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 The filter accepts the following option:
1932 Set the minimal luminance value. Default is @code{16}.
1935 @section blackdetect
1937 Detect video intervals that are (almost) completely black. Can be
1938 useful to detect chapter transitions, commercials, or invalid
1939 recordings. Output lines contains the time for the start, end and
1940 duration of the detected black interval expressed in seconds.
1942 In order to display the output lines, you need to set the loglevel at
1943 least to the AV_LOG_INFO value.
1945 The filter accepts the following options:
1948 @item black_min_duration, d
1949 Set the minimum detected black duration expressed in seconds. It must
1950 be a non-negative floating point number.
1952 Default value is 2.0.
1954 @item picture_black_ratio_th, pic_th
1955 Set the threshold for considering a picture "black".
1956 Express the minimum value for the ratio:
1958 @var{nb_black_pixels} / @var{nb_pixels}
1961 for which a picture is considered black.
1962 Default value is 0.98.
1964 @item pixel_black_th, pix_th
1965 Set the threshold for considering a pixel "black".
1967 The threshold expresses the maximum pixel luminance value for which a
1968 pixel is considered "black". The provided value is scaled according to
1969 the following equation:
1971 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
1974 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
1975 the input video format, the range is [0-255] for YUV full-range
1976 formats and [16-235] for YUV non full-range formats.
1978 Default value is 0.10.
1981 The following example sets the maximum pixel threshold to the minimum
1982 value, and detects only black intervals of 2 or more seconds:
1984 blackdetect=d=2:pix_th=0.00
1989 Detect frames that are (almost) completely black. Can be useful to
1990 detect chapter transitions or commercials. Output lines consist of
1991 the frame number of the detected frame, the percentage of blackness,
1992 the position in the file if known or -1 and the timestamp in seconds.
1994 In order to display the output lines, you need to set the loglevel at
1995 least to the AV_LOG_INFO value.
1997 The filter accepts the following options:
2002 Set the percentage of the pixels that have to be below the threshold, defaults
2005 @item threshold, thresh
2006 Set the threshold below which a pixel value is considered black, defaults to
2013 Blend two video frames into each other.
2015 It takes two input streams and outputs one stream, the first input is the
2016 "top" layer and second input is "bottom" layer.
2017 Output terminates when shortest input terminates.
2019 A description of the accepted options follows.
2027 Set blend mode for specific pixel component or all pixel components in case
2028 of @var{all_mode}. Default value is @code{normal}.
2030 Available values for component modes are:
2063 Set blend opacity for specific pixel component or all pixel components in case
2064 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2071 Set blend expression for specific pixel component or all pixel components in case
2072 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2074 The expressions can use the following variables:
2078 The sequential number of the filtered frame, starting from @code{0}.
2082 the coordinates of the current sample
2086 the width and height of currently filtered plane
2090 Width and height scale depending on the currently filtered plane. It is the
2091 ratio between the corresponding luma plane number of pixels and the current
2092 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2093 @code{0.5,0.5} for chroma planes.
2096 Time of the current frame, expressed in seconds.
2099 Value of pixel component at current location for first video frame (top layer).
2102 Value of pixel component at current location for second video frame (bottom layer).
2106 @subsection Examples
2110 Apply transition from bottom layer to top layer in first 10 seconds:
2112 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2116 Apply 1x1 checkerboard effect:
2118 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2124 Apply boxblur algorithm to the input video.
2126 The filter accepts the following options:
2130 @item luma_radius, lr
2131 @item luma_power, lp
2132 @item chroma_radius, cr
2133 @item chroma_power, cp
2134 @item alpha_radius, ar
2135 @item alpha_power, ap
2139 A description of the accepted options follows.
2142 @item luma_radius, lr
2143 @item chroma_radius, cr
2144 @item alpha_radius, ar
2145 Set an expression for the box radius in pixels used for blurring the
2146 corresponding input plane.
2148 The radius value must be a non-negative number, and must not be
2149 greater than the value of the expression @code{min(w,h)/2} for the
2150 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2153 Default value for @option{luma_radius} is "2". If not specified,
2154 @option{chroma_radius} and @option{alpha_radius} default to the
2155 corresponding value set for @option{luma_radius}.
2157 The expressions can contain the following constants:
2161 the input width and height in pixels
2165 the input chroma image width and height in pixels
2169 horizontal and vertical chroma subsample values. For example for the
2170 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2173 @item luma_power, lp
2174 @item chroma_power, cp
2175 @item alpha_power, ap
2176 Specify how many times the boxblur filter is applied to the
2177 corresponding plane.
2179 Default value for @option{luma_power} is 2. If not specified,
2180 @option{chroma_power} and @option{alpha_power} default to the
2181 corresponding value set for @option{luma_power}.
2183 A value of 0 will disable the effect.
2186 @subsection Examples
2190 Apply a boxblur filter with luma, chroma, and alpha radius
2193 boxblur=luma_radius=2:luma_power=1
2198 Set luma radius to 2, alpha and chroma radius to 0:
2200 boxblur=2:1:cr=0:ar=0
2204 Set luma and chroma radius to a fraction of the video dimension:
2206 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2210 @section colorbalance
2211 Modify intensity of primary colors (red, green and blue) of input frames.
2213 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2214 regions for the red-cyan, green-magenta or blue-yellow balance.
2216 A positive adjustment value shifts the balance towards the primary color, a negative
2217 value towards the complementary color.
2219 The filter accepts the following options:
2225 Adjust red, green and blue shadows (darkest pixels).
2230 Adjust red, green and blue midtones (medium pixels).
2235 Adjust red, green and blue highlights (brightest pixels).
2237 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2240 @subsection Examples
2244 Add red color cast to shadows:
2250 @section colorchannelmixer
2252 Adjust video input frames by re-mixing color channels.
2254 This filter modifies a color channel by adding the values associated to
2255 the other channels of the same pixels. For example if the value to
2256 modify is red, the output value will be:
2258 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2261 The filter accepts the following options:
2268 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2269 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2275 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2276 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2282 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2283 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2289 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2290 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2292 Allowed ranges for options are @code{[-2.0, 2.0]}.
2295 @subsection Examples
2299 Convert source to grayscale:
2301 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2305 @section colormatrix
2307 Convert color matrix.
2309 The filter accepts the following options:
2314 Specify the source and destination color matrix. Both values must be
2317 The accepted values are:
2333 For example to convert from BT.601 to SMPTE-240M, use the command:
2335 colormatrix=bt601:smpte240m
2340 Copy the input source unchanged to the output. Mainly useful for
2345 Crop the input video to given dimensions.
2347 The filter accepts the following options:
2351 Width of the output video. It defaults to @code{iw}.
2352 This expression is evaluated only once during the filter
2356 Height of the output video. It defaults to @code{ih}.
2357 This expression is evaluated only once during the filter
2361 Horizontal position, in the input video, of the left edge of the output video.
2362 It defaults to @code{(in_w-out_w)/2}.
2363 This expression is evaluated per-frame.
2366 Vertical position, in the input video, of the top edge of the output video.
2367 It defaults to @code{(in_h-out_h)/2}.
2368 This expression is evaluated per-frame.
2371 If set to 1 will force the output display aspect ratio
2372 to be the same of the input, by changing the output sample aspect
2373 ratio. It defaults to 0.
2376 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
2377 expressions containing the following constants:
2382 the computed values for @var{x} and @var{y}. They are evaluated for
2387 the input width and height
2391 same as @var{in_w} and @var{in_h}
2395 the output (cropped) width and height
2399 same as @var{out_w} and @var{out_h}
2402 same as @var{iw} / @var{ih}
2405 input sample aspect ratio
2408 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
2412 horizontal and vertical chroma subsample values. For example for the
2413 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2416 the number of input frame, starting from 0
2419 the position in the file of the input frame, NAN if unknown
2422 timestamp expressed in seconds, NAN if the input timestamp is unknown
2426 The expression for @var{out_w} may depend on the value of @var{out_h},
2427 and the expression for @var{out_h} may depend on @var{out_w}, but they
2428 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
2429 evaluated after @var{out_w} and @var{out_h}.
2431 The @var{x} and @var{y} parameters specify the expressions for the
2432 position of the top-left corner of the output (non-cropped) area. They
2433 are evaluated for each frame. If the evaluated value is not valid, it
2434 is approximated to the nearest valid value.
2436 The expression for @var{x} may depend on @var{y}, and the expression
2437 for @var{y} may depend on @var{x}.
2439 @subsection Examples
2443 Crop area with size 100x100 at position (12,34).
2448 Using named options, the example above becomes:
2450 crop=w=100:h=100:x=12:y=34
2454 Crop the central input area with size 100x100:
2460 Crop the central input area with size 2/3 of the input video:
2462 crop=2/3*in_w:2/3*in_h
2466 Crop the input video central square:
2473 Delimit the rectangle with the top-left corner placed at position
2474 100:100 and the right-bottom corner corresponding to the right-bottom
2475 corner of the input image:
2477 crop=in_w-100:in_h-100:100:100
2481 Crop 10 pixels from the left and right borders, and 20 pixels from
2482 the top and bottom borders
2484 crop=in_w-2*10:in_h-2*20
2488 Keep only the bottom right quarter of the input image:
2490 crop=in_w/2:in_h/2:in_w/2:in_h/2
2494 Crop height for getting Greek harmony:
2496 crop=in_w:1/PHI*in_w
2500 Appply trembling effect:
2502 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)
2506 Apply erratic camera effect depending on timestamp:
2508 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)"
2512 Set x depending on the value of y:
2514 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
2520 Auto-detect crop size.
2522 Calculate necessary cropping parameters and prints the recommended
2523 parameters through the logging system. The detected dimensions
2524 correspond to the non-black area of the input video.
2526 The filter accepts the following options:
2531 Set higher black value threshold, which can be optionally specified
2532 from nothing (0) to everything (255). An intensity value greater
2533 to the set value is considered non-black. Default value is 24.
2536 Set the value for which the width/height should be divisible by. The
2537 offset is automatically adjusted to center the video. Use 2 to get
2538 only even dimensions (needed for 4:2:2 video). 16 is best when
2539 encoding to most video codecs. Default value is 16.
2541 @item reset_count, reset
2542 Set the counter that determines after how many frames cropdetect will
2543 reset the previously detected largest video area and start over to
2544 detect the current optimal crop area. Default value is 0.
2546 This can be useful when channel logos distort the video area. 0
2547 indicates never reset and return the largest area encountered during
2554 Apply color adjustments using curves.
2556 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
2557 component (red, green and blue) has its values defined by @var{N} key points
2558 tied from each other using a smooth curve. The x-axis represents the pixel
2559 values from the input frame, and the y-axis the new pixel values to be set for
2562 By default, a component curve is defined by the two points @var{(0;0)} and
2563 @var{(1;1)}. This creates a straight line where each original pixel value is
2564 "adjusted" to its own value, which means no change to the image.
2566 The filter allows you to redefine these two points and add some more. A new
2567 curve (using a natural cubic spline interpolation) will be define to pass
2568 smoothly through all these new coordinates. The new defined points needs to be
2569 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
2570 be in the @var{[0;1]} interval. If the computed curves happened to go outside
2571 the vector spaces, the values will be clipped accordingly.
2573 If there is no key point defined in @code{x=0}, the filter will automatically
2574 insert a @var{(0;0)} point. In the same way, if there is no key point defined
2575 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
2577 The filter accepts the following options:
2581 Select one of the available color presets. This option can be used in addition
2582 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
2583 options takes priority on the preset values.
2584 Available presets are:
2587 @item color_negative
2590 @item increase_contrast
2592 @item linear_contrast
2593 @item medium_contrast
2595 @item strong_contrast
2598 Default is @code{none}.
2600 Set the master key points. These points will define a second pass mapping. It
2601 is sometimes called a "luminance" or "value" mapping. It can be used with
2602 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
2603 post-processing LUT.
2605 Set the key points for the red component.
2607 Set the key points for the green component.
2609 Set the key points for the blue component.
2611 Set the key points for all components (not including master).
2612 Can be used in addition to the other key points component
2613 options. In this case, the unset component(s) will fallback on this
2614 @option{all} setting.
2616 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
2619 To avoid some filtergraph syntax conflicts, each key points list need to be
2620 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
2622 @subsection Examples
2626 Increase slightly the middle level of blue:
2628 curves=blue='0.5/0.58'
2634 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
2636 Here we obtain the following coordinates for each components:
2639 @code{(0;0.11) (0.42;0.51) (1;0.95)}
2641 @code{(0;0) (0.50;0.48) (1;1)}
2643 @code{(0;0.22) (0.49;0.44) (1;0.80)}
2647 The previous example can also be achieved with the associated built-in preset:
2649 curves=preset=vintage
2659 Use a Photoshop preset and redefine the points of the green component:
2661 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
2667 Denoise frames using 2D DCT (frequency domain filtering).
2669 This filter is not designed for real time and can be extremely slow.
2671 The filter accepts the following options:
2675 Set the noise sigma constant.
2677 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
2678 coefficient (absolute value) below this threshold with be dropped.
2680 If you need a more advanced filtering, see @option{expr}.
2682 Default is @code{0}.
2685 Set number overlapping pixels for each block. Each block is of size
2686 @code{16x16}. Since the filter can be slow, you may want to reduce this value,
2687 at the cost of a less effective filter and the risk of various artefacts.
2689 If the overlapping value doesn't allow to process the whole input width or
2690 height, a warning will be displayed and according borders won't be denoised.
2692 Default value is @code{15}.
2695 Set the coefficient factor expression.
2697 For each coefficient of a DCT block, this expression will be evaluated as a
2698 multiplier value for the coefficient.
2700 If this is option is set, the @option{sigma} option will be ignored.
2702 The absolute value of the coefficient can be accessed through the @var{c}
2706 @subsection Examples
2708 Apply a denoise with a @option{sigma} of @code{4.5}:
2713 The same operation can be achieved using the expression system:
2715 dctdnoiz=e='gte(c, 4.5*3)'
2721 Drop duplicated frames at regular intervals.
2723 The filter accepts the following options:
2727 Set the number of frames from which one will be dropped. Setting this to
2728 @var{N} means one frame in every batch of @var{N} frames will be dropped.
2729 Default is @code{5}.
2732 Set the threshold for duplicate detection. If the difference metric for a frame
2733 is less than or equal to this value, then it is declared as duplicate. Default
2737 Set scene change threshold. Default is @code{15}.
2741 Set the size of the x and y-axis blocks used during metric calculations.
2742 Larger blocks give better noise suppression, but also give worse detection of
2743 small movements. Must be a power of two. Default is @code{32}.
2746 Mark main input as a pre-processed input and activate clean source input
2747 stream. This allows the input to be pre-processed with various filters to help
2748 the metrics calculation while keeping the frame selection lossless. When set to
2749 @code{1}, the first stream is for the pre-processed input, and the second
2750 stream is the clean source from where the kept frames are chosen. Default is
2754 Set whether or not chroma is considered in the metric calculations. Default is
2760 Suppress a TV station logo by a simple interpolation of the surrounding
2761 pixels. Just set a rectangle covering the logo and watch it disappear
2762 (and sometimes something even uglier appear - your mileage may vary).
2764 This filter accepts the following options:
2769 Specify the top left corner coordinates of the logo. They must be
2774 Specify the width and height of the logo to clear. They must be
2778 Specify the thickness of the fuzzy edge of the rectangle (added to
2779 @var{w} and @var{h}). The default value is 4.
2782 When set to 1, a green rectangle is drawn on the screen to simplify
2783 finding the right @var{x}, @var{y}, @var{w}, @var{h} parameters, and
2784 @var{band} is set to 4. The default value is 0.
2788 @subsection Examples
2792 Set a rectangle covering the area with top left corner coordinates 0,0
2793 and size 100x77, setting a band of size 10:
2795 delogo=x=0:y=0:w=100:h=77:band=10
2802 Attempt to fix small changes in horizontal and/or vertical shift. This
2803 filter helps remove camera shake from hand-holding a camera, bumping a
2804 tripod, moving on a vehicle, etc.
2806 The filter accepts the following options:
2814 Specify a rectangular area where to limit the search for motion
2816 If desired the search for motion vectors can be limited to a
2817 rectangular area of the frame defined by its top left corner, width
2818 and height. These parameters have the same meaning as the drawbox
2819 filter which can be used to visualise the position of the bounding
2822 This is useful when simultaneous movement of subjects within the frame
2823 might be confused for camera motion by the motion vector search.
2825 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
2826 then the full frame is used. This allows later options to be set
2827 without specifying the bounding box for the motion vector search.
2829 Default - search the whole frame.
2833 Specify the maximum extent of movement in x and y directions in the
2834 range 0-64 pixels. Default 16.
2837 Specify how to generate pixels to fill blanks at the edge of the
2838 frame. Available values are:
2841 Fill zeroes at blank locations
2843 Original image at blank locations
2845 Extruded edge value at blank locations
2847 Mirrored edge at blank locations
2849 Default value is @samp{mirror}.
2852 Specify the blocksize to use for motion search. Range 4-128 pixels,
2856 Specify the contrast threshold for blocks. Only blocks with more than
2857 the specified contrast (difference between darkest and lightest
2858 pixels) will be considered. Range 1-255, default 125.
2861 Specify the search strategy. Available values are:
2864 Set exhaustive search
2866 Set less exhaustive search.
2868 Default value is @samp{exhaustive}.
2871 If set then a detailed log of the motion search is written to the
2875 If set to 1, specify using OpenCL capabilities, only available if
2876 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
2882 Draw a colored box on the input image.
2884 This filter accepts the following options:
2889 Specify the top left corner coordinates of the box. Default to 0.
2893 Specify the width and height of the box, if 0 they are interpreted as
2894 the input width and height. Default to 0.
2897 Specify the color of the box to write, it can be the name of a color
2898 (case insensitive match) or a 0xRRGGBB[AA] sequence. If the special
2899 value @code{invert} is used, the box edge color is the same as the
2900 video with inverted luma.
2903 Set the thickness of the box edge. Default value is @code{4}.
2906 @subsection Examples
2910 Draw a black box around the edge of the input image:
2916 Draw a box with color red and an opacity of 50%:
2918 drawbox=10:20:200:60:red@@0.5
2921 The previous example can be specified as:
2923 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
2927 Fill the box with pink color:
2929 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
2935 Draw a grid on the input image.
2937 This filter accepts the following options:
2942 Specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
2946 Specify the width and height of the grid cell, if 0 they are interpreted as the
2947 input width and height, respectively, minus @code{thickness}, so image gets
2948 framed. Default to 0.
2951 Specify the color of the grid, it can be the name of a color
2952 (case insensitive match) or a 0xRRGGBB[AA] sequence. If the special
2953 value @code{invert} is used, the grid color is the same as the
2954 video with inverted luma.
2955 Note that you can append opacity value (in range of 0.0 - 1.0)
2956 to color name after @@ sign.
2959 Set the thickness of the grid line. Default value is @code{1}.
2962 @subsection Examples
2966 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
2968 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
2975 Draw text string or text from specified file on top of video using the
2976 libfreetype library.
2978 To enable compilation of this filter you need to configure FFmpeg with
2979 @code{--enable-libfreetype}.
2983 The description of the accepted parameters follows.
2988 Used to draw a box around text using background color.
2989 Value should be either 1 (enable) or 0 (disable).
2990 The default value of @var{box} is 0.
2993 The color to be used for drawing box around text.
2994 Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
2995 (e.g. "0xff00ff"), possibly followed by an alpha specifier.
2996 The default value of @var{boxcolor} is "white".
2999 Set an expression which specifies if the text should be drawn. If the
3000 expression evaluates to 0, the text is not drawn. This is useful for
3001 specifying that the text should be drawn only when specific conditions
3004 Default value is "1".
3006 See below for the list of accepted constants and functions.
3009 Select how the @var{text} is expanded. Can be either @code{none},
3010 @code{strftime} (deprecated) or
3011 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3015 If true, check and fix text coords to avoid clipping.
3018 The color to be used for drawing fonts.
3019 Either a string (e.g. "red") or in 0xRRGGBB[AA] format
3020 (e.g. "0xff000033"), possibly followed by an alpha specifier.
3021 The default value of @var{fontcolor} is "black".
3024 The font file to be used for drawing text. Path must be included.
3025 This parameter is mandatory.
3028 The font size to be used for drawing text.
3029 The default value of @var{fontsize} is 16.
3032 Flags to be used for loading the fonts.
3034 The flags map the corresponding flags supported by libfreetype, and are
3035 a combination of the following values:
3042 @item vertical_layout
3043 @item force_autohint
3046 @item ignore_global_advance_width
3048 @item ignore_transform
3054 Default value is "render".
3056 For more information consult the documentation for the FT_LOAD_*
3060 The color to be used for drawing a shadow behind the drawn text. It
3061 can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
3062 form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
3063 The default value of @var{shadowcolor} is "black".
3067 The x and y offsets for the text shadow position with respect to the
3068 position of the text. They can be either positive or negative
3069 values. Default value for both is "0".
3072 The size in number of spaces to use for rendering the tab.
3076 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3077 format. It can be used with or without text parameter. @var{timecode_rate}
3078 option must be specified.
3080 @item timecode_rate, rate, r
3081 Set the timecode frame rate (timecode only).
3084 The text string to be drawn. The text must be a sequence of UTF-8
3086 This parameter is mandatory if no file is specified with the parameter
3090 A text file containing text to be drawn. The text must be a sequence
3091 of UTF-8 encoded characters.
3093 This parameter is mandatory if no text string is specified with the
3094 parameter @var{text}.
3096 If both @var{text} and @var{textfile} are specified, an error is thrown.
3099 If set to 1, the @var{textfile} will be reloaded before each frame.
3100 Be sure to update it atomically, or it may be read partially, or even fail.
3104 The expressions which specify the offsets where text will be drawn
3105 within the video frame. They are relative to the top/left border of the
3108 The default value of @var{x} and @var{y} is "0".
3110 See below for the list of accepted constants and functions.
3113 The parameters for @var{x} and @var{y} are expressions containing the
3114 following constants and functions:
3118 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3122 horizontal and vertical chroma subsample values. For example for the
3123 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3126 the height of each text line
3134 @item max_glyph_a, ascent
3135 the maximum distance from the baseline to the highest/upper grid
3136 coordinate used to place a glyph outline point, for all the rendered
3138 It is a positive value, due to the grid's orientation with the Y axis
3141 @item max_glyph_d, descent
3142 the maximum distance from the baseline to the lowest grid coordinate
3143 used to place a glyph outline point, for all the rendered glyphs.
3144 This is a negative value, due to the grid's orientation, with the Y axis
3148 maximum glyph height, that is the maximum height for all the glyphs
3149 contained in the rendered text, it is equivalent to @var{ascent} -
3153 maximum glyph width, that is the maximum width for all the glyphs
3154 contained in the rendered text
3157 the number of input frame, starting from 0
3159 @item rand(min, max)
3160 return a random number included between @var{min} and @var{max}
3163 input sample aspect ratio
3166 timestamp expressed in seconds, NAN if the input timestamp is unknown
3169 the height of the rendered text
3172 the width of the rendered text
3176 the x and y offset coordinates where the text is drawn.
3178 These parameters allow the @var{x} and @var{y} expressions to refer
3179 each other, so you can for example specify @code{y=x/dar}.
3182 If libavfilter was built with @code{--enable-fontconfig}, then
3183 @option{fontfile} can be a fontconfig pattern or omitted.
3185 @anchor{drawtext_expansion}
3186 @subsection Text expansion
3188 If @option{expansion} is set to @code{strftime},
3189 the filter recognizes strftime() sequences in the provided text and
3190 expands them accordingly. Check the documentation of strftime(). This
3191 feature is deprecated.
3193 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3195 If @option{expansion} is set to @code{normal} (which is the default),
3196 the following expansion mechanism is used.
3198 The backslash character '\', followed by any character, always expands to
3199 the second character.
3201 Sequence of the form @code{%@{...@}} are expanded. The text between the
3202 braces is a function name, possibly followed by arguments separated by ':'.
3203 If the arguments contain special characters or delimiters (':' or '@}'),
3204 they should be escaped.
3206 Note that they probably must also be escaped as the value for the
3207 @option{text} option in the filter argument string and as the filter
3208 argument in the filtergraph description, and possibly also for the shell,
3209 that makes up to four levels of escaping; using a text file avoids these
3212 The following functions are available:
3217 The expression evaluation result.
3219 It must take one argument specifying the expression to be evaluated,
3220 which accepts the same constants and functions as the @var{x} and
3221 @var{y} values. Note that not all constants should be used, for
3222 example the text size is not known when evaluating the expression, so
3223 the constants @var{text_w} and @var{text_h} will have an undefined
3227 The time at which the filter is running, expressed in UTC.
3228 It can accept an argument: a strftime() format string.
3231 The time at which the filter is running, expressed in the local time zone.
3232 It can accept an argument: a strftime() format string.
3235 The frame number, starting from 0.
3238 A 1 character description of the current picture type.
3241 The timestamp of the current frame, in seconds, with microsecond accuracy.
3245 @subsection Examples
3249 Draw "Test Text" with font FreeSerif, using the default values for the
3250 optional parameters.
3253 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
3257 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
3258 and y=50 (counting from the top-left corner of the screen), text is
3259 yellow with a red box around it. Both the text and the box have an
3263 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
3264 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
3267 Note that the double quotes are not necessary if spaces are not used
3268 within the parameter list.
3271 Show the text at the center of the video frame:
3273 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
3277 Show a text line sliding from right to left in the last row of the video
3278 frame. The file @file{LONG_LINE} is assumed to contain a single line
3281 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
3285 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
3287 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
3291 Draw a single green letter "g", at the center of the input video.
3292 The glyph baseline is placed at half screen height.
3294 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
3298 Show text for 1 second every 3 seconds:
3300 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:draw=lt(mod(t\,3)\,1):text='blink'"
3304 Use fontconfig to set the font. Note that the colons need to be escaped.
3306 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
3310 Print the date of a real-time encoding (see strftime(3)):
3312 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
3317 For more information about libfreetype, check:
3318 @url{http://www.freetype.org/}.
3320 For more information about fontconfig, check:
3321 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
3325 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
3327 The filter accepts the following options:
3332 Set low and high threshold values used by the Canny thresholding
3335 The high threshold selects the "strong" edge pixels, which are then
3336 connected through 8-connectivity with the "weak" edge pixels selected
3337 by the low threshold.
3339 @var{low} and @var{high} threshold values must be choosen in the range
3340 [0,1], and @var{low} should be lesser or equal to @var{high}.
3342 Default value for @var{low} is @code{20/255}, and default value for @var{high}
3348 edgedetect=low=0.1:high=0.4
3351 @section extractplanes
3353 Extract color channel components from input video stream into
3354 separate grayscale video streams.
3356 The filter accepts the following option:
3360 Set plane(s) to extract.
3362 Available values for planes are:
3373 Choosing planes not available in the input will result in an error.
3374 That means you cannot select @code{r}, @code{g}, @code{b} planes
3375 with @code{y}, @code{u}, @code{v} planes at same time.
3378 @subsection Examples
3382 Extract luma, u and v color channel component from input video frame
3383 into 3 grayscale outputs:
3385 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
3391 Apply fade-in/out effect to input video.
3393 This filter accepts the following options:
3397 The effect type -- can be either "in" for fade-in, or "out" for a fade-out
3399 Default is @code{in}.
3401 @item start_frame, s
3402 Specify the number of the start frame for starting to apply the fade
3403 effect. Default is 0.
3406 The number of frames for which the fade effect has to last. At the end of the
3407 fade-in effect the output video will have the same intensity as the input video,
3408 at the end of the fade-out transition the output video will be completely black.
3412 If set to 1, fade only alpha channel, if one exists on the input.
3415 @item start_time, st
3416 Specify the timestamp (in seconds) of the frame to start to apply the fade
3417 effect. If both start_frame and start_time are specified, the fade will start at
3418 whichever comes last. Default is 0.
3421 The number of seconds for which the fade effect has to last. At the end of the
3422 fade-in effect the output video will have the same intensity as the input video,
3423 at the end of the fade-out transition the output video will be completely black.
3424 If both duration and nb_frames are specified, duration is used. Default is 0.
3427 @subsection Examples
3431 Fade in first 30 frames of video:
3436 The command above is equivalent to:
3442 Fade out last 45 frames of a 200-frame video:
3445 fade=type=out:start_frame=155:nb_frames=45
3449 Fade in first 25 frames and fade out last 25 frames of a 1000-frame video:
3451 fade=in:0:25, fade=out:975:25
3455 Make first 5 frames black, then fade in from frame 5-24:
3461 Fade in alpha over first 25 frames of video:
3463 fade=in:0:25:alpha=1
3467 Make first 5.5 seconds black, then fade in for 0.5 seconds:
3469 fade=t=in:st=5.5:d=0.5
3476 Extract a single field from an interlaced image using stride
3477 arithmetic to avoid wasting CPU time. The output frames are marked as
3480 The filter accepts the following options:
3484 Specify whether to extract the top (if the value is @code{0} or
3485 @code{top}) or the bottom field (if the value is @code{1} or
3491 Field matching filter for inverse telecine. It is meant to reconstruct the
3492 progressive frames from a telecined stream. The filter does not drop duplicated
3493 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
3494 followed by a decimation filter such as @ref{decimate} in the filtergraph.
3496 The separation of the field matching and the decimation is notably motivated by
3497 the possibility of inserting a de-interlacing filter fallback between the two.
3498 If the source has mixed telecined and real interlaced content,
3499 @code{fieldmatch} will not be able to match fields for the interlaced parts.
3500 But these remaining combed frames will be marked as interlaced, and thus can be
3501 de-interlaced by a later filter such as @ref{yadif} before decimation.
3503 In addition to the various configuration options, @code{fieldmatch} can take an
3504 optional second stream, activated through the @option{ppsrc} option. If
3505 enabled, the frames reconstruction will be based on the fields and frames from
3506 this second stream. This allows the first input to be pre-processed in order to
3507 help the various algorithms of the filter, while keeping the output lossless
3508 (assuming the fields are matched properly). Typically, a field-aware denoiser,
3509 or brightness/contrast adjustments can help.
3511 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
3512 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
3513 which @code{fieldmatch} is based on. While the semantic and usage are very
3514 close, some behaviour and options names can differ.
3516 The filter accepts the following options:
3520 Specify the assumed field order of the input stream. Available values are:
3524 Auto detect parity (use FFmpeg's internal parity value).
3526 Assume bottom field first.
3528 Assume top field first.
3531 Note that it is sometimes recommended not to trust the parity announced by the
3534 Default value is @var{auto}.
3537 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
3538 sense that it wont risk creating jerkiness due to duplicate frames when
3539 possible, but if there are bad edits or blended fields it will end up
3540 outputting combed frames when a good match might actually exist. On the other
3541 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
3542 but will almost always find a good frame if there is one. The other values are
3543 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
3544 jerkiness and creating duplicate frames versus finding good matches in sections
3545 with bad edits, orphaned fields, blended fields, etc.
3547 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
3549 Available values are:
3553 2-way matching (p/c)
3555 2-way matching, and trying 3rd match if still combed (p/c + n)
3557 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
3559 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
3560 still combed (p/c + n + u/b)
3562 3-way matching (p/c/n)
3564 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
3565 detected as combed (p/c/n + u/b)
3568 The parenthesis at the end indicate the matches that would be used for that
3569 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
3572 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
3575 Default value is @var{pc_n}.
3578 Mark the main input stream as a pre-processed input, and enable the secondary
3579 input stream as the clean source to pick the fields from. See the filter
3580 introduction for more details. It is similar to the @option{clip2} feature from
3583 Default value is @code{0} (disabled).
3586 Set the field to match from. It is recommended to set this to the same value as
3587 @option{order} unless you experience matching failures with that setting. In
3588 certain circumstances changing the field that is used to match from can have a
3589 large impact on matching performance. Available values are:
3593 Automatic (same value as @option{order}).
3595 Match from the bottom field.
3597 Match from the top field.
3600 Default value is @var{auto}.
3603 Set whether or not chroma is included during the match comparisons. In most
3604 cases it is recommended to leave this enabled. You should set this to @code{0}
3605 only if your clip has bad chroma problems such as heavy rainbowing or other
3606 artifacts. Setting this to @code{0} could also be used to speed things up at
3607 the cost of some accuracy.
3609 Default value is @code{1}.
3613 These define an exclusion band which excludes the lines between @option{y0} and
3614 @option{y1} from being included in the field matching decision. An exclusion
3615 band can be used to ignore subtitles, a logo, or other things that may
3616 interfere with the matching. @option{y0} sets the starting scan line and
3617 @option{y1} sets the ending line; all lines in between @option{y0} and
3618 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
3619 @option{y0} and @option{y1} to the same value will disable the feature.
3620 @option{y0} and @option{y1} defaults to @code{0}.
3623 Set the scene change detection threshold as a percentage of maximum change on
3624 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
3625 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
3626 @option{scthresh} is @code{[0.0, 100.0]}.
3628 Default value is @code{12.0}.
3631 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
3632 account the combed scores of matches when deciding what match to use as the
3633 final match. Available values are:
3637 No final matching based on combed scores.
3639 Combed scores are only used when a scene change is detected.
3641 Use combed scores all the time.
3644 Default is @var{sc}.
3647 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
3648 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
3649 Available values are:
3653 No forced calculation.
3655 Force p/c/n calculations.
3657 Force p/c/n/u/b calculations.
3660 Default value is @var{none}.
3663 This is the area combing threshold used for combed frame detection. This
3664 essentially controls how "strong" or "visible" combing must be to be detected.
3665 Larger values mean combing must be more visible and smaller values mean combing
3666 can be less visible or strong and still be detected. Valid settings are from
3667 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
3668 be detected as combed). This is basically a pixel difference value. A good
3669 range is @code{[8, 12]}.
3671 Default value is @code{9}.
3674 Sets whether or not chroma is considered in the combed frame decision. Only
3675 disable this if your source has chroma problems (rainbowing, etc.) that are
3676 causing problems for the combed frame detection with chroma enabled. Actually,
3677 using @option{chroma}=@var{0} is usually more reliable, except for the case
3678 where there is chroma only combing in the source.
3680 Default value is @code{0}.
3684 Respectively set the x-axis and y-axis size of the window used during combed
3685 frame detection. This has to do with the size of the area in which
3686 @option{combpel} pixels are required to be detected as combed for a frame to be
3687 declared combed. See the @option{combpel} parameter description for more info.
3688 Possible values are any number that is a power of 2 starting at 4 and going up
3691 Default value is @code{16}.
3694 The number of combed pixels inside any of the @option{blocky} by
3695 @option{blockx} size blocks on the frame for the frame to be detected as
3696 combed. While @option{cthresh} controls how "visible" the combing must be, this
3697 setting controls "how much" combing there must be in any localized area (a
3698 window defined by the @option{blockx} and @option{blocky} settings) on the
3699 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
3700 which point no frames will ever be detected as combed). This setting is known
3701 as @option{MI} in TFM/VFM vocabulary.
3703 Default value is @code{80}.
3706 @anchor{p/c/n/u/b meaning}
3707 @subsection p/c/n/u/b meaning
3709 @subsubsection p/c/n
3711 We assume the following telecined stream:
3714 Top fields: 1 2 2 3 4
3715 Bottom fields: 1 2 3 4 4
3718 The numbers correspond to the progressive frame the fields relate to. Here, the
3719 first two frames are progressive, the 3rd and 4th are combed, and so on.
3721 When @code{fieldmatch} is configured to run a matching from bottom
3722 (@option{field}=@var{bottom}) this is how this input stream get transformed:
3727 B 1 2 3 4 4 <-- matching reference
3736 As a result of the field matching, we can see that some frames get duplicated.
3737 To perform a complete inverse telecine, you need to rely on a decimation filter
3738 after this operation. See for instance the @ref{decimate} filter.
3740 The same operation now matching from top fields (@option{field}=@var{top})
3745 T 1 2 2 3 4 <-- matching reference
3755 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
3756 basically, they refer to the frame and field of the opposite parity:
3759 @item @var{p} matches the field of the opposite parity in the previous frame
3760 @item @var{c} matches the field of the opposite parity in the current frame
3761 @item @var{n} matches the field of the opposite parity in the next frame
3766 The @var{u} and @var{b} matching are a bit special in the sense that they match
3767 from the opposite parity flag. In the following examples, we assume that we are
3768 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
3769 'x' is placed above and below each matched fields.
3771 With bottom matching (@option{field}=@var{bottom}):
3776 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
3777 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
3785 With top matching (@option{field}=@var{top}):
3790 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
3791 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
3799 @subsection Examples
3801 Simple IVTC of a top field first telecined stream:
3803 fieldmatch=order=tff:combmatch=none, decimate
3806 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
3808 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
3813 Transform the field order of the input video.
3815 This filter accepts the following options:
3820 Output field order. Valid values are @var{tff} for top field first or @var{bff}
3821 for bottom field first.
3824 Default value is @samp{tff}.
3826 Transformation is achieved by shifting the picture content up or down
3827 by one line, and filling the remaining line with appropriate picture content.
3828 This method is consistent with most broadcast field order converters.
3830 If the input video is not flagged as being interlaced, or it is already
3831 flagged as being of the required output field order then this filter does
3832 not alter the incoming video.
3834 This filter is very useful when converting to or from PAL DV material,
3835 which is bottom field first.
3839 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
3844 Buffer input images and send them when they are requested.
3846 This filter is mainly useful when auto-inserted by the libavfilter
3849 The filter does not take parameters.
3854 Convert the input video to one of the specified pixel formats.
3855 Libavfilter will try to pick one that is supported for the input to
3858 This filter accepts the following parameters:
3862 A '|'-separated list of pixel format names, for example
3863 "pix_fmts=yuv420p|monow|rgb24".
3867 @subsection Examples
3871 Convert the input video to the format @var{yuv420p}
3873 format=pix_fmts=yuv420p
3876 Convert the input video to any of the formats in the list
3878 format=pix_fmts=yuv420p|yuv444p|yuv410p
3884 Convert the video to specified constant frame rate by duplicating or dropping
3885 frames as necessary.
3887 This filter accepts the following named parameters:
3891 Desired output frame rate. The default is @code{25}.
3896 Possible values are:
3899 zero round towards 0
3903 round towards -infinity
3905 round towards +infinity
3909 The default is @code{near}.
3913 Alternatively, the options can be specified as a flat string:
3914 @var{fps}[:@var{round}].
3916 See also the @ref{setpts} filter.
3918 @subsection Examples
3922 A typical usage in order to set the fps to 25:
3928 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
3930 fps=fps=film:round=near
3936 Select one frame every N-th frame.
3938 This filter accepts the following option:
3941 Select frame after every @code{step} frames.
3942 Allowed values are positive integers higher than 0. Default value is @code{1}.
3948 Apply a frei0r effect to the input video.
3950 To enable compilation of this filter you need to install the frei0r
3951 header and configure FFmpeg with @code{--enable-frei0r}.
3953 This filter accepts the following options:
3958 The name to the frei0r effect to load. If the environment variable
3959 @env{FREI0R_PATH} is defined, the frei0r effect is searched in each one of the
3960 directories specified by the colon separated list in @env{FREIOR_PATH},
3961 otherwise in the standard frei0r paths, which are in this order:
3962 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
3963 @file{/usr/lib/frei0r-1/}.
3966 A '|'-separated list of parameters to pass to the frei0r effect.
3970 A frei0r effect parameter can be a boolean (whose values are specified
3971 with "y" and "n"), a double, a color (specified by the syntax
3972 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
3973 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
3974 description), a position (specified by the syntax @var{X}/@var{Y},
3975 @var{X} and @var{Y} being float numbers) and a string.
3977 The number and kind of parameters depend on the loaded effect. If an
3978 effect parameter is not specified the default value is set.
3980 @subsection Examples
3984 Apply the distort0r effect, set the first two double parameters:
3986 frei0r=filter_name=distort0r:filter_params=0.5|0.01
3990 Apply the colordistance effect, take a color as first parameter:
3992 frei0r=colordistance:0.2/0.3/0.4
3993 frei0r=colordistance:violet
3994 frei0r=colordistance:0x112233
3998 Apply the perspective effect, specify the top left and top right image
4001 frei0r=perspective:0.2/0.2|0.8/0.2
4005 For more information see:
4006 @url{http://frei0r.dyne.org}
4010 The filter accepts the following options:
4014 Set the luminance expression.
4016 Set the chrominance blue expression.
4018 Set the chrominance red expression.
4020 Set the alpha expression.
4022 Set the red expression.
4024 Set the green expression.
4026 Set the blue expression.
4029 The colorspace is selected according to the specified options. If one
4030 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4031 options is specified, the filter will automatically select a YCbCr
4032 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4033 @option{blue_expr} options is specified, it will select an RGB
4036 If one of the chrominance expression is not defined, it falls back on the other
4037 one. If no alpha expression is specified it will evaluate to opaque value.
4038 If none of chrominance expressions are specified, they will evaluate
4039 to the luminance expression.
4041 The expressions can use the following variables and functions:
4045 The sequential number of the filtered frame, starting from @code{0}.
4049 The coordinates of the current sample.
4053 The width and height of the image.
4057 Width and height scale depending on the currently filtered plane. It is the
4058 ratio between the corresponding luma plane number of pixels and the current
4059 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4060 @code{0.5,0.5} for chroma planes.
4063 Time of the current frame, expressed in seconds.
4066 Return the value of the pixel at location (@var{x},@var{y}) of the current
4070 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
4074 Return the value of the pixel at location (@var{x},@var{y}) of the
4075 blue-difference chroma plane. Return 0 if there is no such plane.
4078 Return the value of the pixel at location (@var{x},@var{y}) of the
4079 red-difference chroma plane. Return 0 if there is no such plane.
4084 Return the value of the pixel at location (@var{x},@var{y}) of the
4085 red/green/blue component. Return 0 if there is no such component.
4088 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
4089 plane. Return 0 if there is no such plane.
4092 For functions, if @var{x} and @var{y} are outside the area, the value will be
4093 automatically clipped to the closer edge.
4095 @subsection Examples
4099 Flip the image horizontally:
4105 Generate a bidimensional sine wave, with angle @code{PI/3} and a
4106 wavelength of 100 pixels:
4108 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
4112 Generate a fancy enigmatic moving light:
4114 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
4118 Generate a quick emboss effect:
4120 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
4124 Modify RGB components depending on pixel position:
4126 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
4132 Fix the banding artifacts that are sometimes introduced into nearly flat
4133 regions by truncation to 8bit color depth.
4134 Interpolate the gradients that should go where the bands are, and
4137 This filter is designed for playback only. Do not use it prior to
4138 lossy compression, because compression tends to lose the dither and
4139 bring back the bands.
4141 This filter accepts the following options:
4146 The maximum amount by which the filter will change any one pixel. Also the
4147 threshold for detecting nearly flat regions. Acceptable values range from .51 to
4148 64, default value is 1.2, out-of-range values will be clipped to the valid
4152 The neighborhood to fit the gradient to. A larger radius makes for smoother
4153 gradients, but also prevents the filter from modifying the pixels near detailed
4154 regions. Acceptable values are 8-32, default value is 16, out-of-range values
4155 will be clipped to the valid range.
4159 Alternatively, the options can be specified as a flat string:
4160 @var{strength}[:@var{radius}]
4162 @subsection Examples
4166 Apply the filter with a @code{3.5} strength and radius of @code{8}:
4172 Specify radius, omitting the strength (which will fall-back to the default
4183 Apply a Hald CLUT to a video stream.
4185 First input is the video stream to process, and second one is the Hald CLUT.
4186 The Hald CLUT input can be a simple picture or a complete video stream.
4188 The filter accepts the following options:
4192 Force termination when the shortest input terminates. Default is @code{0}.
4194 Continue applying the last CLUT after the end of the stream. A value of
4195 @code{0} disable the filter after the last frame of the CLUT is reached.
4196 Default is @code{1}.
4199 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
4200 filters share the same internals).
4202 More information about the Hald CLUT can be found on Eskil Steenberg's website
4203 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
4205 @subsection Workflow examples
4207 @subsubsection Hald CLUT video stream
4209 Generate an identity Hald CLUT stream altered with various effects:
4211 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "hue=H=2*PI*t:s=sin(2*PI*t)+1, curves=cross_process" -t 10 -c:v ffv1 clut.nut
4214 Note: make sure you use a lossless codec.
4216 Then use it with @code{haldclut} to apply it on some random stream:
4218 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
4221 The Hald CLUT will be applied to the 10 first seconds (duration of
4222 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
4223 to the remaining frames of the @code{mandelbrot} stream.
4225 @subsubsection Hald CLUT with preview
4227 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
4228 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
4229 biggest possible square starting at the top left of the picture. The remaining
4230 padding pixels (bottom or right) will be ignored. This area can be used to add
4231 a preview of the Hald CLUT.
4233 Typically, the following generated Hald CLUT will be supported by the
4234 @code{haldclut} filter:
4237 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
4238 pad=iw+320 [padded_clut];
4239 smptebars=s=320x256, split [a][b];
4240 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
4241 [main][b] overlay=W-320" -frames:v 1 clut.png
4244 It contains the original and a preview of the effect of the CLUT: SMPTE color
4245 bars are displayed on the right-top, and below the same color bars processed by
4248 Then, the effect of this Hald CLUT can be visualized with:
4250 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
4255 Flip the input video horizontally.
4257 For example to horizontally flip the input video with @command{ffmpeg}:
4259 ffmpeg -i in.avi -vf "hflip" out.avi
4263 This filter applies a global color histogram equalization on a
4266 It can be used to correct video that has a compressed range of pixel
4267 intensities. The filter redistributes the pixel intensities to
4268 equalize their distribution across the intensity range. It may be
4269 viewed as an "automatically adjusting contrast filter". This filter is
4270 useful only for correcting degraded or poorly captured source
4273 The filter accepts the following options:
4277 Determine the amount of equalization to be applied. As the strength
4278 is reduced, the distribution of pixel intensities more-and-more
4279 approaches that of the input frame. The value must be a float number
4280 in the range [0,1] and defaults to 0.200.
4283 Set the maximum intensity that can generated and scale the output
4284 values appropriately. The strength should be set as desired and then
4285 the intensity can be limited if needed to avoid washing-out. The value
4286 must be a float number in the range [0,1] and defaults to 0.210.
4289 Set the antibanding level. If enabled the filter will randomly vary
4290 the luminance of output pixels by a small amount to avoid banding of
4291 the histogram. Possible values are @code{none}, @code{weak} or
4292 @code{strong}. It defaults to @code{none}.
4297 Compute and draw a color distribution histogram for the input video.
4299 The computed histogram is a representation of distribution of color components
4302 The filter accepts the following options:
4308 It accepts the following values:
4311 standard histogram that display color components distribution in an image.
4312 Displays color graph for each color component. Shows distribution
4313 of the Y, U, V, A or G, B, R components, depending on input format,
4314 in current frame. Bellow each graph is color component scale meter.
4317 chroma values in vectorscope, if brighter more such chroma values are
4318 distributed in an image.
4319 Displays chroma values (U/V color placement) in two dimensional graph
4320 (which is called a vectorscope). It can be used to read of the hue and
4321 saturation of the current frame. At a same time it is a histogram.
4322 The whiter a pixel in the vectorscope, the more pixels of the input frame
4323 correspond to that pixel (that is the more pixels have this chroma value).
4324 The V component is displayed on the horizontal (X) axis, with the leftmost
4325 side being V = 0 and the rightmost side being V = 255.
4326 The U component is displayed on the vertical (Y) axis, with the top
4327 representing U = 0 and the bottom representing U = 255.
4329 The position of a white pixel in the graph corresponds to the chroma value
4330 of a pixel of the input clip. So the graph can be used to read of the
4331 hue (color flavor) and the saturation (the dominance of the hue in the color).
4332 As the hue of a color changes, it moves around the square. At the center of
4333 the square, the saturation is zero, which means that the corresponding pixel
4334 has no color. If you increase the amount of a specific color, while leaving
4335 the other colors unchanged, the saturation increases, and you move towards
4336 the edge of the square.
4339 chroma values in vectorscope, similar as @code{color} but actual chroma values
4343 per row/column color component graph. In row mode graph in the left side represents
4344 color component value 0 and right side represents value = 255. In column mode top
4345 side represents color component value = 0 and bottom side represents value = 255.
4347 Default value is @code{levels}.
4350 Set height of level in @code{levels}. Default value is @code{200}.
4351 Allowed range is [50, 2048].
4354 Set height of color scale in @code{levels}. Default value is @code{12}.
4355 Allowed range is [0, 40].
4358 Set step for @code{waveform} mode. Smaller values are useful to find out how much
4359 of same luminance values across input rows/columns are distributed.
4360 Default value is @code{10}. Allowed range is [1, 255].
4363 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
4364 Default is @code{row}.
4367 Set display mode for @code{waveform} and @code{levels}.
4368 It accepts the following values:
4371 Display separate graph for the color components side by side in
4372 @code{row} waveform mode or one below other in @code{column} waveform mode
4373 for @code{waveform} histogram mode. For @code{levels} histogram mode
4374 per color component graphs are placed one bellow other.
4376 This display mode in @code{waveform} histogram mode makes it easy to spot
4377 color casts in the highlights and shadows of an image, by comparing the
4378 contours of the top and the bottom of each waveform.
4379 Since whites, grays, and blacks are characterized by
4380 exactly equal amounts of red, green, and blue, neutral areas of the
4381 picture should display three waveforms of roughly equal width/height.
4382 If not, the correction is easy to make by making adjustments to level the
4386 Presents information that's identical to that in the @code{parade}, except
4387 that the graphs representing color components are superimposed directly
4390 This display mode in @code{waveform} histogram mode can make it easier to spot
4391 the relative differences or similarities in overlapping areas of the color
4392 components that are supposed to be identical, such as neutral whites, grays,
4395 Default is @code{parade}.
4398 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
4399 Default is @code{linear}.
4402 @subsection Examples
4407 Calculate and draw histogram:
4409 ffplay -i input -vf histogram
4417 High precision/quality 3d denoise filter. This filter aims to reduce
4418 image noise producing smooth images and making still images really
4419 still. It should enhance compressibility.
4421 It accepts the following optional parameters:
4425 a non-negative float number which specifies spatial luma strength,
4428 @item chroma_spatial
4429 a non-negative float number which specifies spatial chroma strength,
4430 defaults to 3.0*@var{luma_spatial}/4.0
4433 a float number which specifies luma temporal strength, defaults to
4434 6.0*@var{luma_spatial}/4.0
4437 a float number which specifies chroma temporal strength, defaults to
4438 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
4443 Modify the hue and/or the saturation of the input.
4445 This filter accepts the following options:
4449 Specify the hue angle as a number of degrees. It accepts an expression,
4450 and defaults to "0".
4453 Specify the saturation in the [-10,10] range. It accepts an expression and
4457 Specify the hue angle as a number of radians. It accepts an
4458 expression, and defaults to "0".
4461 @option{h} and @option{H} are mutually exclusive, and can't be
4462 specified at the same time.
4464 The @option{h}, @option{H} and @option{s} option values are
4465 expressions containing the following constants:
4469 frame count of the input frame starting from 0
4472 presentation timestamp of the input frame expressed in time base units
4475 frame rate of the input video, NAN if the input frame rate is unknown
4478 timestamp expressed in seconds, NAN if the input timestamp is unknown
4481 time base of the input video
4484 @subsection Examples
4488 Set the hue to 90 degrees and the saturation to 1.0:
4494 Same command but expressing the hue in radians:
4500 Rotate hue and make the saturation swing between 0
4501 and 2 over a period of 1 second:
4503 hue="H=2*PI*t: s=sin(2*PI*t)+1"
4507 Apply a 3 seconds saturation fade-in effect starting at 0:
4512 The general fade-in expression can be written as:
4514 hue="s=min(0\, max((t-START)/DURATION\, 1))"
4518 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
4520 hue="s=max(0\, min(1\, (8-t)/3))"
4523 The general fade-out expression can be written as:
4525 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
4530 @subsection Commands
4532 This filter supports the following commands:
4537 Modify the hue and/or the saturation of the input video.
4538 The command accepts the same syntax of the corresponding option.
4540 If the specified expression is not valid, it is kept at its current
4546 Detect video interlacing type.
4548 This filter tries to detect if the input is interlaced or progressive,
4549 top or bottom field first.
4551 The filter accepts the following options:
4555 Set interlacing threshold.
4557 Set progressive threshold.
4562 Deinterleave or interleave fields.
4564 This filter allows to process interlaced images fields without
4565 deinterlacing them. Deinterleaving splits the input frame into 2
4566 fields (so called half pictures). Odd lines are moved to the top
4567 half of the output image, even lines to the bottom half.
4568 You can process (filter) them independently and then re-interleave them.
4570 The filter accepts the following options:
4574 @item chroma_mode, c
4576 Available values for @var{luma_mode}, @var{chroma_mode} and
4577 @var{alpha_mode} are:
4583 @item deinterleave, d
4584 Deinterleave fields, placing one above the other.
4587 Interleave fields. Reverse the effect of deinterleaving.
4589 Default value is @code{none}.
4592 @item chroma_swap, cs
4593 @item alpha_swap, as
4594 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
4599 Simple interlacing filter from progressive contents. This interleaves upper (or
4600 lower) lines from odd frames with lower (or upper) lines from even frames,
4601 halving the frame rate and preserving image height.
4604 Original Original New Frame
4605 Frame 'j' Frame 'j+1' (tff)
4606 ========== =========== ==================
4607 Line 0 --------------------> Frame 'j' Line 0
4608 Line 1 Line 1 ----> Frame 'j+1' Line 1
4609 Line 2 ---------------------> Frame 'j' Line 2
4610 Line 3 Line 3 ----> Frame 'j+1' Line 3
4612 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
4615 It accepts the following optional parameters:
4619 determines whether the interlaced frame is taken from the even (tff - default)
4620 or odd (bff) lines of the progressive frame.
4623 Enable (default) or disable the vertical lowpass filter to avoid twitter
4624 interlacing and reduce moire patterns.
4629 Deinterlace input video by applying Donald Graft's adaptive kernel
4630 deinterling. Work on interlaced parts of a video to produce
4633 The description of the accepted parameters follows.
4637 Set the threshold which affects the filter's tolerance when
4638 determining if a pixel line must be processed. It must be an integer
4639 in the range [0,255] and defaults to 10. A value of 0 will result in
4640 applying the process on every pixels.
4643 Paint pixels exceeding the threshold value to white if set to 1.
4647 Set the fields order. Swap fields if set to 1, leave fields alone if
4651 Enable additional sharpening if set to 1. Default is 0.
4654 Enable twoway sharpening if set to 1. Default is 0.
4657 @subsection Examples
4661 Apply default values:
4663 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
4667 Enable additional sharpening:
4673 Paint processed pixels in white:
4682 Apply a 3D LUT to an input video.
4684 The filter accepts the following options:
4688 Set the 3D LUT file name.
4690 Currently supported formats:
4702 Select interpolation mode.
4704 Available values are:
4708 Use values from the nearest defined point.
4710 Interpolate values using the 8 points defining a cube.
4712 Interpolate values using a tetrahedron.
4716 @section lut, lutrgb, lutyuv
4718 Compute a look-up table for binding each pixel component input value
4719 to an output value, and apply it to input video.
4721 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
4722 to an RGB input video.
4724 These filters accept the following options:
4727 set first pixel component expression
4729 set second pixel component expression
4731 set third pixel component expression
4733 set fourth pixel component expression, corresponds to the alpha component
4736 set red component expression
4738 set green component expression
4740 set blue component expression
4742 alpha component expression
4745 set Y/luminance component expression
4747 set U/Cb component expression
4749 set V/Cr component expression
4752 Each of them specifies the expression to use for computing the lookup table for
4753 the corresponding pixel component values.
4755 The exact component associated to each of the @var{c*} options depends on the
4758 The @var{lut} filter requires either YUV or RGB pixel formats in input,
4759 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
4761 The expressions can contain the following constants and functions:
4766 the input width and height
4769 input value for the pixel component
4772 the input value clipped in the @var{minval}-@var{maxval} range
4775 maximum value for the pixel component
4778 minimum value for the pixel component
4781 the negated value for the pixel component value clipped in the
4782 @var{minval}-@var{maxval} range , it corresponds to the expression
4783 "maxval-clipval+minval"
4786 the computed value in @var{val} clipped in the
4787 @var{minval}-@var{maxval} range
4789 @item gammaval(gamma)
4790 the computed gamma correction value of the pixel component value
4791 clipped in the @var{minval}-@var{maxval} range, corresponds to the
4793 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
4797 All expressions default to "val".
4799 @subsection Examples
4805 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
4806 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
4809 The above is the same as:
4811 lutrgb="r=negval:g=negval:b=negval"
4812 lutyuv="y=negval:u=negval:v=negval"
4822 Remove chroma components, turns the video into a graytone image:
4824 lutyuv="u=128:v=128"
4828 Apply a luma burning effect:
4834 Remove green and blue components:
4840 Set a constant alpha channel value on input:
4842 format=rgba,lutrgb=a="maxval-minval/2"
4846 Correct luminance gamma by a 0.5 factor:
4848 lutyuv=y=gammaval(0.5)
4852 Discard least significant bits of luma:
4854 lutyuv=y='bitand(val, 128+64+32)'
4860 Apply motion-compensation deinterlacing.
4862 It needs one field per frame as input and must thus be used together
4863 with yadif=1/3 or equivalent.
4865 This filter accepts the following options:
4868 Set the deinterlacing mode.
4870 It accepts one of the following values:
4875 use iterative motion estimation
4877 like @samp{slow}, but use multiple reference frames.
4879 Default value is @samp{fast}.
4882 Set the picture field parity assumed for the input video. It must be
4883 one of the following values:
4887 assume top field first
4889 assume bottom field first
4892 Default value is @samp{bff}.
4895 Set per-block quantization parameter (QP) used by the internal
4898 Higher values should result in a smoother motion vector field but less
4899 optimal individual vectors. Default value is 1.
4904 Apply an MPlayer filter to the input video.
4906 This filter provides a wrapper around most of the filters of
4909 This wrapper is considered experimental. Some of the wrapped filters
4910 may not work properly and we may drop support for them, as they will
4911 be implemented natively into FFmpeg. Thus you should avoid
4912 depending on them when writing portable scripts.
4914 The filters accepts the parameters:
4915 @var{filter_name}[:=]@var{filter_params}
4917 @var{filter_name} is the name of a supported MPlayer filter,
4918 @var{filter_params} is a string containing the parameters accepted by
4921 The list of the currently supported filters follows:
4939 The parameter syntax and behavior for the listed filters are the same
4940 of the corresponding MPlayer filters. For detailed instructions check
4941 the "VIDEO FILTERS" section in the MPlayer manual.
4943 @subsection Examples
4947 Adjust gamma, brightness, contrast:
4953 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
4957 Drop frames that do not differ greatly from the previous frame in
4958 order to reduce frame rate.
4960 The main use of this filter is for very-low-bitrate encoding
4961 (e.g. streaming over dialup modem), but it could in theory be used for
4962 fixing movies that were inverse-telecined incorrectly.
4964 A description of the accepted options follows.
4968 Set the maximum number of consecutive frames which can be dropped (if
4969 positive), or the minimum interval between dropped frames (if
4970 negative). If the value is 0, the frame is dropped unregarding the
4971 number of previous sequentially dropped frames.
4978 Set the dropping threshold values.
4980 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
4981 represent actual pixel value differences, so a threshold of 64
4982 corresponds to 1 unit of difference for each pixel, or the same spread
4983 out differently over the block.
4985 A frame is a candidate for dropping if no 8x8 blocks differ by more
4986 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
4987 meaning the whole image) differ by more than a threshold of @option{lo}.
4989 Default value for @option{hi} is 64*12, default value for @option{lo} is
4990 64*5, and default value for @option{frac} is 0.33.
4998 This filter accepts an integer in input, if non-zero it negates the
4999 alpha component (if available). The default value in input is 0.
5003 Force libavfilter not to use any of the specified pixel formats for the
5004 input to the next filter.
5006 This filter accepts the following parameters:
5010 A '|'-separated list of pixel format names, for example
5011 "pix_fmts=yuv420p|monow|rgb24".
5015 @subsection Examples
5019 Force libavfilter to use a format different from @var{yuv420p} for the
5020 input to the vflip filter:
5022 noformat=pix_fmts=yuv420p,vflip
5026 Convert the input video to any of the formats not contained in the list:
5028 noformat=yuv420p|yuv444p|yuv410p
5034 Add noise on video input frame.
5036 The filter accepts the following options:
5044 Set noise seed for specific pixel component or all pixel components in case
5045 of @var{all_seed}. Default value is @code{123457}.
5047 @item all_strength, alls
5048 @item c0_strength, c0s
5049 @item c1_strength, c1s
5050 @item c2_strength, c2s
5051 @item c3_strength, c3s
5052 Set noise strength for specific pixel component or all pixel components in case
5053 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
5055 @item all_flags, allf
5060 Set pixel component flags or set flags for all components if @var{all_flags}.
5061 Available values for component flags are:
5064 averaged temporal noise (smoother)
5066 mix random noise with a (semi)regular pattern
5068 temporal noise (noise pattern changes between frames)
5070 uniform noise (gaussian otherwise)
5074 @subsection Examples
5076 Add temporal and uniform noise to input video:
5078 noise=alls=20:allf=t+u
5083 Pass the video source unchanged to the output.
5087 Apply video transform using libopencv.
5089 To enable this filter install libopencv library and headers and
5090 configure FFmpeg with @code{--enable-libopencv}.
5092 This filter accepts the following parameters:
5097 The name of the libopencv filter to apply.
5100 The parameters to pass to the libopencv filter. If not specified the default
5105 Refer to the official libopencv documentation for more precise
5107 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
5109 Follows the list of supported libopencv filters.
5114 Dilate an image by using a specific structuring element.
5115 This filter corresponds to the libopencv function @code{cvDilate}.
5117 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
5119 @var{struct_el} represents a structuring element, and has the syntax:
5120 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
5122 @var{cols} and @var{rows} represent the number of columns and rows of
5123 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
5124 point, and @var{shape} the shape for the structuring element, and
5125 can be one of the values "rect", "cross", "ellipse", "custom".
5127 If the value for @var{shape} is "custom", it must be followed by a
5128 string of the form "=@var{filename}". The file with name
5129 @var{filename} is assumed to represent a binary image, with each
5130 printable character corresponding to a bright pixel. When a custom
5131 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
5132 or columns and rows of the read file are assumed instead.
5134 The default value for @var{struct_el} is "3x3+0x0/rect".
5136 @var{nb_iterations} specifies the number of times the transform is
5137 applied to the image, and defaults to 1.
5139 Follow some example:
5141 # use the default values
5144 # dilate using a structuring element with a 5x5 cross, iterate two times
5145 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
5147 # read the shape from the file diamond.shape, iterate two times
5148 # the file diamond.shape may contain a pattern of characters like this:
5154 # the specified cols and rows are ignored (but not the anchor point coordinates)
5155 ocv=dilate:0x0+2x2/custom=diamond.shape|2
5160 Erode an image by using a specific structuring element.
5161 This filter corresponds to the libopencv function @code{cvErode}.
5163 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
5164 with the same syntax and semantics as the @ref{dilate} filter.
5168 Smooth the input video.
5170 The filter takes the following parameters:
5171 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
5173 @var{type} is the type of smooth filter to apply, and can be one of
5174 the following values: "blur", "blur_no_scale", "median", "gaussian",
5175 "bilateral". The default value is "gaussian".
5177 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
5178 parameters whose meanings depend on smooth type. @var{param1} and
5179 @var{param2} accept integer positive values or 0, @var{param3} and
5180 @var{param4} accept float values.
5182 The default value for @var{param1} is 3, the default value for the
5183 other parameters is 0.
5185 These parameters correspond to the parameters assigned to the
5186 libopencv function @code{cvSmooth}.
5191 Overlay one video on top of another.
5193 It takes two inputs and one output, the first input is the "main"
5194 video on which the second input is overlayed.
5196 This filter accepts the following parameters:
5198 A description of the accepted options follows.
5203 Set the expression for the x and y coordinates of the overlayed video
5204 on the main video. Default value is "0" for both expressions. In case
5205 the expression is invalid, it is set to a huge value (meaning that the
5206 overlay will not be displayed within the output visible area).
5209 Set when the expressions for @option{x}, and @option{y} are evaluated.
5211 It accepts the following values:
5214 only evaluate expressions once during the filter initialization or
5215 when a command is processed
5218 evaluate expressions for each incoming frame
5221 Default value is @samp{frame}.
5224 If set to 1, force the output to terminate when the shortest input
5225 terminates. Default value is 0.
5228 Set the format for the output video.
5230 It accepts the following values:
5242 Default value is @samp{yuv420}.
5244 @item rgb @emph{(deprecated)}
5245 If set to 1, force the filter to accept inputs in the RGB
5246 color space. Default value is 0. This option is deprecated, use
5247 @option{format} instead.
5250 If set to 1, force the filter to draw the last overlay frame over the
5251 main input until the end of the stream. A value of 0 disables this
5252 behavior, which is enabled by default.
5255 The @option{x}, and @option{y} expressions can contain the following
5261 main input width and height
5265 overlay input width and height
5269 the computed values for @var{x} and @var{y}. They are evaluated for
5274 horizontal and vertical chroma subsample values of the output
5275 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
5279 the number of input frame, starting from 0
5282 the position in the file of the input frame, NAN if unknown
5285 timestamp expressed in seconds, NAN if the input timestamp is unknown
5288 Note that the @var{n}, @var{pos}, @var{t} variables are available only
5289 when evaluation is done @emph{per frame}, and will evaluate to NAN
5290 when @option{eval} is set to @samp{init}.
5292 Be aware that frames are taken from each input video in timestamp
5293 order, hence, if their initial timestamps differ, it is a a good idea
5294 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
5295 have them begin in the same zero timestamp, as it does the example for
5296 the @var{movie} filter.
5298 You can chain together more overlays but you should test the
5299 efficiency of such approach.
5301 @subsection Commands
5303 This filter supports the following commands:
5307 Modify the x and y of the overlay input.
5308 The command accepts the same syntax of the corresponding option.
5310 If the specified expression is not valid, it is kept at its current
5314 @subsection Examples
5318 Draw the overlay at 10 pixels from the bottom right corner of the main
5321 overlay=main_w-overlay_w-10:main_h-overlay_h-10
5324 Using named options the example above becomes:
5326 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
5330 Insert a transparent PNG logo in the bottom left corner of the input,
5331 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
5333 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
5337 Insert 2 different transparent PNG logos (second logo on bottom
5338 right corner) using the @command{ffmpeg} tool:
5340 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
5344 Add a transparent color layer on top of the main video, @code{WxH}
5345 must specify the size of the main input to the overlay filter:
5347 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
5351 Play an original video and a filtered version (here with the deshake
5352 filter) side by side using the @command{ffplay} tool:
5354 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
5357 The above command is the same as:
5359 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
5363 Make a sliding overlay appearing from the left to the right top part of the
5364 screen starting since time 2:
5366 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
5370 Compose output by putting two input videos side to side:
5372 ffmpeg -i left.avi -i right.avi -filter_complex "
5373 nullsrc=size=200x100 [background];
5374 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
5375 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
5376 [background][left] overlay=shortest=1 [background+left];
5377 [background+left][right] overlay=shortest=1:x=100 [left+right]
5382 Chain several overlays in cascade:
5384 nullsrc=s=200x200 [bg];
5385 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
5386 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
5387 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
5388 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
5389 [in3] null, [mid2] overlay=100:100 [out0]
5396 Apply Overcomplete Wavelet denoiser.
5398 The filter accepts the following options:
5404 Larger depth values will denoise lower frequency components more, but
5405 slow down filtering.
5407 Must be an int in the range 8-16, default is @code{8}.
5409 @item luma_strength, ls
5412 Must be a double value in the range 0-1000, default is @code{1.0}.
5414 @item chroma_strength, cs
5415 Set chroma strength.
5417 Must be a double value in the range 0-1000, default is @code{1.0}.
5422 Add paddings to the input image, and place the original input at the
5423 given coordinates @var{x}, @var{y}.
5425 This filter accepts the following parameters:
5430 Specify an expression for the size of the output image with the
5431 paddings added. If the value for @var{width} or @var{height} is 0, the
5432 corresponding input size is used for the output.
5434 The @var{width} expression can reference the value set by the
5435 @var{height} expression, and vice versa.
5437 The default value of @var{width} and @var{height} is 0.
5441 Specify an expression for the offsets where to place the input image
5442 in the padded area with respect to the top/left border of the output
5445 The @var{x} expression can reference the value set by the @var{y}
5446 expression, and vice versa.
5448 The default value of @var{x} and @var{y} is 0.
5451 Specify the color of the padded area, it can be the name of a color
5452 (case insensitive match) or a 0xRRGGBB[AA] sequence.
5454 The default value of @var{color} is "black".
5457 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
5458 options are expressions containing the following constants:
5463 the input video width and height
5467 same as @var{in_w} and @var{in_h}
5471 the output width and height, that is the size of the padded area as
5472 specified by the @var{width} and @var{height} expressions
5476 same as @var{out_w} and @var{out_h}
5480 x and y offsets as specified by the @var{x} and @var{y}
5481 expressions, or NAN if not yet specified
5484 same as @var{iw} / @var{ih}
5487 input sample aspect ratio
5490 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
5494 horizontal and vertical chroma subsample values. For example for the
5495 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5498 @subsection Examples
5502 Add paddings with color "violet" to the input video. Output video
5503 size is 640x480, the top-left corner of the input video is placed at
5506 pad=640:480:0:40:violet
5509 The example above is equivalent to the following command:
5511 pad=width=640:height=480:x=0:y=40:color=violet
5515 Pad the input to get an output with dimensions increased by 3/2,
5516 and put the input video at the center of the padded area:
5518 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
5522 Pad the input to get a squared output with size equal to the maximum
5523 value between the input width and height, and put the input video at
5524 the center of the padded area:
5526 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
5530 Pad the input to get a final w/h ratio of 16:9:
5532 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
5536 In case of anamorphic video, in order to set the output display aspect
5537 correctly, it is necessary to use @var{sar} in the expression,
5538 according to the relation:
5540 (ih * X / ih) * sar = output_dar
5541 X = output_dar / sar
5544 Thus the previous example needs to be modified to:
5546 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
5550 Double output size and put the input video in the bottom-right
5551 corner of the output padded area:
5553 pad="2*iw:2*ih:ow-iw:oh-ih"
5557 @section pixdesctest
5559 Pixel format descriptor test filter, mainly useful for internal
5560 testing. The output video should be equal to the input video.
5564 format=monow, pixdesctest
5567 can be used to test the monowhite pixel format descriptor definition.
5571 Enable the specified chain of postprocessing subfilters using libpostproc. This
5572 library should be automatically selected with a GPL build (@code{--enable-gpl}).
5573 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
5574 Each subfilter and some options have a short and a long name that can be used
5575 interchangeably, i.e. dr/dering are the same.
5577 The filters accept the following options:
5581 Set postprocessing subfilters string.
5584 All subfilters share common options to determine their scope:
5588 Honor the quality commands for this subfilter.
5591 Do chrominance filtering, too (default).
5594 Do luminance filtering only (no chrominance).
5597 Do chrominance filtering only (no luminance).
5600 These options can be appended after the subfilter name, separated by a '|'.
5602 Available subfilters are:
5605 @item hb/hdeblock[|difference[|flatness]]
5606 Horizontal deblocking filter
5609 Difference factor where higher values mean more deblocking (default: @code{32}).
5611 Flatness threshold where lower values mean more deblocking (default: @code{39}).
5614 @item vb/vdeblock[|difference[|flatness]]
5615 Vertical deblocking filter
5618 Difference factor where higher values mean more deblocking (default: @code{32}).
5620 Flatness threshold where lower values mean more deblocking (default: @code{39}).
5623 @item ha/hadeblock[|difference[|flatness]]
5624 Accurate horizontal deblocking filter
5627 Difference factor where higher values mean more deblocking (default: @code{32}).
5629 Flatness threshold where lower values mean more deblocking (default: @code{39}).
5632 @item va/vadeblock[|difference[|flatness]]
5633 Accurate vertical deblocking filter
5636 Difference factor where higher values mean more deblocking (default: @code{32}).
5638 Flatness threshold where lower values mean more deblocking (default: @code{39}).
5642 The horizontal and vertical deblocking filters share the difference and
5643 flatness values so you cannot set different horizontal and vertical
5648 Experimental horizontal deblocking filter
5651 Experimental vertical deblocking filter
5656 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
5659 larger -> stronger filtering
5661 larger -> stronger filtering
5663 larger -> stronger filtering
5666 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
5669 Stretch luminance to @code{0-255}.
5672 @item lb/linblenddeint
5673 Linear blend deinterlacing filter that deinterlaces the given block by
5674 filtering all lines with a @code{(1 2 1)} filter.
5676 @item li/linipoldeint
5677 Linear interpolating deinterlacing filter that deinterlaces the given block by
5678 linearly interpolating every second line.
5680 @item ci/cubicipoldeint
5681 Cubic interpolating deinterlacing filter deinterlaces the given block by
5682 cubically interpolating every second line.
5684 @item md/mediandeint
5685 Median deinterlacing filter that deinterlaces the given block by applying a
5686 median filter to every second line.
5688 @item fd/ffmpegdeint
5689 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
5690 second line with a @code{(-1 4 2 4 -1)} filter.
5693 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
5694 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
5696 @item fq/forceQuant[|quantizer]
5697 Overrides the quantizer table from the input with the constant quantizer you
5705 Default pp filter combination (@code{hb|a,vb|a,dr|a})
5708 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
5711 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
5714 @subsection Examples
5718 Apply horizontal and vertical deblocking, deringing and automatic
5719 brightness/contrast:
5725 Apply default filters without brightness/contrast correction:
5731 Apply default filters and temporal denoiser:
5733 pp=default/tmpnoise|1|2|3
5737 Apply deblocking on luminance only, and switch vertical deblocking on or off
5738 automatically depending on available CPU time:
5746 Suppress a TV station logo, using an image file to determine which
5747 pixels comprise the logo. It works by filling in the pixels that
5748 comprise the logo with neighboring pixels.
5750 The filter accepts the following options:
5754 Set the filter bitmap file, which can be any image format supported by
5755 libavformat. The width and height of the image file must match those of the
5756 video stream being processed.
5759 Pixels in the provided bitmap image with a value of zero are not
5760 considered part of the logo, non-zero pixels are considered part of
5761 the logo. If you use white (255) for the logo and black (0) for the
5762 rest, you will be safe. For making the filter bitmap, it is
5763 recommended to take a screen capture of a black frame with the logo
5764 visible, and then using a threshold filter followed by the erode
5765 filter once or twice.
5767 If needed, little splotches can be fixed manually. Remember that if
5768 logo pixels are not covered, the filter quality will be much
5769 reduced. Marking too many pixels as part of the logo does not hurt as
5770 much, but it will increase the amount of blurring needed to cover over
5771 the image and will destroy more information than necessary, and extra
5772 pixels will slow things down on a large logo.
5776 Apply Shape Adaptive Blur.
5778 The filter accepts the following options:
5781 @item luma_radius, lr
5782 Set luma blur filter strength, must be a value in range 0.1-4.0, default
5783 value is 1.0. A greater value will result in a more blurred image, and
5784 in slower processing.
5786 @item luma_pre_filter_radius, lpfr
5787 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
5790 @item luma_strength, ls
5791 Set luma maximum difference between pixels to still be considered, must
5792 be a value in the 0.1-100.0 range, default value is 1.0.
5794 @item chroma_radius, cr
5795 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
5796 greater value will result in a more blurred image, and in slower
5799 @item chroma_pre_filter_radius, cpfr
5800 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
5802 @item chroma_strength, cs
5803 Set chroma maximum difference between pixels to still be considered,
5804 must be a value in the 0.1-100.0 range.
5807 Each chroma option value, if not explicitly specified, is set to the
5808 corresponding luma option value.
5812 Scale (resize) the input video, using the libswscale library.
5814 The scale filter forces the output display aspect ratio to be the same
5815 of the input, by changing the output sample aspect ratio.
5817 The filter accepts the following options:
5821 Set the output video width expression. Default value is @code{iw}. See
5822 below for the list of accepted constants.
5825 Set the output video height expression. Default value is @code{ih}.
5826 See below for the list of accepted constants.
5829 Set the interlacing. It accepts the following values:
5833 force interlaced aware scaling
5836 do not apply interlaced scaling
5839 select interlaced aware scaling depending on whether the source frames
5840 are flagged as interlaced or not
5843 Default value is @code{0}.
5846 Set libswscale scaling flags. If not explictly specified the filter
5847 applies a bilinear scaling algorithm.
5850 Set the video size, the value must be a valid abbreviation or in the
5851 form @var{width}x@var{height}.
5854 The values of the @var{w} and @var{h} options are expressions
5855 containing the following constants:
5860 the input width and height
5864 same as @var{in_w} and @var{in_h}
5868 the output (cropped) width and height
5872 same as @var{out_w} and @var{out_h}
5875 same as @var{iw} / @var{ih}
5878 input sample aspect ratio
5881 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
5885 horizontal and vertical chroma subsample values. For example for the
5886 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5889 If the input image format is different from the format requested by
5890 the next filter, the scale filter will convert the input to the
5893 If the value for @var{w} or @var{h} is 0, the respective input
5894 size is used for the output.
5896 If the value for @var{w} or @var{h} is -1, the scale filter will use, for the
5897 respective output size, a value that maintains the aspect ratio of the input
5900 @subsection Examples
5904 Scale the input video to a size of 200x100:
5909 This is equivalent to:
5920 Specify a size abbreviation for the output size:
5925 which can also be written as:
5931 Scale the input to 2x:
5937 The above is the same as:
5943 Scale the input to 2x with forced interlaced scaling:
5945 scale=2*iw:2*ih:interl=1
5949 Scale the input to half size:
5955 Increase the width, and set the height to the same size:
5961 Seek for Greek harmony:
5968 Increase the height, and set the width to 3/2 of the height:
5970 scale=w=3/2*oh:h=3/5*ih
5974 Increase the size, but make the size a multiple of the chroma
5977 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
5981 Increase the width to a maximum of 500 pixels, keep the same input
5984 scale=w='min(500\, iw*3/2):h=-1'
5988 @section separatefields
5990 The @code{separatefields} takes a frame-based video input and splits
5991 each frame into its components fields, producing a new half height clip
5992 with twice the frame rate and twice the frame count.
5994 This filter use field-dominance information in frame to decide which
5995 of each pair of fields to place first in the output.
5996 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
5998 @section setdar, setsar
6000 The @code{setdar} filter sets the Display Aspect Ratio for the filter
6003 This is done by changing the specified Sample (aka Pixel) Aspect
6004 Ratio, according to the following equation:
6006 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
6009 Keep in mind that the @code{setdar} filter does not modify the pixel
6010 dimensions of the video frame. Also the display aspect ratio set by
6011 this filter may be changed by later filters in the filterchain,
6012 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
6015 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
6016 the filter output video.
6018 Note that as a consequence of the application of this filter, the
6019 output display aspect ratio will change according to the equation
6022 Keep in mind that the sample aspect ratio set by the @code{setsar}
6023 filter may be changed by later filters in the filterchain, e.g. if
6024 another "setsar" or a "setdar" filter is applied.
6026 The filters accept the following options:
6029 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
6030 Set the aspect ratio used by the filter.
6032 The parameter can be a floating point number string, an expression, or
6033 a string of the form @var{num}:@var{den}, where @var{num} and
6034 @var{den} are the numerator and denominator of the aspect ratio. If
6035 the parameter is not specified, it is assumed the value "0".
6036 In case the form "@var{num}:@var{den}" is used, the @code{:} character
6040 Set the maximum integer value to use for expressing numerator and
6041 denominator when reducing the expressed aspect ratio to a rational.
6042 Default value is @code{100}.
6046 @subsection Examples
6051 To change the display aspect ratio to 16:9, specify one of the following:
6059 To change the sample aspect ratio to 10:11, specify:
6065 To set a display aspect ratio of 16:9, and specify a maximum integer value of
6066 1000 in the aspect ratio reduction, use the command:
6068 setdar=ratio=16/9:max=1000
6076 Force field for the output video frame.
6078 The @code{setfield} filter marks the interlace type field for the
6079 output frames. It does not change the input frame, but only sets the
6080 corresponding property, which affects how the frame is treated by
6081 following filters (e.g. @code{fieldorder} or @code{yadif}).
6083 The filter accepts the following options:
6088 Available values are:
6092 Keep the same field property.
6095 Mark the frame as bottom-field-first.
6098 Mark the frame as top-field-first.
6101 Mark the frame as progressive.
6107 Show a line containing various information for each input video frame.
6108 The input video is not modified.
6110 The shown line contains a sequence of key/value pairs of the form
6111 @var{key}:@var{value}.
6113 A description of each shown parameter follows:
6117 sequential number of the input frame, starting from 0
6120 Presentation TimeStamp of the input frame, expressed as a number of
6121 time base units. The time base unit depends on the filter input pad.
6124 Presentation TimeStamp of the input frame, expressed as a number of
6128 position of the frame in the input stream, -1 if this information in
6129 unavailable and/or meaningless (for example in case of synthetic video)
6135 sample aspect ratio of the input frame, expressed in the form
6139 size of the input frame, expressed in the form
6140 @var{width}x@var{height}
6143 interlaced mode ("P" for "progressive", "T" for top field first, "B"
6144 for bottom field first)
6147 1 if the frame is a key frame, 0 otherwise
6150 picture type of the input frame ("I" for an I-frame, "P" for a
6151 P-frame, "B" for a B-frame, "?" for unknown type).
6152 Check also the documentation of the @code{AVPictureType} enum and of
6153 the @code{av_get_picture_type_char} function defined in
6154 @file{libavutil/avutil.h}.
6157 Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame
6159 @item plane_checksum
6160 Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
6161 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]"
6167 Blur the input video without impacting the outlines.
6169 The filter accepts the following options:
6172 @item luma_radius, lr
6173 Set the luma radius. The option value must be a float number in
6174 the range [0.1,5.0] that specifies the variance of the gaussian filter
6175 used to blur the image (slower if larger). Default value is 1.0.
6177 @item luma_strength, ls
6178 Set the luma strength. The option value must be a float number
6179 in the range [-1.0,1.0] that configures the blurring. A value included
6180 in [0.0,1.0] will blur the image whereas a value included in
6181 [-1.0,0.0] will sharpen the image. Default value is 1.0.
6183 @item luma_threshold, lt
6184 Set the luma threshold used as a coefficient to determine
6185 whether a pixel should be blurred or not. The option value must be an
6186 integer in the range [-30,30]. A value of 0 will filter all the image,
6187 a value included in [0,30] will filter flat areas and a value included
6188 in [-30,0] will filter edges. Default value is 0.
6190 @item chroma_radius, cr
6191 Set the chroma radius. The option value must be a float number in
6192 the range [0.1,5.0] that specifies the variance of the gaussian filter
6193 used to blur the image (slower if larger). Default value is 1.0.
6195 @item chroma_strength, cs
6196 Set the chroma strength. The option value must be a float number
6197 in the range [-1.0,1.0] that configures the blurring. A value included
6198 in [0.0,1.0] will blur the image whereas a value included in
6199 [-1.0,0.0] will sharpen the image. Default value is 1.0.
6201 @item chroma_threshold, ct
6202 Set the chroma threshold used as a coefficient to determine
6203 whether a pixel should be blurred or not. The option value must be an
6204 integer in the range [-30,30]. A value of 0 will filter all the image,
6205 a value included in [0,30] will filter flat areas and a value included
6206 in [-30,0] will filter edges. Default value is 0.
6209 If a chroma option is not explicitly set, the corresponding luma value
6214 Convert between different stereoscopic image formats.
6216 The filters accept the following options:
6220 Set stereoscopic image format of input.
6222 Available values for input image formats are:
6225 side by side parallel (left eye left, right eye right)
6228 side by side crosseye (right eye left, left eye right)
6231 side by side parallel with half width resolution
6232 (left eye left, right eye right)
6235 side by side crosseye with half width resolution
6236 (right eye left, left eye right)
6239 above-below (left eye above, right eye below)
6242 above-below (right eye above, left eye below)
6245 above-below with half height resolution
6246 (left eye above, right eye below)
6249 above-below with half height resolution
6250 (right eye above, left eye below)
6253 alternating frames (left eye first, right eye second)
6256 alternating frames (right eye first, left eye second)
6258 Default value is @samp{sbsl}.
6262 Set stereoscopic image format of output.
6264 Available values for output image formats are all the input formats as well as:
6267 anaglyph red/blue gray
6268 (red filter on left eye, blue filter on right eye)
6271 anaglyph red/green gray
6272 (red filter on left eye, green filter on right eye)
6275 anaglyph red/cyan gray
6276 (red filter on left eye, cyan filter on right eye)
6279 anaglyph red/cyan half colored
6280 (red filter on left eye, cyan filter on right eye)
6283 anaglyph red/cyan color
6284 (red filter on left eye, cyan filter on right eye)
6287 anaglyph red/cyan color optimized with the least squares projection of dubois
6288 (red filter on left eye, cyan filter on right eye)
6291 anaglyph green/magenta gray
6292 (green filter on left eye, magenta filter on right eye)
6295 anaglyph green/magenta half colored
6296 (green filter on left eye, magenta filter on right eye)
6299 anaglyph green/magenta colored
6300 (green filter on left eye, magenta filter on right eye)
6303 anaglyph green/magenta color optimized with the least squares projection of dubois
6304 (green filter on left eye, magenta filter on right eye)
6307 anaglyph yellow/blue gray
6308 (yellow filter on left eye, blue filter on right eye)
6311 anaglyph yellow/blue half colored
6312 (yellow filter on left eye, blue filter on right eye)
6315 anaglyph yellow/blue colored
6316 (yellow filter on left eye, blue filter on right eye)
6319 anaglyph yellow/blue color optimized with the least squares projection of dubois
6320 (yellow filter on left eye, blue filter on right eye)
6323 interleaved rows (left eye has top row, right eye starts on next row)
6326 interleaved rows (right eye has top row, left eye starts on next row)
6329 mono output (left eye only)
6332 mono output (right eye only)
6335 Default value is @samp{arcd}.
6338 @subsection Examples
6342 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
6348 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
6357 Draw subtitles on top of input video using the libass library.
6359 To enable compilation of this filter you need to configure FFmpeg with
6360 @code{--enable-libass}. This filter also requires a build with libavcodec and
6361 libavformat to convert the passed subtitles file to ASS (Advanced Substation
6362 Alpha) subtitles format.
6364 The filter accepts the following options:
6368 Set the filename of the subtitle file to read. It must be specified.
6371 Specify the size of the original video, the video for which the ASS file
6372 was composed. Due to a misdesign in ASS aspect ratio arithmetic, this is
6373 necessary to correctly scale the fonts if the aspect ratio has been changed.
6376 Set subtitles input character encoding. @code{subtitles} filter only. Only
6377 useful if not UTF-8.
6380 If the first key is not specified, it is assumed that the first value
6381 specifies the @option{filename}.
6383 For example, to render the file @file{sub.srt} on top of the input
6384 video, use the command:
6389 which is equivalent to:
6391 subtitles=filename=sub.srt
6396 Scale the input by 2x and smooth using the Super2xSaI (Scale and
6397 Interpolate) pixel art scaling algorithm.
6399 Useful for enlarging pixel art images without reducing sharpness.
6406 Apply telecine process to the video.
6408 This filter accepts the following options:
6417 The default value is @code{top}.
6421 A string of numbers representing the pulldown pattern you wish to apply.
6422 The default value is @code{23}.
6426 Some typical patterns:
6431 24p: 2332 (preferred)
6438 24p: 222222222223 ("Euro pulldown")
6444 Select the most representative frame in a given sequence of consecutive frames.
6446 The filter accepts the following options:
6450 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
6451 will pick one of them, and then handle the next batch of @var{n} frames until
6452 the end. Default is @code{100}.
6455 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
6456 value will result in a higher memory usage, so a high value is not recommended.
6458 @subsection Examples
6462 Extract one picture each 50 frames:
6468 Complete example of a thumbnail creation with @command{ffmpeg}:
6470 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
6476 Tile several successive frames together.
6478 The filter accepts the following options:
6483 Set the grid size (i.e. the number of lines and columns) in the form
6487 Set the maximum number of frames to render in the given area. It must be less
6488 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
6489 the area will be used.
6492 Set the outer border margin in pixels.
6495 Set the inner border thickness (i.e. the number of pixels between frames). For
6496 more advanced padding options (such as having different values for the edges),
6497 refer to the pad video filter.
6501 @subsection Examples
6505 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
6507 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
6509 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
6510 duplicating each output frame to accomodate the originally detected frame
6514 Display @code{5} pictures in an area of @code{3x2} frames,
6515 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
6516 mixed flat and named options:
6518 tile=3x2:nb_frames=5:padding=7:margin=2
6524 Perform various types of temporal field interlacing.
6526 Frames are counted starting from 1, so the first input frame is
6529 The filter accepts the following options:
6534 Specify the mode of the interlacing. This option can also be specified
6535 as a value alone. See below for a list of values for this option.
6537 Available values are:
6541 Move odd frames into the upper field, even into the lower field,
6542 generating a double height frame at half frame rate.
6545 Only output even frames, odd frames are dropped, generating a frame with
6546 unchanged height at half frame rate.
6549 Only output odd frames, even frames are dropped, generating a frame with
6550 unchanged height at half frame rate.
6553 Expand each frame to full height, but pad alternate lines with black,
6554 generating a frame with double height at the same input frame rate.
6556 @item interleave_top, 4
6557 Interleave the upper field from odd frames with the lower field from
6558 even frames, generating a frame with unchanged height at half frame rate.
6560 @item interleave_bottom, 5
6561 Interleave the lower field from odd frames with the upper field from
6562 even frames, generating a frame with unchanged height at half frame rate.
6564 @item interlacex2, 6
6565 Double frame rate with unchanged height. Frames are inserted each
6566 containing the second temporal field from the previous input frame and
6567 the first temporal field from the next input frame. This mode relies on
6568 the top_field_first flag. Useful for interlaced video displays with no
6569 field synchronisation.
6572 Numeric values are deprecated but are accepted for backward
6573 compatibility reasons.
6575 Default mode is @code{merge}.
6578 Specify flags influencing the filter process.
6580 Available value for @var{flags} is:
6583 @item low_pass_filter, vlfp
6584 Enable vertical low-pass filtering in the filter.
6585 Vertical low-pass filtering is required when creating an interlaced
6586 destination from a progressive source which contains high-frequency
6587 vertical detail. Filtering will reduce interlace 'twitter' and Moire
6590 Vertical low-pass filtering can only be enabled for @option{mode}
6591 @var{interleave_top} and @var{interleave_bottom}.
6598 Transpose rows with columns in the input video and optionally flip it.
6600 This filter accepts the following options:
6605 Specify the transposition direction.
6607 Can assume the following values:
6609 @item 0, 4, cclock_flip
6610 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
6618 Rotate by 90 degrees clockwise, that is:
6626 Rotate by 90 degrees counterclockwise, that is:
6633 @item 3, 7, clock_flip
6634 Rotate by 90 degrees clockwise and vertically flip, that is:
6642 For values between 4-7, the transposition is only done if the input
6643 video geometry is portrait and not landscape. These values are
6644 deprecated, the @code{passthrough} option should be used instead.
6646 Numerical values are deprecated, and should be dropped in favor of
6650 Do not apply the transposition if the input geometry matches the one
6651 specified by the specified value. It accepts the following values:
6654 Always apply transposition.
6656 Preserve portrait geometry (when @var{height} >= @var{width}).
6658 Preserve landscape geometry (when @var{width} >= @var{height}).
6661 Default value is @code{none}.
6664 For example to rotate by 90 degrees clockwise and preserve portrait
6667 transpose=dir=1:passthrough=portrait
6670 The command above can also be specified as:
6672 transpose=1:portrait
6676 Trim the input so that the output contains one continuous subpart of the input.
6678 This filter accepts the following options:
6681 Timestamp (in seconds) of the start of the kept section. I.e. the frame with the
6682 timestamp @var{start} will be the first frame in the output.
6685 Timestamp (in seconds) of the first frame that will be dropped. I.e. the frame
6686 immediately preceding the one with the timestamp @var{end} will be the last
6687 frame in the output.
6690 Same as @var{start}, except this option sets the start timestamp in timebase
6691 units instead of seconds.
6694 Same as @var{end}, except this option sets the end timestamp in timebase units
6698 Maximum duration of the output in seconds.
6701 Number of the first frame that should be passed to output.
6704 Number of the first frame that should be dropped.
6707 Note that the first two sets of the start/end options and the @option{duration}
6708 option look at the frame timestamp, while the _frame variants simply count the
6709 frames that pass through the filter. Also note that this filter does not modify
6710 the timestamps. If you wish that the output timestamps start at zero, insert a
6711 setpts filter after the trim filter.
6713 If multiple start or end options are set, this filter tries to be greedy and
6714 keep all the frames that match at least one of the specified constraints. To keep
6715 only the part that matches all the constraints at once, chain multiple trim
6718 The defaults are such that all the input is kept. So it is possible to set e.g.
6719 just the end values to keep everything before the specified time.
6724 drop everything except the second minute of input
6726 ffmpeg -i INPUT -vf trim=60:120
6730 keep only the first second
6732 ffmpeg -i INPUT -vf trim=duration=1
6740 Sharpen or blur the input video.
6742 It accepts the following parameters:
6745 @item luma_msize_x, lx
6746 Set the luma matrix horizontal size. It must be an odd integer between
6747 3 and 63, default value is 5.
6749 @item luma_msize_y, ly
6750 Set the luma matrix vertical size. It must be an odd integer between 3
6751 and 63, default value is 5.
6753 @item luma_amount, la
6754 Set the luma effect strength. It can be a float number, reasonable
6755 values lay between -1.5 and 1.5.
6757 Negative values will blur the input video, while positive values will
6758 sharpen it, a value of zero will disable the effect.
6760 Default value is 1.0.
6762 @item chroma_msize_x, cx
6763 Set the chroma matrix horizontal size. It must be an odd integer
6764 between 3 and 63, default value is 5.
6766 @item chroma_msize_y, cy
6767 Set the chroma matrix vertical size. It must be an odd integer
6768 between 3 and 63, default value is 5.
6770 @item chroma_amount, ca
6771 Set the chroma effect strength. It can be a float number, reasonable
6772 values lay between -1.5 and 1.5.
6774 Negative values will blur the input video, while positive values will
6775 sharpen it, a value of zero will disable the effect.
6777 Default value is 0.0.
6780 If set to 1, specify using OpenCL capabilities, only available if
6781 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
6785 All parameters are optional and default to the equivalent of the
6786 string '5:5:1.0:5:5:0.0'.
6788 @subsection Examples
6792 Apply strong luma sharpen effect:
6794 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
6798 Apply strong blur of both luma and chroma parameters:
6800 unsharp=7:7:-2:7:7:-2
6804 @anchor{vidstabdetect}
6805 @section vidstabdetect
6807 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
6808 @ref{vidstabtransform} for pass 2.
6810 This filter generates a file with relative translation and rotation
6811 transform information about subsequent frames, which is then used by
6812 the @ref{vidstabtransform} filter.
6814 To enable compilation of this filter you need to configure FFmpeg with
6815 @code{--enable-libvidstab}.
6817 This filter accepts the following options:
6821 Set the path to the file used to write the transforms information.
6822 Default value is @file{transforms.trf}.
6825 Set how shaky the video is and how quick the camera is. It accepts an
6826 integer in the range 1-10, a value of 1 means little shakiness, a
6827 value of 10 means strong shakiness. Default value is 5.
6830 Set the accuracy of the detection process. It must be a value in the
6831 range 1-15. A value of 1 means low accuracy, a value of 15 means high
6832 accuracy. Default value is 9.
6835 Set stepsize of the search process. The region around minimum is
6836 scanned with 1 pixel resolution. Default value is 6.
6839 Set minimum contrast. Below this value a local measurement field is
6840 discarded. Must be a floating point value in the range 0-1. Default
6844 Set reference frame number for tripod mode.
6846 If enabled, the motion of the frames is compared to a reference frame
6847 in the filtered stream, identified by the specified number. The idea
6848 is to compensate all movements in a more-or-less static scene and keep
6849 the camera view absolutely still.
6851 If set to 0, it is disabled. The frames are counted starting from 1.
6854 Show fields and transforms in the resulting frames. It accepts an
6855 integer in the range 0-2. Default value is 0, which disables any
6859 @subsection Examples
6869 Analyze strongly shaky movie and put the results in file
6870 @file{mytransforms.trf}:
6872 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
6876 Visualize the result of internal transformations in the resulting
6879 vidstabdetect=show=1
6883 Analyze a video with medium shakiness using @command{ffmpeg}:
6885 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
6889 @anchor{vidstabtransform}
6890 @section vidstabtransform
6892 Video stabilization/deshaking: pass 2 of 2,
6893 see @ref{vidstabdetect} for pass 1.
6895 Read a file with transform information for each frame and
6896 apply/compensate them. Together with the @ref{vidstabdetect}
6897 filter this can be used to deshake videos. See also
6898 @url{http://public.hronopik.de/vid.stab}. It is important to also use
6899 the unsharp filter, see below.
6901 To enable compilation of this filter you need to configure FFmpeg with
6902 @code{--enable-libvidstab}.
6904 This filter accepts the following options:
6909 path to the file used to read the transforms (default: @file{transforms.trf})
6912 number of frames (value*2 + 1) used for lowpass filtering the camera movements
6913 (default: 10). For example a number of 10 means that 21 frames are used
6914 (10 in the past and 10 in the future) to smoothen the motion in the
6915 video. A larger values leads to a smoother video, but limits the
6916 acceleration of the camera (pan/tilt movements).
6919 maximal number of pixels to translate frames (default: -1 no limit)
6922 maximal angle in radians (degree*PI/180) to rotate frames (default: -1
6926 How to deal with borders that may be visible due to movement
6927 compensation. Available values are:
6931 keep image information from previous frame (default)
6933 fill the border black
6939 keep transforms normal (default)
6946 consider transforms as
6951 relative to previous frame (default)
6956 percentage to zoom (default: 0)
6965 if 1 then optimal zoom value is determined (default).
6966 Optimal zoom means no (or only little) border should be visible.
6967 Note that the value given at zoom is added to the one calculated
6971 type of interpolation
6973 Available values are:
6978 linear only horizontal
6980 linear in both directions (default)
6982 cubic in both directions (slow)
6986 virtual tripod mode means that the video is stabilized such that the
6987 camera stays stationary. Use also @code{tripod} option of
6988 @ref{vidstabdetect}.
6993 virtual tripod mode: equivalent to @code{relative=0:smoothing=0}
6998 @subsection Examples
7002 typical call with default default values:
7003 (note the unsharp filter which is always recommended)
7005 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
7009 zoom in a bit more and load transform data from a given file
7011 vidstabtransform=zoom=5:input="mytransforms.trf"
7015 smoothen the video even more
7017 vidstabtransform=smoothing=30
7024 Flip the input video vertically.
7026 For example, to vertically flip a video with @command{ffmpeg}:
7028 ffmpeg -i in.avi -vf "vflip" out.avi
7033 Make or reverse a natural vignetting effect.
7035 The filter accepts the following options:
7039 Set lens angle expression as a number of radians.
7041 The value is clipped in the @code{[0,PI/2]} range.
7043 Default value: @code{"PI/5"}
7047 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
7051 Set forward/backward mode.
7053 Available modes are:
7056 The larger the distance from the central point, the darker the image becomes.
7059 The larger the distance from the central point, the brighter the image becomes.
7060 This can be used to reverse a vignette effect, though there is no automatic
7061 detection to extract the lens @option{angle} and other settings (yet). It can
7062 also be used to create a burning effect.
7065 Default value is @samp{forward}.
7068 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
7070 It accepts the following values:
7073 Evaluate expressions only once during the filter initialization.
7076 Evaluate expressions for each incoming frame. This is way slower than the
7077 @samp{init} mode since it requires all the scalers to be re-computed, but it
7078 allows advanced dynamic expressions.
7081 Default value is @samp{init}.
7084 Set dithering to reduce the circular banding effects. Default is @code{1}
7088 Set vignette aspect. This setting allows to adjust the shape of the vignette.
7089 Setting this value to the SAR of the input will make a rectangular vignetting
7090 following the dimensions of the video.
7092 Default is @code{1/1}.
7095 @subsection Expressions
7097 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
7098 following parameters.
7103 input width and height
7106 the number of input frame, starting from 0
7109 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
7110 @var{TB} units, NAN if undefined
7113 frame rate of the input video, NAN if the input frame rate is unknown
7116 the PTS (Presentation TimeStamp) of the filtered video frame,
7117 expressed in seconds, NAN if undefined
7120 time base of the input video
7124 @subsection Examples
7128 Apply simple strong vignetting effect:
7134 Make a flickering vignetting:
7136 vignette='PI/4+random(1)*PI/50':eval=frame
7144 Deinterlace the input video ("yadif" means "yet another deinterlacing
7147 This filter accepts the following options:
7153 The interlacing mode to adopt, accepts one of the following values:
7157 output 1 frame for each frame
7159 output 1 frame for each field
7160 @item 2, send_frame_nospatial
7161 like @code{send_frame} but skip spatial interlacing check
7162 @item 3, send_field_nospatial
7163 like @code{send_field} but skip spatial interlacing check
7166 Default value is @code{send_frame}.
7169 The picture field parity assumed for the input interlaced video, accepts one of
7170 the following values:
7174 assume top field first
7176 assume bottom field first
7178 enable automatic detection
7181 Default value is @code{auto}.
7182 If interlacing is unknown or decoder does not export this information,
7183 top field first will be assumed.
7186 Specify which frames to deinterlace. Accept one of the following
7191 deinterlace all frames
7193 only deinterlace frames marked as interlaced
7196 Default value is @code{all}.
7199 @c man end VIDEO FILTERS
7201 @chapter Video Sources
7202 @c man begin VIDEO SOURCES
7204 Below is a description of the currently available video sources.
7208 Buffer video frames, and make them available to the filter chain.
7210 This source is mainly intended for a programmatic use, in particular
7211 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
7213 This source accepts the following options:
7218 Specify the size (width and height) of the buffered video frames.
7227 A string representing the pixel format of the buffered video frames.
7228 It may be a number corresponding to a pixel format, or a pixel format
7232 Specify the timebase assumed by the timestamps of the buffered frames.
7235 Specify the frame rate expected for the video stream.
7237 @item pixel_aspect, sar
7238 Specify the sample aspect ratio assumed by the video frames.
7241 Specify the optional parameters to be used for the scale filter which
7242 is automatically inserted when an input change is detected in the
7243 input size or format.
7248 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
7251 will instruct the source to accept video frames with size 320x240 and
7252 with format "yuv410p", assuming 1/24 as the timestamps timebase and
7253 square pixels (1:1 sample aspect ratio).
7254 Since the pixel format with name "yuv410p" corresponds to the number 6
7255 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
7256 this example corresponds to:
7258 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
7261 Alternatively, the options can be specified as a flat string, but this
7262 syntax is deprecated:
7264 @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}]
7268 Create a pattern generated by an elementary cellular automaton.
7270 The initial state of the cellular automaton can be defined through the
7271 @option{filename}, and @option{pattern} options. If such options are
7272 not specified an initial state is created randomly.
7274 At each new frame a new row in the video is filled with the result of
7275 the cellular automaton next generation. The behavior when the whole
7276 frame is filled is defined by the @option{scroll} option.
7278 This source accepts the following options:
7282 Read the initial cellular automaton state, i.e. the starting row, from
7284 In the file, each non-whitespace character is considered an alive
7285 cell, a newline will terminate the row, and further characters in the
7286 file will be ignored.
7289 Read the initial cellular automaton state, i.e. the starting row, from
7290 the specified string.
7292 Each non-whitespace character in the string is considered an alive
7293 cell, a newline will terminate the row, and further characters in the
7294 string will be ignored.
7297 Set the video rate, that is the number of frames generated per second.
7300 @item random_fill_ratio, ratio
7301 Set the random fill ratio for the initial cellular automaton row. It
7302 is a floating point number value ranging from 0 to 1, defaults to
7305 This option is ignored when a file or a pattern is specified.
7307 @item random_seed, seed
7308 Set the seed for filling randomly the initial row, must be an integer
7309 included between 0 and UINT32_MAX. If not specified, or if explicitly
7310 set to -1, the filter will try to use a good random seed on a best
7314 Set the cellular automaton rule, it is a number ranging from 0 to 255.
7315 Default value is 110.
7318 Set the size of the output video.
7320 If @option{filename} or @option{pattern} is specified, the size is set
7321 by default to the width of the specified initial state row, and the
7322 height is set to @var{width} * PHI.
7324 If @option{size} is set, it must contain the width of the specified
7325 pattern string, and the specified pattern will be centered in the
7328 If a filename or a pattern string is not specified, the size value
7329 defaults to "320x518" (used for a randomly generated initial state).
7332 If set to 1, scroll the output upward when all the rows in the output
7333 have been already filled. If set to 0, the new generated row will be
7334 written over the top row just after the bottom row is filled.
7337 @item start_full, full
7338 If set to 1, completely fill the output with generated rows before
7339 outputting the first frame.
7340 This is the default behavior, for disabling set the value to 0.
7343 If set to 1, stitch the left and right row edges together.
7344 This is the default behavior, for disabling set the value to 0.
7347 @subsection Examples
7351 Read the initial state from @file{pattern}, and specify an output of
7354 cellauto=f=pattern:s=200x400
7358 Generate a random initial row with a width of 200 cells, with a fill
7361 cellauto=ratio=2/3:s=200x200
7365 Create a pattern generated by rule 18 starting by a single alive cell
7366 centered on an initial row with width 100:
7368 cellauto=p=@@:s=100x400:full=0:rule=18
7372 Specify a more elaborated initial pattern:
7374 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
7381 Generate a Mandelbrot set fractal, and progressively zoom towards the
7382 point specified with @var{start_x} and @var{start_y}.
7384 This source accepts the following options:
7389 Set the terminal pts value. Default value is 400.
7392 Set the terminal scale value.
7393 Must be a floating point value. Default value is 0.3.
7396 Set the inner coloring mode, that is the algorithm used to draw the
7397 Mandelbrot fractal internal region.
7399 It shall assume one of the following values:
7404 Show time until convergence.
7406 Set color based on point closest to the origin of the iterations.
7411 Default value is @var{mincol}.
7414 Set the bailout value. Default value is 10.0.
7417 Set the maximum of iterations performed by the rendering
7418 algorithm. Default value is 7189.
7421 Set outer coloring mode.
7422 It shall assume one of following values:
7424 @item iteration_count
7425 Set iteration cound mode.
7426 @item normalized_iteration_count
7427 set normalized iteration count mode.
7429 Default value is @var{normalized_iteration_count}.
7432 Set frame rate, expressed as number of frames per second. Default
7436 Set frame size. Default value is "640x480".
7439 Set the initial scale value. Default value is 3.0.
7442 Set the initial x position. Must be a floating point value between
7443 -100 and 100. Default value is -0.743643887037158704752191506114774.
7446 Set the initial y position. Must be a floating point value between
7447 -100 and 100. Default value is -0.131825904205311970493132056385139.
7452 Generate various test patterns, as generated by the MPlayer test filter.
7454 The size of the generated video is fixed, and is 256x256.
7455 This source is useful in particular for testing encoding features.
7457 This source accepts the following options:
7462 Specify the frame rate of the sourced video, as the number of frames
7463 generated per second. It has to be a string in the format
7464 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
7465 number or a valid video frame rate abbreviation. The default value is
7469 Set the video duration of the sourced video. The accepted syntax is:
7474 See also the function @code{av_parse_time()}.
7476 If not specified, or the expressed duration is negative, the video is
7477 supposed to be generated forever.
7481 Set the number or the name of the test to perform. Supported tests are:
7496 Default value is "all", which will cycle through the list of all tests.
7499 For example the following:
7504 will generate a "dc_luma" test pattern.
7508 Provide a frei0r source.
7510 To enable compilation of this filter you need to install the frei0r
7511 header and configure FFmpeg with @code{--enable-frei0r}.
7513 This source accepts the following options:
7518 The size of the video to generate, may be a string of the form
7519 @var{width}x@var{height} or a frame size abbreviation.
7522 Framerate of the generated video, may be a string of the form
7523 @var{num}/@var{den} or a frame rate abbreviation.
7526 The name to the frei0r source to load. For more information regarding frei0r and
7527 how to set the parameters read the section @ref{frei0r} in the description of
7531 A '|'-separated list of parameters to pass to the frei0r source.
7535 For example, to generate a frei0r partik0l source with size 200x200
7536 and frame rate 10 which is overlayed on the overlay filter main input:
7538 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
7543 Generate a life pattern.
7545 This source is based on a generalization of John Conway's life game.
7547 The sourced input represents a life grid, each pixel represents a cell
7548 which can be in one of two possible states, alive or dead. Every cell
7549 interacts with its eight neighbours, which are the cells that are
7550 horizontally, vertically, or diagonally adjacent.
7552 At each interaction the grid evolves according to the adopted rule,
7553 which specifies the number of neighbor alive cells which will make a
7554 cell stay alive or born. The @option{rule} option allows to specify
7557 This source accepts the following options:
7561 Set the file from which to read the initial grid state. In the file,
7562 each non-whitespace character is considered an alive cell, and newline
7563 is used to delimit the end of each row.
7565 If this option is not specified, the initial grid is generated
7569 Set the video rate, that is the number of frames generated per second.
7572 @item random_fill_ratio, ratio
7573 Set the random fill ratio for the initial random grid. It is a
7574 floating point number value ranging from 0 to 1, defaults to 1/PHI.
7575 It is ignored when a file is specified.
7577 @item random_seed, seed
7578 Set the seed for filling the initial random grid, must be an integer
7579 included between 0 and UINT32_MAX. If not specified, or if explicitly
7580 set to -1, the filter will try to use a good random seed on a best
7586 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
7587 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
7588 @var{NS} specifies the number of alive neighbor cells which make a
7589 live cell stay alive, and @var{NB} the number of alive neighbor cells
7590 which make a dead cell to become alive (i.e. to "born").
7591 "s" and "b" can be used in place of "S" and "B", respectively.
7593 Alternatively a rule can be specified by an 18-bits integer. The 9
7594 high order bits are used to encode the next cell state if it is alive
7595 for each number of neighbor alive cells, the low order bits specify
7596 the rule for "borning" new cells. Higher order bits encode for an
7597 higher number of neighbor cells.
7598 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
7599 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
7601 Default value is "S23/B3", which is the original Conway's game of life
7602 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
7603 cells, and will born a new cell if there are three alive cells around
7607 Set the size of the output video.
7609 If @option{filename} is specified, the size is set by default to the
7610 same size of the input file. If @option{size} is set, it must contain
7611 the size specified in the input file, and the initial grid defined in
7612 that file is centered in the larger resulting area.
7614 If a filename is not specified, the size value defaults to "320x240"
7615 (used for a randomly generated initial grid).
7618 If set to 1, stitch the left and right grid edges together, and the
7619 top and bottom edges also. Defaults to 1.
7622 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
7623 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
7624 value from 0 to 255.
7627 Set the color of living (or new born) cells.
7630 Set the color of dead cells. If @option{mold} is set, this is the first color
7631 used to represent a dead cell.
7634 Set mold color, for definitely dead and moldy cells.
7637 @subsection Examples
7641 Read a grid from @file{pattern}, and center it on a grid of size
7644 life=f=pattern:s=300x300
7648 Generate a random grid of size 200x200, with a fill ratio of 2/3:
7650 life=ratio=2/3:s=200x200
7654 Specify a custom rule for evolving a randomly generated grid:
7660 Full example with slow death effect (mold) using @command{ffplay}:
7662 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
7667 @anchor{haldclutsrc}
7671 @anchor{smptehdbars}
7673 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
7675 The @code{color} source provides an uniformly colored input.
7677 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
7678 @ref{haldclut} filter.
7680 The @code{nullsrc} source returns unprocessed video frames. It is
7681 mainly useful to be employed in analysis / debugging tools, or as the
7682 source for filters which ignore the input data.
7684 The @code{rgbtestsrc} source generates an RGB test pattern useful for
7685 detecting RGB vs BGR issues. You should see a red, green and blue
7686 stripe from top to bottom.
7688 The @code{smptebars} source generates a color bars pattern, based on
7689 the SMPTE Engineering Guideline EG 1-1990.
7691 The @code{smptehdbars} source generates a color bars pattern, based on
7692 the SMPTE RP 219-2002.
7694 The @code{testsrc} source generates a test video pattern, showing a
7695 color pattern, a scrolling gradient and a timestamp. This is mainly
7696 intended for testing purposes.
7698 The sources accept the following options:
7703 Specify the color of the source, only available in the @code{color}
7704 source. It can be the name of a color (case insensitive match) or a
7705 0xRRGGBB[AA] sequence, possibly followed by an alpha specifier. The
7706 default value is "black".
7709 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
7710 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
7711 pixels to be used as identity matrix for 3D lookup tables. Each component is
7712 coded on a @code{1/(N*N)} scale.
7715 Specify the size of the sourced video, it may be a string of the form
7716 @var{width}x@var{height}, or the name of a size abbreviation. The
7717 default value is "320x240".
7719 This option is not available with the @code{haldclutsrc} filter.
7722 Specify the frame rate of the sourced video, as the number of frames
7723 generated per second. It has to be a string in the format
7724 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
7725 number or a valid video frame rate abbreviation. The default value is
7729 Set the sample aspect ratio of the sourced video.
7732 Set the video duration of the sourced video. The accepted syntax is:
7734 [-]HH[:MM[:SS[.m...]]]
7737 See also the function @code{av_parse_time()}.
7739 If not specified, or the expressed duration is negative, the video is
7740 supposed to be generated forever.
7743 Set the number of decimals to show in the timestamp, only available in the
7744 @code{testsrc} source.
7746 The displayed timestamp value will correspond to the original
7747 timestamp value multiplied by the power of 10 of the specified
7748 value. Default value is 0.
7751 For example the following:
7753 testsrc=duration=5.3:size=qcif:rate=10
7756 will generate a video with a duration of 5.3 seconds, with size
7757 176x144 and a frame rate of 10 frames per second.
7759 The following graph description will generate a red source
7760 with an opacity of 0.2, with size "qcif" and a frame rate of 10
7763 color=c=red@@0.2:s=qcif:r=10
7766 If the input content is to be ignored, @code{nullsrc} can be used. The
7767 following command generates noise in the luminance plane by employing
7768 the @code{geq} filter:
7770 nullsrc=s=256x256, geq=random(1)*255:128:128
7773 @subsection Commands
7775 The @code{color} source supports the following commands:
7779 Set the color of the created image. Accepts the same syntax of the
7780 corresponding @option{color} option.
7783 @c man end VIDEO SOURCES
7785 @chapter Video Sinks
7786 @c man begin VIDEO SINKS
7788 Below is a description of the currently available video sinks.
7792 Buffer video frames, and make them available to the end of the filter
7795 This sink is mainly intended for a programmatic use, in particular
7796 through the interface defined in @file{libavfilter/buffersink.h}
7797 or the options system.
7799 It accepts a pointer to an AVBufferSinkContext structure, which
7800 defines the incoming buffers' formats, to be passed as the opaque
7801 parameter to @code{avfilter_init_filter} for initialization.
7805 Null video sink, do absolutely nothing with the input video. It is
7806 mainly useful as a template and to be employed in analysis / debugging
7809 @c man end VIDEO SINKS
7811 @chapter Multimedia Filters
7812 @c man begin MULTIMEDIA FILTERS
7814 Below is a description of the currently available multimedia filters.
7816 @section avectorscope
7818 Convert input audio to a video output, representing the audio vector
7821 The filter is used to measure the difference between channels of stereo
7822 audio stream. A monoaural signal, consisting of identical left and right
7823 signal, results in straight vertical line. Any stereo separation is visible
7824 as a deviation from this line, creating a Lissajous figure.
7825 If the straight (or deviation from it) but horizontal line appears this
7826 indicates that the left and right channels are out of phase.
7828 The filter accepts the following options:
7832 Set the vectorscope mode.
7834 Available values are:
7837 Lissajous rotated by 45 degrees.
7840 Same as above but not rotated.
7843 Default value is @samp{lissajous}.
7846 Set the video size for the output. Default value is @code{400x400}.
7849 Set the output frame rate. Default value is @code{25}.
7854 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
7855 Allowed range is @code{[0, 255]}.
7860 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
7861 Allowed range is @code{[0, 255]}.
7864 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
7867 @subsection Examples
7871 Complete example using @command{ffplay}:
7873 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
7874 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
7880 Concatenate audio and video streams, joining them together one after the
7883 The filter works on segments of synchronized video and audio streams. All
7884 segments must have the same number of streams of each type, and that will
7885 also be the number of streams at output.
7887 The filter accepts the following options:
7892 Set the number of segments. Default is 2.
7895 Set the number of output video streams, that is also the number of video
7896 streams in each segment. Default is 1.
7899 Set the number of output audio streams, that is also the number of video
7900 streams in each segment. Default is 0.
7903 Activate unsafe mode: do not fail if segments have a different format.
7907 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
7908 @var{a} audio outputs.
7910 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
7911 segment, in the same order as the outputs, then the inputs for the second
7914 Related streams do not always have exactly the same duration, for various
7915 reasons including codec frame size or sloppy authoring. For that reason,
7916 related synchronized streams (e.g. a video and its audio track) should be
7917 concatenated at once. The concat filter will use the duration of the longest
7918 stream in each segment (except the last one), and if necessary pad shorter
7919 audio streams with silence.
7921 For this filter to work correctly, all segments must start at timestamp 0.
7923 All corresponding streams must have the same parameters in all segments; the
7924 filtering system will automatically select a common pixel format for video
7925 streams, and a common sample format, sample rate and channel layout for
7926 audio streams, but other settings, such as resolution, must be converted
7927 explicitly by the user.
7929 Different frame rates are acceptable but will result in variable frame rate
7930 at output; be sure to configure the output file to handle it.
7932 @subsection Examples
7936 Concatenate an opening, an episode and an ending, all in bilingual version
7937 (video in stream 0, audio in streams 1 and 2):
7939 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
7940 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
7941 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
7942 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
7946 Concatenate two parts, handling audio and video separately, using the
7947 (a)movie sources, and adjusting the resolution:
7949 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
7950 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
7951 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
7953 Note that a desync will happen at the stitch if the audio and video streams
7954 do not have exactly the same duration in the first file.
7960 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
7961 it unchanged. By default, it logs a message at a frequency of 10Hz with the
7962 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
7963 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
7965 The filter also has a video output (see the @var{video} option) with a real
7966 time graph to observe the loudness evolution. The graphic contains the logged
7967 message mentioned above, so it is not printed anymore when this option is set,
7968 unless the verbose logging is set. The main graphing area contains the
7969 short-term loudness (3 seconds of analysis), and the gauge on the right is for
7970 the momentary loudness (400 milliseconds).
7972 More information about the Loudness Recommendation EBU R128 on
7973 @url{http://tech.ebu.ch/loudness}.
7975 The filter accepts the following options:
7980 Activate the video output. The audio stream is passed unchanged whether this
7981 option is set or no. The video stream will be the first output stream if
7982 activated. Default is @code{0}.
7985 Set the video size. This option is for video only. Default and minimum
7986 resolution is @code{640x480}.
7989 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
7990 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
7991 other integer value between this range is allowed.
7994 Set metadata injection. If set to @code{1}, the audio input will be segmented
7995 into 100ms output frames, each of them containing various loudness information
7996 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
7998 Default is @code{0}.
8001 Force the frame logging level.
8003 Available values are:
8006 information logging level
8008 verbose logging level
8011 By default, the logging level is set to @var{info}. If the @option{video} or
8012 the @option{metadata} options are set, it switches to @var{verbose}.
8015 @subsection Examples
8019 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
8021 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
8025 Run an analysis with @command{ffmpeg}:
8027 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
8031 @section interleave, ainterleave
8033 Temporally interleave frames from several inputs.
8035 @code{interleave} works with video inputs, @code{ainterleave} with audio.
8037 These filters read frames from several inputs and send the oldest
8038 queued frame to the output.
8040 Input streams must have a well defined, monotonically increasing frame
8043 In order to submit one frame to output, these filters need to enqueue
8044 at least one frame for each input, so they cannot work in case one
8045 input is not yet terminated and will not receive incoming frames.
8047 For example consider the case when one input is a @code{select} filter
8048 which always drop input frames. The @code{interleave} filter will keep
8049 reading from that input, but it will never be able to send new frames
8050 to output until the input will send an end-of-stream signal.
8052 Also, depending on inputs synchronization, the filters will drop
8053 frames in case one input receives more frames than the other ones, and
8054 the queue is already filled.
8056 These filters accept the following options:
8060 Set the number of different inputs, it is 2 by default.
8063 @subsection Examples
8067 Interleave frames belonging to different streams using @command{ffmpeg}:
8069 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
8073 Add flickering blur effect:
8075 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
8079 @section perms, aperms
8081 Set read/write permissions for the output frames.
8083 These filters are mainly aimed at developers to test direct path in the
8084 following filter in the filtergraph.
8086 The filters accept the following options:
8090 Select the permissions mode.
8092 It accepts the following values:
8095 Do nothing. This is the default.
8097 Set all the output frames read-only.
8099 Set all the output frames directly writable.
8101 Make the frame read-only if writable, and writable if read-only.
8103 Set each output frame read-only or writable randomly.
8107 Set the seed for the @var{random} mode, must be an integer included between
8108 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
8109 @code{-1}, the filter will try to use a good random seed on a best effort
8113 Note: in case of auto-inserted filter between the permission filter and the
8114 following one, the permission might not be received as expected in that
8115 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
8116 perms/aperms filter can avoid this problem.
8118 @section select, aselect
8120 Select frames to pass in output.
8122 This filter accepts the following options:
8127 Set expression, which is evaluated for each input frame.
8129 If the expression is evaluated to zero, the frame is discarded.
8131 If the evaluation result is negative or NaN, the frame is sent to the
8132 first output; otherwise it is sent to the output with index
8133 @code{ceil(val)-1}, assuming that the input index starts from 0.
8135 For example a value of @code{1.2} corresponds to the output with index
8136 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
8139 Set the number of outputs. The output to which to send the selected
8140 frame is based on the result of the evaluation. Default value is 1.
8143 The expression can contain the following constants:
8147 the sequential number of the filtered frame, starting from 0
8150 the sequential number of the selected frame, starting from 0
8152 @item prev_selected_n
8153 the sequential number of the last selected frame, NAN if undefined
8156 timebase of the input timestamps
8159 the PTS (Presentation TimeStamp) of the filtered video frame,
8160 expressed in @var{TB} units, NAN if undefined
8163 the PTS (Presentation TimeStamp) of the filtered video frame,
8164 expressed in seconds, NAN if undefined
8167 the PTS of the previously filtered video frame, NAN if undefined
8169 @item prev_selected_pts
8170 the PTS of the last previously filtered video frame, NAN if undefined
8172 @item prev_selected_t
8173 the PTS of the last previously selected video frame, NAN if undefined
8176 the PTS of the first video frame in the video, NAN if undefined
8179 the time of the first video frame in the video, NAN if undefined
8181 @item pict_type @emph{(video only)}
8182 the type of the filtered frame, can assume one of the following
8194 @item interlace_type @emph{(video only)}
8195 the frame interlace type, can assume one of the following values:
8198 the frame is progressive (not interlaced)
8200 the frame is top-field-first
8202 the frame is bottom-field-first
8205 @item consumed_sample_n @emph{(audio only)}
8206 the number of selected samples before the current frame
8208 @item samples_n @emph{(audio only)}
8209 the number of samples in the current frame
8211 @item sample_rate @emph{(audio only)}
8212 the input sample rate
8215 1 if the filtered frame is a key-frame, 0 otherwise
8218 the position in the file of the filtered frame, -1 if the information
8219 is not available (e.g. for synthetic video)
8221 @item scene @emph{(video only)}
8222 value between 0 and 1 to indicate a new scene; a low value reflects a low
8223 probability for the current frame to introduce a new scene, while a higher
8224 value means the current frame is more likely to be one (see the example below)
8228 The default value of the select expression is "1".
8230 @subsection Examples
8234 Select all frames in input:
8239 The example above is the same as:
8251 Select only I-frames:
8253 select='eq(pict_type\,I)'
8257 Select one frame every 100:
8259 select='not(mod(n\,100))'
8263 Select only frames contained in the 10-20 time interval:
8265 select='gte(t\,10)*lte(t\,20)'
8269 Select only I frames contained in the 10-20 time interval:
8271 select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
8275 Select frames with a minimum distance of 10 seconds:
8277 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
8281 Use aselect to select only audio frames with samples number > 100:
8283 aselect='gt(samples_n\,100)'
8287 Create a mosaic of the first scenes:
8289 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
8292 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
8296 Send even and odd frames to separate outputs, and compose them:
8298 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
8302 @section sendcmd, asendcmd
8304 Send commands to filters in the filtergraph.
8306 These filters read commands to be sent to other filters in the
8309 @code{sendcmd} must be inserted between two video filters,
8310 @code{asendcmd} must be inserted between two audio filters, but apart
8311 from that they act the same way.
8313 The specification of commands can be provided in the filter arguments
8314 with the @var{commands} option, or in a file specified by the
8315 @var{filename} option.
8317 These filters accept the following options:
8320 Set the commands to be read and sent to the other filters.
8322 Set the filename of the commands to be read and sent to the other
8326 @subsection Commands syntax
8328 A commands description consists of a sequence of interval
8329 specifications, comprising a list of commands to be executed when a
8330 particular event related to that interval occurs. The occurring event
8331 is typically the current frame time entering or leaving a given time
8334 An interval is specified by the following syntax:
8336 @var{START}[-@var{END}] @var{COMMANDS};
8339 The time interval is specified by the @var{START} and @var{END} times.
8340 @var{END} is optional and defaults to the maximum time.
8342 The current frame time is considered within the specified interval if
8343 it is included in the interval [@var{START}, @var{END}), that is when
8344 the time is greater or equal to @var{START} and is lesser than
8347 @var{COMMANDS} consists of a sequence of one or more command
8348 specifications, separated by ",", relating to that interval. The
8349 syntax of a command specification is given by:
8351 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
8354 @var{FLAGS} is optional and specifies the type of events relating to
8355 the time interval which enable sending the specified command, and must
8356 be a non-null sequence of identifier flags separated by "+" or "|" and
8357 enclosed between "[" and "]".
8359 The following flags are recognized:
8362 The command is sent when the current frame timestamp enters the
8363 specified interval. In other words, the command is sent when the
8364 previous frame timestamp was not in the given interval, and the
8368 The command is sent when the current frame timestamp leaves the
8369 specified interval. In other words, the command is sent when the
8370 previous frame timestamp was in the given interval, and the
8374 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
8377 @var{TARGET} specifies the target of the command, usually the name of
8378 the filter class or a specific filter instance name.
8380 @var{COMMAND} specifies the name of the command for the target filter.
8382 @var{ARG} is optional and specifies the optional list of argument for
8383 the given @var{COMMAND}.
8385 Between one interval specification and another, whitespaces, or
8386 sequences of characters starting with @code{#} until the end of line,
8387 are ignored and can be used to annotate comments.
8389 A simplified BNF description of the commands specification syntax
8392 @var{COMMAND_FLAG} ::= "enter" | "leave"
8393 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
8394 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
8395 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
8396 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
8397 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
8400 @subsection Examples
8404 Specify audio tempo change at second 4:
8406 asendcmd=c='4.0 atempo tempo 1.5',atempo
8410 Specify a list of drawtext and hue commands in a file.
8412 # show text in the interval 5-10
8413 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
8414 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
8416 # desaturate the image in the interval 15-20
8417 15.0-20.0 [enter] hue s 0,
8418 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
8420 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
8422 # apply an exponential saturation fade-out effect, starting from time 25
8423 25 [enter] hue s exp(25-t)
8426 A filtergraph allowing to read and process the above command list
8427 stored in a file @file{test.cmd}, can be specified with:
8429 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
8434 @section setpts, asetpts
8436 Change the PTS (presentation timestamp) of the input frames.
8438 @code{setpts} works on video frames, @code{asetpts} on audio frames.
8440 This filter accepts the following options:
8445 The expression which is evaluated for each frame to construct its timestamp.
8449 The expression is evaluated through the eval API and can contain the following
8454 frame rate, only defined for constant frame-rate video
8457 the presentation timestamp in input
8460 the count of the input frame for video or the number of consumed samples,
8461 not including the current frame for audio, starting from 0.
8463 @item NB_CONSUMED_SAMPLES
8464 the number of consumed samples, not including the current frame (only
8468 the number of samples in the current frame (only audio)
8470 @item SAMPLE_RATE, SR
8474 the PTS of the first frame
8477 the time in seconds of the first frame
8480 tell if the current frame is interlaced
8483 the time in seconds of the current frame
8489 original position in the file of the frame, or undefined if undefined
8490 for the current frame
8496 previous input time in seconds
8502 previous output time in seconds
8505 wallclock (RTC) time in microseconds. This is deprecated, use time(0)
8509 wallclock (RTC) time at the start of the movie in microseconds
8512 @subsection Examples
8516 Start counting PTS from zero
8522 Apply fast motion effect:
8528 Apply slow motion effect:
8534 Set fixed rate of 25 frames per second:
8540 Set fixed rate 25 fps with some jitter:
8542 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
8546 Apply an offset of 10 seconds to the input PTS:
8552 Generate timestamps from a "live source" and rebase onto the current timebase:
8554 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
8558 Generate timestamps by counting samples:
8565 @section settb, asettb
8567 Set the timebase to use for the output frames timestamps.
8568 It is mainly useful for testing timebase configuration.
8570 This filter accepts the following options:
8575 The expression which is evaluated into the output timebase.
8579 The value for @option{tb} is an arithmetic expression representing a
8580 rational. The expression can contain the constants "AVTB" (the default
8581 timebase), "intb" (the input timebase) and "sr" (the sample rate,
8582 audio only). Default value is "intb".
8584 @subsection Examples
8588 Set the timebase to 1/25:
8594 Set the timebase to 1/10:
8600 Set the timebase to 1001/1000:
8606 Set the timebase to 2*intb:
8612 Set the default timebase value:
8618 @section showspectrum
8620 Convert input audio to a video output, representing the audio frequency
8623 The filter accepts the following options:
8627 Specify the video size for the output. Default value is @code{640x512}.
8630 Specify if the spectrum should slide along the window. Default value is
8634 Specify display mode.
8636 It accepts the following values:
8639 all channels are displayed in the same row
8641 all channels are displayed in separate rows
8644 Default value is @samp{combined}.
8647 Specify display color mode.
8649 It accepts the following values:
8652 each channel is displayed in a separate color
8654 each channel is is displayed using the same color scheme
8657 Default value is @samp{channel}.
8660 Specify scale used for calculating intensity color values.
8662 It accepts the following values:
8667 square root, default
8674 Default value is @samp{sqrt}.
8677 Set saturation modifier for displayed colors. Negative values provide
8678 alternative color scheme. @code{0} is no saturation at all.
8679 Saturation must be in [-10.0, 10.0] range.
8680 Default value is @code{1}.
8683 The usage is very similar to the showwaves filter; see the examples in that
8686 @subsection Examples
8690 Large window with logarithmic color scaling:
8692 showspectrum=s=1280x480:scale=log
8696 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
8698 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
8699 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
8705 Convert input audio to a video output, representing the samples waves.
8707 The filter accepts the following options:
8711 Specify the video size for the output. Default value is "600x240".
8716 Available values are:
8719 Draw a point for each sample.
8722 Draw a vertical line for each sample.
8725 Default value is @code{point}.
8728 Set the number of samples which are printed on the same column. A
8729 larger value will decrease the frame rate. Must be a positive
8730 integer. This option can be set only if the value for @var{rate}
8731 is not explicitly specified.
8734 Set the (approximate) output frame rate. This is done by setting the
8735 option @var{n}. Default value is "25".
8739 @subsection Examples
8743 Output the input file audio and the corresponding video representation
8746 amovie=a.mp3,asplit[out0],showwaves[out1]
8750 Create a synthetic signal and show it with showwaves, forcing a
8751 frame rate of 30 frames per second:
8753 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
8757 @section split, asplit
8759 Split input into several identical outputs.
8761 @code{asplit} works with audio input, @code{split} with video.
8763 The filter accepts a single parameter which specifies the number of outputs. If
8764 unspecified, it defaults to 2.
8766 @subsection Examples
8770 Create two separate outputs from the same input:
8772 [in] split [out0][out1]
8776 To create 3 or more outputs, you need to specify the number of
8779 [in] asplit=3 [out0][out1][out2]
8783 Create two separate outputs from the same input, one cropped and
8786 [in] split [splitout1][splitout2];
8787 [splitout1] crop=100:100:0:0 [cropout];
8788 [splitout2] pad=200:200:100:100 [padout];
8792 Create 5 copies of the input audio with @command{ffmpeg}:
8794 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
8800 Receive commands sent through a libzmq client, and forward them to
8801 filters in the filtergraph.
8803 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
8804 must be inserted between two video filters, @code{azmq} between two
8807 To enable these filters you need to install the libzmq library and
8808 headers and configure FFmpeg with @code{--enable-libzmq}.
8810 For more information about libzmq see:
8811 @url{http://www.zeromq.org/}
8813 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
8814 receives messages sent through a network interface defined by the
8815 @option{bind_address} option.
8817 The received message must be in the form:
8819 @var{TARGET} @var{COMMAND} [@var{ARG}]
8822 @var{TARGET} specifies the target of the command, usually the name of
8823 the filter class or a specific filter instance name.
8825 @var{COMMAND} specifies the name of the command for the target filter.
8827 @var{ARG} is optional and specifies the optional argument list for the
8828 given @var{COMMAND}.
8830 Upon reception, the message is processed and the corresponding command
8831 is injected into the filtergraph. Depending on the result, the filter
8832 will send a reply to the client, adopting the format:
8834 @var{ERROR_CODE} @var{ERROR_REASON}
8838 @var{MESSAGE} is optional.
8840 @subsection Examples
8842 Look at @file{tools/zmqsend} for an example of a zmq client which can
8843 be used to send commands processed by these filters.
8845 Consider the following filtergraph generated by @command{ffplay}
8847 ffplay -dumpgraph 1 -f lavfi "
8848 color=s=100x100:c=red [l];
8849 color=s=100x100:c=blue [r];
8850 nullsrc=s=200x100, zmq [bg];
8851 [bg][l] overlay [bg+l];
8852 [bg+l][r] overlay=x=100 "
8855 To change the color of the left side of the video, the following
8856 command can be used:
8858 echo Parsed_color_0 c yellow | tools/zmqsend
8861 To change the right side:
8863 echo Parsed_color_1 c pink | tools/zmqsend
8866 @c man end MULTIMEDIA FILTERS
8868 @chapter Multimedia Sources
8869 @c man begin MULTIMEDIA SOURCES
8871 Below is a description of the currently available multimedia sources.
8875 This is the same as @ref{movie} source, except it selects an audio
8881 Read audio and/or video stream(s) from a movie container.
8883 This filter accepts the following options:
8887 The name of the resource to read (not necessarily a file but also a device or a
8888 stream accessed through some protocol).
8890 @item format_name, f
8891 Specifies the format assumed for the movie to read, and can be either
8892 the name of a container or an input device. If not specified the
8893 format is guessed from @var{movie_name} or by probing.
8895 @item seek_point, sp
8896 Specifies the seek point in seconds, the frames will be output
8897 starting from this seek point, the parameter is evaluated with
8898 @code{av_strtod} so the numerical value may be suffixed by an IS
8899 postfix. Default value is "0".
8902 Specifies the streams to read. Several streams can be specified,
8903 separated by "+". The source will then have as many outputs, in the
8904 same order. The syntax is explained in the ``Stream specifiers''
8905 section in the ffmpeg manual. Two special names, "dv" and "da" specify
8906 respectively the default (best suited) video and audio stream. Default
8907 is "dv", or "da" if the filter is called as "amovie".
8909 @item stream_index, si
8910 Specifies the index of the video stream to read. If the value is -1,
8911 the best suited video stream will be automatically selected. Default
8912 value is "-1". Deprecated. If the filter is called "amovie", it will select
8913 audio instead of video.
8916 Specifies how many times to read the stream in sequence.
8917 If the value is less than 1, the stream will be read again and again.
8918 Default value is "1".
8920 Note that when the movie is looped the source timestamps are not
8921 changed, so it will generate non monotonically increasing timestamps.
8924 This filter allows to overlay a second video on top of main input of
8925 a filtergraph as shown in this graph:
8927 input -----------> deltapts0 --> overlay --> output
8930 movie --> scale--> deltapts1 -------+
8933 @subsection Examples
8937 Skip 3.2 seconds from the start of the avi file in.avi, and overlay it
8938 on top of the input labelled as "in":
8940 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
8941 [in] setpts=PTS-STARTPTS [main];
8942 [main][over] overlay=16:16 [out]
8946 Read from a video4linux2 device, and overlay it on top of the input
8949 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
8950 [in] setpts=PTS-STARTPTS [main];
8951 [main][over] overlay=16:16 [out]
8955 Read the first video stream and the audio stream with id 0x81 from
8956 dvd.vob; the video is connected to the pad named "video" and the audio is
8957 connected to the pad named "audio":
8959 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
8963 @c man end MULTIMEDIA SOURCES