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 echoing to the input audio.
354 Echoes are reflected sound and can occur naturally amongst mountains
355 (and sometimes large buildings) when talking or shouting; digital echo
356 effects emulate this behaviour and are often used to help fill out the
357 sound of a single instrument or vocal. The time difference between the
358 original signal and the reflection is the @code{delay}, and the
359 loudness of the reflected signal is the @code{decay}.
360 Multiple echoes can have different delays and decays.
362 A description of the accepted parameters follows.
366 Set input gain of reflected signal. Default is @code{0.6}.
369 Set output gain of reflected signal. Default is @code{0.3}.
372 Set list of time intervals in milliseconds between original signal and reflections
373 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
374 Default is @code{1000}.
377 Set list of loudnesses of reflected signals separated by '|'.
378 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
379 Default is @code{0.5}.
386 Make it sound as if there are twice as many instruments as are actually playing:
388 aecho=0.8:0.88:60:0.4
392 If delay is very short, then it sound like a (metallic) robot playing music:
398 A longer delay will sound like an open air concert in the mountains:
400 aecho=0.8:0.9:1000:0.3
404 Same as above but with one more mountain:
406 aecho=0.8:0.9:1000|1800:0.3|0.25
412 Apply fade-in/out effect to input audio.
414 A description of the accepted parameters follows.
418 Specify the effect type, can be either @code{in} for fade-in, or
419 @code{out} for a fade-out effect. Default is @code{in}.
421 @item start_sample, ss
422 Specify the number of the start sample for starting to apply the fade
423 effect. Default is 0.
426 Specify the number of samples for which the fade effect has to last. At
427 the end of the fade-in effect the output audio will have the same
428 volume as the input audio, at the end of the fade-out transition
429 the output audio will be silence. Default is 44100.
432 Specify time for starting to apply the fade effect. Default is 0.
433 The accepted syntax is:
435 [-]HH[:MM[:SS[.m...]]]
438 See also the function @code{av_parse_time()}.
439 If set this option is used instead of @var{start_sample} one.
442 Specify the duration for which the fade effect has to last. Default is 0.
443 The accepted syntax is:
445 [-]HH[:MM[:SS[.m...]]]
448 See also the function @code{av_parse_time()}.
449 At the end of the fade-in effect the output audio will have the same
450 volume as the input audio, at the end of the fade-out transition
451 the output audio will be silence.
452 If set this option is used instead of @var{nb_samples} one.
455 Set curve for fade transition.
457 It accepts the following values:
460 select triangular, linear slope (default)
462 select quarter of sine wave
464 select half of sine wave
466 select exponential sine wave
470 select inverted parabola
486 Fade in first 15 seconds of audio:
492 Fade out last 25 seconds of a 900 seconds audio:
494 afade=t=out:st=875:d=25
501 Set output format constraints for the input audio. The framework will
502 negotiate the most appropriate format to minimize conversions.
504 The filter accepts the following named parameters:
508 A '|'-separated list of requested sample formats.
511 A '|'-separated list of requested sample rates.
513 @item channel_layouts
514 A '|'-separated list of requested channel layouts.
518 If a parameter is omitted, all values are allowed.
520 For example to force the output to either unsigned 8-bit or signed 16-bit stereo:
522 aformat=sample_fmts=u8|s16:channel_layouts=stereo
527 Apply a two-pole all-pass filter with central frequency (in Hz)
528 @var{frequency}, and filter-width @var{width}.
529 An all-pass filter changes the audio's frequency to phase relationship
530 without changing its frequency to amplitude relationship.
532 The filter accepts the following options:
539 Set method to specify band-width of filter.
552 Specify the band-width of a filter in width_type units.
557 Merge two or more audio streams into a single multi-channel stream.
559 The filter accepts the following options:
564 Set the number of inputs. Default is 2.
568 If the channel layouts of the inputs are disjoint, and therefore compatible,
569 the channel layout of the output will be set accordingly and the channels
570 will be reordered as necessary. If the channel layouts of the inputs are not
571 disjoint, the output will have all the channels of the first input then all
572 the channels of the second input, in that order, and the channel layout of
573 the output will be the default value corresponding to the total number of
576 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
577 is FC+BL+BR, then the output will be in 5.1, with the channels in the
578 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
579 first input, b1 is the first channel of the second input).
581 On the other hand, if both input are in stereo, the output channels will be
582 in the default order: a1, a2, b1, b2, and the channel layout will be
583 arbitrarily set to 4.0, which may or may not be the expected value.
585 All inputs must have the same sample rate, and format.
587 If inputs do not have the same duration, the output will stop with the
594 Merge two mono files into a stereo stream:
596 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
600 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
602 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
608 Mixes multiple audio inputs into a single output.
612 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
614 will mix 3 input audio streams to a single output with the same duration as the
615 first input and a dropout transition time of 3 seconds.
617 The filter accepts the following named parameters:
621 Number of inputs. If unspecified, it defaults to 2.
624 How to determine the end-of-stream.
628 Duration of longest input. (default)
631 Duration of shortest input.
634 Duration of first input.
638 @item dropout_transition
639 Transition time, in seconds, for volume renormalization when an input
640 stream ends. The default value is 2 seconds.
646 Pass the audio source unchanged to the output.
650 Pad the end of a audio stream with silence, this can be used together with
651 -shortest to extend audio streams to the same length as the video stream.
654 Add a phasing effect to the input audio.
656 A phaser filter creates series of peaks and troughs in the frequency spectrum.
657 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
659 A description of the accepted parameters follows.
663 Set input gain. Default is 0.4.
666 Set output gain. Default is 0.74
669 Set delay in milliseconds. Default is 3.0.
672 Set decay. Default is 0.4.
675 Set modulation speed in Hz. Default is 0.5.
678 Set modulation type. Default is triangular.
680 It accepts the following values:
690 Resample the input audio to the specified parameters, using the
691 libswresample library. If none are specified then the filter will
692 automatically convert between its input and output.
694 This filter is also able to stretch/squeeze the audio data to make it match
695 the timestamps or to inject silence / cut out audio to make it match the
696 timestamps, do a combination of both or do neither.
698 The filter accepts the syntax
699 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
700 expresses a sample rate and @var{resampler_options} is a list of
701 @var{key}=@var{value} pairs, separated by ":". See the
702 ffmpeg-resampler manual for the complete list of supported options.
708 Resample the input audio to 44100Hz:
714 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
715 samples per second compensation:
721 @section asetnsamples
723 Set the number of samples per each output audio frame.
725 The last output packet may contain a different number of samples, as
726 the filter will flush all the remaining samples when the input audio
729 The filter accepts the following options:
733 @item nb_out_samples, n
734 Set the number of frames per each output audio frame. The number is
735 intended as the number of samples @emph{per each channel}.
736 Default value is 1024.
739 If set to 1, the filter will pad the last audio frame with zeroes, so
740 that the last frame will contain the same number of samples as the
741 previous ones. Default value is 1.
744 For example, to set the number of per-frame samples to 1234 and
745 disable padding for the last frame, use:
747 asetnsamples=n=1234:p=0
752 Set the sample rate without altering the PCM data.
753 This will result in a change of speed and pitch.
755 The filter accepts the following options:
759 Set the output sample rate. Default is 44100 Hz.
764 Show a line containing various information for each input audio frame.
765 The input audio is not modified.
767 The shown line contains a sequence of key/value pairs of the form
768 @var{key}:@var{value}.
770 A description of each shown parameter follows:
774 sequential number of the input frame, starting from 0
777 Presentation timestamp of the input frame, in time base units; the time base
778 depends on the filter input pad, and is usually 1/@var{sample_rate}.
781 presentation timestamp of the input frame in seconds
784 position of the frame in the input stream, -1 if this information in
785 unavailable and/or meaningless (for example in case of synthetic audio)
794 sample rate for the audio frame
797 number of samples (per channel) in the frame
800 Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio
801 the data is treated as if all the planes were concatenated.
803 @item plane_checksums
804 A list of Adler-32 checksums for each data plane.
809 Display time domain statistical information about the audio channels.
810 Statistics are calculated and displayed for each audio channel and,
811 where applicable, an overall figure is also given.
813 The filter accepts the following option:
816 Short window length in seconds, used for peak and trough RMS measurement.
817 Default is @code{0.05} (50 miliseconds). Allowed range is @code{[0.1 - 10]}.
820 A description of each shown parameter follows:
824 Mean amplitude displacement from zero.
827 Minimal sample level.
830 Maximal sample level.
834 Standard peak and RMS level measured in dBFS.
838 Peak and trough values for RMS level measured over a short window.
841 Standard ratio of peak to RMS level (note: not in dB).
844 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
845 (i.e. either @var{Min level} or @var{Max level}).
848 Number of occasions (not the number of samples) that the signal attained either
849 @var{Min level} or @var{Max level}.
854 Forward two audio streams and control the order the buffers are forwarded.
856 The filter accepts the following options:
860 Set the expression deciding which stream should be
861 forwarded next: if the result is negative, the first stream is forwarded; if
862 the result is positive or zero, the second stream is forwarded. It can use
863 the following variables:
867 number of buffers forwarded so far on each stream
869 number of samples forwarded so far on each stream
871 current timestamp of each stream
874 The default value is @code{t1-t2}, which means to always forward the stream
875 that has a smaller timestamp.
880 Stress-test @code{amerge} by randomly sending buffers on the wrong
881 input, while avoiding too much of a desynchronization:
883 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
884 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
890 Synchronize audio data with timestamps by squeezing/stretching it and/or
891 dropping samples/adding silence when needed.
893 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
895 The filter accepts the following named parameters:
899 Enable stretching/squeezing the data to make it match the timestamps. Disabled
900 by default. When disabled, time gaps are covered with silence.
903 Minimum difference between timestamps and audio data (in seconds) to trigger
904 adding/dropping samples. Default value is 0.1. If you get non-perfect sync with
905 this filter, try setting this parameter to 0.
908 Maximum compensation in samples per second. Relevant only with compensate=1.
912 Assume the first pts should be this value. The time base is 1 / sample rate.
913 This allows for padding/trimming at the start of stream. By default, no
914 assumption is made about the first frame's expected pts, so no padding or
915 trimming is done. For example, this could be set to 0 to pad the beginning with
916 silence if an audio stream starts after the video stream or to trim any samples
917 with a negative pts due to encoder delay.
925 The filter accepts exactly one parameter, the audio tempo. If not
926 specified then the filter will assume nominal 1.0 tempo. Tempo must
927 be in the [0.5, 2.0] range.
933 Slow down audio to 80% tempo:
939 To speed up audio to 125% tempo:
947 Trim the input so that the output contains one continuous subpart of the input.
949 This filter accepts the following options:
952 Specify time of the start of the kept section, i.e. the audio sample
953 with the timestamp @var{start} will be the first sample in the output.
956 Specify time of the first audio sample that will be dropped, i.e. the
957 audio sample immediately preceding the one with the timestamp @var{end} will be
958 the last sample in the output.
961 Same as @var{start}, except this option sets the start timestamp in samples
965 Same as @var{end}, except this option sets the end timestamp in samples instead
969 Specify maximum duration of the output.
972 Number of the first sample that should be passed to output.
975 Number of the first sample that should be dropped.
978 @option{start}, @option{end}, @option{duration} are expressed as time
979 duration specifications, check the "Time duration" section in the
982 Note that the first two sets of the start/end options and the @option{duration}
983 option look at the frame timestamp, while the _sample options simply count the
984 samples that pass through the filter. So start/end_pts and start/end_sample will
985 give different results when the timestamps are wrong, inexact or do not start at
986 zero. Also note that this filter does not modify the timestamps. If you wish
987 that the output timestamps start at zero, insert the asetpts filter after the
990 If multiple start or end options are set, this filter tries to be greedy and
991 keep all samples that match at least one of the specified constraints. To keep
992 only the part that matches all the constraints at once, chain multiple atrim
995 The defaults are such that all the input is kept. So it is possible to set e.g.
996 just the end values to keep everything before the specified time.
1001 drop everything except the second minute of input
1003 ffmpeg -i INPUT -af atrim=60:120
1007 keep only the first 1000 samples
1009 ffmpeg -i INPUT -af atrim=end_sample=1000
1016 Apply a two-pole Butterworth band-pass filter with central
1017 frequency @var{frequency}, and (3dB-point) band-width width.
1018 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1019 instead of the default: constant 0dB peak gain.
1020 The filter roll off at 6dB per octave (20dB per decade).
1022 The filter accepts the following options:
1026 Set the filter's central frequency. Default is @code{3000}.
1029 Constant skirt gain if set to 1. Defaults to 0.
1032 Set method to specify band-width of filter.
1045 Specify the band-width of a filter in width_type units.
1050 Apply a two-pole Butterworth band-reject filter with central
1051 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1052 The filter roll off at 6dB per octave (20dB per decade).
1054 The filter accepts the following options:
1058 Set the filter's central frequency. Default is @code{3000}.
1061 Set method to specify band-width of filter.
1074 Specify the band-width of a filter in width_type units.
1079 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1080 shelving filter with a response similar to that of a standard
1081 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1083 The filter accepts the following options:
1087 Give the gain at 0 Hz. Its useful range is about -20
1088 (for a large cut) to +20 (for a large boost).
1089 Beware of clipping when using a positive gain.
1092 Set the filter's central frequency and so can be used
1093 to extend or reduce the frequency range to be boosted or cut.
1094 The default value is @code{100} Hz.
1097 Set method to specify band-width of filter.
1110 Determine how steep is the filter's shelf transition.
1115 Apply a biquad IIR filter with the given coefficients.
1116 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1117 are the numerator and denominator coefficients respectively.
1121 Remap input channels to new locations.
1123 This filter accepts the following named parameters:
1125 @item channel_layout
1126 Channel layout of the output stream.
1129 Map channels from input to output. The argument is a '|'-separated list of
1130 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1131 @var{in_channel} form. @var{in_channel} can be either the name of the input
1132 channel (e.g. FL for front left) or its index in the input channel layout.
1133 @var{out_channel} is the name of the output channel or its index in the output
1134 channel layout. If @var{out_channel} is not given then it is implicitly an
1135 index, starting with zero and increasing by one for each mapping.
1138 If no mapping is present, the filter will implicitly map input channels to
1139 output channels preserving index.
1141 For example, assuming a 5.1+downmix input MOV file
1143 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1145 will create an output WAV file tagged as stereo from the downmix channels of
1148 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1150 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1153 @section channelsplit
1155 Split each channel in input audio stream into a separate output stream.
1157 This filter accepts the following named parameters:
1159 @item channel_layout
1160 Channel layout of the input stream. Default is "stereo".
1163 For example, assuming a stereo input MP3 file
1165 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1167 will create an output Matroska file with two audio streams, one containing only
1168 the left channel and the other the right channel.
1170 To split a 5.1 WAV file into per-channel files
1172 ffmpeg -i in.wav -filter_complex
1173 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1174 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1175 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1181 Compress or expand audio dynamic range.
1183 A description of the accepted options follows.
1188 Set list of times in seconds for each channel over which the instantaneous
1189 level of the input signal is averaged to determine its volume.
1190 @option{attacks} refers to increase of volume and @option{decays} refers
1191 to decrease of volume.
1192 For most situations, the attack time (response to the audio getting louder)
1193 should be shorter than the decay time because the human ear is more sensitive
1194 to sudden loud audio than sudden soft audio.
1195 Typical value for attack is @code{0.3} seconds and for decay @code{0.8}
1199 Set list of points for transfer function, specified in dB relative to maximum
1200 possible signal amplitude.
1201 Each key points list need to be defined using the following syntax:
1202 @code{x0/y0 x1/y1 x2/y2 ...}.
1204 The input values must be in strictly increasing order but the transfer
1205 function does not have to be monotonically rising.
1206 The point @code{0/0} is assumed but may be overridden (by @code{0/out-dBn}).
1207 Typical values for the transfer function are @code{-70/-70 -60/-20}.
1210 Set amount for which the points at where adjacent line segments on the
1211 transfer function meet will be rounded. Defaults is @code{0.01}.
1214 Set additional gain in dB to be applied at all points on the transfer function
1215 and allows easy adjustment of the overall gain.
1216 Default is @code{0}.
1219 Set initial volume in dB to be assumed for each channel when filtering starts.
1220 This permits the user to supply a nominal level initially, so that,
1221 for example, a very large gain is not applied to initial signal levels before
1222 the companding has begun to operate. A typical value for audio which is
1223 initially quiet is -90 dB. Default is @code{0}.
1226 Set delay in seconds. Default is @code{0}. The input audio
1227 is analysed immediately, but audio is delayed before being fed to the
1228 volume adjuster. Specifying a delay approximately equal to the attack/decay
1229 times allows the filter to effectively operate in predictive rather than
1233 @subsection Examples
1236 Make music with both quiet and loud passages suitable for listening
1237 in a noisy environment:
1239 compand=.3 .3:1 1:-90/-60 -60/-40 -40/-30 -20/-20:6:0:-90:0.2
1243 Noise-gate for when the noise is at a lower level than the signal:
1245 compand=.1 .1:.2 .2:-900/-900 -50.1/-900 -50/-50:.01:0:-90:.1
1249 Here is another noise-gate, this time for when the noise is at a higher level
1250 than the signal (making it, in some ways, similar to squelch):
1252 compand=.1 .1:.1 .1:-45.1/-45.1 -45/-900 0/-900:.01:45:-90:.1
1258 Make audio easier to listen to on headphones.
1260 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1261 so that when listened to on headphones the stereo image is moved from
1262 inside your head (standard for headphones) to outside and in front of
1263 the listener (standard for speakers).
1269 Apply a two-pole peaking equalisation (EQ) filter. With this
1270 filter, the signal-level at and around a selected frequency can
1271 be increased or decreased, whilst (unlike bandpass and bandreject
1272 filters) that at all other frequencies is unchanged.
1274 In order to produce complex equalisation curves, this filter can
1275 be given several times, each with a different central frequency.
1277 The filter accepts the following options:
1281 Set the filter's central frequency in Hz.
1284 Set method to specify band-width of filter.
1297 Specify the band-width of a filter in width_type units.
1300 Set the required gain or attenuation in dB.
1301 Beware of clipping when using a positive gain.
1306 Apply a high-pass filter with 3dB point frequency.
1307 The filter can be either single-pole, or double-pole (the default).
1308 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1310 The filter accepts the following options:
1314 Set frequency in Hz. Default is 3000.
1317 Set number of poles. Default is 2.
1320 Set method to specify band-width of filter.
1333 Specify the band-width of a filter in width_type units.
1334 Applies only to double-pole filter.
1335 The default is 0.707q and gives a Butterworth response.
1340 Join multiple input streams into one multi-channel stream.
1342 The filter accepts the following named parameters:
1346 Number of input streams. Defaults to 2.
1348 @item channel_layout
1349 Desired output channel layout. Defaults to stereo.
1352 Map channels from inputs to output. The argument is a '|'-separated list of
1353 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1354 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1355 can be either the name of the input channel (e.g. FL for front left) or its
1356 index in the specified input stream. @var{out_channel} is the name of the output
1360 The filter will attempt to guess the mappings when those are not specified
1361 explicitly. It does so by first trying to find an unused matching input channel
1362 and if that fails it picks the first unused input channel.
1364 E.g. to join 3 inputs (with properly set channel layouts)
1366 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1369 To build a 5.1 output from 6 single-channel streams:
1371 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1372 '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'
1378 Apply a low-pass filter with 3dB point frequency.
1379 The filter can be either single-pole or double-pole (the default).
1380 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1382 The filter accepts the following options:
1386 Set frequency in Hz. Default is 500.
1389 Set number of poles. Default is 2.
1392 Set method to specify band-width of filter.
1405 Specify the band-width of a filter in width_type units.
1406 Applies only to double-pole filter.
1407 The default is 0.707q and gives a Butterworth response.
1412 Mix channels with specific gain levels. The filter accepts the output
1413 channel layout followed by a set of channels definitions.
1415 This filter is also designed to remap efficiently the channels of an audio
1418 The filter accepts parameters of the form:
1419 "@var{l}:@var{outdef}:@var{outdef}:..."
1423 output channel layout or number of channels
1426 output channel specification, of the form:
1427 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1430 output channel to define, either a channel name (FL, FR, etc.) or a channel
1431 number (c0, c1, etc.)
1434 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1437 input channel to use, see out_name for details; it is not possible to mix
1438 named and numbered input channels
1441 If the `=' in a channel specification is replaced by `<', then the gains for
1442 that specification will be renormalized so that the total is 1, thus
1443 avoiding clipping noise.
1445 @subsection Mixing examples
1447 For example, if you want to down-mix from stereo to mono, but with a bigger
1448 factor for the left channel:
1450 pan=1:c0=0.9*c0+0.1*c1
1453 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1454 7-channels surround:
1456 pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1459 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1460 that should be preferred (see "-ac" option) unless you have very specific
1463 @subsection Remapping examples
1465 The channel remapping will be effective if, and only if:
1468 @item gain coefficients are zeroes or ones,
1469 @item only one input per channel output,
1472 If all these conditions are satisfied, the filter will notify the user ("Pure
1473 channel mapping detected"), and use an optimized and lossless method to do the
1476 For example, if you have a 5.1 source and want a stereo audio stream by
1477 dropping the extra channels:
1479 pan="stereo: c0=FL : c1=FR"
1482 Given the same source, you can also switch front left and front right channels
1483 and keep the input channel layout:
1485 pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
1488 If the input is a stereo audio stream, you can mute the front left channel (and
1489 still keep the stereo channel layout) with:
1494 Still with a stereo audio stream input, you can copy the right channel in both
1495 front left and right:
1497 pan="stereo: c0=FR : c1=FR"
1502 Convert the audio sample format, sample rate and channel layout. This filter is
1503 not meant to be used directly.
1505 @section silencedetect
1507 Detect silence in an audio stream.
1509 This filter logs a message when it detects that the input audio volume is less
1510 or equal to a noise tolerance value for a duration greater or equal to the
1511 minimum detected noise duration.
1513 The printed times and duration are expressed in seconds.
1515 The filter accepts the following options:
1519 Set silence duration until notification (default is 2 seconds).
1522 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1523 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1526 @subsection Examples
1530 Detect 5 seconds of silence with -50dB noise tolerance:
1532 silencedetect=n=-50dB:d=5
1536 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1537 tolerance in @file{silence.mp3}:
1539 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1545 Boost or cut treble (upper) frequencies of the audio using a two-pole
1546 shelving filter with a response similar to that of a standard
1547 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1549 The filter accepts the following options:
1553 Give the gain at whichever is the lower of ~22 kHz and the
1554 Nyquist frequency. Its useful range is about -20 (for a large cut)
1555 to +20 (for a large boost). Beware of clipping when using a positive gain.
1558 Set the filter's central frequency and so can be used
1559 to extend or reduce the frequency range to be boosted or cut.
1560 The default value is @code{3000} Hz.
1563 Set method to specify band-width of filter.
1576 Determine how steep is the filter's shelf transition.
1581 Adjust the input audio volume.
1583 The filter accepts the following options:
1588 Expresses how the audio volume will be increased or decreased.
1590 Output values are clipped to the maximum value.
1592 The output audio volume is given by the relation:
1594 @var{output_volume} = @var{volume} * @var{input_volume}
1597 Default value for @var{volume} is 1.0.
1600 Set the mathematical precision.
1602 This determines which input sample formats will be allowed, which affects the
1603 precision of the volume scaling.
1607 8-bit fixed-point; limits input sample format to U8, S16, and S32.
1609 32-bit floating-point; limits input sample format to FLT. (default)
1611 64-bit floating-point; limits input sample format to DBL.
1615 @subsection Examples
1619 Halve the input audio volume:
1623 volume=volume=-6.0206dB
1626 In all the above example the named key for @option{volume} can be
1627 omitted, for example like in:
1633 Increase input audio power by 6 decibels using fixed-point precision:
1635 volume=volume=6dB:precision=fixed
1639 @section volumedetect
1641 Detect the volume of the input video.
1643 The filter has no parameters. The input is not modified. Statistics about
1644 the volume will be printed in the log when the input stream end is reached.
1646 In particular it will show the mean volume (root mean square), maximum
1647 volume (on a per-sample basis), and the beginning of a histogram of the
1648 registered volume values (from the maximum value to a cumulated 1/1000 of
1651 All volumes are in decibels relative to the maximum PCM value.
1653 @subsection Examples
1655 Here is an excerpt of the output:
1657 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
1658 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
1659 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
1660 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
1661 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
1662 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
1663 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
1664 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
1665 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
1671 The mean square energy is approximately -27 dB, or 10^-2.7.
1673 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
1675 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
1678 In other words, raising the volume by +4 dB does not cause any clipping,
1679 raising it by +5 dB causes clipping for 6 samples, etc.
1681 @c man end AUDIO FILTERS
1683 @chapter Audio Sources
1684 @c man begin AUDIO SOURCES
1686 Below is a description of the currently available audio sources.
1690 Buffer audio frames, and make them available to the filter chain.
1692 This source is mainly intended for a programmatic use, in particular
1693 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
1695 It accepts the following named parameters:
1700 Timebase which will be used for timestamps of submitted frames. It must be
1701 either a floating-point number or in @var{numerator}/@var{denominator} form.
1704 The sample rate of the incoming audio buffers.
1707 The sample format of the incoming audio buffers.
1708 Either a sample format name or its corresponging integer representation from
1709 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
1711 @item channel_layout
1712 The channel layout of the incoming audio buffers.
1713 Either a channel layout name from channel_layout_map in
1714 @file{libavutil/channel_layout.c} or its corresponding integer representation
1715 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
1718 The number of channels of the incoming audio buffers.
1719 If both @var{channels} and @var{channel_layout} are specified, then they
1724 @subsection Examples
1727 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
1730 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
1731 Since the sample format with name "s16p" corresponds to the number
1732 6 and the "stereo" channel layout corresponds to the value 0x3, this is
1735 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
1740 Generate an audio signal specified by an expression.
1742 This source accepts in input one or more expressions (one for each
1743 channel), which are evaluated and used to generate a corresponding
1746 This source accepts the following options:
1750 Set the '|'-separated expressions list for each separate channel. In case the
1751 @option{channel_layout} option is not specified, the selected channel layout
1752 depends on the number of provided expressions.
1754 @item channel_layout, c
1755 Set the channel layout. The number of channels in the specified layout
1756 must be equal to the number of specified expressions.
1759 Set the minimum duration of the sourced audio. See the function
1760 @code{av_parse_time()} for the accepted format.
1761 Note that the resulting duration may be greater than the specified
1762 duration, as the generated audio is always cut at the end of a
1765 If not specified, or the expressed duration is negative, the audio is
1766 supposed to be generated forever.
1769 Set the number of samples per channel per each output frame,
1772 @item sample_rate, s
1773 Specify the sample rate, default to 44100.
1776 Each expression in @var{exprs} can contain the following constants:
1780 number of the evaluated sample, starting from 0
1783 time of the evaluated sample expressed in seconds, starting from 0
1790 @subsection Examples
1800 Generate a sin signal with frequency of 440 Hz, set sample rate to
1803 aevalsrc="sin(440*2*PI*t):s=8000"
1807 Generate a two channels signal, specify the channel layout (Front
1808 Center + Back Center) explicitly:
1810 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
1814 Generate white noise:
1816 aevalsrc="-2+random(0)"
1820 Generate an amplitude modulated signal:
1822 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
1826 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
1828 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
1835 Null audio source, return unprocessed audio frames. It is mainly useful
1836 as a template and to be employed in analysis / debugging tools, or as
1837 the source for filters which ignore the input data (for example the sox
1840 This source accepts the following options:
1844 @item channel_layout, cl
1846 Specify the channel layout, and can be either an integer or a string
1847 representing a channel layout. The default value of @var{channel_layout}
1850 Check the channel_layout_map definition in
1851 @file{libavutil/channel_layout.c} for the mapping between strings and
1852 channel layout values.
1854 @item sample_rate, r
1855 Specify the sample rate, and defaults to 44100.
1858 Set the number of samples per requested frames.
1862 @subsection Examples
1866 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
1868 anullsrc=r=48000:cl=4
1872 Do the same operation with a more obvious syntax:
1874 anullsrc=r=48000:cl=mono
1878 All the parameters need to be explicitly defined.
1882 Synthesize a voice utterance using the libflite library.
1884 To enable compilation of this filter you need to configure FFmpeg with
1885 @code{--enable-libflite}.
1887 Note that the flite library is not thread-safe.
1889 The filter accepts the following options:
1894 If set to 1, list the names of the available voices and exit
1895 immediately. Default value is 0.
1898 Set the maximum number of samples per frame. Default value is 512.
1901 Set the filename containing the text to speak.
1904 Set the text to speak.
1907 Set the voice to use for the speech synthesis. Default value is
1908 @code{kal}. See also the @var{list_voices} option.
1911 @subsection Examples
1915 Read from file @file{speech.txt}, and synthetize the text using the
1916 standard flite voice:
1918 flite=textfile=speech.txt
1922 Read the specified text selecting the @code{slt} voice:
1924 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
1928 Input text to ffmpeg:
1930 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
1934 Make @file{ffplay} speak the specified text, using @code{flite} and
1935 the @code{lavfi} device:
1937 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
1941 For more information about libflite, check:
1942 @url{http://www.speech.cs.cmu.edu/flite/}
1946 Generate an audio signal made of a sine wave with amplitude 1/8.
1948 The audio signal is bit-exact.
1950 The filter accepts the following options:
1955 Set the carrier frequency. Default is 440 Hz.
1957 @item beep_factor, b
1958 Enable a periodic beep every second with frequency @var{beep_factor} times
1959 the carrier frequency. Default is 0, meaning the beep is disabled.
1961 @item sample_rate, r
1962 Specify the sample rate, default is 44100.
1965 Specify the duration of the generated audio stream.
1967 @item samples_per_frame
1968 Set the number of samples per output frame, default is 1024.
1971 @subsection Examples
1976 Generate a simple 440 Hz sine wave:
1982 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
1986 sine=frequency=220:beep_factor=4:duration=5
1991 @c man end AUDIO SOURCES
1993 @chapter Audio Sinks
1994 @c man begin AUDIO SINKS
1996 Below is a description of the currently available audio sinks.
1998 @section abuffersink
2000 Buffer audio frames, and make them available to the end of filter chain.
2002 This sink is mainly intended for programmatic use, in particular
2003 through the interface defined in @file{libavfilter/buffersink.h}
2004 or the options system.
2006 It accepts a pointer to an AVABufferSinkContext structure, which
2007 defines the incoming buffers' formats, to be passed as the opaque
2008 parameter to @code{avfilter_init_filter} for initialization.
2012 Null audio sink, do absolutely nothing with the input audio. It is
2013 mainly useful as a template and to be employed in analysis / debugging
2016 @c man end AUDIO SINKS
2018 @chapter Video Filters
2019 @c man begin VIDEO FILTERS
2021 When you configure your FFmpeg build, you can disable any of the
2022 existing filters using @code{--disable-filters}.
2023 The configure output will show the video filters included in your
2026 Below is a description of the currently available video filters.
2028 @section alphaextract
2030 Extract the alpha component from the input as a grayscale video. This
2031 is especially useful with the @var{alphamerge} filter.
2035 Add or replace the alpha component of the primary input with the
2036 grayscale value of a second input. This is intended for use with
2037 @var{alphaextract} to allow the transmission or storage of frame
2038 sequences that have alpha in a format that doesn't support an alpha
2041 For example, to reconstruct full frames from a normal YUV-encoded video
2042 and a separate video created with @var{alphaextract}, you might use:
2044 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2047 Since this filter is designed for reconstruction, it operates on frame
2048 sequences without considering timestamps, and terminates when either
2049 input reaches end of stream. This will cause problems if your encoding
2050 pipeline drops frames. If you're trying to apply an image as an
2051 overlay to a video stream, consider the @var{overlay} filter instead.
2055 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2056 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2057 Substation Alpha) subtitles files.
2061 Compute the bounding box for the non-black pixels in the input frame
2064 This filter computes the bounding box containing all the pixels with a
2065 luminance value greater than the minimum allowed value.
2066 The parameters describing the bounding box are printed on the filter
2069 The filter accepts the following option:
2073 Set the minimal luminance value. Default is @code{16}.
2076 @section blackdetect
2078 Detect video intervals that are (almost) completely black. Can be
2079 useful to detect chapter transitions, commercials, or invalid
2080 recordings. Output lines contains the time for the start, end and
2081 duration of the detected black interval expressed in seconds.
2083 In order to display the output lines, you need to set the loglevel at
2084 least to the AV_LOG_INFO value.
2086 The filter accepts the following options:
2089 @item black_min_duration, d
2090 Set the minimum detected black duration expressed in seconds. It must
2091 be a non-negative floating point number.
2093 Default value is 2.0.
2095 @item picture_black_ratio_th, pic_th
2096 Set the threshold for considering a picture "black".
2097 Express the minimum value for the ratio:
2099 @var{nb_black_pixels} / @var{nb_pixels}
2102 for which a picture is considered black.
2103 Default value is 0.98.
2105 @item pixel_black_th, pix_th
2106 Set the threshold for considering a pixel "black".
2108 The threshold expresses the maximum pixel luminance value for which a
2109 pixel is considered "black". The provided value is scaled according to
2110 the following equation:
2112 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2115 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2116 the input video format, the range is [0-255] for YUV full-range
2117 formats and [16-235] for YUV non full-range formats.
2119 Default value is 0.10.
2122 The following example sets the maximum pixel threshold to the minimum
2123 value, and detects only black intervals of 2 or more seconds:
2125 blackdetect=d=2:pix_th=0.00
2130 Detect frames that are (almost) completely black. Can be useful to
2131 detect chapter transitions or commercials. Output lines consist of
2132 the frame number of the detected frame, the percentage of blackness,
2133 the position in the file if known or -1 and the timestamp in seconds.
2135 In order to display the output lines, you need to set the loglevel at
2136 least to the AV_LOG_INFO value.
2138 The filter accepts the following options:
2143 Set the percentage of the pixels that have to be below the threshold, defaults
2146 @item threshold, thresh
2147 Set the threshold below which a pixel value is considered black, defaults to
2154 Blend two video frames into each other.
2156 It takes two input streams and outputs one stream, the first input is the
2157 "top" layer and second input is "bottom" layer.
2158 Output terminates when shortest input terminates.
2160 A description of the accepted options follows.
2168 Set blend mode for specific pixel component or all pixel components in case
2169 of @var{all_mode}. Default value is @code{normal}.
2171 Available values for component modes are:
2204 Set blend opacity for specific pixel component or all pixel components in case
2205 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2212 Set blend expression for specific pixel component or all pixel components in case
2213 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2215 The expressions can use the following variables:
2219 The sequential number of the filtered frame, starting from @code{0}.
2223 the coordinates of the current sample
2227 the width and height of currently filtered plane
2231 Width and height scale depending on the currently filtered plane. It is the
2232 ratio between the corresponding luma plane number of pixels and the current
2233 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2234 @code{0.5,0.5} for chroma planes.
2237 Time of the current frame, expressed in seconds.
2240 Value of pixel component at current location for first video frame (top layer).
2243 Value of pixel component at current location for second video frame (bottom layer).
2247 Force termination when the shortest input terminates. Default is @code{0}.
2249 Continue applying the last bottom frame after the end of the stream. A value of
2250 @code{0} disable the filter after the last frame of the bottom layer is reached.
2251 Default is @code{1}.
2254 @subsection Examples
2258 Apply transition from bottom layer to top layer in first 10 seconds:
2260 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2264 Apply 1x1 checkerboard effect:
2266 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2272 Apply boxblur algorithm to the input video.
2274 The filter accepts the following options:
2278 @item luma_radius, lr
2279 @item luma_power, lp
2280 @item chroma_radius, cr
2281 @item chroma_power, cp
2282 @item alpha_radius, ar
2283 @item alpha_power, ap
2287 A description of the accepted options follows.
2290 @item luma_radius, lr
2291 @item chroma_radius, cr
2292 @item alpha_radius, ar
2293 Set an expression for the box radius in pixels used for blurring the
2294 corresponding input plane.
2296 The radius value must be a non-negative number, and must not be
2297 greater than the value of the expression @code{min(w,h)/2} for the
2298 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2301 Default value for @option{luma_radius} is "2". If not specified,
2302 @option{chroma_radius} and @option{alpha_radius} default to the
2303 corresponding value set for @option{luma_radius}.
2305 The expressions can contain the following constants:
2309 the input width and height in pixels
2313 the input chroma image width and height in pixels
2317 horizontal and vertical chroma subsample values. For example for the
2318 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2321 @item luma_power, lp
2322 @item chroma_power, cp
2323 @item alpha_power, ap
2324 Specify how many times the boxblur filter is applied to the
2325 corresponding plane.
2327 Default value for @option{luma_power} is 2. If not specified,
2328 @option{chroma_power} and @option{alpha_power} default to the
2329 corresponding value set for @option{luma_power}.
2331 A value of 0 will disable the effect.
2334 @subsection Examples
2338 Apply a boxblur filter with luma, chroma, and alpha radius
2341 boxblur=luma_radius=2:luma_power=1
2346 Set luma radius to 2, alpha and chroma radius to 0:
2348 boxblur=2:1:cr=0:ar=0
2352 Set luma and chroma radius to a fraction of the video dimension:
2354 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2358 @section colorbalance
2359 Modify intensity of primary colors (red, green and blue) of input frames.
2361 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2362 regions for the red-cyan, green-magenta or blue-yellow balance.
2364 A positive adjustment value shifts the balance towards the primary color, a negative
2365 value towards the complementary color.
2367 The filter accepts the following options:
2373 Adjust red, green and blue shadows (darkest pixels).
2378 Adjust red, green and blue midtones (medium pixels).
2383 Adjust red, green and blue highlights (brightest pixels).
2385 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2388 @subsection Examples
2392 Add red color cast to shadows:
2398 @section colorchannelmixer
2400 Adjust video input frames by re-mixing color channels.
2402 This filter modifies a color channel by adding the values associated to
2403 the other channels of the same pixels. For example if the value to
2404 modify is red, the output value will be:
2406 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2409 The filter accepts the following options:
2416 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2417 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2423 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2424 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2430 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2431 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2437 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2438 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2440 Allowed ranges for options are @code{[-2.0, 2.0]}.
2443 @subsection Examples
2447 Convert source to grayscale:
2449 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2452 Simulate sepia tones:
2454 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
2458 @section colormatrix
2460 Convert color matrix.
2462 The filter accepts the following options:
2467 Specify the source and destination color matrix. Both values must be
2470 The accepted values are:
2486 For example to convert from BT.601 to SMPTE-240M, use the command:
2488 colormatrix=bt601:smpte240m
2493 Copy the input source unchanged to the output. Mainly useful for
2498 Crop the input video to given dimensions.
2500 The filter accepts the following options:
2504 Width of the output video. It defaults to @code{iw}.
2505 This expression is evaluated only once during the filter
2509 Height of the output video. It defaults to @code{ih}.
2510 This expression is evaluated only once during the filter
2514 Horizontal position, in the input video, of the left edge of the output video.
2515 It defaults to @code{(in_w-out_w)/2}.
2516 This expression is evaluated per-frame.
2519 Vertical position, in the input video, of the top edge of the output video.
2520 It defaults to @code{(in_h-out_h)/2}.
2521 This expression is evaluated per-frame.
2524 If set to 1 will force the output display aspect ratio
2525 to be the same of the input, by changing the output sample aspect
2526 ratio. It defaults to 0.
2529 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
2530 expressions containing the following constants:
2535 the computed values for @var{x} and @var{y}. They are evaluated for
2540 the input width and height
2544 same as @var{in_w} and @var{in_h}
2548 the output (cropped) width and height
2552 same as @var{out_w} and @var{out_h}
2555 same as @var{iw} / @var{ih}
2558 input sample aspect ratio
2561 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
2565 horizontal and vertical chroma subsample values. For example for the
2566 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2569 the number of input frame, starting from 0
2572 the position in the file of the input frame, NAN if unknown
2575 timestamp expressed in seconds, NAN if the input timestamp is unknown
2579 The expression for @var{out_w} may depend on the value of @var{out_h},
2580 and the expression for @var{out_h} may depend on @var{out_w}, but they
2581 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
2582 evaluated after @var{out_w} and @var{out_h}.
2584 The @var{x} and @var{y} parameters specify the expressions for the
2585 position of the top-left corner of the output (non-cropped) area. They
2586 are evaluated for each frame. If the evaluated value is not valid, it
2587 is approximated to the nearest valid value.
2589 The expression for @var{x} may depend on @var{y}, and the expression
2590 for @var{y} may depend on @var{x}.
2592 @subsection Examples
2596 Crop area with size 100x100 at position (12,34).
2601 Using named options, the example above becomes:
2603 crop=w=100:h=100:x=12:y=34
2607 Crop the central input area with size 100x100:
2613 Crop the central input area with size 2/3 of the input video:
2615 crop=2/3*in_w:2/3*in_h
2619 Crop the input video central square:
2626 Delimit the rectangle with the top-left corner placed at position
2627 100:100 and the right-bottom corner corresponding to the right-bottom
2628 corner of the input image:
2630 crop=in_w-100:in_h-100:100:100
2634 Crop 10 pixels from the left and right borders, and 20 pixels from
2635 the top and bottom borders
2637 crop=in_w-2*10:in_h-2*20
2641 Keep only the bottom right quarter of the input image:
2643 crop=in_w/2:in_h/2:in_w/2:in_h/2
2647 Crop height for getting Greek harmony:
2649 crop=in_w:1/PHI*in_w
2653 Appply trembling effect:
2655 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)
2659 Apply erratic camera effect depending on timestamp:
2661 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)"
2665 Set x depending on the value of y:
2667 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
2673 Auto-detect crop size.
2675 Calculate necessary cropping parameters and prints the recommended
2676 parameters through the logging system. The detected dimensions
2677 correspond to the non-black area of the input video.
2679 The filter accepts the following options:
2684 Set higher black value threshold, which can be optionally specified
2685 from nothing (0) to everything (255). An intensity value greater
2686 to the set value is considered non-black. Default value is 24.
2689 Set the value for which the width/height should be divisible by. The
2690 offset is automatically adjusted to center the video. Use 2 to get
2691 only even dimensions (needed for 4:2:2 video). 16 is best when
2692 encoding to most video codecs. Default value is 16.
2694 @item reset_count, reset
2695 Set the counter that determines after how many frames cropdetect will
2696 reset the previously detected largest video area and start over to
2697 detect the current optimal crop area. Default value is 0.
2699 This can be useful when channel logos distort the video area. 0
2700 indicates never reset and return the largest area encountered during
2707 Apply color adjustments using curves.
2709 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
2710 component (red, green and blue) has its values defined by @var{N} key points
2711 tied from each other using a smooth curve. The x-axis represents the pixel
2712 values from the input frame, and the y-axis the new pixel values to be set for
2715 By default, a component curve is defined by the two points @var{(0;0)} and
2716 @var{(1;1)}. This creates a straight line where each original pixel value is
2717 "adjusted" to its own value, which means no change to the image.
2719 The filter allows you to redefine these two points and add some more. A new
2720 curve (using a natural cubic spline interpolation) will be define to pass
2721 smoothly through all these new coordinates. The new defined points needs to be
2722 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
2723 be in the @var{[0;1]} interval. If the computed curves happened to go outside
2724 the vector spaces, the values will be clipped accordingly.
2726 If there is no key point defined in @code{x=0}, the filter will automatically
2727 insert a @var{(0;0)} point. In the same way, if there is no key point defined
2728 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
2730 The filter accepts the following options:
2734 Select one of the available color presets. This option can be used in addition
2735 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
2736 options takes priority on the preset values.
2737 Available presets are:
2740 @item color_negative
2743 @item increase_contrast
2745 @item linear_contrast
2746 @item medium_contrast
2748 @item strong_contrast
2751 Default is @code{none}.
2753 Set the master key points. These points will define a second pass mapping. It
2754 is sometimes called a "luminance" or "value" mapping. It can be used with
2755 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
2756 post-processing LUT.
2758 Set the key points for the red component.
2760 Set the key points for the green component.
2762 Set the key points for the blue component.
2764 Set the key points for all components (not including master).
2765 Can be used in addition to the other key points component
2766 options. In this case, the unset component(s) will fallback on this
2767 @option{all} setting.
2769 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
2772 To avoid some filtergraph syntax conflicts, each key points list need to be
2773 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
2775 @subsection Examples
2779 Increase slightly the middle level of blue:
2781 curves=blue='0.5/0.58'
2787 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
2789 Here we obtain the following coordinates for each components:
2792 @code{(0;0.11) (0.42;0.51) (1;0.95)}
2794 @code{(0;0) (0.50;0.48) (1;1)}
2796 @code{(0;0.22) (0.49;0.44) (1;0.80)}
2800 The previous example can also be achieved with the associated built-in preset:
2802 curves=preset=vintage
2812 Use a Photoshop preset and redefine the points of the green component:
2814 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
2820 Denoise frames using 2D DCT (frequency domain filtering).
2822 This filter is not designed for real time and can be extremely slow.
2824 The filter accepts the following options:
2828 Set the noise sigma constant.
2830 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
2831 coefficient (absolute value) below this threshold with be dropped.
2833 If you need a more advanced filtering, see @option{expr}.
2835 Default is @code{0}.
2838 Set number overlapping pixels for each block. Each block is of size
2839 @code{16x16}. Since the filter can be slow, you may want to reduce this value,
2840 at the cost of a less effective filter and the risk of various artefacts.
2842 If the overlapping value doesn't allow to process the whole input width or
2843 height, a warning will be displayed and according borders won't be denoised.
2845 Default value is @code{15}.
2848 Set the coefficient factor expression.
2850 For each coefficient of a DCT block, this expression will be evaluated as a
2851 multiplier value for the coefficient.
2853 If this is option is set, the @option{sigma} option will be ignored.
2855 The absolute value of the coefficient can be accessed through the @var{c}
2859 @subsection Examples
2861 Apply a denoise with a @option{sigma} of @code{4.5}:
2866 The same operation can be achieved using the expression system:
2868 dctdnoiz=e='gte(c, 4.5*3)'
2874 Drop duplicated frames at regular intervals.
2876 The filter accepts the following options:
2880 Set the number of frames from which one will be dropped. Setting this to
2881 @var{N} means one frame in every batch of @var{N} frames will be dropped.
2882 Default is @code{5}.
2885 Set the threshold for duplicate detection. If the difference metric for a frame
2886 is less than or equal to this value, then it is declared as duplicate. Default
2890 Set scene change threshold. Default is @code{15}.
2894 Set the size of the x and y-axis blocks used during metric calculations.
2895 Larger blocks give better noise suppression, but also give worse detection of
2896 small movements. Must be a power of two. Default is @code{32}.
2899 Mark main input as a pre-processed input and activate clean source input
2900 stream. This allows the input to be pre-processed with various filters to help
2901 the metrics calculation while keeping the frame selection lossless. When set to
2902 @code{1}, the first stream is for the pre-processed input, and the second
2903 stream is the clean source from where the kept frames are chosen. Default is
2907 Set whether or not chroma is considered in the metric calculations. Default is
2913 Suppress a TV station logo by a simple interpolation of the surrounding
2914 pixels. Just set a rectangle covering the logo and watch it disappear
2915 (and sometimes something even uglier appear - your mileage may vary).
2917 This filter accepts the following options:
2922 Specify the top left corner coordinates of the logo. They must be
2927 Specify the width and height of the logo to clear. They must be
2931 Specify the thickness of the fuzzy edge of the rectangle (added to
2932 @var{w} and @var{h}). The default value is 4.
2935 When set to 1, a green rectangle is drawn on the screen to simplify
2936 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
2937 The default value is 0.
2939 The rectangle is drawn on the outermost pixels which will be (partly)
2940 replaced with interpolated values. The values of the next pixels
2941 immediately outside this rectangle in each direction will be used to
2942 compute the interpolated pixel values inside the rectangle.
2946 @subsection Examples
2950 Set a rectangle covering the area with top left corner coordinates 0,0
2951 and size 100x77, setting a band of size 10:
2953 delogo=x=0:y=0:w=100:h=77:band=10
2960 Attempt to fix small changes in horizontal and/or vertical shift. This
2961 filter helps remove camera shake from hand-holding a camera, bumping a
2962 tripod, moving on a vehicle, etc.
2964 The filter accepts the following options:
2972 Specify a rectangular area where to limit the search for motion
2974 If desired the search for motion vectors can be limited to a
2975 rectangular area of the frame defined by its top left corner, width
2976 and height. These parameters have the same meaning as the drawbox
2977 filter which can be used to visualise the position of the bounding
2980 This is useful when simultaneous movement of subjects within the frame
2981 might be confused for camera motion by the motion vector search.
2983 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
2984 then the full frame is used. This allows later options to be set
2985 without specifying the bounding box for the motion vector search.
2987 Default - search the whole frame.
2991 Specify the maximum extent of movement in x and y directions in the
2992 range 0-64 pixels. Default 16.
2995 Specify how to generate pixels to fill blanks at the edge of the
2996 frame. Available values are:
2999 Fill zeroes at blank locations
3001 Original image at blank locations
3003 Extruded edge value at blank locations
3005 Mirrored edge at blank locations
3007 Default value is @samp{mirror}.
3010 Specify the blocksize to use for motion search. Range 4-128 pixels,
3014 Specify the contrast threshold for blocks. Only blocks with more than
3015 the specified contrast (difference between darkest and lightest
3016 pixels) will be considered. Range 1-255, default 125.
3019 Specify the search strategy. Available values are:
3022 Set exhaustive search
3024 Set less exhaustive search.
3026 Default value is @samp{exhaustive}.
3029 If set then a detailed log of the motion search is written to the
3033 If set to 1, specify using OpenCL capabilities, only available if
3034 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3040 Draw a colored box on the input image.
3042 This filter accepts the following options:
3047 The expressions which specify the top left corner coordinates of the box. Default to 0.
3051 The expressions which specify the width and height of the box, if 0 they are interpreted as
3052 the input width and height. Default to 0.
3055 Specify the color of the box to write, it can be the name of a color
3056 (case insensitive match) or a 0xRRGGBB[AA] sequence. If the special
3057 value @code{invert} is used, the box edge color is the same as the
3058 video with inverted luma.
3061 The expression which sets the thickness of the box edge. Default value is @code{3}.
3063 See below for the list of accepted constants.
3066 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3067 following constants:
3071 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3075 horizontal and vertical chroma subsample values. For example for the
3076 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3080 The input width and height.
3083 The input sample aspect ratio.
3087 The x and y offset coordinates where the box is drawn.
3091 The width and height of the drawn box.
3094 The thickness of the drawn box.
3096 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3097 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3101 @subsection Examples
3105 Draw a black box around the edge of the input image:
3111 Draw a box with color red and an opacity of 50%:
3113 drawbox=10:20:200:60:red@@0.5
3116 The previous example can be specified as:
3118 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3122 Fill the box with pink color:
3124 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3128 Draw a 2-pixel red 2.40:1 mask:
3130 drawbox=x=-t:y=0.5*(ih-iw/2.4)-t:w=iw+t*2:h=iw/2.4+t*2:t=2:c=red
3136 Draw a grid on the input image.
3138 This filter accepts the following options:
3143 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3147 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3148 input width and height, respectively, minus @code{thickness}, so image gets
3149 framed. Default to 0.
3152 Specify the color of the grid, it can be the name of a color
3153 (case insensitive match) or a 0xRRGGBB[AA] sequence. If the special
3154 value @code{invert} is used, the grid color is the same as the
3155 video with inverted luma.
3156 Note that you can append opacity value (in range of 0.0 - 1.0)
3157 to color name after @@ sign.
3160 The expression which sets the thickness of the grid line. Default value is @code{1}.
3162 See below for the list of accepted constants.
3165 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3166 following constants:
3170 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3174 horizontal and vertical chroma subsample values. For example for the
3175 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3179 The input grid cell width and height.
3182 The input sample aspect ratio.
3186 The x and y coordinates of some point of grid intersection (meant to configure offset).
3190 The width and height of the drawn cell.
3193 The thickness of the drawn cell.
3195 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3196 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3200 @subsection Examples
3204 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3206 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3210 Draw a white 3x3 grid with an opacity of 50%:
3212 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3219 Draw text string or text from specified file on top of video using the
3220 libfreetype library.
3222 To enable compilation of this filter you need to configure FFmpeg with
3223 @code{--enable-libfreetype}.
3227 The description of the accepted parameters follows.
3232 Used to draw a box around text using background color.
3233 Value should be either 1 (enable) or 0 (disable).
3234 The default value of @var{box} is 0.
3237 The color to be used for drawing box around text.
3238 Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
3239 (e.g. "0xff00ff"), possibly followed by an alpha specifier.
3240 The default value of @var{boxcolor} is "white".
3243 Set an expression which specifies if the text should be drawn. If the
3244 expression evaluates to 0, the text is not drawn. This is useful for
3245 specifying that the text should be drawn only when specific conditions
3248 Default value is "1".
3250 See below for the list of accepted constants and functions.
3253 Select how the @var{text} is expanded. Can be either @code{none},
3254 @code{strftime} (deprecated) or
3255 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3259 If true, check and fix text coords to avoid clipping.
3262 The color to be used for drawing fonts.
3263 Either a string (e.g. "red") or in 0xRRGGBB[AA] format
3264 (e.g. "0xff000033"), possibly followed by an alpha specifier.
3265 The default value of @var{fontcolor} is "black".
3268 The font file to be used for drawing text. Path must be included.
3269 This parameter is mandatory.
3272 The font size to be used for drawing text.
3273 The default value of @var{fontsize} is 16.
3276 Flags to be used for loading the fonts.
3278 The flags map the corresponding flags supported by libfreetype, and are
3279 a combination of the following values:
3286 @item vertical_layout
3287 @item force_autohint
3290 @item ignore_global_advance_width
3292 @item ignore_transform
3298 Default value is "render".
3300 For more information consult the documentation for the FT_LOAD_*
3304 The color to be used for drawing a shadow behind the drawn text. It
3305 can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
3306 form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
3307 The default value of @var{shadowcolor} is "black".
3311 The x and y offsets for the text shadow position with respect to the
3312 position of the text. They can be either positive or negative
3313 values. Default value for both is "0".
3316 The starting frame number for the n/frame_num variable. The default value
3320 The size in number of spaces to use for rendering the tab.
3324 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3325 format. It can be used with or without text parameter. @var{timecode_rate}
3326 option must be specified.
3328 @item timecode_rate, rate, r
3329 Set the timecode frame rate (timecode only).
3332 The text string to be drawn. The text must be a sequence of UTF-8
3334 This parameter is mandatory if no file is specified with the parameter
3338 A text file containing text to be drawn. The text must be a sequence
3339 of UTF-8 encoded characters.
3341 This parameter is mandatory if no text string is specified with the
3342 parameter @var{text}.
3344 If both @var{text} and @var{textfile} are specified, an error is thrown.
3347 If set to 1, the @var{textfile} will be reloaded before each frame.
3348 Be sure to update it atomically, or it may be read partially, or even fail.
3352 The expressions which specify the offsets where text will be drawn
3353 within the video frame. They are relative to the top/left border of the
3356 The default value of @var{x} and @var{y} is "0".
3358 See below for the list of accepted constants and functions.
3361 The parameters for @var{x} and @var{y} are expressions containing the
3362 following constants and functions:
3366 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3370 horizontal and vertical chroma subsample values. For example for the
3371 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3374 the height of each text line
3382 @item max_glyph_a, ascent
3383 the maximum distance from the baseline to the highest/upper grid
3384 coordinate used to place a glyph outline point, for all the rendered
3386 It is a positive value, due to the grid's orientation with the Y axis
3389 @item max_glyph_d, descent
3390 the maximum distance from the baseline to the lowest grid coordinate
3391 used to place a glyph outline point, for all the rendered glyphs.
3392 This is a negative value, due to the grid's orientation, with the Y axis
3396 maximum glyph height, that is the maximum height for all the glyphs
3397 contained in the rendered text, it is equivalent to @var{ascent} -
3401 maximum glyph width, that is the maximum width for all the glyphs
3402 contained in the rendered text
3405 the number of input frame, starting from 0
3407 @item rand(min, max)
3408 return a random number included between @var{min} and @var{max}
3411 input sample aspect ratio
3414 timestamp expressed in seconds, NAN if the input timestamp is unknown
3417 the height of the rendered text
3420 the width of the rendered text
3424 the x and y offset coordinates where the text is drawn.
3426 These parameters allow the @var{x} and @var{y} expressions to refer
3427 each other, so you can for example specify @code{y=x/dar}.
3430 If libavfilter was built with @code{--enable-fontconfig}, then
3431 @option{fontfile} can be a fontconfig pattern or omitted.
3433 @anchor{drawtext_expansion}
3434 @subsection Text expansion
3436 If @option{expansion} is set to @code{strftime},
3437 the filter recognizes strftime() sequences in the provided text and
3438 expands them accordingly. Check the documentation of strftime(). This
3439 feature is deprecated.
3441 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3443 If @option{expansion} is set to @code{normal} (which is the default),
3444 the following expansion mechanism is used.
3446 The backslash character '\', followed by any character, always expands to
3447 the second character.
3449 Sequence of the form @code{%@{...@}} are expanded. The text between the
3450 braces is a function name, possibly followed by arguments separated by ':'.
3451 If the arguments contain special characters or delimiters (':' or '@}'),
3452 they should be escaped.
3454 Note that they probably must also be escaped as the value for the
3455 @option{text} option in the filter argument string and as the filter
3456 argument in the filtergraph description, and possibly also for the shell,
3457 that makes up to four levels of escaping; using a text file avoids these
3460 The following functions are available:
3465 The expression evaluation result.
3467 It must take one argument specifying the expression to be evaluated,
3468 which accepts the same constants and functions as the @var{x} and
3469 @var{y} values. Note that not all constants should be used, for
3470 example the text size is not known when evaluating the expression, so
3471 the constants @var{text_w} and @var{text_h} will have an undefined
3475 The time at which the filter is running, expressed in UTC.
3476 It can accept an argument: a strftime() format string.
3479 The time at which the filter is running, expressed in the local time zone.
3480 It can accept an argument: a strftime() format string.
3483 Frame metadata. It must take one argument specifying metadata key.
3486 The frame number, starting from 0.
3489 A 1 character description of the current picture type.
3492 The timestamp of the current frame, in seconds, with microsecond accuracy.
3496 @subsection Examples
3500 Draw "Test Text" with font FreeSerif, using the default values for the
3501 optional parameters.
3504 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
3508 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
3509 and y=50 (counting from the top-left corner of the screen), text is
3510 yellow with a red box around it. Both the text and the box have an
3514 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
3515 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
3518 Note that the double quotes are not necessary if spaces are not used
3519 within the parameter list.
3522 Show the text at the center of the video frame:
3524 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
3528 Show a text line sliding from right to left in the last row of the video
3529 frame. The file @file{LONG_LINE} is assumed to contain a single line
3532 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
3536 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
3538 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
3542 Draw a single green letter "g", at the center of the input video.
3543 The glyph baseline is placed at half screen height.
3545 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
3549 Show text for 1 second every 3 seconds:
3551 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:draw=lt(mod(t\,3)\,1):text='blink'"
3555 Use fontconfig to set the font. Note that the colons need to be escaped.
3557 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
3561 Print the date of a real-time encoding (see strftime(3)):
3563 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
3568 For more information about libfreetype, check:
3569 @url{http://www.freetype.org/}.
3571 For more information about fontconfig, check:
3572 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
3576 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
3578 The filter accepts the following options:
3583 Set low and high threshold values used by the Canny thresholding
3586 The high threshold selects the "strong" edge pixels, which are then
3587 connected through 8-connectivity with the "weak" edge pixels selected
3588 by the low threshold.
3590 @var{low} and @var{high} threshold values must be choosen in the range
3591 [0,1], and @var{low} should be lesser or equal to @var{high}.
3593 Default value for @var{low} is @code{20/255}, and default value for @var{high}
3599 edgedetect=low=0.1:high=0.4
3602 @section extractplanes
3604 Extract color channel components from input video stream into
3605 separate grayscale video streams.
3607 The filter accepts the following option:
3611 Set plane(s) to extract.
3613 Available values for planes are:
3624 Choosing planes not available in the input will result in an error.
3625 That means you cannot select @code{r}, @code{g}, @code{b} planes
3626 with @code{y}, @code{u}, @code{v} planes at same time.
3629 @subsection Examples
3633 Extract luma, u and v color channel component from input video frame
3634 into 3 grayscale outputs:
3636 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
3642 Apply fade-in/out effect to input video.
3644 This filter accepts the following options:
3648 The effect type -- can be either "in" for fade-in, or "out" for a fade-out
3650 Default is @code{in}.
3652 @item start_frame, s
3653 Specify the number of the start frame for starting to apply the fade
3654 effect. Default is 0.
3657 The number of frames for which the fade effect has to last. At the end of the
3658 fade-in effect the output video will have the same intensity as the input video,
3659 at the end of the fade-out transition the output video will be completely black.
3663 If set to 1, fade only alpha channel, if one exists on the input.
3666 @item start_time, st
3667 Specify the timestamp (in seconds) of the frame to start to apply the fade
3668 effect. If both start_frame and start_time are specified, the fade will start at
3669 whichever comes last. Default is 0.
3672 The number of seconds for which the fade effect has to last. At the end of the
3673 fade-in effect the output video will have the same intensity as the input video,
3674 at the end of the fade-out transition the output video will be completely black.
3675 If both duration and nb_frames are specified, duration is used. Default is 0.
3678 @subsection Examples
3682 Fade in first 30 frames of video:
3687 The command above is equivalent to:
3693 Fade out last 45 frames of a 200-frame video:
3696 fade=type=out:start_frame=155:nb_frames=45
3700 Fade in first 25 frames and fade out last 25 frames of a 1000-frame video:
3702 fade=in:0:25, fade=out:975:25
3706 Make first 5 frames black, then fade in from frame 5-24:
3712 Fade in alpha over first 25 frames of video:
3714 fade=in:0:25:alpha=1
3718 Make first 5.5 seconds black, then fade in for 0.5 seconds:
3720 fade=t=in:st=5.5:d=0.5
3727 Extract a single field from an interlaced image using stride
3728 arithmetic to avoid wasting CPU time. The output frames are marked as
3731 The filter accepts the following options:
3735 Specify whether to extract the top (if the value is @code{0} or
3736 @code{top}) or the bottom field (if the value is @code{1} or
3742 Field matching filter for inverse telecine. It is meant to reconstruct the
3743 progressive frames from a telecined stream. The filter does not drop duplicated
3744 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
3745 followed by a decimation filter such as @ref{decimate} in the filtergraph.
3747 The separation of the field matching and the decimation is notably motivated by
3748 the possibility of inserting a de-interlacing filter fallback between the two.
3749 If the source has mixed telecined and real interlaced content,
3750 @code{fieldmatch} will not be able to match fields for the interlaced parts.
3751 But these remaining combed frames will be marked as interlaced, and thus can be
3752 de-interlaced by a later filter such as @ref{yadif} before decimation.
3754 In addition to the various configuration options, @code{fieldmatch} can take an
3755 optional second stream, activated through the @option{ppsrc} option. If
3756 enabled, the frames reconstruction will be based on the fields and frames from
3757 this second stream. This allows the first input to be pre-processed in order to
3758 help the various algorithms of the filter, while keeping the output lossless
3759 (assuming the fields are matched properly). Typically, a field-aware denoiser,
3760 or brightness/contrast adjustments can help.
3762 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
3763 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
3764 which @code{fieldmatch} is based on. While the semantic and usage are very
3765 close, some behaviour and options names can differ.
3767 The filter accepts the following options:
3771 Specify the assumed field order of the input stream. Available values are:
3775 Auto detect parity (use FFmpeg's internal parity value).
3777 Assume bottom field first.
3779 Assume top field first.
3782 Note that it is sometimes recommended not to trust the parity announced by the
3785 Default value is @var{auto}.
3788 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
3789 sense that it won't risk creating jerkiness due to duplicate frames when
3790 possible, but if there are bad edits or blended fields it will end up
3791 outputting combed frames when a good match might actually exist. On the other
3792 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
3793 but will almost always find a good frame if there is one. The other values are
3794 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
3795 jerkiness and creating duplicate frames versus finding good matches in sections
3796 with bad edits, orphaned fields, blended fields, etc.
3798 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
3800 Available values are:
3804 2-way matching (p/c)
3806 2-way matching, and trying 3rd match if still combed (p/c + n)
3808 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
3810 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
3811 still combed (p/c + n + u/b)
3813 3-way matching (p/c/n)
3815 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
3816 detected as combed (p/c/n + u/b)
3819 The parenthesis at the end indicate the matches that would be used for that
3820 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
3823 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
3826 Default value is @var{pc_n}.
3829 Mark the main input stream as a pre-processed input, and enable the secondary
3830 input stream as the clean source to pick the fields from. See the filter
3831 introduction for more details. It is similar to the @option{clip2} feature from
3834 Default value is @code{0} (disabled).
3837 Set the field to match from. It is recommended to set this to the same value as
3838 @option{order} unless you experience matching failures with that setting. In
3839 certain circumstances changing the field that is used to match from can have a
3840 large impact on matching performance. Available values are:
3844 Automatic (same value as @option{order}).
3846 Match from the bottom field.
3848 Match from the top field.
3851 Default value is @var{auto}.
3854 Set whether or not chroma is included during the match comparisons. In most
3855 cases it is recommended to leave this enabled. You should set this to @code{0}
3856 only if your clip has bad chroma problems such as heavy rainbowing or other
3857 artifacts. Setting this to @code{0} could also be used to speed things up at
3858 the cost of some accuracy.
3860 Default value is @code{1}.
3864 These define an exclusion band which excludes the lines between @option{y0} and
3865 @option{y1} from being included in the field matching decision. An exclusion
3866 band can be used to ignore subtitles, a logo, or other things that may
3867 interfere with the matching. @option{y0} sets the starting scan line and
3868 @option{y1} sets the ending line; all lines in between @option{y0} and
3869 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
3870 @option{y0} and @option{y1} to the same value will disable the feature.
3871 @option{y0} and @option{y1} defaults to @code{0}.
3874 Set the scene change detection threshold as a percentage of maximum change on
3875 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
3876 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
3877 @option{scthresh} is @code{[0.0, 100.0]}.
3879 Default value is @code{12.0}.
3882 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
3883 account the combed scores of matches when deciding what match to use as the
3884 final match. Available values are:
3888 No final matching based on combed scores.
3890 Combed scores are only used when a scene change is detected.
3892 Use combed scores all the time.
3895 Default is @var{sc}.
3898 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
3899 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
3900 Available values are:
3904 No forced calculation.
3906 Force p/c/n calculations.
3908 Force p/c/n/u/b calculations.
3911 Default value is @var{none}.
3914 This is the area combing threshold used for combed frame detection. This
3915 essentially controls how "strong" or "visible" combing must be to be detected.
3916 Larger values mean combing must be more visible and smaller values mean combing
3917 can be less visible or strong and still be detected. Valid settings are from
3918 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
3919 be detected as combed). This is basically a pixel difference value. A good
3920 range is @code{[8, 12]}.
3922 Default value is @code{9}.
3925 Sets whether or not chroma is considered in the combed frame decision. Only
3926 disable this if your source has chroma problems (rainbowing, etc.) that are
3927 causing problems for the combed frame detection with chroma enabled. Actually,
3928 using @option{chroma}=@var{0} is usually more reliable, except for the case
3929 where there is chroma only combing in the source.
3931 Default value is @code{0}.
3935 Respectively set the x-axis and y-axis size of the window used during combed
3936 frame detection. This has to do with the size of the area in which
3937 @option{combpel} pixels are required to be detected as combed for a frame to be
3938 declared combed. See the @option{combpel} parameter description for more info.
3939 Possible values are any number that is a power of 2 starting at 4 and going up
3942 Default value is @code{16}.
3945 The number of combed pixels inside any of the @option{blocky} by
3946 @option{blockx} size blocks on the frame for the frame to be detected as
3947 combed. While @option{cthresh} controls how "visible" the combing must be, this
3948 setting controls "how much" combing there must be in any localized area (a
3949 window defined by the @option{blockx} and @option{blocky} settings) on the
3950 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
3951 which point no frames will ever be detected as combed). This setting is known
3952 as @option{MI} in TFM/VFM vocabulary.
3954 Default value is @code{80}.
3957 @anchor{p/c/n/u/b meaning}
3958 @subsection p/c/n/u/b meaning
3960 @subsubsection p/c/n
3962 We assume the following telecined stream:
3965 Top fields: 1 2 2 3 4
3966 Bottom fields: 1 2 3 4 4
3969 The numbers correspond to the progressive frame the fields relate to. Here, the
3970 first two frames are progressive, the 3rd and 4th are combed, and so on.
3972 When @code{fieldmatch} is configured to run a matching from bottom
3973 (@option{field}=@var{bottom}) this is how this input stream get transformed:
3978 B 1 2 3 4 4 <-- matching reference
3987 As a result of the field matching, we can see that some frames get duplicated.
3988 To perform a complete inverse telecine, you need to rely on a decimation filter
3989 after this operation. See for instance the @ref{decimate} filter.
3991 The same operation now matching from top fields (@option{field}=@var{top})
3996 T 1 2 2 3 4 <-- matching reference
4006 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4007 basically, they refer to the frame and field of the opposite parity:
4010 @item @var{p} matches the field of the opposite parity in the previous frame
4011 @item @var{c} matches the field of the opposite parity in the current frame
4012 @item @var{n} matches the field of the opposite parity in the next frame
4017 The @var{u} and @var{b} matching are a bit special in the sense that they match
4018 from the opposite parity flag. In the following examples, we assume that we are
4019 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4020 'x' is placed above and below each matched fields.
4022 With bottom matching (@option{field}=@var{bottom}):
4027 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4028 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4036 With top matching (@option{field}=@var{top}):
4041 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4042 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4050 @subsection Examples
4052 Simple IVTC of a top field first telecined stream:
4054 fieldmatch=order=tff:combmatch=none, decimate
4057 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4059 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4064 Transform the field order of the input video.
4066 This filter accepts the following options:
4071 Output field order. Valid values are @var{tff} for top field first or @var{bff}
4072 for bottom field first.
4075 Default value is @samp{tff}.
4077 Transformation is achieved by shifting the picture content up or down
4078 by one line, and filling the remaining line with appropriate picture content.
4079 This method is consistent with most broadcast field order converters.
4081 If the input video is not flagged as being interlaced, or it is already
4082 flagged as being of the required output field order then this filter does
4083 not alter the incoming video.
4085 This filter is very useful when converting to or from PAL DV material,
4086 which is bottom field first.
4090 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4095 Buffer input images and send them when they are requested.
4097 This filter is mainly useful when auto-inserted by the libavfilter
4100 The filter does not take parameters.
4105 Convert the input video to one of the specified pixel formats.
4106 Libavfilter will try to pick one that is supported for the input to
4109 This filter accepts the following parameters:
4113 A '|'-separated list of pixel format names, for example
4114 "pix_fmts=yuv420p|monow|rgb24".
4118 @subsection Examples
4122 Convert the input video to the format @var{yuv420p}
4124 format=pix_fmts=yuv420p
4127 Convert the input video to any of the formats in the list
4129 format=pix_fmts=yuv420p|yuv444p|yuv410p
4135 Convert the video to specified constant frame rate by duplicating or dropping
4136 frames as necessary.
4138 This filter accepts the following named parameters:
4142 Desired output frame rate. The default is @code{25}.
4147 Possible values are:
4150 zero round towards 0
4154 round towards -infinity
4156 round towards +infinity
4160 The default is @code{near}.
4163 Assume the first PTS should be the given value, in seconds. This allows for
4164 padding/trimming at the start of stream. By default, no assumption is made
4165 about the first frame's expected PTS, so no padding or trimming is done.
4166 For example, this could be set to 0 to pad the beginning with duplicates of
4167 the first frame if a video stream starts after the audio stream or to trim any
4168 frames with a negative PTS.
4172 Alternatively, the options can be specified as a flat string:
4173 @var{fps}[:@var{round}].
4175 See also the @ref{setpts} filter.
4177 @subsection Examples
4181 A typical usage in order to set the fps to 25:
4187 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4189 fps=fps=film:round=near
4195 Select one frame every N-th frame.
4197 This filter accepts the following option:
4200 Select frame after every @code{step} frames.
4201 Allowed values are positive integers higher than 0. Default value is @code{1}.
4207 Apply a frei0r effect to the input video.
4209 To enable compilation of this filter you need to install the frei0r
4210 header and configure FFmpeg with @code{--enable-frei0r}.
4212 This filter accepts the following options:
4217 The name to the frei0r effect to load. If the environment variable
4218 @env{FREI0R_PATH} is defined, the frei0r effect is searched in each one of the
4219 directories specified by the colon separated list in @env{FREIOR_PATH},
4220 otherwise in the standard frei0r paths, which are in this order:
4221 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
4222 @file{/usr/lib/frei0r-1/}.
4225 A '|'-separated list of parameters to pass to the frei0r effect.
4229 A frei0r effect parameter can be a boolean (whose values are specified
4230 with "y" and "n"), a double, a color (specified by the syntax
4231 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
4232 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
4233 description), a position (specified by the syntax @var{X}/@var{Y},
4234 @var{X} and @var{Y} being float numbers) and a string.
4236 The number and kind of parameters depend on the loaded effect. If an
4237 effect parameter is not specified the default value is set.
4239 @subsection Examples
4243 Apply the distort0r effect, set the first two double parameters:
4245 frei0r=filter_name=distort0r:filter_params=0.5|0.01
4249 Apply the colordistance effect, take a color as first parameter:
4251 frei0r=colordistance:0.2/0.3/0.4
4252 frei0r=colordistance:violet
4253 frei0r=colordistance:0x112233
4257 Apply the perspective effect, specify the top left and top right image
4260 frei0r=perspective:0.2/0.2|0.8/0.2
4264 For more information see:
4265 @url{http://frei0r.dyne.org}
4269 The filter accepts the following options:
4273 Set the luminance expression.
4275 Set the chrominance blue expression.
4277 Set the chrominance red expression.
4279 Set the alpha expression.
4281 Set the red expression.
4283 Set the green expression.
4285 Set the blue expression.
4288 The colorspace is selected according to the specified options. If one
4289 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4290 options is specified, the filter will automatically select a YCbCr
4291 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4292 @option{blue_expr} options is specified, it will select an RGB
4295 If one of the chrominance expression is not defined, it falls back on the other
4296 one. If no alpha expression is specified it will evaluate to opaque value.
4297 If none of chrominance expressions are specified, they will evaluate
4298 to the luminance expression.
4300 The expressions can use the following variables and functions:
4304 The sequential number of the filtered frame, starting from @code{0}.
4308 The coordinates of the current sample.
4312 The width and height of the image.
4316 Width and height scale depending on the currently filtered plane. It is the
4317 ratio between the corresponding luma plane number of pixels and the current
4318 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4319 @code{0.5,0.5} for chroma planes.
4322 Time of the current frame, expressed in seconds.
4325 Return the value of the pixel at location (@var{x},@var{y}) of the current
4329 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
4333 Return the value of the pixel at location (@var{x},@var{y}) of the
4334 blue-difference chroma plane. Return 0 if there is no such plane.
4337 Return the value of the pixel at location (@var{x},@var{y}) of the
4338 red-difference chroma plane. Return 0 if there is no such plane.
4343 Return the value of the pixel at location (@var{x},@var{y}) of the
4344 red/green/blue component. Return 0 if there is no such component.
4347 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
4348 plane. Return 0 if there is no such plane.
4351 For functions, if @var{x} and @var{y} are outside the area, the value will be
4352 automatically clipped to the closer edge.
4354 @subsection Examples
4358 Flip the image horizontally:
4364 Generate a bidimensional sine wave, with angle @code{PI/3} and a
4365 wavelength of 100 pixels:
4367 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
4371 Generate a fancy enigmatic moving light:
4373 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
4377 Generate a quick emboss effect:
4379 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
4383 Modify RGB components depending on pixel position:
4385 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
4391 Fix the banding artifacts that are sometimes introduced into nearly flat
4392 regions by truncation to 8bit color depth.
4393 Interpolate the gradients that should go where the bands are, and
4396 This filter is designed for playback only. Do not use it prior to
4397 lossy compression, because compression tends to lose the dither and
4398 bring back the bands.
4400 This filter accepts the following options:
4405 The maximum amount by which the filter will change any one pixel. Also the
4406 threshold for detecting nearly flat regions. Acceptable values range from .51 to
4407 64, default value is 1.2, out-of-range values will be clipped to the valid
4411 The neighborhood to fit the gradient to. A larger radius makes for smoother
4412 gradients, but also prevents the filter from modifying the pixels near detailed
4413 regions. Acceptable values are 8-32, default value is 16, out-of-range values
4414 will be clipped to the valid range.
4418 Alternatively, the options can be specified as a flat string:
4419 @var{strength}[:@var{radius}]
4421 @subsection Examples
4425 Apply the filter with a @code{3.5} strength and radius of @code{8}:
4431 Specify radius, omitting the strength (which will fall-back to the default
4442 Apply a Hald CLUT to a video stream.
4444 First input is the video stream to process, and second one is the Hald CLUT.
4445 The Hald CLUT input can be a simple picture or a complete video stream.
4447 The filter accepts the following options:
4451 Force termination when the shortest input terminates. Default is @code{0}.
4453 Continue applying the last CLUT after the end of the stream. A value of
4454 @code{0} disable the filter after the last frame of the CLUT is reached.
4455 Default is @code{1}.
4458 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
4459 filters share the same internals).
4461 More information about the Hald CLUT can be found on Eskil Steenberg's website
4462 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
4464 @subsection Workflow examples
4466 @subsubsection Hald CLUT video stream
4468 Generate an identity Hald CLUT stream altered with various effects:
4470 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
4473 Note: make sure you use a lossless codec.
4475 Then use it with @code{haldclut} to apply it on some random stream:
4477 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
4480 The Hald CLUT will be applied to the 10 first seconds (duration of
4481 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
4482 to the remaining frames of the @code{mandelbrot} stream.
4484 @subsubsection Hald CLUT with preview
4486 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
4487 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
4488 biggest possible square starting at the top left of the picture. The remaining
4489 padding pixels (bottom or right) will be ignored. This area can be used to add
4490 a preview of the Hald CLUT.
4492 Typically, the following generated Hald CLUT will be supported by the
4493 @code{haldclut} filter:
4496 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
4497 pad=iw+320 [padded_clut];
4498 smptebars=s=320x256, split [a][b];
4499 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
4500 [main][b] overlay=W-320" -frames:v 1 clut.png
4503 It contains the original and a preview of the effect of the CLUT: SMPTE color
4504 bars are displayed on the right-top, and below the same color bars processed by
4507 Then, the effect of this Hald CLUT can be visualized with:
4509 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
4514 Flip the input video horizontally.
4516 For example to horizontally flip the input video with @command{ffmpeg}:
4518 ffmpeg -i in.avi -vf "hflip" out.avi
4522 This filter applies a global color histogram equalization on a
4525 It can be used to correct video that has a compressed range of pixel
4526 intensities. The filter redistributes the pixel intensities to
4527 equalize their distribution across the intensity range. It may be
4528 viewed as an "automatically adjusting contrast filter". This filter is
4529 useful only for correcting degraded or poorly captured source
4532 The filter accepts the following options:
4536 Determine the amount of equalization to be applied. As the strength
4537 is reduced, the distribution of pixel intensities more-and-more
4538 approaches that of the input frame. The value must be a float number
4539 in the range [0,1] and defaults to 0.200.
4542 Set the maximum intensity that can generated and scale the output
4543 values appropriately. The strength should be set as desired and then
4544 the intensity can be limited if needed to avoid washing-out. The value
4545 must be a float number in the range [0,1] and defaults to 0.210.
4548 Set the antibanding level. If enabled the filter will randomly vary
4549 the luminance of output pixels by a small amount to avoid banding of
4550 the histogram. Possible values are @code{none}, @code{weak} or
4551 @code{strong}. It defaults to @code{none}.
4556 Compute and draw a color distribution histogram for the input video.
4558 The computed histogram is a representation of distribution of color components
4561 The filter accepts the following options:
4567 It accepts the following values:
4570 standard histogram that display color components distribution in an image.
4571 Displays color graph for each color component. Shows distribution
4572 of the Y, U, V, A or G, B, R components, depending on input format,
4573 in current frame. Bellow each graph is color component scale meter.
4576 chroma values in vectorscope, if brighter more such chroma values are
4577 distributed in an image.
4578 Displays chroma values (U/V color placement) in two dimensional graph
4579 (which is called a vectorscope). It can be used to read of the hue and
4580 saturation of the current frame. At a same time it is a histogram.
4581 The whiter a pixel in the vectorscope, the more pixels of the input frame
4582 correspond to that pixel (that is the more pixels have this chroma value).
4583 The V component is displayed on the horizontal (X) axis, with the leftmost
4584 side being V = 0 and the rightmost side being V = 255.
4585 The U component is displayed on the vertical (Y) axis, with the top
4586 representing U = 0 and the bottom representing U = 255.
4588 The position of a white pixel in the graph corresponds to the chroma value
4589 of a pixel of the input clip. So the graph can be used to read of the
4590 hue (color flavor) and the saturation (the dominance of the hue in the color).
4591 As the hue of a color changes, it moves around the square. At the center of
4592 the square, the saturation is zero, which means that the corresponding pixel
4593 has no color. If you increase the amount of a specific color, while leaving
4594 the other colors unchanged, the saturation increases, and you move towards
4595 the edge of the square.
4598 chroma values in vectorscope, similar as @code{color} but actual chroma values
4602 per row/column color component graph. In row mode graph in the left side represents
4603 color component value 0 and right side represents value = 255. In column mode top
4604 side represents color component value = 0 and bottom side represents value = 255.
4606 Default value is @code{levels}.
4609 Set height of level in @code{levels}. Default value is @code{200}.
4610 Allowed range is [50, 2048].
4613 Set height of color scale in @code{levels}. Default value is @code{12}.
4614 Allowed range is [0, 40].
4617 Set step for @code{waveform} mode. Smaller values are useful to find out how much
4618 of same luminance values across input rows/columns are distributed.
4619 Default value is @code{10}. Allowed range is [1, 255].
4622 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
4623 Default is @code{row}.
4626 Set display mode for @code{waveform} and @code{levels}.
4627 It accepts the following values:
4630 Display separate graph for the color components side by side in
4631 @code{row} waveform mode or one below other in @code{column} waveform mode
4632 for @code{waveform} histogram mode. For @code{levels} histogram mode
4633 per color component graphs are placed one bellow other.
4635 This display mode in @code{waveform} histogram mode makes it easy to spot
4636 color casts in the highlights and shadows of an image, by comparing the
4637 contours of the top and the bottom of each waveform.
4638 Since whites, grays, and blacks are characterized by
4639 exactly equal amounts of red, green, and blue, neutral areas of the
4640 picture should display three waveforms of roughly equal width/height.
4641 If not, the correction is easy to make by making adjustments to level the
4645 Presents information that's identical to that in the @code{parade}, except
4646 that the graphs representing color components are superimposed directly
4649 This display mode in @code{waveform} histogram mode can make it easier to spot
4650 the relative differences or similarities in overlapping areas of the color
4651 components that are supposed to be identical, such as neutral whites, grays,
4654 Default is @code{parade}.
4657 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
4658 Default is @code{linear}.
4661 @subsection Examples
4666 Calculate and draw histogram:
4668 ffplay -i input -vf histogram
4676 High precision/quality 3d denoise filter. This filter aims to reduce
4677 image noise producing smooth images and making still images really
4678 still. It should enhance compressibility.
4680 It accepts the following optional parameters:
4684 a non-negative float number which specifies spatial luma strength,
4687 @item chroma_spatial
4688 a non-negative float number which specifies spatial chroma strength,
4689 defaults to 3.0*@var{luma_spatial}/4.0
4692 a float number which specifies luma temporal strength, defaults to
4693 6.0*@var{luma_spatial}/4.0
4696 a float number which specifies chroma temporal strength, defaults to
4697 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
4702 Modify the hue and/or the saturation of the input.
4704 This filter accepts the following options:
4708 Specify the hue angle as a number of degrees. It accepts an expression,
4709 and defaults to "0".
4712 Specify the saturation in the [-10,10] range. It accepts an expression and
4716 Specify the hue angle as a number of radians. It accepts an
4717 expression, and defaults to "0".
4720 Specify the brightness in the [-10,10] range. It accepts an expression and
4724 @option{h} and @option{H} are mutually exclusive, and can't be
4725 specified at the same time.
4727 The @option{b}, @option{h}, @option{H} and @option{s} option values are
4728 expressions containing the following constants:
4732 frame count of the input frame starting from 0
4735 presentation timestamp of the input frame expressed in time base units
4738 frame rate of the input video, NAN if the input frame rate is unknown
4741 timestamp expressed in seconds, NAN if the input timestamp is unknown
4744 time base of the input video
4747 @subsection Examples
4751 Set the hue to 90 degrees and the saturation to 1.0:
4757 Same command but expressing the hue in radians:
4763 Rotate hue and make the saturation swing between 0
4764 and 2 over a period of 1 second:
4766 hue="H=2*PI*t: s=sin(2*PI*t)+1"
4770 Apply a 3 seconds saturation fade-in effect starting at 0:
4775 The general fade-in expression can be written as:
4777 hue="s=min(0\, max((t-START)/DURATION\, 1))"
4781 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
4783 hue="s=max(0\, min(1\, (8-t)/3))"
4786 The general fade-out expression can be written as:
4788 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
4793 @subsection Commands
4795 This filter supports the following commands:
4801 Modify the hue and/or the saturation and/or brightness of the input video.
4802 The command accepts the same syntax of the corresponding option.
4804 If the specified expression is not valid, it is kept at its current
4810 Detect video interlacing type.
4812 This filter tries to detect if the input is interlaced or progressive,
4813 top or bottom field first.
4815 The filter accepts the following options:
4819 Set interlacing threshold.
4821 Set progressive threshold.
4826 Deinterleave or interleave fields.
4828 This filter allows to process interlaced images fields without
4829 deinterlacing them. Deinterleaving splits the input frame into 2
4830 fields (so called half pictures). Odd lines are moved to the top
4831 half of the output image, even lines to the bottom half.
4832 You can process (filter) them independently and then re-interleave them.
4834 The filter accepts the following options:
4838 @item chroma_mode, c
4840 Available values for @var{luma_mode}, @var{chroma_mode} and
4841 @var{alpha_mode} are:
4847 @item deinterleave, d
4848 Deinterleave fields, placing one above the other.
4851 Interleave fields. Reverse the effect of deinterleaving.
4853 Default value is @code{none}.
4856 @item chroma_swap, cs
4857 @item alpha_swap, as
4858 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
4863 Simple interlacing filter from progressive contents. This interleaves upper (or
4864 lower) lines from odd frames with lower (or upper) lines from even frames,
4865 halving the frame rate and preserving image height.
4868 Original Original New Frame
4869 Frame 'j' Frame 'j+1' (tff)
4870 ========== =========== ==================
4871 Line 0 --------------------> Frame 'j' Line 0
4872 Line 1 Line 1 ----> Frame 'j+1' Line 1
4873 Line 2 ---------------------> Frame 'j' Line 2
4874 Line 3 Line 3 ----> Frame 'j+1' Line 3
4876 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
4879 It accepts the following optional parameters:
4883 determines whether the interlaced frame is taken from the even (tff - default)
4884 or odd (bff) lines of the progressive frame.
4887 Enable (default) or disable the vertical lowpass filter to avoid twitter
4888 interlacing and reduce moire patterns.
4893 Deinterlace input video by applying Donald Graft's adaptive kernel
4894 deinterling. Work on interlaced parts of a video to produce
4897 The description of the accepted parameters follows.
4901 Set the threshold which affects the filter's tolerance when
4902 determining if a pixel line must be processed. It must be an integer
4903 in the range [0,255] and defaults to 10. A value of 0 will result in
4904 applying the process on every pixels.
4907 Paint pixels exceeding the threshold value to white if set to 1.
4911 Set the fields order. Swap fields if set to 1, leave fields alone if
4915 Enable additional sharpening if set to 1. Default is 0.
4918 Enable twoway sharpening if set to 1. Default is 0.
4921 @subsection Examples
4925 Apply default values:
4927 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
4931 Enable additional sharpening:
4937 Paint processed pixels in white:
4946 Apply a 3D LUT to an input video.
4948 The filter accepts the following options:
4952 Set the 3D LUT file name.
4954 Currently supported formats:
4966 Select interpolation mode.
4968 Available values are:
4972 Use values from the nearest defined point.
4974 Interpolate values using the 8 points defining a cube.
4976 Interpolate values using a tetrahedron.
4980 @section lut, lutrgb, lutyuv
4982 Compute a look-up table for binding each pixel component input value
4983 to an output value, and apply it to input video.
4985 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
4986 to an RGB input video.
4988 These filters accept the following options:
4991 set first pixel component expression
4993 set second pixel component expression
4995 set third pixel component expression
4997 set fourth pixel component expression, corresponds to the alpha component
5000 set red component expression
5002 set green component expression
5004 set blue component expression
5006 alpha component expression
5009 set Y/luminance component expression
5011 set U/Cb component expression
5013 set V/Cr component expression
5016 Each of them specifies the expression to use for computing the lookup table for
5017 the corresponding pixel component values.
5019 The exact component associated to each of the @var{c*} options depends on the
5022 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5023 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5025 The expressions can contain the following constants and functions:
5030 the input width and height
5033 input value for the pixel component
5036 the input value clipped in the @var{minval}-@var{maxval} range
5039 maximum value for the pixel component
5042 minimum value for the pixel component
5045 the negated value for the pixel component value clipped in the
5046 @var{minval}-@var{maxval} range , it corresponds to the expression
5047 "maxval-clipval+minval"
5050 the computed value in @var{val} clipped in the
5051 @var{minval}-@var{maxval} range
5053 @item gammaval(gamma)
5054 the computed gamma correction value of the pixel component value
5055 clipped in the @var{minval}-@var{maxval} range, corresponds to the
5057 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
5061 All expressions default to "val".
5063 @subsection Examples
5069 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
5070 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
5073 The above is the same as:
5075 lutrgb="r=negval:g=negval:b=negval"
5076 lutyuv="y=negval:u=negval:v=negval"
5086 Remove chroma components, turns the video into a graytone image:
5088 lutyuv="u=128:v=128"
5092 Apply a luma burning effect:
5098 Remove green and blue components:
5104 Set a constant alpha channel value on input:
5106 format=rgba,lutrgb=a="maxval-minval/2"
5110 Correct luminance gamma by a 0.5 factor:
5112 lutyuv=y=gammaval(0.5)
5116 Discard least significant bits of luma:
5118 lutyuv=y='bitand(val, 128+64+32)'
5124 Apply motion-compensation deinterlacing.
5126 It needs one field per frame as input and must thus be used together
5127 with yadif=1/3 or equivalent.
5129 This filter accepts the following options:
5132 Set the deinterlacing mode.
5134 It accepts one of the following values:
5139 use iterative motion estimation
5141 like @samp{slow}, but use multiple reference frames.
5143 Default value is @samp{fast}.
5146 Set the picture field parity assumed for the input video. It must be
5147 one of the following values:
5151 assume top field first
5153 assume bottom field first
5156 Default value is @samp{bff}.
5159 Set per-block quantization parameter (QP) used by the internal
5162 Higher values should result in a smoother motion vector field but less
5163 optimal individual vectors. Default value is 1.
5168 Apply an MPlayer filter to the input video.
5170 This filter provides a wrapper around some of the filters of
5173 This wrapper is considered experimental. Some of the wrapped filters
5174 may not work properly and we may drop support for them, as they will
5175 be implemented natively into FFmpeg. Thus you should avoid
5176 depending on them when writing portable scripts.
5178 The filter accepts the parameters:
5179 @var{filter_name}[:=]@var{filter_params}
5181 @var{filter_name} is the name of a supported MPlayer filter,
5182 @var{filter_params} is a string containing the parameters accepted by
5185 The list of the currently supported filters follows:
5201 The parameter syntax and behavior for the listed filters are the same
5202 of the corresponding MPlayer filters. For detailed instructions check
5203 the "VIDEO FILTERS" section in the MPlayer manual.
5205 @subsection Examples
5209 Adjust gamma, brightness, contrast:
5215 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
5219 Drop frames that do not differ greatly from the previous frame in
5220 order to reduce frame rate.
5222 The main use of this filter is for very-low-bitrate encoding
5223 (e.g. streaming over dialup modem), but it could in theory be used for
5224 fixing movies that were inverse-telecined incorrectly.
5226 A description of the accepted options follows.
5230 Set the maximum number of consecutive frames which can be dropped (if
5231 positive), or the minimum interval between dropped frames (if
5232 negative). If the value is 0, the frame is dropped unregarding the
5233 number of previous sequentially dropped frames.
5240 Set the dropping threshold values.
5242 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
5243 represent actual pixel value differences, so a threshold of 64
5244 corresponds to 1 unit of difference for each pixel, or the same spread
5245 out differently over the block.
5247 A frame is a candidate for dropping if no 8x8 blocks differ by more
5248 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
5249 meaning the whole image) differ by more than a threshold of @option{lo}.
5251 Default value for @option{hi} is 64*12, default value for @option{lo} is
5252 64*5, and default value for @option{frac} is 0.33.
5260 This filter accepts an integer in input, if non-zero it negates the
5261 alpha component (if available). The default value in input is 0.
5265 Force libavfilter not to use any of the specified pixel formats for the
5266 input to the next filter.
5268 This filter accepts the following parameters:
5272 A '|'-separated list of pixel format names, for example
5273 "pix_fmts=yuv420p|monow|rgb24".
5277 @subsection Examples
5281 Force libavfilter to use a format different from @var{yuv420p} for the
5282 input to the vflip filter:
5284 noformat=pix_fmts=yuv420p,vflip
5288 Convert the input video to any of the formats not contained in the list:
5290 noformat=yuv420p|yuv444p|yuv410p
5296 Add noise on video input frame.
5298 The filter accepts the following options:
5306 Set noise seed for specific pixel component or all pixel components in case
5307 of @var{all_seed}. Default value is @code{123457}.
5309 @item all_strength, alls
5310 @item c0_strength, c0s
5311 @item c1_strength, c1s
5312 @item c2_strength, c2s
5313 @item c3_strength, c3s
5314 Set noise strength for specific pixel component or all pixel components in case
5315 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
5317 @item all_flags, allf
5322 Set pixel component flags or set flags for all components if @var{all_flags}.
5323 Available values for component flags are:
5326 averaged temporal noise (smoother)
5328 mix random noise with a (semi)regular pattern
5330 temporal noise (noise pattern changes between frames)
5332 uniform noise (gaussian otherwise)
5336 @subsection Examples
5338 Add temporal and uniform noise to input video:
5340 noise=alls=20:allf=t+u
5345 Pass the video source unchanged to the output.
5349 Apply video transform using libopencv.
5351 To enable this filter install libopencv library and headers and
5352 configure FFmpeg with @code{--enable-libopencv}.
5354 This filter accepts the following parameters:
5359 The name of the libopencv filter to apply.
5362 The parameters to pass to the libopencv filter. If not specified the default
5367 Refer to the official libopencv documentation for more precise
5369 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
5371 Follows the list of supported libopencv filters.
5376 Dilate an image by using a specific structuring element.
5377 This filter corresponds to the libopencv function @code{cvDilate}.
5379 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
5381 @var{struct_el} represents a structuring element, and has the syntax:
5382 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
5384 @var{cols} and @var{rows} represent the number of columns and rows of
5385 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
5386 point, and @var{shape} the shape for the structuring element, and
5387 can be one of the values "rect", "cross", "ellipse", "custom".
5389 If the value for @var{shape} is "custom", it must be followed by a
5390 string of the form "=@var{filename}". The file with name
5391 @var{filename} is assumed to represent a binary image, with each
5392 printable character corresponding to a bright pixel. When a custom
5393 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
5394 or columns and rows of the read file are assumed instead.
5396 The default value for @var{struct_el} is "3x3+0x0/rect".
5398 @var{nb_iterations} specifies the number of times the transform is
5399 applied to the image, and defaults to 1.
5401 Follow some example:
5403 # use the default values
5406 # dilate using a structuring element with a 5x5 cross, iterate two times
5407 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
5409 # read the shape from the file diamond.shape, iterate two times
5410 # the file diamond.shape may contain a pattern of characters like this:
5416 # the specified cols and rows are ignored (but not the anchor point coordinates)
5417 ocv=dilate:0x0+2x2/custom=diamond.shape|2
5422 Erode an image by using a specific structuring element.
5423 This filter corresponds to the libopencv function @code{cvErode}.
5425 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
5426 with the same syntax and semantics as the @ref{dilate} filter.
5430 Smooth the input video.
5432 The filter takes the following parameters:
5433 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
5435 @var{type} is the type of smooth filter to apply, and can be one of
5436 the following values: "blur", "blur_no_scale", "median", "gaussian",
5437 "bilateral". The default value is "gaussian".
5439 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
5440 parameters whose meanings depend on smooth type. @var{param1} and
5441 @var{param2} accept integer positive values or 0, @var{param3} and
5442 @var{param4} accept float values.
5444 The default value for @var{param1} is 3, the default value for the
5445 other parameters is 0.
5447 These parameters correspond to the parameters assigned to the
5448 libopencv function @code{cvSmooth}.
5453 Overlay one video on top of another.
5455 It takes two inputs and one output, the first input is the "main"
5456 video on which the second input is overlayed.
5458 This filter accepts the following parameters:
5460 A description of the accepted options follows.
5465 Set the expression for the x and y coordinates of the overlayed video
5466 on the main video. Default value is "0" for both expressions. In case
5467 the expression is invalid, it is set to a huge value (meaning that the
5468 overlay will not be displayed within the output visible area).
5471 Set when the expressions for @option{x}, and @option{y} are evaluated.
5473 It accepts the following values:
5476 only evaluate expressions once during the filter initialization or
5477 when a command is processed
5480 evaluate expressions for each incoming frame
5483 Default value is @samp{frame}.
5486 If set to 1, force the output to terminate when the shortest input
5487 terminates. Default value is 0.
5490 Set the format for the output video.
5492 It accepts the following values:
5504 Default value is @samp{yuv420}.
5506 @item rgb @emph{(deprecated)}
5507 If set to 1, force the filter to accept inputs in the RGB
5508 color space. Default value is 0. This option is deprecated, use
5509 @option{format} instead.
5512 If set to 1, force the filter to draw the last overlay frame over the
5513 main input until the end of the stream. A value of 0 disables this
5514 behavior. Default value is 1.
5517 The @option{x}, and @option{y} expressions can contain the following
5523 main input width and height
5527 overlay input width and height
5531 the computed values for @var{x} and @var{y}. They are evaluated for
5536 horizontal and vertical chroma subsample values of the output
5537 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
5541 the number of input frame, starting from 0
5544 the position in the file of the input frame, NAN if unknown
5547 timestamp expressed in seconds, NAN if the input timestamp is unknown
5550 Note that the @var{n}, @var{pos}, @var{t} variables are available only
5551 when evaluation is done @emph{per frame}, and will evaluate to NAN
5552 when @option{eval} is set to @samp{init}.
5554 Be aware that frames are taken from each input video in timestamp
5555 order, hence, if their initial timestamps differ, it is a good idea
5556 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
5557 have them begin in the same zero timestamp, as it does the example for
5558 the @var{movie} filter.
5560 You can chain together more overlays but you should test the
5561 efficiency of such approach.
5563 @subsection Commands
5565 This filter supports the following commands:
5569 Modify the x and y of the overlay input.
5570 The command accepts the same syntax of the corresponding option.
5572 If the specified expression is not valid, it is kept at its current
5576 @subsection Examples
5580 Draw the overlay at 10 pixels from the bottom right corner of the main
5583 overlay=main_w-overlay_w-10:main_h-overlay_h-10
5586 Using named options the example above becomes:
5588 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
5592 Insert a transparent PNG logo in the bottom left corner of the input,
5593 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
5595 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
5599 Insert 2 different transparent PNG logos (second logo on bottom
5600 right corner) using the @command{ffmpeg} tool:
5602 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
5606 Add a transparent color layer on top of the main video, @code{WxH}
5607 must specify the size of the main input to the overlay filter:
5609 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
5613 Play an original video and a filtered version (here with the deshake
5614 filter) side by side using the @command{ffplay} tool:
5616 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
5619 The above command is the same as:
5621 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
5625 Make a sliding overlay appearing from the left to the right top part of the
5626 screen starting since time 2:
5628 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
5632 Compose output by putting two input videos side to side:
5634 ffmpeg -i left.avi -i right.avi -filter_complex "
5635 nullsrc=size=200x100 [background];
5636 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
5637 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
5638 [background][left] overlay=shortest=1 [background+left];
5639 [background+left][right] overlay=shortest=1:x=100 [left+right]
5644 Chain several overlays in cascade:
5646 nullsrc=s=200x200 [bg];
5647 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
5648 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
5649 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
5650 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
5651 [in3] null, [mid2] overlay=100:100 [out0]
5658 Apply Overcomplete Wavelet denoiser.
5660 The filter accepts the following options:
5666 Larger depth values will denoise lower frequency components more, but
5667 slow down filtering.
5669 Must be an int in the range 8-16, default is @code{8}.
5671 @item luma_strength, ls
5674 Must be a double value in the range 0-1000, default is @code{1.0}.
5676 @item chroma_strength, cs
5677 Set chroma strength.
5679 Must be a double value in the range 0-1000, default is @code{1.0}.
5684 Add paddings to the input image, and place the original input at the
5685 given coordinates @var{x}, @var{y}.
5687 This filter accepts the following parameters:
5692 Specify an expression for the size of the output image with the
5693 paddings added. If the value for @var{width} or @var{height} is 0, the
5694 corresponding input size is used for the output.
5696 The @var{width} expression can reference the value set by the
5697 @var{height} expression, and vice versa.
5699 The default value of @var{width} and @var{height} is 0.
5703 Specify an expression for the offsets where to place the input image
5704 in the padded area with respect to the top/left border of the output
5707 The @var{x} expression can reference the value set by the @var{y}
5708 expression, and vice versa.
5710 The default value of @var{x} and @var{y} is 0.
5713 Specify the color of the padded area, it can be the name of a color
5714 (case insensitive match) or a 0xRRGGBB[AA] sequence.
5716 The default value of @var{color} is "black".
5719 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
5720 options are expressions containing the following constants:
5725 the input video width and height
5729 same as @var{in_w} and @var{in_h}
5733 the output width and height, that is the size of the padded area as
5734 specified by the @var{width} and @var{height} expressions
5738 same as @var{out_w} and @var{out_h}
5742 x and y offsets as specified by the @var{x} and @var{y}
5743 expressions, or NAN if not yet specified
5746 same as @var{iw} / @var{ih}
5749 input sample aspect ratio
5752 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
5756 horizontal and vertical chroma subsample values. For example for the
5757 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5760 @subsection Examples
5764 Add paddings with color "violet" to the input video. Output video
5765 size is 640x480, the top-left corner of the input video is placed at
5768 pad=640:480:0:40:violet
5771 The example above is equivalent to the following command:
5773 pad=width=640:height=480:x=0:y=40:color=violet
5777 Pad the input to get an output with dimensions increased by 3/2,
5778 and put the input video at the center of the padded area:
5780 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
5784 Pad the input to get a squared output with size equal to the maximum
5785 value between the input width and height, and put the input video at
5786 the center of the padded area:
5788 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
5792 Pad the input to get a final w/h ratio of 16:9:
5794 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
5798 In case of anamorphic video, in order to set the output display aspect
5799 correctly, it is necessary to use @var{sar} in the expression,
5800 according to the relation:
5802 (ih * X / ih) * sar = output_dar
5803 X = output_dar / sar
5806 Thus the previous example needs to be modified to:
5808 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
5812 Double output size and put the input video in the bottom-right
5813 corner of the output padded area:
5815 pad="2*iw:2*ih:ow-iw:oh-ih"
5819 @section perspective
5821 Correct perspective of video not recorded perpendicular to the screen.
5823 A description of the accepted parameters follows.
5834 Set coordinates expression for top left, top right, bottom left and bottom right corners.
5835 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
5837 The expressions can use the following variables:
5842 the width and height of video frame.
5846 Set interpolation for perspective correction.
5848 It accepts the following values:
5854 Default value is @samp{linear}.
5857 @section pixdesctest
5859 Pixel format descriptor test filter, mainly useful for internal
5860 testing. The output video should be equal to the input video.
5864 format=monow, pixdesctest
5867 can be used to test the monowhite pixel format descriptor definition.
5871 Enable the specified chain of postprocessing subfilters using libpostproc. This
5872 library should be automatically selected with a GPL build (@code{--enable-gpl}).
5873 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
5874 Each subfilter and some options have a short and a long name that can be used
5875 interchangeably, i.e. dr/dering are the same.
5877 The filters accept the following options:
5881 Set postprocessing subfilters string.
5884 All subfilters share common options to determine their scope:
5888 Honor the quality commands for this subfilter.
5891 Do chrominance filtering, too (default).
5894 Do luminance filtering only (no chrominance).
5897 Do chrominance filtering only (no luminance).
5900 These options can be appended after the subfilter name, separated by a '|'.
5902 Available subfilters are:
5905 @item hb/hdeblock[|difference[|flatness]]
5906 Horizontal deblocking filter
5909 Difference factor where higher values mean more deblocking (default: @code{32}).
5911 Flatness threshold where lower values mean more deblocking (default: @code{39}).
5914 @item vb/vdeblock[|difference[|flatness]]
5915 Vertical deblocking filter
5918 Difference factor where higher values mean more deblocking (default: @code{32}).
5920 Flatness threshold where lower values mean more deblocking (default: @code{39}).
5923 @item ha/hadeblock[|difference[|flatness]]
5924 Accurate horizontal deblocking filter
5927 Difference factor where higher values mean more deblocking (default: @code{32}).
5929 Flatness threshold where lower values mean more deblocking (default: @code{39}).
5932 @item va/vadeblock[|difference[|flatness]]
5933 Accurate vertical deblocking filter
5936 Difference factor where higher values mean more deblocking (default: @code{32}).
5938 Flatness threshold where lower values mean more deblocking (default: @code{39}).
5942 The horizontal and vertical deblocking filters share the difference and
5943 flatness values so you cannot set different horizontal and vertical
5948 Experimental horizontal deblocking filter
5951 Experimental vertical deblocking filter
5956 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
5959 larger -> stronger filtering
5961 larger -> stronger filtering
5963 larger -> stronger filtering
5966 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
5969 Stretch luminance to @code{0-255}.
5972 @item lb/linblenddeint
5973 Linear blend deinterlacing filter that deinterlaces the given block by
5974 filtering all lines with a @code{(1 2 1)} filter.
5976 @item li/linipoldeint
5977 Linear interpolating deinterlacing filter that deinterlaces the given block by
5978 linearly interpolating every second line.
5980 @item ci/cubicipoldeint
5981 Cubic interpolating deinterlacing filter deinterlaces the given block by
5982 cubically interpolating every second line.
5984 @item md/mediandeint
5985 Median deinterlacing filter that deinterlaces the given block by applying a
5986 median filter to every second line.
5988 @item fd/ffmpegdeint
5989 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
5990 second line with a @code{(-1 4 2 4 -1)} filter.
5993 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
5994 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
5996 @item fq/forceQuant[|quantizer]
5997 Overrides the quantizer table from the input with the constant quantizer you
6005 Default pp filter combination (@code{hb|a,vb|a,dr|a})
6008 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
6011 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
6014 @subsection Examples
6018 Apply horizontal and vertical deblocking, deringing and automatic
6019 brightness/contrast:
6025 Apply default filters without brightness/contrast correction:
6031 Apply default filters and temporal denoiser:
6033 pp=default/tmpnoise|1|2|3
6037 Apply deblocking on luminance only, and switch vertical deblocking on or off
6038 automatically depending on available CPU time:
6046 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
6047 Ratio) between two input videos.
6049 This filter takes in input two input videos, the first input is
6050 considered the "main" source and is passed unchanged to the
6051 output. The second input is used as a "reference" video for computing
6054 Both video inputs must have the same resolution and pixel format for
6055 this filter to work correctly. Also it assumes that both inputs
6056 have the same number of frames, which are compared one by one.
6058 The obtained average PSNR is printed through the logging system.
6060 The filter stores the accumulated MSE (mean squared error) of each
6061 frame, and at the end of the processing it is averaged across all frames
6062 equally, and the following formula is applied to obtain the PSNR:
6065 PSNR = 10*log10(MAX^2/MSE)
6068 Where MAX is the average of the maximum values of each component of the
6071 The description of the accepted parameters follows.
6075 If specified the filter will use the named file to save the PSNR of
6076 each individual frame.
6079 The file printed if @var{stats_file} is selected, contains a sequence of
6080 key/value pairs of the form @var{key}:@var{value} for each compared
6083 A description of each shown parameter follows:
6087 sequential number of the input frame, starting from 1
6090 Mean Square Error pixel-by-pixel average difference of the compared
6091 frames, averaged over all the image components.
6093 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
6094 Mean Square Error pixel-by-pixel average difference of the compared
6095 frames for the component specified by the suffix.
6097 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
6098 Peak Signal to Noise ratio of the compared frames for the component
6099 specified by the suffix.
6104 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
6105 [main][ref] psnr="stats_file=stats.log" [out]
6108 On this example the input file being processed is compared with the
6109 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
6110 is stored in @file{stats.log}.
6114 Suppress a TV station logo, using an image file to determine which
6115 pixels comprise the logo. It works by filling in the pixels that
6116 comprise the logo with neighboring pixels.
6118 The filter accepts the following options:
6122 Set the filter bitmap file, which can be any image format supported by
6123 libavformat. The width and height of the image file must match those of the
6124 video stream being processed.
6127 Pixels in the provided bitmap image with a value of zero are not
6128 considered part of the logo, non-zero pixels are considered part of
6129 the logo. If you use white (255) for the logo and black (0) for the
6130 rest, you will be safe. For making the filter bitmap, it is
6131 recommended to take a screen capture of a black frame with the logo
6132 visible, and then using a threshold filter followed by the erode
6133 filter once or twice.
6135 If needed, little splotches can be fixed manually. Remember that if
6136 logo pixels are not covered, the filter quality will be much
6137 reduced. Marking too many pixels as part of the logo does not hurt as
6138 much, but it will increase the amount of blurring needed to cover over
6139 the image and will destroy more information than necessary, and extra
6140 pixels will slow things down on a large logo.
6144 Rotate video by an arbitrary angle expressed in radians.
6146 The filter accepts the following options:
6148 A description of the optional parameters follows.
6151 Set an expression for the angle by which to rotate the input video
6152 clockwise, expressed as a number of radians. A negative value will
6153 result in a counter-clockwise rotation. By default it is set to "0".
6155 This expression is evaluated for each frame.
6158 Set the output width expression, default value is "iw".
6159 This expression is evaluated just once during configuration.
6162 Set the output height expression, default value is "ih".
6163 This expression is evaluated just once during configuration.
6166 Enable bilinear interpolation if set to 1, a value of 0 disables
6167 it. Default value is 1.
6170 Set the color used to fill the output area not covered by the rotated
6171 image. If the special value "none" is selected then no background is
6172 printed (useful for example if the background is never shown). Default
6176 The expressions for the angle and the output size can contain the
6177 following constants and functions:
6181 sequential number of the input frame, starting from 0. It is always NAN
6182 before the first frame is filtered.
6185 time in seconds of the input frame, it is set to 0 when the filter is
6186 configured. It is always NAN before the first frame is filtered.
6190 horizontal and vertical chroma subsample values. For example for the
6191 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6195 the input video width and heigth
6199 the output width and heigth, that is the size of the padded area as
6200 specified by the @var{width} and @var{height} expressions
6204 the minimal width/height required for completely containing the input
6205 video rotated by @var{a} radians.
6207 These are only available when computing the @option{out_w} and
6208 @option{out_h} expressions.
6211 @subsection Examples
6215 Rotate the input by PI/6 radians clockwise:
6221 Rotate the input by PI/6 radians counter-clockwise:
6227 Apply a constant rotation with period T, starting from an angle of PI/3:
6229 rotate=PI/3+2*PI*t/T
6233 Make the input video rotation oscillating with a period of T
6234 seconds and an amplitude of A radians:
6236 rotate=A*sin(2*PI/T*t)
6240 Rotate the video, output size is choosen so that the whole rotating
6241 input video is always completely contained in the output:
6243 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
6247 Rotate the video, reduce the output size so that no background is ever
6250 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
6254 @subsection Commands
6256 The filter supports the following commands:
6260 Set the angle expression.
6261 The command accepts the same syntax of the corresponding option.
6263 If the specified expression is not valid, it is kept at its current
6269 Apply Shape Adaptive Blur.
6271 The filter accepts the following options:
6274 @item luma_radius, lr
6275 Set luma blur filter strength, must be a value in range 0.1-4.0, default
6276 value is 1.0. A greater value will result in a more blurred image, and
6277 in slower processing.
6279 @item luma_pre_filter_radius, lpfr
6280 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
6283 @item luma_strength, ls
6284 Set luma maximum difference between pixels to still be considered, must
6285 be a value in the 0.1-100.0 range, default value is 1.0.
6287 @item chroma_radius, cr
6288 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
6289 greater value will result in a more blurred image, and in slower
6292 @item chroma_pre_filter_radius, cpfr
6293 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
6295 @item chroma_strength, cs
6296 Set chroma maximum difference between pixels to still be considered,
6297 must be a value in the 0.1-100.0 range.
6300 Each chroma option value, if not explicitly specified, is set to the
6301 corresponding luma option value.
6305 Scale (resize) the input video, using the libswscale library.
6307 The scale filter forces the output display aspect ratio to be the same
6308 of the input, by changing the output sample aspect ratio.
6310 If the input image format is different from the format requested by
6311 the next filter, the scale filter will convert the input to the
6315 The filter accepts the following options:
6320 Set the output video dimension expression. Default value is the input
6323 If the value is 0, the input width is used for the output.
6325 If one of the values is -1, the scale filter will use a value that
6326 maintains the aspect ratio of the input image, calculated from the
6327 other specified dimension. If both of them are -1, the input size is
6330 See below for the list of accepted constants for use in the dimension
6334 Set the interlacing mode. It accepts the following values:
6338 Force interlaced aware scaling.
6341 Do not apply interlaced scaling.
6344 Select interlaced aware scaling depending on whether the source frames
6345 are flagged as interlaced or not.
6348 Default value is @samp{0}.
6351 Set libswscale scaling flags. If not explictly specified the filter
6352 applies a bilinear scaling algorithm.
6355 Set the video size, the value must be a valid abbreviation or in the
6356 form @var{width}x@var{height}.
6358 @item in_color_matrix
6359 @item out_color_matrix
6360 Set in/output YCbCr color space type.
6362 This allows the autodetected value to be overridden as well as allows forcing
6363 a specific value used for the output and encoder.
6365 If not specified, the color space type depends on the pixel format.
6371 Choose automatically.
6374 Format conforming to International Telecommunication Union (ITU)
6375 Recommendation BT.709.
6378 Set color space conforming to the United States Federal Communications
6379 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
6382 Set color space conforming to:
6386 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
6389 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
6392 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
6397 Set color space conforming to SMPTE ST 240:1999.
6402 Set in/output YCbCr sample range.
6404 This allows the autodetected value to be overridden as well as allows forcing
6405 a specific value used for the output and encoder. If not specified, the
6406 range depends on the pixel format. Possible values:
6410 Choose automatically.
6413 Set full range (0-255 in case of 8-bit luma).
6416 Set "MPEG" range (16-235 in case of 8-bit luma).
6420 Set the dithering algorithm
6424 Choose automatically.
6433 error diffusion dither
6436 @item force_original_aspect_ratio
6437 Enable decreasing or increasing output video width or height if necessary to
6438 keep the original aspect ratio. Possible values:
6442 Scale the video as specified and disable this feature.
6445 The output video dimensions will automatically be decreased if needed.
6448 The output video dimensions will automatically be increased if needed.
6452 One useful instance of this option is that when you know a specific device's
6453 maximum allowed resolution, you can use this to limit the output video to
6454 that, while retaining the aspect ratio. For example, device A allows
6455 1280x720 playback, and your video is 1920x800. Using this option (set it to
6456 decrease) and specifying 1280x720 to the command line makes the output
6459 Please note that this is a different thing than specifying -1 for @option{w}
6460 or @option{h}, you still need to specify the output resolution for this option
6465 The values of the @option{w} and @option{h} options are expressions
6466 containing the following constants:
6471 the input width and height
6475 same as @var{in_w} and @var{in_h}
6479 the output (scaled) width and height
6483 same as @var{out_w} and @var{out_h}
6486 same as @var{iw} / @var{ih}
6489 input sample aspect ratio
6492 input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
6496 horizontal and vertical chroma subsample values. For example for the
6497 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6500 @subsection Examples
6504 Scale the input video to a size of 200x100:
6509 This is equivalent to:
6520 Specify a size abbreviation for the output size:
6525 which can also be written as:
6531 Scale the input to 2x:
6537 The above is the same as:
6543 Scale the input to 2x with forced interlaced scaling:
6545 scale=2*iw:2*ih:interl=1
6549 Scale the input to half size:
6555 Increase the width, and set the height to the same size:
6561 Seek for Greek harmony:
6568 Increase the height, and set the width to 3/2 of the height:
6570 scale=w=3/2*oh:h=3/5*ih
6574 Increase the size, but make the size a multiple of the chroma
6577 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
6581 Increase the width to a maximum of 500 pixels, keep the same input
6584 scale=w='min(500\, iw*3/2):h=-1'
6588 @section separatefields
6590 The @code{separatefields} takes a frame-based video input and splits
6591 each frame into its components fields, producing a new half height clip
6592 with twice the frame rate and twice the frame count.
6594 This filter use field-dominance information in frame to decide which
6595 of each pair of fields to place first in the output.
6596 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
6598 @section setdar, setsar
6600 The @code{setdar} filter sets the Display Aspect Ratio for the filter
6603 This is done by changing the specified Sample (aka Pixel) Aspect
6604 Ratio, according to the following equation:
6606 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
6609 Keep in mind that the @code{setdar} filter does not modify the pixel
6610 dimensions of the video frame. Also the display aspect ratio set by
6611 this filter may be changed by later filters in the filterchain,
6612 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
6615 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
6616 the filter output video.
6618 Note that as a consequence of the application of this filter, the
6619 output display aspect ratio will change according to the equation
6622 Keep in mind that the sample aspect ratio set by the @code{setsar}
6623 filter may be changed by later filters in the filterchain, e.g. if
6624 another "setsar" or a "setdar" filter is applied.
6626 The filters accept the following options:
6629 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
6630 Set the aspect ratio used by the filter.
6632 The parameter can be a floating point number string, an expression, or
6633 a string of the form @var{num}:@var{den}, where @var{num} and
6634 @var{den} are the numerator and denominator of the aspect ratio. If
6635 the parameter is not specified, it is assumed the value "0".
6636 In case the form "@var{num}:@var{den}" is used, the @code{:} character
6640 Set the maximum integer value to use for expressing numerator and
6641 denominator when reducing the expressed aspect ratio to a rational.
6642 Default value is @code{100}.
6646 @subsection Examples
6651 To change the display aspect ratio to 16:9, specify one of the following:
6659 To change the sample aspect ratio to 10:11, specify:
6665 To set a display aspect ratio of 16:9, and specify a maximum integer value of
6666 1000 in the aspect ratio reduction, use the command:
6668 setdar=ratio=16/9:max=1000
6676 Force field for the output video frame.
6678 The @code{setfield} filter marks the interlace type field for the
6679 output frames. It does not change the input frame, but only sets the
6680 corresponding property, which affects how the frame is treated by
6681 following filters (e.g. @code{fieldorder} or @code{yadif}).
6683 The filter accepts the following options:
6688 Available values are:
6692 Keep the same field property.
6695 Mark the frame as bottom-field-first.
6698 Mark the frame as top-field-first.
6701 Mark the frame as progressive.
6707 Show a line containing various information for each input video frame.
6708 The input video is not modified.
6710 The shown line contains a sequence of key/value pairs of the form
6711 @var{key}:@var{value}.
6713 A description of each shown parameter follows:
6717 sequential number of the input frame, starting from 0
6720 Presentation TimeStamp of the input frame, expressed as a number of
6721 time base units. The time base unit depends on the filter input pad.
6724 Presentation TimeStamp of the input frame, expressed as a number of
6728 position of the frame in the input stream, -1 if this information in
6729 unavailable and/or meaningless (for example in case of synthetic video)
6735 sample aspect ratio of the input frame, expressed in the form
6739 size of the input frame, expressed in the form
6740 @var{width}x@var{height}
6743 interlaced mode ("P" for "progressive", "T" for top field first, "B"
6744 for bottom field first)
6747 1 if the frame is a key frame, 0 otherwise
6750 picture type of the input frame ("I" for an I-frame, "P" for a
6751 P-frame, "B" for a B-frame, "?" for unknown type).
6752 Check also the documentation of the @code{AVPictureType} enum and of
6753 the @code{av_get_picture_type_char} function defined in
6754 @file{libavutil/avutil.h}.
6757 Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame
6759 @item plane_checksum
6760 Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
6761 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]"
6767 Blur the input video without impacting the outlines.
6769 The filter accepts the following options:
6772 @item luma_radius, lr
6773 Set the luma radius. The option value must be a float number in
6774 the range [0.1,5.0] that specifies the variance of the gaussian filter
6775 used to blur the image (slower if larger). Default value is 1.0.
6777 @item luma_strength, ls
6778 Set the luma strength. The option value must be a float number
6779 in the range [-1.0,1.0] that configures the blurring. A value included
6780 in [0.0,1.0] will blur the image whereas a value included in
6781 [-1.0,0.0] will sharpen the image. Default value is 1.0.
6783 @item luma_threshold, lt
6784 Set the luma threshold used as a coefficient to determine
6785 whether a pixel should be blurred or not. The option value must be an
6786 integer in the range [-30,30]. A value of 0 will filter all the image,
6787 a value included in [0,30] will filter flat areas and a value included
6788 in [-30,0] will filter edges. Default value is 0.
6790 @item chroma_radius, cr
6791 Set the chroma radius. The option value must be a float number in
6792 the range [0.1,5.0] that specifies the variance of the gaussian filter
6793 used to blur the image (slower if larger). Default value is 1.0.
6795 @item chroma_strength, cs
6796 Set the chroma strength. The option value must be a float number
6797 in the range [-1.0,1.0] that configures the blurring. A value included
6798 in [0.0,1.0] will blur the image whereas a value included in
6799 [-1.0,0.0] will sharpen the image. Default value is 1.0.
6801 @item chroma_threshold, ct
6802 Set the chroma threshold used as a coefficient to determine
6803 whether a pixel should be blurred or not. The option value must be an
6804 integer in the range [-30,30]. A value of 0 will filter all the image,
6805 a value included in [0,30] will filter flat areas and a value included
6806 in [-30,0] will filter edges. Default value is 0.
6809 If a chroma option is not explicitly set, the corresponding luma value
6814 Convert between different stereoscopic image formats.
6816 The filters accept the following options:
6820 Set stereoscopic image format of input.
6822 Available values for input image formats are:
6825 side by side parallel (left eye left, right eye right)
6828 side by side crosseye (right eye left, left eye right)
6831 side by side parallel with half width resolution
6832 (left eye left, right eye right)
6835 side by side crosseye with half width resolution
6836 (right eye left, left eye right)
6839 above-below (left eye above, right eye below)
6842 above-below (right eye above, left eye below)
6845 above-below with half height resolution
6846 (left eye above, right eye below)
6849 above-below with half height resolution
6850 (right eye above, left eye below)
6853 alternating frames (left eye first, right eye second)
6856 alternating frames (right eye first, left eye second)
6858 Default value is @samp{sbsl}.
6862 Set stereoscopic image format of output.
6864 Available values for output image formats are all the input formats as well as:
6867 anaglyph red/blue gray
6868 (red filter on left eye, blue filter on right eye)
6871 anaglyph red/green gray
6872 (red filter on left eye, green filter on right eye)
6875 anaglyph red/cyan gray
6876 (red filter on left eye, cyan filter on right eye)
6879 anaglyph red/cyan half colored
6880 (red filter on left eye, cyan filter on right eye)
6883 anaglyph red/cyan color
6884 (red filter on left eye, cyan filter on right eye)
6887 anaglyph red/cyan color optimized with the least squares projection of dubois
6888 (red filter on left eye, cyan filter on right eye)
6891 anaglyph green/magenta gray
6892 (green filter on left eye, magenta filter on right eye)
6895 anaglyph green/magenta half colored
6896 (green filter on left eye, magenta filter on right eye)
6899 anaglyph green/magenta colored
6900 (green filter on left eye, magenta filter on right eye)
6903 anaglyph green/magenta color optimized with the least squares projection of dubois
6904 (green filter on left eye, magenta filter on right eye)
6907 anaglyph yellow/blue gray
6908 (yellow filter on left eye, blue filter on right eye)
6911 anaglyph yellow/blue half colored
6912 (yellow filter on left eye, blue filter on right eye)
6915 anaglyph yellow/blue colored
6916 (yellow filter on left eye, blue filter on right eye)
6919 anaglyph yellow/blue color optimized with the least squares projection of dubois
6920 (yellow filter on left eye, blue filter on right eye)
6923 interleaved rows (left eye has top row, right eye starts on next row)
6926 interleaved rows (right eye has top row, left eye starts on next row)
6929 mono output (left eye only)
6932 mono output (right eye only)
6935 Default value is @samp{arcd}.
6938 @subsection Examples
6942 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
6948 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
6956 Apply a simple postprocessing filter that compresses and decompresses the image
6957 at several (or - in the case of @option{quality} level @code{6} - all) shifts
6958 and average the results.
6960 The filter accepts the following options:
6964 Set quality. This option defines the number of levels for averaging. It accepts
6965 an integer in the range 0-6. If set to @code{0}, the filter will have no
6966 effect. A value of @code{6} means the higher quality. For each increment of
6967 that value the speed drops by a factor of approximately 2. Default value is
6971 Force a constant quantization parameter. If not set, the filter will use the QP
6972 from the video stream (if available).
6975 Set thresholding mode. Available modes are:
6979 Set hard thresholding (default).
6981 Set soft thresholding (better de-ringing effect, but likely blurrier).
6985 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
6986 option may cause flicker since the B-Frames have often larger QP. Default is
6987 @code{0} (not enabled).
6993 Draw subtitles on top of input video using the libass library.
6995 To enable compilation of this filter you need to configure FFmpeg with
6996 @code{--enable-libass}. This filter also requires a build with libavcodec and
6997 libavformat to convert the passed subtitles file to ASS (Advanced Substation
6998 Alpha) subtitles format.
7000 The filter accepts the following options:
7004 Set the filename of the subtitle file to read. It must be specified.
7007 Specify the size of the original video, the video for which the ASS file
7008 was composed. Due to a misdesign in ASS aspect ratio arithmetic, this is
7009 necessary to correctly scale the fonts if the aspect ratio has been changed.
7012 Set subtitles input character encoding. @code{subtitles} filter only. Only
7013 useful if not UTF-8.
7016 If the first key is not specified, it is assumed that the first value
7017 specifies the @option{filename}.
7019 For example, to render the file @file{sub.srt} on top of the input
7020 video, use the command:
7025 which is equivalent to:
7027 subtitles=filename=sub.srt
7032 Scale the input by 2x and smooth using the Super2xSaI (Scale and
7033 Interpolate) pixel art scaling algorithm.
7035 Useful for enlarging pixel art images without reducing sharpness.
7042 Apply telecine process to the video.
7044 This filter accepts the following options:
7053 The default value is @code{top}.
7057 A string of numbers representing the pulldown pattern you wish to apply.
7058 The default value is @code{23}.
7062 Some typical patterns:
7067 24p: 2332 (preferred)
7074 24p: 222222222223 ("Euro pulldown")
7080 Select the most representative frame in a given sequence of consecutive frames.
7082 The filter accepts the following options:
7086 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
7087 will pick one of them, and then handle the next batch of @var{n} frames until
7088 the end. Default is @code{100}.
7091 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
7092 value will result in a higher memory usage, so a high value is not recommended.
7094 @subsection Examples
7098 Extract one picture each 50 frames:
7104 Complete example of a thumbnail creation with @command{ffmpeg}:
7106 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
7112 Tile several successive frames together.
7114 The filter accepts the following options:
7119 Set the grid size (i.e. the number of lines and columns) in the form
7123 Set the maximum number of frames to render in the given area. It must be less
7124 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
7125 the area will be used.
7128 Set the outer border margin in pixels.
7131 Set the inner border thickness (i.e. the number of pixels between frames). For
7132 more advanced padding options (such as having different values for the edges),
7133 refer to the pad video filter.
7136 Specify the color of the unused area, it can be the name of a color
7137 (case insensitive match) or a 0xRRGGBB[AA] sequence.
7138 The default value of @var{color} is "black".
7141 @subsection Examples
7145 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
7147 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
7149 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
7150 duplicating each output frame to accomodate the originally detected frame
7154 Display @code{5} pictures in an area of @code{3x2} frames,
7155 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
7156 mixed flat and named options:
7158 tile=3x2:nb_frames=5:padding=7:margin=2
7164 Perform various types of temporal field interlacing.
7166 Frames are counted starting from 1, so the first input frame is
7169 The filter accepts the following options:
7174 Specify the mode of the interlacing. This option can also be specified
7175 as a value alone. See below for a list of values for this option.
7177 Available values are:
7181 Move odd frames into the upper field, even into the lower field,
7182 generating a double height frame at half frame rate.
7185 Only output even frames, odd frames are dropped, generating a frame with
7186 unchanged height at half frame rate.
7189 Only output odd frames, even frames are dropped, generating a frame with
7190 unchanged height at half frame rate.
7193 Expand each frame to full height, but pad alternate lines with black,
7194 generating a frame with double height at the same input frame rate.
7196 @item interleave_top, 4
7197 Interleave the upper field from odd frames with the lower field from
7198 even frames, generating a frame with unchanged height at half frame rate.
7200 @item interleave_bottom, 5
7201 Interleave the lower field from odd frames with the upper field from
7202 even frames, generating a frame with unchanged height at half frame rate.
7204 @item interlacex2, 6
7205 Double frame rate with unchanged height. Frames are inserted each
7206 containing the second temporal field from the previous input frame and
7207 the first temporal field from the next input frame. This mode relies on
7208 the top_field_first flag. Useful for interlaced video displays with no
7209 field synchronisation.
7212 Numeric values are deprecated but are accepted for backward
7213 compatibility reasons.
7215 Default mode is @code{merge}.
7218 Specify flags influencing the filter process.
7220 Available value for @var{flags} is:
7223 @item low_pass_filter, vlfp
7224 Enable vertical low-pass filtering in the filter.
7225 Vertical low-pass filtering is required when creating an interlaced
7226 destination from a progressive source which contains high-frequency
7227 vertical detail. Filtering will reduce interlace 'twitter' and Moire
7230 Vertical low-pass filtering can only be enabled for @option{mode}
7231 @var{interleave_top} and @var{interleave_bottom}.
7238 Transpose rows with columns in the input video and optionally flip it.
7240 This filter accepts the following options:
7245 Specify the transposition direction.
7247 Can assume the following values:
7249 @item 0, 4, cclock_flip
7250 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
7258 Rotate by 90 degrees clockwise, that is:
7266 Rotate by 90 degrees counterclockwise, that is:
7273 @item 3, 7, clock_flip
7274 Rotate by 90 degrees clockwise and vertically flip, that is:
7282 For values between 4-7, the transposition is only done if the input
7283 video geometry is portrait and not landscape. These values are
7284 deprecated, the @code{passthrough} option should be used instead.
7286 Numerical values are deprecated, and should be dropped in favor of
7290 Do not apply the transposition if the input geometry matches the one
7291 specified by the specified value. It accepts the following values:
7294 Always apply transposition.
7296 Preserve portrait geometry (when @var{height} >= @var{width}).
7298 Preserve landscape geometry (when @var{width} >= @var{height}).
7301 Default value is @code{none}.
7304 For example to rotate by 90 degrees clockwise and preserve portrait
7307 transpose=dir=1:passthrough=portrait
7310 The command above can also be specified as:
7312 transpose=1:portrait
7316 Trim the input so that the output contains one continuous subpart of the input.
7318 This filter accepts the following options:
7321 Specify time of the start of the kept section, i.e. the frame with the
7322 timestamp @var{start} will be the first frame in the output.
7325 Specify time of the first frame that will be dropped, i.e. the frame
7326 immediately preceding the one with the timestamp @var{end} will be the last
7327 frame in the output.
7330 Same as @var{start}, except this option sets the start timestamp in timebase
7331 units instead of seconds.
7334 Same as @var{end}, except this option sets the end timestamp in timebase units
7338 Specify maximum duration of the output.
7341 Number of the first frame that should be passed to output.
7344 Number of the first frame that should be dropped.
7347 @option{start}, @option{end}, @option{duration} are expressed as time
7348 duration specifications, check the "Time duration" section in the
7349 ffmpeg-utils manual.
7351 Note that the first two sets of the start/end options and the @option{duration}
7352 option look at the frame timestamp, while the _frame variants simply count the
7353 frames that pass through the filter. Also note that this filter does not modify
7354 the timestamps. If you wish that the output timestamps start at zero, insert a
7355 setpts filter after the trim filter.
7357 If multiple start or end options are set, this filter tries to be greedy and
7358 keep all the frames that match at least one of the specified constraints. To keep
7359 only the part that matches all the constraints at once, chain multiple trim
7362 The defaults are such that all the input is kept. So it is possible to set e.g.
7363 just the end values to keep everything before the specified time.
7368 drop everything except the second minute of input
7370 ffmpeg -i INPUT -vf trim=60:120
7374 keep only the first second
7376 ffmpeg -i INPUT -vf trim=duration=1
7384 Sharpen or blur the input video.
7386 It accepts the following parameters:
7389 @item luma_msize_x, lx
7390 Set the luma matrix horizontal size. It must be an odd integer between
7391 3 and 63, default value is 5.
7393 @item luma_msize_y, ly
7394 Set the luma matrix vertical size. It must be an odd integer between 3
7395 and 63, default value is 5.
7397 @item luma_amount, la
7398 Set the luma effect strength. It can be a float number, reasonable
7399 values lay between -1.5 and 1.5.
7401 Negative values will blur the input video, while positive values will
7402 sharpen it, a value of zero will disable the effect.
7404 Default value is 1.0.
7406 @item chroma_msize_x, cx
7407 Set the chroma matrix horizontal size. It must be an odd integer
7408 between 3 and 63, default value is 5.
7410 @item chroma_msize_y, cy
7411 Set the chroma matrix vertical size. It must be an odd integer
7412 between 3 and 63, default value is 5.
7414 @item chroma_amount, ca
7415 Set the chroma effect strength. It can be a float number, reasonable
7416 values lay between -1.5 and 1.5.
7418 Negative values will blur the input video, while positive values will
7419 sharpen it, a value of zero will disable the effect.
7421 Default value is 0.0.
7424 If set to 1, specify using OpenCL capabilities, only available if
7425 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
7429 All parameters are optional and default to the equivalent of the
7430 string '5:5:1.0:5:5:0.0'.
7432 @subsection Examples
7436 Apply strong luma sharpen effect:
7438 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
7442 Apply strong blur of both luma and chroma parameters:
7444 unsharp=7:7:-2:7:7:-2
7448 @anchor{vidstabdetect}
7449 @section vidstabdetect
7451 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
7452 @ref{vidstabtransform} for pass 2.
7454 This filter generates a file with relative translation and rotation
7455 transform information about subsequent frames, which is then used by
7456 the @ref{vidstabtransform} filter.
7458 To enable compilation of this filter you need to configure FFmpeg with
7459 @code{--enable-libvidstab}.
7461 This filter accepts the following options:
7465 Set the path to the file used to write the transforms information.
7466 Default value is @file{transforms.trf}.
7469 Set how shaky the video is and how quick the camera is. It accepts an
7470 integer in the range 1-10, a value of 1 means little shakiness, a
7471 value of 10 means strong shakiness. Default value is 5.
7474 Set the accuracy of the detection process. It must be a value in the
7475 range 1-15. A value of 1 means low accuracy, a value of 15 means high
7476 accuracy. Default value is 9.
7479 Set stepsize of the search process. The region around minimum is
7480 scanned with 1 pixel resolution. Default value is 6.
7483 Set minimum contrast. Below this value a local measurement field is
7484 discarded. Must be a floating point value in the range 0-1. Default
7488 Set reference frame number for tripod mode.
7490 If enabled, the motion of the frames is compared to a reference frame
7491 in the filtered stream, identified by the specified number. The idea
7492 is to compensate all movements in a more-or-less static scene and keep
7493 the camera view absolutely still.
7495 If set to 0, it is disabled. The frames are counted starting from 1.
7498 Show fields and transforms in the resulting frames. It accepts an
7499 integer in the range 0-2. Default value is 0, which disables any
7503 @subsection Examples
7513 Analyze strongly shaky movie and put the results in file
7514 @file{mytransforms.trf}:
7516 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
7520 Visualize the result of internal transformations in the resulting
7523 vidstabdetect=show=1
7527 Analyze a video with medium shakiness using @command{ffmpeg}:
7529 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
7533 @anchor{vidstabtransform}
7534 @section vidstabtransform
7536 Video stabilization/deshaking: pass 2 of 2,
7537 see @ref{vidstabdetect} for pass 1.
7539 Read a file with transform information for each frame and
7540 apply/compensate them. Together with the @ref{vidstabdetect}
7541 filter this can be used to deshake videos. See also
7542 @url{http://public.hronopik.de/vid.stab}. It is important to also use
7543 the unsharp filter, see below.
7545 To enable compilation of this filter you need to configure FFmpeg with
7546 @code{--enable-libvidstab}.
7548 This filter accepts the following options:
7553 path to the file used to read the transforms (default: @file{transforms.trf})
7556 number of frames (value*2 + 1) used for lowpass filtering the camera movements
7557 (default: 10). For example a number of 10 means that 21 frames are used
7558 (10 in the past and 10 in the future) to smoothen the motion in the
7559 video. A larger values leads to a smoother video, but limits the
7560 acceleration of the camera (pan/tilt movements).
7563 maximal number of pixels to translate frames (default: -1 no limit)
7566 maximal angle in radians (degree*PI/180) to rotate frames (default: -1
7570 How to deal with borders that may be visible due to movement
7571 compensation. Available values are:
7575 keep image information from previous frame (default)
7577 fill the border black
7583 keep transforms normal (default)
7590 consider transforms as
7595 relative to previous frame (default)
7600 percentage to zoom (default: 0)
7609 if 1 then optimal zoom value is determined (default).
7610 Optimal zoom means no (or only little) border should be visible.
7611 Note that the value given at zoom is added to the one calculated
7615 type of interpolation
7617 Available values are:
7622 linear only horizontal
7624 linear in both directions (default)
7626 cubic in both directions (slow)
7630 virtual tripod mode means that the video is stabilized such that the
7631 camera stays stationary. Use also @code{tripod} option of
7632 @ref{vidstabdetect}.
7637 virtual tripod mode: equivalent to @code{relative=0:smoothing=0}
7642 @subsection Examples
7646 typical call with default default values:
7647 (note the unsharp filter which is always recommended)
7649 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
7653 zoom in a bit more and load transform data from a given file
7655 vidstabtransform=zoom=5:input="mytransforms.trf"
7659 smoothen the video even more
7661 vidstabtransform=smoothing=30
7668 Flip the input video vertically.
7670 For example, to vertically flip a video with @command{ffmpeg}:
7672 ffmpeg -i in.avi -vf "vflip" out.avi
7677 Make or reverse a natural vignetting effect.
7679 The filter accepts the following options:
7683 Set lens angle expression as a number of radians.
7685 The value is clipped in the @code{[0,PI/2]} range.
7687 Default value: @code{"PI/5"}
7691 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
7695 Set forward/backward mode.
7697 Available modes are:
7700 The larger the distance from the central point, the darker the image becomes.
7703 The larger the distance from the central point, the brighter the image becomes.
7704 This can be used to reverse a vignette effect, though there is no automatic
7705 detection to extract the lens @option{angle} and other settings (yet). It can
7706 also be used to create a burning effect.
7709 Default value is @samp{forward}.
7712 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
7714 It accepts the following values:
7717 Evaluate expressions only once during the filter initialization.
7720 Evaluate expressions for each incoming frame. This is way slower than the
7721 @samp{init} mode since it requires all the scalers to be re-computed, but it
7722 allows advanced dynamic expressions.
7725 Default value is @samp{init}.
7728 Set dithering to reduce the circular banding effects. Default is @code{1}
7732 Set vignette aspect. This setting allows to adjust the shape of the vignette.
7733 Setting this value to the SAR of the input will make a rectangular vignetting
7734 following the dimensions of the video.
7736 Default is @code{1/1}.
7739 @subsection Expressions
7741 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
7742 following parameters.
7747 input width and height
7750 the number of input frame, starting from 0
7753 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
7754 @var{TB} units, NAN if undefined
7757 frame rate of the input video, NAN if the input frame rate is unknown
7760 the PTS (Presentation TimeStamp) of the filtered video frame,
7761 expressed in seconds, NAN if undefined
7764 time base of the input video
7768 @subsection Examples
7772 Apply simple strong vignetting effect:
7778 Make a flickering vignetting:
7780 vignette='PI/4+random(1)*PI/50':eval=frame
7788 Deinterlace the input video ("yadif" means "yet another deinterlacing
7791 This filter accepts the following options:
7797 The interlacing mode to adopt, accepts one of the following values:
7801 output 1 frame for each frame
7803 output 1 frame for each field
7804 @item 2, send_frame_nospatial
7805 like @code{send_frame} but skip spatial interlacing check
7806 @item 3, send_field_nospatial
7807 like @code{send_field} but skip spatial interlacing check
7810 Default value is @code{send_frame}.
7813 The picture field parity assumed for the input interlaced video, accepts one of
7814 the following values:
7818 assume top field first
7820 assume bottom field first
7822 enable automatic detection
7825 Default value is @code{auto}.
7826 If interlacing is unknown or decoder does not export this information,
7827 top field first will be assumed.
7830 Specify which frames to deinterlace. Accept one of the following
7835 deinterlace all frames
7837 only deinterlace frames marked as interlaced
7840 Default value is @code{all}.
7843 @c man end VIDEO FILTERS
7845 @chapter Video Sources
7846 @c man begin VIDEO SOURCES
7848 Below is a description of the currently available video sources.
7852 Buffer video frames, and make them available to the filter chain.
7854 This source is mainly intended for a programmatic use, in particular
7855 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
7857 This source accepts the following options:
7862 Specify the size (width and height) of the buffered video frames.
7871 A string representing the pixel format of the buffered video frames.
7872 It may be a number corresponding to a pixel format, or a pixel format
7876 Specify the timebase assumed by the timestamps of the buffered frames.
7879 Specify the frame rate expected for the video stream.
7881 @item pixel_aspect, sar
7882 Specify the sample aspect ratio assumed by the video frames.
7885 Specify the optional parameters to be used for the scale filter which
7886 is automatically inserted when an input change is detected in the
7887 input size or format.
7892 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
7895 will instruct the source to accept video frames with size 320x240 and
7896 with format "yuv410p", assuming 1/24 as the timestamps timebase and
7897 square pixels (1:1 sample aspect ratio).
7898 Since the pixel format with name "yuv410p" corresponds to the number 6
7899 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
7900 this example corresponds to:
7902 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
7905 Alternatively, the options can be specified as a flat string, but this
7906 syntax is deprecated:
7908 @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}]
7912 Create a pattern generated by an elementary cellular automaton.
7914 The initial state of the cellular automaton can be defined through the
7915 @option{filename}, and @option{pattern} options. If such options are
7916 not specified an initial state is created randomly.
7918 At each new frame a new row in the video is filled with the result of
7919 the cellular automaton next generation. The behavior when the whole
7920 frame is filled is defined by the @option{scroll} option.
7922 This source accepts the following options:
7926 Read the initial cellular automaton state, i.e. the starting row, from
7928 In the file, each non-whitespace character is considered an alive
7929 cell, a newline will terminate the row, and further characters in the
7930 file will be ignored.
7933 Read the initial cellular automaton state, i.e. the starting row, from
7934 the specified string.
7936 Each non-whitespace character in the string is considered an alive
7937 cell, a newline will terminate the row, and further characters in the
7938 string will be ignored.
7941 Set the video rate, that is the number of frames generated per second.
7944 @item random_fill_ratio, ratio
7945 Set the random fill ratio for the initial cellular automaton row. It
7946 is a floating point number value ranging from 0 to 1, defaults to
7949 This option is ignored when a file or a pattern is specified.
7951 @item random_seed, seed
7952 Set the seed for filling randomly the initial row, must be an integer
7953 included between 0 and UINT32_MAX. If not specified, or if explicitly
7954 set to -1, the filter will try to use a good random seed on a best
7958 Set the cellular automaton rule, it is a number ranging from 0 to 255.
7959 Default value is 110.
7962 Set the size of the output video.
7964 If @option{filename} or @option{pattern} is specified, the size is set
7965 by default to the width of the specified initial state row, and the
7966 height is set to @var{width} * PHI.
7968 If @option{size} is set, it must contain the width of the specified
7969 pattern string, and the specified pattern will be centered in the
7972 If a filename or a pattern string is not specified, the size value
7973 defaults to "320x518" (used for a randomly generated initial state).
7976 If set to 1, scroll the output upward when all the rows in the output
7977 have been already filled. If set to 0, the new generated row will be
7978 written over the top row just after the bottom row is filled.
7981 @item start_full, full
7982 If set to 1, completely fill the output with generated rows before
7983 outputting the first frame.
7984 This is the default behavior, for disabling set the value to 0.
7987 If set to 1, stitch the left and right row edges together.
7988 This is the default behavior, for disabling set the value to 0.
7991 @subsection Examples
7995 Read the initial state from @file{pattern}, and specify an output of
7998 cellauto=f=pattern:s=200x400
8002 Generate a random initial row with a width of 200 cells, with a fill
8005 cellauto=ratio=2/3:s=200x200
8009 Create a pattern generated by rule 18 starting by a single alive cell
8010 centered on an initial row with width 100:
8012 cellauto=p=@@:s=100x400:full=0:rule=18
8016 Specify a more elaborated initial pattern:
8018 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
8025 Generate a Mandelbrot set fractal, and progressively zoom towards the
8026 point specified with @var{start_x} and @var{start_y}.
8028 This source accepts the following options:
8033 Set the terminal pts value. Default value is 400.
8036 Set the terminal scale value.
8037 Must be a floating point value. Default value is 0.3.
8040 Set the inner coloring mode, that is the algorithm used to draw the
8041 Mandelbrot fractal internal region.
8043 It shall assume one of the following values:
8048 Show time until convergence.
8050 Set color based on point closest to the origin of the iterations.
8055 Default value is @var{mincol}.
8058 Set the bailout value. Default value is 10.0.
8061 Set the maximum of iterations performed by the rendering
8062 algorithm. Default value is 7189.
8065 Set outer coloring mode.
8066 It shall assume one of following values:
8068 @item iteration_count
8069 Set iteration cound mode.
8070 @item normalized_iteration_count
8071 set normalized iteration count mode.
8073 Default value is @var{normalized_iteration_count}.
8076 Set frame rate, expressed as number of frames per second. Default
8080 Set frame size. Default value is "640x480".
8083 Set the initial scale value. Default value is 3.0.
8086 Set the initial x position. Must be a floating point value between
8087 -100 and 100. Default value is -0.743643887037158704752191506114774.
8090 Set the initial y position. Must be a floating point value between
8091 -100 and 100. Default value is -0.131825904205311970493132056385139.
8096 Generate various test patterns, as generated by the MPlayer test filter.
8098 The size of the generated video is fixed, and is 256x256.
8099 This source is useful in particular for testing encoding features.
8101 This source accepts the following options:
8106 Specify the frame rate of the sourced video, as the number of frames
8107 generated per second. It has to be a string in the format
8108 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
8109 number or a valid video frame rate abbreviation. The default value is
8113 Set the video duration of the sourced video. The accepted syntax is:
8118 See also the function @code{av_parse_time()}.
8120 If not specified, or the expressed duration is negative, the video is
8121 supposed to be generated forever.
8125 Set the number or the name of the test to perform. Supported tests are:
8140 Default value is "all", which will cycle through the list of all tests.
8143 For example the following:
8148 will generate a "dc_luma" test pattern.
8152 Provide a frei0r source.
8154 To enable compilation of this filter you need to install the frei0r
8155 header and configure FFmpeg with @code{--enable-frei0r}.
8157 This source accepts the following options:
8162 The size of the video to generate, may be a string of the form
8163 @var{width}x@var{height} or a frame size abbreviation.
8166 Framerate of the generated video, may be a string of the form
8167 @var{num}/@var{den} or a frame rate abbreviation.
8170 The name to the frei0r source to load. For more information regarding frei0r and
8171 how to set the parameters read the section @ref{frei0r} in the description of
8175 A '|'-separated list of parameters to pass to the frei0r source.
8179 For example, to generate a frei0r partik0l source with size 200x200
8180 and frame rate 10 which is overlayed on the overlay filter main input:
8182 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
8187 Generate a life pattern.
8189 This source is based on a generalization of John Conway's life game.
8191 The sourced input represents a life grid, each pixel represents a cell
8192 which can be in one of two possible states, alive or dead. Every cell
8193 interacts with its eight neighbours, which are the cells that are
8194 horizontally, vertically, or diagonally adjacent.
8196 At each interaction the grid evolves according to the adopted rule,
8197 which specifies the number of neighbor alive cells which will make a
8198 cell stay alive or born. The @option{rule} option allows to specify
8201 This source accepts the following options:
8205 Set the file from which to read the initial grid state. In the file,
8206 each non-whitespace character is considered an alive cell, and newline
8207 is used to delimit the end of each row.
8209 If this option is not specified, the initial grid is generated
8213 Set the video rate, that is the number of frames generated per second.
8216 @item random_fill_ratio, ratio
8217 Set the random fill ratio for the initial random grid. It is a
8218 floating point number value ranging from 0 to 1, defaults to 1/PHI.
8219 It is ignored when a file is specified.
8221 @item random_seed, seed
8222 Set the seed for filling the initial random grid, must be an integer
8223 included between 0 and UINT32_MAX. If not specified, or if explicitly
8224 set to -1, the filter will try to use a good random seed on a best
8230 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
8231 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
8232 @var{NS} specifies the number of alive neighbor cells which make a
8233 live cell stay alive, and @var{NB} the number of alive neighbor cells
8234 which make a dead cell to become alive (i.e. to "born").
8235 "s" and "b" can be used in place of "S" and "B", respectively.
8237 Alternatively a rule can be specified by an 18-bits integer. The 9
8238 high order bits are used to encode the next cell state if it is alive
8239 for each number of neighbor alive cells, the low order bits specify
8240 the rule for "borning" new cells. Higher order bits encode for an
8241 higher number of neighbor cells.
8242 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
8243 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
8245 Default value is "S23/B3", which is the original Conway's game of life
8246 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
8247 cells, and will born a new cell if there are three alive cells around
8251 Set the size of the output video.
8253 If @option{filename} is specified, the size is set by default to the
8254 same size of the input file. If @option{size} is set, it must contain
8255 the size specified in the input file, and the initial grid defined in
8256 that file is centered in the larger resulting area.
8258 If a filename is not specified, the size value defaults to "320x240"
8259 (used for a randomly generated initial grid).
8262 If set to 1, stitch the left and right grid edges together, and the
8263 top and bottom edges also. Defaults to 1.
8266 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
8267 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
8268 value from 0 to 255.
8271 Set the color of living (or new born) cells.
8274 Set the color of dead cells. If @option{mold} is set, this is the first color
8275 used to represent a dead cell.
8278 Set mold color, for definitely dead and moldy cells.
8281 @subsection Examples
8285 Read a grid from @file{pattern}, and center it on a grid of size
8288 life=f=pattern:s=300x300
8292 Generate a random grid of size 200x200, with a fill ratio of 2/3:
8294 life=ratio=2/3:s=200x200
8298 Specify a custom rule for evolving a randomly generated grid:
8304 Full example with slow death effect (mold) using @command{ffplay}:
8306 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
8311 @anchor{haldclutsrc}
8315 @anchor{smptehdbars}
8317 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
8319 The @code{color} source provides an uniformly colored input.
8321 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
8322 @ref{haldclut} filter.
8324 The @code{nullsrc} source returns unprocessed video frames. It is
8325 mainly useful to be employed in analysis / debugging tools, or as the
8326 source for filters which ignore the input data.
8328 The @code{rgbtestsrc} source generates an RGB test pattern useful for
8329 detecting RGB vs BGR issues. You should see a red, green and blue
8330 stripe from top to bottom.
8332 The @code{smptebars} source generates a color bars pattern, based on
8333 the SMPTE Engineering Guideline EG 1-1990.
8335 The @code{smptehdbars} source generates a color bars pattern, based on
8336 the SMPTE RP 219-2002.
8338 The @code{testsrc} source generates a test video pattern, showing a
8339 color pattern, a scrolling gradient and a timestamp. This is mainly
8340 intended for testing purposes.
8342 The sources accept the following options:
8347 Specify the color of the source, only available in the @code{color}
8348 source. It can be the name of a color (case insensitive match) or a
8349 0xRRGGBB[AA] sequence, possibly followed by an alpha specifier. The
8350 default value is "black".
8353 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
8354 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
8355 pixels to be used as identity matrix for 3D lookup tables. Each component is
8356 coded on a @code{1/(N*N)} scale.
8359 Specify the size of the sourced video, it may be a string of the form
8360 @var{width}x@var{height}, or the name of a size abbreviation. The
8361 default value is "320x240".
8363 This option is not available with the @code{haldclutsrc} filter.
8366 Specify the frame rate of the sourced video, as the number of frames
8367 generated per second. It has to be a string in the format
8368 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
8369 number or a valid video frame rate abbreviation. The default value is
8373 Set the sample aspect ratio of the sourced video.
8376 Set the video duration of the sourced video. The accepted syntax is:
8378 [-]HH[:MM[:SS[.m...]]]
8381 See also the function @code{av_parse_time()}.
8383 If not specified, or the expressed duration is negative, the video is
8384 supposed to be generated forever.
8387 Set the number of decimals to show in the timestamp, only available in the
8388 @code{testsrc} source.
8390 The displayed timestamp value will correspond to the original
8391 timestamp value multiplied by the power of 10 of the specified
8392 value. Default value is 0.
8395 For example the following:
8397 testsrc=duration=5.3:size=qcif:rate=10
8400 will generate a video with a duration of 5.3 seconds, with size
8401 176x144 and a frame rate of 10 frames per second.
8403 The following graph description will generate a red source
8404 with an opacity of 0.2, with size "qcif" and a frame rate of 10
8407 color=c=red@@0.2:s=qcif:r=10
8410 If the input content is to be ignored, @code{nullsrc} can be used. The
8411 following command generates noise in the luminance plane by employing
8412 the @code{geq} filter:
8414 nullsrc=s=256x256, geq=random(1)*255:128:128
8417 @subsection Commands
8419 The @code{color} source supports the following commands:
8423 Set the color of the created image. Accepts the same syntax of the
8424 corresponding @option{color} option.
8427 @c man end VIDEO SOURCES
8429 @chapter Video Sinks
8430 @c man begin VIDEO SINKS
8432 Below is a description of the currently available video sinks.
8436 Buffer video frames, and make them available to the end of the filter
8439 This sink is mainly intended for a programmatic use, in particular
8440 through the interface defined in @file{libavfilter/buffersink.h}
8441 or the options system.
8443 It accepts a pointer to an AVBufferSinkContext structure, which
8444 defines the incoming buffers' formats, to be passed as the opaque
8445 parameter to @code{avfilter_init_filter} for initialization.
8449 Null video sink, do absolutely nothing with the input video. It is
8450 mainly useful as a template and to be employed in analysis / debugging
8453 @c man end VIDEO SINKS
8455 @chapter Multimedia Filters
8456 @c man begin MULTIMEDIA FILTERS
8458 Below is a description of the currently available multimedia filters.
8460 @section avectorscope
8462 Convert input audio to a video output, representing the audio vector
8465 The filter is used to measure the difference between channels of stereo
8466 audio stream. A monoaural signal, consisting of identical left and right
8467 signal, results in straight vertical line. Any stereo separation is visible
8468 as a deviation from this line, creating a Lissajous figure.
8469 If the straight (or deviation from it) but horizontal line appears this
8470 indicates that the left and right channels are out of phase.
8472 The filter accepts the following options:
8476 Set the vectorscope mode.
8478 Available values are:
8481 Lissajous rotated by 45 degrees.
8484 Same as above but not rotated.
8487 Default value is @samp{lissajous}.
8490 Set the video size for the output. Default value is @code{400x400}.
8493 Set the output frame rate. Default value is @code{25}.
8498 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
8499 Allowed range is @code{[0, 255]}.
8504 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
8505 Allowed range is @code{[0, 255]}.
8508 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
8511 @subsection Examples
8515 Complete example using @command{ffplay}:
8517 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
8518 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
8524 Concatenate audio and video streams, joining them together one after the
8527 The filter works on segments of synchronized video and audio streams. All
8528 segments must have the same number of streams of each type, and that will
8529 also be the number of streams at output.
8531 The filter accepts the following options:
8536 Set the number of segments. Default is 2.
8539 Set the number of output video streams, that is also the number of video
8540 streams in each segment. Default is 1.
8543 Set the number of output audio streams, that is also the number of video
8544 streams in each segment. Default is 0.
8547 Activate unsafe mode: do not fail if segments have a different format.
8551 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
8552 @var{a} audio outputs.
8554 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
8555 segment, in the same order as the outputs, then the inputs for the second
8558 Related streams do not always have exactly the same duration, for various
8559 reasons including codec frame size or sloppy authoring. For that reason,
8560 related synchronized streams (e.g. a video and its audio track) should be
8561 concatenated at once. The concat filter will use the duration of the longest
8562 stream in each segment (except the last one), and if necessary pad shorter
8563 audio streams with silence.
8565 For this filter to work correctly, all segments must start at timestamp 0.
8567 All corresponding streams must have the same parameters in all segments; the
8568 filtering system will automatically select a common pixel format for video
8569 streams, and a common sample format, sample rate and channel layout for
8570 audio streams, but other settings, such as resolution, must be converted
8571 explicitly by the user.
8573 Different frame rates are acceptable but will result in variable frame rate
8574 at output; be sure to configure the output file to handle it.
8576 @subsection Examples
8580 Concatenate an opening, an episode and an ending, all in bilingual version
8581 (video in stream 0, audio in streams 1 and 2):
8583 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
8584 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
8585 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
8586 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
8590 Concatenate two parts, handling audio and video separately, using the
8591 (a)movie sources, and adjusting the resolution:
8593 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
8594 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
8595 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
8597 Note that a desync will happen at the stitch if the audio and video streams
8598 do not have exactly the same duration in the first file.
8604 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
8605 it unchanged. By default, it logs a message at a frequency of 10Hz with the
8606 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
8607 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
8609 The filter also has a video output (see the @var{video} option) with a real
8610 time graph to observe the loudness evolution. The graphic contains the logged
8611 message mentioned above, so it is not printed anymore when this option is set,
8612 unless the verbose logging is set. The main graphing area contains the
8613 short-term loudness (3 seconds of analysis), and the gauge on the right is for
8614 the momentary loudness (400 milliseconds).
8616 More information about the Loudness Recommendation EBU R128 on
8617 @url{http://tech.ebu.ch/loudness}.
8619 The filter accepts the following options:
8624 Activate the video output. The audio stream is passed unchanged whether this
8625 option is set or no. The video stream will be the first output stream if
8626 activated. Default is @code{0}.
8629 Set the video size. This option is for video only. Default and minimum
8630 resolution is @code{640x480}.
8633 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
8634 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
8635 other integer value between this range is allowed.
8638 Set metadata injection. If set to @code{1}, the audio input will be segmented
8639 into 100ms output frames, each of them containing various loudness information
8640 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
8642 Default is @code{0}.
8645 Force the frame logging level.
8647 Available values are:
8650 information logging level
8652 verbose logging level
8655 By default, the logging level is set to @var{info}. If the @option{video} or
8656 the @option{metadata} options are set, it switches to @var{verbose}.
8659 @subsection Examples
8663 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
8665 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
8669 Run an analysis with @command{ffmpeg}:
8671 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
8675 @section interleave, ainterleave
8677 Temporally interleave frames from several inputs.
8679 @code{interleave} works with video inputs, @code{ainterleave} with audio.
8681 These filters read frames from several inputs and send the oldest
8682 queued frame to the output.
8684 Input streams must have a well defined, monotonically increasing frame
8687 In order to submit one frame to output, these filters need to enqueue
8688 at least one frame for each input, so they cannot work in case one
8689 input is not yet terminated and will not receive incoming frames.
8691 For example consider the case when one input is a @code{select} filter
8692 which always drop input frames. The @code{interleave} filter will keep
8693 reading from that input, but it will never be able to send new frames
8694 to output until the input will send an end-of-stream signal.
8696 Also, depending on inputs synchronization, the filters will drop
8697 frames in case one input receives more frames than the other ones, and
8698 the queue is already filled.
8700 These filters accept the following options:
8704 Set the number of different inputs, it is 2 by default.
8707 @subsection Examples
8711 Interleave frames belonging to different streams using @command{ffmpeg}:
8713 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
8717 Add flickering blur effect:
8719 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
8723 @section perms, aperms
8725 Set read/write permissions for the output frames.
8727 These filters are mainly aimed at developers to test direct path in the
8728 following filter in the filtergraph.
8730 The filters accept the following options:
8734 Select the permissions mode.
8736 It accepts the following values:
8739 Do nothing. This is the default.
8741 Set all the output frames read-only.
8743 Set all the output frames directly writable.
8745 Make the frame read-only if writable, and writable if read-only.
8747 Set each output frame read-only or writable randomly.
8751 Set the seed for the @var{random} mode, must be an integer included between
8752 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
8753 @code{-1}, the filter will try to use a good random seed on a best effort
8757 Note: in case of auto-inserted filter between the permission filter and the
8758 following one, the permission might not be received as expected in that
8759 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
8760 perms/aperms filter can avoid this problem.
8762 @section select, aselect
8764 Select frames to pass in output.
8766 This filter accepts the following options:
8771 Set expression, which is evaluated for each input frame.
8773 If the expression is evaluated to zero, the frame is discarded.
8775 If the evaluation result is negative or NaN, the frame is sent to the
8776 first output; otherwise it is sent to the output with index
8777 @code{ceil(val)-1}, assuming that the input index starts from 0.
8779 For example a value of @code{1.2} corresponds to the output with index
8780 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
8783 Set the number of outputs. The output to which to send the selected
8784 frame is based on the result of the evaluation. Default value is 1.
8787 The expression can contain the following constants:
8791 the sequential number of the filtered frame, starting from 0
8794 the sequential number of the selected frame, starting from 0
8796 @item prev_selected_n
8797 the sequential number of the last selected frame, NAN if undefined
8800 timebase of the input timestamps
8803 the PTS (Presentation TimeStamp) of the filtered video frame,
8804 expressed in @var{TB} units, NAN if undefined
8807 the PTS (Presentation TimeStamp) of the filtered video frame,
8808 expressed in seconds, NAN if undefined
8811 the PTS of the previously filtered video frame, NAN if undefined
8813 @item prev_selected_pts
8814 the PTS of the last previously filtered video frame, NAN if undefined
8816 @item prev_selected_t
8817 the PTS of the last previously selected video frame, NAN if undefined
8820 the PTS of the first video frame in the video, NAN if undefined
8823 the time of the first video frame in the video, NAN if undefined
8825 @item pict_type @emph{(video only)}
8826 the type of the filtered frame, can assume one of the following
8838 @item interlace_type @emph{(video only)}
8839 the frame interlace type, can assume one of the following values:
8842 the frame is progressive (not interlaced)
8844 the frame is top-field-first
8846 the frame is bottom-field-first
8849 @item consumed_sample_n @emph{(audio only)}
8850 the number of selected samples before the current frame
8852 @item samples_n @emph{(audio only)}
8853 the number of samples in the current frame
8855 @item sample_rate @emph{(audio only)}
8856 the input sample rate
8859 1 if the filtered frame is a key-frame, 0 otherwise
8862 the position in the file of the filtered frame, -1 if the information
8863 is not available (e.g. for synthetic video)
8865 @item scene @emph{(video only)}
8866 value between 0 and 1 to indicate a new scene; a low value reflects a low
8867 probability for the current frame to introduce a new scene, while a higher
8868 value means the current frame is more likely to be one (see the example below)
8872 The default value of the select expression is "1".
8874 @subsection Examples
8878 Select all frames in input:
8883 The example above is the same as:
8895 Select only I-frames:
8897 select='eq(pict_type\,I)'
8901 Select one frame every 100:
8903 select='not(mod(n\,100))'
8907 Select only frames contained in the 10-20 time interval:
8909 select='gte(t\,10)*lte(t\,20)'
8913 Select only I frames contained in the 10-20 time interval:
8915 select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
8919 Select frames with a minimum distance of 10 seconds:
8921 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
8925 Use aselect to select only audio frames with samples number > 100:
8927 aselect='gt(samples_n\,100)'
8931 Create a mosaic of the first scenes:
8933 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
8936 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
8940 Send even and odd frames to separate outputs, and compose them:
8942 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
8946 @section sendcmd, asendcmd
8948 Send commands to filters in the filtergraph.
8950 These filters read commands to be sent to other filters in the
8953 @code{sendcmd} must be inserted between two video filters,
8954 @code{asendcmd} must be inserted between two audio filters, but apart
8955 from that they act the same way.
8957 The specification of commands can be provided in the filter arguments
8958 with the @var{commands} option, or in a file specified by the
8959 @var{filename} option.
8961 These filters accept the following options:
8964 Set the commands to be read and sent to the other filters.
8966 Set the filename of the commands to be read and sent to the other
8970 @subsection Commands syntax
8972 A commands description consists of a sequence of interval
8973 specifications, comprising a list of commands to be executed when a
8974 particular event related to that interval occurs. The occurring event
8975 is typically the current frame time entering or leaving a given time
8978 An interval is specified by the following syntax:
8980 @var{START}[-@var{END}] @var{COMMANDS};
8983 The time interval is specified by the @var{START} and @var{END} times.
8984 @var{END} is optional and defaults to the maximum time.
8986 The current frame time is considered within the specified interval if
8987 it is included in the interval [@var{START}, @var{END}), that is when
8988 the time is greater or equal to @var{START} and is lesser than
8991 @var{COMMANDS} consists of a sequence of one or more command
8992 specifications, separated by ",", relating to that interval. The
8993 syntax of a command specification is given by:
8995 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
8998 @var{FLAGS} is optional and specifies the type of events relating to
8999 the time interval which enable sending the specified command, and must
9000 be a non-null sequence of identifier flags separated by "+" or "|" and
9001 enclosed between "[" and "]".
9003 The following flags are recognized:
9006 The command is sent when the current frame timestamp enters the
9007 specified interval. In other words, the command is sent when the
9008 previous frame timestamp was not in the given interval, and the
9012 The command is sent when the current frame timestamp leaves the
9013 specified interval. In other words, the command is sent when the
9014 previous frame timestamp was in the given interval, and the
9018 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
9021 @var{TARGET} specifies the target of the command, usually the name of
9022 the filter class or a specific filter instance name.
9024 @var{COMMAND} specifies the name of the command for the target filter.
9026 @var{ARG} is optional and specifies the optional list of argument for
9027 the given @var{COMMAND}.
9029 Between one interval specification and another, whitespaces, or
9030 sequences of characters starting with @code{#} until the end of line,
9031 are ignored and can be used to annotate comments.
9033 A simplified BNF description of the commands specification syntax
9036 @var{COMMAND_FLAG} ::= "enter" | "leave"
9037 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
9038 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
9039 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
9040 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
9041 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
9044 @subsection Examples
9048 Specify audio tempo change at second 4:
9050 asendcmd=c='4.0 atempo tempo 1.5',atempo
9054 Specify a list of drawtext and hue commands in a file.
9056 # show text in the interval 5-10
9057 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
9058 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
9060 # desaturate the image in the interval 15-20
9061 15.0-20.0 [enter] hue s 0,
9062 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
9064 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
9066 # apply an exponential saturation fade-out effect, starting from time 25
9067 25 [enter] hue s exp(25-t)
9070 A filtergraph allowing to read and process the above command list
9071 stored in a file @file{test.cmd}, can be specified with:
9073 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
9078 @section setpts, asetpts
9080 Change the PTS (presentation timestamp) of the input frames.
9082 @code{setpts} works on video frames, @code{asetpts} on audio frames.
9084 This filter accepts the following options:
9089 The expression which is evaluated for each frame to construct its timestamp.
9093 The expression is evaluated through the eval API and can contain the following
9098 frame rate, only defined for constant frame-rate video
9101 the presentation timestamp in input
9104 the count of the input frame for video or the number of consumed samples,
9105 not including the current frame for audio, starting from 0.
9107 @item NB_CONSUMED_SAMPLES
9108 the number of consumed samples, not including the current frame (only
9112 the number of samples in the current frame (only audio)
9114 @item SAMPLE_RATE, SR
9118 the PTS of the first frame
9121 the time in seconds of the first frame
9124 tell if the current frame is interlaced
9127 the time in seconds of the current frame
9133 original position in the file of the frame, or undefined if undefined
9134 for the current frame
9140 previous input time in seconds
9146 previous output time in seconds
9149 wallclock (RTC) time in microseconds. This is deprecated, use time(0)
9153 wallclock (RTC) time at the start of the movie in microseconds
9156 @subsection Examples
9160 Start counting PTS from zero
9166 Apply fast motion effect:
9172 Apply slow motion effect:
9178 Set fixed rate of 25 frames per second:
9184 Set fixed rate 25 fps with some jitter:
9186 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
9190 Apply an offset of 10 seconds to the input PTS:
9196 Generate timestamps from a "live source" and rebase onto the current timebase:
9198 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
9202 Generate timestamps by counting samples:
9209 @section settb, asettb
9211 Set the timebase to use for the output frames timestamps.
9212 It is mainly useful for testing timebase configuration.
9214 This filter accepts the following options:
9219 The expression which is evaluated into the output timebase.
9223 The value for @option{tb} is an arithmetic expression representing a
9224 rational. The expression can contain the constants "AVTB" (the default
9225 timebase), "intb" (the input timebase) and "sr" (the sample rate,
9226 audio only). Default value is "intb".
9228 @subsection Examples
9232 Set the timebase to 1/25:
9238 Set the timebase to 1/10:
9244 Set the timebase to 1001/1000:
9250 Set the timebase to 2*intb:
9256 Set the default timebase value:
9262 @section showspectrum
9264 Convert input audio to a video output, representing the audio frequency
9267 The filter accepts the following options:
9271 Specify the video size for the output. Default value is @code{640x512}.
9274 Specify if the spectrum should slide along the window. Default value is
9278 Specify display mode.
9280 It accepts the following values:
9283 all channels are displayed in the same row
9285 all channels are displayed in separate rows
9288 Default value is @samp{combined}.
9291 Specify display color mode.
9293 It accepts the following values:
9296 each channel is displayed in a separate color
9298 each channel is is displayed using the same color scheme
9301 Default value is @samp{channel}.
9304 Specify scale used for calculating intensity color values.
9306 It accepts the following values:
9311 square root, default
9318 Default value is @samp{sqrt}.
9321 Set saturation modifier for displayed colors. Negative values provide
9322 alternative color scheme. @code{0} is no saturation at all.
9323 Saturation must be in [-10.0, 10.0] range.
9324 Default value is @code{1}.
9327 The usage is very similar to the showwaves filter; see the examples in that
9330 @subsection Examples
9334 Large window with logarithmic color scaling:
9336 showspectrum=s=1280x480:scale=log
9340 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
9342 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9343 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
9349 Convert input audio to a video output, representing the samples waves.
9351 The filter accepts the following options:
9355 Specify the video size for the output. Default value is "600x240".
9360 Available values are:
9363 Draw a point for each sample.
9366 Draw a vertical line for each sample.
9369 Default value is @code{point}.
9372 Set the number of samples which are printed on the same column. A
9373 larger value will decrease the frame rate. Must be a positive
9374 integer. This option can be set only if the value for @var{rate}
9375 is not explicitly specified.
9378 Set the (approximate) output frame rate. This is done by setting the
9379 option @var{n}. Default value is "25".
9383 @subsection Examples
9387 Output the input file audio and the corresponding video representation
9390 amovie=a.mp3,asplit[out0],showwaves[out1]
9394 Create a synthetic signal and show it with showwaves, forcing a
9395 frame rate of 30 frames per second:
9397 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
9401 @section split, asplit
9403 Split input into several identical outputs.
9405 @code{asplit} works with audio input, @code{split} with video.
9407 The filter accepts a single parameter which specifies the number of outputs. If
9408 unspecified, it defaults to 2.
9410 @subsection Examples
9414 Create two separate outputs from the same input:
9416 [in] split [out0][out1]
9420 To create 3 or more outputs, you need to specify the number of
9423 [in] asplit=3 [out0][out1][out2]
9427 Create two separate outputs from the same input, one cropped and
9430 [in] split [splitout1][splitout2];
9431 [splitout1] crop=100:100:0:0 [cropout];
9432 [splitout2] pad=200:200:100:100 [padout];
9436 Create 5 copies of the input audio with @command{ffmpeg}:
9438 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
9444 Receive commands sent through a libzmq client, and forward them to
9445 filters in the filtergraph.
9447 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
9448 must be inserted between two video filters, @code{azmq} between two
9451 To enable these filters you need to install the libzmq library and
9452 headers and configure FFmpeg with @code{--enable-libzmq}.
9454 For more information about libzmq see:
9455 @url{http://www.zeromq.org/}
9457 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
9458 receives messages sent through a network interface defined by the
9459 @option{bind_address} option.
9461 The received message must be in the form:
9463 @var{TARGET} @var{COMMAND} [@var{ARG}]
9466 @var{TARGET} specifies the target of the command, usually the name of
9467 the filter class or a specific filter instance name.
9469 @var{COMMAND} specifies the name of the command for the target filter.
9471 @var{ARG} is optional and specifies the optional argument list for the
9472 given @var{COMMAND}.
9474 Upon reception, the message is processed and the corresponding command
9475 is injected into the filtergraph. Depending on the result, the filter
9476 will send a reply to the client, adopting the format:
9478 @var{ERROR_CODE} @var{ERROR_REASON}
9482 @var{MESSAGE} is optional.
9484 @subsection Examples
9486 Look at @file{tools/zmqsend} for an example of a zmq client which can
9487 be used to send commands processed by these filters.
9489 Consider the following filtergraph generated by @command{ffplay}
9491 ffplay -dumpgraph 1 -f lavfi "
9492 color=s=100x100:c=red [l];
9493 color=s=100x100:c=blue [r];
9494 nullsrc=s=200x100, zmq [bg];
9495 [bg][l] overlay [bg+l];
9496 [bg+l][r] overlay=x=100 "
9499 To change the color of the left side of the video, the following
9500 command can be used:
9502 echo Parsed_color_0 c yellow | tools/zmqsend
9505 To change the right side:
9507 echo Parsed_color_1 c pink | tools/zmqsend
9510 @c man end MULTIMEDIA FILTERS
9512 @chapter Multimedia Sources
9513 @c man begin MULTIMEDIA SOURCES
9515 Below is a description of the currently available multimedia sources.
9519 This is the same as @ref{movie} source, except it selects an audio
9525 Read audio and/or video stream(s) from a movie container.
9527 This filter accepts the following options:
9531 The name of the resource to read (not necessarily a file but also a device or a
9532 stream accessed through some protocol).
9534 @item format_name, f
9535 Specifies the format assumed for the movie to read, and can be either
9536 the name of a container or an input device. If not specified the
9537 format is guessed from @var{movie_name} or by probing.
9539 @item seek_point, sp
9540 Specifies the seek point in seconds, the frames will be output
9541 starting from this seek point, the parameter is evaluated with
9542 @code{av_strtod} so the numerical value may be suffixed by an IS
9543 postfix. Default value is "0".
9546 Specifies the streams to read. Several streams can be specified,
9547 separated by "+". The source will then have as many outputs, in the
9548 same order. The syntax is explained in the ``Stream specifiers''
9549 section in the ffmpeg manual. Two special names, "dv" and "da" specify
9550 respectively the default (best suited) video and audio stream. Default
9551 is "dv", or "da" if the filter is called as "amovie".
9553 @item stream_index, si
9554 Specifies the index of the video stream to read. If the value is -1,
9555 the best suited video stream will be automatically selected. Default
9556 value is "-1". Deprecated. If the filter is called "amovie", it will select
9557 audio instead of video.
9560 Specifies how many times to read the stream in sequence.
9561 If the value is less than 1, the stream will be read again and again.
9562 Default value is "1".
9564 Note that when the movie is looped the source timestamps are not
9565 changed, so it will generate non monotonically increasing timestamps.
9568 This filter allows to overlay a second video on top of main input of
9569 a filtergraph as shown in this graph:
9571 input -----------> deltapts0 --> overlay --> output
9574 movie --> scale--> deltapts1 -------+
9577 @subsection Examples
9581 Skip 3.2 seconds from the start of the avi file in.avi, and overlay it
9582 on top of the input labelled as "in":
9584 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
9585 [in] setpts=PTS-STARTPTS [main];
9586 [main][over] overlay=16:16 [out]
9590 Read from a video4linux2 device, and overlay it on top of the input
9593 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
9594 [in] setpts=PTS-STARTPTS [main];
9595 [main][over] overlay=16:16 [out]
9599 Read the first video stream and the audio stream with id 0x81 from
9600 dvd.vob; the video is connected to the pad named "video" and the audio is
9601 connected to the pad named "audio":
9603 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
9607 @c man end MULTIMEDIA SOURCES