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 @samp{'} as initial
169 and ending mark, and the character @samp{\} 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 @samp{[]=;,}) 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
540 select inverted quarter of sine wave
542 select inverted half of sine wave
544 select double-exponential seat
546 select double-exponential sigmoid
554 Fade in first 15 seconds of audio:
560 Fade out last 25 seconds of a 900 seconds audio:
562 afade=t=out:st=875:d=25
569 Set output format constraints for the input audio. The framework will
570 negotiate the most appropriate format to minimize conversions.
572 It accepts the following parameters:
576 A '|'-separated list of requested sample formats.
579 A '|'-separated list of requested sample rates.
581 @item channel_layouts
582 A '|'-separated list of requested channel layouts.
584 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
585 for the required syntax.
588 If a parameter is omitted, all values are allowed.
590 Force the output to either unsigned 8-bit or signed 16-bit stereo
592 aformat=sample_fmts=u8|s16:channel_layouts=stereo
597 Apply a two-pole all-pass filter with central frequency (in Hz)
598 @var{frequency}, and filter-width @var{width}.
599 An all-pass filter changes the audio's frequency to phase relationship
600 without changing its frequency to amplitude relationship.
602 The filter accepts the following options:
609 Set method to specify band-width of filter.
622 Specify the band-width of a filter in width_type units.
627 Merge two or more audio streams into a single multi-channel stream.
629 The filter accepts the following options:
634 Set the number of inputs. Default is 2.
638 If the channel layouts of the inputs are disjoint, and therefore compatible,
639 the channel layout of the output will be set accordingly and the channels
640 will be reordered as necessary. If the channel layouts of the inputs are not
641 disjoint, the output will have all the channels of the first input then all
642 the channels of the second input, in that order, and the channel layout of
643 the output will be the default value corresponding to the total number of
646 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
647 is FC+BL+BR, then the output will be in 5.1, with the channels in the
648 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
649 first input, b1 is the first channel of the second input).
651 On the other hand, if both input are in stereo, the output channels will be
652 in the default order: a1, a2, b1, b2, and the channel layout will be
653 arbitrarily set to 4.0, which may or may not be the expected value.
655 All inputs must have the same sample rate, and format.
657 If inputs do not have the same duration, the output will stop with the
664 Merge two mono files into a stereo stream:
666 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
670 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
672 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
678 Mixes multiple audio inputs into a single output.
680 Note that this filter only supports float samples (the @var{amerge}
681 and @var{pan} audio filters support many formats). If the @var{amix}
682 input has integer samples then @ref{aresample} will be automatically
683 inserted to perform the conversion to float samples.
687 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
689 will mix 3 input audio streams to a single output with the same duration as the
690 first input and a dropout transition time of 3 seconds.
692 It accepts the following parameters:
696 The number of inputs. If unspecified, it defaults to 2.
699 How to determine the end-of-stream.
703 The duration of the longest input. (default)
706 The duration of the shortest input.
709 The duration of the first input.
713 @item dropout_transition
714 The transition time, in seconds, for volume renormalization when an input
715 stream ends. The default value is 2 seconds.
721 Pass the audio source unchanged to the output.
725 Pad the end of an audio stream with silence.
727 This can be used together with @command{ffmpeg} @option{-shortest} to
728 extend audio streams to the same length as the video stream.
730 A description of the accepted options follows.
734 Set silence packet size. Default value is 4096.
737 Set the number of samples of silence to add to the end. After the
738 value is reached, the stream is terminated. This option is mutually
739 exclusive with @option{whole_len}.
742 Set the minimum total number of samples in the output audio stream. If
743 the value is longer than the input audio length, silence is added to
744 the end, until the value is reached. This option is mutually exclusive
745 with @option{pad_len}.
748 If neither the @option{pad_len} nor the @option{whole_len} option is
749 set, the filter will add silence to the end of the input stream
756 Add 1024 samples of silence to the end of the input:
762 Make sure the audio output will contain at least 10000 samples, pad
763 the input with silence if required:
769 Use @command{ffmpeg} to pad the audio input with silence, so that the
770 video stream will always result the shortest and will be converted
771 until the end in the output file when using the @option{shortest}
774 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
779 Add a phasing effect to the input audio.
781 A phaser filter creates series of peaks and troughs in the frequency spectrum.
782 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
784 A description of the accepted parameters follows.
788 Set input gain. Default is 0.4.
791 Set output gain. Default is 0.74
794 Set delay in milliseconds. Default is 3.0.
797 Set decay. Default is 0.4.
800 Set modulation speed in Hz. Default is 0.5.
803 Set modulation type. Default is triangular.
805 It accepts the following values:
815 Resample the input audio to the specified parameters, using the
816 libswresample library. If none are specified then the filter will
817 automatically convert between its input and output.
819 This filter is also able to stretch/squeeze the audio data to make it match
820 the timestamps or to inject silence / cut out audio to make it match the
821 timestamps, do a combination of both or do neither.
823 The filter accepts the syntax
824 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
825 expresses a sample rate and @var{resampler_options} is a list of
826 @var{key}=@var{value} pairs, separated by ":". See the
827 ffmpeg-resampler manual for the complete list of supported options.
833 Resample the input audio to 44100Hz:
839 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
840 samples per second compensation:
846 @section asetnsamples
848 Set the number of samples per each output audio frame.
850 The last output packet may contain a different number of samples, as
851 the filter will flush all the remaining samples when the input audio
854 The filter accepts the following options:
858 @item nb_out_samples, n
859 Set the number of frames per each output audio frame. The number is
860 intended as the number of samples @emph{per each channel}.
861 Default value is 1024.
864 If set to 1, the filter will pad the last audio frame with zeroes, so
865 that the last frame will contain the same number of samples as the
866 previous ones. Default value is 1.
869 For example, to set the number of per-frame samples to 1234 and
870 disable padding for the last frame, use:
872 asetnsamples=n=1234:p=0
877 Set the sample rate without altering the PCM data.
878 This will result in a change of speed and pitch.
880 The filter accepts the following options:
884 Set the output sample rate. Default is 44100 Hz.
889 Show a line containing various information for each input audio frame.
890 The input audio is not modified.
892 The shown line contains a sequence of key/value pairs of the form
893 @var{key}:@var{value}.
895 The following values are shown in the output:
899 The (sequential) number of the input frame, starting from 0.
902 The presentation timestamp of the input frame, in time base units; the time base
903 depends on the filter input pad, and is usually 1/@var{sample_rate}.
906 The presentation timestamp of the input frame in seconds.
909 position of the frame in the input stream, -1 if this information in
910 unavailable and/or meaningless (for example in case of synthetic audio)
919 The sample rate for the audio frame.
922 The number of samples (per channel) in the frame.
925 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
926 audio, the data is treated as if all the planes were concatenated.
928 @item plane_checksums
929 A list of Adler-32 checksums for each data plane.
935 Display time domain statistical information about the audio channels.
936 Statistics are calculated and displayed for each audio channel and,
937 where applicable, an overall figure is also given.
939 It accepts the following option:
942 Short window length in seconds, used for peak and trough RMS measurement.
943 Default is @code{0.05} (50 milliseconds). Allowed range is @code{[0.1 - 10]}.
946 A description of each shown parameter follows:
950 Mean amplitude displacement from zero.
953 Minimal sample level.
956 Maximal sample level.
960 Standard peak and RMS level measured in dBFS.
964 Peak and trough values for RMS level measured over a short window.
967 Standard ratio of peak to RMS level (note: not in dB).
970 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
971 (i.e. either @var{Min level} or @var{Max level}).
974 Number of occasions (not the number of samples) that the signal attained either
975 @var{Min level} or @var{Max level}.
980 Forward two audio streams and control the order the buffers are forwarded.
982 The filter accepts the following options:
986 Set the expression deciding which stream should be
987 forwarded next: if the result is negative, the first stream is forwarded; if
988 the result is positive or zero, the second stream is forwarded. It can use
989 the following variables:
993 number of buffers forwarded so far on each stream
995 number of samples forwarded so far on each stream
997 current timestamp of each stream
1000 The default value is @code{t1-t2}, which means to always forward the stream
1001 that has a smaller timestamp.
1004 @subsection Examples
1006 Stress-test @code{amerge} by randomly sending buffers on the wrong
1007 input, while avoiding too much of a desynchronization:
1009 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
1010 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
1016 Synchronize audio data with timestamps by squeezing/stretching it and/or
1017 dropping samples/adding silence when needed.
1019 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1021 It accepts the following parameters:
1025 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1026 by default. When disabled, time gaps are covered with silence.
1029 The minimum difference between timestamps and audio data (in seconds) to trigger
1030 adding/dropping samples. The default value is 0.1. If you get an imperfect
1031 sync with this filter, try setting this parameter to 0.
1034 The maximum compensation in samples per second. Only relevant with compensate=1.
1035 The default value is 500.
1038 Assume that the first PTS should be this value. The time base is 1 / sample
1039 rate. This allows for padding/trimming at the start of the stream. By default,
1040 no assumption is made about the first frame's expected PTS, so no padding or
1041 trimming is done. For example, this could be set to 0 to pad the beginning with
1042 silence if an audio stream starts after the video stream or to trim any samples
1043 with a negative PTS due to encoder delay.
1051 The filter accepts exactly one parameter, the audio tempo. If not
1052 specified then the filter will assume nominal 1.0 tempo. Tempo must
1053 be in the [0.5, 2.0] range.
1055 @subsection Examples
1059 Slow down audio to 80% tempo:
1065 To speed up audio to 125% tempo:
1073 Trim the input so that the output contains one continuous subpart of the input.
1075 It accepts the following parameters:
1078 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1079 sample with the timestamp @var{start} will be the first sample in the output.
1082 Specify time of the first audio sample that will be dropped, i.e. the
1083 audio sample immediately preceding the one with the timestamp @var{end} will be
1084 the last sample in the output.
1087 Same as @var{start}, except this option sets the start timestamp in samples
1091 Same as @var{end}, except this option sets the end timestamp in samples instead
1095 The maximum duration of the output in seconds.
1098 The number of the first sample that should be output.
1101 The number of the first sample that should be dropped.
1104 @option{start}, @option{end}, and @option{duration} are expressed as time
1105 duration specifications; see
1106 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
1108 Note that the first two sets of the start/end options and the @option{duration}
1109 option look at the frame timestamp, while the _sample options simply count the
1110 samples that pass through the filter. So start/end_pts and start/end_sample will
1111 give different results when the timestamps are wrong, inexact or do not start at
1112 zero. Also note that this filter does not modify the timestamps. If you wish
1113 to have the output timestamps start at zero, insert the asetpts filter after the
1116 If multiple start or end options are set, this filter tries to be greedy and
1117 keep all samples that match at least one of the specified constraints. To keep
1118 only the part that matches all the constraints at once, chain multiple atrim
1121 The defaults are such that all the input is kept. So it is possible to set e.g.
1122 just the end values to keep everything before the specified time.
1127 Drop everything except the second minute of input:
1129 ffmpeg -i INPUT -af atrim=60:120
1133 Keep only the first 1000 samples:
1135 ffmpeg -i INPUT -af atrim=end_sample=1000
1142 Apply a two-pole Butterworth band-pass filter with central
1143 frequency @var{frequency}, and (3dB-point) band-width width.
1144 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1145 instead of the default: constant 0dB peak gain.
1146 The filter roll off at 6dB per octave (20dB per decade).
1148 The filter accepts the following options:
1152 Set the filter's central frequency. Default is @code{3000}.
1155 Constant skirt gain if set to 1. Defaults to 0.
1158 Set method to specify band-width of filter.
1171 Specify the band-width of a filter in width_type units.
1176 Apply a two-pole Butterworth band-reject filter with central
1177 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1178 The filter roll off at 6dB per octave (20dB per decade).
1180 The filter accepts the following options:
1184 Set the filter's central frequency. Default is @code{3000}.
1187 Set method to specify band-width of filter.
1200 Specify the band-width of a filter in width_type units.
1205 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1206 shelving filter with a response similar to that of a standard
1207 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1209 The filter accepts the following options:
1213 Give the gain at 0 Hz. Its useful range is about -20
1214 (for a large cut) to +20 (for a large boost).
1215 Beware of clipping when using a positive gain.
1218 Set the filter's central frequency and so can be used
1219 to extend or reduce the frequency range to be boosted or cut.
1220 The default value is @code{100} Hz.
1223 Set method to specify band-width of filter.
1236 Determine how steep is the filter's shelf transition.
1241 Apply a biquad IIR filter with the given coefficients.
1242 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1243 are the numerator and denominator coefficients respectively.
1246 Bauer stereo to binaural transformation, which improves headphone listening of
1247 stereo audio records.
1249 It accepts the following parameters:
1253 Pre-defined crossfeed level.
1257 Default level (fcut=700, feed=50).
1260 Chu Moy circuit (fcut=700, feed=60).
1263 Jan Meier circuit (fcut=650, feed=95).
1268 Cut frequency (in Hz).
1277 Remap input channels to new locations.
1279 It accepts the following parameters:
1281 @item channel_layout
1282 The channel layout of the output stream.
1285 Map channels from input to output. The argument is a '|'-separated list of
1286 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1287 @var{in_channel} form. @var{in_channel} can be either the name of the input
1288 channel (e.g. FL for front left) or its index in the input channel layout.
1289 @var{out_channel} is the name of the output channel or its index in the output
1290 channel layout. If @var{out_channel} is not given then it is implicitly an
1291 index, starting with zero and increasing by one for each mapping.
1294 If no mapping is present, the filter will implicitly map input channels to
1295 output channels, preserving indices.
1297 For example, assuming a 5.1+downmix input MOV file,
1299 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1301 will create an output WAV file tagged as stereo from the downmix channels of
1304 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1306 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1309 @section channelsplit
1311 Split each channel from an input audio stream into a separate output stream.
1313 It accepts the following parameters:
1315 @item channel_layout
1316 The channel layout of the input stream. The default is "stereo".
1319 For example, assuming a stereo input MP3 file,
1321 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1323 will create an output Matroska file with two audio streams, one containing only
1324 the left channel and the other the right channel.
1326 Split a 5.1 WAV file into per-channel files:
1328 ffmpeg -i in.wav -filter_complex
1329 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1330 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1331 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1336 Add a chorus effect to the audio.
1338 Can make a single vocal sound like a chorus, but can also be applied to instrumentation.
1340 Chorus resembles an echo effect with a short delay, but whereas with echo the delay is
1341 constant, with chorus, it is varied using using sinusoidal or triangular modulation.
1342 The modulation depth defines the range the modulated delay is played before or after
1343 the delay. Hence the delayed sound will sound slower or faster, that is the delayed
1344 sound tuned around the original one, like in a chorus where some vocals are slightly
1347 It accepts the following parameters:
1350 Set input gain. Default is 0.4.
1353 Set output gain. Default is 0.4.
1356 Set delays. A typical delay is around 40ms to 60ms.
1368 @subsection Examples
1374 chorus=0.7:0.9:55:0.4:0.25:2
1380 chorus=0.6:0.9:50|60:0.4|0.32:0.25|0.4:2|1.3
1384 Fuller sounding chorus with three delays:
1386 chorus=0.5:0.9:50|60|40:0.4|0.32|0.3:0.25|0.4|0.3:2|2.3|1.3
1391 Compress or expand the audio's dynamic range.
1393 It accepts the following parameters:
1399 A list of times in seconds for each channel over which the instantaneous level
1400 of the input signal is averaged to determine its volume. @var{attacks} refers to
1401 increase of volume and @var{decays} refers to decrease of volume. For most
1402 situations, the attack time (response to the audio getting louder) should be
1403 shorter than the decay time, because the human ear is more sensitive to sudden
1404 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1405 a typical value for decay is 0.8 seconds.
1408 A list of points for the transfer function, specified in dB relative to the
1409 maximum possible signal amplitude. Each key points list must be defined using
1410 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1411 @code{x0/y0 x1/y1 x2/y2 ....}
1413 The input values must be in strictly increasing order but the transfer function
1414 does not have to be monotonically rising. The point @code{0/0} is assumed but
1415 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1416 function are @code{-70/-70|-60/-20}.
1419 Set the curve radius in dB for all joints. It defaults to 0.01.
1422 Set the additional gain in dB to be applied at all points on the transfer
1423 function. This allows for easy adjustment of the overall gain.
1427 Set an initial volume, in dB, to be assumed for each channel when filtering
1428 starts. This permits the user to supply a nominal level initially, so that, for
1429 example, a very large gain is not applied to initial signal levels before the
1430 companding has begun to operate. A typical value for audio which is initially
1431 quiet is -90 dB. It defaults to 0.
1434 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1435 delayed before being fed to the volume adjuster. Specifying a delay
1436 approximately equal to the attack/decay times allows the filter to effectively
1437 operate in predictive rather than reactive mode. It defaults to 0.
1441 @subsection Examples
1445 Make music with both quiet and loud passages suitable for listening to in a
1448 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1451 Another example for audio with whisper and explosion parts:
1453 compand=0|0:1|1:-90/-900|-70/-70|-30/-9|0/-3:6:0:0:0
1457 A noise gate for when the noise is at a lower level than the signal:
1459 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1463 Here is another noise gate, this time for when the noise is at a higher level
1464 than the signal (making it, in some ways, similar to squelch):
1466 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1471 Apply a DC shift to the audio.
1473 This can be useful to remove a DC offset (caused perhaps by a hardware problem
1474 in the recording chain) from the audio. The effect of a DC offset is reduced
1475 headroom and hence volume. The @ref{astats} filter can be used to determine if
1476 a signal has a DC offset.
1480 Set the DC shift, allowed range is [-1, 1]. It indicates the amount to shift
1484 Optional. It should have a value much less than 1 (e.g. 0.05 or 0.02) and is
1485 used to prevent clipping.
1490 Make audio easier to listen to on headphones.
1492 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1493 so that when listened to on headphones the stereo image is moved from
1494 inside your head (standard for headphones) to outside and in front of
1495 the listener (standard for speakers).
1501 Apply a two-pole peaking equalisation (EQ) filter. With this
1502 filter, the signal-level at and around a selected frequency can
1503 be increased or decreased, whilst (unlike bandpass and bandreject
1504 filters) that at all other frequencies is unchanged.
1506 In order to produce complex equalisation curves, this filter can
1507 be given several times, each with a different central frequency.
1509 The filter accepts the following options:
1513 Set the filter's central frequency in Hz.
1516 Set method to specify band-width of filter.
1529 Specify the band-width of a filter in width_type units.
1532 Set the required gain or attenuation in dB.
1533 Beware of clipping when using a positive gain.
1536 @subsection Examples
1539 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1541 equalizer=f=1000:width_type=h:width=200:g=-10
1545 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1547 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1552 Apply a flanging effect to the audio.
1554 The filter accepts the following options:
1558 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
1561 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
1564 Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
1568 Set percentage of delayed signal mixed with original. Range from 0 to 100.
1569 Default value is 71.
1572 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
1575 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
1576 Default value is @var{sinusoidal}.
1579 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
1580 Default value is 25.
1583 Set delay-line interpolation, @var{linear} or @var{quadratic}.
1584 Default is @var{linear}.
1589 Apply a high-pass filter with 3dB point frequency.
1590 The filter can be either single-pole, or double-pole (the default).
1591 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1593 The filter accepts the following options:
1597 Set frequency in Hz. Default is 3000.
1600 Set number of poles. Default is 2.
1603 Set method to specify band-width of filter.
1616 Specify the band-width of a filter in width_type units.
1617 Applies only to double-pole filter.
1618 The default is 0.707q and gives a Butterworth response.
1623 Join multiple input streams into one multi-channel stream.
1625 It accepts the following parameters:
1629 The number of input streams. It defaults to 2.
1631 @item channel_layout
1632 The desired output channel layout. It defaults to stereo.
1635 Map channels from inputs to output. The argument is a '|'-separated list of
1636 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1637 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1638 can be either the name of the input channel (e.g. FL for front left) or its
1639 index in the specified input stream. @var{out_channel} is the name of the output
1643 The filter will attempt to guess the mappings when they are not specified
1644 explicitly. It does so by first trying to find an unused matching input channel
1645 and if that fails it picks the first unused input channel.
1647 Join 3 inputs (with properly set channel layouts):
1649 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1652 Build a 5.1 output from 6 single-channel streams:
1654 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1655 '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'
1661 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1663 To enable compilation of this filter you need to configure FFmpeg with
1664 @code{--enable-ladspa}.
1668 Specifies the name of LADSPA plugin library to load. If the environment
1669 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1670 each one of the directories specified by the colon separated list in
1671 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1672 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1673 @file{/usr/lib/ladspa/}.
1676 Specifies the plugin within the library. Some libraries contain only
1677 one plugin, but others contain many of them. If this is not set filter
1678 will list all available plugins within the specified library.
1681 Set the '|' separated list of controls which are zero or more floating point
1682 values that determine the behavior of the loaded plugin (for example delay,
1684 Controls need to be defined using the following syntax:
1685 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1686 @var{valuei} is the value set on the @var{i}-th control.
1687 If @option{controls} is set to @code{help}, all available controls and
1688 their valid ranges are printed.
1690 @item sample_rate, s
1691 Specify the sample rate, default to 44100. Only used if plugin have
1695 Set the number of samples per channel per each output frame, default
1696 is 1024. Only used if plugin have zero inputs.
1699 Set the minimum duration of the sourced audio. See
1700 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
1701 for the accepted syntax.
1702 Note that the resulting duration may be greater than the specified duration,
1703 as the generated audio is always cut at the end of a complete frame.
1704 If not specified, or the expressed duration is negative, the audio is
1705 supposed to be generated forever.
1706 Only used if plugin have zero inputs.
1710 @subsection Examples
1714 List all available plugins within amp (LADSPA example plugin) library:
1720 List all available controls and their valid ranges for @code{vcf_notch}
1721 plugin from @code{VCF} library:
1723 ladspa=f=vcf:p=vcf_notch:c=help
1727 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1730 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1734 Add reverberation to the audio using TAP-plugins
1735 (Tom's Audio Processing plugins):
1737 ladspa=file=tap_reverb:tap_reverb
1741 Generate white noise, with 0.2 amplitude:
1743 ladspa=file=cmt:noise_source_white:c=c0=.2
1747 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1748 @code{C* Audio Plugin Suite} (CAPS) library:
1750 ladspa=file=caps:Click:c=c1=20'
1754 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1756 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1760 @subsection Commands
1762 This filter supports the following commands:
1765 Modify the @var{N}-th control value.
1767 If the specified value is not valid, it is ignored and prior one is kept.
1772 Apply a low-pass filter with 3dB point frequency.
1773 The filter can be either single-pole or double-pole (the default).
1774 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1776 The filter accepts the following options:
1780 Set frequency in Hz. Default is 500.
1783 Set number of poles. Default is 2.
1786 Set method to specify band-width of filter.
1799 Specify the band-width of a filter in width_type units.
1800 Applies only to double-pole filter.
1801 The default is 0.707q and gives a Butterworth response.
1806 Mix channels with specific gain levels. The filter accepts the output
1807 channel layout followed by a set of channels definitions.
1809 This filter is also designed to efficiently remap the channels of an audio
1812 The filter accepts parameters of the form:
1813 "@var{l}|@var{outdef}|@var{outdef}|..."
1817 output channel layout or number of channels
1820 output channel specification, of the form:
1821 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1824 output channel to define, either a channel name (FL, FR, etc.) or a channel
1825 number (c0, c1, etc.)
1828 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1831 input channel to use, see out_name for details; it is not possible to mix
1832 named and numbered input channels
1835 If the `=' in a channel specification is replaced by `<', then the gains for
1836 that specification will be renormalized so that the total is 1, thus
1837 avoiding clipping noise.
1839 @subsection Mixing examples
1841 For example, if you want to down-mix from stereo to mono, but with a bigger
1842 factor for the left channel:
1844 pan=1c|c0=0.9*c0+0.1*c1
1847 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1848 7-channels surround:
1850 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1853 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1854 that should be preferred (see "-ac" option) unless you have very specific
1857 @subsection Remapping examples
1859 The channel remapping will be effective if, and only if:
1862 @item gain coefficients are zeroes or ones,
1863 @item only one input per channel output,
1866 If all these conditions are satisfied, the filter will notify the user ("Pure
1867 channel mapping detected"), and use an optimized and lossless method to do the
1870 For example, if you have a 5.1 source and want a stereo audio stream by
1871 dropping the extra channels:
1873 pan="stereo| c0=FL | c1=FR"
1876 Given the same source, you can also switch front left and front right channels
1877 and keep the input channel layout:
1879 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
1882 If the input is a stereo audio stream, you can mute the front left channel (and
1883 still keep the stereo channel layout) with:
1888 Still with a stereo audio stream input, you can copy the right channel in both
1889 front left and right:
1891 pan="stereo| c0=FR | c1=FR"
1896 ReplayGain scanner filter. This filter takes an audio stream as an input and
1897 outputs it unchanged.
1898 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1902 Convert the audio sample format, sample rate and channel layout. It is
1903 not meant to be used directly.
1905 @section silencedetect
1907 Detect silence in an audio stream.
1909 This filter logs a message when it detects that the input audio volume is less
1910 or equal to a noise tolerance value for a duration greater or equal to the
1911 minimum detected noise duration.
1913 The printed times and duration are expressed in seconds.
1915 The filter accepts the following options:
1919 Set silence duration until notification (default is 2 seconds).
1922 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1923 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1926 @subsection Examples
1930 Detect 5 seconds of silence with -50dB noise tolerance:
1932 silencedetect=n=-50dB:d=5
1936 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1937 tolerance in @file{silence.mp3}:
1939 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1943 @section silenceremove
1945 Remove silence from the beginning, middle or end of the audio.
1947 The filter accepts the following options:
1951 This value is used to indicate if audio should be trimmed at beginning of
1952 the audio. A value of zero indicates no silence should be trimmed from the
1953 beginning. When specifying a non-zero value, it trims audio up until it
1954 finds non-silence. Normally, when trimming silence from beginning of audio
1955 the @var{start_periods} will be @code{1} but it can be increased to higher
1956 values to trim all audio up to specific count of non-silence periods.
1957 Default value is @code{0}.
1959 @item start_duration
1960 Specify the amount of time that non-silence must be detected before it stops
1961 trimming audio. By increasing the duration, bursts of noises can be treated
1962 as silence and trimmed off. Default value is @code{0}.
1964 @item start_threshold
1965 This indicates what sample value should be treated as silence. For digital
1966 audio, a value of @code{0} may be fine but for audio recorded from analog,
1967 you may wish to increase the value to account for background noise.
1968 Can be specified in dB (in case "dB" is appended to the specified value)
1969 or amplitude ratio. Default value is @code{0}.
1972 Set the count for trimming silence from the end of audio.
1973 To remove silence from the middle of a file, specify a @var{stop_periods}
1974 that is negative. This value is then treated as a positive value and is
1975 used to indicate the effect should restart processing as specified by
1976 @var{start_periods}, making it suitable for removing periods of silence
1977 in the middle of the audio.
1978 Default value is @code{0}.
1981 Specify a duration of silence that must exist before audio is not copied any
1982 more. By specifying a higher duration, silence that is wanted can be left in
1984 Default value is @code{0}.
1986 @item stop_threshold
1987 This is the same as @option{start_threshold} but for trimming silence from
1989 Can be specified in dB (in case "dB" is appended to the specified value)
1990 or amplitude ratio. Default value is @code{0}.
1993 This indicate that @var{stop_duration} length of audio should be left intact
1994 at the beginning of each period of silence.
1995 For example, if you want to remove long pauses between words but do not want
1996 to remove the pauses completely. Default value is @code{0}.
2000 @subsection Examples
2004 The following example shows how this filter can be used to start a recording
2005 that does not contain the delay at the start which usually occurs between
2006 pressing the record button and the start of the performance:
2008 silenceremove=1:5:0.02
2014 Boost or cut treble (upper) frequencies of the audio using a two-pole
2015 shelving filter with a response similar to that of a standard
2016 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
2018 The filter accepts the following options:
2022 Give the gain at whichever is the lower of ~22 kHz and the
2023 Nyquist frequency. Its useful range is about -20 (for a large cut)
2024 to +20 (for a large boost). Beware of clipping when using a positive gain.
2027 Set the filter's central frequency and so can be used
2028 to extend or reduce the frequency range to be boosted or cut.
2029 The default value is @code{3000} Hz.
2032 Set method to specify band-width of filter.
2045 Determine how steep is the filter's shelf transition.
2050 Adjust the input audio volume.
2052 It accepts the following parameters:
2056 Set audio volume expression.
2058 Output values are clipped to the maximum value.
2060 The output audio volume is given by the relation:
2062 @var{output_volume} = @var{volume} * @var{input_volume}
2065 The default value for @var{volume} is "1.0".
2068 This parameter represents the mathematical precision.
2070 It determines which input sample formats will be allowed, which affects the
2071 precision of the volume scaling.
2075 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
2077 32-bit floating-point; this limits input sample format to FLT. (default)
2079 64-bit floating-point; this limits input sample format to DBL.
2083 Choose the behaviour on encountering ReplayGain side data in input frames.
2087 Remove ReplayGain side data, ignoring its contents (the default).
2090 Ignore ReplayGain side data, but leave it in the frame.
2093 Prefer the track gain, if present.
2096 Prefer the album gain, if present.
2099 @item replaygain_preamp
2100 Pre-amplification gain in dB to apply to the selected replaygain gain.
2102 Default value for @var{replaygain_preamp} is 0.0.
2105 Set when the volume expression is evaluated.
2107 It accepts the following values:
2110 only evaluate expression once during the filter initialization, or
2111 when the @samp{volume} command is sent
2114 evaluate expression for each incoming frame
2117 Default value is @samp{once}.
2120 The volume expression can contain the following parameters.
2124 frame number (starting at zero)
2127 @item nb_consumed_samples
2128 number of samples consumed by the filter
2130 number of samples in the current frame
2132 original frame position in the file
2138 PTS at start of stream
2140 time at start of stream
2146 last set volume value
2149 Note that when @option{eval} is set to @samp{once} only the
2150 @var{sample_rate} and @var{tb} variables are available, all other
2151 variables will evaluate to NAN.
2153 @subsection Commands
2155 This filter supports the following commands:
2158 Modify the volume expression.
2159 The command accepts the same syntax of the corresponding option.
2161 If the specified expression is not valid, it is kept at its current
2163 @item replaygain_noclip
2164 Prevent clipping by limiting the gain applied.
2166 Default value for @var{replaygain_noclip} is 1.
2170 @subsection Examples
2174 Halve the input audio volume:
2178 volume=volume=-6.0206dB
2181 In all the above example the named key for @option{volume} can be
2182 omitted, for example like in:
2188 Increase input audio power by 6 decibels using fixed-point precision:
2190 volume=volume=6dB:precision=fixed
2194 Fade volume after time 10 with an annihilation period of 5 seconds:
2196 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
2200 @section volumedetect
2202 Detect the volume of the input video.
2204 The filter has no parameters. The input is not modified. Statistics about
2205 the volume will be printed in the log when the input stream end is reached.
2207 In particular it will show the mean volume (root mean square), maximum
2208 volume (on a per-sample basis), and the beginning of a histogram of the
2209 registered volume values (from the maximum value to a cumulated 1/1000 of
2212 All volumes are in decibels relative to the maximum PCM value.
2214 @subsection Examples
2216 Here is an excerpt of the output:
2218 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2219 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2220 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2221 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2222 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2223 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2224 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2225 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2226 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2232 The mean square energy is approximately -27 dB, or 10^-2.7.
2234 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2236 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2239 In other words, raising the volume by +4 dB does not cause any clipping,
2240 raising it by +5 dB causes clipping for 6 samples, etc.
2242 @c man end AUDIO FILTERS
2244 @chapter Audio Sources
2245 @c man begin AUDIO SOURCES
2247 Below is a description of the currently available audio sources.
2251 Buffer audio frames, and make them available to the filter chain.
2253 This source is mainly intended for a programmatic use, in particular
2254 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2256 It accepts the following parameters:
2260 The timebase which will be used for timestamps of submitted frames. It must be
2261 either a floating-point number or in @var{numerator}/@var{denominator} form.
2264 The sample rate of the incoming audio buffers.
2267 The sample format of the incoming audio buffers.
2268 Either a sample format name or its corresponding integer representation from
2269 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2271 @item channel_layout
2272 The channel layout of the incoming audio buffers.
2273 Either a channel layout name from channel_layout_map in
2274 @file{libavutil/channel_layout.c} or its corresponding integer representation
2275 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2278 The number of channels of the incoming audio buffers.
2279 If both @var{channels} and @var{channel_layout} are specified, then they
2284 @subsection Examples
2287 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2290 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2291 Since the sample format with name "s16p" corresponds to the number
2292 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2295 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2300 Generate an audio signal specified by an expression.
2302 This source accepts in input one or more expressions (one for each
2303 channel), which are evaluated and used to generate a corresponding
2306 This source accepts the following options:
2310 Set the '|'-separated expressions list for each separate channel. In case the
2311 @option{channel_layout} option is not specified, the selected channel layout
2312 depends on the number of provided expressions. Otherwise the last
2313 specified expression is applied to the remaining output channels.
2315 @item channel_layout, c
2316 Set the channel layout. The number of channels in the specified layout
2317 must be equal to the number of specified expressions.
2320 Set the minimum duration of the sourced audio. See
2321 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2322 for the accepted syntax.
2323 Note that the resulting duration may be greater than the specified
2324 duration, as the generated audio is always cut at the end of a
2327 If not specified, or the expressed duration is negative, the audio is
2328 supposed to be generated forever.
2331 Set the number of samples per channel per each output frame,
2334 @item sample_rate, s
2335 Specify the sample rate, default to 44100.
2338 Each expression in @var{exprs} can contain the following constants:
2342 number of the evaluated sample, starting from 0
2345 time of the evaluated sample expressed in seconds, starting from 0
2352 @subsection Examples
2362 Generate a sin signal with frequency of 440 Hz, set sample rate to
2365 aevalsrc="sin(440*2*PI*t):s=8000"
2369 Generate a two channels signal, specify the channel layout (Front
2370 Center + Back Center) explicitly:
2372 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2376 Generate white noise:
2378 aevalsrc="-2+random(0)"
2382 Generate an amplitude modulated signal:
2384 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2388 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2390 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2397 The null audio source, return unprocessed audio frames. It is mainly useful
2398 as a template and to be employed in analysis / debugging tools, or as
2399 the source for filters which ignore the input data (for example the sox
2402 This source accepts the following options:
2406 @item channel_layout, cl
2408 Specifies the channel layout, and can be either an integer or a string
2409 representing a channel layout. The default value of @var{channel_layout}
2412 Check the channel_layout_map definition in
2413 @file{libavutil/channel_layout.c} for the mapping between strings and
2414 channel layout values.
2416 @item sample_rate, r
2417 Specifies the sample rate, and defaults to 44100.
2420 Set the number of samples per requested frames.
2424 @subsection Examples
2428 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2430 anullsrc=r=48000:cl=4
2434 Do the same operation with a more obvious syntax:
2436 anullsrc=r=48000:cl=mono
2440 All the parameters need to be explicitly defined.
2444 Synthesize a voice utterance using the libflite library.
2446 To enable compilation of this filter you need to configure FFmpeg with
2447 @code{--enable-libflite}.
2449 Note that the flite library is not thread-safe.
2451 The filter accepts the following options:
2456 If set to 1, list the names of the available voices and exit
2457 immediately. Default value is 0.
2460 Set the maximum number of samples per frame. Default value is 512.
2463 Set the filename containing the text to speak.
2466 Set the text to speak.
2469 Set the voice to use for the speech synthesis. Default value is
2470 @code{kal}. See also the @var{list_voices} option.
2473 @subsection Examples
2477 Read from file @file{speech.txt}, and synthesize the text using the
2478 standard flite voice:
2480 flite=textfile=speech.txt
2484 Read the specified text selecting the @code{slt} voice:
2486 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2490 Input text to ffmpeg:
2492 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2496 Make @file{ffplay} speak the specified text, using @code{flite} and
2497 the @code{lavfi} device:
2499 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2503 For more information about libflite, check:
2504 @url{http://www.speech.cs.cmu.edu/flite/}
2508 Generate an audio signal made of a sine wave with amplitude 1/8.
2510 The audio signal is bit-exact.
2512 The filter accepts the following options:
2517 Set the carrier frequency. Default is 440 Hz.
2519 @item beep_factor, b
2520 Enable a periodic beep every second with frequency @var{beep_factor} times
2521 the carrier frequency. Default is 0, meaning the beep is disabled.
2523 @item sample_rate, r
2524 Specify the sample rate, default is 44100.
2527 Specify the duration of the generated audio stream.
2529 @item samples_per_frame
2530 Set the number of samples per output frame, default is 1024.
2533 @subsection Examples
2538 Generate a simple 440 Hz sine wave:
2544 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2548 sine=frequency=220:beep_factor=4:duration=5
2553 @c man end AUDIO SOURCES
2555 @chapter Audio Sinks
2556 @c man begin AUDIO SINKS
2558 Below is a description of the currently available audio sinks.
2560 @section abuffersink
2562 Buffer audio frames, and make them available to the end of filter chain.
2564 This sink is mainly intended for programmatic use, in particular
2565 through the interface defined in @file{libavfilter/buffersink.h}
2566 or the options system.
2568 It accepts a pointer to an AVABufferSinkContext structure, which
2569 defines the incoming buffers' formats, to be passed as the opaque
2570 parameter to @code{avfilter_init_filter} for initialization.
2573 Null audio sink; do absolutely nothing with the input audio. It is
2574 mainly useful as a template and for use in analysis / debugging
2577 @c man end AUDIO SINKS
2579 @chapter Video Filters
2580 @c man begin VIDEO FILTERS
2582 When you configure your FFmpeg build, you can disable any of the
2583 existing filters using @code{--disable-filters}.
2584 The configure output will show the video filters included in your
2587 Below is a description of the currently available video filters.
2589 @section alphaextract
2591 Extract the alpha component from the input as a grayscale video. This
2592 is especially useful with the @var{alphamerge} filter.
2596 Add or replace the alpha component of the primary input with the
2597 grayscale value of a second input. This is intended for use with
2598 @var{alphaextract} to allow the transmission or storage of frame
2599 sequences that have alpha in a format that doesn't support an alpha
2602 For example, to reconstruct full frames from a normal YUV-encoded video
2603 and a separate video created with @var{alphaextract}, you might use:
2605 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2608 Since this filter is designed for reconstruction, it operates on frame
2609 sequences without considering timestamps, and terminates when either
2610 input reaches end of stream. This will cause problems if your encoding
2611 pipeline drops frames. If you're trying to apply an image as an
2612 overlay to a video stream, consider the @var{overlay} filter instead.
2616 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2617 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2618 Substation Alpha) subtitles files.
2620 This filter accepts the following option in addition to the common options from
2621 the @ref{subtitles} filter:
2625 Set the shaping engine
2627 Available values are:
2630 The default libass shaping engine, which is the best available.
2632 Fast, font-agnostic shaper that can do only substitutions
2634 Slower shaper using OpenType for substitutions and positioning
2637 The default is @code{auto}.
2642 Compute the bounding box for the non-black pixels in the input frame
2645 This filter computes the bounding box containing all the pixels with a
2646 luminance value greater than the minimum allowed value.
2647 The parameters describing the bounding box are printed on the filter
2650 The filter accepts the following option:
2654 Set the minimal luminance value. Default is @code{16}.
2657 @section blackdetect
2659 Detect video intervals that are (almost) completely black. Can be
2660 useful to detect chapter transitions, commercials, or invalid
2661 recordings. Output lines contains the time for the start, end and
2662 duration of the detected black interval expressed in seconds.
2664 In order to display the output lines, you need to set the loglevel at
2665 least to the AV_LOG_INFO value.
2667 The filter accepts the following options:
2670 @item black_min_duration, d
2671 Set the minimum detected black duration expressed in seconds. It must
2672 be a non-negative floating point number.
2674 Default value is 2.0.
2676 @item picture_black_ratio_th, pic_th
2677 Set the threshold for considering a picture "black".
2678 Express the minimum value for the ratio:
2680 @var{nb_black_pixels} / @var{nb_pixels}
2683 for which a picture is considered black.
2684 Default value is 0.98.
2686 @item pixel_black_th, pix_th
2687 Set the threshold for considering a pixel "black".
2689 The threshold expresses the maximum pixel luminance value for which a
2690 pixel is considered "black". The provided value is scaled according to
2691 the following equation:
2693 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2696 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2697 the input video format, the range is [0-255] for YUV full-range
2698 formats and [16-235] for YUV non full-range formats.
2700 Default value is 0.10.
2703 The following example sets the maximum pixel threshold to the minimum
2704 value, and detects only black intervals of 2 or more seconds:
2706 blackdetect=d=2:pix_th=0.00
2711 Detect frames that are (almost) completely black. Can be useful to
2712 detect chapter transitions or commercials. Output lines consist of
2713 the frame number of the detected frame, the percentage of blackness,
2714 the position in the file if known or -1 and the timestamp in seconds.
2716 In order to display the output lines, you need to set the loglevel at
2717 least to the AV_LOG_INFO value.
2719 It accepts the following parameters:
2724 The percentage of the pixels that have to be below the threshold; it defaults to
2727 @item threshold, thresh
2728 The threshold below which a pixel value is considered black; it defaults to
2733 @section blend, tblend
2735 Blend two video frames into each other.
2737 The @code{blend} filter takes two input streams and outputs one
2738 stream, the first input is the "top" layer and second input is
2739 "bottom" layer. Output terminates when shortest input terminates.
2741 The @code{tblend} (time blend) filter takes two consecutive frames
2742 from one single stream, and outputs the result obtained by blending
2743 the new frame on top of the old frame.
2745 A description of the accepted options follows.
2753 Set blend mode for specific pixel component or all pixel components in case
2754 of @var{all_mode}. Default value is @code{normal}.
2756 Available values for component modes are:
2793 Set blend opacity for specific pixel component or all pixel components in case
2794 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2801 Set blend expression for specific pixel component or all pixel components in case
2802 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2804 The expressions can use the following variables:
2808 The sequential number of the filtered frame, starting from @code{0}.
2812 the coordinates of the current sample
2816 the width and height of currently filtered plane
2820 Width and height scale depending on the currently filtered plane. It is the
2821 ratio between the corresponding luma plane number of pixels and the current
2822 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2823 @code{0.5,0.5} for chroma planes.
2826 Time of the current frame, expressed in seconds.
2829 Value of pixel component at current location for first video frame (top layer).
2832 Value of pixel component at current location for second video frame (bottom layer).
2836 Force termination when the shortest input terminates. Default is
2837 @code{0}. This option is only defined for the @code{blend} filter.
2840 Continue applying the last bottom frame after the end of the stream. A value of
2841 @code{0} disable the filter after the last frame of the bottom layer is reached.
2842 Default is @code{1}. This option is only defined for the @code{blend} filter.
2845 @subsection Examples
2849 Apply transition from bottom layer to top layer in first 10 seconds:
2851 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2855 Apply 1x1 checkerboard effect:
2857 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2861 Apply uncover left effect:
2863 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2867 Apply uncover down effect:
2869 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2873 Apply uncover up-left effect:
2875 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2879 Display differences between the current and the previous frame:
2881 tblend=all_mode=difference128
2887 Apply a boxblur algorithm to the input video.
2889 It accepts the following parameters:
2893 @item luma_radius, lr
2894 @item luma_power, lp
2895 @item chroma_radius, cr
2896 @item chroma_power, cp
2897 @item alpha_radius, ar
2898 @item alpha_power, ap
2902 A description of the accepted options follows.
2905 @item luma_radius, lr
2906 @item chroma_radius, cr
2907 @item alpha_radius, ar
2908 Set an expression for the box radius in pixels used for blurring the
2909 corresponding input plane.
2911 The radius value must be a non-negative number, and must not be
2912 greater than the value of the expression @code{min(w,h)/2} for the
2913 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2916 Default value for @option{luma_radius} is "2". If not specified,
2917 @option{chroma_radius} and @option{alpha_radius} default to the
2918 corresponding value set for @option{luma_radius}.
2920 The expressions can contain the following constants:
2924 The input width and height in pixels.
2928 The input chroma image width and height in pixels.
2932 The horizontal and vertical chroma subsample values. For example, for the
2933 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
2936 @item luma_power, lp
2937 @item chroma_power, cp
2938 @item alpha_power, ap
2939 Specify how many times the boxblur filter is applied to the
2940 corresponding plane.
2942 Default value for @option{luma_power} is 2. If not specified,
2943 @option{chroma_power} and @option{alpha_power} default to the
2944 corresponding value set for @option{luma_power}.
2946 A value of 0 will disable the effect.
2949 @subsection Examples
2953 Apply a boxblur filter with the luma, chroma, and alpha radii
2956 boxblur=luma_radius=2:luma_power=1
2961 Set the luma radius to 2, and alpha and chroma radius to 0:
2963 boxblur=2:1:cr=0:ar=0
2967 Set the luma and chroma radii to a fraction of the video dimension:
2969 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2975 Visualize information exported by some codecs.
2977 Some codecs can export information through frames using side-data or other
2978 means. For example, some MPEG based codecs export motion vectors through the
2979 @var{export_mvs} flag in the codec @option{flags2} option.
2981 The filter accepts the following option:
2985 Set motion vectors to visualize.
2987 Available flags for @var{mv} are:
2991 forward predicted MVs of P-frames
2993 forward predicted MVs of B-frames
2995 backward predicted MVs of B-frames
2999 @subsection Examples
3003 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
3005 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
3009 @section colorbalance
3010 Modify intensity of primary colors (red, green and blue) of input frames.
3012 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
3013 regions for the red-cyan, green-magenta or blue-yellow balance.
3015 A positive adjustment value shifts the balance towards the primary color, a negative
3016 value towards the complementary color.
3018 The filter accepts the following options:
3024 Adjust red, green and blue shadows (darkest pixels).
3029 Adjust red, green and blue midtones (medium pixels).
3034 Adjust red, green and blue highlights (brightest pixels).
3036 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
3039 @subsection Examples
3043 Add red color cast to shadows:
3050 RGB colorspace color keying.
3052 The filter accepts the following options:
3056 The color which will be replaced with transparency.
3059 Similarity percentage with the key color.
3061 0.01 matches only the exact key color, while 1.0 matches everything.
3066 0.0 makes pixels either fully transparent, or not transparent at all.
3068 Higher values result in semi-transparent pixels, with a higher transparency
3069 the more similar the pixels color is to the key color.
3072 @subsection Examples
3076 Make every green pixel in the input image transparent:
3078 ffmpeg -i input.png -vf colorkey=green out.png
3082 Overlay a greenscreen-video on top of a static background image.
3084 ffmpeg -i background.png -i video.mp4 -filter_complex "[1:v]colorkey=0x3BBD1E:0.3:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.flv
3088 @section colorlevels
3090 Adjust video input frames using levels.
3092 The filter accepts the following options:
3099 Adjust red, green, blue and alpha input black point.
3100 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
3106 Adjust red, green, blue and alpha input white point.
3107 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
3109 Input levels are used to lighten highlights (bright tones), darken shadows
3110 (dark tones), change the balance of bright and dark tones.
3116 Adjust red, green, blue and alpha output black point.
3117 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
3123 Adjust red, green, blue and alpha output white point.
3124 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
3126 Output levels allows manual selection of a constrained output level range.
3129 @subsection Examples
3133 Make video output darker:
3135 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
3141 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
3145 Make video output lighter:
3147 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
3151 Increase brightness:
3153 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
3157 @section colorchannelmixer
3159 Adjust video input frames by re-mixing color channels.
3161 This filter modifies a color channel by adding the values associated to
3162 the other channels of the same pixels. For example if the value to
3163 modify is red, the output value will be:
3165 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
3168 The filter accepts the following options:
3175 Adjust contribution of input red, green, blue and alpha channels for output red channel.
3176 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
3182 Adjust contribution of input red, green, blue and alpha channels for output green channel.
3183 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
3189 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
3190 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
3196 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
3197 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
3199 Allowed ranges for options are @code{[-2.0, 2.0]}.
3202 @subsection Examples
3206 Convert source to grayscale:
3208 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
3211 Simulate sepia tones:
3213 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
3217 @section colormatrix
3219 Convert color matrix.
3221 The filter accepts the following options:
3226 Specify the source and destination color matrix. Both values must be
3229 The accepted values are:
3245 For example to convert from BT.601 to SMPTE-240M, use the command:
3247 colormatrix=bt601:smpte240m
3252 Copy the input source unchanged to the output. This is mainly useful for
3257 Crop the input video to given dimensions.
3259 It accepts the following parameters:
3263 The width of the output video. It defaults to @code{iw}.
3264 This expression is evaluated only once during the filter
3268 The height of the output video. It defaults to @code{ih}.
3269 This expression is evaluated only once during the filter
3273 The horizontal position, in the input video, of the left edge of the output
3274 video. It defaults to @code{(in_w-out_w)/2}.
3275 This expression is evaluated per-frame.
3278 The vertical position, in the input video, of the top edge of the output video.
3279 It defaults to @code{(in_h-out_h)/2}.
3280 This expression is evaluated per-frame.
3283 If set to 1 will force the output display aspect ratio
3284 to be the same of the input, by changing the output sample aspect
3285 ratio. It defaults to 0.
3288 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
3289 expressions containing the following constants:
3294 The computed values for @var{x} and @var{y}. They are evaluated for
3299 The input width and height.
3303 These are the same as @var{in_w} and @var{in_h}.
3307 The output (cropped) width and height.
3311 These are the same as @var{out_w} and @var{out_h}.
3314 same as @var{iw} / @var{ih}
3317 input sample aspect ratio
3320 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
3324 horizontal and vertical chroma subsample values. For example for the
3325 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3328 The number of the input frame, starting from 0.
3331 the position in the file of the input frame, NAN if unknown
3334 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
3338 The expression for @var{out_w} may depend on the value of @var{out_h},
3339 and the expression for @var{out_h} may depend on @var{out_w}, but they
3340 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
3341 evaluated after @var{out_w} and @var{out_h}.
3343 The @var{x} and @var{y} parameters specify the expressions for the
3344 position of the top-left corner of the output (non-cropped) area. They
3345 are evaluated for each frame. If the evaluated value is not valid, it
3346 is approximated to the nearest valid value.
3348 The expression for @var{x} may depend on @var{y}, and the expression
3349 for @var{y} may depend on @var{x}.
3351 @subsection Examples
3355 Crop area with size 100x100 at position (12,34).
3360 Using named options, the example above becomes:
3362 crop=w=100:h=100:x=12:y=34
3366 Crop the central input area with size 100x100:
3372 Crop the central input area with size 2/3 of the input video:
3374 crop=2/3*in_w:2/3*in_h
3378 Crop the input video central square:
3385 Delimit the rectangle with the top-left corner placed at position
3386 100:100 and the right-bottom corner corresponding to the right-bottom
3387 corner of the input image.
3389 crop=in_w-100:in_h-100:100:100
3393 Crop 10 pixels from the left and right borders, and 20 pixels from
3394 the top and bottom borders
3396 crop=in_w-2*10:in_h-2*20
3400 Keep only the bottom right quarter of the input image:
3402 crop=in_w/2:in_h/2:in_w/2:in_h/2
3406 Crop height for getting Greek harmony:
3408 crop=in_w:1/PHI*in_w
3412 Apply trembling effect:
3414 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)
3418 Apply erratic camera effect depending on timestamp:
3420 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)"
3424 Set x depending on the value of y:
3426 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3432 Auto-detect the crop size.
3434 It calculates the necessary cropping parameters and prints the
3435 recommended parameters via the logging system. The detected dimensions
3436 correspond to the non-black area of the input video.
3438 It accepts the following parameters:
3443 Set higher black value threshold, which can be optionally specified
3444 from nothing (0) to everything (255 for 8bit based formats). An intensity
3445 value greater to the set value is considered non-black. It defaults to 24.
3446 You can also specify a value between 0.0 and 1.0 which will be scaled depending
3447 on the bitdepth of the pixel format.
3450 The value which the width/height should be divisible by. It defaults to
3451 16. The offset is automatically adjusted to center the video. Use 2 to
3452 get only even dimensions (needed for 4:2:2 video). 16 is best when
3453 encoding to most video codecs.
3455 @item reset_count, reset
3456 Set the counter that determines after how many frames cropdetect will
3457 reset the previously detected largest video area and start over to
3458 detect the current optimal crop area. Default value is 0.
3460 This can be useful when channel logos distort the video area. 0
3461 indicates 'never reset', and returns the largest area encountered during
3468 Apply color adjustments using curves.
3470 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3471 component (red, green and blue) has its values defined by @var{N} key points
3472 tied from each other using a smooth curve. The x-axis represents the pixel
3473 values from the input frame, and the y-axis the new pixel values to be set for
3476 By default, a component curve is defined by the two points @var{(0;0)} and
3477 @var{(1;1)}. This creates a straight line where each original pixel value is
3478 "adjusted" to its own value, which means no change to the image.
3480 The filter allows you to redefine these two points and add some more. A new
3481 curve (using a natural cubic spline interpolation) will be define to pass
3482 smoothly through all these new coordinates. The new defined points needs to be
3483 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3484 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3485 the vector spaces, the values will be clipped accordingly.
3487 If there is no key point defined in @code{x=0}, the filter will automatically
3488 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3489 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3491 The filter accepts the following options:
3495 Select one of the available color presets. This option can be used in addition
3496 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3497 options takes priority on the preset values.
3498 Available presets are:
3501 @item color_negative
3504 @item increase_contrast
3506 @item linear_contrast
3507 @item medium_contrast
3509 @item strong_contrast
3512 Default is @code{none}.
3514 Set the master key points. These points will define a second pass mapping. It
3515 is sometimes called a "luminance" or "value" mapping. It can be used with
3516 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3517 post-processing LUT.
3519 Set the key points for the red component.
3521 Set the key points for the green component.
3523 Set the key points for the blue component.
3525 Set the key points for all components (not including master).
3526 Can be used in addition to the other key points component
3527 options. In this case, the unset component(s) will fallback on this
3528 @option{all} setting.
3530 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3533 To avoid some filtergraph syntax conflicts, each key points list need to be
3534 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3536 @subsection Examples
3540 Increase slightly the middle level of blue:
3542 curves=blue='0.5/0.58'
3548 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3550 Here we obtain the following coordinates for each components:
3553 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3555 @code{(0;0) (0.50;0.48) (1;1)}
3557 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3561 The previous example can also be achieved with the associated built-in preset:
3563 curves=preset=vintage
3573 Use a Photoshop preset and redefine the points of the green component:
3575 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3581 Denoise frames using 2D DCT (frequency domain filtering).
3583 This filter is not designed for real time.
3585 The filter accepts the following options:
3589 Set the noise sigma constant.
3591 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3592 coefficient (absolute value) below this threshold with be dropped.
3594 If you need a more advanced filtering, see @option{expr}.
3596 Default is @code{0}.
3599 Set number overlapping pixels for each block. Since the filter can be slow, you
3600 may want to reduce this value, at the cost of a less effective filter and the
3601 risk of various artefacts.
3603 If the overlapping value doesn't permit processing the whole input width or
3604 height, a warning will be displayed and according borders won't be denoised.
3606 Default value is @var{blocksize}-1, which is the best possible setting.
3609 Set the coefficient factor expression.
3611 For each coefficient of a DCT block, this expression will be evaluated as a
3612 multiplier value for the coefficient.
3614 If this is option is set, the @option{sigma} option will be ignored.
3616 The absolute value of the coefficient can be accessed through the @var{c}
3620 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
3621 @var{blocksize}, which is the width and height of the processed blocks.
3623 The default value is @var{3} (8x8) and can be raised to @var{4} for a
3624 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
3625 on the speed processing. Also, a larger block size does not necessarily means a
3629 @subsection Examples
3631 Apply a denoise with a @option{sigma} of @code{4.5}:
3636 The same operation can be achieved using the expression system:
3638 dctdnoiz=e='gte(c, 4.5*3)'
3641 Violent denoise using a block size of @code{16x16}:
3649 Drop duplicated frames at regular intervals.
3651 The filter accepts the following options:
3655 Set the number of frames from which one will be dropped. Setting this to
3656 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3657 Default is @code{5}.
3660 Set the threshold for duplicate detection. If the difference metric for a frame
3661 is less than or equal to this value, then it is declared as duplicate. Default
3665 Set scene change threshold. Default is @code{15}.
3669 Set the size of the x and y-axis blocks used during metric calculations.
3670 Larger blocks give better noise suppression, but also give worse detection of
3671 small movements. Must be a power of two. Default is @code{32}.
3674 Mark main input as a pre-processed input and activate clean source input
3675 stream. This allows the input to be pre-processed with various filters to help
3676 the metrics calculation while keeping the frame selection lossless. When set to
3677 @code{1}, the first stream is for the pre-processed input, and the second
3678 stream is the clean source from where the kept frames are chosen. Default is
3682 Set whether or not chroma is considered in the metric calculations. Default is
3688 Remove judder produced by partially interlaced telecined content.
3690 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3691 source was partially telecined content then the output of @code{pullup,dejudder}
3692 will have a variable frame rate. May change the recorded frame rate of the
3693 container. Aside from that change, this filter will not affect constant frame
3696 The option available in this filter is:
3700 Specify the length of the window over which the judder repeats.
3702 Accepts any integer greater than 1. Useful values are:
3706 If the original was telecined from 24 to 30 fps (Film to NTSC).
3709 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3712 If a mixture of the two.
3715 The default is @samp{4}.
3720 Suppress a TV station logo by a simple interpolation of the surrounding
3721 pixels. Just set a rectangle covering the logo and watch it disappear
3722 (and sometimes something even uglier appear - your mileage may vary).
3724 It accepts the following parameters:
3729 Specify the top left corner coordinates of the logo. They must be
3734 Specify the width and height of the logo to clear. They must be
3738 Specify the thickness of the fuzzy edge of the rectangle (added to
3739 @var{w} and @var{h}). The default value is 4.
3742 When set to 1, a green rectangle is drawn on the screen to simplify
3743 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3744 The default value is 0.
3746 The rectangle is drawn on the outermost pixels which will be (partly)
3747 replaced with interpolated values. The values of the next pixels
3748 immediately outside this rectangle in each direction will be used to
3749 compute the interpolated pixel values inside the rectangle.
3753 @subsection Examples
3757 Set a rectangle covering the area with top left corner coordinates 0,0
3758 and size 100x77, and a band of size 10:
3760 delogo=x=0:y=0:w=100:h=77:band=10
3767 Attempt to fix small changes in horizontal and/or vertical shift. This
3768 filter helps remove camera shake from hand-holding a camera, bumping a
3769 tripod, moving on a vehicle, etc.
3771 The filter accepts the following options:
3779 Specify a rectangular area where to limit the search for motion
3781 If desired the search for motion vectors can be limited to a
3782 rectangular area of the frame defined by its top left corner, width
3783 and height. These parameters have the same meaning as the drawbox
3784 filter which can be used to visualise the position of the bounding
3787 This is useful when simultaneous movement of subjects within the frame
3788 might be confused for camera motion by the motion vector search.
3790 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3791 then the full frame is used. This allows later options to be set
3792 without specifying the bounding box for the motion vector search.
3794 Default - search the whole frame.
3798 Specify the maximum extent of movement in x and y directions in the
3799 range 0-64 pixels. Default 16.
3802 Specify how to generate pixels to fill blanks at the edge of the
3803 frame. Available values are:
3806 Fill zeroes at blank locations
3808 Original image at blank locations
3810 Extruded edge value at blank locations
3812 Mirrored edge at blank locations
3814 Default value is @samp{mirror}.
3817 Specify the blocksize to use for motion search. Range 4-128 pixels,
3821 Specify the contrast threshold for blocks. Only blocks with more than
3822 the specified contrast (difference between darkest and lightest
3823 pixels) will be considered. Range 1-255, default 125.
3826 Specify the search strategy. Available values are:
3829 Set exhaustive search
3831 Set less exhaustive search.
3833 Default value is @samp{exhaustive}.
3836 If set then a detailed log of the motion search is written to the
3840 If set to 1, specify using OpenCL capabilities, only available if
3841 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3847 Apply an exact inverse of the telecine operation. It requires a predefined
3848 pattern specified using the pattern option which must be the same as that passed
3849 to the telecine filter.
3851 This filter accepts the following options:
3860 The default value is @code{top}.
3864 A string of numbers representing the pulldown pattern you wish to apply.
3865 The default value is @code{23}.
3868 A number representing position of the first frame with respect to the telecine
3869 pattern. This is to be used if the stream is cut. The default value is @code{0}.
3874 Draw a colored box on the input image.
3876 It accepts the following parameters:
3881 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3885 The expressions which specify the width and height of the box; if 0 they are interpreted as
3886 the input width and height. It defaults to 0.
3889 Specify the color of the box to write. For the general syntax of this option,
3890 check the "Color" section in the ffmpeg-utils manual. If the special
3891 value @code{invert} is used, the box edge color is the same as the
3892 video with inverted luma.
3895 The expression which sets the thickness of the box edge. Default value is @code{3}.
3897 See below for the list of accepted constants.
3900 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3901 following constants:
3905 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3909 horizontal and vertical chroma subsample values. For example for the
3910 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3914 The input width and height.
3917 The input sample aspect ratio.
3921 The x and y offset coordinates where the box is drawn.
3925 The width and height of the drawn box.
3928 The thickness of the drawn box.
3930 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3931 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3935 @subsection Examples
3939 Draw a black box around the edge of the input image:
3945 Draw a box with color red and an opacity of 50%:
3947 drawbox=10:20:200:60:red@@0.5
3950 The previous example can be specified as:
3952 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3956 Fill the box with pink color:
3958 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3962 Draw a 2-pixel red 2.40:1 mask:
3964 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
3970 Draw a grid on the input image.
3972 It accepts the following parameters:
3977 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3981 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3982 input width and height, respectively, minus @code{thickness}, so image gets
3983 framed. Default to 0.
3986 Specify the color of the grid. For the general syntax of this option,
3987 check the "Color" section in the ffmpeg-utils manual. If the special
3988 value @code{invert} is used, the grid color is the same as the
3989 video with inverted luma.
3992 The expression which sets the thickness of the grid line. Default value is @code{1}.
3994 See below for the list of accepted constants.
3997 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3998 following constants:
4002 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
4006 horizontal and vertical chroma subsample values. For example for the
4007 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4011 The input grid cell width and height.
4014 The input sample aspect ratio.
4018 The x and y coordinates of some point of grid intersection (meant to configure offset).
4022 The width and height of the drawn cell.
4025 The thickness of the drawn cell.
4027 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
4028 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
4032 @subsection Examples
4036 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
4038 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
4042 Draw a white 3x3 grid with an opacity of 50%:
4044 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
4051 Draw a text string or text from a specified file on top of a video, using the
4052 libfreetype library.
4054 To enable compilation of this filter, you need to configure FFmpeg with
4055 @code{--enable-libfreetype}.
4056 To enable default font fallback and the @var{font} option you need to
4057 configure FFmpeg with @code{--enable-libfontconfig}.
4058 To enable the @var{text_shaping} option, you need to configure FFmpeg with
4059 @code{--enable-libfribidi}.
4063 It accepts the following parameters:
4068 Used to draw a box around text using the background color.
4069 The value must be either 1 (enable) or 0 (disable).
4070 The default value of @var{box} is 0.
4073 Set the width of the border to be drawn around the box using @var{boxcolor}.
4074 The default value of @var{boxborderw} is 0.
4077 The color to be used for drawing box around text. For the syntax of this
4078 option, check the "Color" section in the ffmpeg-utils manual.
4080 The default value of @var{boxcolor} is "white".
4083 Set the width of the border to be drawn around the text using @var{bordercolor}.
4084 The default value of @var{borderw} is 0.
4087 Set the color to be used for drawing border around text. For the syntax of this
4088 option, check the "Color" section in the ffmpeg-utils manual.
4090 The default value of @var{bordercolor} is "black".
4093 Select how the @var{text} is expanded. Can be either @code{none},
4094 @code{strftime} (deprecated) or
4095 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
4099 If true, check and fix text coords to avoid clipping.
4102 The color to be used for drawing fonts. For the syntax of this option, check
4103 the "Color" section in the ffmpeg-utils manual.
4105 The default value of @var{fontcolor} is "black".
4107 @item fontcolor_expr
4108 String which is expanded the same way as @var{text} to obtain dynamic
4109 @var{fontcolor} value. By default this option has empty value and is not
4110 processed. When this option is set, it overrides @var{fontcolor} option.
4113 The font family to be used for drawing text. By default Sans.
4116 The font file to be used for drawing text. The path must be included.
4117 This parameter is mandatory if the fontconfig support is disabled.
4120 This option does not exist, please see the timeline system
4123 Draw the text applying alpha blending. The value can
4124 be either a number between 0.0 and 1.0
4125 The expression accepts the same variables @var{x, y} do.
4126 The default value is 1.
4127 Please see fontcolor_expr
4130 The font size to be used for drawing text.
4131 The default value of @var{fontsize} is 16.
4134 If set to 1, attempt to shape the text (for example, reverse the order of
4135 right-to-left text and join Arabic characters) before drawing it.
4136 Otherwise, just draw the text exactly as given.
4137 By default 1 (if supported).
4140 The flags to be used for loading the fonts.
4142 The flags map the corresponding flags supported by libfreetype, and are
4143 a combination of the following values:
4150 @item vertical_layout
4151 @item force_autohint
4154 @item ignore_global_advance_width
4156 @item ignore_transform
4162 Default value is "default".
4164 For more information consult the documentation for the FT_LOAD_*
4168 The color to be used for drawing a shadow behind the drawn text. For the
4169 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
4171 The default value of @var{shadowcolor} is "black".
4175 The x and y offsets for the text shadow position with respect to the
4176 position of the text. They can be either positive or negative
4177 values. The default value for both is "0".
4180 The starting frame number for the n/frame_num variable. The default value
4184 The size in number of spaces to use for rendering the tab.
4188 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
4189 format. It can be used with or without text parameter. @var{timecode_rate}
4190 option must be specified.
4192 @item timecode_rate, rate, r
4193 Set the timecode frame rate (timecode only).
4196 The text string to be drawn. The text must be a sequence of UTF-8
4198 This parameter is mandatory if no file is specified with the parameter
4202 A text file containing text to be drawn. The text must be a sequence
4203 of UTF-8 encoded characters.
4205 This parameter is mandatory if no text string is specified with the
4206 parameter @var{text}.
4208 If both @var{text} and @var{textfile} are specified, an error is thrown.
4211 If set to 1, the @var{textfile} will be reloaded before each frame.
4212 Be sure to update it atomically, or it may be read partially, or even fail.
4216 The expressions which specify the offsets where text will be drawn
4217 within the video frame. They are relative to the top/left border of the
4220 The default value of @var{x} and @var{y} is "0".
4222 See below for the list of accepted constants and functions.
4225 The parameters for @var{x} and @var{y} are expressions containing the
4226 following constants and functions:
4230 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
4234 horizontal and vertical chroma subsample values. For example for the
4235 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4238 the height of each text line
4246 @item max_glyph_a, ascent
4247 the maximum distance from the baseline to the highest/upper grid
4248 coordinate used to place a glyph outline point, for all the rendered
4250 It is a positive value, due to the grid's orientation with the Y axis
4253 @item max_glyph_d, descent
4254 the maximum distance from the baseline to the lowest grid coordinate
4255 used to place a glyph outline point, for all the rendered glyphs.
4256 This is a negative value, due to the grid's orientation, with the Y axis
4260 maximum glyph height, that is the maximum height for all the glyphs
4261 contained in the rendered text, it is equivalent to @var{ascent} -
4265 maximum glyph width, that is the maximum width for all the glyphs
4266 contained in the rendered text
4269 the number of input frame, starting from 0
4271 @item rand(min, max)
4272 return a random number included between @var{min} and @var{max}
4275 The input sample aspect ratio.
4278 timestamp expressed in seconds, NAN if the input timestamp is unknown
4281 the height of the rendered text
4284 the width of the rendered text
4288 the x and y offset coordinates where the text is drawn.
4290 These parameters allow the @var{x} and @var{y} expressions to refer
4291 each other, so you can for example specify @code{y=x/dar}.
4294 @anchor{drawtext_expansion}
4295 @subsection Text expansion
4297 If @option{expansion} is set to @code{strftime},
4298 the filter recognizes strftime() sequences in the provided text and
4299 expands them accordingly. Check the documentation of strftime(). This
4300 feature is deprecated.
4302 If @option{expansion} is set to @code{none}, the text is printed verbatim.
4304 If @option{expansion} is set to @code{normal} (which is the default),
4305 the following expansion mechanism is used.
4307 The backslash character @samp{\}, followed by any character, always expands to
4308 the second character.
4310 Sequence of the form @code{%@{...@}} are expanded. The text between the
4311 braces is a function name, possibly followed by arguments separated by ':'.
4312 If the arguments contain special characters or delimiters (':' or '@}'),
4313 they should be escaped.
4315 Note that they probably must also be escaped as the value for the
4316 @option{text} option in the filter argument string and as the filter
4317 argument in the filtergraph description, and possibly also for the shell,
4318 that makes up to four levels of escaping; using a text file avoids these
4321 The following functions are available:
4326 The expression evaluation result.
4328 It must take one argument specifying the expression to be evaluated,
4329 which accepts the same constants and functions as the @var{x} and
4330 @var{y} values. Note that not all constants should be used, for
4331 example the text size is not known when evaluating the expression, so
4332 the constants @var{text_w} and @var{text_h} will have an undefined
4335 @item expr_int_format, eif
4336 Evaluate the expression's value and output as formatted integer.
4338 The first argument is the expression to be evaluated, just as for the @var{expr} function.
4339 The second argument specifies the output format. Allowed values are @samp{x},
4340 @samp{X}, @samp{d} and @samp{u}. They are treated exactly as in the
4341 @code{printf} function.
4342 The third parameter is optional and sets the number of positions taken by the output.
4343 It can be used to add padding with zeros from the left.
4346 The time at which the filter is running, expressed in UTC.
4347 It can accept an argument: a strftime() format string.
4350 The time at which the filter is running, expressed in the local time zone.
4351 It can accept an argument: a strftime() format string.
4354 Frame metadata. It must take one argument specifying metadata key.
4357 The frame number, starting from 0.
4360 A 1 character description of the current picture type.
4363 The timestamp of the current frame.
4364 It can take up to two arguments.
4366 The first argument is the format of the timestamp; it defaults to @code{flt}
4367 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
4368 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
4370 The second argument is an offset added to the timestamp.
4374 @subsection Examples
4378 Draw "Test Text" with font FreeSerif, using the default values for the
4379 optional parameters.
4382 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
4386 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
4387 and y=50 (counting from the top-left corner of the screen), text is
4388 yellow with a red box around it. Both the text and the box have an
4392 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
4393 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
4396 Note that the double quotes are not necessary if spaces are not used
4397 within the parameter list.
4400 Show the text at the center of the video frame:
4402 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
4406 Show a text line sliding from right to left in the last row of the video
4407 frame. The file @file{LONG_LINE} is assumed to contain a single line
4410 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
4414 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
4416 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
4420 Draw a single green letter "g", at the center of the input video.
4421 The glyph baseline is placed at half screen height.
4423 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
4427 Show text for 1 second every 3 seconds:
4429 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
4433 Use fontconfig to set the font. Note that the colons need to be escaped.
4435 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
4439 Print the date of a real-time encoding (see strftime(3)):
4441 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
4445 Show text fading in and out (appearing/disappearing):
4448 DS=1.0 # display start
4449 DE=10.0 # display end
4450 FID=1.5 # fade in duration
4451 FOD=5 # fade out duration
4452 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 @}"
4457 For more information about libfreetype, check:
4458 @url{http://www.freetype.org/}.
4460 For more information about fontconfig, check:
4461 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
4463 For more information about libfribidi, check:
4464 @url{http://fribidi.org/}.
4468 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
4470 The filter accepts the following options:
4475 Set low and high threshold values used by the Canny thresholding
4478 The high threshold selects the "strong" edge pixels, which are then
4479 connected through 8-connectivity with the "weak" edge pixels selected
4480 by the low threshold.
4482 @var{low} and @var{high} threshold values must be chosen in the range
4483 [0,1], and @var{low} should be lesser or equal to @var{high}.
4485 Default value for @var{low} is @code{20/255}, and default value for @var{high}
4489 Define the drawing mode.
4493 Draw white/gray wires on black background.
4496 Mix the colors to create a paint/cartoon effect.
4499 Default value is @var{wires}.
4502 @subsection Examples
4506 Standard edge detection with custom values for the hysteresis thresholding:
4508 edgedetect=low=0.1:high=0.4
4512 Painting effect without thresholding:
4514 edgedetect=mode=colormix:high=0
4519 Set brightness, contrast, saturation and approximate gamma adjustment.
4521 The filter accepts the following options:
4525 Set the contrast expression. The value must be a float value in range
4526 @code{-2.0} to @code{2.0}. The default value is "0".
4529 Set the brightness expression. The value must be a float value in
4530 range @code{-1.0} to @code{1.0}. The default value is "0".
4533 Set the saturation expression. The value must be a float in
4534 range @code{0.0} to @code{3.0}. The default value is "1".
4537 Set the gamma expression. The value must be a float in range
4538 @code{0.1} to @code{10.0}. The default value is "1".
4541 Set the gamma expression for red. The value must be a float in
4542 range @code{0.1} to @code{10.0}. The default value is "1".
4545 Set the gamma expression for green. The value must be a float in range
4546 @code{0.1} to @code{10.0}. The default value is "1".
4549 Set the gamma expression for blue. The value must be a float in range
4550 @code{0.1} to @code{10.0}. The default value is "1".
4553 Set the gamma weight expression. It can be used to reduce the effect
4554 of a high gamma value on bright image areas, e.g. keep them from
4555 getting overamplified and just plain white. The value must be a float
4556 in range @code{0.0} to @code{1.0}. A value of @code{0.0} turns the
4557 gamma correction all the way down while @code{1.0} leaves it at its
4558 full strength. Default is "1".
4561 Set when the expressions for brightness, contrast, saturation and
4562 gamma expressions are evaluated.
4564 It accepts the following values:
4567 only evaluate expressions once during the filter initialization or
4568 when a command is processed
4571 evaluate expressions for each incoming frame
4574 Default value is @samp{init}.
4577 The expressions accept the following parameters:
4580 frame count of the input frame starting from 0
4583 byte position of the corresponding packet in the input file, NAN if
4587 frame rate of the input video, NAN if the input frame rate is unknown
4590 timestamp expressed in seconds, NAN if the input timestamp is unknown
4593 @subsection Commands
4594 The filter supports the following commands:
4598 Set the contrast expression.
4601 Set the brightness expression.
4604 Set the saturation expression.
4607 Set the gamma expression.
4610 Set the gamma_r expression.
4613 Set gamma_g expression.
4616 Set gamma_b expression.
4619 Set gamma_weight expression.
4621 The command accepts the same syntax of the corresponding option.
4623 If the specified expression is not valid, it is kept at its current
4628 @section extractplanes
4630 Extract color channel components from input video stream into
4631 separate grayscale video streams.
4633 The filter accepts the following option:
4637 Set plane(s) to extract.
4639 Available values for planes are:
4650 Choosing planes not available in the input will result in an error.
4651 That means you cannot select @code{r}, @code{g}, @code{b} planes
4652 with @code{y}, @code{u}, @code{v} planes at same time.
4655 @subsection Examples
4659 Extract luma, u and v color channel component from input video frame
4660 into 3 grayscale outputs:
4662 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
4668 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4670 For each input image, the filter will compute the optimal mapping from
4671 the input to the output given the codebook length, that is the number
4672 of distinct output colors.
4674 This filter accepts the following options.
4677 @item codebook_length, l
4678 Set codebook length. The value must be a positive integer, and
4679 represents the number of distinct output colors. Default value is 256.
4682 Set the maximum number of iterations to apply for computing the optimal
4683 mapping. The higher the value the better the result and the higher the
4684 computation time. Default value is 1.
4687 Set a random seed, must be an integer included between 0 and
4688 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4689 will try to use a good random seed on a best effort basis.
4694 Apply a fade-in/out effect to the input video.
4696 It accepts the following parameters:
4700 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4702 Default is @code{in}.
4704 @item start_frame, s
4705 Specify the number of the frame to start applying the fade
4706 effect at. Default is 0.
4709 The number of frames that the fade effect lasts. At the end of the
4710 fade-in effect, the output video will have the same intensity as the input video.
4711 At the end of the fade-out transition, the output video will be filled with the
4712 selected @option{color}.
4716 If set to 1, fade only alpha channel, if one exists on the input.
4719 @item start_time, st
4720 Specify the timestamp (in seconds) of the frame to start to apply the fade
4721 effect. If both start_frame and start_time are specified, the fade will start at
4722 whichever comes last. Default is 0.
4725 The number of seconds for which the fade effect has to last. At the end of the
4726 fade-in effect the output video will have the same intensity as the input video,
4727 at the end of the fade-out transition the output video will be filled with the
4728 selected @option{color}.
4729 If both duration and nb_frames are specified, duration is used. Default is 0
4730 (nb_frames is used by default).
4733 Specify the color of the fade. Default is "black".
4736 @subsection Examples
4740 Fade in the first 30 frames of video:
4745 The command above is equivalent to:
4751 Fade out the last 45 frames of a 200-frame video:
4754 fade=type=out:start_frame=155:nb_frames=45
4758 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4760 fade=in:0:25, fade=out:975:25
4764 Make the first 5 frames yellow, then fade in from frame 5-24:
4766 fade=in:5:20:color=yellow
4770 Fade in alpha over first 25 frames of video:
4772 fade=in:0:25:alpha=1
4776 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4778 fade=t=in:st=5.5:d=0.5
4784 Apply arbitrary expressions to samples in frequency domain
4788 Adjust the dc value (gain) of the luma plane of the image. The filter
4789 accepts an integer value in range @code{0} to @code{1000}. The default
4790 value is set to @code{0}.
4793 Adjust the dc value (gain) of the 1st chroma plane of the image. The
4794 filter accepts an integer value in range @code{0} to @code{1000}. The
4795 default value is set to @code{0}.
4798 Adjust the dc value (gain) of the 2nd chroma plane of the image. The
4799 filter accepts an integer value in range @code{0} to @code{1000}. The
4800 default value is set to @code{0}.
4803 Set the frequency domain weight expression for the luma plane.
4806 Set the frequency domain weight expression for the 1st chroma plane.
4809 Set the frequency domain weight expression for the 2nd chroma plane.
4811 The filter accepts the following variables:
4814 The coordinates of the current sample.
4818 The width and height of the image.
4821 @subsection Examples
4827 fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
4833 fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
4839 fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
4846 Extract a single field from an interlaced image using stride
4847 arithmetic to avoid wasting CPU time. The output frames are marked as
4850 The filter accepts the following options:
4854 Specify whether to extract the top (if the value is @code{0} or
4855 @code{top}) or the bottom field (if the value is @code{1} or
4861 Field matching filter for inverse telecine. It is meant to reconstruct the
4862 progressive frames from a telecined stream. The filter does not drop duplicated
4863 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4864 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4866 The separation of the field matching and the decimation is notably motivated by
4867 the possibility of inserting a de-interlacing filter fallback between the two.
4868 If the source has mixed telecined and real interlaced content,
4869 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4870 But these remaining combed frames will be marked as interlaced, and thus can be
4871 de-interlaced by a later filter such as @ref{yadif} before decimation.
4873 In addition to the various configuration options, @code{fieldmatch} can take an
4874 optional second stream, activated through the @option{ppsrc} option. If
4875 enabled, the frames reconstruction will be based on the fields and frames from
4876 this second stream. This allows the first input to be pre-processed in order to
4877 help the various algorithms of the filter, while keeping the output lossless
4878 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4879 or brightness/contrast adjustments can help.
4881 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4882 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4883 which @code{fieldmatch} is based on. While the semantic and usage are very
4884 close, some behaviour and options names can differ.
4886 The @ref{decimate} filter currently only works for constant frame rate input.
4887 Do not use @code{fieldmatch} and @ref{decimate} if your input has mixed
4888 telecined and progressive content with changing framerate.
4890 The filter accepts the following options:
4894 Specify the assumed field order of the input stream. Available values are:
4898 Auto detect parity (use FFmpeg's internal parity value).
4900 Assume bottom field first.
4902 Assume top field first.
4905 Note that it is sometimes recommended not to trust the parity announced by the
4908 Default value is @var{auto}.
4911 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4912 sense that it won't risk creating jerkiness due to duplicate frames when
4913 possible, but if there are bad edits or blended fields it will end up
4914 outputting combed frames when a good match might actually exist. On the other
4915 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4916 but will almost always find a good frame if there is one. The other values are
4917 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4918 jerkiness and creating duplicate frames versus finding good matches in sections
4919 with bad edits, orphaned fields, blended fields, etc.
4921 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4923 Available values are:
4927 2-way matching (p/c)
4929 2-way matching, and trying 3rd match if still combed (p/c + n)
4931 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4933 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4934 still combed (p/c + n + u/b)
4936 3-way matching (p/c/n)
4938 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4939 detected as combed (p/c/n + u/b)
4942 The parenthesis at the end indicate the matches that would be used for that
4943 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4946 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4949 Default value is @var{pc_n}.
4952 Mark the main input stream as a pre-processed input, and enable the secondary
4953 input stream as the clean source to pick the fields from. See the filter
4954 introduction for more details. It is similar to the @option{clip2} feature from
4957 Default value is @code{0} (disabled).
4960 Set the field to match from. It is recommended to set this to the same value as
4961 @option{order} unless you experience matching failures with that setting. In
4962 certain circumstances changing the field that is used to match from can have a
4963 large impact on matching performance. Available values are:
4967 Automatic (same value as @option{order}).
4969 Match from the bottom field.
4971 Match from the top field.
4974 Default value is @var{auto}.
4977 Set whether or not chroma is included during the match comparisons. In most
4978 cases it is recommended to leave this enabled. You should set this to @code{0}
4979 only if your clip has bad chroma problems such as heavy rainbowing or other
4980 artifacts. Setting this to @code{0} could also be used to speed things up at
4981 the cost of some accuracy.
4983 Default value is @code{1}.
4987 These define an exclusion band which excludes the lines between @option{y0} and
4988 @option{y1} from being included in the field matching decision. An exclusion
4989 band can be used to ignore subtitles, a logo, or other things that may
4990 interfere with the matching. @option{y0} sets the starting scan line and
4991 @option{y1} sets the ending line; all lines in between @option{y0} and
4992 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4993 @option{y0} and @option{y1} to the same value will disable the feature.
4994 @option{y0} and @option{y1} defaults to @code{0}.
4997 Set the scene change detection threshold as a percentage of maximum change on
4998 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4999 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
5000 @option{scthresh} is @code{[0.0, 100.0]}.
5002 Default value is @code{12.0}.
5005 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
5006 account the combed scores of matches when deciding what match to use as the
5007 final match. Available values are:
5011 No final matching based on combed scores.
5013 Combed scores are only used when a scene change is detected.
5015 Use combed scores all the time.
5018 Default is @var{sc}.
5021 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
5022 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
5023 Available values are:
5027 No forced calculation.
5029 Force p/c/n calculations.
5031 Force p/c/n/u/b calculations.
5034 Default value is @var{none}.
5037 This is the area combing threshold used for combed frame detection. This
5038 essentially controls how "strong" or "visible" combing must be to be detected.
5039 Larger values mean combing must be more visible and smaller values mean combing
5040 can be less visible or strong and still be detected. Valid settings are from
5041 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
5042 be detected as combed). This is basically a pixel difference value. A good
5043 range is @code{[8, 12]}.
5045 Default value is @code{9}.
5048 Sets whether or not chroma is considered in the combed frame decision. Only
5049 disable this if your source has chroma problems (rainbowing, etc.) that are
5050 causing problems for the combed frame detection with chroma enabled. Actually,
5051 using @option{chroma}=@var{0} is usually more reliable, except for the case
5052 where there is chroma only combing in the source.
5054 Default value is @code{0}.
5058 Respectively set the x-axis and y-axis size of the window used during combed
5059 frame detection. This has to do with the size of the area in which
5060 @option{combpel} pixels are required to be detected as combed for a frame to be
5061 declared combed. See the @option{combpel} parameter description for more info.
5062 Possible values are any number that is a power of 2 starting at 4 and going up
5065 Default value is @code{16}.
5068 The number of combed pixels inside any of the @option{blocky} by
5069 @option{blockx} size blocks on the frame for the frame to be detected as
5070 combed. While @option{cthresh} controls how "visible" the combing must be, this
5071 setting controls "how much" combing there must be in any localized area (a
5072 window defined by the @option{blockx} and @option{blocky} settings) on the
5073 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
5074 which point no frames will ever be detected as combed). This setting is known
5075 as @option{MI} in TFM/VFM vocabulary.
5077 Default value is @code{80}.
5080 @anchor{p/c/n/u/b meaning}
5081 @subsection p/c/n/u/b meaning
5083 @subsubsection p/c/n
5085 We assume the following telecined stream:
5088 Top fields: 1 2 2 3 4
5089 Bottom fields: 1 2 3 4 4
5092 The numbers correspond to the progressive frame the fields relate to. Here, the
5093 first two frames are progressive, the 3rd and 4th are combed, and so on.
5095 When @code{fieldmatch} is configured to run a matching from bottom
5096 (@option{field}=@var{bottom}) this is how this input stream get transformed:
5101 B 1 2 3 4 4 <-- matching reference
5110 As a result of the field matching, we can see that some frames get duplicated.
5111 To perform a complete inverse telecine, you need to rely on a decimation filter
5112 after this operation. See for instance the @ref{decimate} filter.
5114 The same operation now matching from top fields (@option{field}=@var{top})
5119 T 1 2 2 3 4 <-- matching reference
5129 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
5130 basically, they refer to the frame and field of the opposite parity:
5133 @item @var{p} matches the field of the opposite parity in the previous frame
5134 @item @var{c} matches the field of the opposite parity in the current frame
5135 @item @var{n} matches the field of the opposite parity in the next frame
5140 The @var{u} and @var{b} matching are a bit special in the sense that they match
5141 from the opposite parity flag. In the following examples, we assume that we are
5142 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
5143 'x' is placed above and below each matched fields.
5145 With bottom matching (@option{field}=@var{bottom}):
5150 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
5151 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
5159 With top matching (@option{field}=@var{top}):
5164 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
5165 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
5173 @subsection Examples
5175 Simple IVTC of a top field first telecined stream:
5177 fieldmatch=order=tff:combmatch=none, decimate
5180 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
5182 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
5187 Transform the field order of the input video.
5189 It accepts the following parameters:
5194 The output field order. Valid values are @var{tff} for top field first or @var{bff}
5195 for bottom field first.
5198 The default value is @samp{tff}.
5200 The transformation is done by shifting the picture content up or down
5201 by one line, and filling the remaining line with appropriate picture content.
5202 This method is consistent with most broadcast field order converters.
5204 If the input video is not flagged as being interlaced, or it is already
5205 flagged as being of the required output field order, then this filter does
5206 not alter the incoming video.
5208 It is very useful when converting to or from PAL DV material,
5209 which is bottom field first.
5213 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
5218 Buffer input images and send them when they are requested.
5220 It is mainly useful when auto-inserted by the libavfilter
5223 It does not take parameters.
5227 Find a rectangular object
5229 It accepts the following options:
5233 Filepath of the object image, needs to be in gray8.
5236 Detection threshold, default is 0.5.
5239 Number of mipmaps, default is 3.
5241 @item xmin, ymin, xmax, ymax
5242 Specifies the rectangle in which to search.
5245 @subsection Examples
5249 Generate a representative palette of a given video using @command{ffmpeg}:
5251 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
5257 Cover a rectangular object
5259 It accepts the following options:
5263 Filepath of the optional cover image, needs to be in yuv420.
5268 It accepts the following values:
5271 cover it by the supplied image
5273 cover it by interpolating the surrounding pixels
5276 Default value is @var{blur}.
5279 @subsection Examples
5283 Generate a representative palette of a given video using @command{ffmpeg}:
5285 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
5292 Convert the input video to one of the specified pixel formats.
5293 Libavfilter will try to pick one that is suitable as input to
5296 It accepts the following parameters:
5300 A '|'-separated list of pixel format names, such as
5301 "pix_fmts=yuv420p|monow|rgb24".
5305 @subsection Examples
5309 Convert the input video to the @var{yuv420p} format
5311 format=pix_fmts=yuv420p
5314 Convert the input video to any of the formats in the list
5316 format=pix_fmts=yuv420p|yuv444p|yuv410p
5323 Convert the video to specified constant frame rate by duplicating or dropping
5324 frames as necessary.
5326 It accepts the following parameters:
5330 The desired output frame rate. The default is @code{25}.
5335 Possible values are:
5338 zero round towards 0
5342 round towards -infinity
5344 round towards +infinity
5348 The default is @code{near}.
5351 Assume the first PTS should be the given value, in seconds. This allows for
5352 padding/trimming at the start of stream. By default, no assumption is made
5353 about the first frame's expected PTS, so no padding or trimming is done.
5354 For example, this could be set to 0 to pad the beginning with duplicates of
5355 the first frame if a video stream starts after the audio stream or to trim any
5356 frames with a negative PTS.
5360 Alternatively, the options can be specified as a flat string:
5361 @var{fps}[:@var{round}].
5363 See also the @ref{setpts} filter.
5365 @subsection Examples
5369 A typical usage in order to set the fps to 25:
5375 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
5377 fps=fps=film:round=near
5383 Pack two different video streams into a stereoscopic video, setting proper
5384 metadata on supported codecs. The two views should have the same size and
5385 framerate and processing will stop when the shorter video ends. Please note
5386 that you may conveniently adjust view properties with the @ref{scale} and
5389 It accepts the following parameters:
5393 The desired packing format. Supported values are:
5398 The views are next to each other (default).
5401 The views are on top of each other.
5404 The views are packed by line.
5407 The views are packed by column.
5410 The views are temporally interleaved.
5419 # Convert left and right views into a frame-sequential video
5420 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
5422 # Convert views into a side-by-side video with the same output resolution as the input
5423 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
5428 Select one frame every N-th frame.
5430 This filter accepts the following option:
5433 Select frame after every @code{step} frames.
5434 Allowed values are positive integers higher than 0. Default value is @code{1}.
5440 Apply a frei0r effect to the input video.
5442 To enable the compilation of this filter, you need to install the frei0r
5443 header and configure FFmpeg with @code{--enable-frei0r}.
5445 It accepts the following parameters:
5450 The name of the frei0r effect to load. If the environment variable
5451 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
5452 directories specified by the colon-separated list in @env{FREIOR_PATH}.
5453 Otherwise, the standard frei0r paths are searched, in this order:
5454 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
5455 @file{/usr/lib/frei0r-1/}.
5458 A '|'-separated list of parameters to pass to the frei0r effect.
5462 A frei0r effect parameter can be a boolean (its value is either
5463 "y" or "n"), a double, a color (specified as
5464 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
5465 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
5466 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
5467 @var{X} and @var{Y} are floating point numbers) and/or a string.
5469 The number and types of parameters depend on the loaded effect. If an
5470 effect parameter is not specified, the default value is set.
5472 @subsection Examples
5476 Apply the distort0r effect, setting the first two double parameters:
5478 frei0r=filter_name=distort0r:filter_params=0.5|0.01
5482 Apply the colordistance effect, taking a color as the first parameter:
5484 frei0r=colordistance:0.2/0.3/0.4
5485 frei0r=colordistance:violet
5486 frei0r=colordistance:0x112233
5490 Apply the perspective effect, specifying the top left and top right image
5493 frei0r=perspective:0.2/0.2|0.8/0.2
5497 For more information, see
5498 @url{http://frei0r.dyne.org}
5502 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
5504 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
5505 processing filter, one of them is performed once per block, not per pixel.
5506 This allows for much higher speed.
5508 The filter accepts the following options:
5512 Set quality. This option defines the number of levels for averaging. It accepts
5513 an integer in the range 4-5. Default value is @code{4}.
5516 Force a constant quantization parameter. It accepts an integer in range 0-63.
5517 If not set, the filter will use the QP from the video stream (if available).
5520 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
5521 more details but also more artifacts, while higher values make the image smoother
5522 but also blurrier. Default value is @code{0} − PSNR optimal.
5525 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
5526 option may cause flicker since the B-Frames have often larger QP. Default is
5527 @code{0} (not enabled).
5533 The filter accepts the following options:
5537 Set the luminance expression.
5539 Set the chrominance blue expression.
5541 Set the chrominance red expression.
5543 Set the alpha expression.
5545 Set the red expression.
5547 Set the green expression.
5549 Set the blue expression.
5552 The colorspace is selected according to the specified options. If one
5553 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
5554 options is specified, the filter will automatically select a YCbCr
5555 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
5556 @option{blue_expr} options is specified, it will select an RGB
5559 If one of the chrominance expression is not defined, it falls back on the other
5560 one. If no alpha expression is specified it will evaluate to opaque value.
5561 If none of chrominance expressions are specified, they will evaluate
5562 to the luminance expression.
5564 The expressions can use the following variables and functions:
5568 The sequential number of the filtered frame, starting from @code{0}.
5572 The coordinates of the current sample.
5576 The width and height of the image.
5580 Width and height scale depending on the currently filtered plane. It is the
5581 ratio between the corresponding luma plane number of pixels and the current
5582 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
5583 @code{0.5,0.5} for chroma planes.
5586 Time of the current frame, expressed in seconds.
5589 Return the value of the pixel at location (@var{x},@var{y}) of the current
5593 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
5597 Return the value of the pixel at location (@var{x},@var{y}) of the
5598 blue-difference chroma plane. Return 0 if there is no such plane.
5601 Return the value of the pixel at location (@var{x},@var{y}) of the
5602 red-difference chroma plane. Return 0 if there is no such plane.
5607 Return the value of the pixel at location (@var{x},@var{y}) of the
5608 red/green/blue component. Return 0 if there is no such component.
5611 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
5612 plane. Return 0 if there is no such plane.
5615 For functions, if @var{x} and @var{y} are outside the area, the value will be
5616 automatically clipped to the closer edge.
5618 @subsection Examples
5622 Flip the image horizontally:
5628 Generate a bidimensional sine wave, with angle @code{PI/3} and a
5629 wavelength of 100 pixels:
5631 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
5635 Generate a fancy enigmatic moving light:
5637 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
5641 Generate a quick emboss effect:
5643 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
5647 Modify RGB components depending on pixel position:
5649 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
5653 Create a radial gradient that is the same size as the input (also see
5654 the @ref{vignette} filter):
5656 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
5660 Create a linear gradient to use as a mask for another filter, then
5661 compose with @ref{overlay}. In this example the video will gradually
5662 become more blurry from the top to the bottom of the y-axis as defined
5663 by the linear gradient:
5665 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
5671 Fix the banding artifacts that are sometimes introduced into nearly flat
5672 regions by truncation to 8bit color depth.
5673 Interpolate the gradients that should go where the bands are, and
5676 It is designed for playback only. Do not use it prior to
5677 lossy compression, because compression tends to lose the dither and
5678 bring back the bands.
5680 It accepts the following parameters:
5685 The maximum amount by which the filter will change any one pixel. This is also
5686 the threshold for detecting nearly flat regions. Acceptable values range from
5687 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
5691 The neighborhood to fit the gradient to. A larger radius makes for smoother
5692 gradients, but also prevents the filter from modifying the pixels near detailed
5693 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
5694 values will be clipped to the valid range.
5698 Alternatively, the options can be specified as a flat string:
5699 @var{strength}[:@var{radius}]
5701 @subsection Examples
5705 Apply the filter with a @code{3.5} strength and radius of @code{8}:
5711 Specify radius, omitting the strength (which will fall-back to the default
5722 Apply a Hald CLUT to a video stream.
5724 First input is the video stream to process, and second one is the Hald CLUT.
5725 The Hald CLUT input can be a simple picture or a complete video stream.
5727 The filter accepts the following options:
5731 Force termination when the shortest input terminates. Default is @code{0}.
5733 Continue applying the last CLUT after the end of the stream. A value of
5734 @code{0} disable the filter after the last frame of the CLUT is reached.
5735 Default is @code{1}.
5738 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
5739 filters share the same internals).
5741 More information about the Hald CLUT can be found on Eskil Steenberg's website
5742 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
5744 @subsection Workflow examples
5746 @subsubsection Hald CLUT video stream
5748 Generate an identity Hald CLUT stream altered with various effects:
5750 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
5753 Note: make sure you use a lossless codec.
5755 Then use it with @code{haldclut} to apply it on some random stream:
5757 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
5760 The Hald CLUT will be applied to the 10 first seconds (duration of
5761 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
5762 to the remaining frames of the @code{mandelbrot} stream.
5764 @subsubsection Hald CLUT with preview
5766 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
5767 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
5768 biggest possible square starting at the top left of the picture. The remaining
5769 padding pixels (bottom or right) will be ignored. This area can be used to add
5770 a preview of the Hald CLUT.
5772 Typically, the following generated Hald CLUT will be supported by the
5773 @code{haldclut} filter:
5776 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
5777 pad=iw+320 [padded_clut];
5778 smptebars=s=320x256, split [a][b];
5779 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
5780 [main][b] overlay=W-320" -frames:v 1 clut.png
5783 It contains the original and a preview of the effect of the CLUT: SMPTE color
5784 bars are displayed on the right-top, and below the same color bars processed by
5787 Then, the effect of this Hald CLUT can be visualized with:
5789 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
5794 Flip the input video horizontally.
5796 For example, to horizontally flip the input video with @command{ffmpeg}:
5798 ffmpeg -i in.avi -vf "hflip" out.avi
5802 This filter applies a global color histogram equalization on a
5805 It can be used to correct video that has a compressed range of pixel
5806 intensities. The filter redistributes the pixel intensities to
5807 equalize their distribution across the intensity range. It may be
5808 viewed as an "automatically adjusting contrast filter". This filter is
5809 useful only for correcting degraded or poorly captured source
5812 The filter accepts the following options:
5816 Determine the amount of equalization to be applied. As the strength
5817 is reduced, the distribution of pixel intensities more-and-more
5818 approaches that of the input frame. The value must be a float number
5819 in the range [0,1] and defaults to 0.200.
5822 Set the maximum intensity that can generated and scale the output
5823 values appropriately. The strength should be set as desired and then
5824 the intensity can be limited if needed to avoid washing-out. The value
5825 must be a float number in the range [0,1] and defaults to 0.210.
5828 Set the antibanding level. If enabled the filter will randomly vary
5829 the luminance of output pixels by a small amount to avoid banding of
5830 the histogram. Possible values are @code{none}, @code{weak} or
5831 @code{strong}. It defaults to @code{none}.
5836 Compute and draw a color distribution histogram for the input video.
5838 The computed histogram is a representation of the color component
5839 distribution in an image.
5841 The filter accepts the following options:
5847 It accepts the following values:
5850 Standard histogram that displays the color components distribution in an
5851 image. Displays color graph for each color component. Shows distribution of
5852 the Y, U, V, A or R, G, B components, depending on input format, in the
5853 current frame. Below each graph a color component scale meter is shown.
5856 Displays chroma values (U/V color placement) in a two dimensional
5857 graph (which is called a vectorscope). The brighter a pixel in the
5858 vectorscope, the more pixels of the input frame correspond to that pixel
5859 (i.e., more pixels have this chroma value). The V component is displayed on
5860 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5861 side being V = 255. The U component is displayed on the vertical (Y) axis,
5862 with the top representing U = 0 and the bottom representing U = 255.
5864 The position of a white pixel in the graph corresponds to the chroma value of
5865 a pixel of the input clip. The graph can therefore be used to read the hue
5866 (color flavor) and the saturation (the dominance of the hue in the color). As
5867 the hue of a color changes, it moves around the square. At the center of the
5868 square the saturation is zero, which means that the corresponding pixel has no
5869 color. If the amount of a specific color is increased (while leaving the other
5870 colors unchanged) the saturation increases, and the indicator moves towards
5871 the edge of the square.
5874 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5878 Per row/column color component graph. In row mode, the graph on the left side
5879 represents color component value 0 and the right side represents value = 255.
5880 In column mode, the top side represents color component value = 0 and bottom
5881 side represents value = 255.
5883 Default value is @code{levels}.
5886 Set height of level in @code{levels}. Default value is @code{200}.
5887 Allowed range is [50, 2048].
5890 Set height of color scale in @code{levels}. Default value is @code{12}.
5891 Allowed range is [0, 40].
5894 Set step for @code{waveform} mode. Smaller values are useful to find out how
5895 many values of the same luminance are distributed across input rows/columns.
5896 Default value is @code{10}. Allowed range is [1, 255].
5899 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5900 Default is @code{row}.
5902 @item waveform_mirror
5903 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5904 means mirrored. In mirrored mode, higher values will be represented on the left
5905 side for @code{row} mode and at the top for @code{column} mode. Default is
5906 @code{0} (unmirrored).
5909 Set display mode for @code{waveform} and @code{levels}.
5910 It accepts the following values:
5913 Display separate graph for the color components side by side in
5914 @code{row} waveform mode or one below the other in @code{column} waveform mode
5915 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5916 per color component graphs are placed below each other.
5918 Using this display mode in @code{waveform} histogram mode makes it easy to
5919 spot color casts in the highlights and shadows of an image, by comparing the
5920 contours of the top and the bottom graphs of each waveform. Since whites,
5921 grays, and blacks are characterized by exactly equal amounts of red, green,
5922 and blue, neutral areas of the picture should display three waveforms of
5923 roughly equal width/height. If not, the correction is easy to perform by
5924 making level adjustments the three waveforms.
5927 Presents information identical to that in the @code{parade}, except
5928 that the graphs representing color components are superimposed directly
5931 This display mode in @code{waveform} histogram mode makes it easier to spot
5932 relative differences or similarities in overlapping areas of the color
5933 components that are supposed to be identical, such as neutral whites, grays,
5936 Default is @code{parade}.
5939 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5940 Default is @code{linear}.
5943 @subsection Examples
5948 Calculate and draw histogram:
5950 ffplay -i input -vf histogram
5958 This is a high precision/quality 3d denoise filter. It aims to reduce
5959 image noise, producing smooth images and making still images really
5960 still. It should enhance compressibility.
5962 It accepts the following optional parameters:
5966 A non-negative floating point number which specifies spatial luma strength.
5969 @item chroma_spatial
5970 A non-negative floating point number which specifies spatial chroma strength.
5971 It defaults to 3.0*@var{luma_spatial}/4.0.
5974 A floating point number which specifies luma temporal strength. It defaults to
5975 6.0*@var{luma_spatial}/4.0.
5978 A floating point number which specifies chroma temporal strength. It defaults to
5979 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5984 Apply a high-quality magnification filter designed for pixel art. This filter
5985 was originally created by Maxim Stepin.
5987 It accepts the following option:
5991 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
5992 @code{hq3x} and @code{4} for @code{hq4x}.
5993 Default is @code{3}.
5998 Modify the hue and/or the saturation of the input.
6000 It accepts the following parameters:
6004 Specify the hue angle as a number of degrees. It accepts an expression,
6005 and defaults to "0".
6008 Specify the saturation in the [-10,10] range. It accepts an expression and
6012 Specify the hue angle as a number of radians. It accepts an
6013 expression, and defaults to "0".
6016 Specify the brightness in the [-10,10] range. It accepts an expression and
6020 @option{h} and @option{H} are mutually exclusive, and can't be
6021 specified at the same time.
6023 The @option{b}, @option{h}, @option{H} and @option{s} option values are
6024 expressions containing the following constants:
6028 frame count of the input frame starting from 0
6031 presentation timestamp of the input frame expressed in time base units
6034 frame rate of the input video, NAN if the input frame rate is unknown
6037 timestamp expressed in seconds, NAN if the input timestamp is unknown
6040 time base of the input video
6043 @subsection Examples
6047 Set the hue to 90 degrees and the saturation to 1.0:
6053 Same command but expressing the hue in radians:
6059 Rotate hue and make the saturation swing between 0
6060 and 2 over a period of 1 second:
6062 hue="H=2*PI*t: s=sin(2*PI*t)+1"
6066 Apply a 3 seconds saturation fade-in effect starting at 0:
6071 The general fade-in expression can be written as:
6073 hue="s=min(0\, max((t-START)/DURATION\, 1))"
6077 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
6079 hue="s=max(0\, min(1\, (8-t)/3))"
6082 The general fade-out expression can be written as:
6084 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
6089 @subsection Commands
6091 This filter supports the following commands:
6097 Modify the hue and/or the saturation and/or brightness of the input video.
6098 The command accepts the same syntax of the corresponding option.
6100 If the specified expression is not valid, it is kept at its current
6106 Detect video interlacing type.
6108 This filter tries to detect if the input frames as interlaced, progressive,
6109 top or bottom field first. It will also try and detect fields that are
6110 repeated between adjacent frames (a sign of telecine).
6112 Single frame detection considers only immediately adjacent frames when classifying each frame.
6113 Multiple frame detection incorporates the classification history of previous frames.
6115 The filter will log these metadata values:
6118 @item single.current_frame
6119 Detected type of current frame using single-frame detection. One of:
6120 ``tff'' (top field first), ``bff'' (bottom field first),
6121 ``progressive'', or ``undetermined''
6124 Cumulative number of frames detected as top field first using single-frame detection.
6127 Cumulative number of frames detected as top field first using multiple-frame detection.
6130 Cumulative number of frames detected as bottom field first using single-frame detection.
6132 @item multiple.current_frame
6133 Detected type of current frame using multiple-frame detection. One of:
6134 ``tff'' (top field first), ``bff'' (bottom field first),
6135 ``progressive'', or ``undetermined''
6138 Cumulative number of frames detected as bottom field first using multiple-frame detection.
6140 @item single.progressive
6141 Cumulative number of frames detected as progressive using single-frame detection.
6143 @item multiple.progressive
6144 Cumulative number of frames detected as progressive using multiple-frame detection.
6146 @item single.undetermined
6147 Cumulative number of frames that could not be classified using single-frame detection.
6149 @item multiple.undetermined
6150 Cumulative number of frames that could not be classified using multiple-frame detection.
6152 @item repeated.current_frame
6153 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
6155 @item repeated.neither
6156 Cumulative number of frames with no repeated field.
6159 Cumulative number of frames with the top field repeated from the previous frame's top field.
6161 @item repeated.bottom
6162 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
6165 The filter accepts the following options:
6169 Set interlacing threshold.
6171 Set progressive threshold.
6173 Threshold for repeated field detection.
6175 Number of frames after which a given frame's contribution to the
6176 statistics is halved (i.e., it contributes only 0.5 to it's
6177 classification). The default of 0 means that all frames seen are given
6178 full weight of 1.0 forever.
6179 @item analyze_interlaced_flag
6180 When this is not 0 then idet will use the specified number of frames to determine
6181 if the interlaced flag is accurate, it will not count undetermined frames.
6182 If the flag is found to be accurate it will be used without any further
6183 computations, if it is found to be inaccurate it will be cleared without any
6184 further computations. This allows inserting the idet filter as a low computational
6185 method to clean up the interlaced flag
6190 Deinterleave or interleave fields.
6192 This filter allows one to process interlaced images fields without
6193 deinterlacing them. Deinterleaving splits the input frame into 2
6194 fields (so called half pictures). Odd lines are moved to the top
6195 half of the output image, even lines to the bottom half.
6196 You can process (filter) them independently and then re-interleave them.
6198 The filter accepts the following options:
6202 @item chroma_mode, c
6204 Available values for @var{luma_mode}, @var{chroma_mode} and
6205 @var{alpha_mode} are:
6211 @item deinterleave, d
6212 Deinterleave fields, placing one above the other.
6215 Interleave fields. Reverse the effect of deinterleaving.
6217 Default value is @code{none}.
6220 @item chroma_swap, cs
6221 @item alpha_swap, as
6222 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
6227 Simple interlacing filter from progressive contents. This interleaves upper (or
6228 lower) lines from odd frames with lower (or upper) lines from even frames,
6229 halving the frame rate and preserving image height.
6232 Original Original New Frame
6233 Frame 'j' Frame 'j+1' (tff)
6234 ========== =========== ==================
6235 Line 0 --------------------> Frame 'j' Line 0
6236 Line 1 Line 1 ----> Frame 'j+1' Line 1
6237 Line 2 ---------------------> Frame 'j' Line 2
6238 Line 3 Line 3 ----> Frame 'j+1' Line 3
6240 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
6243 It accepts the following optional parameters:
6247 This determines whether the interlaced frame is taken from the even
6248 (tff - default) or odd (bff) lines of the progressive frame.
6251 Enable (default) or disable the vertical lowpass filter to avoid twitter
6252 interlacing and reduce moire patterns.
6257 Deinterlace input video by applying Donald Graft's adaptive kernel
6258 deinterling. Work on interlaced parts of a video to produce
6261 The description of the accepted parameters follows.
6265 Set the threshold which affects the filter's tolerance when
6266 determining if a pixel line must be processed. It must be an integer
6267 in the range [0,255] and defaults to 10. A value of 0 will result in
6268 applying the process on every pixels.
6271 Paint pixels exceeding the threshold value to white if set to 1.
6275 Set the fields order. Swap fields if set to 1, leave fields alone if
6279 Enable additional sharpening if set to 1. Default is 0.
6282 Enable twoway sharpening if set to 1. Default is 0.
6285 @subsection Examples
6289 Apply default values:
6291 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
6295 Enable additional sharpening:
6301 Paint processed pixels in white:
6307 @section lenscorrection
6309 Correct radial lens distortion
6311 This filter can be used to correct for radial distortion as can result from the use
6312 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
6313 one can use tools available for example as part of opencv or simply trial-and-error.
6314 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
6315 and extract the k1 and k2 coefficients from the resulting matrix.
6317 Note that effectively the same filter is available in the open-source tools Krita and
6318 Digikam from the KDE project.
6320 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
6321 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
6322 brightness distribution, so you may want to use both filters together in certain
6323 cases, though you will have to take care of ordering, i.e. whether vignetting should
6324 be applied before or after lens correction.
6328 The filter accepts the following options:
6332 Relative x-coordinate of the focal point of the image, and thereby the center of the
6333 distortion. This value has a range [0,1] and is expressed as fractions of the image
6336 Relative y-coordinate of the focal point of the image, and thereby the center of the
6337 distortion. This value has a range [0,1] and is expressed as fractions of the image
6340 Coefficient of the quadratic correction term. 0.5 means no correction.
6342 Coefficient of the double quadratic correction term. 0.5 means no correction.
6345 The formula that generates the correction is:
6347 @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)
6349 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
6350 distances from the focal point in the source and target images, respectively.
6355 Apply a 3D LUT to an input video.
6357 The filter accepts the following options:
6361 Set the 3D LUT file name.
6363 Currently supported formats:
6375 Select interpolation mode.
6377 Available values are:
6381 Use values from the nearest defined point.
6383 Interpolate values using the 8 points defining a cube.
6385 Interpolate values using a tetrahedron.
6389 @section lut, lutrgb, lutyuv
6391 Compute a look-up table for binding each pixel component input value
6392 to an output value, and apply it to the input video.
6394 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
6395 to an RGB input video.
6397 These filters accept the following parameters:
6400 set first pixel component expression
6402 set second pixel component expression
6404 set third pixel component expression
6406 set fourth pixel component expression, corresponds to the alpha component
6409 set red component expression
6411 set green component expression
6413 set blue component expression
6415 alpha component expression
6418 set Y/luminance component expression
6420 set U/Cb component expression
6422 set V/Cr component expression
6425 Each of them specifies the expression to use for computing the lookup table for
6426 the corresponding pixel component values.
6428 The exact component associated to each of the @var{c*} options depends on the
6431 The @var{lut} filter requires either YUV or RGB pixel formats in input,
6432 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
6434 The expressions can contain the following constants and functions:
6439 The input width and height.
6442 The input value for the pixel component.
6445 The input value, clipped to the @var{minval}-@var{maxval} range.
6448 The maximum value for the pixel component.
6451 The minimum value for the pixel component.
6454 The negated value for the pixel component value, clipped to the
6455 @var{minval}-@var{maxval} range; it corresponds to the expression
6456 "maxval-clipval+minval".
6459 The computed value in @var{val}, clipped to the
6460 @var{minval}-@var{maxval} range.
6462 @item gammaval(gamma)
6463 The computed gamma correction value of the pixel component value,
6464 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
6466 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
6470 All expressions default to "val".
6472 @subsection Examples
6478 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
6479 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
6482 The above is the same as:
6484 lutrgb="r=negval:g=negval:b=negval"
6485 lutyuv="y=negval:u=negval:v=negval"
6495 Remove chroma components, turning the video into a graytone image:
6497 lutyuv="u=128:v=128"
6501 Apply a luma burning effect:
6507 Remove green and blue components:
6513 Set a constant alpha channel value on input:
6515 format=rgba,lutrgb=a="maxval-minval/2"
6519 Correct luminance gamma by a factor of 0.5:
6521 lutyuv=y=gammaval(0.5)
6525 Discard least significant bits of luma:
6527 lutyuv=y='bitand(val, 128+64+32)'
6531 @section mergeplanes
6533 Merge color channel components from several video streams.
6535 The filter accepts up to 4 input streams, and merge selected input
6536 planes to the output video.
6538 This filter accepts the following options:
6541 Set input to output plane mapping. Default is @code{0}.
6543 The mappings is specified as a bitmap. It should be specified as a
6544 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
6545 mapping for the first plane of the output stream. 'A' sets the number of
6546 the input stream to use (from 0 to 3), and 'a' the plane number of the
6547 corresponding input to use (from 0 to 3). The rest of the mappings is
6548 similar, 'Bb' describes the mapping for the output stream second
6549 plane, 'Cc' describes the mapping for the output stream third plane and
6550 'Dd' describes the mapping for the output stream fourth plane.
6553 Set output pixel format. Default is @code{yuva444p}.
6556 @subsection Examples
6560 Merge three gray video streams of same width and height into single video stream:
6562 [a0][a1][a2]mergeplanes=0x001020:yuv444p
6566 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
6568 [a0][a1]mergeplanes=0x00010210:yuva444p
6572 Swap Y and A plane in yuva444p stream:
6574 format=yuva444p,mergeplanes=0x03010200:yuva444p
6578 Swap U and V plane in yuv420p stream:
6580 format=yuv420p,mergeplanes=0x000201:yuv420p
6584 Cast a rgb24 clip to yuv444p:
6586 format=rgb24,mergeplanes=0x000102:yuv444p
6592 Apply motion-compensation deinterlacing.
6594 It needs one field per frame as input and must thus be used together
6595 with yadif=1/3 or equivalent.
6597 This filter accepts the following options:
6600 Set the deinterlacing mode.
6602 It accepts one of the following values:
6607 use iterative motion estimation
6609 like @samp{slow}, but use multiple reference frames.
6611 Default value is @samp{fast}.
6614 Set the picture field parity assumed for the input video. It must be
6615 one of the following values:
6619 assume top field first
6621 assume bottom field first
6624 Default value is @samp{bff}.
6627 Set per-block quantization parameter (QP) used by the internal
6630 Higher values should result in a smoother motion vector field but less
6631 optimal individual vectors. Default value is 1.
6636 Drop frames that do not differ greatly from the previous frame in
6637 order to reduce frame rate.
6639 The main use of this filter is for very-low-bitrate encoding
6640 (e.g. streaming over dialup modem), but it could in theory be used for
6641 fixing movies that were inverse-telecined incorrectly.
6643 A description of the accepted options follows.
6647 Set the maximum number of consecutive frames which can be dropped (if
6648 positive), or the minimum interval between dropped frames (if
6649 negative). If the value is 0, the frame is dropped unregarding the
6650 number of previous sequentially dropped frames.
6657 Set the dropping threshold values.
6659 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
6660 represent actual pixel value differences, so a threshold of 64
6661 corresponds to 1 unit of difference for each pixel, or the same spread
6662 out differently over the block.
6664 A frame is a candidate for dropping if no 8x8 blocks differ by more
6665 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
6666 meaning the whole image) differ by more than a threshold of @option{lo}.
6668 Default value for @option{hi} is 64*12, default value for @option{lo} is
6669 64*5, and default value for @option{frac} is 0.33.
6677 It accepts an integer in input; if non-zero it negates the
6678 alpha component (if available). The default value in input is 0.
6682 Force libavfilter not to use any of the specified pixel formats for the
6683 input to the next filter.
6685 It accepts the following parameters:
6689 A '|'-separated list of pixel format names, such as
6690 apix_fmts=yuv420p|monow|rgb24".
6694 @subsection Examples
6698 Force libavfilter to use a format different from @var{yuv420p} for the
6699 input to the vflip filter:
6701 noformat=pix_fmts=yuv420p,vflip
6705 Convert the input video to any of the formats not contained in the list:
6707 noformat=yuv420p|yuv444p|yuv410p
6713 Add noise on video input frame.
6715 The filter accepts the following options:
6723 Set noise seed for specific pixel component or all pixel components in case
6724 of @var{all_seed}. Default value is @code{123457}.
6726 @item all_strength, alls
6727 @item c0_strength, c0s
6728 @item c1_strength, c1s
6729 @item c2_strength, c2s
6730 @item c3_strength, c3s
6731 Set noise strength for specific pixel component or all pixel components in case
6732 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
6734 @item all_flags, allf
6739 Set pixel component flags or set flags for all components if @var{all_flags}.
6740 Available values for component flags are:
6743 averaged temporal noise (smoother)
6745 mix random noise with a (semi)regular pattern
6747 temporal noise (noise pattern changes between frames)
6749 uniform noise (gaussian otherwise)
6753 @subsection Examples
6755 Add temporal and uniform noise to input video:
6757 noise=alls=20:allf=t+u
6762 Pass the video source unchanged to the output.
6766 Apply a video transform using libopencv.
6768 To enable this filter, install the libopencv library and headers and
6769 configure FFmpeg with @code{--enable-libopencv}.
6771 It accepts the following parameters:
6776 The name of the libopencv filter to apply.
6779 The parameters to pass to the libopencv filter. If not specified, the default
6784 Refer to the official libopencv documentation for more precise
6786 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
6788 Several libopencv filters are supported; see the following subsections.
6793 Dilate an image by using a specific structuring element.
6794 It corresponds to the libopencv function @code{cvDilate}.
6796 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
6798 @var{struct_el} represents a structuring element, and has the syntax:
6799 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
6801 @var{cols} and @var{rows} represent the number of columns and rows of
6802 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
6803 point, and @var{shape} the shape for the structuring element. @var{shape}
6804 must be "rect", "cross", "ellipse", or "custom".
6806 If the value for @var{shape} is "custom", it must be followed by a
6807 string of the form "=@var{filename}". The file with name
6808 @var{filename} is assumed to represent a binary image, with each
6809 printable character corresponding to a bright pixel. When a custom
6810 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
6811 or columns and rows of the read file are assumed instead.
6813 The default value for @var{struct_el} is "3x3+0x0/rect".
6815 @var{nb_iterations} specifies the number of times the transform is
6816 applied to the image, and defaults to 1.
6820 # Use the default values
6823 # Dilate using a structuring element with a 5x5 cross, iterating two times
6824 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
6826 # Read the shape from the file diamond.shape, iterating two times.
6827 # The file diamond.shape may contain a pattern of characters like this
6833 # The specified columns and rows are ignored
6834 # but the anchor point coordinates are not
6835 ocv=dilate:0x0+2x2/custom=diamond.shape|2
6840 Erode an image by using a specific structuring element.
6841 It corresponds to the libopencv function @code{cvErode}.
6843 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
6844 with the same syntax and semantics as the @ref{dilate} filter.
6848 Smooth the input video.
6850 The filter takes the following parameters:
6851 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
6853 @var{type} is the type of smooth filter to apply, and must be one of
6854 the following values: "blur", "blur_no_scale", "median", "gaussian",
6855 or "bilateral". The default value is "gaussian".
6857 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
6858 depend on the smooth type. @var{param1} and
6859 @var{param2} accept integer positive values or 0. @var{param3} and
6860 @var{param4} accept floating point values.
6862 The default value for @var{param1} is 3. The default value for the
6863 other parameters is 0.
6865 These parameters correspond to the parameters assigned to the
6866 libopencv function @code{cvSmooth}.
6871 Overlay one video on top of another.
6873 It takes two inputs and has one output. The first input is the "main"
6874 video on which the second input is overlaid.
6876 It accepts the following parameters:
6878 A description of the accepted options follows.
6883 Set the expression for the x and y coordinates of the overlaid video
6884 on the main video. Default value is "0" for both expressions. In case
6885 the expression is invalid, it is set to a huge value (meaning that the
6886 overlay will not be displayed within the output visible area).
6889 The action to take when EOF is encountered on the secondary input; it accepts
6890 one of the following values:
6894 Repeat the last frame (the default).
6898 Pass the main input through.
6902 Set when the expressions for @option{x}, and @option{y} are evaluated.
6904 It accepts the following values:
6907 only evaluate expressions once during the filter initialization or
6908 when a command is processed
6911 evaluate expressions for each incoming frame
6914 Default value is @samp{frame}.
6917 If set to 1, force the output to terminate when the shortest input
6918 terminates. Default value is 0.
6921 Set the format for the output video.
6923 It accepts the following values:
6938 Default value is @samp{yuv420}.
6940 @item rgb @emph{(deprecated)}
6941 If set to 1, force the filter to accept inputs in the RGB
6942 color space. Default value is 0. This option is deprecated, use
6943 @option{format} instead.
6946 If set to 1, force the filter to draw the last overlay frame over the
6947 main input until the end of the stream. A value of 0 disables this
6948 behavior. Default value is 1.
6951 The @option{x}, and @option{y} expressions can contain the following
6957 The main input width and height.
6961 The overlay input width and height.
6965 The computed values for @var{x} and @var{y}. They are evaluated for
6970 horizontal and vertical chroma subsample values of the output
6971 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6975 the number of input frame, starting from 0
6978 the position in the file of the input frame, NAN if unknown
6981 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6985 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6986 when evaluation is done @emph{per frame}, and will evaluate to NAN
6987 when @option{eval} is set to @samp{init}.
6989 Be aware that frames are taken from each input video in timestamp
6990 order, hence, if their initial timestamps differ, it is a good idea
6991 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6992 have them begin in the same zero timestamp, as the example for
6993 the @var{movie} filter does.
6995 You can chain together more overlays but you should test the
6996 efficiency of such approach.
6998 @subsection Commands
7000 This filter supports the following commands:
7004 Modify the x and y of the overlay input.
7005 The command accepts the same syntax of the corresponding option.
7007 If the specified expression is not valid, it is kept at its current
7011 @subsection Examples
7015 Draw the overlay at 10 pixels from the bottom right corner of the main
7018 overlay=main_w-overlay_w-10:main_h-overlay_h-10
7021 Using named options the example above becomes:
7023 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
7027 Insert a transparent PNG logo in the bottom left corner of the input,
7028 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
7030 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
7034 Insert 2 different transparent PNG logos (second logo on bottom
7035 right corner) using the @command{ffmpeg} tool:
7037 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
7041 Add a transparent color layer on top of the main video; @code{WxH}
7042 must specify the size of the main input to the overlay filter:
7044 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
7048 Play an original video and a filtered version (here with the deshake
7049 filter) side by side using the @command{ffplay} tool:
7051 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
7054 The above command is the same as:
7056 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
7060 Make a sliding overlay appearing from the left to the right top part of the
7061 screen starting since time 2:
7063 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
7067 Compose output by putting two input videos side to side:
7069 ffmpeg -i left.avi -i right.avi -filter_complex "
7070 nullsrc=size=200x100 [background];
7071 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
7072 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
7073 [background][left] overlay=shortest=1 [background+left];
7074 [background+left][right] overlay=shortest=1:x=100 [left+right]
7079 Mask 10-20 seconds of a video by applying the delogo filter to a section
7081 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
7082 -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]'
7087 Chain several overlays in cascade:
7089 nullsrc=s=200x200 [bg];
7090 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
7091 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
7092 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
7093 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
7094 [in3] null, [mid2] overlay=100:100 [out0]
7101 Apply Overcomplete Wavelet denoiser.
7103 The filter accepts the following options:
7109 Larger depth values will denoise lower frequency components more, but
7110 slow down filtering.
7112 Must be an int in the range 8-16, default is @code{8}.
7114 @item luma_strength, ls
7117 Must be a double value in the range 0-1000, default is @code{1.0}.
7119 @item chroma_strength, cs
7120 Set chroma strength.
7122 Must be a double value in the range 0-1000, default is @code{1.0}.
7127 Add paddings to the input image, and place the original input at the
7128 provided @var{x}, @var{y} coordinates.
7130 It accepts the following parameters:
7135 Specify an expression for the size of the output image with the
7136 paddings added. If the value for @var{width} or @var{height} is 0, the
7137 corresponding input size is used for the output.
7139 The @var{width} expression can reference the value set by the
7140 @var{height} expression, and vice versa.
7142 The default value of @var{width} and @var{height} is 0.
7146 Specify the offsets to place the input image at within the padded area,
7147 with respect to the top/left border of the output image.
7149 The @var{x} expression can reference the value set by the @var{y}
7150 expression, and vice versa.
7152 The default value of @var{x} and @var{y} is 0.
7155 Specify the color of the padded area. For the syntax of this option,
7156 check the "Color" section in the ffmpeg-utils manual.
7158 The default value of @var{color} is "black".
7161 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
7162 options are expressions containing the following constants:
7167 The input video width and height.
7171 These are the same as @var{in_w} and @var{in_h}.
7175 The output width and height (the size of the padded area), as
7176 specified by the @var{width} and @var{height} expressions.
7180 These are the same as @var{out_w} and @var{out_h}.
7184 The x and y offsets as specified by the @var{x} and @var{y}
7185 expressions, or NAN if not yet specified.
7188 same as @var{iw} / @var{ih}
7191 input sample aspect ratio
7194 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
7198 The horizontal and vertical chroma subsample values. For example for the
7199 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7202 @subsection Examples
7206 Add paddings with the color "violet" to the input video. The output video
7207 size is 640x480, and the top-left corner of the input video is placed at
7210 pad=640:480:0:40:violet
7213 The example above is equivalent to the following command:
7215 pad=width=640:height=480:x=0:y=40:color=violet
7219 Pad the input to get an output with dimensions increased by 3/2,
7220 and put the input video at the center of the padded area:
7222 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
7226 Pad the input to get a squared output with size equal to the maximum
7227 value between the input width and height, and put the input video at
7228 the center of the padded area:
7230 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
7234 Pad the input to get a final w/h ratio of 16:9:
7236 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
7240 In case of anamorphic video, in order to set the output display aspect
7241 correctly, it is necessary to use @var{sar} in the expression,
7242 according to the relation:
7244 (ih * X / ih) * sar = output_dar
7245 X = output_dar / sar
7248 Thus the previous example needs to be modified to:
7250 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
7254 Double the output size and put the input video in the bottom-right
7255 corner of the output padded area:
7257 pad="2*iw:2*ih:ow-iw:oh-ih"
7264 Generate one palette for a whole video stream.
7266 It accepts the following options:
7270 Set the maximum number of colors to quantize in the palette.
7271 Note: the palette will still contain 256 colors; the unused palette entries
7274 @item reserve_transparent
7275 Create a palette of 255 colors maximum and reserve the last one for
7276 transparency. Reserving the transparency color is useful for GIF optimization.
7277 If not set, the maximum of colors in the palette will be 256. You probably want
7278 to disable this option for a standalone image.
7282 Set statistics mode.
7284 It accepts the following values:
7287 Compute full frame histograms.
7289 Compute histograms only for the part that differs from previous frame. This
7290 might be relevant to give more importance to the moving part of your input if
7291 the background is static.
7294 Default value is @var{full}.
7297 The filter also exports the frame metadata @code{lavfi.color_quant_ratio}
7298 (@code{nb_color_in / nb_color_out}) which you can use to evaluate the degree of
7299 color quantization of the palette. This information is also visible at
7300 @var{info} logging level.
7302 @subsection Examples
7306 Generate a representative palette of a given video using @command{ffmpeg}:
7308 ffmpeg -i input.mkv -vf palettegen palette.png
7314 Use a palette to downsample an input video stream.
7316 The filter takes two inputs: one video stream and a palette. The palette must
7317 be a 256 pixels image.
7319 It accepts the following options:
7323 Select dithering mode. Available algorithms are:
7326 Ordered 8x8 bayer dithering (deterministic)
7328 Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
7329 Note: this dithering is sometimes considered "wrong" and is included as a
7331 @item floyd_steinberg
7332 Floyd and Steingberg dithering (error diffusion)
7334 Frankie Sierra dithering v2 (error diffusion)
7336 Frankie Sierra dithering v2 "Lite" (error diffusion)
7339 Default is @var{sierra2_4a}.
7342 When @var{bayer} dithering is selected, this option defines the scale of the
7343 pattern (how much the crosshatch pattern is visible). A low value means more
7344 visible pattern for less banding, and higher value means less visible pattern
7345 at the cost of more banding.
7347 The option must be an integer value in the range [0,5]. Default is @var{2}.
7350 If set, define the zone to process
7354 Only the changing rectangle will be reprocessed. This is similar to GIF
7355 cropping/offsetting compression mechanism. This option can be useful for speed
7356 if only a part of the image is changing, and has use cases such as limiting the
7357 scope of the error diffusal @option{dither} to the rectangle that bounds the
7358 moving scene (it leads to more deterministic output if the scene doesn't change
7359 much, and as a result less moving noise and better GIF compression).
7362 Default is @var{none}.
7365 @subsection Examples
7369 Use a palette (generated for example with @ref{palettegen}) to encode a GIF
7370 using @command{ffmpeg}:
7372 ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
7376 @section perspective
7378 Correct perspective of video not recorded perpendicular to the screen.
7380 A description of the accepted parameters follows.
7391 Set coordinates expression for top left, top right, bottom left and bottom right corners.
7392 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
7393 If the @code{sense} option is set to @code{source}, then the specified points will be sent
7394 to the corners of the destination. If the @code{sense} option is set to @code{destination},
7395 then the corners of the source will be sent to the specified coordinates.
7397 The expressions can use the following variables:
7402 the width and height of video frame.
7406 Set interpolation for perspective correction.
7408 It accepts the following values:
7414 Default value is @samp{linear}.
7417 Set interpretation of coordinate options.
7419 It accepts the following values:
7423 Send point in the source specified by the given coordinates to
7424 the corners of the destination.
7426 @item 1, destination
7428 Send the corners of the source to the point in the destination specified
7429 by the given coordinates.
7431 Default value is @samp{source}.
7437 Delay interlaced video by one field time so that the field order changes.
7439 The intended use is to fix PAL movies that have been captured with the
7440 opposite field order to the film-to-video transfer.
7442 A description of the accepted parameters follows.
7448 It accepts the following values:
7451 Capture field order top-first, transfer bottom-first.
7452 Filter will delay the bottom field.
7455 Capture field order bottom-first, transfer top-first.
7456 Filter will delay the top field.
7459 Capture and transfer with the same field order. This mode only exists
7460 for the documentation of the other options to refer to, but if you
7461 actually select it, the filter will faithfully do nothing.
7464 Capture field order determined automatically by field flags, transfer
7466 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
7467 basis using field flags. If no field information is available,
7468 then this works just like @samp{u}.
7471 Capture unknown or varying, transfer opposite.
7472 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
7473 analyzing the images and selecting the alternative that produces best
7474 match between the fields.
7477 Capture top-first, transfer unknown or varying.
7478 Filter selects among @samp{t} and @samp{p} using image analysis.
7481 Capture bottom-first, transfer unknown or varying.
7482 Filter selects among @samp{b} and @samp{p} using image analysis.
7485 Capture determined by field flags, transfer unknown or varying.
7486 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
7487 image analysis. If no field information is available, then this works just
7488 like @samp{U}. This is the default mode.
7491 Both capture and transfer unknown or varying.
7492 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
7496 @section pixdesctest
7498 Pixel format descriptor test filter, mainly useful for internal
7499 testing. The output video should be equal to the input video.
7503 format=monow, pixdesctest
7506 can be used to test the monowhite pixel format descriptor definition.
7510 Enable the specified chain of postprocessing subfilters using libpostproc. This
7511 library should be automatically selected with a GPL build (@code{--enable-gpl}).
7512 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
7513 Each subfilter and some options have a short and a long name that can be used
7514 interchangeably, i.e. dr/dering are the same.
7516 The filters accept the following options:
7520 Set postprocessing subfilters string.
7523 All subfilters share common options to determine their scope:
7527 Honor the quality commands for this subfilter.
7530 Do chrominance filtering, too (default).
7533 Do luminance filtering only (no chrominance).
7536 Do chrominance filtering only (no luminance).
7539 These options can be appended after the subfilter name, separated by a '|'.
7541 Available subfilters are:
7544 @item hb/hdeblock[|difference[|flatness]]
7545 Horizontal deblocking filter
7548 Difference factor where higher values mean more deblocking (default: @code{32}).
7550 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7553 @item vb/vdeblock[|difference[|flatness]]
7554 Vertical deblocking filter
7557 Difference factor where higher values mean more deblocking (default: @code{32}).
7559 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7562 @item ha/hadeblock[|difference[|flatness]]
7563 Accurate horizontal deblocking filter
7566 Difference factor where higher values mean more deblocking (default: @code{32}).
7568 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7571 @item va/vadeblock[|difference[|flatness]]
7572 Accurate vertical deblocking filter
7575 Difference factor where higher values mean more deblocking (default: @code{32}).
7577 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7581 The horizontal and vertical deblocking filters share the difference and
7582 flatness values so you cannot set different horizontal and vertical
7587 Experimental horizontal deblocking filter
7590 Experimental vertical deblocking filter
7595 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
7598 larger -> stronger filtering
7600 larger -> stronger filtering
7602 larger -> stronger filtering
7605 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
7608 Stretch luminance to @code{0-255}.
7611 @item lb/linblenddeint
7612 Linear blend deinterlacing filter that deinterlaces the given block by
7613 filtering all lines with a @code{(1 2 1)} filter.
7615 @item li/linipoldeint
7616 Linear interpolating deinterlacing filter that deinterlaces the given block by
7617 linearly interpolating every second line.
7619 @item ci/cubicipoldeint
7620 Cubic interpolating deinterlacing filter deinterlaces the given block by
7621 cubically interpolating every second line.
7623 @item md/mediandeint
7624 Median deinterlacing filter that deinterlaces the given block by applying a
7625 median filter to every second line.
7627 @item fd/ffmpegdeint
7628 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
7629 second line with a @code{(-1 4 2 4 -1)} filter.
7632 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
7633 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
7635 @item fq/forceQuant[|quantizer]
7636 Overrides the quantizer table from the input with the constant quantizer you
7644 Default pp filter combination (@code{hb|a,vb|a,dr|a})
7647 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
7650 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
7653 @subsection Examples
7657 Apply horizontal and vertical deblocking, deringing and automatic
7658 brightness/contrast:
7664 Apply default filters without brightness/contrast correction:
7670 Apply default filters and temporal denoiser:
7672 pp=default/tmpnoise|1|2|3
7676 Apply deblocking on luminance only, and switch vertical deblocking on or off
7677 automatically depending on available CPU time:
7684 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
7685 similar to spp = 6 with 7 point DCT, where only the center sample is
7688 The filter accepts the following options:
7692 Force a constant quantization parameter. It accepts an integer in range
7693 0 to 63. If not set, the filter will use the QP from the video stream
7697 Set thresholding mode. Available modes are:
7701 Set hard thresholding.
7703 Set soft thresholding (better de-ringing effect, but likely blurrier).
7705 Set medium thresholding (good results, default).
7711 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
7712 Ratio) between two input videos.
7714 This filter takes in input two input videos, the first input is
7715 considered the "main" source and is passed unchanged to the
7716 output. The second input is used as a "reference" video for computing
7719 Both video inputs must have the same resolution and pixel format for
7720 this filter to work correctly. Also it assumes that both inputs
7721 have the same number of frames, which are compared one by one.
7723 The obtained average PSNR is printed through the logging system.
7725 The filter stores the accumulated MSE (mean squared error) of each
7726 frame, and at the end of the processing it is averaged across all frames
7727 equally, and the following formula is applied to obtain the PSNR:
7730 PSNR = 10*log10(MAX^2/MSE)
7733 Where MAX is the average of the maximum values of each component of the
7736 The description of the accepted parameters follows.
7740 If specified the filter will use the named file to save the PSNR of
7741 each individual frame.
7744 The file printed if @var{stats_file} is selected, contains a sequence of
7745 key/value pairs of the form @var{key}:@var{value} for each compared
7748 A description of each shown parameter follows:
7752 sequential number of the input frame, starting from 1
7755 Mean Square Error pixel-by-pixel average difference of the compared
7756 frames, averaged over all the image components.
7758 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
7759 Mean Square Error pixel-by-pixel average difference of the compared
7760 frames for the component specified by the suffix.
7762 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
7763 Peak Signal to Noise ratio of the compared frames for the component
7764 specified by the suffix.
7769 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
7770 [main][ref] psnr="stats_file=stats.log" [out]
7773 On this example the input file being processed is compared with the
7774 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
7775 is stored in @file{stats.log}.
7780 Pulldown reversal (inverse telecine) filter, capable of handling mixed
7781 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
7784 The pullup filter is designed to take advantage of future context in making
7785 its decisions. This filter is stateless in the sense that it does not lock
7786 onto a pattern to follow, but it instead looks forward to the following
7787 fields in order to identify matches and rebuild progressive frames.
7789 To produce content with an even framerate, insert the fps filter after
7790 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
7791 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
7793 The filter accepts the following options:
7800 These options set the amount of "junk" to ignore at the left, right, top, and
7801 bottom of the image, respectively. Left and right are in units of 8 pixels,
7802 while top and bottom are in units of 2 lines.
7803 The default is 8 pixels on each side.
7806 Set the strict breaks. Setting this option to 1 will reduce the chances of
7807 filter generating an occasional mismatched frame, but it may also cause an
7808 excessive number of frames to be dropped during high motion sequences.
7809 Conversely, setting it to -1 will make filter match fields more easily.
7810 This may help processing of video where there is slight blurring between
7811 the fields, but may also cause there to be interlaced frames in the output.
7812 Default value is @code{0}.
7815 Set the metric plane to use. It accepts the following values:
7821 Use chroma blue plane.
7824 Use chroma red plane.
7827 This option may be set to use chroma plane instead of the default luma plane
7828 for doing filter's computations. This may improve accuracy on very clean
7829 source material, but more likely will decrease accuracy, especially if there
7830 is chroma noise (rainbow effect) or any grayscale video.
7831 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
7832 load and make pullup usable in realtime on slow machines.
7835 For best results (without duplicated frames in the output file) it is
7836 necessary to change the output frame rate. For example, to inverse
7837 telecine NTSC input:
7839 ffmpeg -i input -vf pullup -r 24000/1001 ...
7844 Change video quantization parameters (QP).
7846 The filter accepts the following option:
7850 Set expression for quantization parameter.
7853 The expression is evaluated through the eval API and can contain, among others,
7854 the following constants:
7858 1 if index is not 129, 0 otherwise.
7861 Sequentional index starting from -129 to 128.
7864 @subsection Examples
7876 Suppress a TV station logo, using an image file to determine which
7877 pixels comprise the logo. It works by filling in the pixels that
7878 comprise the logo with neighboring pixels.
7880 The filter accepts the following options:
7884 Set the filter bitmap file, which can be any image format supported by
7885 libavformat. The width and height of the image file must match those of the
7886 video stream being processed.
7889 Pixels in the provided bitmap image with a value of zero are not
7890 considered part of the logo, non-zero pixels are considered part of
7891 the logo. If you use white (255) for the logo and black (0) for the
7892 rest, you will be safe. For making the filter bitmap, it is
7893 recommended to take a screen capture of a black frame with the logo
7894 visible, and then using a threshold filter followed by the erode
7895 filter once or twice.
7897 If needed, little splotches can be fixed manually. Remember that if
7898 logo pixels are not covered, the filter quality will be much
7899 reduced. Marking too many pixels as part of the logo does not hurt as
7900 much, but it will increase the amount of blurring needed to cover over
7901 the image and will destroy more information than necessary, and extra
7902 pixels will slow things down on a large logo.
7904 @section repeatfields
7906 This filter uses the repeat_field flag from the Video ES headers and hard repeats
7907 fields based on its value.
7911 Rotate video by an arbitrary angle expressed in radians.
7913 The filter accepts the following options:
7915 A description of the optional parameters follows.
7918 Set an expression for the angle by which to rotate the input video
7919 clockwise, expressed as a number of radians. A negative value will
7920 result in a counter-clockwise rotation. By default it is set to "0".
7922 This expression is evaluated for each frame.
7925 Set the output width expression, default value is "iw".
7926 This expression is evaluated just once during configuration.
7929 Set the output height expression, default value is "ih".
7930 This expression is evaluated just once during configuration.
7933 Enable bilinear interpolation if set to 1, a value of 0 disables
7934 it. Default value is 1.
7937 Set the color used to fill the output area not covered by the rotated
7938 image. For the general syntax of this option, check the "Color" section in the
7939 ffmpeg-utils manual. If the special value "none" is selected then no
7940 background is printed (useful for example if the background is never shown).
7942 Default value is "black".
7945 The expressions for the angle and the output size can contain the
7946 following constants and functions:
7950 sequential number of the input frame, starting from 0. It is always NAN
7951 before the first frame is filtered.
7954 time in seconds of the input frame, it is set to 0 when the filter is
7955 configured. It is always NAN before the first frame is filtered.
7959 horizontal and vertical chroma subsample values. For example for the
7960 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7964 the input video width and height
7968 the output width and height, that is the size of the padded area as
7969 specified by the @var{width} and @var{height} expressions
7973 the minimal width/height required for completely containing the input
7974 video rotated by @var{a} radians.
7976 These are only available when computing the @option{out_w} and
7977 @option{out_h} expressions.
7980 @subsection Examples
7984 Rotate the input by PI/6 radians clockwise:
7990 Rotate the input by PI/6 radians counter-clockwise:
7996 Rotate the input by 45 degrees clockwise:
8002 Apply a constant rotation with period T, starting from an angle of PI/3:
8004 rotate=PI/3+2*PI*t/T
8008 Make the input video rotation oscillating with a period of T
8009 seconds and an amplitude of A radians:
8011 rotate=A*sin(2*PI/T*t)
8015 Rotate the video, output size is chosen so that the whole rotating
8016 input video is always completely contained in the output:
8018 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
8022 Rotate the video, reduce the output size so that no background is ever
8025 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
8029 @subsection Commands
8031 The filter supports the following commands:
8035 Set the angle expression.
8036 The command accepts the same syntax of the corresponding option.
8038 If the specified expression is not valid, it is kept at its current
8044 Apply Shape Adaptive Blur.
8046 The filter accepts the following options:
8049 @item luma_radius, lr
8050 Set luma blur filter strength, must be a value in range 0.1-4.0, default
8051 value is 1.0. A greater value will result in a more blurred image, and
8052 in slower processing.
8054 @item luma_pre_filter_radius, lpfr
8055 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
8058 @item luma_strength, ls
8059 Set luma maximum difference between pixels to still be considered, must
8060 be a value in the 0.1-100.0 range, default value is 1.0.
8062 @item chroma_radius, cr
8063 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
8064 greater value will result in a more blurred image, and in slower
8067 @item chroma_pre_filter_radius, cpfr
8068 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
8070 @item chroma_strength, cs
8071 Set chroma maximum difference between pixels to still be considered,
8072 must be a value in the 0.1-100.0 range.
8075 Each chroma option value, if not explicitly specified, is set to the
8076 corresponding luma option value.
8081 Scale (resize) the input video, using the libswscale library.
8083 The scale filter forces the output display aspect ratio to be the same
8084 of the input, by changing the output sample aspect ratio.
8086 If the input image format is different from the format requested by
8087 the next filter, the scale filter will convert the input to the
8091 The filter accepts the following options, or any of the options
8092 supported by the libswscale scaler.
8094 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
8095 the complete list of scaler options.
8100 Set the output video dimension expression. Default value is the input
8103 If the value is 0, the input width is used for the output.
8105 If one of the values is -1, the scale filter will use a value that
8106 maintains the aspect ratio of the input image, calculated from the
8107 other specified dimension. If both of them are -1, the input size is
8110 If one of the values is -n with n > 1, the scale filter will also use a value
8111 that maintains the aspect ratio of the input image, calculated from the other
8112 specified dimension. After that it will, however, make sure that the calculated
8113 dimension is divisible by n and adjust the value if necessary.
8115 See below for the list of accepted constants for use in the dimension
8119 Set the interlacing mode. It accepts the following values:
8123 Force interlaced aware scaling.
8126 Do not apply interlaced scaling.
8129 Select interlaced aware scaling depending on whether the source frames
8130 are flagged as interlaced or not.
8133 Default value is @samp{0}.
8136 Set libswscale scaling flags. See
8137 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
8138 complete list of values. If not explicitly specified the filter applies
8142 Set the video size. For the syntax of this option, check the
8143 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
8145 @item in_color_matrix
8146 @item out_color_matrix
8147 Set in/output YCbCr color space type.
8149 This allows the autodetected value to be overridden as well as allows forcing
8150 a specific value used for the output and encoder.
8152 If not specified, the color space type depends on the pixel format.
8158 Choose automatically.
8161 Format conforming to International Telecommunication Union (ITU)
8162 Recommendation BT.709.
8165 Set color space conforming to the United States Federal Communications
8166 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
8169 Set color space conforming to:
8173 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
8176 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
8179 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
8184 Set color space conforming to SMPTE ST 240:1999.
8189 Set in/output YCbCr sample range.
8191 This allows the autodetected value to be overridden as well as allows forcing
8192 a specific value used for the output and encoder. If not specified, the
8193 range depends on the pixel format. Possible values:
8197 Choose automatically.
8200 Set full range (0-255 in case of 8-bit luma).
8203 Set "MPEG" range (16-235 in case of 8-bit luma).
8206 @item force_original_aspect_ratio
8207 Enable decreasing or increasing output video width or height if necessary to
8208 keep the original aspect ratio. Possible values:
8212 Scale the video as specified and disable this feature.
8215 The output video dimensions will automatically be decreased if needed.
8218 The output video dimensions will automatically be increased if needed.
8222 One useful instance of this option is that when you know a specific device's
8223 maximum allowed resolution, you can use this to limit the output video to
8224 that, while retaining the aspect ratio. For example, device A allows
8225 1280x720 playback, and your video is 1920x800. Using this option (set it to
8226 decrease) and specifying 1280x720 to the command line makes the output
8229 Please note that this is a different thing than specifying -1 for @option{w}
8230 or @option{h}, you still need to specify the output resolution for this option
8235 The values of the @option{w} and @option{h} options are expressions
8236 containing the following constants:
8241 The input width and height
8245 These are the same as @var{in_w} and @var{in_h}.
8249 The output (scaled) width and height
8253 These are the same as @var{out_w} and @var{out_h}
8256 The same as @var{iw} / @var{ih}
8259 input sample aspect ratio
8262 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
8266 horizontal and vertical input chroma subsample values. For example for the
8267 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
8271 horizontal and vertical output chroma subsample values. For example for the
8272 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
8275 @subsection Examples
8279 Scale the input video to a size of 200x100
8284 This is equivalent to:
8295 Specify a size abbreviation for the output size:
8300 which can also be written as:
8306 Scale the input to 2x:
8312 The above is the same as:
8318 Scale the input to 2x with forced interlaced scaling:
8320 scale=2*iw:2*ih:interl=1
8324 Scale the input to half size:
8330 Increase the width, and set the height to the same size:
8343 Increase the height, and set the width to 3/2 of the height:
8345 scale=w=3/2*oh:h=3/5*ih
8349 Increase the size, making the size a multiple of the chroma
8352 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
8356 Increase the width to a maximum of 500 pixels,
8357 keeping the same aspect ratio as the input:
8359 scale=w='min(500\, iw*3/2):h=-1'
8363 @section separatefields
8365 The @code{separatefields} takes a frame-based video input and splits
8366 each frame into its components fields, producing a new half height clip
8367 with twice the frame rate and twice the frame count.
8369 This filter use field-dominance information in frame to decide which
8370 of each pair of fields to place first in the output.
8371 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
8373 @section setdar, setsar
8375 The @code{setdar} filter sets the Display Aspect Ratio for the filter
8378 This is done by changing the specified Sample (aka Pixel) Aspect
8379 Ratio, according to the following equation:
8381 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
8384 Keep in mind that the @code{setdar} filter does not modify the pixel
8385 dimensions of the video frame. Also, the display aspect ratio set by
8386 this filter may be changed by later filters in the filterchain,
8387 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
8390 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
8391 the filter output video.
8393 Note that as a consequence of the application of this filter, the
8394 output display aspect ratio will change according to the equation
8397 Keep in mind that the sample aspect ratio set by the @code{setsar}
8398 filter may be changed by later filters in the filterchain, e.g. if
8399 another "setsar" or a "setdar" filter is applied.
8401 It accepts the following parameters:
8404 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
8405 Set the aspect ratio used by the filter.
8407 The parameter can be a floating point number string, an expression, or
8408 a string of the form @var{num}:@var{den}, where @var{num} and
8409 @var{den} are the numerator and denominator of the aspect ratio. If
8410 the parameter is not specified, it is assumed the value "0".
8411 In case the form "@var{num}:@var{den}" is used, the @code{:} character
8415 Set the maximum integer value to use for expressing numerator and
8416 denominator when reducing the expressed aspect ratio to a rational.
8417 Default value is @code{100}.
8421 The parameter @var{sar} is an expression containing
8422 the following constants:
8426 These are approximated values for the mathematical constants e
8427 (Euler's number), pi (Greek pi), and phi (the golden ratio).
8430 The input width and height.
8433 These are the same as @var{w} / @var{h}.
8436 The input sample aspect ratio.
8439 The input display aspect ratio. It is the same as
8440 (@var{w} / @var{h}) * @var{sar}.
8443 Horizontal and vertical chroma subsample values. For example, for the
8444 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
8447 @subsection Examples
8452 To change the display aspect ratio to 16:9, specify one of the following:
8460 To change the sample aspect ratio to 10:11, specify:
8466 To set a display aspect ratio of 16:9, and specify a maximum integer value of
8467 1000 in the aspect ratio reduction, use the command:
8469 setdar=ratio=16/9:max=1000
8477 Force field for the output video frame.
8479 The @code{setfield} filter marks the interlace type field for the
8480 output frames. It does not change the input frame, but only sets the
8481 corresponding property, which affects how the frame is treated by
8482 following filters (e.g. @code{fieldorder} or @code{yadif}).
8484 The filter accepts the following options:
8489 Available values are:
8493 Keep the same field property.
8496 Mark the frame as bottom-field-first.
8499 Mark the frame as top-field-first.
8502 Mark the frame as progressive.
8508 Show a line containing various information for each input video frame.
8509 The input video is not modified.
8511 The shown line contains a sequence of key/value pairs of the form
8512 @var{key}:@var{value}.
8514 The following values are shown in the output:
8518 The (sequential) number of the input frame, starting from 0.
8521 The Presentation TimeStamp of the input frame, expressed as a number of
8522 time base units. The time base unit depends on the filter input pad.
8525 The Presentation TimeStamp of the input frame, expressed as a number of
8529 The position of the frame in the input stream, or -1 if this information is
8530 unavailable and/or meaningless (for example in case of synthetic video).
8533 The pixel format name.
8536 The sample aspect ratio of the input frame, expressed in the form
8537 @var{num}/@var{den}.
8540 The size of the input frame. For the syntax of this option, check the
8541 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
8544 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
8545 for bottom field first).
8548 This is 1 if the frame is a key frame, 0 otherwise.
8551 The picture type of the input frame ("I" for an I-frame, "P" for a
8552 P-frame, "B" for a B-frame, or "?" for an unknown type).
8553 Also refer to the documentation of the @code{AVPictureType} enum and of
8554 the @code{av_get_picture_type_char} function defined in
8555 @file{libavutil/avutil.h}.
8558 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
8560 @item plane_checksum
8561 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
8562 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
8565 @section showpalette
8567 Displays the 256 colors palette of each frame. This filter is only relevant for
8568 @var{pal8} pixel format frames.
8570 It accepts the following option:
8574 Set the size of the box used to represent one palette color entry. Default is
8575 @code{30} (for a @code{30x30} pixel box).
8578 @section shuffleplanes
8580 Reorder and/or duplicate video planes.
8582 It accepts the following parameters:
8587 The index of the input plane to be used as the first output plane.
8590 The index of the input plane to be used as the second output plane.
8593 The index of the input plane to be used as the third output plane.
8596 The index of the input plane to be used as the fourth output plane.
8600 The first plane has the index 0. The default is to keep the input unchanged.
8602 Swap the second and third planes of the input:
8604 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
8607 @section signalstats
8608 Evaluate various visual metrics that assist in determining issues associated
8609 with the digitization of analog video media.
8611 By default the filter will log these metadata values:
8615 Display the minimal Y value contained within the input frame. Expressed in
8619 Display the Y value at the 10% percentile within the input frame. Expressed in
8623 Display the average Y value within the input frame. Expressed in range of
8627 Display the Y value at the 90% percentile within the input frame. Expressed in
8631 Display the maximum Y value contained within the input frame. Expressed in
8635 Display the minimal U value contained within the input frame. Expressed in
8639 Display the U value at the 10% percentile within the input frame. Expressed in
8643 Display the average U value within the input frame. Expressed in range of
8647 Display the U value at the 90% percentile within the input frame. Expressed in
8651 Display the maximum U value contained within the input frame. Expressed in
8655 Display the minimal V value contained within the input frame. Expressed in
8659 Display the V value at the 10% percentile within the input frame. Expressed in
8663 Display the average V value within the input frame. Expressed in range of
8667 Display the V value at the 90% percentile within the input frame. Expressed in
8671 Display the maximum V value contained within the input frame. Expressed in
8675 Display the minimal saturation value contained within the input frame.
8676 Expressed in range of [0-~181.02].
8679 Display the saturation value at the 10% percentile within the input frame.
8680 Expressed in range of [0-~181.02].
8683 Display the average saturation value within the input frame. Expressed in range
8687 Display the saturation value at the 90% percentile within the input frame.
8688 Expressed in range of [0-~181.02].
8691 Display the maximum saturation value contained within the input frame.
8692 Expressed in range of [0-~181.02].
8695 Display the median value for hue within the input frame. Expressed in range of
8699 Display the average value for hue within the input frame. Expressed in range of
8703 Display the average of sample value difference between all values of the Y
8704 plane in the current frame and corresponding values of the previous input frame.
8705 Expressed in range of [0-255].
8708 Display the average of sample value difference between all values of the U
8709 plane in the current frame and corresponding values of the previous input frame.
8710 Expressed in range of [0-255].
8713 Display the average of sample value difference between all values of the V
8714 plane in the current frame and corresponding values of the previous input frame.
8715 Expressed in range of [0-255].
8718 The filter accepts the following options:
8724 @option{stat} specify an additional form of image analysis.
8725 @option{out} output video with the specified type of pixel highlighted.
8727 Both options accept the following values:
8731 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
8732 unlike the neighboring pixels of the same field. Examples of temporal outliers
8733 include the results of video dropouts, head clogs, or tape tracking issues.
8736 Identify @var{vertical line repetition}. Vertical line repetition includes
8737 similar rows of pixels within a frame. In born-digital video vertical line
8738 repetition is common, but this pattern is uncommon in video digitized from an
8739 analog source. When it occurs in video that results from the digitization of an
8740 analog source it can indicate concealment from a dropout compensator.
8743 Identify pixels that fall outside of legal broadcast range.
8747 Set the highlight color for the @option{out} option. The default color is
8751 @subsection Examples
8755 Output data of various video metrics:
8757 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
8761 Output specific data about the minimum and maximum values of the Y plane per frame:
8763 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
8767 Playback video while highlighting pixels that are outside of broadcast range in red.
8769 ffplay example.mov -vf signalstats="out=brng:color=red"
8773 Playback video with signalstats metadata drawn over the frame.
8775 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
8778 The contents of signalstat_drawtext.txt used in the command are:
8781 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
8782 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
8783 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
8784 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
8792 Blur the input video without impacting the outlines.
8794 It accepts the following options:
8797 @item luma_radius, lr
8798 Set the luma radius. The option value must be a float number in
8799 the range [0.1,5.0] that specifies the variance of the gaussian filter
8800 used to blur the image (slower if larger). Default value is 1.0.
8802 @item luma_strength, ls
8803 Set the luma strength. The option value must be a float number
8804 in the range [-1.0,1.0] that configures the blurring. A value included
8805 in [0.0,1.0] will blur the image whereas a value included in
8806 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8808 @item luma_threshold, lt
8809 Set the luma threshold used as a coefficient to determine
8810 whether a pixel should be blurred or not. The option value must be an
8811 integer in the range [-30,30]. A value of 0 will filter all the image,
8812 a value included in [0,30] will filter flat areas and a value included
8813 in [-30,0] will filter edges. Default value is 0.
8815 @item chroma_radius, cr
8816 Set the chroma radius. The option value must be a float number in
8817 the range [0.1,5.0] that specifies the variance of the gaussian filter
8818 used to blur the image (slower if larger). Default value is 1.0.
8820 @item chroma_strength, cs
8821 Set the chroma strength. The option value must be a float number
8822 in the range [-1.0,1.0] that configures the blurring. A value included
8823 in [0.0,1.0] will blur the image whereas a value included in
8824 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8826 @item chroma_threshold, ct
8827 Set the chroma threshold used as a coefficient to determine
8828 whether a pixel should be blurred or not. The option value must be an
8829 integer in the range [-30,30]. A value of 0 will filter all the image,
8830 a value included in [0,30] will filter flat areas and a value included
8831 in [-30,0] will filter edges. Default value is 0.
8834 If a chroma option is not explicitly set, the corresponding luma value
8839 Obtain the SSIM (Structural SImilarity Metric) between two input videos.
8841 This filter takes in input two input videos, the first input is
8842 considered the "main" source and is passed unchanged to the
8843 output. The second input is used as a "reference" video for computing
8846 Both video inputs must have the same resolution and pixel format for
8847 this filter to work correctly. Also it assumes that both inputs
8848 have the same number of frames, which are compared one by one.
8850 The filter stores the calculated SSIM of each frame.
8852 The description of the accepted parameters follows.
8856 If specified the filter will use the named file to save the PSNR of
8857 each individual frame.
8860 The file printed if @var{stats_file} is selected, contains a sequence of
8861 key/value pairs of the form @var{key}:@var{value} for each compared
8864 A description of each shown parameter follows:
8868 sequential number of the input frame, starting from 1
8870 @item Y, U, V, R, G, B
8871 SSIM of the compared frames for the component specified by the suffix.
8874 SSIM of the compared frames for the whole frame.
8877 Same as above but in dB representation.
8882 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
8883 [main][ref] ssim="stats_file=stats.log" [out]
8886 On this example the input file being processed is compared with the
8887 reference file @file{ref_movie.mpg}. The SSIM of each individual frame
8888 is stored in @file{stats.log}.
8890 Another example with both psnr and ssim at same time:
8892 ffmpeg -i main.mpg -i ref.mpg -lavfi "ssim;[0:v][1:v]psnr" -f null -
8897 Convert between different stereoscopic image formats.
8899 The filters accept the following options:
8903 Set stereoscopic image format of input.
8905 Available values for input image formats are:
8908 side by side parallel (left eye left, right eye right)
8911 side by side crosseye (right eye left, left eye right)
8914 side by side parallel with half width resolution
8915 (left eye left, right eye right)
8918 side by side crosseye with half width resolution
8919 (right eye left, left eye right)
8922 above-below (left eye above, right eye below)
8925 above-below (right eye above, left eye below)
8928 above-below with half height resolution
8929 (left eye above, right eye below)
8932 above-below with half height resolution
8933 (right eye above, left eye below)
8936 alternating frames (left eye first, right eye second)
8939 alternating frames (right eye first, left eye second)
8941 Default value is @samp{sbsl}.
8945 Set stereoscopic image format of output.
8947 Available values for output image formats are all the input formats as well as:
8950 anaglyph red/blue gray
8951 (red filter on left eye, blue filter on right eye)
8954 anaglyph red/green gray
8955 (red filter on left eye, green filter on right eye)
8958 anaglyph red/cyan gray
8959 (red filter on left eye, cyan filter on right eye)
8962 anaglyph red/cyan half colored
8963 (red filter on left eye, cyan filter on right eye)
8966 anaglyph red/cyan color
8967 (red filter on left eye, cyan filter on right eye)
8970 anaglyph red/cyan color optimized with the least squares projection of dubois
8971 (red filter on left eye, cyan filter on right eye)
8974 anaglyph green/magenta gray
8975 (green filter on left eye, magenta filter on right eye)
8978 anaglyph green/magenta half colored
8979 (green filter on left eye, magenta filter on right eye)
8982 anaglyph green/magenta colored
8983 (green filter on left eye, magenta filter on right eye)
8986 anaglyph green/magenta color optimized with the least squares projection of dubois
8987 (green filter on left eye, magenta filter on right eye)
8990 anaglyph yellow/blue gray
8991 (yellow filter on left eye, blue filter on right eye)
8994 anaglyph yellow/blue half colored
8995 (yellow filter on left eye, blue filter on right eye)
8998 anaglyph yellow/blue colored
8999 (yellow filter on left eye, blue filter on right eye)
9002 anaglyph yellow/blue color optimized with the least squares projection of dubois
9003 (yellow filter on left eye, blue filter on right eye)
9006 interleaved rows (left eye has top row, right eye starts on next row)
9009 interleaved rows (right eye has top row, left eye starts on next row)
9012 mono output (left eye only)
9015 mono output (right eye only)
9018 Default value is @samp{arcd}.
9021 @subsection Examples
9025 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
9031 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
9040 Apply a simple postprocessing filter that compresses and decompresses the image
9041 at several (or - in the case of @option{quality} level @code{6} - all) shifts
9042 and average the results.
9044 The filter accepts the following options:
9048 Set quality. This option defines the number of levels for averaging. It accepts
9049 an integer in the range 0-6. If set to @code{0}, the filter will have no
9050 effect. A value of @code{6} means the higher quality. For each increment of
9051 that value the speed drops by a factor of approximately 2. Default value is
9055 Force a constant quantization parameter. If not set, the filter will use the QP
9056 from the video stream (if available).
9059 Set thresholding mode. Available modes are:
9063 Set hard thresholding (default).
9065 Set soft thresholding (better de-ringing effect, but likely blurrier).
9069 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
9070 option may cause flicker since the B-Frames have often larger QP. Default is
9071 @code{0} (not enabled).
9077 Draw subtitles on top of input video using the libass library.
9079 To enable compilation of this filter you need to configure FFmpeg with
9080 @code{--enable-libass}. This filter also requires a build with libavcodec and
9081 libavformat to convert the passed subtitles file to ASS (Advanced Substation
9082 Alpha) subtitles format.
9084 The filter accepts the following options:
9088 Set the filename of the subtitle file to read. It must be specified.
9091 Specify the size of the original video, the video for which the ASS file
9092 was composed. For the syntax of this option, check the
9093 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
9094 Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
9095 correctly scale the fonts if the aspect ratio has been changed.
9098 Set subtitles input character encoding. @code{subtitles} filter only. Only
9099 useful if not UTF-8.
9101 @item stream_index, si
9102 Set subtitles stream index. @code{subtitles} filter only.
9105 Override default style or script info parameters of the subtitles. It accepts a
9106 string containing ASS style format @code{KEY=VALUE} couples separated by ",".
9109 If the first key is not specified, it is assumed that the first value
9110 specifies the @option{filename}.
9112 For example, to render the file @file{sub.srt} on top of the input
9113 video, use the command:
9118 which is equivalent to:
9120 subtitles=filename=sub.srt
9123 To render the default subtitles stream from file @file{video.mkv}, use:
9128 To render the second subtitles stream from that file, use:
9130 subtitles=video.mkv:si=1
9133 To make the subtitles stream from @file{sub.srt} appear in transparent green
9134 @code{DejaVu Serif}, use:
9136 subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'
9141 Scale the input by 2x and smooth using the Super2xSaI (Scale and
9142 Interpolate) pixel art scaling algorithm.
9144 Useful for enlarging pixel art images without reducing sharpness.
9151 Apply telecine process to the video.
9153 This filter accepts the following options:
9162 The default value is @code{top}.
9166 A string of numbers representing the pulldown pattern you wish to apply.
9167 The default value is @code{23}.
9171 Some typical patterns:
9176 24p: 2332 (preferred)
9183 24p: 222222222223 ("Euro pulldown")
9189 Select the most representative frame in a given sequence of consecutive frames.
9191 The filter accepts the following options:
9195 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
9196 will pick one of them, and then handle the next batch of @var{n} frames until
9197 the end. Default is @code{100}.
9200 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
9201 value will result in a higher memory usage, so a high value is not recommended.
9203 @subsection Examples
9207 Extract one picture each 50 frames:
9213 Complete example of a thumbnail creation with @command{ffmpeg}:
9215 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
9221 Tile several successive frames together.
9223 The filter accepts the following options:
9228 Set the grid size (i.e. the number of lines and columns). For the syntax of
9229 this option, check the
9230 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
9233 Set the maximum number of frames to render in the given area. It must be less
9234 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
9235 the area will be used.
9238 Set the outer border margin in pixels.
9241 Set the inner border thickness (i.e. the number of pixels between frames). For
9242 more advanced padding options (such as having different values for the edges),
9243 refer to the pad video filter.
9246 Specify the color of the unused area. For the syntax of this option, check the
9247 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
9251 @subsection Examples
9255 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
9257 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
9259 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
9260 duplicating each output frame to accommodate the originally detected frame
9264 Display @code{5} pictures in an area of @code{3x2} frames,
9265 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
9266 mixed flat and named options:
9268 tile=3x2:nb_frames=5:padding=7:margin=2
9274 Perform various types of temporal field interlacing.
9276 Frames are counted starting from 1, so the first input frame is
9279 The filter accepts the following options:
9284 Specify the mode of the interlacing. This option can also be specified
9285 as a value alone. See below for a list of values for this option.
9287 Available values are:
9291 Move odd frames into the upper field, even into the lower field,
9292 generating a double height frame at half frame rate.
9296 Frame 1 Frame 2 Frame 3 Frame 4
9298 11111 22222 33333 44444
9299 11111 22222 33333 44444
9300 11111 22222 33333 44444
9301 11111 22222 33333 44444
9315 Only output even frames, odd frames are dropped, generating a frame with
9316 unchanged height at half frame rate.
9321 Frame 1 Frame 2 Frame 3 Frame 4
9323 11111 22222 33333 44444
9324 11111 22222 33333 44444
9325 11111 22222 33333 44444
9326 11111 22222 33333 44444
9336 Only output odd frames, even frames are dropped, generating a frame with
9337 unchanged height at half frame rate.
9342 Frame 1 Frame 2 Frame 3 Frame 4
9344 11111 22222 33333 44444
9345 11111 22222 33333 44444
9346 11111 22222 33333 44444
9347 11111 22222 33333 44444
9357 Expand each frame to full height, but pad alternate lines with black,
9358 generating a frame with double height at the same input frame rate.
9363 Frame 1 Frame 2 Frame 3 Frame 4
9365 11111 22222 33333 44444
9366 11111 22222 33333 44444
9367 11111 22222 33333 44444
9368 11111 22222 33333 44444
9371 11111 ..... 33333 .....
9372 ..... 22222 ..... 44444
9373 11111 ..... 33333 .....
9374 ..... 22222 ..... 44444
9375 11111 ..... 33333 .....
9376 ..... 22222 ..... 44444
9377 11111 ..... 33333 .....
9378 ..... 22222 ..... 44444
9382 @item interleave_top, 4
9383 Interleave the upper field from odd frames with the lower field from
9384 even frames, generating a frame with unchanged height at half frame rate.
9389 Frame 1 Frame 2 Frame 3 Frame 4
9391 11111<- 22222 33333<- 44444
9392 11111 22222<- 33333 44444<-
9393 11111<- 22222 33333<- 44444
9394 11111 22222<- 33333 44444<-
9404 @item interleave_bottom, 5
9405 Interleave the lower field from odd frames with the upper field from
9406 even frames, generating a frame with unchanged height at half frame rate.
9411 Frame 1 Frame 2 Frame 3 Frame 4
9413 11111 22222<- 33333 44444<-
9414 11111<- 22222 33333<- 44444
9415 11111 22222<- 33333 44444<-
9416 11111<- 22222 33333<- 44444
9426 @item interlacex2, 6
9427 Double frame rate with unchanged height. Frames are inserted each
9428 containing the second temporal field from the previous input frame and
9429 the first temporal field from the next input frame. This mode relies on
9430 the top_field_first flag. Useful for interlaced video displays with no
9431 field synchronisation.
9436 Frame 1 Frame 2 Frame 3 Frame 4
9438 11111 22222 33333 44444
9439 11111 22222 33333 44444
9440 11111 22222 33333 44444
9441 11111 22222 33333 44444
9444 11111 22222 22222 33333 33333 44444 44444
9445 11111 11111 22222 22222 33333 33333 44444
9446 11111 22222 22222 33333 33333 44444 44444
9447 11111 11111 22222 22222 33333 33333 44444
9453 Numeric values are deprecated but are accepted for backward
9454 compatibility reasons.
9456 Default mode is @code{merge}.
9459 Specify flags influencing the filter process.
9461 Available value for @var{flags} is:
9464 @item low_pass_filter, vlfp
9465 Enable vertical low-pass filtering in the filter.
9466 Vertical low-pass filtering is required when creating an interlaced
9467 destination from a progressive source which contains high-frequency
9468 vertical detail. Filtering will reduce interlace 'twitter' and Moire
9471 Vertical low-pass filtering can only be enabled for @option{mode}
9472 @var{interleave_top} and @var{interleave_bottom}.
9479 Transpose rows with columns in the input video and optionally flip it.
9481 It accepts the following parameters:
9486 Specify the transposition direction.
9488 Can assume the following values:
9490 @item 0, 4, cclock_flip
9491 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
9499 Rotate by 90 degrees clockwise, that is:
9507 Rotate by 90 degrees counterclockwise, that is:
9514 @item 3, 7, clock_flip
9515 Rotate by 90 degrees clockwise and vertically flip, that is:
9523 For values between 4-7, the transposition is only done if the input
9524 video geometry is portrait and not landscape. These values are
9525 deprecated, the @code{passthrough} option should be used instead.
9527 Numerical values are deprecated, and should be dropped in favor of
9531 Do not apply the transposition if the input geometry matches the one
9532 specified by the specified value. It accepts the following values:
9535 Always apply transposition.
9537 Preserve portrait geometry (when @var{height} >= @var{width}).
9539 Preserve landscape geometry (when @var{width} >= @var{height}).
9542 Default value is @code{none}.
9545 For example to rotate by 90 degrees clockwise and preserve portrait
9548 transpose=dir=1:passthrough=portrait
9551 The command above can also be specified as:
9553 transpose=1:portrait
9557 Trim the input so that the output contains one continuous subpart of the input.
9559 It accepts the following parameters:
9562 Specify the time of the start of the kept section, i.e. the frame with the
9563 timestamp @var{start} will be the first frame in the output.
9566 Specify the time of the first frame that will be dropped, i.e. the frame
9567 immediately preceding the one with the timestamp @var{end} will be the last
9568 frame in the output.
9571 This is the same as @var{start}, except this option sets the start timestamp
9572 in timebase units instead of seconds.
9575 This is the same as @var{end}, except this option sets the end timestamp
9576 in timebase units instead of seconds.
9579 The maximum duration of the output in seconds.
9582 The number of the first frame that should be passed to the output.
9585 The number of the first frame that should be dropped.
9588 @option{start}, @option{end}, and @option{duration} are expressed as time
9589 duration specifications; see
9590 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
9591 for the accepted syntax.
9593 Note that the first two sets of the start/end options and the @option{duration}
9594 option look at the frame timestamp, while the _frame variants simply count the
9595 frames that pass through the filter. Also note that this filter does not modify
9596 the timestamps. If you wish for the output timestamps to start at zero, insert a
9597 setpts filter after the trim filter.
9599 If multiple start or end options are set, this filter tries to be greedy and
9600 keep all the frames that match at least one of the specified constraints. To keep
9601 only the part that matches all the constraints at once, chain multiple trim
9604 The defaults are such that all the input is kept. So it is possible to set e.g.
9605 just the end values to keep everything before the specified time.
9610 Drop everything except the second minute of input:
9612 ffmpeg -i INPUT -vf trim=60:120
9616 Keep only the first second:
9618 ffmpeg -i INPUT -vf trim=duration=1
9627 Sharpen or blur the input video.
9629 It accepts the following parameters:
9632 @item luma_msize_x, lx
9633 Set the luma matrix horizontal size. It must be an odd integer between
9634 3 and 63. The default value is 5.
9636 @item luma_msize_y, ly
9637 Set the luma matrix vertical size. It must be an odd integer between 3
9638 and 63. The default value is 5.
9640 @item luma_amount, la
9641 Set the luma effect strength. It must be a floating point number, reasonable
9642 values lay between -1.5 and 1.5.
9644 Negative values will blur the input video, while positive values will
9645 sharpen it, a value of zero will disable the effect.
9647 Default value is 1.0.
9649 @item chroma_msize_x, cx
9650 Set the chroma matrix horizontal size. It must be an odd integer
9651 between 3 and 63. The default value is 5.
9653 @item chroma_msize_y, cy
9654 Set the chroma matrix vertical size. It must be an odd integer
9655 between 3 and 63. The default value is 5.
9657 @item chroma_amount, ca
9658 Set the chroma effect strength. It must be a floating point number, reasonable
9659 values lay between -1.5 and 1.5.
9661 Negative values will blur the input video, while positive values will
9662 sharpen it, a value of zero will disable the effect.
9664 Default value is 0.0.
9667 If set to 1, specify using OpenCL capabilities, only available if
9668 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
9672 All parameters are optional and default to the equivalent of the
9673 string '5:5:1.0:5:5:0.0'.
9675 @subsection Examples
9679 Apply strong luma sharpen effect:
9681 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
9685 Apply a strong blur of both luma and chroma parameters:
9687 unsharp=7:7:-2:7:7:-2
9693 Apply ultra slow/simple postprocessing filter that compresses and decompresses
9694 the image at several (or - in the case of @option{quality} level @code{8} - all)
9695 shifts and average the results.
9697 The way this differs from the behavior of spp is that uspp actually encodes &
9698 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
9699 DCT similar to MJPEG.
9701 The filter accepts the following options:
9705 Set quality. This option defines the number of levels for averaging. It accepts
9706 an integer in the range 0-8. If set to @code{0}, the filter will have no
9707 effect. A value of @code{8} means the higher quality. For each increment of
9708 that value the speed drops by a factor of approximately 2. Default value is
9712 Force a constant quantization parameter. If not set, the filter will use the QP
9713 from the video stream (if available).
9716 @anchor{vidstabdetect}
9717 @section vidstabdetect
9719 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
9720 @ref{vidstabtransform} for pass 2.
9722 This filter generates a file with relative translation and rotation
9723 transform information about subsequent frames, which is then used by
9724 the @ref{vidstabtransform} filter.
9726 To enable compilation of this filter you need to configure FFmpeg with
9727 @code{--enable-libvidstab}.
9729 This filter accepts the following options:
9733 Set the path to the file used to write the transforms information.
9734 Default value is @file{transforms.trf}.
9737 Set how shaky the video is and how quick the camera is. It accepts an
9738 integer in the range 1-10, a value of 1 means little shakiness, a
9739 value of 10 means strong shakiness. Default value is 5.
9742 Set the accuracy of the detection process. It must be a value in the
9743 range 1-15. A value of 1 means low accuracy, a value of 15 means high
9744 accuracy. Default value is 15.
9747 Set stepsize of the search process. The region around minimum is
9748 scanned with 1 pixel resolution. Default value is 6.
9751 Set minimum contrast. Below this value a local measurement field is
9752 discarded. Must be a floating point value in the range 0-1. Default
9756 Set reference frame number for tripod mode.
9758 If enabled, the motion of the frames is compared to a reference frame
9759 in the filtered stream, identified by the specified number. The idea
9760 is to compensate all movements in a more-or-less static scene and keep
9761 the camera view absolutely still.
9763 If set to 0, it is disabled. The frames are counted starting from 1.
9766 Show fields and transforms in the resulting frames. It accepts an
9767 integer in the range 0-2. Default value is 0, which disables any
9771 @subsection Examples
9781 Analyze strongly shaky movie and put the results in file
9782 @file{mytransforms.trf}:
9784 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
9788 Visualize the result of internal transformations in the resulting
9791 vidstabdetect=show=1
9795 Analyze a video with medium shakiness using @command{ffmpeg}:
9797 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
9801 @anchor{vidstabtransform}
9802 @section vidstabtransform
9804 Video stabilization/deshaking: pass 2 of 2,
9805 see @ref{vidstabdetect} for pass 1.
9807 Read a file with transform information for each frame and
9808 apply/compensate them. Together with the @ref{vidstabdetect}
9809 filter this can be used to deshake videos. See also
9810 @url{http://public.hronopik.de/vid.stab}. It is important to also use
9811 the @ref{unsharp} filter, see below.
9813 To enable compilation of this filter you need to configure FFmpeg with
9814 @code{--enable-libvidstab}.
9820 Set path to the file used to read the transforms. Default value is
9821 @file{transforms.trf}.
9824 Set the number of frames (value*2 + 1) used for lowpass filtering the
9825 camera movements. Default value is 10.
9827 For example a number of 10 means that 21 frames are used (10 in the
9828 past and 10 in the future) to smoothen the motion in the video. A
9829 larger value leads to a smoother video, but limits the acceleration of
9830 the camera (pan/tilt movements). 0 is a special case where a static
9831 camera is simulated.
9834 Set the camera path optimization algorithm.
9836 Accepted values are:
9839 gaussian kernel low-pass filter on camera motion (default)
9841 averaging on transformations
9845 Set maximal number of pixels to translate frames. Default value is -1,
9849 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
9850 value is -1, meaning no limit.
9853 Specify how to deal with borders that may be visible due to movement
9856 Available values are:
9859 keep image information from previous frame (default)
9861 fill the border black
9865 Invert transforms if set to 1. Default value is 0.
9868 Consider transforms as relative to previous frame if set to 1,
9869 absolute if set to 0. Default value is 0.
9872 Set percentage to zoom. A positive value will result in a zoom-in
9873 effect, a negative value in a zoom-out effect. Default value is 0 (no
9877 Set optimal zooming to avoid borders.
9879 Accepted values are:
9884 optimal static zoom value is determined (only very strong movements
9885 will lead to visible borders) (default)
9887 optimal adaptive zoom value is determined (no borders will be
9888 visible), see @option{zoomspeed}
9891 Note that the value given at zoom is added to the one calculated here.
9894 Set percent to zoom maximally each frame (enabled when
9895 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
9899 Specify type of interpolation.
9901 Available values are:
9906 linear only horizontal
9908 linear in both directions (default)
9910 cubic in both directions (slow)
9914 Enable virtual tripod mode if set to 1, which is equivalent to
9915 @code{relative=0:smoothing=0}. Default value is 0.
9917 Use also @code{tripod} option of @ref{vidstabdetect}.
9920 Increase log verbosity if set to 1. Also the detected global motions
9921 are written to the temporary file @file{global_motions.trf}. Default
9925 @subsection Examples
9929 Use @command{ffmpeg} for a typical stabilization with default values:
9931 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
9934 Note the use of the @ref{unsharp} filter which is always recommended.
9937 Zoom in a bit more and load transform data from a given file:
9939 vidstabtransform=zoom=5:input="mytransforms.trf"
9943 Smoothen the video even more:
9945 vidstabtransform=smoothing=30
9951 Flip the input video vertically.
9953 For example, to vertically flip a video with @command{ffmpeg}:
9955 ffmpeg -i in.avi -vf "vflip" out.avi
9961 Make or reverse a natural vignetting effect.
9963 The filter accepts the following options:
9967 Set lens angle expression as a number of radians.
9969 The value is clipped in the @code{[0,PI/2]} range.
9971 Default value: @code{"PI/5"}
9975 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
9979 Set forward/backward mode.
9981 Available modes are:
9984 The larger the distance from the central point, the darker the image becomes.
9987 The larger the distance from the central point, the brighter the image becomes.
9988 This can be used to reverse a vignette effect, though there is no automatic
9989 detection to extract the lens @option{angle} and other settings (yet). It can
9990 also be used to create a burning effect.
9993 Default value is @samp{forward}.
9996 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
9998 It accepts the following values:
10001 Evaluate expressions only once during the filter initialization.
10004 Evaluate expressions for each incoming frame. This is way slower than the
10005 @samp{init} mode since it requires all the scalers to be re-computed, but it
10006 allows advanced dynamic expressions.
10009 Default value is @samp{init}.
10012 Set dithering to reduce the circular banding effects. Default is @code{1}
10016 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
10017 Setting this value to the SAR of the input will make a rectangular vignetting
10018 following the dimensions of the video.
10020 Default is @code{1/1}.
10023 @subsection Expressions
10025 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
10026 following parameters.
10031 input width and height
10034 the number of input frame, starting from 0
10037 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
10038 @var{TB} units, NAN if undefined
10041 frame rate of the input video, NAN if the input frame rate is unknown
10044 the PTS (Presentation TimeStamp) of the filtered video frame,
10045 expressed in seconds, NAN if undefined
10048 time base of the input video
10052 @subsection Examples
10056 Apply simple strong vignetting effect:
10062 Make a flickering vignetting:
10064 vignette='PI/4+random(1)*PI/50':eval=frame
10071 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
10072 Deinterlacing Filter").
10074 Based on the process described by Martin Weston for BBC R&D, and
10075 implemented based on the de-interlace algorithm written by Jim
10076 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
10077 uses filter coefficients calculated by BBC R&D.
10079 There are two sets of filter coefficients, so called "simple":
10080 and "complex". Which set of filter coefficients is used can
10081 be set by passing an optional parameter:
10085 Set the interlacing filter coefficients. Accepts one of the following values:
10089 Simple filter coefficient set.
10091 More-complex filter coefficient set.
10093 Default value is @samp{complex}.
10096 Specify which frames to deinterlace. Accept one of the following values:
10100 Deinterlace all frames,
10102 Only deinterlace frames marked as interlaced.
10105 Default value is @samp{all}.
10109 Apply the xBR high-quality magnification filter which is designed for pixel
10110 art. It follows a set of edge-detection rules, see
10111 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
10113 It accepts the following option:
10117 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
10118 @code{3xBR} and @code{4} for @code{4xBR}.
10119 Default is @code{3}.
10125 Deinterlace the input video ("yadif" means "yet another deinterlacing
10128 It accepts the following parameters:
10134 The interlacing mode to adopt. It accepts one of the following values:
10137 @item 0, send_frame
10138 Output one frame for each frame.
10139 @item 1, send_field
10140 Output one frame for each field.
10141 @item 2, send_frame_nospatial
10142 Like @code{send_frame}, but it skips the spatial interlacing check.
10143 @item 3, send_field_nospatial
10144 Like @code{send_field}, but it skips the spatial interlacing check.
10147 The default value is @code{send_frame}.
10150 The picture field parity assumed for the input interlaced video. It accepts one
10151 of the following values:
10155 Assume the top field is first.
10157 Assume the bottom field is first.
10159 Enable automatic detection of field parity.
10162 The default value is @code{auto}.
10163 If the interlacing is unknown or the decoder does not export this information,
10164 top field first will be assumed.
10167 Specify which frames to deinterlace. Accept one of the following
10172 Deinterlace all frames.
10173 @item 1, interlaced
10174 Only deinterlace frames marked as interlaced.
10177 The default value is @code{all}.
10182 Apply Zoom & Pan effect.
10184 This filter accepts the following options:
10188 Set the zoom expression. Default is 1.
10192 Set the x and y expression. Default is 0.
10195 Set the duration expression in number of frames.
10196 This sets for how many number of frames effect will last for
10197 single input image.
10200 Set the output image size, default is 'hd720'.
10203 Each expression can contain the following constants:
10222 Output frame count.
10226 Last calculated 'x' and 'y' position from 'x' and 'y' expression
10227 for current input frame.
10231 'x' and 'y' of last output frame of previous input frame or 0 when there was
10232 not yet such frame (first input frame).
10235 Last calculated zoom from 'z' expression for current input frame.
10238 Last calculated zoom of last output frame of previous input frame.
10241 Number of output frames for current input frame. Calculated from 'd' expression
10242 for each input frame.
10245 number of output frames created for previous input frame
10248 Rational number: input width / input height
10251 sample aspect ratio
10254 display aspect ratio
10258 @subsection Examples
10262 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
10264 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
10268 Zoom-in up to 1.5 and pan always at center of picture:
10270 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
10274 @c man end VIDEO FILTERS
10276 @chapter Video Sources
10277 @c man begin VIDEO SOURCES
10279 Below is a description of the currently available video sources.
10283 Buffer video frames, and make them available to the filter chain.
10285 This source is mainly intended for a programmatic use, in particular
10286 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
10288 It accepts the following parameters:
10293 Specify the size (width and height) of the buffered video frames. For the
10294 syntax of this option, check the
10295 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10298 The input video width.
10301 The input video height.
10304 A string representing the pixel format of the buffered video frames.
10305 It may be a number corresponding to a pixel format, or a pixel format
10309 Specify the timebase assumed by the timestamps of the buffered frames.
10312 Specify the frame rate expected for the video stream.
10314 @item pixel_aspect, sar
10315 The sample (pixel) aspect ratio of the input video.
10318 Specify the optional parameters to be used for the scale filter which
10319 is automatically inserted when an input change is detected in the
10320 input size or format.
10325 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
10328 will instruct the source to accept video frames with size 320x240 and
10329 with format "yuv410p", assuming 1/24 as the timestamps timebase and
10330 square pixels (1:1 sample aspect ratio).
10331 Since the pixel format with name "yuv410p" corresponds to the number 6
10332 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
10333 this example corresponds to:
10335 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
10338 Alternatively, the options can be specified as a flat string, but this
10339 syntax is deprecated:
10341 @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}]
10345 Create a pattern generated by an elementary cellular automaton.
10347 The initial state of the cellular automaton can be defined through the
10348 @option{filename}, and @option{pattern} options. If such options are
10349 not specified an initial state is created randomly.
10351 At each new frame a new row in the video is filled with the result of
10352 the cellular automaton next generation. The behavior when the whole
10353 frame is filled is defined by the @option{scroll} option.
10355 This source accepts the following options:
10359 Read the initial cellular automaton state, i.e. the starting row, from
10360 the specified file.
10361 In the file, each non-whitespace character is considered an alive
10362 cell, a newline will terminate the row, and further characters in the
10363 file will be ignored.
10366 Read the initial cellular automaton state, i.e. the starting row, from
10367 the specified string.
10369 Each non-whitespace character in the string is considered an alive
10370 cell, a newline will terminate the row, and further characters in the
10371 string will be ignored.
10374 Set the video rate, that is the number of frames generated per second.
10377 @item random_fill_ratio, ratio
10378 Set the random fill ratio for the initial cellular automaton row. It
10379 is a floating point number value ranging from 0 to 1, defaults to
10382 This option is ignored when a file or a pattern is specified.
10384 @item random_seed, seed
10385 Set the seed for filling randomly the initial row, must be an integer
10386 included between 0 and UINT32_MAX. If not specified, or if explicitly
10387 set to -1, the filter will try to use a good random seed on a best
10391 Set the cellular automaton rule, it is a number ranging from 0 to 255.
10392 Default value is 110.
10395 Set the size of the output video. For the syntax of this option, check the
10396 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10398 If @option{filename} or @option{pattern} is specified, the size is set
10399 by default to the width of the specified initial state row, and the
10400 height is set to @var{width} * PHI.
10402 If @option{size} is set, it must contain the width of the specified
10403 pattern string, and the specified pattern will be centered in the
10406 If a filename or a pattern string is not specified, the size value
10407 defaults to "320x518" (used for a randomly generated initial state).
10410 If set to 1, scroll the output upward when all the rows in the output
10411 have been already filled. If set to 0, the new generated row will be
10412 written over the top row just after the bottom row is filled.
10415 @item start_full, full
10416 If set to 1, completely fill the output with generated rows before
10417 outputting the first frame.
10418 This is the default behavior, for disabling set the value to 0.
10421 If set to 1, stitch the left and right row edges together.
10422 This is the default behavior, for disabling set the value to 0.
10425 @subsection Examples
10429 Read the initial state from @file{pattern}, and specify an output of
10432 cellauto=f=pattern:s=200x400
10436 Generate a random initial row with a width of 200 cells, with a fill
10439 cellauto=ratio=2/3:s=200x200
10443 Create a pattern generated by rule 18 starting by a single alive cell
10444 centered on an initial row with width 100:
10446 cellauto=p=@@:s=100x400:full=0:rule=18
10450 Specify a more elaborated initial pattern:
10452 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
10457 @section mandelbrot
10459 Generate a Mandelbrot set fractal, and progressively zoom towards the
10460 point specified with @var{start_x} and @var{start_y}.
10462 This source accepts the following options:
10467 Set the terminal pts value. Default value is 400.
10470 Set the terminal scale value.
10471 Must be a floating point value. Default value is 0.3.
10474 Set the inner coloring mode, that is the algorithm used to draw the
10475 Mandelbrot fractal internal region.
10477 It shall assume one of the following values:
10482 Show time until convergence.
10484 Set color based on point closest to the origin of the iterations.
10489 Default value is @var{mincol}.
10492 Set the bailout value. Default value is 10.0.
10495 Set the maximum of iterations performed by the rendering
10496 algorithm. Default value is 7189.
10499 Set outer coloring mode.
10500 It shall assume one of following values:
10502 @item iteration_count
10503 Set iteration cound mode.
10504 @item normalized_iteration_count
10505 set normalized iteration count mode.
10507 Default value is @var{normalized_iteration_count}.
10510 Set frame rate, expressed as number of frames per second. Default
10514 Set frame size. For the syntax of this option, check the "Video
10515 size" section in the ffmpeg-utils manual. Default value is "640x480".
10518 Set the initial scale value. Default value is 3.0.
10521 Set the initial x position. Must be a floating point value between
10522 -100 and 100. Default value is -0.743643887037158704752191506114774.
10525 Set the initial y position. Must be a floating point value between
10526 -100 and 100. Default value is -0.131825904205311970493132056385139.
10531 Generate various test patterns, as generated by the MPlayer test filter.
10533 The size of the generated video is fixed, and is 256x256.
10534 This source is useful in particular for testing encoding features.
10536 This source accepts the following options:
10541 Specify the frame rate of the sourced video, as the number of frames
10542 generated per second. It has to be a string in the format
10543 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
10544 number or a valid video frame rate abbreviation. The default value is
10548 Set the duration of the sourced video. See
10549 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
10550 for the accepted syntax.
10552 If not specified, or the expressed duration is negative, the video is
10553 supposed to be generated forever.
10557 Set the number or the name of the test to perform. Supported tests are:
10573 Default value is "all", which will cycle through the list of all tests.
10578 mptestsrc=t=dc_luma
10581 will generate a "dc_luma" test pattern.
10583 @section frei0r_src
10585 Provide a frei0r source.
10587 To enable compilation of this filter you need to install the frei0r
10588 header and configure FFmpeg with @code{--enable-frei0r}.
10590 This source accepts the following parameters:
10595 The size of the video to generate. For the syntax of this option, check the
10596 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10599 The framerate of the generated video. It may be a string of the form
10600 @var{num}/@var{den} or a frame rate abbreviation.
10603 The name to the frei0r source to load. For more information regarding frei0r and
10604 how to set the parameters, read the @ref{frei0r} section in the video filters
10607 @item filter_params
10608 A '|'-separated list of parameters to pass to the frei0r source.
10612 For example, to generate a frei0r partik0l source with size 200x200
10613 and frame rate 10 which is overlaid on the overlay filter main input:
10615 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
10620 Generate a life pattern.
10622 This source is based on a generalization of John Conway's life game.
10624 The sourced input represents a life grid, each pixel represents a cell
10625 which can be in one of two possible states, alive or dead. Every cell
10626 interacts with its eight neighbours, which are the cells that are
10627 horizontally, vertically, or diagonally adjacent.
10629 At each interaction the grid evolves according to the adopted rule,
10630 which specifies the number of neighbor alive cells which will make a
10631 cell stay alive or born. The @option{rule} option allows one to specify
10634 This source accepts the following options:
10638 Set the file from which to read the initial grid state. In the file,
10639 each non-whitespace character is considered an alive cell, and newline
10640 is used to delimit the end of each row.
10642 If this option is not specified, the initial grid is generated
10646 Set the video rate, that is the number of frames generated per second.
10649 @item random_fill_ratio, ratio
10650 Set the random fill ratio for the initial random grid. It is a
10651 floating point number value ranging from 0 to 1, defaults to 1/PHI.
10652 It is ignored when a file is specified.
10654 @item random_seed, seed
10655 Set the seed for filling the initial random grid, must be an integer
10656 included between 0 and UINT32_MAX. If not specified, or if explicitly
10657 set to -1, the filter will try to use a good random seed on a best
10663 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
10664 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
10665 @var{NS} specifies the number of alive neighbor cells which make a
10666 live cell stay alive, and @var{NB} the number of alive neighbor cells
10667 which make a dead cell to become alive (i.e. to "born").
10668 "s" and "b" can be used in place of "S" and "B", respectively.
10670 Alternatively a rule can be specified by an 18-bits integer. The 9
10671 high order bits are used to encode the next cell state if it is alive
10672 for each number of neighbor alive cells, the low order bits specify
10673 the rule for "borning" new cells. Higher order bits encode for an
10674 higher number of neighbor cells.
10675 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
10676 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
10678 Default value is "S23/B3", which is the original Conway's game of life
10679 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
10680 cells, and will born a new cell if there are three alive cells around
10684 Set the size of the output video. For the syntax of this option, check the
10685 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10687 If @option{filename} is specified, the size is set by default to the
10688 same size of the input file. If @option{size} is set, it must contain
10689 the size specified in the input file, and the initial grid defined in
10690 that file is centered in the larger resulting area.
10692 If a filename is not specified, the size value defaults to "320x240"
10693 (used for a randomly generated initial grid).
10696 If set to 1, stitch the left and right grid edges together, and the
10697 top and bottom edges also. Defaults to 1.
10700 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
10701 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
10702 value from 0 to 255.
10705 Set the color of living (or new born) cells.
10708 Set the color of dead cells. If @option{mold} is set, this is the first color
10709 used to represent a dead cell.
10712 Set mold color, for definitely dead and moldy cells.
10714 For the syntax of these 3 color options, check the "Color" section in the
10715 ffmpeg-utils manual.
10718 @subsection Examples
10722 Read a grid from @file{pattern}, and center it on a grid of size
10725 life=f=pattern:s=300x300
10729 Generate a random grid of size 200x200, with a fill ratio of 2/3:
10731 life=ratio=2/3:s=200x200
10735 Specify a custom rule for evolving a randomly generated grid:
10741 Full example with slow death effect (mold) using @command{ffplay}:
10743 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
10748 @anchor{haldclutsrc}
10750 @anchor{rgbtestsrc}
10752 @anchor{smptehdbars}
10754 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
10756 The @code{color} source provides an uniformly colored input.
10758 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
10759 @ref{haldclut} filter.
10761 The @code{nullsrc} source returns unprocessed video frames. It is
10762 mainly useful to be employed in analysis / debugging tools, or as the
10763 source for filters which ignore the input data.
10765 The @code{rgbtestsrc} source generates an RGB test pattern useful for
10766 detecting RGB vs BGR issues. You should see a red, green and blue
10767 stripe from top to bottom.
10769 The @code{smptebars} source generates a color bars pattern, based on
10770 the SMPTE Engineering Guideline EG 1-1990.
10772 The @code{smptehdbars} source generates a color bars pattern, based on
10773 the SMPTE RP 219-2002.
10775 The @code{testsrc} source generates a test video pattern, showing a
10776 color pattern, a scrolling gradient and a timestamp. This is mainly
10777 intended for testing purposes.
10779 The sources accept the following parameters:
10784 Specify the color of the source, only available in the @code{color}
10785 source. For the syntax of this option, check the "Color" section in the
10786 ffmpeg-utils manual.
10789 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
10790 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
10791 pixels to be used as identity matrix for 3D lookup tables. Each component is
10792 coded on a @code{1/(N*N)} scale.
10795 Specify the size of the sourced video. For the syntax of this option, check the
10796 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10797 The default value is @code{320x240}.
10799 This option is not available with the @code{haldclutsrc} filter.
10802 Specify the frame rate of the sourced video, as the number of frames
10803 generated per second. It has to be a string in the format
10804 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
10805 number or a valid video frame rate abbreviation. The default value is
10809 Set the sample aspect ratio of the sourced video.
10812 Set the duration of the sourced video. See
10813 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
10814 for the accepted syntax.
10816 If not specified, or the expressed duration is negative, the video is
10817 supposed to be generated forever.
10820 Set the number of decimals to show in the timestamp, only available in the
10821 @code{testsrc} source.
10823 The displayed timestamp value will correspond to the original
10824 timestamp value multiplied by the power of 10 of the specified
10825 value. Default value is 0.
10828 For example the following:
10830 testsrc=duration=5.3:size=qcif:rate=10
10833 will generate a video with a duration of 5.3 seconds, with size
10834 176x144 and a frame rate of 10 frames per second.
10836 The following graph description will generate a red source
10837 with an opacity of 0.2, with size "qcif" and a frame rate of 10
10840 color=c=red@@0.2:s=qcif:r=10
10843 If the input content is to be ignored, @code{nullsrc} can be used. The
10844 following command generates noise in the luminance plane by employing
10845 the @code{geq} filter:
10847 nullsrc=s=256x256, geq=random(1)*255:128:128
10850 @subsection Commands
10852 The @code{color} source supports the following commands:
10856 Set the color of the created image. Accepts the same syntax of the
10857 corresponding @option{color} option.
10860 @c man end VIDEO SOURCES
10862 @chapter Video Sinks
10863 @c man begin VIDEO SINKS
10865 Below is a description of the currently available video sinks.
10867 @section buffersink
10869 Buffer video frames, and make them available to the end of the filter
10872 This sink is mainly intended for programmatic use, in particular
10873 through the interface defined in @file{libavfilter/buffersink.h}
10874 or the options system.
10876 It accepts a pointer to an AVBufferSinkContext structure, which
10877 defines the incoming buffers' formats, to be passed as the opaque
10878 parameter to @code{avfilter_init_filter} for initialization.
10882 Null video sink: do absolutely nothing with the input video. It is
10883 mainly useful as a template and for use in analysis / debugging
10886 @c man end VIDEO SINKS
10888 @chapter Multimedia Filters
10889 @c man begin MULTIMEDIA FILTERS
10891 Below is a description of the currently available multimedia filters.
10893 @section avectorscope
10895 Convert input audio to a video output, representing the audio vector
10898 The filter is used to measure the difference between channels of stereo
10899 audio stream. A monoaural signal, consisting of identical left and right
10900 signal, results in straight vertical line. Any stereo separation is visible
10901 as a deviation from this line, creating a Lissajous figure.
10902 If the straight (or deviation from it) but horizontal line appears this
10903 indicates that the left and right channels are out of phase.
10905 The filter accepts the following options:
10909 Set the vectorscope mode.
10911 Available values are:
10914 Lissajous rotated by 45 degrees.
10917 Same as above but not rotated.
10920 Default value is @samp{lissajous}.
10923 Set the video size for the output. For the syntax of this option, check the
10924 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10925 Default value is @code{400x400}.
10928 Set the output frame rate. Default value is @code{25}.
10933 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
10934 Allowed range is @code{[0, 255]}.
10939 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
10940 Allowed range is @code{[0, 255]}.
10943 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
10946 @subsection Examples
10950 Complete example using @command{ffplay}:
10952 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10953 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
10959 Concatenate audio and video streams, joining them together one after the
10962 The filter works on segments of synchronized video and audio streams. All
10963 segments must have the same number of streams of each type, and that will
10964 also be the number of streams at output.
10966 The filter accepts the following options:
10971 Set the number of segments. Default is 2.
10974 Set the number of output video streams, that is also the number of video
10975 streams in each segment. Default is 1.
10978 Set the number of output audio streams, that is also the number of audio
10979 streams in each segment. Default is 0.
10982 Activate unsafe mode: do not fail if segments have a different format.
10986 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
10987 @var{a} audio outputs.
10989 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
10990 segment, in the same order as the outputs, then the inputs for the second
10993 Related streams do not always have exactly the same duration, for various
10994 reasons including codec frame size or sloppy authoring. For that reason,
10995 related synchronized streams (e.g. a video and its audio track) should be
10996 concatenated at once. The concat filter will use the duration of the longest
10997 stream in each segment (except the last one), and if necessary pad shorter
10998 audio streams with silence.
11000 For this filter to work correctly, all segments must start at timestamp 0.
11002 All corresponding streams must have the same parameters in all segments; the
11003 filtering system will automatically select a common pixel format for video
11004 streams, and a common sample format, sample rate and channel layout for
11005 audio streams, but other settings, such as resolution, must be converted
11006 explicitly by the user.
11008 Different frame rates are acceptable but will result in variable frame rate
11009 at output; be sure to configure the output file to handle it.
11011 @subsection Examples
11015 Concatenate an opening, an episode and an ending, all in bilingual version
11016 (video in stream 0, audio in streams 1 and 2):
11018 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
11019 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
11020 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
11021 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
11025 Concatenate two parts, handling audio and video separately, using the
11026 (a)movie sources, and adjusting the resolution:
11028 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
11029 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
11030 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
11032 Note that a desync will happen at the stitch if the audio and video streams
11033 do not have exactly the same duration in the first file.
11039 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
11040 it unchanged. By default, it logs a message at a frequency of 10Hz with the
11041 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
11042 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
11044 The filter also has a video output (see the @var{video} option) with a real
11045 time graph to observe the loudness evolution. The graphic contains the logged
11046 message mentioned above, so it is not printed anymore when this option is set,
11047 unless the verbose logging is set. The main graphing area contains the
11048 short-term loudness (3 seconds of analysis), and the gauge on the right is for
11049 the momentary loudness (400 milliseconds).
11051 More information about the Loudness Recommendation EBU R128 on
11052 @url{http://tech.ebu.ch/loudness}.
11054 The filter accepts the following options:
11059 Activate the video output. The audio stream is passed unchanged whether this
11060 option is set or no. The video stream will be the first output stream if
11061 activated. Default is @code{0}.
11064 Set the video size. This option is for video only. For the syntax of this
11066 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11067 Default and minimum resolution is @code{640x480}.
11070 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
11071 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
11072 other integer value between this range is allowed.
11075 Set metadata injection. If set to @code{1}, the audio input will be segmented
11076 into 100ms output frames, each of them containing various loudness information
11077 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
11079 Default is @code{0}.
11082 Force the frame logging level.
11084 Available values are:
11087 information logging level
11089 verbose logging level
11092 By default, the logging level is set to @var{info}. If the @option{video} or
11093 the @option{metadata} options are set, it switches to @var{verbose}.
11098 Available modes can be cumulated (the option is a @code{flag} type). Possible
11102 Disable any peak mode (default).
11104 Enable sample-peak mode.
11106 Simple peak mode looking for the higher sample value. It logs a message
11107 for sample-peak (identified by @code{SPK}).
11109 Enable true-peak mode.
11111 If enabled, the peak lookup is done on an over-sampled version of the input
11112 stream for better peak accuracy. It logs a message for true-peak.
11113 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
11114 This mode requires a build with @code{libswresample}.
11119 @subsection Examples
11123 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
11125 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
11129 Run an analysis with @command{ffmpeg}:
11131 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
11135 @section interleave, ainterleave
11137 Temporally interleave frames from several inputs.
11139 @code{interleave} works with video inputs, @code{ainterleave} with audio.
11141 These filters read frames from several inputs and send the oldest
11142 queued frame to the output.
11144 Input streams must have a well defined, monotonically increasing frame
11147 In order to submit one frame to output, these filters need to enqueue
11148 at least one frame for each input, so they cannot work in case one
11149 input is not yet terminated and will not receive incoming frames.
11151 For example consider the case when one input is a @code{select} filter
11152 which always drop input frames. The @code{interleave} filter will keep
11153 reading from that input, but it will never be able to send new frames
11154 to output until the input will send an end-of-stream signal.
11156 Also, depending on inputs synchronization, the filters will drop
11157 frames in case one input receives more frames than the other ones, and
11158 the queue is already filled.
11160 These filters accept the following options:
11164 Set the number of different inputs, it is 2 by default.
11167 @subsection Examples
11171 Interleave frames belonging to different streams using @command{ffmpeg}:
11173 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
11177 Add flickering blur effect:
11179 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
11183 @section perms, aperms
11185 Set read/write permissions for the output frames.
11187 These filters are mainly aimed at developers to test direct path in the
11188 following filter in the filtergraph.
11190 The filters accept the following options:
11194 Select the permissions mode.
11196 It accepts the following values:
11199 Do nothing. This is the default.
11201 Set all the output frames read-only.
11203 Set all the output frames directly writable.
11205 Make the frame read-only if writable, and writable if read-only.
11207 Set each output frame read-only or writable randomly.
11211 Set the seed for the @var{random} mode, must be an integer included between
11212 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
11213 @code{-1}, the filter will try to use a good random seed on a best effort
11217 Note: in case of auto-inserted filter between the permission filter and the
11218 following one, the permission might not be received as expected in that
11219 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
11220 perms/aperms filter can avoid this problem.
11222 @section select, aselect
11224 Select frames to pass in output.
11226 This filter accepts the following options:
11231 Set expression, which is evaluated for each input frame.
11233 If the expression is evaluated to zero, the frame is discarded.
11235 If the evaluation result is negative or NaN, the frame is sent to the
11236 first output; otherwise it is sent to the output with index
11237 @code{ceil(val)-1}, assuming that the input index starts from 0.
11239 For example a value of @code{1.2} corresponds to the output with index
11240 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
11243 Set the number of outputs. The output to which to send the selected
11244 frame is based on the result of the evaluation. Default value is 1.
11247 The expression can contain the following constants:
11251 The (sequential) number of the filtered frame, starting from 0.
11254 The (sequential) number of the selected frame, starting from 0.
11256 @item prev_selected_n
11257 The sequential number of the last selected frame. It's NAN if undefined.
11260 The timebase of the input timestamps.
11263 The PTS (Presentation TimeStamp) of the filtered video frame,
11264 expressed in @var{TB} units. It's NAN if undefined.
11267 The PTS of the filtered video frame,
11268 expressed in seconds. It's NAN if undefined.
11271 The PTS of the previously filtered video frame. It's NAN if undefined.
11273 @item prev_selected_pts
11274 The PTS of the last previously filtered video frame. It's NAN if undefined.
11276 @item prev_selected_t
11277 The PTS of the last previously selected video frame. It's NAN if undefined.
11280 The PTS of the first video frame in the video. It's NAN if undefined.
11283 The time of the first video frame in the video. It's NAN if undefined.
11285 @item pict_type @emph{(video only)}
11286 The type of the filtered frame. It can assume one of the following
11298 @item interlace_type @emph{(video only)}
11299 The frame interlace type. It can assume one of the following values:
11302 The frame is progressive (not interlaced).
11304 The frame is top-field-first.
11306 The frame is bottom-field-first.
11309 @item consumed_sample_n @emph{(audio only)}
11310 the number of selected samples before the current frame
11312 @item samples_n @emph{(audio only)}
11313 the number of samples in the current frame
11315 @item sample_rate @emph{(audio only)}
11316 the input sample rate
11319 This is 1 if the filtered frame is a key-frame, 0 otherwise.
11322 the position in the file of the filtered frame, -1 if the information
11323 is not available (e.g. for synthetic video)
11325 @item scene @emph{(video only)}
11326 value between 0 and 1 to indicate a new scene; a low value reflects a low
11327 probability for the current frame to introduce a new scene, while a higher
11328 value means the current frame is more likely to be one (see the example below)
11332 The default value of the select expression is "1".
11334 @subsection Examples
11338 Select all frames in input:
11343 The example above is the same as:
11355 Select only I-frames:
11357 select='eq(pict_type\,I)'
11361 Select one frame every 100:
11363 select='not(mod(n\,100))'
11367 Select only frames contained in the 10-20 time interval:
11369 select=between(t\,10\,20)
11373 Select only I frames contained in the 10-20 time interval:
11375 select=between(t\,10\,20)*eq(pict_type\,I)
11379 Select frames with a minimum distance of 10 seconds:
11381 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
11385 Use aselect to select only audio frames with samples number > 100:
11387 aselect='gt(samples_n\,100)'
11391 Create a mosaic of the first scenes:
11393 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
11396 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
11400 Send even and odd frames to separate outputs, and compose them:
11402 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
11406 @section sendcmd, asendcmd
11408 Send commands to filters in the filtergraph.
11410 These filters read commands to be sent to other filters in the
11413 @code{sendcmd} must be inserted between two video filters,
11414 @code{asendcmd} must be inserted between two audio filters, but apart
11415 from that they act the same way.
11417 The specification of commands can be provided in the filter arguments
11418 with the @var{commands} option, or in a file specified by the
11419 @var{filename} option.
11421 These filters accept the following options:
11424 Set the commands to be read and sent to the other filters.
11426 Set the filename of the commands to be read and sent to the other
11430 @subsection Commands syntax
11432 A commands description consists of a sequence of interval
11433 specifications, comprising a list of commands to be executed when a
11434 particular event related to that interval occurs. The occurring event
11435 is typically the current frame time entering or leaving a given time
11438 An interval is specified by the following syntax:
11440 @var{START}[-@var{END}] @var{COMMANDS};
11443 The time interval is specified by the @var{START} and @var{END} times.
11444 @var{END} is optional and defaults to the maximum time.
11446 The current frame time is considered within the specified interval if
11447 it is included in the interval [@var{START}, @var{END}), that is when
11448 the time is greater or equal to @var{START} and is lesser than
11451 @var{COMMANDS} consists of a sequence of one or more command
11452 specifications, separated by ",", relating to that interval. The
11453 syntax of a command specification is given by:
11455 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
11458 @var{FLAGS} is optional and specifies the type of events relating to
11459 the time interval which enable sending the specified command, and must
11460 be a non-null sequence of identifier flags separated by "+" or "|" and
11461 enclosed between "[" and "]".
11463 The following flags are recognized:
11466 The command is sent when the current frame timestamp enters the
11467 specified interval. In other words, the command is sent when the
11468 previous frame timestamp was not in the given interval, and the
11472 The command is sent when the current frame timestamp leaves the
11473 specified interval. In other words, the command is sent when the
11474 previous frame timestamp was in the given interval, and the
11478 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
11481 @var{TARGET} specifies the target of the command, usually the name of
11482 the filter class or a specific filter instance name.
11484 @var{COMMAND} specifies the name of the command for the target filter.
11486 @var{ARG} is optional and specifies the optional list of argument for
11487 the given @var{COMMAND}.
11489 Between one interval specification and another, whitespaces, or
11490 sequences of characters starting with @code{#} until the end of line,
11491 are ignored and can be used to annotate comments.
11493 A simplified BNF description of the commands specification syntax
11496 @var{COMMAND_FLAG} ::= "enter" | "leave"
11497 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
11498 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
11499 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
11500 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
11501 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
11504 @subsection Examples
11508 Specify audio tempo change at second 4:
11510 asendcmd=c='4.0 atempo tempo 1.5',atempo
11514 Specify a list of drawtext and hue commands in a file.
11516 # show text in the interval 5-10
11517 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
11518 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
11520 # desaturate the image in the interval 15-20
11521 15.0-20.0 [enter] hue s 0,
11522 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
11524 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
11526 # apply an exponential saturation fade-out effect, starting from time 25
11527 25 [enter] hue s exp(25-t)
11530 A filtergraph allowing to read and process the above command list
11531 stored in a file @file{test.cmd}, can be specified with:
11533 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
11538 @section setpts, asetpts
11540 Change the PTS (presentation timestamp) of the input frames.
11542 @code{setpts} works on video frames, @code{asetpts} on audio frames.
11544 This filter accepts the following options:
11549 The expression which is evaluated for each frame to construct its timestamp.
11553 The expression is evaluated through the eval API and can contain the following
11558 frame rate, only defined for constant frame-rate video
11561 The presentation timestamp in input
11564 The count of the input frame for video or the number of consumed samples,
11565 not including the current frame for audio, starting from 0.
11567 @item NB_CONSUMED_SAMPLES
11568 The number of consumed samples, not including the current frame (only
11571 @item NB_SAMPLES, S
11572 The number of samples in the current frame (only audio)
11574 @item SAMPLE_RATE, SR
11575 The audio sample rate.
11578 The PTS of the first frame.
11581 the time in seconds of the first frame
11584 State whether the current frame is interlaced.
11587 the time in seconds of the current frame
11590 original position in the file of the frame, or undefined if undefined
11591 for the current frame
11594 The previous input PTS.
11597 previous input time in seconds
11600 The previous output PTS.
11603 previous output time in seconds
11606 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
11610 The wallclock (RTC) time at the start of the movie in microseconds.
11613 The timebase of the input timestamps.
11617 @subsection Examples
11621 Start counting PTS from zero
11623 setpts=PTS-STARTPTS
11627 Apply fast motion effect:
11633 Apply slow motion effect:
11639 Set fixed rate of 25 frames per second:
11645 Set fixed rate 25 fps with some jitter:
11647 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
11651 Apply an offset of 10 seconds to the input PTS:
11657 Generate timestamps from a "live source" and rebase onto the current timebase:
11659 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
11663 Generate timestamps by counting samples:
11670 @section settb, asettb
11672 Set the timebase to use for the output frames timestamps.
11673 It is mainly useful for testing timebase configuration.
11675 It accepts the following parameters:
11680 The expression which is evaluated into the output timebase.
11684 The value for @option{tb} is an arithmetic expression representing a
11685 rational. The expression can contain the constants "AVTB" (the default
11686 timebase), "intb" (the input timebase) and "sr" (the sample rate,
11687 audio only). Default value is "intb".
11689 @subsection Examples
11693 Set the timebase to 1/25:
11699 Set the timebase to 1/10:
11705 Set the timebase to 1001/1000:
11711 Set the timebase to 2*intb:
11717 Set the default timebase value:
11724 Convert input audio to a video output representing
11725 frequency spectrum logarithmically (using constant Q transform with
11726 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
11728 The filter accepts the following options:
11732 Specify transform volume (multiplier) expression. The expression can contain
11735 @item frequency, freq, f
11736 the frequency where transform is evaluated
11737 @item timeclamp, tc
11738 value of timeclamp option
11742 @item a_weighting(f)
11743 A-weighting of equal loudness
11744 @item b_weighting(f)
11745 B-weighting of equal loudness
11746 @item c_weighting(f)
11747 C-weighting of equal loudness
11749 Default value is @code{16}.
11752 Specify transform length expression. The expression can contain variables:
11754 @item frequency, freq, f
11755 the frequency where transform is evaluated
11756 @item timeclamp, tc
11757 value of timeclamp option
11759 Default value is @code{384/f*tc/(384/f+tc)}.
11762 Specify the transform timeclamp. At low frequency, there is trade-off between
11763 accuracy in time domain and frequency domain. If timeclamp is lower,
11764 event in time domain is represented more accurately (such as fast bass drum),
11765 otherwise event in frequency domain is represented more accurately
11766 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
11769 Specify the transform coeffclamp. If coeffclamp is lower, transform is
11770 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
11771 Default value is @code{1.0}.
11774 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
11775 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
11776 Default value is @code{3.0}.
11779 Specify gamma of bargraph. Acceptable value is [1.0, 7.0].
11780 Default value is @code{1.0}.
11783 Specify font file for use with freetype. If not specified, use embedded font.
11786 Specify font color expression. This is arithmetic expression that should return
11787 integer value 0xRRGGBB. The expression can contain variables:
11789 @item frequency, freq, f
11790 the frequency where transform is evaluated
11791 @item timeclamp, tc
11792 value of timeclamp option
11797 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
11798 @item r(x), g(x), b(x)
11799 red, green, and blue value of intensity x
11801 Default value is @code{st(0, (midi(f)-59.5)/12);
11802 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
11803 r(1-ld(1)) + b(ld(1))}
11806 If set to 1 (the default), the video size is 1920x1080 (full HD),
11807 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
11810 Specify video fps. Default value is @code{25}.
11813 Specify number of transform per frame, so there are fps*count transforms
11814 per second. Note that audio data rate must be divisible by fps*count.
11815 Default value is @code{6}.
11819 @subsection Examples
11823 Playing audio while showing the spectrum:
11825 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
11829 Same as above, but with frame rate 30 fps:
11831 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
11835 Playing at 960x540 and lower CPU usage:
11837 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
11841 A1 and its harmonics: A1, A2, (near)E3, A3:
11843 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),
11844 asplit[a][out1]; [a] showcqt [out0]'
11848 Same as above, but with more accuracy in frequency domain (and slower):
11850 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),
11851 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
11855 B-weighting of equal loudness
11857 volume=16*b_weighting(f)
11863 tlength=100/f*tc/(100/f+tc)
11867 Custom fontcolor, C-note is colored green, others are colored blue
11869 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))'
11873 Custom gamma, now spectrum is linear to the amplitude.
11880 @section showspectrum
11882 Convert input audio to a video output, representing the audio frequency
11885 The filter accepts the following options:
11889 Specify the video size for the output. For the syntax of this option, check the
11890 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11891 Default value is @code{640x512}.
11894 Specify how the spectrum should slide along the window.
11896 It accepts the following values:
11899 the samples start again on the left when they reach the right
11901 the samples scroll from right to left
11903 frames are only produced when the samples reach the right
11906 Default value is @code{replace}.
11909 Specify display mode.
11911 It accepts the following values:
11914 all channels are displayed in the same row
11916 all channels are displayed in separate rows
11919 Default value is @samp{combined}.
11922 Specify display color mode.
11924 It accepts the following values:
11927 each channel is displayed in a separate color
11929 each channel is is displayed using the same color scheme
11932 Default value is @samp{channel}.
11935 Specify scale used for calculating intensity color values.
11937 It accepts the following values:
11942 square root, default
11949 Default value is @samp{sqrt}.
11952 Set saturation modifier for displayed colors. Negative values provide
11953 alternative color scheme. @code{0} is no saturation at all.
11954 Saturation must be in [-10.0, 10.0] range.
11955 Default value is @code{1}.
11958 Set window function.
11960 It accepts the following values:
11963 No samples pre-processing (do not expect this to be faster)
11972 Default value is @code{hann}.
11975 The usage is very similar to the showwaves filter; see the examples in that
11978 @subsection Examples
11982 Large window with logarithmic color scaling:
11984 showspectrum=s=1280x480:scale=log
11988 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
11990 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
11991 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
11997 Convert input audio to a video output, representing the samples waves.
11999 The filter accepts the following options:
12003 Specify the video size for the output. For the syntax of this option, check the
12004 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12005 Default value is @code{600x240}.
12010 Available values are:
12013 Draw a point for each sample.
12016 Draw a vertical line for each sample.
12019 Draw a point for each sample and a line between them.
12022 Draw a centered vertical line for each sample.
12025 Default value is @code{point}.
12028 Set the number of samples which are printed on the same column. A
12029 larger value will decrease the frame rate. Must be a positive
12030 integer. This option can be set only if the value for @var{rate}
12031 is not explicitly specified.
12034 Set the (approximate) output frame rate. This is done by setting the
12035 option @var{n}. Default value is "25".
12037 @item split_channels
12038 Set if channels should be drawn separately or overlap. Default value is 0.
12042 @subsection Examples
12046 Output the input file audio and the corresponding video representation
12049 amovie=a.mp3,asplit[out0],showwaves[out1]
12053 Create a synthetic signal and show it with showwaves, forcing a
12054 frame rate of 30 frames per second:
12056 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
12060 @section showwavespic
12062 Convert input audio to a single video frame, representing the samples waves.
12064 The filter accepts the following options:
12068 Specify the video size for the output. For the syntax of this option, check the
12069 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12070 Default value is @code{600x240}.
12072 @item split_channels
12073 Set if channels should be drawn separately or overlap. Default value is 0.
12076 @subsection Examples
12080 Extract a channel split representation of the wave form of a whole audio track
12081 in a 1024x800 picture using @command{ffmpeg}:
12083 ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png
12087 @section split, asplit
12089 Split input into several identical outputs.
12091 @code{asplit} works with audio input, @code{split} with video.
12093 The filter accepts a single parameter which specifies the number of outputs. If
12094 unspecified, it defaults to 2.
12096 @subsection Examples
12100 Create two separate outputs from the same input:
12102 [in] split [out0][out1]
12106 To create 3 or more outputs, you need to specify the number of
12109 [in] asplit=3 [out0][out1][out2]
12113 Create two separate outputs from the same input, one cropped and
12116 [in] split [splitout1][splitout2];
12117 [splitout1] crop=100:100:0:0 [cropout];
12118 [splitout2] pad=200:200:100:100 [padout];
12122 Create 5 copies of the input audio with @command{ffmpeg}:
12124 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
12130 Receive commands sent through a libzmq client, and forward them to
12131 filters in the filtergraph.
12133 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
12134 must be inserted between two video filters, @code{azmq} between two
12137 To enable these filters you need to install the libzmq library and
12138 headers and configure FFmpeg with @code{--enable-libzmq}.
12140 For more information about libzmq see:
12141 @url{http://www.zeromq.org/}
12143 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
12144 receives messages sent through a network interface defined by the
12145 @option{bind_address} option.
12147 The received message must be in the form:
12149 @var{TARGET} @var{COMMAND} [@var{ARG}]
12152 @var{TARGET} specifies the target of the command, usually the name of
12153 the filter class or a specific filter instance name.
12155 @var{COMMAND} specifies the name of the command for the target filter.
12157 @var{ARG} is optional and specifies the optional argument list for the
12158 given @var{COMMAND}.
12160 Upon reception, the message is processed and the corresponding command
12161 is injected into the filtergraph. Depending on the result, the filter
12162 will send a reply to the client, adopting the format:
12164 @var{ERROR_CODE} @var{ERROR_REASON}
12168 @var{MESSAGE} is optional.
12170 @subsection Examples
12172 Look at @file{tools/zmqsend} for an example of a zmq client which can
12173 be used to send commands processed by these filters.
12175 Consider the following filtergraph generated by @command{ffplay}
12177 ffplay -dumpgraph 1 -f lavfi "
12178 color=s=100x100:c=red [l];
12179 color=s=100x100:c=blue [r];
12180 nullsrc=s=200x100, zmq [bg];
12181 [bg][l] overlay [bg+l];
12182 [bg+l][r] overlay=x=100 "
12185 To change the color of the left side of the video, the following
12186 command can be used:
12188 echo Parsed_color_0 c yellow | tools/zmqsend
12191 To change the right side:
12193 echo Parsed_color_1 c pink | tools/zmqsend
12196 @c man end MULTIMEDIA FILTERS
12198 @chapter Multimedia Sources
12199 @c man begin MULTIMEDIA SOURCES
12201 Below is a description of the currently available multimedia sources.
12205 This is the same as @ref{movie} source, except it selects an audio
12211 Read audio and/or video stream(s) from a movie container.
12213 It accepts the following parameters:
12217 The name of the resource to read (not necessarily a file; it can also be a
12218 device or a stream accessed through some protocol).
12220 @item format_name, f
12221 Specifies the format assumed for the movie to read, and can be either
12222 the name of a container or an input device. If not specified, the
12223 format is guessed from @var{movie_name} or by probing.
12225 @item seek_point, sp
12226 Specifies the seek point in seconds. The frames will be output
12227 starting from this seek point. The parameter is evaluated with
12228 @code{av_strtod}, so the numerical value may be suffixed by an IS
12229 postfix. The default value is "0".
12232 Specifies the streams to read. Several streams can be specified,
12233 separated by "+". The source will then have as many outputs, in the
12234 same order. The syntax is explained in the ``Stream specifiers''
12235 section in the ffmpeg manual. Two special names, "dv" and "da" specify
12236 respectively the default (best suited) video and audio stream. Default
12237 is "dv", or "da" if the filter is called as "amovie".
12239 @item stream_index, si
12240 Specifies the index of the video stream to read. If the value is -1,
12241 the most suitable video stream will be automatically selected. The default
12242 value is "-1". Deprecated. If the filter is called "amovie", it will select
12243 audio instead of video.
12246 Specifies how many times to read the stream in sequence.
12247 If the value is less than 1, the stream will be read again and again.
12248 Default value is "1".
12250 Note that when the movie is looped the source timestamps are not
12251 changed, so it will generate non monotonically increasing timestamps.
12254 It allows overlaying a second video on top of the main input of
12255 a filtergraph, as shown in this graph:
12257 input -----------> deltapts0 --> overlay --> output
12260 movie --> scale--> deltapts1 -------+
12262 @subsection Examples
12266 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
12267 on top of the input labelled "in":
12269 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
12270 [in] setpts=PTS-STARTPTS [main];
12271 [main][over] overlay=16:16 [out]
12275 Read from a video4linux2 device, and overlay it on top of the input
12278 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
12279 [in] setpts=PTS-STARTPTS [main];
12280 [main][over] overlay=16:16 [out]
12284 Read the first video stream and the audio stream with id 0x81 from
12285 dvd.vob; the video is connected to the pad named "video" and the audio is
12286 connected to the pad named "audio":
12288 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
12292 @c man end MULTIMEDIA SOURCES