supported by the libswscale scaler.
7631 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
7632 the complete list of scaler options.
7637 Set the output video dimension expression. Default value is the input
7640 If the value is 0, the input width is used for the output.
7642 If one of the values is -1, the scale filter will use a value that
7643 maintains the aspect ratio of the input image, calculated from the
7644 other specified dimension. If both of them are -1, the input size is
7647 If one of the values is -n with n > 1, the scale filter will also use a value
7648 that maintains the aspect ratio of the input image, calculated from the other
7649 specified dimension. After that it will, however, make sure that the calculated
7650 dimension is divisible by n and adjust the value if necessary.
7652 See below for the list of accepted constants for use in the dimension
7656 Set the interlacing mode. It accepts the following values:
7660 Force interlaced aware scaling.
7663 Do not apply interlaced scaling.
7666 Select interlaced aware scaling depending on whether the source frames
7667 are flagged as interlaced or not.
7670 Default value is @samp{0}.
7673 Set libswscale scaling flags. See
7674 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7675 complete list of values. If not explicitly specified the filter applies
7679 Set the video size. For the syntax of this option, check the "Video size"
7680 section in the ffmpeg-utils manual.
7682 @item in_color_matrix
7683 @item out_color_matrix
7684 Set in/output YCbCr color space type.
7686 This allows the autodetected value to be overridden as well as allows forcing
7687 a specific value used for the output and encoder.
7689 If not specified, the color space type depends on the pixel format.
7695 Choose automatically.
7698 Format conforming to International Telecommunication Union (ITU)
7699 Recommendation BT.709.
7702 Set color space conforming to the United States Federal Communications
7703 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7706 Set color space conforming to:
7710 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7713 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7716 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7721 Set color space conforming to SMPTE ST 240:1999.
7726 Set in/output YCbCr sample range.
7728 This allows the autodetected value to be overridden as well as allows forcing
7729 a specific value used for the output and encoder. If not specified, the
7730 range depends on the pixel format. Possible values:
7734 Choose automatically.
7737 Set full range (0-255 in case of 8-bit luma).
7740 Set "MPEG" range (16-235 in case of 8-bit luma).
7743 @item force_original_aspect_ratio
7744 Enable decreasing or increasing output video width or height if necessary to
7745 keep the original aspect ratio. Possible values:
7749 Scale the video as specified and disable this feature.
7752 The output video dimensions will automatically be decreased if needed.
7755 The output video dimensions will automatically be increased if needed.
7759 One useful instance of this option is that when you know a specific device's
7760 maximum allowed resolution, you can use this to limit the output video to
7761 that, while retaining the aspect ratio. For example, device A allows
7762 1280x720 playback, and your video is 1920x800. Using this option (set it to
7763 decrease) and specifying 1280x720 to the command line makes the output
7766 Please note that this is a different thing than specifying -1 for @option{w}
7767 or @option{h}, you still need to specify the output resolution for this option
7772 The values of the @option{w} and @option{h} options are expressions
7773 containing the following constants:
7778 The input width and height
7782 These are the same as @var{in_w} and @var{in_h}.
7786 The output (scaled) width and height
7790 These are the same as @var{out_w} and @var{out_h}
7793 The same as @var{iw} / @var{ih}
7796 input sample aspect ratio
7799 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7803 horizontal and vertical input chroma subsample values. For example for the
7804 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7808 horizontal and vertical output chroma subsample values. For example for the
7809 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7812 @subsection Examples
7816 Scale the input video to a size of 200x100
7821 This is equivalent to:
7832 Specify a size abbreviation for the output size:
7837 which can also be written as:
7843 Scale the input to 2x:
7849 The above is the same as:
7855 Scale the input to 2x with forced interlaced scaling:
7857 scale=2*iw:2*ih:interl=1
7861 Scale the input to half size:
7867 Increase the width, and set the height to the same size:
7880 Increase the height, and set the width to 3/2 of the height:
7882 scale=w=3/2*oh:h=3/5*ih
7886 Increase the size, making the size a multiple of the chroma
7889 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7893 Increase the width to a maximum of 500 pixels,
7894 keeping the same aspect ratio as the input:
7896 scale=w='min(500\, iw*3/2):h=-1'
7900 @section separatefields
7902 The @code{separatefields} takes a frame-based video input and splits
7903 each frame into its components fields, producing a new half height clip
7904 with twice the frame rate and twice the frame count.
7906 This filter use field-dominance information in frame to decide which
7907 of each pair of fields to place first in the output.
7908 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7910 @section setdar, setsar
7912 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7915 This is done by changing the specified Sample (aka Pixel) Aspect
7916 Ratio, according to the following equation:
7918 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7921 Keep in mind that the @code{setdar} filter does not modify the pixel
7922 dimensions of the video frame. Also, the display aspect ratio set by
7923 this filter may be changed by later filters in the filterchain,
7924 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7927 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7928 the filter output video.
7930 Note that as a consequence of the application of this filter, the
7931 output display aspect ratio will change according to the equation
7934 Keep in mind that the sample aspect ratio set by the @code{setsar}
7935 filter may be changed by later filters in the filterchain, e.g. if
7936 another "setsar" or a "setdar" filter is applied.
7938 It accepts the following parameters:
7941 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7942 Set the aspect ratio used by the filter.
7944 The parameter can be a floating point number string, an expression, or
7945 a string of the form @var{num}:@var{den}, where @var{num} and
7946 @var{den} are the numerator and denominator of the aspect ratio. If
7947 the parameter is not specified, it is assumed the value "0".
7948 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7952 Set the maximum integer value to use for expressing numerator and
7953 denominator when reducing the expressed aspect ratio to a rational.
7954 Default value is @code{100}.
7958 The parameter @var{sar} is an expression containing
7959 the following constants:
7963 These are approximated values for the mathematical constants e
7964 (Euler's number), pi (Greek pi), and phi (the golden ratio).
7967 The input width and height.
7970 These are the same as @var{w} / @var{h}.
7973 The input sample aspect ratio.
7976 The input display aspect ratio. It is the same as
7977 (@var{w} / @var{h}) * @var{sar}.
7980 Horizontal and vertical chroma subsample values. For example, for the
7981 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7984 @subsection Examples
7989 To change the display aspect ratio to 16:9, specify one of the following:
7997 To change the sample aspect ratio to 10:11, specify:
8003 To set a display aspect ratio of 16:9, and specify a maximum integer value of
8004 1000 in the aspect ratio reduction, use the command:
8006 setdar=ratio=16/9:max=1000
8014 Force field for the output video frame.
8016 The @code{setfield} filter marks the interlace type field for the
8017 output frames. It does not change the input frame, but only sets the
8018 corresponding property, which affects how the frame is treated by
8019 following filters (e.g. @code{fieldorder} or @code{yadif}).
8021 The filter accepts the following options:
8026 Available values are:
8030 Keep the same field property.
8033 Mark the frame as bottom-field-first.
8036 Mark the frame as top-field-first.
8039 Mark the frame as progressive.
8045 Show a line containing various information for each input video frame.
8046 The input video is not modified.
8048 The shown line contains a sequence of key/value pairs of the form
8049 @var{key}:@var{value}.
8051 The following values are shown in the output:
8055 The (sequential) number of the input frame, starting from 0.
8058 The Presentation TimeStamp of the input frame, expressed as a number of
8059 time base units. The time base unit depends on the filter input pad.
8062 The Presentation TimeStamp of the input frame, expressed as a number of
8066 The position of the frame in the input stream, or -1 if this information is
8067 unavailable and/or meaningless (for example in case of synthetic video).
8070 The pixel format name.
8073 The sample aspect ratio of the input frame, expressed in the form
8074 @var{num}/@var{den}.
8077 The size of the input frame. For the syntax of this option, check the "Video size"
8078 section in the ffmpeg-utils manual.
8081 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
8082 for bottom field first).
8085 This is 1 if the frame is a key frame, 0 otherwise.
8088 The picture type of the input frame ("I" for an I-frame, "P" for a
8089 P-frame, "B" for a B-frame, or "?" for an unknown type).
8090 Also refer to the documentation of the @code{AVPictureType} enum and of
8091 the @code{av_get_picture_type_char} function defined in
8092 @file{libavutil/avutil.h}.
8095 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
8097 @item plane_checksum
8098 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
8099 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
8102 @section showpalette
8104 Displays the 256 colors palette of each frame. This filter is only relevant for
8105 @var{pal8} pixel format frames.
8107 It accepts the following option:
8111 Set the size of the box used to represent one palette color entry. Default is
8112 @code{30} (for a @code{30x30} pixel box).
8115 @section shuffleplanes
8117 Reorder and/or duplicate video planes.
8119 It accepts the following parameters:
8124 The index of the input plane to be used as the first output plane.
8127 The index of the input plane to be used as the second output plane.
8130 The index of the input plane to be used as the third output plane.
8133 The index of the input plane to be used as the fourth output plane.
8137 The first plane has the index 0. The default is to keep the input unchanged.
8139 Swap the second and third planes of the input:
8141 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
8144 @section signalstats
8145 Evaluate various visual metrics that assist in determining issues associated
8146 with the digitization of analog video media.
8148 By default the filter will log these metadata values:
8152 Display the minimal Y value contained within the input frame. Expressed in
8156 Display the Y value at the 10% percentile within the input frame. Expressed in
8160 Display the average Y value within the input frame. Expressed in range of
8164 Display the Y value at the 90% percentile within the input frame. Expressed in
8168 Display the maximum Y value contained within the input frame. Expressed in
8172 Display the minimal U value contained within the input frame. Expressed in
8176 Display the U value at the 10% percentile within the input frame. Expressed in
8180 Display the average U value within the input frame. Expressed in range of
8184 Display the U value at the 90% percentile within the input frame. Expressed in
8188 Display the maximum U value contained within the input frame. Expressed in
8192 Display the minimal V value contained within the input frame. Expressed in
8196 Display the V value at the 10% percentile within the input frame. Expressed in
8200 Display the average V value within the input frame. Expressed in range of
8204 Display the V value at the 90% percentile within the input frame. Expressed in
8208 Display the maximum V value contained within the input frame. Expressed in
8212 Display the minimal saturation value contained within the input frame.
8213 Expressed in range of [0-~181.02].
8216 Display the saturation value at the 10% percentile within the input frame.
8217 Expressed in range of [0-~181.02].
8220 Display the average saturation value within the input frame. Expressed in range
8224 Display the saturation value at the 90% percentile within the input frame.
8225 Expressed in range of [0-~181.02].
8228 Display the maximum saturation value contained within the input frame.
8229 Expressed in range of [0-~181.02].
8232 Display the median value for hue within the input frame. Expressed in range of
8236 Display the average value for hue within the input frame. Expressed in range of
8240 Display the average of sample value difference between all values of the Y
8241 plane in the current frame and corresponding values of the previous input frame.
8242 Expressed in range of [0-255].
8245 Display the average of sample value difference between all values of the U
8246 plane in the current frame and corresponding values of the previous input frame.
8247 Expressed in range of [0-255].
8250 Display the average of sample value difference between all values of the V
8251 plane in the current frame and corresponding values of the previous input frame.
8252 Expressed in range of [0-255].
8255 The filter accepts the following options:
8261 @option{stat} specify an additional form of image analysis.
8262 @option{out} output video with the specified type of pixel highlighted.
8264 Both options accept the following values:
8268 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
8269 unlike the neighboring pixels of the same field. Examples of temporal outliers
8270 include the results of video dropouts, head clogs, or tape tracking issues.
8273 Identify @var{vertical line repetition}. Vertical line repetition includes
8274 similar rows of pixels within a frame. In born-digital video vertical line
8275 repetition is common, but this pattern is uncommon in video digitized from an
8276 analog source. When it occurs in video that results from the digitization of an
8277 analog source it can indicate concealment from a dropout compensator.
8280 Identify pixels that fall outside of legal broadcast range.
8284 Set the highlight color for the @option{out} option. The default color is
8288 @subsection Examples
8292 Output data of various video metrics:
8294 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
8298 Output specific data about the minimum and maximum values of the Y plane per frame:
8300 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
8304 Playback video while highlighting pixels that are outside of broadcast range in red.
8306 ffplay example.mov -vf signalstats="out=brng:color=red"
8310 Playback video with signalstats metadata drawn over the frame.
8312 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
8315 The contents of signalstat_drawtext.txt used in the command are:
8318 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
8319 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
8320 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
8321 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
8329 Blur the input video without impacting the outlines.
8331 It accepts the following options:
8334 @item luma_radius, lr
8335 Set the luma radius. The option value must be a float number in
8336 the range [0.1,5.0] that specifies the variance of the gaussian filter
8337 used to blur the image (slower if larger). Default value is 1.0.
8339 @item luma_strength, ls
8340 Set the luma strength. The option value must be a float number
8341 in the range [-1.0,1.0] that configures the blurring. A value included
8342 in [0.0,1.0] will blur the image whereas a value included in
8343 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8345 @item luma_threshold, lt
8346 Set the luma threshold used as a coefficient to determine
8347 whether a pixel should be blurred or not. The option value must be an
8348 integer in the range [-30,30]. A value of 0 will filter all the image,
8349 a value included in [0,30] will filter flat areas and a value included
8350 in [-30,0] will filter edges. Default value is 0.
8352 @item chroma_radius, cr
8353 Set the chroma radius. The option value must be a float number in
8354 the range [0.1,5.0] that specifies the variance of the gaussian filter
8355 used to blur the image (slower if larger). Default value is 1.0.
8357 @item chroma_strength, cs
8358 Set the chroma strength. The option value must be a float number
8359 in the range [-1.0,1.0] that configures the blurring. A value included
8360 in [0.0,1.0] will blur the image whereas a value included in
8361 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8363 @item chroma_threshold, ct
8364 Set the chroma threshold used as a coefficient to determine
8365 whether a pixel should be blurred or not. The option value must be an
8366 integer in the range [-30,30]. A value of 0 will filter all the image,
8367 a value included in [0,30] will filter flat areas and a value included
8368 in [-30,0] will filter edges. Default value is 0.
8371 If a chroma option is not explicitly set, the corresponding luma value
8376 Convert between different stereoscopic image formats.
8378 The filters accept the following options:
8382 Set stereoscopic image format of input.
8384 Available values for input image formats are:
8387 side by side parallel (left eye left, right eye right)
8390 side by side crosseye (right eye left, left eye right)
8393 side by side parallel with half width resolution
8394 (left eye left, right eye right)
8397 side by side crosseye with half width resolution
8398 (right eye left, left eye right)
8401 above-below (left eye above, right eye below)
8404 above-below (right eye above, left eye below)
8407 above-below with half height resolution
8408 (left eye above, right eye below)
8411 above-below with half height resolution
8412 (right eye above, left eye below)
8415 alternating frames (left eye first, right eye second)
8418 alternating frames (right eye first, left eye second)
8420 Default value is @samp{sbsl}.
8424 Set stereoscopic image format of output.
8426 Available values for output image formats are all the input formats as well as:
8429 anaglyph red/blue gray
8430 (red filter on left eye, blue filter on right eye)
8433 anaglyph red/green gray
8434 (red filter on left eye, green filter on right eye)
8437 anaglyph red/cyan gray
8438 (red filter on left eye, cyan filter on right eye)
8441 anaglyph red/cyan half colored
8442 (red filter on left eye, cyan filter on right eye)
8445 anaglyph red/cyan color
8446 (red filter on left eye, cyan filter on right eye)
8449 anaglyph red/cyan color optimized with the least squares projection of dubois
8450 (red filter on left eye, cyan filter on right eye)
8453 anaglyph green/magenta gray
8454 (green filter on left eye, magenta filter on right eye)
8457 anaglyph green/magenta half colored
8458 (green filter on left eye, magenta filter on right eye)
8461 anaglyph green/magenta colored
8462 (green filter on left eye, magenta filter on right eye)
8465 anaglyph green/magenta color optimized with the least squares projection of dubois
8466 (green filter on left eye, magenta filter on right eye)
8469 anaglyph yellow/blue gray
8470 (yellow filter on left eye, blue filter on right eye)
8473 anaglyph yellow/blue half colored
8474 (yellow filter on left eye, blue filter on right eye)
8477 anaglyph yellow/blue colored
8478 (yellow filter on left eye, blue filter on right eye)
8481 anaglyph yellow/blue color optimized with the least squares projection of dubois
8482 (yellow filter on left eye, blue filter on right eye)
8485 interleaved rows (left eye has top row, right eye starts on next row)
8488 interleaved rows (right eye has top row, left eye starts on next row)
8491 mono output (left eye only)
8494 mono output (right eye only)
8497 Default value is @samp{arcd}.
8500 @subsection Examples
8504 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
8510 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
8519 Apply a simple postprocessing filter that compresses and decompresses the image
8520 at several (or - in the case of @option{quality} level @code{6} - all) shifts
8521 and average the results.
8523 The filter accepts the following options:
8527 Set quality. This option defines the number of levels for averaging. It accepts
8528 an integer in the range 0-6. If set to @code{0}, the filter will have no
8529 effect. A value of @code{6} means the higher quality. For each increment of
8530 that value the speed drops by a factor of approximately 2. Default value is
8534 Force a constant quantization parameter. If not set, the filter will use the QP
8535 from the video stream (if available).
8538 Set thresholding mode. Available modes are:
8542 Set hard thresholding (default).
8544 Set soft thresholding (better de-ringing effect, but likely blurrier).
8548 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8549 option may cause flicker since the B-Frames have often larger QP. Default is
8550 @code{0} (not enabled).
8556 Draw subtitles on top of input video using the libass library.
8558 To enable compilation of this filter you need to configure FFmpeg with
8559 @code{--enable-libass}. This filter also requires a build with libavcodec and
8560 libavformat to convert the passed subtitles file to ASS (Advanced Substation
8561 Alpha) subtitles format.
8563 The filter accepts the following options:
8567 Set the filename of the subtitle file to read. It must be specified.
8570 Specify the size of the original video, the video for which the ASS file
8571 was composed. For the syntax of this option, check the "Video size" section in
8572 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
8573 this is necessary to correctly scale the fonts if the aspect ratio has been
8577 Set subtitles input character encoding. @code{subtitles} filter only. Only
8578 useful if not UTF-8.
8580 @item stream_index, si
8581 Set subtitles stream index. @code{subtitles} filter only.
8584 If the first key is not specified, it is assumed that the first value
8585 specifies the @option{filename}.
8587 For example, to render the file @file{sub.srt} on top of the input
8588 video, use the command:
8593 which is equivalent to:
8595 subtitles=filename=sub.srt
8598 To render the default subtitles stream from file @file{video.mkv}, use:
8603 To render the second subtitles stream from that file, use:
8605 subtitles=video.mkv:si=1
8610 Scale the input by 2x and smooth using the Super2xSaI (Scale and
8611 Interpolate) pixel art scaling algorithm.
8613 Useful for enlarging pixel art images without reducing sharpness.
8620 Apply telecine process to the video.
8622 This filter accepts the following options:
8631 The default value is @code{top}.
8635 A string of numbers representing the pulldown pattern you wish to apply.
8636 The default value is @code{23}.
8640 Some typical patterns:
8645 24p: 2332 (preferred)
8652 24p: 222222222223 ("Euro pulldown")
8658 Select the most representative frame in a given sequence of consecutive frames.
8660 The filter accepts the following options:
8664 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
8665 will pick one of them, and then handle the next batch of @var{n} frames until
8666 the end. Default is @code{100}.
8669 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
8670 value will result in a higher memory usage, so a high value is not recommended.
8672 @subsection Examples
8676 Extract one picture each 50 frames:
8682 Complete example of a thumbnail creation with @command{ffmpeg}:
8684 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
8690 Tile several successive frames together.
8692 The filter accepts the following options:
8697 Set the grid size (i.e. the number of lines and columns). For the syntax of
8698 this option, check the "Video size" section in the ffmpeg-utils manual.
8701 Set the maximum number of frames to render in the given area. It must be less
8702 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
8703 the area will be used.
8706 Set the outer border margin in pixels.
8709 Set the inner border thickness (i.e. the number of pixels between frames). For
8710 more advanced padding options (such as having different values for the edges),
8711 refer to the pad video filter.
8714 Specify the color of the unused area. For the syntax of this option, check the
8715 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
8719 @subsection Examples
8723 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
8725 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
8727 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
8728 duplicating each output frame to accommodate the originally detected frame
8732 Display @code{5} pictures in an area of @code{3x2} frames,
8733 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
8734 mixed flat and named options:
8736 tile=3x2:nb_frames=5:padding=7:margin=2
8742 Perform various types of temporal field interlacing.
8744 Frames are counted starting from 1, so the first input frame is
8747 The filter accepts the following options:
8752 Specify the mode of the interlacing. This option can also be specified
8753 as a value alone. See below for a list of values for this option.
8755 Available values are:
8759 Move odd frames into the upper field, even into the lower field,
8760 generating a double height frame at half frame rate.
8764 Frame 1 Frame 2 Frame 3 Frame 4
8766 11111 22222 33333 44444
8767 11111 22222 33333 44444
8768 11111 22222 33333 44444
8769 11111 22222 33333 44444
8783 Only output even frames, odd frames are dropped, generating a frame with
8784 unchanged height at half frame rate.
8789 Frame 1 Frame 2 Frame 3 Frame 4
8791 11111 22222 33333 44444
8792 11111 22222 33333 44444
8793 11111 22222 33333 44444
8794 11111 22222 33333 44444
8804 Only output odd frames, even frames are dropped, generating a frame with
8805 unchanged height at half frame rate.
8810 Frame 1 Frame 2 Frame 3 Frame 4
8812 11111 22222 33333 44444
8813 11111 22222 33333 44444
8814 11111 22222 33333 44444
8815 11111 22222 33333 44444
8825 Expand each frame to full height, but pad alternate lines with black,
8826 generating a frame with double height at the same input frame rate.
8831 Frame 1 Frame 2 Frame 3 Frame 4
8833 11111 22222 33333 44444
8834 11111 22222 33333 44444
8835 11111 22222 33333 44444
8836 11111 22222 33333 44444
8839 11111 ..... 33333 .....
8840 ..... 22222 ..... 44444
8841 11111 ..... 33333 .....
8842 ..... 22222 ..... 44444
8843 11111 ..... 33333 .....
8844 ..... 22222 ..... 44444
8845 11111 ..... 33333 .....
8846 ..... 22222 ..... 44444
8850 @item interleave_top, 4
8851 Interleave the upper field from odd frames with the lower field from
8852 even frames, generating a frame with unchanged height at half frame rate.
8857 Frame 1 Frame 2 Frame 3 Frame 4
8859 11111<- 22222 33333<- 44444
8860 11111 22222<- 33333 44444<-
8861 11111<- 22222 33333<- 44444
8862 11111 22222<- 33333 44444<-
8872 @item interleave_bottom, 5
8873 Interleave the lower field from odd frames with the upper field from
8874 even frames, generating a frame with unchanged height at half frame rate.
8879 Frame 1 Frame 2 Frame 3 Frame 4
8881 11111 22222<- 33333 44444<-
8882 11111<- 22222 33333<- 44444
8883 11111 22222<- 33333 44444<-
8884 11111<- 22222 33333<- 44444
8894 @item interlacex2, 6
8895 Double frame rate with unchanged height. Frames are inserted each
8896 containing the second temporal field from the previous input frame and
8897 the first temporal field from the next input frame. This mode relies on
8898 the top_field_first flag. Useful for interlaced video displays with no
8899 field synchronisation.
8904 Frame 1 Frame 2 Frame 3 Frame 4
8906 11111 22222 33333 44444
8907 11111 22222 33333 44444
8908 11111 22222 33333 44444
8909 11111 22222 33333 44444
8912 11111 22222 22222 33333 33333 44444 44444
8913 11111 11111 22222 22222 33333 33333 44444
8914 11111 22222 22222 33333 33333 44444 44444
8915 11111 11111 22222 22222 33333 33333 44444
8921 Numeric values are deprecated but are accepted for backward
8922 compatibility reasons.
8924 Default mode is @code{merge}.
8927 Specify flags influencing the filter process.
8929 Available value for @var{flags} is:
8932 @item low_pass_filter, vlfp
8933 Enable vertical low-pass filtering in the filter.
8934 Vertical low-pass filtering is required when creating an interlaced
8935 destination from a progressive source which contains high-frequency
8936 vertical detail. Filtering will reduce interlace 'twitter' and Moire
8939 Vertical low-pass filtering can only be enabled for @option{mode}
8940 @var{interleave_top} and @var{interleave_bottom}.
8947 Transpose rows with columns in the input video and optionally flip it.
8949 It accepts the following parameters:
8954 Specify the transposition direction.
8956 Can assume the following values:
8958 @item 0, 4, cclock_flip
8959 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
8967 Rotate by 90 degrees clockwise, that is:
8975 Rotate by 90 degrees counterclockwise, that is:
8982 @item 3, 7, clock_flip
8983 Rotate by 90 degrees clockwise and vertically flip, that is:
8991 For values between 4-7, the transposition is only done if the input
8992 video geometry is portrait and not landscape. These values are
8993 deprecated, the @code{passthrough} option should be used instead.
8995 Numerical values are deprecated, and should be dropped in favor of
8999 Do not apply the transposition if the input geometry matches the one
9000 specified by the specified value. It accepts the following values:
9003 Always apply transposition.
9005 Preserve portrait geometry (when @var{height} >= @var{width}).
9007 Preserve landscape geometry (when @var{width} >= @var{height}).
9010 Default value is @code{none}.
9013 For example to rotate by 90 degrees clockwise and preserve portrait
9016 transpose=dir=1:passthrough=portrait
9019 The command above can also be specified as:
9021 transpose=1:portrait
9025 Trim the input so that the output contains one continuous subpart of the input.
9027 It accepts the following parameters:
9030 Specify the time of the start of the kept section, i.e. the frame with the
9031 timestamp @var{start} will be the first frame in the output.
9034 Specify the time of the first frame that will be dropped, i.e. the frame
9035 immediately preceding the one with the timestamp @var{end} will be the last
9036 frame in the output.
9039 This is the same as @var{start}, except this option sets the start timestamp
9040 in timebase units instead of seconds.
9043 This is the same as @var{end}, except this option sets the end timestamp
9044 in timebase units instead of seconds.
9047 The maximum duration of the output in seconds.
9050 The number of the first frame that should be passed to the output.
9053 The number of the first frame that should be dropped.
9056 @option{start}, @option{end}, and @option{duration} are expressed as time
9057 duration specifications; see
9058 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
9059 for the accepted syntax.
9061 Note that the first two sets of the start/end options and the @option{duration}
9062 option look at the frame timestamp, while the _frame variants simply count the
9063 frames that pass through the filter. Also note that this filter does not modify
9064 the timestamps. If you wish for the output timestamps to start at zero, insert a
9065 setpts filter after the trim filter.
9067 If multiple start or end options are set, this filter tries to be greedy and
9068 keep all the frames that match at least one of the specified constraints. To keep
9069 only the part that matches all the constraints at once, chain multiple trim
9072 The defaults are such that all the input is kept. So it is possible to set e.g.
9073 just the end values to keep everything before the specified time.
9078 Drop everything except the second minute of input:
9080 ffmpeg -i INPUT -vf trim=60:120
9084 Keep only the first second:
9086 ffmpeg -i INPUT -vf trim=duration=1
9095 Sharpen or blur the input video.
9097 It accepts the following parameters:
9100 @item luma_msize_x, lx
9101 Set the luma matrix horizontal size. It must be an odd integer between
9102 3 and 63. The default value is 5.
9104 @item luma_msize_y, ly
9105 Set the luma matrix vertical size. It must be an odd integer between 3
9106 and 63. The default value is 5.
9108 @item luma_amount, la
9109 Set the luma effect strength. It must be a floating point number, reasonable
9110 values lay between -1.5 and 1.5.
9112 Negative values will blur the input video, while positive values will
9113 sharpen it, a value of zero will disable the effect.
9115 Default value is 1.0.
9117 @item chroma_msize_x, cx
9118 Set the chroma matrix horizontal size. It must be an odd integer
9119 between 3 and 63. The default value is 5.
9121 @item chroma_msize_y, cy
9122 Set the chroma matrix vertical size. It must be an odd integer
9123 between 3 and 63. The default value is 5.
9125 @item chroma_amount, ca
9126 Set the chroma effect strength. It must be a floating point number, reasonable
9127 values lay between -1.5 and 1.5.
9129 Negative values will blur the input video, while positive values will
9130 sharpen it, a value of zero will disable the effect.
9132 Default value is 0.0.
9135 If set to 1, specify using OpenCL capabilities, only available if
9136 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
9140 All parameters are optional and default to the equivalent of the
9141 string '5:5:1.0:5:5:0.0'.
9143 @subsection Examples
9147 Apply strong luma sharpen effect:
9149 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
9153 Apply a strong blur of both luma and chroma parameters:
9155 unsharp=7:7:-2:7:7:-2
9161 Apply ultra slow/simple postprocessing filter that compresses and decompresses
9162 the image at several (or - in the case of @option{quality} level @code{8} - all)
9163 shifts and average the results.
9165 The way this differs from the behavior of spp is that uspp actually encodes &
9166 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
9167 DCT similar to MJPEG.
9169 The filter accepts the following options:
9173 Set quality. This option defines the number of levels for averaging. It accepts
9174 an integer in the range 0-8. If set to @code{0}, the filter will have no
9175 effect. A value of @code{8} means the higher quality. For each increment of
9176 that value the speed drops by a factor of approximately 2. Default value is
9180 Force a constant quantization parameter. If not set, the filter will use the QP
9181 from the video stream (if available).
9184 @anchor{vidstabdetect}
9185 @section vidstabdetect
9187 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
9188 @ref{vidstabtransform} for pass 2.
9190 This filter generates a file with relative translation and rotation
9191 transform information about subsequent frames, which is then used by
9192 the @ref{vidstabtransform} filter.
9194 To enable compilation of this filter you need to configure FFmpeg with
9195 @code{--enable-libvidstab}.
9197 This filter accepts the following options:
9201 Set the path to the file used to write the transforms information.
9202 Default value is @file{transforms.trf}.
9205 Set how shaky the video is and how quick the camera is. It accepts an
9206 integer in the range 1-10, a value of 1 means little shakiness, a
9207 value of 10 means strong shakiness. Default value is 5.
9210 Set the accuracy of the detection process. It must be a value in the
9211 range 1-15. A value of 1 means low accuracy, a value of 15 means high
9212 accuracy. Default value is 15.
9215 Set stepsize of the search process. The region around minimum is
9216 scanned with 1 pixel resolution. Default value is 6.
9219 Set minimum contrast. Below this value a local measurement field is
9220 discarded. Must be a floating point value in the range 0-1. Default
9224 Set reference frame number for tripod mode.
9226 If enabled, the motion of the frames is compared to a reference frame
9227 in the filtered stream, identified by the specified number. The idea
9228 is to compensate all movements in a more-or-less static scene and keep
9229 the camera view absolutely still.
9231 If set to 0, it is disabled. The frames are counted starting from 1.
9234 Show fields and transforms in the resulting frames. It accepts an
9235 integer in the range 0-2. Default value is 0, which disables any
9239 @subsection Examples
9249 Analyze strongly shaky movie and put the results in file
9250 @file{mytransforms.trf}:
9252 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
9256 Visualize the result of internal transformations in the resulting
9259 vidstabdetect=show=1
9263 Analyze a video with medium shakiness using @command{ffmpeg}:
9265 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
9269 @anchor{vidstabtransform}
9270 @section vidstabtransform
9272 Video stabilization/deshaking: pass 2 of 2,
9273 see @ref{vidstabdetect} for pass 1.
9275 Read a file with transform information for each frame and
9276 apply/compensate them. Together with the @ref{vidstabdetect}
9277 filter this can be used to deshake videos. See also
9278 @url{http://public.hronopik.de/vid.stab}. It is important to also use
9279 the @ref{unsharp} filter, see below.
9281 To enable compilation of this filter you need to configure FFmpeg with
9282 @code{--enable-libvidstab}.
9288 Set path to the file used to read the transforms. Default value is
9289 @file{transforms.trf}.
9292 Set the number of frames (value*2 + 1) used for lowpass filtering the
9293 camera movements. Default value is 10.
9295 For example a number of 10 means that 21 frames are used (10 in the
9296 past and 10 in the future) to smoothen the motion in the video. A
9297 larger value leads to a smoother video, but limits the acceleration of
9298 the camera (pan/tilt movements). 0 is a special case where a static
9299 camera is simulated.
9302 Set the camera path optimization algorithm.
9304 Accepted values are:
9307 gaussian kernel low-pass filter on camera motion (default)
9309 averaging on transformations
9313 Set maximal number of pixels to translate frames. Default value is -1,
9317 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
9318 value is -1, meaning no limit.
9321 Specify how to deal with borders that may be visible due to movement
9324 Available values are:
9327 keep image information from previous frame (default)
9329 fill the border black
9333 Invert transforms if set to 1. Default value is 0.
9336 Consider transforms as relative to previous frame if set to 1,
9337 absolute if set to 0. Default value is 0.
9340 Set percentage to zoom. A positive value will result in a zoom-in
9341 effect, a negative value in a zoom-out effect. Default value is 0 (no
9345 Set optimal zooming to avoid borders.
9347 Accepted values are:
9352 optimal static zoom value is determined (only very strong movements
9353 will lead to visible borders) (default)
9355 optimal adaptive zoom value is determined (no borders will be
9356 visible), see @option{zoomspeed}
9359 Note that the value given at zoom is added to the one calculated here.
9362 Set percent to zoom maximally each frame (enabled when
9363 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
9367 Specify type of interpolation.
9369 Available values are:
9374 linear only horizontal
9376 linear in both directions (default)
9378 cubic in both directions (slow)
9382 Enable virtual tripod mode if set to 1, which is equivalent to
9383 @code{relative=0:smoothing=0}. Default value is 0.
9385 Use also @code{tripod} option of @ref{vidstabdetect}.
9388 Increase log verbosity if set to 1. Also the detected global motions
9389 are written to the temporary file @file{global_motions.trf}. Default
9393 @subsection Examples
9397 Use @command{ffmpeg} for a typical stabilization with default values:
9399 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
9402 Note the use of the @ref{unsharp} filter which is always recommended.
9405 Zoom in a bit more and load transform data from a given file:
9407 vidstabtransform=zoom=5:input="mytransforms.trf"
9411 Smoothen the video even more:
9413 vidstabtransform=smoothing=30
9419 Flip the input video vertically.
9421 For example, to vertically flip a video with @command{ffmpeg}:
9423 ffmpeg -i in.avi -vf "vflip" out.avi
9429 Make or reverse a natural vignetting effect.
9431 The filter accepts the following options:
9435 Set lens angle expression as a number of radians.
9437 The value is clipped in the @code{[0,PI/2]} range.
9439 Default value: @code{"PI/5"}
9443 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
9447 Set forward/backward mode.
9449 Available modes are:
9452 The larger the distance from the central point, the darker the image becomes.
9455 The larger the distance from the central point, the brighter the image becomes.
9456 This can be used to reverse a vignette effect, though there is no automatic
9457 detection to extract the lens @option{angle} and other settings (yet). It can
9458 also be used to create a burning effect.
9461 Default value is @samp{forward}.
9464 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
9466 It accepts the following values:
9469 Evaluate expressions only once during the filter initialization.
9472 Evaluate expressions for each incoming frame. This is way slower than the
9473 @samp{init} mode since it requires all the scalers to be re-computed, but it
9474 allows advanced dynamic expressions.
9477 Default value is @samp{init}.
9480 Set dithering to reduce the circular banding effects. Default is @code{1}
9484 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
9485 Setting this value to the SAR of the input will make a rectangular vignetting
9486 following the dimensions of the video.
9488 Default is @code{1/1}.
9491 @subsection Expressions
9493 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
9494 following parameters.
9499 input width and height
9502 the number of input frame, starting from 0
9505 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
9506 @var{TB} units, NAN if undefined
9509 frame rate of the input video, NAN if the input frame rate is unknown
9512 the PTS (Presentation TimeStamp) of the filtered video frame,
9513 expressed in seconds, NAN if undefined
9516 time base of the input video
9520 @subsection Examples
9524 Apply simple strong vignetting effect:
9530 Make a flickering vignetting:
9532 vignette='PI/4+random(1)*PI/50':eval=frame
9539 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
9540 Deinterlacing Filter").
9542 Based on the process described by Martin Weston for BBC R&D, and
9543 implemented based on the de-interlace algorithm written by Jim
9544 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
9545 uses filter coefficients calculated by BBC R&D.
9547 There are two sets of filter coefficients, so called "simple":
9548 and "complex". Which set of filter coefficients is used can
9549 be set by passing an optional parameter:
9553 Set the interlacing filter coefficients. Accepts one of the following values:
9557 Simple filter coefficient set.
9559 More-complex filter coefficient set.
9561 Default value is @samp{complex}.
9564 Specify which frames to deinterlace. Accept one of the following values:
9568 Deinterlace all frames,
9570 Only deinterlace frames marked as interlaced.
9573 Default value is @samp{all}.
9577 Apply the xBR high-quality magnification filter which is designed for pixel
9578 art. It follows a set of edge-detection rules, see
9579 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
9581 It accepts the following option:
9585 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
9586 @code{3xBR} and @code{4} for @code{4xBR}.
9587 Default is @code{3}.
9593 Deinterlace the input video ("yadif" means "yet another deinterlacing
9596 It accepts the following parameters:
9602 The interlacing mode to adopt. It accepts one of the following values:
9606 Output one frame for each frame.
9608 Output one frame for each field.
9609 @item 2, send_frame_nospatial
9610 Like @code{send_frame}, but it skips the spatial interlacing check.
9611 @item 3, send_field_nospatial
9612 Like @code{send_field}, but it skips the spatial interlacing check.
9615 The default value is @code{send_frame}.
9618 The picture field parity assumed for the input interlaced video. It accepts one
9619 of the following values:
9623 Assume the top field is first.
9625 Assume the bottom field is first.
9627 Enable automatic detection of field parity.
9630 The default value is @code{auto}.
9631 If the interlacing is unknown or the decoder does not export this information,
9632 top field first will be assumed.
9635 Specify which frames to deinterlace. Accept one of the following
9640 Deinterlace all frames.
9642 Only deinterlace frames marked as interlaced.
9645 The default value is @code{all}.
9650 Apply Zoom & Pan effect.
9652 This filter accepts the following options:
9656 Set the zoom expression. Default is 1.
9660 Set the x and y expression. Default is 0.
9663 Set the duration expression in number of frames.
9664 This sets for how many number of frames effect will last for
9668 Set the output image size, default is 'hd720'.
9671 Each expression can contain the following constants:
9694 Last calculated 'x' and 'y' position from 'x' and 'y' expression
9695 for current input frame.
9699 'x' and 'y' of last output frame of previous input frame or 0 when there was
9700 not yet such frame (first input frame).
9703 Last calculated zoom from 'z' expression for current input frame.
9706 Last calculated zoom of last output frame of previous input frame.
9709 Number of output frames for current input frame. Calculated from 'd' expression
9710 for each input frame.
9713 number of output frames created for previous input frame
9716 Rational number: input width / input height
9722 display aspect ratio
9726 @subsection Examples
9730 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
9732 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
9736 @c man end VIDEO FILTERS
9738 @chapter Video Sources
9739 @c man begin VIDEO SOURCES
9741 Below is a description of the currently available video sources.
9745 Buffer video frames, and make them available to the filter chain.
9747 This source is mainly intended for a programmatic use, in particular
9748 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
9750 It accepts the following parameters:
9755 Specify the size (width and height) of the buffered video frames. For the
9756 syntax of this option, check the "Video size" section in the ffmpeg-utils
9760 The input video width.
9763 The input video height.
9766 A string representing the pixel format of the buffered video frames.
9767 It may be a number corresponding to a pixel format, or a pixel format
9771 Specify the timebase assumed by the timestamps of the buffered frames.
9774 Specify the frame rate expected for the video stream.
9776 @item pixel_aspect, sar
9777 The sample (pixel) aspect ratio of the input video.
9780 Specify the optional parameters to be used for the scale filter which
9781 is automatically inserted when an input change is detected in the
9782 input size or format.
9787 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
9790 will instruct the source to accept video frames with size 320x240 and
9791 with format "yuv410p", assuming 1/24 as the timestamps timebase and
9792 square pixels (1:1 sample aspect ratio).
9793 Since the pixel format with name "yuv410p" corresponds to the number 6
9794 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
9795 this example corresponds to:
9797 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
9800 Alternatively, the options can be specified as a flat string, but this
9801 syntax is deprecated:
9803 @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}]
9807 Create a pattern generated by an elementary cellular automaton.
9809 The initial state of the cellular automaton can be defined through the
9810 @option{filename}, and @option{pattern} options. If such options are
9811 not specified an initial state is created randomly.
9813 At each new frame a new row in the video is filled with the result of
9814 the cellular automaton next generation. The behavior when the whole
9815 frame is filled is defined by the @option{scroll} option.
9817 This source accepts the following options:
9821 Read the initial cellular automaton state, i.e. the starting row, from
9823 In the file, each non-whitespace character is considered an alive
9824 cell, a newline will terminate the row, and further characters in the
9825 file will be ignored.
9828 Read the initial cellular automaton state, i.e. the starting row, from
9829 the specified string.
9831 Each non-whitespace character in the string is considered an alive
9832 cell, a newline will terminate the row, and further characters in the
9833 string will be ignored.
9836 Set the video rate, that is the number of frames generated per second.
9839 @item random_fill_ratio, ratio
9840 Set the random fill ratio for the initial cellular automaton row. It
9841 is a floating point number value ranging from 0 to 1, defaults to
9844 This option is ignored when a file or a pattern is specified.
9846 @item random_seed, seed
9847 Set the seed for filling randomly the initial row, must be an integer
9848 included between 0 and UINT32_MAX. If not specified, or if explicitly
9849 set to -1, the filter will try to use a good random seed on a best
9853 Set the cellular automaton rule, it is a number ranging from 0 to 255.
9854 Default value is 110.
9857 Set the size of the output video. For the syntax of this option, check
9858 the "Video size" section in the ffmpeg-utils manual.
9860 If @option{filename} or @option{pattern} is specified, the size is set
9861 by default to the width of the specified initial state row, and the
9862 height is set to @var{width} * PHI.
9864 If @option{size} is set, it must contain the width of the specified
9865 pattern string, and the specified pattern will be centered in the
9868 If a filename or a pattern string is not specified, the size value
9869 defaults to "320x518" (used for a randomly generated initial state).
9872 If set to 1, scroll the output upward when all the rows in the output
9873 have been already filled. If set to 0, the new generated row will be
9874 written over the top row just after the bottom row is filled.
9877 @item start_full, full
9878 If set to 1, completely fill the output with generated rows before
9879 outputting the first frame.
9880 This is the default behavior, for disabling set the value to 0.
9883 If set to 1, stitch the left and right row edges together.
9884 This is the default behavior, for disabling set the value to 0.
9887 @subsection Examples
9891 Read the initial state from @file{pattern}, and specify an output of
9894 cellauto=f=pattern:s=200x400
9898 Generate a random initial row with a width of 200 cells, with a fill
9901 cellauto=ratio=2/3:s=200x200
9905 Create a pattern generated by rule 18 starting by a single alive cell
9906 centered on an initial row with width 100:
9908 cellauto=p=@@:s=100x400:full=0:rule=18
9912 Specify a more elaborated initial pattern:
9914 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
9921 Generate a Mandelbrot set fractal, and progressively zoom towards the
9922 point specified with @var{start_x} and @var{start_y}.
9924 This source accepts the following options:
9929 Set the terminal pts value. Default value is 400.
9932 Set the terminal scale value.
9933 Must be a floating point value. Default value is 0.3.
9936 Set the inner coloring mode, that is the algorithm used to draw the
9937 Mandelbrot fractal internal region.
9939 It shall assume one of the following values:
9944 Show time until convergence.
9946 Set color based on point closest to the origin of the iterations.
9951 Default value is @var{mincol}.
9954 Set the bailout value. Default value is 10.0.
9957 Set the maximum of iterations performed by the rendering
9958 algorithm. Default value is 7189.
9961 Set outer coloring mode.
9962 It shall assume one of following values:
9964 @item iteration_count
9965 Set iteration cound mode.
9966 @item normalized_iteration_count
9967 set normalized iteration count mode.
9969 Default value is @var{normalized_iteration_count}.
9972 Set frame rate, expressed as number of frames per second. Default
9976 Set frame size. For the syntax of this option, check the "Video
9977 size" section in the ffmpeg-utils manual. Default value is "640x480".
9980 Set the initial scale value. Default value is 3.0.
9983 Set the initial x position. Must be a floating point value between
9984 -100 and 100. Default value is -0.743643887037158704752191506114774.
9987 Set the initial y position. Must be a floating point value between
9988 -100 and 100. Default value is -0.131825904205311970493132056385139.
9993 Generate various test patterns, as generated by the MPlayer test filter.
9995 The size of the generated video is fixed, and is 256x256.
9996 This source is useful in particular for testing encoding features.
9998 This source accepts the following options:
10003 Specify the frame rate of the sourced video, as the number of frames
10004 generated per second. It has to be a string in the format
10005 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
10006 number or a valid video frame rate abbreviation. The default value is
10010 Set the duration of the sourced video. See
10011 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
10012 for the accepted syntax.
10014 If not specified, or the expressed duration is negative, the video is
10015 supposed to be generated forever.
10019 Set the number or the name of the test to perform. Supported tests are:
10035 Default value is "all", which will cycle through the list of all tests.
10040 mptestsrc=t=dc_luma
10043 will generate a "dc_luma" test pattern.
10045 @section frei0r_src
10047 Provide a frei0r source.
10049 To enable compilation of this filter you need to install the frei0r
10050 header and configure FFmpeg with @code{--enable-frei0r}.
10052 This source accepts the following parameters:
10057 The size of the video to generate. For the syntax of this option, check the
10058 "Video size" section in the ffmpeg-utils manual.
10061 The framerate of the generated video. It may be a string of the form
10062 @var{num}/@var{den} or a frame rate abbreviation.
10065 The name to the frei0r source to load. For more information regarding frei0r and
10066 how to set the parameters, read the @ref{frei0r} section in the video filters
10069 @item filter_params
10070 A '|'-separated list of parameters to pass to the frei0r source.
10074 For example, to generate a frei0r partik0l source with size 200x200
10075 and frame rate 10 which is overlaid on the overlay filter main input:
10077 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
10082 Generate a life pattern.
10084 This source is based on a generalization of John Conway's life game.
10086 The sourced input represents a life grid, each pixel represents a cell
10087 which can be in one of two possible states, alive or dead. Every cell
10088 interacts with its eight neighbours, which are the cells that are
10089 horizontally, vertically, or diagonally adjacent.
10091 At each interaction the grid evolves according to the adopted rule,
10092 which specifies the number of neighbor alive cells which will make a
10093 cell stay alive or born. The @option{rule} option allows one to specify
10096 This source accepts the following options:
10100 Set the file from which to read the initial grid state. In the file,
10101 each non-whitespace character is considered an alive cell, and newline
10102 is used to delimit the end of each row.
10104 If this option is not specified, the initial grid is generated
10108 Set the video rate, that is the number of frames generated per second.
10111 @item random_fill_ratio, ratio
10112 Set the random fill ratio for the initial random grid. It is a
10113 floating point number value ranging from 0 to 1, defaults to 1/PHI.
10114 It is ignored when a file is specified.
10116 @item random_seed, seed
10117 Set the seed for filling the initial random grid, must be an integer
10118 included between 0 and UINT32_MAX. If not specified, or if explicitly
10119 set to -1, the filter will try to use a good random seed on a best
10125 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
10126 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
10127 @var{NS} specifies the number of alive neighbor cells which make a
10128 live cell stay alive, and @var{NB} the number of alive neighbor cells
10129 which make a dead cell to become alive (i.e. to "born").
10130 "s" and "b" can be used in place of "S" and "B", respectively.
10132 Alternatively a rule can be specified by an 18-bits integer. The 9
10133 high order bits are used to encode the next cell state if it is alive
10134 for each number of neighbor alive cells, the low order bits specify
10135 the rule for "borning" new cells. Higher order bits encode for an
10136 higher number of neighbor cells.
10137 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
10138 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
10140 Default value is "S23/B3", which is the original Conway's game of life
10141 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
10142 cells, and will born a new cell if there are three alive cells around
10146 Set the size of the output video. For the syntax of this option, check the
10147 "Video size" section in the ffmpeg-utils manual.
10149 If @option{filename} is specified, the size is set by default to the
10150 same size of the input file. If @option{size} is set, it must contain
10151 the size specified in the input file, and the initial grid defined in
10152 that file is centered in the larger resulting area.
10154 If a filename is not specified, the size value defaults to "320x240"
10155 (used for a randomly generated initial grid).
10158 If set to 1, stitch the left and right grid edges together, and the
10159 top and bottom edges also. Defaults to 1.
10162 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
10163 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
10164 value from 0 to 255.
10167 Set the color of living (or new born) cells.
10170 Set the color of dead cells. If @option{mold} is set, this is the first color
10171 used to represent a dead cell.
10174 Set mold color, for definitely dead and moldy cells.
10176 For the syntax of these 3 color options, check the "Color" section in the
10177 ffmpeg-utils manual.
10180 @subsection Examples
10184 Read a grid from @file{pattern}, and center it on a grid of size
10187 life=f=pattern:s=300x300
10191 Generate a random grid of size 200x200, with a fill ratio of 2/3:
10193 life=ratio=2/3:s=200x200
10197 Specify a custom rule for evolving a randomly generated grid:
10203 Full example with slow death effect (mold) using @command{ffplay}:
10205 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
10210 @anchor{haldclutsrc}
10212 @anchor{rgbtestsrc}
10214 @anchor{smptehdbars}
10216 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
10218 The @code{color} source provides an uniformly colored input.
10220 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
10221 @ref{haldclut} filter.
10223 The @code{nullsrc} source returns unprocessed video frames. It is
10224 mainly useful to be employed in analysis / debugging tools, or as the
10225 source for filters which ignore the input data.
10227 The @code{rgbtestsrc} source generates an RGB test pattern useful for
10228 detecting RGB vs BGR issues. You should see a red, green and blue
10229 stripe from top to bottom.
10231 The @code{smptebars} source generates a color bars pattern, based on
10232 the SMPTE Engineering Guideline EG 1-1990.
10234 The @code{smptehdbars} source generates a color bars pattern, based on
10235 the SMPTE RP 219-2002.
10237 The @code{testsrc} source generates a test video pattern, showing a
10238 color pattern, a scrolling gradient and a timestamp. This is mainly
10239 intended for testing purposes.
10241 The sources accept the following parameters:
10246 Specify the color of the source, only available in the @code{color}
10247 source. For the syntax of this option, check the "Color" section in the
10248 ffmpeg-utils manual.
10251 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
10252 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
10253 pixels to be used as identity matrix for 3D lookup tables. Each component is
10254 coded on a @code{1/(N*N)} scale.
10257 Specify the size of the sourced video. For the syntax of this option, check the
10258 "Video size" section in the ffmpeg-utils manual. The default value is
10261 This option is not available with the @code{haldclutsrc} filter.
10264 Specify the frame rate of the sourced video, as the number of frames
10265 generated per second. It has to be a string in the format
10266 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
10267 number or a valid video frame rate abbreviation. The default value is
10271 Set the sample aspect ratio of the sourced video.
10274 Set the duration of the sourced video. See
10275 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
10276 for the accepted syntax.
10278 If not specified, or the expressed duration is negative, the video is
10279 supposed to be generated forever.
10282 Set the number of decimals to show in the timestamp, only available in the
10283 @code{testsrc} source.
10285 The displayed timestamp value will correspond to the original
10286 timestamp value multiplied by the power of 10 of the specified
10287 value. Default value is 0.
10290 For example the following:
10292 testsrc=duration=5.3:size=qcif:rate=10
10295 will generate a video with a duration of 5.3 seconds, with size
10296 176x144 and a frame rate of 10 frames per second.
10298 The following graph description will generate a red source
10299 with an opacity of 0.2, with size "qcif" and a frame rate of 10
10302 color=c=red@@0.2:s=qcif:r=10
10305 If the input content is to be ignored, @code{nullsrc} can be used. The
10306 following command generates noise in the luminance plane by employing
10307 the @code{geq} filter:
10309 nullsrc=s=256x256, geq=random(1)*255:128:128
10312 @subsection Commands
10314 The @code{color} source supports the following commands:
10318 Set the color of the created image. Accepts the same syntax of the
10319 corresponding @option{color} option.
10322 @c man end VIDEO SOURCES
10324 @chapter Video Sinks
10325 @c man begin VIDEO SINKS
10327 Below is a description of the currently available video sinks.
10329 @section buffersink
10331 Buffer video frames, and make them available to the end of the filter
10334 This sink is mainly intended for programmatic use, in particular
10335 through the interface defined in @file{libavfilter/buffersink.h}
10336 or the options system.
10338 It accepts a pointer to an AVBufferSinkContext structure, which
10339 defines the incoming buffers' formats, to be passed as the opaque
10340 parameter to @code{avfilter_init_filter} for initialization.
10344 Null video sink: do absolutely nothing with the input video. It is
10345 mainly useful as a template and for use in analysis / debugging
10348 @c man end VIDEO SINKS
10350 @chapter Multimedia Filters
10351 @c man begin MULTIMEDIA FILTERS
10353 Below is a description of the currently available multimedia filters.
10355 @section avectorscope
10357 Convert input audio to a video output, representing the audio vector
10360 The filter is used to measure the difference between channels of stereo
10361 audio stream. A monoaural signal, consisting of identical left and right
10362 signal, results in straight vertical line. Any stereo separation is visible
10363 as a deviation from this line, creating a Lissajous figure.
10364 If the straight (or deviation from it) but horizontal line appears this
10365 indicates that the left and right channels are out of phase.
10367 The filter accepts the following options:
10371 Set the vectorscope mode.
10373 Available values are:
10376 Lissajous rotated by 45 degrees.
10379 Same as above but not rotated.
10382 Default value is @samp{lissajous}.
10385 Set the video size for the output. For the syntax of this option, check the "Video size"
10386 section in the ffmpeg-utils manual. Default value is @code{400x400}.
10389 Set the output frame rate. Default value is @code{25}.
10394 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
10395 Allowed range is @code{[0, 255]}.
10400 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
10401 Allowed range is @code{[0, 255]}.
10404 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
10407 @subsection Examples
10411 Complete example using @command{ffplay}:
10413 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10414 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
10420 Concatenate audio and video streams, joining them together one after the
10423 The filter works on segments of synchronized video and audio streams. All
10424 segments must have the same number of streams of each type, and that will
10425 also be the number of streams at output.
10427 The filter accepts the following options:
10432 Set the number of segments. Default is 2.
10435 Set the number of output video streams, that is also the number of video
10436 streams in each segment. Default is 1.
10439 Set the number of output audio streams, that is also the number of audio
10440 streams in each segment. Default is 0.
10443 Activate unsafe mode: do not fail if segments have a different format.
10447 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
10448 @var{a} audio outputs.
10450 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
10451 segment, in the same order as the outputs, then the inputs for the second
10454 Related streams do not always have exactly the same duration, for various
10455 reasons including codec frame size or sloppy authoring. For that reason,
10456 related synchronized streams (e.g. a video and its audio track) should be
10457 concatenated at once. The concat filter will use the duration of the longest
10458 stream in each segment (except the last one), and if necessary pad shorter
10459 audio streams with silence.
10461 For this filter to work correctly, all segments must start at timestamp 0.
10463 All corresponding streams must have the same parameters in all segments; the
10464 filtering system will automatically select a common pixel format for video
10465 streams, and a common sample format, sample rate and channel layout for
10466 audio streams, but other settings, such as resolution, must be converted
10467 explicitly by the user.
10469 Different frame rates are acceptable but will result in variable frame rate
10470 at output; be sure to configure the output file to handle it.
10472 @subsection Examples
10476 Concatenate an opening, an episode and an ending, all in bilingual version
10477 (video in stream 0, audio in streams 1 and 2):
10479 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
10480 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
10481 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
10482 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
10486 Concatenate two parts, handling audio and video separately, using the
10487 (a)movie sources, and adjusting the resolution:
10489 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
10490 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
10491 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
10493 Note that a desync will happen at the stitch if the audio and video streams
10494 do not have exactly the same duration in the first file.
10500 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
10501 it unchanged. By default, it logs a message at a frequency of 10Hz with the
10502 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
10503 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
10505 The filter also has a video output (see the @var{video} option) with a real
10506 time graph to observe the loudness evolution. The graphic contains the logged
10507 message mentioned above, so it is not printed anymore when this option is set,
10508 unless the verbose logging is set. The main graphing area contains the
10509 short-term loudness (3 seconds of analysis), and the gauge on the right is for
10510 the momentary loudness (400 milliseconds).
10512 More information about the Loudness Recommendation EBU R128 on
10513 @url{http://tech.ebu.ch/loudness}.
10515 The filter accepts the following options:
10520 Activate the video output. The audio stream is passed unchanged whether this
10521 option is set or no. The video stream will be the first output stream if
10522 activated. Default is @code{0}.
10525 Set the video size. This option is for video only. For the syntax of this
10526 option, check the "Video size" section in the ffmpeg-utils manual. Default
10527 and minimum resolution is @code{640x480}.
10530 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
10531 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
10532 other integer value between this range is allowed.
10535 Set metadata injection. If set to @code{1}, the audio input will be segmented
10536 into 100ms output frames, each of them containing various loudness information
10537 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
10539 Default is @code{0}.
10542 Force the frame logging level.
10544 Available values are:
10547 information logging level
10549 verbose logging level
10552 By default, the logging level is set to @var{info}. If the @option{video} or
10553 the @option{metadata} options are set, it switches to @var{verbose}.
10558 Available modes can be cumulated (the option is a @code{flag} type). Possible
10562 Disable any peak mode (default).
10564 Enable sample-peak mode.
10566 Simple peak mode looking for the higher sample value. It logs a message
10567 for sample-peak (identified by @code{SPK}).
10569 Enable true-peak mode.
10571 If enabled, the peak lookup is done on an over-sampled version of the input
10572 stream for better peak accuracy. It logs a message for true-peak.
10573 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
10574 This mode requires a build with @code{libswresample}.
10579 @subsection Examples
10583 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
10585 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
10589 Run an analysis with @command{ffmpeg}:
10591 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
10595 @section interleave, ainterleave
10597 Temporally interleave frames from several inputs.
10599 @code{interleave} works with video inputs, @code{ainterleave} with audio.
10601 These filters read frames from several inputs and send the oldest
10602 queued frame to the output.
10604 Input streams must have a well defined, monotonically increasing frame
10607 In order to submit one frame to output, these filters need to enqueue
10608 at least one frame for each input, so they cannot work in case one
10609 input is not yet terminated and will not receive incoming frames.
10611 For example consider the case when one input is a @code{select} filter
10612 which always drop input frames. The @code{interleave} filter will keep
10613 reading from that input, but it will never be able to send new frames
10614 to output until the input will send an end-of-stream signal.
10616 Also, depending on inputs synchronization, the filters will drop
10617 frames in case one input receives more frames than the other ones, and
10618 the queue is already filled.
10620 These filters accept the following options:
10624 Set the number of different inputs, it is 2 by default.
10627 @subsection Examples
10631 Interleave frames belonging to different streams using @command{ffmpeg}:
10633 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
10637 Add flickering blur effect:
10639 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
10643 @section perms, aperms
10645 Set read/write permissions for the output frames.
10647 These filters are mainly aimed at developers to test direct path in the
10648 following filter in the filtergraph.
10650 The filters accept the following options:
10654 Select the permissions mode.
10656 It accepts the following values:
10659 Do nothing. This is the default.
10661 Set all the output frames read-only.
10663 Set all the output frames directly writable.
10665 Make the frame read-only if writable, and writable if read-only.
10667 Set each output frame read-only or writable randomly.
10671 Set the seed for the @var{random} mode, must be an integer included between
10672 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
10673 @code{-1}, the filter will try to use a good random seed on a best effort
10677 Note: in case of auto-inserted filter between the permission filter and the
10678 following one, the permission might not be received as expected in that
10679 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
10680 perms/aperms filter can avoid this problem.
10682 @section select, aselect
10684 Select frames to pass in output.
10686 This filter accepts the following options:
10691 Set expression, which is evaluated for each input frame.
10693 If the expression is evaluated to zero, the frame is discarded.
10695 If the evaluation result is negative or NaN, the frame is sent to the
10696 first output; otherwise it is sent to the output with index
10697 @code{ceil(val)-1}, assuming that the input index starts from 0.
10699 For example a value of @code{1.2} corresponds to the output with index
10700 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
10703 Set the number of outputs. The output to which to send the selected
10704 frame is based on the result of the evaluation. Default value is 1.
10707 The expression can contain the following constants:
10711 The (sequential) number of the filtered frame, starting from 0.
10714 The (sequential) number of the selected frame, starting from 0.
10716 @item prev_selected_n
10717 The sequential number of the last selected frame. It's NAN if undefined.
10720 The timebase of the input timestamps.
10723 The PTS (Presentation TimeStamp) of the filtered video frame,
10724 expressed in @var{TB} units. It's NAN if undefined.
10727 The PTS of the filtered video frame,
10728 expressed in seconds. It's NAN if undefined.
10731 The PTS of the previously filtered video frame. It's NAN if undefined.
10733 @item prev_selected_pts
10734 The PTS of the last previously filtered video frame. It's NAN if undefined.
10736 @item prev_selected_t
10737 The PTS of the last previously selected video frame. It's NAN if undefined.
10740 The PTS of the first video frame in the video. It's NAN if undefined.
10743 The time of the first video frame in the video. It's NAN if undefined.
10745 @item pict_type @emph{(video only)}
10746 The type of the filtered frame. It can assume one of the following
10758 @item interlace_type @emph{(video only)}
10759 The frame interlace type. It can assume one of the following values:
10762 The frame is progressive (not interlaced).
10764 The frame is top-field-first.
10766 The frame is bottom-field-first.
10769 @item consumed_sample_n @emph{(audio only)}
10770 the number of selected samples before the current frame
10772 @item samples_n @emph{(audio only)}
10773 the number of samples in the current frame
10775 @item sample_rate @emph{(audio only)}
10776 the input sample rate
10779 This is 1 if the filtered frame is a key-frame, 0 otherwise.
10782 the position in the file of the filtered frame, -1 if the information
10783 is not available (e.g. for synthetic video)
10785 @item scene @emph{(video only)}
10786 value between 0 and 1 to indicate a new scene; a low value reflects a low
10787 probability for the current frame to introduce a new scene, while a higher
10788 value means the current frame is more likely to be one (see the example below)
10792 The default value of the select expression is "1".
10794 @subsection Examples
10798 Select all frames in input:
10803 The example above is the same as:
10815 Select only I-frames:
10817 select='eq(pict_type\,I)'
10821 Select one frame every 100:
10823 select='not(mod(n\,100))'
10827 Select only frames contained in the 10-20 time interval:
10829 select=between(t\,10\,20)
10833 Select only I frames contained in the 10-20 time interval:
10835 select=between(t\,10\,20)*eq(pict_type\,I)
10839 Select frames with a minimum distance of 10 seconds:
10841 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
10845 Use aselect to select only audio frames with samples number > 100:
10847 aselect='gt(samples_n\,100)'
10851 Create a mosaic of the first scenes:
10853 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
10856 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
10860 Send even and odd frames to separate outputs, and compose them:
10862 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
10866 @section sendcmd, asendcmd
10868 Send commands to filters in the filtergraph.
10870 These filters read commands to be sent to other filters in the
10873 @code{sendcmd} must be inserted between two video filters,
10874 @code{asendcmd} must be inserted between two audio filters, but apart
10875 from that they act the same way.
10877 The specification of commands can be provided in the filter arguments
10878 with the @var{commands} option, or in a file specified by the
10879 @var{filename} option.
10881 These filters accept the following options:
10884 Set the commands to be read and sent to the other filters.
10886 Set the filename of the commands to be read and sent to the other
10890 @subsection Commands syntax
10892 A commands description consists of a sequence of interval
10893 specifications, comprising a list of commands to be executed when a
10894 particular event related to that interval occurs. The occurring event
10895 is typically the current frame time entering or leaving a given time
10898 An interval is specified by the following syntax:
10900 @var{START}[-@var{END}] @var{COMMANDS};
10903 The time interval is specified by the @var{START} and @var{END} times.
10904 @var{END} is optional and defaults to the maximum time.
10906 The current frame time is considered within the specified interval if
10907 it is included in the interval [@var{START}, @var{END}), that is when
10908 the time is greater or equal to @var{START} and is lesser than
10911 @var{COMMANDS} consists of a sequence of one or more command
10912 specifications, separated by ",", relating to that interval. The
10913 syntax of a command specification is given by:
10915 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
10918 @var{FLAGS} is optional and specifies the type of events relating to
10919 the time interval which enable sending the specified command, and must
10920 be a non-null sequence of identifier flags separated by "+" or "|" and
10921 enclosed between "[" and "]".
10923 The following flags are recognized:
10926 The command is sent when the current frame timestamp enters the
10927 specified interval. In other words, the command is sent when the
10928 previous frame timestamp was not in the given interval, and the
10932 The command is sent when the current frame timestamp leaves the
10933 specified interval. In other words, the command is sent when the
10934 previous frame timestamp was in the given interval, and the
10938 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
10941 @var{TARGET} specifies the target of the command, usually the name of
10942 the filter class or a specific filter instance name.
10944 @var{COMMAND} specifies the name of the command for the target filter.
10946 @var{ARG} is optional and specifies the optional list of argument for
10947 the given @var{COMMAND}.
10949 Between one interval specification and another, whitespaces, or
10950 sequences of characters starting with @code{#} until the end of line,
10951 are ignored and can be used to annotate comments.
10953 A simplified BNF description of the commands specification syntax
10956 @var{COMMAND_FLAG} ::= "enter" | "leave"
10957 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
10958 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
10959 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
10960 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
10961 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
10964 @subsection Examples
10968 Specify audio tempo change at second 4:
10970 asendcmd=c='4.0 atempo tempo 1.5',atempo
10974 Specify a list of drawtext and hue commands in a file.
10976 # show text in the interval 5-10
10977 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
10978 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
10980 # desaturate the image in the interval 15-20
10981 15.0-20.0 [enter] hue s 0,
10982 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
10984 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
10986 # apply an exponential saturation fade-out effect, starting from time 25
10987 25 [enter] hue s exp(25-t)
10990 A filtergraph allowing to read and process the above command list
10991 stored in a file @file{test.cmd}, can be specified with:
10993 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
10998 @section setpts, asetpts
11000 Change the PTS (presentation timestamp) of the input frames.
11002 @code{setpts} works on video frames, @code{asetpts} on audio frames.
11004 This filter accepts the following options:
11009 The expression which is evaluated for each frame to construct its timestamp.
11013 The expression is evaluated through the eval API and can contain the following
11018 frame rate, only defined for constant frame-rate video
11021 The presentation timestamp in input
11024 The count of the input frame for video or the number of consumed samples,
11025 not including the current frame for audio, starting from 0.
11027 @item NB_CONSUMED_SAMPLES
11028 The number of consumed samples, not including the current frame (only
11031 @item NB_SAMPLES, S
11032 The number of samples in the current frame (only audio)
11034 @item SAMPLE_RATE, SR
11035 The audio sample rate.
11038 The PTS of the first frame.
11041 the time in seconds of the first frame
11044 State whether the current frame is interlaced.
11047 the time in seconds of the current frame
11050 original position in the file of the frame, or undefined if undefined
11051 for the current frame
11054 The previous input PTS.
11057 previous input time in seconds
11060 The previous output PTS.
11063 previous output time in seconds
11066 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
11070 The wallclock (RTC) time at the start of the movie in microseconds.
11073 The timebase of the input timestamps.
11077 @subsection Examples
11081 Start counting PTS from zero
11083 setpts=PTS-STARTPTS
11087 Apply fast motion effect:
11093 Apply slow motion effect:
11099 Set fixed rate of 25 frames per second:
11105 Set fixed rate 25 fps with some jitter:
11107 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
11111 Apply an offset of 10 seconds to the input PTS:
11117 Generate timestamps from a "live source" and rebase onto the current timebase:
11119 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
11123 Generate timestamps by counting samples:
11130 @section settb, asettb
11132 Set the timebase to use for the output frames timestamps.
11133 It is mainly useful for testing timebase configuration.
11135 It accepts the following parameters:
11140 The expression which is evaluated into the output timebase.
11144 The value for @option{tb} is an arithmetic expression representing a
11145 rational. The expression can contain the constants "AVTB" (the default
11146 timebase), "intb" (the input timebase) and "sr" (the sample rate,
11147 audio only). Default value is "intb".
11149 @subsection Examples
11153 Set the timebase to 1/25:
11159 Set the timebase to 1/10:
11165 Set the timebase to 1001/1000:
11171 Set the timebase to 2*intb:
11177 Set the default timebase value:
11184 Convert input audio to a video output representing
11185 frequency spectrum logarithmically (using constant Q transform with
11186 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
11188 The filter accepts the following options:
11192 Specify transform volume (multiplier) expression. The expression can contain
11195 @item frequency, freq, f
11196 the frequency where transform is evaluated
11197 @item timeclamp, tc
11198 value of timeclamp option
11202 @item a_weighting(f)
11203 A-weighting of equal loudness
11204 @item b_weighting(f)
11205 B-weighting of equal loudness
11206 @item c_weighting(f)
11207 C-weighting of equal loudness
11209 Default value is @code{16}.
11212 Specify transform length expression. The expression can contain variables:
11214 @item frequency, freq, f
11215 the frequency where transform is evaluated
11216 @item timeclamp, tc
11217 value of timeclamp option
11219 Default value is @code{384/f*tc/(384/f+tc)}.
11222 Specify the transform timeclamp. At low frequency, there is trade-off between
11223 accuracy in time domain and frequency domain. If timeclamp is lower,
11224 event in time domain is represented more accurately (such as fast bass drum),
11225 otherwise event in frequency domain is represented more accurately
11226 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
11229 Specify the transform coeffclamp. If coeffclamp is lower, transform is
11230 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
11231 Default value is @code{1.0}.
11234 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
11235 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
11236 Default value is @code{3.0}.
11239 Specify gamma of bargraph. Acceptable value is [1.0, 7.0].
11240 Default value is @code{1.0}.
11243 Specify font file for use with freetype. If not specified, use embedded font.
11246 Specify font color expression. This is arithmetic expression that should return
11247 integer value 0xRRGGBB. The expression can contain variables:
11249 @item frequency, freq, f
11250 the frequency where transform is evaluated
11251 @item timeclamp, tc
11252 value of timeclamp option
11257 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
11258 @item r(x), g(x), b(x)
11259 red, green, and blue value of intensity x
11261 Default value is @code{st(0, (midi(f)-59.5)/12);
11262 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
11263 r(1-ld(1)) + b(ld(1))}
11266 If set to 1 (the default), the video size is 1920x1080 (full HD),
11267 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
11270 Specify video fps. Default value is @code{25}.
11273 Specify number of transform per frame, so there are fps*count transforms
11274 per second. Note that audio data rate must be divisible by fps*count.
11275 Default value is @code{6}.
11279 @subsection Examples
11283 Playing audio while showing the spectrum:
11285 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
11289 Same as above, but with frame rate 30 fps:
11291 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
11295 Playing at 960x540 and lower CPU usage:
11297 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
11301 A1 and its harmonics: A1, A2, (near)E3, A3:
11303 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),
11304 asplit[a][out1]; [a] showcqt [out0]'
11308 Same as above, but with more accuracy in frequency domain (and slower):
11310 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),
11311 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
11315 B-weighting of equal loudness
11317 volume=16*b_weighting(f)
11323 tlength=100/f*tc/(100/f+tc)
11327 Custom fontcolor, C-note is colored green, others are colored blue
11329 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))'
11333 Custom gamma, now spectrum is linear to the amplitude.
11340 @section showspectrum
11342 Convert input audio to a video output, representing the audio frequency
11345 The filter accepts the following options:
11349 Specify the video size for the output. For the syntax of this option, check
11350 the "Video size" section in the ffmpeg-utils manual. Default value is
11354 Specify how the spectrum should slide along the window.
11356 It accepts the following values:
11359 the samples start again on the left when they reach the right
11361 the samples scroll from right to left
11363 frames are only produced when the samples reach the right
11366 Default value is @code{replace}.
11369 Specify display mode.
11371 It accepts the following values:
11374 all channels are displayed in the same row
11376 all channels are displayed in separate rows
11379 Default value is @samp{combined}.
11382 Specify display color mode.
11384 It accepts the following values:
11387 each channel is displayed in a separate color
11389 each channel is is displayed using the same color scheme
11392 Default value is @samp{channel}.
11395 Specify scale used for calculating intensity color values.
11397 It accepts the following values:
11402 square root, default
11409 Default value is @samp{sqrt}.
11412 Set saturation modifier for displayed colors. Negative values provide
11413 alternative color scheme. @code{0} is no saturation at all.
11414 Saturation must be in [-10.0, 10.0] range.
11415 Default value is @code{1}.
11418 Set window function.
11420 It accepts the following values:
11423 No samples pre-processing (do not expect this to be faster)
11432 Default value is @code{hann}.
11435 The usage is very similar to the showwaves filter; see the examples in that
11438 @subsection Examples
11442 Large window with logarithmic color scaling:
11444 showspectrum=s=1280x480:scale=log
11448 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
11450 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
11451 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
11457 Convert input audio to a video output, representing the samples waves.
11459 The filter accepts the following options:
11463 Specify the video size for the output. For the syntax of this option, check
11464 the "Video size" section in the ffmpeg-utils manual. Default value
11470 Available values are:
11473 Draw a point for each sample.
11476 Draw a vertical line for each sample.
11479 Draw a point for each sample and a line between them.
11482 Draw a centered vertical line for each sample.
11485 Default value is @code{point}.
11488 Set the number of samples which are printed on the same column. A
11489 larger value will decrease the frame rate. Must be a positive
11490 integer. This option can be set only if the value for @var{rate}
11491 is not explicitly specified.
11494 Set the (approximate) output frame rate. This is done by setting the
11495 option @var{n}. Default value is "25".
11497 @item split_channels
11498 Set if channels should be drawn separately or overlap. Default value is 0.
11502 @subsection Examples
11506 Output the input file audio and the corresponding video representation
11509 amovie=a.mp3,asplit[out0],showwaves[out1]
11513 Create a synthetic signal and show it with showwaves, forcing a
11514 frame rate of 30 frames per second:
11516 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
11520 @section split, asplit
11522 Split input into several identical outputs.
11524 @code{asplit} works with audio input, @code{split} with video.
11526 The filter accepts a single parameter which specifies the number of outputs. If
11527 unspecified, it defaults to 2.
11529 @subsection Examples
11533 Create two separate outputs from the same input:
11535 [in] split [out0][out1]
11539 To create 3 or more outputs, you need to specify the number of
11542 [in] asplit=3 [out0][out1][out2]
11546 Create two separate outputs from the same input, one cropped and
11549 [in] split [splitout1][splitout2];
11550 [splitout1] crop=100:100:0:0 [cropout];
11551 [splitout2] pad=200:200:100:100 [padout];
11555 Create 5 copies of the input audio with @command{ffmpeg}:
11557 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
11563 Receive commands sent through a libzmq client, and forward them to
11564 filters in the filtergraph.
11566 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
11567 must be inserted between two video filters, @code{azmq} between two
11570 To enable these filters you need to install the libzmq library and
11571 headers and configure FFmpeg with @code{--enable-libzmq}.
11573 For more information about libzmq see:
11574 @url{http://www.zeromq.org/}
11576 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
11577 receives messages sent through a network interface defined by the
11578 @option{bind_address} option.
11580 The received message must be in the form:
11582 @var{TARGET} @var{COMMAND} [@var{ARG}]
11585 @var{TARGET} specifies the target of the command, usually the name of
11586 the filter class or a specific filter instance name.
11588 @var{COMMAND} specifies the name of the command for the target filter.
11590 @var{ARG} is optional and specifies the optional argument list for the
11591 given @var{COMMAND}.
11593 Upon reception, the message is processed and the corresponding command
11594 is injected into the filtergraph. Depending on the result, the filter
11595 will send a reply to the client, adopting the format:
11597 @var{ERROR_CODE} @var{ERROR_REASON}
11601 @var{MESSAGE} is optional.
11603 @subsection Examples
11605 Look at @file{tools/zmqsend} for an example of a zmq client which can
11606 be used to send commands processed by these filters.
11608 Consider the following filtergraph generated by @command{ffplay}
11610 ffplay -dumpgraph 1 -f lavfi "
11611 color=s=100x100:c=red [l];
11612 color=s=100x100:c=blue [r];
11613 nullsrc=s=200x100, zmq [bg];
11614 [bg][l] overlay [bg+l];
11615 [bg+l][r] overlay=x=100 "
11618 To change the color of the left side of the video, the following
11619 command can be used:
11621 echo Parsed_color_0 c yellow | tools/zmqsend
11624 To change the right side:
11626 echo Parsed_color_1 c pink | tools/zmqsend
11629 @c man end MULTIMEDIA FILTERS
11631 @chapter Multimedia Sources
11632 @c man begin MULTIMEDIA SOURCES
11634 Below is a description of the currently available multimedia sources.
11638 This is the same as @ref{movie} source, except it selects an audio
11644 Read audio and/or video stream(s) from a movie container.
11646 It accepts the following parameters:
11650 The name of the resource to read (not necessarily a file; it can also be a
11651 device or a stream accessed through some protocol).
11653 @item format_name, f
11654 Specifies the format assumed for the movie to read, and can be either
11655 the name of a container or an input device. If not specified, the
11656 format is guessed from @var{movie_name} or by probing.
11658 @item seek_point, sp
11659 Specifies the seek point in seconds. The frames will be output
11660 starting from this seek point. The parameter is evaluated with
11661 @code{av_strtod}, so the numerical value may be suffixed by an IS
11662 postfix. The default value is "0".
11665 Specifies the streams to read. Several streams can be specified,
11666 separated by "+". The source will then have as many outputs, in the
11667 same order. The syntax is explained in the ``Stream specifiers''
11668 section in the ffmpeg manual. Two special names, "dv" and "da" specify
11669 respectively the default (best suited) video and audio stream. Default
11670 is "dv", or "da" if the filter is called as "amovie".
11672 @item stream_index, si
11673 Specifies the index of the video stream to read. If the value is -1,
11674 the most suitable video stream will be automatically selected. The default
11675 value is "-1". Deprecated. If the filter is called "amovie", it will select
11676 audio instead of video.
11679 Specifies how many times to read the stream in sequence.
11680 If the value is less than 1, the stream will be read again and again.
11681 Default value is "1".
11683 Note that when the movie is looped the source timestamps are not
11684 changed, so it will generate non monotonically increasing timestamps.
11687 It allows overlaying a second video on top of the main input of
11688 a filtergraph, as shown in this graph:
11690 input -----------> deltapts0 --> overlay --> output
11693 movie --> scale--> deltapts1 -------+
11695 @subsection Examples
11699 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
11700 on top of the input labelled "in":
11702 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
11703 [in] setpts=PTS-STARTPTS [main];
11704 [main][over] overlay=16:16 [out]
11708 Read from a video4linux2 device, and overlay it on top of the input
11711 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
11712 [in] setpts=PTS-STARTPTS [main];
11713 [main][over] overlay=16:16 [out]
11717 Read the first video stream and the audio stream with id 0x81 from
11718 dvd.vob; the video is connected to the pad named "video" and the audio is
11719 connected to the pad named "audio":
11721 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
11725 @c man end MULTIMEDIA SOURCES