1 @chapter Filtering Introduction
2 @c man begin FILTERING INTRODUCTION
4 Filtering in FFmpeg is enabled through the libavfilter library.
6 In libavfilter, a filter can have multiple inputs and multiple
8 To illustrate the sorts of things that are possible, we consider the
13 input --> split ---------------------> overlay --> output
16 +-----> crop --> vflip -------+
19 This filtergraph splits the input stream in two streams, then sends one
20 stream through the crop filter and the vflip filter, before merging it
21 back with the other stream by overlaying it on top. You can use the
22 following command to achieve this:
25 ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
28 The result will be that the top half of the video is mirrored
29 onto the bottom half of the output video.
31 Filters in the same linear chain are separated by commas, and distinct
32 linear chains of filters are separated by semicolons. In our example,
33 @var{crop,vflip} are in one linear chain, @var{split} and
34 @var{overlay} are separately in another. The points where the linear
35 chains join are labelled by names enclosed in square brackets. In the
36 example, the split filter generates two outputs that are associated to
37 the labels @var{[main]} and @var{[tmp]}.
39 The stream sent to the second output of @var{split}, labelled as
40 @var{[tmp]}, is processed through the @var{crop} filter, which crops
41 away the lower half part of the video, and then vertically flipped. The
42 @var{overlay} filter takes in input the first unchanged output of the
43 split filter (which was labelled as @var{[main]}), and overlay on its
44 lower half the output generated by the @var{crop,vflip} filterchain.
46 Some filters take in input a list of parameters: they are specified
47 after the filter name and an equal sign, and are separated from each other
50 There exist so-called @var{source filters} that do not have an
51 audio/video input, and @var{sink filters} that will not have audio/video
54 @c man end FILTERING INTRODUCTION
57 @c man begin GRAPH2DOT
59 The @file{graph2dot} program included in the FFmpeg @file{tools}
60 directory can be used to parse a filtergraph description and issue a
61 corresponding textual representation in the dot language.
68 to see how to use @file{graph2dot}.
70 You can then pass the dot description to the @file{dot} program (from
71 the graphviz suite of programs) and obtain a graphical representation
74 For example the sequence of commands:
76 echo @var{GRAPH_DESCRIPTION} | \
77 tools/graph2dot -o graph.tmp && \
78 dot -Tpng graph.tmp -o graph.png && \
82 can be used to create and display an image representing the graph
83 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
84 a complete self-contained graph, with its inputs and outputs explicitly defined.
85 For example if your command line is of the form:
87 ffmpeg -i infile -vf scale=640:360 outfile
89 your @var{GRAPH_DESCRIPTION} string will need to be of the form:
91 nullsrc,scale=640:360,nullsink
93 you may also need to set the @var{nullsrc} parameters and add a @var{format}
94 filter in order to simulate a specific input file.
98 @chapter Filtergraph description
99 @c man begin FILTERGRAPH DESCRIPTION
101 A filtergraph is a directed graph of connected filters. It can contain
102 cycles, and there can be multiple links between a pair of
103 filters. Each link has one input pad on one side connecting it to one
104 filter from which it takes its input, and one output pad on the other
105 side connecting it to one filter accepting its output.
107 Each filter in a filtergraph is an instance of a filter class
108 registered in the application, which defines the features and the
109 number of input and output pads of the filter.
111 A filter with no input pads is called a "source", and a filter with no
112 output pads is called a "sink".
114 @anchor{Filtergraph syntax}
115 @section Filtergraph syntax
117 A filtergraph has a textual representation, which is
118 recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
119 options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the
120 @code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} functions defined in
121 @file{libavfilter/avfilter.h}.
123 A filterchain consists of a sequence of connected filters, each one
124 connected to the previous one in the sequence. A filterchain is
125 represented by a list of ","-separated filter descriptions.
127 A filtergraph consists of a sequence of filterchains. A sequence of
128 filterchains is represented by a list of ";"-separated filterchain
131 A filter is represented by a string of the form:
132 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
134 @var{filter_name} is the name of the filter class of which the
135 described filter is an instance of, and has to be the name of one of
136 the filter classes registered in the program.
137 The name of the filter class is optionally followed by a string
140 @var{arguments} is a string which contains the parameters used to
141 initialize the filter instance. It may have one of two forms:
145 A ':'-separated list of @var{key=value} pairs.
148 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
149 the option names in the order they are declared. E.g. the @code{fade} filter
150 declares three options in this order -- @option{type}, @option{start_frame} and
151 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
152 @var{in} is assigned to the option @option{type}, @var{0} to
153 @option{start_frame} and @var{30} to @option{nb_frames}.
156 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
157 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
158 follow the same constraints order of the previous point. The following
159 @var{key=value} pairs can be set in any preferred order.
163 If the option value itself is a list of items (e.g. the @code{format} filter
164 takes a list of pixel formats), the items in the list are usually separated by
167 The list of arguments can be quoted using the character "'" as initial
168 and ending mark, and the character '\' for escaping the characters
169 within the quoted text; otherwise the argument string is considered
170 terminated when the next special character (belonging to the set
171 "[]=;,") is encountered.
173 The name and arguments of the filter are optionally preceded and
174 followed by a list of link labels.
175 A link label allows one to name a link and associate it to a filter output
176 or input pad. The preceding labels @var{in_link_1}
177 ... @var{in_link_N}, are associated to the filter input pads,
178 the following labels @var{out_link_1} ... @var{out_link_M}, are
179 associated to the output pads.
181 When two link labels with the same name are found in the
182 filtergraph, a link between the corresponding input and output pad is
185 If an output pad is not labelled, it is linked by default to the first
186 unlabelled input pad of the next filter in the filterchain.
187 For example in the filterchain
189 nullsrc, split[L1], [L2]overlay, nullsink
191 the split filter instance has two output pads, and the overlay filter
192 instance two input pads. The first output pad of split is labelled
193 "L1", the first input pad of overlay is labelled "L2", and the second
194 output pad of split is linked to the second input pad of overlay,
195 which are both unlabelled.
197 In a complete filterchain all the unlabelled filter input and output
198 pads must be connected. A filtergraph is considered valid if all the
199 filter input and output pads of all the filterchains are connected.
201 Libavfilter will automatically insert @ref{scale} filters where format
202 conversion is required. It is possible to specify swscale flags
203 for those automatically inserted scalers by prepending
204 @code{sws_flags=@var{flags};}
205 to the filtergraph description.
207 Here is a BNF description of the filtergraph syntax:
209 @var{NAME} ::= sequence of alphanumeric characters and '_'
210 @var{LINKLABEL} ::= "[" @var{NAME} "]"
211 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
212 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
213 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
214 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
215 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
218 @section Notes on filtergraph escaping
220 Filtergraph description composition entails several levels of
221 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
222 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
223 information about the employed escaping procedure.
225 A first level escaping affects the content of each filter option
226 value, which may contain the special character @code{:} used to
227 separate values, or one of the escaping characters @code{\'}.
229 A second level escaping affects the whole filter description, which
230 may contain the escaping characters @code{\'} or the special
231 characters @code{[],;} used by the filtergraph description.
233 Finally, when you specify a filtergraph on a shell commandline, you
234 need to perform a third level escaping for the shell special
235 characters contained within it.
237 For example, consider the following string to be embedded in
238 the @ref{drawtext} filter description @option{text} value:
240 this is a 'string': may contain one, or more, special characters
243 This string contains the @code{'} special escaping character, and the
244 @code{:} special character, so it needs to be escaped in this way:
246 text=this is a \'string\'\: may contain one, or more, special characters
249 A second level of escaping is required when embedding the filter
250 description in a filtergraph description, in order to escape all the
251 filtergraph special characters. Thus the example above becomes:
253 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
255 (note that in addition to the @code{\'} escaping special characters,
256 also @code{,} needs to be escaped).
258 Finally an additional level of escaping is needed when writing the
259 filtergraph description in a shell command, which depends on the
260 escaping rules of the adopted shell. For example, assuming that
261 @code{\} is special and needs to be escaped with another @code{\}, the
262 previous string will finally result in:
264 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
267 @chapter Timeline editing
269 Some filters support a generic @option{enable} option. For the filters
270 supporting timeline editing, this option can be set to an expression which is
271 evaluated before sending a frame to the filter. If the evaluation is non-zero,
272 the filter will be enabled, otherwise the frame will be sent unchanged to the
273 next filter in the filtergraph.
275 The expression accepts the following values:
278 timestamp expressed in seconds, NAN if the input timestamp is unknown
281 sequential number of the input frame, starting from 0
284 the position in the file of the input frame, NAN if unknown
287 Additionally, these filters support an @option{enable} command that can be used
288 to re-define the expression.
290 Like any other filtering option, the @option{enable} option follows the same
293 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
294 minutes, and a @ref{curves} filter starting at 3 seconds:
296 smartblur = enable='between(t,10,3*60)',
297 curves = enable='gte(t,3)' : preset=cross_process
300 @c man end FILTERGRAPH DESCRIPTION
302 @chapter Audio Filters
303 @c man begin AUDIO FILTERS
305 When you configure your FFmpeg build, you can disable any of the
306 existing filters using @code{--disable-filters}.
307 The configure output will show the audio filters included in your
310 Below is a description of the currently available audio filters.
314 Convert the input audio format to the specified formats.
316 @emph{This filter is deprecated. Use @ref{aformat} instead.}
318 The filter accepts a string of the form:
319 "@var{sample_format}:@var{channel_layout}".
321 @var{sample_format} specifies the sample format, and can be a string or the
322 corresponding numeric value defined in @file{libavutil/samplefmt.h}. Use 'p'
323 suffix for a planar sample format.
325 @var{channel_layout} specifies the channel layout, and can be a string
326 or the corresponding number value defined in @file{libavutil/channel_layout.h}.
328 The special parameter "auto", signifies that the filter will
329 automatically select the output format depending on the output filter.
335 Convert input to float, planar, stereo:
341 Convert input to unsigned 8-bit, automatically select out channel layout:
349 Delay one or more audio channels.
351 Samples in delayed channel are filled with silence.
353 The filter accepts the following option:
357 Set list of delays in milliseconds for each channel separated by '|'.
358 At least one delay greater than 0 should be provided.
359 Unused delays will be silently ignored. If number of given delays is
360 smaller than number of channels all remaining channels will not be delayed.
367 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
368 the second channel (and any other channels that may be present) unchanged.
376 Apply echoing to the input audio.
378 Echoes are reflected sound and can occur naturally amongst mountains
379 (and sometimes large buildings) when talking or shouting; digital echo
380 effects emulate this behaviour and are often used to help fill out the
381 sound of a single instrument or vocal. The time difference between the
382 original signal and the reflection is the @code{delay}, and the
383 loudness of the reflected signal is the @code{decay}.
384 Multiple echoes can have different delays and decays.
386 A description of the accepted parameters follows.
390 Set input gain of reflected signal. Default is @code{0.6}.
393 Set output gain of reflected signal. Default is @code{0.3}.
396 Set list of time intervals in milliseconds between original signal and reflections
397 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
398 Default is @code{1000}.
401 Set list of loudnesses of reflected signals separated by '|'.
402 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
403 Default is @code{0.5}.
410 Make it sound as if there are twice as many instruments as are actually playing:
412 aecho=0.8:0.88:60:0.4
416 If delay is very short, then it sound like a (metallic) robot playing music:
422 A longer delay will sound like an open air concert in the mountains:
424 aecho=0.8:0.9:1000:0.3
428 Same as above but with one more mountain:
430 aecho=0.8:0.9:1000|1800:0.3|0.25
436 Modify an audio signal according to the specified expressions.
438 This filter accepts one or more expressions (one for each channel),
439 which are evaluated and used to modify a corresponding audio signal.
441 It accepts the following parameters:
445 Set the '|'-separated expressions list for each separate channel. If
446 the number of input channels is greater than the number of
447 expressions, the last specified expression is used for the remaining
450 @item channel_layout, c
451 Set output channel layout. If not specified, the channel layout is
452 specified by the number of expressions. If set to @samp{same}, it will
453 use by default the same input channel layout.
456 Each expression in @var{exprs} can contain the following constants and functions:
460 channel number of the current expression
463 number of the evaluated sample, starting from 0
469 time of the evaluated sample expressed in seconds
472 @item nb_out_channels
473 input and output number of channels
476 the value of input channel with number @var{CH}
479 Note: this filter is slow. For faster processing you should use a
488 aeval=val(ch)/2:c=same
492 Invert phase of the second channel:
500 Apply fade-in/out effect to input audio.
502 A description of the accepted parameters follows.
506 Specify the effect type, can be either @code{in} for fade-in, or
507 @code{out} for a fade-out effect. Default is @code{in}.
509 @item start_sample, ss
510 Specify the number of the start sample for starting to apply the fade
511 effect. Default is 0.
514 Specify the number of samples for which the fade effect has to last. At
515 the end of the fade-in effect the output audio will have the same
516 volume as the input audio, at the end of the fade-out transition
517 the output audio will be silence. Default is 44100.
520 Specify time for starting to apply the fade effect. Default is 0.
521 The accepted syntax is:
523 [-]HH[:MM[:SS[.m...]]]
526 See also the function @code{av_parse_time()}.
527 If set this option is used instead of @var{start_sample} one.
530 Specify the duration for which the fade effect has to last. Default is 0.
531 The accepted syntax is:
533 [-]HH[:MM[:SS[.m...]]]
536 See also the function @code{av_parse_time()}.
537 At the end of the fade-in effect the output audio will have the same
538 volume as the input audio, at the end of the fade-out transition
539 the output audio will be silence.
540 If set this option is used instead of @var{nb_samples} one.
543 Set curve for fade transition.
545 It accepts the following values:
548 select triangular, linear slope (default)
550 select quarter of sine wave
552 select half of sine wave
554 select exponential sine wave
558 select inverted parabola
574 Fade in first 15 seconds of audio:
580 Fade out last 25 seconds of a 900 seconds audio:
582 afade=t=out:st=875:d=25
589 Set output format constraints for the input audio. The framework will
590 negotiate the most appropriate format to minimize conversions.
592 It accepts the following parameters:
596 A '|'-separated list of requested sample formats.
599 A '|'-separated list of requested sample rates.
601 @item channel_layouts
602 A '|'-separated list of requested channel layouts.
604 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
605 for the required syntax.
608 If a parameter is omitted, all values are allowed.
610 Force the output to either unsigned 8-bit or signed 16-bit stereo
612 aformat=sample_fmts=u8|s16:channel_layouts=stereo
617 Apply a two-pole all-pass filter with central frequency (in Hz)
618 @var{frequency}, and filter-width @var{width}.
619 An all-pass filter changes the audio's frequency to phase relationship
620 without changing its frequency to amplitude relationship.
622 The filter accepts the following options:
629 Set method to specify band-width of filter.
642 Specify the band-width of a filter in width_type units.
647 Merge two or more audio streams into a single multi-channel stream.
649 The filter accepts the following options:
654 Set the number of inputs. Default is 2.
658 If the channel layouts of the inputs are disjoint, and therefore compatible,
659 the channel layout of the output will be set accordingly and the channels
660 will be reordered as necessary. If the channel layouts of the inputs are not
661 disjoint, the output will have all the channels of the first input then all
662 the channels of the second input, in that order, and the channel layout of
663 the output will be the default value corresponding to the total number of
666 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
667 is FC+BL+BR, then the output will be in 5.1, with the channels in the
668 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
669 first input, b1 is the first channel of the second input).
671 On the other hand, if both input are in stereo, the output channels will be
672 in the default order: a1, a2, b1, b2, and the channel layout will be
673 arbitrarily set to 4.0, which may or may not be the expected value.
675 All inputs must have the same sample rate, and format.
677 If inputs do not have the same duration, the output will stop with the
684 Merge two mono files into a stereo stream:
686 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
690 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
692 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
698 Mixes multiple audio inputs into a single output.
700 Note that this filter only supports float samples (the @var{amerge}
701 and @var{pan} audio filters support many formats). If the @var{amix}
702 input has integer samples then @ref{aresample} will be automatically
703 inserted to perform the conversion to float samples.
707 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
709 will mix 3 input audio streams to a single output with the same duration as the
710 first input and a dropout transition time of 3 seconds.
712 It accepts the following parameters:
716 The number of inputs. If unspecified, it defaults to 2.
719 How to determine the end-of-stream.
723 The duration of the longest input. (default)
726 The duration of the shortest input.
729 The duration of the first input.
733 @item dropout_transition
734 The transition time, in seconds, for volume renormalization when an input
735 stream ends. The default value is 2 seconds.
741 Pass the audio source unchanged to the output.
745 Pad the end of a audio stream with silence, this can be used together with
746 -shortest to extend audio streams to the same length as the video stream.
749 Add a phasing effect to the input audio.
751 A phaser filter creates series of peaks and troughs in the frequency spectrum.
752 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
754 A description of the accepted parameters follows.
758 Set input gain. Default is 0.4.
761 Set output gain. Default is 0.74
764 Set delay in milliseconds. Default is 3.0.
767 Set decay. Default is 0.4.
770 Set modulation speed in Hz. Default is 0.5.
773 Set modulation type. Default is triangular.
775 It accepts the following values:
785 Resample the input audio to the specified parameters, using the
786 libswresample library. If none are specified then the filter will
787 automatically convert between its input and output.
789 This filter is also able to stretch/squeeze the audio data to make it match
790 the timestamps or to inject silence / cut out audio to make it match the
791 timestamps, do a combination of both or do neither.
793 The filter accepts the syntax
794 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
795 expresses a sample rate and @var{resampler_options} is a list of
796 @var{key}=@var{value} pairs, separated by ":". See the
797 ffmpeg-resampler manual for the complete list of supported options.
803 Resample the input audio to 44100Hz:
809 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
810 samples per second compensation:
816 @section asetnsamples
818 Set the number of samples per each output audio frame.
820 The last output packet may contain a different number of samples, as
821 the filter will flush all the remaining samples when the input audio
824 The filter accepts the following options:
828 @item nb_out_samples, n
829 Set the number of frames per each output audio frame. The number is
830 intended as the number of samples @emph{per each channel}.
831 Default value is 1024.
834 If set to 1, the filter will pad the last audio frame with zeroes, so
835 that the last frame will contain the same number of samples as the
836 previous ones. Default value is 1.
839 For example, to set the number of per-frame samples to 1234 and
840 disable padding for the last frame, use:
842 asetnsamples=n=1234:p=0
847 Set the sample rate without altering the PCM data.
848 This will result in a change of speed and pitch.
850 The filter accepts the following options:
854 Set the output sample rate. Default is 44100 Hz.
859 Show a line containing various information for each input audio frame.
860 The input audio is not modified.
862 The shown line contains a sequence of key/value pairs of the form
863 @var{key}:@var{value}.
865 It accepts the following parameters:
869 The (sequential) number of the input frame, starting from 0.
872 The presentation timestamp of the input frame, in time base units; the time base
873 depends on the filter input pad, and is usually 1/@var{sample_rate}.
876 The presentation timestamp of the input frame in seconds.
879 position of the frame in the input stream, -1 if this information in
880 unavailable and/or meaningless (for example in case of synthetic audio)
889 The sample rate for the audio frame.
892 The number of samples (per channel) in the frame.
895 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
896 audio, the data is treated as if all the planes were concatenated.
898 @item plane_checksums
899 A list of Adler-32 checksums for each data plane.
904 Display time domain statistical information about the audio channels.
905 Statistics are calculated and displayed for each audio channel and,
906 where applicable, an overall figure is also given.
908 It accepts the following option:
911 Short window length in seconds, used for peak and trough RMS measurement.
912 Default is @code{0.05} (50 miliseconds). Allowed range is @code{[0.1 - 10]}.
915 A description of each shown parameter follows:
919 Mean amplitude displacement from zero.
922 Minimal sample level.
925 Maximal sample level.
929 Standard peak and RMS level measured in dBFS.
933 Peak and trough values for RMS level measured over a short window.
936 Standard ratio of peak to RMS level (note: not in dB).
939 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
940 (i.e. either @var{Min level} or @var{Max level}).
943 Number of occasions (not the number of samples) that the signal attained either
944 @var{Min level} or @var{Max level}.
949 Forward two audio streams and control the order the buffers are forwarded.
951 The filter accepts the following options:
955 Set the expression deciding which stream should be
956 forwarded next: if the result is negative, the first stream is forwarded; if
957 the result is positive or zero, the second stream is forwarded. It can use
958 the following variables:
962 number of buffers forwarded so far on each stream
964 number of samples forwarded so far on each stream
966 current timestamp of each stream
969 The default value is @code{t1-t2}, which means to always forward the stream
970 that has a smaller timestamp.
975 Stress-test @code{amerge} by randomly sending buffers on the wrong
976 input, while avoiding too much of a desynchronization:
978 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
979 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
985 Synchronize audio data with timestamps by squeezing/stretching it and/or
986 dropping samples/adding silence when needed.
988 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
990 It accepts the following parameters:
994 Enable stretching/squeezing the data to make it match the timestamps. Disabled
995 by default. When disabled, time gaps are covered with silence.
998 The minimum difference between timestamps and audio data (in seconds) to trigger
999 adding/dropping samples. The default value is 0.1. If you get an imperfect
1000 sync with this filter, try setting this parameter to 0.
1003 The maximum compensation in samples per second. Only relevant with compensate=1.
1004 The default value is 500.
1007 Assume that the first PTS should be this value. The time base is 1 / sample
1008 rate. This allows for padding/trimming at the start of the stream. By default,
1009 no assumption is made about the first frame's expected PTS, so no padding or
1010 trimming is done. For example, this could be set to 0 to pad the beginning with
1011 silence if an audio stream starts after the video stream or to trim any samples
1012 with a negative PTS due to encoder delay.
1020 The filter accepts exactly one parameter, the audio tempo. If not
1021 specified then the filter will assume nominal 1.0 tempo. Tempo must
1022 be in the [0.5, 2.0] range.
1024 @subsection Examples
1028 Slow down audio to 80% tempo:
1034 To speed up audio to 125% tempo:
1042 Trim the input so that the output contains one continuous subpart of the input.
1044 It accepts the following parameters:
1047 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1048 sample with the timestamp @var{start} will be the first sample in the output.
1051 Specify time of the first audio sample that will be dropped, i.e. the
1052 audio sample immediately preceding the one with the timestamp @var{end} will be
1053 the last sample in the output.
1056 Same as @var{start}, except this option sets the start timestamp in samples
1060 Same as @var{end}, except this option sets the end timestamp in samples instead
1064 The maximum duration of the output in seconds.
1067 The number of the first sample that should be output.
1070 The number of the first sample that should be dropped.
1073 @option{start}, @option{end}, @option{duration} are expressed as time
1074 duration specifications, check the "Time duration" section in the
1075 ffmpeg-utils manual.
1077 Note that the first two sets of the start/end options and the @option{duration}
1078 option look at the frame timestamp, while the _sample options simply count the
1079 samples that pass through the filter. So start/end_pts and start/end_sample will
1080 give different results when the timestamps are wrong, inexact or do not start at
1081 zero. Also note that this filter does not modify the timestamps. If you wish
1082 to have the output timestamps start at zero, insert the asetpts filter after the
1085 If multiple start or end options are set, this filter tries to be greedy and
1086 keep all samples that match at least one of the specified constraints. To keep
1087 only the part that matches all the constraints at once, chain multiple atrim
1090 The defaults are such that all the input is kept. So it is possible to set e.g.
1091 just the end values to keep everything before the specified time.
1096 Drop everything except the second minute of input:
1098 ffmpeg -i INPUT -af atrim=60:120
1102 Keep only the first 1000 samples:
1104 ffmpeg -i INPUT -af atrim=end_sample=1000
1111 Apply a two-pole Butterworth band-pass filter with central
1112 frequency @var{frequency}, and (3dB-point) band-width width.
1113 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1114 instead of the default: constant 0dB peak gain.
1115 The filter roll off at 6dB per octave (20dB per decade).
1117 The filter accepts the following options:
1121 Set the filter's central frequency. Default is @code{3000}.
1124 Constant skirt gain if set to 1. Defaults to 0.
1127 Set method to specify band-width of filter.
1140 Specify the band-width of a filter in width_type units.
1145 Apply a two-pole Butterworth band-reject filter with central
1146 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1147 The filter roll off at 6dB per octave (20dB per decade).
1149 The filter accepts the following options:
1153 Set the filter's central frequency. Default is @code{3000}.
1156 Set method to specify band-width of filter.
1169 Specify the band-width of a filter in width_type units.
1174 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1175 shelving filter with a response similar to that of a standard
1176 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1178 The filter accepts the following options:
1182 Give the gain at 0 Hz. Its useful range is about -20
1183 (for a large cut) to +20 (for a large boost).
1184 Beware of clipping when using a positive gain.
1187 Set the filter's central frequency and so can be used
1188 to extend or reduce the frequency range to be boosted or cut.
1189 The default value is @code{100} Hz.
1192 Set method to specify band-width of filter.
1205 Determine how steep is the filter's shelf transition.
1210 Apply a biquad IIR filter with the given coefficients.
1211 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1212 are the numerator and denominator coefficients respectively.
1215 Bauer stereo to binaural transformation, which improves headphone listening of
1216 stereo audio records.
1218 It accepts the following parameters:
1222 Pre-defined crossfeed level.
1226 Default level (fcut=700, feed=50).
1229 Chu Moy circuit (fcut=700, feed=60).
1232 Jan Meier circuit (fcut=650, feed=95).
1237 Cut frequency (in Hz).
1246 Remap input channels to new locations.
1248 It accepts the following parameters:
1250 @item channel_layout
1251 The channel layout of the output stream.
1254 Map channels from input to output. The argument is a '|'-separated list of
1255 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1256 @var{in_channel} form. @var{in_channel} can be either the name of the input
1257 channel (e.g. FL for front left) or its index in the input channel layout.
1258 @var{out_channel} is the name of the output channel or its index in the output
1259 channel layout. If @var{out_channel} is not given then it is implicitly an
1260 index, starting with zero and increasing by one for each mapping.
1263 If no mapping is present, the filter will implicitly map input channels to
1264 output channels, preserving indices.
1266 For example, assuming a 5.1+downmix input MOV file,
1268 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1270 will create an output WAV file tagged as stereo from the downmix channels of
1273 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1275 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1278 @section channelsplit
1280 Split each channel from an input audio stream into a separate output stream.
1282 It accepts the following parameters:
1284 @item channel_layout
1285 The channel layout of the input stream. The default is "stereo".
1288 For example, assuming a stereo input MP3 file,
1290 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1292 will create an output Matroska file with two audio streams, one containing only
1293 the left channel and the other the right channel.
1295 Split a 5.1 WAV file into per-channel files:
1297 ffmpeg -i in.wav -filter_complex
1298 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1299 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1300 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1305 Compress or expand the audio's dynamic range.
1307 It accepts the following parameters:
1313 A list of times in seconds for each channel over which the instantaneous level
1314 of the input signal is averaged to determine its volume. @var{attacks} refers to
1315 increase of volume and @var{decays} refers to decrease of volume. For most
1316 situations, the attack time (response to the audio getting louder) should be
1317 shorter than the decay time, because the human ear is more sensitive to sudden
1318 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1319 a typical value for decay is 0.8 seconds.
1322 A list of points for the transfer function, specified in dB relative to the
1323 maximum possible signal amplitude. Each key points list must be defined using
1324 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1325 @code{x0/y0 x1/y1 x2/y2 ....}
1327 The input values must be in strictly increasing order but the transfer function
1328 does not have to be monotonically rising. The point @code{0/0} is assumed but
1329 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1330 function are @code{-70/-70|-60/-20}.
1333 Set the curve radius in dB for all joints. It defaults to 0.01.
1336 Set the additional gain in dB to be applied at all points on the transfer
1337 function. This allows for easy adjustment of the overall gain.
1341 Set an initial volume, in dB, to be assumed for each channel when filtering
1342 starts. This permits the user to supply a nominal level initially, so that, for
1343 example, a very large gain is not applied to initial signal levels before the
1344 companding has begun to operate. A typical value for audio which is initially
1345 quiet is -90 dB. It defaults to 0.
1348 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1349 delayed before being fed to the volume adjuster. Specifying a delay
1350 approximately equal to the attack/decay times allows the filter to effectively
1351 operate in predictive rather than reactive mode. It defaults to 0.
1355 @subsection Examples
1359 Make music with both quiet and loud passages suitable for listening to in a
1362 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1366 A noise gate for when the noise is at a lower level than the signal:
1368 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1372 Here is another noise gate, this time for when the noise is at a higher level
1373 than the signal (making it, in some ways, similar to squelch):
1375 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1381 Make audio easier to listen to on headphones.
1383 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1384 so that when listened to on headphones the stereo image is moved from
1385 inside your head (standard for headphones) to outside and in front of
1386 the listener (standard for speakers).
1392 Apply a two-pole peaking equalisation (EQ) filter. With this
1393 filter, the signal-level at and around a selected frequency can
1394 be increased or decreased, whilst (unlike bandpass and bandreject
1395 filters) that at all other frequencies is unchanged.
1397 In order to produce complex equalisation curves, this filter can
1398 be given several times, each with a different central frequency.
1400 The filter accepts the following options:
1404 Set the filter's central frequency in Hz.
1407 Set method to specify band-width of filter.
1420 Specify the band-width of a filter in width_type units.
1423 Set the required gain or attenuation in dB.
1424 Beware of clipping when using a positive gain.
1427 @subsection Examples
1430 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1432 equalizer=f=1000:width_type=h:width=200:g=-10
1436 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1438 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1444 Apply a high-pass filter with 3dB point frequency.
1445 The filter can be either single-pole, or double-pole (the default).
1446 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1448 The filter accepts the following options:
1452 Set frequency in Hz. Default is 3000.
1455 Set number of poles. Default is 2.
1458 Set method to specify band-width of filter.
1471 Specify the band-width of a filter in width_type units.
1472 Applies only to double-pole filter.
1473 The default is 0.707q and gives a Butterworth response.
1478 Join multiple input streams into one multi-channel stream.
1480 It accepts the following parameters:
1484 The number of input streams. It defaults to 2.
1486 @item channel_layout
1487 The desired output channel layout. It defaults to stereo.
1490 Map channels from inputs to output. The argument is a '|'-separated list of
1491 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1492 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1493 can be either the name of the input channel (e.g. FL for front left) or its
1494 index in the specified input stream. @var{out_channel} is the name of the output
1498 The filter will attempt to guess the mappings when they are not specified
1499 explicitly. It does so by first trying to find an unused matching input channel
1500 and if that fails it picks the first unused input channel.
1502 Join 3 inputs (with properly set channel layouts):
1504 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1507 Build a 5.1 output from 6 single-channel streams:
1509 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1510 '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'
1516 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1518 To enable compilation of this filter you need to configure FFmpeg with
1519 @code{--enable-ladspa}.
1523 Specifies the name of LADSPA plugin library to load. If the environment
1524 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1525 each one of the directories specified by the colon separated list in
1526 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1527 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1528 @file{/usr/lib/ladspa/}.
1531 Specifies the plugin within the library. Some libraries contain only
1532 one plugin, but others contain many of them. If this is not set filter
1533 will list all available plugins within the specified library.
1536 Set the '|' separated list of controls which are zero or more floating point
1537 values that determine the behavior of the loaded plugin (for example delay,
1539 Controls need to be defined using the following syntax:
1540 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1541 @var{valuei} is the value set on the @var{i}-th control.
1542 If @option{controls} is set to @code{help}, all available controls and
1543 their valid ranges are printed.
1545 @item sample_rate, s
1546 Specify the sample rate, default to 44100. Only used if plugin have
1550 Set the number of samples per channel per each output frame, default
1551 is 1024. Only used if plugin have zero inputs.
1554 Set the minimum duration of the sourced audio. See the function
1555 @code{av_parse_time()} for the accepted format, also check the "Time duration"
1556 section in the ffmpeg-utils manual.
1557 Note that the resulting duration may be greater than the specified duration,
1558 as the generated audio is always cut at the end of a complete frame.
1559 If not specified, or the expressed duration is negative, the audio is
1560 supposed to be generated forever.
1561 Only used if plugin have zero inputs.
1565 @subsection Examples
1569 List all available plugins within amp (LADSPA example plugin) library:
1575 List all available controls and their valid ranges for @code{vcf_notch}
1576 plugin from @code{VCF} library:
1578 ladspa=f=vcf:p=vcf_notch:c=help
1582 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1585 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1589 Add reverberation to the audio using TAP-plugins
1590 (Tom's Audio Processing plugins):
1592 ladspa=file=tap_reverb:tap_reverb
1596 Generate white noise, with 0.2 amplitude:
1598 ladspa=file=cmt:noise_source_white:c=c0=.2
1602 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1603 @code{C* Audio Plugin Suite} (CAPS) library:
1605 ladspa=file=caps:Click:c=c1=20'
1609 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1611 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1615 @subsection Commands
1617 This filter supports the following commands:
1620 Modify the @var{N}-th control value.
1622 If the specified value is not valid, it is ignored and prior one is kept.
1627 Apply a low-pass filter with 3dB point frequency.
1628 The filter can be either single-pole or double-pole (the default).
1629 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1631 The filter accepts the following options:
1635 Set frequency in Hz. Default is 500.
1638 Set number of poles. Default is 2.
1641 Set method to specify band-width of filter.
1654 Specify the band-width of a filter in width_type units.
1655 Applies only to double-pole filter.
1656 The default is 0.707q and gives a Butterworth response.
1661 Mix channels with specific gain levels. The filter accepts the output
1662 channel layout followed by a set of channels definitions.
1664 This filter is also designed to remap efficiently the channels of an audio
1667 The filter accepts parameters of the form:
1668 "@var{l}:@var{outdef}:@var{outdef}:..."
1672 output channel layout or number of channels
1675 output channel specification, of the form:
1676 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1679 output channel to define, either a channel name (FL, FR, etc.) or a channel
1680 number (c0, c1, etc.)
1683 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1686 input channel to use, see out_name for details; it is not possible to mix
1687 named and numbered input channels
1690 If the `=' in a channel specification is replaced by `<', then the gains for
1691 that specification will be renormalized so that the total is 1, thus
1692 avoiding clipping noise.
1694 @subsection Mixing examples
1696 For example, if you want to down-mix from stereo to mono, but with a bigger
1697 factor for the left channel:
1699 pan=1:c0=0.9*c0+0.1*c1
1702 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1703 7-channels surround:
1705 pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1708 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1709 that should be preferred (see "-ac" option) unless you have very specific
1712 @subsection Remapping examples
1714 The channel remapping will be effective if, and only if:
1717 @item gain coefficients are zeroes or ones,
1718 @item only one input per channel output,
1721 If all these conditions are satisfied, the filter will notify the user ("Pure
1722 channel mapping detected"), and use an optimized and lossless method to do the
1725 For example, if you have a 5.1 source and want a stereo audio stream by
1726 dropping the extra channels:
1728 pan="stereo: c0=FL : c1=FR"
1731 Given the same source, you can also switch front left and front right channels
1732 and keep the input channel layout:
1734 pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
1737 If the input is a stereo audio stream, you can mute the front left channel (and
1738 still keep the stereo channel layout) with:
1743 Still with a stereo audio stream input, you can copy the right channel in both
1744 front left and right:
1746 pan="stereo: c0=FR : c1=FR"
1751 ReplayGain scanner filter. This filter takes an audio stream as an input and
1752 outputs it unchanged.
1753 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1757 Convert the audio sample format, sample rate and channel layout. It is
1758 not meant to be used directly.
1760 @section silencedetect
1762 Detect silence in an audio stream.
1764 This filter logs a message when it detects that the input audio volume is less
1765 or equal to a noise tolerance value for a duration greater or equal to the
1766 minimum detected noise duration.
1768 The printed times and duration are expressed in seconds.
1770 The filter accepts the following options:
1774 Set silence duration until notification (default is 2 seconds).
1777 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1778 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1781 @subsection Examples
1785 Detect 5 seconds of silence with -50dB noise tolerance:
1787 silencedetect=n=-50dB:d=5
1791 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1792 tolerance in @file{silence.mp3}:
1794 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1800 Boost or cut treble (upper) frequencies of the audio using a two-pole
1801 shelving filter with a response similar to that of a standard
1802 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1804 The filter accepts the following options:
1808 Give the gain at whichever is the lower of ~22 kHz and the
1809 Nyquist frequency. Its useful range is about -20 (for a large cut)
1810 to +20 (for a large boost). Beware of clipping when using a positive gain.
1813 Set the filter's central frequency and so can be used
1814 to extend or reduce the frequency range to be boosted or cut.
1815 The default value is @code{3000} Hz.
1818 Set method to specify band-width of filter.
1831 Determine how steep is the filter's shelf transition.
1836 Adjust the input audio volume.
1838 It accepts the following parameters:
1842 Set audio volume expression.
1844 Output values are clipped to the maximum value.
1846 The output audio volume is given by the relation:
1848 @var{output_volume} = @var{volume} * @var{input_volume}
1851 The default value for @var{volume} is "1.0".
1854 This parameter represents the mathematical precision.
1856 It determines which input sample formats will be allowed, which affects the
1857 precision of the volume scaling.
1861 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
1863 32-bit floating-point; this limits input sample format to FLT. (default)
1865 64-bit floating-point; this limits input sample format to DBL.
1869 Choose the behaviour on encountering ReplayGain side data in input frames.
1873 Remove ReplayGain side data, ignoring its contents (the default).
1876 Ignore ReplayGain side data, but leave it in the frame.
1879 Prefer the track gain, if present.
1882 Prefer the album gain, if present.
1885 @item replaygain_preamp
1886 Pre-amplification gain in dB to apply to the selected replaygain gain.
1888 Default value for @var{replaygain_preamp} is 0.0.
1891 Set when the volume expression is evaluated.
1893 It accepts the following values:
1896 only evaluate expression once during the filter initialization, or
1897 when the @samp{volume} command is sent
1900 evaluate expression for each incoming frame
1903 Default value is @samp{once}.
1906 The volume expression can contain the following parameters.
1910 frame number (starting at zero)
1913 @item nb_consumed_samples
1914 number of samples consumed by the filter
1916 number of samples in the current frame
1918 original frame position in the file
1924 PTS at start of stream
1926 time at start of stream
1932 last set volume value
1935 Note that when @option{eval} is set to @samp{once} only the
1936 @var{sample_rate} and @var{tb} variables are available, all other
1937 variables will evaluate to NAN.
1939 @subsection Commands
1941 This filter supports the following commands:
1944 Modify the volume expression.
1945 The command accepts the same syntax of the corresponding option.
1947 If the specified expression is not valid, it is kept at its current
1949 @item replaygain_noclip
1950 Prevent clipping by limiting the gain applied.
1952 Default value for @var{replaygain_noclip} is 1.
1956 @subsection Examples
1960 Halve the input audio volume:
1964 volume=volume=-6.0206dB
1967 In all the above example the named key for @option{volume} can be
1968 omitted, for example like in:
1974 Increase input audio power by 6 decibels using fixed-point precision:
1976 volume=volume=6dB:precision=fixed
1980 Fade volume after time 10 with an annihilation period of 5 seconds:
1982 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
1986 @section volumedetect
1988 Detect the volume of the input video.
1990 The filter has no parameters. The input is not modified. Statistics about
1991 the volume will be printed in the log when the input stream end is reached.
1993 In particular it will show the mean volume (root mean square), maximum
1994 volume (on a per-sample basis), and the beginning of a histogram of the
1995 registered volume values (from the maximum value to a cumulated 1/1000 of
1998 All volumes are in decibels relative to the maximum PCM value.
2000 @subsection Examples
2002 Here is an excerpt of the output:
2004 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2005 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2006 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2007 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2008 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2009 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2010 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2011 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2012 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2018 The mean square energy is approximately -27 dB, or 10^-2.7.
2020 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2022 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2025 In other words, raising the volume by +4 dB does not cause any clipping,
2026 raising it by +5 dB causes clipping for 6 samples, etc.
2028 @c man end AUDIO FILTERS
2030 @chapter Audio Sources
2031 @c man begin AUDIO SOURCES
2033 Below is a description of the currently available audio sources.
2037 Buffer audio frames, and make them available to the filter chain.
2039 This source is mainly intended for a programmatic use, in particular
2040 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2042 It accepts the following parameters:
2046 The timebase which will be used for timestamps of submitted frames. It must be
2047 either a floating-point number or in @var{numerator}/@var{denominator} form.
2050 The sample rate of the incoming audio buffers.
2053 The sample format of the incoming audio buffers.
2054 Either a sample format name or its corresponging integer representation from
2055 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2057 @item channel_layout
2058 The channel layout of the incoming audio buffers.
2059 Either a channel layout name from channel_layout_map in
2060 @file{libavutil/channel_layout.c} or its corresponding integer representation
2061 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2064 The number of channels of the incoming audio buffers.
2065 If both @var{channels} and @var{channel_layout} are specified, then they
2070 @subsection Examples
2073 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2076 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2077 Since the sample format with name "s16p" corresponds to the number
2078 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2081 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2086 Generate an audio signal specified by an expression.
2088 This source accepts in input one or more expressions (one for each
2089 channel), which are evaluated and used to generate a corresponding
2092 This source accepts the following options:
2096 Set the '|'-separated expressions list for each separate channel. In case the
2097 @option{channel_layout} option is not specified, the selected channel layout
2098 depends on the number of provided expressions. Otherwise the last
2099 specified expression is applied to the remaining output channels.
2101 @item channel_layout, c
2102 Set the channel layout. The number of channels in the specified layout
2103 must be equal to the number of specified expressions.
2106 Set the minimum duration of the sourced audio. See the function
2107 @code{av_parse_time()} for the accepted format.
2108 Note that the resulting duration may be greater than the specified
2109 duration, as the generated audio is always cut at the end of a
2112 If not specified, or the expressed duration is negative, the audio is
2113 supposed to be generated forever.
2116 Set the number of samples per channel per each output frame,
2119 @item sample_rate, s
2120 Specify the sample rate, default to 44100.
2123 Each expression in @var{exprs} can contain the following constants:
2127 number of the evaluated sample, starting from 0
2130 time of the evaluated sample expressed in seconds, starting from 0
2137 @subsection Examples
2147 Generate a sin signal with frequency of 440 Hz, set sample rate to
2150 aevalsrc="sin(440*2*PI*t):s=8000"
2154 Generate a two channels signal, specify the channel layout (Front
2155 Center + Back Center) explicitly:
2157 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2161 Generate white noise:
2163 aevalsrc="-2+random(0)"
2167 Generate an amplitude modulated signal:
2169 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2173 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2175 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2182 The null audio source, return unprocessed audio frames. It is mainly useful
2183 as a template and to be employed in analysis / debugging tools, or as
2184 the source for filters which ignore the input data (for example the sox
2187 This source accepts the following options:
2191 @item channel_layout, cl
2193 Specifies the channel layout, and can be either an integer or a string
2194 representing a channel layout. The default value of @var{channel_layout}
2197 Check the channel_layout_map definition in
2198 @file{libavutil/channel_layout.c} for the mapping between strings and
2199 channel layout values.
2201 @item sample_rate, r
2202 Specifies the sample rate, and defaults to 44100.
2205 Set the number of samples per requested frames.
2209 @subsection Examples
2213 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2215 anullsrc=r=48000:cl=4
2219 Do the same operation with a more obvious syntax:
2221 anullsrc=r=48000:cl=mono
2225 All the parameters need to be explicitly defined.
2229 Synthesize a voice utterance using the libflite library.
2231 To enable compilation of this filter you need to configure FFmpeg with
2232 @code{--enable-libflite}.
2234 Note that the flite library is not thread-safe.
2236 The filter accepts the following options:
2241 If set to 1, list the names of the available voices and exit
2242 immediately. Default value is 0.
2245 Set the maximum number of samples per frame. Default value is 512.
2248 Set the filename containing the text to speak.
2251 Set the text to speak.
2254 Set the voice to use for the speech synthesis. Default value is
2255 @code{kal}. See also the @var{list_voices} option.
2258 @subsection Examples
2262 Read from file @file{speech.txt}, and synthetize the text using the
2263 standard flite voice:
2265 flite=textfile=speech.txt
2269 Read the specified text selecting the @code{slt} voice:
2271 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2275 Input text to ffmpeg:
2277 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2281 Make @file{ffplay} speak the specified text, using @code{flite} and
2282 the @code{lavfi} device:
2284 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2288 For more information about libflite, check:
2289 @url{http://www.speech.cs.cmu.edu/flite/}
2293 Generate an audio signal made of a sine wave with amplitude 1/8.
2295 The audio signal is bit-exact.
2297 The filter accepts the following options:
2302 Set the carrier frequency. Default is 440 Hz.
2304 @item beep_factor, b
2305 Enable a periodic beep every second with frequency @var{beep_factor} times
2306 the carrier frequency. Default is 0, meaning the beep is disabled.
2308 @item sample_rate, r
2309 Specify the sample rate, default is 44100.
2312 Specify the duration of the generated audio stream.
2314 @item samples_per_frame
2315 Set the number of samples per output frame, default is 1024.
2318 @subsection Examples
2323 Generate a simple 440 Hz sine wave:
2329 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2333 sine=frequency=220:beep_factor=4:duration=5
2338 @c man end AUDIO SOURCES
2340 @chapter Audio Sinks
2341 @c man begin AUDIO SINKS
2343 Below is a description of the currently available audio sinks.
2345 @section abuffersink
2347 Buffer audio frames, and make them available to the end of filter chain.
2349 This sink is mainly intended for programmatic use, in particular
2350 through the interface defined in @file{libavfilter/buffersink.h}
2351 or the options system.
2353 It accepts a pointer to an AVABufferSinkContext structure, which
2354 defines the incoming buffers' formats, to be passed as the opaque
2355 parameter to @code{avfilter_init_filter} for initialization.
2358 Null audio sink; do absolutely nothing with the input audio. It is
2359 mainly useful as a template and for use in analysis / debugging
2362 @c man end AUDIO SINKS
2364 @chapter Video Filters
2365 @c man begin VIDEO FILTERS
2367 When you configure your FFmpeg build, you can disable any of the
2368 existing filters using @code{--disable-filters}.
2369 The configure output will show the video filters included in your
2372 Below is a description of the currently available video filters.
2374 @section alphaextract
2376 Extract the alpha component from the input as a grayscale video. This
2377 is especially useful with the @var{alphamerge} filter.
2381 Add or replace the alpha component of the primary input with the
2382 grayscale value of a second input. This is intended for use with
2383 @var{alphaextract} to allow the transmission or storage of frame
2384 sequences that have alpha in a format that doesn't support an alpha
2387 For example, to reconstruct full frames from a normal YUV-encoded video
2388 and a separate video created with @var{alphaextract}, you might use:
2390 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2393 Since this filter is designed for reconstruction, it operates on frame
2394 sequences without considering timestamps, and terminates when either
2395 input reaches end of stream. This will cause problems if your encoding
2396 pipeline drops frames. If you're trying to apply an image as an
2397 overlay to a video stream, consider the @var{overlay} filter instead.
2401 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2402 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2403 Substation Alpha) subtitles files.
2407 Compute the bounding box for the non-black pixels in the input frame
2410 This filter computes the bounding box containing all the pixels with a
2411 luminance value greater than the minimum allowed value.
2412 The parameters describing the bounding box are printed on the filter
2415 The filter accepts the following option:
2419 Set the minimal luminance value. Default is @code{16}.
2422 @section blackdetect
2424 Detect video intervals that are (almost) completely black. Can be
2425 useful to detect chapter transitions, commercials, or invalid
2426 recordings. Output lines contains the time for the start, end and
2427 duration of the detected black interval expressed in seconds.
2429 In order to display the output lines, you need to set the loglevel at
2430 least to the AV_LOG_INFO value.
2432 The filter accepts the following options:
2435 @item black_min_duration, d
2436 Set the minimum detected black duration expressed in seconds. It must
2437 be a non-negative floating point number.
2439 Default value is 2.0.
2441 @item picture_black_ratio_th, pic_th
2442 Set the threshold for considering a picture "black".
2443 Express the minimum value for the ratio:
2445 @var{nb_black_pixels} / @var{nb_pixels}
2448 for which a picture is considered black.
2449 Default value is 0.98.
2451 @item pixel_black_th, pix_th
2452 Set the threshold for considering a pixel "black".
2454 The threshold expresses the maximum pixel luminance value for which a
2455 pixel is considered "black". The provided value is scaled according to
2456 the following equation:
2458 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2461 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2462 the input video format, the range is [0-255] for YUV full-range
2463 formats and [16-235] for YUV non full-range formats.
2465 Default value is 0.10.
2468 The following example sets the maximum pixel threshold to the minimum
2469 value, and detects only black intervals of 2 or more seconds:
2471 blackdetect=d=2:pix_th=0.00
2476 Detect frames that are (almost) completely black. Can be useful to
2477 detect chapter transitions or commercials. Output lines consist of
2478 the frame number of the detected frame, the percentage of blackness,
2479 the position in the file if known or -1 and the timestamp in seconds.
2481 In order to display the output lines, you need to set the loglevel at
2482 least to the AV_LOG_INFO value.
2484 It accepts the following parameters:
2489 The percentage of the pixels that have to be below the threshold; it defaults to
2492 @item threshold, thresh
2493 The threshold below which a pixel value is considered black; it defaults to
2500 Blend two video frames into each other.
2502 It takes two input streams and outputs one stream, the first input is the
2503 "top" layer and second input is "bottom" layer.
2504 Output terminates when shortest input terminates.
2506 A description of the accepted options follows.
2514 Set blend mode for specific pixel component or all pixel components in case
2515 of @var{all_mode}. Default value is @code{normal}.
2517 Available values for component modes are:
2550 Set blend opacity for specific pixel component or all pixel components in case
2551 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2558 Set blend expression for specific pixel component or all pixel components in case
2559 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2561 The expressions can use the following variables:
2565 The sequential number of the filtered frame, starting from @code{0}.
2569 the coordinates of the current sample
2573 the width and height of currently filtered plane
2577 Width and height scale depending on the currently filtered plane. It is the
2578 ratio between the corresponding luma plane number of pixels and the current
2579 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2580 @code{0.5,0.5} for chroma planes.
2583 Time of the current frame, expressed in seconds.
2586 Value of pixel component at current location for first video frame (top layer).
2589 Value of pixel component at current location for second video frame (bottom layer).
2593 Force termination when the shortest input terminates. Default is @code{0}.
2595 Continue applying the last bottom frame after the end of the stream. A value of
2596 @code{0} disable the filter after the last frame of the bottom layer is reached.
2597 Default is @code{1}.
2600 @subsection Examples
2604 Apply transition from bottom layer to top layer in first 10 seconds:
2606 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2610 Apply 1x1 checkerboard effect:
2612 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2616 Apply uncover left effect:
2618 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2622 Apply uncover down effect:
2624 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2628 Apply uncover up-left effect:
2630 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2636 Apply a boxblur algorithm to the input video.
2638 It accepts the following parameters:
2642 @item luma_radius, lr
2643 @item luma_power, lp
2644 @item chroma_radius, cr
2645 @item chroma_power, cp
2646 @item alpha_radius, ar
2647 @item alpha_power, ap
2651 A description of the accepted options follows.
2654 @item luma_radius, lr
2655 @item chroma_radius, cr
2656 @item alpha_radius, ar
2657 Set an expression for the box radius in pixels used for blurring the
2658 corresponding input plane.
2660 The radius value must be a non-negative number, and must not be
2661 greater than the value of the expression @code{min(w,h)/2} for the
2662 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2665 Default value for @option{luma_radius} is "2". If not specified,
2666 @option{chroma_radius} and @option{alpha_radius} default to the
2667 corresponding value set for @option{luma_radius}.
2669 The expressions can contain the following constants:
2673 The input width and height in pixels.
2677 The input chroma image width and height in pixels.
2681 The horizontal and vertical chroma subsample values. For example, for the
2682 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
2685 @item luma_power, lp
2686 @item chroma_power, cp
2687 @item alpha_power, ap
2688 Specify how many times the boxblur filter is applied to the
2689 corresponding plane.
2691 Default value for @option{luma_power} is 2. If not specified,
2692 @option{chroma_power} and @option{alpha_power} default to the
2693 corresponding value set for @option{luma_power}.
2695 A value of 0 will disable the effect.
2698 @subsection Examples
2702 Apply a boxblur filter with the luma, chroma, and alpha radii
2705 boxblur=luma_radius=2:luma_power=1
2710 Set the luma radius to 2, and alpha and chroma radius to 0:
2712 boxblur=2:1:cr=0:ar=0
2716 Set the luma and chroma radii to a fraction of the video dimension:
2718 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2722 @section colorbalance
2723 Modify intensity of primary colors (red, green and blue) of input frames.
2725 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2726 regions for the red-cyan, green-magenta or blue-yellow balance.
2728 A positive adjustment value shifts the balance towards the primary color, a negative
2729 value towards the complementary color.
2731 The filter accepts the following options:
2737 Adjust red, green and blue shadows (darkest pixels).
2742 Adjust red, green and blue midtones (medium pixels).
2747 Adjust red, green and blue highlights (brightest pixels).
2749 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2752 @subsection Examples
2756 Add red color cast to shadows:
2762 @section colorchannelmixer
2764 Adjust video input frames by re-mixing color channels.
2766 This filter modifies a color channel by adding the values associated to
2767 the other channels of the same pixels. For example if the value to
2768 modify is red, the output value will be:
2770 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2773 The filter accepts the following options:
2780 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2781 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2787 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2788 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2794 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2795 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2801 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2802 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2804 Allowed ranges for options are @code{[-2.0, 2.0]}.
2807 @subsection Examples
2811 Convert source to grayscale:
2813 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2816 Simulate sepia tones:
2818 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
2822 @section colormatrix
2824 Convert color matrix.
2826 The filter accepts the following options:
2831 Specify the source and destination color matrix. Both values must be
2834 The accepted values are:
2850 For example to convert from BT.601 to SMPTE-240M, use the command:
2852 colormatrix=bt601:smpte240m
2857 Copy the input source unchanged to the output. This is mainly useful for
2862 Crop the input video to given dimensions.
2864 It accepts the following parameters:
2868 The width of the output video. It defaults to @code{iw}.
2869 This expression is evaluated only once during the filter
2873 The height of the output video. It defaults to @code{ih}.
2874 This expression is evaluated only once during the filter
2878 The horizontal position, in the input video, of the left edge of the output
2879 video. It defaults to @code{(in_w-out_w)/2}.
2880 This expression is evaluated per-frame.
2883 The vertical position, in the input video, of the top edge of the output video.
2884 It defaults to @code{(in_h-out_h)/2}.
2885 This expression is evaluated per-frame.
2888 If set to 1 will force the output display aspect ratio
2889 to be the same of the input, by changing the output sample aspect
2890 ratio. It defaults to 0.
2893 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
2894 expressions containing the following constants:
2899 The computed values for @var{x} and @var{y}. They are evaluated for
2904 The input width and height.
2908 These are the same as @var{in_w} and @var{in_h}.
2912 The output (cropped) width and height.
2916 These are the same as @var{out_w} and @var{out_h}.
2919 same as @var{iw} / @var{ih}
2922 input sample aspect ratio
2925 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
2929 horizontal and vertical chroma subsample values. For example for the
2930 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2933 The number of the input frame, starting from 0.
2936 the position in the file of the input frame, NAN if unknown
2939 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
2943 The expression for @var{out_w} may depend on the value of @var{out_h},
2944 and the expression for @var{out_h} may depend on @var{out_w}, but they
2945 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
2946 evaluated after @var{out_w} and @var{out_h}.
2948 The @var{x} and @var{y} parameters specify the expressions for the
2949 position of the top-left corner of the output (non-cropped) area. They
2950 are evaluated for each frame. If the evaluated value is not valid, it
2951 is approximated to the nearest valid value.
2953 The expression for @var{x} may depend on @var{y}, and the expression
2954 for @var{y} may depend on @var{x}.
2956 @subsection Examples
2960 Crop area with size 100x100 at position (12,34).
2965 Using named options, the example above becomes:
2967 crop=w=100:h=100:x=12:y=34
2971 Crop the central input area with size 100x100:
2977 Crop the central input area with size 2/3 of the input video:
2979 crop=2/3*in_w:2/3*in_h
2983 Crop the input video central square:
2990 Delimit the rectangle with the top-left corner placed at position
2991 100:100 and the right-bottom corner corresponding to the right-bottom
2992 corner of the input image.
2994 crop=in_w-100:in_h-100:100:100
2998 Crop 10 pixels from the left and right borders, and 20 pixels from
2999 the top and bottom borders
3001 crop=in_w-2*10:in_h-2*20
3005 Keep only the bottom right quarter of the input image:
3007 crop=in_w/2:in_h/2:in_w/2:in_h/2
3011 Crop height for getting Greek harmony:
3013 crop=in_w:1/PHI*in_w
3017 Appply trembling effect:
3019 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)
3023 Apply erratic camera effect depending on timestamp:
3025 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)"
3029 Set x depending on the value of y:
3031 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3037 Auto-detect the crop size.
3039 It calculates the necessary cropping parameters and prints the
3040 recommended parameters via the logging system. The detected dimensions
3041 correspond to the non-black area of the input video.
3043 It accepts the following parameters:
3048 Set higher black value threshold, which can be optionally specified
3049 from nothing (0) to everything (255). An intensity value greater
3050 to the set value is considered non-black. It defaults to 24.
3053 The value which the width/height should be divisible by. It defaults to
3054 16. The offset is automatically adjusted to center the video. Use 2 to
3055 get only even dimensions (needed for 4:2:2 video). 16 is best when
3056 encoding to most video codecs.
3058 @item reset_count, reset
3059 Set the counter that determines after how many frames cropdetect will
3060 reset the previously detected largest video area and start over to
3061 detect the current optimal crop area. Default value is 0.
3063 This can be useful when channel logos distort the video area. 0
3064 indicates 'never reset', and returns the largest area encountered during
3071 Apply color adjustments using curves.
3073 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3074 component (red, green and blue) has its values defined by @var{N} key points
3075 tied from each other using a smooth curve. The x-axis represents the pixel
3076 values from the input frame, and the y-axis the new pixel values to be set for
3079 By default, a component curve is defined by the two points @var{(0;0)} and
3080 @var{(1;1)}. This creates a straight line where each original pixel value is
3081 "adjusted" to its own value, which means no change to the image.
3083 The filter allows you to redefine these two points and add some more. A new
3084 curve (using a natural cubic spline interpolation) will be define to pass
3085 smoothly through all these new coordinates. The new defined points needs to be
3086 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3087 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3088 the vector spaces, the values will be clipped accordingly.
3090 If there is no key point defined in @code{x=0}, the filter will automatically
3091 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3092 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3094 The filter accepts the following options:
3098 Select one of the available color presets. This option can be used in addition
3099 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3100 options takes priority on the preset values.
3101 Available presets are:
3104 @item color_negative
3107 @item increase_contrast
3109 @item linear_contrast
3110 @item medium_contrast
3112 @item strong_contrast
3115 Default is @code{none}.
3117 Set the master key points. These points will define a second pass mapping. It
3118 is sometimes called a "luminance" or "value" mapping. It can be used with
3119 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3120 post-processing LUT.
3122 Set the key points for the red component.
3124 Set the key points for the green component.
3126 Set the key points for the blue component.
3128 Set the key points for all components (not including master).
3129 Can be used in addition to the other key points component
3130 options. In this case, the unset component(s) will fallback on this
3131 @option{all} setting.
3133 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3136 To avoid some filtergraph syntax conflicts, each key points list need to be
3137 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3139 @subsection Examples
3143 Increase slightly the middle level of blue:
3145 curves=blue='0.5/0.58'
3151 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3153 Here we obtain the following coordinates for each components:
3156 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3158 @code{(0;0) (0.50;0.48) (1;1)}
3160 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3164 The previous example can also be achieved with the associated built-in preset:
3166 curves=preset=vintage
3176 Use a Photoshop preset and redefine the points of the green component:
3178 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3184 Denoise frames using 2D DCT (frequency domain filtering).
3186 This filter is not designed for real time and can be extremely slow.
3188 The filter accepts the following options:
3192 Set the noise sigma constant.
3194 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3195 coefficient (absolute value) below this threshold with be dropped.
3197 If you need a more advanced filtering, see @option{expr}.
3199 Default is @code{0}.
3202 Set number overlapping pixels for each block. Each block is of size
3203 @code{16x16}. Since the filter can be slow, you may want to reduce this value,
3204 at the cost of a less effective filter and the risk of various artefacts.
3206 If the overlapping value doesn't allow to process the whole input width or
3207 height, a warning will be displayed and according borders won't be denoised.
3209 Default value is @code{15}.
3212 Set the coefficient factor expression.
3214 For each coefficient of a DCT block, this expression will be evaluated as a
3215 multiplier value for the coefficient.
3217 If this is option is set, the @option{sigma} option will be ignored.
3219 The absolute value of the coefficient can be accessed through the @var{c}
3223 @subsection Examples
3225 Apply a denoise with a @option{sigma} of @code{4.5}:
3230 The same operation can be achieved using the expression system:
3232 dctdnoiz=e='gte(c, 4.5*3)'
3238 Drop duplicated frames at regular intervals.
3240 The filter accepts the following options:
3244 Set the number of frames from which one will be dropped. Setting this to
3245 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3246 Default is @code{5}.
3249 Set the threshold for duplicate detection. If the difference metric for a frame
3250 is less than or equal to this value, then it is declared as duplicate. Default
3254 Set scene change threshold. Default is @code{15}.
3258 Set the size of the x and y-axis blocks used during metric calculations.
3259 Larger blocks give better noise suppression, but also give worse detection of
3260 small movements. Must be a power of two. Default is @code{32}.
3263 Mark main input as a pre-processed input and activate clean source input
3264 stream. This allows the input to be pre-processed with various filters to help
3265 the metrics calculation while keeping the frame selection lossless. When set to
3266 @code{1}, the first stream is for the pre-processed input, and the second
3267 stream is the clean source from where the kept frames are chosen. Default is
3271 Set whether or not chroma is considered in the metric calculations. Default is
3277 Remove judder produced by partially interlaced telecined content.
3279 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3280 source was partially telecined content then the output of @code{pullup,dejudder}
3281 will have a variable frame rate. May change the recorded frame rate of the
3282 container. Aside from that change, this filter will not affect constant frame
3285 The option available in this filter is:
3289 Specify the length of the window over which the judder repeats.
3291 Accepts any interger greater than 1. Useful values are:
3295 If the original was telecined from 24 to 30 fps (Film to NTSC).
3298 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3301 If a mixture of the two.
3304 The default is @samp{4}.
3309 Suppress a TV station logo by a simple interpolation of the surrounding
3310 pixels. Just set a rectangle covering the logo and watch it disappear
3311 (and sometimes something even uglier appear - your mileage may vary).
3313 It accepts the following parameters:
3318 Specify the top left corner coordinates of the logo. They must be
3323 Specify the width and height of the logo to clear. They must be
3327 Specify the thickness of the fuzzy edge of the rectangle (added to
3328 @var{w} and @var{h}). The default value is 4.
3331 When set to 1, a green rectangle is drawn on the screen to simplify
3332 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3333 The default value is 0.
3335 The rectangle is drawn on the outermost pixels which will be (partly)
3336 replaced with interpolated values. The values of the next pixels
3337 immediately outside this rectangle in each direction will be used to
3338 compute the interpolated pixel values inside the rectangle.
3342 @subsection Examples
3346 Set a rectangle covering the area with top left corner coordinates 0,0
3347 and size 100x77, and a band of size 10:
3349 delogo=x=0:y=0:w=100:h=77:band=10
3356 Attempt to fix small changes in horizontal and/or vertical shift. This
3357 filter helps remove camera shake from hand-holding a camera, bumping a
3358 tripod, moving on a vehicle, etc.
3360 The filter accepts the following options:
3368 Specify a rectangular area where to limit the search for motion
3370 If desired the search for motion vectors can be limited to a
3371 rectangular area of the frame defined by its top left corner, width
3372 and height. These parameters have the same meaning as the drawbox
3373 filter which can be used to visualise the position of the bounding
3376 This is useful when simultaneous movement of subjects within the frame
3377 might be confused for camera motion by the motion vector search.
3379 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3380 then the full frame is used. This allows later options to be set
3381 without specifying the bounding box for the motion vector search.
3383 Default - search the whole frame.
3387 Specify the maximum extent of movement in x and y directions in the
3388 range 0-64 pixels. Default 16.
3391 Specify how to generate pixels to fill blanks at the edge of the
3392 frame. Available values are:
3395 Fill zeroes at blank locations
3397 Original image at blank locations
3399 Extruded edge value at blank locations
3401 Mirrored edge at blank locations
3403 Default value is @samp{mirror}.
3406 Specify the blocksize to use for motion search. Range 4-128 pixels,
3410 Specify the contrast threshold for blocks. Only blocks with more than
3411 the specified contrast (difference between darkest and lightest
3412 pixels) will be considered. Range 1-255, default 125.
3415 Specify the search strategy. Available values are:
3418 Set exhaustive search
3420 Set less exhaustive search.
3422 Default value is @samp{exhaustive}.
3425 If set then a detailed log of the motion search is written to the
3429 If set to 1, specify using OpenCL capabilities, only available if
3430 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3436 Draw a colored box on the input image.
3438 It accepts the following parameters:
3443 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3447 The expressions which specify the width and height of the box; if 0 they are interpreted as
3448 the input width and height. It defaults to 0.
3451 Specify the color of the box to write. For the general syntax of this option,
3452 check the "Color" section in the ffmpeg-utils manual. If the special
3453 value @code{invert} is used, the box edge color is the same as the
3454 video with inverted luma.
3457 The expression which sets the thickness of the box edge. Default value is @code{3}.
3459 See below for the list of accepted constants.
3462 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3463 following constants:
3467 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3471 horizontal and vertical chroma subsample values. For example for the
3472 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3476 The input width and height.
3479 The input sample aspect ratio.
3483 The x and y offset coordinates where the box is drawn.
3487 The width and height of the drawn box.
3490 The thickness of the drawn box.
3492 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3493 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3497 @subsection Examples
3501 Draw a black box around the edge of the input image:
3507 Draw a box with color red and an opacity of 50%:
3509 drawbox=10:20:200:60:red@@0.5
3512 The previous example can be specified as:
3514 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3518 Fill the box with pink color:
3520 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3524 Draw a 2-pixel red 2.40:1 mask:
3526 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
3532 Draw a grid on the input image.
3534 It accepts the following parameters:
3539 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3543 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3544 input width and height, respectively, minus @code{thickness}, so image gets
3545 framed. Default to 0.
3548 Specify the color of the grid. For the general syntax of this option,
3549 check the "Color" section in the ffmpeg-utils manual. If the special
3550 value @code{invert} is used, the grid color is the same as the
3551 video with inverted luma.
3554 The expression which sets the thickness of the grid line. Default value is @code{1}.
3556 See below for the list of accepted constants.
3559 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3560 following constants:
3564 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3568 horizontal and vertical chroma subsample values. For example for the
3569 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3573 The input grid cell width and height.
3576 The input sample aspect ratio.
3580 The x and y coordinates of some point of grid intersection (meant to configure offset).
3584 The width and height of the drawn cell.
3587 The thickness of the drawn cell.
3589 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3590 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3594 @subsection Examples
3598 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3600 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3604 Draw a white 3x3 grid with an opacity of 50%:
3606 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3613 Draw a text string or text from a specified file on top of a video, using the
3614 libfreetype library.
3616 To enable compilation of this filter, you need to configure FFmpeg with
3617 @code{--enable-libfreetype}.
3618 To enable default font fallback and the @var{font} option you need to
3619 configure FFmpeg with @code{--enable-libfontconfig}.
3623 It accepts the following parameters:
3628 Used to draw a box around text using the background color.
3629 The value must be either 1 (enable) or 0 (disable).
3630 The default value of @var{box} is 0.
3633 The color to be used for drawing box around text. For the syntax of this
3634 option, check the "Color" section in the ffmpeg-utils manual.
3636 The default value of @var{boxcolor} is "white".
3639 Set the width of the border to be drawn around the text using @var{bordercolor}.
3640 The default value of @var{borderw} is 0.
3643 Set the color to be used for drawing border around text. For the syntax of this
3644 option, check the "Color" section in the ffmpeg-utils manual.
3646 The default value of @var{bordercolor} is "black".
3649 Select how the @var{text} is expanded. Can be either @code{none},
3650 @code{strftime} (deprecated) or
3651 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3655 If true, check and fix text coords to avoid clipping.
3658 The color to be used for drawing fonts. For the syntax of this option, check
3659 the "Color" section in the ffmpeg-utils manual.
3661 The default value of @var{fontcolor} is "black".
3664 The font family to be used for drawing text. By default Sans.
3667 The font file to be used for drawing text. The path must be included.
3668 This parameter is mandatory if the fontconfig support is disabled.
3671 The font size to be used for drawing text.
3672 The default value of @var{fontsize} is 16.
3675 The flags to be used for loading the fonts.
3677 The flags map the corresponding flags supported by libfreetype, and are
3678 a combination of the following values:
3685 @item vertical_layout
3686 @item force_autohint
3689 @item ignore_global_advance_width
3691 @item ignore_transform
3697 Default value is "default".
3699 For more information consult the documentation for the FT_LOAD_*
3703 The color to be used for drawing a shadow behind the drawn text. For the
3704 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3706 The default value of @var{shadowcolor} is "black".
3710 The x and y offsets for the text shadow position with respect to the
3711 position of the text. They can be either positive or negative
3712 values. The default value for both is "0".
3715 The starting frame number for the n/frame_num variable. The default value
3719 The size in number of spaces to use for rendering the tab.
3723 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3724 format. It can be used with or without text parameter. @var{timecode_rate}
3725 option must be specified.
3727 @item timecode_rate, rate, r
3728 Set the timecode frame rate (timecode only).
3731 The text string to be drawn. The text must be a sequence of UTF-8
3733 This parameter is mandatory if no file is specified with the parameter
3737 A text file containing text to be drawn. The text must be a sequence
3738 of UTF-8 encoded characters.
3740 This parameter is mandatory if no text string is specified with the
3741 parameter @var{text}.
3743 If both @var{text} and @var{textfile} are specified, an error is thrown.
3746 If set to 1, the @var{textfile} will be reloaded before each frame.
3747 Be sure to update it atomically, or it may be read partially, or even fail.
3751 The expressions which specify the offsets where text will be drawn
3752 within the video frame. They are relative to the top/left border of the
3755 The default value of @var{x} and @var{y} is "0".
3757 See below for the list of accepted constants and functions.
3760 The parameters for @var{x} and @var{y} are expressions containing the
3761 following constants and functions:
3765 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3769 horizontal and vertical chroma subsample values. For example for the
3770 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3773 the height of each text line
3781 @item max_glyph_a, ascent
3782 the maximum distance from the baseline to the highest/upper grid
3783 coordinate used to place a glyph outline point, for all the rendered
3785 It is a positive value, due to the grid's orientation with the Y axis
3788 @item max_glyph_d, descent
3789 the maximum distance from the baseline to the lowest grid coordinate
3790 used to place a glyph outline point, for all the rendered glyphs.
3791 This is a negative value, due to the grid's orientation, with the Y axis
3795 maximum glyph height, that is the maximum height for all the glyphs
3796 contained in the rendered text, it is equivalent to @var{ascent} -
3800 maximum glyph width, that is the maximum width for all the glyphs
3801 contained in the rendered text
3804 the number of input frame, starting from 0
3806 @item rand(min, max)
3807 return a random number included between @var{min} and @var{max}
3810 The input sample aspect ratio.
3813 timestamp expressed in seconds, NAN if the input timestamp is unknown
3816 the height of the rendered text
3819 the width of the rendered text
3823 the x and y offset coordinates where the text is drawn.
3825 These parameters allow the @var{x} and @var{y} expressions to refer
3826 each other, so you can for example specify @code{y=x/dar}.
3829 @anchor{drawtext_expansion}
3830 @subsection Text expansion
3832 If @option{expansion} is set to @code{strftime},
3833 the filter recognizes strftime() sequences in the provided text and
3834 expands them accordingly. Check the documentation of strftime(). This
3835 feature is deprecated.
3837 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3839 If @option{expansion} is set to @code{normal} (which is the default),
3840 the following expansion mechanism is used.
3842 The backslash character '\', followed by any character, always expands to
3843 the second character.
3845 Sequence of the form @code{%@{...@}} are expanded. The text between the
3846 braces is a function name, possibly followed by arguments separated by ':'.
3847 If the arguments contain special characters or delimiters (':' or '@}'),
3848 they should be escaped.
3850 Note that they probably must also be escaped as the value for the
3851 @option{text} option in the filter argument string and as the filter
3852 argument in the filtergraph description, and possibly also for the shell,
3853 that makes up to four levels of escaping; using a text file avoids these
3856 The following functions are available:
3861 The expression evaluation result.
3863 It must take one argument specifying the expression to be evaluated,
3864 which accepts the same constants and functions as the @var{x} and
3865 @var{y} values. Note that not all constants should be used, for
3866 example the text size is not known when evaluating the expression, so
3867 the constants @var{text_w} and @var{text_h} will have an undefined
3871 The time at which the filter is running, expressed in UTC.
3872 It can accept an argument: a strftime() format string.
3875 The time at which the filter is running, expressed in the local time zone.
3876 It can accept an argument: a strftime() format string.
3879 Frame metadata. It must take one argument specifying metadata key.
3882 The frame number, starting from 0.
3885 A 1 character description of the current picture type.
3888 The timestamp of the current frame.
3889 It can take up to two arguments.
3891 The first argument is the format of the timestamp; it defaults to @code{flt}
3892 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
3893 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
3895 The second argument is an offset added to the timestamp.
3899 @subsection Examples
3903 Draw "Test Text" with font FreeSerif, using the default values for the
3904 optional parameters.
3907 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
3911 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
3912 and y=50 (counting from the top-left corner of the screen), text is
3913 yellow with a red box around it. Both the text and the box have an
3917 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
3918 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
3921 Note that the double quotes are not necessary if spaces are not used
3922 within the parameter list.
3925 Show the text at the center of the video frame:
3927 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
3931 Show a text line sliding from right to left in the last row of the video
3932 frame. The file @file{LONG_LINE} is assumed to contain a single line
3935 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
3939 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
3941 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
3945 Draw a single green letter "g", at the center of the input video.
3946 The glyph baseline is placed at half screen height.
3948 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
3952 Show text for 1 second every 3 seconds:
3954 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
3958 Use fontconfig to set the font. Note that the colons need to be escaped.
3960 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
3964 Print the date of a real-time encoding (see strftime(3)):
3966 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
3971 For more information about libfreetype, check:
3972 @url{http://www.freetype.org/}.
3974 For more information about fontconfig, check:
3975 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
3979 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
3981 The filter accepts the following options:
3986 Set low and high threshold values used by the Canny thresholding
3989 The high threshold selects the "strong" edge pixels, which are then
3990 connected through 8-connectivity with the "weak" edge pixels selected
3991 by the low threshold.
3993 @var{low} and @var{high} threshold values must be chosen in the range
3994 [0,1], and @var{low} should be lesser or equal to @var{high}.
3996 Default value for @var{low} is @code{20/255}, and default value for @var{high}
4000 Define the drawing mode.
4004 Draw white/gray wires on black background.
4007 Mix the colors to create a paint/cartoon effect.
4010 Default value is @var{wires}.
4013 @subsection Examples
4017 Standard edge detection with custom values for the hysteresis thresholding:
4019 edgedetect=low=0.1:high=0.4
4023 Painting effect without thresholding:
4025 edgedetect=mode=colormix:high=0
4029 @section extractplanes
4031 Extract color channel components from input video stream into
4032 separate grayscale video streams.
4034 The filter accepts the following option:
4038 Set plane(s) to extract.
4040 Available values for planes are:
4051 Choosing planes not available in the input will result in an error.
4052 That means you cannot select @code{r}, @code{g}, @code{b} planes
4053 with @code{y}, @code{u}, @code{v} planes at same time.
4056 @subsection Examples
4060 Extract luma, u and v color channel component from input video frame
4061 into 3 grayscale outputs:
4063 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
4069 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4071 For each input image, the filter will compute the optimal mapping from
4072 the input to the output given the codebook length, that is the number
4073 of distinct output colors.
4075 This filter accepts the following options.
4078 @item codebook_length, l
4079 Set codebook length. The value must be a positive integer, and
4080 represents the number of distinct output colors. Default value is 256.
4083 Set the maximum number of iterations to apply for computing the optimal
4084 mapping. The higher the value the better the result and the higher the
4085 computation time. Default value is 1.
4088 Set a random seed, must be an integer included between 0 and
4089 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4090 will try to use a good random seed on a best effort basis.
4095 Apply a fade-in/out effect to the input video.
4097 It accepts the following parameters:
4101 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4103 Default is @code{in}.
4105 @item start_frame, s
4106 Specify the number of the frame to start applying the fade
4107 effect at. Default is 0.
4110 The number of frames that the fade effect lasts. At the end of the
4111 fade-in effect, the output video will have the same intensity as the input video.
4112 At the end of the fade-out transition, the output video will be filled with the
4113 selected @option{color}.
4117 If set to 1, fade only alpha channel, if one exists on the input.
4120 @item start_time, st
4121 Specify the timestamp (in seconds) of the frame to start to apply the fade
4122 effect. If both start_frame and start_time are specified, the fade will start at
4123 whichever comes last. Default is 0.
4126 The number of seconds for which the fade effect has to last. At the end of the
4127 fade-in effect the output video will have the same intensity as the input video,
4128 at the end of the fade-out transition the output video will be filled with the
4129 selected @option{color}.
4130 If both duration and nb_frames are specified, duration is used. Default is 0.
4133 Specify the color of the fade. Default is "black".
4136 @subsection Examples
4140 Fade in the first 30 frames of video:
4145 The command above is equivalent to:
4151 Fade out the last 45 frames of a 200-frame video:
4154 fade=type=out:start_frame=155:nb_frames=45
4158 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4160 fade=in:0:25, fade=out:975:25
4164 Make the first 5 frames yellow, then fade in from frame 5-24:
4166 fade=in:5:20:color=yellow
4170 Fade in alpha over first 25 frames of video:
4172 fade=in:0:25:alpha=1
4176 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4178 fade=t=in:st=5.5:d=0.5
4185 Extract a single field from an interlaced image using stride
4186 arithmetic to avoid wasting CPU time. The output frames are marked as
4189 The filter accepts the following options:
4193 Specify whether to extract the top (if the value is @code{0} or
4194 @code{top}) or the bottom field (if the value is @code{1} or
4200 Field matching filter for inverse telecine. It is meant to reconstruct the
4201 progressive frames from a telecined stream. The filter does not drop duplicated
4202 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4203 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4205 The separation of the field matching and the decimation is notably motivated by
4206 the possibility of inserting a de-interlacing filter fallback between the two.
4207 If the source has mixed telecined and real interlaced content,
4208 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4209 But these remaining combed frames will be marked as interlaced, and thus can be
4210 de-interlaced by a later filter such as @ref{yadif} before decimation.
4212 In addition to the various configuration options, @code{fieldmatch} can take an
4213 optional second stream, activated through the @option{ppsrc} option. If
4214 enabled, the frames reconstruction will be based on the fields and frames from
4215 this second stream. This allows the first input to be pre-processed in order to
4216 help the various algorithms of the filter, while keeping the output lossless
4217 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4218 or brightness/contrast adjustments can help.
4220 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4221 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4222 which @code{fieldmatch} is based on. While the semantic and usage are very
4223 close, some behaviour and options names can differ.
4225 The filter accepts the following options:
4229 Specify the assumed field order of the input stream. Available values are:
4233 Auto detect parity (use FFmpeg's internal parity value).
4235 Assume bottom field first.
4237 Assume top field first.
4240 Note that it is sometimes recommended not to trust the parity announced by the
4243 Default value is @var{auto}.
4246 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4247 sense that it won't risk creating jerkiness due to duplicate frames when
4248 possible, but if there are bad edits or blended fields it will end up
4249 outputting combed frames when a good match might actually exist. On the other
4250 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4251 but will almost always find a good frame if there is one. The other values are
4252 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4253 jerkiness and creating duplicate frames versus finding good matches in sections
4254 with bad edits, orphaned fields, blended fields, etc.
4256 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4258 Available values are:
4262 2-way matching (p/c)
4264 2-way matching, and trying 3rd match if still combed (p/c + n)
4266 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4268 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4269 still combed (p/c + n + u/b)
4271 3-way matching (p/c/n)
4273 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4274 detected as combed (p/c/n + u/b)
4277 The parenthesis at the end indicate the matches that would be used for that
4278 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4281 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4284 Default value is @var{pc_n}.
4287 Mark the main input stream as a pre-processed input, and enable the secondary
4288 input stream as the clean source to pick the fields from. See the filter
4289 introduction for more details. It is similar to the @option{clip2} feature from
4292 Default value is @code{0} (disabled).
4295 Set the field to match from. It is recommended to set this to the same value as
4296 @option{order} unless you experience matching failures with that setting. In
4297 certain circumstances changing the field that is used to match from can have a
4298 large impact on matching performance. Available values are:
4302 Automatic (same value as @option{order}).
4304 Match from the bottom field.
4306 Match from the top field.
4309 Default value is @var{auto}.
4312 Set whether or not chroma is included during the match comparisons. In most
4313 cases it is recommended to leave this enabled. You should set this to @code{0}
4314 only if your clip has bad chroma problems such as heavy rainbowing or other
4315 artifacts. Setting this to @code{0} could also be used to speed things up at
4316 the cost of some accuracy.
4318 Default value is @code{1}.
4322 These define an exclusion band which excludes the lines between @option{y0} and
4323 @option{y1} from being included in the field matching decision. An exclusion
4324 band can be used to ignore subtitles, a logo, or other things that may
4325 interfere with the matching. @option{y0} sets the starting scan line and
4326 @option{y1} sets the ending line; all lines in between @option{y0} and
4327 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4328 @option{y0} and @option{y1} to the same value will disable the feature.
4329 @option{y0} and @option{y1} defaults to @code{0}.
4332 Set the scene change detection threshold as a percentage of maximum change on
4333 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4334 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4335 @option{scthresh} is @code{[0.0, 100.0]}.
4337 Default value is @code{12.0}.
4340 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4341 account the combed scores of matches when deciding what match to use as the
4342 final match. Available values are:
4346 No final matching based on combed scores.
4348 Combed scores are only used when a scene change is detected.
4350 Use combed scores all the time.
4353 Default is @var{sc}.
4356 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4357 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4358 Available values are:
4362 No forced calculation.
4364 Force p/c/n calculations.
4366 Force p/c/n/u/b calculations.
4369 Default value is @var{none}.
4372 This is the area combing threshold used for combed frame detection. This
4373 essentially controls how "strong" or "visible" combing must be to be detected.
4374 Larger values mean combing must be more visible and smaller values mean combing
4375 can be less visible or strong and still be detected. Valid settings are from
4376 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4377 be detected as combed). This is basically a pixel difference value. A good
4378 range is @code{[8, 12]}.
4380 Default value is @code{9}.
4383 Sets whether or not chroma is considered in the combed frame decision. Only
4384 disable this if your source has chroma problems (rainbowing, etc.) that are
4385 causing problems for the combed frame detection with chroma enabled. Actually,
4386 using @option{chroma}=@var{0} is usually more reliable, except for the case
4387 where there is chroma only combing in the source.
4389 Default value is @code{0}.
4393 Respectively set the x-axis and y-axis size of the window used during combed
4394 frame detection. This has to do with the size of the area in which
4395 @option{combpel} pixels are required to be detected as combed for a frame to be
4396 declared combed. See the @option{combpel} parameter description for more info.
4397 Possible values are any number that is a power of 2 starting at 4 and going up
4400 Default value is @code{16}.
4403 The number of combed pixels inside any of the @option{blocky} by
4404 @option{blockx} size blocks on the frame for the frame to be detected as
4405 combed. While @option{cthresh} controls how "visible" the combing must be, this
4406 setting controls "how much" combing there must be in any localized area (a
4407 window defined by the @option{blockx} and @option{blocky} settings) on the
4408 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4409 which point no frames will ever be detected as combed). This setting is known
4410 as @option{MI} in TFM/VFM vocabulary.
4412 Default value is @code{80}.
4415 @anchor{p/c/n/u/b meaning}
4416 @subsection p/c/n/u/b meaning
4418 @subsubsection p/c/n
4420 We assume the following telecined stream:
4423 Top fields: 1 2 2 3 4
4424 Bottom fields: 1 2 3 4 4
4427 The numbers correspond to the progressive frame the fields relate to. Here, the
4428 first two frames are progressive, the 3rd and 4th are combed, and so on.
4430 When @code{fieldmatch} is configured to run a matching from bottom
4431 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4436 B 1 2 3 4 4 <-- matching reference
4445 As a result of the field matching, we can see that some frames get duplicated.
4446 To perform a complete inverse telecine, you need to rely on a decimation filter
4447 after this operation. See for instance the @ref{decimate} filter.
4449 The same operation now matching from top fields (@option{field}=@var{top})
4454 T 1 2 2 3 4 <-- matching reference
4464 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4465 basically, they refer to the frame and field of the opposite parity:
4468 @item @var{p} matches the field of the opposite parity in the previous frame
4469 @item @var{c} matches the field of the opposite parity in the current frame
4470 @item @var{n} matches the field of the opposite parity in the next frame
4475 The @var{u} and @var{b} matching are a bit special in the sense that they match
4476 from the opposite parity flag. In the following examples, we assume that we are
4477 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4478 'x' is placed above and below each matched fields.
4480 With bottom matching (@option{field}=@var{bottom}):
4485 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4486 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4494 With top matching (@option{field}=@var{top}):
4499 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4500 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4508 @subsection Examples
4510 Simple IVTC of a top field first telecined stream:
4512 fieldmatch=order=tff:combmatch=none, decimate
4515 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4517 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4522 Transform the field order of the input video.
4524 It accepts the following parameters:
4529 The output field order. Valid values are @var{tff} for top field first or @var{bff}
4530 for bottom field first.
4533 The default value is @samp{tff}.
4535 The transformation is done by shifting the picture content up or down
4536 by one line, and filling the remaining line with appropriate picture content.
4537 This method is consistent with most broadcast field order converters.
4539 If the input video is not flagged as being interlaced, or it is already
4540 flagged as being of the required output field order, then this filter does
4541 not alter the incoming video.
4543 It is very useful when converting to or from PAL DV material,
4544 which is bottom field first.
4548 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4553 Buffer input images and send them when they are requested.
4555 It is mainly useful when auto-inserted by the libavfilter
4558 It does not take parameters.
4563 Convert the input video to one of the specified pixel formats.
4564 Libavfilter will try to pick one that is suitable as input to
4567 It accepts the following parameters:
4571 A '|'-separated list of pixel format names, such as
4572 "pix_fmts=yuv420p|monow|rgb24".
4576 @subsection Examples
4580 Convert the input video to the @var{yuv420p} format
4582 format=pix_fmts=yuv420p
4585 Convert the input video to any of the formats in the list
4587 format=pix_fmts=yuv420p|yuv444p|yuv410p
4594 Convert the video to specified constant frame rate by duplicating or dropping
4595 frames as necessary.
4597 It accepts the following parameters:
4601 The desired output frame rate. The default is @code{25}.
4606 Possible values are:
4609 zero round towards 0
4613 round towards -infinity
4615 round towards +infinity
4619 The default is @code{near}.
4622 Assume the first PTS should be the given value, in seconds. This allows for
4623 padding/trimming at the start of stream. By default, no assumption is made
4624 about the first frame's expected PTS, so no padding or trimming is done.
4625 For example, this could be set to 0 to pad the beginning with duplicates of
4626 the first frame if a video stream starts after the audio stream or to trim any
4627 frames with a negative PTS.
4631 Alternatively, the options can be specified as a flat string:
4632 @var{fps}[:@var{round}].
4634 See also the @ref{setpts} filter.
4636 @subsection Examples
4640 A typical usage in order to set the fps to 25:
4646 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4648 fps=fps=film:round=near
4654 Pack two different video streams into a stereoscopic video, setting proper
4655 metadata on supported codecs. The two views should have the same size and
4656 framerate and processing will stop when the shorter video ends. Please note
4657 that you may conveniently adjust view properties with the @ref{scale} and
4660 It accepts the following parameters:
4664 The desired packing format. Supported values are:
4669 The views are next to each other (default).
4672 The views are on top of each other.
4675 The views are packed by line.
4678 The views are packed by column.
4681 The views are temporally interleaved.
4690 # Convert left and right views into a frame-sequential video
4691 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
4693 # Convert views into a side-by-side video with the same output resolution as the input
4694 ffmpeg -i LEFT -i RIGHT -filter_complex [0:v]scale=w=iw/2[left],[1:v]scale=w=iw/2[right],[left][right]framepack=sbs OUTPUT
4699 Select one frame every N-th frame.
4701 This filter accepts the following option:
4704 Select frame after every @code{step} frames.
4705 Allowed values are positive integers higher than 0. Default value is @code{1}.
4711 Apply a frei0r effect to the input video.
4713 To enable the compilation of this filter, you need to install the frei0r
4714 header and configure FFmpeg with @code{--enable-frei0r}.
4716 It accepts the following parameters:
4721 The name of the frei0r effect to load. If the environment variable
4722 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
4723 directories specified by the colon-separated list in @env{FREIOR_PATH}.
4724 Otherwise, the standard frei0r paths are searched, in this order:
4725 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
4726 @file{/usr/lib/frei0r-1/}.
4729 A '|'-separated list of parameters to pass to the frei0r effect.
4733 A frei0r effect parameter can be a boolean (its value is either
4734 "y" or "n"), a double, a color (specified as
4735 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
4736 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
4737 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
4738 @var{X} and @var{Y} are floating point numbers) and/or a string.
4740 The number and types of parameters depend on the loaded effect. If an
4741 effect parameter is not specified, the default value is set.
4743 @subsection Examples
4747 Apply the distort0r effect, setting the first two double parameters:
4749 frei0r=filter_name=distort0r:filter_params=0.5|0.01
4753 Apply the colordistance effect, taking a color as the first parameter:
4755 frei0r=colordistance:0.2/0.3/0.4
4756 frei0r=colordistance:violet
4757 frei0r=colordistance:0x112233
4761 Apply the perspective effect, specifying the top left and top right image
4764 frei0r=perspective:0.2/0.2|0.8/0.2
4768 For more information, see
4769 @url{http://frei0r.dyne.org}
4773 The filter accepts the following options:
4777 Set the luminance expression.
4779 Set the chrominance blue expression.
4781 Set the chrominance red expression.
4783 Set the alpha expression.
4785 Set the red expression.
4787 Set the green expression.
4789 Set the blue expression.
4792 The colorspace is selected according to the specified options. If one
4793 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4794 options is specified, the filter will automatically select a YCbCr
4795 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4796 @option{blue_expr} options is specified, it will select an RGB
4799 If one of the chrominance expression is not defined, it falls back on the other
4800 one. If no alpha expression is specified it will evaluate to opaque value.
4801 If none of chrominance expressions are specified, they will evaluate
4802 to the luminance expression.
4804 The expressions can use the following variables and functions:
4808 The sequential number of the filtered frame, starting from @code{0}.
4812 The coordinates of the current sample.
4816 The width and height of the image.
4820 Width and height scale depending on the currently filtered plane. It is the
4821 ratio between the corresponding luma plane number of pixels and the current
4822 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4823 @code{0.5,0.5} for chroma planes.
4826 Time of the current frame, expressed in seconds.
4829 Return the value of the pixel at location (@var{x},@var{y}) of the current
4833 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
4837 Return the value of the pixel at location (@var{x},@var{y}) of the
4838 blue-difference chroma plane. Return 0 if there is no such plane.
4841 Return the value of the pixel at location (@var{x},@var{y}) of the
4842 red-difference chroma plane. Return 0 if there is no such plane.
4847 Return the value of the pixel at location (@var{x},@var{y}) of the
4848 red/green/blue component. Return 0 if there is no such component.
4851 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
4852 plane. Return 0 if there is no such plane.
4855 For functions, if @var{x} and @var{y} are outside the area, the value will be
4856 automatically clipped to the closer edge.
4858 @subsection Examples
4862 Flip the image horizontally:
4868 Generate a bidimensional sine wave, with angle @code{PI/3} and a
4869 wavelength of 100 pixels:
4871 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
4875 Generate a fancy enigmatic moving light:
4877 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
4881 Generate a quick emboss effect:
4883 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
4887 Modify RGB components depending on pixel position:
4889 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
4895 Fix the banding artifacts that are sometimes introduced into nearly flat
4896 regions by truncation to 8bit color depth.
4897 Interpolate the gradients that should go where the bands are, and
4900 It is designed for playback only. Do not use it prior to
4901 lossy compression, because compression tends to lose the dither and
4902 bring back the bands.
4904 It accepts the following parameters:
4909 The maximum amount by which the filter will change any one pixel. This is also
4910 the threshold for detecting nearly flat regions. Acceptable values range from
4911 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
4915 The neighborhood to fit the gradient to. A larger radius makes for smoother
4916 gradients, but also prevents the filter from modifying the pixels near detailed
4917 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
4918 values will be clipped to the valid range.
4922 Alternatively, the options can be specified as a flat string:
4923 @var{strength}[:@var{radius}]
4925 @subsection Examples
4929 Apply the filter with a @code{3.5} strength and radius of @code{8}:
4935 Specify radius, omitting the strength (which will fall-back to the default
4946 Apply a Hald CLUT to a video stream.
4948 First input is the video stream to process, and second one is the Hald CLUT.
4949 The Hald CLUT input can be a simple picture or a complete video stream.
4951 The filter accepts the following options:
4955 Force termination when the shortest input terminates. Default is @code{0}.
4957 Continue applying the last CLUT after the end of the stream. A value of
4958 @code{0} disable the filter after the last frame of the CLUT is reached.
4959 Default is @code{1}.
4962 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
4963 filters share the same internals).
4965 More information about the Hald CLUT can be found on Eskil Steenberg's website
4966 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
4968 @subsection Workflow examples
4970 @subsubsection Hald CLUT video stream
4972 Generate an identity Hald CLUT stream altered with various effects:
4974 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
4977 Note: make sure you use a lossless codec.
4979 Then use it with @code{haldclut} to apply it on some random stream:
4981 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
4984 The Hald CLUT will be applied to the 10 first seconds (duration of
4985 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
4986 to the remaining frames of the @code{mandelbrot} stream.
4988 @subsubsection Hald CLUT with preview
4990 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
4991 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
4992 biggest possible square starting at the top left of the picture. The remaining
4993 padding pixels (bottom or right) will be ignored. This area can be used to add
4994 a preview of the Hald CLUT.
4996 Typically, the following generated Hald CLUT will be supported by the
4997 @code{haldclut} filter:
5000 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
5001 pad=iw+320 [padded_clut];
5002 smptebars=s=320x256, split [a][b];
5003 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
5004 [main][b] overlay=W-320" -frames:v 1 clut.png
5007 It contains the original and a preview of the effect of the CLUT: SMPTE color
5008 bars are displayed on the right-top, and below the same color bars processed by
5011 Then, the effect of this Hald CLUT can be visualized with:
5013 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
5018 Flip the input video horizontally.
5020 For example, to horizontally flip the input video with @command{ffmpeg}:
5022 ffmpeg -i in.avi -vf "hflip" out.avi
5026 This filter applies a global color histogram equalization on a
5029 It can be used to correct video that has a compressed range of pixel
5030 intensities. The filter redistributes the pixel intensities to
5031 equalize their distribution across the intensity range. It may be
5032 viewed as an "automatically adjusting contrast filter". This filter is
5033 useful only for correcting degraded or poorly captured source
5036 The filter accepts the following options:
5040 Determine the amount of equalization to be applied. As the strength
5041 is reduced, the distribution of pixel intensities more-and-more
5042 approaches that of the input frame. The value must be a float number
5043 in the range [0,1] and defaults to 0.200.
5046 Set the maximum intensity that can generated and scale the output
5047 values appropriately. The strength should be set as desired and then
5048 the intensity can be limited if needed to avoid washing-out. The value
5049 must be a float number in the range [0,1] and defaults to 0.210.
5052 Set the antibanding level. If enabled the filter will randomly vary
5053 the luminance of output pixels by a small amount to avoid banding of
5054 the histogram. Possible values are @code{none}, @code{weak} or
5055 @code{strong}. It defaults to @code{none}.
5060 Compute and draw a color distribution histogram for the input video.
5062 The computed histogram is a representation of the color component
5063 distribution in an image.
5065 The filter accepts the following options:
5071 It accepts the following values:
5074 Standard histogram that displays the color components distribution in an
5075 image. Displays color graph for each color component. Shows distribution of
5076 the Y, U, V, A or R, G, B components, depending on input format, in the
5077 current frame. Below each graph a color component scale meter is shown.
5080 Displays chroma values (U/V color placement) in a two dimensional
5081 graph (which is called a vectorscope). The brighter a pixel in the
5082 vectorscope, the more pixels of the input frame correspond to that pixel
5083 (i.e., more pixels have this chroma value). The V component is displayed on
5084 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5085 side being V = 255. The U component is displayed on the vertical (Y) axis,
5086 with the top representing U = 0 and the bottom representing U = 255.
5088 The position of a white pixel in the graph corresponds to the chroma value of
5089 a pixel of the input clip. The graph can therefore be used to read the hue
5090 (color flavor) and the saturation (the dominance of the hue in the color). As
5091 the hue of a color changes, it moves around the square. At the center of the
5092 square the saturation is zero, which means that the corresponding pixel has no
5093 color. If the amount of a specific color is increased (while leaving the other
5094 colors unchanged) the saturation increases, and the indicator moves towards
5095 the edge of the square.
5098 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5102 Per row/column color component graph. In row mode, the graph on the left side
5103 represents color component value 0 and the right side represents value = 255.
5104 In column mode, the top side represents color component value = 0 and bottom
5105 side represents value = 255.
5107 Default value is @code{levels}.
5110 Set height of level in @code{levels}. Default value is @code{200}.
5111 Allowed range is [50, 2048].
5114 Set height of color scale in @code{levels}. Default value is @code{12}.
5115 Allowed range is [0, 40].
5118 Set step for @code{waveform} mode. Smaller values are useful to find out how
5119 many values of the same luminance are distributed across input rows/columns.
5120 Default value is @code{10}. Allowed range is [1, 255].
5123 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5124 Default is @code{row}.
5126 @item waveform_mirror
5127 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5128 means mirrored. In mirrored mode, higher values will be represented on the left
5129 side for @code{row} mode and at the top for @code{column} mode. Default is
5130 @code{0} (unmirrored).
5133 Set display mode for @code{waveform} and @code{levels}.
5134 It accepts the following values:
5137 Display separate graph for the color components side by side in
5138 @code{row} waveform mode or one below the other in @code{column} waveform mode
5139 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5140 per color component graphs are placed below each other.
5142 Using this display mode in @code{waveform} histogram mode makes it easy to
5143 spot color casts in the highlights and shadows of an image, by comparing the
5144 contours of the top and the bottom graphs of each waveform. Since whites,
5145 grays, and blacks are characterized by exactly equal amounts of red, green,
5146 and blue, neutral areas of the picture should display three waveforms of
5147 roughly equal width/height. If not, the correction is easy to perform by
5148 making level adjustments the three waveforms.
5151 Presents information identical to that in the @code{parade}, except
5152 that the graphs representing color components are superimposed directly
5155 This display mode in @code{waveform} histogram mode makes it easier to spot
5156 relative differences or similarities in overlapping areas of the color
5157 components that are supposed to be identical, such as neutral whites, grays,
5160 Default is @code{parade}.
5163 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5164 Default is @code{linear}.
5167 @subsection Examples
5172 Calculate and draw histogram:
5174 ffplay -i input -vf histogram
5182 This is a high precision/quality 3d denoise filter. It aims to reduce
5183 image noise, producing smooth images and making still images really
5184 still. It should enhance compressibility.
5186 It accepts the following optional parameters:
5190 A non-negative floating point number which specifies spatial luma strength.
5193 @item chroma_spatial
5194 A non-negative floating point number which specifies spatial chroma strength.
5195 It defaults to 3.0*@var{luma_spatial}/4.0.
5198 A floating point number which specifies luma temporal strength. It defaults to
5199 6.0*@var{luma_spatial}/4.0.
5202 A floating point number which specifies chroma temporal strength. It defaults to
5203 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5208 Modify the hue and/or the saturation of the input.
5210 It accepts the following parameters:
5214 Specify the hue angle as a number of degrees. It accepts an expression,
5215 and defaults to "0".
5218 Specify the saturation in the [-10,10] range. It accepts an expression and
5222 Specify the hue angle as a number of radians. It accepts an
5223 expression, and defaults to "0".
5226 Specify the brightness in the [-10,10] range. It accepts an expression and
5230 @option{h} and @option{H} are mutually exclusive, and can't be
5231 specified at the same time.
5233 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5234 expressions containing the following constants:
5238 frame count of the input frame starting from 0
5241 presentation timestamp of the input frame expressed in time base units
5244 frame rate of the input video, NAN if the input frame rate is unknown
5247 timestamp expressed in seconds, NAN if the input timestamp is unknown
5250 time base of the input video
5253 @subsection Examples
5257 Set the hue to 90 degrees and the saturation to 1.0:
5263 Same command but expressing the hue in radians:
5269 Rotate hue and make the saturation swing between 0
5270 and 2 over a period of 1 second:
5272 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5276 Apply a 3 seconds saturation fade-in effect starting at 0:
5281 The general fade-in expression can be written as:
5283 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5287 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5289 hue="s=max(0\, min(1\, (8-t)/3))"
5292 The general fade-out expression can be written as:
5294 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5299 @subsection Commands
5301 This filter supports the following commands:
5307 Modify the hue and/or the saturation and/or brightness of the input video.
5308 The command accepts the same syntax of the corresponding option.
5310 If the specified expression is not valid, it is kept at its current
5316 Detect video interlacing type.
5318 This filter tries to detect if the input is interlaced or progressive,
5319 top or bottom field first.
5321 The filter accepts the following options:
5325 Set interlacing threshold.
5327 Set progressive threshold.
5332 Deinterleave or interleave fields.
5334 This filter allows one to process interlaced images fields without
5335 deinterlacing them. Deinterleaving splits the input frame into 2
5336 fields (so called half pictures). Odd lines are moved to the top
5337 half of the output image, even lines to the bottom half.
5338 You can process (filter) them independently and then re-interleave them.
5340 The filter accepts the following options:
5344 @item chroma_mode, c
5346 Available values for @var{luma_mode}, @var{chroma_mode} and
5347 @var{alpha_mode} are:
5353 @item deinterleave, d
5354 Deinterleave fields, placing one above the other.
5357 Interleave fields. Reverse the effect of deinterleaving.
5359 Default value is @code{none}.
5362 @item chroma_swap, cs
5363 @item alpha_swap, as
5364 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5369 Simple interlacing filter from progressive contents. This interleaves upper (or
5370 lower) lines from odd frames with lower (or upper) lines from even frames,
5371 halving the frame rate and preserving image height. A vertical lowpass filter
5372 is always applied in order to avoid twitter effects and reduce moiré patterns.
5375 Original Original New Frame
5376 Frame 'j' Frame 'j+1' (tff)
5377 ========== =========== ==================
5378 Line 0 --------------------> Frame 'j' Line 0
5379 Line 1 Line 1 ----> Frame 'j+1' Line 1
5380 Line 2 ---------------------> Frame 'j' Line 2
5381 Line 3 Line 3 ----> Frame 'j+1' Line 3
5383 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5386 It accepts the following optional parameters:
5390 This determines whether the interlaced frame is taken from the even
5391 (tff - default) or odd (bff) lines of the progressive frame.
5396 Deinterlace input video by applying Donald Graft's adaptive kernel
5397 deinterling. Work on interlaced parts of a video to produce
5400 The description of the accepted parameters follows.
5404 Set the threshold which affects the filter's tolerance when
5405 determining if a pixel line must be processed. It must be an integer
5406 in the range [0,255] and defaults to 10. A value of 0 will result in
5407 applying the process on every pixels.
5410 Paint pixels exceeding the threshold value to white if set to 1.
5414 Set the fields order. Swap fields if set to 1, leave fields alone if
5418 Enable additional sharpening if set to 1. Default is 0.
5421 Enable twoway sharpening if set to 1. Default is 0.
5424 @subsection Examples
5428 Apply default values:
5430 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5434 Enable additional sharpening:
5440 Paint processed pixels in white:
5449 Apply a 3D LUT to an input video.
5451 The filter accepts the following options:
5455 Set the 3D LUT file name.
5457 Currently supported formats:
5469 Select interpolation mode.
5471 Available values are:
5475 Use values from the nearest defined point.
5477 Interpolate values using the 8 points defining a cube.
5479 Interpolate values using a tetrahedron.
5483 @section lut, lutrgb, lutyuv
5485 Compute a look-up table for binding each pixel component input value
5486 to an output value, and apply it to the input video.
5488 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5489 to an RGB input video.
5491 These filters accept the following parameters:
5494 set first pixel component expression
5496 set second pixel component expression
5498 set third pixel component expression
5500 set fourth pixel component expression, corresponds to the alpha component
5503 set red component expression
5505 set green component expression
5507 set blue component expression
5509 alpha component expression
5512 set Y/luminance component expression
5514 set U/Cb component expression
5516 set V/Cr component expression
5519 Each of them specifies the expression to use for computing the lookup table for
5520 the corresponding pixel component values.
5522 The exact component associated to each of the @var{c*} options depends on the
5525 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5526 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5528 The expressions can contain the following constants and functions:
5533 The input width and height.
5536 The input value for the pixel component.
5539 The input value, clipped to the @var{minval}-@var{maxval} range.
5542 The maximum value for the pixel component.
5545 The minimum value for the pixel component.
5548 The negated value for the pixel component value, clipped to the
5549 @var{minval}-@var{maxval} range; it corresponds to the expression
5550 "maxval-clipval+minval".
5553 The computed value in @var{val}, clipped to the
5554 @var{minval}-@var{maxval} range.
5556 @item gammaval(gamma)
5557 The computed gamma correction value of the pixel component value,
5558 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
5560 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
5564 All expressions default to "val".
5566 @subsection Examples
5572 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
5573 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
5576 The above is the same as:
5578 lutrgb="r=negval:g=negval:b=negval"
5579 lutyuv="y=negval:u=negval:v=negval"
5589 Remove chroma components, turning the video into a graytone image:
5591 lutyuv="u=128:v=128"
5595 Apply a luma burning effect:
5601 Remove green and blue components:
5607 Set a constant alpha channel value on input:
5609 format=rgba,lutrgb=a="maxval-minval/2"
5613 Correct luminance gamma by a factor of 0.5:
5615 lutyuv=y=gammaval(0.5)
5619 Discard least significant bits of luma:
5621 lutyuv=y='bitand(val, 128+64+32)'
5625 @section mergeplanes
5627 Merge color channel components from several video streams.
5629 The filter accepts up to 4 input streams, and merge selected input
5630 planes to the output video.
5632 This filter accepts the following options:
5635 Set input to output plane mapping. Default is @code{0}.
5637 The mappings is specified as a bitmap. It should be specified as a
5638 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
5639 mapping for the first plane of the output stream. 'A' sets the number of
5640 the input stream to use (from 0 to 3), and 'a' the plane number of the
5641 corresponding input to use (from 0 to 3). The rest of the mappings is
5642 similar, 'Bb' describes the mapping for the output stream second
5643 plane, 'Cc' describes the mapping for the output stream third plane and
5644 'Dd' describes the mapping for the output stream fourth plane.
5647 Set output pixel format. Default is @code{yuva444p}.
5650 @subsection Examples
5654 Merge three gray video streams of same width and height into single video stream:
5656 [a0][a1][a2]mergeplanes=0x001020:yuv444p
5660 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
5662 [a0][a1]mergeplanes=0x00010210:yuva444p
5666 Swap Y and A plane in yuva444p stream:
5668 format=yuva444p,mergeplanes=0x03010200:yuva444p
5672 Swap U and V plane in yuv420p stream:
5674 format=yuv420p,mergeplanes=0x000201:yuv420p
5678 Cast a rgb24 clip to yuv444p:
5680 format=rgb24,mergeplanes=0x000102:yuv444p
5686 Apply motion-compensation deinterlacing.
5688 It needs one field per frame as input and must thus be used together
5689 with yadif=1/3 or equivalent.
5691 This filter accepts the following options:
5694 Set the deinterlacing mode.
5696 It accepts one of the following values:
5701 use iterative motion estimation
5703 like @samp{slow}, but use multiple reference frames.
5705 Default value is @samp{fast}.
5708 Set the picture field parity assumed for the input video. It must be
5709 one of the following values:
5713 assume top field first
5715 assume bottom field first
5718 Default value is @samp{bff}.
5721 Set per-block quantization parameter (QP) used by the internal
5724 Higher values should result in a smoother motion vector field but less
5725 optimal individual vectors. Default value is 1.
5730 Apply an MPlayer filter to the input video.
5732 This filter provides a wrapper around some of the filters of
5735 This wrapper is considered experimental. Some of the wrapped filters
5736 may not work properly and we may drop support for them, as they will
5737 be implemented natively into FFmpeg. Thus you should avoid
5738 depending on them when writing portable scripts.
5740 The filter accepts the parameters:
5741 @var{filter_name}[:=]@var{filter_params}
5743 @var{filter_name} is the name of a supported MPlayer filter,
5744 @var{filter_params} is a string containing the parameters accepted by
5747 The list of the currently supported filters follows:
5758 The parameter syntax and behavior for the listed filters are the same
5759 of the corresponding MPlayer filters. For detailed instructions check
5760 the "VIDEO FILTERS" section in the MPlayer manual.
5762 @subsection Examples
5766 Adjust gamma, brightness, contrast:
5772 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
5776 Drop frames that do not differ greatly from the previous frame in
5777 order to reduce frame rate.
5779 The main use of this filter is for very-low-bitrate encoding
5780 (e.g. streaming over dialup modem), but it could in theory be used for
5781 fixing movies that were inverse-telecined incorrectly.
5783 A description of the accepted options follows.
5787 Set the maximum number of consecutive frames which can be dropped (if
5788 positive), or the minimum interval between dropped frames (if
5789 negative). If the value is 0, the frame is dropped unregarding the
5790 number of previous sequentially dropped frames.
5797 Set the dropping threshold values.
5799 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
5800 represent actual pixel value differences, so a threshold of 64
5801 corresponds to 1 unit of difference for each pixel, or the same spread
5802 out differently over the block.
5804 A frame is a candidate for dropping if no 8x8 blocks differ by more
5805 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
5806 meaning the whole image) differ by more than a threshold of @option{lo}.
5808 Default value for @option{hi} is 64*12, default value for @option{lo} is
5809 64*5, and default value for @option{frac} is 0.33.
5817 It accepts an integer in input; if non-zero it negates the
5818 alpha component (if available). The default value in input is 0.
5822 Force libavfilter not to use any of the specified pixel formats for the
5823 input to the next filter.
5825 It accepts the following parameters:
5829 A '|'-separated list of pixel format names, such as
5830 apix_fmts=yuv420p|monow|rgb24".
5834 @subsection Examples
5838 Force libavfilter to use a format different from @var{yuv420p} for the
5839 input to the vflip filter:
5841 noformat=pix_fmts=yuv420p,vflip
5845 Convert the input video to any of the formats not contained in the list:
5847 noformat=yuv420p|yuv444p|yuv410p
5853 Add noise on video input frame.
5855 The filter accepts the following options:
5863 Set noise seed for specific pixel component or all pixel components in case
5864 of @var{all_seed}. Default value is @code{123457}.
5866 @item all_strength, alls
5867 @item c0_strength, c0s
5868 @item c1_strength, c1s
5869 @item c2_strength, c2s
5870 @item c3_strength, c3s
5871 Set noise strength for specific pixel component or all pixel components in case
5872 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
5874 @item all_flags, allf
5879 Set pixel component flags or set flags for all components if @var{all_flags}.
5880 Available values for component flags are:
5883 averaged temporal noise (smoother)
5885 mix random noise with a (semi)regular pattern
5887 temporal noise (noise pattern changes between frames)
5889 uniform noise (gaussian otherwise)
5893 @subsection Examples
5895 Add temporal and uniform noise to input video:
5897 noise=alls=20:allf=t+u
5902 Pass the video source unchanged to the output.
5906 Apply a video transform using libopencv.
5908 To enable this filter, install the libopencv library and headers and
5909 configure FFmpeg with @code{--enable-libopencv}.
5911 It accepts the following parameters:
5916 The name of the libopencv filter to apply.
5919 The parameters to pass to the libopencv filter. If not specified, the default
5924 Refer to the official libopencv documentation for more precise
5926 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
5928 Several libopencv filters are supported; see the following subsections.
5933 Dilate an image by using a specific structuring element.
5934 It corresponds to the libopencv function @code{cvDilate}.
5936 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
5938 @var{struct_el} represents a structuring element, and has the syntax:
5939 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
5941 @var{cols} and @var{rows} represent the number of columns and rows of
5942 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
5943 point, and @var{shape} the shape for the structuring element. @var{shape}
5944 must be "rect", "cross", "ellipse", or "custom".
5946 If the value for @var{shape} is "custom", it must be followed by a
5947 string of the form "=@var{filename}". The file with name
5948 @var{filename} is assumed to represent a binary image, with each
5949 printable character corresponding to a bright pixel. When a custom
5950 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
5951 or columns and rows of the read file are assumed instead.
5953 The default value for @var{struct_el} is "3x3+0x0/rect".
5955 @var{nb_iterations} specifies the number of times the transform is
5956 applied to the image, and defaults to 1.
5960 # Use the default values
5963 # Dilate using a structuring element with a 5x5 cross, iterating two times
5964 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
5966 # Read the shape from the file diamond.shape, iterating two times.
5967 # The file diamond.shape may contain a pattern of characters like this
5973 # The specified columns and rows are ignored
5974 # but the anchor point coordinates are not
5975 ocv=dilate:0x0+2x2/custom=diamond.shape|2
5980 Erode an image by using a specific structuring element.
5981 It corresponds to the libopencv function @code{cvErode}.
5983 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
5984 with the same syntax and semantics as the @ref{dilate} filter.
5988 Smooth the input video.
5990 The filter takes the following parameters:
5991 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
5993 @var{type} is the type of smooth filter to apply, and must be one of
5994 the following values: "blur", "blur_no_scale", "median", "gaussian",
5995 or "bilateral". The default value is "gaussian".
5997 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
5998 depend on the smooth type. @var{param1} and
5999 @var{param2} accept integer positive values or 0. @var{param3} and
6000 @var{param4} accept floating point values.
6002 The default value for @var{param1} is 3. The default value for the
6003 other parameters is 0.
6005 These parameters correspond to the parameters assigned to the
6006 libopencv function @code{cvSmooth}.
6011 Overlay one video on top of another.
6013 It takes two inputs and has one output. The first input is the "main"
6014 video on which the second input is overlayed.
6016 It accepts the following parameters:
6018 A description of the accepted options follows.
6023 Set the expression for the x and y coordinates of the overlayed video
6024 on the main video. Default value is "0" for both expressions. In case
6025 the expression is invalid, it is set to a huge value (meaning that the
6026 overlay will not be displayed within the output visible area).
6029 The action to take when EOF is encountered on the secondary input; it accepts
6030 one of the following values:
6034 Repeat the last frame (the default).
6038 Pass the main input through.
6042 Set when the expressions for @option{x}, and @option{y} are evaluated.
6044 It accepts the following values:
6047 only evaluate expressions once during the filter initialization or
6048 when a command is processed
6051 evaluate expressions for each incoming frame
6054 Default value is @samp{frame}.
6057 If set to 1, force the output to terminate when the shortest input
6058 terminates. Default value is 0.
6061 Set the format for the output video.
6063 It accepts the following values:
6078 Default value is @samp{yuv420}.
6080 @item rgb @emph{(deprecated)}
6081 If set to 1, force the filter to accept inputs in the RGB
6082 color space. Default value is 0. This option is deprecated, use
6083 @option{format} instead.
6086 If set to 1, force the filter to draw the last overlay frame over the
6087 main input until the end of the stream. A value of 0 disables this
6088 behavior. Default value is 1.
6091 The @option{x}, and @option{y} expressions can contain the following
6097 The main input width and height.
6101 The overlay input width and height.
6105 The computed values for @var{x} and @var{y}. They are evaluated for
6110 horizontal and vertical chroma subsample values of the output
6111 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6115 the number of input frame, starting from 0
6118 the position in the file of the input frame, NAN if unknown
6121 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6125 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6126 when evaluation is done @emph{per frame}, and will evaluate to NAN
6127 when @option{eval} is set to @samp{init}.
6129 Be aware that frames are taken from each input video in timestamp
6130 order, hence, if their initial timestamps differ, it is a good idea
6131 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6132 have them begin in the same zero timestamp, as the example for
6133 the @var{movie} filter does.
6135 You can chain together more overlays but you should test the
6136 efficiency of such approach.
6138 @subsection Commands
6140 This filter supports the following commands:
6144 Modify the x and y of the overlay input.
6145 The command accepts the same syntax of the corresponding option.
6147 If the specified expression is not valid, it is kept at its current
6151 @subsection Examples
6155 Draw the overlay at 10 pixels from the bottom right corner of the main
6158 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6161 Using named options the example above becomes:
6163 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6167 Insert a transparent PNG logo in the bottom left corner of the input,
6168 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6170 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6174 Insert 2 different transparent PNG logos (second logo on bottom
6175 right corner) using the @command{ffmpeg} tool:
6177 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
6181 Add a transparent color layer on top of the main video; @code{WxH}
6182 must specify the size of the main input to the overlay filter:
6184 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6188 Play an original video and a filtered version (here with the deshake
6189 filter) side by side using the @command{ffplay} tool:
6191 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6194 The above command is the same as:
6196 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6200 Make a sliding overlay appearing from the left to the right top part of the
6201 screen starting since time 2:
6203 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6207 Compose output by putting two input videos side to side:
6209 ffmpeg -i left.avi -i right.avi -filter_complex "
6210 nullsrc=size=200x100 [background];
6211 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6212 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6213 [background][left] overlay=shortest=1 [background+left];
6214 [background+left][right] overlay=shortest=1:x=100 [left+right]
6219 Mask 10-20 seconds of a video by applying the delogo filter to a section
6221 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6222 -vf '[in]split[split_main][split_delogo];[split_delogo]trim=start=360:end=371,delogo=0:0:640:480[delogoed];[split_main][delogoed]overlay=eof_action=pass[out]'
6227 Chain several overlays in cascade:
6229 nullsrc=s=200x200 [bg];
6230 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6231 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6232 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6233 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6234 [in3] null, [mid2] overlay=100:100 [out0]
6241 Apply Overcomplete Wavelet denoiser.
6243 The filter accepts the following options:
6249 Larger depth values will denoise lower frequency components more, but
6250 slow down filtering.
6252 Must be an int in the range 8-16, default is @code{8}.
6254 @item luma_strength, ls
6257 Must be a double value in the range 0-1000, default is @code{1.0}.
6259 @item chroma_strength, cs
6260 Set chroma strength.
6262 Must be a double value in the range 0-1000, default is @code{1.0}.
6267 Add paddings to the input image, and place the original input at the
6268 provided @var{x}, @var{y} coordinates.
6270 It accepts the following parameters:
6275 Specify an expression for the size of the output image with the
6276 paddings added. If the value for @var{width} or @var{height} is 0, the
6277 corresponding input size is used for the output.
6279 The @var{width} expression can reference the value set by the
6280 @var{height} expression, and vice versa.
6282 The default value of @var{width} and @var{height} is 0.
6286 Specify the offsets to place the input image at within the padded area,
6287 with respect to the top/left border of the output image.
6289 The @var{x} expression can reference the value set by the @var{y}
6290 expression, and vice versa.
6292 The default value of @var{x} and @var{y} is 0.
6295 Specify the color of the padded area. For the syntax of this option,
6296 check the "Color" section in the ffmpeg-utils manual.
6298 The default value of @var{color} is "black".
6301 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6302 options are expressions containing the following constants:
6307 The input video width and height.
6311 These are the same as @var{in_w} and @var{in_h}.
6315 The output width and height (the size of the padded area), as
6316 specified by the @var{width} and @var{height} expressions.
6320 These are the same as @var{out_w} and @var{out_h}.
6324 The x and y offsets as specified by the @var{x} and @var{y}
6325 expressions, or NAN if not yet specified.
6328 same as @var{iw} / @var{ih}
6331 input sample aspect ratio
6334 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6338 The horizontal and vertical chroma subsample values. For example for the
6339 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6342 @subsection Examples
6346 Add paddings with the color "violet" to the input video. The output video
6347 size is 640x480, and the top-left corner of the input video is placed at
6350 pad=640:480:0:40:violet
6353 The example above is equivalent to the following command:
6355 pad=width=640:height=480:x=0:y=40:color=violet
6359 Pad the input to get an output with dimensions increased by 3/2,
6360 and put the input video at the center of the padded area:
6362 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6366 Pad the input to get a squared output with size equal to the maximum
6367 value between the input width and height, and put the input video at
6368 the center of the padded area:
6370 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6374 Pad the input to get a final w/h ratio of 16:9:
6376 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6380 In case of anamorphic video, in order to set the output display aspect
6381 correctly, it is necessary to use @var{sar} in the expression,
6382 according to the relation:
6384 (ih * X / ih) * sar = output_dar
6385 X = output_dar / sar
6388 Thus the previous example needs to be modified to:
6390 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6394 Double the output size and put the input video in the bottom-right
6395 corner of the output padded area:
6397 pad="2*iw:2*ih:ow-iw:oh-ih"
6401 @section perspective
6403 Correct perspective of video not recorded perpendicular to the screen.
6405 A description of the accepted parameters follows.
6416 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6417 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6419 The expressions can use the following variables:
6424 the width and height of video frame.
6428 Set interpolation for perspective correction.
6430 It accepts the following values:
6436 Default value is @samp{linear}.
6441 Delay interlaced video by one field time so that the field order changes.
6443 The intended use is to fix PAL movies that have been captured with the
6444 opposite field order to the film-to-video transfer.
6446 A description of the accepted parameters follows.
6452 It accepts the following values:
6455 Capture field order top-first, transfer bottom-first.
6456 Filter will delay the bottom field.
6459 Capture field order bottom-first, transfer top-first.
6460 Filter will delay the top field.
6463 Capture and transfer with the same field order. This mode only exists
6464 for the documentation of the other options to refer to, but if you
6465 actually select it, the filter will faithfully do nothing.
6468 Capture field order determined automatically by field flags, transfer
6470 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6471 basis using field flags. If no field information is available,
6472 then this works just like @samp{u}.
6475 Capture unknown or varying, transfer opposite.
6476 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6477 analyzing the images and selecting the alternative that produces best
6478 match between the fields.
6481 Capture top-first, transfer unknown or varying.
6482 Filter selects among @samp{t} and @samp{p} using image analysis.
6485 Capture bottom-first, transfer unknown or varying.
6486 Filter selects among @samp{b} and @samp{p} using image analysis.
6489 Capture determined by field flags, transfer unknown or varying.
6490 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6491 image analysis. If no field information is available, then this works just
6492 like @samp{U}. This is the default mode.
6495 Both capture and transfer unknown or varying.
6496 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
6500 @section pixdesctest
6502 Pixel format descriptor test filter, mainly useful for internal
6503 testing. The output video should be equal to the input video.
6507 format=monow, pixdesctest
6510 can be used to test the monowhite pixel format descriptor definition.
6514 Enable the specified chain of postprocessing subfilters using libpostproc. This
6515 library should be automatically selected with a GPL build (@code{--enable-gpl}).
6516 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
6517 Each subfilter and some options have a short and a long name that can be used
6518 interchangeably, i.e. dr/dering are the same.
6520 The filters accept the following options:
6524 Set postprocessing subfilters string.
6527 All subfilters share common options to determine their scope:
6531 Honor the quality commands for this subfilter.
6534 Do chrominance filtering, too (default).
6537 Do luminance filtering only (no chrominance).
6540 Do chrominance filtering only (no luminance).
6543 These options can be appended after the subfilter name, separated by a '|'.
6545 Available subfilters are:
6548 @item hb/hdeblock[|difference[|flatness]]
6549 Horizontal deblocking filter
6552 Difference factor where higher values mean more deblocking (default: @code{32}).
6554 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6557 @item vb/vdeblock[|difference[|flatness]]
6558 Vertical deblocking filter
6561 Difference factor where higher values mean more deblocking (default: @code{32}).
6563 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6566 @item ha/hadeblock[|difference[|flatness]]
6567 Accurate horizontal deblocking filter
6570 Difference factor where higher values mean more deblocking (default: @code{32}).
6572 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6575 @item va/vadeblock[|difference[|flatness]]
6576 Accurate vertical deblocking filter
6579 Difference factor where higher values mean more deblocking (default: @code{32}).
6581 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6585 The horizontal and vertical deblocking filters share the difference and
6586 flatness values so you cannot set different horizontal and vertical
6591 Experimental horizontal deblocking filter
6594 Experimental vertical deblocking filter
6599 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
6602 larger -> stronger filtering
6604 larger -> stronger filtering
6606 larger -> stronger filtering
6609 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
6612 Stretch luminance to @code{0-255}.
6615 @item lb/linblenddeint
6616 Linear blend deinterlacing filter that deinterlaces the given block by
6617 filtering all lines with a @code{(1 2 1)} filter.
6619 @item li/linipoldeint
6620 Linear interpolating deinterlacing filter that deinterlaces the given block by
6621 linearly interpolating every second line.
6623 @item ci/cubicipoldeint
6624 Cubic interpolating deinterlacing filter deinterlaces the given block by
6625 cubically interpolating every second line.
6627 @item md/mediandeint
6628 Median deinterlacing filter that deinterlaces the given block by applying a
6629 median filter to every second line.
6631 @item fd/ffmpegdeint
6632 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
6633 second line with a @code{(-1 4 2 4 -1)} filter.
6636 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
6637 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
6639 @item fq/forceQuant[|quantizer]
6640 Overrides the quantizer table from the input with the constant quantizer you
6648 Default pp filter combination (@code{hb|a,vb|a,dr|a})
6651 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
6654 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
6657 @subsection Examples
6661 Apply horizontal and vertical deblocking, deringing and automatic
6662 brightness/contrast:
6668 Apply default filters without brightness/contrast correction:
6674 Apply default filters and temporal denoiser:
6676 pp=default/tmpnoise|1|2|3
6680 Apply deblocking on luminance only, and switch vertical deblocking on or off
6681 automatically depending on available CPU time:
6689 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
6690 Ratio) between two input videos.
6692 This filter takes in input two input videos, the first input is
6693 considered the "main" source and is passed unchanged to the
6694 output. The second input is used as a "reference" video for computing
6697 Both video inputs must have the same resolution and pixel format for
6698 this filter to work correctly. Also it assumes that both inputs
6699 have the same number of frames, which are compared one by one.
6701 The obtained average PSNR is printed through the logging system.
6703 The filter stores the accumulated MSE (mean squared error) of each
6704 frame, and at the end of the processing it is averaged across all frames
6705 equally, and the following formula is applied to obtain the PSNR:
6708 PSNR = 10*log10(MAX^2/MSE)
6711 Where MAX is the average of the maximum values of each component of the
6714 The description of the accepted parameters follows.
6718 If specified the filter will use the named file to save the PSNR of
6719 each individual frame.
6722 The file printed if @var{stats_file} is selected, contains a sequence of
6723 key/value pairs of the form @var{key}:@var{value} for each compared
6726 A description of each shown parameter follows:
6730 sequential number of the input frame, starting from 1
6733 Mean Square Error pixel-by-pixel average difference of the compared
6734 frames, averaged over all the image components.
6736 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
6737 Mean Square Error pixel-by-pixel average difference of the compared
6738 frames for the component specified by the suffix.
6740 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
6741 Peak Signal to Noise ratio of the compared frames for the component
6742 specified by the suffix.
6747 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
6748 [main][ref] psnr="stats_file=stats.log" [out]
6751 On this example the input file being processed is compared with the
6752 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
6753 is stored in @file{stats.log}.
6758 Pulldown reversal (inverse telecine) filter, capable of handling mixed
6759 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
6762 The pullup filter is designed to take advantage of future context in making
6763 its decisions. This filter is stateless in the sense that it does not lock
6764 onto a pattern to follow, but it instead looks forward to the following
6765 fields in order to identify matches and rebuild progressive frames.
6767 To produce content with an even framerate, insert the fps filter after
6768 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
6769 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
6771 The filter accepts the following options:
6778 These options set the amount of "junk" to ignore at the left, right, top, and
6779 bottom of the image, respectively. Left and right are in units of 8 pixels,
6780 while top and bottom are in units of 2 lines.
6781 The default is 8 pixels on each side.
6784 Set the strict breaks. Setting this option to 1 will reduce the chances of
6785 filter generating an occasional mismatched frame, but it may also cause an
6786 excessive number of frames to be dropped during high motion sequences.
6787 Conversely, setting it to -1 will make filter match fields more easily.
6788 This may help processing of video where there is slight blurring between
6789 the fields, but may also cause there to be interlaced frames in the output.
6790 Default value is @code{0}.
6793 Set the metric plane to use. It accepts the following values:
6799 Use chroma blue plane.
6802 Use chroma red plane.
6805 This option may be set to use chroma plane instead of the default luma plane
6806 for doing filter's computations. This may improve accuracy on very clean
6807 source material, but more likely will decrease accuracy, especially if there
6808 is chroma noise (rainbow effect) or any grayscale video.
6809 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
6810 load and make pullup usable in realtime on slow machines.
6813 For best results (without duplicated frames in the output file) it is
6814 necessary to change the output frame rate. For example, to inverse
6815 telecine NTSC input:
6817 ffmpeg -i input -vf pullup -r 24000/1001 ...
6822 Suppress a TV station logo, using an image file to determine which
6823 pixels comprise the logo. It works by filling in the pixels that
6824 comprise the logo with neighboring pixels.
6826 The filter accepts the following options:
6830 Set the filter bitmap file, which can be any image format supported by
6831 libavformat. The width and height of the image file must match those of the
6832 video stream being processed.
6835 Pixels in the provided bitmap image with a value of zero are not
6836 considered part of the logo, non-zero pixels are considered part of
6837 the logo. If you use white (255) for the logo and black (0) for the
6838 rest, you will be safe. For making the filter bitmap, it is
6839 recommended to take a screen capture of a black frame with the logo
6840 visible, and then using a threshold filter followed by the erode
6841 filter once or twice.
6843 If needed, little splotches can be fixed manually. Remember that if
6844 logo pixels are not covered, the filter quality will be much
6845 reduced. Marking too many pixels as part of the logo does not hurt as
6846 much, but it will increase the amount of blurring needed to cover over
6847 the image and will destroy more information than necessary, and extra
6848 pixels will slow things down on a large logo.
6852 Rotate video by an arbitrary angle expressed in radians.
6854 The filter accepts the following options:
6856 A description of the optional parameters follows.
6859 Set an expression for the angle by which to rotate the input video
6860 clockwise, expressed as a number of radians. A negative value will
6861 result in a counter-clockwise rotation. By default it is set to "0".
6863 This expression is evaluated for each frame.
6866 Set the output width expression, default value is "iw".
6867 This expression is evaluated just once during configuration.
6870 Set the output height expression, default value is "ih".
6871 This expression is evaluated just once during configuration.
6874 Enable bilinear interpolation if set to 1, a value of 0 disables
6875 it. Default value is 1.
6878 Set the color used to fill the output area not covered by the rotated
6879 image. For the generalsyntax of this option, check the "Color" section in the
6880 ffmpeg-utils manual. If the special value "none" is selected then no
6881 background is printed (useful for example if the background is never shown).
6883 Default value is "black".
6886 The expressions for the angle and the output size can contain the
6887 following constants and functions:
6891 sequential number of the input frame, starting from 0. It is always NAN
6892 before the first frame is filtered.
6895 time in seconds of the input frame, it is set to 0 when the filter is
6896 configured. It is always NAN before the first frame is filtered.
6900 horizontal and vertical chroma subsample values. For example for the
6901 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6905 the input video width and height
6909 the output width and height, that is the size of the padded area as
6910 specified by the @var{width} and @var{height} expressions
6914 the minimal width/height required for completely containing the input
6915 video rotated by @var{a} radians.
6917 These are only available when computing the @option{out_w} and
6918 @option{out_h} expressions.
6921 @subsection Examples
6925 Rotate the input by PI/6 radians clockwise:
6931 Rotate the input by PI/6 radians counter-clockwise:
6937 Rotate the input by 45 degrees clockwise:
6943 Apply a constant rotation with period T, starting from an angle of PI/3:
6945 rotate=PI/3+2*PI*t/T
6949 Make the input video rotation oscillating with a period of T
6950 seconds and an amplitude of A radians:
6952 rotate=A*sin(2*PI/T*t)
6956 Rotate the video, output size is chosen so that the whole rotating
6957 input video is always completely contained in the output:
6959 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
6963 Rotate the video, reduce the output size so that no background is ever
6966 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
6970 @subsection Commands
6972 The filter supports the following commands:
6976 Set the angle expression.
6977 The command accepts the same syntax of the corresponding option.
6979 If the specified expression is not valid, it is kept at its current
6985 Apply Shape Adaptive Blur.
6987 The filter accepts the following options:
6990 @item luma_radius, lr
6991 Set luma blur filter strength, must be a value in range 0.1-4.0, default
6992 value is 1.0. A greater value will result in a more blurred image, and
6993 in slower processing.
6995 @item luma_pre_filter_radius, lpfr
6996 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
6999 @item luma_strength, ls
7000 Set luma maximum difference between pixels to still be considered, must
7001 be a value in the 0.1-100.0 range, default value is 1.0.
7003 @item chroma_radius, cr
7004 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
7005 greater value will result in a more blurred image, and in slower
7008 @item chroma_pre_filter_radius, cpfr
7009 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
7011 @item chroma_strength, cs
7012 Set chroma maximum difference between pixels to still be considered,
7013 must be a value in the 0.1-100.0 range.
7016 Each chroma option value, if not explicitly specified, is set to the
7017 corresponding luma option value.
7022 Scale (resize) the input video, using the libswscale library.
7024 The scale filter forces the output display aspect ratio to be the same
7025 of the input, by changing the output sample aspect ratio.
7027 If the input image format is different from the format requested by
7028 the next filter, the scale filter will convert the input to the
7032 The filter accepts the following options, or any of the options
7033 supported by the libswscale scaler.
7035 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
7036 the complete list of scaler options.
7041 Set the output video dimension expression. Default value is the input
7044 If the value is 0, the input width is used for the output.
7046 If one of the values is -1, the scale filter will use a value that
7047 maintains the aspect ratio of the input image, calculated from the
7048 other specified dimension. If both of them are -1, the input size is
7051 If one of the values is -n with n > 1, the scale filter will also use a value
7052 that maintains the aspect ratio of the input image, calculated from the other
7053 specified dimension. After that it will, however, make sure that the calculated
7054 dimension is divisible by n and adjust the value if necessary.
7056 See below for the list of accepted constants for use in the dimension
7060 Set the interlacing mode. It accepts the following values:
7064 Force interlaced aware scaling.
7067 Do not apply interlaced scaling.
7070 Select interlaced aware scaling depending on whether the source frames
7071 are flagged as interlaced or not.
7074 Default value is @samp{0}.
7077 Set libswscale scaling flags. See
7078 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7079 complete list of values. If not explicitly specified the filter applies
7083 Set the video size. For the syntax of this option, check the "Video size"
7084 section in the ffmpeg-utils manual.
7086 @item in_color_matrix
7087 @item out_color_matrix
7088 Set in/output YCbCr color space type.
7090 This allows the autodetected value to be overridden as well as allows forcing
7091 a specific value used for the output and encoder.
7093 If not specified, the color space type depends on the pixel format.
7099 Choose automatically.
7102 Format conforming to International Telecommunication Union (ITU)
7103 Recommendation BT.709.
7106 Set color space conforming to the United States Federal Communications
7107 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7110 Set color space conforming to:
7114 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7117 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7120 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7125 Set color space conforming to SMPTE ST 240:1999.
7130 Set in/output YCbCr sample range.
7132 This allows the autodetected value to be overridden as well as allows forcing
7133 a specific value used for the output and encoder. If not specified, the
7134 range depends on the pixel format. Possible values:
7138 Choose automatically.
7141 Set full range (0-255 in case of 8-bit luma).
7144 Set "MPEG" range (16-235 in case of 8-bit luma).
7147 @item force_original_aspect_ratio
7148 Enable decreasing or increasing output video width or height if necessary to
7149 keep the original aspect ratio. Possible values:
7153 Scale the video as specified and disable this feature.
7156 The output video dimensions will automatically be decreased if needed.
7159 The output video dimensions will automatically be increased if needed.
7163 One useful instance of this option is that when you know a specific device's
7164 maximum allowed resolution, you can use this to limit the output video to
7165 that, while retaining the aspect ratio. For example, device A allows
7166 1280x720 playback, and your video is 1920x800. Using this option (set it to
7167 decrease) and specifying 1280x720 to the command line makes the output
7170 Please note that this is a different thing than specifying -1 for @option{w}
7171 or @option{h}, you still need to specify the output resolution for this option
7176 The values of the @option{w} and @option{h} options are expressions
7177 containing the following constants:
7182 The input width and height
7186 These are the same as @var{in_w} and @var{in_h}.
7190 The output (scaled) width and height
7194 These are the same as @var{out_w} and @var{out_h}
7197 The same as @var{iw} / @var{ih}
7200 input sample aspect ratio
7203 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7207 horizontal and vertical input chroma subsample values. For example for the
7208 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7212 horizontal and vertical output chroma subsample values. For example for the
7213 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7216 @subsection Examples
7220 Scale the input video to a size of 200x100
7225 This is equivalent to:
7236 Specify a size abbreviation for the output size:
7241 which can also be written as:
7247 Scale the input to 2x:
7253 The above is the same as:
7259 Scale the input to 2x with forced interlaced scaling:
7261 scale=2*iw:2*ih:interl=1
7265 Scale the input to half size:
7271 Increase the width, and set the height to the same size:
7284 Increase the height, and set the width to 3/2 of the height:
7286 scale=w=3/2*oh:h=3/5*ih
7290 Increase the size, making the size a multiple of the chroma
7293 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7297 Increase the width to a maximum of 500 pixels,
7298 keeping the same aspect ratio as the input:
7300 scale=w='min(500\, iw*3/2):h=-1'
7304 @section separatefields
7306 The @code{separatefields} takes a frame-based video input and splits
7307 each frame into its components fields, producing a new half height clip
7308 with twice the frame rate and twice the frame count.
7310 This filter use field-dominance information in frame to decide which
7311 of each pair of fields to place first in the output.
7312 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7314 @section setdar, setsar
7316 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7319 This is done by changing the specified Sample (aka Pixel) Aspect
7320 Ratio, according to the following equation:
7322 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7325 Keep in mind that the @code{setdar} filter does not modify the pixel
7326 dimensions of the video frame. Also, the display aspect ratio set by
7327 this filter may be changed by later filters in the filterchain,
7328 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7331 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7332 the filter output video.
7334 Note that as a consequence of the application of this filter, the
7335 output display aspect ratio will change according to the equation
7338 Keep in mind that the sample aspect ratio set by the @code{setsar}
7339 filter may be changed by later filters in the filterchain, e.g. if
7340 another "setsar" or a "setdar" filter is applied.
7342 It accepts the following parameters:
7345 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7346 Set the aspect ratio used by the filter.
7348 The parameter can be a floating point number string, an expression, or
7349 a string of the form @var{num}:@var{den}, where @var{num} and
7350 @var{den} are the numerator and denominator of the aspect ratio. If
7351 the parameter is not specified, it is assumed the value "0".
7352 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7356 Set the maximum integer value to use for expressing numerator and
7357 denominator when reducing the expressed aspect ratio to a rational.
7358 Default value is @code{100}.
7362 The parameter @var{sar} is an expression containing
7363 the following constants:
7367 These are approximated values for the mathematical constants e
7368 (Euler's number), pi (Greek pi), and phi (the golden ratio).
7371 The input width and height.
7374 These are the same as @var{w} / @var{h}.
7377 The input sample aspect ratio.
7380 The input display aspect ratio. It is the same as
7381 (@var{w} / @var{h}) * @var{sar}.
7384 Horizontal and vertical chroma subsample values. For example, for the
7385 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7388 @subsection Examples
7393 To change the display aspect ratio to 16:9, specify one of the following:
7401 To change the sample aspect ratio to 10:11, specify:
7407 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7408 1000 in the aspect ratio reduction, use the command:
7410 setdar=ratio=16/9:max=1000
7418 Force field for the output video frame.
7420 The @code{setfield} filter marks the interlace type field for the
7421 output frames. It does not change the input frame, but only sets the
7422 corresponding property, which affects how the frame is treated by
7423 following filters (e.g. @code{fieldorder} or @code{yadif}).
7425 The filter accepts the following options:
7430 Available values are:
7434 Keep the same field property.
7437 Mark the frame as bottom-field-first.
7440 Mark the frame as top-field-first.
7443 Mark the frame as progressive.
7449 Show a line containing various information for each input video frame.
7450 The input video is not modified.
7452 The shown line contains a sequence of key/value pairs of the form
7453 @var{key}:@var{value}.
7455 It accepts the following parameters:
7459 The (sequential) number of the input frame, starting from 0.
7462 The Presentation TimeStamp of the input frame, expressed as a number of
7463 time base units. The time base unit depends on the filter input pad.
7466 The Presentation TimeStamp of the input frame, expressed as a number of
7470 The position of the frame in the input stream, or -1 if this information is
7471 unavailable and/or meaningless (for example in case of synthetic video).
7474 The pixel format name.
7477 The sample aspect ratio of the input frame, expressed in the form
7478 @var{num}/@var{den}.
7481 The size of the input frame. For the syntax of this option, check the "Video size"
7482 section in the ffmpeg-utils manual.
7485 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
7486 for bottom field first).
7489 This is 1 if the frame is a key frame, 0 otherwise.
7492 The picture type of the input frame ("I" for an I-frame, "P" for a
7493 P-frame, "B" for a B-frame, or "?" for an unknown type).
7494 Also refer to the documentation of the @code{AVPictureType} enum and of
7495 the @code{av_get_picture_type_char} function defined in
7496 @file{libavutil/avutil.h}.
7499 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
7501 @item plane_checksum
7502 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
7503 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
7506 @section shuffleplanes
7508 Reorder and/or duplicate video planes.
7510 It accepts the following parameters:
7515 The index of the input plane to be used as the first output plane.
7518 The index of the input plane to be used as the second output plane.
7521 The index of the input plane to be used as the third output plane.
7524 The index of the input plane to be used as the fourth output plane.
7528 The first plane has the index 0. The default is to keep the input unchanged.
7530 Swap the second and third planes of the input:
7532 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
7535 @section signalstats
7536 Evaluate various visual metrics that assist in determining issues associated
7537 with the digitization of analog video media.
7539 By default the filter will log these metadata values:
7543 Display the minimal Y value contained within the input frame. Expressed in
7547 Display the Y value at the 10% percentile within the input frame. Expressed in
7551 Display the average Y value within the input frame. Expressed in range of
7555 Display the Y value at the 90% percentile within the input frame. Expressed in
7559 Display the maximum Y value contained within the input frame. Expressed in
7563 Display the minimal U value contained within the input frame. Expressed in
7567 Display the U value at the 10% percentile within the input frame. Expressed in
7571 Display the average U value within the input frame. Expressed in range of
7575 Display the U value at the 90% percentile within the input frame. Expressed in
7579 Display the maximum U value contained within the input frame. Expressed in
7583 Display the minimal V value contained within the input frame. Expressed in
7587 Display the V value at the 10% percentile within the input frame. Expressed in
7591 Display the average V value within the input frame. Expressed in range of
7595 Display the V value at the 90% percentile within the input frame. Expressed in
7599 Display the maximum V value contained within the input frame. Expressed in
7603 Display the minimal saturation value contained within the input frame.
7604 Expressed in range of [0-~181.02].
7607 Display the saturation value at the 10% percentile within the input frame.
7608 Expressed in range of [0-~181.02].
7611 Display the average saturation value within the input frame. Expressed in range
7615 Display the saturation value at the 90% percentile within the input frame.
7616 Expressed in range of [0-~181.02].
7619 Display the maximum saturation value contained within the input frame.
7620 Expressed in range of [0-~181.02].
7623 Display the median value for hue within the input frame. Expressed in range of
7627 Display the average value for hue within the input frame. Expressed in range of
7631 Display the average of sample value difference between all values of the Y
7632 plane in the current frame and corresponding values of the previous input frame.
7633 Expressed in range of [0-255].
7636 Display the average of sample value difference between all values of the U
7637 plane in the current frame and corresponding values of the previous input frame.
7638 Expressed in range of [0-255].
7641 Display the average of sample value difference between all values of the V
7642 plane in the current frame and corresponding values of the previous input frame.
7643 Expressed in range of [0-255].
7646 The filter accepts the following options:
7652 @option{stat} specify an additional form of image analysis.
7653 @option{out} output video with the specified type of pixel highlighted.
7655 Both options accept the following values:
7659 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
7660 unlike the neighboring pixels of the same field. Examples of temporal outliers
7661 include the results of video dropouts, head clogs, or tape tracking issues.
7664 Identify @var{vertical line repetition}. Vertical line repetition includes
7665 similar rows of pixels within a frame. In born-digital video vertical line
7666 repetition is common, but this pattern is uncommon in video digitized from an
7667 analog source. When it occurs in video that results from the digitization of an
7668 analog source it can indicate concealment from a dropout compensator.
7671 Identify pixels that fall outside of legal broadcast range.
7675 Set the highlight color for the @option{out} option. The default color is
7679 @subsection Examples
7683 Output data of various video metrics:
7685 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
7689 Output specific data about the minimum and maximum values of the Y plane per frame:
7691 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
7695 Playback video while highlighting pixels that are outside of broadcast range in red.
7697 ffplay example.mov -vf values="out=brng:color=red"
7704 Blur the input video without impacting the outlines.
7706 It accepts the following options:
7709 @item luma_radius, lr
7710 Set the luma radius. The option value must be a float number in
7711 the range [0.1,5.0] that specifies the variance of the gaussian filter
7712 used to blur the image (slower if larger). Default value is 1.0.
7714 @item luma_strength, ls
7715 Set the luma strength. The option value must be a float number
7716 in the range [-1.0,1.0] that configures the blurring. A value included
7717 in [0.0,1.0] will blur the image whereas a value included in
7718 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7720 @item luma_threshold, lt
7721 Set the luma threshold used as a coefficient to determine
7722 whether a pixel should be blurred or not. The option value must be an
7723 integer in the range [-30,30]. A value of 0 will filter all the image,
7724 a value included in [0,30] will filter flat areas and a value included
7725 in [-30,0] will filter edges. Default value is 0.
7727 @item chroma_radius, cr
7728 Set the chroma radius. The option value must be a float number in
7729 the range [0.1,5.0] that specifies the variance of the gaussian filter
7730 used to blur the image (slower if larger). Default value is 1.0.
7732 @item chroma_strength, cs
7733 Set the chroma strength. The option value must be a float number
7734 in the range [-1.0,1.0] that configures the blurring. A value included
7735 in [0.0,1.0] will blur the image whereas a value included in
7736 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7738 @item chroma_threshold, ct
7739 Set the chroma threshold used as a coefficient to determine
7740 whether a pixel should be blurred or not. The option value must be an
7741 integer in the range [-30,30]. A value of 0 will filter all the image,
7742 a value included in [0,30] will filter flat areas and a value included
7743 in [-30,0] will filter edges. Default value is 0.
7746 If a chroma option is not explicitly set, the corresponding luma value
7751 Convert between different stereoscopic image formats.
7753 The filters accept the following options:
7757 Set stereoscopic image format of input.
7759 Available values for input image formats are:
7762 side by side parallel (left eye left, right eye right)
7765 side by side crosseye (right eye left, left eye right)
7768 side by side parallel with half width resolution
7769 (left eye left, right eye right)
7772 side by side crosseye with half width resolution
7773 (right eye left, left eye right)
7776 above-below (left eye above, right eye below)
7779 above-below (right eye above, left eye below)
7782 above-below with half height resolution
7783 (left eye above, right eye below)
7786 above-below with half height resolution
7787 (right eye above, left eye below)
7790 alternating frames (left eye first, right eye second)
7793 alternating frames (right eye first, left eye second)
7795 Default value is @samp{sbsl}.
7799 Set stereoscopic image format of output.
7801 Available values for output image formats are all the input formats as well as:
7804 anaglyph red/blue gray
7805 (red filter on left eye, blue filter on right eye)
7808 anaglyph red/green gray
7809 (red filter on left eye, green filter on right eye)
7812 anaglyph red/cyan gray
7813 (red filter on left eye, cyan filter on right eye)
7816 anaglyph red/cyan half colored
7817 (red filter on left eye, cyan filter on right eye)
7820 anaglyph red/cyan color
7821 (red filter on left eye, cyan filter on right eye)
7824 anaglyph red/cyan color optimized with the least squares projection of dubois
7825 (red filter on left eye, cyan filter on right eye)
7828 anaglyph green/magenta gray
7829 (green filter on left eye, magenta filter on right eye)
7832 anaglyph green/magenta half colored
7833 (green filter on left eye, magenta filter on right eye)
7836 anaglyph green/magenta colored
7837 (green filter on left eye, magenta filter on right eye)
7840 anaglyph green/magenta color optimized with the least squares projection of dubois
7841 (green filter on left eye, magenta filter on right eye)
7844 anaglyph yellow/blue gray
7845 (yellow filter on left eye, blue filter on right eye)
7848 anaglyph yellow/blue half colored
7849 (yellow filter on left eye, blue filter on right eye)
7852 anaglyph yellow/blue colored
7853 (yellow filter on left eye, blue filter on right eye)
7856 anaglyph yellow/blue color optimized with the least squares projection of dubois
7857 (yellow filter on left eye, blue filter on right eye)
7860 interleaved rows (left eye has top row, right eye starts on next row)
7863 interleaved rows (right eye has top row, left eye starts on next row)
7866 mono output (left eye only)
7869 mono output (right eye only)
7872 Default value is @samp{arcd}.
7875 @subsection Examples
7879 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
7885 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
7893 Apply a simple postprocessing filter that compresses and decompresses the image
7894 at several (or - in the case of @option{quality} level @code{6} - all) shifts
7895 and average the results.
7897 The filter accepts the following options:
7901 Set quality. This option defines the number of levels for averaging. It accepts
7902 an integer in the range 0-6. If set to @code{0}, the filter will have no
7903 effect. A value of @code{6} means the higher quality. For each increment of
7904 that value the speed drops by a factor of approximately 2. Default value is
7908 Force a constant quantization parameter. If not set, the filter will use the QP
7909 from the video stream (if available).
7912 Set thresholding mode. Available modes are:
7916 Set hard thresholding (default).
7918 Set soft thresholding (better de-ringing effect, but likely blurrier).
7922 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
7923 option may cause flicker since the B-Frames have often larger QP. Default is
7924 @code{0} (not enabled).
7930 Draw subtitles on top of input video using the libass library.
7932 To enable compilation of this filter you need to configure FFmpeg with
7933 @code{--enable-libass}. This filter also requires a build with libavcodec and
7934 libavformat to convert the passed subtitles file to ASS (Advanced Substation
7935 Alpha) subtitles format.
7937 The filter accepts the following options:
7941 Set the filename of the subtitle file to read. It must be specified.
7944 Specify the size of the original video, the video for which the ASS file
7945 was composed. For the syntax of this option, check the "Video size" section in
7946 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
7947 this is necessary to correctly scale the fonts if the aspect ratio has been
7951 Set subtitles input character encoding. @code{subtitles} filter only. Only
7952 useful if not UTF-8.
7954 @item stream_index, si
7955 Set subtitles stream index. @code{subtitles} filter only.
7958 If the first key is not specified, it is assumed that the first value
7959 specifies the @option{filename}.
7961 For example, to render the file @file{sub.srt} on top of the input
7962 video, use the command:
7967 which is equivalent to:
7969 subtitles=filename=sub.srt
7972 To render the default subtitles stream from file @file{video.mkv}, use:
7977 To render the second subtitles stream from that file, use:
7979 subtitles=video.mkv:si=1
7984 Scale the input by 2x and smooth using the Super2xSaI (Scale and
7985 Interpolate) pixel art scaling algorithm.
7987 Useful for enlarging pixel art images without reducing sharpness.
7994 Apply telecine process to the video.
7996 This filter accepts the following options:
8005 The default value is @code{top}.
8009 A string of numbers representing the pulldown pattern you wish to apply.
8010 The default value is @code{23}.
8014 Some typical patterns:
8019 24p: 2332 (preferred)
8026 24p: 222222222223 ("Euro pulldown")
8032 Select the most representative frame in a given sequence of consecutive frames.
8034 The filter accepts the following options:
8038 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
8039 will pick one of them, and then handle the next batch of @var{n} frames until
8040 the end. Default is @code{100}.
8043 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
8044 value will result in a higher memory usage, so a high value is not recommended.
8046 @subsection Examples
8050 Extract one picture each 50 frames:
8056 Complete example of a thumbnail creation with @command{ffmpeg}:
8058 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
8064 Tile several successive frames together.
8066 The filter accepts the following options:
8071 Set the grid size (i.e. the number of lines and columns). For the syntax of
8072 this option, check the "Video size" section in the ffmpeg-utils manual.
8075 Set the maximum number of frames to render in the given area. It must be less
8076 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
8077 the area will be used.
8080 Set the outer border margin in pixels.
8083 Set the inner border thickness (i.e. the number of pixels between frames). For
8084 more advanced padding options (such as having different values for the edges),
8085 refer to the pad video filter.
8088 Specify the color of the unused areaFor the syntax of this option, check the
8089 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
8093 @subsection Examples
8097 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
8099 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
8101 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
8102 duplicating each output frame to accommodate the originally detected frame
8106 Display @code{5} pictures in an area of @code{3x2} frames,
8107 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
8108 mixed flat and named options:
8110 tile=3x2:nb_frames=5:padding=7:margin=2
8116 Perform various types of temporal field interlacing.
8118 Frames are counted starting from 1, so the first input frame is
8121 The filter accepts the following options:
8126 Specify the mode of the interlacing. This option can also be specified
8127 as a value alone. See below for a list of values for this option.
8129 Available values are:
8133 Move odd frames into the upper field, even into the lower field,
8134 generating a double height frame at half frame rate.
8137 Only output even frames, odd frames are dropped, generating a frame with
8138 unchanged height at half frame rate.
8141 Only output odd frames, even frames are dropped, generating a frame with
8142 unchanged height at half frame rate.
8145 Expand each frame to full height, but pad alternate lines with black,
8146 generating a frame with double height at the same input frame rate.
8148 @item interleave_top, 4
8149 Interleave the upper field from odd frames with the lower field from
8150 even frames, generating a frame with unchanged height at half frame rate.
8152 @item interleave_bottom, 5
8153 Interleave the lower field from odd frames with the upper field from
8154 even frames, generating a frame with unchanged height at half frame rate.
8156 @item interlacex2, 6
8157 Double frame rate with unchanged height. Frames are inserted each
8158 containing the second temporal field from the previous input frame and
8159 the first temporal field from the next input frame. This mode relies on
8160 the top_field_first flag. Useful for interlaced video displays with no
8161 field synchronisation.
8164 Numeric values are deprecated but are accepted for backward
8165 compatibility reasons.
8167 Default mode is @code{merge}.
8170 Specify flags influencing the filter process.
8172 Available value for @var{flags} is:
8175 @item low_pass_filter, vlfp
8176 Enable vertical low-pass filtering in the filter.
8177 Vertical low-pass filtering is required when creating an interlaced
8178 destination from a progressive source which contains high-frequency
8179 vertical detail. Filtering will reduce interlace 'twitter' and Moire
8182 Vertical low-pass filtering can only be enabled for @option{mode}
8183 @var{interleave_top} and @var{interleave_bottom}.
8190 Transpose rows with columns in the input video and optionally flip it.
8192 It accepts the following parameters:
8197 Specify the transposition direction.
8199 Can assume the following values:
8201 @item 0, 4, cclock_flip
8202 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
8210 Rotate by 90 degrees clockwise, that is:
8218 Rotate by 90 degrees counterclockwise, that is:
8225 @item 3, 7, clock_flip
8226 Rotate by 90 degrees clockwise and vertically flip, that is:
8234 For values between 4-7, the transposition is only done if the input
8235 video geometry is portrait and not landscape. These values are
8236 deprecated, the @code{passthrough} option should be used instead.
8238 Numerical values are deprecated, and should be dropped in favor of
8242 Do not apply the transposition if the input geometry matches the one
8243 specified by the specified value. It accepts the following values:
8246 Always apply transposition.
8248 Preserve portrait geometry (when @var{height} >= @var{width}).
8250 Preserve landscape geometry (when @var{width} >= @var{height}).
8253 Default value is @code{none}.
8256 For example to rotate by 90 degrees clockwise and preserve portrait
8259 transpose=dir=1:passthrough=portrait
8262 The command above can also be specified as:
8264 transpose=1:portrait
8268 Trim the input so that the output contains one continuous subpart of the input.
8270 It accepts the following parameters:
8273 Specify the time of the start of the kept section, i.e. the frame with the
8274 timestamp @var{start} will be the first frame in the output.
8277 Specify the time of the first frame that will be dropped, i.e. the frame
8278 immediately preceding the one with the timestamp @var{end} will be the last
8279 frame in the output.
8282 This is the same as @var{start}, except this option sets the start timestamp
8283 in timebase units instead of seconds.
8286 This is the same as @var{end}, except this option sets the end timestamp
8287 in timebase units instead of seconds.
8290 The maximum duration of the output in seconds.
8293 The number of the first frame that should be passed to the output.
8296 The number of the first frame that should be dropped.
8299 @option{start}, @option{end}, @option{duration} are expressed as time
8300 duration specifications, check the "Time duration" section in the
8301 ffmpeg-utils manual.
8303 Note that the first two sets of the start/end options and the @option{duration}
8304 option look at the frame timestamp, while the _frame variants simply count the
8305 frames that pass through the filter. Also note that this filter does not modify
8306 the timestamps. If you wish for the output timestamps to start at zero, insert a
8307 setpts filter after the trim filter.
8309 If multiple start or end options are set, this filter tries to be greedy and
8310 keep all the frames that match at least one of the specified constraints. To keep
8311 only the part that matches all the constraints at once, chain multiple trim
8314 The defaults are such that all the input is kept. So it is possible to set e.g.
8315 just the end values to keep everything before the specified time.
8320 Drop everything except the second minute of input:
8322 ffmpeg -i INPUT -vf trim=60:120
8326 Keep only the first second:
8328 ffmpeg -i INPUT -vf trim=duration=1
8336 Sharpen or blur the input video.
8338 It accepts the following parameters:
8341 @item luma_msize_x, lx
8342 Set the luma matrix horizontal size. It must be an odd integer between
8343 3 and 63. The default value is 5.
8345 @item luma_msize_y, ly
8346 Set the luma matrix vertical size. It must be an odd integer between 3
8347 and 63. The default value is 5.
8349 @item luma_amount, la
8350 Set the luma effect strength. It must be a floating point number, reasonable
8351 values lay between -1.5 and 1.5.
8353 Negative values will blur the input video, while positive values will
8354 sharpen it, a value of zero will disable the effect.
8356 Default value is 1.0.
8358 @item chroma_msize_x, cx
8359 Set the chroma matrix horizontal size. It must be an odd integer
8360 between 3 and 63. The default value is 5.
8362 @item chroma_msize_y, cy
8363 Set the chroma matrix vertical size. It must be an odd integer
8364 between 3 and 63. The default value is 5.
8366 @item chroma_amount, ca
8367 Set the chroma effect strength. It must be a floating point number, reasonable
8368 values lay between -1.5 and 1.5.
8370 Negative values will blur the input video, while positive values will
8371 sharpen it, a value of zero will disable the effect.
8373 Default value is 0.0.
8376 If set to 1, specify using OpenCL capabilities, only available if
8377 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
8381 All parameters are optional and default to the equivalent of the
8382 string '5:5:1.0:5:5:0.0'.
8384 @subsection Examples
8388 Apply strong luma sharpen effect:
8390 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
8394 Apply a strong blur of both luma and chroma parameters:
8396 unsharp=7:7:-2:7:7:-2
8400 @anchor{vidstabdetect}
8401 @section vidstabdetect
8403 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
8404 @ref{vidstabtransform} for pass 2.
8406 This filter generates a file with relative translation and rotation
8407 transform information about subsequent frames, which is then used by
8408 the @ref{vidstabtransform} filter.
8410 To enable compilation of this filter you need to configure FFmpeg with
8411 @code{--enable-libvidstab}.
8413 This filter accepts the following options:
8417 Set the path to the file used to write the transforms information.
8418 Default value is @file{transforms.trf}.
8421 Set how shaky the video is and how quick the camera is. It accepts an
8422 integer in the range 1-10, a value of 1 means little shakiness, a
8423 value of 10 means strong shakiness. Default value is 5.
8426 Set the accuracy of the detection process. It must be a value in the
8427 range 1-15. A value of 1 means low accuracy, a value of 15 means high
8428 accuracy. Default value is 15.
8431 Set stepsize of the search process. The region around minimum is
8432 scanned with 1 pixel resolution. Default value is 6.
8435 Set minimum contrast. Below this value a local measurement field is
8436 discarded. Must be a floating point value in the range 0-1. Default
8440 Set reference frame number for tripod mode.
8442 If enabled, the motion of the frames is compared to a reference frame
8443 in the filtered stream, identified by the specified number. The idea
8444 is to compensate all movements in a more-or-less static scene and keep
8445 the camera view absolutely still.
8447 If set to 0, it is disabled. The frames are counted starting from 1.
8450 Show fields and transforms in the resulting frames. It accepts an
8451 integer in the range 0-2. Default value is 0, which disables any
8455 @subsection Examples
8465 Analyze strongly shaky movie and put the results in file
8466 @file{mytransforms.trf}:
8468 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
8472 Visualize the result of internal transformations in the resulting
8475 vidstabdetect=show=1
8479 Analyze a video with medium shakiness using @command{ffmpeg}:
8481 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
8485 @anchor{vidstabtransform}
8486 @section vidstabtransform
8488 Video stabilization/deshaking: pass 2 of 2,
8489 see @ref{vidstabdetect} for pass 1.
8491 Read a file with transform information for each frame and
8492 apply/compensate them. Together with the @ref{vidstabdetect}
8493 filter this can be used to deshake videos. See also
8494 @url{http://public.hronopik.de/vid.stab}. It is important to also use
8495 the unsharp filter, see below.
8497 To enable compilation of this filter you need to configure FFmpeg with
8498 @code{--enable-libvidstab}.
8504 Set path to the file used to read the transforms. Default value is
8505 @file{transforms.trf}).
8508 Set the number of frames (value*2 + 1) used for lowpass filtering the
8509 camera movements. Default value is 10.
8511 For example a number of 10 means that 21 frames are used (10 in the
8512 past and 10 in the future) to smoothen the motion in the video. A
8513 larger values leads to a smoother video, but limits the acceleration
8514 of the camera (pan/tilt movements). 0 is a special case where a
8515 static camera is simulated.
8518 Set the camera path optimization algorithm.
8520 Accepted values are:
8523 gaussian kernel low-pass filter on camera motion (default)
8525 averaging on transformations
8529 Set maximal number of pixels to translate frames. Default value is -1,
8533 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
8534 value is -1, meaning no limit.
8537 Specify how to deal with borders that may be visible due to movement
8540 Available values are:
8543 keep image information from previous frame (default)
8545 fill the border black
8549 Invert transforms if set to 1. Default value is 0.
8552 Consider transforms as relative to previsou frame if set to 1,
8553 absolute if set to 0. Default value is 0.
8556 Set percentage to zoom. A positive value will result in a zoom-in
8557 effect, a negative value in a zoom-out effect. Default value is 0 (no
8561 Set optimal zooming to avoid borders.
8563 Accepted values are:
8568 optimal static zoom value is determined (only very strong movements
8569 will lead to visible borders) (default)
8571 optimal adaptive zoom value is determined (no borders will be
8572 visible), see @option{zoomspeed}
8575 Note that the value given at zoom is added to the one calculated here.
8578 Set percent to zoom maximally each frame (enabled when
8579 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
8583 Specify type of interpolation.
8585 Available values are:
8590 linear only horizontal
8592 linear in both directions (default)
8594 cubic in both directions (slow)
8598 Enable virtual tripod mode if set to 1, which is equivalent to
8599 @code{relative=0:smoothing=0}. Default value is 0.
8601 Use also @code{tripod} option of @ref{vidstabdetect}.
8604 Increase log verbosity if set to 1. Also the detected global motions
8605 are written to the temporary file @file{global_motions.trf}. Default
8609 @subsection Examples
8613 Use @command{ffmpeg} for a typical stabilization with default values:
8615 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
8618 Note the use of the unsharp filter which is always recommended.
8621 Zoom in a bit more and load transform data from a given file:
8623 vidstabtransform=zoom=5:input="mytransforms.trf"
8627 Smoothen the video even more:
8629 vidstabtransform=smoothing=30
8635 Flip the input video vertically.
8637 For example, to vertically flip a video with @command{ffmpeg}:
8639 ffmpeg -i in.avi -vf "vflip" out.avi
8644 Make or reverse a natural vignetting effect.
8646 The filter accepts the following options:
8650 Set lens angle expression as a number of radians.
8652 The value is clipped in the @code{[0,PI/2]} range.
8654 Default value: @code{"PI/5"}
8658 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
8662 Set forward/backward mode.
8664 Available modes are:
8667 The larger the distance from the central point, the darker the image becomes.
8670 The larger the distance from the central point, the brighter the image becomes.
8671 This can be used to reverse a vignette effect, though there is no automatic
8672 detection to extract the lens @option{angle} and other settings (yet). It can
8673 also be used to create a burning effect.
8676 Default value is @samp{forward}.
8679 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
8681 It accepts the following values:
8684 Evaluate expressions only once during the filter initialization.
8687 Evaluate expressions for each incoming frame. This is way slower than the
8688 @samp{init} mode since it requires all the scalers to be re-computed, but it
8689 allows advanced dynamic expressions.
8692 Default value is @samp{init}.
8695 Set dithering to reduce the circular banding effects. Default is @code{1}
8699 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
8700 Setting this value to the SAR of the input will make a rectangular vignetting
8701 following the dimensions of the video.
8703 Default is @code{1/1}.
8706 @subsection Expressions
8708 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
8709 following parameters.
8714 input width and height
8717 the number of input frame, starting from 0
8720 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
8721 @var{TB} units, NAN if undefined
8724 frame rate of the input video, NAN if the input frame rate is unknown
8727 the PTS (Presentation TimeStamp) of the filtered video frame,
8728 expressed in seconds, NAN if undefined
8731 time base of the input video
8735 @subsection Examples
8739 Apply simple strong vignetting effect:
8745 Make a flickering vignetting:
8747 vignette='PI/4+random(1)*PI/50':eval=frame
8754 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
8755 Deinterlacing Filter").
8757 Based on the process described by Martin Weston for BBC R&D, and
8758 implemented based on the de-interlace algorithm written by Jim
8759 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
8760 uses filter coefficients calculated by BBC R&D.
8762 There are two sets of filter coefficients, so called "simple":
8763 and "complex". Which set of filter coefficients is used can
8764 be set by passing an optional parameter:
8768 Set the interlacing filter coefficients. Accepts one of the following values:
8772 Simple filter coefficient set.
8774 More-complex filter coefficient set.
8776 Default value is @samp{complex}.
8779 Specify which frames to deinterlace. Accept one of the following values:
8783 Deinterlace all frames,
8785 Only deinterlace frames marked as interlaced.
8788 Default value is @samp{all}.
8794 Deinterlace the input video ("yadif" means "yet another deinterlacing
8797 It accepts the following parameters:
8803 The interlacing mode to adopt. It accepts one of the following values:
8807 Output one frame for each frame.
8809 Output one frame for each field.
8810 @item 2, send_frame_nospatial
8811 Like @code{send_frame}, but it skips the spatial interlacing check.
8812 @item 3, send_field_nospatial
8813 Like @code{send_field}, but it skips the spatial interlacing check.
8816 The default value is @code{send_frame}.
8819 The picture field parity assumed for the input interlaced video. It accepts one
8820 of the following values:
8824 Assume the top field is first.
8826 Assume the bottom field is first.
8828 Enable automatic detection of field parity.
8831 The default value is @code{auto}.
8832 If the interlacing is unknown or the decoder does not export this information,
8833 top field first will be assumed.
8836 Specify which frames to deinterlace. Accept one of the following
8841 Deinterlace all frames.
8843 Only deinterlace frames marked as interlaced.
8846 The default value is @code{all}.
8851 Apply Zoom & Pan effect.
8853 This filter accepts the following options:
8857 Set the zoom expression. Default is 1.
8861 Set the x and y expression. Default is 0.
8864 Set the duration expression in number of frames.
8865 This sets for how many number of frames effect will last for
8869 Set the output image size, default is 'hd720'.
8872 Each expression can contain the following constants:
8895 Last calculated 'x' and 'y' position from 'x' and 'y' expression
8896 for current input frame.
8900 'x' and 'y' of last output frame of previous input frame or 0 when there was
8901 not yet such frame (first input frame).
8904 Last calculated zoom from 'z' expression for current input frame.
8907 Last calculated zoom of last output frame of previous input frame.
8910 Number of output frames for current input frame. Calculated from 'd' expression
8911 for each input frame.
8914 number of output frames created for previous input frame
8917 Rational number: input width / input height
8923 display aspect ratio
8927 @subsection Examples
8931 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
8933 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='if(gte(zoom,1.5),x,x+1/a)':y='if(gte(zoom,1.5),y,y+1)':s=640x360
8937 @c man end VIDEO FILTERS
8939 @chapter Video Sources
8940 @c man begin VIDEO SOURCES
8942 Below is a description of the currently available video sources.
8946 Buffer video frames, and make them available to the filter chain.
8948 This source is mainly intended for a programmatic use, in particular
8949 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
8951 It accepts the following parameters:
8956 Specify the size (width and height) of the buffered video frames. For the
8957 syntax of this option, check the "Video size" section in the ffmpeg-utils
8961 The input video width.
8964 The input video height.
8967 A string representing the pixel format of the buffered video frames.
8968 It may be a number corresponding to a pixel format, or a pixel format
8972 Specify the timebase assumed by the timestamps of the buffered frames.
8975 Specify the frame rate expected for the video stream.
8977 @item pixel_aspect, sar
8978 The sample (pixel) aspect ratio of the input video.
8981 Specify the optional parameters to be used for the scale filter which
8982 is automatically inserted when an input change is detected in the
8983 input size or format.
8988 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
8991 will instruct the source to accept video frames with size 320x240 and
8992 with format "yuv410p", assuming 1/24 as the timestamps timebase and
8993 square pixels (1:1 sample aspect ratio).
8994 Since the pixel format with name "yuv410p" corresponds to the number 6
8995 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
8996 this example corresponds to:
8998 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
9001 Alternatively, the options can be specified as a flat string, but this
9002 syntax is deprecated:
9004 @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}]
9008 Create a pattern generated by an elementary cellular automaton.
9010 The initial state of the cellular automaton can be defined through the
9011 @option{filename}, and @option{pattern} options. If such options are
9012 not specified an initial state is created randomly.
9014 At each new frame a new row in the video is filled with the result of
9015 the cellular automaton next generation. The behavior when the whole
9016 frame is filled is defined by the @option{scroll} option.
9018 This source accepts the following options:
9022 Read the initial cellular automaton state, i.e. the starting row, from
9024 In the file, each non-whitespace character is considered an alive
9025 cell, a newline will terminate the row, and further characters in the
9026 file will be ignored.
9029 Read the initial cellular automaton state, i.e. the starting row, from
9030 the specified string.
9032 Each non-whitespace character in the string is considered an alive
9033 cell, a newline will terminate the row, and further characters in the
9034 string will be ignored.
9037 Set the video rate, that is the number of frames generated per second.
9040 @item random_fill_ratio, ratio
9041 Set the random fill ratio for the initial cellular automaton row. It
9042 is a floating point number value ranging from 0 to 1, defaults to
9045 This option is ignored when a file or a pattern is specified.
9047 @item random_seed, seed
9048 Set the seed for filling randomly the initial row, must be an integer
9049 included between 0 and UINT32_MAX. If not specified, or if explicitly
9050 set to -1, the filter will try to use a good random seed on a best
9054 Set the cellular automaton rule, it is a number ranging from 0 to 255.
9055 Default value is 110.
9058 Set the size of the output video. For the syntax of this option, check
9059 the "Video size" section in the ffmpeg-utils manual.
9061 If @option{filename} or @option{pattern} is specified, the size is set
9062 by default to the width of the specified initial state row, and the
9063 height is set to @var{width} * PHI.
9065 If @option{size} is set, it must contain the width of the specified
9066 pattern string, and the specified pattern will be centered in the
9069 If a filename or a pattern string is not specified, the size value
9070 defaults to "320x518" (used for a randomly generated initial state).
9073 If set to 1, scroll the output upward when all the rows in the output
9074 have been already filled. If set to 0, the new generated row will be
9075 written over the top row just after the bottom row is filled.
9078 @item start_full, full
9079 If set to 1, completely fill the output with generated rows before
9080 outputting the first frame.
9081 This is the default behavior, for disabling set the value to 0.
9084 If set to 1, stitch the left and right row edges together.
9085 This is the default behavior, for disabling set the value to 0.
9088 @subsection Examples
9092 Read the initial state from @file{pattern}, and specify an output of
9095 cellauto=f=pattern:s=200x400
9099 Generate a random initial row with a width of 200 cells, with a fill
9102 cellauto=ratio=2/3:s=200x200
9106 Create a pattern generated by rule 18 starting by a single alive cell
9107 centered on an initial row with width 100:
9109 cellauto=p=@@:s=100x400:full=0:rule=18
9113 Specify a more elaborated initial pattern:
9115 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
9122 Generate a Mandelbrot set fractal, and progressively zoom towards the
9123 point specified with @var{start_x} and @var{start_y}.
9125 This source accepts the following options:
9130 Set the terminal pts value. Default value is 400.
9133 Set the terminal scale value.
9134 Must be a floating point value. Default value is 0.3.
9137 Set the inner coloring mode, that is the algorithm used to draw the
9138 Mandelbrot fractal internal region.
9140 It shall assume one of the following values:
9145 Show time until convergence.
9147 Set color based on point closest to the origin of the iterations.
9152 Default value is @var{mincol}.
9155 Set the bailout value. Default value is 10.0.
9158 Set the maximum of iterations performed by the rendering
9159 algorithm. Default value is 7189.
9162 Set outer coloring mode.
9163 It shall assume one of following values:
9165 @item iteration_count
9166 Set iteration cound mode.
9167 @item normalized_iteration_count
9168 set normalized iteration count mode.
9170 Default value is @var{normalized_iteration_count}.
9173 Set frame rate, expressed as number of frames per second. Default
9177 Set frame size. For the syntax of this option, check the "Video
9178 size" section in the ffmpeg-utils manual. Default value is "640x480".
9181 Set the initial scale value. Default value is 3.0.
9184 Set the initial x position. Must be a floating point value between
9185 -100 and 100. Default value is -0.743643887037158704752191506114774.
9188 Set the initial y position. Must be a floating point value between
9189 -100 and 100. Default value is -0.131825904205311970493132056385139.
9194 Generate various test patterns, as generated by the MPlayer test filter.
9196 The size of the generated video is fixed, and is 256x256.
9197 This source is useful in particular for testing encoding features.
9199 This source accepts the following options:
9204 Specify the frame rate of the sourced video, as the number of frames
9205 generated per second. It has to be a string in the format
9206 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9207 number or a valid video frame rate abbreviation. The default value is
9211 Set the video duration of the sourced video. The accepted syntax is:
9216 See also the function @code{av_parse_time()}.
9218 If not specified, or the expressed duration is negative, the video is
9219 supposed to be generated forever.
9223 Set the number or the name of the test to perform. Supported tests are:
9239 Default value is "all", which will cycle through the list of all tests.
9247 will generate a "dc_luma" test pattern.
9251 Provide a frei0r source.
9253 To enable compilation of this filter you need to install the frei0r
9254 header and configure FFmpeg with @code{--enable-frei0r}.
9256 This source accepts the following parameters:
9261 The size of the video to generate. For the syntax of this option, check the
9262 "Video size" section in the ffmpeg-utils manual.
9265 The framerate of the generated video. It may be a string of the form
9266 @var{num}/@var{den} or a frame rate abbreviation.
9269 The name to the frei0r source to load. For more information regarding frei0r and
9270 how to set the parameters, read the @ref{frei0r} section in the video filters
9274 A '|'-separated list of parameters to pass to the frei0r source.
9278 For example, to generate a frei0r partik0l source with size 200x200
9279 and frame rate 10 which is overlayed on the overlay filter main input:
9281 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
9286 Generate a life pattern.
9288 This source is based on a generalization of John Conway's life game.
9290 The sourced input represents a life grid, each pixel represents a cell
9291 which can be in one of two possible states, alive or dead. Every cell
9292 interacts with its eight neighbours, which are the cells that are
9293 horizontally, vertically, or diagonally adjacent.
9295 At each interaction the grid evolves according to the adopted rule,
9296 which specifies the number of neighbor alive cells which will make a
9297 cell stay alive or born. The @option{rule} option allows one to specify
9300 This source accepts the following options:
9304 Set the file from which to read the initial grid state. In the file,
9305 each non-whitespace character is considered an alive cell, and newline
9306 is used to delimit the end of each row.
9308 If this option is not specified, the initial grid is generated
9312 Set the video rate, that is the number of frames generated per second.
9315 @item random_fill_ratio, ratio
9316 Set the random fill ratio for the initial random grid. It is a
9317 floating point number value ranging from 0 to 1, defaults to 1/PHI.
9318 It is ignored when a file is specified.
9320 @item random_seed, seed
9321 Set the seed for filling the initial random grid, must be an integer
9322 included between 0 and UINT32_MAX. If not specified, or if explicitly
9323 set to -1, the filter will try to use a good random seed on a best
9329 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
9330 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
9331 @var{NS} specifies the number of alive neighbor cells which make a
9332 live cell stay alive, and @var{NB} the number of alive neighbor cells
9333 which make a dead cell to become alive (i.e. to "born").
9334 "s" and "b" can be used in place of "S" and "B", respectively.
9336 Alternatively a rule can be specified by an 18-bits integer. The 9
9337 high order bits are used to encode the next cell state if it is alive
9338 for each number of neighbor alive cells, the low order bits specify
9339 the rule for "borning" new cells. Higher order bits encode for an
9340 higher number of neighbor cells.
9341 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
9342 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
9344 Default value is "S23/B3", which is the original Conway's game of life
9345 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
9346 cells, and will born a new cell if there are three alive cells around
9350 Set the size of the output video. For the syntax of this option, check the
9351 "Video size" section in the ffmpeg-utils manual.
9353 If @option{filename} is specified, the size is set by default to the
9354 same size of the input file. If @option{size} is set, it must contain
9355 the size specified in the input file, and the initial grid defined in
9356 that file is centered in the larger resulting area.
9358 If a filename is not specified, the size value defaults to "320x240"
9359 (used for a randomly generated initial grid).
9362 If set to 1, stitch the left and right grid edges together, and the
9363 top and bottom edges also. Defaults to 1.
9366 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
9367 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
9368 value from 0 to 255.
9371 Set the color of living (or new born) cells.
9374 Set the color of dead cells. If @option{mold} is set, this is the first color
9375 used to represent a dead cell.
9378 Set mold color, for definitely dead and moldy cells.
9380 For the syntax of these 3 color options, check the "Color" section in the
9381 ffmpeg-utils manual.
9384 @subsection Examples
9388 Read a grid from @file{pattern}, and center it on a grid of size
9391 life=f=pattern:s=300x300
9395 Generate a random grid of size 200x200, with a fill ratio of 2/3:
9397 life=ratio=2/3:s=200x200
9401 Specify a custom rule for evolving a randomly generated grid:
9407 Full example with slow death effect (mold) using @command{ffplay}:
9409 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
9414 @anchor{haldclutsrc}
9418 @anchor{smptehdbars}
9420 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
9422 The @code{color} source provides an uniformly colored input.
9424 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
9425 @ref{haldclut} filter.
9427 The @code{nullsrc} source returns unprocessed video frames. It is
9428 mainly useful to be employed in analysis / debugging tools, or as the
9429 source for filters which ignore the input data.
9431 The @code{rgbtestsrc} source generates an RGB test pattern useful for
9432 detecting RGB vs BGR issues. You should see a red, green and blue
9433 stripe from top to bottom.
9435 The @code{smptebars} source generates a color bars pattern, based on
9436 the SMPTE Engineering Guideline EG 1-1990.
9438 The @code{smptehdbars} source generates a color bars pattern, based on
9439 the SMPTE RP 219-2002.
9441 The @code{testsrc} source generates a test video pattern, showing a
9442 color pattern, a scrolling gradient and a timestamp. This is mainly
9443 intended for testing purposes.
9445 The sources accept the following parameters:
9450 Specify the color of the source, only available in the @code{color}
9451 source. For the syntax of this option, check the "Color" section in the
9452 ffmpeg-utils manual.
9455 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
9456 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
9457 pixels to be used as identity matrix for 3D lookup tables. Each component is
9458 coded on a @code{1/(N*N)} scale.
9461 Specify the size of the sourced video. For the syntax of this option, check the
9462 "Video size" section in the ffmpeg-utils manual. The default value is
9465 This option is not available with the @code{haldclutsrc} filter.
9468 Specify the frame rate of the sourced video, as the number of frames
9469 generated per second. It has to be a string in the format
9470 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9471 number or a valid video frame rate abbreviation. The default value is
9475 Set the sample aspect ratio of the sourced video.
9478 Set the video duration of the sourced video. The accepted syntax is:
9480 [-]HH[:MM[:SS[.m...]]]
9483 Also see the the @code{av_parse_time()} function.
9485 If not specified, or the expressed duration is negative, the video is
9486 supposed to be generated forever.
9489 Set the number of decimals to show in the timestamp, only available in the
9490 @code{testsrc} source.
9492 The displayed timestamp value will correspond to the original
9493 timestamp value multiplied by the power of 10 of the specified
9494 value. Default value is 0.
9497 For example the following:
9499 testsrc=duration=5.3:size=qcif:rate=10
9502 will generate a video with a duration of 5.3 seconds, with size
9503 176x144 and a frame rate of 10 frames per second.
9505 The following graph description will generate a red source
9506 with an opacity of 0.2, with size "qcif" and a frame rate of 10
9509 color=c=red@@0.2:s=qcif:r=10
9512 If the input content is to be ignored, @code{nullsrc} can be used. The
9513 following command generates noise in the luminance plane by employing
9514 the @code{geq} filter:
9516 nullsrc=s=256x256, geq=random(1)*255:128:128
9519 @subsection Commands
9521 The @code{color} source supports the following commands:
9525 Set the color of the created image. Accepts the same syntax of the
9526 corresponding @option{color} option.
9529 @c man end VIDEO SOURCES
9531 @chapter Video Sinks
9532 @c man begin VIDEO SINKS
9534 Below is a description of the currently available video sinks.
9538 Buffer video frames, and make them available to the end of the filter
9541 This sink is mainly intended for programmatic use, in particular
9542 through the interface defined in @file{libavfilter/buffersink.h}
9543 or the options system.
9545 It accepts a pointer to an AVBufferSinkContext structure, which
9546 defines the incoming buffers' formats, to be passed as the opaque
9547 parameter to @code{avfilter_init_filter} for initialization.
9551 Null video sink: do absolutely nothing with the input video. It is
9552 mainly useful as a template and for use in analysis / debugging
9555 @c man end VIDEO SINKS
9557 @chapter Multimedia Filters
9558 @c man begin MULTIMEDIA FILTERS
9560 Below is a description of the currently available multimedia filters.
9562 @section avectorscope
9564 Convert input audio to a video output, representing the audio vector
9567 The filter is used to measure the difference between channels of stereo
9568 audio stream. A monoaural signal, consisting of identical left and right
9569 signal, results in straight vertical line. Any stereo separation is visible
9570 as a deviation from this line, creating a Lissajous figure.
9571 If the straight (or deviation from it) but horizontal line appears this
9572 indicates that the left and right channels are out of phase.
9574 The filter accepts the following options:
9578 Set the vectorscope mode.
9580 Available values are:
9583 Lissajous rotated by 45 degrees.
9586 Same as above but not rotated.
9589 Default value is @samp{lissajous}.
9592 Set the video size for the output. For the syntax of this option, check the "Video size"
9593 section in the ffmpeg-utils manual. Default value is @code{400x400}.
9596 Set the output frame rate. Default value is @code{25}.
9601 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
9602 Allowed range is @code{[0, 255]}.
9607 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
9608 Allowed range is @code{[0, 255]}.
9611 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
9614 @subsection Examples
9618 Complete example using @command{ffplay}:
9620 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9621 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
9627 Concatenate audio and video streams, joining them together one after the
9630 The filter works on segments of synchronized video and audio streams. All
9631 segments must have the same number of streams of each type, and that will
9632 also be the number of streams at output.
9634 The filter accepts the following options:
9639 Set the number of segments. Default is 2.
9642 Set the number of output video streams, that is also the number of video
9643 streams in each segment. Default is 1.
9646 Set the number of output audio streams, that is also the number of audio
9647 streams in each segment. Default is 0.
9650 Activate unsafe mode: do not fail if segments have a different format.
9654 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
9655 @var{a} audio outputs.
9657 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
9658 segment, in the same order as the outputs, then the inputs for the second
9661 Related streams do not always have exactly the same duration, for various
9662 reasons including codec frame size or sloppy authoring. For that reason,
9663 related synchronized streams (e.g. a video and its audio track) should be
9664 concatenated at once. The concat filter will use the duration of the longest
9665 stream in each segment (except the last one), and if necessary pad shorter
9666 audio streams with silence.
9668 For this filter to work correctly, all segments must start at timestamp 0.
9670 All corresponding streams must have the same parameters in all segments; the
9671 filtering system will automatically select a common pixel format for video
9672 streams, and a common sample format, sample rate and channel layout for
9673 audio streams, but other settings, such as resolution, must be converted
9674 explicitly by the user.
9676 Different frame rates are acceptable but will result in variable frame rate
9677 at output; be sure to configure the output file to handle it.
9679 @subsection Examples
9683 Concatenate an opening, an episode and an ending, all in bilingual version
9684 (video in stream 0, audio in streams 1 and 2):
9686 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
9687 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
9688 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
9689 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
9693 Concatenate two parts, handling audio and video separately, using the
9694 (a)movie sources, and adjusting the resolution:
9696 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
9697 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
9698 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
9700 Note that a desync will happen at the stitch if the audio and video streams
9701 do not have exactly the same duration in the first file.
9707 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
9708 it unchanged. By default, it logs a message at a frequency of 10Hz with the
9709 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
9710 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
9712 The filter also has a video output (see the @var{video} option) with a real
9713 time graph to observe the loudness evolution. The graphic contains the logged
9714 message mentioned above, so it is not printed anymore when this option is set,
9715 unless the verbose logging is set. The main graphing area contains the
9716 short-term loudness (3 seconds of analysis), and the gauge on the right is for
9717 the momentary loudness (400 milliseconds).
9719 More information about the Loudness Recommendation EBU R128 on
9720 @url{http://tech.ebu.ch/loudness}.
9722 The filter accepts the following options:
9727 Activate the video output. The audio stream is passed unchanged whether this
9728 option is set or no. The video stream will be the first output stream if
9729 activated. Default is @code{0}.
9732 Set the video size. This option is for video only. For the syntax of this
9733 option, check the "Video size" section in the ffmpeg-utils manual. Default
9734 and minimum resolution is @code{640x480}.
9737 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
9738 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
9739 other integer value between this range is allowed.
9742 Set metadata injection. If set to @code{1}, the audio input will be segmented
9743 into 100ms output frames, each of them containing various loudness information
9744 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
9746 Default is @code{0}.
9749 Force the frame logging level.
9751 Available values are:
9754 information logging level
9756 verbose logging level
9759 By default, the logging level is set to @var{info}. If the @option{video} or
9760 the @option{metadata} options are set, it switches to @var{verbose}.
9765 Available modes can be cumulated (the option is a @code{flag} type). Possible
9769 Disable any peak mode (default).
9771 Enable sample-peak mode.
9773 Simple peak mode looking for the higher sample value. It logs a message
9774 for sample-peak (identified by @code{SPK}).
9776 Enable true-peak mode.
9778 If enabled, the peak lookup is done on an over-sampled version of the input
9779 stream for better peak accuracy. It logs a message for true-peak.
9780 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
9781 This mode requires a build with @code{libswresample}.
9786 @subsection Examples
9790 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
9792 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
9796 Run an analysis with @command{ffmpeg}:
9798 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
9802 @section interleave, ainterleave
9804 Temporally interleave frames from several inputs.
9806 @code{interleave} works with video inputs, @code{ainterleave} with audio.
9808 These filters read frames from several inputs and send the oldest
9809 queued frame to the output.
9811 Input streams must have a well defined, monotonically increasing frame
9814 In order to submit one frame to output, these filters need to enqueue
9815 at least one frame for each input, so they cannot work in case one
9816 input is not yet terminated and will not receive incoming frames.
9818 For example consider the case when one input is a @code{select} filter
9819 which always drop input frames. The @code{interleave} filter will keep
9820 reading from that input, but it will never be able to send new frames
9821 to output until the input will send an end-of-stream signal.
9823 Also, depending on inputs synchronization, the filters will drop
9824 frames in case one input receives more frames than the other ones, and
9825 the queue is already filled.
9827 These filters accept the following options:
9831 Set the number of different inputs, it is 2 by default.
9834 @subsection Examples
9838 Interleave frames belonging to different streams using @command{ffmpeg}:
9840 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
9844 Add flickering blur effect:
9846 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
9850 @section perms, aperms
9852 Set read/write permissions for the output frames.
9854 These filters are mainly aimed at developers to test direct path in the
9855 following filter in the filtergraph.
9857 The filters accept the following options:
9861 Select the permissions mode.
9863 It accepts the following values:
9866 Do nothing. This is the default.
9868 Set all the output frames read-only.
9870 Set all the output frames directly writable.
9872 Make the frame read-only if writable, and writable if read-only.
9874 Set each output frame read-only or writable randomly.
9878 Set the seed for the @var{random} mode, must be an integer included between
9879 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
9880 @code{-1}, the filter will try to use a good random seed on a best effort
9884 Note: in case of auto-inserted filter between the permission filter and the
9885 following one, the permission might not be received as expected in that
9886 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
9887 perms/aperms filter can avoid this problem.
9889 @section select, aselect
9891 Select frames to pass in output.
9893 This filter accepts the following options:
9898 Set expression, which is evaluated for each input frame.
9900 If the expression is evaluated to zero, the frame is discarded.
9902 If the evaluation result is negative or NaN, the frame is sent to the
9903 first output; otherwise it is sent to the output with index
9904 @code{ceil(val)-1}, assuming that the input index starts from 0.
9906 For example a value of @code{1.2} corresponds to the output with index
9907 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
9910 Set the number of outputs. The output to which to send the selected
9911 frame is based on the result of the evaluation. Default value is 1.
9914 The expression can contain the following constants:
9918 The (sequential) number of the filtered frame, starting from 0.
9921 The (sequential) number of the selected frame, starting from 0.
9923 @item prev_selected_n
9924 The sequential number of the last selected frame. It's NAN if undefined.
9927 The timebase of the input timestamps.
9930 The PTS (Presentation TimeStamp) of the filtered video frame,
9931 expressed in @var{TB} units. It's NAN if undefined.
9934 The PTS of the filtered video frame,
9935 expressed in seconds. It's NAN if undefined.
9938 The PTS of the previously filtered video frame. It's NAN if undefined.
9940 @item prev_selected_pts
9941 The PTS of the last previously filtered video frame. It's NAN if undefined.
9943 @item prev_selected_t
9944 The PTS of the last previously selected video frame. It's NAN if undefined.
9947 The PTS of the first video frame in the video. It's NAN if undefined.
9950 The time of the first video frame in the video. It's NAN if undefined.
9952 @item pict_type @emph{(video only)}
9953 The type of the filtered frame. It can assume one of the following
9965 @item interlace_type @emph{(video only)}
9966 The frame interlace type. It can assume one of the following values:
9969 The frame is progressive (not interlaced).
9971 The frame is top-field-first.
9973 The frame is bottom-field-first.
9976 @item consumed_sample_n @emph{(audio only)}
9977 the number of selected samples before the current frame
9979 @item samples_n @emph{(audio only)}
9980 the number of samples in the current frame
9982 @item sample_rate @emph{(audio only)}
9983 the input sample rate
9986 This is 1 if the filtered frame is a key-frame, 0 otherwise.
9989 the position in the file of the filtered frame, -1 if the information
9990 is not available (e.g. for synthetic video)
9992 @item scene @emph{(video only)}
9993 value between 0 and 1 to indicate a new scene; a low value reflects a low
9994 probability for the current frame to introduce a new scene, while a higher
9995 value means the current frame is more likely to be one (see the example below)
9999 The default value of the select expression is "1".
10001 @subsection Examples
10005 Select all frames in input:
10010 The example above is the same as:
10022 Select only I-frames:
10024 select='eq(pict_type\,I)'
10028 Select one frame every 100:
10030 select='not(mod(n\,100))'
10034 Select only frames contained in the 10-20 time interval:
10036 select=between(t\,10\,20)
10040 Select only I frames contained in the 10-20 time interval:
10042 select=between(t\,10\,20)*eq(pict_type\,I)
10046 Select frames with a minimum distance of 10 seconds:
10048 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
10052 Use aselect to select only audio frames with samples number > 100:
10054 aselect='gt(samples_n\,100)'
10058 Create a mosaic of the first scenes:
10060 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
10063 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
10067 Send even and odd frames to separate outputs, and compose them:
10069 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
10073 @section sendcmd, asendcmd
10075 Send commands to filters in the filtergraph.
10077 These filters read commands to be sent to other filters in the
10080 @code{sendcmd} must be inserted between two video filters,
10081 @code{asendcmd} must be inserted between two audio filters, but apart
10082 from that they act the same way.
10084 The specification of commands can be provided in the filter arguments
10085 with the @var{commands} option, or in a file specified by the
10086 @var{filename} option.
10088 These filters accept the following options:
10091 Set the commands to be read and sent to the other filters.
10093 Set the filename of the commands to be read and sent to the other
10097 @subsection Commands syntax
10099 A commands description consists of a sequence of interval
10100 specifications, comprising a list of commands to be executed when a
10101 particular event related to that interval occurs. The occurring event
10102 is typically the current frame time entering or leaving a given time
10105 An interval is specified by the following syntax:
10107 @var{START}[-@var{END}] @var{COMMANDS};
10110 The time interval is specified by the @var{START} and @var{END} times.
10111 @var{END} is optional and defaults to the maximum time.
10113 The current frame time is considered within the specified interval if
10114 it is included in the interval [@var{START}, @var{END}), that is when
10115 the time is greater or equal to @var{START} and is lesser than
10118 @var{COMMANDS} consists of a sequence of one or more command
10119 specifications, separated by ",", relating to that interval. The
10120 syntax of a command specification is given by:
10122 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
10125 @var{FLAGS} is optional and specifies the type of events relating to
10126 the time interval which enable sending the specified command, and must
10127 be a non-null sequence of identifier flags separated by "+" or "|" and
10128 enclosed between "[" and "]".
10130 The following flags are recognized:
10133 The command is sent when the current frame timestamp enters the
10134 specified interval. In other words, the command is sent when the
10135 previous frame timestamp was not in the given interval, and the
10139 The command is sent when the current frame timestamp leaves the
10140 specified interval. In other words, the command is sent when the
10141 previous frame timestamp was in the given interval, and the
10145 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
10148 @var{TARGET} specifies the target of the command, usually the name of
10149 the filter class or a specific filter instance name.
10151 @var{COMMAND} specifies the name of the command for the target filter.
10153 @var{ARG} is optional and specifies the optional list of argument for
10154 the given @var{COMMAND}.
10156 Between one interval specification and another, whitespaces, or
10157 sequences of characters starting with @code{#} until the end of line,
10158 are ignored and can be used to annotate comments.
10160 A simplified BNF description of the commands specification syntax
10163 @var{COMMAND_FLAG} ::= "enter" | "leave"
10164 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
10165 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
10166 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
10167 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
10168 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
10171 @subsection Examples
10175 Specify audio tempo change at second 4:
10177 asendcmd=c='4.0 atempo tempo 1.5',atempo
10181 Specify a list of drawtext and hue commands in a file.
10183 # show text in the interval 5-10
10184 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
10185 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
10187 # desaturate the image in the interval 15-20
10188 15.0-20.0 [enter] hue s 0,
10189 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
10191 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
10193 # apply an exponential saturation fade-out effect, starting from time 25
10194 25 [enter] hue s exp(25-t)
10197 A filtergraph allowing to read and process the above command list
10198 stored in a file @file{test.cmd}, can be specified with:
10200 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
10205 @section setpts, asetpts
10207 Change the PTS (presentation timestamp) of the input frames.
10209 @code{setpts} works on video frames, @code{asetpts} on audio frames.
10211 This filter accepts the following options:
10216 The expression which is evaluated for each frame to construct its timestamp.
10220 The expression is evaluated through the eval API and can contain the following
10225 frame rate, only defined for constant frame-rate video
10228 The presentation timestamp in input
10231 The count of the input frame for video or the number of consumed samples,
10232 not including the current frame for audio, starting from 0.
10234 @item NB_CONSUMED_SAMPLES
10235 The number of consumed samples, not including the current frame (only
10238 @item NB_SAMPLES, S
10239 The number of samples in the current frame (only audio)
10241 @item SAMPLE_RATE, SR
10242 The audio sample rate.
10245 The PTS of the first frame.
10248 the time in seconds of the first frame
10251 State whether the current frame is interlaced.
10254 the time in seconds of the current frame
10257 original position in the file of the frame, or undefined if undefined
10258 for the current frame
10261 The previous input PTS.
10264 previous input time in seconds
10267 The previous output PTS.
10270 previous output time in seconds
10273 The wallclock (RTC) time in microseconds.. This is deprecated, use time(0)
10277 The wallclock (RTC) time at the start of the movie in microseconds.
10280 The timebase of the input timestamps.
10284 @subsection Examples
10288 Start counting PTS from zero
10290 setpts=PTS-STARTPTS
10294 Apply fast motion effect:
10300 Apply slow motion effect:
10306 Set fixed rate of 25 frames per second:
10312 Set fixed rate 25 fps with some jitter:
10314 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
10318 Apply an offset of 10 seconds to the input PTS:
10324 Generate timestamps from a "live source" and rebase onto the current timebase:
10326 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
10330 Generate timestamps by counting samples:
10337 @section settb, asettb
10339 Set the timebase to use for the output frames timestamps.
10340 It is mainly useful for testing timebase configuration.
10342 It accepts the following parameters:
10347 The expression which is evaluated into the output timebase.
10351 The value for @option{tb} is an arithmetic expression representing a
10352 rational. The expression can contain the constants "AVTB" (the default
10353 timebase), "intb" (the input timebase) and "sr" (the sample rate,
10354 audio only). Default value is "intb".
10356 @subsection Examples
10360 Set the timebase to 1/25:
10366 Set the timebase to 1/10:
10372 Set the timebase to 1001/1000:
10378 Set the timebase to 2*intb:
10384 Set the default timebase value:
10391 +Convert input audio to a video output representing
10392 frequency spectrum logarithmically (using constant Q transform with
10393 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
10395 The filter accepts the following options:
10399 Specify the transform volume (multiplier). Acceptable value is [1.0, 100.0].
10400 Default value is @code{16.0}.
10403 Specify the transform timeclamp. At low frequency, there is trade-off between
10404 accuracy in time domain and frequency domain. If timeclamp is lower,
10405 event in time domain is represented more accurately (such as fast bass drum),
10406 otherwise event in frequency domain is represented more accurately
10407 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
10410 Specify the transform coeffclamp. If coeffclamp is lower, transform is
10411 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
10412 Default value is @code{1.0}.
10415 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
10416 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
10417 Default value is @code{3.0}.
10420 If set to 1 (the default), the video size is 1920x1080 (full HD),
10421 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
10424 Specify video fps. Default value is @code{25}.
10427 Specify number of transform per frame, so there are fps*count transforms
10428 per second. Note tha audio data rate must be divisible by fps*count.
10429 Default value is @code{6}.
10433 @subsection Examples
10437 Playing audio while showing the spectrum:
10439 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
10443 Same as above, but with frame rate 30 fps:
10445 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
10449 Playing at 960x540 and lower CPU usage:
10451 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
10455 A1 and its harmonics: A1, A2, (near)E3, A3:
10457 ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
10458 asplit[a][out1]; [a] showcqt [out0]'
10462 Same as above, but with more accuracy in frequency domain (and slower):
10464 ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
10465 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
10470 @section showspectrum
10472 Convert input audio to a video output, representing the audio frequency
10475 The filter accepts the following options:
10479 Specify the video size for the output. For the syntax of this option, check
10480 the "Video size" section in the ffmpeg-utils manual. Default value is
10484 Specify if the spectrum should slide along the window. Default value is
10488 Specify display mode.
10490 It accepts the following values:
10493 all channels are displayed in the same row
10495 all channels are displayed in separate rows
10498 Default value is @samp{combined}.
10501 Specify display color mode.
10503 It accepts the following values:
10506 each channel is displayed in a separate color
10508 each channel is is displayed using the same color scheme
10511 Default value is @samp{channel}.
10514 Specify scale used for calculating intensity color values.
10516 It accepts the following values:
10521 square root, default
10528 Default value is @samp{sqrt}.
10531 Set saturation modifier for displayed colors. Negative values provide
10532 alternative color scheme. @code{0} is no saturation at all.
10533 Saturation must be in [-10.0, 10.0] range.
10534 Default value is @code{1}.
10537 Set window function.
10539 It accepts the following values:
10542 No samples pre-processing (do not expect this to be faster)
10551 Default value is @code{hann}.
10554 The usage is very similar to the showwaves filter; see the examples in that
10557 @subsection Examples
10561 Large window with logarithmic color scaling:
10563 showspectrum=s=1280x480:scale=log
10567 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
10569 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10570 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
10576 Convert input audio to a video output, representing the samples waves.
10578 The filter accepts the following options:
10582 Specify the video size for the output. For the syntax of this option, check
10583 the "Video size" section in the ffmpeg-utils manual. Default value
10589 Available values are:
10592 Draw a point for each sample.
10595 Draw a vertical line for each sample.
10598 Default value is @code{point}.
10601 Set the number of samples which are printed on the same column. A
10602 larger value will decrease the frame rate. Must be a positive
10603 integer. This option can be set only if the value for @var{rate}
10604 is not explicitly specified.
10607 Set the (approximate) output frame rate. This is done by setting the
10608 option @var{n}. Default value is "25".
10612 @subsection Examples
10616 Output the input file audio and the corresponding video representation
10619 amovie=a.mp3,asplit[out0],showwaves[out1]
10623 Create a synthetic signal and show it with showwaves, forcing a
10624 frame rate of 30 frames per second:
10626 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
10630 @section split, asplit
10632 Split input into several identical outputs.
10634 @code{asplit} works with audio input, @code{split} with video.
10636 The filter accepts a single parameter which specifies the number of outputs. If
10637 unspecified, it defaults to 2.
10639 @subsection Examples
10643 Create two separate outputs from the same input:
10645 [in] split [out0][out1]
10649 To create 3 or more outputs, you need to specify the number of
10652 [in] asplit=3 [out0][out1][out2]
10656 Create two separate outputs from the same input, one cropped and
10659 [in] split [splitout1][splitout2];
10660 [splitout1] crop=100:100:0:0 [cropout];
10661 [splitout2] pad=200:200:100:100 [padout];
10665 Create 5 copies of the input audio with @command{ffmpeg}:
10667 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
10673 Receive commands sent through a libzmq client, and forward them to
10674 filters in the filtergraph.
10676 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
10677 must be inserted between two video filters, @code{azmq} between two
10680 To enable these filters you need to install the libzmq library and
10681 headers and configure FFmpeg with @code{--enable-libzmq}.
10683 For more information about libzmq see:
10684 @url{http://www.zeromq.org/}
10686 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
10687 receives messages sent through a network interface defined by the
10688 @option{bind_address} option.
10690 The received message must be in the form:
10692 @var{TARGET} @var{COMMAND} [@var{ARG}]
10695 @var{TARGET} specifies the target of the command, usually the name of
10696 the filter class or a specific filter instance name.
10698 @var{COMMAND} specifies the name of the command for the target filter.
10700 @var{ARG} is optional and specifies the optional argument list for the
10701 given @var{COMMAND}.
10703 Upon reception, the message is processed and the corresponding command
10704 is injected into the filtergraph. Depending on the result, the filter
10705 will send a reply to the client, adopting the format:
10707 @var{ERROR_CODE} @var{ERROR_REASON}
10711 @var{MESSAGE} is optional.
10713 @subsection Examples
10715 Look at @file{tools/zmqsend} for an example of a zmq client which can
10716 be used to send commands processed by these filters.
10718 Consider the following filtergraph generated by @command{ffplay}
10720 ffplay -dumpgraph 1 -f lavfi "
10721 color=s=100x100:c=red [l];
10722 color=s=100x100:c=blue [r];
10723 nullsrc=s=200x100, zmq [bg];
10724 [bg][l] overlay [bg+l];
10725 [bg+l][r] overlay=x=100 "
10728 To change the color of the left side of the video, the following
10729 command can be used:
10731 echo Parsed_color_0 c yellow | tools/zmqsend
10734 To change the right side:
10736 echo Parsed_color_1 c pink | tools/zmqsend
10739 @c man end MULTIMEDIA FILTERS
10741 @chapter Multimedia Sources
10742 @c man begin MULTIMEDIA SOURCES
10744 Below is a description of the currently available multimedia sources.
10748 This is the same as @ref{movie} source, except it selects an audio
10754 Read audio and/or video stream(s) from a movie container.
10756 It accepts the following parameters:
10760 The name of the resource to read (not necessarily a file; it can also be a
10761 device or a stream accessed through some protocol).
10763 @item format_name, f
10764 Specifies the format assumed for the movie to read, and can be either
10765 the name of a container or an input device. If not specified, the
10766 format is guessed from @var{movie_name} or by probing.
10768 @item seek_point, sp
10769 Specifies the seek point in seconds. The frames will be output
10770 starting from this seek point. The parameter is evaluated with
10771 @code{av_strtod}, so the numerical value may be suffixed by an IS
10772 postfix. The default value is "0".
10775 Specifies the streams to read. Several streams can be specified,
10776 separated by "+". The source will then have as many outputs, in the
10777 same order. The syntax is explained in the ``Stream specifiers''
10778 section in the ffmpeg manual. Two special names, "dv" and "da" specify
10779 respectively the default (best suited) video and audio stream. Default
10780 is "dv", or "da" if the filter is called as "amovie".
10782 @item stream_index, si
10783 Specifies the index of the video stream to read. If the value is -1,
10784 the most suitable video stream will be automatically selected. The default
10785 value is "-1". Deprecated. If the filter is called "amovie", it will select
10786 audio instead of video.
10789 Specifies how many times to read the stream in sequence.
10790 If the value is less than 1, the stream will be read again and again.
10791 Default value is "1".
10793 Note that when the movie is looped the source timestamps are not
10794 changed, so it will generate non monotonically increasing timestamps.
10797 It allows overlaying a second video on top of the main input of
10798 a filtergraph, as shown in this graph:
10800 input -----------> deltapts0 --> overlay --> output
10803 movie --> scale--> deltapts1 -------+
10805 @subsection Examples
10809 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
10810 on top of the input labelled "in":
10812 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
10813 [in] setpts=PTS-STARTPTS [main];
10814 [main][over] overlay=16:16 [out]
10818 Read from a video4linux2 device, and overlay it on top of the input
10821 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
10822 [in] setpts=PTS-STARTPTS [main];
10823 [main][over] overlay=16:16 [out]
10827 Read the first video stream and the audio stream with id 0x81 from
10828 dvd.vob; the video is connected to the pad named "video" and the audio is
10829 connected to the pad named "audio":
10831 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
10835 @c man end MULTIMEDIA SOURCES