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 Delay one or more audio channels.
354 Samples in delayed channel are filled with silence.
356 The filter accepts the following option:
360 Set list of delays in milliseconds for each channel separated by '|'.
361 At least one delay greater than 0 should be provided.
362 Unused delays will be silently ignored. If number of given delays is
363 smaller than number of channels all remaining channels will not be delayed.
370 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
371 the second channel (and any other channels that may be present) unchanged.
379 Apply echoing to the input audio.
381 Echoes are reflected sound and can occur naturally amongst mountains
382 (and sometimes large buildings) when talking or shouting; digital echo
383 effects emulate this behaviour and are often used to help fill out the
384 sound of a single instrument or vocal. The time difference between the
385 original signal and the reflection is the @code{delay}, and the
386 loudness of the reflected signal is the @code{decay}.
387 Multiple echoes can have different delays and decays.
389 A description of the accepted parameters follows.
393 Set input gain of reflected signal. Default is @code{0.6}.
396 Set output gain of reflected signal. Default is @code{0.3}.
399 Set list of time intervals in milliseconds between original signal and reflections
400 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
401 Default is @code{1000}.
404 Set list of loudnesses of reflected signals separated by '|'.
405 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
406 Default is @code{0.5}.
413 Make it sound as if there are twice as many instruments as are actually playing:
415 aecho=0.8:0.88:60:0.4
419 If delay is very short, then it sound like a (metallic) robot playing music:
425 A longer delay will sound like an open air concert in the mountains:
427 aecho=0.8:0.9:1000:0.3
431 Same as above but with one more mountain:
433 aecho=0.8:0.9:1000|1800:0.3|0.25
439 Apply fade-in/out effect to input audio.
441 A description of the accepted parameters follows.
445 Specify the effect type, can be either @code{in} for fade-in, or
446 @code{out} for a fade-out effect. Default is @code{in}.
448 @item start_sample, ss
449 Specify the number of the start sample for starting to apply the fade
450 effect. Default is 0.
453 Specify the number of samples for which the fade effect has to last. At
454 the end of the fade-in effect the output audio will have the same
455 volume as the input audio, at the end of the fade-out transition
456 the output audio will be silence. Default is 44100.
459 Specify time for starting to apply the fade effect. Default is 0.
460 The accepted syntax is:
462 [-]HH[:MM[:SS[.m...]]]
465 See also the function @code{av_parse_time()}.
466 If set this option is used instead of @var{start_sample} one.
469 Specify the duration for which the fade effect has to last. Default is 0.
470 The accepted syntax is:
472 [-]HH[:MM[:SS[.m...]]]
475 See also the function @code{av_parse_time()}.
476 At the end of the fade-in effect the output audio will have the same
477 volume as the input audio, at the end of the fade-out transition
478 the output audio will be silence.
479 If set this option is used instead of @var{nb_samples} one.
482 Set curve for fade transition.
484 It accepts the following values:
487 select triangular, linear slope (default)
489 select quarter of sine wave
491 select half of sine wave
493 select exponential sine wave
497 select inverted parabola
513 Fade in first 15 seconds of audio:
519 Fade out last 25 seconds of a 900 seconds audio:
521 afade=t=out:st=875:d=25
528 Set output format constraints for the input audio. The framework will
529 negotiate the most appropriate format to minimize conversions.
531 The filter accepts the following named parameters:
535 A '|'-separated list of requested sample formats.
538 A '|'-separated list of requested sample rates.
540 @item channel_layouts
541 A '|'-separated list of requested channel layouts.
545 If a parameter is omitted, all values are allowed.
547 For example to force the output to either unsigned 8-bit or signed 16-bit stereo:
549 aformat=sample_fmts=u8|s16:channel_layouts=stereo
554 Apply a two-pole all-pass filter with central frequency (in Hz)
555 @var{frequency}, and filter-width @var{width}.
556 An all-pass filter changes the audio's frequency to phase relationship
557 without changing its frequency to amplitude relationship.
559 The filter accepts the following options:
566 Set method to specify band-width of filter.
579 Specify the band-width of a filter in width_type units.
584 Merge two or more audio streams into a single multi-channel stream.
586 The filter accepts the following options:
591 Set the number of inputs. Default is 2.
595 If the channel layouts of the inputs are disjoint, and therefore compatible,
596 the channel layout of the output will be set accordingly and the channels
597 will be reordered as necessary. If the channel layouts of the inputs are not
598 disjoint, the output will have all the channels of the first input then all
599 the channels of the second input, in that order, and the channel layout of
600 the output will be the default value corresponding to the total number of
603 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
604 is FC+BL+BR, then the output will be in 5.1, with the channels in the
605 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
606 first input, b1 is the first channel of the second input).
608 On the other hand, if both input are in stereo, the output channels will be
609 in the default order: a1, a2, b1, b2, and the channel layout will be
610 arbitrarily set to 4.0, which may or may not be the expected value.
612 All inputs must have the same sample rate, and format.
614 If inputs do not have the same duration, the output will stop with the
621 Merge two mono files into a stereo stream:
623 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
627 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
629 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
635 Mixes multiple audio inputs into a single output.
639 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
641 will mix 3 input audio streams to a single output with the same duration as the
642 first input and a dropout transition time of 3 seconds.
644 The filter accepts the following named parameters:
648 Number of inputs. If unspecified, it defaults to 2.
651 How to determine the end-of-stream.
655 Duration of longest input. (default)
658 Duration of shortest input.
661 Duration of first input.
665 @item dropout_transition
666 Transition time, in seconds, for volume renormalization when an input
667 stream ends. The default value is 2 seconds.
673 Pass the audio source unchanged to the output.
677 Pad the end of a audio stream with silence, this can be used together with
678 -shortest to extend audio streams to the same length as the video stream.
681 Add a phasing effect to the input audio.
683 A phaser filter creates series of peaks and troughs in the frequency spectrum.
684 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
686 A description of the accepted parameters follows.
690 Set input gain. Default is 0.4.
693 Set output gain. Default is 0.74
696 Set delay in milliseconds. Default is 3.0.
699 Set decay. Default is 0.4.
702 Set modulation speed in Hz. Default is 0.5.
705 Set modulation type. Default is triangular.
707 It accepts the following values:
717 Resample the input audio to the specified parameters, using the
718 libswresample library. If none are specified then the filter will
719 automatically convert between its input and output.
721 This filter is also able to stretch/squeeze the audio data to make it match
722 the timestamps or to inject silence / cut out audio to make it match the
723 timestamps, do a combination of both or do neither.
725 The filter accepts the syntax
726 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
727 expresses a sample rate and @var{resampler_options} is a list of
728 @var{key}=@var{value} pairs, separated by ":". See the
729 ffmpeg-resampler manual for the complete list of supported options.
735 Resample the input audio to 44100Hz:
741 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
742 samples per second compensation:
748 @section asetnsamples
750 Set the number of samples per each output audio frame.
752 The last output packet may contain a different number of samples, as
753 the filter will flush all the remaining samples when the input audio
756 The filter accepts the following options:
760 @item nb_out_samples, n
761 Set the number of frames per each output audio frame. The number is
762 intended as the number of samples @emph{per each channel}.
763 Default value is 1024.
766 If set to 1, the filter will pad the last audio frame with zeroes, so
767 that the last frame will contain the same number of samples as the
768 previous ones. Default value is 1.
771 For example, to set the number of per-frame samples to 1234 and
772 disable padding for the last frame, use:
774 asetnsamples=n=1234:p=0
779 Set the sample rate without altering the PCM data.
780 This will result in a change of speed and pitch.
782 The filter accepts the following options:
786 Set the output sample rate. Default is 44100 Hz.
791 Show a line containing various information for each input audio frame.
792 The input audio is not modified.
794 The shown line contains a sequence of key/value pairs of the form
795 @var{key}:@var{value}.
797 A description of each shown parameter follows:
801 sequential number of the input frame, starting from 0
804 Presentation timestamp of the input frame, in time base units; the time base
805 depends on the filter input pad, and is usually 1/@var{sample_rate}.
808 presentation timestamp of the input frame in seconds
811 position of the frame in the input stream, -1 if this information in
812 unavailable and/or meaningless (for example in case of synthetic audio)
821 sample rate for the audio frame
824 number of samples (per channel) in the frame
827 Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio
828 the data is treated as if all the planes were concatenated.
830 @item plane_checksums
831 A list of Adler-32 checksums for each data plane.
836 Display time domain statistical information about the audio channels.
837 Statistics are calculated and displayed for each audio channel and,
838 where applicable, an overall figure is also given.
840 The filter accepts the following option:
843 Short window length in seconds, used for peak and trough RMS measurement.
844 Default is @code{0.05} (50 miliseconds). Allowed range is @code{[0.1 - 10]}.
847 A description of each shown parameter follows:
851 Mean amplitude displacement from zero.
854 Minimal sample level.
857 Maximal sample level.
861 Standard peak and RMS level measured in dBFS.
865 Peak and trough values for RMS level measured over a short window.
868 Standard ratio of peak to RMS level (note: not in dB).
871 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
872 (i.e. either @var{Min level} or @var{Max level}).
875 Number of occasions (not the number of samples) that the signal attained either
876 @var{Min level} or @var{Max level}.
881 Forward two audio streams and control the order the buffers are forwarded.
883 The filter accepts the following options:
887 Set the expression deciding which stream should be
888 forwarded next: if the result is negative, the first stream is forwarded; if
889 the result is positive or zero, the second stream is forwarded. It can use
890 the following variables:
894 number of buffers forwarded so far on each stream
896 number of samples forwarded so far on each stream
898 current timestamp of each stream
901 The default value is @code{t1-t2}, which means to always forward the stream
902 that has a smaller timestamp.
907 Stress-test @code{amerge} by randomly sending buffers on the wrong
908 input, while avoiding too much of a desynchronization:
910 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
911 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
917 Synchronize audio data with timestamps by squeezing/stretching it and/or
918 dropping samples/adding silence when needed.
920 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
922 The filter accepts the following named parameters:
926 Enable stretching/squeezing the data to make it match the timestamps. Disabled
927 by default. When disabled, time gaps are covered with silence.
930 Minimum difference between timestamps and audio data (in seconds) to trigger
931 adding/dropping samples. Default value is 0.1. If you get non-perfect sync with
932 this filter, try setting this parameter to 0.
935 Maximum compensation in samples per second. Relevant only with compensate=1.
939 Assume the first pts should be this value. The time base is 1 / sample rate.
940 This allows for padding/trimming at the start of stream. By default, no
941 assumption is made about the first frame's expected pts, so no padding or
942 trimming is done. For example, this could be set to 0 to pad the beginning with
943 silence if an audio stream starts after the video stream or to trim any samples
944 with a negative pts due to encoder delay.
952 The filter accepts exactly one parameter, the audio tempo. If not
953 specified then the filter will assume nominal 1.0 tempo. Tempo must
954 be in the [0.5, 2.0] range.
960 Slow down audio to 80% tempo:
966 To speed up audio to 125% tempo:
974 Trim the input so that the output contains one continuous subpart of the input.
976 This filter accepts the following options:
979 Specify time of the start of the kept section, i.e. the audio sample
980 with the timestamp @var{start} will be the first sample in the output.
983 Specify time of the first audio sample that will be dropped, i.e. the
984 audio sample immediately preceding the one with the timestamp @var{end} will be
985 the last sample in the output.
988 Same as @var{start}, except this option sets the start timestamp in samples
992 Same as @var{end}, except this option sets the end timestamp in samples instead
996 Specify maximum duration of the output.
999 Number of the first sample that should be passed to output.
1002 Number of the first sample that should be dropped.
1005 @option{start}, @option{end}, @option{duration} are expressed as time
1006 duration specifications, check the "Time duration" section in the
1007 ffmpeg-utils manual.
1009 Note that the first two sets of the start/end options and the @option{duration}
1010 option look at the frame timestamp, while the _sample options simply count the
1011 samples that pass through the filter. So start/end_pts and start/end_sample will
1012 give different results when the timestamps are wrong, inexact or do not start at
1013 zero. Also note that this filter does not modify the timestamps. If you wish
1014 that the output timestamps start at zero, insert the asetpts filter after the
1017 If multiple start or end options are set, this filter tries to be greedy and
1018 keep all samples that match at least one of the specified constraints. To keep
1019 only the part that matches all the constraints at once, chain multiple atrim
1022 The defaults are such that all the input is kept. So it is possible to set e.g.
1023 just the end values to keep everything before the specified time.
1028 drop everything except the second minute of input
1030 ffmpeg -i INPUT -af atrim=60:120
1034 keep only the first 1000 samples
1036 ffmpeg -i INPUT -af atrim=end_sample=1000
1043 Apply a two-pole Butterworth band-pass filter with central
1044 frequency @var{frequency}, and (3dB-point) band-width width.
1045 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1046 instead of the default: constant 0dB peak gain.
1047 The filter roll off at 6dB per octave (20dB per decade).
1049 The filter accepts the following options:
1053 Set the filter's central frequency. Default is @code{3000}.
1056 Constant skirt gain if set to 1. Defaults to 0.
1059 Set method to specify band-width of filter.
1072 Specify the band-width of a filter in width_type units.
1077 Apply a two-pole Butterworth band-reject filter with central
1078 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1079 The filter roll off at 6dB per octave (20dB per decade).
1081 The filter accepts the following options:
1085 Set the filter's central frequency. Default is @code{3000}.
1088 Set method to specify band-width of filter.
1101 Specify the band-width of a filter in width_type units.
1106 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1107 shelving filter with a response similar to that of a standard
1108 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1110 The filter accepts the following options:
1114 Give the gain at 0 Hz. Its useful range is about -20
1115 (for a large cut) to +20 (for a large boost).
1116 Beware of clipping when using a positive gain.
1119 Set the filter's central frequency and so can be used
1120 to extend or reduce the frequency range to be boosted or cut.
1121 The default value is @code{100} Hz.
1124 Set method to specify band-width of filter.
1137 Determine how steep is the filter's shelf transition.
1142 Apply a biquad IIR filter with the given coefficients.
1143 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1144 are the numerator and denominator coefficients respectively.
1148 Remap input channels to new locations.
1150 This filter accepts the following named parameters:
1152 @item channel_layout
1153 Channel layout of the output stream.
1156 Map channels from input to output. The argument is a '|'-separated list of
1157 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1158 @var{in_channel} form. @var{in_channel} can be either the name of the input
1159 channel (e.g. FL for front left) or its index in the input channel layout.
1160 @var{out_channel} is the name of the output channel or its index in the output
1161 channel layout. If @var{out_channel} is not given then it is implicitly an
1162 index, starting with zero and increasing by one for each mapping.
1165 If no mapping is present, the filter will implicitly map input channels to
1166 output channels preserving index.
1168 For example, assuming a 5.1+downmix input MOV file
1170 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1172 will create an output WAV file tagged as stereo from the downmix channels of
1175 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1177 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1180 @section channelsplit
1182 Split each channel in input audio stream into a separate output stream.
1184 This filter accepts the following named parameters:
1186 @item channel_layout
1187 Channel layout of the input stream. Default is "stereo".
1190 For example, assuming a stereo input MP3 file
1192 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1194 will create an output Matroska file with two audio streams, one containing only
1195 the left channel and the other the right channel.
1197 To split a 5.1 WAV file into per-channel files
1199 ffmpeg -i in.wav -filter_complex
1200 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1201 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1202 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1208 Compress or expand audio dynamic range.
1210 A description of the accepted options follows.
1215 Set list of times in seconds for each channel over which the instantaneous
1216 level of the input signal is averaged to determine its volume.
1217 @option{attacks} refers to increase of volume and @option{decays} refers
1218 to decrease of volume.
1219 For most situations, the attack time (response to the audio getting louder)
1220 should be shorter than the decay time because the human ear is more sensitive
1221 to sudden loud audio than sudden soft audio.
1222 Typical value for attack is @code{0.3} seconds and for decay @code{0.8}
1226 Set list of points for transfer function, specified in dB relative to maximum
1227 possible signal amplitude.
1228 Each key points list need to be defined using the following syntax:
1229 @code{x0/y0 x1/y1 x2/y2 ...}.
1231 The input values must be in strictly increasing order but the transfer
1232 function does not have to be monotonically rising.
1233 The point @code{0/0} is assumed but may be overridden (by @code{0/out-dBn}).
1234 Typical values for the transfer function are @code{-70/-70 -60/-20}.
1237 Set amount for which the points at where adjacent line segments on the
1238 transfer function meet will be rounded. Defaults is @code{0.01}.
1241 Set additional gain in dB to be applied at all points on the transfer function
1242 and allows easy adjustment of the overall gain.
1243 Default is @code{0}.
1246 Set initial volume in dB to be assumed for each channel when filtering starts.
1247 This permits the user to supply a nominal level initially, so that,
1248 for example, a very large gain is not applied to initial signal levels before
1249 the companding has begun to operate. A typical value for audio which is
1250 initially quiet is -90 dB. Default is @code{0}.
1253 Set delay in seconds. Default is @code{0}. The input audio
1254 is analysed immediately, but audio is delayed before being fed to the
1255 volume adjuster. Specifying a delay approximately equal to the attack/decay
1256 times allows the filter to effectively operate in predictive rather than
1260 @subsection Examples
1263 Make music with both quiet and loud passages suitable for listening
1264 in a noisy environment:
1266 compand=.3 .3:1 1:-90/-60 -60/-40 -40/-30 -20/-20:6:0:-90:0.2
1270 Noise-gate for when the noise is at a lower level than the signal:
1272 compand=.1 .1:.2 .2:-900/-900 -50.1/-900 -50/-50:.01:0:-90:.1
1276 Here is another noise-gate, this time for when the noise is at a higher level
1277 than the signal (making it, in some ways, similar to squelch):
1279 compand=.1 .1:.1 .1:-45.1/-45.1 -45/-900 0/-900:.01:45:-90:.1
1285 Make audio easier to listen to on headphones.
1287 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1288 so that when listened to on headphones the stereo image is moved from
1289 inside your head (standard for headphones) to outside and in front of
1290 the listener (standard for speakers).
1296 Apply a two-pole peaking equalisation (EQ) filter. With this
1297 filter, the signal-level at and around a selected frequency can
1298 be increased or decreased, whilst (unlike bandpass and bandreject
1299 filters) that at all other frequencies is unchanged.
1301 In order to produce complex equalisation curves, this filter can
1302 be given several times, each with a different central frequency.
1304 The filter accepts the following options:
1308 Set the filter's central frequency in Hz.
1311 Set method to specify band-width of filter.
1324 Specify the band-width of a filter in width_type units.
1327 Set the required gain or attenuation in dB.
1328 Beware of clipping when using a positive gain.
1333 Apply a high-pass filter with 3dB point frequency.
1334 The filter can be either single-pole, or double-pole (the default).
1335 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1337 The filter accepts the following options:
1341 Set frequency in Hz. Default is 3000.
1344 Set number of poles. Default is 2.
1347 Set method to specify band-width of filter.
1360 Specify the band-width of a filter in width_type units.
1361 Applies only to double-pole filter.
1362 The default is 0.707q and gives a Butterworth response.
1367 Join multiple input streams into one multi-channel stream.
1369 The filter accepts the following named parameters:
1373 Number of input streams. Defaults to 2.
1375 @item channel_layout
1376 Desired output channel layout. Defaults to stereo.
1379 Map channels from inputs to output. The argument is a '|'-separated list of
1380 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1381 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1382 can be either the name of the input channel (e.g. FL for front left) or its
1383 index in the specified input stream. @var{out_channel} is the name of the output
1387 The filter will attempt to guess the mappings when those are not specified
1388 explicitly. It does so by first trying to find an unused matching input channel
1389 and if that fails it picks the first unused input channel.
1391 E.g. to join 3 inputs (with properly set channel layouts)
1393 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1396 To build a 5.1 output from 6 single-channel streams:
1398 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1399 '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'
1405 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1407 To enable compilation of this filter you need to configure FFmpeg with "--enable-ladspa".
1411 Specifies the name of LADSPA plugin library to load. If the environment
1412 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1413 each one of the directories specified by the colon separated list in
1414 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1415 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1416 @file{/usr/lib/ladspa/}.
1419 Specifies the plugin within the library. Some libraries contain only
1420 one plugin, but others contain many of them. If this is not set filter
1421 will list all available plugins within the specified library.
1424 Set the '|' separated list of controls which are zero or more floating point
1425 values that determine the behavior of the loaded plugin (for example delay,
1427 Controls need to be defined using the following syntax:
1428 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1429 @var{valuei} is the value set on the @var{i}-th control.
1430 If @option{controls} is set to @code{help}, all available controls and
1431 their valid ranges are printed.
1433 @item sample_rate, s
1434 Specify the sample rate, default to 44100. Only used if plugin have
1438 Set the number of samples per channel per each output frame, default
1439 is 1024. Only used if plugin have zero inputs.
1442 Set the minimum duration of the sourced audio. See the function
1443 @code{av_parse_time()} for the accepted format, also check the "Time duration"
1444 section in the ffmpeg-utils manual.
1445 Note that the resulting duration may be greater than the specified duration,
1446 as the generated audio is always cut at the end of a complete frame.
1447 If not specified, or the expressed duration is negative, the audio is
1448 supposed to be generated forever.
1449 Only used if plugin have zero inputs.
1453 @subsection Examples
1457 List all available plugins within amp (LADSPA example plugin) library:
1463 List all available controls and their valid ranges for @code{vcf_notch}
1464 plugin from @code{VCF} library:
1466 ladspa=f=vcf:p=vcf_notch:c=help
1470 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1473 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1477 Add reverberation to the audio using TAP-plugins
1478 (Tom's Audio Processing plugins):
1480 ladspa=file=tap_reverb:tap_reverb
1484 Generate white noise, with 0.2 amplitude:
1486 ladspa=file=cmt:noise_source_white:c=c0=.2
1490 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1491 @code{C* Audio Plugin Suite} (CAPS) library:
1493 ladspa=file=caps:Click:c=c1=20'
1497 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1499 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1505 Apply a low-pass filter with 3dB point frequency.
1506 The filter can be either single-pole or double-pole (the default).
1507 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1509 The filter accepts the following options:
1513 Set frequency in Hz. Default is 500.
1516 Set number of poles. Default is 2.
1519 Set method to specify band-width of filter.
1532 Specify the band-width of a filter in width_type units.
1533 Applies only to double-pole filter.
1534 The default is 0.707q and gives a Butterworth response.
1539 Mix channels with specific gain levels. The filter accepts the output
1540 channel layout followed by a set of channels definitions.
1542 This filter is also designed to remap efficiently the channels of an audio
1545 The filter accepts parameters of the form:
1546 "@var{l}:@var{outdef}:@var{outdef}:..."
1550 output channel layout or number of channels
1553 output channel specification, of the form:
1554 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1557 output channel to define, either a channel name (FL, FR, etc.) or a channel
1558 number (c0, c1, etc.)
1561 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1564 input channel to use, see out_name for details; it is not possible to mix
1565 named and numbered input channels
1568 If the `=' in a channel specification is replaced by `<', then the gains for
1569 that specification will be renormalized so that the total is 1, thus
1570 avoiding clipping noise.
1572 @subsection Mixing examples
1574 For example, if you want to down-mix from stereo to mono, but with a bigger
1575 factor for the left channel:
1577 pan=1:c0=0.9*c0+0.1*c1
1580 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1581 7-channels surround:
1583 pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1586 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1587 that should be preferred (see "-ac" option) unless you have very specific
1590 @subsection Remapping examples
1592 The channel remapping will be effective if, and only if:
1595 @item gain coefficients are zeroes or ones,
1596 @item only one input per channel output,
1599 If all these conditions are satisfied, the filter will notify the user ("Pure
1600 channel mapping detected"), and use an optimized and lossless method to do the
1603 For example, if you have a 5.1 source and want a stereo audio stream by
1604 dropping the extra channels:
1606 pan="stereo: c0=FL : c1=FR"
1609 Given the same source, you can also switch front left and front right channels
1610 and keep the input channel layout:
1612 pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
1615 If the input is a stereo audio stream, you can mute the front left channel (and
1616 still keep the stereo channel layout) with:
1621 Still with a stereo audio stream input, you can copy the right channel in both
1622 front left and right:
1624 pan="stereo: c0=FR : c1=FR"
1629 Convert the audio sample format, sample rate and channel layout. This filter is
1630 not meant to be used directly.
1632 @section silencedetect
1634 Detect silence in an audio stream.
1636 This filter logs a message when it detects that the input audio volume is less
1637 or equal to a noise tolerance value for a duration greater or equal to the
1638 minimum detected noise duration.
1640 The printed times and duration are expressed in seconds.
1642 The filter accepts the following options:
1646 Set silence duration until notification (default is 2 seconds).
1649 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1650 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1653 @subsection Examples
1657 Detect 5 seconds of silence with -50dB noise tolerance:
1659 silencedetect=n=-50dB:d=5
1663 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1664 tolerance in @file{silence.mp3}:
1666 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1672 Boost or cut treble (upper) frequencies of the audio using a two-pole
1673 shelving filter with a response similar to that of a standard
1674 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1676 The filter accepts the following options:
1680 Give the gain at whichever is the lower of ~22 kHz and the
1681 Nyquist frequency. Its useful range is about -20 (for a large cut)
1682 to +20 (for a large boost). Beware of clipping when using a positive gain.
1685 Set the filter's central frequency and so can be used
1686 to extend or reduce the frequency range to be boosted or cut.
1687 The default value is @code{3000} Hz.
1690 Set method to specify band-width of filter.
1703 Determine how steep is the filter's shelf transition.
1708 Adjust the input audio volume.
1710 The filter accepts the following options:
1715 Expresses how the audio volume will be increased or decreased.
1717 Output values are clipped to the maximum value.
1719 The output audio volume is given by the relation:
1721 @var{output_volume} = @var{volume} * @var{input_volume}
1724 Default value for @var{volume} is 1.0.
1727 Set the mathematical precision.
1729 This determines which input sample formats will be allowed, which affects the
1730 precision of the volume scaling.
1734 8-bit fixed-point; limits input sample format to U8, S16, and S32.
1736 32-bit floating-point; limits input sample format to FLT. (default)
1738 64-bit floating-point; limits input sample format to DBL.
1742 @subsection Examples
1746 Halve the input audio volume:
1750 volume=volume=-6.0206dB
1753 In all the above example the named key for @option{volume} can be
1754 omitted, for example like in:
1760 Increase input audio power by 6 decibels using fixed-point precision:
1762 volume=volume=6dB:precision=fixed
1766 @section volumedetect
1768 Detect the volume of the input video.
1770 The filter has no parameters. The input is not modified. Statistics about
1771 the volume will be printed in the log when the input stream end is reached.
1773 In particular it will show the mean volume (root mean square), maximum
1774 volume (on a per-sample basis), and the beginning of a histogram of the
1775 registered volume values (from the maximum value to a cumulated 1/1000 of
1778 All volumes are in decibels relative to the maximum PCM value.
1780 @subsection Examples
1782 Here is an excerpt of the output:
1784 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
1785 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
1786 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
1787 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
1788 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
1789 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
1790 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
1791 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
1792 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
1798 The mean square energy is approximately -27 dB, or 10^-2.7.
1800 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
1802 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
1805 In other words, raising the volume by +4 dB does not cause any clipping,
1806 raising it by +5 dB causes clipping for 6 samples, etc.
1808 @c man end AUDIO FILTERS
1810 @chapter Audio Sources
1811 @c man begin AUDIO SOURCES
1813 Below is a description of the currently available audio sources.
1817 Buffer audio frames, and make them available to the filter chain.
1819 This source is mainly intended for a programmatic use, in particular
1820 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
1822 It accepts the following named parameters:
1827 Timebase which will be used for timestamps of submitted frames. It must be
1828 either a floating-point number or in @var{numerator}/@var{denominator} form.
1831 The sample rate of the incoming audio buffers.
1834 The sample format of the incoming audio buffers.
1835 Either a sample format name or its corresponging integer representation from
1836 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
1838 @item channel_layout
1839 The channel layout of the incoming audio buffers.
1840 Either a channel layout name from channel_layout_map in
1841 @file{libavutil/channel_layout.c} or its corresponding integer representation
1842 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
1845 The number of channels of the incoming audio buffers.
1846 If both @var{channels} and @var{channel_layout} are specified, then they
1851 @subsection Examples
1854 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
1857 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
1858 Since the sample format with name "s16p" corresponds to the number
1859 6 and the "stereo" channel layout corresponds to the value 0x3, this is
1862 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
1867 Generate an audio signal specified by an expression.
1869 This source accepts in input one or more expressions (one for each
1870 channel), which are evaluated and used to generate a corresponding
1873 This source accepts the following options:
1877 Set the '|'-separated expressions list for each separate channel. In case the
1878 @option{channel_layout} option is not specified, the selected channel layout
1879 depends on the number of provided expressions.
1881 @item channel_layout, c
1882 Set the channel layout. The number of channels in the specified layout
1883 must be equal to the number of specified expressions.
1886 Set the minimum duration of the sourced audio. See the function
1887 @code{av_parse_time()} for the accepted format.
1888 Note that the resulting duration may be greater than the specified
1889 duration, as the generated audio is always cut at the end of a
1892 If not specified, or the expressed duration is negative, the audio is
1893 supposed to be generated forever.
1896 Set the number of samples per channel per each output frame,
1899 @item sample_rate, s
1900 Specify the sample rate, default to 44100.
1903 Each expression in @var{exprs} can contain the following constants:
1907 number of the evaluated sample, starting from 0
1910 time of the evaluated sample expressed in seconds, starting from 0
1917 @subsection Examples
1927 Generate a sin signal with frequency of 440 Hz, set sample rate to
1930 aevalsrc="sin(440*2*PI*t):s=8000"
1934 Generate a two channels signal, specify the channel layout (Front
1935 Center + Back Center) explicitly:
1937 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
1941 Generate white noise:
1943 aevalsrc="-2+random(0)"
1947 Generate an amplitude modulated signal:
1949 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
1953 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
1955 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
1962 Null audio source, return unprocessed audio frames. It is mainly useful
1963 as a template and to be employed in analysis / debugging tools, or as
1964 the source for filters which ignore the input data (for example the sox
1967 This source accepts the following options:
1971 @item channel_layout, cl
1973 Specify the channel layout, and can be either an integer or a string
1974 representing a channel layout. The default value of @var{channel_layout}
1977 Check the channel_layout_map definition in
1978 @file{libavutil/channel_layout.c} for the mapping between strings and
1979 channel layout values.
1981 @item sample_rate, r
1982 Specify the sample rate, and defaults to 44100.
1985 Set the number of samples per requested frames.
1989 @subsection Examples
1993 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
1995 anullsrc=r=48000:cl=4
1999 Do the same operation with a more obvious syntax:
2001 anullsrc=r=48000:cl=mono
2005 All the parameters need to be explicitly defined.
2009 Synthesize a voice utterance using the libflite library.
2011 To enable compilation of this filter you need to configure FFmpeg with
2012 @code{--enable-libflite}.
2014 Note that the flite library is not thread-safe.
2016 The filter accepts the following options:
2021 If set to 1, list the names of the available voices and exit
2022 immediately. Default value is 0.
2025 Set the maximum number of samples per frame. Default value is 512.
2028 Set the filename containing the text to speak.
2031 Set the text to speak.
2034 Set the voice to use for the speech synthesis. Default value is
2035 @code{kal}. See also the @var{list_voices} option.
2038 @subsection Examples
2042 Read from file @file{speech.txt}, and synthetize the text using the
2043 standard flite voice:
2045 flite=textfile=speech.txt
2049 Read the specified text selecting the @code{slt} voice:
2051 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2055 Input text to ffmpeg:
2057 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2061 Make @file{ffplay} speak the specified text, using @code{flite} and
2062 the @code{lavfi} device:
2064 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2068 For more information about libflite, check:
2069 @url{http://www.speech.cs.cmu.edu/flite/}
2073 Generate an audio signal made of a sine wave with amplitude 1/8.
2075 The audio signal is bit-exact.
2077 The filter accepts the following options:
2082 Set the carrier frequency. Default is 440 Hz.
2084 @item beep_factor, b
2085 Enable a periodic beep every second with frequency @var{beep_factor} times
2086 the carrier frequency. Default is 0, meaning the beep is disabled.
2088 @item sample_rate, r
2089 Specify the sample rate, default is 44100.
2092 Specify the duration of the generated audio stream.
2094 @item samples_per_frame
2095 Set the number of samples per output frame, default is 1024.
2098 @subsection Examples
2103 Generate a simple 440 Hz sine wave:
2109 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2113 sine=frequency=220:beep_factor=4:duration=5
2118 @c man end AUDIO SOURCES
2120 @chapter Audio Sinks
2121 @c man begin AUDIO SINKS
2123 Below is a description of the currently available audio sinks.
2125 @section abuffersink
2127 Buffer audio frames, and make them available to the end of filter chain.
2129 This sink is mainly intended for programmatic use, in particular
2130 through the interface defined in @file{libavfilter/buffersink.h}
2131 or the options system.
2133 It accepts a pointer to an AVABufferSinkContext structure, which
2134 defines the incoming buffers' formats, to be passed as the opaque
2135 parameter to @code{avfilter_init_filter} for initialization.
2139 Null audio sink, do absolutely nothing with the input audio. It is
2140 mainly useful as a template and to be employed in analysis / debugging
2143 @c man end AUDIO SINKS
2145 @chapter Video Filters
2146 @c man begin VIDEO FILTERS
2148 When you configure your FFmpeg build, you can disable any of the
2149 existing filters using @code{--disable-filters}.
2150 The configure output will show the video filters included in your
2153 Below is a description of the currently available video filters.
2155 @section alphaextract
2157 Extract the alpha component from the input as a grayscale video. This
2158 is especially useful with the @var{alphamerge} filter.
2162 Add or replace the alpha component of the primary input with the
2163 grayscale value of a second input. This is intended for use with
2164 @var{alphaextract} to allow the transmission or storage of frame
2165 sequences that have alpha in a format that doesn't support an alpha
2168 For example, to reconstruct full frames from a normal YUV-encoded video
2169 and a separate video created with @var{alphaextract}, you might use:
2171 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2174 Since this filter is designed for reconstruction, it operates on frame
2175 sequences without considering timestamps, and terminates when either
2176 input reaches end of stream. This will cause problems if your encoding
2177 pipeline drops frames. If you're trying to apply an image as an
2178 overlay to a video stream, consider the @var{overlay} filter instead.
2182 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2183 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2184 Substation Alpha) subtitles files.
2188 Compute the bounding box for the non-black pixels in the input frame
2191 This filter computes the bounding box containing all the pixels with a
2192 luminance value greater than the minimum allowed value.
2193 The parameters describing the bounding box are printed on the filter
2196 The filter accepts the following option:
2200 Set the minimal luminance value. Default is @code{16}.
2203 @section blackdetect
2205 Detect video intervals that are (almost) completely black. Can be
2206 useful to detect chapter transitions, commercials, or invalid
2207 recordings. Output lines contains the time for the start, end and
2208 duration of the detected black interval expressed in seconds.
2210 In order to display the output lines, you need to set the loglevel at
2211 least to the AV_LOG_INFO value.
2213 The filter accepts the following options:
2216 @item black_min_duration, d
2217 Set the minimum detected black duration expressed in seconds. It must
2218 be a non-negative floating point number.
2220 Default value is 2.0.
2222 @item picture_black_ratio_th, pic_th
2223 Set the threshold for considering a picture "black".
2224 Express the minimum value for the ratio:
2226 @var{nb_black_pixels} / @var{nb_pixels}
2229 for which a picture is considered black.
2230 Default value is 0.98.
2232 @item pixel_black_th, pix_th
2233 Set the threshold for considering a pixel "black".
2235 The threshold expresses the maximum pixel luminance value for which a
2236 pixel is considered "black". The provided value is scaled according to
2237 the following equation:
2239 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2242 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2243 the input video format, the range is [0-255] for YUV full-range
2244 formats and [16-235] for YUV non full-range formats.
2246 Default value is 0.10.
2249 The following example sets the maximum pixel threshold to the minimum
2250 value, and detects only black intervals of 2 or more seconds:
2252 blackdetect=d=2:pix_th=0.00
2257 Detect frames that are (almost) completely black. Can be useful to
2258 detect chapter transitions or commercials. Output lines consist of
2259 the frame number of the detected frame, the percentage of blackness,
2260 the position in the file if known or -1 and the timestamp in seconds.
2262 In order to display the output lines, you need to set the loglevel at
2263 least to the AV_LOG_INFO value.
2265 The filter accepts the following options:
2270 Set the percentage of the pixels that have to be below the threshold, defaults
2273 @item threshold, thresh
2274 Set the threshold below which a pixel value is considered black, defaults to
2281 Blend two video frames into each other.
2283 It takes two input streams and outputs one stream, the first input is the
2284 "top" layer and second input is "bottom" layer.
2285 Output terminates when shortest input terminates.
2287 A description of the accepted options follows.
2295 Set blend mode for specific pixel component or all pixel components in case
2296 of @var{all_mode}. Default value is @code{normal}.
2298 Available values for component modes are:
2331 Set blend opacity for specific pixel component or all pixel components in case
2332 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2339 Set blend expression for specific pixel component or all pixel components in case
2340 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2342 The expressions can use the following variables:
2346 The sequential number of the filtered frame, starting from @code{0}.
2350 the coordinates of the current sample
2354 the width and height of currently filtered plane
2358 Width and height scale depending on the currently filtered plane. It is the
2359 ratio between the corresponding luma plane number of pixels and the current
2360 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2361 @code{0.5,0.5} for chroma planes.
2364 Time of the current frame, expressed in seconds.
2367 Value of pixel component at current location for first video frame (top layer).
2370 Value of pixel component at current location for second video frame (bottom layer).
2374 Force termination when the shortest input terminates. Default is @code{0}.
2376 Continue applying the last bottom frame after the end of the stream. A value of
2377 @code{0} disable the filter after the last frame of the bottom layer is reached.
2378 Default is @code{1}.
2381 @subsection Examples
2385 Apply transition from bottom layer to top layer in first 10 seconds:
2387 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2391 Apply 1x1 checkerboard effect:
2393 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2399 Apply boxblur algorithm to the input video.
2401 The filter accepts the following options:
2405 @item luma_radius, lr
2406 @item luma_power, lp
2407 @item chroma_radius, cr
2408 @item chroma_power, cp
2409 @item alpha_radius, ar
2410 @item alpha_power, ap
2414 A description of the accepted options follows.
2417 @item luma_radius, lr
2418 @item chroma_radius, cr
2419 @item alpha_radius, ar
2420 Set an expression for the box radius in pixels used for blurring the
2421 corresponding input plane.
2423 The radius value must be a non-negative number, and must not be
2424 greater than the value of the expression @code{min(w,h)/2} for the
2425 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2428 Default value for @option{luma_radius} is "2". If not specified,
2429 @option{chroma_radius} and @option{alpha_radius} default to the
2430 corresponding value set for @option{luma_radius}.
2432 The expressions can contain the following constants:
2436 the input width and height in pixels
2440 the input chroma image width and height in pixels
2444 horizontal and vertical chroma subsample values. For example for the
2445 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2448 @item luma_power, lp
2449 @item chroma_power, cp
2450 @item alpha_power, ap
2451 Specify how many times the boxblur filter is applied to the
2452 corresponding plane.
2454 Default value for @option{luma_power} is 2. If not specified,
2455 @option{chroma_power} and @option{alpha_power} default to the
2456 corresponding value set for @option{luma_power}.
2458 A value of 0 will disable the effect.
2461 @subsection Examples
2465 Apply a boxblur filter with luma, chroma, and alpha radius
2468 boxblur=luma_radius=2:luma_power=1
2473 Set luma radius to 2, alpha and chroma radius to 0:
2475 boxblur=2:1:cr=0:ar=0
2479 Set luma and chroma radius to a fraction of the video dimension:
2481 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2485 @section colorbalance
2486 Modify intensity of primary colors (red, green and blue) of input frames.
2488 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2489 regions for the red-cyan, green-magenta or blue-yellow balance.
2491 A positive adjustment value shifts the balance towards the primary color, a negative
2492 value towards the complementary color.
2494 The filter accepts the following options:
2500 Adjust red, green and blue shadows (darkest pixels).
2505 Adjust red, green and blue midtones (medium pixels).
2510 Adjust red, green and blue highlights (brightest pixels).
2512 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2515 @subsection Examples
2519 Add red color cast to shadows:
2525 @section colorchannelmixer
2527 Adjust video input frames by re-mixing color channels.
2529 This filter modifies a color channel by adding the values associated to
2530 the other channels of the same pixels. For example if the value to
2531 modify is red, the output value will be:
2533 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2536 The filter accepts the following options:
2543 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2544 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2550 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2551 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2557 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2558 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2564 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2565 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2567 Allowed ranges for options are @code{[-2.0, 2.0]}.
2570 @subsection Examples
2574 Convert source to grayscale:
2576 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2579 Simulate sepia tones:
2581 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
2585 @section colormatrix
2587 Convert color matrix.
2589 The filter accepts the following options:
2594 Specify the source and destination color matrix. Both values must be
2597 The accepted values are:
2613 For example to convert from BT.601 to SMPTE-240M, use the command:
2615 colormatrix=bt601:smpte240m
2620 Copy the input source unchanged to the output. Mainly useful for
2625 Crop the input video to given dimensions.
2627 The filter accepts the following options:
2631 Width of the output video. It defaults to @code{iw}.
2632 This expression is evaluated only once during the filter
2636 Height of the output video. It defaults to @code{ih}.
2637 This expression is evaluated only once during the filter
2641 Horizontal position, in the input video, of the left edge of the output video.
2642 It defaults to @code{(in_w-out_w)/2}.
2643 This expression is evaluated per-frame.
2646 Vertical position, in the input video, of the top edge of the output video.
2647 It defaults to @code{(in_h-out_h)/2}.
2648 This expression is evaluated per-frame.
2651 If set to 1 will force the output display aspect ratio
2652 to be the same of the input, by changing the output sample aspect
2653 ratio. It defaults to 0.
2656 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
2657 expressions containing the following constants:
2662 the computed values for @var{x} and @var{y}. They are evaluated for
2667 the input width and height
2671 same as @var{in_w} and @var{in_h}
2675 the output (cropped) width and height
2679 same as @var{out_w} and @var{out_h}
2682 same as @var{iw} / @var{ih}
2685 input sample aspect ratio
2688 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
2692 horizontal and vertical chroma subsample values. For example for the
2693 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2696 the number of input frame, starting from 0
2699 the position in the file of the input frame, NAN if unknown
2702 timestamp expressed in seconds, NAN if the input timestamp is unknown
2706 The expression for @var{out_w} may depend on the value of @var{out_h},
2707 and the expression for @var{out_h} may depend on @var{out_w}, but they
2708 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
2709 evaluated after @var{out_w} and @var{out_h}.
2711 The @var{x} and @var{y} parameters specify the expressions for the
2712 position of the top-left corner of the output (non-cropped) area. They
2713 are evaluated for each frame. If the evaluated value is not valid, it
2714 is approximated to the nearest valid value.
2716 The expression for @var{x} may depend on @var{y}, and the expression
2717 for @var{y} may depend on @var{x}.
2719 @subsection Examples
2723 Crop area with size 100x100 at position (12,34).
2728 Using named options, the example above becomes:
2730 crop=w=100:h=100:x=12:y=34
2734 Crop the central input area with size 100x100:
2740 Crop the central input area with size 2/3 of the input video:
2742 crop=2/3*in_w:2/3*in_h
2746 Crop the input video central square:
2753 Delimit the rectangle with the top-left corner placed at position
2754 100:100 and the right-bottom corner corresponding to the right-bottom
2755 corner of the input image:
2757 crop=in_w-100:in_h-100:100:100
2761 Crop 10 pixels from the left and right borders, and 20 pixels from
2762 the top and bottom borders
2764 crop=in_w-2*10:in_h-2*20
2768 Keep only the bottom right quarter of the input image:
2770 crop=in_w/2:in_h/2:in_w/2:in_h/2
2774 Crop height for getting Greek harmony:
2776 crop=in_w:1/PHI*in_w
2780 Appply trembling effect:
2782 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)
2786 Apply erratic camera effect depending on timestamp:
2788 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)"
2792 Set x depending on the value of y:
2794 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
2800 Auto-detect crop size.
2802 Calculate necessary cropping parameters and prints the recommended
2803 parameters through the logging system. The detected dimensions
2804 correspond to the non-black area of the input video.
2806 The filter accepts the following options:
2811 Set higher black value threshold, which can be optionally specified
2812 from nothing (0) to everything (255). An intensity value greater
2813 to the set value is considered non-black. Default value is 24.
2816 Set the value for which the width/height should be divisible by. The
2817 offset is automatically adjusted to center the video. Use 2 to get
2818 only even dimensions (needed for 4:2:2 video). 16 is best when
2819 encoding to most video codecs. Default value is 16.
2821 @item reset_count, reset
2822 Set the counter that determines after how many frames cropdetect will
2823 reset the previously detected largest video area and start over to
2824 detect the current optimal crop area. Default value is 0.
2826 This can be useful when channel logos distort the video area. 0
2827 indicates never reset and return the largest area encountered during
2834 Apply color adjustments using curves.
2836 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
2837 component (red, green and blue) has its values defined by @var{N} key points
2838 tied from each other using a smooth curve. The x-axis represents the pixel
2839 values from the input frame, and the y-axis the new pixel values to be set for
2842 By default, a component curve is defined by the two points @var{(0;0)} and
2843 @var{(1;1)}. This creates a straight line where each original pixel value is
2844 "adjusted" to its own value, which means no change to the image.
2846 The filter allows you to redefine these two points and add some more. A new
2847 curve (using a natural cubic spline interpolation) will be define to pass
2848 smoothly through all these new coordinates. The new defined points needs to be
2849 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
2850 be in the @var{[0;1]} interval. If the computed curves happened to go outside
2851 the vector spaces, the values will be clipped accordingly.
2853 If there is no key point defined in @code{x=0}, the filter will automatically
2854 insert a @var{(0;0)} point. In the same way, if there is no key point defined
2855 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
2857 The filter accepts the following options:
2861 Select one of the available color presets. This option can be used in addition
2862 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
2863 options takes priority on the preset values.
2864 Available presets are:
2867 @item color_negative
2870 @item increase_contrast
2872 @item linear_contrast
2873 @item medium_contrast
2875 @item strong_contrast
2878 Default is @code{none}.
2880 Set the master key points. These points will define a second pass mapping. It
2881 is sometimes called a "luminance" or "value" mapping. It can be used with
2882 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
2883 post-processing LUT.
2885 Set the key points for the red component.
2887 Set the key points for the green component.
2889 Set the key points for the blue component.
2891 Set the key points for all components (not including master).
2892 Can be used in addition to the other key points component
2893 options. In this case, the unset component(s) will fallback on this
2894 @option{all} setting.
2896 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
2899 To avoid some filtergraph syntax conflicts, each key points list need to be
2900 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
2902 @subsection Examples
2906 Increase slightly the middle level of blue:
2908 curves=blue='0.5/0.58'
2914 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
2916 Here we obtain the following coordinates for each components:
2919 @code{(0;0.11) (0.42;0.51) (1;0.95)}
2921 @code{(0;0) (0.50;0.48) (1;1)}
2923 @code{(0;0.22) (0.49;0.44) (1;0.80)}
2927 The previous example can also be achieved with the associated built-in preset:
2929 curves=preset=vintage
2939 Use a Photoshop preset and redefine the points of the green component:
2941 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
2947 Denoise frames using 2D DCT (frequency domain filtering).
2949 This filter is not designed for real time and can be extremely slow.
2951 The filter accepts the following options:
2955 Set the noise sigma constant.
2957 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
2958 coefficient (absolute value) below this threshold with be dropped.
2960 If you need a more advanced filtering, see @option{expr}.
2962 Default is @code{0}.
2965 Set number overlapping pixels for each block. Each block is of size
2966 @code{16x16}. Since the filter can be slow, you may want to reduce this value,
2967 at the cost of a less effective filter and the risk of various artefacts.
2969 If the overlapping value doesn't allow to process the whole input width or
2970 height, a warning will be displayed and according borders won't be denoised.
2972 Default value is @code{15}.
2975 Set the coefficient factor expression.
2977 For each coefficient of a DCT block, this expression will be evaluated as a
2978 multiplier value for the coefficient.
2980 If this is option is set, the @option{sigma} option will be ignored.
2982 The absolute value of the coefficient can be accessed through the @var{c}
2986 @subsection Examples
2988 Apply a denoise with a @option{sigma} of @code{4.5}:
2993 The same operation can be achieved using the expression system:
2995 dctdnoiz=e='gte(c, 4.5*3)'
3001 Drop duplicated frames at regular intervals.
3003 The filter accepts the following options:
3007 Set the number of frames from which one will be dropped. Setting this to
3008 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3009 Default is @code{5}.
3012 Set the threshold for duplicate detection. If the difference metric for a frame
3013 is less than or equal to this value, then it is declared as duplicate. Default
3017 Set scene change threshold. Default is @code{15}.
3021 Set the size of the x and y-axis blocks used during metric calculations.
3022 Larger blocks give better noise suppression, but also give worse detection of
3023 small movements. Must be a power of two. Default is @code{32}.
3026 Mark main input as a pre-processed input and activate clean source input
3027 stream. This allows the input to be pre-processed with various filters to help
3028 the metrics calculation while keeping the frame selection lossless. When set to
3029 @code{1}, the first stream is for the pre-processed input, and the second
3030 stream is the clean source from where the kept frames are chosen. Default is
3034 Set whether or not chroma is considered in the metric calculations. Default is
3040 Suppress a TV station logo by a simple interpolation of the surrounding
3041 pixels. Just set a rectangle covering the logo and watch it disappear
3042 (and sometimes something even uglier appear - your mileage may vary).
3044 This filter accepts the following options:
3049 Specify the top left corner coordinates of the logo. They must be
3054 Specify the width and height of the logo to clear. They must be
3058 Specify the thickness of the fuzzy edge of the rectangle (added to
3059 @var{w} and @var{h}). The default value is 4.
3062 When set to 1, a green rectangle is drawn on the screen to simplify
3063 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3064 The default value is 0.
3066 The rectangle is drawn on the outermost pixels which will be (partly)
3067 replaced with interpolated values. The values of the next pixels
3068 immediately outside this rectangle in each direction will be used to
3069 compute the interpolated pixel values inside the rectangle.
3073 @subsection Examples
3077 Set a rectangle covering the area with top left corner coordinates 0,0
3078 and size 100x77, setting a band of size 10:
3080 delogo=x=0:y=0:w=100:h=77:band=10
3087 Attempt to fix small changes in horizontal and/or vertical shift. This
3088 filter helps remove camera shake from hand-holding a camera, bumping a
3089 tripod, moving on a vehicle, etc.
3091 The filter accepts the following options:
3099 Specify a rectangular area where to limit the search for motion
3101 If desired the search for motion vectors can be limited to a
3102 rectangular area of the frame defined by its top left corner, width
3103 and height. These parameters have the same meaning as the drawbox
3104 filter which can be used to visualise the position of the bounding
3107 This is useful when simultaneous movement of subjects within the frame
3108 might be confused for camera motion by the motion vector search.
3110 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3111 then the full frame is used. This allows later options to be set
3112 without specifying the bounding box for the motion vector search.
3114 Default - search the whole frame.
3118 Specify the maximum extent of movement in x and y directions in the
3119 range 0-64 pixels. Default 16.
3122 Specify how to generate pixels to fill blanks at the edge of the
3123 frame. Available values are:
3126 Fill zeroes at blank locations
3128 Original image at blank locations
3130 Extruded edge value at blank locations
3132 Mirrored edge at blank locations
3134 Default value is @samp{mirror}.
3137 Specify the blocksize to use for motion search. Range 4-128 pixels,
3141 Specify the contrast threshold for blocks. Only blocks with more than
3142 the specified contrast (difference between darkest and lightest
3143 pixels) will be considered. Range 1-255, default 125.
3146 Specify the search strategy. Available values are:
3149 Set exhaustive search
3151 Set less exhaustive search.
3153 Default value is @samp{exhaustive}.
3156 If set then a detailed log of the motion search is written to the
3160 If set to 1, specify using OpenCL capabilities, only available if
3161 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3167 Draw a colored box on the input image.
3169 This filter accepts the following options:
3174 The expressions which specify the top left corner coordinates of the box. Default to 0.
3178 The expressions which specify the width and height of the box, if 0 they are interpreted as
3179 the input width and height. Default to 0.
3182 Specify the color of the box to write, it can be the name of a color
3183 (case insensitive match) or a 0xRRGGBB[AA] sequence. If the special
3184 value @code{invert} is used, the box edge color is the same as the
3185 video with inverted luma.
3188 The expression which sets the thickness of the box edge. Default value is @code{3}.
3190 See below for the list of accepted constants.
3193 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3194 following constants:
3198 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3202 horizontal and vertical chroma subsample values. For example for the
3203 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3207 The input width and height.
3210 The input sample aspect ratio.
3214 The x and y offset coordinates where the box is drawn.
3218 The width and height of the drawn box.
3221 The thickness of the drawn box.
3223 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3224 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3228 @subsection Examples
3232 Draw a black box around the edge of the input image:
3238 Draw a box with color red and an opacity of 50%:
3240 drawbox=10:20:200:60:red@@0.5
3243 The previous example can be specified as:
3245 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3249 Fill the box with pink color:
3251 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3255 Draw a 2-pixel red 2.40:1 mask:
3257 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
3263 Draw a grid on the input image.
3265 This filter accepts the following options:
3270 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3274 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3275 input width and height, respectively, minus @code{thickness}, so image gets
3276 framed. Default to 0.
3279 Specify the color of the grid, it can be the name of a color
3280 (case insensitive match) or a 0xRRGGBB[AA] sequence. If the special
3281 value @code{invert} is used, the grid color is the same as the
3282 video with inverted luma.
3283 Note that you can append opacity value (in range of 0.0 - 1.0)
3284 to color name after @@ sign.
3287 The expression which sets the thickness of the grid line. Default value is @code{1}.
3289 See below for the list of accepted constants.
3292 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3293 following constants:
3297 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3301 horizontal and vertical chroma subsample values. For example for the
3302 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3306 The input grid cell width and height.
3309 The input sample aspect ratio.
3313 The x and y coordinates of some point of grid intersection (meant to configure offset).
3317 The width and height of the drawn cell.
3320 The thickness of the drawn cell.
3322 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3323 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3327 @subsection Examples
3331 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3333 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3337 Draw a white 3x3 grid with an opacity of 50%:
3339 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3346 Draw text string or text from specified file on top of video using the
3347 libfreetype library.
3349 To enable compilation of this filter you need to configure FFmpeg with
3350 @code{--enable-libfreetype}.
3354 The description of the accepted parameters follows.
3359 Used to draw a box around text using background color.
3360 Value should be either 1 (enable) or 0 (disable).
3361 The default value of @var{box} is 0.
3364 The color to be used for drawing box around text.
3365 Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
3366 (e.g. "0xff00ff"), possibly followed by an alpha specifier.
3367 The default value of @var{boxcolor} is "white".
3370 Select how the @var{text} is expanded. Can be either @code{none},
3371 @code{strftime} (deprecated) or
3372 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3376 If true, check and fix text coords to avoid clipping.
3379 The color to be used for drawing fonts.
3380 Either a string (e.g. "red") or in 0xRRGGBB[AA] format
3381 (e.g. "0xff000033"), possibly followed by an alpha specifier.
3382 The default value of @var{fontcolor} is "black".
3385 The font file to be used for drawing text. Path must be included.
3386 This parameter is mandatory.
3389 The font size to be used for drawing text.
3390 The default value of @var{fontsize} is 16.
3393 Flags to be used for loading the fonts.
3395 The flags map the corresponding flags supported by libfreetype, and are
3396 a combination of the following values:
3403 @item vertical_layout
3404 @item force_autohint
3407 @item ignore_global_advance_width
3409 @item ignore_transform
3415 Default value is "render".
3417 For more information consult the documentation for the FT_LOAD_*
3421 The color to be used for drawing a shadow behind the drawn text. It
3422 can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
3423 form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
3424 The default value of @var{shadowcolor} is "black".
3428 The x and y offsets for the text shadow position with respect to the
3429 position of the text. They can be either positive or negative
3430 values. Default value for both is "0".
3433 The starting frame number for the n/frame_num variable. The default value
3437 The size in number of spaces to use for rendering the tab.
3441 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3442 format. It can be used with or without text parameter. @var{timecode_rate}
3443 option must be specified.
3445 @item timecode_rate, rate, r
3446 Set the timecode frame rate (timecode only).
3449 The text string to be drawn. The text must be a sequence of UTF-8
3451 This parameter is mandatory if no file is specified with the parameter
3455 A text file containing text to be drawn. The text must be a sequence
3456 of UTF-8 encoded characters.
3458 This parameter is mandatory if no text string is specified with the
3459 parameter @var{text}.
3461 If both @var{text} and @var{textfile} are specified, an error is thrown.
3464 If set to 1, the @var{textfile} will be reloaded before each frame.
3465 Be sure to update it atomically, or it may be read partially, or even fail.
3469 The expressions which specify the offsets where text will be drawn
3470 within the video frame. They are relative to the top/left border of the
3473 The default value of @var{x} and @var{y} is "0".
3475 See below for the list of accepted constants and functions.
3478 The parameters for @var{x} and @var{y} are expressions containing the
3479 following constants and functions:
3483 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3487 horizontal and vertical chroma subsample values. For example for the
3488 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3491 the height of each text line
3499 @item max_glyph_a, ascent
3500 the maximum distance from the baseline to the highest/upper grid
3501 coordinate used to place a glyph outline point, for all the rendered
3503 It is a positive value, due to the grid's orientation with the Y axis
3506 @item max_glyph_d, descent
3507 the maximum distance from the baseline to the lowest grid coordinate
3508 used to place a glyph outline point, for all the rendered glyphs.
3509 This is a negative value, due to the grid's orientation, with the Y axis
3513 maximum glyph height, that is the maximum height for all the glyphs
3514 contained in the rendered text, it is equivalent to @var{ascent} -
3518 maximum glyph width, that is the maximum width for all the glyphs
3519 contained in the rendered text
3522 the number of input frame, starting from 0
3524 @item rand(min, max)
3525 return a random number included between @var{min} and @var{max}
3528 input sample aspect ratio
3531 timestamp expressed in seconds, NAN if the input timestamp is unknown
3534 the height of the rendered text
3537 the width of the rendered text
3541 the x and y offset coordinates where the text is drawn.
3543 These parameters allow the @var{x} and @var{y} expressions to refer
3544 each other, so you can for example specify @code{y=x/dar}.
3547 If libavfilter was built with @code{--enable-fontconfig}, then
3548 @option{fontfile} can be a fontconfig pattern or omitted.
3550 @anchor{drawtext_expansion}
3551 @subsection Text expansion
3553 If @option{expansion} is set to @code{strftime},
3554 the filter recognizes strftime() sequences in the provided text and
3555 expands them accordingly. Check the documentation of strftime(). This
3556 feature is deprecated.
3558 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3560 If @option{expansion} is set to @code{normal} (which is the default),
3561 the following expansion mechanism is used.
3563 The backslash character '\', followed by any character, always expands to
3564 the second character.
3566 Sequence of the form @code{%@{...@}} are expanded. The text between the
3567 braces is a function name, possibly followed by arguments separated by ':'.
3568 If the arguments contain special characters or delimiters (':' or '@}'),
3569 they should be escaped.
3571 Note that they probably must also be escaped as the value for the
3572 @option{text} option in the filter argument string and as the filter
3573 argument in the filtergraph description, and possibly also for the shell,
3574 that makes up to four levels of escaping; using a text file avoids these
3577 The following functions are available:
3582 The expression evaluation result.
3584 It must take one argument specifying the expression to be evaluated,
3585 which accepts the same constants and functions as the @var{x} and
3586 @var{y} values. Note that not all constants should be used, for
3587 example the text size is not known when evaluating the expression, so
3588 the constants @var{text_w} and @var{text_h} will have an undefined
3592 The time at which the filter is running, expressed in UTC.
3593 It can accept an argument: a strftime() format string.
3596 The time at which the filter is running, expressed in the local time zone.
3597 It can accept an argument: a strftime() format string.
3600 Frame metadata. It must take one argument specifying metadata key.
3603 The frame number, starting from 0.
3606 A 1 character description of the current picture type.
3609 The timestamp of the current frame, in seconds, with microsecond accuracy.
3613 @subsection Examples
3617 Draw "Test Text" with font FreeSerif, using the default values for the
3618 optional parameters.
3621 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
3625 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
3626 and y=50 (counting from the top-left corner of the screen), text is
3627 yellow with a red box around it. Both the text and the box have an
3631 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
3632 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
3635 Note that the double quotes are not necessary if spaces are not used
3636 within the parameter list.
3639 Show the text at the center of the video frame:
3641 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
3645 Show a text line sliding from right to left in the last row of the video
3646 frame. The file @file{LONG_LINE} is assumed to contain a single line
3649 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
3653 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
3655 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
3659 Draw a single green letter "g", at the center of the input video.
3660 The glyph baseline is placed at half screen height.
3662 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
3666 Show text for 1 second every 3 seconds:
3668 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
3672 Use fontconfig to set the font. Note that the colons need to be escaped.
3674 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
3678 Print the date of a real-time encoding (see strftime(3)):
3680 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
3685 For more information about libfreetype, check:
3686 @url{http://www.freetype.org/}.
3688 For more information about fontconfig, check:
3689 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
3693 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
3695 The filter accepts the following options:
3700 Set low and high threshold values used by the Canny thresholding
3703 The high threshold selects the "strong" edge pixels, which are then
3704 connected through 8-connectivity with the "weak" edge pixels selected
3705 by the low threshold.
3707 @var{low} and @var{high} threshold values must be choosen in the range
3708 [0,1], and @var{low} should be lesser or equal to @var{high}.
3710 Default value for @var{low} is @code{20/255}, and default value for @var{high}
3716 edgedetect=low=0.1:high=0.4
3719 @section extractplanes
3721 Extract color channel components from input video stream into
3722 separate grayscale video streams.
3724 The filter accepts the following option:
3728 Set plane(s) to extract.
3730 Available values for planes are:
3741 Choosing planes not available in the input will result in an error.
3742 That means you cannot select @code{r}, @code{g}, @code{b} planes
3743 with @code{y}, @code{u}, @code{v} planes at same time.
3746 @subsection Examples
3750 Extract luma, u and v color channel component from input video frame
3751 into 3 grayscale outputs:
3753 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
3759 Apply fade-in/out effect to input video.
3761 This filter accepts the following options:
3765 The effect type -- can be either "in" for fade-in, or "out" for a fade-out
3767 Default is @code{in}.
3769 @item start_frame, s
3770 Specify the number of the start frame for starting to apply the fade
3771 effect. Default is 0.
3774 The number of frames for which the fade effect has to last. At the end of the
3775 fade-in effect the output video will have the same intensity as the input video,
3776 at the end of the fade-out transition the output video will be completely black.
3780 If set to 1, fade only alpha channel, if one exists on the input.
3783 @item start_time, st
3784 Specify the timestamp (in seconds) of the frame to start to apply the fade
3785 effect. If both start_frame and start_time are specified, the fade will start at
3786 whichever comes last. Default is 0.
3789 The number of seconds for which the fade effect has to last. At the end of the
3790 fade-in effect the output video will have the same intensity as the input video,
3791 at the end of the fade-out transition the output video will be completely black.
3792 If both duration and nb_frames are specified, duration is used. Default is 0.
3795 @subsection Examples
3799 Fade in first 30 frames of video:
3804 The command above is equivalent to:
3810 Fade out last 45 frames of a 200-frame video:
3813 fade=type=out:start_frame=155:nb_frames=45
3817 Fade in first 25 frames and fade out last 25 frames of a 1000-frame video:
3819 fade=in:0:25, fade=out:975:25
3823 Make first 5 frames black, then fade in from frame 5-24:
3829 Fade in alpha over first 25 frames of video:
3831 fade=in:0:25:alpha=1
3835 Make first 5.5 seconds black, then fade in for 0.5 seconds:
3837 fade=t=in:st=5.5:d=0.5
3844 Extract a single field from an interlaced image using stride
3845 arithmetic to avoid wasting CPU time. The output frames are marked as
3848 The filter accepts the following options:
3852 Specify whether to extract the top (if the value is @code{0} or
3853 @code{top}) or the bottom field (if the value is @code{1} or
3859 Field matching filter for inverse telecine. It is meant to reconstruct the
3860 progressive frames from a telecined stream. The filter does not drop duplicated
3861 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
3862 followed by a decimation filter such as @ref{decimate} in the filtergraph.
3864 The separation of the field matching and the decimation is notably motivated by
3865 the possibility of inserting a de-interlacing filter fallback between the two.
3866 If the source has mixed telecined and real interlaced content,
3867 @code{fieldmatch} will not be able to match fields for the interlaced parts.
3868 But these remaining combed frames will be marked as interlaced, and thus can be
3869 de-interlaced by a later filter such as @ref{yadif} before decimation.
3871 In addition to the various configuration options, @code{fieldmatch} can take an
3872 optional second stream, activated through the @option{ppsrc} option. If
3873 enabled, the frames reconstruction will be based on the fields and frames from
3874 this second stream. This allows the first input to be pre-processed in order to
3875 help the various algorithms of the filter, while keeping the output lossless
3876 (assuming the fields are matched properly). Typically, a field-aware denoiser,
3877 or brightness/contrast adjustments can help.
3879 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
3880 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
3881 which @code{fieldmatch} is based on. While the semantic and usage are very
3882 close, some behaviour and options names can differ.
3884 The filter accepts the following options:
3888 Specify the assumed field order of the input stream. Available values are:
3892 Auto detect parity (use FFmpeg's internal parity value).
3894 Assume bottom field first.
3896 Assume top field first.
3899 Note that it is sometimes recommended not to trust the parity announced by the
3902 Default value is @var{auto}.
3905 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
3906 sense that it won't risk creating jerkiness due to duplicate frames when
3907 possible, but if there are bad edits or blended fields it will end up
3908 outputting combed frames when a good match might actually exist. On the other
3909 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
3910 but will almost always find a good frame if there is one. The other values are
3911 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
3912 jerkiness and creating duplicate frames versus finding good matches in sections
3913 with bad edits, orphaned fields, blended fields, etc.
3915 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
3917 Available values are:
3921 2-way matching (p/c)
3923 2-way matching, and trying 3rd match if still combed (p/c + n)
3925 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
3927 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
3928 still combed (p/c + n + u/b)
3930 3-way matching (p/c/n)
3932 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
3933 detected as combed (p/c/n + u/b)
3936 The parenthesis at the end indicate the matches that would be used for that
3937 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
3940 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
3943 Default value is @var{pc_n}.
3946 Mark the main input stream as a pre-processed input, and enable the secondary
3947 input stream as the clean source to pick the fields from. See the filter
3948 introduction for more details. It is similar to the @option{clip2} feature from
3951 Default value is @code{0} (disabled).
3954 Set the field to match from. It is recommended to set this to the same value as
3955 @option{order} unless you experience matching failures with that setting. In
3956 certain circumstances changing the field that is used to match from can have a
3957 large impact on matching performance. Available values are:
3961 Automatic (same value as @option{order}).
3963 Match from the bottom field.
3965 Match from the top field.
3968 Default value is @var{auto}.
3971 Set whether or not chroma is included during the match comparisons. In most
3972 cases it is recommended to leave this enabled. You should set this to @code{0}
3973 only if your clip has bad chroma problems such as heavy rainbowing or other
3974 artifacts. Setting this to @code{0} could also be used to speed things up at
3975 the cost of some accuracy.
3977 Default value is @code{1}.
3981 These define an exclusion band which excludes the lines between @option{y0} and
3982 @option{y1} from being included in the field matching decision. An exclusion
3983 band can be used to ignore subtitles, a logo, or other things that may
3984 interfere with the matching. @option{y0} sets the starting scan line and
3985 @option{y1} sets the ending line; all lines in between @option{y0} and
3986 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
3987 @option{y0} and @option{y1} to the same value will disable the feature.
3988 @option{y0} and @option{y1} defaults to @code{0}.
3991 Set the scene change detection threshold as a percentage of maximum change on
3992 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
3993 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
3994 @option{scthresh} is @code{[0.0, 100.0]}.
3996 Default value is @code{12.0}.
3999 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4000 account the combed scores of matches when deciding what match to use as the
4001 final match. Available values are:
4005 No final matching based on combed scores.
4007 Combed scores are only used when a scene change is detected.
4009 Use combed scores all the time.
4012 Default is @var{sc}.
4015 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4016 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4017 Available values are:
4021 No forced calculation.
4023 Force p/c/n calculations.
4025 Force p/c/n/u/b calculations.
4028 Default value is @var{none}.
4031 This is the area combing threshold used for combed frame detection. This
4032 essentially controls how "strong" or "visible" combing must be to be detected.
4033 Larger values mean combing must be more visible and smaller values mean combing
4034 can be less visible or strong and still be detected. Valid settings are from
4035 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4036 be detected as combed). This is basically a pixel difference value. A good
4037 range is @code{[8, 12]}.
4039 Default value is @code{9}.
4042 Sets whether or not chroma is considered in the combed frame decision. Only
4043 disable this if your source has chroma problems (rainbowing, etc.) that are
4044 causing problems for the combed frame detection with chroma enabled. Actually,
4045 using @option{chroma}=@var{0} is usually more reliable, except for the case
4046 where there is chroma only combing in the source.
4048 Default value is @code{0}.
4052 Respectively set the x-axis and y-axis size of the window used during combed
4053 frame detection. This has to do with the size of the area in which
4054 @option{combpel} pixels are required to be detected as combed for a frame to be
4055 declared combed. See the @option{combpel} parameter description for more info.
4056 Possible values are any number that is a power of 2 starting at 4 and going up
4059 Default value is @code{16}.
4062 The number of combed pixels inside any of the @option{blocky} by
4063 @option{blockx} size blocks on the frame for the frame to be detected as
4064 combed. While @option{cthresh} controls how "visible" the combing must be, this
4065 setting controls "how much" combing there must be in any localized area (a
4066 window defined by the @option{blockx} and @option{blocky} settings) on the
4067 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4068 which point no frames will ever be detected as combed). This setting is known
4069 as @option{MI} in TFM/VFM vocabulary.
4071 Default value is @code{80}.
4074 @anchor{p/c/n/u/b meaning}
4075 @subsection p/c/n/u/b meaning
4077 @subsubsection p/c/n
4079 We assume the following telecined stream:
4082 Top fields: 1 2 2 3 4
4083 Bottom fields: 1 2 3 4 4
4086 The numbers correspond to the progressive frame the fields relate to. Here, the
4087 first two frames are progressive, the 3rd and 4th are combed, and so on.
4089 When @code{fieldmatch} is configured to run a matching from bottom
4090 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4095 B 1 2 3 4 4 <-- matching reference
4104 As a result of the field matching, we can see that some frames get duplicated.
4105 To perform a complete inverse telecine, you need to rely on a decimation filter
4106 after this operation. See for instance the @ref{decimate} filter.
4108 The same operation now matching from top fields (@option{field}=@var{top})
4113 T 1 2 2 3 4 <-- matching reference
4123 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4124 basically, they refer to the frame and field of the opposite parity:
4127 @item @var{p} matches the field of the opposite parity in the previous frame
4128 @item @var{c} matches the field of the opposite parity in the current frame
4129 @item @var{n} matches the field of the opposite parity in the next frame
4134 The @var{u} and @var{b} matching are a bit special in the sense that they match
4135 from the opposite parity flag. In the following examples, we assume that we are
4136 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4137 'x' is placed above and below each matched fields.
4139 With bottom matching (@option{field}=@var{bottom}):
4144 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4145 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4153 With top matching (@option{field}=@var{top}):
4158 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4159 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4167 @subsection Examples
4169 Simple IVTC of a top field first telecined stream:
4171 fieldmatch=order=tff:combmatch=none, decimate
4174 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4176 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4181 Transform the field order of the input video.
4183 This filter accepts the following options:
4188 Output field order. Valid values are @var{tff} for top field first or @var{bff}
4189 for bottom field first.
4192 Default value is @samp{tff}.
4194 Transformation is achieved by shifting the picture content up or down
4195 by one line, and filling the remaining line with appropriate picture content.
4196 This method is consistent with most broadcast field order converters.
4198 If the input video is not flagged as being interlaced, or it is already
4199 flagged as being of the required output field order then this filter does
4200 not alter the incoming video.
4202 This filter is very useful when converting to or from PAL DV material,
4203 which is bottom field first.
4207 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4212 Buffer input images and send them when they are requested.
4214 This filter is mainly useful when auto-inserted by the libavfilter
4217 The filter does not take parameters.
4222 Convert the input video to one of the specified pixel formats.
4223 Libavfilter will try to pick one that is supported for the input to
4226 This filter accepts the following parameters:
4230 A '|'-separated list of pixel format names, for example
4231 "pix_fmts=yuv420p|monow|rgb24".
4235 @subsection Examples
4239 Convert the input video to the format @var{yuv420p}
4241 format=pix_fmts=yuv420p
4244 Convert the input video to any of the formats in the list
4246 format=pix_fmts=yuv420p|yuv444p|yuv410p
4252 Convert the video to specified constant frame rate by duplicating or dropping
4253 frames as necessary.
4255 This filter accepts the following named parameters:
4259 Desired output frame rate. The default is @code{25}.
4264 Possible values are:
4267 zero round towards 0
4271 round towards -infinity
4273 round towards +infinity
4277 The default is @code{near}.
4280 Assume the first PTS should be the given value, in seconds. This allows for
4281 padding/trimming at the start of stream. By default, no assumption is made
4282 about the first frame's expected PTS, so no padding or trimming is done.
4283 For example, this could be set to 0 to pad the beginning with duplicates of
4284 the first frame if a video stream starts after the audio stream or to trim any
4285 frames with a negative PTS.
4289 Alternatively, the options can be specified as a flat string:
4290 @var{fps}[:@var{round}].
4292 See also the @ref{setpts} filter.
4294 @subsection Examples
4298 A typical usage in order to set the fps to 25:
4304 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4306 fps=fps=film:round=near
4312 Select one frame every N-th frame.
4314 This filter accepts the following option:
4317 Select frame after every @code{step} frames.
4318 Allowed values are positive integers higher than 0. Default value is @code{1}.
4324 Apply a frei0r effect to the input video.
4326 To enable compilation of this filter you need to install the frei0r
4327 header and configure FFmpeg with @code{--enable-frei0r}.
4329 This filter accepts the following options:
4334 The name to the frei0r effect to load. If the environment variable
4335 @env{FREI0R_PATH} is defined, the frei0r effect is searched in each one of the
4336 directories specified by the colon separated list in @env{FREIOR_PATH},
4337 otherwise in the standard frei0r paths, which are in this order:
4338 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
4339 @file{/usr/lib/frei0r-1/}.
4342 A '|'-separated list of parameters to pass to the frei0r effect.
4346 A frei0r effect parameter can be a boolean (whose values are specified
4347 with "y" and "n"), a double, a color (specified by the syntax
4348 @var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
4349 numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
4350 description), a position (specified by the syntax @var{X}/@var{Y},
4351 @var{X} and @var{Y} being float numbers) and a string.
4353 The number and kind of parameters depend on the loaded effect. If an
4354 effect parameter is not specified the default value is set.
4356 @subsection Examples
4360 Apply the distort0r effect, set the first two double parameters:
4362 frei0r=filter_name=distort0r:filter_params=0.5|0.01
4366 Apply the colordistance effect, take a color as first parameter:
4368 frei0r=colordistance:0.2/0.3/0.4
4369 frei0r=colordistance:violet
4370 frei0r=colordistance:0x112233
4374 Apply the perspective effect, specify the top left and top right image
4377 frei0r=perspective:0.2/0.2|0.8/0.2
4381 For more information see:
4382 @url{http://frei0r.dyne.org}
4386 The filter accepts the following options:
4390 Set the luminance expression.
4392 Set the chrominance blue expression.
4394 Set the chrominance red expression.
4396 Set the alpha expression.
4398 Set the red expression.
4400 Set the green expression.
4402 Set the blue expression.
4405 The colorspace is selected according to the specified options. If one
4406 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4407 options is specified, the filter will automatically select a YCbCr
4408 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4409 @option{blue_expr} options is specified, it will select an RGB
4412 If one of the chrominance expression is not defined, it falls back on the other
4413 one. If no alpha expression is specified it will evaluate to opaque value.
4414 If none of chrominance expressions are specified, they will evaluate
4415 to the luminance expression.
4417 The expressions can use the following variables and functions:
4421 The sequential number of the filtered frame, starting from @code{0}.
4425 The coordinates of the current sample.
4429 The width and height of the image.
4433 Width and height scale depending on the currently filtered plane. It is the
4434 ratio between the corresponding luma plane number of pixels and the current
4435 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4436 @code{0.5,0.5} for chroma planes.
4439 Time of the current frame, expressed in seconds.
4442 Return the value of the pixel at location (@var{x},@var{y}) of the current
4446 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
4450 Return the value of the pixel at location (@var{x},@var{y}) of the
4451 blue-difference chroma plane. Return 0 if there is no such plane.
4454 Return the value of the pixel at location (@var{x},@var{y}) of the
4455 red-difference chroma plane. Return 0 if there is no such plane.
4460 Return the value of the pixel at location (@var{x},@var{y}) of the
4461 red/green/blue component. Return 0 if there is no such component.
4464 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
4465 plane. Return 0 if there is no such plane.
4468 For functions, if @var{x} and @var{y} are outside the area, the value will be
4469 automatically clipped to the closer edge.
4471 @subsection Examples
4475 Flip the image horizontally:
4481 Generate a bidimensional sine wave, with angle @code{PI/3} and a
4482 wavelength of 100 pixels:
4484 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
4488 Generate a fancy enigmatic moving light:
4490 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
4494 Generate a quick emboss effect:
4496 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
4500 Modify RGB components depending on pixel position:
4502 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
4508 Fix the banding artifacts that are sometimes introduced into nearly flat
4509 regions by truncation to 8bit color depth.
4510 Interpolate the gradients that should go where the bands are, and
4513 This filter is designed for playback only. Do not use it prior to
4514 lossy compression, because compression tends to lose the dither and
4515 bring back the bands.
4517 This filter accepts the following options:
4522 The maximum amount by which the filter will change any one pixel. Also the
4523 threshold for detecting nearly flat regions. Acceptable values range from .51 to
4524 64, default value is 1.2, out-of-range values will be clipped to the valid
4528 The neighborhood to fit the gradient to. A larger radius makes for smoother
4529 gradients, but also prevents the filter from modifying the pixels near detailed
4530 regions. Acceptable values are 8-32, default value is 16, out-of-range values
4531 will be clipped to the valid range.
4535 Alternatively, the options can be specified as a flat string:
4536 @var{strength}[:@var{radius}]
4538 @subsection Examples
4542 Apply the filter with a @code{3.5} strength and radius of @code{8}:
4548 Specify radius, omitting the strength (which will fall-back to the default
4559 Apply a Hald CLUT to a video stream.
4561 First input is the video stream to process, and second one is the Hald CLUT.
4562 The Hald CLUT input can be a simple picture or a complete video stream.
4564 The filter accepts the following options:
4568 Force termination when the shortest input terminates. Default is @code{0}.
4570 Continue applying the last CLUT after the end of the stream. A value of
4571 @code{0} disable the filter after the last frame of the CLUT is reached.
4572 Default is @code{1}.
4575 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
4576 filters share the same internals).
4578 More information about the Hald CLUT can be found on Eskil Steenberg's website
4579 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
4581 @subsection Workflow examples
4583 @subsubsection Hald CLUT video stream
4585 Generate an identity Hald CLUT stream altered with various effects:
4587 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
4590 Note: make sure you use a lossless codec.
4592 Then use it with @code{haldclut} to apply it on some random stream:
4594 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
4597 The Hald CLUT will be applied to the 10 first seconds (duration of
4598 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
4599 to the remaining frames of the @code{mandelbrot} stream.
4601 @subsubsection Hald CLUT with preview
4603 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
4604 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
4605 biggest possible square starting at the top left of the picture. The remaining
4606 padding pixels (bottom or right) will be ignored. This area can be used to add
4607 a preview of the Hald CLUT.
4609 Typically, the following generated Hald CLUT will be supported by the
4610 @code{haldclut} filter:
4613 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
4614 pad=iw+320 [padded_clut];
4615 smptebars=s=320x256, split [a][b];
4616 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
4617 [main][b] overlay=W-320" -frames:v 1 clut.png
4620 It contains the original and a preview of the effect of the CLUT: SMPTE color
4621 bars are displayed on the right-top, and below the same color bars processed by
4624 Then, the effect of this Hald CLUT can be visualized with:
4626 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
4631 Flip the input video horizontally.
4633 For example to horizontally flip the input video with @command{ffmpeg}:
4635 ffmpeg -i in.avi -vf "hflip" out.avi
4639 This filter applies a global color histogram equalization on a
4642 It can be used to correct video that has a compressed range of pixel
4643 intensities. The filter redistributes the pixel intensities to
4644 equalize their distribution across the intensity range. It may be
4645 viewed as an "automatically adjusting contrast filter". This filter is
4646 useful only for correcting degraded or poorly captured source
4649 The filter accepts the following options:
4653 Determine the amount of equalization to be applied. As the strength
4654 is reduced, the distribution of pixel intensities more-and-more
4655 approaches that of the input frame. The value must be a float number
4656 in the range [0,1] and defaults to 0.200.
4659 Set the maximum intensity that can generated and scale the output
4660 values appropriately. The strength should be set as desired and then
4661 the intensity can be limited if needed to avoid washing-out. The value
4662 must be a float number in the range [0,1] and defaults to 0.210.
4665 Set the antibanding level. If enabled the filter will randomly vary
4666 the luminance of output pixels by a small amount to avoid banding of
4667 the histogram. Possible values are @code{none}, @code{weak} or
4668 @code{strong}. It defaults to @code{none}.
4673 Compute and draw a color distribution histogram for the input video.
4675 The computed histogram is a representation of distribution of color components
4678 The filter accepts the following options:
4684 It accepts the following values:
4687 standard histogram that display color components distribution in an image.
4688 Displays color graph for each color component. Shows distribution
4689 of the Y, U, V, A or G, B, R components, depending on input format,
4690 in current frame. Bellow each graph is color component scale meter.
4693 chroma values in vectorscope, if brighter more such chroma values are
4694 distributed in an image.
4695 Displays chroma values (U/V color placement) in two dimensional graph
4696 (which is called a vectorscope). It can be used to read of the hue and
4697 saturation of the current frame. At a same time it is a histogram.
4698 The whiter a pixel in the vectorscope, the more pixels of the input frame
4699 correspond to that pixel (that is the more pixels have this chroma value).
4700 The V component is displayed on the horizontal (X) axis, with the leftmost
4701 side being V = 0 and the rightmost side being V = 255.
4702 The U component is displayed on the vertical (Y) axis, with the top
4703 representing U = 0 and the bottom representing U = 255.
4705 The position of a white pixel in the graph corresponds to the chroma value
4706 of a pixel of the input clip. So the graph can be used to read of the
4707 hue (color flavor) and the saturation (the dominance of the hue in the color).
4708 As the hue of a color changes, it moves around the square. At the center of
4709 the square, the saturation is zero, which means that the corresponding pixel
4710 has no color. If you increase the amount of a specific color, while leaving
4711 the other colors unchanged, the saturation increases, and you move towards
4712 the edge of the square.
4715 chroma values in vectorscope, similar as @code{color} but actual chroma values
4719 per row/column color component graph. In row mode graph in the left side represents
4720 color component value 0 and right side represents value = 255. In column mode top
4721 side represents color component value = 0 and bottom side represents value = 255.
4723 Default value is @code{levels}.
4726 Set height of level in @code{levels}. Default value is @code{200}.
4727 Allowed range is [50, 2048].
4730 Set height of color scale in @code{levels}. Default value is @code{12}.
4731 Allowed range is [0, 40].
4734 Set step for @code{waveform} mode. Smaller values are useful to find out how much
4735 of same luminance values across input rows/columns are distributed.
4736 Default value is @code{10}. Allowed range is [1, 255].
4739 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
4740 Default is @code{row}.
4743 Set display mode for @code{waveform} and @code{levels}.
4744 It accepts the following values:
4747 Display separate graph for the color components side by side in
4748 @code{row} waveform mode or one below other in @code{column} waveform mode
4749 for @code{waveform} histogram mode. For @code{levels} histogram mode
4750 per color component graphs are placed one bellow other.
4752 This display mode in @code{waveform} histogram mode makes it easy to spot
4753 color casts in the highlights and shadows of an image, by comparing the
4754 contours of the top and the bottom of each waveform.
4755 Since whites, grays, and blacks are characterized by
4756 exactly equal amounts of red, green, and blue, neutral areas of the
4757 picture should display three waveforms of roughly equal width/height.
4758 If not, the correction is easy to make by making adjustments to level the
4762 Presents information that's identical to that in the @code{parade}, except
4763 that the graphs representing color components are superimposed directly
4766 This display mode in @code{waveform} histogram mode can make it easier to spot
4767 the relative differences or similarities in overlapping areas of the color
4768 components that are supposed to be identical, such as neutral whites, grays,
4771 Default is @code{parade}.
4774 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
4775 Default is @code{linear}.
4778 @subsection Examples
4783 Calculate and draw histogram:
4785 ffplay -i input -vf histogram
4793 High precision/quality 3d denoise filter. This filter aims to reduce
4794 image noise producing smooth images and making still images really
4795 still. It should enhance compressibility.
4797 It accepts the following optional parameters:
4801 a non-negative float number which specifies spatial luma strength,
4804 @item chroma_spatial
4805 a non-negative float number which specifies spatial chroma strength,
4806 defaults to 3.0*@var{luma_spatial}/4.0
4809 a float number which specifies luma temporal strength, defaults to
4810 6.0*@var{luma_spatial}/4.0
4813 a float number which specifies chroma temporal strength, defaults to
4814 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
4819 Modify the hue and/or the saturation of the input.
4821 This filter accepts the following options:
4825 Specify the hue angle as a number of degrees. It accepts an expression,
4826 and defaults to "0".
4829 Specify the saturation in the [-10,10] range. It accepts an expression and
4833 Specify the hue angle as a number of radians. It accepts an
4834 expression, and defaults to "0".
4837 Specify the brightness in the [-10,10] range. It accepts an expression and
4841 @option{h} and @option{H} are mutually exclusive, and can't be
4842 specified at the same time.
4844 The @option{b}, @option{h}, @option{H} and @option{s} option values are
4845 expressions containing the following constants:
4849 frame count of the input frame starting from 0
4852 presentation timestamp of the input frame expressed in time base units
4855 frame rate of the input video, NAN if the input frame rate is unknown
4858 timestamp expressed in seconds, NAN if the input timestamp is unknown
4861 time base of the input video
4864 @subsection Examples
4868 Set the hue to 90 degrees and the saturation to 1.0:
4874 Same command but expressing the hue in radians:
4880 Rotate hue and make the saturation swing between 0
4881 and 2 over a period of 1 second:
4883 hue="H=2*PI*t: s=sin(2*PI*t)+1"
4887 Apply a 3 seconds saturation fade-in effect starting at 0:
4892 The general fade-in expression can be written as:
4894 hue="s=min(0\, max((t-START)/DURATION\, 1))"
4898 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
4900 hue="s=max(0\, min(1\, (8-t)/3))"
4903 The general fade-out expression can be written as:
4905 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
4910 @subsection Commands
4912 This filter supports the following commands:
4918 Modify the hue and/or the saturation and/or brightness of the input video.
4919 The command accepts the same syntax of the corresponding option.
4921 If the specified expression is not valid, it is kept at its current
4927 Detect video interlacing type.
4929 This filter tries to detect if the input is interlaced or progressive,
4930 top or bottom field first.
4932 The filter accepts the following options:
4936 Set interlacing threshold.
4938 Set progressive threshold.
4943 Deinterleave or interleave fields.
4945 This filter allows to process interlaced images fields without
4946 deinterlacing them. Deinterleaving splits the input frame into 2
4947 fields (so called half pictures). Odd lines are moved to the top
4948 half of the output image, even lines to the bottom half.
4949 You can process (filter) them independently and then re-interleave them.
4951 The filter accepts the following options:
4955 @item chroma_mode, c
4957 Available values for @var{luma_mode}, @var{chroma_mode} and
4958 @var{alpha_mode} are:
4964 @item deinterleave, d
4965 Deinterleave fields, placing one above the other.
4968 Interleave fields. Reverse the effect of deinterleaving.
4970 Default value is @code{none}.
4973 @item chroma_swap, cs
4974 @item alpha_swap, as
4975 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
4980 Simple interlacing filter from progressive contents. This interleaves upper (or
4981 lower) lines from odd frames with lower (or upper) lines from even frames,
4982 halving the frame rate and preserving image height.
4985 Original Original New Frame
4986 Frame 'j' Frame 'j+1' (tff)
4987 ========== =========== ==================
4988 Line 0 --------------------> Frame 'j' Line 0
4989 Line 1 Line 1 ----> Frame 'j+1' Line 1
4990 Line 2 ---------------------> Frame 'j' Line 2
4991 Line 3 Line 3 ----> Frame 'j+1' Line 3
4993 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
4996 It accepts the following optional parameters:
5000 determines whether the interlaced frame is taken from the even (tff - default)
5001 or odd (bff) lines of the progressive frame.
5004 Enable (default) or disable the vertical lowpass filter to avoid twitter
5005 interlacing and reduce moire patterns.
5010 Deinterlace input video by applying Donald Graft's adaptive kernel
5011 deinterling. Work on interlaced parts of a video to produce
5014 The description of the accepted parameters follows.
5018 Set the threshold which affects the filter's tolerance when
5019 determining if a pixel line must be processed. It must be an integer
5020 in the range [0,255] and defaults to 10. A value of 0 will result in
5021 applying the process on every pixels.
5024 Paint pixels exceeding the threshold value to white if set to 1.
5028 Set the fields order. Swap fields if set to 1, leave fields alone if
5032 Enable additional sharpening if set to 1. Default is 0.
5035 Enable twoway sharpening if set to 1. Default is 0.
5038 @subsection Examples
5042 Apply default values:
5044 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5048 Enable additional sharpening:
5054 Paint processed pixels in white:
5063 Apply a 3D LUT to an input video.
5065 The filter accepts the following options:
5069 Set the 3D LUT file name.
5071 Currently supported formats:
5083 Select interpolation mode.
5085 Available values are:
5089 Use values from the nearest defined point.
5091 Interpolate values using the 8 points defining a cube.
5093 Interpolate values using a tetrahedron.
5097 @section lut, lutrgb, lutyuv
5099 Compute a look-up table for binding each pixel component input value
5100 to an output value, and apply it to input video.
5102 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5103 to an RGB input video.
5105 These filters accept the following options:
5108 set first pixel component expression
5110 set second pixel component expression
5112 set third pixel component expression
5114 set fourth pixel component expression, corresponds to the alpha component
5117 set red component expression
5119 set green component expression
5121 set blue component expression
5123 alpha component expression
5126 set Y/luminance component expression
5128 set U/Cb component expression
5130 set V/Cr component expression
5133 Each of them specifies the expression to use for computing the lookup table for
5134 the corresponding pixel component values.
5136 The exact component associated to each of the @var{c*} options depends on the
5139 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5140 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5142 The expressions can contain the following constants and functions:
5147 the input width and height
5150 input value for the pixel component
5153 the input value clipped in the @var{minval}-@var{maxval} range
5156 maximum value for the pixel component
5159 minimum value for the pixel component
5162 the negated value for the pixel component value clipped in the
5163 @var{minval}-@var{maxval} range , it corresponds to the expression
5164 "maxval-clipval+minval"
5167 the computed value in @var{val} clipped in the
5168 @var{minval}-@var{maxval} range
5170 @item gammaval(gamma)
5171 the computed gamma correction value of the pixel component value
5172 clipped in the @var{minval}-@var{maxval} range, corresponds to the
5174 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
5178 All expressions default to "val".
5180 @subsection Examples
5186 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
5187 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
5190 The above is the same as:
5192 lutrgb="r=negval:g=negval:b=negval"
5193 lutyuv="y=negval:u=negval:v=negval"
5203 Remove chroma components, turns the video into a graytone image:
5205 lutyuv="u=128:v=128"
5209 Apply a luma burning effect:
5215 Remove green and blue components:
5221 Set a constant alpha channel value on input:
5223 format=rgba,lutrgb=a="maxval-minval/2"
5227 Correct luminance gamma by a 0.5 factor:
5229 lutyuv=y=gammaval(0.5)
5233 Discard least significant bits of luma:
5235 lutyuv=y='bitand(val, 128+64+32)'
5241 Apply motion-compensation deinterlacing.
5243 It needs one field per frame as input and must thus be used together
5244 with yadif=1/3 or equivalent.
5246 This filter accepts the following options:
5249 Set the deinterlacing mode.
5251 It accepts one of the following values:
5256 use iterative motion estimation
5258 like @samp{slow}, but use multiple reference frames.
5260 Default value is @samp{fast}.
5263 Set the picture field parity assumed for the input video. It must be
5264 one of the following values:
5268 assume top field first
5270 assume bottom field first
5273 Default value is @samp{bff}.
5276 Set per-block quantization parameter (QP) used by the internal
5279 Higher values should result in a smoother motion vector field but less
5280 optimal individual vectors. Default value is 1.
5285 Apply an MPlayer filter to the input video.
5287 This filter provides a wrapper around some of the filters of
5290 This wrapper is considered experimental. Some of the wrapped filters
5291 may not work properly and we may drop support for them, as they will
5292 be implemented natively into FFmpeg. Thus you should avoid
5293 depending on them when writing portable scripts.
5295 The filter accepts the parameters:
5296 @var{filter_name}[:=]@var{filter_params}
5298 @var{filter_name} is the name of a supported MPlayer filter,
5299 @var{filter_params} is a string containing the parameters accepted by
5302 The list of the currently supported filters follows:
5313 The parameter syntax and behavior for the listed filters are the same
5314 of the corresponding MPlayer filters. For detailed instructions check
5315 the "VIDEO FILTERS" section in the MPlayer manual.
5317 @subsection Examples
5321 Adjust gamma, brightness, contrast:
5327 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
5331 Drop frames that do not differ greatly from the previous frame in
5332 order to reduce frame rate.
5334 The main use of this filter is for very-low-bitrate encoding
5335 (e.g. streaming over dialup modem), but it could in theory be used for
5336 fixing movies that were inverse-telecined incorrectly.
5338 A description of the accepted options follows.
5342 Set the maximum number of consecutive frames which can be dropped (if
5343 positive), or the minimum interval between dropped frames (if
5344 negative). If the value is 0, the frame is dropped unregarding the
5345 number of previous sequentially dropped frames.
5352 Set the dropping threshold values.
5354 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
5355 represent actual pixel value differences, so a threshold of 64
5356 corresponds to 1 unit of difference for each pixel, or the same spread
5357 out differently over the block.
5359 A frame is a candidate for dropping if no 8x8 blocks differ by more
5360 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
5361 meaning the whole image) differ by more than a threshold of @option{lo}.
5363 Default value for @option{hi} is 64*12, default value for @option{lo} is
5364 64*5, and default value for @option{frac} is 0.33.
5372 This filter accepts an integer in input, if non-zero it negates the
5373 alpha component (if available). The default value in input is 0.
5377 Force libavfilter not to use any of the specified pixel formats for the
5378 input to the next filter.
5380 This filter accepts the following parameters:
5384 A '|'-separated list of pixel format names, for example
5385 "pix_fmts=yuv420p|monow|rgb24".
5389 @subsection Examples
5393 Force libavfilter to use a format different from @var{yuv420p} for the
5394 input to the vflip filter:
5396 noformat=pix_fmts=yuv420p,vflip
5400 Convert the input video to any of the formats not contained in the list:
5402 noformat=yuv420p|yuv444p|yuv410p
5408 Add noise on video input frame.
5410 The filter accepts the following options:
5418 Set noise seed for specific pixel component or all pixel components in case
5419 of @var{all_seed}. Default value is @code{123457}.
5421 @item all_strength, alls
5422 @item c0_strength, c0s
5423 @item c1_strength, c1s
5424 @item c2_strength, c2s
5425 @item c3_strength, c3s
5426 Set noise strength for specific pixel component or all pixel components in case
5427 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
5429 @item all_flags, allf
5434 Set pixel component flags or set flags for all components if @var{all_flags}.
5435 Available values for component flags are:
5438 averaged temporal noise (smoother)
5440 mix random noise with a (semi)regular pattern
5442 temporal noise (noise pattern changes between frames)
5444 uniform noise (gaussian otherwise)
5448 @subsection Examples
5450 Add temporal and uniform noise to input video:
5452 noise=alls=20:allf=t+u
5457 Pass the video source unchanged to the output.
5461 Apply video transform using libopencv.
5463 To enable this filter install libopencv library and headers and
5464 configure FFmpeg with @code{--enable-libopencv}.
5466 This filter accepts the following parameters:
5471 The name of the libopencv filter to apply.
5474 The parameters to pass to the libopencv filter. If not specified the default
5479 Refer to the official libopencv documentation for more precise
5481 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
5483 Follows the list of supported libopencv filters.
5488 Dilate an image by using a specific structuring element.
5489 This filter corresponds to the libopencv function @code{cvDilate}.
5491 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
5493 @var{struct_el} represents a structuring element, and has the syntax:
5494 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
5496 @var{cols} and @var{rows} represent the number of columns and rows of
5497 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
5498 point, and @var{shape} the shape for the structuring element, and
5499 can be one of the values "rect", "cross", "ellipse", "custom".
5501 If the value for @var{shape} is "custom", it must be followed by a
5502 string of the form "=@var{filename}". The file with name
5503 @var{filename} is assumed to represent a binary image, with each
5504 printable character corresponding to a bright pixel. When a custom
5505 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
5506 or columns and rows of the read file are assumed instead.
5508 The default value for @var{struct_el} is "3x3+0x0/rect".
5510 @var{nb_iterations} specifies the number of times the transform is
5511 applied to the image, and defaults to 1.
5513 Follow some example:
5515 # use the default values
5518 # dilate using a structuring element with a 5x5 cross, iterate two times
5519 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
5521 # read the shape from the file diamond.shape, iterate two times
5522 # the file diamond.shape may contain a pattern of characters like this:
5528 # the specified cols and rows are ignored (but not the anchor point coordinates)
5529 ocv=dilate:0x0+2x2/custom=diamond.shape|2
5534 Erode an image by using a specific structuring element.
5535 This filter corresponds to the libopencv function @code{cvErode}.
5537 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
5538 with the same syntax and semantics as the @ref{dilate} filter.
5542 Smooth the input video.
5544 The filter takes the following parameters:
5545 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
5547 @var{type} is the type of smooth filter to apply, and can be one of
5548 the following values: "blur", "blur_no_scale", "median", "gaussian",
5549 "bilateral". The default value is "gaussian".
5551 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
5552 parameters whose meanings depend on smooth type. @var{param1} and
5553 @var{param2} accept integer positive values or 0, @var{param3} and
5554 @var{param4} accept float values.
5556 The default value for @var{param1} is 3, the default value for the
5557 other parameters is 0.
5559 These parameters correspond to the parameters assigned to the
5560 libopencv function @code{cvSmooth}.
5565 Overlay one video on top of another.
5567 It takes two inputs and one output, the first input is the "main"
5568 video on which the second input is overlayed.
5570 This filter accepts the following parameters:
5572 A description of the accepted options follows.
5577 Set the expression for the x and y coordinates of the overlayed video
5578 on the main video. Default value is "0" for both expressions. In case
5579 the expression is invalid, it is set to a huge value (meaning that the
5580 overlay will not be displayed within the output visible area).
5583 Set when the expressions for @option{x}, and @option{y} are evaluated.
5585 It accepts the following values:
5588 only evaluate expressions once during the filter initialization or
5589 when a command is processed
5592 evaluate expressions for each incoming frame
5595 Default value is @samp{frame}.
5598 If set to 1, force the output to terminate when the shortest input
5599 terminates. Default value is 0.
5602 Set the format for the output video.
5604 It accepts the following values:
5616 Default value is @samp{yuv420}.
5618 @item rgb @emph{(deprecated)}
5619 If set to 1, force the filter to accept inputs in the RGB
5620 color space. Default value is 0. This option is deprecated, use
5621 @option{format} instead.
5624 If set to 1, force the filter to draw the last overlay frame over the
5625 main input until the end of the stream. A value of 0 disables this
5626 behavior. Default value is 1.
5629 The @option{x}, and @option{y} expressions can contain the following
5635 main input width and height
5639 overlay input width and height
5643 the computed values for @var{x} and @var{y}. They are evaluated for
5648 horizontal and vertical chroma subsample values of the output
5649 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
5653 the number of input frame, starting from 0
5656 the position in the file of the input frame, NAN if unknown
5659 timestamp expressed in seconds, NAN if the input timestamp is unknown
5662 Note that the @var{n}, @var{pos}, @var{t} variables are available only
5663 when evaluation is done @emph{per frame}, and will evaluate to NAN
5664 when @option{eval} is set to @samp{init}.
5666 Be aware that frames are taken from each input video in timestamp
5667 order, hence, if their initial timestamps differ, it is a good idea
5668 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
5669 have them begin in the same zero timestamp, as it does the example for
5670 the @var{movie} filter.
5672 You can chain together more overlays but you should test the
5673 efficiency of such approach.
5675 @subsection Commands
5677 This filter supports the following commands:
5681 Modify the x and y of the overlay input.
5682 The command accepts the same syntax of the corresponding option.
5684 If the specified expression is not valid, it is kept at its current
5688 @subsection Examples
5692 Draw the overlay at 10 pixels from the bottom right corner of the main
5695 overlay=main_w-overlay_w-10:main_h-overlay_h-10
5698 Using named options the example above becomes:
5700 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
5704 Insert a transparent PNG logo in the bottom left corner of the input,
5705 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
5707 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
5711 Insert 2 different transparent PNG logos (second logo on bottom
5712 right corner) using the @command{ffmpeg} tool:
5714 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
5718 Add a transparent color layer on top of the main video, @code{WxH}
5719 must specify the size of the main input to the overlay filter:
5721 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
5725 Play an original video and a filtered version (here with the deshake
5726 filter) side by side using the @command{ffplay} tool:
5728 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
5731 The above command is the same as:
5733 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
5737 Make a sliding overlay appearing from the left to the right top part of the
5738 screen starting since time 2:
5740 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
5744 Compose output by putting two input videos side to side:
5746 ffmpeg -i left.avi -i right.avi -filter_complex "
5747 nullsrc=size=200x100 [background];
5748 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
5749 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
5750 [background][left] overlay=shortest=1 [background+left];
5751 [background+left][right] overlay=shortest=1:x=100 [left+right]
5756 Chain several overlays in cascade:
5758 nullsrc=s=200x200 [bg];
5759 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
5760 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
5761 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
5762 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
5763 [in3] null, [mid2] overlay=100:100 [out0]
5770 Apply Overcomplete Wavelet denoiser.
5772 The filter accepts the following options:
5778 Larger depth values will denoise lower frequency components more, but
5779 slow down filtering.
5781 Must be an int in the range 8-16, default is @code{8}.
5783 @item luma_strength, ls
5786 Must be a double value in the range 0-1000, default is @code{1.0}.
5788 @item chroma_strength, cs
5789 Set chroma strength.
5791 Must be a double value in the range 0-1000, default is @code{1.0}.
5796 Add paddings to the input image, and place the original input at the
5797 given coordinates @var{x}, @var{y}.
5799 This filter accepts the following parameters:
5804 Specify an expression for the size of the output image with the
5805 paddings added. If the value for @var{width} or @var{height} is 0, the
5806 corresponding input size is used for the output.
5808 The @var{width} expression can reference the value set by the
5809 @var{height} expression, and vice versa.
5811 The default value of @var{width} and @var{height} is 0.
5815 Specify an expression for the offsets where to place the input image
5816 in the padded area with respect to the top/left border of the output
5819 The @var{x} expression can reference the value set by the @var{y}
5820 expression, and vice versa.
5822 The default value of @var{x} and @var{y} is 0.
5825 Specify the color of the padded area, it can be the name of a color
5826 (case insensitive match) or a 0xRRGGBB[AA] sequence.
5828 The default value of @var{color} is "black".
5831 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
5832 options are expressions containing the following constants:
5837 the input video width and height
5841 same as @var{in_w} and @var{in_h}
5845 the output width and height, that is the size of the padded area as
5846 specified by the @var{width} and @var{height} expressions
5850 same as @var{out_w} and @var{out_h}
5854 x and y offsets as specified by the @var{x} and @var{y}
5855 expressions, or NAN if not yet specified
5858 same as @var{iw} / @var{ih}
5861 input sample aspect ratio
5864 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
5868 horizontal and vertical chroma subsample values. For example for the
5869 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
5872 @subsection Examples
5876 Add paddings with color "violet" to the input video. Output video
5877 size is 640x480, the top-left corner of the input video is placed at
5880 pad=640:480:0:40:violet
5883 The example above is equivalent to the following command:
5885 pad=width=640:height=480:x=0:y=40:color=violet
5889 Pad the input to get an output with dimensions increased by 3/2,
5890 and put the input video at the center of the padded area:
5892 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
5896 Pad the input to get a squared output with size equal to the maximum
5897 value between the input width and height, and put the input video at
5898 the center of the padded area:
5900 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
5904 Pad the input to get a final w/h ratio of 16:9:
5906 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
5910 In case of anamorphic video, in order to set the output display aspect
5911 correctly, it is necessary to use @var{sar} in the expression,
5912 according to the relation:
5914 (ih * X / ih) * sar = output_dar
5915 X = output_dar / sar
5918 Thus the previous example needs to be modified to:
5920 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
5924 Double output size and put the input video in the bottom-right
5925 corner of the output padded area:
5927 pad="2*iw:2*ih:ow-iw:oh-ih"
5931 @section perspective
5933 Correct perspective of video not recorded perpendicular to the screen.
5935 A description of the accepted parameters follows.
5946 Set coordinates expression for top left, top right, bottom left and bottom right corners.
5947 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
5949 The expressions can use the following variables:
5954 the width and height of video frame.
5958 Set interpolation for perspective correction.
5960 It accepts the following values:
5966 Default value is @samp{linear}.
5971 Delay interlaced video by one field time so that the field order changes.
5973 The intended use is to fix PAL movies that have been captured with the
5974 opposite field order to the film-to-video transfer.
5976 A description of the accepted parameters follows.
5982 It accepts the following values:
5985 Capture field order top-first, transfer bottom-first.
5986 Filter will delay the bottom field.
5989 Capture field order bottom-first, transfer top-first.
5990 Filter will delay the top field.
5993 Capture and transfer with the same field order. This mode only exists
5994 for the documentation of the other options to refer to, but if you
5995 actually select it, the filter will faithfully do nothing.
5998 Capture field order determined automatically by field flags, transfer
6000 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6001 basis using field flags. If no field information is available,
6002 then this works just like @samp{u}.
6005 Capture unknown or varying, transfer opposite.
6006 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6007 analyzing the images and selecting the alternative that produces best
6008 match between the fields.
6011 Capture top-first, transfer unknown or varying.
6012 Filter selects among @samp{t} and @samp{p} using image analysis.
6015 Capture bottom-first, transfer unknown or varying.
6016 Filter selects among @samp{b} and @samp{p} using image analysis.
6019 Capture determined by field flags, transfer unknown or varying.
6020 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6021 image analysis. If no field information is available, then this works just
6022 like @samp{U}. This is the default mode.
6025 Both capture and transfer unknown or varying.
6026 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
6030 @section pixdesctest
6032 Pixel format descriptor test filter, mainly useful for internal
6033 testing. The output video should be equal to the input video.
6037 format=monow, pixdesctest
6040 can be used to test the monowhite pixel format descriptor definition.
6044 Enable the specified chain of postprocessing subfilters using libpostproc. This
6045 library should be automatically selected with a GPL build (@code{--enable-gpl}).
6046 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
6047 Each subfilter and some options have a short and a long name that can be used
6048 interchangeably, i.e. dr/dering are the same.
6050 The filters accept the following options:
6054 Set postprocessing subfilters string.
6057 All subfilters share common options to determine their scope:
6061 Honor the quality commands for this subfilter.
6064 Do chrominance filtering, too (default).
6067 Do luminance filtering only (no chrominance).
6070 Do chrominance filtering only (no luminance).
6073 These options can be appended after the subfilter name, separated by a '|'.
6075 Available subfilters are:
6078 @item hb/hdeblock[|difference[|flatness]]
6079 Horizontal deblocking filter
6082 Difference factor where higher values mean more deblocking (default: @code{32}).
6084 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6087 @item vb/vdeblock[|difference[|flatness]]
6088 Vertical deblocking filter
6091 Difference factor where higher values mean more deblocking (default: @code{32}).
6093 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6096 @item ha/hadeblock[|difference[|flatness]]
6097 Accurate horizontal deblocking filter
6100 Difference factor where higher values mean more deblocking (default: @code{32}).
6102 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6105 @item va/vadeblock[|difference[|flatness]]
6106 Accurate vertical deblocking filter
6109 Difference factor where higher values mean more deblocking (default: @code{32}).
6111 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6115 The horizontal and vertical deblocking filters share the difference and
6116 flatness values so you cannot set different horizontal and vertical
6121 Experimental horizontal deblocking filter
6124 Experimental vertical deblocking filter
6129 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
6132 larger -> stronger filtering
6134 larger -> stronger filtering
6136 larger -> stronger filtering
6139 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
6142 Stretch luminance to @code{0-255}.
6145 @item lb/linblenddeint
6146 Linear blend deinterlacing filter that deinterlaces the given block by
6147 filtering all lines with a @code{(1 2 1)} filter.
6149 @item li/linipoldeint
6150 Linear interpolating deinterlacing filter that deinterlaces the given block by
6151 linearly interpolating every second line.
6153 @item ci/cubicipoldeint
6154 Cubic interpolating deinterlacing filter deinterlaces the given block by
6155 cubically interpolating every second line.
6157 @item md/mediandeint
6158 Median deinterlacing filter that deinterlaces the given block by applying a
6159 median filter to every second line.
6161 @item fd/ffmpegdeint
6162 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
6163 second line with a @code{(-1 4 2 4 -1)} filter.
6166 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
6167 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
6169 @item fq/forceQuant[|quantizer]
6170 Overrides the quantizer table from the input with the constant quantizer you
6178 Default pp filter combination (@code{hb|a,vb|a,dr|a})
6181 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
6184 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
6187 @subsection Examples
6191 Apply horizontal and vertical deblocking, deringing and automatic
6192 brightness/contrast:
6198 Apply default filters without brightness/contrast correction:
6204 Apply default filters and temporal denoiser:
6206 pp=default/tmpnoise|1|2|3
6210 Apply deblocking on luminance only, and switch vertical deblocking on or off
6211 automatically depending on available CPU time:
6219 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
6220 Ratio) between two input videos.
6222 This filter takes in input two input videos, the first input is
6223 considered the "main" source and is passed unchanged to the
6224 output. The second input is used as a "reference" video for computing
6227 Both video inputs must have the same resolution and pixel format for
6228 this filter to work correctly. Also it assumes that both inputs
6229 have the same number of frames, which are compared one by one.
6231 The obtained average PSNR is printed through the logging system.
6233 The filter stores the accumulated MSE (mean squared error) of each
6234 frame, and at the end of the processing it is averaged across all frames
6235 equally, and the following formula is applied to obtain the PSNR:
6238 PSNR = 10*log10(MAX^2/MSE)
6241 Where MAX is the average of the maximum values of each component of the
6244 The description of the accepted parameters follows.
6248 If specified the filter will use the named file to save the PSNR of
6249 each individual frame.
6252 The file printed if @var{stats_file} is selected, contains a sequence of
6253 key/value pairs of the form @var{key}:@var{value} for each compared
6256 A description of each shown parameter follows:
6260 sequential number of the input frame, starting from 1
6263 Mean Square Error pixel-by-pixel average difference of the compared
6264 frames, averaged over all the image components.
6266 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
6267 Mean Square Error pixel-by-pixel average difference of the compared
6268 frames for the component specified by the suffix.
6270 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
6271 Peak Signal to Noise ratio of the compared frames for the component
6272 specified by the suffix.
6277 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
6278 [main][ref] psnr="stats_file=stats.log" [out]
6281 On this example the input file being processed is compared with the
6282 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
6283 is stored in @file{stats.log}.
6287 Pulldown reversal (inverse telecine) filter, capable of handling mixed
6288 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
6291 The pullup filter is designed to take advantage of future context in making
6292 its decisions. This filter is stateless in the sense that it does not lock
6293 onto a pattern to follow, but it instead looks forward to the following
6294 fields in order to identify matches and rebuild progressive frames.
6296 To produce content with an even framerate, insert the fps filter after
6297 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
6298 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
6300 The filter accepts the following options:
6307 These options set the amount of "junk" to ignore at the left, right, top, and
6308 bottom of the image, respectively. Left and right are in units of 8 pixels,
6309 while top and bottom are in units of 2 lines.
6310 The default is 8 pixels on each side.
6313 Set the strict breaks. Setting this option to 1 will reduce the chances of
6314 filter generating an occasional mismatched frame, but it may also cause an
6315 excessive number of frames to be dropped during high motion sequences.
6316 Conversely, setting it to -1 will make filter match fields more easily.
6317 This may help processing of video where there is slight blurring between
6318 the fields, but may also cause there to be interlaced frames in the output.
6319 Default value is @code{0}.
6322 Set the metric plane to use. It accepts the following values:
6328 Use chroma blue plane.
6331 Use chroma red plane.
6334 This option may be set to use chroma plane instead of the default luma plane
6335 for doing filter's computations. This may improve accuracy on very clean
6336 source material, but more likely will decrease accuracy, especially if there
6337 is chroma noise (rainbow effect) or any grayscale video.
6338 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
6339 load and make pullup usable in realtime on slow machines.
6342 For example to inverse telecined NTSC input:
6344 pullup,fps=24000/1001
6349 Suppress a TV station logo, using an image file to determine which
6350 pixels comprise the logo. It works by filling in the pixels that
6351 comprise the logo with neighboring pixels.
6353 The filter accepts the following options:
6357 Set the filter bitmap file, which can be any image format supported by
6358 libavformat. The width and height of the image file must match those of the
6359 video stream being processed.
6362 Pixels in the provided bitmap image with a value of zero are not
6363 considered part of the logo, non-zero pixels are considered part of
6364 the logo. If you use white (255) for the logo and black (0) for the
6365 rest, you will be safe. For making the filter bitmap, it is
6366 recommended to take a screen capture of a black frame with the logo
6367 visible, and then using a threshold filter followed by the erode
6368 filter once or twice.
6370 If needed, little splotches can be fixed manually. Remember that if
6371 logo pixels are not covered, the filter quality will be much
6372 reduced. Marking too many pixels as part of the logo does not hurt as
6373 much, but it will increase the amount of blurring needed to cover over
6374 the image and will destroy more information than necessary, and extra
6375 pixels will slow things down on a large logo.
6379 Rotate video by an arbitrary angle expressed in radians.
6381 The filter accepts the following options:
6383 A description of the optional parameters follows.
6386 Set an expression for the angle by which to rotate the input video
6387 clockwise, expressed as a number of radians. A negative value will
6388 result in a counter-clockwise rotation. By default it is set to "0".
6390 This expression is evaluated for each frame.
6393 Set the output width expression, default value is "iw".
6394 This expression is evaluated just once during configuration.
6397 Set the output height expression, default value is "ih".
6398 This expression is evaluated just once during configuration.
6401 Enable bilinear interpolation if set to 1, a value of 0 disables
6402 it. Default value is 1.
6405 Set the color used to fill the output area not covered by the rotated
6406 image. If the special value "none" is selected then no background is
6407 printed (useful for example if the background is never shown). Default
6411 The expressions for the angle and the output size can contain the
6412 following constants and functions:
6416 sequential number of the input frame, starting from 0. It is always NAN
6417 before the first frame is filtered.
6420 time in seconds of the input frame, it is set to 0 when the filter is
6421 configured. It is always NAN before the first frame is filtered.
6425 horizontal and vertical chroma subsample values. For example for the
6426 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6430 the input video width and heigth
6434 the output width and heigth, that is the size of the padded area as
6435 specified by the @var{width} and @var{height} expressions
6439 the minimal width/height required for completely containing the input
6440 video rotated by @var{a} radians.
6442 These are only available when computing the @option{out_w} and
6443 @option{out_h} expressions.
6446 @subsection Examples
6450 Rotate the input by PI/6 radians clockwise:
6456 Rotate the input by PI/6 radians counter-clockwise:
6462 Apply a constant rotation with period T, starting from an angle of PI/3:
6464 rotate=PI/3+2*PI*t/T
6468 Make the input video rotation oscillating with a period of T
6469 seconds and an amplitude of A radians:
6471 rotate=A*sin(2*PI/T*t)
6475 Rotate the video, output size is choosen so that the whole rotating
6476 input video is always completely contained in the output:
6478 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
6482 Rotate the video, reduce the output size so that no background is ever
6485 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
6489 @subsection Commands
6491 The filter supports the following commands:
6495 Set the angle expression.
6496 The command accepts the same syntax of the corresponding option.
6498 If the specified expression is not valid, it is kept at its current
6504 Apply Shape Adaptive Blur.
6506 The filter accepts the following options:
6509 @item luma_radius, lr
6510 Set luma blur filter strength, must be a value in range 0.1-4.0, default
6511 value is 1.0. A greater value will result in a more blurred image, and
6512 in slower processing.
6514 @item luma_pre_filter_radius, lpfr
6515 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
6518 @item luma_strength, ls
6519 Set luma maximum difference between pixels to still be considered, must
6520 be a value in the 0.1-100.0 range, default value is 1.0.
6522 @item chroma_radius, cr
6523 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
6524 greater value will result in a more blurred image, and in slower
6527 @item chroma_pre_filter_radius, cpfr
6528 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
6530 @item chroma_strength, cs
6531 Set chroma maximum difference between pixels to still be considered,
6532 must be a value in the 0.1-100.0 range.
6535 Each chroma option value, if not explicitly specified, is set to the
6536 corresponding luma option value.
6540 Scale (resize) the input video, using the libswscale library.
6542 The scale filter forces the output display aspect ratio to be the same
6543 of the input, by changing the output sample aspect ratio.
6545 If the input image format is different from the format requested by
6546 the next filter, the scale filter will convert the input to the
6550 The filter accepts the following options:
6555 Set the output video dimension expression. Default value is the input
6558 If the value is 0, the input width is used for the output.
6560 If one of the values is -1, the scale filter will use a value that
6561 maintains the aspect ratio of the input image, calculated from the
6562 other specified dimension. If both of them are -1, the input size is
6565 See below for the list of accepted constants for use in the dimension
6569 Set the interlacing mode. It accepts the following values:
6573 Force interlaced aware scaling.
6576 Do not apply interlaced scaling.
6579 Select interlaced aware scaling depending on whether the source frames
6580 are flagged as interlaced or not.
6583 Default value is @samp{0}.
6586 Set libswscale scaling flags. If not explictly specified the filter
6587 applies a bilinear scaling algorithm.
6590 Set the video size, the value must be a valid abbreviation or in the
6591 form @var{width}x@var{height}.
6593 @item in_color_matrix
6594 @item out_color_matrix
6595 Set in/output YCbCr color space type.
6597 This allows the autodetected value to be overridden as well as allows forcing
6598 a specific value used for the output and encoder.
6600 If not specified, the color space type depends on the pixel format.
6606 Choose automatically.
6609 Format conforming to International Telecommunication Union (ITU)
6610 Recommendation BT.709.
6613 Set color space conforming to the United States Federal Communications
6614 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
6617 Set color space conforming to:
6621 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
6624 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
6627 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
6632 Set color space conforming to SMPTE ST 240:1999.
6637 Set in/output YCbCr sample range.
6639 This allows the autodetected value to be overridden as well as allows forcing
6640 a specific value used for the output and encoder. If not specified, the
6641 range depends on the pixel format. Possible values:
6645 Choose automatically.
6648 Set full range (0-255 in case of 8-bit luma).
6651 Set "MPEG" range (16-235 in case of 8-bit luma).
6655 Set the dithering algorithm
6659 Choose automatically.
6668 error diffusion dither
6671 @item force_original_aspect_ratio
6672 Enable decreasing or increasing output video width or height if necessary to
6673 keep the original aspect ratio. Possible values:
6677 Scale the video as specified and disable this feature.
6680 The output video dimensions will automatically be decreased if needed.
6683 The output video dimensions will automatically be increased if needed.
6687 One useful instance of this option is that when you know a specific device's
6688 maximum allowed resolution, you can use this to limit the output video to
6689 that, while retaining the aspect ratio. For example, device A allows
6690 1280x720 playback, and your video is 1920x800. Using this option (set it to
6691 decrease) and specifying 1280x720 to the command line makes the output
6694 Please note that this is a different thing than specifying -1 for @option{w}
6695 or @option{h}, you still need to specify the output resolution for this option
6700 The values of the @option{w} and @option{h} options are expressions
6701 containing the following constants:
6706 the input width and height
6710 same as @var{in_w} and @var{in_h}
6714 the output (scaled) width and height
6718 same as @var{out_w} and @var{out_h}
6721 same as @var{iw} / @var{ih}
6724 input sample aspect ratio
6727 input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
6731 horizontal and vertical chroma subsample values. For example for the
6732 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6735 @subsection Examples
6739 Scale the input video to a size of 200x100:
6744 This is equivalent to:
6755 Specify a size abbreviation for the output size:
6760 which can also be written as:
6766 Scale the input to 2x:
6772 The above is the same as:
6778 Scale the input to 2x with forced interlaced scaling:
6780 scale=2*iw:2*ih:interl=1
6784 Scale the input to half size:
6790 Increase the width, and set the height to the same size:
6796 Seek for Greek harmony:
6803 Increase the height, and set the width to 3/2 of the height:
6805 scale=w=3/2*oh:h=3/5*ih
6809 Increase the size, but make the size a multiple of the chroma
6812 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
6816 Increase the width to a maximum of 500 pixels, keep the same input
6819 scale=w='min(500\, iw*3/2):h=-1'
6823 @section separatefields
6825 The @code{separatefields} takes a frame-based video input and splits
6826 each frame into its components fields, producing a new half height clip
6827 with twice the frame rate and twice the frame count.
6829 This filter use field-dominance information in frame to decide which
6830 of each pair of fields to place first in the output.
6831 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
6833 @section setdar, setsar
6835 The @code{setdar} filter sets the Display Aspect Ratio for the filter
6838 This is done by changing the specified Sample (aka Pixel) Aspect
6839 Ratio, according to the following equation:
6841 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
6844 Keep in mind that the @code{setdar} filter does not modify the pixel
6845 dimensions of the video frame. Also the display aspect ratio set by
6846 this filter may be changed by later filters in the filterchain,
6847 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
6850 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
6851 the filter output video.
6853 Note that as a consequence of the application of this filter, the
6854 output display aspect ratio will change according to the equation
6857 Keep in mind that the sample aspect ratio set by the @code{setsar}
6858 filter may be changed by later filters in the filterchain, e.g. if
6859 another "setsar" or a "setdar" filter is applied.
6861 The filters accept the following options:
6864 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
6865 Set the aspect ratio used by the filter.
6867 The parameter can be a floating point number string, an expression, or
6868 a string of the form @var{num}:@var{den}, where @var{num} and
6869 @var{den} are the numerator and denominator of the aspect ratio. If
6870 the parameter is not specified, it is assumed the value "0".
6871 In case the form "@var{num}:@var{den}" is used, the @code{:} character
6875 Set the maximum integer value to use for expressing numerator and
6876 denominator when reducing the expressed aspect ratio to a rational.
6877 Default value is @code{100}.
6881 @subsection Examples
6886 To change the display aspect ratio to 16:9, specify one of the following:
6894 To change the sample aspect ratio to 10:11, specify:
6900 To set a display aspect ratio of 16:9, and specify a maximum integer value of
6901 1000 in the aspect ratio reduction, use the command:
6903 setdar=ratio=16/9:max=1000
6911 Force field for the output video frame.
6913 The @code{setfield} filter marks the interlace type field for the
6914 output frames. It does not change the input frame, but only sets the
6915 corresponding property, which affects how the frame is treated by
6916 following filters (e.g. @code{fieldorder} or @code{yadif}).
6918 The filter accepts the following options:
6923 Available values are:
6927 Keep the same field property.
6930 Mark the frame as bottom-field-first.
6933 Mark the frame as top-field-first.
6936 Mark the frame as progressive.
6942 Show a line containing various information for each input video frame.
6943 The input video is not modified.
6945 The shown line contains a sequence of key/value pairs of the form
6946 @var{key}:@var{value}.
6948 A description of each shown parameter follows:
6952 sequential number of the input frame, starting from 0
6955 Presentation TimeStamp of the input frame, expressed as a number of
6956 time base units. The time base unit depends on the filter input pad.
6959 Presentation TimeStamp of the input frame, expressed as a number of
6963 position of the frame in the input stream, -1 if this information in
6964 unavailable and/or meaningless (for example in case of synthetic video)
6970 sample aspect ratio of the input frame, expressed in the form
6974 size of the input frame, expressed in the form
6975 @var{width}x@var{height}
6978 interlaced mode ("P" for "progressive", "T" for top field first, "B"
6979 for bottom field first)
6982 1 if the frame is a key frame, 0 otherwise
6985 picture type of the input frame ("I" for an I-frame, "P" for a
6986 P-frame, "B" for a B-frame, "?" for unknown type).
6987 Check also the documentation of the @code{AVPictureType} enum and of
6988 the @code{av_get_picture_type_char} function defined in
6989 @file{libavutil/avutil.h}.
6992 Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame
6994 @item plane_checksum
6995 Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
6996 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]"
7002 Blur the input video without impacting the outlines.
7004 The filter accepts the following options:
7007 @item luma_radius, lr
7008 Set the luma radius. The option value must be a float number in
7009 the range [0.1,5.0] that specifies the variance of the gaussian filter
7010 used to blur the image (slower if larger). Default value is 1.0.
7012 @item luma_strength, ls
7013 Set the luma strength. The option value must be a float number
7014 in the range [-1.0,1.0] that configures the blurring. A value included
7015 in [0.0,1.0] will blur the image whereas a value included in
7016 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7018 @item luma_threshold, lt
7019 Set the luma threshold used as a coefficient to determine
7020 whether a pixel should be blurred or not. The option value must be an
7021 integer in the range [-30,30]. A value of 0 will filter all the image,
7022 a value included in [0,30] will filter flat areas and a value included
7023 in [-30,0] will filter edges. Default value is 0.
7025 @item chroma_radius, cr
7026 Set the chroma radius. The option value must be a float number in
7027 the range [0.1,5.0] that specifies the variance of the gaussian filter
7028 used to blur the image (slower if larger). Default value is 1.0.
7030 @item chroma_strength, cs
7031 Set the chroma strength. The option value must be a float number
7032 in the range [-1.0,1.0] that configures the blurring. A value included
7033 in [0.0,1.0] will blur the image whereas a value included in
7034 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7036 @item chroma_threshold, ct
7037 Set the chroma threshold used as a coefficient to determine
7038 whether a pixel should be blurred or not. The option value must be an
7039 integer in the range [-30,30]. A value of 0 will filter all the image,
7040 a value included in [0,30] will filter flat areas and a value included
7041 in [-30,0] will filter edges. Default value is 0.
7044 If a chroma option is not explicitly set, the corresponding luma value
7049 Convert between different stereoscopic image formats.
7051 The filters accept the following options:
7055 Set stereoscopic image format of input.
7057 Available values for input image formats are:
7060 side by side parallel (left eye left, right eye right)
7063 side by side crosseye (right eye left, left eye right)
7066 side by side parallel with half width resolution
7067 (left eye left, right eye right)
7070 side by side crosseye with half width resolution
7071 (right eye left, left eye right)
7074 above-below (left eye above, right eye below)
7077 above-below (right eye above, left eye below)
7080 above-below with half height resolution
7081 (left eye above, right eye below)
7084 above-below with half height resolution
7085 (right eye above, left eye below)
7088 alternating frames (left eye first, right eye second)
7091 alternating frames (right eye first, left eye second)
7093 Default value is @samp{sbsl}.
7097 Set stereoscopic image format of output.
7099 Available values for output image formats are all the input formats as well as:
7102 anaglyph red/blue gray
7103 (red filter on left eye, blue filter on right eye)
7106 anaglyph red/green gray
7107 (red filter on left eye, green filter on right eye)
7110 anaglyph red/cyan gray
7111 (red filter on left eye, cyan filter on right eye)
7114 anaglyph red/cyan half colored
7115 (red filter on left eye, cyan filter on right eye)
7118 anaglyph red/cyan color
7119 (red filter on left eye, cyan filter on right eye)
7122 anaglyph red/cyan color optimized with the least squares projection of dubois
7123 (red filter on left eye, cyan filter on right eye)
7126 anaglyph green/magenta gray
7127 (green filter on left eye, magenta filter on right eye)
7130 anaglyph green/magenta half colored
7131 (green filter on left eye, magenta filter on right eye)
7134 anaglyph green/magenta colored
7135 (green filter on left eye, magenta filter on right eye)
7138 anaglyph green/magenta color optimized with the least squares projection of dubois
7139 (green filter on left eye, magenta filter on right eye)
7142 anaglyph yellow/blue gray
7143 (yellow filter on left eye, blue filter on right eye)
7146 anaglyph yellow/blue half colored
7147 (yellow filter on left eye, blue filter on right eye)
7150 anaglyph yellow/blue colored
7151 (yellow filter on left eye, blue filter on right eye)
7154 anaglyph yellow/blue color optimized with the least squares projection of dubois
7155 (yellow filter on left eye, blue filter on right eye)
7158 interleaved rows (left eye has top row, right eye starts on next row)
7161 interleaved rows (right eye has top row, left eye starts on next row)
7164 mono output (left eye only)
7167 mono output (right eye only)
7170 Default value is @samp{arcd}.
7173 @subsection Examples
7177 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
7183 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
7191 Apply a simple postprocessing filter that compresses and decompresses the image
7192 at several (or - in the case of @option{quality} level @code{6} - all) shifts
7193 and average the results.
7195 The filter accepts the following options:
7199 Set quality. This option defines the number of levels for averaging. It accepts
7200 an integer in the range 0-6. If set to @code{0}, the filter will have no
7201 effect. A value of @code{6} means the higher quality. For each increment of
7202 that value the speed drops by a factor of approximately 2. Default value is
7206 Force a constant quantization parameter. If not set, the filter will use the QP
7207 from the video stream (if available).
7210 Set thresholding mode. Available modes are:
7214 Set hard thresholding (default).
7216 Set soft thresholding (better de-ringing effect, but likely blurrier).
7220 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
7221 option may cause flicker since the B-Frames have often larger QP. Default is
7222 @code{0} (not enabled).
7228 Draw subtitles on top of input video using the libass library.
7230 To enable compilation of this filter you need to configure FFmpeg with
7231 @code{--enable-libass}. This filter also requires a build with libavcodec and
7232 libavformat to convert the passed subtitles file to ASS (Advanced Substation
7233 Alpha) subtitles format.
7235 The filter accepts the following options:
7239 Set the filename of the subtitle file to read. It must be specified.
7242 Specify the size of the original video, the video for which the ASS file
7243 was composed. Due to a misdesign in ASS aspect ratio arithmetic, this is
7244 necessary to correctly scale the fonts if the aspect ratio has been changed.
7247 Set subtitles input character encoding. @code{subtitles} filter only. Only
7248 useful if not UTF-8.
7251 If the first key is not specified, it is assumed that the first value
7252 specifies the @option{filename}.
7254 For example, to render the file @file{sub.srt} on top of the input
7255 video, use the command:
7260 which is equivalent to:
7262 subtitles=filename=sub.srt
7267 Scale the input by 2x and smooth using the Super2xSaI (Scale and
7268 Interpolate) pixel art scaling algorithm.
7270 Useful for enlarging pixel art images without reducing sharpness.
7277 Apply telecine process to the video.
7279 This filter accepts the following options:
7288 The default value is @code{top}.
7292 A string of numbers representing the pulldown pattern you wish to apply.
7293 The default value is @code{23}.
7297 Some typical patterns:
7302 24p: 2332 (preferred)
7309 24p: 222222222223 ("Euro pulldown")
7315 Select the most representative frame in a given sequence of consecutive frames.
7317 The filter accepts the following options:
7321 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
7322 will pick one of them, and then handle the next batch of @var{n} frames until
7323 the end. Default is @code{100}.
7326 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
7327 value will result in a higher memory usage, so a high value is not recommended.
7329 @subsection Examples
7333 Extract one picture each 50 frames:
7339 Complete example of a thumbnail creation with @command{ffmpeg}:
7341 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
7347 Tile several successive frames together.
7349 The filter accepts the following options:
7354 Set the grid size (i.e. the number of lines and columns) in the form
7358 Set the maximum number of frames to render in the given area. It must be less
7359 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
7360 the area will be used.
7363 Set the outer border margin in pixels.
7366 Set the inner border thickness (i.e. the number of pixels between frames). For
7367 more advanced padding options (such as having different values for the edges),
7368 refer to the pad video filter.
7371 Specify the color of the unused area, it can be the name of a color
7372 (case insensitive match) or a 0xRRGGBB[AA] sequence.
7373 The default value of @var{color} is "black".
7376 @subsection Examples
7380 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
7382 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
7384 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
7385 duplicating each output frame to accomodate the originally detected frame
7389 Display @code{5} pictures in an area of @code{3x2} frames,
7390 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
7391 mixed flat and named options:
7393 tile=3x2:nb_frames=5:padding=7:margin=2
7399 Perform various types of temporal field interlacing.
7401 Frames are counted starting from 1, so the first input frame is
7404 The filter accepts the following options:
7409 Specify the mode of the interlacing. This option can also be specified
7410 as a value alone. See below for a list of values for this option.
7412 Available values are:
7416 Move odd frames into the upper field, even into the lower field,
7417 generating a double height frame at half frame rate.
7420 Only output even frames, odd frames are dropped, generating a frame with
7421 unchanged height at half frame rate.
7424 Only output odd frames, even frames are dropped, generating a frame with
7425 unchanged height at half frame rate.
7428 Expand each frame to full height, but pad alternate lines with black,
7429 generating a frame with double height at the same input frame rate.
7431 @item interleave_top, 4
7432 Interleave the upper field from odd frames with the lower field from
7433 even frames, generating a frame with unchanged height at half frame rate.
7435 @item interleave_bottom, 5
7436 Interleave the lower field from odd frames with the upper field from
7437 even frames, generating a frame with unchanged height at half frame rate.
7439 @item interlacex2, 6
7440 Double frame rate with unchanged height. Frames are inserted each
7441 containing the second temporal field from the previous input frame and
7442 the first temporal field from the next input frame. This mode relies on
7443 the top_field_first flag. Useful for interlaced video displays with no
7444 field synchronisation.
7447 Numeric values are deprecated but are accepted for backward
7448 compatibility reasons.
7450 Default mode is @code{merge}.
7453 Specify flags influencing the filter process.
7455 Available value for @var{flags} is:
7458 @item low_pass_filter, vlfp
7459 Enable vertical low-pass filtering in the filter.
7460 Vertical low-pass filtering is required when creating an interlaced
7461 destination from a progressive source which contains high-frequency
7462 vertical detail. Filtering will reduce interlace 'twitter' and Moire
7465 Vertical low-pass filtering can only be enabled for @option{mode}
7466 @var{interleave_top} and @var{interleave_bottom}.
7473 Transpose rows with columns in the input video and optionally flip it.
7475 This filter accepts the following options:
7480 Specify the transposition direction.
7482 Can assume the following values:
7484 @item 0, 4, cclock_flip
7485 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
7493 Rotate by 90 degrees clockwise, that is:
7501 Rotate by 90 degrees counterclockwise, that is:
7508 @item 3, 7, clock_flip
7509 Rotate by 90 degrees clockwise and vertically flip, that is:
7517 For values between 4-7, the transposition is only done if the input
7518 video geometry is portrait and not landscape. These values are
7519 deprecated, the @code{passthrough} option should be used instead.
7521 Numerical values are deprecated, and should be dropped in favor of
7525 Do not apply the transposition if the input geometry matches the one
7526 specified by the specified value. It accepts the following values:
7529 Always apply transposition.
7531 Preserve portrait geometry (when @var{height} >= @var{width}).
7533 Preserve landscape geometry (when @var{width} >= @var{height}).
7536 Default value is @code{none}.
7539 For example to rotate by 90 degrees clockwise and preserve portrait
7542 transpose=dir=1:passthrough=portrait
7545 The command above can also be specified as:
7547 transpose=1:portrait
7551 Trim the input so that the output contains one continuous subpart of the input.
7553 This filter accepts the following options:
7556 Specify time of the start of the kept section, i.e. the frame with the
7557 timestamp @var{start} will be the first frame in the output.
7560 Specify time of the first frame that will be dropped, i.e. the frame
7561 immediately preceding the one with the timestamp @var{end} will be the last
7562 frame in the output.
7565 Same as @var{start}, except this option sets the start timestamp in timebase
7566 units instead of seconds.
7569 Same as @var{end}, except this option sets the end timestamp in timebase units
7573 Specify maximum duration of the output.
7576 Number of the first frame that should be passed to output.
7579 Number of the first frame that should be dropped.
7582 @option{start}, @option{end}, @option{duration} are expressed as time
7583 duration specifications, check the "Time duration" section in the
7584 ffmpeg-utils manual.
7586 Note that the first two sets of the start/end options and the @option{duration}
7587 option look at the frame timestamp, while the _frame variants simply count the
7588 frames that pass through the filter. Also note that this filter does not modify
7589 the timestamps. If you wish that the output timestamps start at zero, insert a
7590 setpts filter after the trim filter.
7592 If multiple start or end options are set, this filter tries to be greedy and
7593 keep all the frames that match at least one of the specified constraints. To keep
7594 only the part that matches all the constraints at once, chain multiple trim
7597 The defaults are such that all the input is kept. So it is possible to set e.g.
7598 just the end values to keep everything before the specified time.
7603 drop everything except the second minute of input
7605 ffmpeg -i INPUT -vf trim=60:120
7609 keep only the first second
7611 ffmpeg -i INPUT -vf trim=duration=1
7619 Sharpen or blur the input video.
7621 It accepts the following parameters:
7624 @item luma_msize_x, lx
7625 Set the luma matrix horizontal size. It must be an odd integer between
7626 3 and 63, default value is 5.
7628 @item luma_msize_y, ly
7629 Set the luma matrix vertical size. It must be an odd integer between 3
7630 and 63, default value is 5.
7632 @item luma_amount, la
7633 Set the luma effect strength. It can be a float number, reasonable
7634 values lay between -1.5 and 1.5.
7636 Negative values will blur the input video, while positive values will
7637 sharpen it, a value of zero will disable the effect.
7639 Default value is 1.0.
7641 @item chroma_msize_x, cx
7642 Set the chroma matrix horizontal size. It must be an odd integer
7643 between 3 and 63, default value is 5.
7645 @item chroma_msize_y, cy
7646 Set the chroma matrix vertical size. It must be an odd integer
7647 between 3 and 63, default value is 5.
7649 @item chroma_amount, ca
7650 Set the chroma effect strength. It can be a float number, reasonable
7651 values lay between -1.5 and 1.5.
7653 Negative values will blur the input video, while positive values will
7654 sharpen it, a value of zero will disable the effect.
7656 Default value is 0.0.
7659 If set to 1, specify using OpenCL capabilities, only available if
7660 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
7664 All parameters are optional and default to the equivalent of the
7665 string '5:5:1.0:5:5:0.0'.
7667 @subsection Examples
7671 Apply strong luma sharpen effect:
7673 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
7677 Apply strong blur of both luma and chroma parameters:
7679 unsharp=7:7:-2:7:7:-2
7683 @anchor{vidstabdetect}
7684 @section vidstabdetect
7686 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
7687 @ref{vidstabtransform} for pass 2.
7689 This filter generates a file with relative translation and rotation
7690 transform information about subsequent frames, which is then used by
7691 the @ref{vidstabtransform} filter.
7693 To enable compilation of this filter you need to configure FFmpeg with
7694 @code{--enable-libvidstab}.
7696 This filter accepts the following options:
7700 Set the path to the file used to write the transforms information.
7701 Default value is @file{transforms.trf}.
7704 Set how shaky the video is and how quick the camera is. It accepts an
7705 integer in the range 1-10, a value of 1 means little shakiness, a
7706 value of 10 means strong shakiness. Default value is 5.
7709 Set the accuracy of the detection process. It must be a value in the
7710 range 1-15. A value of 1 means low accuracy, a value of 15 means high
7711 accuracy. Default value is 9.
7714 Set stepsize of the search process. The region around minimum is
7715 scanned with 1 pixel resolution. Default value is 6.
7718 Set minimum contrast. Below this value a local measurement field is
7719 discarded. Must be a floating point value in the range 0-1. Default
7723 Set reference frame number for tripod mode.
7725 If enabled, the motion of the frames is compared to a reference frame
7726 in the filtered stream, identified by the specified number. The idea
7727 is to compensate all movements in a more-or-less static scene and keep
7728 the camera view absolutely still.
7730 If set to 0, it is disabled. The frames are counted starting from 1.
7733 Show fields and transforms in the resulting frames. It accepts an
7734 integer in the range 0-2. Default value is 0, which disables any
7738 @subsection Examples
7748 Analyze strongly shaky movie and put the results in file
7749 @file{mytransforms.trf}:
7751 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
7755 Visualize the result of internal transformations in the resulting
7758 vidstabdetect=show=1
7762 Analyze a video with medium shakiness using @command{ffmpeg}:
7764 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
7768 @anchor{vidstabtransform}
7769 @section vidstabtransform
7771 Video stabilization/deshaking: pass 2 of 2,
7772 see @ref{vidstabdetect} for pass 1.
7774 Read a file with transform information for each frame and
7775 apply/compensate them. Together with the @ref{vidstabdetect}
7776 filter this can be used to deshake videos. See also
7777 @url{http://public.hronopik.de/vid.stab}. It is important to also use
7778 the unsharp filter, see below.
7780 To enable compilation of this filter you need to configure FFmpeg with
7781 @code{--enable-libvidstab}.
7783 This filter accepts the following options:
7788 path to the file used to read the transforms (default: @file{transforms.trf})
7791 number of frames (value*2 + 1) used for lowpass filtering the camera movements
7792 (default: 10). For example a number of 10 means that 21 frames are used
7793 (10 in the past and 10 in the future) to smoothen the motion in the
7794 video. A larger values leads to a smoother video, but limits the
7795 acceleration of the camera (pan/tilt movements).
7798 maximal number of pixels to translate frames (default: -1 no limit)
7801 maximal angle in radians (degree*PI/180) to rotate frames (default: -1
7805 How to deal with borders that may be visible due to movement
7806 compensation. Available values are:
7810 keep image information from previous frame (default)
7812 fill the border black
7818 keep transforms normal (default)
7825 consider transforms as
7830 relative to previous frame (default)
7835 percentage to zoom (default: 0)
7844 if 1 then optimal zoom value is determined (default).
7845 Optimal zoom means no (or only little) border should be visible.
7846 Note that the value given at zoom is added to the one calculated
7850 type of interpolation
7852 Available values are:
7857 linear only horizontal
7859 linear in both directions (default)
7861 cubic in both directions (slow)
7865 virtual tripod mode means that the video is stabilized such that the
7866 camera stays stationary. Use also @code{tripod} option of
7867 @ref{vidstabdetect}.
7872 virtual tripod mode: equivalent to @code{relative=0:smoothing=0}
7877 @subsection Examples
7881 typical call with default default values:
7882 (note the unsharp filter which is always recommended)
7884 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
7888 zoom in a bit more and load transform data from a given file
7890 vidstabtransform=zoom=5:input="mytransforms.trf"
7894 smoothen the video even more
7896 vidstabtransform=smoothing=30
7903 Flip the input video vertically.
7905 For example, to vertically flip a video with @command{ffmpeg}:
7907 ffmpeg -i in.avi -vf "vflip" out.avi
7912 Make or reverse a natural vignetting effect.
7914 The filter accepts the following options:
7918 Set lens angle expression as a number of radians.
7920 The value is clipped in the @code{[0,PI/2]} range.
7922 Default value: @code{"PI/5"}
7926 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
7930 Set forward/backward mode.
7932 Available modes are:
7935 The larger the distance from the central point, the darker the image becomes.
7938 The larger the distance from the central point, the brighter the image becomes.
7939 This can be used to reverse a vignette effect, though there is no automatic
7940 detection to extract the lens @option{angle} and other settings (yet). It can
7941 also be used to create a burning effect.
7944 Default value is @samp{forward}.
7947 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
7949 It accepts the following values:
7952 Evaluate expressions only once during the filter initialization.
7955 Evaluate expressions for each incoming frame. This is way slower than the
7956 @samp{init} mode since it requires all the scalers to be re-computed, but it
7957 allows advanced dynamic expressions.
7960 Default value is @samp{init}.
7963 Set dithering to reduce the circular banding effects. Default is @code{1}
7967 Set vignette aspect. This setting allows to adjust the shape of the vignette.
7968 Setting this value to the SAR of the input will make a rectangular vignetting
7969 following the dimensions of the video.
7971 Default is @code{1/1}.
7974 @subsection Expressions
7976 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
7977 following parameters.
7982 input width and height
7985 the number of input frame, starting from 0
7988 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
7989 @var{TB} units, NAN if undefined
7992 frame rate of the input video, NAN if the input frame rate is unknown
7995 the PTS (Presentation TimeStamp) of the filtered video frame,
7996 expressed in seconds, NAN if undefined
7999 time base of the input video
8003 @subsection Examples
8007 Apply simple strong vignetting effect:
8013 Make a flickering vignetting:
8015 vignette='PI/4+random(1)*PI/50':eval=frame
8022 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
8023 Deinterlacing Filter").
8025 Based on the process described by Martin Weston for BBC R&D, and
8026 implemented based on the de-interlace algorithm written by Jim
8027 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
8028 uses filter coefficients calculated by BBC R&D.
8030 There are two sets of filter coefficients, so called "simple":
8031 and "complex". Which set of filter coefficients is used can
8032 be set by passing an optional parameter:
8036 Set the interlacing filter coefficients. Accepts one of the following values:
8040 Simple filter coefficient set.
8042 More-complex filter coefficient set.
8044 Default value is @samp{complex}.
8047 Specify which frames to deinterlace. Accept one of the following values:
8051 Deinterlace all frames,
8053 Only deinterlace frames marked as interlaced.
8056 Default value is @samp{all}.
8062 Deinterlace the input video ("yadif" means "yet another deinterlacing
8065 This filter accepts the following options:
8071 The interlacing mode to adopt, accepts one of the following values:
8075 output 1 frame for each frame
8077 output 1 frame for each field
8078 @item 2, send_frame_nospatial
8079 like @code{send_frame} but skip spatial interlacing check
8080 @item 3, send_field_nospatial
8081 like @code{send_field} but skip spatial interlacing check
8084 Default value is @code{send_frame}.
8087 The picture field parity assumed for the input interlaced video, accepts one of
8088 the following values:
8092 assume top field first
8094 assume bottom field first
8096 enable automatic detection
8099 Default value is @code{auto}.
8100 If interlacing is unknown or decoder does not export this information,
8101 top field first will be assumed.
8104 Specify which frames to deinterlace. Accept one of the following
8109 deinterlace all frames
8111 only deinterlace frames marked as interlaced
8114 Default value is @code{all}.
8117 @c man end VIDEO FILTERS
8119 @chapter Video Sources
8120 @c man begin VIDEO SOURCES
8122 Below is a description of the currently available video sources.
8126 Buffer video frames, and make them available to the filter chain.
8128 This source is mainly intended for a programmatic use, in particular
8129 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
8131 This source accepts the following options:
8136 Specify the size (width and height) of the buffered video frames.
8145 A string representing the pixel format of the buffered video frames.
8146 It may be a number corresponding to a pixel format, or a pixel format
8150 Specify the timebase assumed by the timestamps of the buffered frames.
8153 Specify the frame rate expected for the video stream.
8155 @item pixel_aspect, sar
8156 Specify the sample aspect ratio assumed by the video frames.
8159 Specify the optional parameters to be used for the scale filter which
8160 is automatically inserted when an input change is detected in the
8161 input size or format.
8166 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
8169 will instruct the source to accept video frames with size 320x240 and
8170 with format "yuv410p", assuming 1/24 as the timestamps timebase and
8171 square pixels (1:1 sample aspect ratio).
8172 Since the pixel format with name "yuv410p" corresponds to the number 6
8173 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
8174 this example corresponds to:
8176 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
8179 Alternatively, the options can be specified as a flat string, but this
8180 syntax is deprecated:
8182 @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}]
8186 Create a pattern generated by an elementary cellular automaton.
8188 The initial state of the cellular automaton can be defined through the
8189 @option{filename}, and @option{pattern} options. If such options are
8190 not specified an initial state is created randomly.
8192 At each new frame a new row in the video is filled with the result of
8193 the cellular automaton next generation. The behavior when the whole
8194 frame is filled is defined by the @option{scroll} option.
8196 This source accepts the following options:
8200 Read the initial cellular automaton state, i.e. the starting row, from
8202 In the file, each non-whitespace character is considered an alive
8203 cell, a newline will terminate the row, and further characters in the
8204 file will be ignored.
8207 Read the initial cellular automaton state, i.e. the starting row, from
8208 the specified string.
8210 Each non-whitespace character in the string is considered an alive
8211 cell, a newline will terminate the row, and further characters in the
8212 string will be ignored.
8215 Set the video rate, that is the number of frames generated per second.
8218 @item random_fill_ratio, ratio
8219 Set the random fill ratio for the initial cellular automaton row. It
8220 is a floating point number value ranging from 0 to 1, defaults to
8223 This option is ignored when a file or a pattern is specified.
8225 @item random_seed, seed
8226 Set the seed for filling randomly the initial row, must be an integer
8227 included between 0 and UINT32_MAX. If not specified, or if explicitly
8228 set to -1, the filter will try to use a good random seed on a best
8232 Set the cellular automaton rule, it is a number ranging from 0 to 255.
8233 Default value is 110.
8236 Set the size of the output video.
8238 If @option{filename} or @option{pattern} is specified, the size is set
8239 by default to the width of the specified initial state row, and the
8240 height is set to @var{width} * PHI.
8242 If @option{size} is set, it must contain the width of the specified
8243 pattern string, and the specified pattern will be centered in the
8246 If a filename or a pattern string is not specified, the size value
8247 defaults to "320x518" (used for a randomly generated initial state).
8250 If set to 1, scroll the output upward when all the rows in the output
8251 have been already filled. If set to 0, the new generated row will be
8252 written over the top row just after the bottom row is filled.
8255 @item start_full, full
8256 If set to 1, completely fill the output with generated rows before
8257 outputting the first frame.
8258 This is the default behavior, for disabling set the value to 0.
8261 If set to 1, stitch the left and right row edges together.
8262 This is the default behavior, for disabling set the value to 0.
8265 @subsection Examples
8269 Read the initial state from @file{pattern}, and specify an output of
8272 cellauto=f=pattern:s=200x400
8276 Generate a random initial row with a width of 200 cells, with a fill
8279 cellauto=ratio=2/3:s=200x200
8283 Create a pattern generated by rule 18 starting by a single alive cell
8284 centered on an initial row with width 100:
8286 cellauto=p=@@:s=100x400:full=0:rule=18
8290 Specify a more elaborated initial pattern:
8292 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
8299 Generate a Mandelbrot set fractal, and progressively zoom towards the
8300 point specified with @var{start_x} and @var{start_y}.
8302 This source accepts the following options:
8307 Set the terminal pts value. Default value is 400.
8310 Set the terminal scale value.
8311 Must be a floating point value. Default value is 0.3.
8314 Set the inner coloring mode, that is the algorithm used to draw the
8315 Mandelbrot fractal internal region.
8317 It shall assume one of the following values:
8322 Show time until convergence.
8324 Set color based on point closest to the origin of the iterations.
8329 Default value is @var{mincol}.
8332 Set the bailout value. Default value is 10.0.
8335 Set the maximum of iterations performed by the rendering
8336 algorithm. Default value is 7189.
8339 Set outer coloring mode.
8340 It shall assume one of following values:
8342 @item iteration_count
8343 Set iteration cound mode.
8344 @item normalized_iteration_count
8345 set normalized iteration count mode.
8347 Default value is @var{normalized_iteration_count}.
8350 Set frame rate, expressed as number of frames per second. Default
8354 Set frame size. Default value is "640x480".
8357 Set the initial scale value. Default value is 3.0.
8360 Set the initial x position. Must be a floating point value between
8361 -100 and 100. Default value is -0.743643887037158704752191506114774.
8364 Set the initial y position. Must be a floating point value between
8365 -100 and 100. Default value is -0.131825904205311970493132056385139.
8370 Generate various test patterns, as generated by the MPlayer test filter.
8372 The size of the generated video is fixed, and is 256x256.
8373 This source is useful in particular for testing encoding features.
8375 This source accepts the following options:
8380 Specify the frame rate of the sourced video, as the number of frames
8381 generated per second. It has to be a string in the format
8382 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
8383 number or a valid video frame rate abbreviation. The default value is
8387 Set the video duration of the sourced video. The accepted syntax is:
8392 See also the function @code{av_parse_time()}.
8394 If not specified, or the expressed duration is negative, the video is
8395 supposed to be generated forever.
8399 Set the number or the name of the test to perform. Supported tests are:
8414 Default value is "all", which will cycle through the list of all tests.
8417 For example the following:
8422 will generate a "dc_luma" test pattern.
8426 Provide a frei0r source.
8428 To enable compilation of this filter you need to install the frei0r
8429 header and configure FFmpeg with @code{--enable-frei0r}.
8431 This source accepts the following options:
8436 The size of the video to generate, may be a string of the form
8437 @var{width}x@var{height} or a frame size abbreviation.
8440 Framerate of the generated video, may be a string of the form
8441 @var{num}/@var{den} or a frame rate abbreviation.
8444 The name to the frei0r source to load. For more information regarding frei0r and
8445 how to set the parameters read the section @ref{frei0r} in the description of
8449 A '|'-separated list of parameters to pass to the frei0r source.
8453 For example, to generate a frei0r partik0l source with size 200x200
8454 and frame rate 10 which is overlayed on the overlay filter main input:
8456 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
8461 Generate a life pattern.
8463 This source is based on a generalization of John Conway's life game.
8465 The sourced input represents a life grid, each pixel represents a cell
8466 which can be in one of two possible states, alive or dead. Every cell
8467 interacts with its eight neighbours, which are the cells that are
8468 horizontally, vertically, or diagonally adjacent.
8470 At each interaction the grid evolves according to the adopted rule,
8471 which specifies the number of neighbor alive cells which will make a
8472 cell stay alive or born. The @option{rule} option allows to specify
8475 This source accepts the following options:
8479 Set the file from which to read the initial grid state. In the file,
8480 each non-whitespace character is considered an alive cell, and newline
8481 is used to delimit the end of each row.
8483 If this option is not specified, the initial grid is generated
8487 Set the video rate, that is the number of frames generated per second.
8490 @item random_fill_ratio, ratio
8491 Set the random fill ratio for the initial random grid. It is a
8492 floating point number value ranging from 0 to 1, defaults to 1/PHI.
8493 It is ignored when a file is specified.
8495 @item random_seed, seed
8496 Set the seed for filling the initial random grid, must be an integer
8497 included between 0 and UINT32_MAX. If not specified, or if explicitly
8498 set to -1, the filter will try to use a good random seed on a best
8504 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
8505 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
8506 @var{NS} specifies the number of alive neighbor cells which make a
8507 live cell stay alive, and @var{NB} the number of alive neighbor cells
8508 which make a dead cell to become alive (i.e. to "born").
8509 "s" and "b" can be used in place of "S" and "B", respectively.
8511 Alternatively a rule can be specified by an 18-bits integer. The 9
8512 high order bits are used to encode the next cell state if it is alive
8513 for each number of neighbor alive cells, the low order bits specify
8514 the rule for "borning" new cells. Higher order bits encode for an
8515 higher number of neighbor cells.
8516 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
8517 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
8519 Default value is "S23/B3", which is the original Conway's game of life
8520 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
8521 cells, and will born a new cell if there are three alive cells around
8525 Set the size of the output video.
8527 If @option{filename} is specified, the size is set by default to the
8528 same size of the input file. If @option{size} is set, it must contain
8529 the size specified in the input file, and the initial grid defined in
8530 that file is centered in the larger resulting area.
8532 If a filename is not specified, the size value defaults to "320x240"
8533 (used for a randomly generated initial grid).
8536 If set to 1, stitch the left and right grid edges together, and the
8537 top and bottom edges also. Defaults to 1.
8540 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
8541 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
8542 value from 0 to 255.
8545 Set the color of living (or new born) cells.
8548 Set the color of dead cells. If @option{mold} is set, this is the first color
8549 used to represent a dead cell.
8552 Set mold color, for definitely dead and moldy cells.
8555 @subsection Examples
8559 Read a grid from @file{pattern}, and center it on a grid of size
8562 life=f=pattern:s=300x300
8566 Generate a random grid of size 200x200, with a fill ratio of 2/3:
8568 life=ratio=2/3:s=200x200
8572 Specify a custom rule for evolving a randomly generated grid:
8578 Full example with slow death effect (mold) using @command{ffplay}:
8580 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
8585 @anchor{haldclutsrc}
8589 @anchor{smptehdbars}
8591 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
8593 The @code{color} source provides an uniformly colored input.
8595 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
8596 @ref{haldclut} filter.
8598 The @code{nullsrc} source returns unprocessed video frames. It is
8599 mainly useful to be employed in analysis / debugging tools, or as the
8600 source for filters which ignore the input data.
8602 The @code{rgbtestsrc} source generates an RGB test pattern useful for
8603 detecting RGB vs BGR issues. You should see a red, green and blue
8604 stripe from top to bottom.
8606 The @code{smptebars} source generates a color bars pattern, based on
8607 the SMPTE Engineering Guideline EG 1-1990.
8609 The @code{smptehdbars} source generates a color bars pattern, based on
8610 the SMPTE RP 219-2002.
8612 The @code{testsrc} source generates a test video pattern, showing a
8613 color pattern, a scrolling gradient and a timestamp. This is mainly
8614 intended for testing purposes.
8616 The sources accept the following options:
8621 Specify the color of the source, only available in the @code{color}
8622 source. It can be the name of a color (case insensitive match) or a
8623 0xRRGGBB[AA] sequence, possibly followed by an alpha specifier. The
8624 default value is "black".
8627 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
8628 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
8629 pixels to be used as identity matrix for 3D lookup tables. Each component is
8630 coded on a @code{1/(N*N)} scale.
8633 Specify the size of the sourced video, it may be a string of the form
8634 @var{width}x@var{height}, or the name of a size abbreviation. The
8635 default value is "320x240".
8637 This option is not available with the @code{haldclutsrc} filter.
8640 Specify the frame rate of the sourced video, as the number of frames
8641 generated per second. It has to be a string in the format
8642 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
8643 number or a valid video frame rate abbreviation. The default value is
8647 Set the sample aspect ratio of the sourced video.
8650 Set the video duration of the sourced video. The accepted syntax is:
8652 [-]HH[:MM[:SS[.m...]]]
8655 See also the function @code{av_parse_time()}.
8657 If not specified, or the expressed duration is negative, the video is
8658 supposed to be generated forever.
8661 Set the number of decimals to show in the timestamp, only available in the
8662 @code{testsrc} source.
8664 The displayed timestamp value will correspond to the original
8665 timestamp value multiplied by the power of 10 of the specified
8666 value. Default value is 0.
8669 For example the following:
8671 testsrc=duration=5.3:size=qcif:rate=10
8674 will generate a video with a duration of 5.3 seconds, with size
8675 176x144 and a frame rate of 10 frames per second.
8677 The following graph description will generate a red source
8678 with an opacity of 0.2, with size "qcif" and a frame rate of 10
8681 color=c=red@@0.2:s=qcif:r=10
8684 If the input content is to be ignored, @code{nullsrc} can be used. The
8685 following command generates noise in the luminance plane by employing
8686 the @code{geq} filter:
8688 nullsrc=s=256x256, geq=random(1)*255:128:128
8691 @subsection Commands
8693 The @code{color} source supports the following commands:
8697 Set the color of the created image. Accepts the same syntax of the
8698 corresponding @option{color} option.
8701 @c man end VIDEO SOURCES
8703 @chapter Video Sinks
8704 @c man begin VIDEO SINKS
8706 Below is a description of the currently available video sinks.
8710 Buffer video frames, and make them available to the end of the filter
8713 This sink is mainly intended for a programmatic use, in particular
8714 through the interface defined in @file{libavfilter/buffersink.h}
8715 or the options system.
8717 It accepts a pointer to an AVBufferSinkContext structure, which
8718 defines the incoming buffers' formats, to be passed as the opaque
8719 parameter to @code{avfilter_init_filter} for initialization.
8723 Null video sink, do absolutely nothing with the input video. It is
8724 mainly useful as a template and to be employed in analysis / debugging
8727 @c man end VIDEO SINKS
8729 @chapter Multimedia Filters
8730 @c man begin MULTIMEDIA FILTERS
8732 Below is a description of the currently available multimedia filters.
8734 @section avectorscope
8736 Convert input audio to a video output, representing the audio vector
8739 The filter is used to measure the difference between channels of stereo
8740 audio stream. A monoaural signal, consisting of identical left and right
8741 signal, results in straight vertical line. Any stereo separation is visible
8742 as a deviation from this line, creating a Lissajous figure.
8743 If the straight (or deviation from it) but horizontal line appears this
8744 indicates that the left and right channels are out of phase.
8746 The filter accepts the following options:
8750 Set the vectorscope mode.
8752 Available values are:
8755 Lissajous rotated by 45 degrees.
8758 Same as above but not rotated.
8761 Default value is @samp{lissajous}.
8764 Set the video size for the output. Default value is @code{400x400}.
8767 Set the output frame rate. Default value is @code{25}.
8772 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
8773 Allowed range is @code{[0, 255]}.
8778 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
8779 Allowed range is @code{[0, 255]}.
8782 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
8785 @subsection Examples
8789 Complete example using @command{ffplay}:
8791 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
8792 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
8798 Concatenate audio and video streams, joining them together one after the
8801 The filter works on segments of synchronized video and audio streams. All
8802 segments must have the same number of streams of each type, and that will
8803 also be the number of streams at output.
8805 The filter accepts the following options:
8810 Set the number of segments. Default is 2.
8813 Set the number of output video streams, that is also the number of video
8814 streams in each segment. Default is 1.
8817 Set the number of output audio streams, that is also the number of video
8818 streams in each segment. Default is 0.
8821 Activate unsafe mode: do not fail if segments have a different format.
8825 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
8826 @var{a} audio outputs.
8828 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
8829 segment, in the same order as the outputs, then the inputs for the second
8832 Related streams do not always have exactly the same duration, for various
8833 reasons including codec frame size or sloppy authoring. For that reason,
8834 related synchronized streams (e.g. a video and its audio track) should be
8835 concatenated at once. The concat filter will use the duration of the longest
8836 stream in each segment (except the last one), and if necessary pad shorter
8837 audio streams with silence.
8839 For this filter to work correctly, all segments must start at timestamp 0.
8841 All corresponding streams must have the same parameters in all segments; the
8842 filtering system will automatically select a common pixel format for video
8843 streams, and a common sample format, sample rate and channel layout for
8844 audio streams, but other settings, such as resolution, must be converted
8845 explicitly by the user.
8847 Different frame rates are acceptable but will result in variable frame rate
8848 at output; be sure to configure the output file to handle it.
8850 @subsection Examples
8854 Concatenate an opening, an episode and an ending, all in bilingual version
8855 (video in stream 0, audio in streams 1 and 2):
8857 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
8858 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
8859 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
8860 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
8864 Concatenate two parts, handling audio and video separately, using the
8865 (a)movie sources, and adjusting the resolution:
8867 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
8868 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
8869 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
8871 Note that a desync will happen at the stitch if the audio and video streams
8872 do not have exactly the same duration in the first file.
8878 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
8879 it unchanged. By default, it logs a message at a frequency of 10Hz with the
8880 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
8881 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
8883 The filter also has a video output (see the @var{video} option) with a real
8884 time graph to observe the loudness evolution. The graphic contains the logged
8885 message mentioned above, so it is not printed anymore when this option is set,
8886 unless the verbose logging is set. The main graphing area contains the
8887 short-term loudness (3 seconds of analysis), and the gauge on the right is for
8888 the momentary loudness (400 milliseconds).
8890 More information about the Loudness Recommendation EBU R128 on
8891 @url{http://tech.ebu.ch/loudness}.
8893 The filter accepts the following options:
8898 Activate the video output. The audio stream is passed unchanged whether this
8899 option is set or no. The video stream will be the first output stream if
8900 activated. Default is @code{0}.
8903 Set the video size. This option is for video only. Default and minimum
8904 resolution is @code{640x480}.
8907 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
8908 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
8909 other integer value between this range is allowed.
8912 Set metadata injection. If set to @code{1}, the audio input will be segmented
8913 into 100ms output frames, each of them containing various loudness information
8914 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
8916 Default is @code{0}.
8919 Force the frame logging level.
8921 Available values are:
8924 information logging level
8926 verbose logging level
8929 By default, the logging level is set to @var{info}. If the @option{video} or
8930 the @option{metadata} options are set, it switches to @var{verbose}.
8933 @subsection Examples
8937 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
8939 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
8943 Run an analysis with @command{ffmpeg}:
8945 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
8949 @section interleave, ainterleave
8951 Temporally interleave frames from several inputs.
8953 @code{interleave} works with video inputs, @code{ainterleave} with audio.
8955 These filters read frames from several inputs and send the oldest
8956 queued frame to the output.
8958 Input streams must have a well defined, monotonically increasing frame
8961 In order to submit one frame to output, these filters need to enqueue
8962 at least one frame for each input, so they cannot work in case one
8963 input is not yet terminated and will not receive incoming frames.
8965 For example consider the case when one input is a @code{select} filter
8966 which always drop input frames. The @code{interleave} filter will keep
8967 reading from that input, but it will never be able to send new frames
8968 to output until the input will send an end-of-stream signal.
8970 Also, depending on inputs synchronization, the filters will drop
8971 frames in case one input receives more frames than the other ones, and
8972 the queue is already filled.
8974 These filters accept the following options:
8978 Set the number of different inputs, it is 2 by default.
8981 @subsection Examples
8985 Interleave frames belonging to different streams using @command{ffmpeg}:
8987 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
8991 Add flickering blur effect:
8993 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
8997 @section perms, aperms
8999 Set read/write permissions for the output frames.
9001 These filters are mainly aimed at developers to test direct path in the
9002 following filter in the filtergraph.
9004 The filters accept the following options:
9008 Select the permissions mode.
9010 It accepts the following values:
9013 Do nothing. This is the default.
9015 Set all the output frames read-only.
9017 Set all the output frames directly writable.
9019 Make the frame read-only if writable, and writable if read-only.
9021 Set each output frame read-only or writable randomly.
9025 Set the seed for the @var{random} mode, must be an integer included between
9026 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
9027 @code{-1}, the filter will try to use a good random seed on a best effort
9031 Note: in case of auto-inserted filter between the permission filter and the
9032 following one, the permission might not be received as expected in that
9033 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
9034 perms/aperms filter can avoid this problem.
9036 @section select, aselect
9038 Select frames to pass in output.
9040 This filter accepts the following options:
9045 Set expression, which is evaluated for each input frame.
9047 If the expression is evaluated to zero, the frame is discarded.
9049 If the evaluation result is negative or NaN, the frame is sent to the
9050 first output; otherwise it is sent to the output with index
9051 @code{ceil(val)-1}, assuming that the input index starts from 0.
9053 For example a value of @code{1.2} corresponds to the output with index
9054 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
9057 Set the number of outputs. The output to which to send the selected
9058 frame is based on the result of the evaluation. Default value is 1.
9061 The expression can contain the following constants:
9065 the sequential number of the filtered frame, starting from 0
9068 the sequential number of the selected frame, starting from 0
9070 @item prev_selected_n
9071 the sequential number of the last selected frame, NAN if undefined
9074 timebase of the input timestamps
9077 the PTS (Presentation TimeStamp) of the filtered video frame,
9078 expressed in @var{TB} units, NAN if undefined
9081 the PTS (Presentation TimeStamp) of the filtered video frame,
9082 expressed in seconds, NAN if undefined
9085 the PTS of the previously filtered video frame, NAN if undefined
9087 @item prev_selected_pts
9088 the PTS of the last previously filtered video frame, NAN if undefined
9090 @item prev_selected_t
9091 the PTS of the last previously selected video frame, NAN if undefined
9094 the PTS of the first video frame in the video, NAN if undefined
9097 the time of the first video frame in the video, NAN if undefined
9099 @item pict_type @emph{(video only)}
9100 the type of the filtered frame, can assume one of the following
9112 @item interlace_type @emph{(video only)}
9113 the frame interlace type, can assume one of the following values:
9116 the frame is progressive (not interlaced)
9118 the frame is top-field-first
9120 the frame is bottom-field-first
9123 @item consumed_sample_n @emph{(audio only)}
9124 the number of selected samples before the current frame
9126 @item samples_n @emph{(audio only)}
9127 the number of samples in the current frame
9129 @item sample_rate @emph{(audio only)}
9130 the input sample rate
9133 1 if the filtered frame is a key-frame, 0 otherwise
9136 the position in the file of the filtered frame, -1 if the information
9137 is not available (e.g. for synthetic video)
9139 @item scene @emph{(video only)}
9140 value between 0 and 1 to indicate a new scene; a low value reflects a low
9141 probability for the current frame to introduce a new scene, while a higher
9142 value means the current frame is more likely to be one (see the example below)
9146 The default value of the select expression is "1".
9148 @subsection Examples
9152 Select all frames in input:
9157 The example above is the same as:
9169 Select only I-frames:
9171 select='eq(pict_type\,I)'
9175 Select one frame every 100:
9177 select='not(mod(n\,100))'
9181 Select only frames contained in the 10-20 time interval:
9183 select='gte(t\,10)*lte(t\,20)'
9187 Select only I frames contained in the 10-20 time interval:
9189 select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
9193 Select frames with a minimum distance of 10 seconds:
9195 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
9199 Use aselect to select only audio frames with samples number > 100:
9201 aselect='gt(samples_n\,100)'
9205 Create a mosaic of the first scenes:
9207 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
9210 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
9214 Send even and odd frames to separate outputs, and compose them:
9216 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
9220 @section sendcmd, asendcmd
9222 Send commands to filters in the filtergraph.
9224 These filters read commands to be sent to other filters in the
9227 @code{sendcmd} must be inserted between two video filters,
9228 @code{asendcmd} must be inserted between two audio filters, but apart
9229 from that they act the same way.
9231 The specification of commands can be provided in the filter arguments
9232 with the @var{commands} option, or in a file specified by the
9233 @var{filename} option.
9235 These filters accept the following options:
9238 Set the commands to be read and sent to the other filters.
9240 Set the filename of the commands to be read and sent to the other
9244 @subsection Commands syntax
9246 A commands description consists of a sequence of interval
9247 specifications, comprising a list of commands to be executed when a
9248 particular event related to that interval occurs. The occurring event
9249 is typically the current frame time entering or leaving a given time
9252 An interval is specified by the following syntax:
9254 @var{START}[-@var{END}] @var{COMMANDS};
9257 The time interval is specified by the @var{START} and @var{END} times.
9258 @var{END} is optional and defaults to the maximum time.
9260 The current frame time is considered within the specified interval if
9261 it is included in the interval [@var{START}, @var{END}), that is when
9262 the time is greater or equal to @var{START} and is lesser than
9265 @var{COMMANDS} consists of a sequence of one or more command
9266 specifications, separated by ",", relating to that interval. The
9267 syntax of a command specification is given by:
9269 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
9272 @var{FLAGS} is optional and specifies the type of events relating to
9273 the time interval which enable sending the specified command, and must
9274 be a non-null sequence of identifier flags separated by "+" or "|" and
9275 enclosed between "[" and "]".
9277 The following flags are recognized:
9280 The command is sent when the current frame timestamp enters the
9281 specified interval. In other words, the command is sent when the
9282 previous frame timestamp was not in the given interval, and the
9286 The command is sent when the current frame timestamp leaves the
9287 specified interval. In other words, the command is sent when the
9288 previous frame timestamp was in the given interval, and the
9292 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
9295 @var{TARGET} specifies the target of the command, usually the name of
9296 the filter class or a specific filter instance name.
9298 @var{COMMAND} specifies the name of the command for the target filter.
9300 @var{ARG} is optional and specifies the optional list of argument for
9301 the given @var{COMMAND}.
9303 Between one interval specification and another, whitespaces, or
9304 sequences of characters starting with @code{#} until the end of line,
9305 are ignored and can be used to annotate comments.
9307 A simplified BNF description of the commands specification syntax
9310 @var{COMMAND_FLAG} ::= "enter" | "leave"
9311 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
9312 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
9313 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
9314 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
9315 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
9318 @subsection Examples
9322 Specify audio tempo change at second 4:
9324 asendcmd=c='4.0 atempo tempo 1.5',atempo
9328 Specify a list of drawtext and hue commands in a file.
9330 # show text in the interval 5-10
9331 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
9332 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
9334 # desaturate the image in the interval 15-20
9335 15.0-20.0 [enter] hue s 0,
9336 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
9338 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
9340 # apply an exponential saturation fade-out effect, starting from time 25
9341 25 [enter] hue s exp(25-t)
9344 A filtergraph allowing to read and process the above command list
9345 stored in a file @file{test.cmd}, can be specified with:
9347 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
9352 @section setpts, asetpts
9354 Change the PTS (presentation timestamp) of the input frames.
9356 @code{setpts} works on video frames, @code{asetpts} on audio frames.
9358 This filter accepts the following options:
9363 The expression which is evaluated for each frame to construct its timestamp.
9367 The expression is evaluated through the eval API and can contain the following
9372 frame rate, only defined for constant frame-rate video
9375 the presentation timestamp in input
9378 the count of the input frame for video or the number of consumed samples,
9379 not including the current frame for audio, starting from 0.
9381 @item NB_CONSUMED_SAMPLES
9382 the number of consumed samples, not including the current frame (only
9386 the number of samples in the current frame (only audio)
9388 @item SAMPLE_RATE, SR
9392 the PTS of the first frame
9395 the time in seconds of the first frame
9398 tell if the current frame is interlaced
9401 the time in seconds of the current frame
9404 original position in the file of the frame, or undefined if undefined
9405 for the current frame
9411 previous input time in seconds
9417 previous output time in seconds
9420 wallclock (RTC) time in microseconds. This is deprecated, use time(0)
9424 wallclock (RTC) time at the start of the movie in microseconds
9427 timebase of the input timestamps
9431 @subsection Examples
9435 Start counting PTS from zero
9441 Apply fast motion effect:
9447 Apply slow motion effect:
9453 Set fixed rate of 25 frames per second:
9459 Set fixed rate 25 fps with some jitter:
9461 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
9465 Apply an offset of 10 seconds to the input PTS:
9471 Generate timestamps from a "live source" and rebase onto the current timebase:
9473 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
9477 Generate timestamps by counting samples:
9484 @section settb, asettb
9486 Set the timebase to use for the output frames timestamps.
9487 It is mainly useful for testing timebase configuration.
9489 This filter accepts the following options:
9494 The expression which is evaluated into the output timebase.
9498 The value for @option{tb} is an arithmetic expression representing a
9499 rational. The expression can contain the constants "AVTB" (the default
9500 timebase), "intb" (the input timebase) and "sr" (the sample rate,
9501 audio only). Default value is "intb".
9503 @subsection Examples
9507 Set the timebase to 1/25:
9513 Set the timebase to 1/10:
9519 Set the timebase to 1001/1000:
9525 Set the timebase to 2*intb:
9531 Set the default timebase value:
9537 @section showspectrum
9539 Convert input audio to a video output, representing the audio frequency
9542 The filter accepts the following options:
9546 Specify the video size for the output. Default value is @code{640x512}.
9549 Specify if the spectrum should slide along the window. Default value is
9553 Specify display mode.
9555 It accepts the following values:
9558 all channels are displayed in the same row
9560 all channels are displayed in separate rows
9563 Default value is @samp{combined}.
9566 Specify display color mode.
9568 It accepts the following values:
9571 each channel is displayed in a separate color
9573 each channel is is displayed using the same color scheme
9576 Default value is @samp{channel}.
9579 Specify scale used for calculating intensity color values.
9581 It accepts the following values:
9586 square root, default
9593 Default value is @samp{sqrt}.
9596 Set saturation modifier for displayed colors. Negative values provide
9597 alternative color scheme. @code{0} is no saturation at all.
9598 Saturation must be in [-10.0, 10.0] range.
9599 Default value is @code{1}.
9602 The usage is very similar to the showwaves filter; see the examples in that
9605 @subsection Examples
9609 Large window with logarithmic color scaling:
9611 showspectrum=s=1280x480:scale=log
9615 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
9617 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9618 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
9624 Convert input audio to a video output, representing the samples waves.
9626 The filter accepts the following options:
9630 Specify the video size for the output. Default value is "600x240".
9635 Available values are:
9638 Draw a point for each sample.
9641 Draw a vertical line for each sample.
9644 Default value is @code{point}.
9647 Set the number of samples which are printed on the same column. A
9648 larger value will decrease the frame rate. Must be a positive
9649 integer. This option can be set only if the value for @var{rate}
9650 is not explicitly specified.
9653 Set the (approximate) output frame rate. This is done by setting the
9654 option @var{n}. Default value is "25".
9658 @subsection Examples
9662 Output the input file audio and the corresponding video representation
9665 amovie=a.mp3,asplit[out0],showwaves[out1]
9669 Create a synthetic signal and show it with showwaves, forcing a
9670 frame rate of 30 frames per second:
9672 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
9676 @section split, asplit
9678 Split input into several identical outputs.
9680 @code{asplit} works with audio input, @code{split} with video.
9682 The filter accepts a single parameter which specifies the number of outputs. If
9683 unspecified, it defaults to 2.
9685 @subsection Examples
9689 Create two separate outputs from the same input:
9691 [in] split [out0][out1]
9695 To create 3 or more outputs, you need to specify the number of
9698 [in] asplit=3 [out0][out1][out2]
9702 Create two separate outputs from the same input, one cropped and
9705 [in] split [splitout1][splitout2];
9706 [splitout1] crop=100:100:0:0 [cropout];
9707 [splitout2] pad=200:200:100:100 [padout];
9711 Create 5 copies of the input audio with @command{ffmpeg}:
9713 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
9719 Receive commands sent through a libzmq client, and forward them to
9720 filters in the filtergraph.
9722 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
9723 must be inserted between two video filters, @code{azmq} between two
9726 To enable these filters you need to install the libzmq library and
9727 headers and configure FFmpeg with @code{--enable-libzmq}.
9729 For more information about libzmq see:
9730 @url{http://www.zeromq.org/}
9732 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
9733 receives messages sent through a network interface defined by the
9734 @option{bind_address} option.
9736 The received message must be in the form:
9738 @var{TARGET} @var{COMMAND} [@var{ARG}]
9741 @var{TARGET} specifies the target of the command, usually the name of
9742 the filter class or a specific filter instance name.
9744 @var{COMMAND} specifies the name of the command for the target filter.
9746 @var{ARG} is optional and specifies the optional argument list for the
9747 given @var{COMMAND}.
9749 Upon reception, the message is processed and the corresponding command
9750 is injected into the filtergraph. Depending on the result, the filter
9751 will send a reply to the client, adopting the format:
9753 @var{ERROR_CODE} @var{ERROR_REASON}
9757 @var{MESSAGE} is optional.
9759 @subsection Examples
9761 Look at @file{tools/zmqsend} for an example of a zmq client which can
9762 be used to send commands processed by these filters.
9764 Consider the following filtergraph generated by @command{ffplay}
9766 ffplay -dumpgraph 1 -f lavfi "
9767 color=s=100x100:c=red [l];
9768 color=s=100x100:c=blue [r];
9769 nullsrc=s=200x100, zmq [bg];
9770 [bg][l] overlay [bg+l];
9771 [bg+l][r] overlay=x=100 "
9774 To change the color of the left side of the video, the following
9775 command can be used:
9777 echo Parsed_color_0 c yellow | tools/zmqsend
9780 To change the right side:
9782 echo Parsed_color_1 c pink | tools/zmqsend
9785 @c man end MULTIMEDIA FILTERS
9787 @chapter Multimedia Sources
9788 @c man begin MULTIMEDIA SOURCES
9790 Below is a description of the currently available multimedia sources.
9794 This is the same as @ref{movie} source, except it selects an audio
9800 Read audio and/or video stream(s) from a movie container.
9802 This filter accepts the following options:
9806 The name of the resource to read (not necessarily a file but also a device or a
9807 stream accessed through some protocol).
9809 @item format_name, f
9810 Specifies the format assumed for the movie to read, and can be either
9811 the name of a container or an input device. If not specified the
9812 format is guessed from @var{movie_name} or by probing.
9814 @item seek_point, sp
9815 Specifies the seek point in seconds, the frames will be output
9816 starting from this seek point, the parameter is evaluated with
9817 @code{av_strtod} so the numerical value may be suffixed by an IS
9818 postfix. Default value is "0".
9821 Specifies the streams to read. Several streams can be specified,
9822 separated by "+". The source will then have as many outputs, in the
9823 same order. The syntax is explained in the ``Stream specifiers''
9824 section in the ffmpeg manual. Two special names, "dv" and "da" specify
9825 respectively the default (best suited) video and audio stream. Default
9826 is "dv", or "da" if the filter is called as "amovie".
9828 @item stream_index, si
9829 Specifies the index of the video stream to read. If the value is -1,
9830 the best suited video stream will be automatically selected. Default
9831 value is "-1". Deprecated. If the filter is called "amovie", it will select
9832 audio instead of video.
9835 Specifies how many times to read the stream in sequence.
9836 If the value is less than 1, the stream will be read again and again.
9837 Default value is "1".
9839 Note that when the movie is looped the source timestamps are not
9840 changed, so it will generate non monotonically increasing timestamps.
9843 This filter allows to overlay a second video on top of main input of
9844 a filtergraph as shown in this graph:
9846 input -----------> deltapts0 --> overlay --> output
9849 movie --> scale--> deltapts1 -------+
9852 @subsection Examples
9856 Skip 3.2 seconds from the start of the avi file in.avi, and overlay it
9857 on top of the input labelled as "in":
9859 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
9860 [in] setpts=PTS-STARTPTS [main];
9861 [main][over] overlay=16:16 [out]
9865 Read from a video4linux2 device, and overlay it on top of the input
9868 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
9869 [in] setpts=PTS-STARTPTS [main];
9870 [main][over] overlay=16:16 [out]
9874 Read the first video stream and the audio stream with id 0x81 from
9875 dvd.vob; the video is connected to the pad named "video" and the audio is
9876 connected to the pad named "audio":
9878 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
9882 @c man end MULTIMEDIA SOURCES