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
542 Fade in first 15 seconds of audio:
548 Fade out last 25 seconds of a 900 seconds audio:
550 afade=t=out:st=875:d=25
557 Set output format constraints for the input audio. The framework will
558 negotiate the most appropriate format to minimize conversions.
560 It accepts the following parameters:
564 A '|'-separated list of requested sample formats.
567 A '|'-separated list of requested sample rates.
569 @item channel_layouts
570 A '|'-separated list of requested channel layouts.
572 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
573 for the required syntax.
576 If a parameter is omitted, all values are allowed.
578 Force the output to either unsigned 8-bit or signed 16-bit stereo
580 aformat=sample_fmts=u8|s16:channel_layouts=stereo
585 Apply a two-pole all-pass filter with central frequency (in Hz)
586 @var{frequency}, and filter-width @var{width}.
587 An all-pass filter changes the audio's frequency to phase relationship
588 without changing its frequency to amplitude relationship.
590 The filter accepts the following options:
597 Set method to specify band-width of filter.
610 Specify the band-width of a filter in width_type units.
615 Merge two or more audio streams into a single multi-channel stream.
617 The filter accepts the following options:
622 Set the number of inputs. Default is 2.
626 If the channel layouts of the inputs are disjoint, and therefore compatible,
627 the channel layout of the output will be set accordingly and the channels
628 will be reordered as necessary. If the channel layouts of the inputs are not
629 disjoint, the output will have all the channels of the first input then all
630 the channels of the second input, in that order, and the channel layout of
631 the output will be the default value corresponding to the total number of
634 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
635 is FC+BL+BR, then the output will be in 5.1, with the channels in the
636 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
637 first input, b1 is the first channel of the second input).
639 On the other hand, if both input are in stereo, the output channels will be
640 in the default order: a1, a2, b1, b2, and the channel layout will be
641 arbitrarily set to 4.0, which may or may not be the expected value.
643 All inputs must have the same sample rate, and format.
645 If inputs do not have the same duration, the output will stop with the
652 Merge two mono files into a stereo stream:
654 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
658 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
660 ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv
666 Mixes multiple audio inputs into a single output.
668 Note that this filter only supports float samples (the @var{amerge}
669 and @var{pan} audio filters support many formats). If the @var{amix}
670 input has integer samples then @ref{aresample} will be automatically
671 inserted to perform the conversion to float samples.
675 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
677 will mix 3 input audio streams to a single output with the same duration as the
678 first input and a dropout transition time of 3 seconds.
680 It accepts the following parameters:
684 The number of inputs. If unspecified, it defaults to 2.
687 How to determine the end-of-stream.
691 The duration of the longest input. (default)
694 The duration of the shortest input.
697 The duration of the first input.
701 @item dropout_transition
702 The transition time, in seconds, for volume renormalization when an input
703 stream ends. The default value is 2 seconds.
709 Pass the audio source unchanged to the output.
713 Pad the end of an audio stream with silence.
715 This can be used together with @command{ffmpeg} @option{-shortest} to
716 extend audio streams to the same length as the video stream.
718 A description of the accepted options follows.
722 Set silence packet size. Default value is 4096.
725 Set the number of samples of silence to add to the end. After the
726 value is reached, the stream is terminated. This option is mutually
727 exclusive with @option{whole_len}.
730 Set the minimum total number of samples in the output audio stream. If
731 the value is longer than the input audio length, silence is added to
732 the end, until the value is reached. This option is mutually exclusive
733 with @option{pad_len}.
736 If neither the @option{pad_len} nor the @option{whole_len} option is
737 set, the filter will add silence to the end of the input stream
744 Add 1024 samples of silence to the end of the input:
750 Make sure the audio output will contain at least 10000 samples, pad
751 the input with silence if required:
757 Use @command{ffmpeg} to pad the audio input with silence, so that the
758 video stream will always result the shortest and will be converted
759 until the end in the output file when using the @option{shortest}
762 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
767 Add a phasing effect to the input audio.
769 A phaser filter creates series of peaks and troughs in the frequency spectrum.
770 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
772 A description of the accepted parameters follows.
776 Set input gain. Default is 0.4.
779 Set output gain. Default is 0.74
782 Set delay in milliseconds. Default is 3.0.
785 Set decay. Default is 0.4.
788 Set modulation speed in Hz. Default is 0.5.
791 Set modulation type. Default is triangular.
793 It accepts the following values:
803 Resample the input audio to the specified parameters, using the
804 libswresample library. If none are specified then the filter will
805 automatically convert between its input and output.
807 This filter is also able to stretch/squeeze the audio data to make it match
808 the timestamps or to inject silence / cut out audio to make it match the
809 timestamps, do a combination of both or do neither.
811 The filter accepts the syntax
812 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
813 expresses a sample rate and @var{resampler_options} is a list of
814 @var{key}=@var{value} pairs, separated by ":". See the
815 ffmpeg-resampler manual for the complete list of supported options.
821 Resample the input audio to 44100Hz:
827 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
828 samples per second compensation:
834 @section asetnsamples
836 Set the number of samples per each output audio frame.
838 The last output packet may contain a different number of samples, as
839 the filter will flush all the remaining samples when the input audio
842 The filter accepts the following options:
846 @item nb_out_samples, n
847 Set the number of frames per each output audio frame. The number is
848 intended as the number of samples @emph{per each channel}.
849 Default value is 1024.
852 If set to 1, the filter will pad the last audio frame with zeroes, so
853 that the last frame will contain the same number of samples as the
854 previous ones. Default value is 1.
857 For example, to set the number of per-frame samples to 1234 and
858 disable padding for the last frame, use:
860 asetnsamples=n=1234:p=0
865 Set the sample rate without altering the PCM data.
866 This will result in a change of speed and pitch.
868 The filter accepts the following options:
872 Set the output sample rate. Default is 44100 Hz.
877 Show a line containing various information for each input audio frame.
878 The input audio is not modified.
880 The shown line contains a sequence of key/value pairs of the form
881 @var{key}:@var{value}.
883 The following values are shown in the output:
887 The (sequential) number of the input frame, starting from 0.
890 The presentation timestamp of the input frame, in time base units; the time base
891 depends on the filter input pad, and is usually 1/@var{sample_rate}.
894 The presentation timestamp of the input frame in seconds.
897 position of the frame in the input stream, -1 if this information in
898 unavailable and/or meaningless (for example in case of synthetic audio)
907 The sample rate for the audio frame.
910 The number of samples (per channel) in the frame.
913 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
914 audio, the data is treated as if all the planes were concatenated.
916 @item plane_checksums
917 A list of Adler-32 checksums for each data plane.
923 Display time domain statistical information about the audio channels.
924 Statistics are calculated and displayed for each audio channel and,
925 where applicable, an overall figure is also given.
927 It accepts the following option:
930 Short window length in seconds, used for peak and trough RMS measurement.
931 Default is @code{0.05} (50 milliseconds). Allowed range is @code{[0.1 - 10]}.
934 A description of each shown parameter follows:
938 Mean amplitude displacement from zero.
941 Minimal sample level.
944 Maximal sample level.
948 Standard peak and RMS level measured in dBFS.
952 Peak and trough values for RMS level measured over a short window.
955 Standard ratio of peak to RMS level (note: not in dB).
958 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
959 (i.e. either @var{Min level} or @var{Max level}).
962 Number of occasions (not the number of samples) that the signal attained either
963 @var{Min level} or @var{Max level}.
968 Forward two audio streams and control the order the buffers are forwarded.
970 The filter accepts the following options:
974 Set the expression deciding which stream should be
975 forwarded next: if the result is negative, the first stream is forwarded; if
976 the result is positive or zero, the second stream is forwarded. It can use
977 the following variables:
981 number of buffers forwarded so far on each stream
983 number of samples forwarded so far on each stream
985 current timestamp of each stream
988 The default value is @code{t1-t2}, which means to always forward the stream
989 that has a smaller timestamp.
994 Stress-test @code{amerge} by randomly sending buffers on the wrong
995 input, while avoiding too much of a desynchronization:
997 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
998 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
1004 Synchronize audio data with timestamps by squeezing/stretching it and/or
1005 dropping samples/adding silence when needed.
1007 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1009 It accepts the following parameters:
1013 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1014 by default. When disabled, time gaps are covered with silence.
1017 The minimum difference between timestamps and audio data (in seconds) to trigger
1018 adding/dropping samples. The default value is 0.1. If you get an imperfect
1019 sync with this filter, try setting this parameter to 0.
1022 The maximum compensation in samples per second. Only relevant with compensate=1.
1023 The default value is 500.
1026 Assume that the first PTS should be this value. The time base is 1 / sample
1027 rate. This allows for padding/trimming at the start of the stream. By default,
1028 no assumption is made about the first frame's expected PTS, so no padding or
1029 trimming is done. For example, this could be set to 0 to pad the beginning with
1030 silence if an audio stream starts after the video stream or to trim any samples
1031 with a negative PTS due to encoder delay.
1039 The filter accepts exactly one parameter, the audio tempo. If not
1040 specified then the filter will assume nominal 1.0 tempo. Tempo must
1041 be in the [0.5, 2.0] range.
1043 @subsection Examples
1047 Slow down audio to 80% tempo:
1053 To speed up audio to 125% tempo:
1061 Trim the input so that the output contains one continuous subpart of the input.
1063 It accepts the following parameters:
1066 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1067 sample with the timestamp @var{start} will be the first sample in the output.
1070 Specify time of the first audio sample that will be dropped, i.e. the
1071 audio sample immediately preceding the one with the timestamp @var{end} will be
1072 the last sample in the output.
1075 Same as @var{start}, except this option sets the start timestamp in samples
1079 Same as @var{end}, except this option sets the end timestamp in samples instead
1083 The maximum duration of the output in seconds.
1086 The number of the first sample that should be output.
1089 The number of the first sample that should be dropped.
1092 @option{start}, @option{end}, and @option{duration} are expressed as time
1093 duration specifications; see
1094 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
1096 Note that the first two sets of the start/end options and the @option{duration}
1097 option look at the frame timestamp, while the _sample options simply count the
1098 samples that pass through the filter. So start/end_pts and start/end_sample will
1099 give different results when the timestamps are wrong, inexact or do not start at
1100 zero. Also note that this filter does not modify the timestamps. If you wish
1101 to have the output timestamps start at zero, insert the asetpts filter after the
1104 If multiple start or end options are set, this filter tries to be greedy and
1105 keep all samples that match at least one of the specified constraints. To keep
1106 only the part that matches all the constraints at once, chain multiple atrim
1109 The defaults are such that all the input is kept. So it is possible to set e.g.
1110 just the end values to keep everything before the specified time.
1115 Drop everything except the second minute of input:
1117 ffmpeg -i INPUT -af atrim=60:120
1121 Keep only the first 1000 samples:
1123 ffmpeg -i INPUT -af atrim=end_sample=1000
1130 Apply a two-pole Butterworth band-pass filter with central
1131 frequency @var{frequency}, and (3dB-point) band-width width.
1132 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1133 instead of the default: constant 0dB peak gain.
1134 The filter roll off at 6dB per octave (20dB per decade).
1136 The filter accepts the following options:
1140 Set the filter's central frequency. Default is @code{3000}.
1143 Constant skirt gain if set to 1. Defaults to 0.
1146 Set method to specify band-width of filter.
1159 Specify the band-width of a filter in width_type units.
1164 Apply a two-pole Butterworth band-reject filter with central
1165 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1166 The filter roll off at 6dB per octave (20dB per decade).
1168 The filter accepts the following options:
1172 Set the filter's central frequency. Default is @code{3000}.
1175 Set method to specify band-width of filter.
1188 Specify the band-width of a filter in width_type units.
1193 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1194 shelving filter with a response similar to that of a standard
1195 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1197 The filter accepts the following options:
1201 Give the gain at 0 Hz. Its useful range is about -20
1202 (for a large cut) to +20 (for a large boost).
1203 Beware of clipping when using a positive gain.
1206 Set the filter's central frequency and so can be used
1207 to extend or reduce the frequency range to be boosted or cut.
1208 The default value is @code{100} Hz.
1211 Set method to specify band-width of filter.
1224 Determine how steep is the filter's shelf transition.
1229 Apply a biquad IIR filter with the given coefficients.
1230 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1231 are the numerator and denominator coefficients respectively.
1234 Bauer stereo to binaural transformation, which improves headphone listening of
1235 stereo audio records.
1237 It accepts the following parameters:
1241 Pre-defined crossfeed level.
1245 Default level (fcut=700, feed=50).
1248 Chu Moy circuit (fcut=700, feed=60).
1251 Jan Meier circuit (fcut=650, feed=95).
1256 Cut frequency (in Hz).
1265 Remap input channels to new locations.
1267 It accepts the following parameters:
1269 @item channel_layout
1270 The channel layout of the output stream.
1273 Map channels from input to output. The argument is a '|'-separated list of
1274 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1275 @var{in_channel} form. @var{in_channel} can be either the name of the input
1276 channel (e.g. FL for front left) or its index in the input channel layout.
1277 @var{out_channel} is the name of the output channel or its index in the output
1278 channel layout. If @var{out_channel} is not given then it is implicitly an
1279 index, starting with zero and increasing by one for each mapping.
1282 If no mapping is present, the filter will implicitly map input channels to
1283 output channels, preserving indices.
1285 For example, assuming a 5.1+downmix input MOV file,
1287 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1289 will create an output WAV file tagged as stereo from the downmix channels of
1292 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1294 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1297 @section channelsplit
1299 Split each channel from an input audio stream into a separate output stream.
1301 It accepts the following parameters:
1303 @item channel_layout
1304 The channel layout of the input stream. The default is "stereo".
1307 For example, assuming a stereo input MP3 file,
1309 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1311 will create an output Matroska file with two audio streams, one containing only
1312 the left channel and the other the right channel.
1314 Split a 5.1 WAV file into per-channel files:
1316 ffmpeg -i in.wav -filter_complex
1317 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1318 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1319 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1324 Compress or expand the audio's dynamic range.
1326 It accepts the following parameters:
1332 A list of times in seconds for each channel over which the instantaneous level
1333 of the input signal is averaged to determine its volume. @var{attacks} refers to
1334 increase of volume and @var{decays} refers to decrease of volume. For most
1335 situations, the attack time (response to the audio getting louder) should be
1336 shorter than the decay time, because the human ear is more sensitive to sudden
1337 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1338 a typical value for decay is 0.8 seconds.
1341 A list of points for the transfer function, specified in dB relative to the
1342 maximum possible signal amplitude. Each key points list must be defined using
1343 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1344 @code{x0/y0 x1/y1 x2/y2 ....}
1346 The input values must be in strictly increasing order but the transfer function
1347 does not have to be monotonically rising. The point @code{0/0} is assumed but
1348 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1349 function are @code{-70/-70|-60/-20}.
1352 Set the curve radius in dB for all joints. It defaults to 0.01.
1355 Set the additional gain in dB to be applied at all points on the transfer
1356 function. This allows for easy adjustment of the overall gain.
1360 Set an initial volume, in dB, to be assumed for each channel when filtering
1361 starts. This permits the user to supply a nominal level initially, so that, for
1362 example, a very large gain is not applied to initial signal levels before the
1363 companding has begun to operate. A typical value for audio which is initially
1364 quiet is -90 dB. It defaults to 0.
1367 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1368 delayed before being fed to the volume adjuster. Specifying a delay
1369 approximately equal to the attack/decay times allows the filter to effectively
1370 operate in predictive rather than reactive mode. It defaults to 0.
1374 @subsection Examples
1378 Make music with both quiet and loud passages suitable for listening to in a
1381 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1385 A noise gate for when the noise is at a lower level than the signal:
1387 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1391 Here is another noise gate, this time for when the noise is at a higher level
1392 than the signal (making it, in some ways, similar to squelch):
1394 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1399 Apply a DC shift to the audio.
1401 This can be useful to remove a DC offset (caused perhaps by a hardware problem
1402 in the recording chain) from the audio. The effect of a DC offset is reduced
1403 headroom and hence volume. The @ref{astats} filter can be used to determine if
1404 a signal has a DC offset.
1408 Set the DC shift, allowed range is [-1, 1]. It indicates the amount to shift
1412 Optional. It should have a value much less than 1 (e.g. 0.05 or 0.02) and is
1413 used to prevent clipping.
1418 Make audio easier to listen to on headphones.
1420 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1421 so that when listened to on headphones the stereo image is moved from
1422 inside your head (standard for headphones) to outside and in front of
1423 the listener (standard for speakers).
1429 Apply a two-pole peaking equalisation (EQ) filter. With this
1430 filter, the signal-level at and around a selected frequency can
1431 be increased or decreased, whilst (unlike bandpass and bandreject
1432 filters) that at all other frequencies is unchanged.
1434 In order to produce complex equalisation curves, this filter can
1435 be given several times, each with a different central frequency.
1437 The filter accepts the following options:
1441 Set the filter's central frequency in Hz.
1444 Set method to specify band-width of filter.
1457 Specify the band-width of a filter in width_type units.
1460 Set the required gain or attenuation in dB.
1461 Beware of clipping when using a positive gain.
1464 @subsection Examples
1467 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1469 equalizer=f=1000:width_type=h:width=200:g=-10
1473 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1475 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1480 Apply a flanging effect to the audio.
1482 The filter accepts the following options:
1486 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
1489 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
1492 Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
1496 Set percentage of delayed signal mixed with original. Range from 0 to 100.
1497 Default value is 71.
1500 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
1503 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
1504 Default value is @var{sinusoidal}.
1507 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
1508 Default value is 25.
1511 Set delay-line interpolation, @var{linear} or @var{quadratic}.
1512 Default is @var{linear}.
1517 Apply a high-pass filter with 3dB point frequency.
1518 The filter can be either single-pole, or double-pole (the default).
1519 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1521 The filter accepts the following options:
1525 Set frequency in Hz. Default is 3000.
1528 Set number of poles. Default is 2.
1531 Set method to specify band-width of filter.
1544 Specify the band-width of a filter in width_type units.
1545 Applies only to double-pole filter.
1546 The default is 0.707q and gives a Butterworth response.
1551 Join multiple input streams into one multi-channel stream.
1553 It accepts the following parameters:
1557 The number of input streams. It defaults to 2.
1559 @item channel_layout
1560 The desired output channel layout. It defaults to stereo.
1563 Map channels from inputs to output. The argument is a '|'-separated list of
1564 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1565 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1566 can be either the name of the input channel (e.g. FL for front left) or its
1567 index in the specified input stream. @var{out_channel} is the name of the output
1571 The filter will attempt to guess the mappings when they are not specified
1572 explicitly. It does so by first trying to find an unused matching input channel
1573 and if that fails it picks the first unused input channel.
1575 Join 3 inputs (with properly set channel layouts):
1577 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1580 Build a 5.1 output from 6 single-channel streams:
1582 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1583 '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'
1589 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1591 To enable compilation of this filter you need to configure FFmpeg with
1592 @code{--enable-ladspa}.
1596 Specifies the name of LADSPA plugin library to load. If the environment
1597 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1598 each one of the directories specified by the colon separated list in
1599 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1600 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1601 @file{/usr/lib/ladspa/}.
1604 Specifies the plugin within the library. Some libraries contain only
1605 one plugin, but others contain many of them. If this is not set filter
1606 will list all available plugins within the specified library.
1609 Set the '|' separated list of controls which are zero or more floating point
1610 values that determine the behavior of the loaded plugin (for example delay,
1612 Controls need to be defined using the following syntax:
1613 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1614 @var{valuei} is the value set on the @var{i}-th control.
1615 If @option{controls} is set to @code{help}, all available controls and
1616 their valid ranges are printed.
1618 @item sample_rate, s
1619 Specify the sample rate, default to 44100. Only used if plugin have
1623 Set the number of samples per channel per each output frame, default
1624 is 1024. Only used if plugin have zero inputs.
1627 Set the minimum duration of the sourced audio. See
1628 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
1629 for the accepted syntax.
1630 Note that the resulting duration may be greater than the specified duration,
1631 as the generated audio is always cut at the end of a complete frame.
1632 If not specified, or the expressed duration is negative, the audio is
1633 supposed to be generated forever.
1634 Only used if plugin have zero inputs.
1638 @subsection Examples
1642 List all available plugins within amp (LADSPA example plugin) library:
1648 List all available controls and their valid ranges for @code{vcf_notch}
1649 plugin from @code{VCF} library:
1651 ladspa=f=vcf:p=vcf_notch:c=help
1655 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1658 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1662 Add reverberation to the audio using TAP-plugins
1663 (Tom's Audio Processing plugins):
1665 ladspa=file=tap_reverb:tap_reverb
1669 Generate white noise, with 0.2 amplitude:
1671 ladspa=file=cmt:noise_source_white:c=c0=.2
1675 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1676 @code{C* Audio Plugin Suite} (CAPS) library:
1678 ladspa=file=caps:Click:c=c1=20'
1682 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1684 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1688 @subsection Commands
1690 This filter supports the following commands:
1693 Modify the @var{N}-th control value.
1695 If the specified value is not valid, it is ignored and prior one is kept.
1700 Apply a low-pass filter with 3dB point frequency.
1701 The filter can be either single-pole or double-pole (the default).
1702 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1704 The filter accepts the following options:
1708 Set frequency in Hz. Default is 500.
1711 Set number of poles. Default is 2.
1714 Set method to specify band-width of filter.
1727 Specify the band-width of a filter in width_type units.
1728 Applies only to double-pole filter.
1729 The default is 0.707q and gives a Butterworth response.
1734 Mix channels with specific gain levels. The filter accepts the output
1735 channel layout followed by a set of channels definitions.
1737 This filter is also designed to efficiently remap the channels of an audio
1740 The filter accepts parameters of the form:
1741 "@var{l}|@var{outdef}|@var{outdef}|..."
1745 output channel layout or number of channels
1748 output channel specification, of the form:
1749 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1752 output channel to define, either a channel name (FL, FR, etc.) or a channel
1753 number (c0, c1, etc.)
1756 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1759 input channel to use, see out_name for details; it is not possible to mix
1760 named and numbered input channels
1763 If the `=' in a channel specification is replaced by `<', then the gains for
1764 that specification will be renormalized so that the total is 1, thus
1765 avoiding clipping noise.
1767 @subsection Mixing examples
1769 For example, if you want to down-mix from stereo to mono, but with a bigger
1770 factor for the left channel:
1772 pan=1c|c0=0.9*c0+0.1*c1
1775 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1776 7-channels surround:
1778 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1781 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1782 that should be preferred (see "-ac" option) unless you have very specific
1785 @subsection Remapping examples
1787 The channel remapping will be effective if, and only if:
1790 @item gain coefficients are zeroes or ones,
1791 @item only one input per channel output,
1794 If all these conditions are satisfied, the filter will notify the user ("Pure
1795 channel mapping detected"), and use an optimized and lossless method to do the
1798 For example, if you have a 5.1 source and want a stereo audio stream by
1799 dropping the extra channels:
1801 pan="stereo| c0=FL | c1=FR"
1804 Given the same source, you can also switch front left and front right channels
1805 and keep the input channel layout:
1807 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
1810 If the input is a stereo audio stream, you can mute the front left channel (and
1811 still keep the stereo channel layout) with:
1816 Still with a stereo audio stream input, you can copy the right channel in both
1817 front left and right:
1819 pan="stereo| c0=FR | c1=FR"
1824 ReplayGain scanner filter. This filter takes an audio stream as an input and
1825 outputs it unchanged.
1826 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1830 Convert the audio sample format, sample rate and channel layout. It is
1831 not meant to be used directly.
1833 @section silencedetect
1835 Detect silence in an audio stream.
1837 This filter logs a message when it detects that the input audio volume is less
1838 or equal to a noise tolerance value for a duration greater or equal to the
1839 minimum detected noise duration.
1841 The printed times and duration are expressed in seconds.
1843 The filter accepts the following options:
1847 Set silence duration until notification (default is 2 seconds).
1850 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1851 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1854 @subsection Examples
1858 Detect 5 seconds of silence with -50dB noise tolerance:
1860 silencedetect=n=-50dB:d=5
1864 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1865 tolerance in @file{silence.mp3}:
1867 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1871 @section silenceremove
1873 Remove silence from the beginning, middle or end of the audio.
1875 The filter accepts the following options:
1879 This value is used to indicate if audio should be trimmed at beginning of
1880 the audio. A value of zero indicates no silence should be trimmed from the
1881 beginning. When specifying a non-zero value, it trims audio up until it
1882 finds non-silence. Normally, when trimming silence from beginning of audio
1883 the @var{start_periods} will be @code{1} but it can be increased to higher
1884 values to trim all audio up to specific count of non-silence periods.
1885 Default value is @code{0}.
1887 @item start_duration
1888 Specify the amount of time that non-silence must be detected before it stops
1889 trimming audio. By increasing the duration, bursts of noises can be treated
1890 as silence and trimmed off. Default value is @code{0}.
1892 @item start_threshold
1893 This indicates what sample value should be treated as silence. For digital
1894 audio, a value of @code{0} may be fine but for audio recorded from analog,
1895 you may wish to increase the value to account for background noise.
1896 Can be specified in dB (in case "dB" is appended to the specified value)
1897 or amplitude ratio. Default value is @code{0}.
1900 Set the count for trimming silence from the end of audio.
1901 To remove silence from the middle of a file, specify a @var{stop_periods}
1902 that is negative. This value is then treated as a positive value and is
1903 used to indicate the effect should restart processing as specified by
1904 @var{start_periods}, making it suitable for removing periods of silence
1905 in the middle of the audio.
1906 Default value is @code{0}.
1909 Specify a duration of silence that must exist before audio is not copied any
1910 more. By specifying a higher duration, silence that is wanted can be left in
1912 Default value is @code{0}.
1914 @item stop_threshold
1915 This is the same as @option{start_threshold} but for trimming silence from
1917 Can be specified in dB (in case "dB" is appended to the specified value)
1918 or amplitude ratio. Default value is @code{0}.
1921 This indicate that @var{stop_duration} length of audio should be left intact
1922 at the beginning of each period of silence.
1923 For example, if you want to remove long pauses between words but do not want
1924 to remove the pauses completely. Default value is @code{0}.
1928 @subsection Examples
1932 The following example shows how this filter can be used to start a recording
1933 that does not contain the delay at the start which usually occurs between
1934 pressing the record button and the start of the performance:
1936 silenceremove=1:5:0.02
1942 Boost or cut treble (upper) frequencies of the audio using a two-pole
1943 shelving filter with a response similar to that of a standard
1944 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1946 The filter accepts the following options:
1950 Give the gain at whichever is the lower of ~22 kHz and the
1951 Nyquist frequency. Its useful range is about -20 (for a large cut)
1952 to +20 (for a large boost). Beware of clipping when using a positive gain.
1955 Set the filter's central frequency and so can be used
1956 to extend or reduce the frequency range to be boosted or cut.
1957 The default value is @code{3000} Hz.
1960 Set method to specify band-width of filter.
1973 Determine how steep is the filter's shelf transition.
1978 Adjust the input audio volume.
1980 It accepts the following parameters:
1984 Set audio volume expression.
1986 Output values are clipped to the maximum value.
1988 The output audio volume is given by the relation:
1990 @var{output_volume} = @var{volume} * @var{input_volume}
1993 The default value for @var{volume} is "1.0".
1996 This parameter represents the mathematical precision.
1998 It determines which input sample formats will be allowed, which affects the
1999 precision of the volume scaling.
2003 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
2005 32-bit floating-point; this limits input sample format to FLT. (default)
2007 64-bit floating-point; this limits input sample format to DBL.
2011 Choose the behaviour on encountering ReplayGain side data in input frames.
2015 Remove ReplayGain side data, ignoring its contents (the default).
2018 Ignore ReplayGain side data, but leave it in the frame.
2021 Prefer the track gain, if present.
2024 Prefer the album gain, if present.
2027 @item replaygain_preamp
2028 Pre-amplification gain in dB to apply to the selected replaygain gain.
2030 Default value for @var{replaygain_preamp} is 0.0.
2033 Set when the volume expression is evaluated.
2035 It accepts the following values:
2038 only evaluate expression once during the filter initialization, or
2039 when the @samp{volume} command is sent
2042 evaluate expression for each incoming frame
2045 Default value is @samp{once}.
2048 The volume expression can contain the following parameters.
2052 frame number (starting at zero)
2055 @item nb_consumed_samples
2056 number of samples consumed by the filter
2058 number of samples in the current frame
2060 original frame position in the file
2066 PTS at start of stream
2068 time at start of stream
2074 last set volume value
2077 Note that when @option{eval} is set to @samp{once} only the
2078 @var{sample_rate} and @var{tb} variables are available, all other
2079 variables will evaluate to NAN.
2081 @subsection Commands
2083 This filter supports the following commands:
2086 Modify the volume expression.
2087 The command accepts the same syntax of the corresponding option.
2089 If the specified expression is not valid, it is kept at its current
2091 @item replaygain_noclip
2092 Prevent clipping by limiting the gain applied.
2094 Default value for @var{replaygain_noclip} is 1.
2098 @subsection Examples
2102 Halve the input audio volume:
2106 volume=volume=-6.0206dB
2109 In all the above example the named key for @option{volume} can be
2110 omitted, for example like in:
2116 Increase input audio power by 6 decibels using fixed-point precision:
2118 volume=volume=6dB:precision=fixed
2122 Fade volume after time 10 with an annihilation period of 5 seconds:
2124 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
2128 @section volumedetect
2130 Detect the volume of the input video.
2132 The filter has no parameters. The input is not modified. Statistics about
2133 the volume will be printed in the log when the input stream end is reached.
2135 In particular it will show the mean volume (root mean square), maximum
2136 volume (on a per-sample basis), and the beginning of a histogram of the
2137 registered volume values (from the maximum value to a cumulated 1/1000 of
2140 All volumes are in decibels relative to the maximum PCM value.
2142 @subsection Examples
2144 Here is an excerpt of the output:
2146 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2147 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2148 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2149 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2150 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2151 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2152 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2153 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2154 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2160 The mean square energy is approximately -27 dB, or 10^-2.7.
2162 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2164 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2167 In other words, raising the volume by +4 dB does not cause any clipping,
2168 raising it by +5 dB causes clipping for 6 samples, etc.
2170 @c man end AUDIO FILTERS
2172 @chapter Audio Sources
2173 @c man begin AUDIO SOURCES
2175 Below is a description of the currently available audio sources.
2179 Buffer audio frames, and make them available to the filter chain.
2181 This source is mainly intended for a programmatic use, in particular
2182 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2184 It accepts the following parameters:
2188 The timebase which will be used for timestamps of submitted frames. It must be
2189 either a floating-point number or in @var{numerator}/@var{denominator} form.
2192 The sample rate of the incoming audio buffers.
2195 The sample format of the incoming audio buffers.
2196 Either a sample format name or its corresponding integer representation from
2197 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2199 @item channel_layout
2200 The channel layout of the incoming audio buffers.
2201 Either a channel layout name from channel_layout_map in
2202 @file{libavutil/channel_layout.c} or its corresponding integer representation
2203 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2206 The number of channels of the incoming audio buffers.
2207 If both @var{channels} and @var{channel_layout} are specified, then they
2212 @subsection Examples
2215 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2218 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2219 Since the sample format with name "s16p" corresponds to the number
2220 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2223 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2228 Generate an audio signal specified by an expression.
2230 This source accepts in input one or more expressions (one for each
2231 channel), which are evaluated and used to generate a corresponding
2234 This source accepts the following options:
2238 Set the '|'-separated expressions list for each separate channel. In case the
2239 @option{channel_layout} option is not specified, the selected channel layout
2240 depends on the number of provided expressions. Otherwise the last
2241 specified expression is applied to the remaining output channels.
2243 @item channel_layout, c
2244 Set the channel layout. The number of channels in the specified layout
2245 must be equal to the number of specified expressions.
2248 Set the minimum duration of the sourced audio. See
2249 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2250 for the accepted syntax.
2251 Note that the resulting duration may be greater than the specified
2252 duration, as the generated audio is always cut at the end of a
2255 If not specified, or the expressed duration is negative, the audio is
2256 supposed to be generated forever.
2259 Set the number of samples per channel per each output frame,
2262 @item sample_rate, s
2263 Specify the sample rate, default to 44100.
2266 Each expression in @var{exprs} can contain the following constants:
2270 number of the evaluated sample, starting from 0
2273 time of the evaluated sample expressed in seconds, starting from 0
2280 @subsection Examples
2290 Generate a sin signal with frequency of 440 Hz, set sample rate to
2293 aevalsrc="sin(440*2*PI*t):s=8000"
2297 Generate a two channels signal, specify the channel layout (Front
2298 Center + Back Center) explicitly:
2300 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2304 Generate white noise:
2306 aevalsrc="-2+random(0)"
2310 Generate an amplitude modulated signal:
2312 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2316 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2318 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2325 The null audio source, return unprocessed audio frames. It is mainly useful
2326 as a template and to be employed in analysis / debugging tools, or as
2327 the source for filters which ignore the input data (for example the sox
2330 This source accepts the following options:
2334 @item channel_layout, cl
2336 Specifies the channel layout, and can be either an integer or a string
2337 representing a channel layout. The default value of @var{channel_layout}
2340 Check the channel_layout_map definition in
2341 @file{libavutil/channel_layout.c} for the mapping between strings and
2342 channel layout values.
2344 @item sample_rate, r
2345 Specifies the sample rate, and defaults to 44100.
2348 Set the number of samples per requested frames.
2352 @subsection Examples
2356 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2358 anullsrc=r=48000:cl=4
2362 Do the same operation with a more obvious syntax:
2364 anullsrc=r=48000:cl=mono
2368 All the parameters need to be explicitly defined.
2372 Synthesize a voice utterance using the libflite library.
2374 To enable compilation of this filter you need to configure FFmpeg with
2375 @code{--enable-libflite}.
2377 Note that the flite library is not thread-safe.
2379 The filter accepts the following options:
2384 If set to 1, list the names of the available voices and exit
2385 immediately. Default value is 0.
2388 Set the maximum number of samples per frame. Default value is 512.
2391 Set the filename containing the text to speak.
2394 Set the text to speak.
2397 Set the voice to use for the speech synthesis. Default value is
2398 @code{kal}. See also the @var{list_voices} option.
2401 @subsection Examples
2405 Read from file @file{speech.txt}, and synthesize the text using the
2406 standard flite voice:
2408 flite=textfile=speech.txt
2412 Read the specified text selecting the @code{slt} voice:
2414 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2418 Input text to ffmpeg:
2420 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2424 Make @file{ffplay} speak the specified text, using @code{flite} and
2425 the @code{lavfi} device:
2427 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2431 For more information about libflite, check:
2432 @url{http://www.speech.cs.cmu.edu/flite/}
2436 Generate an audio signal made of a sine wave with amplitude 1/8.
2438 The audio signal is bit-exact.
2440 The filter accepts the following options:
2445 Set the carrier frequency. Default is 440 Hz.
2447 @item beep_factor, b
2448 Enable a periodic beep every second with frequency @var{beep_factor} times
2449 the carrier frequency. Default is 0, meaning the beep is disabled.
2451 @item sample_rate, r
2452 Specify the sample rate, default is 44100.
2455 Specify the duration of the generated audio stream.
2457 @item samples_per_frame
2458 Set the number of samples per output frame, default is 1024.
2461 @subsection Examples
2466 Generate a simple 440 Hz sine wave:
2472 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2476 sine=frequency=220:beep_factor=4:duration=5
2481 @c man end AUDIO SOURCES
2483 @chapter Audio Sinks
2484 @c man begin AUDIO SINKS
2486 Below is a description of the currently available audio sinks.
2488 @section abuffersink
2490 Buffer audio frames, and make them available to the end of filter chain.
2492 This sink is mainly intended for programmatic use, in particular
2493 through the interface defined in @file{libavfilter/buffersink.h}
2494 or the options system.
2496 It accepts a pointer to an AVABufferSinkContext structure, which
2497 defines the incoming buffers' formats, to be passed as the opaque
2498 parameter to @code{avfilter_init_filter} for initialization.
2501 Null audio sink; do absolutely nothing with the input audio. It is
2502 mainly useful as a template and for use in analysis / debugging
2505 @c man end AUDIO SINKS
2507 @chapter Video Filters
2508 @c man begin VIDEO FILTERS
2510 When you configure your FFmpeg build, you can disable any of the
2511 existing filters using @code{--disable-filters}.
2512 The configure output will show the video filters included in your
2515 Below is a description of the currently available video filters.
2517 @section alphaextract
2519 Extract the alpha component from the input as a grayscale video. This
2520 is especially useful with the @var{alphamerge} filter.
2524 Add or replace the alpha component of the primary input with the
2525 grayscale value of a second input. This is intended for use with
2526 @var{alphaextract} to allow the transmission or storage of frame
2527 sequences that have alpha in a format that doesn't support an alpha
2530 For example, to reconstruct full frames from a normal YUV-encoded video
2531 and a separate video created with @var{alphaextract}, you might use:
2533 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2536 Since this filter is designed for reconstruction, it operates on frame
2537 sequences without considering timestamps, and terminates when either
2538 input reaches end of stream. This will cause problems if your encoding
2539 pipeline drops frames. If you're trying to apply an image as an
2540 overlay to a video stream, consider the @var{overlay} filter instead.
2544 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2545 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2546 Substation Alpha) subtitles files.
2548 This filter accepts the following option in addition to the common options from
2549 the @ref{subtitles} filter:
2553 Set the shaping engine
2555 Available values are:
2558 The default libass shaping engine, which is the best available.
2560 Fast, font-agnostic shaper that can do only substitutions
2562 Slower shaper using OpenType for substitutions and positioning
2565 The default is @code{auto}.
2570 Compute the bounding box for the non-black pixels in the input frame
2573 This filter computes the bounding box containing all the pixels with a
2574 luminance value greater than the minimum allowed value.
2575 The parameters describing the bounding box are printed on the filter
2578 The filter accepts the following option:
2582 Set the minimal luminance value. Default is @code{16}.
2585 @section blackdetect
2587 Detect video intervals that are (almost) completely black. Can be
2588 useful to detect chapter transitions, commercials, or invalid
2589 recordings. Output lines contains the time for the start, end and
2590 duration of the detected black interval expressed in seconds.
2592 In order to display the output lines, you need to set the loglevel at
2593 least to the AV_LOG_INFO value.
2595 The filter accepts the following options:
2598 @item black_min_duration, d
2599 Set the minimum detected black duration expressed in seconds. It must
2600 be a non-negative floating point number.
2602 Default value is 2.0.
2604 @item picture_black_ratio_th, pic_th
2605 Set the threshold for considering a picture "black".
2606 Express the minimum value for the ratio:
2608 @var{nb_black_pixels} / @var{nb_pixels}
2611 for which a picture is considered black.
2612 Default value is 0.98.
2614 @item pixel_black_th, pix_th
2615 Set the threshold for considering a pixel "black".
2617 The threshold expresses the maximum pixel luminance value for which a
2618 pixel is considered "black". The provided value is scaled according to
2619 the following equation:
2621 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2624 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2625 the input video format, the range is [0-255] for YUV full-range
2626 formats and [16-235] for YUV non full-range formats.
2628 Default value is 0.10.
2631 The following example sets the maximum pixel threshold to the minimum
2632 value, and detects only black intervals of 2 or more seconds:
2634 blackdetect=d=2:pix_th=0.00
2639 Detect frames that are (almost) completely black. Can be useful to
2640 detect chapter transitions or commercials. Output lines consist of
2641 the frame number of the detected frame, the percentage of blackness,
2642 the position in the file if known or -1 and the timestamp in seconds.
2644 In order to display the output lines, you need to set the loglevel at
2645 least to the AV_LOG_INFO value.
2647 It accepts the following parameters:
2652 The percentage of the pixels that have to be below the threshold; it defaults to
2655 @item threshold, thresh
2656 The threshold below which a pixel value is considered black; it defaults to
2661 @section blend, tblend
2663 Blend two video frames into each other.
2665 The @code{blend} filter takes two input streams and outputs one
2666 stream, the first input is the "top" layer and second input is
2667 "bottom" layer. Output terminates when shortest input terminates.
2669 The @code{tblend} (time blend) filter takes two consecutive frames
2670 from one single stream, and outputs the result obtained by blending
2671 the new frame on top of the old frame.
2673 A description of the accepted options follows.
2681 Set blend mode for specific pixel component or all pixel components in case
2682 of @var{all_mode}. Default value is @code{normal}.
2684 Available values for component modes are:
2718 Set blend opacity for specific pixel component or all pixel components in case
2719 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2726 Set blend expression for specific pixel component or all pixel components in case
2727 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2729 The expressions can use the following variables:
2733 The sequential number of the filtered frame, starting from @code{0}.
2737 the coordinates of the current sample
2741 the width and height of currently filtered plane
2745 Width and height scale depending on the currently filtered plane. It is the
2746 ratio between the corresponding luma plane number of pixels and the current
2747 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2748 @code{0.5,0.5} for chroma planes.
2751 Time of the current frame, expressed in seconds.
2754 Value of pixel component at current location for first video frame (top layer).
2757 Value of pixel component at current location for second video frame (bottom layer).
2761 Force termination when the shortest input terminates. Default is
2762 @code{0}. This option is only defined for the @code{blend} filter.
2765 Continue applying the last bottom frame after the end of the stream. A value of
2766 @code{0} disable the filter after the last frame of the bottom layer is reached.
2767 Default is @code{1}. This option is only defined for the @code{blend} filter.
2770 @subsection Examples
2774 Apply transition from bottom layer to top layer in first 10 seconds:
2776 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2780 Apply 1x1 checkerboard effect:
2782 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2786 Apply uncover left effect:
2788 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2792 Apply uncover down effect:
2794 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2798 Apply uncover up-left effect:
2800 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2804 Display differences between the current and the previous frame:
2806 tblend=all_mode=difference128
2812 Apply a boxblur algorithm to the input video.
2814 It accepts the following parameters:
2818 @item luma_radius, lr
2819 @item luma_power, lp
2820 @item chroma_radius, cr
2821 @item chroma_power, cp
2822 @item alpha_radius, ar
2823 @item alpha_power, ap
2827 A description of the accepted options follows.
2830 @item luma_radius, lr
2831 @item chroma_radius, cr
2832 @item alpha_radius, ar
2833 Set an expression for the box radius in pixels used for blurring the
2834 corresponding input plane.
2836 The radius value must be a non-negative number, and must not be
2837 greater than the value of the expression @code{min(w,h)/2} for the
2838 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2841 Default value for @option{luma_radius} is "2". If not specified,
2842 @option{chroma_radius} and @option{alpha_radius} default to the
2843 corresponding value set for @option{luma_radius}.
2845 The expressions can contain the following constants:
2849 The input width and height in pixels.
2853 The input chroma image width and height in pixels.
2857 The horizontal and vertical chroma subsample values. For example, for the
2858 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
2861 @item luma_power, lp
2862 @item chroma_power, cp
2863 @item alpha_power, ap
2864 Specify how many times the boxblur filter is applied to the
2865 corresponding plane.
2867 Default value for @option{luma_power} is 2. If not specified,
2868 @option{chroma_power} and @option{alpha_power} default to the
2869 corresponding value set for @option{luma_power}.
2871 A value of 0 will disable the effect.
2874 @subsection Examples
2878 Apply a boxblur filter with the luma, chroma, and alpha radii
2881 boxblur=luma_radius=2:luma_power=1
2886 Set the luma radius to 2, and alpha and chroma radius to 0:
2888 boxblur=2:1:cr=0:ar=0
2892 Set the luma and chroma radii to a fraction of the video dimension:
2894 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2900 Visualize information exported by some codecs.
2902 Some codecs can export information through frames using side-data or other
2903 means. For example, some MPEG based codecs export motion vectors through the
2904 @var{export_mvs} flag in the codec @option{flags2} option.
2906 The filter accepts the following option:
2910 Set motion vectors to visualize.
2912 Available flags for @var{mv} are:
2916 forward predicted MVs of P-frames
2918 forward predicted MVs of B-frames
2920 backward predicted MVs of B-frames
2924 @subsection Examples
2928 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
2930 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
2934 @section colorbalance
2935 Modify intensity of primary colors (red, green and blue) of input frames.
2937 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2938 regions for the red-cyan, green-magenta or blue-yellow balance.
2940 A positive adjustment value shifts the balance towards the primary color, a negative
2941 value towards the complementary color.
2943 The filter accepts the following options:
2949 Adjust red, green and blue shadows (darkest pixels).
2954 Adjust red, green and blue midtones (medium pixels).
2959 Adjust red, green and blue highlights (brightest pixels).
2961 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2964 @subsection Examples
2968 Add red color cast to shadows:
2974 @section colorlevels
2976 Adjust video input frames using levels.
2978 The filter accepts the following options:
2985 Adjust red, green, blue and alpha input black point.
2986 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2992 Adjust red, green, blue and alpha input white point.
2993 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
2995 Input levels are used to lighten highlights (bright tones), darken shadows
2996 (dark tones), change the balance of bright and dark tones.
3002 Adjust red, green, blue and alpha output black point.
3003 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
3009 Adjust red, green, blue and alpha output white point.
3010 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
3012 Output levels allows manual selection of a constrained output level range.
3015 @subsection Examples
3019 Make video output darker:
3021 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
3027 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
3031 Make video output lighter:
3033 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
3037 Increase brightness:
3039 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
3043 @section colorchannelmixer
3045 Adjust video input frames by re-mixing color channels.
3047 This filter modifies a color channel by adding the values associated to
3048 the other channels of the same pixels. For example if the value to
3049 modify is red, the output value will be:
3051 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
3054 The filter accepts the following options:
3061 Adjust contribution of input red, green, blue and alpha channels for output red channel.
3062 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
3068 Adjust contribution of input red, green, blue and alpha channels for output green channel.
3069 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
3075 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
3076 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
3082 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
3083 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
3085 Allowed ranges for options are @code{[-2.0, 2.0]}.
3088 @subsection Examples
3092 Convert source to grayscale:
3094 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
3097 Simulate sepia tones:
3099 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
3103 @section colormatrix
3105 Convert color matrix.
3107 The filter accepts the following options:
3112 Specify the source and destination color matrix. Both values must be
3115 The accepted values are:
3131 For example to convert from BT.601 to SMPTE-240M, use the command:
3133 colormatrix=bt601:smpte240m
3138 Copy the input source unchanged to the output. This is mainly useful for
3143 Crop the input video to given dimensions.
3145 It accepts the following parameters:
3149 The width of the output video. It defaults to @code{iw}.
3150 This expression is evaluated only once during the filter
3154 The height of the output video. It defaults to @code{ih}.
3155 This expression is evaluated only once during the filter
3159 The horizontal position, in the input video, of the left edge of the output
3160 video. It defaults to @code{(in_w-out_w)/2}.
3161 This expression is evaluated per-frame.
3164 The vertical position, in the input video, of the top edge of the output video.
3165 It defaults to @code{(in_h-out_h)/2}.
3166 This expression is evaluated per-frame.
3169 If set to 1 will force the output display aspect ratio
3170 to be the same of the input, by changing the output sample aspect
3171 ratio. It defaults to 0.
3174 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
3175 expressions containing the following constants:
3180 The computed values for @var{x} and @var{y}. They are evaluated for
3185 The input width and height.
3189 These are the same as @var{in_w} and @var{in_h}.
3193 The output (cropped) width and height.
3197 These are the same as @var{out_w} and @var{out_h}.
3200 same as @var{iw} / @var{ih}
3203 input sample aspect ratio
3206 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
3210 horizontal and vertical chroma subsample values. For example for the
3211 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3214 The number of the input frame, starting from 0.
3217 the position in the file of the input frame, NAN if unknown
3220 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
3224 The expression for @var{out_w} may depend on the value of @var{out_h},
3225 and the expression for @var{out_h} may depend on @var{out_w}, but they
3226 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
3227 evaluated after @var{out_w} and @var{out_h}.
3229 The @var{x} and @var{y} parameters specify the expressions for the
3230 position of the top-left corner of the output (non-cropped) area. They
3231 are evaluated for each frame. If the evaluated value is not valid, it
3232 is approximated to the nearest valid value.
3234 The expression for @var{x} may depend on @var{y}, and the expression
3235 for @var{y} may depend on @var{x}.
3237 @subsection Examples
3241 Crop area with size 100x100 at position (12,34).
3246 Using named options, the example above becomes:
3248 crop=w=100:h=100:x=12:y=34
3252 Crop the central input area with size 100x100:
3258 Crop the central input area with size 2/3 of the input video:
3260 crop=2/3*in_w:2/3*in_h
3264 Crop the input video central square:
3271 Delimit the rectangle with the top-left corner placed at position
3272 100:100 and the right-bottom corner corresponding to the right-bottom
3273 corner of the input image.
3275 crop=in_w-100:in_h-100:100:100
3279 Crop 10 pixels from the left and right borders, and 20 pixels from
3280 the top and bottom borders
3282 crop=in_w-2*10:in_h-2*20
3286 Keep only the bottom right quarter of the input image:
3288 crop=in_w/2:in_h/2:in_w/2:in_h/2
3292 Crop height for getting Greek harmony:
3294 crop=in_w:1/PHI*in_w
3298 Apply trembling effect:
3300 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)
3304 Apply erratic camera effect depending on timestamp:
3306 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)"
3310 Set x depending on the value of y:
3312 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3318 Auto-detect the crop size.
3320 It calculates the necessary cropping parameters and prints the
3321 recommended parameters via the logging system. The detected dimensions
3322 correspond to the non-black area of the input video.
3324 It accepts the following parameters:
3329 Set higher black value threshold, which can be optionally specified
3330 from nothing (0) to everything (255 for 8bit based formats). An intensity
3331 value greater to the set value is considered non-black. It defaults to 24.
3332 You can also specify a value between 0.0 and 1.0 which will be scaled depending
3333 on the bitdepth of the pixel format.
3336 The value which the width/height should be divisible by. It defaults to
3337 16. The offset is automatically adjusted to center the video. Use 2 to
3338 get only even dimensions (needed for 4:2:2 video). 16 is best when
3339 encoding to most video codecs.
3341 @item reset_count, reset
3342 Set the counter that determines after how many frames cropdetect will
3343 reset the previously detected largest video area and start over to
3344 detect the current optimal crop area. Default value is 0.
3346 This can be useful when channel logos distort the video area. 0
3347 indicates 'never reset', and returns the largest area encountered during
3354 Apply color adjustments using curves.
3356 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3357 component (red, green and blue) has its values defined by @var{N} key points
3358 tied from each other using a smooth curve. The x-axis represents the pixel
3359 values from the input frame, and the y-axis the new pixel values to be set for
3362 By default, a component curve is defined by the two points @var{(0;0)} and
3363 @var{(1;1)}. This creates a straight line where each original pixel value is
3364 "adjusted" to its own value, which means no change to the image.
3366 The filter allows you to redefine these two points and add some more. A new
3367 curve (using a natural cubic spline interpolation) will be define to pass
3368 smoothly through all these new coordinates. The new defined points needs to be
3369 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3370 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3371 the vector spaces, the values will be clipped accordingly.
3373 If there is no key point defined in @code{x=0}, the filter will automatically
3374 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3375 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3377 The filter accepts the following options:
3381 Select one of the available color presets. This option can be used in addition
3382 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3383 options takes priority on the preset values.
3384 Available presets are:
3387 @item color_negative
3390 @item increase_contrast
3392 @item linear_contrast
3393 @item medium_contrast
3395 @item strong_contrast
3398 Default is @code{none}.
3400 Set the master key points. These points will define a second pass mapping. It
3401 is sometimes called a "luminance" or "value" mapping. It can be used with
3402 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3403 post-processing LUT.
3405 Set the key points for the red component.
3407 Set the key points for the green component.
3409 Set the key points for the blue component.
3411 Set the key points for all components (not including master).
3412 Can be used in addition to the other key points component
3413 options. In this case, the unset component(s) will fallback on this
3414 @option{all} setting.
3416 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3419 To avoid some filtergraph syntax conflicts, each key points list need to be
3420 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3422 @subsection Examples
3426 Increase slightly the middle level of blue:
3428 curves=blue='0.5/0.58'
3434 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3436 Here we obtain the following coordinates for each components:
3439 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3441 @code{(0;0) (0.50;0.48) (1;1)}
3443 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3447 The previous example can also be achieved with the associated built-in preset:
3449 curves=preset=vintage
3459 Use a Photoshop preset and redefine the points of the green component:
3461 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3467 Denoise frames using 2D DCT (frequency domain filtering).
3469 This filter is not designed for real time.
3471 The filter accepts the following options:
3475 Set the noise sigma constant.
3477 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3478 coefficient (absolute value) below this threshold with be dropped.
3480 If you need a more advanced filtering, see @option{expr}.
3482 Default is @code{0}.
3485 Set number overlapping pixels for each block. Since the filter can be slow, you
3486 may want to reduce this value, at the cost of a less effective filter and the
3487 risk of various artefacts.
3489 If the overlapping value doesn't permit processing the whole input width or
3490 height, a warning will be displayed and according borders won't be denoised.
3492 Default value is @var{blocksize}-1, which is the best possible setting.
3495 Set the coefficient factor expression.
3497 For each coefficient of a DCT block, this expression will be evaluated as a
3498 multiplier value for the coefficient.
3500 If this is option is set, the @option{sigma} option will be ignored.
3502 The absolute value of the coefficient can be accessed through the @var{c}
3506 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
3507 @var{blocksize}, which is the width and height of the processed blocks.
3509 The default value is @var{3} (8x8) and can be raised to @var{4} for a
3510 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
3511 on the speed processing. Also, a larger block size does not necessarily means a
3515 @subsection Examples
3517 Apply a denoise with a @option{sigma} of @code{4.5}:
3522 The same operation can be achieved using the expression system:
3524 dctdnoiz=e='gte(c, 4.5*3)'
3527 Violent denoise using a block size of @code{16x16}:
3535 Drop duplicated frames at regular intervals.
3537 The filter accepts the following options:
3541 Set the number of frames from which one will be dropped. Setting this to
3542 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3543 Default is @code{5}.
3546 Set the threshold for duplicate detection. If the difference metric for a frame
3547 is less than or equal to this value, then it is declared as duplicate. Default
3551 Set scene change threshold. Default is @code{15}.
3555 Set the size of the x and y-axis blocks used during metric calculations.
3556 Larger blocks give better noise suppression, but also give worse detection of
3557 small movements. Must be a power of two. Default is @code{32}.
3560 Mark main input as a pre-processed input and activate clean source input
3561 stream. This allows the input to be pre-processed with various filters to help
3562 the metrics calculation while keeping the frame selection lossless. When set to
3563 @code{1}, the first stream is for the pre-processed input, and the second
3564 stream is the clean source from where the kept frames are chosen. Default is
3568 Set whether or not chroma is considered in the metric calculations. Default is
3574 Remove judder produced by partially interlaced telecined content.
3576 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3577 source was partially telecined content then the output of @code{pullup,dejudder}
3578 will have a variable frame rate. May change the recorded frame rate of the
3579 container. Aside from that change, this filter will not affect constant frame
3582 The option available in this filter is:
3586 Specify the length of the window over which the judder repeats.
3588 Accepts any integer greater than 1. Useful values are:
3592 If the original was telecined from 24 to 30 fps (Film to NTSC).
3595 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3598 If a mixture of the two.
3601 The default is @samp{4}.
3606 Suppress a TV station logo by a simple interpolation of the surrounding
3607 pixels. Just set a rectangle covering the logo and watch it disappear
3608 (and sometimes something even uglier appear - your mileage may vary).
3610 It accepts the following parameters:
3615 Specify the top left corner coordinates of the logo. They must be
3620 Specify the width and height of the logo to clear. They must be
3624 Specify the thickness of the fuzzy edge of the rectangle (added to
3625 @var{w} and @var{h}). The default value is 4.
3628 When set to 1, a green rectangle is drawn on the screen to simplify
3629 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3630 The default value is 0.
3632 The rectangle is drawn on the outermost pixels which will be (partly)
3633 replaced with interpolated values. The values of the next pixels
3634 immediately outside this rectangle in each direction will be used to
3635 compute the interpolated pixel values inside the rectangle.
3639 @subsection Examples
3643 Set a rectangle covering the area with top left corner coordinates 0,0
3644 and size 100x77, and a band of size 10:
3646 delogo=x=0:y=0:w=100:h=77:band=10
3653 Attempt to fix small changes in horizontal and/or vertical shift. This
3654 filter helps remove camera shake from hand-holding a camera, bumping a
3655 tripod, moving on a vehicle, etc.
3657 The filter accepts the following options:
3665 Specify a rectangular area where to limit the search for motion
3667 If desired the search for motion vectors can be limited to a
3668 rectangular area of the frame defined by its top left corner, width
3669 and height. These parameters have the same meaning as the drawbox
3670 filter which can be used to visualise the position of the bounding
3673 This is useful when simultaneous movement of subjects within the frame
3674 might be confused for camera motion by the motion vector search.
3676 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3677 then the full frame is used. This allows later options to be set
3678 without specifying the bounding box for the motion vector search.
3680 Default - search the whole frame.
3684 Specify the maximum extent of movement in x and y directions in the
3685 range 0-64 pixels. Default 16.
3688 Specify how to generate pixels to fill blanks at the edge of the
3689 frame. Available values are:
3692 Fill zeroes at blank locations
3694 Original image at blank locations
3696 Extruded edge value at blank locations
3698 Mirrored edge at blank locations
3700 Default value is @samp{mirror}.
3703 Specify the blocksize to use for motion search. Range 4-128 pixels,
3707 Specify the contrast threshold for blocks. Only blocks with more than
3708 the specified contrast (difference between darkest and lightest
3709 pixels) will be considered. Range 1-255, default 125.
3712 Specify the search strategy. Available values are:
3715 Set exhaustive search
3717 Set less exhaustive search.
3719 Default value is @samp{exhaustive}.
3722 If set then a detailed log of the motion search is written to the
3726 If set to 1, specify using OpenCL capabilities, only available if
3727 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3733 Apply an exact inverse of the telecine operation. It requires a predefined
3734 pattern specified using the pattern option which must be the same as that passed
3735 to the telecine filter.
3737 This filter accepts the following options:
3746 The default value is @code{top}.
3750 A string of numbers representing the pulldown pattern you wish to apply.
3751 The default value is @code{23}.
3754 A number representing position of the first frame with respect to the telecine
3755 pattern. This is to be used if the stream is cut. The default value is @code{0}.
3760 Draw a colored box on the input image.
3762 It accepts the following parameters:
3767 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3771 The expressions which specify the width and height of the box; if 0 they are interpreted as
3772 the input width and height. It defaults to 0.
3775 Specify the color of the box to write. For the general syntax of this option,
3776 check the "Color" section in the ffmpeg-utils manual. If the special
3777 value @code{invert} is used, the box edge color is the same as the
3778 video with inverted luma.
3781 The expression which sets the thickness of the box edge. Default value is @code{3}.
3783 See below for the list of accepted constants.
3786 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3787 following constants:
3791 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3795 horizontal and vertical chroma subsample values. For example for the
3796 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3800 The input width and height.
3803 The input sample aspect ratio.
3807 The x and y offset coordinates where the box is drawn.
3811 The width and height of the drawn box.
3814 The thickness of the drawn box.
3816 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3817 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3821 @subsection Examples
3825 Draw a black box around the edge of the input image:
3831 Draw a box with color red and an opacity of 50%:
3833 drawbox=10:20:200:60:red@@0.5
3836 The previous example can be specified as:
3838 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3842 Fill the box with pink color:
3844 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3848 Draw a 2-pixel red 2.40:1 mask:
3850 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
3856 Draw a grid on the input image.
3858 It accepts the following parameters:
3863 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3867 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3868 input width and height, respectively, minus @code{thickness}, so image gets
3869 framed. Default to 0.
3872 Specify the color of the grid. For the general syntax of this option,
3873 check the "Color" section in the ffmpeg-utils manual. If the special
3874 value @code{invert} is used, the grid color is the same as the
3875 video with inverted luma.
3878 The expression which sets the thickness of the grid line. Default value is @code{1}.
3880 See below for the list of accepted constants.
3883 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3884 following constants:
3888 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3892 horizontal and vertical chroma subsample values. For example for the
3893 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3897 The input grid cell width and height.
3900 The input sample aspect ratio.
3904 The x and y coordinates of some point of grid intersection (meant to configure offset).
3908 The width and height of the drawn cell.
3911 The thickness of the drawn cell.
3913 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3914 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3918 @subsection Examples
3922 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3924 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3928 Draw a white 3x3 grid with an opacity of 50%:
3930 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3937 Draw a text string or text from a specified file on top of a video, using the
3938 libfreetype library.
3940 To enable compilation of this filter, you need to configure FFmpeg with
3941 @code{--enable-libfreetype}.
3942 To enable default font fallback and the @var{font} option you need to
3943 configure FFmpeg with @code{--enable-libfontconfig}.
3944 To enable the @var{text_shaping} option, you need to configure FFmpeg with
3945 @code{--enable-libfribidi}.
3949 It accepts the following parameters:
3954 Used to draw a box around text using the background color.
3955 The value must be either 1 (enable) or 0 (disable).
3956 The default value of @var{box} is 0.
3959 Set the width of the border to be drawn around the box using @var{boxcolor}.
3960 The default value of @var{boxborderw} is 0.
3963 The color to be used for drawing box around text. For the syntax of this
3964 option, check the "Color" section in the ffmpeg-utils manual.
3966 The default value of @var{boxcolor} is "white".
3969 Set the width of the border to be drawn around the text using @var{bordercolor}.
3970 The default value of @var{borderw} is 0.
3973 Set the color to be used for drawing border around text. For the syntax of this
3974 option, check the "Color" section in the ffmpeg-utils manual.
3976 The default value of @var{bordercolor} is "black".
3979 Select how the @var{text} is expanded. Can be either @code{none},
3980 @code{strftime} (deprecated) or
3981 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3985 If true, check and fix text coords to avoid clipping.
3988 The color to be used for drawing fonts. For the syntax of this option, check
3989 the "Color" section in the ffmpeg-utils manual.
3991 The default value of @var{fontcolor} is "black".
3993 @item fontcolor_expr
3994 String which is expanded the same way as @var{text} to obtain dynamic
3995 @var{fontcolor} value. By default this option has empty value and is not
3996 processed. When this option is set, it overrides @var{fontcolor} option.
3999 The font family to be used for drawing text. By default Sans.
4002 The font file to be used for drawing text. The path must be included.
4003 This parameter is mandatory if the fontconfig support is disabled.
4006 The font size to be used for drawing text.
4007 The default value of @var{fontsize} is 16.
4010 If set to 1, attempt to shape the text (for example, reverse the order of
4011 right-to-left text and join Arabic characters) before drawing it.
4012 Otherwise, just draw the text exactly as given.
4013 By default 1 (if supported).
4016 The flags to be used for loading the fonts.
4018 The flags map the corresponding flags supported by libfreetype, and are
4019 a combination of the following values:
4026 @item vertical_layout
4027 @item force_autohint
4030 @item ignore_global_advance_width
4032 @item ignore_transform
4038 Default value is "default".
4040 For more information consult the documentation for the FT_LOAD_*
4044 The color to be used for drawing a shadow behind the drawn text. For the
4045 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
4047 The default value of @var{shadowcolor} is "black".
4051 The x and y offsets for the text shadow position with respect to the
4052 position of the text. They can be either positive or negative
4053 values. The default value for both is "0".
4056 The starting frame number for the n/frame_num variable. The default value
4060 The size in number of spaces to use for rendering the tab.
4064 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
4065 format. It can be used with or without text parameter. @var{timecode_rate}
4066 option must be specified.
4068 @item timecode_rate, rate, r
4069 Set the timecode frame rate (timecode only).
4072 The text string to be drawn. The text must be a sequence of UTF-8
4074 This parameter is mandatory if no file is specified with the parameter
4078 A text file containing text to be drawn. The text must be a sequence
4079 of UTF-8 encoded characters.
4081 This parameter is mandatory if no text string is specified with the
4082 parameter @var{text}.
4084 If both @var{text} and @var{textfile} are specified, an error is thrown.
4087 If set to 1, the @var{textfile} will be reloaded before each frame.
4088 Be sure to update it atomically, or it may be read partially, or even fail.
4092 The expressions which specify the offsets where text will be drawn
4093 within the video frame. They are relative to the top/left border of the
4096 The default value of @var{x} and @var{y} is "0".
4098 See below for the list of accepted constants and functions.
4101 The parameters for @var{x} and @var{y} are expressions containing the
4102 following constants and functions:
4106 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
4110 horizontal and vertical chroma subsample values. For example for the
4111 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4114 the height of each text line
4122 @item max_glyph_a, ascent
4123 the maximum distance from the baseline to the highest/upper grid
4124 coordinate used to place a glyph outline point, for all the rendered
4126 It is a positive value, due to the grid's orientation with the Y axis
4129 @item max_glyph_d, descent
4130 the maximum distance from the baseline to the lowest grid coordinate
4131 used to place a glyph outline point, for all the rendered glyphs.
4132 This is a negative value, due to the grid's orientation, with the Y axis
4136 maximum glyph height, that is the maximum height for all the glyphs
4137 contained in the rendered text, it is equivalent to @var{ascent} -
4141 maximum glyph width, that is the maximum width for all the glyphs
4142 contained in the rendered text
4145 the number of input frame, starting from 0
4147 @item rand(min, max)
4148 return a random number included between @var{min} and @var{max}
4151 The input sample aspect ratio.
4154 timestamp expressed in seconds, NAN if the input timestamp is unknown
4157 the height of the rendered text
4160 the width of the rendered text
4164 the x and y offset coordinates where the text is drawn.
4166 These parameters allow the @var{x} and @var{y} expressions to refer
4167 each other, so you can for example specify @code{y=x/dar}.
4170 @anchor{drawtext_expansion}
4171 @subsection Text expansion
4173 If @option{expansion} is set to @code{strftime},
4174 the filter recognizes strftime() sequences in the provided text and
4175 expands them accordingly. Check the documentation of strftime(). This
4176 feature is deprecated.
4178 If @option{expansion} is set to @code{none}, the text is printed verbatim.
4180 If @option{expansion} is set to @code{normal} (which is the default),
4181 the following expansion mechanism is used.
4183 The backslash character @samp{\}, followed by any character, always expands to
4184 the second character.
4186 Sequence of the form @code{%@{...@}} are expanded. The text between the
4187 braces is a function name, possibly followed by arguments separated by ':'.
4188 If the arguments contain special characters or delimiters (':' or '@}'),
4189 they should be escaped.
4191 Note that they probably must also be escaped as the value for the
4192 @option{text} option in the filter argument string and as the filter
4193 argument in the filtergraph description, and possibly also for the shell,
4194 that makes up to four levels of escaping; using a text file avoids these
4197 The following functions are available:
4202 The expression evaluation result.
4204 It must take one argument specifying the expression to be evaluated,
4205 which accepts the same constants and functions as the @var{x} and
4206 @var{y} values. Note that not all constants should be used, for
4207 example the text size is not known when evaluating the expression, so
4208 the constants @var{text_w} and @var{text_h} will have an undefined
4211 @item expr_int_format, eif
4212 Evaluate the expression's value and output as formatted integer.
4214 The first argument is the expression to be evaluated, just as for the @var{expr} function.
4215 The second argument specifies the output format. Allowed values are @samp{x},
4216 @samp{X}, @samp{d} and @samp{u}. They are treated exactly as in the
4217 @code{printf} function.
4218 The third parameter is optional and sets the number of positions taken by the output.
4219 It can be used to add padding with zeros from the left.
4222 The time at which the filter is running, expressed in UTC.
4223 It can accept an argument: a strftime() format string.
4226 The time at which the filter is running, expressed in the local time zone.
4227 It can accept an argument: a strftime() format string.
4230 Frame metadata. It must take one argument specifying metadata key.
4233 The frame number, starting from 0.
4236 A 1 character description of the current picture type.
4239 The timestamp of the current frame.
4240 It can take up to two arguments.
4242 The first argument is the format of the timestamp; it defaults to @code{flt}
4243 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
4244 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
4246 The second argument is an offset added to the timestamp.
4250 @subsection Examples
4254 Draw "Test Text" with font FreeSerif, using the default values for the
4255 optional parameters.
4258 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
4262 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
4263 and y=50 (counting from the top-left corner of the screen), text is
4264 yellow with a red box around it. Both the text and the box have an
4268 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
4269 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
4272 Note that the double quotes are not necessary if spaces are not used
4273 within the parameter list.
4276 Show the text at the center of the video frame:
4278 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
4282 Show a text line sliding from right to left in the last row of the video
4283 frame. The file @file{LONG_LINE} is assumed to contain a single line
4286 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
4290 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
4292 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
4296 Draw a single green letter "g", at the center of the input video.
4297 The glyph baseline is placed at half screen height.
4299 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
4303 Show text for 1 second every 3 seconds:
4305 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
4309 Use fontconfig to set the font. Note that the colons need to be escaped.
4311 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
4315 Print the date of a real-time encoding (see strftime(3)):
4317 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
4321 Show text fading in and out (appearing/disappearing):
4324 DS=1.0 # display start
4325 DE=10.0 # display end
4326 FID=1.5 # fade in duration
4327 FOD=5 # fade out duration
4328 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 @}"
4333 For more information about libfreetype, check:
4334 @url{http://www.freetype.org/}.
4336 For more information about fontconfig, check:
4337 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
4339 For more information about libfribidi, check:
4340 @url{http://fribidi.org/}.
4344 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
4346 The filter accepts the following options:
4351 Set low and high threshold values used by the Canny thresholding
4354 The high threshold selects the "strong" edge pixels, which are then
4355 connected through 8-connectivity with the "weak" edge pixels selected
4356 by the low threshold.
4358 @var{low} and @var{high} threshold values must be chosen in the range
4359 [0,1], and @var{low} should be lesser or equal to @var{high}.
4361 Default value for @var{low} is @code{20/255}, and default value for @var{high}
4365 Define the drawing mode.
4369 Draw white/gray wires on black background.
4372 Mix the colors to create a paint/cartoon effect.
4375 Default value is @var{wires}.
4378 @subsection Examples
4382 Standard edge detection with custom values for the hysteresis thresholding:
4384 edgedetect=low=0.1:high=0.4
4388 Painting effect without thresholding:
4390 edgedetect=mode=colormix:high=0
4395 Set brightness, contrast, saturation and approximate gamma adjustment.
4397 The filter accepts the following options:
4401 Set the contrast expression. The value must be a float value in range
4402 @code{-2.0} to @code{2.0}. The default value is "0".
4405 Set the brightness expression. The value must be a float value in
4406 range @code{-1.0} to @code{1.0}. The default value is "0".
4409 Set the saturation expression. The value must be a float in
4410 range @code{0.0} to @code{3.0}. The default value is "1".
4413 Set the gamma expression. The value must be a float in range
4414 @code{0.1} to @code{10.0}. The default value is "1".
4417 Set the gamma expression for red. The value must be a float in
4418 range @code{0.1} to @code{10.0}. The default value is "1".
4421 Set the gamma expression for green. The value must be a float in range
4422 @code{0.1} to @code{10.0}. The default value is "1".
4425 Set the gamma expression for blue. The value must be a float in range
4426 @code{0.1} to @code{10.0}. The default value is "1".
4429 Set the gamma weight expression. It can be used to reduce the effect
4430 of a high gamma value on bright image areas, e.g. keep them from
4431 getting overamplified and just plain white. The value must be a float
4432 in range @code{0.0} to @code{1.0}. A value of @code{0.0} turns the
4433 gamma correction all the way down while @code{1.0} leaves it at its
4434 full strength. Default is "1".
4437 Set when the expressions for brightness, contrast, saturation and
4438 gamma expressions are evaluated.
4440 It accepts the following values:
4443 only evaluate expressions once during the filter initialization or
4444 when a command is processed
4447 evaluate expressions for each incoming frame
4450 Default value is @samp{init}.
4453 The expressions accept the following parameters:
4456 frame count of the input frame starting from 0
4459 byte position of the corresponding packet in the input file, NAN if
4463 frame rate of the input video, NAN if the input frame rate is unknown
4466 timestamp expressed in seconds, NAN if the input timestamp is unknown
4469 @subsection Commands
4470 The filter supports the following commands:
4474 Set the contrast expression.
4477 Set the brightness expression.
4480 Set the saturation expression.
4483 Set the gamma expression.
4486 Set the gamma_r expression.
4489 Set gamma_g expression.
4492 Set gamma_b expression.
4495 Set gamma_weight expression.
4497 The command accepts the same syntax of the corresponding option.
4499 If the specified expression is not valid, it is kept at its current
4504 @section extractplanes
4506 Extract color channel components from input video stream into
4507 separate grayscale video streams.
4509 The filter accepts the following option:
4513 Set plane(s) to extract.
4515 Available values for planes are:
4526 Choosing planes not available in the input will result in an error.
4527 That means you cannot select @code{r}, @code{g}, @code{b} planes
4528 with @code{y}, @code{u}, @code{v} planes at same time.
4531 @subsection Examples
4535 Extract luma, u and v color channel component from input video frame
4536 into 3 grayscale outputs:
4538 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
4544 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4546 For each input image, the filter will compute the optimal mapping from
4547 the input to the output given the codebook length, that is the number
4548 of distinct output colors.
4550 This filter accepts the following options.
4553 @item codebook_length, l
4554 Set codebook length. The value must be a positive integer, and
4555 represents the number of distinct output colors. Default value is 256.
4558 Set the maximum number of iterations to apply for computing the optimal
4559 mapping. The higher the value the better the result and the higher the
4560 computation time. Default value is 1.
4563 Set a random seed, must be an integer included between 0 and
4564 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4565 will try to use a good random seed on a best effort basis.
4570 Apply a fade-in/out effect to the input video.
4572 It accepts the following parameters:
4576 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4578 Default is @code{in}.
4580 @item start_frame, s
4581 Specify the number of the frame to start applying the fade
4582 effect at. Default is 0.
4585 The number of frames that the fade effect lasts. At the end of the
4586 fade-in effect, the output video will have the same intensity as the input video.
4587 At the end of the fade-out transition, the output video will be filled with the
4588 selected @option{color}.
4592 If set to 1, fade only alpha channel, if one exists on the input.
4595 @item start_time, st
4596 Specify the timestamp (in seconds) of the frame to start to apply the fade
4597 effect. If both start_frame and start_time are specified, the fade will start at
4598 whichever comes last. Default is 0.
4601 The number of seconds for which the fade effect has to last. At the end of the
4602 fade-in effect the output video will have the same intensity as the input video,
4603 at the end of the fade-out transition the output video will be filled with the
4604 selected @option{color}.
4605 If both duration and nb_frames are specified, duration is used. Default is 0
4606 (nb_frames is used by default).
4609 Specify the color of the fade. Default is "black".
4612 @subsection Examples
4616 Fade in the first 30 frames of video:
4621 The command above is equivalent to:
4627 Fade out the last 45 frames of a 200-frame video:
4630 fade=type=out:start_frame=155:nb_frames=45
4634 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4636 fade=in:0:25, fade=out:975:25
4640 Make the first 5 frames yellow, then fade in from frame 5-24:
4642 fade=in:5:20:color=yellow
4646 Fade in alpha over first 25 frames of video:
4648 fade=in:0:25:alpha=1
4652 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4654 fade=t=in:st=5.5:d=0.5
4660 Apply arbitrary expressions to samples in frequency domain
4664 Adjust the dc value (gain) of the luma plane of the image. The filter
4665 accepts an integer value in range @code{0} to @code{1000}. The default
4666 value is set to @code{0}.
4669 Adjust the dc value (gain) of the 1st chroma plane of the image. The
4670 filter accepts an integer value in range @code{0} to @code{1000}. The
4671 default value is set to @code{0}.
4674 Adjust the dc value (gain) of the 2nd chroma plane of the image. The
4675 filter accepts an integer value in range @code{0} to @code{1000}. The
4676 default value is set to @code{0}.
4679 Set the frequency domain weight expression for the luma plane.
4682 Set the frequency domain weight expression for the 1st chroma plane.
4685 Set the frequency domain weight expression for the 2nd chroma plane.
4687 The filter accepts the following variables:
4690 The coordinates of the current sample.
4694 The width and height of the image.
4697 @subsection Examples
4703 fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
4709 fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
4715 fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
4722 Extract a single field from an interlaced image using stride
4723 arithmetic to avoid wasting CPU time. The output frames are marked as
4726 The filter accepts the following options:
4730 Specify whether to extract the top (if the value is @code{0} or
4731 @code{top}) or the bottom field (if the value is @code{1} or
4737 Field matching filter for inverse telecine. It is meant to reconstruct the
4738 progressive frames from a telecined stream. The filter does not drop duplicated
4739 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4740 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4742 The separation of the field matching and the decimation is notably motivated by
4743 the possibility of inserting a de-interlacing filter fallback between the two.
4744 If the source has mixed telecined and real interlaced content,
4745 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4746 But these remaining combed frames will be marked as interlaced, and thus can be
4747 de-interlaced by a later filter such as @ref{yadif} before decimation.
4749 In addition to the various configuration options, @code{fieldmatch} can take an
4750 optional second stream, activated through the @option{ppsrc} option. If
4751 enabled, the frames reconstruction will be based on the fields and frames from
4752 this second stream. This allows the first input to be pre-processed in order to
4753 help the various algorithms of the filter, while keeping the output lossless
4754 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4755 or brightness/contrast adjustments can help.
4757 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4758 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4759 which @code{fieldmatch} is based on. While the semantic and usage are very
4760 close, some behaviour and options names can differ.
4762 The @ref{decimate} filter currently only works for constant frame rate input.
4763 Do not use @code{fieldmatch} and @ref{decimate} if your input has mixed
4764 telecined and progressive content with changing framerate.
4766 The filter accepts the following options:
4770 Specify the assumed field order of the input stream. Available values are:
4774 Auto detect parity (use FFmpeg's internal parity value).
4776 Assume bottom field first.
4778 Assume top field first.
4781 Note that it is sometimes recommended not to trust the parity announced by the
4784 Default value is @var{auto}.
4787 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4788 sense that it won't risk creating jerkiness due to duplicate frames when
4789 possible, but if there are bad edits or blended fields it will end up
4790 outputting combed frames when a good match might actually exist. On the other
4791 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4792 but will almost always find a good frame if there is one. The other values are
4793 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4794 jerkiness and creating duplicate frames versus finding good matches in sections
4795 with bad edits, orphaned fields, blended fields, etc.
4797 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4799 Available values are:
4803 2-way matching (p/c)
4805 2-way matching, and trying 3rd match if still combed (p/c + n)
4807 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4809 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4810 still combed (p/c + n + u/b)
4812 3-way matching (p/c/n)
4814 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4815 detected as combed (p/c/n + u/b)
4818 The parenthesis at the end indicate the matches that would be used for that
4819 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4822 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4825 Default value is @var{pc_n}.
4828 Mark the main input stream as a pre-processed input, and enable the secondary
4829 input stream as the clean source to pick the fields from. See the filter
4830 introduction for more details. It is similar to the @option{clip2} feature from
4833 Default value is @code{0} (disabled).
4836 Set the field to match from. It is recommended to set this to the same value as
4837 @option{order} unless you experience matching failures with that setting. In
4838 certain circumstances changing the field that is used to match from can have a
4839 large impact on matching performance. Available values are:
4843 Automatic (same value as @option{order}).
4845 Match from the bottom field.
4847 Match from the top field.
4850 Default value is @var{auto}.
4853 Set whether or not chroma is included during the match comparisons. In most
4854 cases it is recommended to leave this enabled. You should set this to @code{0}
4855 only if your clip has bad chroma problems such as heavy rainbowing or other
4856 artifacts. Setting this to @code{0} could also be used to speed things up at
4857 the cost of some accuracy.
4859 Default value is @code{1}.
4863 These define an exclusion band which excludes the lines between @option{y0} and
4864 @option{y1} from being included in the field matching decision. An exclusion
4865 band can be used to ignore subtitles, a logo, or other things that may
4866 interfere with the matching. @option{y0} sets the starting scan line and
4867 @option{y1} sets the ending line; all lines in between @option{y0} and
4868 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4869 @option{y0} and @option{y1} to the same value will disable the feature.
4870 @option{y0} and @option{y1} defaults to @code{0}.
4873 Set the scene change detection threshold as a percentage of maximum change on
4874 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4875 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4876 @option{scthresh} is @code{[0.0, 100.0]}.
4878 Default value is @code{12.0}.
4881 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4882 account the combed scores of matches when deciding what match to use as the
4883 final match. Available values are:
4887 No final matching based on combed scores.
4889 Combed scores are only used when a scene change is detected.
4891 Use combed scores all the time.
4894 Default is @var{sc}.
4897 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4898 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4899 Available values are:
4903 No forced calculation.
4905 Force p/c/n calculations.
4907 Force p/c/n/u/b calculations.
4910 Default value is @var{none}.
4913 This is the area combing threshold used for combed frame detection. This
4914 essentially controls how "strong" or "visible" combing must be to be detected.
4915 Larger values mean combing must be more visible and smaller values mean combing
4916 can be less visible or strong and still be detected. Valid settings are from
4917 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4918 be detected as combed). This is basically a pixel difference value. A good
4919 range is @code{[8, 12]}.
4921 Default value is @code{9}.
4924 Sets whether or not chroma is considered in the combed frame decision. Only
4925 disable this if your source has chroma problems (rainbowing, etc.) that are
4926 causing problems for the combed frame detection with chroma enabled. Actually,
4927 using @option{chroma}=@var{0} is usually more reliable, except for the case
4928 where there is chroma only combing in the source.
4930 Default value is @code{0}.
4934 Respectively set the x-axis and y-axis size of the window used during combed
4935 frame detection. This has to do with the size of the area in which
4936 @option{combpel} pixels are required to be detected as combed for a frame to be
4937 declared combed. See the @option{combpel} parameter description for more info.
4938 Possible values are any number that is a power of 2 starting at 4 and going up
4941 Default value is @code{16}.
4944 The number of combed pixels inside any of the @option{blocky} by
4945 @option{blockx} size blocks on the frame for the frame to be detected as
4946 combed. While @option{cthresh} controls how "visible" the combing must be, this
4947 setting controls "how much" combing there must be in any localized area (a
4948 window defined by the @option{blockx} and @option{blocky} settings) on the
4949 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4950 which point no frames will ever be detected as combed). This setting is known
4951 as @option{MI} in TFM/VFM vocabulary.
4953 Default value is @code{80}.
4956 @anchor{p/c/n/u/b meaning}
4957 @subsection p/c/n/u/b meaning
4959 @subsubsection p/c/n
4961 We assume the following telecined stream:
4964 Top fields: 1 2 2 3 4
4965 Bottom fields: 1 2 3 4 4
4968 The numbers correspond to the progressive frame the fields relate to. Here, the
4969 first two frames are progressive, the 3rd and 4th are combed, and so on.
4971 When @code{fieldmatch} is configured to run a matching from bottom
4972 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4977 B 1 2 3 4 4 <-- matching reference
4986 As a result of the field matching, we can see that some frames get duplicated.
4987 To perform a complete inverse telecine, you need to rely on a decimation filter
4988 after this operation. See for instance the @ref{decimate} filter.
4990 The same operation now matching from top fields (@option{field}=@var{top})
4995 T 1 2 2 3 4 <-- matching reference
5005 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
5006 basically, they refer to the frame and field of the opposite parity:
5009 @item @var{p} matches the field of the opposite parity in the previous frame
5010 @item @var{c} matches the field of the opposite parity in the current frame
5011 @item @var{n} matches the field of the opposite parity in the next frame
5016 The @var{u} and @var{b} matching are a bit special in the sense that they match
5017 from the opposite parity flag. In the following examples, we assume that we are
5018 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
5019 'x' is placed above and below each matched fields.
5021 With bottom matching (@option{field}=@var{bottom}):
5026 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
5027 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
5035 With top matching (@option{field}=@var{top}):
5040 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
5041 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
5049 @subsection Examples
5051 Simple IVTC of a top field first telecined stream:
5053 fieldmatch=order=tff:combmatch=none, decimate
5056 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
5058 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
5063 Transform the field order of the input video.
5065 It accepts the following parameters:
5070 The output field order. Valid values are @var{tff} for top field first or @var{bff}
5071 for bottom field first.
5074 The default value is @samp{tff}.
5076 The transformation is done by shifting the picture content up or down
5077 by one line, and filling the remaining line with appropriate picture content.
5078 This method is consistent with most broadcast field order converters.
5080 If the input video is not flagged as being interlaced, or it is already
5081 flagged as being of the required output field order, then this filter does
5082 not alter the incoming video.
5084 It is very useful when converting to or from PAL DV material,
5085 which is bottom field first.
5089 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
5094 Buffer input images and send them when they are requested.
5096 It is mainly useful when auto-inserted by the libavfilter
5099 It does not take parameters.
5104 Convert the input video to one of the specified pixel formats.
5105 Libavfilter will try to pick one that is suitable as input to
5108 It accepts the following parameters:
5112 A '|'-separated list of pixel format names, such as
5113 "pix_fmts=yuv420p|monow|rgb24".
5117 @subsection Examples
5121 Convert the input video to the @var{yuv420p} format
5123 format=pix_fmts=yuv420p
5126 Convert the input video to any of the formats in the list
5128 format=pix_fmts=yuv420p|yuv444p|yuv410p
5135 Convert the video to specified constant frame rate by duplicating or dropping
5136 frames as necessary.
5138 It accepts the following parameters:
5142 The desired output frame rate. The default is @code{25}.
5147 Possible values are:
5150 zero round towards 0
5154 round towards -infinity
5156 round towards +infinity
5160 The default is @code{near}.
5163 Assume the first PTS should be the given value, in seconds. This allows for
5164 padding/trimming at the start of stream. By default, no assumption is made
5165 about the first frame's expected PTS, so no padding or trimming is done.
5166 For example, this could be set to 0 to pad the beginning with duplicates of
5167 the first frame if a video stream starts after the audio stream or to trim any
5168 frames with a negative PTS.
5172 Alternatively, the options can be specified as a flat string:
5173 @var{fps}[:@var{round}].
5175 See also the @ref{setpts} filter.
5177 @subsection Examples
5181 A typical usage in order to set the fps to 25:
5187 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
5189 fps=fps=film:round=near
5195 Pack two different video streams into a stereoscopic video, setting proper
5196 metadata on supported codecs. The two views should have the same size and
5197 framerate and processing will stop when the shorter video ends. Please note
5198 that you may conveniently adjust view properties with the @ref{scale} and
5201 It accepts the following parameters:
5205 The desired packing format. Supported values are:
5210 The views are next to each other (default).
5213 The views are on top of each other.
5216 The views are packed by line.
5219 The views are packed by column.
5222 The views are temporally interleaved.
5231 # Convert left and right views into a frame-sequential video
5232 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
5234 # Convert views into a side-by-side video with the same output resolution as the input
5235 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
5240 Select one frame every N-th frame.
5242 This filter accepts the following option:
5245 Select frame after every @code{step} frames.
5246 Allowed values are positive integers higher than 0. Default value is @code{1}.
5252 Apply a frei0r effect to the input video.
5254 To enable the compilation of this filter, you need to install the frei0r
5255 header and configure FFmpeg with @code{--enable-frei0r}.
5257 It accepts the following parameters:
5262 The name of the frei0r effect to load. If the environment variable
5263 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
5264 directories specified by the colon-separated list in @env{FREIOR_PATH}.
5265 Otherwise, the standard frei0r paths are searched, in this order:
5266 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
5267 @file{/usr/lib/frei0r-1/}.
5270 A '|'-separated list of parameters to pass to the frei0r effect.
5274 A frei0r effect parameter can be a boolean (its value is either
5275 "y" or "n"), a double, a color (specified as
5276 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
5277 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
5278 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
5279 @var{X} and @var{Y} are floating point numbers) and/or a string.
5281 The number and types of parameters depend on the loaded effect. If an
5282 effect parameter is not specified, the default value is set.
5284 @subsection Examples
5288 Apply the distort0r effect, setting the first two double parameters:
5290 frei0r=filter_name=distort0r:filter_params=0.5|0.01
5294 Apply the colordistance effect, taking a color as the first parameter:
5296 frei0r=colordistance:0.2/0.3/0.4
5297 frei0r=colordistance:violet
5298 frei0r=colordistance:0x112233
5302 Apply the perspective effect, specifying the top left and top right image
5305 frei0r=perspective:0.2/0.2|0.8/0.2
5309 For more information, see
5310 @url{http://frei0r.dyne.org}
5314 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
5316 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
5317 processing filter, one of them is performed once per block, not per pixel.
5318 This allows for much higher speed.
5320 The filter accepts the following options:
5324 Set quality. This option defines the number of levels for averaging. It accepts
5325 an integer in the range 4-5. Default value is @code{4}.
5328 Force a constant quantization parameter. It accepts an integer in range 0-63.
5329 If not set, the filter will use the QP from the video stream (if available).
5332 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
5333 more details but also more artifacts, while higher values make the image smoother
5334 but also blurrier. Default value is @code{0} − PSNR optimal.
5337 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
5338 option may cause flicker since the B-Frames have often larger QP. Default is
5339 @code{0} (not enabled).
5345 The filter accepts the following options:
5349 Set the luminance expression.
5351 Set the chrominance blue expression.
5353 Set the chrominance red expression.
5355 Set the alpha expression.
5357 Set the red expression.
5359 Set the green expression.
5361 Set the blue expression.
5364 The colorspace is selected according to the specified options. If one
5365 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
5366 options is specified, the filter will automatically select a YCbCr
5367 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
5368 @option{blue_expr} options is specified, it will select an RGB
5371 If one of the chrominance expression is not defined, it falls back on the other
5372 one. If no alpha expression is specified it will evaluate to opaque value.
5373 If none of chrominance expressions are specified, they will evaluate
5374 to the luminance expression.
5376 The expressions can use the following variables and functions:
5380 The sequential number of the filtered frame, starting from @code{0}.
5384 The coordinates of the current sample.
5388 The width and height of the image.
5392 Width and height scale depending on the currently filtered plane. It is the
5393 ratio between the corresponding luma plane number of pixels and the current
5394 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
5395 @code{0.5,0.5} for chroma planes.
5398 Time of the current frame, expressed in seconds.
5401 Return the value of the pixel at location (@var{x},@var{y}) of the current
5405 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
5409 Return the value of the pixel at location (@var{x},@var{y}) of the
5410 blue-difference chroma plane. Return 0 if there is no such plane.
5413 Return the value of the pixel at location (@var{x},@var{y}) of the
5414 red-difference chroma plane. Return 0 if there is no such plane.
5419 Return the value of the pixel at location (@var{x},@var{y}) of the
5420 red/green/blue component. Return 0 if there is no such component.
5423 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
5424 plane. Return 0 if there is no such plane.
5427 For functions, if @var{x} and @var{y} are outside the area, the value will be
5428 automatically clipped to the closer edge.
5430 @subsection Examples
5434 Flip the image horizontally:
5440 Generate a bidimensional sine wave, with angle @code{PI/3} and a
5441 wavelength of 100 pixels:
5443 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
5447 Generate a fancy enigmatic moving light:
5449 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
5453 Generate a quick emboss effect:
5455 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
5459 Modify RGB components depending on pixel position:
5461 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
5465 Create a radial gradient that is the same size as the input (also see
5466 the @ref{vignette} filter):
5468 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
5472 Create a linear gradient to use as a mask for another filter, then
5473 compose with @ref{overlay}. In this example the video will gradually
5474 become more blurry from the top to the bottom of the y-axis as defined
5475 by the linear gradient:
5477 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
5483 Fix the banding artifacts that are sometimes introduced into nearly flat
5484 regions by truncation to 8bit color depth.
5485 Interpolate the gradients that should go where the bands are, and
5488 It is designed for playback only. Do not use it prior to
5489 lossy compression, because compression tends to lose the dither and
5490 bring back the bands.
5492 It accepts the following parameters:
5497 The maximum amount by which the filter will change any one pixel. This is also
5498 the threshold for detecting nearly flat regions. Acceptable values range from
5499 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
5503 The neighborhood to fit the gradient to. A larger radius makes for smoother
5504 gradients, but also prevents the filter from modifying the pixels near detailed
5505 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
5506 values will be clipped to the valid range.
5510 Alternatively, the options can be specified as a flat string:
5511 @var{strength}[:@var{radius}]
5513 @subsection Examples
5517 Apply the filter with a @code{3.5} strength and radius of @code{8}:
5523 Specify radius, omitting the strength (which will fall-back to the default
5534 Apply a Hald CLUT to a video stream.
5536 First input is the video stream to process, and second one is the Hald CLUT.
5537 The Hald CLUT input can be a simple picture or a complete video stream.
5539 The filter accepts the following options:
5543 Force termination when the shortest input terminates. Default is @code{0}.
5545 Continue applying the last CLUT after the end of the stream. A value of
5546 @code{0} disable the filter after the last frame of the CLUT is reached.
5547 Default is @code{1}.
5550 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
5551 filters share the same internals).
5553 More information about the Hald CLUT can be found on Eskil Steenberg's website
5554 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
5556 @subsection Workflow examples
5558 @subsubsection Hald CLUT video stream
5560 Generate an identity Hald CLUT stream altered with various effects:
5562 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
5565 Note: make sure you use a lossless codec.
5567 Then use it with @code{haldclut} to apply it on some random stream:
5569 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
5572 The Hald CLUT will be applied to the 10 first seconds (duration of
5573 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
5574 to the remaining frames of the @code{mandelbrot} stream.
5576 @subsubsection Hald CLUT with preview
5578 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
5579 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
5580 biggest possible square starting at the top left of the picture. The remaining
5581 padding pixels (bottom or right) will be ignored. This area can be used to add
5582 a preview of the Hald CLUT.
5584 Typically, the following generated Hald CLUT will be supported by the
5585 @code{haldclut} filter:
5588 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
5589 pad=iw+320 [padded_clut];
5590 smptebars=s=320x256, split [a][b];
5591 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
5592 [main][b] overlay=W-320" -frames:v 1 clut.png
5595 It contains the original and a preview of the effect of the CLUT: SMPTE color
5596 bars are displayed on the right-top, and below the same color bars processed by
5599 Then, the effect of this Hald CLUT can be visualized with:
5601 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
5606 Flip the input video horizontally.
5608 For example, to horizontally flip the input video with @command{ffmpeg}:
5610 ffmpeg -i in.avi -vf "hflip" out.avi
5614 This filter applies a global color histogram equalization on a
5617 It can be used to correct video that has a compressed range of pixel
5618 intensities. The filter redistributes the pixel intensities to
5619 equalize their distribution across the intensity range. It may be
5620 viewed as an "automatically adjusting contrast filter". This filter is
5621 useful only for correcting degraded or poorly captured source
5624 The filter accepts the following options:
5628 Determine the amount of equalization to be applied. As the strength
5629 is reduced, the distribution of pixel intensities more-and-more
5630 approaches that of the input frame. The value must be a float number
5631 in the range [0,1] and defaults to 0.200.
5634 Set the maximum intensity that can generated and scale the output
5635 values appropriately. The strength should be set as desired and then
5636 the intensity can be limited if needed to avoid washing-out. The value
5637 must be a float number in the range [0,1] and defaults to 0.210.
5640 Set the antibanding level. If enabled the filter will randomly vary
5641 the luminance of output pixels by a small amount to avoid banding of
5642 the histogram. Possible values are @code{none}, @code{weak} or
5643 @code{strong}. It defaults to @code{none}.
5648 Compute and draw a color distribution histogram for the input video.
5650 The computed histogram is a representation of the color component
5651 distribution in an image.
5653 The filter accepts the following options:
5659 It accepts the following values:
5662 Standard histogram that displays the color components distribution in an
5663 image. Displays color graph for each color component. Shows distribution of
5664 the Y, U, V, A or R, G, B components, depending on input format, in the
5665 current frame. Below each graph a color component scale meter is shown.
5668 Displays chroma values (U/V color placement) in a two dimensional
5669 graph (which is called a vectorscope). The brighter a pixel in the
5670 vectorscope, the more pixels of the input frame correspond to that pixel
5671 (i.e., more pixels have this chroma value). The V component is displayed on
5672 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5673 side being V = 255. The U component is displayed on the vertical (Y) axis,
5674 with the top representing U = 0 and the bottom representing U = 255.
5676 The position of a white pixel in the graph corresponds to the chroma value of
5677 a pixel of the input clip. The graph can therefore be used to read the hue
5678 (color flavor) and the saturation (the dominance of the hue in the color). As
5679 the hue of a color changes, it moves around the square. At the center of the
5680 square the saturation is zero, which means that the corresponding pixel has no
5681 color. If the amount of a specific color is increased (while leaving the other
5682 colors unchanged) the saturation increases, and the indicator moves towards
5683 the edge of the square.
5686 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5690 Per row/column color component graph. In row mode, the graph on the left side
5691 represents color component value 0 and the right side represents value = 255.
5692 In column mode, the top side represents color component value = 0 and bottom
5693 side represents value = 255.
5695 Default value is @code{levels}.
5698 Set height of level in @code{levels}. Default value is @code{200}.
5699 Allowed range is [50, 2048].
5702 Set height of color scale in @code{levels}. Default value is @code{12}.
5703 Allowed range is [0, 40].
5706 Set step for @code{waveform} mode. Smaller values are useful to find out how
5707 many values of the same luminance are distributed across input rows/columns.
5708 Default value is @code{10}. Allowed range is [1, 255].
5711 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5712 Default is @code{row}.
5714 @item waveform_mirror
5715 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5716 means mirrored. In mirrored mode, higher values will be represented on the left
5717 side for @code{row} mode and at the top for @code{column} mode. Default is
5718 @code{0} (unmirrored).
5721 Set display mode for @code{waveform} and @code{levels}.
5722 It accepts the following values:
5725 Display separate graph for the color components side by side in
5726 @code{row} waveform mode or one below the other in @code{column} waveform mode
5727 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5728 per color component graphs are placed below each other.
5730 Using this display mode in @code{waveform} histogram mode makes it easy to
5731 spot color casts in the highlights and shadows of an image, by comparing the
5732 contours of the top and the bottom graphs of each waveform. Since whites,
5733 grays, and blacks are characterized by exactly equal amounts of red, green,
5734 and blue, neutral areas of the picture should display three waveforms of
5735 roughly equal width/height. If not, the correction is easy to perform by
5736 making level adjustments the three waveforms.
5739 Presents information identical to that in the @code{parade}, except
5740 that the graphs representing color components are superimposed directly
5743 This display mode in @code{waveform} histogram mode makes it easier to spot
5744 relative differences or similarities in overlapping areas of the color
5745 components that are supposed to be identical, such as neutral whites, grays,
5748 Default is @code{parade}.
5751 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5752 Default is @code{linear}.
5755 @subsection Examples
5760 Calculate and draw histogram:
5762 ffplay -i input -vf histogram
5770 This is a high precision/quality 3d denoise filter. It aims to reduce
5771 image noise, producing smooth images and making still images really
5772 still. It should enhance compressibility.
5774 It accepts the following optional parameters:
5778 A non-negative floating point number which specifies spatial luma strength.
5781 @item chroma_spatial
5782 A non-negative floating point number which specifies spatial chroma strength.
5783 It defaults to 3.0*@var{luma_spatial}/4.0.
5786 A floating point number which specifies luma temporal strength. It defaults to
5787 6.0*@var{luma_spatial}/4.0.
5790 A floating point number which specifies chroma temporal strength. It defaults to
5791 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5796 Apply a high-quality magnification filter designed for pixel art. This filter
5797 was originally created by Maxim Stepin.
5799 It accepts the following option:
5803 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
5804 @code{hq3x} and @code{4} for @code{hq4x}.
5805 Default is @code{3}.
5810 Modify the hue and/or the saturation of the input.
5812 It accepts the following parameters:
5816 Specify the hue angle as a number of degrees. It accepts an expression,
5817 and defaults to "0".
5820 Specify the saturation in the [-10,10] range. It accepts an expression and
5824 Specify the hue angle as a number of radians. It accepts an
5825 expression, and defaults to "0".
5828 Specify the brightness in the [-10,10] range. It accepts an expression and
5832 @option{h} and @option{H} are mutually exclusive, and can't be
5833 specified at the same time.
5835 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5836 expressions containing the following constants:
5840 frame count of the input frame starting from 0
5843 presentation timestamp of the input frame expressed in time base units
5846 frame rate of the input video, NAN if the input frame rate is unknown
5849 timestamp expressed in seconds, NAN if the input timestamp is unknown
5852 time base of the input video
5855 @subsection Examples
5859 Set the hue to 90 degrees and the saturation to 1.0:
5865 Same command but expressing the hue in radians:
5871 Rotate hue and make the saturation swing between 0
5872 and 2 over a period of 1 second:
5874 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5878 Apply a 3 seconds saturation fade-in effect starting at 0:
5883 The general fade-in expression can be written as:
5885 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5889 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5891 hue="s=max(0\, min(1\, (8-t)/3))"
5894 The general fade-out expression can be written as:
5896 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5901 @subsection Commands
5903 This filter supports the following commands:
5909 Modify the hue and/or the saturation and/or brightness of the input video.
5910 The command accepts the same syntax of the corresponding option.
5912 If the specified expression is not valid, it is kept at its current
5918 Detect video interlacing type.
5920 This filter tries to detect if the input frames as interlaced, progressive,
5921 top or bottom field first. It will also try and detect fields that are
5922 repeated between adjacent frames (a sign of telecine).
5924 Single frame detection considers only immediately adjacent frames when classifying each frame.
5925 Multiple frame detection incorporates the classification history of previous frames.
5927 The filter will log these metadata values:
5930 @item single.current_frame
5931 Detected type of current frame using single-frame detection. One of:
5932 ``tff'' (top field first), ``bff'' (bottom field first),
5933 ``progressive'', or ``undetermined''
5936 Cumulative number of frames detected as top field first using single-frame detection.
5939 Cumulative number of frames detected as top field first using multiple-frame detection.
5942 Cumulative number of frames detected as bottom field first using single-frame detection.
5944 @item multiple.current_frame
5945 Detected type of current frame using multiple-frame detection. One of:
5946 ``tff'' (top field first), ``bff'' (bottom field first),
5947 ``progressive'', or ``undetermined''
5950 Cumulative number of frames detected as bottom field first using multiple-frame detection.
5952 @item single.progressive
5953 Cumulative number of frames detected as progressive using single-frame detection.
5955 @item multiple.progressive
5956 Cumulative number of frames detected as progressive using multiple-frame detection.
5958 @item single.undetermined
5959 Cumulative number of frames that could not be classified using single-frame detection.
5961 @item multiple.undetermined
5962 Cumulative number of frames that could not be classified using multiple-frame detection.
5964 @item repeated.current_frame
5965 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
5967 @item repeated.neither
5968 Cumulative number of frames with no repeated field.
5971 Cumulative number of frames with the top field repeated from the previous frame's top field.
5973 @item repeated.bottom
5974 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
5977 The filter accepts the following options:
5981 Set interlacing threshold.
5983 Set progressive threshold.
5985 Threshold for repeated field detection.
5987 Number of frames after which a given frame's contribution to the
5988 statistics is halved (i.e., it contributes only 0.5 to it's
5989 classification). The default of 0 means that all frames seen are given
5990 full weight of 1.0 forever.
5991 @item analyze_interlaced_flag
5992 When this is not 0 then idet will use the specified number of frames to determine
5993 if the interlaced flag is accurate, it will not count undetermined frames.
5994 If the flag is found to be accurate it will be used without any further
5995 computations, if it is found to be inaccuarte it will be cleared without any
5996 further computations. This allows inserting the idet filter as a low computational
5997 method to clean up the interlaced flag
6002 Deinterleave or interleave fields.
6004 This filter allows one to process interlaced images fields without
6005 deinterlacing them. Deinterleaving splits the input frame into 2
6006 fields (so called half pictures). Odd lines are moved to the top
6007 half of the output image, even lines to the bottom half.
6008 You can process (filter) them independently and then re-interleave them.
6010 The filter accepts the following options:
6014 @item chroma_mode, c
6016 Available values for @var{luma_mode}, @var{chroma_mode} and
6017 @var{alpha_mode} are:
6023 @item deinterleave, d
6024 Deinterleave fields, placing one above the other.
6027 Interleave fields. Reverse the effect of deinterleaving.
6029 Default value is @code{none}.
6032 @item chroma_swap, cs
6033 @item alpha_swap, as
6034 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
6039 Simple interlacing filter from progressive contents. This interleaves upper (or
6040 lower) lines from odd frames with lower (or upper) lines from even frames,
6041 halving the frame rate and preserving image height.
6044 Original Original New Frame
6045 Frame 'j' Frame 'j+1' (tff)
6046 ========== =========== ==================
6047 Line 0 --------------------> Frame 'j' Line 0
6048 Line 1 Line 1 ----> Frame 'j+1' Line 1
6049 Line 2 ---------------------> Frame 'j' Line 2
6050 Line 3 Line 3 ----> Frame 'j+1' Line 3
6052 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
6055 It accepts the following optional parameters:
6059 This determines whether the interlaced frame is taken from the even
6060 (tff - default) or odd (bff) lines of the progressive frame.
6063 Enable (default) or disable the vertical lowpass filter to avoid twitter
6064 interlacing and reduce moire patterns.
6069 Deinterlace input video by applying Donald Graft's adaptive kernel
6070 deinterling. Work on interlaced parts of a video to produce
6073 The description of the accepted parameters follows.
6077 Set the threshold which affects the filter's tolerance when
6078 determining if a pixel line must be processed. It must be an integer
6079 in the range [0,255] and defaults to 10. A value of 0 will result in
6080 applying the process on every pixels.
6083 Paint pixels exceeding the threshold value to white if set to 1.
6087 Set the fields order. Swap fields if set to 1, leave fields alone if
6091 Enable additional sharpening if set to 1. Default is 0.
6094 Enable twoway sharpening if set to 1. Default is 0.
6097 @subsection Examples
6101 Apply default values:
6103 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
6107 Enable additional sharpening:
6113 Paint processed pixels in white:
6119 @section lenscorrection
6121 Correct radial lens distortion
6123 This filter can be used to correct for radial distortion as can result from the use
6124 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
6125 one can use tools available for example as part of opencv or simply trial-and-error.
6126 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
6127 and extract the k1 and k2 coefficients from the resulting matrix.
6129 Note that effectively the same filter is available in the open-source tools Krita and
6130 Digikam from the KDE project.
6132 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
6133 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
6134 brightness distribution, so you may want to use both filters together in certain
6135 cases, though you will have to take care of ordering, i.e. whether vignetting should
6136 be applied before or after lens correction.
6140 The filter accepts the following options:
6144 Relative x-coordinate of the focal point of the image, and thereby the center of the
6145 distortion. This value has a range [0,1] and is expressed as fractions of the image
6148 Relative y-coordinate of the focal point of the image, and thereby the center of the
6149 distortion. This value has a range [0,1] and is expressed as fractions of the image
6152 Coefficient of the quadratic correction term. 0.5 means no correction.
6154 Coefficient of the double quadratic correction term. 0.5 means no correction.
6157 The formula that generates the correction is:
6159 @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)
6161 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
6162 distances from the focal point in the source and target images, respectively.
6167 Apply a 3D LUT to an input video.
6169 The filter accepts the following options:
6173 Set the 3D LUT file name.
6175 Currently supported formats:
6187 Select interpolation mode.
6189 Available values are:
6193 Use values from the nearest defined point.
6195 Interpolate values using the 8 points defining a cube.
6197 Interpolate values using a tetrahedron.
6201 @section lut, lutrgb, lutyuv
6203 Compute a look-up table for binding each pixel component input value
6204 to an output value, and apply it to the input video.
6206 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
6207 to an RGB input video.
6209 These filters accept the following parameters:
6212 set first pixel component expression
6214 set second pixel component expression
6216 set third pixel component expression
6218 set fourth pixel component expression, corresponds to the alpha component
6221 set red component expression
6223 set green component expression
6225 set blue component expression
6227 alpha component expression
6230 set Y/luminance component expression
6232 set U/Cb component expression
6234 set V/Cr component expression
6237 Each of them specifies the expression to use for computing the lookup table for
6238 the corresponding pixel component values.
6240 The exact component associated to each of the @var{c*} options depends on the
6243 The @var{lut} filter requires either YUV or RGB pixel formats in input,
6244 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
6246 The expressions can contain the following constants and functions:
6251 The input width and height.
6254 The input value for the pixel component.
6257 The input value, clipped to the @var{minval}-@var{maxval} range.
6260 The maximum value for the pixel component.
6263 The minimum value for the pixel component.
6266 The negated value for the pixel component value, clipped to the
6267 @var{minval}-@var{maxval} range; it corresponds to the expression
6268 "maxval-clipval+minval".
6271 The computed value in @var{val}, clipped to the
6272 @var{minval}-@var{maxval} range.
6274 @item gammaval(gamma)
6275 The computed gamma correction value of the pixel component value,
6276 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
6278 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
6282 All expressions default to "val".
6284 @subsection Examples
6290 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
6291 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
6294 The above is the same as:
6296 lutrgb="r=negval:g=negval:b=negval"
6297 lutyuv="y=negval:u=negval:v=negval"
6307 Remove chroma components, turning the video into a graytone image:
6309 lutyuv="u=128:v=128"
6313 Apply a luma burning effect:
6319 Remove green and blue components:
6325 Set a constant alpha channel value on input:
6327 format=rgba,lutrgb=a="maxval-minval/2"
6331 Correct luminance gamma by a factor of 0.5:
6333 lutyuv=y=gammaval(0.5)
6337 Discard least significant bits of luma:
6339 lutyuv=y='bitand(val, 128+64+32)'
6343 @section mergeplanes
6345 Merge color channel components from several video streams.
6347 The filter accepts up to 4 input streams, and merge selected input
6348 planes to the output video.
6350 This filter accepts the following options:
6353 Set input to output plane mapping. Default is @code{0}.
6355 The mappings is specified as a bitmap. It should be specified as a
6356 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
6357 mapping for the first plane of the output stream. 'A' sets the number of
6358 the input stream to use (from 0 to 3), and 'a' the plane number of the
6359 corresponding input to use (from 0 to 3). The rest of the mappings is
6360 similar, 'Bb' describes the mapping for the output stream second
6361 plane, 'Cc' describes the mapping for the output stream third plane and
6362 'Dd' describes the mapping for the output stream fourth plane.
6365 Set output pixel format. Default is @code{yuva444p}.
6368 @subsection Examples
6372 Merge three gray video streams of same width and height into single video stream:
6374 [a0][a1][a2]mergeplanes=0x001020:yuv444p
6378 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
6380 [a0][a1]mergeplanes=0x00010210:yuva444p
6384 Swap Y and A plane in yuva444p stream:
6386 format=yuva444p,mergeplanes=0x03010200:yuva444p
6390 Swap U and V plane in yuv420p stream:
6392 format=yuv420p,mergeplanes=0x000201:yuv420p
6396 Cast a rgb24 clip to yuv444p:
6398 format=rgb24,mergeplanes=0x000102:yuv444p
6404 Apply motion-compensation deinterlacing.
6406 It needs one field per frame as input and must thus be used together
6407 with yadif=1/3 or equivalent.
6409 This filter accepts the following options:
6412 Set the deinterlacing mode.
6414 It accepts one of the following values:
6419 use iterative motion estimation
6421 like @samp{slow}, but use multiple reference frames.
6423 Default value is @samp{fast}.
6426 Set the picture field parity assumed for the input video. It must be
6427 one of the following values:
6431 assume top field first
6433 assume bottom field first
6436 Default value is @samp{bff}.
6439 Set per-block quantization parameter (QP) used by the internal
6442 Higher values should result in a smoother motion vector field but less
6443 optimal individual vectors. Default value is 1.
6448 Drop frames that do not differ greatly from the previous frame in
6449 order to reduce frame rate.
6451 The main use of this filter is for very-low-bitrate encoding
6452 (e.g. streaming over dialup modem), but it could in theory be used for
6453 fixing movies that were inverse-telecined incorrectly.
6455 A description of the accepted options follows.
6459 Set the maximum number of consecutive frames which can be dropped (if
6460 positive), or the minimum interval between dropped frames (if
6461 negative). If the value is 0, the frame is dropped unregarding the
6462 number of previous sequentially dropped frames.
6469 Set the dropping threshold values.
6471 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
6472 represent actual pixel value differences, so a threshold of 64
6473 corresponds to 1 unit of difference for each pixel, or the same spread
6474 out differently over the block.
6476 A frame is a candidate for dropping if no 8x8 blocks differ by more
6477 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
6478 meaning the whole image) differ by more than a threshold of @option{lo}.
6480 Default value for @option{hi} is 64*12, default value for @option{lo} is
6481 64*5, and default value for @option{frac} is 0.33.
6489 It accepts an integer in input; if non-zero it negates the
6490 alpha component (if available). The default value in input is 0.
6494 Force libavfilter not to use any of the specified pixel formats for the
6495 input to the next filter.
6497 It accepts the following parameters:
6501 A '|'-separated list of pixel format names, such as
6502 apix_fmts=yuv420p|monow|rgb24".
6506 @subsection Examples
6510 Force libavfilter to use a format different from @var{yuv420p} for the
6511 input to the vflip filter:
6513 noformat=pix_fmts=yuv420p,vflip
6517 Convert the input video to any of the formats not contained in the list:
6519 noformat=yuv420p|yuv444p|yuv410p
6525 Add noise on video input frame.
6527 The filter accepts the following options:
6535 Set noise seed for specific pixel component or all pixel components in case
6536 of @var{all_seed}. Default value is @code{123457}.
6538 @item all_strength, alls
6539 @item c0_strength, c0s
6540 @item c1_strength, c1s
6541 @item c2_strength, c2s
6542 @item c3_strength, c3s
6543 Set noise strength for specific pixel component or all pixel components in case
6544 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
6546 @item all_flags, allf
6551 Set pixel component flags or set flags for all components if @var{all_flags}.
6552 Available values for component flags are:
6555 averaged temporal noise (smoother)
6557 mix random noise with a (semi)regular pattern
6559 temporal noise (noise pattern changes between frames)
6561 uniform noise (gaussian otherwise)
6565 @subsection Examples
6567 Add temporal and uniform noise to input video:
6569 noise=alls=20:allf=t+u
6574 Pass the video source unchanged to the output.
6578 Apply a video transform using libopencv.
6580 To enable this filter, install the libopencv library and headers and
6581 configure FFmpeg with @code{--enable-libopencv}.
6583 It accepts the following parameters:
6588 The name of the libopencv filter to apply.
6591 The parameters to pass to the libopencv filter. If not specified, the default
6596 Refer to the official libopencv documentation for more precise
6598 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
6600 Several libopencv filters are supported; see the following subsections.
6605 Dilate an image by using a specific structuring element.
6606 It corresponds to the libopencv function @code{cvDilate}.
6608 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
6610 @var{struct_el} represents a structuring element, and has the syntax:
6611 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
6613 @var{cols} and @var{rows} represent the number of columns and rows of
6614 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
6615 point, and @var{shape} the shape for the structuring element. @var{shape}
6616 must be "rect", "cross", "ellipse", or "custom".
6618 If the value for @var{shape} is "custom", it must be followed by a
6619 string of the form "=@var{filename}". The file with name
6620 @var{filename} is assumed to represent a binary image, with each
6621 printable character corresponding to a bright pixel. When a custom
6622 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
6623 or columns and rows of the read file are assumed instead.
6625 The default value for @var{struct_el} is "3x3+0x0/rect".
6627 @var{nb_iterations} specifies the number of times the transform is
6628 applied to the image, and defaults to 1.
6632 # Use the default values
6635 # Dilate using a structuring element with a 5x5 cross, iterating two times
6636 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
6638 # Read the shape from the file diamond.shape, iterating two times.
6639 # The file diamond.shape may contain a pattern of characters like this
6645 # The specified columns and rows are ignored
6646 # but the anchor point coordinates are not
6647 ocv=dilate:0x0+2x2/custom=diamond.shape|2
6652 Erode an image by using a specific structuring element.
6653 It corresponds to the libopencv function @code{cvErode}.
6655 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
6656 with the same syntax and semantics as the @ref{dilate} filter.
6660 Smooth the input video.
6662 The filter takes the following parameters:
6663 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
6665 @var{type} is the type of smooth filter to apply, and must be one of
6666 the following values: "blur", "blur_no_scale", "median", "gaussian",
6667 or "bilateral". The default value is "gaussian".
6669 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
6670 depend on the smooth type. @var{param1} and
6671 @var{param2} accept integer positive values or 0. @var{param3} and
6672 @var{param4} accept floating point values.
6674 The default value for @var{param1} is 3. The default value for the
6675 other parameters is 0.
6677 These parameters correspond to the parameters assigned to the
6678 libopencv function @code{cvSmooth}.
6683 Overlay one video on top of another.
6685 It takes two inputs and has one output. The first input is the "main"
6686 video on which the second input is overlaid.
6688 It accepts the following parameters:
6690 A description of the accepted options follows.
6695 Set the expression for the x and y coordinates of the overlaid video
6696 on the main video. Default value is "0" for both expressions. In case
6697 the expression is invalid, it is set to a huge value (meaning that the
6698 overlay will not be displayed within the output visible area).
6701 The action to take when EOF is encountered on the secondary input; it accepts
6702 one of the following values:
6706 Repeat the last frame (the default).
6710 Pass the main input through.
6714 Set when the expressions for @option{x}, and @option{y} are evaluated.
6716 It accepts the following values:
6719 only evaluate expressions once during the filter initialization or
6720 when a command is processed
6723 evaluate expressions for each incoming frame
6726 Default value is @samp{frame}.
6729 If set to 1, force the output to terminate when the shortest input
6730 terminates. Default value is 0.
6733 Set the format for the output video.
6735 It accepts the following values:
6750 Default value is @samp{yuv420}.
6752 @item rgb @emph{(deprecated)}
6753 If set to 1, force the filter to accept inputs in the RGB
6754 color space. Default value is 0. This option is deprecated, use
6755 @option{format} instead.
6758 If set to 1, force the filter to draw the last overlay frame over the
6759 main input until the end of the stream. A value of 0 disables this
6760 behavior. Default value is 1.
6763 The @option{x}, and @option{y} expressions can contain the following
6769 The main input width and height.
6773 The overlay input width and height.
6777 The computed values for @var{x} and @var{y}. They are evaluated for
6782 horizontal and vertical chroma subsample values of the output
6783 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6787 the number of input frame, starting from 0
6790 the position in the file of the input frame, NAN if unknown
6793 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6797 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6798 when evaluation is done @emph{per frame}, and will evaluate to NAN
6799 when @option{eval} is set to @samp{init}.
6801 Be aware that frames are taken from each input video in timestamp
6802 order, hence, if their initial timestamps differ, it is a good idea
6803 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6804 have them begin in the same zero timestamp, as the example for
6805 the @var{movie} filter does.
6807 You can chain together more overlays but you should test the
6808 efficiency of such approach.
6810 @subsection Commands
6812 This filter supports the following commands:
6816 Modify the x and y of the overlay input.
6817 The command accepts the same syntax of the corresponding option.
6819 If the specified expression is not valid, it is kept at its current
6823 @subsection Examples
6827 Draw the overlay at 10 pixels from the bottom right corner of the main
6830 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6833 Using named options the example above becomes:
6835 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6839 Insert a transparent PNG logo in the bottom left corner of the input,
6840 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6842 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6846 Insert 2 different transparent PNG logos (second logo on bottom
6847 right corner) using the @command{ffmpeg} tool:
6849 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
6853 Add a transparent color layer on top of the main video; @code{WxH}
6854 must specify the size of the main input to the overlay filter:
6856 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6860 Play an original video and a filtered version (here with the deshake
6861 filter) side by side using the @command{ffplay} tool:
6863 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6866 The above command is the same as:
6868 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6872 Make a sliding overlay appearing from the left to the right top part of the
6873 screen starting since time 2:
6875 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6879 Compose output by putting two input videos side to side:
6881 ffmpeg -i left.avi -i right.avi -filter_complex "
6882 nullsrc=size=200x100 [background];
6883 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6884 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6885 [background][left] overlay=shortest=1 [background+left];
6886 [background+left][right] overlay=shortest=1:x=100 [left+right]
6891 Mask 10-20 seconds of a video by applying the delogo filter to a section
6893 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6894 -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]'
6899 Chain several overlays in cascade:
6901 nullsrc=s=200x200 [bg];
6902 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6903 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6904 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6905 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6906 [in3] null, [mid2] overlay=100:100 [out0]
6913 Apply Overcomplete Wavelet denoiser.
6915 The filter accepts the following options:
6921 Larger depth values will denoise lower frequency components more, but
6922 slow down filtering.
6924 Must be an int in the range 8-16, default is @code{8}.
6926 @item luma_strength, ls
6929 Must be a double value in the range 0-1000, default is @code{1.0}.
6931 @item chroma_strength, cs
6932 Set chroma strength.
6934 Must be a double value in the range 0-1000, default is @code{1.0}.
6939 Add paddings to the input image, and place the original input at the
6940 provided @var{x}, @var{y} coordinates.
6942 It accepts the following parameters:
6947 Specify an expression for the size of the output image with the
6948 paddings added. If the value for @var{width} or @var{height} is 0, the
6949 corresponding input size is used for the output.
6951 The @var{width} expression can reference the value set by the
6952 @var{height} expression, and vice versa.
6954 The default value of @var{width} and @var{height} is 0.
6958 Specify the offsets to place the input image at within the padded area,
6959 with respect to the top/left border of the output image.
6961 The @var{x} expression can reference the value set by the @var{y}
6962 expression, and vice versa.
6964 The default value of @var{x} and @var{y} is 0.
6967 Specify the color of the padded area. For the syntax of this option,
6968 check the "Color" section in the ffmpeg-utils manual.
6970 The default value of @var{color} is "black".
6973 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6974 options are expressions containing the following constants:
6979 The input video width and height.
6983 These are the same as @var{in_w} and @var{in_h}.
6987 The output width and height (the size of the padded area), as
6988 specified by the @var{width} and @var{height} expressions.
6992 These are the same as @var{out_w} and @var{out_h}.
6996 The x and y offsets as specified by the @var{x} and @var{y}
6997 expressions, or NAN if not yet specified.
7000 same as @var{iw} / @var{ih}
7003 input sample aspect ratio
7006 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
7010 The horizontal and vertical chroma subsample values. For example for the
7011 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7014 @subsection Examples
7018 Add paddings with the color "violet" to the input video. The output video
7019 size is 640x480, and the top-left corner of the input video is placed at
7022 pad=640:480:0:40:violet
7025 The example above is equivalent to the following command:
7027 pad=width=640:height=480:x=0:y=40:color=violet
7031 Pad the input to get an output with dimensions increased by 3/2,
7032 and put the input video at the center of the padded area:
7034 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
7038 Pad the input to get a squared output with size equal to the maximum
7039 value between the input width and height, and put the input video at
7040 the center of the padded area:
7042 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
7046 Pad the input to get a final w/h ratio of 16:9:
7048 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
7052 In case of anamorphic video, in order to set the output display aspect
7053 correctly, it is necessary to use @var{sar} in the expression,
7054 according to the relation:
7056 (ih * X / ih) * sar = output_dar
7057 X = output_dar / sar
7060 Thus the previous example needs to be modified to:
7062 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
7066 Double the output size and put the input video in the bottom-right
7067 corner of the output padded area:
7069 pad="2*iw:2*ih:ow-iw:oh-ih"
7076 Generate one palette for a whole video stream.
7078 It accepts the following options:
7082 Set the maximum number of colors to quantize in the palette.
7083 Note: the palette will still contain 256 colors; the unused palette entries
7086 @item reserve_transparent
7087 Create a palette of 255 colors maximum and reserve the last one for
7088 transparency. Reserving the transparency color is useful for GIF optimization.
7089 If not set, the maximum of colors in the palette will be 256. You probably want
7090 to disable this option for a standalone image.
7094 Set statistics mode.
7096 It accepts the following values:
7099 Compute full frame histograms.
7101 Compute histograms only for the part that differs from previous frame. This
7102 might be relevant to give more importance to the moving part of your input if
7103 the background is static.
7106 Default value is @var{full}.
7109 The filter also exports the frame metadata @code{lavfi.color_quant_ratio}
7110 (@code{nb_color_in / nb_color_out}) which you can use to evaluate the degree of
7111 color quantization of the palette. This information is also visible at
7112 @var{info} logging level.
7114 @subsection Examples
7118 Generate a representative palette of a given video using @command{ffmpeg}:
7120 ffmpeg -i input.mkv -vf palettegen palette.png
7126 Use a palette to downsample an input video stream.
7128 The filter takes two inputs: one video stream and a palette. The palette must
7129 be a 256 pixels image.
7131 It accepts the following options:
7135 Select dithering mode. Available algorithms are:
7138 Ordered 8x8 bayer dithering (deterministic)
7140 Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
7141 Note: this dithering is sometimes considered "wrong" and is included as a
7143 @item floyd_steinberg
7144 Floyd and Steingberg dithering (error diffusion)
7146 Frankie Sierra dithering v2 (error diffusion)
7148 Frankie Sierra dithering v2 "Lite" (error diffusion)
7151 Default is @var{sierra2_4a}.
7154 When @var{bayer} dithering is selected, this option defines the scale of the
7155 pattern (how much the crosshatch pattern is visible). A low value means more
7156 visible pattern for less banding, and higher value means less visible pattern
7157 at the cost of more banding.
7159 The option must be an integer value in the range [0,5]. Default is @var{2}.
7162 If set, define the zone to process
7166 Only the changing rectangle will be reprocessed. This is similar to GIF
7167 cropping/offsetting compression mechanism. This option can be useful for speed
7168 if only a part of the image is changing, and has use cases such as limiting the
7169 scope of the error diffusal @option{dither} to the rectangle that bounds the
7170 moving scene (it leads to more deterministic output if the scene doesn't change
7171 much, and as a result less moving noise and better GIF compression).
7174 Default is @var{none}.
7177 @subsection Examples
7181 Use a palette (generated for example with @ref{palettegen}) to encode a GIF
7182 using @command{ffmpeg}:
7184 ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
7188 @section perspective
7190 Correct perspective of video not recorded perpendicular to the screen.
7192 A description of the accepted parameters follows.
7203 Set coordinates expression for top left, top right, bottom left and bottom right corners.
7204 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
7205 If the @code{sense} option is set to @code{source}, then the specified points will be sent
7206 to the corners of the destination. If the @code{sense} option is set to @code{destination},
7207 then the corners of the source will be sent to the specified coordinates.
7209 The expressions can use the following variables:
7214 the width and height of video frame.
7218 Set interpolation for perspective correction.
7220 It accepts the following values:
7226 Default value is @samp{linear}.
7229 Set interpretation of coordinate options.
7231 It accepts the following values:
7235 Send point in the source specified by the given coordinates to
7236 the corners of the destination.
7238 @item 1, destination
7240 Send the corners of the source to the point in the destination specified
7241 by the given coordinates.
7243 Default value is @samp{source}.
7249 Delay interlaced video by one field time so that the field order changes.
7251 The intended use is to fix PAL movies that have been captured with the
7252 opposite field order to the film-to-video transfer.
7254 A description of the accepted parameters follows.
7260 It accepts the following values:
7263 Capture field order top-first, transfer bottom-first.
7264 Filter will delay the bottom field.
7267 Capture field order bottom-first, transfer top-first.
7268 Filter will delay the top field.
7271 Capture and transfer with the same field order. This mode only exists
7272 for the documentation of the other options to refer to, but if you
7273 actually select it, the filter will faithfully do nothing.
7276 Capture field order determined automatically by field flags, transfer
7278 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
7279 basis using field flags. If no field information is available,
7280 then this works just like @samp{u}.
7283 Capture unknown or varying, transfer opposite.
7284 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
7285 analyzing the images and selecting the alternative that produces best
7286 match between the fields.
7289 Capture top-first, transfer unknown or varying.
7290 Filter selects among @samp{t} and @samp{p} using image analysis.
7293 Capture bottom-first, transfer unknown or varying.
7294 Filter selects among @samp{b} and @samp{p} using image analysis.
7297 Capture determined by field flags, transfer unknown or varying.
7298 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
7299 image analysis. If no field information is available, then this works just
7300 like @samp{U}. This is the default mode.
7303 Both capture and transfer unknown or varying.
7304 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
7308 @section pixdesctest
7310 Pixel format descriptor test filter, mainly useful for internal
7311 testing. The output video should be equal to the input video.
7315 format=monow, pixdesctest
7318 can be used to test the monowhite pixel format descriptor definition.
7322 Enable the specified chain of postprocessing subfilters using libpostproc. This
7323 library should be automatically selected with a GPL build (@code{--enable-gpl}).
7324 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
7325 Each subfilter and some options have a short and a long name that can be used
7326 interchangeably, i.e. dr/dering are the same.
7328 The filters accept the following options:
7332 Set postprocessing subfilters string.
7335 All subfilters share common options to determine their scope:
7339 Honor the quality commands for this subfilter.
7342 Do chrominance filtering, too (default).
7345 Do luminance filtering only (no chrominance).
7348 Do chrominance filtering only (no luminance).
7351 These options can be appended after the subfilter name, separated by a '|'.
7353 Available subfilters are:
7356 @item hb/hdeblock[|difference[|flatness]]
7357 Horizontal deblocking filter
7360 Difference factor where higher values mean more deblocking (default: @code{32}).
7362 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7365 @item vb/vdeblock[|difference[|flatness]]
7366 Vertical deblocking filter
7369 Difference factor where higher values mean more deblocking (default: @code{32}).
7371 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7374 @item ha/hadeblock[|difference[|flatness]]
7375 Accurate horizontal deblocking filter
7378 Difference factor where higher values mean more deblocking (default: @code{32}).
7380 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7383 @item va/vadeblock[|difference[|flatness]]
7384 Accurate vertical deblocking filter
7387 Difference factor where higher values mean more deblocking (default: @code{32}).
7389 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7393 The horizontal and vertical deblocking filters share the difference and
7394 flatness values so you cannot set different horizontal and vertical
7399 Experimental horizontal deblocking filter
7402 Experimental vertical deblocking filter
7407 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
7410 larger -> stronger filtering
7412 larger -> stronger filtering
7414 larger -> stronger filtering
7417 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
7420 Stretch luminance to @code{0-255}.
7423 @item lb/linblenddeint
7424 Linear blend deinterlacing filter that deinterlaces the given block by
7425 filtering all lines with a @code{(1 2 1)} filter.
7427 @item li/linipoldeint
7428 Linear interpolating deinterlacing filter that deinterlaces the given block by
7429 linearly interpolating every second line.
7431 @item ci/cubicipoldeint
7432 Cubic interpolating deinterlacing filter deinterlaces the given block by
7433 cubically interpolating every second line.
7435 @item md/mediandeint
7436 Median deinterlacing filter that deinterlaces the given block by applying a
7437 median filter to every second line.
7439 @item fd/ffmpegdeint
7440 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
7441 second line with a @code{(-1 4 2 4 -1)} filter.
7444 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
7445 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
7447 @item fq/forceQuant[|quantizer]
7448 Overrides the quantizer table from the input with the constant quantizer you
7456 Default pp filter combination (@code{hb|a,vb|a,dr|a})
7459 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
7462 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
7465 @subsection Examples
7469 Apply horizontal and vertical deblocking, deringing and automatic
7470 brightness/contrast:
7476 Apply default filters without brightness/contrast correction:
7482 Apply default filters and temporal denoiser:
7484 pp=default/tmpnoise|1|2|3
7488 Apply deblocking on luminance only, and switch vertical deblocking on or off
7489 automatically depending on available CPU time:
7496 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
7497 similar to spp = 6 with 7 point DCT, where only the center sample is
7500 The filter accepts the following options:
7504 Force a constant quantization parameter. It accepts an integer in range
7505 0 to 63. If not set, the filter will use the QP from the video stream
7509 Set thresholding mode. Available modes are:
7513 Set hard thresholding.
7515 Set soft thresholding (better de-ringing effect, but likely blurrier).
7517 Set medium thresholding (good results, default).
7523 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
7524 Ratio) between two input videos.
7526 This filter takes in input two input videos, the first input is
7527 considered the "main" source and is passed unchanged to the
7528 output. The second input is used as a "reference" video for computing
7531 Both video inputs must have the same resolution and pixel format for
7532 this filter to work correctly. Also it assumes that both inputs
7533 have the same number of frames, which are compared one by one.
7535 The obtained average PSNR is printed through the logging system.
7537 The filter stores the accumulated MSE (mean squared error) of each
7538 frame, and at the end of the processing it is averaged across all frames
7539 equally, and the following formula is applied to obtain the PSNR:
7542 PSNR = 10*log10(MAX^2/MSE)
7545 Where MAX is the average of the maximum values of each component of the
7548 The description of the accepted parameters follows.
7552 If specified the filter will use the named file to save the PSNR of
7553 each individual frame.
7556 The file printed if @var{stats_file} is selected, contains a sequence of
7557 key/value pairs of the form @var{key}:@var{value} for each compared
7560 A description of each shown parameter follows:
7564 sequential number of the input frame, starting from 1
7567 Mean Square Error pixel-by-pixel average difference of the compared
7568 frames, averaged over all the image components.
7570 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
7571 Mean Square Error pixel-by-pixel average difference of the compared
7572 frames for the component specified by the suffix.
7574 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
7575 Peak Signal to Noise ratio of the compared frames for the component
7576 specified by the suffix.
7581 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
7582 [main][ref] psnr="stats_file=stats.log" [out]
7585 On this example the input file being processed is compared with the
7586 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
7587 is stored in @file{stats.log}.
7592 Pulldown reversal (inverse telecine) filter, capable of handling mixed
7593 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
7596 The pullup filter is designed to take advantage of future context in making
7597 its decisions. This filter is stateless in the sense that it does not lock
7598 onto a pattern to follow, but it instead looks forward to the following
7599 fields in order to identify matches and rebuild progressive frames.
7601 To produce content with an even framerate, insert the fps filter after
7602 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
7603 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
7605 The filter accepts the following options:
7612 These options set the amount of "junk" to ignore at the left, right, top, and
7613 bottom of the image, respectively. Left and right are in units of 8 pixels,
7614 while top and bottom are in units of 2 lines.
7615 The default is 8 pixels on each side.
7618 Set the strict breaks. Setting this option to 1 will reduce the chances of
7619 filter generating an occasional mismatched frame, but it may also cause an
7620 excessive number of frames to be dropped during high motion sequences.
7621 Conversely, setting it to -1 will make filter match fields more easily.
7622 This may help processing of video where there is slight blurring between
7623 the fields, but may also cause there to be interlaced frames in the output.
7624 Default value is @code{0}.
7627 Set the metric plane to use. It accepts the following values:
7633 Use chroma blue plane.
7636 Use chroma red plane.
7639 This option may be set to use chroma plane instead of the default luma plane
7640 for doing filter's computations. This may improve accuracy on very clean
7641 source material, but more likely will decrease accuracy, especially if there
7642 is chroma noise (rainbow effect) or any grayscale video.
7643 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
7644 load and make pullup usable in realtime on slow machines.
7647 For best results (without duplicated frames in the output file) it is
7648 necessary to change the output frame rate. For example, to inverse
7649 telecine NTSC input:
7651 ffmpeg -i input -vf pullup -r 24000/1001 ...
7656 Change video quantization parameters (QP).
7658 The filter accepts the following option:
7662 Set expression for quantization parameter.
7665 The expression is evaluated through the eval API and can contain, among others,
7666 the following constants:
7670 1 if index is not 129, 0 otherwise.
7673 Sequentional index starting from -129 to 128.
7676 @subsection Examples
7688 Suppress a TV station logo, using an image file to determine which
7689 pixels comprise the logo. It works by filling in the pixels that
7690 comprise the logo with neighboring pixels.
7692 The filter accepts the following options:
7696 Set the filter bitmap file, which can be any image format supported by
7697 libavformat. The width and height of the image file must match those of the
7698 video stream being processed.
7701 Pixels in the provided bitmap image with a value of zero are not
7702 considered part of the logo, non-zero pixels are considered part of
7703 the logo. If you use white (255) for the logo and black (0) for the
7704 rest, you will be safe. For making the filter bitmap, it is
7705 recommended to take a screen capture of a black frame with the logo
7706 visible, and then using a threshold filter followed by the erode
7707 filter once or twice.
7709 If needed, little splotches can be fixed manually. Remember that if
7710 logo pixels are not covered, the filter quality will be much
7711 reduced. Marking too many pixels as part of the logo does not hurt as
7712 much, but it will increase the amount of blurring needed to cover over
7713 the image and will destroy more information than necessary, and extra
7714 pixels will slow things down on a large logo.
7716 @section repeatfields
7718 This filter uses the repeat_field flag from the Video ES headers and hard repeats
7719 fields based on its value.
7723 Rotate video by an arbitrary angle expressed in radians.
7725 The filter accepts the following options:
7727 A description of the optional parameters follows.
7730 Set an expression for the angle by which to rotate the input video
7731 clockwise, expressed as a number of radians. A negative value will
7732 result in a counter-clockwise rotation. By default it is set to "0".
7734 This expression is evaluated for each frame.
7737 Set the output width expression, default value is "iw".
7738 This expression is evaluated just once during configuration.
7741 Set the output height expression, default value is "ih".
7742 This expression is evaluated just once during configuration.
7745 Enable bilinear interpolation if set to 1, a value of 0 disables
7746 it. Default value is 1.
7749 Set the color used to fill the output area not covered by the rotated
7750 image. For the general syntax of this option, check the "Color" section in the
7751 ffmpeg-utils manual. If the special value "none" is selected then no
7752 background is printed (useful for example if the background is never shown).
7754 Default value is "black".
7757 The expressions for the angle and the output size can contain the
7758 following constants and functions:
7762 sequential number of the input frame, starting from 0. It is always NAN
7763 before the first frame is filtered.
7766 time in seconds of the input frame, it is set to 0 when the filter is
7767 configured. It is always NAN before the first frame is filtered.
7771 horizontal and vertical chroma subsample values. For example for the
7772 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7776 the input video width and height
7780 the output width and height, that is the size of the padded area as
7781 specified by the @var{width} and @var{height} expressions
7785 the minimal width/height required for completely containing the input
7786 video rotated by @var{a} radians.
7788 These are only available when computing the @option{out_w} and
7789 @option{out_h} expressions.
7792 @subsection Examples
7796 Rotate the input by PI/6 radians clockwise:
7802 Rotate the input by PI/6 radians counter-clockwise:
7808 Rotate the input by 45 degrees clockwise:
7814 Apply a constant rotation with period T, starting from an angle of PI/3:
7816 rotate=PI/3+2*PI*t/T
7820 Make the input video rotation oscillating with a period of T
7821 seconds and an amplitude of A radians:
7823 rotate=A*sin(2*PI/T*t)
7827 Rotate the video, output size is chosen so that the whole rotating
7828 input video is always completely contained in the output:
7830 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
7834 Rotate the video, reduce the output size so that no background is ever
7837 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
7841 @subsection Commands
7843 The filter supports the following commands:
7847 Set the angle expression.
7848 The command accepts the same syntax of the corresponding option.
7850 If the specified expression is not valid, it is kept at its current
7856 Apply Shape Adaptive Blur.
7858 The filter accepts the following options:
7861 @item luma_radius, lr
7862 Set luma blur filter strength, must be a value in range 0.1-4.0, default
7863 value is 1.0. A greater value will result in a more blurred image, and
7864 in slower processing.
7866 @item luma_pre_filter_radius, lpfr
7867 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
7870 @item luma_strength, ls
7871 Set luma maximum difference between pixels to still be considered, must
7872 be a value in the 0.1-100.0 range, default value is 1.0.
7874 @item chroma_radius, cr
7875 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
7876 greater value will result in a more blurred image, and in slower
7879 @item chroma_pre_filter_radius, cpfr
7880 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
7882 @item chroma_strength, cs
7883 Set chroma maximum difference between pixels to still be considered,
7884 must be a value in the 0.1-100.0 range.
7887 Each chroma option value, if not explicitly specified, is set to the
7888 corresponding luma option value.
7893 Scale (resize) the input video, using the libswscale library.
7895 The scale filter forces the output display aspect ratio to be the same
7896 of the input, by changing the output sample aspect ratio.
7898 If the input image format is different from the format requested by
7899 the next filter, the scale filter will convert the input to the
7903 The filter accepts the following options, or any of the options
7904 supported by the libswscale scaler.
7906 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
7907 the complete list of scaler options.
7912 Set the output video dimension expression. Default value is the input
7915 If the value is 0, the input width is used for the output.
7917 If one of the values is -1, the scale filter will use a value that
7918 maintains the aspect ratio of the input image, calculated from the
7919 other specified dimension. If both of them are -1, the input size is
7922 If one of the values is -n with n > 1, the scale filter will also use a value
7923 that maintains the aspect ratio of the input image, calculated from the other
7924 specified dimension. After that it will, however, make sure that the calculated
7925 dimension is divisible by n and adjust the value if necessary.
7927 See below for the list of accepted constants for use in the dimension
7931 Set the interlacing mode. It accepts the following values:
7935 Force interlaced aware scaling.
7938 Do not apply interlaced scaling.
7941 Select interlaced aware scaling depending on whether the source frames
7942 are flagged as interlaced or not.
7945 Default value is @samp{0}.
7948 Set libswscale scaling flags. See
7949 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7950 complete list of values. If not explicitly specified the filter applies
7954 Set the video size. For the syntax of this option, check the
7955 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
7957 @item in_color_matrix
7958 @item out_color_matrix
7959 Set in/output YCbCr color space type.
7961 This allows the autodetected value to be overridden as well as allows forcing
7962 a specific value used for the output and encoder.
7964 If not specified, the color space type depends on the pixel format.
7970 Choose automatically.
7973 Format conforming to International Telecommunication Union (ITU)
7974 Recommendation BT.709.
7977 Set color space conforming to the United States Federal Communications
7978 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7981 Set color space conforming to:
7985 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7988 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7991 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7996 Set color space conforming to SMPTE ST 240:1999.
8001 Set in/output YCbCr sample range.
8003 This allows the autodetected value to be overridden as well as allows forcing
8004 a specific value used for the output and encoder. If not specified, the
8005 range depends on the pixel format. Possible values:
8009 Choose automatically.
8012 Set full range (0-255 in case of 8-bit luma).
8015 Set "MPEG" range (16-235 in case of 8-bit luma).
8018 @item force_original_aspect_ratio
8019 Enable decreasing or increasing output video width or height if necessary to
8020 keep the original aspect ratio. Possible values:
8024 Scale the video as specified and disable this feature.
8027 The output video dimensions will automatically be decreased if needed.
8030 The output video dimensions will automatically be increased if needed.
8034 One useful instance of this option is that when you know a specific device's
8035 maximum allowed resolution, you can use this to limit the output video to
8036 that, while retaining the aspect ratio. For example, device A allows
8037 1280x720 playback, and your video is 1920x800. Using this option (set it to
8038 decrease) and specifying 1280x720 to the command line makes the output
8041 Please note that this is a different thing than specifying -1 for @option{w}
8042 or @option{h}, you still need to specify the output resolution for this option
8047 The values of the @option{w} and @option{h} options are expressions
8048 containing the following constants:
8053 The input width and height
8057 These are the same as @var{in_w} and @var{in_h}.
8061 The output (scaled) width and height
8065 These are the same as @var{out_w} and @var{out_h}
8068 The same as @var{iw} / @var{ih}
8071 input sample aspect ratio
8074 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
8078 horizontal and vertical input chroma subsample values. For example for the
8079 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
8083 horizontal and vertical output chroma subsample values. For example for the
8084 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
8087 @subsection Examples
8091 Scale the input video to a size of 200x100
8096 This is equivalent to:
8107 Specify a size abbreviation for the output size:
8112 which can also be written as:
8118 Scale the input to 2x:
8124 The above is the same as:
8130 Scale the input to 2x with forced interlaced scaling:
8132 scale=2*iw:2*ih:interl=1
8136 Scale the input to half size:
8142 Increase the width, and set the height to the same size:
8155 Increase the height, and set the width to 3/2 of the height:
8157 scale=w=3/2*oh:h=3/5*ih
8161 Increase the size, making the size a multiple of the chroma
8164 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
8168 Increase the width to a maximum of 500 pixels,
8169 keeping the same aspect ratio as the input:
8171 scale=w='min(500\, iw*3/2):h=-1'
8175 @section separatefields
8177 The @code{separatefields} takes a frame-based video input and splits
8178 each frame into its components fields, producing a new half height clip
8179 with twice the frame rate and twice the frame count.
8181 This filter use field-dominance information in frame to decide which
8182 of each pair of fields to place first in the output.
8183 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
8185 @section setdar, setsar
8187 The @code{setdar} filter sets the Display Aspect Ratio for the filter
8190 This is done by changing the specified Sample (aka Pixel) Aspect
8191 Ratio, according to the following equation:
8193 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
8196 Keep in mind that the @code{setdar} filter does not modify the pixel
8197 dimensions of the video frame. Also, the display aspect ratio set by
8198 this filter may be changed by later filters in the filterchain,
8199 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
8202 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
8203 the filter output video.
8205 Note that as a consequence of the application of this filter, the
8206 output display aspect ratio will change according to the equation
8209 Keep in mind that the sample aspect ratio set by the @code{setsar}
8210 filter may be changed by later filters in the filterchain, e.g. if
8211 another "setsar" or a "setdar" filter is applied.
8213 It accepts the following parameters:
8216 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
8217 Set the aspect ratio used by the filter.
8219 The parameter can be a floating point number string, an expression, or
8220 a string of the form @var{num}:@var{den}, where @var{num} and
8221 @var{den} are the numerator and denominator of the aspect ratio. If
8222 the parameter is not specified, it is assumed the value "0".
8223 In case the form "@var{num}:@var{den}" is used, the @code{:} character
8227 Set the maximum integer value to use for expressing numerator and
8228 denominator when reducing the expressed aspect ratio to a rational.
8229 Default value is @code{100}.
8233 The parameter @var{sar} is an expression containing
8234 the following constants:
8238 These are approximated values for the mathematical constants e
8239 (Euler's number), pi (Greek pi), and phi (the golden ratio).
8242 The input width and height.
8245 These are the same as @var{w} / @var{h}.
8248 The input sample aspect ratio.
8251 The input display aspect ratio. It is the same as
8252 (@var{w} / @var{h}) * @var{sar}.
8255 Horizontal and vertical chroma subsample values. For example, for the
8256 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
8259 @subsection Examples
8264 To change the display aspect ratio to 16:9, specify one of the following:
8272 To change the sample aspect ratio to 10:11, specify:
8278 To set a display aspect ratio of 16:9, and specify a maximum integer value of
8279 1000 in the aspect ratio reduction, use the command:
8281 setdar=ratio=16/9:max=1000
8289 Force field for the output video frame.
8291 The @code{setfield} filter marks the interlace type field for the
8292 output frames. It does not change the input frame, but only sets the
8293 corresponding property, which affects how the frame is treated by
8294 following filters (e.g. @code{fieldorder} or @code{yadif}).
8296 The filter accepts the following options:
8301 Available values are:
8305 Keep the same field property.
8308 Mark the frame as bottom-field-first.
8311 Mark the frame as top-field-first.
8314 Mark the frame as progressive.
8320 Show a line containing various information for each input video frame.
8321 The input video is not modified.
8323 The shown line contains a sequence of key/value pairs of the form
8324 @var{key}:@var{value}.
8326 The following values are shown in the output:
8330 The (sequential) number of the input frame, starting from 0.
8333 The Presentation TimeStamp of the input frame, expressed as a number of
8334 time base units. The time base unit depends on the filter input pad.
8337 The Presentation TimeStamp of the input frame, expressed as a number of
8341 The position of the frame in the input stream, or -1 if this information is
8342 unavailable and/or meaningless (for example in case of synthetic video).
8345 The pixel format name.
8348 The sample aspect ratio of the input frame, expressed in the form
8349 @var{num}/@var{den}.
8352 The size of the input frame. For the syntax of this option, check the
8353 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
8356 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
8357 for bottom field first).
8360 This is 1 if the frame is a key frame, 0 otherwise.
8363 The picture type of the input frame ("I" for an I-frame, "P" for a
8364 P-frame, "B" for a B-frame, or "?" for an unknown type).
8365 Also refer to the documentation of the @code{AVPictureType} enum and of
8366 the @code{av_get_picture_type_char} function defined in
8367 @file{libavutil/avutil.h}.
8370 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
8372 @item plane_checksum
8373 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
8374 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
8377 @section showpalette
8379 Displays the 256 colors palette of each frame. This filter is only relevant for
8380 @var{pal8} pixel format frames.
8382 It accepts the following option:
8386 Set the size of the box used to represent one palette color entry. Default is
8387 @code{30} (for a @code{30x30} pixel box).
8390 @section shuffleplanes
8392 Reorder and/or duplicate video planes.
8394 It accepts the following parameters:
8399 The index of the input plane to be used as the first output plane.
8402 The index of the input plane to be used as the second output plane.
8405 The index of the input plane to be used as the third output plane.
8408 The index of the input plane to be used as the fourth output plane.
8412 The first plane has the index 0. The default is to keep the input unchanged.
8414 Swap the second and third planes of the input:
8416 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
8419 @section signalstats
8420 Evaluate various visual metrics that assist in determining issues associated
8421 with the digitization of analog video media.
8423 By default the filter will log these metadata values:
8427 Display the minimal Y value contained within the input frame. Expressed in
8431 Display the Y value at the 10% percentile within the input frame. Expressed in
8435 Display the average Y value within the input frame. Expressed in range of
8439 Display the Y value at the 90% percentile within the input frame. Expressed in
8443 Display the maximum Y value contained within the input frame. Expressed in
8447 Display the minimal U value contained within the input frame. Expressed in
8451 Display the U value at the 10% percentile within the input frame. Expressed in
8455 Display the average U value within the input frame. Expressed in range of
8459 Display the U value at the 90% percentile within the input frame. Expressed in
8463 Display the maximum U value contained within the input frame. Expressed in
8467 Display the minimal V value contained within the input frame. Expressed in
8471 Display the V value at the 10% percentile within the input frame. Expressed in
8475 Display the average V value within the input frame. Expressed in range of
8479 Display the V value at the 90% percentile within the input frame. Expressed in
8483 Display the maximum V value contained within the input frame. Expressed in
8487 Display the minimal saturation value contained within the input frame.
8488 Expressed in range of [0-~181.02].
8491 Display the saturation value at the 10% percentile within the input frame.
8492 Expressed in range of [0-~181.02].
8495 Display the average saturation value within the input frame. Expressed in range
8499 Display the saturation value at the 90% percentile within the input frame.
8500 Expressed in range of [0-~181.02].
8503 Display the maximum saturation value contained within the input frame.
8504 Expressed in range of [0-~181.02].
8507 Display the median value for hue within the input frame. Expressed in range of
8511 Display the average value for hue within the input frame. Expressed in range of
8515 Display the average of sample value difference between all values of the Y
8516 plane in the current frame and corresponding values of the previous input frame.
8517 Expressed in range of [0-255].
8520 Display the average of sample value difference between all values of the U
8521 plane in the current frame and corresponding values of the previous input frame.
8522 Expressed in range of [0-255].
8525 Display the average of sample value difference between all values of the V
8526 plane in the current frame and corresponding values of the previous input frame.
8527 Expressed in range of [0-255].
8530 The filter accepts the following options:
8536 @option{stat} specify an additional form of image analysis.
8537 @option{out} output video with the specified type of pixel highlighted.
8539 Both options accept the following values:
8543 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
8544 unlike the neighboring pixels of the same field. Examples of temporal outliers
8545 include the results of video dropouts, head clogs, or tape tracking issues.
8548 Identify @var{vertical line repetition}. Vertical line repetition includes
8549 similar rows of pixels within a frame. In born-digital video vertical line
8550 repetition is common, but this pattern is uncommon in video digitized from an
8551 analog source. When it occurs in video that results from the digitization of an
8552 analog source it can indicate concealment from a dropout compensator.
8555 Identify pixels that fall outside of legal broadcast range.
8559 Set the highlight color for the @option{out} option. The default color is
8563 @subsection Examples
8567 Output data of various video metrics:
8569 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
8573 Output specific data about the minimum and maximum values of the Y plane per frame:
8575 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
8579 Playback video while highlighting pixels that are outside of broadcast range in red.
8581 ffplay example.mov -vf signalstats="out=brng:color=red"
8585 Playback video with signalstats metadata drawn over the frame.
8587 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
8590 The contents of signalstat_drawtext.txt used in the command are:
8593 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
8594 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
8595 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
8596 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
8604 Blur the input video without impacting the outlines.
8606 It accepts the following options:
8609 @item luma_radius, lr
8610 Set the luma radius. The option value must be a float number in
8611 the range [0.1,5.0] that specifies the variance of the gaussian filter
8612 used to blur the image (slower if larger). Default value is 1.0.
8614 @item luma_strength, ls
8615 Set the luma strength. The option value must be a float number
8616 in the range [-1.0,1.0] that configures the blurring. A value included
8617 in [0.0,1.0] will blur the image whereas a value included in
8618 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8620 @item luma_threshold, lt
8621 Set the luma threshold used as a coefficient to determine
8622 whether a pixel should be blurred or not. The option value must be an
8623 integer in the range [-30,30]. A value of 0 will filter all the image,
8624 a value included in [0,30] will filter flat areas and a value included
8625 in [-30,0] will filter edges. Default value is 0.
8627 @item chroma_radius, cr
8628 Set the chroma radius. The option value must be a float number in
8629 the range [0.1,5.0] that specifies the variance of the gaussian filter
8630 used to blur the image (slower if larger). Default value is 1.0.
8632 @item chroma_strength, cs
8633 Set the chroma strength. The option value must be a float number
8634 in the range [-1.0,1.0] that configures the blurring. A value included
8635 in [0.0,1.0] will blur the image whereas a value included in
8636 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8638 @item chroma_threshold, ct
8639 Set the chroma threshold used as a coefficient to determine
8640 whether a pixel should be blurred or not. The option value must be an
8641 integer in the range [-30,30]. A value of 0 will filter all the image,
8642 a value included in [0,30] will filter flat areas and a value included
8643 in [-30,0] will filter edges. Default value is 0.
8646 If a chroma option is not explicitly set, the corresponding luma value
8651 Convert between different stereoscopic image formats.
8653 The filters accept the following options:
8657 Set stereoscopic image format of input.
8659 Available values for input image formats are:
8662 side by side parallel (left eye left, right eye right)
8665 side by side crosseye (right eye left, left eye right)
8668 side by side parallel with half width resolution
8669 (left eye left, right eye right)
8672 side by side crosseye with half width resolution
8673 (right eye left, left eye right)
8676 above-below (left eye above, right eye below)
8679 above-below (right eye above, left eye below)
8682 above-below with half height resolution
8683 (left eye above, right eye below)
8686 above-below with half height resolution
8687 (right eye above, left eye below)
8690 alternating frames (left eye first, right eye second)
8693 alternating frames (right eye first, left eye second)
8695 Default value is @samp{sbsl}.
8699 Set stereoscopic image format of output.
8701 Available values for output image formats are all the input formats as well as:
8704 anaglyph red/blue gray
8705 (red filter on left eye, blue filter on right eye)
8708 anaglyph red/green gray
8709 (red filter on left eye, green filter on right eye)
8712 anaglyph red/cyan gray
8713 (red filter on left eye, cyan filter on right eye)
8716 anaglyph red/cyan half colored
8717 (red filter on left eye, cyan filter on right eye)
8720 anaglyph red/cyan color
8721 (red filter on left eye, cyan filter on right eye)
8724 anaglyph red/cyan color optimized with the least squares projection of dubois
8725 (red filter on left eye, cyan filter on right eye)
8728 anaglyph green/magenta gray
8729 (green filter on left eye, magenta filter on right eye)
8732 anaglyph green/magenta half colored
8733 (green filter on left eye, magenta filter on right eye)
8736 anaglyph green/magenta colored
8737 (green filter on left eye, magenta filter on right eye)
8740 anaglyph green/magenta color optimized with the least squares projection of dubois
8741 (green filter on left eye, magenta filter on right eye)
8744 anaglyph yellow/blue gray
8745 (yellow filter on left eye, blue filter on right eye)
8748 anaglyph yellow/blue half colored
8749 (yellow filter on left eye, blue filter on right eye)
8752 anaglyph yellow/blue colored
8753 (yellow filter on left eye, blue filter on right eye)
8756 anaglyph yellow/blue color optimized with the least squares projection of dubois
8757 (yellow filter on left eye, blue filter on right eye)
8760 interleaved rows (left eye has top row, right eye starts on next row)
8763 interleaved rows (right eye has top row, left eye starts on next row)
8766 mono output (left eye only)
8769 mono output (right eye only)
8772 Default value is @samp{arcd}.
8775 @subsection Examples
8779 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
8785 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
8794 Apply a simple postprocessing filter that compresses and decompresses the image
8795 at several (or - in the case of @option{quality} level @code{6} - all) shifts
8796 and average the results.
8798 The filter accepts the following options:
8802 Set quality. This option defines the number of levels for averaging. It accepts
8803 an integer in the range 0-6. If set to @code{0}, the filter will have no
8804 effect. A value of @code{6} means the higher quality. For each increment of
8805 that value the speed drops by a factor of approximately 2. Default value is
8809 Force a constant quantization parameter. If not set, the filter will use the QP
8810 from the video stream (if available).
8813 Set thresholding mode. Available modes are:
8817 Set hard thresholding (default).
8819 Set soft thresholding (better de-ringing effect, but likely blurrier).
8823 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8824 option may cause flicker since the B-Frames have often larger QP. Default is
8825 @code{0} (not enabled).
8831 Draw subtitles on top of input video using the libass library.
8833 To enable compilation of this filter you need to configure FFmpeg with
8834 @code{--enable-libass}. This filter also requires a build with libavcodec and
8835 libavformat to convert the passed subtitles file to ASS (Advanced Substation
8836 Alpha) subtitles format.
8838 The filter accepts the following options:
8842 Set the filename of the subtitle file to read. It must be specified.
8845 Specify the size of the original video, the video for which the ASS file
8846 was composed. For the syntax of this option, check the
8847 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
8848 Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
8849 correctly scale the fonts if the aspect ratio has been changed.
8852 Set subtitles input character encoding. @code{subtitles} filter only. Only
8853 useful if not UTF-8.
8855 @item stream_index, si
8856 Set subtitles stream index. @code{subtitles} filter only.
8859 Override default style or script info parameters of the subtitles. It accepts a
8860 string containing ASS style format @code{KEY=VALUE} couples separated by ",".
8863 If the first key is not specified, it is assumed that the first value
8864 specifies the @option{filename}.
8866 For example, to render the file @file{sub.srt} on top of the input
8867 video, use the command:
8872 which is equivalent to:
8874 subtitles=filename=sub.srt
8877 To render the default subtitles stream from file @file{video.mkv}, use:
8882 To render the second subtitles stream from that file, use:
8884 subtitles=video.mkv:si=1
8887 To make the subtitles stream from @file{sub.srt} appear in transparent green
8888 @code{DejaVu Serif}, use:
8890 subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'
8895 Scale the input by 2x and smooth using the Super2xSaI (Scale and
8896 Interpolate) pixel art scaling algorithm.
8898 Useful for enlarging pixel art images without reducing sharpness.
8905 Apply telecine process to the video.
8907 This filter accepts the following options:
8916 The default value is @code{top}.
8920 A string of numbers representing the pulldown pattern you wish to apply.
8921 The default value is @code{23}.
8925 Some typical patterns:
8930 24p: 2332 (preferred)
8937 24p: 222222222223 ("Euro pulldown")
8943 Select the most representative frame in a given sequence of consecutive frames.
8945 The filter accepts the following options:
8949 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
8950 will pick one of them, and then handle the next batch of @var{n} frames until
8951 the end. Default is @code{100}.
8954 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
8955 value will result in a higher memory usage, so a high value is not recommended.
8957 @subsection Examples
8961 Extract one picture each 50 frames:
8967 Complete example of a thumbnail creation with @command{ffmpeg}:
8969 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
8975 Tile several successive frames together.
8977 The filter accepts the following options:
8982 Set the grid size (i.e. the number of lines and columns). For the syntax of
8983 this option, check the
8984 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
8987 Set the maximum number of frames to render in the given area. It must be less
8988 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
8989 the area will be used.
8992 Set the outer border margin in pixels.
8995 Set the inner border thickness (i.e. the number of pixels between frames). For
8996 more advanced padding options (such as having different values for the edges),
8997 refer to the pad video filter.
9000 Specify the color of the unused area. For the syntax of this option, check the
9001 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
9005 @subsection Examples
9009 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
9011 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
9013 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
9014 duplicating each output frame to accommodate the originally detected frame
9018 Display @code{5} pictures in an area of @code{3x2} frames,
9019 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
9020 mixed flat and named options:
9022 tile=3x2:nb_frames=5:padding=7:margin=2
9028 Perform various types of temporal field interlacing.
9030 Frames are counted starting from 1, so the first input frame is
9033 The filter accepts the following options:
9038 Specify the mode of the interlacing. This option can also be specified
9039 as a value alone. See below for a list of values for this option.
9041 Available values are:
9045 Move odd frames into the upper field, even into the lower field,
9046 generating a double height frame at half frame rate.
9050 Frame 1 Frame 2 Frame 3 Frame 4
9052 11111 22222 33333 44444
9053 11111 22222 33333 44444
9054 11111 22222 33333 44444
9055 11111 22222 33333 44444
9069 Only output even frames, odd frames are dropped, generating a frame with
9070 unchanged height at half frame rate.
9075 Frame 1 Frame 2 Frame 3 Frame 4
9077 11111 22222 33333 44444
9078 11111 22222 33333 44444
9079 11111 22222 33333 44444
9080 11111 22222 33333 44444
9090 Only output odd frames, even frames are dropped, generating a frame with
9091 unchanged height at half frame rate.
9096 Frame 1 Frame 2 Frame 3 Frame 4
9098 11111 22222 33333 44444
9099 11111 22222 33333 44444
9100 11111 22222 33333 44444
9101 11111 22222 33333 44444
9111 Expand each frame to full height, but pad alternate lines with black,
9112 generating a frame with double height at the same input frame rate.
9117 Frame 1 Frame 2 Frame 3 Frame 4
9119 11111 22222 33333 44444
9120 11111 22222 33333 44444
9121 11111 22222 33333 44444
9122 11111 22222 33333 44444
9125 11111 ..... 33333 .....
9126 ..... 22222 ..... 44444
9127 11111 ..... 33333 .....
9128 ..... 22222 ..... 44444
9129 11111 ..... 33333 .....
9130 ..... 22222 ..... 44444
9131 11111 ..... 33333 .....
9132 ..... 22222 ..... 44444
9136 @item interleave_top, 4
9137 Interleave the upper field from odd frames with the lower field from
9138 even frames, generating a frame with unchanged height at half frame rate.
9143 Frame 1 Frame 2 Frame 3 Frame 4
9145 11111<- 22222 33333<- 44444
9146 11111 22222<- 33333 44444<-
9147 11111<- 22222 33333<- 44444
9148 11111 22222<- 33333 44444<-
9158 @item interleave_bottom, 5
9159 Interleave the lower field from odd frames with the upper field from
9160 even frames, generating a frame with unchanged height at half frame rate.
9165 Frame 1 Frame 2 Frame 3 Frame 4
9167 11111 22222<- 33333 44444<-
9168 11111<- 22222 33333<- 44444
9169 11111 22222<- 33333 44444<-
9170 11111<- 22222 33333<- 44444
9180 @item interlacex2, 6
9181 Double frame rate with unchanged height. Frames are inserted each
9182 containing the second temporal field from the previous input frame and
9183 the first temporal field from the next input frame. This mode relies on
9184 the top_field_first flag. Useful for interlaced video displays with no
9185 field synchronisation.
9190 Frame 1 Frame 2 Frame 3 Frame 4
9192 11111 22222 33333 44444
9193 11111 22222 33333 44444
9194 11111 22222 33333 44444
9195 11111 22222 33333 44444
9198 11111 22222 22222 33333 33333 44444 44444
9199 11111 11111 22222 22222 33333 33333 44444
9200 11111 22222 22222 33333 33333 44444 44444
9201 11111 11111 22222 22222 33333 33333 44444
9207 Numeric values are deprecated but are accepted for backward
9208 compatibility reasons.
9210 Default mode is @code{merge}.
9213 Specify flags influencing the filter process.
9215 Available value for @var{flags} is:
9218 @item low_pass_filter, vlfp
9219 Enable vertical low-pass filtering in the filter.
9220 Vertical low-pass filtering is required when creating an interlaced
9221 destination from a progressive source which contains high-frequency
9222 vertical detail. Filtering will reduce interlace 'twitter' and Moire
9225 Vertical low-pass filtering can only be enabled for @option{mode}
9226 @var{interleave_top} and @var{interleave_bottom}.
9233 Transpose rows with columns in the input video and optionally flip it.
9235 It accepts the following parameters:
9240 Specify the transposition direction.
9242 Can assume the following values:
9244 @item 0, 4, cclock_flip
9245 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
9253 Rotate by 90 degrees clockwise, that is:
9261 Rotate by 90 degrees counterclockwise, that is:
9268 @item 3, 7, clock_flip
9269 Rotate by 90 degrees clockwise and vertically flip, that is:
9277 For values between 4-7, the transposition is only done if the input
9278 video geometry is portrait and not landscape. These values are
9279 deprecated, the @code{passthrough} option should be used instead.
9281 Numerical values are deprecated, and should be dropped in favor of
9285 Do not apply the transposition if the input geometry matches the one
9286 specified by the specified value. It accepts the following values:
9289 Always apply transposition.
9291 Preserve portrait geometry (when @var{height} >= @var{width}).
9293 Preserve landscape geometry (when @var{width} >= @var{height}).
9296 Default value is @code{none}.
9299 For example to rotate by 90 degrees clockwise and preserve portrait
9302 transpose=dir=1:passthrough=portrait
9305 The command above can also be specified as:
9307 transpose=1:portrait
9311 Trim the input so that the output contains one continuous subpart of the input.
9313 It accepts the following parameters:
9316 Specify the time of the start of the kept section, i.e. the frame with the
9317 timestamp @var{start} will be the first frame in the output.
9320 Specify the time of the first frame that will be dropped, i.e. the frame
9321 immediately preceding the one with the timestamp @var{end} will be the last
9322 frame in the output.
9325 This is the same as @var{start}, except this option sets the start timestamp
9326 in timebase units instead of seconds.
9329 This is the same as @var{end}, except this option sets the end timestamp
9330 in timebase units instead of seconds.
9333 The maximum duration of the output in seconds.
9336 The number of the first frame that should be passed to the output.
9339 The number of the first frame that should be dropped.
9342 @option{start}, @option{end}, and @option{duration} are expressed as time
9343 duration specifications; see
9344 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
9345 for the accepted syntax.
9347 Note that the first two sets of the start/end options and the @option{duration}
9348 option look at the frame timestamp, while the _frame variants simply count the
9349 frames that pass through the filter. Also note that this filter does not modify
9350 the timestamps. If you wish for the output timestamps to start at zero, insert a
9351 setpts filter after the trim filter.
9353 If multiple start or end options are set, this filter tries to be greedy and
9354 keep all the frames that match at least one of the specified constraints. To keep
9355 only the part that matches all the constraints at once, chain multiple trim
9358 The defaults are such that all the input is kept. So it is possible to set e.g.
9359 just the end values to keep everything before the specified time.
9364 Drop everything except the second minute of input:
9366 ffmpeg -i INPUT -vf trim=60:120
9370 Keep only the first second:
9372 ffmpeg -i INPUT -vf trim=duration=1
9381 Sharpen or blur the input video.
9383 It accepts the following parameters:
9386 @item luma_msize_x, lx
9387 Set the luma matrix horizontal size. It must be an odd integer between
9388 3 and 63. The default value is 5.
9390 @item luma_msize_y, ly
9391 Set the luma matrix vertical size. It must be an odd integer between 3
9392 and 63. The default value is 5.
9394 @item luma_amount, la
9395 Set the luma effect strength. It must be a floating point number, reasonable
9396 values lay between -1.5 and 1.5.
9398 Negative values will blur the input video, while positive values will
9399 sharpen it, a value of zero will disable the effect.
9401 Default value is 1.0.
9403 @item chroma_msize_x, cx
9404 Set the chroma matrix horizontal size. It must be an odd integer
9405 between 3 and 63. The default value is 5.
9407 @item chroma_msize_y, cy
9408 Set the chroma matrix vertical size. It must be an odd integer
9409 between 3 and 63. The default value is 5.
9411 @item chroma_amount, ca
9412 Set the chroma effect strength. It must be a floating point number, reasonable
9413 values lay between -1.5 and 1.5.
9415 Negative values will blur the input video, while positive values will
9416 sharpen it, a value of zero will disable the effect.
9418 Default value is 0.0.
9421 If set to 1, specify using OpenCL capabilities, only available if
9422 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
9426 All parameters are optional and default to the equivalent of the
9427 string '5:5:1.0:5:5:0.0'.
9429 @subsection Examples
9433 Apply strong luma sharpen effect:
9435 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
9439 Apply a strong blur of both luma and chroma parameters:
9441 unsharp=7:7:-2:7:7:-2
9447 Apply ultra slow/simple postprocessing filter that compresses and decompresses
9448 the image at several (or - in the case of @option{quality} level @code{8} - all)
9449 shifts and average the results.
9451 The way this differs from the behavior of spp is that uspp actually encodes &
9452 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
9453 DCT similar to MJPEG.
9455 The filter accepts the following options:
9459 Set quality. This option defines the number of levels for averaging. It accepts
9460 an integer in the range 0-8. If set to @code{0}, the filter will have no
9461 effect. A value of @code{8} means the higher quality. For each increment of
9462 that value the speed drops by a factor of approximately 2. Default value is
9466 Force a constant quantization parameter. If not set, the filter will use the QP
9467 from the video stream (if available).
9470 @anchor{vidstabdetect}
9471 @section vidstabdetect
9473 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
9474 @ref{vidstabtransform} for pass 2.
9476 This filter generates a file with relative translation and rotation
9477 transform information about subsequent frames, which is then used by
9478 the @ref{vidstabtransform} filter.
9480 To enable compilation of this filter you need to configure FFmpeg with
9481 @code{--enable-libvidstab}.
9483 This filter accepts the following options:
9487 Set the path to the file used to write the transforms information.
9488 Default value is @file{transforms.trf}.
9491 Set how shaky the video is and how quick the camera is. It accepts an
9492 integer in the range 1-10, a value of 1 means little shakiness, a
9493 value of 10 means strong shakiness. Default value is 5.
9496 Set the accuracy of the detection process. It must be a value in the
9497 range 1-15. A value of 1 means low accuracy, a value of 15 means high
9498 accuracy. Default value is 15.
9501 Set stepsize of the search process. The region around minimum is
9502 scanned with 1 pixel resolution. Default value is 6.
9505 Set minimum contrast. Below this value a local measurement field is
9506 discarded. Must be a floating point value in the range 0-1. Default
9510 Set reference frame number for tripod mode.
9512 If enabled, the motion of the frames is compared to a reference frame
9513 in the filtered stream, identified by the specified number. The idea
9514 is to compensate all movements in a more-or-less static scene and keep
9515 the camera view absolutely still.
9517 If set to 0, it is disabled. The frames are counted starting from 1.
9520 Show fields and transforms in the resulting frames. It accepts an
9521 integer in the range 0-2. Default value is 0, which disables any
9525 @subsection Examples
9535 Analyze strongly shaky movie and put the results in file
9536 @file{mytransforms.trf}:
9538 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
9542 Visualize the result of internal transformations in the resulting
9545 vidstabdetect=show=1
9549 Analyze a video with medium shakiness using @command{ffmpeg}:
9551 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
9555 @anchor{vidstabtransform}
9556 @section vidstabtransform
9558 Video stabilization/deshaking: pass 2 of 2,
9559 see @ref{vidstabdetect} for pass 1.
9561 Read a file with transform information for each frame and
9562 apply/compensate them. Together with the @ref{vidstabdetect}
9563 filter this can be used to deshake videos. See also
9564 @url{http://public.hronopik.de/vid.stab}. It is important to also use
9565 the @ref{unsharp} filter, see below.
9567 To enable compilation of this filter you need to configure FFmpeg with
9568 @code{--enable-libvidstab}.
9574 Set path to the file used to read the transforms. Default value is
9575 @file{transforms.trf}.
9578 Set the number of frames (value*2 + 1) used for lowpass filtering the
9579 camera movements. Default value is 10.
9581 For example a number of 10 means that 21 frames are used (10 in the
9582 past and 10 in the future) to smoothen the motion in the video. A
9583 larger value leads to a smoother video, but limits the acceleration of
9584 the camera (pan/tilt movements). 0 is a special case where a static
9585 camera is simulated.
9588 Set the camera path optimization algorithm.
9590 Accepted values are:
9593 gaussian kernel low-pass filter on camera motion (default)
9595 averaging on transformations
9599 Set maximal number of pixels to translate frames. Default value is -1,
9603 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
9604 value is -1, meaning no limit.
9607 Specify how to deal with borders that may be visible due to movement
9610 Available values are:
9613 keep image information from previous frame (default)
9615 fill the border black
9619 Invert transforms if set to 1. Default value is 0.
9622 Consider transforms as relative to previous frame if set to 1,
9623 absolute if set to 0. Default value is 0.
9626 Set percentage to zoom. A positive value will result in a zoom-in
9627 effect, a negative value in a zoom-out effect. Default value is 0 (no
9631 Set optimal zooming to avoid borders.
9633 Accepted values are:
9638 optimal static zoom value is determined (only very strong movements
9639 will lead to visible borders) (default)
9641 optimal adaptive zoom value is determined (no borders will be
9642 visible), see @option{zoomspeed}
9645 Note that the value given at zoom is added to the one calculated here.
9648 Set percent to zoom maximally each frame (enabled when
9649 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
9653 Specify type of interpolation.
9655 Available values are:
9660 linear only horizontal
9662 linear in both directions (default)
9664 cubic in both directions (slow)
9668 Enable virtual tripod mode if set to 1, which is equivalent to
9669 @code{relative=0:smoothing=0}. Default value is 0.
9671 Use also @code{tripod} option of @ref{vidstabdetect}.
9674 Increase log verbosity if set to 1. Also the detected global motions
9675 are written to the temporary file @file{global_motions.trf}. Default
9679 @subsection Examples
9683 Use @command{ffmpeg} for a typical stabilization with default values:
9685 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
9688 Note the use of the @ref{unsharp} filter which is always recommended.
9691 Zoom in a bit more and load transform data from a given file:
9693 vidstabtransform=zoom=5:input="mytransforms.trf"
9697 Smoothen the video even more:
9699 vidstabtransform=smoothing=30
9705 Flip the input video vertically.
9707 For example, to vertically flip a video with @command{ffmpeg}:
9709 ffmpeg -i in.avi -vf "vflip" out.avi
9715 Make or reverse a natural vignetting effect.
9717 The filter accepts the following options:
9721 Set lens angle expression as a number of radians.
9723 The value is clipped in the @code{[0,PI/2]} range.
9725 Default value: @code{"PI/5"}
9729 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
9733 Set forward/backward mode.
9735 Available modes are:
9738 The larger the distance from the central point, the darker the image becomes.
9741 The larger the distance from the central point, the brighter the image becomes.
9742 This can be used to reverse a vignette effect, though there is no automatic
9743 detection to extract the lens @option{angle} and other settings (yet). It can
9744 also be used to create a burning effect.
9747 Default value is @samp{forward}.
9750 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
9752 It accepts the following values:
9755 Evaluate expressions only once during the filter initialization.
9758 Evaluate expressions for each incoming frame. This is way slower than the
9759 @samp{init} mode since it requires all the scalers to be re-computed, but it
9760 allows advanced dynamic expressions.
9763 Default value is @samp{init}.
9766 Set dithering to reduce the circular banding effects. Default is @code{1}
9770 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
9771 Setting this value to the SAR of the input will make a rectangular vignetting
9772 following the dimensions of the video.
9774 Default is @code{1/1}.
9777 @subsection Expressions
9779 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
9780 following parameters.
9785 input width and height
9788 the number of input frame, starting from 0
9791 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
9792 @var{TB} units, NAN if undefined
9795 frame rate of the input video, NAN if the input frame rate is unknown
9798 the PTS (Presentation TimeStamp) of the filtered video frame,
9799 expressed in seconds, NAN if undefined
9802 time base of the input video
9806 @subsection Examples
9810 Apply simple strong vignetting effect:
9816 Make a flickering vignetting:
9818 vignette='PI/4+random(1)*PI/50':eval=frame
9825 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
9826 Deinterlacing Filter").
9828 Based on the process described by Martin Weston for BBC R&D, and
9829 implemented based on the de-interlace algorithm written by Jim
9830 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
9831 uses filter coefficients calculated by BBC R&D.
9833 There are two sets of filter coefficients, so called "simple":
9834 and "complex". Which set of filter coefficients is used can
9835 be set by passing an optional parameter:
9839 Set the interlacing filter coefficients. Accepts one of the following values:
9843 Simple filter coefficient set.
9845 More-complex filter coefficient set.
9847 Default value is @samp{complex}.
9850 Specify which frames to deinterlace. Accept one of the following values:
9854 Deinterlace all frames,
9856 Only deinterlace frames marked as interlaced.
9859 Default value is @samp{all}.
9863 Apply the xBR high-quality magnification filter which is designed for pixel
9864 art. It follows a set of edge-detection rules, see
9865 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
9867 It accepts the following option:
9871 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
9872 @code{3xBR} and @code{4} for @code{4xBR}.
9873 Default is @code{3}.
9879 Deinterlace the input video ("yadif" means "yet another deinterlacing
9882 It accepts the following parameters:
9888 The interlacing mode to adopt. It accepts one of the following values:
9892 Output one frame for each frame.
9894 Output one frame for each field.
9895 @item 2, send_frame_nospatial
9896 Like @code{send_frame}, but it skips the spatial interlacing check.
9897 @item 3, send_field_nospatial
9898 Like @code{send_field}, but it skips the spatial interlacing check.
9901 The default value is @code{send_frame}.
9904 The picture field parity assumed for the input interlaced video. It accepts one
9905 of the following values:
9909 Assume the top field is first.
9911 Assume the bottom field is first.
9913 Enable automatic detection of field parity.
9916 The default value is @code{auto}.
9917 If the interlacing is unknown or the decoder does not export this information,
9918 top field first will be assumed.
9921 Specify which frames to deinterlace. Accept one of the following
9926 Deinterlace all frames.
9928 Only deinterlace frames marked as interlaced.
9931 The default value is @code{all}.
9936 Apply Zoom & Pan effect.
9938 This filter accepts the following options:
9942 Set the zoom expression. Default is 1.
9946 Set the x and y expression. Default is 0.
9949 Set the duration expression in number of frames.
9950 This sets for how many number of frames effect will last for
9954 Set the output image size, default is 'hd720'.
9957 Each expression can contain the following constants:
9980 Last calculated 'x' and 'y' position from 'x' and 'y' expression
9981 for current input frame.
9985 'x' and 'y' of last output frame of previous input frame or 0 when there was
9986 not yet such frame (first input frame).
9989 Last calculated zoom from 'z' expression for current input frame.
9992 Last calculated zoom of last output frame of previous input frame.
9995 Number of output frames for current input frame. Calculated from 'd' expression
9996 for each input frame.
9999 number of output frames created for previous input frame
10002 Rational number: input width / input height
10005 sample aspect ratio
10008 display aspect ratio
10012 @subsection Examples
10016 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
10018 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
10022 @c man end VIDEO FILTERS
10024 @chapter Video Sources
10025 @c man begin VIDEO SOURCES
10027 Below is a description of the currently available video sources.
10031 Buffer video frames, and make them available to the filter chain.
10033 This source is mainly intended for a programmatic use, in particular
10034 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
10036 It accepts the following parameters:
10041 Specify the size (width and height) of the buffered video frames. For the
10042 syntax of this option, check the
10043 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10046 The input video width.
10049 The input video height.
10052 A string representing the pixel format of the buffered video frames.
10053 It may be a number corresponding to a pixel format, or a pixel format
10057 Specify the timebase assumed by the timestamps of the buffered frames.
10060 Specify the frame rate expected for the video stream.
10062 @item pixel_aspect, sar
10063 The sample (pixel) aspect ratio of the input video.
10066 Specify the optional parameters to be used for the scale filter which
10067 is automatically inserted when an input change is detected in the
10068 input size or format.
10073 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
10076 will instruct the source to accept video frames with size 320x240 and
10077 with format "yuv410p", assuming 1/24 as the timestamps timebase and
10078 square pixels (1:1 sample aspect ratio).
10079 Since the pixel format with name "yuv410p" corresponds to the number 6
10080 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
10081 this example corresponds to:
10083 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
10086 Alternatively, the options can be specified as a flat string, but this
10087 syntax is deprecated:
10089 @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}]
10093 Create a pattern generated by an elementary cellular automaton.
10095 The initial state of the cellular automaton can be defined through the
10096 @option{filename}, and @option{pattern} options. If such options are
10097 not specified an initial state is created randomly.
10099 At each new frame a new row in the video is filled with the result of
10100 the cellular automaton next generation. The behavior when the whole
10101 frame is filled is defined by the @option{scroll} option.
10103 This source accepts the following options:
10107 Read the initial cellular automaton state, i.e. the starting row, from
10108 the specified file.
10109 In the file, each non-whitespace character is considered an alive
10110 cell, a newline will terminate the row, and further characters in the
10111 file will be ignored.
10114 Read the initial cellular automaton state, i.e. the starting row, from
10115 the specified string.
10117 Each non-whitespace character in the string is considered an alive
10118 cell, a newline will terminate the row, and further characters in the
10119 string will be ignored.
10122 Set the video rate, that is the number of frames generated per second.
10125 @item random_fill_ratio, ratio
10126 Set the random fill ratio for the initial cellular automaton row. It
10127 is a floating point number value ranging from 0 to 1, defaults to
10130 This option is ignored when a file or a pattern is specified.
10132 @item random_seed, seed
10133 Set the seed for filling randomly the initial row, must be an integer
10134 included between 0 and UINT32_MAX. If not specified, or if explicitly
10135 set to -1, the filter will try to use a good random seed on a best
10139 Set the cellular automaton rule, it is a number ranging from 0 to 255.
10140 Default value is 110.
10143 Set the size of the output video. For the syntax of this option, check the
10144 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10146 If @option{filename} or @option{pattern} is specified, the size is set
10147 by default to the width of the specified initial state row, and the
10148 height is set to @var{width} * PHI.
10150 If @option{size} is set, it must contain the width of the specified
10151 pattern string, and the specified pattern will be centered in the
10154 If a filename or a pattern string is not specified, the size value
10155 defaults to "320x518" (used for a randomly generated initial state).
10158 If set to 1, scroll the output upward when all the rows in the output
10159 have been already filled. If set to 0, the new generated row will be
10160 written over the top row just after the bottom row is filled.
10163 @item start_full, full
10164 If set to 1, completely fill the output with generated rows before
10165 outputting the first frame.
10166 This is the default behavior, for disabling set the value to 0.
10169 If set to 1, stitch the left and right row edges together.
10170 This is the default behavior, for disabling set the value to 0.
10173 @subsection Examples
10177 Read the initial state from @file{pattern}, and specify an output of
10180 cellauto=f=pattern:s=200x400
10184 Generate a random initial row with a width of 200 cells, with a fill
10187 cellauto=ratio=2/3:s=200x200
10191 Create a pattern generated by rule 18 starting by a single alive cell
10192 centered on an initial row with width 100:
10194 cellauto=p=@@:s=100x400:full=0:rule=18
10198 Specify a more elaborated initial pattern:
10200 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
10205 @section mandelbrot
10207 Generate a Mandelbrot set fractal, and progressively zoom towards the
10208 point specified with @var{start_x} and @var{start_y}.
10210 This source accepts the following options:
10215 Set the terminal pts value. Default value is 400.
10218 Set the terminal scale value.
10219 Must be a floating point value. Default value is 0.3.
10222 Set the inner coloring mode, that is the algorithm used to draw the
10223 Mandelbrot fractal internal region.
10225 It shall assume one of the following values:
10230 Show time until convergence.
10232 Set color based on point closest to the origin of the iterations.
10237 Default value is @var{mincol}.
10240 Set the bailout value. Default value is 10.0.
10243 Set the maximum of iterations performed by the rendering
10244 algorithm. Default value is 7189.
10247 Set outer coloring mode.
10248 It shall assume one of following values:
10250 @item iteration_count
10251 Set iteration cound mode.
10252 @item normalized_iteration_count
10253 set normalized iteration count mode.
10255 Default value is @var{normalized_iteration_count}.
10258 Set frame rate, expressed as number of frames per second. Default
10262 Set frame size. For the syntax of this option, check the "Video
10263 size" section in the ffmpeg-utils manual. Default value is "640x480".
10266 Set the initial scale value. Default value is 3.0.
10269 Set the initial x position. Must be a floating point value between
10270 -100 and 100. Default value is -0.743643887037158704752191506114774.
10273 Set the initial y position. Must be a floating point value between
10274 -100 and 100. Default value is -0.131825904205311970493132056385139.
10279 Generate various test patterns, as generated by the MPlayer test filter.
10281 The size of the generated video is fixed, and is 256x256.
10282 This source is useful in particular for testing encoding features.
10284 This source accepts the following options:
10289 Specify the frame rate of the sourced video, as the number of frames
10290 generated per second. It has to be a string in the format
10291 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
10292 number or a valid video frame rate abbreviation. The default value is
10296 Set the duration of the sourced video. See
10297 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
10298 for the accepted syntax.
10300 If not specified, or the expressed duration is negative, the video is
10301 supposed to be generated forever.
10305 Set the number or the name of the test to perform. Supported tests are:
10321 Default value is "all", which will cycle through the list of all tests.
10326 mptestsrc=t=dc_luma
10329 will generate a "dc_luma" test pattern.
10331 @section frei0r_src
10333 Provide a frei0r source.
10335 To enable compilation of this filter you need to install the frei0r
10336 header and configure FFmpeg with @code{--enable-frei0r}.
10338 This source accepts the following parameters:
10343 The size of the video to generate. For the syntax of this option, check the
10344 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10347 The framerate of the generated video. It may be a string of the form
10348 @var{num}/@var{den} or a frame rate abbreviation.
10351 The name to the frei0r source to load. For more information regarding frei0r and
10352 how to set the parameters, read the @ref{frei0r} section in the video filters
10355 @item filter_params
10356 A '|'-separated list of parameters to pass to the frei0r source.
10360 For example, to generate a frei0r partik0l source with size 200x200
10361 and frame rate 10 which is overlaid on the overlay filter main input:
10363 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
10368 Generate a life pattern.
10370 This source is based on a generalization of John Conway's life game.
10372 The sourced input represents a life grid, each pixel represents a cell
10373 which can be in one of two possible states, alive or dead. Every cell
10374 interacts with its eight neighbours, which are the cells that are
10375 horizontally, vertically, or diagonally adjacent.
10377 At each interaction the grid evolves according to the adopted rule,
10378 which specifies the number of neighbor alive cells which will make a
10379 cell stay alive or born. The @option{rule} option allows one to specify
10382 This source accepts the following options:
10386 Set the file from which to read the initial grid state. In the file,
10387 each non-whitespace character is considered an alive cell, and newline
10388 is used to delimit the end of each row.
10390 If this option is not specified, the initial grid is generated
10394 Set the video rate, that is the number of frames generated per second.
10397 @item random_fill_ratio, ratio
10398 Set the random fill ratio for the initial random grid. It is a
10399 floating point number value ranging from 0 to 1, defaults to 1/PHI.
10400 It is ignored when a file is specified.
10402 @item random_seed, seed
10403 Set the seed for filling the initial random grid, must be an integer
10404 included between 0 and UINT32_MAX. If not specified, or if explicitly
10405 set to -1, the filter will try to use a good random seed on a best
10411 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
10412 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
10413 @var{NS} specifies the number of alive neighbor cells which make a
10414 live cell stay alive, and @var{NB} the number of alive neighbor cells
10415 which make a dead cell to become alive (i.e. to "born").
10416 "s" and "b" can be used in place of "S" and "B", respectively.
10418 Alternatively a rule can be specified by an 18-bits integer. The 9
10419 high order bits are used to encode the next cell state if it is alive
10420 for each number of neighbor alive cells, the low order bits specify
10421 the rule for "borning" new cells. Higher order bits encode for an
10422 higher number of neighbor cells.
10423 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
10424 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
10426 Default value is "S23/B3", which is the original Conway's game of life
10427 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
10428 cells, and will born a new cell if there are three alive cells around
10432 Set the size of the output video. For the syntax of this option, check the
10433 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10435 If @option{filename} is specified, the size is set by default to the
10436 same size of the input file. If @option{size} is set, it must contain
10437 the size specified in the input file, and the initial grid defined in
10438 that file is centered in the larger resulting area.
10440 If a filename is not specified, the size value defaults to "320x240"
10441 (used for a randomly generated initial grid).
10444 If set to 1, stitch the left and right grid edges together, and the
10445 top and bottom edges also. Defaults to 1.
10448 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
10449 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
10450 value from 0 to 255.
10453 Set the color of living (or new born) cells.
10456 Set the color of dead cells. If @option{mold} is set, this is the first color
10457 used to represent a dead cell.
10460 Set mold color, for definitely dead and moldy cells.
10462 For the syntax of these 3 color options, check the "Color" section in the
10463 ffmpeg-utils manual.
10466 @subsection Examples
10470 Read a grid from @file{pattern}, and center it on a grid of size
10473 life=f=pattern:s=300x300
10477 Generate a random grid of size 200x200, with a fill ratio of 2/3:
10479 life=ratio=2/3:s=200x200
10483 Specify a custom rule for evolving a randomly generated grid:
10489 Full example with slow death effect (mold) using @command{ffplay}:
10491 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
10496 @anchor{haldclutsrc}
10498 @anchor{rgbtestsrc}
10500 @anchor{smptehdbars}
10502 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
10504 The @code{color} source provides an uniformly colored input.
10506 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
10507 @ref{haldclut} filter.
10509 The @code{nullsrc} source returns unprocessed video frames. It is
10510 mainly useful to be employed in analysis / debugging tools, or as the
10511 source for filters which ignore the input data.
10513 The @code{rgbtestsrc} source generates an RGB test pattern useful for
10514 detecting RGB vs BGR issues. You should see a red, green and blue
10515 stripe from top to bottom.
10517 The @code{smptebars} source generates a color bars pattern, based on
10518 the SMPTE Engineering Guideline EG 1-1990.
10520 The @code{smptehdbars} source generates a color bars pattern, based on
10521 the SMPTE RP 219-2002.
10523 The @code{testsrc} source generates a test video pattern, showing a
10524 color pattern, a scrolling gradient and a timestamp. This is mainly
10525 intended for testing purposes.
10527 The sources accept the following parameters:
10532 Specify the color of the source, only available in the @code{color}
10533 source. For the syntax of this option, check the "Color" section in the
10534 ffmpeg-utils manual.
10537 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
10538 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
10539 pixels to be used as identity matrix for 3D lookup tables. Each component is
10540 coded on a @code{1/(N*N)} scale.
10543 Specify the size of the sourced video. For the syntax of this option, check the
10544 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10545 The default value is @code{320x240}.
10547 This option is not available with the @code{haldclutsrc} filter.
10550 Specify the frame rate of the sourced video, as the number of frames
10551 generated per second. It has to be a string in the format
10552 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
10553 number or a valid video frame rate abbreviation. The default value is
10557 Set the sample aspect ratio of the sourced video.
10560 Set the duration of the sourced video. See
10561 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
10562 for the accepted syntax.
10564 If not specified, or the expressed duration is negative, the video is
10565 supposed to be generated forever.
10568 Set the number of decimals to show in the timestamp, only available in the
10569 @code{testsrc} source.
10571 The displayed timestamp value will correspond to the original
10572 timestamp value multiplied by the power of 10 of the specified
10573 value. Default value is 0.
10576 For example the following:
10578 testsrc=duration=5.3:size=qcif:rate=10
10581 will generate a video with a duration of 5.3 seconds, with size
10582 176x144 and a frame rate of 10 frames per second.
10584 The following graph description will generate a red source
10585 with an opacity of 0.2, with size "qcif" and a frame rate of 10
10588 color=c=red@@0.2:s=qcif:r=10
10591 If the input content is to be ignored, @code{nullsrc} can be used. The
10592 following command generates noise in the luminance plane by employing
10593 the @code{geq} filter:
10595 nullsrc=s=256x256, geq=random(1)*255:128:128
10598 @subsection Commands
10600 The @code{color} source supports the following commands:
10604 Set the color of the created image. Accepts the same syntax of the
10605 corresponding @option{color} option.
10608 @c man end VIDEO SOURCES
10610 @chapter Video Sinks
10611 @c man begin VIDEO SINKS
10613 Below is a description of the currently available video sinks.
10615 @section buffersink
10617 Buffer video frames, and make them available to the end of the filter
10620 This sink is mainly intended for programmatic use, in particular
10621 through the interface defined in @file{libavfilter/buffersink.h}
10622 or the options system.
10624 It accepts a pointer to an AVBufferSinkContext structure, which
10625 defines the incoming buffers' formats, to be passed as the opaque
10626 parameter to @code{avfilter_init_filter} for initialization.
10630 Null video sink: do absolutely nothing with the input video. It is
10631 mainly useful as a template and for use in analysis / debugging
10634 @c man end VIDEO SINKS
10636 @chapter Multimedia Filters
10637 @c man begin MULTIMEDIA FILTERS
10639 Below is a description of the currently available multimedia filters.
10641 @section avectorscope
10643 Convert input audio to a video output, representing the audio vector
10646 The filter is used to measure the difference between channels of stereo
10647 audio stream. A monoaural signal, consisting of identical left and right
10648 signal, results in straight vertical line. Any stereo separation is visible
10649 as a deviation from this line, creating a Lissajous figure.
10650 If the straight (or deviation from it) but horizontal line appears this
10651 indicates that the left and right channels are out of phase.
10653 The filter accepts the following options:
10657 Set the vectorscope mode.
10659 Available values are:
10662 Lissajous rotated by 45 degrees.
10665 Same as above but not rotated.
10668 Default value is @samp{lissajous}.
10671 Set the video size for the output. For the syntax of this option, check the
10672 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10673 Default value is @code{400x400}.
10676 Set the output frame rate. Default value is @code{25}.
10681 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
10682 Allowed range is @code{[0, 255]}.
10687 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
10688 Allowed range is @code{[0, 255]}.
10691 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
10694 @subsection Examples
10698 Complete example using @command{ffplay}:
10700 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10701 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
10707 Concatenate audio and video streams, joining them together one after the
10710 The filter works on segments of synchronized video and audio streams. All
10711 segments must have the same number of streams of each type, and that will
10712 also be the number of streams at output.
10714 The filter accepts the following options:
10719 Set the number of segments. Default is 2.
10722 Set the number of output video streams, that is also the number of video
10723 streams in each segment. Default is 1.
10726 Set the number of output audio streams, that is also the number of audio
10727 streams in each segment. Default is 0.
10730 Activate unsafe mode: do not fail if segments have a different format.
10734 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
10735 @var{a} audio outputs.
10737 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
10738 segment, in the same order as the outputs, then the inputs for the second
10741 Related streams do not always have exactly the same duration, for various
10742 reasons including codec frame size or sloppy authoring. For that reason,
10743 related synchronized streams (e.g. a video and its audio track) should be
10744 concatenated at once. The concat filter will use the duration of the longest
10745 stream in each segment (except the last one), and if necessary pad shorter
10746 audio streams with silence.
10748 For this filter to work correctly, all segments must start at timestamp 0.
10750 All corresponding streams must have the same parameters in all segments; the
10751 filtering system will automatically select a common pixel format for video
10752 streams, and a common sample format, sample rate and channel layout for
10753 audio streams, but other settings, such as resolution, must be converted
10754 explicitly by the user.
10756 Different frame rates are acceptable but will result in variable frame rate
10757 at output; be sure to configure the output file to handle it.
10759 @subsection Examples
10763 Concatenate an opening, an episode and an ending, all in bilingual version
10764 (video in stream 0, audio in streams 1 and 2):
10766 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
10767 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
10768 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
10769 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
10773 Concatenate two parts, handling audio and video separately, using the
10774 (a)movie sources, and adjusting the resolution:
10776 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
10777 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
10778 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
10780 Note that a desync will happen at the stitch if the audio and video streams
10781 do not have exactly the same duration in the first file.
10787 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
10788 it unchanged. By default, it logs a message at a frequency of 10Hz with the
10789 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
10790 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
10792 The filter also has a video output (see the @var{video} option) with a real
10793 time graph to observe the loudness evolution. The graphic contains the logged
10794 message mentioned above, so it is not printed anymore when this option is set,
10795 unless the verbose logging is set. The main graphing area contains the
10796 short-term loudness (3 seconds of analysis), and the gauge on the right is for
10797 the momentary loudness (400 milliseconds).
10799 More information about the Loudness Recommendation EBU R128 on
10800 @url{http://tech.ebu.ch/loudness}.
10802 The filter accepts the following options:
10807 Activate the video output. The audio stream is passed unchanged whether this
10808 option is set or no. The video stream will be the first output stream if
10809 activated. Default is @code{0}.
10812 Set the video size. This option is for video only. For the syntax of this
10814 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10815 Default and minimum resolution is @code{640x480}.
10818 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
10819 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
10820 other integer value between this range is allowed.
10823 Set metadata injection. If set to @code{1}, the audio input will be segmented
10824 into 100ms output frames, each of them containing various loudness information
10825 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
10827 Default is @code{0}.
10830 Force the frame logging level.
10832 Available values are:
10835 information logging level
10837 verbose logging level
10840 By default, the logging level is set to @var{info}. If the @option{video} or
10841 the @option{metadata} options are set, it switches to @var{verbose}.
10846 Available modes can be cumulated (the option is a @code{flag} type). Possible
10850 Disable any peak mode (default).
10852 Enable sample-peak mode.
10854 Simple peak mode looking for the higher sample value. It logs a message
10855 for sample-peak (identified by @code{SPK}).
10857 Enable true-peak mode.
10859 If enabled, the peak lookup is done on an over-sampled version of the input
10860 stream for better peak accuracy. It logs a message for true-peak.
10861 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
10862 This mode requires a build with @code{libswresample}.
10867 @subsection Examples
10871 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
10873 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
10877 Run an analysis with @command{ffmpeg}:
10879 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
10883 @section interleave, ainterleave
10885 Temporally interleave frames from several inputs.
10887 @code{interleave} works with video inputs, @code{ainterleave} with audio.
10889 These filters read frames from several inputs and send the oldest
10890 queued frame to the output.
10892 Input streams must have a well defined, monotonically increasing frame
10895 In order to submit one frame to output, these filters need to enqueue
10896 at least one frame for each input, so they cannot work in case one
10897 input is not yet terminated and will not receive incoming frames.
10899 For example consider the case when one input is a @code{select} filter
10900 which always drop input frames. The @code{interleave} filter will keep
10901 reading from that input, but it will never be able to send new frames
10902 to output until the input will send an end-of-stream signal.
10904 Also, depending on inputs synchronization, the filters will drop
10905 frames in case one input receives more frames than the other ones, and
10906 the queue is already filled.
10908 These filters accept the following options:
10912 Set the number of different inputs, it is 2 by default.
10915 @subsection Examples
10919 Interleave frames belonging to different streams using @command{ffmpeg}:
10921 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
10925 Add flickering blur effect:
10927 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
10931 @section perms, aperms
10933 Set read/write permissions for the output frames.
10935 These filters are mainly aimed at developers to test direct path in the
10936 following filter in the filtergraph.
10938 The filters accept the following options:
10942 Select the permissions mode.
10944 It accepts the following values:
10947 Do nothing. This is the default.
10949 Set all the output frames read-only.
10951 Set all the output frames directly writable.
10953 Make the frame read-only if writable, and writable if read-only.
10955 Set each output frame read-only or writable randomly.
10959 Set the seed for the @var{random} mode, must be an integer included between
10960 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
10961 @code{-1}, the filter will try to use a good random seed on a best effort
10965 Note: in case of auto-inserted filter between the permission filter and the
10966 following one, the permission might not be received as expected in that
10967 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
10968 perms/aperms filter can avoid this problem.
10970 @section select, aselect
10972 Select frames to pass in output.
10974 This filter accepts the following options:
10979 Set expression, which is evaluated for each input frame.
10981 If the expression is evaluated to zero, the frame is discarded.
10983 If the evaluation result is negative or NaN, the frame is sent to the
10984 first output; otherwise it is sent to the output with index
10985 @code{ceil(val)-1}, assuming that the input index starts from 0.
10987 For example a value of @code{1.2} corresponds to the output with index
10988 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
10991 Set the number of outputs. The output to which to send the selected
10992 frame is based on the result of the evaluation. Default value is 1.
10995 The expression can contain the following constants:
10999 The (sequential) number of the filtered frame, starting from 0.
11002 The (sequential) number of the selected frame, starting from 0.
11004 @item prev_selected_n
11005 The sequential number of the last selected frame. It's NAN if undefined.
11008 The timebase of the input timestamps.
11011 The PTS (Presentation TimeStamp) of the filtered video frame,
11012 expressed in @var{TB} units. It's NAN if undefined.
11015 The PTS of the filtered video frame,
11016 expressed in seconds. It's NAN if undefined.
11019 The PTS of the previously filtered video frame. It's NAN if undefined.
11021 @item prev_selected_pts
11022 The PTS of the last previously filtered video frame. It's NAN if undefined.
11024 @item prev_selected_t
11025 The PTS of the last previously selected video frame. It's NAN if undefined.
11028 The PTS of the first video frame in the video. It's NAN if undefined.
11031 The time of the first video frame in the video. It's NAN if undefined.
11033 @item pict_type @emph{(video only)}
11034 The type of the filtered frame. It can assume one of the following
11046 @item interlace_type @emph{(video only)}
11047 The frame interlace type. It can assume one of the following values:
11050 The frame is progressive (not interlaced).
11052 The frame is top-field-first.
11054 The frame is bottom-field-first.
11057 @item consumed_sample_n @emph{(audio only)}
11058 the number of selected samples before the current frame
11060 @item samples_n @emph{(audio only)}
11061 the number of samples in the current frame
11063 @item sample_rate @emph{(audio only)}
11064 the input sample rate
11067 This is 1 if the filtered frame is a key-frame, 0 otherwise.
11070 the position in the file of the filtered frame, -1 if the information
11071 is not available (e.g. for synthetic video)
11073 @item scene @emph{(video only)}
11074 value between 0 and 1 to indicate a new scene; a low value reflects a low
11075 probability for the current frame to introduce a new scene, while a higher
11076 value means the current frame is more likely to be one (see the example below)
11080 The default value of the select expression is "1".
11082 @subsection Examples
11086 Select all frames in input:
11091 The example above is the same as:
11103 Select only I-frames:
11105 select='eq(pict_type\,I)'
11109 Select one frame every 100:
11111 select='not(mod(n\,100))'
11115 Select only frames contained in the 10-20 time interval:
11117 select=between(t\,10\,20)
11121 Select only I frames contained in the 10-20 time interval:
11123 select=between(t\,10\,20)*eq(pict_type\,I)
11127 Select frames with a minimum distance of 10 seconds:
11129 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
11133 Use aselect to select only audio frames with samples number > 100:
11135 aselect='gt(samples_n\,100)'
11139 Create a mosaic of the first scenes:
11141 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
11144 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
11148 Send even and odd frames to separate outputs, and compose them:
11150 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
11154 @section sendcmd, asendcmd
11156 Send commands to filters in the filtergraph.
11158 These filters read commands to be sent to other filters in the
11161 @code{sendcmd} must be inserted between two video filters,
11162 @code{asendcmd} must be inserted between two audio filters, but apart
11163 from that they act the same way.
11165 The specification of commands can be provided in the filter arguments
11166 with the @var{commands} option, or in a file specified by the
11167 @var{filename} option.
11169 These filters accept the following options:
11172 Set the commands to be read and sent to the other filters.
11174 Set the filename of the commands to be read and sent to the other
11178 @subsection Commands syntax
11180 A commands description consists of a sequence of interval
11181 specifications, comprising a list of commands to be executed when a
11182 particular event related to that interval occurs. The occurring event
11183 is typically the current frame time entering or leaving a given time
11186 An interval is specified by the following syntax:
11188 @var{START}[-@var{END}] @var{COMMANDS};
11191 The time interval is specified by the @var{START} and @var{END} times.
11192 @var{END} is optional and defaults to the maximum time.
11194 The current frame time is considered within the specified interval if
11195 it is included in the interval [@var{START}, @var{END}), that is when
11196 the time is greater or equal to @var{START} and is lesser than
11199 @var{COMMANDS} consists of a sequence of one or more command
11200 specifications, separated by ",", relating to that interval. The
11201 syntax of a command specification is given by:
11203 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
11206 @var{FLAGS} is optional and specifies the type of events relating to
11207 the time interval which enable sending the specified command, and must
11208 be a non-null sequence of identifier flags separated by "+" or "|" and
11209 enclosed between "[" and "]".
11211 The following flags are recognized:
11214 The command is sent when the current frame timestamp enters the
11215 specified interval. In other words, the command is sent when the
11216 previous frame timestamp was not in the given interval, and the
11220 The command is sent when the current frame timestamp leaves the
11221 specified interval. In other words, the command is sent when the
11222 previous frame timestamp was in the given interval, and the
11226 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
11229 @var{TARGET} specifies the target of the command, usually the name of
11230 the filter class or a specific filter instance name.
11232 @var{COMMAND} specifies the name of the command for the target filter.
11234 @var{ARG} is optional and specifies the optional list of argument for
11235 the given @var{COMMAND}.
11237 Between one interval specification and another, whitespaces, or
11238 sequences of characters starting with @code{#} until the end of line,
11239 are ignored and can be used to annotate comments.
11241 A simplified BNF description of the commands specification syntax
11244 @var{COMMAND_FLAG} ::= "enter" | "leave"
11245 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
11246 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
11247 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
11248 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
11249 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
11252 @subsection Examples
11256 Specify audio tempo change at second 4:
11258 asendcmd=c='4.0 atempo tempo 1.5',atempo
11262 Specify a list of drawtext and hue commands in a file.
11264 # show text in the interval 5-10
11265 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
11266 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
11268 # desaturate the image in the interval 15-20
11269 15.0-20.0 [enter] hue s 0,
11270 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
11272 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
11274 # apply an exponential saturation fade-out effect, starting from time 25
11275 25 [enter] hue s exp(25-t)
11278 A filtergraph allowing to read and process the above command list
11279 stored in a file @file{test.cmd}, can be specified with:
11281 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
11286 @section setpts, asetpts
11288 Change the PTS (presentation timestamp) of the input frames.
11290 @code{setpts} works on video frames, @code{asetpts} on audio frames.
11292 This filter accepts the following options:
11297 The expression which is evaluated for each frame to construct its timestamp.
11301 The expression is evaluated through the eval API and can contain the following
11306 frame rate, only defined for constant frame-rate video
11309 The presentation timestamp in input
11312 The count of the input frame for video or the number of consumed samples,
11313 not including the current frame for audio, starting from 0.
11315 @item NB_CONSUMED_SAMPLES
11316 The number of consumed samples, not including the current frame (only
11319 @item NB_SAMPLES, S
11320 The number of samples in the current frame (only audio)
11322 @item SAMPLE_RATE, SR
11323 The audio sample rate.
11326 The PTS of the first frame.
11329 the time in seconds of the first frame
11332 State whether the current frame is interlaced.
11335 the time in seconds of the current frame
11338 original position in the file of the frame, or undefined if undefined
11339 for the current frame
11342 The previous input PTS.
11345 previous input time in seconds
11348 The previous output PTS.
11351 previous output time in seconds
11354 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
11358 The wallclock (RTC) time at the start of the movie in microseconds.
11361 The timebase of the input timestamps.
11365 @subsection Examples
11369 Start counting PTS from zero
11371 setpts=PTS-STARTPTS
11375 Apply fast motion effect:
11381 Apply slow motion effect:
11387 Set fixed rate of 25 frames per second:
11393 Set fixed rate 25 fps with some jitter:
11395 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
11399 Apply an offset of 10 seconds to the input PTS:
11405 Generate timestamps from a "live source" and rebase onto the current timebase:
11407 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
11411 Generate timestamps by counting samples:
11418 @section settb, asettb
11420 Set the timebase to use for the output frames timestamps.
11421 It is mainly useful for testing timebase configuration.
11423 It accepts the following parameters:
11428 The expression which is evaluated into the output timebase.
11432 The value for @option{tb} is an arithmetic expression representing a
11433 rational. The expression can contain the constants "AVTB" (the default
11434 timebase), "intb" (the input timebase) and "sr" (the sample rate,
11435 audio only). Default value is "intb".
11437 @subsection Examples
11441 Set the timebase to 1/25:
11447 Set the timebase to 1/10:
11453 Set the timebase to 1001/1000:
11459 Set the timebase to 2*intb:
11465 Set the default timebase value:
11472 Convert input audio to a video output representing
11473 frequency spectrum logarithmically (using constant Q transform with
11474 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
11476 The filter accepts the following options:
11480 Specify transform volume (multiplier) expression. The expression can contain
11483 @item frequency, freq, f
11484 the frequency where transform is evaluated
11485 @item timeclamp, tc
11486 value of timeclamp option
11490 @item a_weighting(f)
11491 A-weighting of equal loudness
11492 @item b_weighting(f)
11493 B-weighting of equal loudness
11494 @item c_weighting(f)
11495 C-weighting of equal loudness
11497 Default value is @code{16}.
11500 Specify transform length expression. The expression can contain variables:
11502 @item frequency, freq, f
11503 the frequency where transform is evaluated
11504 @item timeclamp, tc
11505 value of timeclamp option
11507 Default value is @code{384/f*tc/(384/f+tc)}.
11510 Specify the transform timeclamp. At low frequency, there is trade-off between
11511 accuracy in time domain and frequency domain. If timeclamp is lower,
11512 event in time domain is represented more accurately (such as fast bass drum),
11513 otherwise event in frequency domain is represented more accurately
11514 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
11517 Specify the transform coeffclamp. If coeffclamp is lower, transform is
11518 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
11519 Default value is @code{1.0}.
11522 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
11523 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
11524 Default value is @code{3.0}.
11527 Specify gamma of bargraph. Acceptable value is [1.0, 7.0].
11528 Default value is @code{1.0}.
11531 Specify font file for use with freetype. If not specified, use embedded font.
11534 Specify font color expression. This is arithmetic expression that should return
11535 integer value 0xRRGGBB. The expression can contain variables:
11537 @item frequency, freq, f
11538 the frequency where transform is evaluated
11539 @item timeclamp, tc
11540 value of timeclamp option
11545 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
11546 @item r(x), g(x), b(x)
11547 red, green, and blue value of intensity x
11549 Default value is @code{st(0, (midi(f)-59.5)/12);
11550 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
11551 r(1-ld(1)) + b(ld(1))}
11554 If set to 1 (the default), the video size is 1920x1080 (full HD),
11555 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
11558 Specify video fps. Default value is @code{25}.
11561 Specify number of transform per frame, so there are fps*count transforms
11562 per second. Note that audio data rate must be divisible by fps*count.
11563 Default value is @code{6}.
11567 @subsection Examples
11571 Playing audio while showing the spectrum:
11573 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
11577 Same as above, but with frame rate 30 fps:
11579 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
11583 Playing at 960x540 and lower CPU usage:
11585 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
11589 A1 and its harmonics: A1, A2, (near)E3, A3:
11591 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),
11592 asplit[a][out1]; [a] showcqt [out0]'
11596 Same as above, but with more accuracy in frequency domain (and slower):
11598 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),
11599 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
11603 B-weighting of equal loudness
11605 volume=16*b_weighting(f)
11611 tlength=100/f*tc/(100/f+tc)
11615 Custom fontcolor, C-note is colored green, others are colored blue
11617 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))'
11621 Custom gamma, now spectrum is linear to the amplitude.
11628 @section showspectrum
11630 Convert input audio to a video output, representing the audio frequency
11633 The filter accepts the following options:
11637 Specify the video size for the output. For the syntax of this option, check the
11638 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11639 Default value is @code{640x512}.
11642 Specify how the spectrum should slide along the window.
11644 It accepts the following values:
11647 the samples start again on the left when they reach the right
11649 the samples scroll from right to left
11651 frames are only produced when the samples reach the right
11654 Default value is @code{replace}.
11657 Specify display mode.
11659 It accepts the following values:
11662 all channels are displayed in the same row
11664 all channels are displayed in separate rows
11667 Default value is @samp{combined}.
11670 Specify display color mode.
11672 It accepts the following values:
11675 each channel is displayed in a separate color
11677 each channel is is displayed using the same color scheme
11680 Default value is @samp{channel}.
11683 Specify scale used for calculating intensity color values.
11685 It accepts the following values:
11690 square root, default
11697 Default value is @samp{sqrt}.
11700 Set saturation modifier for displayed colors. Negative values provide
11701 alternative color scheme. @code{0} is no saturation at all.
11702 Saturation must be in [-10.0, 10.0] range.
11703 Default value is @code{1}.
11706 Set window function.
11708 It accepts the following values:
11711 No samples pre-processing (do not expect this to be faster)
11720 Default value is @code{hann}.
11723 The usage is very similar to the showwaves filter; see the examples in that
11726 @subsection Examples
11730 Large window with logarithmic color scaling:
11732 showspectrum=s=1280x480:scale=log
11736 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
11738 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
11739 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
11745 Convert input audio to a video output, representing the samples waves.
11747 The filter accepts the following options:
11751 Specify the video size for the output. For the syntax of this option, check the
11752 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11753 Default value is @code{600x240}.
11758 Available values are:
11761 Draw a point for each sample.
11764 Draw a vertical line for each sample.
11767 Draw a point for each sample and a line between them.
11770 Draw a centered vertical line for each sample.
11773 Default value is @code{point}.
11776 Set the number of samples which are printed on the same column. A
11777 larger value will decrease the frame rate. Must be a positive
11778 integer. This option can be set only if the value for @var{rate}
11779 is not explicitly specified.
11782 Set the (approximate) output frame rate. This is done by setting the
11783 option @var{n}. Default value is "25".
11785 @item split_channels
11786 Set if channels should be drawn separately or overlap. Default value is 0.
11790 @subsection Examples
11794 Output the input file audio and the corresponding video representation
11797 amovie=a.mp3,asplit[out0],showwaves[out1]
11801 Create a synthetic signal and show it with showwaves, forcing a
11802 frame rate of 30 frames per second:
11804 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
11808 @section showwavespic
11810 Convert input audio to a single video frame, representing the samples waves.
11812 The filter accepts the following options:
11816 Specify the video size for the output. For the syntax of this option, check the
11817 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11818 Default value is @code{600x240}.
11820 @item split_channels
11821 Set if channels should be drawn separately or overlap. Default value is 0.
11824 @subsection Examples
11828 Extract a channel split representation of the wave form of a whole audio track
11829 in a 1024x800 picture using @command{ffmpeg}:
11831 ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png
11835 @section split, asplit
11837 Split input into several identical outputs.
11839 @code{asplit} works with audio input, @code{split} with video.
11841 The filter accepts a single parameter which specifies the number of outputs. If
11842 unspecified, it defaults to 2.
11844 @subsection Examples
11848 Create two separate outputs from the same input:
11850 [in] split [out0][out1]
11854 To create 3 or more outputs, you need to specify the number of
11857 [in] asplit=3 [out0][out1][out2]
11861 Create two separate outputs from the same input, one cropped and
11864 [in] split [splitout1][splitout2];
11865 [splitout1] crop=100:100:0:0 [cropout];
11866 [splitout2] pad=200:200:100:100 [padout];
11870 Create 5 copies of the input audio with @command{ffmpeg}:
11872 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
11878 Receive commands sent through a libzmq client, and forward them to
11879 filters in the filtergraph.
11881 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
11882 must be inserted between two video filters, @code{azmq} between two
11885 To enable these filters you need to install the libzmq library and
11886 headers and configure FFmpeg with @code{--enable-libzmq}.
11888 For more information about libzmq see:
11889 @url{http://www.zeromq.org/}
11891 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
11892 receives messages sent through a network interface defined by the
11893 @option{bind_address} option.
11895 The received message must be in the form:
11897 @var{TARGET} @var{COMMAND} [@var{ARG}]
11900 @var{TARGET} specifies the target of the command, usually the name of
11901 the filter class or a specific filter instance name.
11903 @var{COMMAND} specifies the name of the command for the target filter.
11905 @var{ARG} is optional and specifies the optional argument list for the
11906 given @var{COMMAND}.
11908 Upon reception, the message is processed and the corresponding command
11909 is injected into the filtergraph. Depending on the result, the filter
11910 will send a reply to the client, adopting the format:
11912 @var{ERROR_CODE} @var{ERROR_REASON}
11916 @var{MESSAGE} is optional.
11918 @subsection Examples
11920 Look at @file{tools/zmqsend} for an example of a zmq client which can
11921 be used to send commands processed by these filters.
11923 Consider the following filtergraph generated by @command{ffplay}
11925 ffplay -dumpgraph 1 -f lavfi "
11926 color=s=100x100:c=red [l];
11927 color=s=100x100:c=blue [r];
11928 nullsrc=s=200x100, zmq [bg];
11929 [bg][l] overlay [bg+l];
11930 [bg+l][r] overlay=x=100 "
11933 To change the color of the left side of the video, the following
11934 command can be used:
11936 echo Parsed_color_0 c yellow | tools/zmqsend
11939 To change the right side:
11941 echo Parsed_color_1 c pink | tools/zmqsend
11944 @c man end MULTIMEDIA FILTERS
11946 @chapter Multimedia Sources
11947 @c man begin MULTIMEDIA SOURCES
11949 Below is a description of the currently available multimedia sources.
11953 This is the same as @ref{movie} source, except it selects an audio
11959 Read audio and/or video stream(s) from a movie container.
11961 It accepts the following parameters:
11965 The name of the resource to read (not necessarily a file; it can also be a
11966 device or a stream accessed through some protocol).
11968 @item format_name, f
11969 Specifies the format assumed for the movie to read, and can be either
11970 the name of a container or an input device. If not specified, the
11971 format is guessed from @var{movie_name} or by probing.
11973 @item seek_point, sp
11974 Specifies the seek point in seconds. The frames will be output
11975 starting from this seek point. The parameter is evaluated with
11976 @code{av_strtod}, so the numerical value may be suffixed by an IS
11977 postfix. The default value is "0".
11980 Specifies the streams to read. Several streams can be specified,
11981 separated by "+". The source will then have as many outputs, in the
11982 same order. The syntax is explained in the ``Stream specifiers''
11983 section in the ffmpeg manual. Two special names, "dv" and "da" specify
11984 respectively the default (best suited) video and audio stream. Default
11985 is "dv", or "da" if the filter is called as "amovie".
11987 @item stream_index, si
11988 Specifies the index of the video stream to read. If the value is -1,
11989 the most suitable video stream will be automatically selected. The default
11990 value is "-1". Deprecated. If the filter is called "amovie", it will select
11991 audio instead of video.
11994 Specifies how many times to read the stream in sequence.
11995 If the value is less than 1, the stream will be read again and again.
11996 Default value is "1".
11998 Note that when the movie is looped the source timestamps are not
11999 changed, so it will generate non monotonically increasing timestamps.
12002 It allows overlaying a second video on top of the main input of
12003 a filtergraph, as shown in this graph:
12005 input -----------> deltapts0 --> overlay --> output
12008 movie --> scale--> deltapts1 -------+
12010 @subsection Examples
12014 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
12015 on top of the input labelled "in":
12017 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
12018 [in] setpts=PTS-STARTPTS [main];
12019 [main][over] overlay=16:16 [out]
12023 Read from a video4linux2 device, and overlay it on top of the input
12026 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
12027 [in] setpts=PTS-STARTPTS [main];
12028 [main][over] overlay=16:16 [out]
12032 Read the first video stream and the audio stream with id 0x81 from
12033 dvd.vob; the video is connected to the pad named "video" and the audio is
12034 connected to the pad named "audio":
12036 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
12040 @c man end MULTIMEDIA SOURCES