1 @chapter Filtering Introduction
2 @c man begin FILTERING INTRODUCTION
4 Filtering in FFmpeg is enabled through the libavfilter library.
6 In libavfilter, a filter can have multiple inputs and multiple
8 To illustrate the sorts of things that are possible, we consider the
13 input --> split ---------------------> overlay --> output
16 +-----> crop --> vflip -------+
19 This filtergraph splits the input stream in two streams, then sends one
20 stream through the crop filter and the vflip filter, before merging it
21 back with the other stream by overlaying it on top. You can use the
22 following command to achieve this:
25 ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
28 The result will be that the top half of the video is mirrored
29 onto the bottom half of the output video.
31 Filters in the same linear chain are separated by commas, and distinct
32 linear chains of filters are separated by semicolons. In our example,
33 @var{crop,vflip} are in one linear chain, @var{split} and
34 @var{overlay} are separately in another. The points where the linear
35 chains join are labelled by names enclosed in square brackets. In the
36 example, the split filter generates two outputs that are associated to
37 the labels @var{[main]} and @var{[tmp]}.
39 The stream sent to the second output of @var{split}, labelled as
40 @var{[tmp]}, is processed through the @var{crop} filter, which crops
41 away the lower half part of the video, and then vertically flipped. The
42 @var{overlay} filter takes in input the first unchanged output of the
43 split filter (which was labelled as @var{[main]}), and overlay on its
44 lower half the output generated by the @var{crop,vflip} filterchain.
46 Some filters take in input a list of parameters: they are specified
47 after the filter name and an equal sign, and are separated from each other
50 There exist so-called @var{source filters} that do not have an
51 audio/video input, and @var{sink filters} that will not have audio/video
54 @c man end FILTERING INTRODUCTION
57 @c man begin GRAPH2DOT
59 The @file{graph2dot} program included in the FFmpeg @file{tools}
60 directory can be used to parse a filtergraph description and issue a
61 corresponding textual representation in the dot language.
68 to see how to use @file{graph2dot}.
70 You can then pass the dot description to the @file{dot} program (from
71 the graphviz suite of programs) and obtain a graphical representation
74 For example the sequence of commands:
76 echo @var{GRAPH_DESCRIPTION} | \
77 tools/graph2dot -o graph.tmp && \
78 dot -Tpng graph.tmp -o graph.png && \
82 can be used to create and display an image representing the graph
83 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
84 a complete self-contained graph, with its inputs and outputs explicitly defined.
85 For example if your command line is of the form:
87 ffmpeg -i infile -vf scale=640:360 outfile
89 your @var{GRAPH_DESCRIPTION} string will need to be of the form:
91 nullsrc,scale=640:360,nullsink
93 you may also need to set the @var{nullsrc} parameters and add a @var{format}
94 filter in order to simulate a specific input file.
98 @chapter Filtergraph description
99 @c man begin FILTERGRAPH DESCRIPTION
101 A filtergraph is a directed graph of connected filters. It can contain
102 cycles, and there can be multiple links between a pair of
103 filters. Each link has one input pad on one side connecting it to one
104 filter from which it takes its input, and one output pad on the other
105 side connecting it to one filter accepting its output.
107 Each filter in a filtergraph is an instance of a filter class
108 registered in the application, which defines the features and the
109 number of input and output pads of the filter.
111 A filter with no input pads is called a "source", and a filter with no
112 output pads is called a "sink".
114 @anchor{Filtergraph syntax}
115 @section Filtergraph syntax
117 A filtergraph has a textual representation, which is recognized by the
118 @option{-filter}/@option{-vf}/@option{-af} and
119 @option{-filter_complex} options in @command{ffmpeg} and
120 @option{-vf}/@option{-af} in @command{ffplay}, and by the
121 @code{avfilter_graph_parse_ptr()} function defined in
122 @file{libavfilter/avfilter.h}.
124 A filterchain consists of a sequence of connected filters, each one
125 connected to the previous one in the sequence. A filterchain is
126 represented by a list of ","-separated filter descriptions.
128 A filtergraph consists of a sequence of filterchains. A sequence of
129 filterchains is represented by a list of ";"-separated filterchain
132 A filter is represented by a string of the form:
133 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
135 @var{filter_name} is the name of the filter class of which the
136 described filter is an instance of, and has to be the name of one of
137 the filter classes registered in the program.
138 The name of the filter class is optionally followed by a string
141 @var{arguments} is a string which contains the parameters used to
142 initialize the filter instance. It may have one of two forms:
146 A ':'-separated list of @var{key=value} pairs.
149 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
150 the option names in the order they are declared. E.g. the @code{fade} filter
151 declares three options in this order -- @option{type}, @option{start_frame} and
152 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
153 @var{in} is assigned to the option @option{type}, @var{0} to
154 @option{start_frame} and @var{30} to @option{nb_frames}.
157 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
158 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
159 follow the same constraints order of the previous point. The following
160 @var{key=value} pairs can be set in any preferred order.
164 If the option value itself is a list of items (e.g. the @code{format} filter
165 takes a list of pixel formats), the items in the list are usually separated by
168 The list of arguments can be quoted using the character @samp{'} as initial
169 and ending mark, and the character @samp{\} for escaping the characters
170 within the quoted text; otherwise the argument string is considered
171 terminated when the next special character (belonging to the set
172 @samp{[]=;,}) is encountered.
174 The name and arguments of the filter are optionally preceded and
175 followed by a list of link labels.
176 A link label allows one to name a link and associate it to a filter output
177 or input pad. The preceding labels @var{in_link_1}
178 ... @var{in_link_N}, are associated to the filter input pads,
179 the following labels @var{out_link_1} ... @var{out_link_M}, are
180 associated to the output pads.
182 When two link labels with the same name are found in the
183 filtergraph, a link between the corresponding input and output pad is
186 If an output pad is not labelled, it is linked by default to the first
187 unlabelled input pad of the next filter in the filterchain.
188 For example in the filterchain
190 nullsrc, split[L1], [L2]overlay, nullsink
192 the split filter instance has two output pads, and the overlay filter
193 instance two input pads. The first output pad of split is labelled
194 "L1", the first input pad of overlay is labelled "L2", and the second
195 output pad of split is linked to the second input pad of overlay,
196 which are both unlabelled.
198 In a filter description, if the input label of the first filter is not
199 specified, "in" is assumed; if the output label of the last filter is not
200 specified, "out" is assumed.
202 In a complete filterchain all the unlabelled filter input and output
203 pads must be connected. A filtergraph is considered valid if all the
204 filter input and output pads of all the filterchains are connected.
206 Libavfilter will automatically insert @ref{scale} filters where format
207 conversion is required. It is possible to specify swscale flags
208 for those automatically inserted scalers by prepending
209 @code{sws_flags=@var{flags};}
210 to the filtergraph description.
212 Here is a BNF description of the filtergraph syntax:
214 @var{NAME} ::= sequence of alphanumeric characters and '_'
215 @var{LINKLABEL} ::= "[" @var{NAME} "]"
216 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
217 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
218 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
219 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
220 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
223 @section Notes on filtergraph escaping
225 Filtergraph description composition entails several levels of
226 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
227 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
228 information about the employed escaping procedure.
230 A first level escaping affects the content of each filter option
231 value, which may contain the special character @code{:} used to
232 separate values, or one of the escaping characters @code{\'}.
234 A second level escaping affects the whole filter description, which
235 may contain the escaping characters @code{\'} or the special
236 characters @code{[],;} used by the filtergraph description.
238 Finally, when you specify a filtergraph on a shell commandline, you
239 need to perform a third level escaping for the shell special
240 characters contained within it.
242 For example, consider the following string to be embedded in
243 the @ref{drawtext} filter description @option{text} value:
245 this is a 'string': may contain one, or more, special characters
248 This string contains the @code{'} special escaping character, and the
249 @code{:} special character, so it needs to be escaped in this way:
251 text=this is a \'string\'\: may contain one, or more, special characters
254 A second level of escaping is required when embedding the filter
255 description in a filtergraph description, in order to escape all the
256 filtergraph special characters. Thus the example above becomes:
258 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
260 (note that in addition to the @code{\'} escaping special characters,
261 also @code{,} needs to be escaped).
263 Finally an additional level of escaping is needed when writing the
264 filtergraph description in a shell command, which depends on the
265 escaping rules of the adopted shell. For example, assuming that
266 @code{\} is special and needs to be escaped with another @code{\}, the
267 previous string will finally result in:
269 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
272 @chapter Timeline editing
274 Some filters support a generic @option{enable} option. For the filters
275 supporting timeline editing, this option can be set to an expression which is
276 evaluated before sending a frame to the filter. If the evaluation is non-zero,
277 the filter will be enabled, otherwise the frame will be sent unchanged to the
278 next filter in the filtergraph.
280 The expression accepts the following values:
283 timestamp expressed in seconds, NAN if the input timestamp is unknown
286 sequential number of the input frame, starting from 0
289 the position in the file of the input frame, NAN if unknown
293 width and height of the input frame if video
296 Additionally, these filters support an @option{enable} command that can be used
297 to re-define the expression.
299 Like any other filtering option, the @option{enable} option follows the same
302 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
303 minutes, and a @ref{curves} filter starting at 3 seconds:
305 smartblur = enable='between(t,10,3*60)',
306 curves = enable='gte(t,3)' : preset=cross_process
309 @c man end FILTERGRAPH DESCRIPTION
311 @chapter Audio Filters
312 @c man begin AUDIO FILTERS
314 When you configure your FFmpeg build, you can disable any of the
315 existing filters using @code{--disable-filters}.
316 The configure output will show the audio filters included in your
319 Below is a description of the currently available audio filters.
323 Apply cross fade from one input audio stream to another input audio stream.
324 The cross fade is applied for specified duration near the end of first stream.
326 The filter accepts the following options:
330 Specify the number of samples for which the cross fade effect has to last.
331 At the end of the cross fade effect the first input audio will be completely
332 silent. Default is 44100.
335 Specify the duration of the cross fade effect. See
336 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
337 for the accepted syntax.
338 By default the duration is determined by @var{nb_samples}.
339 If set this option is used instead of @var{nb_samples}.
342 Should first stream end overlap with second stream start. Default is enabled.
345 Set curve for cross fade transition for first stream.
348 Set curve for cross fade transition for second stream.
350 For description of available curve types see @ref{afade} filter description.
357 Cross fade from one input to another:
359 ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:c1=exp:c2=exp output.flac
363 Cross fade from one input to another but without overlapping:
365 ffmpeg -i first.flac -i second.flac -filter_complex acrossfade=d=10:o=0:c1=exp:c2=exp output.flac
371 Delay one or more audio channels.
373 Samples in delayed channel are filled with silence.
375 The filter accepts the following option:
379 Set list of delays in milliseconds for each channel separated by '|'.
380 At least one delay greater than 0 should be provided.
381 Unused delays will be silently ignored. If number of given delays is
382 smaller than number of channels all remaining channels will not be delayed.
389 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
390 the second channel (and any other channels that may be present) unchanged.
398 Apply echoing to the input audio.
400 Echoes are reflected sound and can occur naturally amongst mountains
401 (and sometimes large buildings) when talking or shouting; digital echo
402 effects emulate this behaviour and are often used to help fill out the
403 sound of a single instrument or vocal. The time difference between the
404 original signal and the reflection is the @code{delay}, and the
405 loudness of the reflected signal is the @code{decay}.
406 Multiple echoes can have different delays and decays.
408 A description of the accepted parameters follows.
412 Set input gain of reflected signal. Default is @code{0.6}.
415 Set output gain of reflected signal. Default is @code{0.3}.
418 Set list of time intervals in milliseconds between original signal and reflections
419 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
420 Default is @code{1000}.
423 Set list of loudnesses of reflected signals separated by '|'.
424 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
425 Default is @code{0.5}.
432 Make it sound as if there are twice as many instruments as are actually playing:
434 aecho=0.8:0.88:60:0.4
438 If delay is very short, then it sound like a (metallic) robot playing music:
444 A longer delay will sound like an open air concert in the mountains:
446 aecho=0.8:0.9:1000:0.3
450 Same as above but with one more mountain:
452 aecho=0.8:0.9:1000|1800:0.3|0.25
458 Modify an audio signal according to the specified expressions.
460 This filter accepts one or more expressions (one for each channel),
461 which are evaluated and used to modify a corresponding audio signal.
463 It accepts the following parameters:
467 Set the '|'-separated expressions list for each separate channel. If
468 the number of input channels is greater than the number of
469 expressions, the last specified expression is used for the remaining
472 @item channel_layout, c
473 Set output channel layout. If not specified, the channel layout is
474 specified by the number of expressions. If set to @samp{same}, it will
475 use by default the same input channel layout.
478 Each expression in @var{exprs} can contain the following constants and functions:
482 channel number of the current expression
485 number of the evaluated sample, starting from 0
491 time of the evaluated sample expressed in seconds
494 @item nb_out_channels
495 input and output number of channels
498 the value of input channel with number @var{CH}
501 Note: this filter is slow. For faster processing you should use a
510 aeval=val(ch)/2:c=same
514 Invert phase of the second channel:
523 Apply fade-in/out effect to input audio.
525 A description of the accepted parameters follows.
529 Specify the effect type, can be either @code{in} for fade-in, or
530 @code{out} for a fade-out effect. Default is @code{in}.
532 @item start_sample, ss
533 Specify the number of the start sample for starting to apply the fade
534 effect. Default is 0.
537 Specify the number of samples for which the fade effect has to last. At
538 the end of the fade-in effect the output audio will have the same
539 volume as the input audio, at the end of the fade-out transition
540 the output audio will be silence. Default is 44100.
543 Specify the start time of the fade effect. Default is 0.
544 The value must be specified as a time duration; see
545 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
546 for the accepted syntax.
547 If set this option is used instead of @var{start_sample}.
550 Specify the duration of the fade effect. See
551 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
552 for the accepted syntax.
553 At the end of the fade-in effect the output audio will have the same
554 volume as the input audio, at the end of the fade-out transition
555 the output audio will be silence.
556 By default the duration is determined by @var{nb_samples}.
557 If set this option is used instead of @var{nb_samples}.
560 Set curve for fade transition.
562 It accepts the following values:
565 select triangular, linear slope (default)
567 select quarter of sine wave
569 select half of sine wave
571 select exponential sine wave
575 select inverted parabola
589 select inverted quarter of sine wave
591 select inverted half of sine wave
593 select double-exponential seat
595 select double-exponential sigmoid
603 Fade in first 15 seconds of audio:
609 Fade out last 25 seconds of a 900 seconds audio:
611 afade=t=out:st=875:d=25
618 Set output format constraints for the input audio. The framework will
619 negotiate the most appropriate format to minimize conversions.
621 It accepts the following parameters:
625 A '|'-separated list of requested sample formats.
628 A '|'-separated list of requested sample rates.
630 @item channel_layouts
631 A '|'-separated list of requested channel layouts.
633 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
634 for the required syntax.
637 If a parameter is omitted, all values are allowed.
639 Force the output to either unsigned 8-bit or signed 16-bit stereo
641 aformat=sample_fmts=u8|s16:channel_layouts=stereo
646 The limiter prevents input signal from raising over a desired threshold.
647 This limiter uses lookahead technology to prevent your signal from distorting.
648 It means that there is a small delay after signal is processed. Keep in mind
649 that the delay it produces is the attack time you set.
651 The filter accepts the following options:
655 Don't let signals above this level pass the limiter. The removed amplitude is
656 added automatically. Default is 1.
659 The limiter will reach its attenuation level in this amount of time in
660 milliseconds. Default is 5 milliseconds.
663 Come back from limiting to attenuation 1.0 in this amount of milliseconds.
664 Default is 50 milliseconds.
667 When gain reduction is always needed ASC takes care of releasing to an
668 average reduction level rather than reaching a reduction of 0 in the release
672 Select how much the release time is affected by ASC, 0 means nearly no changes
673 in release time while 1 produces higher release times.
676 Depending on picked setting it is recommended to upsample input 2x or 4x times
677 with @ref{aresample} before applying this filter.
681 Apply a two-pole all-pass filter with central frequency (in Hz)
682 @var{frequency}, and filter-width @var{width}.
683 An all-pass filter changes the audio's frequency to phase relationship
684 without changing its frequency to amplitude relationship.
686 The filter accepts the following options:
693 Set method to specify band-width of filter.
706 Specify the band-width of a filter in width_type units.
712 Merge two or more audio streams into a single multi-channel stream.
714 The filter accepts the following options:
719 Set the number of inputs. Default is 2.
723 If the channel layouts of the inputs are disjoint, and therefore compatible,
724 the channel layout of the output will be set accordingly and the channels
725 will be reordered as necessary. If the channel layouts of the inputs are not
726 disjoint, the output will have all the channels of the first input then all
727 the channels of the second input, in that order, and the channel layout of
728 the output will be the default value corresponding to the total number of
731 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
732 is FC+BL+BR, then the output will be in 5.1, with the channels in the
733 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
734 first input, b1 is the first channel of the second input).
736 On the other hand, if both input are in stereo, the output channels will be
737 in the default order: a1, a2, b1, b2, and the channel layout will be
738 arbitrarily set to 4.0, which may or may not be the expected value.
740 All inputs must have the same sample rate, and format.
742 If inputs do not have the same duration, the output will stop with the
749 Merge two mono files into a stereo stream:
751 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
755 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
757 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
763 Mixes multiple audio inputs into a single output.
765 Note that this filter only supports float samples (the @var{amerge}
766 and @var{pan} audio filters support many formats). If the @var{amix}
767 input has integer samples then @ref{aresample} will be automatically
768 inserted to perform the conversion to float samples.
772 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
774 will mix 3 input audio streams to a single output with the same duration as the
775 first input and a dropout transition time of 3 seconds.
777 It accepts the following parameters:
781 The number of inputs. If unspecified, it defaults to 2.
784 How to determine the end-of-stream.
788 The duration of the longest input. (default)
791 The duration of the shortest input.
794 The duration of the first input.
798 @item dropout_transition
799 The transition time, in seconds, for volume renormalization when an input
800 stream ends. The default value is 2 seconds.
806 Pass the audio source unchanged to the output.
810 Pad the end of an audio stream with silence.
812 This can be used together with @command{ffmpeg} @option{-shortest} to
813 extend audio streams to the same length as the video stream.
815 A description of the accepted options follows.
819 Set silence packet size. Default value is 4096.
822 Set the number of samples of silence to add to the end. After the
823 value is reached, the stream is terminated. This option is mutually
824 exclusive with @option{whole_len}.
827 Set the minimum total number of samples in the output audio stream. If
828 the value is longer than the input audio length, silence is added to
829 the end, until the value is reached. This option is mutually exclusive
830 with @option{pad_len}.
833 If neither the @option{pad_len} nor the @option{whole_len} option is
834 set, the filter will add silence to the end of the input stream
841 Add 1024 samples of silence to the end of the input:
847 Make sure the audio output will contain at least 10000 samples, pad
848 the input with silence if required:
854 Use @command{ffmpeg} to pad the audio input with silence, so that the
855 video stream will always result the shortest and will be converted
856 until the end in the output file when using the @option{shortest}
859 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
864 Add a phasing effect to the input audio.
866 A phaser filter creates series of peaks and troughs in the frequency spectrum.
867 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
869 A description of the accepted parameters follows.
873 Set input gain. Default is 0.4.
876 Set output gain. Default is 0.74
879 Set delay in milliseconds. Default is 3.0.
882 Set decay. Default is 0.4.
885 Set modulation speed in Hz. Default is 0.5.
888 Set modulation type. Default is triangular.
890 It accepts the following values:
900 Resample the input audio to the specified parameters, using the
901 libswresample library. If none are specified then the filter will
902 automatically convert between its input and output.
904 This filter is also able to stretch/squeeze the audio data to make it match
905 the timestamps or to inject silence / cut out audio to make it match the
906 timestamps, do a combination of both or do neither.
908 The filter accepts the syntax
909 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
910 expresses a sample rate and @var{resampler_options} is a list of
911 @var{key}=@var{value} pairs, separated by ":". See the
912 ffmpeg-resampler manual for the complete list of supported options.
918 Resample the input audio to 44100Hz:
924 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
925 samples per second compensation:
931 @section asetnsamples
933 Set the number of samples per each output audio frame.
935 The last output packet may contain a different number of samples, as
936 the filter will flush all the remaining samples when the input audio
939 The filter accepts the following options:
943 @item nb_out_samples, n
944 Set the number of frames per each output audio frame. The number is
945 intended as the number of samples @emph{per each channel}.
946 Default value is 1024.
949 If set to 1, the filter will pad the last audio frame with zeroes, so
950 that the last frame will contain the same number of samples as the
951 previous ones. Default value is 1.
954 For example, to set the number of per-frame samples to 1234 and
955 disable padding for the last frame, use:
957 asetnsamples=n=1234:p=0
962 Set the sample rate without altering the PCM data.
963 This will result in a change of speed and pitch.
965 The filter accepts the following options:
969 Set the output sample rate. Default is 44100 Hz.
974 Show a line containing various information for each input audio frame.
975 The input audio is not modified.
977 The shown line contains a sequence of key/value pairs of the form
978 @var{key}:@var{value}.
980 The following values are shown in the output:
984 The (sequential) number of the input frame, starting from 0.
987 The presentation timestamp of the input frame, in time base units; the time base
988 depends on the filter input pad, and is usually 1/@var{sample_rate}.
991 The presentation timestamp of the input frame in seconds.
994 position of the frame in the input stream, -1 if this information in
995 unavailable and/or meaningless (for example in case of synthetic audio)
1004 The sample rate for the audio frame.
1007 The number of samples (per channel) in the frame.
1010 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
1011 audio, the data is treated as if all the planes were concatenated.
1013 @item plane_checksums
1014 A list of Adler-32 checksums for each data plane.
1020 Display time domain statistical information about the audio channels.
1021 Statistics are calculated and displayed for each audio channel and,
1022 where applicable, an overall figure is also given.
1024 It accepts the following option:
1027 Short window length in seconds, used for peak and trough RMS measurement.
1028 Default is @code{0.05} (50 milliseconds). Allowed range is @code{[0.1 - 10]}.
1032 Set metadata injection. All the metadata keys are prefixed with @code{lavfi.astats.X},
1033 where @code{X} is channel number starting from 1 or string @code{Overall}. Default is
1036 Available keys for each channel are:
1067 For example full key look like this @code{lavfi.astats.1.DC_offset} or
1068 this @code{lavfi.astats.Overall.Peak_count}.
1070 For description what each key means read bellow.
1073 Set number of frame after which stats are going to be recalculated.
1074 Default is disabled.
1077 A description of each shown parameter follows:
1081 Mean amplitude displacement from zero.
1084 Minimal sample level.
1087 Maximal sample level.
1089 @item Min difference
1090 Minimal difference between two consecutive samples.
1092 @item Max difference
1093 Maximal difference between two consecutive samples.
1095 @item Mean difference
1096 Mean difference between two consecutive samples.
1097 The average of each difference between two consecutive samples.
1101 Standard peak and RMS level measured in dBFS.
1105 Peak and trough values for RMS level measured over a short window.
1108 Standard ratio of peak to RMS level (note: not in dB).
1111 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
1112 (i.e. either @var{Min level} or @var{Max level}).
1115 Number of occasions (not the number of samples) that the signal attained either
1116 @var{Min level} or @var{Max level}.
1119 Overall bit depth of audio. Number of bits used for each sample.
1122 @section astreamsync
1124 Forward two audio streams and control the order the buffers are forwarded.
1126 The filter accepts the following options:
1130 Set the expression deciding which stream should be
1131 forwarded next: if the result is negative, the first stream is forwarded; if
1132 the result is positive or zero, the second stream is forwarded. It can use
1133 the following variables:
1137 number of buffers forwarded so far on each stream
1139 number of samples forwarded so far on each stream
1141 current timestamp of each stream
1144 The default value is @code{t1-t2}, which means to always forward the stream
1145 that has a smaller timestamp.
1148 @subsection Examples
1150 Stress-test @code{amerge} by randomly sending buffers on the wrong
1151 input, while avoiding too much of a desynchronization:
1153 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
1154 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
1160 Synchronize audio data with timestamps by squeezing/stretching it and/or
1161 dropping samples/adding silence when needed.
1163 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1165 It accepts the following parameters:
1169 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1170 by default. When disabled, time gaps are covered with silence.
1173 The minimum difference between timestamps and audio data (in seconds) to trigger
1174 adding/dropping samples. The default value is 0.1. If you get an imperfect
1175 sync with this filter, try setting this parameter to 0.
1178 The maximum compensation in samples per second. Only relevant with compensate=1.
1179 The default value is 500.
1182 Assume that the first PTS should be this value. The time base is 1 / sample
1183 rate. This allows for padding/trimming at the start of the stream. By default,
1184 no assumption is made about the first frame's expected PTS, so no padding or
1185 trimming is done. For example, this could be set to 0 to pad the beginning with
1186 silence if an audio stream starts after the video stream or to trim any samples
1187 with a negative PTS due to encoder delay.
1195 The filter accepts exactly one parameter, the audio tempo. If not
1196 specified then the filter will assume nominal 1.0 tempo. Tempo must
1197 be in the [0.5, 2.0] range.
1199 @subsection Examples
1203 Slow down audio to 80% tempo:
1209 To speed up audio to 125% tempo:
1217 Trim the input so that the output contains one continuous subpart of the input.
1219 It accepts the following parameters:
1222 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1223 sample with the timestamp @var{start} will be the first sample in the output.
1226 Specify time of the first audio sample that will be dropped, i.e. the
1227 audio sample immediately preceding the one with the timestamp @var{end} will be
1228 the last sample in the output.
1231 Same as @var{start}, except this option sets the start timestamp in samples
1235 Same as @var{end}, except this option sets the end timestamp in samples instead
1239 The maximum duration of the output in seconds.
1242 The number of the first sample that should be output.
1245 The number of the first sample that should be dropped.
1248 @option{start}, @option{end}, and @option{duration} are expressed as time
1249 duration specifications; see
1250 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
1252 Note that the first two sets of the start/end options and the @option{duration}
1253 option look at the frame timestamp, while the _sample options simply count the
1254 samples that pass through the filter. So start/end_pts and start/end_sample will
1255 give different results when the timestamps are wrong, inexact or do not start at
1256 zero. Also note that this filter does not modify the timestamps. If you wish
1257 to have the output timestamps start at zero, insert the asetpts filter after the
1260 If multiple start or end options are set, this filter tries to be greedy and
1261 keep all samples that match at least one of the specified constraints. To keep
1262 only the part that matches all the constraints at once, chain multiple atrim
1265 The defaults are such that all the input is kept. So it is possible to set e.g.
1266 just the end values to keep everything before the specified time.
1271 Drop everything except the second minute of input:
1273 ffmpeg -i INPUT -af atrim=60:120
1277 Keep only the first 1000 samples:
1279 ffmpeg -i INPUT -af atrim=end_sample=1000
1286 Apply a two-pole Butterworth band-pass filter with central
1287 frequency @var{frequency}, and (3dB-point) band-width width.
1288 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1289 instead of the default: constant 0dB peak gain.
1290 The filter roll off at 6dB per octave (20dB per decade).
1292 The filter accepts the following options:
1296 Set the filter's central frequency. Default is @code{3000}.
1299 Constant skirt gain if set to 1. Defaults to 0.
1302 Set method to specify band-width of filter.
1315 Specify the band-width of a filter in width_type units.
1320 Apply a two-pole Butterworth band-reject filter with central
1321 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1322 The filter roll off at 6dB per octave (20dB per decade).
1324 The filter accepts the following options:
1328 Set the filter's central frequency. Default is @code{3000}.
1331 Set method to specify band-width of filter.
1344 Specify the band-width of a filter in width_type units.
1349 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1350 shelving filter with a response similar to that of a standard
1351 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1353 The filter accepts the following options:
1357 Give the gain at 0 Hz. Its useful range is about -20
1358 (for a large cut) to +20 (for a large boost).
1359 Beware of clipping when using a positive gain.
1362 Set the filter's central frequency and so can be used
1363 to extend or reduce the frequency range to be boosted or cut.
1364 The default value is @code{100} Hz.
1367 Set method to specify band-width of filter.
1380 Determine how steep is the filter's shelf transition.
1385 Apply a biquad IIR filter with the given coefficients.
1386 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1387 are the numerator and denominator coefficients respectively.
1390 Bauer stereo to binaural transformation, which improves headphone listening of
1391 stereo audio records.
1393 It accepts the following parameters:
1397 Pre-defined crossfeed level.
1401 Default level (fcut=700, feed=50).
1404 Chu Moy circuit (fcut=700, feed=60).
1407 Jan Meier circuit (fcut=650, feed=95).
1412 Cut frequency (in Hz).
1421 Remap input channels to new locations.
1423 It accepts the following parameters:
1425 @item channel_layout
1426 The channel layout of the output stream.
1429 Map channels from input to output. The argument is a '|'-separated list of
1430 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1431 @var{in_channel} form. @var{in_channel} can be either the name of the input
1432 channel (e.g. FL for front left) or its index in the input channel layout.
1433 @var{out_channel} is the name of the output channel or its index in the output
1434 channel layout. If @var{out_channel} is not given then it is implicitly an
1435 index, starting with zero and increasing by one for each mapping.
1438 If no mapping is present, the filter will implicitly map input channels to
1439 output channels, preserving indices.
1441 For example, assuming a 5.1+downmix input MOV file,
1443 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1445 will create an output WAV file tagged as stereo from the downmix channels of
1448 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1450 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:5.1' out.wav
1453 @section channelsplit
1455 Split each channel from an input audio stream into a separate output stream.
1457 It accepts the following parameters:
1459 @item channel_layout
1460 The channel layout of the input stream. The default is "stereo".
1463 For example, assuming a stereo input MP3 file,
1465 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1467 will create an output Matroska file with two audio streams, one containing only
1468 the left channel and the other the right channel.
1470 Split a 5.1 WAV file into per-channel files:
1472 ffmpeg -i in.wav -filter_complex
1473 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1474 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1475 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1480 Add a chorus effect to the audio.
1482 Can make a single vocal sound like a chorus, but can also be applied to instrumentation.
1484 Chorus resembles an echo effect with a short delay, but whereas with echo the delay is
1485 constant, with chorus, it is varied using using sinusoidal or triangular modulation.
1486 The modulation depth defines the range the modulated delay is played before or after
1487 the delay. Hence the delayed sound will sound slower or faster, that is the delayed
1488 sound tuned around the original one, like in a chorus where some vocals are slightly
1491 It accepts the following parameters:
1494 Set input gain. Default is 0.4.
1497 Set output gain. Default is 0.4.
1500 Set delays. A typical delay is around 40ms to 60ms.
1512 @subsection Examples
1518 chorus=0.7:0.9:55:0.4:0.25:2
1524 chorus=0.6:0.9:50|60:0.4|0.32:0.25|0.4:2|1.3
1528 Fuller sounding chorus with three delays:
1530 chorus=0.5:0.9:50|60|40:0.4|0.32|0.3:0.25|0.4|0.3:2|2.3|1.3
1535 Compress or expand the audio's dynamic range.
1537 It accepts the following parameters:
1543 A list of times in seconds for each channel over which the instantaneous level
1544 of the input signal is averaged to determine its volume. @var{attacks} refers to
1545 increase of volume and @var{decays} refers to decrease of volume. For most
1546 situations, the attack time (response to the audio getting louder) should be
1547 shorter than the decay time, because the human ear is more sensitive to sudden
1548 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1549 a typical value for decay is 0.8 seconds.
1550 If specified number of attacks & decays is lower than number of channels, the last
1551 set attack/decay will be used for all remaining channels.
1554 A list of points for the transfer function, specified in dB relative to the
1555 maximum possible signal amplitude. Each key points list must be defined using
1556 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1557 @code{x0/y0 x1/y1 x2/y2 ....}
1559 The input values must be in strictly increasing order but the transfer function
1560 does not have to be monotonically rising. The point @code{0/0} is assumed but
1561 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1562 function are @code{-70/-70|-60/-20}.
1565 Set the curve radius in dB for all joints. It defaults to 0.01.
1568 Set the additional gain in dB to be applied at all points on the transfer
1569 function. This allows for easy adjustment of the overall gain.
1573 Set an initial volume, in dB, to be assumed for each channel when filtering
1574 starts. This permits the user to supply a nominal level initially, so that, for
1575 example, a very large gain is not applied to initial signal levels before the
1576 companding has begun to operate. A typical value for audio which is initially
1577 quiet is -90 dB. It defaults to 0.
1580 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1581 delayed before being fed to the volume adjuster. Specifying a delay
1582 approximately equal to the attack/decay times allows the filter to effectively
1583 operate in predictive rather than reactive mode. It defaults to 0.
1587 @subsection Examples
1591 Make music with both quiet and loud passages suitable for listening to in a
1594 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1597 Another example for audio with whisper and explosion parts:
1599 compand=0|0:1|1:-90/-900|-70/-70|-30/-9|0/-3:6:0:0:0
1603 A noise gate for when the noise is at a lower level than the signal:
1605 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1609 Here is another noise gate, this time for when the noise is at a higher level
1610 than the signal (making it, in some ways, similar to squelch):
1612 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1617 Apply a DC shift to the audio.
1619 This can be useful to remove a DC offset (caused perhaps by a hardware problem
1620 in the recording chain) from the audio. The effect of a DC offset is reduced
1621 headroom and hence volume. The @ref{astats} filter can be used to determine if
1622 a signal has a DC offset.
1626 Set the DC shift, allowed range is [-1, 1]. It indicates the amount to shift
1630 Optional. It should have a value much less than 1 (e.g. 0.05 or 0.02) and is
1631 used to prevent clipping.
1635 Dynamic Audio Normalizer.
1637 This filter applies a certain amount of gain to the input audio in order
1638 to bring its peak magnitude to a target level (e.g. 0 dBFS). However, in
1639 contrast to more "simple" normalization algorithms, the Dynamic Audio
1640 Normalizer *dynamically* re-adjusts the gain factor to the input audio.
1641 This allows for applying extra gain to the "quiet" sections of the audio
1642 while avoiding distortions or clipping the "loud" sections. In other words:
1643 The Dynamic Audio Normalizer will "even out" the volume of quiet and loud
1644 sections, in the sense that the volume of each section is brought to the
1645 same target level. Note, however, that the Dynamic Audio Normalizer achieves
1646 this goal *without* applying "dynamic range compressing". It will retain 100%
1647 of the dynamic range *within* each section of the audio file.
1651 Set the frame length in milliseconds. In range from 10 to 8000 milliseconds.
1652 Default is 500 milliseconds.
1653 The Dynamic Audio Normalizer processes the input audio in small chunks,
1654 referred to as frames. This is required, because a peak magnitude has no
1655 meaning for just a single sample value. Instead, we need to determine the
1656 peak magnitude for a contiguous sequence of sample values. While a "standard"
1657 normalizer would simply use the peak magnitude of the complete file, the
1658 Dynamic Audio Normalizer determines the peak magnitude individually for each
1659 frame. The length of a frame is specified in milliseconds. By default, the
1660 Dynamic Audio Normalizer uses a frame length of 500 milliseconds, which has
1661 been found to give good results with most files.
1662 Note that the exact frame length, in number of samples, will be determined
1663 automatically, based on the sampling rate of the individual input audio file.
1666 Set the Gaussian filter window size. In range from 3 to 301, must be odd
1667 number. Default is 31.
1668 Probably the most important parameter of the Dynamic Audio Normalizer is the
1669 @code{window size} of the Gaussian smoothing filter. The filter's window size
1670 is specified in frames, centered around the current frame. For the sake of
1671 simplicity, this must be an odd number. Consequently, the default value of 31
1672 takes into account the current frame, as well as the 15 preceding frames and
1673 the 15 subsequent frames. Using a larger window results in a stronger
1674 smoothing effect and thus in less gain variation, i.e. slower gain
1675 adaptation. Conversely, using a smaller window results in a weaker smoothing
1676 effect and thus in more gain variation, i.e. faster gain adaptation.
1677 In other words, the more you increase this value, the more the Dynamic Audio
1678 Normalizer will behave like a "traditional" normalization filter. On the
1679 contrary, the more you decrease this value, the more the Dynamic Audio
1680 Normalizer will behave like a dynamic range compressor.
1683 Set the target peak value. This specifies the highest permissible magnitude
1684 level for the normalized audio input. This filter will try to approach the
1685 target peak magnitude as closely as possible, but at the same time it also
1686 makes sure that the normalized signal will never exceed the peak magnitude.
1687 A frame's maximum local gain factor is imposed directly by the target peak
1688 magnitude. The default value is 0.95 and thus leaves a headroom of 5%*.
1689 It is not recommended to go above this value.
1692 Set the maximum gain factor. In range from 1.0 to 100.0. Default is 10.0.
1693 The Dynamic Audio Normalizer determines the maximum possible (local) gain
1694 factor for each input frame, i.e. the maximum gain factor that does not
1695 result in clipping or distortion. The maximum gain factor is determined by
1696 the frame's highest magnitude sample. However, the Dynamic Audio Normalizer
1697 additionally bounds the frame's maximum gain factor by a predetermined
1698 (global) maximum gain factor. This is done in order to avoid excessive gain
1699 factors in "silent" or almost silent frames. By default, the maximum gain
1700 factor is 10.0, For most inputs the default value should be sufficient and
1701 it usually is not recommended to increase this value. Though, for input
1702 with an extremely low overall volume level, it may be necessary to allow even
1703 higher gain factors. Note, however, that the Dynamic Audio Normalizer does
1704 not simply apply a "hard" threshold (i.e. cut off values above the threshold).
1705 Instead, a "sigmoid" threshold function will be applied. This way, the
1706 gain factors will smoothly approach the threshold value, but never exceed that
1710 Set the target RMS. In range from 0.0 to 1.0. Default is 0.0 - disabled.
1711 By default, the Dynamic Audio Normalizer performs "peak" normalization.
1712 This means that the maximum local gain factor for each frame is defined
1713 (only) by the frame's highest magnitude sample. This way, the samples can
1714 be amplified as much as possible without exceeding the maximum signal
1715 level, i.e. without clipping. Optionally, however, the Dynamic Audio
1716 Normalizer can also take into account the frame's root mean square,
1717 abbreviated RMS. In electrical engineering, the RMS is commonly used to
1718 determine the power of a time-varying signal. It is therefore considered
1719 that the RMS is a better approximation of the "perceived loudness" than
1720 just looking at the signal's peak magnitude. Consequently, by adjusting all
1721 frames to a constant RMS value, a uniform "perceived loudness" can be
1722 established. If a target RMS value has been specified, a frame's local gain
1723 factor is defined as the factor that would result in exactly that RMS value.
1724 Note, however, that the maximum local gain factor is still restricted by the
1725 frame's highest magnitude sample, in order to prevent clipping.
1728 Enable channels coupling. By default is enabled.
1729 By default, the Dynamic Audio Normalizer will amplify all channels by the same
1730 amount. This means the same gain factor will be applied to all channels, i.e.
1731 the maximum possible gain factor is determined by the "loudest" channel.
1732 However, in some recordings, it may happen that the volume of the different
1733 channels is uneven, e.g. one channel may be "quieter" than the other one(s).
1734 In this case, this option can be used to disable the channel coupling. This way,
1735 the gain factor will be determined independently for each channel, depending
1736 only on the individual channel's highest magnitude sample. This allows for
1737 harmonizing the volume of the different channels.
1740 Enable DC bias correction. By default is disabled.
1741 An audio signal (in the time domain) is a sequence of sample values.
1742 In the Dynamic Audio Normalizer these sample values are represented in the
1743 -1.0 to 1.0 range, regardless of the original input format. Normally, the
1744 audio signal, or "waveform", should be centered around the zero point.
1745 That means if we calculate the mean value of all samples in a file, or in a
1746 single frame, then the result should be 0.0 or at least very close to that
1747 value. If, however, there is a significant deviation of the mean value from
1748 0.0, in either positive or negative direction, this is referred to as a
1749 DC bias or DC offset. Since a DC bias is clearly undesirable, the Dynamic
1750 Audio Normalizer provides optional DC bias correction.
1751 With DC bias correction enabled, the Dynamic Audio Normalizer will determine
1752 the mean value, or "DC correction" offset, of each input frame and subtract
1753 that value from all of the frame's sample values which ensures those samples
1754 are centered around 0.0 again. Also, in order to avoid "gaps" at the frame
1755 boundaries, the DC correction offset values will be interpolated smoothly
1756 between neighbouring frames.
1759 Enable alternative boundary mode. By default is disabled.
1760 The Dynamic Audio Normalizer takes into account a certain neighbourhood
1761 around each frame. This includes the preceding frames as well as the
1762 subsequent frames. However, for the "boundary" frames, located at the very
1763 beginning and at the very end of the audio file, not all neighbouring
1764 frames are available. In particular, for the first few frames in the audio
1765 file, the preceding frames are not known. And, similarly, for the last few
1766 frames in the audio file, the subsequent frames are not known. Thus, the
1767 question arises which gain factors should be assumed for the missing frames
1768 in the "boundary" region. The Dynamic Audio Normalizer implements two modes
1769 to deal with this situation. The default boundary mode assumes a gain factor
1770 of exactly 1.0 for the missing frames, resulting in a smooth "fade in" and
1771 "fade out" at the beginning and at the end of the input, respectively.
1774 Set the compress factor. In range from 0.0 to 30.0. Default is 0.0.
1775 By default, the Dynamic Audio Normalizer does not apply "traditional"
1776 compression. This means that signal peaks will not be pruned and thus the
1777 full dynamic range will be retained within each local neighbourhood. However,
1778 in some cases it may be desirable to combine the Dynamic Audio Normalizer's
1779 normalization algorithm with a more "traditional" compression.
1780 For this purpose, the Dynamic Audio Normalizer provides an optional compression
1781 (thresholding) function. If (and only if) the compression feature is enabled,
1782 all input frames will be processed by a soft knee thresholding function prior
1783 to the actual normalization process. Put simply, the thresholding function is
1784 going to prune all samples whose magnitude exceeds a certain threshold value.
1785 However, the Dynamic Audio Normalizer does not simply apply a fixed threshold
1786 value. Instead, the threshold value will be adjusted for each individual
1788 In general, smaller parameters result in stronger compression, and vice versa.
1789 Values below 3.0 are not recommended, because audible distortion may appear.
1794 Make audio easier to listen to on headphones.
1796 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1797 so that when listened to on headphones the stereo image is moved from
1798 inside your head (standard for headphones) to outside and in front of
1799 the listener (standard for speakers).
1805 Apply a two-pole peaking equalisation (EQ) filter. With this
1806 filter, the signal-level at and around a selected frequency can
1807 be increased or decreased, whilst (unlike bandpass and bandreject
1808 filters) that at all other frequencies is unchanged.
1810 In order to produce complex equalisation curves, this filter can
1811 be given several times, each with a different central frequency.
1813 The filter accepts the following options:
1817 Set the filter's central frequency in Hz.
1820 Set method to specify band-width of filter.
1833 Specify the band-width of a filter in width_type units.
1836 Set the required gain or attenuation in dB.
1837 Beware of clipping when using a positive gain.
1840 @subsection Examples
1843 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1845 equalizer=f=1000:width_type=h:width=200:g=-10
1849 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1851 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1855 @section extrastereo
1857 Linearly increases the difference between left and right channels which
1858 adds some sort of "live" effect to playback.
1860 The filter accepts the following option:
1864 Sets the difference coefficient (default: 2.5). 0.0 means mono sound
1865 (average of both channels), with 1.0 sound will be unchanged, with
1866 -1.0 left and right channels will be swapped.
1869 Enable clipping. By default is enabled.
1873 Apply a flanging effect to the audio.
1875 The filter accepts the following options:
1879 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
1882 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
1885 Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
1889 Set percentage of delayed signal mixed with original. Range from 0 to 100.
1890 Default value is 71.
1893 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
1896 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
1897 Default value is @var{sinusoidal}.
1900 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
1901 Default value is 25.
1904 Set delay-line interpolation, @var{linear} or @var{quadratic}.
1905 Default is @var{linear}.
1910 Apply a high-pass filter with 3dB point frequency.
1911 The filter can be either single-pole, or double-pole (the default).
1912 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1914 The filter accepts the following options:
1918 Set frequency in Hz. Default is 3000.
1921 Set number of poles. Default is 2.
1924 Set method to specify band-width of filter.
1937 Specify the band-width of a filter in width_type units.
1938 Applies only to double-pole filter.
1939 The default is 0.707q and gives a Butterworth response.
1944 Join multiple input streams into one multi-channel stream.
1946 It accepts the following parameters:
1950 The number of input streams. It defaults to 2.
1952 @item channel_layout
1953 The desired output channel layout. It defaults to stereo.
1956 Map channels from inputs to output. The argument is a '|'-separated list of
1957 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1958 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1959 can be either the name of the input channel (e.g. FL for front left) or its
1960 index in the specified input stream. @var{out_channel} is the name of the output
1964 The filter will attempt to guess the mappings when they are not specified
1965 explicitly. It does so by first trying to find an unused matching input channel
1966 and if that fails it picks the first unused input channel.
1968 Join 3 inputs (with properly set channel layouts):
1970 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1973 Build a 5.1 output from 6 single-channel streams:
1975 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1976 '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'
1982 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1984 To enable compilation of this filter you need to configure FFmpeg with
1985 @code{--enable-ladspa}.
1989 Specifies the name of LADSPA plugin library to load. If the environment
1990 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1991 each one of the directories specified by the colon separated list in
1992 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1993 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1994 @file{/usr/lib/ladspa/}.
1997 Specifies the plugin within the library. Some libraries contain only
1998 one plugin, but others contain many of them. If this is not set filter
1999 will list all available plugins within the specified library.
2002 Set the '|' separated list of controls which are zero or more floating point
2003 values that determine the behavior of the loaded plugin (for example delay,
2005 Controls need to be defined using the following syntax:
2006 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
2007 @var{valuei} is the value set on the @var{i}-th control.
2008 Alternatively they can be also defined using the following syntax:
2009 @var{value0}|@var{value1}|@var{value2}|..., where
2010 @var{valuei} is the value set on the @var{i}-th control.
2011 If @option{controls} is set to @code{help}, all available controls and
2012 their valid ranges are printed.
2014 @item sample_rate, s
2015 Specify the sample rate, default to 44100. Only used if plugin have
2019 Set the number of samples per channel per each output frame, default
2020 is 1024. Only used if plugin have zero inputs.
2023 Set the minimum duration of the sourced audio. See
2024 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2025 for the accepted syntax.
2026 Note that the resulting duration may be greater than the specified duration,
2027 as the generated audio is always cut at the end of a complete frame.
2028 If not specified, or the expressed duration is negative, the audio is
2029 supposed to be generated forever.
2030 Only used if plugin have zero inputs.
2034 @subsection Examples
2038 List all available plugins within amp (LADSPA example plugin) library:
2044 List all available controls and their valid ranges for @code{vcf_notch}
2045 plugin from @code{VCF} library:
2047 ladspa=f=vcf:p=vcf_notch:c=help
2051 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
2054 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
2058 Add reverberation to the audio using TAP-plugins
2059 (Tom's Audio Processing plugins):
2061 ladspa=file=tap_reverb:tap_reverb
2065 Generate white noise, with 0.2 amplitude:
2067 ladspa=file=cmt:noise_source_white:c=c0=.2
2071 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
2072 @code{C* Audio Plugin Suite} (CAPS) library:
2074 ladspa=file=caps:Click:c=c1=20'
2078 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
2080 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
2084 @subsection Commands
2086 This filter supports the following commands:
2089 Modify the @var{N}-th control value.
2091 If the specified value is not valid, it is ignored and prior one is kept.
2096 Apply a low-pass filter with 3dB point frequency.
2097 The filter can be either single-pole or double-pole (the default).
2098 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2100 The filter accepts the following options:
2104 Set frequency in Hz. Default is 500.
2107 Set number of poles. Default is 2.
2110 Set method to specify band-width of filter.
2123 Specify the band-width of a filter in width_type units.
2124 Applies only to double-pole filter.
2125 The default is 0.707q and gives a Butterworth response.
2131 Mix channels with specific gain levels. The filter accepts the output
2132 channel layout followed by a set of channels definitions.
2134 This filter is also designed to efficiently remap the channels of an audio
2137 The filter accepts parameters of the form:
2138 "@var{l}|@var{outdef}|@var{outdef}|..."
2142 output channel layout or number of channels
2145 output channel specification, of the form:
2146 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
2149 output channel to define, either a channel name (FL, FR, etc.) or a channel
2150 number (c0, c1, etc.)
2153 multiplicative coefficient for the channel, 1 leaving the volume unchanged
2156 input channel to use, see out_name for details; it is not possible to mix
2157 named and numbered input channels
2160 If the `=' in a channel specification is replaced by `<', then the gains for
2161 that specification will be renormalized so that the total is 1, thus
2162 avoiding clipping noise.
2164 @subsection Mixing examples
2166 For example, if you want to down-mix from stereo to mono, but with a bigger
2167 factor for the left channel:
2169 pan=1c|c0=0.9*c0+0.1*c1
2172 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
2173 7-channels surround:
2175 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
2178 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
2179 that should be preferred (see "-ac" option) unless you have very specific
2182 @subsection Remapping examples
2184 The channel remapping will be effective if, and only if:
2187 @item gain coefficients are zeroes or ones,
2188 @item only one input per channel output,
2191 If all these conditions are satisfied, the filter will notify the user ("Pure
2192 channel mapping detected"), and use an optimized and lossless method to do the
2195 For example, if you have a 5.1 source and want a stereo audio stream by
2196 dropping the extra channels:
2198 pan="stereo| c0=FL | c1=FR"
2201 Given the same source, you can also switch front left and front right channels
2202 and keep the input channel layout:
2204 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
2207 If the input is a stereo audio stream, you can mute the front left channel (and
2208 still keep the stereo channel layout) with:
2213 Still with a stereo audio stream input, you can copy the right channel in both
2214 front left and right:
2216 pan="stereo| c0=FR | c1=FR"
2221 ReplayGain scanner filter. This filter takes an audio stream as an input and
2222 outputs it unchanged.
2223 At end of filtering it displays @code{track_gain} and @code{track_peak}.
2227 Convert the audio sample format, sample rate and channel layout. It is
2228 not meant to be used directly.
2230 @section sidechaincompress
2232 This filter acts like normal compressor but has the ability to compress
2233 detected signal using second input signal.
2234 It needs two input streams and returns one output stream.
2235 First input stream will be processed depending on second stream signal.
2236 The filtered signal then can be filtered with other filters in later stages of
2237 processing. See @ref{pan} and @ref{amerge} filter.
2239 The filter accepts the following options:
2243 If a signal of second stream raises above this level it will affect the gain
2244 reduction of first stream.
2245 By default is 0.125. Range is between 0.00097563 and 1.
2248 Set a ratio about which the signal is reduced. 1:2 means that if the level
2249 raised 4dB above the threshold, it will be only 2dB above after the reduction.
2250 Default is 2. Range is between 1 and 20.
2253 Amount of milliseconds the signal has to rise above the threshold before gain
2254 reduction starts. Default is 20. Range is between 0.01 and 2000.
2257 Amount of milliseconds the signal has to fall bellow the threshold before
2258 reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
2261 Set the amount by how much signal will be amplified after processing.
2262 Default is 2. Range is from 1 and 64.
2265 Curve the sharp knee around the threshold to enter gain reduction more softly.
2266 Default is 2.82843. Range is between 1 and 8.
2269 Choose if the @code{average} level between all channels of side-chain stream
2270 or the louder(@code{maximum}) channel of side-chain stream affects the
2271 reduction. Default is @code{average}.
2274 Should the exact signal be taken in case of @code{peak} or an RMS one in case
2275 of @code{rms}. Default is @code{rms} which is mainly smoother.
2278 @subsection Examples
2282 Full ffmpeg example taking 2 audio inputs, 1st input to be compressed
2283 depending on the signal of 2nd input and later compressed signal to be
2284 merged with 2nd input:
2286 ffmpeg -i main.flac -i sidechain.flac -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress[compr];[compr][mix]amerge"
2290 @section silencedetect
2292 Detect silence in an audio stream.
2294 This filter logs a message when it detects that the input audio volume is less
2295 or equal to a noise tolerance value for a duration greater or equal to the
2296 minimum detected noise duration.
2298 The printed times and duration are expressed in seconds.
2300 The filter accepts the following options:
2304 Set silence duration until notification (default is 2 seconds).
2307 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
2308 specified value) or amplitude ratio. Default is -60dB, or 0.001.
2311 @subsection Examples
2315 Detect 5 seconds of silence with -50dB noise tolerance:
2317 silencedetect=n=-50dB:d=5
2321 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
2322 tolerance in @file{silence.mp3}:
2324 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
2328 @section silenceremove
2330 Remove silence from the beginning, middle or end of the audio.
2332 The filter accepts the following options:
2336 This value is used to indicate if audio should be trimmed at beginning of
2337 the audio. A value of zero indicates no silence should be trimmed from the
2338 beginning. When specifying a non-zero value, it trims audio up until it
2339 finds non-silence. Normally, when trimming silence from beginning of audio
2340 the @var{start_periods} will be @code{1} but it can be increased to higher
2341 values to trim all audio up to specific count of non-silence periods.
2342 Default value is @code{0}.
2344 @item start_duration
2345 Specify the amount of time that non-silence must be detected before it stops
2346 trimming audio. By increasing the duration, bursts of noises can be treated
2347 as silence and trimmed off. Default value is @code{0}.
2349 @item start_threshold
2350 This indicates what sample value should be treated as silence. For digital
2351 audio, a value of @code{0} may be fine but for audio recorded from analog,
2352 you may wish to increase the value to account for background noise.
2353 Can be specified in dB (in case "dB" is appended to the specified value)
2354 or amplitude ratio. Default value is @code{0}.
2357 Set the count for trimming silence from the end of audio.
2358 To remove silence from the middle of a file, specify a @var{stop_periods}
2359 that is negative. This value is then treated as a positive value and is
2360 used to indicate the effect should restart processing as specified by
2361 @var{start_periods}, making it suitable for removing periods of silence
2362 in the middle of the audio.
2363 Default value is @code{0}.
2366 Specify a duration of silence that must exist before audio is not copied any
2367 more. By specifying a higher duration, silence that is wanted can be left in
2369 Default value is @code{0}.
2371 @item stop_threshold
2372 This is the same as @option{start_threshold} but for trimming silence from
2374 Can be specified in dB (in case "dB" is appended to the specified value)
2375 or amplitude ratio. Default value is @code{0}.
2378 This indicate that @var{stop_duration} length of audio should be left intact
2379 at the beginning of each period of silence.
2380 For example, if you want to remove long pauses between words but do not want
2381 to remove the pauses completely. Default value is @code{0}.
2385 @subsection Examples
2389 The following example shows how this filter can be used to start a recording
2390 that does not contain the delay at the start which usually occurs between
2391 pressing the record button and the start of the performance:
2393 silenceremove=1:5:0.02
2397 @section stereowiden
2399 This filter enhance the stereo effect by suppressing signal common to both
2400 channels and by delaying the signal of left into right and vice versa,
2401 thereby widening the stereo effect.
2403 The filter accepts the following options:
2407 Time in milliseconds of the delay of left signal into right and vice versa.
2408 Default is 20 milliseconds.
2411 Amount of gain in delayed signal into right and vice versa. Gives a delay
2412 effect of left signal in right output and vice versa which gives widening
2413 effect. Default is 0.3.
2416 Cross feed of left into right with inverted phase. This helps in suppressing
2417 the mono. If the value is 1 it will cancel all the signal common to both
2418 channels. Default is 0.3.
2421 Set level of input signal of original channel. Default is 0.8.
2426 Boost or cut treble (upper) frequencies of the audio using a two-pole
2427 shelving filter with a response similar to that of a standard
2428 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
2430 The filter accepts the following options:
2434 Give the gain at whichever is the lower of ~22 kHz and the
2435 Nyquist frequency. Its useful range is about -20 (for a large cut)
2436 to +20 (for a large boost). Beware of clipping when using a positive gain.
2439 Set the filter's central frequency and so can be used
2440 to extend or reduce the frequency range to be boosted or cut.
2441 The default value is @code{3000} Hz.
2444 Set method to specify band-width of filter.
2457 Determine how steep is the filter's shelf transition.
2462 Adjust the input audio volume.
2464 It accepts the following parameters:
2468 Set audio volume expression.
2470 Output values are clipped to the maximum value.
2472 The output audio volume is given by the relation:
2474 @var{output_volume} = @var{volume} * @var{input_volume}
2477 The default value for @var{volume} is "1.0".
2480 This parameter represents the mathematical precision.
2482 It determines which input sample formats will be allowed, which affects the
2483 precision of the volume scaling.
2487 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
2489 32-bit floating-point; this limits input sample format to FLT. (default)
2491 64-bit floating-point; this limits input sample format to DBL.
2495 Choose the behaviour on encountering ReplayGain side data in input frames.
2499 Remove ReplayGain side data, ignoring its contents (the default).
2502 Ignore ReplayGain side data, but leave it in the frame.
2505 Prefer the track gain, if present.
2508 Prefer the album gain, if present.
2511 @item replaygain_preamp
2512 Pre-amplification gain in dB to apply to the selected replaygain gain.
2514 Default value for @var{replaygain_preamp} is 0.0.
2517 Set when the volume expression is evaluated.
2519 It accepts the following values:
2522 only evaluate expression once during the filter initialization, or
2523 when the @samp{volume} command is sent
2526 evaluate expression for each incoming frame
2529 Default value is @samp{once}.
2532 The volume expression can contain the following parameters.
2536 frame number (starting at zero)
2539 @item nb_consumed_samples
2540 number of samples consumed by the filter
2542 number of samples in the current frame
2544 original frame position in the file
2550 PTS at start of stream
2552 time at start of stream
2558 last set volume value
2561 Note that when @option{eval} is set to @samp{once} only the
2562 @var{sample_rate} and @var{tb} variables are available, all other
2563 variables will evaluate to NAN.
2565 @subsection Commands
2567 This filter supports the following commands:
2570 Modify the volume expression.
2571 The command accepts the same syntax of the corresponding option.
2573 If the specified expression is not valid, it is kept at its current
2575 @item replaygain_noclip
2576 Prevent clipping by limiting the gain applied.
2578 Default value for @var{replaygain_noclip} is 1.
2582 @subsection Examples
2586 Halve the input audio volume:
2590 volume=volume=-6.0206dB
2593 In all the above example the named key for @option{volume} can be
2594 omitted, for example like in:
2600 Increase input audio power by 6 decibels using fixed-point precision:
2602 volume=volume=6dB:precision=fixed
2606 Fade volume after time 10 with an annihilation period of 5 seconds:
2608 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
2612 @section volumedetect
2614 Detect the volume of the input video.
2616 The filter has no parameters. The input is not modified. Statistics about
2617 the volume will be printed in the log when the input stream end is reached.
2619 In particular it will show the mean volume (root mean square), maximum
2620 volume (on a per-sample basis), and the beginning of a histogram of the
2621 registered volume values (from the maximum value to a cumulated 1/1000 of
2624 All volumes are in decibels relative to the maximum PCM value.
2626 @subsection Examples
2628 Here is an excerpt of the output:
2630 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2631 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2632 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2633 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2634 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2635 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2636 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2637 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2638 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2644 The mean square energy is approximately -27 dB, or 10^-2.7.
2646 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2648 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2651 In other words, raising the volume by +4 dB does not cause any clipping,
2652 raising it by +5 dB causes clipping for 6 samples, etc.
2654 @c man end AUDIO FILTERS
2656 @chapter Audio Sources
2657 @c man begin AUDIO SOURCES
2659 Below is a description of the currently available audio sources.
2663 Buffer audio frames, and make them available to the filter chain.
2665 This source is mainly intended for a programmatic use, in particular
2666 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2668 It accepts the following parameters:
2672 The timebase which will be used for timestamps of submitted frames. It must be
2673 either a floating-point number or in @var{numerator}/@var{denominator} form.
2676 The sample rate of the incoming audio buffers.
2679 The sample format of the incoming audio buffers.
2680 Either a sample format name or its corresponding integer representation from
2681 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2683 @item channel_layout
2684 The channel layout of the incoming audio buffers.
2685 Either a channel layout name from channel_layout_map in
2686 @file{libavutil/channel_layout.c} or its corresponding integer representation
2687 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2690 The number of channels of the incoming audio buffers.
2691 If both @var{channels} and @var{channel_layout} are specified, then they
2696 @subsection Examples
2699 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2702 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2703 Since the sample format with name "s16p" corresponds to the number
2704 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2707 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2712 Generate an audio signal specified by an expression.
2714 This source accepts in input one or more expressions (one for each
2715 channel), which are evaluated and used to generate a corresponding
2718 This source accepts the following options:
2722 Set the '|'-separated expressions list for each separate channel. In case the
2723 @option{channel_layout} option is not specified, the selected channel layout
2724 depends on the number of provided expressions. Otherwise the last
2725 specified expression is applied to the remaining output channels.
2727 @item channel_layout, c
2728 Set the channel layout. The number of channels in the specified layout
2729 must be equal to the number of specified expressions.
2732 Set the minimum duration of the sourced audio. See
2733 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2734 for the accepted syntax.
2735 Note that the resulting duration may be greater than the specified
2736 duration, as the generated audio is always cut at the end of a
2739 If not specified, or the expressed duration is negative, the audio is
2740 supposed to be generated forever.
2743 Set the number of samples per channel per each output frame,
2746 @item sample_rate, s
2747 Specify the sample rate, default to 44100.
2750 Each expression in @var{exprs} can contain the following constants:
2754 number of the evaluated sample, starting from 0
2757 time of the evaluated sample expressed in seconds, starting from 0
2764 @subsection Examples
2774 Generate a sin signal with frequency of 440 Hz, set sample rate to
2777 aevalsrc="sin(440*2*PI*t):s=8000"
2781 Generate a two channels signal, specify the channel layout (Front
2782 Center + Back Center) explicitly:
2784 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2788 Generate white noise:
2790 aevalsrc="-2+random(0)"
2794 Generate an amplitude modulated signal:
2796 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2800 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2802 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2809 The null audio source, return unprocessed audio frames. It is mainly useful
2810 as a template and to be employed in analysis / debugging tools, or as
2811 the source for filters which ignore the input data (for example the sox
2814 This source accepts the following options:
2818 @item channel_layout, cl
2820 Specifies the channel layout, and can be either an integer or a string
2821 representing a channel layout. The default value of @var{channel_layout}
2824 Check the channel_layout_map definition in
2825 @file{libavutil/channel_layout.c} for the mapping between strings and
2826 channel layout values.
2828 @item sample_rate, r
2829 Specifies the sample rate, and defaults to 44100.
2832 Set the number of samples per requested frames.
2836 @subsection Examples
2840 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2842 anullsrc=r=48000:cl=4
2846 Do the same operation with a more obvious syntax:
2848 anullsrc=r=48000:cl=mono
2852 All the parameters need to be explicitly defined.
2856 Synthesize a voice utterance using the libflite library.
2858 To enable compilation of this filter you need to configure FFmpeg with
2859 @code{--enable-libflite}.
2861 Note that the flite library is not thread-safe.
2863 The filter accepts the following options:
2868 If set to 1, list the names of the available voices and exit
2869 immediately. Default value is 0.
2872 Set the maximum number of samples per frame. Default value is 512.
2875 Set the filename containing the text to speak.
2878 Set the text to speak.
2881 Set the voice to use for the speech synthesis. Default value is
2882 @code{kal}. See also the @var{list_voices} option.
2885 @subsection Examples
2889 Read from file @file{speech.txt}, and synthesize the text using the
2890 standard flite voice:
2892 flite=textfile=speech.txt
2896 Read the specified text selecting the @code{slt} voice:
2898 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2902 Input text to ffmpeg:
2904 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2908 Make @file{ffplay} speak the specified text, using @code{flite} and
2909 the @code{lavfi} device:
2911 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2915 For more information about libflite, check:
2916 @url{http://www.speech.cs.cmu.edu/flite/}
2920 Generate an audio signal made of a sine wave with amplitude 1/8.
2922 The audio signal is bit-exact.
2924 The filter accepts the following options:
2929 Set the carrier frequency. Default is 440 Hz.
2931 @item beep_factor, b
2932 Enable a periodic beep every second with frequency @var{beep_factor} times
2933 the carrier frequency. Default is 0, meaning the beep is disabled.
2935 @item sample_rate, r
2936 Specify the sample rate, default is 44100.
2939 Specify the duration of the generated audio stream.
2941 @item samples_per_frame
2942 Set the number of samples per output frame.
2944 The expression can contain the following constants:
2948 The (sequential) number of the output audio frame, starting from 0.
2951 The PTS (Presentation TimeStamp) of the output audio frame,
2952 expressed in @var{TB} units.
2955 The PTS of the output audio frame, expressed in seconds.
2958 The timebase of the output audio frames.
2961 Default is @code{1024}.
2964 @subsection Examples
2969 Generate a simple 440 Hz sine wave:
2975 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2979 sine=frequency=220:beep_factor=4:duration=5
2983 Generate a 1 kHz sine wave following @code{1602,1601,1602,1601,1602} NTSC
2986 sine=1000:samples_per_frame='st(0,mod(n,5)); 1602-not(not(eq(ld(0),1)+eq(ld(0),3)))'
2990 @c man end AUDIO SOURCES
2992 @chapter Audio Sinks
2993 @c man begin AUDIO SINKS
2995 Below is a description of the currently available audio sinks.
2997 @section abuffersink
2999 Buffer audio frames, and make them available to the end of filter chain.
3001 This sink is mainly intended for programmatic use, in particular
3002 through the interface defined in @file{libavfilter/buffersink.h}
3003 or the options system.
3005 It accepts a pointer to an AVABufferSinkContext structure, which
3006 defines the incoming buffers' formats, to be passed as the opaque
3007 parameter to @code{avfilter_init_filter} for initialization.
3010 Null audio sink; do absolutely nothing with the input audio. It is
3011 mainly useful as a template and for use in analysis / debugging
3014 @c man end AUDIO SINKS
3016 @chapter Video Filters
3017 @c man begin VIDEO FILTERS
3019 When you configure your FFmpeg build, you can disable any of the
3020 existing filters using @code{--disable-filters}.
3021 The configure output will show the video filters included in your
3024 Below is a description of the currently available video filters.
3026 @section alphaextract
3028 Extract the alpha component from the input as a grayscale video. This
3029 is especially useful with the @var{alphamerge} filter.
3033 Add or replace the alpha component of the primary input with the
3034 grayscale value of a second input. This is intended for use with
3035 @var{alphaextract} to allow the transmission or storage of frame
3036 sequences that have alpha in a format that doesn't support an alpha
3039 For example, to reconstruct full frames from a normal YUV-encoded video
3040 and a separate video created with @var{alphaextract}, you might use:
3042 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
3045 Since this filter is designed for reconstruction, it operates on frame
3046 sequences without considering timestamps, and terminates when either
3047 input reaches end of stream. This will cause problems if your encoding
3048 pipeline drops frames. If you're trying to apply an image as an
3049 overlay to a video stream, consider the @var{overlay} filter instead.
3053 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
3054 and libavformat to work. On the other hand, it is limited to ASS (Advanced
3055 Substation Alpha) subtitles files.
3057 This filter accepts the following option in addition to the common options from
3058 the @ref{subtitles} filter:
3062 Set the shaping engine
3064 Available values are:
3067 The default libass shaping engine, which is the best available.
3069 Fast, font-agnostic shaper that can do only substitutions
3071 Slower shaper using OpenType for substitutions and positioning
3074 The default is @code{auto}.
3078 Apply an Adaptive Temporal Averaging Denoiser to the video input.
3080 The filter accepts the following options:
3084 Set threshold A for 1st plane. Default is 0.02.
3085 Valid range is 0 to 0.3.
3088 Set threshold B for 1st plane. Default is 0.04.
3089 Valid range is 0 to 5.
3092 Set threshold A for 2nd plane. Default is 0.02.
3093 Valid range is 0 to 0.3.
3096 Set threshold B for 2nd plane. Default is 0.04.
3097 Valid range is 0 to 5.
3100 Set threshold A for 3rd plane. Default is 0.02.
3101 Valid range is 0 to 0.3.
3104 Set threshold B for 3rd plane. Default is 0.04.
3105 Valid range is 0 to 5.
3107 Threshold A is designed to react on abrupt changes in the input signal and
3108 threshold B is designed to react on continuous changes in the input signal.
3111 Set number of frames filter will use for averaging. Default is 33. Must be odd
3112 number in range [5, 129].
3117 Compute the bounding box for the non-black pixels in the input frame
3120 This filter computes the bounding box containing all the pixels with a
3121 luminance value greater than the minimum allowed value.
3122 The parameters describing the bounding box are printed on the filter
3125 The filter accepts the following option:
3129 Set the minimal luminance value. Default is @code{16}.
3132 @section blackdetect
3134 Detect video intervals that are (almost) completely black. Can be
3135 useful to detect chapter transitions, commercials, or invalid
3136 recordings. Output lines contains the time for the start, end and
3137 duration of the detected black interval expressed in seconds.
3139 In order to display the output lines, you need to set the loglevel at
3140 least to the AV_LOG_INFO value.
3142 The filter accepts the following options:
3145 @item black_min_duration, d
3146 Set the minimum detected black duration expressed in seconds. It must
3147 be a non-negative floating point number.
3149 Default value is 2.0.
3151 @item picture_black_ratio_th, pic_th
3152 Set the threshold for considering a picture "black".
3153 Express the minimum value for the ratio:
3155 @var{nb_black_pixels} / @var{nb_pixels}
3158 for which a picture is considered black.
3159 Default value is 0.98.
3161 @item pixel_black_th, pix_th
3162 Set the threshold for considering a pixel "black".
3164 The threshold expresses the maximum pixel luminance value for which a
3165 pixel is considered "black". The provided value is scaled according to
3166 the following equation:
3168 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
3171 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
3172 the input video format, the range is [0-255] for YUV full-range
3173 formats and [16-235] for YUV non full-range formats.
3175 Default value is 0.10.
3178 The following example sets the maximum pixel threshold to the minimum
3179 value, and detects only black intervals of 2 or more seconds:
3181 blackdetect=d=2:pix_th=0.00
3186 Detect frames that are (almost) completely black. Can be useful to
3187 detect chapter transitions or commercials. Output lines consist of
3188 the frame number of the detected frame, the percentage of blackness,
3189 the position in the file if known or -1 and the timestamp in seconds.
3191 In order to display the output lines, you need to set the loglevel at
3192 least to the AV_LOG_INFO value.
3194 It accepts the following parameters:
3199 The percentage of the pixels that have to be below the threshold; it defaults to
3202 @item threshold, thresh
3203 The threshold below which a pixel value is considered black; it defaults to
3208 @section blend, tblend
3210 Blend two video frames into each other.
3212 The @code{blend} filter takes two input streams and outputs one
3213 stream, the first input is the "top" layer and second input is
3214 "bottom" layer. Output terminates when shortest input terminates.
3216 The @code{tblend} (time blend) filter takes two consecutive frames
3217 from one single stream, and outputs the result obtained by blending
3218 the new frame on top of the old frame.
3220 A description of the accepted options follows.
3228 Set blend mode for specific pixel component or all pixel components in case
3229 of @var{all_mode}. Default value is @code{normal}.
3231 Available values for component modes are:
3268 Set blend opacity for specific pixel component or all pixel components in case
3269 of @var{all_opacity}. Only used in combination with pixel component blend modes.
3276 Set blend expression for specific pixel component or all pixel components in case
3277 of @var{all_expr}. Note that related mode options will be ignored if those are set.
3279 The expressions can use the following variables:
3283 The sequential number of the filtered frame, starting from @code{0}.
3287 the coordinates of the current sample
3291 the width and height of currently filtered plane
3295 Width and height scale depending on the currently filtered plane. It is the
3296 ratio between the corresponding luma plane number of pixels and the current
3297 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
3298 @code{0.5,0.5} for chroma planes.
3301 Time of the current frame, expressed in seconds.
3304 Value of pixel component at current location for first video frame (top layer).
3307 Value of pixel component at current location for second video frame (bottom layer).
3311 Force termination when the shortest input terminates. Default is
3312 @code{0}. This option is only defined for the @code{blend} filter.
3315 Continue applying the last bottom frame after the end of the stream. A value of
3316 @code{0} disable the filter after the last frame of the bottom layer is reached.
3317 Default is @code{1}. This option is only defined for the @code{blend} filter.
3320 @subsection Examples
3324 Apply transition from bottom layer to top layer in first 10 seconds:
3326 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
3330 Apply 1x1 checkerboard effect:
3332 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
3336 Apply uncover left effect:
3338 blend=all_expr='if(gte(N*SW+X,W),A,B)'
3342 Apply uncover down effect:
3344 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
3348 Apply uncover up-left effect:
3350 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
3354 Display differences between the current and the previous frame:
3356 tblend=all_mode=difference128
3362 Apply a boxblur algorithm to the input video.
3364 It accepts the following parameters:
3368 @item luma_radius, lr
3369 @item luma_power, lp
3370 @item chroma_radius, cr
3371 @item chroma_power, cp
3372 @item alpha_radius, ar
3373 @item alpha_power, ap
3377 A description of the accepted options follows.
3380 @item luma_radius, lr
3381 @item chroma_radius, cr
3382 @item alpha_radius, ar
3383 Set an expression for the box radius in pixels used for blurring the
3384 corresponding input plane.
3386 The radius value must be a non-negative number, and must not be
3387 greater than the value of the expression @code{min(w,h)/2} for the
3388 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
3391 Default value for @option{luma_radius} is "2". If not specified,
3392 @option{chroma_radius} and @option{alpha_radius} default to the
3393 corresponding value set for @option{luma_radius}.
3395 The expressions can contain the following constants:
3399 The input width and height in pixels.
3403 The input chroma image width and height in pixels.
3407 The horizontal and vertical chroma subsample values. For example, for the
3408 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
3411 @item luma_power, lp
3412 @item chroma_power, cp
3413 @item alpha_power, ap
3414 Specify how many times the boxblur filter is applied to the
3415 corresponding plane.
3417 Default value for @option{luma_power} is 2. If not specified,
3418 @option{chroma_power} and @option{alpha_power} default to the
3419 corresponding value set for @option{luma_power}.
3421 A value of 0 will disable the effect.
3424 @subsection Examples
3428 Apply a boxblur filter with the luma, chroma, and alpha radii
3431 boxblur=luma_radius=2:luma_power=1
3436 Set the luma radius to 2, and alpha and chroma radius to 0:
3438 boxblur=2:1:cr=0:ar=0
3442 Set the luma and chroma radii to a fraction of the video dimension:
3444 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
3450 Visualize information exported by some codecs.
3452 Some codecs can export information through frames using side-data or other
3453 means. For example, some MPEG based codecs export motion vectors through the
3454 @var{export_mvs} flag in the codec @option{flags2} option.
3456 The filter accepts the following option:
3460 Set motion vectors to visualize.
3462 Available flags for @var{mv} are:
3466 forward predicted MVs of P-frames
3468 forward predicted MVs of B-frames
3470 backward predicted MVs of B-frames
3474 @subsection Examples
3478 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
3480 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
3484 @section colorbalance
3485 Modify intensity of primary colors (red, green and blue) of input frames.
3487 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
3488 regions for the red-cyan, green-magenta or blue-yellow balance.
3490 A positive adjustment value shifts the balance towards the primary color, a negative
3491 value towards the complementary color.
3493 The filter accepts the following options:
3499 Adjust red, green and blue shadows (darkest pixels).
3504 Adjust red, green and blue midtones (medium pixels).
3509 Adjust red, green and blue highlights (brightest pixels).
3511 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
3514 @subsection Examples
3518 Add red color cast to shadows:
3525 RGB colorspace color keying.
3527 The filter accepts the following options:
3531 The color which will be replaced with transparency.
3534 Similarity percentage with the key color.
3536 0.01 matches only the exact key color, while 1.0 matches everything.
3541 0.0 makes pixels either fully transparent, or not transparent at all.
3543 Higher values result in semi-transparent pixels, with a higher transparency
3544 the more similar the pixels color is to the key color.
3547 @subsection Examples
3551 Make every green pixel in the input image transparent:
3553 ffmpeg -i input.png -vf colorkey=green out.png
3557 Overlay a greenscreen-video on top of a static background image.
3559 ffmpeg -i background.png -i video.mp4 -filter_complex "[1:v]colorkey=0x3BBD1E:0.3:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.flv
3563 @section colorlevels
3565 Adjust video input frames using levels.
3567 The filter accepts the following options:
3574 Adjust red, green, blue and alpha input black point.
3575 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
3581 Adjust red, green, blue and alpha input white point.
3582 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
3584 Input levels are used to lighten highlights (bright tones), darken shadows
3585 (dark tones), change the balance of bright and dark tones.
3591 Adjust red, green, blue and alpha output black point.
3592 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
3598 Adjust red, green, blue and alpha output white point.
3599 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
3601 Output levels allows manual selection of a constrained output level range.
3604 @subsection Examples
3608 Make video output darker:
3610 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
3616 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
3620 Make video output lighter:
3622 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
3626 Increase brightness:
3628 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
3632 @section colorchannelmixer
3634 Adjust video input frames by re-mixing color channels.
3636 This filter modifies a color channel by adding the values associated to
3637 the other channels of the same pixels. For example if the value to
3638 modify is red, the output value will be:
3640 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
3643 The filter accepts the following options:
3650 Adjust contribution of input red, green, blue and alpha channels for output red channel.
3651 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
3657 Adjust contribution of input red, green, blue and alpha channels for output green channel.
3658 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
3664 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
3665 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
3671 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
3672 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
3674 Allowed ranges for options are @code{[-2.0, 2.0]}.
3677 @subsection Examples
3681 Convert source to grayscale:
3683 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
3686 Simulate sepia tones:
3688 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
3692 @section colormatrix
3694 Convert color matrix.
3696 The filter accepts the following options:
3701 Specify the source and destination color matrix. Both values must be
3704 The accepted values are:
3720 For example to convert from BT.601 to SMPTE-240M, use the command:
3722 colormatrix=bt601:smpte240m
3727 Copy the input source unchanged to the output. This is mainly useful for
3732 Crop the input video to given dimensions.
3734 It accepts the following parameters:
3738 The width of the output video. It defaults to @code{iw}.
3739 This expression is evaluated only once during the filter
3740 configuration, or when the @samp{w} or @samp{out_w} command is sent.
3743 The height of the output video. It defaults to @code{ih}.
3744 This expression is evaluated only once during the filter
3745 configuration, or when the @samp{h} or @samp{out_h} command is sent.
3748 The horizontal position, in the input video, of the left edge of the output
3749 video. It defaults to @code{(in_w-out_w)/2}.
3750 This expression is evaluated per-frame.
3753 The vertical position, in the input video, of the top edge of the output video.
3754 It defaults to @code{(in_h-out_h)/2}.
3755 This expression is evaluated per-frame.
3758 If set to 1 will force the output display aspect ratio
3759 to be the same of the input, by changing the output sample aspect
3760 ratio. It defaults to 0.
3763 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
3764 expressions containing the following constants:
3769 The computed values for @var{x} and @var{y}. They are evaluated for
3774 The input width and height.
3778 These are the same as @var{in_w} and @var{in_h}.
3782 The output (cropped) width and height.
3786 These are the same as @var{out_w} and @var{out_h}.
3789 same as @var{iw} / @var{ih}
3792 input sample aspect ratio
3795 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
3799 horizontal and vertical chroma subsample values. For example for the
3800 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3803 The number of the input frame, starting from 0.
3806 the position in the file of the input frame, NAN if unknown
3809 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
3813 The expression for @var{out_w} may depend on the value of @var{out_h},
3814 and the expression for @var{out_h} may depend on @var{out_w}, but they
3815 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
3816 evaluated after @var{out_w} and @var{out_h}.
3818 The @var{x} and @var{y} parameters specify the expressions for the
3819 position of the top-left corner of the output (non-cropped) area. They
3820 are evaluated for each frame. If the evaluated value is not valid, it
3821 is approximated to the nearest valid value.
3823 The expression for @var{x} may depend on @var{y}, and the expression
3824 for @var{y} may depend on @var{x}.
3826 @subsection Examples
3830 Crop area with size 100x100 at position (12,34).
3835 Using named options, the example above becomes:
3837 crop=w=100:h=100:x=12:y=34
3841 Crop the central input area with size 100x100:
3847 Crop the central input area with size 2/3 of the input video:
3849 crop=2/3*in_w:2/3*in_h
3853 Crop the input video central square:
3860 Delimit the rectangle with the top-left corner placed at position
3861 100:100 and the right-bottom corner corresponding to the right-bottom
3862 corner of the input image.
3864 crop=in_w-100:in_h-100:100:100
3868 Crop 10 pixels from the left and right borders, and 20 pixels from
3869 the top and bottom borders
3871 crop=in_w-2*10:in_h-2*20
3875 Keep only the bottom right quarter of the input image:
3877 crop=in_w/2:in_h/2:in_w/2:in_h/2
3881 Crop height for getting Greek harmony:
3883 crop=in_w:1/PHI*in_w
3887 Apply trembling effect:
3889 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)
3893 Apply erratic camera effect depending on timestamp:
3895 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)"
3899 Set x depending on the value of y:
3901 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3905 @subsection Commands
3907 This filter supports the following commands:
3913 Set width/height of the output video and the horizontal/vertical position
3915 The command accepts the same syntax of the corresponding option.
3917 If the specified expression is not valid, it is kept at its current
3923 Auto-detect the crop size.
3925 It calculates the necessary cropping parameters and prints the
3926 recommended parameters via the logging system. The detected dimensions
3927 correspond to the non-black area of the input video.
3929 It accepts the following parameters:
3934 Set higher black value threshold, which can be optionally specified
3935 from nothing (0) to everything (255 for 8bit based formats). An intensity
3936 value greater to the set value is considered non-black. It defaults to 24.
3937 You can also specify a value between 0.0 and 1.0 which will be scaled depending
3938 on the bitdepth of the pixel format.
3941 The value which the width/height should be divisible by. It defaults to
3942 16. The offset is automatically adjusted to center the video. Use 2 to
3943 get only even dimensions (needed for 4:2:2 video). 16 is best when
3944 encoding to most video codecs.
3946 @item reset_count, reset
3947 Set the counter that determines after how many frames cropdetect will
3948 reset the previously detected largest video area and start over to
3949 detect the current optimal crop area. Default value is 0.
3951 This can be useful when channel logos distort the video area. 0
3952 indicates 'never reset', and returns the largest area encountered during
3959 Apply color adjustments using curves.
3961 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3962 component (red, green and blue) has its values defined by @var{N} key points
3963 tied from each other using a smooth curve. The x-axis represents the pixel
3964 values from the input frame, and the y-axis the new pixel values to be set for
3967 By default, a component curve is defined by the two points @var{(0;0)} and
3968 @var{(1;1)}. This creates a straight line where each original pixel value is
3969 "adjusted" to its own value, which means no change to the image.
3971 The filter allows you to redefine these two points and add some more. A new
3972 curve (using a natural cubic spline interpolation) will be define to pass
3973 smoothly through all these new coordinates. The new defined points needs to be
3974 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3975 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3976 the vector spaces, the values will be clipped accordingly.
3978 If there is no key point defined in @code{x=0}, the filter will automatically
3979 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3980 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3982 The filter accepts the following options:
3986 Select one of the available color presets. This option can be used in addition
3987 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3988 options takes priority on the preset values.
3989 Available presets are:
3992 @item color_negative
3995 @item increase_contrast
3997 @item linear_contrast
3998 @item medium_contrast
4000 @item strong_contrast
4003 Default is @code{none}.
4005 Set the master key points. These points will define a second pass mapping. It
4006 is sometimes called a "luminance" or "value" mapping. It can be used with
4007 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
4008 post-processing LUT.
4010 Set the key points for the red component.
4012 Set the key points for the green component.
4014 Set the key points for the blue component.
4016 Set the key points for all components (not including master).
4017 Can be used in addition to the other key points component
4018 options. In this case, the unset component(s) will fallback on this
4019 @option{all} setting.
4021 Specify a Photoshop curves file (@code{.acv}) to import the settings from.
4024 To avoid some filtergraph syntax conflicts, each key points list need to be
4025 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
4027 @subsection Examples
4031 Increase slightly the middle level of blue:
4033 curves=blue='0.5/0.58'
4039 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
4041 Here we obtain the following coordinates for each components:
4044 @code{(0;0.11) (0.42;0.51) (1;0.95)}
4046 @code{(0;0) (0.50;0.48) (1;1)}
4048 @code{(0;0.22) (0.49;0.44) (1;0.80)}
4052 The previous example can also be achieved with the associated built-in preset:
4054 curves=preset=vintage
4064 Use a Photoshop preset and redefine the points of the green component:
4066 curves=psfile='MyCurvesPresets/purple.acv':green='0.45/0.53'
4072 Denoise frames using 2D DCT (frequency domain filtering).
4074 This filter is not designed for real time.
4076 The filter accepts the following options:
4080 Set the noise sigma constant.
4082 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
4083 coefficient (absolute value) below this threshold with be dropped.
4085 If you need a more advanced filtering, see @option{expr}.
4087 Default is @code{0}.
4090 Set number overlapping pixels for each block. Since the filter can be slow, you
4091 may want to reduce this value, at the cost of a less effective filter and the
4092 risk of various artefacts.
4094 If the overlapping value doesn't permit processing the whole input width or
4095 height, a warning will be displayed and according borders won't be denoised.
4097 Default value is @var{blocksize}-1, which is the best possible setting.
4100 Set the coefficient factor expression.
4102 For each coefficient of a DCT block, this expression will be evaluated as a
4103 multiplier value for the coefficient.
4105 If this is option is set, the @option{sigma} option will be ignored.
4107 The absolute value of the coefficient can be accessed through the @var{c}
4111 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
4112 @var{blocksize}, which is the width and height of the processed blocks.
4114 The default value is @var{3} (8x8) and can be raised to @var{4} for a
4115 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
4116 on the speed processing. Also, a larger block size does not necessarily means a
4120 @subsection Examples
4122 Apply a denoise with a @option{sigma} of @code{4.5}:
4127 The same operation can be achieved using the expression system:
4129 dctdnoiz=e='gte(c, 4.5*3)'
4132 Violent denoise using a block size of @code{16x16}:
4139 Remove banding artifacts from input video.
4140 It works by replacing banded pixels with average value of referenced pixels.
4142 The filter accepts the following options:
4149 Set banding detection threshold for each plane. Default is 0.02.
4150 Valid range is 0.00003 to 0.5.
4151 If difference between current pixel and reference pixel is less than threshold,
4152 it will be considered as banded.
4155 Banding detection range in pixels. Default is 16. If positive, random number
4156 in range 0 to set value will be used. If negative, exact absolute value
4158 The range defines square of four pixels around current pixel.
4161 Set direction in radians from which four pixel will be compared. If positive,
4162 random direction from 0 to set direction will be picked. If negative, exact of
4163 absolute value will be picked. For example direction 0, -PI or -2*PI radians
4164 will pick only pixels on same row and -PI/2 will pick only pixels on same
4168 If enabled, current pixel is compared with average value of all four
4169 surrounding pixels. The default is enabled. If disabled current pixel is
4170 compared with all four surrounding pixels. The pixel is considered banded
4171 if only all four differences with surrounding pixels are less than threshold.
4177 Drop duplicated frames at regular intervals.
4179 The filter accepts the following options:
4183 Set the number of frames from which one will be dropped. Setting this to
4184 @var{N} means one frame in every batch of @var{N} frames will be dropped.
4185 Default is @code{5}.
4188 Set the threshold for duplicate detection. If the difference metric for a frame
4189 is less than or equal to this value, then it is declared as duplicate. Default
4193 Set scene change threshold. Default is @code{15}.
4197 Set the size of the x and y-axis blocks used during metric calculations.
4198 Larger blocks give better noise suppression, but also give worse detection of
4199 small movements. Must be a power of two. Default is @code{32}.
4202 Mark main input as a pre-processed input and activate clean source input
4203 stream. This allows the input to be pre-processed with various filters to help
4204 the metrics calculation while keeping the frame selection lossless. When set to
4205 @code{1}, the first stream is for the pre-processed input, and the second
4206 stream is the clean source from where the kept frames are chosen. Default is
4210 Set whether or not chroma is considered in the metric calculations. Default is
4216 Apply deflate effect to the video.
4218 This filter replaces the pixel by the local(3x3) average by taking into account
4219 only values lower than the pixel.
4221 It accepts the following options:
4228 Allows to limit the maximum change for each plane, default is 65535.
4229 If 0, plane will remain unchanged.
4234 Remove judder produced by partially interlaced telecined content.
4236 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
4237 source was partially telecined content then the output of @code{pullup,dejudder}
4238 will have a variable frame rate. May change the recorded frame rate of the
4239 container. Aside from that change, this filter will not affect constant frame
4242 The option available in this filter is:
4246 Specify the length of the window over which the judder repeats.
4248 Accepts any integer greater than 1. Useful values are:
4252 If the original was telecined from 24 to 30 fps (Film to NTSC).
4255 If the original was telecined from 25 to 30 fps (PAL to NTSC).
4258 If a mixture of the two.
4261 The default is @samp{4}.
4266 Suppress a TV station logo by a simple interpolation of the surrounding
4267 pixels. Just set a rectangle covering the logo and watch it disappear
4268 (and sometimes something even uglier appear - your mileage may vary).
4270 It accepts the following parameters:
4275 Specify the top left corner coordinates of the logo. They must be
4280 Specify the width and height of the logo to clear. They must be
4284 Specify the thickness of the fuzzy edge of the rectangle (added to
4285 @var{w} and @var{h}). The default value is 4.
4288 When set to 1, a green rectangle is drawn on the screen to simplify
4289 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
4290 The default value is 0.
4292 The rectangle is drawn on the outermost pixels which will be (partly)
4293 replaced with interpolated values. The values of the next pixels
4294 immediately outside this rectangle in each direction will be used to
4295 compute the interpolated pixel values inside the rectangle.
4299 @subsection Examples
4303 Set a rectangle covering the area with top left corner coordinates 0,0
4304 and size 100x77, and a band of size 10:
4306 delogo=x=0:y=0:w=100:h=77:band=10
4313 Attempt to fix small changes in horizontal and/or vertical shift. This
4314 filter helps remove camera shake from hand-holding a camera, bumping a
4315 tripod, moving on a vehicle, etc.
4317 The filter accepts the following options:
4325 Specify a rectangular area where to limit the search for motion
4327 If desired the search for motion vectors can be limited to a
4328 rectangular area of the frame defined by its top left corner, width
4329 and height. These parameters have the same meaning as the drawbox
4330 filter which can be used to visualise the position of the bounding
4333 This is useful when simultaneous movement of subjects within the frame
4334 might be confused for camera motion by the motion vector search.
4336 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
4337 then the full frame is used. This allows later options to be set
4338 without specifying the bounding box for the motion vector search.
4340 Default - search the whole frame.
4344 Specify the maximum extent of movement in x and y directions in the
4345 range 0-64 pixels. Default 16.
4348 Specify how to generate pixels to fill blanks at the edge of the
4349 frame. Available values are:
4352 Fill zeroes at blank locations
4354 Original image at blank locations
4356 Extruded edge value at blank locations
4358 Mirrored edge at blank locations
4360 Default value is @samp{mirror}.
4363 Specify the blocksize to use for motion search. Range 4-128 pixels,
4367 Specify the contrast threshold for blocks. Only blocks with more than
4368 the specified contrast (difference between darkest and lightest
4369 pixels) will be considered. Range 1-255, default 125.
4372 Specify the search strategy. Available values are:
4375 Set exhaustive search
4377 Set less exhaustive search.
4379 Default value is @samp{exhaustive}.
4382 If set then a detailed log of the motion search is written to the
4386 If set to 1, specify using OpenCL capabilities, only available if
4387 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
4393 Apply an exact inverse of the telecine operation. It requires a predefined
4394 pattern specified using the pattern option which must be the same as that passed
4395 to the telecine filter.
4397 This filter accepts the following options:
4406 The default value is @code{top}.
4410 A string of numbers representing the pulldown pattern you wish to apply.
4411 The default value is @code{23}.
4414 A number representing position of the first frame with respect to the telecine
4415 pattern. This is to be used if the stream is cut. The default value is @code{0}.
4420 Apply dilation effect to the video.
4422 This filter replaces the pixel by the local(3x3) maximum.
4424 It accepts the following options:
4431 Allows to limit the maximum change for each plane, default is 65535.
4432 If 0, plane will remain unchanged.
4435 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
4438 Flags to local 3x3 coordinates maps like this:
4447 Draw a colored box on the input image.
4449 It accepts the following parameters:
4454 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
4458 The expressions which specify the width and height of the box; if 0 they are interpreted as
4459 the input width and height. It defaults to 0.
4462 Specify the color of the box to write. For the general syntax of this option,
4463 check the "Color" section in the ffmpeg-utils manual. If the special
4464 value @code{invert} is used, the box edge color is the same as the
4465 video with inverted luma.
4468 The expression which sets the thickness of the box edge. Default value is @code{3}.
4470 See below for the list of accepted constants.
4473 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
4474 following constants:
4478 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
4482 horizontal and vertical chroma subsample values. For example for the
4483 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4487 The input width and height.
4490 The input sample aspect ratio.
4494 The x and y offset coordinates where the box is drawn.
4498 The width and height of the drawn box.
4501 The thickness of the drawn box.
4503 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
4504 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
4508 @subsection Examples
4512 Draw a black box around the edge of the input image:
4518 Draw a box with color red and an opacity of 50%:
4520 drawbox=10:20:200:60:red@@0.5
4523 The previous example can be specified as:
4525 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
4529 Fill the box with pink color:
4531 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
4535 Draw a 2-pixel red 2.40:1 mask:
4537 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
4541 @section drawgraph, adrawgraph
4543 Draw a graph using input video or audio metadata.
4545 It accepts the following parameters:
4549 Set 1st frame metadata key from which metadata values will be used to draw a graph.
4552 Set 1st foreground color expression.
4555 Set 2nd frame metadata key from which metadata values will be used to draw a graph.
4558 Set 2nd foreground color expression.
4561 Set 3rd frame metadata key from which metadata values will be used to draw a graph.
4564 Set 3rd foreground color expression.
4567 Set 4th frame metadata key from which metadata values will be used to draw a graph.
4570 Set 4th foreground color expression.
4573 Set minimal value of metadata value.
4576 Set maximal value of metadata value.
4579 Set graph background color. Default is white.
4584 Available values for mode is:
4591 Default is @code{line}.
4596 Available values for slide is:
4599 Draw new frame when right border is reached.
4602 Replace old columns with new ones.
4605 Scroll from right to left.
4608 Scroll from left to right.
4611 Default is @code{frame}.
4614 Set size of graph video. For the syntax of this option, check the
4615 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
4616 The default value is @code{900x256}.
4618 The foreground color expressions can use the following variables:
4621 Minimal value of metadata value.
4624 Maximal value of metadata value.
4627 Current metadata key value.
4630 The color is defined as 0xAABBGGRR.
4633 Example using metadata from @ref{signalstats} filter:
4635 signalstats,drawgraph=lavfi.signalstats.YAVG:min=0:max=255
4638 Example using metadata from @ref{ebur128} filter:
4640 ebur128=metadata=1,adrawgraph=lavfi.r128.M:min=-120:max=5
4645 Draw a grid on the input image.
4647 It accepts the following parameters:
4652 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
4656 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
4657 input width and height, respectively, minus @code{thickness}, so image gets
4658 framed. Default to 0.
4661 Specify the color of the grid. For the general syntax of this option,
4662 check the "Color" section in the ffmpeg-utils manual. If the special
4663 value @code{invert} is used, the grid color is the same as the
4664 video with inverted luma.
4667 The expression which sets the thickness of the grid line. Default value is @code{1}.
4669 See below for the list of accepted constants.
4672 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
4673 following constants:
4677 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
4681 horizontal and vertical chroma subsample values. For example for the
4682 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4686 The input grid cell width and height.
4689 The input sample aspect ratio.
4693 The x and y coordinates of some point of grid intersection (meant to configure offset).
4697 The width and height of the drawn cell.
4700 The thickness of the drawn cell.
4702 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
4703 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
4707 @subsection Examples
4711 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
4713 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
4717 Draw a white 3x3 grid with an opacity of 50%:
4719 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
4726 Draw a text string or text from a specified file on top of a video, using the
4727 libfreetype library.
4729 To enable compilation of this filter, you need to configure FFmpeg with
4730 @code{--enable-libfreetype}.
4731 To enable default font fallback and the @var{font} option you need to
4732 configure FFmpeg with @code{--enable-libfontconfig}.
4733 To enable the @var{text_shaping} option, you need to configure FFmpeg with
4734 @code{--enable-libfribidi}.
4738 It accepts the following parameters:
4743 Used to draw a box around text using the background color.
4744 The value must be either 1 (enable) or 0 (disable).
4745 The default value of @var{box} is 0.
4748 Set the width of the border to be drawn around the box using @var{boxcolor}.
4749 The default value of @var{boxborderw} is 0.
4752 The color to be used for drawing box around text. For the syntax of this
4753 option, check the "Color" section in the ffmpeg-utils manual.
4755 The default value of @var{boxcolor} is "white".
4758 Set the width of the border to be drawn around the text using @var{bordercolor}.
4759 The default value of @var{borderw} is 0.
4762 Set the color to be used for drawing border around text. For the syntax of this
4763 option, check the "Color" section in the ffmpeg-utils manual.
4765 The default value of @var{bordercolor} is "black".
4768 Select how the @var{text} is expanded. Can be either @code{none},
4769 @code{strftime} (deprecated) or
4770 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
4774 If true, check and fix text coords to avoid clipping.
4777 The color to be used for drawing fonts. For the syntax of this option, check
4778 the "Color" section in the ffmpeg-utils manual.
4780 The default value of @var{fontcolor} is "black".
4782 @item fontcolor_expr
4783 String which is expanded the same way as @var{text} to obtain dynamic
4784 @var{fontcolor} value. By default this option has empty value and is not
4785 processed. When this option is set, it overrides @var{fontcolor} option.
4788 The font family to be used for drawing text. By default Sans.
4791 The font file to be used for drawing text. The path must be included.
4792 This parameter is mandatory if the fontconfig support is disabled.
4795 This option does not exist, please see the timeline system
4798 Draw the text applying alpha blending. The value can
4799 be either a number between 0.0 and 1.0
4800 The expression accepts the same variables @var{x, y} do.
4801 The default value is 1.
4802 Please see fontcolor_expr
4805 The font size to be used for drawing text.
4806 The default value of @var{fontsize} is 16.
4809 If set to 1, attempt to shape the text (for example, reverse the order of
4810 right-to-left text and join Arabic characters) before drawing it.
4811 Otherwise, just draw the text exactly as given.
4812 By default 1 (if supported).
4815 The flags to be used for loading the fonts.
4817 The flags map the corresponding flags supported by libfreetype, and are
4818 a combination of the following values:
4825 @item vertical_layout
4826 @item force_autohint
4829 @item ignore_global_advance_width
4831 @item ignore_transform
4837 Default value is "default".
4839 For more information consult the documentation for the FT_LOAD_*
4843 The color to be used for drawing a shadow behind the drawn text. For the
4844 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
4846 The default value of @var{shadowcolor} is "black".
4850 The x and y offsets for the text shadow position with respect to the
4851 position of the text. They can be either positive or negative
4852 values. The default value for both is "0".
4855 The starting frame number for the n/frame_num variable. The default value
4859 The size in number of spaces to use for rendering the tab.
4863 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
4864 format. It can be used with or without text parameter. @var{timecode_rate}
4865 option must be specified.
4867 @item timecode_rate, rate, r
4868 Set the timecode frame rate (timecode only).
4871 The text string to be drawn. The text must be a sequence of UTF-8
4873 This parameter is mandatory if no file is specified with the parameter
4877 A text file containing text to be drawn. The text must be a sequence
4878 of UTF-8 encoded characters.
4880 This parameter is mandatory if no text string is specified with the
4881 parameter @var{text}.
4883 If both @var{text} and @var{textfile} are specified, an error is thrown.
4886 If set to 1, the @var{textfile} will be reloaded before each frame.
4887 Be sure to update it atomically, or it may be read partially, or even fail.
4891 The expressions which specify the offsets where text will be drawn
4892 within the video frame. They are relative to the top/left border of the
4895 The default value of @var{x} and @var{y} is "0".
4897 See below for the list of accepted constants and functions.
4900 The parameters for @var{x} and @var{y} are expressions containing the
4901 following constants and functions:
4905 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
4909 horizontal and vertical chroma subsample values. For example for the
4910 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4913 the height of each text line
4921 @item max_glyph_a, ascent
4922 the maximum distance from the baseline to the highest/upper grid
4923 coordinate used to place a glyph outline point, for all the rendered
4925 It is a positive value, due to the grid's orientation with the Y axis
4928 @item max_glyph_d, descent
4929 the maximum distance from the baseline to the lowest grid coordinate
4930 used to place a glyph outline point, for all the rendered glyphs.
4931 This is a negative value, due to the grid's orientation, with the Y axis
4935 maximum glyph height, that is the maximum height for all the glyphs
4936 contained in the rendered text, it is equivalent to @var{ascent} -
4940 maximum glyph width, that is the maximum width for all the glyphs
4941 contained in the rendered text
4944 the number of input frame, starting from 0
4946 @item rand(min, max)
4947 return a random number included between @var{min} and @var{max}
4950 The input sample aspect ratio.
4953 timestamp expressed in seconds, NAN if the input timestamp is unknown
4956 the height of the rendered text
4959 the width of the rendered text
4963 the x and y offset coordinates where the text is drawn.
4965 These parameters allow the @var{x} and @var{y} expressions to refer
4966 each other, so you can for example specify @code{y=x/dar}.
4969 @anchor{drawtext_expansion}
4970 @subsection Text expansion
4972 If @option{expansion} is set to @code{strftime},
4973 the filter recognizes strftime() sequences in the provided text and
4974 expands them accordingly. Check the documentation of strftime(). This
4975 feature is deprecated.
4977 If @option{expansion} is set to @code{none}, the text is printed verbatim.
4979 If @option{expansion} is set to @code{normal} (which is the default),
4980 the following expansion mechanism is used.
4982 The backslash character @samp{\}, followed by any character, always expands to
4983 the second character.
4985 Sequence of the form @code{%@{...@}} are expanded. The text between the
4986 braces is a function name, possibly followed by arguments separated by ':'.
4987 If the arguments contain special characters or delimiters (':' or '@}'),
4988 they should be escaped.
4990 Note that they probably must also be escaped as the value for the
4991 @option{text} option in the filter argument string and as the filter
4992 argument in the filtergraph description, and possibly also for the shell,
4993 that makes up to four levels of escaping; using a text file avoids these
4996 The following functions are available:
5001 The expression evaluation result.
5003 It must take one argument specifying the expression to be evaluated,
5004 which accepts the same constants and functions as the @var{x} and
5005 @var{y} values. Note that not all constants should be used, for
5006 example the text size is not known when evaluating the expression, so
5007 the constants @var{text_w} and @var{text_h} will have an undefined
5010 @item expr_int_format, eif
5011 Evaluate the expression's value and output as formatted integer.
5013 The first argument is the expression to be evaluated, just as for the @var{expr} function.
5014 The second argument specifies the output format. Allowed values are @samp{x},
5015 @samp{X}, @samp{d} and @samp{u}. They are treated exactly as in the
5016 @code{printf} function.
5017 The third parameter is optional and sets the number of positions taken by the output.
5018 It can be used to add padding with zeros from the left.
5021 The time at which the filter is running, expressed in UTC.
5022 It can accept an argument: a strftime() format string.
5025 The time at which the filter is running, expressed in the local time zone.
5026 It can accept an argument: a strftime() format string.
5029 Frame metadata. It must take one argument specifying metadata key.
5032 The frame number, starting from 0.
5035 A 1 character description of the current picture type.
5038 The timestamp of the current frame.
5039 It can take up to two arguments.
5041 The first argument is the format of the timestamp; it defaults to @code{flt}
5042 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
5043 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
5045 The second argument is an offset added to the timestamp.
5049 @subsection Examples
5053 Draw "Test Text" with font FreeSerif, using the default values for the
5054 optional parameters.
5057 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
5061 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
5062 and y=50 (counting from the top-left corner of the screen), text is
5063 yellow with a red box around it. Both the text and the box have an
5067 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
5068 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
5071 Note that the double quotes are not necessary if spaces are not used
5072 within the parameter list.
5075 Show the text at the center of the video frame:
5077 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
5081 Show a text line sliding from right to left in the last row of the video
5082 frame. The file @file{LONG_LINE} is assumed to contain a single line
5085 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
5089 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
5091 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
5095 Draw a single green letter "g", at the center of the input video.
5096 The glyph baseline is placed at half screen height.
5098 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
5102 Show text for 1 second every 3 seconds:
5104 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
5108 Use fontconfig to set the font. Note that the colons need to be escaped.
5110 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
5114 Print the date of a real-time encoding (see strftime(3)):
5116 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
5120 Show text fading in and out (appearing/disappearing):
5123 DS=1.0 # display start
5124 DE=10.0 # display end
5125 FID=1.5 # fade in duration
5126 FOD=5 # fade out duration
5127 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 @}"
5132 For more information about libfreetype, check:
5133 @url{http://www.freetype.org/}.
5135 For more information about fontconfig, check:
5136 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
5138 For more information about libfribidi, check:
5139 @url{http://fribidi.org/}.
5143 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
5145 The filter accepts the following options:
5150 Set low and high threshold values used by the Canny thresholding
5153 The high threshold selects the "strong" edge pixels, which are then
5154 connected through 8-connectivity with the "weak" edge pixels selected
5155 by the low threshold.
5157 @var{low} and @var{high} threshold values must be chosen in the range
5158 [0,1], and @var{low} should be lesser or equal to @var{high}.
5160 Default value for @var{low} is @code{20/255}, and default value for @var{high}
5164 Define the drawing mode.
5168 Draw white/gray wires on black background.
5171 Mix the colors to create a paint/cartoon effect.
5174 Default value is @var{wires}.
5177 @subsection Examples
5181 Standard edge detection with custom values for the hysteresis thresholding:
5183 edgedetect=low=0.1:high=0.4
5187 Painting effect without thresholding:
5189 edgedetect=mode=colormix:high=0
5194 Set brightness, contrast, saturation and approximate gamma adjustment.
5196 The filter accepts the following options:
5200 Set the contrast expression. The value must be a float value in range
5201 @code{-2.0} to @code{2.0}. The default value is "0".
5204 Set the brightness expression. The value must be a float value in
5205 range @code{-1.0} to @code{1.0}. The default value is "0".
5208 Set the saturation expression. The value must be a float in
5209 range @code{0.0} to @code{3.0}. The default value is "1".
5212 Set the gamma expression. The value must be a float in range
5213 @code{0.1} to @code{10.0}. The default value is "1".
5216 Set the gamma expression for red. The value must be a float in
5217 range @code{0.1} to @code{10.0}. The default value is "1".
5220 Set the gamma expression for green. The value must be a float in range
5221 @code{0.1} to @code{10.0}. The default value is "1".
5224 Set the gamma expression for blue. The value must be a float in range
5225 @code{0.1} to @code{10.0}. The default value is "1".
5228 Set the gamma weight expression. It can be used to reduce the effect
5229 of a high gamma value on bright image areas, e.g. keep them from
5230 getting overamplified and just plain white. The value must be a float
5231 in range @code{0.0} to @code{1.0}. A value of @code{0.0} turns the
5232 gamma correction all the way down while @code{1.0} leaves it at its
5233 full strength. Default is "1".
5236 Set when the expressions for brightness, contrast, saturation and
5237 gamma expressions are evaluated.
5239 It accepts the following values:
5242 only evaluate expressions once during the filter initialization or
5243 when a command is processed
5246 evaluate expressions for each incoming frame
5249 Default value is @samp{init}.
5252 The expressions accept the following parameters:
5255 frame count of the input frame starting from 0
5258 byte position of the corresponding packet in the input file, NAN if
5262 frame rate of the input video, NAN if the input frame rate is unknown
5265 timestamp expressed in seconds, NAN if the input timestamp is unknown
5268 @subsection Commands
5269 The filter supports the following commands:
5273 Set the contrast expression.
5276 Set the brightness expression.
5279 Set the saturation expression.
5282 Set the gamma expression.
5285 Set the gamma_r expression.
5288 Set gamma_g expression.
5291 Set gamma_b expression.
5294 Set gamma_weight expression.
5296 The command accepts the same syntax of the corresponding option.
5298 If the specified expression is not valid, it is kept at its current
5305 Apply erosion effect to the video.
5307 This filter replaces the pixel by the local(3x3) minimum.
5309 It accepts the following options:
5316 Allows to limit the maximum change for each plane, default is 65535.
5317 If 0, plane will remain unchanged.
5320 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
5323 Flags to local 3x3 coordinates maps like this:
5330 @section extractplanes
5332 Extract color channel components from input video stream into
5333 separate grayscale video streams.
5335 The filter accepts the following option:
5339 Set plane(s) to extract.
5341 Available values for planes are:
5352 Choosing planes not available in the input will result in an error.
5353 That means you cannot select @code{r}, @code{g}, @code{b} planes
5354 with @code{y}, @code{u}, @code{v} planes at same time.
5357 @subsection Examples
5361 Extract luma, u and v color channel component from input video frame
5362 into 3 grayscale outputs:
5364 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
5370 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
5372 For each input image, the filter will compute the optimal mapping from
5373 the input to the output given the codebook length, that is the number
5374 of distinct output colors.
5376 This filter accepts the following options.
5379 @item codebook_length, l
5380 Set codebook length. The value must be a positive integer, and
5381 represents the number of distinct output colors. Default value is 256.
5384 Set the maximum number of iterations to apply for computing the optimal
5385 mapping. The higher the value the better the result and the higher the
5386 computation time. Default value is 1.
5389 Set a random seed, must be an integer included between 0 and
5390 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
5391 will try to use a good random seed on a best effort basis.
5394 Set pal8 output pixel format. This option does not work with codebook
5395 length greater than 256.
5400 Apply a fade-in/out effect to the input video.
5402 It accepts the following parameters:
5406 The effect type can be either "in" for a fade-in, or "out" for a fade-out
5408 Default is @code{in}.
5410 @item start_frame, s
5411 Specify the number of the frame to start applying the fade
5412 effect at. Default is 0.
5415 The number of frames that the fade effect lasts. At the end of the
5416 fade-in effect, the output video will have the same intensity as the input video.
5417 At the end of the fade-out transition, the output video will be filled with the
5418 selected @option{color}.
5422 If set to 1, fade only alpha channel, if one exists on the input.
5425 @item start_time, st
5426 Specify the timestamp (in seconds) of the frame to start to apply the fade
5427 effect. If both start_frame and start_time are specified, the fade will start at
5428 whichever comes last. Default is 0.
5431 The number of seconds for which the fade effect has to last. At the end of the
5432 fade-in effect the output video will have the same intensity as the input video,
5433 at the end of the fade-out transition the output video will be filled with the
5434 selected @option{color}.
5435 If both duration and nb_frames are specified, duration is used. Default is 0
5436 (nb_frames is used by default).
5439 Specify the color of the fade. Default is "black".
5442 @subsection Examples
5446 Fade in the first 30 frames of video:
5451 The command above is equivalent to:
5457 Fade out the last 45 frames of a 200-frame video:
5460 fade=type=out:start_frame=155:nb_frames=45
5464 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
5466 fade=in:0:25, fade=out:975:25
5470 Make the first 5 frames yellow, then fade in from frame 5-24:
5472 fade=in:5:20:color=yellow
5476 Fade in alpha over first 25 frames of video:
5478 fade=in:0:25:alpha=1
5482 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
5484 fade=t=in:st=5.5:d=0.5
5490 Apply arbitrary expressions to samples in frequency domain
5494 Adjust the dc value (gain) of the luma plane of the image. The filter
5495 accepts an integer value in range @code{0} to @code{1000}. The default
5496 value is set to @code{0}.
5499 Adjust the dc value (gain) of the 1st chroma plane of the image. The
5500 filter accepts an integer value in range @code{0} to @code{1000}. The
5501 default value is set to @code{0}.
5504 Adjust the dc value (gain) of the 2nd chroma plane of the image. The
5505 filter accepts an integer value in range @code{0} to @code{1000}. The
5506 default value is set to @code{0}.
5509 Set the frequency domain weight expression for the luma plane.
5512 Set the frequency domain weight expression for the 1st chroma plane.
5515 Set the frequency domain weight expression for the 2nd chroma plane.
5517 The filter accepts the following variables:
5520 The coordinates of the current sample.
5524 The width and height of the image.
5527 @subsection Examples
5533 fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
5539 fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
5545 fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
5552 Extract a single field from an interlaced image using stride
5553 arithmetic to avoid wasting CPU time. The output frames are marked as
5556 The filter accepts the following options:
5560 Specify whether to extract the top (if the value is @code{0} or
5561 @code{top}) or the bottom field (if the value is @code{1} or
5567 Field matching filter for inverse telecine. It is meant to reconstruct the
5568 progressive frames from a telecined stream. The filter does not drop duplicated
5569 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
5570 followed by a decimation filter such as @ref{decimate} in the filtergraph.
5572 The separation of the field matching and the decimation is notably motivated by
5573 the possibility of inserting a de-interlacing filter fallback between the two.
5574 If the source has mixed telecined and real interlaced content,
5575 @code{fieldmatch} will not be able to match fields for the interlaced parts.
5576 But these remaining combed frames will be marked as interlaced, and thus can be
5577 de-interlaced by a later filter such as @ref{yadif} before decimation.
5579 In addition to the various configuration options, @code{fieldmatch} can take an
5580 optional second stream, activated through the @option{ppsrc} option. If
5581 enabled, the frames reconstruction will be based on the fields and frames from
5582 this second stream. This allows the first input to be pre-processed in order to
5583 help the various algorithms of the filter, while keeping the output lossless
5584 (assuming the fields are matched properly). Typically, a field-aware denoiser,
5585 or brightness/contrast adjustments can help.
5587 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
5588 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
5589 which @code{fieldmatch} is based on. While the semantic and usage are very
5590 close, some behaviour and options names can differ.
5592 The @ref{decimate} filter currently only works for constant frame rate input.
5593 If your input has mixed telecined (30fps) and progressive content with a lower
5594 framerate like 24fps use the following filterchain to produce the necessary cfr
5595 stream: @code{dejudder,fps=30000/1001,fieldmatch,decimate}.
5597 The filter accepts the following options:
5601 Specify the assumed field order of the input stream. Available values are:
5605 Auto detect parity (use FFmpeg's internal parity value).
5607 Assume bottom field first.
5609 Assume top field first.
5612 Note that it is sometimes recommended not to trust the parity announced by the
5615 Default value is @var{auto}.
5618 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
5619 sense that it won't risk creating jerkiness due to duplicate frames when
5620 possible, but if there are bad edits or blended fields it will end up
5621 outputting combed frames when a good match might actually exist. On the other
5622 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
5623 but will almost always find a good frame if there is one. The other values are
5624 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
5625 jerkiness and creating duplicate frames versus finding good matches in sections
5626 with bad edits, orphaned fields, blended fields, etc.
5628 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
5630 Available values are:
5634 2-way matching (p/c)
5636 2-way matching, and trying 3rd match if still combed (p/c + n)
5638 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
5640 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
5641 still combed (p/c + n + u/b)
5643 3-way matching (p/c/n)
5645 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
5646 detected as combed (p/c/n + u/b)
5649 The parenthesis at the end indicate the matches that would be used for that
5650 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
5653 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
5656 Default value is @var{pc_n}.
5659 Mark the main input stream as a pre-processed input, and enable the secondary
5660 input stream as the clean source to pick the fields from. See the filter
5661 introduction for more details. It is similar to the @option{clip2} feature from
5664 Default value is @code{0} (disabled).
5667 Set the field to match from. It is recommended to set this to the same value as
5668 @option{order} unless you experience matching failures with that setting. In
5669 certain circumstances changing the field that is used to match from can have a
5670 large impact on matching performance. Available values are:
5674 Automatic (same value as @option{order}).
5676 Match from the bottom field.
5678 Match from the top field.
5681 Default value is @var{auto}.
5684 Set whether or not chroma is included during the match comparisons. In most
5685 cases it is recommended to leave this enabled. You should set this to @code{0}
5686 only if your clip has bad chroma problems such as heavy rainbowing or other
5687 artifacts. Setting this to @code{0} could also be used to speed things up at
5688 the cost of some accuracy.
5690 Default value is @code{1}.
5694 These define an exclusion band which excludes the lines between @option{y0} and
5695 @option{y1} from being included in the field matching decision. An exclusion
5696 band can be used to ignore subtitles, a logo, or other things that may
5697 interfere with the matching. @option{y0} sets the starting scan line and
5698 @option{y1} sets the ending line; all lines in between @option{y0} and
5699 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
5700 @option{y0} and @option{y1} to the same value will disable the feature.
5701 @option{y0} and @option{y1} defaults to @code{0}.
5704 Set the scene change detection threshold as a percentage of maximum change on
5705 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
5706 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
5707 @option{scthresh} is @code{[0.0, 100.0]}.
5709 Default value is @code{12.0}.
5712 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
5713 account the combed scores of matches when deciding what match to use as the
5714 final match. Available values are:
5718 No final matching based on combed scores.
5720 Combed scores are only used when a scene change is detected.
5722 Use combed scores all the time.
5725 Default is @var{sc}.
5728 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
5729 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
5730 Available values are:
5734 No forced calculation.
5736 Force p/c/n calculations.
5738 Force p/c/n/u/b calculations.
5741 Default value is @var{none}.
5744 This is the area combing threshold used for combed frame detection. This
5745 essentially controls how "strong" or "visible" combing must be to be detected.
5746 Larger values mean combing must be more visible and smaller values mean combing
5747 can be less visible or strong and still be detected. Valid settings are from
5748 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
5749 be detected as combed). This is basically a pixel difference value. A good
5750 range is @code{[8, 12]}.
5752 Default value is @code{9}.
5755 Sets whether or not chroma is considered in the combed frame decision. Only
5756 disable this if your source has chroma problems (rainbowing, etc.) that are
5757 causing problems for the combed frame detection with chroma enabled. Actually,
5758 using @option{chroma}=@var{0} is usually more reliable, except for the case
5759 where there is chroma only combing in the source.
5761 Default value is @code{0}.
5765 Respectively set the x-axis and y-axis size of the window used during combed
5766 frame detection. This has to do with the size of the area in which
5767 @option{combpel} pixels are required to be detected as combed for a frame to be
5768 declared combed. See the @option{combpel} parameter description for more info.
5769 Possible values are any number that is a power of 2 starting at 4 and going up
5772 Default value is @code{16}.
5775 The number of combed pixels inside any of the @option{blocky} by
5776 @option{blockx} size blocks on the frame for the frame to be detected as
5777 combed. While @option{cthresh} controls how "visible" the combing must be, this
5778 setting controls "how much" combing there must be in any localized area (a
5779 window defined by the @option{blockx} and @option{blocky} settings) on the
5780 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
5781 which point no frames will ever be detected as combed). This setting is known
5782 as @option{MI} in TFM/VFM vocabulary.
5784 Default value is @code{80}.
5787 @anchor{p/c/n/u/b meaning}
5788 @subsection p/c/n/u/b meaning
5790 @subsubsection p/c/n
5792 We assume the following telecined stream:
5795 Top fields: 1 2 2 3 4
5796 Bottom fields: 1 2 3 4 4
5799 The numbers correspond to the progressive frame the fields relate to. Here, the
5800 first two frames are progressive, the 3rd and 4th are combed, and so on.
5802 When @code{fieldmatch} is configured to run a matching from bottom
5803 (@option{field}=@var{bottom}) this is how this input stream get transformed:
5808 B 1 2 3 4 4 <-- matching reference
5817 As a result of the field matching, we can see that some frames get duplicated.
5818 To perform a complete inverse telecine, you need to rely on a decimation filter
5819 after this operation. See for instance the @ref{decimate} filter.
5821 The same operation now matching from top fields (@option{field}=@var{top})
5826 T 1 2 2 3 4 <-- matching reference
5836 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
5837 basically, they refer to the frame and field of the opposite parity:
5840 @item @var{p} matches the field of the opposite parity in the previous frame
5841 @item @var{c} matches the field of the opposite parity in the current frame
5842 @item @var{n} matches the field of the opposite parity in the next frame
5847 The @var{u} and @var{b} matching are a bit special in the sense that they match
5848 from the opposite parity flag. In the following examples, we assume that we are
5849 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
5850 'x' is placed above and below each matched fields.
5852 With bottom matching (@option{field}=@var{bottom}):
5857 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
5858 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
5866 With top matching (@option{field}=@var{top}):
5871 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
5872 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
5880 @subsection Examples
5882 Simple IVTC of a top field first telecined stream:
5884 fieldmatch=order=tff:combmatch=none, decimate
5887 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
5889 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
5894 Transform the field order of the input video.
5896 It accepts the following parameters:
5901 The output field order. Valid values are @var{tff} for top field first or @var{bff}
5902 for bottom field first.
5905 The default value is @samp{tff}.
5907 The transformation is done by shifting the picture content up or down
5908 by one line, and filling the remaining line with appropriate picture content.
5909 This method is consistent with most broadcast field order converters.
5911 If the input video is not flagged as being interlaced, or it is already
5912 flagged as being of the required output field order, then this filter does
5913 not alter the incoming video.
5915 It is very useful when converting to or from PAL DV material,
5916 which is bottom field first.
5920 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
5925 Buffer input images and send them when they are requested.
5927 It is mainly useful when auto-inserted by the libavfilter
5930 It does not take parameters.
5934 Find a rectangular object
5936 It accepts the following options:
5940 Filepath of the object image, needs to be in gray8.
5943 Detection threshold, default is 0.5.
5946 Number of mipmaps, default is 3.
5948 @item xmin, ymin, xmax, ymax
5949 Specifies the rectangle in which to search.
5952 @subsection Examples
5956 Generate a representative palette of a given video using @command{ffmpeg}:
5958 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
5964 Cover a rectangular object
5966 It accepts the following options:
5970 Filepath of the optional cover image, needs to be in yuv420.
5975 It accepts the following values:
5978 cover it by the supplied image
5980 cover it by interpolating the surrounding pixels
5983 Default value is @var{blur}.
5986 @subsection Examples
5990 Generate a representative palette of a given video using @command{ffmpeg}:
5992 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
5999 Convert the input video to one of the specified pixel formats.
6000 Libavfilter will try to pick one that is suitable as input to
6003 It accepts the following parameters:
6007 A '|'-separated list of pixel format names, such as
6008 "pix_fmts=yuv420p|monow|rgb24".
6012 @subsection Examples
6016 Convert the input video to the @var{yuv420p} format
6018 format=pix_fmts=yuv420p
6021 Convert the input video to any of the formats in the list
6023 format=pix_fmts=yuv420p|yuv444p|yuv410p
6030 Convert the video to specified constant frame rate by duplicating or dropping
6031 frames as necessary.
6033 It accepts the following parameters:
6037 The desired output frame rate. The default is @code{25}.
6042 Possible values are:
6045 zero round towards 0
6049 round towards -infinity
6051 round towards +infinity
6055 The default is @code{near}.
6058 Assume the first PTS should be the given value, in seconds. This allows for
6059 padding/trimming at the start of stream. By default, no assumption is made
6060 about the first frame's expected PTS, so no padding or trimming is done.
6061 For example, this could be set to 0 to pad the beginning with duplicates of
6062 the first frame if a video stream starts after the audio stream or to trim any
6063 frames with a negative PTS.
6067 Alternatively, the options can be specified as a flat string:
6068 @var{fps}[:@var{round}].
6070 See also the @ref{setpts} filter.
6072 @subsection Examples
6076 A typical usage in order to set the fps to 25:
6082 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
6084 fps=fps=film:round=near
6090 Pack two different video streams into a stereoscopic video, setting proper
6091 metadata on supported codecs. The two views should have the same size and
6092 framerate and processing will stop when the shorter video ends. Please note
6093 that you may conveniently adjust view properties with the @ref{scale} and
6096 It accepts the following parameters:
6100 The desired packing format. Supported values are:
6105 The views are next to each other (default).
6108 The views are on top of each other.
6111 The views are packed by line.
6114 The views are packed by column.
6117 The views are temporally interleaved.
6126 # Convert left and right views into a frame-sequential video
6127 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
6129 # Convert views into a side-by-side video with the same output resolution as the input
6130 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
6135 Change the frame rate by interpolating new video output frames from the source
6138 This filter is not designed to function correctly with interlaced media. If
6139 you wish to change the frame rate of interlaced media then you are required
6140 to deinterlace before this filter and re-interlace after this filter.
6142 A description of the accepted options follows.
6146 Specify the output frames per second. This option can also be specified
6147 as a value alone. The default is @code{50}.
6150 Specify the start of a range where the output frame will be created as a
6151 linear interpolation of two frames. The range is [@code{0}-@code{255}],
6152 the default is @code{15}.
6155 Specify the end of a range where the output frame will be created as a
6156 linear interpolation of two frames. The range is [@code{0}-@code{255}],
6157 the default is @code{240}.
6160 Specify the level at which a scene change is detected as a value between
6161 0 and 100 to indicate a new scene; a low value reflects a low
6162 probability for the current frame to introduce a new scene, while a higher
6163 value means the current frame is more likely to be one.
6164 The default is @code{7}.
6167 Specify flags influencing the filter process.
6169 Available value for @var{flags} is:
6172 @item scene_change_detect, scd
6173 Enable scene change detection using the value of the option @var{scene}.
6174 This flag is enabled by default.
6180 Select one frame every N-th frame.
6182 This filter accepts the following option:
6185 Select frame after every @code{step} frames.
6186 Allowed values are positive integers higher than 0. Default value is @code{1}.
6192 Apply a frei0r effect to the input video.
6194 To enable the compilation of this filter, you need to install the frei0r
6195 header and configure FFmpeg with @code{--enable-frei0r}.
6197 It accepts the following parameters:
6202 The name of the frei0r effect to load. If the environment variable
6203 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
6204 directories specified by the colon-separated list in @env{FREIOR_PATH}.
6205 Otherwise, the standard frei0r paths are searched, in this order:
6206 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
6207 @file{/usr/lib/frei0r-1/}.
6210 A '|'-separated list of parameters to pass to the frei0r effect.
6214 A frei0r effect parameter can be a boolean (its value is either
6215 "y" or "n"), a double, a color (specified as
6216 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
6217 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
6218 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
6219 @var{X} and @var{Y} are floating point numbers) and/or a string.
6221 The number and types of parameters depend on the loaded effect. If an
6222 effect parameter is not specified, the default value is set.
6224 @subsection Examples
6228 Apply the distort0r effect, setting the first two double parameters:
6230 frei0r=filter_name=distort0r:filter_params=0.5|0.01
6234 Apply the colordistance effect, taking a color as the first parameter:
6236 frei0r=colordistance:0.2/0.3/0.4
6237 frei0r=colordistance:violet
6238 frei0r=colordistance:0x112233
6242 Apply the perspective effect, specifying the top left and top right image
6245 frei0r=perspective:0.2/0.2|0.8/0.2
6249 For more information, see
6250 @url{http://frei0r.dyne.org}
6254 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
6256 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
6257 processing filter, one of them is performed once per block, not per pixel.
6258 This allows for much higher speed.
6260 The filter accepts the following options:
6264 Set quality. This option defines the number of levels for averaging. It accepts
6265 an integer in the range 4-5. Default value is @code{4}.
6268 Force a constant quantization parameter. It accepts an integer in range 0-63.
6269 If not set, the filter will use the QP from the video stream (if available).
6272 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
6273 more details but also more artifacts, while higher values make the image smoother
6274 but also blurrier. Default value is @code{0} − PSNR optimal.
6277 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
6278 option may cause flicker since the B-Frames have often larger QP. Default is
6279 @code{0} (not enabled).
6285 The filter accepts the following options:
6289 Set the luminance expression.
6291 Set the chrominance blue expression.
6293 Set the chrominance red expression.
6295 Set the alpha expression.
6297 Set the red expression.
6299 Set the green expression.
6301 Set the blue expression.
6304 The colorspace is selected according to the specified options. If one
6305 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
6306 options is specified, the filter will automatically select a YCbCr
6307 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
6308 @option{blue_expr} options is specified, it will select an RGB
6311 If one of the chrominance expression is not defined, it falls back on the other
6312 one. If no alpha expression is specified it will evaluate to opaque value.
6313 If none of chrominance expressions are specified, they will evaluate
6314 to the luminance expression.
6316 The expressions can use the following variables and functions:
6320 The sequential number of the filtered frame, starting from @code{0}.
6324 The coordinates of the current sample.
6328 The width and height of the image.
6332 Width and height scale depending on the currently filtered plane. It is the
6333 ratio between the corresponding luma plane number of pixels and the current
6334 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
6335 @code{0.5,0.5} for chroma planes.
6338 Time of the current frame, expressed in seconds.
6341 Return the value of the pixel at location (@var{x},@var{y}) of the current
6345 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
6349 Return the value of the pixel at location (@var{x},@var{y}) of the
6350 blue-difference chroma plane. Return 0 if there is no such plane.
6353 Return the value of the pixel at location (@var{x},@var{y}) of the
6354 red-difference chroma plane. Return 0 if there is no such plane.
6359 Return the value of the pixel at location (@var{x},@var{y}) of the
6360 red/green/blue component. Return 0 if there is no such component.
6363 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
6364 plane. Return 0 if there is no such plane.
6367 For functions, if @var{x} and @var{y} are outside the area, the value will be
6368 automatically clipped to the closer edge.
6370 @subsection Examples
6374 Flip the image horizontally:
6380 Generate a bidimensional sine wave, with angle @code{PI/3} and a
6381 wavelength of 100 pixels:
6383 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
6387 Generate a fancy enigmatic moving light:
6389 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
6393 Generate a quick emboss effect:
6395 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
6399 Modify RGB components depending on pixel position:
6401 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
6405 Create a radial gradient that is the same size as the input (also see
6406 the @ref{vignette} filter):
6408 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
6412 Create a linear gradient to use as a mask for another filter, then
6413 compose with @ref{overlay}. In this example the video will gradually
6414 become more blurry from the top to the bottom of the y-axis as defined
6415 by the linear gradient:
6417 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
6423 Fix the banding artifacts that are sometimes introduced into nearly flat
6424 regions by truncation to 8bit color depth.
6425 Interpolate the gradients that should go where the bands are, and
6428 It is designed for playback only. Do not use it prior to
6429 lossy compression, because compression tends to lose the dither and
6430 bring back the bands.
6432 It accepts the following parameters:
6437 The maximum amount by which the filter will change any one pixel. This is also
6438 the threshold for detecting nearly flat regions. Acceptable values range from
6439 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
6443 The neighborhood to fit the gradient to. A larger radius makes for smoother
6444 gradients, but also prevents the filter from modifying the pixels near detailed
6445 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
6446 values will be clipped to the valid range.
6450 Alternatively, the options can be specified as a flat string:
6451 @var{strength}[:@var{radius}]
6453 @subsection Examples
6457 Apply the filter with a @code{3.5} strength and radius of @code{8}:
6463 Specify radius, omitting the strength (which will fall-back to the default
6474 Apply a Hald CLUT to a video stream.
6476 First input is the video stream to process, and second one is the Hald CLUT.
6477 The Hald CLUT input can be a simple picture or a complete video stream.
6479 The filter accepts the following options:
6483 Force termination when the shortest input terminates. Default is @code{0}.
6485 Continue applying the last CLUT after the end of the stream. A value of
6486 @code{0} disable the filter after the last frame of the CLUT is reached.
6487 Default is @code{1}.
6490 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
6491 filters share the same internals).
6493 More information about the Hald CLUT can be found on Eskil Steenberg's website
6494 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
6496 @subsection Workflow examples
6498 @subsubsection Hald CLUT video stream
6500 Generate an identity Hald CLUT stream altered with various effects:
6502 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
6505 Note: make sure you use a lossless codec.
6507 Then use it with @code{haldclut} to apply it on some random stream:
6509 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
6512 The Hald CLUT will be applied to the 10 first seconds (duration of
6513 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
6514 to the remaining frames of the @code{mandelbrot} stream.
6516 @subsubsection Hald CLUT with preview
6518 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
6519 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
6520 biggest possible square starting at the top left of the picture. The remaining
6521 padding pixels (bottom or right) will be ignored. This area can be used to add
6522 a preview of the Hald CLUT.
6524 Typically, the following generated Hald CLUT will be supported by the
6525 @code{haldclut} filter:
6528 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
6529 pad=iw+320 [padded_clut];
6530 smptebars=s=320x256, split [a][b];
6531 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
6532 [main][b] overlay=W-320" -frames:v 1 clut.png
6535 It contains the original and a preview of the effect of the CLUT: SMPTE color
6536 bars are displayed on the right-top, and below the same color bars processed by
6539 Then, the effect of this Hald CLUT can be visualized with:
6541 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
6546 Flip the input video horizontally.
6548 For example, to horizontally flip the input video with @command{ffmpeg}:
6550 ffmpeg -i in.avi -vf "hflip" out.avi
6554 This filter applies a global color histogram equalization on a
6557 It can be used to correct video that has a compressed range of pixel
6558 intensities. The filter redistributes the pixel intensities to
6559 equalize their distribution across the intensity range. It may be
6560 viewed as an "automatically adjusting contrast filter". This filter is
6561 useful only for correcting degraded or poorly captured source
6564 The filter accepts the following options:
6568 Determine the amount of equalization to be applied. As the strength
6569 is reduced, the distribution of pixel intensities more-and-more
6570 approaches that of the input frame. The value must be a float number
6571 in the range [0,1] and defaults to 0.200.
6574 Set the maximum intensity that can generated and scale the output
6575 values appropriately. The strength should be set as desired and then
6576 the intensity can be limited if needed to avoid washing-out. The value
6577 must be a float number in the range [0,1] and defaults to 0.210.
6580 Set the antibanding level. If enabled the filter will randomly vary
6581 the luminance of output pixels by a small amount to avoid banding of
6582 the histogram. Possible values are @code{none}, @code{weak} or
6583 @code{strong}. It defaults to @code{none}.
6588 Compute and draw a color distribution histogram for the input video.
6590 The computed histogram is a representation of the color component
6591 distribution in an image.
6593 The filter accepts the following options:
6599 It accepts the following values:
6602 Standard histogram that displays the color components distribution in an
6603 image. Displays color graph for each color component. Shows distribution of
6604 the Y, U, V, A or R, G, B components, depending on input format, in the
6605 current frame. Below each graph a color component scale meter is shown.
6608 Displays chroma values (U/V color placement) in a two dimensional
6609 graph (which is called a vectorscope). The brighter a pixel in the
6610 vectorscope, the more pixels of the input frame correspond to that pixel
6611 (i.e., more pixels have this chroma value). The V component is displayed on
6612 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
6613 side being V = 255. The U component is displayed on the vertical (Y) axis,
6614 with the top representing U = 0 and the bottom representing U = 255.
6616 The position of a white pixel in the graph corresponds to the chroma value of
6617 a pixel of the input clip. The graph can therefore be used to read the hue
6618 (color flavor) and the saturation (the dominance of the hue in the color). As
6619 the hue of a color changes, it moves around the square. At the center of the
6620 square the saturation is zero, which means that the corresponding pixel has no
6621 color. If the amount of a specific color is increased (while leaving the other
6622 colors unchanged) the saturation increases, and the indicator moves towards
6623 the edge of the square.
6626 Chroma values in vectorscope, similar as @code{color} but actual chroma values
6630 Per row/column color component graph. In row mode, the graph on the left side
6631 represents color component value 0 and the right side represents value = 255.
6632 In column mode, the top side represents color component value = 0 and bottom
6633 side represents value = 255.
6635 Default value is @code{levels}.
6638 Set height of level in @code{levels}. Default value is @code{200}.
6639 Allowed range is [50, 2048].
6642 Set height of color scale in @code{levels}. Default value is @code{12}.
6643 Allowed range is [0, 40].
6646 Set step for @code{waveform} mode. Smaller values are useful to find out how
6647 many values of the same luminance are distributed across input rows/columns.
6648 Default value is @code{10}. Allowed range is [1, 255].
6651 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
6652 Default is @code{row}.
6654 @item waveform_mirror
6655 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
6656 means mirrored. In mirrored mode, higher values will be represented on the left
6657 side for @code{row} mode and at the top for @code{column} mode. Default is
6658 @code{0} (unmirrored).
6661 Set display mode for @code{waveform} and @code{levels}.
6662 It accepts the following values:
6665 Display separate graph for the color components side by side in
6666 @code{row} waveform mode or one below the other in @code{column} waveform mode
6667 for @code{waveform} histogram mode. For @code{levels} histogram mode,
6668 per color component graphs are placed below each other.
6670 Using this display mode in @code{waveform} histogram mode makes it easy to
6671 spot color casts in the highlights and shadows of an image, by comparing the
6672 contours of the top and the bottom graphs of each waveform. Since whites,
6673 grays, and blacks are characterized by exactly equal amounts of red, green,
6674 and blue, neutral areas of the picture should display three waveforms of
6675 roughly equal width/height. If not, the correction is easy to perform by
6676 making level adjustments the three waveforms.
6679 Presents information identical to that in the @code{parade}, except
6680 that the graphs representing color components are superimposed directly
6683 This display mode in @code{waveform} histogram mode makes it easier to spot
6684 relative differences or similarities in overlapping areas of the color
6685 components that are supposed to be identical, such as neutral whites, grays,
6688 Default is @code{parade}.
6691 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
6692 Default is @code{linear}.
6695 Set what color components to display for mode @code{levels}.
6696 Default is @code{7}.
6699 @subsection Examples
6704 Calculate and draw histogram:
6706 ffplay -i input -vf histogram
6714 This is a high precision/quality 3d denoise filter. It aims to reduce
6715 image noise, producing smooth images and making still images really
6716 still. It should enhance compressibility.
6718 It accepts the following optional parameters:
6722 A non-negative floating point number which specifies spatial luma strength.
6725 @item chroma_spatial
6726 A non-negative floating point number which specifies spatial chroma strength.
6727 It defaults to 3.0*@var{luma_spatial}/4.0.
6730 A floating point number which specifies luma temporal strength. It defaults to
6731 6.0*@var{luma_spatial}/4.0.
6734 A floating point number which specifies chroma temporal strength. It defaults to
6735 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
6740 Apply a high-quality magnification filter designed for pixel art. This filter
6741 was originally created by Maxim Stepin.
6743 It accepts the following option:
6747 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
6748 @code{hq3x} and @code{4} for @code{hq4x}.
6749 Default is @code{3}.
6753 Stack input videos horizontally.
6755 All streams must be of same pixel format and of same height.
6757 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
6758 to create same output.
6760 The filter accept the following option:
6764 Set number of input streams. Default is 2.
6769 Modify the hue and/or the saturation of the input.
6771 It accepts the following parameters:
6775 Specify the hue angle as a number of degrees. It accepts an expression,
6776 and defaults to "0".
6779 Specify the saturation in the [-10,10] range. It accepts an expression and
6783 Specify the hue angle as a number of radians. It accepts an
6784 expression, and defaults to "0".
6787 Specify the brightness in the [-10,10] range. It accepts an expression and
6791 @option{h} and @option{H} are mutually exclusive, and can't be
6792 specified at the same time.
6794 The @option{b}, @option{h}, @option{H} and @option{s} option values are
6795 expressions containing the following constants:
6799 frame count of the input frame starting from 0
6802 presentation timestamp of the input frame expressed in time base units
6805 frame rate of the input video, NAN if the input frame rate is unknown
6808 timestamp expressed in seconds, NAN if the input timestamp is unknown
6811 time base of the input video
6814 @subsection Examples
6818 Set the hue to 90 degrees and the saturation to 1.0:
6824 Same command but expressing the hue in radians:
6830 Rotate hue and make the saturation swing between 0
6831 and 2 over a period of 1 second:
6833 hue="H=2*PI*t: s=sin(2*PI*t)+1"
6837 Apply a 3 seconds saturation fade-in effect starting at 0:
6842 The general fade-in expression can be written as:
6844 hue="s=min(0\, max((t-START)/DURATION\, 1))"
6848 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
6850 hue="s=max(0\, min(1\, (8-t)/3))"
6853 The general fade-out expression can be written as:
6855 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
6860 @subsection Commands
6862 This filter supports the following commands:
6868 Modify the hue and/or the saturation and/or brightness of the input video.
6869 The command accepts the same syntax of the corresponding option.
6871 If the specified expression is not valid, it is kept at its current
6877 Detect video interlacing type.
6879 This filter tries to detect if the input frames as interlaced, progressive,
6880 top or bottom field first. It will also try and detect fields that are
6881 repeated between adjacent frames (a sign of telecine).
6883 Single frame detection considers only immediately adjacent frames when classifying each frame.
6884 Multiple frame detection incorporates the classification history of previous frames.
6886 The filter will log these metadata values:
6889 @item single.current_frame
6890 Detected type of current frame using single-frame detection. One of:
6891 ``tff'' (top field first), ``bff'' (bottom field first),
6892 ``progressive'', or ``undetermined''
6895 Cumulative number of frames detected as top field first using single-frame detection.
6898 Cumulative number of frames detected as top field first using multiple-frame detection.
6901 Cumulative number of frames detected as bottom field first using single-frame detection.
6903 @item multiple.current_frame
6904 Detected type of current frame using multiple-frame detection. One of:
6905 ``tff'' (top field first), ``bff'' (bottom field first),
6906 ``progressive'', or ``undetermined''
6909 Cumulative number of frames detected as bottom field first using multiple-frame detection.
6911 @item single.progressive
6912 Cumulative number of frames detected as progressive using single-frame detection.
6914 @item multiple.progressive
6915 Cumulative number of frames detected as progressive using multiple-frame detection.
6917 @item single.undetermined
6918 Cumulative number of frames that could not be classified using single-frame detection.
6920 @item multiple.undetermined
6921 Cumulative number of frames that could not be classified using multiple-frame detection.
6923 @item repeated.current_frame
6924 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
6926 @item repeated.neither
6927 Cumulative number of frames with no repeated field.
6930 Cumulative number of frames with the top field repeated from the previous frame's top field.
6932 @item repeated.bottom
6933 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
6936 The filter accepts the following options:
6940 Set interlacing threshold.
6942 Set progressive threshold.
6944 Threshold for repeated field detection.
6946 Number of frames after which a given frame's contribution to the
6947 statistics is halved (i.e., it contributes only 0.5 to it's
6948 classification). The default of 0 means that all frames seen are given
6949 full weight of 1.0 forever.
6950 @item analyze_interlaced_flag
6951 When this is not 0 then idet will use the specified number of frames to determine
6952 if the interlaced flag is accurate, it will not count undetermined frames.
6953 If the flag is found to be accurate it will be used without any further
6954 computations, if it is found to be inaccurate it will be cleared without any
6955 further computations. This allows inserting the idet filter as a low computational
6956 method to clean up the interlaced flag
6961 Deinterleave or interleave fields.
6963 This filter allows one to process interlaced images fields without
6964 deinterlacing them. Deinterleaving splits the input frame into 2
6965 fields (so called half pictures). Odd lines are moved to the top
6966 half of the output image, even lines to the bottom half.
6967 You can process (filter) them independently and then re-interleave them.
6969 The filter accepts the following options:
6973 @item chroma_mode, c
6975 Available values for @var{luma_mode}, @var{chroma_mode} and
6976 @var{alpha_mode} are:
6982 @item deinterleave, d
6983 Deinterleave fields, placing one above the other.
6986 Interleave fields. Reverse the effect of deinterleaving.
6988 Default value is @code{none}.
6991 @item chroma_swap, cs
6992 @item alpha_swap, as
6993 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
6998 Apply inflate effect to the video.
7000 This filter replaces the pixel by the local(3x3) average by taking into account
7001 only values higher than the pixel.
7003 It accepts the following options:
7010 Allows to limit the maximum change for each plane, default is 65535.
7011 If 0, plane will remain unchanged.
7016 Simple interlacing filter from progressive contents. This interleaves upper (or
7017 lower) lines from odd frames with lower (or upper) lines from even frames,
7018 halving the frame rate and preserving image height.
7021 Original Original New Frame
7022 Frame 'j' Frame 'j+1' (tff)
7023 ========== =========== ==================
7024 Line 0 --------------------> Frame 'j' Line 0
7025 Line 1 Line 1 ----> Frame 'j+1' Line 1
7026 Line 2 ---------------------> Frame 'j' Line 2
7027 Line 3 Line 3 ----> Frame 'j+1' Line 3
7029 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
7032 It accepts the following optional parameters:
7036 This determines whether the interlaced frame is taken from the even
7037 (tff - default) or odd (bff) lines of the progressive frame.
7040 Enable (default) or disable the vertical lowpass filter to avoid twitter
7041 interlacing and reduce moire patterns.
7046 Deinterlace input video by applying Donald Graft's adaptive kernel
7047 deinterling. Work on interlaced parts of a video to produce
7050 The description of the accepted parameters follows.
7054 Set the threshold which affects the filter's tolerance when
7055 determining if a pixel line must be processed. It must be an integer
7056 in the range [0,255] and defaults to 10. A value of 0 will result in
7057 applying the process on every pixels.
7060 Paint pixels exceeding the threshold value to white if set to 1.
7064 Set the fields order. Swap fields if set to 1, leave fields alone if
7068 Enable additional sharpening if set to 1. Default is 0.
7071 Enable twoway sharpening if set to 1. Default is 0.
7074 @subsection Examples
7078 Apply default values:
7080 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
7084 Enable additional sharpening:
7090 Paint processed pixels in white:
7096 @section lenscorrection
7098 Correct radial lens distortion
7100 This filter can be used to correct for radial distortion as can result from the use
7101 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
7102 one can use tools available for example as part of opencv or simply trial-and-error.
7103 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
7104 and extract the k1 and k2 coefficients from the resulting matrix.
7106 Note that effectively the same filter is available in the open-source tools Krita and
7107 Digikam from the KDE project.
7109 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
7110 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
7111 brightness distribution, so you may want to use both filters together in certain
7112 cases, though you will have to take care of ordering, i.e. whether vignetting should
7113 be applied before or after lens correction.
7117 The filter accepts the following options:
7121 Relative x-coordinate of the focal point of the image, and thereby the center of the
7122 distortion. This value has a range [0,1] and is expressed as fractions of the image
7125 Relative y-coordinate of the focal point of the image, and thereby the center of the
7126 distortion. This value has a range [0,1] and is expressed as fractions of the image
7129 Coefficient of the quadratic correction term. 0.5 means no correction.
7131 Coefficient of the double quadratic correction term. 0.5 means no correction.
7134 The formula that generates the correction is:
7136 @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)
7138 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
7139 distances from the focal point in the source and target images, respectively.
7144 Apply a 3D LUT to an input video.
7146 The filter accepts the following options:
7150 Set the 3D LUT file name.
7152 Currently supported formats:
7164 Select interpolation mode.
7166 Available values are:
7170 Use values from the nearest defined point.
7172 Interpolate values using the 8 points defining a cube.
7174 Interpolate values using a tetrahedron.
7178 @section lut, lutrgb, lutyuv
7180 Compute a look-up table for binding each pixel component input value
7181 to an output value, and apply it to the input video.
7183 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
7184 to an RGB input video.
7186 These filters accept the following parameters:
7189 set first pixel component expression
7191 set second pixel component expression
7193 set third pixel component expression
7195 set fourth pixel component expression, corresponds to the alpha component
7198 set red component expression
7200 set green component expression
7202 set blue component expression
7204 alpha component expression
7207 set Y/luminance component expression
7209 set U/Cb component expression
7211 set V/Cr component expression
7214 Each of them specifies the expression to use for computing the lookup table for
7215 the corresponding pixel component values.
7217 The exact component associated to each of the @var{c*} options depends on the
7220 The @var{lut} filter requires either YUV or RGB pixel formats in input,
7221 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
7223 The expressions can contain the following constants and functions:
7228 The input width and height.
7231 The input value for the pixel component.
7234 The input value, clipped to the @var{minval}-@var{maxval} range.
7237 The maximum value for the pixel component.
7240 The minimum value for the pixel component.
7243 The negated value for the pixel component value, clipped to the
7244 @var{minval}-@var{maxval} range; it corresponds to the expression
7245 "maxval-clipval+minval".
7248 The computed value in @var{val}, clipped to the
7249 @var{minval}-@var{maxval} range.
7251 @item gammaval(gamma)
7252 The computed gamma correction value of the pixel component value,
7253 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
7255 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
7259 All expressions default to "val".
7261 @subsection Examples
7267 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
7268 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
7271 The above is the same as:
7273 lutrgb="r=negval:g=negval:b=negval"
7274 lutyuv="y=negval:u=negval:v=negval"
7284 Remove chroma components, turning the video into a graytone image:
7286 lutyuv="u=128:v=128"
7290 Apply a luma burning effect:
7296 Remove green and blue components:
7302 Set a constant alpha channel value on input:
7304 format=rgba,lutrgb=a="maxval-minval/2"
7308 Correct luminance gamma by a factor of 0.5:
7310 lutyuv=y=gammaval(0.5)
7314 Discard least significant bits of luma:
7316 lutyuv=y='bitand(val, 128+64+32)'
7320 @section mergeplanes
7322 Merge color channel components from several video streams.
7324 The filter accepts up to 4 input streams, and merge selected input
7325 planes to the output video.
7327 This filter accepts the following options:
7330 Set input to output plane mapping. Default is @code{0}.
7332 The mappings is specified as a bitmap. It should be specified as a
7333 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
7334 mapping for the first plane of the output stream. 'A' sets the number of
7335 the input stream to use (from 0 to 3), and 'a' the plane number of the
7336 corresponding input to use (from 0 to 3). The rest of the mappings is
7337 similar, 'Bb' describes the mapping for the output stream second
7338 plane, 'Cc' describes the mapping for the output stream third plane and
7339 'Dd' describes the mapping for the output stream fourth plane.
7342 Set output pixel format. Default is @code{yuva444p}.
7345 @subsection Examples
7349 Merge three gray video streams of same width and height into single video stream:
7351 [a0][a1][a2]mergeplanes=0x001020:yuv444p
7355 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
7357 [a0][a1]mergeplanes=0x00010210:yuva444p
7361 Swap Y and A plane in yuva444p stream:
7363 format=yuva444p,mergeplanes=0x03010200:yuva444p
7367 Swap U and V plane in yuv420p stream:
7369 format=yuv420p,mergeplanes=0x000201:yuv420p
7373 Cast a rgb24 clip to yuv444p:
7375 format=rgb24,mergeplanes=0x000102:yuv444p
7381 Apply motion-compensation deinterlacing.
7383 It needs one field per frame as input and must thus be used together
7384 with yadif=1/3 or equivalent.
7386 This filter accepts the following options:
7389 Set the deinterlacing mode.
7391 It accepts one of the following values:
7396 use iterative motion estimation
7398 like @samp{slow}, but use multiple reference frames.
7400 Default value is @samp{fast}.
7403 Set the picture field parity assumed for the input video. It must be
7404 one of the following values:
7408 assume top field first
7410 assume bottom field first
7413 Default value is @samp{bff}.
7416 Set per-block quantization parameter (QP) used by the internal
7419 Higher values should result in a smoother motion vector field but less
7420 optimal individual vectors. Default value is 1.
7425 Drop frames that do not differ greatly from the previous frame in
7426 order to reduce frame rate.
7428 The main use of this filter is for very-low-bitrate encoding
7429 (e.g. streaming over dialup modem), but it could in theory be used for
7430 fixing movies that were inverse-telecined incorrectly.
7432 A description of the accepted options follows.
7436 Set the maximum number of consecutive frames which can be dropped (if
7437 positive), or the minimum interval between dropped frames (if
7438 negative). If the value is 0, the frame is dropped unregarding the
7439 number of previous sequentially dropped frames.
7446 Set the dropping threshold values.
7448 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
7449 represent actual pixel value differences, so a threshold of 64
7450 corresponds to 1 unit of difference for each pixel, or the same spread
7451 out differently over the block.
7453 A frame is a candidate for dropping if no 8x8 blocks differ by more
7454 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
7455 meaning the whole image) differ by more than a threshold of @option{lo}.
7457 Default value for @option{hi} is 64*12, default value for @option{lo} is
7458 64*5, and default value for @option{frac} is 0.33.
7466 It accepts an integer in input; if non-zero it negates the
7467 alpha component (if available). The default value in input is 0.
7471 Force libavfilter not to use any of the specified pixel formats for the
7472 input to the next filter.
7474 It accepts the following parameters:
7478 A '|'-separated list of pixel format names, such as
7479 apix_fmts=yuv420p|monow|rgb24".
7483 @subsection Examples
7487 Force libavfilter to use a format different from @var{yuv420p} for the
7488 input to the vflip filter:
7490 noformat=pix_fmts=yuv420p,vflip
7494 Convert the input video to any of the formats not contained in the list:
7496 noformat=yuv420p|yuv444p|yuv410p
7502 Add noise on video input frame.
7504 The filter accepts the following options:
7512 Set noise seed for specific pixel component or all pixel components in case
7513 of @var{all_seed}. Default value is @code{123457}.
7515 @item all_strength, alls
7516 @item c0_strength, c0s
7517 @item c1_strength, c1s
7518 @item c2_strength, c2s
7519 @item c3_strength, c3s
7520 Set noise strength for specific pixel component or all pixel components in case
7521 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
7523 @item all_flags, allf
7528 Set pixel component flags or set flags for all components if @var{all_flags}.
7529 Available values for component flags are:
7532 averaged temporal noise (smoother)
7534 mix random noise with a (semi)regular pattern
7536 temporal noise (noise pattern changes between frames)
7538 uniform noise (gaussian otherwise)
7542 @subsection Examples
7544 Add temporal and uniform noise to input video:
7546 noise=alls=20:allf=t+u
7551 Pass the video source unchanged to the output.
7554 Optical Character Recognition
7556 This filter uses Tesseract for optical character recognition.
7558 It accepts the following options:
7562 Set datapath to tesseract data. Default is to use whatever was
7563 set at installation.
7566 Set language, default is "eng".
7569 Set character whitelist.
7572 Set character blacklist.
7575 The filter exports recognized text as the frame metadata @code{lavfi.ocr.text}.
7579 Apply a video transform using libopencv.
7581 To enable this filter, install the libopencv library and headers and
7582 configure FFmpeg with @code{--enable-libopencv}.
7584 It accepts the following parameters:
7589 The name of the libopencv filter to apply.
7592 The parameters to pass to the libopencv filter. If not specified, the default
7597 Refer to the official libopencv documentation for more precise
7599 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
7601 Several libopencv filters are supported; see the following subsections.
7606 Dilate an image by using a specific structuring element.
7607 It corresponds to the libopencv function @code{cvDilate}.
7609 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
7611 @var{struct_el} represents a structuring element, and has the syntax:
7612 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
7614 @var{cols} and @var{rows} represent the number of columns and rows of
7615 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
7616 point, and @var{shape} the shape for the structuring element. @var{shape}
7617 must be "rect", "cross", "ellipse", or "custom".
7619 If the value for @var{shape} is "custom", it must be followed by a
7620 string of the form "=@var{filename}". The file with name
7621 @var{filename} is assumed to represent a binary image, with each
7622 printable character corresponding to a bright pixel. When a custom
7623 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
7624 or columns and rows of the read file are assumed instead.
7626 The default value for @var{struct_el} is "3x3+0x0/rect".
7628 @var{nb_iterations} specifies the number of times the transform is
7629 applied to the image, and defaults to 1.
7633 # Use the default values
7636 # Dilate using a structuring element with a 5x5 cross, iterating two times
7637 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
7639 # Read the shape from the file diamond.shape, iterating two times.
7640 # The file diamond.shape may contain a pattern of characters like this
7646 # The specified columns and rows are ignored
7647 # but the anchor point coordinates are not
7648 ocv=dilate:0x0+2x2/custom=diamond.shape|2
7653 Erode an image by using a specific structuring element.
7654 It corresponds to the libopencv function @code{cvErode}.
7656 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
7657 with the same syntax and semantics as the @ref{dilate} filter.
7661 Smooth the input video.
7663 The filter takes the following parameters:
7664 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
7666 @var{type} is the type of smooth filter to apply, and must be one of
7667 the following values: "blur", "blur_no_scale", "median", "gaussian",
7668 or "bilateral". The default value is "gaussian".
7670 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
7671 depend on the smooth type. @var{param1} and
7672 @var{param2} accept integer positive values or 0. @var{param3} and
7673 @var{param4} accept floating point values.
7675 The default value for @var{param1} is 3. The default value for the
7676 other parameters is 0.
7678 These parameters correspond to the parameters assigned to the
7679 libopencv function @code{cvSmooth}.
7684 Overlay one video on top of another.
7686 It takes two inputs and has one output. The first input is the "main"
7687 video on which the second input is overlaid.
7689 It accepts the following parameters:
7691 A description of the accepted options follows.
7696 Set the expression for the x and y coordinates of the overlaid video
7697 on the main video. Default value is "0" for both expressions. In case
7698 the expression is invalid, it is set to a huge value (meaning that the
7699 overlay will not be displayed within the output visible area).
7702 The action to take when EOF is encountered on the secondary input; it accepts
7703 one of the following values:
7707 Repeat the last frame (the default).
7711 Pass the main input through.
7715 Set when the expressions for @option{x}, and @option{y} are evaluated.
7717 It accepts the following values:
7720 only evaluate expressions once during the filter initialization or
7721 when a command is processed
7724 evaluate expressions for each incoming frame
7727 Default value is @samp{frame}.
7730 If set to 1, force the output to terminate when the shortest input
7731 terminates. Default value is 0.
7734 Set the format for the output video.
7736 It accepts the following values:
7751 Default value is @samp{yuv420}.
7753 @item rgb @emph{(deprecated)}
7754 If set to 1, force the filter to accept inputs in the RGB
7755 color space. Default value is 0. This option is deprecated, use
7756 @option{format} instead.
7759 If set to 1, force the filter to draw the last overlay frame over the
7760 main input until the end of the stream. A value of 0 disables this
7761 behavior. Default value is 1.
7764 The @option{x}, and @option{y} expressions can contain the following
7770 The main input width and height.
7774 The overlay input width and height.
7778 The computed values for @var{x} and @var{y}. They are evaluated for
7783 horizontal and vertical chroma subsample values of the output
7784 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
7788 the number of input frame, starting from 0
7791 the position in the file of the input frame, NAN if unknown
7794 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
7798 Note that the @var{n}, @var{pos}, @var{t} variables are available only
7799 when evaluation is done @emph{per frame}, and will evaluate to NAN
7800 when @option{eval} is set to @samp{init}.
7802 Be aware that frames are taken from each input video in timestamp
7803 order, hence, if their initial timestamps differ, it is a good idea
7804 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
7805 have them begin in the same zero timestamp, as the example for
7806 the @var{movie} filter does.
7808 You can chain together more overlays but you should test the
7809 efficiency of such approach.
7811 @subsection Commands
7813 This filter supports the following commands:
7817 Modify the x and y of the overlay input.
7818 The command accepts the same syntax of the corresponding option.
7820 If the specified expression is not valid, it is kept at its current
7824 @subsection Examples
7828 Draw the overlay at 10 pixels from the bottom right corner of the main
7831 overlay=main_w-overlay_w-10:main_h-overlay_h-10
7834 Using named options the example above becomes:
7836 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
7840 Insert a transparent PNG logo in the bottom left corner of the input,
7841 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
7843 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
7847 Insert 2 different transparent PNG logos (second logo on bottom
7848 right corner) using the @command{ffmpeg} tool:
7850 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
7854 Add a transparent color layer on top of the main video; @code{WxH}
7855 must specify the size of the main input to the overlay filter:
7857 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
7861 Play an original video and a filtered version (here with the deshake
7862 filter) side by side using the @command{ffplay} tool:
7864 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
7867 The above command is the same as:
7869 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
7873 Make a sliding overlay appearing from the left to the right top part of the
7874 screen starting since time 2:
7876 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
7880 Compose output by putting two input videos side to side:
7882 ffmpeg -i left.avi -i right.avi -filter_complex "
7883 nullsrc=size=200x100 [background];
7884 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
7885 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
7886 [background][left] overlay=shortest=1 [background+left];
7887 [background+left][right] overlay=shortest=1:x=100 [left+right]
7892 Mask 10-20 seconds of a video by applying the delogo filter to a section
7894 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
7895 -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]'
7900 Chain several overlays in cascade:
7902 nullsrc=s=200x200 [bg];
7903 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
7904 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
7905 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
7906 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
7907 [in3] null, [mid2] overlay=100:100 [out0]
7914 Apply Overcomplete Wavelet denoiser.
7916 The filter accepts the following options:
7922 Larger depth values will denoise lower frequency components more, but
7923 slow down filtering.
7925 Must be an int in the range 8-16, default is @code{8}.
7927 @item luma_strength, ls
7930 Must be a double value in the range 0-1000, default is @code{1.0}.
7932 @item chroma_strength, cs
7933 Set chroma strength.
7935 Must be a double value in the range 0-1000, default is @code{1.0}.
7941 Add paddings to the input image, and place the original input at the
7942 provided @var{x}, @var{y} coordinates.
7944 It accepts the following parameters:
7949 Specify an expression for the size of the output image with the
7950 paddings added. If the value for @var{width} or @var{height} is 0, the
7951 corresponding input size is used for the output.
7953 The @var{width} expression can reference the value set by the
7954 @var{height} expression, and vice versa.
7956 The default value of @var{width} and @var{height} is 0.
7960 Specify the offsets to place the input image at within the padded area,
7961 with respect to the top/left border of the output image.
7963 The @var{x} expression can reference the value set by the @var{y}
7964 expression, and vice versa.
7966 The default value of @var{x} and @var{y} is 0.
7969 Specify the color of the padded area. For the syntax of this option,
7970 check the "Color" section in the ffmpeg-utils manual.
7972 The default value of @var{color} is "black".
7975 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
7976 options are expressions containing the following constants:
7981 The input video width and height.
7985 These are the same as @var{in_w} and @var{in_h}.
7989 The output width and height (the size of the padded area), as
7990 specified by the @var{width} and @var{height} expressions.
7994 These are the same as @var{out_w} and @var{out_h}.
7998 The x and y offsets as specified by the @var{x} and @var{y}
7999 expressions, or NAN if not yet specified.
8002 same as @var{iw} / @var{ih}
8005 input sample aspect ratio
8008 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
8012 The horizontal and vertical chroma subsample values. For example for the
8013 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
8016 @subsection Examples
8020 Add paddings with the color "violet" to the input video. The output video
8021 size is 640x480, and the top-left corner of the input video is placed at
8024 pad=640:480:0:40:violet
8027 The example above is equivalent to the following command:
8029 pad=width=640:height=480:x=0:y=40:color=violet
8033 Pad the input to get an output with dimensions increased by 3/2,
8034 and put the input video at the center of the padded area:
8036 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
8040 Pad the input to get a squared output with size equal to the maximum
8041 value between the input width and height, and put the input video at
8042 the center of the padded area:
8044 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
8048 Pad the input to get a final w/h ratio of 16:9:
8050 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
8054 In case of anamorphic video, in order to set the output display aspect
8055 correctly, it is necessary to use @var{sar} in the expression,
8056 according to the relation:
8058 (ih * X / ih) * sar = output_dar
8059 X = output_dar / sar
8062 Thus the previous example needs to be modified to:
8064 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
8068 Double the output size and put the input video in the bottom-right
8069 corner of the output padded area:
8071 pad="2*iw:2*ih:ow-iw:oh-ih"
8078 Generate one palette for a whole video stream.
8080 It accepts the following options:
8084 Set the maximum number of colors to quantize in the palette.
8085 Note: the palette will still contain 256 colors; the unused palette entries
8088 @item reserve_transparent
8089 Create a palette of 255 colors maximum and reserve the last one for
8090 transparency. Reserving the transparency color is useful for GIF optimization.
8091 If not set, the maximum of colors in the palette will be 256. You probably want
8092 to disable this option for a standalone image.
8096 Set statistics mode.
8098 It accepts the following values:
8101 Compute full frame histograms.
8103 Compute histograms only for the part that differs from previous frame. This
8104 might be relevant to give more importance to the moving part of your input if
8105 the background is static.
8108 Default value is @var{full}.
8111 The filter also exports the frame metadata @code{lavfi.color_quant_ratio}
8112 (@code{nb_color_in / nb_color_out}) which you can use to evaluate the degree of
8113 color quantization of the palette. This information is also visible at
8114 @var{info} logging level.
8116 @subsection Examples
8120 Generate a representative palette of a given video using @command{ffmpeg}:
8122 ffmpeg -i input.mkv -vf palettegen palette.png
8128 Use a palette to downsample an input video stream.
8130 The filter takes two inputs: one video stream and a palette. The palette must
8131 be a 256 pixels image.
8133 It accepts the following options:
8137 Select dithering mode. Available algorithms are:
8140 Ordered 8x8 bayer dithering (deterministic)
8142 Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
8143 Note: this dithering is sometimes considered "wrong" and is included as a
8145 @item floyd_steinberg
8146 Floyd and Steingberg dithering (error diffusion)
8148 Frankie Sierra dithering v2 (error diffusion)
8150 Frankie Sierra dithering v2 "Lite" (error diffusion)
8153 Default is @var{sierra2_4a}.
8156 When @var{bayer} dithering is selected, this option defines the scale of the
8157 pattern (how much the crosshatch pattern is visible). A low value means more
8158 visible pattern for less banding, and higher value means less visible pattern
8159 at the cost of more banding.
8161 The option must be an integer value in the range [0,5]. Default is @var{2}.
8164 If set, define the zone to process
8168 Only the changing rectangle will be reprocessed. This is similar to GIF
8169 cropping/offsetting compression mechanism. This option can be useful for speed
8170 if only a part of the image is changing, and has use cases such as limiting the
8171 scope of the error diffusal @option{dither} to the rectangle that bounds the
8172 moving scene (it leads to more deterministic output if the scene doesn't change
8173 much, and as a result less moving noise and better GIF compression).
8176 Default is @var{none}.
8179 @subsection Examples
8183 Use a palette (generated for example with @ref{palettegen}) to encode a GIF
8184 using @command{ffmpeg}:
8186 ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
8190 @section perspective
8192 Correct perspective of video not recorded perpendicular to the screen.
8194 A description of the accepted parameters follows.
8205 Set coordinates expression for top left, top right, bottom left and bottom right corners.
8206 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
8207 If the @code{sense} option is set to @code{source}, then the specified points will be sent
8208 to the corners of the destination. If the @code{sense} option is set to @code{destination},
8209 then the corners of the source will be sent to the specified coordinates.
8211 The expressions can use the following variables:
8216 the width and height of video frame.
8220 Set interpolation for perspective correction.
8222 It accepts the following values:
8228 Default value is @samp{linear}.
8231 Set interpretation of coordinate options.
8233 It accepts the following values:
8237 Send point in the source specified by the given coordinates to
8238 the corners of the destination.
8240 @item 1, destination
8242 Send the corners of the source to the point in the destination specified
8243 by the given coordinates.
8245 Default value is @samp{source}.
8251 Delay interlaced video by one field time so that the field order changes.
8253 The intended use is to fix PAL movies that have been captured with the
8254 opposite field order to the film-to-video transfer.
8256 A description of the accepted parameters follows.
8262 It accepts the following values:
8265 Capture field order top-first, transfer bottom-first.
8266 Filter will delay the bottom field.
8269 Capture field order bottom-first, transfer top-first.
8270 Filter will delay the top field.
8273 Capture and transfer with the same field order. This mode only exists
8274 for the documentation of the other options to refer to, but if you
8275 actually select it, the filter will faithfully do nothing.
8278 Capture field order determined automatically by field flags, transfer
8280 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
8281 basis using field flags. If no field information is available,
8282 then this works just like @samp{u}.
8285 Capture unknown or varying, transfer opposite.
8286 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
8287 analyzing the images and selecting the alternative that produces best
8288 match between the fields.
8291 Capture top-first, transfer unknown or varying.
8292 Filter selects among @samp{t} and @samp{p} using image analysis.
8295 Capture bottom-first, transfer unknown or varying.
8296 Filter selects among @samp{b} and @samp{p} using image analysis.
8299 Capture determined by field flags, transfer unknown or varying.
8300 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
8301 image analysis. If no field information is available, then this works just
8302 like @samp{U}. This is the default mode.
8305 Both capture and transfer unknown or varying.
8306 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
8310 @section pixdesctest
8312 Pixel format descriptor test filter, mainly useful for internal
8313 testing. The output video should be equal to the input video.
8317 format=monow, pixdesctest
8320 can be used to test the monowhite pixel format descriptor definition.
8324 Enable the specified chain of postprocessing subfilters using libpostproc. This
8325 library should be automatically selected with a GPL build (@code{--enable-gpl}).
8326 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
8327 Each subfilter and some options have a short and a long name that can be used
8328 interchangeably, i.e. dr/dering are the same.
8330 The filters accept the following options:
8334 Set postprocessing subfilters string.
8337 All subfilters share common options to determine their scope:
8341 Honor the quality commands for this subfilter.
8344 Do chrominance filtering, too (default).
8347 Do luminance filtering only (no chrominance).
8350 Do chrominance filtering only (no luminance).
8353 These options can be appended after the subfilter name, separated by a '|'.
8355 Available subfilters are:
8358 @item hb/hdeblock[|difference[|flatness]]
8359 Horizontal deblocking filter
8362 Difference factor where higher values mean more deblocking (default: @code{32}).
8364 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8367 @item vb/vdeblock[|difference[|flatness]]
8368 Vertical deblocking filter
8371 Difference factor where higher values mean more deblocking (default: @code{32}).
8373 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8376 @item ha/hadeblock[|difference[|flatness]]
8377 Accurate horizontal deblocking filter
8380 Difference factor where higher values mean more deblocking (default: @code{32}).
8382 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8385 @item va/vadeblock[|difference[|flatness]]
8386 Accurate vertical deblocking filter
8389 Difference factor where higher values mean more deblocking (default: @code{32}).
8391 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8395 The horizontal and vertical deblocking filters share the difference and
8396 flatness values so you cannot set different horizontal and vertical
8401 Experimental horizontal deblocking filter
8404 Experimental vertical deblocking filter
8409 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
8412 larger -> stronger filtering
8414 larger -> stronger filtering
8416 larger -> stronger filtering
8419 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
8422 Stretch luminance to @code{0-255}.
8425 @item lb/linblenddeint
8426 Linear blend deinterlacing filter that deinterlaces the given block by
8427 filtering all lines with a @code{(1 2 1)} filter.
8429 @item li/linipoldeint
8430 Linear interpolating deinterlacing filter that deinterlaces the given block by
8431 linearly interpolating every second line.
8433 @item ci/cubicipoldeint
8434 Cubic interpolating deinterlacing filter deinterlaces the given block by
8435 cubically interpolating every second line.
8437 @item md/mediandeint
8438 Median deinterlacing filter that deinterlaces the given block by applying a
8439 median filter to every second line.
8441 @item fd/ffmpegdeint
8442 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
8443 second line with a @code{(-1 4 2 4 -1)} filter.
8446 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
8447 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
8449 @item fq/forceQuant[|quantizer]
8450 Overrides the quantizer table from the input with the constant quantizer you
8458 Default pp filter combination (@code{hb|a,vb|a,dr|a})
8461 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
8464 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
8467 @subsection Examples
8471 Apply horizontal and vertical deblocking, deringing and automatic
8472 brightness/contrast:
8478 Apply default filters without brightness/contrast correction:
8484 Apply default filters and temporal denoiser:
8486 pp=default/tmpnoise|1|2|3
8490 Apply deblocking on luminance only, and switch vertical deblocking on or off
8491 automatically depending on available CPU time:
8498 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
8499 similar to spp = 6 with 7 point DCT, where only the center sample is
8502 The filter accepts the following options:
8506 Force a constant quantization parameter. It accepts an integer in range
8507 0 to 63. If not set, the filter will use the QP from the video stream
8511 Set thresholding mode. Available modes are:
8515 Set hard thresholding.
8517 Set soft thresholding (better de-ringing effect, but likely blurrier).
8519 Set medium thresholding (good results, default).
8525 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
8526 Ratio) between two input videos.
8528 This filter takes in input two input videos, the first input is
8529 considered the "main" source and is passed unchanged to the
8530 output. The second input is used as a "reference" video for computing
8533 Both video inputs must have the same resolution and pixel format for
8534 this filter to work correctly. Also it assumes that both inputs
8535 have the same number of frames, which are compared one by one.
8537 The obtained average PSNR is printed through the logging system.
8539 The filter stores the accumulated MSE (mean squared error) of each
8540 frame, and at the end of the processing it is averaged across all frames
8541 equally, and the following formula is applied to obtain the PSNR:
8544 PSNR = 10*log10(MAX^2/MSE)
8547 Where MAX is the average of the maximum values of each component of the
8550 The description of the accepted parameters follows.
8554 If specified the filter will use the named file to save the PSNR of
8555 each individual frame.
8558 The file printed if @var{stats_file} is selected, contains a sequence of
8559 key/value pairs of the form @var{key}:@var{value} for each compared
8562 A description of each shown parameter follows:
8566 sequential number of the input frame, starting from 1
8569 Mean Square Error pixel-by-pixel average difference of the compared
8570 frames, averaged over all the image components.
8572 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
8573 Mean Square Error pixel-by-pixel average difference of the compared
8574 frames for the component specified by the suffix.
8576 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
8577 Peak Signal to Noise ratio of the compared frames for the component
8578 specified by the suffix.
8583 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
8584 [main][ref] psnr="stats_file=stats.log" [out]
8587 On this example the input file being processed is compared with the
8588 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
8589 is stored in @file{stats.log}.
8594 Pulldown reversal (inverse telecine) filter, capable of handling mixed
8595 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
8598 The pullup filter is designed to take advantage of future context in making
8599 its decisions. This filter is stateless in the sense that it does not lock
8600 onto a pattern to follow, but it instead looks forward to the following
8601 fields in order to identify matches and rebuild progressive frames.
8603 To produce content with an even framerate, insert the fps filter after
8604 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
8605 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
8607 The filter accepts the following options:
8614 These options set the amount of "junk" to ignore at the left, right, top, and
8615 bottom of the image, respectively. Left and right are in units of 8 pixels,
8616 while top and bottom are in units of 2 lines.
8617 The default is 8 pixels on each side.
8620 Set the strict breaks. Setting this option to 1 will reduce the chances of
8621 filter generating an occasional mismatched frame, but it may also cause an
8622 excessive number of frames to be dropped during high motion sequences.
8623 Conversely, setting it to -1 will make filter match fields more easily.
8624 This may help processing of video where there is slight blurring between
8625 the fields, but may also cause there to be interlaced frames in the output.
8626 Default value is @code{0}.
8629 Set the metric plane to use. It accepts the following values:
8635 Use chroma blue plane.
8638 Use chroma red plane.
8641 This option may be set to use chroma plane instead of the default luma plane
8642 for doing filter's computations. This may improve accuracy on very clean
8643 source material, but more likely will decrease accuracy, especially if there
8644 is chroma noise (rainbow effect) or any grayscale video.
8645 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
8646 load and make pullup usable in realtime on slow machines.
8649 For best results (without duplicated frames in the output file) it is
8650 necessary to change the output frame rate. For example, to inverse
8651 telecine NTSC input:
8653 ffmpeg -i input -vf pullup -r 24000/1001 ...
8658 Change video quantization parameters (QP).
8660 The filter accepts the following option:
8664 Set expression for quantization parameter.
8667 The expression is evaluated through the eval API and can contain, among others,
8668 the following constants:
8672 1 if index is not 129, 0 otherwise.
8675 Sequentional index starting from -129 to 128.
8678 @subsection Examples
8690 Flush video frames from internal cache of frames into a random order.
8691 No frame is discarded.
8692 Inspired by @ref{frei0r} nervous filter.
8696 Set size in number of frames of internal cache, in range from @code{2} to
8697 @code{512}. Default is @code{30}.
8700 Set seed for random number generator, must be an integer included between
8701 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
8702 less than @code{0}, the filter will try to use a good random seed on a
8706 @section removegrain
8708 The removegrain filter is a spatial denoiser for progressive video.
8712 Set mode for the first plane.
8715 Set mode for the second plane.
8718 Set mode for the third plane.
8721 Set mode for the fourth plane.
8724 Range of mode is from 0 to 24. Description of each mode follows:
8728 Leave input plane unchanged. Default.
8731 Clips the pixel with the minimum and maximum of the 8 neighbour pixels.
8734 Clips the pixel with the second minimum and maximum of the 8 neighbour pixels.
8737 Clips the pixel with the third minimum and maximum of the 8 neighbour pixels.
8740 Clips the pixel with the fourth minimum and maximum of the 8 neighbour pixels.
8741 This is equivalent to a median filter.
8744 Line-sensitive clipping giving the minimal change.
8747 Line-sensitive clipping, intermediate.
8750 Line-sensitive clipping, intermediate.
8753 Line-sensitive clipping, intermediate.
8756 Line-sensitive clipping on a line where the neighbours pixels are the closest.
8759 Replaces the target pixel with the closest neighbour.
8762 [1 2 1] horizontal and vertical kernel blur.
8768 Bob mode, interpolates top field from the line where the neighbours
8769 pixels are the closest.
8772 Bob mode, interpolates bottom field from the line where the neighbours
8773 pixels are the closest.
8776 Bob mode, interpolates top field. Same as 13 but with a more complicated
8777 interpolation formula.
8780 Bob mode, interpolates bottom field. Same as 14 but with a more complicated
8781 interpolation formula.
8784 Clips the pixel with the minimum and maximum of respectively the maximum and
8785 minimum of each pair of opposite neighbour pixels.
8788 Line-sensitive clipping using opposite neighbours whose greatest distance from
8789 the current pixel is minimal.
8792 Replaces the pixel with the average of its 8 neighbours.
8795 Averages the 9 pixels ([1 1 1] horizontal and vertical blur).
8798 Clips pixels using the averages of opposite neighbour.
8801 Same as mode 21 but simpler and faster.
8804 Small edge and halo removal, but reputed useless.
8812 Suppress a TV station logo, using an image file to determine which
8813 pixels comprise the logo. It works by filling in the pixels that
8814 comprise the logo with neighboring pixels.
8816 The filter accepts the following options:
8820 Set the filter bitmap file, which can be any image format supported by
8821 libavformat. The width and height of the image file must match those of the
8822 video stream being processed.
8825 Pixels in the provided bitmap image with a value of zero are not
8826 considered part of the logo, non-zero pixels are considered part of
8827 the logo. If you use white (255) for the logo and black (0) for the
8828 rest, you will be safe. For making the filter bitmap, it is
8829 recommended to take a screen capture of a black frame with the logo
8830 visible, and then using a threshold filter followed by the erode
8831 filter once or twice.
8833 If needed, little splotches can be fixed manually. Remember that if
8834 logo pixels are not covered, the filter quality will be much
8835 reduced. Marking too many pixels as part of the logo does not hurt as
8836 much, but it will increase the amount of blurring needed to cover over
8837 the image and will destroy more information than necessary, and extra
8838 pixels will slow things down on a large logo.
8840 @section repeatfields
8842 This filter uses the repeat_field flag from the Video ES headers and hard repeats
8843 fields based on its value.
8845 @section reverse, areverse
8849 Warning: This filter requires memory to buffer the entire clip, so trimming
8852 @subsection Examples
8856 Take the first 5 seconds of a clip, and reverse it.
8864 Rotate video by an arbitrary angle expressed in radians.
8866 The filter accepts the following options:
8868 A description of the optional parameters follows.
8871 Set an expression for the angle by which to rotate the input video
8872 clockwise, expressed as a number of radians. A negative value will
8873 result in a counter-clockwise rotation. By default it is set to "0".
8875 This expression is evaluated for each frame.
8878 Set the output width expression, default value is "iw".
8879 This expression is evaluated just once during configuration.
8882 Set the output height expression, default value is "ih".
8883 This expression is evaluated just once during configuration.
8886 Enable bilinear interpolation if set to 1, a value of 0 disables
8887 it. Default value is 1.
8890 Set the color used to fill the output area not covered by the rotated
8891 image. For the general syntax of this option, check the "Color" section in the
8892 ffmpeg-utils manual. If the special value "none" is selected then no
8893 background is printed (useful for example if the background is never shown).
8895 Default value is "black".
8898 The expressions for the angle and the output size can contain the
8899 following constants and functions:
8903 sequential number of the input frame, starting from 0. It is always NAN
8904 before the first frame is filtered.
8907 time in seconds of the input frame, it is set to 0 when the filter is
8908 configured. It is always NAN before the first frame is filtered.
8912 horizontal and vertical chroma subsample values. For example for the
8913 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
8917 the input video width and height
8921 the output width and height, that is the size of the padded area as
8922 specified by the @var{width} and @var{height} expressions
8926 the minimal width/height required for completely containing the input
8927 video rotated by @var{a} radians.
8929 These are only available when computing the @option{out_w} and
8930 @option{out_h} expressions.
8933 @subsection Examples
8937 Rotate the input by PI/6 radians clockwise:
8943 Rotate the input by PI/6 radians counter-clockwise:
8949 Rotate the input by 45 degrees clockwise:
8955 Apply a constant rotation with period T, starting from an angle of PI/3:
8957 rotate=PI/3+2*PI*t/T
8961 Make the input video rotation oscillating with a period of T
8962 seconds and an amplitude of A radians:
8964 rotate=A*sin(2*PI/T*t)
8968 Rotate the video, output size is chosen so that the whole rotating
8969 input video is always completely contained in the output:
8971 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
8975 Rotate the video, reduce the output size so that no background is ever
8978 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
8982 @subsection Commands
8984 The filter supports the following commands:
8988 Set the angle expression.
8989 The command accepts the same syntax of the corresponding option.
8991 If the specified expression is not valid, it is kept at its current
8997 Apply Shape Adaptive Blur.
8999 The filter accepts the following options:
9002 @item luma_radius, lr
9003 Set luma blur filter strength, must be a value in range 0.1-4.0, default
9004 value is 1.0. A greater value will result in a more blurred image, and
9005 in slower processing.
9007 @item luma_pre_filter_radius, lpfr
9008 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
9011 @item luma_strength, ls
9012 Set luma maximum difference between pixels to still be considered, must
9013 be a value in the 0.1-100.0 range, default value is 1.0.
9015 @item chroma_radius, cr
9016 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
9017 greater value will result in a more blurred image, and in slower
9020 @item chroma_pre_filter_radius, cpfr
9021 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
9023 @item chroma_strength, cs
9024 Set chroma maximum difference between pixels to still be considered,
9025 must be a value in the 0.1-100.0 range.
9028 Each chroma option value, if not explicitly specified, is set to the
9029 corresponding luma option value.
9034 Scale (resize) the input video, using the libswscale library.
9036 The scale filter forces the output display aspect ratio to be the same
9037 of the input, by changing the output sample aspect ratio.
9039 If the input image format is different from the format requested by
9040 the next filter, the scale filter will convert the input to the
9044 The filter accepts the following options, or any of the options
9045 supported by the libswscale scaler.
9047 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
9048 the complete list of scaler options.
9053 Set the output video dimension expression. Default value is the input
9056 If the value is 0, the input width is used for the output.
9058 If one of the values is -1, the scale filter will use a value that
9059 maintains the aspect ratio of the input image, calculated from the
9060 other specified dimension. If both of them are -1, the input size is
9063 If one of the values is -n with n > 1, the scale filter will also use a value
9064 that maintains the aspect ratio of the input image, calculated from the other
9065 specified dimension. After that it will, however, make sure that the calculated
9066 dimension is divisible by n and adjust the value if necessary.
9068 See below for the list of accepted constants for use in the dimension
9072 Set the interlacing mode. It accepts the following values:
9076 Force interlaced aware scaling.
9079 Do not apply interlaced scaling.
9082 Select interlaced aware scaling depending on whether the source frames
9083 are flagged as interlaced or not.
9086 Default value is @samp{0}.
9089 Set libswscale scaling flags. See
9090 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
9091 complete list of values. If not explicitly specified the filter applies
9095 Set the video size. For the syntax of this option, check the
9096 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
9098 @item in_color_matrix
9099 @item out_color_matrix
9100 Set in/output YCbCr color space type.
9102 This allows the autodetected value to be overridden as well as allows forcing
9103 a specific value used for the output and encoder.
9105 If not specified, the color space type depends on the pixel format.
9111 Choose automatically.
9114 Format conforming to International Telecommunication Union (ITU)
9115 Recommendation BT.709.
9118 Set color space conforming to the United States Federal Communications
9119 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
9122 Set color space conforming to:
9126 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
9129 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
9132 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
9137 Set color space conforming to SMPTE ST 240:1999.
9142 Set in/output YCbCr sample range.
9144 This allows the autodetected value to be overridden as well as allows forcing
9145 a specific value used for the output and encoder. If not specified, the
9146 range depends on the pixel format. Possible values:
9150 Choose automatically.
9153 Set full range (0-255 in case of 8-bit luma).
9156 Set "MPEG" range (16-235 in case of 8-bit luma).
9159 @item force_original_aspect_ratio
9160 Enable decreasing or increasing output video width or height if necessary to
9161 keep the original aspect ratio. Possible values:
9165 Scale the video as specified and disable this feature.
9168 The output video dimensions will automatically be decreased if needed.
9171 The output video dimensions will automatically be increased if needed.
9175 One useful instance of this option is that when you know a specific device's
9176 maximum allowed resolution, you can use this to limit the output video to
9177 that, while retaining the aspect ratio. For example, device A allows
9178 1280x720 playback, and your video is 1920x800. Using this option (set it to
9179 decrease) and specifying 1280x720 to the command line makes the output
9182 Please note that this is a different thing than specifying -1 for @option{w}
9183 or @option{h}, you still need to specify the output resolution for this option
9188 The values of the @option{w} and @option{h} options are expressions
9189 containing the following constants:
9194 The input width and height
9198 These are the same as @var{in_w} and @var{in_h}.
9202 The output (scaled) width and height
9206 These are the same as @var{out_w} and @var{out_h}
9209 The same as @var{iw} / @var{ih}
9212 input sample aspect ratio
9215 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
9219 horizontal and vertical input chroma subsample values. For example for the
9220 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9224 horizontal and vertical output chroma subsample values. For example for the
9225 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9228 @subsection Examples
9232 Scale the input video to a size of 200x100
9237 This is equivalent to:
9248 Specify a size abbreviation for the output size:
9253 which can also be written as:
9259 Scale the input to 2x:
9265 The above is the same as:
9271 Scale the input to 2x with forced interlaced scaling:
9273 scale=2*iw:2*ih:interl=1
9277 Scale the input to half size:
9283 Increase the width, and set the height to the same size:
9296 Increase the height, and set the width to 3/2 of the height:
9298 scale=w=3/2*oh:h=3/5*ih
9302 Increase the size, making the size a multiple of the chroma
9305 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
9309 Increase the width to a maximum of 500 pixels,
9310 keeping the same aspect ratio as the input:
9312 scale=w='min(500\, iw*3/2):h=-1'
9316 @subsection Commands
9318 This filter supports the following commands:
9322 Set the output video dimension expression.
9323 The command accepts the same syntax of the corresponding option.
9325 If the specified expression is not valid, it is kept at its current
9331 Scale (resize) the input video, based on a reference video.
9333 See the scale filter for available options, scale2ref supports the same but
9334 uses the reference video instead of the main input as basis.
9336 @subsection Examples
9340 Scale a subtitle stream to match the main video in size before overlaying
9342 'scale2ref[b][a];[a][b]overlay'
9346 @section separatefields
9348 The @code{separatefields} takes a frame-based video input and splits
9349 each frame into its components fields, producing a new half height clip
9350 with twice the frame rate and twice the frame count.
9352 This filter use field-dominance information in frame to decide which
9353 of each pair of fields to place first in the output.
9354 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
9356 @section setdar, setsar
9358 The @code{setdar} filter sets the Display Aspect Ratio for the filter
9361 This is done by changing the specified Sample (aka Pixel) Aspect
9362 Ratio, according to the following equation:
9364 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
9367 Keep in mind that the @code{setdar} filter does not modify the pixel
9368 dimensions of the video frame. Also, the display aspect ratio set by
9369 this filter may be changed by later filters in the filterchain,
9370 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
9373 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
9374 the filter output video.
9376 Note that as a consequence of the application of this filter, the
9377 output display aspect ratio will change according to the equation
9380 Keep in mind that the sample aspect ratio set by the @code{setsar}
9381 filter may be changed by later filters in the filterchain, e.g. if
9382 another "setsar" or a "setdar" filter is applied.
9384 It accepts the following parameters:
9387 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
9388 Set the aspect ratio used by the filter.
9390 The parameter can be a floating point number string, an expression, or
9391 a string of the form @var{num}:@var{den}, where @var{num} and
9392 @var{den} are the numerator and denominator of the aspect ratio. If
9393 the parameter is not specified, it is assumed the value "0".
9394 In case the form "@var{num}:@var{den}" is used, the @code{:} character
9398 Set the maximum integer value to use for expressing numerator and
9399 denominator when reducing the expressed aspect ratio to a rational.
9400 Default value is @code{100}.
9404 The parameter @var{sar} is an expression containing
9405 the following constants:
9409 These are approximated values for the mathematical constants e
9410 (Euler's number), pi (Greek pi), and phi (the golden ratio).
9413 The input width and height.
9416 These are the same as @var{w} / @var{h}.
9419 The input sample aspect ratio.
9422 The input display aspect ratio. It is the same as
9423 (@var{w} / @var{h}) * @var{sar}.
9426 Horizontal and vertical chroma subsample values. For example, for the
9427 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9430 @subsection Examples
9435 To change the display aspect ratio to 16:9, specify one of the following:
9443 To change the sample aspect ratio to 10:11, specify:
9449 To set a display aspect ratio of 16:9, and specify a maximum integer value of
9450 1000 in the aspect ratio reduction, use the command:
9452 setdar=ratio=16/9:max=1000
9460 Force field for the output video frame.
9462 The @code{setfield} filter marks the interlace type field for the
9463 output frames. It does not change the input frame, but only sets the
9464 corresponding property, which affects how the frame is treated by
9465 following filters (e.g. @code{fieldorder} or @code{yadif}).
9467 The filter accepts the following options:
9472 Available values are:
9476 Keep the same field property.
9479 Mark the frame as bottom-field-first.
9482 Mark the frame as top-field-first.
9485 Mark the frame as progressive.
9491 Show a line containing various information for each input video frame.
9492 The input video is not modified.
9494 The shown line contains a sequence of key/value pairs of the form
9495 @var{key}:@var{value}.
9497 The following values are shown in the output:
9501 The (sequential) number of the input frame, starting from 0.
9504 The Presentation TimeStamp of the input frame, expressed as a number of
9505 time base units. The time base unit depends on the filter input pad.
9508 The Presentation TimeStamp of the input frame, expressed as a number of
9512 The position of the frame in the input stream, or -1 if this information is
9513 unavailable and/or meaningless (for example in case of synthetic video).
9516 The pixel format name.
9519 The sample aspect ratio of the input frame, expressed in the form
9520 @var{num}/@var{den}.
9523 The size of the input frame. For the syntax of this option, check the
9524 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
9527 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
9528 for bottom field first).
9531 This is 1 if the frame is a key frame, 0 otherwise.
9534 The picture type of the input frame ("I" for an I-frame, "P" for a
9535 P-frame, "B" for a B-frame, or "?" for an unknown type).
9536 Also refer to the documentation of the @code{AVPictureType} enum and of
9537 the @code{av_get_picture_type_char} function defined in
9538 @file{libavutil/avutil.h}.
9541 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
9543 @item plane_checksum
9544 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
9545 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
9548 @section showpalette
9550 Displays the 256 colors palette of each frame. This filter is only relevant for
9551 @var{pal8} pixel format frames.
9553 It accepts the following option:
9557 Set the size of the box used to represent one palette color entry. Default is
9558 @code{30} (for a @code{30x30} pixel box).
9561 @section shuffleplanes
9563 Reorder and/or duplicate video planes.
9565 It accepts the following parameters:
9570 The index of the input plane to be used as the first output plane.
9573 The index of the input plane to be used as the second output plane.
9576 The index of the input plane to be used as the third output plane.
9579 The index of the input plane to be used as the fourth output plane.
9583 The first plane has the index 0. The default is to keep the input unchanged.
9585 Swap the second and third planes of the input:
9587 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
9590 @anchor{signalstats}
9591 @section signalstats
9592 Evaluate various visual metrics that assist in determining issues associated
9593 with the digitization of analog video media.
9595 By default the filter will log these metadata values:
9599 Display the minimal Y value contained within the input frame. Expressed in
9603 Display the Y value at the 10% percentile within the input frame. Expressed in
9607 Display the average Y value within the input frame. Expressed in range of
9611 Display the Y value at the 90% percentile within the input frame. Expressed in
9615 Display the maximum Y value contained within the input frame. Expressed in
9619 Display the minimal U value contained within the input frame. Expressed in
9623 Display the U value at the 10% percentile within the input frame. Expressed in
9627 Display the average U value within the input frame. Expressed in range of
9631 Display the U value at the 90% percentile within the input frame. Expressed in
9635 Display the maximum U value contained within the input frame. Expressed in
9639 Display the minimal V value contained within the input frame. Expressed in
9643 Display the V value at the 10% percentile within the input frame. Expressed in
9647 Display the average V value within the input frame. Expressed in range of
9651 Display the V value at the 90% percentile within the input frame. Expressed in
9655 Display the maximum V value contained within the input frame. Expressed in
9659 Display the minimal saturation value contained within the input frame.
9660 Expressed in range of [0-~181.02].
9663 Display the saturation value at the 10% percentile within the input frame.
9664 Expressed in range of [0-~181.02].
9667 Display the average saturation value within the input frame. Expressed in range
9671 Display the saturation value at the 90% percentile within the input frame.
9672 Expressed in range of [0-~181.02].
9675 Display the maximum saturation value contained within the input frame.
9676 Expressed in range of [0-~181.02].
9679 Display the median value for hue within the input frame. Expressed in range of
9683 Display the average value for hue within the input frame. Expressed in range of
9687 Display the average of sample value difference between all values of the Y
9688 plane in the current frame and corresponding values of the previous input frame.
9689 Expressed in range of [0-255].
9692 Display the average of sample value difference between all values of the U
9693 plane in the current frame and corresponding values of the previous input frame.
9694 Expressed in range of [0-255].
9697 Display the average of sample value difference between all values of the V
9698 plane in the current frame and corresponding values of the previous input frame.
9699 Expressed in range of [0-255].
9702 The filter accepts the following options:
9708 @option{stat} specify an additional form of image analysis.
9709 @option{out} output video with the specified type of pixel highlighted.
9711 Both options accept the following values:
9715 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
9716 unlike the neighboring pixels of the same field. Examples of temporal outliers
9717 include the results of video dropouts, head clogs, or tape tracking issues.
9720 Identify @var{vertical line repetition}. Vertical line repetition includes
9721 similar rows of pixels within a frame. In born-digital video vertical line
9722 repetition is common, but this pattern is uncommon in video digitized from an
9723 analog source. When it occurs in video that results from the digitization of an
9724 analog source it can indicate concealment from a dropout compensator.
9727 Identify pixels that fall outside of legal broadcast range.
9731 Set the highlight color for the @option{out} option. The default color is
9735 @subsection Examples
9739 Output data of various video metrics:
9741 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
9745 Output specific data about the minimum and maximum values of the Y plane per frame:
9747 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
9751 Playback video while highlighting pixels that are outside of broadcast range in red.
9753 ffplay example.mov -vf signalstats="out=brng:color=red"
9757 Playback video with signalstats metadata drawn over the frame.
9759 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
9762 The contents of signalstat_drawtext.txt used in the command are:
9765 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
9766 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
9767 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
9768 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
9776 Blur the input video without impacting the outlines.
9778 It accepts the following options:
9781 @item luma_radius, lr
9782 Set the luma radius. The option value must be a float number in
9783 the range [0.1,5.0] that specifies the variance of the gaussian filter
9784 used to blur the image (slower if larger). Default value is 1.0.
9786 @item luma_strength, ls
9787 Set the luma strength. The option value must be a float number
9788 in the range [-1.0,1.0] that configures the blurring. A value included
9789 in [0.0,1.0] will blur the image whereas a value included in
9790 [-1.0,0.0] will sharpen the image. Default value is 1.0.
9792 @item luma_threshold, lt
9793 Set the luma threshold used as a coefficient to determine
9794 whether a pixel should be blurred or not. The option value must be an
9795 integer in the range [-30,30]. A value of 0 will filter all the image,
9796 a value included in [0,30] will filter flat areas and a value included
9797 in [-30,0] will filter edges. Default value is 0.
9799 @item chroma_radius, cr
9800 Set the chroma radius. The option value must be a float number in
9801 the range [0.1,5.0] that specifies the variance of the gaussian filter
9802 used to blur the image (slower if larger). Default value is 1.0.
9804 @item chroma_strength, cs
9805 Set the chroma strength. The option value must be a float number
9806 in the range [-1.0,1.0] that configures the blurring. A value included
9807 in [0.0,1.0] will blur the image whereas a value included in
9808 [-1.0,0.0] will sharpen the image. Default value is 1.0.
9810 @item chroma_threshold, ct
9811 Set the chroma threshold used as a coefficient to determine
9812 whether a pixel should be blurred or not. The option value must be an
9813 integer in the range [-30,30]. A value of 0 will filter all the image,
9814 a value included in [0,30] will filter flat areas and a value included
9815 in [-30,0] will filter edges. Default value is 0.
9818 If a chroma option is not explicitly set, the corresponding luma value
9823 Obtain the SSIM (Structural SImilarity Metric) between two input videos.
9825 This filter takes in input two input videos, the first input is
9826 considered the "main" source and is passed unchanged to the
9827 output. The second input is used as a "reference" video for computing
9830 Both video inputs must have the same resolution and pixel format for
9831 this filter to work correctly. Also it assumes that both inputs
9832 have the same number of frames, which are compared one by one.
9834 The filter stores the calculated SSIM of each frame.
9836 The description of the accepted parameters follows.
9840 If specified the filter will use the named file to save the SSIM of
9841 each individual frame.
9844 The file printed if @var{stats_file} is selected, contains a sequence of
9845 key/value pairs of the form @var{key}:@var{value} for each compared
9848 A description of each shown parameter follows:
9852 sequential number of the input frame, starting from 1
9854 @item Y, U, V, R, G, B
9855 SSIM of the compared frames for the component specified by the suffix.
9858 SSIM of the compared frames for the whole frame.
9861 Same as above but in dB representation.
9866 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
9867 [main][ref] ssim="stats_file=stats.log" [out]
9870 On this example the input file being processed is compared with the
9871 reference file @file{ref_movie.mpg}. The SSIM of each individual frame
9872 is stored in @file{stats.log}.
9874 Another example with both psnr and ssim at same time:
9876 ffmpeg -i main.mpg -i ref.mpg -lavfi "ssim;[0:v][1:v]psnr" -f null -
9881 Convert between different stereoscopic image formats.
9883 The filters accept the following options:
9887 Set stereoscopic image format of input.
9889 Available values for input image formats are:
9892 side by side parallel (left eye left, right eye right)
9895 side by side crosseye (right eye left, left eye right)
9898 side by side parallel with half width resolution
9899 (left eye left, right eye right)
9902 side by side crosseye with half width resolution
9903 (right eye left, left eye right)
9906 above-below (left eye above, right eye below)
9909 above-below (right eye above, left eye below)
9912 above-below with half height resolution
9913 (left eye above, right eye below)
9916 above-below with half height resolution
9917 (right eye above, left eye below)
9920 alternating frames (left eye first, right eye second)
9923 alternating frames (right eye first, left eye second)
9926 interleaved rows (left eye has top row, right eye starts on next row)
9929 interleaved rows (right eye has top row, left eye starts on next row)
9931 Default value is @samp{sbsl}.
9935 Set stereoscopic image format of output.
9937 Available values for output image formats are all the input formats as well as:
9940 anaglyph red/blue gray
9941 (red filter on left eye, blue filter on right eye)
9944 anaglyph red/green gray
9945 (red filter on left eye, green filter on right eye)
9948 anaglyph red/cyan gray
9949 (red filter on left eye, cyan filter on right eye)
9952 anaglyph red/cyan half colored
9953 (red filter on left eye, cyan filter on right eye)
9956 anaglyph red/cyan color
9957 (red filter on left eye, cyan filter on right eye)
9960 anaglyph red/cyan color optimized with the least squares projection of dubois
9961 (red filter on left eye, cyan filter on right eye)
9964 anaglyph green/magenta gray
9965 (green filter on left eye, magenta filter on right eye)
9968 anaglyph green/magenta half colored
9969 (green filter on left eye, magenta filter on right eye)
9972 anaglyph green/magenta colored
9973 (green filter on left eye, magenta filter on right eye)
9976 anaglyph green/magenta color optimized with the least squares projection of dubois
9977 (green filter on left eye, magenta filter on right eye)
9980 anaglyph yellow/blue gray
9981 (yellow filter on left eye, blue filter on right eye)
9984 anaglyph yellow/blue half colored
9985 (yellow filter on left eye, blue filter on right eye)
9988 anaglyph yellow/blue colored
9989 (yellow filter on left eye, blue filter on right eye)
9992 anaglyph yellow/blue color optimized with the least squares projection of dubois
9993 (yellow filter on left eye, blue filter on right eye)
9996 mono output (left eye only)
9999 mono output (right eye only)
10002 checkerboard, left eye first
10005 checkerboard, right eye first
10008 interleaved columns, left eye first
10011 interleaved columns, right eye first
10014 Default value is @samp{arcd}.
10017 @subsection Examples
10021 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
10027 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
10036 Apply a simple postprocessing filter that compresses and decompresses the image
10037 at several (or - in the case of @option{quality} level @code{6} - all) shifts
10038 and average the results.
10040 The filter accepts the following options:
10044 Set quality. This option defines the number of levels for averaging. It accepts
10045 an integer in the range 0-6. If set to @code{0}, the filter will have no
10046 effect. A value of @code{6} means the higher quality. For each increment of
10047 that value the speed drops by a factor of approximately 2. Default value is
10051 Force a constant quantization parameter. If not set, the filter will use the QP
10052 from the video stream (if available).
10055 Set thresholding mode. Available modes are:
10059 Set hard thresholding (default).
10061 Set soft thresholding (better de-ringing effect, but likely blurrier).
10064 @item use_bframe_qp
10065 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
10066 option may cause flicker since the B-Frames have often larger QP. Default is
10067 @code{0} (not enabled).
10073 Draw subtitles on top of input video using the libass library.
10075 To enable compilation of this filter you need to configure FFmpeg with
10076 @code{--enable-libass}. This filter also requires a build with libavcodec and
10077 libavformat to convert the passed subtitles file to ASS (Advanced Substation
10078 Alpha) subtitles format.
10080 The filter accepts the following options:
10084 Set the filename of the subtitle file to read. It must be specified.
10086 @item original_size
10087 Specify the size of the original video, the video for which the ASS file
10088 was composed. For the syntax of this option, check the
10089 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10090 Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
10091 correctly scale the fonts if the aspect ratio has been changed.
10094 Set a directory path containing fonts that can be used by the filter.
10095 These fonts will be used in addition to whatever the font provider uses.
10098 Set subtitles input character encoding. @code{subtitles} filter only. Only
10099 useful if not UTF-8.
10101 @item stream_index, si
10102 Set subtitles stream index. @code{subtitles} filter only.
10105 Override default style or script info parameters of the subtitles. It accepts a
10106 string containing ASS style format @code{KEY=VALUE} couples separated by ",".
10109 If the first key is not specified, it is assumed that the first value
10110 specifies the @option{filename}.
10112 For example, to render the file @file{sub.srt} on top of the input
10113 video, use the command:
10118 which is equivalent to:
10120 subtitles=filename=sub.srt
10123 To render the default subtitles stream from file @file{video.mkv}, use:
10125 subtitles=video.mkv
10128 To render the second subtitles stream from that file, use:
10130 subtitles=video.mkv:si=1
10133 To make the subtitles stream from @file{sub.srt} appear in transparent green
10134 @code{DejaVu Serif}, use:
10136 subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'
10139 @section super2xsai
10141 Scale the input by 2x and smooth using the Super2xSaI (Scale and
10142 Interpolate) pixel art scaling algorithm.
10144 Useful for enlarging pixel art images without reducing sharpness.
10151 Apply telecine process to the video.
10153 This filter accepts the following options:
10162 The default value is @code{top}.
10166 A string of numbers representing the pulldown pattern you wish to apply.
10167 The default value is @code{23}.
10171 Some typical patterns:
10176 24p: 2332 (preferred)
10183 24p: 222222222223 ("Euro pulldown")
10189 Select the most representative frame in a given sequence of consecutive frames.
10191 The filter accepts the following options:
10195 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
10196 will pick one of them, and then handle the next batch of @var{n} frames until
10197 the end. Default is @code{100}.
10200 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
10201 value will result in a higher memory usage, so a high value is not recommended.
10203 @subsection Examples
10207 Extract one picture each 50 frames:
10213 Complete example of a thumbnail creation with @command{ffmpeg}:
10215 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
10221 Tile several successive frames together.
10223 The filter accepts the following options:
10228 Set the grid size (i.e. the number of lines and columns). For the syntax of
10229 this option, check the
10230 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10233 Set the maximum number of frames to render in the given area. It must be less
10234 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
10235 the area will be used.
10238 Set the outer border margin in pixels.
10241 Set the inner border thickness (i.e. the number of pixels between frames). For
10242 more advanced padding options (such as having different values for the edges),
10243 refer to the pad video filter.
10246 Specify the color of the unused area. For the syntax of this option, check the
10247 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
10251 @subsection Examples
10255 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
10257 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
10259 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
10260 duplicating each output frame to accommodate the originally detected frame
10264 Display @code{5} pictures in an area of @code{3x2} frames,
10265 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
10266 mixed flat and named options:
10268 tile=3x2:nb_frames=5:padding=7:margin=2
10272 @section tinterlace
10274 Perform various types of temporal field interlacing.
10276 Frames are counted starting from 1, so the first input frame is
10279 The filter accepts the following options:
10284 Specify the mode of the interlacing. This option can also be specified
10285 as a value alone. See below for a list of values for this option.
10287 Available values are:
10291 Move odd frames into the upper field, even into the lower field,
10292 generating a double height frame at half frame rate.
10296 Frame 1 Frame 2 Frame 3 Frame 4
10298 11111 22222 33333 44444
10299 11111 22222 33333 44444
10300 11111 22222 33333 44444
10301 11111 22222 33333 44444
10315 Only output even frames, odd frames are dropped, generating a frame with
10316 unchanged height at half frame rate.
10321 Frame 1 Frame 2 Frame 3 Frame 4
10323 11111 22222 33333 44444
10324 11111 22222 33333 44444
10325 11111 22222 33333 44444
10326 11111 22222 33333 44444
10336 Only output odd frames, even frames are dropped, generating a frame with
10337 unchanged height at half frame rate.
10342 Frame 1 Frame 2 Frame 3 Frame 4
10344 11111 22222 33333 44444
10345 11111 22222 33333 44444
10346 11111 22222 33333 44444
10347 11111 22222 33333 44444
10357 Expand each frame to full height, but pad alternate lines with black,
10358 generating a frame with double height at the same input frame rate.
10363 Frame 1 Frame 2 Frame 3 Frame 4
10365 11111 22222 33333 44444
10366 11111 22222 33333 44444
10367 11111 22222 33333 44444
10368 11111 22222 33333 44444
10371 11111 ..... 33333 .....
10372 ..... 22222 ..... 44444
10373 11111 ..... 33333 .....
10374 ..... 22222 ..... 44444
10375 11111 ..... 33333 .....
10376 ..... 22222 ..... 44444
10377 11111 ..... 33333 .....
10378 ..... 22222 ..... 44444
10382 @item interleave_top, 4
10383 Interleave the upper field from odd frames with the lower field from
10384 even frames, generating a frame with unchanged height at half frame rate.
10389 Frame 1 Frame 2 Frame 3 Frame 4
10391 11111<- 22222 33333<- 44444
10392 11111 22222<- 33333 44444<-
10393 11111<- 22222 33333<- 44444
10394 11111 22222<- 33333 44444<-
10404 @item interleave_bottom, 5
10405 Interleave the lower field from odd frames with the upper field from
10406 even frames, generating a frame with unchanged height at half frame rate.
10411 Frame 1 Frame 2 Frame 3 Frame 4
10413 11111 22222<- 33333 44444<-
10414 11111<- 22222 33333<- 44444
10415 11111 22222<- 33333 44444<-
10416 11111<- 22222 33333<- 44444
10426 @item interlacex2, 6
10427 Double frame rate with unchanged height. Frames are inserted each
10428 containing the second temporal field from the previous input frame and
10429 the first temporal field from the next input frame. This mode relies on
10430 the top_field_first flag. Useful for interlaced video displays with no
10431 field synchronisation.
10436 Frame 1 Frame 2 Frame 3 Frame 4
10438 11111 22222 33333 44444
10439 11111 22222 33333 44444
10440 11111 22222 33333 44444
10441 11111 22222 33333 44444
10444 11111 22222 22222 33333 33333 44444 44444
10445 11111 11111 22222 22222 33333 33333 44444
10446 11111 22222 22222 33333 33333 44444 44444
10447 11111 11111 22222 22222 33333 33333 44444
10453 Numeric values are deprecated but are accepted for backward
10454 compatibility reasons.
10456 Default mode is @code{merge}.
10459 Specify flags influencing the filter process.
10461 Available value for @var{flags} is:
10464 @item low_pass_filter, vlfp
10465 Enable vertical low-pass filtering in the filter.
10466 Vertical low-pass filtering is required when creating an interlaced
10467 destination from a progressive source which contains high-frequency
10468 vertical detail. Filtering will reduce interlace 'twitter' and Moire
10471 Vertical low-pass filtering can only be enabled for @option{mode}
10472 @var{interleave_top} and @var{interleave_bottom}.
10479 Transpose rows with columns in the input video and optionally flip it.
10481 It accepts the following parameters:
10486 Specify the transposition direction.
10488 Can assume the following values:
10490 @item 0, 4, cclock_flip
10491 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
10499 Rotate by 90 degrees clockwise, that is:
10507 Rotate by 90 degrees counterclockwise, that is:
10514 @item 3, 7, clock_flip
10515 Rotate by 90 degrees clockwise and vertically flip, that is:
10523 For values between 4-7, the transposition is only done if the input
10524 video geometry is portrait and not landscape. These values are
10525 deprecated, the @code{passthrough} option should be used instead.
10527 Numerical values are deprecated, and should be dropped in favor of
10528 symbolic constants.
10531 Do not apply the transposition if the input geometry matches the one
10532 specified by the specified value. It accepts the following values:
10535 Always apply transposition.
10537 Preserve portrait geometry (when @var{height} >= @var{width}).
10539 Preserve landscape geometry (when @var{width} >= @var{height}).
10542 Default value is @code{none}.
10545 For example to rotate by 90 degrees clockwise and preserve portrait
10548 transpose=dir=1:passthrough=portrait
10551 The command above can also be specified as:
10553 transpose=1:portrait
10557 Trim the input so that the output contains one continuous subpart of the input.
10559 It accepts the following parameters:
10562 Specify the time of the start of the kept section, i.e. the frame with the
10563 timestamp @var{start} will be the first frame in the output.
10566 Specify the time of the first frame that will be dropped, i.e. the frame
10567 immediately preceding the one with the timestamp @var{end} will be the last
10568 frame in the output.
10571 This is the same as @var{start}, except this option sets the start timestamp
10572 in timebase units instead of seconds.
10575 This is the same as @var{end}, except this option sets the end timestamp
10576 in timebase units instead of seconds.
10579 The maximum duration of the output in seconds.
10582 The number of the first frame that should be passed to the output.
10585 The number of the first frame that should be dropped.
10588 @option{start}, @option{end}, and @option{duration} are expressed as time
10589 duration specifications; see
10590 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
10591 for the accepted syntax.
10593 Note that the first two sets of the start/end options and the @option{duration}
10594 option look at the frame timestamp, while the _frame variants simply count the
10595 frames that pass through the filter. Also note that this filter does not modify
10596 the timestamps. If you wish for the output timestamps to start at zero, insert a
10597 setpts filter after the trim filter.
10599 If multiple start or end options are set, this filter tries to be greedy and
10600 keep all the frames that match at least one of the specified constraints. To keep
10601 only the part that matches all the constraints at once, chain multiple trim
10604 The defaults are such that all the input is kept. So it is possible to set e.g.
10605 just the end values to keep everything before the specified time.
10610 Drop everything except the second minute of input:
10612 ffmpeg -i INPUT -vf trim=60:120
10616 Keep only the first second:
10618 ffmpeg -i INPUT -vf trim=duration=1
10627 Sharpen or blur the input video.
10629 It accepts the following parameters:
10632 @item luma_msize_x, lx
10633 Set the luma matrix horizontal size. It must be an odd integer between
10634 3 and 63. The default value is 5.
10636 @item luma_msize_y, ly
10637 Set the luma matrix vertical size. It must be an odd integer between 3
10638 and 63. The default value is 5.
10640 @item luma_amount, la
10641 Set the luma effect strength. It must be a floating point number, reasonable
10642 values lay between -1.5 and 1.5.
10644 Negative values will blur the input video, while positive values will
10645 sharpen it, a value of zero will disable the effect.
10647 Default value is 1.0.
10649 @item chroma_msize_x, cx
10650 Set the chroma matrix horizontal size. It must be an odd integer
10651 between 3 and 63. The default value is 5.
10653 @item chroma_msize_y, cy
10654 Set the chroma matrix vertical size. It must be an odd integer
10655 between 3 and 63. The default value is 5.
10657 @item chroma_amount, ca
10658 Set the chroma effect strength. It must be a floating point number, reasonable
10659 values lay between -1.5 and 1.5.
10661 Negative values will blur the input video, while positive values will
10662 sharpen it, a value of zero will disable the effect.
10664 Default value is 0.0.
10667 If set to 1, specify using OpenCL capabilities, only available if
10668 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
10672 All parameters are optional and default to the equivalent of the
10673 string '5:5:1.0:5:5:0.0'.
10675 @subsection Examples
10679 Apply strong luma sharpen effect:
10681 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
10685 Apply a strong blur of both luma and chroma parameters:
10687 unsharp=7:7:-2:7:7:-2
10693 Apply ultra slow/simple postprocessing filter that compresses and decompresses
10694 the image at several (or - in the case of @option{quality} level @code{8} - all)
10695 shifts and average the results.
10697 The way this differs from the behavior of spp is that uspp actually encodes &
10698 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
10699 DCT similar to MJPEG.
10701 The filter accepts the following options:
10705 Set quality. This option defines the number of levels for averaging. It accepts
10706 an integer in the range 0-8. If set to @code{0}, the filter will have no
10707 effect. A value of @code{8} means the higher quality. For each increment of
10708 that value the speed drops by a factor of approximately 2. Default value is
10712 Force a constant quantization parameter. If not set, the filter will use the QP
10713 from the video stream (if available).
10716 @section vectorscope
10718 Display 2 color component values in the two dimensional graph (which is called
10721 This filter accepts the following options:
10725 Set vectorscope mode.
10727 It accepts the following values:
10730 Gray values are displayed on graph, higher brightness means more pixels have
10731 same component color value on location in graph. This is the default mode.
10734 Gray values are displayed on graph. Surrounding pixels values which are not
10735 present in video frame are drawn in gradient of 2 color components which are
10736 set by option @code{x} and @code{y}.
10739 Actual color components values present in video frame are displayed on graph.
10742 Similar as color2 but higher frequency of same values @code{x} and @code{y}
10743 on graph increases value of another color component, which is luminance by
10744 default values of @code{x} and @code{y}.
10747 Actual colors present in video frame are displayed on graph. If two different
10748 colors map to same position on graph then color with higher value of component
10749 not present in graph is picked.
10753 Set which color component will be represented on X-axis. Default is @code{1}.
10756 Set which color component will be represented on Y-axis. Default is @code{2}.
10759 Set intensity, used by modes: gray, color and color3 for increasing brightness
10760 of color component which represents frequency of (X, Y) location in graph.
10765 No envelope, this is default.
10768 Instant envelope, even darkest single pixel will be clearly highlighted.
10771 Hold maximum and minimum values presented in graph over time. This way you
10772 can still spot out of range values without constantly looking at vectorscope.
10775 Peak and instant envelope combined together.
10779 @anchor{vidstabdetect}
10780 @section vidstabdetect
10782 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
10783 @ref{vidstabtransform} for pass 2.
10785 This filter generates a file with relative translation and rotation
10786 transform information about subsequent frames, which is then used by
10787 the @ref{vidstabtransform} filter.
10789 To enable compilation of this filter you need to configure FFmpeg with
10790 @code{--enable-libvidstab}.
10792 This filter accepts the following options:
10796 Set the path to the file used to write the transforms information.
10797 Default value is @file{transforms.trf}.
10800 Set how shaky the video is and how quick the camera is. It accepts an
10801 integer in the range 1-10, a value of 1 means little shakiness, a
10802 value of 10 means strong shakiness. Default value is 5.
10805 Set the accuracy of the detection process. It must be a value in the
10806 range 1-15. A value of 1 means low accuracy, a value of 15 means high
10807 accuracy. Default value is 15.
10810 Set stepsize of the search process. The region around minimum is
10811 scanned with 1 pixel resolution. Default value is 6.
10814 Set minimum contrast. Below this value a local measurement field is
10815 discarded. Must be a floating point value in the range 0-1. Default
10819 Set reference frame number for tripod mode.
10821 If enabled, the motion of the frames is compared to a reference frame
10822 in the filtered stream, identified by the specified number. The idea
10823 is to compensate all movements in a more-or-less static scene and keep
10824 the camera view absolutely still.
10826 If set to 0, it is disabled. The frames are counted starting from 1.
10829 Show fields and transforms in the resulting frames. It accepts an
10830 integer in the range 0-2. Default value is 0, which disables any
10834 @subsection Examples
10838 Use default values:
10844 Analyze strongly shaky movie and put the results in file
10845 @file{mytransforms.trf}:
10847 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
10851 Visualize the result of internal transformations in the resulting
10854 vidstabdetect=show=1
10858 Analyze a video with medium shakiness using @command{ffmpeg}:
10860 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
10864 @anchor{vidstabtransform}
10865 @section vidstabtransform
10867 Video stabilization/deshaking: pass 2 of 2,
10868 see @ref{vidstabdetect} for pass 1.
10870 Read a file with transform information for each frame and
10871 apply/compensate them. Together with the @ref{vidstabdetect}
10872 filter this can be used to deshake videos. See also
10873 @url{http://public.hronopik.de/vid.stab}. It is important to also use
10874 the @ref{unsharp} filter, see below.
10876 To enable compilation of this filter you need to configure FFmpeg with
10877 @code{--enable-libvidstab}.
10879 @subsection Options
10883 Set path to the file used to read the transforms. Default value is
10884 @file{transforms.trf}.
10887 Set the number of frames (value*2 + 1) used for lowpass filtering the
10888 camera movements. Default value is 10.
10890 For example a number of 10 means that 21 frames are used (10 in the
10891 past and 10 in the future) to smoothen the motion in the video. A
10892 larger value leads to a smoother video, but limits the acceleration of
10893 the camera (pan/tilt movements). 0 is a special case where a static
10894 camera is simulated.
10897 Set the camera path optimization algorithm.
10899 Accepted values are:
10902 gaussian kernel low-pass filter on camera motion (default)
10904 averaging on transformations
10908 Set maximal number of pixels to translate frames. Default value is -1,
10912 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
10913 value is -1, meaning no limit.
10916 Specify how to deal with borders that may be visible due to movement
10919 Available values are:
10922 keep image information from previous frame (default)
10924 fill the border black
10928 Invert transforms if set to 1. Default value is 0.
10931 Consider transforms as relative to previous frame if set to 1,
10932 absolute if set to 0. Default value is 0.
10935 Set percentage to zoom. A positive value will result in a zoom-in
10936 effect, a negative value in a zoom-out effect. Default value is 0 (no
10940 Set optimal zooming to avoid borders.
10942 Accepted values are:
10947 optimal static zoom value is determined (only very strong movements
10948 will lead to visible borders) (default)
10950 optimal adaptive zoom value is determined (no borders will be
10951 visible), see @option{zoomspeed}
10954 Note that the value given at zoom is added to the one calculated here.
10957 Set percent to zoom maximally each frame (enabled when
10958 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
10962 Specify type of interpolation.
10964 Available values are:
10969 linear only horizontal
10971 linear in both directions (default)
10973 cubic in both directions (slow)
10977 Enable virtual tripod mode if set to 1, which is equivalent to
10978 @code{relative=0:smoothing=0}. Default value is 0.
10980 Use also @code{tripod} option of @ref{vidstabdetect}.
10983 Increase log verbosity if set to 1. Also the detected global motions
10984 are written to the temporary file @file{global_motions.trf}. Default
10988 @subsection Examples
10992 Use @command{ffmpeg} for a typical stabilization with default values:
10994 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
10997 Note the use of the @ref{unsharp} filter which is always recommended.
11000 Zoom in a bit more and load transform data from a given file:
11002 vidstabtransform=zoom=5:input="mytransforms.trf"
11006 Smoothen the video even more:
11008 vidstabtransform=smoothing=30
11014 Flip the input video vertically.
11016 For example, to vertically flip a video with @command{ffmpeg}:
11018 ffmpeg -i in.avi -vf "vflip" out.avi
11024 Make or reverse a natural vignetting effect.
11026 The filter accepts the following options:
11030 Set lens angle expression as a number of radians.
11032 The value is clipped in the @code{[0,PI/2]} range.
11034 Default value: @code{"PI/5"}
11038 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
11042 Set forward/backward mode.
11044 Available modes are:
11047 The larger the distance from the central point, the darker the image becomes.
11050 The larger the distance from the central point, the brighter the image becomes.
11051 This can be used to reverse a vignette effect, though there is no automatic
11052 detection to extract the lens @option{angle} and other settings (yet). It can
11053 also be used to create a burning effect.
11056 Default value is @samp{forward}.
11059 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
11061 It accepts the following values:
11064 Evaluate expressions only once during the filter initialization.
11067 Evaluate expressions for each incoming frame. This is way slower than the
11068 @samp{init} mode since it requires all the scalers to be re-computed, but it
11069 allows advanced dynamic expressions.
11072 Default value is @samp{init}.
11075 Set dithering to reduce the circular banding effects. Default is @code{1}
11079 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
11080 Setting this value to the SAR of the input will make a rectangular vignetting
11081 following the dimensions of the video.
11083 Default is @code{1/1}.
11086 @subsection Expressions
11088 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
11089 following parameters.
11094 input width and height
11097 the number of input frame, starting from 0
11100 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
11101 @var{TB} units, NAN if undefined
11104 frame rate of the input video, NAN if the input frame rate is unknown
11107 the PTS (Presentation TimeStamp) of the filtered video frame,
11108 expressed in seconds, NAN if undefined
11111 time base of the input video
11115 @subsection Examples
11119 Apply simple strong vignetting effect:
11125 Make a flickering vignetting:
11127 vignette='PI/4+random(1)*PI/50':eval=frame
11133 Stack input videos vertically.
11135 All streams must be of same pixel format and of same width.
11137 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
11138 to create same output.
11140 The filter accept the following option:
11144 Set number of input streams. Default is 2.
11149 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
11150 Deinterlacing Filter").
11152 Based on the process described by Martin Weston for BBC R&D, and
11153 implemented based on the de-interlace algorithm written by Jim
11154 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
11155 uses filter coefficients calculated by BBC R&D.
11157 There are two sets of filter coefficients, so called "simple":
11158 and "complex". Which set of filter coefficients is used can
11159 be set by passing an optional parameter:
11163 Set the interlacing filter coefficients. Accepts one of the following values:
11167 Simple filter coefficient set.
11169 More-complex filter coefficient set.
11171 Default value is @samp{complex}.
11174 Specify which frames to deinterlace. Accept one of the following values:
11178 Deinterlace all frames,
11180 Only deinterlace frames marked as interlaced.
11183 Default value is @samp{all}.
11187 Video waveform monitor.
11189 The waveform monitor plots color component intensity. By default luminance
11190 only. Each column of the waveform corresponds to a column of pixels in the
11193 It accepts the following options:
11197 Can be either @code{row}, or @code{column}. Default is @code{column}.
11198 In row mode, the graph on the left side represents color component value 0 and
11199 the right side represents value = 255. In column mode, the top side represents
11200 color component value = 0 and bottom side represents value = 255.
11203 Set intensity. Smaller values are useful to find out how many values of the same
11204 luminance are distributed across input rows/columns.
11205 Default value is @code{0.04}. Allowed range is [0, 1].
11208 Set mirroring mode. @code{0} means unmirrored, @code{1} means mirrored.
11209 In mirrored mode, higher values will be represented on the left
11210 side for @code{row} mode and at the top for @code{column} mode. Default is
11211 @code{1} (mirrored).
11215 It accepts the following values:
11218 Presents information identical to that in the @code{parade}, except
11219 that the graphs representing color components are superimposed directly
11222 This display mode makes it easier to spot relative differences or similarities
11223 in overlapping areas of the color components that are supposed to be identical,
11224 such as neutral whites, grays, or blacks.
11227 Display separate graph for the color components side by side in
11228 @code{row} mode or one below the other in @code{column} mode.
11230 Using this display mode makes it easy to spot color casts in the highlights
11231 and shadows of an image, by comparing the contours of the top and the bottom
11232 graphs of each waveform. Since whites, grays, and blacks are characterized
11233 by exactly equal amounts of red, green, and blue, neutral areas of the picture
11234 should display three waveforms of roughly equal width/height. If not, the
11235 correction is easy to perform by making level adjustments the three waveforms.
11237 Default is @code{parade}.
11239 @item components, c
11240 Set which color components to display. Default is 1, which means only luminance
11241 or red color component if input is in RGB colorspace. If is set for example to
11242 7 it will display all 3 (if) available color components.
11247 No envelope, this is default.
11250 Instant envelope, minimum and maximum values presented in graph will be easily
11251 visible even with small @code{step} value.
11254 Hold minimum and maximum values presented in graph across time. This way you
11255 can still spot out of range values without constantly looking at waveforms.
11258 Peak and instant envelope combined together.
11264 No filtering, this is default.
11267 Luma and chroma combined together.
11270 Similar as above, but shows difference between blue and red chroma.
11273 Displays only chroma.
11276 Similar as above, but shows difference between blue and red chroma.
11279 Displays actual color value on waveform.
11284 Apply the xBR high-quality magnification filter which is designed for pixel
11285 art. It follows a set of edge-detection rules, see
11286 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
11288 It accepts the following option:
11292 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
11293 @code{3xBR} and @code{4} for @code{4xBR}.
11294 Default is @code{3}.
11300 Deinterlace the input video ("yadif" means "yet another deinterlacing
11303 It accepts the following parameters:
11309 The interlacing mode to adopt. It accepts one of the following values:
11312 @item 0, send_frame
11313 Output one frame for each frame.
11314 @item 1, send_field
11315 Output one frame for each field.
11316 @item 2, send_frame_nospatial
11317 Like @code{send_frame}, but it skips the spatial interlacing check.
11318 @item 3, send_field_nospatial
11319 Like @code{send_field}, but it skips the spatial interlacing check.
11322 The default value is @code{send_frame}.
11325 The picture field parity assumed for the input interlaced video. It accepts one
11326 of the following values:
11330 Assume the top field is first.
11332 Assume the bottom field is first.
11334 Enable automatic detection of field parity.
11337 The default value is @code{auto}.
11338 If the interlacing is unknown or the decoder does not export this information,
11339 top field first will be assumed.
11342 Specify which frames to deinterlace. Accept one of the following
11347 Deinterlace all frames.
11348 @item 1, interlaced
11349 Only deinterlace frames marked as interlaced.
11352 The default value is @code{all}.
11357 Apply Zoom & Pan effect.
11359 This filter accepts the following options:
11363 Set the zoom expression. Default is 1.
11367 Set the x and y expression. Default is 0.
11370 Set the duration expression in number of frames.
11371 This sets for how many number of frames effect will last for
11372 single input image.
11375 Set the output image size, default is 'hd720'.
11378 Each expression can contain the following constants:
11397 Output frame count.
11401 Last calculated 'x' and 'y' position from 'x' and 'y' expression
11402 for current input frame.
11406 'x' and 'y' of last output frame of previous input frame or 0 when there was
11407 not yet such frame (first input frame).
11410 Last calculated zoom from 'z' expression for current input frame.
11413 Last calculated zoom of last output frame of previous input frame.
11416 Number of output frames for current input frame. Calculated from 'd' expression
11417 for each input frame.
11420 number of output frames created for previous input frame
11423 Rational number: input width / input height
11426 sample aspect ratio
11429 display aspect ratio
11433 @subsection Examples
11437 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
11439 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
11443 Zoom-in up to 1.5 and pan always at center of picture:
11445 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
11449 @c man end VIDEO FILTERS
11451 @chapter Video Sources
11452 @c man begin VIDEO SOURCES
11454 Below is a description of the currently available video sources.
11458 Buffer video frames, and make them available to the filter chain.
11460 This source is mainly intended for a programmatic use, in particular
11461 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
11463 It accepts the following parameters:
11468 Specify the size (width and height) of the buffered video frames. For the
11469 syntax of this option, check the
11470 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11473 The input video width.
11476 The input video height.
11479 A string representing the pixel format of the buffered video frames.
11480 It may be a number corresponding to a pixel format, or a pixel format
11484 Specify the timebase assumed by the timestamps of the buffered frames.
11487 Specify the frame rate expected for the video stream.
11489 @item pixel_aspect, sar
11490 The sample (pixel) aspect ratio of the input video.
11493 Specify the optional parameters to be used for the scale filter which
11494 is automatically inserted when an input change is detected in the
11495 input size or format.
11500 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
11503 will instruct the source to accept video frames with size 320x240 and
11504 with format "yuv410p", assuming 1/24 as the timestamps timebase and
11505 square pixels (1:1 sample aspect ratio).
11506 Since the pixel format with name "yuv410p" corresponds to the number 6
11507 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
11508 this example corresponds to:
11510 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
11513 Alternatively, the options can be specified as a flat string, but this
11514 syntax is deprecated:
11516 @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}]
11520 Create a pattern generated by an elementary cellular automaton.
11522 The initial state of the cellular automaton can be defined through the
11523 @option{filename}, and @option{pattern} options. If such options are
11524 not specified an initial state is created randomly.
11526 At each new frame a new row in the video is filled with the result of
11527 the cellular automaton next generation. The behavior when the whole
11528 frame is filled is defined by the @option{scroll} option.
11530 This source accepts the following options:
11534 Read the initial cellular automaton state, i.e. the starting row, from
11535 the specified file.
11536 In the file, each non-whitespace character is considered an alive
11537 cell, a newline will terminate the row, and further characters in the
11538 file will be ignored.
11541 Read the initial cellular automaton state, i.e. the starting row, from
11542 the specified string.
11544 Each non-whitespace character in the string is considered an alive
11545 cell, a newline will terminate the row, and further characters in the
11546 string will be ignored.
11549 Set the video rate, that is the number of frames generated per second.
11552 @item random_fill_ratio, ratio
11553 Set the random fill ratio for the initial cellular automaton row. It
11554 is a floating point number value ranging from 0 to 1, defaults to
11557 This option is ignored when a file or a pattern is specified.
11559 @item random_seed, seed
11560 Set the seed for filling randomly the initial row, must be an integer
11561 included between 0 and UINT32_MAX. If not specified, or if explicitly
11562 set to -1, the filter will try to use a good random seed on a best
11566 Set the cellular automaton rule, it is a number ranging from 0 to 255.
11567 Default value is 110.
11570 Set the size of the output video. For the syntax of this option, check the
11571 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11573 If @option{filename} or @option{pattern} is specified, the size is set
11574 by default to the width of the specified initial state row, and the
11575 height is set to @var{width} * PHI.
11577 If @option{size} is set, it must contain the width of the specified
11578 pattern string, and the specified pattern will be centered in the
11581 If a filename or a pattern string is not specified, the size value
11582 defaults to "320x518" (used for a randomly generated initial state).
11585 If set to 1, scroll the output upward when all the rows in the output
11586 have been already filled. If set to 0, the new generated row will be
11587 written over the top row just after the bottom row is filled.
11590 @item start_full, full
11591 If set to 1, completely fill the output with generated rows before
11592 outputting the first frame.
11593 This is the default behavior, for disabling set the value to 0.
11596 If set to 1, stitch the left and right row edges together.
11597 This is the default behavior, for disabling set the value to 0.
11600 @subsection Examples
11604 Read the initial state from @file{pattern}, and specify an output of
11607 cellauto=f=pattern:s=200x400
11611 Generate a random initial row with a width of 200 cells, with a fill
11614 cellauto=ratio=2/3:s=200x200
11618 Create a pattern generated by rule 18 starting by a single alive cell
11619 centered on an initial row with width 100:
11621 cellauto=p=@@:s=100x400:full=0:rule=18
11625 Specify a more elaborated initial pattern:
11627 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
11632 @section mandelbrot
11634 Generate a Mandelbrot set fractal, and progressively zoom towards the
11635 point specified with @var{start_x} and @var{start_y}.
11637 This source accepts the following options:
11642 Set the terminal pts value. Default value is 400.
11645 Set the terminal scale value.
11646 Must be a floating point value. Default value is 0.3.
11649 Set the inner coloring mode, that is the algorithm used to draw the
11650 Mandelbrot fractal internal region.
11652 It shall assume one of the following values:
11657 Show time until convergence.
11659 Set color based on point closest to the origin of the iterations.
11664 Default value is @var{mincol}.
11667 Set the bailout value. Default value is 10.0.
11670 Set the maximum of iterations performed by the rendering
11671 algorithm. Default value is 7189.
11674 Set outer coloring mode.
11675 It shall assume one of following values:
11677 @item iteration_count
11678 Set iteration cound mode.
11679 @item normalized_iteration_count
11680 set normalized iteration count mode.
11682 Default value is @var{normalized_iteration_count}.
11685 Set frame rate, expressed as number of frames per second. Default
11689 Set frame size. For the syntax of this option, check the "Video
11690 size" section in the ffmpeg-utils manual. Default value is "640x480".
11693 Set the initial scale value. Default value is 3.0.
11696 Set the initial x position. Must be a floating point value between
11697 -100 and 100. Default value is -0.743643887037158704752191506114774.
11700 Set the initial y position. Must be a floating point value between
11701 -100 and 100. Default value is -0.131825904205311970493132056385139.
11706 Generate various test patterns, as generated by the MPlayer test filter.
11708 The size of the generated video is fixed, and is 256x256.
11709 This source is useful in particular for testing encoding features.
11711 This source accepts the following options:
11716 Specify the frame rate of the sourced video, as the number of frames
11717 generated per second. It has to be a string in the format
11718 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
11719 number or a valid video frame rate abbreviation. The default value is
11723 Set the duration of the sourced video. See
11724 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
11725 for the accepted syntax.
11727 If not specified, or the expressed duration is negative, the video is
11728 supposed to be generated forever.
11732 Set the number or the name of the test to perform. Supported tests are:
11748 Default value is "all", which will cycle through the list of all tests.
11753 mptestsrc=t=dc_luma
11756 will generate a "dc_luma" test pattern.
11758 @section frei0r_src
11760 Provide a frei0r source.
11762 To enable compilation of this filter you need to install the frei0r
11763 header and configure FFmpeg with @code{--enable-frei0r}.
11765 This source accepts the following parameters:
11770 The size of the video to generate. For the syntax of this option, check the
11771 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11774 The framerate of the generated video. It may be a string of the form
11775 @var{num}/@var{den} or a frame rate abbreviation.
11778 The name to the frei0r source to load. For more information regarding frei0r and
11779 how to set the parameters, read the @ref{frei0r} section in the video filters
11782 @item filter_params
11783 A '|'-separated list of parameters to pass to the frei0r source.
11787 For example, to generate a frei0r partik0l source with size 200x200
11788 and frame rate 10 which is overlaid on the overlay filter main input:
11790 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
11795 Generate a life pattern.
11797 This source is based on a generalization of John Conway's life game.
11799 The sourced input represents a life grid, each pixel represents a cell
11800 which can be in one of two possible states, alive or dead. Every cell
11801 interacts with its eight neighbours, which are the cells that are
11802 horizontally, vertically, or diagonally adjacent.
11804 At each interaction the grid evolves according to the adopted rule,
11805 which specifies the number of neighbor alive cells which will make a
11806 cell stay alive or born. The @option{rule} option allows one to specify
11809 This source accepts the following options:
11813 Set the file from which to read the initial grid state. In the file,
11814 each non-whitespace character is considered an alive cell, and newline
11815 is used to delimit the end of each row.
11817 If this option is not specified, the initial grid is generated
11821 Set the video rate, that is the number of frames generated per second.
11824 @item random_fill_ratio, ratio
11825 Set the random fill ratio for the initial random grid. It is a
11826 floating point number value ranging from 0 to 1, defaults to 1/PHI.
11827 It is ignored when a file is specified.
11829 @item random_seed, seed
11830 Set the seed for filling the initial random grid, must be an integer
11831 included between 0 and UINT32_MAX. If not specified, or if explicitly
11832 set to -1, the filter will try to use a good random seed on a best
11838 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
11839 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
11840 @var{NS} specifies the number of alive neighbor cells which make a
11841 live cell stay alive, and @var{NB} the number of alive neighbor cells
11842 which make a dead cell to become alive (i.e. to "born").
11843 "s" and "b" can be used in place of "S" and "B", respectively.
11845 Alternatively a rule can be specified by an 18-bits integer. The 9
11846 high order bits are used to encode the next cell state if it is alive
11847 for each number of neighbor alive cells, the low order bits specify
11848 the rule for "borning" new cells. Higher order bits encode for an
11849 higher number of neighbor cells.
11850 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
11851 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
11853 Default value is "S23/B3", which is the original Conway's game of life
11854 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
11855 cells, and will born a new cell if there are three alive cells around
11859 Set the size of the output video. For the syntax of this option, check the
11860 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11862 If @option{filename} is specified, the size is set by default to the
11863 same size of the input file. If @option{size} is set, it must contain
11864 the size specified in the input file, and the initial grid defined in
11865 that file is centered in the larger resulting area.
11867 If a filename is not specified, the size value defaults to "320x240"
11868 (used for a randomly generated initial grid).
11871 If set to 1, stitch the left and right grid edges together, and the
11872 top and bottom edges also. Defaults to 1.
11875 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
11876 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
11877 value from 0 to 255.
11880 Set the color of living (or new born) cells.
11883 Set the color of dead cells. If @option{mold} is set, this is the first color
11884 used to represent a dead cell.
11887 Set mold color, for definitely dead and moldy cells.
11889 For the syntax of these 3 color options, check the "Color" section in the
11890 ffmpeg-utils manual.
11893 @subsection Examples
11897 Read a grid from @file{pattern}, and center it on a grid of size
11900 life=f=pattern:s=300x300
11904 Generate a random grid of size 200x200, with a fill ratio of 2/3:
11906 life=ratio=2/3:s=200x200
11910 Specify a custom rule for evolving a randomly generated grid:
11916 Full example with slow death effect (mold) using @command{ffplay}:
11918 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
11925 @anchor{haldclutsrc}
11927 @anchor{rgbtestsrc}
11929 @anchor{smptehdbars}
11931 @section allrgb, allyuv, color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
11933 The @code{allrgb} source returns frames of size 4096x4096 of all rgb colors.
11935 The @code{allyuv} source returns frames of size 4096x4096 of all yuv colors.
11937 The @code{color} source provides an uniformly colored input.
11939 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
11940 @ref{haldclut} filter.
11942 The @code{nullsrc} source returns unprocessed video frames. It is
11943 mainly useful to be employed in analysis / debugging tools, or as the
11944 source for filters which ignore the input data.
11946 The @code{rgbtestsrc} source generates an RGB test pattern useful for
11947 detecting RGB vs BGR issues. You should see a red, green and blue
11948 stripe from top to bottom.
11950 The @code{smptebars} source generates a color bars pattern, based on
11951 the SMPTE Engineering Guideline EG 1-1990.
11953 The @code{smptehdbars} source generates a color bars pattern, based on
11954 the SMPTE RP 219-2002.
11956 The @code{testsrc} source generates a test video pattern, showing a
11957 color pattern, a scrolling gradient and a timestamp. This is mainly
11958 intended for testing purposes.
11960 The sources accept the following parameters:
11965 Specify the color of the source, only available in the @code{color}
11966 source. For the syntax of this option, check the "Color" section in the
11967 ffmpeg-utils manual.
11970 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
11971 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
11972 pixels to be used as identity matrix for 3D lookup tables. Each component is
11973 coded on a @code{1/(N*N)} scale.
11976 Specify the size of the sourced video. For the syntax of this option, check the
11977 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11978 The default value is @code{320x240}.
11980 This option is not available with the @code{haldclutsrc} filter.
11983 Specify the frame rate of the sourced video, as the number of frames
11984 generated per second. It has to be a string in the format
11985 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
11986 number or a valid video frame rate abbreviation. The default value is
11990 Set the sample aspect ratio of the sourced video.
11993 Set the duration of the sourced video. See
11994 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
11995 for the accepted syntax.
11997 If not specified, or the expressed duration is negative, the video is
11998 supposed to be generated forever.
12001 Set the number of decimals to show in the timestamp, only available in the
12002 @code{testsrc} source.
12004 The displayed timestamp value will correspond to the original
12005 timestamp value multiplied by the power of 10 of the specified
12006 value. Default value is 0.
12009 For example the following:
12011 testsrc=duration=5.3:size=qcif:rate=10
12014 will generate a video with a duration of 5.3 seconds, with size
12015 176x144 and a frame rate of 10 frames per second.
12017 The following graph description will generate a red source
12018 with an opacity of 0.2, with size "qcif" and a frame rate of 10
12021 color=c=red@@0.2:s=qcif:r=10
12024 If the input content is to be ignored, @code{nullsrc} can be used. The
12025 following command generates noise in the luminance plane by employing
12026 the @code{geq} filter:
12028 nullsrc=s=256x256, geq=random(1)*255:128:128
12031 @subsection Commands
12033 The @code{color} source supports the following commands:
12037 Set the color of the created image. Accepts the same syntax of the
12038 corresponding @option{color} option.
12041 @c man end VIDEO SOURCES
12043 @chapter Video Sinks
12044 @c man begin VIDEO SINKS
12046 Below is a description of the currently available video sinks.
12048 @section buffersink
12050 Buffer video frames, and make them available to the end of the filter
12053 This sink is mainly intended for programmatic use, in particular
12054 through the interface defined in @file{libavfilter/buffersink.h}
12055 or the options system.
12057 It accepts a pointer to an AVBufferSinkContext structure, which
12058 defines the incoming buffers' formats, to be passed as the opaque
12059 parameter to @code{avfilter_init_filter} for initialization.
12063 Null video sink: do absolutely nothing with the input video. It is
12064 mainly useful as a template and for use in analysis / debugging
12067 @c man end VIDEO SINKS
12069 @chapter Multimedia Filters
12070 @c man begin MULTIMEDIA FILTERS
12072 Below is a description of the currently available multimedia filters.
12074 @section aphasemeter
12076 Convert input audio to a video output, displaying the audio phase.
12078 The filter accepts the following options:
12082 Set the output frame rate. Default value is @code{25}.
12085 Set the video size for the output. For the syntax of this option, check the
12086 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12087 Default value is @code{800x400}.
12092 Specify the red, green, blue contrast. Default values are @code{2},
12093 @code{7} and @code{1}.
12094 Allowed range is @code{[0, 255]}.
12097 Set color which will be used for drawing median phase. If color is
12098 @code{none} which is default, no median phase value will be drawn.
12101 The filter also exports the frame metadata @code{lavfi.aphasemeter.phase} which
12102 represents mean phase of current audio frame. Value is in range @code{[-1, 1]}.
12103 The @code{-1} means left and right channels are completely out of phase and
12104 @code{1} means channels are in phase.
12106 @section avectorscope
12108 Convert input audio to a video output, representing the audio vector
12111 The filter is used to measure the difference between channels of stereo
12112 audio stream. A monoaural signal, consisting of identical left and right
12113 signal, results in straight vertical line. Any stereo separation is visible
12114 as a deviation from this line, creating a Lissajous figure.
12115 If the straight (or deviation from it) but horizontal line appears this
12116 indicates that the left and right channels are out of phase.
12118 The filter accepts the following options:
12122 Set the vectorscope mode.
12124 Available values are:
12127 Lissajous rotated by 45 degrees.
12130 Same as above but not rotated.
12133 Shape resembling half of circle.
12136 Default value is @samp{lissajous}.
12139 Set the video size for the output. For the syntax of this option, check the
12140 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12141 Default value is @code{400x400}.
12144 Set the output frame rate. Default value is @code{25}.
12150 Specify the red, green, blue and alpha contrast. Default values are @code{40},
12151 @code{160}, @code{80} and @code{255}.
12152 Allowed range is @code{[0, 255]}.
12158 Specify the red, green, blue and alpha fade. Default values are @code{15},
12159 @code{10}, @code{5} and @code{5}.
12160 Allowed range is @code{[0, 255]}.
12163 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
12166 @subsection Examples
12170 Complete example using @command{ffplay}:
12172 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
12173 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
12179 Concatenate audio and video streams, joining them together one after the
12182 The filter works on segments of synchronized video and audio streams. All
12183 segments must have the same number of streams of each type, and that will
12184 also be the number of streams at output.
12186 The filter accepts the following options:
12191 Set the number of segments. Default is 2.
12194 Set the number of output video streams, that is also the number of video
12195 streams in each segment. Default is 1.
12198 Set the number of output audio streams, that is also the number of audio
12199 streams in each segment. Default is 0.
12202 Activate unsafe mode: do not fail if segments have a different format.
12206 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
12207 @var{a} audio outputs.
12209 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
12210 segment, in the same order as the outputs, then the inputs for the second
12213 Related streams do not always have exactly the same duration, for various
12214 reasons including codec frame size or sloppy authoring. For that reason,
12215 related synchronized streams (e.g. a video and its audio track) should be
12216 concatenated at once. The concat filter will use the duration of the longest
12217 stream in each segment (except the last one), and if necessary pad shorter
12218 audio streams with silence.
12220 For this filter to work correctly, all segments must start at timestamp 0.
12222 All corresponding streams must have the same parameters in all segments; the
12223 filtering system will automatically select a common pixel format for video
12224 streams, and a common sample format, sample rate and channel layout for
12225 audio streams, but other settings, such as resolution, must be converted
12226 explicitly by the user.
12228 Different frame rates are acceptable but will result in variable frame rate
12229 at output; be sure to configure the output file to handle it.
12231 @subsection Examples
12235 Concatenate an opening, an episode and an ending, all in bilingual version
12236 (video in stream 0, audio in streams 1 and 2):
12238 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
12239 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
12240 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
12241 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
12245 Concatenate two parts, handling audio and video separately, using the
12246 (a)movie sources, and adjusting the resolution:
12248 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
12249 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
12250 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
12252 Note that a desync will happen at the stitch if the audio and video streams
12253 do not have exactly the same duration in the first file.
12260 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
12261 it unchanged. By default, it logs a message at a frequency of 10Hz with the
12262 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
12263 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
12265 The filter also has a video output (see the @var{video} option) with a real
12266 time graph to observe the loudness evolution. The graphic contains the logged
12267 message mentioned above, so it is not printed anymore when this option is set,
12268 unless the verbose logging is set. The main graphing area contains the
12269 short-term loudness (3 seconds of analysis), and the gauge on the right is for
12270 the momentary loudness (400 milliseconds).
12272 More information about the Loudness Recommendation EBU R128 on
12273 @url{http://tech.ebu.ch/loudness}.
12275 The filter accepts the following options:
12280 Activate the video output. The audio stream is passed unchanged whether this
12281 option is set or no. The video stream will be the first output stream if
12282 activated. Default is @code{0}.
12285 Set the video size. This option is for video only. For the syntax of this
12287 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12288 Default and minimum resolution is @code{640x480}.
12291 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
12292 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
12293 other integer value between this range is allowed.
12296 Set metadata injection. If set to @code{1}, the audio input will be segmented
12297 into 100ms output frames, each of them containing various loudness information
12298 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
12300 Default is @code{0}.
12303 Force the frame logging level.
12305 Available values are:
12308 information logging level
12310 verbose logging level
12313 By default, the logging level is set to @var{info}. If the @option{video} or
12314 the @option{metadata} options are set, it switches to @var{verbose}.
12319 Available modes can be cumulated (the option is a @code{flag} type). Possible
12323 Disable any peak mode (default).
12325 Enable sample-peak mode.
12327 Simple peak mode looking for the higher sample value. It logs a message
12328 for sample-peak (identified by @code{SPK}).
12330 Enable true-peak mode.
12332 If enabled, the peak lookup is done on an over-sampled version of the input
12333 stream for better peak accuracy. It logs a message for true-peak.
12334 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
12335 This mode requires a build with @code{libswresample}.
12340 @subsection Examples
12344 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
12346 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
12350 Run an analysis with @command{ffmpeg}:
12352 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
12356 @section interleave, ainterleave
12358 Temporally interleave frames from several inputs.
12360 @code{interleave} works with video inputs, @code{ainterleave} with audio.
12362 These filters read frames from several inputs and send the oldest
12363 queued frame to the output.
12365 Input streams must have a well defined, monotonically increasing frame
12368 In order to submit one frame to output, these filters need to enqueue
12369 at least one frame for each input, so they cannot work in case one
12370 input is not yet terminated and will not receive incoming frames.
12372 For example consider the case when one input is a @code{select} filter
12373 which always drop input frames. The @code{interleave} filter will keep
12374 reading from that input, but it will never be able to send new frames
12375 to output until the input will send an end-of-stream signal.
12377 Also, depending on inputs synchronization, the filters will drop
12378 frames in case one input receives more frames than the other ones, and
12379 the queue is already filled.
12381 These filters accept the following options:
12385 Set the number of different inputs, it is 2 by default.
12388 @subsection Examples
12392 Interleave frames belonging to different streams using @command{ffmpeg}:
12394 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
12398 Add flickering blur effect:
12400 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
12404 @section perms, aperms
12406 Set read/write permissions for the output frames.
12408 These filters are mainly aimed at developers to test direct path in the
12409 following filter in the filtergraph.
12411 The filters accept the following options:
12415 Select the permissions mode.
12417 It accepts the following values:
12420 Do nothing. This is the default.
12422 Set all the output frames read-only.
12424 Set all the output frames directly writable.
12426 Make the frame read-only if writable, and writable if read-only.
12428 Set each output frame read-only or writable randomly.
12432 Set the seed for the @var{random} mode, must be an integer included between
12433 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
12434 @code{-1}, the filter will try to use a good random seed on a best effort
12438 Note: in case of auto-inserted filter between the permission filter and the
12439 following one, the permission might not be received as expected in that
12440 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
12441 perms/aperms filter can avoid this problem.
12443 @section select, aselect
12445 Select frames to pass in output.
12447 This filter accepts the following options:
12452 Set expression, which is evaluated for each input frame.
12454 If the expression is evaluated to zero, the frame is discarded.
12456 If the evaluation result is negative or NaN, the frame is sent to the
12457 first output; otherwise it is sent to the output with index
12458 @code{ceil(val)-1}, assuming that the input index starts from 0.
12460 For example a value of @code{1.2} corresponds to the output with index
12461 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
12464 Set the number of outputs. The output to which to send the selected
12465 frame is based on the result of the evaluation. Default value is 1.
12468 The expression can contain the following constants:
12472 The (sequential) number of the filtered frame, starting from 0.
12475 The (sequential) number of the selected frame, starting from 0.
12477 @item prev_selected_n
12478 The sequential number of the last selected frame. It's NAN if undefined.
12481 The timebase of the input timestamps.
12484 The PTS (Presentation TimeStamp) of the filtered video frame,
12485 expressed in @var{TB} units. It's NAN if undefined.
12488 The PTS of the filtered video frame,
12489 expressed in seconds. It's NAN if undefined.
12492 The PTS of the previously filtered video frame. It's NAN if undefined.
12494 @item prev_selected_pts
12495 The PTS of the last previously filtered video frame. It's NAN if undefined.
12497 @item prev_selected_t
12498 The PTS of the last previously selected video frame. It's NAN if undefined.
12501 The PTS of the first video frame in the video. It's NAN if undefined.
12504 The time of the first video frame in the video. It's NAN if undefined.
12506 @item pict_type @emph{(video only)}
12507 The type of the filtered frame. It can assume one of the following
12519 @item interlace_type @emph{(video only)}
12520 The frame interlace type. It can assume one of the following values:
12523 The frame is progressive (not interlaced).
12525 The frame is top-field-first.
12527 The frame is bottom-field-first.
12530 @item consumed_sample_n @emph{(audio only)}
12531 the number of selected samples before the current frame
12533 @item samples_n @emph{(audio only)}
12534 the number of samples in the current frame
12536 @item sample_rate @emph{(audio only)}
12537 the input sample rate
12540 This is 1 if the filtered frame is a key-frame, 0 otherwise.
12543 the position in the file of the filtered frame, -1 if the information
12544 is not available (e.g. for synthetic video)
12546 @item scene @emph{(video only)}
12547 value between 0 and 1 to indicate a new scene; a low value reflects a low
12548 probability for the current frame to introduce a new scene, while a higher
12549 value means the current frame is more likely to be one (see the example below)
12553 The default value of the select expression is "1".
12555 @subsection Examples
12559 Select all frames in input:
12564 The example above is the same as:
12576 Select only I-frames:
12578 select='eq(pict_type\,I)'
12582 Select one frame every 100:
12584 select='not(mod(n\,100))'
12588 Select only frames contained in the 10-20 time interval:
12590 select=between(t\,10\,20)
12594 Select only I frames contained in the 10-20 time interval:
12596 select=between(t\,10\,20)*eq(pict_type\,I)
12600 Select frames with a minimum distance of 10 seconds:
12602 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
12606 Use aselect to select only audio frames with samples number > 100:
12608 aselect='gt(samples_n\,100)'
12612 Create a mosaic of the first scenes:
12614 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
12617 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
12621 Send even and odd frames to separate outputs, and compose them:
12623 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
12627 @section sendcmd, asendcmd
12629 Send commands to filters in the filtergraph.
12631 These filters read commands to be sent to other filters in the
12634 @code{sendcmd} must be inserted between two video filters,
12635 @code{asendcmd} must be inserted between two audio filters, but apart
12636 from that they act the same way.
12638 The specification of commands can be provided in the filter arguments
12639 with the @var{commands} option, or in a file specified by the
12640 @var{filename} option.
12642 These filters accept the following options:
12645 Set the commands to be read and sent to the other filters.
12647 Set the filename of the commands to be read and sent to the other
12651 @subsection Commands syntax
12653 A commands description consists of a sequence of interval
12654 specifications, comprising a list of commands to be executed when a
12655 particular event related to that interval occurs. The occurring event
12656 is typically the current frame time entering or leaving a given time
12659 An interval is specified by the following syntax:
12661 @var{START}[-@var{END}] @var{COMMANDS};
12664 The time interval is specified by the @var{START} and @var{END} times.
12665 @var{END} is optional and defaults to the maximum time.
12667 The current frame time is considered within the specified interval if
12668 it is included in the interval [@var{START}, @var{END}), that is when
12669 the time is greater or equal to @var{START} and is lesser than
12672 @var{COMMANDS} consists of a sequence of one or more command
12673 specifications, separated by ",", relating to that interval. The
12674 syntax of a command specification is given by:
12676 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
12679 @var{FLAGS} is optional and specifies the type of events relating to
12680 the time interval which enable sending the specified command, and must
12681 be a non-null sequence of identifier flags separated by "+" or "|" and
12682 enclosed between "[" and "]".
12684 The following flags are recognized:
12687 The command is sent when the current frame timestamp enters the
12688 specified interval. In other words, the command is sent when the
12689 previous frame timestamp was not in the given interval, and the
12693 The command is sent when the current frame timestamp leaves the
12694 specified interval. In other words, the command is sent when the
12695 previous frame timestamp was in the given interval, and the
12699 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
12702 @var{TARGET} specifies the target of the command, usually the name of
12703 the filter class or a specific filter instance name.
12705 @var{COMMAND} specifies the name of the command for the target filter.
12707 @var{ARG} is optional and specifies the optional list of argument for
12708 the given @var{COMMAND}.
12710 Between one interval specification and another, whitespaces, or
12711 sequences of characters starting with @code{#} until the end of line,
12712 are ignored and can be used to annotate comments.
12714 A simplified BNF description of the commands specification syntax
12717 @var{COMMAND_FLAG} ::= "enter" | "leave"
12718 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
12719 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
12720 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
12721 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
12722 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
12725 @subsection Examples
12729 Specify audio tempo change at second 4:
12731 asendcmd=c='4.0 atempo tempo 1.5',atempo
12735 Specify a list of drawtext and hue commands in a file.
12737 # show text in the interval 5-10
12738 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
12739 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
12741 # desaturate the image in the interval 15-20
12742 15.0-20.0 [enter] hue s 0,
12743 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
12745 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
12747 # apply an exponential saturation fade-out effect, starting from time 25
12748 25 [enter] hue s exp(25-t)
12751 A filtergraph allowing to read and process the above command list
12752 stored in a file @file{test.cmd}, can be specified with:
12754 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
12759 @section setpts, asetpts
12761 Change the PTS (presentation timestamp) of the input frames.
12763 @code{setpts} works on video frames, @code{asetpts} on audio frames.
12765 This filter accepts the following options:
12770 The expression which is evaluated for each frame to construct its timestamp.
12774 The expression is evaluated through the eval API and can contain the following
12779 frame rate, only defined for constant frame-rate video
12782 The presentation timestamp in input
12785 The count of the input frame for video or the number of consumed samples,
12786 not including the current frame for audio, starting from 0.
12788 @item NB_CONSUMED_SAMPLES
12789 The number of consumed samples, not including the current frame (only
12792 @item NB_SAMPLES, S
12793 The number of samples in the current frame (only audio)
12795 @item SAMPLE_RATE, SR
12796 The audio sample rate.
12799 The PTS of the first frame.
12802 the time in seconds of the first frame
12805 State whether the current frame is interlaced.
12808 the time in seconds of the current frame
12811 original position in the file of the frame, or undefined if undefined
12812 for the current frame
12815 The previous input PTS.
12818 previous input time in seconds
12821 The previous output PTS.
12824 previous output time in seconds
12827 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
12831 The wallclock (RTC) time at the start of the movie in microseconds.
12834 The timebase of the input timestamps.
12838 @subsection Examples
12842 Start counting PTS from zero
12844 setpts=PTS-STARTPTS
12848 Apply fast motion effect:
12854 Apply slow motion effect:
12860 Set fixed rate of 25 frames per second:
12866 Set fixed rate 25 fps with some jitter:
12868 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
12872 Apply an offset of 10 seconds to the input PTS:
12878 Generate timestamps from a "live source" and rebase onto the current timebase:
12880 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
12884 Generate timestamps by counting samples:
12891 @section settb, asettb
12893 Set the timebase to use for the output frames timestamps.
12894 It is mainly useful for testing timebase configuration.
12896 It accepts the following parameters:
12901 The expression which is evaluated into the output timebase.
12905 The value for @option{tb} is an arithmetic expression representing a
12906 rational. The expression can contain the constants "AVTB" (the default
12907 timebase), "intb" (the input timebase) and "sr" (the sample rate,
12908 audio only). Default value is "intb".
12910 @subsection Examples
12914 Set the timebase to 1/25:
12920 Set the timebase to 1/10:
12926 Set the timebase to 1001/1000:
12932 Set the timebase to 2*intb:
12938 Set the default timebase value:
12945 Convert input audio to a video output representing
12946 frequency spectrum logarithmically (using constant Q transform with
12947 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
12949 The filter accepts the following options:
12953 Specify transform volume (multiplier) expression. The expression can contain
12956 @item frequency, freq, f
12957 the frequency where transform is evaluated
12958 @item timeclamp, tc
12959 value of timeclamp option
12963 @item a_weighting(f)
12964 A-weighting of equal loudness
12965 @item b_weighting(f)
12966 B-weighting of equal loudness
12967 @item c_weighting(f)
12968 C-weighting of equal loudness
12970 Default value is @code{16}.
12973 Specify transform length expression. The expression can contain variables:
12975 @item frequency, freq, f
12976 the frequency where transform is evaluated
12977 @item timeclamp, tc
12978 value of timeclamp option
12980 Default value is @code{384/f*tc/(384/f+tc)}.
12983 Specify the transform timeclamp. At low frequency, there is trade-off between
12984 accuracy in time domain and frequency domain. If timeclamp is lower,
12985 event in time domain is represented more accurately (such as fast bass drum),
12986 otherwise event in frequency domain is represented more accurately
12987 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
12990 Specify the transform coeffclamp. If coeffclamp is lower, transform is
12991 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
12992 Default value is @code{1.0}.
12995 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
12996 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
12997 Default value is @code{3.0}.
13000 Specify gamma of bargraph. Acceptable value is [1.0, 7.0].
13001 Default value is @code{1.0}.
13004 Specify font file for use with freetype. If not specified, use embedded font.
13007 Specify font color expression. This is arithmetic expression that should return
13008 integer value 0xRRGGBB. The expression can contain variables:
13010 @item frequency, freq, f
13011 the frequency where transform is evaluated
13012 @item timeclamp, tc
13013 value of timeclamp option
13018 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
13019 @item r(x), g(x), b(x)
13020 red, green, and blue value of intensity x
13022 Default value is @code{st(0, (midi(f)-59.5)/12);
13023 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
13024 r(1-ld(1)) + b(ld(1))}
13027 If set to 1 (the default), the video size is 1920x1080 (full HD),
13028 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
13031 Specify video fps. Default value is @code{25}.
13034 Specify number of transform per frame, so there are fps*count transforms
13035 per second. Note that audio data rate must be divisible by fps*count.
13036 Default value is @code{6}.
13040 @subsection Examples
13044 Playing audio while showing the spectrum:
13046 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
13050 Same as above, but with frame rate 30 fps:
13052 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
13056 Playing at 960x540 and lower CPU usage:
13058 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
13062 A1 and its harmonics: A1, A2, (near)E3, A3:
13064 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),
13065 asplit[a][out1]; [a] showcqt [out0]'
13069 Same as above, but with more accuracy in frequency domain (and slower):
13071 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),
13072 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
13076 B-weighting of equal loudness
13078 volume=16*b_weighting(f)
13084 tlength=100/f*tc/(100/f+tc)
13088 Custom fontcolor, C-note is colored green, others are colored blue
13090 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))'
13094 Custom gamma, now spectrum is linear to the amplitude.
13103 Convert input audio to video output representing the audio power spectrum.
13104 Audio amplitude is on Y-axis while frequency is on X-axis.
13106 The filter accepts the following options:
13110 Specify size of video. For the syntax of this option, check the
13111 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13112 Default is @code{1024x512}.
13116 This set how each frequency bin will be represented.
13118 It accepts the following values:
13124 Default is @code{bar}.
13127 Set amplitude scale.
13129 It accepts the following values:
13143 Default is @code{log}.
13146 Set frequency scale.
13148 It accepts the following values:
13157 Reverse logarithmic scale.
13159 Default is @code{lin}.
13164 It accepts the following values:
13180 Default is @code{w2048}
13183 Set windowing function.
13185 It accepts the following values:
13202 Default is @code{hanning}.
13205 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
13206 which means optimal overlap for selected window function will be picked.
13209 Set time averaging. Setting this to 0 will display current maximal peaks.
13210 Default is @code{1}, which means time averaging is disabled.
13213 Specify list of colors separated by space or by '|' which will be used to
13214 draw channel frequencies. Unrecognized or missing colors will be replaced
13218 @section showspectrum
13220 Convert input audio to a video output, representing the audio frequency
13223 The filter accepts the following options:
13227 Specify the video size for the output. For the syntax of this option, check the
13228 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13229 Default value is @code{640x512}.
13232 Specify how the spectrum should slide along the window.
13234 It accepts the following values:
13237 the samples start again on the left when they reach the right
13239 the samples scroll from right to left
13241 frames are only produced when the samples reach the right
13244 Default value is @code{replace}.
13247 Specify display mode.
13249 It accepts the following values:
13252 all channels are displayed in the same row
13254 all channels are displayed in separate rows
13257 Default value is @samp{combined}.
13260 Specify display color mode.
13262 It accepts the following values:
13265 each channel is displayed in a separate color
13267 each channel is is displayed using the same color scheme
13270 Default value is @samp{channel}.
13273 Specify scale used for calculating intensity color values.
13275 It accepts the following values:
13280 square root, default
13287 Default value is @samp{sqrt}.
13290 Set saturation modifier for displayed colors. Negative values provide
13291 alternative color scheme. @code{0} is no saturation at all.
13292 Saturation must be in [-10.0, 10.0] range.
13293 Default value is @code{1}.
13296 Set window function.
13298 It accepts the following values:
13301 No samples pre-processing (do not expect this to be faster)
13310 Default value is @code{hann}.
13313 The usage is very similar to the showwaves filter; see the examples in that
13316 @subsection Examples
13320 Large window with logarithmic color scaling:
13322 showspectrum=s=1280x480:scale=log
13326 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
13328 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
13329 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
13333 @section showvolume
13335 Convert input audio volume to a video output.
13337 The filter accepts the following options:
13344 Set border width, allowed range is [0, 5]. Default is 1.
13347 Set channel width, allowed range is [40, 1080]. Default is 400.
13350 Set channel height, allowed range is [1, 100]. Default is 20.
13353 Set fade, allowed range is [1, 255]. Default is 20.
13356 Set volume color expression.
13358 The expression can use the following variables:
13362 Current max volume of channel in dB.
13365 Current channel number, starting from 0.
13369 If set, displays channel names. Default is enabled.
13374 Convert input audio to a video output, representing the samples waves.
13376 The filter accepts the following options:
13380 Specify the video size for the output. For the syntax of this option, check the
13381 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13382 Default value is @code{600x240}.
13387 Available values are:
13390 Draw a point for each sample.
13393 Draw a vertical line for each sample.
13396 Draw a point for each sample and a line between them.
13399 Draw a centered vertical line for each sample.
13402 Default value is @code{point}.
13405 Set the number of samples which are printed on the same column. A
13406 larger value will decrease the frame rate. Must be a positive
13407 integer. This option can be set only if the value for @var{rate}
13408 is not explicitly specified.
13411 Set the (approximate) output frame rate. This is done by setting the
13412 option @var{n}. Default value is "25".
13414 @item split_channels
13415 Set if channels should be drawn separately or overlap. Default value is 0.
13419 @subsection Examples
13423 Output the input file audio and the corresponding video representation
13426 amovie=a.mp3,asplit[out0],showwaves[out1]
13430 Create a synthetic signal and show it with showwaves, forcing a
13431 frame rate of 30 frames per second:
13433 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
13437 @section showwavespic
13439 Convert input audio to a single video frame, representing the samples waves.
13441 The filter accepts the following options:
13445 Specify the video size for the output. For the syntax of this option, check the
13446 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13447 Default value is @code{600x240}.
13449 @item split_channels
13450 Set if channels should be drawn separately or overlap. Default value is 0.
13453 @subsection Examples
13457 Extract a channel split representation of the wave form of a whole audio track
13458 in a 1024x800 picture using @command{ffmpeg}:
13460 ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png
13464 @section split, asplit
13466 Split input into several identical outputs.
13468 @code{asplit} works with audio input, @code{split} with video.
13470 The filter accepts a single parameter which specifies the number of outputs. If
13471 unspecified, it defaults to 2.
13473 @subsection Examples
13477 Create two separate outputs from the same input:
13479 [in] split [out0][out1]
13483 To create 3 or more outputs, you need to specify the number of
13486 [in] asplit=3 [out0][out1][out2]
13490 Create two separate outputs from the same input, one cropped and
13493 [in] split [splitout1][splitout2];
13494 [splitout1] crop=100:100:0:0 [cropout];
13495 [splitout2] pad=200:200:100:100 [padout];
13499 Create 5 copies of the input audio with @command{ffmpeg}:
13501 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
13507 Receive commands sent through a libzmq client, and forward them to
13508 filters in the filtergraph.
13510 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
13511 must be inserted between two video filters, @code{azmq} between two
13514 To enable these filters you need to install the libzmq library and
13515 headers and configure FFmpeg with @code{--enable-libzmq}.
13517 For more information about libzmq see:
13518 @url{http://www.zeromq.org/}
13520 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
13521 receives messages sent through a network interface defined by the
13522 @option{bind_address} option.
13524 The received message must be in the form:
13526 @var{TARGET} @var{COMMAND} [@var{ARG}]
13529 @var{TARGET} specifies the target of the command, usually the name of
13530 the filter class or a specific filter instance name.
13532 @var{COMMAND} specifies the name of the command for the target filter.
13534 @var{ARG} is optional and specifies the optional argument list for the
13535 given @var{COMMAND}.
13537 Upon reception, the message is processed and the corresponding command
13538 is injected into the filtergraph. Depending on the result, the filter
13539 will send a reply to the client, adopting the format:
13541 @var{ERROR_CODE} @var{ERROR_REASON}
13545 @var{MESSAGE} is optional.
13547 @subsection Examples
13549 Look at @file{tools/zmqsend} for an example of a zmq client which can
13550 be used to send commands processed by these filters.
13552 Consider the following filtergraph generated by @command{ffplay}
13554 ffplay -dumpgraph 1 -f lavfi "
13555 color=s=100x100:c=red [l];
13556 color=s=100x100:c=blue [r];
13557 nullsrc=s=200x100, zmq [bg];
13558 [bg][l] overlay [bg+l];
13559 [bg+l][r] overlay=x=100 "
13562 To change the color of the left side of the video, the following
13563 command can be used:
13565 echo Parsed_color_0 c yellow | tools/zmqsend
13568 To change the right side:
13570 echo Parsed_color_1 c pink | tools/zmqsend
13573 @c man end MULTIMEDIA FILTERS
13575 @chapter Multimedia Sources
13576 @c man begin MULTIMEDIA SOURCES
13578 Below is a description of the currently available multimedia sources.
13582 This is the same as @ref{movie} source, except it selects an audio
13588 Read audio and/or video stream(s) from a movie container.
13590 It accepts the following parameters:
13594 The name of the resource to read (not necessarily a file; it can also be a
13595 device or a stream accessed through some protocol).
13597 @item format_name, f
13598 Specifies the format assumed for the movie to read, and can be either
13599 the name of a container or an input device. If not specified, the
13600 format is guessed from @var{movie_name} or by probing.
13602 @item seek_point, sp
13603 Specifies the seek point in seconds. The frames will be output
13604 starting from this seek point. The parameter is evaluated with
13605 @code{av_strtod}, so the numerical value may be suffixed by an IS
13606 postfix. The default value is "0".
13609 Specifies the streams to read. Several streams can be specified,
13610 separated by "+". The source will then have as many outputs, in the
13611 same order. The syntax is explained in the ``Stream specifiers''
13612 section in the ffmpeg manual. Two special names, "dv" and "da" specify
13613 respectively the default (best suited) video and audio stream. Default
13614 is "dv", or "da" if the filter is called as "amovie".
13616 @item stream_index, si
13617 Specifies the index of the video stream to read. If the value is -1,
13618 the most suitable video stream will be automatically selected. The default
13619 value is "-1". Deprecated. If the filter is called "amovie", it will select
13620 audio instead of video.
13623 Specifies how many times to read the stream in sequence.
13624 If the value is less than 1, the stream will be read again and again.
13625 Default value is "1".
13627 Note that when the movie is looped the source timestamps are not
13628 changed, so it will generate non monotonically increasing timestamps.
13631 It allows overlaying a second video on top of the main input of
13632 a filtergraph, as shown in this graph:
13634 input -----------> deltapts0 --> overlay --> output
13637 movie --> scale--> deltapts1 -------+
13639 @subsection Examples
13643 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
13644 on top of the input labelled "in":
13646 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
13647 [in] setpts=PTS-STARTPTS [main];
13648 [main][over] overlay=16:16 [out]
13652 Read from a video4linux2 device, and overlay it on top of the input
13655 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
13656 [in] setpts=PTS-STARTPTS [main];
13657 [main][over] overlay=16:16 [out]
13661 Read the first video stream and the audio stream with id 0x81 from
13662 dvd.vob; the video is connected to the pad named "video" and the audio is
13663 connected to the pad named "audio":
13665 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
13669 @c man end MULTIMEDIA SOURCES