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.
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. Since the filter can be slow, you
3239 may want to reduce this value, at the cost of a less effective filter and the
3240 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 @var{blocksize}-1, which is the best possible setting.
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 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
3260 @var{blocksize}, which is the width and height of the processed blocks.
3262 The default value is @var{3} (8x8) and can be raised to @var{4} for a
3263 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
3264 on the speed processing. Also, a larger block size does not necessarily means a
3268 @subsection Examples
3270 Apply a denoise with a @option{sigma} of @code{4.5}:
3275 The same operation can be achieved using the expression system:
3277 dctdnoiz=e='gte(c, 4.5*3)'
3280 Violent denoise using a block size of @code{16x16}:
3288 Drop duplicated frames at regular intervals.
3290 The filter accepts the following options:
3294 Set the number of frames from which one will be dropped. Setting this to
3295 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3296 Default is @code{5}.
3299 Set the threshold for duplicate detection. If the difference metric for a frame
3300 is less than or equal to this value, then it is declared as duplicate. Default
3304 Set scene change threshold. Default is @code{15}.
3308 Set the size of the x and y-axis blocks used during metric calculations.
3309 Larger blocks give better noise suppression, but also give worse detection of
3310 small movements. Must be a power of two. Default is @code{32}.
3313 Mark main input as a pre-processed input and activate clean source input
3314 stream. This allows the input to be pre-processed with various filters to help
3315 the metrics calculation while keeping the frame selection lossless. When set to
3316 @code{1}, the first stream is for the pre-processed input, and the second
3317 stream is the clean source from where the kept frames are chosen. Default is
3321 Set whether or not chroma is considered in the metric calculations. Default is
3327 Remove judder produced by partially interlaced telecined content.
3329 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3330 source was partially telecined content then the output of @code{pullup,dejudder}
3331 will have a variable frame rate. May change the recorded frame rate of the
3332 container. Aside from that change, this filter will not affect constant frame
3335 The option available in this filter is:
3339 Specify the length of the window over which the judder repeats.
3341 Accepts any integer greater than 1. Useful values are:
3345 If the original was telecined from 24 to 30 fps (Film to NTSC).
3348 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3351 If a mixture of the two.
3354 The default is @samp{4}.
3359 Suppress a TV station logo by a simple interpolation of the surrounding
3360 pixels. Just set a rectangle covering the logo and watch it disappear
3361 (and sometimes something even uglier appear - your mileage may vary).
3363 It accepts the following parameters:
3368 Specify the top left corner coordinates of the logo. They must be
3373 Specify the width and height of the logo to clear. They must be
3377 Specify the thickness of the fuzzy edge of the rectangle (added to
3378 @var{w} and @var{h}). The default value is 4.
3381 When set to 1, a green rectangle is drawn on the screen to simplify
3382 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3383 The default value is 0.
3385 The rectangle is drawn on the outermost pixels which will be (partly)
3386 replaced with interpolated values. The values of the next pixels
3387 immediately outside this rectangle in each direction will be used to
3388 compute the interpolated pixel values inside the rectangle.
3392 @subsection Examples
3396 Set a rectangle covering the area with top left corner coordinates 0,0
3397 and size 100x77, and a band of size 10:
3399 delogo=x=0:y=0:w=100:h=77:band=10
3406 Attempt to fix small changes in horizontal and/or vertical shift. This
3407 filter helps remove camera shake from hand-holding a camera, bumping a
3408 tripod, moving on a vehicle, etc.
3410 The filter accepts the following options:
3418 Specify a rectangular area where to limit the search for motion
3420 If desired the search for motion vectors can be limited to a
3421 rectangular area of the frame defined by its top left corner, width
3422 and height. These parameters have the same meaning as the drawbox
3423 filter which can be used to visualise the position of the bounding
3426 This is useful when simultaneous movement of subjects within the frame
3427 might be confused for camera motion by the motion vector search.
3429 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3430 then the full frame is used. This allows later options to be set
3431 without specifying the bounding box for the motion vector search.
3433 Default - search the whole frame.
3437 Specify the maximum extent of movement in x and y directions in the
3438 range 0-64 pixels. Default 16.
3441 Specify how to generate pixels to fill blanks at the edge of the
3442 frame. Available values are:
3445 Fill zeroes at blank locations
3447 Original image at blank locations
3449 Extruded edge value at blank locations
3451 Mirrored edge at blank locations
3453 Default value is @samp{mirror}.
3456 Specify the blocksize to use for motion search. Range 4-128 pixels,
3460 Specify the contrast threshold for blocks. Only blocks with more than
3461 the specified contrast (difference between darkest and lightest
3462 pixels) will be considered. Range 1-255, default 125.
3465 Specify the search strategy. Available values are:
3468 Set exhaustive search
3470 Set less exhaustive search.
3472 Default value is @samp{exhaustive}.
3475 If set then a detailed log of the motion search is written to the
3479 If set to 1, specify using OpenCL capabilities, only available if
3480 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3486 Draw a colored box on the input image.
3488 It accepts the following parameters:
3493 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3497 The expressions which specify the width and height of the box; if 0 they are interpreted as
3498 the input width and height. It defaults to 0.
3501 Specify the color of the box to write. For the general syntax of this option,
3502 check the "Color" section in the ffmpeg-utils manual. If the special
3503 value @code{invert} is used, the box edge color is the same as the
3504 video with inverted luma.
3507 The expression which sets the thickness of the box edge. Default value is @code{3}.
3509 See below for the list of accepted constants.
3512 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3513 following constants:
3517 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3521 horizontal and vertical chroma subsample values. For example for the
3522 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3526 The input width and height.
3529 The input sample aspect ratio.
3533 The x and y offset coordinates where the box is drawn.
3537 The width and height of the drawn box.
3540 The thickness of the drawn box.
3542 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3543 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3547 @subsection Examples
3551 Draw a black box around the edge of the input image:
3557 Draw a box with color red and an opacity of 50%:
3559 drawbox=10:20:200:60:red@@0.5
3562 The previous example can be specified as:
3564 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3568 Fill the box with pink color:
3570 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3574 Draw a 2-pixel red 2.40:1 mask:
3576 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
3582 Draw a grid on the input image.
3584 It accepts the following parameters:
3589 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3593 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3594 input width and height, respectively, minus @code{thickness}, so image gets
3595 framed. Default to 0.
3598 Specify the color of the grid. For the general syntax of this option,
3599 check the "Color" section in the ffmpeg-utils manual. If the special
3600 value @code{invert} is used, the grid color is the same as the
3601 video with inverted luma.
3604 The expression which sets the thickness of the grid line. Default value is @code{1}.
3606 See below for the list of accepted constants.
3609 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3610 following constants:
3614 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3618 horizontal and vertical chroma subsample values. For example for the
3619 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3623 The input grid cell width and height.
3626 The input sample aspect ratio.
3630 The x and y coordinates of some point of grid intersection (meant to configure offset).
3634 The width and height of the drawn cell.
3637 The thickness of the drawn cell.
3639 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3640 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3644 @subsection Examples
3648 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3650 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3654 Draw a white 3x3 grid with an opacity of 50%:
3656 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3663 Draw a text string or text from a specified file on top of a video, using the
3664 libfreetype library.
3666 To enable compilation of this filter, you need to configure FFmpeg with
3667 @code{--enable-libfreetype}.
3668 To enable default font fallback and the @var{font} option you need to
3669 configure FFmpeg with @code{--enable-libfontconfig}.
3670 To enable the @var{text_shaping} option, you need to configure FFmpeg with
3671 @code{--enable-libfribidi}.
3675 It accepts the following parameters:
3680 Used to draw a box around text using the background color.
3681 The value must be either 1 (enable) or 0 (disable).
3682 The default value of @var{box} is 0.
3685 The color to be used for drawing box around text. For the syntax of this
3686 option, check the "Color" section in the ffmpeg-utils manual.
3688 The default value of @var{boxcolor} is "white".
3691 Set the width of the border to be drawn around the text using @var{bordercolor}.
3692 The default value of @var{borderw} is 0.
3695 Set the color to be used for drawing border around text. For the syntax of this
3696 option, check the "Color" section in the ffmpeg-utils manual.
3698 The default value of @var{bordercolor} is "black".
3701 Select how the @var{text} is expanded. Can be either @code{none},
3702 @code{strftime} (deprecated) or
3703 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3707 If true, check and fix text coords to avoid clipping.
3710 The color to be used for drawing fonts. For the syntax of this option, check
3711 the "Color" section in the ffmpeg-utils manual.
3713 The default value of @var{fontcolor} is "black".
3715 @item fontcolor_expr
3716 String which is expanded the same way as @var{text} to obtain dynamic
3717 @var{fontcolor} value. By default this option has empty value and is not
3718 processed. When this option is set, it overrides @var{fontcolor} option.
3721 The font family to be used for drawing text. By default Sans.
3724 The font file to be used for drawing text. The path must be included.
3725 This parameter is mandatory if the fontconfig support is disabled.
3728 The font size to be used for drawing text.
3729 The default value of @var{fontsize} is 16.
3732 If set to 1, attempt to shape the text (for example, reverse the order of
3733 right-to-left text and join Arabic characters) before drawing it.
3734 Otherwise, just draw the text exactly as given.
3735 By default 1 (if supported).
3738 The flags to be used for loading the fonts.
3740 The flags map the corresponding flags supported by libfreetype, and are
3741 a combination of the following values:
3748 @item vertical_layout
3749 @item force_autohint
3752 @item ignore_global_advance_width
3754 @item ignore_transform
3760 Default value is "default".
3762 For more information consult the documentation for the FT_LOAD_*
3766 The color to be used for drawing a shadow behind the drawn text. For the
3767 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3769 The default value of @var{shadowcolor} is "black".
3773 The x and y offsets for the text shadow position with respect to the
3774 position of the text. They can be either positive or negative
3775 values. The default value for both is "0".
3778 The starting frame number for the n/frame_num variable. The default value
3782 The size in number of spaces to use for rendering the tab.
3786 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3787 format. It can be used with or without text parameter. @var{timecode_rate}
3788 option must be specified.
3790 @item timecode_rate, rate, r
3791 Set the timecode frame rate (timecode only).
3794 The text string to be drawn. The text must be a sequence of UTF-8
3796 This parameter is mandatory if no file is specified with the parameter
3800 A text file containing text to be drawn. The text must be a sequence
3801 of UTF-8 encoded characters.
3803 This parameter is mandatory if no text string is specified with the
3804 parameter @var{text}.
3806 If both @var{text} and @var{textfile} are specified, an error is thrown.
3809 If set to 1, the @var{textfile} will be reloaded before each frame.
3810 Be sure to update it atomically, or it may be read partially, or even fail.
3814 The expressions which specify the offsets where text will be drawn
3815 within the video frame. They are relative to the top/left border of the
3818 The default value of @var{x} and @var{y} is "0".
3820 See below for the list of accepted constants and functions.
3823 The parameters for @var{x} and @var{y} are expressions containing the
3824 following constants and functions:
3828 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3832 horizontal and vertical chroma subsample values. For example for the
3833 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3836 the height of each text line
3844 @item max_glyph_a, ascent
3845 the maximum distance from the baseline to the highest/upper grid
3846 coordinate used to place a glyph outline point, for all the rendered
3848 It is a positive value, due to the grid's orientation with the Y axis
3851 @item max_glyph_d, descent
3852 the maximum distance from the baseline to the lowest grid coordinate
3853 used to place a glyph outline point, for all the rendered glyphs.
3854 This is a negative value, due to the grid's orientation, with the Y axis
3858 maximum glyph height, that is the maximum height for all the glyphs
3859 contained in the rendered text, it is equivalent to @var{ascent} -
3863 maximum glyph width, that is the maximum width for all the glyphs
3864 contained in the rendered text
3867 the number of input frame, starting from 0
3869 @item rand(min, max)
3870 return a random number included between @var{min} and @var{max}
3873 The input sample aspect ratio.
3876 timestamp expressed in seconds, NAN if the input timestamp is unknown
3879 the height of the rendered text
3882 the width of the rendered text
3886 the x and y offset coordinates where the text is drawn.
3888 These parameters allow the @var{x} and @var{y} expressions to refer
3889 each other, so you can for example specify @code{y=x/dar}.
3892 @anchor{drawtext_expansion}
3893 @subsection Text expansion
3895 If @option{expansion} is set to @code{strftime},
3896 the filter recognizes strftime() sequences in the provided text and
3897 expands them accordingly. Check the documentation of strftime(). This
3898 feature is deprecated.
3900 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3902 If @option{expansion} is set to @code{normal} (which is the default),
3903 the following expansion mechanism is used.
3905 The backslash character '\', followed by any character, always expands to
3906 the second character.
3908 Sequence of the form @code{%@{...@}} are expanded. The text between the
3909 braces is a function name, possibly followed by arguments separated by ':'.
3910 If the arguments contain special characters or delimiters (':' or '@}'),
3911 they should be escaped.
3913 Note that they probably must also be escaped as the value for the
3914 @option{text} option in the filter argument string and as the filter
3915 argument in the filtergraph description, and possibly also for the shell,
3916 that makes up to four levels of escaping; using a text file avoids these
3919 The following functions are available:
3924 The expression evaluation result.
3926 It must take one argument specifying the expression to be evaluated,
3927 which accepts the same constants and functions as the @var{x} and
3928 @var{y} values. Note that not all constants should be used, for
3929 example the text size is not known when evaluating the expression, so
3930 the constants @var{text_w} and @var{text_h} will have an undefined
3933 @item expr_int_format, eif
3934 Evaluate the expression's value and output as formatted integer.
3936 First argument is expression to be evaluated, same as for @var{expr} function.
3937 Second argument specifies output format. Allowed values are 'x', 'X', 'd' and
3938 'u', they are treated exactly as in printf function.
3939 Third parameter is optional and sets the number of positions taken by output.
3940 Effectively this allows to add padding with zeros from the left.
3943 The time at which the filter is running, expressed in UTC.
3944 It can accept an argument: a strftime() format string.
3947 The time at which the filter is running, expressed in the local time zone.
3948 It can accept an argument: a strftime() format string.
3951 Frame metadata. It must take one argument specifying metadata key.
3954 The frame number, starting from 0.
3957 A 1 character description of the current picture type.
3960 The timestamp of the current frame.
3961 It can take up to two arguments.
3963 The first argument is the format of the timestamp; it defaults to @code{flt}
3964 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
3965 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
3967 The second argument is an offset added to the timestamp.
3971 @subsection Examples
3975 Draw "Test Text" with font FreeSerif, using the default values for the
3976 optional parameters.
3979 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
3983 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
3984 and y=50 (counting from the top-left corner of the screen), text is
3985 yellow with a red box around it. Both the text and the box have an
3989 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
3990 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
3993 Note that the double quotes are not necessary if spaces are not used
3994 within the parameter list.
3997 Show the text at the center of the video frame:
3999 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
4003 Show a text line sliding from right to left in the last row of the video
4004 frame. The file @file{LONG_LINE} is assumed to contain a single line
4007 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
4011 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
4013 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
4017 Draw a single green letter "g", at the center of the input video.
4018 The glyph baseline is placed at half screen height.
4020 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
4024 Show text for 1 second every 3 seconds:
4026 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
4030 Use fontconfig to set the font. Note that the colons need to be escaped.
4032 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
4036 Print the date of a real-time encoding (see strftime(3)):
4038 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
4042 Shwo text fading in and out (appearing/disappearing):
4045 DS=1.0 # display start
4046 DE=10.0 # display end
4047 FID=1.5 # fade in duration
4048 FOD=5 # fade out duration
4049 ffplay -f lavfi "color,drawtext=text=TEST:fontsize=50:fontfile=FreeSerif.ttf:fontcolor_expr=ff0000%@{eif\\\\: clip(255*(1*between(t\\, $DS + $FID\\, $DE - $FOD) + ((t - $DS)/$FID)*between(t\\, $DS\\, $DS + $FID) + (-(t - $DE)/$FOD)*between(t\\, $DE - $FOD\\, $DE) )\\, 0\\, 255) \\\\: x\\\\: 2 @}"
4054 For more information about libfreetype, check:
4055 @url{http://www.freetype.org/}.
4057 For more information about fontconfig, check:
4058 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
4060 For more information about libfribidi, check:
4061 @url{http://fribidi.org/}.
4065 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
4067 The filter accepts the following options:
4072 Set low and high threshold values used by the Canny thresholding
4075 The high threshold selects the "strong" edge pixels, which are then
4076 connected through 8-connectivity with the "weak" edge pixels selected
4077 by the low threshold.
4079 @var{low} and @var{high} threshold values must be chosen in the range
4080 [0,1], and @var{low} should be lesser or equal to @var{high}.
4082 Default value for @var{low} is @code{20/255}, and default value for @var{high}
4086 Define the drawing mode.
4090 Draw white/gray wires on black background.
4093 Mix the colors to create a paint/cartoon effect.
4096 Default value is @var{wires}.
4099 @subsection Examples
4103 Standard edge detection with custom values for the hysteresis thresholding:
4105 edgedetect=low=0.1:high=0.4
4109 Painting effect without thresholding:
4111 edgedetect=mode=colormix:high=0
4115 @section extractplanes
4117 Extract color channel components from input video stream into
4118 separate grayscale video streams.
4120 The filter accepts the following option:
4124 Set plane(s) to extract.
4126 Available values for planes are:
4137 Choosing planes not available in the input will result in an error.
4138 That means you cannot select @code{r}, @code{g}, @code{b} planes
4139 with @code{y}, @code{u}, @code{v} planes at same time.
4142 @subsection Examples
4146 Extract luma, u and v color channel component from input video frame
4147 into 3 grayscale outputs:
4149 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
4155 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4157 For each input image, the filter will compute the optimal mapping from
4158 the input to the output given the codebook length, that is the number
4159 of distinct output colors.
4161 This filter accepts the following options.
4164 @item codebook_length, l
4165 Set codebook length. The value must be a positive integer, and
4166 represents the number of distinct output colors. Default value is 256.
4169 Set the maximum number of iterations to apply for computing the optimal
4170 mapping. The higher the value the better the result and the higher the
4171 computation time. Default value is 1.
4174 Set a random seed, must be an integer included between 0 and
4175 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4176 will try to use a good random seed on a best effort basis.
4181 Apply a fade-in/out effect to the input video.
4183 It accepts the following parameters:
4187 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4189 Default is @code{in}.
4191 @item start_frame, s
4192 Specify the number of the frame to start applying the fade
4193 effect at. Default is 0.
4196 The number of frames that the fade effect lasts. At the end of the
4197 fade-in effect, the output video will have the same intensity as the input video.
4198 At the end of the fade-out transition, the output video will be filled with the
4199 selected @option{color}.
4203 If set to 1, fade only alpha channel, if one exists on the input.
4206 @item start_time, st
4207 Specify the timestamp (in seconds) of the frame to start to apply the fade
4208 effect. If both start_frame and start_time are specified, the fade will start at
4209 whichever comes last. Default is 0.
4212 The number of seconds for which the fade effect has to last. At the end of the
4213 fade-in effect the output video will have the same intensity as the input video,
4214 at the end of the fade-out transition the output video will be filled with the
4215 selected @option{color}.
4216 If both duration and nb_frames are specified, duration is used. Default is 0.
4219 Specify the color of the fade. Default is "black".
4222 @subsection Examples
4226 Fade in the first 30 frames of video:
4231 The command above is equivalent to:
4237 Fade out the last 45 frames of a 200-frame video:
4240 fade=type=out:start_frame=155:nb_frames=45
4244 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4246 fade=in:0:25, fade=out:975:25
4250 Make the first 5 frames yellow, then fade in from frame 5-24:
4252 fade=in:5:20:color=yellow
4256 Fade in alpha over first 25 frames of video:
4258 fade=in:0:25:alpha=1
4262 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4264 fade=t=in:st=5.5:d=0.5
4271 Extract a single field from an interlaced image using stride
4272 arithmetic to avoid wasting CPU time. The output frames are marked as
4275 The filter accepts the following options:
4279 Specify whether to extract the top (if the value is @code{0} or
4280 @code{top}) or the bottom field (if the value is @code{1} or
4286 Field matching filter for inverse telecine. It is meant to reconstruct the
4287 progressive frames from a telecined stream. The filter does not drop duplicated
4288 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4289 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4291 The separation of the field matching and the decimation is notably motivated by
4292 the possibility of inserting a de-interlacing filter fallback between the two.
4293 If the source has mixed telecined and real interlaced content,
4294 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4295 But these remaining combed frames will be marked as interlaced, and thus can be
4296 de-interlaced by a later filter such as @ref{yadif} before decimation.
4298 In addition to the various configuration options, @code{fieldmatch} can take an
4299 optional second stream, activated through the @option{ppsrc} option. If
4300 enabled, the frames reconstruction will be based on the fields and frames from
4301 this second stream. This allows the first input to be pre-processed in order to
4302 help the various algorithms of the filter, while keeping the output lossless
4303 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4304 or brightness/contrast adjustments can help.
4306 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4307 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4308 which @code{fieldmatch} is based on. While the semantic and usage are very
4309 close, some behaviour and options names can differ.
4311 The filter accepts the following options:
4315 Specify the assumed field order of the input stream. Available values are:
4319 Auto detect parity (use FFmpeg's internal parity value).
4321 Assume bottom field first.
4323 Assume top field first.
4326 Note that it is sometimes recommended not to trust the parity announced by the
4329 Default value is @var{auto}.
4332 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4333 sense that it won't risk creating jerkiness due to duplicate frames when
4334 possible, but if there are bad edits or blended fields it will end up
4335 outputting combed frames when a good match might actually exist. On the other
4336 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4337 but will almost always find a good frame if there is one. The other values are
4338 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4339 jerkiness and creating duplicate frames versus finding good matches in sections
4340 with bad edits, orphaned fields, blended fields, etc.
4342 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4344 Available values are:
4348 2-way matching (p/c)
4350 2-way matching, and trying 3rd match if still combed (p/c + n)
4352 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4354 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4355 still combed (p/c + n + u/b)
4357 3-way matching (p/c/n)
4359 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4360 detected as combed (p/c/n + u/b)
4363 The parenthesis at the end indicate the matches that would be used for that
4364 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4367 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4370 Default value is @var{pc_n}.
4373 Mark the main input stream as a pre-processed input, and enable the secondary
4374 input stream as the clean source to pick the fields from. See the filter
4375 introduction for more details. It is similar to the @option{clip2} feature from
4378 Default value is @code{0} (disabled).
4381 Set the field to match from. It is recommended to set this to the same value as
4382 @option{order} unless you experience matching failures with that setting. In
4383 certain circumstances changing the field that is used to match from can have a
4384 large impact on matching performance. Available values are:
4388 Automatic (same value as @option{order}).
4390 Match from the bottom field.
4392 Match from the top field.
4395 Default value is @var{auto}.
4398 Set whether or not chroma is included during the match comparisons. In most
4399 cases it is recommended to leave this enabled. You should set this to @code{0}
4400 only if your clip has bad chroma problems such as heavy rainbowing or other
4401 artifacts. Setting this to @code{0} could also be used to speed things up at
4402 the cost of some accuracy.
4404 Default value is @code{1}.
4408 These define an exclusion band which excludes the lines between @option{y0} and
4409 @option{y1} from being included in the field matching decision. An exclusion
4410 band can be used to ignore subtitles, a logo, or other things that may
4411 interfere with the matching. @option{y0} sets the starting scan line and
4412 @option{y1} sets the ending line; all lines in between @option{y0} and
4413 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4414 @option{y0} and @option{y1} to the same value will disable the feature.
4415 @option{y0} and @option{y1} defaults to @code{0}.
4418 Set the scene change detection threshold as a percentage of maximum change on
4419 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4420 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4421 @option{scthresh} is @code{[0.0, 100.0]}.
4423 Default value is @code{12.0}.
4426 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4427 account the combed scores of matches when deciding what match to use as the
4428 final match. Available values are:
4432 No final matching based on combed scores.
4434 Combed scores are only used when a scene change is detected.
4436 Use combed scores all the time.
4439 Default is @var{sc}.
4442 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4443 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4444 Available values are:
4448 No forced calculation.
4450 Force p/c/n calculations.
4452 Force p/c/n/u/b calculations.
4455 Default value is @var{none}.
4458 This is the area combing threshold used for combed frame detection. This
4459 essentially controls how "strong" or "visible" combing must be to be detected.
4460 Larger values mean combing must be more visible and smaller values mean combing
4461 can be less visible or strong and still be detected. Valid settings are from
4462 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4463 be detected as combed). This is basically a pixel difference value. A good
4464 range is @code{[8, 12]}.
4466 Default value is @code{9}.
4469 Sets whether or not chroma is considered in the combed frame decision. Only
4470 disable this if your source has chroma problems (rainbowing, etc.) that are
4471 causing problems for the combed frame detection with chroma enabled. Actually,
4472 using @option{chroma}=@var{0} is usually more reliable, except for the case
4473 where there is chroma only combing in the source.
4475 Default value is @code{0}.
4479 Respectively set the x-axis and y-axis size of the window used during combed
4480 frame detection. This has to do with the size of the area in which
4481 @option{combpel} pixels are required to be detected as combed for a frame to be
4482 declared combed. See the @option{combpel} parameter description for more info.
4483 Possible values are any number that is a power of 2 starting at 4 and going up
4486 Default value is @code{16}.
4489 The number of combed pixels inside any of the @option{blocky} by
4490 @option{blockx} size blocks on the frame for the frame to be detected as
4491 combed. While @option{cthresh} controls how "visible" the combing must be, this
4492 setting controls "how much" combing there must be in any localized area (a
4493 window defined by the @option{blockx} and @option{blocky} settings) on the
4494 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4495 which point no frames will ever be detected as combed). This setting is known
4496 as @option{MI} in TFM/VFM vocabulary.
4498 Default value is @code{80}.
4501 @anchor{p/c/n/u/b meaning}
4502 @subsection p/c/n/u/b meaning
4504 @subsubsection p/c/n
4506 We assume the following telecined stream:
4509 Top fields: 1 2 2 3 4
4510 Bottom fields: 1 2 3 4 4
4513 The numbers correspond to the progressive frame the fields relate to. Here, the
4514 first two frames are progressive, the 3rd and 4th are combed, and so on.
4516 When @code{fieldmatch} is configured to run a matching from bottom
4517 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4522 B 1 2 3 4 4 <-- matching reference
4531 As a result of the field matching, we can see that some frames get duplicated.
4532 To perform a complete inverse telecine, you need to rely on a decimation filter
4533 after this operation. See for instance the @ref{decimate} filter.
4535 The same operation now matching from top fields (@option{field}=@var{top})
4540 T 1 2 2 3 4 <-- matching reference
4550 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4551 basically, they refer to the frame and field of the opposite parity:
4554 @item @var{p} matches the field of the opposite parity in the previous frame
4555 @item @var{c} matches the field of the opposite parity in the current frame
4556 @item @var{n} matches the field of the opposite parity in the next frame
4561 The @var{u} and @var{b} matching are a bit special in the sense that they match
4562 from the opposite parity flag. In the following examples, we assume that we are
4563 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4564 'x' is placed above and below each matched fields.
4566 With bottom matching (@option{field}=@var{bottom}):
4571 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4572 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4580 With top matching (@option{field}=@var{top}):
4585 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4586 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4594 @subsection Examples
4596 Simple IVTC of a top field first telecined stream:
4598 fieldmatch=order=tff:combmatch=none, decimate
4601 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4603 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4608 Transform the field order of the input video.
4610 It accepts the following parameters:
4615 The output field order. Valid values are @var{tff} for top field first or @var{bff}
4616 for bottom field first.
4619 The default value is @samp{tff}.
4621 The transformation is done by shifting the picture content up or down
4622 by one line, and filling the remaining line with appropriate picture content.
4623 This method is consistent with most broadcast field order converters.
4625 If the input video is not flagged as being interlaced, or it is already
4626 flagged as being of the required output field order, then this filter does
4627 not alter the incoming video.
4629 It is very useful when converting to or from PAL DV material,
4630 which is bottom field first.
4634 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4639 Buffer input images and send them when they are requested.
4641 It is mainly useful when auto-inserted by the libavfilter
4644 It does not take parameters.
4649 Convert the input video to one of the specified pixel formats.
4650 Libavfilter will try to pick one that is suitable as input to
4653 It accepts the following parameters:
4657 A '|'-separated list of pixel format names, such as
4658 "pix_fmts=yuv420p|monow|rgb24".
4662 @subsection Examples
4666 Convert the input video to the @var{yuv420p} format
4668 format=pix_fmts=yuv420p
4671 Convert the input video to any of the formats in the list
4673 format=pix_fmts=yuv420p|yuv444p|yuv410p
4680 Convert the video to specified constant frame rate by duplicating or dropping
4681 frames as necessary.
4683 It accepts the following parameters:
4687 The desired output frame rate. The default is @code{25}.
4692 Possible values are:
4695 zero round towards 0
4699 round towards -infinity
4701 round towards +infinity
4705 The default is @code{near}.
4708 Assume the first PTS should be the given value, in seconds. This allows for
4709 padding/trimming at the start of stream. By default, no assumption is made
4710 about the first frame's expected PTS, so no padding or trimming is done.
4711 For example, this could be set to 0 to pad the beginning with duplicates of
4712 the first frame if a video stream starts after the audio stream or to trim any
4713 frames with a negative PTS.
4717 Alternatively, the options can be specified as a flat string:
4718 @var{fps}[:@var{round}].
4720 See also the @ref{setpts} filter.
4722 @subsection Examples
4726 A typical usage in order to set the fps to 25:
4732 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4734 fps=fps=film:round=near
4740 Pack two different video streams into a stereoscopic video, setting proper
4741 metadata on supported codecs. The two views should have the same size and
4742 framerate and processing will stop when the shorter video ends. Please note
4743 that you may conveniently adjust view properties with the @ref{scale} and
4746 It accepts the following parameters:
4750 The desired packing format. Supported values are:
4755 The views are next to each other (default).
4758 The views are on top of each other.
4761 The views are packed by line.
4764 The views are packed by column.
4767 The views are temporally interleaved.
4776 # Convert left and right views into a frame-sequential video
4777 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
4779 # Convert views into a side-by-side video with the same output resolution as the input
4780 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
4785 Select one frame every N-th frame.
4787 This filter accepts the following option:
4790 Select frame after every @code{step} frames.
4791 Allowed values are positive integers higher than 0. Default value is @code{1}.
4797 Apply a frei0r effect to the input video.
4799 To enable the compilation of this filter, you need to install the frei0r
4800 header and configure FFmpeg with @code{--enable-frei0r}.
4802 It accepts the following parameters:
4807 The name of the frei0r effect to load. If the environment variable
4808 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
4809 directories specified by the colon-separated list in @env{FREIOR_PATH}.
4810 Otherwise, the standard frei0r paths are searched, in this order:
4811 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
4812 @file{/usr/lib/frei0r-1/}.
4815 A '|'-separated list of parameters to pass to the frei0r effect.
4819 A frei0r effect parameter can be a boolean (its value is either
4820 "y" or "n"), a double, a color (specified as
4821 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
4822 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
4823 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
4824 @var{X} and @var{Y} are floating point numbers) and/or a string.
4826 The number and types of parameters depend on the loaded effect. If an
4827 effect parameter is not specified, the default value is set.
4829 @subsection Examples
4833 Apply the distort0r effect, setting the first two double parameters:
4835 frei0r=filter_name=distort0r:filter_params=0.5|0.01
4839 Apply the colordistance effect, taking a color as the first parameter:
4841 frei0r=colordistance:0.2/0.3/0.4
4842 frei0r=colordistance:violet
4843 frei0r=colordistance:0x112233
4847 Apply the perspective effect, specifying the top left and top right image
4850 frei0r=perspective:0.2/0.2|0.8/0.2
4854 For more information, see
4855 @url{http://frei0r.dyne.org}
4859 The filter accepts the following options:
4863 Set the luminance expression.
4865 Set the chrominance blue expression.
4867 Set the chrominance red expression.
4869 Set the alpha expression.
4871 Set the red expression.
4873 Set the green expression.
4875 Set the blue expression.
4878 The colorspace is selected according to the specified options. If one
4879 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4880 options is specified, the filter will automatically select a YCbCr
4881 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4882 @option{blue_expr} options is specified, it will select an RGB
4885 If one of the chrominance expression is not defined, it falls back on the other
4886 one. If no alpha expression is specified it will evaluate to opaque value.
4887 If none of chrominance expressions are specified, they will evaluate
4888 to the luminance expression.
4890 The expressions can use the following variables and functions:
4894 The sequential number of the filtered frame, starting from @code{0}.
4898 The coordinates of the current sample.
4902 The width and height of the image.
4906 Width and height scale depending on the currently filtered plane. It is the
4907 ratio between the corresponding luma plane number of pixels and the current
4908 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4909 @code{0.5,0.5} for chroma planes.
4912 Time of the current frame, expressed in seconds.
4915 Return the value of the pixel at location (@var{x},@var{y}) of the current
4919 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
4923 Return the value of the pixel at location (@var{x},@var{y}) of the
4924 blue-difference chroma plane. Return 0 if there is no such plane.
4927 Return the value of the pixel at location (@var{x},@var{y}) of the
4928 red-difference chroma plane. Return 0 if there is no such plane.
4933 Return the value of the pixel at location (@var{x},@var{y}) of the
4934 red/green/blue component. Return 0 if there is no such component.
4937 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
4938 plane. Return 0 if there is no such plane.
4941 For functions, if @var{x} and @var{y} are outside the area, the value will be
4942 automatically clipped to the closer edge.
4944 @subsection Examples
4948 Flip the image horizontally:
4954 Generate a bidimensional sine wave, with angle @code{PI/3} and a
4955 wavelength of 100 pixels:
4957 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
4961 Generate a fancy enigmatic moving light:
4963 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
4967 Generate a quick emboss effect:
4969 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
4973 Modify RGB components depending on pixel position:
4975 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
4981 Fix the banding artifacts that are sometimes introduced into nearly flat
4982 regions by truncation to 8bit color depth.
4983 Interpolate the gradients that should go where the bands are, and
4986 It is designed for playback only. Do not use it prior to
4987 lossy compression, because compression tends to lose the dither and
4988 bring back the bands.
4990 It accepts the following parameters:
4995 The maximum amount by which the filter will change any one pixel. This is also
4996 the threshold for detecting nearly flat regions. Acceptable values range from
4997 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
5001 The neighborhood to fit the gradient to. A larger radius makes for smoother
5002 gradients, but also prevents the filter from modifying the pixels near detailed
5003 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
5004 values will be clipped to the valid range.
5008 Alternatively, the options can be specified as a flat string:
5009 @var{strength}[:@var{radius}]
5011 @subsection Examples
5015 Apply the filter with a @code{3.5} strength and radius of @code{8}:
5021 Specify radius, omitting the strength (which will fall-back to the default
5032 Apply a Hald CLUT to a video stream.
5034 First input is the video stream to process, and second one is the Hald CLUT.
5035 The Hald CLUT input can be a simple picture or a complete video stream.
5037 The filter accepts the following options:
5041 Force termination when the shortest input terminates. Default is @code{0}.
5043 Continue applying the last CLUT after the end of the stream. A value of
5044 @code{0} disable the filter after the last frame of the CLUT is reached.
5045 Default is @code{1}.
5048 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
5049 filters share the same internals).
5051 More information about the Hald CLUT can be found on Eskil Steenberg's website
5052 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
5054 @subsection Workflow examples
5056 @subsubsection Hald CLUT video stream
5058 Generate an identity Hald CLUT stream altered with various effects:
5060 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
5063 Note: make sure you use a lossless codec.
5065 Then use it with @code{haldclut} to apply it on some random stream:
5067 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
5070 The Hald CLUT will be applied to the 10 first seconds (duration of
5071 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
5072 to the remaining frames of the @code{mandelbrot} stream.
5074 @subsubsection Hald CLUT with preview
5076 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
5077 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
5078 biggest possible square starting at the top left of the picture. The remaining
5079 padding pixels (bottom or right) will be ignored. This area can be used to add
5080 a preview of the Hald CLUT.
5082 Typically, the following generated Hald CLUT will be supported by the
5083 @code{haldclut} filter:
5086 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
5087 pad=iw+320 [padded_clut];
5088 smptebars=s=320x256, split [a][b];
5089 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
5090 [main][b] overlay=W-320" -frames:v 1 clut.png
5093 It contains the original and a preview of the effect of the CLUT: SMPTE color
5094 bars are displayed on the right-top, and below the same color bars processed by
5097 Then, the effect of this Hald CLUT can be visualized with:
5099 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
5104 Flip the input video horizontally.
5106 For example, to horizontally flip the input video with @command{ffmpeg}:
5108 ffmpeg -i in.avi -vf "hflip" out.avi
5112 This filter applies a global color histogram equalization on a
5115 It can be used to correct video that has a compressed range of pixel
5116 intensities. The filter redistributes the pixel intensities to
5117 equalize their distribution across the intensity range. It may be
5118 viewed as an "automatically adjusting contrast filter". This filter is
5119 useful only for correcting degraded or poorly captured source
5122 The filter accepts the following options:
5126 Determine the amount of equalization to be applied. As the strength
5127 is reduced, the distribution of pixel intensities more-and-more
5128 approaches that of the input frame. The value must be a float number
5129 in the range [0,1] and defaults to 0.200.
5132 Set the maximum intensity that can generated and scale the output
5133 values appropriately. The strength should be set as desired and then
5134 the intensity can be limited if needed to avoid washing-out. The value
5135 must be a float number in the range [0,1] and defaults to 0.210.
5138 Set the antibanding level. If enabled the filter will randomly vary
5139 the luminance of output pixels by a small amount to avoid banding of
5140 the histogram. Possible values are @code{none}, @code{weak} or
5141 @code{strong}. It defaults to @code{none}.
5146 Compute and draw a color distribution histogram for the input video.
5148 The computed histogram is a representation of the color component
5149 distribution in an image.
5151 The filter accepts the following options:
5157 It accepts the following values:
5160 Standard histogram that displays the color components distribution in an
5161 image. Displays color graph for each color component. Shows distribution of
5162 the Y, U, V, A or R, G, B components, depending on input format, in the
5163 current frame. Below each graph a color component scale meter is shown.
5166 Displays chroma values (U/V color placement) in a two dimensional
5167 graph (which is called a vectorscope). The brighter a pixel in the
5168 vectorscope, the more pixels of the input frame correspond to that pixel
5169 (i.e., more pixels have this chroma value). The V component is displayed on
5170 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5171 side being V = 255. The U component is displayed on the vertical (Y) axis,
5172 with the top representing U = 0 and the bottom representing U = 255.
5174 The position of a white pixel in the graph corresponds to the chroma value of
5175 a pixel of the input clip. The graph can therefore be used to read the hue
5176 (color flavor) and the saturation (the dominance of the hue in the color). As
5177 the hue of a color changes, it moves around the square. At the center of the
5178 square the saturation is zero, which means that the corresponding pixel has no
5179 color. If the amount of a specific color is increased (while leaving the other
5180 colors unchanged) the saturation increases, and the indicator moves towards
5181 the edge of the square.
5184 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5188 Per row/column color component graph. In row mode, the graph on the left side
5189 represents color component value 0 and the right side represents value = 255.
5190 In column mode, the top side represents color component value = 0 and bottom
5191 side represents value = 255.
5193 Default value is @code{levels}.
5196 Set height of level in @code{levels}. Default value is @code{200}.
5197 Allowed range is [50, 2048].
5200 Set height of color scale in @code{levels}. Default value is @code{12}.
5201 Allowed range is [0, 40].
5204 Set step for @code{waveform} mode. Smaller values are useful to find out how
5205 many values of the same luminance are distributed across input rows/columns.
5206 Default value is @code{10}. Allowed range is [1, 255].
5209 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5210 Default is @code{row}.
5212 @item waveform_mirror
5213 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5214 means mirrored. In mirrored mode, higher values will be represented on the left
5215 side for @code{row} mode and at the top for @code{column} mode. Default is
5216 @code{0} (unmirrored).
5219 Set display mode for @code{waveform} and @code{levels}.
5220 It accepts the following values:
5223 Display separate graph for the color components side by side in
5224 @code{row} waveform mode or one below the other in @code{column} waveform mode
5225 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5226 per color component graphs are placed below each other.
5228 Using this display mode in @code{waveform} histogram mode makes it easy to
5229 spot color casts in the highlights and shadows of an image, by comparing the
5230 contours of the top and the bottom graphs of each waveform. Since whites,
5231 grays, and blacks are characterized by exactly equal amounts of red, green,
5232 and blue, neutral areas of the picture should display three waveforms of
5233 roughly equal width/height. If not, the correction is easy to perform by
5234 making level adjustments the three waveforms.
5237 Presents information identical to that in the @code{parade}, except
5238 that the graphs representing color components are superimposed directly
5241 This display mode in @code{waveform} histogram mode makes it easier to spot
5242 relative differences or similarities in overlapping areas of the color
5243 components that are supposed to be identical, such as neutral whites, grays,
5246 Default is @code{parade}.
5249 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5250 Default is @code{linear}.
5253 @subsection Examples
5258 Calculate and draw histogram:
5260 ffplay -i input -vf histogram
5268 This is a high precision/quality 3d denoise filter. It aims to reduce
5269 image noise, producing smooth images and making still images really
5270 still. It should enhance compressibility.
5272 It accepts the following optional parameters:
5276 A non-negative floating point number which specifies spatial luma strength.
5279 @item chroma_spatial
5280 A non-negative floating point number which specifies spatial chroma strength.
5281 It defaults to 3.0*@var{luma_spatial}/4.0.
5284 A floating point number which specifies luma temporal strength. It defaults to
5285 6.0*@var{luma_spatial}/4.0.
5288 A floating point number which specifies chroma temporal strength. It defaults to
5289 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5294 Apply a high-quality magnification filter designed for pixel art. This filter
5295 was originally created by Maxim Stepin.
5297 It accepts the following option:
5301 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
5302 @code{hq3x} and @code{4} for @code{hq4x}.
5303 Default is @code{3}.
5308 Modify the hue and/or the saturation of the input.
5310 It accepts the following parameters:
5314 Specify the hue angle as a number of degrees. It accepts an expression,
5315 and defaults to "0".
5318 Specify the saturation in the [-10,10] range. It accepts an expression and
5322 Specify the hue angle as a number of radians. It accepts an
5323 expression, and defaults to "0".
5326 Specify the brightness in the [-10,10] range. It accepts an expression and
5330 @option{h} and @option{H} are mutually exclusive, and can't be
5331 specified at the same time.
5333 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5334 expressions containing the following constants:
5338 frame count of the input frame starting from 0
5341 presentation timestamp of the input frame expressed in time base units
5344 frame rate of the input video, NAN if the input frame rate is unknown
5347 timestamp expressed in seconds, NAN if the input timestamp is unknown
5350 time base of the input video
5353 @subsection Examples
5357 Set the hue to 90 degrees and the saturation to 1.0:
5363 Same command but expressing the hue in radians:
5369 Rotate hue and make the saturation swing between 0
5370 and 2 over a period of 1 second:
5372 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5376 Apply a 3 seconds saturation fade-in effect starting at 0:
5381 The general fade-in expression can be written as:
5383 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5387 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5389 hue="s=max(0\, min(1\, (8-t)/3))"
5392 The general fade-out expression can be written as:
5394 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5399 @subsection Commands
5401 This filter supports the following commands:
5407 Modify the hue and/or the saturation and/or brightness of the input video.
5408 The command accepts the same syntax of the corresponding option.
5410 If the specified expression is not valid, it is kept at its current
5416 Detect video interlacing type.
5418 This filter tries to detect if the input is interlaced or progressive,
5419 top or bottom field first.
5421 The filter accepts the following options:
5425 Set interlacing threshold.
5427 Set progressive threshold.
5432 Deinterleave or interleave fields.
5434 This filter allows one to process interlaced images fields without
5435 deinterlacing them. Deinterleaving splits the input frame into 2
5436 fields (so called half pictures). Odd lines are moved to the top
5437 half of the output image, even lines to the bottom half.
5438 You can process (filter) them independently and then re-interleave them.
5440 The filter accepts the following options:
5444 @item chroma_mode, c
5446 Available values for @var{luma_mode}, @var{chroma_mode} and
5447 @var{alpha_mode} are:
5453 @item deinterleave, d
5454 Deinterleave fields, placing one above the other.
5457 Interleave fields. Reverse the effect of deinterleaving.
5459 Default value is @code{none}.
5462 @item chroma_swap, cs
5463 @item alpha_swap, as
5464 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5469 Simple interlacing filter from progressive contents. This interleaves upper (or
5470 lower) lines from odd frames with lower (or upper) lines from even frames,
5471 halving the frame rate and preserving image height.
5474 Original Original New Frame
5475 Frame 'j' Frame 'j+1' (tff)
5476 ========== =========== ==================
5477 Line 0 --------------------> Frame 'j' Line 0
5478 Line 1 Line 1 ----> Frame 'j+1' Line 1
5479 Line 2 ---------------------> Frame 'j' Line 2
5480 Line 3 Line 3 ----> Frame 'j+1' Line 3
5482 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5485 It accepts the following optional parameters:
5489 This determines whether the interlaced frame is taken from the even
5490 (tff - default) or odd (bff) lines of the progressive frame.
5493 Enable (default) or disable the vertical lowpass filter to avoid twitter
5494 interlacing and reduce moire patterns.
5499 Deinterlace input video by applying Donald Graft's adaptive kernel
5500 deinterling. Work on interlaced parts of a video to produce
5503 The description of the accepted parameters follows.
5507 Set the threshold which affects the filter's tolerance when
5508 determining if a pixel line must be processed. It must be an integer
5509 in the range [0,255] and defaults to 10. A value of 0 will result in
5510 applying the process on every pixels.
5513 Paint pixels exceeding the threshold value to white if set to 1.
5517 Set the fields order. Swap fields if set to 1, leave fields alone if
5521 Enable additional sharpening if set to 1. Default is 0.
5524 Enable twoway sharpening if set to 1. Default is 0.
5527 @subsection Examples
5531 Apply default values:
5533 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5537 Enable additional sharpening:
5543 Paint processed pixels in white:
5552 Apply a 3D LUT to an input video.
5554 The filter accepts the following options:
5558 Set the 3D LUT file name.
5560 Currently supported formats:
5572 Select interpolation mode.
5574 Available values are:
5578 Use values from the nearest defined point.
5580 Interpolate values using the 8 points defining a cube.
5582 Interpolate values using a tetrahedron.
5586 @section lut, lutrgb, lutyuv
5588 Compute a look-up table for binding each pixel component input value
5589 to an output value, and apply it to the input video.
5591 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5592 to an RGB input video.
5594 These filters accept the following parameters:
5597 set first pixel component expression
5599 set second pixel component expression
5601 set third pixel component expression
5603 set fourth pixel component expression, corresponds to the alpha component
5606 set red component expression
5608 set green component expression
5610 set blue component expression
5612 alpha component expression
5615 set Y/luminance component expression
5617 set U/Cb component expression
5619 set V/Cr component expression
5622 Each of them specifies the expression to use for computing the lookup table for
5623 the corresponding pixel component values.
5625 The exact component associated to each of the @var{c*} options depends on the
5628 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5629 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5631 The expressions can contain the following constants and functions:
5636 The input width and height.
5639 The input value for the pixel component.
5642 The input value, clipped to the @var{minval}-@var{maxval} range.
5645 The maximum value for the pixel component.
5648 The minimum value for the pixel component.
5651 The negated value for the pixel component value, clipped to the
5652 @var{minval}-@var{maxval} range; it corresponds to the expression
5653 "maxval-clipval+minval".
5656 The computed value in @var{val}, clipped to the
5657 @var{minval}-@var{maxval} range.
5659 @item gammaval(gamma)
5660 The computed gamma correction value of the pixel component value,
5661 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
5663 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
5667 All expressions default to "val".
5669 @subsection Examples
5675 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
5676 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
5679 The above is the same as:
5681 lutrgb="r=negval:g=negval:b=negval"
5682 lutyuv="y=negval:u=negval:v=negval"
5692 Remove chroma components, turning the video into a graytone image:
5694 lutyuv="u=128:v=128"
5698 Apply a luma burning effect:
5704 Remove green and blue components:
5710 Set a constant alpha channel value on input:
5712 format=rgba,lutrgb=a="maxval-minval/2"
5716 Correct luminance gamma by a factor of 0.5:
5718 lutyuv=y=gammaval(0.5)
5722 Discard least significant bits of luma:
5724 lutyuv=y='bitand(val, 128+64+32)'
5728 @section mergeplanes
5730 Merge color channel components from several video streams.
5732 The filter accepts up to 4 input streams, and merge selected input
5733 planes to the output video.
5735 This filter accepts the following options:
5738 Set input to output plane mapping. Default is @code{0}.
5740 The mappings is specified as a bitmap. It should be specified as a
5741 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
5742 mapping for the first plane of the output stream. 'A' sets the number of
5743 the input stream to use (from 0 to 3), and 'a' the plane number of the
5744 corresponding input to use (from 0 to 3). The rest of the mappings is
5745 similar, 'Bb' describes the mapping for the output stream second
5746 plane, 'Cc' describes the mapping for the output stream third plane and
5747 'Dd' describes the mapping for the output stream fourth plane.
5750 Set output pixel format. Default is @code{yuva444p}.
5753 @subsection Examples
5757 Merge three gray video streams of same width and height into single video stream:
5759 [a0][a1][a2]mergeplanes=0x001020:yuv444p
5763 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
5765 [a0][a1]mergeplanes=0x00010210:yuva444p
5769 Swap Y and A plane in yuva444p stream:
5771 format=yuva444p,mergeplanes=0x03010200:yuva444p
5775 Swap U and V plane in yuv420p stream:
5777 format=yuv420p,mergeplanes=0x000201:yuv420p
5781 Cast a rgb24 clip to yuv444p:
5783 format=rgb24,mergeplanes=0x000102:yuv444p
5789 Apply motion-compensation deinterlacing.
5791 It needs one field per frame as input and must thus be used together
5792 with yadif=1/3 or equivalent.
5794 This filter accepts the following options:
5797 Set the deinterlacing mode.
5799 It accepts one of the following values:
5804 use iterative motion estimation
5806 like @samp{slow}, but use multiple reference frames.
5808 Default value is @samp{fast}.
5811 Set the picture field parity assumed for the input video. It must be
5812 one of the following values:
5816 assume top field first
5818 assume bottom field first
5821 Default value is @samp{bff}.
5824 Set per-block quantization parameter (QP) used by the internal
5827 Higher values should result in a smoother motion vector field but less
5828 optimal individual vectors. Default value is 1.
5833 Apply an MPlayer filter to the input video.
5835 This filter provides a wrapper around some of the filters of
5838 This wrapper is considered experimental. Some of the wrapped filters
5839 may not work properly and we may drop support for them, as they will
5840 be implemented natively into FFmpeg. Thus you should avoid
5841 depending on them when writing portable scripts.
5843 The filter accepts the parameters:
5844 @var{filter_name}[:=]@var{filter_params}
5846 @var{filter_name} is the name of a supported MPlayer filter,
5847 @var{filter_params} is a string containing the parameters accepted by
5850 The list of the currently supported filters follows:
5861 The parameter syntax and behavior for the listed filters are the same
5862 of the corresponding MPlayer filters. For detailed instructions check
5863 the "VIDEO FILTERS" section in the MPlayer manual.
5865 @subsection Examples
5869 Adjust gamma, brightness, contrast:
5875 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
5879 Drop frames that do not differ greatly from the previous frame in
5880 order to reduce frame rate.
5882 The main use of this filter is for very-low-bitrate encoding
5883 (e.g. streaming over dialup modem), but it could in theory be used for
5884 fixing movies that were inverse-telecined incorrectly.
5886 A description of the accepted options follows.
5890 Set the maximum number of consecutive frames which can be dropped (if
5891 positive), or the minimum interval between dropped frames (if
5892 negative). If the value is 0, the frame is dropped unregarding the
5893 number of previous sequentially dropped frames.
5900 Set the dropping threshold values.
5902 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
5903 represent actual pixel value differences, so a threshold of 64
5904 corresponds to 1 unit of difference for each pixel, or the same spread
5905 out differently over the block.
5907 A frame is a candidate for dropping if no 8x8 blocks differ by more
5908 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
5909 meaning the whole image) differ by more than a threshold of @option{lo}.
5911 Default value for @option{hi} is 64*12, default value for @option{lo} is
5912 64*5, and default value for @option{frac} is 0.33.
5920 It accepts an integer in input; if non-zero it negates the
5921 alpha component (if available). The default value in input is 0.
5925 Force libavfilter not to use any of the specified pixel formats for the
5926 input to the next filter.
5928 It accepts the following parameters:
5932 A '|'-separated list of pixel format names, such as
5933 apix_fmts=yuv420p|monow|rgb24".
5937 @subsection Examples
5941 Force libavfilter to use a format different from @var{yuv420p} for the
5942 input to the vflip filter:
5944 noformat=pix_fmts=yuv420p,vflip
5948 Convert the input video to any of the formats not contained in the list:
5950 noformat=yuv420p|yuv444p|yuv410p
5956 Add noise on video input frame.
5958 The filter accepts the following options:
5966 Set noise seed for specific pixel component or all pixel components in case
5967 of @var{all_seed}. Default value is @code{123457}.
5969 @item all_strength, alls
5970 @item c0_strength, c0s
5971 @item c1_strength, c1s
5972 @item c2_strength, c2s
5973 @item c3_strength, c3s
5974 Set noise strength for specific pixel component or all pixel components in case
5975 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
5977 @item all_flags, allf
5982 Set pixel component flags or set flags for all components if @var{all_flags}.
5983 Available values for component flags are:
5986 averaged temporal noise (smoother)
5988 mix random noise with a (semi)regular pattern
5990 temporal noise (noise pattern changes between frames)
5992 uniform noise (gaussian otherwise)
5996 @subsection Examples
5998 Add temporal and uniform noise to input video:
6000 noise=alls=20:allf=t+u
6005 Pass the video source unchanged to the output.
6009 Apply a video transform using libopencv.
6011 To enable this filter, install the libopencv library and headers and
6012 configure FFmpeg with @code{--enable-libopencv}.
6014 It accepts the following parameters:
6019 The name of the libopencv filter to apply.
6022 The parameters to pass to the libopencv filter. If not specified, the default
6027 Refer to the official libopencv documentation for more precise
6029 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
6031 Several libopencv filters are supported; see the following subsections.
6036 Dilate an image by using a specific structuring element.
6037 It corresponds to the libopencv function @code{cvDilate}.
6039 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
6041 @var{struct_el} represents a structuring element, and has the syntax:
6042 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
6044 @var{cols} and @var{rows} represent the number of columns and rows of
6045 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
6046 point, and @var{shape} the shape for the structuring element. @var{shape}
6047 must be "rect", "cross", "ellipse", or "custom".
6049 If the value for @var{shape} is "custom", it must be followed by a
6050 string of the form "=@var{filename}". The file with name
6051 @var{filename} is assumed to represent a binary image, with each
6052 printable character corresponding to a bright pixel. When a custom
6053 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
6054 or columns and rows of the read file are assumed instead.
6056 The default value for @var{struct_el} is "3x3+0x0/rect".
6058 @var{nb_iterations} specifies the number of times the transform is
6059 applied to the image, and defaults to 1.
6063 # Use the default values
6066 # Dilate using a structuring element with a 5x5 cross, iterating two times
6067 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
6069 # Read the shape from the file diamond.shape, iterating two times.
6070 # The file diamond.shape may contain a pattern of characters like this
6076 # The specified columns and rows are ignored
6077 # but the anchor point coordinates are not
6078 ocv=dilate:0x0+2x2/custom=diamond.shape|2
6083 Erode an image by using a specific structuring element.
6084 It corresponds to the libopencv function @code{cvErode}.
6086 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
6087 with the same syntax and semantics as the @ref{dilate} filter.
6091 Smooth the input video.
6093 The filter takes the following parameters:
6094 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
6096 @var{type} is the type of smooth filter to apply, and must be one of
6097 the following values: "blur", "blur_no_scale", "median", "gaussian",
6098 or "bilateral". The default value is "gaussian".
6100 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
6101 depend on the smooth type. @var{param1} and
6102 @var{param2} accept integer positive values or 0. @var{param3} and
6103 @var{param4} accept floating point values.
6105 The default value for @var{param1} is 3. The default value for the
6106 other parameters is 0.
6108 These parameters correspond to the parameters assigned to the
6109 libopencv function @code{cvSmooth}.
6114 Overlay one video on top of another.
6116 It takes two inputs and has one output. The first input is the "main"
6117 video on which the second input is overlayed.
6119 It accepts the following parameters:
6121 A description of the accepted options follows.
6126 Set the expression for the x and y coordinates of the overlayed video
6127 on the main video. Default value is "0" for both expressions. In case
6128 the expression is invalid, it is set to a huge value (meaning that the
6129 overlay will not be displayed within the output visible area).
6132 The action to take when EOF is encountered on the secondary input; it accepts
6133 one of the following values:
6137 Repeat the last frame (the default).
6141 Pass the main input through.
6145 Set when the expressions for @option{x}, and @option{y} are evaluated.
6147 It accepts the following values:
6150 only evaluate expressions once during the filter initialization or
6151 when a command is processed
6154 evaluate expressions for each incoming frame
6157 Default value is @samp{frame}.
6160 If set to 1, force the output to terminate when the shortest input
6161 terminates. Default value is 0.
6164 Set the format for the output video.
6166 It accepts the following values:
6181 Default value is @samp{yuv420}.
6183 @item rgb @emph{(deprecated)}
6184 If set to 1, force the filter to accept inputs in the RGB
6185 color space. Default value is 0. This option is deprecated, use
6186 @option{format} instead.
6189 If set to 1, force the filter to draw the last overlay frame over the
6190 main input until the end of the stream. A value of 0 disables this
6191 behavior. Default value is 1.
6194 The @option{x}, and @option{y} expressions can contain the following
6200 The main input width and height.
6204 The overlay input width and height.
6208 The computed values for @var{x} and @var{y}. They are evaluated for
6213 horizontal and vertical chroma subsample values of the output
6214 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6218 the number of input frame, starting from 0
6221 the position in the file of the input frame, NAN if unknown
6224 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6228 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6229 when evaluation is done @emph{per frame}, and will evaluate to NAN
6230 when @option{eval} is set to @samp{init}.
6232 Be aware that frames are taken from each input video in timestamp
6233 order, hence, if their initial timestamps differ, it is a good idea
6234 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6235 have them begin in the same zero timestamp, as the example for
6236 the @var{movie} filter does.
6238 You can chain together more overlays but you should test the
6239 efficiency of such approach.
6241 @subsection Commands
6243 This filter supports the following commands:
6247 Modify the x and y of the overlay input.
6248 The command accepts the same syntax of the corresponding option.
6250 If the specified expression is not valid, it is kept at its current
6254 @subsection Examples
6258 Draw the overlay at 10 pixels from the bottom right corner of the main
6261 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6264 Using named options the example above becomes:
6266 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6270 Insert a transparent PNG logo in the bottom left corner of the input,
6271 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6273 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6277 Insert 2 different transparent PNG logos (second logo on bottom
6278 right corner) using the @command{ffmpeg} tool:
6280 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
6284 Add a transparent color layer on top of the main video; @code{WxH}
6285 must specify the size of the main input to the overlay filter:
6287 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6291 Play an original video and a filtered version (here with the deshake
6292 filter) side by side using the @command{ffplay} tool:
6294 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6297 The above command is the same as:
6299 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6303 Make a sliding overlay appearing from the left to the right top part of the
6304 screen starting since time 2:
6306 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6310 Compose output by putting two input videos side to side:
6312 ffmpeg -i left.avi -i right.avi -filter_complex "
6313 nullsrc=size=200x100 [background];
6314 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6315 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6316 [background][left] overlay=shortest=1 [background+left];
6317 [background+left][right] overlay=shortest=1:x=100 [left+right]
6322 Mask 10-20 seconds of a video by applying the delogo filter to a section
6324 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6325 -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]'
6330 Chain several overlays in cascade:
6332 nullsrc=s=200x200 [bg];
6333 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6334 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6335 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6336 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6337 [in3] null, [mid2] overlay=100:100 [out0]
6344 Apply Overcomplete Wavelet denoiser.
6346 The filter accepts the following options:
6352 Larger depth values will denoise lower frequency components more, but
6353 slow down filtering.
6355 Must be an int in the range 8-16, default is @code{8}.
6357 @item luma_strength, ls
6360 Must be a double value in the range 0-1000, default is @code{1.0}.
6362 @item chroma_strength, cs
6363 Set chroma strength.
6365 Must be a double value in the range 0-1000, default is @code{1.0}.
6370 Add paddings to the input image, and place the original input at the
6371 provided @var{x}, @var{y} coordinates.
6373 It accepts the following parameters:
6378 Specify an expression for the size of the output image with the
6379 paddings added. If the value for @var{width} or @var{height} is 0, the
6380 corresponding input size is used for the output.
6382 The @var{width} expression can reference the value set by the
6383 @var{height} expression, and vice versa.
6385 The default value of @var{width} and @var{height} is 0.
6389 Specify the offsets to place the input image at within the padded area,
6390 with respect to the top/left border of the output image.
6392 The @var{x} expression can reference the value set by the @var{y}
6393 expression, and vice versa.
6395 The default value of @var{x} and @var{y} is 0.
6398 Specify the color of the padded area. For the syntax of this option,
6399 check the "Color" section in the ffmpeg-utils manual.
6401 The default value of @var{color} is "black".
6404 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6405 options are expressions containing the following constants:
6410 The input video width and height.
6414 These are the same as @var{in_w} and @var{in_h}.
6418 The output width and height (the size of the padded area), as
6419 specified by the @var{width} and @var{height} expressions.
6423 These are the same as @var{out_w} and @var{out_h}.
6427 The x and y offsets as specified by the @var{x} and @var{y}
6428 expressions, or NAN if not yet specified.
6431 same as @var{iw} / @var{ih}
6434 input sample aspect ratio
6437 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6441 The horizontal and vertical chroma subsample values. For example for the
6442 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6445 @subsection Examples
6449 Add paddings with the color "violet" to the input video. The output video
6450 size is 640x480, and the top-left corner of the input video is placed at
6453 pad=640:480:0:40:violet
6456 The example above is equivalent to the following command:
6458 pad=width=640:height=480:x=0:y=40:color=violet
6462 Pad the input to get an output with dimensions increased by 3/2,
6463 and put the input video at the center of the padded area:
6465 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6469 Pad the input to get a squared output with size equal to the maximum
6470 value between the input width and height, and put the input video at
6471 the center of the padded area:
6473 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6477 Pad the input to get a final w/h ratio of 16:9:
6479 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6483 In case of anamorphic video, in order to set the output display aspect
6484 correctly, it is necessary to use @var{sar} in the expression,
6485 according to the relation:
6487 (ih * X / ih) * sar = output_dar
6488 X = output_dar / sar
6491 Thus the previous example needs to be modified to:
6493 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6497 Double the output size and put the input video in the bottom-right
6498 corner of the output padded area:
6500 pad="2*iw:2*ih:ow-iw:oh-ih"
6504 @section perspective
6506 Correct perspective of video not recorded perpendicular to the screen.
6508 A description of the accepted parameters follows.
6519 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6520 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6522 The expressions can use the following variables:
6527 the width and height of video frame.
6531 Set interpolation for perspective correction.
6533 It accepts the following values:
6539 Default value is @samp{linear}.
6544 Delay interlaced video by one field time so that the field order changes.
6546 The intended use is to fix PAL movies that have been captured with the
6547 opposite field order to the film-to-video transfer.
6549 A description of the accepted parameters follows.
6555 It accepts the following values:
6558 Capture field order top-first, transfer bottom-first.
6559 Filter will delay the bottom field.
6562 Capture field order bottom-first, transfer top-first.
6563 Filter will delay the top field.
6566 Capture and transfer with the same field order. This mode only exists
6567 for the documentation of the other options to refer to, but if you
6568 actually select it, the filter will faithfully do nothing.
6571 Capture field order determined automatically by field flags, transfer
6573 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6574 basis using field flags. If no field information is available,
6575 then this works just like @samp{u}.
6578 Capture unknown or varying, transfer opposite.
6579 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6580 analyzing the images and selecting the alternative that produces best
6581 match between the fields.
6584 Capture top-first, transfer unknown or varying.
6585 Filter selects among @samp{t} and @samp{p} using image analysis.
6588 Capture bottom-first, transfer unknown or varying.
6589 Filter selects among @samp{b} and @samp{p} using image analysis.
6592 Capture determined by field flags, transfer unknown or varying.
6593 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6594 image analysis. If no field information is available, then this works just
6595 like @samp{U}. This is the default mode.
6598 Both capture and transfer unknown or varying.
6599 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
6603 @section pixdesctest
6605 Pixel format descriptor test filter, mainly useful for internal
6606 testing. The output video should be equal to the input video.
6610 format=monow, pixdesctest
6613 can be used to test the monowhite pixel format descriptor definition.
6617 Enable the specified chain of postprocessing subfilters using libpostproc. This
6618 library should be automatically selected with a GPL build (@code{--enable-gpl}).
6619 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
6620 Each subfilter and some options have a short and a long name that can be used
6621 interchangeably, i.e. dr/dering are the same.
6623 The filters accept the following options:
6627 Set postprocessing subfilters string.
6630 All subfilters share common options to determine their scope:
6634 Honor the quality commands for this subfilter.
6637 Do chrominance filtering, too (default).
6640 Do luminance filtering only (no chrominance).
6643 Do chrominance filtering only (no luminance).
6646 These options can be appended after the subfilter name, separated by a '|'.
6648 Available subfilters are:
6651 @item hb/hdeblock[|difference[|flatness]]
6652 Horizontal deblocking filter
6655 Difference factor where higher values mean more deblocking (default: @code{32}).
6657 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6660 @item vb/vdeblock[|difference[|flatness]]
6661 Vertical deblocking filter
6664 Difference factor where higher values mean more deblocking (default: @code{32}).
6666 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6669 @item ha/hadeblock[|difference[|flatness]]
6670 Accurate horizontal deblocking filter
6673 Difference factor where higher values mean more deblocking (default: @code{32}).
6675 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6678 @item va/vadeblock[|difference[|flatness]]
6679 Accurate vertical deblocking filter
6682 Difference factor where higher values mean more deblocking (default: @code{32}).
6684 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6688 The horizontal and vertical deblocking filters share the difference and
6689 flatness values so you cannot set different horizontal and vertical
6694 Experimental horizontal deblocking filter
6697 Experimental vertical deblocking filter
6702 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
6705 larger -> stronger filtering
6707 larger -> stronger filtering
6709 larger -> stronger filtering
6712 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
6715 Stretch luminance to @code{0-255}.
6718 @item lb/linblenddeint
6719 Linear blend deinterlacing filter that deinterlaces the given block by
6720 filtering all lines with a @code{(1 2 1)} filter.
6722 @item li/linipoldeint
6723 Linear interpolating deinterlacing filter that deinterlaces the given block by
6724 linearly interpolating every second line.
6726 @item ci/cubicipoldeint
6727 Cubic interpolating deinterlacing filter deinterlaces the given block by
6728 cubically interpolating every second line.
6730 @item md/mediandeint
6731 Median deinterlacing filter that deinterlaces the given block by applying a
6732 median filter to every second line.
6734 @item fd/ffmpegdeint
6735 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
6736 second line with a @code{(-1 4 2 4 -1)} filter.
6739 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
6740 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
6742 @item fq/forceQuant[|quantizer]
6743 Overrides the quantizer table from the input with the constant quantizer you
6751 Default pp filter combination (@code{hb|a,vb|a,dr|a})
6754 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
6757 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
6760 @subsection Examples
6764 Apply horizontal and vertical deblocking, deringing and automatic
6765 brightness/contrast:
6771 Apply default filters without brightness/contrast correction:
6777 Apply default filters and temporal denoiser:
6779 pp=default/tmpnoise|1|2|3
6783 Apply deblocking on luminance only, and switch vertical deblocking on or off
6784 automatically depending on available CPU time:
6792 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
6793 Ratio) between two input videos.
6795 This filter takes in input two input videos, the first input is
6796 considered the "main" source and is passed unchanged to the
6797 output. The second input is used as a "reference" video for computing
6800 Both video inputs must have the same resolution and pixel format for
6801 this filter to work correctly. Also it assumes that both inputs
6802 have the same number of frames, which are compared one by one.
6804 The obtained average PSNR is printed through the logging system.
6806 The filter stores the accumulated MSE (mean squared error) of each
6807 frame, and at the end of the processing it is averaged across all frames
6808 equally, and the following formula is applied to obtain the PSNR:
6811 PSNR = 10*log10(MAX^2/MSE)
6814 Where MAX is the average of the maximum values of each component of the
6817 The description of the accepted parameters follows.
6821 If specified the filter will use the named file to save the PSNR of
6822 each individual frame.
6825 The file printed if @var{stats_file} is selected, contains a sequence of
6826 key/value pairs of the form @var{key}:@var{value} for each compared
6829 A description of each shown parameter follows:
6833 sequential number of the input frame, starting from 1
6836 Mean Square Error pixel-by-pixel average difference of the compared
6837 frames, averaged over all the image components.
6839 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
6840 Mean Square Error pixel-by-pixel average difference of the compared
6841 frames for the component specified by the suffix.
6843 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
6844 Peak Signal to Noise ratio of the compared frames for the component
6845 specified by the suffix.
6850 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
6851 [main][ref] psnr="stats_file=stats.log" [out]
6854 On this example the input file being processed is compared with the
6855 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
6856 is stored in @file{stats.log}.
6861 Pulldown reversal (inverse telecine) filter, capable of handling mixed
6862 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
6865 The pullup filter is designed to take advantage of future context in making
6866 its decisions. This filter is stateless in the sense that it does not lock
6867 onto a pattern to follow, but it instead looks forward to the following
6868 fields in order to identify matches and rebuild progressive frames.
6870 To produce content with an even framerate, insert the fps filter after
6871 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
6872 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
6874 The filter accepts the following options:
6881 These options set the amount of "junk" to ignore at the left, right, top, and
6882 bottom of the image, respectively. Left and right are in units of 8 pixels,
6883 while top and bottom are in units of 2 lines.
6884 The default is 8 pixels on each side.
6887 Set the strict breaks. Setting this option to 1 will reduce the chances of
6888 filter generating an occasional mismatched frame, but it may also cause an
6889 excessive number of frames to be dropped during high motion sequences.
6890 Conversely, setting it to -1 will make filter match fields more easily.
6891 This may help processing of video where there is slight blurring between
6892 the fields, but may also cause there to be interlaced frames in the output.
6893 Default value is @code{0}.
6896 Set the metric plane to use. It accepts the following values:
6902 Use chroma blue plane.
6905 Use chroma red plane.
6908 This option may be set to use chroma plane instead of the default luma plane
6909 for doing filter's computations. This may improve accuracy on very clean
6910 source material, but more likely will decrease accuracy, especially if there
6911 is chroma noise (rainbow effect) or any grayscale video.
6912 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
6913 load and make pullup usable in realtime on slow machines.
6916 For best results (without duplicated frames in the output file) it is
6917 necessary to change the output frame rate. For example, to inverse
6918 telecine NTSC input:
6920 ffmpeg -i input -vf pullup -r 24000/1001 ...
6925 Suppress a TV station logo, using an image file to determine which
6926 pixels comprise the logo. It works by filling in the pixels that
6927 comprise the logo with neighboring pixels.
6929 The filter accepts the following options:
6933 Set the filter bitmap file, which can be any image format supported by
6934 libavformat. The width and height of the image file must match those of the
6935 video stream being processed.
6938 Pixels in the provided bitmap image with a value of zero are not
6939 considered part of the logo, non-zero pixels are considered part of
6940 the logo. If you use white (255) for the logo and black (0) for the
6941 rest, you will be safe. For making the filter bitmap, it is
6942 recommended to take a screen capture of a black frame with the logo
6943 visible, and then using a threshold filter followed by the erode
6944 filter once or twice.
6946 If needed, little splotches can be fixed manually. Remember that if
6947 logo pixels are not covered, the filter quality will be much
6948 reduced. Marking too many pixels as part of the logo does not hurt as
6949 much, but it will increase the amount of blurring needed to cover over
6950 the image and will destroy more information than necessary, and extra
6951 pixels will slow things down on a large logo.
6955 Rotate video by an arbitrary angle expressed in radians.
6957 The filter accepts the following options:
6959 A description of the optional parameters follows.
6962 Set an expression for the angle by which to rotate the input video
6963 clockwise, expressed as a number of radians. A negative value will
6964 result in a counter-clockwise rotation. By default it is set to "0".
6966 This expression is evaluated for each frame.
6969 Set the output width expression, default value is "iw".
6970 This expression is evaluated just once during configuration.
6973 Set the output height expression, default value is "ih".
6974 This expression is evaluated just once during configuration.
6977 Enable bilinear interpolation if set to 1, a value of 0 disables
6978 it. Default value is 1.
6981 Set the color used to fill the output area not covered by the rotated
6982 image. For the generalsyntax of this option, check the "Color" section in the
6983 ffmpeg-utils manual. If the special value "none" is selected then no
6984 background is printed (useful for example if the background is never shown).
6986 Default value is "black".
6989 The expressions for the angle and the output size can contain the
6990 following constants and functions:
6994 sequential number of the input frame, starting from 0. It is always NAN
6995 before the first frame is filtered.
6998 time in seconds of the input frame, it is set to 0 when the filter is
6999 configured. It is always NAN before the first frame is filtered.
7003 horizontal and vertical chroma subsample values. For example for the
7004 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7008 the input video width and height
7012 the output width and height, that is the size of the padded area as
7013 specified by the @var{width} and @var{height} expressions
7017 the minimal width/height required for completely containing the input
7018 video rotated by @var{a} radians.
7020 These are only available when computing the @option{out_w} and
7021 @option{out_h} expressions.
7024 @subsection Examples
7028 Rotate the input by PI/6 radians clockwise:
7034 Rotate the input by PI/6 radians counter-clockwise:
7040 Rotate the input by 45 degrees clockwise:
7046 Apply a constant rotation with period T, starting from an angle of PI/3:
7048 rotate=PI/3+2*PI*t/T
7052 Make the input video rotation oscillating with a period of T
7053 seconds and an amplitude of A radians:
7055 rotate=A*sin(2*PI/T*t)
7059 Rotate the video, output size is chosen so that the whole rotating
7060 input video is always completely contained in the output:
7062 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
7066 Rotate the video, reduce the output size so that no background is ever
7069 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
7073 @subsection Commands
7075 The filter supports the following commands:
7079 Set the angle expression.
7080 The command accepts the same syntax of the corresponding option.
7082 If the specified expression is not valid, it is kept at its current
7088 Apply Shape Adaptive Blur.
7090 The filter accepts the following options:
7093 @item luma_radius, lr
7094 Set luma blur filter strength, must be a value in range 0.1-4.0, default
7095 value is 1.0. A greater value will result in a more blurred image, and
7096 in slower processing.
7098 @item luma_pre_filter_radius, lpfr
7099 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
7102 @item luma_strength, ls
7103 Set luma maximum difference between pixels to still be considered, must
7104 be a value in the 0.1-100.0 range, default value is 1.0.
7106 @item chroma_radius, cr
7107 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
7108 greater value will result in a more blurred image, and in slower
7111 @item chroma_pre_filter_radius, cpfr
7112 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
7114 @item chroma_strength, cs
7115 Set chroma maximum difference between pixels to still be considered,
7116 must be a value in the 0.1-100.0 range.
7119 Each chroma option value, if not explicitly specified, is set to the
7120 corresponding luma option value.
7125 Scale (resize) the input video, using the libswscale library.
7127 The scale filter forces the output display aspect ratio to be the same
7128 of the input, by changing the output sample aspect ratio.
7130 If the input image format is different from the format requested by
7131 the next filter, the scale filter will convert the input to the
7135 The filter accepts the following options, or any of the options
7136 supported by the libswscale scaler.
7138 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
7139 the complete list of scaler options.
7144 Set the output video dimension expression. Default value is the input
7147 If the value is 0, the input width is used for the output.
7149 If one of the values is -1, the scale filter will use a value that
7150 maintains the aspect ratio of the input image, calculated from the
7151 other specified dimension. If both of them are -1, the input size is
7154 If one of the values is -n with n > 1, the scale filter will also use a value
7155 that maintains the aspect ratio of the input image, calculated from the other
7156 specified dimension. After that it will, however, make sure that the calculated
7157 dimension is divisible by n and adjust the value if necessary.
7159 See below for the list of accepted constants for use in the dimension
7163 Set the interlacing mode. It accepts the following values:
7167 Force interlaced aware scaling.
7170 Do not apply interlaced scaling.
7173 Select interlaced aware scaling depending on whether the source frames
7174 are flagged as interlaced or not.
7177 Default value is @samp{0}.
7180 Set libswscale scaling flags. See
7181 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7182 complete list of values. If not explicitly specified the filter applies
7186 Set the video size. For the syntax of this option, check the "Video size"
7187 section in the ffmpeg-utils manual.
7189 @item in_color_matrix
7190 @item out_color_matrix
7191 Set in/output YCbCr color space type.
7193 This allows the autodetected value to be overridden as well as allows forcing
7194 a specific value used for the output and encoder.
7196 If not specified, the color space type depends on the pixel format.
7202 Choose automatically.
7205 Format conforming to International Telecommunication Union (ITU)
7206 Recommendation BT.709.
7209 Set color space conforming to the United States Federal Communications
7210 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7213 Set color space conforming to:
7217 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7220 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7223 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7228 Set color space conforming to SMPTE ST 240:1999.
7233 Set in/output YCbCr sample range.
7235 This allows the autodetected value to be overridden as well as allows forcing
7236 a specific value used for the output and encoder. If not specified, the
7237 range depends on the pixel format. Possible values:
7241 Choose automatically.
7244 Set full range (0-255 in case of 8-bit luma).
7247 Set "MPEG" range (16-235 in case of 8-bit luma).
7250 @item force_original_aspect_ratio
7251 Enable decreasing or increasing output video width or height if necessary to
7252 keep the original aspect ratio. Possible values:
7256 Scale the video as specified and disable this feature.
7259 The output video dimensions will automatically be decreased if needed.
7262 The output video dimensions will automatically be increased if needed.
7266 One useful instance of this option is that when you know a specific device's
7267 maximum allowed resolution, you can use this to limit the output video to
7268 that, while retaining the aspect ratio. For example, device A allows
7269 1280x720 playback, and your video is 1920x800. Using this option (set it to
7270 decrease) and specifying 1280x720 to the command line makes the output
7273 Please note that this is a different thing than specifying -1 for @option{w}
7274 or @option{h}, you still need to specify the output resolution for this option
7279 The values of the @option{w} and @option{h} options are expressions
7280 containing the following constants:
7285 The input width and height
7289 These are the same as @var{in_w} and @var{in_h}.
7293 The output (scaled) width and height
7297 These are the same as @var{out_w} and @var{out_h}
7300 The same as @var{iw} / @var{ih}
7303 input sample aspect ratio
7306 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7310 horizontal and vertical input chroma subsample values. For example for the
7311 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7315 horizontal and vertical output chroma subsample values. For example for the
7316 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7319 @subsection Examples
7323 Scale the input video to a size of 200x100
7328 This is equivalent to:
7339 Specify a size abbreviation for the output size:
7344 which can also be written as:
7350 Scale the input to 2x:
7356 The above is the same as:
7362 Scale the input to 2x with forced interlaced scaling:
7364 scale=2*iw:2*ih:interl=1
7368 Scale the input to half size:
7374 Increase the width, and set the height to the same size:
7387 Increase the height, and set the width to 3/2 of the height:
7389 scale=w=3/2*oh:h=3/5*ih
7393 Increase the size, making the size a multiple of the chroma
7396 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7400 Increase the width to a maximum of 500 pixels,
7401 keeping the same aspect ratio as the input:
7403 scale=w='min(500\, iw*3/2):h=-1'
7407 @section separatefields
7409 The @code{separatefields} takes a frame-based video input and splits
7410 each frame into its components fields, producing a new half height clip
7411 with twice the frame rate and twice the frame count.
7413 This filter use field-dominance information in frame to decide which
7414 of each pair of fields to place first in the output.
7415 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7417 @section setdar, setsar
7419 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7422 This is done by changing the specified Sample (aka Pixel) Aspect
7423 Ratio, according to the following equation:
7425 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7428 Keep in mind that the @code{setdar} filter does not modify the pixel
7429 dimensions of the video frame. Also, the display aspect ratio set by
7430 this filter may be changed by later filters in the filterchain,
7431 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7434 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7435 the filter output video.
7437 Note that as a consequence of the application of this filter, the
7438 output display aspect ratio will change according to the equation
7441 Keep in mind that the sample aspect ratio set by the @code{setsar}
7442 filter may be changed by later filters in the filterchain, e.g. if
7443 another "setsar" or a "setdar" filter is applied.
7445 It accepts the following parameters:
7448 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7449 Set the aspect ratio used by the filter.
7451 The parameter can be a floating point number string, an expression, or
7452 a string of the form @var{num}:@var{den}, where @var{num} and
7453 @var{den} are the numerator and denominator of the aspect ratio. If
7454 the parameter is not specified, it is assumed the value "0".
7455 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7459 Set the maximum integer value to use for expressing numerator and
7460 denominator when reducing the expressed aspect ratio to a rational.
7461 Default value is @code{100}.
7465 The parameter @var{sar} is an expression containing
7466 the following constants:
7470 These are approximated values for the mathematical constants e
7471 (Euler's number), pi (Greek pi), and phi (the golden ratio).
7474 The input width and height.
7477 These are the same as @var{w} / @var{h}.
7480 The input sample aspect ratio.
7483 The input display aspect ratio. It is the same as
7484 (@var{w} / @var{h}) * @var{sar}.
7487 Horizontal and vertical chroma subsample values. For example, for the
7488 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7491 @subsection Examples
7496 To change the display aspect ratio to 16:9, specify one of the following:
7504 To change the sample aspect ratio to 10:11, specify:
7510 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7511 1000 in the aspect ratio reduction, use the command:
7513 setdar=ratio=16/9:max=1000
7521 Force field for the output video frame.
7523 The @code{setfield} filter marks the interlace type field for the
7524 output frames. It does not change the input frame, but only sets the
7525 corresponding property, which affects how the frame is treated by
7526 following filters (e.g. @code{fieldorder} or @code{yadif}).
7528 The filter accepts the following options:
7533 Available values are:
7537 Keep the same field property.
7540 Mark the frame as bottom-field-first.
7543 Mark the frame as top-field-first.
7546 Mark the frame as progressive.
7552 Show a line containing various information for each input video frame.
7553 The input video is not modified.
7555 The shown line contains a sequence of key/value pairs of the form
7556 @var{key}:@var{value}.
7558 It accepts the following parameters:
7562 The (sequential) number of the input frame, starting from 0.
7565 The Presentation TimeStamp of the input frame, expressed as a number of
7566 time base units. The time base unit depends on the filter input pad.
7569 The Presentation TimeStamp of the input frame, expressed as a number of
7573 The position of the frame in the input stream, or -1 if this information is
7574 unavailable and/or meaningless (for example in case of synthetic video).
7577 The pixel format name.
7580 The sample aspect ratio of the input frame, expressed in the form
7581 @var{num}/@var{den}.
7584 The size of the input frame. For the syntax of this option, check the "Video size"
7585 section in the ffmpeg-utils manual.
7588 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
7589 for bottom field first).
7592 This is 1 if the frame is a key frame, 0 otherwise.
7595 The picture type of the input frame ("I" for an I-frame, "P" for a
7596 P-frame, "B" for a B-frame, or "?" for an unknown type).
7597 Also refer to the documentation of the @code{AVPictureType} enum and of
7598 the @code{av_get_picture_type_char} function defined in
7599 @file{libavutil/avutil.h}.
7602 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
7604 @item plane_checksum
7605 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
7606 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
7609 @section shuffleplanes
7611 Reorder and/or duplicate video planes.
7613 It accepts the following parameters:
7618 The index of the input plane to be used as the first output plane.
7621 The index of the input plane to be used as the second output plane.
7624 The index of the input plane to be used as the third output plane.
7627 The index of the input plane to be used as the fourth output plane.
7631 The first plane has the index 0. The default is to keep the input unchanged.
7633 Swap the second and third planes of the input:
7635 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
7638 @section signalstats
7639 Evaluate various visual metrics that assist in determining issues associated
7640 with the digitization of analog video media.
7642 By default the filter will log these metadata values:
7646 Display the minimal Y value contained within the input frame. Expressed in
7650 Display the Y value at the 10% percentile within the input frame. Expressed in
7654 Display the average Y value within the input frame. Expressed in range of
7658 Display the Y value at the 90% percentile within the input frame. Expressed in
7662 Display the maximum Y value contained within the input frame. Expressed in
7666 Display the minimal U value contained within the input frame. Expressed in
7670 Display the U value at the 10% percentile within the input frame. Expressed in
7674 Display the average U value within the input frame. Expressed in range of
7678 Display the U value at the 90% percentile within the input frame. Expressed in
7682 Display the maximum U value contained within the input frame. Expressed in
7686 Display the minimal V value contained within the input frame. Expressed in
7690 Display the V value at the 10% percentile within the input frame. Expressed in
7694 Display the average V value within the input frame. Expressed in range of
7698 Display the V value at the 90% percentile within the input frame. Expressed in
7702 Display the maximum V value contained within the input frame. Expressed in
7706 Display the minimal saturation value contained within the input frame.
7707 Expressed in range of [0-~181.02].
7710 Display the saturation value at the 10% percentile within the input frame.
7711 Expressed in range of [0-~181.02].
7714 Display the average saturation value within the input frame. Expressed in range
7718 Display the saturation value at the 90% percentile within the input frame.
7719 Expressed in range of [0-~181.02].
7722 Display the maximum saturation value contained within the input frame.
7723 Expressed in range of [0-~181.02].
7726 Display the median value for hue within the input frame. Expressed in range of
7730 Display the average value for hue within the input frame. Expressed in range of
7734 Display the average of sample value difference between all values of the Y
7735 plane in the current frame and corresponding values of the previous input frame.
7736 Expressed in range of [0-255].
7739 Display the average of sample value difference between all values of the U
7740 plane in the current frame and corresponding values of the previous input frame.
7741 Expressed in range of [0-255].
7744 Display the average of sample value difference between all values of the V
7745 plane in the current frame and corresponding values of the previous input frame.
7746 Expressed in range of [0-255].
7749 The filter accepts the following options:
7755 @option{stat} specify an additional form of image analysis.
7756 @option{out} output video with the specified type of pixel highlighted.
7758 Both options accept the following values:
7762 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
7763 unlike the neighboring pixels of the same field. Examples of temporal outliers
7764 include the results of video dropouts, head clogs, or tape tracking issues.
7767 Identify @var{vertical line repetition}. Vertical line repetition includes
7768 similar rows of pixels within a frame. In born-digital video vertical line
7769 repetition is common, but this pattern is uncommon in video digitized from an
7770 analog source. When it occurs in video that results from the digitization of an
7771 analog source it can indicate concealment from a dropout compensator.
7774 Identify pixels that fall outside of legal broadcast range.
7778 Set the highlight color for the @option{out} option. The default color is
7782 @subsection Examples
7786 Output data of various video metrics:
7788 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
7792 Output specific data about the minimum and maximum values of the Y plane per frame:
7794 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
7798 Playback video while highlighting pixels that are outside of broadcast range in red.
7800 ffplay example.mov -vf signalstats="out=brng:color=red"
7804 Playback video with signalstats metadata drawn over the frame.
7806 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
7809 The contents of signalstat_drawtext.txt used in the command are:
7812 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
7813 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
7814 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
7815 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
7823 Blur the input video without impacting the outlines.
7825 It accepts the following options:
7828 @item luma_radius, lr
7829 Set the luma radius. The option value must be a float number in
7830 the range [0.1,5.0] that specifies the variance of the gaussian filter
7831 used to blur the image (slower if larger). Default value is 1.0.
7833 @item luma_strength, ls
7834 Set the luma strength. The option value must be a float number
7835 in the range [-1.0,1.0] that configures the blurring. A value included
7836 in [0.0,1.0] will blur the image whereas a value included in
7837 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7839 @item luma_threshold, lt
7840 Set the luma threshold used as a coefficient to determine
7841 whether a pixel should be blurred or not. The option value must be an
7842 integer in the range [-30,30]. A value of 0 will filter all the image,
7843 a value included in [0,30] will filter flat areas and a value included
7844 in [-30,0] will filter edges. Default value is 0.
7846 @item chroma_radius, cr
7847 Set the chroma radius. The option value must be a float number in
7848 the range [0.1,5.0] that specifies the variance of the gaussian filter
7849 used to blur the image (slower if larger). Default value is 1.0.
7851 @item chroma_strength, cs
7852 Set the chroma strength. The option value must be a float number
7853 in the range [-1.0,1.0] that configures the blurring. A value included
7854 in [0.0,1.0] will blur the image whereas a value included in
7855 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7857 @item chroma_threshold, ct
7858 Set the chroma threshold used as a coefficient to determine
7859 whether a pixel should be blurred or not. The option value must be an
7860 integer in the range [-30,30]. A value of 0 will filter all the image,
7861 a value included in [0,30] will filter flat areas and a value included
7862 in [-30,0] will filter edges. Default value is 0.
7865 If a chroma option is not explicitly set, the corresponding luma value
7870 Convert between different stereoscopic image formats.
7872 The filters accept the following options:
7876 Set stereoscopic image format of input.
7878 Available values for input image formats are:
7881 side by side parallel (left eye left, right eye right)
7884 side by side crosseye (right eye left, left eye right)
7887 side by side parallel with half width resolution
7888 (left eye left, right eye right)
7891 side by side crosseye with half width resolution
7892 (right eye left, left eye right)
7895 above-below (left eye above, right eye below)
7898 above-below (right eye above, left eye below)
7901 above-below with half height resolution
7902 (left eye above, right eye below)
7905 above-below with half height resolution
7906 (right eye above, left eye below)
7909 alternating frames (left eye first, right eye second)
7912 alternating frames (right eye first, left eye second)
7914 Default value is @samp{sbsl}.
7918 Set stereoscopic image format of output.
7920 Available values for output image formats are all the input formats as well as:
7923 anaglyph red/blue gray
7924 (red filter on left eye, blue filter on right eye)
7927 anaglyph red/green gray
7928 (red filter on left eye, green filter on right eye)
7931 anaglyph red/cyan gray
7932 (red filter on left eye, cyan filter on right eye)
7935 anaglyph red/cyan half colored
7936 (red filter on left eye, cyan filter on right eye)
7939 anaglyph red/cyan color
7940 (red filter on left eye, cyan filter on right eye)
7943 anaglyph red/cyan color optimized with the least squares projection of dubois
7944 (red filter on left eye, cyan filter on right eye)
7947 anaglyph green/magenta gray
7948 (green filter on left eye, magenta filter on right eye)
7951 anaglyph green/magenta half colored
7952 (green filter on left eye, magenta filter on right eye)
7955 anaglyph green/magenta colored
7956 (green filter on left eye, magenta filter on right eye)
7959 anaglyph green/magenta color optimized with the least squares projection of dubois
7960 (green filter on left eye, magenta filter on right eye)
7963 anaglyph yellow/blue gray
7964 (yellow filter on left eye, blue filter on right eye)
7967 anaglyph yellow/blue half colored
7968 (yellow filter on left eye, blue filter on right eye)
7971 anaglyph yellow/blue colored
7972 (yellow filter on left eye, blue filter on right eye)
7975 anaglyph yellow/blue color optimized with the least squares projection of dubois
7976 (yellow filter on left eye, blue filter on right eye)
7979 interleaved rows (left eye has top row, right eye starts on next row)
7982 interleaved rows (right eye has top row, left eye starts on next row)
7985 mono output (left eye only)
7988 mono output (right eye only)
7991 Default value is @samp{arcd}.
7994 @subsection Examples
7998 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
8004 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
8012 Apply a simple postprocessing filter that compresses and decompresses the image
8013 at several (or - in the case of @option{quality} level @code{6} - all) shifts
8014 and average the results.
8016 The filter accepts the following options:
8020 Set quality. This option defines the number of levels for averaging. It accepts
8021 an integer in the range 0-6. If set to @code{0}, the filter will have no
8022 effect. A value of @code{6} means the higher quality. For each increment of
8023 that value the speed drops by a factor of approximately 2. Default value is
8027 Force a constant quantization parameter. If not set, the filter will use the QP
8028 from the video stream (if available).
8031 Set thresholding mode. Available modes are:
8035 Set hard thresholding (default).
8037 Set soft thresholding (better de-ringing effect, but likely blurrier).
8041 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8042 option may cause flicker since the B-Frames have often larger QP. Default is
8043 @code{0} (not enabled).
8049 Draw subtitles on top of input video using the libass library.
8051 To enable compilation of this filter you need to configure FFmpeg with
8052 @code{--enable-libass}. This filter also requires a build with libavcodec and
8053 libavformat to convert the passed subtitles file to ASS (Advanced Substation
8054 Alpha) subtitles format.
8056 The filter accepts the following options:
8060 Set the filename of the subtitle file to read. It must be specified.
8063 Specify the size of the original video, the video for which the ASS file
8064 was composed. For the syntax of this option, check the "Video size" section in
8065 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
8066 this is necessary to correctly scale the fonts if the aspect ratio has been
8070 Set subtitles input character encoding. @code{subtitles} filter only. Only
8071 useful if not UTF-8.
8073 @item stream_index, si
8074 Set subtitles stream index. @code{subtitles} filter only.
8077 If the first key is not specified, it is assumed that the first value
8078 specifies the @option{filename}.
8080 For example, to render the file @file{sub.srt} on top of the input
8081 video, use the command:
8086 which is equivalent to:
8088 subtitles=filename=sub.srt
8091 To render the default subtitles stream from file @file{video.mkv}, use:
8096 To render the second subtitles stream from that file, use:
8098 subtitles=video.mkv:si=1
8103 Scale the input by 2x and smooth using the Super2xSaI (Scale and
8104 Interpolate) pixel art scaling algorithm.
8106 Useful for enlarging pixel art images without reducing sharpness.
8113 Apply telecine process to the video.
8115 This filter accepts the following options:
8124 The default value is @code{top}.
8128 A string of numbers representing the pulldown pattern you wish to apply.
8129 The default value is @code{23}.
8133 Some typical patterns:
8138 24p: 2332 (preferred)
8145 24p: 222222222223 ("Euro pulldown")
8151 Select the most representative frame in a given sequence of consecutive frames.
8153 The filter accepts the following options:
8157 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
8158 will pick one of them, and then handle the next batch of @var{n} frames until
8159 the end. Default is @code{100}.
8162 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
8163 value will result in a higher memory usage, so a high value is not recommended.
8165 @subsection Examples
8169 Extract one picture each 50 frames:
8175 Complete example of a thumbnail creation with @command{ffmpeg}:
8177 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
8183 Tile several successive frames together.
8185 The filter accepts the following options:
8190 Set the grid size (i.e. the number of lines and columns). For the syntax of
8191 this option, check the "Video size" section in the ffmpeg-utils manual.
8194 Set the maximum number of frames to render in the given area. It must be less
8195 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
8196 the area will be used.
8199 Set the outer border margin in pixels.
8202 Set the inner border thickness (i.e. the number of pixels between frames). For
8203 more advanced padding options (such as having different values for the edges),
8204 refer to the pad video filter.
8207 Specify the color of the unused areaFor the syntax of this option, check the
8208 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
8212 @subsection Examples
8216 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
8218 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
8220 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
8221 duplicating each output frame to accommodate the originally detected frame
8225 Display @code{5} pictures in an area of @code{3x2} frames,
8226 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
8227 mixed flat and named options:
8229 tile=3x2:nb_frames=5:padding=7:margin=2
8235 Perform various types of temporal field interlacing.
8237 Frames are counted starting from 1, so the first input frame is
8240 The filter accepts the following options:
8245 Specify the mode of the interlacing. This option can also be specified
8246 as a value alone. See below for a list of values for this option.
8248 Available values are:
8252 Move odd frames into the upper field, even into the lower field,
8253 generating a double height frame at half frame rate.
8256 Only output even frames, odd frames are dropped, generating a frame with
8257 unchanged height at half frame rate.
8260 Only output odd frames, even frames are dropped, generating a frame with
8261 unchanged height at half frame rate.
8264 Expand each frame to full height, but pad alternate lines with black,
8265 generating a frame with double height at the same input frame rate.
8267 @item interleave_top, 4
8268 Interleave the upper field from odd frames with the lower field from
8269 even frames, generating a frame with unchanged height at half frame rate.
8271 @item interleave_bottom, 5
8272 Interleave the lower field from odd frames with the upper field from
8273 even frames, generating a frame with unchanged height at half frame rate.
8275 @item interlacex2, 6
8276 Double frame rate with unchanged height. Frames are inserted each
8277 containing the second temporal field from the previous input frame and
8278 the first temporal field from the next input frame. This mode relies on
8279 the top_field_first flag. Useful for interlaced video displays with no
8280 field synchronisation.
8283 Numeric values are deprecated but are accepted for backward
8284 compatibility reasons.
8286 Default mode is @code{merge}.
8289 Specify flags influencing the filter process.
8291 Available value for @var{flags} is:
8294 @item low_pass_filter, vlfp
8295 Enable vertical low-pass filtering in the filter.
8296 Vertical low-pass filtering is required when creating an interlaced
8297 destination from a progressive source which contains high-frequency
8298 vertical detail. Filtering will reduce interlace 'twitter' and Moire
8301 Vertical low-pass filtering can only be enabled for @option{mode}
8302 @var{interleave_top} and @var{interleave_bottom}.
8309 Transpose rows with columns in the input video and optionally flip it.
8311 It accepts the following parameters:
8316 Specify the transposition direction.
8318 Can assume the following values:
8320 @item 0, 4, cclock_flip
8321 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
8329 Rotate by 90 degrees clockwise, that is:
8337 Rotate by 90 degrees counterclockwise, that is:
8344 @item 3, 7, clock_flip
8345 Rotate by 90 degrees clockwise and vertically flip, that is:
8353 For values between 4-7, the transposition is only done if the input
8354 video geometry is portrait and not landscape. These values are
8355 deprecated, the @code{passthrough} option should be used instead.
8357 Numerical values are deprecated, and should be dropped in favor of
8361 Do not apply the transposition if the input geometry matches the one
8362 specified by the specified value. It accepts the following values:
8365 Always apply transposition.
8367 Preserve portrait geometry (when @var{height} >= @var{width}).
8369 Preserve landscape geometry (when @var{width} >= @var{height}).
8372 Default value is @code{none}.
8375 For example to rotate by 90 degrees clockwise and preserve portrait
8378 transpose=dir=1:passthrough=portrait
8381 The command above can also be specified as:
8383 transpose=1:portrait
8387 Trim the input so that the output contains one continuous subpart of the input.
8389 It accepts the following parameters:
8392 Specify the time of the start of the kept section, i.e. the frame with the
8393 timestamp @var{start} will be the first frame in the output.
8396 Specify the time of the first frame that will be dropped, i.e. the frame
8397 immediately preceding the one with the timestamp @var{end} will be the last
8398 frame in the output.
8401 This is the same as @var{start}, except this option sets the start timestamp
8402 in timebase units instead of seconds.
8405 This is the same as @var{end}, except this option sets the end timestamp
8406 in timebase units instead of seconds.
8409 The maximum duration of the output in seconds.
8412 The number of the first frame that should be passed to the output.
8415 The number of the first frame that should be dropped.
8418 @option{start}, @option{end}, @option{duration} are expressed as time
8419 duration specifications, check the "Time duration" section in the
8420 ffmpeg-utils manual.
8422 Note that the first two sets of the start/end options and the @option{duration}
8423 option look at the frame timestamp, while the _frame variants simply count the
8424 frames that pass through the filter. Also note that this filter does not modify
8425 the timestamps. If you wish for the output timestamps to start at zero, insert a
8426 setpts filter after the trim filter.
8428 If multiple start or end options are set, this filter tries to be greedy and
8429 keep all the frames that match at least one of the specified constraints. To keep
8430 only the part that matches all the constraints at once, chain multiple trim
8433 The defaults are such that all the input is kept. So it is possible to set e.g.
8434 just the end values to keep everything before the specified time.
8439 Drop everything except the second minute of input:
8441 ffmpeg -i INPUT -vf trim=60:120
8445 Keep only the first second:
8447 ffmpeg -i INPUT -vf trim=duration=1
8455 Sharpen or blur the input video.
8457 It accepts the following parameters:
8460 @item luma_msize_x, lx
8461 Set the luma matrix horizontal size. It must be an odd integer between
8462 3 and 63. The default value is 5.
8464 @item luma_msize_y, ly
8465 Set the luma matrix vertical size. It must be an odd integer between 3
8466 and 63. The default value is 5.
8468 @item luma_amount, la
8469 Set the luma effect strength. It must be a floating point number, reasonable
8470 values lay between -1.5 and 1.5.
8472 Negative values will blur the input video, while positive values will
8473 sharpen it, a value of zero will disable the effect.
8475 Default value is 1.0.
8477 @item chroma_msize_x, cx
8478 Set the chroma matrix horizontal size. It must be an odd integer
8479 between 3 and 63. The default value is 5.
8481 @item chroma_msize_y, cy
8482 Set the chroma matrix vertical size. It must be an odd integer
8483 between 3 and 63. The default value is 5.
8485 @item chroma_amount, ca
8486 Set the chroma effect strength. It must be a floating point number, reasonable
8487 values lay between -1.5 and 1.5.
8489 Negative values will blur the input video, while positive values will
8490 sharpen it, a value of zero will disable the effect.
8492 Default value is 0.0.
8495 If set to 1, specify using OpenCL capabilities, only available if
8496 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
8500 All parameters are optional and default to the equivalent of the
8501 string '5:5:1.0:5:5:0.0'.
8503 @subsection Examples
8507 Apply strong luma sharpen effect:
8509 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
8513 Apply a strong blur of both luma and chroma parameters:
8515 unsharp=7:7:-2:7:7:-2
8519 @anchor{vidstabdetect}
8520 @section vidstabdetect
8522 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
8523 @ref{vidstabtransform} for pass 2.
8525 This filter generates a file with relative translation and rotation
8526 transform information about subsequent frames, which is then used by
8527 the @ref{vidstabtransform} filter.
8529 To enable compilation of this filter you need to configure FFmpeg with
8530 @code{--enable-libvidstab}.
8532 This filter accepts the following options:
8536 Set the path to the file used to write the transforms information.
8537 Default value is @file{transforms.trf}.
8540 Set how shaky the video is and how quick the camera is. It accepts an
8541 integer in the range 1-10, a value of 1 means little shakiness, a
8542 value of 10 means strong shakiness. Default value is 5.
8545 Set the accuracy of the detection process. It must be a value in the
8546 range 1-15. A value of 1 means low accuracy, a value of 15 means high
8547 accuracy. Default value is 15.
8550 Set stepsize of the search process. The region around minimum is
8551 scanned with 1 pixel resolution. Default value is 6.
8554 Set minimum contrast. Below this value a local measurement field is
8555 discarded. Must be a floating point value in the range 0-1. Default
8559 Set reference frame number for tripod mode.
8561 If enabled, the motion of the frames is compared to a reference frame
8562 in the filtered stream, identified by the specified number. The idea
8563 is to compensate all movements in a more-or-less static scene and keep
8564 the camera view absolutely still.
8566 If set to 0, it is disabled. The frames are counted starting from 1.
8569 Show fields and transforms in the resulting frames. It accepts an
8570 integer in the range 0-2. Default value is 0, which disables any
8574 @subsection Examples
8584 Analyze strongly shaky movie and put the results in file
8585 @file{mytransforms.trf}:
8587 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
8591 Visualize the result of internal transformations in the resulting
8594 vidstabdetect=show=1
8598 Analyze a video with medium shakiness using @command{ffmpeg}:
8600 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
8604 @anchor{vidstabtransform}
8605 @section vidstabtransform
8607 Video stabilization/deshaking: pass 2 of 2,
8608 see @ref{vidstabdetect} for pass 1.
8610 Read a file with transform information for each frame and
8611 apply/compensate them. Together with the @ref{vidstabdetect}
8612 filter this can be used to deshake videos. See also
8613 @url{http://public.hronopik.de/vid.stab}. It is important to also use
8614 the unsharp filter, see below.
8616 To enable compilation of this filter you need to configure FFmpeg with
8617 @code{--enable-libvidstab}.
8623 Set path to the file used to read the transforms. Default value is
8624 @file{transforms.trf}).
8627 Set the number of frames (value*2 + 1) used for lowpass filtering the
8628 camera movements. Default value is 10.
8630 For example a number of 10 means that 21 frames are used (10 in the
8631 past and 10 in the future) to smoothen the motion in the video. A
8632 larger values leads to a smoother video, but limits the acceleration
8633 of the camera (pan/tilt movements). 0 is a special case where a
8634 static camera is simulated.
8637 Set the camera path optimization algorithm.
8639 Accepted values are:
8642 gaussian kernel low-pass filter on camera motion (default)
8644 averaging on transformations
8648 Set maximal number of pixels to translate frames. Default value is -1,
8652 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
8653 value is -1, meaning no limit.
8656 Specify how to deal with borders that may be visible due to movement
8659 Available values are:
8662 keep image information from previous frame (default)
8664 fill the border black
8668 Invert transforms if set to 1. Default value is 0.
8671 Consider transforms as relative to previsou frame if set to 1,
8672 absolute if set to 0. Default value is 0.
8675 Set percentage to zoom. A positive value will result in a zoom-in
8676 effect, a negative value in a zoom-out effect. Default value is 0 (no
8680 Set optimal zooming to avoid borders.
8682 Accepted values are:
8687 optimal static zoom value is determined (only very strong movements
8688 will lead to visible borders) (default)
8690 optimal adaptive zoom value is determined (no borders will be
8691 visible), see @option{zoomspeed}
8694 Note that the value given at zoom is added to the one calculated here.
8697 Set percent to zoom maximally each frame (enabled when
8698 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
8702 Specify type of interpolation.
8704 Available values are:
8709 linear only horizontal
8711 linear in both directions (default)
8713 cubic in both directions (slow)
8717 Enable virtual tripod mode if set to 1, which is equivalent to
8718 @code{relative=0:smoothing=0}. Default value is 0.
8720 Use also @code{tripod} option of @ref{vidstabdetect}.
8723 Increase log verbosity if set to 1. Also the detected global motions
8724 are written to the temporary file @file{global_motions.trf}. Default
8728 @subsection Examples
8732 Use @command{ffmpeg} for a typical stabilization with default values:
8734 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
8737 Note the use of the unsharp filter which is always recommended.
8740 Zoom in a bit more and load transform data from a given file:
8742 vidstabtransform=zoom=5:input="mytransforms.trf"
8746 Smoothen the video even more:
8748 vidstabtransform=smoothing=30
8754 Flip the input video vertically.
8756 For example, to vertically flip a video with @command{ffmpeg}:
8758 ffmpeg -i in.avi -vf "vflip" out.avi
8763 Make or reverse a natural vignetting effect.
8765 The filter accepts the following options:
8769 Set lens angle expression as a number of radians.
8771 The value is clipped in the @code{[0,PI/2]} range.
8773 Default value: @code{"PI/5"}
8777 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
8781 Set forward/backward mode.
8783 Available modes are:
8786 The larger the distance from the central point, the darker the image becomes.
8789 The larger the distance from the central point, the brighter the image becomes.
8790 This can be used to reverse a vignette effect, though there is no automatic
8791 detection to extract the lens @option{angle} and other settings (yet). It can
8792 also be used to create a burning effect.
8795 Default value is @samp{forward}.
8798 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
8800 It accepts the following values:
8803 Evaluate expressions only once during the filter initialization.
8806 Evaluate expressions for each incoming frame. This is way slower than the
8807 @samp{init} mode since it requires all the scalers to be re-computed, but it
8808 allows advanced dynamic expressions.
8811 Default value is @samp{init}.
8814 Set dithering to reduce the circular banding effects. Default is @code{1}
8818 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
8819 Setting this value to the SAR of the input will make a rectangular vignetting
8820 following the dimensions of the video.
8822 Default is @code{1/1}.
8825 @subsection Expressions
8827 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
8828 following parameters.
8833 input width and height
8836 the number of input frame, starting from 0
8839 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
8840 @var{TB} units, NAN if undefined
8843 frame rate of the input video, NAN if the input frame rate is unknown
8846 the PTS (Presentation TimeStamp) of the filtered video frame,
8847 expressed in seconds, NAN if undefined
8850 time base of the input video
8854 @subsection Examples
8858 Apply simple strong vignetting effect:
8864 Make a flickering vignetting:
8866 vignette='PI/4+random(1)*PI/50':eval=frame
8873 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
8874 Deinterlacing Filter").
8876 Based on the process described by Martin Weston for BBC R&D, and
8877 implemented based on the de-interlace algorithm written by Jim
8878 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
8879 uses filter coefficients calculated by BBC R&D.
8881 There are two sets of filter coefficients, so called "simple":
8882 and "complex". Which set of filter coefficients is used can
8883 be set by passing an optional parameter:
8887 Set the interlacing filter coefficients. Accepts one of the following values:
8891 Simple filter coefficient set.
8893 More-complex filter coefficient set.
8895 Default value is @samp{complex}.
8898 Specify which frames to deinterlace. Accept one of the following values:
8902 Deinterlace all frames,
8904 Only deinterlace frames marked as interlaced.
8907 Default value is @samp{all}.
8913 Deinterlace the input video ("yadif" means "yet another deinterlacing
8916 It accepts the following parameters:
8922 The interlacing mode to adopt. It accepts one of the following values:
8926 Output one frame for each frame.
8928 Output one frame for each field.
8929 @item 2, send_frame_nospatial
8930 Like @code{send_frame}, but it skips the spatial interlacing check.
8931 @item 3, send_field_nospatial
8932 Like @code{send_field}, but it skips the spatial interlacing check.
8935 The default value is @code{send_frame}.
8938 The picture field parity assumed for the input interlaced video. It accepts one
8939 of the following values:
8943 Assume the top field is first.
8945 Assume the bottom field is first.
8947 Enable automatic detection of field parity.
8950 The default value is @code{auto}.
8951 If the interlacing is unknown or the decoder does not export this information,
8952 top field first will be assumed.
8955 Specify which frames to deinterlace. Accept one of the following
8960 Deinterlace all frames.
8962 Only deinterlace frames marked as interlaced.
8965 The default value is @code{all}.
8970 Apply Zoom & Pan effect.
8972 This filter accepts the following options:
8976 Set the zoom expression. Default is 1.
8980 Set the x and y expression. Default is 0.
8983 Set the duration expression in number of frames.
8984 This sets for how many number of frames effect will last for
8988 Set the output image size, default is 'hd720'.
8991 Each expression can contain the following constants:
9014 Last calculated 'x' and 'y' position from 'x' and 'y' expression
9015 for current input frame.
9019 'x' and 'y' of last output frame of previous input frame or 0 when there was
9020 not yet such frame (first input frame).
9023 Last calculated zoom from 'z' expression for current input frame.
9026 Last calculated zoom of last output frame of previous input frame.
9029 Number of output frames for current input frame. Calculated from 'd' expression
9030 for each input frame.
9033 number of output frames created for previous input frame
9036 Rational number: input width / input height
9042 display aspect ratio
9046 @subsection Examples
9050 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
9052 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
9056 @c man end VIDEO FILTERS
9058 @chapter Video Sources
9059 @c man begin VIDEO SOURCES
9061 Below is a description of the currently available video sources.
9065 Buffer video frames, and make them available to the filter chain.
9067 This source is mainly intended for a programmatic use, in particular
9068 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
9070 It accepts the following parameters:
9075 Specify the size (width and height) of the buffered video frames. For the
9076 syntax of this option, check the "Video size" section in the ffmpeg-utils
9080 The input video width.
9083 The input video height.
9086 A string representing the pixel format of the buffered video frames.
9087 It may be a number corresponding to a pixel format, or a pixel format
9091 Specify the timebase assumed by the timestamps of the buffered frames.
9094 Specify the frame rate expected for the video stream.
9096 @item pixel_aspect, sar
9097 The sample (pixel) aspect ratio of the input video.
9100 Specify the optional parameters to be used for the scale filter which
9101 is automatically inserted when an input change is detected in the
9102 input size or format.
9107 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
9110 will instruct the source to accept video frames with size 320x240 and
9111 with format "yuv410p", assuming 1/24 as the timestamps timebase and
9112 square pixels (1:1 sample aspect ratio).
9113 Since the pixel format with name "yuv410p" corresponds to the number 6
9114 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
9115 this example corresponds to:
9117 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
9120 Alternatively, the options can be specified as a flat string, but this
9121 syntax is deprecated:
9123 @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}]
9127 Create a pattern generated by an elementary cellular automaton.
9129 The initial state of the cellular automaton can be defined through the
9130 @option{filename}, and @option{pattern} options. If such options are
9131 not specified an initial state is created randomly.
9133 At each new frame a new row in the video is filled with the result of
9134 the cellular automaton next generation. The behavior when the whole
9135 frame is filled is defined by the @option{scroll} option.
9137 This source accepts the following options:
9141 Read the initial cellular automaton state, i.e. the starting row, from
9143 In the file, each non-whitespace character is considered an alive
9144 cell, a newline will terminate the row, and further characters in the
9145 file will be ignored.
9148 Read the initial cellular automaton state, i.e. the starting row, from
9149 the specified string.
9151 Each non-whitespace character in the string is considered an alive
9152 cell, a newline will terminate the row, and further characters in the
9153 string will be ignored.
9156 Set the video rate, that is the number of frames generated per second.
9159 @item random_fill_ratio, ratio
9160 Set the random fill ratio for the initial cellular automaton row. It
9161 is a floating point number value ranging from 0 to 1, defaults to
9164 This option is ignored when a file or a pattern is specified.
9166 @item random_seed, seed
9167 Set the seed for filling randomly the initial row, must be an integer
9168 included between 0 and UINT32_MAX. If not specified, or if explicitly
9169 set to -1, the filter will try to use a good random seed on a best
9173 Set the cellular automaton rule, it is a number ranging from 0 to 255.
9174 Default value is 110.
9177 Set the size of the output video. For the syntax of this option, check
9178 the "Video size" section in the ffmpeg-utils manual.
9180 If @option{filename} or @option{pattern} is specified, the size is set
9181 by default to the width of the specified initial state row, and the
9182 height is set to @var{width} * PHI.
9184 If @option{size} is set, it must contain the width of the specified
9185 pattern string, and the specified pattern will be centered in the
9188 If a filename or a pattern string is not specified, the size value
9189 defaults to "320x518" (used for a randomly generated initial state).
9192 If set to 1, scroll the output upward when all the rows in the output
9193 have been already filled. If set to 0, the new generated row will be
9194 written over the top row just after the bottom row is filled.
9197 @item start_full, full
9198 If set to 1, completely fill the output with generated rows before
9199 outputting the first frame.
9200 This is the default behavior, for disabling set the value to 0.
9203 If set to 1, stitch the left and right row edges together.
9204 This is the default behavior, for disabling set the value to 0.
9207 @subsection Examples
9211 Read the initial state from @file{pattern}, and specify an output of
9214 cellauto=f=pattern:s=200x400
9218 Generate a random initial row with a width of 200 cells, with a fill
9221 cellauto=ratio=2/3:s=200x200
9225 Create a pattern generated by rule 18 starting by a single alive cell
9226 centered on an initial row with width 100:
9228 cellauto=p=@@:s=100x400:full=0:rule=18
9232 Specify a more elaborated initial pattern:
9234 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
9241 Generate a Mandelbrot set fractal, and progressively zoom towards the
9242 point specified with @var{start_x} and @var{start_y}.
9244 This source accepts the following options:
9249 Set the terminal pts value. Default value is 400.
9252 Set the terminal scale value.
9253 Must be a floating point value. Default value is 0.3.
9256 Set the inner coloring mode, that is the algorithm used to draw the
9257 Mandelbrot fractal internal region.
9259 It shall assume one of the following values:
9264 Show time until convergence.
9266 Set color based on point closest to the origin of the iterations.
9271 Default value is @var{mincol}.
9274 Set the bailout value. Default value is 10.0.
9277 Set the maximum of iterations performed by the rendering
9278 algorithm. Default value is 7189.
9281 Set outer coloring mode.
9282 It shall assume one of following values:
9284 @item iteration_count
9285 Set iteration cound mode.
9286 @item normalized_iteration_count
9287 set normalized iteration count mode.
9289 Default value is @var{normalized_iteration_count}.
9292 Set frame rate, expressed as number of frames per second. Default
9296 Set frame size. For the syntax of this option, check the "Video
9297 size" section in the ffmpeg-utils manual. Default value is "640x480".
9300 Set the initial scale value. Default value is 3.0.
9303 Set the initial x position. Must be a floating point value between
9304 -100 and 100. Default value is -0.743643887037158704752191506114774.
9307 Set the initial y position. Must be a floating point value between
9308 -100 and 100. Default value is -0.131825904205311970493132056385139.
9313 Generate various test patterns, as generated by the MPlayer test filter.
9315 The size of the generated video is fixed, and is 256x256.
9316 This source is useful in particular for testing encoding features.
9318 This source accepts the following options:
9323 Specify the frame rate of the sourced video, as the number of frames
9324 generated per second. It has to be a string in the format
9325 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9326 number or a valid video frame rate abbreviation. The default value is
9330 Set the video duration of the sourced video. The accepted syntax is:
9335 See also the function @code{av_parse_time()}.
9337 If not specified, or the expressed duration is negative, the video is
9338 supposed to be generated forever.
9342 Set the number or the name of the test to perform. Supported tests are:
9358 Default value is "all", which will cycle through the list of all tests.
9366 will generate a "dc_luma" test pattern.
9370 Provide a frei0r source.
9372 To enable compilation of this filter you need to install the frei0r
9373 header and configure FFmpeg with @code{--enable-frei0r}.
9375 This source accepts the following parameters:
9380 The size of the video to generate. For the syntax of this option, check the
9381 "Video size" section in the ffmpeg-utils manual.
9384 The framerate of the generated video. It may be a string of the form
9385 @var{num}/@var{den} or a frame rate abbreviation.
9388 The name to the frei0r source to load. For more information regarding frei0r and
9389 how to set the parameters, read the @ref{frei0r} section in the video filters
9393 A '|'-separated list of parameters to pass to the frei0r source.
9397 For example, to generate a frei0r partik0l source with size 200x200
9398 and frame rate 10 which is overlayed on the overlay filter main input:
9400 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
9405 Generate a life pattern.
9407 This source is based on a generalization of John Conway's life game.
9409 The sourced input represents a life grid, each pixel represents a cell
9410 which can be in one of two possible states, alive or dead. Every cell
9411 interacts with its eight neighbours, which are the cells that are
9412 horizontally, vertically, or diagonally adjacent.
9414 At each interaction the grid evolves according to the adopted rule,
9415 which specifies the number of neighbor alive cells which will make a
9416 cell stay alive or born. The @option{rule} option allows one to specify
9419 This source accepts the following options:
9423 Set the file from which to read the initial grid state. In the file,
9424 each non-whitespace character is considered an alive cell, and newline
9425 is used to delimit the end of each row.
9427 If this option is not specified, the initial grid is generated
9431 Set the video rate, that is the number of frames generated per second.
9434 @item random_fill_ratio, ratio
9435 Set the random fill ratio for the initial random grid. It is a
9436 floating point number value ranging from 0 to 1, defaults to 1/PHI.
9437 It is ignored when a file is specified.
9439 @item random_seed, seed
9440 Set the seed for filling the initial random grid, must be an integer
9441 included between 0 and UINT32_MAX. If not specified, or if explicitly
9442 set to -1, the filter will try to use a good random seed on a best
9448 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
9449 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
9450 @var{NS} specifies the number of alive neighbor cells which make a
9451 live cell stay alive, and @var{NB} the number of alive neighbor cells
9452 which make a dead cell to become alive (i.e. to "born").
9453 "s" and "b" can be used in place of "S" and "B", respectively.
9455 Alternatively a rule can be specified by an 18-bits integer. The 9
9456 high order bits are used to encode the next cell state if it is alive
9457 for each number of neighbor alive cells, the low order bits specify
9458 the rule for "borning" new cells. Higher order bits encode for an
9459 higher number of neighbor cells.
9460 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
9461 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
9463 Default value is "S23/B3", which is the original Conway's game of life
9464 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
9465 cells, and will born a new cell if there are three alive cells around
9469 Set the size of the output video. For the syntax of this option, check the
9470 "Video size" section in the ffmpeg-utils manual.
9472 If @option{filename} is specified, the size is set by default to the
9473 same size of the input file. If @option{size} is set, it must contain
9474 the size specified in the input file, and the initial grid defined in
9475 that file is centered in the larger resulting area.
9477 If a filename is not specified, the size value defaults to "320x240"
9478 (used for a randomly generated initial grid).
9481 If set to 1, stitch the left and right grid edges together, and the
9482 top and bottom edges also. Defaults to 1.
9485 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
9486 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
9487 value from 0 to 255.
9490 Set the color of living (or new born) cells.
9493 Set the color of dead cells. If @option{mold} is set, this is the first color
9494 used to represent a dead cell.
9497 Set mold color, for definitely dead and moldy cells.
9499 For the syntax of these 3 color options, check the "Color" section in the
9500 ffmpeg-utils manual.
9503 @subsection Examples
9507 Read a grid from @file{pattern}, and center it on a grid of size
9510 life=f=pattern:s=300x300
9514 Generate a random grid of size 200x200, with a fill ratio of 2/3:
9516 life=ratio=2/3:s=200x200
9520 Specify a custom rule for evolving a randomly generated grid:
9526 Full example with slow death effect (mold) using @command{ffplay}:
9528 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
9533 @anchor{haldclutsrc}
9537 @anchor{smptehdbars}
9539 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
9541 The @code{color} source provides an uniformly colored input.
9543 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
9544 @ref{haldclut} filter.
9546 The @code{nullsrc} source returns unprocessed video frames. It is
9547 mainly useful to be employed in analysis / debugging tools, or as the
9548 source for filters which ignore the input data.
9550 The @code{rgbtestsrc} source generates an RGB test pattern useful for
9551 detecting RGB vs BGR issues. You should see a red, green and blue
9552 stripe from top to bottom.
9554 The @code{smptebars} source generates a color bars pattern, based on
9555 the SMPTE Engineering Guideline EG 1-1990.
9557 The @code{smptehdbars} source generates a color bars pattern, based on
9558 the SMPTE RP 219-2002.
9560 The @code{testsrc} source generates a test video pattern, showing a
9561 color pattern, a scrolling gradient and a timestamp. This is mainly
9562 intended for testing purposes.
9564 The sources accept the following parameters:
9569 Specify the color of the source, only available in the @code{color}
9570 source. For the syntax of this option, check the "Color" section in the
9571 ffmpeg-utils manual.
9574 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
9575 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
9576 pixels to be used as identity matrix for 3D lookup tables. Each component is
9577 coded on a @code{1/(N*N)} scale.
9580 Specify the size of the sourced video. For the syntax of this option, check the
9581 "Video size" section in the ffmpeg-utils manual. The default value is
9584 This option is not available with the @code{haldclutsrc} filter.
9587 Specify the frame rate of the sourced video, as the number of frames
9588 generated per second. It has to be a string in the format
9589 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9590 number or a valid video frame rate abbreviation. The default value is
9594 Set the sample aspect ratio of the sourced video.
9597 Set the video duration of the sourced video. The accepted syntax is:
9599 [-]HH[:MM[:SS[.m...]]]
9602 Also see the the @code{av_parse_time()} function.
9604 If not specified, or the expressed duration is negative, the video is
9605 supposed to be generated forever.
9608 Set the number of decimals to show in the timestamp, only available in the
9609 @code{testsrc} source.
9611 The displayed timestamp value will correspond to the original
9612 timestamp value multiplied by the power of 10 of the specified
9613 value. Default value is 0.
9616 For example the following:
9618 testsrc=duration=5.3:size=qcif:rate=10
9621 will generate a video with a duration of 5.3 seconds, with size
9622 176x144 and a frame rate of 10 frames per second.
9624 The following graph description will generate a red source
9625 with an opacity of 0.2, with size "qcif" and a frame rate of 10
9628 color=c=red@@0.2:s=qcif:r=10
9631 If the input content is to be ignored, @code{nullsrc} can be used. The
9632 following command generates noise in the luminance plane by employing
9633 the @code{geq} filter:
9635 nullsrc=s=256x256, geq=random(1)*255:128:128
9638 @subsection Commands
9640 The @code{color} source supports the following commands:
9644 Set the color of the created image. Accepts the same syntax of the
9645 corresponding @option{color} option.
9648 @c man end VIDEO SOURCES
9650 @chapter Video Sinks
9651 @c man begin VIDEO SINKS
9653 Below is a description of the currently available video sinks.
9657 Buffer video frames, and make them available to the end of the filter
9660 This sink is mainly intended for programmatic use, in particular
9661 through the interface defined in @file{libavfilter/buffersink.h}
9662 or the options system.
9664 It accepts a pointer to an AVBufferSinkContext structure, which
9665 defines the incoming buffers' formats, to be passed as the opaque
9666 parameter to @code{avfilter_init_filter} for initialization.
9670 Null video sink: do absolutely nothing with the input video. It is
9671 mainly useful as a template and for use in analysis / debugging
9674 @c man end VIDEO SINKS
9676 @chapter Multimedia Filters
9677 @c man begin MULTIMEDIA FILTERS
9679 Below is a description of the currently available multimedia filters.
9681 @section avectorscope
9683 Convert input audio to a video output, representing the audio vector
9686 The filter is used to measure the difference between channels of stereo
9687 audio stream. A monoaural signal, consisting of identical left and right
9688 signal, results in straight vertical line. Any stereo separation is visible
9689 as a deviation from this line, creating a Lissajous figure.
9690 If the straight (or deviation from it) but horizontal line appears this
9691 indicates that the left and right channels are out of phase.
9693 The filter accepts the following options:
9697 Set the vectorscope mode.
9699 Available values are:
9702 Lissajous rotated by 45 degrees.
9705 Same as above but not rotated.
9708 Default value is @samp{lissajous}.
9711 Set the video size for the output. For the syntax of this option, check the "Video size"
9712 section in the ffmpeg-utils manual. Default value is @code{400x400}.
9715 Set the output frame rate. Default value is @code{25}.
9720 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
9721 Allowed range is @code{[0, 255]}.
9726 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
9727 Allowed range is @code{[0, 255]}.
9730 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
9733 @subsection Examples
9737 Complete example using @command{ffplay}:
9739 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9740 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
9746 Concatenate audio and video streams, joining them together one after the
9749 The filter works on segments of synchronized video and audio streams. All
9750 segments must have the same number of streams of each type, and that will
9751 also be the number of streams at output.
9753 The filter accepts the following options:
9758 Set the number of segments. Default is 2.
9761 Set the number of output video streams, that is also the number of video
9762 streams in each segment. Default is 1.
9765 Set the number of output audio streams, that is also the number of audio
9766 streams in each segment. Default is 0.
9769 Activate unsafe mode: do not fail if segments have a different format.
9773 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
9774 @var{a} audio outputs.
9776 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
9777 segment, in the same order as the outputs, then the inputs for the second
9780 Related streams do not always have exactly the same duration, for various
9781 reasons including codec frame size or sloppy authoring. For that reason,
9782 related synchronized streams (e.g. a video and its audio track) should be
9783 concatenated at once. The concat filter will use the duration of the longest
9784 stream in each segment (except the last one), and if necessary pad shorter
9785 audio streams with silence.
9787 For this filter to work correctly, all segments must start at timestamp 0.
9789 All corresponding streams must have the same parameters in all segments; the
9790 filtering system will automatically select a common pixel format for video
9791 streams, and a common sample format, sample rate and channel layout for
9792 audio streams, but other settings, such as resolution, must be converted
9793 explicitly by the user.
9795 Different frame rates are acceptable but will result in variable frame rate
9796 at output; be sure to configure the output file to handle it.
9798 @subsection Examples
9802 Concatenate an opening, an episode and an ending, all in bilingual version
9803 (video in stream 0, audio in streams 1 and 2):
9805 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
9806 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
9807 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
9808 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
9812 Concatenate two parts, handling audio and video separately, using the
9813 (a)movie sources, and adjusting the resolution:
9815 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
9816 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
9817 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
9819 Note that a desync will happen at the stitch if the audio and video streams
9820 do not have exactly the same duration in the first file.
9826 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
9827 it unchanged. By default, it logs a message at a frequency of 10Hz with the
9828 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
9829 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
9831 The filter also has a video output (see the @var{video} option) with a real
9832 time graph to observe the loudness evolution. The graphic contains the logged
9833 message mentioned above, so it is not printed anymore when this option is set,
9834 unless the verbose logging is set. The main graphing area contains the
9835 short-term loudness (3 seconds of analysis), and the gauge on the right is for
9836 the momentary loudness (400 milliseconds).
9838 More information about the Loudness Recommendation EBU R128 on
9839 @url{http://tech.ebu.ch/loudness}.
9841 The filter accepts the following options:
9846 Activate the video output. The audio stream is passed unchanged whether this
9847 option is set or no. The video stream will be the first output stream if
9848 activated. Default is @code{0}.
9851 Set the video size. This option is for video only. For the syntax of this
9852 option, check the "Video size" section in the ffmpeg-utils manual. Default
9853 and minimum resolution is @code{640x480}.
9856 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
9857 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
9858 other integer value between this range is allowed.
9861 Set metadata injection. If set to @code{1}, the audio input will be segmented
9862 into 100ms output frames, each of them containing various loudness information
9863 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
9865 Default is @code{0}.
9868 Force the frame logging level.
9870 Available values are:
9873 information logging level
9875 verbose logging level
9878 By default, the logging level is set to @var{info}. If the @option{video} or
9879 the @option{metadata} options are set, it switches to @var{verbose}.
9884 Available modes can be cumulated (the option is a @code{flag} type). Possible
9888 Disable any peak mode (default).
9890 Enable sample-peak mode.
9892 Simple peak mode looking for the higher sample value. It logs a message
9893 for sample-peak (identified by @code{SPK}).
9895 Enable true-peak mode.
9897 If enabled, the peak lookup is done on an over-sampled version of the input
9898 stream for better peak accuracy. It logs a message for true-peak.
9899 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
9900 This mode requires a build with @code{libswresample}.
9905 @subsection Examples
9909 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
9911 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
9915 Run an analysis with @command{ffmpeg}:
9917 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
9921 @section interleave, ainterleave
9923 Temporally interleave frames from several inputs.
9925 @code{interleave} works with video inputs, @code{ainterleave} with audio.
9927 These filters read frames from several inputs and send the oldest
9928 queued frame to the output.
9930 Input streams must have a well defined, monotonically increasing frame
9933 In order to submit one frame to output, these filters need to enqueue
9934 at least one frame for each input, so they cannot work in case one
9935 input is not yet terminated and will not receive incoming frames.
9937 For example consider the case when one input is a @code{select} filter
9938 which always drop input frames. The @code{interleave} filter will keep
9939 reading from that input, but it will never be able to send new frames
9940 to output until the input will send an end-of-stream signal.
9942 Also, depending on inputs synchronization, the filters will drop
9943 frames in case one input receives more frames than the other ones, and
9944 the queue is already filled.
9946 These filters accept the following options:
9950 Set the number of different inputs, it is 2 by default.
9953 @subsection Examples
9957 Interleave frames belonging to different streams using @command{ffmpeg}:
9959 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
9963 Add flickering blur effect:
9965 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
9969 @section perms, aperms
9971 Set read/write permissions for the output frames.
9973 These filters are mainly aimed at developers to test direct path in the
9974 following filter in the filtergraph.
9976 The filters accept the following options:
9980 Select the permissions mode.
9982 It accepts the following values:
9985 Do nothing. This is the default.
9987 Set all the output frames read-only.
9989 Set all the output frames directly writable.
9991 Make the frame read-only if writable, and writable if read-only.
9993 Set each output frame read-only or writable randomly.
9997 Set the seed for the @var{random} mode, must be an integer included between
9998 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
9999 @code{-1}, the filter will try to use a good random seed on a best effort
10003 Note: in case of auto-inserted filter between the permission filter and the
10004 following one, the permission might not be received as expected in that
10005 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
10006 perms/aperms filter can avoid this problem.
10008 @section select, aselect
10010 Select frames to pass in output.
10012 This filter accepts the following options:
10017 Set expression, which is evaluated for each input frame.
10019 If the expression is evaluated to zero, the frame is discarded.
10021 If the evaluation result is negative or NaN, the frame is sent to the
10022 first output; otherwise it is sent to the output with index
10023 @code{ceil(val)-1}, assuming that the input index starts from 0.
10025 For example a value of @code{1.2} corresponds to the output with index
10026 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
10029 Set the number of outputs. The output to which to send the selected
10030 frame is based on the result of the evaluation. Default value is 1.
10033 The expression can contain the following constants:
10037 The (sequential) number of the filtered frame, starting from 0.
10040 The (sequential) number of the selected frame, starting from 0.
10042 @item prev_selected_n
10043 The sequential number of the last selected frame. It's NAN if undefined.
10046 The timebase of the input timestamps.
10049 The PTS (Presentation TimeStamp) of the filtered video frame,
10050 expressed in @var{TB} units. It's NAN if undefined.
10053 The PTS of the filtered video frame,
10054 expressed in seconds. It's NAN if undefined.
10057 The PTS of the previously filtered video frame. It's NAN if undefined.
10059 @item prev_selected_pts
10060 The PTS of the last previously filtered video frame. It's NAN if undefined.
10062 @item prev_selected_t
10063 The PTS of the last previously selected video frame. It's NAN if undefined.
10066 The PTS of the first video frame in the video. It's NAN if undefined.
10069 The time of the first video frame in the video. It's NAN if undefined.
10071 @item pict_type @emph{(video only)}
10072 The type of the filtered frame. It can assume one of the following
10084 @item interlace_type @emph{(video only)}
10085 The frame interlace type. It can assume one of the following values:
10088 The frame is progressive (not interlaced).
10090 The frame is top-field-first.
10092 The frame is bottom-field-first.
10095 @item consumed_sample_n @emph{(audio only)}
10096 the number of selected samples before the current frame
10098 @item samples_n @emph{(audio only)}
10099 the number of samples in the current frame
10101 @item sample_rate @emph{(audio only)}
10102 the input sample rate
10105 This is 1 if the filtered frame is a key-frame, 0 otherwise.
10108 the position in the file of the filtered frame, -1 if the information
10109 is not available (e.g. for synthetic video)
10111 @item scene @emph{(video only)}
10112 value between 0 and 1 to indicate a new scene; a low value reflects a low
10113 probability for the current frame to introduce a new scene, while a higher
10114 value means the current frame is more likely to be one (see the example below)
10118 The default value of the select expression is "1".
10120 @subsection Examples
10124 Select all frames in input:
10129 The example above is the same as:
10141 Select only I-frames:
10143 select='eq(pict_type\,I)'
10147 Select one frame every 100:
10149 select='not(mod(n\,100))'
10153 Select only frames contained in the 10-20 time interval:
10155 select=between(t\,10\,20)
10159 Select only I frames contained in the 10-20 time interval:
10161 select=between(t\,10\,20)*eq(pict_type\,I)
10165 Select frames with a minimum distance of 10 seconds:
10167 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
10171 Use aselect to select only audio frames with samples number > 100:
10173 aselect='gt(samples_n\,100)'
10177 Create a mosaic of the first scenes:
10179 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
10182 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
10186 Send even and odd frames to separate outputs, and compose them:
10188 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
10192 @section sendcmd, asendcmd
10194 Send commands to filters in the filtergraph.
10196 These filters read commands to be sent to other filters in the
10199 @code{sendcmd} must be inserted between two video filters,
10200 @code{asendcmd} must be inserted between two audio filters, but apart
10201 from that they act the same way.
10203 The specification of commands can be provided in the filter arguments
10204 with the @var{commands} option, or in a file specified by the
10205 @var{filename} option.
10207 These filters accept the following options:
10210 Set the commands to be read and sent to the other filters.
10212 Set the filename of the commands to be read and sent to the other
10216 @subsection Commands syntax
10218 A commands description consists of a sequence of interval
10219 specifications, comprising a list of commands to be executed when a
10220 particular event related to that interval occurs. The occurring event
10221 is typically the current frame time entering or leaving a given time
10224 An interval is specified by the following syntax:
10226 @var{START}[-@var{END}] @var{COMMANDS};
10229 The time interval is specified by the @var{START} and @var{END} times.
10230 @var{END} is optional and defaults to the maximum time.
10232 The current frame time is considered within the specified interval if
10233 it is included in the interval [@var{START}, @var{END}), that is when
10234 the time is greater or equal to @var{START} and is lesser than
10237 @var{COMMANDS} consists of a sequence of one or more command
10238 specifications, separated by ",", relating to that interval. The
10239 syntax of a command specification is given by:
10241 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
10244 @var{FLAGS} is optional and specifies the type of events relating to
10245 the time interval which enable sending the specified command, and must
10246 be a non-null sequence of identifier flags separated by "+" or "|" and
10247 enclosed between "[" and "]".
10249 The following flags are recognized:
10252 The command is sent when the current frame timestamp enters the
10253 specified interval. In other words, the command is sent when the
10254 previous frame timestamp was not in the given interval, and the
10258 The command is sent when the current frame timestamp leaves the
10259 specified interval. In other words, the command is sent when the
10260 previous frame timestamp was in the given interval, and the
10264 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
10267 @var{TARGET} specifies the target of the command, usually the name of
10268 the filter class or a specific filter instance name.
10270 @var{COMMAND} specifies the name of the command for the target filter.
10272 @var{ARG} is optional and specifies the optional list of argument for
10273 the given @var{COMMAND}.
10275 Between one interval specification and another, whitespaces, or
10276 sequences of characters starting with @code{#} until the end of line,
10277 are ignored and can be used to annotate comments.
10279 A simplified BNF description of the commands specification syntax
10282 @var{COMMAND_FLAG} ::= "enter" | "leave"
10283 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
10284 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
10285 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
10286 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
10287 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
10290 @subsection Examples
10294 Specify audio tempo change at second 4:
10296 asendcmd=c='4.0 atempo tempo 1.5',atempo
10300 Specify a list of drawtext and hue commands in a file.
10302 # show text in the interval 5-10
10303 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
10304 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
10306 # desaturate the image in the interval 15-20
10307 15.0-20.0 [enter] hue s 0,
10308 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
10310 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
10312 # apply an exponential saturation fade-out effect, starting from time 25
10313 25 [enter] hue s exp(25-t)
10316 A filtergraph allowing to read and process the above command list
10317 stored in a file @file{test.cmd}, can be specified with:
10319 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
10324 @section setpts, asetpts
10326 Change the PTS (presentation timestamp) of the input frames.
10328 @code{setpts} works on video frames, @code{asetpts} on audio frames.
10330 This filter accepts the following options:
10335 The expression which is evaluated for each frame to construct its timestamp.
10339 The expression is evaluated through the eval API and can contain the following
10344 frame rate, only defined for constant frame-rate video
10347 The presentation timestamp in input
10350 The count of the input frame for video or the number of consumed samples,
10351 not including the current frame for audio, starting from 0.
10353 @item NB_CONSUMED_SAMPLES
10354 The number of consumed samples, not including the current frame (only
10357 @item NB_SAMPLES, S
10358 The number of samples in the current frame (only audio)
10360 @item SAMPLE_RATE, SR
10361 The audio sample rate.
10364 The PTS of the first frame.
10367 the time in seconds of the first frame
10370 State whether the current frame is interlaced.
10373 the time in seconds of the current frame
10376 original position in the file of the frame, or undefined if undefined
10377 for the current frame
10380 The previous input PTS.
10383 previous input time in seconds
10386 The previous output PTS.
10389 previous output time in seconds
10392 The wallclock (RTC) time in microseconds.. This is deprecated, use time(0)
10396 The wallclock (RTC) time at the start of the movie in microseconds.
10399 The timebase of the input timestamps.
10403 @subsection Examples
10407 Start counting PTS from zero
10409 setpts=PTS-STARTPTS
10413 Apply fast motion effect:
10419 Apply slow motion effect:
10425 Set fixed rate of 25 frames per second:
10431 Set fixed rate 25 fps with some jitter:
10433 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
10437 Apply an offset of 10 seconds to the input PTS:
10443 Generate timestamps from a "live source" and rebase onto the current timebase:
10445 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
10449 Generate timestamps by counting samples:
10456 @section settb, asettb
10458 Set the timebase to use for the output frames timestamps.
10459 It is mainly useful for testing timebase configuration.
10461 It accepts the following parameters:
10466 The expression which is evaluated into the output timebase.
10470 The value for @option{tb} is an arithmetic expression representing a
10471 rational. The expression can contain the constants "AVTB" (the default
10472 timebase), "intb" (the input timebase) and "sr" (the sample rate,
10473 audio only). Default value is "intb".
10475 @subsection Examples
10479 Set the timebase to 1/25:
10485 Set the timebase to 1/10:
10491 Set the timebase to 1001/1000:
10497 Set the timebase to 2*intb:
10503 Set the default timebase value:
10510 Convert input audio to a video output representing
10511 frequency spectrum logarithmically (using constant Q transform with
10512 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
10514 The filter accepts the following options:
10518 Specify transform volume (multiplier) expression. The expression can contain
10521 @item frequency, freq, f
10522 the frequency where transform is evaluated
10523 @item timeclamp, tc
10524 value of timeclamp option
10528 @item a_weighting(f)
10529 A-weighting of equal loudness
10530 @item b_weighting(f)
10531 B-weighting of equal loudness
10532 @item c_weighting(f)
10533 C-weighting of equal loudness
10535 Default value is @code{16}.
10538 Specify transform length expression. The expression can contain variables:
10540 @item frequency, freq, f
10541 the frequency where transform is evaluated
10542 @item timeclamp, tc
10543 value of timeclamp option
10545 Default value is @code{384/f*tc/(384/f+tc)}.
10548 Specify the transform timeclamp. At low frequency, there is trade-off between
10549 accuracy in time domain and frequency domain. If timeclamp is lower,
10550 event in time domain is represented more accurately (such as fast bass drum),
10551 otherwise event in frequency domain is represented more accurately
10552 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
10555 Specify the transform coeffclamp. If coeffclamp is lower, transform is
10556 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
10557 Default value is @code{1.0}.
10560 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
10561 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
10562 Default value is @code{3.0}.
10565 Specify font file for use with freetype. If not specified, use embedded font.
10568 If set to 1 (the default), the video size is 1920x1080 (full HD),
10569 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
10572 Specify video fps. Default value is @code{25}.
10575 Specify number of transform per frame, so there are fps*count transforms
10576 per second. Note that audio data rate must be divisible by fps*count.
10577 Default value is @code{6}.
10581 @subsection Examples
10585 Playing audio while showing the spectrum:
10587 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
10591 Same as above, but with frame rate 30 fps:
10593 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
10597 Playing at 960x540 and lower CPU usage:
10599 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
10603 A1 and its harmonics: A1, A2, (near)E3, A3:
10605 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),
10606 asplit[a][out1]; [a] showcqt [out0]'
10610 Same as above, but with more accuracy in frequency domain (and slower):
10612 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),
10613 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
10617 B-weighting of equal loudness
10619 volume=16*b_weighting(f)
10625 tlength=100/f*tc/(100/f+tc)
10630 @section showspectrum
10632 Convert input audio to a video output, representing the audio frequency
10635 The filter accepts the following options:
10639 Specify the video size for the output. For the syntax of this option, check
10640 the "Video size" section in the ffmpeg-utils manual. Default value is
10644 Specify if the spectrum should slide along the window. Default value is
10648 Specify display mode.
10650 It accepts the following values:
10653 all channels are displayed in the same row
10655 all channels are displayed in separate rows
10658 Default value is @samp{combined}.
10661 Specify display color mode.
10663 It accepts the following values:
10666 each channel is displayed in a separate color
10668 each channel is is displayed using the same color scheme
10671 Default value is @samp{channel}.
10674 Specify scale used for calculating intensity color values.
10676 It accepts the following values:
10681 square root, default
10688 Default value is @samp{sqrt}.
10691 Set saturation modifier for displayed colors. Negative values provide
10692 alternative color scheme. @code{0} is no saturation at all.
10693 Saturation must be in [-10.0, 10.0] range.
10694 Default value is @code{1}.
10697 Set window function.
10699 It accepts the following values:
10702 No samples pre-processing (do not expect this to be faster)
10711 Default value is @code{hann}.
10714 The usage is very similar to the showwaves filter; see the examples in that
10717 @subsection Examples
10721 Large window with logarithmic color scaling:
10723 showspectrum=s=1280x480:scale=log
10727 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
10729 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10730 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
10736 Convert input audio to a video output, representing the samples waves.
10738 The filter accepts the following options:
10742 Specify the video size for the output. For the syntax of this option, check
10743 the "Video size" section in the ffmpeg-utils manual. Default value
10749 Available values are:
10752 Draw a point for each sample.
10755 Draw a vertical line for each sample.
10758 Draw a point for each sample and a line between them.
10761 Default value is @code{point}.
10764 Set the number of samples which are printed on the same column. A
10765 larger value will decrease the frame rate. Must be a positive
10766 integer. This option can be set only if the value for @var{rate}
10767 is not explicitly specified.
10770 Set the (approximate) output frame rate. This is done by setting the
10771 option @var{n}. Default value is "25".
10775 @subsection Examples
10779 Output the input file audio and the corresponding video representation
10782 amovie=a.mp3,asplit[out0],showwaves[out1]
10786 Create a synthetic signal and show it with showwaves, forcing a
10787 frame rate of 30 frames per second:
10789 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
10793 @section split, asplit
10795 Split input into several identical outputs.
10797 @code{asplit} works with audio input, @code{split} with video.
10799 The filter accepts a single parameter which specifies the number of outputs. If
10800 unspecified, it defaults to 2.
10802 @subsection Examples
10806 Create two separate outputs from the same input:
10808 [in] split [out0][out1]
10812 To create 3 or more outputs, you need to specify the number of
10815 [in] asplit=3 [out0][out1][out2]
10819 Create two separate outputs from the same input, one cropped and
10822 [in] split [splitout1][splitout2];
10823 [splitout1] crop=100:100:0:0 [cropout];
10824 [splitout2] pad=200:200:100:100 [padout];
10828 Create 5 copies of the input audio with @command{ffmpeg}:
10830 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
10836 Receive commands sent through a libzmq client, and forward them to
10837 filters in the filtergraph.
10839 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
10840 must be inserted between two video filters, @code{azmq} between two
10843 To enable these filters you need to install the libzmq library and
10844 headers and configure FFmpeg with @code{--enable-libzmq}.
10846 For more information about libzmq see:
10847 @url{http://www.zeromq.org/}
10849 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
10850 receives messages sent through a network interface defined by the
10851 @option{bind_address} option.
10853 The received message must be in the form:
10855 @var{TARGET} @var{COMMAND} [@var{ARG}]
10858 @var{TARGET} specifies the target of the command, usually the name of
10859 the filter class or a specific filter instance name.
10861 @var{COMMAND} specifies the name of the command for the target filter.
10863 @var{ARG} is optional and specifies the optional argument list for the
10864 given @var{COMMAND}.
10866 Upon reception, the message is processed and the corresponding command
10867 is injected into the filtergraph. Depending on the result, the filter
10868 will send a reply to the client, adopting the format:
10870 @var{ERROR_CODE} @var{ERROR_REASON}
10874 @var{MESSAGE} is optional.
10876 @subsection Examples
10878 Look at @file{tools/zmqsend} for an example of a zmq client which can
10879 be used to send commands processed by these filters.
10881 Consider the following filtergraph generated by @command{ffplay}
10883 ffplay -dumpgraph 1 -f lavfi "
10884 color=s=100x100:c=red [l];
10885 color=s=100x100:c=blue [r];
10886 nullsrc=s=200x100, zmq [bg];
10887 [bg][l] overlay [bg+l];
10888 [bg+l][r] overlay=x=100 "
10891 To change the color of the left side of the video, the following
10892 command can be used:
10894 echo Parsed_color_0 c yellow | tools/zmqsend
10897 To change the right side:
10899 echo Parsed_color_1 c pink | tools/zmqsend
10902 @c man end MULTIMEDIA FILTERS
10904 @chapter Multimedia Sources
10905 @c man begin MULTIMEDIA SOURCES
10907 Below is a description of the currently available multimedia sources.
10911 This is the same as @ref{movie} source, except it selects an audio
10917 Read audio and/or video stream(s) from a movie container.
10919 It accepts the following parameters:
10923 The name of the resource to read (not necessarily a file; it can also be a
10924 device or a stream accessed through some protocol).
10926 @item format_name, f
10927 Specifies the format assumed for the movie to read, and can be either
10928 the name of a container or an input device. If not specified, the
10929 format is guessed from @var{movie_name} or by probing.
10931 @item seek_point, sp
10932 Specifies the seek point in seconds. The frames will be output
10933 starting from this seek point. The parameter is evaluated with
10934 @code{av_strtod}, so the numerical value may be suffixed by an IS
10935 postfix. The default value is "0".
10938 Specifies the streams to read. Several streams can be specified,
10939 separated by "+". The source will then have as many outputs, in the
10940 same order. The syntax is explained in the ``Stream specifiers''
10941 section in the ffmpeg manual. Two special names, "dv" and "da" specify
10942 respectively the default (best suited) video and audio stream. Default
10943 is "dv", or "da" if the filter is called as "amovie".
10945 @item stream_index, si
10946 Specifies the index of the video stream to read. If the value is -1,
10947 the most suitable video stream will be automatically selected. The default
10948 value is "-1". Deprecated. If the filter is called "amovie", it will select
10949 audio instead of video.
10952 Specifies how many times to read the stream in sequence.
10953 If the value is less than 1, the stream will be read again and again.
10954 Default value is "1".
10956 Note that when the movie is looped the source timestamps are not
10957 changed, so it will generate non monotonically increasing timestamps.
10960 It allows overlaying a second video on top of the main input of
10961 a filtergraph, as shown in this graph:
10963 input -----------> deltapts0 --> overlay --> output
10966 movie --> scale--> deltapts1 -------+
10968 @subsection Examples
10972 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
10973 on top of the input labelled "in":
10975 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
10976 [in] setpts=PTS-STARTPTS [main];
10977 [main][over] overlay=16:16 [out]
10981 Read from a video4linux2 device, and overlay it on top of the input
10984 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
10985 [in] setpts=PTS-STARTPTS [main];
10986 [main][over] overlay=16:16 [out]
10990 Read the first video stream and the audio stream with id 0x81 from
10991 dvd.vob; the video is connected to the pad named "video" and the audio is
10992 connected to the pad named "audio":
10994 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
10998 @c man end MULTIMEDIA SOURCES