1 @chapter Filtering Introduction
2 @c man begin FILTERING INTRODUCTION
4 Filtering in FFmpeg is enabled through the libavfilter library.
6 In libavfilter, a filter can have multiple inputs and multiple
8 To illustrate the sorts of things that are possible, we consider the
13 input --> split ---------------------> overlay --> output
16 +-----> crop --> vflip -------+
19 This filtergraph splits the input stream in two streams, then sends one
20 stream through the crop filter and the vflip filter, before merging it
21 back with the other stream by overlaying it on top. You can use the
22 following command to achieve this:
25 ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
28 The result will be that the top half of the video is mirrored
29 onto the bottom half of the output video.
31 Filters in the same linear chain are separated by commas, and distinct
32 linear chains of filters are separated by semicolons. In our example,
33 @var{crop,vflip} are in one linear chain, @var{split} and
34 @var{overlay} are separately in another. The points where the linear
35 chains join are labelled by names enclosed in square brackets. In the
36 example, the split filter generates two outputs that are associated to
37 the labels @var{[main]} and @var{[tmp]}.
39 The stream sent to the second output of @var{split}, labelled as
40 @var{[tmp]}, is processed through the @var{crop} filter, which crops
41 away the lower half part of the video, and then vertically flipped. The
42 @var{overlay} filter takes in input the first unchanged output of the
43 split filter (which was labelled as @var{[main]}), and overlay on its
44 lower half the output generated by the @var{crop,vflip} filterchain.
46 Some filters take in input a list of parameters: they are specified
47 after the filter name and an equal sign, and are separated from each other
50 There exist so-called @var{source filters} that do not have an
51 audio/video input, and @var{sink filters} that will not have audio/video
54 @c man end FILTERING INTRODUCTION
57 @c man begin GRAPH2DOT
59 The @file{graph2dot} program included in the FFmpeg @file{tools}
60 directory can be used to parse a filtergraph description and issue a
61 corresponding textual representation in the dot language.
68 to see how to use @file{graph2dot}.
70 You can then pass the dot description to the @file{dot} program (from
71 the graphviz suite of programs) and obtain a graphical representation
74 For example the sequence of commands:
76 echo @var{GRAPH_DESCRIPTION} | \
77 tools/graph2dot -o graph.tmp && \
78 dot -Tpng graph.tmp -o graph.png && \
82 can be used to create and display an image representing the graph
83 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
84 a complete self-contained graph, with its inputs and outputs explicitly defined.
85 For example if your command line is of the form:
87 ffmpeg -i infile -vf scale=640:360 outfile
89 your @var{GRAPH_DESCRIPTION} string will need to be of the form:
91 nullsrc,scale=640:360,nullsink
93 you may also need to set the @var{nullsrc} parameters and add a @var{format}
94 filter in order to simulate a specific input file.
98 @chapter Filtergraph description
99 @c man begin FILTERGRAPH DESCRIPTION
101 A filtergraph is a directed graph of connected filters. It can contain
102 cycles, and there can be multiple links between a pair of
103 filters. Each link has one input pad on one side connecting it to one
104 filter from which it takes its input, and one output pad on the other
105 side connecting it to one filter accepting its output.
107 Each filter in a filtergraph is an instance of a filter class
108 registered in the application, which defines the features and the
109 number of input and output pads of the filter.
111 A filter with no input pads is called a "source", and a filter with no
112 output pads is called a "sink".
114 @anchor{Filtergraph syntax}
115 @section Filtergraph syntax
117 A filtergraph has a textual representation, which is
118 recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
119 options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the
120 @code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} functions defined in
121 @file{libavfilter/avfilter.h}.
123 A filterchain consists of a sequence of connected filters, each one
124 connected to the previous one in the sequence. A filterchain is
125 represented by a list of ","-separated filter descriptions.
127 A filtergraph consists of a sequence of filterchains. A sequence of
128 filterchains is represented by a list of ";"-separated filterchain
131 A filter is represented by a string of the form:
132 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
134 @var{filter_name} is the name of the filter class of which the
135 described filter is an instance of, and has to be the name of one of
136 the filter classes registered in the program.
137 The name of the filter class is optionally followed by a string
140 @var{arguments} is a string which contains the parameters used to
141 initialize the filter instance. It may have one of two forms:
145 A ':'-separated list of @var{key=value} pairs.
148 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
149 the option names in the order they are declared. E.g. the @code{fade} filter
150 declares three options in this order -- @option{type}, @option{start_frame} and
151 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
152 @var{in} is assigned to the option @option{type}, @var{0} to
153 @option{start_frame} and @var{30} to @option{nb_frames}.
156 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
157 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
158 follow the same constraints order of the previous point. The following
159 @var{key=value} pairs can be set in any preferred order.
163 If the option value itself is a list of items (e.g. the @code{format} filter
164 takes a list of pixel formats), the items in the list are usually separated by
167 The list of arguments can be quoted using the character "'" as initial
168 and ending mark, and the character '\' for escaping the characters
169 within the quoted text; otherwise the argument string is considered
170 terminated when the next special character (belonging to the set
171 "[]=;,") is encountered.
173 The name and arguments of the filter are optionally preceded and
174 followed by a list of link labels.
175 A link label allows one to name a link and associate it to a filter output
176 or input pad. The preceding labels @var{in_link_1}
177 ... @var{in_link_N}, are associated to the filter input pads,
178 the following labels @var{out_link_1} ... @var{out_link_M}, are
179 associated to the output pads.
181 When two link labels with the same name are found in the
182 filtergraph, a link between the corresponding input and output pad is
185 If an output pad is not labelled, it is linked by default to the first
186 unlabelled input pad of the next filter in the filterchain.
187 For example in the filterchain
189 nullsrc, split[L1], [L2]overlay, nullsink
191 the split filter instance has two output pads, and the overlay filter
192 instance two input pads. The first output pad of split is labelled
193 "L1", the first input pad of overlay is labelled "L2", and the second
194 output pad of split is linked to the second input pad of overlay,
195 which are both unlabelled.
197 In a complete filterchain all the unlabelled filter input and output
198 pads must be connected. A filtergraph is considered valid if all the
199 filter input and output pads of all the filterchains are connected.
201 Libavfilter will automatically insert @ref{scale} filters where format
202 conversion is required. It is possible to specify swscale flags
203 for those automatically inserted scalers by prepending
204 @code{sws_flags=@var{flags};}
205 to the filtergraph description.
207 Here is a BNF description of the filtergraph syntax:
209 @var{NAME} ::= sequence of alphanumeric characters and '_'
210 @var{LINKLABEL} ::= "[" @var{NAME} "]"
211 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
212 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
213 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
214 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
215 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
218 @section Notes on filtergraph escaping
220 Filtergraph description composition entails several levels of
221 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
222 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
223 information about the employed escaping procedure.
225 A first level escaping affects the content of each filter option
226 value, which may contain the special character @code{:} used to
227 separate values, or one of the escaping characters @code{\'}.
229 A second level escaping affects the whole filter description, which
230 may contain the escaping characters @code{\'} or the special
231 characters @code{[],;} used by the filtergraph description.
233 Finally, when you specify a filtergraph on a shell commandline, you
234 need to perform a third level escaping for the shell special
235 characters contained within it.
237 For example, consider the following string to be embedded in
238 the @ref{drawtext} filter description @option{text} value:
240 this is a 'string': may contain one, or more, special characters
243 This string contains the @code{'} special escaping character, and the
244 @code{:} special character, so it needs to be escaped in this way:
246 text=this is a \'string\'\: may contain one, or more, special characters
249 A second level of escaping is required when embedding the filter
250 description in a filtergraph description, in order to escape all the
251 filtergraph special characters. Thus the example above becomes:
253 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
255 (note that in addition to the @code{\'} escaping special characters,
256 also @code{,} needs to be escaped).
258 Finally an additional level of escaping is needed when writing the
259 filtergraph description in a shell command, which depends on the
260 escaping rules of the adopted shell. For example, assuming that
261 @code{\} is special and needs to be escaped with another @code{\}, the
262 previous string will finally result in:
264 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
267 @chapter Timeline editing
269 Some filters support a generic @option{enable} option. For the filters
270 supporting timeline editing, this option can be set to an expression which is
271 evaluated before sending a frame to the filter. If the evaluation is non-zero,
272 the filter will be enabled, otherwise the frame will be sent unchanged to the
273 next filter in the filtergraph.
275 The expression accepts the following values:
278 timestamp expressed in seconds, NAN if the input timestamp is unknown
281 sequential number of the input frame, starting from 0
284 the position in the file of the input frame, NAN if unknown
288 width and height of the input frame if video
291 Additionally, these filters support an @option{enable} command that can be used
292 to re-define the expression.
294 Like any other filtering option, the @option{enable} option follows the same
297 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
298 minutes, and a @ref{curves} filter starting at 3 seconds:
300 smartblur = enable='between(t,10,3*60)',
301 curves = enable='gte(t,3)' : preset=cross_process
304 @c man end FILTERGRAPH DESCRIPTION
306 @chapter Audio Filters
307 @c man begin AUDIO FILTERS
309 When you configure your FFmpeg build, you can disable any of the
310 existing filters using @code{--disable-filters}.
311 The configure output will show the audio filters included in your
314 Below is a description of the currently available audio filters.
318 Delay one or more audio channels.
320 Samples in delayed channel are filled with silence.
322 The filter accepts the following option:
326 Set list of delays in milliseconds for each channel separated by '|'.
327 At least one delay greater than 0 should be provided.
328 Unused delays will be silently ignored. If number of given delays is
329 smaller than number of channels all remaining channels will not be delayed.
336 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
337 the second channel (and any other channels that may be present) unchanged.
345 Apply echoing to the input audio.
347 Echoes are reflected sound and can occur naturally amongst mountains
348 (and sometimes large buildings) when talking or shouting; digital echo
349 effects emulate this behaviour and are often used to help fill out the
350 sound of a single instrument or vocal. The time difference between the
351 original signal and the reflection is the @code{delay}, and the
352 loudness of the reflected signal is the @code{decay}.
353 Multiple echoes can have different delays and decays.
355 A description of the accepted parameters follows.
359 Set input gain of reflected signal. Default is @code{0.6}.
362 Set output gain of reflected signal. Default is @code{0.3}.
365 Set list of time intervals in milliseconds between original signal and reflections
366 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
367 Default is @code{1000}.
370 Set list of loudnesses of reflected signals separated by '|'.
371 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
372 Default is @code{0.5}.
379 Make it sound as if there are twice as many instruments as are actually playing:
381 aecho=0.8:0.88:60:0.4
385 If delay is very short, then it sound like a (metallic) robot playing music:
391 A longer delay will sound like an open air concert in the mountains:
393 aecho=0.8:0.9:1000:0.3
397 Same as above but with one more mountain:
399 aecho=0.8:0.9:1000|1800:0.3|0.25
405 Modify an audio signal according to the specified expressions.
407 This filter accepts one or more expressions (one for each channel),
408 which are evaluated and used to modify a corresponding audio signal.
410 It accepts the following parameters:
414 Set the '|'-separated expressions list for each separate channel. If
415 the number of input channels is greater than the number of
416 expressions, the last specified expression is used for the remaining
419 @item channel_layout, c
420 Set output channel layout. If not specified, the channel layout is
421 specified by the number of expressions. If set to @samp{same}, it will
422 use by default the same input channel layout.
425 Each expression in @var{exprs} can contain the following constants and functions:
429 channel number of the current expression
432 number of the evaluated sample, starting from 0
438 time of the evaluated sample expressed in seconds
441 @item nb_out_channels
442 input and output number of channels
445 the value of input channel with number @var{CH}
448 Note: this filter is slow. For faster processing you should use a
457 aeval=val(ch)/2:c=same
461 Invert phase of the second channel:
469 Apply fade-in/out effect to input audio.
471 A description of the accepted parameters follows.
475 Specify the effect type, can be either @code{in} for fade-in, or
476 @code{out} for a fade-out effect. Default is @code{in}.
478 @item start_sample, ss
479 Specify the number of the start sample for starting to apply the fade
480 effect. Default is 0.
483 Specify the number of samples for which the fade effect has to last. At
484 the end of the fade-in effect the output audio will have the same
485 volume as the input audio, at the end of the fade-out transition
486 the output audio will be silence. Default is 44100.
489 Specify the start time of the fade effect. Default is 0.
490 The value must be specified as a time duration; see
491 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
492 for the accepted syntax.
493 If set this option is used instead of @var{start_sample}.
496 Specify the duration of the fade effect. See
497 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
498 for the accepted syntax.
499 At the end of the fade-in effect the output audio will have the same
500 volume as the input audio, at the end of the fade-out transition
501 the output audio will be silence.
502 By default the duration is determined by @var{nb_samples}.
503 If set this option is used instead of @var{nb_samples}.
506 Set curve for fade transition.
508 It accepts the following values:
511 select triangular, linear slope (default)
513 select quarter of sine wave
515 select half of sine wave
517 select exponential sine wave
521 select inverted parabola
537 Fade in first 15 seconds of audio:
543 Fade out last 25 seconds of a 900 seconds audio:
545 afade=t=out:st=875:d=25
552 Set output format constraints for the input audio. The framework will
553 negotiate the most appropriate format to minimize conversions.
555 It accepts the following parameters:
559 A '|'-separated list of requested sample formats.
562 A '|'-separated list of requested sample rates.
564 @item channel_layouts
565 A '|'-separated list of requested channel layouts.
567 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
568 for the required syntax.
571 If a parameter is omitted, all values are allowed.
573 Force the output to either unsigned 8-bit or signed 16-bit stereo
575 aformat=sample_fmts=u8|s16:channel_layouts=stereo
580 Apply a two-pole all-pass filter with central frequency (in Hz)
581 @var{frequency}, and filter-width @var{width}.
582 An all-pass filter changes the audio's frequency to phase relationship
583 without changing its frequency to amplitude relationship.
585 The filter accepts the following options:
592 Set method to specify band-width of filter.
605 Specify the band-width of a filter in width_type units.
610 Merge two or more audio streams into a single multi-channel stream.
612 The filter accepts the following options:
617 Set the number of inputs. Default is 2.
621 If the channel layouts of the inputs are disjoint, and therefore compatible,
622 the channel layout of the output will be set accordingly and the channels
623 will be reordered as necessary. If the channel layouts of the inputs are not
624 disjoint, the output will have all the channels of the first input then all
625 the channels of the second input, in that order, and the channel layout of
626 the output will be the default value corresponding to the total number of
629 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
630 is FC+BL+BR, then the output will be in 5.1, with the channels in the
631 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
632 first input, b1 is the first channel of the second input).
634 On the other hand, if both input are in stereo, the output channels will be
635 in the default order: a1, a2, b1, b2, and the channel layout will be
636 arbitrarily set to 4.0, which may or may not be the expected value.
638 All inputs must have the same sample rate, and format.
640 If inputs do not have the same duration, the output will stop with the
647 Merge two mono files into a stereo stream:
649 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
653 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
655 ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv
661 Mixes multiple audio inputs into a single output.
663 Note that this filter only supports float samples (the @var{amerge}
664 and @var{pan} audio filters support many formats). If the @var{amix}
665 input has integer samples then @ref{aresample} will be automatically
666 inserted to perform the conversion to float samples.
670 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
672 will mix 3 input audio streams to a single output with the same duration as the
673 first input and a dropout transition time of 3 seconds.
675 It accepts the following parameters:
679 The number of inputs. If unspecified, it defaults to 2.
682 How to determine the end-of-stream.
686 The duration of the longest input. (default)
689 The duration of the shortest input.
692 The duration of the first input.
696 @item dropout_transition
697 The transition time, in seconds, for volume renormalization when an input
698 stream ends. The default value is 2 seconds.
704 Pass the audio source unchanged to the output.
708 Pad the end of an audio stream with silence.
710 This can be used together with @command{ffmpeg} @option{-shortest} to
711 extend audio streams to the same length as the video stream.
713 A description of the accepted options follows.
717 Set silence packet size. Default value is 4096.
720 Set the number of samples of silence to add to the end. After the
721 value is reached, the stream is terminated. This option is mutually
722 exclusive with @option{whole_len}.
725 Set the minimum total number of samples in the output audio stream. If
726 the value is longer than the input audio length, silence is added to
727 the end, until the value is reached. This option is mutually exclusive
728 with @option{pad_len}.
731 If neither the @option{pad_len} nor the @option{whole_len} option is
732 set, the filter will add silence to the end of the input stream
739 Add 1024 samples of silence to the end of the input:
745 Make sure the audio output will contain at least 10000 samples, pad
746 the input with silence if required:
752 Use @command{ffmpeg} to pad the audio input with silence, so that the
753 video stream will always result the shortest and will be converted
754 until the end in the output file when using the @option{shortest}
757 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
762 Add a phasing effect to the input audio.
764 A phaser filter creates series of peaks and troughs in the frequency spectrum.
765 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
767 A description of the accepted parameters follows.
771 Set input gain. Default is 0.4.
774 Set output gain. Default is 0.74
777 Set delay in milliseconds. Default is 3.0.
780 Set decay. Default is 0.4.
783 Set modulation speed in Hz. Default is 0.5.
786 Set modulation type. Default is triangular.
788 It accepts the following values:
798 Resample the input audio to the specified parameters, using the
799 libswresample library. If none are specified then the filter will
800 automatically convert between its input and output.
802 This filter is also able to stretch/squeeze the audio data to make it match
803 the timestamps or to inject silence / cut out audio to make it match the
804 timestamps, do a combination of both or do neither.
806 The filter accepts the syntax
807 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
808 expresses a sample rate and @var{resampler_options} is a list of
809 @var{key}=@var{value} pairs, separated by ":". See the
810 ffmpeg-resampler manual for the complete list of supported options.
816 Resample the input audio to 44100Hz:
822 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
823 samples per second compensation:
829 @section asetnsamples
831 Set the number of samples per each output audio frame.
833 The last output packet may contain a different number of samples, as
834 the filter will flush all the remaining samples when the input audio
837 The filter accepts the following options:
841 @item nb_out_samples, n
842 Set the number of frames per each output audio frame. The number is
843 intended as the number of samples @emph{per each channel}.
844 Default value is 1024.
847 If set to 1, the filter will pad the last audio frame with zeroes, so
848 that the last frame will contain the same number of samples as the
849 previous ones. Default value is 1.
852 For example, to set the number of per-frame samples to 1234 and
853 disable padding for the last frame, use:
855 asetnsamples=n=1234:p=0
860 Set the sample rate without altering the PCM data.
861 This will result in a change of speed and pitch.
863 The filter accepts the following options:
867 Set the output sample rate. Default is 44100 Hz.
872 Show a line containing various information for each input audio frame.
873 The input audio is not modified.
875 The shown line contains a sequence of key/value pairs of the form
876 @var{key}:@var{value}.
878 The following values are shown in the output:
882 The (sequential) number of the input frame, starting from 0.
885 The presentation timestamp of the input frame, in time base units; the time base
886 depends on the filter input pad, and is usually 1/@var{sample_rate}.
889 The presentation timestamp of the input frame in seconds.
892 position of the frame in the input stream, -1 if this information in
893 unavailable and/or meaningless (for example in case of synthetic audio)
902 The sample rate for the audio frame.
905 The number of samples (per channel) in the frame.
908 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
909 audio, the data is treated as if all the planes were concatenated.
911 @item plane_checksums
912 A list of Adler-32 checksums for each data plane.
917 Display time domain statistical information about the audio channels.
918 Statistics are calculated and displayed for each audio channel and,
919 where applicable, an overall figure is also given.
921 It accepts the following option:
924 Short window length in seconds, used for peak and trough RMS measurement.
925 Default is @code{0.05} (50 milliseconds). Allowed range is @code{[0.1 - 10]}.
928 A description of each shown parameter follows:
932 Mean amplitude displacement from zero.
935 Minimal sample level.
938 Maximal sample level.
942 Standard peak and RMS level measured in dBFS.
946 Peak and trough values for RMS level measured over a short window.
949 Standard ratio of peak to RMS level (note: not in dB).
952 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
953 (i.e. either @var{Min level} or @var{Max level}).
956 Number of occasions (not the number of samples) that the signal attained either
957 @var{Min level} or @var{Max level}.
962 Forward two audio streams and control the order the buffers are forwarded.
964 The filter accepts the following options:
968 Set the expression deciding which stream should be
969 forwarded next: if the result is negative, the first stream is forwarded; if
970 the result is positive or zero, the second stream is forwarded. It can use
971 the following variables:
975 number of buffers forwarded so far on each stream
977 number of samples forwarded so far on each stream
979 current timestamp of each stream
982 The default value is @code{t1-t2}, which means to always forward the stream
983 that has a smaller timestamp.
988 Stress-test @code{amerge} by randomly sending buffers on the wrong
989 input, while avoiding too much of a desynchronization:
991 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
992 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
998 Synchronize audio data with timestamps by squeezing/stretching it and/or
999 dropping samples/adding silence when needed.
1001 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1003 It accepts the following parameters:
1007 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1008 by default. When disabled, time gaps are covered with silence.
1011 The minimum difference between timestamps and audio data (in seconds) to trigger
1012 adding/dropping samples. The default value is 0.1. If you get an imperfect
1013 sync with this filter, try setting this parameter to 0.
1016 The maximum compensation in samples per second. Only relevant with compensate=1.
1017 The default value is 500.
1020 Assume that the first PTS should be this value. The time base is 1 / sample
1021 rate. This allows for padding/trimming at the start of the stream. By default,
1022 no assumption is made about the first frame's expected PTS, so no padding or
1023 trimming is done. For example, this could be set to 0 to pad the beginning with
1024 silence if an audio stream starts after the video stream or to trim any samples
1025 with a negative PTS due to encoder delay.
1033 The filter accepts exactly one parameter, the audio tempo. If not
1034 specified then the filter will assume nominal 1.0 tempo. Tempo must
1035 be in the [0.5, 2.0] range.
1037 @subsection Examples
1041 Slow down audio to 80% tempo:
1047 To speed up audio to 125% tempo:
1055 Trim the input so that the output contains one continuous subpart of the input.
1057 It accepts the following parameters:
1060 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1061 sample with the timestamp @var{start} will be the first sample in the output.
1064 Specify time of the first audio sample that will be dropped, i.e. the
1065 audio sample immediately preceding the one with the timestamp @var{end} will be
1066 the last sample in the output.
1069 Same as @var{start}, except this option sets the start timestamp in samples
1073 Same as @var{end}, except this option sets the end timestamp in samples instead
1077 The maximum duration of the output in seconds.
1080 The number of the first sample that should be output.
1083 The number of the first sample that should be dropped.
1086 @option{start}, @option{end}, and @option{duration} are expressed as time
1087 duration specifications; see
1088 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
1090 Note that the first two sets of the start/end options and the @option{duration}
1091 option look at the frame timestamp, while the _sample options simply count the
1092 samples that pass through the filter. So start/end_pts and start/end_sample will
1093 give different results when the timestamps are wrong, inexact or do not start at
1094 zero. Also note that this filter does not modify the timestamps. If you wish
1095 to have the output timestamps start at zero, insert the asetpts filter after the
1098 If multiple start or end options are set, this filter tries to be greedy and
1099 keep all samples that match at least one of the specified constraints. To keep
1100 only the part that matches all the constraints at once, chain multiple atrim
1103 The defaults are such that all the input is kept. So it is possible to set e.g.
1104 just the end values to keep everything before the specified time.
1109 Drop everything except the second minute of input:
1111 ffmpeg -i INPUT -af atrim=60:120
1115 Keep only the first 1000 samples:
1117 ffmpeg -i INPUT -af atrim=end_sample=1000
1124 Apply a two-pole Butterworth band-pass filter with central
1125 frequency @var{frequency}, and (3dB-point) band-width width.
1126 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1127 instead of the default: constant 0dB peak gain.
1128 The filter roll off at 6dB per octave (20dB per decade).
1130 The filter accepts the following options:
1134 Set the filter's central frequency. Default is @code{3000}.
1137 Constant skirt gain if set to 1. Defaults to 0.
1140 Set method to specify band-width of filter.
1153 Specify the band-width of a filter in width_type units.
1158 Apply a two-pole Butterworth band-reject filter with central
1159 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1160 The filter roll off at 6dB per octave (20dB per decade).
1162 The filter accepts the following options:
1166 Set the filter's central frequency. Default is @code{3000}.
1169 Set method to specify band-width of filter.
1182 Specify the band-width of a filter in width_type units.
1187 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1188 shelving filter with a response similar to that of a standard
1189 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1191 The filter accepts the following options:
1195 Give the gain at 0 Hz. Its useful range is about -20
1196 (for a large cut) to +20 (for a large boost).
1197 Beware of clipping when using a positive gain.
1200 Set the filter's central frequency and so can be used
1201 to extend or reduce the frequency range to be boosted or cut.
1202 The default value is @code{100} Hz.
1205 Set method to specify band-width of filter.
1218 Determine how steep is the filter's shelf transition.
1223 Apply a biquad IIR filter with the given coefficients.
1224 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1225 are the numerator and denominator coefficients respectively.
1228 Bauer stereo to binaural transformation, which improves headphone listening of
1229 stereo audio records.
1231 It accepts the following parameters:
1235 Pre-defined crossfeed level.
1239 Default level (fcut=700, feed=50).
1242 Chu Moy circuit (fcut=700, feed=60).
1245 Jan Meier circuit (fcut=650, feed=95).
1250 Cut frequency (in Hz).
1259 Remap input channels to new locations.
1261 It accepts the following parameters:
1263 @item channel_layout
1264 The channel layout of the output stream.
1267 Map channels from input to output. The argument is a '|'-separated list of
1268 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1269 @var{in_channel} form. @var{in_channel} can be either the name of the input
1270 channel (e.g. FL for front left) or its index in the input channel layout.
1271 @var{out_channel} is the name of the output channel or its index in the output
1272 channel layout. If @var{out_channel} is not given then it is implicitly an
1273 index, starting with zero and increasing by one for each mapping.
1276 If no mapping is present, the filter will implicitly map input channels to
1277 output channels, preserving indices.
1279 For example, assuming a 5.1+downmix input MOV file,
1281 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1283 will create an output WAV file tagged as stereo from the downmix channels of
1286 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1288 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1291 @section channelsplit
1293 Split each channel from an input audio stream into a separate output stream.
1295 It accepts the following parameters:
1297 @item channel_layout
1298 The channel layout of the input stream. The default is "stereo".
1301 For example, assuming a stereo input MP3 file,
1303 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1305 will create an output Matroska file with two audio streams, one containing only
1306 the left channel and the other the right channel.
1308 Split a 5.1 WAV file into per-channel files:
1310 ffmpeg -i in.wav -filter_complex
1311 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1312 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1313 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1318 Compress or expand the audio's dynamic range.
1320 It accepts the following parameters:
1326 A list of times in seconds for each channel over which the instantaneous level
1327 of the input signal is averaged to determine its volume. @var{attacks} refers to
1328 increase of volume and @var{decays} refers to decrease of volume. For most
1329 situations, the attack time (response to the audio getting louder) should be
1330 shorter than the decay time, because the human ear is more sensitive to sudden
1331 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1332 a typical value for decay is 0.8 seconds.
1335 A list of points for the transfer function, specified in dB relative to the
1336 maximum possible signal amplitude. Each key points list must be defined using
1337 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1338 @code{x0/y0 x1/y1 x2/y2 ....}
1340 The input values must be in strictly increasing order but the transfer function
1341 does not have to be monotonically rising. The point @code{0/0} is assumed but
1342 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1343 function are @code{-70/-70|-60/-20}.
1346 Set the curve radius in dB for all joints. It defaults to 0.01.
1349 Set the additional gain in dB to be applied at all points on the transfer
1350 function. This allows for easy adjustment of the overall gain.
1354 Set an initial volume, in dB, to be assumed for each channel when filtering
1355 starts. This permits the user to supply a nominal level initially, so that, for
1356 example, a very large gain is not applied to initial signal levels before the
1357 companding has begun to operate. A typical value for audio which is initially
1358 quiet is -90 dB. It defaults to 0.
1361 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1362 delayed before being fed to the volume adjuster. Specifying a delay
1363 approximately equal to the attack/decay times allows the filter to effectively
1364 operate in predictive rather than reactive mode. It defaults to 0.
1368 @subsection Examples
1372 Make music with both quiet and loud passages suitable for listening to in a
1375 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1379 A noise gate for when the noise is at a lower level than the signal:
1381 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1385 Here is another noise gate, this time for when the noise is at a higher level
1386 than the signal (making it, in some ways, similar to squelch):
1388 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1394 Make audio easier to listen to on headphones.
1396 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1397 so that when listened to on headphones the stereo image is moved from
1398 inside your head (standard for headphones) to outside and in front of
1399 the listener (standard for speakers).
1405 Apply a two-pole peaking equalisation (EQ) filter. With this
1406 filter, the signal-level at and around a selected frequency can
1407 be increased or decreased, whilst (unlike bandpass and bandreject
1408 filters) that at all other frequencies is unchanged.
1410 In order to produce complex equalisation curves, this filter can
1411 be given several times, each with a different central frequency.
1413 The filter accepts the following options:
1417 Set the filter's central frequency in Hz.
1420 Set method to specify band-width of filter.
1433 Specify the band-width of a filter in width_type units.
1436 Set the required gain or attenuation in dB.
1437 Beware of clipping when using a positive gain.
1440 @subsection Examples
1443 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1445 equalizer=f=1000:width_type=h:width=200:g=-10
1449 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1451 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1456 Apply a flanging effect to the audio.
1458 The filter accepts the following options:
1462 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
1465 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
1468 Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
1472 Set percentage of delayed signal mixed with original. Range from 0 to 100.
1473 Default value is 71.
1476 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
1479 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
1480 Default value is @var{sinusoidal}.
1483 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
1484 Default value is 25.
1487 Set delay-line interpolation, @var{linear} or @var{quadratic}.
1488 Default is @var{linear}.
1493 Apply a high-pass filter with 3dB point frequency.
1494 The filter can be either single-pole, or double-pole (the default).
1495 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1497 The filter accepts the following options:
1501 Set frequency in Hz. Default is 3000.
1504 Set number of poles. Default is 2.
1507 Set method to specify band-width of filter.
1520 Specify the band-width of a filter in width_type units.
1521 Applies only to double-pole filter.
1522 The default is 0.707q and gives a Butterworth response.
1527 Join multiple input streams into one multi-channel stream.
1529 It accepts the following parameters:
1533 The number of input streams. It defaults to 2.
1535 @item channel_layout
1536 The desired output channel layout. It defaults to stereo.
1539 Map channels from inputs to output. The argument is a '|'-separated list of
1540 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1541 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1542 can be either the name of the input channel (e.g. FL for front left) or its
1543 index in the specified input stream. @var{out_channel} is the name of the output
1547 The filter will attempt to guess the mappings when they are not specified
1548 explicitly. It does so by first trying to find an unused matching input channel
1549 and if that fails it picks the first unused input channel.
1551 Join 3 inputs (with properly set channel layouts):
1553 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1556 Build a 5.1 output from 6 single-channel streams:
1558 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1559 'join=inputs=6:channel_layout=5.1:map=0.0-FL|1.0-FR|2.0-FC|3.0-SL|4.0-SR|5.0-LFE'
1565 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1567 To enable compilation of this filter you need to configure FFmpeg with
1568 @code{--enable-ladspa}.
1572 Specifies the name of LADSPA plugin library to load. If the environment
1573 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1574 each one of the directories specified by the colon separated list in
1575 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1576 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1577 @file{/usr/lib/ladspa/}.
1580 Specifies the plugin within the library. Some libraries contain only
1581 one plugin, but others contain many of them. If this is not set filter
1582 will list all available plugins within the specified library.
1585 Set the '|' separated list of controls which are zero or more floating point
1586 values that determine the behavior of the loaded plugin (for example delay,
1588 Controls need to be defined using the following syntax:
1589 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1590 @var{valuei} is the value set on the @var{i}-th control.
1591 If @option{controls} is set to @code{help}, all available controls and
1592 their valid ranges are printed.
1594 @item sample_rate, s
1595 Specify the sample rate, default to 44100. Only used if plugin have
1599 Set the number of samples per channel per each output frame, default
1600 is 1024. Only used if plugin have zero inputs.
1603 Set the minimum duration of the sourced audio. See
1604 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
1605 for the accepted syntax.
1606 Note that the resulting duration may be greater than the specified duration,
1607 as the generated audio is always cut at the end of a complete frame.
1608 If not specified, or the expressed duration is negative, the audio is
1609 supposed to be generated forever.
1610 Only used if plugin have zero inputs.
1614 @subsection Examples
1618 List all available plugins within amp (LADSPA example plugin) library:
1624 List all available controls and their valid ranges for @code{vcf_notch}
1625 plugin from @code{VCF} library:
1627 ladspa=f=vcf:p=vcf_notch:c=help
1631 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1634 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1638 Add reverberation to the audio using TAP-plugins
1639 (Tom's Audio Processing plugins):
1641 ladspa=file=tap_reverb:tap_reverb
1645 Generate white noise, with 0.2 amplitude:
1647 ladspa=file=cmt:noise_source_white:c=c0=.2
1651 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1652 @code{C* Audio Plugin Suite} (CAPS) library:
1654 ladspa=file=caps:Click:c=c1=20'
1658 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1660 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1664 @subsection Commands
1666 This filter supports the following commands:
1669 Modify the @var{N}-th control value.
1671 If the specified value is not valid, it is ignored and prior one is kept.
1676 Apply a low-pass filter with 3dB point frequency.
1677 The filter can be either single-pole or double-pole (the default).
1678 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1680 The filter accepts the following options:
1684 Set frequency in Hz. Default is 500.
1687 Set number of poles. Default is 2.
1690 Set method to specify band-width of filter.
1703 Specify the band-width of a filter in width_type units.
1704 Applies only to double-pole filter.
1705 The default is 0.707q and gives a Butterworth response.
1710 Mix channels with specific gain levels. The filter accepts the output
1711 channel layout followed by a set of channels definitions.
1713 This filter is also designed to efficiently remap the channels of an audio
1716 The filter accepts parameters of the form:
1717 "@var{l}|@var{outdef}|@var{outdef}|..."
1721 output channel layout or number of channels
1724 output channel specification, of the form:
1725 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1728 output channel to define, either a channel name (FL, FR, etc.) or a channel
1729 number (c0, c1, etc.)
1732 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1735 input channel to use, see out_name for details; it is not possible to mix
1736 named and numbered input channels
1739 If the `=' in a channel specification is replaced by `<', then the gains for
1740 that specification will be renormalized so that the total is 1, thus
1741 avoiding clipping noise.
1743 @subsection Mixing examples
1745 For example, if you want to down-mix from stereo to mono, but with a bigger
1746 factor for the left channel:
1748 pan=1c|c0=0.9*c0+0.1*c1
1751 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1752 7-channels surround:
1754 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1757 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1758 that should be preferred (see "-ac" option) unless you have very specific
1761 @subsection Remapping examples
1763 The channel remapping will be effective if, and only if:
1766 @item gain coefficients are zeroes or ones,
1767 @item only one input per channel output,
1770 If all these conditions are satisfied, the filter will notify the user ("Pure
1771 channel mapping detected"), and use an optimized and lossless method to do the
1774 For example, if you have a 5.1 source and want a stereo audio stream by
1775 dropping the extra channels:
1777 pan="stereo| c0=FL | c1=FR"
1780 Given the same source, you can also switch front left and front right channels
1781 and keep the input channel layout:
1783 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
1786 If the input is a stereo audio stream, you can mute the front left channel (and
1787 still keep the stereo channel layout) with:
1792 Still with a stereo audio stream input, you can copy the right channel in both
1793 front left and right:
1795 pan="stereo| c0=FR | c1=FR"
1800 ReplayGain scanner filter. This filter takes an audio stream as an input and
1801 outputs it unchanged.
1802 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1806 Convert the audio sample format, sample rate and channel layout. It is
1807 not meant to be used directly.
1809 @section silencedetect
1811 Detect silence in an audio stream.
1813 This filter logs a message when it detects that the input audio volume is less
1814 or equal to a noise tolerance value for a duration greater or equal to the
1815 minimum detected noise duration.
1817 The printed times and duration are expressed in seconds.
1819 The filter accepts the following options:
1823 Set silence duration until notification (default is 2 seconds).
1826 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1827 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1830 @subsection Examples
1834 Detect 5 seconds of silence with -50dB noise tolerance:
1836 silencedetect=n=-50dB:d=5
1840 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1841 tolerance in @file{silence.mp3}:
1843 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1847 @section silenceremove
1849 Remove silence from the beginning, middle or end of the audio.
1851 The filter accepts the following options:
1855 This value is used to indicate if audio should be trimmed at beginning of
1856 the audio. A value of zero indicates no silence should be trimmed from the
1857 beginning. When specifying a non-zero value, it trims audio up until it
1858 finds non-silence. Normally, when trimming silence from beginning of audio
1859 the @var{start_periods} will be @code{1} but it can be increased to higher
1860 values to trim all audio up to specific count of non-silence periods.
1861 Default value is @code{0}.
1863 @item start_duration
1864 Specify the amount of time that non-silence must be detected before it stops
1865 trimming audio. By increasing the duration, bursts of noises can be treated
1866 as silence and trimmed off. Default value is @code{0}.
1868 @item start_threshold
1869 This indicates what sample value should be treated as silence. For digital
1870 audio, a value of @code{0} may be fine but for audio recorded from analog,
1871 you may wish to increase the value to account for background noise.
1872 Can be specified in dB (in case "dB" is appended to the specified value)
1873 or amplitude ratio. Default value is @code{0}.
1876 Set the count for trimming silence from the end of audio.
1877 To remove silence from the middle of a file, specify a @var{stop_periods}
1878 that is negative. This value is then treated as a positive value and is
1879 used to indicate the effect should restart processing as specified by
1880 @var{start_periods}, making it suitable for removing periods of silence
1881 in the middle of the audio.
1882 Default value is @code{0}.
1885 Specify a duration of silence that must exist before audio is not copied any
1886 more. By specifying a higher duration, silence that is wanted can be left in
1888 Default value is @code{0}.
1890 @item stop_threshold
1891 This is the same as @option{start_threshold} but for trimming silence from
1893 Can be specified in dB (in case "dB" is appended to the specified value)
1894 or amplitude ratio. Default value is @code{0}.
1897 This indicate that @var{stop_duration} length of audio should be left intact
1898 at the beginning of each period of silence.
1899 For example, if you want to remove long pauses between words but do not want
1900 to remove the pauses completely. Default value is @code{0}.
1904 @subsection Examples
1908 The following example shows how this filter can be used to start a recording
1909 that does not contain the delay at the start which usually occurs between
1910 pressing the record button and the start of the performance:
1912 silenceremove=1:5:0.02
1918 Boost or cut treble (upper) frequencies of the audio using a two-pole
1919 shelving filter with a response similar to that of a standard
1920 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1922 The filter accepts the following options:
1926 Give the gain at whichever is the lower of ~22 kHz and the
1927 Nyquist frequency. Its useful range is about -20 (for a large cut)
1928 to +20 (for a large boost). Beware of clipping when using a positive gain.
1931 Set the filter's central frequency and so can be used
1932 to extend or reduce the frequency range to be boosted or cut.
1933 The default value is @code{3000} Hz.
1936 Set method to specify band-width of filter.
1949 Determine how steep is the filter's shelf transition.
1954 Adjust the input audio volume.
1956 It accepts the following parameters:
1960 Set audio volume expression.
1962 Output values are clipped to the maximum value.
1964 The output audio volume is given by the relation:
1966 @var{output_volume} = @var{volume} * @var{input_volume}
1969 The default value for @var{volume} is "1.0".
1972 This parameter represents the mathematical precision.
1974 It determines which input sample formats will be allowed, which affects the
1975 precision of the volume scaling.
1979 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
1981 32-bit floating-point; this limits input sample format to FLT. (default)
1983 64-bit floating-point; this limits input sample format to DBL.
1987 Choose the behaviour on encountering ReplayGain side data in input frames.
1991 Remove ReplayGain side data, ignoring its contents (the default).
1994 Ignore ReplayGain side data, but leave it in the frame.
1997 Prefer the track gain, if present.
2000 Prefer the album gain, if present.
2003 @item replaygain_preamp
2004 Pre-amplification gain in dB to apply to the selected replaygain gain.
2006 Default value for @var{replaygain_preamp} is 0.0.
2009 Set when the volume expression is evaluated.
2011 It accepts the following values:
2014 only evaluate expression once during the filter initialization, or
2015 when the @samp{volume} command is sent
2018 evaluate expression for each incoming frame
2021 Default value is @samp{once}.
2024 The volume expression can contain the following parameters.
2028 frame number (starting at zero)
2031 @item nb_consumed_samples
2032 number of samples consumed by the filter
2034 number of samples in the current frame
2036 original frame position in the file
2042 PTS at start of stream
2044 time at start of stream
2050 last set volume value
2053 Note that when @option{eval} is set to @samp{once} only the
2054 @var{sample_rate} and @var{tb} variables are available, all other
2055 variables will evaluate to NAN.
2057 @subsection Commands
2059 This filter supports the following commands:
2062 Modify the volume expression.
2063 The command accepts the same syntax of the corresponding option.
2065 If the specified expression is not valid, it is kept at its current
2067 @item replaygain_noclip
2068 Prevent clipping by limiting the gain applied.
2070 Default value for @var{replaygain_noclip} is 1.
2074 @subsection Examples
2078 Halve the input audio volume:
2082 volume=volume=-6.0206dB
2085 In all the above example the named key for @option{volume} can be
2086 omitted, for example like in:
2092 Increase input audio power by 6 decibels using fixed-point precision:
2094 volume=volume=6dB:precision=fixed
2098 Fade volume after time 10 with an annihilation period of 5 seconds:
2100 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
2104 @section volumedetect
2106 Detect the volume of the input video.
2108 The filter has no parameters. The input is not modified. Statistics about
2109 the volume will be printed in the log when the input stream end is reached.
2111 In particular it will show the mean volume (root mean square), maximum
2112 volume (on a per-sample basis), and the beginning of a histogram of the
2113 registered volume values (from the maximum value to a cumulated 1/1000 of
2116 All volumes are in decibels relative to the maximum PCM value.
2118 @subsection Examples
2120 Here is an excerpt of the output:
2122 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2123 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2124 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2125 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2126 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2127 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2128 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2129 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2130 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2136 The mean square energy is approximately -27 dB, or 10^-2.7.
2138 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2140 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2143 In other words, raising the volume by +4 dB does not cause any clipping,
2144 raising it by +5 dB causes clipping for 6 samples, etc.
2146 @c man end AUDIO FILTERS
2148 @chapter Audio Sources
2149 @c man begin AUDIO SOURCES
2151 Below is a description of the currently available audio sources.
2155 Buffer audio frames, and make them available to the filter chain.
2157 This source is mainly intended for a programmatic use, in particular
2158 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2160 It accepts the following parameters:
2164 The timebase which will be used for timestamps of submitted frames. It must be
2165 either a floating-point number or in @var{numerator}/@var{denominator} form.
2168 The sample rate of the incoming audio buffers.
2171 The sample format of the incoming audio buffers.
2172 Either a sample format name or its corresponding integer representation from
2173 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2175 @item channel_layout
2176 The channel layout of the incoming audio buffers.
2177 Either a channel layout name from channel_layout_map in
2178 @file{libavutil/channel_layout.c} or its corresponding integer representation
2179 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2182 The number of channels of the incoming audio buffers.
2183 If both @var{channels} and @var{channel_layout} are specified, then they
2188 @subsection Examples
2191 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2194 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2195 Since the sample format with name "s16p" corresponds to the number
2196 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2199 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2204 Generate an audio signal specified by an expression.
2206 This source accepts in input one or more expressions (one for each
2207 channel), which are evaluated and used to generate a corresponding
2210 This source accepts the following options:
2214 Set the '|'-separated expressions list for each separate channel. In case the
2215 @option{channel_layout} option is not specified, the selected channel layout
2216 depends on the number of provided expressions. Otherwise the last
2217 specified expression is applied to the remaining output channels.
2219 @item channel_layout, c
2220 Set the channel layout. The number of channels in the specified layout
2221 must be equal to the number of specified expressions.
2224 Set the minimum duration of the sourced audio. See
2225 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2226 for the accepted syntax.
2227 Note that the resulting duration may be greater than the specified
2228 duration, as the generated audio is always cut at the end of a
2231 If not specified, or the expressed duration is negative, the audio is
2232 supposed to be generated forever.
2235 Set the number of samples per channel per each output frame,
2238 @item sample_rate, s
2239 Specify the sample rate, default to 44100.
2242 Each expression in @var{exprs} can contain the following constants:
2246 number of the evaluated sample, starting from 0
2249 time of the evaluated sample expressed in seconds, starting from 0
2256 @subsection Examples
2266 Generate a sin signal with frequency of 440 Hz, set sample rate to
2269 aevalsrc="sin(440*2*PI*t):s=8000"
2273 Generate a two channels signal, specify the channel layout (Front
2274 Center + Back Center) explicitly:
2276 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2280 Generate white noise:
2282 aevalsrc="-2+random(0)"
2286 Generate an amplitude modulated signal:
2288 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2292 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2294 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2301 The null audio source, return unprocessed audio frames. It is mainly useful
2302 as a template and to be employed in analysis / debugging tools, or as
2303 the source for filters which ignore the input data (for example the sox
2306 This source accepts the following options:
2310 @item channel_layout, cl
2312 Specifies the channel layout, and can be either an integer or a string
2313 representing a channel layout. The default value of @var{channel_layout}
2316 Check the channel_layout_map definition in
2317 @file{libavutil/channel_layout.c} for the mapping between strings and
2318 channel layout values.
2320 @item sample_rate, r
2321 Specifies the sample rate, and defaults to 44100.
2324 Set the number of samples per requested frames.
2328 @subsection Examples
2332 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2334 anullsrc=r=48000:cl=4
2338 Do the same operation with a more obvious syntax:
2340 anullsrc=r=48000:cl=mono
2344 All the parameters need to be explicitly defined.
2348 Synthesize a voice utterance using the libflite library.
2350 To enable compilation of this filter you need to configure FFmpeg with
2351 @code{--enable-libflite}.
2353 Note that the flite library is not thread-safe.
2355 The filter accepts the following options:
2360 If set to 1, list the names of the available voices and exit
2361 immediately. Default value is 0.
2364 Set the maximum number of samples per frame. Default value is 512.
2367 Set the filename containing the text to speak.
2370 Set the text to speak.
2373 Set the voice to use for the speech synthesis. Default value is
2374 @code{kal}. See also the @var{list_voices} option.
2377 @subsection Examples
2381 Read from file @file{speech.txt}, and synthesize the text using the
2382 standard flite voice:
2384 flite=textfile=speech.txt
2388 Read the specified text selecting the @code{slt} voice:
2390 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2394 Input text to ffmpeg:
2396 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2400 Make @file{ffplay} speak the specified text, using @code{flite} and
2401 the @code{lavfi} device:
2403 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2407 For more information about libflite, check:
2408 @url{http://www.speech.cs.cmu.edu/flite/}
2412 Generate an audio signal made of a sine wave with amplitude 1/8.
2414 The audio signal is bit-exact.
2416 The filter accepts the following options:
2421 Set the carrier frequency. Default is 440 Hz.
2423 @item beep_factor, b
2424 Enable a periodic beep every second with frequency @var{beep_factor} times
2425 the carrier frequency. Default is 0, meaning the beep is disabled.
2427 @item sample_rate, r
2428 Specify the sample rate, default is 44100.
2431 Specify the duration of the generated audio stream.
2433 @item samples_per_frame
2434 Set the number of samples per output frame, default is 1024.
2437 @subsection Examples
2442 Generate a simple 440 Hz sine wave:
2448 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2452 sine=frequency=220:beep_factor=4:duration=5
2457 @c man end AUDIO SOURCES
2459 @chapter Audio Sinks
2460 @c man begin AUDIO SINKS
2462 Below is a description of the currently available audio sinks.
2464 @section abuffersink
2466 Buffer audio frames, and make them available to the end of filter chain.
2468 This sink is mainly intended for programmatic use, in particular
2469 through the interface defined in @file{libavfilter/buffersink.h}
2470 or the options system.
2472 It accepts a pointer to an AVABufferSinkContext structure, which
2473 defines the incoming buffers' formats, to be passed as the opaque
2474 parameter to @code{avfilter_init_filter} for initialization.
2477 Null audio sink; do absolutely nothing with the input audio. It is
2478 mainly useful as a template and for use in analysis / debugging
2481 @c man end AUDIO SINKS
2483 @chapter Video Filters
2484 @c man begin VIDEO FILTERS
2486 When you configure your FFmpeg build, you can disable any of the
2487 existing filters using @code{--disable-filters}.
2488 The configure output will show the video filters included in your
2491 Below is a description of the currently available video filters.
2493 @section alphaextract
2495 Extract the alpha component from the input as a grayscale video. This
2496 is especially useful with the @var{alphamerge} filter.
2500 Add or replace the alpha component of the primary input with the
2501 grayscale value of a second input. This is intended for use with
2502 @var{alphaextract} to allow the transmission or storage of frame
2503 sequences that have alpha in a format that doesn't support an alpha
2506 For example, to reconstruct full frames from a normal YUV-encoded video
2507 and a separate video created with @var{alphaextract}, you might use:
2509 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2512 Since this filter is designed for reconstruction, it operates on frame
2513 sequences without considering timestamps, and terminates when either
2514 input reaches end of stream. This will cause problems if your encoding
2515 pipeline drops frames. If you're trying to apply an image as an
2516 overlay to a video stream, consider the @var{overlay} filter instead.
2520 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2521 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2522 Substation Alpha) subtitles files.
2524 This filter accepts the following option in addition to the common options from
2525 the @ref{subtitles} filter:
2529 Set the shaping engine
2531 Available values are:
2534 The default libass shaping engine, which is the best available.
2536 Fast, font-agnostic shaper that can do only substitutions
2538 Slower shaper using OpenType for substitutions and positioning
2541 The default is @code{auto}.
2546 Compute the bounding box for the non-black pixels in the input frame
2549 This filter computes the bounding box containing all the pixels with a
2550 luminance value greater than the minimum allowed value.
2551 The parameters describing the bounding box are printed on the filter
2554 The filter accepts the following option:
2558 Set the minimal luminance value. Default is @code{16}.
2561 @section blackdetect
2563 Detect video intervals that are (almost) completely black. Can be
2564 useful to detect chapter transitions, commercials, or invalid
2565 recordings. Output lines contains the time for the start, end and
2566 duration of the detected black interval expressed in seconds.
2568 In order to display the output lines, you need to set the loglevel at
2569 least to the AV_LOG_INFO value.
2571 The filter accepts the following options:
2574 @item black_min_duration, d
2575 Set the minimum detected black duration expressed in seconds. It must
2576 be a non-negative floating point number.
2578 Default value is 2.0.
2580 @item picture_black_ratio_th, pic_th
2581 Set the threshold for considering a picture "black".
2582 Express the minimum value for the ratio:
2584 @var{nb_black_pixels} / @var{nb_pixels}
2587 for which a picture is considered black.
2588 Default value is 0.98.
2590 @item pixel_black_th, pix_th
2591 Set the threshold for considering a pixel "black".
2593 The threshold expresses the maximum pixel luminance value for which a
2594 pixel is considered "black". The provided value is scaled according to
2595 the following equation:
2597 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2600 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2601 the input video format, the range is [0-255] for YUV full-range
2602 formats and [16-235] for YUV non full-range formats.
2604 Default value is 0.10.
2607 The following example sets the maximum pixel threshold to the minimum
2608 value, and detects only black intervals of 2 or more seconds:
2610 blackdetect=d=2:pix_th=0.00
2615 Detect frames that are (almost) completely black. Can be useful to
2616 detect chapter transitions or commercials. Output lines consist of
2617 the frame number of the detected frame, the percentage of blackness,
2618 the position in the file if known or -1 and the timestamp in seconds.
2620 In order to display the output lines, you need to set the loglevel at
2621 least to the AV_LOG_INFO value.
2623 It accepts the following parameters:
2628 The percentage of the pixels that have to be below the threshold; it defaults to
2631 @item threshold, thresh
2632 The threshold below which a pixel value is considered black; it defaults to
2637 @section blend, tblend
2639 Blend two video frames into each other.
2641 The @code{blend} filter takes two input streams and outputs one
2642 stream, the first input is the "top" layer and second input is
2643 "bottom" layer. Output terminates when shortest input terminates.
2645 The @code{tblend} (time blend) filter takes two consecutive frames
2646 from one single stream, and outputs the result obtained by blending
2647 the new frame on top of the old frame.
2649 A description of the accepted options follows.
2657 Set blend mode for specific pixel component or all pixel components in case
2658 of @var{all_mode}. Default value is @code{normal}.
2660 Available values for component modes are:
2694 Set blend opacity for specific pixel component or all pixel components in case
2695 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2702 Set blend expression for specific pixel component or all pixel components in case
2703 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2705 The expressions can use the following variables:
2709 The sequential number of the filtered frame, starting from @code{0}.
2713 the coordinates of the current sample
2717 the width and height of currently filtered plane
2721 Width and height scale depending on the currently filtered plane. It is the
2722 ratio between the corresponding luma plane number of pixels and the current
2723 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2724 @code{0.5,0.5} for chroma planes.
2727 Time of the current frame, expressed in seconds.
2730 Value of pixel component at current location for first video frame (top layer).
2733 Value of pixel component at current location for second video frame (bottom layer).
2737 Force termination when the shortest input terminates. Default is
2738 @code{0}. This option is only defined for the @code{blend} filter.
2741 Continue applying the last bottom frame after the end of the stream. A value of
2742 @code{0} disable the filter after the last frame of the bottom layer is reached.
2743 Default is @code{1}. This option is only defined for the @code{blend} filter.
2746 @subsection Examples
2750 Apply transition from bottom layer to top layer in first 10 seconds:
2752 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2756 Apply 1x1 checkerboard effect:
2758 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2762 Apply uncover left effect:
2764 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2768 Apply uncover down effect:
2770 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2774 Apply uncover up-left effect:
2776 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2780 Display differences between the current and the previous frame:
2782 tblend=all_mode=difference128
2788 Apply a boxblur algorithm to the input video.
2790 It accepts the following parameters:
2794 @item luma_radius, lr
2795 @item luma_power, lp
2796 @item chroma_radius, cr
2797 @item chroma_power, cp
2798 @item alpha_radius, ar
2799 @item alpha_power, ap
2803 A description of the accepted options follows.
2806 @item luma_radius, lr
2807 @item chroma_radius, cr
2808 @item alpha_radius, ar
2809 Set an expression for the box radius in pixels used for blurring the
2810 corresponding input plane.
2812 The radius value must be a non-negative number, and must not be
2813 greater than the value of the expression @code{min(w,h)/2} for the
2814 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2817 Default value for @option{luma_radius} is "2". If not specified,
2818 @option{chroma_radius} and @option{alpha_radius} default to the
2819 corresponding value set for @option{luma_radius}.
2821 The expressions can contain the following constants:
2825 The input width and height in pixels.
2829 The input chroma image width and height in pixels.
2833 The horizontal and vertical chroma subsample values. For example, for the
2834 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
2837 @item luma_power, lp
2838 @item chroma_power, cp
2839 @item alpha_power, ap
2840 Specify how many times the boxblur filter is applied to the
2841 corresponding plane.
2843 Default value for @option{luma_power} is 2. If not specified,
2844 @option{chroma_power} and @option{alpha_power} default to the
2845 corresponding value set for @option{luma_power}.
2847 A value of 0 will disable the effect.
2850 @subsection Examples
2854 Apply a boxblur filter with the luma, chroma, and alpha radii
2857 boxblur=luma_radius=2:luma_power=1
2862 Set the luma radius to 2, and alpha and chroma radius to 0:
2864 boxblur=2:1:cr=0:ar=0
2868 Set the luma and chroma radii to a fraction of the video dimension:
2870 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2876 Visualize information exported by some codecs.
2878 Some codecs can export information through frames using side-data or other
2879 means. For example, some MPEG based codecs export motion vectors through the
2880 @var{export_mvs} flag in the codec @option{flags2} option.
2882 The filter accepts the following option:
2886 Set motion vectors to visualize.
2888 Available flags for @var{mv} are:
2892 forward predicted MVs of P-frames
2894 forward predicted MVs of B-frames
2896 backward predicted MVs of B-frames
2900 @subsection Examples
2904 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
2906 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
2910 @section colorbalance
2911 Modify intensity of primary colors (red, green and blue) of input frames.
2913 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2914 regions for the red-cyan, green-magenta or blue-yellow balance.
2916 A positive adjustment value shifts the balance towards the primary color, a negative
2917 value towards the complementary color.
2919 The filter accepts the following options:
2925 Adjust red, green and blue shadows (darkest pixels).
2930 Adjust red, green and blue midtones (medium pixels).
2935 Adjust red, green and blue highlights (brightest pixels).
2937 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2940 @subsection Examples
2944 Add red color cast to shadows:
2950 @section colorlevels
2952 Adjust video input frames using levels.
2954 The filter accepts the following options:
2961 Adjust red, green, blue and alpha input black point.
2962 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2968 Adjust red, green, blue and alpha input white point.
2969 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
2971 Input levels are used to lighten highlights (bright tones), darken shadows
2972 (dark tones), change the balance of bright and dark tones.
2978 Adjust red, green, blue and alpha output black point.
2979 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
2985 Adjust red, green, blue and alpha output white point.
2986 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
2988 Output levels allows manual selection of a constrained output level range.
2991 @subsection Examples
2995 Make video output darker:
2997 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
3003 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
3007 Make video output lighter:
3009 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
3013 Increase brightness:
3015 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
3019 @section colorchannelmixer
3021 Adjust video input frames by re-mixing color channels.
3023 This filter modifies a color channel by adding the values associated to
3024 the other channels of the same pixels. For example if the value to
3025 modify is red, the output value will be:
3027 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
3030 The filter accepts the following options:
3037 Adjust contribution of input red, green, blue and alpha channels for output red channel.
3038 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
3044 Adjust contribution of input red, green, blue and alpha channels for output green channel.
3045 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
3051 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
3052 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
3058 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
3059 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
3061 Allowed ranges for options are @code{[-2.0, 2.0]}.
3064 @subsection Examples
3068 Convert source to grayscale:
3070 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
3073 Simulate sepia tones:
3075 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
3079 @section colormatrix
3081 Convert color matrix.
3083 The filter accepts the following options:
3088 Specify the source and destination color matrix. Both values must be
3091 The accepted values are:
3107 For example to convert from BT.601 to SMPTE-240M, use the command:
3109 colormatrix=bt601:smpte240m
3114 Copy the input source unchanged to the output. This is mainly useful for
3119 Crop the input video to given dimensions.
3121 It accepts the following parameters:
3125 The width of the output video. It defaults to @code{iw}.
3126 This expression is evaluated only once during the filter
3130 The height of the output video. It defaults to @code{ih}.
3131 This expression is evaluated only once during the filter
3135 The horizontal position, in the input video, of the left edge of the output
3136 video. It defaults to @code{(in_w-out_w)/2}.
3137 This expression is evaluated per-frame.
3140 The vertical position, in the input video, of the top edge of the output video.
3141 It defaults to @code{(in_h-out_h)/2}.
3142 This expression is evaluated per-frame.
3145 If set to 1 will force the output display aspect ratio
3146 to be the same of the input, by changing the output sample aspect
3147 ratio. It defaults to 0.
3150 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
3151 expressions containing the following constants:
3156 The computed values for @var{x} and @var{y}. They are evaluated for
3161 The input width and height.
3165 These are the same as @var{in_w} and @var{in_h}.
3169 The output (cropped) width and height.
3173 These are the same as @var{out_w} and @var{out_h}.
3176 same as @var{iw} / @var{ih}
3179 input sample aspect ratio
3182 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
3186 horizontal and vertical chroma subsample values. For example for the
3187 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3190 The number of the input frame, starting from 0.
3193 the position in the file of the input frame, NAN if unknown
3196 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
3200 The expression for @var{out_w} may depend on the value of @var{out_h},
3201 and the expression for @var{out_h} may depend on @var{out_w}, but they
3202 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
3203 evaluated after @var{out_w} and @var{out_h}.
3205 The @var{x} and @var{y} parameters specify the expressions for the
3206 position of the top-left corner of the output (non-cropped) area. They
3207 are evaluated for each frame. If the evaluated value is not valid, it
3208 is approximated to the nearest valid value.
3210 The expression for @var{x} may depend on @var{y}, and the expression
3211 for @var{y} may depend on @var{x}.
3213 @subsection Examples
3217 Crop area with size 100x100 at position (12,34).
3222 Using named options, the example above becomes:
3224 crop=w=100:h=100:x=12:y=34
3228 Crop the central input area with size 100x100:
3234 Crop the central input area with size 2/3 of the input video:
3236 crop=2/3*in_w:2/3*in_h
3240 Crop the input video central square:
3247 Delimit the rectangle with the top-left corner placed at position
3248 100:100 and the right-bottom corner corresponding to the right-bottom
3249 corner of the input image.
3251 crop=in_w-100:in_h-100:100:100
3255 Crop 10 pixels from the left and right borders, and 20 pixels from
3256 the top and bottom borders
3258 crop=in_w-2*10:in_h-2*20
3262 Keep only the bottom right quarter of the input image:
3264 crop=in_w/2:in_h/2:in_w/2:in_h/2
3268 Crop height for getting Greek harmony:
3270 crop=in_w:1/PHI*in_w
3274 Apply trembling effect:
3276 crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(n/10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(n/7)
3280 Apply erratic camera effect depending on timestamp:
3282 crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)"
3286 Set x depending on the value of y:
3288 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3294 Auto-detect the crop size.
3296 It calculates the necessary cropping parameters and prints the
3297 recommended parameters via the logging system. The detected dimensions
3298 correspond to the non-black area of the input video.
3300 It accepts the following parameters:
3305 Set higher black value threshold, which can be optionally specified
3306 from nothing (0) to everything (255 for 8bit based formats). An intensity
3307 value greater to the set value is considered non-black. It defaults to 24.
3308 You can also specify a value between 0.0 and 1.0 which will be scaled depending
3309 on the bitdepth of the pixel format.
3312 The value which the width/height should be divisible by. It defaults to
3313 16. The offset is automatically adjusted to center the video. Use 2 to
3314 get only even dimensions (needed for 4:2:2 video). 16 is best when
3315 encoding to most video codecs.
3317 @item reset_count, reset
3318 Set the counter that determines after how many frames cropdetect will
3319 reset the previously detected largest video area and start over to
3320 detect the current optimal crop area. Default value is 0.
3322 This can be useful when channel logos distort the video area. 0
3323 indicates 'never reset', and returns the largest area encountered during
3330 Apply color adjustments using curves.
3332 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3333 component (red, green and blue) has its values defined by @var{N} key points
3334 tied from each other using a smooth curve. The x-axis represents the pixel
3335 values from the input frame, and the y-axis the new pixel values to be set for
3338 By default, a component curve is defined by the two points @var{(0;0)} and
3339 @var{(1;1)}. This creates a straight line where each original pixel value is
3340 "adjusted" to its own value, which means no change to the image.
3342 The filter allows you to redefine these two points and add some more. A new
3343 curve (using a natural cubic spline interpolation) will be define to pass
3344 smoothly through all these new coordinates. The new defined points needs to be
3345 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3346 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3347 the vector spaces, the values will be clipped accordingly.
3349 If there is no key point defined in @code{x=0}, the filter will automatically
3350 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3351 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3353 The filter accepts the following options:
3357 Select one of the available color presets. This option can be used in addition
3358 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3359 options takes priority on the preset values.
3360 Available presets are:
3363 @item color_negative
3366 @item increase_contrast
3368 @item linear_contrast
3369 @item medium_contrast
3371 @item strong_contrast
3374 Default is @code{none}.
3376 Set the master key points. These points will define a second pass mapping. It
3377 is sometimes called a "luminance" or "value" mapping. It can be used with
3378 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3379 post-processing LUT.
3381 Set the key points for the red component.
3383 Set the key points for the green component.
3385 Set the key points for the blue component.
3387 Set the key points for all components (not including master).
3388 Can be used in addition to the other key points component
3389 options. In this case, the unset component(s) will fallback on this
3390 @option{all} setting.
3392 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3395 To avoid some filtergraph syntax conflicts, each key points list need to be
3396 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3398 @subsection Examples
3402 Increase slightly the middle level of blue:
3404 curves=blue='0.5/0.58'
3410 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3412 Here we obtain the following coordinates for each components:
3415 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3417 @code{(0;0) (0.50;0.48) (1;1)}
3419 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3423 The previous example can also be achieved with the associated built-in preset:
3425 curves=preset=vintage
3435 Use a Photoshop preset and redefine the points of the green component:
3437 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3443 Denoise frames using 2D DCT (frequency domain filtering).
3445 This filter is not designed for real time.
3447 The filter accepts the following options:
3451 Set the noise sigma constant.
3453 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3454 coefficient (absolute value) below this threshold with be dropped.
3456 If you need a more advanced filtering, see @option{expr}.
3458 Default is @code{0}.
3461 Set number overlapping pixels for each block. Since the filter can be slow, you
3462 may want to reduce this value, at the cost of a less effective filter and the
3463 risk of various artefacts.
3465 If the overlapping value doesn't allow to process the whole input width or
3466 height, a warning will be displayed and according borders won't be denoised.
3468 Default value is @var{blocksize}-1, which is the best possible setting.
3471 Set the coefficient factor expression.
3473 For each coefficient of a DCT block, this expression will be evaluated as a
3474 multiplier value for the coefficient.
3476 If this is option is set, the @option{sigma} option will be ignored.
3478 The absolute value of the coefficient can be accessed through the @var{c}
3482 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
3483 @var{blocksize}, which is the width and height of the processed blocks.
3485 The default value is @var{3} (8x8) and can be raised to @var{4} for a
3486 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
3487 on the speed processing. Also, a larger block size does not necessarily means a
3491 @subsection Examples
3493 Apply a denoise with a @option{sigma} of @code{4.5}:
3498 The same operation can be achieved using the expression system:
3500 dctdnoiz=e='gte(c, 4.5*3)'
3503 Violent denoise using a block size of @code{16x16}:
3511 Drop duplicated frames at regular intervals.
3513 The filter accepts the following options:
3517 Set the number of frames from which one will be dropped. Setting this to
3518 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3519 Default is @code{5}.
3522 Set the threshold for duplicate detection. If the difference metric for a frame
3523 is less than or equal to this value, then it is declared as duplicate. Default
3527 Set scene change threshold. Default is @code{15}.
3531 Set the size of the x and y-axis blocks used during metric calculations.
3532 Larger blocks give better noise suppression, but also give worse detection of
3533 small movements. Must be a power of two. Default is @code{32}.
3536 Mark main input as a pre-processed input and activate clean source input
3537 stream. This allows the input to be pre-processed with various filters to help
3538 the metrics calculation while keeping the frame selection lossless. When set to
3539 @code{1}, the first stream is for the pre-processed input, and the second
3540 stream is the clean source from where the kept frames are chosen. Default is
3544 Set whether or not chroma is considered in the metric calculations. Default is
3550 Remove judder produced by partially interlaced telecined content.
3552 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3553 source was partially telecined content then the output of @code{pullup,dejudder}
3554 will have a variable frame rate. May change the recorded frame rate of the
3555 container. Aside from that change, this filter will not affect constant frame
3558 The option available in this filter is:
3562 Specify the length of the window over which the judder repeats.
3564 Accepts any integer greater than 1. Useful values are:
3568 If the original was telecined from 24 to 30 fps (Film to NTSC).
3571 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3574 If a mixture of the two.
3577 The default is @samp{4}.
3582 Suppress a TV station logo by a simple interpolation of the surrounding
3583 pixels. Just set a rectangle covering the logo and watch it disappear
3584 (and sometimes something even uglier appear - your mileage may vary).
3586 It accepts the following parameters:
3591 Specify the top left corner coordinates of the logo. They must be
3596 Specify the width and height of the logo to clear. They must be
3600 Specify the thickness of the fuzzy edge of the rectangle (added to
3601 @var{w} and @var{h}). The default value is 4.
3604 When set to 1, a green rectangle is drawn on the screen to simplify
3605 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3606 The default value is 0.
3608 The rectangle is drawn on the outermost pixels which will be (partly)
3609 replaced with interpolated values. The values of the next pixels
3610 immediately outside this rectangle in each direction will be used to
3611 compute the interpolated pixel values inside the rectangle.
3615 @subsection Examples
3619 Set a rectangle covering the area with top left corner coordinates 0,0
3620 and size 100x77, and a band of size 10:
3622 delogo=x=0:y=0:w=100:h=77:band=10
3629 Attempt to fix small changes in horizontal and/or vertical shift. This
3630 filter helps remove camera shake from hand-holding a camera, bumping a
3631 tripod, moving on a vehicle, etc.
3633 The filter accepts the following options:
3641 Specify a rectangular area where to limit the search for motion
3643 If desired the search for motion vectors can be limited to a
3644 rectangular area of the frame defined by its top left corner, width
3645 and height. These parameters have the same meaning as the drawbox
3646 filter which can be used to visualise the position of the bounding
3649 This is useful when simultaneous movement of subjects within the frame
3650 might be confused for camera motion by the motion vector search.
3652 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3653 then the full frame is used. This allows later options to be set
3654 without specifying the bounding box for the motion vector search.
3656 Default - search the whole frame.
3660 Specify the maximum extent of movement in x and y directions in the
3661 range 0-64 pixels. Default 16.
3664 Specify how to generate pixels to fill blanks at the edge of the
3665 frame. Available values are:
3668 Fill zeroes at blank locations
3670 Original image at blank locations
3672 Extruded edge value at blank locations
3674 Mirrored edge at blank locations
3676 Default value is @samp{mirror}.
3679 Specify the blocksize to use for motion search. Range 4-128 pixels,
3683 Specify the contrast threshold for blocks. Only blocks with more than
3684 the specified contrast (difference between darkest and lightest
3685 pixels) will be considered. Range 1-255, default 125.
3688 Specify the search strategy. Available values are:
3691 Set exhaustive search
3693 Set less exhaustive search.
3695 Default value is @samp{exhaustive}.
3698 If set then a detailed log of the motion search is written to the
3702 If set to 1, specify using OpenCL capabilities, only available if
3703 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3709 Draw a colored box on the input image.
3711 It accepts the following parameters:
3716 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3720 The expressions which specify the width and height of the box; if 0 they are interpreted as
3721 the input width and height. It defaults to 0.
3724 Specify the color of the box to write. For the general syntax of this option,
3725 check the "Color" section in the ffmpeg-utils manual. If the special
3726 value @code{invert} is used, the box edge color is the same as the
3727 video with inverted luma.
3730 The expression which sets the thickness of the box edge. Default value is @code{3}.
3732 See below for the list of accepted constants.
3735 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3736 following constants:
3740 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3744 horizontal and vertical chroma subsample values. For example for the
3745 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3749 The input width and height.
3752 The input sample aspect ratio.
3756 The x and y offset coordinates where the box is drawn.
3760 The width and height of the drawn box.
3763 The thickness of the drawn box.
3765 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3766 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3770 @subsection Examples
3774 Draw a black box around the edge of the input image:
3780 Draw a box with color red and an opacity of 50%:
3782 drawbox=10:20:200:60:red@@0.5
3785 The previous example can be specified as:
3787 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3791 Fill the box with pink color:
3793 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3797 Draw a 2-pixel red 2.40:1 mask:
3799 drawbox=x=-t:y=0.5*(ih-iw/2.4)-t:w=iw+t*2:h=iw/2.4+t*2:t=2:c=red
3805 Draw a grid on the input image.
3807 It accepts the following parameters:
3812 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3816 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3817 input width and height, respectively, minus @code{thickness}, so image gets
3818 framed. Default to 0.
3821 Specify the color of the grid. For the general syntax of this option,
3822 check the "Color" section in the ffmpeg-utils manual. If the special
3823 value @code{invert} is used, the grid color is the same as the
3824 video with inverted luma.
3827 The expression which sets the thickness of the grid line. Default value is @code{1}.
3829 See below for the list of accepted constants.
3832 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3833 following constants:
3837 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3841 horizontal and vertical chroma subsample values. For example for the
3842 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3846 The input grid cell width and height.
3849 The input sample aspect ratio.
3853 The x and y coordinates of some point of grid intersection (meant to configure offset).
3857 The width and height of the drawn cell.
3860 The thickness of the drawn cell.
3862 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3863 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3867 @subsection Examples
3871 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3873 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3877 Draw a white 3x3 grid with an opacity of 50%:
3879 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3886 Draw a text string or text from a specified file on top of a video, using the
3887 libfreetype library.
3889 To enable compilation of this filter, you need to configure FFmpeg with
3890 @code{--enable-libfreetype}.
3891 To enable default font fallback and the @var{font} option you need to
3892 configure FFmpeg with @code{--enable-libfontconfig}.
3893 To enable the @var{text_shaping} option, you need to configure FFmpeg with
3894 @code{--enable-libfribidi}.
3898 It accepts the following parameters:
3903 Used to draw a box around text using the background color.
3904 The value must be either 1 (enable) or 0 (disable).
3905 The default value of @var{box} is 0.
3908 The color to be used for drawing box around text. For the syntax of this
3909 option, check the "Color" section in the ffmpeg-utils manual.
3911 The default value of @var{boxcolor} is "white".
3914 Set the width of the border to be drawn around the text using @var{bordercolor}.
3915 The default value of @var{borderw} is 0.
3918 Set the color to be used for drawing border around text. For the syntax of this
3919 option, check the "Color" section in the ffmpeg-utils manual.
3921 The default value of @var{bordercolor} is "black".
3924 Select how the @var{text} is expanded. Can be either @code{none},
3925 @code{strftime} (deprecated) or
3926 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3930 If true, check and fix text coords to avoid clipping.
3933 The color to be used for drawing fonts. For the syntax of this option, check
3934 the "Color" section in the ffmpeg-utils manual.
3936 The default value of @var{fontcolor} is "black".
3938 @item fontcolor_expr
3939 String which is expanded the same way as @var{text} to obtain dynamic
3940 @var{fontcolor} value. By default this option has empty value and is not
3941 processed. When this option is set, it overrides @var{fontcolor} option.
3944 The font family to be used for drawing text. By default Sans.
3947 The font file to be used for drawing text. The path must be included.
3948 This parameter is mandatory if the fontconfig support is disabled.
3951 The font size to be used for drawing text.
3952 The default value of @var{fontsize} is 16.
3955 If set to 1, attempt to shape the text (for example, reverse the order of
3956 right-to-left text and join Arabic characters) before drawing it.
3957 Otherwise, just draw the text exactly as given.
3958 By default 1 (if supported).
3961 The flags to be used for loading the fonts.
3963 The flags map the corresponding flags supported by libfreetype, and are
3964 a combination of the following values:
3971 @item vertical_layout
3972 @item force_autohint
3975 @item ignore_global_advance_width
3977 @item ignore_transform
3983 Default value is "default".
3985 For more information consult the documentation for the FT_LOAD_*
3989 The color to be used for drawing a shadow behind the drawn text. For the
3990 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3992 The default value of @var{shadowcolor} is "black".
3996 The x and y offsets for the text shadow position with respect to the
3997 position of the text. They can be either positive or negative
3998 values. The default value for both is "0".
4001 The starting frame number for the n/frame_num variable. The default value
4005 The size in number of spaces to use for rendering the tab.
4009 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
4010 format. It can be used with or without text parameter. @var{timecode_rate}
4011 option must be specified.
4013 @item timecode_rate, rate, r
4014 Set the timecode frame rate (timecode only).
4017 The text string to be drawn. The text must be a sequence of UTF-8
4019 This parameter is mandatory if no file is specified with the parameter
4023 A text file containing text to be drawn. The text must be a sequence
4024 of UTF-8 encoded characters.
4026 This parameter is mandatory if no text string is specified with the
4027 parameter @var{text}.
4029 If both @var{text} and @var{textfile} are specified, an error is thrown.
4032 If set to 1, the @var{textfile} will be reloaded before each frame.
4033 Be sure to update it atomically, or it may be read partially, or even fail.
4037 The expressions which specify the offsets where text will be drawn
4038 within the video frame. They are relative to the top/left border of the
4041 The default value of @var{x} and @var{y} is "0".
4043 See below for the list of accepted constants and functions.
4046 The parameters for @var{x} and @var{y} are expressions containing the
4047 following constants and functions:
4051 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
4055 horizontal and vertical chroma subsample values. For example for the
4056 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4059 the height of each text line
4067 @item max_glyph_a, ascent
4068 the maximum distance from the baseline to the highest/upper grid
4069 coordinate used to place a glyph outline point, for all the rendered
4071 It is a positive value, due to the grid's orientation with the Y axis
4074 @item max_glyph_d, descent
4075 the maximum distance from the baseline to the lowest grid coordinate
4076 used to place a glyph outline point, for all the rendered glyphs.
4077 This is a negative value, due to the grid's orientation, with the Y axis
4081 maximum glyph height, that is the maximum height for all the glyphs
4082 contained in the rendered text, it is equivalent to @var{ascent} -
4086 maximum glyph width, that is the maximum width for all the glyphs
4087 contained in the rendered text
4090 the number of input frame, starting from 0
4092 @item rand(min, max)
4093 return a random number included between @var{min} and @var{max}
4096 The input sample aspect ratio.
4099 timestamp expressed in seconds, NAN if the input timestamp is unknown
4102 the height of the rendered text
4105 the width of the rendered text
4109 the x and y offset coordinates where the text is drawn.
4111 These parameters allow the @var{x} and @var{y} expressions to refer
4112 each other, so you can for example specify @code{y=x/dar}.
4115 @anchor{drawtext_expansion}
4116 @subsection Text expansion
4118 If @option{expansion} is set to @code{strftime},
4119 the filter recognizes strftime() sequences in the provided text and
4120 expands them accordingly. Check the documentation of strftime(). This
4121 feature is deprecated.
4123 If @option{expansion} is set to @code{none}, the text is printed verbatim.
4125 If @option{expansion} is set to @code{normal} (which is the default),
4126 the following expansion mechanism is used.
4128 The backslash character '\', followed by any character, always expands to
4129 the second character.
4131 Sequence of the form @code{%@{...@}} are expanded. The text between the
4132 braces is a function name, possibly followed by arguments separated by ':'.
4133 If the arguments contain special characters or delimiters (':' or '@}'),
4134 they should be escaped.
4136 Note that they probably must also be escaped as the value for the
4137 @option{text} option in the filter argument string and as the filter
4138 argument in the filtergraph description, and possibly also for the shell,
4139 that makes up to four levels of escaping; using a text file avoids these
4142 The following functions are available:
4147 The expression evaluation result.
4149 It must take one argument specifying the expression to be evaluated,
4150 which accepts the same constants and functions as the @var{x} and
4151 @var{y} values. Note that not all constants should be used, for
4152 example the text size is not known when evaluating the expression, so
4153 the constants @var{text_w} and @var{text_h} will have an undefined
4156 @item expr_int_format, eif
4157 Evaluate the expression's value and output as formatted integer.
4159 The first argument is the expression to be evaluated, just as for the @var{expr} function.
4160 The second argument specifies the output format. Allowed values are 'x', 'X', 'd' and
4161 'u'. They are treated exactly as in the printf function.
4162 The third parameter is optional and sets the number of positions taken by the output.
4163 It can be used to add padding with zeros from the left.
4166 The time at which the filter is running, expressed in UTC.
4167 It can accept an argument: a strftime() format string.
4170 The time at which the filter is running, expressed in the local time zone.
4171 It can accept an argument: a strftime() format string.
4174 Frame metadata. It must take one argument specifying metadata key.
4177 The frame number, starting from 0.
4180 A 1 character description of the current picture type.
4183 The timestamp of the current frame.
4184 It can take up to two arguments.
4186 The first argument is the format of the timestamp; it defaults to @code{flt}
4187 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
4188 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
4190 The second argument is an offset added to the timestamp.
4194 @subsection Examples
4198 Draw "Test Text" with font FreeSerif, using the default values for the
4199 optional parameters.
4202 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
4206 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
4207 and y=50 (counting from the top-left corner of the screen), text is
4208 yellow with a red box around it. Both the text and the box have an
4212 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
4213 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
4216 Note that the double quotes are not necessary if spaces are not used
4217 within the parameter list.
4220 Show the text at the center of the video frame:
4222 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
4226 Show a text line sliding from right to left in the last row of the video
4227 frame. The file @file{LONG_LINE} is assumed to contain a single line
4230 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
4234 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
4236 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
4240 Draw a single green letter "g", at the center of the input video.
4241 The glyph baseline is placed at half screen height.
4243 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
4247 Show text for 1 second every 3 seconds:
4249 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
4253 Use fontconfig to set the font. Note that the colons need to be escaped.
4255 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
4259 Print the date of a real-time encoding (see strftime(3)):
4261 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
4265 Show text fading in and out (appearing/disappearing):
4268 DS=1.0 # display start
4269 DE=10.0 # display end
4270 FID=1.5 # fade in duration
4271 FOD=5 # fade out duration
4272 ffplay -f lavfi "color,drawtext=text=TEST:fontsize=50:fontfile=FreeSerif.ttf:fontcolor_expr=ff0000%@{eif\\\\: clip(255*(1*between(t\\, $DS + $FID\\, $DE - $FOD) + ((t - $DS)/$FID)*between(t\\, $DS\\, $DS + $FID) + (-(t - $DE)/$FOD)*between(t\\, $DE - $FOD\\, $DE) )\\, 0\\, 255) \\\\: x\\\\: 2 @}"
4277 For more information about libfreetype, check:
4278 @url{http://www.freetype.org/}.
4280 For more information about fontconfig, check:
4281 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
4283 For more information about libfribidi, check:
4284 @url{http://fribidi.org/}.
4288 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
4290 The filter accepts the following options:
4295 Set low and high threshold values used by the Canny thresholding
4298 The high threshold selects the "strong" edge pixels, which are then
4299 connected through 8-connectivity with the "weak" edge pixels selected
4300 by the low threshold.
4302 @var{low} and @var{high} threshold values must be chosen in the range
4303 [0,1], and @var{low} should be lesser or equal to @var{high}.
4305 Default value for @var{low} is @code{20/255}, and default value for @var{high}
4309 Define the drawing mode.
4313 Draw white/gray wires on black background.
4316 Mix the colors to create a paint/cartoon effect.
4319 Default value is @var{wires}.
4322 @subsection Examples
4326 Standard edge detection with custom values for the hysteresis thresholding:
4328 edgedetect=low=0.1:high=0.4
4332 Painting effect without thresholding:
4334 edgedetect=mode=colormix:high=0
4338 @section extractplanes
4340 Extract color channel components from input video stream into
4341 separate grayscale video streams.
4343 The filter accepts the following option:
4347 Set plane(s) to extract.
4349 Available values for planes are:
4360 Choosing planes not available in the input will result in an error.
4361 That means you cannot select @code{r}, @code{g}, @code{b} planes
4362 with @code{y}, @code{u}, @code{v} planes at same time.
4365 @subsection Examples
4369 Extract luma, u and v color channel component from input video frame
4370 into 3 grayscale outputs:
4372 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
4378 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4380 For each input image, the filter will compute the optimal mapping from
4381 the input to the output given the codebook length, that is the number
4382 of distinct output colors.
4384 This filter accepts the following options.
4387 @item codebook_length, l
4388 Set codebook length. The value must be a positive integer, and
4389 represents the number of distinct output colors. Default value is 256.
4392 Set the maximum number of iterations to apply for computing the optimal
4393 mapping. The higher the value the better the result and the higher the
4394 computation time. Default value is 1.
4397 Set a random seed, must be an integer included between 0 and
4398 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4399 will try to use a good random seed on a best effort basis.
4404 Apply a fade-in/out effect to the input video.
4406 It accepts the following parameters:
4410 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4412 Default is @code{in}.
4414 @item start_frame, s
4415 Specify the number of the frame to start applying the fade
4416 effect at. Default is 0.
4419 The number of frames that the fade effect lasts. At the end of the
4420 fade-in effect, the output video will have the same intensity as the input video.
4421 At the end of the fade-out transition, the output video will be filled with the
4422 selected @option{color}.
4426 If set to 1, fade only alpha channel, if one exists on the input.
4429 @item start_time, st
4430 Specify the timestamp (in seconds) of the frame to start to apply the fade
4431 effect. If both start_frame and start_time are specified, the fade will start at
4432 whichever comes last. Default is 0.
4435 The number of seconds for which the fade effect has to last. At the end of the
4436 fade-in effect the output video will have the same intensity as the input video,
4437 at the end of the fade-out transition the output video will be filled with the
4438 selected @option{color}.
4439 If both duration and nb_frames are specified, duration is used. Default is 0.
4442 Specify the color of the fade. Default is "black".
4445 @subsection Examples
4449 Fade in the first 30 frames of video:
4454 The command above is equivalent to:
4460 Fade out the last 45 frames of a 200-frame video:
4463 fade=type=out:start_frame=155:nb_frames=45
4467 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4469 fade=in:0:25, fade=out:975:25
4473 Make the first 5 frames yellow, then fade in from frame 5-24:
4475 fade=in:5:20:color=yellow
4479 Fade in alpha over first 25 frames of video:
4481 fade=in:0:25:alpha=1
4485 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4487 fade=t=in:st=5.5:d=0.5
4494 Extract a single field from an interlaced image using stride
4495 arithmetic to avoid wasting CPU time. The output frames are marked as
4498 The filter accepts the following options:
4502 Specify whether to extract the top (if the value is @code{0} or
4503 @code{top}) or the bottom field (if the value is @code{1} or
4509 Field matching filter for inverse telecine. It is meant to reconstruct the
4510 progressive frames from a telecined stream. The filter does not drop duplicated
4511 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4512 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4514 The separation of the field matching and the decimation is notably motivated by
4515 the possibility of inserting a de-interlacing filter fallback between the two.
4516 If the source has mixed telecined and real interlaced content,
4517 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4518 But these remaining combed frames will be marked as interlaced, and thus can be
4519 de-interlaced by a later filter such as @ref{yadif} before decimation.
4521 In addition to the various configuration options, @code{fieldmatch} can take an
4522 optional second stream, activated through the @option{ppsrc} option. If
4523 enabled, the frames reconstruction will be based on the fields and frames from
4524 this second stream. This allows the first input to be pre-processed in order to
4525 help the various algorithms of the filter, while keeping the output lossless
4526 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4527 or brightness/contrast adjustments can help.
4529 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4530 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4531 which @code{fieldmatch} is based on. While the semantic and usage are very
4532 close, some behaviour and options names can differ.
4534 The @ref{decimate} filter currently only works for constant frame rate input.
4535 Do not use @code{fieldmatch} and @ref{decimate} if your input has mixed
4536 telecined and progressive content with changing framerate.
4538 The filter accepts the following options:
4542 Specify the assumed field order of the input stream. Available values are:
4546 Auto detect parity (use FFmpeg's internal parity value).
4548 Assume bottom field first.
4550 Assume top field first.
4553 Note that it is sometimes recommended not to trust the parity announced by the
4556 Default value is @var{auto}.
4559 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4560 sense that it won't risk creating jerkiness due to duplicate frames when
4561 possible, but if there are bad edits or blended fields it will end up
4562 outputting combed frames when a good match might actually exist. On the other
4563 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4564 but will almost always find a good frame if there is one. The other values are
4565 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4566 jerkiness and creating duplicate frames versus finding good matches in sections
4567 with bad edits, orphaned fields, blended fields, etc.
4569 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4571 Available values are:
4575 2-way matching (p/c)
4577 2-way matching, and trying 3rd match if still combed (p/c + n)
4579 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4581 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4582 still combed (p/c + n + u/b)
4584 3-way matching (p/c/n)
4586 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4587 detected as combed (p/c/n + u/b)
4590 The parenthesis at the end indicate the matches that would be used for that
4591 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4594 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4597 Default value is @var{pc_n}.
4600 Mark the main input stream as a pre-processed input, and enable the secondary
4601 input stream as the clean source to pick the fields from. See the filter
4602 introduction for more details. It is similar to the @option{clip2} feature from
4605 Default value is @code{0} (disabled).
4608 Set the field to match from. It is recommended to set this to the same value as
4609 @option{order} unless you experience matching failures with that setting. In
4610 certain circumstances changing the field that is used to match from can have a
4611 large impact on matching performance. Available values are:
4615 Automatic (same value as @option{order}).
4617 Match from the bottom field.
4619 Match from the top field.
4622 Default value is @var{auto}.
4625 Set whether or not chroma is included during the match comparisons. In most
4626 cases it is recommended to leave this enabled. You should set this to @code{0}
4627 only if your clip has bad chroma problems such as heavy rainbowing or other
4628 artifacts. Setting this to @code{0} could also be used to speed things up at
4629 the cost of some accuracy.
4631 Default value is @code{1}.
4635 These define an exclusion band which excludes the lines between @option{y0} and
4636 @option{y1} from being included in the field matching decision. An exclusion
4637 band can be used to ignore subtitles, a logo, or other things that may
4638 interfere with the matching. @option{y0} sets the starting scan line and
4639 @option{y1} sets the ending line; all lines in between @option{y0} and
4640 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4641 @option{y0} and @option{y1} to the same value will disable the feature.
4642 @option{y0} and @option{y1} defaults to @code{0}.
4645 Set the scene change detection threshold as a percentage of maximum change on
4646 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4647 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4648 @option{scthresh} is @code{[0.0, 100.0]}.
4650 Default value is @code{12.0}.
4653 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4654 account the combed scores of matches when deciding what match to use as the
4655 final match. Available values are:
4659 No final matching based on combed scores.
4661 Combed scores are only used when a scene change is detected.
4663 Use combed scores all the time.
4666 Default is @var{sc}.
4669 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4670 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4671 Available values are:
4675 No forced calculation.
4677 Force p/c/n calculations.
4679 Force p/c/n/u/b calculations.
4682 Default value is @var{none}.
4685 This is the area combing threshold used for combed frame detection. This
4686 essentially controls how "strong" or "visible" combing must be to be detected.
4687 Larger values mean combing must be more visible and smaller values mean combing
4688 can be less visible or strong and still be detected. Valid settings are from
4689 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4690 be detected as combed). This is basically a pixel difference value. A good
4691 range is @code{[8, 12]}.
4693 Default value is @code{9}.
4696 Sets whether or not chroma is considered in the combed frame decision. Only
4697 disable this if your source has chroma problems (rainbowing, etc.) that are
4698 causing problems for the combed frame detection with chroma enabled. Actually,
4699 using @option{chroma}=@var{0} is usually more reliable, except for the case
4700 where there is chroma only combing in the source.
4702 Default value is @code{0}.
4706 Respectively set the x-axis and y-axis size of the window used during combed
4707 frame detection. This has to do with the size of the area in which
4708 @option{combpel} pixels are required to be detected as combed for a frame to be
4709 declared combed. See the @option{combpel} parameter description for more info.
4710 Possible values are any number that is a power of 2 starting at 4 and going up
4713 Default value is @code{16}.
4716 The number of combed pixels inside any of the @option{blocky} by
4717 @option{blockx} size blocks on the frame for the frame to be detected as
4718 combed. While @option{cthresh} controls how "visible" the combing must be, this
4719 setting controls "how much" combing there must be in any localized area (a
4720 window defined by the @option{blockx} and @option{blocky} settings) on the
4721 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4722 which point no frames will ever be detected as combed). This setting is known
4723 as @option{MI} in TFM/VFM vocabulary.
4725 Default value is @code{80}.
4728 @anchor{p/c/n/u/b meaning}
4729 @subsection p/c/n/u/b meaning
4731 @subsubsection p/c/n
4733 We assume the following telecined stream:
4736 Top fields: 1 2 2 3 4
4737 Bottom fields: 1 2 3 4 4
4740 The numbers correspond to the progressive frame the fields relate to. Here, the
4741 first two frames are progressive, the 3rd and 4th are combed, and so on.
4743 When @code{fieldmatch} is configured to run a matching from bottom
4744 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4749 B 1 2 3 4 4 <-- matching reference
4758 As a result of the field matching, we can see that some frames get duplicated.
4759 To perform a complete inverse telecine, you need to rely on a decimation filter
4760 after this operation. See for instance the @ref{decimate} filter.
4762 The same operation now matching from top fields (@option{field}=@var{top})
4767 T 1 2 2 3 4 <-- matching reference
4777 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4778 basically, they refer to the frame and field of the opposite parity:
4781 @item @var{p} matches the field of the opposite parity in the previous frame
4782 @item @var{c} matches the field of the opposite parity in the current frame
4783 @item @var{n} matches the field of the opposite parity in the next frame
4788 The @var{u} and @var{b} matching are a bit special in the sense that they match
4789 from the opposite parity flag. In the following examples, we assume that we are
4790 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4791 'x' is placed above and below each matched fields.
4793 With bottom matching (@option{field}=@var{bottom}):
4798 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4799 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4807 With top matching (@option{field}=@var{top}):
4812 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4813 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4821 @subsection Examples
4823 Simple IVTC of a top field first telecined stream:
4825 fieldmatch=order=tff:combmatch=none, decimate
4828 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4830 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4835 Transform the field order of the input video.
4837 It accepts the following parameters:
4842 The output field order. Valid values are @var{tff} for top field first or @var{bff}
4843 for bottom field first.
4846 The default value is @samp{tff}.
4848 The transformation is done by shifting the picture content up or down
4849 by one line, and filling the remaining line with appropriate picture content.
4850 This method is consistent with most broadcast field order converters.
4852 If the input video is not flagged as being interlaced, or it is already
4853 flagged as being of the required output field order, then this filter does
4854 not alter the incoming video.
4856 It is very useful when converting to or from PAL DV material,
4857 which is bottom field first.
4861 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4866 Buffer input images and send them when they are requested.
4868 It is mainly useful when auto-inserted by the libavfilter
4871 It does not take parameters.
4876 Convert the input video to one of the specified pixel formats.
4877 Libavfilter will try to pick one that is suitable as input to
4880 It accepts the following parameters:
4884 A '|'-separated list of pixel format names, such as
4885 "pix_fmts=yuv420p|monow|rgb24".
4889 @subsection Examples
4893 Convert the input video to the @var{yuv420p} format
4895 format=pix_fmts=yuv420p
4898 Convert the input video to any of the formats in the list
4900 format=pix_fmts=yuv420p|yuv444p|yuv410p
4907 Convert the video to specified constant frame rate by duplicating or dropping
4908 frames as necessary.
4910 It accepts the following parameters:
4914 The desired output frame rate. The default is @code{25}.
4919 Possible values are:
4922 zero round towards 0
4926 round towards -infinity
4928 round towards +infinity
4932 The default is @code{near}.
4935 Assume the first PTS should be the given value, in seconds. This allows for
4936 padding/trimming at the start of stream. By default, no assumption is made
4937 about the first frame's expected PTS, so no padding or trimming is done.
4938 For example, this could be set to 0 to pad the beginning with duplicates of
4939 the first frame if a video stream starts after the audio stream or to trim any
4940 frames with a negative PTS.
4944 Alternatively, the options can be specified as a flat string:
4945 @var{fps}[:@var{round}].
4947 See also the @ref{setpts} filter.
4949 @subsection Examples
4953 A typical usage in order to set the fps to 25:
4959 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4961 fps=fps=film:round=near
4967 Pack two different video streams into a stereoscopic video, setting proper
4968 metadata on supported codecs. The two views should have the same size and
4969 framerate and processing will stop when the shorter video ends. Please note
4970 that you may conveniently adjust view properties with the @ref{scale} and
4973 It accepts the following parameters:
4977 The desired packing format. Supported values are:
4982 The views are next to each other (default).
4985 The views are on top of each other.
4988 The views are packed by line.
4991 The views are packed by column.
4994 The views are temporally interleaved.
5003 # Convert left and right views into a frame-sequential video
5004 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
5006 # Convert views into a side-by-side video with the same output resolution as the input
5007 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
5012 Select one frame every N-th frame.
5014 This filter accepts the following option:
5017 Select frame after every @code{step} frames.
5018 Allowed values are positive integers higher than 0. Default value is @code{1}.
5024 Apply a frei0r effect to the input video.
5026 To enable the compilation of this filter, you need to install the frei0r
5027 header and configure FFmpeg with @code{--enable-frei0r}.
5029 It accepts the following parameters:
5034 The name of the frei0r effect to load. If the environment variable
5035 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
5036 directories specified by the colon-separated list in @env{FREIOR_PATH}.
5037 Otherwise, the standard frei0r paths are searched, in this order:
5038 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
5039 @file{/usr/lib/frei0r-1/}.
5042 A '|'-separated list of parameters to pass to the frei0r effect.
5046 A frei0r effect parameter can be a boolean (its value is either
5047 "y" or "n"), a double, a color (specified as
5048 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
5049 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
5050 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
5051 @var{X} and @var{Y} are floating point numbers) and/or a string.
5053 The number and types of parameters depend on the loaded effect. If an
5054 effect parameter is not specified, the default value is set.
5056 @subsection Examples
5060 Apply the distort0r effect, setting the first two double parameters:
5062 frei0r=filter_name=distort0r:filter_params=0.5|0.01
5066 Apply the colordistance effect, taking a color as the first parameter:
5068 frei0r=colordistance:0.2/0.3/0.4
5069 frei0r=colordistance:violet
5070 frei0r=colordistance:0x112233
5074 Apply the perspective effect, specifying the top left and top right image
5077 frei0r=perspective:0.2/0.2|0.8/0.2
5081 For more information, see
5082 @url{http://frei0r.dyne.org}
5086 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
5088 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
5089 processing filter, one of them is performed once per block, not per pixel.
5090 This allows for much higher speed.
5092 The filter accepts the following options:
5096 Set quality. This option defines the number of levels for averaging. It accepts
5097 an integer in the range 4-5. Default value is @code{4}.
5100 Force a constant quantization parameter. It accepts an integer in range 0-63.
5101 If not set, the filter will use the QP from the video stream (if available).
5104 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
5105 more details but also more artifacts, while higher values make the image smoother
5106 but also blurrier. Default value is @code{0} − PSNR optimal.
5109 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
5110 option may cause flicker since the B-Frames have often larger QP. Default is
5111 @code{0} (not enabled).
5117 The filter accepts the following options:
5121 Set the luminance expression.
5123 Set the chrominance blue expression.
5125 Set the chrominance red expression.
5127 Set the alpha expression.
5129 Set the red expression.
5131 Set the green expression.
5133 Set the blue expression.
5136 The colorspace is selected according to the specified options. If one
5137 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
5138 options is specified, the filter will automatically select a YCbCr
5139 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
5140 @option{blue_expr} options is specified, it will select an RGB
5143 If one of the chrominance expression is not defined, it falls back on the other
5144 one. If no alpha expression is specified it will evaluate to opaque value.
5145 If none of chrominance expressions are specified, they will evaluate
5146 to the luminance expression.
5148 The expressions can use the following variables and functions:
5152 The sequential number of the filtered frame, starting from @code{0}.
5156 The coordinates of the current sample.
5160 The width and height of the image.
5164 Width and height scale depending on the currently filtered plane. It is the
5165 ratio between the corresponding luma plane number of pixels and the current
5166 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
5167 @code{0.5,0.5} for chroma planes.
5170 Time of the current frame, expressed in seconds.
5173 Return the value of the pixel at location (@var{x},@var{y}) of the current
5177 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
5181 Return the value of the pixel at location (@var{x},@var{y}) of the
5182 blue-difference chroma plane. Return 0 if there is no such plane.
5185 Return the value of the pixel at location (@var{x},@var{y}) of the
5186 red-difference chroma plane. Return 0 if there is no such plane.
5191 Return the value of the pixel at location (@var{x},@var{y}) of the
5192 red/green/blue component. Return 0 if there is no such component.
5195 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
5196 plane. Return 0 if there is no such plane.
5199 For functions, if @var{x} and @var{y} are outside the area, the value will be
5200 automatically clipped to the closer edge.
5202 @subsection Examples
5206 Flip the image horizontally:
5212 Generate a bidimensional sine wave, with angle @code{PI/3} and a
5213 wavelength of 100 pixels:
5215 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
5219 Generate a fancy enigmatic moving light:
5221 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
5225 Generate a quick emboss effect:
5227 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
5231 Modify RGB components depending on pixel position:
5233 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
5237 Create a radial gradient that is the same size as the input (also see
5238 the @ref{vignette} filter):
5240 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
5244 Create a linear gradient to use as a mask for another filter, then
5245 compose with @ref{overlay}. In this example the video will gradually
5246 become more blurry from the top to the bottom of the y-axis as defined
5247 by the linear gradient:
5249 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
5255 Fix the banding artifacts that are sometimes introduced into nearly flat
5256 regions by truncation to 8bit color depth.
5257 Interpolate the gradients that should go where the bands are, and
5260 It is designed for playback only. Do not use it prior to
5261 lossy compression, because compression tends to lose the dither and
5262 bring back the bands.
5264 It accepts the following parameters:
5269 The maximum amount by which the filter will change any one pixel. This is also
5270 the threshold for detecting nearly flat regions. Acceptable values range from
5271 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
5275 The neighborhood to fit the gradient to. A larger radius makes for smoother
5276 gradients, but also prevents the filter from modifying the pixels near detailed
5277 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
5278 values will be clipped to the valid range.
5282 Alternatively, the options can be specified as a flat string:
5283 @var{strength}[:@var{radius}]
5285 @subsection Examples
5289 Apply the filter with a @code{3.5} strength and radius of @code{8}:
5295 Specify radius, omitting the strength (which will fall-back to the default
5306 Apply a Hald CLUT to a video stream.
5308 First input is the video stream to process, and second one is the Hald CLUT.
5309 The Hald CLUT input can be a simple picture or a complete video stream.
5311 The filter accepts the following options:
5315 Force termination when the shortest input terminates. Default is @code{0}.
5317 Continue applying the last CLUT after the end of the stream. A value of
5318 @code{0} disable the filter after the last frame of the CLUT is reached.
5319 Default is @code{1}.
5322 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
5323 filters share the same internals).
5325 More information about the Hald CLUT can be found on Eskil Steenberg's website
5326 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
5328 @subsection Workflow examples
5330 @subsubsection Hald CLUT video stream
5332 Generate an identity Hald CLUT stream altered with various effects:
5334 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
5337 Note: make sure you use a lossless codec.
5339 Then use it with @code{haldclut} to apply it on some random stream:
5341 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
5344 The Hald CLUT will be applied to the 10 first seconds (duration of
5345 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
5346 to the remaining frames of the @code{mandelbrot} stream.
5348 @subsubsection Hald CLUT with preview
5350 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
5351 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
5352 biggest possible square starting at the top left of the picture. The remaining
5353 padding pixels (bottom or right) will be ignored. This area can be used to add
5354 a preview of the Hald CLUT.
5356 Typically, the following generated Hald CLUT will be supported by the
5357 @code{haldclut} filter:
5360 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
5361 pad=iw+320 [padded_clut];
5362 smptebars=s=320x256, split [a][b];
5363 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
5364 [main][b] overlay=W-320" -frames:v 1 clut.png
5367 It contains the original and a preview of the effect of the CLUT: SMPTE color
5368 bars are displayed on the right-top, and below the same color bars processed by
5371 Then, the effect of this Hald CLUT can be visualized with:
5373 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
5378 Flip the input video horizontally.
5380 For example, to horizontally flip the input video with @command{ffmpeg}:
5382 ffmpeg -i in.avi -vf "hflip" out.avi
5386 This filter applies a global color histogram equalization on a
5389 It can be used to correct video that has a compressed range of pixel
5390 intensities. The filter redistributes the pixel intensities to
5391 equalize their distribution across the intensity range. It may be
5392 viewed as an "automatically adjusting contrast filter". This filter is
5393 useful only for correcting degraded or poorly captured source
5396 The filter accepts the following options:
5400 Determine the amount of equalization to be applied. As the strength
5401 is reduced, the distribution of pixel intensities more-and-more
5402 approaches that of the input frame. The value must be a float number
5403 in the range [0,1] and defaults to 0.200.
5406 Set the maximum intensity that can generated and scale the output
5407 values appropriately. The strength should be set as desired and then
5408 the intensity can be limited if needed to avoid washing-out. The value
5409 must be a float number in the range [0,1] and defaults to 0.210.
5412 Set the antibanding level. If enabled the filter will randomly vary
5413 the luminance of output pixels by a small amount to avoid banding of
5414 the histogram. Possible values are @code{none}, @code{weak} or
5415 @code{strong}. It defaults to @code{none}.
5420 Compute and draw a color distribution histogram for the input video.
5422 The computed histogram is a representation of the color component
5423 distribution in an image.
5425 The filter accepts the following options:
5431 It accepts the following values:
5434 Standard histogram that displays the color components distribution in an
5435 image. Displays color graph for each color component. Shows distribution of
5436 the Y, U, V, A or R, G, B components, depending on input format, in the
5437 current frame. Below each graph a color component scale meter is shown.
5440 Displays chroma values (U/V color placement) in a two dimensional
5441 graph (which is called a vectorscope). The brighter a pixel in the
5442 vectorscope, the more pixels of the input frame correspond to that pixel
5443 (i.e., more pixels have this chroma value). The V component is displayed on
5444 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5445 side being V = 255. The U component is displayed on the vertical (Y) axis,
5446 with the top representing U = 0 and the bottom representing U = 255.
5448 The position of a white pixel in the graph corresponds to the chroma value of
5449 a pixel of the input clip. The graph can therefore be used to read the hue
5450 (color flavor) and the saturation (the dominance of the hue in the color). As
5451 the hue of a color changes, it moves around the square. At the center of the
5452 square the saturation is zero, which means that the corresponding pixel has no
5453 color. If the amount of a specific color is increased (while leaving the other
5454 colors unchanged) the saturation increases, and the indicator moves towards
5455 the edge of the square.
5458 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5462 Per row/column color component graph. In row mode, the graph on the left side
5463 represents color component value 0 and the right side represents value = 255.
5464 In column mode, the top side represents color component value = 0 and bottom
5465 side represents value = 255.
5467 Default value is @code{levels}.
5470 Set height of level in @code{levels}. Default value is @code{200}.
5471 Allowed range is [50, 2048].
5474 Set height of color scale in @code{levels}. Default value is @code{12}.
5475 Allowed range is [0, 40].
5478 Set step for @code{waveform} mode. Smaller values are useful to find out how
5479 many values of the same luminance are distributed across input rows/columns.
5480 Default value is @code{10}. Allowed range is [1, 255].
5483 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5484 Default is @code{row}.
5486 @item waveform_mirror
5487 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5488 means mirrored. In mirrored mode, higher values will be represented on the left
5489 side for @code{row} mode and at the top for @code{column} mode. Default is
5490 @code{0} (unmirrored).
5493 Set display mode for @code{waveform} and @code{levels}.
5494 It accepts the following values:
5497 Display separate graph for the color components side by side in
5498 @code{row} waveform mode or one below the other in @code{column} waveform mode
5499 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5500 per color component graphs are placed below each other.
5502 Using this display mode in @code{waveform} histogram mode makes it easy to
5503 spot color casts in the highlights and shadows of an image, by comparing the
5504 contours of the top and the bottom graphs of each waveform. Since whites,
5505 grays, and blacks are characterized by exactly equal amounts of red, green,
5506 and blue, neutral areas of the picture should display three waveforms of
5507 roughly equal width/height. If not, the correction is easy to perform by
5508 making level adjustments the three waveforms.
5511 Presents information identical to that in the @code{parade}, except
5512 that the graphs representing color components are superimposed directly
5515 This display mode in @code{waveform} histogram mode makes it easier to spot
5516 relative differences or similarities in overlapping areas of the color
5517 components that are supposed to be identical, such as neutral whites, grays,
5520 Default is @code{parade}.
5523 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5524 Default is @code{linear}.
5527 @subsection Examples
5532 Calculate and draw histogram:
5534 ffplay -i input -vf histogram
5542 This is a high precision/quality 3d denoise filter. It aims to reduce
5543 image noise, producing smooth images and making still images really
5544 still. It should enhance compressibility.
5546 It accepts the following optional parameters:
5550 A non-negative floating point number which specifies spatial luma strength.
5553 @item chroma_spatial
5554 A non-negative floating point number which specifies spatial chroma strength.
5555 It defaults to 3.0*@var{luma_spatial}/4.0.
5558 A floating point number which specifies luma temporal strength. It defaults to
5559 6.0*@var{luma_spatial}/4.0.
5562 A floating point number which specifies chroma temporal strength. It defaults to
5563 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5568 Apply a high-quality magnification filter designed for pixel art. This filter
5569 was originally created by Maxim Stepin.
5571 It accepts the following option:
5575 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
5576 @code{hq3x} and @code{4} for @code{hq4x}.
5577 Default is @code{3}.
5582 Modify the hue and/or the saturation of the input.
5584 It accepts the following parameters:
5588 Specify the hue angle as a number of degrees. It accepts an expression,
5589 and defaults to "0".
5592 Specify the saturation in the [-10,10] range. It accepts an expression and
5596 Specify the hue angle as a number of radians. It accepts an
5597 expression, and defaults to "0".
5600 Specify the brightness in the [-10,10] range. It accepts an expression and
5604 @option{h} and @option{H} are mutually exclusive, and can't be
5605 specified at the same time.
5607 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5608 expressions containing the following constants:
5612 frame count of the input frame starting from 0
5615 presentation timestamp of the input frame expressed in time base units
5618 frame rate of the input video, NAN if the input frame rate is unknown
5621 timestamp expressed in seconds, NAN if the input timestamp is unknown
5624 time base of the input video
5627 @subsection Examples
5631 Set the hue to 90 degrees and the saturation to 1.0:
5637 Same command but expressing the hue in radians:
5643 Rotate hue and make the saturation swing between 0
5644 and 2 over a period of 1 second:
5646 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5650 Apply a 3 seconds saturation fade-in effect starting at 0:
5655 The general fade-in expression can be written as:
5657 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5661 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5663 hue="s=max(0\, min(1\, (8-t)/3))"
5666 The general fade-out expression can be written as:
5668 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5673 @subsection Commands
5675 This filter supports the following commands:
5681 Modify the hue and/or the saturation and/or brightness of the input video.
5682 The command accepts the same syntax of the corresponding option.
5684 If the specified expression is not valid, it is kept at its current
5690 Detect video interlacing type.
5692 This filter tries to detect if the input frames as interlaced, progressive,
5693 top or bottom field first. It will also try and detect fields that are
5694 repeated between adjacent frames (a sign of telecine).
5696 Single frame detection considers only immediately adjacent frames when classifying each frame.
5697 Multiple frame detection incorporates the classification history of previous frames.
5699 The filter will log these metadata values:
5702 @item single.current_frame
5703 Detected type of current frame using single-frame detection. One of:
5704 ``tff'' (top field first), ``bff'' (bottom field first),
5705 ``progressive'', or ``undetermined''
5708 Cumulative number of frames detected as top field first using single-frame detection.
5711 Cumulative number of frames detected as top field first using multiple-frame detection.
5714 Cumulative number of frames detected as bottom field first using single-frame detection.
5716 @item multiple.current_frame
5717 Detected type of current frame using multiple-frame detection. One of:
5718 ``tff'' (top field first), ``bff'' (bottom field first),
5719 ``progressive'', or ``undetermined''
5722 Cumulative number of frames detected as bottom field first using multiple-frame detection.
5724 @item single.progressive
5725 Cumulative number of frames detected as progressive using single-frame detection.
5727 @item multiple.progressive
5728 Cumulative number of frames detected as progressive using multiple-frame detection.
5730 @item single.undetermined
5731 Cumulative number of frames that could not be classified using single-frame detection.
5733 @item multiple.undetermined
5734 Cumulative number of frames that could not be classified using multiple-frame detection.
5736 @item repeated.current_frame
5737 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
5739 @item repeated.neither
5740 Cumulative number of frames with no repeated field.
5743 Cumulative number of frames with the top field repeated from the previous frame's top field.
5745 @item repeated.bottom
5746 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
5749 The filter accepts the following options:
5753 Set interlacing threshold.
5755 Set progressive threshold.
5757 Threshold for repeated field detection.
5759 Number of frames after which a given frame's contribution to the
5760 statistics is halved (i.e., it contributes only 0.5 to it's
5761 classification). The default of 0 means that all frames seen are given
5762 full weight of 1.0 forever.
5767 Deinterleave or interleave fields.
5769 This filter allows one to process interlaced images fields without
5770 deinterlacing them. Deinterleaving splits the input frame into 2
5771 fields (so called half pictures). Odd lines are moved to the top
5772 half of the output image, even lines to the bottom half.
5773 You can process (filter) them independently and then re-interleave them.
5775 The filter accepts the following options:
5779 @item chroma_mode, c
5781 Available values for @var{luma_mode}, @var{chroma_mode} and
5782 @var{alpha_mode} are:
5788 @item deinterleave, d
5789 Deinterleave fields, placing one above the other.
5792 Interleave fields. Reverse the effect of deinterleaving.
5794 Default value is @code{none}.
5797 @item chroma_swap, cs
5798 @item alpha_swap, as
5799 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5804 Simple interlacing filter from progressive contents. This interleaves upper (or
5805 lower) lines from odd frames with lower (or upper) lines from even frames,
5806 halving the frame rate and preserving image height.
5809 Original Original New Frame
5810 Frame 'j' Frame 'j+1' (tff)
5811 ========== =========== ==================
5812 Line 0 --------------------> Frame 'j' Line 0
5813 Line 1 Line 1 ----> Frame 'j+1' Line 1
5814 Line 2 ---------------------> Frame 'j' Line 2
5815 Line 3 Line 3 ----> Frame 'j+1' Line 3
5817 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5820 It accepts the following optional parameters:
5824 This determines whether the interlaced frame is taken from the even
5825 (tff - default) or odd (bff) lines of the progressive frame.
5828 Enable (default) or disable the vertical lowpass filter to avoid twitter
5829 interlacing and reduce moire patterns.
5834 Deinterlace input video by applying Donald Graft's adaptive kernel
5835 deinterling. Work on interlaced parts of a video to produce
5838 The description of the accepted parameters follows.
5842 Set the threshold which affects the filter's tolerance when
5843 determining if a pixel line must be processed. It must be an integer
5844 in the range [0,255] and defaults to 10. A value of 0 will result in
5845 applying the process on every pixels.
5848 Paint pixels exceeding the threshold value to white if set to 1.
5852 Set the fields order. Swap fields if set to 1, leave fields alone if
5856 Enable additional sharpening if set to 1. Default is 0.
5859 Enable twoway sharpening if set to 1. Default is 0.
5862 @subsection Examples
5866 Apply default values:
5868 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5872 Enable additional sharpening:
5878 Paint processed pixels in white:
5884 @section lenscorrection
5886 Correct radial lens distortion
5888 This filter can be used to correct for radial distortion as can result from the use
5889 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
5890 one can use tools available for example as part of opencv or simply trial-and-error.
5891 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
5892 and extract the k1 and k2 coefficients from the resulting matrix.
5894 Note that effectively the same filter is available in the open-source tools Krita and
5895 Digikam from the KDE project.
5897 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
5898 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
5899 brightness distribution, so you may want to use both filters together in certain
5900 cases, though you will have to take care of ordering, i.e. whether vignetting should
5901 be applied before or after lens correction.
5905 The filter accepts the following options:
5909 Relative x-coordinate of the focal point of the image, and thereby the center of the
5910 distortion. This value has a range [0,1] and is expressed as fractions of the image
5913 Relative y-coordinate of the focal point of the image, and thereby the center of the
5914 distortion. This value has a range [0,1] and is expressed as fractions of the image
5917 Coefficient of the quadratic correction term. 0.5 means no correction.
5919 Coefficient of the double quadratic correction term. 0.5 means no correction.
5922 The formula that generates the correction is:
5924 @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)
5926 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
5927 distances from the focal point in the source and target images, respectively.
5932 Apply a 3D LUT to an input video.
5934 The filter accepts the following options:
5938 Set the 3D LUT file name.
5940 Currently supported formats:
5952 Select interpolation mode.
5954 Available values are:
5958 Use values from the nearest defined point.
5960 Interpolate values using the 8 points defining a cube.
5962 Interpolate values using a tetrahedron.
5966 @section lut, lutrgb, lutyuv
5968 Compute a look-up table for binding each pixel component input value
5969 to an output value, and apply it to the input video.
5971 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5972 to an RGB input video.
5974 These filters accept the following parameters:
5977 set first pixel component expression
5979 set second pixel component expression
5981 set third pixel component expression
5983 set fourth pixel component expression, corresponds to the alpha component
5986 set red component expression
5988 set green component expression
5990 set blue component expression
5992 alpha component expression
5995 set Y/luminance component expression
5997 set U/Cb component expression
5999 set V/Cr component expression
6002 Each of them specifies the expression to use for computing the lookup table for
6003 the corresponding pixel component values.
6005 The exact component associated to each of the @var{c*} options depends on the
6008 The @var{lut} filter requires either YUV or RGB pixel formats in input,
6009 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
6011 The expressions can contain the following constants and functions:
6016 The input width and height.
6019 The input value for the pixel component.
6022 The input value, clipped to the @var{minval}-@var{maxval} range.
6025 The maximum value for the pixel component.
6028 The minimum value for the pixel component.
6031 The negated value for the pixel component value, clipped to the
6032 @var{minval}-@var{maxval} range; it corresponds to the expression
6033 "maxval-clipval+minval".
6036 The computed value in @var{val}, clipped to the
6037 @var{minval}-@var{maxval} range.
6039 @item gammaval(gamma)
6040 The computed gamma correction value of the pixel component value,
6041 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
6043 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
6047 All expressions default to "val".
6049 @subsection Examples
6055 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
6056 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
6059 The above is the same as:
6061 lutrgb="r=negval:g=negval:b=negval"
6062 lutyuv="y=negval:u=negval:v=negval"
6072 Remove chroma components, turning the video into a graytone image:
6074 lutyuv="u=128:v=128"
6078 Apply a luma burning effect:
6084 Remove green and blue components:
6090 Set a constant alpha channel value on input:
6092 format=rgba,lutrgb=a="maxval-minval/2"
6096 Correct luminance gamma by a factor of 0.5:
6098 lutyuv=y=gammaval(0.5)
6102 Discard least significant bits of luma:
6104 lutyuv=y='bitand(val, 128+64+32)'
6108 @section mergeplanes
6110 Merge color channel components from several video streams.
6112 The filter accepts up to 4 input streams, and merge selected input
6113 planes to the output video.
6115 This filter accepts the following options:
6118 Set input to output plane mapping. Default is @code{0}.
6120 The mappings is specified as a bitmap. It should be specified as a
6121 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
6122 mapping for the first plane of the output stream. 'A' sets the number of
6123 the input stream to use (from 0 to 3), and 'a' the plane number of the
6124 corresponding input to use (from 0 to 3). The rest of the mappings is
6125 similar, 'Bb' describes the mapping for the output stream second
6126 plane, 'Cc' describes the mapping for the output stream third plane and
6127 'Dd' describes the mapping for the output stream fourth plane.
6130 Set output pixel format. Default is @code{yuva444p}.
6133 @subsection Examples
6137 Merge three gray video streams of same width and height into single video stream:
6139 [a0][a1][a2]mergeplanes=0x001020:yuv444p
6143 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
6145 [a0][a1]mergeplanes=0x00010210:yuva444p
6149 Swap Y and A plane in yuva444p stream:
6151 format=yuva444p,mergeplanes=0x03010200:yuva444p
6155 Swap U and V plane in yuv420p stream:
6157 format=yuv420p,mergeplanes=0x000201:yuv420p
6161 Cast a rgb24 clip to yuv444p:
6163 format=rgb24,mergeplanes=0x000102:yuv444p
6169 Apply motion-compensation deinterlacing.
6171 It needs one field per frame as input and must thus be used together
6172 with yadif=1/3 or equivalent.
6174 This filter accepts the following options:
6177 Set the deinterlacing mode.
6179 It accepts one of the following values:
6184 use iterative motion estimation
6186 like @samp{slow}, but use multiple reference frames.
6188 Default value is @samp{fast}.
6191 Set the picture field parity assumed for the input video. It must be
6192 one of the following values:
6196 assume top field first
6198 assume bottom field first
6201 Default value is @samp{bff}.
6204 Set per-block quantization parameter (QP) used by the internal
6207 Higher values should result in a smoother motion vector field but less
6208 optimal individual vectors. Default value is 1.
6213 Apply an MPlayer filter to the input video.
6215 This filter provides a wrapper around some of the filters of
6218 This wrapper is considered experimental. Some of the wrapped filters
6219 may not work properly and we may drop support for them, as they will
6220 be implemented natively into FFmpeg. Thus you should avoid
6221 depending on them when writing portable scripts.
6223 The filter accepts the parameters:
6224 @var{filter_name}[:=]@var{filter_params}
6226 @var{filter_name} is the name of a supported MPlayer filter,
6227 @var{filter_params} is a string containing the parameters accepted by
6230 The list of the currently supported filters follows:
6239 The parameter syntax and behavior for the listed filters are the same
6240 of the corresponding MPlayer filters. For detailed instructions check
6241 the "VIDEO FILTERS" section in the MPlayer manual.
6243 @subsection Examples
6247 Adjust gamma, brightness, contrast:
6253 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
6257 Drop frames that do not differ greatly from the previous frame in
6258 order to reduce frame rate.
6260 The main use of this filter is for very-low-bitrate encoding
6261 (e.g. streaming over dialup modem), but it could in theory be used for
6262 fixing movies that were inverse-telecined incorrectly.
6264 A description of the accepted options follows.
6268 Set the maximum number of consecutive frames which can be dropped (if
6269 positive), or the minimum interval between dropped frames (if
6270 negative). If the value is 0, the frame is dropped unregarding the
6271 number of previous sequentially dropped frames.
6278 Set the dropping threshold values.
6280 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
6281 represent actual pixel value differences, so a threshold of 64
6282 corresponds to 1 unit of difference for each pixel, or the same spread
6283 out differently over the block.
6285 A frame is a candidate for dropping if no 8x8 blocks differ by more
6286 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
6287 meaning the whole image) differ by more than a threshold of @option{lo}.
6289 Default value for @option{hi} is 64*12, default value for @option{lo} is
6290 64*5, and default value for @option{frac} is 0.33.
6298 It accepts an integer in input; if non-zero it negates the
6299 alpha component (if available). The default value in input is 0.
6303 Force libavfilter not to use any of the specified pixel formats for the
6304 input to the next filter.
6306 It accepts the following parameters:
6310 A '|'-separated list of pixel format names, such as
6311 apix_fmts=yuv420p|monow|rgb24".
6315 @subsection Examples
6319 Force libavfilter to use a format different from @var{yuv420p} for the
6320 input to the vflip filter:
6322 noformat=pix_fmts=yuv420p,vflip
6326 Convert the input video to any of the formats not contained in the list:
6328 noformat=yuv420p|yuv444p|yuv410p
6334 Add noise on video input frame.
6336 The filter accepts the following options:
6344 Set noise seed for specific pixel component or all pixel components in case
6345 of @var{all_seed}. Default value is @code{123457}.
6347 @item all_strength, alls
6348 @item c0_strength, c0s
6349 @item c1_strength, c1s
6350 @item c2_strength, c2s
6351 @item c3_strength, c3s
6352 Set noise strength for specific pixel component or all pixel components in case
6353 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
6355 @item all_flags, allf
6360 Set pixel component flags or set flags for all components if @var{all_flags}.
6361 Available values for component flags are:
6364 averaged temporal noise (smoother)
6366 mix random noise with a (semi)regular pattern
6368 temporal noise (noise pattern changes between frames)
6370 uniform noise (gaussian otherwise)
6374 @subsection Examples
6376 Add temporal and uniform noise to input video:
6378 noise=alls=20:allf=t+u
6383 Pass the video source unchanged to the output.
6387 Apply a video transform using libopencv.
6389 To enable this filter, install the libopencv library and headers and
6390 configure FFmpeg with @code{--enable-libopencv}.
6392 It accepts the following parameters:
6397 The name of the libopencv filter to apply.
6400 The parameters to pass to the libopencv filter. If not specified, the default
6405 Refer to the official libopencv documentation for more precise
6407 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
6409 Several libopencv filters are supported; see the following subsections.
6414 Dilate an image by using a specific structuring element.
6415 It corresponds to the libopencv function @code{cvDilate}.
6417 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
6419 @var{struct_el} represents a structuring element, and has the syntax:
6420 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
6422 @var{cols} and @var{rows} represent the number of columns and rows of
6423 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
6424 point, and @var{shape} the shape for the structuring element. @var{shape}
6425 must be "rect", "cross", "ellipse", or "custom".
6427 If the value for @var{shape} is "custom", it must be followed by a
6428 string of the form "=@var{filename}". The file with name
6429 @var{filename} is assumed to represent a binary image, with each
6430 printable character corresponding to a bright pixel. When a custom
6431 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
6432 or columns and rows of the read file are assumed instead.
6434 The default value for @var{struct_el} is "3x3+0x0/rect".
6436 @var{nb_iterations} specifies the number of times the transform is
6437 applied to the image, and defaults to 1.
6441 # Use the default values
6444 # Dilate using a structuring element with a 5x5 cross, iterating two times
6445 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
6447 # Read the shape from the file diamond.shape, iterating two times.
6448 # The file diamond.shape may contain a pattern of characters like this
6454 # The specified columns and rows are ignored
6455 # but the anchor point coordinates are not
6456 ocv=dilate:0x0+2x2/custom=diamond.shape|2
6461 Erode an image by using a specific structuring element.
6462 It corresponds to the libopencv function @code{cvErode}.
6464 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
6465 with the same syntax and semantics as the @ref{dilate} filter.
6469 Smooth the input video.
6471 The filter takes the following parameters:
6472 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
6474 @var{type} is the type of smooth filter to apply, and must be one of
6475 the following values: "blur", "blur_no_scale", "median", "gaussian",
6476 or "bilateral". The default value is "gaussian".
6478 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
6479 depend on the smooth type. @var{param1} and
6480 @var{param2} accept integer positive values or 0. @var{param3} and
6481 @var{param4} accept floating point values.
6483 The default value for @var{param1} is 3. The default value for the
6484 other parameters is 0.
6486 These parameters correspond to the parameters assigned to the
6487 libopencv function @code{cvSmooth}.
6492 Overlay one video on top of another.
6494 It takes two inputs and has one output. The first input is the "main"
6495 video on which the second input is overlaid.
6497 It accepts the following parameters:
6499 A description of the accepted options follows.
6504 Set the expression for the x and y coordinates of the overlaid video
6505 on the main video. Default value is "0" for both expressions. In case
6506 the expression is invalid, it is set to a huge value (meaning that the
6507 overlay will not be displayed within the output visible area).
6510 The action to take when EOF is encountered on the secondary input; it accepts
6511 one of the following values:
6515 Repeat the last frame (the default).
6519 Pass the main input through.
6523 Set when the expressions for @option{x}, and @option{y} are evaluated.
6525 It accepts the following values:
6528 only evaluate expressions once during the filter initialization or
6529 when a command is processed
6532 evaluate expressions for each incoming frame
6535 Default value is @samp{frame}.
6538 If set to 1, force the output to terminate when the shortest input
6539 terminates. Default value is 0.
6542 Set the format for the output video.
6544 It accepts the following values:
6559 Default value is @samp{yuv420}.
6561 @item rgb @emph{(deprecated)}
6562 If set to 1, force the filter to accept inputs in the RGB
6563 color space. Default value is 0. This option is deprecated, use
6564 @option{format} instead.
6567 If set to 1, force the filter to draw the last overlay frame over the
6568 main input until the end of the stream. A value of 0 disables this
6569 behavior. Default value is 1.
6572 The @option{x}, and @option{y} expressions can contain the following
6578 The main input width and height.
6582 The overlay input width and height.
6586 The computed values for @var{x} and @var{y}. They are evaluated for
6591 horizontal and vertical chroma subsample values of the output
6592 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6596 the number of input frame, starting from 0
6599 the position in the file of the input frame, NAN if unknown
6602 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6606 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6607 when evaluation is done @emph{per frame}, and will evaluate to NAN
6608 when @option{eval} is set to @samp{init}.
6610 Be aware that frames are taken from each input video in timestamp
6611 order, hence, if their initial timestamps differ, it is a good idea
6612 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6613 have them begin in the same zero timestamp, as the example for
6614 the @var{movie} filter does.
6616 You can chain together more overlays but you should test the
6617 efficiency of such approach.
6619 @subsection Commands
6621 This filter supports the following commands:
6625 Modify the x and y of the overlay input.
6626 The command accepts the same syntax of the corresponding option.
6628 If the specified expression is not valid, it is kept at its current
6632 @subsection Examples
6636 Draw the overlay at 10 pixels from the bottom right corner of the main
6639 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6642 Using named options the example above becomes:
6644 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6648 Insert a transparent PNG logo in the bottom left corner of the input,
6649 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6651 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6655 Insert 2 different transparent PNG logos (second logo on bottom
6656 right corner) using the @command{ffmpeg} tool:
6658 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
6662 Add a transparent color layer on top of the main video; @code{WxH}
6663 must specify the size of the main input to the overlay filter:
6665 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6669 Play an original video and a filtered version (here with the deshake
6670 filter) side by side using the @command{ffplay} tool:
6672 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6675 The above command is the same as:
6677 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6681 Make a sliding overlay appearing from the left to the right top part of the
6682 screen starting since time 2:
6684 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6688 Compose output by putting two input videos side to side:
6690 ffmpeg -i left.avi -i right.avi -filter_complex "
6691 nullsrc=size=200x100 [background];
6692 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6693 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6694 [background][left] overlay=shortest=1 [background+left];
6695 [background+left][right] overlay=shortest=1:x=100 [left+right]
6700 Mask 10-20 seconds of a video by applying the delogo filter to a section
6702 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6703 -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]'
6708 Chain several overlays in cascade:
6710 nullsrc=s=200x200 [bg];
6711 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6712 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6713 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6714 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6715 [in3] null, [mid2] overlay=100:100 [out0]
6722 Apply Overcomplete Wavelet denoiser.
6724 The filter accepts the following options:
6730 Larger depth values will denoise lower frequency components more, but
6731 slow down filtering.
6733 Must be an int in the range 8-16, default is @code{8}.
6735 @item luma_strength, ls
6738 Must be a double value in the range 0-1000, default is @code{1.0}.
6740 @item chroma_strength, cs
6741 Set chroma strength.
6743 Must be a double value in the range 0-1000, default is @code{1.0}.
6748 Add paddings to the input image, and place the original input at the
6749 provided @var{x}, @var{y} coordinates.
6751 It accepts the following parameters:
6756 Specify an expression for the size of the output image with the
6757 paddings added. If the value for @var{width} or @var{height} is 0, the
6758 corresponding input size is used for the output.
6760 The @var{width} expression can reference the value set by the
6761 @var{height} expression, and vice versa.
6763 The default value of @var{width} and @var{height} is 0.
6767 Specify the offsets to place the input image at within the padded area,
6768 with respect to the top/left border of the output image.
6770 The @var{x} expression can reference the value set by the @var{y}
6771 expression, and vice versa.
6773 The default value of @var{x} and @var{y} is 0.
6776 Specify the color of the padded area. For the syntax of this option,
6777 check the "Color" section in the ffmpeg-utils manual.
6779 The default value of @var{color} is "black".
6782 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6783 options are expressions containing the following constants:
6788 The input video width and height.
6792 These are the same as @var{in_w} and @var{in_h}.
6796 The output width and height (the size of the padded area), as
6797 specified by the @var{width} and @var{height} expressions.
6801 These are the same as @var{out_w} and @var{out_h}.
6805 The x and y offsets as specified by the @var{x} and @var{y}
6806 expressions, or NAN if not yet specified.
6809 same as @var{iw} / @var{ih}
6812 input sample aspect ratio
6815 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6819 The horizontal and vertical chroma subsample values. For example for the
6820 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6823 @subsection Examples
6827 Add paddings with the color "violet" to the input video. The output video
6828 size is 640x480, and the top-left corner of the input video is placed at
6831 pad=640:480:0:40:violet
6834 The example above is equivalent to the following command:
6836 pad=width=640:height=480:x=0:y=40:color=violet
6840 Pad the input to get an output with dimensions increased by 3/2,
6841 and put the input video at the center of the padded area:
6843 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6847 Pad the input to get a squared output with size equal to the maximum
6848 value between the input width and height, and put the input video at
6849 the center of the padded area:
6851 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6855 Pad the input to get a final w/h ratio of 16:9:
6857 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6861 In case of anamorphic video, in order to set the output display aspect
6862 correctly, it is necessary to use @var{sar} in the expression,
6863 according to the relation:
6865 (ih * X / ih) * sar = output_dar
6866 X = output_dar / sar
6869 Thus the previous example needs to be modified to:
6871 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6875 Double the output size and put the input video in the bottom-right
6876 corner of the output padded area:
6878 pad="2*iw:2*ih:ow-iw:oh-ih"
6882 @section perspective
6884 Correct perspective of video not recorded perpendicular to the screen.
6886 A description of the accepted parameters follows.
6897 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6898 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6899 If the @code{sense} option is set to @code{source}, then the specified points will be sent
6900 to the corners of the destination. If the @code{sense} option is set to @code{destination},
6901 then the corners of the source will be sent to the specified coordinates.
6903 The expressions can use the following variables:
6908 the width and height of video frame.
6912 Set interpolation for perspective correction.
6914 It accepts the following values:
6920 Default value is @samp{linear}.
6923 Set interpretation of coordinate options.
6925 It accepts the following values:
6929 Send point in the source specified by the given coordinates to
6930 the corners of the destination.
6932 @item 1, destination
6934 Send the corners of the source to the point in the destination specified
6935 by the given coordinates.
6937 Default value is @samp{source}.
6943 Delay interlaced video by one field time so that the field order changes.
6945 The intended use is to fix PAL movies that have been captured with the
6946 opposite field order to the film-to-video transfer.
6948 A description of the accepted parameters follows.
6954 It accepts the following values:
6957 Capture field order top-first, transfer bottom-first.
6958 Filter will delay the bottom field.
6961 Capture field order bottom-first, transfer top-first.
6962 Filter will delay the top field.
6965 Capture and transfer with the same field order. This mode only exists
6966 for the documentation of the other options to refer to, but if you
6967 actually select it, the filter will faithfully do nothing.
6970 Capture field order determined automatically by field flags, transfer
6972 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6973 basis using field flags. If no field information is available,
6974 then this works just like @samp{u}.
6977 Capture unknown or varying, transfer opposite.
6978 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6979 analyzing the images and selecting the alternative that produces best
6980 match between the fields.
6983 Capture top-first, transfer unknown or varying.
6984 Filter selects among @samp{t} and @samp{p} using image analysis.
6987 Capture bottom-first, transfer unknown or varying.
6988 Filter selects among @samp{b} and @samp{p} using image analysis.
6991 Capture determined by field flags, transfer unknown or varying.
6992 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6993 image analysis. If no field information is available, then this works just
6994 like @samp{U}. This is the default mode.
6997 Both capture and transfer unknown or varying.
6998 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
7002 @section pixdesctest
7004 Pixel format descriptor test filter, mainly useful for internal
7005 testing. The output video should be equal to the input video.
7009 format=monow, pixdesctest
7012 can be used to test the monowhite pixel format descriptor definition.
7016 Enable the specified chain of postprocessing subfilters using libpostproc. This
7017 library should be automatically selected with a GPL build (@code{--enable-gpl}).
7018 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
7019 Each subfilter and some options have a short and a long name that can be used
7020 interchangeably, i.e. dr/dering are the same.
7022 The filters accept the following options:
7026 Set postprocessing subfilters string.
7029 All subfilters share common options to determine their scope:
7033 Honor the quality commands for this subfilter.
7036 Do chrominance filtering, too (default).
7039 Do luminance filtering only (no chrominance).
7042 Do chrominance filtering only (no luminance).
7045 These options can be appended after the subfilter name, separated by a '|'.
7047 Available subfilters are:
7050 @item hb/hdeblock[|difference[|flatness]]
7051 Horizontal deblocking filter
7054 Difference factor where higher values mean more deblocking (default: @code{32}).
7056 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7059 @item vb/vdeblock[|difference[|flatness]]
7060 Vertical deblocking filter
7063 Difference factor where higher values mean more deblocking (default: @code{32}).
7065 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7068 @item ha/hadeblock[|difference[|flatness]]
7069 Accurate horizontal deblocking filter
7072 Difference factor where higher values mean more deblocking (default: @code{32}).
7074 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7077 @item va/vadeblock[|difference[|flatness]]
7078 Accurate vertical deblocking filter
7081 Difference factor where higher values mean more deblocking (default: @code{32}).
7083 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7087 The horizontal and vertical deblocking filters share the difference and
7088 flatness values so you cannot set different horizontal and vertical
7093 Experimental horizontal deblocking filter
7096 Experimental vertical deblocking filter
7101 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
7104 larger -> stronger filtering
7106 larger -> stronger filtering
7108 larger -> stronger filtering
7111 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
7114 Stretch luminance to @code{0-255}.
7117 @item lb/linblenddeint
7118 Linear blend deinterlacing filter that deinterlaces the given block by
7119 filtering all lines with a @code{(1 2 1)} filter.
7121 @item li/linipoldeint
7122 Linear interpolating deinterlacing filter that deinterlaces the given block by
7123 linearly interpolating every second line.
7125 @item ci/cubicipoldeint
7126 Cubic interpolating deinterlacing filter deinterlaces the given block by
7127 cubically interpolating every second line.
7129 @item md/mediandeint
7130 Median deinterlacing filter that deinterlaces the given block by applying a
7131 median filter to every second line.
7133 @item fd/ffmpegdeint
7134 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
7135 second line with a @code{(-1 4 2 4 -1)} filter.
7138 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
7139 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
7141 @item fq/forceQuant[|quantizer]
7142 Overrides the quantizer table from the input with the constant quantizer you
7150 Default pp filter combination (@code{hb|a,vb|a,dr|a})
7153 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
7156 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
7159 @subsection Examples
7163 Apply horizontal and vertical deblocking, deringing and automatic
7164 brightness/contrast:
7170 Apply default filters without brightness/contrast correction:
7176 Apply default filters and temporal denoiser:
7178 pp=default/tmpnoise|1|2|3
7182 Apply deblocking on luminance only, and switch vertical deblocking on or off
7183 automatically depending on available CPU time:
7191 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
7192 Ratio) between two input videos.
7194 This filter takes in input two input videos, the first input is
7195 considered the "main" source and is passed unchanged to the
7196 output. The second input is used as a "reference" video for computing
7199 Both video inputs must have the same resolution and pixel format for
7200 this filter to work correctly. Also it assumes that both inputs
7201 have the same number of frames, which are compared one by one.
7203 The obtained average PSNR is printed through the logging system.
7205 The filter stores the accumulated MSE (mean squared error) of each
7206 frame, and at the end of the processing it is averaged across all frames
7207 equally, and the following formula is applied to obtain the PSNR:
7210 PSNR = 10*log10(MAX^2/MSE)
7213 Where MAX is the average of the maximum values of each component of the
7216 The description of the accepted parameters follows.
7220 If specified the filter will use the named file to save the PSNR of
7221 each individual frame.
7224 The file printed if @var{stats_file} is selected, contains a sequence of
7225 key/value pairs of the form @var{key}:@var{value} for each compared
7228 A description of each shown parameter follows:
7232 sequential number of the input frame, starting from 1
7235 Mean Square Error pixel-by-pixel average difference of the compared
7236 frames, averaged over all the image components.
7238 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
7239 Mean Square Error pixel-by-pixel average difference of the compared
7240 frames for the component specified by the suffix.
7242 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
7243 Peak Signal to Noise ratio of the compared frames for the component
7244 specified by the suffix.
7249 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
7250 [main][ref] psnr="stats_file=stats.log" [out]
7253 On this example the input file being processed is compared with the
7254 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
7255 is stored in @file{stats.log}.
7260 Pulldown reversal (inverse telecine) filter, capable of handling mixed
7261 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
7264 The pullup filter is designed to take advantage of future context in making
7265 its decisions. This filter is stateless in the sense that it does not lock
7266 onto a pattern to follow, but it instead looks forward to the following
7267 fields in order to identify matches and rebuild progressive frames.
7269 To produce content with an even framerate, insert the fps filter after
7270 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
7271 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
7273 The filter accepts the following options:
7280 These options set the amount of "junk" to ignore at the left, right, top, and
7281 bottom of the image, respectively. Left and right are in units of 8 pixels,
7282 while top and bottom are in units of 2 lines.
7283 The default is 8 pixels on each side.
7286 Set the strict breaks. Setting this option to 1 will reduce the chances of
7287 filter generating an occasional mismatched frame, but it may also cause an
7288 excessive number of frames to be dropped during high motion sequences.
7289 Conversely, setting it to -1 will make filter match fields more easily.
7290 This may help processing of video where there is slight blurring between
7291 the fields, but may also cause there to be interlaced frames in the output.
7292 Default value is @code{0}.
7295 Set the metric plane to use. It accepts the following values:
7301 Use chroma blue plane.
7304 Use chroma red plane.
7307 This option may be set to use chroma plane instead of the default luma plane
7308 for doing filter's computations. This may improve accuracy on very clean
7309 source material, but more likely will decrease accuracy, especially if there
7310 is chroma noise (rainbow effect) or any grayscale video.
7311 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
7312 load and make pullup usable in realtime on slow machines.
7315 For best results (without duplicated frames in the output file) it is
7316 necessary to change the output frame rate. For example, to inverse
7317 telecine NTSC input:
7319 ffmpeg -i input -vf pullup -r 24000/1001 ...
7324 Suppress a TV station logo, using an image file to determine which
7325 pixels comprise the logo. It works by filling in the pixels that
7326 comprise the logo with neighboring pixels.
7328 The filter accepts the following options:
7332 Set the filter bitmap file, which can be any image format supported by
7333 libavformat. The width and height of the image file must match those of the
7334 video stream being processed.
7337 Pixels in the provided bitmap image with a value of zero are not
7338 considered part of the logo, non-zero pixels are considered part of
7339 the logo. If you use white (255) for the logo and black (0) for the
7340 rest, you will be safe. For making the filter bitmap, it is
7341 recommended to take a screen capture of a black frame with the logo
7342 visible, and then using a threshold filter followed by the erode
7343 filter once or twice.
7345 If needed, little splotches can be fixed manually. Remember that if
7346 logo pixels are not covered, the filter quality will be much
7347 reduced. Marking too many pixels as part of the logo does not hurt as
7348 much, but it will increase the amount of blurring needed to cover over
7349 the image and will destroy more information than necessary, and extra
7350 pixels will slow things down on a large logo.
7354 Rotate video by an arbitrary angle expressed in radians.
7356 The filter accepts the following options:
7358 A description of the optional parameters follows.
7361 Set an expression for the angle by which to rotate the input video
7362 clockwise, expressed as a number of radians. A negative value will
7363 result in a counter-clockwise rotation. By default it is set to "0".
7365 This expression is evaluated for each frame.
7368 Set the output width expression, default value is "iw".
7369 This expression is evaluated just once during configuration.
7372 Set the output height expression, default value is "ih".
7373 This expression is evaluated just once during configuration.
7376 Enable bilinear interpolation if set to 1, a value of 0 disables
7377 it. Default value is 1.
7380 Set the color used to fill the output area not covered by the rotated
7381 image. For the general syntax of this option, check the "Color" section in the
7382 ffmpeg-utils manual. If the special value "none" is selected then no
7383 background is printed (useful for example if the background is never shown).
7385 Default value is "black".
7388 The expressions for the angle and the output size can contain the
7389 following constants and functions:
7393 sequential number of the input frame, starting from 0. It is always NAN
7394 before the first frame is filtered.
7397 time in seconds of the input frame, it is set to 0 when the filter is
7398 configured. It is always NAN before the first frame is filtered.
7402 horizontal and vertical chroma subsample values. For example for the
7403 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7407 the input video width and height
7411 the output width and height, that is the size of the padded area as
7412 specified by the @var{width} and @var{height} expressions
7416 the minimal width/height required for completely containing the input
7417 video rotated by @var{a} radians.
7419 These are only available when computing the @option{out_w} and
7420 @option{out_h} expressions.
7423 @subsection Examples
7427 Rotate the input by PI/6 radians clockwise:
7433 Rotate the input by PI/6 radians counter-clockwise:
7439 Rotate the input by 45 degrees clockwise:
7445 Apply a constant rotation with period T, starting from an angle of PI/3:
7447 rotate=PI/3+2*PI*t/T
7451 Make the input video rotation oscillating with a period of T
7452 seconds and an amplitude of A radians:
7454 rotate=A*sin(2*PI/T*t)
7458 Rotate the video, output size is chosen so that the whole rotating
7459 input video is always completely contained in the output:
7461 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
7465 Rotate the video, reduce the output size so that no background is ever
7468 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
7472 @subsection Commands
7474 The filter supports the following commands:
7478 Set the angle expression.
7479 The command accepts the same syntax of the corresponding option.
7481 If the specified expression is not valid, it is kept at its current
7487 Apply Shape Adaptive Blur.
7489 The filter accepts the following options:
7492 @item luma_radius, lr
7493 Set luma blur filter strength, must be a value in range 0.1-4.0, default
7494 value is 1.0. A greater value will result in a more blurred image, and
7495 in slower processing.
7497 @item luma_pre_filter_radius, lpfr
7498 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
7501 @item luma_strength, ls
7502 Set luma maximum difference between pixels to still be considered, must
7503 be a value in the 0.1-100.0 range, default value is 1.0.
7505 @item chroma_radius, cr
7506 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
7507 greater value will result in a more blurred image, and in slower
7510 @item chroma_pre_filter_radius, cpfr
7511 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
7513 @item chroma_strength, cs
7514 Set chroma maximum difference between pixels to still be considered,
7515 must be a value in the 0.1-100.0 range.
7518 Each chroma option value, if not explicitly specified, is set to the
7519 corresponding luma option value.
7524 Scale (resize) the input video, using the libswscale library.
7526 The scale filter forces the output display aspect ratio to be the same
7527 of the input, by changing the output sample aspect ratio.
7529 If the input image format is different from the format requested by
7530 the next filter, the scale filter will convert the input to the
7534 The filter accepts the following options, or any of the options
7535 supported by the libswscale scaler.
7537 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
7538 the complete list of scaler options.
7543 Set the output video dimension expression. Default value is the input
7546 If the value is 0, the input width is used for the output.
7548 If one of the values is -1, the scale filter will use a value that
7549 maintains the aspect ratio of the input image, calculated from the
7550 other specified dimension. If both of them are -1, the input size is
7553 If one of the values is -n with n > 1, the scale filter will also use a value
7554 that maintains the aspect ratio of the input image, calculated from the other
7555 specified dimension. After that it will, however, make sure that the calculated
7556 dimension is divisible by n and adjust the value if necessary.
7558 See below for the list of accepted constants for use in the dimension
7562 Set the interlacing mode. It accepts the following values:
7566 Force interlaced aware scaling.
7569 Do not apply interlaced scaling.
7572 Select interlaced aware scaling depending on whether the source frames
7573 are flagged as interlaced or not.
7576 Default value is @samp{0}.
7579 Set libswscale scaling flags. See
7580 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7581 complete list of values. If not explicitly specified the filter applies
7585 Set the video size. For the syntax of this option, check the "Video size"
7586 section in the ffmpeg-utils manual.
7588 @item in_color_matrix
7589 @item out_color_matrix
7590 Set in/output YCbCr color space type.
7592 This allows the autodetected value to be overridden as well as allows forcing
7593 a specific value used for the output and encoder.
7595 If not specified, the color space type depends on the pixel format.
7601 Choose automatically.
7604 Format conforming to International Telecommunication Union (ITU)
7605 Recommendation BT.709.
7608 Set color space conforming to the United States Federal Communications
7609 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7612 Set color space conforming to:
7616 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7619 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7622 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7627 Set color space conforming to SMPTE ST 240:1999.
7632 Set in/output YCbCr sample range.
7634 This allows the autodetected value to be overridden as well as allows forcing
7635 a specific value used for the output and encoder. If not specified, the
7636 range depends on the pixel format. Possible values:
7640 Choose automatically.
7643 Set full range (0-255 in case of 8-bit luma).
7646 Set "MPEG" range (16-235 in case of 8-bit luma).
7649 @item force_original_aspect_ratio
7650 Enable decreasing or increasing output video width or height if necessary to
7651 keep the original aspect ratio. Possible values:
7655 Scale the video as specified and disable this feature.
7658 The output video dimensions will automatically be decreased if needed.
7661 The output video dimensions will automatically be increased if needed.
7665 One useful instance of this option is that when you know a specific device's
7666 maximum allowed resolution, you can use this to limit the output video to
7667 that, while retaining the aspect ratio. For example, device A allows
7668 1280x720 playback, and your video is 1920x800. Using this option (set it to
7669 decrease) and specifying 1280x720 to the command line makes the output
7672 Please note that this is a different thing than specifying -1 for @option{w}
7673 or @option{h}, you still need to specify the output resolution for this option
7678 The values of the @option{w} and @option{h} options are expressions
7679 containing the following constants:
7684 The input width and height
7688 These are the same as @var{in_w} and @var{in_h}.
7692 The output (scaled) width and height
7696 These are the same as @var{out_w} and @var{out_h}
7699 The same as @var{iw} / @var{ih}
7702 input sample aspect ratio
7705 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7709 horizontal and vertical input chroma subsample values. For example for the
7710 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7714 horizontal and vertical output chroma subsample values. For example for the
7715 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7718 @subsection Examples
7722 Scale the input video to a size of 200x100
7727 This is equivalent to:
7738 Specify a size abbreviation for the output size:
7743 which can also be written as:
7749 Scale the input to 2x:
7755 The above is the same as:
7761 Scale the input to 2x with forced interlaced scaling:
7763 scale=2*iw:2*ih:interl=1
7767 Scale the input to half size:
7773 Increase the width, and set the height to the same size:
7786 Increase the height, and set the width to 3/2 of the height:
7788 scale=w=3/2*oh:h=3/5*ih
7792 Increase the size, making the size a multiple of the chroma
7795 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7799 Increase the width to a maximum of 500 pixels,
7800 keeping the same aspect ratio as the input:
7802 scale=w='min(500\, iw*3/2):h=-1'
7806 @section separatefields
7808 The @code{separatefields} takes a frame-based video input and splits
7809 each frame into its components fields, producing a new half height clip
7810 with twice the frame rate and twice the frame count.
7812 This filter use field-dominance information in frame to decide which
7813 of each pair of fields to place first in the output.
7814 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7816 @section setdar, setsar
7818 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7821 This is done by changing the specified Sample (aka Pixel) Aspect
7822 Ratio, according to the following equation:
7824 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7827 Keep in mind that the @code{setdar} filter does not modify the pixel
7828 dimensions of the video frame. Also, the display aspect ratio set by
7829 this filter may be changed by later filters in the filterchain,
7830 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7833 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7834 the filter output video.
7836 Note that as a consequence of the application of this filter, the
7837 output display aspect ratio will change according to the equation
7840 Keep in mind that the sample aspect ratio set by the @code{setsar}
7841 filter may be changed by later filters in the filterchain, e.g. if
7842 another "setsar" or a "setdar" filter is applied.
7844 It accepts the following parameters:
7847 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7848 Set the aspect ratio used by the filter.
7850 The parameter can be a floating point number string, an expression, or
7851 a string of the form @var{num}:@var{den}, where @var{num} and
7852 @var{den} are the numerator and denominator of the aspect ratio. If
7853 the parameter is not specified, it is assumed the value "0".
7854 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7858 Set the maximum integer value to use for expressing numerator and
7859 denominator when reducing the expressed aspect ratio to a rational.
7860 Default value is @code{100}.
7864 The parameter @var{sar} is an expression containing
7865 the following constants:
7869 These are approximated values for the mathematical constants e
7870 (Euler's number), pi (Greek pi), and phi (the golden ratio).
7873 The input width and height.
7876 These are the same as @var{w} / @var{h}.
7879 The input sample aspect ratio.
7882 The input display aspect ratio. It is the same as
7883 (@var{w} / @var{h}) * @var{sar}.
7886 Horizontal and vertical chroma subsample values. For example, for the
7887 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7890 @subsection Examples
7895 To change the display aspect ratio to 16:9, specify one of the following:
7903 To change the sample aspect ratio to 10:11, specify:
7909 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7910 1000 in the aspect ratio reduction, use the command:
7912 setdar=ratio=16/9:max=1000
7920 Force field for the output video frame.
7922 The @code{setfield} filter marks the interlace type field for the
7923 output frames. It does not change the input frame, but only sets the
7924 corresponding property, which affects how the frame is treated by
7925 following filters (e.g. @code{fieldorder} or @code{yadif}).
7927 The filter accepts the following options:
7932 Available values are:
7936 Keep the same field property.
7939 Mark the frame as bottom-field-first.
7942 Mark the frame as top-field-first.
7945 Mark the frame as progressive.
7951 Show a line containing various information for each input video frame.
7952 The input video is not modified.
7954 The shown line contains a sequence of key/value pairs of the form
7955 @var{key}:@var{value}.
7957 The following values are shown in the output:
7961 The (sequential) number of the input frame, starting from 0.
7964 The Presentation TimeStamp of the input frame, expressed as a number of
7965 time base units. The time base unit depends on the filter input pad.
7968 The Presentation TimeStamp of the input frame, expressed as a number of
7972 The position of the frame in the input stream, or -1 if this information is
7973 unavailable and/or meaningless (for example in case of synthetic video).
7976 The pixel format name.
7979 The sample aspect ratio of the input frame, expressed in the form
7980 @var{num}/@var{den}.
7983 The size of the input frame. For the syntax of this option, check the "Video size"
7984 section in the ffmpeg-utils manual.
7987 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
7988 for bottom field first).
7991 This is 1 if the frame is a key frame, 0 otherwise.
7994 The picture type of the input frame ("I" for an I-frame, "P" for a
7995 P-frame, "B" for a B-frame, or "?" for an unknown type).
7996 Also refer to the documentation of the @code{AVPictureType} enum and of
7997 the @code{av_get_picture_type_char} function defined in
7998 @file{libavutil/avutil.h}.
8001 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
8003 @item plane_checksum
8004 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
8005 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
8008 @section shuffleplanes
8010 Reorder and/or duplicate video planes.
8012 It accepts the following parameters:
8017 The index of the input plane to be used as the first output plane.
8020 The index of the input plane to be used as the second output plane.
8023 The index of the input plane to be used as the third output plane.
8026 The index of the input plane to be used as the fourth output plane.
8030 The first plane has the index 0. The default is to keep the input unchanged.
8032 Swap the second and third planes of the input:
8034 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
8037 @section signalstats
8038 Evaluate various visual metrics that assist in determining issues associated
8039 with the digitization of analog video media.
8041 By default the filter will log these metadata values:
8045 Display the minimal Y value contained within the input frame. Expressed in
8049 Display the Y value at the 10% percentile within the input frame. Expressed in
8053 Display the average Y value within the input frame. Expressed in range of
8057 Display the Y value at the 90% percentile within the input frame. Expressed in
8061 Display the maximum Y value contained within the input frame. Expressed in
8065 Display the minimal U value contained within the input frame. Expressed in
8069 Display the U value at the 10% percentile within the input frame. Expressed in
8073 Display the average U value within the input frame. Expressed in range of
8077 Display the U value at the 90% percentile within the input frame. Expressed in
8081 Display the maximum U value contained within the input frame. Expressed in
8085 Display the minimal V value contained within the input frame. Expressed in
8089 Display the V value at the 10% percentile within the input frame. Expressed in
8093 Display the average V value within the input frame. Expressed in range of
8097 Display the V value at the 90% percentile within the input frame. Expressed in
8101 Display the maximum V value contained within the input frame. Expressed in
8105 Display the minimal saturation value contained within the input frame.
8106 Expressed in range of [0-~181.02].
8109 Display the saturation value at the 10% percentile within the input frame.
8110 Expressed in range of [0-~181.02].
8113 Display the average saturation value within the input frame. Expressed in range
8117 Display the saturation value at the 90% percentile within the input frame.
8118 Expressed in range of [0-~181.02].
8121 Display the maximum saturation value contained within the input frame.
8122 Expressed in range of [0-~181.02].
8125 Display the median value for hue within the input frame. Expressed in range of
8129 Display the average value for hue within the input frame. Expressed in range of
8133 Display the average of sample value difference between all values of the Y
8134 plane in the current frame and corresponding values of the previous input frame.
8135 Expressed in range of [0-255].
8138 Display the average of sample value difference between all values of the U
8139 plane in the current frame and corresponding values of the previous input frame.
8140 Expressed in range of [0-255].
8143 Display the average of sample value difference between all values of the V
8144 plane in the current frame and corresponding values of the previous input frame.
8145 Expressed in range of [0-255].
8148 The filter accepts the following options:
8154 @option{stat} specify an additional form of image analysis.
8155 @option{out} output video with the specified type of pixel highlighted.
8157 Both options accept the following values:
8161 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
8162 unlike the neighboring pixels of the same field. Examples of temporal outliers
8163 include the results of video dropouts, head clogs, or tape tracking issues.
8166 Identify @var{vertical line repetition}. Vertical line repetition includes
8167 similar rows of pixels within a frame. In born-digital video vertical line
8168 repetition is common, but this pattern is uncommon in video digitized from an
8169 analog source. When it occurs in video that results from the digitization of an
8170 analog source it can indicate concealment from a dropout compensator.
8173 Identify pixels that fall outside of legal broadcast range.
8177 Set the highlight color for the @option{out} option. The default color is
8181 @subsection Examples
8185 Output data of various video metrics:
8187 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
8191 Output specific data about the minimum and maximum values of the Y plane per frame:
8193 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
8197 Playback video while highlighting pixels that are outside of broadcast range in red.
8199 ffplay example.mov -vf signalstats="out=brng:color=red"
8203 Playback video with signalstats metadata drawn over the frame.
8205 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
8208 The contents of signalstat_drawtext.txt used in the command are:
8211 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
8212 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
8213 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
8214 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
8222 Blur the input video without impacting the outlines.
8224 It accepts the following options:
8227 @item luma_radius, lr
8228 Set the luma radius. The option value must be a float number in
8229 the range [0.1,5.0] that specifies the variance of the gaussian filter
8230 used to blur the image (slower if larger). Default value is 1.0.
8232 @item luma_strength, ls
8233 Set the luma strength. The option value must be a float number
8234 in the range [-1.0,1.0] that configures the blurring. A value included
8235 in [0.0,1.0] will blur the image whereas a value included in
8236 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8238 @item luma_threshold, lt
8239 Set the luma threshold used as a coefficient to determine
8240 whether a pixel should be blurred or not. The option value must be an
8241 integer in the range [-30,30]. A value of 0 will filter all the image,
8242 a value included in [0,30] will filter flat areas and a value included
8243 in [-30,0] will filter edges. Default value is 0.
8245 @item chroma_radius, cr
8246 Set the chroma radius. The option value must be a float number in
8247 the range [0.1,5.0] that specifies the variance of the gaussian filter
8248 used to blur the image (slower if larger). Default value is 1.0.
8250 @item chroma_strength, cs
8251 Set the chroma strength. The option value must be a float number
8252 in the range [-1.0,1.0] that configures the blurring. A value included
8253 in [0.0,1.0] will blur the image whereas a value included in
8254 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8256 @item chroma_threshold, ct
8257 Set the chroma threshold used as a coefficient to determine
8258 whether a pixel should be blurred or not. The option value must be an
8259 integer in the range [-30,30]. A value of 0 will filter all the image,
8260 a value included in [0,30] will filter flat areas and a value included
8261 in [-30,0] will filter edges. Default value is 0.
8264 If a chroma option is not explicitly set, the corresponding luma value
8269 Convert between different stereoscopic image formats.
8271 The filters accept the following options:
8275 Set stereoscopic image format of input.
8277 Available values for input image formats are:
8280 side by side parallel (left eye left, right eye right)
8283 side by side crosseye (right eye left, left eye right)
8286 side by side parallel with half width resolution
8287 (left eye left, right eye right)
8290 side by side crosseye with half width resolution
8291 (right eye left, left eye right)
8294 above-below (left eye above, right eye below)
8297 above-below (right eye above, left eye below)
8300 above-below with half height resolution
8301 (left eye above, right eye below)
8304 above-below with half height resolution
8305 (right eye above, left eye below)
8308 alternating frames (left eye first, right eye second)
8311 alternating frames (right eye first, left eye second)
8313 Default value is @samp{sbsl}.
8317 Set stereoscopic image format of output.
8319 Available values for output image formats are all the input formats as well as:
8322 anaglyph red/blue gray
8323 (red filter on left eye, blue filter on right eye)
8326 anaglyph red/green gray
8327 (red filter on left eye, green filter on right eye)
8330 anaglyph red/cyan gray
8331 (red filter on left eye, cyan filter on right eye)
8334 anaglyph red/cyan half colored
8335 (red filter on left eye, cyan filter on right eye)
8338 anaglyph red/cyan color
8339 (red filter on left eye, cyan filter on right eye)
8342 anaglyph red/cyan color optimized with the least squares projection of dubois
8343 (red filter on left eye, cyan filter on right eye)
8346 anaglyph green/magenta gray
8347 (green filter on left eye, magenta filter on right eye)
8350 anaglyph green/magenta half colored
8351 (green filter on left eye, magenta filter on right eye)
8354 anaglyph green/magenta colored
8355 (green filter on left eye, magenta filter on right eye)
8358 anaglyph green/magenta color optimized with the least squares projection of dubois
8359 (green filter on left eye, magenta filter on right eye)
8362 anaglyph yellow/blue gray
8363 (yellow filter on left eye, blue filter on right eye)
8366 anaglyph yellow/blue half colored
8367 (yellow filter on left eye, blue filter on right eye)
8370 anaglyph yellow/blue colored
8371 (yellow filter on left eye, blue filter on right eye)
8374 anaglyph yellow/blue color optimized with the least squares projection of dubois
8375 (yellow filter on left eye, blue filter on right eye)
8378 interleaved rows (left eye has top row, right eye starts on next row)
8381 interleaved rows (right eye has top row, left eye starts on next row)
8384 mono output (left eye only)
8387 mono output (right eye only)
8390 Default value is @samp{arcd}.
8393 @subsection Examples
8397 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
8403 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
8412 Apply a simple postprocessing filter that compresses and decompresses the image
8413 at several (or - in the case of @option{quality} level @code{6} - all) shifts
8414 and average the results.
8416 The filter accepts the following options:
8420 Set quality. This option defines the number of levels for averaging. It accepts
8421 an integer in the range 0-6. If set to @code{0}, the filter will have no
8422 effect. A value of @code{6} means the higher quality. For each increment of
8423 that value the speed drops by a factor of approximately 2. Default value is
8427 Force a constant quantization parameter. If not set, the filter will use the QP
8428 from the video stream (if available).
8431 Set thresholding mode. Available modes are:
8435 Set hard thresholding (default).
8437 Set soft thresholding (better de-ringing effect, but likely blurrier).
8441 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8442 option may cause flicker since the B-Frames have often larger QP. Default is
8443 @code{0} (not enabled).
8449 Draw subtitles on top of input video using the libass library.
8451 To enable compilation of this filter you need to configure FFmpeg with
8452 @code{--enable-libass}. This filter also requires a build with libavcodec and
8453 libavformat to convert the passed subtitles file to ASS (Advanced Substation
8454 Alpha) subtitles format.
8456 The filter accepts the following options:
8460 Set the filename of the subtitle file to read. It must be specified.
8463 Specify the size of the original video, the video for which the ASS file
8464 was composed. For the syntax of this option, check the "Video size" section in
8465 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
8466 this is necessary to correctly scale the fonts if the aspect ratio has been
8470 Set subtitles input character encoding. @code{subtitles} filter only. Only
8471 useful if not UTF-8.
8473 @item stream_index, si
8474 Set subtitles stream index. @code{subtitles} filter only.
8477 If the first key is not specified, it is assumed that the first value
8478 specifies the @option{filename}.
8480 For example, to render the file @file{sub.srt} on top of the input
8481 video, use the command:
8486 which is equivalent to:
8488 subtitles=filename=sub.srt
8491 To render the default subtitles stream from file @file{video.mkv}, use:
8496 To render the second subtitles stream from that file, use:
8498 subtitles=video.mkv:si=1
8503 Scale the input by 2x and smooth using the Super2xSaI (Scale and
8504 Interpolate) pixel art scaling algorithm.
8506 Useful for enlarging pixel art images without reducing sharpness.
8513 Apply telecine process to the video.
8515 This filter accepts the following options:
8524 The default value is @code{top}.
8528 A string of numbers representing the pulldown pattern you wish to apply.
8529 The default value is @code{23}.
8533 Some typical patterns:
8538 24p: 2332 (preferred)
8545 24p: 222222222223 ("Euro pulldown")
8551 Select the most representative frame in a given sequence of consecutive frames.
8553 The filter accepts the following options:
8557 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
8558 will pick one of them, and then handle the next batch of @var{n} frames until
8559 the end. Default is @code{100}.
8562 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
8563 value will result in a higher memory usage, so a high value is not recommended.
8565 @subsection Examples
8569 Extract one picture each 50 frames:
8575 Complete example of a thumbnail creation with @command{ffmpeg}:
8577 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
8583 Tile several successive frames together.
8585 The filter accepts the following options:
8590 Set the grid size (i.e. the number of lines and columns). For the syntax of
8591 this option, check the "Video size" section in the ffmpeg-utils manual.
8594 Set the maximum number of frames to render in the given area. It must be less
8595 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
8596 the area will be used.
8599 Set the outer border margin in pixels.
8602 Set the inner border thickness (i.e. the number of pixels between frames). For
8603 more advanced padding options (such as having different values for the edges),
8604 refer to the pad video filter.
8607 Specify the color of the unused area. For the syntax of this option, check the
8608 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
8612 @subsection Examples
8616 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
8618 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
8620 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
8621 duplicating each output frame to accommodate the originally detected frame
8625 Display @code{5} pictures in an area of @code{3x2} frames,
8626 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
8627 mixed flat and named options:
8629 tile=3x2:nb_frames=5:padding=7:margin=2
8635 Perform various types of temporal field interlacing.
8637 Frames are counted starting from 1, so the first input frame is
8640 The filter accepts the following options:
8645 Specify the mode of the interlacing. This option can also be specified
8646 as a value alone. See below for a list of values for this option.
8648 Available values are:
8652 Move odd frames into the upper field, even into the lower field,
8653 generating a double height frame 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
8676 Only output even frames, odd frames are dropped, generating a frame with
8677 unchanged height at half frame rate.
8682 Frame 1 Frame 2 Frame 3 Frame 4
8684 11111 22222 33333 44444
8685 11111 22222 33333 44444
8686 11111 22222 33333 44444
8687 11111 22222 33333 44444
8697 Only output odd frames, even frames are dropped, generating a frame with
8698 unchanged height at half frame rate.
8703 Frame 1 Frame 2 Frame 3 Frame 4
8705 11111 22222 33333 44444
8706 11111 22222 33333 44444
8707 11111 22222 33333 44444
8708 11111 22222 33333 44444
8718 Expand each frame to full height, but pad alternate lines with black,
8719 generating a frame with double height at the same input frame rate.
8724 Frame 1 Frame 2 Frame 3 Frame 4
8726 11111 22222 33333 44444
8727 11111 22222 33333 44444
8728 11111 22222 33333 44444
8729 11111 22222 33333 44444
8732 11111 ..... 33333 .....
8733 ..... 22222 ..... 44444
8734 11111 ..... 33333 .....
8735 ..... 22222 ..... 44444
8736 11111 ..... 33333 .....
8737 ..... 22222 ..... 44444
8738 11111 ..... 33333 .....
8739 ..... 22222 ..... 44444
8743 @item interleave_top, 4
8744 Interleave the upper field from odd frames with the lower field from
8745 even frames, generating a frame with unchanged height at half frame rate.
8750 Frame 1 Frame 2 Frame 3 Frame 4
8752 11111<- 22222 33333<- 44444
8753 11111 22222<- 33333 44444<-
8754 11111<- 22222 33333<- 44444
8755 11111 22222<- 33333 44444<-
8765 @item interleave_bottom, 5
8766 Interleave the lower field from odd frames with the upper field from
8767 even frames, generating a frame with unchanged height at half frame rate.
8772 Frame 1 Frame 2 Frame 3 Frame 4
8774 11111 22222<- 33333 44444<-
8775 11111<- 22222 33333<- 44444
8776 11111 22222<- 33333 44444<-
8777 11111<- 22222 33333<- 44444
8787 @item interlacex2, 6
8788 Double frame rate with unchanged height. Frames are inserted each
8789 containing the second temporal field from the previous input frame and
8790 the first temporal field from the next input frame. This mode relies on
8791 the top_field_first flag. Useful for interlaced video displays with no
8792 field synchronisation.
8797 Frame 1 Frame 2 Frame 3 Frame 4
8799 11111 22222 33333 44444
8800 11111 22222 33333 44444
8801 11111 22222 33333 44444
8802 11111 22222 33333 44444
8805 11111 22222 22222 33333 33333 44444 44444
8806 11111 11111 22222 22222 33333 33333 44444
8807 11111 22222 22222 33333 33333 44444 44444
8808 11111 11111 22222 22222 33333 33333 44444
8814 Numeric values are deprecated but are accepted for backward
8815 compatibility reasons.
8817 Default mode is @code{merge}.
8820 Specify flags influencing the filter process.
8822 Available value for @var{flags} is:
8825 @item low_pass_filter, vlfp
8826 Enable vertical low-pass filtering in the filter.
8827 Vertical low-pass filtering is required when creating an interlaced
8828 destination from a progressive source which contains high-frequency
8829 vertical detail. Filtering will reduce interlace 'twitter' and Moire
8832 Vertical low-pass filtering can only be enabled for @option{mode}
8833 @var{interleave_top} and @var{interleave_bottom}.
8840 Transpose rows with columns in the input video and optionally flip it.
8842 It accepts the following parameters:
8847 Specify the transposition direction.
8849 Can assume the following values:
8851 @item 0, 4, cclock_flip
8852 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
8860 Rotate by 90 degrees clockwise, that is:
8868 Rotate by 90 degrees counterclockwise, that is:
8875 @item 3, 7, clock_flip
8876 Rotate by 90 degrees clockwise and vertically flip, that is:
8884 For values between 4-7, the transposition is only done if the input
8885 video geometry is portrait and not landscape. These values are
8886 deprecated, the @code{passthrough} option should be used instead.
8888 Numerical values are deprecated, and should be dropped in favor of
8892 Do not apply the transposition if the input geometry matches the one
8893 specified by the specified value. It accepts the following values:
8896 Always apply transposition.
8898 Preserve portrait geometry (when @var{height} >= @var{width}).
8900 Preserve landscape geometry (when @var{width} >= @var{height}).
8903 Default value is @code{none}.
8906 For example to rotate by 90 degrees clockwise and preserve portrait
8909 transpose=dir=1:passthrough=portrait
8912 The command above can also be specified as:
8914 transpose=1:portrait
8918 Trim the input so that the output contains one continuous subpart of the input.
8920 It accepts the following parameters:
8923 Specify the time of the start of the kept section, i.e. the frame with the
8924 timestamp @var{start} will be the first frame in the output.
8927 Specify the time of the first frame that will be dropped, i.e. the frame
8928 immediately preceding the one with the timestamp @var{end} will be the last
8929 frame in the output.
8932 This is the same as @var{start}, except this option sets the start timestamp
8933 in timebase units instead of seconds.
8936 This is the same as @var{end}, except this option sets the end timestamp
8937 in timebase units instead of seconds.
8940 The maximum duration of the output in seconds.
8943 The number of the first frame that should be passed to the output.
8946 The number of the first frame that should be dropped.
8949 @option{start}, @option{end}, and @option{duration} are expressed as time
8950 duration specifications; see
8951 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
8952 for the accepted syntax.
8954 Note that the first two sets of the start/end options and the @option{duration}
8955 option look at the frame timestamp, while the _frame variants simply count the
8956 frames that pass through the filter. Also note that this filter does not modify
8957 the timestamps. If you wish for the output timestamps to start at zero, insert a
8958 setpts filter after the trim filter.
8960 If multiple start or end options are set, this filter tries to be greedy and
8961 keep all the frames that match at least one of the specified constraints. To keep
8962 only the part that matches all the constraints at once, chain multiple trim
8965 The defaults are such that all the input is kept. So it is possible to set e.g.
8966 just the end values to keep everything before the specified time.
8971 Drop everything except the second minute of input:
8973 ffmpeg -i INPUT -vf trim=60:120
8977 Keep only the first second:
8979 ffmpeg -i INPUT -vf trim=duration=1
8988 Sharpen or blur the input video.
8990 It accepts the following parameters:
8993 @item luma_msize_x, lx
8994 Set the luma matrix horizontal size. It must be an odd integer between
8995 3 and 63. The default value is 5.
8997 @item luma_msize_y, ly
8998 Set the luma matrix vertical size. It must be an odd integer between 3
8999 and 63. The default value is 5.
9001 @item luma_amount, la
9002 Set the luma effect strength. It must be a floating point number, reasonable
9003 values lay between -1.5 and 1.5.
9005 Negative values will blur the input video, while positive values will
9006 sharpen it, a value of zero will disable the effect.
9008 Default value is 1.0.
9010 @item chroma_msize_x, cx
9011 Set the chroma matrix horizontal size. It must be an odd integer
9012 between 3 and 63. The default value is 5.
9014 @item chroma_msize_y, cy
9015 Set the chroma matrix vertical size. It must be an odd integer
9016 between 3 and 63. The default value is 5.
9018 @item chroma_amount, ca
9019 Set the chroma effect strength. It must be a floating point number, reasonable
9020 values lay between -1.5 and 1.5.
9022 Negative values will blur the input video, while positive values will
9023 sharpen it, a value of zero will disable the effect.
9025 Default value is 0.0.
9028 If set to 1, specify using OpenCL capabilities, only available if
9029 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
9033 All parameters are optional and default to the equivalent of the
9034 string '5:5:1.0:5:5:0.0'.
9036 @subsection Examples
9040 Apply strong luma sharpen effect:
9042 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
9046 Apply a strong blur of both luma and chroma parameters:
9048 unsharp=7:7:-2:7:7:-2
9054 Apply ultra slow/simple postprocessing filter that compresses and decompresses
9055 the image at several (or - in the case of @option{quality} level @code{8} - all)
9056 shifts and average the results.
9058 The way this differs from the behavior of spp is that uspp actually encodes &
9059 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
9060 DCT similar to MJPEG.
9062 The filter accepts the following options:
9066 Set quality. This option defines the number of levels for averaging. It accepts
9067 an integer in the range 0-8. If set to @code{0}, the filter will have no
9068 effect. A value of @code{8} means the higher quality. For each increment of
9069 that value the speed drops by a factor of approximately 2. Default value is
9073 Force a constant quantization parameter. If not set, the filter will use the QP
9074 from the video stream (if available).
9077 @anchor{vidstabdetect}
9078 @section vidstabdetect
9080 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
9081 @ref{vidstabtransform} for pass 2.
9083 This filter generates a file with relative translation and rotation
9084 transform information about subsequent frames, which is then used by
9085 the @ref{vidstabtransform} filter.
9087 To enable compilation of this filter you need to configure FFmpeg with
9088 @code{--enable-libvidstab}.
9090 This filter accepts the following options:
9094 Set the path to the file used to write the transforms information.
9095 Default value is @file{transforms.trf}.
9098 Set how shaky the video is and how quick the camera is. It accepts an
9099 integer in the range 1-10, a value of 1 means little shakiness, a
9100 value of 10 means strong shakiness. Default value is 5.
9103 Set the accuracy of the detection process. It must be a value in the
9104 range 1-15. A value of 1 means low accuracy, a value of 15 means high
9105 accuracy. Default value is 15.
9108 Set stepsize of the search process. The region around minimum is
9109 scanned with 1 pixel resolution. Default value is 6.
9112 Set minimum contrast. Below this value a local measurement field is
9113 discarded. Must be a floating point value in the range 0-1. Default
9117 Set reference frame number for tripod mode.
9119 If enabled, the motion of the frames is compared to a reference frame
9120 in the filtered stream, identified by the specified number. The idea
9121 is to compensate all movements in a more-or-less static scene and keep
9122 the camera view absolutely still.
9124 If set to 0, it is disabled. The frames are counted starting from 1.
9127 Show fields and transforms in the resulting frames. It accepts an
9128 integer in the range 0-2. Default value is 0, which disables any
9132 @subsection Examples
9142 Analyze strongly shaky movie and put the results in file
9143 @file{mytransforms.trf}:
9145 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
9149 Visualize the result of internal transformations in the resulting
9152 vidstabdetect=show=1
9156 Analyze a video with medium shakiness using @command{ffmpeg}:
9158 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
9162 @anchor{vidstabtransform}
9163 @section vidstabtransform
9165 Video stabilization/deshaking: pass 2 of 2,
9166 see @ref{vidstabdetect} for pass 1.
9168 Read a file with transform information for each frame and
9169 apply/compensate them. Together with the @ref{vidstabdetect}
9170 filter this can be used to deshake videos. See also
9171 @url{http://public.hronopik.de/vid.stab}. It is important to also use
9172 the @ref{unsharp} filter, see below.
9174 To enable compilation of this filter you need to configure FFmpeg with
9175 @code{--enable-libvidstab}.
9181 Set path to the file used to read the transforms. Default value is
9182 @file{transforms.trf}.
9185 Set the number of frames (value*2 + 1) used for lowpass filtering the
9186 camera movements. Default value is 10.
9188 For example a number of 10 means that 21 frames are used (10 in the
9189 past and 10 in the future) to smoothen the motion in the video. A
9190 larger value leads to a smoother video, but limits the acceleration of
9191 the camera (pan/tilt movements). 0 is a special case where a static
9192 camera is simulated.
9195 Set the camera path optimization algorithm.
9197 Accepted values are:
9200 gaussian kernel low-pass filter on camera motion (default)
9202 averaging on transformations
9206 Set maximal number of pixels to translate frames. Default value is -1,
9210 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
9211 value is -1, meaning no limit.
9214 Specify how to deal with borders that may be visible due to movement
9217 Available values are:
9220 keep image information from previous frame (default)
9222 fill the border black
9226 Invert transforms if set to 1. Default value is 0.
9229 Consider transforms as relative to previous frame if set to 1,
9230 absolute if set to 0. Default value is 0.
9233 Set percentage to zoom. A positive value will result in a zoom-in
9234 effect, a negative value in a zoom-out effect. Default value is 0 (no
9238 Set optimal zooming to avoid borders.
9240 Accepted values are:
9245 optimal static zoom value is determined (only very strong movements
9246 will lead to visible borders) (default)
9248 optimal adaptive zoom value is determined (no borders will be
9249 visible), see @option{zoomspeed}
9252 Note that the value given at zoom is added to the one calculated here.
9255 Set percent to zoom maximally each frame (enabled when
9256 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
9260 Specify type of interpolation.
9262 Available values are:
9267 linear only horizontal
9269 linear in both directions (default)
9271 cubic in both directions (slow)
9275 Enable virtual tripod mode if set to 1, which is equivalent to
9276 @code{relative=0:smoothing=0}. Default value is 0.
9278 Use also @code{tripod} option of @ref{vidstabdetect}.
9281 Increase log verbosity if set to 1. Also the detected global motions
9282 are written to the temporary file @file{global_motions.trf}. Default
9286 @subsection Examples
9290 Use @command{ffmpeg} for a typical stabilization with default values:
9292 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
9295 Note the use of the @ref{unsharp} filter which is always recommended.
9298 Zoom in a bit more and load transform data from a given file:
9300 vidstabtransform=zoom=5:input="mytransforms.trf"
9304 Smoothen the video even more:
9306 vidstabtransform=smoothing=30
9312 Flip the input video vertically.
9314 For example, to vertically flip a video with @command{ffmpeg}:
9316 ffmpeg -i in.avi -vf "vflip" out.avi
9322 Make or reverse a natural vignetting effect.
9324 The filter accepts the following options:
9328 Set lens angle expression as a number of radians.
9330 The value is clipped in the @code{[0,PI/2]} range.
9332 Default value: @code{"PI/5"}
9336 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
9340 Set forward/backward mode.
9342 Available modes are:
9345 The larger the distance from the central point, the darker the image becomes.
9348 The larger the distance from the central point, the brighter the image becomes.
9349 This can be used to reverse a vignette effect, though there is no automatic
9350 detection to extract the lens @option{angle} and other settings (yet). It can
9351 also be used to create a burning effect.
9354 Default value is @samp{forward}.
9357 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
9359 It accepts the following values:
9362 Evaluate expressions only once during the filter initialization.
9365 Evaluate expressions for each incoming frame. This is way slower than the
9366 @samp{init} mode since it requires all the scalers to be re-computed, but it
9367 allows advanced dynamic expressions.
9370 Default value is @samp{init}.
9373 Set dithering to reduce the circular banding effects. Default is @code{1}
9377 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
9378 Setting this value to the SAR of the input will make a rectangular vignetting
9379 following the dimensions of the video.
9381 Default is @code{1/1}.
9384 @subsection Expressions
9386 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
9387 following parameters.
9392 input width and height
9395 the number of input frame, starting from 0
9398 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
9399 @var{TB} units, NAN if undefined
9402 frame rate of the input video, NAN if the input frame rate is unknown
9405 the PTS (Presentation TimeStamp) of the filtered video frame,
9406 expressed in seconds, NAN if undefined
9409 time base of the input video
9413 @subsection Examples
9417 Apply simple strong vignetting effect:
9423 Make a flickering vignetting:
9425 vignette='PI/4+random(1)*PI/50':eval=frame
9432 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
9433 Deinterlacing Filter").
9435 Based on the process described by Martin Weston for BBC R&D, and
9436 implemented based on the de-interlace algorithm written by Jim
9437 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
9438 uses filter coefficients calculated by BBC R&D.
9440 There are two sets of filter coefficients, so called "simple":
9441 and "complex". Which set of filter coefficients is used can
9442 be set by passing an optional parameter:
9446 Set the interlacing filter coefficients. Accepts one of the following values:
9450 Simple filter coefficient set.
9452 More-complex filter coefficient set.
9454 Default value is @samp{complex}.
9457 Specify which frames to deinterlace. Accept one of the following values:
9461 Deinterlace all frames,
9463 Only deinterlace frames marked as interlaced.
9466 Default value is @samp{all}.
9470 Apply the xBR high-quality magnification filter which is designed for pixel
9471 art. It follows a set of edge-detection rules, see
9472 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
9474 It accepts the following option:
9478 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
9479 @code{3xBR} and @code{4} for @code{4xBR}.
9480 Default is @code{3}.
9486 Deinterlace the input video ("yadif" means "yet another deinterlacing
9489 It accepts the following parameters:
9495 The interlacing mode to adopt. It accepts one of the following values:
9499 Output one frame for each frame.
9501 Output one frame for each field.
9502 @item 2, send_frame_nospatial
9503 Like @code{send_frame}, but it skips the spatial interlacing check.
9504 @item 3, send_field_nospatial
9505 Like @code{send_field}, but it skips the spatial interlacing check.
9508 The default value is @code{send_frame}.
9511 The picture field parity assumed for the input interlaced video. It accepts one
9512 of the following values:
9516 Assume the top field is first.
9518 Assume the bottom field is first.
9520 Enable automatic detection of field parity.
9523 The default value is @code{auto}.
9524 If the interlacing is unknown or the decoder does not export this information,
9525 top field first will be assumed.
9528 Specify which frames to deinterlace. Accept one of the following
9533 Deinterlace all frames.
9535 Only deinterlace frames marked as interlaced.
9538 The default value is @code{all}.
9543 Apply Zoom & Pan effect.
9545 This filter accepts the following options:
9549 Set the zoom expression. Default is 1.
9553 Set the x and y expression. Default is 0.
9556 Set the duration expression in number of frames.
9557 This sets for how many number of frames effect will last for
9561 Set the output image size, default is 'hd720'.
9564 Each expression can contain the following constants:
9587 Last calculated 'x' and 'y' position from 'x' and 'y' expression
9588 for current input frame.
9592 'x' and 'y' of last output frame of previous input frame or 0 when there was
9593 not yet such frame (first input frame).
9596 Last calculated zoom from 'z' expression for current input frame.
9599 Last calculated zoom of last output frame of previous input frame.
9602 Number of output frames for current input frame. Calculated from 'd' expression
9603 for each input frame.
9606 number of output frames created for previous input frame
9609 Rational number: input width / input height
9615 display aspect ratio
9619 @subsection Examples
9623 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
9625 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
9629 @c man end VIDEO FILTERS
9631 @chapter Video Sources
9632 @c man begin VIDEO SOURCES
9634 Below is a description of the currently available video sources.
9638 Buffer video frames, and make them available to the filter chain.
9640 This source is mainly intended for a programmatic use, in particular
9641 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
9643 It accepts the following parameters:
9648 Specify the size (width and height) of the buffered video frames. For the
9649 syntax of this option, check the "Video size" section in the ffmpeg-utils
9653 The input video width.
9656 The input video height.
9659 A string representing the pixel format of the buffered video frames.
9660 It may be a number corresponding to a pixel format, or a pixel format
9664 Specify the timebase assumed by the timestamps of the buffered frames.
9667 Specify the frame rate expected for the video stream.
9669 @item pixel_aspect, sar
9670 The sample (pixel) aspect ratio of the input video.
9673 Specify the optional parameters to be used for the scale filter which
9674 is automatically inserted when an input change is detected in the
9675 input size or format.
9680 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
9683 will instruct the source to accept video frames with size 320x240 and
9684 with format "yuv410p", assuming 1/24 as the timestamps timebase and
9685 square pixels (1:1 sample aspect ratio).
9686 Since the pixel format with name "yuv410p" corresponds to the number 6
9687 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
9688 this example corresponds to:
9690 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
9693 Alternatively, the options can be specified as a flat string, but this
9694 syntax is deprecated:
9696 @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}]
9700 Create a pattern generated by an elementary cellular automaton.
9702 The initial state of the cellular automaton can be defined through the
9703 @option{filename}, and @option{pattern} options. If such options are
9704 not specified an initial state is created randomly.
9706 At each new frame a new row in the video is filled with the result of
9707 the cellular automaton next generation. The behavior when the whole
9708 frame is filled is defined by the @option{scroll} option.
9710 This source accepts the following options:
9714 Read the initial cellular automaton state, i.e. the starting row, from
9716 In the file, each non-whitespace character is considered an alive
9717 cell, a newline will terminate the row, and further characters in the
9718 file will be ignored.
9721 Read the initial cellular automaton state, i.e. the starting row, from
9722 the specified string.
9724 Each non-whitespace character in the string is considered an alive
9725 cell, a newline will terminate the row, and further characters in the
9726 string will be ignored.
9729 Set the video rate, that is the number of frames generated per second.
9732 @item random_fill_ratio, ratio
9733 Set the random fill ratio for the initial cellular automaton row. It
9734 is a floating point number value ranging from 0 to 1, defaults to
9737 This option is ignored when a file or a pattern is specified.
9739 @item random_seed, seed
9740 Set the seed for filling randomly the initial row, must be an integer
9741 included between 0 and UINT32_MAX. If not specified, or if explicitly
9742 set to -1, the filter will try to use a good random seed on a best
9746 Set the cellular automaton rule, it is a number ranging from 0 to 255.
9747 Default value is 110.
9750 Set the size of the output video. For the syntax of this option, check
9751 the "Video size" section in the ffmpeg-utils manual.
9753 If @option{filename} or @option{pattern} is specified, the size is set
9754 by default to the width of the specified initial state row, and the
9755 height is set to @var{width} * PHI.
9757 If @option{size} is set, it must contain the width of the specified
9758 pattern string, and the specified pattern will be centered in the
9761 If a filename or a pattern string is not specified, the size value
9762 defaults to "320x518" (used for a randomly generated initial state).
9765 If set to 1, scroll the output upward when all the rows in the output
9766 have been already filled. If set to 0, the new generated row will be
9767 written over the top row just after the bottom row is filled.
9770 @item start_full, full
9771 If set to 1, completely fill the output with generated rows before
9772 outputting the first frame.
9773 This is the default behavior, for disabling set the value to 0.
9776 If set to 1, stitch the left and right row edges together.
9777 This is the default behavior, for disabling set the value to 0.
9780 @subsection Examples
9784 Read the initial state from @file{pattern}, and specify an output of
9787 cellauto=f=pattern:s=200x400
9791 Generate a random initial row with a width of 200 cells, with a fill
9794 cellauto=ratio=2/3:s=200x200
9798 Create a pattern generated by rule 18 starting by a single alive cell
9799 centered on an initial row with width 100:
9801 cellauto=p=@@:s=100x400:full=0:rule=18
9805 Specify a more elaborated initial pattern:
9807 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
9814 Generate a Mandelbrot set fractal, and progressively zoom towards the
9815 point specified with @var{start_x} and @var{start_y}.
9817 This source accepts the following options:
9822 Set the terminal pts value. Default value is 400.
9825 Set the terminal scale value.
9826 Must be a floating point value. Default value is 0.3.
9829 Set the inner coloring mode, that is the algorithm used to draw the
9830 Mandelbrot fractal internal region.
9832 It shall assume one of the following values:
9837 Show time until convergence.
9839 Set color based on point closest to the origin of the iterations.
9844 Default value is @var{mincol}.
9847 Set the bailout value. Default value is 10.0.
9850 Set the maximum of iterations performed by the rendering
9851 algorithm. Default value is 7189.
9854 Set outer coloring mode.
9855 It shall assume one of following values:
9857 @item iteration_count
9858 Set iteration cound mode.
9859 @item normalized_iteration_count
9860 set normalized iteration count mode.
9862 Default value is @var{normalized_iteration_count}.
9865 Set frame rate, expressed as number of frames per second. Default
9869 Set frame size. For the syntax of this option, check the "Video
9870 size" section in the ffmpeg-utils manual. Default value is "640x480".
9873 Set the initial scale value. Default value is 3.0.
9876 Set the initial x position. Must be a floating point value between
9877 -100 and 100. Default value is -0.743643887037158704752191506114774.
9880 Set the initial y position. Must be a floating point value between
9881 -100 and 100. Default value is -0.131825904205311970493132056385139.
9886 Generate various test patterns, as generated by the MPlayer test filter.
9888 The size of the generated video is fixed, and is 256x256.
9889 This source is useful in particular for testing encoding features.
9891 This source accepts the following options:
9896 Specify the frame rate of the sourced video, as the number of frames
9897 generated per second. It has to be a string in the format
9898 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9899 number or a valid video frame rate abbreviation. The default value is
9903 Set the duration of the sourced video. See
9904 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
9905 for the accepted syntax.
9907 If not specified, or the expressed duration is negative, the video is
9908 supposed to be generated forever.
9912 Set the number or the name of the test to perform. Supported tests are:
9928 Default value is "all", which will cycle through the list of all tests.
9936 will generate a "dc_luma" test pattern.
9940 Provide a frei0r source.
9942 To enable compilation of this filter you need to install the frei0r
9943 header and configure FFmpeg with @code{--enable-frei0r}.
9945 This source accepts the following parameters:
9950 The size of the video to generate. For the syntax of this option, check the
9951 "Video size" section in the ffmpeg-utils manual.
9954 The framerate of the generated video. It may be a string of the form
9955 @var{num}/@var{den} or a frame rate abbreviation.
9958 The name to the frei0r source to load. For more information regarding frei0r and
9959 how to set the parameters, read the @ref{frei0r} section in the video filters
9963 A '|'-separated list of parameters to pass to the frei0r source.
9967 For example, to generate a frei0r partik0l source with size 200x200
9968 and frame rate 10 which is overlaid on the overlay filter main input:
9970 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
9975 Generate a life pattern.
9977 This source is based on a generalization of John Conway's life game.
9979 The sourced input represents a life grid, each pixel represents a cell
9980 which can be in one of two possible states, alive or dead. Every cell
9981 interacts with its eight neighbours, which are the cells that are
9982 horizontally, vertically, or diagonally adjacent.
9984 At each interaction the grid evolves according to the adopted rule,
9985 which specifies the number of neighbor alive cells which will make a
9986 cell stay alive or born. The @option{rule} option allows one to specify
9989 This source accepts the following options:
9993 Set the file from which to read the initial grid state. In the file,
9994 each non-whitespace character is considered an alive cell, and newline
9995 is used to delimit the end of each row.
9997 If this option is not specified, the initial grid is generated
10001 Set the video rate, that is the number of frames generated per second.
10004 @item random_fill_ratio, ratio
10005 Set the random fill ratio for the initial random grid. It is a
10006 floating point number value ranging from 0 to 1, defaults to 1/PHI.
10007 It is ignored when a file is specified.
10009 @item random_seed, seed
10010 Set the seed for filling the initial random grid, must be an integer
10011 included between 0 and UINT32_MAX. If not specified, or if explicitly
10012 set to -1, the filter will try to use a good random seed on a best
10018 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
10019 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
10020 @var{NS} specifies the number of alive neighbor cells which make a
10021 live cell stay alive, and @var{NB} the number of alive neighbor cells
10022 which make a dead cell to become alive (i.e. to "born").
10023 "s" and "b" can be used in place of "S" and "B", respectively.
10025 Alternatively a rule can be specified by an 18-bits integer. The 9
10026 high order bits are used to encode the next cell state if it is alive
10027 for each number of neighbor alive cells, the low order bits specify
10028 the rule for "borning" new cells. Higher order bits encode for an
10029 higher number of neighbor cells.
10030 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
10031 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
10033 Default value is "S23/B3", which is the original Conway's game of life
10034 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
10035 cells, and will born a new cell if there are three alive cells around
10039 Set the size of the output video. For the syntax of this option, check the
10040 "Video size" section in the ffmpeg-utils manual.
10042 If @option{filename} is specified, the size is set by default to the
10043 same size of the input file. If @option{size} is set, it must contain
10044 the size specified in the input file, and the initial grid defined in
10045 that file is centered in the larger resulting area.
10047 If a filename is not specified, the size value defaults to "320x240"
10048 (used for a randomly generated initial grid).
10051 If set to 1, stitch the left and right grid edges together, and the
10052 top and bottom edges also. Defaults to 1.
10055 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
10056 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
10057 value from 0 to 255.
10060 Set the color of living (or new born) cells.
10063 Set the color of dead cells. If @option{mold} is set, this is the first color
10064 used to represent a dead cell.
10067 Set mold color, for definitely dead and moldy cells.
10069 For the syntax of these 3 color options, check the "Color" section in the
10070 ffmpeg-utils manual.
10073 @subsection Examples
10077 Read a grid from @file{pattern}, and center it on a grid of size
10080 life=f=pattern:s=300x300
10084 Generate a random grid of size 200x200, with a fill ratio of 2/3:
10086 life=ratio=2/3:s=200x200
10090 Specify a custom rule for evolving a randomly generated grid:
10096 Full example with slow death effect (mold) using @command{ffplay}:
10098 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
10103 @anchor{haldclutsrc}
10105 @anchor{rgbtestsrc}
10107 @anchor{smptehdbars}
10109 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
10111 The @code{color} source provides an uniformly colored input.
10113 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
10114 @ref{haldclut} filter.
10116 The @code{nullsrc} source returns unprocessed video frames. It is
10117 mainly useful to be employed in analysis / debugging tools, or as the
10118 source for filters which ignore the input data.
10120 The @code{rgbtestsrc} source generates an RGB test pattern useful for
10121 detecting RGB vs BGR issues. You should see a red, green and blue
10122 stripe from top to bottom.
10124 The @code{smptebars} source generates a color bars pattern, based on
10125 the SMPTE Engineering Guideline EG 1-1990.
10127 The @code{smptehdbars} source generates a color bars pattern, based on
10128 the SMPTE RP 219-2002.
10130 The @code{testsrc} source generates a test video pattern, showing a
10131 color pattern, a scrolling gradient and a timestamp. This is mainly
10132 intended for testing purposes.
10134 The sources accept the following parameters:
10139 Specify the color of the source, only available in the @code{color}
10140 source. For the syntax of this option, check the "Color" section in the
10141 ffmpeg-utils manual.
10144 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
10145 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
10146 pixels to be used as identity matrix for 3D lookup tables. Each component is
10147 coded on a @code{1/(N*N)} scale.
10150 Specify the size of the sourced video. For the syntax of this option, check the
10151 "Video size" section in the ffmpeg-utils manual. The default value is
10154 This option is not available with the @code{haldclutsrc} filter.
10157 Specify the frame rate of the sourced video, as the number of frames
10158 generated per second. It has to be a string in the format
10159 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
10160 number or a valid video frame rate abbreviation. The default value is
10164 Set the sample aspect ratio of the sourced video.
10167 Set the duration of the sourced video. See
10168 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
10169 for the accepted syntax.
10171 If not specified, or the expressed duration is negative, the video is
10172 supposed to be generated forever.
10175 Set the number of decimals to show in the timestamp, only available in the
10176 @code{testsrc} source.
10178 The displayed timestamp value will correspond to the original
10179 timestamp value multiplied by the power of 10 of the specified
10180 value. Default value is 0.
10183 For example the following:
10185 testsrc=duration=5.3:size=qcif:rate=10
10188 will generate a video with a duration of 5.3 seconds, with size
10189 176x144 and a frame rate of 10 frames per second.
10191 The following graph description will generate a red source
10192 with an opacity of 0.2, with size "qcif" and a frame rate of 10
10195 color=c=red@@0.2:s=qcif:r=10
10198 If the input content is to be ignored, @code{nullsrc} can be used. The
10199 following command generates noise in the luminance plane by employing
10200 the @code{geq} filter:
10202 nullsrc=s=256x256, geq=random(1)*255:128:128
10205 @subsection Commands
10207 The @code{color} source supports the following commands:
10211 Set the color of the created image. Accepts the same syntax of the
10212 corresponding @option{color} option.
10215 @c man end VIDEO SOURCES
10217 @chapter Video Sinks
10218 @c man begin VIDEO SINKS
10220 Below is a description of the currently available video sinks.
10222 @section buffersink
10224 Buffer video frames, and make them available to the end of the filter
10227 This sink is mainly intended for programmatic use, in particular
10228 through the interface defined in @file{libavfilter/buffersink.h}
10229 or the options system.
10231 It accepts a pointer to an AVBufferSinkContext structure, which
10232 defines the incoming buffers' formats, to be passed as the opaque
10233 parameter to @code{avfilter_init_filter} for initialization.
10237 Null video sink: do absolutely nothing with the input video. It is
10238 mainly useful as a template and for use in analysis / debugging
10241 @c man end VIDEO SINKS
10243 @chapter Multimedia Filters
10244 @c man begin MULTIMEDIA FILTERS
10246 Below is a description of the currently available multimedia filters.
10248 @section avectorscope
10250 Convert input audio to a video output, representing the audio vector
10253 The filter is used to measure the difference between channels of stereo
10254 audio stream. A monoaural signal, consisting of identical left and right
10255 signal, results in straight vertical line. Any stereo separation is visible
10256 as a deviation from this line, creating a Lissajous figure.
10257 If the straight (or deviation from it) but horizontal line appears this
10258 indicates that the left and right channels are out of phase.
10260 The filter accepts the following options:
10264 Set the vectorscope mode.
10266 Available values are:
10269 Lissajous rotated by 45 degrees.
10272 Same as above but not rotated.
10275 Default value is @samp{lissajous}.
10278 Set the video size for the output. For the syntax of this option, check the "Video size"
10279 section in the ffmpeg-utils manual. Default value is @code{400x400}.
10282 Set the output frame rate. Default value is @code{25}.
10287 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
10288 Allowed range is @code{[0, 255]}.
10293 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
10294 Allowed range is @code{[0, 255]}.
10297 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
10300 @subsection Examples
10304 Complete example using @command{ffplay}:
10306 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10307 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
10313 Concatenate audio and video streams, joining them together one after the
10316 The filter works on segments of synchronized video and audio streams. All
10317 segments must have the same number of streams of each type, and that will
10318 also be the number of streams at output.
10320 The filter accepts the following options:
10325 Set the number of segments. Default is 2.
10328 Set the number of output video streams, that is also the number of video
10329 streams in each segment. Default is 1.
10332 Set the number of output audio streams, that is also the number of audio
10333 streams in each segment. Default is 0.
10336 Activate unsafe mode: do not fail if segments have a different format.
10340 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
10341 @var{a} audio outputs.
10343 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
10344 segment, in the same order as the outputs, then the inputs for the second
10347 Related streams do not always have exactly the same duration, for various
10348 reasons including codec frame size or sloppy authoring. For that reason,
10349 related synchronized streams (e.g. a video and its audio track) should be
10350 concatenated at once. The concat filter will use the duration of the longest
10351 stream in each segment (except the last one), and if necessary pad shorter
10352 audio streams with silence.
10354 For this filter to work correctly, all segments must start at timestamp 0.
10356 All corresponding streams must have the same parameters in all segments; the
10357 filtering system will automatically select a common pixel format for video
10358 streams, and a common sample format, sample rate and channel layout for
10359 audio streams, but other settings, such as resolution, must be converted
10360 explicitly by the user.
10362 Different frame rates are acceptable but will result in variable frame rate
10363 at output; be sure to configure the output file to handle it.
10365 @subsection Examples
10369 Concatenate an opening, an episode and an ending, all in bilingual version
10370 (video in stream 0, audio in streams 1 and 2):
10372 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
10373 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
10374 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
10375 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
10379 Concatenate two parts, handling audio and video separately, using the
10380 (a)movie sources, and adjusting the resolution:
10382 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
10383 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
10384 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
10386 Note that a desync will happen at the stitch if the audio and video streams
10387 do not have exactly the same duration in the first file.
10393 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
10394 it unchanged. By default, it logs a message at a frequency of 10Hz with the
10395 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
10396 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
10398 The filter also has a video output (see the @var{video} option) with a real
10399 time graph to observe the loudness evolution. The graphic contains the logged
10400 message mentioned above, so it is not printed anymore when this option is set,
10401 unless the verbose logging is set. The main graphing area contains the
10402 short-term loudness (3 seconds of analysis), and the gauge on the right is for
10403 the momentary loudness (400 milliseconds).
10405 More information about the Loudness Recommendation EBU R128 on
10406 @url{http://tech.ebu.ch/loudness}.
10408 The filter accepts the following options:
10413 Activate the video output. The audio stream is passed unchanged whether this
10414 option is set or no. The video stream will be the first output stream if
10415 activated. Default is @code{0}.
10418 Set the video size. This option is for video only. For the syntax of this
10419 option, check the "Video size" section in the ffmpeg-utils manual. Default
10420 and minimum resolution is @code{640x480}.
10423 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
10424 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
10425 other integer value between this range is allowed.
10428 Set metadata injection. If set to @code{1}, the audio input will be segmented
10429 into 100ms output frames, each of them containing various loudness information
10430 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
10432 Default is @code{0}.
10435 Force the frame logging level.
10437 Available values are:
10440 information logging level
10442 verbose logging level
10445 By default, the logging level is set to @var{info}. If the @option{video} or
10446 the @option{metadata} options are set, it switches to @var{verbose}.
10451 Available modes can be cumulated (the option is a @code{flag} type). Possible
10455 Disable any peak mode (default).
10457 Enable sample-peak mode.
10459 Simple peak mode looking for the higher sample value. It logs a message
10460 for sample-peak (identified by @code{SPK}).
10462 Enable true-peak mode.
10464 If enabled, the peak lookup is done on an over-sampled version of the input
10465 stream for better peak accuracy. It logs a message for true-peak.
10466 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
10467 This mode requires a build with @code{libswresample}.
10472 @subsection Examples
10476 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
10478 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
10482 Run an analysis with @command{ffmpeg}:
10484 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
10488 @section interleave, ainterleave
10490 Temporally interleave frames from several inputs.
10492 @code{interleave} works with video inputs, @code{ainterleave} with audio.
10494 These filters read frames from several inputs and send the oldest
10495 queued frame to the output.
10497 Input streams must have a well defined, monotonically increasing frame
10500 In order to submit one frame to output, these filters need to enqueue
10501 at least one frame for each input, so they cannot work in case one
10502 input is not yet terminated and will not receive incoming frames.
10504 For example consider the case when one input is a @code{select} filter
10505 which always drop input frames. The @code{interleave} filter will keep
10506 reading from that input, but it will never be able to send new frames
10507 to output until the input will send an end-of-stream signal.
10509 Also, depending on inputs synchronization, the filters will drop
10510 frames in case one input receives more frames than the other ones, and
10511 the queue is already filled.
10513 These filters accept the following options:
10517 Set the number of different inputs, it is 2 by default.
10520 @subsection Examples
10524 Interleave frames belonging to different streams using @command{ffmpeg}:
10526 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
10530 Add flickering blur effect:
10532 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
10536 @section perms, aperms
10538 Set read/write permissions for the output frames.
10540 These filters are mainly aimed at developers to test direct path in the
10541 following filter in the filtergraph.
10543 The filters accept the following options:
10547 Select the permissions mode.
10549 It accepts the following values:
10552 Do nothing. This is the default.
10554 Set all the output frames read-only.
10556 Set all the output frames directly writable.
10558 Make the frame read-only if writable, and writable if read-only.
10560 Set each output frame read-only or writable randomly.
10564 Set the seed for the @var{random} mode, must be an integer included between
10565 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
10566 @code{-1}, the filter will try to use a good random seed on a best effort
10570 Note: in case of auto-inserted filter between the permission filter and the
10571 following one, the permission might not be received as expected in that
10572 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
10573 perms/aperms filter can avoid this problem.
10575 @section select, aselect
10577 Select frames to pass in output.
10579 This filter accepts the following options:
10584 Set expression, which is evaluated for each input frame.
10586 If the expression is evaluated to zero, the frame is discarded.
10588 If the evaluation result is negative or NaN, the frame is sent to the
10589 first output; otherwise it is sent to the output with index
10590 @code{ceil(val)-1}, assuming that the input index starts from 0.
10592 For example a value of @code{1.2} corresponds to the output with index
10593 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
10596 Set the number of outputs. The output to which to send the selected
10597 frame is based on the result of the evaluation. Default value is 1.
10600 The expression can contain the following constants:
10604 The (sequential) number of the filtered frame, starting from 0.
10607 The (sequential) number of the selected frame, starting from 0.
10609 @item prev_selected_n
10610 The sequential number of the last selected frame. It's NAN if undefined.
10613 The timebase of the input timestamps.
10616 The PTS (Presentation TimeStamp) of the filtered video frame,
10617 expressed in @var{TB} units. It's NAN if undefined.
10620 The PTS of the filtered video frame,
10621 expressed in seconds. It's NAN if undefined.
10624 The PTS of the previously filtered video frame. It's NAN if undefined.
10626 @item prev_selected_pts
10627 The PTS of the last previously filtered video frame. It's NAN if undefined.
10629 @item prev_selected_t
10630 The PTS of the last previously selected video frame. It's NAN if undefined.
10633 The PTS of the first video frame in the video. It's NAN if undefined.
10636 The time of the first video frame in the video. It's NAN if undefined.
10638 @item pict_type @emph{(video only)}
10639 The type of the filtered frame. It can assume one of the following
10651 @item interlace_type @emph{(video only)}
10652 The frame interlace type. It can assume one of the following values:
10655 The frame is progressive (not interlaced).
10657 The frame is top-field-first.
10659 The frame is bottom-field-first.
10662 @item consumed_sample_n @emph{(audio only)}
10663 the number of selected samples before the current frame
10665 @item samples_n @emph{(audio only)}
10666 the number of samples in the current frame
10668 @item sample_rate @emph{(audio only)}
10669 the input sample rate
10672 This is 1 if the filtered frame is a key-frame, 0 otherwise.
10675 the position in the file of the filtered frame, -1 if the information
10676 is not available (e.g. for synthetic video)
10678 @item scene @emph{(video only)}
10679 value between 0 and 1 to indicate a new scene; a low value reflects a low
10680 probability for the current frame to introduce a new scene, while a higher
10681 value means the current frame is more likely to be one (see the example below)
10685 The default value of the select expression is "1".
10687 @subsection Examples
10691 Select all frames in input:
10696 The example above is the same as:
10708 Select only I-frames:
10710 select='eq(pict_type\,I)'
10714 Select one frame every 100:
10716 select='not(mod(n\,100))'
10720 Select only frames contained in the 10-20 time interval:
10722 select=between(t\,10\,20)
10726 Select only I frames contained in the 10-20 time interval:
10728 select=between(t\,10\,20)*eq(pict_type\,I)
10732 Select frames with a minimum distance of 10 seconds:
10734 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
10738 Use aselect to select only audio frames with samples number > 100:
10740 aselect='gt(samples_n\,100)'
10744 Create a mosaic of the first scenes:
10746 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
10749 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
10753 Send even and odd frames to separate outputs, and compose them:
10755 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
10759 @section sendcmd, asendcmd
10761 Send commands to filters in the filtergraph.
10763 These filters read commands to be sent to other filters in the
10766 @code{sendcmd} must be inserted between two video filters,
10767 @code{asendcmd} must be inserted between two audio filters, but apart
10768 from that they act the same way.
10770 The specification of commands can be provided in the filter arguments
10771 with the @var{commands} option, or in a file specified by the
10772 @var{filename} option.
10774 These filters accept the following options:
10777 Set the commands to be read and sent to the other filters.
10779 Set the filename of the commands to be read and sent to the other
10783 @subsection Commands syntax
10785 A commands description consists of a sequence of interval
10786 specifications, comprising a list of commands to be executed when a
10787 particular event related to that interval occurs. The occurring event
10788 is typically the current frame time entering or leaving a given time
10791 An interval is specified by the following syntax:
10793 @var{START}[-@var{END}] @var{COMMANDS};
10796 The time interval is specified by the @var{START} and @var{END} times.
10797 @var{END} is optional and defaults to the maximum time.
10799 The current frame time is considered within the specified interval if
10800 it is included in the interval [@var{START}, @var{END}), that is when
10801 the time is greater or equal to @var{START} and is lesser than
10804 @var{COMMANDS} consists of a sequence of one or more command
10805 specifications, separated by ",", relating to that interval. The
10806 syntax of a command specification is given by:
10808 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
10811 @var{FLAGS} is optional and specifies the type of events relating to
10812 the time interval which enable sending the specified command, and must
10813 be a non-null sequence of identifier flags separated by "+" or "|" and
10814 enclosed between "[" and "]".
10816 The following flags are recognized:
10819 The command is sent when the current frame timestamp enters the
10820 specified interval. In other words, the command is sent when the
10821 previous frame timestamp was not in the given interval, and the
10825 The command is sent when the current frame timestamp leaves the
10826 specified interval. In other words, the command is sent when the
10827 previous frame timestamp was in the given interval, and the
10831 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
10834 @var{TARGET} specifies the target of the command, usually the name of
10835 the filter class or a specific filter instance name.
10837 @var{COMMAND} specifies the name of the command for the target filter.
10839 @var{ARG} is optional and specifies the optional list of argument for
10840 the given @var{COMMAND}.
10842 Between one interval specification and another, whitespaces, or
10843 sequences of characters starting with @code{#} until the end of line,
10844 are ignored and can be used to annotate comments.
10846 A simplified BNF description of the commands specification syntax
10849 @var{COMMAND_FLAG} ::= "enter" | "leave"
10850 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
10851 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
10852 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
10853 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
10854 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
10857 @subsection Examples
10861 Specify audio tempo change at second 4:
10863 asendcmd=c='4.0 atempo tempo 1.5',atempo
10867 Specify a list of drawtext and hue commands in a file.
10869 # show text in the interval 5-10
10870 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
10871 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
10873 # desaturate the image in the interval 15-20
10874 15.0-20.0 [enter] hue s 0,
10875 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
10877 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
10879 # apply an exponential saturation fade-out effect, starting from time 25
10880 25 [enter] hue s exp(25-t)
10883 A filtergraph allowing to read and process the above command list
10884 stored in a file @file{test.cmd}, can be specified with:
10886 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
10891 @section setpts, asetpts
10893 Change the PTS (presentation timestamp) of the input frames.
10895 @code{setpts} works on video frames, @code{asetpts} on audio frames.
10897 This filter accepts the following options:
10902 The expression which is evaluated for each frame to construct its timestamp.
10906 The expression is evaluated through the eval API and can contain the following
10911 frame rate, only defined for constant frame-rate video
10914 The presentation timestamp in input
10917 The count of the input frame for video or the number of consumed samples,
10918 not including the current frame for audio, starting from 0.
10920 @item NB_CONSUMED_SAMPLES
10921 The number of consumed samples, not including the current frame (only
10924 @item NB_SAMPLES, S
10925 The number of samples in the current frame (only audio)
10927 @item SAMPLE_RATE, SR
10928 The audio sample rate.
10931 The PTS of the first frame.
10934 the time in seconds of the first frame
10937 State whether the current frame is interlaced.
10940 the time in seconds of the current frame
10943 original position in the file of the frame, or undefined if undefined
10944 for the current frame
10947 The previous input PTS.
10950 previous input time in seconds
10953 The previous output PTS.
10956 previous output time in seconds
10959 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
10963 The wallclock (RTC) time at the start of the movie in microseconds.
10966 The timebase of the input timestamps.
10970 @subsection Examples
10974 Start counting PTS from zero
10976 setpts=PTS-STARTPTS
10980 Apply fast motion effect:
10986 Apply slow motion effect:
10992 Set fixed rate of 25 frames per second:
10998 Set fixed rate 25 fps with some jitter:
11000 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
11004 Apply an offset of 10 seconds to the input PTS:
11010 Generate timestamps from a "live source" and rebase onto the current timebase:
11012 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
11016 Generate timestamps by counting samples:
11023 @section settb, asettb
11025 Set the timebase to use for the output frames timestamps.
11026 It is mainly useful for testing timebase configuration.
11028 It accepts the following parameters:
11033 The expression which is evaluated into the output timebase.
11037 The value for @option{tb} is an arithmetic expression representing a
11038 rational. The expression can contain the constants "AVTB" (the default
11039 timebase), "intb" (the input timebase) and "sr" (the sample rate,
11040 audio only). Default value is "intb".
11042 @subsection Examples
11046 Set the timebase to 1/25:
11052 Set the timebase to 1/10:
11058 Set the timebase to 1001/1000:
11064 Set the timebase to 2*intb:
11070 Set the default timebase value:
11077 Convert input audio to a video output representing
11078 frequency spectrum logarithmically (using constant Q transform with
11079 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
11081 The filter accepts the following options:
11085 Specify transform volume (multiplier) expression. The expression can contain
11088 @item frequency, freq, f
11089 the frequency where transform is evaluated
11090 @item timeclamp, tc
11091 value of timeclamp option
11095 @item a_weighting(f)
11096 A-weighting of equal loudness
11097 @item b_weighting(f)
11098 B-weighting of equal loudness
11099 @item c_weighting(f)
11100 C-weighting of equal loudness
11102 Default value is @code{16}.
11105 Specify transform length expression. The expression can contain variables:
11107 @item frequency, freq, f
11108 the frequency where transform is evaluated
11109 @item timeclamp, tc
11110 value of timeclamp option
11112 Default value is @code{384/f*tc/(384/f+tc)}.
11115 Specify the transform timeclamp. At low frequency, there is trade-off between
11116 accuracy in time domain and frequency domain. If timeclamp is lower,
11117 event in time domain is represented more accurately (such as fast bass drum),
11118 otherwise event in frequency domain is represented more accurately
11119 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
11122 Specify the transform coeffclamp. If coeffclamp is lower, transform is
11123 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
11124 Default value is @code{1.0}.
11127 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
11128 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
11129 Default value is @code{3.0}.
11132 Specify font file for use with freetype. If not specified, use embedded font.
11135 Specify font color expression. This is arithmetic expression that should return
11136 integer value 0xRRGGBB. The expression can contain variables:
11138 @item frequency, freq, f
11139 the frequency where transform is evaluated
11140 @item timeclamp, tc
11141 value of timeclamp option
11146 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
11147 @item r(x), g(x), b(x)
11148 red, green, and blue value of intensity x
11150 Default value is @code{st(0, (midi(f)-59.5)/12);
11151 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
11152 r(1-ld(1)) + b(ld(1))}
11155 If set to 1 (the default), the video size is 1920x1080 (full HD),
11156 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
11159 Specify video fps. Default value is @code{25}.
11162 Specify number of transform per frame, so there are fps*count transforms
11163 per second. Note that audio data rate must be divisible by fps*count.
11164 Default value is @code{6}.
11168 @subsection Examples
11172 Playing audio while showing the spectrum:
11174 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
11178 Same as above, but with frame rate 30 fps:
11180 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
11184 Playing at 960x540 and lower CPU usage:
11186 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
11190 A1 and its harmonics: A1, A2, (near)E3, A3:
11192 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),
11193 asplit[a][out1]; [a] showcqt [out0]'
11197 Same as above, but with more accuracy in frequency domain (and slower):
11199 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),
11200 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
11204 B-weighting of equal loudness
11206 volume=16*b_weighting(f)
11212 tlength=100/f*tc/(100/f+tc)
11216 Custom fontcolor, C-note is colored green, others are colored blue
11218 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))'
11223 @section showspectrum
11225 Convert input audio to a video output, representing the audio frequency
11228 The filter accepts the following options:
11232 Specify the video size for the output. For the syntax of this option, check
11233 the "Video size" section in the ffmpeg-utils manual. Default value is
11237 Specify how the spectrum should slide along the window.
11239 It accepts the following values:
11242 the samples start again on the left when they reach the right
11244 the samples scroll from right to left
11246 frames are only produced when the samples reach the right
11249 Default value is @code{replace}.
11252 Specify display mode.
11254 It accepts the following values:
11257 all channels are displayed in the same row
11259 all channels are displayed in separate rows
11262 Default value is @samp{combined}.
11265 Specify display color mode.
11267 It accepts the following values:
11270 each channel is displayed in a separate color
11272 each channel is is displayed using the same color scheme
11275 Default value is @samp{channel}.
11278 Specify scale used for calculating intensity color values.
11280 It accepts the following values:
11285 square root, default
11292 Default value is @samp{sqrt}.
11295 Set saturation modifier for displayed colors. Negative values provide
11296 alternative color scheme. @code{0} is no saturation at all.
11297 Saturation must be in [-10.0, 10.0] range.
11298 Default value is @code{1}.
11301 Set window function.
11303 It accepts the following values:
11306 No samples pre-processing (do not expect this to be faster)
11315 Default value is @code{hann}.
11318 The usage is very similar to the showwaves filter; see the examples in that
11321 @subsection Examples
11325 Large window with logarithmic color scaling:
11327 showspectrum=s=1280x480:scale=log
11331 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
11333 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
11334 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
11340 Convert input audio to a video output, representing the samples waves.
11342 The filter accepts the following options:
11346 Specify the video size for the output. For the syntax of this option, check
11347 the "Video size" section in the ffmpeg-utils manual. Default value
11353 Available values are:
11356 Draw a point for each sample.
11359 Draw a vertical line for each sample.
11362 Draw a point for each sample and a line between them.
11365 Draw a centered vertical line for each sample.
11368 Default value is @code{point}.
11371 Set the number of samples which are printed on the same column. A
11372 larger value will decrease the frame rate. Must be a positive
11373 integer. This option can be set only if the value for @var{rate}
11374 is not explicitly specified.
11377 Set the (approximate) output frame rate. This is done by setting the
11378 option @var{n}. Default value is "25".
11380 @item split_channels
11381 Set if channels should be drawn separately or overlap. Default value is 0.
11385 @subsection Examples
11389 Output the input file audio and the corresponding video representation
11392 amovie=a.mp3,asplit[out0],showwaves[out1]
11396 Create a synthetic signal and show it with showwaves, forcing a
11397 frame rate of 30 frames per second:
11399 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
11403 @section split, asplit
11405 Split input into several identical outputs.
11407 @code{asplit} works with audio input, @code{split} with video.
11409 The filter accepts a single parameter which specifies the number of outputs. If
11410 unspecified, it defaults to 2.
11412 @subsection Examples
11416 Create two separate outputs from the same input:
11418 [in] split [out0][out1]
11422 To create 3 or more outputs, you need to specify the number of
11425 [in] asplit=3 [out0][out1][out2]
11429 Create two separate outputs from the same input, one cropped and
11432 [in] split [splitout1][splitout2];
11433 [splitout1] crop=100:100:0:0 [cropout];
11434 [splitout2] pad=200:200:100:100 [padout];
11438 Create 5 copies of the input audio with @command{ffmpeg}:
11440 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
11446 Receive commands sent through a libzmq client, and forward them to
11447 filters in the filtergraph.
11449 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
11450 must be inserted between two video filters, @code{azmq} between two
11453 To enable these filters you need to install the libzmq library and
11454 headers and configure FFmpeg with @code{--enable-libzmq}.
11456 For more information about libzmq see:
11457 @url{http://www.zeromq.org/}
11459 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
11460 receives messages sent through a network interface defined by the
11461 @option{bind_address} option.
11463 The received message must be in the form:
11465 @var{TARGET} @var{COMMAND} [@var{ARG}]
11468 @var{TARGET} specifies the target of the command, usually the name of
11469 the filter class or a specific filter instance name.
11471 @var{COMMAND} specifies the name of the command for the target filter.
11473 @var{ARG} is optional and specifies the optional argument list for the
11474 given @var{COMMAND}.
11476 Upon reception, the message is processed and the corresponding command
11477 is injected into the filtergraph. Depending on the result, the filter
11478 will send a reply to the client, adopting the format:
11480 @var{ERROR_CODE} @var{ERROR_REASON}
11484 @var{MESSAGE} is optional.
11486 @subsection Examples
11488 Look at @file{tools/zmqsend} for an example of a zmq client which can
11489 be used to send commands processed by these filters.
11491 Consider the following filtergraph generated by @command{ffplay}
11493 ffplay -dumpgraph 1 -f lavfi "
11494 color=s=100x100:c=red [l];
11495 color=s=100x100:c=blue [r];
11496 nullsrc=s=200x100, zmq [bg];
11497 [bg][l] overlay [bg+l];
11498 [bg+l][r] overlay=x=100 "
11501 To change the color of the left side of the video, the following
11502 command can be used:
11504 echo Parsed_color_0 c yellow | tools/zmqsend
11507 To change the right side:
11509 echo Parsed_color_1 c pink | tools/zmqsend
11512 @c man end MULTIMEDIA FILTERS
11514 @chapter Multimedia Sources
11515 @c man begin MULTIMEDIA SOURCES
11517 Below is a description of the currently available multimedia sources.
11521 This is the same as @ref{movie} source, except it selects an audio
11527 Read audio and/or video stream(s) from a movie container.
11529 It accepts the following parameters:
11533 The name of the resource to read (not necessarily a file; it can also be a
11534 device or a stream accessed through some protocol).
11536 @item format_name, f
11537 Specifies the format assumed for the movie to read, and can be either
11538 the name of a container or an input device. If not specified, the
11539 format is guessed from @var{movie_name} or by probing.
11541 @item seek_point, sp
11542 Specifies the seek point in seconds. The frames will be output
11543 starting from this seek point. The parameter is evaluated with
11544 @code{av_strtod}, so the numerical value may be suffixed by an IS
11545 postfix. The default value is "0".
11548 Specifies the streams to read. Several streams can be specified,
11549 separated by "+". The source will then have as many outputs, in the
11550 same order. The syntax is explained in the ``Stream specifiers''
11551 section in the ffmpeg manual. Two special names, "dv" and "da" specify
11552 respectively the default (best suited) video and audio stream. Default
11553 is "dv", or "da" if the filter is called as "amovie".
11555 @item stream_index, si
11556 Specifies the index of the video stream to read. If the value is -1,
11557 the most suitable video stream will be automatically selected. The default
11558 value is "-1". Deprecated. If the filter is called "amovie", it will select
11559 audio instead of video.
11562 Specifies how many times to read the stream in sequence.
11563 If the value is less than 1, the stream will be read again and again.
11564 Default value is "1".
11566 Note that when the movie is looped the source timestamps are not
11567 changed, so it will generate non monotonically increasing timestamps.
11570 It allows overlaying a second video on top of the main input of
11571 a filtergraph, as shown in this graph:
11573 input -----------> deltapts0 --> overlay --> output
11576 movie --> scale--> deltapts1 -------+
11578 @subsection Examples
11582 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
11583 on top of the input labelled "in":
11585 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
11586 [in] setpts=PTS-STARTPTS [main];
11587 [main][over] overlay=16:16 [out]
11591 Read from a video4linux2 device, and overlay it on top of the input
11594 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
11595 [in] setpts=PTS-STARTPTS [main];
11596 [main][over] overlay=16:16 [out]
11600 Read the first video stream and the audio stream with id 0x81 from
11601 dvd.vob; the video is connected to the pad named "video" and the audio is
11602 connected to the pad named "audio":
11604 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
11608 @c man end MULTIMEDIA SOURCES