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
1443 Apply a flanging effect to the audio.
1445 The filter accepts the following options:
1449 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
1452 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
1455 Set percentage regeneneration (delayed signal feedback). Range from -95 to 95.
1459 Set percentage of delayed signal mixed with original. Range from 0 to 100.
1463 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
1466 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
1467 Default value is @var{sinusoidal}.
1470 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
1471 Default value is 25.
1474 Set delay-line interpolation, @var{linear} or @var{quadratic}.
1475 Default is @var{linear}.
1480 Apply a high-pass filter with 3dB point frequency.
1481 The filter can be either single-pole, or double-pole (the default).
1482 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1484 The filter accepts the following options:
1488 Set frequency in Hz. Default is 3000.
1491 Set number of poles. Default is 2.
1494 Set method to specify band-width of filter.
1507 Specify the band-width of a filter in width_type units.
1508 Applies only to double-pole filter.
1509 The default is 0.707q and gives a Butterworth response.
1514 Join multiple input streams into one multi-channel stream.
1516 It accepts the following parameters:
1520 The number of input streams. It defaults to 2.
1522 @item channel_layout
1523 The desired output channel layout. It defaults to stereo.
1526 Map channels from inputs to output. The argument is a '|'-separated list of
1527 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1528 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1529 can be either the name of the input channel (e.g. FL for front left) or its
1530 index in the specified input stream. @var{out_channel} is the name of the output
1534 The filter will attempt to guess the mappings when they are not specified
1535 explicitly. It does so by first trying to find an unused matching input channel
1536 and if that fails it picks the first unused input channel.
1538 Join 3 inputs (with properly set channel layouts):
1540 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1543 Build a 5.1 output from 6 single-channel streams:
1545 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1546 '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'
1552 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1554 To enable compilation of this filter you need to configure FFmpeg with
1555 @code{--enable-ladspa}.
1559 Specifies the name of LADSPA plugin library to load. If the environment
1560 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1561 each one of the directories specified by the colon separated list in
1562 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1563 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1564 @file{/usr/lib/ladspa/}.
1567 Specifies the plugin within the library. Some libraries contain only
1568 one plugin, but others contain many of them. If this is not set filter
1569 will list all available plugins within the specified library.
1572 Set the '|' separated list of controls which are zero or more floating point
1573 values that determine the behavior of the loaded plugin (for example delay,
1575 Controls need to be defined using the following syntax:
1576 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1577 @var{valuei} is the value set on the @var{i}-th control.
1578 If @option{controls} is set to @code{help}, all available controls and
1579 their valid ranges are printed.
1581 @item sample_rate, s
1582 Specify the sample rate, default to 44100. Only used if plugin have
1586 Set the number of samples per channel per each output frame, default
1587 is 1024. Only used if plugin have zero inputs.
1590 Set the minimum duration of the sourced audio. See the function
1591 @code{av_parse_time()} for the accepted format, also check the "Time duration"
1592 section in the ffmpeg-utils manual.
1593 Note that the resulting duration may be greater than the specified duration,
1594 as the generated audio is always cut at the end of a complete frame.
1595 If not specified, or the expressed duration is negative, the audio is
1596 supposed to be generated forever.
1597 Only used if plugin have zero inputs.
1601 @subsection Examples
1605 List all available plugins within amp (LADSPA example plugin) library:
1611 List all available controls and their valid ranges for @code{vcf_notch}
1612 plugin from @code{VCF} library:
1614 ladspa=f=vcf:p=vcf_notch:c=help
1618 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1621 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1625 Add reverberation to the audio using TAP-plugins
1626 (Tom's Audio Processing plugins):
1628 ladspa=file=tap_reverb:tap_reverb
1632 Generate white noise, with 0.2 amplitude:
1634 ladspa=file=cmt:noise_source_white:c=c0=.2
1638 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1639 @code{C* Audio Plugin Suite} (CAPS) library:
1641 ladspa=file=caps:Click:c=c1=20'
1645 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1647 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1651 @subsection Commands
1653 This filter supports the following commands:
1656 Modify the @var{N}-th control value.
1658 If the specified value is not valid, it is ignored and prior one is kept.
1663 Apply a low-pass filter with 3dB point frequency.
1664 The filter can be either single-pole or double-pole (the default).
1665 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1667 The filter accepts the following options:
1671 Set frequency in Hz. Default is 500.
1674 Set number of poles. Default is 2.
1677 Set method to specify band-width of filter.
1690 Specify the band-width of a filter in width_type units.
1691 Applies only to double-pole filter.
1692 The default is 0.707q and gives a Butterworth response.
1697 Mix channels with specific gain levels. The filter accepts the output
1698 channel layout followed by a set of channels definitions.
1700 This filter is also designed to remap efficiently the channels of an audio
1703 The filter accepts parameters of the form:
1704 "@var{l}:@var{outdef}:@var{outdef}:..."
1708 output channel layout or number of channels
1711 output channel specification, of the form:
1712 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1715 output channel to define, either a channel name (FL, FR, etc.) or a channel
1716 number (c0, c1, etc.)
1719 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1722 input channel to use, see out_name for details; it is not possible to mix
1723 named and numbered input channels
1726 If the `=' in a channel specification is replaced by `<', then the gains for
1727 that specification will be renormalized so that the total is 1, thus
1728 avoiding clipping noise.
1730 @subsection Mixing examples
1732 For example, if you want to down-mix from stereo to mono, but with a bigger
1733 factor for the left channel:
1735 pan=1:c0=0.9*c0+0.1*c1
1738 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1739 7-channels surround:
1741 pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1744 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1745 that should be preferred (see "-ac" option) unless you have very specific
1748 @subsection Remapping examples
1750 The channel remapping will be effective if, and only if:
1753 @item gain coefficients are zeroes or ones,
1754 @item only one input per channel output,
1757 If all these conditions are satisfied, the filter will notify the user ("Pure
1758 channel mapping detected"), and use an optimized and lossless method to do the
1761 For example, if you have a 5.1 source and want a stereo audio stream by
1762 dropping the extra channels:
1764 pan="stereo: c0=FL : c1=FR"
1767 Given the same source, you can also switch front left and front right channels
1768 and keep the input channel layout:
1770 pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
1773 If the input is a stereo audio stream, you can mute the front left channel (and
1774 still keep the stereo channel layout) with:
1779 Still with a stereo audio stream input, you can copy the right channel in both
1780 front left and right:
1782 pan="stereo: c0=FR : c1=FR"
1787 ReplayGain scanner filter. This filter takes an audio stream as an input and
1788 outputs it unchanged.
1789 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1793 Convert the audio sample format, sample rate and channel layout. It is
1794 not meant to be used directly.
1796 @section silencedetect
1798 Detect silence in an audio stream.
1800 This filter logs a message when it detects that the input audio volume is less
1801 or equal to a noise tolerance value for a duration greater or equal to the
1802 minimum detected noise duration.
1804 The printed times and duration are expressed in seconds.
1806 The filter accepts the following options:
1810 Set silence duration until notification (default is 2 seconds).
1813 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1814 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1817 @subsection Examples
1821 Detect 5 seconds of silence with -50dB noise tolerance:
1823 silencedetect=n=-50dB:d=5
1827 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1828 tolerance in @file{silence.mp3}:
1830 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1836 Boost or cut treble (upper) frequencies of the audio using a two-pole
1837 shelving filter with a response similar to that of a standard
1838 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1840 The filter accepts the following options:
1844 Give the gain at whichever is the lower of ~22 kHz and the
1845 Nyquist frequency. Its useful range is about -20 (for a large cut)
1846 to +20 (for a large boost). Beware of clipping when using a positive gain.
1849 Set the filter's central frequency and so can be used
1850 to extend or reduce the frequency range to be boosted or cut.
1851 The default value is @code{3000} Hz.
1854 Set method to specify band-width of filter.
1867 Determine how steep is the filter's shelf transition.
1872 Adjust the input audio volume.
1874 It accepts the following parameters:
1878 Set audio volume expression.
1880 Output values are clipped to the maximum value.
1882 The output audio volume is given by the relation:
1884 @var{output_volume} = @var{volume} * @var{input_volume}
1887 The default value for @var{volume} is "1.0".
1890 This parameter represents the mathematical precision.
1892 It determines which input sample formats will be allowed, which affects the
1893 precision of the volume scaling.
1897 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
1899 32-bit floating-point; this limits input sample format to FLT. (default)
1901 64-bit floating-point; this limits input sample format to DBL.
1905 Choose the behaviour on encountering ReplayGain side data in input frames.
1909 Remove ReplayGain side data, ignoring its contents (the default).
1912 Ignore ReplayGain side data, but leave it in the frame.
1915 Prefer the track gain, if present.
1918 Prefer the album gain, if present.
1921 @item replaygain_preamp
1922 Pre-amplification gain in dB to apply to the selected replaygain gain.
1924 Default value for @var{replaygain_preamp} is 0.0.
1927 Set when the volume expression is evaluated.
1929 It accepts the following values:
1932 only evaluate expression once during the filter initialization, or
1933 when the @samp{volume} command is sent
1936 evaluate expression for each incoming frame
1939 Default value is @samp{once}.
1942 The volume expression can contain the following parameters.
1946 frame number (starting at zero)
1949 @item nb_consumed_samples
1950 number of samples consumed by the filter
1952 number of samples in the current frame
1954 original frame position in the file
1960 PTS at start of stream
1962 time at start of stream
1968 last set volume value
1971 Note that when @option{eval} is set to @samp{once} only the
1972 @var{sample_rate} and @var{tb} variables are available, all other
1973 variables will evaluate to NAN.
1975 @subsection Commands
1977 This filter supports the following commands:
1980 Modify the volume expression.
1981 The command accepts the same syntax of the corresponding option.
1983 If the specified expression is not valid, it is kept at its current
1985 @item replaygain_noclip
1986 Prevent clipping by limiting the gain applied.
1988 Default value for @var{replaygain_noclip} is 1.
1992 @subsection Examples
1996 Halve the input audio volume:
2000 volume=volume=-6.0206dB
2003 In all the above example the named key for @option{volume} can be
2004 omitted, for example like in:
2010 Increase input audio power by 6 decibels using fixed-point precision:
2012 volume=volume=6dB:precision=fixed
2016 Fade volume after time 10 with an annihilation period of 5 seconds:
2018 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
2022 @section volumedetect
2024 Detect the volume of the input video.
2026 The filter has no parameters. The input is not modified. Statistics about
2027 the volume will be printed in the log when the input stream end is reached.
2029 In particular it will show the mean volume (root mean square), maximum
2030 volume (on a per-sample basis), and the beginning of a histogram of the
2031 registered volume values (from the maximum value to a cumulated 1/1000 of
2034 All volumes are in decibels relative to the maximum PCM value.
2036 @subsection Examples
2038 Here is an excerpt of the output:
2040 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2041 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2042 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2043 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2044 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2045 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2046 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2047 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2048 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2054 The mean square energy is approximately -27 dB, or 10^-2.7.
2056 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2058 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2061 In other words, raising the volume by +4 dB does not cause any clipping,
2062 raising it by +5 dB causes clipping for 6 samples, etc.
2064 @c man end AUDIO FILTERS
2066 @chapter Audio Sources
2067 @c man begin AUDIO SOURCES
2069 Below is a description of the currently available audio sources.
2073 Buffer audio frames, and make them available to the filter chain.
2075 This source is mainly intended for a programmatic use, in particular
2076 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2078 It accepts the following parameters:
2082 The timebase which will be used for timestamps of submitted frames. It must be
2083 either a floating-point number or in @var{numerator}/@var{denominator} form.
2086 The sample rate of the incoming audio buffers.
2089 The sample format of the incoming audio buffers.
2090 Either a sample format name or its corresponging integer representation from
2091 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2093 @item channel_layout
2094 The channel layout of the incoming audio buffers.
2095 Either a channel layout name from channel_layout_map in
2096 @file{libavutil/channel_layout.c} or its corresponding integer representation
2097 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2100 The number of channels of the incoming audio buffers.
2101 If both @var{channels} and @var{channel_layout} are specified, then they
2106 @subsection Examples
2109 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2112 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2113 Since the sample format with name "s16p" corresponds to the number
2114 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2117 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2122 Generate an audio signal specified by an expression.
2124 This source accepts in input one or more expressions (one for each
2125 channel), which are evaluated and used to generate a corresponding
2128 This source accepts the following options:
2132 Set the '|'-separated expressions list for each separate channel. In case the
2133 @option{channel_layout} option is not specified, the selected channel layout
2134 depends on the number of provided expressions. Otherwise the last
2135 specified expression is applied to the remaining output channels.
2137 @item channel_layout, c
2138 Set the channel layout. The number of channels in the specified layout
2139 must be equal to the number of specified expressions.
2142 Set the minimum duration of the sourced audio. See the function
2143 @code{av_parse_time()} for the accepted format.
2144 Note that the resulting duration may be greater than the specified
2145 duration, as the generated audio is always cut at the end of a
2148 If not specified, or the expressed duration is negative, the audio is
2149 supposed to be generated forever.
2152 Set the number of samples per channel per each output frame,
2155 @item sample_rate, s
2156 Specify the sample rate, default to 44100.
2159 Each expression in @var{exprs} can contain the following constants:
2163 number of the evaluated sample, starting from 0
2166 time of the evaluated sample expressed in seconds, starting from 0
2173 @subsection Examples
2183 Generate a sin signal with frequency of 440 Hz, set sample rate to
2186 aevalsrc="sin(440*2*PI*t):s=8000"
2190 Generate a two channels signal, specify the channel layout (Front
2191 Center + Back Center) explicitly:
2193 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2197 Generate white noise:
2199 aevalsrc="-2+random(0)"
2203 Generate an amplitude modulated signal:
2205 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2209 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2211 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2218 The null audio source, return unprocessed audio frames. It is mainly useful
2219 as a template and to be employed in analysis / debugging tools, or as
2220 the source for filters which ignore the input data (for example the sox
2223 This source accepts the following options:
2227 @item channel_layout, cl
2229 Specifies the channel layout, and can be either an integer or a string
2230 representing a channel layout. The default value of @var{channel_layout}
2233 Check the channel_layout_map definition in
2234 @file{libavutil/channel_layout.c} for the mapping between strings and
2235 channel layout values.
2237 @item sample_rate, r
2238 Specifies the sample rate, and defaults to 44100.
2241 Set the number of samples per requested frames.
2245 @subsection Examples
2249 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2251 anullsrc=r=48000:cl=4
2255 Do the same operation with a more obvious syntax:
2257 anullsrc=r=48000:cl=mono
2261 All the parameters need to be explicitly defined.
2265 Synthesize a voice utterance using the libflite library.
2267 To enable compilation of this filter you need to configure FFmpeg with
2268 @code{--enable-libflite}.
2270 Note that the flite library is not thread-safe.
2272 The filter accepts the following options:
2277 If set to 1, list the names of the available voices and exit
2278 immediately. Default value is 0.
2281 Set the maximum number of samples per frame. Default value is 512.
2284 Set the filename containing the text to speak.
2287 Set the text to speak.
2290 Set the voice to use for the speech synthesis. Default value is
2291 @code{kal}. See also the @var{list_voices} option.
2294 @subsection Examples
2298 Read from file @file{speech.txt}, and synthetize the text using the
2299 standard flite voice:
2301 flite=textfile=speech.txt
2305 Read the specified text selecting the @code{slt} voice:
2307 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2311 Input text to ffmpeg:
2313 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2317 Make @file{ffplay} speak the specified text, using @code{flite} and
2318 the @code{lavfi} device:
2320 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2324 For more information about libflite, check:
2325 @url{http://www.speech.cs.cmu.edu/flite/}
2329 Generate an audio signal made of a sine wave with amplitude 1/8.
2331 The audio signal is bit-exact.
2333 The filter accepts the following options:
2338 Set the carrier frequency. Default is 440 Hz.
2340 @item beep_factor, b
2341 Enable a periodic beep every second with frequency @var{beep_factor} times
2342 the carrier frequency. Default is 0, meaning the beep is disabled.
2344 @item sample_rate, r
2345 Specify the sample rate, default is 44100.
2348 Specify the duration of the generated audio stream.
2350 @item samples_per_frame
2351 Set the number of samples per output frame, default is 1024.
2354 @subsection Examples
2359 Generate a simple 440 Hz sine wave:
2365 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2369 sine=frequency=220:beep_factor=4:duration=5
2374 @c man end AUDIO SOURCES
2376 @chapter Audio Sinks
2377 @c man begin AUDIO SINKS
2379 Below is a description of the currently available audio sinks.
2381 @section abuffersink
2383 Buffer audio frames, and make them available to the end of filter chain.
2385 This sink is mainly intended for programmatic use, in particular
2386 through the interface defined in @file{libavfilter/buffersink.h}
2387 or the options system.
2389 It accepts a pointer to an AVABufferSinkContext structure, which
2390 defines the incoming buffers' formats, to be passed as the opaque
2391 parameter to @code{avfilter_init_filter} for initialization.
2394 Null audio sink; do absolutely nothing with the input audio. It is
2395 mainly useful as a template and for use in analysis / debugging
2398 @c man end AUDIO SINKS
2400 @chapter Video Filters
2401 @c man begin VIDEO FILTERS
2403 When you configure your FFmpeg build, you can disable any of the
2404 existing filters using @code{--disable-filters}.
2405 The configure output will show the video filters included in your
2408 Below is a description of the currently available video filters.
2410 @section alphaextract
2412 Extract the alpha component from the input as a grayscale video. This
2413 is especially useful with the @var{alphamerge} filter.
2417 Add or replace the alpha component of the primary input with the
2418 grayscale value of a second input. This is intended for use with
2419 @var{alphaextract} to allow the transmission or storage of frame
2420 sequences that have alpha in a format that doesn't support an alpha
2423 For example, to reconstruct full frames from a normal YUV-encoded video
2424 and a separate video created with @var{alphaextract}, you might use:
2426 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2429 Since this filter is designed for reconstruction, it operates on frame
2430 sequences without considering timestamps, and terminates when either
2431 input reaches end of stream. This will cause problems if your encoding
2432 pipeline drops frames. If you're trying to apply an image as an
2433 overlay to a video stream, consider the @var{overlay} filter instead.
2437 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2438 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2439 Substation Alpha) subtitles files.
2443 Compute the bounding box for the non-black pixels in the input frame
2446 This filter computes the bounding box containing all the pixels with a
2447 luminance value greater than the minimum allowed value.
2448 The parameters describing the bounding box are printed on the filter
2451 The filter accepts the following option:
2455 Set the minimal luminance value. Default is @code{16}.
2458 @section blackdetect
2460 Detect video intervals that are (almost) completely black. Can be
2461 useful to detect chapter transitions, commercials, or invalid
2462 recordings. Output lines contains the time for the start, end and
2463 duration of the detected black interval expressed in seconds.
2465 In order to display the output lines, you need to set the loglevel at
2466 least to the AV_LOG_INFO value.
2468 The filter accepts the following options:
2471 @item black_min_duration, d
2472 Set the minimum detected black duration expressed in seconds. It must
2473 be a non-negative floating point number.
2475 Default value is 2.0.
2477 @item picture_black_ratio_th, pic_th
2478 Set the threshold for considering a picture "black".
2479 Express the minimum value for the ratio:
2481 @var{nb_black_pixels} / @var{nb_pixels}
2484 for which a picture is considered black.
2485 Default value is 0.98.
2487 @item pixel_black_th, pix_th
2488 Set the threshold for considering a pixel "black".
2490 The threshold expresses the maximum pixel luminance value for which a
2491 pixel is considered "black". The provided value is scaled according to
2492 the following equation:
2494 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2497 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2498 the input video format, the range is [0-255] for YUV full-range
2499 formats and [16-235] for YUV non full-range formats.
2501 Default value is 0.10.
2504 The following example sets the maximum pixel threshold to the minimum
2505 value, and detects only black intervals of 2 or more seconds:
2507 blackdetect=d=2:pix_th=0.00
2512 Detect frames that are (almost) completely black. Can be useful to
2513 detect chapter transitions or commercials. Output lines consist of
2514 the frame number of the detected frame, the percentage of blackness,
2515 the position in the file if known or -1 and the timestamp in seconds.
2517 In order to display the output lines, you need to set the loglevel at
2518 least to the AV_LOG_INFO value.
2520 It accepts the following parameters:
2525 The percentage of the pixels that have to be below the threshold; it defaults to
2528 @item threshold, thresh
2529 The threshold below which a pixel value is considered black; it defaults to
2536 Blend two video frames into each other.
2538 It takes two input streams and outputs one stream, the first input is the
2539 "top" layer and second input is "bottom" layer.
2540 Output terminates when shortest input terminates.
2542 A description of the accepted options follows.
2550 Set blend mode for specific pixel component or all pixel components in case
2551 of @var{all_mode}. Default value is @code{normal}.
2553 Available values for component modes are:
2586 Set blend opacity for specific pixel component or all pixel components in case
2587 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2594 Set blend expression for specific pixel component or all pixel components in case
2595 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2597 The expressions can use the following variables:
2601 The sequential number of the filtered frame, starting from @code{0}.
2605 the coordinates of the current sample
2609 the width and height of currently filtered plane
2613 Width and height scale depending on the currently filtered plane. It is the
2614 ratio between the corresponding luma plane number of pixels and the current
2615 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2616 @code{0.5,0.5} for chroma planes.
2619 Time of the current frame, expressed in seconds.
2622 Value of pixel component at current location for first video frame (top layer).
2625 Value of pixel component at current location for second video frame (bottom layer).
2629 Force termination when the shortest input terminates. Default is @code{0}.
2631 Continue applying the last bottom frame after the end of the stream. A value of
2632 @code{0} disable the filter after the last frame of the bottom layer is reached.
2633 Default is @code{1}.
2636 @subsection Examples
2640 Apply transition from bottom layer to top layer in first 10 seconds:
2642 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2646 Apply 1x1 checkerboard effect:
2648 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2652 Apply uncover left effect:
2654 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2658 Apply uncover down effect:
2660 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2664 Apply uncover up-left effect:
2666 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2672 Apply a boxblur algorithm to the input video.
2674 It accepts the following parameters:
2678 @item luma_radius, lr
2679 @item luma_power, lp
2680 @item chroma_radius, cr
2681 @item chroma_power, cp
2682 @item alpha_radius, ar
2683 @item alpha_power, ap
2687 A description of the accepted options follows.
2690 @item luma_radius, lr
2691 @item chroma_radius, cr
2692 @item alpha_radius, ar
2693 Set an expression for the box radius in pixels used for blurring the
2694 corresponding input plane.
2696 The radius value must be a non-negative number, and must not be
2697 greater than the value of the expression @code{min(w,h)/2} for the
2698 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2701 Default value for @option{luma_radius} is "2". If not specified,
2702 @option{chroma_radius} and @option{alpha_radius} default to the
2703 corresponding value set for @option{luma_radius}.
2705 The expressions can contain the following constants:
2709 The input width and height in pixels.
2713 The input chroma image width and height in pixels.
2717 The horizontal and vertical chroma subsample values. For example, for the
2718 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
2721 @item luma_power, lp
2722 @item chroma_power, cp
2723 @item alpha_power, ap
2724 Specify how many times the boxblur filter is applied to the
2725 corresponding plane.
2727 Default value for @option{luma_power} is 2. If not specified,
2728 @option{chroma_power} and @option{alpha_power} default to the
2729 corresponding value set for @option{luma_power}.
2731 A value of 0 will disable the effect.
2734 @subsection Examples
2738 Apply a boxblur filter with the luma, chroma, and alpha radii
2741 boxblur=luma_radius=2:luma_power=1
2746 Set the luma radius to 2, and alpha and chroma radius to 0:
2748 boxblur=2:1:cr=0:ar=0
2752 Set the luma and chroma radii to a fraction of the video dimension:
2754 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2758 @section colorbalance
2759 Modify intensity of primary colors (red, green and blue) of input frames.
2761 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2762 regions for the red-cyan, green-magenta or blue-yellow balance.
2764 A positive adjustment value shifts the balance towards the primary color, a negative
2765 value towards the complementary color.
2767 The filter accepts the following options:
2773 Adjust red, green and blue shadows (darkest pixels).
2778 Adjust red, green and blue midtones (medium pixels).
2783 Adjust red, green and blue highlights (brightest pixels).
2785 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2788 @subsection Examples
2792 Add red color cast to shadows:
2798 @section colorchannelmixer
2800 Adjust video input frames by re-mixing color channels.
2802 This filter modifies a color channel by adding the values associated to
2803 the other channels of the same pixels. For example if the value to
2804 modify is red, the output value will be:
2806 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2809 The filter accepts the following options:
2816 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2817 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2823 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2824 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2830 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2831 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2837 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2838 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2840 Allowed ranges for options are @code{[-2.0, 2.0]}.
2843 @subsection Examples
2847 Convert source to grayscale:
2849 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2852 Simulate sepia tones:
2854 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
2858 @section colormatrix
2860 Convert color matrix.
2862 The filter accepts the following options:
2867 Specify the source and destination color matrix. Both values must be
2870 The accepted values are:
2886 For example to convert from BT.601 to SMPTE-240M, use the command:
2888 colormatrix=bt601:smpte240m
2893 Copy the input source unchanged to the output. This is mainly useful for
2898 Crop the input video to given dimensions.
2900 It accepts the following parameters:
2904 The width of the output video. It defaults to @code{iw}.
2905 This expression is evaluated only once during the filter
2909 The height of the output video. It defaults to @code{ih}.
2910 This expression is evaluated only once during the filter
2914 The horizontal position, in the input video, of the left edge of the output
2915 video. It defaults to @code{(in_w-out_w)/2}.
2916 This expression is evaluated per-frame.
2919 The vertical position, in the input video, of the top edge of the output video.
2920 It defaults to @code{(in_h-out_h)/2}.
2921 This expression is evaluated per-frame.
2924 If set to 1 will force the output display aspect ratio
2925 to be the same of the input, by changing the output sample aspect
2926 ratio. It defaults to 0.
2929 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
2930 expressions containing the following constants:
2935 The computed values for @var{x} and @var{y}. They are evaluated for
2940 The input width and height.
2944 These are the same as @var{in_w} and @var{in_h}.
2948 The output (cropped) width and height.
2952 These are the same as @var{out_w} and @var{out_h}.
2955 same as @var{iw} / @var{ih}
2958 input sample aspect ratio
2961 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
2965 horizontal and vertical chroma subsample values. For example for the
2966 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2969 The number of the input frame, starting from 0.
2972 the position in the file of the input frame, NAN if unknown
2975 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
2979 The expression for @var{out_w} may depend on the value of @var{out_h},
2980 and the expression for @var{out_h} may depend on @var{out_w}, but they
2981 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
2982 evaluated after @var{out_w} and @var{out_h}.
2984 The @var{x} and @var{y} parameters specify the expressions for the
2985 position of the top-left corner of the output (non-cropped) area. They
2986 are evaluated for each frame. If the evaluated value is not valid, it
2987 is approximated to the nearest valid value.
2989 The expression for @var{x} may depend on @var{y}, and the expression
2990 for @var{y} may depend on @var{x}.
2992 @subsection Examples
2996 Crop area with size 100x100 at position (12,34).
3001 Using named options, the example above becomes:
3003 crop=w=100:h=100:x=12:y=34
3007 Crop the central input area with size 100x100:
3013 Crop the central input area with size 2/3 of the input video:
3015 crop=2/3*in_w:2/3*in_h
3019 Crop the input video central square:
3026 Delimit the rectangle with the top-left corner placed at position
3027 100:100 and the right-bottom corner corresponding to the right-bottom
3028 corner of the input image.
3030 crop=in_w-100:in_h-100:100:100
3034 Crop 10 pixels from the left and right borders, and 20 pixels from
3035 the top and bottom borders
3037 crop=in_w-2*10:in_h-2*20
3041 Keep only the bottom right quarter of the input image:
3043 crop=in_w/2:in_h/2:in_w/2:in_h/2
3047 Crop height for getting Greek harmony:
3049 crop=in_w:1/PHI*in_w
3053 Appply trembling effect:
3055 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)
3059 Apply erratic camera effect depending on timestamp:
3061 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)"
3065 Set x depending on the value of y:
3067 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3073 Auto-detect the crop size.
3075 It calculates the necessary cropping parameters and prints the
3076 recommended parameters via the logging system. The detected dimensions
3077 correspond to the non-black area of the input video.
3079 It accepts the following parameters:
3084 Set higher black value threshold, which can be optionally specified
3085 from nothing (0) to everything (255). An intensity value greater
3086 to the set value is considered non-black. It defaults to 24.
3089 The value which the width/height should be divisible by. It defaults to
3090 16. The offset is automatically adjusted to center the video. Use 2 to
3091 get only even dimensions (needed for 4:2:2 video). 16 is best when
3092 encoding to most video codecs.
3094 @item reset_count, reset
3095 Set the counter that determines after how many frames cropdetect will
3096 reset the previously detected largest video area and start over to
3097 detect the current optimal crop area. Default value is 0.
3099 This can be useful when channel logos distort the video area. 0
3100 indicates 'never reset', and returns the largest area encountered during
3107 Apply color adjustments using curves.
3109 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3110 component (red, green and blue) has its values defined by @var{N} key points
3111 tied from each other using a smooth curve. The x-axis represents the pixel
3112 values from the input frame, and the y-axis the new pixel values to be set for
3115 By default, a component curve is defined by the two points @var{(0;0)} and
3116 @var{(1;1)}. This creates a straight line where each original pixel value is
3117 "adjusted" to its own value, which means no change to the image.
3119 The filter allows you to redefine these two points and add some more. A new
3120 curve (using a natural cubic spline interpolation) will be define to pass
3121 smoothly through all these new coordinates. The new defined points needs to be
3122 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3123 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3124 the vector spaces, the values will be clipped accordingly.
3126 If there is no key point defined in @code{x=0}, the filter will automatically
3127 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3128 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3130 The filter accepts the following options:
3134 Select one of the available color presets. This option can be used in addition
3135 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3136 options takes priority on the preset values.
3137 Available presets are:
3140 @item color_negative
3143 @item increase_contrast
3145 @item linear_contrast
3146 @item medium_contrast
3148 @item strong_contrast
3151 Default is @code{none}.
3153 Set the master key points. These points will define a second pass mapping. It
3154 is sometimes called a "luminance" or "value" mapping. It can be used with
3155 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3156 post-processing LUT.
3158 Set the key points for the red component.
3160 Set the key points for the green component.
3162 Set the key points for the blue component.
3164 Set the key points for all components (not including master).
3165 Can be used in addition to the other key points component
3166 options. In this case, the unset component(s) will fallback on this
3167 @option{all} setting.
3169 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3172 To avoid some filtergraph syntax conflicts, each key points list need to be
3173 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3175 @subsection Examples
3179 Increase slightly the middle level of blue:
3181 curves=blue='0.5/0.58'
3187 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3189 Here we obtain the following coordinates for each components:
3192 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3194 @code{(0;0) (0.50;0.48) (1;1)}
3196 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3200 The previous example can also be achieved with the associated built-in preset:
3202 curves=preset=vintage
3212 Use a Photoshop preset and redefine the points of the green component:
3214 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3220 Denoise frames using 2D DCT (frequency domain filtering).
3222 This filter is not designed for real time and can be extremely slow.
3224 The filter accepts the following options:
3228 Set the noise sigma constant.
3230 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3231 coefficient (absolute value) below this threshold with be dropped.
3233 If you need a more advanced filtering, see @option{expr}.
3235 Default is @code{0}.
3238 Set number overlapping pixels for each block. Each block is of size
3239 @code{16x16}. Since the filter can be slow, you may want to reduce this value,
3240 at the cost of a less effective filter and the risk of various artefacts.
3242 If the overlapping value doesn't allow to process the whole input width or
3243 height, a warning will be displayed and according borders won't be denoised.
3245 Default value is @code{15}.
3248 Set the coefficient factor expression.
3250 For each coefficient of a DCT block, this expression will be evaluated as a
3251 multiplier value for the coefficient.
3253 If this is option is set, the @option{sigma} option will be ignored.
3255 The absolute value of the coefficient can be accessed through the @var{c}
3259 @subsection Examples
3261 Apply a denoise with a @option{sigma} of @code{4.5}:
3266 The same operation can be achieved using the expression system:
3268 dctdnoiz=e='gte(c, 4.5*3)'
3274 Drop duplicated frames at regular intervals.
3276 The filter accepts the following options:
3280 Set the number of frames from which one will be dropped. Setting this to
3281 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3282 Default is @code{5}.
3285 Set the threshold for duplicate detection. If the difference metric for a frame
3286 is less than or equal to this value, then it is declared as duplicate. Default
3290 Set scene change threshold. Default is @code{15}.
3294 Set the size of the x and y-axis blocks used during metric calculations.
3295 Larger blocks give better noise suppression, but also give worse detection of
3296 small movements. Must be a power of two. Default is @code{32}.
3299 Mark main input as a pre-processed input and activate clean source input
3300 stream. This allows the input to be pre-processed with various filters to help
3301 the metrics calculation while keeping the frame selection lossless. When set to
3302 @code{1}, the first stream is for the pre-processed input, and the second
3303 stream is the clean source from where the kept frames are chosen. Default is
3307 Set whether or not chroma is considered in the metric calculations. Default is
3313 Remove judder produced by partially interlaced telecined content.
3315 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3316 source was partially telecined content then the output of @code{pullup,dejudder}
3317 will have a variable frame rate. May change the recorded frame rate of the
3318 container. Aside from that change, this filter will not affect constant frame
3321 The option available in this filter is:
3325 Specify the length of the window over which the judder repeats.
3327 Accepts any integer greater than 1. Useful values are:
3331 If the original was telecined from 24 to 30 fps (Film to NTSC).
3334 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3337 If a mixture of the two.
3340 The default is @samp{4}.
3345 Suppress a TV station logo by a simple interpolation of the surrounding
3346 pixels. Just set a rectangle covering the logo and watch it disappear
3347 (and sometimes something even uglier appear - your mileage may vary).
3349 It accepts the following parameters:
3354 Specify the top left corner coordinates of the logo. They must be
3359 Specify the width and height of the logo to clear. They must be
3363 Specify the thickness of the fuzzy edge of the rectangle (added to
3364 @var{w} and @var{h}). The default value is 4.
3367 When set to 1, a green rectangle is drawn on the screen to simplify
3368 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3369 The default value is 0.
3371 The rectangle is drawn on the outermost pixels which will be (partly)
3372 replaced with interpolated values. The values of the next pixels
3373 immediately outside this rectangle in each direction will be used to
3374 compute the interpolated pixel values inside the rectangle.
3378 @subsection Examples
3382 Set a rectangle covering the area with top left corner coordinates 0,0
3383 and size 100x77, and a band of size 10:
3385 delogo=x=0:y=0:w=100:h=77:band=10
3392 Attempt to fix small changes in horizontal and/or vertical shift. This
3393 filter helps remove camera shake from hand-holding a camera, bumping a
3394 tripod, moving on a vehicle, etc.
3396 The filter accepts the following options:
3404 Specify a rectangular area where to limit the search for motion
3406 If desired the search for motion vectors can be limited to a
3407 rectangular area of the frame defined by its top left corner, width
3408 and height. These parameters have the same meaning as the drawbox
3409 filter which can be used to visualise the position of the bounding
3412 This is useful when simultaneous movement of subjects within the frame
3413 might be confused for camera motion by the motion vector search.
3415 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3416 then the full frame is used. This allows later options to be set
3417 without specifying the bounding box for the motion vector search.
3419 Default - search the whole frame.
3423 Specify the maximum extent of movement in x and y directions in the
3424 range 0-64 pixels. Default 16.
3427 Specify how to generate pixels to fill blanks at the edge of the
3428 frame. Available values are:
3431 Fill zeroes at blank locations
3433 Original image at blank locations
3435 Extruded edge value at blank locations
3437 Mirrored edge at blank locations
3439 Default value is @samp{mirror}.
3442 Specify the blocksize to use for motion search. Range 4-128 pixels,
3446 Specify the contrast threshold for blocks. Only blocks with more than
3447 the specified contrast (difference between darkest and lightest
3448 pixels) will be considered. Range 1-255, default 125.
3451 Specify the search strategy. Available values are:
3454 Set exhaustive search
3456 Set less exhaustive search.
3458 Default value is @samp{exhaustive}.
3461 If set then a detailed log of the motion search is written to the
3465 If set to 1, specify using OpenCL capabilities, only available if
3466 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3472 Draw a colored box on the input image.
3474 It accepts the following parameters:
3479 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3483 The expressions which specify the width and height of the box; if 0 they are interpreted as
3484 the input width and height. It defaults to 0.
3487 Specify the color of the box to write. For the general syntax of this option,
3488 check the "Color" section in the ffmpeg-utils manual. If the special
3489 value @code{invert} is used, the box edge color is the same as the
3490 video with inverted luma.
3493 The expression which sets the thickness of the box edge. Default value is @code{3}.
3495 See below for the list of accepted constants.
3498 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3499 following constants:
3503 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3507 horizontal and vertical chroma subsample values. For example for the
3508 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3512 The input width and height.
3515 The input sample aspect ratio.
3519 The x and y offset coordinates where the box is drawn.
3523 The width and height of the drawn box.
3526 The thickness of the drawn box.
3528 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3529 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3533 @subsection Examples
3537 Draw a black box around the edge of the input image:
3543 Draw a box with color red and an opacity of 50%:
3545 drawbox=10:20:200:60:red@@0.5
3548 The previous example can be specified as:
3550 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3554 Fill the box with pink color:
3556 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3560 Draw a 2-pixel red 2.40:1 mask:
3562 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
3568 Draw a grid on the input image.
3570 It accepts the following parameters:
3575 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3579 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3580 input width and height, respectively, minus @code{thickness}, so image gets
3581 framed. Default to 0.
3584 Specify the color of the grid. For the general syntax of this option,
3585 check the "Color" section in the ffmpeg-utils manual. If the special
3586 value @code{invert} is used, the grid color is the same as the
3587 video with inverted luma.
3590 The expression which sets the thickness of the grid line. Default value is @code{1}.
3592 See below for the list of accepted constants.
3595 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3596 following constants:
3600 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3604 horizontal and vertical chroma subsample values. For example for the
3605 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3609 The input grid cell width and height.
3612 The input sample aspect ratio.
3616 The x and y coordinates of some point of grid intersection (meant to configure offset).
3620 The width and height of the drawn cell.
3623 The thickness of the drawn cell.
3625 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3626 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3630 @subsection Examples
3634 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3636 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3640 Draw a white 3x3 grid with an opacity of 50%:
3642 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3649 Draw a text string or text from a specified file on top of a video, using the
3650 libfreetype library.
3652 To enable compilation of this filter, you need to configure FFmpeg with
3653 @code{--enable-libfreetype}.
3654 To enable default font fallback and the @var{font} option you need to
3655 configure FFmpeg with @code{--enable-libfontconfig}.
3659 It accepts the following parameters:
3664 Used to draw a box around text using the background color.
3665 The value must be either 1 (enable) or 0 (disable).
3666 The default value of @var{box} is 0.
3669 The color to be used for drawing box around text. For the syntax of this
3670 option, check the "Color" section in the ffmpeg-utils manual.
3672 The default value of @var{boxcolor} is "white".
3675 Set the width of the border to be drawn around the text using @var{bordercolor}.
3676 The default value of @var{borderw} is 0.
3679 Set the color to be used for drawing border around text. For the syntax of this
3680 option, check the "Color" section in the ffmpeg-utils manual.
3682 The default value of @var{bordercolor} is "black".
3685 Select how the @var{text} is expanded. Can be either @code{none},
3686 @code{strftime} (deprecated) or
3687 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3691 If true, check and fix text coords to avoid clipping.
3694 The color to be used for drawing fonts. For the syntax of this option, check
3695 the "Color" section in the ffmpeg-utils manual.
3697 The default value of @var{fontcolor} is "black".
3700 The font family to be used for drawing text. By default Sans.
3703 The font file to be used for drawing text. The path must be included.
3704 This parameter is mandatory if the fontconfig support is disabled.
3707 The font size to be used for drawing text.
3708 The default value of @var{fontsize} is 16.
3711 The flags to be used for loading the fonts.
3713 The flags map the corresponding flags supported by libfreetype, and are
3714 a combination of the following values:
3721 @item vertical_layout
3722 @item force_autohint
3725 @item ignore_global_advance_width
3727 @item ignore_transform
3733 Default value is "default".
3735 For more information consult the documentation for the FT_LOAD_*
3739 The color to be used for drawing a shadow behind the drawn text. For the
3740 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3742 The default value of @var{shadowcolor} is "black".
3746 The x and y offsets for the text shadow position with respect to the
3747 position of the text. They can be either positive or negative
3748 values. The default value for both is "0".
3751 The starting frame number for the n/frame_num variable. The default value
3755 The size in number of spaces to use for rendering the tab.
3759 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3760 format. It can be used with or without text parameter. @var{timecode_rate}
3761 option must be specified.
3763 @item timecode_rate, rate, r
3764 Set the timecode frame rate (timecode only).
3767 The text string to be drawn. The text must be a sequence of UTF-8
3769 This parameter is mandatory if no file is specified with the parameter
3773 A text file containing text to be drawn. The text must be a sequence
3774 of UTF-8 encoded characters.
3776 This parameter is mandatory if no text string is specified with the
3777 parameter @var{text}.
3779 If both @var{text} and @var{textfile} are specified, an error is thrown.
3782 If set to 1, the @var{textfile} will be reloaded before each frame.
3783 Be sure to update it atomically, or it may be read partially, or even fail.
3787 The expressions which specify the offsets where text will be drawn
3788 within the video frame. They are relative to the top/left border of the
3791 The default value of @var{x} and @var{y} is "0".
3793 See below for the list of accepted constants and functions.
3796 The parameters for @var{x} and @var{y} are expressions containing the
3797 following constants and functions:
3801 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3805 horizontal and vertical chroma subsample values. For example for the
3806 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3809 the height of each text line
3817 @item max_glyph_a, ascent
3818 the maximum distance from the baseline to the highest/upper grid
3819 coordinate used to place a glyph outline point, for all the rendered
3821 It is a positive value, due to the grid's orientation with the Y axis
3824 @item max_glyph_d, descent
3825 the maximum distance from the baseline to the lowest grid coordinate
3826 used to place a glyph outline point, for all the rendered glyphs.
3827 This is a negative value, due to the grid's orientation, with the Y axis
3831 maximum glyph height, that is the maximum height for all the glyphs
3832 contained in the rendered text, it is equivalent to @var{ascent} -
3836 maximum glyph width, that is the maximum width for all the glyphs
3837 contained in the rendered text
3840 the number of input frame, starting from 0
3842 @item rand(min, max)
3843 return a random number included between @var{min} and @var{max}
3846 The input sample aspect ratio.
3849 timestamp expressed in seconds, NAN if the input timestamp is unknown
3852 the height of the rendered text
3855 the width of the rendered text
3859 the x and y offset coordinates where the text is drawn.
3861 These parameters allow the @var{x} and @var{y} expressions to refer
3862 each other, so you can for example specify @code{y=x/dar}.
3865 @anchor{drawtext_expansion}
3866 @subsection Text expansion
3868 If @option{expansion} is set to @code{strftime},
3869 the filter recognizes strftime() sequences in the provided text and
3870 expands them accordingly. Check the documentation of strftime(). This
3871 feature is deprecated.
3873 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3875 If @option{expansion} is set to @code{normal} (which is the default),
3876 the following expansion mechanism is used.
3878 The backslash character '\', followed by any character, always expands to
3879 the second character.
3881 Sequence of the form @code{%@{...@}} are expanded. The text between the
3882 braces is a function name, possibly followed by arguments separated by ':'.
3883 If the arguments contain special characters or delimiters (':' or '@}'),
3884 they should be escaped.
3886 Note that they probably must also be escaped as the value for the
3887 @option{text} option in the filter argument string and as the filter
3888 argument in the filtergraph description, and possibly also for the shell,
3889 that makes up to four levels of escaping; using a text file avoids these
3892 The following functions are available:
3897 The expression evaluation result.
3899 It must take one argument specifying the expression to be evaluated,
3900 which accepts the same constants and functions as the @var{x} and
3901 @var{y} values. Note that not all constants should be used, for
3902 example the text size is not known when evaluating the expression, so
3903 the constants @var{text_w} and @var{text_h} will have an undefined
3907 The time at which the filter is running, expressed in UTC.
3908 It can accept an argument: a strftime() format string.
3911 The time at which the filter is running, expressed in the local time zone.
3912 It can accept an argument: a strftime() format string.
3915 Frame metadata. It must take one argument specifying metadata key.
3918 The frame number, starting from 0.
3921 A 1 character description of the current picture type.
3924 The timestamp of the current frame.
3925 It can take up to two arguments.
3927 The first argument is the format of the timestamp; it defaults to @code{flt}
3928 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
3929 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
3931 The second argument is an offset added to the timestamp.
3935 @subsection Examples
3939 Draw "Test Text" with font FreeSerif, using the default values for the
3940 optional parameters.
3943 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
3947 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
3948 and y=50 (counting from the top-left corner of the screen), text is
3949 yellow with a red box around it. Both the text and the box have an
3953 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
3954 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
3957 Note that the double quotes are not necessary if spaces are not used
3958 within the parameter list.
3961 Show the text at the center of the video frame:
3963 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
3967 Show a text line sliding from right to left in the last row of the video
3968 frame. The file @file{LONG_LINE} is assumed to contain a single line
3971 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
3975 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
3977 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
3981 Draw a single green letter "g", at the center of the input video.
3982 The glyph baseline is placed at half screen height.
3984 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
3988 Show text for 1 second every 3 seconds:
3990 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
3994 Use fontconfig to set the font. Note that the colons need to be escaped.
3996 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
4000 Print the date of a real-time encoding (see strftime(3)):
4002 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
4007 For more information about libfreetype, check:
4008 @url{http://www.freetype.org/}.
4010 For more information about fontconfig, check:
4011 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
4015 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
4017 The filter accepts the following options:
4022 Set low and high threshold values used by the Canny thresholding
4025 The high threshold selects the "strong" edge pixels, which are then
4026 connected through 8-connectivity with the "weak" edge pixels selected
4027 by the low threshold.
4029 @var{low} and @var{high} threshold values must be chosen in the range
4030 [0,1], and @var{low} should be lesser or equal to @var{high}.
4032 Default value for @var{low} is @code{20/255}, and default value for @var{high}
4036 Define the drawing mode.
4040 Draw white/gray wires on black background.
4043 Mix the colors to create a paint/cartoon effect.
4046 Default value is @var{wires}.
4049 @subsection Examples
4053 Standard edge detection with custom values for the hysteresis thresholding:
4055 edgedetect=low=0.1:high=0.4
4059 Painting effect without thresholding:
4061 edgedetect=mode=colormix:high=0
4065 @section extractplanes
4067 Extract color channel components from input video stream into
4068 separate grayscale video streams.
4070 The filter accepts the following option:
4074 Set plane(s) to extract.
4076 Available values for planes are:
4087 Choosing planes not available in the input will result in an error.
4088 That means you cannot select @code{r}, @code{g}, @code{b} planes
4089 with @code{y}, @code{u}, @code{v} planes at same time.
4092 @subsection Examples
4096 Extract luma, u and v color channel component from input video frame
4097 into 3 grayscale outputs:
4099 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
4105 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4107 For each input image, the filter will compute the optimal mapping from
4108 the input to the output given the codebook length, that is the number
4109 of distinct output colors.
4111 This filter accepts the following options.
4114 @item codebook_length, l
4115 Set codebook length. The value must be a positive integer, and
4116 represents the number of distinct output colors. Default value is 256.
4119 Set the maximum number of iterations to apply for computing the optimal
4120 mapping. The higher the value the better the result and the higher the
4121 computation time. Default value is 1.
4124 Set a random seed, must be an integer included between 0 and
4125 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4126 will try to use a good random seed on a best effort basis.
4131 Apply a fade-in/out effect to the input video.
4133 It accepts the following parameters:
4137 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4139 Default is @code{in}.
4141 @item start_frame, s
4142 Specify the number of the frame to start applying the fade
4143 effect at. Default is 0.
4146 The number of frames that the fade effect lasts. At the end of the
4147 fade-in effect, the output video will have the same intensity as the input video.
4148 At the end of the fade-out transition, the output video will be filled with the
4149 selected @option{color}.
4153 If set to 1, fade only alpha channel, if one exists on the input.
4156 @item start_time, st
4157 Specify the timestamp (in seconds) of the frame to start to apply the fade
4158 effect. If both start_frame and start_time are specified, the fade will start at
4159 whichever comes last. Default is 0.
4162 The number of seconds for which the fade effect has to last. At the end of the
4163 fade-in effect the output video will have the same intensity as the input video,
4164 at the end of the fade-out transition the output video will be filled with the
4165 selected @option{color}.
4166 If both duration and nb_frames are specified, duration is used. Default is 0.
4169 Specify the color of the fade. Default is "black".
4172 @subsection Examples
4176 Fade in the first 30 frames of video:
4181 The command above is equivalent to:
4187 Fade out the last 45 frames of a 200-frame video:
4190 fade=type=out:start_frame=155:nb_frames=45
4194 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4196 fade=in:0:25, fade=out:975:25
4200 Make the first 5 frames yellow, then fade in from frame 5-24:
4202 fade=in:5:20:color=yellow
4206 Fade in alpha over first 25 frames of video:
4208 fade=in:0:25:alpha=1
4212 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4214 fade=t=in:st=5.5:d=0.5
4221 Extract a single field from an interlaced image using stride
4222 arithmetic to avoid wasting CPU time. The output frames are marked as
4225 The filter accepts the following options:
4229 Specify whether to extract the top (if the value is @code{0} or
4230 @code{top}) or the bottom field (if the value is @code{1} or
4236 Field matching filter for inverse telecine. It is meant to reconstruct the
4237 progressive frames from a telecined stream. The filter does not drop duplicated
4238 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4239 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4241 The separation of the field matching and the decimation is notably motivated by
4242 the possibility of inserting a de-interlacing filter fallback between the two.
4243 If the source has mixed telecined and real interlaced content,
4244 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4245 But these remaining combed frames will be marked as interlaced, and thus can be
4246 de-interlaced by a later filter such as @ref{yadif} before decimation.
4248 In addition to the various configuration options, @code{fieldmatch} can take an
4249 optional second stream, activated through the @option{ppsrc} option. If
4250 enabled, the frames reconstruction will be based on the fields and frames from
4251 this second stream. This allows the first input to be pre-processed in order to
4252 help the various algorithms of the filter, while keeping the output lossless
4253 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4254 or brightness/contrast adjustments can help.
4256 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4257 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4258 which @code{fieldmatch} is based on. While the semantic and usage are very
4259 close, some behaviour and options names can differ.
4261 The filter accepts the following options:
4265 Specify the assumed field order of the input stream. Available values are:
4269 Auto detect parity (use FFmpeg's internal parity value).
4271 Assume bottom field first.
4273 Assume top field first.
4276 Note that it is sometimes recommended not to trust the parity announced by the
4279 Default value is @var{auto}.
4282 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4283 sense that it won't risk creating jerkiness due to duplicate frames when
4284 possible, but if there are bad edits or blended fields it will end up
4285 outputting combed frames when a good match might actually exist. On the other
4286 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4287 but will almost always find a good frame if there is one. The other values are
4288 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4289 jerkiness and creating duplicate frames versus finding good matches in sections
4290 with bad edits, orphaned fields, blended fields, etc.
4292 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4294 Available values are:
4298 2-way matching (p/c)
4300 2-way matching, and trying 3rd match if still combed (p/c + n)
4302 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4304 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4305 still combed (p/c + n + u/b)
4307 3-way matching (p/c/n)
4309 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4310 detected as combed (p/c/n + u/b)
4313 The parenthesis at the end indicate the matches that would be used for that
4314 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4317 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4320 Default value is @var{pc_n}.
4323 Mark the main input stream as a pre-processed input, and enable the secondary
4324 input stream as the clean source to pick the fields from. See the filter
4325 introduction for more details. It is similar to the @option{clip2} feature from
4328 Default value is @code{0} (disabled).
4331 Set the field to match from. It is recommended to set this to the same value as
4332 @option{order} unless you experience matching failures with that setting. In
4333 certain circumstances changing the field that is used to match from can have a
4334 large impact on matching performance. Available values are:
4338 Automatic (same value as @option{order}).
4340 Match from the bottom field.
4342 Match from the top field.
4345 Default value is @var{auto}.
4348 Set whether or not chroma is included during the match comparisons. In most
4349 cases it is recommended to leave this enabled. You should set this to @code{0}
4350 only if your clip has bad chroma problems such as heavy rainbowing or other
4351 artifacts. Setting this to @code{0} could also be used to speed things up at
4352 the cost of some accuracy.
4354 Default value is @code{1}.
4358 These define an exclusion band which excludes the lines between @option{y0} and
4359 @option{y1} from being included in the field matching decision. An exclusion
4360 band can be used to ignore subtitles, a logo, or other things that may
4361 interfere with the matching. @option{y0} sets the starting scan line and
4362 @option{y1} sets the ending line; all lines in between @option{y0} and
4363 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4364 @option{y0} and @option{y1} to the same value will disable the feature.
4365 @option{y0} and @option{y1} defaults to @code{0}.
4368 Set the scene change detection threshold as a percentage of maximum change on
4369 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4370 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4371 @option{scthresh} is @code{[0.0, 100.0]}.
4373 Default value is @code{12.0}.
4376 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4377 account the combed scores of matches when deciding what match to use as the
4378 final match. Available values are:
4382 No final matching based on combed scores.
4384 Combed scores are only used when a scene change is detected.
4386 Use combed scores all the time.
4389 Default is @var{sc}.
4392 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4393 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4394 Available values are:
4398 No forced calculation.
4400 Force p/c/n calculations.
4402 Force p/c/n/u/b calculations.
4405 Default value is @var{none}.
4408 This is the area combing threshold used for combed frame detection. This
4409 essentially controls how "strong" or "visible" combing must be to be detected.
4410 Larger values mean combing must be more visible and smaller values mean combing
4411 can be less visible or strong and still be detected. Valid settings are from
4412 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4413 be detected as combed). This is basically a pixel difference value. A good
4414 range is @code{[8, 12]}.
4416 Default value is @code{9}.
4419 Sets whether or not chroma is considered in the combed frame decision. Only
4420 disable this if your source has chroma problems (rainbowing, etc.) that are
4421 causing problems for the combed frame detection with chroma enabled. Actually,
4422 using @option{chroma}=@var{0} is usually more reliable, except for the case
4423 where there is chroma only combing in the source.
4425 Default value is @code{0}.
4429 Respectively set the x-axis and y-axis size of the window used during combed
4430 frame detection. This has to do with the size of the area in which
4431 @option{combpel} pixels are required to be detected as combed for a frame to be
4432 declared combed. See the @option{combpel} parameter description for more info.
4433 Possible values are any number that is a power of 2 starting at 4 and going up
4436 Default value is @code{16}.
4439 The number of combed pixels inside any of the @option{blocky} by
4440 @option{blockx} size blocks on the frame for the frame to be detected as
4441 combed. While @option{cthresh} controls how "visible" the combing must be, this
4442 setting controls "how much" combing there must be in any localized area (a
4443 window defined by the @option{blockx} and @option{blocky} settings) on the
4444 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4445 which point no frames will ever be detected as combed). This setting is known
4446 as @option{MI} in TFM/VFM vocabulary.
4448 Default value is @code{80}.
4451 @anchor{p/c/n/u/b meaning}
4452 @subsection p/c/n/u/b meaning
4454 @subsubsection p/c/n
4456 We assume the following telecined stream:
4459 Top fields: 1 2 2 3 4
4460 Bottom fields: 1 2 3 4 4
4463 The numbers correspond to the progressive frame the fields relate to. Here, the
4464 first two frames are progressive, the 3rd and 4th are combed, and so on.
4466 When @code{fieldmatch} is configured to run a matching from bottom
4467 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4472 B 1 2 3 4 4 <-- matching reference
4481 As a result of the field matching, we can see that some frames get duplicated.
4482 To perform a complete inverse telecine, you need to rely on a decimation filter
4483 after this operation. See for instance the @ref{decimate} filter.
4485 The same operation now matching from top fields (@option{field}=@var{top})
4490 T 1 2 2 3 4 <-- matching reference
4500 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4501 basically, they refer to the frame and field of the opposite parity:
4504 @item @var{p} matches the field of the opposite parity in the previous frame
4505 @item @var{c} matches the field of the opposite parity in the current frame
4506 @item @var{n} matches the field of the opposite parity in the next frame
4511 The @var{u} and @var{b} matching are a bit special in the sense that they match
4512 from the opposite parity flag. In the following examples, we assume that we are
4513 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4514 'x' is placed above and below each matched fields.
4516 With bottom matching (@option{field}=@var{bottom}):
4521 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4522 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4530 With top matching (@option{field}=@var{top}):
4535 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4536 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4544 @subsection Examples
4546 Simple IVTC of a top field first telecined stream:
4548 fieldmatch=order=tff:combmatch=none, decimate
4551 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4553 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4558 Transform the field order of the input video.
4560 It accepts the following parameters:
4565 The output field order. Valid values are @var{tff} for top field first or @var{bff}
4566 for bottom field first.
4569 The default value is @samp{tff}.
4571 The transformation is done by shifting the picture content up or down
4572 by one line, and filling the remaining line with appropriate picture content.
4573 This method is consistent with most broadcast field order converters.
4575 If the input video is not flagged as being interlaced, or it is already
4576 flagged as being of the required output field order, then this filter does
4577 not alter the incoming video.
4579 It is very useful when converting to or from PAL DV material,
4580 which is bottom field first.
4584 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4589 Buffer input images and send them when they are requested.
4591 It is mainly useful when auto-inserted by the libavfilter
4594 It does not take parameters.
4599 Convert the input video to one of the specified pixel formats.
4600 Libavfilter will try to pick one that is suitable as input to
4603 It accepts the following parameters:
4607 A '|'-separated list of pixel format names, such as
4608 "pix_fmts=yuv420p|monow|rgb24".
4612 @subsection Examples
4616 Convert the input video to the @var{yuv420p} format
4618 format=pix_fmts=yuv420p
4621 Convert the input video to any of the formats in the list
4623 format=pix_fmts=yuv420p|yuv444p|yuv410p
4630 Convert the video to specified constant frame rate by duplicating or dropping
4631 frames as necessary.
4633 It accepts the following parameters:
4637 The desired output frame rate. The default is @code{25}.
4642 Possible values are:
4645 zero round towards 0
4649 round towards -infinity
4651 round towards +infinity
4655 The default is @code{near}.
4658 Assume the first PTS should be the given value, in seconds. This allows for
4659 padding/trimming at the start of stream. By default, no assumption is made
4660 about the first frame's expected PTS, so no padding or trimming is done.
4661 For example, this could be set to 0 to pad the beginning with duplicates of
4662 the first frame if a video stream starts after the audio stream or to trim any
4663 frames with a negative PTS.
4667 Alternatively, the options can be specified as a flat string:
4668 @var{fps}[:@var{round}].
4670 See also the @ref{setpts} filter.
4672 @subsection Examples
4676 A typical usage in order to set the fps to 25:
4682 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4684 fps=fps=film:round=near
4690 Pack two different video streams into a stereoscopic video, setting proper
4691 metadata on supported codecs. The two views should have the same size and
4692 framerate and processing will stop when the shorter video ends. Please note
4693 that you may conveniently adjust view properties with the @ref{scale} and
4696 It accepts the following parameters:
4700 The desired packing format. Supported values are:
4705 The views are next to each other (default).
4708 The views are on top of each other.
4711 The views are packed by line.
4714 The views are packed by column.
4717 The views are temporally interleaved.
4726 # Convert left and right views into a frame-sequential video
4727 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
4729 # Convert views into a side-by-side video with the same output resolution as the input
4730 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
4735 Select one frame every N-th frame.
4737 This filter accepts the following option:
4740 Select frame after every @code{step} frames.
4741 Allowed values are positive integers higher than 0. Default value is @code{1}.
4747 Apply a frei0r effect to the input video.
4749 To enable the compilation of this filter, you need to install the frei0r
4750 header and configure FFmpeg with @code{--enable-frei0r}.
4752 It accepts the following parameters:
4757 The name of the frei0r effect to load. If the environment variable
4758 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
4759 directories specified by the colon-separated list in @env{FREIOR_PATH}.
4760 Otherwise, the standard frei0r paths are searched, in this order:
4761 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
4762 @file{/usr/lib/frei0r-1/}.
4765 A '|'-separated list of parameters to pass to the frei0r effect.
4769 A frei0r effect parameter can be a boolean (its value is either
4770 "y" or "n"), a double, a color (specified as
4771 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
4772 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
4773 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
4774 @var{X} and @var{Y} are floating point numbers) and/or a string.
4776 The number and types of parameters depend on the loaded effect. If an
4777 effect parameter is not specified, the default value is set.
4779 @subsection Examples
4783 Apply the distort0r effect, setting the first two double parameters:
4785 frei0r=filter_name=distort0r:filter_params=0.5|0.01
4789 Apply the colordistance effect, taking a color as the first parameter:
4791 frei0r=colordistance:0.2/0.3/0.4
4792 frei0r=colordistance:violet
4793 frei0r=colordistance:0x112233
4797 Apply the perspective effect, specifying the top left and top right image
4800 frei0r=perspective:0.2/0.2|0.8/0.2
4804 For more information, see
4805 @url{http://frei0r.dyne.org}
4809 The filter accepts the following options:
4813 Set the luminance expression.
4815 Set the chrominance blue expression.
4817 Set the chrominance red expression.
4819 Set the alpha expression.
4821 Set the red expression.
4823 Set the green expression.
4825 Set the blue expression.
4828 The colorspace is selected according to the specified options. If one
4829 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4830 options is specified, the filter will automatically select a YCbCr
4831 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4832 @option{blue_expr} options is specified, it will select an RGB
4835 If one of the chrominance expression is not defined, it falls back on the other
4836 one. If no alpha expression is specified it will evaluate to opaque value.
4837 If none of chrominance expressions are specified, they will evaluate
4838 to the luminance expression.
4840 The expressions can use the following variables and functions:
4844 The sequential number of the filtered frame, starting from @code{0}.
4848 The coordinates of the current sample.
4852 The width and height of the image.
4856 Width and height scale depending on the currently filtered plane. It is the
4857 ratio between the corresponding luma plane number of pixels and the current
4858 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4859 @code{0.5,0.5} for chroma planes.
4862 Time of the current frame, expressed in seconds.
4865 Return the value of the pixel at location (@var{x},@var{y}) of the current
4869 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
4873 Return the value of the pixel at location (@var{x},@var{y}) of the
4874 blue-difference chroma plane. Return 0 if there is no such plane.
4877 Return the value of the pixel at location (@var{x},@var{y}) of the
4878 red-difference chroma plane. Return 0 if there is no such plane.
4883 Return the value of the pixel at location (@var{x},@var{y}) of the
4884 red/green/blue component. Return 0 if there is no such component.
4887 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
4888 plane. Return 0 if there is no such plane.
4891 For functions, if @var{x} and @var{y} are outside the area, the value will be
4892 automatically clipped to the closer edge.
4894 @subsection Examples
4898 Flip the image horizontally:
4904 Generate a bidimensional sine wave, with angle @code{PI/3} and a
4905 wavelength of 100 pixels:
4907 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
4911 Generate a fancy enigmatic moving light:
4913 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
4917 Generate a quick emboss effect:
4919 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
4923 Modify RGB components depending on pixel position:
4925 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
4931 Fix the banding artifacts that are sometimes introduced into nearly flat
4932 regions by truncation to 8bit color depth.
4933 Interpolate the gradients that should go where the bands are, and
4936 It is designed for playback only. Do not use it prior to
4937 lossy compression, because compression tends to lose the dither and
4938 bring back the bands.
4940 It accepts the following parameters:
4945 The maximum amount by which the filter will change any one pixel. This is also
4946 the threshold for detecting nearly flat regions. Acceptable values range from
4947 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
4951 The neighborhood to fit the gradient to. A larger radius makes for smoother
4952 gradients, but also prevents the filter from modifying the pixels near detailed
4953 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
4954 values will be clipped to the valid range.
4958 Alternatively, the options can be specified as a flat string:
4959 @var{strength}[:@var{radius}]
4961 @subsection Examples
4965 Apply the filter with a @code{3.5} strength and radius of @code{8}:
4971 Specify radius, omitting the strength (which will fall-back to the default
4982 Apply a Hald CLUT to a video stream.
4984 First input is the video stream to process, and second one is the Hald CLUT.
4985 The Hald CLUT input can be a simple picture or a complete video stream.
4987 The filter accepts the following options:
4991 Force termination when the shortest input terminates. Default is @code{0}.
4993 Continue applying the last CLUT after the end of the stream. A value of
4994 @code{0} disable the filter after the last frame of the CLUT is reached.
4995 Default is @code{1}.
4998 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
4999 filters share the same internals).
5001 More information about the Hald CLUT can be found on Eskil Steenberg's website
5002 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
5004 @subsection Workflow examples
5006 @subsubsection Hald CLUT video stream
5008 Generate an identity Hald CLUT stream altered with various effects:
5010 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
5013 Note: make sure you use a lossless codec.
5015 Then use it with @code{haldclut} to apply it on some random stream:
5017 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
5020 The Hald CLUT will be applied to the 10 first seconds (duration of
5021 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
5022 to the remaining frames of the @code{mandelbrot} stream.
5024 @subsubsection Hald CLUT with preview
5026 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
5027 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
5028 biggest possible square starting at the top left of the picture. The remaining
5029 padding pixels (bottom or right) will be ignored. This area can be used to add
5030 a preview of the Hald CLUT.
5032 Typically, the following generated Hald CLUT will be supported by the
5033 @code{haldclut} filter:
5036 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
5037 pad=iw+320 [padded_clut];
5038 smptebars=s=320x256, split [a][b];
5039 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
5040 [main][b] overlay=W-320" -frames:v 1 clut.png
5043 It contains the original and a preview of the effect of the CLUT: SMPTE color
5044 bars are displayed on the right-top, and below the same color bars processed by
5047 Then, the effect of this Hald CLUT can be visualized with:
5049 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
5054 Flip the input video horizontally.
5056 For example, to horizontally flip the input video with @command{ffmpeg}:
5058 ffmpeg -i in.avi -vf "hflip" out.avi
5062 This filter applies a global color histogram equalization on a
5065 It can be used to correct video that has a compressed range of pixel
5066 intensities. The filter redistributes the pixel intensities to
5067 equalize their distribution across the intensity range. It may be
5068 viewed as an "automatically adjusting contrast filter". This filter is
5069 useful only for correcting degraded or poorly captured source
5072 The filter accepts the following options:
5076 Determine the amount of equalization to be applied. As the strength
5077 is reduced, the distribution of pixel intensities more-and-more
5078 approaches that of the input frame. The value must be a float number
5079 in the range [0,1] and defaults to 0.200.
5082 Set the maximum intensity that can generated and scale the output
5083 values appropriately. The strength should be set as desired and then
5084 the intensity can be limited if needed to avoid washing-out. The value
5085 must be a float number in the range [0,1] and defaults to 0.210.
5088 Set the antibanding level. If enabled the filter will randomly vary
5089 the luminance of output pixels by a small amount to avoid banding of
5090 the histogram. Possible values are @code{none}, @code{weak} or
5091 @code{strong}. It defaults to @code{none}.
5096 Compute and draw a color distribution histogram for the input video.
5098 The computed histogram is a representation of the color component
5099 distribution in an image.
5101 The filter accepts the following options:
5107 It accepts the following values:
5110 Standard histogram that displays the color components distribution in an
5111 image. Displays color graph for each color component. Shows distribution of
5112 the Y, U, V, A or R, G, B components, depending on input format, in the
5113 current frame. Below each graph a color component scale meter is shown.
5116 Displays chroma values (U/V color placement) in a two dimensional
5117 graph (which is called a vectorscope). The brighter a pixel in the
5118 vectorscope, the more pixels of the input frame correspond to that pixel
5119 (i.e., more pixels have this chroma value). The V component is displayed on
5120 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5121 side being V = 255. The U component is displayed on the vertical (Y) axis,
5122 with the top representing U = 0 and the bottom representing U = 255.
5124 The position of a white pixel in the graph corresponds to the chroma value of
5125 a pixel of the input clip. The graph can therefore be used to read the hue
5126 (color flavor) and the saturation (the dominance of the hue in the color). As
5127 the hue of a color changes, it moves around the square. At the center of the
5128 square the saturation is zero, which means that the corresponding pixel has no
5129 color. If the amount of a specific color is increased (while leaving the other
5130 colors unchanged) the saturation increases, and the indicator moves towards
5131 the edge of the square.
5134 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5138 Per row/column color component graph. In row mode, the graph on the left side
5139 represents color component value 0 and the right side represents value = 255.
5140 In column mode, the top side represents color component value = 0 and bottom
5141 side represents value = 255.
5143 Default value is @code{levels}.
5146 Set height of level in @code{levels}. Default value is @code{200}.
5147 Allowed range is [50, 2048].
5150 Set height of color scale in @code{levels}. Default value is @code{12}.
5151 Allowed range is [0, 40].
5154 Set step for @code{waveform} mode. Smaller values are useful to find out how
5155 many values of the same luminance are distributed across input rows/columns.
5156 Default value is @code{10}. Allowed range is [1, 255].
5159 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5160 Default is @code{row}.
5162 @item waveform_mirror
5163 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5164 means mirrored. In mirrored mode, higher values will be represented on the left
5165 side for @code{row} mode and at the top for @code{column} mode. Default is
5166 @code{0} (unmirrored).
5169 Set display mode for @code{waveform} and @code{levels}.
5170 It accepts the following values:
5173 Display separate graph for the color components side by side in
5174 @code{row} waveform mode or one below the other in @code{column} waveform mode
5175 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5176 per color component graphs are placed below each other.
5178 Using this display mode in @code{waveform} histogram mode makes it easy to
5179 spot color casts in the highlights and shadows of an image, by comparing the
5180 contours of the top and the bottom graphs of each waveform. Since whites,
5181 grays, and blacks are characterized by exactly equal amounts of red, green,
5182 and blue, neutral areas of the picture should display three waveforms of
5183 roughly equal width/height. If not, the correction is easy to perform by
5184 making level adjustments the three waveforms.
5187 Presents information identical to that in the @code{parade}, except
5188 that the graphs representing color components are superimposed directly
5191 This display mode in @code{waveform} histogram mode makes it easier to spot
5192 relative differences or similarities in overlapping areas of the color
5193 components that are supposed to be identical, such as neutral whites, grays,
5196 Default is @code{parade}.
5199 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5200 Default is @code{linear}.
5203 @subsection Examples
5208 Calculate and draw histogram:
5210 ffplay -i input -vf histogram
5218 This is a high precision/quality 3d denoise filter. It aims to reduce
5219 image noise, producing smooth images and making still images really
5220 still. It should enhance compressibility.
5222 It accepts the following optional parameters:
5226 A non-negative floating point number which specifies spatial luma strength.
5229 @item chroma_spatial
5230 A non-negative floating point number which specifies spatial chroma strength.
5231 It defaults to 3.0*@var{luma_spatial}/4.0.
5234 A floating point number which specifies luma temporal strength. It defaults to
5235 6.0*@var{luma_spatial}/4.0.
5238 A floating point number which specifies chroma temporal strength. It defaults to
5239 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5244 Apply a high-quality magnification filter designed for pixel art. This filter
5245 was originally created by Maxim Stepin.
5247 It accepts the following option:
5251 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
5252 @code{hq3x} and @code{4} for @code{hq4x}.
5253 Default is @code{3}.
5258 Modify the hue and/or the saturation of the input.
5260 It accepts the following parameters:
5264 Specify the hue angle as a number of degrees. It accepts an expression,
5265 and defaults to "0".
5268 Specify the saturation in the [-10,10] range. It accepts an expression and
5272 Specify the hue angle as a number of radians. It accepts an
5273 expression, and defaults to "0".
5276 Specify the brightness in the [-10,10] range. It accepts an expression and
5280 @option{h} and @option{H} are mutually exclusive, and can't be
5281 specified at the same time.
5283 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5284 expressions containing the following constants:
5288 frame count of the input frame starting from 0
5291 presentation timestamp of the input frame expressed in time base units
5294 frame rate of the input video, NAN if the input frame rate is unknown
5297 timestamp expressed in seconds, NAN if the input timestamp is unknown
5300 time base of the input video
5303 @subsection Examples
5307 Set the hue to 90 degrees and the saturation to 1.0:
5313 Same command but expressing the hue in radians:
5319 Rotate hue and make the saturation swing between 0
5320 and 2 over a period of 1 second:
5322 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5326 Apply a 3 seconds saturation fade-in effect starting at 0:
5331 The general fade-in expression can be written as:
5333 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5337 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5339 hue="s=max(0\, min(1\, (8-t)/3))"
5342 The general fade-out expression can be written as:
5344 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5349 @subsection Commands
5351 This filter supports the following commands:
5357 Modify the hue and/or the saturation and/or brightness of the input video.
5358 The command accepts the same syntax of the corresponding option.
5360 If the specified expression is not valid, it is kept at its current
5366 Detect video interlacing type.
5368 This filter tries to detect if the input is interlaced or progressive,
5369 top or bottom field first.
5371 The filter accepts the following options:
5375 Set interlacing threshold.
5377 Set progressive threshold.
5382 Deinterleave or interleave fields.
5384 This filter allows one to process interlaced images fields without
5385 deinterlacing them. Deinterleaving splits the input frame into 2
5386 fields (so called half pictures). Odd lines are moved to the top
5387 half of the output image, even lines to the bottom half.
5388 You can process (filter) them independently and then re-interleave them.
5390 The filter accepts the following options:
5394 @item chroma_mode, c
5396 Available values for @var{luma_mode}, @var{chroma_mode} and
5397 @var{alpha_mode} are:
5403 @item deinterleave, d
5404 Deinterleave fields, placing one above the other.
5407 Interleave fields. Reverse the effect of deinterleaving.
5409 Default value is @code{none}.
5412 @item chroma_swap, cs
5413 @item alpha_swap, as
5414 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5419 Simple interlacing filter from progressive contents. This interleaves upper (or
5420 lower) lines from odd frames with lower (or upper) lines from even frames,
5421 halving the frame rate and preserving image height. A vertical lowpass filter
5422 is always applied in order to avoid twitter effects and reduce moiré patterns.
5425 Original Original New Frame
5426 Frame 'j' Frame 'j+1' (tff)
5427 ========== =========== ==================
5428 Line 0 --------------------> Frame 'j' Line 0
5429 Line 1 Line 1 ----> Frame 'j+1' Line 1
5430 Line 2 ---------------------> Frame 'j' Line 2
5431 Line 3 Line 3 ----> Frame 'j+1' Line 3
5433 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5436 It accepts the following optional parameters:
5440 This determines whether the interlaced frame is taken from the even
5441 (tff - default) or odd (bff) lines of the progressive frame.
5446 Deinterlace input video by applying Donald Graft's adaptive kernel
5447 deinterling. Work on interlaced parts of a video to produce
5450 The description of the accepted parameters follows.
5454 Set the threshold which affects the filter's tolerance when
5455 determining if a pixel line must be processed. It must be an integer
5456 in the range [0,255] and defaults to 10. A value of 0 will result in
5457 applying the process on every pixels.
5460 Paint pixels exceeding the threshold value to white if set to 1.
5464 Set the fields order. Swap fields if set to 1, leave fields alone if
5468 Enable additional sharpening if set to 1. Default is 0.
5471 Enable twoway sharpening if set to 1. Default is 0.
5474 @subsection Examples
5478 Apply default values:
5480 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5484 Enable additional sharpening:
5490 Paint processed pixels in white:
5499 Apply a 3D LUT to an input video.
5501 The filter accepts the following options:
5505 Set the 3D LUT file name.
5507 Currently supported formats:
5519 Select interpolation mode.
5521 Available values are:
5525 Use values from the nearest defined point.
5527 Interpolate values using the 8 points defining a cube.
5529 Interpolate values using a tetrahedron.
5533 @section lut, lutrgb, lutyuv
5535 Compute a look-up table for binding each pixel component input value
5536 to an output value, and apply it to the input video.
5538 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5539 to an RGB input video.
5541 These filters accept the following parameters:
5544 set first pixel component expression
5546 set second pixel component expression
5548 set third pixel component expression
5550 set fourth pixel component expression, corresponds to the alpha component
5553 set red component expression
5555 set green component expression
5557 set blue component expression
5559 alpha component expression
5562 set Y/luminance component expression
5564 set U/Cb component expression
5566 set V/Cr component expression
5569 Each of them specifies the expression to use for computing the lookup table for
5570 the corresponding pixel component values.
5572 The exact component associated to each of the @var{c*} options depends on the
5575 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5576 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5578 The expressions can contain the following constants and functions:
5583 The input width and height.
5586 The input value for the pixel component.
5589 The input value, clipped to the @var{minval}-@var{maxval} range.
5592 The maximum value for the pixel component.
5595 The minimum value for the pixel component.
5598 The negated value for the pixel component value, clipped to the
5599 @var{minval}-@var{maxval} range; it corresponds to the expression
5600 "maxval-clipval+minval".
5603 The computed value in @var{val}, clipped to the
5604 @var{minval}-@var{maxval} range.
5606 @item gammaval(gamma)
5607 The computed gamma correction value of the pixel component value,
5608 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
5610 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
5614 All expressions default to "val".
5616 @subsection Examples
5622 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
5623 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
5626 The above is the same as:
5628 lutrgb="r=negval:g=negval:b=negval"
5629 lutyuv="y=negval:u=negval:v=negval"
5639 Remove chroma components, turning the video into a graytone image:
5641 lutyuv="u=128:v=128"
5645 Apply a luma burning effect:
5651 Remove green and blue components:
5657 Set a constant alpha channel value on input:
5659 format=rgba,lutrgb=a="maxval-minval/2"
5663 Correct luminance gamma by a factor of 0.5:
5665 lutyuv=y=gammaval(0.5)
5669 Discard least significant bits of luma:
5671 lutyuv=y='bitand(val, 128+64+32)'
5675 @section mergeplanes
5677 Merge color channel components from several video streams.
5679 The filter accepts up to 4 input streams, and merge selected input
5680 planes to the output video.
5682 This filter accepts the following options:
5685 Set input to output plane mapping. Default is @code{0}.
5687 The mappings is specified as a bitmap. It should be specified as a
5688 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
5689 mapping for the first plane of the output stream. 'A' sets the number of
5690 the input stream to use (from 0 to 3), and 'a' the plane number of the
5691 corresponding input to use (from 0 to 3). The rest of the mappings is
5692 similar, 'Bb' describes the mapping for the output stream second
5693 plane, 'Cc' describes the mapping for the output stream third plane and
5694 'Dd' describes the mapping for the output stream fourth plane.
5697 Set output pixel format. Default is @code{yuva444p}.
5700 @subsection Examples
5704 Merge three gray video streams of same width and height into single video stream:
5706 [a0][a1][a2]mergeplanes=0x001020:yuv444p
5710 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
5712 [a0][a1]mergeplanes=0x00010210:yuva444p
5716 Swap Y and A plane in yuva444p stream:
5718 format=yuva444p,mergeplanes=0x03010200:yuva444p
5722 Swap U and V plane in yuv420p stream:
5724 format=yuv420p,mergeplanes=0x000201:yuv420p
5728 Cast a rgb24 clip to yuv444p:
5730 format=rgb24,mergeplanes=0x000102:yuv444p
5736 Apply motion-compensation deinterlacing.
5738 It needs one field per frame as input and must thus be used together
5739 with yadif=1/3 or equivalent.
5741 This filter accepts the following options:
5744 Set the deinterlacing mode.
5746 It accepts one of the following values:
5751 use iterative motion estimation
5753 like @samp{slow}, but use multiple reference frames.
5755 Default value is @samp{fast}.
5758 Set the picture field parity assumed for the input video. It must be
5759 one of the following values:
5763 assume top field first
5765 assume bottom field first
5768 Default value is @samp{bff}.
5771 Set per-block quantization parameter (QP) used by the internal
5774 Higher values should result in a smoother motion vector field but less
5775 optimal individual vectors. Default value is 1.
5780 Apply an MPlayer filter to the input video.
5782 This filter provides a wrapper around some of the filters of
5785 This wrapper is considered experimental. Some of the wrapped filters
5786 may not work properly and we may drop support for them, as they will
5787 be implemented natively into FFmpeg. Thus you should avoid
5788 depending on them when writing portable scripts.
5790 The filter accepts the parameters:
5791 @var{filter_name}[:=]@var{filter_params}
5793 @var{filter_name} is the name of a supported MPlayer filter,
5794 @var{filter_params} is a string containing the parameters accepted by
5797 The list of the currently supported filters follows:
5808 The parameter syntax and behavior for the listed filters are the same
5809 of the corresponding MPlayer filters. For detailed instructions check
5810 the "VIDEO FILTERS" section in the MPlayer manual.
5812 @subsection Examples
5816 Adjust gamma, brightness, contrast:
5822 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
5826 Drop frames that do not differ greatly from the previous frame in
5827 order to reduce frame rate.
5829 The main use of this filter is for very-low-bitrate encoding
5830 (e.g. streaming over dialup modem), but it could in theory be used for
5831 fixing movies that were inverse-telecined incorrectly.
5833 A description of the accepted options follows.
5837 Set the maximum number of consecutive frames which can be dropped (if
5838 positive), or the minimum interval between dropped frames (if
5839 negative). If the value is 0, the frame is dropped unregarding the
5840 number of previous sequentially dropped frames.
5847 Set the dropping threshold values.
5849 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
5850 represent actual pixel value differences, so a threshold of 64
5851 corresponds to 1 unit of difference for each pixel, or the same spread
5852 out differently over the block.
5854 A frame is a candidate for dropping if no 8x8 blocks differ by more
5855 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
5856 meaning the whole image) differ by more than a threshold of @option{lo}.
5858 Default value for @option{hi} is 64*12, default value for @option{lo} is
5859 64*5, and default value for @option{frac} is 0.33.
5867 It accepts an integer in input; if non-zero it negates the
5868 alpha component (if available). The default value in input is 0.
5872 Force libavfilter not to use any of the specified pixel formats for the
5873 input to the next filter.
5875 It accepts the following parameters:
5879 A '|'-separated list of pixel format names, such as
5880 apix_fmts=yuv420p|monow|rgb24".
5884 @subsection Examples
5888 Force libavfilter to use a format different from @var{yuv420p} for the
5889 input to the vflip filter:
5891 noformat=pix_fmts=yuv420p,vflip
5895 Convert the input video to any of the formats not contained in the list:
5897 noformat=yuv420p|yuv444p|yuv410p
5903 Add noise on video input frame.
5905 The filter accepts the following options:
5913 Set noise seed for specific pixel component or all pixel components in case
5914 of @var{all_seed}. Default value is @code{123457}.
5916 @item all_strength, alls
5917 @item c0_strength, c0s
5918 @item c1_strength, c1s
5919 @item c2_strength, c2s
5920 @item c3_strength, c3s
5921 Set noise strength for specific pixel component or all pixel components in case
5922 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
5924 @item all_flags, allf
5929 Set pixel component flags or set flags for all components if @var{all_flags}.
5930 Available values for component flags are:
5933 averaged temporal noise (smoother)
5935 mix random noise with a (semi)regular pattern
5937 temporal noise (noise pattern changes between frames)
5939 uniform noise (gaussian otherwise)
5943 @subsection Examples
5945 Add temporal and uniform noise to input video:
5947 noise=alls=20:allf=t+u
5952 Pass the video source unchanged to the output.
5956 Apply a video transform using libopencv.
5958 To enable this filter, install the libopencv library and headers and
5959 configure FFmpeg with @code{--enable-libopencv}.
5961 It accepts the following parameters:
5966 The name of the libopencv filter to apply.
5969 The parameters to pass to the libopencv filter. If not specified, the default
5974 Refer to the official libopencv documentation for more precise
5976 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
5978 Several libopencv filters are supported; see the following subsections.
5983 Dilate an image by using a specific structuring element.
5984 It corresponds to the libopencv function @code{cvDilate}.
5986 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
5988 @var{struct_el} represents a structuring element, and has the syntax:
5989 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
5991 @var{cols} and @var{rows} represent the number of columns and rows of
5992 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
5993 point, and @var{shape} the shape for the structuring element. @var{shape}
5994 must be "rect", "cross", "ellipse", or "custom".
5996 If the value for @var{shape} is "custom", it must be followed by a
5997 string of the form "=@var{filename}". The file with name
5998 @var{filename} is assumed to represent a binary image, with each
5999 printable character corresponding to a bright pixel. When a custom
6000 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
6001 or columns and rows of the read file are assumed instead.
6003 The default value for @var{struct_el} is "3x3+0x0/rect".
6005 @var{nb_iterations} specifies the number of times the transform is
6006 applied to the image, and defaults to 1.
6010 # Use the default values
6013 # Dilate using a structuring element with a 5x5 cross, iterating two times
6014 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
6016 # Read the shape from the file diamond.shape, iterating two times.
6017 # The file diamond.shape may contain a pattern of characters like this
6023 # The specified columns and rows are ignored
6024 # but the anchor point coordinates are not
6025 ocv=dilate:0x0+2x2/custom=diamond.shape|2
6030 Erode an image by using a specific structuring element.
6031 It corresponds to the libopencv function @code{cvErode}.
6033 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
6034 with the same syntax and semantics as the @ref{dilate} filter.
6038 Smooth the input video.
6040 The filter takes the following parameters:
6041 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
6043 @var{type} is the type of smooth filter to apply, and must be one of
6044 the following values: "blur", "blur_no_scale", "median", "gaussian",
6045 or "bilateral". The default value is "gaussian".
6047 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
6048 depend on the smooth type. @var{param1} and
6049 @var{param2} accept integer positive values or 0. @var{param3} and
6050 @var{param4} accept floating point values.
6052 The default value for @var{param1} is 3. The default value for the
6053 other parameters is 0.
6055 These parameters correspond to the parameters assigned to the
6056 libopencv function @code{cvSmooth}.
6061 Overlay one video on top of another.
6063 It takes two inputs and has one output. The first input is the "main"
6064 video on which the second input is overlayed.
6066 It accepts the following parameters:
6068 A description of the accepted options follows.
6073 Set the expression for the x and y coordinates of the overlayed video
6074 on the main video. Default value is "0" for both expressions. In case
6075 the expression is invalid, it is set to a huge value (meaning that the
6076 overlay will not be displayed within the output visible area).
6079 The action to take when EOF is encountered on the secondary input; it accepts
6080 one of the following values:
6084 Repeat the last frame (the default).
6088 Pass the main input through.
6092 Set when the expressions for @option{x}, and @option{y} are evaluated.
6094 It accepts the following values:
6097 only evaluate expressions once during the filter initialization or
6098 when a command is processed
6101 evaluate expressions for each incoming frame
6104 Default value is @samp{frame}.
6107 If set to 1, force the output to terminate when the shortest input
6108 terminates. Default value is 0.
6111 Set the format for the output video.
6113 It accepts the following values:
6128 Default value is @samp{yuv420}.
6130 @item rgb @emph{(deprecated)}
6131 If set to 1, force the filter to accept inputs in the RGB
6132 color space. Default value is 0. This option is deprecated, use
6133 @option{format} instead.
6136 If set to 1, force the filter to draw the last overlay frame over the
6137 main input until the end of the stream. A value of 0 disables this
6138 behavior. Default value is 1.
6141 The @option{x}, and @option{y} expressions can contain the following
6147 The main input width and height.
6151 The overlay input width and height.
6155 The computed values for @var{x} and @var{y}. They are evaluated for
6160 horizontal and vertical chroma subsample values of the output
6161 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6165 the number of input frame, starting from 0
6168 the position in the file of the input frame, NAN if unknown
6171 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6175 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6176 when evaluation is done @emph{per frame}, and will evaluate to NAN
6177 when @option{eval} is set to @samp{init}.
6179 Be aware that frames are taken from each input video in timestamp
6180 order, hence, if their initial timestamps differ, it is a good idea
6181 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6182 have them begin in the same zero timestamp, as the example for
6183 the @var{movie} filter does.
6185 You can chain together more overlays but you should test the
6186 efficiency of such approach.
6188 @subsection Commands
6190 This filter supports the following commands:
6194 Modify the x and y of the overlay input.
6195 The command accepts the same syntax of the corresponding option.
6197 If the specified expression is not valid, it is kept at its current
6201 @subsection Examples
6205 Draw the overlay at 10 pixels from the bottom right corner of the main
6208 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6211 Using named options the example above becomes:
6213 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6217 Insert a transparent PNG logo in the bottom left corner of the input,
6218 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6220 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6224 Insert 2 different transparent PNG logos (second logo on bottom
6225 right corner) using the @command{ffmpeg} tool:
6227 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
6231 Add a transparent color layer on top of the main video; @code{WxH}
6232 must specify the size of the main input to the overlay filter:
6234 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6238 Play an original video and a filtered version (here with the deshake
6239 filter) side by side using the @command{ffplay} tool:
6241 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6244 The above command is the same as:
6246 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6250 Make a sliding overlay appearing from the left to the right top part of the
6251 screen starting since time 2:
6253 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6257 Compose output by putting two input videos side to side:
6259 ffmpeg -i left.avi -i right.avi -filter_complex "
6260 nullsrc=size=200x100 [background];
6261 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6262 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6263 [background][left] overlay=shortest=1 [background+left];
6264 [background+left][right] overlay=shortest=1:x=100 [left+right]
6269 Mask 10-20 seconds of a video by applying the delogo filter to a section
6271 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6272 -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]'
6277 Chain several overlays in cascade:
6279 nullsrc=s=200x200 [bg];
6280 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6281 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6282 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6283 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6284 [in3] null, [mid2] overlay=100:100 [out0]
6291 Apply Overcomplete Wavelet denoiser.
6293 The filter accepts the following options:
6299 Larger depth values will denoise lower frequency components more, but
6300 slow down filtering.
6302 Must be an int in the range 8-16, default is @code{8}.
6304 @item luma_strength, ls
6307 Must be a double value in the range 0-1000, default is @code{1.0}.
6309 @item chroma_strength, cs
6310 Set chroma strength.
6312 Must be a double value in the range 0-1000, default is @code{1.0}.
6317 Add paddings to the input image, and place the original input at the
6318 provided @var{x}, @var{y} coordinates.
6320 It accepts the following parameters:
6325 Specify an expression for the size of the output image with the
6326 paddings added. If the value for @var{width} or @var{height} is 0, the
6327 corresponding input size is used for the output.
6329 The @var{width} expression can reference the value set by the
6330 @var{height} expression, and vice versa.
6332 The default value of @var{width} and @var{height} is 0.
6336 Specify the offsets to place the input image at within the padded area,
6337 with respect to the top/left border of the output image.
6339 The @var{x} expression can reference the value set by the @var{y}
6340 expression, and vice versa.
6342 The default value of @var{x} and @var{y} is 0.
6345 Specify the color of the padded area. For the syntax of this option,
6346 check the "Color" section in the ffmpeg-utils manual.
6348 The default value of @var{color} is "black".
6351 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6352 options are expressions containing the following constants:
6357 The input video width and height.
6361 These are the same as @var{in_w} and @var{in_h}.
6365 The output width and height (the size of the padded area), as
6366 specified by the @var{width} and @var{height} expressions.
6370 These are the same as @var{out_w} and @var{out_h}.
6374 The x and y offsets as specified by the @var{x} and @var{y}
6375 expressions, or NAN if not yet specified.
6378 same as @var{iw} / @var{ih}
6381 input sample aspect ratio
6384 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6388 The horizontal and vertical chroma subsample values. For example for the
6389 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6392 @subsection Examples
6396 Add paddings with the color "violet" to the input video. The output video
6397 size is 640x480, and the top-left corner of the input video is placed at
6400 pad=640:480:0:40:violet
6403 The example above is equivalent to the following command:
6405 pad=width=640:height=480:x=0:y=40:color=violet
6409 Pad the input to get an output with dimensions increased by 3/2,
6410 and put the input video at the center of the padded area:
6412 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6416 Pad the input to get a squared output with size equal to the maximum
6417 value between the input width and height, and put the input video at
6418 the center of the padded area:
6420 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6424 Pad the input to get a final w/h ratio of 16:9:
6426 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6430 In case of anamorphic video, in order to set the output display aspect
6431 correctly, it is necessary to use @var{sar} in the expression,
6432 according to the relation:
6434 (ih * X / ih) * sar = output_dar
6435 X = output_dar / sar
6438 Thus the previous example needs to be modified to:
6440 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6444 Double the output size and put the input video in the bottom-right
6445 corner of the output padded area:
6447 pad="2*iw:2*ih:ow-iw:oh-ih"
6451 @section perspective
6453 Correct perspective of video not recorded perpendicular to the screen.
6455 A description of the accepted parameters follows.
6466 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6467 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6469 The expressions can use the following variables:
6474 the width and height of video frame.
6478 Set interpolation for perspective correction.
6480 It accepts the following values:
6486 Default value is @samp{linear}.
6491 Delay interlaced video by one field time so that the field order changes.
6493 The intended use is to fix PAL movies that have been captured with the
6494 opposite field order to the film-to-video transfer.
6496 A description of the accepted parameters follows.
6502 It accepts the following values:
6505 Capture field order top-first, transfer bottom-first.
6506 Filter will delay the bottom field.
6509 Capture field order bottom-first, transfer top-first.
6510 Filter will delay the top field.
6513 Capture and transfer with the same field order. This mode only exists
6514 for the documentation of the other options to refer to, but if you
6515 actually select it, the filter will faithfully do nothing.
6518 Capture field order determined automatically by field flags, transfer
6520 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6521 basis using field flags. If no field information is available,
6522 then this works just like @samp{u}.
6525 Capture unknown or varying, transfer opposite.
6526 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6527 analyzing the images and selecting the alternative that produces best
6528 match between the fields.
6531 Capture top-first, transfer unknown or varying.
6532 Filter selects among @samp{t} and @samp{p} using image analysis.
6535 Capture bottom-first, transfer unknown or varying.
6536 Filter selects among @samp{b} and @samp{p} using image analysis.
6539 Capture determined by field flags, transfer unknown or varying.
6540 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6541 image analysis. If no field information is available, then this works just
6542 like @samp{U}. This is the default mode.
6545 Both capture and transfer unknown or varying.
6546 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
6550 @section pixdesctest
6552 Pixel format descriptor test filter, mainly useful for internal
6553 testing. The output video should be equal to the input video.
6557 format=monow, pixdesctest
6560 can be used to test the monowhite pixel format descriptor definition.
6564 Enable the specified chain of postprocessing subfilters using libpostproc. This
6565 library should be automatically selected with a GPL build (@code{--enable-gpl}).
6566 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
6567 Each subfilter and some options have a short and a long name that can be used
6568 interchangeably, i.e. dr/dering are the same.
6570 The filters accept the following options:
6574 Set postprocessing subfilters string.
6577 All subfilters share common options to determine their scope:
6581 Honor the quality commands for this subfilter.
6584 Do chrominance filtering, too (default).
6587 Do luminance filtering only (no chrominance).
6590 Do chrominance filtering only (no luminance).
6593 These options can be appended after the subfilter name, separated by a '|'.
6595 Available subfilters are:
6598 @item hb/hdeblock[|difference[|flatness]]
6599 Horizontal deblocking filter
6602 Difference factor where higher values mean more deblocking (default: @code{32}).
6604 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6607 @item vb/vdeblock[|difference[|flatness]]
6608 Vertical deblocking filter
6611 Difference factor where higher values mean more deblocking (default: @code{32}).
6613 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6616 @item ha/hadeblock[|difference[|flatness]]
6617 Accurate horizontal deblocking filter
6620 Difference factor where higher values mean more deblocking (default: @code{32}).
6622 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6625 @item va/vadeblock[|difference[|flatness]]
6626 Accurate vertical deblocking filter
6629 Difference factor where higher values mean more deblocking (default: @code{32}).
6631 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6635 The horizontal and vertical deblocking filters share the difference and
6636 flatness values so you cannot set different horizontal and vertical
6641 Experimental horizontal deblocking filter
6644 Experimental vertical deblocking filter
6649 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
6652 larger -> stronger filtering
6654 larger -> stronger filtering
6656 larger -> stronger filtering
6659 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
6662 Stretch luminance to @code{0-255}.
6665 @item lb/linblenddeint
6666 Linear blend deinterlacing filter that deinterlaces the given block by
6667 filtering all lines with a @code{(1 2 1)} filter.
6669 @item li/linipoldeint
6670 Linear interpolating deinterlacing filter that deinterlaces the given block by
6671 linearly interpolating every second line.
6673 @item ci/cubicipoldeint
6674 Cubic interpolating deinterlacing filter deinterlaces the given block by
6675 cubically interpolating every second line.
6677 @item md/mediandeint
6678 Median deinterlacing filter that deinterlaces the given block by applying a
6679 median filter to every second line.
6681 @item fd/ffmpegdeint
6682 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
6683 second line with a @code{(-1 4 2 4 -1)} filter.
6686 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
6687 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
6689 @item fq/forceQuant[|quantizer]
6690 Overrides the quantizer table from the input with the constant quantizer you
6698 Default pp filter combination (@code{hb|a,vb|a,dr|a})
6701 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
6704 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
6707 @subsection Examples
6711 Apply horizontal and vertical deblocking, deringing and automatic
6712 brightness/contrast:
6718 Apply default filters without brightness/contrast correction:
6724 Apply default filters and temporal denoiser:
6726 pp=default/tmpnoise|1|2|3
6730 Apply deblocking on luminance only, and switch vertical deblocking on or off
6731 automatically depending on available CPU time:
6739 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
6740 Ratio) between two input videos.
6742 This filter takes in input two input videos, the first input is
6743 considered the "main" source and is passed unchanged to the
6744 output. The second input is used as a "reference" video for computing
6747 Both video inputs must have the same resolution and pixel format for
6748 this filter to work correctly. Also it assumes that both inputs
6749 have the same number of frames, which are compared one by one.
6751 The obtained average PSNR is printed through the logging system.
6753 The filter stores the accumulated MSE (mean squared error) of each
6754 frame, and at the end of the processing it is averaged across all frames
6755 equally, and the following formula is applied to obtain the PSNR:
6758 PSNR = 10*log10(MAX^2/MSE)
6761 Where MAX is the average of the maximum values of each component of the
6764 The description of the accepted parameters follows.
6768 If specified the filter will use the named file to save the PSNR of
6769 each individual frame.
6772 The file printed if @var{stats_file} is selected, contains a sequence of
6773 key/value pairs of the form @var{key}:@var{value} for each compared
6776 A description of each shown parameter follows:
6780 sequential number of the input frame, starting from 1
6783 Mean Square Error pixel-by-pixel average difference of the compared
6784 frames, averaged over all the image components.
6786 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
6787 Mean Square Error pixel-by-pixel average difference of the compared
6788 frames for the component specified by the suffix.
6790 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
6791 Peak Signal to Noise ratio of the compared frames for the component
6792 specified by the suffix.
6797 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
6798 [main][ref] psnr="stats_file=stats.log" [out]
6801 On this example the input file being processed is compared with the
6802 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
6803 is stored in @file{stats.log}.
6808 Pulldown reversal (inverse telecine) filter, capable of handling mixed
6809 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
6812 The pullup filter is designed to take advantage of future context in making
6813 its decisions. This filter is stateless in the sense that it does not lock
6814 onto a pattern to follow, but it instead looks forward to the following
6815 fields in order to identify matches and rebuild progressive frames.
6817 To produce content with an even framerate, insert the fps filter after
6818 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
6819 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
6821 The filter accepts the following options:
6828 These options set the amount of "junk" to ignore at the left, right, top, and
6829 bottom of the image, respectively. Left and right are in units of 8 pixels,
6830 while top and bottom are in units of 2 lines.
6831 The default is 8 pixels on each side.
6834 Set the strict breaks. Setting this option to 1 will reduce the chances of
6835 filter generating an occasional mismatched frame, but it may also cause an
6836 excessive number of frames to be dropped during high motion sequences.
6837 Conversely, setting it to -1 will make filter match fields more easily.
6838 This may help processing of video where there is slight blurring between
6839 the fields, but may also cause there to be interlaced frames in the output.
6840 Default value is @code{0}.
6843 Set the metric plane to use. It accepts the following values:
6849 Use chroma blue plane.
6852 Use chroma red plane.
6855 This option may be set to use chroma plane instead of the default luma plane
6856 for doing filter's computations. This may improve accuracy on very clean
6857 source material, but more likely will decrease accuracy, especially if there
6858 is chroma noise (rainbow effect) or any grayscale video.
6859 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
6860 load and make pullup usable in realtime on slow machines.
6863 For best results (without duplicated frames in the output file) it is
6864 necessary to change the output frame rate. For example, to inverse
6865 telecine NTSC input:
6867 ffmpeg -i input -vf pullup -r 24000/1001 ...
6872 Suppress a TV station logo, using an image file to determine which
6873 pixels comprise the logo. It works by filling in the pixels that
6874 comprise the logo with neighboring pixels.
6876 The filter accepts the following options:
6880 Set the filter bitmap file, which can be any image format supported by
6881 libavformat. The width and height of the image file must match those of the
6882 video stream being processed.
6885 Pixels in the provided bitmap image with a value of zero are not
6886 considered part of the logo, non-zero pixels are considered part of
6887 the logo. If you use white (255) for the logo and black (0) for the
6888 rest, you will be safe. For making the filter bitmap, it is
6889 recommended to take a screen capture of a black frame with the logo
6890 visible, and then using a threshold filter followed by the erode
6891 filter once or twice.
6893 If needed, little splotches can be fixed manually. Remember that if
6894 logo pixels are not covered, the filter quality will be much
6895 reduced. Marking too many pixels as part of the logo does not hurt as
6896 much, but it will increase the amount of blurring needed to cover over
6897 the image and will destroy more information than necessary, and extra
6898 pixels will slow things down on a large logo.
6902 Rotate video by an arbitrary angle expressed in radians.
6904 The filter accepts the following options:
6906 A description of the optional parameters follows.
6909 Set an expression for the angle by which to rotate the input video
6910 clockwise, expressed as a number of radians. A negative value will
6911 result in a counter-clockwise rotation. By default it is set to "0".
6913 This expression is evaluated for each frame.
6916 Set the output width expression, default value is "iw".
6917 This expression is evaluated just once during configuration.
6920 Set the output height expression, default value is "ih".
6921 This expression is evaluated just once during configuration.
6924 Enable bilinear interpolation if set to 1, a value of 0 disables
6925 it. Default value is 1.
6928 Set the color used to fill the output area not covered by the rotated
6929 image. For the generalsyntax of this option, check the "Color" section in the
6930 ffmpeg-utils manual. If the special value "none" is selected then no
6931 background is printed (useful for example if the background is never shown).
6933 Default value is "black".
6936 The expressions for the angle and the output size can contain the
6937 following constants and functions:
6941 sequential number of the input frame, starting from 0. It is always NAN
6942 before the first frame is filtered.
6945 time in seconds of the input frame, it is set to 0 when the filter is
6946 configured. It is always NAN before the first frame is filtered.
6950 horizontal and vertical chroma subsample values. For example for the
6951 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6955 the input video width and height
6959 the output width and height, that is the size of the padded area as
6960 specified by the @var{width} and @var{height} expressions
6964 the minimal width/height required for completely containing the input
6965 video rotated by @var{a} radians.
6967 These are only available when computing the @option{out_w} and
6968 @option{out_h} expressions.
6971 @subsection Examples
6975 Rotate the input by PI/6 radians clockwise:
6981 Rotate the input by PI/6 radians counter-clockwise:
6987 Rotate the input by 45 degrees clockwise:
6993 Apply a constant rotation with period T, starting from an angle of PI/3:
6995 rotate=PI/3+2*PI*t/T
6999 Make the input video rotation oscillating with a period of T
7000 seconds and an amplitude of A radians:
7002 rotate=A*sin(2*PI/T*t)
7006 Rotate the video, output size is chosen so that the whole rotating
7007 input video is always completely contained in the output:
7009 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
7013 Rotate the video, reduce the output size so that no background is ever
7016 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
7020 @subsection Commands
7022 The filter supports the following commands:
7026 Set the angle expression.
7027 The command accepts the same syntax of the corresponding option.
7029 If the specified expression is not valid, it is kept at its current
7035 Apply Shape Adaptive Blur.
7037 The filter accepts the following options:
7040 @item luma_radius, lr
7041 Set luma blur filter strength, must be a value in range 0.1-4.0, default
7042 value is 1.0. A greater value will result in a more blurred image, and
7043 in slower processing.
7045 @item luma_pre_filter_radius, lpfr
7046 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
7049 @item luma_strength, ls
7050 Set luma maximum difference between pixels to still be considered, must
7051 be a value in the 0.1-100.0 range, default value is 1.0.
7053 @item chroma_radius, cr
7054 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
7055 greater value will result in a more blurred image, and in slower
7058 @item chroma_pre_filter_radius, cpfr
7059 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
7061 @item chroma_strength, cs
7062 Set chroma maximum difference between pixels to still be considered,
7063 must be a value in the 0.1-100.0 range.
7066 Each chroma option value, if not explicitly specified, is set to the
7067 corresponding luma option value.
7072 Scale (resize) the input video, using the libswscale library.
7074 The scale filter forces the output display aspect ratio to be the same
7075 of the input, by changing the output sample aspect ratio.
7077 If the input image format is different from the format requested by
7078 the next filter, the scale filter will convert the input to the
7082 The filter accepts the following options, or any of the options
7083 supported by the libswscale scaler.
7085 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
7086 the complete list of scaler options.
7091 Set the output video dimension expression. Default value is the input
7094 If the value is 0, the input width is used for the output.
7096 If one of the values is -1, the scale filter will use a value that
7097 maintains the aspect ratio of the input image, calculated from the
7098 other specified dimension. If both of them are -1, the input size is
7101 If one of the values is -n with n > 1, the scale filter will also use a value
7102 that maintains the aspect ratio of the input image, calculated from the other
7103 specified dimension. After that it will, however, make sure that the calculated
7104 dimension is divisible by n and adjust the value if necessary.
7106 See below for the list of accepted constants for use in the dimension
7110 Set the interlacing mode. It accepts the following values:
7114 Force interlaced aware scaling.
7117 Do not apply interlaced scaling.
7120 Select interlaced aware scaling depending on whether the source frames
7121 are flagged as interlaced or not.
7124 Default value is @samp{0}.
7127 Set libswscale scaling flags. See
7128 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7129 complete list of values. If not explicitly specified the filter applies
7133 Set the video size. For the syntax of this option, check the "Video size"
7134 section in the ffmpeg-utils manual.
7136 @item in_color_matrix
7137 @item out_color_matrix
7138 Set in/output YCbCr color space type.
7140 This allows the autodetected value to be overridden as well as allows forcing
7141 a specific value used for the output and encoder.
7143 If not specified, the color space type depends on the pixel format.
7149 Choose automatically.
7152 Format conforming to International Telecommunication Union (ITU)
7153 Recommendation BT.709.
7156 Set color space conforming to the United States Federal Communications
7157 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7160 Set color space conforming to:
7164 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7167 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7170 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7175 Set color space conforming to SMPTE ST 240:1999.
7180 Set in/output YCbCr sample range.
7182 This allows the autodetected value to be overridden as well as allows forcing
7183 a specific value used for the output and encoder. If not specified, the
7184 range depends on the pixel format. Possible values:
7188 Choose automatically.
7191 Set full range (0-255 in case of 8-bit luma).
7194 Set "MPEG" range (16-235 in case of 8-bit luma).
7197 @item force_original_aspect_ratio
7198 Enable decreasing or increasing output video width or height if necessary to
7199 keep the original aspect ratio. Possible values:
7203 Scale the video as specified and disable this feature.
7206 The output video dimensions will automatically be decreased if needed.
7209 The output video dimensions will automatically be increased if needed.
7213 One useful instance of this option is that when you know a specific device's
7214 maximum allowed resolution, you can use this to limit the output video to
7215 that, while retaining the aspect ratio. For example, device A allows
7216 1280x720 playback, and your video is 1920x800. Using this option (set it to
7217 decrease) and specifying 1280x720 to the command line makes the output
7220 Please note that this is a different thing than specifying -1 for @option{w}
7221 or @option{h}, you still need to specify the output resolution for this option
7226 The values of the @option{w} and @option{h} options are expressions
7227 containing the following constants:
7232 The input width and height
7236 These are the same as @var{in_w} and @var{in_h}.
7240 The output (scaled) width and height
7244 These are the same as @var{out_w} and @var{out_h}
7247 The same as @var{iw} / @var{ih}
7250 input sample aspect ratio
7253 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7257 horizontal and vertical input chroma subsample values. For example for the
7258 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7262 horizontal and vertical output chroma subsample values. For example for the
7263 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7266 @subsection Examples
7270 Scale the input video to a size of 200x100
7275 This is equivalent to:
7286 Specify a size abbreviation for the output size:
7291 which can also be written as:
7297 Scale the input to 2x:
7303 The above is the same as:
7309 Scale the input to 2x with forced interlaced scaling:
7311 scale=2*iw:2*ih:interl=1
7315 Scale the input to half size:
7321 Increase the width, and set the height to the same size:
7334 Increase the height, and set the width to 3/2 of the height:
7336 scale=w=3/2*oh:h=3/5*ih
7340 Increase the size, making the size a multiple of the chroma
7343 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7347 Increase the width to a maximum of 500 pixels,
7348 keeping the same aspect ratio as the input:
7350 scale=w='min(500\, iw*3/2):h=-1'
7354 @section separatefields
7356 The @code{separatefields} takes a frame-based video input and splits
7357 each frame into its components fields, producing a new half height clip
7358 with twice the frame rate and twice the frame count.
7360 This filter use field-dominance information in frame to decide which
7361 of each pair of fields to place first in the output.
7362 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7364 @section setdar, setsar
7366 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7369 This is done by changing the specified Sample (aka Pixel) Aspect
7370 Ratio, according to the following equation:
7372 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7375 Keep in mind that the @code{setdar} filter does not modify the pixel
7376 dimensions of the video frame. Also, the display aspect ratio set by
7377 this filter may be changed by later filters in the filterchain,
7378 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7381 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7382 the filter output video.
7384 Note that as a consequence of the application of this filter, the
7385 output display aspect ratio will change according to the equation
7388 Keep in mind that the sample aspect ratio set by the @code{setsar}
7389 filter may be changed by later filters in the filterchain, e.g. if
7390 another "setsar" or a "setdar" filter is applied.
7392 It accepts the following parameters:
7395 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7396 Set the aspect ratio used by the filter.
7398 The parameter can be a floating point number string, an expression, or
7399 a string of the form @var{num}:@var{den}, where @var{num} and
7400 @var{den} are the numerator and denominator of the aspect ratio. If
7401 the parameter is not specified, it is assumed the value "0".
7402 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7406 Set the maximum integer value to use for expressing numerator and
7407 denominator when reducing the expressed aspect ratio to a rational.
7408 Default value is @code{100}.
7412 The parameter @var{sar} is an expression containing
7413 the following constants:
7417 These are approximated values for the mathematical constants e
7418 (Euler's number), pi (Greek pi), and phi (the golden ratio).
7421 The input width and height.
7424 These are the same as @var{w} / @var{h}.
7427 The input sample aspect ratio.
7430 The input display aspect ratio. It is the same as
7431 (@var{w} / @var{h}) * @var{sar}.
7434 Horizontal and vertical chroma subsample values. For example, for the
7435 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7438 @subsection Examples
7443 To change the display aspect ratio to 16:9, specify one of the following:
7451 To change the sample aspect ratio to 10:11, specify:
7457 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7458 1000 in the aspect ratio reduction, use the command:
7460 setdar=ratio=16/9:max=1000
7468 Force field for the output video frame.
7470 The @code{setfield} filter marks the interlace type field for the
7471 output frames. It does not change the input frame, but only sets the
7472 corresponding property, which affects how the frame is treated by
7473 following filters (e.g. @code{fieldorder} or @code{yadif}).
7475 The filter accepts the following options:
7480 Available values are:
7484 Keep the same field property.
7487 Mark the frame as bottom-field-first.
7490 Mark the frame as top-field-first.
7493 Mark the frame as progressive.
7499 Show a line containing various information for each input video frame.
7500 The input video is not modified.
7502 The shown line contains a sequence of key/value pairs of the form
7503 @var{key}:@var{value}.
7505 It accepts the following parameters:
7509 The (sequential) number of the input frame, starting from 0.
7512 The Presentation TimeStamp of the input frame, expressed as a number of
7513 time base units. The time base unit depends on the filter input pad.
7516 The Presentation TimeStamp of the input frame, expressed as a number of
7520 The position of the frame in the input stream, or -1 if this information is
7521 unavailable and/or meaningless (for example in case of synthetic video).
7524 The pixel format name.
7527 The sample aspect ratio of the input frame, expressed in the form
7528 @var{num}/@var{den}.
7531 The size of the input frame. For the syntax of this option, check the "Video size"
7532 section in the ffmpeg-utils manual.
7535 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
7536 for bottom field first).
7539 This is 1 if the frame is a key frame, 0 otherwise.
7542 The picture type of the input frame ("I" for an I-frame, "P" for a
7543 P-frame, "B" for a B-frame, or "?" for an unknown type).
7544 Also refer to the documentation of the @code{AVPictureType} enum and of
7545 the @code{av_get_picture_type_char} function defined in
7546 @file{libavutil/avutil.h}.
7549 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
7551 @item plane_checksum
7552 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
7553 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
7556 @section shuffleplanes
7558 Reorder and/or duplicate video planes.
7560 It accepts the following parameters:
7565 The index of the input plane to be used as the first output plane.
7568 The index of the input plane to be used as the second output plane.
7571 The index of the input plane to be used as the third output plane.
7574 The index of the input plane to be used as the fourth output plane.
7578 The first plane has the index 0. The default is to keep the input unchanged.
7580 Swap the second and third planes of the input:
7582 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
7585 @section signalstats
7586 Evaluate various visual metrics that assist in determining issues associated
7587 with the digitization of analog video media.
7589 By default the filter will log these metadata values:
7593 Display the minimal Y value contained within the input frame. Expressed in
7597 Display the Y value at the 10% percentile within the input frame. Expressed in
7601 Display the average Y value within the input frame. Expressed in range of
7605 Display the Y value at the 90% percentile within the input frame. Expressed in
7609 Display the maximum Y value contained within the input frame. Expressed in
7613 Display the minimal U value contained within the input frame. Expressed in
7617 Display the U value at the 10% percentile within the input frame. Expressed in
7621 Display the average U value within the input frame. Expressed in range of
7625 Display the U value at the 90% percentile within the input frame. Expressed in
7629 Display the maximum U value contained within the input frame. Expressed in
7633 Display the minimal V value contained within the input frame. Expressed in
7637 Display the V value at the 10% percentile within the input frame. Expressed in
7641 Display the average V value within the input frame. Expressed in range of
7645 Display the V value at the 90% percentile within the input frame. Expressed in
7649 Display the maximum V value contained within the input frame. Expressed in
7653 Display the minimal saturation value contained within the input frame.
7654 Expressed in range of [0-~181.02].
7657 Display the saturation value at the 10% percentile within the input frame.
7658 Expressed in range of [0-~181.02].
7661 Display the average saturation value within the input frame. Expressed in range
7665 Display the saturation value at the 90% percentile within the input frame.
7666 Expressed in range of [0-~181.02].
7669 Display the maximum saturation value contained within the input frame.
7670 Expressed in range of [0-~181.02].
7673 Display the median value for hue within the input frame. Expressed in range of
7677 Display the average value for hue within the input frame. Expressed in range of
7681 Display the average of sample value difference between all values of the Y
7682 plane in the current frame and corresponding values of the previous input frame.
7683 Expressed in range of [0-255].
7686 Display the average of sample value difference between all values of the U
7687 plane in the current frame and corresponding values of the previous input frame.
7688 Expressed in range of [0-255].
7691 Display the average of sample value difference between all values of the V
7692 plane in the current frame and corresponding values of the previous input frame.
7693 Expressed in range of [0-255].
7696 The filter accepts the following options:
7702 @option{stat} specify an additional form of image analysis.
7703 @option{out} output video with the specified type of pixel highlighted.
7705 Both options accept the following values:
7709 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
7710 unlike the neighboring pixels of the same field. Examples of temporal outliers
7711 include the results of video dropouts, head clogs, or tape tracking issues.
7714 Identify @var{vertical line repetition}. Vertical line repetition includes
7715 similar rows of pixels within a frame. In born-digital video vertical line
7716 repetition is common, but this pattern is uncommon in video digitized from an
7717 analog source. When it occurs in video that results from the digitization of an
7718 analog source it can indicate concealment from a dropout compensator.
7721 Identify pixels that fall outside of legal broadcast range.
7725 Set the highlight color for the @option{out} option. The default color is
7729 @subsection Examples
7733 Output data of various video metrics:
7735 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
7739 Output specific data about the minimum and maximum values of the Y plane per frame:
7741 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
7745 Playback video while highlighting pixels that are outside of broadcast range in red.
7747 ffplay example.mov -vf signalstats="out=brng:color=red"
7751 Playback video with signalstats metadata drawn over the frame.
7753 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
7756 The contents of signalstat_drawtext.txt used in the command are:
7759 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
7760 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
7761 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
7762 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
7770 Blur the input video without impacting the outlines.
7772 It accepts the following options:
7775 @item luma_radius, lr
7776 Set the luma radius. The option value must be a float number in
7777 the range [0.1,5.0] that specifies the variance of the gaussian filter
7778 used to blur the image (slower if larger). Default value is 1.0.
7780 @item luma_strength, ls
7781 Set the luma strength. The option value must be a float number
7782 in the range [-1.0,1.0] that configures the blurring. A value included
7783 in [0.0,1.0] will blur the image whereas a value included in
7784 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7786 @item luma_threshold, lt
7787 Set the luma threshold used as a coefficient to determine
7788 whether a pixel should be blurred or not. The option value must be an
7789 integer in the range [-30,30]. A value of 0 will filter all the image,
7790 a value included in [0,30] will filter flat areas and a value included
7791 in [-30,0] will filter edges. Default value is 0.
7793 @item chroma_radius, cr
7794 Set the chroma radius. The option value must be a float number in
7795 the range [0.1,5.0] that specifies the variance of the gaussian filter
7796 used to blur the image (slower if larger). Default value is 1.0.
7798 @item chroma_strength, cs
7799 Set the chroma strength. The option value must be a float number
7800 in the range [-1.0,1.0] that configures the blurring. A value included
7801 in [0.0,1.0] will blur the image whereas a value included in
7802 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7804 @item chroma_threshold, ct
7805 Set the chroma threshold used as a coefficient to determine
7806 whether a pixel should be blurred or not. The option value must be an
7807 integer in the range [-30,30]. A value of 0 will filter all the image,
7808 a value included in [0,30] will filter flat areas and a value included
7809 in [-30,0] will filter edges. Default value is 0.
7812 If a chroma option is not explicitly set, the corresponding luma value
7817 Convert between different stereoscopic image formats.
7819 The filters accept the following options:
7823 Set stereoscopic image format of input.
7825 Available values for input image formats are:
7828 side by side parallel (left eye left, right eye right)
7831 side by side crosseye (right eye left, left eye right)
7834 side by side parallel with half width resolution
7835 (left eye left, right eye right)
7838 side by side crosseye with half width resolution
7839 (right eye left, left eye right)
7842 above-below (left eye above, right eye below)
7845 above-below (right eye above, left eye below)
7848 above-below with half height resolution
7849 (left eye above, right eye below)
7852 above-below with half height resolution
7853 (right eye above, left eye below)
7856 alternating frames (left eye first, right eye second)
7859 alternating frames (right eye first, left eye second)
7861 Default value is @samp{sbsl}.
7865 Set stereoscopic image format of output.
7867 Available values for output image formats are all the input formats as well as:
7870 anaglyph red/blue gray
7871 (red filter on left eye, blue filter on right eye)
7874 anaglyph red/green gray
7875 (red filter on left eye, green filter on right eye)
7878 anaglyph red/cyan gray
7879 (red filter on left eye, cyan filter on right eye)
7882 anaglyph red/cyan half colored
7883 (red filter on left eye, cyan filter on right eye)
7886 anaglyph red/cyan color
7887 (red filter on left eye, cyan filter on right eye)
7890 anaglyph red/cyan color optimized with the least squares projection of dubois
7891 (red filter on left eye, cyan filter on right eye)
7894 anaglyph green/magenta gray
7895 (green filter on left eye, magenta filter on right eye)
7898 anaglyph green/magenta half colored
7899 (green filter on left eye, magenta filter on right eye)
7902 anaglyph green/magenta colored
7903 (green filter on left eye, magenta filter on right eye)
7906 anaglyph green/magenta color optimized with the least squares projection of dubois
7907 (green filter on left eye, magenta filter on right eye)
7910 anaglyph yellow/blue gray
7911 (yellow filter on left eye, blue filter on right eye)
7914 anaglyph yellow/blue half colored
7915 (yellow filter on left eye, blue filter on right eye)
7918 anaglyph yellow/blue colored
7919 (yellow filter on left eye, blue filter on right eye)
7922 anaglyph yellow/blue color optimized with the least squares projection of dubois
7923 (yellow filter on left eye, blue filter on right eye)
7926 interleaved rows (left eye has top row, right eye starts on next row)
7929 interleaved rows (right eye has top row, left eye starts on next row)
7932 mono output (left eye only)
7935 mono output (right eye only)
7938 Default value is @samp{arcd}.
7941 @subsection Examples
7945 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
7951 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
7959 Apply a simple postprocessing filter that compresses and decompresses the image
7960 at several (or - in the case of @option{quality} level @code{6} - all) shifts
7961 and average the results.
7963 The filter accepts the following options:
7967 Set quality. This option defines the number of levels for averaging. It accepts
7968 an integer in the range 0-6. If set to @code{0}, the filter will have no
7969 effect. A value of @code{6} means the higher quality. For each increment of
7970 that value the speed drops by a factor of approximately 2. Default value is
7974 Force a constant quantization parameter. If not set, the filter will use the QP
7975 from the video stream (if available).
7978 Set thresholding mode. Available modes are:
7982 Set hard thresholding (default).
7984 Set soft thresholding (better de-ringing effect, but likely blurrier).
7988 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
7989 option may cause flicker since the B-Frames have often larger QP. Default is
7990 @code{0} (not enabled).
7996 Draw subtitles on top of input video using the libass library.
7998 To enable compilation of this filter you need to configure FFmpeg with
7999 @code{--enable-libass}. This filter also requires a build with libavcodec and
8000 libavformat to convert the passed subtitles file to ASS (Advanced Substation
8001 Alpha) subtitles format.
8003 The filter accepts the following options:
8007 Set the filename of the subtitle file to read. It must be specified.
8010 Specify the size of the original video, the video for which the ASS file
8011 was composed. For the syntax of this option, check the "Video size" section in
8012 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
8013 this is necessary to correctly scale the fonts if the aspect ratio has been
8017 Set subtitles input character encoding. @code{subtitles} filter only. Only
8018 useful if not UTF-8.
8020 @item stream_index, si
8021 Set subtitles stream index. @code{subtitles} filter only.
8024 If the first key is not specified, it is assumed that the first value
8025 specifies the @option{filename}.
8027 For example, to render the file @file{sub.srt} on top of the input
8028 video, use the command:
8033 which is equivalent to:
8035 subtitles=filename=sub.srt
8038 To render the default subtitles stream from file @file{video.mkv}, use:
8043 To render the second subtitles stream from that file, use:
8045 subtitles=video.mkv:si=1
8050 Scale the input by 2x and smooth using the Super2xSaI (Scale and
8051 Interpolate) pixel art scaling algorithm.
8053 Useful for enlarging pixel art images without reducing sharpness.
8060 Apply telecine process to the video.
8062 This filter accepts the following options:
8071 The default value is @code{top}.
8075 A string of numbers representing the pulldown pattern you wish to apply.
8076 The default value is @code{23}.
8080 Some typical patterns:
8085 24p: 2332 (preferred)
8092 24p: 222222222223 ("Euro pulldown")
8098 Select the most representative frame in a given sequence of consecutive frames.
8100 The filter accepts the following options:
8104 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
8105 will pick one of them, and then handle the next batch of @var{n} frames until
8106 the end. Default is @code{100}.
8109 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
8110 value will result in a higher memory usage, so a high value is not recommended.
8112 @subsection Examples
8116 Extract one picture each 50 frames:
8122 Complete example of a thumbnail creation with @command{ffmpeg}:
8124 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
8130 Tile several successive frames together.
8132 The filter accepts the following options:
8137 Set the grid size (i.e. the number of lines and columns). For the syntax of
8138 this option, check the "Video size" section in the ffmpeg-utils manual.
8141 Set the maximum number of frames to render in the given area. It must be less
8142 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
8143 the area will be used.
8146 Set the outer border margin in pixels.
8149 Set the inner border thickness (i.e. the number of pixels between frames). For
8150 more advanced padding options (such as having different values for the edges),
8151 refer to the pad video filter.
8154 Specify the color of the unused areaFor the syntax of this option, check the
8155 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
8159 @subsection Examples
8163 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
8165 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
8167 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
8168 duplicating each output frame to accommodate the originally detected frame
8172 Display @code{5} pictures in an area of @code{3x2} frames,
8173 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
8174 mixed flat and named options:
8176 tile=3x2:nb_frames=5:padding=7:margin=2
8182 Perform various types of temporal field interlacing.
8184 Frames are counted starting from 1, so the first input frame is
8187 The filter accepts the following options:
8192 Specify the mode of the interlacing. This option can also be specified
8193 as a value alone. See below for a list of values for this option.
8195 Available values are:
8199 Move odd frames into the upper field, even into the lower field,
8200 generating a double height frame at half frame rate.
8203 Only output even frames, odd frames are dropped, generating a frame with
8204 unchanged height at half frame rate.
8207 Only output odd frames, even frames are dropped, generating a frame with
8208 unchanged height at half frame rate.
8211 Expand each frame to full height, but pad alternate lines with black,
8212 generating a frame with double height at the same input frame rate.
8214 @item interleave_top, 4
8215 Interleave the upper field from odd frames with the lower field from
8216 even frames, generating a frame with unchanged height at half frame rate.
8218 @item interleave_bottom, 5
8219 Interleave the lower field from odd frames with the upper field from
8220 even frames, generating a frame with unchanged height at half frame rate.
8222 @item interlacex2, 6
8223 Double frame rate with unchanged height. Frames are inserted each
8224 containing the second temporal field from the previous input frame and
8225 the first temporal field from the next input frame. This mode relies on
8226 the top_field_first flag. Useful for interlaced video displays with no
8227 field synchronisation.
8230 Numeric values are deprecated but are accepted for backward
8231 compatibility reasons.
8233 Default mode is @code{merge}.
8236 Specify flags influencing the filter process.
8238 Available value for @var{flags} is:
8241 @item low_pass_filter, vlfp
8242 Enable vertical low-pass filtering in the filter.
8243 Vertical low-pass filtering is required when creating an interlaced
8244 destination from a progressive source which contains high-frequency
8245 vertical detail. Filtering will reduce interlace 'twitter' and Moire
8248 Vertical low-pass filtering can only be enabled for @option{mode}
8249 @var{interleave_top} and @var{interleave_bottom}.
8256 Transpose rows with columns in the input video and optionally flip it.
8258 It accepts the following parameters:
8263 Specify the transposition direction.
8265 Can assume the following values:
8267 @item 0, 4, cclock_flip
8268 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
8276 Rotate by 90 degrees clockwise, that is:
8284 Rotate by 90 degrees counterclockwise, that is:
8291 @item 3, 7, clock_flip
8292 Rotate by 90 degrees clockwise and vertically flip, that is:
8300 For values between 4-7, the transposition is only done if the input
8301 video geometry is portrait and not landscape. These values are
8302 deprecated, the @code{passthrough} option should be used instead.
8304 Numerical values are deprecated, and should be dropped in favor of
8308 Do not apply the transposition if the input geometry matches the one
8309 specified by the specified value. It accepts the following values:
8312 Always apply transposition.
8314 Preserve portrait geometry (when @var{height} >= @var{width}).
8316 Preserve landscape geometry (when @var{width} >= @var{height}).
8319 Default value is @code{none}.
8322 For example to rotate by 90 degrees clockwise and preserve portrait
8325 transpose=dir=1:passthrough=portrait
8328 The command above can also be specified as:
8330 transpose=1:portrait
8334 Trim the input so that the output contains one continuous subpart of the input.
8336 It accepts the following parameters:
8339 Specify the time of the start of the kept section, i.e. the frame with the
8340 timestamp @var{start} will be the first frame in the output.
8343 Specify the time of the first frame that will be dropped, i.e. the frame
8344 immediately preceding the one with the timestamp @var{end} will be the last
8345 frame in the output.
8348 This is the same as @var{start}, except this option sets the start timestamp
8349 in timebase units instead of seconds.
8352 This is the same as @var{end}, except this option sets the end timestamp
8353 in timebase units instead of seconds.
8356 The maximum duration of the output in seconds.
8359 The number of the first frame that should be passed to the output.
8362 The number of the first frame that should be dropped.
8365 @option{start}, @option{end}, @option{duration} are expressed as time
8366 duration specifications, check the "Time duration" section in the
8367 ffmpeg-utils manual.
8369 Note that the first two sets of the start/end options and the @option{duration}
8370 option look at the frame timestamp, while the _frame variants simply count the
8371 frames that pass through the filter. Also note that this filter does not modify
8372 the timestamps. If you wish for the output timestamps to start at zero, insert a
8373 setpts filter after the trim filter.
8375 If multiple start or end options are set, this filter tries to be greedy and
8376 keep all the frames that match at least one of the specified constraints. To keep
8377 only the part that matches all the constraints at once, chain multiple trim
8380 The defaults are such that all the input is kept. So it is possible to set e.g.
8381 just the end values to keep everything before the specified time.
8386 Drop everything except the second minute of input:
8388 ffmpeg -i INPUT -vf trim=60:120
8392 Keep only the first second:
8394 ffmpeg -i INPUT -vf trim=duration=1
8402 Sharpen or blur the input video.
8404 It accepts the following parameters:
8407 @item luma_msize_x, lx
8408 Set the luma matrix horizontal size. It must be an odd integer between
8409 3 and 63. The default value is 5.
8411 @item luma_msize_y, ly
8412 Set the luma matrix vertical size. It must be an odd integer between 3
8413 and 63. The default value is 5.
8415 @item luma_amount, la
8416 Set the luma effect strength. It must be a floating point number, reasonable
8417 values lay between -1.5 and 1.5.
8419 Negative values will blur the input video, while positive values will
8420 sharpen it, a value of zero will disable the effect.
8422 Default value is 1.0.
8424 @item chroma_msize_x, cx
8425 Set the chroma matrix horizontal size. It must be an odd integer
8426 between 3 and 63. The default value is 5.
8428 @item chroma_msize_y, cy
8429 Set the chroma matrix vertical size. It must be an odd integer
8430 between 3 and 63. The default value is 5.
8432 @item chroma_amount, ca
8433 Set the chroma effect strength. It must be a floating point number, reasonable
8434 values lay between -1.5 and 1.5.
8436 Negative values will blur the input video, while positive values will
8437 sharpen it, a value of zero will disable the effect.
8439 Default value is 0.0.
8442 If set to 1, specify using OpenCL capabilities, only available if
8443 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
8447 All parameters are optional and default to the equivalent of the
8448 string '5:5:1.0:5:5:0.0'.
8450 @subsection Examples
8454 Apply strong luma sharpen effect:
8456 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
8460 Apply a strong blur of both luma and chroma parameters:
8462 unsharp=7:7:-2:7:7:-2
8466 @anchor{vidstabdetect}
8467 @section vidstabdetect
8469 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
8470 @ref{vidstabtransform} for pass 2.
8472 This filter generates a file with relative translation and rotation
8473 transform information about subsequent frames, which is then used by
8474 the @ref{vidstabtransform} filter.
8476 To enable compilation of this filter you need to configure FFmpeg with
8477 @code{--enable-libvidstab}.
8479 This filter accepts the following options:
8483 Set the path to the file used to write the transforms information.
8484 Default value is @file{transforms.trf}.
8487 Set how shaky the video is and how quick the camera is. It accepts an
8488 integer in the range 1-10, a value of 1 means little shakiness, a
8489 value of 10 means strong shakiness. Default value is 5.
8492 Set the accuracy of the detection process. It must be a value in the
8493 range 1-15. A value of 1 means low accuracy, a value of 15 means high
8494 accuracy. Default value is 15.
8497 Set stepsize of the search process. The region around minimum is
8498 scanned with 1 pixel resolution. Default value is 6.
8501 Set minimum contrast. Below this value a local measurement field is
8502 discarded. Must be a floating point value in the range 0-1. Default
8506 Set reference frame number for tripod mode.
8508 If enabled, the motion of the frames is compared to a reference frame
8509 in the filtered stream, identified by the specified number. The idea
8510 is to compensate all movements in a more-or-less static scene and keep
8511 the camera view absolutely still.
8513 If set to 0, it is disabled. The frames are counted starting from 1.
8516 Show fields and transforms in the resulting frames. It accepts an
8517 integer in the range 0-2. Default value is 0, which disables any
8521 @subsection Examples
8531 Analyze strongly shaky movie and put the results in file
8532 @file{mytransforms.trf}:
8534 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
8538 Visualize the result of internal transformations in the resulting
8541 vidstabdetect=show=1
8545 Analyze a video with medium shakiness using @command{ffmpeg}:
8547 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
8551 @anchor{vidstabtransform}
8552 @section vidstabtransform
8554 Video stabilization/deshaking: pass 2 of 2,
8555 see @ref{vidstabdetect} for pass 1.
8557 Read a file with transform information for each frame and
8558 apply/compensate them. Together with the @ref{vidstabdetect}
8559 filter this can be used to deshake videos. See also
8560 @url{http://public.hronopik.de/vid.stab}. It is important to also use
8561 the unsharp filter, see below.
8563 To enable compilation of this filter you need to configure FFmpeg with
8564 @code{--enable-libvidstab}.
8570 Set path to the file used to read the transforms. Default value is
8571 @file{transforms.trf}).
8574 Set the number of frames (value*2 + 1) used for lowpass filtering the
8575 camera movements. Default value is 10.
8577 For example a number of 10 means that 21 frames are used (10 in the
8578 past and 10 in the future) to smoothen the motion in the video. A
8579 larger values leads to a smoother video, but limits the acceleration
8580 of the camera (pan/tilt movements). 0 is a special case where a
8581 static camera is simulated.
8584 Set the camera path optimization algorithm.
8586 Accepted values are:
8589 gaussian kernel low-pass filter on camera motion (default)
8591 averaging on transformations
8595 Set maximal number of pixels to translate frames. Default value is -1,
8599 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
8600 value is -1, meaning no limit.
8603 Specify how to deal with borders that may be visible due to movement
8606 Available values are:
8609 keep image information from previous frame (default)
8611 fill the border black
8615 Invert transforms if set to 1. Default value is 0.
8618 Consider transforms as relative to previsou frame if set to 1,
8619 absolute if set to 0. Default value is 0.
8622 Set percentage to zoom. A positive value will result in a zoom-in
8623 effect, a negative value in a zoom-out effect. Default value is 0 (no
8627 Set optimal zooming to avoid borders.
8629 Accepted values are:
8634 optimal static zoom value is determined (only very strong movements
8635 will lead to visible borders) (default)
8637 optimal adaptive zoom value is determined (no borders will be
8638 visible), see @option{zoomspeed}
8641 Note that the value given at zoom is added to the one calculated here.
8644 Set percent to zoom maximally each frame (enabled when
8645 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
8649 Specify type of interpolation.
8651 Available values are:
8656 linear only horizontal
8658 linear in both directions (default)
8660 cubic in both directions (slow)
8664 Enable virtual tripod mode if set to 1, which is equivalent to
8665 @code{relative=0:smoothing=0}. Default value is 0.
8667 Use also @code{tripod} option of @ref{vidstabdetect}.
8670 Increase log verbosity if set to 1. Also the detected global motions
8671 are written to the temporary file @file{global_motions.trf}. Default
8675 @subsection Examples
8679 Use @command{ffmpeg} for a typical stabilization with default values:
8681 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
8684 Note the use of the unsharp filter which is always recommended.
8687 Zoom in a bit more and load transform data from a given file:
8689 vidstabtransform=zoom=5:input="mytransforms.trf"
8693 Smoothen the video even more:
8695 vidstabtransform=smoothing=30
8701 Flip the input video vertically.
8703 For example, to vertically flip a video with @command{ffmpeg}:
8705 ffmpeg -i in.avi -vf "vflip" out.avi
8710 Make or reverse a natural vignetting effect.
8712 The filter accepts the following options:
8716 Set lens angle expression as a number of radians.
8718 The value is clipped in the @code{[0,PI/2]} range.
8720 Default value: @code{"PI/5"}
8724 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
8728 Set forward/backward mode.
8730 Available modes are:
8733 The larger the distance from the central point, the darker the image becomes.
8736 The larger the distance from the central point, the brighter the image becomes.
8737 This can be used to reverse a vignette effect, though there is no automatic
8738 detection to extract the lens @option{angle} and other settings (yet). It can
8739 also be used to create a burning effect.
8742 Default value is @samp{forward}.
8745 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
8747 It accepts the following values:
8750 Evaluate expressions only once during the filter initialization.
8753 Evaluate expressions for each incoming frame. This is way slower than the
8754 @samp{init} mode since it requires all the scalers to be re-computed, but it
8755 allows advanced dynamic expressions.
8758 Default value is @samp{init}.
8761 Set dithering to reduce the circular banding effects. Default is @code{1}
8765 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
8766 Setting this value to the SAR of the input will make a rectangular vignetting
8767 following the dimensions of the video.
8769 Default is @code{1/1}.
8772 @subsection Expressions
8774 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
8775 following parameters.
8780 input width and height
8783 the number of input frame, starting from 0
8786 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
8787 @var{TB} units, NAN if undefined
8790 frame rate of the input video, NAN if the input frame rate is unknown
8793 the PTS (Presentation TimeStamp) of the filtered video frame,
8794 expressed in seconds, NAN if undefined
8797 time base of the input video
8801 @subsection Examples
8805 Apply simple strong vignetting effect:
8811 Make a flickering vignetting:
8813 vignette='PI/4+random(1)*PI/50':eval=frame
8820 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
8821 Deinterlacing Filter").
8823 Based on the process described by Martin Weston for BBC R&D, and
8824 implemented based on the de-interlace algorithm written by Jim
8825 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
8826 uses filter coefficients calculated by BBC R&D.
8828 There are two sets of filter coefficients, so called "simple":
8829 and "complex". Which set of filter coefficients is used can
8830 be set by passing an optional parameter:
8834 Set the interlacing filter coefficients. Accepts one of the following values:
8838 Simple filter coefficient set.
8840 More-complex filter coefficient set.
8842 Default value is @samp{complex}.
8845 Specify which frames to deinterlace. Accept one of the following values:
8849 Deinterlace all frames,
8851 Only deinterlace frames marked as interlaced.
8854 Default value is @samp{all}.
8860 Deinterlace the input video ("yadif" means "yet another deinterlacing
8863 It accepts the following parameters:
8869 The interlacing mode to adopt. It accepts one of the following values:
8873 Output one frame for each frame.
8875 Output one frame for each field.
8876 @item 2, send_frame_nospatial
8877 Like @code{send_frame}, but it skips the spatial interlacing check.
8878 @item 3, send_field_nospatial
8879 Like @code{send_field}, but it skips the spatial interlacing check.
8882 The default value is @code{send_frame}.
8885 The picture field parity assumed for the input interlaced video. It accepts one
8886 of the following values:
8890 Assume the top field is first.
8892 Assume the bottom field is first.
8894 Enable automatic detection of field parity.
8897 The default value is @code{auto}.
8898 If the interlacing is unknown or the decoder does not export this information,
8899 top field first will be assumed.
8902 Specify which frames to deinterlace. Accept one of the following
8907 Deinterlace all frames.
8909 Only deinterlace frames marked as interlaced.
8912 The default value is @code{all}.
8917 Apply Zoom & Pan effect.
8919 This filter accepts the following options:
8923 Set the zoom expression. Default is 1.
8927 Set the x and y expression. Default is 0.
8930 Set the duration expression in number of frames.
8931 This sets for how many number of frames effect will last for
8935 Set the output image size, default is 'hd720'.
8938 Each expression can contain the following constants:
8961 Last calculated 'x' and 'y' position from 'x' and 'y' expression
8962 for current input frame.
8966 'x' and 'y' of last output frame of previous input frame or 0 when there was
8967 not yet such frame (first input frame).
8970 Last calculated zoom from 'z' expression for current input frame.
8973 Last calculated zoom of last output frame of previous input frame.
8976 Number of output frames for current input frame. Calculated from 'd' expression
8977 for each input frame.
8980 number of output frames created for previous input frame
8983 Rational number: input width / input height
8989 display aspect ratio
8993 @subsection Examples
8997 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
8999 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
9003 @c man end VIDEO FILTERS
9005 @chapter Video Sources
9006 @c man begin VIDEO SOURCES
9008 Below is a description of the currently available video sources.
9012 Buffer video frames, and make them available to the filter chain.
9014 This source is mainly intended for a programmatic use, in particular
9015 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
9017 It accepts the following parameters:
9022 Specify the size (width and height) of the buffered video frames. For the
9023 syntax of this option, check the "Video size" section in the ffmpeg-utils
9027 The input video width.
9030 The input video height.
9033 A string representing the pixel format of the buffered video frames.
9034 It may be a number corresponding to a pixel format, or a pixel format
9038 Specify the timebase assumed by the timestamps of the buffered frames.
9041 Specify the frame rate expected for the video stream.
9043 @item pixel_aspect, sar
9044 The sample (pixel) aspect ratio of the input video.
9047 Specify the optional parameters to be used for the scale filter which
9048 is automatically inserted when an input change is detected in the
9049 input size or format.
9054 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
9057 will instruct the source to accept video frames with size 320x240 and
9058 with format "yuv410p", assuming 1/24 as the timestamps timebase and
9059 square pixels (1:1 sample aspect ratio).
9060 Since the pixel format with name "yuv410p" corresponds to the number 6
9061 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
9062 this example corresponds to:
9064 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
9067 Alternatively, the options can be specified as a flat string, but this
9068 syntax is deprecated:
9070 @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}]
9074 Create a pattern generated by an elementary cellular automaton.
9076 The initial state of the cellular automaton can be defined through the
9077 @option{filename}, and @option{pattern} options. If such options are
9078 not specified an initial state is created randomly.
9080 At each new frame a new row in the video is filled with the result of
9081 the cellular automaton next generation. The behavior when the whole
9082 frame is filled is defined by the @option{scroll} option.
9084 This source accepts the following options:
9088 Read the initial cellular automaton state, i.e. the starting row, from
9090 In the file, each non-whitespace character is considered an alive
9091 cell, a newline will terminate the row, and further characters in the
9092 file will be ignored.
9095 Read the initial cellular automaton state, i.e. the starting row, from
9096 the specified string.
9098 Each non-whitespace character in the string is considered an alive
9099 cell, a newline will terminate the row, and further characters in the
9100 string will be ignored.
9103 Set the video rate, that is the number of frames generated per second.
9106 @item random_fill_ratio, ratio
9107 Set the random fill ratio for the initial cellular automaton row. It
9108 is a floating point number value ranging from 0 to 1, defaults to
9111 This option is ignored when a file or a pattern is specified.
9113 @item random_seed, seed
9114 Set the seed for filling randomly the initial row, must be an integer
9115 included between 0 and UINT32_MAX. If not specified, or if explicitly
9116 set to -1, the filter will try to use a good random seed on a best
9120 Set the cellular automaton rule, it is a number ranging from 0 to 255.
9121 Default value is 110.
9124 Set the size of the output video. For the syntax of this option, check
9125 the "Video size" section in the ffmpeg-utils manual.
9127 If @option{filename} or @option{pattern} is specified, the size is set
9128 by default to the width of the specified initial state row, and the
9129 height is set to @var{width} * PHI.
9131 If @option{size} is set, it must contain the width of the specified
9132 pattern string, and the specified pattern will be centered in the
9135 If a filename or a pattern string is not specified, the size value
9136 defaults to "320x518" (used for a randomly generated initial state).
9139 If set to 1, scroll the output upward when all the rows in the output
9140 have been already filled. If set to 0, the new generated row will be
9141 written over the top row just after the bottom row is filled.
9144 @item start_full, full
9145 If set to 1, completely fill the output with generated rows before
9146 outputting the first frame.
9147 This is the default behavior, for disabling set the value to 0.
9150 If set to 1, stitch the left and right row edges together.
9151 This is the default behavior, for disabling set the value to 0.
9154 @subsection Examples
9158 Read the initial state from @file{pattern}, and specify an output of
9161 cellauto=f=pattern:s=200x400
9165 Generate a random initial row with a width of 200 cells, with a fill
9168 cellauto=ratio=2/3:s=200x200
9172 Create a pattern generated by rule 18 starting by a single alive cell
9173 centered on an initial row with width 100:
9175 cellauto=p=@@:s=100x400:full=0:rule=18
9179 Specify a more elaborated initial pattern:
9181 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
9188 Generate a Mandelbrot set fractal, and progressively zoom towards the
9189 point specified with @var{start_x} and @var{start_y}.
9191 This source accepts the following options:
9196 Set the terminal pts value. Default value is 400.
9199 Set the terminal scale value.
9200 Must be a floating point value. Default value is 0.3.
9203 Set the inner coloring mode, that is the algorithm used to draw the
9204 Mandelbrot fractal internal region.
9206 It shall assume one of the following values:
9211 Show time until convergence.
9213 Set color based on point closest to the origin of the iterations.
9218 Default value is @var{mincol}.
9221 Set the bailout value. Default value is 10.0.
9224 Set the maximum of iterations performed by the rendering
9225 algorithm. Default value is 7189.
9228 Set outer coloring mode.
9229 It shall assume one of following values:
9231 @item iteration_count
9232 Set iteration cound mode.
9233 @item normalized_iteration_count
9234 set normalized iteration count mode.
9236 Default value is @var{normalized_iteration_count}.
9239 Set frame rate, expressed as number of frames per second. Default
9243 Set frame size. For the syntax of this option, check the "Video
9244 size" section in the ffmpeg-utils manual. Default value is "640x480".
9247 Set the initial scale value. Default value is 3.0.
9250 Set the initial x position. Must be a floating point value between
9251 -100 and 100. Default value is -0.743643887037158704752191506114774.
9254 Set the initial y position. Must be a floating point value between
9255 -100 and 100. Default value is -0.131825904205311970493132056385139.
9260 Generate various test patterns, as generated by the MPlayer test filter.
9262 The size of the generated video is fixed, and is 256x256.
9263 This source is useful in particular for testing encoding features.
9265 This source accepts the following options:
9270 Specify the frame rate of the sourced video, as the number of frames
9271 generated per second. It has to be a string in the format
9272 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9273 number or a valid video frame rate abbreviation. The default value is
9277 Set the video duration of the sourced video. The accepted syntax is:
9282 See also the function @code{av_parse_time()}.
9284 If not specified, or the expressed duration is negative, the video is
9285 supposed to be generated forever.
9289 Set the number or the name of the test to perform. Supported tests are:
9305 Default value is "all", which will cycle through the list of all tests.
9313 will generate a "dc_luma" test pattern.
9317 Provide a frei0r source.
9319 To enable compilation of this filter you need to install the frei0r
9320 header and configure FFmpeg with @code{--enable-frei0r}.
9322 This source accepts the following parameters:
9327 The size of the video to generate. For the syntax of this option, check the
9328 "Video size" section in the ffmpeg-utils manual.
9331 The framerate of the generated video. It may be a string of the form
9332 @var{num}/@var{den} or a frame rate abbreviation.
9335 The name to the frei0r source to load. For more information regarding frei0r and
9336 how to set the parameters, read the @ref{frei0r} section in the video filters
9340 A '|'-separated list of parameters to pass to the frei0r source.
9344 For example, to generate a frei0r partik0l source with size 200x200
9345 and frame rate 10 which is overlayed on the overlay filter main input:
9347 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
9352 Generate a life pattern.
9354 This source is based on a generalization of John Conway's life game.
9356 The sourced input represents a life grid, each pixel represents a cell
9357 which can be in one of two possible states, alive or dead. Every cell
9358 interacts with its eight neighbours, which are the cells that are
9359 horizontally, vertically, or diagonally adjacent.
9361 At each interaction the grid evolves according to the adopted rule,
9362 which specifies the number of neighbor alive cells which will make a
9363 cell stay alive or born. The @option{rule} option allows one to specify
9366 This source accepts the following options:
9370 Set the file from which to read the initial grid state. In the file,
9371 each non-whitespace character is considered an alive cell, and newline
9372 is used to delimit the end of each row.
9374 If this option is not specified, the initial grid is generated
9378 Set the video rate, that is the number of frames generated per second.
9381 @item random_fill_ratio, ratio
9382 Set the random fill ratio for the initial random grid. It is a
9383 floating point number value ranging from 0 to 1, defaults to 1/PHI.
9384 It is ignored when a file is specified.
9386 @item random_seed, seed
9387 Set the seed for filling the initial random grid, must be an integer
9388 included between 0 and UINT32_MAX. If not specified, or if explicitly
9389 set to -1, the filter will try to use a good random seed on a best
9395 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
9396 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
9397 @var{NS} specifies the number of alive neighbor cells which make a
9398 live cell stay alive, and @var{NB} the number of alive neighbor cells
9399 which make a dead cell to become alive (i.e. to "born").
9400 "s" and "b" can be used in place of "S" and "B", respectively.
9402 Alternatively a rule can be specified by an 18-bits integer. The 9
9403 high order bits are used to encode the next cell state if it is alive
9404 for each number of neighbor alive cells, the low order bits specify
9405 the rule for "borning" new cells. Higher order bits encode for an
9406 higher number of neighbor cells.
9407 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
9408 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
9410 Default value is "S23/B3", which is the original Conway's game of life
9411 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
9412 cells, and will born a new cell if there are three alive cells around
9416 Set the size of the output video. For the syntax of this option, check the
9417 "Video size" section in the ffmpeg-utils manual.
9419 If @option{filename} is specified, the size is set by default to the
9420 same size of the input file. If @option{size} is set, it must contain
9421 the size specified in the input file, and the initial grid defined in
9422 that file is centered in the larger resulting area.
9424 If a filename is not specified, the size value defaults to "320x240"
9425 (used for a randomly generated initial grid).
9428 If set to 1, stitch the left and right grid edges together, and the
9429 top and bottom edges also. Defaults to 1.
9432 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
9433 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
9434 value from 0 to 255.
9437 Set the color of living (or new born) cells.
9440 Set the color of dead cells. If @option{mold} is set, this is the first color
9441 used to represent a dead cell.
9444 Set mold color, for definitely dead and moldy cells.
9446 For the syntax of these 3 color options, check the "Color" section in the
9447 ffmpeg-utils manual.
9450 @subsection Examples
9454 Read a grid from @file{pattern}, and center it on a grid of size
9457 life=f=pattern:s=300x300
9461 Generate a random grid of size 200x200, with a fill ratio of 2/3:
9463 life=ratio=2/3:s=200x200
9467 Specify a custom rule for evolving a randomly generated grid:
9473 Full example with slow death effect (mold) using @command{ffplay}:
9475 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
9480 @anchor{haldclutsrc}
9484 @anchor{smptehdbars}
9486 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
9488 The @code{color} source provides an uniformly colored input.
9490 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
9491 @ref{haldclut} filter.
9493 The @code{nullsrc} source returns unprocessed video frames. It is
9494 mainly useful to be employed in analysis / debugging tools, or as the
9495 source for filters which ignore the input data.
9497 The @code{rgbtestsrc} source generates an RGB test pattern useful for
9498 detecting RGB vs BGR issues. You should see a red, green and blue
9499 stripe from top to bottom.
9501 The @code{smptebars} source generates a color bars pattern, based on
9502 the SMPTE Engineering Guideline EG 1-1990.
9504 The @code{smptehdbars} source generates a color bars pattern, based on
9505 the SMPTE RP 219-2002.
9507 The @code{testsrc} source generates a test video pattern, showing a
9508 color pattern, a scrolling gradient and a timestamp. This is mainly
9509 intended for testing purposes.
9511 The sources accept the following parameters:
9516 Specify the color of the source, only available in the @code{color}
9517 source. For the syntax of this option, check the "Color" section in the
9518 ffmpeg-utils manual.
9521 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
9522 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
9523 pixels to be used as identity matrix for 3D lookup tables. Each component is
9524 coded on a @code{1/(N*N)} scale.
9527 Specify the size of the sourced video. For the syntax of this option, check the
9528 "Video size" section in the ffmpeg-utils manual. The default value is
9531 This option is not available with the @code{haldclutsrc} filter.
9534 Specify the frame rate of the sourced video, as the number of frames
9535 generated per second. It has to be a string in the format
9536 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9537 number or a valid video frame rate abbreviation. The default value is
9541 Set the sample aspect ratio of the sourced video.
9544 Set the video duration of the sourced video. The accepted syntax is:
9546 [-]HH[:MM[:SS[.m...]]]
9549 Also see the the @code{av_parse_time()} function.
9551 If not specified, or the expressed duration is negative, the video is
9552 supposed to be generated forever.
9555 Set the number of decimals to show in the timestamp, only available in the
9556 @code{testsrc} source.
9558 The displayed timestamp value will correspond to the original
9559 timestamp value multiplied by the power of 10 of the specified
9560 value. Default value is 0.
9563 For example the following:
9565 testsrc=duration=5.3:size=qcif:rate=10
9568 will generate a video with a duration of 5.3 seconds, with size
9569 176x144 and a frame rate of 10 frames per second.
9571 The following graph description will generate a red source
9572 with an opacity of 0.2, with size "qcif" and a frame rate of 10
9575 color=c=red@@0.2:s=qcif:r=10
9578 If the input content is to be ignored, @code{nullsrc} can be used. The
9579 following command generates noise in the luminance plane by employing
9580 the @code{geq} filter:
9582 nullsrc=s=256x256, geq=random(1)*255:128:128
9585 @subsection Commands
9587 The @code{color} source supports the following commands:
9591 Set the color of the created image. Accepts the same syntax of the
9592 corresponding @option{color} option.
9595 @c man end VIDEO SOURCES
9597 @chapter Video Sinks
9598 @c man begin VIDEO SINKS
9600 Below is a description of the currently available video sinks.
9604 Buffer video frames, and make them available to the end of the filter
9607 This sink is mainly intended for programmatic use, in particular
9608 through the interface defined in @file{libavfilter/buffersink.h}
9609 or the options system.
9611 It accepts a pointer to an AVBufferSinkContext structure, which
9612 defines the incoming buffers' formats, to be passed as the opaque
9613 parameter to @code{avfilter_init_filter} for initialization.
9617 Null video sink: do absolutely nothing with the input video. It is
9618 mainly useful as a template and for use in analysis / debugging
9621 @c man end VIDEO SINKS
9623 @chapter Multimedia Filters
9624 @c man begin MULTIMEDIA FILTERS
9626 Below is a description of the currently available multimedia filters.
9628 @section avectorscope
9630 Convert input audio to a video output, representing the audio vector
9633 The filter is used to measure the difference between channels of stereo
9634 audio stream. A monoaural signal, consisting of identical left and right
9635 signal, results in straight vertical line. Any stereo separation is visible
9636 as a deviation from this line, creating a Lissajous figure.
9637 If the straight (or deviation from it) but horizontal line appears this
9638 indicates that the left and right channels are out of phase.
9640 The filter accepts the following options:
9644 Set the vectorscope mode.
9646 Available values are:
9649 Lissajous rotated by 45 degrees.
9652 Same as above but not rotated.
9655 Default value is @samp{lissajous}.
9658 Set the video size for the output. For the syntax of this option, check the "Video size"
9659 section in the ffmpeg-utils manual. Default value is @code{400x400}.
9662 Set the output frame rate. Default value is @code{25}.
9667 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
9668 Allowed range is @code{[0, 255]}.
9673 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
9674 Allowed range is @code{[0, 255]}.
9677 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
9680 @subsection Examples
9684 Complete example using @command{ffplay}:
9686 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9687 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
9693 Concatenate audio and video streams, joining them together one after the
9696 The filter works on segments of synchronized video and audio streams. All
9697 segments must have the same number of streams of each type, and that will
9698 also be the number of streams at output.
9700 The filter accepts the following options:
9705 Set the number of segments. Default is 2.
9708 Set the number of output video streams, that is also the number of video
9709 streams in each segment. Default is 1.
9712 Set the number of output audio streams, that is also the number of audio
9713 streams in each segment. Default is 0.
9716 Activate unsafe mode: do not fail if segments have a different format.
9720 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
9721 @var{a} audio outputs.
9723 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
9724 segment, in the same order as the outputs, then the inputs for the second
9727 Related streams do not always have exactly the same duration, for various
9728 reasons including codec frame size or sloppy authoring. For that reason,
9729 related synchronized streams (e.g. a video and its audio track) should be
9730 concatenated at once. The concat filter will use the duration of the longest
9731 stream in each segment (except the last one), and if necessary pad shorter
9732 audio streams with silence.
9734 For this filter to work correctly, all segments must start at timestamp 0.
9736 All corresponding streams must have the same parameters in all segments; the
9737 filtering system will automatically select a common pixel format for video
9738 streams, and a common sample format, sample rate and channel layout for
9739 audio streams, but other settings, such as resolution, must be converted
9740 explicitly by the user.
9742 Different frame rates are acceptable but will result in variable frame rate
9743 at output; be sure to configure the output file to handle it.
9745 @subsection Examples
9749 Concatenate an opening, an episode and an ending, all in bilingual version
9750 (video in stream 0, audio in streams 1 and 2):
9752 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
9753 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
9754 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
9755 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
9759 Concatenate two parts, handling audio and video separately, using the
9760 (a)movie sources, and adjusting the resolution:
9762 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
9763 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
9764 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
9766 Note that a desync will happen at the stitch if the audio and video streams
9767 do not have exactly the same duration in the first file.
9773 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
9774 it unchanged. By default, it logs a message at a frequency of 10Hz with the
9775 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
9776 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
9778 The filter also has a video output (see the @var{video} option) with a real
9779 time graph to observe the loudness evolution. The graphic contains the logged
9780 message mentioned above, so it is not printed anymore when this option is set,
9781 unless the verbose logging is set. The main graphing area contains the
9782 short-term loudness (3 seconds of analysis), and the gauge on the right is for
9783 the momentary loudness (400 milliseconds).
9785 More information about the Loudness Recommendation EBU R128 on
9786 @url{http://tech.ebu.ch/loudness}.
9788 The filter accepts the following options:
9793 Activate the video output. The audio stream is passed unchanged whether this
9794 option is set or no. The video stream will be the first output stream if
9795 activated. Default is @code{0}.
9798 Set the video size. This option is for video only. For the syntax of this
9799 option, check the "Video size" section in the ffmpeg-utils manual. Default
9800 and minimum resolution is @code{640x480}.
9803 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
9804 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
9805 other integer value between this range is allowed.
9808 Set metadata injection. If set to @code{1}, the audio input will be segmented
9809 into 100ms output frames, each of them containing various loudness information
9810 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
9812 Default is @code{0}.
9815 Force the frame logging level.
9817 Available values are:
9820 information logging level
9822 verbose logging level
9825 By default, the logging level is set to @var{info}. If the @option{video} or
9826 the @option{metadata} options are set, it switches to @var{verbose}.
9831 Available modes can be cumulated (the option is a @code{flag} type). Possible
9835 Disable any peak mode (default).
9837 Enable sample-peak mode.
9839 Simple peak mode looking for the higher sample value. It logs a message
9840 for sample-peak (identified by @code{SPK}).
9842 Enable true-peak mode.
9844 If enabled, the peak lookup is done on an over-sampled version of the input
9845 stream for better peak accuracy. It logs a message for true-peak.
9846 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
9847 This mode requires a build with @code{libswresample}.
9852 @subsection Examples
9856 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
9858 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
9862 Run an analysis with @command{ffmpeg}:
9864 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
9868 @section interleave, ainterleave
9870 Temporally interleave frames from several inputs.
9872 @code{interleave} works with video inputs, @code{ainterleave} with audio.
9874 These filters read frames from several inputs and send the oldest
9875 queued frame to the output.
9877 Input streams must have a well defined, monotonically increasing frame
9880 In order to submit one frame to output, these filters need to enqueue
9881 at least one frame for each input, so they cannot work in case one
9882 input is not yet terminated and will not receive incoming frames.
9884 For example consider the case when one input is a @code{select} filter
9885 which always drop input frames. The @code{interleave} filter will keep
9886 reading from that input, but it will never be able to send new frames
9887 to output until the input will send an end-of-stream signal.
9889 Also, depending on inputs synchronization, the filters will drop
9890 frames in case one input receives more frames than the other ones, and
9891 the queue is already filled.
9893 These filters accept the following options:
9897 Set the number of different inputs, it is 2 by default.
9900 @subsection Examples
9904 Interleave frames belonging to different streams using @command{ffmpeg}:
9906 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
9910 Add flickering blur effect:
9912 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
9916 @section perms, aperms
9918 Set read/write permissions for the output frames.
9920 These filters are mainly aimed at developers to test direct path in the
9921 following filter in the filtergraph.
9923 The filters accept the following options:
9927 Select the permissions mode.
9929 It accepts the following values:
9932 Do nothing. This is the default.
9934 Set all the output frames read-only.
9936 Set all the output frames directly writable.
9938 Make the frame read-only if writable, and writable if read-only.
9940 Set each output frame read-only or writable randomly.
9944 Set the seed for the @var{random} mode, must be an integer included between
9945 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
9946 @code{-1}, the filter will try to use a good random seed on a best effort
9950 Note: in case of auto-inserted filter between the permission filter and the
9951 following one, the permission might not be received as expected in that
9952 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
9953 perms/aperms filter can avoid this problem.
9955 @section select, aselect
9957 Select frames to pass in output.
9959 This filter accepts the following options:
9964 Set expression, which is evaluated for each input frame.
9966 If the expression is evaluated to zero, the frame is discarded.
9968 If the evaluation result is negative or NaN, the frame is sent to the
9969 first output; otherwise it is sent to the output with index
9970 @code{ceil(val)-1}, assuming that the input index starts from 0.
9972 For example a value of @code{1.2} corresponds to the output with index
9973 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
9976 Set the number of outputs. The output to which to send the selected
9977 frame is based on the result of the evaluation. Default value is 1.
9980 The expression can contain the following constants:
9984 The (sequential) number of the filtered frame, starting from 0.
9987 The (sequential) number of the selected frame, starting from 0.
9989 @item prev_selected_n
9990 The sequential number of the last selected frame. It's NAN if undefined.
9993 The timebase of the input timestamps.
9996 The PTS (Presentation TimeStamp) of the filtered video frame,
9997 expressed in @var{TB} units. It's NAN if undefined.
10000 The PTS of the filtered video frame,
10001 expressed in seconds. It's NAN if undefined.
10004 The PTS of the previously filtered video frame. It's NAN if undefined.
10006 @item prev_selected_pts
10007 The PTS of the last previously filtered video frame. It's NAN if undefined.
10009 @item prev_selected_t
10010 The PTS of the last previously selected video frame. It's NAN if undefined.
10013 The PTS of the first video frame in the video. It's NAN if undefined.
10016 The time of the first video frame in the video. It's NAN if undefined.
10018 @item pict_type @emph{(video only)}
10019 The type of the filtered frame. It can assume one of the following
10031 @item interlace_type @emph{(video only)}
10032 The frame interlace type. It can assume one of the following values:
10035 The frame is progressive (not interlaced).
10037 The frame is top-field-first.
10039 The frame is bottom-field-first.
10042 @item consumed_sample_n @emph{(audio only)}
10043 the number of selected samples before the current frame
10045 @item samples_n @emph{(audio only)}
10046 the number of samples in the current frame
10048 @item sample_rate @emph{(audio only)}
10049 the input sample rate
10052 This is 1 if the filtered frame is a key-frame, 0 otherwise.
10055 the position in the file of the filtered frame, -1 if the information
10056 is not available (e.g. for synthetic video)
10058 @item scene @emph{(video only)}
10059 value between 0 and 1 to indicate a new scene; a low value reflects a low
10060 probability for the current frame to introduce a new scene, while a higher
10061 value means the current frame is more likely to be one (see the example below)
10065 The default value of the select expression is "1".
10067 @subsection Examples
10071 Select all frames in input:
10076 The example above is the same as:
10088 Select only I-frames:
10090 select='eq(pict_type\,I)'
10094 Select one frame every 100:
10096 select='not(mod(n\,100))'
10100 Select only frames contained in the 10-20 time interval:
10102 select=between(t\,10\,20)
10106 Select only I frames contained in the 10-20 time interval:
10108 select=between(t\,10\,20)*eq(pict_type\,I)
10112 Select frames with a minimum distance of 10 seconds:
10114 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
10118 Use aselect to select only audio frames with samples number > 100:
10120 aselect='gt(samples_n\,100)'
10124 Create a mosaic of the first scenes:
10126 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
10129 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
10133 Send even and odd frames to separate outputs, and compose them:
10135 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
10139 @section sendcmd, asendcmd
10141 Send commands to filters in the filtergraph.
10143 These filters read commands to be sent to other filters in the
10146 @code{sendcmd} must be inserted between two video filters,
10147 @code{asendcmd} must be inserted between two audio filters, but apart
10148 from that they act the same way.
10150 The specification of commands can be provided in the filter arguments
10151 with the @var{commands} option, or in a file specified by the
10152 @var{filename} option.
10154 These filters accept the following options:
10157 Set the commands to be read and sent to the other filters.
10159 Set the filename of the commands to be read and sent to the other
10163 @subsection Commands syntax
10165 A commands description consists of a sequence of interval
10166 specifications, comprising a list of commands to be executed when a
10167 particular event related to that interval occurs. The occurring event
10168 is typically the current frame time entering or leaving a given time
10171 An interval is specified by the following syntax:
10173 @var{START}[-@var{END}] @var{COMMANDS};
10176 The time interval is specified by the @var{START} and @var{END} times.
10177 @var{END} is optional and defaults to the maximum time.
10179 The current frame time is considered within the specified interval if
10180 it is included in the interval [@var{START}, @var{END}), that is when
10181 the time is greater or equal to @var{START} and is lesser than
10184 @var{COMMANDS} consists of a sequence of one or more command
10185 specifications, separated by ",", relating to that interval. The
10186 syntax of a command specification is given by:
10188 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
10191 @var{FLAGS} is optional and specifies the type of events relating to
10192 the time interval which enable sending the specified command, and must
10193 be a non-null sequence of identifier flags separated by "+" or "|" and
10194 enclosed between "[" and "]".
10196 The following flags are recognized:
10199 The command is sent when the current frame timestamp enters the
10200 specified interval. In other words, the command is sent when the
10201 previous frame timestamp was not in the given interval, and the
10205 The command is sent when the current frame timestamp leaves the
10206 specified interval. In other words, the command is sent when the
10207 previous frame timestamp was in the given interval, and the
10211 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
10214 @var{TARGET} specifies the target of the command, usually the name of
10215 the filter class or a specific filter instance name.
10217 @var{COMMAND} specifies the name of the command for the target filter.
10219 @var{ARG} is optional and specifies the optional list of argument for
10220 the given @var{COMMAND}.
10222 Between one interval specification and another, whitespaces, or
10223 sequences of characters starting with @code{#} until the end of line,
10224 are ignored and can be used to annotate comments.
10226 A simplified BNF description of the commands specification syntax
10229 @var{COMMAND_FLAG} ::= "enter" | "leave"
10230 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
10231 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
10232 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
10233 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
10234 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
10237 @subsection Examples
10241 Specify audio tempo change at second 4:
10243 asendcmd=c='4.0 atempo tempo 1.5',atempo
10247 Specify a list of drawtext and hue commands in a file.
10249 # show text in the interval 5-10
10250 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
10251 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
10253 # desaturate the image in the interval 15-20
10254 15.0-20.0 [enter] hue s 0,
10255 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
10257 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
10259 # apply an exponential saturation fade-out effect, starting from time 25
10260 25 [enter] hue s exp(25-t)
10263 A filtergraph allowing to read and process the above command list
10264 stored in a file @file{test.cmd}, can be specified with:
10266 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
10271 @section setpts, asetpts
10273 Change the PTS (presentation timestamp) of the input frames.
10275 @code{setpts} works on video frames, @code{asetpts} on audio frames.
10277 This filter accepts the following options:
10282 The expression which is evaluated for each frame to construct its timestamp.
10286 The expression is evaluated through the eval API and can contain the following
10291 frame rate, only defined for constant frame-rate video
10294 The presentation timestamp in input
10297 The count of the input frame for video or the number of consumed samples,
10298 not including the current frame for audio, starting from 0.
10300 @item NB_CONSUMED_SAMPLES
10301 The number of consumed samples, not including the current frame (only
10304 @item NB_SAMPLES, S
10305 The number of samples in the current frame (only audio)
10307 @item SAMPLE_RATE, SR
10308 The audio sample rate.
10311 The PTS of the first frame.
10314 the time in seconds of the first frame
10317 State whether the current frame is interlaced.
10320 the time in seconds of the current frame
10323 original position in the file of the frame, or undefined if undefined
10324 for the current frame
10327 The previous input PTS.
10330 previous input time in seconds
10333 The previous output PTS.
10336 previous output time in seconds
10339 The wallclock (RTC) time in microseconds.. This is deprecated, use time(0)
10343 The wallclock (RTC) time at the start of the movie in microseconds.
10346 The timebase of the input timestamps.
10350 @subsection Examples
10354 Start counting PTS from zero
10356 setpts=PTS-STARTPTS
10360 Apply fast motion effect:
10366 Apply slow motion effect:
10372 Set fixed rate of 25 frames per second:
10378 Set fixed rate 25 fps with some jitter:
10380 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
10384 Apply an offset of 10 seconds to the input PTS:
10390 Generate timestamps from a "live source" and rebase onto the current timebase:
10392 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
10396 Generate timestamps by counting samples:
10403 @section settb, asettb
10405 Set the timebase to use for the output frames timestamps.
10406 It is mainly useful for testing timebase configuration.
10408 It accepts the following parameters:
10413 The expression which is evaluated into the output timebase.
10417 The value for @option{tb} is an arithmetic expression representing a
10418 rational. The expression can contain the constants "AVTB" (the default
10419 timebase), "intb" (the input timebase) and "sr" (the sample rate,
10420 audio only). Default value is "intb".
10422 @subsection Examples
10426 Set the timebase to 1/25:
10432 Set the timebase to 1/10:
10438 Set the timebase to 1001/1000:
10444 Set the timebase to 2*intb:
10450 Set the default timebase value:
10457 +Convert input audio to a video output representing
10458 frequency spectrum logarithmically (using constant Q transform with
10459 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
10461 The filter accepts the following options:
10465 Specify the transform volume (multiplier). Acceptable value is [1.0, 100.0].
10466 Default value is @code{16.0}.
10469 Specify the transform timeclamp. At low frequency, there is trade-off between
10470 accuracy in time domain and frequency domain. If timeclamp is lower,
10471 event in time domain is represented more accurately (such as fast bass drum),
10472 otherwise event in frequency domain is represented more accurately
10473 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
10476 Specify the transform coeffclamp. If coeffclamp is lower, transform is
10477 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
10478 Default value is @code{1.0}.
10481 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
10482 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
10483 Default value is @code{3.0}.
10486 Specify font file for use with freetype. If not specified, use embedded font.
10489 If set to 1 (the default), the video size is 1920x1080 (full HD),
10490 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
10493 Specify video fps. Default value is @code{25}.
10496 Specify number of transform per frame, so there are fps*count transforms
10497 per second. Note tha audio data rate must be divisible by fps*count.
10498 Default value is @code{6}.
10502 @subsection Examples
10506 Playing audio while showing the spectrum:
10508 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
10512 Same as above, but with frame rate 30 fps:
10514 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
10518 Playing at 960x540 and lower CPU usage:
10520 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
10524 A1 and its harmonics: A1, A2, (near)E3, A3:
10526 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),
10527 asplit[a][out1]; [a] showcqt [out0]'
10531 Same as above, but with more accuracy in frequency domain (and slower):
10533 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),
10534 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
10539 @section showspectrum
10541 Convert input audio to a video output, representing the audio frequency
10544 The filter accepts the following options:
10548 Specify the video size for the output. For the syntax of this option, check
10549 the "Video size" section in the ffmpeg-utils manual. Default value is
10553 Specify if the spectrum should slide along the window. Default value is
10557 Specify display mode.
10559 It accepts the following values:
10562 all channels are displayed in the same row
10564 all channels are displayed in separate rows
10567 Default value is @samp{combined}.
10570 Specify display color mode.
10572 It accepts the following values:
10575 each channel is displayed in a separate color
10577 each channel is is displayed using the same color scheme
10580 Default value is @samp{channel}.
10583 Specify scale used for calculating intensity color values.
10585 It accepts the following values:
10590 square root, default
10597 Default value is @samp{sqrt}.
10600 Set saturation modifier for displayed colors. Negative values provide
10601 alternative color scheme. @code{0} is no saturation at all.
10602 Saturation must be in [-10.0, 10.0] range.
10603 Default value is @code{1}.
10606 Set window function.
10608 It accepts the following values:
10611 No samples pre-processing (do not expect this to be faster)
10620 Default value is @code{hann}.
10623 The usage is very similar to the showwaves filter; see the examples in that
10626 @subsection Examples
10630 Large window with logarithmic color scaling:
10632 showspectrum=s=1280x480:scale=log
10636 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
10638 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10639 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
10645 Convert input audio to a video output, representing the samples waves.
10647 The filter accepts the following options:
10651 Specify the video size for the output. For the syntax of this option, check
10652 the "Video size" section in the ffmpeg-utils manual. Default value
10658 Available values are:
10661 Draw a point for each sample.
10664 Draw a vertical line for each sample.
10667 Default value is @code{point}.
10670 Set the number of samples which are printed on the same column. A
10671 larger value will decrease the frame rate. Must be a positive
10672 integer. This option can be set only if the value for @var{rate}
10673 is not explicitly specified.
10676 Set the (approximate) output frame rate. This is done by setting the
10677 option @var{n}. Default value is "25".
10681 @subsection Examples
10685 Output the input file audio and the corresponding video representation
10688 amovie=a.mp3,asplit[out0],showwaves[out1]
10692 Create a synthetic signal and show it with showwaves, forcing a
10693 frame rate of 30 frames per second:
10695 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
10699 @section split, asplit
10701 Split input into several identical outputs.
10703 @code{asplit} works with audio input, @code{split} with video.
10705 The filter accepts a single parameter which specifies the number of outputs. If
10706 unspecified, it defaults to 2.
10708 @subsection Examples
10712 Create two separate outputs from the same input:
10714 [in] split [out0][out1]
10718 To create 3 or more outputs, you need to specify the number of
10721 [in] asplit=3 [out0][out1][out2]
10725 Create two separate outputs from the same input, one cropped and
10728 [in] split [splitout1][splitout2];
10729 [splitout1] crop=100:100:0:0 [cropout];
10730 [splitout2] pad=200:200:100:100 [padout];
10734 Create 5 copies of the input audio with @command{ffmpeg}:
10736 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
10742 Receive commands sent through a libzmq client, and forward them to
10743 filters in the filtergraph.
10745 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
10746 must be inserted between two video filters, @code{azmq} between two
10749 To enable these filters you need to install the libzmq library and
10750 headers and configure FFmpeg with @code{--enable-libzmq}.
10752 For more information about libzmq see:
10753 @url{http://www.zeromq.org/}
10755 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
10756 receives messages sent through a network interface defined by the
10757 @option{bind_address} option.
10759 The received message must be in the form:
10761 @var{TARGET} @var{COMMAND} [@var{ARG}]
10764 @var{TARGET} specifies the target of the command, usually the name of
10765 the filter class or a specific filter instance name.
10767 @var{COMMAND} specifies the name of the command for the target filter.
10769 @var{ARG} is optional and specifies the optional argument list for the
10770 given @var{COMMAND}.
10772 Upon reception, the message is processed and the corresponding command
10773 is injected into the filtergraph. Depending on the result, the filter
10774 will send a reply to the client, adopting the format:
10776 @var{ERROR_CODE} @var{ERROR_REASON}
10780 @var{MESSAGE} is optional.
10782 @subsection Examples
10784 Look at @file{tools/zmqsend} for an example of a zmq client which can
10785 be used to send commands processed by these filters.
10787 Consider the following filtergraph generated by @command{ffplay}
10789 ffplay -dumpgraph 1 -f lavfi "
10790 color=s=100x100:c=red [l];
10791 color=s=100x100:c=blue [r];
10792 nullsrc=s=200x100, zmq [bg];
10793 [bg][l] overlay [bg+l];
10794 [bg+l][r] overlay=x=100 "
10797 To change the color of the left side of the video, the following
10798 command can be used:
10800 echo Parsed_color_0 c yellow | tools/zmqsend
10803 To change the right side:
10805 echo Parsed_color_1 c pink | tools/zmqsend
10808 @c man end MULTIMEDIA FILTERS
10810 @chapter Multimedia Sources
10811 @c man begin MULTIMEDIA SOURCES
10813 Below is a description of the currently available multimedia sources.
10817 This is the same as @ref{movie} source, except it selects an audio
10823 Read audio and/or video stream(s) from a movie container.
10825 It accepts the following parameters:
10829 The name of the resource to read (not necessarily a file; it can also be a
10830 device or a stream accessed through some protocol).
10832 @item format_name, f
10833 Specifies the format assumed for the movie to read, and can be either
10834 the name of a container or an input device. If not specified, the
10835 format is guessed from @var{movie_name} or by probing.
10837 @item seek_point, sp
10838 Specifies the seek point in seconds. The frames will be output
10839 starting from this seek point. The parameter is evaluated with
10840 @code{av_strtod}, so the numerical value may be suffixed by an IS
10841 postfix. The default value is "0".
10844 Specifies the streams to read. Several streams can be specified,
10845 separated by "+". The source will then have as many outputs, in the
10846 same order. The syntax is explained in the ``Stream specifiers''
10847 section in the ffmpeg manual. Two special names, "dv" and "da" specify
10848 respectively the default (best suited) video and audio stream. Default
10849 is "dv", or "da" if the filter is called as "amovie".
10851 @item stream_index, si
10852 Specifies the index of the video stream to read. If the value is -1,
10853 the most suitable video stream will be automatically selected. The default
10854 value is "-1". Deprecated. If the filter is called "amovie", it will select
10855 audio instead of video.
10858 Specifies how many times to read the stream in sequence.
10859 If the value is less than 1, the stream will be read again and again.
10860 Default value is "1".
10862 Note that when the movie is looped the source timestamps are not
10863 changed, so it will generate non monotonically increasing timestamps.
10866 It allows overlaying a second video on top of the main input of
10867 a filtergraph, as shown in this graph:
10869 input -----------> deltapts0 --> overlay --> output
10872 movie --> scale--> deltapts1 -------+
10874 @subsection Examples
10878 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
10879 on top of the input labelled "in":
10881 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
10882 [in] setpts=PTS-STARTPTS [main];
10883 [main][over] overlay=16:16 [out]
10887 Read from a video4linux2 device, and overlay it on top of the input
10890 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
10891 [in] setpts=PTS-STARTPTS [main];
10892 [main][over] overlay=16:16 [out]
10896 Read the first video stream and the audio stream with id 0x81 from
10897 dvd.vob; the video is connected to the pad named "video" and the audio is
10898 connected to the pad named "audio":
10900 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
10904 @c man end MULTIMEDIA SOURCES