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 recognized by the
118 @option{-filter}/@option{-vf}/@option{-af} and
119 @option{-filter_complex} options in @command{ffmpeg} and
120 @option{-vf}/@option{-af} in @command{ffplay}, and by the
121 @code{avfilter_graph_parse_ptr()} function defined in
122 @file{libavfilter/avfilter.h}.
124 A filterchain consists of a sequence of connected filters, each one
125 connected to the previous one in the sequence. A filterchain is
126 represented by a list of ","-separated filter descriptions.
128 A filtergraph consists of a sequence of filterchains. A sequence of
129 filterchains is represented by a list of ";"-separated filterchain
132 A filter is represented by a string of the form:
133 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
135 @var{filter_name} is the name of the filter class of which the
136 described filter is an instance of, and has to be the name of one of
137 the filter classes registered in the program.
138 The name of the filter class is optionally followed by a string
141 @var{arguments} is a string which contains the parameters used to
142 initialize the filter instance. It may have one of two forms:
146 A ':'-separated list of @var{key=value} pairs.
149 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
150 the option names in the order they are declared. E.g. the @code{fade} filter
151 declares three options in this order -- @option{type}, @option{start_frame} and
152 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
153 @var{in} is assigned to the option @option{type}, @var{0} to
154 @option{start_frame} and @var{30} to @option{nb_frames}.
157 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
158 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
159 follow the same constraints order of the previous point. The following
160 @var{key=value} pairs can be set in any preferred order.
164 If the option value itself is a list of items (e.g. the @code{format} filter
165 takes a list of pixel formats), the items in the list are usually separated by
168 The list of arguments can be quoted using the character "'" as initial
169 and ending mark, and the character '\' for escaping the characters
170 within the quoted text; otherwise the argument string is considered
171 terminated when the next special character (belonging to the set
172 "[]=;,") is encountered.
174 The name and arguments of the filter are optionally preceded and
175 followed by a list of link labels.
176 A link label allows one to name a link and associate it to a filter output
177 or input pad. The preceding labels @var{in_link_1}
178 ... @var{in_link_N}, are associated to the filter input pads,
179 the following labels @var{out_link_1} ... @var{out_link_M}, are
180 associated to the output pads.
182 When two link labels with the same name are found in the
183 filtergraph, a link between the corresponding input and output pad is
186 If an output pad is not labelled, it is linked by default to the first
187 unlabelled input pad of the next filter in the filterchain.
188 For example in the filterchain
190 nullsrc, split[L1], [L2]overlay, nullsink
192 the split filter instance has two output pads, and the overlay filter
193 instance two input pads. The first output pad of split is labelled
194 "L1", the first input pad of overlay is labelled "L2", and the second
195 output pad of split is linked to the second input pad of overlay,
196 which are both unlabelled.
198 In a filter description, if the input label of the first filter is not
199 specified, "in" is assumed; if the output label of the last filter is not
200 specified, "out" is assumed.
202 In a complete filterchain all the unlabelled filter input and output
203 pads must be connected. A filtergraph is considered valid if all the
204 filter input and output pads of all the filterchains are connected.
206 Libavfilter will automatically insert @ref{scale} filters where format
207 conversion is required. It is possible to specify swscale flags
208 for those automatically inserted scalers by prepending
209 @code{sws_flags=@var{flags};}
210 to the filtergraph description.
212 Here is a BNF description of the filtergraph syntax:
214 @var{NAME} ::= sequence of alphanumeric characters and '_'
215 @var{LINKLABEL} ::= "[" @var{NAME} "]"
216 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
217 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
218 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
219 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
220 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
223 @section Notes on filtergraph escaping
225 Filtergraph description composition entails several levels of
226 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
227 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
228 information about the employed escaping procedure.
230 A first level escaping affects the content of each filter option
231 value, which may contain the special character @code{:} used to
232 separate values, or one of the escaping characters @code{\'}.
234 A second level escaping affects the whole filter description, which
235 may contain the escaping characters @code{\'} or the special
236 characters @code{[],;} used by the filtergraph description.
238 Finally, when you specify a filtergraph on a shell commandline, you
239 need to perform a third level escaping for the shell special
240 characters contained within it.
242 For example, consider the following string to be embedded in
243 the @ref{drawtext} filter description @option{text} value:
245 this is a 'string': may contain one, or more, special characters
248 This string contains the @code{'} special escaping character, and the
249 @code{:} special character, so it needs to be escaped in this way:
251 text=this is a \'string\'\: may contain one, or more, special characters
254 A second level of escaping is required when embedding the filter
255 description in a filtergraph description, in order to escape all the
256 filtergraph special characters. Thus the example above becomes:
258 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
260 (note that in addition to the @code{\'} escaping special characters,
261 also @code{,} needs to be escaped).
263 Finally an additional level of escaping is needed when writing the
264 filtergraph description in a shell command, which depends on the
265 escaping rules of the adopted shell. For example, assuming that
266 @code{\} is special and needs to be escaped with another @code{\}, the
267 previous string will finally result in:
269 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
272 @chapter Timeline editing
274 Some filters support a generic @option{enable} option. For the filters
275 supporting timeline editing, this option can be set to an expression which is
276 evaluated before sending a frame to the filter. If the evaluation is non-zero,
277 the filter will be enabled, otherwise the frame will be sent unchanged to the
278 next filter in the filtergraph.
280 The expression accepts the following values:
283 timestamp expressed in seconds, NAN if the input timestamp is unknown
286 sequential number of the input frame, starting from 0
289 the position in the file of the input frame, NAN if unknown
293 width and height of the input frame if video
296 Additionally, these filters support an @option{enable} command that can be used
297 to re-define the expression.
299 Like any other filtering option, the @option{enable} option follows the same
302 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
303 minutes, and a @ref{curves} filter starting at 3 seconds:
305 smartblur = enable='between(t,10,3*60)',
306 curves = enable='gte(t,3)' : preset=cross_process
309 @c man end FILTERGRAPH DESCRIPTION
311 @chapter Audio Filters
312 @c man begin AUDIO FILTERS
314 When you configure your FFmpeg build, you can disable any of the
315 existing filters using @code{--disable-filters}.
316 The configure output will show the audio filters included in your
319 Below is a description of the currently available audio filters.
323 Delay one or more audio channels.
325 Samples in delayed channel are filled with silence.
327 The filter accepts the following option:
331 Set list of delays in milliseconds for each channel separated by '|'.
332 At least one delay greater than 0 should be provided.
333 Unused delays will be silently ignored. If number of given delays is
334 smaller than number of channels all remaining channels will not be delayed.
341 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
342 the second channel (and any other channels that may be present) unchanged.
350 Apply echoing to the input audio.
352 Echoes are reflected sound and can occur naturally amongst mountains
353 (and sometimes large buildings) when talking or shouting; digital echo
354 effects emulate this behaviour and are often used to help fill out the
355 sound of a single instrument or vocal. The time difference between the
356 original signal and the reflection is the @code{delay}, and the
357 loudness of the reflected signal is the @code{decay}.
358 Multiple echoes can have different delays and decays.
360 A description of the accepted parameters follows.
364 Set input gain of reflected signal. Default is @code{0.6}.
367 Set output gain of reflected signal. Default is @code{0.3}.
370 Set list of time intervals in milliseconds between original signal and reflections
371 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
372 Default is @code{1000}.
375 Set list of loudnesses of reflected signals separated by '|'.
376 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
377 Default is @code{0.5}.
384 Make it sound as if there are twice as many instruments as are actually playing:
386 aecho=0.8:0.88:60:0.4
390 If delay is very short, then it sound like a (metallic) robot playing music:
396 A longer delay will sound like an open air concert in the mountains:
398 aecho=0.8:0.9:1000:0.3
402 Same as above but with one more mountain:
404 aecho=0.8:0.9:1000|1800:0.3|0.25
410 Modify an audio signal according to the specified expressions.
412 This filter accepts one or more expressions (one for each channel),
413 which are evaluated and used to modify a corresponding audio signal.
415 It accepts the following parameters:
419 Set the '|'-separated expressions list for each separate channel. If
420 the number of input channels is greater than the number of
421 expressions, the last specified expression is used for the remaining
424 @item channel_layout, c
425 Set output channel layout. If not specified, the channel layout is
426 specified by the number of expressions. If set to @samp{same}, it will
427 use by default the same input channel layout.
430 Each expression in @var{exprs} can contain the following constants and functions:
434 channel number of the current expression
437 number of the evaluated sample, starting from 0
443 time of the evaluated sample expressed in seconds
446 @item nb_out_channels
447 input and output number of channels
450 the value of input channel with number @var{CH}
453 Note: this filter is slow. For faster processing you should use a
462 aeval=val(ch)/2:c=same
466 Invert phase of the second channel:
474 Apply fade-in/out effect to input audio.
476 A description of the accepted parameters follows.
480 Specify the effect type, can be either @code{in} for fade-in, or
481 @code{out} for a fade-out effect. Default is @code{in}.
483 @item start_sample, ss
484 Specify the number of the start sample for starting to apply the fade
485 effect. Default is 0.
488 Specify the number of samples for which the fade effect has to last. At
489 the end of the fade-in effect the output audio will have the same
490 volume as the input audio, at the end of the fade-out transition
491 the output audio will be silence. Default is 44100.
494 Specify the start time of the fade effect. Default is 0.
495 The value must be specified as a time duration; see
496 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
497 for the accepted syntax.
498 If set this option is used instead of @var{start_sample}.
501 Specify the duration of the fade effect. See
502 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
503 for the accepted syntax.
504 At the end of the fade-in effect the output audio will have the same
505 volume as the input audio, at the end of the fade-out transition
506 the output audio will be silence.
507 By default the duration is determined by @var{nb_samples}.
508 If set this option is used instead of @var{nb_samples}.
511 Set curve for fade transition.
513 It accepts the following values:
516 select triangular, linear slope (default)
518 select quarter of sine wave
520 select half of sine wave
522 select exponential sine wave
526 select inverted parabola
542 Fade in first 15 seconds of audio:
548 Fade out last 25 seconds of a 900 seconds audio:
550 afade=t=out:st=875:d=25
557 Set output format constraints for the input audio. The framework will
558 negotiate the most appropriate format to minimize conversions.
560 It accepts the following parameters:
564 A '|'-separated list of requested sample formats.
567 A '|'-separated list of requested sample rates.
569 @item channel_layouts
570 A '|'-separated list of requested channel layouts.
572 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
573 for the required syntax.
576 If a parameter is omitted, all values are allowed.
578 Force the output to either unsigned 8-bit or signed 16-bit stereo
580 aformat=sample_fmts=u8|s16:channel_layouts=stereo
585 Apply a two-pole all-pass filter with central frequency (in Hz)
586 @var{frequency}, and filter-width @var{width}.
587 An all-pass filter changes the audio's frequency to phase relationship
588 without changing its frequency to amplitude relationship.
590 The filter accepts the following options:
597 Set method to specify band-width of filter.
610 Specify the band-width of a filter in width_type units.
615 Merge two or more audio streams into a single multi-channel stream.
617 The filter accepts the following options:
622 Set the number of inputs. Default is 2.
626 If the channel layouts of the inputs are disjoint, and therefore compatible,
627 the channel layout of the output will be set accordingly and the channels
628 will be reordered as necessary. If the channel layouts of the inputs are not
629 disjoint, the output will have all the channels of the first input then all
630 the channels of the second input, in that order, and the channel layout of
631 the output will be the default value corresponding to the total number of
634 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
635 is FC+BL+BR, then the output will be in 5.1, with the channels in the
636 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
637 first input, b1 is the first channel of the second input).
639 On the other hand, if both input are in stereo, the output channels will be
640 in the default order: a1, a2, b1, b2, and the channel layout will be
641 arbitrarily set to 4.0, which may or may not be the expected value.
643 All inputs must have the same sample rate, and format.
645 If inputs do not have the same duration, the output will stop with the
652 Merge two mono files into a stereo stream:
654 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
658 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
660 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
666 Mixes multiple audio inputs into a single output.
668 Note that this filter only supports float samples (the @var{amerge}
669 and @var{pan} audio filters support many formats). If the @var{amix}
670 input has integer samples then @ref{aresample} will be automatically
671 inserted to perform the conversion to float samples.
675 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
677 will mix 3 input audio streams to a single output with the same duration as the
678 first input and a dropout transition time of 3 seconds.
680 It accepts the following parameters:
684 The number of inputs. If unspecified, it defaults to 2.
687 How to determine the end-of-stream.
691 The duration of the longest input. (default)
694 The duration of the shortest input.
697 The duration of the first input.
701 @item dropout_transition
702 The transition time, in seconds, for volume renormalization when an input
703 stream ends. The default value is 2 seconds.
709 Pass the audio source unchanged to the output.
713 Pad the end of an audio stream with silence.
715 This can be used together with @command{ffmpeg} @option{-shortest} to
716 extend audio streams to the same length as the video stream.
718 A description of the accepted options follows.
722 Set silence packet size. Default value is 4096.
725 Set the number of samples of silence to add to the end. After the
726 value is reached, the stream is terminated. This option is mutually
727 exclusive with @option{whole_len}.
730 Set the minimum total number of samples in the output audio stream. If
731 the value is longer than the input audio length, silence is added to
732 the end, until the value is reached. This option is mutually exclusive
733 with @option{pad_len}.
736 If neither the @option{pad_len} nor the @option{whole_len} option is
737 set, the filter will add silence to the end of the input stream
744 Add 1024 samples of silence to the end of the input:
750 Make sure the audio output will contain at least 10000 samples, pad
751 the input with silence if required:
757 Use @command{ffmpeg} to pad the audio input with silence, so that the
758 video stream will always result the shortest and will be converted
759 until the end in the output file when using the @option{shortest}
762 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
767 Add a phasing effect to the input audio.
769 A phaser filter creates series of peaks and troughs in the frequency spectrum.
770 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
772 A description of the accepted parameters follows.
776 Set input gain. Default is 0.4.
779 Set output gain. Default is 0.74
782 Set delay in milliseconds. Default is 3.0.
785 Set decay. Default is 0.4.
788 Set modulation speed in Hz. Default is 0.5.
791 Set modulation type. Default is triangular.
793 It accepts the following values:
803 Resample the input audio to the specified parameters, using the
804 libswresample library. If none are specified then the filter will
805 automatically convert between its input and output.
807 This filter is also able to stretch/squeeze the audio data to make it match
808 the timestamps or to inject silence / cut out audio to make it match the
809 timestamps, do a combination of both or do neither.
811 The filter accepts the syntax
812 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
813 expresses a sample rate and @var{resampler_options} is a list of
814 @var{key}=@var{value} pairs, separated by ":". See the
815 ffmpeg-resampler manual for the complete list of supported options.
821 Resample the input audio to 44100Hz:
827 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
828 samples per second compensation:
834 @section asetnsamples
836 Set the number of samples per each output audio frame.
838 The last output packet may contain a different number of samples, as
839 the filter will flush all the remaining samples when the input audio
842 The filter accepts the following options:
846 @item nb_out_samples, n
847 Set the number of frames per each output audio frame. The number is
848 intended as the number of samples @emph{per each channel}.
849 Default value is 1024.
852 If set to 1, the filter will pad the last audio frame with zeroes, so
853 that the last frame will contain the same number of samples as the
854 previous ones. Default value is 1.
857 For example, to set the number of per-frame samples to 1234 and
858 disable padding for the last frame, use:
860 asetnsamples=n=1234:p=0
865 Set the sample rate without altering the PCM data.
866 This will result in a change of speed and pitch.
868 The filter accepts the following options:
872 Set the output sample rate. Default is 44100 Hz.
877 Show a line containing various information for each input audio frame.
878 The input audio is not modified.
880 The shown line contains a sequence of key/value pairs of the form
881 @var{key}:@var{value}.
883 The following values are shown in the output:
887 The (sequential) number of the input frame, starting from 0.
890 The presentation timestamp of the input frame, in time base units; the time base
891 depends on the filter input pad, and is usually 1/@var{sample_rate}.
894 The presentation timestamp of the input frame in seconds.
897 position of the frame in the input stream, -1 if this information in
898 unavailable and/or meaningless (for example in case of synthetic audio)
907 The sample rate for the audio frame.
910 The number of samples (per channel) in the frame.
913 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
914 audio, the data is treated as if all the planes were concatenated.
916 @item plane_checksums
917 A list of Adler-32 checksums for each data plane.
922 Display time domain statistical information about the audio channels.
923 Statistics are calculated and displayed for each audio channel and,
924 where applicable, an overall figure is also given.
926 It accepts the following option:
929 Short window length in seconds, used for peak and trough RMS measurement.
930 Default is @code{0.05} (50 milliseconds). Allowed range is @code{[0.1 - 10]}.
933 A description of each shown parameter follows:
937 Mean amplitude displacement from zero.
940 Minimal sample level.
943 Maximal sample level.
947 Standard peak and RMS level measured in dBFS.
951 Peak and trough values for RMS level measured over a short window.
954 Standard ratio of peak to RMS level (note: not in dB).
957 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
958 (i.e. either @var{Min level} or @var{Max level}).
961 Number of occasions (not the number of samples) that the signal attained either
962 @var{Min level} or @var{Max level}.
967 Forward two audio streams and control the order the buffers are forwarded.
969 The filter accepts the following options:
973 Set the expression deciding which stream should be
974 forwarded next: if the result is negative, the first stream is forwarded; if
975 the result is positive or zero, the second stream is forwarded. It can use
976 the following variables:
980 number of buffers forwarded so far on each stream
982 number of samples forwarded so far on each stream
984 current timestamp of each stream
987 The default value is @code{t1-t2}, which means to always forward the stream
988 that has a smaller timestamp.
993 Stress-test @code{amerge} by randomly sending buffers on the wrong
994 input, while avoiding too much of a desynchronization:
996 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
997 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
1003 Synchronize audio data with timestamps by squeezing/stretching it and/or
1004 dropping samples/adding silence when needed.
1006 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1008 It accepts the following parameters:
1012 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1013 by default. When disabled, time gaps are covered with silence.
1016 The minimum difference between timestamps and audio data (in seconds) to trigger
1017 adding/dropping samples. The default value is 0.1. If you get an imperfect
1018 sync with this filter, try setting this parameter to 0.
1021 The maximum compensation in samples per second. Only relevant with compensate=1.
1022 The default value is 500.
1025 Assume that the first PTS should be this value. The time base is 1 / sample
1026 rate. This allows for padding/trimming at the start of the stream. By default,
1027 no assumption is made about the first frame's expected PTS, so no padding or
1028 trimming is done. For example, this could be set to 0 to pad the beginning with
1029 silence if an audio stream starts after the video stream or to trim any samples
1030 with a negative PTS due to encoder delay.
1038 The filter accepts exactly one parameter, the audio tempo. If not
1039 specified then the filter will assume nominal 1.0 tempo. Tempo must
1040 be in the [0.5, 2.0] range.
1042 @subsection Examples
1046 Slow down audio to 80% tempo:
1052 To speed up audio to 125% tempo:
1060 Trim the input so that the output contains one continuous subpart of the input.
1062 It accepts the following parameters:
1065 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1066 sample with the timestamp @var{start} will be the first sample in the output.
1069 Specify time of the first audio sample that will be dropped, i.e. the
1070 audio sample immediately preceding the one with the timestamp @var{end} will be
1071 the last sample in the output.
1074 Same as @var{start}, except this option sets the start timestamp in samples
1078 Same as @var{end}, except this option sets the end timestamp in samples instead
1082 The maximum duration of the output in seconds.
1085 The number of the first sample that should be output.
1088 The number of the first sample that should be dropped.
1091 @option{start}, @option{end}, and @option{duration} are expressed as time
1092 duration specifications; see
1093 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
1095 Note that the first two sets of the start/end options and the @option{duration}
1096 option look at the frame timestamp, while the _sample options simply count the
1097 samples that pass through the filter. So start/end_pts and start/end_sample will
1098 give different results when the timestamps are wrong, inexact or do not start at
1099 zero. Also note that this filter does not modify the timestamps. If you wish
1100 to have the output timestamps start at zero, insert the asetpts filter after the
1103 If multiple start or end options are set, this filter tries to be greedy and
1104 keep all samples that match at least one of the specified constraints. To keep
1105 only the part that matches all the constraints at once, chain multiple atrim
1108 The defaults are such that all the input is kept. So it is possible to set e.g.
1109 just the end values to keep everything before the specified time.
1114 Drop everything except the second minute of input:
1116 ffmpeg -i INPUT -af atrim=60:120
1120 Keep only the first 1000 samples:
1122 ffmpeg -i INPUT -af atrim=end_sample=1000
1129 Apply a two-pole Butterworth band-pass filter with central
1130 frequency @var{frequency}, and (3dB-point) band-width width.
1131 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1132 instead of the default: constant 0dB peak gain.
1133 The filter roll off at 6dB per octave (20dB per decade).
1135 The filter accepts the following options:
1139 Set the filter's central frequency. Default is @code{3000}.
1142 Constant skirt gain if set to 1. Defaults to 0.
1145 Set method to specify band-width of filter.
1158 Specify the band-width of a filter in width_type units.
1163 Apply a two-pole Butterworth band-reject filter with central
1164 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1165 The filter roll off at 6dB per octave (20dB per decade).
1167 The filter accepts the following options:
1171 Set the filter's central frequency. Default is @code{3000}.
1174 Set method to specify band-width of filter.
1187 Specify the band-width of a filter in width_type units.
1192 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1193 shelving filter with a response similar to that of a standard
1194 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1196 The filter accepts the following options:
1200 Give the gain at 0 Hz. Its useful range is about -20
1201 (for a large cut) to +20 (for a large boost).
1202 Beware of clipping when using a positive gain.
1205 Set the filter's central frequency and so can be used
1206 to extend or reduce the frequency range to be boosted or cut.
1207 The default value is @code{100} Hz.
1210 Set method to specify band-width of filter.
1223 Determine how steep is the filter's shelf transition.
1228 Apply a biquad IIR filter with the given coefficients.
1229 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1230 are the numerator and denominator coefficients respectively.
1233 Bauer stereo to binaural transformation, which improves headphone listening of
1234 stereo audio records.
1236 It accepts the following parameters:
1240 Pre-defined crossfeed level.
1244 Default level (fcut=700, feed=50).
1247 Chu Moy circuit (fcut=700, feed=60).
1250 Jan Meier circuit (fcut=650, feed=95).
1255 Cut frequency (in Hz).
1264 Remap input channels to new locations.
1266 It accepts the following parameters:
1268 @item channel_layout
1269 The channel layout of the output stream.
1272 Map channels from input to output. The argument is a '|'-separated list of
1273 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1274 @var{in_channel} form. @var{in_channel} can be either the name of the input
1275 channel (e.g. FL for front left) or its index in the input channel layout.
1276 @var{out_channel} is the name of the output channel or its index in the output
1277 channel layout. If @var{out_channel} is not given then it is implicitly an
1278 index, starting with zero and increasing by one for each mapping.
1281 If no mapping is present, the filter will implicitly map input channels to
1282 output channels, preserving indices.
1284 For example, assuming a 5.1+downmix input MOV file,
1286 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1288 will create an output WAV file tagged as stereo from the downmix channels of
1291 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1293 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1296 @section channelsplit
1298 Split each channel from an input audio stream into a separate output stream.
1300 It accepts the following parameters:
1302 @item channel_layout
1303 The channel layout of the input stream. The default is "stereo".
1306 For example, assuming a stereo input MP3 file,
1308 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1310 will create an output Matroska file with two audio streams, one containing only
1311 the left channel and the other the right channel.
1313 Split a 5.1 WAV file into per-channel files:
1315 ffmpeg -i in.wav -filter_complex
1316 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1317 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1318 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1323 Compress or expand the audio's dynamic range.
1325 It accepts the following parameters:
1331 A list of times in seconds for each channel over which the instantaneous level
1332 of the input signal is averaged to determine its volume. @var{attacks} refers to
1333 increase of volume and @var{decays} refers to decrease of volume. For most
1334 situations, the attack time (response to the audio getting louder) should be
1335 shorter than the decay time, because the human ear is more sensitive to sudden
1336 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1337 a typical value for decay is 0.8 seconds.
1340 A list of points for the transfer function, specified in dB relative to the
1341 maximum possible signal amplitude. Each key points list must be defined using
1342 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1343 @code{x0/y0 x1/y1 x2/y2 ....}
1345 The input values must be in strictly increasing order but the transfer function
1346 does not have to be monotonically rising. The point @code{0/0} is assumed but
1347 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1348 function are @code{-70/-70|-60/-20}.
1351 Set the curve radius in dB for all joints. It defaults to 0.01.
1354 Set the additional gain in dB to be applied at all points on the transfer
1355 function. This allows for easy adjustment of the overall gain.
1359 Set an initial volume, in dB, to be assumed for each channel when filtering
1360 starts. This permits the user to supply a nominal level initially, so that, for
1361 example, a very large gain is not applied to initial signal levels before the
1362 companding has begun to operate. A typical value for audio which is initially
1363 quiet is -90 dB. It defaults to 0.
1366 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1367 delayed before being fed to the volume adjuster. Specifying a delay
1368 approximately equal to the attack/decay times allows the filter to effectively
1369 operate in predictive rather than reactive mode. It defaults to 0.
1373 @subsection Examples
1377 Make music with both quiet and loud passages suitable for listening to in a
1380 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1384 A noise gate for when the noise is at a lower level than the signal:
1386 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1390 Here is another noise gate, this time for when the noise is at a higher level
1391 than the signal (making it, in some ways, similar to squelch):
1393 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1399 Make audio easier to listen to on headphones.
1401 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1402 so that when listened to on headphones the stereo image is moved from
1403 inside your head (standard for headphones) to outside and in front of
1404 the listener (standard for speakers).
1410 Apply a two-pole peaking equalisation (EQ) filter. With this
1411 filter, the signal-level at and around a selected frequency can
1412 be increased or decreased, whilst (unlike bandpass and bandreject
1413 filters) that at all other frequencies is unchanged.
1415 In order to produce complex equalisation curves, this filter can
1416 be given several times, each with a different central frequency.
1418 The filter accepts the following options:
1422 Set the filter's central frequency in Hz.
1425 Set method to specify band-width of filter.
1438 Specify the band-width of a filter in width_type units.
1441 Set the required gain or attenuation in dB.
1442 Beware of clipping when using a positive gain.
1445 @subsection Examples
1448 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1450 equalizer=f=1000:width_type=h:width=200:g=-10
1454 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1456 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1461 Apply a flanging effect to the audio.
1463 The filter accepts the following options:
1467 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
1470 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
1473 Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
1477 Set percentage of delayed signal mixed with original. Range from 0 to 100.
1478 Default value is 71.
1481 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
1484 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
1485 Default value is @var{sinusoidal}.
1488 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
1489 Default value is 25.
1492 Set delay-line interpolation, @var{linear} or @var{quadratic}.
1493 Default is @var{linear}.
1498 Apply a high-pass filter with 3dB point frequency.
1499 The filter can be either single-pole, or double-pole (the default).
1500 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1502 The filter accepts the following options:
1506 Set frequency in Hz. Default is 3000.
1509 Set number of poles. Default is 2.
1512 Set method to specify band-width of filter.
1525 Specify the band-width of a filter in width_type units.
1526 Applies only to double-pole filter.
1527 The default is 0.707q and gives a Butterworth response.
1532 Join multiple input streams into one multi-channel stream.
1534 It accepts the following parameters:
1538 The number of input streams. It defaults to 2.
1540 @item channel_layout
1541 The desired output channel layout. It defaults to stereo.
1544 Map channels from inputs to output. The argument is a '|'-separated list of
1545 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1546 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1547 can be either the name of the input channel (e.g. FL for front left) or its
1548 index in the specified input stream. @var{out_channel} is the name of the output
1552 The filter will attempt to guess the mappings when they are not specified
1553 explicitly. It does so by first trying to find an unused matching input channel
1554 and if that fails it picks the first unused input channel.
1556 Join 3 inputs (with properly set channel layouts):
1558 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1561 Build a 5.1 output from 6 single-channel streams:
1563 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1564 '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'
1570 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1572 To enable compilation of this filter you need to configure FFmpeg with
1573 @code{--enable-ladspa}.
1577 Specifies the name of LADSPA plugin library to load. If the environment
1578 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1579 each one of the directories specified by the colon separated list in
1580 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1581 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1582 @file{/usr/lib/ladspa/}.
1585 Specifies the plugin within the library. Some libraries contain only
1586 one plugin, but others contain many of them. If this is not set filter
1587 will list all available plugins within the specified library.
1590 Set the '|' separated list of controls which are zero or more floating point
1591 values that determine the behavior of the loaded plugin (for example delay,
1593 Controls need to be defined using the following syntax:
1594 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1595 @var{valuei} is the value set on the @var{i}-th control.
1596 If @option{controls} is set to @code{help}, all available controls and
1597 their valid ranges are printed.
1599 @item sample_rate, s
1600 Specify the sample rate, default to 44100. Only used if plugin have
1604 Set the number of samples per channel per each output frame, default
1605 is 1024. Only used if plugin have zero inputs.
1608 Set the minimum duration of the sourced audio. See
1609 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
1610 for the accepted syntax.
1611 Note that the resulting duration may be greater than the specified duration,
1612 as the generated audio is always cut at the end of a complete frame.
1613 If not specified, or the expressed duration is negative, the audio is
1614 supposed to be generated forever.
1615 Only used if plugin have zero inputs.
1619 @subsection Examples
1623 List all available plugins within amp (LADSPA example plugin) library:
1629 List all available controls and their valid ranges for @code{vcf_notch}
1630 plugin from @code{VCF} library:
1632 ladspa=f=vcf:p=vcf_notch:c=help
1636 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1639 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1643 Add reverberation to the audio using TAP-plugins
1644 (Tom's Audio Processing plugins):
1646 ladspa=file=tap_reverb:tap_reverb
1650 Generate white noise, with 0.2 amplitude:
1652 ladspa=file=cmt:noise_source_white:c=c0=.2
1656 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1657 @code{C* Audio Plugin Suite} (CAPS) library:
1659 ladspa=file=caps:Click:c=c1=20'
1663 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1665 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1669 @subsection Commands
1671 This filter supports the following commands:
1674 Modify the @var{N}-th control value.
1676 If the specified value is not valid, it is ignored and prior one is kept.
1681 Apply a low-pass filter with 3dB point frequency.
1682 The filter can be either single-pole or double-pole (the default).
1683 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1685 The filter accepts the following options:
1689 Set frequency in Hz. Default is 500.
1692 Set number of poles. Default is 2.
1695 Set method to specify band-width of filter.
1708 Specify the band-width of a filter in width_type units.
1709 Applies only to double-pole filter.
1710 The default is 0.707q and gives a Butterworth response.
1715 Mix channels with specific gain levels. The filter accepts the output
1716 channel layout followed by a set of channels definitions.
1718 This filter is also designed to efficiently remap the channels of an audio
1721 The filter accepts parameters of the form:
1722 "@var{l}|@var{outdef}|@var{outdef}|..."
1726 output channel layout or number of channels
1729 output channel specification, of the form:
1730 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1733 output channel to define, either a channel name (FL, FR, etc.) or a channel
1734 number (c0, c1, etc.)
1737 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1740 input channel to use, see out_name for details; it is not possible to mix
1741 named and numbered input channels
1744 If the `=' in a channel specification is replaced by `<', then the gains for
1745 that specification will be renormalized so that the total is 1, thus
1746 avoiding clipping noise.
1748 @subsection Mixing examples
1750 For example, if you want to down-mix from stereo to mono, but with a bigger
1751 factor for the left channel:
1753 pan=1c|c0=0.9*c0+0.1*c1
1756 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1757 7-channels surround:
1759 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1762 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1763 that should be preferred (see "-ac" option) unless you have very specific
1766 @subsection Remapping examples
1768 The channel remapping will be effective if, and only if:
1771 @item gain coefficients are zeroes or ones,
1772 @item only one input per channel output,
1775 If all these conditions are satisfied, the filter will notify the user ("Pure
1776 channel mapping detected"), and use an optimized and lossless method to do the
1779 For example, if you have a 5.1 source and want a stereo audio stream by
1780 dropping the extra channels:
1782 pan="stereo| c0=FL | c1=FR"
1785 Given the same source, you can also switch front left and front right channels
1786 and keep the input channel layout:
1788 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
1791 If the input is a stereo audio stream, you can mute the front left channel (and
1792 still keep the stereo channel layout) with:
1797 Still with a stereo audio stream input, you can copy the right channel in both
1798 front left and right:
1800 pan="stereo| c0=FR | c1=FR"
1805 ReplayGain scanner filter. This filter takes an audio stream as an input and
1806 outputs it unchanged.
1807 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1811 Convert the audio sample format, sample rate and channel layout. It is
1812 not meant to be used directly.
1814 @section silencedetect
1816 Detect silence in an audio stream.
1818 This filter logs a message when it detects that the input audio volume is less
1819 or equal to a noise tolerance value for a duration greater or equal to the
1820 minimum detected noise duration.
1822 The printed times and duration are expressed in seconds.
1824 The filter accepts the following options:
1828 Set silence duration until notification (default is 2 seconds).
1831 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1832 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1835 @subsection Examples
1839 Detect 5 seconds of silence with -50dB noise tolerance:
1841 silencedetect=n=-50dB:d=5
1845 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1846 tolerance in @file{silence.mp3}:
1848 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1852 @section silenceremove
1854 Remove silence from the beginning, middle or end of the audio.
1856 The filter accepts the following options:
1860 This value is used to indicate if audio should be trimmed at beginning of
1861 the audio. A value of zero indicates no silence should be trimmed from the
1862 beginning. When specifying a non-zero value, it trims audio up until it
1863 finds non-silence. Normally, when trimming silence from beginning of audio
1864 the @var{start_periods} will be @code{1} but it can be increased to higher
1865 values to trim all audio up to specific count of non-silence periods.
1866 Default value is @code{0}.
1868 @item start_duration
1869 Specify the amount of time that non-silence must be detected before it stops
1870 trimming audio. By increasing the duration, bursts of noises can be treated
1871 as silence and trimmed off. Default value is @code{0}.
1873 @item start_threshold
1874 This indicates what sample value should be treated as silence. For digital
1875 audio, a value of @code{0} may be fine but for audio recorded from analog,
1876 you may wish to increase the value to account for background noise.
1877 Can be specified in dB (in case "dB" is appended to the specified value)
1878 or amplitude ratio. Default value is @code{0}.
1881 Set the count for trimming silence from the end of audio.
1882 To remove silence from the middle of a file, specify a @var{stop_periods}
1883 that is negative. This value is then treated as a positive value and is
1884 used to indicate the effect should restart processing as specified by
1885 @var{start_periods}, making it suitable for removing periods of silence
1886 in the middle of the audio.
1887 Default value is @code{0}.
1890 Specify a duration of silence that must exist before audio is not copied any
1891 more. By specifying a higher duration, silence that is wanted can be left in
1893 Default value is @code{0}.
1895 @item stop_threshold
1896 This is the same as @option{start_threshold} but for trimming silence from
1898 Can be specified in dB (in case "dB" is appended to the specified value)
1899 or amplitude ratio. Default value is @code{0}.
1902 This indicate that @var{stop_duration} length of audio should be left intact
1903 at the beginning of each period of silence.
1904 For example, if you want to remove long pauses between words but do not want
1905 to remove the pauses completely. Default value is @code{0}.
1909 @subsection Examples
1913 The following example shows how this filter can be used to start a recording
1914 that does not contain the delay at the start which usually occurs between
1915 pressing the record button and the start of the performance:
1917 silenceremove=1:5:0.02
1923 Boost or cut treble (upper) frequencies of the audio using a two-pole
1924 shelving filter with a response similar to that of a standard
1925 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1927 The filter accepts the following options:
1931 Give the gain at whichever is the lower of ~22 kHz and the
1932 Nyquist frequency. Its useful range is about -20 (for a large cut)
1933 to +20 (for a large boost). Beware of clipping when using a positive gain.
1936 Set the filter's central frequency and so can be used
1937 to extend or reduce the frequency range to be boosted or cut.
1938 The default value is @code{3000} Hz.
1941 Set method to specify band-width of filter.
1954 Determine how steep is the filter's shelf transition.
1959 Adjust the input audio volume.
1961 It accepts the following parameters:
1965 Set audio volume expression.
1967 Output values are clipped to the maximum value.
1969 The output audio volume is given by the relation:
1971 @var{output_volume} = @var{volume} * @var{input_volume}
1974 The default value for @var{volume} is "1.0".
1977 This parameter represents the mathematical precision.
1979 It determines which input sample formats will be allowed, which affects the
1980 precision of the volume scaling.
1984 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
1986 32-bit floating-point; this limits input sample format to FLT. (default)
1988 64-bit floating-point; this limits input sample format to DBL.
1992 Choose the behaviour on encountering ReplayGain side data in input frames.
1996 Remove ReplayGain side data, ignoring its contents (the default).
1999 Ignore ReplayGain side data, but leave it in the frame.
2002 Prefer the track gain, if present.
2005 Prefer the album gain, if present.
2008 @item replaygain_preamp
2009 Pre-amplification gain in dB to apply to the selected replaygain gain.
2011 Default value for @var{replaygain_preamp} is 0.0.
2014 Set when the volume expression is evaluated.
2016 It accepts the following values:
2019 only evaluate expression once during the filter initialization, or
2020 when the @samp{volume} command is sent
2023 evaluate expression for each incoming frame
2026 Default value is @samp{once}.
2029 The volume expression can contain the following parameters.
2033 frame number (starting at zero)
2036 @item nb_consumed_samples
2037 number of samples consumed by the filter
2039 number of samples in the current frame
2041 original frame position in the file
2047 PTS at start of stream
2049 time at start of stream
2055 last set volume value
2058 Note that when @option{eval} is set to @samp{once} only the
2059 @var{sample_rate} and @var{tb} variables are available, all other
2060 variables will evaluate to NAN.
2062 @subsection Commands
2064 This filter supports the following commands:
2067 Modify the volume expression.
2068 The command accepts the same syntax of the corresponding option.
2070 If the specified expression is not valid, it is kept at its current
2072 @item replaygain_noclip
2073 Prevent clipping by limiting the gain applied.
2075 Default value for @var{replaygain_noclip} is 1.
2079 @subsection Examples
2083 Halve the input audio volume:
2087 volume=volume=-6.0206dB
2090 In all the above example the named key for @option{volume} can be
2091 omitted, for example like in:
2097 Increase input audio power by 6 decibels using fixed-point precision:
2099 volume=volume=6dB:precision=fixed
2103 Fade volume after time 10 with an annihilation period of 5 seconds:
2105 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
2109 @section volumedetect
2111 Detect the volume of the input video.
2113 The filter has no parameters. The input is not modified. Statistics about
2114 the volume will be printed in the log when the input stream end is reached.
2116 In particular it will show the mean volume (root mean square), maximum
2117 volume (on a per-sample basis), and the beginning of a histogram of the
2118 registered volume values (from the maximum value to a cumulated 1/1000 of
2121 All volumes are in decibels relative to the maximum PCM value.
2123 @subsection Examples
2125 Here is an excerpt of the output:
2127 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2128 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2129 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2130 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2131 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2132 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2133 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2134 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2135 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2141 The mean square energy is approximately -27 dB, or 10^-2.7.
2143 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2145 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2148 In other words, raising the volume by +4 dB does not cause any clipping,
2149 raising it by +5 dB causes clipping for 6 samples, etc.
2151 @c man end AUDIO FILTERS
2153 @chapter Audio Sources
2154 @c man begin AUDIO SOURCES
2156 Below is a description of the currently available audio sources.
2160 Buffer audio frames, and make them available to the filter chain.
2162 This source is mainly intended for a programmatic use, in particular
2163 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2165 It accepts the following parameters:
2169 The timebase which will be used for timestamps of submitted frames. It must be
2170 either a floating-point number or in @var{numerator}/@var{denominator} form.
2173 The sample rate of the incoming audio buffers.
2176 The sample format of the incoming audio buffers.
2177 Either a sample format name or its corresponding integer representation from
2178 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2180 @item channel_layout
2181 The channel layout of the incoming audio buffers.
2182 Either a channel layout name from channel_layout_map in
2183 @file{libavutil/channel_layout.c} or its corresponding integer representation
2184 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2187 The number of channels of the incoming audio buffers.
2188 If both @var{channels} and @var{channel_layout} are specified, then they
2193 @subsection Examples
2196 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2199 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2200 Since the sample format with name "s16p" corresponds to the number
2201 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2204 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2209 Generate an audio signal specified by an expression.
2211 This source accepts in input one or more expressions (one for each
2212 channel), which are evaluated and used to generate a corresponding
2215 This source accepts the following options:
2219 Set the '|'-separated expressions list for each separate channel. In case the
2220 @option{channel_layout} option is not specified, the selected channel layout
2221 depends on the number of provided expressions. Otherwise the last
2222 specified expression is applied to the remaining output channels.
2224 @item channel_layout, c
2225 Set the channel layout. The number of channels in the specified layout
2226 must be equal to the number of specified expressions.
2229 Set the minimum duration of the sourced audio. See
2230 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2231 for the accepted syntax.
2232 Note that the resulting duration may be greater than the specified
2233 duration, as the generated audio is always cut at the end of a
2236 If not specified, or the expressed duration is negative, the audio is
2237 supposed to be generated forever.
2240 Set the number of samples per channel per each output frame,
2243 @item sample_rate, s
2244 Specify the sample rate, default to 44100.
2247 Each expression in @var{exprs} can contain the following constants:
2251 number of the evaluated sample, starting from 0
2254 time of the evaluated sample expressed in seconds, starting from 0
2261 @subsection Examples
2271 Generate a sin signal with frequency of 440 Hz, set sample rate to
2274 aevalsrc="sin(440*2*PI*t):s=8000"
2278 Generate a two channels signal, specify the channel layout (Front
2279 Center + Back Center) explicitly:
2281 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2285 Generate white noise:
2287 aevalsrc="-2+random(0)"
2291 Generate an amplitude modulated signal:
2293 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2297 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2299 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2306 The null audio source, return unprocessed audio frames. It is mainly useful
2307 as a template and to be employed in analysis / debugging tools, or as
2308 the source for filters which ignore the input data (for example the sox
2311 This source accepts the following options:
2315 @item channel_layout, cl
2317 Specifies the channel layout, and can be either an integer or a string
2318 representing a channel layout. The default value of @var{channel_layout}
2321 Check the channel_layout_map definition in
2322 @file{libavutil/channel_layout.c} for the mapping between strings and
2323 channel layout values.
2325 @item sample_rate, r
2326 Specifies the sample rate, and defaults to 44100.
2329 Set the number of samples per requested frames.
2333 @subsection Examples
2337 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2339 anullsrc=r=48000:cl=4
2343 Do the same operation with a more obvious syntax:
2345 anullsrc=r=48000:cl=mono
2349 All the parameters need to be explicitly defined.
2353 Synthesize a voice utterance using the libflite library.
2355 To enable compilation of this filter you need to configure FFmpeg with
2356 @code{--enable-libflite}.
2358 Note that the flite library is not thread-safe.
2360 The filter accepts the following options:
2365 If set to 1, list the names of the available voices and exit
2366 immediately. Default value is 0.
2369 Set the maximum number of samples per frame. Default value is 512.
2372 Set the filename containing the text to speak.
2375 Set the text to speak.
2378 Set the voice to use for the speech synthesis. Default value is
2379 @code{kal}. See also the @var{list_voices} option.
2382 @subsection Examples
2386 Read from file @file{speech.txt}, and synthesize the text using the
2387 standard flite voice:
2389 flite=textfile=speech.txt
2393 Read the specified text selecting the @code{slt} voice:
2395 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2399 Input text to ffmpeg:
2401 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2405 Make @file{ffplay} speak the specified text, using @code{flite} and
2406 the @code{lavfi} device:
2408 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2412 For more information about libflite, check:
2413 @url{http://www.speech.cs.cmu.edu/flite/}
2417 Generate an audio signal made of a sine wave with amplitude 1/8.
2419 The audio signal is bit-exact.
2421 The filter accepts the following options:
2426 Set the carrier frequency. Default is 440 Hz.
2428 @item beep_factor, b
2429 Enable a periodic beep every second with frequency @var{beep_factor} times
2430 the carrier frequency. Default is 0, meaning the beep is disabled.
2432 @item sample_rate, r
2433 Specify the sample rate, default is 44100.
2436 Specify the duration of the generated audio stream.
2438 @item samples_per_frame
2439 Set the number of samples per output frame, default is 1024.
2442 @subsection Examples
2447 Generate a simple 440 Hz sine wave:
2453 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2457 sine=frequency=220:beep_factor=4:duration=5
2462 @c man end AUDIO SOURCES
2464 @chapter Audio Sinks
2465 @c man begin AUDIO SINKS
2467 Below is a description of the currently available audio sinks.
2469 @section abuffersink
2471 Buffer audio frames, and make them available to the end of filter chain.
2473 This sink is mainly intended for programmatic use, in particular
2474 through the interface defined in @file{libavfilter/buffersink.h}
2475 or the options system.
2477 It accepts a pointer to an AVABufferSinkContext structure, which
2478 defines the incoming buffers' formats, to be passed as the opaque
2479 parameter to @code{avfilter_init_filter} for initialization.
2482 Null audio sink; do absolutely nothing with the input audio. It is
2483 mainly useful as a template and for use in analysis / debugging
2486 @c man end AUDIO SINKS
2488 @chapter Video Filters
2489 @c man begin VIDEO FILTERS
2491 When you configure your FFmpeg build, you can disable any of the
2492 existing filters using @code{--disable-filters}.
2493 The configure output will show the video filters included in your
2496 Below is a description of the currently available video filters.
2498 @section alphaextract
2500 Extract the alpha component from the input as a grayscale video. This
2501 is especially useful with the @var{alphamerge} filter.
2505 Add or replace the alpha component of the primary input with the
2506 grayscale value of a second input. This is intended for use with
2507 @var{alphaextract} to allow the transmission or storage of frame
2508 sequences that have alpha in a format that doesn't support an alpha
2511 For example, to reconstruct full frames from a normal YUV-encoded video
2512 and a separate video created with @var{alphaextract}, you might use:
2514 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2517 Since this filter is designed for reconstruction, it operates on frame
2518 sequences without considering timestamps, and terminates when either
2519 input reaches end of stream. This will cause problems if your encoding
2520 pipeline drops frames. If you're trying to apply an image as an
2521 overlay to a video stream, consider the @var{overlay} filter instead.
2525 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2526 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2527 Substation Alpha) subtitles files.
2529 This filter accepts the following option in addition to the common options from
2530 the @ref{subtitles} filter:
2534 Set the shaping engine
2536 Available values are:
2539 The default libass shaping engine, which is the best available.
2541 Fast, font-agnostic shaper that can do only substitutions
2543 Slower shaper using OpenType for substitutions and positioning
2546 The default is @code{auto}.
2551 Compute the bounding box for the non-black pixels in the input frame
2554 This filter computes the bounding box containing all the pixels with a
2555 luminance value greater than the minimum allowed value.
2556 The parameters describing the bounding box are printed on the filter
2559 The filter accepts the following option:
2563 Set the minimal luminance value. Default is @code{16}.
2566 @section blackdetect
2568 Detect video intervals that are (almost) completely black. Can be
2569 useful to detect chapter transitions, commercials, or invalid
2570 recordings. Output lines contains the time for the start, end and
2571 duration of the detected black interval expressed in seconds.
2573 In order to display the output lines, you need to set the loglevel at
2574 least to the AV_LOG_INFO value.
2576 The filter accepts the following options:
2579 @item black_min_duration, d
2580 Set the minimum detected black duration expressed in seconds. It must
2581 be a non-negative floating point number.
2583 Default value is 2.0.
2585 @item picture_black_ratio_th, pic_th
2586 Set the threshold for considering a picture "black".
2587 Express the minimum value for the ratio:
2589 @var{nb_black_pixels} / @var{nb_pixels}
2592 for which a picture is considered black.
2593 Default value is 0.98.
2595 @item pixel_black_th, pix_th
2596 Set the threshold for considering a pixel "black".
2598 The threshold expresses the maximum pixel luminance value for which a
2599 pixel is considered "black". The provided value is scaled according to
2600 the following equation:
2602 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2605 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2606 the input video format, the range is [0-255] for YUV full-range
2607 formats and [16-235] for YUV non full-range formats.
2609 Default value is 0.10.
2612 The following example sets the maximum pixel threshold to the minimum
2613 value, and detects only black intervals of 2 or more seconds:
2615 blackdetect=d=2:pix_th=0.00
2620 Detect frames that are (almost) completely black. Can be useful to
2621 detect chapter transitions or commercials. Output lines consist of
2622 the frame number of the detected frame, the percentage of blackness,
2623 the position in the file if known or -1 and the timestamp in seconds.
2625 In order to display the output lines, you need to set the loglevel at
2626 least to the AV_LOG_INFO value.
2628 It accepts the following parameters:
2633 The percentage of the pixels that have to be below the threshold; it defaults to
2636 @item threshold, thresh
2637 The threshold below which a pixel value is considered black; it defaults to
2642 @section blend, tblend
2644 Blend two video frames into each other.
2646 The @code{blend} filter takes two input streams and outputs one
2647 stream, the first input is the "top" layer and second input is
2648 "bottom" layer. Output terminates when shortest input terminates.
2650 The @code{tblend} (time blend) filter takes two consecutive frames
2651 from one single stream, and outputs the result obtained by blending
2652 the new frame on top of the old frame.
2654 A description of the accepted options follows.
2662 Set blend mode for specific pixel component or all pixel components in case
2663 of @var{all_mode}. Default value is @code{normal}.
2665 Available values for component modes are:
2699 Set blend opacity for specific pixel component or all pixel components in case
2700 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2707 Set blend expression for specific pixel component or all pixel components in case
2708 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2710 The expressions can use the following variables:
2714 The sequential number of the filtered frame, starting from @code{0}.
2718 the coordinates of the current sample
2722 the width and height of currently filtered plane
2726 Width and height scale depending on the currently filtered plane. It is the
2727 ratio between the corresponding luma plane number of pixels and the current
2728 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2729 @code{0.5,0.5} for chroma planes.
2732 Time of the current frame, expressed in seconds.
2735 Value of pixel component at current location for first video frame (top layer).
2738 Value of pixel component at current location for second video frame (bottom layer).
2742 Force termination when the shortest input terminates. Default is
2743 @code{0}. This option is only defined for the @code{blend} filter.
2746 Continue applying the last bottom frame after the end of the stream. A value of
2747 @code{0} disable the filter after the last frame of the bottom layer is reached.
2748 Default is @code{1}. This option is only defined for the @code{blend} filter.
2751 @subsection Examples
2755 Apply transition from bottom layer to top layer in first 10 seconds:
2757 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2761 Apply 1x1 checkerboard effect:
2763 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2767 Apply uncover left effect:
2769 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2773 Apply uncover down effect:
2775 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2779 Apply uncover up-left effect:
2781 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2785 Display differences between the current and the previous frame:
2787 tblend=all_mode=difference128
2793 Apply a boxblur algorithm to the input video.
2795 It accepts the following parameters:
2799 @item luma_radius, lr
2800 @item luma_power, lp
2801 @item chroma_radius, cr
2802 @item chroma_power, cp
2803 @item alpha_radius, ar
2804 @item alpha_power, ap
2808 A description of the accepted options follows.
2811 @item luma_radius, lr
2812 @item chroma_radius, cr
2813 @item alpha_radius, ar
2814 Set an expression for the box radius in pixels used for blurring the
2815 corresponding input plane.
2817 The radius value must be a non-negative number, and must not be
2818 greater than the value of the expression @code{min(w,h)/2} for the
2819 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2822 Default value for @option{luma_radius} is "2". If not specified,
2823 @option{chroma_radius} and @option{alpha_radius} default to the
2824 corresponding value set for @option{luma_radius}.
2826 The expressions can contain the following constants:
2830 The input width and height in pixels.
2834 The input chroma image width and height in pixels.
2838 The horizontal and vertical chroma subsample values. For example, for the
2839 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
2842 @item luma_power, lp
2843 @item chroma_power, cp
2844 @item alpha_power, ap
2845 Specify how many times the boxblur filter is applied to the
2846 corresponding plane.
2848 Default value for @option{luma_power} is 2. If not specified,
2849 @option{chroma_power} and @option{alpha_power} default to the
2850 corresponding value set for @option{luma_power}.
2852 A value of 0 will disable the effect.
2855 @subsection Examples
2859 Apply a boxblur filter with the luma, chroma, and alpha radii
2862 boxblur=luma_radius=2:luma_power=1
2867 Set the luma radius to 2, and alpha and chroma radius to 0:
2869 boxblur=2:1:cr=0:ar=0
2873 Set the luma and chroma radii to a fraction of the video dimension:
2875 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2881 Visualize information exported by some codecs.
2883 Some codecs can export information through frames using side-data or other
2884 means. For example, some MPEG based codecs export motion vectors through the
2885 @var{export_mvs} flag in the codec @option{flags2} option.
2887 The filter accepts the following option:
2891 Set motion vectors to visualize.
2893 Available flags for @var{mv} are:
2897 forward predicted MVs of P-frames
2899 forward predicted MVs of B-frames
2901 backward predicted MVs of B-frames
2905 @subsection Examples
2909 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
2911 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
2915 @section colorbalance
2916 Modify intensity of primary colors (red, green and blue) of input frames.
2918 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2919 regions for the red-cyan, green-magenta or blue-yellow balance.
2921 A positive adjustment value shifts the balance towards the primary color, a negative
2922 value towards the complementary color.
2924 The filter accepts the following options:
2930 Adjust red, green and blue shadows (darkest pixels).
2935 Adjust red, green and blue midtones (medium pixels).
2940 Adjust red, green and blue highlights (brightest pixels).
2942 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2945 @subsection Examples
2949 Add red color cast to shadows:
2955 @section colorlevels
2957 Adjust video input frames using levels.
2959 The filter accepts the following options:
2966 Adjust red, green, blue and alpha input black point.
2967 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2973 Adjust red, green, blue and alpha input white point.
2974 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
2976 Input levels are used to lighten highlights (bright tones), darken shadows
2977 (dark tones), change the balance of bright and dark tones.
2983 Adjust red, green, blue and alpha output black point.
2984 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
2990 Adjust red, green, blue and alpha output white point.
2991 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
2993 Output levels allows manual selection of a constrained output level range.
2996 @subsection Examples
3000 Make video output darker:
3002 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
3008 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
3012 Make video output lighter:
3014 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
3018 Increase brightness:
3020 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
3024 @section colorchannelmixer
3026 Adjust video input frames by re-mixing color channels.
3028 This filter modifies a color channel by adding the values associated to
3029 the other channels of the same pixels. For example if the value to
3030 modify is red, the output value will be:
3032 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
3035 The filter accepts the following options:
3042 Adjust contribution of input red, green, blue and alpha channels for output red channel.
3043 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
3049 Adjust contribution of input red, green, blue and alpha channels for output green channel.
3050 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
3056 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
3057 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
3063 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
3064 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
3066 Allowed ranges for options are @code{[-2.0, 2.0]}.
3069 @subsection Examples
3073 Convert source to grayscale:
3075 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
3078 Simulate sepia tones:
3080 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
3084 @section colormatrix
3086 Convert color matrix.
3088 The filter accepts the following options:
3093 Specify the source and destination color matrix. Both values must be
3096 The accepted values are:
3112 For example to convert from BT.601 to SMPTE-240M, use the command:
3114 colormatrix=bt601:smpte240m
3119 Copy the input source unchanged to the output. This is mainly useful for
3124 Crop the input video to given dimensions.
3126 It accepts the following parameters:
3130 The width of the output video. It defaults to @code{iw}.
3131 This expression is evaluated only once during the filter
3135 The height of the output video. It defaults to @code{ih}.
3136 This expression is evaluated only once during the filter
3140 The horizontal position, in the input video, of the left edge of the output
3141 video. It defaults to @code{(in_w-out_w)/2}.
3142 This expression is evaluated per-frame.
3145 The vertical position, in the input video, of the top edge of the output video.
3146 It defaults to @code{(in_h-out_h)/2}.
3147 This expression is evaluated per-frame.
3150 If set to 1 will force the output display aspect ratio
3151 to be the same of the input, by changing the output sample aspect
3152 ratio. It defaults to 0.
3155 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
3156 expressions containing the following constants:
3161 The computed values for @var{x} and @var{y}. They are evaluated for
3166 The input width and height.
3170 These are the same as @var{in_w} and @var{in_h}.
3174 The output (cropped) width and height.
3178 These are the same as @var{out_w} and @var{out_h}.
3181 same as @var{iw} / @var{ih}
3184 input sample aspect ratio
3187 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
3191 horizontal and vertical chroma subsample values. For example for the
3192 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3195 The number of the input frame, starting from 0.
3198 the position in the file of the input frame, NAN if unknown
3201 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
3205 The expression for @var{out_w} may depend on the value of @var{out_h},
3206 and the expression for @var{out_h} may depend on @var{out_w}, but they
3207 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
3208 evaluated after @var{out_w} and @var{out_h}.
3210 The @var{x} and @var{y} parameters specify the expressions for the
3211 position of the top-left corner of the output (non-cropped) area. They
3212 are evaluated for each frame. If the evaluated value is not valid, it
3213 is approximated to the nearest valid value.
3215 The expression for @var{x} may depend on @var{y}, and the expression
3216 for @var{y} may depend on @var{x}.
3218 @subsection Examples
3222 Crop area with size 100x100 at position (12,34).
3227 Using named options, the example above becomes:
3229 crop=w=100:h=100:x=12:y=34
3233 Crop the central input area with size 100x100:
3239 Crop the central input area with size 2/3 of the input video:
3241 crop=2/3*in_w:2/3*in_h
3245 Crop the input video central square:
3252 Delimit the rectangle with the top-left corner placed at position
3253 100:100 and the right-bottom corner corresponding to the right-bottom
3254 corner of the input image.
3256 crop=in_w-100:in_h-100:100:100
3260 Crop 10 pixels from the left and right borders, and 20 pixels from
3261 the top and bottom borders
3263 crop=in_w-2*10:in_h-2*20
3267 Keep only the bottom right quarter of the input image:
3269 crop=in_w/2:in_h/2:in_w/2:in_h/2
3273 Crop height for getting Greek harmony:
3275 crop=in_w:1/PHI*in_w
3279 Apply trembling effect:
3281 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)
3285 Apply erratic camera effect depending on timestamp:
3287 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)"
3291 Set x depending on the value of y:
3293 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3299 Auto-detect the crop size.
3301 It calculates the necessary cropping parameters and prints the
3302 recommended parameters via the logging system. The detected dimensions
3303 correspond to the non-black area of the input video.
3305 It accepts the following parameters:
3310 Set higher black value threshold, which can be optionally specified
3311 from nothing (0) to everything (255 for 8bit based formats). An intensity
3312 value greater to the set value is considered non-black. It defaults to 24.
3313 You can also specify a value between 0.0 and 1.0 which will be scaled depending
3314 on the bitdepth of the pixel format.
3317 The value which the width/height should be divisible by. It defaults to
3318 16. The offset is automatically adjusted to center the video. Use 2 to
3319 get only even dimensions (needed for 4:2:2 video). 16 is best when
3320 encoding to most video codecs.
3322 @item reset_count, reset
3323 Set the counter that determines after how many frames cropdetect will
3324 reset the previously detected largest video area and start over to
3325 detect the current optimal crop area. Default value is 0.
3327 This can be useful when channel logos distort the video area. 0
3328 indicates 'never reset', and returns the largest area encountered during
3335 Apply color adjustments using curves.
3337 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3338 component (red, green and blue) has its values defined by @var{N} key points
3339 tied from each other using a smooth curve. The x-axis represents the pixel
3340 values from the input frame, and the y-axis the new pixel values to be set for
3343 By default, a component curve is defined by the two points @var{(0;0)} and
3344 @var{(1;1)}. This creates a straight line where each original pixel value is
3345 "adjusted" to its own value, which means no change to the image.
3347 The filter allows you to redefine these two points and add some more. A new
3348 curve (using a natural cubic spline interpolation) will be define to pass
3349 smoothly through all these new coordinates. The new defined points needs to be
3350 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3351 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3352 the vector spaces, the values will be clipped accordingly.
3354 If there is no key point defined in @code{x=0}, the filter will automatically
3355 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3356 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3358 The filter accepts the following options:
3362 Select one of the available color presets. This option can be used in addition
3363 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3364 options takes priority on the preset values.
3365 Available presets are:
3368 @item color_negative
3371 @item increase_contrast
3373 @item linear_contrast
3374 @item medium_contrast
3376 @item strong_contrast
3379 Default is @code{none}.
3381 Set the master key points. These points will define a second pass mapping. It
3382 is sometimes called a "luminance" or "value" mapping. It can be used with
3383 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3384 post-processing LUT.
3386 Set the key points for the red component.
3388 Set the key points for the green component.
3390 Set the key points for the blue component.
3392 Set the key points for all components (not including master).
3393 Can be used in addition to the other key points component
3394 options. In this case, the unset component(s) will fallback on this
3395 @option{all} setting.
3397 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3400 To avoid some filtergraph syntax conflicts, each key points list need to be
3401 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3403 @subsection Examples
3407 Increase slightly the middle level of blue:
3409 curves=blue='0.5/0.58'
3415 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3417 Here we obtain the following coordinates for each components:
3420 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3422 @code{(0;0) (0.50;0.48) (1;1)}
3424 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3428 The previous example can also be achieved with the associated built-in preset:
3430 curves=preset=vintage
3440 Use a Photoshop preset and redefine the points of the green component:
3442 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3448 Denoise frames using 2D DCT (frequency domain filtering).
3450 This filter is not designed for real time.
3452 The filter accepts the following options:
3456 Set the noise sigma constant.
3458 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3459 coefficient (absolute value) below this threshold with be dropped.
3461 If you need a more advanced filtering, see @option{expr}.
3463 Default is @code{0}.
3466 Set number overlapping pixels for each block. Since the filter can be slow, you
3467 may want to reduce this value, at the cost of a less effective filter and the
3468 risk of various artefacts.
3470 If the overlapping value doesn't allow to process the whole input width or
3471 height, a warning will be displayed and according borders won't be denoised.
3473 Default value is @var{blocksize}-1, which is the best possible setting.
3476 Set the coefficient factor expression.
3478 For each coefficient of a DCT block, this expression will be evaluated as a
3479 multiplier value for the coefficient.
3481 If this is option is set, the @option{sigma} option will be ignored.
3483 The absolute value of the coefficient can be accessed through the @var{c}
3487 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
3488 @var{blocksize}, which is the width and height of the processed blocks.
3490 The default value is @var{3} (8x8) and can be raised to @var{4} for a
3491 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
3492 on the speed processing. Also, a larger block size does not necessarily means a
3496 @subsection Examples
3498 Apply a denoise with a @option{sigma} of @code{4.5}:
3503 The same operation can be achieved using the expression system:
3505 dctdnoiz=e='gte(c, 4.5*3)'
3508 Violent denoise using a block size of @code{16x16}:
3516 Drop duplicated frames at regular intervals.
3518 The filter accepts the following options:
3522 Set the number of frames from which one will be dropped. Setting this to
3523 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3524 Default is @code{5}.
3527 Set the threshold for duplicate detection. If the difference metric for a frame
3528 is less than or equal to this value, then it is declared as duplicate. Default
3532 Set scene change threshold. Default is @code{15}.
3536 Set the size of the x and y-axis blocks used during metric calculations.
3537 Larger blocks give better noise suppression, but also give worse detection of
3538 small movements. Must be a power of two. Default is @code{32}.
3541 Mark main input as a pre-processed input and activate clean source input
3542 stream. This allows the input to be pre-processed with various filters to help
3543 the metrics calculation while keeping the frame selection lossless. When set to
3544 @code{1}, the first stream is for the pre-processed input, and the second
3545 stream is the clean source from where the kept frames are chosen. Default is
3549 Set whether or not chroma is considered in the metric calculations. Default is
3555 Remove judder produced by partially interlaced telecined content.
3557 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3558 source was partially telecined content then the output of @code{pullup,dejudder}
3559 will have a variable frame rate. May change the recorded frame rate of the
3560 container. Aside from that change, this filter will not affect constant frame
3563 The option available in this filter is:
3567 Specify the length of the window over which the judder repeats.
3569 Accepts any integer greater than 1. Useful values are:
3573 If the original was telecined from 24 to 30 fps (Film to NTSC).
3576 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3579 If a mixture of the two.
3582 The default is @samp{4}.
3587 Suppress a TV station logo by a simple interpolation of the surrounding
3588 pixels. Just set a rectangle covering the logo and watch it disappear
3589 (and sometimes something even uglier appear - your mileage may vary).
3591 It accepts the following parameters:
3596 Specify the top left corner coordinates of the logo. They must be
3601 Specify the width and height of the logo to clear. They must be
3605 Specify the thickness of the fuzzy edge of the rectangle (added to
3606 @var{w} and @var{h}). The default value is 4.
3609 When set to 1, a green rectangle is drawn on the screen to simplify
3610 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3611 The default value is 0.
3613 The rectangle is drawn on the outermost pixels which will be (partly)
3614 replaced with interpolated values. The values of the next pixels
3615 immediately outside this rectangle in each direction will be used to
3616 compute the interpolated pixel values inside the rectangle.
3620 @subsection Examples
3624 Set a rectangle covering the area with top left corner coordinates 0,0
3625 and size 100x77, and a band of size 10:
3627 delogo=x=0:y=0:w=100:h=77:band=10
3634 Attempt to fix small changes in horizontal and/or vertical shift. This
3635 filter helps remove camera shake from hand-holding a camera, bumping a
3636 tripod, moving on a vehicle, etc.
3638 The filter accepts the following options:
3646 Specify a rectangular area where to limit the search for motion
3648 If desired the search for motion vectors can be limited to a
3649 rectangular area of the frame defined by its top left corner, width
3650 and height. These parameters have the same meaning as the drawbox
3651 filter which can be used to visualise the position of the bounding
3654 This is useful when simultaneous movement of subjects within the frame
3655 might be confused for camera motion by the motion vector search.
3657 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3658 then the full frame is used. This allows later options to be set
3659 without specifying the bounding box for the motion vector search.
3661 Default - search the whole frame.
3665 Specify the maximum extent of movement in x and y directions in the
3666 range 0-64 pixels. Default 16.
3669 Specify how to generate pixels to fill blanks at the edge of the
3670 frame. Available values are:
3673 Fill zeroes at blank locations
3675 Original image at blank locations
3677 Extruded edge value at blank locations
3679 Mirrored edge at blank locations
3681 Default value is @samp{mirror}.
3684 Specify the blocksize to use for motion search. Range 4-128 pixels,
3688 Specify the contrast threshold for blocks. Only blocks with more than
3689 the specified contrast (difference between darkest and lightest
3690 pixels) will be considered. Range 1-255, default 125.
3693 Specify the search strategy. Available values are:
3696 Set exhaustive search
3698 Set less exhaustive search.
3700 Default value is @samp{exhaustive}.
3703 If set then a detailed log of the motion search is written to the
3707 If set to 1, specify using OpenCL capabilities, only available if
3708 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3714 Draw a colored box on the input image.
3716 It accepts the following parameters:
3721 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3725 The expressions which specify the width and height of the box; if 0 they are interpreted as
3726 the input width and height. It defaults to 0.
3729 Specify the color of the box to write. For the general syntax of this option,
3730 check the "Color" section in the ffmpeg-utils manual. If the special
3731 value @code{invert} is used, the box edge color is the same as the
3732 video with inverted luma.
3735 The expression which sets the thickness of the box edge. Default value is @code{3}.
3737 See below for the list of accepted constants.
3740 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3741 following constants:
3745 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3749 horizontal and vertical chroma subsample values. For example for the
3750 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3754 The input width and height.
3757 The input sample aspect ratio.
3761 The x and y offset coordinates where the box is drawn.
3765 The width and height of the drawn box.
3768 The thickness of the drawn box.
3770 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3771 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3775 @subsection Examples
3779 Draw a black box around the edge of the input image:
3785 Draw a box with color red and an opacity of 50%:
3787 drawbox=10:20:200:60:red@@0.5
3790 The previous example can be specified as:
3792 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3796 Fill the box with pink color:
3798 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3802 Draw a 2-pixel red 2.40:1 mask:
3804 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
3810 Draw a grid on the input image.
3812 It accepts the following parameters:
3817 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3821 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3822 input width and height, respectively, minus @code{thickness}, so image gets
3823 framed. Default to 0.
3826 Specify the color of the grid. For the general syntax of this option,
3827 check the "Color" section in the ffmpeg-utils manual. If the special
3828 value @code{invert} is used, the grid color is the same as the
3829 video with inverted luma.
3832 The expression which sets the thickness of the grid line. Default value is @code{1}.
3834 See below for the list of accepted constants.
3837 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3838 following constants:
3842 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3846 horizontal and vertical chroma subsample values. For example for the
3847 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3851 The input grid cell width and height.
3854 The input sample aspect ratio.
3858 The x and y coordinates of some point of grid intersection (meant to configure offset).
3862 The width and height of the drawn cell.
3865 The thickness of the drawn cell.
3867 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3868 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3872 @subsection Examples
3876 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3878 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3882 Draw a white 3x3 grid with an opacity of 50%:
3884 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3891 Draw a text string or text from a specified file on top of a video, using the
3892 libfreetype library.
3894 To enable compilation of this filter, you need to configure FFmpeg with
3895 @code{--enable-libfreetype}.
3896 To enable default font fallback and the @var{font} option you need to
3897 configure FFmpeg with @code{--enable-libfontconfig}.
3898 To enable the @var{text_shaping} option, you need to configure FFmpeg with
3899 @code{--enable-libfribidi}.
3903 It accepts the following parameters:
3908 Used to draw a box around text using the background color.
3909 The value must be either 1 (enable) or 0 (disable).
3910 The default value of @var{box} is 0.
3913 The color to be used for drawing box around text. For the syntax of this
3914 option, check the "Color" section in the ffmpeg-utils manual.
3916 The default value of @var{boxcolor} is "white".
3919 Set the width of the border to be drawn around the text using @var{bordercolor}.
3920 The default value of @var{borderw} is 0.
3923 Set the color to be used for drawing border around text. For the syntax of this
3924 option, check the "Color" section in the ffmpeg-utils manual.
3926 The default value of @var{bordercolor} is "black".
3929 Select how the @var{text} is expanded. Can be either @code{none},
3930 @code{strftime} (deprecated) or
3931 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3935 If true, check and fix text coords to avoid clipping.
3938 The color to be used for drawing fonts. For the syntax of this option, check
3939 the "Color" section in the ffmpeg-utils manual.
3941 The default value of @var{fontcolor} is "black".
3943 @item fontcolor_expr
3944 String which is expanded the same way as @var{text} to obtain dynamic
3945 @var{fontcolor} value. By default this option has empty value and is not
3946 processed. When this option is set, it overrides @var{fontcolor} option.
3949 The font family to be used for drawing text. By default Sans.
3952 The font file to be used for drawing text. The path must be included.
3953 This parameter is mandatory if the fontconfig support is disabled.
3956 The font size to be used for drawing text.
3957 The default value of @var{fontsize} is 16.
3960 If set to 1, attempt to shape the text (for example, reverse the order of
3961 right-to-left text and join Arabic characters) before drawing it.
3962 Otherwise, just draw the text exactly as given.
3963 By default 1 (if supported).
3966 The flags to be used for loading the fonts.
3968 The flags map the corresponding flags supported by libfreetype, and are
3969 a combination of the following values:
3976 @item vertical_layout
3977 @item force_autohint
3980 @item ignore_global_advance_width
3982 @item ignore_transform
3988 Default value is "default".
3990 For more information consult the documentation for the FT_LOAD_*
3994 The color to be used for drawing a shadow behind the drawn text. For the
3995 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3997 The default value of @var{shadowcolor} is "black".
4001 The x and y offsets for the text shadow position with respect to the
4002 position of the text. They can be either positive or negative
4003 values. The default value for both is "0".
4006 The starting frame number for the n/frame_num variable. The default value
4010 The size in number of spaces to use for rendering the tab.
4014 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
4015 format. It can be used with or without text parameter. @var{timecode_rate}
4016 option must be specified.
4018 @item timecode_rate, rate, r
4019 Set the timecode frame rate (timecode only).
4022 The text string to be drawn. The text must be a sequence of UTF-8
4024 This parameter is mandatory if no file is specified with the parameter
4028 A text file containing text to be drawn. The text must be a sequence
4029 of UTF-8 encoded characters.
4031 This parameter is mandatory if no text string is specified with the
4032 parameter @var{text}.
4034 If both @var{text} and @var{textfile} are specified, an error is thrown.
4037 If set to 1, the @var{textfile} will be reloaded before each frame.
4038 Be sure to update it atomically, or it may be read partially, or even fail.
4042 The expressions which specify the offsets where text will be drawn
4043 within the video frame. They are relative to the top/left border of the
4046 The default value of @var{x} and @var{y} is "0".
4048 See below for the list of accepted constants and functions.
4051 The parameters for @var{x} and @var{y} are expressions containing the
4052 following constants and functions:
4056 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
4060 horizontal and vertical chroma subsample values. For example for the
4061 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4064 the height of each text line
4072 @item max_glyph_a, ascent
4073 the maximum distance from the baseline to the highest/upper grid
4074 coordinate used to place a glyph outline point, for all the rendered
4076 It is a positive value, due to the grid's orientation with the Y axis
4079 @item max_glyph_d, descent
4080 the maximum distance from the baseline to the lowest grid coordinate
4081 used to place a glyph outline point, for all the rendered glyphs.
4082 This is a negative value, due to the grid's orientation, with the Y axis
4086 maximum glyph height, that is the maximum height for all the glyphs
4087 contained in the rendered text, it is equivalent to @var{ascent} -
4091 maximum glyph width, that is the maximum width for all the glyphs
4092 contained in the rendered text
4095 the number of input frame, starting from 0
4097 @item rand(min, max)
4098 return a random number included between @var{min} and @var{max}
4101 The input sample aspect ratio.
4104 timestamp expressed in seconds, NAN if the input timestamp is unknown
4107 the height of the rendered text
4110 the width of the rendered text
4114 the x and y offset coordinates where the text is drawn.
4116 These parameters allow the @var{x} and @var{y} expressions to refer
4117 each other, so you can for example specify @code{y=x/dar}.
4120 @anchor{drawtext_expansion}
4121 @subsection Text expansion
4123 If @option{expansion} is set to @code{strftime},
4124 the filter recognizes strftime() sequences in the provided text and
4125 expands them accordingly. Check the documentation of strftime(). This
4126 feature is deprecated.
4128 If @option{expansion} is set to @code{none}, the text is printed verbatim.
4130 If @option{expansion} is set to @code{normal} (which is the default),
4131 the following expansion mechanism is used.
4133 The backslash character '\', followed by any character, always expands to
4134 the second character.
4136 Sequence of the form @code{%@{...@}} are expanded. The text between the
4137 braces is a function name, possibly followed by arguments separated by ':'.
4138 If the arguments contain special characters or delimiters (':' or '@}'),
4139 they should be escaped.
4141 Note that they probably must also be escaped as the value for the
4142 @option{text} option in the filter argument string and as the filter
4143 argument in the filtergraph description, and possibly also for the shell,
4144 that makes up to four levels of escaping; using a text file avoids these
4147 The following functions are available:
4152 The expression evaluation result.
4154 It must take one argument specifying the expression to be evaluated,
4155 which accepts the same constants and functions as the @var{x} and
4156 @var{y} values. Note that not all constants should be used, for
4157 example the text size is not known when evaluating the expression, so
4158 the constants @var{text_w} and @var{text_h} will have an undefined
4161 @item expr_int_format, eif
4162 Evaluate the expression's value and output as formatted integer.
4164 The first argument is the expression to be evaluated, just as for the @var{expr} function.
4165 The second argument specifies the output format. Allowed values are 'x', 'X', 'd' and
4166 'u'. They are treated exactly as in the printf function.
4167 The third parameter is optional and sets the number of positions taken by the output.
4168 It can be used to add padding with zeros from the left.
4171 The time at which the filter is running, expressed in UTC.
4172 It can accept an argument: a strftime() format string.
4175 The time at which the filter is running, expressed in the local time zone.
4176 It can accept an argument: a strftime() format string.
4179 Frame metadata. It must take one argument specifying metadata key.
4182 The frame number, starting from 0.
4185 A 1 character description of the current picture type.
4188 The timestamp of the current frame.
4189 It can take up to two arguments.
4191 The first argument is the format of the timestamp; it defaults to @code{flt}
4192 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
4193 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
4195 The second argument is an offset added to the timestamp.
4199 @subsection Examples
4203 Draw "Test Text" with font FreeSerif, using the default values for the
4204 optional parameters.
4207 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
4211 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
4212 and y=50 (counting from the top-left corner of the screen), text is
4213 yellow with a red box around it. Both the text and the box have an
4217 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
4218 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
4221 Note that the double quotes are not necessary if spaces are not used
4222 within the parameter list.
4225 Show the text at the center of the video frame:
4227 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
4231 Show a text line sliding from right to left in the last row of the video
4232 frame. The file @file{LONG_LINE} is assumed to contain a single line
4235 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
4239 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
4241 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
4245 Draw a single green letter "g", at the center of the input video.
4246 The glyph baseline is placed at half screen height.
4248 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
4252 Show text for 1 second every 3 seconds:
4254 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
4258 Use fontconfig to set the font. Note that the colons need to be escaped.
4260 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
4264 Print the date of a real-time encoding (see strftime(3)):
4266 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
4270 Show text fading in and out (appearing/disappearing):
4273 DS=1.0 # display start
4274 DE=10.0 # display end
4275 FID=1.5 # fade in duration
4276 FOD=5 # fade out duration
4277 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 @}"
4282 For more information about libfreetype, check:
4283 @url{http://www.freetype.org/}.
4285 For more information about fontconfig, check:
4286 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
4288 For more information about libfribidi, check:
4289 @url{http://fribidi.org/}.
4293 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
4295 The filter accepts the following options:
4300 Set low and high threshold values used by the Canny thresholding
4303 The high threshold selects the "strong" edge pixels, which are then
4304 connected through 8-connectivity with the "weak" edge pixels selected
4305 by the low threshold.
4307 @var{low} and @var{high} threshold values must be chosen in the range
4308 [0,1], and @var{low} should be lesser or equal to @var{high}.
4310 Default value for @var{low} is @code{20/255}, and default value for @var{high}
4314 Define the drawing mode.
4318 Draw white/gray wires on black background.
4321 Mix the colors to create a paint/cartoon effect.
4324 Default value is @var{wires}.
4327 @subsection Examples
4331 Standard edge detection with custom values for the hysteresis thresholding:
4333 edgedetect=low=0.1:high=0.4
4337 Painting effect without thresholding:
4339 edgedetect=mode=colormix:high=0
4344 Set brightness, contrast, saturation and approximate gamma adjustment.
4346 The filter accepts the following options:
4350 Set the contrast value. It accepts a float value in range @code{-2.0} to
4351 @code{2.0}. The default value is @code{0.0}.
4354 Set the brightness value. It accepts a float value in range @code{-1.0} to
4355 @code{1.0}. The default value is @code{0.0}.
4358 Set the saturation value. It accepts a float value in range @code{0.0} to
4359 @code{3.0}. The default value is @code{1.0}.
4362 Set the gamma value. It accepts a float value in range @code{0.1} to @code{10.0}.
4363 The default value is @code{1.0}.
4366 Set the gamma value for red. It accepts a float value in range
4367 @code{0.1} to @code{10.0}. The default value is @code{1.0}.
4370 Set the gamma value for green. It accepts a float value in range
4371 @code{0.1} to @code{10.0}. The default value is @code{1.0}.
4374 Set the gamma value for blue. It accepts a float value in range
4375 @code{0.1} to @code{10.0}. The default value is @code{1.0}.
4378 Can be used to reduce the effect of a high gamma value on bright image areas,
4379 e.g. keep them from getting overamplified and just plain white. It accepts a
4380 float value in range @code{0.0} to @code{1.0}.A value of @code{0.0} turns the
4381 gamma correction all the way down while @code{1.0} leaves it at its full strength.
4382 Default is @code{1.0}.
4386 @section extractplanes
4388 Extract color channel components from input video stream into
4389 separate grayscale video streams.
4391 The filter accepts the following option:
4395 Set plane(s) to extract.
4397 Available values for planes are:
4408 Choosing planes not available in the input will result in an error.
4409 That means you cannot select @code{r}, @code{g}, @code{b} planes
4410 with @code{y}, @code{u}, @code{v} planes at same time.
4413 @subsection Examples
4417 Extract luma, u and v color channel component from input video frame
4418 into 3 grayscale outputs:
4420 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
4426 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4428 For each input image, the filter will compute the optimal mapping from
4429 the input to the output given the codebook length, that is the number
4430 of distinct output colors.
4432 This filter accepts the following options.
4435 @item codebook_length, l
4436 Set codebook length. The value must be a positive integer, and
4437 represents the number of distinct output colors. Default value is 256.
4440 Set the maximum number of iterations to apply for computing the optimal
4441 mapping. The higher the value the better the result and the higher the
4442 computation time. Default value is 1.
4445 Set a random seed, must be an integer included between 0 and
4446 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4447 will try to use a good random seed on a best effort basis.
4452 Apply a fade-in/out effect to the input video.
4454 It accepts the following parameters:
4458 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4460 Default is @code{in}.
4462 @item start_frame, s
4463 Specify the number of the frame to start applying the fade
4464 effect at. Default is 0.
4467 The number of frames that the fade effect lasts. At the end of the
4468 fade-in effect, the output video will have the same intensity as the input video.
4469 At the end of the fade-out transition, the output video will be filled with the
4470 selected @option{color}.
4474 If set to 1, fade only alpha channel, if one exists on the input.
4477 @item start_time, st
4478 Specify the timestamp (in seconds) of the frame to start to apply the fade
4479 effect. If both start_frame and start_time are specified, the fade will start at
4480 whichever comes last. Default is 0.
4483 The number of seconds for which the fade effect has to last. At the end of the
4484 fade-in effect the output video will have the same intensity as the input video,
4485 at the end of the fade-out transition the output video will be filled with the
4486 selected @option{color}.
4487 If both duration and nb_frames are specified, duration is used. Default is 0.
4490 Specify the color of the fade. Default is "black".
4493 @subsection Examples
4497 Fade in the first 30 frames of video:
4502 The command above is equivalent to:
4508 Fade out the last 45 frames of a 200-frame video:
4511 fade=type=out:start_frame=155:nb_frames=45
4515 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4517 fade=in:0:25, fade=out:975:25
4521 Make the first 5 frames yellow, then fade in from frame 5-24:
4523 fade=in:5:20:color=yellow
4527 Fade in alpha over first 25 frames of video:
4529 fade=in:0:25:alpha=1
4533 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4535 fade=t=in:st=5.5:d=0.5
4542 Extract a single field from an interlaced image using stride
4543 arithmetic to avoid wasting CPU time. The output frames are marked as
4546 The filter accepts the following options:
4550 Specify whether to extract the top (if the value is @code{0} or
4551 @code{top}) or the bottom field (if the value is @code{1} or
4557 Field matching filter for inverse telecine. It is meant to reconstruct the
4558 progressive frames from a telecined stream. The filter does not drop duplicated
4559 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4560 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4562 The separation of the field matching and the decimation is notably motivated by
4563 the possibility of inserting a de-interlacing filter fallback between the two.
4564 If the source has mixed telecined and real interlaced content,
4565 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4566 But these remaining combed frames will be marked as interlaced, and thus can be
4567 de-interlaced by a later filter such as @ref{yadif} before decimation.
4569 In addition to the various configuration options, @code{fieldmatch} can take an
4570 optional second stream, activated through the @option{ppsrc} option. If
4571 enabled, the frames reconstruction will be based on the fields and frames from
4572 this second stream. This allows the first input to be pre-processed in order to
4573 help the various algorithms of the filter, while keeping the output lossless
4574 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4575 or brightness/contrast adjustments can help.
4577 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4578 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4579 which @code{fieldmatch} is based on. While the semantic and usage are very
4580 close, some behaviour and options names can differ.
4582 The @ref{decimate} filter currently only works for constant frame rate input.
4583 Do not use @code{fieldmatch} and @ref{decimate} if your input has mixed
4584 telecined and progressive content with changing framerate.
4586 The filter accepts the following options:
4590 Specify the assumed field order of the input stream. Available values are:
4594 Auto detect parity (use FFmpeg's internal parity value).
4596 Assume bottom field first.
4598 Assume top field first.
4601 Note that it is sometimes recommended not to trust the parity announced by the
4604 Default value is @var{auto}.
4607 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4608 sense that it won't risk creating jerkiness due to duplicate frames when
4609 possible, but if there are bad edits or blended fields it will end up
4610 outputting combed frames when a good match might actually exist. On the other
4611 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4612 but will almost always find a good frame if there is one. The other values are
4613 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4614 jerkiness and creating duplicate frames versus finding good matches in sections
4615 with bad edits, orphaned fields, blended fields, etc.
4617 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4619 Available values are:
4623 2-way matching (p/c)
4625 2-way matching, and trying 3rd match if still combed (p/c + n)
4627 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4629 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4630 still combed (p/c + n + u/b)
4632 3-way matching (p/c/n)
4634 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4635 detected as combed (p/c/n + u/b)
4638 The parenthesis at the end indicate the matches that would be used for that
4639 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4642 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4645 Default value is @var{pc_n}.
4648 Mark the main input stream as a pre-processed input, and enable the secondary
4649 input stream as the clean source to pick the fields from. See the filter
4650 introduction for more details. It is similar to the @option{clip2} feature from
4653 Default value is @code{0} (disabled).
4656 Set the field to match from. It is recommended to set this to the same value as
4657 @option{order} unless you experience matching failures with that setting. In
4658 certain circumstances changing the field that is used to match from can have a
4659 large impact on matching performance. Available values are:
4663 Automatic (same value as @option{order}).
4665 Match from the bottom field.
4667 Match from the top field.
4670 Default value is @var{auto}.
4673 Set whether or not chroma is included during the match comparisons. In most
4674 cases it is recommended to leave this enabled. You should set this to @code{0}
4675 only if your clip has bad chroma problems such as heavy rainbowing or other
4676 artifacts. Setting this to @code{0} could also be used to speed things up at
4677 the cost of some accuracy.
4679 Default value is @code{1}.
4683 These define an exclusion band which excludes the lines between @option{y0} and
4684 @option{y1} from being included in the field matching decision. An exclusion
4685 band can be used to ignore subtitles, a logo, or other things that may
4686 interfere with the matching. @option{y0} sets the starting scan line and
4687 @option{y1} sets the ending line; all lines in between @option{y0} and
4688 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4689 @option{y0} and @option{y1} to the same value will disable the feature.
4690 @option{y0} and @option{y1} defaults to @code{0}.
4693 Set the scene change detection threshold as a percentage of maximum change on
4694 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4695 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4696 @option{scthresh} is @code{[0.0, 100.0]}.
4698 Default value is @code{12.0}.
4701 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4702 account the combed scores of matches when deciding what match to use as the
4703 final match. Available values are:
4707 No final matching based on combed scores.
4709 Combed scores are only used when a scene change is detected.
4711 Use combed scores all the time.
4714 Default is @var{sc}.
4717 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4718 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4719 Available values are:
4723 No forced calculation.
4725 Force p/c/n calculations.
4727 Force p/c/n/u/b calculations.
4730 Default value is @var{none}.
4733 This is the area combing threshold used for combed frame detection. This
4734 essentially controls how "strong" or "visible" combing must be to be detected.
4735 Larger values mean combing must be more visible and smaller values mean combing
4736 can be less visible or strong and still be detected. Valid settings are from
4737 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4738 be detected as combed). This is basically a pixel difference value. A good
4739 range is @code{[8, 12]}.
4741 Default value is @code{9}.
4744 Sets whether or not chroma is considered in the combed frame decision. Only
4745 disable this if your source has chroma problems (rainbowing, etc.) that are
4746 causing problems for the combed frame detection with chroma enabled. Actually,
4747 using @option{chroma}=@var{0} is usually more reliable, except for the case
4748 where there is chroma only combing in the source.
4750 Default value is @code{0}.
4754 Respectively set the x-axis and y-axis size of the window used during combed
4755 frame detection. This has to do with the size of the area in which
4756 @option{combpel} pixels are required to be detected as combed for a frame to be
4757 declared combed. See the @option{combpel} parameter description for more info.
4758 Possible values are any number that is a power of 2 starting at 4 and going up
4761 Default value is @code{16}.
4764 The number of combed pixels inside any of the @option{blocky} by
4765 @option{blockx} size blocks on the frame for the frame to be detected as
4766 combed. While @option{cthresh} controls how "visible" the combing must be, this
4767 setting controls "how much" combing there must be in any localized area (a
4768 window defined by the @option{blockx} and @option{blocky} settings) on the
4769 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4770 which point no frames will ever be detected as combed). This setting is known
4771 as @option{MI} in TFM/VFM vocabulary.
4773 Default value is @code{80}.
4776 @anchor{p/c/n/u/b meaning}
4777 @subsection p/c/n/u/b meaning
4779 @subsubsection p/c/n
4781 We assume the following telecined stream:
4784 Top fields: 1 2 2 3 4
4785 Bottom fields: 1 2 3 4 4
4788 The numbers correspond to the progressive frame the fields relate to. Here, the
4789 first two frames are progressive, the 3rd and 4th are combed, and so on.
4791 When @code{fieldmatch} is configured to run a matching from bottom
4792 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4797 B 1 2 3 4 4 <-- matching reference
4806 As a result of the field matching, we can see that some frames get duplicated.
4807 To perform a complete inverse telecine, you need to rely on a decimation filter
4808 after this operation. See for instance the @ref{decimate} filter.
4810 The same operation now matching from top fields (@option{field}=@var{top})
4815 T 1 2 2 3 4 <-- matching reference
4825 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4826 basically, they refer to the frame and field of the opposite parity:
4829 @item @var{p} matches the field of the opposite parity in the previous frame
4830 @item @var{c} matches the field of the opposite parity in the current frame
4831 @item @var{n} matches the field of the opposite parity in the next frame
4836 The @var{u} and @var{b} matching are a bit special in the sense that they match
4837 from the opposite parity flag. In the following examples, we assume that we are
4838 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4839 'x' is placed above and below each matched fields.
4841 With bottom matching (@option{field}=@var{bottom}):
4846 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4847 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4855 With top matching (@option{field}=@var{top}):
4860 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4861 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4869 @subsection Examples
4871 Simple IVTC of a top field first telecined stream:
4873 fieldmatch=order=tff:combmatch=none, decimate
4876 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4878 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4883 Transform the field order of the input video.
4885 It accepts the following parameters:
4890 The output field order. Valid values are @var{tff} for top field first or @var{bff}
4891 for bottom field first.
4894 The default value is @samp{tff}.
4896 The transformation is done by shifting the picture content up or down
4897 by one line, and filling the remaining line with appropriate picture content.
4898 This method is consistent with most broadcast field order converters.
4900 If the input video is not flagged as being interlaced, or it is already
4901 flagged as being of the required output field order, then this filter does
4902 not alter the incoming video.
4904 It is very useful when converting to or from PAL DV material,
4905 which is bottom field first.
4909 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4914 Buffer input images and send them when they are requested.
4916 It is mainly useful when auto-inserted by the libavfilter
4919 It does not take parameters.
4924 Convert the input video to one of the specified pixel formats.
4925 Libavfilter will try to pick one that is suitable as input to
4928 It accepts the following parameters:
4932 A '|'-separated list of pixel format names, such as
4933 "pix_fmts=yuv420p|monow|rgb24".
4937 @subsection Examples
4941 Convert the input video to the @var{yuv420p} format
4943 format=pix_fmts=yuv420p
4946 Convert the input video to any of the formats in the list
4948 format=pix_fmts=yuv420p|yuv444p|yuv410p
4955 Convert the video to specified constant frame rate by duplicating or dropping
4956 frames as necessary.
4958 It accepts the following parameters:
4962 The desired output frame rate. The default is @code{25}.
4967 Possible values are:
4970 zero round towards 0
4974 round towards -infinity
4976 round towards +infinity
4980 The default is @code{near}.
4983 Assume the first PTS should be the given value, in seconds. This allows for
4984 padding/trimming at the start of stream. By default, no assumption is made
4985 about the first frame's expected PTS, so no padding or trimming is done.
4986 For example, this could be set to 0 to pad the beginning with duplicates of
4987 the first frame if a video stream starts after the audio stream or to trim any
4988 frames with a negative PTS.
4992 Alternatively, the options can be specified as a flat string:
4993 @var{fps}[:@var{round}].
4995 See also the @ref{setpts} filter.
4997 @subsection Examples
5001 A typical usage in order to set the fps to 25:
5007 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
5009 fps=fps=film:round=near
5015 Pack two different video streams into a stereoscopic video, setting proper
5016 metadata on supported codecs. The two views should have the same size and
5017 framerate and processing will stop when the shorter video ends. Please note
5018 that you may conveniently adjust view properties with the @ref{scale} and
5021 It accepts the following parameters:
5025 The desired packing format. Supported values are:
5030 The views are next to each other (default).
5033 The views are on top of each other.
5036 The views are packed by line.
5039 The views are packed by column.
5042 The views are temporally interleaved.
5051 # Convert left and right views into a frame-sequential video
5052 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
5054 # Convert views into a side-by-side video with the same output resolution as the input
5055 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
5060 Select one frame every N-th frame.
5062 This filter accepts the following option:
5065 Select frame after every @code{step} frames.
5066 Allowed values are positive integers higher than 0. Default value is @code{1}.
5072 Apply a frei0r effect to the input video.
5074 To enable the compilation of this filter, you need to install the frei0r
5075 header and configure FFmpeg with @code{--enable-frei0r}.
5077 It accepts the following parameters:
5082 The name of the frei0r effect to load. If the environment variable
5083 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
5084 directories specified by the colon-separated list in @env{FREIOR_PATH}.
5085 Otherwise, the standard frei0r paths are searched, in this order:
5086 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
5087 @file{/usr/lib/frei0r-1/}.
5090 A '|'-separated list of parameters to pass to the frei0r effect.
5094 A frei0r effect parameter can be a boolean (its value is either
5095 "y" or "n"), a double, a color (specified as
5096 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
5097 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
5098 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
5099 @var{X} and @var{Y} are floating point numbers) and/or a string.
5101 The number and types of parameters depend on the loaded effect. If an
5102 effect parameter is not specified, the default value is set.
5104 @subsection Examples
5108 Apply the distort0r effect, setting the first two double parameters:
5110 frei0r=filter_name=distort0r:filter_params=0.5|0.01
5114 Apply the colordistance effect, taking a color as the first parameter:
5116 frei0r=colordistance:0.2/0.3/0.4
5117 frei0r=colordistance:violet
5118 frei0r=colordistance:0x112233
5122 Apply the perspective effect, specifying the top left and top right image
5125 frei0r=perspective:0.2/0.2|0.8/0.2
5129 For more information, see
5130 @url{http://frei0r.dyne.org}
5134 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
5136 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
5137 processing filter, one of them is performed once per block, not per pixel.
5138 This allows for much higher speed.
5140 The filter accepts the following options:
5144 Set quality. This option defines the number of levels for averaging. It accepts
5145 an integer in the range 4-5. Default value is @code{4}.
5148 Force a constant quantization parameter. It accepts an integer in range 0-63.
5149 If not set, the filter will use the QP from the video stream (if available).
5152 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
5153 more details but also more artifacts, while higher values make the image smoother
5154 but also blurrier. Default value is @code{0} − PSNR optimal.
5157 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
5158 option may cause flicker since the B-Frames have often larger QP. Default is
5159 @code{0} (not enabled).
5165 The filter accepts the following options:
5169 Set the luminance expression.
5171 Set the chrominance blue expression.
5173 Set the chrominance red expression.
5175 Set the alpha expression.
5177 Set the red expression.
5179 Set the green expression.
5181 Set the blue expression.
5184 The colorspace is selected according to the specified options. If one
5185 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
5186 options is specified, the filter will automatically select a YCbCr
5187 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
5188 @option{blue_expr} options is specified, it will select an RGB
5191 If one of the chrominance expression is not defined, it falls back on the other
5192 one. If no alpha expression is specified it will evaluate to opaque value.
5193 If none of chrominance expressions are specified, they will evaluate
5194 to the luminance expression.
5196 The expressions can use the following variables and functions:
5200 The sequential number of the filtered frame, starting from @code{0}.
5204 The coordinates of the current sample.
5208 The width and height of the image.
5212 Width and height scale depending on the currently filtered plane. It is the
5213 ratio between the corresponding luma plane number of pixels and the current
5214 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
5215 @code{0.5,0.5} for chroma planes.
5218 Time of the current frame, expressed in seconds.
5221 Return the value of the pixel at location (@var{x},@var{y}) of the current
5225 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
5229 Return the value of the pixel at location (@var{x},@var{y}) of the
5230 blue-difference chroma plane. Return 0 if there is no such plane.
5233 Return the value of the pixel at location (@var{x},@var{y}) of the
5234 red-difference chroma plane. Return 0 if there is no such plane.
5239 Return the value of the pixel at location (@var{x},@var{y}) of the
5240 red/green/blue component. Return 0 if there is no such component.
5243 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
5244 plane. Return 0 if there is no such plane.
5247 For functions, if @var{x} and @var{y} are outside the area, the value will be
5248 automatically clipped to the closer edge.
5250 @subsection Examples
5254 Flip the image horizontally:
5260 Generate a bidimensional sine wave, with angle @code{PI/3} and a
5261 wavelength of 100 pixels:
5263 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
5267 Generate a fancy enigmatic moving light:
5269 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
5273 Generate a quick emboss effect:
5275 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
5279 Modify RGB components depending on pixel position:
5281 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
5285 Create a radial gradient that is the same size as the input (also see
5286 the @ref{vignette} filter):
5288 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
5292 Create a linear gradient to use as a mask for another filter, then
5293 compose with @ref{overlay}. In this example the video will gradually
5294 become more blurry from the top to the bottom of the y-axis as defined
5295 by the linear gradient:
5297 ffmpeg -i input.mp4 -filter_complex "geq=lum=255*(Y/H),format=gray[grad];[0:v]boxblur=4[blur];[blur][grad]alphamerge[alpha];[0:v][alpha]overlay" output.mp4
5303 Fix the banding artifacts that are sometimes introduced into nearly flat
5304 regions by truncation to 8bit color depth.
5305 Interpolate the gradients that should go where the bands are, and
5308 It is designed for playback only. Do not use it prior to
5309 lossy compression, because compression tends to lose the dither and
5310 bring back the bands.
5312 It accepts the following parameters:
5317 The maximum amount by which the filter will change any one pixel. This is also
5318 the threshold for detecting nearly flat regions. Acceptable values range from
5319 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
5323 The neighborhood to fit the gradient to. A larger radius makes for smoother
5324 gradients, but also prevents the filter from modifying the pixels near detailed
5325 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
5326 values will be clipped to the valid range.
5330 Alternatively, the options can be specified as a flat string:
5331 @var{strength}[:@var{radius}]
5333 @subsection Examples
5337 Apply the filter with a @code{3.5} strength and radius of @code{8}:
5343 Specify radius, omitting the strength (which will fall-back to the default
5354 Apply a Hald CLUT to a video stream.
5356 First input is the video stream to process, and second one is the Hald CLUT.
5357 The Hald CLUT input can be a simple picture or a complete video stream.
5359 The filter accepts the following options:
5363 Force termination when the shortest input terminates. Default is @code{0}.
5365 Continue applying the last CLUT after the end of the stream. A value of
5366 @code{0} disable the filter after the last frame of the CLUT is reached.
5367 Default is @code{1}.
5370 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
5371 filters share the same internals).
5373 More information about the Hald CLUT can be found on Eskil Steenberg's website
5374 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
5376 @subsection Workflow examples
5378 @subsubsection Hald CLUT video stream
5380 Generate an identity Hald CLUT stream altered with various effects:
5382 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
5385 Note: make sure you use a lossless codec.
5387 Then use it with @code{haldclut} to apply it on some random stream:
5389 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
5392 The Hald CLUT will be applied to the 10 first seconds (duration of
5393 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
5394 to the remaining frames of the @code{mandelbrot} stream.
5396 @subsubsection Hald CLUT with preview
5398 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
5399 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
5400 biggest possible square starting at the top left of the picture. The remaining
5401 padding pixels (bottom or right) will be ignored. This area can be used to add
5402 a preview of the Hald CLUT.
5404 Typically, the following generated Hald CLUT will be supported by the
5405 @code{haldclut} filter:
5408 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
5409 pad=iw+320 [padded_clut];
5410 smptebars=s=320x256, split [a][b];
5411 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
5412 [main][b] overlay=W-320" -frames:v 1 clut.png
5415 It contains the original and a preview of the effect of the CLUT: SMPTE color
5416 bars are displayed on the right-top, and below the same color bars processed by
5419 Then, the effect of this Hald CLUT can be visualized with:
5421 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
5426 Flip the input video horizontally.
5428 For example, to horizontally flip the input video with @command{ffmpeg}:
5430 ffmpeg -i in.avi -vf "hflip" out.avi
5434 This filter applies a global color histogram equalization on a
5437 It can be used to correct video that has a compressed range of pixel
5438 intensities. The filter redistributes the pixel intensities to
5439 equalize their distribution across the intensity range. It may be
5440 viewed as an "automatically adjusting contrast filter". This filter is
5441 useful only for correcting degraded or poorly captured source
5444 The filter accepts the following options:
5448 Determine the amount of equalization to be applied. As the strength
5449 is reduced, the distribution of pixel intensities more-and-more
5450 approaches that of the input frame. The value must be a float number
5451 in the range [0,1] and defaults to 0.200.
5454 Set the maximum intensity that can generated and scale the output
5455 values appropriately. The strength should be set as desired and then
5456 the intensity can be limited if needed to avoid washing-out. The value
5457 must be a float number in the range [0,1] and defaults to 0.210.
5460 Set the antibanding level. If enabled the filter will randomly vary
5461 the luminance of output pixels by a small amount to avoid banding of
5462 the histogram. Possible values are @code{none}, @code{weak} or
5463 @code{strong}. It defaults to @code{none}.
5468 Compute and draw a color distribution histogram for the input video.
5470 The computed histogram is a representation of the color component
5471 distribution in an image.
5473 The filter accepts the following options:
5479 It accepts the following values:
5482 Standard histogram that displays the color components distribution in an
5483 image. Displays color graph for each color component. Shows distribution of
5484 the Y, U, V, A or R, G, B components, depending on input format, in the
5485 current frame. Below each graph a color component scale meter is shown.
5488 Displays chroma values (U/V color placement) in a two dimensional
5489 graph (which is called a vectorscope). The brighter a pixel in the
5490 vectorscope, the more pixels of the input frame correspond to that pixel
5491 (i.e., more pixels have this chroma value). The V component is displayed on
5492 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5493 side being V = 255. The U component is displayed on the vertical (Y) axis,
5494 with the top representing U = 0 and the bottom representing U = 255.
5496 The position of a white pixel in the graph corresponds to the chroma value of
5497 a pixel of the input clip. The graph can therefore be used to read the hue
5498 (color flavor) and the saturation (the dominance of the hue in the color). As
5499 the hue of a color changes, it moves around the square. At the center of the
5500 square the saturation is zero, which means that the corresponding pixel has no
5501 color. If the amount of a specific color is increased (while leaving the other
5502 colors unchanged) the saturation increases, and the indicator moves towards
5503 the edge of the square.
5506 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5510 Per row/column color component graph. In row mode, the graph on the left side
5511 represents color component value 0 and the right side represents value = 255.
5512 In column mode, the top side represents color component value = 0 and bottom
5513 side represents value = 255.
5515 Default value is @code{levels}.
5518 Set height of level in @code{levels}. Default value is @code{200}.
5519 Allowed range is [50, 2048].
5522 Set height of color scale in @code{levels}. Default value is @code{12}.
5523 Allowed range is [0, 40].
5526 Set step for @code{waveform} mode. Smaller values are useful to find out how
5527 many values of the same luminance are distributed across input rows/columns.
5528 Default value is @code{10}. Allowed range is [1, 255].
5531 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5532 Default is @code{row}.
5534 @item waveform_mirror
5535 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5536 means mirrored. In mirrored mode, higher values will be represented on the left
5537 side for @code{row} mode and at the top for @code{column} mode. Default is
5538 @code{0} (unmirrored).
5541 Set display mode for @code{waveform} and @code{levels}.
5542 It accepts the following values:
5545 Display separate graph for the color components side by side in
5546 @code{row} waveform mode or one below the other in @code{column} waveform mode
5547 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5548 per color component graphs are placed below each other.
5550 Using this display mode in @code{waveform} histogram mode makes it easy to
5551 spot color casts in the highlights and shadows of an image, by comparing the
5552 contours of the top and the bottom graphs of each waveform. Since whites,
5553 grays, and blacks are characterized by exactly equal amounts of red, green,
5554 and blue, neutral areas of the picture should display three waveforms of
5555 roughly equal width/height. If not, the correction is easy to perform by
5556 making level adjustments the three waveforms.
5559 Presents information identical to that in the @code{parade}, except
5560 that the graphs representing color components are superimposed directly
5563 This display mode in @code{waveform} histogram mode makes it easier to spot
5564 relative differences or similarities in overlapping areas of the color
5565 components that are supposed to be identical, such as neutral whites, grays,
5568 Default is @code{parade}.
5571 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5572 Default is @code{linear}.
5575 @subsection Examples
5580 Calculate and draw histogram:
5582 ffplay -i input -vf histogram
5590 This is a high precision/quality 3d denoise filter. It aims to reduce
5591 image noise, producing smooth images and making still images really
5592 still. It should enhance compressibility.
5594 It accepts the following optional parameters:
5598 A non-negative floating point number which specifies spatial luma strength.
5601 @item chroma_spatial
5602 A non-negative floating point number which specifies spatial chroma strength.
5603 It defaults to 3.0*@var{luma_spatial}/4.0.
5606 A floating point number which specifies luma temporal strength. It defaults to
5607 6.0*@var{luma_spatial}/4.0.
5610 A floating point number which specifies chroma temporal strength. It defaults to
5611 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5616 Apply a high-quality magnification filter designed for pixel art. This filter
5617 was originally created by Maxim Stepin.
5619 It accepts the following option:
5623 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
5624 @code{hq3x} and @code{4} for @code{hq4x}.
5625 Default is @code{3}.
5630 Modify the hue and/or the saturation of the input.
5632 It accepts the following parameters:
5636 Specify the hue angle as a number of degrees. It accepts an expression,
5637 and defaults to "0".
5640 Specify the saturation in the [-10,10] range. It accepts an expression and
5644 Specify the hue angle as a number of radians. It accepts an
5645 expression, and defaults to "0".
5648 Specify the brightness in the [-10,10] range. It accepts an expression and
5652 @option{h} and @option{H} are mutually exclusive, and can't be
5653 specified at the same time.
5655 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5656 expressions containing the following constants:
5660 frame count of the input frame starting from 0
5663 presentation timestamp of the input frame expressed in time base units
5666 frame rate of the input video, NAN if the input frame rate is unknown
5669 timestamp expressed in seconds, NAN if the input timestamp is unknown
5672 time base of the input video
5675 @subsection Examples
5679 Set the hue to 90 degrees and the saturation to 1.0:
5685 Same command but expressing the hue in radians:
5691 Rotate hue and make the saturation swing between 0
5692 and 2 over a period of 1 second:
5694 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5698 Apply a 3 seconds saturation fade-in effect starting at 0:
5703 The general fade-in expression can be written as:
5705 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5709 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5711 hue="s=max(0\, min(1\, (8-t)/3))"
5714 The general fade-out expression can be written as:
5716 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5721 @subsection Commands
5723 This filter supports the following commands:
5729 Modify the hue and/or the saturation and/or brightness of the input video.
5730 The command accepts the same syntax of the corresponding option.
5732 If the specified expression is not valid, it is kept at its current
5738 Detect video interlacing type.
5740 This filter tries to detect if the input frames as interlaced, progressive,
5741 top or bottom field first. It will also try and detect fields that are
5742 repeated between adjacent frames (a sign of telecine).
5744 Single frame detection considers only immediately adjacent frames when classifying each frame.
5745 Multiple frame detection incorporates the classification history of previous frames.
5747 The filter will log these metadata values:
5750 @item single.current_frame
5751 Detected type of current frame using single-frame detection. One of:
5752 ``tff'' (top field first), ``bff'' (bottom field first),
5753 ``progressive'', or ``undetermined''
5756 Cumulative number of frames detected as top field first using single-frame detection.
5759 Cumulative number of frames detected as top field first using multiple-frame detection.
5762 Cumulative number of frames detected as bottom field first using single-frame detection.
5764 @item multiple.current_frame
5765 Detected type of current frame using multiple-frame detection. One of:
5766 ``tff'' (top field first), ``bff'' (bottom field first),
5767 ``progressive'', or ``undetermined''
5770 Cumulative number of frames detected as bottom field first using multiple-frame detection.
5772 @item single.progressive
5773 Cumulative number of frames detected as progressive using single-frame detection.
5775 @item multiple.progressive
5776 Cumulative number of frames detected as progressive using multiple-frame detection.
5778 @item single.undetermined
5779 Cumulative number of frames that could not be classified using single-frame detection.
5781 @item multiple.undetermined
5782 Cumulative number of frames that could not be classified using multiple-frame detection.
5784 @item repeated.current_frame
5785 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
5787 @item repeated.neither
5788 Cumulative number of frames with no repeated field.
5791 Cumulative number of frames with the top field repeated from the previous frame's top field.
5793 @item repeated.bottom
5794 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
5797 The filter accepts the following options:
5801 Set interlacing threshold.
5803 Set progressive threshold.
5805 Threshold for repeated field detection.
5807 Number of frames after which a given frame's contribution to the
5808 statistics is halved (i.e., it contributes only 0.5 to it's
5809 classification). The default of 0 means that all frames seen are given
5810 full weight of 1.0 forever.
5811 @item analyze_interlaced_flag
5812 When this is not 0 then idet will use the specified number of frames to determine
5813 if the interlaced flag is accurate, it will not count undetermined frames.
5814 If the flag is found to be accurate it will be used without any further
5815 computations, if it is found to be inaccuarte it will be cleared without any
5816 further computations. This allows inserting the idet filter as a low computational
5817 method to clean up the interlaced flag
5822 Deinterleave or interleave fields.
5824 This filter allows one to process interlaced images fields without
5825 deinterlacing them. Deinterleaving splits the input frame into 2
5826 fields (so called half pictures). Odd lines are moved to the top
5827 half of the output image, even lines to the bottom half.
5828 You can process (filter) them independently and then re-interleave them.
5830 The filter accepts the following options:
5834 @item chroma_mode, c
5836 Available values for @var{luma_mode}, @var{chroma_mode} and
5837 @var{alpha_mode} are:
5843 @item deinterleave, d
5844 Deinterleave fields, placing one above the other.
5847 Interleave fields. Reverse the effect of deinterleaving.
5849 Default value is @code{none}.
5852 @item chroma_swap, cs
5853 @item alpha_swap, as
5854 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5859 Simple interlacing filter from progressive contents. This interleaves upper (or
5860 lower) lines from odd frames with lower (or upper) lines from even frames,
5861 halving the frame rate and preserving image height.
5864 Original Original New Frame
5865 Frame 'j' Frame 'j+1' (tff)
5866 ========== =========== ==================
5867 Line 0 --------------------> Frame 'j' Line 0
5868 Line 1 Line 1 ----> Frame 'j+1' Line 1
5869 Line 2 ---------------------> Frame 'j' Line 2
5870 Line 3 Line 3 ----> Frame 'j+1' Line 3
5872 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5875 It accepts the following optional parameters:
5879 This determines whether the interlaced frame is taken from the even
5880 (tff - default) or odd (bff) lines of the progressive frame.
5883 Enable (default) or disable the vertical lowpass filter to avoid twitter
5884 interlacing and reduce moire patterns.
5889 Deinterlace input video by applying Donald Graft's adaptive kernel
5890 deinterling. Work on interlaced parts of a video to produce
5893 The description of the accepted parameters follows.
5897 Set the threshold which affects the filter's tolerance when
5898 determining if a pixel line must be processed. It must be an integer
5899 in the range [0,255] and defaults to 10. A value of 0 will result in
5900 applying the process on every pixels.
5903 Paint pixels exceeding the threshold value to white if set to 1.
5907 Set the fields order. Swap fields if set to 1, leave fields alone if
5911 Enable additional sharpening if set to 1. Default is 0.
5914 Enable twoway sharpening if set to 1. Default is 0.
5917 @subsection Examples
5921 Apply default values:
5923 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5927 Enable additional sharpening:
5933 Paint processed pixels in white:
5939 @section lenscorrection
5941 Correct radial lens distortion
5943 This filter can be used to correct for radial distortion as can result from the use
5944 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
5945 one can use tools available for example as part of opencv or simply trial-and-error.
5946 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
5947 and extract the k1 and k2 coefficients from the resulting matrix.
5949 Note that effectively the same filter is available in the open-source tools Krita and
5950 Digikam from the KDE project.
5952 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
5953 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
5954 brightness distribution, so you may want to use both filters together in certain
5955 cases, though you will have to take care of ordering, i.e. whether vignetting should
5956 be applied before or after lens correction.
5960 The filter accepts the following options:
5964 Relative x-coordinate of the focal point of the image, and thereby the center of the
5965 distortion. This value has a range [0,1] and is expressed as fractions of the image
5968 Relative y-coordinate of the focal point of the image, and thereby the center of the
5969 distortion. This value has a range [0,1] and is expressed as fractions of the image
5972 Coefficient of the quadratic correction term. 0.5 means no correction.
5974 Coefficient of the double quadratic correction term. 0.5 means no correction.
5977 The formula that generates the correction is:
5979 @var{r_src} = @var{r_tgt} * (1 + @var{k1} * (@var{r_tgt} / @var{r_0})^2 + @var{k2} * (@var{r_tgt} / @var{r_0})^4)
5981 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
5982 distances from the focal point in the source and target images, respectively.
5987 Apply a 3D LUT to an input video.
5989 The filter accepts the following options:
5993 Set the 3D LUT file name.
5995 Currently supported formats:
6007 Select interpolation mode.
6009 Available values are:
6013 Use values from the nearest defined point.
6015 Interpolate values using the 8 points defining a cube.
6017 Interpolate values using a tetrahedron.
6021 @section lut, lutrgb, lutyuv
6023 Compute a look-up table for binding each pixel component input value
6024 to an output value, and apply it to the input video.
6026 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
6027 to an RGB input video.
6029 These filters accept the following parameters:
6032 set first pixel component expression
6034 set second pixel component expression
6036 set third pixel component expression
6038 set fourth pixel component expression, corresponds to the alpha component
6041 set red component expression
6043 set green component expression
6045 set blue component expression
6047 alpha component expression
6050 set Y/luminance component expression
6052 set U/Cb component expression
6054 set V/Cr component expression
6057 Each of them specifies the expression to use for computing the lookup table for
6058 the corresponding pixel component values.
6060 The exact component associated to each of the @var{c*} options depends on the
6063 The @var{lut} filter requires either YUV or RGB pixel formats in input,
6064 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
6066 The expressions can contain the following constants and functions:
6071 The input width and height.
6074 The input value for the pixel component.
6077 The input value, clipped to the @var{minval}-@var{maxval} range.
6080 The maximum value for the pixel component.
6083 The minimum value for the pixel component.
6086 The negated value for the pixel component value, clipped to the
6087 @var{minval}-@var{maxval} range; it corresponds to the expression
6088 "maxval-clipval+minval".
6091 The computed value in @var{val}, clipped to the
6092 @var{minval}-@var{maxval} range.
6094 @item gammaval(gamma)
6095 The computed gamma correction value of the pixel component value,
6096 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
6098 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
6102 All expressions default to "val".
6104 @subsection Examples
6110 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
6111 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
6114 The above is the same as:
6116 lutrgb="r=negval:g=negval:b=negval"
6117 lutyuv="y=negval:u=negval:v=negval"
6127 Remove chroma components, turning the video into a graytone image:
6129 lutyuv="u=128:v=128"
6133 Apply a luma burning effect:
6139 Remove green and blue components:
6145 Set a constant alpha channel value on input:
6147 format=rgba,lutrgb=a="maxval-minval/2"
6151 Correct luminance gamma by a factor of 0.5:
6153 lutyuv=y=gammaval(0.5)
6157 Discard least significant bits of luma:
6159 lutyuv=y='bitand(val, 128+64+32)'
6163 @section mergeplanes
6165 Merge color channel components from several video streams.
6167 The filter accepts up to 4 input streams, and merge selected input
6168 planes to the output video.
6170 This filter accepts the following options:
6173 Set input to output plane mapping. Default is @code{0}.
6175 The mappings is specified as a bitmap. It should be specified as a
6176 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
6177 mapping for the first plane of the output stream. 'A' sets the number of
6178 the input stream to use (from 0 to 3), and 'a' the plane number of the
6179 corresponding input to use (from 0 to 3). The rest of the mappings is
6180 similar, 'Bb' describes the mapping for the output stream second
6181 plane, 'Cc' describes the mapping for the output stream third plane and
6182 'Dd' describes the mapping for the output stream fourth plane.
6185 Set output pixel format. Default is @code{yuva444p}.
6188 @subsection Examples
6192 Merge three gray video streams of same width and height into single video stream:
6194 [a0][a1][a2]mergeplanes=0x001020:yuv444p
6198 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
6200 [a0][a1]mergeplanes=0x00010210:yuva444p
6204 Swap Y and A plane in yuva444p stream:
6206 format=yuva444p,mergeplanes=0x03010200:yuva444p
6210 Swap U and V plane in yuv420p stream:
6212 format=yuv420p,mergeplanes=0x000201:yuv420p
6216 Cast a rgb24 clip to yuv444p:
6218 format=rgb24,mergeplanes=0x000102:yuv444p
6224 Apply motion-compensation deinterlacing.
6226 It needs one field per frame as input and must thus be used together
6227 with yadif=1/3 or equivalent.
6229 This filter accepts the following options:
6232 Set the deinterlacing mode.
6234 It accepts one of the following values:
6239 use iterative motion estimation
6241 like @samp{slow}, but use multiple reference frames.
6243 Default value is @samp{fast}.
6246 Set the picture field parity assumed for the input video. It must be
6247 one of the following values:
6251 assume top field first
6253 assume bottom field first
6256 Default value is @samp{bff}.
6259 Set per-block quantization parameter (QP) used by the internal
6262 Higher values should result in a smoother motion vector field but less
6263 optimal individual vectors. Default value is 1.
6268 Drop frames that do not differ greatly from the previous frame in
6269 order to reduce frame rate.
6271 The main use of this filter is for very-low-bitrate encoding
6272 (e.g. streaming over dialup modem), but it could in theory be used for
6273 fixing movies that were inverse-telecined incorrectly.
6275 A description of the accepted options follows.
6279 Set the maximum number of consecutive frames which can be dropped (if
6280 positive), or the minimum interval between dropped frames (if
6281 negative). If the value is 0, the frame is dropped unregarding the
6282 number of previous sequentially dropped frames.
6289 Set the dropping threshold values.
6291 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
6292 represent actual pixel value differences, so a threshold of 64
6293 corresponds to 1 unit of difference for each pixel, or the same spread
6294 out differently over the block.
6296 A frame is a candidate for dropping if no 8x8 blocks differ by more
6297 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
6298 meaning the whole image) differ by more than a threshold of @option{lo}.
6300 Default value for @option{hi} is 64*12, default value for @option{lo} is
6301 64*5, and default value for @option{frac} is 0.33.
6309 It accepts an integer in input; if non-zero it negates the
6310 alpha component (if available). The default value in input is 0.
6314 Force libavfilter not to use any of the specified pixel formats for the
6315 input to the next filter.
6317 It accepts the following parameters:
6321 A '|'-separated list of pixel format names, such as
6322 apix_fmts=yuv420p|monow|rgb24".
6326 @subsection Examples
6330 Force libavfilter to use a format different from @var{yuv420p} for the
6331 input to the vflip filter:
6333 noformat=pix_fmts=yuv420p,vflip
6337 Convert the input video to any of the formats not contained in the list:
6339 noformat=yuv420p|yuv444p|yuv410p
6345 Add noise on video input frame.
6347 The filter accepts the following options:
6355 Set noise seed for specific pixel component or all pixel components in case
6356 of @var{all_seed}. Default value is @code{123457}.
6358 @item all_strength, alls
6359 @item c0_strength, c0s
6360 @item c1_strength, c1s
6361 @item c2_strength, c2s
6362 @item c3_strength, c3s
6363 Set noise strength for specific pixel component or all pixel components in case
6364 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
6366 @item all_flags, allf
6371 Set pixel component flags or set flags for all components if @var{all_flags}.
6372 Available values for component flags are:
6375 averaged temporal noise (smoother)
6377 mix random noise with a (semi)regular pattern
6379 temporal noise (noise pattern changes between frames)
6381 uniform noise (gaussian otherwise)
6385 @subsection Examples
6387 Add temporal and uniform noise to input video:
6389 noise=alls=20:allf=t+u
6394 Pass the video source unchanged to the output.
6398 Apply a video transform using libopencv.
6400 To enable this filter, install the libopencv library and headers and
6401 configure FFmpeg with @code{--enable-libopencv}.
6403 It accepts the following parameters:
6408 The name of the libopencv filter to apply.
6411 The parameters to pass to the libopencv filter. If not specified, the default
6416 Refer to the official libopencv documentation for more precise
6418 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
6420 Several libopencv filters are supported; see the following subsections.
6425 Dilate an image by using a specific structuring element.
6426 It corresponds to the libopencv function @code{cvDilate}.
6428 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
6430 @var{struct_el} represents a structuring element, and has the syntax:
6431 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
6433 @var{cols} and @var{rows} represent the number of columns and rows of
6434 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
6435 point, and @var{shape} the shape for the structuring element. @var{shape}
6436 must be "rect", "cross", "ellipse", or "custom".
6438 If the value for @var{shape} is "custom", it must be followed by a
6439 string of the form "=@var{filename}". The file with name
6440 @var{filename} is assumed to represent a binary image, with each
6441 printable character corresponding to a bright pixel. When a custom
6442 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
6443 or columns and rows of the read file are assumed instead.
6445 The default value for @var{struct_el} is "3x3+0x0/rect".
6447 @var{nb_iterations} specifies the number of times the transform is
6448 applied to the image, and defaults to 1.
6452 # Use the default values
6455 # Dilate using a structuring element with a 5x5 cross, iterating two times
6456 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
6458 # Read the shape from the file diamond.shape, iterating two times.
6459 # The file diamond.shape may contain a pattern of characters like this
6465 # The specified columns and rows are ignored
6466 # but the anchor point coordinates are not
6467 ocv=dilate:0x0+2x2/custom=diamond.shape|2
6472 Erode an image by using a specific structuring element.
6473 It corresponds to the libopencv function @code{cvErode}.
6475 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
6476 with the same syntax and semantics as the @ref{dilate} filter.
6480 Smooth the input video.
6482 The filter takes the following parameters:
6483 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
6485 @var{type} is the type of smooth filter to apply, and must be one of
6486 the following values: "blur", "blur_no_scale", "median", "gaussian",
6487 or "bilateral". The default value is "gaussian".
6489 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
6490 depend on the smooth type. @var{param1} and
6491 @var{param2} accept integer positive values or 0. @var{param3} and
6492 @var{param4} accept floating point values.
6494 The default value for @var{param1} is 3. The default value for the
6495 other parameters is 0.
6497 These parameters correspond to the parameters assigned to the
6498 libopencv function @code{cvSmooth}.
6503 Overlay one video on top of another.
6505 It takes two inputs and has one output. The first input is the "main"
6506 video on which the second input is overlaid.
6508 It accepts the following parameters:
6510 A description of the accepted options follows.
6515 Set the expression for the x and y coordinates of the overlaid video
6516 on the main video. Default value is "0" for both expressions. In case
6517 the expression is invalid, it is set to a huge value (meaning that the
6518 overlay will not be displayed within the output visible area).
6521 The action to take when EOF is encountered on the secondary input; it accepts
6522 one of the following values:
6526 Repeat the last frame (the default).
6530 Pass the main input through.
6534 Set when the expressions for @option{x}, and @option{y} are evaluated.
6536 It accepts the following values:
6539 only evaluate expressions once during the filter initialization or
6540 when a command is processed
6543 evaluate expressions for each incoming frame
6546 Default value is @samp{frame}.
6549 If set to 1, force the output to terminate when the shortest input
6550 terminates. Default value is 0.
6553 Set the format for the output video.
6555 It accepts the following values:
6570 Default value is @samp{yuv420}.
6572 @item rgb @emph{(deprecated)}
6573 If set to 1, force the filter to accept inputs in the RGB
6574 color space. Default value is 0. This option is deprecated, use
6575 @option{format} instead.
6578 If set to 1, force the filter to draw the last overlay frame over the
6579 main input until the end of the stream. A value of 0 disables this
6580 behavior. Default value is 1.
6583 The @option{x}, and @option{y} expressions can contain the following
6589 The main input width and height.
6593 The overlay input width and height.
6597 The computed values for @var{x} and @var{y}. They are evaluated for
6602 horizontal and vertical chroma subsample values of the output
6603 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6607 the number of input frame, starting from 0
6610 the position in the file of the input frame, NAN if unknown
6613 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6617 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6618 when evaluation is done @emph{per frame}, and will evaluate to NAN
6619 when @option{eval} is set to @samp{init}.
6621 Be aware that frames are taken from each input video in timestamp
6622 order, hence, if their initial timestamps differ, it is a good idea
6623 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6624 have them begin in the same zero timestamp, as the example for
6625 the @var{movie} filter does.
6627 You can chain together more overlays but you should test the
6628 efficiency of such approach.
6630 @subsection Commands
6632 This filter supports the following commands:
6636 Modify the x and y of the overlay input.
6637 The command accepts the same syntax of the corresponding option.
6639 If the specified expression is not valid, it is kept at its current
6643 @subsection Examples
6647 Draw the overlay at 10 pixels from the bottom right corner of the main
6650 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6653 Using named options the example above becomes:
6655 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6659 Insert a transparent PNG logo in the bottom left corner of the input,
6660 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6662 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6666 Insert 2 different transparent PNG logos (second logo on bottom
6667 right corner) using the @command{ffmpeg} tool:
6669 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
6673 Add a transparent color layer on top of the main video; @code{WxH}
6674 must specify the size of the main input to the overlay filter:
6676 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6680 Play an original video and a filtered version (here with the deshake
6681 filter) side by side using the @command{ffplay} tool:
6683 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6686 The above command is the same as:
6688 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6692 Make a sliding overlay appearing from the left to the right top part of the
6693 screen starting since time 2:
6695 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6699 Compose output by putting two input videos side to side:
6701 ffmpeg -i left.avi -i right.avi -filter_complex "
6702 nullsrc=size=200x100 [background];
6703 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6704 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6705 [background][left] overlay=shortest=1 [background+left];
6706 [background+left][right] overlay=shortest=1:x=100 [left+right]
6711 Mask 10-20 seconds of a video by applying the delogo filter to a section
6713 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6714 -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]'
6719 Chain several overlays in cascade:
6721 nullsrc=s=200x200 [bg];
6722 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6723 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6724 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6725 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6726 [in3] null, [mid2] overlay=100:100 [out0]
6733 Apply Overcomplete Wavelet denoiser.
6735 The filter accepts the following options:
6741 Larger depth values will denoise lower frequency components more, but
6742 slow down filtering.
6744 Must be an int in the range 8-16, default is @code{8}.
6746 @item luma_strength, ls
6749 Must be a double value in the range 0-1000, default is @code{1.0}.
6751 @item chroma_strength, cs
6752 Set chroma strength.
6754 Must be a double value in the range 0-1000, default is @code{1.0}.
6759 Add paddings to the input image, and place the original input at the
6760 provided @var{x}, @var{y} coordinates.
6762 It accepts the following parameters:
6767 Specify an expression for the size of the output image with the
6768 paddings added. If the value for @var{width} or @var{height} is 0, the
6769 corresponding input size is used for the output.
6771 The @var{width} expression can reference the value set by the
6772 @var{height} expression, and vice versa.
6774 The default value of @var{width} and @var{height} is 0.
6778 Specify the offsets to place the input image at within the padded area,
6779 with respect to the top/left border of the output image.
6781 The @var{x} expression can reference the value set by the @var{y}
6782 expression, and vice versa.
6784 The default value of @var{x} and @var{y} is 0.
6787 Specify the color of the padded area. For the syntax of this option,
6788 check the "Color" section in the ffmpeg-utils manual.
6790 The default value of @var{color} is "black".
6793 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6794 options are expressions containing the following constants:
6799 The input video width and height.
6803 These are the same as @var{in_w} and @var{in_h}.
6807 The output width and height (the size of the padded area), as
6808 specified by the @var{width} and @var{height} expressions.
6812 These are the same as @var{out_w} and @var{out_h}.
6816 The x and y offsets as specified by the @var{x} and @var{y}
6817 expressions, or NAN if not yet specified.
6820 same as @var{iw} / @var{ih}
6823 input sample aspect ratio
6826 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6830 The horizontal and vertical chroma subsample values. For example for the
6831 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6834 @subsection Examples
6838 Add paddings with the color "violet" to the input video. The output video
6839 size is 640x480, and the top-left corner of the input video is placed at
6842 pad=640:480:0:40:violet
6845 The example above is equivalent to the following command:
6847 pad=width=640:height=480:x=0:y=40:color=violet
6851 Pad the input to get an output with dimensions increased by 3/2,
6852 and put the input video at the center of the padded area:
6854 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6858 Pad the input to get a squared output with size equal to the maximum
6859 value between the input width and height, and put the input video at
6860 the center of the padded area:
6862 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6866 Pad the input to get a final w/h ratio of 16:9:
6868 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6872 In case of anamorphic video, in order to set the output display aspect
6873 correctly, it is necessary to use @var{sar} in the expression,
6874 according to the relation:
6876 (ih * X / ih) * sar = output_dar
6877 X = output_dar / sar
6880 Thus the previous example needs to be modified to:
6882 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6886 Double the output size and put the input video in the bottom-right
6887 corner of the output padded area:
6889 pad="2*iw:2*ih:ow-iw:oh-ih"
6893 @section perspective
6895 Correct perspective of video not recorded perpendicular to the screen.
6897 A description of the accepted parameters follows.
6908 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6909 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6910 If the @code{sense} option is set to @code{source}, then the specified points will be sent
6911 to the corners of the destination. If the @code{sense} option is set to @code{destination},
6912 then the corners of the source will be sent to the specified coordinates.
6914 The expressions can use the following variables:
6919 the width and height of video frame.
6923 Set interpolation for perspective correction.
6925 It accepts the following values:
6931 Default value is @samp{linear}.
6934 Set interpretation of coordinate options.
6936 It accepts the following values:
6940 Send point in the source specified by the given coordinates to
6941 the corners of the destination.
6943 @item 1, destination
6945 Send the corners of the source to the point in the destination specified
6946 by the given coordinates.
6948 Default value is @samp{source}.
6954 Delay interlaced video by one field time so that the field order changes.
6956 The intended use is to fix PAL movies that have been captured with the
6957 opposite field order to the film-to-video transfer.
6959 A description of the accepted parameters follows.
6965 It accepts the following values:
6968 Capture field order top-first, transfer bottom-first.
6969 Filter will delay the bottom field.
6972 Capture field order bottom-first, transfer top-first.
6973 Filter will delay the top field.
6976 Capture and transfer with the same field order. This mode only exists
6977 for the documentation of the other options to refer to, but if you
6978 actually select it, the filter will faithfully do nothing.
6981 Capture field order determined automatically by field flags, transfer
6983 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6984 basis using field flags. If no field information is available,
6985 then this works just like @samp{u}.
6988 Capture unknown or varying, transfer opposite.
6989 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6990 analyzing the images and selecting the alternative that produces best
6991 match between the fields.
6994 Capture top-first, transfer unknown or varying.
6995 Filter selects among @samp{t} and @samp{p} using image analysis.
6998 Capture bottom-first, transfer unknown or varying.
6999 Filter selects among @samp{b} and @samp{p} using image analysis.
7002 Capture determined by field flags, transfer unknown or varying.
7003 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
7004 image analysis. If no field information is available, then this works just
7005 like @samp{U}. This is the default mode.
7008 Both capture and transfer unknown or varying.
7009 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
7013 @section pixdesctest
7015 Pixel format descriptor test filter, mainly useful for internal
7016 testing. The output video should be equal to the input video.
7020 format=monow, pixdesctest
7023 can be used to test the monowhite pixel format descriptor definition.
7027 Enable the specified chain of postprocessing subfilters using libpostproc. This
7028 library should be automatically selected with a GPL build (@code{--enable-gpl}).
7029 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
7030 Each subfilter and some options have a short and a long name that can be used
7031 interchangeably, i.e. dr/dering are the same.
7033 The filters accept the following options:
7037 Set postprocessing subfilters string.
7040 All subfilters share common options to determine their scope:
7044 Honor the quality commands for this subfilter.
7047 Do chrominance filtering, too (default).
7050 Do luminance filtering only (no chrominance).
7053 Do chrominance filtering only (no luminance).
7056 These options can be appended after the subfilter name, separated by a '|'.
7058 Available subfilters are:
7061 @item hb/hdeblock[|difference[|flatness]]
7062 Horizontal deblocking filter
7065 Difference factor where higher values mean more deblocking (default: @code{32}).
7067 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7070 @item vb/vdeblock[|difference[|flatness]]
7071 Vertical deblocking filter
7074 Difference factor where higher values mean more deblocking (default: @code{32}).
7076 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7079 @item ha/hadeblock[|difference[|flatness]]
7080 Accurate horizontal deblocking filter
7083 Difference factor where higher values mean more deblocking (default: @code{32}).
7085 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7088 @item va/vadeblock[|difference[|flatness]]
7089 Accurate vertical deblocking filter
7092 Difference factor where higher values mean more deblocking (default: @code{32}).
7094 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7098 The horizontal and vertical deblocking filters share the difference and
7099 flatness values so you cannot set different horizontal and vertical
7104 Experimental horizontal deblocking filter
7107 Experimental vertical deblocking filter
7112 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
7115 larger -> stronger filtering
7117 larger -> stronger filtering
7119 larger -> stronger filtering
7122 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
7125 Stretch luminance to @code{0-255}.
7128 @item lb/linblenddeint
7129 Linear blend deinterlacing filter that deinterlaces the given block by
7130 filtering all lines with a @code{(1 2 1)} filter.
7132 @item li/linipoldeint
7133 Linear interpolating deinterlacing filter that deinterlaces the given block by
7134 linearly interpolating every second line.
7136 @item ci/cubicipoldeint
7137 Cubic interpolating deinterlacing filter deinterlaces the given block by
7138 cubically interpolating every second line.
7140 @item md/mediandeint
7141 Median deinterlacing filter that deinterlaces the given block by applying a
7142 median filter to every second line.
7144 @item fd/ffmpegdeint
7145 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
7146 second line with a @code{(-1 4 2 4 -1)} filter.
7149 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
7150 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
7152 @item fq/forceQuant[|quantizer]
7153 Overrides the quantizer table from the input with the constant quantizer you
7161 Default pp filter combination (@code{hb|a,vb|a,dr|a})
7164 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
7167 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
7170 @subsection Examples
7174 Apply horizontal and vertical deblocking, deringing and automatic
7175 brightness/contrast:
7181 Apply default filters without brightness/contrast correction:
7187 Apply default filters and temporal denoiser:
7189 pp=default/tmpnoise|1|2|3
7193 Apply deblocking on luminance only, and switch vertical deblocking on or off
7194 automatically depending on available CPU time:
7201 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
7202 similar to spp = 6 with 7 point DCT, where only the center sample is
7205 The filter accepts the following options:
7209 Force a constant quantization parameter. It accepts an integer in range
7210 0 to 63. If not set, the filter will use the QP from the video stream
7214 Set thresholding mode. Available modes are:
7218 Set hard thresholding.
7220 Set soft thresholding (better de-ringing effect, but likely blurrier).
7222 Set medium thresholding (good results, default).
7228 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
7229 Ratio) between two input videos.
7231 This filter takes in input two input videos, the first input is
7232 considered the "main" source and is passed unchanged to the
7233 output. The second input is used as a "reference" video for computing
7236 Both video inputs must have the same resolution and pixel format for
7237 this filter to work correctly. Also it assumes that both inputs
7238 have the same number of frames, which are compared one by one.
7240 The obtained average PSNR is printed through the logging system.
7242 The filter stores the accumulated MSE (mean squared error) of each
7243 frame, and at the end of the processing it is averaged across all frames
7244 equally, and the following formula is applied to obtain the PSNR:
7247 PSNR = 10*log10(MAX^2/MSE)
7250 Where MAX is the average of the maximum values of each component of the
7253 The description of the accepted parameters follows.
7257 If specified the filter will use the named file to save the PSNR of
7258 each individual frame.
7261 The file printed if @var{stats_file} is selected, contains a sequence of
7262 key/value pairs of the form @var{key}:@var{value} for each compared
7265 A description of each shown parameter follows:
7269 sequential number of the input frame, starting from 1
7272 Mean Square Error pixel-by-pixel average difference of the compared
7273 frames, averaged over all the image components.
7275 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
7276 Mean Square Error pixel-by-pixel average difference of the compared
7277 frames for the component specified by the suffix.
7279 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
7280 Peak Signal to Noise ratio of the compared frames for the component
7281 specified by the suffix.
7286 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
7287 [main][ref] psnr="stats_file=stats.log" [out]
7290 On this example the input file being processed is compared with the
7291 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
7292 is stored in @file{stats.log}.
7297 Pulldown reversal (inverse telecine) filter, capable of handling mixed
7298 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
7301 The pullup filter is designed to take advantage of future context in making
7302 its decisions. This filter is stateless in the sense that it does not lock
7303 onto a pattern to follow, but it instead looks forward to the following
7304 fields in order to identify matches and rebuild progressive frames.
7306 To produce content with an even framerate, insert the fps filter after
7307 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
7308 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
7310 The filter accepts the following options:
7317 These options set the amount of "junk" to ignore at the left, right, top, and
7318 bottom of the image, respectively. Left and right are in units of 8 pixels,
7319 while top and bottom are in units of 2 lines.
7320 The default is 8 pixels on each side.
7323 Set the strict breaks. Setting this option to 1 will reduce the chances of
7324 filter generating an occasional mismatched frame, but it may also cause an
7325 excessive number of frames to be dropped during high motion sequences.
7326 Conversely, setting it to -1 will make filter match fields more easily.
7327 This may help processing of video where there is slight blurring between
7328 the fields, but may also cause there to be interlaced frames in the output.
7329 Default value is @code{0}.
7332 Set the metric plane to use. It accepts the following values:
7338 Use chroma blue plane.
7341 Use chroma red plane.
7344 This option may be set to use chroma plane instead of the default luma plane
7345 for doing filter's computations. This may improve accuracy on very clean
7346 source material, but more likely will decrease accuracy, especially if there
7347 is chroma noise (rainbow effect) or any grayscale video.
7348 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
7349 load and make pullup usable in realtime on slow machines.
7352 For best results (without duplicated frames in the output file) it is
7353 necessary to change the output frame rate. For example, to inverse
7354 telecine NTSC input:
7356 ffmpeg -i input -vf pullup -r 24000/1001 ...
7361 Change video quantization parameters (QP).
7363 The filter accepts the following option:
7367 Set expression for quantization parameter.
7370 The expression is evaluated through the eval API and can contain, among others,
7371 the following constants:
7375 1 if index is not 129, 0 otherwise.
7378 Sequentional index starting from -129 to 128.
7381 @subsection Examples
7393 Suppress a TV station logo, using an image file to determine which
7394 pixels comprise the logo. It works by filling in the pixels that
7395 comprise the logo with neighboring pixels.
7397 The filter accepts the following options:
7401 Set the filter bitmap file, which can be any image format supported by
7402 libavformat. The width and height of the image file must match those of the
7403 video stream being processed.
7406 Pixels in the provided bitmap image with a value of zero are not
7407 considered part of the logo, non-zero pixels are considered part of
7408 the logo. If you use white (255) for the logo and black (0) for the
7409 rest, you will be safe. For making the filter bitmap, it is
7410 recommended to take a screen capture of a black frame with the logo
7411 visible, and then using a threshold filter followed by the erode
7412 filter once or twice.
7414 If needed, little splotches can be fixed manually. Remember that if
7415 logo pixels are not covered, the filter quality will be much
7416 reduced. Marking too many pixels as part of the logo does not hurt as
7417 much, but it will increase the amount of blurring needed to cover over
7418 the image and will destroy more information than necessary, and extra
7419 pixels will slow things down on a large logo.
7421 @section repeatfields
7423 This filter uses the repeat_field flag from the Video ES headers and hard repeats
7424 fields based on its value.
7428 Rotate video by an arbitrary angle expressed in radians.
7430 The filter accepts the following options:
7432 A description of the optional parameters follows.
7435 Set an expression for the angle by which to rotate the input video
7436 clockwise, expressed as a number of radians. A negative value will
7437 result in a counter-clockwise rotation. By default it is set to "0".
7439 This expression is evaluated for each frame.
7442 Set the output width expression, default value is "iw".
7443 This expression is evaluated just once during configuration.
7446 Set the output height expression, default value is "ih".
7447 This expression is evaluated just once during configuration.
7450 Enable bilinear interpolation if set to 1, a value of 0 disables
7451 it. Default value is 1.
7454 Set the color used to fill the output area not covered by the rotated
7455 image. For the general syntax of this option, check the "Color" section in the
7456 ffmpeg-utils manual. If the special value "none" is selected then no
7457 background is printed (useful for example if the background is never shown).
7459 Default value is "black".
7462 The expressions for the angle and the output size can contain the
7463 following constants and functions:
7467 sequential number of the input frame, starting from 0. It is always NAN
7468 before the first frame is filtered.
7471 time in seconds of the input frame, it is set to 0 when the filter is
7472 configured. It is always NAN before the first frame is filtered.
7476 horizontal and vertical chroma subsample values. For example for the
7477 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7481 the input video width and height
7485 the output width and height, that is the size of the padded area as
7486 specified by the @var{width} and @var{height} expressions
7490 the minimal width/height required for completely containing the input
7491 video rotated by @var{a} radians.
7493 These are only available when computing the @option{out_w} and
7494 @option{out_h} expressions.
7497 @subsection Examples
7501 Rotate the input by PI/6 radians clockwise:
7507 Rotate the input by PI/6 radians counter-clockwise:
7513 Rotate the input by 45 degrees clockwise:
7519 Apply a constant rotation with period T, starting from an angle of PI/3:
7521 rotate=PI/3+2*PI*t/T
7525 Make the input video rotation oscillating with a period of T
7526 seconds and an amplitude of A radians:
7528 rotate=A*sin(2*PI/T*t)
7532 Rotate the video, output size is chosen so that the whole rotating
7533 input video is always completely contained in the output:
7535 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
7539 Rotate the video, reduce the output size so that no background is ever
7542 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
7546 @subsection Commands
7548 The filter supports the following commands:
7552 Set the angle expression.
7553 The command accepts the same syntax of the corresponding option.
7555 If the specified expression is not valid, it is kept at its current
7561 Apply Shape Adaptive Blur.
7563 The filter accepts the following options:
7566 @item luma_radius, lr
7567 Set luma blur filter strength, must be a value in range 0.1-4.0, default
7568 value is 1.0. A greater value will result in a more blurred image, and
7569 in slower processing.
7571 @item luma_pre_filter_radius, lpfr
7572 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
7575 @item luma_strength, ls
7576 Set luma maximum difference between pixels to still be considered, must
7577 be a value in the 0.1-100.0 range, default value is 1.0.
7579 @item chroma_radius, cr
7580 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
7581 greater value will result in a more blurred image, and in slower
7584 @item chroma_pre_filter_radius, cpfr
7585 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
7587 @item chroma_strength, cs
7588 Set chroma maximum difference between pixels to still be considered,
7589 must be a value in the 0.1-100.0 range.
7592 Each chroma option value, if not explicitly specified, is set to the
7593 corresponding luma option value.
7598 Scale (resize) the input video, using the libswscale library.
7600 The scale filter forces the output display aspect ratio to be the same
7601 of the input, by changing the output sample aspect ratio.
7603 If the input image format is different from the format requested by
7604 the next filter, the scale filter will convert the input to the
7608 The filter accepts the following options, or any of the options
7609 supported by the libswscale scaler.
7611 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
7612 the complete list of scaler options.
7617 Set the output video dimension expression. Default value is the input
7620 If the value is 0, the input width is used for the output.
7622 If one of the values is -1, the scale filter will use a value that
7623 maintains the aspect ratio of the input image, calculated from the
7624 other specified dimension. If both of them are -1, the input size is
7627 If one of the values is -n with n > 1, the scale filter will also use a value
7628 that maintains the aspect ratio of the input image, calculated from the other
7629 specified dimension. After that it will, however, make sure that the calculated
7630 dimension is divisible by n and adjust the value if necessary.
7632 See below for the list of accepted constants for use in the dimension
7636 Set the interlacing mode. It accepts the following values:
7640 Force interlaced aware scaling.
7643 Do not apply interlaced scaling.
7646 Select interlaced aware scaling depending on whether the source frames
7647 are flagged as interlaced or not.
7650 Default value is @samp{0}.
7653 Set libswscale scaling flags. See
7654 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7655 complete list of values. If not explicitly specified the filter applies
7659 Set the video size. For the syntax of this option, check the "Video size"
7660 section in the ffmpeg-utils manual.
7662 @item in_color_matrix
7663 @item out_color_matrix
7664 Set in/output YCbCr color space type.
7666 This allows the autodetected value to be overridden as well as allows forcing
7667 a specific value used for the output and encoder.
7669 If not specified, the color space type depends on the pixel format.
7675 Choose automatically.
7678 Format conforming to International Telecommunication Union (ITU)
7679 Recommendation BT.709.
7682 Set color space conforming to the United States Federal Communications
7683 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7686 Set color space conforming to:
7690 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7693 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7696 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7701 Set color space conforming to SMPTE ST 240:1999.
7706 Set in/output YCbCr sample range.
7708 This allows the autodetected value to be overridden as well as allows forcing
7709 a specific value used for the output and encoder. If not specified, the
7710 range depends on the pixel format. Possible values:
7714 Choose automatically.
7717 Set full range (0-255 in case of 8-bit luma).
7720 Set "MPEG" range (16-235 in case of 8-bit luma).
7723 @item force_original_aspect_ratio
7724 Enable decreasing or increasing output video width or height if necessary to
7725 keep the original aspect ratio. Possible values:
7729 Scale the video as specified and disable this feature.
7732 The output video dimensions will automatically be decreased if needed.
7735 The output video dimensions will automatically be increased if needed.
7739 One useful instance of this option is that when you know a specific device's
7740 maximum allowed resolution, you can use this to limit the output video to
7741 that, while retaining the aspect ratio. For example, device A allows
7742 1280x720 playback, and your video is 1920x800. Using this option (set it to
7743 decrease) and specifying 1280x720 to the command line makes the output
7746 Please note that this is a different thing than specifying -1 for @option{w}
7747 or @option{h}, you still need to specify the output resolution for this option
7752 The values of the @option{w} and @option{h} options are expressions
7753 containing the following constants:
7758 The input width and height
7762 These are the same as @var{in_w} and @var{in_h}.
7766 The output (scaled) width and height
7770 These are the same as @var{out_w} and @var{out_h}
7773 The same as @var{iw} / @var{ih}
7776 input sample aspect ratio
7779 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7783 horizontal and vertical input chroma subsample values. For example for the
7784 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7788 horizontal and vertical output chroma subsample values. For example for the
7789 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7792 @subsection Examples
7796 Scale the input video to a size of 200x100
7801 This is equivalent to:
7812 Specify a size abbreviation for the output size:
7817 which can also be written as:
7823 Scale the input to 2x:
7829 The above is the same as:
7835 Scale the input to 2x with forced interlaced scaling:
7837 scale=2*iw:2*ih:interl=1
7841 Scale the input to half size:
7847 Increase the width, and set the height to the same size:
7860 Increase the height, and set the width to 3/2 of the height:
7862 scale=w=3/2*oh:h=3/5*ih
7866 Increase the size, making the size a multiple of the chroma
7869 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7873 Increase the width to a maximum of 500 pixels,
7874 keeping the same aspect ratio as the input:
7876 scale=w='min(500\, iw*3/2):h=-1'
7880 @section separatefields
7882 The @code{separatefields} takes a frame-based video input and splits
7883 each frame into its components fields, producing a new half height clip
7884 with twice the frame rate and twice the frame count.
7886 This filter use field-dominance information in frame to decide which
7887 of each pair of fields to place first in the output.
7888 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7890 @section setdar, setsar
7892 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7895 This is done by changing the specified Sample (aka Pixel) Aspect
7896 Ratio, according to the following equation:
7898 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7901 Keep in mind that the @code{setdar} filter does not modify the pixel
7902 dimensions of the video frame. Also, the display aspect ratio set by
7903 this filter may be changed by later filters in the filterchain,
7904 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7907 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7908 the filter output video.
7910 Note that as a consequence of the application of this filter, the
7911 output display aspect ratio will change according to the equation
7914 Keep in mind that the sample aspect ratio set by the @code{setsar}
7915 filter may be changed by later filters in the filterchain, e.g. if
7916 another "setsar" or a "setdar" filter is applied.
7918 It accepts the following parameters:
7921 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7922 Set the aspect ratio used by the filter.
7924 The parameter can be a floating point number string, an expression, or
7925 a string of the form @var{num}:@var{den}, where @var{num} and
7926 @var{den} are the numerator and denominator of the aspect ratio. If
7927 the parameter is not specified, it is assumed the value "0".
7928 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7932 Set the maximum integer value to use for expressing numerator and
7933 denominator when reducing the expressed aspect ratio to a rational.
7934 Default value is @code{100}.
7938 The parameter @var{sar} is an expression containing
7939 the following constants:
7943 These are approximated values for the mathematical constants e
7944 (Euler's number), pi (Greek pi), and phi (the golden ratio).
7947 The input width and height.
7950 These are the same as @var{w} / @var{h}.
7953 The input sample aspect ratio.
7956 The input display aspect ratio. It is the same as
7957 (@var{w} / @var{h}) * @var{sar}.
7960 Horizontal and vertical chroma subsample values. For example, for the
7961 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7964 @subsection Examples
7969 To change the display aspect ratio to 16:9, specify one of the following:
7977 To change the sample aspect ratio to 10:11, specify:
7983 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7984 1000 in the aspect ratio reduction, use the command:
7986 setdar=ratio=16/9:max=1000
7994 Force field for the output video frame.
7996 The @code{setfield} filter marks the interlace type field for the
7997 output frames. It does not change the input frame, but only sets the
7998 corresponding property, which affects how the frame is treated by
7999 following filters (e.g. @code{fieldorder} or @code{yadif}).
8001 The filter accepts the following options:
8006 Available values are:
8010 Keep the same field property.
8013 Mark the frame as bottom-field-first.
8016 Mark the frame as top-field-first.
8019 Mark the frame as progressive.
8025 Show a line containing various information for each input video frame.
8026 The input video is not modified.
8028 The shown line contains a sequence of key/value pairs of the form
8029 @var{key}:@var{value}.
8031 The following values are shown in the output:
8035 The (sequential) number of the input frame, starting from 0.
8038 The Presentation TimeStamp of the input frame, expressed as a number of
8039 time base units. The time base unit depends on the filter input pad.
8042 The Presentation TimeStamp of the input frame, expressed as a number of
8046 The position of the frame in the input stream, or -1 if this information is
8047 unavailable and/or meaningless (for example in case of synthetic video).
8050 The pixel format name.
8053 The sample aspect ratio of the input frame, expressed in the form
8054 @var{num}/@var{den}.
8057 The size of the input frame. For the syntax of this option, check the "Video size"
8058 section in the ffmpeg-utils manual.
8061 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
8062 for bottom field first).
8065 This is 1 if the frame is a key frame, 0 otherwise.
8068 The picture type of the input frame ("I" for an I-frame, "P" for a
8069 P-frame, "B" for a B-frame, or "?" for an unknown type).
8070 Also refer to the documentation of the @code{AVPictureType} enum and of
8071 the @code{av_get_picture_type_char} function defined in
8072 @file{libavutil/avutil.h}.
8075 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
8077 @item plane_checksum
8078 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
8079 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
8082 @section showpalette
8084 Displays the 256 colors palette of each frame. This filter is only relevant for
8085 @var{pal8} pixel format frames.
8087 It accepts the following option:
8091 Set the size of the box used to represent one palette color entry. Default is
8092 @code{30} (for a @code{30x30} pixel box).
8095 @section shuffleplanes
8097 Reorder and/or duplicate video planes.
8099 It accepts the following parameters:
8104 The index of the input plane to be used as the first output plane.
8107 The index of the input plane to be used as the second output plane.
8110 The index of the input plane to be used as the third output plane.
8113 The index of the input plane to be used as the fourth output plane.
8117 The first plane has the index 0. The default is to keep the input unchanged.
8119 Swap the second and third planes of the input:
8121 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
8124 @section signalstats
8125 Evaluate various visual metrics that assist in determining issues associated
8126 with the digitization of analog video media.
8128 By default the filter will log these metadata values:
8132 Display the minimal Y value contained within the input frame. Expressed in
8136 Display the Y value at the 10% percentile within the input frame. Expressed in
8140 Display the average Y value within the input frame. Expressed in range of
8144 Display the Y value at the 90% percentile within the input frame. Expressed in
8148 Display the maximum Y value contained within the input frame. Expressed in
8152 Display the minimal U value contained within the input frame. Expressed in
8156 Display the U value at the 10% percentile within the input frame. Expressed in
8160 Display the average U value within the input frame. Expressed in range of
8164 Display the U value at the 90% percentile within the input frame. Expressed in
8168 Display the maximum U value contained within the input frame. Expressed in
8172 Display the minimal V value contained within the input frame. Expressed in
8176 Display the V value at the 10% percentile within the input frame. Expressed in
8180 Display the average V value within the input frame. Expressed in range of
8184 Display the V value at the 90% percentile within the input frame. Expressed in
8188 Display the maximum V value contained within the input frame. Expressed in
8192 Display the minimal saturation value contained within the input frame.
8193 Expressed in range of [0-~181.02].
8196 Display the saturation value at the 10% percentile within the input frame.
8197 Expressed in range of [0-~181.02].
8200 Display the average saturation value within the input frame. Expressed in range
8204 Display the saturation value at the 90% percentile within the input frame.
8205 Expressed in range of [0-~181.02].
8208 Display the maximum saturation value contained within the input frame.
8209 Expressed in range of [0-~181.02].
8212 Display the median value for hue within the input frame. Expressed in range of
8216 Display the average value for hue within the input frame. Expressed in range of
8220 Display the average of sample value difference between all values of the Y
8221 plane in the current frame and corresponding values of the previous input frame.
8222 Expressed in range of [0-255].
8225 Display the average of sample value difference between all values of the U
8226 plane in the current frame and corresponding values of the previous input frame.
8227 Expressed in range of [0-255].
8230 Display the average of sample value difference between all values of the V
8231 plane in the current frame and corresponding values of the previous input frame.
8232 Expressed in range of [0-255].
8235 The filter accepts the following options:
8241 @option{stat} specify an additional form of image analysis.
8242 @option{out} output video with the specified type of pixel highlighted.
8244 Both options accept the following values:
8248 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
8249 unlike the neighboring pixels of the same field. Examples of temporal outliers
8250 include the results of video dropouts, head clogs, or tape tracking issues.
8253 Identify @var{vertical line repetition}. Vertical line repetition includes
8254 similar rows of pixels within a frame. In born-digital video vertical line
8255 repetition is common, but this pattern is uncommon in video digitized from an
8256 analog source. When it occurs in video that results from the digitization of an
8257 analog source it can indicate concealment from a dropout compensator.
8260 Identify pixels that fall outside of legal broadcast range.
8264 Set the highlight color for the @option{out} option. The default color is
8268 @subsection Examples
8272 Output data of various video metrics:
8274 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
8278 Output specific data about the minimum and maximum values of the Y plane per frame:
8280 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
8284 Playback video while highlighting pixels that are outside of broadcast range in red.
8286 ffplay example.mov -vf signalstats="out=brng:color=red"
8290 Playback video with signalstats metadata drawn over the frame.
8292 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
8295 The contents of signalstat_drawtext.txt used in the command are:
8298 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
8299 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
8300 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
8301 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
8309 Blur the input video without impacting the outlines.
8311 It accepts the following options:
8314 @item luma_radius, lr
8315 Set the luma radius. The option value must be a float number in
8316 the range [0.1,5.0] that specifies the variance of the gaussian filter
8317 used to blur the image (slower if larger). Default value is 1.0.
8319 @item luma_strength, ls
8320 Set the luma strength. The option value must be a float number
8321 in the range [-1.0,1.0] that configures the blurring. A value included
8322 in [0.0,1.0] will blur the image whereas a value included in
8323 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8325 @item luma_threshold, lt
8326 Set the luma threshold used as a coefficient to determine
8327 whether a pixel should be blurred or not. The option value must be an
8328 integer in the range [-30,30]. A value of 0 will filter all the image,
8329 a value included in [0,30] will filter flat areas and a value included
8330 in [-30,0] will filter edges. Default value is 0.
8332 @item chroma_radius, cr
8333 Set the chroma radius. The option value must be a float number in
8334 the range [0.1,5.0] that specifies the variance of the gaussian filter
8335 used to blur the image (slower if larger). Default value is 1.0.
8337 @item chroma_strength, cs
8338 Set the chroma strength. The option value must be a float number
8339 in the range [-1.0,1.0] that configures the blurring. A value included
8340 in [0.0,1.0] will blur the image whereas a value included in
8341 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8343 @item chroma_threshold, ct
8344 Set the chroma threshold used as a coefficient to determine
8345 whether a pixel should be blurred or not. The option value must be an
8346 integer in the range [-30,30]. A value of 0 will filter all the image,
8347 a value included in [0,30] will filter flat areas and a value included
8348 in [-30,0] will filter edges. Default value is 0.
8351 If a chroma option is not explicitly set, the corresponding luma value
8356 Convert between different stereoscopic image formats.
8358 The filters accept the following options:
8362 Set stereoscopic image format of input.
8364 Available values for input image formats are:
8367 side by side parallel (left eye left, right eye right)
8370 side by side crosseye (right eye left, left eye right)
8373 side by side parallel with half width resolution
8374 (left eye left, right eye right)
8377 side by side crosseye with half width resolution
8378 (right eye left, left eye right)
8381 above-below (left eye above, right eye below)
8384 above-below (right eye above, left eye below)
8387 above-below with half height resolution
8388 (left eye above, right eye below)
8391 above-below with half height resolution
8392 (right eye above, left eye below)
8395 alternating frames (left eye first, right eye second)
8398 alternating frames (right eye first, left eye second)
8400 Default value is @samp{sbsl}.
8404 Set stereoscopic image format of output.
8406 Available values for output image formats are all the input formats as well as:
8409 anaglyph red/blue gray
8410 (red filter on left eye, blue filter on right eye)
8413 anaglyph red/green gray
8414 (red filter on left eye, green filter on right eye)
8417 anaglyph red/cyan gray
8418 (red filter on left eye, cyan filter on right eye)
8421 anaglyph red/cyan half colored
8422 (red filter on left eye, cyan filter on right eye)
8425 anaglyph red/cyan color
8426 (red filter on left eye, cyan filter on right eye)
8429 anaglyph red/cyan color optimized with the least squares projection of dubois
8430 (red filter on left eye, cyan filter on right eye)
8433 anaglyph green/magenta gray
8434 (green filter on left eye, magenta filter on right eye)
8437 anaglyph green/magenta half colored
8438 (green filter on left eye, magenta filter on right eye)
8441 anaglyph green/magenta colored
8442 (green filter on left eye, magenta filter on right eye)
8445 anaglyph green/magenta color optimized with the least squares projection of dubois
8446 (green filter on left eye, magenta filter on right eye)
8449 anaglyph yellow/blue gray
8450 (yellow filter on left eye, blue filter on right eye)
8453 anaglyph yellow/blue half colored
8454 (yellow filter on left eye, blue filter on right eye)
8457 anaglyph yellow/blue colored
8458 (yellow filter on left eye, blue filter on right eye)
8461 anaglyph yellow/blue color optimized with the least squares projection of dubois
8462 (yellow filter on left eye, blue filter on right eye)
8465 interleaved rows (left eye has top row, right eye starts on next row)
8468 interleaved rows (right eye has top row, left eye starts on next row)
8471 mono output (left eye only)
8474 mono output (right eye only)
8477 Default value is @samp{arcd}.
8480 @subsection Examples
8484 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
8490 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
8499 Apply a simple postprocessing filter that compresses and decompresses the image
8500 at several (or - in the case of @option{quality} level @code{6} - all) shifts
8501 and average the results.
8503 The filter accepts the following options:
8507 Set quality. This option defines the number of levels for averaging. It accepts
8508 an integer in the range 0-6. If set to @code{0}, the filter will have no
8509 effect. A value of @code{6} means the higher quality. For each increment of
8510 that value the speed drops by a factor of approximately 2. Default value is
8514 Force a constant quantization parameter. If not set, the filter will use the QP
8515 from the video stream (if available).
8518 Set thresholding mode. Available modes are:
8522 Set hard thresholding (default).
8524 Set soft thresholding (better de-ringing effect, but likely blurrier).
8528 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8529 option may cause flicker since the B-Frames have often larger QP. Default is
8530 @code{0} (not enabled).
8536 Draw subtitles on top of input video using the libass library.
8538 To enable compilation of this filter you need to configure FFmpeg with
8539 @code{--enable-libass}. This filter also requires a build with libavcodec and
8540 libavformat to convert the passed subtitles file to ASS (Advanced Substation
8541 Alpha) subtitles format.
8543 The filter accepts the following options:
8547 Set the filename of the subtitle file to read. It must be specified.
8550 Specify the size of the original video, the video for which the ASS file
8551 was composed. For the syntax of this option, check the "Video size" section in
8552 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
8553 this is necessary to correctly scale the fonts if the aspect ratio has been
8557 Set subtitles input character encoding. @code{subtitles} filter only. Only
8558 useful if not UTF-8.
8560 @item stream_index, si
8561 Set subtitles stream index. @code{subtitles} filter only.
8564 Override default style or script info parameters of the subtitles. It accepts a
8565 string containing ASS style format @code{KEY=VALUE} couples separated by ",".
8568 If the first key is not specified, it is assumed that the first value
8569 specifies the @option{filename}.
8571 For example, to render the file @file{sub.srt} on top of the input
8572 video, use the command:
8577 which is equivalent to:
8579 subtitles=filename=sub.srt
8582 To render the default subtitles stream from file @file{video.mkv}, use:
8587 To render the second subtitles stream from that file, use:
8589 subtitles=video.mkv:si=1
8592 To make the subtitles stream from @file{sub.srt} appear in transparent green
8593 @code{DejaVu Serif}, use:
8595 subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'
8600 Scale the input by 2x and smooth using the Super2xSaI (Scale and
8601 Interpolate) pixel art scaling algorithm.
8603 Useful for enlarging pixel art images without reducing sharpness.
8610 Apply telecine process to the video.
8612 This filter accepts the following options:
8621 The default value is @code{top}.
8625 A string of numbers representing the pulldown pattern you wish to apply.
8626 The default value is @code{23}.
8630 Some typical patterns:
8635 24p: 2332 (preferred)
8642 24p: 222222222223 ("Euro pulldown")
8648 Select the most representative frame in a given sequence of consecutive frames.
8650 The filter accepts the following options:
8654 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
8655 will pick one of them, and then handle the next batch of @var{n} frames until
8656 the end. Default is @code{100}.
8659 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
8660 value will result in a higher memory usage, so a high value is not recommended.
8662 @subsection Examples
8666 Extract one picture each 50 frames:
8672 Complete example of a thumbnail creation with @command{ffmpeg}:
8674 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
8680 Tile several successive frames together.
8682 The filter accepts the following options:
8687 Set the grid size (i.e. the number of lines and columns). For the syntax of
8688 this option, check the "Video size" section in the ffmpeg-utils manual.
8691 Set the maximum number of frames to render in the given area. It must be less
8692 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
8693 the area will be used.
8696 Set the outer border margin in pixels.
8699 Set the inner border thickness (i.e. the number of pixels between frames). For
8700 more advanced padding options (such as having different values for the edges),
8701 refer to the pad video filter.
8704 Specify the color of the unused area. For the syntax of this option, check the
8705 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
8709 @subsection Examples
8713 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
8715 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
8717 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
8718 duplicating each output frame to accommodate the originally detected frame
8722 Display @code{5} pictures in an area of @code{3x2} frames,
8723 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
8724 mixed flat and named options:
8726 tile=3x2:nb_frames=5:padding=7:margin=2
8732 Perform various types of temporal field interlacing.
8734 Frames are counted starting from 1, so the first input frame is
8737 The filter accepts the following options:
8742 Specify the mode of the interlacing. This option can also be specified
8743 as a value alone. See below for a list of values for this option.
8745 Available values are:
8749 Move odd frames into the upper field, even into the lower field,
8750 generating a double height frame at half frame rate.
8754 Frame 1 Frame 2 Frame 3 Frame 4
8756 11111 22222 33333 44444
8757 11111 22222 33333 44444
8758 11111 22222 33333 44444
8759 11111 22222 33333 44444
8773 Only output even frames, odd frames are dropped, generating a frame with
8774 unchanged height at half frame rate.
8779 Frame 1 Frame 2 Frame 3 Frame 4
8781 11111 22222 33333 44444
8782 11111 22222 33333 44444
8783 11111 22222 33333 44444
8784 11111 22222 33333 44444
8794 Only output odd frames, even frames are dropped, generating a frame with
8795 unchanged height at half frame rate.
8800 Frame 1 Frame 2 Frame 3 Frame 4
8802 11111 22222 33333 44444
8803 11111 22222 33333 44444
8804 11111 22222 33333 44444
8805 11111 22222 33333 44444
8815 Expand each frame to full height, but pad alternate lines with black,
8816 generating a frame with double height at the same input frame rate.
8821 Frame 1 Frame 2 Frame 3 Frame 4
8823 11111 22222 33333 44444
8824 11111 22222 33333 44444
8825 11111 22222 33333 44444
8826 11111 22222 33333 44444
8829 11111 ..... 33333 .....
8830 ..... 22222 ..... 44444
8831 11111 ..... 33333 .....
8832 ..... 22222 ..... 44444
8833 11111 ..... 33333 .....
8834 ..... 22222 ..... 44444
8835 11111 ..... 33333 .....
8836 ..... 22222 ..... 44444
8840 @item interleave_top, 4
8841 Interleave the upper field from odd frames with the lower field from
8842 even frames, generating a frame with unchanged height at half frame rate.
8847 Frame 1 Frame 2 Frame 3 Frame 4
8849 11111<- 22222 33333<- 44444
8850 11111 22222<- 33333 44444<-
8851 11111<- 22222 33333<- 44444
8852 11111 22222<- 33333 44444<-
8862 @item interleave_bottom, 5
8863 Interleave the lower field from odd frames with the upper field from
8864 even frames, generating a frame with unchanged height at half frame rate.
8869 Frame 1 Frame 2 Frame 3 Frame 4
8871 11111 22222<- 33333 44444<-
8872 11111<- 22222 33333<- 44444
8873 11111 22222<- 33333 44444<-
8874 11111<- 22222 33333<- 44444
8884 @item interlacex2, 6
8885 Double frame rate with unchanged height. Frames are inserted each
8886 containing the second temporal field from the previous input frame and
8887 the first temporal field from the next input frame. This mode relies on
8888 the top_field_first flag. Useful for interlaced video displays with no
8889 field synchronisation.
8894 Frame 1 Frame 2 Frame 3 Frame 4
8896 11111 22222 33333 44444
8897 11111 22222 33333 44444
8898 11111 22222 33333 44444
8899 11111 22222 33333 44444
8902 11111 22222 22222 33333 33333 44444 44444
8903 11111 11111 22222 22222 33333 33333 44444
8904 11111 22222 22222 33333 33333 44444 44444
8905 11111 11111 22222 22222 33333 33333 44444
8911 Numeric values are deprecated but are accepted for backward
8912 compatibility reasons.
8914 Default mode is @code{merge}.
8917 Specify flags influencing the filter process.
8919 Available value for @var{flags} is:
8922 @item low_pass_filter, vlfp
8923 Enable vertical low-pass filtering in the filter.
8924 Vertical low-pass filtering is required when creating an interlaced
8925 destination from a progressive source which contains high-frequency
8926 vertical detail. Filtering will reduce interlace 'twitter' and Moire
8929 Vertical low-pass filtering can only be enabled for @option{mode}
8930 @var{interleave_top} and @var{interleave_bottom}.
8937 Transpose rows with columns in the input video and optionally flip it.
8939 It accepts the following parameters:
8944 Specify the transposition direction.
8946 Can assume the following values:
8948 @item 0, 4, cclock_flip
8949 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
8957 Rotate by 90 degrees clockwise, that is:
8965 Rotate by 90 degrees counterclockwise, that is:
8972 @item 3, 7, clock_flip
8973 Rotate by 90 degrees clockwise and vertically flip, that is:
8981 For values between 4-7, the transposition is only done if the input
8982 video geometry is portrait and not landscape. These values are
8983 deprecated, the @code{passthrough} option should be used instead.
8985 Numerical values are deprecated, and should be dropped in favor of
8989 Do not apply the transposition if the input geometry matches the one
8990 specified by the specified value. It accepts the following values:
8993 Always apply transposition.
8995 Preserve portrait geometry (when @var{height} >= @var{width}).
8997 Preserve landscape geometry (when @var{width} >= @var{height}).
9000 Default value is @code{none}.
9003 For example to rotate by 90 degrees clockwise and preserve portrait
9006 transpose=dir=1:passthrough=portrait
9009 The command above can also be specified as:
9011 transpose=1:portrait
9015 Trim the input so that the output contains one continuous subpart of the input.
9017 It accepts the following parameters:
9020 Specify the time of the start of the kept section, i.e. the frame with the
9021 timestamp @var{start} will be the first frame in the output.
9024 Specify the time of the first frame that will be dropped, i.e. the frame
9025 immediately preceding the one with the timestamp @var{end} will be the last
9026 frame in the output.
9029 This is the same as @var{start}, except this option sets the start timestamp
9030 in timebase units instead of seconds.
9033 This is the same as @var{end}, except this option sets the end timestamp
9034 in timebase units instead of seconds.
9037 The maximum duration of the output in seconds.
9040 The number of the first frame that should be passed to the output.
9043 The number of the first frame that should be dropped.
9046 @option{start}, @option{end}, and @option{duration} are expressed as time
9047 duration specifications; see
9048 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
9049 for the accepted syntax.
9051 Note that the first two sets of the start/end options and the @option{duration}
9052 option look at the frame timestamp, while the _frame variants simply count the
9053 frames that pass through the filter. Also note that this filter does not modify
9054 the timestamps. If you wish for the output timestamps to start at zero, insert a
9055 setpts filter after the trim filter.
9057 If multiple start or end options are set, this filter tries to be greedy and
9058 keep all the frames that match at least one of the specified constraints. To keep
9059 only the part that matches all the constraints at once, chain multiple trim
9062 The defaults are such that all the input is kept. So it is possible to set e.g.
9063 just the end values to keep everything before the specified time.
9068 Drop everything except the second minute of input:
9070 ffmpeg -i INPUT -vf trim=60:120
9074 Keep only the first second:
9076 ffmpeg -i INPUT -vf trim=duration=1
9085 Sharpen or blur the input video.
9087 It accepts the following parameters:
9090 @item luma_msize_x, lx
9091 Set the luma matrix horizontal size. It must be an odd integer between
9092 3 and 63. The default value is 5.
9094 @item luma_msize_y, ly
9095 Set the luma matrix vertical size. It must be an odd integer between 3
9096 and 63. The default value is 5.
9098 @item luma_amount, la
9099 Set the luma effect strength. It must be a floating point number, reasonable
9100 values lay between -1.5 and 1.5.
9102 Negative values will blur the input video, while positive values will
9103 sharpen it, a value of zero will disable the effect.
9105 Default value is 1.0.
9107 @item chroma_msize_x, cx
9108 Set the chroma matrix horizontal size. It must be an odd integer
9109 between 3 and 63. The default value is 5.
9111 @item chroma_msize_y, cy
9112 Set the chroma matrix vertical size. It must be an odd integer
9113 between 3 and 63. The default value is 5.
9115 @item chroma_amount, ca
9116 Set the chroma effect strength. It must be a floating point number, reasonable
9117 values lay between -1.5 and 1.5.
9119 Negative values will blur the input video, while positive values will
9120 sharpen it, a value of zero will disable the effect.
9122 Default value is 0.0.
9125 If set to 1, specify using OpenCL capabilities, only available if
9126 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
9130 All parameters are optional and default to the equivalent of the
9131 string '5:5:1.0:5:5:0.0'.
9133 @subsection Examples
9137 Apply strong luma sharpen effect:
9139 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
9143 Apply a strong blur of both luma and chroma parameters:
9145 unsharp=7:7:-2:7:7:-2
9151 Apply ultra slow/simple postprocessing filter that compresses and decompresses
9152 the image at several (or - in the case of @option{quality} level @code{8} - all)
9153 shifts and average the results.
9155 The way this differs from the behavior of spp is that uspp actually encodes &
9156 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
9157 DCT similar to MJPEG.
9159 The filter accepts the following options:
9163 Set quality. This option defines the number of levels for averaging. It accepts
9164 an integer in the range 0-8. If set to @code{0}, the filter will have no
9165 effect. A value of @code{8} means the higher quality. For each increment of
9166 that value the speed drops by a factor of approximately 2. Default value is
9170 Force a constant quantization parameter. If not set, the filter will use the QP
9171 from the video stream (if available).
9174 @anchor{vidstabdetect}
9175 @section vidstabdetect
9177 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
9178 @ref{vidstabtransform} for pass 2.
9180 This filter generates a file with relative translation and rotation
9181 transform information about subsequent frames, which is then used by
9182 the @ref{vidstabtransform} filter.
9184 To enable compilation of this filter you need to configure FFmpeg with
9185 @code{--enable-libvidstab}.
9187 This filter accepts the following options:
9191 Set the path to the file used to write the transforms information.
9192 Default value is @file{transforms.trf}.
9195 Set how shaky the video is and how quick the camera is. It accepts an
9196 integer in the range 1-10, a value of 1 means little shakiness, a
9197 value of 10 means strong shakiness. Default value is 5.
9200 Set the accuracy of the detection process. It must be a value in the
9201 range 1-15. A value of 1 means low accuracy, a value of 15 means high
9202 accuracy. Default value is 15.
9205 Set stepsize of the search process. The region around minimum is
9206 scanned with 1 pixel resolution. Default value is 6.
9209 Set minimum contrast. Below this value a local measurement field is
9210 discarded. Must be a floating point value in the range 0-1. Default
9214 Set reference frame number for tripod mode.
9216 If enabled, the motion of the frames is compared to a reference frame
9217 in the filtered stream, identified by the specified number. The idea
9218 is to compensate all movements in a more-or-less static scene and keep
9219 the camera view absolutely still.
9221 If set to 0, it is disabled. The frames are counted starting from 1.
9224 Show fields and transforms in the resulting frames. It accepts an
9225 integer in the range 0-2. Default value is 0, which disables any
9229 @subsection Examples
9239 Analyze strongly shaky movie and put the results in file
9240 @file{mytransforms.trf}:
9242 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
9246 Visualize the result of internal transformations in the resulting
9249 vidstabdetect=show=1
9253 Analyze a video with medium shakiness using @command{ffmpeg}:
9255 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
9259 @anchor{vidstabtransform}
9260 @section vidstabtransform
9262 Video stabilization/deshaking: pass 2 of 2,
9263 see @ref{vidstabdetect} for pass 1.
9265 Read a file with transform information for each frame and
9266 apply/compensate them. Together with the @ref{vidstabdetect}
9267 filter this can be used to deshake videos. See also
9268 @url{http://public.hronopik.de/vid.stab}. It is important to also use
9269 the @ref{unsharp} filter, see below.
9271 To enable compilation of this filter you need to configure FFmpeg with
9272 @code{--enable-libvidstab}.
9278 Set path to the file used to read the transforms. Default value is
9279 @file{transforms.trf}.
9282 Set the number of frames (value*2 + 1) used for lowpass filtering the
9283 camera movements. Default value is 10.
9285 For example a number of 10 means that 21 frames are used (10 in the
9286 past and 10 in the future) to smoothen the motion in the video. A
9287 larger value leads to a smoother video, but limits the acceleration of
9288 the camera (pan/tilt movements). 0 is a special case where a static
9289 camera is simulated.
9292 Set the camera path optimization algorithm.
9294 Accepted values are:
9297 gaussian kernel low-pass filter on camera motion (default)
9299 averaging on transformations
9303 Set maximal number of pixels to translate frames. Default value is -1,
9307 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
9308 value is -1, meaning no limit.
9311 Specify how to deal with borders that may be visible due to movement
9314 Available values are:
9317 keep image information from previous frame (default)
9319 fill the border black
9323 Invert transforms if set to 1. Default value is 0.
9326 Consider transforms as relative to previous frame if set to 1,
9327 absolute if set to 0. Default value is 0.
9330 Set percentage to zoom. A positive value will result in a zoom-in
9331 effect, a negative value in a zoom-out effect. Default value is 0 (no
9335 Set optimal zooming to avoid borders.
9337 Accepted values are:
9342 optimal static zoom value is determined (only very strong movements
9343 will lead to visible borders) (default)
9345 optimal adaptive zoom value is determined (no borders will be
9346 visible), see @option{zoomspeed}
9349 Note that the value given at zoom is added to the one calculated here.
9352 Set percent to zoom maximally each frame (enabled when
9353 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
9357 Specify type of interpolation.
9359 Available values are:
9364 linear only horizontal
9366 linear in both directions (default)
9368 cubic in both directions (slow)
9372 Enable virtual tripod mode if set to 1, which is equivalent to
9373 @code{relative=0:smoothing=0}. Default value is 0.
9375 Use also @code{tripod} option of @ref{vidstabdetect}.
9378 Increase log verbosity if set to 1. Also the detected global motions
9379 are written to the temporary file @file{global_motions.trf}. Default
9383 @subsection Examples
9387 Use @command{ffmpeg} for a typical stabilization with default values:
9389 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
9392 Note the use of the @ref{unsharp} filter which is always recommended.
9395 Zoom in a bit more and load transform data from a given file:
9397 vidstabtransform=zoom=5:input="mytransforms.trf"
9401 Smoothen the video even more:
9403 vidstabtransform=smoothing=30
9409 Flip the input video vertically.
9411 For example, to vertically flip a video with @command{ffmpeg}:
9413 ffmpeg -i in.avi -vf "vflip" out.avi
9419 Make or reverse a natural vignetting effect.
9421 The filter accepts the following options:
9425 Set lens angle expression as a number of radians.
9427 The value is clipped in the @code{[0,PI/2]} range.
9429 Default value: @code{"PI/5"}
9433 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
9437 Set forward/backward mode.
9439 Available modes are:
9442 The larger the distance from the central point, the darker the image becomes.
9445 The larger the distance from the central point, the brighter the image becomes.
9446 This can be used to reverse a vignette effect, though there is no automatic
9447 detection to extract the lens @option{angle} and other settings (yet). It can
9448 also be used to create a burning effect.
9451 Default value is @samp{forward}.
9454 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
9456 It accepts the following values:
9459 Evaluate expressions only once during the filter initialization.
9462 Evaluate expressions for each incoming frame. This is way slower than the
9463 @samp{init} mode since it requires all the scalers to be re-computed, but it
9464 allows advanced dynamic expressions.
9467 Default value is @samp{init}.
9470 Set dithering to reduce the circular banding effects. Default is @code{1}
9474 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
9475 Setting this value to the SAR of the input will make a rectangular vignetting
9476 following the dimensions of the video.
9478 Default is @code{1/1}.
9481 @subsection Expressions
9483 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
9484 following parameters.
9489 input width and height
9492 the number of input frame, starting from 0
9495 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
9496 @var{TB} units, NAN if undefined
9499 frame rate of the input video, NAN if the input frame rate is unknown
9502 the PTS (Presentation TimeStamp) of the filtered video frame,
9503 expressed in seconds, NAN if undefined
9506 time base of the input video
9510 @subsection Examples
9514 Apply simple strong vignetting effect:
9520 Make a flickering vignetting:
9522 vignette='PI/4+random(1)*PI/50':eval=frame
9529 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
9530 Deinterlacing Filter").
9532 Based on the process described by Martin Weston for BBC R&D, and
9533 implemented based on the de-interlace algorithm written by Jim
9534 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
9535 uses filter coefficients calculated by BBC R&D.
9537 There are two sets of filter coefficients, so called "simple":
9538 and "complex". Which set of filter coefficients is used can
9539 be set by passing an optional parameter:
9543 Set the interlacing filter coefficients. Accepts one of the following values:
9547 Simple filter coefficient set.
9549 More-complex filter coefficient set.
9551 Default value is @samp{complex}.
9554 Specify which frames to deinterlace. Accept one of the following values:
9558 Deinterlace all frames,
9560 Only deinterlace frames marked as interlaced.
9563 Default value is @samp{all}.
9567 Apply the xBR high-quality magnification filter which is designed for pixel
9568 art. It follows a set of edge-detection rules, see
9569 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
9571 It accepts the following option:
9575 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
9576 @code{3xBR} and @code{4} for @code{4xBR}.
9577 Default is @code{3}.
9583 Deinterlace the input video ("yadif" means "yet another deinterlacing
9586 It accepts the following parameters:
9592 The interlacing mode to adopt. It accepts one of the following values:
9596 Output one frame for each frame.
9598 Output one frame for each field.
9599 @item 2, send_frame_nospatial
9600 Like @code{send_frame}, but it skips the spatial interlacing check.
9601 @item 3, send_field_nospatial
9602 Like @code{send_field}, but it skips the spatial interlacing check.
9605 The default value is @code{send_frame}.
9608 The picture field parity assumed for the input interlaced video. It accepts one
9609 of the following values:
9613 Assume the top field is first.
9615 Assume the bottom field is first.
9617 Enable automatic detection of field parity.
9620 The default value is @code{auto}.
9621 If the interlacing is unknown or the decoder does not export this information,
9622 top field first will be assumed.
9625 Specify which frames to deinterlace. Accept one of the following
9630 Deinterlace all frames.
9632 Only deinterlace frames marked as interlaced.
9635 The default value is @code{all}.
9640 Apply Zoom & Pan effect.
9642 This filter accepts the following options:
9646 Set the zoom expression. Default is 1.
9650 Set the x and y expression. Default is 0.
9653 Set the duration expression in number of frames.
9654 This sets for how many number of frames effect will last for
9658 Set the output image size, default is 'hd720'.
9661 Each expression can contain the following constants:
9684 Last calculated 'x' and 'y' position from 'x' and 'y' expression
9685 for current input frame.
9689 'x' and 'y' of last output frame of previous input frame or 0 when there was
9690 not yet such frame (first input frame).
9693 Last calculated zoom from 'z' expression for current input frame.
9696 Last calculated zoom of last output frame of previous input frame.
9699 Number of output frames for current input frame. Calculated from 'd' expression
9700 for each input frame.
9703 number of output frames created for previous input frame
9706 Rational number: input width / input height
9712 display aspect ratio
9716 @subsection Examples
9720 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
9722 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
9726 @c man end VIDEO FILTERS
9728 @chapter Video Sources
9729 @c man begin VIDEO SOURCES
9731 Below is a description of the currently available video sources.
9735 Buffer video frames, and make them available to the filter chain.
9737 This source is mainly intended for a programmatic use, in particular
9738 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
9740 It accepts the following parameters:
9745 Specify the size (width and height) of the buffered video frames. For the
9746 syntax of this option, check the "Video size" section in the ffmpeg-utils
9750 The input video width.
9753 The input video height.
9756 A string representing the pixel format of the buffered video frames.
9757 It may be a number corresponding to a pixel format, or a pixel format
9761 Specify the timebase assumed by the timestamps of the buffered frames.
9764 Specify the frame rate expected for the video stream.
9766 @item pixel_aspect, sar
9767 The sample (pixel) aspect ratio of the input video.
9770 Specify the optional parameters to be used for the scale filter which
9771 is automatically inserted when an input change is detected in the
9772 input size or format.
9777 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
9780 will instruct the source to accept video frames with size 320x240 and
9781 with format "yuv410p", assuming 1/24 as the timestamps timebase and
9782 square pixels (1:1 sample aspect ratio).
9783 Since the pixel format with name "yuv410p" corresponds to the number 6
9784 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
9785 this example corresponds to:
9787 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
9790 Alternatively, the options can be specified as a flat string, but this
9791 syntax is deprecated:
9793 @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}]
9797 Create a pattern generated by an elementary cellular automaton.
9799 The initial state of the cellular automaton can be defined through the
9800 @option{filename}, and @option{pattern} options. If such options are
9801 not specified an initial state is created randomly.
9803 At each new frame a new row in the video is filled with the result of
9804 the cellular automaton next generation. The behavior when the whole
9805 frame is filled is defined by the @option{scroll} option.
9807 This source accepts the following options:
9811 Read the initial cellular automaton state, i.e. the starting row, from
9813 In the file, each non-whitespace character is considered an alive
9814 cell, a newline will terminate the row, and further characters in the
9815 file will be ignored.
9818 Read the initial cellular automaton state, i.e. the starting row, from
9819 the specified string.
9821 Each non-whitespace character in the string is considered an alive
9822 cell, a newline will terminate the row, and further characters in the
9823 string will be ignored.
9826 Set the video rate, that is the number of frames generated per second.
9829 @item random_fill_ratio, ratio
9830 Set the random fill ratio for the initial cellular automaton row. It
9831 is a floating point number value ranging from 0 to 1, defaults to
9834 This option is ignored when a file or a pattern is specified.
9836 @item random_seed, seed
9837 Set the seed for filling randomly the initial row, must be an integer
9838 included between 0 and UINT32_MAX. If not specified, or if explicitly
9839 set to -1, the filter will try to use a good random seed on a best
9843 Set the cellular automaton rule, it is a number ranging from 0 to 255.
9844 Default value is 110.
9847 Set the size of the output video. For the syntax of this option, check
9848 the "Video size" section in the ffmpeg-utils manual.
9850 If @option{filename} or @option{pattern} is specified, the size is set
9851 by default to the width of the specified initial state row, and the
9852 height is set to @var{width} * PHI.
9854 If @option{size} is set, it must contain the width of the specified
9855 pattern string, and the specified pattern will be centered in the
9858 If a filename or a pattern string is not specified, the size value
9859 defaults to "320x518" (used for a randomly generated initial state).
9862 If set to 1, scroll the output upward when all the rows in the output
9863 have been already filled. If set to 0, the new generated row will be
9864 written over the top row just after the bottom row is filled.
9867 @item start_full, full
9868 If set to 1, completely fill the output with generated rows before
9869 outputting the first frame.
9870 This is the default behavior, for disabling set the value to 0.
9873 If set to 1, stitch the left and right row edges together.
9874 This is the default behavior, for disabling set the value to 0.
9877 @subsection Examples
9881 Read the initial state from @file{pattern}, and specify an output of
9884 cellauto=f=pattern:s=200x400
9888 Generate a random initial row with a width of 200 cells, with a fill
9891 cellauto=ratio=2/3:s=200x200
9895 Create a pattern generated by rule 18 starting by a single alive cell
9896 centered on an initial row with width 100:
9898 cellauto=p=@@:s=100x400:full=0:rule=18
9902 Specify a more elaborated initial pattern:
9904 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
9911 Generate a Mandelbrot set fractal, and progressively zoom towards the
9912 point specified with @var{start_x} and @var{start_y}.
9914 This source accepts the following options:
9919 Set the terminal pts value. Default value is 400.
9922 Set the terminal scale value.
9923 Must be a floating point value. Default value is 0.3.
9926 Set the inner coloring mode, that is the algorithm used to draw the
9927 Mandelbrot fractal internal region.
9929 It shall assume one of the following values:
9934 Show time until convergence.
9936 Set color based on point closest to the origin of the iterations.
9941 Default value is @var{mincol}.
9944 Set the bailout value. Default value is 10.0.
9947 Set the maximum of iterations performed by the rendering
9948 algorithm. Default value is 7189.
9951 Set outer coloring mode.
9952 It shall assume one of following values:
9954 @item iteration_count
9955 Set iteration cound mode.
9956 @item normalized_iteration_count
9957 set normalized iteration count mode.
9959 Default value is @var{normalized_iteration_count}.
9962 Set frame rate, expressed as number of frames per second. Default
9966 Set frame size. For the syntax of this option, check the "Video
9967 size" section in the ffmpeg-utils manual. Default value is "640x480".
9970 Set the initial scale value. Default value is 3.0.
9973 Set the initial x position. Must be a floating point value between
9974 -100 and 100. Default value is -0.743643887037158704752191506114774.
9977 Set the initial y position. Must be a floating point value between
9978 -100 and 100. Default value is -0.131825904205311970493132056385139.
9983 Generate various test patterns, as generated by the MPlayer test filter.
9985 The size of the generated video is fixed, and is 256x256.
9986 This source is useful in particular for testing encoding features.
9988 This source accepts the following options:
9993 Specify the frame rate of the sourced video, as the number of frames
9994 generated per second. It has to be a string in the format
9995 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9996 number or a valid video frame rate abbreviation. The default value is
10000 Set the duration of the sourced video. See
10001 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
10002 for the accepted syntax.
10004 If not specified, or the expressed duration is negative, the video is
10005 supposed to be generated forever.
10009 Set the number or the name of the test to perform. Supported tests are:
10025 Default value is "all", which will cycle through the list of all tests.
10030 mptestsrc=t=dc_luma
10033 will generate a "dc_luma" test pattern.
10035 @section frei0r_src
10037 Provide a frei0r source.
10039 To enable compilation of this filter you need to install the frei0r
10040 header and configure FFmpeg with @code{--enable-frei0r}.
10042 This source accepts the following parameters:
10047 The size of the video to generate. For the syntax of this option, check the
10048 "Video size" section in the ffmpeg-utils manual.
10051 The framerate of the generated video. It may be a string of the form
10052 @var{num}/@var{den} or a frame rate abbreviation.
10055 The name to the frei0r source to load. For more information regarding frei0r and
10056 how to set the parameters, read the @ref{frei0r} section in the video filters
10059 @item filter_params
10060 A '|'-separated list of parameters to pass to the frei0r source.
10064 For example, to generate a frei0r partik0l source with size 200x200
10065 and frame rate 10 which is overlaid on the overlay filter main input:
10067 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
10072 Generate a life pattern.
10074 This source is based on a generalization of John Conway's life game.
10076 The sourced input represents a life grid, each pixel represents a cell
10077 which can be in one of two possible states, alive or dead. Every cell
10078 interacts with its eight neighbours, which are the cells that are
10079 horizontally, vertically, or diagonally adjacent.
10081 At each interaction the grid evolves according to the adopted rule,
10082 which specifies the number of neighbor alive cells which will make a
10083 cell stay alive or born. The @option{rule} option allows one to specify
10086 This source accepts the following options:
10090 Set the file from which to read the initial grid state. In the file,
10091 each non-whitespace character is considered an alive cell, and newline
10092 is used to delimit the end of each row.
10094 If this option is not specified, the initial grid is generated
10098 Set the video rate, that is the number of frames generated per second.
10101 @item random_fill_ratio, ratio
10102 Set the random fill ratio for the initial random grid. It is a
10103 floating point number value ranging from 0 to 1, defaults to 1/PHI.
10104 It is ignored when a file is specified.
10106 @item random_seed, seed
10107 Set the seed for filling the initial random grid, must be an integer
10108 included between 0 and UINT32_MAX. If not specified, or if explicitly
10109 set to -1, the filter will try to use a good random seed on a best
10115 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
10116 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
10117 @var{NS} specifies the number of alive neighbor cells which make a
10118 live cell stay alive, and @var{NB} the number of alive neighbor cells
10119 which make a dead cell to become alive (i.e. to "born").
10120 "s" and "b" can be used in place of "S" and "B", respectively.
10122 Alternatively a rule can be specified by an 18-bits integer. The 9
10123 high order bits are used to encode the next cell state if it is alive
10124 for each number of neighbor alive cells, the low order bits specify
10125 the rule for "borning" new cells. Higher order bits encode for an
10126 higher number of neighbor cells.
10127 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
10128 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
10130 Default value is "S23/B3", which is the original Conway's game of life
10131 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
10132 cells, and will born a new cell if there are three alive cells around
10136 Set the size of the output video. For the syntax of this option, check the
10137 "Video size" section in the ffmpeg-utils manual.
10139 If @option{filename} is specified, the size is set by default to the
10140 same size of the input file. If @option{size} is set, it must contain
10141 the size specified in the input file, and the initial grid defined in
10142 that file is centered in the larger resulting area.
10144 If a filename is not specified, the size value defaults to "320x240"
10145 (used for a randomly generated initial grid).
10148 If set to 1, stitch the left and right grid edges together, and the
10149 top and bottom edges also. Defaults to 1.
10152 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
10153 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
10154 value from 0 to 255.
10157 Set the color of living (or new born) cells.
10160 Set the color of dead cells. If @option{mold} is set, this is the first color
10161 used to represent a dead cell.
10164 Set mold color, for definitely dead and moldy cells.
10166 For the syntax of these 3 color options, check the "Color" section in the
10167 ffmpeg-utils manual.
10170 @subsection Examples
10174 Read a grid from @file{pattern}, and center it on a grid of size
10177 life=f=pattern:s=300x300
10181 Generate a random grid of size 200x200, with a fill ratio of 2/3:
10183 life=ratio=2/3:s=200x200
10187 Specify a custom rule for evolving a randomly generated grid:
10193 Full example with slow death effect (mold) using @command{ffplay}:
10195 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
10200 @anchor{haldclutsrc}
10202 @anchor{rgbtestsrc}
10204 @anchor{smptehdbars}
10206 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
10208 The @code{color} source provides an uniformly colored input.
10210 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
10211 @ref{haldclut} filter.
10213 The @code{nullsrc} source returns unprocessed video frames. It is
10214 mainly useful to be employed in analysis / debugging tools, or as the
10215 source for filters which ignore the input data.
10217 The @code{rgbtestsrc} source generates an RGB test pattern useful for
10218 detecting RGB vs BGR issues. You should see a red, green and blue
10219 stripe from top to bottom.
10221 The @code{smptebars} source generates a color bars pattern, based on
10222 the SMPTE Engineering Guideline EG 1-1990.
10224 The @code{smptehdbars} source generates a color bars pattern, based on
10225 the SMPTE RP 219-2002.
10227 The @code{testsrc} source generates a test video pattern, showing a
10228 color pattern, a scrolling gradient and a timestamp. This is mainly
10229 intended for testing purposes.
10231 The sources accept the following parameters:
10236 Specify the color of the source, only available in the @code{color}
10237 source. For the syntax of this option, check the "Color" section in the
10238 ffmpeg-utils manual.
10241 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
10242 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
10243 pixels to be used as identity matrix for 3D lookup tables. Each component is
10244 coded on a @code{1/(N*N)} scale.
10247 Specify the size of the sourced video. For the syntax of this option, check the
10248 "Video size" section in the ffmpeg-utils manual. The default value is
10251 This option is not available with the @code{haldclutsrc} filter.
10254 Specify the frame rate of the sourced video, as the number of frames
10255 generated per second. It has to be a string in the format
10256 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
10257 number or a valid video frame rate abbreviation. The default value is
10261 Set the sample aspect ratio of the sourced video.
10264 Set the duration of the sourced video. See
10265 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
10266 for the accepted syntax.
10268 If not specified, or the expressed duration is negative, the video is
10269 supposed to be generated forever.
10272 Set the number of decimals to show in the timestamp, only available in the
10273 @code{testsrc} source.
10275 The displayed timestamp value will correspond to the original
10276 timestamp value multiplied by the power of 10 of the specified
10277 value. Default value is 0.
10280 For example the following:
10282 testsrc=duration=5.3:size=qcif:rate=10
10285 will generate a video with a duration of 5.3 seconds, with size
10286 176x144 and a frame rate of 10 frames per second.
10288 The following graph description will generate a red source
10289 with an opacity of 0.2, with size "qcif" and a frame rate of 10
10292 color=c=red@@0.2:s=qcif:r=10
10295 If the input content is to be ignored, @code{nullsrc} can be used. The
10296 following command generates noise in the luminance plane by employing
10297 the @code{geq} filter:
10299 nullsrc=s=256x256, geq=random(1)*255:128:128
10302 @subsection Commands
10304 The @code{color} source supports the following commands:
10308 Set the color of the created image. Accepts the same syntax of the
10309 corresponding @option{color} option.
10312 @c man end VIDEO SOURCES
10314 @chapter Video Sinks
10315 @c man begin VIDEO SINKS
10317 Below is a description of the currently available video sinks.
10319 @section buffersink
10321 Buffer video frames, and make them available to the end of the filter
10324 This sink is mainly intended for programmatic use, in particular
10325 through the interface defined in @file{libavfilter/buffersink.h}
10326 or the options system.
10328 It accepts a pointer to an AVBufferSinkContext structure, which
10329 defines the incoming buffers' formats, to be passed as the opaque
10330 parameter to @code{avfilter_init_filter} for initialization.
10334 Null video sink: do absolutely nothing with the input video. It is
10335 mainly useful as a template and for use in analysis / debugging
10338 @c man end VIDEO SINKS
10340 @chapter Multimedia Filters
10341 @c man begin MULTIMEDIA FILTERS
10343 Below is a description of the currently available multimedia filters.
10345 @section avectorscope
10347 Convert input audio to a video output, representing the audio vector
10350 The filter is used to measure the difference between channels of stereo
10351 audio stream. A monoaural signal, consisting of identical left and right
10352 signal, results in straight vertical line. Any stereo separation is visible
10353 as a deviation from this line, creating a Lissajous figure.
10354 If the straight (or deviation from it) but horizontal line appears this
10355 indicates that the left and right channels are out of phase.
10357 The filter accepts the following options:
10361 Set the vectorscope mode.
10363 Available values are:
10366 Lissajous rotated by 45 degrees.
10369 Same as above but not rotated.
10372 Default value is @samp{lissajous}.
10375 Set the video size for the output. For the syntax of this option, check the "Video size"
10376 section in the ffmpeg-utils manual. Default value is @code{400x400}.
10379 Set the output frame rate. Default value is @code{25}.
10384 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
10385 Allowed range is @code{[0, 255]}.
10390 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
10391 Allowed range is @code{[0, 255]}.
10394 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
10397 @subsection Examples
10401 Complete example using @command{ffplay}:
10403 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10404 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
10410 Concatenate audio and video streams, joining them together one after the
10413 The filter works on segments of synchronized video and audio streams. All
10414 segments must have the same number of streams of each type, and that will
10415 also be the number of streams at output.
10417 The filter accepts the following options:
10422 Set the number of segments. Default is 2.
10425 Set the number of output video streams, that is also the number of video
10426 streams in each segment. Default is 1.
10429 Set the number of output audio streams, that is also the number of audio
10430 streams in each segment. Default is 0.
10433 Activate unsafe mode: do not fail if segments have a different format.
10437 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
10438 @var{a} audio outputs.
10440 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
10441 segment, in the same order as the outputs, then the inputs for the second
10444 Related streams do not always have exactly the same duration, for various
10445 reasons including codec frame size or sloppy authoring. For that reason,
10446 related synchronized streams (e.g. a video and its audio track) should be
10447 concatenated at once. The concat filter will use the duration of the longest
10448 stream in each segment (except the last one), and if necessary pad shorter
10449 audio streams with silence.
10451 For this filter to work correctly, all segments must start at timestamp 0.
10453 All corresponding streams must have the same parameters in all segments; the
10454 filtering system will automatically select a common pixel format for video
10455 streams, and a common sample format, sample rate and channel layout for
10456 audio streams, but other settings, such as resolution, must be converted
10457 explicitly by the user.
10459 Different frame rates are acceptable but will result in variable frame rate
10460 at output; be sure to configure the output file to handle it.
10462 @subsection Examples
10466 Concatenate an opening, an episode and an ending, all in bilingual version
10467 (video in stream 0, audio in streams 1 and 2):
10469 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
10470 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
10471 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
10472 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
10476 Concatenate two parts, handling audio and video separately, using the
10477 (a)movie sources, and adjusting the resolution:
10479 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
10480 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
10481 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
10483 Note that a desync will happen at the stitch if the audio and video streams
10484 do not have exactly the same duration in the first file.
10490 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
10491 it unchanged. By default, it logs a message at a frequency of 10Hz with the
10492 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
10493 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
10495 The filter also has a video output (see the @var{video} option) with a real
10496 time graph to observe the loudness evolution. The graphic contains the logged
10497 message mentioned above, so it is not printed anymore when this option is set,
10498 unless the verbose logging is set. The main graphing area contains the
10499 short-term loudness (3 seconds of analysis), and the gauge on the right is for
10500 the momentary loudness (400 milliseconds).
10502 More information about the Loudness Recommendation EBU R128 on
10503 @url{http://tech.ebu.ch/loudness}.
10505 The filter accepts the following options:
10510 Activate the video output. The audio stream is passed unchanged whether this
10511 option is set or no. The video stream will be the first output stream if
10512 activated. Default is @code{0}.
10515 Set the video size. This option is for video only. For the syntax of this
10516 option, check the "Video size" section in the ffmpeg-utils manual. Default
10517 and minimum resolution is @code{640x480}.
10520 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
10521 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
10522 other integer value between this range is allowed.
10525 Set metadata injection. If set to @code{1}, the audio input will be segmented
10526 into 100ms output frames, each of them containing various loudness information
10527 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
10529 Default is @code{0}.
10532 Force the frame logging level.
10534 Available values are:
10537 information logging level
10539 verbose logging level
10542 By default, the logging level is set to @var{info}. If the @option{video} or
10543 the @option{metadata} options are set, it switches to @var{verbose}.
10548 Available modes can be cumulated (the option is a @code{flag} type). Possible
10552 Disable any peak mode (default).
10554 Enable sample-peak mode.
10556 Simple peak mode looking for the higher sample value. It logs a message
10557 for sample-peak (identified by @code{SPK}).
10559 Enable true-peak mode.
10561 If enabled, the peak lookup is done on an over-sampled version of the input
10562 stream for better peak accuracy. It logs a message for true-peak.
10563 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
10564 This mode requires a build with @code{libswresample}.
10569 @subsection Examples
10573 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
10575 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
10579 Run an analysis with @command{ffmpeg}:
10581 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
10585 @section interleave, ainterleave
10587 Temporally interleave frames from several inputs.
10589 @code{interleave} works with video inputs, @code{ainterleave} with audio.
10591 These filters read frames from several inputs and send the oldest
10592 queued frame to the output.
10594 Input streams must have a well defined, monotonically increasing frame
10597 In order to submit one frame to output, these filters need to enqueue
10598 at least one frame for each input, so they cannot work in case one
10599 input is not yet terminated and will not receive incoming frames.
10601 For example consider the case when one input is a @code{select} filter
10602 which always drop input frames. The @code{interleave} filter will keep
10603 reading from that input, but it will never be able to send new frames
10604 to output until the input will send an end-of-stream signal.
10606 Also, depending on inputs synchronization, the filters will drop
10607 frames in case one input receives more frames than the other ones, and
10608 the queue is already filled.
10610 These filters accept the following options:
10614 Set the number of different inputs, it is 2 by default.
10617 @subsection Examples
10621 Interleave frames belonging to different streams using @command{ffmpeg}:
10623 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
10627 Add flickering blur effect:
10629 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
10633 @section perms, aperms
10635 Set read/write permissions for the output frames.
10637 These filters are mainly aimed at developers to test direct path in the
10638 following filter in the filtergraph.
10640 The filters accept the following options:
10644 Select the permissions mode.
10646 It accepts the following values:
10649 Do nothing. This is the default.
10651 Set all the output frames read-only.
10653 Set all the output frames directly writable.
10655 Make the frame read-only if writable, and writable if read-only.
10657 Set each output frame read-only or writable randomly.
10661 Set the seed for the @var{random} mode, must be an integer included between
10662 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
10663 @code{-1}, the filter will try to use a good random seed on a best effort
10667 Note: in case of auto-inserted filter between the permission filter and the
10668 following one, the permission might not be received as expected in that
10669 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
10670 perms/aperms filter can avoid this problem.
10672 @section select, aselect
10674 Select frames to pass in output.
10676 This filter accepts the following options:
10681 Set expression, which is evaluated for each input frame.
10683 If the expression is evaluated to zero, the frame is discarded.
10685 If the evaluation result is negative or NaN, the frame is sent to the
10686 first output; otherwise it is sent to the output with index
10687 @code{ceil(val)-1}, assuming that the input index starts from 0.
10689 For example a value of @code{1.2} corresponds to the output with index
10690 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
10693 Set the number of outputs. The output to which to send the selected
10694 frame is based on the result of the evaluation. Default value is 1.
10697 The expression can contain the following constants:
10701 The (sequential) number of the filtered frame, starting from 0.
10704 The (sequential) number of the selected frame, starting from 0.
10706 @item prev_selected_n
10707 The sequential number of the last selected frame. It's NAN if undefined.
10710 The timebase of the input timestamps.
10713 The PTS (Presentation TimeStamp) of the filtered video frame,
10714 expressed in @var{TB} units. It's NAN if undefined.
10717 The PTS of the filtered video frame,
10718 expressed in seconds. It's NAN if undefined.
10721 The PTS of the previously filtered video frame. It's NAN if undefined.
10723 @item prev_selected_pts
10724 The PTS of the last previously filtered video frame. It's NAN if undefined.
10726 @item prev_selected_t
10727 The PTS of the last previously selected video frame. It's NAN if undefined.
10730 The PTS of the first video frame in the video. It's NAN if undefined.
10733 The time of the first video frame in the video. It's NAN if undefined.
10735 @item pict_type @emph{(video only)}
10736 The type of the filtered frame. It can assume one of the following
10748 @item interlace_type @emph{(video only)}
10749 The frame interlace type. It can assume one of the following values:
10752 The frame is progressive (not interlaced).
10754 The frame is top-field-first.
10756 The frame is bottom-field-first.
10759 @item consumed_sample_n @emph{(audio only)}
10760 the number of selected samples before the current frame
10762 @item samples_n @emph{(audio only)}
10763 the number of samples in the current frame
10765 @item sample_rate @emph{(audio only)}
10766 the input sample rate
10769 This is 1 if the filtered frame is a key-frame, 0 otherwise.
10772 the position in the file of the filtered frame, -1 if the information
10773 is not available (e.g. for synthetic video)
10775 @item scene @emph{(video only)}
10776 value between 0 and 1 to indicate a new scene; a low value reflects a low
10777 probability for the current frame to introduce a new scene, while a higher
10778 value means the current frame is more likely to be one (see the example below)
10782 The default value of the select expression is "1".
10784 @subsection Examples
10788 Select all frames in input:
10793 The example above is the same as:
10805 Select only I-frames:
10807 select='eq(pict_type\,I)'
10811 Select one frame every 100:
10813 select='not(mod(n\,100))'
10817 Select only frames contained in the 10-20 time interval:
10819 select=between(t\,10\,20)
10823 Select only I frames contained in the 10-20 time interval:
10825 select=between(t\,10\,20)*eq(pict_type\,I)
10829 Select frames with a minimum distance of 10 seconds:
10831 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
10835 Use aselect to select only audio frames with samples number > 100:
10837 aselect='gt(samples_n\,100)'
10841 Create a mosaic of the first scenes:
10843 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
10846 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
10850 Send even and odd frames to separate outputs, and compose them:
10852 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
10856 @section sendcmd, asendcmd
10858 Send commands to filters in the filtergraph.
10860 These filters read commands to be sent to other filters in the
10863 @code{sendcmd} must be inserted between two video filters,
10864 @code{asendcmd} must be inserted between two audio filters, but apart
10865 from that they act the same way.
10867 The specification of commands can be provided in the filter arguments
10868 with the @var{commands} option, or in a file specified by the
10869 @var{filename} option.
10871 These filters accept the following options:
10874 Set the commands to be read and sent to the other filters.
10876 Set the filename of the commands to be read and sent to the other
10880 @subsection Commands syntax
10882 A commands description consists of a sequence of interval
10883 specifications, comprising a list of commands to be executed when a
10884 particular event related to that interval occurs. The occurring event
10885 is typically the current frame time entering or leaving a given time
10888 An interval is specified by the following syntax:
10890 @var{START}[-@var{END}] @var{COMMANDS};
10893 The time interval is specified by the @var{START} and @var{END} times.
10894 @var{END} is optional and defaults to the maximum time.
10896 The current frame time is considered within the specified interval if
10897 it is included in the interval [@var{START}, @var{END}), that is when
10898 the time is greater or equal to @var{START} and is lesser than
10901 @var{COMMANDS} consists of a sequence of one or more command
10902 specifications, separated by ",", relating to that interval. The
10903 syntax of a command specification is given by:
10905 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
10908 @var{FLAGS} is optional and specifies the type of events relating to
10909 the time interval which enable sending the specified command, and must
10910 be a non-null sequence of identifier flags separated by "+" or "|" and
10911 enclosed between "[" and "]".
10913 The following flags are recognized:
10916 The command is sent when the current frame timestamp enters the
10917 specified interval. In other words, the command is sent when the
10918 previous frame timestamp was not in the given interval, and the
10922 The command is sent when the current frame timestamp leaves the
10923 specified interval. In other words, the command is sent when the
10924 previous frame timestamp was in the given interval, and the
10928 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
10931 @var{TARGET} specifies the target of the command, usually the name of
10932 the filter class or a specific filter instance name.
10934 @var{COMMAND} specifies the name of the command for the target filter.
10936 @var{ARG} is optional and specifies the optional list of argument for
10937 the given @var{COMMAND}.
10939 Between one interval specification and another, whitespaces, or
10940 sequences of characters starting with @code{#} until the end of line,
10941 are ignored and can be used to annotate comments.
10943 A simplified BNF description of the commands specification syntax
10946 @var{COMMAND_FLAG} ::= "enter" | "leave"
10947 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
10948 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
10949 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
10950 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
10951 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
10954 @subsection Examples
10958 Specify audio tempo change at second 4:
10960 asendcmd=c='4.0 atempo tempo 1.5',atempo
10964 Specify a list of drawtext and hue commands in a file.
10966 # show text in the interval 5-10
10967 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
10968 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
10970 # desaturate the image in the interval 15-20
10971 15.0-20.0 [enter] hue s 0,
10972 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
10974 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
10976 # apply an exponential saturation fade-out effect, starting from time 25
10977 25 [enter] hue s exp(25-t)
10980 A filtergraph allowing to read and process the above command list
10981 stored in a file @file{test.cmd}, can be specified with:
10983 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
10988 @section setpts, asetpts
10990 Change the PTS (presentation timestamp) of the input frames.
10992 @code{setpts} works on video frames, @code{asetpts} on audio frames.
10994 This filter accepts the following options:
10999 The expression which is evaluated for each frame to construct its timestamp.
11003 The expression is evaluated through the eval API and can contain the following
11008 frame rate, only defined for constant frame-rate video
11011 The presentation timestamp in input
11014 The count of the input frame for video or the number of consumed samples,
11015 not including the current frame for audio, starting from 0.
11017 @item NB_CONSUMED_SAMPLES
11018 The number of consumed samples, not including the current frame (only
11021 @item NB_SAMPLES, S
11022 The number of samples in the current frame (only audio)
11024 @item SAMPLE_RATE, SR
11025 The audio sample rate.
11028 The PTS of the first frame.
11031 the time in seconds of the first frame
11034 State whether the current frame is interlaced.
11037 the time in seconds of the current frame
11040 original position in the file of the frame, or undefined if undefined
11041 for the current frame
11044 The previous input PTS.
11047 previous input time in seconds
11050 The previous output PTS.
11053 previous output time in seconds
11056 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
11060 The wallclock (RTC) time at the start of the movie in microseconds.
11063 The timebase of the input timestamps.
11067 @subsection Examples
11071 Start counting PTS from zero
11073 setpts=PTS-STARTPTS
11077 Apply fast motion effect:
11083 Apply slow motion effect:
11089 Set fixed rate of 25 frames per second:
11095 Set fixed rate 25 fps with some jitter:
11097 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
11101 Apply an offset of 10 seconds to the input PTS:
11107 Generate timestamps from a "live source" and rebase onto the current timebase:
11109 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
11113 Generate timestamps by counting samples:
11120 @section settb, asettb
11122 Set the timebase to use for the output frames timestamps.
11123 It is mainly useful for testing timebase configuration.
11125 It accepts the following parameters:
11130 The expression which is evaluated into the output timebase.
11134 The value for @option{tb} is an arithmetic expression representing a
11135 rational. The expression can contain the constants "AVTB" (the default
11136 timebase), "intb" (the input timebase) and "sr" (the sample rate,
11137 audio only). Default value is "intb".
11139 @subsection Examples
11143 Set the timebase to 1/25:
11149 Set the timebase to 1/10:
11155 Set the timebase to 1001/1000:
11161 Set the timebase to 2*intb:
11167 Set the default timebase value:
11174 Convert input audio to a video output representing
11175 frequency spectrum logarithmically (using constant Q transform with
11176 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
11178 The filter accepts the following options:
11182 Specify transform volume (multiplier) expression. The expression can contain
11185 @item frequency, freq, f
11186 the frequency where transform is evaluated
11187 @item timeclamp, tc
11188 value of timeclamp option
11192 @item a_weighting(f)
11193 A-weighting of equal loudness
11194 @item b_weighting(f)
11195 B-weighting of equal loudness
11196 @item c_weighting(f)
11197 C-weighting of equal loudness
11199 Default value is @code{16}.
11202 Specify transform length expression. The expression can contain variables:
11204 @item frequency, freq, f
11205 the frequency where transform is evaluated
11206 @item timeclamp, tc
11207 value of timeclamp option
11209 Default value is @code{384/f*tc/(384/f+tc)}.
11212 Specify the transform timeclamp. At low frequency, there is trade-off between
11213 accuracy in time domain and frequency domain. If timeclamp is lower,
11214 event in time domain is represented more accurately (such as fast bass drum),
11215 otherwise event in frequency domain is represented more accurately
11216 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
11219 Specify the transform coeffclamp. If coeffclamp is lower, transform is
11220 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
11221 Default value is @code{1.0}.
11224 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
11225 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
11226 Default value is @code{3.0}.
11229 Specify gamma of bargraph. Acceptable value is [1.0, 7.0].
11230 Default value is @code{1.0}.
11233 Specify font file for use with freetype. If not specified, use embedded font.
11236 Specify font color expression. This is arithmetic expression that should return
11237 integer value 0xRRGGBB. The expression can contain variables:
11239 @item frequency, freq, f
11240 the frequency where transform is evaluated
11241 @item timeclamp, tc
11242 value of timeclamp option
11247 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
11248 @item r(x), g(x), b(x)
11249 red, green, and blue value of intensity x
11251 Default value is @code{st(0, (midi(f)-59.5)/12);
11252 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
11253 r(1-ld(1)) + b(ld(1))}
11256 If set to 1 (the default), the video size is 1920x1080 (full HD),
11257 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
11260 Specify video fps. Default value is @code{25}.
11263 Specify number of transform per frame, so there are fps*count transforms
11264 per second. Note that audio data rate must be divisible by fps*count.
11265 Default value is @code{6}.
11269 @subsection Examples
11273 Playing audio while showing the spectrum:
11275 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
11279 Same as above, but with frame rate 30 fps:
11281 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
11285 Playing at 960x540 and lower CPU usage:
11287 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
11291 A1 and its harmonics: A1, A2, (near)E3, A3:
11293 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),
11294 asplit[a][out1]; [a] showcqt [out0]'
11298 Same as above, but with more accuracy in frequency domain (and slower):
11300 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),
11301 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
11305 B-weighting of equal loudness
11307 volume=16*b_weighting(f)
11313 tlength=100/f*tc/(100/f+tc)
11317 Custom fontcolor, C-note is colored green, others are colored blue
11319 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))'
11323 Custom gamma, now spectrum is linear to the amplitude.
11330 @section showspectrum
11332 Convert input audio to a video output, representing the audio frequency
11335 The filter accepts the following options:
11339 Specify the video size for the output. For the syntax of this option, check
11340 the "Video size" section in the ffmpeg-utils manual. Default value is
11344 Specify how the spectrum should slide along the window.
11346 It accepts the following values:
11349 the samples start again on the left when they reach the right
11351 the samples scroll from right to left
11353 frames are only produced when the samples reach the right
11356 Default value is @code{replace}.
11359 Specify display mode.
11361 It accepts the following values:
11364 all channels are displayed in the same row
11366 all channels are displayed in separate rows
11369 Default value is @samp{combined}.
11372 Specify display color mode.
11374 It accepts the following values:
11377 each channel is displayed in a separate color
11379 each channel is is displayed using the same color scheme
11382 Default value is @samp{channel}.
11385 Specify scale used for calculating intensity color values.
11387 It accepts the following values:
11392 square root, default
11399 Default value is @samp{sqrt}.
11402 Set saturation modifier for displayed colors. Negative values provide
11403 alternative color scheme. @code{0} is no saturation at all.
11404 Saturation must be in [-10.0, 10.0] range.
11405 Default value is @code{1}.
11408 Set window function.
11410 It accepts the following values:
11413 No samples pre-processing (do not expect this to be faster)
11422 Default value is @code{hann}.
11425 The usage is very similar to the showwaves filter; see the examples in that
11428 @subsection Examples
11432 Large window with logarithmic color scaling:
11434 showspectrum=s=1280x480:scale=log
11438 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
11440 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
11441 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
11447 Convert input audio to a video output, representing the samples waves.
11449 The filter accepts the following options:
11453 Specify the video size for the output. For the syntax of this option, check
11454 the "Video size" section in the ffmpeg-utils manual. Default value
11460 Available values are:
11463 Draw a point for each sample.
11466 Draw a vertical line for each sample.
11469 Draw a point for each sample and a line between them.
11472 Draw a centered vertical line for each sample.
11475 Default value is @code{point}.
11478 Set the number of samples which are printed on the same column. A
11479 larger value will decrease the frame rate. Must be a positive
11480 integer. This option can be set only if the value for @var{rate}
11481 is not explicitly specified.
11484 Set the (approximate) output frame rate. This is done by setting the
11485 option @var{n}. Default value is "25".
11487 @item split_channels
11488 Set if channels should be drawn separately or overlap. Default value is 0.
11492 @subsection Examples
11496 Output the input file audio and the corresponding video representation
11499 amovie=a.mp3,asplit[out0],showwaves[out1]
11503 Create a synthetic signal and show it with showwaves, forcing a
11504 frame rate of 30 frames per second:
11506 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
11510 @section split, asplit
11512 Split input into several identical outputs.
11514 @code{asplit} works with audio input, @code{split} with video.
11516 The filter accepts a single parameter which specifies the number of outputs. If
11517 unspecified, it defaults to 2.
11519 @subsection Examples
11523 Create two separate outputs from the same input:
11525 [in] split [out0][out1]
11529 To create 3 or more outputs, you need to specify the number of
11532 [in] asplit=3 [out0][out1][out2]
11536 Create two separate outputs from the same input, one cropped and
11539 [in] split [splitout1][splitout2];
11540 [splitout1] crop=100:100:0:0 [cropout];
11541 [splitout2] pad=200:200:100:100 [padout];
11545 Create 5 copies of the input audio with @command{ffmpeg}:
11547 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
11553 Receive commands sent through a libzmq client, and forward them to
11554 filters in the filtergraph.
11556 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
11557 must be inserted between two video filters, @code{azmq} between two
11560 To enable these filters you need to install the libzmq library and
11561 headers and configure FFmpeg with @code{--enable-libzmq}.
11563 For more information about libzmq see:
11564 @url{http://www.zeromq.org/}
11566 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
11567 receives messages sent through a network interface defined by the
11568 @option{bind_address} option.
11570 The received message must be in the form:
11572 @var{TARGET} @var{COMMAND} [@var{ARG}]
11575 @var{TARGET} specifies the target of the command, usually the name of
11576 the filter class or a specific filter instance name.
11578 @var{COMMAND} specifies the name of the command for the target filter.
11580 @var{ARG} is optional and specifies the optional argument list for the
11581 given @var{COMMAND}.
11583 Upon reception, the message is processed and the corresponding command
11584 is injected into the filtergraph. Depending on the result, the filter
11585 will send a reply to the client, adopting the format:
11587 @var{ERROR_CODE} @var{ERROR_REASON}
11591 @var{MESSAGE} is optional.
11593 @subsection Examples
11595 Look at @file{tools/zmqsend} for an example of a zmq client which can
11596 be used to send commands processed by these filters.
11598 Consider the following filtergraph generated by @command{ffplay}
11600 ffplay -dumpgraph 1 -f lavfi "
11601 color=s=100x100:c=red [l];
11602 color=s=100x100:c=blue [r];
11603 nullsrc=s=200x100, zmq [bg];
11604 [bg][l] overlay [bg+l];
11605 [bg+l][r] overlay=x=100 "
11608 To change the color of the left side of the video, the following
11609 command can be used:
11611 echo Parsed_color_0 c yellow | tools/zmqsend
11614 To change the right side:
11616 echo Parsed_color_1 c pink | tools/zmqsend
11619 @c man end MULTIMEDIA FILTERS
11621 @chapter Multimedia Sources
11622 @c man begin MULTIMEDIA SOURCES
11624 Below is a description of the currently available multimedia sources.
11628 This is the same as @ref{movie} source, except it selects an audio
11634 Read audio and/or video stream(s) from a movie container.
11636 It accepts the following parameters:
11640 The name of the resource to read (not necessarily a file; it can also be a
11641 device or a stream accessed through some protocol).
11643 @item format_name, f
11644 Specifies the format assumed for the movie to read, and can be either
11645 the name of a container or an input device. If not specified, the
11646 format is guessed from @var{movie_name} or by probing.
11648 @item seek_point, sp
11649 Specifies the seek point in seconds. The frames will be output
11650 starting from this seek point. The parameter is evaluated with
11651 @code{av_strtod}, so the numerical value may be suffixed by an IS
11652 postfix. The default value is "0".
11655 Specifies the streams to read. Several streams can be specified,
11656 separated by "+". The source will then have as many outputs, in the
11657 same order. The syntax is explained in the ``Stream specifiers''
11658 section in the ffmpeg manual. Two special names, "dv" and "da" specify
11659 respectively the default (best suited) video and audio stream. Default
11660 is "dv", or "da" if the filter is called as "amovie".
11662 @item stream_index, si
11663 Specifies the index of the video stream to read. If the value is -1,
11664 the most suitable video stream will be automatically selected. The default
11665 value is "-1". Deprecated. If the filter is called "amovie", it will select
11666 audio instead of video.
11669 Specifies how many times to read the stream in sequence.
11670 If the value is less than 1, the stream will be read again and again.
11671 Default value is "1".
11673 Note that when the movie is looped the source timestamps are not
11674 changed, so it will generate non monotonically increasing timestamps.
11677 It allows overlaying a second video on top of the main input of
11678 a filtergraph, as shown in this graph:
11680 input -----------> deltapts0 --> overlay --> output
11683 movie --> scale--> deltapts1 -------+
11685 @subsection Examples
11689 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
11690 on top of the input labelled "in":
11692 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
11693 [in] setpts=PTS-STARTPTS [main];
11694 [main][over] overlay=16:16 [out]
11698 Read from a video4linux2 device, and overlay it on top of the input
11701 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
11702 [in] setpts=PTS-STARTPTS [main];
11703 [main][over] overlay=16:16 [out]
11707 Read the first video stream and the audio stream with id 0x81 from
11708 dvd.vob; the video is connected to the pad named "video" and the audio is
11709 connected to the pad named "audio":
11711 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
11715 @c man end MULTIMEDIA SOURCES