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
2639 Blend two video frames into each other.
2641 It takes two input streams and outputs one stream, the first input is the
2642 "top" layer and second input is "bottom" layer.
2643 Output terminates when shortest input terminates.
2645 A description of the accepted options follows.
2653 Set blend mode for specific pixel component or all pixel components in case
2654 of @var{all_mode}. Default value is @code{normal}.
2656 Available values for component modes are:
2689 Set blend opacity for specific pixel component or all pixel components in case
2690 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2697 Set blend expression for specific pixel component or all pixel components in case
2698 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2700 The expressions can use the following variables:
2704 The sequential number of the filtered frame, starting from @code{0}.
2708 the coordinates of the current sample
2712 the width and height of currently filtered plane
2716 Width and height scale depending on the currently filtered plane. It is the
2717 ratio between the corresponding luma plane number of pixels and the current
2718 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2719 @code{0.5,0.5} for chroma planes.
2722 Time of the current frame, expressed in seconds.
2725 Value of pixel component at current location for first video frame (top layer).
2728 Value of pixel component at current location for second video frame (bottom layer).
2732 Force termination when the shortest input terminates. Default is @code{0}.
2734 Continue applying the last bottom frame after the end of the stream. A value of
2735 @code{0} disable the filter after the last frame of the bottom layer is reached.
2736 Default is @code{1}.
2739 @subsection Examples
2743 Apply transition from bottom layer to top layer in first 10 seconds:
2745 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2749 Apply 1x1 checkerboard effect:
2751 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2755 Apply uncover left effect:
2757 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2761 Apply uncover down effect:
2763 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2767 Apply uncover up-left effect:
2769 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2775 Apply a boxblur algorithm to the input video.
2777 It accepts the following parameters:
2781 @item luma_radius, lr
2782 @item luma_power, lp
2783 @item chroma_radius, cr
2784 @item chroma_power, cp
2785 @item alpha_radius, ar
2786 @item alpha_power, ap
2790 A description of the accepted options follows.
2793 @item luma_radius, lr
2794 @item chroma_radius, cr
2795 @item alpha_radius, ar
2796 Set an expression for the box radius in pixels used for blurring the
2797 corresponding input plane.
2799 The radius value must be a non-negative number, and must not be
2800 greater than the value of the expression @code{min(w,h)/2} for the
2801 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2804 Default value for @option{luma_radius} is "2". If not specified,
2805 @option{chroma_radius} and @option{alpha_radius} default to the
2806 corresponding value set for @option{luma_radius}.
2808 The expressions can contain the following constants:
2812 The input width and height in pixels.
2816 The input chroma image width and height in pixels.
2820 The horizontal and vertical chroma subsample values. For example, for the
2821 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
2824 @item luma_power, lp
2825 @item chroma_power, cp
2826 @item alpha_power, ap
2827 Specify how many times the boxblur filter is applied to the
2828 corresponding plane.
2830 Default value for @option{luma_power} is 2. If not specified,
2831 @option{chroma_power} and @option{alpha_power} default to the
2832 corresponding value set for @option{luma_power}.
2834 A value of 0 will disable the effect.
2837 @subsection Examples
2841 Apply a boxblur filter with the luma, chroma, and alpha radii
2844 boxblur=luma_radius=2:luma_power=1
2849 Set the luma radius to 2, and alpha and chroma radius to 0:
2851 boxblur=2:1:cr=0:ar=0
2855 Set the luma and chroma radii to a fraction of the video dimension:
2857 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2863 Visualize information exported by some codecs.
2865 Some codecs can export information through frames using side-data or other
2866 means. For example, some MPEG based codecs export motion vectors through the
2867 @var{export_mvs} flag in the codec @option{flags2} option.
2869 The filter accepts the following option:
2873 Set motion vectors to visualize.
2875 Available flags for @var{mv} are:
2879 forward predicted MVs of P-frames
2881 forward predicted MVs of B-frames
2883 backward predicted MVs of B-frames
2887 @subsection Examples
2891 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
2893 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
2897 @section colorbalance
2898 Modify intensity of primary colors (red, green and blue) of input frames.
2900 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2901 regions for the red-cyan, green-magenta or blue-yellow balance.
2903 A positive adjustment value shifts the balance towards the primary color, a negative
2904 value towards the complementary color.
2906 The filter accepts the following options:
2912 Adjust red, green and blue shadows (darkest pixels).
2917 Adjust red, green and blue midtones (medium pixels).
2922 Adjust red, green and blue highlights (brightest pixels).
2924 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2927 @subsection Examples
2931 Add red color cast to shadows:
2937 @section colorlevels
2939 Adjust video input frames using levels.
2941 The filter accepts the following options:
2948 Adjust red, green, blue and alpha input black point.
2949 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2955 Adjust red, green, blue and alpha input white point.
2956 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
2958 Input levels are used to lighten highlights (bright tones), darken shadows
2959 (dark tones), change the balance of bright and dark tones.
2965 Adjust red, green, blue and alpha output black point.
2966 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
2972 Adjust red, green, blue and alpha output white point.
2973 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
2975 Output levels allows manual selection of a constrained output level range.
2978 @subsection Examples
2982 Make video output darker:
2984 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
2990 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
2994 Make video output lighter:
2996 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
3000 Increase brightness:
3002 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
3006 @section colorchannelmixer
3008 Adjust video input frames by re-mixing color channels.
3010 This filter modifies a color channel by adding the values associated to
3011 the other channels of the same pixels. For example if the value to
3012 modify is red, the output value will be:
3014 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
3017 The filter accepts the following options:
3024 Adjust contribution of input red, green, blue and alpha channels for output red channel.
3025 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
3031 Adjust contribution of input red, green, blue and alpha channels for output green channel.
3032 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
3038 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
3039 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
3045 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
3046 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
3048 Allowed ranges for options are @code{[-2.0, 2.0]}.
3051 @subsection Examples
3055 Convert source to grayscale:
3057 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
3060 Simulate sepia tones:
3062 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
3066 @section colormatrix
3068 Convert color matrix.
3070 The filter accepts the following options:
3075 Specify the source and destination color matrix. Both values must be
3078 The accepted values are:
3094 For example to convert from BT.601 to SMPTE-240M, use the command:
3096 colormatrix=bt601:smpte240m
3101 Copy the input source unchanged to the output. This is mainly useful for
3106 Crop the input video to given dimensions.
3108 It accepts the following parameters:
3112 The width of the output video. It defaults to @code{iw}.
3113 This expression is evaluated only once during the filter
3117 The height of the output video. It defaults to @code{ih}.
3118 This expression is evaluated only once during the filter
3122 The horizontal position, in the input video, of the left edge of the output
3123 video. It defaults to @code{(in_w-out_w)/2}.
3124 This expression is evaluated per-frame.
3127 The vertical position, in the input video, of the top edge of the output video.
3128 It defaults to @code{(in_h-out_h)/2}.
3129 This expression is evaluated per-frame.
3132 If set to 1 will force the output display aspect ratio
3133 to be the same of the input, by changing the output sample aspect
3134 ratio. It defaults to 0.
3137 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
3138 expressions containing the following constants:
3143 The computed values for @var{x} and @var{y}. They are evaluated for
3148 The input width and height.
3152 These are the same as @var{in_w} and @var{in_h}.
3156 The output (cropped) width and height.
3160 These are the same as @var{out_w} and @var{out_h}.
3163 same as @var{iw} / @var{ih}
3166 input sample aspect ratio
3169 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
3173 horizontal and vertical chroma subsample values. For example for the
3174 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3177 The number of the input frame, starting from 0.
3180 the position in the file of the input frame, NAN if unknown
3183 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
3187 The expression for @var{out_w} may depend on the value of @var{out_h},
3188 and the expression for @var{out_h} may depend on @var{out_w}, but they
3189 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
3190 evaluated after @var{out_w} and @var{out_h}.
3192 The @var{x} and @var{y} parameters specify the expressions for the
3193 position of the top-left corner of the output (non-cropped) area. They
3194 are evaluated for each frame. If the evaluated value is not valid, it
3195 is approximated to the nearest valid value.
3197 The expression for @var{x} may depend on @var{y}, and the expression
3198 for @var{y} may depend on @var{x}.
3200 @subsection Examples
3204 Crop area with size 100x100 at position (12,34).
3209 Using named options, the example above becomes:
3211 crop=w=100:h=100:x=12:y=34
3215 Crop the central input area with size 100x100:
3221 Crop the central input area with size 2/3 of the input video:
3223 crop=2/3*in_w:2/3*in_h
3227 Crop the input video central square:
3234 Delimit the rectangle with the top-left corner placed at position
3235 100:100 and the right-bottom corner corresponding to the right-bottom
3236 corner of the input image.
3238 crop=in_w-100:in_h-100:100:100
3242 Crop 10 pixels from the left and right borders, and 20 pixels from
3243 the top and bottom borders
3245 crop=in_w-2*10:in_h-2*20
3249 Keep only the bottom right quarter of the input image:
3251 crop=in_w/2:in_h/2:in_w/2:in_h/2
3255 Crop height for getting Greek harmony:
3257 crop=in_w:1/PHI*in_w
3261 Apply trembling effect:
3263 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)
3267 Apply erratic camera effect depending on timestamp:
3269 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)"
3273 Set x depending on the value of y:
3275 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3281 Auto-detect the crop size.
3283 It calculates the necessary cropping parameters and prints the
3284 recommended parameters via the logging system. The detected dimensions
3285 correspond to the non-black area of the input video.
3287 It accepts the following parameters:
3292 Set higher black value threshold, which can be optionally specified
3293 from nothing (0) to everything (255). An intensity value greater
3294 to the set value is considered non-black. It defaults to 24.
3297 The value which the width/height should be divisible by. It defaults to
3298 16. The offset is automatically adjusted to center the video. Use 2 to
3299 get only even dimensions (needed for 4:2:2 video). 16 is best when
3300 encoding to most video codecs.
3302 @item reset_count, reset
3303 Set the counter that determines after how many frames cropdetect will
3304 reset the previously detected largest video area and start over to
3305 detect the current optimal crop area. Default value is 0.
3307 This can be useful when channel logos distort the video area. 0
3308 indicates 'never reset', and returns the largest area encountered during
3315 Apply color adjustments using curves.
3317 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3318 component (red, green and blue) has its values defined by @var{N} key points
3319 tied from each other using a smooth curve. The x-axis represents the pixel
3320 values from the input frame, and the y-axis the new pixel values to be set for
3323 By default, a component curve is defined by the two points @var{(0;0)} and
3324 @var{(1;1)}. This creates a straight line where each original pixel value is
3325 "adjusted" to its own value, which means no change to the image.
3327 The filter allows you to redefine these two points and add some more. A new
3328 curve (using a natural cubic spline interpolation) will be define to pass
3329 smoothly through all these new coordinates. The new defined points needs to be
3330 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3331 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3332 the vector spaces, the values will be clipped accordingly.
3334 If there is no key point defined in @code{x=0}, the filter will automatically
3335 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3336 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3338 The filter accepts the following options:
3342 Select one of the available color presets. This option can be used in addition
3343 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3344 options takes priority on the preset values.
3345 Available presets are:
3348 @item color_negative
3351 @item increase_contrast
3353 @item linear_contrast
3354 @item medium_contrast
3356 @item strong_contrast
3359 Default is @code{none}.
3361 Set the master key points. These points will define a second pass mapping. It
3362 is sometimes called a "luminance" or "value" mapping. It can be used with
3363 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3364 post-processing LUT.
3366 Set the key points for the red component.
3368 Set the key points for the green component.
3370 Set the key points for the blue component.
3372 Set the key points for all components (not including master).
3373 Can be used in addition to the other key points component
3374 options. In this case, the unset component(s) will fallback on this
3375 @option{all} setting.
3377 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3380 To avoid some filtergraph syntax conflicts, each key points list need to be
3381 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3383 @subsection Examples
3387 Increase slightly the middle level of blue:
3389 curves=blue='0.5/0.58'
3395 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3397 Here we obtain the following coordinates for each components:
3400 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3402 @code{(0;0) (0.50;0.48) (1;1)}
3404 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3408 The previous example can also be achieved with the associated built-in preset:
3410 curves=preset=vintage
3420 Use a Photoshop preset and redefine the points of the green component:
3422 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3428 Denoise frames using 2D DCT (frequency domain filtering).
3430 This filter is not designed for real time.
3432 The filter accepts the following options:
3436 Set the noise sigma constant.
3438 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3439 coefficient (absolute value) below this threshold with be dropped.
3441 If you need a more advanced filtering, see @option{expr}.
3443 Default is @code{0}.
3446 Set number overlapping pixels for each block. Since the filter can be slow, you
3447 may want to reduce this value, at the cost of a less effective filter and the
3448 risk of various artefacts.
3450 If the overlapping value doesn't allow to process the whole input width or
3451 height, a warning will be displayed and according borders won't be denoised.
3453 Default value is @var{blocksize}-1, which is the best possible setting.
3456 Set the coefficient factor expression.
3458 For each coefficient of a DCT block, this expression will be evaluated as a
3459 multiplier value for the coefficient.
3461 If this is option is set, the @option{sigma} option will be ignored.
3463 The absolute value of the coefficient can be accessed through the @var{c}
3467 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
3468 @var{blocksize}, which is the width and height of the processed blocks.
3470 The default value is @var{3} (8x8) and can be raised to @var{4} for a
3471 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
3472 on the speed processing. Also, a larger block size does not necessarily means a
3476 @subsection Examples
3478 Apply a denoise with a @option{sigma} of @code{4.5}:
3483 The same operation can be achieved using the expression system:
3485 dctdnoiz=e='gte(c, 4.5*3)'
3488 Violent denoise using a block size of @code{16x16}:
3496 Drop duplicated frames at regular intervals.
3498 The filter accepts the following options:
3502 Set the number of frames from which one will be dropped. Setting this to
3503 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3504 Default is @code{5}.
3507 Set the threshold for duplicate detection. If the difference metric for a frame
3508 is less than or equal to this value, then it is declared as duplicate. Default
3512 Set scene change threshold. Default is @code{15}.
3516 Set the size of the x and y-axis blocks used during metric calculations.
3517 Larger blocks give better noise suppression, but also give worse detection of
3518 small movements. Must be a power of two. Default is @code{32}.
3521 Mark main input as a pre-processed input and activate clean source input
3522 stream. This allows the input to be pre-processed with various filters to help
3523 the metrics calculation while keeping the frame selection lossless. When set to
3524 @code{1}, the first stream is for the pre-processed input, and the second
3525 stream is the clean source from where the kept frames are chosen. Default is
3529 Set whether or not chroma is considered in the metric calculations. Default is
3535 Remove judder produced by partially interlaced telecined content.
3537 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3538 source was partially telecined content then the output of @code{pullup,dejudder}
3539 will have a variable frame rate. May change the recorded frame rate of the
3540 container. Aside from that change, this filter will not affect constant frame
3543 The option available in this filter is:
3547 Specify the length of the window over which the judder repeats.
3549 Accepts any integer greater than 1. Useful values are:
3553 If the original was telecined from 24 to 30 fps (Film to NTSC).
3556 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3559 If a mixture of the two.
3562 The default is @samp{4}.
3567 Suppress a TV station logo by a simple interpolation of the surrounding
3568 pixels. Just set a rectangle covering the logo and watch it disappear
3569 (and sometimes something even uglier appear - your mileage may vary).
3571 It accepts the following parameters:
3576 Specify the top left corner coordinates of the logo. They must be
3581 Specify the width and height of the logo to clear. They must be
3585 Specify the thickness of the fuzzy edge of the rectangle (added to
3586 @var{w} and @var{h}). The default value is 4.
3589 When set to 1, a green rectangle is drawn on the screen to simplify
3590 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3591 The default value is 0.
3593 The rectangle is drawn on the outermost pixels which will be (partly)
3594 replaced with interpolated values. The values of the next pixels
3595 immediately outside this rectangle in each direction will be used to
3596 compute the interpolated pixel values inside the rectangle.
3600 @subsection Examples
3604 Set a rectangle covering the area with top left corner coordinates 0,0
3605 and size 100x77, and a band of size 10:
3607 delogo=x=0:y=0:w=100:h=77:band=10
3614 Attempt to fix small changes in horizontal and/or vertical shift. This
3615 filter helps remove camera shake from hand-holding a camera, bumping a
3616 tripod, moving on a vehicle, etc.
3618 The filter accepts the following options:
3626 Specify a rectangular area where to limit the search for motion
3628 If desired the search for motion vectors can be limited to a
3629 rectangular area of the frame defined by its top left corner, width
3630 and height. These parameters have the same meaning as the drawbox
3631 filter which can be used to visualise the position of the bounding
3634 This is useful when simultaneous movement of subjects within the frame
3635 might be confused for camera motion by the motion vector search.
3637 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3638 then the full frame is used. This allows later options to be set
3639 without specifying the bounding box for the motion vector search.
3641 Default - search the whole frame.
3645 Specify the maximum extent of movement in x and y directions in the
3646 range 0-64 pixels. Default 16.
3649 Specify how to generate pixels to fill blanks at the edge of the
3650 frame. Available values are:
3653 Fill zeroes at blank locations
3655 Original image at blank locations
3657 Extruded edge value at blank locations
3659 Mirrored edge at blank locations
3661 Default value is @samp{mirror}.
3664 Specify the blocksize to use for motion search. Range 4-128 pixels,
3668 Specify the contrast threshold for blocks. Only blocks with more than
3669 the specified contrast (difference between darkest and lightest
3670 pixels) will be considered. Range 1-255, default 125.
3673 Specify the search strategy. Available values are:
3676 Set exhaustive search
3678 Set less exhaustive search.
3680 Default value is @samp{exhaustive}.
3683 If set then a detailed log of the motion search is written to the
3687 If set to 1, specify using OpenCL capabilities, only available if
3688 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3694 Draw a colored box on the input image.
3696 It accepts the following parameters:
3701 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3705 The expressions which specify the width and height of the box; if 0 they are interpreted as
3706 the input width and height. It defaults to 0.
3709 Specify the color of the box to write. For the general syntax of this option,
3710 check the "Color" section in the ffmpeg-utils manual. If the special
3711 value @code{invert} is used, the box edge color is the same as the
3712 video with inverted luma.
3715 The expression which sets the thickness of the box edge. Default value is @code{3}.
3717 See below for the list of accepted constants.
3720 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3721 following constants:
3725 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3729 horizontal and vertical chroma subsample values. For example for the
3730 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3734 The input width and height.
3737 The input sample aspect ratio.
3741 The x and y offset coordinates where the box is drawn.
3745 The width and height of the drawn box.
3748 The thickness of the drawn box.
3750 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3751 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3755 @subsection Examples
3759 Draw a black box around the edge of the input image:
3765 Draw a box with color red and an opacity of 50%:
3767 drawbox=10:20:200:60:red@@0.5
3770 The previous example can be specified as:
3772 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3776 Fill the box with pink color:
3778 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3782 Draw a 2-pixel red 2.40:1 mask:
3784 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
3790 Draw a grid on the input image.
3792 It accepts the following parameters:
3797 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3801 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3802 input width and height, respectively, minus @code{thickness}, so image gets
3803 framed. Default to 0.
3806 Specify the color of the grid. For the general syntax of this option,
3807 check the "Color" section in the ffmpeg-utils manual. If the special
3808 value @code{invert} is used, the grid color is the same as the
3809 video with inverted luma.
3812 The expression which sets the thickness of the grid line. Default value is @code{1}.
3814 See below for the list of accepted constants.
3817 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3818 following constants:
3822 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3826 horizontal and vertical chroma subsample values. For example for the
3827 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3831 The input grid cell width and height.
3834 The input sample aspect ratio.
3838 The x and y coordinates of some point of grid intersection (meant to configure offset).
3842 The width and height of the drawn cell.
3845 The thickness of the drawn cell.
3847 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3848 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3852 @subsection Examples
3856 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3858 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3862 Draw a white 3x3 grid with an opacity of 50%:
3864 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3871 Draw a text string or text from a specified file on top of a video, using the
3872 libfreetype library.
3874 To enable compilation of this filter, you need to configure FFmpeg with
3875 @code{--enable-libfreetype}.
3876 To enable default font fallback and the @var{font} option you need to
3877 configure FFmpeg with @code{--enable-libfontconfig}.
3878 To enable the @var{text_shaping} option, you need to configure FFmpeg with
3879 @code{--enable-libfribidi}.
3883 It accepts the following parameters:
3888 Used to draw a box around text using the background color.
3889 The value must be either 1 (enable) or 0 (disable).
3890 The default value of @var{box} is 0.
3893 The color to be used for drawing box around text. For the syntax of this
3894 option, check the "Color" section in the ffmpeg-utils manual.
3896 The default value of @var{boxcolor} is "white".
3899 Set the width of the border to be drawn around the text using @var{bordercolor}.
3900 The default value of @var{borderw} is 0.
3903 Set the color to be used for drawing border around text. For the syntax of this
3904 option, check the "Color" section in the ffmpeg-utils manual.
3906 The default value of @var{bordercolor} is "black".
3909 Select how the @var{text} is expanded. Can be either @code{none},
3910 @code{strftime} (deprecated) or
3911 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3915 If true, check and fix text coords to avoid clipping.
3918 The color to be used for drawing fonts. For the syntax of this option, check
3919 the "Color" section in the ffmpeg-utils manual.
3921 The default value of @var{fontcolor} is "black".
3923 @item fontcolor_expr
3924 String which is expanded the same way as @var{text} to obtain dynamic
3925 @var{fontcolor} value. By default this option has empty value and is not
3926 processed. When this option is set, it overrides @var{fontcolor} option.
3929 The font family to be used for drawing text. By default Sans.
3932 The font file to be used for drawing text. The path must be included.
3933 This parameter is mandatory if the fontconfig support is disabled.
3936 The font size to be used for drawing text.
3937 The default value of @var{fontsize} is 16.
3940 If set to 1, attempt to shape the text (for example, reverse the order of
3941 right-to-left text and join Arabic characters) before drawing it.
3942 Otherwise, just draw the text exactly as given.
3943 By default 1 (if supported).
3946 The flags to be used for loading the fonts.
3948 The flags map the corresponding flags supported by libfreetype, and are
3949 a combination of the following values:
3956 @item vertical_layout
3957 @item force_autohint
3960 @item ignore_global_advance_width
3962 @item ignore_transform
3968 Default value is "default".
3970 For more information consult the documentation for the FT_LOAD_*
3974 The color to be used for drawing a shadow behind the drawn text. For the
3975 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3977 The default value of @var{shadowcolor} is "black".
3981 The x and y offsets for the text shadow position with respect to the
3982 position of the text. They can be either positive or negative
3983 values. The default value for both is "0".
3986 The starting frame number for the n/frame_num variable. The default value
3990 The size in number of spaces to use for rendering the tab.
3994 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3995 format. It can be used with or without text parameter. @var{timecode_rate}
3996 option must be specified.
3998 @item timecode_rate, rate, r
3999 Set the timecode frame rate (timecode only).
4002 The text string to be drawn. The text must be a sequence of UTF-8
4004 This parameter is mandatory if no file is specified with the parameter
4008 A text file containing text to be drawn. The text must be a sequence
4009 of UTF-8 encoded characters.
4011 This parameter is mandatory if no text string is specified with the
4012 parameter @var{text}.
4014 If both @var{text} and @var{textfile} are specified, an error is thrown.
4017 If set to 1, the @var{textfile} will be reloaded before each frame.
4018 Be sure to update it atomically, or it may be read partially, or even fail.
4022 The expressions which specify the offsets where text will be drawn
4023 within the video frame. They are relative to the top/left border of the
4026 The default value of @var{x} and @var{y} is "0".
4028 See below for the list of accepted constants and functions.
4031 The parameters for @var{x} and @var{y} are expressions containing the
4032 following constants and functions:
4036 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
4040 horizontal and vertical chroma subsample values. For example for the
4041 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4044 the height of each text line
4052 @item max_glyph_a, ascent
4053 the maximum distance from the baseline to the highest/upper grid
4054 coordinate used to place a glyph outline point, for all the rendered
4056 It is a positive value, due to the grid's orientation with the Y axis
4059 @item max_glyph_d, descent
4060 the maximum distance from the baseline to the lowest grid coordinate
4061 used to place a glyph outline point, for all the rendered glyphs.
4062 This is a negative value, due to the grid's orientation, with the Y axis
4066 maximum glyph height, that is the maximum height for all the glyphs
4067 contained in the rendered text, it is equivalent to @var{ascent} -
4071 maximum glyph width, that is the maximum width for all the glyphs
4072 contained in the rendered text
4075 the number of input frame, starting from 0
4077 @item rand(min, max)
4078 return a random number included between @var{min} and @var{max}
4081 The input sample aspect ratio.
4084 timestamp expressed in seconds, NAN if the input timestamp is unknown
4087 the height of the rendered text
4090 the width of the rendered text
4094 the x and y offset coordinates where the text is drawn.
4096 These parameters allow the @var{x} and @var{y} expressions to refer
4097 each other, so you can for example specify @code{y=x/dar}.
4100 @anchor{drawtext_expansion}
4101 @subsection Text expansion
4103 If @option{expansion} is set to @code{strftime},
4104 the filter recognizes strftime() sequences in the provided text and
4105 expands them accordingly. Check the documentation of strftime(). This
4106 feature is deprecated.
4108 If @option{expansion} is set to @code{none}, the text is printed verbatim.
4110 If @option{expansion} is set to @code{normal} (which is the default),
4111 the following expansion mechanism is used.
4113 The backslash character '\', followed by any character, always expands to
4114 the second character.
4116 Sequence of the form @code{%@{...@}} are expanded. The text between the
4117 braces is a function name, possibly followed by arguments separated by ':'.
4118 If the arguments contain special characters or delimiters (':' or '@}'),
4119 they should be escaped.
4121 Note that they probably must also be escaped as the value for the
4122 @option{text} option in the filter argument string and as the filter
4123 argument in the filtergraph description, and possibly also for the shell,
4124 that makes up to four levels of escaping; using a text file avoids these
4127 The following functions are available:
4132 The expression evaluation result.
4134 It must take one argument specifying the expression to be evaluated,
4135 which accepts the same constants and functions as the @var{x} and
4136 @var{y} values. Note that not all constants should be used, for
4137 example the text size is not known when evaluating the expression, so
4138 the constants @var{text_w} and @var{text_h} will have an undefined
4141 @item expr_int_format, eif
4142 Evaluate the expression's value and output as formatted integer.
4144 The first argument is the expression to be evaluated, just as for the @var{expr} function.
4145 The second argument specifies the output format. Allowed values are 'x', 'X', 'd' and
4146 'u'. They are treated exactly as in the printf function.
4147 The third parameter is optional and sets the number of positions taken by the output.
4148 It can be used to add padding with zeros from the left.
4151 The time at which the filter is running, expressed in UTC.
4152 It can accept an argument: a strftime() format string.
4155 The time at which the filter is running, expressed in the local time zone.
4156 It can accept an argument: a strftime() format string.
4159 Frame metadata. It must take one argument specifying metadata key.
4162 The frame number, starting from 0.
4165 A 1 character description of the current picture type.
4168 The timestamp of the current frame.
4169 It can take up to two arguments.
4171 The first argument is the format of the timestamp; it defaults to @code{flt}
4172 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
4173 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
4175 The second argument is an offset added to the timestamp.
4179 @subsection Examples
4183 Draw "Test Text" with font FreeSerif, using the default values for the
4184 optional parameters.
4187 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
4191 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
4192 and y=50 (counting from the top-left corner of the screen), text is
4193 yellow with a red box around it. Both the text and the box have an
4197 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
4198 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
4201 Note that the double quotes are not necessary if spaces are not used
4202 within the parameter list.
4205 Show the text at the center of the video frame:
4207 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
4211 Show a text line sliding from right to left in the last row of the video
4212 frame. The file @file{LONG_LINE} is assumed to contain a single line
4215 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
4219 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
4221 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
4225 Draw a single green letter "g", at the center of the input video.
4226 The glyph baseline is placed at half screen height.
4228 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
4232 Show text for 1 second every 3 seconds:
4234 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
4238 Use fontconfig to set the font. Note that the colons need to be escaped.
4240 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
4244 Print the date of a real-time encoding (see strftime(3)):
4246 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
4250 Show text fading in and out (appearing/disappearing):
4253 DS=1.0 # display start
4254 DE=10.0 # display end
4255 FID=1.5 # fade in duration
4256 FOD=5 # fade out duration
4257 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 @}"
4262 For more information about libfreetype, check:
4263 @url{http://www.freetype.org/}.
4265 For more information about fontconfig, check:
4266 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
4268 For more information about libfribidi, check:
4269 @url{http://fribidi.org/}.
4273 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
4275 The filter accepts the following options:
4280 Set low and high threshold values used by the Canny thresholding
4283 The high threshold selects the "strong" edge pixels, which are then
4284 connected through 8-connectivity with the "weak" edge pixels selected
4285 by the low threshold.
4287 @var{low} and @var{high} threshold values must be chosen in the range
4288 [0,1], and @var{low} should be lesser or equal to @var{high}.
4290 Default value for @var{low} is @code{20/255}, and default value for @var{high}
4294 Define the drawing mode.
4298 Draw white/gray wires on black background.
4301 Mix the colors to create a paint/cartoon effect.
4304 Default value is @var{wires}.
4307 @subsection Examples
4311 Standard edge detection with custom values for the hysteresis thresholding:
4313 edgedetect=low=0.1:high=0.4
4317 Painting effect without thresholding:
4319 edgedetect=mode=colormix:high=0
4323 @section extractplanes
4325 Extract color channel components from input video stream into
4326 separate grayscale video streams.
4328 The filter accepts the following option:
4332 Set plane(s) to extract.
4334 Available values for planes are:
4345 Choosing planes not available in the input will result in an error.
4346 That means you cannot select @code{r}, @code{g}, @code{b} planes
4347 with @code{y}, @code{u}, @code{v} planes at same time.
4350 @subsection Examples
4354 Extract luma, u and v color channel component from input video frame
4355 into 3 grayscale outputs:
4357 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
4363 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4365 For each input image, the filter will compute the optimal mapping from
4366 the input to the output given the codebook length, that is the number
4367 of distinct output colors.
4369 This filter accepts the following options.
4372 @item codebook_length, l
4373 Set codebook length. The value must be a positive integer, and
4374 represents the number of distinct output colors. Default value is 256.
4377 Set the maximum number of iterations to apply for computing the optimal
4378 mapping. The higher the value the better the result and the higher the
4379 computation time. Default value is 1.
4382 Set a random seed, must be an integer included between 0 and
4383 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4384 will try to use a good random seed on a best effort basis.
4389 Apply a fade-in/out effect to the input video.
4391 It accepts the following parameters:
4395 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4397 Default is @code{in}.
4399 @item start_frame, s
4400 Specify the number of the frame to start applying the fade
4401 effect at. Default is 0.
4404 The number of frames that the fade effect lasts. At the end of the
4405 fade-in effect, the output video will have the same intensity as the input video.
4406 At the end of the fade-out transition, the output video will be filled with the
4407 selected @option{color}.
4411 If set to 1, fade only alpha channel, if one exists on the input.
4414 @item start_time, st
4415 Specify the timestamp (in seconds) of the frame to start to apply the fade
4416 effect. If both start_frame and start_time are specified, the fade will start at
4417 whichever comes last. Default is 0.
4420 The number of seconds for which the fade effect has to last. At the end of the
4421 fade-in effect the output video will have the same intensity as the input video,
4422 at the end of the fade-out transition the output video will be filled with the
4423 selected @option{color}.
4424 If both duration and nb_frames are specified, duration is used. Default is 0.
4427 Specify the color of the fade. Default is "black".
4430 @subsection Examples
4434 Fade in the first 30 frames of video:
4439 The command above is equivalent to:
4445 Fade out the last 45 frames of a 200-frame video:
4448 fade=type=out:start_frame=155:nb_frames=45
4452 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4454 fade=in:0:25, fade=out:975:25
4458 Make the first 5 frames yellow, then fade in from frame 5-24:
4460 fade=in:5:20:color=yellow
4464 Fade in alpha over first 25 frames of video:
4466 fade=in:0:25:alpha=1
4470 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4472 fade=t=in:st=5.5:d=0.5
4479 Extract a single field from an interlaced image using stride
4480 arithmetic to avoid wasting CPU time. The output frames are marked as
4483 The filter accepts the following options:
4487 Specify whether to extract the top (if the value is @code{0} or
4488 @code{top}) or the bottom field (if the value is @code{1} or
4494 Field matching filter for inverse telecine. It is meant to reconstruct the
4495 progressive frames from a telecined stream. The filter does not drop duplicated
4496 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4497 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4499 The separation of the field matching and the decimation is notably motivated by
4500 the possibility of inserting a de-interlacing filter fallback between the two.
4501 If the source has mixed telecined and real interlaced content,
4502 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4503 But these remaining combed frames will be marked as interlaced, and thus can be
4504 de-interlaced by a later filter such as @ref{yadif} before decimation.
4506 In addition to the various configuration options, @code{fieldmatch} can take an
4507 optional second stream, activated through the @option{ppsrc} option. If
4508 enabled, the frames reconstruction will be based on the fields and frames from
4509 this second stream. This allows the first input to be pre-processed in order to
4510 help the various algorithms of the filter, while keeping the output lossless
4511 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4512 or brightness/contrast adjustments can help.
4514 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4515 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4516 which @code{fieldmatch} is based on. While the semantic and usage are very
4517 close, some behaviour and options names can differ.
4519 The @ref{decimate} filter currently only works for constant frame rate input.
4520 Do not use @code{fieldmatch} and @ref{decimate} if your input has mixed
4521 telecined and progressive content with changing framerate.
4523 The filter accepts the following options:
4527 Specify the assumed field order of the input stream. Available values are:
4531 Auto detect parity (use FFmpeg's internal parity value).
4533 Assume bottom field first.
4535 Assume top field first.
4538 Note that it is sometimes recommended not to trust the parity announced by the
4541 Default value is @var{auto}.
4544 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4545 sense that it won't risk creating jerkiness due to duplicate frames when
4546 possible, but if there are bad edits or blended fields it will end up
4547 outputting combed frames when a good match might actually exist. On the other
4548 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4549 but will almost always find a good frame if there is one. The other values are
4550 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4551 jerkiness and creating duplicate frames versus finding good matches in sections
4552 with bad edits, orphaned fields, blended fields, etc.
4554 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4556 Available values are:
4560 2-way matching (p/c)
4562 2-way matching, and trying 3rd match if still combed (p/c + n)
4564 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4566 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4567 still combed (p/c + n + u/b)
4569 3-way matching (p/c/n)
4571 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4572 detected as combed (p/c/n + u/b)
4575 The parenthesis at the end indicate the matches that would be used for that
4576 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4579 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4582 Default value is @var{pc_n}.
4585 Mark the main input stream as a pre-processed input, and enable the secondary
4586 input stream as the clean source to pick the fields from. See the filter
4587 introduction for more details. It is similar to the @option{clip2} feature from
4590 Default value is @code{0} (disabled).
4593 Set the field to match from. It is recommended to set this to the same value as
4594 @option{order} unless you experience matching failures with that setting. In
4595 certain circumstances changing the field that is used to match from can have a
4596 large impact on matching performance. Available values are:
4600 Automatic (same value as @option{order}).
4602 Match from the bottom field.
4604 Match from the top field.
4607 Default value is @var{auto}.
4610 Set whether or not chroma is included during the match comparisons. In most
4611 cases it is recommended to leave this enabled. You should set this to @code{0}
4612 only if your clip has bad chroma problems such as heavy rainbowing or other
4613 artifacts. Setting this to @code{0} could also be used to speed things up at
4614 the cost of some accuracy.
4616 Default value is @code{1}.
4620 These define an exclusion band which excludes the lines between @option{y0} and
4621 @option{y1} from being included in the field matching decision. An exclusion
4622 band can be used to ignore subtitles, a logo, or other things that may
4623 interfere with the matching. @option{y0} sets the starting scan line and
4624 @option{y1} sets the ending line; all lines in between @option{y0} and
4625 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4626 @option{y0} and @option{y1} to the same value will disable the feature.
4627 @option{y0} and @option{y1} defaults to @code{0}.
4630 Set the scene change detection threshold as a percentage of maximum change on
4631 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4632 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4633 @option{scthresh} is @code{[0.0, 100.0]}.
4635 Default value is @code{12.0}.
4638 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4639 account the combed scores of matches when deciding what match to use as the
4640 final match. Available values are:
4644 No final matching based on combed scores.
4646 Combed scores are only used when a scene change is detected.
4648 Use combed scores all the time.
4651 Default is @var{sc}.
4654 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4655 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4656 Available values are:
4660 No forced calculation.
4662 Force p/c/n calculations.
4664 Force p/c/n/u/b calculations.
4667 Default value is @var{none}.
4670 This is the area combing threshold used for combed frame detection. This
4671 essentially controls how "strong" or "visible" combing must be to be detected.
4672 Larger values mean combing must be more visible and smaller values mean combing
4673 can be less visible or strong and still be detected. Valid settings are from
4674 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4675 be detected as combed). This is basically a pixel difference value. A good
4676 range is @code{[8, 12]}.
4678 Default value is @code{9}.
4681 Sets whether or not chroma is considered in the combed frame decision. Only
4682 disable this if your source has chroma problems (rainbowing, etc.) that are
4683 causing problems for the combed frame detection with chroma enabled. Actually,
4684 using @option{chroma}=@var{0} is usually more reliable, except for the case
4685 where there is chroma only combing in the source.
4687 Default value is @code{0}.
4691 Respectively set the x-axis and y-axis size of the window used during combed
4692 frame detection. This has to do with the size of the area in which
4693 @option{combpel} pixels are required to be detected as combed for a frame to be
4694 declared combed. See the @option{combpel} parameter description for more info.
4695 Possible values are any number that is a power of 2 starting at 4 and going up
4698 Default value is @code{16}.
4701 The number of combed pixels inside any of the @option{blocky} by
4702 @option{blockx} size blocks on the frame for the frame to be detected as
4703 combed. While @option{cthresh} controls how "visible" the combing must be, this
4704 setting controls "how much" combing there must be in any localized area (a
4705 window defined by the @option{blockx} and @option{blocky} settings) on the
4706 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4707 which point no frames will ever be detected as combed). This setting is known
4708 as @option{MI} in TFM/VFM vocabulary.
4710 Default value is @code{80}.
4713 @anchor{p/c/n/u/b meaning}
4714 @subsection p/c/n/u/b meaning
4716 @subsubsection p/c/n
4718 We assume the following telecined stream:
4721 Top fields: 1 2 2 3 4
4722 Bottom fields: 1 2 3 4 4
4725 The numbers correspond to the progressive frame the fields relate to. Here, the
4726 first two frames are progressive, the 3rd and 4th are combed, and so on.
4728 When @code{fieldmatch} is configured to run a matching from bottom
4729 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4734 B 1 2 3 4 4 <-- matching reference
4743 As a result of the field matching, we can see that some frames get duplicated.
4744 To perform a complete inverse telecine, you need to rely on a decimation filter
4745 after this operation. See for instance the @ref{decimate} filter.
4747 The same operation now matching from top fields (@option{field}=@var{top})
4752 T 1 2 2 3 4 <-- matching reference
4762 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4763 basically, they refer to the frame and field of the opposite parity:
4766 @item @var{p} matches the field of the opposite parity in the previous frame
4767 @item @var{c} matches the field of the opposite parity in the current frame
4768 @item @var{n} matches the field of the opposite parity in the next frame
4773 The @var{u} and @var{b} matching are a bit special in the sense that they match
4774 from the opposite parity flag. In the following examples, we assume that we are
4775 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4776 'x' is placed above and below each matched fields.
4778 With bottom matching (@option{field}=@var{bottom}):
4783 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4784 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4792 With top matching (@option{field}=@var{top}):
4797 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4798 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4806 @subsection Examples
4808 Simple IVTC of a top field first telecined stream:
4810 fieldmatch=order=tff:combmatch=none, decimate
4813 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4815 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4820 Transform the field order of the input video.
4822 It accepts the following parameters:
4827 The output field order. Valid values are @var{tff} for top field first or @var{bff}
4828 for bottom field first.
4831 The default value is @samp{tff}.
4833 The transformation is done by shifting the picture content up or down
4834 by one line, and filling the remaining line with appropriate picture content.
4835 This method is consistent with most broadcast field order converters.
4837 If the input video is not flagged as being interlaced, or it is already
4838 flagged as being of the required output field order, then this filter does
4839 not alter the incoming video.
4841 It is very useful when converting to or from PAL DV material,
4842 which is bottom field first.
4846 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4851 Buffer input images and send them when they are requested.
4853 It is mainly useful when auto-inserted by the libavfilter
4856 It does not take parameters.
4861 Convert the input video to one of the specified pixel formats.
4862 Libavfilter will try to pick one that is suitable as input to
4865 It accepts the following parameters:
4869 A '|'-separated list of pixel format names, such as
4870 "pix_fmts=yuv420p|monow|rgb24".
4874 @subsection Examples
4878 Convert the input video to the @var{yuv420p} format
4880 format=pix_fmts=yuv420p
4883 Convert the input video to any of the formats in the list
4885 format=pix_fmts=yuv420p|yuv444p|yuv410p
4892 Convert the video to specified constant frame rate by duplicating or dropping
4893 frames as necessary.
4895 It accepts the following parameters:
4899 The desired output frame rate. The default is @code{25}.
4904 Possible values are:
4907 zero round towards 0
4911 round towards -infinity
4913 round towards +infinity
4917 The default is @code{near}.
4920 Assume the first PTS should be the given value, in seconds. This allows for
4921 padding/trimming at the start of stream. By default, no assumption is made
4922 about the first frame's expected PTS, so no padding or trimming is done.
4923 For example, this could be set to 0 to pad the beginning with duplicates of
4924 the first frame if a video stream starts after the audio stream or to trim any
4925 frames with a negative PTS.
4929 Alternatively, the options can be specified as a flat string:
4930 @var{fps}[:@var{round}].
4932 See also the @ref{setpts} filter.
4934 @subsection Examples
4938 A typical usage in order to set the fps to 25:
4944 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4946 fps=fps=film:round=near
4952 Pack two different video streams into a stereoscopic video, setting proper
4953 metadata on supported codecs. The two views should have the same size and
4954 framerate and processing will stop when the shorter video ends. Please note
4955 that you may conveniently adjust view properties with the @ref{scale} and
4958 It accepts the following parameters:
4962 The desired packing format. Supported values are:
4967 The views are next to each other (default).
4970 The views are on top of each other.
4973 The views are packed by line.
4976 The views are packed by column.
4979 The views are temporally interleaved.
4988 # Convert left and right views into a frame-sequential video
4989 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
4991 # Convert views into a side-by-side video with the same output resolution as the input
4992 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
4997 Select one frame every N-th frame.
4999 This filter accepts the following option:
5002 Select frame after every @code{step} frames.
5003 Allowed values are positive integers higher than 0. Default value is @code{1}.
5009 Apply a frei0r effect to the input video.
5011 To enable the compilation of this filter, you need to install the frei0r
5012 header and configure FFmpeg with @code{--enable-frei0r}.
5014 It accepts the following parameters:
5019 The name of the frei0r effect to load. If the environment variable
5020 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
5021 directories specified by the colon-separated list in @env{FREIOR_PATH}.
5022 Otherwise, the standard frei0r paths are searched, in this order:
5023 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
5024 @file{/usr/lib/frei0r-1/}.
5027 A '|'-separated list of parameters to pass to the frei0r effect.
5031 A frei0r effect parameter can be a boolean (its value is either
5032 "y" or "n"), a double, a color (specified as
5033 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
5034 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
5035 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
5036 @var{X} and @var{Y} are floating point numbers) and/or a string.
5038 The number and types of parameters depend on the loaded effect. If an
5039 effect parameter is not specified, the default value is set.
5041 @subsection Examples
5045 Apply the distort0r effect, setting the first two double parameters:
5047 frei0r=filter_name=distort0r:filter_params=0.5|0.01
5051 Apply the colordistance effect, taking a color as the first parameter:
5053 frei0r=colordistance:0.2/0.3/0.4
5054 frei0r=colordistance:violet
5055 frei0r=colordistance:0x112233
5059 Apply the perspective effect, specifying the top left and top right image
5062 frei0r=perspective:0.2/0.2|0.8/0.2
5066 For more information, see
5067 @url{http://frei0r.dyne.org}
5071 The filter accepts the following options:
5075 Set the luminance expression.
5077 Set the chrominance blue expression.
5079 Set the chrominance red expression.
5081 Set the alpha expression.
5083 Set the red expression.
5085 Set the green expression.
5087 Set the blue expression.
5090 The colorspace is selected according to the specified options. If one
5091 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
5092 options is specified, the filter will automatically select a YCbCr
5093 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
5094 @option{blue_expr} options is specified, it will select an RGB
5097 If one of the chrominance expression is not defined, it falls back on the other
5098 one. If no alpha expression is specified it will evaluate to opaque value.
5099 If none of chrominance expressions are specified, they will evaluate
5100 to the luminance expression.
5102 The expressions can use the following variables and functions:
5106 The sequential number of the filtered frame, starting from @code{0}.
5110 The coordinates of the current sample.
5114 The width and height of the image.
5118 Width and height scale depending on the currently filtered plane. It is the
5119 ratio between the corresponding luma plane number of pixels and the current
5120 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
5121 @code{0.5,0.5} for chroma planes.
5124 Time of the current frame, expressed in seconds.
5127 Return the value of the pixel at location (@var{x},@var{y}) of the current
5131 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
5135 Return the value of the pixel at location (@var{x},@var{y}) of the
5136 blue-difference chroma plane. Return 0 if there is no such plane.
5139 Return the value of the pixel at location (@var{x},@var{y}) of the
5140 red-difference chroma plane. Return 0 if there is no such plane.
5145 Return the value of the pixel at location (@var{x},@var{y}) of the
5146 red/green/blue component. Return 0 if there is no such component.
5149 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
5150 plane. Return 0 if there is no such plane.
5153 For functions, if @var{x} and @var{y} are outside the area, the value will be
5154 automatically clipped to the closer edge.
5156 @subsection Examples
5160 Flip the image horizontally:
5166 Generate a bidimensional sine wave, with angle @code{PI/3} and a
5167 wavelength of 100 pixels:
5169 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
5173 Generate a fancy enigmatic moving light:
5175 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
5179 Generate a quick emboss effect:
5181 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
5185 Modify RGB components depending on pixel position:
5187 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
5191 Create a radial gradient that is the same size as the input (also see
5192 the @ref{vignette} filter):
5194 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
5198 Create a linear gradient to use as a mask for another filter, then
5199 compose with @ref{overlay}. In this example the video will gradually
5200 become more blurry from the top to the bottom of the y-axis as defined
5201 by the linear gradient:
5203 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
5209 Fix the banding artifacts that are sometimes introduced into nearly flat
5210 regions by truncation to 8bit color depth.
5211 Interpolate the gradients that should go where the bands are, and
5214 It is designed for playback only. Do not use it prior to
5215 lossy compression, because compression tends to lose the dither and
5216 bring back the bands.
5218 It accepts the following parameters:
5223 The maximum amount by which the filter will change any one pixel. This is also
5224 the threshold for detecting nearly flat regions. Acceptable values range from
5225 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
5229 The neighborhood to fit the gradient to. A larger radius makes for smoother
5230 gradients, but also prevents the filter from modifying the pixels near detailed
5231 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
5232 values will be clipped to the valid range.
5236 Alternatively, the options can be specified as a flat string:
5237 @var{strength}[:@var{radius}]
5239 @subsection Examples
5243 Apply the filter with a @code{3.5} strength and radius of @code{8}:
5249 Specify radius, omitting the strength (which will fall-back to the default
5260 Apply a Hald CLUT to a video stream.
5262 First input is the video stream to process, and second one is the Hald CLUT.
5263 The Hald CLUT input can be a simple picture or a complete video stream.
5265 The filter accepts the following options:
5269 Force termination when the shortest input terminates. Default is @code{0}.
5271 Continue applying the last CLUT after the end of the stream. A value of
5272 @code{0} disable the filter after the last frame of the CLUT is reached.
5273 Default is @code{1}.
5276 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
5277 filters share the same internals).
5279 More information about the Hald CLUT can be found on Eskil Steenberg's website
5280 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
5282 @subsection Workflow examples
5284 @subsubsection Hald CLUT video stream
5286 Generate an identity Hald CLUT stream altered with various effects:
5288 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
5291 Note: make sure you use a lossless codec.
5293 Then use it with @code{haldclut} to apply it on some random stream:
5295 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
5298 The Hald CLUT will be applied to the 10 first seconds (duration of
5299 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
5300 to the remaining frames of the @code{mandelbrot} stream.
5302 @subsubsection Hald CLUT with preview
5304 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
5305 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
5306 biggest possible square starting at the top left of the picture. The remaining
5307 padding pixels (bottom or right) will be ignored. This area can be used to add
5308 a preview of the Hald CLUT.
5310 Typically, the following generated Hald CLUT will be supported by the
5311 @code{haldclut} filter:
5314 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
5315 pad=iw+320 [padded_clut];
5316 smptebars=s=320x256, split [a][b];
5317 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
5318 [main][b] overlay=W-320" -frames:v 1 clut.png
5321 It contains the original and a preview of the effect of the CLUT: SMPTE color
5322 bars are displayed on the right-top, and below the same color bars processed by
5325 Then, the effect of this Hald CLUT can be visualized with:
5327 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
5332 Flip the input video horizontally.
5334 For example, to horizontally flip the input video with @command{ffmpeg}:
5336 ffmpeg -i in.avi -vf "hflip" out.avi
5340 This filter applies a global color histogram equalization on a
5343 It can be used to correct video that has a compressed range of pixel
5344 intensities. The filter redistributes the pixel intensities to
5345 equalize their distribution across the intensity range. It may be
5346 viewed as an "automatically adjusting contrast filter". This filter is
5347 useful only for correcting degraded or poorly captured source
5350 The filter accepts the following options:
5354 Determine the amount of equalization to be applied. As the strength
5355 is reduced, the distribution of pixel intensities more-and-more
5356 approaches that of the input frame. The value must be a float number
5357 in the range [0,1] and defaults to 0.200.
5360 Set the maximum intensity that can generated and scale the output
5361 values appropriately. The strength should be set as desired and then
5362 the intensity can be limited if needed to avoid washing-out. The value
5363 must be a float number in the range [0,1] and defaults to 0.210.
5366 Set the antibanding level. If enabled the filter will randomly vary
5367 the luminance of output pixels by a small amount to avoid banding of
5368 the histogram. Possible values are @code{none}, @code{weak} or
5369 @code{strong}. It defaults to @code{none}.
5374 Compute and draw a color distribution histogram for the input video.
5376 The computed histogram is a representation of the color component
5377 distribution in an image.
5379 The filter accepts the following options:
5385 It accepts the following values:
5388 Standard histogram that displays the color components distribution in an
5389 image. Displays color graph for each color component. Shows distribution of
5390 the Y, U, V, A or R, G, B components, depending on input format, in the
5391 current frame. Below each graph a color component scale meter is shown.
5394 Displays chroma values (U/V color placement) in a two dimensional
5395 graph (which is called a vectorscope). The brighter a pixel in the
5396 vectorscope, the more pixels of the input frame correspond to that pixel
5397 (i.e., more pixels have this chroma value). The V component is displayed on
5398 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5399 side being V = 255. The U component is displayed on the vertical (Y) axis,
5400 with the top representing U = 0 and the bottom representing U = 255.
5402 The position of a white pixel in the graph corresponds to the chroma value of
5403 a pixel of the input clip. The graph can therefore be used to read the hue
5404 (color flavor) and the saturation (the dominance of the hue in the color). As
5405 the hue of a color changes, it moves around the square. At the center of the
5406 square the saturation is zero, which means that the corresponding pixel has no
5407 color. If the amount of a specific color is increased (while leaving the other
5408 colors unchanged) the saturation increases, and the indicator moves towards
5409 the edge of the square.
5412 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5416 Per row/column color component graph. In row mode, the graph on the left side
5417 represents color component value 0 and the right side represents value = 255.
5418 In column mode, the top side represents color component value = 0 and bottom
5419 side represents value = 255.
5421 Default value is @code{levels}.
5424 Set height of level in @code{levels}. Default value is @code{200}.
5425 Allowed range is [50, 2048].
5428 Set height of color scale in @code{levels}. Default value is @code{12}.
5429 Allowed range is [0, 40].
5432 Set step for @code{waveform} mode. Smaller values are useful to find out how
5433 many values of the same luminance are distributed across input rows/columns.
5434 Default value is @code{10}. Allowed range is [1, 255].
5437 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5438 Default is @code{row}.
5440 @item waveform_mirror
5441 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5442 means mirrored. In mirrored mode, higher values will be represented on the left
5443 side for @code{row} mode and at the top for @code{column} mode. Default is
5444 @code{0} (unmirrored).
5447 Set display mode for @code{waveform} and @code{levels}.
5448 It accepts the following values:
5451 Display separate graph for the color components side by side in
5452 @code{row} waveform mode or one below the other in @code{column} waveform mode
5453 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5454 per color component graphs are placed below each other.
5456 Using this display mode in @code{waveform} histogram mode makes it easy to
5457 spot color casts in the highlights and shadows of an image, by comparing the
5458 contours of the top and the bottom graphs of each waveform. Since whites,
5459 grays, and blacks are characterized by exactly equal amounts of red, green,
5460 and blue, neutral areas of the picture should display three waveforms of
5461 roughly equal width/height. If not, the correction is easy to perform by
5462 making level adjustments the three waveforms.
5465 Presents information identical to that in the @code{parade}, except
5466 that the graphs representing color components are superimposed directly
5469 This display mode in @code{waveform} histogram mode makes it easier to spot
5470 relative differences or similarities in overlapping areas of the color
5471 components that are supposed to be identical, such as neutral whites, grays,
5474 Default is @code{parade}.
5477 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5478 Default is @code{linear}.
5481 @subsection Examples
5486 Calculate and draw histogram:
5488 ffplay -i input -vf histogram
5496 This is a high precision/quality 3d denoise filter. It aims to reduce
5497 image noise, producing smooth images and making still images really
5498 still. It should enhance compressibility.
5500 It accepts the following optional parameters:
5504 A non-negative floating point number which specifies spatial luma strength.
5507 @item chroma_spatial
5508 A non-negative floating point number which specifies spatial chroma strength.
5509 It defaults to 3.0*@var{luma_spatial}/4.0.
5512 A floating point number which specifies luma temporal strength. It defaults to
5513 6.0*@var{luma_spatial}/4.0.
5516 A floating point number which specifies chroma temporal strength. It defaults to
5517 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5522 Apply a high-quality magnification filter designed for pixel art. This filter
5523 was originally created by Maxim Stepin.
5525 It accepts the following option:
5529 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
5530 @code{hq3x} and @code{4} for @code{hq4x}.
5531 Default is @code{3}.
5536 Modify the hue and/or the saturation of the input.
5538 It accepts the following parameters:
5542 Specify the hue angle as a number of degrees. It accepts an expression,
5543 and defaults to "0".
5546 Specify the saturation in the [-10,10] range. It accepts an expression and
5550 Specify the hue angle as a number of radians. It accepts an
5551 expression, and defaults to "0".
5554 Specify the brightness in the [-10,10] range. It accepts an expression and
5558 @option{h} and @option{H} are mutually exclusive, and can't be
5559 specified at the same time.
5561 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5562 expressions containing the following constants:
5566 frame count of the input frame starting from 0
5569 presentation timestamp of the input frame expressed in time base units
5572 frame rate of the input video, NAN if the input frame rate is unknown
5575 timestamp expressed in seconds, NAN if the input timestamp is unknown
5578 time base of the input video
5581 @subsection Examples
5585 Set the hue to 90 degrees and the saturation to 1.0:
5591 Same command but expressing the hue in radians:
5597 Rotate hue and make the saturation swing between 0
5598 and 2 over a period of 1 second:
5600 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5604 Apply a 3 seconds saturation fade-in effect starting at 0:
5609 The general fade-in expression can be written as:
5611 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5615 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5617 hue="s=max(0\, min(1\, (8-t)/3))"
5620 The general fade-out expression can be written as:
5622 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5627 @subsection Commands
5629 This filter supports the following commands:
5635 Modify the hue and/or the saturation and/or brightness of the input video.
5636 The command accepts the same syntax of the corresponding option.
5638 If the specified expression is not valid, it is kept at its current
5644 Detect video interlacing type.
5646 This filter tries to detect if the input frames as interlaced, progressive,
5647 top or bottom field first. It will also try and detect fields that are
5648 repeated between adjacent frames (a sign of telecine).
5650 Single frame detection considers only immediately adjacent frames when classifying each frame.
5651 Multiple frame detection incorporates the classification history of previous frames.
5653 The filter will log these metadata values:
5656 @item single.current_frame
5657 Detected type of current frame using single-frame detection. One of:
5658 ``tff'' (top field first), ``bff'' (bottom field first),
5659 ``progressive'', or ``undetermined''
5662 Cumulative number of frames detected as top field first using single-frame detection.
5665 Cumulative number of frames detected as top field first using multiple-frame detection.
5668 Cumulative number of frames detected as bottom field first using single-frame detection.
5670 @item multiple.current_frame
5671 Detected type of current frame using multiple-frame detection. One of:
5672 ``tff'' (top field first), ``bff'' (bottom field first),
5673 ``progressive'', or ``undetermined''
5676 Cumulative number of frames detected as bottom field first using multiple-frame detection.
5678 @item single.progressive
5679 Cumulative number of frames detected as progressive using single-frame detection.
5681 @item multiple.progressive
5682 Cumulative number of frames detected as progressive using multiple-frame detection.
5684 @item single.undetermined
5685 Cumulative number of frames that could not be classified using single-frame detection.
5687 @item multiple.undetermined
5688 Cumulative number of frames that could not be classified using multiple-frame detection.
5690 @item repeated.current_frame
5691 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
5693 @item repeated.neither
5694 Cumulative number of frames with no repeated field.
5697 Cumulative number of frames with the top field repeated from the previous frame's top field.
5699 @item repeated.bottom
5700 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
5703 The filter accepts the following options:
5707 Set interlacing threshold.
5709 Set progressive threshold.
5711 Threshold for repeated field detection.
5713 Number of frames after which a given frame's contribution to the
5714 statistics is halved (i.e., it contributes only 0.5 to it's
5715 classification). The default of 0 means that all frames seen are given
5716 full weight of 1.0 forever.
5721 Deinterleave or interleave fields.
5723 This filter allows one to process interlaced images fields without
5724 deinterlacing them. Deinterleaving splits the input frame into 2
5725 fields (so called half pictures). Odd lines are moved to the top
5726 half of the output image, even lines to the bottom half.
5727 You can process (filter) them independently and then re-interleave them.
5729 The filter accepts the following options:
5733 @item chroma_mode, c
5735 Available values for @var{luma_mode}, @var{chroma_mode} and
5736 @var{alpha_mode} are:
5742 @item deinterleave, d
5743 Deinterleave fields, placing one above the other.
5746 Interleave fields. Reverse the effect of deinterleaving.
5748 Default value is @code{none}.
5751 @item chroma_swap, cs
5752 @item alpha_swap, as
5753 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5758 Simple interlacing filter from progressive contents. This interleaves upper (or
5759 lower) lines from odd frames with lower (or upper) lines from even frames,
5760 halving the frame rate and preserving image height.
5763 Original Original New Frame
5764 Frame 'j' Frame 'j+1' (tff)
5765 ========== =========== ==================
5766 Line 0 --------------------> Frame 'j' Line 0
5767 Line 1 Line 1 ----> Frame 'j+1' Line 1
5768 Line 2 ---------------------> Frame 'j' Line 2
5769 Line 3 Line 3 ----> Frame 'j+1' Line 3
5771 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5774 It accepts the following optional parameters:
5778 This determines whether the interlaced frame is taken from the even
5779 (tff - default) or odd (bff) lines of the progressive frame.
5782 Enable (default) or disable the vertical lowpass filter to avoid twitter
5783 interlacing and reduce moire patterns.
5788 Deinterlace input video by applying Donald Graft's adaptive kernel
5789 deinterling. Work on interlaced parts of a video to produce
5792 The description of the accepted parameters follows.
5796 Set the threshold which affects the filter's tolerance when
5797 determining if a pixel line must be processed. It must be an integer
5798 in the range [0,255] and defaults to 10. A value of 0 will result in
5799 applying the process on every pixels.
5802 Paint pixels exceeding the threshold value to white if set to 1.
5806 Set the fields order. Swap fields if set to 1, leave fields alone if
5810 Enable additional sharpening if set to 1. Default is 0.
5813 Enable twoway sharpening if set to 1. Default is 0.
5816 @subsection Examples
5820 Apply default values:
5822 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5826 Enable additional sharpening:
5832 Paint processed pixels in white:
5838 @section lenscorrection
5840 Correct radial lens distortion
5842 This filter can be used to correct for radial distortion as can result from the use
5843 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
5844 one can use tools available for example as part of opencv or simply trial-and-error.
5845 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
5846 and extract the k1 and k2 coefficients from the resulting matrix.
5848 Note that effectively the same filter is available in the open-source tools Krita and
5849 Digikam from the KDE project.
5851 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
5852 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
5853 brightness distribution, so you may want to use both filters together in certain
5854 cases, though you will have to take care of ordering, i.e. whether vignetting should
5855 be applied before or after lens correction.
5859 The filter accepts the following options:
5863 Relative x-coordinate of the focal point of the image, and thereby the center of the
5864 distortion. This value has a range [0,1] and is expressed as fractions of the image
5867 Relative y-coordinate of the focal point of the image, and thereby the center of the
5868 distortion. This value has a range [0,1] and is expressed as fractions of the image
5871 Coefficient of the quadratic correction term. 0.5 means no correction.
5873 Coefficient of the double quadratic correction term. 0.5 means no correction.
5876 The formula that generates the correction is:
5878 @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)
5880 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
5881 distances from the focal point in the source and target images, respectively.
5886 Apply a 3D LUT to an input video.
5888 The filter accepts the following options:
5892 Set the 3D LUT file name.
5894 Currently supported formats:
5906 Select interpolation mode.
5908 Available values are:
5912 Use values from the nearest defined point.
5914 Interpolate values using the 8 points defining a cube.
5916 Interpolate values using a tetrahedron.
5920 @section lut, lutrgb, lutyuv
5922 Compute a look-up table for binding each pixel component input value
5923 to an output value, and apply it to the input video.
5925 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5926 to an RGB input video.
5928 These filters accept the following parameters:
5931 set first pixel component expression
5933 set second pixel component expression
5935 set third pixel component expression
5937 set fourth pixel component expression, corresponds to the alpha component
5940 set red component expression
5942 set green component expression
5944 set blue component expression
5946 alpha component expression
5949 set Y/luminance component expression
5951 set U/Cb component expression
5953 set V/Cr component expression
5956 Each of them specifies the expression to use for computing the lookup table for
5957 the corresponding pixel component values.
5959 The exact component associated to each of the @var{c*} options depends on the
5962 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5963 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5965 The expressions can contain the following constants and functions:
5970 The input width and height.
5973 The input value for the pixel component.
5976 The input value, clipped to the @var{minval}-@var{maxval} range.
5979 The maximum value for the pixel component.
5982 The minimum value for the pixel component.
5985 The negated value for the pixel component value, clipped to the
5986 @var{minval}-@var{maxval} range; it corresponds to the expression
5987 "maxval-clipval+minval".
5990 The computed value in @var{val}, clipped to the
5991 @var{minval}-@var{maxval} range.
5993 @item gammaval(gamma)
5994 The computed gamma correction value of the pixel component value,
5995 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
5997 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
6001 All expressions default to "val".
6003 @subsection Examples
6009 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
6010 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
6013 The above is the same as:
6015 lutrgb="r=negval:g=negval:b=negval"
6016 lutyuv="y=negval:u=negval:v=negval"
6026 Remove chroma components, turning the video into a graytone image:
6028 lutyuv="u=128:v=128"
6032 Apply a luma burning effect:
6038 Remove green and blue components:
6044 Set a constant alpha channel value on input:
6046 format=rgba,lutrgb=a="maxval-minval/2"
6050 Correct luminance gamma by a factor of 0.5:
6052 lutyuv=y=gammaval(0.5)
6056 Discard least significant bits of luma:
6058 lutyuv=y='bitand(val, 128+64+32)'
6062 @section mergeplanes
6064 Merge color channel components from several video streams.
6066 The filter accepts up to 4 input streams, and merge selected input
6067 planes to the output video.
6069 This filter accepts the following options:
6072 Set input to output plane mapping. Default is @code{0}.
6074 The mappings is specified as a bitmap. It should be specified as a
6075 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
6076 mapping for the first plane of the output stream. 'A' sets the number of
6077 the input stream to use (from 0 to 3), and 'a' the plane number of the
6078 corresponding input to use (from 0 to 3). The rest of the mappings is
6079 similar, 'Bb' describes the mapping for the output stream second
6080 plane, 'Cc' describes the mapping for the output stream third plane and
6081 'Dd' describes the mapping for the output stream fourth plane.
6084 Set output pixel format. Default is @code{yuva444p}.
6087 @subsection Examples
6091 Merge three gray video streams of same width and height into single video stream:
6093 [a0][a1][a2]mergeplanes=0x001020:yuv444p
6097 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
6099 [a0][a1]mergeplanes=0x00010210:yuva444p
6103 Swap Y and A plane in yuva444p stream:
6105 format=yuva444p,mergeplanes=0x03010200:yuva444p
6109 Swap U and V plane in yuv420p stream:
6111 format=yuv420p,mergeplanes=0x000201:yuv420p
6115 Cast a rgb24 clip to yuv444p:
6117 format=rgb24,mergeplanes=0x000102:yuv444p
6123 Apply motion-compensation deinterlacing.
6125 It needs one field per frame as input and must thus be used together
6126 with yadif=1/3 or equivalent.
6128 This filter accepts the following options:
6131 Set the deinterlacing mode.
6133 It accepts one of the following values:
6138 use iterative motion estimation
6140 like @samp{slow}, but use multiple reference frames.
6142 Default value is @samp{fast}.
6145 Set the picture field parity assumed for the input video. It must be
6146 one of the following values:
6150 assume top field first
6152 assume bottom field first
6155 Default value is @samp{bff}.
6158 Set per-block quantization parameter (QP) used by the internal
6161 Higher values should result in a smoother motion vector field but less
6162 optimal individual vectors. Default value is 1.
6167 Apply an MPlayer filter to the input video.
6169 This filter provides a wrapper around some of the filters of
6172 This wrapper is considered experimental. Some of the wrapped filters
6173 may not work properly and we may drop support for them, as they will
6174 be implemented natively into FFmpeg. Thus you should avoid
6175 depending on them when writing portable scripts.
6177 The filter accepts the parameters:
6178 @var{filter_name}[:=]@var{filter_params}
6180 @var{filter_name} is the name of a supported MPlayer filter,
6181 @var{filter_params} is a string containing the parameters accepted by
6184 The list of the currently supported filters follows:
6194 The parameter syntax and behavior for the listed filters are the same
6195 of the corresponding MPlayer filters. For detailed instructions check
6196 the "VIDEO FILTERS" section in the MPlayer manual.
6198 @subsection Examples
6202 Adjust gamma, brightness, contrast:
6208 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
6212 Drop frames that do not differ greatly from the previous frame in
6213 order to reduce frame rate.
6215 The main use of this filter is for very-low-bitrate encoding
6216 (e.g. streaming over dialup modem), but it could in theory be used for
6217 fixing movies that were inverse-telecined incorrectly.
6219 A description of the accepted options follows.
6223 Set the maximum number of consecutive frames which can be dropped (if
6224 positive), or the minimum interval between dropped frames (if
6225 negative). If the value is 0, the frame is dropped unregarding the
6226 number of previous sequentially dropped frames.
6233 Set the dropping threshold values.
6235 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
6236 represent actual pixel value differences, so a threshold of 64
6237 corresponds to 1 unit of difference for each pixel, or the same spread
6238 out differently over the block.
6240 A frame is a candidate for dropping if no 8x8 blocks differ by more
6241 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
6242 meaning the whole image) differ by more than a threshold of @option{lo}.
6244 Default value for @option{hi} is 64*12, default value for @option{lo} is
6245 64*5, and default value for @option{frac} is 0.33.
6253 It accepts an integer in input; if non-zero it negates the
6254 alpha component (if available). The default value in input is 0.
6258 Force libavfilter not to use any of the specified pixel formats for the
6259 input to the next filter.
6261 It accepts the following parameters:
6265 A '|'-separated list of pixel format names, such as
6266 apix_fmts=yuv420p|monow|rgb24".
6270 @subsection Examples
6274 Force libavfilter to use a format different from @var{yuv420p} for the
6275 input to the vflip filter:
6277 noformat=pix_fmts=yuv420p,vflip
6281 Convert the input video to any of the formats not contained in the list:
6283 noformat=yuv420p|yuv444p|yuv410p
6289 Add noise on video input frame.
6291 The filter accepts the following options:
6299 Set noise seed for specific pixel component or all pixel components in case
6300 of @var{all_seed}. Default value is @code{123457}.
6302 @item all_strength, alls
6303 @item c0_strength, c0s
6304 @item c1_strength, c1s
6305 @item c2_strength, c2s
6306 @item c3_strength, c3s
6307 Set noise strength for specific pixel component or all pixel components in case
6308 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
6310 @item all_flags, allf
6315 Set pixel component flags or set flags for all components if @var{all_flags}.
6316 Available values for component flags are:
6319 averaged temporal noise (smoother)
6321 mix random noise with a (semi)regular pattern
6323 temporal noise (noise pattern changes between frames)
6325 uniform noise (gaussian otherwise)
6329 @subsection Examples
6331 Add temporal and uniform noise to input video:
6333 noise=alls=20:allf=t+u
6338 Pass the video source unchanged to the output.
6342 Apply a video transform using libopencv.
6344 To enable this filter, install the libopencv library and headers and
6345 configure FFmpeg with @code{--enable-libopencv}.
6347 It accepts the following parameters:
6352 The name of the libopencv filter to apply.
6355 The parameters to pass to the libopencv filter. If not specified, the default
6360 Refer to the official libopencv documentation for more precise
6362 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
6364 Several libopencv filters are supported; see the following subsections.
6369 Dilate an image by using a specific structuring element.
6370 It corresponds to the libopencv function @code{cvDilate}.
6372 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
6374 @var{struct_el} represents a structuring element, and has the syntax:
6375 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
6377 @var{cols} and @var{rows} represent the number of columns and rows of
6378 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
6379 point, and @var{shape} the shape for the structuring element. @var{shape}
6380 must be "rect", "cross", "ellipse", or "custom".
6382 If the value for @var{shape} is "custom", it must be followed by a
6383 string of the form "=@var{filename}". The file with name
6384 @var{filename} is assumed to represent a binary image, with each
6385 printable character corresponding to a bright pixel. When a custom
6386 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
6387 or columns and rows of the read file are assumed instead.
6389 The default value for @var{struct_el} is "3x3+0x0/rect".
6391 @var{nb_iterations} specifies the number of times the transform is
6392 applied to the image, and defaults to 1.
6396 # Use the default values
6399 # Dilate using a structuring element with a 5x5 cross, iterating two times
6400 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
6402 # Read the shape from the file diamond.shape, iterating two times.
6403 # The file diamond.shape may contain a pattern of characters like this
6409 # The specified columns and rows are ignored
6410 # but the anchor point coordinates are not
6411 ocv=dilate:0x0+2x2/custom=diamond.shape|2
6416 Erode an image by using a specific structuring element.
6417 It corresponds to the libopencv function @code{cvErode}.
6419 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
6420 with the same syntax and semantics as the @ref{dilate} filter.
6424 Smooth the input video.
6426 The filter takes the following parameters:
6427 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
6429 @var{type} is the type of smooth filter to apply, and must be one of
6430 the following values: "blur", "blur_no_scale", "median", "gaussian",
6431 or "bilateral". The default value is "gaussian".
6433 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
6434 depend on the smooth type. @var{param1} and
6435 @var{param2} accept integer positive values or 0. @var{param3} and
6436 @var{param4} accept floating point values.
6438 The default value for @var{param1} is 3. The default value for the
6439 other parameters is 0.
6441 These parameters correspond to the parameters assigned to the
6442 libopencv function @code{cvSmooth}.
6447 Overlay one video on top of another.
6449 It takes two inputs and has one output. The first input is the "main"
6450 video on which the second input is overlaid.
6452 It accepts the following parameters:
6454 A description of the accepted options follows.
6459 Set the expression for the x and y coordinates of the overlaid video
6460 on the main video. Default value is "0" for both expressions. In case
6461 the expression is invalid, it is set to a huge value (meaning that the
6462 overlay will not be displayed within the output visible area).
6465 The action to take when EOF is encountered on the secondary input; it accepts
6466 one of the following values:
6470 Repeat the last frame (the default).
6474 Pass the main input through.
6478 Set when the expressions for @option{x}, and @option{y} are evaluated.
6480 It accepts the following values:
6483 only evaluate expressions once during the filter initialization or
6484 when a command is processed
6487 evaluate expressions for each incoming frame
6490 Default value is @samp{frame}.
6493 If set to 1, force the output to terminate when the shortest input
6494 terminates. Default value is 0.
6497 Set the format for the output video.
6499 It accepts the following values:
6514 Default value is @samp{yuv420}.
6516 @item rgb @emph{(deprecated)}
6517 If set to 1, force the filter to accept inputs in the RGB
6518 color space. Default value is 0. This option is deprecated, use
6519 @option{format} instead.
6522 If set to 1, force the filter to draw the last overlay frame over the
6523 main input until the end of the stream. A value of 0 disables this
6524 behavior. Default value is 1.
6527 The @option{x}, and @option{y} expressions can contain the following
6533 The main input width and height.
6537 The overlay input width and height.
6541 The computed values for @var{x} and @var{y}. They are evaluated for
6546 horizontal and vertical chroma subsample values of the output
6547 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6551 the number of input frame, starting from 0
6554 the position in the file of the input frame, NAN if unknown
6557 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6561 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6562 when evaluation is done @emph{per frame}, and will evaluate to NAN
6563 when @option{eval} is set to @samp{init}.
6565 Be aware that frames are taken from each input video in timestamp
6566 order, hence, if their initial timestamps differ, it is a good idea
6567 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6568 have them begin in the same zero timestamp, as the example for
6569 the @var{movie} filter does.
6571 You can chain together more overlays but you should test the
6572 efficiency of such approach.
6574 @subsection Commands
6576 This filter supports the following commands:
6580 Modify the x and y of the overlay input.
6581 The command accepts the same syntax of the corresponding option.
6583 If the specified expression is not valid, it is kept at its current
6587 @subsection Examples
6591 Draw the overlay at 10 pixels from the bottom right corner of the main
6594 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6597 Using named options the example above becomes:
6599 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6603 Insert a transparent PNG logo in the bottom left corner of the input,
6604 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6606 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6610 Insert 2 different transparent PNG logos (second logo on bottom
6611 right corner) using the @command{ffmpeg} tool:
6613 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
6617 Add a transparent color layer on top of the main video; @code{WxH}
6618 must specify the size of the main input to the overlay filter:
6620 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6624 Play an original video and a filtered version (here with the deshake
6625 filter) side by side using the @command{ffplay} tool:
6627 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6630 The above command is the same as:
6632 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6636 Make a sliding overlay appearing from the left to the right top part of the
6637 screen starting since time 2:
6639 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6643 Compose output by putting two input videos side to side:
6645 ffmpeg -i left.avi -i right.avi -filter_complex "
6646 nullsrc=size=200x100 [background];
6647 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6648 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6649 [background][left] overlay=shortest=1 [background+left];
6650 [background+left][right] overlay=shortest=1:x=100 [left+right]
6655 Mask 10-20 seconds of a video by applying the delogo filter to a section
6657 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6658 -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]'
6663 Chain several overlays in cascade:
6665 nullsrc=s=200x200 [bg];
6666 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6667 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6668 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6669 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6670 [in3] null, [mid2] overlay=100:100 [out0]
6677 Apply Overcomplete Wavelet denoiser.
6679 The filter accepts the following options:
6685 Larger depth values will denoise lower frequency components more, but
6686 slow down filtering.
6688 Must be an int in the range 8-16, default is @code{8}.
6690 @item luma_strength, ls
6693 Must be a double value in the range 0-1000, default is @code{1.0}.
6695 @item chroma_strength, cs
6696 Set chroma strength.
6698 Must be a double value in the range 0-1000, default is @code{1.0}.
6703 Add paddings to the input image, and place the original input at the
6704 provided @var{x}, @var{y} coordinates.
6706 It accepts the following parameters:
6711 Specify an expression for the size of the output image with the
6712 paddings added. If the value for @var{width} or @var{height} is 0, the
6713 corresponding input size is used for the output.
6715 The @var{width} expression can reference the value set by the
6716 @var{height} expression, and vice versa.
6718 The default value of @var{width} and @var{height} is 0.
6722 Specify the offsets to place the input image at within the padded area,
6723 with respect to the top/left border of the output image.
6725 The @var{x} expression can reference the value set by the @var{y}
6726 expression, and vice versa.
6728 The default value of @var{x} and @var{y} is 0.
6731 Specify the color of the padded area. For the syntax of this option,
6732 check the "Color" section in the ffmpeg-utils manual.
6734 The default value of @var{color} is "black".
6737 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6738 options are expressions containing the following constants:
6743 The input video width and height.
6747 These are the same as @var{in_w} and @var{in_h}.
6751 The output width and height (the size of the padded area), as
6752 specified by the @var{width} and @var{height} expressions.
6756 These are the same as @var{out_w} and @var{out_h}.
6760 The x and y offsets as specified by the @var{x} and @var{y}
6761 expressions, or NAN if not yet specified.
6764 same as @var{iw} / @var{ih}
6767 input sample aspect ratio
6770 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6774 The horizontal and vertical chroma subsample values. For example for the
6775 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6778 @subsection Examples
6782 Add paddings with the color "violet" to the input video. The output video
6783 size is 640x480, and the top-left corner of the input video is placed at
6786 pad=640:480:0:40:violet
6789 The example above is equivalent to the following command:
6791 pad=width=640:height=480:x=0:y=40:color=violet
6795 Pad the input to get an output with dimensions increased by 3/2,
6796 and put the input video at the center of the padded area:
6798 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6802 Pad the input to get a squared output with size equal to the maximum
6803 value between the input width and height, and put the input video at
6804 the center of the padded area:
6806 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6810 Pad the input to get a final w/h ratio of 16:9:
6812 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6816 In case of anamorphic video, in order to set the output display aspect
6817 correctly, it is necessary to use @var{sar} in the expression,
6818 according to the relation:
6820 (ih * X / ih) * sar = output_dar
6821 X = output_dar / sar
6824 Thus the previous example needs to be modified to:
6826 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6830 Double the output size and put the input video in the bottom-right
6831 corner of the output padded area:
6833 pad="2*iw:2*ih:ow-iw:oh-ih"
6837 @section perspective
6839 Correct perspective of video not recorded perpendicular to the screen.
6841 A description of the accepted parameters follows.
6852 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6853 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6854 If the @code{sense} option is set to @code{source}, then the specified points will be sent
6855 to the corners of the destination. If the @code{sense} option is set to @code{destination},
6856 then the corners of the source will be sent to the specified coordinates.
6858 The expressions can use the following variables:
6863 the width and height of video frame.
6867 Set interpolation for perspective correction.
6869 It accepts the following values:
6875 Default value is @samp{linear}.
6878 Set interpretation of coordinate options.
6880 It accepts the following values:
6884 Send point in the source specified by the given coordinates to
6885 the corners of the destination.
6887 @item 1, destination
6889 Send the corners of the source to the point in the destination specified
6890 by the given coordinates.
6892 Default value is @samp{source}.
6898 Delay interlaced video by one field time so that the field order changes.
6900 The intended use is to fix PAL movies that have been captured with the
6901 opposite field order to the film-to-video transfer.
6903 A description of the accepted parameters follows.
6909 It accepts the following values:
6912 Capture field order top-first, transfer bottom-first.
6913 Filter will delay the bottom field.
6916 Capture field order bottom-first, transfer top-first.
6917 Filter will delay the top field.
6920 Capture and transfer with the same field order. This mode only exists
6921 for the documentation of the other options to refer to, but if you
6922 actually select it, the filter will faithfully do nothing.
6925 Capture field order determined automatically by field flags, transfer
6927 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6928 basis using field flags. If no field information is available,
6929 then this works just like @samp{u}.
6932 Capture unknown or varying, transfer opposite.
6933 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6934 analyzing the images and selecting the alternative that produces best
6935 match between the fields.
6938 Capture top-first, transfer unknown or varying.
6939 Filter selects among @samp{t} and @samp{p} using image analysis.
6942 Capture bottom-first, transfer unknown or varying.
6943 Filter selects among @samp{b} and @samp{p} using image analysis.
6946 Capture determined by field flags, transfer unknown or varying.
6947 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6948 image analysis. If no field information is available, then this works just
6949 like @samp{U}. This is the default mode.
6952 Both capture and transfer unknown or varying.
6953 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
6957 @section pixdesctest
6959 Pixel format descriptor test filter, mainly useful for internal
6960 testing. The output video should be equal to the input video.
6964 format=monow, pixdesctest
6967 can be used to test the monowhite pixel format descriptor definition.
6971 Enable the specified chain of postprocessing subfilters using libpostproc. This
6972 library should be automatically selected with a GPL build (@code{--enable-gpl}).
6973 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
6974 Each subfilter and some options have a short and a long name that can be used
6975 interchangeably, i.e. dr/dering are the same.
6977 The filters accept the following options:
6981 Set postprocessing subfilters string.
6984 All subfilters share common options to determine their scope:
6988 Honor the quality commands for this subfilter.
6991 Do chrominance filtering, too (default).
6994 Do luminance filtering only (no chrominance).
6997 Do chrominance filtering only (no luminance).
7000 These options can be appended after the subfilter name, separated by a '|'.
7002 Available subfilters are:
7005 @item hb/hdeblock[|difference[|flatness]]
7006 Horizontal deblocking filter
7009 Difference factor where higher values mean more deblocking (default: @code{32}).
7011 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7014 @item vb/vdeblock[|difference[|flatness]]
7015 Vertical deblocking filter
7018 Difference factor where higher values mean more deblocking (default: @code{32}).
7020 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7023 @item ha/hadeblock[|difference[|flatness]]
7024 Accurate horizontal deblocking filter
7027 Difference factor where higher values mean more deblocking (default: @code{32}).
7029 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7032 @item va/vadeblock[|difference[|flatness]]
7033 Accurate vertical deblocking filter
7036 Difference factor where higher values mean more deblocking (default: @code{32}).
7038 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7042 The horizontal and vertical deblocking filters share the difference and
7043 flatness values so you cannot set different horizontal and vertical
7048 Experimental horizontal deblocking filter
7051 Experimental vertical deblocking filter
7056 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
7059 larger -> stronger filtering
7061 larger -> stronger filtering
7063 larger -> stronger filtering
7066 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
7069 Stretch luminance to @code{0-255}.
7072 @item lb/linblenddeint
7073 Linear blend deinterlacing filter that deinterlaces the given block by
7074 filtering all lines with a @code{(1 2 1)} filter.
7076 @item li/linipoldeint
7077 Linear interpolating deinterlacing filter that deinterlaces the given block by
7078 linearly interpolating every second line.
7080 @item ci/cubicipoldeint
7081 Cubic interpolating deinterlacing filter deinterlaces the given block by
7082 cubically interpolating every second line.
7084 @item md/mediandeint
7085 Median deinterlacing filter that deinterlaces the given block by applying a
7086 median filter to every second line.
7088 @item fd/ffmpegdeint
7089 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
7090 second line with a @code{(-1 4 2 4 -1)} filter.
7093 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
7094 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
7096 @item fq/forceQuant[|quantizer]
7097 Overrides the quantizer table from the input with the constant quantizer you
7105 Default pp filter combination (@code{hb|a,vb|a,dr|a})
7108 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
7111 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
7114 @subsection Examples
7118 Apply horizontal and vertical deblocking, deringing and automatic
7119 brightness/contrast:
7125 Apply default filters without brightness/contrast correction:
7131 Apply default filters and temporal denoiser:
7133 pp=default/tmpnoise|1|2|3
7137 Apply deblocking on luminance only, and switch vertical deblocking on or off
7138 automatically depending on available CPU time:
7146 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
7147 Ratio) between two input videos.
7149 This filter takes in input two input videos, the first input is
7150 considered the "main" source and is passed unchanged to the
7151 output. The second input is used as a "reference" video for computing
7154 Both video inputs must have the same resolution and pixel format for
7155 this filter to work correctly. Also it assumes that both inputs
7156 have the same number of frames, which are compared one by one.
7158 The obtained average PSNR is printed through the logging system.
7160 The filter stores the accumulated MSE (mean squared error) of each
7161 frame, and at the end of the processing it is averaged across all frames
7162 equally, and the following formula is applied to obtain the PSNR:
7165 PSNR = 10*log10(MAX^2/MSE)
7168 Where MAX is the average of the maximum values of each component of the
7171 The description of the accepted parameters follows.
7175 If specified the filter will use the named file to save the PSNR of
7176 each individual frame.
7179 The file printed if @var{stats_file} is selected, contains a sequence of
7180 key/value pairs of the form @var{key}:@var{value} for each compared
7183 A description of each shown parameter follows:
7187 sequential number of the input frame, starting from 1
7190 Mean Square Error pixel-by-pixel average difference of the compared
7191 frames, averaged over all the image components.
7193 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
7194 Mean Square Error pixel-by-pixel average difference of the compared
7195 frames for the component specified by the suffix.
7197 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
7198 Peak Signal to Noise ratio of the compared frames for the component
7199 specified by the suffix.
7204 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
7205 [main][ref] psnr="stats_file=stats.log" [out]
7208 On this example the input file being processed is compared with the
7209 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
7210 is stored in @file{stats.log}.
7215 Pulldown reversal (inverse telecine) filter, capable of handling mixed
7216 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
7219 The pullup filter is designed to take advantage of future context in making
7220 its decisions. This filter is stateless in the sense that it does not lock
7221 onto a pattern to follow, but it instead looks forward to the following
7222 fields in order to identify matches and rebuild progressive frames.
7224 To produce content with an even framerate, insert the fps filter after
7225 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
7226 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
7228 The filter accepts the following options:
7235 These options set the amount of "junk" to ignore at the left, right, top, and
7236 bottom of the image, respectively. Left and right are in units of 8 pixels,
7237 while top and bottom are in units of 2 lines.
7238 The default is 8 pixels on each side.
7241 Set the strict breaks. Setting this option to 1 will reduce the chances of
7242 filter generating an occasional mismatched frame, but it may also cause an
7243 excessive number of frames to be dropped during high motion sequences.
7244 Conversely, setting it to -1 will make filter match fields more easily.
7245 This may help processing of video where there is slight blurring between
7246 the fields, but may also cause there to be interlaced frames in the output.
7247 Default value is @code{0}.
7250 Set the metric plane to use. It accepts the following values:
7256 Use chroma blue plane.
7259 Use chroma red plane.
7262 This option may be set to use chroma plane instead of the default luma plane
7263 for doing filter's computations. This may improve accuracy on very clean
7264 source material, but more likely will decrease accuracy, especially if there
7265 is chroma noise (rainbow effect) or any grayscale video.
7266 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
7267 load and make pullup usable in realtime on slow machines.
7270 For best results (without duplicated frames in the output file) it is
7271 necessary to change the output frame rate. For example, to inverse
7272 telecine NTSC input:
7274 ffmpeg -i input -vf pullup -r 24000/1001 ...
7279 Suppress a TV station logo, using an image file to determine which
7280 pixels comprise the logo. It works by filling in the pixels that
7281 comprise the logo with neighboring pixels.
7283 The filter accepts the following options:
7287 Set the filter bitmap file, which can be any image format supported by
7288 libavformat. The width and height of the image file must match those of the
7289 video stream being processed.
7292 Pixels in the provided bitmap image with a value of zero are not
7293 considered part of the logo, non-zero pixels are considered part of
7294 the logo. If you use white (255) for the logo and black (0) for the
7295 rest, you will be safe. For making the filter bitmap, it is
7296 recommended to take a screen capture of a black frame with the logo
7297 visible, and then using a threshold filter followed by the erode
7298 filter once or twice.
7300 If needed, little splotches can be fixed manually. Remember that if
7301 logo pixels are not covered, the filter quality will be much
7302 reduced. Marking too many pixels as part of the logo does not hurt as
7303 much, but it will increase the amount of blurring needed to cover over
7304 the image and will destroy more information than necessary, and extra
7305 pixels will slow things down on a large logo.
7309 Rotate video by an arbitrary angle expressed in radians.
7311 The filter accepts the following options:
7313 A description of the optional parameters follows.
7316 Set an expression for the angle by which to rotate the input video
7317 clockwise, expressed as a number of radians. A negative value will
7318 result in a counter-clockwise rotation. By default it is set to "0".
7320 This expression is evaluated for each frame.
7323 Set the output width expression, default value is "iw".
7324 This expression is evaluated just once during configuration.
7327 Set the output height expression, default value is "ih".
7328 This expression is evaluated just once during configuration.
7331 Enable bilinear interpolation if set to 1, a value of 0 disables
7332 it. Default value is 1.
7335 Set the color used to fill the output area not covered by the rotated
7336 image. For the general syntax of this option, check the "Color" section in the
7337 ffmpeg-utils manual. If the special value "none" is selected then no
7338 background is printed (useful for example if the background is never shown).
7340 Default value is "black".
7343 The expressions for the angle and the output size can contain the
7344 following constants and functions:
7348 sequential number of the input frame, starting from 0. It is always NAN
7349 before the first frame is filtered.
7352 time in seconds of the input frame, it is set to 0 when the filter is
7353 configured. It is always NAN before the first frame is filtered.
7357 horizontal and vertical chroma subsample values. For example for the
7358 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7362 the input video width and height
7366 the output width and height, that is the size of the padded area as
7367 specified by the @var{width} and @var{height} expressions
7371 the minimal width/height required for completely containing the input
7372 video rotated by @var{a} radians.
7374 These are only available when computing the @option{out_w} and
7375 @option{out_h} expressions.
7378 @subsection Examples
7382 Rotate the input by PI/6 radians clockwise:
7388 Rotate the input by PI/6 radians counter-clockwise:
7394 Rotate the input by 45 degrees clockwise:
7400 Apply a constant rotation with period T, starting from an angle of PI/3:
7402 rotate=PI/3+2*PI*t/T
7406 Make the input video rotation oscillating with a period of T
7407 seconds and an amplitude of A radians:
7409 rotate=A*sin(2*PI/T*t)
7413 Rotate the video, output size is chosen so that the whole rotating
7414 input video is always completely contained in the output:
7416 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
7420 Rotate the video, reduce the output size so that no background is ever
7423 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
7427 @subsection Commands
7429 The filter supports the following commands:
7433 Set the angle expression.
7434 The command accepts the same syntax of the corresponding option.
7436 If the specified expression is not valid, it is kept at its current
7442 Apply Shape Adaptive Blur.
7444 The filter accepts the following options:
7447 @item luma_radius, lr
7448 Set luma blur filter strength, must be a value in range 0.1-4.0, default
7449 value is 1.0. A greater value will result in a more blurred image, and
7450 in slower processing.
7452 @item luma_pre_filter_radius, lpfr
7453 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
7456 @item luma_strength, ls
7457 Set luma maximum difference between pixels to still be considered, must
7458 be a value in the 0.1-100.0 range, default value is 1.0.
7460 @item chroma_radius, cr
7461 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
7462 greater value will result in a more blurred image, and in slower
7465 @item chroma_pre_filter_radius, cpfr
7466 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
7468 @item chroma_strength, cs
7469 Set chroma maximum difference between pixels to still be considered,
7470 must be a value in the 0.1-100.0 range.
7473 Each chroma option value, if not explicitly specified, is set to the
7474 corresponding luma option value.
7479 Scale (resize) the input video, using the libswscale library.
7481 The scale filter forces the output display aspect ratio to be the same
7482 of the input, by changing the output sample aspect ratio.
7484 If the input image format is different from the format requested by
7485 the next filter, the scale filter will convert the input to the
7489 The filter accepts the following options, or any of the options
7490 supported by the libswscale scaler.
7492 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
7493 the complete list of scaler options.
7498 Set the output video dimension expression. Default value is the input
7501 If the value is 0, the input width is used for the output.
7503 If one of the values is -1, the scale filter will use a value that
7504 maintains the aspect ratio of the input image, calculated from the
7505 other specified dimension. If both of them are -1, the input size is
7508 If one of the values is -n with n > 1, the scale filter will also use a value
7509 that maintains the aspect ratio of the input image, calculated from the other
7510 specified dimension. After that it will, however, make sure that the calculated
7511 dimension is divisible by n and adjust the value if necessary.
7513 See below for the list of accepted constants for use in the dimension
7517 Set the interlacing mode. It accepts the following values:
7521 Force interlaced aware scaling.
7524 Do not apply interlaced scaling.
7527 Select interlaced aware scaling depending on whether the source frames
7528 are flagged as interlaced or not.
7531 Default value is @samp{0}.
7534 Set libswscale scaling flags. See
7535 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7536 complete list of values. If not explicitly specified the filter applies
7540 Set the video size. For the syntax of this option, check the "Video size"
7541 section in the ffmpeg-utils manual.
7543 @item in_color_matrix
7544 @item out_color_matrix
7545 Set in/output YCbCr color space type.
7547 This allows the autodetected value to be overridden as well as allows forcing
7548 a specific value used for the output and encoder.
7550 If not specified, the color space type depends on the pixel format.
7556 Choose automatically.
7559 Format conforming to International Telecommunication Union (ITU)
7560 Recommendation BT.709.
7563 Set color space conforming to the United States Federal Communications
7564 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7567 Set color space conforming to:
7571 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7574 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7577 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7582 Set color space conforming to SMPTE ST 240:1999.
7587 Set in/output YCbCr sample range.
7589 This allows the autodetected value to be overridden as well as allows forcing
7590 a specific value used for the output and encoder. If not specified, the
7591 range depends on the pixel format. Possible values:
7595 Choose automatically.
7598 Set full range (0-255 in case of 8-bit luma).
7601 Set "MPEG" range (16-235 in case of 8-bit luma).
7604 @item force_original_aspect_ratio
7605 Enable decreasing or increasing output video width or height if necessary to
7606 keep the original aspect ratio. Possible values:
7610 Scale the video as specified and disable this feature.
7613 The output video dimensions will automatically be decreased if needed.
7616 The output video dimensions will automatically be increased if needed.
7620 One useful instance of this option is that when you know a specific device's
7621 maximum allowed resolution, you can use this to limit the output video to
7622 that, while retaining the aspect ratio. For example, device A allows
7623 1280x720 playback, and your video is 1920x800. Using this option (set it to
7624 decrease) and specifying 1280x720 to the command line makes the output
7627 Please note that this is a different thing than specifying -1 for @option{w}
7628 or @option{h}, you still need to specify the output resolution for this option
7633 The values of the @option{w} and @option{h} options are expressions
7634 containing the following constants:
7639 The input width and height
7643 These are the same as @var{in_w} and @var{in_h}.
7647 The output (scaled) width and height
7651 These are the same as @var{out_w} and @var{out_h}
7654 The same as @var{iw} / @var{ih}
7657 input sample aspect ratio
7660 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7664 horizontal and vertical input chroma subsample values. For example for the
7665 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7669 horizontal and vertical output chroma subsample values. For example for the
7670 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7673 @subsection Examples
7677 Scale the input video to a size of 200x100
7682 This is equivalent to:
7693 Specify a size abbreviation for the output size:
7698 which can also be written as:
7704 Scale the input to 2x:
7710 The above is the same as:
7716 Scale the input to 2x with forced interlaced scaling:
7718 scale=2*iw:2*ih:interl=1
7722 Scale the input to half size:
7728 Increase the width, and set the height to the same size:
7741 Increase the height, and set the width to 3/2 of the height:
7743 scale=w=3/2*oh:h=3/5*ih
7747 Increase the size, making the size a multiple of the chroma
7750 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7754 Increase the width to a maximum of 500 pixels,
7755 keeping the same aspect ratio as the input:
7757 scale=w='min(500\, iw*3/2):h=-1'
7761 @section separatefields
7763 The @code{separatefields} takes a frame-based video input and splits
7764 each frame into its components fields, producing a new half height clip
7765 with twice the frame rate and twice the frame count.
7767 This filter use field-dominance information in frame to decide which
7768 of each pair of fields to place first in the output.
7769 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7771 @section setdar, setsar
7773 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7776 This is done by changing the specified Sample (aka Pixel) Aspect
7777 Ratio, according to the following equation:
7779 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7782 Keep in mind that the @code{setdar} filter does not modify the pixel
7783 dimensions of the video frame. Also, the display aspect ratio set by
7784 this filter may be changed by later filters in the filterchain,
7785 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7788 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7789 the filter output video.
7791 Note that as a consequence of the application of this filter, the
7792 output display aspect ratio will change according to the equation
7795 Keep in mind that the sample aspect ratio set by the @code{setsar}
7796 filter may be changed by later filters in the filterchain, e.g. if
7797 another "setsar" or a "setdar" filter is applied.
7799 It accepts the following parameters:
7802 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7803 Set the aspect ratio used by the filter.
7805 The parameter can be a floating point number string, an expression, or
7806 a string of the form @var{num}:@var{den}, where @var{num} and
7807 @var{den} are the numerator and denominator of the aspect ratio. If
7808 the parameter is not specified, it is assumed the value "0".
7809 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7813 Set the maximum integer value to use for expressing numerator and
7814 denominator when reducing the expressed aspect ratio to a rational.
7815 Default value is @code{100}.
7819 The parameter @var{sar} is an expression containing
7820 the following constants:
7824 These are approximated values for the mathematical constants e
7825 (Euler's number), pi (Greek pi), and phi (the golden ratio).
7828 The input width and height.
7831 These are the same as @var{w} / @var{h}.
7834 The input sample aspect ratio.
7837 The input display aspect ratio. It is the same as
7838 (@var{w} / @var{h}) * @var{sar}.
7841 Horizontal and vertical chroma subsample values. For example, for the
7842 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7845 @subsection Examples
7850 To change the display aspect ratio to 16:9, specify one of the following:
7858 To change the sample aspect ratio to 10:11, specify:
7864 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7865 1000 in the aspect ratio reduction, use the command:
7867 setdar=ratio=16/9:max=1000
7875 Force field for the output video frame.
7877 The @code{setfield} filter marks the interlace type field for the
7878 output frames. It does not change the input frame, but only sets the
7879 corresponding property, which affects how the frame is treated by
7880 following filters (e.g. @code{fieldorder} or @code{yadif}).
7882 The filter accepts the following options:
7887 Available values are:
7891 Keep the same field property.
7894 Mark the frame as bottom-field-first.
7897 Mark the frame as top-field-first.
7900 Mark the frame as progressive.
7906 Show a line containing various information for each input video frame.
7907 The input video is not modified.
7909 The shown line contains a sequence of key/value pairs of the form
7910 @var{key}:@var{value}.
7912 The following values are shown in the output:
7916 The (sequential) number of the input frame, starting from 0.
7919 The Presentation TimeStamp of the input frame, expressed as a number of
7920 time base units. The time base unit depends on the filter input pad.
7923 The Presentation TimeStamp of the input frame, expressed as a number of
7927 The position of the frame in the input stream, or -1 if this information is
7928 unavailable and/or meaningless (for example in case of synthetic video).
7931 The pixel format name.
7934 The sample aspect ratio of the input frame, expressed in the form
7935 @var{num}/@var{den}.
7938 The size of the input frame. For the syntax of this option, check the "Video size"
7939 section in the ffmpeg-utils manual.
7942 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
7943 for bottom field first).
7946 This is 1 if the frame is a key frame, 0 otherwise.
7949 The picture type of the input frame ("I" for an I-frame, "P" for a
7950 P-frame, "B" for a B-frame, or "?" for an unknown type).
7951 Also refer to the documentation of the @code{AVPictureType} enum and of
7952 the @code{av_get_picture_type_char} function defined in
7953 @file{libavutil/avutil.h}.
7956 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
7958 @item plane_checksum
7959 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
7960 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
7963 @section shuffleplanes
7965 Reorder and/or duplicate video planes.
7967 It accepts the following parameters:
7972 The index of the input plane to be used as the first output plane.
7975 The index of the input plane to be used as the second output plane.
7978 The index of the input plane to be used as the third output plane.
7981 The index of the input plane to be used as the fourth output plane.
7985 The first plane has the index 0. The default is to keep the input unchanged.
7987 Swap the second and third planes of the input:
7989 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
7992 @section signalstats
7993 Evaluate various visual metrics that assist in determining issues associated
7994 with the digitization of analog video media.
7996 By default the filter will log these metadata values:
8000 Display the minimal Y value contained within the input frame. Expressed in
8004 Display the Y value at the 10% percentile within the input frame. Expressed in
8008 Display the average Y value within the input frame. Expressed in range of
8012 Display the Y value at the 90% percentile within the input frame. Expressed in
8016 Display the maximum Y value contained within the input frame. Expressed in
8020 Display the minimal U value contained within the input frame. Expressed in
8024 Display the U value at the 10% percentile within the input frame. Expressed in
8028 Display the average U value within the input frame. Expressed in range of
8032 Display the U value at the 90% percentile within the input frame. Expressed in
8036 Display the maximum U value contained within the input frame. Expressed in
8040 Display the minimal V value contained within the input frame. Expressed in
8044 Display the V value at the 10% percentile within the input frame. Expressed in
8048 Display the average V value within the input frame. Expressed in range of
8052 Display the V value at the 90% percentile within the input frame. Expressed in
8056 Display the maximum V value contained within the input frame. Expressed in
8060 Display the minimal saturation value contained within the input frame.
8061 Expressed in range of [0-~181.02].
8064 Display the saturation value at the 10% percentile within the input frame.
8065 Expressed in range of [0-~181.02].
8068 Display the average saturation value within the input frame. Expressed in range
8072 Display the saturation value at the 90% percentile within the input frame.
8073 Expressed in range of [0-~181.02].
8076 Display the maximum saturation value contained within the input frame.
8077 Expressed in range of [0-~181.02].
8080 Display the median value for hue within the input frame. Expressed in range of
8084 Display the average value for hue within the input frame. Expressed in range of
8088 Display the average of sample value difference between all values of the Y
8089 plane in the current frame and corresponding values of the previous input frame.
8090 Expressed in range of [0-255].
8093 Display the average of sample value difference between all values of the U
8094 plane in the current frame and corresponding values of the previous input frame.
8095 Expressed in range of [0-255].
8098 Display the average of sample value difference between all values of the V
8099 plane in the current frame and corresponding values of the previous input frame.
8100 Expressed in range of [0-255].
8103 The filter accepts the following options:
8109 @option{stat} specify an additional form of image analysis.
8110 @option{out} output video with the specified type of pixel highlighted.
8112 Both options accept the following values:
8116 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
8117 unlike the neighboring pixels of the same field. Examples of temporal outliers
8118 include the results of video dropouts, head clogs, or tape tracking issues.
8121 Identify @var{vertical line repetition}. Vertical line repetition includes
8122 similar rows of pixels within a frame. In born-digital video vertical line
8123 repetition is common, but this pattern is uncommon in video digitized from an
8124 analog source. When it occurs in video that results from the digitization of an
8125 analog source it can indicate concealment from a dropout compensator.
8128 Identify pixels that fall outside of legal broadcast range.
8132 Set the highlight color for the @option{out} option. The default color is
8136 @subsection Examples
8140 Output data of various video metrics:
8142 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
8146 Output specific data about the minimum and maximum values of the Y plane per frame:
8148 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
8152 Playback video while highlighting pixels that are outside of broadcast range in red.
8154 ffplay example.mov -vf signalstats="out=brng:color=red"
8158 Playback video with signalstats metadata drawn over the frame.
8160 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
8163 The contents of signalstat_drawtext.txt used in the command are:
8166 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
8167 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
8168 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
8169 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
8177 Blur the input video without impacting the outlines.
8179 It accepts the following options:
8182 @item luma_radius, lr
8183 Set the luma radius. The option value must be a float number in
8184 the range [0.1,5.0] that specifies the variance of the gaussian filter
8185 used to blur the image (slower if larger). Default value is 1.0.
8187 @item luma_strength, ls
8188 Set the luma strength. The option value must be a float number
8189 in the range [-1.0,1.0] that configures the blurring. A value included
8190 in [0.0,1.0] will blur the image whereas a value included in
8191 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8193 @item luma_threshold, lt
8194 Set the luma threshold used as a coefficient to determine
8195 whether a pixel should be blurred or not. The option value must be an
8196 integer in the range [-30,30]. A value of 0 will filter all the image,
8197 a value included in [0,30] will filter flat areas and a value included
8198 in [-30,0] will filter edges. Default value is 0.
8200 @item chroma_radius, cr
8201 Set the chroma radius. The option value must be a float number in
8202 the range [0.1,5.0] that specifies the variance of the gaussian filter
8203 used to blur the image (slower if larger). Default value is 1.0.
8205 @item chroma_strength, cs
8206 Set the chroma strength. The option value must be a float number
8207 in the range [-1.0,1.0] that configures the blurring. A value included
8208 in [0.0,1.0] will blur the image whereas a value included in
8209 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8211 @item chroma_threshold, ct
8212 Set the chroma threshold used as a coefficient to determine
8213 whether a pixel should be blurred or not. The option value must be an
8214 integer in the range [-30,30]. A value of 0 will filter all the image,
8215 a value included in [0,30] will filter flat areas and a value included
8216 in [-30,0] will filter edges. Default value is 0.
8219 If a chroma option is not explicitly set, the corresponding luma value
8224 Convert between different stereoscopic image formats.
8226 The filters accept the following options:
8230 Set stereoscopic image format of input.
8232 Available values for input image formats are:
8235 side by side parallel (left eye left, right eye right)
8238 side by side crosseye (right eye left, left eye right)
8241 side by side parallel with half width resolution
8242 (left eye left, right eye right)
8245 side by side crosseye with half width resolution
8246 (right eye left, left eye right)
8249 above-below (left eye above, right eye below)
8252 above-below (right eye above, left eye below)
8255 above-below with half height resolution
8256 (left eye above, right eye below)
8259 above-below with half height resolution
8260 (right eye above, left eye below)
8263 alternating frames (left eye first, right eye second)
8266 alternating frames (right eye first, left eye second)
8268 Default value is @samp{sbsl}.
8272 Set stereoscopic image format of output.
8274 Available values for output image formats are all the input formats as well as:
8277 anaglyph red/blue gray
8278 (red filter on left eye, blue filter on right eye)
8281 anaglyph red/green gray
8282 (red filter on left eye, green filter on right eye)
8285 anaglyph red/cyan gray
8286 (red filter on left eye, cyan filter on right eye)
8289 anaglyph red/cyan half colored
8290 (red filter on left eye, cyan filter on right eye)
8293 anaglyph red/cyan color
8294 (red filter on left eye, cyan filter on right eye)
8297 anaglyph red/cyan color optimized with the least squares projection of dubois
8298 (red filter on left eye, cyan filter on right eye)
8301 anaglyph green/magenta gray
8302 (green filter on left eye, magenta filter on right eye)
8305 anaglyph green/magenta half colored
8306 (green filter on left eye, magenta filter on right eye)
8309 anaglyph green/magenta colored
8310 (green filter on left eye, magenta filter on right eye)
8313 anaglyph green/magenta color optimized with the least squares projection of dubois
8314 (green filter on left eye, magenta filter on right eye)
8317 anaglyph yellow/blue gray
8318 (yellow filter on left eye, blue filter on right eye)
8321 anaglyph yellow/blue half colored
8322 (yellow filter on left eye, blue filter on right eye)
8325 anaglyph yellow/blue colored
8326 (yellow filter on left eye, blue filter on right eye)
8329 anaglyph yellow/blue color optimized with the least squares projection of dubois
8330 (yellow filter on left eye, blue filter on right eye)
8333 interleaved rows (left eye has top row, right eye starts on next row)
8336 interleaved rows (right eye has top row, left eye starts on next row)
8339 mono output (left eye only)
8342 mono output (right eye only)
8345 Default value is @samp{arcd}.
8348 @subsection Examples
8352 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
8358 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
8366 Apply a simple postprocessing filter that compresses and decompresses the image
8367 at several (or - in the case of @option{quality} level @code{6} - all) shifts
8368 and average the results.
8370 The filter accepts the following options:
8374 Set quality. This option defines the number of levels for averaging. It accepts
8375 an integer in the range 0-6. If set to @code{0}, the filter will have no
8376 effect. A value of @code{6} means the higher quality. For each increment of
8377 that value the speed drops by a factor of approximately 2. Default value is
8381 Force a constant quantization parameter. If not set, the filter will use the QP
8382 from the video stream (if available).
8385 Set thresholding mode. Available modes are:
8389 Set hard thresholding (default).
8391 Set soft thresholding (better de-ringing effect, but likely blurrier).
8395 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8396 option may cause flicker since the B-Frames have often larger QP. Default is
8397 @code{0} (not enabled).
8403 Draw subtitles on top of input video using the libass library.
8405 To enable compilation of this filter you need to configure FFmpeg with
8406 @code{--enable-libass}. This filter also requires a build with libavcodec and
8407 libavformat to convert the passed subtitles file to ASS (Advanced Substation
8408 Alpha) subtitles format.
8410 The filter accepts the following options:
8414 Set the filename of the subtitle file to read. It must be specified.
8417 Specify the size of the original video, the video for which the ASS file
8418 was composed. For the syntax of this option, check the "Video size" section in
8419 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
8420 this is necessary to correctly scale the fonts if the aspect ratio has been
8424 Set subtitles input character encoding. @code{subtitles} filter only. Only
8425 useful if not UTF-8.
8427 @item stream_index, si
8428 Set subtitles stream index. @code{subtitles} filter only.
8431 If the first key is not specified, it is assumed that the first value
8432 specifies the @option{filename}.
8434 For example, to render the file @file{sub.srt} on top of the input
8435 video, use the command:
8440 which is equivalent to:
8442 subtitles=filename=sub.srt
8445 To render the default subtitles stream from file @file{video.mkv}, use:
8450 To render the second subtitles stream from that file, use:
8452 subtitles=video.mkv:si=1
8457 Scale the input by 2x and smooth using the Super2xSaI (Scale and
8458 Interpolate) pixel art scaling algorithm.
8460 Useful for enlarging pixel art images without reducing sharpness.
8467 Apply telecine process to the video.
8469 This filter accepts the following options:
8478 The default value is @code{top}.
8482 A string of numbers representing the pulldown pattern you wish to apply.
8483 The default value is @code{23}.
8487 Some typical patterns:
8492 24p: 2332 (preferred)
8499 24p: 222222222223 ("Euro pulldown")
8505 Select the most representative frame in a given sequence of consecutive frames.
8507 The filter accepts the following options:
8511 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
8512 will pick one of them, and then handle the next batch of @var{n} frames until
8513 the end. Default is @code{100}.
8516 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
8517 value will result in a higher memory usage, so a high value is not recommended.
8519 @subsection Examples
8523 Extract one picture each 50 frames:
8529 Complete example of a thumbnail creation with @command{ffmpeg}:
8531 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
8537 Tile several successive frames together.
8539 The filter accepts the following options:
8544 Set the grid size (i.e. the number of lines and columns). For the syntax of
8545 this option, check the "Video size" section in the ffmpeg-utils manual.
8548 Set the maximum number of frames to render in the given area. It must be less
8549 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
8550 the area will be used.
8553 Set the outer border margin in pixels.
8556 Set the inner border thickness (i.e. the number of pixels between frames). For
8557 more advanced padding options (such as having different values for the edges),
8558 refer to the pad video filter.
8561 Specify the color of the unused area. For the syntax of this option, check the
8562 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
8566 @subsection Examples
8570 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
8572 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
8574 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
8575 duplicating each output frame to accommodate the originally detected frame
8579 Display @code{5} pictures in an area of @code{3x2} frames,
8580 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
8581 mixed flat and named options:
8583 tile=3x2:nb_frames=5:padding=7:margin=2
8589 Perform various types of temporal field interlacing.
8591 Frames are counted starting from 1, so the first input frame is
8594 The filter accepts the following options:
8599 Specify the mode of the interlacing. This option can also be specified
8600 as a value alone. See below for a list of values for this option.
8602 Available values are:
8606 Move odd frames into the upper field, even into the lower field,
8607 generating a double height frame at half frame rate.
8611 Frame 1 Frame 2 Frame 3 Frame 4
8613 11111 22222 33333 44444
8614 11111 22222 33333 44444
8615 11111 22222 33333 44444
8616 11111 22222 33333 44444
8630 Only output even frames, odd frames are dropped, generating a frame with
8631 unchanged height at half frame rate.
8636 Frame 1 Frame 2 Frame 3 Frame 4
8638 11111 22222 33333 44444
8639 11111 22222 33333 44444
8640 11111 22222 33333 44444
8641 11111 22222 33333 44444
8651 Only output odd frames, even frames are dropped, generating a frame with
8652 unchanged height at half frame rate.
8657 Frame 1 Frame 2 Frame 3 Frame 4
8659 11111 22222 33333 44444
8660 11111 22222 33333 44444
8661 11111 22222 33333 44444
8662 11111 22222 33333 44444
8672 Expand each frame to full height, but pad alternate lines with black,
8673 generating a frame with double height at the same input frame rate.
8678 Frame 1 Frame 2 Frame 3 Frame 4
8680 11111 22222 33333 44444
8681 11111 22222 33333 44444
8682 11111 22222 33333 44444
8683 11111 22222 33333 44444
8686 11111 ..... 33333 .....
8687 ..... 22222 ..... 44444
8688 11111 ..... 33333 .....
8689 ..... 22222 ..... 44444
8690 11111 ..... 33333 .....
8691 ..... 22222 ..... 44444
8692 11111 ..... 33333 .....
8693 ..... 22222 ..... 44444
8697 @item interleave_top, 4
8698 Interleave the upper field from odd frames with the lower field from
8699 even frames, generating a frame with unchanged height at half frame rate.
8704 Frame 1 Frame 2 Frame 3 Frame 4
8706 11111<- 22222 33333<- 44444
8707 11111 22222<- 33333 44444<-
8708 11111<- 22222 33333<- 44444
8709 11111 22222<- 33333 44444<-
8719 @item interleave_bottom, 5
8720 Interleave the lower field from odd frames with the upper field from
8721 even frames, generating a frame with unchanged height at half frame rate.
8726 Frame 1 Frame 2 Frame 3 Frame 4
8728 11111 22222<- 33333 44444<-
8729 11111<- 22222 33333<- 44444
8730 11111 22222<- 33333 44444<-
8731 11111<- 22222 33333<- 44444
8741 @item interlacex2, 6
8742 Double frame rate with unchanged height. Frames are inserted each
8743 containing the second temporal field from the previous input frame and
8744 the first temporal field from the next input frame. This mode relies on
8745 the top_field_first flag. Useful for interlaced video displays with no
8746 field synchronisation.
8751 Frame 1 Frame 2 Frame 3 Frame 4
8753 11111 22222 33333 44444
8754 11111 22222 33333 44444
8755 11111 22222 33333 44444
8756 11111 22222 33333 44444
8759 11111 22222 22222 33333 33333 44444 44444
8760 11111 11111 22222 22222 33333 33333 44444
8761 11111 22222 22222 33333 33333 44444 44444
8762 11111 11111 22222 22222 33333 33333 44444
8768 Numeric values are deprecated but are accepted for backward
8769 compatibility reasons.
8771 Default mode is @code{merge}.
8774 Specify flags influencing the filter process.
8776 Available value for @var{flags} is:
8779 @item low_pass_filter, vlfp
8780 Enable vertical low-pass filtering in the filter.
8781 Vertical low-pass filtering is required when creating an interlaced
8782 destination from a progressive source which contains high-frequency
8783 vertical detail. Filtering will reduce interlace 'twitter' and Moire
8786 Vertical low-pass filtering can only be enabled for @option{mode}
8787 @var{interleave_top} and @var{interleave_bottom}.
8794 Transpose rows with columns in the input video and optionally flip it.
8796 It accepts the following parameters:
8801 Specify the transposition direction.
8803 Can assume the following values:
8805 @item 0, 4, cclock_flip
8806 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
8814 Rotate by 90 degrees clockwise, that is:
8822 Rotate by 90 degrees counterclockwise, that is:
8829 @item 3, 7, clock_flip
8830 Rotate by 90 degrees clockwise and vertically flip, that is:
8838 For values between 4-7, the transposition is only done if the input
8839 video geometry is portrait and not landscape. These values are
8840 deprecated, the @code{passthrough} option should be used instead.
8842 Numerical values are deprecated, and should be dropped in favor of
8846 Do not apply the transposition if the input geometry matches the one
8847 specified by the specified value. It accepts the following values:
8850 Always apply transposition.
8852 Preserve portrait geometry (when @var{height} >= @var{width}).
8854 Preserve landscape geometry (when @var{width} >= @var{height}).
8857 Default value is @code{none}.
8860 For example to rotate by 90 degrees clockwise and preserve portrait
8863 transpose=dir=1:passthrough=portrait
8866 The command above can also be specified as:
8868 transpose=1:portrait
8872 Trim the input so that the output contains one continuous subpart of the input.
8874 It accepts the following parameters:
8877 Specify the time of the start of the kept section, i.e. the frame with the
8878 timestamp @var{start} will be the first frame in the output.
8881 Specify the time of the first frame that will be dropped, i.e. the frame
8882 immediately preceding the one with the timestamp @var{end} will be the last
8883 frame in the output.
8886 This is the same as @var{start}, except this option sets the start timestamp
8887 in timebase units instead of seconds.
8890 This is the same as @var{end}, except this option sets the end timestamp
8891 in timebase units instead of seconds.
8894 The maximum duration of the output in seconds.
8897 The number of the first frame that should be passed to the output.
8900 The number of the first frame that should be dropped.
8903 @option{start}, @option{end}, and @option{duration} are expressed as time
8904 duration specifications; see
8905 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
8906 for the accepted syntax.
8908 Note that the first two sets of the start/end options and the @option{duration}
8909 option look at the frame timestamp, while the _frame variants simply count the
8910 frames that pass through the filter. Also note that this filter does not modify
8911 the timestamps. If you wish for the output timestamps to start at zero, insert a
8912 setpts filter after the trim filter.
8914 If multiple start or end options are set, this filter tries to be greedy and
8915 keep all the frames that match at least one of the specified constraints. To keep
8916 only the part that matches all the constraints at once, chain multiple trim
8919 The defaults are such that all the input is kept. So it is possible to set e.g.
8920 just the end values to keep everything before the specified time.
8925 Drop everything except the second minute of input:
8927 ffmpeg -i INPUT -vf trim=60:120
8931 Keep only the first second:
8933 ffmpeg -i INPUT -vf trim=duration=1
8942 Sharpen or blur the input video.
8944 It accepts the following parameters:
8947 @item luma_msize_x, lx
8948 Set the luma matrix horizontal size. It must be an odd integer between
8949 3 and 63. The default value is 5.
8951 @item luma_msize_y, ly
8952 Set the luma matrix vertical size. It must be an odd integer between 3
8953 and 63. The default value is 5.
8955 @item luma_amount, la
8956 Set the luma effect strength. It must be a floating point number, reasonable
8957 values lay between -1.5 and 1.5.
8959 Negative values will blur the input video, while positive values will
8960 sharpen it, a value of zero will disable the effect.
8962 Default value is 1.0.
8964 @item chroma_msize_x, cx
8965 Set the chroma matrix horizontal size. It must be an odd integer
8966 between 3 and 63. The default value is 5.
8968 @item chroma_msize_y, cy
8969 Set the chroma matrix vertical size. It must be an odd integer
8970 between 3 and 63. The default value is 5.
8972 @item chroma_amount, ca
8973 Set the chroma effect strength. It must be a floating point number, reasonable
8974 values lay between -1.5 and 1.5.
8976 Negative values will blur the input video, while positive values will
8977 sharpen it, a value of zero will disable the effect.
8979 Default value is 0.0.
8982 If set to 1, specify using OpenCL capabilities, only available if
8983 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
8987 All parameters are optional and default to the equivalent of the
8988 string '5:5:1.0:5:5:0.0'.
8990 @subsection Examples
8994 Apply strong luma sharpen effect:
8996 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
9000 Apply a strong blur of both luma and chroma parameters:
9002 unsharp=7:7:-2:7:7:-2
9008 Apply ultra slow/simple postprocessing filter that compresses and decompresses
9009 the image at several (or - in the case of @option{quality} level @code{8} - all)
9010 shifts and average the results.
9012 The way this differs from the behavior of spp is that uspp actually encodes &
9013 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
9014 DCT similar to MJPEG.
9016 The filter accepts the following options:
9020 Set quality. This option defines the number of levels for averaging. It accepts
9021 an integer in the range 0-8. If set to @code{0}, the filter will have no
9022 effect. A value of @code{8} means the higher quality. For each increment of
9023 that value the speed drops by a factor of approximately 2. Default value is
9027 Force a constant quantization parameter. If not set, the filter will use the QP
9028 from the video stream (if available).
9031 @anchor{vidstabdetect}
9032 @section vidstabdetect
9034 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
9035 @ref{vidstabtransform} for pass 2.
9037 This filter generates a file with relative translation and rotation
9038 transform information about subsequent frames, which is then used by
9039 the @ref{vidstabtransform} filter.
9041 To enable compilation of this filter you need to configure FFmpeg with
9042 @code{--enable-libvidstab}.
9044 This filter accepts the following options:
9048 Set the path to the file used to write the transforms information.
9049 Default value is @file{transforms.trf}.
9052 Set how shaky the video is and how quick the camera is. It accepts an
9053 integer in the range 1-10, a value of 1 means little shakiness, a
9054 value of 10 means strong shakiness. Default value is 5.
9057 Set the accuracy of the detection process. It must be a value in the
9058 range 1-15. A value of 1 means low accuracy, a value of 15 means high
9059 accuracy. Default value is 15.
9062 Set stepsize of the search process. The region around minimum is
9063 scanned with 1 pixel resolution. Default value is 6.
9066 Set minimum contrast. Below this value a local measurement field is
9067 discarded. Must be a floating point value in the range 0-1. Default
9071 Set reference frame number for tripod mode.
9073 If enabled, the motion of the frames is compared to a reference frame
9074 in the filtered stream, identified by the specified number. The idea
9075 is to compensate all movements in a more-or-less static scene and keep
9076 the camera view absolutely still.
9078 If set to 0, it is disabled. The frames are counted starting from 1.
9081 Show fields and transforms in the resulting frames. It accepts an
9082 integer in the range 0-2. Default value is 0, which disables any
9086 @subsection Examples
9096 Analyze strongly shaky movie and put the results in file
9097 @file{mytransforms.trf}:
9099 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
9103 Visualize the result of internal transformations in the resulting
9106 vidstabdetect=show=1
9110 Analyze a video with medium shakiness using @command{ffmpeg}:
9112 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
9116 @anchor{vidstabtransform}
9117 @section vidstabtransform
9119 Video stabilization/deshaking: pass 2 of 2,
9120 see @ref{vidstabdetect} for pass 1.
9122 Read a file with transform information for each frame and
9123 apply/compensate them. Together with the @ref{vidstabdetect}
9124 filter this can be used to deshake videos. See also
9125 @url{http://public.hronopik.de/vid.stab}. It is important to also use
9126 the @ref{unsharp} filter, see below.
9128 To enable compilation of this filter you need to configure FFmpeg with
9129 @code{--enable-libvidstab}.
9135 Set path to the file used to read the transforms. Default value is
9136 @file{transforms.trf}.
9139 Set the number of frames (value*2 + 1) used for lowpass filtering the
9140 camera movements. Default value is 10.
9142 For example a number of 10 means that 21 frames are used (10 in the
9143 past and 10 in the future) to smoothen the motion in the video. A
9144 larger value leads to a smoother video, but limits the acceleration of
9145 the camera (pan/tilt movements). 0 is a special case where a static
9146 camera is simulated.
9149 Set the camera path optimization algorithm.
9151 Accepted values are:
9154 gaussian kernel low-pass filter on camera motion (default)
9156 averaging on transformations
9160 Set maximal number of pixels to translate frames. Default value is -1,
9164 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
9165 value is -1, meaning no limit.
9168 Specify how to deal with borders that may be visible due to movement
9171 Available values are:
9174 keep image information from previous frame (default)
9176 fill the border black
9180 Invert transforms if set to 1. Default value is 0.
9183 Consider transforms as relative to previous frame if set to 1,
9184 absolute if set to 0. Default value is 0.
9187 Set percentage to zoom. A positive value will result in a zoom-in
9188 effect, a negative value in a zoom-out effect. Default value is 0 (no
9192 Set optimal zooming to avoid borders.
9194 Accepted values are:
9199 optimal static zoom value is determined (only very strong movements
9200 will lead to visible borders) (default)
9202 optimal adaptive zoom value is determined (no borders will be
9203 visible), see @option{zoomspeed}
9206 Note that the value given at zoom is added to the one calculated here.
9209 Set percent to zoom maximally each frame (enabled when
9210 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
9214 Specify type of interpolation.
9216 Available values are:
9221 linear only horizontal
9223 linear in both directions (default)
9225 cubic in both directions (slow)
9229 Enable virtual tripod mode if set to 1, which is equivalent to
9230 @code{relative=0:smoothing=0}. Default value is 0.
9232 Use also @code{tripod} option of @ref{vidstabdetect}.
9235 Increase log verbosity if set to 1. Also the detected global motions
9236 are written to the temporary file @file{global_motions.trf}. Default
9240 @subsection Examples
9244 Use @command{ffmpeg} for a typical stabilization with default values:
9246 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
9249 Note the use of the @ref{unsharp} filter which is always recommended.
9252 Zoom in a bit more and load transform data from a given file:
9254 vidstabtransform=zoom=5:input="mytransforms.trf"
9258 Smoothen the video even more:
9260 vidstabtransform=smoothing=30
9266 Flip the input video vertically.
9268 For example, to vertically flip a video with @command{ffmpeg}:
9270 ffmpeg -i in.avi -vf "vflip" out.avi
9276 Make or reverse a natural vignetting effect.
9278 The filter accepts the following options:
9282 Set lens angle expression as a number of radians.
9284 The value is clipped in the @code{[0,PI/2]} range.
9286 Default value: @code{"PI/5"}
9290 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
9294 Set forward/backward mode.
9296 Available modes are:
9299 The larger the distance from the central point, the darker the image becomes.
9302 The larger the distance from the central point, the brighter the image becomes.
9303 This can be used to reverse a vignette effect, though there is no automatic
9304 detection to extract the lens @option{angle} and other settings (yet). It can
9305 also be used to create a burning effect.
9308 Default value is @samp{forward}.
9311 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
9313 It accepts the following values:
9316 Evaluate expressions only once during the filter initialization.
9319 Evaluate expressions for each incoming frame. This is way slower than the
9320 @samp{init} mode since it requires all the scalers to be re-computed, but it
9321 allows advanced dynamic expressions.
9324 Default value is @samp{init}.
9327 Set dithering to reduce the circular banding effects. Default is @code{1}
9331 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
9332 Setting this value to the SAR of the input will make a rectangular vignetting
9333 following the dimensions of the video.
9335 Default is @code{1/1}.
9338 @subsection Expressions
9340 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
9341 following parameters.
9346 input width and height
9349 the number of input frame, starting from 0
9352 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
9353 @var{TB} units, NAN if undefined
9356 frame rate of the input video, NAN if the input frame rate is unknown
9359 the PTS (Presentation TimeStamp) of the filtered video frame,
9360 expressed in seconds, NAN if undefined
9363 time base of the input video
9367 @subsection Examples
9371 Apply simple strong vignetting effect:
9377 Make a flickering vignetting:
9379 vignette='PI/4+random(1)*PI/50':eval=frame
9386 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
9387 Deinterlacing Filter").
9389 Based on the process described by Martin Weston for BBC R&D, and
9390 implemented based on the de-interlace algorithm written by Jim
9391 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
9392 uses filter coefficients calculated by BBC R&D.
9394 There are two sets of filter coefficients, so called "simple":
9395 and "complex". Which set of filter coefficients is used can
9396 be set by passing an optional parameter:
9400 Set the interlacing filter coefficients. Accepts one of the following values:
9404 Simple filter coefficient set.
9406 More-complex filter coefficient set.
9408 Default value is @samp{complex}.
9411 Specify which frames to deinterlace. Accept one of the following values:
9415 Deinterlace all frames,
9417 Only deinterlace frames marked as interlaced.
9420 Default value is @samp{all}.
9424 Apply the xBR high-quality magnification filter which is designed for pixel
9425 art. It follows a set of edge-detection rules, see
9426 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
9428 It accepts the following option:
9432 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
9433 @code{3xBR} and @code{4} for @code{4xBR}.
9434 Default is @code{3}.
9440 Deinterlace the input video ("yadif" means "yet another deinterlacing
9443 It accepts the following parameters:
9449 The interlacing mode to adopt. It accepts one of the following values:
9453 Output one frame for each frame.
9455 Output one frame for each field.
9456 @item 2, send_frame_nospatial
9457 Like @code{send_frame}, but it skips the spatial interlacing check.
9458 @item 3, send_field_nospatial
9459 Like @code{send_field}, but it skips the spatial interlacing check.
9462 The default value is @code{send_frame}.
9465 The picture field parity assumed for the input interlaced video. It accepts one
9466 of the following values:
9470 Assume the top field is first.
9472 Assume the bottom field is first.
9474 Enable automatic detection of field parity.
9477 The default value is @code{auto}.
9478 If the interlacing is unknown or the decoder does not export this information,
9479 top field first will be assumed.
9482 Specify which frames to deinterlace. Accept one of the following
9487 Deinterlace all frames.
9489 Only deinterlace frames marked as interlaced.
9492 The default value is @code{all}.
9497 Apply Zoom & Pan effect.
9499 This filter accepts the following options:
9503 Set the zoom expression. Default is 1.
9507 Set the x and y expression. Default is 0.
9510 Set the duration expression in number of frames.
9511 This sets for how many number of frames effect will last for
9515 Set the output image size, default is 'hd720'.
9518 Each expression can contain the following constants:
9541 Last calculated 'x' and 'y' position from 'x' and 'y' expression
9542 for current input frame.
9546 'x' and 'y' of last output frame of previous input frame or 0 when there was
9547 not yet such frame (first input frame).
9550 Last calculated zoom from 'z' expression for current input frame.
9553 Last calculated zoom of last output frame of previous input frame.
9556 Number of output frames for current input frame. Calculated from 'd' expression
9557 for each input frame.
9560 number of output frames created for previous input frame
9563 Rational number: input width / input height
9569 display aspect ratio
9573 @subsection Examples
9577 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
9579 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
9583 @c man end VIDEO FILTERS
9585 @chapter Video Sources
9586 @c man begin VIDEO SOURCES
9588 Below is a description of the currently available video sources.
9592 Buffer video frames, and make them available to the filter chain.
9594 This source is mainly intended for a programmatic use, in particular
9595 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
9597 It accepts the following parameters:
9602 Specify the size (width and height) of the buffered video frames. For the
9603 syntax of this option, check the "Video size" section in the ffmpeg-utils
9607 The input video width.
9610 The input video height.
9613 A string representing the pixel format of the buffered video frames.
9614 It may be a number corresponding to a pixel format, or a pixel format
9618 Specify the timebase assumed by the timestamps of the buffered frames.
9621 Specify the frame rate expected for the video stream.
9623 @item pixel_aspect, sar
9624 The sample (pixel) aspect ratio of the input video.
9627 Specify the optional parameters to be used for the scale filter which
9628 is automatically inserted when an input change is detected in the
9629 input size or format.
9634 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
9637 will instruct the source to accept video frames with size 320x240 and
9638 with format "yuv410p", assuming 1/24 as the timestamps timebase and
9639 square pixels (1:1 sample aspect ratio).
9640 Since the pixel format with name "yuv410p" corresponds to the number 6
9641 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
9642 this example corresponds to:
9644 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
9647 Alternatively, the options can be specified as a flat string, but this
9648 syntax is deprecated:
9650 @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}]
9654 Create a pattern generated by an elementary cellular automaton.
9656 The initial state of the cellular automaton can be defined through the
9657 @option{filename}, and @option{pattern} options. If such options are
9658 not specified an initial state is created randomly.
9660 At each new frame a new row in the video is filled with the result of
9661 the cellular automaton next generation. The behavior when the whole
9662 frame is filled is defined by the @option{scroll} option.
9664 This source accepts the following options:
9668 Read the initial cellular automaton state, i.e. the starting row, from
9670 In the file, each non-whitespace character is considered an alive
9671 cell, a newline will terminate the row, and further characters in the
9672 file will be ignored.
9675 Read the initial cellular automaton state, i.e. the starting row, from
9676 the specified string.
9678 Each non-whitespace character in the string is considered an alive
9679 cell, a newline will terminate the row, and further characters in the
9680 string will be ignored.
9683 Set the video rate, that is the number of frames generated per second.
9686 @item random_fill_ratio, ratio
9687 Set the random fill ratio for the initial cellular automaton row. It
9688 is a floating point number value ranging from 0 to 1, defaults to
9691 This option is ignored when a file or a pattern is specified.
9693 @item random_seed, seed
9694 Set the seed for filling randomly the initial row, must be an integer
9695 included between 0 and UINT32_MAX. If not specified, or if explicitly
9696 set to -1, the filter will try to use a good random seed on a best
9700 Set the cellular automaton rule, it is a number ranging from 0 to 255.
9701 Default value is 110.
9704 Set the size of the output video. For the syntax of this option, check
9705 the "Video size" section in the ffmpeg-utils manual.
9707 If @option{filename} or @option{pattern} is specified, the size is set
9708 by default to the width of the specified initial state row, and the
9709 height is set to @var{width} * PHI.
9711 If @option{size} is set, it must contain the width of the specified
9712 pattern string, and the specified pattern will be centered in the
9715 If a filename or a pattern string is not specified, the size value
9716 defaults to "320x518" (used for a randomly generated initial state).
9719 If set to 1, scroll the output upward when all the rows in the output
9720 have been already filled. If set to 0, the new generated row will be
9721 written over the top row just after the bottom row is filled.
9724 @item start_full, full
9725 If set to 1, completely fill the output with generated rows before
9726 outputting the first frame.
9727 This is the default behavior, for disabling set the value to 0.
9730 If set to 1, stitch the left and right row edges together.
9731 This is the default behavior, for disabling set the value to 0.
9734 @subsection Examples
9738 Read the initial state from @file{pattern}, and specify an output of
9741 cellauto=f=pattern:s=200x400
9745 Generate a random initial row with a width of 200 cells, with a fill
9748 cellauto=ratio=2/3:s=200x200
9752 Create a pattern generated by rule 18 starting by a single alive cell
9753 centered on an initial row with width 100:
9755 cellauto=p=@@:s=100x400:full=0:rule=18
9759 Specify a more elaborated initial pattern:
9761 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
9768 Generate a Mandelbrot set fractal, and progressively zoom towards the
9769 point specified with @var{start_x} and @var{start_y}.
9771 This source accepts the following options:
9776 Set the terminal pts value. Default value is 400.
9779 Set the terminal scale value.
9780 Must be a floating point value. Default value is 0.3.
9783 Set the inner coloring mode, that is the algorithm used to draw the
9784 Mandelbrot fractal internal region.
9786 It shall assume one of the following values:
9791 Show time until convergence.
9793 Set color based on point closest to the origin of the iterations.
9798 Default value is @var{mincol}.
9801 Set the bailout value. Default value is 10.0.
9804 Set the maximum of iterations performed by the rendering
9805 algorithm. Default value is 7189.
9808 Set outer coloring mode.
9809 It shall assume one of following values:
9811 @item iteration_count
9812 Set iteration cound mode.
9813 @item normalized_iteration_count
9814 set normalized iteration count mode.
9816 Default value is @var{normalized_iteration_count}.
9819 Set frame rate, expressed as number of frames per second. Default
9823 Set frame size. For the syntax of this option, check the "Video
9824 size" section in the ffmpeg-utils manual. Default value is "640x480".
9827 Set the initial scale value. Default value is 3.0.
9830 Set the initial x position. Must be a floating point value between
9831 -100 and 100. Default value is -0.743643887037158704752191506114774.
9834 Set the initial y position. Must be a floating point value between
9835 -100 and 100. Default value is -0.131825904205311970493132056385139.
9840 Generate various test patterns, as generated by the MPlayer test filter.
9842 The size of the generated video is fixed, and is 256x256.
9843 This source is useful in particular for testing encoding features.
9845 This source accepts the following options:
9850 Specify the frame rate of the sourced video, as the number of frames
9851 generated per second. It has to be a string in the format
9852 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9853 number or a valid video frame rate abbreviation. The default value is
9857 Set the duration of the sourced video. See
9858 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
9859 for the accepted syntax.
9861 If not specified, or the expressed duration is negative, the video is
9862 supposed to be generated forever.
9866 Set the number or the name of the test to perform. Supported tests are:
9882 Default value is "all", which will cycle through the list of all tests.
9890 will generate a "dc_luma" test pattern.
9894 Provide a frei0r source.
9896 To enable compilation of this filter you need to install the frei0r
9897 header and configure FFmpeg with @code{--enable-frei0r}.
9899 This source accepts the following parameters:
9904 The size of the video to generate. For the syntax of this option, check the
9905 "Video size" section in the ffmpeg-utils manual.
9908 The framerate of the generated video. It may be a string of the form
9909 @var{num}/@var{den} or a frame rate abbreviation.
9912 The name to the frei0r source to load. For more information regarding frei0r and
9913 how to set the parameters, read the @ref{frei0r} section in the video filters
9917 A '|'-separated list of parameters to pass to the frei0r source.
9921 For example, to generate a frei0r partik0l source with size 200x200
9922 and frame rate 10 which is overlaid on the overlay filter main input:
9924 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
9929 Generate a life pattern.
9931 This source is based on a generalization of John Conway's life game.
9933 The sourced input represents a life grid, each pixel represents a cell
9934 which can be in one of two possible states, alive or dead. Every cell
9935 interacts with its eight neighbours, which are the cells that are
9936 horizontally, vertically, or diagonally adjacent.
9938 At each interaction the grid evolves according to the adopted rule,
9939 which specifies the number of neighbor alive cells which will make a
9940 cell stay alive or born. The @option{rule} option allows one to specify
9943 This source accepts the following options:
9947 Set the file from which to read the initial grid state. In the file,
9948 each non-whitespace character is considered an alive cell, and newline
9949 is used to delimit the end of each row.
9951 If this option is not specified, the initial grid is generated
9955 Set the video rate, that is the number of frames generated per second.
9958 @item random_fill_ratio, ratio
9959 Set the random fill ratio for the initial random grid. It is a
9960 floating point number value ranging from 0 to 1, defaults to 1/PHI.
9961 It is ignored when a file is specified.
9963 @item random_seed, seed
9964 Set the seed for filling the initial random grid, must be an integer
9965 included between 0 and UINT32_MAX. If not specified, or if explicitly
9966 set to -1, the filter will try to use a good random seed on a best
9972 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
9973 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
9974 @var{NS} specifies the number of alive neighbor cells which make a
9975 live cell stay alive, and @var{NB} the number of alive neighbor cells
9976 which make a dead cell to become alive (i.e. to "born").
9977 "s" and "b" can be used in place of "S" and "B", respectively.
9979 Alternatively a rule can be specified by an 18-bits integer. The 9
9980 high order bits are used to encode the next cell state if it is alive
9981 for each number of neighbor alive cells, the low order bits specify
9982 the rule for "borning" new cells. Higher order bits encode for an
9983 higher number of neighbor cells.
9984 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
9985 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
9987 Default value is "S23/B3", which is the original Conway's game of life
9988 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
9989 cells, and will born a new cell if there are three alive cells around
9993 Set the size of the output video. For the syntax of this option, check the
9994 "Video size" section in the ffmpeg-utils manual.
9996 If @option{filename} is specified, the size is set by default to the
9997 same size of the input file. If @option{size} is set, it must contain
9998 the size specified in the input file, and the initial grid defined in
9999 that file is centered in the larger resulting area.
10001 If a filename is not specified, the size value defaults to "320x240"
10002 (used for a randomly generated initial grid).
10005 If set to 1, stitch the left and right grid edges together, and the
10006 top and bottom edges also. Defaults to 1.
10009 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
10010 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
10011 value from 0 to 255.
10014 Set the color of living (or new born) cells.
10017 Set the color of dead cells. If @option{mold} is set, this is the first color
10018 used to represent a dead cell.
10021 Set mold color, for definitely dead and moldy cells.
10023 For the syntax of these 3 color options, check the "Color" section in the
10024 ffmpeg-utils manual.
10027 @subsection Examples
10031 Read a grid from @file{pattern}, and center it on a grid of size
10034 life=f=pattern:s=300x300
10038 Generate a random grid of size 200x200, with a fill ratio of 2/3:
10040 life=ratio=2/3:s=200x200
10044 Specify a custom rule for evolving a randomly generated grid:
10050 Full example with slow death effect (mold) using @command{ffplay}:
10052 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
10057 @anchor{haldclutsrc}
10059 @anchor{rgbtestsrc}
10061 @anchor{smptehdbars}
10063 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
10065 The @code{color} source provides an uniformly colored input.
10067 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
10068 @ref{haldclut} filter.
10070 The @code{nullsrc} source returns unprocessed video frames. It is
10071 mainly useful to be employed in analysis / debugging tools, or as the
10072 source for filters which ignore the input data.
10074 The @code{rgbtestsrc} source generates an RGB test pattern useful for
10075 detecting RGB vs BGR issues. You should see a red, green and blue
10076 stripe from top to bottom.
10078 The @code{smptebars} source generates a color bars pattern, based on
10079 the SMPTE Engineering Guideline EG 1-1990.
10081 The @code{smptehdbars} source generates a color bars pattern, based on
10082 the SMPTE RP 219-2002.
10084 The @code{testsrc} source generates a test video pattern, showing a
10085 color pattern, a scrolling gradient and a timestamp. This is mainly
10086 intended for testing purposes.
10088 The sources accept the following parameters:
10093 Specify the color of the source, only available in the @code{color}
10094 source. For the syntax of this option, check the "Color" section in the
10095 ffmpeg-utils manual.
10098 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
10099 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
10100 pixels to be used as identity matrix for 3D lookup tables. Each component is
10101 coded on a @code{1/(N*N)} scale.
10104 Specify the size of the sourced video. For the syntax of this option, check the
10105 "Video size" section in the ffmpeg-utils manual. The default value is
10108 This option is not available with the @code{haldclutsrc} filter.
10111 Specify the frame rate of the sourced video, as the number of frames
10112 generated per second. It has to be a string in the format
10113 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
10114 number or a valid video frame rate abbreviation. The default value is
10118 Set the sample aspect ratio of the sourced video.
10121 Set the duration of the sourced video. See
10122 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
10123 for the accepted syntax.
10125 If not specified, or the expressed duration is negative, the video is
10126 supposed to be generated forever.
10129 Set the number of decimals to show in the timestamp, only available in the
10130 @code{testsrc} source.
10132 The displayed timestamp value will correspond to the original
10133 timestamp value multiplied by the power of 10 of the specified
10134 value. Default value is 0.
10137 For example the following:
10139 testsrc=duration=5.3:size=qcif:rate=10
10142 will generate a video with a duration of 5.3 seconds, with size
10143 176x144 and a frame rate of 10 frames per second.
10145 The following graph description will generate a red source
10146 with an opacity of 0.2, with size "qcif" and a frame rate of 10
10149 color=c=red@@0.2:s=qcif:r=10
10152 If the input content is to be ignored, @code{nullsrc} can be used. The
10153 following command generates noise in the luminance plane by employing
10154 the @code{geq} filter:
10156 nullsrc=s=256x256, geq=random(1)*255:128:128
10159 @subsection Commands
10161 The @code{color} source supports the following commands:
10165 Set the color of the created image. Accepts the same syntax of the
10166 corresponding @option{color} option.
10169 @c man end VIDEO SOURCES
10171 @chapter Video Sinks
10172 @c man begin VIDEO SINKS
10174 Below is a description of the currently available video sinks.
10176 @section buffersink
10178 Buffer video frames, and make them available to the end of the filter
10181 This sink is mainly intended for programmatic use, in particular
10182 through the interface defined in @file{libavfilter/buffersink.h}
10183 or the options system.
10185 It accepts a pointer to an AVBufferSinkContext structure, which
10186 defines the incoming buffers' formats, to be passed as the opaque
10187 parameter to @code{avfilter_init_filter} for initialization.
10191 Null video sink: do absolutely nothing with the input video. It is
10192 mainly useful as a template and for use in analysis / debugging
10195 @c man end VIDEO SINKS
10197 @chapter Multimedia Filters
10198 @c man begin MULTIMEDIA FILTERS
10200 Below is a description of the currently available multimedia filters.
10202 @section avectorscope
10204 Convert input audio to a video output, representing the audio vector
10207 The filter is used to measure the difference between channels of stereo
10208 audio stream. A monoaural signal, consisting of identical left and right
10209 signal, results in straight vertical line. Any stereo separation is visible
10210 as a deviation from this line, creating a Lissajous figure.
10211 If the straight (or deviation from it) but horizontal line appears this
10212 indicates that the left and right channels are out of phase.
10214 The filter accepts the following options:
10218 Set the vectorscope mode.
10220 Available values are:
10223 Lissajous rotated by 45 degrees.
10226 Same as above but not rotated.
10229 Default value is @samp{lissajous}.
10232 Set the video size for the output. For the syntax of this option, check the "Video size"
10233 section in the ffmpeg-utils manual. Default value is @code{400x400}.
10236 Set the output frame rate. Default value is @code{25}.
10241 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
10242 Allowed range is @code{[0, 255]}.
10247 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
10248 Allowed range is @code{[0, 255]}.
10251 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
10254 @subsection Examples
10258 Complete example using @command{ffplay}:
10260 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10261 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
10267 Concatenate audio and video streams, joining them together one after the
10270 The filter works on segments of synchronized video and audio streams. All
10271 segments must have the same number of streams of each type, and that will
10272 also be the number of streams at output.
10274 The filter accepts the following options:
10279 Set the number of segments. Default is 2.
10282 Set the number of output video streams, that is also the number of video
10283 streams in each segment. Default is 1.
10286 Set the number of output audio streams, that is also the number of audio
10287 streams in each segment. Default is 0.
10290 Activate unsafe mode: do not fail if segments have a different format.
10294 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
10295 @var{a} audio outputs.
10297 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
10298 segment, in the same order as the outputs, then the inputs for the second
10301 Related streams do not always have exactly the same duration, for various
10302 reasons including codec frame size or sloppy authoring. For that reason,
10303 related synchronized streams (e.g. a video and its audio track) should be
10304 concatenated at once. The concat filter will use the duration of the longest
10305 stream in each segment (except the last one), and if necessary pad shorter
10306 audio streams with silence.
10308 For this filter to work correctly, all segments must start at timestamp 0.
10310 All corresponding streams must have the same parameters in all segments; the
10311 filtering system will automatically select a common pixel format for video
10312 streams, and a common sample format, sample rate and channel layout for
10313 audio streams, but other settings, such as resolution, must be converted
10314 explicitly by the user.
10316 Different frame rates are acceptable but will result in variable frame rate
10317 at output; be sure to configure the output file to handle it.
10319 @subsection Examples
10323 Concatenate an opening, an episode and an ending, all in bilingual version
10324 (video in stream 0, audio in streams 1 and 2):
10326 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
10327 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
10328 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
10329 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
10333 Concatenate two parts, handling audio and video separately, using the
10334 (a)movie sources, and adjusting the resolution:
10336 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
10337 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
10338 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
10340 Note that a desync will happen at the stitch if the audio and video streams
10341 do not have exactly the same duration in the first file.
10347 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
10348 it unchanged. By default, it logs a message at a frequency of 10Hz with the
10349 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
10350 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
10352 The filter also has a video output (see the @var{video} option) with a real
10353 time graph to observe the loudness evolution. The graphic contains the logged
10354 message mentioned above, so it is not printed anymore when this option is set,
10355 unless the verbose logging is set. The main graphing area contains the
10356 short-term loudness (3 seconds of analysis), and the gauge on the right is for
10357 the momentary loudness (400 milliseconds).
10359 More information about the Loudness Recommendation EBU R128 on
10360 @url{http://tech.ebu.ch/loudness}.
10362 The filter accepts the following options:
10367 Activate the video output. The audio stream is passed unchanged whether this
10368 option is set or no. The video stream will be the first output stream if
10369 activated. Default is @code{0}.
10372 Set the video size. This option is for video only. For the syntax of this
10373 option, check the "Video size" section in the ffmpeg-utils manual. Default
10374 and minimum resolution is @code{640x480}.
10377 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
10378 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
10379 other integer value between this range is allowed.
10382 Set metadata injection. If set to @code{1}, the audio input will be segmented
10383 into 100ms output frames, each of them containing various loudness information
10384 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
10386 Default is @code{0}.
10389 Force the frame logging level.
10391 Available values are:
10394 information logging level
10396 verbose logging level
10399 By default, the logging level is set to @var{info}. If the @option{video} or
10400 the @option{metadata} options are set, it switches to @var{verbose}.
10405 Available modes can be cumulated (the option is a @code{flag} type). Possible
10409 Disable any peak mode (default).
10411 Enable sample-peak mode.
10413 Simple peak mode looking for the higher sample value. It logs a message
10414 for sample-peak (identified by @code{SPK}).
10416 Enable true-peak mode.
10418 If enabled, the peak lookup is done on an over-sampled version of the input
10419 stream for better peak accuracy. It logs a message for true-peak.
10420 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
10421 This mode requires a build with @code{libswresample}.
10426 @subsection Examples
10430 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
10432 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
10436 Run an analysis with @command{ffmpeg}:
10438 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
10442 @section interleave, ainterleave
10444 Temporally interleave frames from several inputs.
10446 @code{interleave} works with video inputs, @code{ainterleave} with audio.
10448 These filters read frames from several inputs and send the oldest
10449 queued frame to the output.
10451 Input streams must have a well defined, monotonically increasing frame
10454 In order to submit one frame to output, these filters need to enqueue
10455 at least one frame for each input, so they cannot work in case one
10456 input is not yet terminated and will not receive incoming frames.
10458 For example consider the case when one input is a @code{select} filter
10459 which always drop input frames. The @code{interleave} filter will keep
10460 reading from that input, but it will never be able to send new frames
10461 to output until the input will send an end-of-stream signal.
10463 Also, depending on inputs synchronization, the filters will drop
10464 frames in case one input receives more frames than the other ones, and
10465 the queue is already filled.
10467 These filters accept the following options:
10471 Set the number of different inputs, it is 2 by default.
10474 @subsection Examples
10478 Interleave frames belonging to different streams using @command{ffmpeg}:
10480 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
10484 Add flickering blur effect:
10486 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
10490 @section perms, aperms
10492 Set read/write permissions for the output frames.
10494 These filters are mainly aimed at developers to test direct path in the
10495 following filter in the filtergraph.
10497 The filters accept the following options:
10501 Select the permissions mode.
10503 It accepts the following values:
10506 Do nothing. This is the default.
10508 Set all the output frames read-only.
10510 Set all the output frames directly writable.
10512 Make the frame read-only if writable, and writable if read-only.
10514 Set each output frame read-only or writable randomly.
10518 Set the seed for the @var{random} mode, must be an integer included between
10519 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
10520 @code{-1}, the filter will try to use a good random seed on a best effort
10524 Note: in case of auto-inserted filter between the permission filter and the
10525 following one, the permission might not be received as expected in that
10526 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
10527 perms/aperms filter can avoid this problem.
10529 @section select, aselect
10531 Select frames to pass in output.
10533 This filter accepts the following options:
10538 Set expression, which is evaluated for each input frame.
10540 If the expression is evaluated to zero, the frame is discarded.
10542 If the evaluation result is negative or NaN, the frame is sent to the
10543 first output; otherwise it is sent to the output with index
10544 @code{ceil(val)-1}, assuming that the input index starts from 0.
10546 For example a value of @code{1.2} corresponds to the output with index
10547 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
10550 Set the number of outputs. The output to which to send the selected
10551 frame is based on the result of the evaluation. Default value is 1.
10554 The expression can contain the following constants:
10558 The (sequential) number of the filtered frame, starting from 0.
10561 The (sequential) number of the selected frame, starting from 0.
10563 @item prev_selected_n
10564 The sequential number of the last selected frame. It's NAN if undefined.
10567 The timebase of the input timestamps.
10570 The PTS (Presentation TimeStamp) of the filtered video frame,
10571 expressed in @var{TB} units. It's NAN if undefined.
10574 The PTS of the filtered video frame,
10575 expressed in seconds. It's NAN if undefined.
10578 The PTS of the previously filtered video frame. It's NAN if undefined.
10580 @item prev_selected_pts
10581 The PTS of the last previously filtered video frame. It's NAN if undefined.
10583 @item prev_selected_t
10584 The PTS of the last previously selected video frame. It's NAN if undefined.
10587 The PTS of the first video frame in the video. It's NAN if undefined.
10590 The time of the first video frame in the video. It's NAN if undefined.
10592 @item pict_type @emph{(video only)}
10593 The type of the filtered frame. It can assume one of the following
10605 @item interlace_type @emph{(video only)}
10606 The frame interlace type. It can assume one of the following values:
10609 The frame is progressive (not interlaced).
10611 The frame is top-field-first.
10613 The frame is bottom-field-first.
10616 @item consumed_sample_n @emph{(audio only)}
10617 the number of selected samples before the current frame
10619 @item samples_n @emph{(audio only)}
10620 the number of samples in the current frame
10622 @item sample_rate @emph{(audio only)}
10623 the input sample rate
10626 This is 1 if the filtered frame is a key-frame, 0 otherwise.
10629 the position in the file of the filtered frame, -1 if the information
10630 is not available (e.g. for synthetic video)
10632 @item scene @emph{(video only)}
10633 value between 0 and 1 to indicate a new scene; a low value reflects a low
10634 probability for the current frame to introduce a new scene, while a higher
10635 value means the current frame is more likely to be one (see the example below)
10639 The default value of the select expression is "1".
10641 @subsection Examples
10645 Select all frames in input:
10650 The example above is the same as:
10662 Select only I-frames:
10664 select='eq(pict_type\,I)'
10668 Select one frame every 100:
10670 select='not(mod(n\,100))'
10674 Select only frames contained in the 10-20 time interval:
10676 select=between(t\,10\,20)
10680 Select only I frames contained in the 10-20 time interval:
10682 select=between(t\,10\,20)*eq(pict_type\,I)
10686 Select frames with a minimum distance of 10 seconds:
10688 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
10692 Use aselect to select only audio frames with samples number > 100:
10694 aselect='gt(samples_n\,100)'
10698 Create a mosaic of the first scenes:
10700 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
10703 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
10707 Send even and odd frames to separate outputs, and compose them:
10709 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
10713 @section sendcmd, asendcmd
10715 Send commands to filters in the filtergraph.
10717 These filters read commands to be sent to other filters in the
10720 @code{sendcmd} must be inserted between two video filters,
10721 @code{asendcmd} must be inserted between two audio filters, but apart
10722 from that they act the same way.
10724 The specification of commands can be provided in the filter arguments
10725 with the @var{commands} option, or in a file specified by the
10726 @var{filename} option.
10728 These filters accept the following options:
10731 Set the commands to be read and sent to the other filters.
10733 Set the filename of the commands to be read and sent to the other
10737 @subsection Commands syntax
10739 A commands description consists of a sequence of interval
10740 specifications, comprising a list of commands to be executed when a
10741 particular event related to that interval occurs. The occurring event
10742 is typically the current frame time entering or leaving a given time
10745 An interval is specified by the following syntax:
10747 @var{START}[-@var{END}] @var{COMMANDS};
10750 The time interval is specified by the @var{START} and @var{END} times.
10751 @var{END} is optional and defaults to the maximum time.
10753 The current frame time is considered within the specified interval if
10754 it is included in the interval [@var{START}, @var{END}), that is when
10755 the time is greater or equal to @var{START} and is lesser than
10758 @var{COMMANDS} consists of a sequence of one or more command
10759 specifications, separated by ",", relating to that interval. The
10760 syntax of a command specification is given by:
10762 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
10765 @var{FLAGS} is optional and specifies the type of events relating to
10766 the time interval which enable sending the specified command, and must
10767 be a non-null sequence of identifier flags separated by "+" or "|" and
10768 enclosed between "[" and "]".
10770 The following flags are recognized:
10773 The command is sent when the current frame timestamp enters the
10774 specified interval. In other words, the command is sent when the
10775 previous frame timestamp was not in the given interval, and the
10779 The command is sent when the current frame timestamp leaves the
10780 specified interval. In other words, the command is sent when the
10781 previous frame timestamp was in the given interval, and the
10785 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
10788 @var{TARGET} specifies the target of the command, usually the name of
10789 the filter class or a specific filter instance name.
10791 @var{COMMAND} specifies the name of the command for the target filter.
10793 @var{ARG} is optional and specifies the optional list of argument for
10794 the given @var{COMMAND}.
10796 Between one interval specification and another, whitespaces, or
10797 sequences of characters starting with @code{#} until the end of line,
10798 are ignored and can be used to annotate comments.
10800 A simplified BNF description of the commands specification syntax
10803 @var{COMMAND_FLAG} ::= "enter" | "leave"
10804 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
10805 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
10806 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
10807 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
10808 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
10811 @subsection Examples
10815 Specify audio tempo change at second 4:
10817 asendcmd=c='4.0 atempo tempo 1.5',atempo
10821 Specify a list of drawtext and hue commands in a file.
10823 # show text in the interval 5-10
10824 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
10825 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
10827 # desaturate the image in the interval 15-20
10828 15.0-20.0 [enter] hue s 0,
10829 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
10831 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
10833 # apply an exponential saturation fade-out effect, starting from time 25
10834 25 [enter] hue s exp(25-t)
10837 A filtergraph allowing to read and process the above command list
10838 stored in a file @file{test.cmd}, can be specified with:
10840 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
10845 @section setpts, asetpts
10847 Change the PTS (presentation timestamp) of the input frames.
10849 @code{setpts} works on video frames, @code{asetpts} on audio frames.
10851 This filter accepts the following options:
10856 The expression which is evaluated for each frame to construct its timestamp.
10860 The expression is evaluated through the eval API and can contain the following
10865 frame rate, only defined for constant frame-rate video
10868 The presentation timestamp in input
10871 The count of the input frame for video or the number of consumed samples,
10872 not including the current frame for audio, starting from 0.
10874 @item NB_CONSUMED_SAMPLES
10875 The number of consumed samples, not including the current frame (only
10878 @item NB_SAMPLES, S
10879 The number of samples in the current frame (only audio)
10881 @item SAMPLE_RATE, SR
10882 The audio sample rate.
10885 The PTS of the first frame.
10888 the time in seconds of the first frame
10891 State whether the current frame is interlaced.
10894 the time in seconds of the current frame
10897 original position in the file of the frame, or undefined if undefined
10898 for the current frame
10901 The previous input PTS.
10904 previous input time in seconds
10907 The previous output PTS.
10910 previous output time in seconds
10913 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
10917 The wallclock (RTC) time at the start of the movie in microseconds.
10920 The timebase of the input timestamps.
10924 @subsection Examples
10928 Start counting PTS from zero
10930 setpts=PTS-STARTPTS
10934 Apply fast motion effect:
10940 Apply slow motion effect:
10946 Set fixed rate of 25 frames per second:
10952 Set fixed rate 25 fps with some jitter:
10954 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
10958 Apply an offset of 10 seconds to the input PTS:
10964 Generate timestamps from a "live source" and rebase onto the current timebase:
10966 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
10970 Generate timestamps by counting samples:
10977 @section settb, asettb
10979 Set the timebase to use for the output frames timestamps.
10980 It is mainly useful for testing timebase configuration.
10982 It accepts the following parameters:
10987 The expression which is evaluated into the output timebase.
10991 The value for @option{tb} is an arithmetic expression representing a
10992 rational. The expression can contain the constants "AVTB" (the default
10993 timebase), "intb" (the input timebase) and "sr" (the sample rate,
10994 audio only). Default value is "intb".
10996 @subsection Examples
11000 Set the timebase to 1/25:
11006 Set the timebase to 1/10:
11012 Set the timebase to 1001/1000:
11018 Set the timebase to 2*intb:
11024 Set the default timebase value:
11031 Convert input audio to a video output representing
11032 frequency spectrum logarithmically (using constant Q transform with
11033 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
11035 The filter accepts the following options:
11039 Specify transform volume (multiplier) expression. The expression can contain
11042 @item frequency, freq, f
11043 the frequency where transform is evaluated
11044 @item timeclamp, tc
11045 value of timeclamp option
11049 @item a_weighting(f)
11050 A-weighting of equal loudness
11051 @item b_weighting(f)
11052 B-weighting of equal loudness
11053 @item c_weighting(f)
11054 C-weighting of equal loudness
11056 Default value is @code{16}.
11059 Specify transform length expression. The expression can contain variables:
11061 @item frequency, freq, f
11062 the frequency where transform is evaluated
11063 @item timeclamp, tc
11064 value of timeclamp option
11066 Default value is @code{384/f*tc/(384/f+tc)}.
11069 Specify the transform timeclamp. At low frequency, there is trade-off between
11070 accuracy in time domain and frequency domain. If timeclamp is lower,
11071 event in time domain is represented more accurately (such as fast bass drum),
11072 otherwise event in frequency domain is represented more accurately
11073 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
11076 Specify the transform coeffclamp. If coeffclamp is lower, transform is
11077 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
11078 Default value is @code{1.0}.
11081 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
11082 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
11083 Default value is @code{3.0}.
11086 Specify font file for use with freetype. If not specified, use embedded font.
11089 Specify font color expression. This is arithmetic expression that should return
11090 integer value 0xRRGGBB. The expression can contain variables:
11092 @item frequency, freq, f
11093 the frequency where transform is evaluated
11094 @item timeclamp, tc
11095 value of timeclamp option
11100 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
11101 @item r(x), g(x), b(x)
11102 red, green, and blue value of intensity x
11104 Default value is @code{st(0, (midi(f)-59.5)/12);
11105 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
11106 r(1-ld(1)) + b(ld(1))}
11109 If set to 1 (the default), the video size is 1920x1080 (full HD),
11110 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
11113 Specify video fps. Default value is @code{25}.
11116 Specify number of transform per frame, so there are fps*count transforms
11117 per second. Note that audio data rate must be divisible by fps*count.
11118 Default value is @code{6}.
11122 @subsection Examples
11126 Playing audio while showing the spectrum:
11128 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
11132 Same as above, but with frame rate 30 fps:
11134 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
11138 Playing at 960x540 and lower CPU usage:
11140 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
11144 A1 and its harmonics: A1, A2, (near)E3, A3:
11146 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),
11147 asplit[a][out1]; [a] showcqt [out0]'
11151 Same as above, but with more accuracy in frequency domain (and slower):
11153 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),
11154 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
11158 B-weighting of equal loudness
11160 volume=16*b_weighting(f)
11166 tlength=100/f*tc/(100/f+tc)
11170 Custom fontcolor, C-note is colored green, others are colored blue
11172 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))'
11177 @section showspectrum
11179 Convert input audio to a video output, representing the audio frequency
11182 The filter accepts the following options:
11186 Specify the video size for the output. For the syntax of this option, check
11187 the "Video size" section in the ffmpeg-utils manual. Default value is
11191 Specify how the spectrum should slide along the window.
11193 It accepts the following values:
11196 the samples start again on the left when they reach the right
11198 the samples scroll from right to left
11200 frames are only produced when the samples reach the right
11203 Default value is @code{replace}.
11206 Specify display mode.
11208 It accepts the following values:
11211 all channels are displayed in the same row
11213 all channels are displayed in separate rows
11216 Default value is @samp{combined}.
11219 Specify display color mode.
11221 It accepts the following values:
11224 each channel is displayed in a separate color
11226 each channel is is displayed using the same color scheme
11229 Default value is @samp{channel}.
11232 Specify scale used for calculating intensity color values.
11234 It accepts the following values:
11239 square root, default
11246 Default value is @samp{sqrt}.
11249 Set saturation modifier for displayed colors. Negative values provide
11250 alternative color scheme. @code{0} is no saturation at all.
11251 Saturation must be in [-10.0, 10.0] range.
11252 Default value is @code{1}.
11255 Set window function.
11257 It accepts the following values:
11260 No samples pre-processing (do not expect this to be faster)
11269 Default value is @code{hann}.
11272 The usage is very similar to the showwaves filter; see the examples in that
11275 @subsection Examples
11279 Large window with logarithmic color scaling:
11281 showspectrum=s=1280x480:scale=log
11285 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
11287 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
11288 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
11294 Convert input audio to a video output, representing the samples waves.
11296 The filter accepts the following options:
11300 Specify the video size for the output. For the syntax of this option, check
11301 the "Video size" section in the ffmpeg-utils manual. Default value
11307 Available values are:
11310 Draw a point for each sample.
11313 Draw a vertical line for each sample.
11316 Draw a point for each sample and a line between them.
11319 Draw a centered vertical line for each sample.
11322 Default value is @code{point}.
11325 Set the number of samples which are printed on the same column. A
11326 larger value will decrease the frame rate. Must be a positive
11327 integer. This option can be set only if the value for @var{rate}
11328 is not explicitly specified.
11331 Set the (approximate) output frame rate. This is done by setting the
11332 option @var{n}. Default value is "25".
11334 @item split_channels
11335 Set if channels should be drawn separately or overlap. Default value is 0.
11339 @subsection Examples
11343 Output the input file audio and the corresponding video representation
11346 amovie=a.mp3,asplit[out0],showwaves[out1]
11350 Create a synthetic signal and show it with showwaves, forcing a
11351 frame rate of 30 frames per second:
11353 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
11357 @section split, asplit
11359 Split input into several identical outputs.
11361 @code{asplit} works with audio input, @code{split} with video.
11363 The filter accepts a single parameter which specifies the number of outputs. If
11364 unspecified, it defaults to 2.
11366 @subsection Examples
11370 Create two separate outputs from the same input:
11372 [in] split [out0][out1]
11376 To create 3 or more outputs, you need to specify the number of
11379 [in] asplit=3 [out0][out1][out2]
11383 Create two separate outputs from the same input, one cropped and
11386 [in] split [splitout1][splitout2];
11387 [splitout1] crop=100:100:0:0 [cropout];
11388 [splitout2] pad=200:200:100:100 [padout];
11392 Create 5 copies of the input audio with @command{ffmpeg}:
11394 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
11400 Receive commands sent through a libzmq client, and forward them to
11401 filters in the filtergraph.
11403 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
11404 must be inserted between two video filters, @code{azmq} between two
11407 To enable these filters you need to install the libzmq library and
11408 headers and configure FFmpeg with @code{--enable-libzmq}.
11410 For more information about libzmq see:
11411 @url{http://www.zeromq.org/}
11413 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
11414 receives messages sent through a network interface defined by the
11415 @option{bind_address} option.
11417 The received message must be in the form:
11419 @var{TARGET} @var{COMMAND} [@var{ARG}]
11422 @var{TARGET} specifies the target of the command, usually the name of
11423 the filter class or a specific filter instance name.
11425 @var{COMMAND} specifies the name of the command for the target filter.
11427 @var{ARG} is optional and specifies the optional argument list for the
11428 given @var{COMMAND}.
11430 Upon reception, the message is processed and the corresponding command
11431 is injected into the filtergraph. Depending on the result, the filter
11432 will send a reply to the client, adopting the format:
11434 @var{ERROR_CODE} @var{ERROR_REASON}
11438 @var{MESSAGE} is optional.
11440 @subsection Examples
11442 Look at @file{tools/zmqsend} for an example of a zmq client which can
11443 be used to send commands processed by these filters.
11445 Consider the following filtergraph generated by @command{ffplay}
11447 ffplay -dumpgraph 1 -f lavfi "
11448 color=s=100x100:c=red [l];
11449 color=s=100x100:c=blue [r];
11450 nullsrc=s=200x100, zmq [bg];
11451 [bg][l] overlay [bg+l];
11452 [bg+l][r] overlay=x=100 "
11455 To change the color of the left side of the video, the following
11456 command can be used:
11458 echo Parsed_color_0 c yellow | tools/zmqsend
11461 To change the right side:
11463 echo Parsed_color_1 c pink | tools/zmqsend
11466 @c man end MULTIMEDIA FILTERS
11468 @chapter Multimedia Sources
11469 @c man begin MULTIMEDIA SOURCES
11471 Below is a description of the currently available multimedia sources.
11475 This is the same as @ref{movie} source, except it selects an audio
11481 Read audio and/or video stream(s) from a movie container.
11483 It accepts the following parameters:
11487 The name of the resource to read (not necessarily a file; it can also be a
11488 device or a stream accessed through some protocol).
11490 @item format_name, f
11491 Specifies the format assumed for the movie to read, and can be either
11492 the name of a container or an input device. If not specified, the
11493 format is guessed from @var{movie_name} or by probing.
11495 @item seek_point, sp
11496 Specifies the seek point in seconds. The frames will be output
11497 starting from this seek point. The parameter is evaluated with
11498 @code{av_strtod}, so the numerical value may be suffixed by an IS
11499 postfix. The default value is "0".
11502 Specifies the streams to read. Several streams can be specified,
11503 separated by "+". The source will then have as many outputs, in the
11504 same order. The syntax is explained in the ``Stream specifiers''
11505 section in the ffmpeg manual. Two special names, "dv" and "da" specify
11506 respectively the default (best suited) video and audio stream. Default
11507 is "dv", or "da" if the filter is called as "amovie".
11509 @item stream_index, si
11510 Specifies the index of the video stream to read. If the value is -1,
11511 the most suitable video stream will be automatically selected. The default
11512 value is "-1". Deprecated. If the filter is called "amovie", it will select
11513 audio instead of video.
11516 Specifies how many times to read the stream in sequence.
11517 If the value is less than 1, the stream will be read again and again.
11518 Default value is "1".
11520 Note that when the movie is looped the source timestamps are not
11521 changed, so it will generate non monotonically increasing timestamps.
11524 It allows overlaying a second video on top of the main input of
11525 a filtergraph, as shown in this graph:
11527 input -----------> deltapts0 --> overlay --> output
11530 movie --> scale--> deltapts1 -------+
11532 @subsection Examples
11536 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
11537 on top of the input labelled "in":
11539 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
11540 [in] setpts=PTS-STARTPTS [main];
11541 [main][over] overlay=16:16 [out]
11545 Read from a video4linux2 device, and overlay it on top of the input
11548 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
11549 [in] setpts=PTS-STARTPTS [main];
11550 [main][over] overlay=16:16 [out]
11554 Read the first video stream and the audio stream with id 0x81 from
11555 dvd.vob; the video is connected to the pad named "video" and the audio is
11556 connected to the pad named "audio":
11558 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
11562 @c man end MULTIMEDIA SOURCES