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
12 input --> split ---------------------> overlay --> output
15 +-----> crop --> vflip -------+
18 This filtergraph splits the input stream in two streams, sends one
19 stream through the crop filter and the vflip filter before merging it
20 back with the other stream by overlaying it on top. You can use the
21 following command to achieve this:
24 ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
27 The result will be that in output the top half of the video is mirrored
30 Filters in the same linear chain are separated by commas, and distinct
31 linear chains of filters are separated by semicolons. In our example,
32 @var{crop,vflip} are in one linear chain, @var{split} and
33 @var{overlay} are separately in another. The points where the linear
34 chains join are labelled by names enclosed in square brackets. In the
35 example, the split filter generates two outputs that are associated to
36 the labels @var{[main]} and @var{[tmp]}.
38 The stream sent to the second output of @var{split}, labelled as
39 @var{[tmp]}, is processed through the @var{crop} filter, which crops
40 away the lower half part of the video, and then vertically flipped. The
41 @var{overlay} filter takes in input the first unchanged output of the
42 split filter (which was labelled as @var{[main]}), and overlay on its
43 lower half the output generated by the @var{crop,vflip} filterchain.
45 Some filters take in input a list of parameters: they are specified
46 after the filter name and an equal sign, and are separated from each other
49 There exist so-called @var{source filters} that do not have an
50 audio/video input, and @var{sink filters} that will not have audio/video
53 @c man end FILTERING INTRODUCTION
56 @c man begin GRAPH2DOT
58 The @file{graph2dot} program included in the FFmpeg @file{tools}
59 directory can be used to parse a filtergraph description and issue a
60 corresponding textual representation in the dot language.
67 to see how to use @file{graph2dot}.
69 You can then pass the dot description to the @file{dot} program (from
70 the graphviz suite of programs) and obtain a graphical representation
73 For example the sequence of commands:
75 echo @var{GRAPH_DESCRIPTION} | \
76 tools/graph2dot -o graph.tmp && \
77 dot -Tpng graph.tmp -o graph.png && \
81 can be used to create and display an image representing the graph
82 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
83 a complete self-contained graph, with its inputs and outputs explicitly defined.
84 For example if your command line is of the form:
86 ffmpeg -i infile -vf scale=640:360 outfile
88 your @var{GRAPH_DESCRIPTION} string will need to be of the form:
90 nullsrc,scale=640:360,nullsink
92 you may also need to set the @var{nullsrc} parameters and add a @var{format}
93 filter in order to simulate a specific input file.
97 @chapter Filtergraph description
98 @c man begin FILTERGRAPH DESCRIPTION
100 A filtergraph is a directed graph of connected filters. It can contain
101 cycles, and there can be multiple links between a pair of
102 filters. Each link has one input pad on one side connecting it to one
103 filter from which it takes its input, and one output pad on the other
104 side connecting it to the one filter accepting its output.
106 Each filter in a filtergraph is an instance of a filter class
107 registered in the application, which defines the features and the
108 number of input and output pads of the filter.
110 A filter with no input pads is called a "source", a filter with no
111 output pads is called a "sink".
113 @anchor{Filtergraph syntax}
114 @section Filtergraph syntax
116 A filtergraph can be represented using a textual representation, which is
117 recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
118 options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the
119 @code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} function defined in
120 @file{libavfilter/avfilter.h}.
122 A filterchain consists of a sequence of connected filters, each one
123 connected to the previous one in the sequence. A filterchain is
124 represented by a list of ","-separated filter descriptions.
126 A filtergraph consists of a sequence of filterchains. A sequence of
127 filterchains is represented by a list of ";"-separated filterchain
130 A filter is represented by a string of the form:
131 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
133 @var{filter_name} is the name of the filter class of which the
134 described filter is an instance of, and has to be the name of one of
135 the filter classes registered in the program.
136 The name of the filter class is optionally followed by a string
139 @var{arguments} is a string which contains the parameters used to
140 initialize the filter instance. It may have one of the following forms:
144 A ':'-separated list of @var{key=value} pairs.
147 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
148 the option names in the order they are declared. E.g. the @code{fade} filter
149 declares three options in this order -- @option{type}, @option{start_frame} and
150 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
151 @var{in} is assigned to the option @option{type}, @var{0} to
152 @option{start_frame} and @var{30} to @option{nb_frames}.
155 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
156 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
157 follow the same constraints order of the previous point. The following
158 @var{key=value} pairs can be set in any preferred order.
162 If the option value itself is a list of items (e.g. the @code{format} filter
163 takes a list of pixel formats), the items in the list are usually separated by
166 The list of arguments can be quoted using the character "'" as initial
167 and ending mark, and the character '\' for escaping the characters
168 within the quoted text; otherwise the argument string is considered
169 terminated when the next special character (belonging to the set
170 "[]=;,") is encountered.
172 The name and arguments of the filter are optionally preceded and
173 followed by a list of link labels.
174 A link label allows to name a link and associate it to a filter output
175 or input pad. The preceding labels @var{in_link_1}
176 ... @var{in_link_N}, are associated to the filter input pads,
177 the following labels @var{out_link_1} ... @var{out_link_M}, are
178 associated to the output pads.
180 When two link labels with the same name are found in the
181 filtergraph, a link between the corresponding input and output pad is
184 If an output pad is not labelled, it is linked by default to the first
185 unlabelled input pad of the next filter in the filterchain.
186 For example in the filterchain:
188 nullsrc, split[L1], [L2]overlay, nullsink
190 the split filter instance has two output pads, and the overlay filter
191 instance two input pads. The first output pad of split is labelled
192 "L1", the first input pad of overlay is labelled "L2", and the second
193 output pad of split is linked to the second input pad of overlay,
194 which are both unlabelled.
196 In a complete filterchain all the unlabelled filter input and output
197 pads must be connected. A filtergraph is considered valid if all the
198 filter input and output pads of all the filterchains are connected.
200 Libavfilter will automatically insert scale filters where format
201 conversion is required. It is possible to specify swscale flags
202 for those automatically inserted scalers by prepending
203 @code{sws_flags=@var{flags};}
204 to the filtergraph description.
206 Follows a BNF description for the filtergraph syntax:
208 @var{NAME} ::= sequence of alphanumeric characters and '_'
209 @var{LINKLABEL} ::= "[" @var{NAME} "]"
210 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
211 @var{FILTER_ARGUMENTS} ::= sequence of chars (eventually quoted)
212 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
213 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
214 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
217 @section Notes on filtergraph escaping
219 Some filter arguments require the use of special characters, typically
220 @code{:} to separate key=value pairs in a named options list. In this
221 case the user should perform a first level escaping when specifying
222 the filter arguments. For example, consider the following literal
223 string to be embedded in the @ref{drawtext} filter arguments:
225 this is a 'string': may contain one, or more, special characters
228 Since @code{:} is special for the filter arguments syntax, it needs to
229 be escaped, so you get:
231 text=this is a \'string\'\: may contain one, or more, special characters
234 A second level of escaping is required when embedding the filter
235 arguments in a filtergraph description, in order to escape all the
236 filtergraph special characters. Thus the example above becomes:
238 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
241 Finally an additional level of escaping may be needed when writing the
242 filtergraph description in a shell command, which depends on the
243 escaping rules of the adopted shell. For example, assuming that
244 @code{\} is special and needs to be escaped with another @code{\}, the
245 previous string will finally result in:
247 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
250 Sometimes, it might be more convenient to employ quoting in place of
251 escaping. For example the string:
253 Caesar: tu quoque, Brute, fili mi
256 Can be quoted in the filter arguments as:
258 text='Caesar: tu quoque, Brute, fili mi'
261 And finally inserted in a filtergraph like:
263 drawtext=text=\'Caesar: tu quoque\, Brute\, fili mi\'
266 See the ``Quoting and escaping'' section in the ffmpeg-utils manual
267 for more information about the escaping and quoting rules adopted by
270 @chapter Timeline editing
272 Some filters support a generic @option{enable} option. For the filters
273 supporting timeline editing, this option can be set to an expression which is
274 evaluated before sending a frame to the filter. If the evaluation is non-zero,
275 the filter will be enabled, otherwise the frame will be sent unchanged to the
276 next filter in the filtergraph.
278 The expression accepts the following values:
281 timestamp expressed in seconds, NAN if the input timestamp is unknown
284 sequential number of the input frame, starting from 0
287 the position in the file of the input frame, NAN if unknown
290 Additionally, these filters support an @option{enable} command that can be used
291 to re-define the expression.
293 Like any other filtering option, the @option{enable} option follows the same
296 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
297 minutes, and a @ref{curves} filter starting at 3 seconds:
299 smartblur = enable='between(t,10,3*60)',
300 curves = enable='gte(t,3)' : preset=cross_process
303 @c man end FILTERGRAPH DESCRIPTION
305 @chapter Audio Filters
306 @c man begin AUDIO FILTERS
308 When you configure your FFmpeg build, you can disable any of the
309 existing filters using @code{--disable-filters}.
310 The configure output will show the audio filters included in your
313 Below is a description of the currently available audio filters.
317 Convert the input audio format to the specified formats.
319 @emph{This filter is deprecated. Use @ref{aformat} instead.}
321 The filter accepts a string of the form:
322 "@var{sample_format}:@var{channel_layout}".
324 @var{sample_format} specifies the sample format, and can be a string or the
325 corresponding numeric value defined in @file{libavutil/samplefmt.h}. Use 'p'
326 suffix for a planar sample format.
328 @var{channel_layout} specifies the channel layout, and can be a string
329 or the corresponding number value defined in @file{libavutil/channel_layout.h}.
331 The special parameter "auto", signifies that the filter will
332 automatically select the output format depending on the output filter.
338 Convert input to float, planar, stereo:
344 Convert input to unsigned 8-bit, automatically select out channel layout:
352 Apply fade-in/out effect to input audio.
354 A description of the accepted parameters follows.
358 Specify the effect type, can be either @code{in} for fade-in, or
359 @code{out} for a fade-out effect. Default is @code{in}.
361 @item start_sample, ss
362 Specify the number of the start sample for starting to apply the fade
363 effect. Default is 0.
366 Specify the number of samples for which the fade effect has to last. At
367 the end of the fade-in effect the output audio will have the same
368 volume as the input audio, at the end of the fade-out transition
369 the output audio will be silence. Default is 44100.
372 Specify time for starting to apply the fade effect. Default is 0.
373 The accepted syntax is:
375 [-]HH[:MM[:SS[.m...]]]
378 See also the function @code{av_parse_time()}.
379 If set this option is used instead of @var{start_sample} one.
382 Specify the duration for which the fade effect has to last. Default is 0.
383 The accepted syntax is:
385 [-]HH[:MM[:SS[.m...]]]
388 See also the function @code{av_parse_time()}.
389 At the end of the fade-in effect the output audio will have the same
390 volume as the input audio, at the end of the fade-out transition
391 the output audio will be silence.
392 If set this option is used instead of @var{nb_samples} one.
395 Set curve for fade transition.
397 It accepts the following values:
400 select triangular, linear slope (default)
402 select quarter of sine wave
404 select half of sine wave
406 select exponential sine wave
410 select inverted parabola
426 Fade in first 15 seconds of audio:
432 Fade out last 25 seconds of a 900 seconds audio:
434 afade=t=out:st=875:d=25
441 Set output format constraints for the input audio. The framework will
442 negotiate the most appropriate format to minimize conversions.
444 The filter accepts the following named parameters:
448 A '|'-separated list of requested sample formats.
451 A '|'-separated list of requested sample rates.
453 @item channel_layouts
454 A '|'-separated list of requested channel layouts.
458 If a parameter is omitted, all values are allowed.
460 For example to force the output to either unsigned 8-bit or signed 16-bit stereo:
462 aformat=sample_fmts=u8|s16:channel_layouts=stereo
467 Apply a two-pole all-pass filter with central frequency (in Hz)
468 @var{frequency}, and filter-width @var{width}.
469 An all-pass filter changes the audio's frequency to phase relationship
470 without changing its frequency to amplitude relationship.
472 The filter accepts the following options:
479 Set method to specify band-width of filter.
492 Specify the band-width of a filter in width_type units.
497 Merge two or more audio streams into a single multi-channel stream.
499 The filter accepts the following options:
504 Set the number of inputs. Default is 2.
508 If the channel layouts of the inputs are disjoint, and therefore compatible,
509 the channel layout of the output will be set accordingly and the channels
510 will be reordered as necessary. If the channel layouts of the inputs are not
511 disjoint, the output will have all the channels of the first input then all
512 the channels of the second input, in that order, and the channel layout of
513 the output will be the default value corresponding to the total number of
516 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
517 is FC+BL+BR, then the output will be in 5.1, with the channels in the
518 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
519 first input, b1 is the first channel of the second input).
521 On the other hand, if both input are in stereo, the output channels will be
522 in the default order: a1, a2, b1, b2, and the channel layout will be
523 arbitrarily set to 4.0, which may or may not be the expected value.
525 All inputs must have the same sample rate, and format.
527 If inputs do not have the same duration, the output will stop with the
534 Merge two mono files into a stereo stream:
536 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
540 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
542 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
548 Mixes multiple audio inputs into a single output.
552 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
554 will mix 3 input audio streams to a single output with the same duration as the
555 first input and a dropout transition time of 3 seconds.
557 The filter accepts the following named parameters:
561 Number of inputs. If unspecified, it defaults to 2.
564 How to determine the end-of-stream.
568 Duration of longest input. (default)
571 Duration of shortest input.
574 Duration of first input.
578 @item dropout_transition
579 Transition time, in seconds, for volume renormalization when an input
580 stream ends. The default value is 2 seconds.
586 Pass the audio source unchanged to the output.
590 Pad the end of a audio stream with silence, this can be used together with
591 -shortest to extend audio streams to the same length as the video stream.
594 Add a phasing effect to the input audio.
596 A phaser filter creates series of peaks and troughs in the frequency spectrum.
597 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
599 A description of the accepted parameters follows.
603 Set input gain. Default is 0.4.
606 Set output gain. Default is 0.74
609 Set delay in milliseconds. Default is 3.0.
612 Set decay. Default is 0.4.
615 Set modulation speed in Hz. Default is 0.5.
618 Set modulation type. Default is triangular.
620 It accepts the following values:
630 Resample the input audio to the specified parameters, using the
631 libswresample library. If none are specified then the filter will
632 automatically convert between its input and output.
634 This filter is also able to stretch/squeeze the audio data to make it match
635 the timestamps or to inject silence / cut out audio to make it match the
636 timestamps, do a combination of both or do neither.
638 The filter accepts the syntax
639 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
640 expresses a sample rate and @var{resampler_options} is a list of
641 @var{key}=@var{value} pairs, separated by ":". See the
642 ffmpeg-resampler manual for the complete list of supported options.
648 Resample the input audio to 44100Hz:
654 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
655 samples per second compensation:
661 @section asetnsamples
663 Set the number of samples per each output audio frame.
665 The last output packet may contain a different number of samples, as
666 the filter will flush all the remaining samples when the input audio
669 The filter accepts the following options:
673 @item nb_out_samples, n
674 Set the number of frames per each output audio frame. The number is
675 intended as the number of samples @emph{per each channel}.
676 Default value is 1024.
679 If set to 1, the filter will pad the last audio frame with zeroes, so
680 that the last frame will contain the same number of samples as the
681 previous ones. Default value is 1.
684 For example, to set the number of per-frame samples to 1234 and
685 disable padding for the last frame, use:
687 asetnsamples=n=1234:p=0
692 Set the sample rate without altering the PCM data.
693 This will result in a change of speed and pitch.
695 The filter accepts the following options:
699 Set the output sample rate. Default is 44100 Hz.
704 Show a line containing various information for each input audio frame.
705 The input audio is not modified.
707 The shown line contains a sequence of key/value pairs of the form
708 @var{key}:@var{value}.
710 A description of each shown parameter follows:
714 sequential number of the input frame, starting from 0
717 Presentation timestamp of the input frame, in time base units; the time base
718 depends on the filter input pad, and is usually 1/@var{sample_rate}.
721 presentation timestamp of the input frame in seconds
724 position of the frame in the input stream, -1 if this information in
725 unavailable and/or meaningless (for example in case of synthetic audio)
734 sample rate for the audio frame
737 number of samples (per channel) in the frame
740 Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio
741 the data is treated as if all the planes were concatenated.
743 @item plane_checksums
744 A list of Adler-32 checksums for each data plane.
749 Display time domain statistical information about the audio channels.
750 Statistics are calculated and displayed for each audio channel and,
751 where applicable, an overall figure is also given.
753 The filter accepts the following option:
756 Short window length in seconds, used for peak and trough RMS measurement.
757 Default is @code{0.05} (50 miliseconds). Allowed range is @code{[0.1 - 10]}.
760 A description of each shown parameter follows:
764 Mean amplitude displacement from zero.
767 Minimal sample level.
770 Maximal sample level.
774 Standard peak and RMS level measured in dBFS.
778 Peak and trough values for RMS level measured over a short window.
781 Standard ratio of peak to RMS level (note: not in dB).
784 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
785 (i.e. either @var{Min level} or @var{Max level}).
788 Number of occasions (not the number of samples) that the signal attained either
789 @var{Min level} or @var{Max level}.
794 Forward two audio streams and control the order the buffers are forwarded.
796 The filter accepts the following options:
800 Set the expression deciding which stream should be
801 forwarded next: if the result is negative, the first stream is forwarded; if
802 the result is positive or zero, the second stream is forwarded. It can use
803 the following variables:
807 number of buffers forwarded so far on each stream
809 number of samples forwarded so far on each stream
811 current timestamp of each stream
814 The default value is @code{t1-t2}, which means to always forward the stream
815 that has a smaller timestamp.
820 Stress-test @code{amerge} by randomly sending buffers on the wrong
821 input, while avoiding too much of a desynchronization:
823 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
824 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
830 Synchronize audio data with timestamps by squeezing/stretching it and/or
831 dropping samples/adding silence when needed.
833 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
835 The filter accepts the following named parameters:
839 Enable stretching/squeezing the data to make it match the timestamps. Disabled
840 by default. When disabled, time gaps are covered with silence.
843 Minimum difference between timestamps and audio data (in seconds) to trigger
844 adding/dropping samples. Default value is 0.1. If you get non-perfect sync with
845 this filter, try setting this parameter to 0.
848 Maximum compensation in samples per second. Relevant only with compensate=1.
852 Assume the first pts should be this value. The time base is 1 / sample rate.
853 This allows for padding/trimming at the start of stream. By default, no
854 assumption is made about the first frame's expected pts, so no padding or
855 trimming is done. For example, this could be set to 0 to pad the beginning with
856 silence if an audio stream starts after the video stream or to trim any samples
857 with a negative pts due to encoder delay.
865 The filter accepts exactly one parameter, the audio tempo. If not
866 specified then the filter will assume nominal 1.0 tempo. Tempo must
867 be in the [0.5, 2.0] range.
873 Slow down audio to 80% tempo:
879 To speed up audio to 125% tempo:
887 Trim the input so that the output contains one continuous subpart of the input.
889 This filter accepts the following options:
892 Timestamp (in seconds) of the start of the kept section. I.e. the audio sample
893 with the timestamp @var{start} will be the first sample in the output.
896 Timestamp (in seconds) of the first audio sample that will be dropped. I.e. the
897 audio sample immediately preceding the one with the timestamp @var{end} will be
898 the last sample in the output.
901 Same as @var{start}, except this option sets the start timestamp in samples
905 Same as @var{end}, except this option sets the end timestamp in samples instead
909 Maximum duration of the output in seconds.
912 Number of the first sample that should be passed to output.
915 Number of the first sample that should be dropped.
918 Note that the first two sets of the start/end options and the @option{duration}
919 option look at the frame timestamp, while the _sample options simply count the
920 samples that pass through the filter. So start/end_pts and start/end_sample will
921 give different results when the timestamps are wrong, inexact or do not start at
922 zero. Also note that this filter does not modify the timestamps. If you wish
923 that the output timestamps start at zero, insert the asetpts filter after the
926 If multiple start or end options are set, this filter tries to be greedy and
927 keep all samples that match at least one of the specified constraints. To keep
928 only the part that matches all the constraints at once, chain multiple atrim
931 The defaults are such that all the input is kept. So it is possible to set e.g.
932 just the end values to keep everything before the specified time.
937 drop everything except the second minute of input
939 ffmpeg -i INPUT -af atrim=60:120
943 keep only the first 1000 samples
945 ffmpeg -i INPUT -af atrim=end_sample=1000
952 Apply a two-pole Butterworth band-pass filter with central
953 frequency @var{frequency}, and (3dB-point) band-width width.
954 The @var{csg} option selects a constant skirt gain (peak gain = Q)
955 instead of the default: constant 0dB peak gain.
956 The filter roll off at 6dB per octave (20dB per decade).
958 The filter accepts the following options:
962 Set the filter's central frequency. Default is @code{3000}.
965 Constant skirt gain if set to 1. Defaults to 0.
968 Set method to specify band-width of filter.
981 Specify the band-width of a filter in width_type units.
986 Apply a two-pole Butterworth band-reject filter with central
987 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
988 The filter roll off at 6dB per octave (20dB per decade).
990 The filter accepts the following options:
994 Set the filter's central frequency. Default is @code{3000}.
997 Set method to specify band-width of filter.
1010 Specify the band-width of a filter in width_type units.
1015 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1016 shelving filter with a response similar to that of a standard
1017 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1019 The filter accepts the following options:
1023 Give the gain at 0 Hz. Its useful range is about -20
1024 (for a large cut) to +20 (for a large boost).
1025 Beware of clipping when using a positive gain.
1028 Set the filter's central frequency and so can be used
1029 to extend or reduce the frequency range to be boosted or cut.
1030 The default value is @code{100} Hz.
1033 Set method to specify band-width of filter.
1046 Determine how steep is the filter's shelf transition.
1051 Apply a biquad IIR filter with the given coefficients.
1052 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1053 are the numerator and denominator coefficients respectively.
1057 Remap input channels to new locations.
1059 This filter accepts the following named parameters:
1061 @item channel_layout
1062 Channel layout of the output stream.
1065 Map channels from input to output. The argument is a '|'-separated list of
1066 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1067 @var{in_channel} form. @var{in_channel} can be either the name of the input
1068 channel (e.g. FL for front left) or its index in the input channel layout.
1069 @var{out_channel} is the name of the output channel or its index in the output
1070 channel layout. If @var{out_channel} is not given then it is implicitly an
1071 index, starting with zero and increasing by one for each mapping.
1074 If no mapping is present, the filter will implicitly map input channels to
1075 output channels preserving index.
1077 For example, assuming a 5.1+downmix input MOV file
1079 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1081 will create an output WAV file tagged as stereo from the downmix channels of
1084 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1086 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1089 @section channelsplit
1091 Split each channel in input audio stream into a separate output stream.
1093 This filter accepts the following named parameters:
1095 @item channel_layout
1096 Channel layout of the input stream. Default is "stereo".
1099 For example, assuming a stereo input MP3 file
1101 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1103 will create an output Matroska file with two audio streams, one containing only
1104 the left channel and the other the right channel.
1106 To split a 5.1 WAV file into per-channel files
1108 ffmpeg -i in.wav -filter_complex
1109 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1110 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1111 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1117 Make audio easier to listen to on headphones.
1119 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1120 so that when listened to on headphones the stereo image is moved from
1121 inside your head (standard for headphones) to outside and in front of
1122 the listener (standard for speakers).
1128 Apply a two-pole peaking equalisation (EQ) filter. With this
1129 filter, the signal-level at and around a selected frequency can
1130 be increased or decreased, whilst (unlike bandpass and bandreject
1131 filters) that at all other frequencies is unchanged.
1133 In order to produce complex equalisation curves, this filter can
1134 be given several times, each with a different central frequency.
1136 The filter accepts the following options:
1140 Set the filter's central frequency in Hz.
1143 Set method to specify band-width of filter.
1156 Specify the band-width of a filter in width_type units.
1159 Set the required gain or attenuation in dB.
1160 Beware of clipping when using a positive gain.
1165 Apply a high-pass filter with 3dB point frequency.
1166 The filter can be either single-pole, or double-pole (the default).
1167 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1169 The filter accepts the following options:
1173 Set frequency in Hz. Default is 3000.
1176 Set number of poles. Default is 2.
1179 Set method to specify band-width of filter.
1192 Specify the band-width of a filter in width_type units.
1193 Applies only to double-pole filter.
1194 The default is 0.707q and gives a Butterworth response.
1199 Join multiple input streams into one multi-channel stream.
1201 The filter accepts the following named parameters:
1205 Number of input streams. Defaults to 2.
1207 @item channel_layout
1208 Desired output channel layout. Defaults to stereo.
1211 Map channels from inputs to output. The argument is a '|'-separated list of
1212 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1213 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1214 can be either the name of the input channel (e.g. FL for front left) or its
1215 index in the specified input stream. @var{out_channel} is the name of the output
1219 The filter will attempt to guess the mappings when those are not specified
1220 explicitly. It does so by first trying to find an unused matching input channel
1221 and if that fails it picks the first unused input channel.
1223 E.g. to join 3 inputs (with properly set channel layouts)
1225 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1228 To build a 5.1 output from 6 single-channel streams:
1230 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1231 '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'
1237 Apply a low-pass filter with 3dB point frequency.
1238 The filter can be either single-pole or double-pole (the default).
1239 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1241 The filter accepts the following options:
1245 Set frequency in Hz. Default is 500.
1248 Set number of poles. Default is 2.
1251 Set method to specify band-width of filter.
1264 Specify the band-width of a filter in width_type units.
1265 Applies only to double-pole filter.
1266 The default is 0.707q and gives a Butterworth response.
1271 Mix channels with specific gain levels. The filter accepts the output
1272 channel layout followed by a set of channels definitions.
1274 This filter is also designed to remap efficiently the channels of an audio
1277 The filter accepts parameters of the form:
1278 "@var{l}:@var{outdef}:@var{outdef}:..."
1282 output channel layout or number of channels
1285 output channel specification, of the form:
1286 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1289 output channel to define, either a channel name (FL, FR, etc.) or a channel
1290 number (c0, c1, etc.)
1293 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1296 input channel to use, see out_name for details; it is not possible to mix
1297 named and numbered input channels
1300 If the `=' in a channel specification is replaced by `<', then the gains for
1301 that specification will be renormalized so that the total is 1, thus
1302 avoiding clipping noise.
1304 @subsection Mixing examples
1306 For example, if you want to down-mix from stereo to mono, but with a bigger
1307 factor for the left channel:
1309 pan=1:c0=0.9*c0+0.1*c1
1312 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1313 7-channels surround:
1315 pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1318 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1319 that should be preferred (see "-ac" option) unless you have very specific
1322 @subsection Remapping examples
1324 The channel remapping will be effective if, and only if:
1327 @item gain coefficients are zeroes or ones,
1328 @item only one input per channel output,
1331 If all these conditions are satisfied, the filter will notify the user ("Pure
1332 channel mapping detected"), and use an optimized and lossless method to do the
1335 For example, if you have a 5.1 source and want a stereo audio stream by
1336 dropping the extra channels:
1338 pan="stereo: c0=FL : c1=FR"
1341 Given the same source, you can also switch front left and front right channels
1342 and keep the input channel layout:
1344 pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
1347 If the input is a stereo audio stream, you can mute the front left channel (and
1348 still keep the stereo channel layout) with:
1353 Still with a stereo audio stream input, you can copy the right channel in both
1354 front left and right:
1356 pan="stereo: c0=FR : c1=FR"
1361 Convert the audio sample format, sample rate and channel layout. This filter is
1362 not meant to be used directly.
1364 @section silencedetect
1366 Detect silence in an audio stream.
1368 This filter logs a message when it detects that the input audio volume is less
1369 or equal to a noise tolerance value for a duration greater or equal to the
1370 minimum detected noise duration.
1372 The printed times and duration are expressed in seconds.
1374 The filter accepts the following options:
1378 Set silence duration until notification (default is 2 seconds).
1381 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1382 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1385 @subsection Examples
1389 Detect 5 seconds of silence with -50dB noise tolerance:
1391 silencedetect=n=-50dB:d=5
1395 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1396 tolerance in @file{silence.mp3}:
1398 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1404 Boost or cut treble (upper) frequencies of the audio using a two-pole
1405 shelving filter with a response similar to that of a standard
1406 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1408 The filter accepts the following options:
1412 Give the gain at whichever is the lower of ~22 kHz and the
1413 Nyquist frequency. Its useful range is about -20 (for a large cut)
1414 to +20 (for a large boost). Beware of clipping when using a positive gain.
1417 Set the filter's central frequency and so can be used
1418 to extend or reduce the frequency range to be boosted or cut.
1419 The default value is @code{3000} Hz.
1422 Set method to specify band-width of filter.
1435 Determine how steep is the filter's shelf transition.
1440 Adjust the input audio volume.
1442 The filter accepts the following options:
1447 Expresses how the audio volume will be increased or decreased.
1449 Output values are clipped to the maximum value.
1451 The output audio volume is given by the relation:
1453 @var{output_volume} = @var{volume} * @var{input_volume}
1456 Default value for @var{volume} is 1.0.
1459 Set the mathematical precision.
1461 This determines which input sample formats will be allowed, which affects the
1462 precision of the volume scaling.
1466 8-bit fixed-point; limits input sample format to U8, S16, and S32.
1468 32-bit floating-point; limits input sample format to FLT. (default)
1470 64-bit floating-point; limits input sample format to DBL.
1474 @subsection Examples
1478 Halve the input audio volume:
1482 volume=volume=-6.0206dB
1485 In all the above example the named key for @option{volume} can be
1486 omitted, for example like in:
1492 Increase input audio power by 6 decibels using fixed-point precision:
1494 volume=volume=6dB:precision=fixed
1498 @section volumedetect
1500 Detect the volume of the input video.
1502 The filter has no parameters. The input is not modified. Statistics about
1503 the volume will be printed in the log when the input stream end is reached.
1505 In particular it will show the mean volume (root mean square), maximum
1506 volume (on a per-sample basis), and the beginning of an histogram of the
1507 registered volume values (from the maximum value to a cumulated 1/1000 of
1510 All volumes are in decibels relative to the maximum PCM value.
1512 @subsection Examples
1514 Here is an excerpt of the output:
1516 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
1517 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
1518 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
1519 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
1520 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
1521 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
1522 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
1523 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
1524 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
1530 The mean square energy is approximately -27 dB, or 10^-2.7.
1532 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
1534 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
1537 In other words, raising the volume by +4 dB does not cause any clipping,
1538 raising it by +5 dB causes clipping for 6 samples, etc.
1540 @c man end AUDIO FILTERS
1542 @chapter Audio Sources
1543 @c man begin AUDIO SOURCES
1545 Below is a description of the currently available audio sources.
1549 Buffer audio frames, and make them available to the filter chain.
1551 This source is mainly intended for a programmatic use, in particular
1552 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
1554 It accepts the following named parameters:
1559 Timebase which will be used for timestamps of submitted frames. It must be
1560 either a floating-point number or in @var{numerator}/@var{denominator} form.
1563 The sample rate of the incoming audio buffers.
1566 The sample format of the incoming audio buffers.
1567 Either a sample format name or its corresponging integer representation from
1568 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
1570 @item channel_layout
1571 The channel layout of the incoming audio buffers.
1572 Either a channel layout name from channel_layout_map in
1573 @file{libavutil/channel_layout.c} or its corresponding integer representation
1574 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
1577 The number of channels of the incoming audio buffers.
1578 If both @var{channels} and @var{channel_layout} are specified, then they
1583 @subsection Examples
1586 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
1589 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
1590 Since the sample format with name "s16p" corresponds to the number
1591 6 and the "stereo" channel layout corresponds to the value 0x3, this is
1594 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
1599 Generate an audio signal specified by an expression.
1601 This source accepts in input one or more expressions (one for each
1602 channel), which are evaluated and used to generate a corresponding
1605 This source accepts the following options:
1609 Set the '|'-separated expressions list for each separate channel. In case the
1610 @option{channel_layout} option is not specified, the selected channel layout
1611 depends on the number of provided expressions.
1613 @item channel_layout, c
1614 Set the channel layout. The number of channels in the specified layout
1615 must be equal to the number of specified expressions.
1618 Set the minimum duration of the sourced audio. See the function
1619 @code{av_parse_time()} for the accepted format.
1620 Note that the resulting duration may be greater than the specified
1621 duration, as the generated audio is always cut at the end of a
1624 If not specified, or the expressed duration is negative, the audio is
1625 supposed to be generated forever.
1628 Set the number of samples per channel per each output frame,
1631 @item sample_rate, s
1632 Specify the sample rate, default to 44100.
1635 Each expression in @var{exprs} can contain the following constants:
1639 number of the evaluated sample, starting from 0
1642 time of the evaluated sample expressed in seconds, starting from 0
1649 @subsection Examples
1659 Generate a sin signal with frequency of 440 Hz, set sample rate to
1662 aevalsrc="sin(440*2*PI*t):s=8000"
1666 Generate a two channels signal, specify the channel layout (Front
1667 Center + Back Center) explicitly:
1669 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
1673 Generate white noise:
1675 aevalsrc="-2+random(0)"
1679 Generate an amplitude modulated signal:
1681 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
1685 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
1687 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
1694 Null audio source, return unprocessed audio frames. It is mainly useful
1695 as a template and to be employed in analysis / debugging tools, or as
1696 the source for filters which ignore the input data (for example the sox
1699 This source accepts the following options:
1703 @item channel_layout, cl
1705 Specify the channel layout, and can be either an integer or a string
1706 representing a channel layout. The default value of @var{channel_layout}
1709 Check the channel_layout_map definition in
1710 @file{libavutil/channel_layout.c} for the mapping between strings and
1711 channel layout values.
1713 @item sample_rate, r
1714 Specify the sample rate, and defaults to 44100.
1717 Set the number of samples per requested frames.
1721 @subsection Examples
1725 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
1727 anullsrc=r=48000:cl=4
1731 Do the same operation with a more obvious syntax:
1733 anullsrc=r=48000:cl=mono
1737 All the parameters need to be explicitly defined.
1741 Synthesize a voice utterance using the libflite library.
1743 To enable compilation of this filter you need to configure FFmpeg with
1744 @code{--enable-libflite}.
1746 Note that the flite library is not thread-safe.
1748 The filter accepts the following options:
1753 If set to 1, list the names of the available voices and exit
1754 immediately. Default value is 0.
1757 Set the maximum number of samples per frame. Default value is 512.
1760 Set the filename containing the text to speak.
1763 Set the text to speak.
1766 Set the voice to use for the speech synthesis. Default value is
1767 @code{kal}. See also the @var{list_voices} option.
1770 @subsection Examples
1774 Read from file @file{speech.txt}, and synthetize the text using the
1775 standard flite voice:
1777 flite=textfile=speech.txt
1781 Read the specified text selecting the @code{slt} voice:
1783 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
1787 Input text to ffmpeg:
1789 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
1793 Make @file{ffplay} speak the specified text, using @code{flite} and
1794 the @code{lavfi} device:
1796 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
1800 For more information about libflite, check:
1801 @url{http://www.speech.cs.cmu.edu/flite/}
1805 Generate an audio signal made of a sine wave with amplitude 1/8.
1807 The audio signal is bit-exact.
1809 The filter accepts the following options:
1814 Set the carrier frequency. Default is 440 Hz.
1816 @item beep_factor, b
1817 Enable a periodic beep every second with frequency @var{beep_factor} times
1818 the carrier frequency. Default is 0, meaning the beep is disabled.
1820 @item sample_rate, s
1821 Specify the sample rate, default is 44100.
1824 Specify the duration of the generated audio stream.
1826 @item samples_per_frame
1827 Set the number of samples per output frame, default is 1024.
1830 @subsection Examples
1835 Generate a simple 440 Hz sine wave:
1841 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
1845 sine=frequency=220:beep_factor=4:duration=5
1850 @c man end AUDIO SOURCES
1852 @chapter Audio Sinks
1853 @c man begin AUDIO SINKS
1855 Below is a description of the currently available audio sinks.
1857 @section abuffersink
1859 Buffer audio frames, and make them available to the end of filter chain.
1861 This sink is mainly intended for programmatic use, in particular
1862 through the interface defined in @file{libavfilter/buffersink.h}
1863 or the options system.
1865 It accepts a pointer to an AVABufferSinkContext structure, which
1866 defines the incoming buffers' formats, to be passed as the opaque
1867 parameter to @code{avfilter_init_filter} for initialization.
1871 Null audio sink, do absolutely nothing with the input audio. It is
1872 mainly useful as a template and to be employed in analysis / debugging
1875 @c man end AUDIO SINKS
1877 @chapter Video Filters
1878 @c man begin VIDEO FILTERS
1880 When you configure your FFmpeg build, you can disable any of the
1881 existing filters using @code{--disable-filters}.
1882 The configure output will show the video filters included in your
1885 Below is a description of the currently available video filters.
1887 @section alphaextract
1889 Extract the alpha component from the input as a grayscale video. This
1890 is especially useful with the @var{alphamerge} filter.
1894 Add or replace the alpha component of the primary input with the
1895 grayscale value of a second input. This is intended for use with
1896 @var{alphaextract} to allow the transmission or storage of frame
1897 sequences that have alpha in a format that doesn't support an alpha
1900 For example, to reconstruct full frames from a normal YUV-encoded video
1901 and a separate video created with @var{alphaextract}, you might use:
1903 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
1906 Since this filter is designed for reconstruction, it operates on frame
1907 sequences without considering timestamps, and terminates when either
1908 input reaches end of stream. This will cause problems if your encoding
1909 pipeline drops frames. If you're trying to apply an image as an
1910 overlay to a video stream, consider the @var{overlay} filter instead.
1914 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
1915 and libavformat to work. On the other hand, it is limited to ASS (Advanced
1916 Substation Alpha) subtitles files.
1920 Compute the bounding box for the non-black pixels in the input frame
1923 This filter computes the bounding box containing all the pixels with a
1924 luminance value greater than the minimum allowed value.
1925 The parameters describing the bounding box are printed on the filter
1928 @section blackdetect
1930 Detect video intervals that are (almost) completely black. Can be
1931 useful to detect chapter transitions, commercials, or invalid
1932 recordings. Output lines contains the time for the start, end and
1933 duration of the detected black interval expressed in seconds.
1935 In order to display the output lines, you need to set the loglevel at
1936 least to the AV_LOG_INFO value.
1938 The filter accepts the following options:
1941 @item black_min_duration, d
1942 Set the minimum detected black duration expressed in seconds. It must
1943 be a non-negative floating point number.
1945 Default value is 2.0.
1947 @item picture_black_ratio_th, pic_th
1948 Set the threshold for considering a picture "black".
1949 Express the minimum value for the ratio:
1951 @var{nb_black_pixels} / @var{nb_pixels}
1954 for which a picture is considered black.
1955 Default value is 0.98.
1957 @item pixel_black_th, pix_th
1958 Set the threshold for considering a pixel "black".
1960 The threshold expresses the maximum pixel luminance value for which a
1961 pixel is considered "black". The provided value is scaled according to
1962 the following equation:
1964 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
1967 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
1968 the input video format, the range is [0-255] for YUV full-range
1969 formats and [16-235] for YUV non full-range formats.
1971 Default value is 0.10.
1974 The following example sets the maximum pixel threshold to the minimum
1975 value, and detects only black intervals of 2 or more seconds:
1977 blackdetect=d=2:pix_th=0.00
1982 Detect frames that are (almost) completely black. Can be useful to
1983 detect chapter transitions or commercials. Output lines consist of
1984 the frame number of the detected frame, the percentage of blackness,
1985 the position in the file if known or -1 and the timestamp in seconds.
1987 In order to display the output lines, you need to set the loglevel at
1988 least to the AV_LOG_INFO value.
1990 The filter accepts the following options:
1995 Set the percentage of the pixels that have to be below the threshold, defaults
1998 @item threshold, thresh
1999 Set the threshold below which a pixel value is considered black, defaults to
2006 Blend two video frames into each other.
2008 It takes two input streams and outputs one stream, the first input is the
2009 "top" layer and second input is "bottom" layer.
2010 Output terminates when shortest input terminates.
2012 A description of the accepted options follows.
2020 Set blend mode for specific pixel component or all pixel components in case
2021 of @var{all_mode}. Default value is @code{normal}.
2023 Available values for component modes are:
2056 Set blend opacity for specific pixel component or all pixel components in case
2057 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2064 Set blend expression for specific pixel component or all pixel components in case
2065 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2067 The expressions can use the following variables:
2071 The sequential number of the filtered frame, starting from @code{0}.
2075 the coordinates of the current sample
2079 the width and height of currently filtered plane
2083 Width and height scale depending on the currently filtered plane. It is the
2084 ratio between the corresponding luma plane number of pixels and the current
2085 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2086 @code{0.5,0.5} for chroma planes.
2089 Time of the current frame, expressed in seconds.
2092 Value of pixel component at current location for first video frame (top layer).
2095 Value of pixel component at current location for second video frame (bottom layer).
2099 @subsection Examples
2103 Apply transition from bottom layer to top layer in first 10 seconds:
2105 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2109 Apply 1x1 checkerboard effect:
2111 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2117 Apply boxblur algorithm to the input video.
2119 The filter accepts the following options:
2123 @item luma_radius, lr
2124 @item luma_power, lp
2125 @item chroma_radius, cr
2126 @item chroma_power, cp
2127 @item alpha_radius, ar
2128 @item alpha_power, ap
2132 A description of the accepted options follows.
2135 @item luma_radius, lr
2136 @item chroma_radius, cr
2137 @item alpha_radius, ar
2138 Set an expression for the box radius in pixels used for blurring the
2139 corresponding input plane.
2141 The radius value must be a non-negative number, and must not be
2142 greater than the value of the expression @code{min(w,h)/2} for the
2143 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2146 Default value for @option{luma_radius} is "2". If not specified,
2147 @option{chroma_radius} and @option{alpha_radius} default to the
2148 corresponding value set for @option{luma_radius}.
2150 The expressions can contain the following constants:
2154 the input width and height in pixels
2158 the input chroma image width and height in pixels
2162 horizontal and vertical chroma subsample values. For example for the
2163 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2166 @item luma_power, lp
2167 @item chroma_power, cp
2168 @item alpha_power, ap
2169 Specify how many times the boxblur filter is applied to the
2170 corresponding plane.
2172 Default value for @option{luma_power} is 2. If not specified,
2173 @option{chroma_power} and @option{alpha_power} default to the
2174 corresponding value set for @option{luma_power}.
2176 A value of 0 will disable the effect.
2179 @subsection Examples
2183 Apply a boxblur filter with luma, chroma, and alpha radius
2186 boxblur=luma_radius=2:luma_power=1
2191 Set luma radius to 2, alpha and chroma radius to 0:
2193 boxblur=2:1:cr=0:ar=0
2197 Set luma and chroma radius to a fraction of the video dimension:
2199 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2203 @section colorbalance
2204 Modify intensity of primary colors (red, green and blue) of input frames.
2206 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2207 regions for the red-cyan, green-magenta or blue-yellow balance.
2209 A positive adjustment value shifts the balance towards the primary color, a negative
2210 value towards the complementary color.
2212 The filter accepts the following options:
2218 Adjust red, green and blue shadows (darkest pixels).
2223 Adjust red, green and blue midtones (medium pixels).
2228 Adjust red, green and blue highlights (brightest pixels).
2230 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2233 @subsection Examples
2237 Add red color cast to shadows:
2243 @section colorchannelmixer
2245 Adjust video input frames by re-mixing color channels.
2247 This filter modifies a color channel by adding the values associated to
2248 the other channels of the same pixels. For example if the value to
2249 modify is red, the output value will be:
2251 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2254 The filter accepts the following options:
2261 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2262 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2268 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2269 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2275 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2276 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2282 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2283 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2285 Allowed ranges for options are @code{[-2.0, 2.0]}.
2288 @subsection Examples
2292 Convert source to grayscale:
2294 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2298 @section colormatrix
2300 Convert color matrix.
2302 The filter accepts the following options:
2307 Specify the source and destination color matrix. Both values must be
2310 The accepted values are:
2326 For example to convert from BT.601 to SMPTE-240M, use the command:
2328 colormatrix=bt601:smpte240m
2333 Copy the input source unchanged to the output. Mainly useful for
2338 Crop the input video to given dimensions.
2340 The filter accepts the following options:
2344 Width of the output video. It defaults to @code{iw}.
2345 This expression is evaluated only once during the filter
2349 Height of the output video. It defaults to @code{ih}.
2350 This expression is evaluated only once during the filter
2354 Horizontal position, in the input video, of the left edge of the output video.
2355 It defaults to @code{(in_w-out_w)/2}.
2356 This expression is evaluated per-frame.
2359 Vertical position, in the input video, of the top edge of the output video.
2360 It defaults to @code{(in_h-out_h)/2}.
2361 This expression is evaluated per-frame.
2364 If set to 1 will force the output display aspect ratio
2365 to be the same of the input, by changing the output sample aspect
2366 ratio. It defaults to 0.
2369 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
2370 expressions containing the following constants:
2375 the computed values for @var{x} and @var{y}. They are evaluated for
2380 the input width and height
2384 same as @var{in_w} and @var{in_h}
2388 the output (cropped) width and height
2392 same as @var{out_w} and @var{out_h}
2395 same as @var{iw} / @var{ih}
2398 input sample aspect ratio
2401 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
2405 horizontal and vertical chroma subsample values. For example for the
2406 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2409 the number of input frame, starting from 0
2412 the position in the file of the input frame, NAN if unknown
2415 timestamp expressed in seconds, NAN if the input timestamp is unknown
2419 The expression for @var{out_w} may depend on the value of @var{out_h},
2420 and the expression for @var{out_h} may depend on @var{out_w}, but they
2421 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
2422 evaluated after @var{out_w} and @var{out_h}.
2424 The @var{x} and @var{y} parameters specify the expressions for the
2425 position of the top-left corner of the output (non-cropped) area. They
2426 are evaluated for each frame. If the evaluated value is not valid, it
2427 is approximated to the nearest valid value.
2429 The expression for @var{x} may depend on @var{y}, and the expression
2430 for @var{y} may depend on @var{x}.
2432 @subsection Examples
2436 Crop area with size 100x100 at position (12,34).
2441 Using named options, the example above becomes:
2443 crop=w=100:h=100:x=12:y=34
2447 Crop the central input area with size 100x100:
2453 Crop the central input area with size 2/3 of the input video:
2455 crop=2/3*in_w:2/3*in_h
2459 Crop the input video central square:
2466 Delimit the rectangle with the top-left corner placed at position
2467 100:100 and the right-bottom corner corresponding to the right-bottom
2468 corner of the input image:
2470 crop=in_w-100:in_h-100:100:100
2474 Crop 10 pixels from the left and right borders, and 20 pixels from
2475 the top and bottom borders
2477 crop=in_w-2*10:in_h-2*20
2481 Keep only the bottom right quarter of the input image:
2483 crop=in_w/2:in_h/2:in_w/2:in_h/2
2487 Crop height for getting Greek harmony:
2489 crop=in_w:1/PHI*in_w
2493 Appply trembling effect:
2495 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)
2499 Apply erratic camera effect depending on timestamp:
2501 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)"
2505 Set x depending on the value of y:
2507 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
2513 Auto-detect crop size.
2515 Calculate necessary cropping parameters and prints the recommended
2516 parameters through the logging system. The detected dimensions
2517 correspond to the non-black area of the input video.
2519 The filter accepts the following options:
2524 Set higher black value threshold, which can be optionally specified
2525 from nothing (0) to everything (255). An intensity value greater
2526 to the set value is considered non-black. Default value is 24.
2529 Set the value for which the width/height should be divisible by. The
2530 offset is automatically adjusted to center the video. Use 2 to get
2531 only even dimensions (needed for 4:2:2 video). 16 is best when
2532 encoding to most video codecs. Default value is 16.
2534 @item reset_count, reset
2535 Set the counter that determines after how many frames cropdetect will
2536 reset the previously detected largest video area and start over to
2537 detect the current optimal crop area. Default value is 0.
2539 This can be useful when channel logos distort the video area. 0
2540 indicates never reset and return the largest area encountered during
2547 Apply color adjustments using curves.
2549 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
2550 component (red, green and blue) has its values defined by @var{N} key points
2551 tied from each other using a smooth curve. The x-axis represents the pixel
2552 values from the input frame, and the y-axis the new pixel values to be set for
2555 By default, a component curve is defined by the two points @var{(0;0)} and
2556 @var{(1;1)}. This creates a straight line where each original pixel value is
2557 "adjusted" to its own value, which means no change to the image.
2559 The filter allows you to redefine these two points and add some more. A new
2560 curve (using a natural cubic spline interpolation) will be define to pass
2561 smoothly through all these new coordinates. The new defined points needs to be
2562 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
2563 be in the @var{[0;1]} interval. If the computed curves happened to go outside
2564 the vector spaces, the values will be clipped accordingly.
2566 If there is no key point defined in @code{x=0}, the filter will automatically
2567 insert a @var{(0;0)} point. In the same way, if there is no key point defined
2568 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
2570 The filter accepts the following options:
2574 Select one of the available color presets. This option can be used in addition
2575 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
2576 options takes priority on the preset values.
2577 Available presets are:
2580 @item color_negative
2583 @item increase_contrast
2585 @item linear_contrast
2586 @item medium_contrast
2588 @item strong_contrast
2591 Default is @code{none}.
2593 Set the master key points. These points will define a second pass mapping. It
2594 is sometimes called a "luminance" or "value" mapping. It can be used with
2595 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
2596 post-processing LUT.
2598 Set the key points for the red component.
2600 Set the key points for the green component.
2602 Set the key points for the blue component.
2604 Set the key points for all components (not including master).
2605 Can be used in addition to the other key points component
2606 options. In this case, the unset component(s) will fallback on this
2607 @option{all} setting.
2609 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
2612 To avoid some filtergraph syntax conflicts, each key points list need to be
2613 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
2615 @subsection Examples
2619 Increase slightly the middle level of blue:
2621 curves=blue='0.5/0.58'
2627 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
2629 Here we obtain the following coordinates for each components:
2632 @code{(0;0.11) (0.42;0.51) (1;0.95)}
2634 @code{(0;0) (0.50;0.48) (1;1)}
2636 @code{(0;0.22) (0.49;0.44) (1;0.80)}
2640 The previous example can also be achieved with the associated built-in preset:
2642 curves=preset=vintage
2652 Use a Photoshop preset and redefine the points of the green component:
2654 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
2660 Denoise frames using 2D DCT (frequency domain filtering).
2662 This filter is not designed for real time and can be extremely slow.
2664 The filter accepts the following options:
2668 Set the noise sigma constant.
2670 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
2671 coefficient (absolute value) below this threshold with be dropped.
2673 If you need a more advanced filtering, see @option{expr}.
2675 Default is @code{0}.
2678 Set number overlapping pixels for each block. Each block is of size
2679 @code{16x16}. Since the filter can be slow, you may want to reduce this value,
2680 at the cost of a less effective filter and the risk of various artefacts.
2682 If the overlapping value doesn't allow to process the whole input width or
2683 height, a warning will be displayed and according borders won't be denoised.
2685 Default value is @code{15}.
2688 Set the coefficient factor expression.
2690 For each coefficient of a DCT block, this expression will be evaluated as a
2691 multiplier value for the coefficient.
2693 If this is option is set, the @option{sigma} option will be ignored.
2695 The absolute value of the coefficient can be accessed through the @var{c}
2699 @subsection Examples
2701 Apply a denoise with a @option{sigma} of @code{4.5}:
2706 The same operation can be achieved using the expression system:
2708 dctdnoiz=e='gte(c, 4.5*3)'
2714 Drop duplicated frames at regular intervals.
2716 The filter accepts the following options:
2720 Set the number of frames from which one will be dropped. Setting this to
2721 @var{N} means one frame in every batch of @var{N} frames will be dropped.
2722 Default is @code{5}.
2725 Set the threshold for duplicate detection. If the difference metric for a frame
2726 is less than or equal to this value, then it is declared as duplicate. Default
2730 Set scene change threshold. Default is @code{15}.
2734 Set the size of the x and y-axis blocks used during metric calculations.
2735 Larger blocks give better noise suppression, but also give worse detection of
2736 small movements. Must be a power of two. Default is @code{32}.
2739 Mark main input as a pre-processed input and activate clean source input
2740 stream. This allows the input to be pre-processed with various filters to help
2741 the metrics calculation while keeping the frame selection lossless. When set to
2742 @code{1}, the first stream is for the pre-processed input, and the second
2743 stream is the clean source from where the kept frames are chosen. Default is
2747 Set whether or not chroma is considered in the metric calculations. Default is
2753 Suppress a TV station logo by a simple interpolation of the surrounding
2754 pixels. Just set a rectangle covering the logo and watch it disappear
2755 (and sometimes something even uglier appear - your mileage may vary).
2757 This filter accepts the following options:
2762 Specify the top left corner coordinates of the logo. They must be
2767 Specify the width and height of the logo to clear. They must be
2771 Specify the thickness of the fuzzy edge of the rectangle (added to
2772 @var{w} and @var{h}). The default value is 4.
2775 When set to 1, a green rectangle is drawn on the screen to simplify
2776 finding the right @var{x}, @var{y}, @var{w}, @var{h} parameters, and
2777 @var{band} is set to 4. The default value is 0.
2781 @subsection Examples
2785 Set a rectangle covering the area with top left corner coordinates 0,0
2786 and size 100x77, setting a band of size 10:
2788 delogo=x=0:y=0:w=100:h=77:band=10
2795 Attempt to fix small changes in horizontal and/or vertical shift. This
2796 filter helps remove camera shake from hand-holding a camera, bumping a
2797 tripod, moving on a vehicle, etc.
2799 The filter accepts the following options:
2807 Specify a rectangular area where to limit the search for motion
2809 If desired the search for motion vectors can be limited to a
2810 rectangular area of the frame defined by its top left corner, width
2811 and height. These parameters have the same meaning as the drawbox
2812 filter which can be used to visualise the position of the bounding
2815 This is useful when simultaneous movement of subjects within the frame
2816 might be confused for camera motion by the motion vector search.
2818 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
2819 then the full frame is used. This allows later options to be set
2820 without specifying the bounding box for the motion vector search.
2822 Default - search the whole frame.
2826 Specify the maximum extent of movement in x and y directions in the
2827 range 0-64 pixels. Default 16.
2830 Specify how to generate pixels to fill blanks at the edge of the
2831 frame. Available values are:
2834 Fill zeroes at blank locations
2836 Original image at blank locations
2838 Extruded edge value at blank locations
2840 Mirrored edge at blank locations
2842 Default value is @samp{mirror}.
2845 Specify the blocksize to use for motion search. Range 4-128 pixels,
2849 Specify the contrast threshold for blocks. Only blocks with more than
2850 the specified contrast (difference between darkest and lightest
2851 pixels) will be considered. Range 1-255, default 125.
2854 Specify the search strategy. Available values are:
2857 Set exhaustive search
2859 Set less exhaustive search.
2861 Default value is @samp{exhaustive}.
2864 If set then a detailed log of the motion search is written to the
2868 If set to 1, specify using OpenCL capabilities, only available if
2869 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
2875 Draw a colored box on the input image.
2877 This filter accepts the following options:
2882 Specify the top left corner coordinates of the box. Default to 0.
2886 Specify the width and height of the box, if 0 they are interpreted as
2887 the input width and height. Default to 0.
2890 Specify the color of the box to write, it can be the name of a color
2891 (case insensitive match) or a 0xRRGGBB[AA] sequence. If the special
2892 value @code{invert} is used, the box edge color is the same as the
2893 video with inverted luma.
2896 Set the thickness of the box edge. Default value is @code{4}.
2899 @subsection Examples
2903 Draw a black box around the edge of the input image:
2909 Draw a box with color red and an opacity of 50%:
2911 drawbox=10:20:200:60:red@@0.5
2914 The previous example can be specified as:
2916 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
2920 Fill the box with pink color:
2922 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
2928 Draw a grid on the input image.
2930 This filter accepts the following options:
2935 Specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
2939 Specify the width and height of the grid cell, if 0 they are interpreted as the
2940 input width and height, respectively, minus @code{thickness}, so image gets
2941 framed. Default to 0.
2944 Specify the color of the grid, it can be the name of a color
2945 (case insensitive match) or a 0xRRGGBB[AA] sequence. If the special
2946 value @code{invert} is used, the grid color is the same as the
2947 video with inverted luma.
2948 Note that you can append opacity value (in range of 0.0 - 1.0)
2949 to color name after @@ sign.
2952 Set the thickness of the grid line. Default value is @code{1}.
2955 @subsection Examples
2959 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
2961 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
2968 Draw text string or text from specified file on top of video using the
2969 libfreetype library.
2971 To enable compilation of this filter you need to configure FFmpeg with
2972 @code{--enable-libfreetype}.
2976 The description of the accepted parameters follows.
2981 Used to draw a box around text using background color.
2982 Value should be either 1 (enable) or 0 (disable).
2983 The default value of @var{box} is 0.
2986 The color to be used for drawing box around text.
2987 Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
2988 (e.g. "0xff00ff"), possibly followed by an alpha specifier.
2989 The default value of @var{boxcolor} is "white".
2992 Set an expression which specifies if the text should be drawn. If the
2993 expression evaluates to 0, the text is not drawn. This is useful for
2994 specifying that the text should be drawn only when specific conditions
2997 Default value is "1".
2999 See below for the list of accepted constants and functions.
3002 Select how the @var{text} is expanded. Can be either @code{none},
3003 @code{strftime} (deprecated) or
3004 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3008 If true, check and fix text coords to avoid clipping.
3011 The color to be used for drawing fonts.
3012 Either a string (e.g. "red") or in 0xRRGGBB[AA] format
3013 (e.g. "0xff000033"), possibly followed by an alpha specifier.
3014 The default value of @var{fontcolor} is "black".
3017 The font file to be used for drawing text. Path must be included.
3018 This parameter is mandatory.
3021 The font size to be used for drawing text.
3022 The default value of @var{fontsize} is 16.
3025 Flags to be used for loading the fonts.
3027 The flags map the corresponding flags supported by libfreetype, and are
3028 a combination of the following values:
3035 @item vertical_layout
3036 @item force_autohint
3039 @item ignore_global_advance_width
3041 @item ignore_transform
3047 Default value is "render".
3049 For more information consult the documentation for the FT_LOAD_*
3053 The color to be used for drawing a shadow behind the drawn text. It
3054 can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
3055 form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
3056 The default value of @var{shadowcolor} is "black".
3060 The x and y offsets for the text shadow position with respect to the
3061 position of the text. They can be either positive or negative
3062 values. Default value for both is "0".
3065 The size in number of spaces to use for rendering the tab.
3069 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3070 format. It can be used with or without text parameter. @var{timecode_rate}
3071 option must be specified.
3073 @item timecode_rate, rate, r
3074 Set the timecode frame rate (timecode only).
3077 The text string to be drawn. The text must be a sequence of UTF-8
3079 This parameter is mandatory if no file is specified with the parameter
3083 A text file containing text to be drawn. The text must be a sequence
3084 of UTF-8 encoded characters.
3086 This parameter is mandatory if no text string is specified with the
3087 parameter @var{text}.
3089 If both @var{text} and @var{textfile} are specified, an error is thrown.
3092 If set to 1, the @var{textfile} will be reloaded before each frame.
3093 Be sure to update it atomically, or it may be read partially, or even fail.
3097 The expressions which specify the offsets where text will be drawn
3098 within the video frame. They are relative to the top/left border of the
3101 The default value of @var{x} and @var{y} is "0".
3103 See below for the list of accepted constants and functions.
3106 The parameters for @var{x} and @var{y} are expressions containing the
3107 following constants and functions:
3111 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3115 horizontal and vertical chroma subsample values. For example for the
3116 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3119 the height of each text line
3127 @item max_glyph_a, ascent
3128 the maximum distance from the baseline to the highest/upper grid
3129 coordinate used to place a glyph outline point, for all the rendered
3131 It is a positive value, due to the grid's orientation with the Y axis
3134 @item max_glyph_d, descent
3135 the maximum distance from the baseline to the lowest grid coordinate
3136 used to place a glyph outline point, for all the rendered glyphs.
3137 This is a negative value, due to the grid's orientation, with the Y axis
3141 maximum glyph height, that is the maximum height for all the glyphs
3142 contained in the rendered text, it is equivalent to @var{ascent} -
3146 maximum glyph width, that is the maximum width for all the glyphs
3147 contained in the rendered text
3150 the number of input frame, starting from 0
3152 @item rand(min, max)
3153 return a random number included between @var{min} and @var{max}
3156 input sample aspect ratio
3159 timestamp expressed in seconds, NAN if the input timestamp is unknown
3162 the height of the rendered text
3165 the width of the rendered text
3169 the x and y offset coordinates where the text is drawn.
3171 These parameters allow the @var{x} and @var{y} expressions to refer
3172 each other, so you can for example specify @code{y=x/dar}.
3175 If libavfilter was built with @code{--enable-fontconfig}, then
3176 @option{fontfile} can be a fontconfig pattern or omitted.
3178 @anchor{drawtext_expansion}
3179 @subsection Text expansion
3181 If @option{expansion} is set to @code{strftime},
3182 the filter recognizes strftime() sequences in the provided text and
3183 expands them accordingly. Check the documentation of strftime(). This
3184 feature is deprecated.
3186 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3188 If @option{expansion} is set to @code{normal} (which is the default),
3189 the following expansion mechanism is used.
3191 The backslash character '\', followed by any character, always expands to
3192 the second character.
3194 Sequence of the form @code{%@{...@}} are expanded. The text between the
3195 braces is a function name, possibly followed by arguments separated by ':'.
3196 If the arguments contain special characters or delimiters (':' or '@}'),
3197 they should be escaped.
3199 Note that they probably must also be escaped as the value for the
3200 @option{text} option in the filter argument string and as the filter
3201 argument in the filtergraph description, and possibly also for the shell,
3202 that makes up to four levels of escaping; using a text file avoids these
3205 The following functions are available:
3210 The expression evaluation result.
3212 It must take one argument specifying the expression to be evaluated,
3213 which accepts the same constants and functions as the @var{x} and
3214 @var{y} values. Note that not all constants should be used, for
3215 example the text size is not known when evaluating the expression, so
3216 the constants @var{text_w} and @var{text_h} will have an undefined
3220 The time at which the filter is running, expressed in UTC.
3221 It can accept an argument: a strftime() format string.
3224 The time at which the filter is running, expressed in the local time zone.
3225 It can accept an argument: a strftime() format string.
3228 The frame number, starting from 0.
3231 A 1 character description of the current picture type.
3234 The timestamp of the current frame, in seconds, with microsecond accuracy.
3238 @subsection Examples
3242 Draw "Test Text" with font FreeSerif, using the default values for the
3243 optional parameters.
3246 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
3250 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
3251 and y=50 (counting from the top-left corner of the screen), text is
3252 yellow with a red box around it. Both the text and the box have an
3256 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
3257 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
3260 Note that the double quotes are not necessary if spaces are not used
3261 within the parameter list.
3264 Show the text at the center of the video frame:
3266 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
3270 Show a text line sliding from right to left in the last row of the video
3271 frame. The file @file{LONG_LINE} is assumed to contain a single line
3274 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
3278 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
3280 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
3284 Draw a single green letter "g", at the center of the input video.
3285 The glyph baseline is placed at half screen height.
3287 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
3291 Show text for 1 second every 3 seconds:
3293 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:draw=lt(mod(t\,3)\,1):text='blink'"
3297 Use fontconfig to set the font. Note that the colons need to be escaped.
3299 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
3303 Print the date of a real-time encoding (see strftime(3)):
3305 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
3310 For more information about libfreetype, check:
3311 @url{http://www.freetype.org/}.
3313 For more information about fontconfig, check:
3314 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
3318 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
3320 The filter accepts the following options:
3325 Set low and high threshold values used by the Canny thresholding
3328 The high threshold selects the "strong" edge pixels, which are then
3329 connected through 8-connectivity with the "weak" edge pixels selected
3330 by the low threshold.
3332 @var{low} and @var{high} threshold values must be choosen in the range
3333 [0,1], and @var{low} should be lesser or equal to @var{high}.
3335 Default value for @var{low} is @code{20/255}, and default value for @var{high}
3341 edgedetect=low=0.1:high=0.4
3344 @section extractplanes
3346 Extract color channel components from input video stream into
3347 separate grayscale video streams.
3349 The filter accepts the following option:
3353 Set plane(s) to extract.
3355 Available values for planes are:
3366 Choosing planes not available in the input will result in an error.
3367 That means you cannot select @code{r}, @code{g}, @code{b} planes
3368 with @code{y}, @code{u}, @code{v} planes at same time.
3371 @subsection Examples
3375 Extract luma, u and v color channel component from input video frame
3376 into 3 grayscale outputs:
3378 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
3384 Apply fade-in/out effect to input video.
3386 This filter accepts the following options:
3390 The effect type -- can be either "in" for fade-in, or "out" for a fade-out
3392 Default is @code{in}.
3394 @item start_frame, s
3395 Specify the number of the start frame for starting to apply the fade
3396 effect. Default is 0.
3399 The number of frames for which the fade effect has to last. At the end of the
3400 fade-in effect the output video will have the same intensity as the input video,
3401 at the end of the fade-out transition the output video will be completely black.
3405 If set to 1, fade only alpha channel, if one exists on the input.
3408 @item start_time, st
3409 Specify the timestamp (in seconds) of the frame to start to apply the fade
3410 effect. If both start_frame and start_time are specified, the fade will start at
3411 whichever comes last. Default is 0.
3414 The number of seconds for which the fade effect has to last. At the end of the
3415 fade-in effect the output video will have the same intensity as the input video,
3416 at the end of the fade-out transition the output video will be completely black.
3417 If both duration and nb_frames are specified, duration is used. Default is 0.
3420 @subsection Examples
3424 Fade in first 30 frames of video:
3429 The command above is equivalent to:
3435 Fade out last 45 frames of a 200-frame video:
3438 fade=type=out:start_frame=155:nb_frames=45
3442 Fade in first 25 frames and fade out last 25 frames of a 1000-frame video:
3444 fade=in:0:25, fade=out:975:25
3448 Make first 5 frames black, then fade in from frame 5-24:
3454 Fade in alpha over first 25 frames of video:
3456 fade=in:0:25:alpha=1
3460 Make first 5.5 seconds black, then fade in for 0.5 seconds:
3462 fade=t=in:st=5.5:d=0.5
3469 Extract a single field from an interlaced image using stride
3470 arithmetic to avoid wasting CPU time. The output frames are marked as
3473 The filter accepts the following options:
3477 Specify whether to extract the top (if the value is @code{0} or
3478 @code{top}) or the bottom field (if the value is @code{1} or
3484 Field matching filter for inverse telecine. It is meant to reconstruct the
3485 progressive frames from a telecined stream. The filter does not drop duplicated
3486 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
3487 followed by a decimation filter such as @ref{decimate} in the filtergraph.
3489 The separation of the field matching and the decimation is notably motivated by
3490 the possibility of inserting a de-interlacing filter fallback between the two.
3491 If the source has mixed telecined and real interlaced content,
3492 @code{fieldmatch} will not be able to match fields for the interlaced parts.
3493 But these remaining combed frames will be marked as interlaced, and thus can be
3494 de-interlaced by a later filter such as @ref{yadif} before decimation.
3496 In addition to the various configuration options, @code{fieldmatch} can take an
3497 optional second stream, activated through the @option{ppsrc} option. If
3498 enabled, the frames reconstruction will be based on the fields and frames from
3499 this second stream. This allows the first input to be pre-processed in order to
3500 help the various algorithms of the filter, while keeping the output lossless
3501 (assuming the fields are matched properly). Typically, a field-aware denoiser,
3502 or brightness/contrast adjustments can help.
3504 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
3505 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
3506 which @code{fieldmatch} is based on. While the semantic and usage are very
3507 close, some behaviour and options names can differ.
3509 The filter accepts the following options:
3513 Specify the assumed field order of the input stream. Available values are:
3517 Auto detect parity (use FFmpeg's internal parity value).
3519 Assume bottom field first.
3521 Assume top field first.
3524 Note that it is sometimes recommended not to trust the parity announced by the
3527 Default value is @var{auto}.
3530 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
3531 sense that it wont risk creating jerkiness due to duplicate frames when
3532 possible, but if there are bad edits or blended fields it will end up
3533 outputting combed frames when a good match might actually exist. On the other
3534 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
3535 but will almost always find a good frame if there is one. The other values are
3536 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
3537 jerkiness and creating duplicate frames versus finding good matches in sections
3538 with bad edits, orphaned fields, blended fields, etc.
3540 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
3542 Available values are:
3546 2-way matching (p/c)
3548 2-way matching, and trying 3rd match if still combed (p/c + n)
3550 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
3552 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
3553 still combed (p/c + n + u/b)
3555 3-way matching (p/c/n)
3557 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
3558 detected as combed (p/c/n + u/b)
3561 The parenthesis at the end indicate the matches that would be used for that
3562 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
3565 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
3568 Default value is @var{pc_n}.
3571 Mark the main input stream as a pre-processed input, and enable the secondary
3572 input stream as the clean source to pick the fields from. See the filter
3573 introduction for more details. It is similar to the @option{clip2} feature from
3576 Default value is @code{0} (disabled).
3579 Set the field to match from. It is recommended to set this to the same value as
3580 @option{order} unless you experience matching failures with that setting. In
3581 certain circumstances changing the field that is used to match from can have a
3582 large impact on matching performance. Available values are:
3586 Automatic (same value as @option{order}).
3588 Match from the bottom field.
3590 Match from the top field.
3593 Default value is @var{auto}.
3596 Set whether or not chroma is included during the match comparisons. In most
3597 cases it is recommended to leave this enabled. You should set this to @code{0}
3598 only if your clip has bad chroma problems such as heavy rainbowing or other
3599 artifacts. Setting this to @code{0} could also be used to speed things up at
3600 the cost of some accuracy.
3602 Default value is @code{1}.
3606 These define an exclusion band which excludes the lines between @option{y0} and
3607 @option{y1} from being included in the field matching decision. An exclusion
3608 band can be used to ignore subtitles, a logo, or other things that may
3609 interfere with the matching. @option{y0} sets the starting scan line and
3610 @option{y1} sets the ending line; all lines in between @option{y0} and
3611 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
3612 @option{y0} and @option{y1} to the same value will disable the feature.
3613 @option{y0} and @option{y1} defaults to @code{0}.
3616 Set the scene change detection threshold as a percentage of maximum change on
3617 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
3618 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
3619 @option{scthresh} is @code{[0.0, 100.0]}.
3621 Default value is @code{12.0}.
3624 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
3625 account the combed scores of matches when deciding what match to use as the
3626 final match. Available values are:
3630 No final matching based on combed scores.
3632 Combed scores are only used when a scene change is detected.
3634 Use combed scores all the time.
3637 Default is @var{sc}.
3640 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
3641 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
3642 Available values are:
3646 No forced calculation.
3648 Force p/c/n calculations.
3650 Force p/c/n/u/b calculations.
3653 Default value is @var{none}.
3656 This is the area combing threshold used for combed frame detection. This
3657 essentially controls how "strong" or "visible" combing must be to be detected.
3658 Larger values mean combing must be more visible and smaller values mean combing
3659 can be less visible or strong and still be detected. Valid settings are from
3660 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
3661 be detected as combed). This is basically a pixel difference value. A good
3662 range is @code{[8, 12]}.
3664 Default value is @code{9}.
3667 Sets whether or not chroma is considered in the combed frame decision. Only
3668 disable this if your source has chroma problems (rainbowing, etc.) that are
3669 causing problems for the combed frame detection with chroma enabled. Actually,
3670 using @option{chroma}=@var{0} is usually more reliable, except for the case
3671 where there is chroma only combing in the source.
3673 Default value is @code{0}.
3677 Respectively set the x-axis and y-axis size of the window used during combed
3678 frame detection. This has to do with the size of the area in which
3679 @option{combpel} pixels are required to be detected as combed for a frame to be
3680 declared combed. See the @option{combpel} parameter description for more info.
3681 Possible values are any number that is a power of 2 starting at 4 and going up
3684 Default value is @code{16}.
3687 The number of combed pixels inside any of the @option{blocky} by
3688 @option{blockx} size blocks on the frame for the frame to be detected as
3689 combed. While @option{cthresh} controls how "visible" the combing must be, this
3690 setting controls "how much" combing there must be in any localized area (a
3691 window defined by the @option{blockx} and @option{blocky} settings) on the
3692 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
3693 which point no frames will ever be detected as combed). This setting is known
3694 as @option{MI} in TFM/VFM vocabulary.
3696 Default value is @code{80}.
3699 @anchor{p/c/n/u/b meaning}
3700 @subsection p/c/n/u/b meaning
3702 @subsubsection p/c/n
3704 We assume the following telecined stream:
3707 Top fields: 1 2 2 3 4
3708 Bottom fields: 1 2 3 4 4
3711 The numbers correspond to the progressive frame the fields relate to. Here, the
3712 first two frames are progressive, the 3rd and 4th are combed, and so on.
3714 When @code{fieldmatch} is configured to run a matching from bottom
3715 (@option{field}=@var{bottom}) this is how this input stream get transformed:
3720 B 1 2 3 4 4 <-- matching reference
3729 As a result of the field matching, we can see that some frames get duplicated.
3730 To perform a complete inverse telecine, you need to rely on a decimation filter
3731 after this operation. See for instance the @ref{decimate} filter.
3733 The same operation now matching from top fields (@option{field}=@var{top})
3738 T 1 2 2 3 4 <-- matching reference
3748 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
3749 basically, they refer to the frame and field of the opposite parity:
3752 @item @var{p} matches the field of the opposite parity in the previous frame
3753 @item @var{c} matches the field of the opposite parity in the current frame
3754 @item @var{n} matches the field of the opposite parity in the next frame
3759 The @var{u} and @var{b} matching are a bit special in the sense that they match
3760 from the opposite parity flag. In the following examples, we assume that we are
3761 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
3762 'x' is placed above and below each matched fields.
3764 With bottom matching (@option{field}=@var{bottom}):
3769 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
3770 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
3778 With top matching (@option{field}=@var{top}):
3783 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
3784 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
3792 @subsection Examples
3794 Simple IVTC of a top field first telecined stream:
3796 fieldmatch=order=tff:combmatch=none, decimate
3799 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
3801 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
3806 Transform the field order of the input video.
3808 This filter accepts the following options:
3813 Output field order. Valid values are @var{tff} for top field first or @var{bff}
3814 for bottom field first.
3817 Default value is @samp{tff}.
3819 Transformation is achieved by shifting the picture content up or down
3820 by one line, and filling the remaining line with appropriate picture content.
3821 This method is consistent with most broadcast field order converters.
3823 If the input video is not flagged as being interlaced, or it is already
3824 flagged as being of the required output field order then this filter does
3825 not alter the incoming video.
3827 This filter is very useful when converting to or from PAL DV material,
3828 which is bottom field first.
3832 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
3837 Buffer input images and send them when they are requested.
3839 This filter is mainly useful when auto-inserted by the libavfilter
3842 The filter does not take parameters.
3847 Convert the input video to one of the specified pixel formats.
3848 Libavfilter will try to pick one that is supported for the input to
3851 This filter accepts the following parameters:
3855 A '|'-separated list of pixel format names, for example
3856 "pix_fmts=yuv420p|monow|rgb24".
3860 @subsection Examples
3864 Convert the input video to the format @var{yuv420p}
3866 format=pix_fmts=yuv420p
3869 Convert the input video to any of the formats in the list
3871 format=pix_fmts=yuv420p|yuv444p|yuv410p
3877 Convert the video to specified constant frame rate by duplicating or dropping
3878 frames as necessary.
3880 This filter accepts the following named parameters:
3884 Desired output frame rate. The default is @code{25}.
3889 Possible values are:
3892 zero round towards 0
3896 round towards -infinity
3898 round towards +infinity
3902 The default is @code{near}.
3906 Alternatively, the options can be specified as a flat string:
3907 @var{fps}[:@var{round}].
3909 See also the @ref{setpts} filter.
3911 @subsection Examples
3915 A typical usage in order to set the fps to 25:
3921 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
3923 fps=fps=film:round=near
3929 Select one frame every N-th frame.
3931 This filter accepts the following option:
3934 Select frame after every @code{step} frames.
3935 Allowed values are positive integers higher than 0. Default value is @code{1}.
3941 Apply a frei0r effect to the input video.
3943 To enable compilation of this filter you need to install the frei0r
3944 header and configure FFmpeg with @code{--enable-frei0r}.
3946 This filter accepts the following options:
3951 The name to the frei0r effect to load. If the environment variable
3952 @env{FREI0R_PATH} is defined, the frei0r effect is searched in each one of the
3953 directories specified by the colon separated list in @env{FREIOR_PATH},
3954 otherwise in the standard frei0r paths, which are in this order:
3955 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
3956 @file{/usr/lib/frei0r-1/}.
3959 A '|'-separated list of parameters to pass to the frei0r effect.
3963 A frei0r effect parameter can be a boolean (whose values are specified
3964 with "y" and "n"), a double, a color (specified by the syntax
3965 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
3966 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
3967 description), a position (specified by the syntax @var{X}/@var{Y},
3968 @var{X} and @var{Y} being float numbers) and a string.
3970 The number and kind of parameters depend on the loaded effect. If an
3971 effect parameter is not specified the default value is set.
3973 @subsection Examples
3977 Apply the distort0r effect, set the first two double parameters:
3979 frei0r=filter_name=distort0r:filter_params=0.5|0.01
3983 Apply the colordistance effect, take a color as first parameter:
3985 frei0r=colordistance:0.2/0.3/0.4
3986 frei0r=colordistance:violet
3987 frei0r=colordistance:0x112233
3991 Apply the perspective effect, specify the top left and top right image
3994 frei0r=perspective:0.2/0.2|0.8/0.2
3998 For more information see:
3999 @url{http://frei0r.dyne.org}
4003 The filter accepts the following options:
4007 Set the luminance expression.
4009 Set the chrominance blue expression.
4011 Set the chrominance red expression.
4013 Set the alpha expression.
4015 Set the red expression.
4017 Set the green expression.
4019 Set the blue expression.
4022 The colorspace is selected according to the specified options. If one
4023 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4024 options is specified, the filter will automatically select a YCbCr
4025 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4026 @option{blue_expr} options is specified, it will select an RGB
4029 If one of the chrominance expression is not defined, it falls back on the other
4030 one. If no alpha expression is specified it will evaluate to opaque value.
4031 If none of chrominance expressions are specified, they will evaluate
4032 to the luminance expression.
4034 The expressions can use the following variables and functions:
4038 The sequential number of the filtered frame, starting from @code{0}.
4042 The coordinates of the current sample.
4046 The width and height of the image.
4050 Width and height scale depending on the currently filtered plane. It is the
4051 ratio between the corresponding luma plane number of pixels and the current
4052 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4053 @code{0.5,0.5} for chroma planes.
4056 Time of the current frame, expressed in seconds.
4059 Return the value of the pixel at location (@var{x},@var{y}) of the current
4063 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
4067 Return the value of the pixel at location (@var{x},@var{y}) of the
4068 blue-difference chroma plane. Return 0 if there is no such plane.
4071 Return the value of the pixel at location (@var{x},@var{y}) of the
4072 red-difference chroma plane. Return 0 if there is no such plane.
4077 Return the value of the pixel at location (@var{x},@var{y}) of the
4078 red/green/blue component. Return 0 if there is no such component.
4081 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
4082 plane. Return 0 if there is no such plane.
4085 For functions, if @var{x} and @var{y} are outside the area, the value will be
4086 automatically clipped to the closer edge.
4088 @subsection Examples
4092 Flip the image horizontally:
4098 Generate a bidimensional sine wave, with angle @code{PI/3} and a
4099 wavelength of 100 pixels:
4101 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
4105 Generate a fancy enigmatic moving light:
4107 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
4111 Generate a quick emboss effect:
4113 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
4117 Modify RGB components depending on pixel position:
4119 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
4125 Fix the banding artifacts that are sometimes introduced into nearly flat
4126 regions by truncation to 8bit color depth.
4127 Interpolate the gradients that should go where the bands are, and
4130 This filter is designed for playback only. Do not use it prior to
4131 lossy compression, because compression tends to lose the dither and
4132 bring back the bands.
4134 This filter accepts the following options:
4139 The maximum amount by which the filter will change any one pixel. Also the
4140 threshold for detecting nearly flat regions. Acceptable values range from .51 to
4141 64, default value is 1.2, out-of-range values will be clipped to the valid
4145 The neighborhood to fit the gradient to. A larger radius makes for smoother
4146 gradients, but also prevents the filter from modifying the pixels near detailed
4147 regions. Acceptable values are 8-32, default value is 16, out-of-range values
4148 will be clipped to the valid range.
4152 Alternatively, the options can be specified as a flat string:
4153 @var{strength}[:@var{radius}]
4155 @subsection Examples
4159 Apply the filter with a @code{3.5} strength and radius of @code{8}:
4165 Specify radius, omitting the strength (which will fall-back to the default
4175 Flip the input video horizontally.
4177 For example to horizontally flip the input video with @command{ffmpeg}:
4179 ffmpeg -i in.avi -vf "hflip" out.avi
4183 This filter applies a global color histogram equalization on a
4186 It can be used to correct video that has a compressed range of pixel
4187 intensities. The filter redistributes the pixel intensities to
4188 equalize their distribution across the intensity range. It may be
4189 viewed as an "automatically adjusting contrast filter". This filter is
4190 useful only for correcting degraded or poorly captured source
4193 The filter accepts the following options:
4197 Determine the amount of equalization to be applied. As the strength
4198 is reduced, the distribution of pixel intensities more-and-more
4199 approaches that of the input frame. The value must be a float number
4200 in the range [0,1] and defaults to 0.200.
4203 Set the maximum intensity that can generated and scale the output
4204 values appropriately. The strength should be set as desired and then
4205 the intensity can be limited if needed to avoid washing-out. The value
4206 must be a float number in the range [0,1] and defaults to 0.210.
4209 Set the antibanding level. If enabled the filter will randomly vary
4210 the luminance of output pixels by a small amount to avoid banding of
4211 the histogram. Possible values are @code{none}, @code{weak} or
4212 @code{strong}. It defaults to @code{none}.
4217 Compute and draw a color distribution histogram for the input video.
4219 The computed histogram is a representation of distribution of color components
4222 The filter accepts the following options:
4228 It accepts the following values:
4231 standard histogram that display color components distribution in an image.
4232 Displays color graph for each color component. Shows distribution
4233 of the Y, U, V, A or G, B, R components, depending on input format,
4234 in current frame. Bellow each graph is color component scale meter.
4237 chroma values in vectorscope, if brighter more such chroma values are
4238 distributed in an image.
4239 Displays chroma values (U/V color placement) in two dimensional graph
4240 (which is called a vectorscope). It can be used to read of the hue and
4241 saturation of the current frame. At a same time it is a histogram.
4242 The whiter a pixel in the vectorscope, the more pixels of the input frame
4243 correspond to that pixel (that is the more pixels have this chroma value).
4244 The V component is displayed on the horizontal (X) axis, with the leftmost
4245 side being V = 0 and the rightmost side being V = 255.
4246 The U component is displayed on the vertical (Y) axis, with the top
4247 representing U = 0 and the bottom representing U = 255.
4249 The position of a white pixel in the graph corresponds to the chroma value
4250 of a pixel of the input clip. So the graph can be used to read of the
4251 hue (color flavor) and the saturation (the dominance of the hue in the color).
4252 As the hue of a color changes, it moves around the square. At the center of
4253 the square, the saturation is zero, which means that the corresponding pixel
4254 has no color. If you increase the amount of a specific color, while leaving
4255 the other colors unchanged, the saturation increases, and you move towards
4256 the edge of the square.
4259 chroma values in vectorscope, similar as @code{color} but actual chroma values
4263 per row/column color component graph. In row mode graph in the left side represents
4264 color component value 0 and right side represents value = 255. In column mode top
4265 side represents color component value = 0 and bottom side represents value = 255.
4267 Default value is @code{levels}.
4270 Set height of level in @code{levels}. Default value is @code{200}.
4271 Allowed range is [50, 2048].
4274 Set height of color scale in @code{levels}. Default value is @code{12}.
4275 Allowed range is [0, 40].
4278 Set step for @code{waveform} mode. Smaller values are useful to find out how much
4279 of same luminance values across input rows/columns are distributed.
4280 Default value is @code{10}. Allowed range is [1, 255].
4283 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
4284 Default is @code{row}.
4287 Set display mode for @code{waveform} and @code{levels}.
4288 It accepts the following values:
4291 Display separate graph for the color components side by side in
4292 @code{row} waveform mode or one below other in @code{column} waveform mode
4293 for @code{waveform} histogram mode. For @code{levels} histogram mode
4294 per color component graphs are placed one bellow other.
4296 This display mode in @code{waveform} histogram mode makes it easy to spot
4297 color casts in the highlights and shadows of an image, by comparing the
4298 contours of the top and the bottom of each waveform.
4299 Since whites, grays, and blacks are characterized by
4300 exactly equal amounts of red, green, and blue, neutral areas of the
4301 picture should display three waveforms of roughly equal width/height.
4302 If not, the correction is easy to make by making adjustments to level the
4306 Presents information that's identical to that in the @code{parade}, except
4307 that the graphs representing color components are superimposed directly
4310 This display mode in @code{waveform} histogram mode can make it easier to spot
4311 the relative differences or similarities in overlapping areas of the color
4312 components that are supposed to be identical, such as neutral whites, grays,
4315 Default is @code{parade}.
4318 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
4319 Default is @code{linear}.
4322 @subsection Examples
4327 Calculate and draw histogram:
4329 ffplay -i input -vf histogram
4337 High precision/quality 3d denoise filter. This filter aims to reduce
4338 image noise producing smooth images and making still images really
4339 still. It should enhance compressibility.
4341 It accepts the following optional parameters:
4345 a non-negative float number which specifies spatial luma strength,
4348 @item chroma_spatial
4349 a non-negative float number which specifies spatial chroma strength,
4350 defaults to 3.0*@var{luma_spatial}/4.0
4353 a float number which specifies luma temporal strength, defaults to
4354 6.0*@var{luma_spatial}/4.0
4357 a float number which specifies chroma temporal strength, defaults to
4358 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
4363 Modify the hue and/or the saturation of the input.
4365 This filter accepts the following options:
4369 Specify the hue angle as a number of degrees. It accepts an expression,
4370 and defaults to "0".
4373 Specify the saturation in the [-10,10] range. It accepts an expression and
4377 Specify the hue angle as a number of radians. It accepts an
4378 expression, and defaults to "0".
4381 @option{h} and @option{H} are mutually exclusive, and can't be
4382 specified at the same time.
4384 The @option{h}, @option{H} and @option{s} option values are
4385 expressions containing the following constants:
4389 frame count of the input frame starting from 0
4392 presentation timestamp of the input frame expressed in time base units
4395 frame rate of the input video, NAN if the input frame rate is unknown
4398 timestamp expressed in seconds, NAN if the input timestamp is unknown
4401 time base of the input video
4404 @subsection Examples
4408 Set the hue to 90 degrees and the saturation to 1.0:
4414 Same command but expressing the hue in radians:
4420 Rotate hue and make the saturation swing between 0
4421 and 2 over a period of 1 second:
4423 hue="H=2*PI*t: s=sin(2*PI*t)+1"
4427 Apply a 3 seconds saturation fade-in effect starting at 0:
4432 The general fade-in expression can be written as:
4434 hue="s=min(0\, max((t-START)/DURATION\, 1))"
4438 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
4440 hue="s=max(0\, min(1\, (8-t)/3))"
4443 The general fade-out expression can be written as:
4445 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
4450 @subsection Commands
4452 This filter supports the following commands:
4457 Modify the hue and/or the saturation of the input video.
4458 The command accepts the same syntax of the corresponding option.
4460 If the specified expression is not valid, it is kept at its current
4466 Detect video interlacing type.
4468 This filter tries to detect if the input is interlaced or progressive,
4469 top or bottom field first.
4471 The filter accepts the following options:
4475 Set interlacing threshold.
4477 Set progressive threshold.
4482 Deinterleave or interleave fields.
4484 This filter allows to process interlaced images fields without
4485 deinterlacing them. Deinterleaving splits the input frame into 2
4486 fields (so called half pictures). Odd lines are moved to the top
4487 half of the output image, even lines to the bottom half.
4488 You can process (filter) them independently and then re-interleave them.
4490 The filter accepts the following options:
4494 @item chroma_mode, s
4496 Available values for @var{luma_mode}, @var{chroma_mode} and
4497 @var{alpha_mode} are:
4503 @item deinterleave, d
4504 Deinterleave fields, placing one above the other.
4507 Interleave fields. Reverse the effect of deinterleaving.
4509 Default value is @code{none}.
4512 @item chroma_swap, cs
4513 @item alpha_swap, as
4514 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
4519 Simple interlacing filter from progressive contents. This interleaves upper (or
4520 lower) lines from odd frames with lower (or upper) lines from even frames,
4521 halving the frame rate and preserving image height.
4524 Original Original New Frame
4525 Frame 'j' Frame 'j+1' (tff)
4526 ========== =========== ==================
4527 Line 0 --------------------> Frame 'j' Line 0
4528 Line 1 Line 1 ----> Frame 'j+1' Line 1
4529 Line 2 ---------------------> Frame 'j' Line 2
4530 Line 3 Line 3 ----> Frame 'j+1' Line 3
4532 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
4535 It accepts the following optional parameters:
4539 determines whether the interlaced frame is taken from the even (tff - default)
4540 or odd (bff) lines of the progressive frame.
4543 Enable (default) or disable the vertical lowpass filter to avoid twitter
4544 interlacing and reduce moire patterns.
4549 Deinterlace input video by applying Donald Graft's adaptive kernel
4550 deinterling. Work on interlaced parts of a video to produce
4553 The description of the accepted parameters follows.
4557 Set the threshold which affects the filter's tolerance when
4558 determining if a pixel line must be processed. It must be an integer
4559 in the range [0,255] and defaults to 10. A value of 0 will result in
4560 applying the process on every pixels.
4563 Paint pixels exceeding the threshold value to white if set to 1.
4567 Set the fields order. Swap fields if set to 1, leave fields alone if
4571 Enable additional sharpening if set to 1. Default is 0.
4574 Enable twoway sharpening if set to 1. Default is 0.
4577 @subsection Examples
4581 Apply default values:
4583 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
4587 Enable additional sharpening:
4593 Paint processed pixels in white:
4601 Apply a 3D LUT to an input video.
4603 The filter accepts the following options:
4607 Set the 3D LUT file name.
4609 Currently supported formats:
4621 Select interpolation mode.
4623 Available values are:
4627 Use values from the nearest defined point.
4629 Interpolate values using the 8 points defining a cube.
4631 Interpolate values using a tetrahedron.
4635 @section lut, lutrgb, lutyuv
4637 Compute a look-up table for binding each pixel component input value
4638 to an output value, and apply it to input video.
4640 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
4641 to an RGB input video.
4643 These filters accept the following options:
4646 set first pixel component expression
4648 set second pixel component expression
4650 set third pixel component expression
4652 set fourth pixel component expression, corresponds to the alpha component
4655 set red component expression
4657 set green component expression
4659 set blue component expression
4661 alpha component expression
4664 set Y/luminance component expression
4666 set U/Cb component expression
4668 set V/Cr component expression
4671 Each of them specifies the expression to use for computing the lookup table for
4672 the corresponding pixel component values.
4674 The exact component associated to each of the @var{c*} options depends on the
4677 The @var{lut} filter requires either YUV or RGB pixel formats in input,
4678 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
4680 The expressions can contain the following constants and functions:
4685 the input width and height
4688 input value for the pixel component
4691 the input value clipped in the @var{minval}-@var{maxval} range
4694 maximum value for the pixel component
4697 minimum value for the pixel component
4700 the negated value for the pixel component value clipped in the
4701 @var{minval}-@var{maxval} range , it corresponds to the expression
4702 "maxval-clipval+minval"
4705 the computed value in @var{val} clipped in the
4706 @var{minval}-@var{maxval} range
4708 @item gammaval(gamma)
4709 the computed gamma correction value of the pixel component value
4710 clipped in the @var{minval}-@var{maxval} range, corresponds to the
4712 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
4716 All expressions default to "val".
4718 @subsection Examples
4724 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
4725 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
4728 The above is the same as:
4730 lutrgb="r=negval:g=negval:b=negval"
4731 lutyuv="y=negval:u=negval:v=negval"
4741 Remove chroma components, turns the video into a graytone image:
4743 lutyuv="u=128:v=128"
4747 Apply a luma burning effect:
4753 Remove green and blue components:
4759 Set a constant alpha channel value on input:
4761 format=rgba,lutrgb=a="maxval-minval/2"
4765 Correct luminance gamma by a 0.5 factor:
4767 lutyuv=y=gammaval(0.5)
4771 Discard least significant bits of luma:
4773 lutyuv=y='bitand(val, 128+64+32)'
4779 Apply an MPlayer filter to the input video.
4781 This filter provides a wrapper around most of the filters of
4784 This wrapper is considered experimental. Some of the wrapped filters
4785 may not work properly and we may drop support for them, as they will
4786 be implemented natively into FFmpeg. Thus you should avoid
4787 depending on them when writing portable scripts.
4789 The filters accepts the parameters:
4790 @var{filter_name}[:=]@var{filter_params}
4792 @var{filter_name} is the name of a supported MPlayer filter,
4793 @var{filter_params} is a string containing the parameters accepted by
4796 The list of the currently supported filters follows:
4816 The parameter syntax and behavior for the listed filters are the same
4817 of the corresponding MPlayer filters. For detailed instructions check
4818 the "VIDEO FILTERS" section in the MPlayer manual.
4820 @subsection Examples
4824 Adjust gamma, brightness, contrast:
4830 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
4834 Drop frames that do not differ greatly from the previous frame in
4835 order to reduce frame rate.
4837 The main use of this filter is for very-low-bitrate encoding
4838 (e.g. streaming over dialup modem), but it could in theory be used for
4839 fixing movies that were inverse-telecined incorrectly.
4841 A description of the accepted options follows.
4845 Set the maximum number of consecutive frames which can be dropped (if
4846 positive), or the minimum interval between dropped frames (if
4847 negative). If the value is 0, the frame is dropped unregarding the
4848 number of previous sequentially dropped frames.
4855 Set the dropping threshold values.
4857 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
4858 represent actual pixel value differences, so a threshold of 64
4859 corresponds to 1 unit of difference for each pixel, or the same spread
4860 out differently over the block.
4862 A frame is a candidate for dropping if no 8x8 blocks differ by more
4863 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
4864 meaning the whole image) differ by more than a threshold of @option{lo}.
4866 Default value for @option{hi} is 64*12, default value for @option{lo} is
4867 64*5, and default value for @option{frac} is 0.33.
4875 This filter accepts an integer in input, if non-zero it negates the
4876 alpha component (if available). The default value in input is 0.
4880 Force libavfilter not to use any of the specified pixel formats for the
4881 input to the next filter.
4883 This filter accepts the following parameters:
4887 A '|'-separated list of pixel format names, for example
4888 "pix_fmts=yuv420p|monow|rgb24".
4892 @subsection Examples
4896 Force libavfilter to use a format different from @var{yuv420p} for the
4897 input to the vflip filter:
4899 noformat=pix_fmts=yuv420p,vflip
4903 Convert the input video to any of the formats not contained in the list:
4905 noformat=yuv420p|yuv444p|yuv410p
4911 Add noise on video input frame.
4913 The filter accepts the following options:
4921 Set noise seed for specific pixel component or all pixel components in case
4922 of @var{all_seed}. Default value is @code{123457}.
4924 @item all_strength, alls
4925 @item c0_strength, c0s
4926 @item c1_strength, c1s
4927 @item c2_strength, c2s
4928 @item c3_strength, c3s
4929 Set noise strength for specific pixel component or all pixel components in case
4930 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
4932 @item all_flags, allf
4937 Set pixel component flags or set flags for all components if @var{all_flags}.
4938 Available values for component flags are:
4941 averaged temporal noise (smoother)
4943 mix random noise with a (semi)regular pattern
4945 temporal noise (noise pattern changes between frames)
4947 uniform noise (gaussian otherwise)
4951 @subsection Examples
4953 Add temporal and uniform noise to input video:
4955 noise=alls=20:allf=t+u
4960 Pass the video source unchanged to the output.
4964 Apply video transform using libopencv.
4966 To enable this filter install libopencv library and headers and
4967 configure FFmpeg with @code{--enable-libopencv}.
4969 This filter accepts the following parameters:
4974 The name of the libopencv filter to apply.
4977 The parameters to pass to the libopencv filter. If not specified the default
4982 Refer to the official libopencv documentation for more precise
4984 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
4986 Follows the list of supported libopencv filters.
4991 Dilate an image by using a specific structuring element.
4992 This filter corresponds to the libopencv function @code{cvDilate}.
4994 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
4996 @var{struct_el} represents a structuring element, and has the syntax:
4997 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
4999 @var{cols} and @var{rows} represent the number of columns and rows of
5000 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
5001 point, and @var{shape} the shape for the structuring element, and
5002 can be one of the values "rect", "cross", "ellipse", "custom".
5004 If the value for @var{shape} is "custom", it must be followed by a
5005 string of the form "=@var{filename}". The file with name
5006 @var{filename} is assumed to represent a binary image, with each
5007 printable character corresponding to a bright pixel. When a custom
5008 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
5009 or columns and rows of the read file are assumed instead.
5011 The default value for @var{struct_el} is "3x3+0x0/rect".
5013 @var{nb_iterations} specifies the number of times the transform is
5014 applied to the image, and defaults to 1.
5016 Follow some example:
5018 # use the default values
5021 # dilate using a structuring element with a 5x5 cross, iterate two times
5022 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
5024 # read the shape from the file diamond.shape, iterate two times
5025 # the file diamond.shape may contain a pattern of characters like this:
5031 # the specified cols and rows are ignored (but not the anchor point coordinates)
5032 ocv=dilate:0x0+2x2/custom=diamond.shape|2
5037 Erode an image by using a specific structuring element.
5038 This filter corresponds to the libopencv function @code{cvErode}.
5040 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
5041 with the same syntax and semantics as the @ref{dilate} filter.
5045 Smooth the input video.
5047 The filter takes the following parameters:
5048 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
5050 @var{type} is the type of smooth filter to apply, and can be one of
5051 the following values: "blur", "blur_no_scale", "median", "gaussian",
5052 "bilateral". The default value is "gaussian".
5054 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
5055 parameters whose meanings depend on smooth type. @var{param1} and
5056 @var{param2} accept integer positive values or 0, @var{param3} and
5057 @var{param4} accept float values.
5059 The default value for @var{param1} is 3, the default value for the
5060 other parameters is 0.
5062 These parameters correspond to the parameters assigned to the
5063 libopencv function @code{cvSmooth}.
5068 Overlay one video on top of another.
5070 It takes two inputs and one output, the first input is the "main"
5071 video on which the second input is overlayed.
5073 This filter accepts the following parameters:
5075 A description of the accepted options follows.
5080 Set the expression for the x and y coordinates of the overlayed video
5081 on the main video. Default value is "0" for both expressions. In case
5082 the expression is invalid, it is set to a huge value (meaning that the
5083 overlay will not be displayed within the output visible area).
5086 Set when the expressions for @option{x}, and @option{y} are evaluated.
5088 It accepts the following values:
5091 only evaluate expressions once during the filter initialization or
5092 when a command is processed
5095 evaluate expressions for each incoming frame
5098 Default value is @samp{frame}.
5101 If set to 1, force the output to terminate when the shortest input
5102 terminates. Default value is 0.
5105 Set the format for the output video.
5107 It accepts the following values:
5119 Default value is @samp{yuv420}.
5121 @item rgb @emph{(deprecated)}
5122 If set to 1, force the filter to accept inputs in the RGB
5123 color space. Default value is 0. This option is deprecated, use
5124 @option{format} instead.
5127 If set to 1, force the filter to draw the last overlay frame over the
5128 main input until the end of the stream. A value of 0 disables this
5129 behavior, which is enabled by default.
5132 The @option{x}, and @option{y} expressions can contain the following
5138 main input width and height
5142 overlay input width and height
5146 the computed values for @var{x} and @var{y}. They are evaluated for
5151 horizontal and vertical chroma subsample values of the output
5152 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
5156 the number of input frame, starting from 0
5159 the position in the file of the input frame, NAN if unknown
5162 timestamp expressed in seconds, NAN if the input timestamp is unknown
5165 Note that the @var{n}, @var{pos}, @var{t} variables are available only
5166 when evaluation is done @emph{per frame}, and will evaluate to NAN
5167 when @option{eval} is set to @samp{init}.
5169 Be aware that frames are taken from each input video in timestamp
5170 order, hence, if their initial timestamps differ, it is a a good idea
5171 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
5172 have them begin in the same zero timestamp, as it does the example for
5173 the @var{movie} filter.
5175 You can chain together more overlays but you should test the
5176 efficiency of such approach.
5178 @subsection Commands
5180 This filter supports the following commands:
5184 Modify the x and y of the overlay input.
5185 The command accepts the same syntax of the corresponding option.
5187 If the specified expression is not valid, it is kept at its current
5191 @subsection Examples
5195 Draw the overlay at 10 pixels from the bottom right corner of the main
5198 overlay=main_w-overlay_w-10:main_h-overlay_h-10
5201 Using named options the example above becomes:
5203 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
5207 Insert a transparent PNG logo in the bottom left corner of the input,
5208 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
5210 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
5214 Insert 2 different transparent PNG logos (second logo on bottom
5215 right corner) using the @command{ffmpeg} tool:
5217 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
5221 Add a transparent color layer on top of the main video, @code{WxH}
5222 must specify the size of the main input to the overlay filter:
5224 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
5228 Play an original video and a filtered version (here with the deshake
5229 filter) side by side using the @command{ffplay} tool:
5231 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
5234 The above command is the same as:
5236 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
5240 Make a sliding overlay appearing from the left to the right top part of the
5241 screen starting since time 2:
5243 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
5247 Compose output by putting two input videos side to side:
5249 ffmpeg -i left.avi -i right.avi -filter_complex "
5250 nullsrc=size=200x100 [background];
5251 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
5252 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
5253 [background][left] overlay=shortest=1 [background+left];
5254 [background+left][right] overlay=shortest=1:x=100 [left+right]
5259 Chain several overlays in cascade:
5261 nullsrc=s=200x200 [bg];
5262 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
5263 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
5264 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
5265 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
5266 [in3] null, [mid2] overlay=100:100 [out0]
5273 Apply Overcomplete Wavelet denoiser.
5275 The filter accepts the following options:
5281 Larger depth values will denoise lower frequency components more, but
5282 slow down filtering.
5284 Must be an int in the range 8-16, default is @code{8}.
5286 @item luma_strength, ls
5289 Must be a double value in the range 0-1000, default is @code{1.0}.
5291 @item chroma_strength, cs
5292 Set chroma strength.
5294 Must be a double value in the range 0-1000, default is @code{1.0}.
5299 Add paddings to the input image, and place the original input at the
5300 given coordinates @var{x}, @var{y}.
5302 This filter accepts the following parameters:
5307 Specify an expression for the size of the output image with the
5308 paddings added. If the value for @var{width} or @var{height} is 0, the
5309 corresponding input size is used for the output.
5311 The @var{width} expression can reference the value set by the
5312 @var{height} expression, and vice versa.
5314 The default value of @var{width} and @var{height} is 0.
5318 Specify an expression for the offsets where to place the input image
5319 in the padded area with respect to the top/left border of the output
5322 The @var{x} expression can reference the value set by the @var{y}
5323 expression, and vice versa.
5325 The default value of @var{x} and @var{y} is 0.
5328 Specify the color of the padded area, it can be the name of a color
5329 (case insensitive match) or a 0xRRGGBB[AA] sequence.
5331 The default value of @var{color} is "black".
5334 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
5335 options are expressions containing the following constants:
5340 the input video width and height
5344 same as @var{in_w} and @var{in_h}
5348 the output width and height, that is the size of the padded area as
5349 specified by the @var{width} and @var{height} expressions
5353 same as @var{out_w} and @var{out_h}
5357 x and y offsets as specified by the @var{x} and @var{y}
5358 expressions, or NAN if not yet specified
5361 same as @var{iw} / @var{ih}
5364 input sample aspect ratio
5367 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
5371 horizontal and vertical chroma subsample values. For example for the
5372 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5375 @subsection Examples
5379 Add paddings with color "violet" to the input video. Output video
5380 size is 640x480, the top-left corner of the input video is placed at
5383 pad=640:480:0:40:violet
5386 The example above is equivalent to the following command:
5388 pad=width=640:height=480:x=0:y=40:color=violet
5392 Pad the input to get an output with dimensions increased by 3/2,
5393 and put the input video at the center of the padded area:
5395 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
5399 Pad the input to get a squared output with size equal to the maximum
5400 value between the input width and height, and put the input video at
5401 the center of the padded area:
5403 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
5407 Pad the input to get a final w/h ratio of 16:9:
5409 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
5413 In case of anamorphic video, in order to set the output display aspect
5414 correctly, it is necessary to use @var{sar} in the expression,
5415 according to the relation:
5417 (ih * X / ih) * sar = output_dar
5418 X = output_dar / sar
5421 Thus the previous example needs to be modified to:
5423 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
5427 Double output size and put the input video in the bottom-right
5428 corner of the output padded area:
5430 pad="2*iw:2*ih:ow-iw:oh-ih"
5434 @section pixdesctest
5436 Pixel format descriptor test filter, mainly useful for internal
5437 testing. The output video should be equal to the input video.
5441 format=monow, pixdesctest
5444 can be used to test the monowhite pixel format descriptor definition.
5448 Enable the specified chain of postprocessing subfilters using libpostproc. This
5449 library should be automatically selected with a GPL build (@code{--enable-gpl}).
5450 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
5451 Each subfilter and some options have a short and a long name that can be used
5452 interchangeably, i.e. dr/dering are the same.
5454 The filters accept the following options:
5458 Set postprocessing subfilters string.
5461 All subfilters share common options to determine their scope:
5465 Honor the quality commands for this subfilter.
5468 Do chrominance filtering, too (default).
5471 Do luminance filtering only (no chrominance).
5474 Do chrominance filtering only (no luminance).
5477 These options can be appended after the subfilter name, separated by a '|'.
5479 Available subfilters are:
5482 @item hb/hdeblock[|difference[|flatness]]
5483 Horizontal deblocking filter
5486 Difference factor where higher values mean more deblocking (default: @code{32}).
5488 Flatness threshold where lower values mean more deblocking (default: @code{39}).
5491 @item vb/vdeblock[|difference[|flatness]]
5492 Vertical deblocking filter
5495 Difference factor where higher values mean more deblocking (default: @code{32}).
5497 Flatness threshold where lower values mean more deblocking (default: @code{39}).
5500 @item ha/hadeblock[|difference[|flatness]]
5501 Accurate horizontal deblocking filter
5504 Difference factor where higher values mean more deblocking (default: @code{32}).
5506 Flatness threshold where lower values mean more deblocking (default: @code{39}).
5509 @item va/vadeblock[|difference[|flatness]]
5510 Accurate vertical deblocking filter
5513 Difference factor where higher values mean more deblocking (default: @code{32}).
5515 Flatness threshold where lower values mean more deblocking (default: @code{39}).
5519 The horizontal and vertical deblocking filters share the difference and
5520 flatness values so you cannot set different horizontal and vertical
5525 Experimental horizontal deblocking filter
5528 Experimental vertical deblocking filter
5533 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
5536 larger -> stronger filtering
5538 larger -> stronger filtering
5540 larger -> stronger filtering
5543 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
5546 Stretch luminance to @code{0-255}.
5549 @item lb/linblenddeint
5550 Linear blend deinterlacing filter that deinterlaces the given block by
5551 filtering all lines with a @code{(1 2 1)} filter.
5553 @item li/linipoldeint
5554 Linear interpolating deinterlacing filter that deinterlaces the given block by
5555 linearly interpolating every second line.
5557 @item ci/cubicipoldeint
5558 Cubic interpolating deinterlacing filter deinterlaces the given block by
5559 cubically interpolating every second line.
5561 @item md/mediandeint
5562 Median deinterlacing filter that deinterlaces the given block by applying a
5563 median filter to every second line.
5565 @item fd/ffmpegdeint
5566 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
5567 second line with a @code{(-1 4 2 4 -1)} filter.
5570 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
5571 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
5573 @item fq/forceQuant[|quantizer]
5574 Overrides the quantizer table from the input with the constant quantizer you
5582 Default pp filter combination (@code{hb|a,vb|a,dr|a})
5585 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
5588 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
5591 @subsection Examples
5595 Apply horizontal and vertical deblocking, deringing and automatic
5596 brightness/contrast:
5602 Apply default filters without brightness/contrast correction:
5608 Apply default filters and temporal denoiser:
5610 pp=default/tmpnoise|1|2|3
5614 Apply deblocking on luminance only, and switch vertical deblocking on or off
5615 automatically depending on available CPU time:
5623 Suppress a TV station logo, using an image file to determine which
5624 pixels comprise the logo. It works by filling in the pixels that
5625 comprise the logo with neighboring pixels.
5627 The filter accepts the following options:
5631 Set the filter bitmap file, which can be any image format supported by
5632 libavformat. The width and height of the image file must match those of the
5633 video stream being processed.
5636 Pixels in the provided bitmap image with a value of zero are not
5637 considered part of the logo, non-zero pixels are considered part of
5638 the logo. If you use white (255) for the logo and black (0) for the
5639 rest, you will be safe. For making the filter bitmap, it is
5640 recommended to take a screen capture of a black frame with the logo
5641 visible, and then using a threshold filter followed by the erode
5642 filter once or twice.
5644 If needed, little splotches can be fixed manually. Remember that if
5645 logo pixels are not covered, the filter quality will be much
5646 reduced. Marking too many pixels as part of the logo does not hurt as
5647 much, but it will increase the amount of blurring needed to cover over
5648 the image and will destroy more information than necessary, and extra
5649 pixels will slow things down on a large logo.
5653 Scale (resize) the input video, using the libswscale library.
5655 The scale filter forces the output display aspect ratio to be the same
5656 of the input, by changing the output sample aspect ratio.
5658 The filter accepts the following options:
5662 Set the output video width expression. Default value is @code{iw}. See
5663 below for the list of accepted constants.
5666 Set the output video height expression. Default value is @code{ih}.
5667 See below for the list of accepted constants.
5670 Set the interlacing. It accepts the following values:
5674 force interlaced aware scaling
5677 do not apply interlaced scaling
5680 select interlaced aware scaling depending on whether the source frames
5681 are flagged as interlaced or not
5684 Default value is @code{0}.
5687 Set libswscale scaling flags. If not explictly specified the filter
5688 applies a bilinear scaling algorithm.
5691 Set the video size, the value must be a valid abbreviation or in the
5692 form @var{width}x@var{height}.
5695 The values of the @var{w} and @var{h} options are expressions
5696 containing the following constants:
5701 the input width and height
5705 same as @var{in_w} and @var{in_h}
5709 the output (cropped) width and height
5713 same as @var{out_w} and @var{out_h}
5716 same as @var{iw} / @var{ih}
5719 input sample aspect ratio
5722 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
5726 horizontal and vertical chroma subsample values. For example for the
5727 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5730 If the input image format is different from the format requested by
5731 the next filter, the scale filter will convert the input to the
5734 If the value for @var{w} or @var{h} is 0, the respective input
5735 size is used for the output.
5737 If the value for @var{w} or @var{h} is -1, the scale filter will use, for the
5738 respective output size, a value that maintains the aspect ratio of the input
5741 @subsection Examples
5745 Scale the input video to a size of 200x100:
5750 This is equivalent to:
5761 Specify a size abbreviation for the output size:
5766 which can also be written as:
5772 Scale the input to 2x:
5778 The above is the same as:
5784 Scale the input to 2x with forced interlaced scaling:
5786 scale=2*iw:2*ih:interl=1
5790 Scale the input to half size:
5796 Increase the width, and set the height to the same size:
5802 Seek for Greek harmony:
5809 Increase the height, and set the width to 3/2 of the height:
5811 scale=w=3/2*oh:h=3/5*ih
5815 Increase the size, but make the size a multiple of the chroma
5818 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
5822 Increase the width to a maximum of 500 pixels, keep the same input
5825 scale=w='min(500\, iw*3/2):h=-1'
5829 @section separatefields
5831 The @code{separatefields} takes a frame-based video input and splits
5832 each frame into its components fields, producing a new half height clip
5833 with twice the frame rate and twice the frame count.
5835 This filter use field-dominance information in frame to decide which
5836 of each pair of fields to place first in the output.
5837 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
5839 @section setdar, setsar
5841 The @code{setdar} filter sets the Display Aspect Ratio for the filter
5844 This is done by changing the specified Sample (aka Pixel) Aspect
5845 Ratio, according to the following equation:
5847 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
5850 Keep in mind that the @code{setdar} filter does not modify the pixel
5851 dimensions of the video frame. Also the display aspect ratio set by
5852 this filter may be changed by later filters in the filterchain,
5853 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
5856 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
5857 the filter output video.
5859 Note that as a consequence of the application of this filter, the
5860 output display aspect ratio will change according to the equation
5863 Keep in mind that the sample aspect ratio set by the @code{setsar}
5864 filter may be changed by later filters in the filterchain, e.g. if
5865 another "setsar" or a "setdar" filter is applied.
5867 The filters accept the following options:
5870 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
5871 Set the aspect ratio used by the filter.
5873 The parameter can be a floating point number string, an expression, or
5874 a string of the form @var{num}:@var{den}, where @var{num} and
5875 @var{den} are the numerator and denominator of the aspect ratio. If
5876 the parameter is not specified, it is assumed the value "0".
5877 In case the form "@var{num}:@var{den}" is used, the @code{:} character
5881 Set the maximum integer value to use for expressing numerator and
5882 denominator when reducing the expressed aspect ratio to a rational.
5883 Default value is @code{100}.
5887 @subsection Examples
5892 To change the display aspect ratio to 16:9, specify one of the following:
5900 To change the sample aspect ratio to 10:11, specify:
5906 To set a display aspect ratio of 16:9, and specify a maximum integer value of
5907 1000 in the aspect ratio reduction, use the command:
5909 setdar=ratio=16/9:max=1000
5917 Force field for the output video frame.
5919 The @code{setfield} filter marks the interlace type field for the
5920 output frames. It does not change the input frame, but only sets the
5921 corresponding property, which affects how the frame is treated by
5922 following filters (e.g. @code{fieldorder} or @code{yadif}).
5924 The filter accepts the following options:
5929 Available values are:
5933 Keep the same field property.
5936 Mark the frame as bottom-field-first.
5939 Mark the frame as top-field-first.
5942 Mark the frame as progressive.
5948 Show a line containing various information for each input video frame.
5949 The input video is not modified.
5951 The shown line contains a sequence of key/value pairs of the form
5952 @var{key}:@var{value}.
5954 A description of each shown parameter follows:
5958 sequential number of the input frame, starting from 0
5961 Presentation TimeStamp of the input frame, expressed as a number of
5962 time base units. The time base unit depends on the filter input pad.
5965 Presentation TimeStamp of the input frame, expressed as a number of
5969 position of the frame in the input stream, -1 if this information in
5970 unavailable and/or meaningless (for example in case of synthetic video)
5976 sample aspect ratio of the input frame, expressed in the form
5980 size of the input frame, expressed in the form
5981 @var{width}x@var{height}
5984 interlaced mode ("P" for "progressive", "T" for top field first, "B"
5985 for bottom field first)
5988 1 if the frame is a key frame, 0 otherwise
5991 picture type of the input frame ("I" for an I-frame, "P" for a
5992 P-frame, "B" for a B-frame, "?" for unknown type).
5993 Check also the documentation of the @code{AVPictureType} enum and of
5994 the @code{av_get_picture_type_char} function defined in
5995 @file{libavutil/avutil.h}.
5998 Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame
6000 @item plane_checksum
6001 Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
6002 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]"
6008 Blur the input video without impacting the outlines.
6010 The filter accepts the following options:
6013 @item luma_radius, lr
6014 Set the luma radius. The option value must be a float number in
6015 the range [0.1,5.0] that specifies the variance of the gaussian filter
6016 used to blur the image (slower if larger). Default value is 1.0.
6018 @item luma_strength, ls
6019 Set the luma strength. The option value must be a float number
6020 in the range [-1.0,1.0] that configures the blurring. A value included
6021 in [0.0,1.0] will blur the image whereas a value included in
6022 [-1.0,0.0] will sharpen the image. Default value is 1.0.
6024 @item luma_threshold, lt
6025 Set the luma threshold used as a coefficient to determine
6026 whether a pixel should be blurred or not. The option value must be an
6027 integer in the range [-30,30]. A value of 0 will filter all the image,
6028 a value included in [0,30] will filter flat areas and a value included
6029 in [-30,0] will filter edges. Default value is 0.
6031 @item chroma_radius, cr
6032 Set the chroma radius. The option value must be a float number in
6033 the range [0.1,5.0] that specifies the variance of the gaussian filter
6034 used to blur the image (slower if larger). Default value is 1.0.
6036 @item chroma_strength, cs
6037 Set the chroma strength. The option value must be a float number
6038 in the range [-1.0,1.0] that configures the blurring. A value included
6039 in [0.0,1.0] will blur the image whereas a value included in
6040 [-1.0,0.0] will sharpen the image. Default value is 1.0.
6042 @item chroma_threshold, ct
6043 Set the chroma threshold used as a coefficient to determine
6044 whether a pixel should be blurred or not. The option value must be an
6045 integer in the range [-30,30]. A value of 0 will filter all the image,
6046 a value included in [0,30] will filter flat areas and a value included
6047 in [-30,0] will filter edges. Default value is 0.
6050 If a chroma option is not explicitly set, the corresponding luma value
6055 Convert between different stereoscopic image formats.
6057 The filters accept the following options:
6061 Set stereoscopic image format of input.
6063 Available values for input image formats are:
6066 side by side parallel (left eye left, right eye right)
6069 side by side crosseye (right eye left, left eye right)
6072 side by side parallel with half width resolution
6073 (left eye left, right eye right)
6076 side by side crosseye with half width resolution
6077 (right eye left, left eye right)
6080 above-below (left eye above, right eye below)
6083 above-below (right eye above, left eye below)
6086 above-below with half height resolution
6087 (left eye above, right eye below)
6090 above-below with half height resolution
6091 (right eye above, left eye below)
6094 alternating frames (left eye first, right eye second)
6097 alternating frames (right eye first, left eye second)
6099 Default value is @samp{sbsl}.
6103 Set stereoscopic image format of output.
6105 Available values for output image formats are all the input formats as well as:
6108 anaglyph red/blue gray
6109 (red filter on left eye, blue filter on right eye)
6112 anaglyph red/green gray
6113 (red filter on left eye, green filter on right eye)
6116 anaglyph red/cyan gray
6117 (red filter on left eye, cyan filter on right eye)
6120 anaglyph red/cyan half colored
6121 (red filter on left eye, cyan filter on right eye)
6124 anaglyph red/cyan color
6125 (red filter on left eye, cyan filter on right eye)
6128 anaglyph red/cyan color optimized with the least squares projection of dubois
6129 (red filter on left eye, cyan filter on right eye)
6132 anaglyph green/magenta gray
6133 (green filter on left eye, magenta filter on right eye)
6136 anaglyph green/magenta half colored
6137 (green filter on left eye, magenta filter on right eye)
6140 anaglyph green/magenta colored
6141 (green filter on left eye, magenta filter on right eye)
6144 anaglyph green/magenta color optimized with the least squares projection of dubois
6145 (green filter on left eye, magenta filter on right eye)
6148 anaglyph yellow/blue gray
6149 (yellow filter on left eye, blue filter on right eye)
6152 anaglyph yellow/blue half colored
6153 (yellow filter on left eye, blue filter on right eye)
6156 anaglyph yellow/blue colored
6157 (yellow filter on left eye, blue filter on right eye)
6160 anaglyph yellow/blue color optimized with the least squares projection of dubois
6161 (yellow filter on left eye, blue filter on right eye)
6164 interleaved rows (left eye has top row, right eye starts on next row)
6167 interleaved rows (right eye has top row, left eye starts on next row)
6170 mono output (left eye only)
6173 mono output (right eye only)
6176 Default value is @samp{arcd}.
6179 @subsection Examples
6183 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
6189 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
6198 Draw subtitles on top of input video using the libass library.
6200 To enable compilation of this filter you need to configure FFmpeg with
6201 @code{--enable-libass}. This filter also requires a build with libavcodec and
6202 libavformat to convert the passed subtitles file to ASS (Advanced Substation
6203 Alpha) subtitles format.
6205 The filter accepts the following options:
6209 Set the filename of the subtitle file to read. It must be specified.
6212 Specify the size of the original video, the video for which the ASS file
6213 was composed. Due to a misdesign in ASS aspect ratio arithmetic, this is
6214 necessary to correctly scale the fonts if the aspect ratio has been changed.
6217 Set subtitles input character encoding. @code{subtitles} filter only. Only
6218 useful if not UTF-8.
6221 If the first key is not specified, it is assumed that the first value
6222 specifies the @option{filename}.
6224 For example, to render the file @file{sub.srt} on top of the input
6225 video, use the command:
6230 which is equivalent to:
6232 subtitles=filename=sub.srt
6237 Scale the input by 2x and smooth using the Super2xSaI (Scale and
6238 Interpolate) pixel art scaling algorithm.
6240 Useful for enlarging pixel art images without reducing sharpness.
6247 Apply telecine process to the video.
6249 This filter accepts the following options:
6258 The default value is @code{top}.
6262 A string of numbers representing the pulldown pattern you wish to apply.
6263 The default value is @code{23}.
6267 Some typical patterns:
6272 24p: 2332 (preferred)
6279 24p: 222222222223 ("Euro pulldown")
6285 Select the most representative frame in a given sequence of consecutive frames.
6287 The filter accepts the following options:
6291 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
6292 will pick one of them, and then handle the next batch of @var{n} frames until
6293 the end. Default is @code{100}.
6296 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
6297 value will result in a higher memory usage, so a high value is not recommended.
6299 @subsection Examples
6303 Extract one picture each 50 frames:
6309 Complete example of a thumbnail creation with @command{ffmpeg}:
6311 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
6317 Tile several successive frames together.
6319 The filter accepts the following options:
6324 Set the grid size (i.e. the number of lines and columns) in the form
6328 Set the maximum number of frames to render in the given area. It must be less
6329 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
6330 the area will be used.
6333 Set the outer border margin in pixels.
6336 Set the inner border thickness (i.e. the number of pixels between frames). For
6337 more advanced padding options (such as having different values for the edges),
6338 refer to the pad video filter.
6342 @subsection Examples
6346 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
6348 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
6350 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
6351 duplicating each output frame to accomodate the originally detected frame
6355 Display @code{5} pictures in an area of @code{3x2} frames,
6356 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
6357 mixed flat and named options:
6359 tile=3x2:nb_frames=5:padding=7:margin=2
6365 Perform various types of temporal field interlacing.
6367 Frames are counted starting from 1, so the first input frame is
6370 The filter accepts the following options:
6375 Specify the mode of the interlacing. This option can also be specified
6376 as a value alone. See below for a list of values for this option.
6378 Available values are:
6382 Move odd frames into the upper field, even into the lower field,
6383 generating a double height frame at half frame rate.
6386 Only output even frames, odd frames are dropped, generating a frame with
6387 unchanged height at half frame rate.
6390 Only output odd frames, even frames are dropped, generating a frame with
6391 unchanged height at half frame rate.
6394 Expand each frame to full height, but pad alternate lines with black,
6395 generating a frame with double height at the same input frame rate.
6397 @item interleave_top, 4
6398 Interleave the upper field from odd frames with the lower field from
6399 even frames, generating a frame with unchanged height at half frame rate.
6401 @item interleave_bottom, 5
6402 Interleave the lower field from odd frames with the upper field from
6403 even frames, generating a frame with unchanged height at half frame rate.
6405 @item interlacex2, 6
6406 Double frame rate with unchanged height. Frames are inserted each
6407 containing the second temporal field from the previous input frame and
6408 the first temporal field from the next input frame. This mode relies on
6409 the top_field_first flag. Useful for interlaced video displays with no
6410 field synchronisation.
6413 Numeric values are deprecated but are accepted for backward
6414 compatibility reasons.
6416 Default mode is @code{merge}.
6419 Specify flags influencing the filter process.
6421 Available value for @var{flags} is:
6424 @item low_pass_filter, vlfp
6425 Enable vertical low-pass filtering in the filter.
6426 Vertical low-pass filtering is required when creating an interlaced
6427 destination from a progressive source which contains high-frequency
6428 vertical detail. Filtering will reduce interlace 'twitter' and Moire
6431 Vertical low-pass filtering can only be enabled for @option{mode}
6432 @var{interleave_top} and @var{interleave_bottom}.
6439 Transpose rows with columns in the input video and optionally flip it.
6441 This filter accepts the following options:
6446 Specify the transposition direction.
6448 Can assume the following values:
6450 @item 0, 4, cclock_flip
6451 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
6459 Rotate by 90 degrees clockwise, that is:
6467 Rotate by 90 degrees counterclockwise, that is:
6474 @item 3, 7, clock_flip
6475 Rotate by 90 degrees clockwise and vertically flip, that is:
6483 For values between 4-7, the transposition is only done if the input
6484 video geometry is portrait and not landscape. These values are
6485 deprecated, the @code{passthrough} option should be used instead.
6487 Numerical values are deprecated, and should be dropped in favor of
6491 Do not apply the transposition if the input geometry matches the one
6492 specified by the specified value. It accepts the following values:
6495 Always apply transposition.
6497 Preserve portrait geometry (when @var{height} >= @var{width}).
6499 Preserve landscape geometry (when @var{width} >= @var{height}).
6502 Default value is @code{none}.
6505 For example to rotate by 90 degrees clockwise and preserve portrait
6508 transpose=dir=1:passthrough=portrait
6511 The command above can also be specified as:
6513 transpose=1:portrait
6517 Trim the input so that the output contains one continuous subpart of the input.
6519 This filter accepts the following options:
6522 Timestamp (in seconds) of the start of the kept section. I.e. the frame with the
6523 timestamp @var{start} will be the first frame in the output.
6526 Timestamp (in seconds) of the first frame that will be dropped. I.e. the frame
6527 immediately preceding the one with the timestamp @var{end} will be the last
6528 frame in the output.
6531 Same as @var{start}, except this option sets the start timestamp in timebase
6532 units instead of seconds.
6535 Same as @var{end}, except this option sets the end timestamp in timebase units
6539 Maximum duration of the output in seconds.
6542 Number of the first frame that should be passed to output.
6545 Number of the first frame that should be dropped.
6548 Note that the first two sets of the start/end options and the @option{duration}
6549 option look at the frame timestamp, while the _frame variants simply count the
6550 frames that pass through the filter. Also note that this filter does not modify
6551 the timestamps. If you wish that the output timestamps start at zero, insert a
6552 setpts filter after the trim filter.
6554 If multiple start or end options are set, this filter tries to be greedy and
6555 keep all the frames that match at least one of the specified constraints. To keep
6556 only the part that matches all the constraints at once, chain multiple trim
6559 The defaults are such that all the input is kept. So it is possible to set e.g.
6560 just the end values to keep everything before the specified time.
6565 drop everything except the second minute of input
6567 ffmpeg -i INPUT -vf trim=60:120
6571 keep only the first second
6573 ffmpeg -i INPUT -vf trim=duration=1
6581 Sharpen or blur the input video.
6583 It accepts the following parameters:
6586 @item luma_msize_x, lx
6587 Set the luma matrix horizontal size. It must be an odd integer between
6588 3 and 63, default value is 5.
6590 @item luma_msize_y, ly
6591 Set the luma matrix vertical size. It must be an odd integer between 3
6592 and 63, default value is 5.
6594 @item luma_amount, la
6595 Set the luma effect strength. It can be a float number, reasonable
6596 values lay between -1.5 and 1.5.
6598 Negative values will blur the input video, while positive values will
6599 sharpen it, a value of zero will disable the effect.
6601 Default value is 1.0.
6603 @item chroma_msize_x, cx
6604 Set the chroma matrix horizontal size. It must be an odd integer
6605 between 3 and 63, default value is 5.
6607 @item chroma_msize_y, cy
6608 Set the chroma matrix vertical size. It must be an odd integer
6609 between 3 and 63, default value is 5.
6611 @item chroma_amount, ca
6612 Set the chroma effect strength. It can be a float number, reasonable
6613 values lay between -1.5 and 1.5.
6615 Negative values will blur the input video, while positive values will
6616 sharpen it, a value of zero will disable the effect.
6618 Default value is 0.0.
6621 If set to 1, specify using OpenCL capabilities, only available if
6622 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
6626 All parameters are optional and default to the equivalent of the
6627 string '5:5:1.0:5:5:0.0'.
6629 @subsection Examples
6633 Apply strong luma sharpen effect:
6635 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
6639 Apply strong blur of both luma and chroma parameters:
6641 unsharp=7:7:-2:7:7:-2
6645 @anchor{vidstabdetect}
6646 @section vidstabdetect
6648 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
6649 @ref{vidstabtransform} for pass 2.
6651 This filter generates a file with relative translation and rotation
6652 transform information about subsequent frames, which is then used by
6653 the @ref{vidstabtransform} filter.
6655 To enable compilation of this filter you need to configure FFmpeg with
6656 @code{--enable-libvidstab}.
6658 This filter accepts the following options:
6662 Set the path to the file used to write the transforms information.
6663 Default value is @file{transforms.trf}.
6666 Set how shaky the video is and how quick the camera is. It accepts an
6667 integer in the range 1-10, a value of 1 means little shakiness, a
6668 value of 10 means strong shakiness. Default value is 5.
6671 Set the accuracy of the detection process. It must be a value in the
6672 range 1-15. A value of 1 means low accuracy, a value of 15 means high
6673 accuracy. Default value is 9.
6676 Set stepsize of the search process. The region around minimum is
6677 scanned with 1 pixel resolution. Default value is 6.
6680 Set minimum contrast. Below this value a local measurement field is
6681 discarded. Must be a floating point value in the range 0-1. Default
6685 Set reference frame number for tripod mode.
6687 If enabled, the motion of the frames is compared to a reference frame
6688 in the filtered stream, identified by the specified number. The idea
6689 is to compensate all movements in a more-or-less static scene and keep
6690 the camera view absolutely still.
6692 If set to 0, it is disabled. The frames are counted starting from 1.
6695 Show fields and transforms in the resulting frames. It accepts an
6696 integer in the range 0-2. Default value is 0, which disables any
6700 @subsection Examples
6710 Analyze strongly shaky movie and put the results in file
6711 @file{mytransforms.trf}:
6713 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
6717 Visualize the result of internal transformations in the resulting
6720 vidstabdetect=show=1
6724 Analyze a video with medium shakiness using @command{ffmpeg}:
6726 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
6730 @anchor{vidstabtransform}
6731 @section vidstabtransform
6733 Video stabilization/deshaking: pass 2 of 2,
6734 see @ref{vidstabdetect} for pass 1.
6736 Read a file with transform information for each frame and
6737 apply/compensate them. Together with the @ref{vidstabdetect}
6738 filter this can be used to deshake videos. See also
6739 @url{http://public.hronopik.de/vid.stab}. It is important to also use
6740 the unsharp filter, see below.
6742 To enable compilation of this filter you need to configure FFmpeg with
6743 @code{--enable-libvidstab}.
6745 This filter accepts the following options:
6750 path to the file used to read the transforms (default: @file{transforms.trf})
6753 number of frames (value*2 + 1) used for lowpass filtering the camera movements
6754 (default: 10). For example a number of 10 means that 21 frames are used
6755 (10 in the past and 10 in the future) to smoothen the motion in the
6756 video. A larger values leads to a smoother video, but limits the
6757 acceleration of the camera (pan/tilt movements).
6760 maximal number of pixels to translate frames (default: -1 no limit)
6763 maximal angle in radians (degree*PI/180) to rotate frames (default: -1
6767 How to deal with borders that may be visible due to movement
6768 compensation. Available values are:
6772 keep image information from previous frame (default)
6774 fill the border black
6780 keep transforms normal (default)
6787 consider transforms as
6792 relative to previous frame (default)
6797 percentage to zoom (default: 0)
6806 if 1 then optimal zoom value is determined (default).
6807 Optimal zoom means no (or only little) border should be visible.
6808 Note that the value given at zoom is added to the one calculated
6812 type of interpolation
6814 Available values are:
6819 linear only horizontal
6821 linear in both directions (default)
6823 cubic in both directions (slow)
6827 virtual tripod mode means that the video is stabilized such that the
6828 camera stays stationary. Use also @code{tripod} option of
6829 @ref{vidstabdetect}.
6834 virtual tripod mode: equivalent to @code{relative=0:smoothing=0}
6839 @subsection Examples
6843 typical call with default default values:
6844 (note the unsharp filter which is always recommended)
6846 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
6850 zoom in a bit more and load transform data from a given file
6852 vidstabtransform=zoom=5:input="mytransforms.trf"
6856 smoothen the video even more
6858 vidstabtransform=smoothing=30
6865 Flip the input video vertically.
6867 For example, to vertically flip a video with @command{ffmpeg}:
6869 ffmpeg -i in.avi -vf "vflip" out.avi
6875 Deinterlace the input video ("yadif" means "yet another deinterlacing
6878 This filter accepts the following options:
6884 The interlacing mode to adopt, accepts one of the following values:
6888 output 1 frame for each frame
6890 output 1 frame for each field
6891 @item 2, send_frame_nospatial
6892 like @code{send_frame} but skip spatial interlacing check
6893 @item 3, send_field_nospatial
6894 like @code{send_field} but skip spatial interlacing check
6897 Default value is @code{send_frame}.
6900 The picture field parity assumed for the input interlaced video, accepts one of
6901 the following values:
6905 assume top field first
6907 assume bottom field first
6909 enable automatic detection
6912 Default value is @code{auto}.
6913 If interlacing is unknown or decoder does not export this information,
6914 top field first will be assumed.
6917 Specify which frames to deinterlace. Accept one of the following
6922 deinterlace all frames
6924 only deinterlace frames marked as interlaced
6927 Default value is @code{all}.
6930 @c man end VIDEO FILTERS
6932 @chapter Video Sources
6933 @c man begin VIDEO SOURCES
6935 Below is a description of the currently available video sources.
6939 Buffer video frames, and make them available to the filter chain.
6941 This source is mainly intended for a programmatic use, in particular
6942 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
6944 This source accepts the following options:
6949 Specify the size (width and height) of the buffered video frames.
6958 A string representing the pixel format of the buffered video frames.
6959 It may be a number corresponding to a pixel format, or a pixel format
6963 Specify the timebase assumed by the timestamps of the buffered frames.
6966 Specify the frame rate expected for the video stream.
6968 @item pixel_aspect, sar
6969 Specify the sample aspect ratio assumed by the video frames.
6972 Specify the optional parameters to be used for the scale filter which
6973 is automatically inserted when an input change is detected in the
6974 input size or format.
6979 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
6982 will instruct the source to accept video frames with size 320x240 and
6983 with format "yuv410p", assuming 1/24 as the timestamps timebase and
6984 square pixels (1:1 sample aspect ratio).
6985 Since the pixel format with name "yuv410p" corresponds to the number 6
6986 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
6987 this example corresponds to:
6989 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
6992 Alternatively, the options can be specified as a flat string, but this
6993 syntax is deprecated:
6995 @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}]
6999 Create a pattern generated by an elementary cellular automaton.
7001 The initial state of the cellular automaton can be defined through the
7002 @option{filename}, and @option{pattern} options. If such options are
7003 not specified an initial state is created randomly.
7005 At each new frame a new row in the video is filled with the result of
7006 the cellular automaton next generation. The behavior when the whole
7007 frame is filled is defined by the @option{scroll} option.
7009 This source accepts the following options:
7013 Read the initial cellular automaton state, i.e. the starting row, from
7015 In the file, each non-whitespace character is considered an alive
7016 cell, a newline will terminate the row, and further characters in the
7017 file will be ignored.
7020 Read the initial cellular automaton state, i.e. the starting row, from
7021 the specified string.
7023 Each non-whitespace character in the string is considered an alive
7024 cell, a newline will terminate the row, and further characters in the
7025 string will be ignored.
7028 Set the video rate, that is the number of frames generated per second.
7031 @item random_fill_ratio, ratio
7032 Set the random fill ratio for the initial cellular automaton row. It
7033 is a floating point number value ranging from 0 to 1, defaults to
7036 This option is ignored when a file or a pattern is specified.
7038 @item random_seed, seed
7039 Set the seed for filling randomly the initial row, must be an integer
7040 included between 0 and UINT32_MAX. If not specified, or if explicitly
7041 set to -1, the filter will try to use a good random seed on a best
7045 Set the cellular automaton rule, it is a number ranging from 0 to 255.
7046 Default value is 110.
7049 Set the size of the output video.
7051 If @option{filename} or @option{pattern} is specified, the size is set
7052 by default to the width of the specified initial state row, and the
7053 height is set to @var{width} * PHI.
7055 If @option{size} is set, it must contain the width of the specified
7056 pattern string, and the specified pattern will be centered in the
7059 If a filename or a pattern string is not specified, the size value
7060 defaults to "320x518" (used for a randomly generated initial state).
7063 If set to 1, scroll the output upward when all the rows in the output
7064 have been already filled. If set to 0, the new generated row will be
7065 written over the top row just after the bottom row is filled.
7068 @item start_full, full
7069 If set to 1, completely fill the output with generated rows before
7070 outputting the first frame.
7071 This is the default behavior, for disabling set the value to 0.
7074 If set to 1, stitch the left and right row edges together.
7075 This is the default behavior, for disabling set the value to 0.
7078 @subsection Examples
7082 Read the initial state from @file{pattern}, and specify an output of
7085 cellauto=f=pattern:s=200x400
7089 Generate a random initial row with a width of 200 cells, with a fill
7092 cellauto=ratio=2/3:s=200x200
7096 Create a pattern generated by rule 18 starting by a single alive cell
7097 centered on an initial row with width 100:
7099 cellauto=p=@@:s=100x400:full=0:rule=18
7103 Specify a more elaborated initial pattern:
7105 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
7112 Generate a Mandelbrot set fractal, and progressively zoom towards the
7113 point specified with @var{start_x} and @var{start_y}.
7115 This source accepts the following options:
7120 Set the terminal pts value. Default value is 400.
7123 Set the terminal scale value.
7124 Must be a floating point value. Default value is 0.3.
7127 Set the inner coloring mode, that is the algorithm used to draw the
7128 Mandelbrot fractal internal region.
7130 It shall assume one of the following values:
7135 Show time until convergence.
7137 Set color based on point closest to the origin of the iterations.
7142 Default value is @var{mincol}.
7145 Set the bailout value. Default value is 10.0.
7148 Set the maximum of iterations performed by the rendering
7149 algorithm. Default value is 7189.
7152 Set outer coloring mode.
7153 It shall assume one of following values:
7155 @item iteration_count
7156 Set iteration cound mode.
7157 @item normalized_iteration_count
7158 set normalized iteration count mode.
7160 Default value is @var{normalized_iteration_count}.
7163 Set frame rate, expressed as number of frames per second. Default
7167 Set frame size. Default value is "640x480".
7170 Set the initial scale value. Default value is 3.0.
7173 Set the initial x position. Must be a floating point value between
7174 -100 and 100. Default value is -0.743643887037158704752191506114774.
7177 Set the initial y position. Must be a floating point value between
7178 -100 and 100. Default value is -0.131825904205311970493132056385139.
7183 Generate various test patterns, as generated by the MPlayer test filter.
7185 The size of the generated video is fixed, and is 256x256.
7186 This source is useful in particular for testing encoding features.
7188 This source accepts the following options:
7193 Specify the frame rate of the sourced video, as the number of frames
7194 generated per second. It has to be a string in the format
7195 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
7196 number or a valid video frame rate abbreviation. The default value is
7200 Set the video duration of the sourced video. The accepted syntax is:
7205 See also the function @code{av_parse_time()}.
7207 If not specified, or the expressed duration is negative, the video is
7208 supposed to be generated forever.
7212 Set the number or the name of the test to perform. Supported tests are:
7227 Default value is "all", which will cycle through the list of all tests.
7230 For example the following:
7235 will generate a "dc_luma" test pattern.
7239 Provide a frei0r source.
7241 To enable compilation of this filter you need to install the frei0r
7242 header and configure FFmpeg with @code{--enable-frei0r}.
7244 This source accepts the following options:
7249 The size of the video to generate, may be a string of the form
7250 @var{width}x@var{height} or a frame size abbreviation.
7253 Framerate of the generated video, may be a string of the form
7254 @var{num}/@var{den} or a frame rate abbreviation.
7257 The name to the frei0r source to load. For more information regarding frei0r and
7258 how to set the parameters read the section @ref{frei0r} in the description of
7262 A '|'-separated list of parameters to pass to the frei0r source.
7266 For example, to generate a frei0r partik0l source with size 200x200
7267 and frame rate 10 which is overlayed on the overlay filter main input:
7269 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
7274 Generate a life pattern.
7276 This source is based on a generalization of John Conway's life game.
7278 The sourced input represents a life grid, each pixel represents a cell
7279 which can be in one of two possible states, alive or dead. Every cell
7280 interacts with its eight neighbours, which are the cells that are
7281 horizontally, vertically, or diagonally adjacent.
7283 At each interaction the grid evolves according to the adopted rule,
7284 which specifies the number of neighbor alive cells which will make a
7285 cell stay alive or born. The @option{rule} option allows to specify
7288 This source accepts the following options:
7292 Set the file from which to read the initial grid state. In the file,
7293 each non-whitespace character is considered an alive cell, and newline
7294 is used to delimit the end of each row.
7296 If this option is not specified, the initial grid is generated
7300 Set the video rate, that is the number of frames generated per second.
7303 @item random_fill_ratio, ratio
7304 Set the random fill ratio for the initial random grid. It is a
7305 floating point number value ranging from 0 to 1, defaults to 1/PHI.
7306 It is ignored when a file is specified.
7308 @item random_seed, seed
7309 Set the seed for filling the initial random grid, must be an integer
7310 included between 0 and UINT32_MAX. If not specified, or if explicitly
7311 set to -1, the filter will try to use a good random seed on a best
7317 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
7318 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
7319 @var{NS} specifies the number of alive neighbor cells which make a
7320 live cell stay alive, and @var{NB} the number of alive neighbor cells
7321 which make a dead cell to become alive (i.e. to "born").
7322 "s" and "b" can be used in place of "S" and "B", respectively.
7324 Alternatively a rule can be specified by an 18-bits integer. The 9
7325 high order bits are used to encode the next cell state if it is alive
7326 for each number of neighbor alive cells, the low order bits specify
7327 the rule for "borning" new cells. Higher order bits encode for an
7328 higher number of neighbor cells.
7329 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
7330 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
7332 Default value is "S23/B3", which is the original Conway's game of life
7333 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
7334 cells, and will born a new cell if there are three alive cells around
7338 Set the size of the output video.
7340 If @option{filename} is specified, the size is set by default to the
7341 same size of the input file. If @option{size} is set, it must contain
7342 the size specified in the input file, and the initial grid defined in
7343 that file is centered in the larger resulting area.
7345 If a filename is not specified, the size value defaults to "320x240"
7346 (used for a randomly generated initial grid).
7349 If set to 1, stitch the left and right grid edges together, and the
7350 top and bottom edges also. Defaults to 1.
7353 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
7354 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
7355 value from 0 to 255.
7358 Set the color of living (or new born) cells.
7361 Set the color of dead cells. If @option{mold} is set, this is the first color
7362 used to represent a dead cell.
7365 Set mold color, for definitely dead and moldy cells.
7368 @subsection Examples
7372 Read a grid from @file{pattern}, and center it on a grid of size
7375 life=f=pattern:s=300x300
7379 Generate a random grid of size 200x200, with a fill ratio of 2/3:
7381 life=ratio=2/3:s=200x200
7385 Specify a custom rule for evolving a randomly generated grid:
7391 Full example with slow death effect (mold) using @command{ffplay}:
7393 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
7397 @section color, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
7399 The @code{color} source provides an uniformly colored input.
7401 The @code{nullsrc} source returns unprocessed video frames. It is
7402 mainly useful to be employed in analysis / debugging tools, or as the
7403 source for filters which ignore the input data.
7405 The @code{rgbtestsrc} source generates an RGB test pattern useful for
7406 detecting RGB vs BGR issues. You should see a red, green and blue
7407 stripe from top to bottom.
7409 The @code{smptebars} source generates a color bars pattern, based on
7410 the SMPTE Engineering Guideline EG 1-1990.
7412 The @code{smptehdbars} source generates a color bars pattern, based on
7413 the SMPTE RP 219-2002.
7415 The @code{testsrc} source generates a test video pattern, showing a
7416 color pattern, a scrolling gradient and a timestamp. This is mainly
7417 intended for testing purposes.
7419 The sources accept the following options:
7424 Specify the color of the source, only used in the @code{color}
7425 source. It can be the name of a color (case insensitive match) or a
7426 0xRRGGBB[AA] sequence, possibly followed by an alpha specifier. The
7427 default value is "black".
7430 Specify the size of the sourced video, it may be a string of the form
7431 @var{width}x@var{height}, or the name of a size abbreviation. The
7432 default value is "320x240".
7435 Specify the frame rate of the sourced video, as the number of frames
7436 generated per second. It has to be a string in the format
7437 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
7438 number or a valid video frame rate abbreviation. The default value is
7442 Set the sample aspect ratio of the sourced video.
7445 Set the video duration of the sourced video. The accepted syntax is:
7447 [-]HH[:MM[:SS[.m...]]]
7450 See also the function @code{av_parse_time()}.
7452 If not specified, or the expressed duration is negative, the video is
7453 supposed to be generated forever.
7456 Set the number of decimals to show in the timestamp, only available in the
7457 @code{testsrc} source.
7459 The displayed timestamp value will correspond to the original
7460 timestamp value multiplied by the power of 10 of the specified
7461 value. Default value is 0.
7464 For example the following:
7466 testsrc=duration=5.3:size=qcif:rate=10
7469 will generate a video with a duration of 5.3 seconds, with size
7470 176x144 and a frame rate of 10 frames per second.
7472 The following graph description will generate a red source
7473 with an opacity of 0.2, with size "qcif" and a frame rate of 10
7476 color=c=red@@0.2:s=qcif:r=10
7479 If the input content is to be ignored, @code{nullsrc} can be used. The
7480 following command generates noise in the luminance plane by employing
7481 the @code{geq} filter:
7483 nullsrc=s=256x256, geq=random(1)*255:128:128
7486 @subsection Commands
7488 The @code{color} source supports the following commands:
7492 Set the color of the created image. Accepts the same syntax of the
7493 corresponding @option{color} option.
7496 @c man end VIDEO SOURCES
7498 @chapter Video Sinks
7499 @c man begin VIDEO SINKS
7501 Below is a description of the currently available video sinks.
7505 Buffer video frames, and make them available to the end of the filter
7508 This sink is mainly intended for a programmatic use, in particular
7509 through the interface defined in @file{libavfilter/buffersink.h}
7510 or the options system.
7512 It accepts a pointer to an AVBufferSinkContext structure, which
7513 defines the incoming buffers' formats, to be passed as the opaque
7514 parameter to @code{avfilter_init_filter} for initialization.
7518 Null video sink, do absolutely nothing with the input video. It is
7519 mainly useful as a template and to be employed in analysis / debugging
7522 @c man end VIDEO SINKS
7524 @chapter Multimedia Filters
7525 @c man begin MULTIMEDIA FILTERS
7527 Below is a description of the currently available multimedia filters.
7529 @section avectorscope
7531 Convert input audio to a video output, representing the audio vector
7534 The filter is used to measure the difference between channels of stereo
7535 audio stream. A monoaural signal, consisting of identical left and right
7536 signal, results in straight vertical line. Any stereo separation is visible
7537 as a deviation from this line, creating a Lissajous figure.
7538 If the straight (or deviation from it) but horizontal line appears this
7539 indicates that the left and right channels are out of phase.
7541 The filter accepts the following options:
7545 Set the vectorscope mode.
7547 Available values are:
7550 Lissajous rotated by 45 degrees.
7553 Same as above but not rotated.
7556 Default value is @samp{lissajous}.
7559 Set the video size for the output. Default value is @code{400x400}.
7562 Set the output frame rate. Default value is @code{25}.
7567 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
7568 Allowed range is @code{[0, 255]}.
7573 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
7574 Allowed range is @code{[0, 255]}.
7577 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
7580 @subsection Examples
7584 Complete example using @command{ffplay}:
7586 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
7587 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
7593 Concatenate audio and video streams, joining them together one after the
7596 The filter works on segments of synchronized video and audio streams. All
7597 segments must have the same number of streams of each type, and that will
7598 also be the number of streams at output.
7600 The filter accepts the following options:
7605 Set the number of segments. Default is 2.
7608 Set the number of output video streams, that is also the number of video
7609 streams in each segment. Default is 1.
7612 Set the number of output audio streams, that is also the number of video
7613 streams in each segment. Default is 0.
7616 Activate unsafe mode: do not fail if segments have a different format.
7620 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
7621 @var{a} audio outputs.
7623 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
7624 segment, in the same order as the outputs, then the inputs for the second
7627 Related streams do not always have exactly the same duration, for various
7628 reasons including codec frame size or sloppy authoring. For that reason,
7629 related synchronized streams (e.g. a video and its audio track) should be
7630 concatenated at once. The concat filter will use the duration of the longest
7631 stream in each segment (except the last one), and if necessary pad shorter
7632 audio streams with silence.
7634 For this filter to work correctly, all segments must start at timestamp 0.
7636 All corresponding streams must have the same parameters in all segments; the
7637 filtering system will automatically select a common pixel format for video
7638 streams, and a common sample format, sample rate and channel layout for
7639 audio streams, but other settings, such as resolution, must be converted
7640 explicitly by the user.
7642 Different frame rates are acceptable but will result in variable frame rate
7643 at output; be sure to configure the output file to handle it.
7645 @subsection Examples
7649 Concatenate an opening, an episode and an ending, all in bilingual version
7650 (video in stream 0, audio in streams 1 and 2):
7652 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
7653 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
7654 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
7655 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
7659 Concatenate two parts, handling audio and video separately, using the
7660 (a)movie sources, and adjusting the resolution:
7662 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
7663 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
7664 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
7666 Note that a desync will happen at the stitch if the audio and video streams
7667 do not have exactly the same duration in the first file.
7673 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
7674 it unchanged. By default, it logs a message at a frequency of 10Hz with the
7675 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
7676 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
7678 The filter also has a video output (see the @var{video} option) with a real
7679 time graph to observe the loudness evolution. The graphic contains the logged
7680 message mentioned above, so it is not printed anymore when this option is set,
7681 unless the verbose logging is set. The main graphing area contains the
7682 short-term loudness (3 seconds of analysis), and the gauge on the right is for
7683 the momentary loudness (400 milliseconds).
7685 More information about the Loudness Recommendation EBU R128 on
7686 @url{http://tech.ebu.ch/loudness}.
7688 The filter accepts the following options:
7693 Activate the video output. The audio stream is passed unchanged whether this
7694 option is set or no. The video stream will be the first output stream if
7695 activated. Default is @code{0}.
7698 Set the video size. This option is for video only. Default and minimum
7699 resolution is @code{640x480}.
7702 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
7703 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
7704 other integer value between this range is allowed.
7707 Set metadata injection. If set to @code{1}, the audio input will be segmented
7708 into 100ms output frames, each of them containing various loudness information
7709 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
7711 Default is @code{0}.
7714 Force the frame logging level.
7716 Available values are:
7719 information logging level
7721 verbose logging level
7724 By default, the logging level is set to @var{info}. If the @option{video} or
7725 the @option{metadata} options are set, it switches to @var{verbose}.
7728 @subsection Examples
7732 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
7734 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
7738 Run an analysis with @command{ffmpeg}:
7740 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
7744 @section interleave, ainterleave
7746 Temporally interleave frames from several inputs.
7748 @code{interleave} works with video inputs, @code{ainterleave} with audio.
7750 These filters read frames from several inputs and send the oldest
7751 queued frame to the output.
7753 Input streams must have a well defined, monotonically increasing frame
7756 In order to submit one frame to output, these filters need to enqueue
7757 at least one frame for each input, so they cannot work in case one
7758 input is not yet terminated and will not receive incoming frames.
7760 For example consider the case when one input is a @code{select} filter
7761 which always drop input frames. The @code{interleave} filter will keep
7762 reading from that input, but it will never be able to send new frames
7763 to output until the input will send an end-of-stream signal.
7765 Also, depending on inputs synchronization, the filters will drop
7766 frames in case one input receives more frames than the other ones, and
7767 the queue is already filled.
7769 These filters accept the following options:
7773 Set the number of different inputs, it is 2 by default.
7776 @subsection Examples
7780 Interleave frames belonging to different streams using @command{ffmpeg}:
7782 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
7786 Add flickering blur effect:
7788 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
7792 @section perms, aperms
7794 Set read/write permissions for the output frames.
7796 These filters are mainly aimed at developers to test direct path in the
7797 following filter in the filtergraph.
7799 The filters accept the following options:
7803 Select the permissions mode.
7805 It accepts the following values:
7808 Do nothing. This is the default.
7810 Set all the output frames read-only.
7812 Set all the output frames directly writable.
7814 Make the frame read-only if writable, and writable if read-only.
7816 Set each output frame read-only or writable randomly.
7820 Set the seed for the @var{random} mode, must be an integer included between
7821 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
7822 @code{-1}, the filter will try to use a good random seed on a best effort
7826 Note: in case of auto-inserted filter between the permission filter and the
7827 following one, the permission might not be received as expected in that
7828 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
7829 perms/aperms filter can avoid this problem.
7831 @section select, aselect
7833 Select frames to pass in output.
7835 This filter accepts the following options:
7840 Set expression, which is evaluated for each input frame.
7842 If the expression is evaluated to zero, the frame is discarded.
7844 If the evaluation result is negative or NaN, the frame is sent to the
7845 first output; otherwise it is sent to the output with index
7846 @code{ceil(val)-1}, assuming that the input index starts from 0.
7848 For example a value of @code{1.2} corresponds to the output with index
7849 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
7852 Set the number of outputs. The output to which to send the selected
7853 frame is based on the result of the evaluation. Default value is 1.
7856 The expression can contain the following constants:
7860 the sequential number of the filtered frame, starting from 0
7863 the sequential number of the selected frame, starting from 0
7865 @item prev_selected_n
7866 the sequential number of the last selected frame, NAN if undefined
7869 timebase of the input timestamps
7872 the PTS (Presentation TimeStamp) of the filtered video frame,
7873 expressed in @var{TB} units, NAN if undefined
7876 the PTS (Presentation TimeStamp) of the filtered video frame,
7877 expressed in seconds, NAN if undefined
7880 the PTS of the previously filtered video frame, NAN if undefined
7882 @item prev_selected_pts
7883 the PTS of the last previously filtered video frame, NAN if undefined
7885 @item prev_selected_t
7886 the PTS of the last previously selected video frame, NAN if undefined
7889 the PTS of the first video frame in the video, NAN if undefined
7892 the time of the first video frame in the video, NAN if undefined
7894 @item pict_type @emph{(video only)}
7895 the type of the filtered frame, can assume one of the following
7907 @item interlace_type @emph{(video only)}
7908 the frame interlace type, can assume one of the following values:
7911 the frame is progressive (not interlaced)
7913 the frame is top-field-first
7915 the frame is bottom-field-first
7918 @item consumed_sample_n @emph{(audio only)}
7919 the number of selected samples before the current frame
7921 @item samples_n @emph{(audio only)}
7922 the number of samples in the current frame
7924 @item sample_rate @emph{(audio only)}
7925 the input sample rate
7928 1 if the filtered frame is a key-frame, 0 otherwise
7931 the position in the file of the filtered frame, -1 if the information
7932 is not available (e.g. for synthetic video)
7934 @item scene @emph{(video only)}
7935 value between 0 and 1 to indicate a new scene; a low value reflects a low
7936 probability for the current frame to introduce a new scene, while a higher
7937 value means the current frame is more likely to be one (see the example below)
7941 The default value of the select expression is "1".
7943 @subsection Examples
7947 Select all frames in input:
7952 The example above is the same as:
7964 Select only I-frames:
7966 select='eq(pict_type\,I)'
7970 Select one frame every 100:
7972 select='not(mod(n\,100))'
7976 Select only frames contained in the 10-20 time interval:
7978 select='gte(t\,10)*lte(t\,20)'
7982 Select only I frames contained in the 10-20 time interval:
7984 select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
7988 Select frames with a minimum distance of 10 seconds:
7990 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
7994 Use aselect to select only audio frames with samples number > 100:
7996 aselect='gt(samples_n\,100)'
8000 Create a mosaic of the first scenes:
8002 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
8005 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
8009 Send even and odd frames to separate outputs, and compose them:
8011 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
8015 @section sendcmd, asendcmd
8017 Send commands to filters in the filtergraph.
8019 These filters read commands to be sent to other filters in the
8022 @code{sendcmd} must be inserted between two video filters,
8023 @code{asendcmd} must be inserted between two audio filters, but apart
8024 from that they act the same way.
8026 The specification of commands can be provided in the filter arguments
8027 with the @var{commands} option, or in a file specified by the
8028 @var{filename} option.
8030 These filters accept the following options:
8033 Set the commands to be read and sent to the other filters.
8035 Set the filename of the commands to be read and sent to the other
8039 @subsection Commands syntax
8041 A commands description consists of a sequence of interval
8042 specifications, comprising a list of commands to be executed when a
8043 particular event related to that interval occurs. The occurring event
8044 is typically the current frame time entering or leaving a given time
8047 An interval is specified by the following syntax:
8049 @var{START}[-@var{END}] @var{COMMANDS};
8052 The time interval is specified by the @var{START} and @var{END} times.
8053 @var{END} is optional and defaults to the maximum time.
8055 The current frame time is considered within the specified interval if
8056 it is included in the interval [@var{START}, @var{END}), that is when
8057 the time is greater or equal to @var{START} and is lesser than
8060 @var{COMMANDS} consists of a sequence of one or more command
8061 specifications, separated by ",", relating to that interval. The
8062 syntax of a command specification is given by:
8064 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
8067 @var{FLAGS} is optional and specifies the type of events relating to
8068 the time interval which enable sending the specified command, and must
8069 be a non-null sequence of identifier flags separated by "+" or "|" and
8070 enclosed between "[" and "]".
8072 The following flags are recognized:
8075 The command is sent when the current frame timestamp enters the
8076 specified interval. In other words, the command is sent when the
8077 previous frame timestamp was not in the given interval, and the
8081 The command is sent when the current frame timestamp leaves the
8082 specified interval. In other words, the command is sent when the
8083 previous frame timestamp was in the given interval, and the
8087 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
8090 @var{TARGET} specifies the target of the command, usually the name of
8091 the filter class or a specific filter instance name.
8093 @var{COMMAND} specifies the name of the command for the target filter.
8095 @var{ARG} is optional and specifies the optional list of argument for
8096 the given @var{COMMAND}.
8098 Between one interval specification and another, whitespaces, or
8099 sequences of characters starting with @code{#} until the end of line,
8100 are ignored and can be used to annotate comments.
8102 A simplified BNF description of the commands specification syntax
8105 @var{COMMAND_FLAG} ::= "enter" | "leave"
8106 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
8107 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
8108 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
8109 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
8110 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
8113 @subsection Examples
8117 Specify audio tempo change at second 4:
8119 asendcmd=c='4.0 atempo tempo 1.5',atempo
8123 Specify a list of drawtext and hue commands in a file.
8125 # show text in the interval 5-10
8126 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
8127 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
8129 # desaturate the image in the interval 15-20
8130 15.0-20.0 [enter] hue s 0,
8131 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
8133 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
8135 # apply an exponential saturation fade-out effect, starting from time 25
8136 25 [enter] hue s exp(25-t)
8139 A filtergraph allowing to read and process the above command list
8140 stored in a file @file{test.cmd}, can be specified with:
8142 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
8147 @section setpts, asetpts
8149 Change the PTS (presentation timestamp) of the input frames.
8151 @code{setpts} works on video frames, @code{asetpts} on audio frames.
8153 This filter accepts the following options:
8158 The expression which is evaluated for each frame to construct its timestamp.
8162 The expression is evaluated through the eval API and can contain the following
8167 frame rate, only defined for constant frame-rate video
8170 the presentation timestamp in input
8173 the count of the input frame for video or the number of consumed samples,
8174 not including the current frame for audio, starting from 0.
8176 @item NB_CONSUMED_SAMPLES
8177 the number of consumed samples, not including the current frame (only
8181 the number of samples in the current frame (only audio)
8183 @item SAMPLE_RATE, SR
8187 the PTS of the first frame
8190 the time in seconds of the first frame
8193 tell if the current frame is interlaced
8196 the time in seconds of the current frame
8202 original position in the file of the frame, or undefined if undefined
8203 for the current frame
8209 previous input time in seconds
8215 previous output time in seconds
8218 wallclock (RTC) time in microseconds. This is deprecated, use time(0)
8222 wallclock (RTC) time at the start of the movie in microseconds
8225 @subsection Examples
8229 Start counting PTS from zero
8235 Apply fast motion effect:
8241 Apply slow motion effect:
8247 Set fixed rate of 25 frames per second:
8253 Set fixed rate 25 fps with some jitter:
8255 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
8259 Apply an offset of 10 seconds to the input PTS:
8265 Generate timestamps from a "live source" and rebase onto the current timebase:
8267 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
8271 Generate timestamps by counting samples:
8278 @section settb, asettb
8280 Set the timebase to use for the output frames timestamps.
8281 It is mainly useful for testing timebase configuration.
8283 This filter accepts the following options:
8288 The expression which is evaluated into the output timebase.
8292 The value for @option{tb} is an arithmetic expression representing a
8293 rational. The expression can contain the constants "AVTB" (the default
8294 timebase), "intb" (the input timebase) and "sr" (the sample rate,
8295 audio only). Default value is "intb".
8297 @subsection Examples
8301 Set the timebase to 1/25:
8307 Set the timebase to 1/10:
8313 Set the timebase to 1001/1000:
8319 Set the timebase to 2*intb:
8325 Set the default timebase value:
8331 @section showspectrum
8333 Convert input audio to a video output, representing the audio frequency
8336 The filter accepts the following options:
8340 Specify the video size for the output. Default value is @code{640x512}.
8343 Specify if the spectrum should slide along the window. Default value is
8347 Specify display mode.
8349 It accepts the following values:
8352 all channels are displayed in the same row
8354 all channels are displayed in separate rows
8357 Default value is @samp{combined}.
8360 Specify display color mode.
8362 It accepts the following values:
8365 each channel is displayed in a separate color
8367 each channel is is displayed using the same color scheme
8370 Default value is @samp{channel}.
8373 Specify scale used for calculating intensity color values.
8375 It accepts the following values:
8380 square root, default
8387 Default value is @samp{sqrt}.
8390 Set saturation modifier for displayed colors. Negative values provide
8391 alternative color scheme. @code{0} is no saturation at all.
8392 Saturation must be in [-10.0, 10.0] range.
8393 Default value is @code{1}.
8396 The usage is very similar to the showwaves filter; see the examples in that
8399 @subsection Examples
8403 Large window with logarithmic color scaling:
8405 showspectrum=s=1280x480:scale=log
8409 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
8411 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
8412 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
8418 Convert input audio to a video output, representing the samples waves.
8420 The filter accepts the following options:
8424 Specify the video size for the output. Default value is "600x240".
8429 Available values are:
8432 Draw a point for each sample.
8435 Draw a vertical line for each sample.
8438 Default value is @code{point}.
8441 Set the number of samples which are printed on the same column. A
8442 larger value will decrease the frame rate. Must be a positive
8443 integer. This option can be set only if the value for @var{rate}
8444 is not explicitly specified.
8447 Set the (approximate) output frame rate. This is done by setting the
8448 option @var{n}. Default value is "25".
8452 @subsection Examples
8456 Output the input file audio and the corresponding video representation
8459 amovie=a.mp3,asplit[out0],showwaves[out1]
8463 Create a synthetic signal and show it with showwaves, forcing a
8464 frame rate of 30 frames per second:
8466 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
8470 @section split, asplit
8472 Split input into several identical outputs.
8474 @code{asplit} works with audio input, @code{split} with video.
8476 The filter accepts a single parameter which specifies the number of outputs. If
8477 unspecified, it defaults to 2.
8479 @subsection Examples
8483 Create two separate outputs from the same input:
8485 [in] split [out0][out1]
8489 To create 3 or more outputs, you need to specify the number of
8492 [in] asplit=3 [out0][out1][out2]
8496 Create two separate outputs from the same input, one cropped and
8499 [in] split [splitout1][splitout2];
8500 [splitout1] crop=100:100:0:0 [cropout];
8501 [splitout2] pad=200:200:100:100 [padout];
8505 Create 5 copies of the input audio with @command{ffmpeg}:
8507 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
8513 Receive commands sent through a libzmq client, and forward them to
8514 filters in the filtergraph.
8516 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
8517 must be inserted between two video filters, @code{azmq} between two
8520 To enable these filters you need to install the libzmq library and
8521 headers and configure FFmpeg with @code{--enable-libzmq}.
8523 For more information about libzmq see:
8524 @url{http://www.zeromq.org/}
8526 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
8527 receives messages sent through a network interface defined by the
8528 @option{bind_address} option.
8530 The received message must be in the form:
8532 @var{TARGET} @var{COMMAND} [@var{ARG}]
8535 @var{TARGET} specifies the target of the command, usually the name of
8536 the filter class or a specific filter instance name.
8538 @var{COMMAND} specifies the name of the command for the target filter.
8540 @var{ARG} is optional and specifies the optional argument list for the
8541 given @var{COMMAND}.
8543 Upon reception, the message is processed and the corresponding command
8544 is injected into the filtergraph. Depending on the result, the filter
8545 will send a reply to the client, adopting the format:
8547 @var{ERROR_CODE} @var{ERROR_REASON}
8551 @var{MESSAGE} is optional.
8553 @subsection Examples
8555 Look at @file{tools/zmqsend} for an example of a zmq client which can
8556 be used to send commands processed by these filters.
8558 Consider the following filtergraph generated by @command{ffplay}
8560 ffplay -dumpgraph 1 -f lavfi "
8561 color=s=100x100:c=red [l];
8562 color=s=100x100:c=blue [r];
8563 nullsrc=s=200x100, zmq [bg];
8564 [bg][l] overlay [bg+l];
8565 [bg+l][r] overlay=x=100 "
8568 To change the color of the left side of the video, the following
8569 command can be used:
8571 echo Parsed_color_0 c yellow | tools/zmqsend
8574 To change the right side:
8576 echo Parsed_color_1 c pink | tools/zmqsend
8579 @c man end MULTIMEDIA FILTERS
8581 @chapter Multimedia Sources
8582 @c man begin MULTIMEDIA SOURCES
8584 Below is a description of the currently available multimedia sources.
8588 This is the same as @ref{movie} source, except it selects an audio
8594 Read audio and/or video stream(s) from a movie container.
8596 This filter accepts the following options:
8600 The name of the resource to read (not necessarily a file but also a device or a
8601 stream accessed through some protocol).
8603 @item format_name, f
8604 Specifies the format assumed for the movie to read, and can be either
8605 the name of a container or an input device. If not specified the
8606 format is guessed from @var{movie_name} or by probing.
8608 @item seek_point, sp
8609 Specifies the seek point in seconds, the frames will be output
8610 starting from this seek point, the parameter is evaluated with
8611 @code{av_strtod} so the numerical value may be suffixed by an IS
8612 postfix. Default value is "0".
8615 Specifies the streams to read. Several streams can be specified,
8616 separated by "+". The source will then have as many outputs, in the
8617 same order. The syntax is explained in the ``Stream specifiers''
8618 section in the ffmpeg manual. Two special names, "dv" and "da" specify
8619 respectively the default (best suited) video and audio stream. Default
8620 is "dv", or "da" if the filter is called as "amovie".
8622 @item stream_index, si
8623 Specifies the index of the video stream to read. If the value is -1,
8624 the best suited video stream will be automatically selected. Default
8625 value is "-1". Deprecated. If the filter is called "amovie", it will select
8626 audio instead of video.
8629 Specifies how many times to read the stream in sequence.
8630 If the value is less than 1, the stream will be read again and again.
8631 Default value is "1".
8633 Note that when the movie is looped the source timestamps are not
8634 changed, so it will generate non monotonically increasing timestamps.
8637 This filter allows to overlay a second video on top of main input of
8638 a filtergraph as shown in this graph:
8640 input -----------> deltapts0 --> overlay --> output
8643 movie --> scale--> deltapts1 -------+
8646 @subsection Examples
8650 Skip 3.2 seconds from the start of the avi file in.avi, and overlay it
8651 on top of the input labelled as "in":
8653 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
8654 [in] setpts=PTS-STARTPTS [main];
8655 [main][over] overlay=16:16 [out]
8659 Read from a video4linux2 device, and overlay it on top of the input
8662 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
8663 [in] setpts=PTS-STARTPTS [main];
8664 [main][over] overlay=16:16 [out]
8668 Read the first video stream and the audio stream with id 0x81 from
8669 dvd.vob; the video is connected to the pad named "video" and the audio is
8670 connected to the pad named "audio":
8672 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
8676 @c man end MULTIMEDIA SOURCES