1 @chapter Filtering Introduction
2 @c man begin FILTERING INTRODUCTION
4 Filtering in FFmpeg is enabled through the libavfilter library.
6 In libavfilter, a filter can have multiple inputs and multiple
8 To illustrate the sorts of things that are possible, we consider the
13 input --> split ---------------------> overlay --> output
16 +-----> crop --> vflip -------+
19 This filtergraph splits the input stream in two streams, then sends one
20 stream through the crop filter and the vflip filter, before merging it
21 back with the other stream by overlaying it on top. You can use the
22 following command to achieve this:
25 ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
28 The result will be that the top half of the video is mirrored
29 onto the bottom half of the output video.
31 Filters in the same linear chain are separated by commas, and distinct
32 linear chains of filters are separated by semicolons. In our example,
33 @var{crop,vflip} are in one linear chain, @var{split} and
34 @var{overlay} are separately in another. The points where the linear
35 chains join are labelled by names enclosed in square brackets. In the
36 example, the split filter generates two outputs that are associated to
37 the labels @var{[main]} and @var{[tmp]}.
39 The stream sent to the second output of @var{split}, labelled as
40 @var{[tmp]}, is processed through the @var{crop} filter, which crops
41 away the lower half part of the video, and then vertically flipped. The
42 @var{overlay} filter takes in input the first unchanged output of the
43 split filter (which was labelled as @var{[main]}), and overlay on its
44 lower half the output generated by the @var{crop,vflip} filterchain.
46 Some filters take in input a list of parameters: they are specified
47 after the filter name and an equal sign, and are separated from each other
50 There exist so-called @var{source filters} that do not have an
51 audio/video input, and @var{sink filters} that will not have audio/video
54 @c man end FILTERING INTRODUCTION
57 @c man begin GRAPH2DOT
59 The @file{graph2dot} program included in the FFmpeg @file{tools}
60 directory can be used to parse a filtergraph description and issue a
61 corresponding textual representation in the dot language.
68 to see how to use @file{graph2dot}.
70 You can then pass the dot description to the @file{dot} program (from
71 the graphviz suite of programs) and obtain a graphical representation
74 For example the sequence of commands:
76 echo @var{GRAPH_DESCRIPTION} | \
77 tools/graph2dot -o graph.tmp && \
78 dot -Tpng graph.tmp -o graph.png && \
82 can be used to create and display an image representing the graph
83 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
84 a complete self-contained graph, with its inputs and outputs explicitly defined.
85 For example if your command line is of the form:
87 ffmpeg -i infile -vf scale=640:360 outfile
89 your @var{GRAPH_DESCRIPTION} string will need to be of the form:
91 nullsrc,scale=640:360,nullsink
93 you may also need to set the @var{nullsrc} parameters and add a @var{format}
94 filter in order to simulate a specific input file.
98 @chapter Filtergraph description
99 @c man begin FILTERGRAPH DESCRIPTION
101 A filtergraph is a directed graph of connected filters. It can contain
102 cycles, and there can be multiple links between a pair of
103 filters. Each link has one input pad on one side connecting it to one
104 filter from which it takes its input, and one output pad on the other
105 side connecting it to one filter accepting its output.
107 Each filter in a filtergraph is an instance of a filter class
108 registered in the application, which defines the features and the
109 number of input and output pads of the filter.
111 A filter with no input pads is called a "source", and a filter with no
112 output pads is called a "sink".
114 @anchor{Filtergraph syntax}
115 @section Filtergraph syntax
117 A filtergraph has a textual representation, which is recognized by the
118 @option{-filter}/@option{-vf}/@option{-af} and
119 @option{-filter_complex} options in @command{ffmpeg} and
120 @option{-vf}/@option{-af} in @command{ffplay}, and by the
121 @code{avfilter_graph_parse_ptr()} function defined in
122 @file{libavfilter/avfilter.h}.
124 A filterchain consists of a sequence of connected filters, each one
125 connected to the previous one in the sequence. A filterchain is
126 represented by a list of ","-separated filter descriptions.
128 A filtergraph consists of a sequence of filterchains. A sequence of
129 filterchains is represented by a list of ";"-separated filterchain
132 A filter is represented by a string of the form:
133 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
135 @var{filter_name} is the name of the filter class of which the
136 described filter is an instance of, and has to be the name of one of
137 the filter classes registered in the program.
138 The name of the filter class is optionally followed by a string
141 @var{arguments} is a string which contains the parameters used to
142 initialize the filter instance. It may have one of two forms:
146 A ':'-separated list of @var{key=value} pairs.
149 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
150 the option names in the order they are declared. E.g. the @code{fade} filter
151 declares three options in this order -- @option{type}, @option{start_frame} and
152 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
153 @var{in} is assigned to the option @option{type}, @var{0} to
154 @option{start_frame} and @var{30} to @option{nb_frames}.
157 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
158 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
159 follow the same constraints order of the previous point. The following
160 @var{key=value} pairs can be set in any preferred order.
164 If the option value itself is a list of items (e.g. the @code{format} filter
165 takes a list of pixel formats), the items in the list are usually separated by
168 The list of arguments can be quoted using the character "'" as initial
169 and ending mark, and the character '\' for escaping the characters
170 within the quoted text; otherwise the argument string is considered
171 terminated when the next special character (belonging to the set
172 "[]=;,") is encountered.
174 The name and arguments of the filter are optionally preceded and
175 followed by a list of link labels.
176 A link label allows one to name a link and associate it to a filter output
177 or input pad. The preceding labels @var{in_link_1}
178 ... @var{in_link_N}, are associated to the filter input pads,
179 the following labels @var{out_link_1} ... @var{out_link_M}, are
180 associated to the output pads.
182 When two link labels with the same name are found in the
183 filtergraph, a link between the corresponding input and output pad is
186 If an output pad is not labelled, it is linked by default to the first
187 unlabelled input pad of the next filter in the filterchain.
188 For example in the filterchain
190 nullsrc, split[L1], [L2]overlay, nullsink
192 the split filter instance has two output pads, and the overlay filter
193 instance two input pads. The first output pad of split is labelled
194 "L1", the first input pad of overlay is labelled "L2", and the second
195 output pad of split is linked to the second input pad of overlay,
196 which are both unlabelled.
198 In a filter description, if the input label of the first filter is not
199 specified, "in" is assumed; if the output label of the last filter is not
200 specified, "out" is assumed.
202 In a complete filterchain all the unlabelled filter input and output
203 pads must be connected. A filtergraph is considered valid if all the
204 filter input and output pads of all the filterchains are connected.
206 Libavfilter will automatically insert @ref{scale} filters where format
207 conversion is required. It is possible to specify swscale flags
208 for those automatically inserted scalers by prepending
209 @code{sws_flags=@var{flags};}
210 to the filtergraph description.
212 Here is a BNF description of the filtergraph syntax:
214 @var{NAME} ::= sequence of alphanumeric characters and '_'
215 @var{LINKLABEL} ::= "[" @var{NAME} "]"
216 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
217 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
218 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
219 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
220 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
223 @section Notes on filtergraph escaping
225 Filtergraph description composition entails several levels of
226 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
227 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
228 information about the employed escaping procedure.
230 A first level escaping affects the content of each filter option
231 value, which may contain the special character @code{:} used to
232 separate values, or one of the escaping characters @code{\'}.
234 A second level escaping affects the whole filter description, which
235 may contain the escaping characters @code{\'} or the special
236 characters @code{[],;} used by the filtergraph description.
238 Finally, when you specify a filtergraph on a shell commandline, you
239 need to perform a third level escaping for the shell special
240 characters contained within it.
242 For example, consider the following string to be embedded in
243 the @ref{drawtext} filter description @option{text} value:
245 this is a 'string': may contain one, or more, special characters
248 This string contains the @code{'} special escaping character, and the
249 @code{:} special character, so it needs to be escaped in this way:
251 text=this is a \'string\'\: may contain one, or more, special characters
254 A second level of escaping is required when embedding the filter
255 description in a filtergraph description, in order to escape all the
256 filtergraph special characters. Thus the example above becomes:
258 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
260 (note that in addition to the @code{\'} escaping special characters,
261 also @code{,} needs to be escaped).
263 Finally an additional level of escaping is needed when writing the
264 filtergraph description in a shell command, which depends on the
265 escaping rules of the adopted shell. For example, assuming that
266 @code{\} is special and needs to be escaped with another @code{\}, the
267 previous string will finally result in:
269 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
272 @chapter Timeline editing
274 Some filters support a generic @option{enable} option. For the filters
275 supporting timeline editing, this option can be set to an expression which is
276 evaluated before sending a frame to the filter. If the evaluation is non-zero,
277 the filter will be enabled, otherwise the frame will be sent unchanged to the
278 next filter in the filtergraph.
280 The expression accepts the following values:
283 timestamp expressed in seconds, NAN if the input timestamp is unknown
286 sequential number of the input frame, starting from 0
289 the position in the file of the input frame, NAN if unknown
293 width and height of the input frame if video
296 Additionally, these filters support an @option{enable} command that can be used
297 to re-define the expression.
299 Like any other filtering option, the @option{enable} option follows the same
302 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
303 minutes, and a @ref{curves} filter starting at 3 seconds:
305 smartblur = enable='between(t,10,3*60)',
306 curves = enable='gte(t,3)' : preset=cross_process
309 @c man end FILTERGRAPH DESCRIPTION
311 @chapter Audio Filters
312 @c man begin AUDIO FILTERS
314 When you configure your FFmpeg build, you can disable any of the
315 existing filters using @code{--disable-filters}.
316 The configure output will show the audio filters included in your
319 Below is a description of the currently available audio filters.
323 Delay one or more audio channels.
325 Samples in delayed channel are filled with silence.
327 The filter accepts the following option:
331 Set list of delays in milliseconds for each channel separated by '|'.
332 At least one delay greater than 0 should be provided.
333 Unused delays will be silently ignored. If number of given delays is
334 smaller than number of channels all remaining channels will not be delayed.
341 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
342 the second channel (and any other channels that may be present) unchanged.
350 Apply echoing to the input audio.
352 Echoes are reflected sound and can occur naturally amongst mountains
353 (and sometimes large buildings) when talking or shouting; digital echo
354 effects emulate this behaviour and are often used to help fill out the
355 sound of a single instrument or vocal. The time difference between the
356 original signal and the reflection is the @code{delay}, and the
357 loudness of the reflected signal is the @code{decay}.
358 Multiple echoes can have different delays and decays.
360 A description of the accepted parameters follows.
364 Set input gain of reflected signal. Default is @code{0.6}.
367 Set output gain of reflected signal. Default is @code{0.3}.
370 Set list of time intervals in milliseconds between original signal and reflections
371 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
372 Default is @code{1000}.
375 Set list of loudnesses of reflected signals separated by '|'.
376 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
377 Default is @code{0.5}.
384 Make it sound as if there are twice as many instruments as are actually playing:
386 aecho=0.8:0.88:60:0.4
390 If delay is very short, then it sound like a (metallic) robot playing music:
396 A longer delay will sound like an open air concert in the mountains:
398 aecho=0.8:0.9:1000:0.3
402 Same as above but with one more mountain:
404 aecho=0.8:0.9:1000|1800:0.3|0.25
410 Modify an audio signal according to the specified expressions.
412 This filter accepts one or more expressions (one for each channel),
413 which are evaluated and used to modify a corresponding audio signal.
415 It accepts the following parameters:
419 Set the '|'-separated expressions list for each separate channel. If
420 the number of input channels is greater than the number of
421 expressions, the last specified expression is used for the remaining
424 @item channel_layout, c
425 Set output channel layout. If not specified, the channel layout is
426 specified by the number of expressions. If set to @samp{same}, it will
427 use by default the same input channel layout.
430 Each expression in @var{exprs} can contain the following constants and functions:
434 channel number of the current expression
437 number of the evaluated sample, starting from 0
443 time of the evaluated sample expressed in seconds
446 @item nb_out_channels
447 input and output number of channels
450 the value of input channel with number @var{CH}
453 Note: this filter is slow. For faster processing you should use a
462 aeval=val(ch)/2:c=same
466 Invert phase of the second channel:
474 Apply fade-in/out effect to input audio.
476 A description of the accepted parameters follows.
480 Specify the effect type, can be either @code{in} for fade-in, or
481 @code{out} for a fade-out effect. Default is @code{in}.
483 @item start_sample, ss
484 Specify the number of the start sample for starting to apply the fade
485 effect. Default is 0.
488 Specify the number of samples for which the fade effect has to last. At
489 the end of the fade-in effect the output audio will have the same
490 volume as the input audio, at the end of the fade-out transition
491 the output audio will be silence. Default is 44100.
494 Specify the start time of the fade effect. Default is 0.
495 The value must be specified as a time duration; see
496 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
497 for the accepted syntax.
498 If set this option is used instead of @var{start_sample}.
501 Specify the duration of the fade effect. See
502 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
503 for the accepted syntax.
504 At the end of the fade-in effect the output audio will have the same
505 volume as the input audio, at the end of the fade-out transition
506 the output audio will be silence.
507 By default the duration is determined by @var{nb_samples}.
508 If set this option is used instead of @var{nb_samples}.
511 Set curve for fade transition.
513 It accepts the following values:
516 select triangular, linear slope (default)
518 select quarter of sine wave
520 select half of sine wave
522 select exponential sine wave
526 select inverted parabola
542 Fade in first 15 seconds of audio:
548 Fade out last 25 seconds of a 900 seconds audio:
550 afade=t=out:st=875:d=25
557 Set output format constraints for the input audio. The framework will
558 negotiate the most appropriate format to minimize conversions.
560 It accepts the following parameters:
564 A '|'-separated list of requested sample formats.
567 A '|'-separated list of requested sample rates.
569 @item channel_layouts
570 A '|'-separated list of requested channel layouts.
572 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
573 for the required syntax.
576 If a parameter is omitted, all values are allowed.
578 Force the output to either unsigned 8-bit or signed 16-bit stereo
580 aformat=sample_fmts=u8|s16:channel_layouts=stereo
585 Apply a two-pole all-pass filter with central frequency (in Hz)
586 @var{frequency}, and filter-width @var{width}.
587 An all-pass filter changes the audio's frequency to phase relationship
588 without changing its frequency to amplitude relationship.
590 The filter accepts the following options:
597 Set method to specify band-width of filter.
610 Specify the band-width of a filter in width_type units.
615 Merge two or more audio streams into a single multi-channel stream.
617 The filter accepts the following options:
622 Set the number of inputs. Default is 2.
626 If the channel layouts of the inputs are disjoint, and therefore compatible,
627 the channel layout of the output will be set accordingly and the channels
628 will be reordered as necessary. If the channel layouts of the inputs are not
629 disjoint, the output will have all the channels of the first input then all
630 the channels of the second input, in that order, and the channel layout of
631 the output will be the default value corresponding to the total number of
634 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
635 is FC+BL+BR, then the output will be in 5.1, with the channels in the
636 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
637 first input, b1 is the first channel of the second input).
639 On the other hand, if both input are in stereo, the output channels will be
640 in the default order: a1, a2, b1, b2, and the channel layout will be
641 arbitrarily set to 4.0, which may or may not be the expected value.
643 All inputs must have the same sample rate, and format.
645 If inputs do not have the same duration, the output will stop with the
652 Merge two mono files into a stereo stream:
654 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
658 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
660 ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv
666 Mixes multiple audio inputs into a single output.
668 Note that this filter only supports float samples (the @var{amerge}
669 and @var{pan} audio filters support many formats). If the @var{amix}
670 input has integer samples then @ref{aresample} will be automatically
671 inserted to perform the conversion to float samples.
675 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
677 will mix 3 input audio streams to a single output with the same duration as the
678 first input and a dropout transition time of 3 seconds.
680 It accepts the following parameters:
684 The number of inputs. If unspecified, it defaults to 2.
687 How to determine the end-of-stream.
691 The duration of the longest input. (default)
694 The duration of the shortest input.
697 The duration of the first input.
701 @item dropout_transition
702 The transition time, in seconds, for volume renormalization when an input
703 stream ends. The default value is 2 seconds.
709 Pass the audio source unchanged to the output.
713 Pad the end of an audio stream with silence.
715 This can be used together with @command{ffmpeg} @option{-shortest} to
716 extend audio streams to the same length as the video stream.
718 A description of the accepted options follows.
722 Set silence packet size. Default value is 4096.
725 Set the number of samples of silence to add to the end. After the
726 value is reached, the stream is terminated. This option is mutually
727 exclusive with @option{whole_len}.
730 Set the minimum total number of samples in the output audio stream. If
731 the value is longer than the input audio length, silence is added to
732 the end, until the value is reached. This option is mutually exclusive
733 with @option{pad_len}.
736 If neither the @option{pad_len} nor the @option{whole_len} option is
737 set, the filter will add silence to the end of the input stream
744 Add 1024 samples of silence to the end of the input:
750 Make sure the audio output will contain at least 10000 samples, pad
751 the input with silence if required:
757 Use @command{ffmpeg} to pad the audio input with silence, so that the
758 video stream will always result the shortest and will be converted
759 until the end in the output file when using the @option{shortest}
762 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
767 Add a phasing effect to the input audio.
769 A phaser filter creates series of peaks and troughs in the frequency spectrum.
770 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
772 A description of the accepted parameters follows.
776 Set input gain. Default is 0.4.
779 Set output gain. Default is 0.74
782 Set delay in milliseconds. Default is 3.0.
785 Set decay. Default is 0.4.
788 Set modulation speed in Hz. Default is 0.5.
791 Set modulation type. Default is triangular.
793 It accepts the following values:
803 Resample the input audio to the specified parameters, using the
804 libswresample library. If none are specified then the filter will
805 automatically convert between its input and output.
807 This filter is also able to stretch/squeeze the audio data to make it match
808 the timestamps or to inject silence / cut out audio to make it match the
809 timestamps, do a combination of both or do neither.
811 The filter accepts the syntax
812 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
813 expresses a sample rate and @var{resampler_options} is a list of
814 @var{key}=@var{value} pairs, separated by ":". See the
815 ffmpeg-resampler manual for the complete list of supported options.
821 Resample the input audio to 44100Hz:
827 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
828 samples per second compensation:
834 @section asetnsamples
836 Set the number of samples per each output audio frame.
838 The last output packet may contain a different number of samples, as
839 the filter will flush all the remaining samples when the input audio
842 The filter accepts the following options:
846 @item nb_out_samples, n
847 Set the number of frames per each output audio frame. The number is
848 intended as the number of samples @emph{per each channel}.
849 Default value is 1024.
852 If set to 1, the filter will pad the last audio frame with zeroes, so
853 that the last frame will contain the same number of samples as the
854 previous ones. Default value is 1.
857 For example, to set the number of per-frame samples to 1234 and
858 disable padding for the last frame, use:
860 asetnsamples=n=1234:p=0
865 Set the sample rate without altering the PCM data.
866 This will result in a change of speed and pitch.
868 The filter accepts the following options:
872 Set the output sample rate. Default is 44100 Hz.
877 Show a line containing various information for each input audio frame.
878 The input audio is not modified.
880 The shown line contains a sequence of key/value pairs of the form
881 @var{key}:@var{value}.
883 The following values are shown in the output:
887 The (sequential) number of the input frame, starting from 0.
890 The presentation timestamp of the input frame, in time base units; the time base
891 depends on the filter input pad, and is usually 1/@var{sample_rate}.
894 The presentation timestamp of the input frame in seconds.
897 position of the frame in the input stream, -1 if this information in
898 unavailable and/or meaningless (for example in case of synthetic audio)
907 The sample rate for the audio frame.
910 The number of samples (per channel) in the frame.
913 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
914 audio, the data is treated as if all the planes were concatenated.
916 @item plane_checksums
917 A list of Adler-32 checksums for each data plane.
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 Draw a colored box on the input image.
3735 It accepts the following parameters:
3740 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3744 The expressions which specify the width and height of the box; if 0 they are interpreted as
3745 the input width and height. It defaults to 0.
3748 Specify the color of the box to write. For the general syntax of this option,
3749 check the "Color" section in the ffmpeg-utils manual. If the special
3750 value @code{invert} is used, the box edge color is the same as the
3751 video with inverted luma.
3754 The expression which sets the thickness of the box edge. Default value is @code{3}.
3756 See below for the list of accepted constants.
3759 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3760 following constants:
3764 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3768 horizontal and vertical chroma subsample values. For example for the
3769 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3773 The input width and height.
3776 The input sample aspect ratio.
3780 The x and y offset coordinates where the box is drawn.
3784 The width and height of the drawn box.
3787 The thickness of the drawn box.
3789 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3790 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3794 @subsection Examples
3798 Draw a black box around the edge of the input image:
3804 Draw a box with color red and an opacity of 50%:
3806 drawbox=10:20:200:60:red@@0.5
3809 The previous example can be specified as:
3811 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3815 Fill the box with pink color:
3817 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3821 Draw a 2-pixel red 2.40:1 mask:
3823 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
3829 Draw a grid on the input image.
3831 It accepts the following parameters:
3836 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3840 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3841 input width and height, respectively, minus @code{thickness}, so image gets
3842 framed. Default to 0.
3845 Specify the color of the grid. For the general syntax of this option,
3846 check the "Color" section in the ffmpeg-utils manual. If the special
3847 value @code{invert} is used, the grid color is the same as the
3848 video with inverted luma.
3851 The expression which sets the thickness of the grid line. Default value is @code{1}.
3853 See below for the list of accepted constants.
3856 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3857 following constants:
3861 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3865 horizontal and vertical chroma subsample values. For example for the
3866 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3870 The input grid cell width and height.
3873 The input sample aspect ratio.
3877 The x and y coordinates of some point of grid intersection (meant to configure offset).
3881 The width and height of the drawn cell.
3884 The thickness of the drawn cell.
3886 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3887 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3891 @subsection Examples
3895 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3897 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3901 Draw a white 3x3 grid with an opacity of 50%:
3903 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3910 Draw a text string or text from a specified file on top of a video, using the
3911 libfreetype library.
3913 To enable compilation of this filter, you need to configure FFmpeg with
3914 @code{--enable-libfreetype}.
3915 To enable default font fallback and the @var{font} option you need to
3916 configure FFmpeg with @code{--enable-libfontconfig}.
3917 To enable the @var{text_shaping} option, you need to configure FFmpeg with
3918 @code{--enable-libfribidi}.
3922 It accepts the following parameters:
3927 Used to draw a box around text using the background color.
3928 The value must be either 1 (enable) or 0 (disable).
3929 The default value of @var{box} is 0.
3932 The color to be used for drawing box around text. For the syntax of this
3933 option, check the "Color" section in the ffmpeg-utils manual.
3935 The default value of @var{boxcolor} is "white".
3938 Set the width of the border to be drawn around the text using @var{bordercolor}.
3939 The default value of @var{borderw} is 0.
3942 Set the color to be used for drawing border around text. For the syntax of this
3943 option, check the "Color" section in the ffmpeg-utils manual.
3945 The default value of @var{bordercolor} is "black".
3948 Select how the @var{text} is expanded. Can be either @code{none},
3949 @code{strftime} (deprecated) or
3950 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3954 If true, check and fix text coords to avoid clipping.
3957 The color to be used for drawing fonts. For the syntax of this option, check
3958 the "Color" section in the ffmpeg-utils manual.
3960 The default value of @var{fontcolor} is "black".
3962 @item fontcolor_expr
3963 String which is expanded the same way as @var{text} to obtain dynamic
3964 @var{fontcolor} value. By default this option has empty value and is not
3965 processed. When this option is set, it overrides @var{fontcolor} option.
3968 The font family to be used for drawing text. By default Sans.
3971 The font file to be used for drawing text. The path must be included.
3972 This parameter is mandatory if the fontconfig support is disabled.
3975 The font size to be used for drawing text.
3976 The default value of @var{fontsize} is 16.
3979 If set to 1, attempt to shape the text (for example, reverse the order of
3980 right-to-left text and join Arabic characters) before drawing it.
3981 Otherwise, just draw the text exactly as given.
3982 By default 1 (if supported).
3985 The flags to be used for loading the fonts.
3987 The flags map the corresponding flags supported by libfreetype, and are
3988 a combination of the following values:
3995 @item vertical_layout
3996 @item force_autohint
3999 @item ignore_global_advance_width
4001 @item ignore_transform
4007 Default value is "default".
4009 For more information consult the documentation for the FT_LOAD_*
4013 The color to be used for drawing a shadow behind the drawn text. For the
4014 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
4016 The default value of @var{shadowcolor} is "black".
4020 The x and y offsets for the text shadow position with respect to the
4021 position of the text. They can be either positive or negative
4022 values. The default value for both is "0".
4025 The starting frame number for the n/frame_num variable. The default value
4029 The size in number of spaces to use for rendering the tab.
4033 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
4034 format. It can be used with or without text parameter. @var{timecode_rate}
4035 option must be specified.
4037 @item timecode_rate, rate, r
4038 Set the timecode frame rate (timecode only).
4041 The text string to be drawn. The text must be a sequence of UTF-8
4043 This parameter is mandatory if no file is specified with the parameter
4047 A text file containing text to be drawn. The text must be a sequence
4048 of UTF-8 encoded characters.
4050 This parameter is mandatory if no text string is specified with the
4051 parameter @var{text}.
4053 If both @var{text} and @var{textfile} are specified, an error is thrown.
4056 If set to 1, the @var{textfile} will be reloaded before each frame.
4057 Be sure to update it atomically, or it may be read partially, or even fail.
4061 The expressions which specify the offsets where text will be drawn
4062 within the video frame. They are relative to the top/left border of the
4065 The default value of @var{x} and @var{y} is "0".
4067 See below for the list of accepted constants and functions.
4070 The parameters for @var{x} and @var{y} are expressions containing the
4071 following constants and functions:
4075 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
4079 horizontal and vertical chroma subsample values. For example for the
4080 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4083 the height of each text line
4091 @item max_glyph_a, ascent
4092 the maximum distance from the baseline to the highest/upper grid
4093 coordinate used to place a glyph outline point, for all the rendered
4095 It is a positive value, due to the grid's orientation with the Y axis
4098 @item max_glyph_d, descent
4099 the maximum distance from the baseline to the lowest grid coordinate
4100 used to place a glyph outline point, for all the rendered glyphs.
4101 This is a negative value, due to the grid's orientation, with the Y axis
4105 maximum glyph height, that is the maximum height for all the glyphs
4106 contained in the rendered text, it is equivalent to @var{ascent} -
4110 maximum glyph width, that is the maximum width for all the glyphs
4111 contained in the rendered text
4114 the number of input frame, starting from 0
4116 @item rand(min, max)
4117 return a random number included between @var{min} and @var{max}
4120 The input sample aspect ratio.
4123 timestamp expressed in seconds, NAN if the input timestamp is unknown
4126 the height of the rendered text
4129 the width of the rendered text
4133 the x and y offset coordinates where the text is drawn.
4135 These parameters allow the @var{x} and @var{y} expressions to refer
4136 each other, so you can for example specify @code{y=x/dar}.
4139 @anchor{drawtext_expansion}
4140 @subsection Text expansion
4142 If @option{expansion} is set to @code{strftime},
4143 the filter recognizes strftime() sequences in the provided text and
4144 expands them accordingly. Check the documentation of strftime(). This
4145 feature is deprecated.
4147 If @option{expansion} is set to @code{none}, the text is printed verbatim.
4149 If @option{expansion} is set to @code{normal} (which is the default),
4150 the following expansion mechanism is used.
4152 The backslash character '\', followed by any character, always expands to
4153 the second character.
4155 Sequence of the form @code{%@{...@}} are expanded. The text between the
4156 braces is a function name, possibly followed by arguments separated by ':'.
4157 If the arguments contain special characters or delimiters (':' or '@}'),
4158 they should be escaped.
4160 Note that they probably must also be escaped as the value for the
4161 @option{text} option in the filter argument string and as the filter
4162 argument in the filtergraph description, and possibly also for the shell,
4163 that makes up to four levels of escaping; using a text file avoids these
4166 The following functions are available:
4171 The expression evaluation result.
4173 It must take one argument specifying the expression to be evaluated,
4174 which accepts the same constants and functions as the @var{x} and
4175 @var{y} values. Note that not all constants should be used, for
4176 example the text size is not known when evaluating the expression, so
4177 the constants @var{text_w} and @var{text_h} will have an undefined
4180 @item expr_int_format, eif
4181 Evaluate the expression's value and output as formatted integer.
4183 The first argument is the expression to be evaluated, just as for the @var{expr} function.
4184 The second argument specifies the output format. Allowed values are 'x', 'X', 'd' and
4185 'u'. They are treated exactly as in the printf function.
4186 The third parameter is optional and sets the number of positions taken by the output.
4187 It can be used to add padding with zeros from the left.
4190 The time at which the filter is running, expressed in UTC.
4191 It can accept an argument: a strftime() format string.
4194 The time at which the filter is running, expressed in the local time zone.
4195 It can accept an argument: a strftime() format string.
4198 Frame metadata. It must take one argument specifying metadata key.
4201 The frame number, starting from 0.
4204 A 1 character description of the current picture type.
4207 The timestamp of the current frame.
4208 It can take up to two arguments.
4210 The first argument is the format of the timestamp; it defaults to @code{flt}
4211 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
4212 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
4214 The second argument is an offset added to the timestamp.
4218 @subsection Examples
4222 Draw "Test Text" with font FreeSerif, using the default values for the
4223 optional parameters.
4226 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
4230 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
4231 and y=50 (counting from the top-left corner of the screen), text is
4232 yellow with a red box around it. Both the text and the box have an
4236 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
4237 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
4240 Note that the double quotes are not necessary if spaces are not used
4241 within the parameter list.
4244 Show the text at the center of the video frame:
4246 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
4250 Show a text line sliding from right to left in the last row of the video
4251 frame. The file @file{LONG_LINE} is assumed to contain a single line
4254 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
4258 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
4260 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
4264 Draw a single green letter "g", at the center of the input video.
4265 The glyph baseline is placed at half screen height.
4267 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
4271 Show text for 1 second every 3 seconds:
4273 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
4277 Use fontconfig to set the font. Note that the colons need to be escaped.
4279 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
4283 Print the date of a real-time encoding (see strftime(3)):
4285 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
4289 Show text fading in and out (appearing/disappearing):
4292 DS=1.0 # display start
4293 DE=10.0 # display end
4294 FID=1.5 # fade in duration
4295 FOD=5 # fade out duration
4296 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 @}"
4301 For more information about libfreetype, check:
4302 @url{http://www.freetype.org/}.
4304 For more information about fontconfig, check:
4305 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
4307 For more information about libfribidi, check:
4308 @url{http://fribidi.org/}.
4312 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
4314 The filter accepts the following options:
4319 Set low and high threshold values used by the Canny thresholding
4322 The high threshold selects the "strong" edge pixels, which are then
4323 connected through 8-connectivity with the "weak" edge pixels selected
4324 by the low threshold.
4326 @var{low} and @var{high} threshold values must be chosen in the range
4327 [0,1], and @var{low} should be lesser or equal to @var{high}.
4329 Default value for @var{low} is @code{20/255}, and default value for @var{high}
4333 Define the drawing mode.
4337 Draw white/gray wires on black background.
4340 Mix the colors to create a paint/cartoon effect.
4343 Default value is @var{wires}.
4346 @subsection Examples
4350 Standard edge detection with custom values for the hysteresis thresholding:
4352 edgedetect=low=0.1:high=0.4
4356 Painting effect without thresholding:
4358 edgedetect=mode=colormix:high=0
4363 Set brightness, contrast, saturation and approximate gamma adjustment.
4365 The filter accepts the following options:
4369 Set the contrast value. It accepts a float value in range @code{-2.0} to
4370 @code{2.0}. The default value is @code{0.0}.
4373 Set the brightness value. It accepts a float value in range @code{-1.0} to
4374 @code{1.0}. The default value is @code{0.0}.
4377 Set the saturation value. It accepts a float value in range @code{0.0} to
4378 @code{3.0}. The default value is @code{1.0}.
4381 Set the gamma value. It accepts a float value in range @code{0.1} to @code{10.0}.
4382 The default value is @code{1.0}.
4385 Set the gamma value for red. It accepts a float value in range
4386 @code{0.1} to @code{10.0}. The default value is @code{1.0}.
4389 Set the gamma value for green. It accepts a float value in range
4390 @code{0.1} to @code{10.0}. The default value is @code{1.0}.
4393 Set the gamma value for blue. It accepts a float value in range
4394 @code{0.1} to @code{10.0}. The default value is @code{1.0}.
4397 Can be used to reduce the effect of a high gamma value on bright image areas,
4398 e.g. keep them from getting overamplified and just plain white. It accepts a
4399 float value in range @code{0.0} to @code{1.0}.A value of @code{0.0} turns the
4400 gamma correction all the way down while @code{1.0} leaves it at its full strength.
4401 Default is @code{1.0}.
4405 @subsection Commands
4406 The filter supports the following commands:
4410 Set the contrast expression.
4413 Set the brightness expression.
4416 Set the saturation expression.
4419 Set the gamma expression.
4422 Set the gamma_r expression.
4425 Set gamma_g expression.
4428 Set gamma_b expression.
4431 Set gamma_weight expression.
4433 The command accepts the same syntax of the corresponding option.
4435 If the specified expression is not valid, it is kept at its current
4440 @section extractplanes
4442 Extract color channel components from input video stream into
4443 separate grayscale video streams.
4445 The filter accepts the following option:
4449 Set plane(s) to extract.
4451 Available values for planes are:
4462 Choosing planes not available in the input will result in an error.
4463 That means you cannot select @code{r}, @code{g}, @code{b} planes
4464 with @code{y}, @code{u}, @code{v} planes at same time.
4467 @subsection Examples
4471 Extract luma, u and v color channel component from input video frame
4472 into 3 grayscale outputs:
4474 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
4480 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4482 For each input image, the filter will compute the optimal mapping from
4483 the input to the output given the codebook length, that is the number
4484 of distinct output colors.
4486 This filter accepts the following options.
4489 @item codebook_length, l
4490 Set codebook length. The value must be a positive integer, and
4491 represents the number of distinct output colors. Default value is 256.
4494 Set the maximum number of iterations to apply for computing the optimal
4495 mapping. The higher the value the better the result and the higher the
4496 computation time. Default value is 1.
4499 Set a random seed, must be an integer included between 0 and
4500 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4501 will try to use a good random seed on a best effort basis.
4506 Apply a fade-in/out effect to the input video.
4508 It accepts the following parameters:
4512 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4514 Default is @code{in}.
4516 @item start_frame, s
4517 Specify the number of the frame to start applying the fade
4518 effect at. Default is 0.
4521 The number of frames that the fade effect lasts. At the end of the
4522 fade-in effect, the output video will have the same intensity as the input video.
4523 At the end of the fade-out transition, the output video will be filled with the
4524 selected @option{color}.
4528 If set to 1, fade only alpha channel, if one exists on the input.
4531 @item start_time, st
4532 Specify the timestamp (in seconds) of the frame to start to apply the fade
4533 effect. If both start_frame and start_time are specified, the fade will start at
4534 whichever comes last. Default is 0.
4537 The number of seconds for which the fade effect has to last. At the end of the
4538 fade-in effect the output video will have the same intensity as the input video,
4539 at the end of the fade-out transition the output video will be filled with the
4540 selected @option{color}.
4541 If both duration and nb_frames are specified, duration is used. Default is 0.
4544 Specify the color of the fade. Default is "black".
4547 @subsection Examples
4551 Fade in the first 30 frames of video:
4556 The command above is equivalent to:
4562 Fade out the last 45 frames of a 200-frame video:
4565 fade=type=out:start_frame=155:nb_frames=45
4569 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4571 fade=in:0:25, fade=out:975:25
4575 Make the first 5 frames yellow, then fade in from frame 5-24:
4577 fade=in:5:20:color=yellow
4581 Fade in alpha over first 25 frames of video:
4583 fade=in:0:25:alpha=1
4587 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4589 fade=t=in:st=5.5:d=0.5
4595 Apply arbitrary expressions to samples in frequency domain
4599 Adjust the dc value (gain) of the luma plane of the image. The filter
4600 accepts an integer value in range @code{0} to @code{1000}. The default
4601 value is set to @code{0}.
4604 Adjust the dc value (gain) of the 1st chroma plane of the image. The
4605 filter accepts an integer value in range @code{0} to @code{1000}. The
4606 default value is set to @code{0}.
4609 Adjust the dc value (gain) of the 2nd chroma plane of the image. The
4610 filter accepts an integer value in range @code{0} to @code{1000}. The
4611 default value is set to @code{0}.
4614 Set the frequency domain weight expression for the luma plane.
4617 Set the frequency domain weight expression for the 1st chroma plane.
4620 Set the frequency domain weight expression for the 2nd chroma plane.
4622 The filter accepts the following variables:
4625 The coordinates of the current sample.
4629 The width and height of the image.
4632 @subsection Examples
4638 fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
4644 fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
4650 fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
4657 Extract a single field from an interlaced image using stride
4658 arithmetic to avoid wasting CPU time. The output frames are marked as
4661 The filter accepts the following options:
4665 Specify whether to extract the top (if the value is @code{0} or
4666 @code{top}) or the bottom field (if the value is @code{1} or
4672 Field matching filter for inverse telecine. It is meant to reconstruct the
4673 progressive frames from a telecined stream. The filter does not drop duplicated
4674 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4675 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4677 The separation of the field matching and the decimation is notably motivated by
4678 the possibility of inserting a de-interlacing filter fallback between the two.
4679 If the source has mixed telecined and real interlaced content,
4680 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4681 But these remaining combed frames will be marked as interlaced, and thus can be
4682 de-interlaced by a later filter such as @ref{yadif} before decimation.
4684 In addition to the various configuration options, @code{fieldmatch} can take an
4685 optional second stream, activated through the @option{ppsrc} option. If
4686 enabled, the frames reconstruction will be based on the fields and frames from
4687 this second stream. This allows the first input to be pre-processed in order to
4688 help the various algorithms of the filter, while keeping the output lossless
4689 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4690 or brightness/contrast adjustments can help.
4692 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4693 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4694 which @code{fieldmatch} is based on. While the semantic and usage are very
4695 close, some behaviour and options names can differ.
4697 The @ref{decimate} filter currently only works for constant frame rate input.
4698 Do not use @code{fieldmatch} and @ref{decimate} if your input has mixed
4699 telecined and progressive content with changing framerate.
4701 The filter accepts the following options:
4705 Specify the assumed field order of the input stream. Available values are:
4709 Auto detect parity (use FFmpeg's internal parity value).
4711 Assume bottom field first.
4713 Assume top field first.
4716 Note that it is sometimes recommended not to trust the parity announced by the
4719 Default value is @var{auto}.
4722 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4723 sense that it won't risk creating jerkiness due to duplicate frames when
4724 possible, but if there are bad edits or blended fields it will end up
4725 outputting combed frames when a good match might actually exist. On the other
4726 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4727 but will almost always find a good frame if there is one. The other values are
4728 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4729 jerkiness and creating duplicate frames versus finding good matches in sections
4730 with bad edits, orphaned fields, blended fields, etc.
4732 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4734 Available values are:
4738 2-way matching (p/c)
4740 2-way matching, and trying 3rd match if still combed (p/c + n)
4742 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4744 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4745 still combed (p/c + n + u/b)
4747 3-way matching (p/c/n)
4749 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4750 detected as combed (p/c/n + u/b)
4753 The parenthesis at the end indicate the matches that would be used for that
4754 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4757 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4760 Default value is @var{pc_n}.
4763 Mark the main input stream as a pre-processed input, and enable the secondary
4764 input stream as the clean source to pick the fields from. See the filter
4765 introduction for more details. It is similar to the @option{clip2} feature from
4768 Default value is @code{0} (disabled).
4771 Set the field to match from. It is recommended to set this to the same value as
4772 @option{order} unless you experience matching failures with that setting. In
4773 certain circumstances changing the field that is used to match from can have a
4774 large impact on matching performance. Available values are:
4778 Automatic (same value as @option{order}).
4780 Match from the bottom field.
4782 Match from the top field.
4785 Default value is @var{auto}.
4788 Set whether or not chroma is included during the match comparisons. In most
4789 cases it is recommended to leave this enabled. You should set this to @code{0}
4790 only if your clip has bad chroma problems such as heavy rainbowing or other
4791 artifacts. Setting this to @code{0} could also be used to speed things up at
4792 the cost of some accuracy.
4794 Default value is @code{1}.
4798 These define an exclusion band which excludes the lines between @option{y0} and
4799 @option{y1} from being included in the field matching decision. An exclusion
4800 band can be used to ignore subtitles, a logo, or other things that may
4801 interfere with the matching. @option{y0} sets the starting scan line and
4802 @option{y1} sets the ending line; all lines in between @option{y0} and
4803 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4804 @option{y0} and @option{y1} to the same value will disable the feature.
4805 @option{y0} and @option{y1} defaults to @code{0}.
4808 Set the scene change detection threshold as a percentage of maximum change on
4809 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4810 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4811 @option{scthresh} is @code{[0.0, 100.0]}.
4813 Default value is @code{12.0}.
4816 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4817 account the combed scores of matches when deciding what match to use as the
4818 final match. Available values are:
4822 No final matching based on combed scores.
4824 Combed scores are only used when a scene change is detected.
4826 Use combed scores all the time.
4829 Default is @var{sc}.
4832 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4833 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4834 Available values are:
4838 No forced calculation.
4840 Force p/c/n calculations.
4842 Force p/c/n/u/b calculations.
4845 Default value is @var{none}.
4848 This is the area combing threshold used for combed frame detection. This
4849 essentially controls how "strong" or "visible" combing must be to be detected.
4850 Larger values mean combing must be more visible and smaller values mean combing
4851 can be less visible or strong and still be detected. Valid settings are from
4852 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4853 be detected as combed). This is basically a pixel difference value. A good
4854 range is @code{[8, 12]}.
4856 Default value is @code{9}.
4859 Sets whether or not chroma is considered in the combed frame decision. Only
4860 disable this if your source has chroma problems (rainbowing, etc.) that are
4861 causing problems for the combed frame detection with chroma enabled. Actually,
4862 using @option{chroma}=@var{0} is usually more reliable, except for the case
4863 where there is chroma only combing in the source.
4865 Default value is @code{0}.
4869 Respectively set the x-axis and y-axis size of the window used during combed
4870 frame detection. This has to do with the size of the area in which
4871 @option{combpel} pixels are required to be detected as combed for a frame to be
4872 declared combed. See the @option{combpel} parameter description for more info.
4873 Possible values are any number that is a power of 2 starting at 4 and going up
4876 Default value is @code{16}.
4879 The number of combed pixels inside any of the @option{blocky} by
4880 @option{blockx} size blocks on the frame for the frame to be detected as
4881 combed. While @option{cthresh} controls how "visible" the combing must be, this
4882 setting controls "how much" combing there must be in any localized area (a
4883 window defined by the @option{blockx} and @option{blocky} settings) on the
4884 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4885 which point no frames will ever be detected as combed). This setting is known
4886 as @option{MI} in TFM/VFM vocabulary.
4888 Default value is @code{80}.
4891 @anchor{p/c/n/u/b meaning}
4892 @subsection p/c/n/u/b meaning
4894 @subsubsection p/c/n
4896 We assume the following telecined stream:
4899 Top fields: 1 2 2 3 4
4900 Bottom fields: 1 2 3 4 4
4903 The numbers correspond to the progressive frame the fields relate to. Here, the
4904 first two frames are progressive, the 3rd and 4th are combed, and so on.
4906 When @code{fieldmatch} is configured to run a matching from bottom
4907 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4912 B 1 2 3 4 4 <-- matching reference
4921 As a result of the field matching, we can see that some frames get duplicated.
4922 To perform a complete inverse telecine, you need to rely on a decimation filter
4923 after this operation. See for instance the @ref{decimate} filter.
4925 The same operation now matching from top fields (@option{field}=@var{top})
4930 T 1 2 2 3 4 <-- matching reference
4940 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4941 basically, they refer to the frame and field of the opposite parity:
4944 @item @var{p} matches the field of the opposite parity in the previous frame
4945 @item @var{c} matches the field of the opposite parity in the current frame
4946 @item @var{n} matches the field of the opposite parity in the next frame
4951 The @var{u} and @var{b} matching are a bit special in the sense that they match
4952 from the opposite parity flag. In the following examples, we assume that we are
4953 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4954 'x' is placed above and below each matched fields.
4956 With bottom matching (@option{field}=@var{bottom}):
4961 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4962 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4970 With top matching (@option{field}=@var{top}):
4975 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4976 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4984 @subsection Examples
4986 Simple IVTC of a top field first telecined stream:
4988 fieldmatch=order=tff:combmatch=none, decimate
4991 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4993 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4998 Transform the field order of the input video.
5000 It accepts the following parameters:
5005 The output field order. Valid values are @var{tff} for top field first or @var{bff}
5006 for bottom field first.
5009 The default value is @samp{tff}.
5011 The transformation is done by shifting the picture content up or down
5012 by one line, and filling the remaining line with appropriate picture content.
5013 This method is consistent with most broadcast field order converters.
5015 If the input video is not flagged as being interlaced, or it is already
5016 flagged as being of the required output field order, then this filter does
5017 not alter the incoming video.
5019 It is very useful when converting to or from PAL DV material,
5020 which is bottom field first.
5024 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
5029 Buffer input images and send them when they are requested.
5031 It is mainly useful when auto-inserted by the libavfilter
5034 It does not take parameters.
5039 Convert the input video to one of the specified pixel formats.
5040 Libavfilter will try to pick one that is suitable as input to
5043 It accepts the following parameters:
5047 A '|'-separated list of pixel format names, such as
5048 "pix_fmts=yuv420p|monow|rgb24".
5052 @subsection Examples
5056 Convert the input video to the @var{yuv420p} format
5058 format=pix_fmts=yuv420p
5061 Convert the input video to any of the formats in the list
5063 format=pix_fmts=yuv420p|yuv444p|yuv410p
5070 Convert the video to specified constant frame rate by duplicating or dropping
5071 frames as necessary.
5073 It accepts the following parameters:
5077 The desired output frame rate. The default is @code{25}.
5082 Possible values are:
5085 zero round towards 0
5089 round towards -infinity
5091 round towards +infinity
5095 The default is @code{near}.
5098 Assume the first PTS should be the given value, in seconds. This allows for
5099 padding/trimming at the start of stream. By default, no assumption is made
5100 about the first frame's expected PTS, so no padding or trimming is done.
5101 For example, this could be set to 0 to pad the beginning with duplicates of
5102 the first frame if a video stream starts after the audio stream or to trim any
5103 frames with a negative PTS.
5107 Alternatively, the options can be specified as a flat string:
5108 @var{fps}[:@var{round}].
5110 See also the @ref{setpts} filter.
5112 @subsection Examples
5116 A typical usage in order to set the fps to 25:
5122 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
5124 fps=fps=film:round=near
5130 Pack two different video streams into a stereoscopic video, setting proper
5131 metadata on supported codecs. The two views should have the same size and
5132 framerate and processing will stop when the shorter video ends. Please note
5133 that you may conveniently adjust view properties with the @ref{scale} and
5136 It accepts the following parameters:
5140 The desired packing format. Supported values are:
5145 The views are next to each other (default).
5148 The views are on top of each other.
5151 The views are packed by line.
5154 The views are packed by column.
5157 The views are temporally interleaved.
5166 # Convert left and right views into a frame-sequential video
5167 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
5169 # Convert views into a side-by-side video with the same output resolution as the input
5170 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
5175 Select one frame every N-th frame.
5177 This filter accepts the following option:
5180 Select frame after every @code{step} frames.
5181 Allowed values are positive integers higher than 0. Default value is @code{1}.
5187 Apply a frei0r effect to the input video.
5189 To enable the compilation of this filter, you need to install the frei0r
5190 header and configure FFmpeg with @code{--enable-frei0r}.
5192 It accepts the following parameters:
5197 The name of the frei0r effect to load. If the environment variable
5198 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
5199 directories specified by the colon-separated list in @env{FREIOR_PATH}.
5200 Otherwise, the standard frei0r paths are searched, in this order:
5201 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
5202 @file{/usr/lib/frei0r-1/}.
5205 A '|'-separated list of parameters to pass to the frei0r effect.
5209 A frei0r effect parameter can be a boolean (its value is either
5210 "y" or "n"), a double, a color (specified as
5211 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
5212 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
5213 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
5214 @var{X} and @var{Y} are floating point numbers) and/or a string.
5216 The number and types of parameters depend on the loaded effect. If an
5217 effect parameter is not specified, the default value is set.
5219 @subsection Examples
5223 Apply the distort0r effect, setting the first two double parameters:
5225 frei0r=filter_name=distort0r:filter_params=0.5|0.01
5229 Apply the colordistance effect, taking a color as the first parameter:
5231 frei0r=colordistance:0.2/0.3/0.4
5232 frei0r=colordistance:violet
5233 frei0r=colordistance:0x112233
5237 Apply the perspective effect, specifying the top left and top right image
5240 frei0r=perspective:0.2/0.2|0.8/0.2
5244 For more information, see
5245 @url{http://frei0r.dyne.org}
5249 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
5251 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
5252 processing filter, one of them is performed once per block, not per pixel.
5253 This allows for much higher speed.
5255 The filter accepts the following options:
5259 Set quality. This option defines the number of levels for averaging. It accepts
5260 an integer in the range 4-5. Default value is @code{4}.
5263 Force a constant quantization parameter. It accepts an integer in range 0-63.
5264 If not set, the filter will use the QP from the video stream (if available).
5267 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
5268 more details but also more artifacts, while higher values make the image smoother
5269 but also blurrier. Default value is @code{0} − PSNR optimal.
5272 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
5273 option may cause flicker since the B-Frames have often larger QP. Default is
5274 @code{0} (not enabled).
5280 The filter accepts the following options:
5284 Set the luminance expression.
5286 Set the chrominance blue expression.
5288 Set the chrominance red expression.
5290 Set the alpha expression.
5292 Set the red expression.
5294 Set the green expression.
5296 Set the blue expression.
5299 The colorspace is selected according to the specified options. If one
5300 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
5301 options is specified, the filter will automatically select a YCbCr
5302 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
5303 @option{blue_expr} options is specified, it will select an RGB
5306 If one of the chrominance expression is not defined, it falls back on the other
5307 one. If no alpha expression is specified it will evaluate to opaque value.
5308 If none of chrominance expressions are specified, they will evaluate
5309 to the luminance expression.
5311 The expressions can use the following variables and functions:
5315 The sequential number of the filtered frame, starting from @code{0}.
5319 The coordinates of the current sample.
5323 The width and height of the image.
5327 Width and height scale depending on the currently filtered plane. It is the
5328 ratio between the corresponding luma plane number of pixels and the current
5329 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
5330 @code{0.5,0.5} for chroma planes.
5333 Time of the current frame, expressed in seconds.
5336 Return the value of the pixel at location (@var{x},@var{y}) of the current
5340 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
5344 Return the value of the pixel at location (@var{x},@var{y}) of the
5345 blue-difference chroma plane. Return 0 if there is no such plane.
5348 Return the value of the pixel at location (@var{x},@var{y}) of the
5349 red-difference chroma plane. Return 0 if there is no such plane.
5354 Return the value of the pixel at location (@var{x},@var{y}) of the
5355 red/green/blue component. Return 0 if there is no such component.
5358 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
5359 plane. Return 0 if there is no such plane.
5362 For functions, if @var{x} and @var{y} are outside the area, the value will be
5363 automatically clipped to the closer edge.
5365 @subsection Examples
5369 Flip the image horizontally:
5375 Generate a bidimensional sine wave, with angle @code{PI/3} and a
5376 wavelength of 100 pixels:
5378 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
5382 Generate a fancy enigmatic moving light:
5384 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
5388 Generate a quick emboss effect:
5390 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
5394 Modify RGB components depending on pixel position:
5396 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
5400 Create a radial gradient that is the same size as the input (also see
5401 the @ref{vignette} filter):
5403 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
5407 Create a linear gradient to use as a mask for another filter, then
5408 compose with @ref{overlay}. In this example the video will gradually
5409 become more blurry from the top to the bottom of the y-axis as defined
5410 by the linear gradient:
5412 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
5418 Fix the banding artifacts that are sometimes introduced into nearly flat
5419 regions by truncation to 8bit color depth.
5420 Interpolate the gradients that should go where the bands are, and
5423 It is designed for playback only. Do not use it prior to
5424 lossy compression, because compression tends to lose the dither and
5425 bring back the bands.
5427 It accepts the following parameters:
5432 The maximum amount by which the filter will change any one pixel. This is also
5433 the threshold for detecting nearly flat regions. Acceptable values range from
5434 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
5438 The neighborhood to fit the gradient to. A larger radius makes for smoother
5439 gradients, but also prevents the filter from modifying the pixels near detailed
5440 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
5441 values will be clipped to the valid range.
5445 Alternatively, the options can be specified as a flat string:
5446 @var{strength}[:@var{radius}]
5448 @subsection Examples
5452 Apply the filter with a @code{3.5} strength and radius of @code{8}:
5458 Specify radius, omitting the strength (which will fall-back to the default
5469 Apply a Hald CLUT to a video stream.
5471 First input is the video stream to process, and second one is the Hald CLUT.
5472 The Hald CLUT input can be a simple picture or a complete video stream.
5474 The filter accepts the following options:
5478 Force termination when the shortest input terminates. Default is @code{0}.
5480 Continue applying the last CLUT after the end of the stream. A value of
5481 @code{0} disable the filter after the last frame of the CLUT is reached.
5482 Default is @code{1}.
5485 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
5486 filters share the same internals).
5488 More information about the Hald CLUT can be found on Eskil Steenberg's website
5489 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
5491 @subsection Workflow examples
5493 @subsubsection Hald CLUT video stream
5495 Generate an identity Hald CLUT stream altered with various effects:
5497 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
5500 Note: make sure you use a lossless codec.
5502 Then use it with @code{haldclut} to apply it on some random stream:
5504 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
5507 The Hald CLUT will be applied to the 10 first seconds (duration of
5508 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
5509 to the remaining frames of the @code{mandelbrot} stream.
5511 @subsubsection Hald CLUT with preview
5513 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
5514 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
5515 biggest possible square starting at the top left of the picture. The remaining
5516 padding pixels (bottom or right) will be ignored. This area can be used to add
5517 a preview of the Hald CLUT.
5519 Typically, the following generated Hald CLUT will be supported by the
5520 @code{haldclut} filter:
5523 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
5524 pad=iw+320 [padded_clut];
5525 smptebars=s=320x256, split [a][b];
5526 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
5527 [main][b] overlay=W-320" -frames:v 1 clut.png
5530 It contains the original and a preview of the effect of the CLUT: SMPTE color
5531 bars are displayed on the right-top, and below the same color bars processed by
5534 Then, the effect of this Hald CLUT can be visualized with:
5536 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
5541 Flip the input video horizontally.
5543 For example, to horizontally flip the input video with @command{ffmpeg}:
5545 ffmpeg -i in.avi -vf "hflip" out.avi
5549 This filter applies a global color histogram equalization on a
5552 It can be used to correct video that has a compressed range of pixel
5553 intensities. The filter redistributes the pixel intensities to
5554 equalize their distribution across the intensity range. It may be
5555 viewed as an "automatically adjusting contrast filter". This filter is
5556 useful only for correcting degraded or poorly captured source
5559 The filter accepts the following options:
5563 Determine the amount of equalization to be applied. As the strength
5564 is reduced, the distribution of pixel intensities more-and-more
5565 approaches that of the input frame. The value must be a float number
5566 in the range [0,1] and defaults to 0.200.
5569 Set the maximum intensity that can generated and scale the output
5570 values appropriately. The strength should be set as desired and then
5571 the intensity can be limited if needed to avoid washing-out. The value
5572 must be a float number in the range [0,1] and defaults to 0.210.
5575 Set the antibanding level. If enabled the filter will randomly vary
5576 the luminance of output pixels by a small amount to avoid banding of
5577 the histogram. Possible values are @code{none}, @code{weak} or
5578 @code{strong}. It defaults to @code{none}.
5583 Compute and draw a color distribution histogram for the input video.
5585 The computed histogram is a representation of the color component
5586 distribution in an image.
5588 The filter accepts the following options:
5594 It accepts the following values:
5597 Standard histogram that displays the color components distribution in an
5598 image. Displays color graph for each color component. Shows distribution of
5599 the Y, U, V, A or R, G, B components, depending on input format, in the
5600 current frame. Below each graph a color component scale meter is shown.
5603 Displays chroma values (U/V color placement) in a two dimensional
5604 graph (which is called a vectorscope). The brighter a pixel in the
5605 vectorscope, the more pixels of the input frame correspond to that pixel
5606 (i.e., more pixels have this chroma value). The V component is displayed on
5607 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5608 side being V = 255. The U component is displayed on the vertical (Y) axis,
5609 with the top representing U = 0 and the bottom representing U = 255.
5611 The position of a white pixel in the graph corresponds to the chroma value of
5612 a pixel of the input clip. The graph can therefore be used to read the hue
5613 (color flavor) and the saturation (the dominance of the hue in the color). As
5614 the hue of a color changes, it moves around the square. At the center of the
5615 square the saturation is zero, which means that the corresponding pixel has no
5616 color. If the amount of a specific color is increased (while leaving the other
5617 colors unchanged) the saturation increases, and the indicator moves towards
5618 the edge of the square.
5621 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5625 Per row/column color component graph. In row mode, the graph on the left side
5626 represents color component value 0 and the right side represents value = 255.
5627 In column mode, the top side represents color component value = 0 and bottom
5628 side represents value = 255.
5630 Default value is @code{levels}.
5633 Set height of level in @code{levels}. Default value is @code{200}.
5634 Allowed range is [50, 2048].
5637 Set height of color scale in @code{levels}. Default value is @code{12}.
5638 Allowed range is [0, 40].
5641 Set step for @code{waveform} mode. Smaller values are useful to find out how
5642 many values of the same luminance are distributed across input rows/columns.
5643 Default value is @code{10}. Allowed range is [1, 255].
5646 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5647 Default is @code{row}.
5649 @item waveform_mirror
5650 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5651 means mirrored. In mirrored mode, higher values will be represented on the left
5652 side for @code{row} mode and at the top for @code{column} mode. Default is
5653 @code{0} (unmirrored).
5656 Set display mode for @code{waveform} and @code{levels}.
5657 It accepts the following values:
5660 Display separate graph for the color components side by side in
5661 @code{row} waveform mode or one below the other in @code{column} waveform mode
5662 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5663 per color component graphs are placed below each other.
5665 Using this display mode in @code{waveform} histogram mode makes it easy to
5666 spot color casts in the highlights and shadows of an image, by comparing the
5667 contours of the top and the bottom graphs of each waveform. Since whites,
5668 grays, and blacks are characterized by exactly equal amounts of red, green,
5669 and blue, neutral areas of the picture should display three waveforms of
5670 roughly equal width/height. If not, the correction is easy to perform by
5671 making level adjustments the three waveforms.
5674 Presents information identical to that in the @code{parade}, except
5675 that the graphs representing color components are superimposed directly
5678 This display mode in @code{waveform} histogram mode makes it easier to spot
5679 relative differences or similarities in overlapping areas of the color
5680 components that are supposed to be identical, such as neutral whites, grays,
5683 Default is @code{parade}.
5686 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5687 Default is @code{linear}.
5690 @subsection Examples
5695 Calculate and draw histogram:
5697 ffplay -i input -vf histogram
5705 This is a high precision/quality 3d denoise filter. It aims to reduce
5706 image noise, producing smooth images and making still images really
5707 still. It should enhance compressibility.
5709 It accepts the following optional parameters:
5713 A non-negative floating point number which specifies spatial luma strength.
5716 @item chroma_spatial
5717 A non-negative floating point number which specifies spatial chroma strength.
5718 It defaults to 3.0*@var{luma_spatial}/4.0.
5721 A floating point number which specifies luma temporal strength. It defaults to
5722 6.0*@var{luma_spatial}/4.0.
5725 A floating point number which specifies chroma temporal strength. It defaults to
5726 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5731 Apply a high-quality magnification filter designed for pixel art. This filter
5732 was originally created by Maxim Stepin.
5734 It accepts the following option:
5738 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
5739 @code{hq3x} and @code{4} for @code{hq4x}.
5740 Default is @code{3}.
5745 Modify the hue and/or the saturation of the input.
5747 It accepts the following parameters:
5751 Specify the hue angle as a number of degrees. It accepts an expression,
5752 and defaults to "0".
5755 Specify the saturation in the [-10,10] range. It accepts an expression and
5759 Specify the hue angle as a number of radians. It accepts an
5760 expression, and defaults to "0".
5763 Specify the brightness in the [-10,10] range. It accepts an expression and
5767 @option{h} and @option{H} are mutually exclusive, and can't be
5768 specified at the same time.
5770 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5771 expressions containing the following constants:
5775 frame count of the input frame starting from 0
5778 presentation timestamp of the input frame expressed in time base units
5781 frame rate of the input video, NAN if the input frame rate is unknown
5784 timestamp expressed in seconds, NAN if the input timestamp is unknown
5787 time base of the input video
5790 @subsection Examples
5794 Set the hue to 90 degrees and the saturation to 1.0:
5800 Same command but expressing the hue in radians:
5806 Rotate hue and make the saturation swing between 0
5807 and 2 over a period of 1 second:
5809 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5813 Apply a 3 seconds saturation fade-in effect starting at 0:
5818 The general fade-in expression can be written as:
5820 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5824 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5826 hue="s=max(0\, min(1\, (8-t)/3))"
5829 The general fade-out expression can be written as:
5831 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5836 @subsection Commands
5838 This filter supports the following commands:
5844 Modify the hue and/or the saturation and/or brightness of the input video.
5845 The command accepts the same syntax of the corresponding option.
5847 If the specified expression is not valid, it is kept at its current
5853 Detect video interlacing type.
5855 This filter tries to detect if the input frames as interlaced, progressive,
5856 top or bottom field first. It will also try and detect fields that are
5857 repeated between adjacent frames (a sign of telecine).
5859 Single frame detection considers only immediately adjacent frames when classifying each frame.
5860 Multiple frame detection incorporates the classification history of previous frames.
5862 The filter will log these metadata values:
5865 @item single.current_frame
5866 Detected type of current frame using single-frame detection. One of:
5867 ``tff'' (top field first), ``bff'' (bottom field first),
5868 ``progressive'', or ``undetermined''
5871 Cumulative number of frames detected as top field first using single-frame detection.
5874 Cumulative number of frames detected as top field first using multiple-frame detection.
5877 Cumulative number of frames detected as bottom field first using single-frame detection.
5879 @item multiple.current_frame
5880 Detected type of current frame using multiple-frame detection. One of:
5881 ``tff'' (top field first), ``bff'' (bottom field first),
5882 ``progressive'', or ``undetermined''
5885 Cumulative number of frames detected as bottom field first using multiple-frame detection.
5887 @item single.progressive
5888 Cumulative number of frames detected as progressive using single-frame detection.
5890 @item multiple.progressive
5891 Cumulative number of frames detected as progressive using multiple-frame detection.
5893 @item single.undetermined
5894 Cumulative number of frames that could not be classified using single-frame detection.
5896 @item multiple.undetermined
5897 Cumulative number of frames that could not be classified using multiple-frame detection.
5899 @item repeated.current_frame
5900 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
5902 @item repeated.neither
5903 Cumulative number of frames with no repeated field.
5906 Cumulative number of frames with the top field repeated from the previous frame's top field.
5908 @item repeated.bottom
5909 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
5912 The filter accepts the following options:
5916 Set interlacing threshold.
5918 Set progressive threshold.
5920 Threshold for repeated field detection.
5922 Number of frames after which a given frame's contribution to the
5923 statistics is halved (i.e., it contributes only 0.5 to it's
5924 classification). The default of 0 means that all frames seen are given
5925 full weight of 1.0 forever.
5926 @item analyze_interlaced_flag
5927 When this is not 0 then idet will use the specified number of frames to determine
5928 if the interlaced flag is accurate, it will not count undetermined frames.
5929 If the flag is found to be accurate it will be used without any further
5930 computations, if it is found to be inaccuarte it will be cleared without any
5931 further computations. This allows inserting the idet filter as a low computational
5932 method to clean up the interlaced flag
5937 Deinterleave or interleave fields.
5939 This filter allows one to process interlaced images fields without
5940 deinterlacing them. Deinterleaving splits the input frame into 2
5941 fields (so called half pictures). Odd lines are moved to the top
5942 half of the output image, even lines to the bottom half.
5943 You can process (filter) them independently and then re-interleave them.
5945 The filter accepts the following options:
5949 @item chroma_mode, c
5951 Available values for @var{luma_mode}, @var{chroma_mode} and
5952 @var{alpha_mode} are:
5958 @item deinterleave, d
5959 Deinterleave fields, placing one above the other.
5962 Interleave fields. Reverse the effect of deinterleaving.
5964 Default value is @code{none}.
5967 @item chroma_swap, cs
5968 @item alpha_swap, as
5969 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5974 Simple interlacing filter from progressive contents. This interleaves upper (or
5975 lower) lines from odd frames with lower (or upper) lines from even frames,
5976 halving the frame rate and preserving image height.
5979 Original Original New Frame
5980 Frame 'j' Frame 'j+1' (tff)
5981 ========== =========== ==================
5982 Line 0 --------------------> Frame 'j' Line 0
5983 Line 1 Line 1 ----> Frame 'j+1' Line 1
5984 Line 2 ---------------------> Frame 'j' Line 2
5985 Line 3 Line 3 ----> Frame 'j+1' Line 3
5987 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5990 It accepts the following optional parameters:
5994 This determines whether the interlaced frame is taken from the even
5995 (tff - default) or odd (bff) lines of the progressive frame.
5998 Enable (default) or disable the vertical lowpass filter to avoid twitter
5999 interlacing and reduce moire patterns.
6004 Deinterlace input video by applying Donald Graft's adaptive kernel
6005 deinterling. Work on interlaced parts of a video to produce
6008 The description of the accepted parameters follows.
6012 Set the threshold which affects the filter's tolerance when
6013 determining if a pixel line must be processed. It must be an integer
6014 in the range [0,255] and defaults to 10. A value of 0 will result in
6015 applying the process on every pixels.
6018 Paint pixels exceeding the threshold value to white if set to 1.
6022 Set the fields order. Swap fields if set to 1, leave fields alone if
6026 Enable additional sharpening if set to 1. Default is 0.
6029 Enable twoway sharpening if set to 1. Default is 0.
6032 @subsection Examples
6036 Apply default values:
6038 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
6042 Enable additional sharpening:
6048 Paint processed pixels in white:
6054 @section lenscorrection
6056 Correct radial lens distortion
6058 This filter can be used to correct for radial distortion as can result from the use
6059 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
6060 one can use tools available for example as part of opencv or simply trial-and-error.
6061 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
6062 and extract the k1 and k2 coefficients from the resulting matrix.
6064 Note that effectively the same filter is available in the open-source tools Krita and
6065 Digikam from the KDE project.
6067 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
6068 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
6069 brightness distribution, so you may want to use both filters together in certain
6070 cases, though you will have to take care of ordering, i.e. whether vignetting should
6071 be applied before or after lens correction.
6075 The filter accepts the following options:
6079 Relative x-coordinate of the focal point of the image, and thereby the center of the
6080 distortion. This value has a range [0,1] and is expressed as fractions of the image
6083 Relative y-coordinate of the focal point of the image, and thereby the center of the
6084 distortion. This value has a range [0,1] and is expressed as fractions of the image
6087 Coefficient of the quadratic correction term. 0.5 means no correction.
6089 Coefficient of the double quadratic correction term. 0.5 means no correction.
6092 The formula that generates the correction is:
6094 @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)
6096 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
6097 distances from the focal point in the source and target images, respectively.
6102 Apply a 3D LUT to an input video.
6104 The filter accepts the following options:
6108 Set the 3D LUT file name.
6110 Currently supported formats:
6122 Select interpolation mode.
6124 Available values are:
6128 Use values from the nearest defined point.
6130 Interpolate values using the 8 points defining a cube.
6132 Interpolate values using a tetrahedron.
6136 @section lut, lutrgb, lutyuv
6138 Compute a look-up table for binding each pixel component input value
6139 to an output value, and apply it to the input video.
6141 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
6142 to an RGB input video.
6144 These filters accept the following parameters:
6147 set first pixel component expression
6149 set second pixel component expression
6151 set third pixel component expression
6153 set fourth pixel component expression, corresponds to the alpha component
6156 set red component expression
6158 set green component expression
6160 set blue component expression
6162 alpha component expression
6165 set Y/luminance component expression
6167 set U/Cb component expression
6169 set V/Cr component expression
6172 Each of them specifies the expression to use for computing the lookup table for
6173 the corresponding pixel component values.
6175 The exact component associated to each of the @var{c*} options depends on the
6178 The @var{lut} filter requires either YUV or RGB pixel formats in input,
6179 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
6181 The expressions can contain the following constants and functions:
6186 The input width and height.
6189 The input value for the pixel component.
6192 The input value, clipped to the @var{minval}-@var{maxval} range.
6195 The maximum value for the pixel component.
6198 The minimum value for the pixel component.
6201 The negated value for the pixel component value, clipped to the
6202 @var{minval}-@var{maxval} range; it corresponds to the expression
6203 "maxval-clipval+minval".
6206 The computed value in @var{val}, clipped to the
6207 @var{minval}-@var{maxval} range.
6209 @item gammaval(gamma)
6210 The computed gamma correction value of the pixel component value,
6211 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
6213 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
6217 All expressions default to "val".
6219 @subsection Examples
6225 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
6226 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
6229 The above is the same as:
6231 lutrgb="r=negval:g=negval:b=negval"
6232 lutyuv="y=negval:u=negval:v=negval"
6242 Remove chroma components, turning the video into a graytone image:
6244 lutyuv="u=128:v=128"
6248 Apply a luma burning effect:
6254 Remove green and blue components:
6260 Set a constant alpha channel value on input:
6262 format=rgba,lutrgb=a="maxval-minval/2"
6266 Correct luminance gamma by a factor of 0.5:
6268 lutyuv=y=gammaval(0.5)
6272 Discard least significant bits of luma:
6274 lutyuv=y='bitand(val, 128+64+32)'
6278 @section mergeplanes
6280 Merge color channel components from several video streams.
6282 The filter accepts up to 4 input streams, and merge selected input
6283 planes to the output video.
6285 This filter accepts the following options:
6288 Set input to output plane mapping. Default is @code{0}.
6290 The mappings is specified as a bitmap. It should be specified as a
6291 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
6292 mapping for the first plane of the output stream. 'A' sets the number of
6293 the input stream to use (from 0 to 3), and 'a' the plane number of the
6294 corresponding input to use (from 0 to 3). The rest of the mappings is
6295 similar, 'Bb' describes the mapping for the output stream second
6296 plane, 'Cc' describes the mapping for the output stream third plane and
6297 'Dd' describes the mapping for the output stream fourth plane.
6300 Set output pixel format. Default is @code{yuva444p}.
6303 @subsection Examples
6307 Merge three gray video streams of same width and height into single video stream:
6309 [a0][a1][a2]mergeplanes=0x001020:yuv444p
6313 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
6315 [a0][a1]mergeplanes=0x00010210:yuva444p
6319 Swap Y and A plane in yuva444p stream:
6321 format=yuva444p,mergeplanes=0x03010200:yuva444p
6325 Swap U and V plane in yuv420p stream:
6327 format=yuv420p,mergeplanes=0x000201:yuv420p
6331 Cast a rgb24 clip to yuv444p:
6333 format=rgb24,mergeplanes=0x000102:yuv444p
6339 Apply motion-compensation deinterlacing.
6341 It needs one field per frame as input and must thus be used together
6342 with yadif=1/3 or equivalent.
6344 This filter accepts the following options:
6347 Set the deinterlacing mode.
6349 It accepts one of the following values:
6354 use iterative motion estimation
6356 like @samp{slow}, but use multiple reference frames.
6358 Default value is @samp{fast}.
6361 Set the picture field parity assumed for the input video. It must be
6362 one of the following values:
6366 assume top field first
6368 assume bottom field first
6371 Default value is @samp{bff}.
6374 Set per-block quantization parameter (QP) used by the internal
6377 Higher values should result in a smoother motion vector field but less
6378 optimal individual vectors. Default value is 1.
6383 Drop frames that do not differ greatly from the previous frame in
6384 order to reduce frame rate.
6386 The main use of this filter is for very-low-bitrate encoding
6387 (e.g. streaming over dialup modem), but it could in theory be used for
6388 fixing movies that were inverse-telecined incorrectly.
6390 A description of the accepted options follows.
6394 Set the maximum number of consecutive frames which can be dropped (if
6395 positive), or the minimum interval between dropped frames (if
6396 negative). If the value is 0, the frame is dropped unregarding the
6397 number of previous sequentially dropped frames.
6404 Set the dropping threshold values.
6406 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
6407 represent actual pixel value differences, so a threshold of 64
6408 corresponds to 1 unit of difference for each pixel, or the same spread
6409 out differently over the block.
6411 A frame is a candidate for dropping if no 8x8 blocks differ by more
6412 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
6413 meaning the whole image) differ by more than a threshold of @option{lo}.
6415 Default value for @option{hi} is 64*12, default value for @option{lo} is
6416 64*5, and default value for @option{frac} is 0.33.
6424 It accepts an integer in input; if non-zero it negates the
6425 alpha component (if available). The default value in input is 0.
6429 Force libavfilter not to use any of the specified pixel formats for the
6430 input to the next filter.
6432 It accepts the following parameters:
6436 A '|'-separated list of pixel format names, such as
6437 apix_fmts=yuv420p|monow|rgb24".
6441 @subsection Examples
6445 Force libavfilter to use a format different from @var{yuv420p} for the
6446 input to the vflip filter:
6448 noformat=pix_fmts=yuv420p,vflip
6452 Convert the input video to any of the formats not contained in the list:
6454 noformat=yuv420p|yuv444p|yuv410p
6460 Add noise on video input frame.
6462 The filter accepts the following options:
6470 Set noise seed for specific pixel component or all pixel components in case
6471 of @var{all_seed}. Default value is @code{123457}.
6473 @item all_strength, alls
6474 @item c0_strength, c0s
6475 @item c1_strength, c1s
6476 @item c2_strength, c2s
6477 @item c3_strength, c3s
6478 Set noise strength for specific pixel component or all pixel components in case
6479 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
6481 @item all_flags, allf
6486 Set pixel component flags or set flags for all components if @var{all_flags}.
6487 Available values for component flags are:
6490 averaged temporal noise (smoother)
6492 mix random noise with a (semi)regular pattern
6494 temporal noise (noise pattern changes between frames)
6496 uniform noise (gaussian otherwise)
6500 @subsection Examples
6502 Add temporal and uniform noise to input video:
6504 noise=alls=20:allf=t+u
6509 Pass the video source unchanged to the output.
6513 Apply a video transform using libopencv.
6515 To enable this filter, install the libopencv library and headers and
6516 configure FFmpeg with @code{--enable-libopencv}.
6518 It accepts the following parameters:
6523 The name of the libopencv filter to apply.
6526 The parameters to pass to the libopencv filter. If not specified, the default
6531 Refer to the official libopencv documentation for more precise
6533 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
6535 Several libopencv filters are supported; see the following subsections.
6540 Dilate an image by using a specific structuring element.
6541 It corresponds to the libopencv function @code{cvDilate}.
6543 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
6545 @var{struct_el} represents a structuring element, and has the syntax:
6546 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
6548 @var{cols} and @var{rows} represent the number of columns and rows of
6549 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
6550 point, and @var{shape} the shape for the structuring element. @var{shape}
6551 must be "rect", "cross", "ellipse", or "custom".
6553 If the value for @var{shape} is "custom", it must be followed by a
6554 string of the form "=@var{filename}". The file with name
6555 @var{filename} is assumed to represent a binary image, with each
6556 printable character corresponding to a bright pixel. When a custom
6557 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
6558 or columns and rows of the read file are assumed instead.
6560 The default value for @var{struct_el} is "3x3+0x0/rect".
6562 @var{nb_iterations} specifies the number of times the transform is
6563 applied to the image, and defaults to 1.
6567 # Use the default values
6570 # Dilate using a structuring element with a 5x5 cross, iterating two times
6571 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
6573 # Read the shape from the file diamond.shape, iterating two times.
6574 # The file diamond.shape may contain a pattern of characters like this
6580 # The specified columns and rows are ignored
6581 # but the anchor point coordinates are not
6582 ocv=dilate:0x0+2x2/custom=diamond.shape|2
6587 Erode an image by using a specific structuring element.
6588 It corresponds to the libopencv function @code{cvErode}.
6590 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
6591 with the same syntax and semantics as the @ref{dilate} filter.
6595 Smooth the input video.
6597 The filter takes the following parameters:
6598 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
6600 @var{type} is the type of smooth filter to apply, and must be one of
6601 the following values: "blur", "blur_no_scale", "median", "gaussian",
6602 or "bilateral". The default value is "gaussian".
6604 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
6605 depend on the smooth type. @var{param1} and
6606 @var{param2} accept integer positive values or 0. @var{param3} and
6607 @var{param4} accept floating point values.
6609 The default value for @var{param1} is 3. The default value for the
6610 other parameters is 0.
6612 These parameters correspond to the parameters assigned to the
6613 libopencv function @code{cvSmooth}.
6618 Overlay one video on top of another.
6620 It takes two inputs and has one output. The first input is the "main"
6621 video on which the second input is overlaid.
6623 It accepts the following parameters:
6625 A description of the accepted options follows.
6630 Set the expression for the x and y coordinates of the overlaid video
6631 on the main video. Default value is "0" for both expressions. In case
6632 the expression is invalid, it is set to a huge value (meaning that the
6633 overlay will not be displayed within the output visible area).
6636 The action to take when EOF is encountered on the secondary input; it accepts
6637 one of the following values:
6641 Repeat the last frame (the default).
6645 Pass the main input through.
6649 Set when the expressions for @option{x}, and @option{y} are evaluated.
6651 It accepts the following values:
6654 only evaluate expressions once during the filter initialization or
6655 when a command is processed
6658 evaluate expressions for each incoming frame
6661 Default value is @samp{frame}.
6664 If set to 1, force the output to terminate when the shortest input
6665 terminates. Default value is 0.
6668 Set the format for the output video.
6670 It accepts the following values:
6685 Default value is @samp{yuv420}.
6687 @item rgb @emph{(deprecated)}
6688 If set to 1, force the filter to accept inputs in the RGB
6689 color space. Default value is 0. This option is deprecated, use
6690 @option{format} instead.
6693 If set to 1, force the filter to draw the last overlay frame over the
6694 main input until the end of the stream. A value of 0 disables this
6695 behavior. Default value is 1.
6698 The @option{x}, and @option{y} expressions can contain the following
6704 The main input width and height.
6708 The overlay input width and height.
6712 The computed values for @var{x} and @var{y}. They are evaluated for
6717 horizontal and vertical chroma subsample values of the output
6718 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6722 the number of input frame, starting from 0
6725 the position in the file of the input frame, NAN if unknown
6728 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6732 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6733 when evaluation is done @emph{per frame}, and will evaluate to NAN
6734 when @option{eval} is set to @samp{init}.
6736 Be aware that frames are taken from each input video in timestamp
6737 order, hence, if their initial timestamps differ, it is a good idea
6738 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6739 have them begin in the same zero timestamp, as the example for
6740 the @var{movie} filter does.
6742 You can chain together more overlays but you should test the
6743 efficiency of such approach.
6745 @subsection Commands
6747 This filter supports the following commands:
6751 Modify the x and y of the overlay input.
6752 The command accepts the same syntax of the corresponding option.
6754 If the specified expression is not valid, it is kept at its current
6758 @subsection Examples
6762 Draw the overlay at 10 pixels from the bottom right corner of the main
6765 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6768 Using named options the example above becomes:
6770 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6774 Insert a transparent PNG logo in the bottom left corner of the input,
6775 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6777 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6781 Insert 2 different transparent PNG logos (second logo on bottom
6782 right corner) using the @command{ffmpeg} tool:
6784 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
6788 Add a transparent color layer on top of the main video; @code{WxH}
6789 must specify the size of the main input to the overlay filter:
6791 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6795 Play an original video and a filtered version (here with the deshake
6796 filter) side by side using the @command{ffplay} tool:
6798 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6801 The above command is the same as:
6803 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6807 Make a sliding overlay appearing from the left to the right top part of the
6808 screen starting since time 2:
6810 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6814 Compose output by putting two input videos side to side:
6816 ffmpeg -i left.avi -i right.avi -filter_complex "
6817 nullsrc=size=200x100 [background];
6818 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6819 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6820 [background][left] overlay=shortest=1 [background+left];
6821 [background+left][right] overlay=shortest=1:x=100 [left+right]
6826 Mask 10-20 seconds of a video by applying the delogo filter to a section
6828 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6829 -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]'
6834 Chain several overlays in cascade:
6836 nullsrc=s=200x200 [bg];
6837 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6838 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6839 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6840 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6841 [in3] null, [mid2] overlay=100:100 [out0]
6848 Apply Overcomplete Wavelet denoiser.
6850 The filter accepts the following options:
6856 Larger depth values will denoise lower frequency components more, but
6857 slow down filtering.
6859 Must be an int in the range 8-16, default is @code{8}.
6861 @item luma_strength, ls
6864 Must be a double value in the range 0-1000, default is @code{1.0}.
6866 @item chroma_strength, cs
6867 Set chroma strength.
6869 Must be a double value in the range 0-1000, default is @code{1.0}.
6874 Add paddings to the input image, and place the original input at the
6875 provided @var{x}, @var{y} coordinates.
6877 It accepts the following parameters:
6882 Specify an expression for the size of the output image with the
6883 paddings added. If the value for @var{width} or @var{height} is 0, the
6884 corresponding input size is used for the output.
6886 The @var{width} expression can reference the value set by the
6887 @var{height} expression, and vice versa.
6889 The default value of @var{width} and @var{height} is 0.
6893 Specify the offsets to place the input image at within the padded area,
6894 with respect to the top/left border of the output image.
6896 The @var{x} expression can reference the value set by the @var{y}
6897 expression, and vice versa.
6899 The default value of @var{x} and @var{y} is 0.
6902 Specify the color of the padded area. For the syntax of this option,
6903 check the "Color" section in the ffmpeg-utils manual.
6905 The default value of @var{color} is "black".
6908 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6909 options are expressions containing the following constants:
6914 The input video width and height.
6918 These are the same as @var{in_w} and @var{in_h}.
6922 The output width and height (the size of the padded area), as
6923 specified by the @var{width} and @var{height} expressions.
6927 These are the same as @var{out_w} and @var{out_h}.
6931 The x and y offsets as specified by the @var{x} and @var{y}
6932 expressions, or NAN if not yet specified.
6935 same as @var{iw} / @var{ih}
6938 input sample aspect ratio
6941 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6945 The horizontal and vertical chroma subsample values. For example for the
6946 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6949 @subsection Examples
6953 Add paddings with the color "violet" to the input video. The output video
6954 size is 640x480, and the top-left corner of the input video is placed at
6957 pad=640:480:0:40:violet
6960 The example above is equivalent to the following command:
6962 pad=width=640:height=480:x=0:y=40:color=violet
6966 Pad the input to get an output with dimensions increased by 3/2,
6967 and put the input video at the center of the padded area:
6969 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6973 Pad the input to get a squared output with size equal to the maximum
6974 value between the input width and height, and put the input video at
6975 the center of the padded area:
6977 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6981 Pad the input to get a final w/h ratio of 16:9:
6983 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6987 In case of anamorphic video, in order to set the output display aspect
6988 correctly, it is necessary to use @var{sar} in the expression,
6989 according to the relation:
6991 (ih * X / ih) * sar = output_dar
6992 X = output_dar / sar
6995 Thus the previous example needs to be modified to:
6997 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
7001 Double the output size and put the input video in the bottom-right
7002 corner of the output padded area:
7004 pad="2*iw:2*ih:ow-iw:oh-ih"
7011 Generate one palette for a whole video stream.
7013 It accepts the following options:
7017 Set the maximum number of colors to quantize in the palette.
7018 Note: the palette will still contain 256 colors; the unused palette entries
7021 @item reserve_transparent
7022 Create a palette of 255 colors maximum and reserve the last one for
7023 transparency. Reserving the transparency color is useful for GIF optimization.
7024 If not set, the maximum of colors in the palette will be 256. You probably want
7025 to disable this option for a standalone image.
7029 Set statistics mode.
7031 It accepts the following values:
7034 Compute full frame histograms.
7036 Compute histograms only for the part that differs from previous frame. This
7037 might be relevant to give more importance to the moving part of your input if
7038 the background is static.
7041 Default value is @var{full}.
7044 The filter also exports the frame metadata @code{lavfi.color_quant_ratio}
7045 (@code{nb_color_in / nb_color_out}) which you can use to evaluate the degree of
7046 color quantization of the palette. This information is also visible at
7047 @var{info} logging level.
7049 @subsection Examples
7053 Generate a representative palette of a given video using @command{ffmpeg}:
7055 ffmpeg -i input.mkv -vf palettegen palette.png
7061 Use a palette to downsample an input video stream.
7063 The filter takes two inputs: one video stream and a palette. The palette must
7064 be a 256 pixels image.
7066 It accepts the following options:
7070 Select dithering mode. Available algorithms are:
7073 Ordered 8x8 bayer dithering (deterministic)
7075 Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
7076 Note: this dithering is sometimes considered "wrong" and is included as a
7078 @item floyd_steinberg
7079 Floyd and Steingberg dithering (error diffusion)
7081 Frankie Sierra dithering v2 (error diffusion)
7083 Frankie Sierra dithering v2 "Lite" (error diffusion)
7086 Default is @var{sierra2_4a}.
7089 When @var{bayer} dithering is selected, this option defines the scale of the
7090 pattern (how much the crosshatch pattern is visible). A low value means more
7091 visible pattern for less banding, and higher value means less visible pattern
7092 at the cost of more banding.
7094 The option must be an integer value in the range [0,5]. Default is @var{2}.
7097 If set, define the zone to process
7101 Only the changing rectangle will be reprocessed. This is similar to GIF
7102 cropping/offsetting compression mechanism. This option can be useful for speed
7103 if only a part of the image is changing, and has use cases such as limiting the
7104 scope of the error diffusal @option{dither} to the rectangle that bounds the
7105 moving scene (it leads to more deterministic output if the scene doesn't change
7106 much, and as a result less moving noise and better GIF compression).
7109 Default is @var{none}.
7112 @subsection Examples
7116 Use a palette (generated for example with @ref{palettegen}) to encode a GIF
7117 using @command{ffmpeg}:
7119 ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
7123 @section perspective
7125 Correct perspective of video not recorded perpendicular to the screen.
7127 A description of the accepted parameters follows.
7138 Set coordinates expression for top left, top right, bottom left and bottom right corners.
7139 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
7140 If the @code{sense} option is set to @code{source}, then the specified points will be sent
7141 to the corners of the destination. If the @code{sense} option is set to @code{destination},
7142 then the corners of the source will be sent to the specified coordinates.
7144 The expressions can use the following variables:
7149 the width and height of video frame.
7153 Set interpolation for perspective correction.
7155 It accepts the following values:
7161 Default value is @samp{linear}.
7164 Set interpretation of coordinate options.
7166 It accepts the following values:
7170 Send point in the source specified by the given coordinates to
7171 the corners of the destination.
7173 @item 1, destination
7175 Send the corners of the source to the point in the destination specified
7176 by the given coordinates.
7178 Default value is @samp{source}.
7184 Delay interlaced video by one field time so that the field order changes.
7186 The intended use is to fix PAL movies that have been captured with the
7187 opposite field order to the film-to-video transfer.
7189 A description of the accepted parameters follows.
7195 It accepts the following values:
7198 Capture field order top-first, transfer bottom-first.
7199 Filter will delay the bottom field.
7202 Capture field order bottom-first, transfer top-first.
7203 Filter will delay the top field.
7206 Capture and transfer with the same field order. This mode only exists
7207 for the documentation of the other options to refer to, but if you
7208 actually select it, the filter will faithfully do nothing.
7211 Capture field order determined automatically by field flags, transfer
7213 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
7214 basis using field flags. If no field information is available,
7215 then this works just like @samp{u}.
7218 Capture unknown or varying, transfer opposite.
7219 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
7220 analyzing the images and selecting the alternative that produces best
7221 match between the fields.
7224 Capture top-first, transfer unknown or varying.
7225 Filter selects among @samp{t} and @samp{p} using image analysis.
7228 Capture bottom-first, transfer unknown or varying.
7229 Filter selects among @samp{b} and @samp{p} using image analysis.
7232 Capture determined by field flags, transfer unknown or varying.
7233 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
7234 image analysis. If no field information is available, then this works just
7235 like @samp{U}. This is the default mode.
7238 Both capture and transfer unknown or varying.
7239 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
7243 @section pixdesctest
7245 Pixel format descriptor test filter, mainly useful for internal
7246 testing. The output video should be equal to the input video.
7250 format=monow, pixdesctest
7253 can be used to test the monowhite pixel format descriptor definition.
7257 Enable the specified chain of postprocessing subfilters using libpostproc. This
7258 library should be automatically selected with a GPL build (@code{--enable-gpl}).
7259 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
7260 Each subfilter and some options have a short and a long name that can be used
7261 interchangeably, i.e. dr/dering are the same.
7263 The filters accept the following options:
7267 Set postprocessing subfilters string.
7270 All subfilters share common options to determine their scope:
7274 Honor the quality commands for this subfilter.
7277 Do chrominance filtering, too (default).
7280 Do luminance filtering only (no chrominance).
7283 Do chrominance filtering only (no luminance).
7286 These options can be appended after the subfilter name, separated by a '|'.
7288 Available subfilters are:
7291 @item hb/hdeblock[|difference[|flatness]]
7292 Horizontal deblocking filter
7295 Difference factor where higher values mean more deblocking (default: @code{32}).
7297 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7300 @item vb/vdeblock[|difference[|flatness]]
7301 Vertical deblocking filter
7304 Difference factor where higher values mean more deblocking (default: @code{32}).
7306 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7309 @item ha/hadeblock[|difference[|flatness]]
7310 Accurate horizontal deblocking filter
7313 Difference factor where higher values mean more deblocking (default: @code{32}).
7315 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7318 @item va/vadeblock[|difference[|flatness]]
7319 Accurate vertical deblocking filter
7322 Difference factor where higher values mean more deblocking (default: @code{32}).
7324 Flatness threshold where lower values mean more deblocking (default: @code{39}).
7328 The horizontal and vertical deblocking filters share the difference and
7329 flatness values so you cannot set different horizontal and vertical
7334 Experimental horizontal deblocking filter
7337 Experimental vertical deblocking filter
7342 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
7345 larger -> stronger filtering
7347 larger -> stronger filtering
7349 larger -> stronger filtering
7352 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
7355 Stretch luminance to @code{0-255}.
7358 @item lb/linblenddeint
7359 Linear blend deinterlacing filter that deinterlaces the given block by
7360 filtering all lines with a @code{(1 2 1)} filter.
7362 @item li/linipoldeint
7363 Linear interpolating deinterlacing filter that deinterlaces the given block by
7364 linearly interpolating every second line.
7366 @item ci/cubicipoldeint
7367 Cubic interpolating deinterlacing filter deinterlaces the given block by
7368 cubically interpolating every second line.
7370 @item md/mediandeint
7371 Median deinterlacing filter that deinterlaces the given block by applying a
7372 median filter to every second line.
7374 @item fd/ffmpegdeint
7375 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
7376 second line with a @code{(-1 4 2 4 -1)} filter.
7379 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
7380 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
7382 @item fq/forceQuant[|quantizer]
7383 Overrides the quantizer table from the input with the constant quantizer you
7391 Default pp filter combination (@code{hb|a,vb|a,dr|a})
7394 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
7397 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
7400 @subsection Examples
7404 Apply horizontal and vertical deblocking, deringing and automatic
7405 brightness/contrast:
7411 Apply default filters without brightness/contrast correction:
7417 Apply default filters and temporal denoiser:
7419 pp=default/tmpnoise|1|2|3
7423 Apply deblocking on luminance only, and switch vertical deblocking on or off
7424 automatically depending on available CPU time:
7431 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
7432 similar to spp = 6 with 7 point DCT, where only the center sample is
7435 The filter accepts the following options:
7439 Force a constant quantization parameter. It accepts an integer in range
7440 0 to 63. If not set, the filter will use the QP from the video stream
7444 Set thresholding mode. Available modes are:
7448 Set hard thresholding.
7450 Set soft thresholding (better de-ringing effect, but likely blurrier).
7452 Set medium thresholding (good results, default).
7458 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
7459 Ratio) between two input videos.
7461 This filter takes in input two input videos, the first input is
7462 considered the "main" source and is passed unchanged to the
7463 output. The second input is used as a "reference" video for computing
7466 Both video inputs must have the same resolution and pixel format for
7467 this filter to work correctly. Also it assumes that both inputs
7468 have the same number of frames, which are compared one by one.
7470 The obtained average PSNR is printed through the logging system.
7472 The filter stores the accumulated MSE (mean squared error) of each
7473 frame, and at the end of the processing it is averaged across all frames
7474 equally, and the following formula is applied to obtain the PSNR:
7477 PSNR = 10*log10(MAX^2/MSE)
7480 Where MAX is the average of the maximum values of each component of the
7483 The description of the accepted parameters follows.
7487 If specified the filter will use the named file to save the PSNR of
7488 each individual frame.
7491 The file printed if @var{stats_file} is selected, contains a sequence of
7492 key/value pairs of the form @var{key}:@var{value} for each compared
7495 A description of each shown parameter follows:
7499 sequential number of the input frame, starting from 1
7502 Mean Square Error pixel-by-pixel average difference of the compared
7503 frames, averaged over all the image components.
7505 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
7506 Mean Square Error pixel-by-pixel average difference of the compared
7507 frames for the component specified by the suffix.
7509 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
7510 Peak Signal to Noise ratio of the compared frames for the component
7511 specified by the suffix.
7516 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
7517 [main][ref] psnr="stats_file=stats.log" [out]
7520 On this example the input file being processed is compared with the
7521 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
7522 is stored in @file{stats.log}.
7527 Pulldown reversal (inverse telecine) filter, capable of handling mixed
7528 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
7531 The pullup filter is designed to take advantage of future context in making
7532 its decisions. This filter is stateless in the sense that it does not lock
7533 onto a pattern to follow, but it instead looks forward to the following
7534 fields in order to identify matches and rebuild progressive frames.
7536 To produce content with an even framerate, insert the fps filter after
7537 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
7538 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
7540 The filter accepts the following options:
7547 These options set the amount of "junk" to ignore at the left, right, top, and
7548 bottom of the image, respectively. Left and right are in units of 8 pixels,
7549 while top and bottom are in units of 2 lines.
7550 The default is 8 pixels on each side.
7553 Set the strict breaks. Setting this option to 1 will reduce the chances of
7554 filter generating an occasional mismatched frame, but it may also cause an
7555 excessive number of frames to be dropped during high motion sequences.
7556 Conversely, setting it to -1 will make filter match fields more easily.
7557 This may help processing of video where there is slight blurring between
7558 the fields, but may also cause there to be interlaced frames in the output.
7559 Default value is @code{0}.
7562 Set the metric plane to use. It accepts the following values:
7568 Use chroma blue plane.
7571 Use chroma red plane.
7574 This option may be set to use chroma plane instead of the default luma plane
7575 for doing filter's computations. This may improve accuracy on very clean
7576 source material, but more likely will decrease accuracy, especially if there
7577 is chroma noise (rainbow effect) or any grayscale video.
7578 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
7579 load and make pullup usable in realtime on slow machines.
7582 For best results (without duplicated frames in the output file) it is
7583 necessary to change the output frame rate. For example, to inverse
7584 telecine NTSC input:
7586 ffmpeg -i input -vf pullup -r 24000/1001 ...
7591 Change video quantization parameters (QP).
7593 The filter accepts the following option:
7597 Set expression for quantization parameter.
7600 The expression is evaluated through the eval API and can contain, among others,
7601 the following constants:
7605 1 if index is not 129, 0 otherwise.
7608 Sequentional index starting from -129 to 128.
7611 @subsection Examples
7623 Suppress a TV station logo, using an image file to determine which
7624 pixels comprise the logo. It works by filling in the pixels that
7625 comprise the logo with neighboring pixels.
7627 The filter accepts the following options:
7631 Set the filter bitmap file, which can be any image format supported by
7632 libavformat. The width and height of the image file must match those of the
7633 video stream being processed.
7636 Pixels in the provided bitmap image with a value of zero are not
7637 considered part of the logo, non-zero pixels are considered part of
7638 the logo. If you use white (255) for the logo and black (0) for the
7639 rest, you will be safe. For making the filter bitmap, it is
7640 recommended to take a screen capture of a black frame with the logo
7641 visible, and then using a threshold filter followed by the erode
7642 filter once or twice.
7644 If needed, little splotches can be fixed manually. Remember that if
7645 logo pixels are not covered, the filter quality will be much
7646 reduced. Marking too many pixels as part of the logo does not hurt as
7647 much, but it will increase the amount of blurring needed to cover over
7648 the image and will destroy more information than necessary, and extra
7649 pixels will slow things down on a large logo.
7651 @section repeatfields
7653 This filter uses the repeat_field flag from the Video ES headers and hard repeats
7654 fields based on its value.
7658 Rotate video by an arbitrary angle expressed in radians.
7660 The filter accepts the following options:
7662 A description of the optional parameters follows.
7665 Set an expression for the angle by which to rotate the input video
7666 clockwise, expressed as a number of radians. A negative value will
7667 result in a counter-clockwise rotation. By default it is set to "0".
7669 This expression is evaluated for each frame.
7672 Set the output width expression, default value is "iw".
7673 This expression is evaluated just once during configuration.
7676 Set the output height expression, default value is "ih".
7677 This expression is evaluated just once during configuration.
7680 Enable bilinear interpolation if set to 1, a value of 0 disables
7681 it. Default value is 1.
7684 Set the color used to fill the output area not covered by the rotated
7685 image. For the general syntax of this option, check the "Color" section in the
7686 ffmpeg-utils manual. If the special value "none" is selected then no
7687 background is printed (useful for example if the background is never shown).
7689 Default value is "black".
7692 The expressions for the angle and the output size can contain the
7693 following constants and functions:
7697 sequential number of the input frame, starting from 0. It is always NAN
7698 before the first frame is filtered.
7701 time in seconds of the input frame, it is set to 0 when the filter is
7702 configured. It is always NAN before the first frame is filtered.
7706 horizontal and vertical chroma subsample values. For example for the
7707 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7711 the input video width and height
7715 the output width and height, that is the size of the padded area as
7716 specified by the @var{width} and @var{height} expressions
7720 the minimal width/height required for completely containing the input
7721 video rotated by @var{a} radians.
7723 These are only available when computing the @option{out_w} and
7724 @option{out_h} expressions.
7727 @subsection Examples
7731 Rotate the input by PI/6 radians clockwise:
7737 Rotate the input by PI/6 radians counter-clockwise:
7743 Rotate the input by 45 degrees clockwise:
7749 Apply a constant rotation with period T, starting from an angle of PI/3:
7751 rotate=PI/3+2*PI*t/T
7755 Make the input video rotation oscillating with a period of T
7756 seconds and an amplitude of A radians:
7758 rotate=A*sin(2*PI/T*t)
7762 Rotate the video, output size is chosen so that the whole rotating
7763 input video is always completely contained in the output:
7765 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
7769 Rotate the video, reduce the output size so that no background is ever
7772 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
7776 @subsection Commands
7778 The filter supports the following commands:
7782 Set the angle expression.
7783 The command accepts the same syntax of the corresponding option.
7785 If the specified expression is not valid, it is kept at its current
7791 Apply Shape Adaptive Blur.
7793 The filter accepts the following options:
7796 @item luma_radius, lr
7797 Set luma blur filter strength, must be a value in range 0.1-4.0, default
7798 value is 1.0. A greater value will result in a more blurred image, and
7799 in slower processing.
7801 @item luma_pre_filter_radius, lpfr
7802 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
7805 @item luma_strength, ls
7806 Set luma maximum difference between pixels to still be considered, must
7807 be a value in the 0.1-100.0 range, default value is 1.0.
7809 @item chroma_radius, cr
7810 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
7811 greater value will result in a more blurred image, and in slower
7814 @item chroma_pre_filter_radius, cpfr
7815 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
7817 @item chroma_strength, cs
7818 Set chroma maximum difference between pixels to still be considered,
7819 must be a value in the 0.1-100.0 range.
7822 Each chroma option value, if not explicitly specified, is set to the
7823 corresponding luma option value.
7828 Scale (resize) the input video, using the libswscale library.
7830 The scale filter forces the output display aspect ratio to be the same
7831 of the input, by changing the output sample aspect ratio.
7833 If the input image format is different from the format requested by
7834 the next filter, the scale filter will convert the input to the
7838 The filter accepts the following options, or any of the options
7839 supported by the libswscale scaler.
7841 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
7842 the complete list of scaler options.
7847 Set the output video dimension expression. Default value is the input
7850 If the value is 0, the input width is used for the output.
7852 If one of the values is -1, the scale filter will use a value that
7853 maintains the aspect ratio of the input image, calculated from the
7854 other specified dimension. If both of them are -1, the input size is
7857 If one of the values is -n with n > 1, the scale filter will also use a value
7858 that maintains the aspect ratio of the input image, calculated from the other
7859 specified dimension. After that it will, however, make sure that the calculated
7860 dimension is divisible by n and adjust the value if necessary.
7862 See below for the list of accepted constants for use in the dimension
7866 Set the interlacing mode. It accepts the following values:
7870 Force interlaced aware scaling.
7873 Do not apply interlaced scaling.
7876 Select interlaced aware scaling depending on whether the source frames
7877 are flagged as interlaced or not.
7880 Default value is @samp{0}.
7883 Set libswscale scaling flags. See
7884 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7885 complete list of values. If not explicitly specified the filter applies
7889 Set the video size. For the syntax of this option, check the
7890 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
7892 @item in_color_matrix
7893 @item out_color_matrix
7894 Set in/output YCbCr color space type.
7896 This allows the autodetected value to be overridden as well as allows forcing
7897 a specific value used for the output and encoder.
7899 If not specified, the color space type depends on the pixel format.
7905 Choose automatically.
7908 Format conforming to International Telecommunication Union (ITU)
7909 Recommendation BT.709.
7912 Set color space conforming to the United States Federal Communications
7913 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7916 Set color space conforming to:
7920 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7923 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7926 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7931 Set color space conforming to SMPTE ST 240:1999.
7936 Set in/output YCbCr sample range.
7938 This allows the autodetected value to be overridden as well as allows forcing
7939 a specific value used for the output and encoder. If not specified, the
7940 range depends on the pixel format. Possible values:
7944 Choose automatically.
7947 Set full range (0-255 in case of 8-bit luma).
7950 Set "MPEG" range (16-235 in case of 8-bit luma).
7953 @item force_original_aspect_ratio
7954 Enable decreasing or increasing output video width or height if necessary to
7955 keep the original aspect ratio. Possible values:
7959 Scale the video as specified and disable this feature.
7962 The output video dimensions will automatically be decreased if needed.
7965 The output video dimensions will automatically be increased if needed.
7969 One useful instance of this option is that when you know a specific device's
7970 maximum allowed resolution, you can use this to limit the output video to
7971 that, while retaining the aspect ratio. For example, device A allows
7972 1280x720 playback, and your video is 1920x800. Using this option (set it to
7973 decrease) and specifying 1280x720 to the command line makes the output
7976 Please note that this is a different thing than specifying -1 for @option{w}
7977 or @option{h}, you still need to specify the output resolution for this option
7982 The values of the @option{w} and @option{h} options are expressions
7983 containing the following constants:
7988 The input width and height
7992 These are the same as @var{in_w} and @var{in_h}.
7996 The output (scaled) width and height
8000 These are the same as @var{out_w} and @var{out_h}
8003 The same as @var{iw} / @var{ih}
8006 input sample aspect ratio
8009 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
8013 horizontal and vertical input chroma subsample values. For example for the
8014 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
8018 horizontal and vertical output chroma subsample values. For example for the
8019 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
8022 @subsection Examples
8026 Scale the input video to a size of 200x100
8031 This is equivalent to:
8042 Specify a size abbreviation for the output size:
8047 which can also be written as:
8053 Scale the input to 2x:
8059 The above is the same as:
8065 Scale the input to 2x with forced interlaced scaling:
8067 scale=2*iw:2*ih:interl=1
8071 Scale the input to half size:
8077 Increase the width, and set the height to the same size:
8090 Increase the height, and set the width to 3/2 of the height:
8092 scale=w=3/2*oh:h=3/5*ih
8096 Increase the size, making the size a multiple of the chroma
8099 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
8103 Increase the width to a maximum of 500 pixels,
8104 keeping the same aspect ratio as the input:
8106 scale=w='min(500\, iw*3/2):h=-1'
8110 @section separatefields
8112 The @code{separatefields} takes a frame-based video input and splits
8113 each frame into its components fields, producing a new half height clip
8114 with twice the frame rate and twice the frame count.
8116 This filter use field-dominance information in frame to decide which
8117 of each pair of fields to place first in the output.
8118 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
8120 @section setdar, setsar
8122 The @code{setdar} filter sets the Display Aspect Ratio for the filter
8125 This is done by changing the specified Sample (aka Pixel) Aspect
8126 Ratio, according to the following equation:
8128 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
8131 Keep in mind that the @code{setdar} filter does not modify the pixel
8132 dimensions of the video frame. Also, the display aspect ratio set by
8133 this filter may be changed by later filters in the filterchain,
8134 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
8137 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
8138 the filter output video.
8140 Note that as a consequence of the application of this filter, the
8141 output display aspect ratio will change according to the equation
8144 Keep in mind that the sample aspect ratio set by the @code{setsar}
8145 filter may be changed by later filters in the filterchain, e.g. if
8146 another "setsar" or a "setdar" filter is applied.
8148 It accepts the following parameters:
8151 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
8152 Set the aspect ratio used by the filter.
8154 The parameter can be a floating point number string, an expression, or
8155 a string of the form @var{num}:@var{den}, where @var{num} and
8156 @var{den} are the numerator and denominator of the aspect ratio. If
8157 the parameter is not specified, it is assumed the value "0".
8158 In case the form "@var{num}:@var{den}" is used, the @code{:} character
8162 Set the maximum integer value to use for expressing numerator and
8163 denominator when reducing the expressed aspect ratio to a rational.
8164 Default value is @code{100}.
8168 The parameter @var{sar} is an expression containing
8169 the following constants:
8173 These are approximated values for the mathematical constants e
8174 (Euler's number), pi (Greek pi), and phi (the golden ratio).
8177 The input width and height.
8180 These are the same as @var{w} / @var{h}.
8183 The input sample aspect ratio.
8186 The input display aspect ratio. It is the same as
8187 (@var{w} / @var{h}) * @var{sar}.
8190 Horizontal and vertical chroma subsample values. For example, for the
8191 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
8194 @subsection Examples
8199 To change the display aspect ratio to 16:9, specify one of the following:
8207 To change the sample aspect ratio to 10:11, specify:
8213 To set a display aspect ratio of 16:9, and specify a maximum integer value of
8214 1000 in the aspect ratio reduction, use the command:
8216 setdar=ratio=16/9:max=1000
8224 Force field for the output video frame.
8226 The @code{setfield} filter marks the interlace type field for the
8227 output frames. It does not change the input frame, but only sets the
8228 corresponding property, which affects how the frame is treated by
8229 following filters (e.g. @code{fieldorder} or @code{yadif}).
8231 The filter accepts the following options:
8236 Available values are:
8240 Keep the same field property.
8243 Mark the frame as bottom-field-first.
8246 Mark the frame as top-field-first.
8249 Mark the frame as progressive.
8255 Show a line containing various information for each input video frame.
8256 The input video is not modified.
8258 The shown line contains a sequence of key/value pairs of the form
8259 @var{key}:@var{value}.
8261 The following values are shown in the output:
8265 The (sequential) number of the input frame, starting from 0.
8268 The Presentation TimeStamp of the input frame, expressed as a number of
8269 time base units. The time base unit depends on the filter input pad.
8272 The Presentation TimeStamp of the input frame, expressed as a number of
8276 The position of the frame in the input stream, or -1 if this information is
8277 unavailable and/or meaningless (for example in case of synthetic video).
8280 The pixel format name.
8283 The sample aspect ratio of the input frame, expressed in the form
8284 @var{num}/@var{den}.
8287 The size of the input frame. For the syntax of this option, check the
8288 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
8291 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
8292 for bottom field first).
8295 This is 1 if the frame is a key frame, 0 otherwise.
8298 The picture type of the input frame ("I" for an I-frame, "P" for a
8299 P-frame, "B" for a B-frame, or "?" for an unknown type).
8300 Also refer to the documentation of the @code{AVPictureType} enum and of
8301 the @code{av_get_picture_type_char} function defined in
8302 @file{libavutil/avutil.h}.
8305 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
8307 @item plane_checksum
8308 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
8309 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
8312 @section showpalette
8314 Displays the 256 colors palette of each frame. This filter is only relevant for
8315 @var{pal8} pixel format frames.
8317 It accepts the following option:
8321 Set the size of the box used to represent one palette color entry. Default is
8322 @code{30} (for a @code{30x30} pixel box).
8325 @section shuffleplanes
8327 Reorder and/or duplicate video planes.
8329 It accepts the following parameters:
8334 The index of the input plane to be used as the first output plane.
8337 The index of the input plane to be used as the second output plane.
8340 The index of the input plane to be used as the third output plane.
8343 The index of the input plane to be used as the fourth output plane.
8347 The first plane has the index 0. The default is to keep the input unchanged.
8349 Swap the second and third planes of the input:
8351 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
8354 @section signalstats
8355 Evaluate various visual metrics that assist in determining issues associated
8356 with the digitization of analog video media.
8358 By default the filter will log these metadata values:
8362 Display the minimal Y value contained within the input frame. Expressed in
8366 Display the Y value at the 10% percentile within the input frame. Expressed in
8370 Display the average Y value within the input frame. Expressed in range of
8374 Display the Y value at the 90% percentile within the input frame. Expressed in
8378 Display the maximum Y value contained within the input frame. Expressed in
8382 Display the minimal U value contained within the input frame. Expressed in
8386 Display the U value at the 10% percentile within the input frame. Expressed in
8390 Display the average U value within the input frame. Expressed in range of
8394 Display the U value at the 90% percentile within the input frame. Expressed in
8398 Display the maximum U value contained within the input frame. Expressed in
8402 Display the minimal V value contained within the input frame. Expressed in
8406 Display the V value at the 10% percentile within the input frame. Expressed in
8410 Display the average V value within the input frame. Expressed in range of
8414 Display the V value at the 90% percentile within the input frame. Expressed in
8418 Display the maximum V value contained within the input frame. Expressed in
8422 Display the minimal saturation value contained within the input frame.
8423 Expressed in range of [0-~181.02].
8426 Display the saturation value at the 10% percentile within the input frame.
8427 Expressed in range of [0-~181.02].
8430 Display the average saturation value within the input frame. Expressed in range
8434 Display the saturation value at the 90% percentile within the input frame.
8435 Expressed in range of [0-~181.02].
8438 Display the maximum saturation value contained within the input frame.
8439 Expressed in range of [0-~181.02].
8442 Display the median value for hue within the input frame. Expressed in range of
8446 Display the average value for hue within the input frame. Expressed in range of
8450 Display the average of sample value difference between all values of the Y
8451 plane in the current frame and corresponding values of the previous input frame.
8452 Expressed in range of [0-255].
8455 Display the average of sample value difference between all values of the U
8456 plane in the current frame and corresponding values of the previous input frame.
8457 Expressed in range of [0-255].
8460 Display the average of sample value difference between all values of the V
8461 plane in the current frame and corresponding values of the previous input frame.
8462 Expressed in range of [0-255].
8465 The filter accepts the following options:
8471 @option{stat} specify an additional form of image analysis.
8472 @option{out} output video with the specified type of pixel highlighted.
8474 Both options accept the following values:
8478 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
8479 unlike the neighboring pixels of the same field. Examples of temporal outliers
8480 include the results of video dropouts, head clogs, or tape tracking issues.
8483 Identify @var{vertical line repetition}. Vertical line repetition includes
8484 similar rows of pixels within a frame. In born-digital video vertical line
8485 repetition is common, but this pattern is uncommon in video digitized from an
8486 analog source. When it occurs in video that results from the digitization of an
8487 analog source it can indicate concealment from a dropout compensator.
8490 Identify pixels that fall outside of legal broadcast range.
8494 Set the highlight color for the @option{out} option. The default color is
8498 @subsection Examples
8502 Output data of various video metrics:
8504 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
8508 Output specific data about the minimum and maximum values of the Y plane per frame:
8510 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
8514 Playback video while highlighting pixels that are outside of broadcast range in red.
8516 ffplay example.mov -vf signalstats="out=brng:color=red"
8520 Playback video with signalstats metadata drawn over the frame.
8522 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
8525 The contents of signalstat_drawtext.txt used in the command are:
8528 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
8529 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
8530 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
8531 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
8539 Blur the input video without impacting the outlines.
8541 It accepts the following options:
8544 @item luma_radius, lr
8545 Set the luma radius. The option value must be a float number in
8546 the range [0.1,5.0] that specifies the variance of the gaussian filter
8547 used to blur the image (slower if larger). Default value is 1.0.
8549 @item luma_strength, ls
8550 Set the luma strength. The option value must be a float number
8551 in the range [-1.0,1.0] that configures the blurring. A value included
8552 in [0.0,1.0] will blur the image whereas a value included in
8553 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8555 @item luma_threshold, lt
8556 Set the luma threshold used as a coefficient to determine
8557 whether a pixel should be blurred or not. The option value must be an
8558 integer in the range [-30,30]. A value of 0 will filter all the image,
8559 a value included in [0,30] will filter flat areas and a value included
8560 in [-30,0] will filter edges. Default value is 0.
8562 @item chroma_radius, cr
8563 Set the chroma radius. The option value must be a float number in
8564 the range [0.1,5.0] that specifies the variance of the gaussian filter
8565 used to blur the image (slower if larger). Default value is 1.0.
8567 @item chroma_strength, cs
8568 Set the chroma strength. The option value must be a float number
8569 in the range [-1.0,1.0] that configures the blurring. A value included
8570 in [0.0,1.0] will blur the image whereas a value included in
8571 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8573 @item chroma_threshold, ct
8574 Set the chroma threshold used as a coefficient to determine
8575 whether a pixel should be blurred or not. The option value must be an
8576 integer in the range [-30,30]. A value of 0 will filter all the image,
8577 a value included in [0,30] will filter flat areas and a value included
8578 in [-30,0] will filter edges. Default value is 0.
8581 If a chroma option is not explicitly set, the corresponding luma value
8586 Convert between different stereoscopic image formats.
8588 The filters accept the following options:
8592 Set stereoscopic image format of input.
8594 Available values for input image formats are:
8597 side by side parallel (left eye left, right eye right)
8600 side by side crosseye (right eye left, left eye right)
8603 side by side parallel with half width resolution
8604 (left eye left, right eye right)
8607 side by side crosseye with half width resolution
8608 (right eye left, left eye right)
8611 above-below (left eye above, right eye below)
8614 above-below (right eye above, left eye below)
8617 above-below with half height resolution
8618 (left eye above, right eye below)
8621 above-below with half height resolution
8622 (right eye above, left eye below)
8625 alternating frames (left eye first, right eye second)
8628 alternating frames (right eye first, left eye second)
8630 Default value is @samp{sbsl}.
8634 Set stereoscopic image format of output.
8636 Available values for output image formats are all the input formats as well as:
8639 anaglyph red/blue gray
8640 (red filter on left eye, blue filter on right eye)
8643 anaglyph red/green gray
8644 (red filter on left eye, green filter on right eye)
8647 anaglyph red/cyan gray
8648 (red filter on left eye, cyan filter on right eye)
8651 anaglyph red/cyan half colored
8652 (red filter on left eye, cyan filter on right eye)
8655 anaglyph red/cyan color
8656 (red filter on left eye, cyan filter on right eye)
8659 anaglyph red/cyan color optimized with the least squares projection of dubois
8660 (red filter on left eye, cyan filter on right eye)
8663 anaglyph green/magenta gray
8664 (green filter on left eye, magenta filter on right eye)
8667 anaglyph green/magenta half colored
8668 (green filter on left eye, magenta filter on right eye)
8671 anaglyph green/magenta colored
8672 (green filter on left eye, magenta filter on right eye)
8675 anaglyph green/magenta color optimized with the least squares projection of dubois
8676 (green filter on left eye, magenta filter on right eye)
8679 anaglyph yellow/blue gray
8680 (yellow filter on left eye, blue filter on right eye)
8683 anaglyph yellow/blue half colored
8684 (yellow filter on left eye, blue filter on right eye)
8687 anaglyph yellow/blue colored
8688 (yellow filter on left eye, blue filter on right eye)
8691 anaglyph yellow/blue color optimized with the least squares projection of dubois
8692 (yellow filter on left eye, blue filter on right eye)
8695 interleaved rows (left eye has top row, right eye starts on next row)
8698 interleaved rows (right eye has top row, left eye starts on next row)
8701 mono output (left eye only)
8704 mono output (right eye only)
8707 Default value is @samp{arcd}.
8710 @subsection Examples
8714 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
8720 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
8729 Apply a simple postprocessing filter that compresses and decompresses the image
8730 at several (or - in the case of @option{quality} level @code{6} - all) shifts
8731 and average the results.
8733 The filter accepts the following options:
8737 Set quality. This option defines the number of levels for averaging. It accepts
8738 an integer in the range 0-6. If set to @code{0}, the filter will have no
8739 effect. A value of @code{6} means the higher quality. For each increment of
8740 that value the speed drops by a factor of approximately 2. Default value is
8744 Force a constant quantization parameter. If not set, the filter will use the QP
8745 from the video stream (if available).
8748 Set thresholding mode. Available modes are:
8752 Set hard thresholding (default).
8754 Set soft thresholding (better de-ringing effect, but likely blurrier).
8758 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8759 option may cause flicker since the B-Frames have often larger QP. Default is
8760 @code{0} (not enabled).
8766 Draw subtitles on top of input video using the libass library.
8768 To enable compilation of this filter you need to configure FFmpeg with
8769 @code{--enable-libass}. This filter also requires a build with libavcodec and
8770 libavformat to convert the passed subtitles file to ASS (Advanced Substation
8771 Alpha) subtitles format.
8773 The filter accepts the following options:
8777 Set the filename of the subtitle file to read. It must be specified.
8780 Specify the size of the original video, the video for which the ASS file
8781 was composed. For the syntax of this option, check the
8782 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
8783 Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
8784 correctly scale the fonts if the aspect ratio has been changed.
8787 Set subtitles input character encoding. @code{subtitles} filter only. Only
8788 useful if not UTF-8.
8790 @item stream_index, si
8791 Set subtitles stream index. @code{subtitles} filter only.
8794 Override default style or script info parameters of the subtitles. It accepts a
8795 string containing ASS style format @code{KEY=VALUE} couples separated by ",".
8798 If the first key is not specified, it is assumed that the first value
8799 specifies the @option{filename}.
8801 For example, to render the file @file{sub.srt} on top of the input
8802 video, use the command:
8807 which is equivalent to:
8809 subtitles=filename=sub.srt
8812 To render the default subtitles stream from file @file{video.mkv}, use:
8817 To render the second subtitles stream from that file, use:
8819 subtitles=video.mkv:si=1
8822 To make the subtitles stream from @file{sub.srt} appear in transparent green
8823 @code{DejaVu Serif}, use:
8825 subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'
8830 Scale the input by 2x and smooth using the Super2xSaI (Scale and
8831 Interpolate) pixel art scaling algorithm.
8833 Useful for enlarging pixel art images without reducing sharpness.
8840 Apply telecine process to the video.
8842 This filter accepts the following options:
8851 The default value is @code{top}.
8855 A string of numbers representing the pulldown pattern you wish to apply.
8856 The default value is @code{23}.
8860 Some typical patterns:
8865 24p: 2332 (preferred)
8872 24p: 222222222223 ("Euro pulldown")
8878 Select the most representative frame in a given sequence of consecutive frames.
8880 The filter accepts the following options:
8884 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
8885 will pick one of them, and then handle the next batch of @var{n} frames until
8886 the end. Default is @code{100}.
8889 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
8890 value will result in a higher memory usage, so a high value is not recommended.
8892 @subsection Examples
8896 Extract one picture each 50 frames:
8902 Complete example of a thumbnail creation with @command{ffmpeg}:
8904 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
8910 Tile several successive frames together.
8912 The filter accepts the following options:
8917 Set the grid size (i.e. the number of lines and columns). For the syntax of
8918 this option, check the
8919 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
8922 Set the maximum number of frames to render in the given area. It must be less
8923 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
8924 the area will be used.
8927 Set the outer border margin in pixels.
8930 Set the inner border thickness (i.e. the number of pixels between frames). For
8931 more advanced padding options (such as having different values for the edges),
8932 refer to the pad video filter.
8935 Specify the color of the unused area. For the syntax of this option, check the
8936 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
8940 @subsection Examples
8944 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
8946 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
8948 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
8949 duplicating each output frame to accommodate the originally detected frame
8953 Display @code{5} pictures in an area of @code{3x2} frames,
8954 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
8955 mixed flat and named options:
8957 tile=3x2:nb_frames=5:padding=7:margin=2
8963 Perform various types of temporal field interlacing.
8965 Frames are counted starting from 1, so the first input frame is
8968 The filter accepts the following options:
8973 Specify the mode of the interlacing. This option can also be specified
8974 as a value alone. See below for a list of values for this option.
8976 Available values are:
8980 Move odd frames into the upper field, even into the lower field,
8981 generating a double height frame at half frame rate.
8985 Frame 1 Frame 2 Frame 3 Frame 4
8987 11111 22222 33333 44444
8988 11111 22222 33333 44444
8989 11111 22222 33333 44444
8990 11111 22222 33333 44444
9004 Only output even frames, odd frames are dropped, generating a frame with
9005 unchanged height at half frame rate.
9010 Frame 1 Frame 2 Frame 3 Frame 4
9012 11111 22222 33333 44444
9013 11111 22222 33333 44444
9014 11111 22222 33333 44444
9015 11111 22222 33333 44444
9025 Only output odd frames, even frames are dropped, generating a frame with
9026 unchanged height at half frame rate.
9031 Frame 1 Frame 2 Frame 3 Frame 4
9033 11111 22222 33333 44444
9034 11111 22222 33333 44444
9035 11111 22222 33333 44444
9036 11111 22222 33333 44444
9046 Expand each frame to full height, but pad alternate lines with black,
9047 generating a frame with double height at the same input frame rate.
9052 Frame 1 Frame 2 Frame 3 Frame 4
9054 11111 22222 33333 44444
9055 11111 22222 33333 44444
9056 11111 22222 33333 44444
9057 11111 22222 33333 44444
9060 11111 ..... 33333 .....
9061 ..... 22222 ..... 44444
9062 11111 ..... 33333 .....
9063 ..... 22222 ..... 44444
9064 11111 ..... 33333 .....
9065 ..... 22222 ..... 44444
9066 11111 ..... 33333 .....
9067 ..... 22222 ..... 44444
9071 @item interleave_top, 4
9072 Interleave the upper field from odd frames with the lower field from
9073 even frames, generating a frame with unchanged height at half frame rate.
9078 Frame 1 Frame 2 Frame 3 Frame 4
9080 11111<- 22222 33333<- 44444
9081 11111 22222<- 33333 44444<-
9082 11111<- 22222 33333<- 44444
9083 11111 22222<- 33333 44444<-
9093 @item interleave_bottom, 5
9094 Interleave the lower field from odd frames with the upper field from
9095 even frames, generating a frame with unchanged height at half frame rate.
9100 Frame 1 Frame 2 Frame 3 Frame 4
9102 11111 22222<- 33333 44444<-
9103 11111<- 22222 33333<- 44444
9104 11111 22222<- 33333 44444<-
9105 11111<- 22222 33333<- 44444
9115 @item interlacex2, 6
9116 Double frame rate with unchanged height. Frames are inserted each
9117 containing the second temporal field from the previous input frame and
9118 the first temporal field from the next input frame. This mode relies on
9119 the top_field_first flag. Useful for interlaced video displays with no
9120 field synchronisation.
9125 Frame 1 Frame 2 Frame 3 Frame 4
9127 11111 22222 33333 44444
9128 11111 22222 33333 44444
9129 11111 22222 33333 44444
9130 11111 22222 33333 44444
9133 11111 22222 22222 33333 33333 44444 44444
9134 11111 11111 22222 22222 33333 33333 44444
9135 11111 22222 22222 33333 33333 44444 44444
9136 11111 11111 22222 22222 33333 33333 44444
9142 Numeric values are deprecated but are accepted for backward
9143 compatibility reasons.
9145 Default mode is @code{merge}.
9148 Specify flags influencing the filter process.
9150 Available value for @var{flags} is:
9153 @item low_pass_filter, vlfp
9154 Enable vertical low-pass filtering in the filter.
9155 Vertical low-pass filtering is required when creating an interlaced
9156 destination from a progressive source which contains high-frequency
9157 vertical detail. Filtering will reduce interlace 'twitter' and Moire
9160 Vertical low-pass filtering can only be enabled for @option{mode}
9161 @var{interleave_top} and @var{interleave_bottom}.
9168 Transpose rows with columns in the input video and optionally flip it.
9170 It accepts the following parameters:
9175 Specify the transposition direction.
9177 Can assume the following values:
9179 @item 0, 4, cclock_flip
9180 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
9188 Rotate by 90 degrees clockwise, that is:
9196 Rotate by 90 degrees counterclockwise, that is:
9203 @item 3, 7, clock_flip
9204 Rotate by 90 degrees clockwise and vertically flip, that is:
9212 For values between 4-7, the transposition is only done if the input
9213 video geometry is portrait and not landscape. These values are
9214 deprecated, the @code{passthrough} option should be used instead.
9216 Numerical values are deprecated, and should be dropped in favor of
9220 Do not apply the transposition if the input geometry matches the one
9221 specified by the specified value. It accepts the following values:
9224 Always apply transposition.
9226 Preserve portrait geometry (when @var{height} >= @var{width}).
9228 Preserve landscape geometry (when @var{width} >= @var{height}).
9231 Default value is @code{none}.
9234 For example to rotate by 90 degrees clockwise and preserve portrait
9237 transpose=dir=1:passthrough=portrait
9240 The command above can also be specified as:
9242 transpose=1:portrait
9246 Trim the input so that the output contains one continuous subpart of the input.
9248 It accepts the following parameters:
9251 Specify the time of the start of the kept section, i.e. the frame with the
9252 timestamp @var{start} will be the first frame in the output.
9255 Specify the time of the first frame that will be dropped, i.e. the frame
9256 immediately preceding the one with the timestamp @var{end} will be the last
9257 frame in the output.
9260 This is the same as @var{start}, except this option sets the start timestamp
9261 in timebase units instead of seconds.
9264 This is the same as @var{end}, except this option sets the end timestamp
9265 in timebase units instead of seconds.
9268 The maximum duration of the output in seconds.
9271 The number of the first frame that should be passed to the output.
9274 The number of the first frame that should be dropped.
9277 @option{start}, @option{end}, and @option{duration} are expressed as time
9278 duration specifications; see
9279 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
9280 for the accepted syntax.
9282 Note that the first two sets of the start/end options and the @option{duration}
9283 option look at the frame timestamp, while the _frame variants simply count the
9284 frames that pass through the filter. Also note that this filter does not modify
9285 the timestamps. If you wish for the output timestamps to start at zero, insert a
9286 setpts filter after the trim filter.
9288 If multiple start or end options are set, this filter tries to be greedy and
9289 keep all the frames that match at least one of the specified constraints. To keep
9290 only the part that matches all the constraints at once, chain multiple trim
9293 The defaults are such that all the input is kept. So it is possible to set e.g.
9294 just the end values to keep everything before the specified time.
9299 Drop everything except the second minute of input:
9301 ffmpeg -i INPUT -vf trim=60:120
9305 Keep only the first second:
9307 ffmpeg -i INPUT -vf trim=duration=1
9316 Sharpen or blur the input video.
9318 It accepts the following parameters:
9321 @item luma_msize_x, lx
9322 Set the luma matrix horizontal size. It must be an odd integer between
9323 3 and 63. The default value is 5.
9325 @item luma_msize_y, ly
9326 Set the luma matrix vertical size. It must be an odd integer between 3
9327 and 63. The default value is 5.
9329 @item luma_amount, la
9330 Set the luma effect strength. It must be a floating point number, reasonable
9331 values lay between -1.5 and 1.5.
9333 Negative values will blur the input video, while positive values will
9334 sharpen it, a value of zero will disable the effect.
9336 Default value is 1.0.
9338 @item chroma_msize_x, cx
9339 Set the chroma matrix horizontal size. It must be an odd integer
9340 between 3 and 63. The default value is 5.
9342 @item chroma_msize_y, cy
9343 Set the chroma matrix vertical size. It must be an odd integer
9344 between 3 and 63. The default value is 5.
9346 @item chroma_amount, ca
9347 Set the chroma effect strength. It must be a floating point number, reasonable
9348 values lay between -1.5 and 1.5.
9350 Negative values will blur the input video, while positive values will
9351 sharpen it, a value of zero will disable the effect.
9353 Default value is 0.0.
9356 If set to 1, specify using OpenCL capabilities, only available if
9357 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
9361 All parameters are optional and default to the equivalent of the
9362 string '5:5:1.0:5:5:0.0'.
9364 @subsection Examples
9368 Apply strong luma sharpen effect:
9370 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
9374 Apply a strong blur of both luma and chroma parameters:
9376 unsharp=7:7:-2:7:7:-2
9382 Apply ultra slow/simple postprocessing filter that compresses and decompresses
9383 the image at several (or - in the case of @option{quality} level @code{8} - all)
9384 shifts and average the results.
9386 The way this differs from the behavior of spp is that uspp actually encodes &
9387 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
9388 DCT similar to MJPEG.
9390 The filter accepts the following options:
9394 Set quality. This option defines the number of levels for averaging. It accepts
9395 an integer in the range 0-8. If set to @code{0}, the filter will have no
9396 effect. A value of @code{8} means the higher quality. For each increment of
9397 that value the speed drops by a factor of approximately 2. Default value is
9401 Force a constant quantization parameter. If not set, the filter will use the QP
9402 from the video stream (if available).
9405 @anchor{vidstabdetect}
9406 @section vidstabdetect
9408 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
9409 @ref{vidstabtransform} for pass 2.
9411 This filter generates a file with relative translation and rotation
9412 transform information about subsequent frames, which is then used by
9413 the @ref{vidstabtransform} filter.
9415 To enable compilation of this filter you need to configure FFmpeg with
9416 @code{--enable-libvidstab}.
9418 This filter accepts the following options:
9422 Set the path to the file used to write the transforms information.
9423 Default value is @file{transforms.trf}.
9426 Set how shaky the video is and how quick the camera is. It accepts an
9427 integer in the range 1-10, a value of 1 means little shakiness, a
9428 value of 10 means strong shakiness. Default value is 5.
9431 Set the accuracy of the detection process. It must be a value in the
9432 range 1-15. A value of 1 means low accuracy, a value of 15 means high
9433 accuracy. Default value is 15.
9436 Set stepsize of the search process. The region around minimum is
9437 scanned with 1 pixel resolution. Default value is 6.
9440 Set minimum contrast. Below this value a local measurement field is
9441 discarded. Must be a floating point value in the range 0-1. Default
9445 Set reference frame number for tripod mode.
9447 If enabled, the motion of the frames is compared to a reference frame
9448 in the filtered stream, identified by the specified number. The idea
9449 is to compensate all movements in a more-or-less static scene and keep
9450 the camera view absolutely still.
9452 If set to 0, it is disabled. The frames are counted starting from 1.
9455 Show fields and transforms in the resulting frames. It accepts an
9456 integer in the range 0-2. Default value is 0, which disables any
9460 @subsection Examples
9470 Analyze strongly shaky movie and put the results in file
9471 @file{mytransforms.trf}:
9473 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
9477 Visualize the result of internal transformations in the resulting
9480 vidstabdetect=show=1
9484 Analyze a video with medium shakiness using @command{ffmpeg}:
9486 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
9490 @anchor{vidstabtransform}
9491 @section vidstabtransform
9493 Video stabilization/deshaking: pass 2 of 2,
9494 see @ref{vidstabdetect} for pass 1.
9496 Read a file with transform information for each frame and
9497 apply/compensate them. Together with the @ref{vidstabdetect}
9498 filter this can be used to deshake videos. See also
9499 @url{http://public.hronopik.de/vid.stab}. It is important to also use
9500 the @ref{unsharp} filter, see below.
9502 To enable compilation of this filter you need to configure FFmpeg with
9503 @code{--enable-libvidstab}.
9509 Set path to the file used to read the transforms. Default value is
9510 @file{transforms.trf}.
9513 Set the number of frames (value*2 + 1) used for lowpass filtering the
9514 camera movements. Default value is 10.
9516 For example a number of 10 means that 21 frames are used (10 in the
9517 past and 10 in the future) to smoothen the motion in the video. A
9518 larger value leads to a smoother video, but limits the acceleration of
9519 the camera (pan/tilt movements). 0 is a special case where a static
9520 camera is simulated.
9523 Set the camera path optimization algorithm.
9525 Accepted values are:
9528 gaussian kernel low-pass filter on camera motion (default)
9530 averaging on transformations
9534 Set maximal number of pixels to translate frames. Default value is -1,
9538 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
9539 value is -1, meaning no limit.
9542 Specify how to deal with borders that may be visible due to movement
9545 Available values are:
9548 keep image information from previous frame (default)
9550 fill the border black
9554 Invert transforms if set to 1. Default value is 0.
9557 Consider transforms as relative to previous frame if set to 1,
9558 absolute if set to 0. Default value is 0.
9561 Set percentage to zoom. A positive value will result in a zoom-in
9562 effect, a negative value in a zoom-out effect. Default value is 0 (no
9566 Set optimal zooming to avoid borders.
9568 Accepted values are:
9573 optimal static zoom value is determined (only very strong movements
9574 will lead to visible borders) (default)
9576 optimal adaptive zoom value is determined (no borders will be
9577 visible), see @option{zoomspeed}
9580 Note that the value given at zoom is added to the one calculated here.
9583 Set percent to zoom maximally each frame (enabled when
9584 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
9588 Specify type of interpolation.
9590 Available values are:
9595 linear only horizontal
9597 linear in both directions (default)
9599 cubic in both directions (slow)
9603 Enable virtual tripod mode if set to 1, which is equivalent to
9604 @code{relative=0:smoothing=0}. Default value is 0.
9606 Use also @code{tripod} option of @ref{vidstabdetect}.
9609 Increase log verbosity if set to 1. Also the detected global motions
9610 are written to the temporary file @file{global_motions.trf}. Default
9614 @subsection Examples
9618 Use @command{ffmpeg} for a typical stabilization with default values:
9620 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
9623 Note the use of the @ref{unsharp} filter which is always recommended.
9626 Zoom in a bit more and load transform data from a given file:
9628 vidstabtransform=zoom=5:input="mytransforms.trf"
9632 Smoothen the video even more:
9634 vidstabtransform=smoothing=30
9640 Flip the input video vertically.
9642 For example, to vertically flip a video with @command{ffmpeg}:
9644 ffmpeg -i in.avi -vf "vflip" out.avi
9650 Make or reverse a natural vignetting effect.
9652 The filter accepts the following options:
9656 Set lens angle expression as a number of radians.
9658 The value is clipped in the @code{[0,PI/2]} range.
9660 Default value: @code{"PI/5"}
9664 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
9668 Set forward/backward mode.
9670 Available modes are:
9673 The larger the distance from the central point, the darker the image becomes.
9676 The larger the distance from the central point, the brighter the image becomes.
9677 This can be used to reverse a vignette effect, though there is no automatic
9678 detection to extract the lens @option{angle} and other settings (yet). It can
9679 also be used to create a burning effect.
9682 Default value is @samp{forward}.
9685 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
9687 It accepts the following values:
9690 Evaluate expressions only once during the filter initialization.
9693 Evaluate expressions for each incoming frame. This is way slower than the
9694 @samp{init} mode since it requires all the scalers to be re-computed, but it
9695 allows advanced dynamic expressions.
9698 Default value is @samp{init}.
9701 Set dithering to reduce the circular banding effects. Default is @code{1}
9705 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
9706 Setting this value to the SAR of the input will make a rectangular vignetting
9707 following the dimensions of the video.
9709 Default is @code{1/1}.
9712 @subsection Expressions
9714 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
9715 following parameters.
9720 input width and height
9723 the number of input frame, starting from 0
9726 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
9727 @var{TB} units, NAN if undefined
9730 frame rate of the input video, NAN if the input frame rate is unknown
9733 the PTS (Presentation TimeStamp) of the filtered video frame,
9734 expressed in seconds, NAN if undefined
9737 time base of the input video
9741 @subsection Examples
9745 Apply simple strong vignetting effect:
9751 Make a flickering vignetting:
9753 vignette='PI/4+random(1)*PI/50':eval=frame
9760 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
9761 Deinterlacing Filter").
9763 Based on the process described by Martin Weston for BBC R&D, and
9764 implemented based on the de-interlace algorithm written by Jim
9765 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
9766 uses filter coefficients calculated by BBC R&D.
9768 There are two sets of filter coefficients, so called "simple":
9769 and "complex". Which set of filter coefficients is used can
9770 be set by passing an optional parameter:
9774 Set the interlacing filter coefficients. Accepts one of the following values:
9778 Simple filter coefficient set.
9780 More-complex filter coefficient set.
9782 Default value is @samp{complex}.
9785 Specify which frames to deinterlace. Accept one of the following values:
9789 Deinterlace all frames,
9791 Only deinterlace frames marked as interlaced.
9794 Default value is @samp{all}.
9798 Apply the xBR high-quality magnification filter which is designed for pixel
9799 art. It follows a set of edge-detection rules, see
9800 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
9802 It accepts the following option:
9806 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
9807 @code{3xBR} and @code{4} for @code{4xBR}.
9808 Default is @code{3}.
9814 Deinterlace the input video ("yadif" means "yet another deinterlacing
9817 It accepts the following parameters:
9823 The interlacing mode to adopt. It accepts one of the following values:
9827 Output one frame for each frame.
9829 Output one frame for each field.
9830 @item 2, send_frame_nospatial
9831 Like @code{send_frame}, but it skips the spatial interlacing check.
9832 @item 3, send_field_nospatial
9833 Like @code{send_field}, but it skips the spatial interlacing check.
9836 The default value is @code{send_frame}.
9839 The picture field parity assumed for the input interlaced video. It accepts one
9840 of the following values:
9844 Assume the top field is first.
9846 Assume the bottom field is first.
9848 Enable automatic detection of field parity.
9851 The default value is @code{auto}.
9852 If the interlacing is unknown or the decoder does not export this information,
9853 top field first will be assumed.
9856 Specify which frames to deinterlace. Accept one of the following
9861 Deinterlace all frames.
9863 Only deinterlace frames marked as interlaced.
9866 The default value is @code{all}.
9871 Apply Zoom & Pan effect.
9873 This filter accepts the following options:
9877 Set the zoom expression. Default is 1.
9881 Set the x and y expression. Default is 0.
9884 Set the duration expression in number of frames.
9885 This sets for how many number of frames effect will last for
9889 Set the output image size, default is 'hd720'.
9892 Each expression can contain the following constants:
9915 Last calculated 'x' and 'y' position from 'x' and 'y' expression
9916 for current input frame.
9920 'x' and 'y' of last output frame of previous input frame or 0 when there was
9921 not yet such frame (first input frame).
9924 Last calculated zoom from 'z' expression for current input frame.
9927 Last calculated zoom of last output frame of previous input frame.
9930 Number of output frames for current input frame. Calculated from 'd' expression
9931 for each input frame.
9934 number of output frames created for previous input frame
9937 Rational number: input width / input height
9943 display aspect ratio
9947 @subsection Examples
9951 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
9953 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
9957 @c man end VIDEO FILTERS
9959 @chapter Video Sources
9960 @c man begin VIDEO SOURCES
9962 Below is a description of the currently available video sources.
9966 Buffer video frames, and make them available to the filter chain.
9968 This source is mainly intended for a programmatic use, in particular
9969 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
9971 It accepts the following parameters:
9976 Specify the size (width and height) of the buffered video frames. For the
9977 syntax of this option, check the
9978 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
9981 The input video width.
9984 The input video height.
9987 A string representing the pixel format of the buffered video frames.
9988 It may be a number corresponding to a pixel format, or a pixel format
9992 Specify the timebase assumed by the timestamps of the buffered frames.
9995 Specify the frame rate expected for the video stream.
9997 @item pixel_aspect, sar
9998 The sample (pixel) aspect ratio of the input video.
10001 Specify the optional parameters to be used for the scale filter which
10002 is automatically inserted when an input change is detected in the
10003 input size or format.
10008 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
10011 will instruct the source to accept video frames with size 320x240 and
10012 with format "yuv410p", assuming 1/24 as the timestamps timebase and
10013 square pixels (1:1 sample aspect ratio).
10014 Since the pixel format with name "yuv410p" corresponds to the number 6
10015 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
10016 this example corresponds to:
10018 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
10021 Alternatively, the options can be specified as a flat string, but this
10022 syntax is deprecated:
10024 @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}]
10028 Create a pattern generated by an elementary cellular automaton.
10030 The initial state of the cellular automaton can be defined through the
10031 @option{filename}, and @option{pattern} options. If such options are
10032 not specified an initial state is created randomly.
10034 At each new frame a new row in the video is filled with the result of
10035 the cellular automaton next generation. The behavior when the whole
10036 frame is filled is defined by the @option{scroll} option.
10038 This source accepts the following options:
10042 Read the initial cellular automaton state, i.e. the starting row, from
10043 the specified file.
10044 In the file, each non-whitespace character is considered an alive
10045 cell, a newline will terminate the row, and further characters in the
10046 file will be ignored.
10049 Read the initial cellular automaton state, i.e. the starting row, from
10050 the specified string.
10052 Each non-whitespace character in the string is considered an alive
10053 cell, a newline will terminate the row, and further characters in the
10054 string will be ignored.
10057 Set the video rate, that is the number of frames generated per second.
10060 @item random_fill_ratio, ratio
10061 Set the random fill ratio for the initial cellular automaton row. It
10062 is a floating point number value ranging from 0 to 1, defaults to
10065 This option is ignored when a file or a pattern is specified.
10067 @item random_seed, seed
10068 Set the seed for filling randomly the initial row, must be an integer
10069 included between 0 and UINT32_MAX. If not specified, or if explicitly
10070 set to -1, the filter will try to use a good random seed on a best
10074 Set the cellular automaton rule, it is a number ranging from 0 to 255.
10075 Default value is 110.
10078 Set the size of the output video. For the syntax of this option, check the
10079 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10081 If @option{filename} or @option{pattern} is specified, the size is set
10082 by default to the width of the specified initial state row, and the
10083 height is set to @var{width} * PHI.
10085 If @option{size} is set, it must contain the width of the specified
10086 pattern string, and the specified pattern will be centered in the
10089 If a filename or a pattern string is not specified, the size value
10090 defaults to "320x518" (used for a randomly generated initial state).
10093 If set to 1, scroll the output upward when all the rows in the output
10094 have been already filled. If set to 0, the new generated row will be
10095 written over the top row just after the bottom row is filled.
10098 @item start_full, full
10099 If set to 1, completely fill the output with generated rows before
10100 outputting the first frame.
10101 This is the default behavior, for disabling set the value to 0.
10104 If set to 1, stitch the left and right row edges together.
10105 This is the default behavior, for disabling set the value to 0.
10108 @subsection Examples
10112 Read the initial state from @file{pattern}, and specify an output of
10115 cellauto=f=pattern:s=200x400
10119 Generate a random initial row with a width of 200 cells, with a fill
10122 cellauto=ratio=2/3:s=200x200
10126 Create a pattern generated by rule 18 starting by a single alive cell
10127 centered on an initial row with width 100:
10129 cellauto=p=@@:s=100x400:full=0:rule=18
10133 Specify a more elaborated initial pattern:
10135 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
10140 @section mandelbrot
10142 Generate a Mandelbrot set fractal, and progressively zoom towards the
10143 point specified with @var{start_x} and @var{start_y}.
10145 This source accepts the following options:
10150 Set the terminal pts value. Default value is 400.
10153 Set the terminal scale value.
10154 Must be a floating point value. Default value is 0.3.
10157 Set the inner coloring mode, that is the algorithm used to draw the
10158 Mandelbrot fractal internal region.
10160 It shall assume one of the following values:
10165 Show time until convergence.
10167 Set color based on point closest to the origin of the iterations.
10172 Default value is @var{mincol}.
10175 Set the bailout value. Default value is 10.0.
10178 Set the maximum of iterations performed by the rendering
10179 algorithm. Default value is 7189.
10182 Set outer coloring mode.
10183 It shall assume one of following values:
10185 @item iteration_count
10186 Set iteration cound mode.
10187 @item normalized_iteration_count
10188 set normalized iteration count mode.
10190 Default value is @var{normalized_iteration_count}.
10193 Set frame rate, expressed as number of frames per second. Default
10197 Set frame size. For the syntax of this option, check the "Video
10198 size" section in the ffmpeg-utils manual. Default value is "640x480".
10201 Set the initial scale value. Default value is 3.0.
10204 Set the initial x position. Must be a floating point value between
10205 -100 and 100. Default value is -0.743643887037158704752191506114774.
10208 Set the initial y position. Must be a floating point value between
10209 -100 and 100. Default value is -0.131825904205311970493132056385139.
10214 Generate various test patterns, as generated by the MPlayer test filter.
10216 The size of the generated video is fixed, and is 256x256.
10217 This source is useful in particular for testing encoding features.
10219 This source accepts the following options:
10224 Specify the frame rate of the sourced video, as the number of frames
10225 generated per second. It has to be a string in the format
10226 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
10227 number or a valid video frame rate abbreviation. The default value is
10231 Set the duration of the sourced video. See
10232 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
10233 for the accepted syntax.
10235 If not specified, or the expressed duration is negative, the video is
10236 supposed to be generated forever.
10240 Set the number or the name of the test to perform. Supported tests are:
10256 Default value is "all", which will cycle through the list of all tests.
10261 mptestsrc=t=dc_luma
10264 will generate a "dc_luma" test pattern.
10266 @section frei0r_src
10268 Provide a frei0r source.
10270 To enable compilation of this filter you need to install the frei0r
10271 header and configure FFmpeg with @code{--enable-frei0r}.
10273 This source accepts the following parameters:
10278 The size of the video to generate. For the syntax of this option, check the
10279 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10282 The framerate of the generated video. It may be a string of the form
10283 @var{num}/@var{den} or a frame rate abbreviation.
10286 The name to the frei0r source to load. For more information regarding frei0r and
10287 how to set the parameters, read the @ref{frei0r} section in the video filters
10290 @item filter_params
10291 A '|'-separated list of parameters to pass to the frei0r source.
10295 For example, to generate a frei0r partik0l source with size 200x200
10296 and frame rate 10 which is overlaid on the overlay filter main input:
10298 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
10303 Generate a life pattern.
10305 This source is based on a generalization of John Conway's life game.
10307 The sourced input represents a life grid, each pixel represents a cell
10308 which can be in one of two possible states, alive or dead. Every cell
10309 interacts with its eight neighbours, which are the cells that are
10310 horizontally, vertically, or diagonally adjacent.
10312 At each interaction the grid evolves according to the adopted rule,
10313 which specifies the number of neighbor alive cells which will make a
10314 cell stay alive or born. The @option{rule} option allows one to specify
10317 This source accepts the following options:
10321 Set the file from which to read the initial grid state. In the file,
10322 each non-whitespace character is considered an alive cell, and newline
10323 is used to delimit the end of each row.
10325 If this option is not specified, the initial grid is generated
10329 Set the video rate, that is the number of frames generated per second.
10332 @item random_fill_ratio, ratio
10333 Set the random fill ratio for the initial random grid. It is a
10334 floating point number value ranging from 0 to 1, defaults to 1/PHI.
10335 It is ignored when a file is specified.
10337 @item random_seed, seed
10338 Set the seed for filling the initial random grid, must be an integer
10339 included between 0 and UINT32_MAX. If not specified, or if explicitly
10340 set to -1, the filter will try to use a good random seed on a best
10346 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
10347 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
10348 @var{NS} specifies the number of alive neighbor cells which make a
10349 live cell stay alive, and @var{NB} the number of alive neighbor cells
10350 which make a dead cell to become alive (i.e. to "born").
10351 "s" and "b" can be used in place of "S" and "B", respectively.
10353 Alternatively a rule can be specified by an 18-bits integer. The 9
10354 high order bits are used to encode the next cell state if it is alive
10355 for each number of neighbor alive cells, the low order bits specify
10356 the rule for "borning" new cells. Higher order bits encode for an
10357 higher number of neighbor cells.
10358 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
10359 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
10361 Default value is "S23/B3", which is the original Conway's game of life
10362 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
10363 cells, and will born a new cell if there are three alive cells around
10367 Set the size of the output video. For the syntax of this option, check the
10368 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10370 If @option{filename} is specified, the size is set by default to the
10371 same size of the input file. If @option{size} is set, it must contain
10372 the size specified in the input file, and the initial grid defined in
10373 that file is centered in the larger resulting area.
10375 If a filename is not specified, the size value defaults to "320x240"
10376 (used for a randomly generated initial grid).
10379 If set to 1, stitch the left and right grid edges together, and the
10380 top and bottom edges also. Defaults to 1.
10383 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
10384 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
10385 value from 0 to 255.
10388 Set the color of living (or new born) cells.
10391 Set the color of dead cells. If @option{mold} is set, this is the first color
10392 used to represent a dead cell.
10395 Set mold color, for definitely dead and moldy cells.
10397 For the syntax of these 3 color options, check the "Color" section in the
10398 ffmpeg-utils manual.
10401 @subsection Examples
10405 Read a grid from @file{pattern}, and center it on a grid of size
10408 life=f=pattern:s=300x300
10412 Generate a random grid of size 200x200, with a fill ratio of 2/3:
10414 life=ratio=2/3:s=200x200
10418 Specify a custom rule for evolving a randomly generated grid:
10424 Full example with slow death effect (mold) using @command{ffplay}:
10426 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
10431 @anchor{haldclutsrc}
10433 @anchor{rgbtestsrc}
10435 @anchor{smptehdbars}
10437 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
10439 The @code{color} source provides an uniformly colored input.
10441 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
10442 @ref{haldclut} filter.
10444 The @code{nullsrc} source returns unprocessed video frames. It is
10445 mainly useful to be employed in analysis / debugging tools, or as the
10446 source for filters which ignore the input data.
10448 The @code{rgbtestsrc} source generates an RGB test pattern useful for
10449 detecting RGB vs BGR issues. You should see a red, green and blue
10450 stripe from top to bottom.
10452 The @code{smptebars} source generates a color bars pattern, based on
10453 the SMPTE Engineering Guideline EG 1-1990.
10455 The @code{smptehdbars} source generates a color bars pattern, based on
10456 the SMPTE RP 219-2002.
10458 The @code{testsrc} source generates a test video pattern, showing a
10459 color pattern, a scrolling gradient and a timestamp. This is mainly
10460 intended for testing purposes.
10462 The sources accept the following parameters:
10467 Specify the color of the source, only available in the @code{color}
10468 source. For the syntax of this option, check the "Color" section in the
10469 ffmpeg-utils manual.
10472 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
10473 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
10474 pixels to be used as identity matrix for 3D lookup tables. Each component is
10475 coded on a @code{1/(N*N)} scale.
10478 Specify the size of the sourced video. For the syntax of this option, check the
10479 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10480 The default value is @code{320x240}.
10482 This option is not available with the @code{haldclutsrc} filter.
10485 Specify the frame rate of the sourced video, as the number of frames
10486 generated per second. It has to be a string in the format
10487 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
10488 number or a valid video frame rate abbreviation. The default value is
10492 Set the sample aspect ratio of the sourced video.
10495 Set the duration of the sourced video. See
10496 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
10497 for the accepted syntax.
10499 If not specified, or the expressed duration is negative, the video is
10500 supposed to be generated forever.
10503 Set the number of decimals to show in the timestamp, only available in the
10504 @code{testsrc} source.
10506 The displayed timestamp value will correspond to the original
10507 timestamp value multiplied by the power of 10 of the specified
10508 value. Default value is 0.
10511 For example the following:
10513 testsrc=duration=5.3:size=qcif:rate=10
10516 will generate a video with a duration of 5.3 seconds, with size
10517 176x144 and a frame rate of 10 frames per second.
10519 The following graph description will generate a red source
10520 with an opacity of 0.2, with size "qcif" and a frame rate of 10
10523 color=c=red@@0.2:s=qcif:r=10
10526 If the input content is to be ignored, @code{nullsrc} can be used. The
10527 following command generates noise in the luminance plane by employing
10528 the @code{geq} filter:
10530 nullsrc=s=256x256, geq=random(1)*255:128:128
10533 @subsection Commands
10535 The @code{color} source supports the following commands:
10539 Set the color of the created image. Accepts the same syntax of the
10540 corresponding @option{color} option.
10543 @c man end VIDEO SOURCES
10545 @chapter Video Sinks
10546 @c man begin VIDEO SINKS
10548 Below is a description of the currently available video sinks.
10550 @section buffersink
10552 Buffer video frames, and make them available to the end of the filter
10555 This sink is mainly intended for programmatic use, in particular
10556 through the interface defined in @file{libavfilter/buffersink.h}
10557 or the options system.
10559 It accepts a pointer to an AVBufferSinkContext structure, which
10560 defines the incoming buffers' formats, to be passed as the opaque
10561 parameter to @code{avfilter_init_filter} for initialization.
10565 Null video sink: do absolutely nothing with the input video. It is
10566 mainly useful as a template and for use in analysis / debugging
10569 @c man end VIDEO SINKS
10571 @chapter Multimedia Filters
10572 @c man begin MULTIMEDIA FILTERS
10574 Below is a description of the currently available multimedia filters.
10576 @section avectorscope
10578 Convert input audio to a video output, representing the audio vector
10581 The filter is used to measure the difference between channels of stereo
10582 audio stream. A monoaural signal, consisting of identical left and right
10583 signal, results in straight vertical line. Any stereo separation is visible
10584 as a deviation from this line, creating a Lissajous figure.
10585 If the straight (or deviation from it) but horizontal line appears this
10586 indicates that the left and right channels are out of phase.
10588 The filter accepts the following options:
10592 Set the vectorscope mode.
10594 Available values are:
10597 Lissajous rotated by 45 degrees.
10600 Same as above but not rotated.
10603 Default value is @samp{lissajous}.
10606 Set the video size for the output. For the syntax of this option, check the
10607 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10608 Default value is @code{400x400}.
10611 Set the output frame rate. Default value is @code{25}.
10616 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
10617 Allowed range is @code{[0, 255]}.
10622 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
10623 Allowed range is @code{[0, 255]}.
10626 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
10629 @subsection Examples
10633 Complete example using @command{ffplay}:
10635 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10636 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
10642 Concatenate audio and video streams, joining them together one after the
10645 The filter works on segments of synchronized video and audio streams. All
10646 segments must have the same number of streams of each type, and that will
10647 also be the number of streams at output.
10649 The filter accepts the following options:
10654 Set the number of segments. Default is 2.
10657 Set the number of output video streams, that is also the number of video
10658 streams in each segment. Default is 1.
10661 Set the number of output audio streams, that is also the number of audio
10662 streams in each segment. Default is 0.
10665 Activate unsafe mode: do not fail if segments have a different format.
10669 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
10670 @var{a} audio outputs.
10672 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
10673 segment, in the same order as the outputs, then the inputs for the second
10676 Related streams do not always have exactly the same duration, for various
10677 reasons including codec frame size or sloppy authoring. For that reason,
10678 related synchronized streams (e.g. a video and its audio track) should be
10679 concatenated at once. The concat filter will use the duration of the longest
10680 stream in each segment (except the last one), and if necessary pad shorter
10681 audio streams with silence.
10683 For this filter to work correctly, all segments must start at timestamp 0.
10685 All corresponding streams must have the same parameters in all segments; the
10686 filtering system will automatically select a common pixel format for video
10687 streams, and a common sample format, sample rate and channel layout for
10688 audio streams, but other settings, such as resolution, must be converted
10689 explicitly by the user.
10691 Different frame rates are acceptable but will result in variable frame rate
10692 at output; be sure to configure the output file to handle it.
10694 @subsection Examples
10698 Concatenate an opening, an episode and an ending, all in bilingual version
10699 (video in stream 0, audio in streams 1 and 2):
10701 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
10702 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
10703 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
10704 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
10708 Concatenate two parts, handling audio and video separately, using the
10709 (a)movie sources, and adjusting the resolution:
10711 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
10712 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
10713 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
10715 Note that a desync will happen at the stitch if the audio and video streams
10716 do not have exactly the same duration in the first file.
10722 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
10723 it unchanged. By default, it logs a message at a frequency of 10Hz with the
10724 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
10725 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
10727 The filter also has a video output (see the @var{video} option) with a real
10728 time graph to observe the loudness evolution. The graphic contains the logged
10729 message mentioned above, so it is not printed anymore when this option is set,
10730 unless the verbose logging is set. The main graphing area contains the
10731 short-term loudness (3 seconds of analysis), and the gauge on the right is for
10732 the momentary loudness (400 milliseconds).
10734 More information about the Loudness Recommendation EBU R128 on
10735 @url{http://tech.ebu.ch/loudness}.
10737 The filter accepts the following options:
10742 Activate the video output. The audio stream is passed unchanged whether this
10743 option is set or no. The video stream will be the first output stream if
10744 activated. Default is @code{0}.
10747 Set the video size. This option is for video only. For the syntax of this
10749 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10750 Default and minimum resolution is @code{640x480}.
10753 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
10754 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
10755 other integer value between this range is allowed.
10758 Set metadata injection. If set to @code{1}, the audio input will be segmented
10759 into 100ms output frames, each of them containing various loudness information
10760 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
10762 Default is @code{0}.
10765 Force the frame logging level.
10767 Available values are:
10770 information logging level
10772 verbose logging level
10775 By default, the logging level is set to @var{info}. If the @option{video} or
10776 the @option{metadata} options are set, it switches to @var{verbose}.
10781 Available modes can be cumulated (the option is a @code{flag} type). Possible
10785 Disable any peak mode (default).
10787 Enable sample-peak mode.
10789 Simple peak mode looking for the higher sample value. It logs a message
10790 for sample-peak (identified by @code{SPK}).
10792 Enable true-peak mode.
10794 If enabled, the peak lookup is done on an over-sampled version of the input
10795 stream for better peak accuracy. It logs a message for true-peak.
10796 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
10797 This mode requires a build with @code{libswresample}.
10802 @subsection Examples
10806 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
10808 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
10812 Run an analysis with @command{ffmpeg}:
10814 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
10818 @section interleave, ainterleave
10820 Temporally interleave frames from several inputs.
10822 @code{interleave} works with video inputs, @code{ainterleave} with audio.
10824 These filters read frames from several inputs and send the oldest
10825 queued frame to the output.
10827 Input streams must have a well defined, monotonically increasing frame
10830 In order to submit one frame to output, these filters need to enqueue
10831 at least one frame for each input, so they cannot work in case one
10832 input is not yet terminated and will not receive incoming frames.
10834 For example consider the case when one input is a @code{select} filter
10835 which always drop input frames. The @code{interleave} filter will keep
10836 reading from that input, but it will never be able to send new frames
10837 to output until the input will send an end-of-stream signal.
10839 Also, depending on inputs synchronization, the filters will drop
10840 frames in case one input receives more frames than the other ones, and
10841 the queue is already filled.
10843 These filters accept the following options:
10847 Set the number of different inputs, it is 2 by default.
10850 @subsection Examples
10854 Interleave frames belonging to different streams using @command{ffmpeg}:
10856 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
10860 Add flickering blur effect:
10862 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
10866 @section perms, aperms
10868 Set read/write permissions for the output frames.
10870 These filters are mainly aimed at developers to test direct path in the
10871 following filter in the filtergraph.
10873 The filters accept the following options:
10877 Select the permissions mode.
10879 It accepts the following values:
10882 Do nothing. This is the default.
10884 Set all the output frames read-only.
10886 Set all the output frames directly writable.
10888 Make the frame read-only if writable, and writable if read-only.
10890 Set each output frame read-only or writable randomly.
10894 Set the seed for the @var{random} mode, must be an integer included between
10895 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
10896 @code{-1}, the filter will try to use a good random seed on a best effort
10900 Note: in case of auto-inserted filter between the permission filter and the
10901 following one, the permission might not be received as expected in that
10902 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
10903 perms/aperms filter can avoid this problem.
10905 @section select, aselect
10907 Select frames to pass in output.
10909 This filter accepts the following options:
10914 Set expression, which is evaluated for each input frame.
10916 If the expression is evaluated to zero, the frame is discarded.
10918 If the evaluation result is negative or NaN, the frame is sent to the
10919 first output; otherwise it is sent to the output with index
10920 @code{ceil(val)-1}, assuming that the input index starts from 0.
10922 For example a value of @code{1.2} corresponds to the output with index
10923 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
10926 Set the number of outputs. The output to which to send the selected
10927 frame is based on the result of the evaluation. Default value is 1.
10930 The expression can contain the following constants:
10934 The (sequential) number of the filtered frame, starting from 0.
10937 The (sequential) number of the selected frame, starting from 0.
10939 @item prev_selected_n
10940 The sequential number of the last selected frame. It's NAN if undefined.
10943 The timebase of the input timestamps.
10946 The PTS (Presentation TimeStamp) of the filtered video frame,
10947 expressed in @var{TB} units. It's NAN if undefined.
10950 The PTS of the filtered video frame,
10951 expressed in seconds. It's NAN if undefined.
10954 The PTS of the previously filtered video frame. It's NAN if undefined.
10956 @item prev_selected_pts
10957 The PTS of the last previously filtered video frame. It's NAN if undefined.
10959 @item prev_selected_t
10960 The PTS of the last previously selected video frame. It's NAN if undefined.
10963 The PTS of the first video frame in the video. It's NAN if undefined.
10966 The time of the first video frame in the video. It's NAN if undefined.
10968 @item pict_type @emph{(video only)}
10969 The type of the filtered frame. It can assume one of the following
10981 @item interlace_type @emph{(video only)}
10982 The frame interlace type. It can assume one of the following values:
10985 The frame is progressive (not interlaced).
10987 The frame is top-field-first.
10989 The frame is bottom-field-first.
10992 @item consumed_sample_n @emph{(audio only)}
10993 the number of selected samples before the current frame
10995 @item samples_n @emph{(audio only)}
10996 the number of samples in the current frame
10998 @item sample_rate @emph{(audio only)}
10999 the input sample rate
11002 This is 1 if the filtered frame is a key-frame, 0 otherwise.
11005 the position in the file of the filtered frame, -1 if the information
11006 is not available (e.g. for synthetic video)
11008 @item scene @emph{(video only)}
11009 value between 0 and 1 to indicate a new scene; a low value reflects a low
11010 probability for the current frame to introduce a new scene, while a higher
11011 value means the current frame is more likely to be one (see the example below)
11015 The default value of the select expression is "1".
11017 @subsection Examples
11021 Select all frames in input:
11026 The example above is the same as:
11038 Select only I-frames:
11040 select='eq(pict_type\,I)'
11044 Select one frame every 100:
11046 select='not(mod(n\,100))'
11050 Select only frames contained in the 10-20 time interval:
11052 select=between(t\,10\,20)
11056 Select only I frames contained in the 10-20 time interval:
11058 select=between(t\,10\,20)*eq(pict_type\,I)
11062 Select frames with a minimum distance of 10 seconds:
11064 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
11068 Use aselect to select only audio frames with samples number > 100:
11070 aselect='gt(samples_n\,100)'
11074 Create a mosaic of the first scenes:
11076 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
11079 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
11083 Send even and odd frames to separate outputs, and compose them:
11085 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
11089 @section sendcmd, asendcmd
11091 Send commands to filters in the filtergraph.
11093 These filters read commands to be sent to other filters in the
11096 @code{sendcmd} must be inserted between two video filters,
11097 @code{asendcmd} must be inserted between two audio filters, but apart
11098 from that they act the same way.
11100 The specification of commands can be provided in the filter arguments
11101 with the @var{commands} option, or in a file specified by the
11102 @var{filename} option.
11104 These filters accept the following options:
11107 Set the commands to be read and sent to the other filters.
11109 Set the filename of the commands to be read and sent to the other
11113 @subsection Commands syntax
11115 A commands description consists of a sequence of interval
11116 specifications, comprising a list of commands to be executed when a
11117 particular event related to that interval occurs. The occurring event
11118 is typically the current frame time entering or leaving a given time
11121 An interval is specified by the following syntax:
11123 @var{START}[-@var{END}] @var{COMMANDS};
11126 The time interval is specified by the @var{START} and @var{END} times.
11127 @var{END} is optional and defaults to the maximum time.
11129 The current frame time is considered within the specified interval if
11130 it is included in the interval [@var{START}, @var{END}), that is when
11131 the time is greater or equal to @var{START} and is lesser than
11134 @var{COMMANDS} consists of a sequence of one or more command
11135 specifications, separated by ",", relating to that interval. The
11136 syntax of a command specification is given by:
11138 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
11141 @var{FLAGS} is optional and specifies the type of events relating to
11142 the time interval which enable sending the specified command, and must
11143 be a non-null sequence of identifier flags separated by "+" or "|" and
11144 enclosed between "[" and "]".
11146 The following flags are recognized:
11149 The command is sent when the current frame timestamp enters the
11150 specified interval. In other words, the command is sent when the
11151 previous frame timestamp was not in the given interval, and the
11155 The command is sent when the current frame timestamp leaves the
11156 specified interval. In other words, the command is sent when the
11157 previous frame timestamp was in the given interval, and the
11161 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
11164 @var{TARGET} specifies the target of the command, usually the name of
11165 the filter class or a specific filter instance name.
11167 @var{COMMAND} specifies the name of the command for the target filter.
11169 @var{ARG} is optional and specifies the optional list of argument for
11170 the given @var{COMMAND}.
11172 Between one interval specification and another, whitespaces, or
11173 sequences of characters starting with @code{#} until the end of line,
11174 are ignored and can be used to annotate comments.
11176 A simplified BNF description of the commands specification syntax
11179 @var{COMMAND_FLAG} ::= "enter" | "leave"
11180 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
11181 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
11182 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
11183 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
11184 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
11187 @subsection Examples
11191 Specify audio tempo change at second 4:
11193 asendcmd=c='4.0 atempo tempo 1.5',atempo
11197 Specify a list of drawtext and hue commands in a file.
11199 # show text in the interval 5-10
11200 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
11201 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
11203 # desaturate the image in the interval 15-20
11204 15.0-20.0 [enter] hue s 0,
11205 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
11207 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
11209 # apply an exponential saturation fade-out effect, starting from time 25
11210 25 [enter] hue s exp(25-t)
11213 A filtergraph allowing to read and process the above command list
11214 stored in a file @file{test.cmd}, can be specified with:
11216 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
11221 @section setpts, asetpts
11223 Change the PTS (presentation timestamp) of the input frames.
11225 @code{setpts} works on video frames, @code{asetpts} on audio frames.
11227 This filter accepts the following options:
11232 The expression which is evaluated for each frame to construct its timestamp.
11236 The expression is evaluated through the eval API and can contain the following
11241 frame rate, only defined for constant frame-rate video
11244 The presentation timestamp in input
11247 The count of the input frame for video or the number of consumed samples,
11248 not including the current frame for audio, starting from 0.
11250 @item NB_CONSUMED_SAMPLES
11251 The number of consumed samples, not including the current frame (only
11254 @item NB_SAMPLES, S
11255 The number of samples in the current frame (only audio)
11257 @item SAMPLE_RATE, SR
11258 The audio sample rate.
11261 The PTS of the first frame.
11264 the time in seconds of the first frame
11267 State whether the current frame is interlaced.
11270 the time in seconds of the current frame
11273 original position in the file of the frame, or undefined if undefined
11274 for the current frame
11277 The previous input PTS.
11280 previous input time in seconds
11283 The previous output PTS.
11286 previous output time in seconds
11289 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
11293 The wallclock (RTC) time at the start of the movie in microseconds.
11296 The timebase of the input timestamps.
11300 @subsection Examples
11304 Start counting PTS from zero
11306 setpts=PTS-STARTPTS
11310 Apply fast motion effect:
11316 Apply slow motion effect:
11322 Set fixed rate of 25 frames per second:
11328 Set fixed rate 25 fps with some jitter:
11330 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
11334 Apply an offset of 10 seconds to the input PTS:
11340 Generate timestamps from a "live source" and rebase onto the current timebase:
11342 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
11346 Generate timestamps by counting samples:
11353 @section settb, asettb
11355 Set the timebase to use for the output frames timestamps.
11356 It is mainly useful for testing timebase configuration.
11358 It accepts the following parameters:
11363 The expression which is evaluated into the output timebase.
11367 The value for @option{tb} is an arithmetic expression representing a
11368 rational. The expression can contain the constants "AVTB" (the default
11369 timebase), "intb" (the input timebase) and "sr" (the sample rate,
11370 audio only). Default value is "intb".
11372 @subsection Examples
11376 Set the timebase to 1/25:
11382 Set the timebase to 1/10:
11388 Set the timebase to 1001/1000:
11394 Set the timebase to 2*intb:
11400 Set the default timebase value:
11407 Convert input audio to a video output representing
11408 frequency spectrum logarithmically (using constant Q transform with
11409 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
11411 The filter accepts the following options:
11415 Specify transform volume (multiplier) expression. The expression can contain
11418 @item frequency, freq, f
11419 the frequency where transform is evaluated
11420 @item timeclamp, tc
11421 value of timeclamp option
11425 @item a_weighting(f)
11426 A-weighting of equal loudness
11427 @item b_weighting(f)
11428 B-weighting of equal loudness
11429 @item c_weighting(f)
11430 C-weighting of equal loudness
11432 Default value is @code{16}.
11435 Specify transform length expression. The expression can contain variables:
11437 @item frequency, freq, f
11438 the frequency where transform is evaluated
11439 @item timeclamp, tc
11440 value of timeclamp option
11442 Default value is @code{384/f*tc/(384/f+tc)}.
11445 Specify the transform timeclamp. At low frequency, there is trade-off between
11446 accuracy in time domain and frequency domain. If timeclamp is lower,
11447 event in time domain is represented more accurately (such as fast bass drum),
11448 otherwise event in frequency domain is represented more accurately
11449 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
11452 Specify the transform coeffclamp. If coeffclamp is lower, transform is
11453 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
11454 Default value is @code{1.0}.
11457 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
11458 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
11459 Default value is @code{3.0}.
11462 Specify gamma of bargraph. Acceptable value is [1.0, 7.0].
11463 Default value is @code{1.0}.
11466 Specify font file for use with freetype. If not specified, use embedded font.
11469 Specify font color expression. This is arithmetic expression that should return
11470 integer value 0xRRGGBB. The expression can contain variables:
11472 @item frequency, freq, f
11473 the frequency where transform is evaluated
11474 @item timeclamp, tc
11475 value of timeclamp option
11480 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
11481 @item r(x), g(x), b(x)
11482 red, green, and blue value of intensity x
11484 Default value is @code{st(0, (midi(f)-59.5)/12);
11485 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
11486 r(1-ld(1)) + b(ld(1))}
11489 If set to 1 (the default), the video size is 1920x1080 (full HD),
11490 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
11493 Specify video fps. Default value is @code{25}.
11496 Specify number of transform per frame, so there are fps*count transforms
11497 per second. Note that audio data rate must be divisible by fps*count.
11498 Default value is @code{6}.
11502 @subsection Examples
11506 Playing audio while showing the spectrum:
11508 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
11512 Same as above, but with frame rate 30 fps:
11514 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
11518 Playing at 960x540 and lower CPU usage:
11520 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
11524 A1 and its harmonics: A1, A2, (near)E3, A3:
11526 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),
11527 asplit[a][out1]; [a] showcqt [out0]'
11531 Same as above, but with more accuracy in frequency domain (and slower):
11533 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),
11534 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
11538 B-weighting of equal loudness
11540 volume=16*b_weighting(f)
11546 tlength=100/f*tc/(100/f+tc)
11550 Custom fontcolor, C-note is colored green, others are colored blue
11552 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))'
11556 Custom gamma, now spectrum is linear to the amplitude.
11563 @section showspectrum
11565 Convert input audio to a video output, representing the audio frequency
11568 The filter accepts the following options:
11572 Specify the video size for the output. For the syntax of this option, check the
11573 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11574 Default value is @code{640x512}.
11577 Specify how the spectrum should slide along the window.
11579 It accepts the following values:
11582 the samples start again on the left when they reach the right
11584 the samples scroll from right to left
11586 frames are only produced when the samples reach the right
11589 Default value is @code{replace}.
11592 Specify display mode.
11594 It accepts the following values:
11597 all channels are displayed in the same row
11599 all channels are displayed in separate rows
11602 Default value is @samp{combined}.
11605 Specify display color mode.
11607 It accepts the following values:
11610 each channel is displayed in a separate color
11612 each channel is is displayed using the same color scheme
11615 Default value is @samp{channel}.
11618 Specify scale used for calculating intensity color values.
11620 It accepts the following values:
11625 square root, default
11632 Default value is @samp{sqrt}.
11635 Set saturation modifier for displayed colors. Negative values provide
11636 alternative color scheme. @code{0} is no saturation at all.
11637 Saturation must be in [-10.0, 10.0] range.
11638 Default value is @code{1}.
11641 Set window function.
11643 It accepts the following values:
11646 No samples pre-processing (do not expect this to be faster)
11655 Default value is @code{hann}.
11658 The usage is very similar to the showwaves filter; see the examples in that
11661 @subsection Examples
11665 Large window with logarithmic color scaling:
11667 showspectrum=s=1280x480:scale=log
11671 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
11673 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
11674 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
11680 Convert input audio to a video output, representing the samples waves.
11682 The filter accepts the following options:
11686 Specify the video size for the output. For the syntax of this option, check the
11687 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11688 Default value is @code{600x240}.
11693 Available values are:
11696 Draw a point for each sample.
11699 Draw a vertical line for each sample.
11702 Draw a point for each sample and a line between them.
11705 Draw a centered vertical line for each sample.
11708 Default value is @code{point}.
11711 Set the number of samples which are printed on the same column. A
11712 larger value will decrease the frame rate. Must be a positive
11713 integer. This option can be set only if the value for @var{rate}
11714 is not explicitly specified.
11717 Set the (approximate) output frame rate. This is done by setting the
11718 option @var{n}. Default value is "25".
11720 @item split_channels
11721 Set if channels should be drawn separately or overlap. Default value is 0.
11725 @subsection Examples
11729 Output the input file audio and the corresponding video representation
11732 amovie=a.mp3,asplit[out0],showwaves[out1]
11736 Create a synthetic signal and show it with showwaves, forcing a
11737 frame rate of 30 frames per second:
11739 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
11743 @section split, asplit
11745 Split input into several identical outputs.
11747 @code{asplit} works with audio input, @code{split} with video.
11749 The filter accepts a single parameter which specifies the number of outputs. If
11750 unspecified, it defaults to 2.
11752 @subsection Examples
11756 Create two separate outputs from the same input:
11758 [in] split [out0][out1]
11762 To create 3 or more outputs, you need to specify the number of
11765 [in] asplit=3 [out0][out1][out2]
11769 Create two separate outputs from the same input, one cropped and
11772 [in] split [splitout1][splitout2];
11773 [splitout1] crop=100:100:0:0 [cropout];
11774 [splitout2] pad=200:200:100:100 [padout];
11778 Create 5 copies of the input audio with @command{ffmpeg}:
11780 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
11786 Receive commands sent through a libzmq client, and forward them to
11787 filters in the filtergraph.
11789 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
11790 must be inserted between two video filters, @code{azmq} between two
11793 To enable these filters you need to install the libzmq library and
11794 headers and configure FFmpeg with @code{--enable-libzmq}.
11796 For more information about libzmq see:
11797 @url{http://www.zeromq.org/}
11799 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
11800 receives messages sent through a network interface defined by the
11801 @option{bind_address} option.
11803 The received message must be in the form:
11805 @var{TARGET} @var{COMMAND} [@var{ARG}]
11808 @var{TARGET} specifies the target of the command, usually the name of
11809 the filter class or a specific filter instance name.
11811 @var{COMMAND} specifies the name of the command for the target filter.
11813 @var{ARG} is optional and specifies the optional argument list for the
11814 given @var{COMMAND}.
11816 Upon reception, the message is processed and the corresponding command
11817 is injected into the filtergraph. Depending on the result, the filter
11818 will send a reply to the client, adopting the format:
11820 @var{ERROR_CODE} @var{ERROR_REASON}
11824 @var{MESSAGE} is optional.
11826 @subsection Examples
11828 Look at @file{tools/zmqsend} for an example of a zmq client which can
11829 be used to send commands processed by these filters.
11831 Consider the following filtergraph generated by @command{ffplay}
11833 ffplay -dumpgraph 1 -f lavfi "
11834 color=s=100x100:c=red [l];
11835 color=s=100x100:c=blue [r];
11836 nullsrc=s=200x100, zmq [bg];
11837 [bg][l] overlay [bg+l];
11838 [bg+l][r] overlay=x=100 "
11841 To change the color of the left side of the video, the following
11842 command can be used:
11844 echo Parsed_color_0 c yellow | tools/zmqsend
11847 To change the right side:
11849 echo Parsed_color_1 c pink | tools/zmqsend
11852 @c man end MULTIMEDIA FILTERS
11854 @chapter Multimedia Sources
11855 @c man begin MULTIMEDIA SOURCES
11857 Below is a description of the currently available multimedia sources.
11861 This is the same as @ref{movie} source, except it selects an audio
11867 Read audio and/or video stream(s) from a movie container.
11869 It accepts the following parameters:
11873 The name of the resource to read (not necessarily a file; it can also be a
11874 device or a stream accessed through some protocol).
11876 @item format_name, f
11877 Specifies the format assumed for the movie to read, and can be either
11878 the name of a container or an input device. If not specified, the
11879 format is guessed from @var{movie_name} or by probing.
11881 @item seek_point, sp
11882 Specifies the seek point in seconds. The frames will be output
11883 starting from this seek point. The parameter is evaluated with
11884 @code{av_strtod}, so the numerical value may be suffixed by an IS
11885 postfix. The default value is "0".
11888 Specifies the streams to read. Several streams can be specified,
11889 separated by "+". The source will then have as many outputs, in the
11890 same order. The syntax is explained in the ``Stream specifiers''
11891 section in the ffmpeg manual. Two special names, "dv" and "da" specify
11892 respectively the default (best suited) video and audio stream. Default
11893 is "dv", or "da" if the filter is called as "amovie".
11895 @item stream_index, si
11896 Specifies the index of the video stream to read. If the value is -1,
11897 the most suitable video stream will be automatically selected. The default
11898 value is "-1". Deprecated. If the filter is called "amovie", it will select
11899 audio instead of video.
11902 Specifies how many times to read the stream in sequence.
11903 If the value is less than 1, the stream will be read again and again.
11904 Default value is "1".
11906 Note that when the movie is looped the source timestamps are not
11907 changed, so it will generate non monotonically increasing timestamps.
11910 It allows overlaying a second video on top of the main input of
11911 a filtergraph, as shown in this graph:
11913 input -----------> deltapts0 --> overlay --> output
11916 movie --> scale--> deltapts1 -------+
11918 @subsection Examples
11922 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
11923 on top of the input labelled "in":
11925 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
11926 [in] setpts=PTS-STARTPTS [main];
11927 [main][over] overlay=16:16 [out]
11931 Read from a video4linux2 device, and overlay it on top of the input
11934 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
11935 [in] setpts=PTS-STARTPTS [main];
11936 [main][over] overlay=16:16 [out]
11940 Read the first video stream and the audio stream with id 0x81 from
11941 dvd.vob; the video is connected to the pad named "video" and the audio is
11942 connected to the pad named "audio":
11944 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
11948 @c man end MULTIMEDIA SOURCES