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 Apply a two-pole all-pass filter with central frequency (in Hz)
647 @var{frequency}, and filter-width @var{width}.
648 An all-pass filter changes the audio's frequency to phase relationship
649 without changing its frequency to amplitude relationship.
651 The filter accepts the following options:
658 Set method to specify band-width of filter.
671 Specify the band-width of a filter in width_type units.
677 Merge two or more audio streams into a single multi-channel stream.
679 The filter accepts the following options:
684 Set the number of inputs. Default is 2.
688 If the channel layouts of the inputs are disjoint, and therefore compatible,
689 the channel layout of the output will be set accordingly and the channels
690 will be reordered as necessary. If the channel layouts of the inputs are not
691 disjoint, the output will have all the channels of the first input then all
692 the channels of the second input, in that order, and the channel layout of
693 the output will be the default value corresponding to the total number of
696 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
697 is FC+BL+BR, then the output will be in 5.1, with the channels in the
698 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
699 first input, b1 is the first channel of the second input).
701 On the other hand, if both input are in stereo, the output channels will be
702 in the default order: a1, a2, b1, b2, and the channel layout will be
703 arbitrarily set to 4.0, which may or may not be the expected value.
705 All inputs must have the same sample rate, and format.
707 If inputs do not have the same duration, the output will stop with the
714 Merge two mono files into a stereo stream:
716 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
720 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
722 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
728 Mixes multiple audio inputs into a single output.
730 Note that this filter only supports float samples (the @var{amerge}
731 and @var{pan} audio filters support many formats). If the @var{amix}
732 input has integer samples then @ref{aresample} will be automatically
733 inserted to perform the conversion to float samples.
737 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
739 will mix 3 input audio streams to a single output with the same duration as the
740 first input and a dropout transition time of 3 seconds.
742 It accepts the following parameters:
746 The number of inputs. If unspecified, it defaults to 2.
749 How to determine the end-of-stream.
753 The duration of the longest input. (default)
756 The duration of the shortest input.
759 The duration of the first input.
763 @item dropout_transition
764 The transition time, in seconds, for volume renormalization when an input
765 stream ends. The default value is 2 seconds.
771 Pass the audio source unchanged to the output.
775 Pad the end of an audio stream with silence.
777 This can be used together with @command{ffmpeg} @option{-shortest} to
778 extend audio streams to the same length as the video stream.
780 A description of the accepted options follows.
784 Set silence packet size. Default value is 4096.
787 Set the number of samples of silence to add to the end. After the
788 value is reached, the stream is terminated. This option is mutually
789 exclusive with @option{whole_len}.
792 Set the minimum total number of samples in the output audio stream. If
793 the value is longer than the input audio length, silence is added to
794 the end, until the value is reached. This option is mutually exclusive
795 with @option{pad_len}.
798 If neither the @option{pad_len} nor the @option{whole_len} option is
799 set, the filter will add silence to the end of the input stream
806 Add 1024 samples of silence to the end of the input:
812 Make sure the audio output will contain at least 10000 samples, pad
813 the input with silence if required:
819 Use @command{ffmpeg} to pad the audio input with silence, so that the
820 video stream will always result the shortest and will be converted
821 until the end in the output file when using the @option{shortest}
824 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
829 Add a phasing effect to the input audio.
831 A phaser filter creates series of peaks and troughs in the frequency spectrum.
832 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
834 A description of the accepted parameters follows.
838 Set input gain. Default is 0.4.
841 Set output gain. Default is 0.74
844 Set delay in milliseconds. Default is 3.0.
847 Set decay. Default is 0.4.
850 Set modulation speed in Hz. Default is 0.5.
853 Set modulation type. Default is triangular.
855 It accepts the following values:
865 Resample the input audio to the specified parameters, using the
866 libswresample library. If none are specified then the filter will
867 automatically convert between its input and output.
869 This filter is also able to stretch/squeeze the audio data to make it match
870 the timestamps or to inject silence / cut out audio to make it match the
871 timestamps, do a combination of both or do neither.
873 The filter accepts the syntax
874 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
875 expresses a sample rate and @var{resampler_options} is a list of
876 @var{key}=@var{value} pairs, separated by ":". See the
877 ffmpeg-resampler manual for the complete list of supported options.
883 Resample the input audio to 44100Hz:
889 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
890 samples per second compensation:
896 @section asetnsamples
898 Set the number of samples per each output audio frame.
900 The last output packet may contain a different number of samples, as
901 the filter will flush all the remaining samples when the input audio
904 The filter accepts the following options:
908 @item nb_out_samples, n
909 Set the number of frames per each output audio frame. The number is
910 intended as the number of samples @emph{per each channel}.
911 Default value is 1024.
914 If set to 1, the filter will pad the last audio frame with zeroes, so
915 that the last frame will contain the same number of samples as the
916 previous ones. Default value is 1.
919 For example, to set the number of per-frame samples to 1234 and
920 disable padding for the last frame, use:
922 asetnsamples=n=1234:p=0
927 Set the sample rate without altering the PCM data.
928 This will result in a change of speed and pitch.
930 The filter accepts the following options:
934 Set the output sample rate. Default is 44100 Hz.
939 Show a line containing various information for each input audio frame.
940 The input audio is not modified.
942 The shown line contains a sequence of key/value pairs of the form
943 @var{key}:@var{value}.
945 The following values are shown in the output:
949 The (sequential) number of the input frame, starting from 0.
952 The presentation timestamp of the input frame, in time base units; the time base
953 depends on the filter input pad, and is usually 1/@var{sample_rate}.
956 The presentation timestamp of the input frame in seconds.
959 position of the frame in the input stream, -1 if this information in
960 unavailable and/or meaningless (for example in case of synthetic audio)
969 The sample rate for the audio frame.
972 The number of samples (per channel) in the frame.
975 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
976 audio, the data is treated as if all the planes were concatenated.
978 @item plane_checksums
979 A list of Adler-32 checksums for each data plane.
985 Display time domain statistical information about the audio channels.
986 Statistics are calculated and displayed for each audio channel and,
987 where applicable, an overall figure is also given.
989 It accepts the following option:
992 Short window length in seconds, used for peak and trough RMS measurement.
993 Default is @code{0.05} (50 milliseconds). Allowed range is @code{[0.1 - 10]}.
997 Set metadata injection. All the metadata keys are prefixed with @code{lavfi.astats.X},
998 where @code{X} is channel number starting from 1 or string @code{Overall}. Default is
1001 Available keys for each channel are:
1032 For example full key look like this @code{lavfi.astats.1.DC_offset} or
1033 this @code{lavfi.astats.Overall.Peak_count}.
1035 For description what each key means read bellow.
1038 Set number of frame after which stats are going to be recalculated.
1039 Default is disabled.
1042 A description of each shown parameter follows:
1046 Mean amplitude displacement from zero.
1049 Minimal sample level.
1052 Maximal sample level.
1054 @item Min difference
1055 Minimal difference between two consecutive samples.
1057 @item Max difference
1058 Maximal difference between two consecutive samples.
1060 @item Mean difference
1061 Mean difference between two consecutive samples.
1062 The average of each difference between two consecutive samples.
1066 Standard peak and RMS level measured in dBFS.
1070 Peak and trough values for RMS level measured over a short window.
1073 Standard ratio of peak to RMS level (note: not in dB).
1076 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
1077 (i.e. either @var{Min level} or @var{Max level}).
1080 Number of occasions (not the number of samples) that the signal attained either
1081 @var{Min level} or @var{Max level}.
1084 Overall bit depth of audio. Number of bits used for each sample.
1087 @section astreamsync
1089 Forward two audio streams and control the order the buffers are forwarded.
1091 The filter accepts the following options:
1095 Set the expression deciding which stream should be
1096 forwarded next: if the result is negative, the first stream is forwarded; if
1097 the result is positive or zero, the second stream is forwarded. It can use
1098 the following variables:
1102 number of buffers forwarded so far on each stream
1104 number of samples forwarded so far on each stream
1106 current timestamp of each stream
1109 The default value is @code{t1-t2}, which means to always forward the stream
1110 that has a smaller timestamp.
1113 @subsection Examples
1115 Stress-test @code{amerge} by randomly sending buffers on the wrong
1116 input, while avoiding too much of a desynchronization:
1118 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
1119 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
1125 Synchronize audio data with timestamps by squeezing/stretching it and/or
1126 dropping samples/adding silence when needed.
1128 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1130 It accepts the following parameters:
1134 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1135 by default. When disabled, time gaps are covered with silence.
1138 The minimum difference between timestamps and audio data (in seconds) to trigger
1139 adding/dropping samples. The default value is 0.1. If you get an imperfect
1140 sync with this filter, try setting this parameter to 0.
1143 The maximum compensation in samples per second. Only relevant with compensate=1.
1144 The default value is 500.
1147 Assume that the first PTS should be this value. The time base is 1 / sample
1148 rate. This allows for padding/trimming at the start of the stream. By default,
1149 no assumption is made about the first frame's expected PTS, so no padding or
1150 trimming is done. For example, this could be set to 0 to pad the beginning with
1151 silence if an audio stream starts after the video stream or to trim any samples
1152 with a negative PTS due to encoder delay.
1160 The filter accepts exactly one parameter, the audio tempo. If not
1161 specified then the filter will assume nominal 1.0 tempo. Tempo must
1162 be in the [0.5, 2.0] range.
1164 @subsection Examples
1168 Slow down audio to 80% tempo:
1174 To speed up audio to 125% tempo:
1182 Trim the input so that the output contains one continuous subpart of the input.
1184 It accepts the following parameters:
1187 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1188 sample with the timestamp @var{start} will be the first sample in the output.
1191 Specify time of the first audio sample that will be dropped, i.e. the
1192 audio sample immediately preceding the one with the timestamp @var{end} will be
1193 the last sample in the output.
1196 Same as @var{start}, except this option sets the start timestamp in samples
1200 Same as @var{end}, except this option sets the end timestamp in samples instead
1204 The maximum duration of the output in seconds.
1207 The number of the first sample that should be output.
1210 The number of the first sample that should be dropped.
1213 @option{start}, @option{end}, and @option{duration} are expressed as time
1214 duration specifications; see
1215 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
1217 Note that the first two sets of the start/end options and the @option{duration}
1218 option look at the frame timestamp, while the _sample options simply count the
1219 samples that pass through the filter. So start/end_pts and start/end_sample will
1220 give different results when the timestamps are wrong, inexact or do not start at
1221 zero. Also note that this filter does not modify the timestamps. If you wish
1222 to have the output timestamps start at zero, insert the asetpts filter after the
1225 If multiple start or end options are set, this filter tries to be greedy and
1226 keep all samples that match at least one of the specified constraints. To keep
1227 only the part that matches all the constraints at once, chain multiple atrim
1230 The defaults are such that all the input is kept. So it is possible to set e.g.
1231 just the end values to keep everything before the specified time.
1236 Drop everything except the second minute of input:
1238 ffmpeg -i INPUT -af atrim=60:120
1242 Keep only the first 1000 samples:
1244 ffmpeg -i INPUT -af atrim=end_sample=1000
1251 Apply a two-pole Butterworth band-pass filter with central
1252 frequency @var{frequency}, and (3dB-point) band-width width.
1253 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1254 instead of the default: constant 0dB peak gain.
1255 The filter roll off at 6dB per octave (20dB per decade).
1257 The filter accepts the following options:
1261 Set the filter's central frequency. Default is @code{3000}.
1264 Constant skirt gain if set to 1. Defaults to 0.
1267 Set method to specify band-width of filter.
1280 Specify the band-width of a filter in width_type units.
1285 Apply a two-pole Butterworth band-reject filter with central
1286 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1287 The filter roll off at 6dB per octave (20dB per decade).
1289 The filter accepts the following options:
1293 Set the filter's central frequency. Default is @code{3000}.
1296 Set method to specify band-width of filter.
1309 Specify the band-width of a filter in width_type units.
1314 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1315 shelving filter with a response similar to that of a standard
1316 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1318 The filter accepts the following options:
1322 Give the gain at 0 Hz. Its useful range is about -20
1323 (for a large cut) to +20 (for a large boost).
1324 Beware of clipping when using a positive gain.
1327 Set the filter's central frequency and so can be used
1328 to extend or reduce the frequency range to be boosted or cut.
1329 The default value is @code{100} Hz.
1332 Set method to specify band-width of filter.
1345 Determine how steep is the filter's shelf transition.
1350 Apply a biquad IIR filter with the given coefficients.
1351 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1352 are the numerator and denominator coefficients respectively.
1355 Bauer stereo to binaural transformation, which improves headphone listening of
1356 stereo audio records.
1358 It accepts the following parameters:
1362 Pre-defined crossfeed level.
1366 Default level (fcut=700, feed=50).
1369 Chu Moy circuit (fcut=700, feed=60).
1372 Jan Meier circuit (fcut=650, feed=95).
1377 Cut frequency (in Hz).
1386 Remap input channels to new locations.
1388 It accepts the following parameters:
1390 @item channel_layout
1391 The channel layout of the output stream.
1394 Map channels from input to output. The argument is a '|'-separated list of
1395 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1396 @var{in_channel} form. @var{in_channel} can be either the name of the input
1397 channel (e.g. FL for front left) or its index in the input channel layout.
1398 @var{out_channel} is the name of the output channel or its index in the output
1399 channel layout. If @var{out_channel} is not given then it is implicitly an
1400 index, starting with zero and increasing by one for each mapping.
1403 If no mapping is present, the filter will implicitly map input channels to
1404 output channels, preserving indices.
1406 For example, assuming a 5.1+downmix input MOV file,
1408 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1410 will create an output WAV file tagged as stereo from the downmix channels of
1413 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1415 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:5.1' out.wav
1418 @section channelsplit
1420 Split each channel from an input audio stream into a separate output stream.
1422 It accepts the following parameters:
1424 @item channel_layout
1425 The channel layout of the input stream. The default is "stereo".
1428 For example, assuming a stereo input MP3 file,
1430 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1432 will create an output Matroska file with two audio streams, one containing only
1433 the left channel and the other the right channel.
1435 Split a 5.1 WAV file into per-channel files:
1437 ffmpeg -i in.wav -filter_complex
1438 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1439 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1440 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1445 Add a chorus effect to the audio.
1447 Can make a single vocal sound like a chorus, but can also be applied to instrumentation.
1449 Chorus resembles an echo effect with a short delay, but whereas with echo the delay is
1450 constant, with chorus, it is varied using using sinusoidal or triangular modulation.
1451 The modulation depth defines the range the modulated delay is played before or after
1452 the delay. Hence the delayed sound will sound slower or faster, that is the delayed
1453 sound tuned around the original one, like in a chorus where some vocals are slightly
1456 It accepts the following parameters:
1459 Set input gain. Default is 0.4.
1462 Set output gain. Default is 0.4.
1465 Set delays. A typical delay is around 40ms to 60ms.
1477 @subsection Examples
1483 chorus=0.7:0.9:55:0.4:0.25:2
1489 chorus=0.6:0.9:50|60:0.4|0.32:0.25|0.4:2|1.3
1493 Fuller sounding chorus with three delays:
1495 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
1500 Compress or expand the audio's dynamic range.
1502 It accepts the following parameters:
1508 A list of times in seconds for each channel over which the instantaneous level
1509 of the input signal is averaged to determine its volume. @var{attacks} refers to
1510 increase of volume and @var{decays} refers to decrease of volume. For most
1511 situations, the attack time (response to the audio getting louder) should be
1512 shorter than the decay time, because the human ear is more sensitive to sudden
1513 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1514 a typical value for decay is 0.8 seconds.
1515 If specified number of attacks & decays is lower than number of channels, the last
1516 set attack/decay will be used for all remaining channels.
1519 A list of points for the transfer function, specified in dB relative to the
1520 maximum possible signal amplitude. Each key points list must be defined using
1521 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1522 @code{x0/y0 x1/y1 x2/y2 ....}
1524 The input values must be in strictly increasing order but the transfer function
1525 does not have to be monotonically rising. The point @code{0/0} is assumed but
1526 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1527 function are @code{-70/-70|-60/-20}.
1530 Set the curve radius in dB for all joints. It defaults to 0.01.
1533 Set the additional gain in dB to be applied at all points on the transfer
1534 function. This allows for easy adjustment of the overall gain.
1538 Set an initial volume, in dB, to be assumed for each channel when filtering
1539 starts. This permits the user to supply a nominal level initially, so that, for
1540 example, a very large gain is not applied to initial signal levels before the
1541 companding has begun to operate. A typical value for audio which is initially
1542 quiet is -90 dB. It defaults to 0.
1545 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1546 delayed before being fed to the volume adjuster. Specifying a delay
1547 approximately equal to the attack/decay times allows the filter to effectively
1548 operate in predictive rather than reactive mode. It defaults to 0.
1552 @subsection Examples
1556 Make music with both quiet and loud passages suitable for listening to in a
1559 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1562 Another example for audio with whisper and explosion parts:
1564 compand=0|0:1|1:-90/-900|-70/-70|-30/-9|0/-3:6:0:0:0
1568 A noise gate for when the noise is at a lower level than the signal:
1570 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1574 Here is another noise gate, this time for when the noise is at a higher level
1575 than the signal (making it, in some ways, similar to squelch):
1577 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1582 Apply a DC shift to the audio.
1584 This can be useful to remove a DC offset (caused perhaps by a hardware problem
1585 in the recording chain) from the audio. The effect of a DC offset is reduced
1586 headroom and hence volume. The @ref{astats} filter can be used to determine if
1587 a signal has a DC offset.
1591 Set the DC shift, allowed range is [-1, 1]. It indicates the amount to shift
1595 Optional. It should have a value much less than 1 (e.g. 0.05 or 0.02) and is
1596 used to prevent clipping.
1600 Dynamic Audio Normalizer.
1602 This filter applies a certain amount of gain to the input audio in order
1603 to bring its peak magnitude to a target level (e.g. 0 dBFS). However, in
1604 contrast to more "simple" normalization algorithms, the Dynamic Audio
1605 Normalizer *dynamically* re-adjusts the gain factor to the input audio.
1606 This allows for applying extra gain to the "quiet" sections of the audio
1607 while avoiding distortions or clipping the "loud" sections. In other words:
1608 The Dynamic Audio Normalizer will "even out" the volume of quiet and loud
1609 sections, in the sense that the volume of each section is brought to the
1610 same target level. Note, however, that the Dynamic Audio Normalizer achieves
1611 this goal *without* applying "dynamic range compressing". It will retain 100%
1612 of the dynamic range *within* each section of the audio file.
1616 Set the frame length in milliseconds. In range from 10 to 8000 milliseconds.
1617 Default is 500 milliseconds.
1618 The Dynamic Audio Normalizer processes the input audio in small chunks,
1619 referred to as frames. This is required, because a peak magnitude has no
1620 meaning for just a single sample value. Instead, we need to determine the
1621 peak magnitude for a contiguous sequence of sample values. While a "standard"
1622 normalizer would simply use the peak magnitude of the complete file, the
1623 Dynamic Audio Normalizer determines the peak magnitude individually for each
1624 frame. The length of a frame is specified in milliseconds. By default, the
1625 Dynamic Audio Normalizer uses a frame length of 500 milliseconds, which has
1626 been found to give good results with most files.
1627 Note that the exact frame length, in number of samples, will be determined
1628 automatically, based on the sampling rate of the individual input audio file.
1631 Set the Gaussian filter window size. In range from 3 to 301, must be odd
1632 number. Default is 31.
1633 Probably the most important parameter of the Dynamic Audio Normalizer is the
1634 @code{window size} of the Gaussian smoothing filter. The filter's window size
1635 is specified in frames, centered around the current frame. For the sake of
1636 simplicity, this must be an odd number. Consequently, the default value of 31
1637 takes into account the current frame, as well as the 15 preceding frames and
1638 the 15 subsequent frames. Using a larger window results in a stronger
1639 smoothing effect and thus in less gain variation, i.e. slower gain
1640 adaptation. Conversely, using a smaller window results in a weaker smoothing
1641 effect and thus in more gain variation, i.e. faster gain adaptation.
1642 In other words, the more you increase this value, the more the Dynamic Audio
1643 Normalizer will behave like a "traditional" normalization filter. On the
1644 contrary, the more you decrease this value, the more the Dynamic Audio
1645 Normalizer will behave like a dynamic range compressor.
1648 Set the target peak value. This specifies the highest permissible magnitude
1649 level for the normalized audio input. This filter will try to approach the
1650 target peak magnitude as closely as possible, but at the same time it also
1651 makes sure that the normalized signal will never exceed the peak magnitude.
1652 A frame's maximum local gain factor is imposed directly by the target peak
1653 magnitude. The default value is 0.95 and thus leaves a headroom of 5%*.
1654 It is not recommended to go above this value.
1657 Set the maximum gain factor. In range from 1.0 to 100.0. Default is 10.0.
1658 The Dynamic Audio Normalizer determines the maximum possible (local) gain
1659 factor for each input frame, i.e. the maximum gain factor that does not
1660 result in clipping or distortion. The maximum gain factor is determined by
1661 the frame's highest magnitude sample. However, the Dynamic Audio Normalizer
1662 additionally bounds the frame's maximum gain factor by a predetermined
1663 (global) maximum gain factor. This is done in order to avoid excessive gain
1664 factors in "silent" or almost silent frames. By default, the maximum gain
1665 factor is 10.0, For most inputs the default value should be sufficient and
1666 it usually is not recommended to increase this value. Though, for input
1667 with an extremely low overall volume level, it may be necessary to allow even
1668 higher gain factors. Note, however, that the Dynamic Audio Normalizer does
1669 not simply apply a "hard" threshold (i.e. cut off values above the threshold).
1670 Instead, a "sigmoid" threshold function will be applied. This way, the
1671 gain factors will smoothly approach the threshold value, but never exceed that
1675 Set the target RMS. In range from 0.0 to 1.0. Default is 0.0 - disabled.
1676 By default, the Dynamic Audio Normalizer performs "peak" normalization.
1677 This means that the maximum local gain factor for each frame is defined
1678 (only) by the frame's highest magnitude sample. This way, the samples can
1679 be amplified as much as possible without exceeding the maximum signal
1680 level, i.e. without clipping. Optionally, however, the Dynamic Audio
1681 Normalizer can also take into account the frame's root mean square,
1682 abbreviated RMS. In electrical engineering, the RMS is commonly used to
1683 determine the power of a time-varying signal. It is therefore considered
1684 that the RMS is a better approximation of the "perceived loudness" than
1685 just looking at the signal's peak magnitude. Consequently, by adjusting all
1686 frames to a constant RMS value, a uniform "perceived loudness" can be
1687 established. If a target RMS value has been specified, a frame's local gain
1688 factor is defined as the factor that would result in exactly that RMS value.
1689 Note, however, that the maximum local gain factor is still restricted by the
1690 frame's highest magnitude sample, in order to prevent clipping.
1693 Enable channels coupling. By default is enabled.
1694 By default, the Dynamic Audio Normalizer will amplify all channels by the same
1695 amount. This means the same gain factor will be applied to all channels, i.e.
1696 the maximum possible gain factor is determined by the "loudest" channel.
1697 However, in some recordings, it may happen that the volume of the different
1698 channels is uneven, e.g. one channel may be "quieter" than the other one(s).
1699 In this case, this option can be used to disable the channel coupling. This way,
1700 the gain factor will be determined independently for each channel, depending
1701 only on the individual channel's highest magnitude sample. This allows for
1702 harmonizing the volume of the different channels.
1705 Enable DC bias correction. By default is disabled.
1706 An audio signal (in the time domain) is a sequence of sample values.
1707 In the Dynamic Audio Normalizer these sample values are represented in the
1708 -1.0 to 1.0 range, regardless of the original input format. Normally, the
1709 audio signal, or "waveform", should be centered around the zero point.
1710 That means if we calculate the mean value of all samples in a file, or in a
1711 single frame, then the result should be 0.0 or at least very close to that
1712 value. If, however, there is a significant deviation of the mean value from
1713 0.0, in either positive or negative direction, this is referred to as a
1714 DC bias or DC offset. Since a DC bias is clearly undesirable, the Dynamic
1715 Audio Normalizer provides optional DC bias correction.
1716 With DC bias correction enabled, the Dynamic Audio Normalizer will determine
1717 the mean value, or "DC correction" offset, of each input frame and subtract
1718 that value from all of the frame's sample values which ensures those samples
1719 are centered around 0.0 again. Also, in order to avoid "gaps" at the frame
1720 boundaries, the DC correction offset values will be interpolated smoothly
1721 between neighbouring frames.
1724 Enable alternative boundary mode. By default is disabled.
1725 The Dynamic Audio Normalizer takes into account a certain neighbourhood
1726 around each frame. This includes the preceding frames as well as the
1727 subsequent frames. However, for the "boundary" frames, located at the very
1728 beginning and at the very end of the audio file, not all neighbouring
1729 frames are available. In particular, for the first few frames in the audio
1730 file, the preceding frames are not known. And, similarly, for the last few
1731 frames in the audio file, the subsequent frames are not known. Thus, the
1732 question arises which gain factors should be assumed for the missing frames
1733 in the "boundary" region. The Dynamic Audio Normalizer implements two modes
1734 to deal with this situation. The default boundary mode assumes a gain factor
1735 of exactly 1.0 for the missing frames, resulting in a smooth "fade in" and
1736 "fade out" at the beginning and at the end of the input, respectively.
1739 Set the compress factor. In range from 0.0 to 30.0. Default is 0.0.
1740 By default, the Dynamic Audio Normalizer does not apply "traditional"
1741 compression. This means that signal peaks will not be pruned and thus the
1742 full dynamic range will be retained within each local neighbourhood. However,
1743 in some cases it may be desirable to combine the Dynamic Audio Normalizer's
1744 normalization algorithm with a more "traditional" compression.
1745 For this purpose, the Dynamic Audio Normalizer provides an optional compression
1746 (thresholding) function. If (and only if) the compression feature is enabled,
1747 all input frames will be processed by a soft knee thresholding function prior
1748 to the actual normalization process. Put simply, the thresholding function is
1749 going to prune all samples whose magnitude exceeds a certain threshold value.
1750 However, the Dynamic Audio Normalizer does not simply apply a fixed threshold
1751 value. Instead, the threshold value will be adjusted for each individual
1753 In general, smaller parameters result in stronger compression, and vice versa.
1754 Values below 3.0 are not recommended, because audible distortion may appear.
1759 Make audio easier to listen to on headphones.
1761 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1762 so that when listened to on headphones the stereo image is moved from
1763 inside your head (standard for headphones) to outside and in front of
1764 the listener (standard for speakers).
1770 Apply a two-pole peaking equalisation (EQ) filter. With this
1771 filter, the signal-level at and around a selected frequency can
1772 be increased or decreased, whilst (unlike bandpass and bandreject
1773 filters) that at all other frequencies is unchanged.
1775 In order to produce complex equalisation curves, this filter can
1776 be given several times, each with a different central frequency.
1778 The filter accepts the following options:
1782 Set the filter's central frequency in Hz.
1785 Set method to specify band-width of filter.
1798 Specify the band-width of a filter in width_type units.
1801 Set the required gain or attenuation in dB.
1802 Beware of clipping when using a positive gain.
1805 @subsection Examples
1808 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1810 equalizer=f=1000:width_type=h:width=200:g=-10
1814 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1816 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1821 Apply a flanging effect to the audio.
1823 The filter accepts the following options:
1827 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
1830 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
1833 Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
1837 Set percentage of delayed signal mixed with original. Range from 0 to 100.
1838 Default value is 71.
1841 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
1844 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
1845 Default value is @var{sinusoidal}.
1848 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
1849 Default value is 25.
1852 Set delay-line interpolation, @var{linear} or @var{quadratic}.
1853 Default is @var{linear}.
1858 Apply a high-pass filter with 3dB point frequency.
1859 The filter can be either single-pole, or double-pole (the default).
1860 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1862 The filter accepts the following options:
1866 Set frequency in Hz. Default is 3000.
1869 Set number of poles. Default is 2.
1872 Set method to specify band-width of filter.
1885 Specify the band-width of a filter in width_type units.
1886 Applies only to double-pole filter.
1887 The default is 0.707q and gives a Butterworth response.
1892 Join multiple input streams into one multi-channel stream.
1894 It accepts the following parameters:
1898 The number of input streams. It defaults to 2.
1900 @item channel_layout
1901 The desired output channel layout. It defaults to stereo.
1904 Map channels from inputs to output. The argument is a '|'-separated list of
1905 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1906 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1907 can be either the name of the input channel (e.g. FL for front left) or its
1908 index in the specified input stream. @var{out_channel} is the name of the output
1912 The filter will attempt to guess the mappings when they are not specified
1913 explicitly. It does so by first trying to find an unused matching input channel
1914 and if that fails it picks the first unused input channel.
1916 Join 3 inputs (with properly set channel layouts):
1918 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1921 Build a 5.1 output from 6 single-channel streams:
1923 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1924 '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'
1930 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1932 To enable compilation of this filter you need to configure FFmpeg with
1933 @code{--enable-ladspa}.
1937 Specifies the name of LADSPA plugin library to load. If the environment
1938 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1939 each one of the directories specified by the colon separated list in
1940 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1941 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1942 @file{/usr/lib/ladspa/}.
1945 Specifies the plugin within the library. Some libraries contain only
1946 one plugin, but others contain many of them. If this is not set filter
1947 will list all available plugins within the specified library.
1950 Set the '|' separated list of controls which are zero or more floating point
1951 values that determine the behavior of the loaded plugin (for example delay,
1953 Controls need to be defined using the following syntax:
1954 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1955 @var{valuei} is the value set on the @var{i}-th control.
1956 If @option{controls} is set to @code{help}, all available controls and
1957 their valid ranges are printed.
1959 @item sample_rate, s
1960 Specify the sample rate, default to 44100. Only used if plugin have
1964 Set the number of samples per channel per each output frame, default
1965 is 1024. Only used if plugin have zero inputs.
1968 Set the minimum duration of the sourced audio. See
1969 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
1970 for the accepted syntax.
1971 Note that the resulting duration may be greater than the specified duration,
1972 as the generated audio is always cut at the end of a complete frame.
1973 If not specified, or the expressed duration is negative, the audio is
1974 supposed to be generated forever.
1975 Only used if plugin have zero inputs.
1979 @subsection Examples
1983 List all available plugins within amp (LADSPA example plugin) library:
1989 List all available controls and their valid ranges for @code{vcf_notch}
1990 plugin from @code{VCF} library:
1992 ladspa=f=vcf:p=vcf_notch:c=help
1996 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1999 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
2003 Add reverberation to the audio using TAP-plugins
2004 (Tom's Audio Processing plugins):
2006 ladspa=file=tap_reverb:tap_reverb
2010 Generate white noise, with 0.2 amplitude:
2012 ladspa=file=cmt:noise_source_white:c=c0=.2
2016 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
2017 @code{C* Audio Plugin Suite} (CAPS) library:
2019 ladspa=file=caps:Click:c=c1=20'
2023 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
2025 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
2029 @subsection Commands
2031 This filter supports the following commands:
2034 Modify the @var{N}-th control value.
2036 If the specified value is not valid, it is ignored and prior one is kept.
2041 Apply a low-pass filter with 3dB point frequency.
2042 The filter can be either single-pole or double-pole (the default).
2043 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2045 The filter accepts the following options:
2049 Set frequency in Hz. Default is 500.
2052 Set number of poles. Default is 2.
2055 Set method to specify band-width of filter.
2068 Specify the band-width of a filter in width_type units.
2069 Applies only to double-pole filter.
2070 The default is 0.707q and gives a Butterworth response.
2076 Mix channels with specific gain levels. The filter accepts the output
2077 channel layout followed by a set of channels definitions.
2079 This filter is also designed to efficiently remap the channels of an audio
2082 The filter accepts parameters of the form:
2083 "@var{l}|@var{outdef}|@var{outdef}|..."
2087 output channel layout or number of channels
2090 output channel specification, of the form:
2091 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
2094 output channel to define, either a channel name (FL, FR, etc.) or a channel
2095 number (c0, c1, etc.)
2098 multiplicative coefficient for the channel, 1 leaving the volume unchanged
2101 input channel to use, see out_name for details; it is not possible to mix
2102 named and numbered input channels
2105 If the `=' in a channel specification is replaced by `<', then the gains for
2106 that specification will be renormalized so that the total is 1, thus
2107 avoiding clipping noise.
2109 @subsection Mixing examples
2111 For example, if you want to down-mix from stereo to mono, but with a bigger
2112 factor for the left channel:
2114 pan=1c|c0=0.9*c0+0.1*c1
2117 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
2118 7-channels surround:
2120 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
2123 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
2124 that should be preferred (see "-ac" option) unless you have very specific
2127 @subsection Remapping examples
2129 The channel remapping will be effective if, and only if:
2132 @item gain coefficients are zeroes or ones,
2133 @item only one input per channel output,
2136 If all these conditions are satisfied, the filter will notify the user ("Pure
2137 channel mapping detected"), and use an optimized and lossless method to do the
2140 For example, if you have a 5.1 source and want a stereo audio stream by
2141 dropping the extra channels:
2143 pan="stereo| c0=FL | c1=FR"
2146 Given the same source, you can also switch front left and front right channels
2147 and keep the input channel layout:
2149 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
2152 If the input is a stereo audio stream, you can mute the front left channel (and
2153 still keep the stereo channel layout) with:
2158 Still with a stereo audio stream input, you can copy the right channel in both
2159 front left and right:
2161 pan="stereo| c0=FR | c1=FR"
2166 ReplayGain scanner filter. This filter takes an audio stream as an input and
2167 outputs it unchanged.
2168 At end of filtering it displays @code{track_gain} and @code{track_peak}.
2172 Convert the audio sample format, sample rate and channel layout. It is
2173 not meant to be used directly.
2175 @section sidechaincompress
2177 This filter acts like normal compressor but has the ability to compress
2178 detected signal using second input signal.
2179 It needs two input streams and returns one output stream.
2180 First input stream will be processed depending on second stream signal.
2181 The filtered signal then can be filtered with other filters in later stages of
2182 processing. See @ref{pan} and @ref{amerge} filter.
2184 The filter accepts the following options:
2188 If a signal of second stream raises above this level it will affect the gain
2189 reduction of first stream.
2190 By default is 0.125. Range is between 0.00097563 and 1.
2193 Set a ratio about which the signal is reduced. 1:2 means that if the level
2194 raised 4dB above the threshold, it will be only 2dB above after the reduction.
2195 Default is 2. Range is between 1 and 20.
2198 Amount of milliseconds the signal has to rise above the threshold before gain
2199 reduction starts. Default is 20. Range is between 0.01 and 2000.
2202 Amount of milliseconds the signal has to fall bellow the threshold before
2203 reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
2206 Set the amount by how much signal will be amplified after processing.
2207 Default is 2. Range is from 1 and 64.
2210 Curve the sharp knee around the threshold to enter gain reduction more softly.
2211 Default is 2.82843. Range is between 1 and 8.
2214 Choose if the @code{average} level between all channels of side-chain stream
2215 or the louder(@code{maximum}) channel of side-chain stream affects the
2216 reduction. Default is @code{average}.
2219 Should the exact signal be taken in case of @code{peak} or an RMS one in case
2220 of @code{rms}. Default is @code{rms} which is mainly smoother.
2223 @subsection Examples
2227 Full ffmpeg example taking 2 audio inputs, 1st input to be compressed
2228 depending on the signal of 2nd input and later compressed signal to be
2229 merged with 2nd input:
2231 ffmpeg -i main.flac -i sidechain.flac -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress[compr];[compr][mix]amerge"
2235 @section silencedetect
2237 Detect silence in an audio stream.
2239 This filter logs a message when it detects that the input audio volume is less
2240 or equal to a noise tolerance value for a duration greater or equal to the
2241 minimum detected noise duration.
2243 The printed times and duration are expressed in seconds.
2245 The filter accepts the following options:
2249 Set silence duration until notification (default is 2 seconds).
2252 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
2253 specified value) or amplitude ratio. Default is -60dB, or 0.001.
2256 @subsection Examples
2260 Detect 5 seconds of silence with -50dB noise tolerance:
2262 silencedetect=n=-50dB:d=5
2266 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
2267 tolerance in @file{silence.mp3}:
2269 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
2273 @section silenceremove
2275 Remove silence from the beginning, middle or end of the audio.
2277 The filter accepts the following options:
2281 This value is used to indicate if audio should be trimmed at beginning of
2282 the audio. A value of zero indicates no silence should be trimmed from the
2283 beginning. When specifying a non-zero value, it trims audio up until it
2284 finds non-silence. Normally, when trimming silence from beginning of audio
2285 the @var{start_periods} will be @code{1} but it can be increased to higher
2286 values to trim all audio up to specific count of non-silence periods.
2287 Default value is @code{0}.
2289 @item start_duration
2290 Specify the amount of time that non-silence must be detected before it stops
2291 trimming audio. By increasing the duration, bursts of noises can be treated
2292 as silence and trimmed off. Default value is @code{0}.
2294 @item start_threshold
2295 This indicates what sample value should be treated as silence. For digital
2296 audio, a value of @code{0} may be fine but for audio recorded from analog,
2297 you may wish to increase the value to account for background noise.
2298 Can be specified in dB (in case "dB" is appended to the specified value)
2299 or amplitude ratio. Default value is @code{0}.
2302 Set the count for trimming silence from the end of audio.
2303 To remove silence from the middle of a file, specify a @var{stop_periods}
2304 that is negative. This value is then treated as a positive value and is
2305 used to indicate the effect should restart processing as specified by
2306 @var{start_periods}, making it suitable for removing periods of silence
2307 in the middle of the audio.
2308 Default value is @code{0}.
2311 Specify a duration of silence that must exist before audio is not copied any
2312 more. By specifying a higher duration, silence that is wanted can be left in
2314 Default value is @code{0}.
2316 @item stop_threshold
2317 This is the same as @option{start_threshold} but for trimming silence from
2319 Can be specified in dB (in case "dB" is appended to the specified value)
2320 or amplitude ratio. Default value is @code{0}.
2323 This indicate that @var{stop_duration} length of audio should be left intact
2324 at the beginning of each period of silence.
2325 For example, if you want to remove long pauses between words but do not want
2326 to remove the pauses completely. Default value is @code{0}.
2330 @subsection Examples
2334 The following example shows how this filter can be used to start a recording
2335 that does not contain the delay at the start which usually occurs between
2336 pressing the record button and the start of the performance:
2338 silenceremove=1:5:0.02
2344 Boost or cut treble (upper) frequencies of the audio using a two-pole
2345 shelving filter with a response similar to that of a standard
2346 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
2348 The filter accepts the following options:
2352 Give the gain at whichever is the lower of ~22 kHz and the
2353 Nyquist frequency. Its useful range is about -20 (for a large cut)
2354 to +20 (for a large boost). Beware of clipping when using a positive gain.
2357 Set the filter's central frequency and so can be used
2358 to extend or reduce the frequency range to be boosted or cut.
2359 The default value is @code{3000} Hz.
2362 Set method to specify band-width of filter.
2375 Determine how steep is the filter's shelf transition.
2380 Adjust the input audio volume.
2382 It accepts the following parameters:
2386 Set audio volume expression.
2388 Output values are clipped to the maximum value.
2390 The output audio volume is given by the relation:
2392 @var{output_volume} = @var{volume} * @var{input_volume}
2395 The default value for @var{volume} is "1.0".
2398 This parameter represents the mathematical precision.
2400 It determines which input sample formats will be allowed, which affects the
2401 precision of the volume scaling.
2405 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
2407 32-bit floating-point; this limits input sample format to FLT. (default)
2409 64-bit floating-point; this limits input sample format to DBL.
2413 Choose the behaviour on encountering ReplayGain side data in input frames.
2417 Remove ReplayGain side data, ignoring its contents (the default).
2420 Ignore ReplayGain side data, but leave it in the frame.
2423 Prefer the track gain, if present.
2426 Prefer the album gain, if present.
2429 @item replaygain_preamp
2430 Pre-amplification gain in dB to apply to the selected replaygain gain.
2432 Default value for @var{replaygain_preamp} is 0.0.
2435 Set when the volume expression is evaluated.
2437 It accepts the following values:
2440 only evaluate expression once during the filter initialization, or
2441 when the @samp{volume} command is sent
2444 evaluate expression for each incoming frame
2447 Default value is @samp{once}.
2450 The volume expression can contain the following parameters.
2454 frame number (starting at zero)
2457 @item nb_consumed_samples
2458 number of samples consumed by the filter
2460 number of samples in the current frame
2462 original frame position in the file
2468 PTS at start of stream
2470 time at start of stream
2476 last set volume value
2479 Note that when @option{eval} is set to @samp{once} only the
2480 @var{sample_rate} and @var{tb} variables are available, all other
2481 variables will evaluate to NAN.
2483 @subsection Commands
2485 This filter supports the following commands:
2488 Modify the volume expression.
2489 The command accepts the same syntax of the corresponding option.
2491 If the specified expression is not valid, it is kept at its current
2493 @item replaygain_noclip
2494 Prevent clipping by limiting the gain applied.
2496 Default value for @var{replaygain_noclip} is 1.
2500 @subsection Examples
2504 Halve the input audio volume:
2508 volume=volume=-6.0206dB
2511 In all the above example the named key for @option{volume} can be
2512 omitted, for example like in:
2518 Increase input audio power by 6 decibels using fixed-point precision:
2520 volume=volume=6dB:precision=fixed
2524 Fade volume after time 10 with an annihilation period of 5 seconds:
2526 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
2530 @section volumedetect
2532 Detect the volume of the input video.
2534 The filter has no parameters. The input is not modified. Statistics about
2535 the volume will be printed in the log when the input stream end is reached.
2537 In particular it will show the mean volume (root mean square), maximum
2538 volume (on a per-sample basis), and the beginning of a histogram of the
2539 registered volume values (from the maximum value to a cumulated 1/1000 of
2542 All volumes are in decibels relative to the maximum PCM value.
2544 @subsection Examples
2546 Here is an excerpt of the output:
2548 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2549 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2550 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2551 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2552 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2553 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2554 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2555 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2556 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2562 The mean square energy is approximately -27 dB, or 10^-2.7.
2564 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2566 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2569 In other words, raising the volume by +4 dB does not cause any clipping,
2570 raising it by +5 dB causes clipping for 6 samples, etc.
2572 @c man end AUDIO FILTERS
2574 @chapter Audio Sources
2575 @c man begin AUDIO SOURCES
2577 Below is a description of the currently available audio sources.
2581 Buffer audio frames, and make them available to the filter chain.
2583 This source is mainly intended for a programmatic use, in particular
2584 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2586 It accepts the following parameters:
2590 The timebase which will be used for timestamps of submitted frames. It must be
2591 either a floating-point number or in @var{numerator}/@var{denominator} form.
2594 The sample rate of the incoming audio buffers.
2597 The sample format of the incoming audio buffers.
2598 Either a sample format name or its corresponding integer representation from
2599 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2601 @item channel_layout
2602 The channel layout of the incoming audio buffers.
2603 Either a channel layout name from channel_layout_map in
2604 @file{libavutil/channel_layout.c} or its corresponding integer representation
2605 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2608 The number of channels of the incoming audio buffers.
2609 If both @var{channels} and @var{channel_layout} are specified, then they
2614 @subsection Examples
2617 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2620 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2621 Since the sample format with name "s16p" corresponds to the number
2622 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2625 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2630 Generate an audio signal specified by an expression.
2632 This source accepts in input one or more expressions (one for each
2633 channel), which are evaluated and used to generate a corresponding
2636 This source accepts the following options:
2640 Set the '|'-separated expressions list for each separate channel. In case the
2641 @option{channel_layout} option is not specified, the selected channel layout
2642 depends on the number of provided expressions. Otherwise the last
2643 specified expression is applied to the remaining output channels.
2645 @item channel_layout, c
2646 Set the channel layout. The number of channels in the specified layout
2647 must be equal to the number of specified expressions.
2650 Set the minimum duration of the sourced audio. See
2651 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2652 for the accepted syntax.
2653 Note that the resulting duration may be greater than the specified
2654 duration, as the generated audio is always cut at the end of a
2657 If not specified, or the expressed duration is negative, the audio is
2658 supposed to be generated forever.
2661 Set the number of samples per channel per each output frame,
2664 @item sample_rate, s
2665 Specify the sample rate, default to 44100.
2668 Each expression in @var{exprs} can contain the following constants:
2672 number of the evaluated sample, starting from 0
2675 time of the evaluated sample expressed in seconds, starting from 0
2682 @subsection Examples
2692 Generate a sin signal with frequency of 440 Hz, set sample rate to
2695 aevalsrc="sin(440*2*PI*t):s=8000"
2699 Generate a two channels signal, specify the channel layout (Front
2700 Center + Back Center) explicitly:
2702 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2706 Generate white noise:
2708 aevalsrc="-2+random(0)"
2712 Generate an amplitude modulated signal:
2714 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2718 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2720 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2727 The null audio source, return unprocessed audio frames. It is mainly useful
2728 as a template and to be employed in analysis / debugging tools, or as
2729 the source for filters which ignore the input data (for example the sox
2732 This source accepts the following options:
2736 @item channel_layout, cl
2738 Specifies the channel layout, and can be either an integer or a string
2739 representing a channel layout. The default value of @var{channel_layout}
2742 Check the channel_layout_map definition in
2743 @file{libavutil/channel_layout.c} for the mapping between strings and
2744 channel layout values.
2746 @item sample_rate, r
2747 Specifies the sample rate, and defaults to 44100.
2750 Set the number of samples per requested frames.
2754 @subsection Examples
2758 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2760 anullsrc=r=48000:cl=4
2764 Do the same operation with a more obvious syntax:
2766 anullsrc=r=48000:cl=mono
2770 All the parameters need to be explicitly defined.
2774 Synthesize a voice utterance using the libflite library.
2776 To enable compilation of this filter you need to configure FFmpeg with
2777 @code{--enable-libflite}.
2779 Note that the flite library is not thread-safe.
2781 The filter accepts the following options:
2786 If set to 1, list the names of the available voices and exit
2787 immediately. Default value is 0.
2790 Set the maximum number of samples per frame. Default value is 512.
2793 Set the filename containing the text to speak.
2796 Set the text to speak.
2799 Set the voice to use for the speech synthesis. Default value is
2800 @code{kal}. See also the @var{list_voices} option.
2803 @subsection Examples
2807 Read from file @file{speech.txt}, and synthesize the text using the
2808 standard flite voice:
2810 flite=textfile=speech.txt
2814 Read the specified text selecting the @code{slt} voice:
2816 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2820 Input text to ffmpeg:
2822 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2826 Make @file{ffplay} speak the specified text, using @code{flite} and
2827 the @code{lavfi} device:
2829 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2833 For more information about libflite, check:
2834 @url{http://www.speech.cs.cmu.edu/flite/}
2838 Generate an audio signal made of a sine wave with amplitude 1/8.
2840 The audio signal is bit-exact.
2842 The filter accepts the following options:
2847 Set the carrier frequency. Default is 440 Hz.
2849 @item beep_factor, b
2850 Enable a periodic beep every second with frequency @var{beep_factor} times
2851 the carrier frequency. Default is 0, meaning the beep is disabled.
2853 @item sample_rate, r
2854 Specify the sample rate, default is 44100.
2857 Specify the duration of the generated audio stream.
2859 @item samples_per_frame
2860 Set the number of samples per output frame, default is 1024.
2863 @subsection Examples
2868 Generate a simple 440 Hz sine wave:
2874 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2878 sine=frequency=220:beep_factor=4:duration=5
2883 @c man end AUDIO SOURCES
2885 @chapter Audio Sinks
2886 @c man begin AUDIO SINKS
2888 Below is a description of the currently available audio sinks.
2890 @section abuffersink
2892 Buffer audio frames, and make them available to the end of filter chain.
2894 This sink is mainly intended for programmatic use, in particular
2895 through the interface defined in @file{libavfilter/buffersink.h}
2896 or the options system.
2898 It accepts a pointer to an AVABufferSinkContext structure, which
2899 defines the incoming buffers' formats, to be passed as the opaque
2900 parameter to @code{avfilter_init_filter} for initialization.
2903 Null audio sink; do absolutely nothing with the input audio. It is
2904 mainly useful as a template and for use in analysis / debugging
2907 @c man end AUDIO SINKS
2909 @chapter Video Filters
2910 @c man begin VIDEO FILTERS
2912 When you configure your FFmpeg build, you can disable any of the
2913 existing filters using @code{--disable-filters}.
2914 The configure output will show the video filters included in your
2917 Below is a description of the currently available video filters.
2919 @section alphaextract
2921 Extract the alpha component from the input as a grayscale video. This
2922 is especially useful with the @var{alphamerge} filter.
2926 Add or replace the alpha component of the primary input with the
2927 grayscale value of a second input. This is intended for use with
2928 @var{alphaextract} to allow the transmission or storage of frame
2929 sequences that have alpha in a format that doesn't support an alpha
2932 For example, to reconstruct full frames from a normal YUV-encoded video
2933 and a separate video created with @var{alphaextract}, you might use:
2935 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2938 Since this filter is designed for reconstruction, it operates on frame
2939 sequences without considering timestamps, and terminates when either
2940 input reaches end of stream. This will cause problems if your encoding
2941 pipeline drops frames. If you're trying to apply an image as an
2942 overlay to a video stream, consider the @var{overlay} filter instead.
2946 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2947 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2948 Substation Alpha) subtitles files.
2950 This filter accepts the following option in addition to the common options from
2951 the @ref{subtitles} filter:
2955 Set the shaping engine
2957 Available values are:
2960 The default libass shaping engine, which is the best available.
2962 Fast, font-agnostic shaper that can do only substitutions
2964 Slower shaper using OpenType for substitutions and positioning
2967 The default is @code{auto}.
2971 Apply an Adaptive Temporal Averaging Denoiser to the video input.
2973 The filter accepts the following options:
2977 Set threshold A for 1st plane. Default is 0.02.
2978 Valid range is 0 to 0.3.
2981 Set threshold B for 1st plane. Default is 0.04.
2982 Valid range is 0 to 5.
2985 Set threshold A for 2nd plane. Default is 0.02.
2986 Valid range is 0 to 0.3.
2989 Set threshold B for 2nd plane. Default is 0.04.
2990 Valid range is 0 to 5.
2993 Set threshold A for 3rd plane. Default is 0.02.
2994 Valid range is 0 to 0.3.
2997 Set threshold B for 3rd plane. Default is 0.04.
2998 Valid range is 0 to 5.
3000 Threshold A is designed to react on abrupt changes in the input signal and
3001 threshold B is designed to react on continuous changes in the input signal.
3004 Set number of frames filter will use for averaging. Default is 33. Must be odd
3005 number in range [5, 129].
3010 Compute the bounding box for the non-black pixels in the input frame
3013 This filter computes the bounding box containing all the pixels with a
3014 luminance value greater than the minimum allowed value.
3015 The parameters describing the bounding box are printed on the filter
3018 The filter accepts the following option:
3022 Set the minimal luminance value. Default is @code{16}.
3025 @section blackdetect
3027 Detect video intervals that are (almost) completely black. Can be
3028 useful to detect chapter transitions, commercials, or invalid
3029 recordings. Output lines contains the time for the start, end and
3030 duration of the detected black interval expressed in seconds.
3032 In order to display the output lines, you need to set the loglevel at
3033 least to the AV_LOG_INFO value.
3035 The filter accepts the following options:
3038 @item black_min_duration, d
3039 Set the minimum detected black duration expressed in seconds. It must
3040 be a non-negative floating point number.
3042 Default value is 2.0.
3044 @item picture_black_ratio_th, pic_th
3045 Set the threshold for considering a picture "black".
3046 Express the minimum value for the ratio:
3048 @var{nb_black_pixels} / @var{nb_pixels}
3051 for which a picture is considered black.
3052 Default value is 0.98.
3054 @item pixel_black_th, pix_th
3055 Set the threshold for considering a pixel "black".
3057 The threshold expresses the maximum pixel luminance value for which a
3058 pixel is considered "black". The provided value is scaled according to
3059 the following equation:
3061 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
3064 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
3065 the input video format, the range is [0-255] for YUV full-range
3066 formats and [16-235] for YUV non full-range formats.
3068 Default value is 0.10.
3071 The following example sets the maximum pixel threshold to the minimum
3072 value, and detects only black intervals of 2 or more seconds:
3074 blackdetect=d=2:pix_th=0.00
3079 Detect frames that are (almost) completely black. Can be useful to
3080 detect chapter transitions or commercials. Output lines consist of
3081 the frame number of the detected frame, the percentage of blackness,
3082 the position in the file if known or -1 and the timestamp in seconds.
3084 In order to display the output lines, you need to set the loglevel at
3085 least to the AV_LOG_INFO value.
3087 It accepts the following parameters:
3092 The percentage of the pixels that have to be below the threshold; it defaults to
3095 @item threshold, thresh
3096 The threshold below which a pixel value is considered black; it defaults to
3101 @section blend, tblend
3103 Blend two video frames into each other.
3105 The @code{blend} filter takes two input streams and outputs one
3106 stream, the first input is the "top" layer and second input is
3107 "bottom" layer. Output terminates when shortest input terminates.
3109 The @code{tblend} (time blend) filter takes two consecutive frames
3110 from one single stream, and outputs the result obtained by blending
3111 the new frame on top of the old frame.
3113 A description of the accepted options follows.
3121 Set blend mode for specific pixel component or all pixel components in case
3122 of @var{all_mode}. Default value is @code{normal}.
3124 Available values for component modes are:
3161 Set blend opacity for specific pixel component or all pixel components in case
3162 of @var{all_opacity}. Only used in combination with pixel component blend modes.
3169 Set blend expression for specific pixel component or all pixel components in case
3170 of @var{all_expr}. Note that related mode options will be ignored if those are set.
3172 The expressions can use the following variables:
3176 The sequential number of the filtered frame, starting from @code{0}.
3180 the coordinates of the current sample
3184 the width and height of currently filtered plane
3188 Width and height scale depending on the currently filtered plane. It is the
3189 ratio between the corresponding luma plane number of pixels and the current
3190 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
3191 @code{0.5,0.5} for chroma planes.
3194 Time of the current frame, expressed in seconds.
3197 Value of pixel component at current location for first video frame (top layer).
3200 Value of pixel component at current location for second video frame (bottom layer).
3204 Force termination when the shortest input terminates. Default is
3205 @code{0}. This option is only defined for the @code{blend} filter.
3208 Continue applying the last bottom frame after the end of the stream. A value of
3209 @code{0} disable the filter after the last frame of the bottom layer is reached.
3210 Default is @code{1}. This option is only defined for the @code{blend} filter.
3213 @subsection Examples
3217 Apply transition from bottom layer to top layer in first 10 seconds:
3219 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
3223 Apply 1x1 checkerboard effect:
3225 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
3229 Apply uncover left effect:
3231 blend=all_expr='if(gte(N*SW+X,W),A,B)'
3235 Apply uncover down effect:
3237 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
3241 Apply uncover up-left effect:
3243 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
3247 Display differences between the current and the previous frame:
3249 tblend=all_mode=difference128
3255 Apply a boxblur algorithm to the input video.
3257 It accepts the following parameters:
3261 @item luma_radius, lr
3262 @item luma_power, lp
3263 @item chroma_radius, cr
3264 @item chroma_power, cp
3265 @item alpha_radius, ar
3266 @item alpha_power, ap
3270 A description of the accepted options follows.
3273 @item luma_radius, lr
3274 @item chroma_radius, cr
3275 @item alpha_radius, ar
3276 Set an expression for the box radius in pixels used for blurring the
3277 corresponding input plane.
3279 The radius value must be a non-negative number, and must not be
3280 greater than the value of the expression @code{min(w,h)/2} for the
3281 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
3284 Default value for @option{luma_radius} is "2". If not specified,
3285 @option{chroma_radius} and @option{alpha_radius} default to the
3286 corresponding value set for @option{luma_radius}.
3288 The expressions can contain the following constants:
3292 The input width and height in pixels.
3296 The input chroma image width and height in pixels.
3300 The horizontal and vertical chroma subsample values. For example, for the
3301 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
3304 @item luma_power, lp
3305 @item chroma_power, cp
3306 @item alpha_power, ap
3307 Specify how many times the boxblur filter is applied to the
3308 corresponding plane.
3310 Default value for @option{luma_power} is 2. If not specified,
3311 @option{chroma_power} and @option{alpha_power} default to the
3312 corresponding value set for @option{luma_power}.
3314 A value of 0 will disable the effect.
3317 @subsection Examples
3321 Apply a boxblur filter with the luma, chroma, and alpha radii
3324 boxblur=luma_radius=2:luma_power=1
3329 Set the luma radius to 2, and alpha and chroma radius to 0:
3331 boxblur=2:1:cr=0:ar=0
3335 Set the luma and chroma radii to a fraction of the video dimension:
3337 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
3343 Visualize information exported by some codecs.
3345 Some codecs can export information through frames using side-data or other
3346 means. For example, some MPEG based codecs export motion vectors through the
3347 @var{export_mvs} flag in the codec @option{flags2} option.
3349 The filter accepts the following option:
3353 Set motion vectors to visualize.
3355 Available flags for @var{mv} are:
3359 forward predicted MVs of P-frames
3361 forward predicted MVs of B-frames
3363 backward predicted MVs of B-frames
3367 @subsection Examples
3371 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
3373 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
3377 @section colorbalance
3378 Modify intensity of primary colors (red, green and blue) of input frames.
3380 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
3381 regions for the red-cyan, green-magenta or blue-yellow balance.
3383 A positive adjustment value shifts the balance towards the primary color, a negative
3384 value towards the complementary color.
3386 The filter accepts the following options:
3392 Adjust red, green and blue shadows (darkest pixels).
3397 Adjust red, green and blue midtones (medium pixels).
3402 Adjust red, green and blue highlights (brightest pixels).
3404 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
3407 @subsection Examples
3411 Add red color cast to shadows:
3418 RGB colorspace color keying.
3420 The filter accepts the following options:
3424 The color which will be replaced with transparency.
3427 Similarity percentage with the key color.
3429 0.01 matches only the exact key color, while 1.0 matches everything.
3434 0.0 makes pixels either fully transparent, or not transparent at all.
3436 Higher values result in semi-transparent pixels, with a higher transparency
3437 the more similar the pixels color is to the key color.
3440 @subsection Examples
3444 Make every green pixel in the input image transparent:
3446 ffmpeg -i input.png -vf colorkey=green out.png
3450 Overlay a greenscreen-video on top of a static background image.
3452 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
3456 @section colorlevels
3458 Adjust video input frames using levels.
3460 The filter accepts the following options:
3467 Adjust red, green, blue and alpha input black point.
3468 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
3474 Adjust red, green, blue and alpha input white point.
3475 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
3477 Input levels are used to lighten highlights (bright tones), darken shadows
3478 (dark tones), change the balance of bright and dark tones.
3484 Adjust red, green, blue and alpha output black point.
3485 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
3491 Adjust red, green, blue and alpha output white point.
3492 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
3494 Output levels allows manual selection of a constrained output level range.
3497 @subsection Examples
3501 Make video output darker:
3503 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
3509 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
3513 Make video output lighter:
3515 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
3519 Increase brightness:
3521 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
3525 @section colorchannelmixer
3527 Adjust video input frames by re-mixing color channels.
3529 This filter modifies a color channel by adding the values associated to
3530 the other channels of the same pixels. For example if the value to
3531 modify is red, the output value will be:
3533 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
3536 The filter accepts the following options:
3543 Adjust contribution of input red, green, blue and alpha channels for output red channel.
3544 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
3550 Adjust contribution of input red, green, blue and alpha channels for output green channel.
3551 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
3557 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
3558 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
3564 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
3565 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
3567 Allowed ranges for options are @code{[-2.0, 2.0]}.
3570 @subsection Examples
3574 Convert source to grayscale:
3576 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
3579 Simulate sepia tones:
3581 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
3585 @section colormatrix
3587 Convert color matrix.
3589 The filter accepts the following options:
3594 Specify the source and destination color matrix. Both values must be
3597 The accepted values are:
3613 For example to convert from BT.601 to SMPTE-240M, use the command:
3615 colormatrix=bt601:smpte240m
3620 Copy the input source unchanged to the output. This is mainly useful for
3625 Crop the input video to given dimensions.
3627 It accepts the following parameters:
3631 The width of the output video. It defaults to @code{iw}.
3632 This expression is evaluated only once during the filter
3633 configuration, or when the @samp{w} or @samp{out_w} command is sent.
3636 The height of the output video. It defaults to @code{ih}.
3637 This expression is evaluated only once during the filter
3638 configuration, or when the @samp{h} or @samp{out_h} command is sent.
3641 The horizontal position, in the input video, of the left edge of the output
3642 video. It defaults to @code{(in_w-out_w)/2}.
3643 This expression is evaluated per-frame.
3646 The vertical position, in the input video, of the top edge of the output video.
3647 It defaults to @code{(in_h-out_h)/2}.
3648 This expression is evaluated per-frame.
3651 If set to 1 will force the output display aspect ratio
3652 to be the same of the input, by changing the output sample aspect
3653 ratio. It defaults to 0.
3656 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
3657 expressions containing the following constants:
3662 The computed values for @var{x} and @var{y}. They are evaluated for
3667 The input width and height.
3671 These are the same as @var{in_w} and @var{in_h}.
3675 The output (cropped) width and height.
3679 These are the same as @var{out_w} and @var{out_h}.
3682 same as @var{iw} / @var{ih}
3685 input sample aspect ratio
3688 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
3692 horizontal and vertical chroma subsample values. For example for the
3693 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3696 The number of the input frame, starting from 0.
3699 the position in the file of the input frame, NAN if unknown
3702 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
3706 The expression for @var{out_w} may depend on the value of @var{out_h},
3707 and the expression for @var{out_h} may depend on @var{out_w}, but they
3708 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
3709 evaluated after @var{out_w} and @var{out_h}.
3711 The @var{x} and @var{y} parameters specify the expressions for the
3712 position of the top-left corner of the output (non-cropped) area. They
3713 are evaluated for each frame. If the evaluated value is not valid, it
3714 is approximated to the nearest valid value.
3716 The expression for @var{x} may depend on @var{y}, and the expression
3717 for @var{y} may depend on @var{x}.
3719 @subsection Examples
3723 Crop area with size 100x100 at position (12,34).
3728 Using named options, the example above becomes:
3730 crop=w=100:h=100:x=12:y=34
3734 Crop the central input area with size 100x100:
3740 Crop the central input area with size 2/3 of the input video:
3742 crop=2/3*in_w:2/3*in_h
3746 Crop the input video central square:
3753 Delimit the rectangle with the top-left corner placed at position
3754 100:100 and the right-bottom corner corresponding to the right-bottom
3755 corner of the input image.
3757 crop=in_w-100:in_h-100:100:100
3761 Crop 10 pixels from the left and right borders, and 20 pixels from
3762 the top and bottom borders
3764 crop=in_w-2*10:in_h-2*20
3768 Keep only the bottom right quarter of the input image:
3770 crop=in_w/2:in_h/2:in_w/2:in_h/2
3774 Crop height for getting Greek harmony:
3776 crop=in_w:1/PHI*in_w
3780 Apply trembling effect:
3782 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)
3786 Apply erratic camera effect depending on timestamp:
3788 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)"
3792 Set x depending on the value of y:
3794 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3798 @subsection Commands
3800 This filter supports the following commands:
3806 Set width/height of the output video and the horizontal/vertical position
3808 The command accepts the same syntax of the corresponding option.
3810 If the specified expression is not valid, it is kept at its current
3816 Auto-detect the crop size.
3818 It calculates the necessary cropping parameters and prints the
3819 recommended parameters via the logging system. The detected dimensions
3820 correspond to the non-black area of the input video.
3822 It accepts the following parameters:
3827 Set higher black value threshold, which can be optionally specified
3828 from nothing (0) to everything (255 for 8bit based formats). An intensity
3829 value greater to the set value is considered non-black. It defaults to 24.
3830 You can also specify a value between 0.0 and 1.0 which will be scaled depending
3831 on the bitdepth of the pixel format.
3834 The value which the width/height should be divisible by. It defaults to
3835 16. The offset is automatically adjusted to center the video. Use 2 to
3836 get only even dimensions (needed for 4:2:2 video). 16 is best when
3837 encoding to most video codecs.
3839 @item reset_count, reset
3840 Set the counter that determines after how many frames cropdetect will
3841 reset the previously detected largest video area and start over to
3842 detect the current optimal crop area. Default value is 0.
3844 This can be useful when channel logos distort the video area. 0
3845 indicates 'never reset', and returns the largest area encountered during
3852 Apply color adjustments using curves.
3854 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3855 component (red, green and blue) has its values defined by @var{N} key points
3856 tied from each other using a smooth curve. The x-axis represents the pixel
3857 values from the input frame, and the y-axis the new pixel values to be set for
3860 By default, a component curve is defined by the two points @var{(0;0)} and
3861 @var{(1;1)}. This creates a straight line where each original pixel value is
3862 "adjusted" to its own value, which means no change to the image.
3864 The filter allows you to redefine these two points and add some more. A new
3865 curve (using a natural cubic spline interpolation) will be define to pass
3866 smoothly through all these new coordinates. The new defined points needs to be
3867 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3868 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3869 the vector spaces, the values will be clipped accordingly.
3871 If there is no key point defined in @code{x=0}, the filter will automatically
3872 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3873 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3875 The filter accepts the following options:
3879 Select one of the available color presets. This option can be used in addition
3880 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3881 options takes priority on the preset values.
3882 Available presets are:
3885 @item color_negative
3888 @item increase_contrast
3890 @item linear_contrast
3891 @item medium_contrast
3893 @item strong_contrast
3896 Default is @code{none}.
3898 Set the master key points. These points will define a second pass mapping. It
3899 is sometimes called a "luminance" or "value" mapping. It can be used with
3900 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3901 post-processing LUT.
3903 Set the key points for the red component.
3905 Set the key points for the green component.
3907 Set the key points for the blue component.
3909 Set the key points for all components (not including master).
3910 Can be used in addition to the other key points component
3911 options. In this case, the unset component(s) will fallback on this
3912 @option{all} setting.
3914 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3917 To avoid some filtergraph syntax conflicts, each key points list need to be
3918 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3920 @subsection Examples
3924 Increase slightly the middle level of blue:
3926 curves=blue='0.5/0.58'
3932 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3934 Here we obtain the following coordinates for each components:
3937 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3939 @code{(0;0) (0.50;0.48) (1;1)}
3941 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3945 The previous example can also be achieved with the associated built-in preset:
3947 curves=preset=vintage
3957 Use a Photoshop preset and redefine the points of the green component:
3959 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3965 Denoise frames using 2D DCT (frequency domain filtering).
3967 This filter is not designed for real time.
3969 The filter accepts the following options:
3973 Set the noise sigma constant.
3975 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3976 coefficient (absolute value) below this threshold with be dropped.
3978 If you need a more advanced filtering, see @option{expr}.
3980 Default is @code{0}.
3983 Set number overlapping pixels for each block. Since the filter can be slow, you
3984 may want to reduce this value, at the cost of a less effective filter and the
3985 risk of various artefacts.
3987 If the overlapping value doesn't permit processing the whole input width or
3988 height, a warning will be displayed and according borders won't be denoised.
3990 Default value is @var{blocksize}-1, which is the best possible setting.
3993 Set the coefficient factor expression.
3995 For each coefficient of a DCT block, this expression will be evaluated as a
3996 multiplier value for the coefficient.
3998 If this is option is set, the @option{sigma} option will be ignored.
4000 The absolute value of the coefficient can be accessed through the @var{c}
4004 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
4005 @var{blocksize}, which is the width and height of the processed blocks.
4007 The default value is @var{3} (8x8) and can be raised to @var{4} for a
4008 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
4009 on the speed processing. Also, a larger block size does not necessarily means a
4013 @subsection Examples
4015 Apply a denoise with a @option{sigma} of @code{4.5}:
4020 The same operation can be achieved using the expression system:
4022 dctdnoiz=e='gte(c, 4.5*3)'
4025 Violent denoise using a block size of @code{16x16}:
4032 Remove banding artifacts from input video.
4033 It works by replacing banded pixels with average value of referenced pixels.
4035 The filter accepts the following options:
4042 Set banding detection threshold for each plane. Default is 0.02.
4043 Valid range is 0.00003 to 0.5.
4044 If difference between current pixel and reference pixel is less than threshold,
4045 it will be considered as banded.
4048 Banding detection range in pixels. Default is 16. If positive, random number
4049 in range 0 to set value will be used. If negative, exact absolute value
4051 The range defines square of four pixels around current pixel.
4054 Set direction in radians from which four pixel will be compared. If positive,
4055 random direction from 0 to set direction will be picked. If negative, exact of
4056 absolute value will be picked. For example direction 0, -PI or -2*PI radians
4057 will pick only pixels on same row and -PI/2 will pick only pixels on same
4061 If enabled, current pixel is compared with average value of all four
4062 surrounding pixels. The default is enabled. If disabled current pixel is
4063 compared with all four surrounding pixels. The pixel is considered banded
4064 if only all four differences with surrounding pixels are less than threshold.
4070 Drop duplicated frames at regular intervals.
4072 The filter accepts the following options:
4076 Set the number of frames from which one will be dropped. Setting this to
4077 @var{N} means one frame in every batch of @var{N} frames will be dropped.
4078 Default is @code{5}.
4081 Set the threshold for duplicate detection. If the difference metric for a frame
4082 is less than or equal to this value, then it is declared as duplicate. Default
4086 Set scene change threshold. Default is @code{15}.
4090 Set the size of the x and y-axis blocks used during metric calculations.
4091 Larger blocks give better noise suppression, but also give worse detection of
4092 small movements. Must be a power of two. Default is @code{32}.
4095 Mark main input as a pre-processed input and activate clean source input
4096 stream. This allows the input to be pre-processed with various filters to help
4097 the metrics calculation while keeping the frame selection lossless. When set to
4098 @code{1}, the first stream is for the pre-processed input, and the second
4099 stream is the clean source from where the kept frames are chosen. Default is
4103 Set whether or not chroma is considered in the metric calculations. Default is
4109 Apply deflate effect to the video.
4111 This filter replaces the pixel by the local(3x3) average by taking into account
4112 only values lower than the pixel.
4114 It accepts the following options:
4121 Allows to limit the maximum change for each plane, default is 65535.
4122 If 0, plane will remain unchanged.
4127 Remove judder produced by partially interlaced telecined content.
4129 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
4130 source was partially telecined content then the output of @code{pullup,dejudder}
4131 will have a variable frame rate. May change the recorded frame rate of the
4132 container. Aside from that change, this filter will not affect constant frame
4135 The option available in this filter is:
4139 Specify the length of the window over which the judder repeats.
4141 Accepts any integer greater than 1. Useful values are:
4145 If the original was telecined from 24 to 30 fps (Film to NTSC).
4148 If the original was telecined from 25 to 30 fps (PAL to NTSC).
4151 If a mixture of the two.
4154 The default is @samp{4}.
4159 Suppress a TV station logo by a simple interpolation of the surrounding
4160 pixels. Just set a rectangle covering the logo and watch it disappear
4161 (and sometimes something even uglier appear - your mileage may vary).
4163 It accepts the following parameters:
4168 Specify the top left corner coordinates of the logo. They must be
4173 Specify the width and height of the logo to clear. They must be
4177 Specify the thickness of the fuzzy edge of the rectangle (added to
4178 @var{w} and @var{h}). The default value is 4.
4181 When set to 1, a green rectangle is drawn on the screen to simplify
4182 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
4183 The default value is 0.
4185 The rectangle is drawn on the outermost pixels which will be (partly)
4186 replaced with interpolated values. The values of the next pixels
4187 immediately outside this rectangle in each direction will be used to
4188 compute the interpolated pixel values inside the rectangle.
4192 @subsection Examples
4196 Set a rectangle covering the area with top left corner coordinates 0,0
4197 and size 100x77, and a band of size 10:
4199 delogo=x=0:y=0:w=100:h=77:band=10
4206 Attempt to fix small changes in horizontal and/or vertical shift. This
4207 filter helps remove camera shake from hand-holding a camera, bumping a
4208 tripod, moving on a vehicle, etc.
4210 The filter accepts the following options:
4218 Specify a rectangular area where to limit the search for motion
4220 If desired the search for motion vectors can be limited to a
4221 rectangular area of the frame defined by its top left corner, width
4222 and height. These parameters have the same meaning as the drawbox
4223 filter which can be used to visualise the position of the bounding
4226 This is useful when simultaneous movement of subjects within the frame
4227 might be confused for camera motion by the motion vector search.
4229 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
4230 then the full frame is used. This allows later options to be set
4231 without specifying the bounding box for the motion vector search.
4233 Default - search the whole frame.
4237 Specify the maximum extent of movement in x and y directions in the
4238 range 0-64 pixels. Default 16.
4241 Specify how to generate pixels to fill blanks at the edge of the
4242 frame. Available values are:
4245 Fill zeroes at blank locations
4247 Original image at blank locations
4249 Extruded edge value at blank locations
4251 Mirrored edge at blank locations
4253 Default value is @samp{mirror}.
4256 Specify the blocksize to use for motion search. Range 4-128 pixels,
4260 Specify the contrast threshold for blocks. Only blocks with more than
4261 the specified contrast (difference between darkest and lightest
4262 pixels) will be considered. Range 1-255, default 125.
4265 Specify the search strategy. Available values are:
4268 Set exhaustive search
4270 Set less exhaustive search.
4272 Default value is @samp{exhaustive}.
4275 If set then a detailed log of the motion search is written to the
4279 If set to 1, specify using OpenCL capabilities, only available if
4280 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
4286 Apply an exact inverse of the telecine operation. It requires a predefined
4287 pattern specified using the pattern option which must be the same as that passed
4288 to the telecine filter.
4290 This filter accepts the following options:
4299 The default value is @code{top}.
4303 A string of numbers representing the pulldown pattern you wish to apply.
4304 The default value is @code{23}.
4307 A number representing position of the first frame with respect to the telecine
4308 pattern. This is to be used if the stream is cut. The default value is @code{0}.
4313 Apply dilation effect to the video.
4315 This filter replaces the pixel by the local(3x3) maximum.
4317 It accepts the following options:
4324 Allows to limit the maximum change for each plane, default is 65535.
4325 If 0, plane will remain unchanged.
4328 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
4331 Flags to local 3x3 coordinates maps like this:
4340 Draw a colored box on the input image.
4342 It accepts the following parameters:
4347 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
4351 The expressions which specify the width and height of the box; if 0 they are interpreted as
4352 the input width and height. It defaults to 0.
4355 Specify the color of the box to write. For the general syntax of this option,
4356 check the "Color" section in the ffmpeg-utils manual. If the special
4357 value @code{invert} is used, the box edge color is the same as the
4358 video with inverted luma.
4361 The expression which sets the thickness of the box edge. Default value is @code{3}.
4363 See below for the list of accepted constants.
4366 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
4367 following constants:
4371 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
4375 horizontal and vertical chroma subsample values. For example for the
4376 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4380 The input width and height.
4383 The input sample aspect ratio.
4387 The x and y offset coordinates where the box is drawn.
4391 The width and height of the drawn box.
4394 The thickness of the drawn box.
4396 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
4397 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
4401 @subsection Examples
4405 Draw a black box around the edge of the input image:
4411 Draw a box with color red and an opacity of 50%:
4413 drawbox=10:20:200:60:red@@0.5
4416 The previous example can be specified as:
4418 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
4422 Fill the box with pink color:
4424 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
4428 Draw a 2-pixel red 2.40:1 mask:
4430 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
4434 @section drawgraph, adrawgraph
4436 Draw a graph using input video or audio metadata.
4438 It accepts the following parameters:
4442 Set 1st frame metadata key from which metadata values will be used to draw a graph.
4445 Set 1st foreground color expression.
4448 Set 2nd frame metadata key from which metadata values will be used to draw a graph.
4451 Set 2nd foreground color expression.
4454 Set 3rd frame metadata key from which metadata values will be used to draw a graph.
4457 Set 3rd foreground color expression.
4460 Set 4th frame metadata key from which metadata values will be used to draw a graph.
4463 Set 4th foreground color expression.
4466 Set minimal value of metadata value.
4469 Set maximal value of metadata value.
4472 Set graph background color. Default is white.
4477 Available values for mode is:
4484 Default is @code{line}.
4489 Available values for slide is:
4492 Draw new frame when right border is reached.
4495 Replace old columns with new ones.
4498 Scroll from right to left.
4501 Default is @code{frame}.
4504 Set size of graph video. For the syntax of this option, check the
4505 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
4506 The default value is @code{900x256}.
4508 The foreground color expressions can use the following variables:
4511 Minimal value of metadata value.
4514 Maximal value of metadata value.
4517 Current metadata key value.
4520 The color is defined as 0xAABBGGRR.
4523 Example using metadata from @ref{signalstats} filter:
4525 signalstats,drawgraph=lavfi.signalstats.YAVG:min=0:max=255
4528 Example using metadata from @ref{ebur128} filter:
4530 ebur128=metadata=1,adrawgraph=lavfi.r128.M:min=-120:max=5
4535 Draw a grid on the input image.
4537 It accepts the following parameters:
4542 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
4546 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
4547 input width and height, respectively, minus @code{thickness}, so image gets
4548 framed. Default to 0.
4551 Specify the color of the grid. For the general syntax of this option,
4552 check the "Color" section in the ffmpeg-utils manual. If the special
4553 value @code{invert} is used, the grid color is the same as the
4554 video with inverted luma.
4557 The expression which sets the thickness of the grid line. Default value is @code{1}.
4559 See below for the list of accepted constants.
4562 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
4563 following constants:
4567 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
4571 horizontal and vertical chroma subsample values. For example for the
4572 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4576 The input grid cell width and height.
4579 The input sample aspect ratio.
4583 The x and y coordinates of some point of grid intersection (meant to configure offset).
4587 The width and height of the drawn cell.
4590 The thickness of the drawn cell.
4592 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
4593 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
4597 @subsection Examples
4601 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
4603 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
4607 Draw a white 3x3 grid with an opacity of 50%:
4609 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
4616 Draw a text string or text from a specified file on top of a video, using the
4617 libfreetype library.
4619 To enable compilation of this filter, you need to configure FFmpeg with
4620 @code{--enable-libfreetype}.
4621 To enable default font fallback and the @var{font} option you need to
4622 configure FFmpeg with @code{--enable-libfontconfig}.
4623 To enable the @var{text_shaping} option, you need to configure FFmpeg with
4624 @code{--enable-libfribidi}.
4628 It accepts the following parameters:
4633 Used to draw a box around text using the background color.
4634 The value must be either 1 (enable) or 0 (disable).
4635 The default value of @var{box} is 0.
4638 Set the width of the border to be drawn around the box using @var{boxcolor}.
4639 The default value of @var{boxborderw} is 0.
4642 The color to be used for drawing box around text. For the syntax of this
4643 option, check the "Color" section in the ffmpeg-utils manual.
4645 The default value of @var{boxcolor} is "white".
4648 Set the width of the border to be drawn around the text using @var{bordercolor}.
4649 The default value of @var{borderw} is 0.
4652 Set the color to be used for drawing border around text. For the syntax of this
4653 option, check the "Color" section in the ffmpeg-utils manual.
4655 The default value of @var{bordercolor} is "black".
4658 Select how the @var{text} is expanded. Can be either @code{none},
4659 @code{strftime} (deprecated) or
4660 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
4664 If true, check and fix text coords to avoid clipping.
4667 The color to be used for drawing fonts. For the syntax of this option, check
4668 the "Color" section in the ffmpeg-utils manual.
4670 The default value of @var{fontcolor} is "black".
4672 @item fontcolor_expr
4673 String which is expanded the same way as @var{text} to obtain dynamic
4674 @var{fontcolor} value. By default this option has empty value and is not
4675 processed. When this option is set, it overrides @var{fontcolor} option.
4678 The font family to be used for drawing text. By default Sans.
4681 The font file to be used for drawing text. The path must be included.
4682 This parameter is mandatory if the fontconfig support is disabled.
4685 This option does not exist, please see the timeline system
4688 Draw the text applying alpha blending. The value can
4689 be either a number between 0.0 and 1.0
4690 The expression accepts the same variables @var{x, y} do.
4691 The default value is 1.
4692 Please see fontcolor_expr
4695 The font size to be used for drawing text.
4696 The default value of @var{fontsize} is 16.
4699 If set to 1, attempt to shape the text (for example, reverse the order of
4700 right-to-left text and join Arabic characters) before drawing it.
4701 Otherwise, just draw the text exactly as given.
4702 By default 1 (if supported).
4705 The flags to be used for loading the fonts.
4707 The flags map the corresponding flags supported by libfreetype, and are
4708 a combination of the following values:
4715 @item vertical_layout
4716 @item force_autohint
4719 @item ignore_global_advance_width
4721 @item ignore_transform
4727 Default value is "default".
4729 For more information consult the documentation for the FT_LOAD_*
4733 The color to be used for drawing a shadow behind the drawn text. For the
4734 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
4736 The default value of @var{shadowcolor} is "black".
4740 The x and y offsets for the text shadow position with respect to the
4741 position of the text. They can be either positive or negative
4742 values. The default value for both is "0".
4745 The starting frame number for the n/frame_num variable. The default value
4749 The size in number of spaces to use for rendering the tab.
4753 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
4754 format. It can be used with or without text parameter. @var{timecode_rate}
4755 option must be specified.
4757 @item timecode_rate, rate, r
4758 Set the timecode frame rate (timecode only).
4761 The text string to be drawn. The text must be a sequence of UTF-8
4763 This parameter is mandatory if no file is specified with the parameter
4767 A text file containing text to be drawn. The text must be a sequence
4768 of UTF-8 encoded characters.
4770 This parameter is mandatory if no text string is specified with the
4771 parameter @var{text}.
4773 If both @var{text} and @var{textfile} are specified, an error is thrown.
4776 If set to 1, the @var{textfile} will be reloaded before each frame.
4777 Be sure to update it atomically, or it may be read partially, or even fail.
4781 The expressions which specify the offsets where text will be drawn
4782 within the video frame. They are relative to the top/left border of the
4785 The default value of @var{x} and @var{y} is "0".
4787 See below for the list of accepted constants and functions.
4790 The parameters for @var{x} and @var{y} are expressions containing the
4791 following constants and functions:
4795 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
4799 horizontal and vertical chroma subsample values. For example for the
4800 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4803 the height of each text line
4811 @item max_glyph_a, ascent
4812 the maximum distance from the baseline to the highest/upper grid
4813 coordinate used to place a glyph outline point, for all the rendered
4815 It is a positive value, due to the grid's orientation with the Y axis
4818 @item max_glyph_d, descent
4819 the maximum distance from the baseline to the lowest grid coordinate
4820 used to place a glyph outline point, for all the rendered glyphs.
4821 This is a negative value, due to the grid's orientation, with the Y axis
4825 maximum glyph height, that is the maximum height for all the glyphs
4826 contained in the rendered text, it is equivalent to @var{ascent} -
4830 maximum glyph width, that is the maximum width for all the glyphs
4831 contained in the rendered text
4834 the number of input frame, starting from 0
4836 @item rand(min, max)
4837 return a random number included between @var{min} and @var{max}
4840 The input sample aspect ratio.
4843 timestamp expressed in seconds, NAN if the input timestamp is unknown
4846 the height of the rendered text
4849 the width of the rendered text
4853 the x and y offset coordinates where the text is drawn.
4855 These parameters allow the @var{x} and @var{y} expressions to refer
4856 each other, so you can for example specify @code{y=x/dar}.
4859 @anchor{drawtext_expansion}
4860 @subsection Text expansion
4862 If @option{expansion} is set to @code{strftime},
4863 the filter recognizes strftime() sequences in the provided text and
4864 expands them accordingly. Check the documentation of strftime(). This
4865 feature is deprecated.
4867 If @option{expansion} is set to @code{none}, the text is printed verbatim.
4869 If @option{expansion} is set to @code{normal} (which is the default),
4870 the following expansion mechanism is used.
4872 The backslash character @samp{\}, followed by any character, always expands to
4873 the second character.
4875 Sequence of the form @code{%@{...@}} are expanded. The text between the
4876 braces is a function name, possibly followed by arguments separated by ':'.
4877 If the arguments contain special characters or delimiters (':' or '@}'),
4878 they should be escaped.
4880 Note that they probably must also be escaped as the value for the
4881 @option{text} option in the filter argument string and as the filter
4882 argument in the filtergraph description, and possibly also for the shell,
4883 that makes up to four levels of escaping; using a text file avoids these
4886 The following functions are available:
4891 The expression evaluation result.
4893 It must take one argument specifying the expression to be evaluated,
4894 which accepts the same constants and functions as the @var{x} and
4895 @var{y} values. Note that not all constants should be used, for
4896 example the text size is not known when evaluating the expression, so
4897 the constants @var{text_w} and @var{text_h} will have an undefined
4900 @item expr_int_format, eif
4901 Evaluate the expression's value and output as formatted integer.
4903 The first argument is the expression to be evaluated, just as for the @var{expr} function.
4904 The second argument specifies the output format. Allowed values are @samp{x},
4905 @samp{X}, @samp{d} and @samp{u}. They are treated exactly as in the
4906 @code{printf} function.
4907 The third parameter is optional and sets the number of positions taken by the output.
4908 It can be used to add padding with zeros from the left.
4911 The time at which the filter is running, expressed in UTC.
4912 It can accept an argument: a strftime() format string.
4915 The time at which the filter is running, expressed in the local time zone.
4916 It can accept an argument: a strftime() format string.
4919 Frame metadata. It must take one argument specifying metadata key.
4922 The frame number, starting from 0.
4925 A 1 character description of the current picture type.
4928 The timestamp of the current frame.
4929 It can take up to two arguments.
4931 The first argument is the format of the timestamp; it defaults to @code{flt}
4932 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
4933 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
4935 The second argument is an offset added to the timestamp.
4939 @subsection Examples
4943 Draw "Test Text" with font FreeSerif, using the default values for the
4944 optional parameters.
4947 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
4951 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
4952 and y=50 (counting from the top-left corner of the screen), text is
4953 yellow with a red box around it. Both the text and the box have an
4957 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
4958 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
4961 Note that the double quotes are not necessary if spaces are not used
4962 within the parameter list.
4965 Show the text at the center of the video frame:
4967 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
4971 Show a text line sliding from right to left in the last row of the video
4972 frame. The file @file{LONG_LINE} is assumed to contain a single line
4975 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
4979 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
4981 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
4985 Draw a single green letter "g", at the center of the input video.
4986 The glyph baseline is placed at half screen height.
4988 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
4992 Show text for 1 second every 3 seconds:
4994 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
4998 Use fontconfig to set the font. Note that the colons need to be escaped.
5000 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
5004 Print the date of a real-time encoding (see strftime(3)):
5006 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
5010 Show text fading in and out (appearing/disappearing):
5013 DS=1.0 # display start
5014 DE=10.0 # display end
5015 FID=1.5 # fade in duration
5016 FOD=5 # fade out duration
5017 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 @}"
5022 For more information about libfreetype, check:
5023 @url{http://www.freetype.org/}.
5025 For more information about fontconfig, check:
5026 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
5028 For more information about libfribidi, check:
5029 @url{http://fribidi.org/}.
5033 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
5035 The filter accepts the following options:
5040 Set low and high threshold values used by the Canny thresholding
5043 The high threshold selects the "strong" edge pixels, which are then
5044 connected through 8-connectivity with the "weak" edge pixels selected
5045 by the low threshold.
5047 @var{low} and @var{high} threshold values must be chosen in the range
5048 [0,1], and @var{low} should be lesser or equal to @var{high}.
5050 Default value for @var{low} is @code{20/255}, and default value for @var{high}
5054 Define the drawing mode.
5058 Draw white/gray wires on black background.
5061 Mix the colors to create a paint/cartoon effect.
5064 Default value is @var{wires}.
5067 @subsection Examples
5071 Standard edge detection with custom values for the hysteresis thresholding:
5073 edgedetect=low=0.1:high=0.4
5077 Painting effect without thresholding:
5079 edgedetect=mode=colormix:high=0
5084 Set brightness, contrast, saturation and approximate gamma adjustment.
5086 The filter accepts the following options:
5090 Set the contrast expression. The value must be a float value in range
5091 @code{-2.0} to @code{2.0}. The default value is "0".
5094 Set the brightness expression. The value must be a float value in
5095 range @code{-1.0} to @code{1.0}. The default value is "0".
5098 Set the saturation expression. The value must be a float in
5099 range @code{0.0} to @code{3.0}. The default value is "1".
5102 Set the gamma expression. The value must be a float in range
5103 @code{0.1} to @code{10.0}. The default value is "1".
5106 Set the gamma expression for red. The value must be a float in
5107 range @code{0.1} to @code{10.0}. The default value is "1".
5110 Set the gamma expression for green. The value must be a float in range
5111 @code{0.1} to @code{10.0}. The default value is "1".
5114 Set the gamma expression for blue. The value must be a float in range
5115 @code{0.1} to @code{10.0}. The default value is "1".
5118 Set the gamma weight expression. It can be used to reduce the effect
5119 of a high gamma value on bright image areas, e.g. keep them from
5120 getting overamplified and just plain white. The value must be a float
5121 in range @code{0.0} to @code{1.0}. A value of @code{0.0} turns the
5122 gamma correction all the way down while @code{1.0} leaves it at its
5123 full strength. Default is "1".
5126 Set when the expressions for brightness, contrast, saturation and
5127 gamma expressions are evaluated.
5129 It accepts the following values:
5132 only evaluate expressions once during the filter initialization or
5133 when a command is processed
5136 evaluate expressions for each incoming frame
5139 Default value is @samp{init}.
5142 The expressions accept the following parameters:
5145 frame count of the input frame starting from 0
5148 byte position of the corresponding packet in the input file, NAN if
5152 frame rate of the input video, NAN if the input frame rate is unknown
5155 timestamp expressed in seconds, NAN if the input timestamp is unknown
5158 @subsection Commands
5159 The filter supports the following commands:
5163 Set the contrast expression.
5166 Set the brightness expression.
5169 Set the saturation expression.
5172 Set the gamma expression.
5175 Set the gamma_r expression.
5178 Set gamma_g expression.
5181 Set gamma_b expression.
5184 Set gamma_weight expression.
5186 The command accepts the same syntax of the corresponding option.
5188 If the specified expression is not valid, it is kept at its current
5195 Apply erosion effect to the video.
5197 This filter replaces the pixel by the local(3x3) minimum.
5199 It accepts the following options:
5206 Allows to limit the maximum change for each plane, default is 65535.
5207 If 0, plane will remain unchanged.
5210 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
5213 Flags to local 3x3 coordinates maps like this:
5220 @section extractplanes
5222 Extract color channel components from input video stream into
5223 separate grayscale video streams.
5225 The filter accepts the following option:
5229 Set plane(s) to extract.
5231 Available values for planes are:
5242 Choosing planes not available in the input will result in an error.
5243 That means you cannot select @code{r}, @code{g}, @code{b} planes
5244 with @code{y}, @code{u}, @code{v} planes at same time.
5247 @subsection Examples
5251 Extract luma, u and v color channel component from input video frame
5252 into 3 grayscale outputs:
5254 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
5260 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
5262 For each input image, the filter will compute the optimal mapping from
5263 the input to the output given the codebook length, that is the number
5264 of distinct output colors.
5266 This filter accepts the following options.
5269 @item codebook_length, l
5270 Set codebook length. The value must be a positive integer, and
5271 represents the number of distinct output colors. Default value is 256.
5274 Set the maximum number of iterations to apply for computing the optimal
5275 mapping. The higher the value the better the result and the higher the
5276 computation time. Default value is 1.
5279 Set a random seed, must be an integer included between 0 and
5280 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
5281 will try to use a good random seed on a best effort basis.
5286 Apply a fade-in/out effect to the input video.
5288 It accepts the following parameters:
5292 The effect type can be either "in" for a fade-in, or "out" for a fade-out
5294 Default is @code{in}.
5296 @item start_frame, s
5297 Specify the number of the frame to start applying the fade
5298 effect at. Default is 0.
5301 The number of frames that the fade effect lasts. At the end of the
5302 fade-in effect, the output video will have the same intensity as the input video.
5303 At the end of the fade-out transition, the output video will be filled with the
5304 selected @option{color}.
5308 If set to 1, fade only alpha channel, if one exists on the input.
5311 @item start_time, st
5312 Specify the timestamp (in seconds) of the frame to start to apply the fade
5313 effect. If both start_frame and start_time are specified, the fade will start at
5314 whichever comes last. Default is 0.
5317 The number of seconds for which the fade effect has to last. At the end of the
5318 fade-in effect the output video will have the same intensity as the input video,
5319 at the end of the fade-out transition the output video will be filled with the
5320 selected @option{color}.
5321 If both duration and nb_frames are specified, duration is used. Default is 0
5322 (nb_frames is used by default).
5325 Specify the color of the fade. Default is "black".
5328 @subsection Examples
5332 Fade in the first 30 frames of video:
5337 The command above is equivalent to:
5343 Fade out the last 45 frames of a 200-frame video:
5346 fade=type=out:start_frame=155:nb_frames=45
5350 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
5352 fade=in:0:25, fade=out:975:25
5356 Make the first 5 frames yellow, then fade in from frame 5-24:
5358 fade=in:5:20:color=yellow
5362 Fade in alpha over first 25 frames of video:
5364 fade=in:0:25:alpha=1
5368 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
5370 fade=t=in:st=5.5:d=0.5
5376 Apply arbitrary expressions to samples in frequency domain
5380 Adjust the dc value (gain) of the luma plane of the image. The filter
5381 accepts an integer value in range @code{0} to @code{1000}. The default
5382 value is set to @code{0}.
5385 Adjust the dc value (gain) of the 1st chroma plane of the image. The
5386 filter accepts an integer value in range @code{0} to @code{1000}. The
5387 default value is set to @code{0}.
5390 Adjust the dc value (gain) of the 2nd chroma plane of the image. The
5391 filter accepts an integer value in range @code{0} to @code{1000}. The
5392 default value is set to @code{0}.
5395 Set the frequency domain weight expression for the luma plane.
5398 Set the frequency domain weight expression for the 1st chroma plane.
5401 Set the frequency domain weight expression for the 2nd chroma plane.
5403 The filter accepts the following variables:
5406 The coordinates of the current sample.
5410 The width and height of the image.
5413 @subsection Examples
5419 fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
5425 fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
5431 fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
5438 Extract a single field from an interlaced image using stride
5439 arithmetic to avoid wasting CPU time. The output frames are marked as
5442 The filter accepts the following options:
5446 Specify whether to extract the top (if the value is @code{0} or
5447 @code{top}) or the bottom field (if the value is @code{1} or
5453 Field matching filter for inverse telecine. It is meant to reconstruct the
5454 progressive frames from a telecined stream. The filter does not drop duplicated
5455 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
5456 followed by a decimation filter such as @ref{decimate} in the filtergraph.
5458 The separation of the field matching and the decimation is notably motivated by
5459 the possibility of inserting a de-interlacing filter fallback between the two.
5460 If the source has mixed telecined and real interlaced content,
5461 @code{fieldmatch} will not be able to match fields for the interlaced parts.
5462 But these remaining combed frames will be marked as interlaced, and thus can be
5463 de-interlaced by a later filter such as @ref{yadif} before decimation.
5465 In addition to the various configuration options, @code{fieldmatch} can take an
5466 optional second stream, activated through the @option{ppsrc} option. If
5467 enabled, the frames reconstruction will be based on the fields and frames from
5468 this second stream. This allows the first input to be pre-processed in order to
5469 help the various algorithms of the filter, while keeping the output lossless
5470 (assuming the fields are matched properly). Typically, a field-aware denoiser,
5471 or brightness/contrast adjustments can help.
5473 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
5474 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
5475 which @code{fieldmatch} is based on. While the semantic and usage are very
5476 close, some behaviour and options names can differ.
5478 The @ref{decimate} filter currently only works for constant frame rate input.
5479 Do not use @code{fieldmatch} and @ref{decimate} if your input has mixed
5480 telecined and progressive content with changing framerate.
5482 The filter accepts the following options:
5486 Specify the assumed field order of the input stream. Available values are:
5490 Auto detect parity (use FFmpeg's internal parity value).
5492 Assume bottom field first.
5494 Assume top field first.
5497 Note that it is sometimes recommended not to trust the parity announced by the
5500 Default value is @var{auto}.
5503 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
5504 sense that it won't risk creating jerkiness due to duplicate frames when
5505 possible, but if there are bad edits or blended fields it will end up
5506 outputting combed frames when a good match might actually exist. On the other
5507 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
5508 but will almost always find a good frame if there is one. The other values are
5509 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
5510 jerkiness and creating duplicate frames versus finding good matches in sections
5511 with bad edits, orphaned fields, blended fields, etc.
5513 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
5515 Available values are:
5519 2-way matching (p/c)
5521 2-way matching, and trying 3rd match if still combed (p/c + n)
5523 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
5525 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
5526 still combed (p/c + n + u/b)
5528 3-way matching (p/c/n)
5530 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
5531 detected as combed (p/c/n + u/b)
5534 The parenthesis at the end indicate the matches that would be used for that
5535 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
5538 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
5541 Default value is @var{pc_n}.
5544 Mark the main input stream as a pre-processed input, and enable the secondary
5545 input stream as the clean source to pick the fields from. See the filter
5546 introduction for more details. It is similar to the @option{clip2} feature from
5549 Default value is @code{0} (disabled).
5552 Set the field to match from. It is recommended to set this to the same value as
5553 @option{order} unless you experience matching failures with that setting. In
5554 certain circumstances changing the field that is used to match from can have a
5555 large impact on matching performance. Available values are:
5559 Automatic (same value as @option{order}).
5561 Match from the bottom field.
5563 Match from the top field.
5566 Default value is @var{auto}.
5569 Set whether or not chroma is included during the match comparisons. In most
5570 cases it is recommended to leave this enabled. You should set this to @code{0}
5571 only if your clip has bad chroma problems such as heavy rainbowing or other
5572 artifacts. Setting this to @code{0} could also be used to speed things up at
5573 the cost of some accuracy.
5575 Default value is @code{1}.
5579 These define an exclusion band which excludes the lines between @option{y0} and
5580 @option{y1} from being included in the field matching decision. An exclusion
5581 band can be used to ignore subtitles, a logo, or other things that may
5582 interfere with the matching. @option{y0} sets the starting scan line and
5583 @option{y1} sets the ending line; all lines in between @option{y0} and
5584 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
5585 @option{y0} and @option{y1} to the same value will disable the feature.
5586 @option{y0} and @option{y1} defaults to @code{0}.
5589 Set the scene change detection threshold as a percentage of maximum change on
5590 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
5591 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
5592 @option{scthresh} is @code{[0.0, 100.0]}.
5594 Default value is @code{12.0}.
5597 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
5598 account the combed scores of matches when deciding what match to use as the
5599 final match. Available values are:
5603 No final matching based on combed scores.
5605 Combed scores are only used when a scene change is detected.
5607 Use combed scores all the time.
5610 Default is @var{sc}.
5613 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
5614 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
5615 Available values are:
5619 No forced calculation.
5621 Force p/c/n calculations.
5623 Force p/c/n/u/b calculations.
5626 Default value is @var{none}.
5629 This is the area combing threshold used for combed frame detection. This
5630 essentially controls how "strong" or "visible" combing must be to be detected.
5631 Larger values mean combing must be more visible and smaller values mean combing
5632 can be less visible or strong and still be detected. Valid settings are from
5633 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
5634 be detected as combed). This is basically a pixel difference value. A good
5635 range is @code{[8, 12]}.
5637 Default value is @code{9}.
5640 Sets whether or not chroma is considered in the combed frame decision. Only
5641 disable this if your source has chroma problems (rainbowing, etc.) that are
5642 causing problems for the combed frame detection with chroma enabled. Actually,
5643 using @option{chroma}=@var{0} is usually more reliable, except for the case
5644 where there is chroma only combing in the source.
5646 Default value is @code{0}.
5650 Respectively set the x-axis and y-axis size of the window used during combed
5651 frame detection. This has to do with the size of the area in which
5652 @option{combpel} pixels are required to be detected as combed for a frame to be
5653 declared combed. See the @option{combpel} parameter description for more info.
5654 Possible values are any number that is a power of 2 starting at 4 and going up
5657 Default value is @code{16}.
5660 The number of combed pixels inside any of the @option{blocky} by
5661 @option{blockx} size blocks on the frame for the frame to be detected as
5662 combed. While @option{cthresh} controls how "visible" the combing must be, this
5663 setting controls "how much" combing there must be in any localized area (a
5664 window defined by the @option{blockx} and @option{blocky} settings) on the
5665 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
5666 which point no frames will ever be detected as combed). This setting is known
5667 as @option{MI} in TFM/VFM vocabulary.
5669 Default value is @code{80}.
5672 @anchor{p/c/n/u/b meaning}
5673 @subsection p/c/n/u/b meaning
5675 @subsubsection p/c/n
5677 We assume the following telecined stream:
5680 Top fields: 1 2 2 3 4
5681 Bottom fields: 1 2 3 4 4
5684 The numbers correspond to the progressive frame the fields relate to. Here, the
5685 first two frames are progressive, the 3rd and 4th are combed, and so on.
5687 When @code{fieldmatch} is configured to run a matching from bottom
5688 (@option{field}=@var{bottom}) this is how this input stream get transformed:
5693 B 1 2 3 4 4 <-- matching reference
5702 As a result of the field matching, we can see that some frames get duplicated.
5703 To perform a complete inverse telecine, you need to rely on a decimation filter
5704 after this operation. See for instance the @ref{decimate} filter.
5706 The same operation now matching from top fields (@option{field}=@var{top})
5711 T 1 2 2 3 4 <-- matching reference
5721 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
5722 basically, they refer to the frame and field of the opposite parity:
5725 @item @var{p} matches the field of the opposite parity in the previous frame
5726 @item @var{c} matches the field of the opposite parity in the current frame
5727 @item @var{n} matches the field of the opposite parity in the next frame
5732 The @var{u} and @var{b} matching are a bit special in the sense that they match
5733 from the opposite parity flag. In the following examples, we assume that we are
5734 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
5735 'x' is placed above and below each matched fields.
5737 With bottom matching (@option{field}=@var{bottom}):
5742 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
5743 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
5751 With top matching (@option{field}=@var{top}):
5756 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
5757 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
5765 @subsection Examples
5767 Simple IVTC of a top field first telecined stream:
5769 fieldmatch=order=tff:combmatch=none, decimate
5772 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
5774 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
5779 Transform the field order of the input video.
5781 It accepts the following parameters:
5786 The output field order. Valid values are @var{tff} for top field first or @var{bff}
5787 for bottom field first.
5790 The default value is @samp{tff}.
5792 The transformation is done by shifting the picture content up or down
5793 by one line, and filling the remaining line with appropriate picture content.
5794 This method is consistent with most broadcast field order converters.
5796 If the input video is not flagged as being interlaced, or it is already
5797 flagged as being of the required output field order, then this filter does
5798 not alter the incoming video.
5800 It is very useful when converting to or from PAL DV material,
5801 which is bottom field first.
5805 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
5810 Buffer input images and send them when they are requested.
5812 It is mainly useful when auto-inserted by the libavfilter
5815 It does not take parameters.
5819 Find a rectangular object
5821 It accepts the following options:
5825 Filepath of the object image, needs to be in gray8.
5828 Detection threshold, default is 0.5.
5831 Number of mipmaps, default is 3.
5833 @item xmin, ymin, xmax, ymax
5834 Specifies the rectangle in which to search.
5837 @subsection Examples
5841 Generate a representative palette of a given video using @command{ffmpeg}:
5843 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
5849 Cover a rectangular object
5851 It accepts the following options:
5855 Filepath of the optional cover image, needs to be in yuv420.
5860 It accepts the following values:
5863 cover it by the supplied image
5865 cover it by interpolating the surrounding pixels
5868 Default value is @var{blur}.
5871 @subsection Examples
5875 Generate a representative palette of a given video using @command{ffmpeg}:
5877 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
5884 Convert the input video to one of the specified pixel formats.
5885 Libavfilter will try to pick one that is suitable as input to
5888 It accepts the following parameters:
5892 A '|'-separated list of pixel format names, such as
5893 "pix_fmts=yuv420p|monow|rgb24".
5897 @subsection Examples
5901 Convert the input video to the @var{yuv420p} format
5903 format=pix_fmts=yuv420p
5906 Convert the input video to any of the formats in the list
5908 format=pix_fmts=yuv420p|yuv444p|yuv410p
5915 Convert the video to specified constant frame rate by duplicating or dropping
5916 frames as necessary.
5918 It accepts the following parameters:
5922 The desired output frame rate. The default is @code{25}.
5927 Possible values are:
5930 zero round towards 0
5934 round towards -infinity
5936 round towards +infinity
5940 The default is @code{near}.
5943 Assume the first PTS should be the given value, in seconds. This allows for
5944 padding/trimming at the start of stream. By default, no assumption is made
5945 about the first frame's expected PTS, so no padding or trimming is done.
5946 For example, this could be set to 0 to pad the beginning with duplicates of
5947 the first frame if a video stream starts after the audio stream or to trim any
5948 frames with a negative PTS.
5952 Alternatively, the options can be specified as a flat string:
5953 @var{fps}[:@var{round}].
5955 See also the @ref{setpts} filter.
5957 @subsection Examples
5961 A typical usage in order to set the fps to 25:
5967 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
5969 fps=fps=film:round=near
5975 Pack two different video streams into a stereoscopic video, setting proper
5976 metadata on supported codecs. The two views should have the same size and
5977 framerate and processing will stop when the shorter video ends. Please note
5978 that you may conveniently adjust view properties with the @ref{scale} and
5981 It accepts the following parameters:
5985 The desired packing format. Supported values are:
5990 The views are next to each other (default).
5993 The views are on top of each other.
5996 The views are packed by line.
5999 The views are packed by column.
6002 The views are temporally interleaved.
6011 # Convert left and right views into a frame-sequential video
6012 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
6014 # Convert views into a side-by-side video with the same output resolution as the input
6015 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
6020 Select one frame every N-th frame.
6022 This filter accepts the following option:
6025 Select frame after every @code{step} frames.
6026 Allowed values are positive integers higher than 0. Default value is @code{1}.
6032 Apply a frei0r effect to the input video.
6034 To enable the compilation of this filter, you need to install the frei0r
6035 header and configure FFmpeg with @code{--enable-frei0r}.
6037 It accepts the following parameters:
6042 The name of the frei0r effect to load. If the environment variable
6043 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
6044 directories specified by the colon-separated list in @env{FREIOR_PATH}.
6045 Otherwise, the standard frei0r paths are searched, in this order:
6046 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
6047 @file{/usr/lib/frei0r-1/}.
6050 A '|'-separated list of parameters to pass to the frei0r effect.
6054 A frei0r effect parameter can be a boolean (its value is either
6055 "y" or "n"), a double, a color (specified as
6056 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
6057 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
6058 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
6059 @var{X} and @var{Y} are floating point numbers) and/or a string.
6061 The number and types of parameters depend on the loaded effect. If an
6062 effect parameter is not specified, the default value is set.
6064 @subsection Examples
6068 Apply the distort0r effect, setting the first two double parameters:
6070 frei0r=filter_name=distort0r:filter_params=0.5|0.01
6074 Apply the colordistance effect, taking a color as the first parameter:
6076 frei0r=colordistance:0.2/0.3/0.4
6077 frei0r=colordistance:violet
6078 frei0r=colordistance:0x112233
6082 Apply the perspective effect, specifying the top left and top right image
6085 frei0r=perspective:0.2/0.2|0.8/0.2
6089 For more information, see
6090 @url{http://frei0r.dyne.org}
6094 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
6096 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
6097 processing filter, one of them is performed once per block, not per pixel.
6098 This allows for much higher speed.
6100 The filter accepts the following options:
6104 Set quality. This option defines the number of levels for averaging. It accepts
6105 an integer in the range 4-5. Default value is @code{4}.
6108 Force a constant quantization parameter. It accepts an integer in range 0-63.
6109 If not set, the filter will use the QP from the video stream (if available).
6112 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
6113 more details but also more artifacts, while higher values make the image smoother
6114 but also blurrier. Default value is @code{0} − PSNR optimal.
6117 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
6118 option may cause flicker since the B-Frames have often larger QP. Default is
6119 @code{0} (not enabled).
6125 The filter accepts the following options:
6129 Set the luminance expression.
6131 Set the chrominance blue expression.
6133 Set the chrominance red expression.
6135 Set the alpha expression.
6137 Set the red expression.
6139 Set the green expression.
6141 Set the blue expression.
6144 The colorspace is selected according to the specified options. If one
6145 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
6146 options is specified, the filter will automatically select a YCbCr
6147 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
6148 @option{blue_expr} options is specified, it will select an RGB
6151 If one of the chrominance expression is not defined, it falls back on the other
6152 one. If no alpha expression is specified it will evaluate to opaque value.
6153 If none of chrominance expressions are specified, they will evaluate
6154 to the luminance expression.
6156 The expressions can use the following variables and functions:
6160 The sequential number of the filtered frame, starting from @code{0}.
6164 The coordinates of the current sample.
6168 The width and height of the image.
6172 Width and height scale depending on the currently filtered plane. It is the
6173 ratio between the corresponding luma plane number of pixels and the current
6174 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
6175 @code{0.5,0.5} for chroma planes.
6178 Time of the current frame, expressed in seconds.
6181 Return the value of the pixel at location (@var{x},@var{y}) of the current
6185 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
6189 Return the value of the pixel at location (@var{x},@var{y}) of the
6190 blue-difference chroma plane. Return 0 if there is no such plane.
6193 Return the value of the pixel at location (@var{x},@var{y}) of the
6194 red-difference chroma plane. Return 0 if there is no such plane.
6199 Return the value of the pixel at location (@var{x},@var{y}) of the
6200 red/green/blue component. Return 0 if there is no such component.
6203 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
6204 plane. Return 0 if there is no such plane.
6207 For functions, if @var{x} and @var{y} are outside the area, the value will be
6208 automatically clipped to the closer edge.
6210 @subsection Examples
6214 Flip the image horizontally:
6220 Generate a bidimensional sine wave, with angle @code{PI/3} and a
6221 wavelength of 100 pixels:
6223 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
6227 Generate a fancy enigmatic moving light:
6229 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
6233 Generate a quick emboss effect:
6235 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
6239 Modify RGB components depending on pixel position:
6241 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
6245 Create a radial gradient that is the same size as the input (also see
6246 the @ref{vignette} filter):
6248 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
6252 Create a linear gradient to use as a mask for another filter, then
6253 compose with @ref{overlay}. In this example the video will gradually
6254 become more blurry from the top to the bottom of the y-axis as defined
6255 by the linear gradient:
6257 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
6263 Fix the banding artifacts that are sometimes introduced into nearly flat
6264 regions by truncation to 8bit color depth.
6265 Interpolate the gradients that should go where the bands are, and
6268 It is designed for playback only. Do not use it prior to
6269 lossy compression, because compression tends to lose the dither and
6270 bring back the bands.
6272 It accepts the following parameters:
6277 The maximum amount by which the filter will change any one pixel. This is also
6278 the threshold for detecting nearly flat regions. Acceptable values range from
6279 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
6283 The neighborhood to fit the gradient to. A larger radius makes for smoother
6284 gradients, but also prevents the filter from modifying the pixels near detailed
6285 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
6286 values will be clipped to the valid range.
6290 Alternatively, the options can be specified as a flat string:
6291 @var{strength}[:@var{radius}]
6293 @subsection Examples
6297 Apply the filter with a @code{3.5} strength and radius of @code{8}:
6303 Specify radius, omitting the strength (which will fall-back to the default
6314 Apply a Hald CLUT to a video stream.
6316 First input is the video stream to process, and second one is the Hald CLUT.
6317 The Hald CLUT input can be a simple picture or a complete video stream.
6319 The filter accepts the following options:
6323 Force termination when the shortest input terminates. Default is @code{0}.
6325 Continue applying the last CLUT after the end of the stream. A value of
6326 @code{0} disable the filter after the last frame of the CLUT is reached.
6327 Default is @code{1}.
6330 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
6331 filters share the same internals).
6333 More information about the Hald CLUT can be found on Eskil Steenberg's website
6334 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
6336 @subsection Workflow examples
6338 @subsubsection Hald CLUT video stream
6340 Generate an identity Hald CLUT stream altered with various effects:
6342 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
6345 Note: make sure you use a lossless codec.
6347 Then use it with @code{haldclut} to apply it on some random stream:
6349 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
6352 The Hald CLUT will be applied to the 10 first seconds (duration of
6353 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
6354 to the remaining frames of the @code{mandelbrot} stream.
6356 @subsubsection Hald CLUT with preview
6358 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
6359 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
6360 biggest possible square starting at the top left of the picture. The remaining
6361 padding pixels (bottom or right) will be ignored. This area can be used to add
6362 a preview of the Hald CLUT.
6364 Typically, the following generated Hald CLUT will be supported by the
6365 @code{haldclut} filter:
6368 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
6369 pad=iw+320 [padded_clut];
6370 smptebars=s=320x256, split [a][b];
6371 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
6372 [main][b] overlay=W-320" -frames:v 1 clut.png
6375 It contains the original and a preview of the effect of the CLUT: SMPTE color
6376 bars are displayed on the right-top, and below the same color bars processed by
6379 Then, the effect of this Hald CLUT can be visualized with:
6381 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
6386 Flip the input video horizontally.
6388 For example, to horizontally flip the input video with @command{ffmpeg}:
6390 ffmpeg -i in.avi -vf "hflip" out.avi
6394 This filter applies a global color histogram equalization on a
6397 It can be used to correct video that has a compressed range of pixel
6398 intensities. The filter redistributes the pixel intensities to
6399 equalize their distribution across the intensity range. It may be
6400 viewed as an "automatically adjusting contrast filter". This filter is
6401 useful only for correcting degraded or poorly captured source
6404 The filter accepts the following options:
6408 Determine the amount of equalization to be applied. As the strength
6409 is reduced, the distribution of pixel intensities more-and-more
6410 approaches that of the input frame. The value must be a float number
6411 in the range [0,1] and defaults to 0.200.
6414 Set the maximum intensity that can generated and scale the output
6415 values appropriately. The strength should be set as desired and then
6416 the intensity can be limited if needed to avoid washing-out. The value
6417 must be a float number in the range [0,1] and defaults to 0.210.
6420 Set the antibanding level. If enabled the filter will randomly vary
6421 the luminance of output pixels by a small amount to avoid banding of
6422 the histogram. Possible values are @code{none}, @code{weak} or
6423 @code{strong}. It defaults to @code{none}.
6428 Compute and draw a color distribution histogram for the input video.
6430 The computed histogram is a representation of the color component
6431 distribution in an image.
6433 The filter accepts the following options:
6439 It accepts the following values:
6442 Standard histogram that displays the color components distribution in an
6443 image. Displays color graph for each color component. Shows distribution of
6444 the Y, U, V, A or R, G, B components, depending on input format, in the
6445 current frame. Below each graph a color component scale meter is shown.
6448 Displays chroma values (U/V color placement) in a two dimensional
6449 graph (which is called a vectorscope). The brighter a pixel in the
6450 vectorscope, the more pixels of the input frame correspond to that pixel
6451 (i.e., more pixels have this chroma value). The V component is displayed on
6452 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
6453 side being V = 255. The U component is displayed on the vertical (Y) axis,
6454 with the top representing U = 0 and the bottom representing U = 255.
6456 The position of a white pixel in the graph corresponds to the chroma value of
6457 a pixel of the input clip. The graph can therefore be used to read the hue
6458 (color flavor) and the saturation (the dominance of the hue in the color). As
6459 the hue of a color changes, it moves around the square. At the center of the
6460 square the saturation is zero, which means that the corresponding pixel has no
6461 color. If the amount of a specific color is increased (while leaving the other
6462 colors unchanged) the saturation increases, and the indicator moves towards
6463 the edge of the square.
6466 Chroma values in vectorscope, similar as @code{color} but actual chroma values
6470 Per row/column color component graph. In row mode, the graph on the left side
6471 represents color component value 0 and the right side represents value = 255.
6472 In column mode, the top side represents color component value = 0 and bottom
6473 side represents value = 255.
6475 Default value is @code{levels}.
6478 Set height of level in @code{levels}. Default value is @code{200}.
6479 Allowed range is [50, 2048].
6482 Set height of color scale in @code{levels}. Default value is @code{12}.
6483 Allowed range is [0, 40].
6486 Set step for @code{waveform} mode. Smaller values are useful to find out how
6487 many values of the same luminance are distributed across input rows/columns.
6488 Default value is @code{10}. Allowed range is [1, 255].
6491 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
6492 Default is @code{row}.
6494 @item waveform_mirror
6495 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
6496 means mirrored. In mirrored mode, higher values will be represented on the left
6497 side for @code{row} mode and at the top for @code{column} mode. Default is
6498 @code{0} (unmirrored).
6501 Set display mode for @code{waveform} and @code{levels}.
6502 It accepts the following values:
6505 Display separate graph for the color components side by side in
6506 @code{row} waveform mode or one below the other in @code{column} waveform mode
6507 for @code{waveform} histogram mode. For @code{levels} histogram mode,
6508 per color component graphs are placed below each other.
6510 Using this display mode in @code{waveform} histogram mode makes it easy to
6511 spot color casts in the highlights and shadows of an image, by comparing the
6512 contours of the top and the bottom graphs of each waveform. Since whites,
6513 grays, and blacks are characterized by exactly equal amounts of red, green,
6514 and blue, neutral areas of the picture should display three waveforms of
6515 roughly equal width/height. If not, the correction is easy to perform by
6516 making level adjustments the three waveforms.
6519 Presents information identical to that in the @code{parade}, except
6520 that the graphs representing color components are superimposed directly
6523 This display mode in @code{waveform} histogram mode makes it easier to spot
6524 relative differences or similarities in overlapping areas of the color
6525 components that are supposed to be identical, such as neutral whites, grays,
6528 Default is @code{parade}.
6531 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
6532 Default is @code{linear}.
6535 @subsection Examples
6540 Calculate and draw histogram:
6542 ffplay -i input -vf histogram
6550 This is a high precision/quality 3d denoise filter. It aims to reduce
6551 image noise, producing smooth images and making still images really
6552 still. It should enhance compressibility.
6554 It accepts the following optional parameters:
6558 A non-negative floating point number which specifies spatial luma strength.
6561 @item chroma_spatial
6562 A non-negative floating point number which specifies spatial chroma strength.
6563 It defaults to 3.0*@var{luma_spatial}/4.0.
6566 A floating point number which specifies luma temporal strength. It defaults to
6567 6.0*@var{luma_spatial}/4.0.
6570 A floating point number which specifies chroma temporal strength. It defaults to
6571 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
6576 Apply a high-quality magnification filter designed for pixel art. This filter
6577 was originally created by Maxim Stepin.
6579 It accepts the following option:
6583 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
6584 @code{hq3x} and @code{4} for @code{hq4x}.
6585 Default is @code{3}.
6590 Modify the hue and/or the saturation of the input.
6592 It accepts the following parameters:
6596 Specify the hue angle as a number of degrees. It accepts an expression,
6597 and defaults to "0".
6600 Specify the saturation in the [-10,10] range. It accepts an expression and
6604 Specify the hue angle as a number of radians. It accepts an
6605 expression, and defaults to "0".
6608 Specify the brightness in the [-10,10] range. It accepts an expression and
6612 @option{h} and @option{H} are mutually exclusive, and can't be
6613 specified at the same time.
6615 The @option{b}, @option{h}, @option{H} and @option{s} option values are
6616 expressions containing the following constants:
6620 frame count of the input frame starting from 0
6623 presentation timestamp of the input frame expressed in time base units
6626 frame rate of the input video, NAN if the input frame rate is unknown
6629 timestamp expressed in seconds, NAN if the input timestamp is unknown
6632 time base of the input video
6635 @subsection Examples
6639 Set the hue to 90 degrees and the saturation to 1.0:
6645 Same command but expressing the hue in radians:
6651 Rotate hue and make the saturation swing between 0
6652 and 2 over a period of 1 second:
6654 hue="H=2*PI*t: s=sin(2*PI*t)+1"
6658 Apply a 3 seconds saturation fade-in effect starting at 0:
6663 The general fade-in expression can be written as:
6665 hue="s=min(0\, max((t-START)/DURATION\, 1))"
6669 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
6671 hue="s=max(0\, min(1\, (8-t)/3))"
6674 The general fade-out expression can be written as:
6676 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
6681 @subsection Commands
6683 This filter supports the following commands:
6689 Modify the hue and/or the saturation and/or brightness of the input video.
6690 The command accepts the same syntax of the corresponding option.
6692 If the specified expression is not valid, it is kept at its current
6698 Detect video interlacing type.
6700 This filter tries to detect if the input frames as interlaced, progressive,
6701 top or bottom field first. It will also try and detect fields that are
6702 repeated between adjacent frames (a sign of telecine).
6704 Single frame detection considers only immediately adjacent frames when classifying each frame.
6705 Multiple frame detection incorporates the classification history of previous frames.
6707 The filter will log these metadata values:
6710 @item single.current_frame
6711 Detected type of current frame using single-frame detection. One of:
6712 ``tff'' (top field first), ``bff'' (bottom field first),
6713 ``progressive'', or ``undetermined''
6716 Cumulative number of frames detected as top field first using single-frame detection.
6719 Cumulative number of frames detected as top field first using multiple-frame detection.
6722 Cumulative number of frames detected as bottom field first using single-frame detection.
6724 @item multiple.current_frame
6725 Detected type of current frame using multiple-frame detection. One of:
6726 ``tff'' (top field first), ``bff'' (bottom field first),
6727 ``progressive'', or ``undetermined''
6730 Cumulative number of frames detected as bottom field first using multiple-frame detection.
6732 @item single.progressive
6733 Cumulative number of frames detected as progressive using single-frame detection.
6735 @item multiple.progressive
6736 Cumulative number of frames detected as progressive using multiple-frame detection.
6738 @item single.undetermined
6739 Cumulative number of frames that could not be classified using single-frame detection.
6741 @item multiple.undetermined
6742 Cumulative number of frames that could not be classified using multiple-frame detection.
6744 @item repeated.current_frame
6745 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
6747 @item repeated.neither
6748 Cumulative number of frames with no repeated field.
6751 Cumulative number of frames with the top field repeated from the previous frame's top field.
6753 @item repeated.bottom
6754 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
6757 The filter accepts the following options:
6761 Set interlacing threshold.
6763 Set progressive threshold.
6765 Threshold for repeated field detection.
6767 Number of frames after which a given frame's contribution to the
6768 statistics is halved (i.e., it contributes only 0.5 to it's
6769 classification). The default of 0 means that all frames seen are given
6770 full weight of 1.0 forever.
6771 @item analyze_interlaced_flag
6772 When this is not 0 then idet will use the specified number of frames to determine
6773 if the interlaced flag is accurate, it will not count undetermined frames.
6774 If the flag is found to be accurate it will be used without any further
6775 computations, if it is found to be inaccurate it will be cleared without any
6776 further computations. This allows inserting the idet filter as a low computational
6777 method to clean up the interlaced flag
6782 Deinterleave or interleave fields.
6784 This filter allows one to process interlaced images fields without
6785 deinterlacing them. Deinterleaving splits the input frame into 2
6786 fields (so called half pictures). Odd lines are moved to the top
6787 half of the output image, even lines to the bottom half.
6788 You can process (filter) them independently and then re-interleave them.
6790 The filter accepts the following options:
6794 @item chroma_mode, c
6796 Available values for @var{luma_mode}, @var{chroma_mode} and
6797 @var{alpha_mode} are:
6803 @item deinterleave, d
6804 Deinterleave fields, placing one above the other.
6807 Interleave fields. Reverse the effect of deinterleaving.
6809 Default value is @code{none}.
6812 @item chroma_swap, cs
6813 @item alpha_swap, as
6814 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
6819 Apply inflate effect to the video.
6821 This filter replaces the pixel by the local(3x3) average by taking into account
6822 only values higher than the pixel.
6824 It accepts the following options:
6831 Allows to limit the maximum change for each plane, default is 65535.
6832 If 0, plane will remain unchanged.
6837 Simple interlacing filter from progressive contents. This interleaves upper (or
6838 lower) lines from odd frames with lower (or upper) lines from even frames,
6839 halving the frame rate and preserving image height.
6842 Original Original New Frame
6843 Frame 'j' Frame 'j+1' (tff)
6844 ========== =========== ==================
6845 Line 0 --------------------> Frame 'j' Line 0
6846 Line 1 Line 1 ----> Frame 'j+1' Line 1
6847 Line 2 ---------------------> Frame 'j' Line 2
6848 Line 3 Line 3 ----> Frame 'j+1' Line 3
6850 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
6853 It accepts the following optional parameters:
6857 This determines whether the interlaced frame is taken from the even
6858 (tff - default) or odd (bff) lines of the progressive frame.
6861 Enable (default) or disable the vertical lowpass filter to avoid twitter
6862 interlacing and reduce moire patterns.
6867 Deinterlace input video by applying Donald Graft's adaptive kernel
6868 deinterling. Work on interlaced parts of a video to produce
6871 The description of the accepted parameters follows.
6875 Set the threshold which affects the filter's tolerance when
6876 determining if a pixel line must be processed. It must be an integer
6877 in the range [0,255] and defaults to 10. A value of 0 will result in
6878 applying the process on every pixels.
6881 Paint pixels exceeding the threshold value to white if set to 1.
6885 Set the fields order. Swap fields if set to 1, leave fields alone if
6889 Enable additional sharpening if set to 1. Default is 0.
6892 Enable twoway sharpening if set to 1. Default is 0.
6895 @subsection Examples
6899 Apply default values:
6901 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
6905 Enable additional sharpening:
6911 Paint processed pixels in white:
6917 @section lenscorrection
6919 Correct radial lens distortion
6921 This filter can be used to correct for radial distortion as can result from the use
6922 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
6923 one can use tools available for example as part of opencv or simply trial-and-error.
6924 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
6925 and extract the k1 and k2 coefficients from the resulting matrix.
6927 Note that effectively the same filter is available in the open-source tools Krita and
6928 Digikam from the KDE project.
6930 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
6931 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
6932 brightness distribution, so you may want to use both filters together in certain
6933 cases, though you will have to take care of ordering, i.e. whether vignetting should
6934 be applied before or after lens correction.
6938 The filter accepts the following options:
6942 Relative x-coordinate of the focal point of the image, and thereby the center of the
6943 distortion. This value has a range [0,1] and is expressed as fractions of the image
6946 Relative y-coordinate of the focal point of the image, and thereby the center of the
6947 distortion. This value has a range [0,1] and is expressed as fractions of the image
6950 Coefficient of the quadratic correction term. 0.5 means no correction.
6952 Coefficient of the double quadratic correction term. 0.5 means no correction.
6955 The formula that generates the correction is:
6957 @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)
6959 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
6960 distances from the focal point in the source and target images, respectively.
6965 Apply a 3D LUT to an input video.
6967 The filter accepts the following options:
6971 Set the 3D LUT file name.
6973 Currently supported formats:
6985 Select interpolation mode.
6987 Available values are:
6991 Use values from the nearest defined point.
6993 Interpolate values using the 8 points defining a cube.
6995 Interpolate values using a tetrahedron.
6999 @section lut, lutrgb, lutyuv
7001 Compute a look-up table for binding each pixel component input value
7002 to an output value, and apply it to the input video.
7004 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
7005 to an RGB input video.
7007 These filters accept the following parameters:
7010 set first pixel component expression
7012 set second pixel component expression
7014 set third pixel component expression
7016 set fourth pixel component expression, corresponds to the alpha component
7019 set red component expression
7021 set green component expression
7023 set blue component expression
7025 alpha component expression
7028 set Y/luminance component expression
7030 set U/Cb component expression
7032 set V/Cr component expression
7035 Each of them specifies the expression to use for computing the lookup table for
7036 the corresponding pixel component values.
7038 The exact component associated to each of the @var{c*} options depends on the
7041 The @var{lut} filter requires either YUV or RGB pixel formats in input,
7042 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
7044 The expressions can contain the following constants and functions:
7049 The input width and height.
7052 The input value for the pixel component.
7055 The input value, clipped to the @var{minval}-@var{maxval} range.
7058 The maximum value for the pixel component.
7061 The minimum value for the pixel component.
7064 The negated value for the pixel component value, clipped to the
7065 @var{minval}-@var{maxval} range; it corresponds to the expression
7066 "maxval-clipval+minval".
7069 The computed value in @var{val}, clipped to the
7070 @var{minval}-@var{maxval} range.
7072 @item gammaval(gamma)
7073 The computed gamma correction value of the pixel component value,
7074 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
7076 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
7080 All expressions default to "val".
7082 @subsection Examples
7088 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
7089 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
7092 The above is the same as:
7094 lutrgb="r=negval:g=negval:b=negval"
7095 lutyuv="y=negval:u=negval:v=negval"
7105 Remove chroma components, turning the video into a graytone image:
7107 lutyuv="u=128:v=128"
7111 Apply a luma burning effect:
7117 Remove green and blue components:
7123 Set a constant alpha channel value on input:
7125 format=rgba,lutrgb=a="maxval-minval/2"
7129 Correct luminance gamma by a factor of 0.5:
7131 lutyuv=y=gammaval(0.5)
7135 Discard least significant bits of luma:
7137 lutyuv=y='bitand(val, 128+64+32)'
7141 @section mergeplanes
7143 Merge color channel components from several video streams.
7145 The filter accepts up to 4 input streams, and merge selected input
7146 planes to the output video.
7148 This filter accepts the following options:
7151 Set input to output plane mapping. Default is @code{0}.
7153 The mappings is specified as a bitmap. It should be specified as a
7154 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
7155 mapping for the first plane of the output stream. 'A' sets the number of
7156 the input stream to use (from 0 to 3), and 'a' the plane number of the
7157 corresponding input to use (from 0 to 3). The rest of the mappings is
7158 similar, 'Bb' describes the mapping for the output stream second
7159 plane, 'Cc' describes the mapping for the output stream third plane and
7160 'Dd' describes the mapping for the output stream fourth plane.
7163 Set output pixel format. Default is @code{yuva444p}.
7166 @subsection Examples
7170 Merge three gray video streams of same width and height into single video stream:
7172 [a0][a1][a2]mergeplanes=0x001020:yuv444p
7176 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
7178 [a0][a1]mergeplanes=0x00010210:yuva444p
7182 Swap Y and A plane in yuva444p stream:
7184 format=yuva444p,mergeplanes=0x03010200:yuva444p
7188 Swap U and V plane in yuv420p stream:
7190 format=yuv420p,mergeplanes=0x000201:yuv420p
7194 Cast a rgb24 clip to yuv444p:
7196 format=rgb24,mergeplanes=0x000102:yuv444p
7202 Apply motion-compensation deinterlacing.
7204 It needs one field per frame as input and must thus be used together
7205 with yadif=1/3 or equivalent.
7207 This filter accepts the following options:
7210 Set the deinterlacing mode.
7212 It accepts one of the following values:
7217 use iterative motion estimation
7219 like @samp{slow}, but use multiple reference frames.
7221 Default value is @samp{fast}.
7224 Set the picture field parity assumed for the input video. It must be
7225 one of the following values:
7229 assume top field first
7231 assume bottom field first
7234 Default value is @samp{bff}.
7237 Set per-block quantization parameter (QP) used by the internal
7240 Higher values should result in a smoother motion vector field but less
7241 optimal individual vectors. Default value is 1.
7246 Drop frames that do not differ greatly from the previous frame in
7247 order to reduce frame rate.
7249 The main use of this filter is for very-low-bitrate encoding
7250 (e.g. streaming over dialup modem), but it could in theory be used for
7251 fixing movies that were inverse-telecined incorrectly.
7253 A description of the accepted options follows.
7257 Set the maximum number of consecutive frames which can be dropped (if
7258 positive), or the minimum interval between dropped frames (if
7259 negative). If the value is 0, the frame is dropped unregarding the
7260 number of previous sequentially dropped frames.
7267 Set the dropping threshold values.
7269 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
7270 represent actual pixel value differences, so a threshold of 64
7271 corresponds to 1 unit of difference for each pixel, or the same spread
7272 out differently over the block.
7274 A frame is a candidate for dropping if no 8x8 blocks differ by more
7275 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
7276 meaning the whole image) differ by more than a threshold of @option{lo}.
7278 Default value for @option{hi} is 64*12, default value for @option{lo} is
7279 64*5, and default value for @option{frac} is 0.33.
7287 It accepts an integer in input; if non-zero it negates the
7288 alpha component (if available). The default value in input is 0.
7292 Force libavfilter not to use any of the specified pixel formats for the
7293 input to the next filter.
7295 It accepts the following parameters:
7299 A '|'-separated list of pixel format names, such as
7300 apix_fmts=yuv420p|monow|rgb24".
7304 @subsection Examples
7308 Force libavfilter to use a format different from @var{yuv420p} for the
7309 input to the vflip filter:
7311 noformat=pix_fmts=yuv420p,vflip
7315 Convert the input video to any of the formats not contained in the list:
7317 noformat=yuv420p|yuv444p|yuv410p
7323 Add noise on video input frame.
7325 The filter accepts the following options:
7333 Set noise seed for specific pixel component or all pixel components in case
7334 of @var{all_seed}. Default value is @code{123457}.
7336 @item all_strength, alls
7337 @item c0_strength, c0s
7338 @item c1_strength, c1s
7339 @item c2_strength, c2s
7340 @item c3_strength, c3s
7341 Set noise strength for specific pixel component or all pixel components in case
7342 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
7344 @item all_flags, allf
7349 Set pixel component flags or set flags for all components if @var{all_flags}.
7350 Available values for component flags are:
7353 averaged temporal noise (smoother)
7355 mix random noise with a (semi)regular pattern
7357 temporal noise (noise pattern changes between frames)
7359 uniform noise (gaussian otherwise)
7363 @subsection Examples
7365 Add temporal and uniform noise to input video:
7367 noise=alls=20:allf=t+u
7372 Pass the video source unchanged to the output.
7376 Apply a video transform using libopencv.
7378 To enable this filter, install the libopencv library and headers and
7379 configure FFmpeg with @code{--enable-libopencv}.
7381 It accepts the following parameters:
7386 The name of the libopencv filter to apply.
7389 The parameters to pass to the libopencv filter. If not specified, the default
7394 Refer to the official libopencv documentation for more precise
7396 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
7398 Several libopencv filters are supported; see the following subsections.
7403 Dilate an image by using a specific structuring element.
7404 It corresponds to the libopencv function @code{cvDilate}.
7406 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
7408 @var{struct_el} represents a structuring element, and has the syntax:
7409 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
7411 @var{cols} and @var{rows} represent the number of columns and rows of
7412 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
7413 point, and @var{shape} the shape for the structuring element. @var{shape}
7414 must be "rect", "cross", "ellipse", or "custom".
7416 If the value for @var{shape} is "custom", it must be followed by a
7417 string of the form "=@var{filename}". The file with name
7418 @var{filename} is assumed to represent a binary image, with each
7419 printable character corresponding to a bright pixel. When a custom
7420 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
7421 or columns and rows of the read file are assumed instead.
7423 The default value for @var{struct_el} is "3x3+0x0/rect".
7425 @var{nb_iterations} specifies the number of times the transform is
7426 applied to the image, and defaults to 1.
7430 # Use the default values
7433 # Dilate using a structuring element with a 5x5 cross, iterating two times
7434 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
7436 # Read the shape from the file diamond.shape, iterating two times.
7437 # The file diamond.shape may contain a pattern of characters like this
7443 # The specified columns and rows are ignored
7444 # but the anchor point coordinates are not
7445 ocv=dilate:0x0+2x2/custom=diamond.shape|2
7450 Erode an image by using a specific structuring element.
7451 It corresponds to the libopencv function @code{cvErode}.
7453 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
7454 with the same syntax and semantics as the @ref{dilate} filter.
7458 Smooth the input video.
7460 The filter takes the following parameters:
7461 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
7463 @var{type} is the type of smooth filter to apply, and must be one of
7464 the following values: "blur", "blur_no_scale", "median", "gaussian",
7465 or "bilateral". The default value is "gaussian".
7467 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
7468 depend on the smooth type. @var{param1} and
7469 @var{param2} accept integer positive values or 0. @var{param3} and
7470 @var{param4} accept floating point values.
7472 The default value for @var{param1} is 3. The default value for the
7473 other parameters is 0.
7475 These parameters correspond to the parameters assigned to the
7476 libopencv function @code{cvSmooth}.
7481 Overlay one video on top of another.
7483 It takes two inputs and has one output. The first input is the "main"
7484 video on which the second input is overlaid.
7486 It accepts the following parameters:
7488 A description of the accepted options follows.
7493 Set the expression for the x and y coordinates of the overlaid video
7494 on the main video. Default value is "0" for both expressions. In case
7495 the expression is invalid, it is set to a huge value (meaning that the
7496 overlay will not be displayed within the output visible area).
7499 The action to take when EOF is encountered on the secondary input; it accepts
7500 one of the following values:
7504 Repeat the last frame (the default).
7508 Pass the main input through.
7512 Set when the expressions for @option{x}, and @option{y} are evaluated.
7514 It accepts the following values:
7517 only evaluate expressions once during the filter initialization or
7518 when a command is processed
7521 evaluate expressions for each incoming frame
7524 Default value is @samp{frame}.
7527 If set to 1, force the output to terminate when the shortest input
7528 terminates. Default value is 0.
7531 Set the format for the output video.
7533 It accepts the following values:
7548 Default value is @samp{yuv420}.
7550 @item rgb @emph{(deprecated)}
7551 If set to 1, force the filter to accept inputs in the RGB
7552 color space. Default value is 0. This option is deprecated, use
7553 @option{format} instead.
7556 If set to 1, force the filter to draw the last overlay frame over the
7557 main input until the end of the stream. A value of 0 disables this
7558 behavior. Default value is 1.
7561 The @option{x}, and @option{y} expressions can contain the following
7567 The main input width and height.
7571 The overlay input width and height.
7575 The computed values for @var{x} and @var{y}. They are evaluated for
7580 horizontal and vertical chroma subsample values of the output
7581 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
7585 the number of input frame, starting from 0
7588 the position in the file of the input frame, NAN if unknown
7591 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
7595 Note that the @var{n}, @var{pos}, @var{t} variables are available only
7596 when evaluation is done @emph{per frame}, and will evaluate to NAN
7597 when @option{eval} is set to @samp{init}.
7599 Be aware that frames are taken from each input video in timestamp
7600 order, hence, if their initial timestamps differ, it is a good idea
7601 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
7602 have them begin in the same zero timestamp, as the example for
7603 the @var{movie} filter does.
7605 You can chain together more overlays but you should test the
7606 efficiency of such approach.
7608 @subsection Commands
7610 This filter supports the following commands:
7614 Modify the x and y of the overlay input.
7615 The command accepts the same syntax of the corresponding option.
7617 If the specified expression is not valid, it is kept at its current
7621 @subsection Examples
7625 Draw the overlay at 10 pixels from the bottom right corner of the main
7628 overlay=main_w-overlay_w-10:main_h-overlay_h-10
7631 Using named options the example above becomes:
7633 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
7637 Insert a transparent PNG logo in the bottom left corner of the input,
7638 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
7640 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
7644 Insert 2 different transparent PNG logos (second logo on bottom
7645 right corner) using the @command{ffmpeg} tool:
7647 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
7651 Add a transparent color layer on top of the main video; @code{WxH}
7652 must specify the size of the main input to the overlay filter:
7654 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
7658 Play an original video and a filtered version (here with the deshake
7659 filter) side by side using the @command{ffplay} tool:
7661 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
7664 The above command is the same as:
7666 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
7670 Make a sliding overlay appearing from the left to the right top part of the
7671 screen starting since time 2:
7673 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
7677 Compose output by putting two input videos side to side:
7679 ffmpeg -i left.avi -i right.avi -filter_complex "
7680 nullsrc=size=200x100 [background];
7681 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
7682 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
7683 [background][left] overlay=shortest=1 [background+left];
7684 [background+left][right] overlay=shortest=1:x=100 [left+right]
7689 Mask 10-20 seconds of a video by applying the delogo filter to a section
7691 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
7692 -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]'
7697 Chain several overlays in cascade:
7699 nullsrc=s=200x200 [bg];
7700 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
7701 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
7702 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
7703 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
7704 [in3] null, [mid2] overlay=100:100 [out0]
7711 Apply Overcomplete Wavelet denoiser.
7713 The filter accepts the following options:
7719 Larger depth values will denoise lower frequency components more, but
7720 slow down filtering.
7722 Must be an int in the range 8-16, default is @code{8}.
7724 @item luma_strength, ls
7727 Must be a double value in the range 0-1000, default is @code{1.0}.
7729 @item chroma_strength, cs
7730 Set chroma strength.
7732 Must be a double value in the range 0-1000, default is @code{1.0}.
7737 Add paddings to the input image, and place the original input at the
7738 provided @var{x}, @var{y} coordinates.
7740 It accepts the following parameters:
7745 Specify an expression for the size of the output image with the
7746 paddings added. If the value for @var{width} or @var{height} is 0, the
7747 corresponding input size is used for the output.
7749 The @var{width} expression can reference the value set by the
7750 @var{height} expression, and vice versa.
7752 The default value of @var{width} and @var{height} is 0.
7756 Specify the offsets to place the input image at within the padded area,
7757 with respect to the top/left border of the output image.
7759 The @var{x} expression can reference the value set by the @var{y}
7760 expression, and vice versa.
7762 The default value of @var{x} and @var{y} is 0.
7765 Specify the color of the padded area. For the syntax of this option,
7766 check the "Color" section in the ffmpeg-utils manual.
7768 The default value of @var{color} is "black".
7771 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
7772 options are expressions containing the following constants:
7777 The input video width and height.
7781 These are the same as @var{in_w} and @var{in_h}.
7785 The output width and height (the size of the padded area), as
7786 specified by the @var{width} and @var{height} expressions.
7790 These are the same as @var{out_w} and @var{out_h}.
7794 The x and y offsets as specified by the @var{x} and @var{y}
7795 expressions, or NAN if not yet specified.
7798 same as @var{iw} / @var{ih}
7801 input sample aspect ratio
7804 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
7808 The horizontal and vertical chroma subsample values. For example for the
7809 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7812 @subsection Examples
7816 Add paddings with the color "violet" to the input video. The output video
7817 size is 640x480, and the top-left corner of the input video is placed at
7820 pad=640:480:0:40:violet
7823 The example above is equivalent to the following command:
7825 pad=width=640:height=480:x=0:y=40:color=violet
7829 Pad the input to get an output with dimensions increased by 3/2,
7830 and put the input video at the center of the padded area:
7832 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
7836 Pad the input to get a squared output with size equal to the maximum
7837 value between the input width and height, and put the input video at
7838 the center of the padded area:
7840 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
7844 Pad the input to get a final w/h ratio of 16:9:
7846 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
7850 In case of anamorphic video, in order to set the output display aspect
7851 correctly, it is necessary to use @var{sar} in the expression,
7852 according to the relation:
7854 (ih * X / ih) * sar = output_dar
7855 X = output_dar / sar
7858 Thus the previous example needs to be modified to:
7860 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
7864 Double the output size and put the input video in the bottom-right
7865 corner of the output padded area:
7867 pad="2*iw:2*ih:ow-iw:oh-ih"
7874 Generate one palette for a whole video stream.
7876 It accepts the following options:
7880 Set the maximum number of colors to quantize in the palette.
7881 Note: the palette will still contain 256 colors; the unused palette entries
7884 @item reserve_transparent
7885 Create a palette of 255 colors maximum and reserve the last one for
7886 transparency. Reserving the transparency color is useful for GIF optimization.
7887 If not set, the maximum of colors in the palette will be 256. You probably want
7888 to disable this option for a standalone image.
7892 Set statistics mode.
7894 It accepts the following values:
7897 Compute full frame histograms.
7899 Compute histograms only for the part that differs from previous frame. This
7900 might be relevant to give more importance to the moving part of your input if
7901 the background is static.
7904 Default value is @var{full}.
7907 The filter also exports the frame metadata @code{lavfi.color_quant_ratio}
7908 (@code{nb_color_in / nb_color_out}) which you can use to evaluate the degree of
7909 color quantization of the palette. This information is also visible at
7910 @var{info} logging level.
7912 @subsection Examples
7916 Generate a representative palette of a given video using @command{ffmpeg}:
7918 ffmpeg -i input.mkv -vf palettegen palette.png
7924 Use a palette to downsample an input video stream.
7926 The filter takes two inputs: one video stream and a palette. The palette must
7927 be a 256 pixels image.
7929 It accepts the following options:
7933 Select dithering mode. Available algorithms are:
7936 Ordered 8x8 bayer dithering (deterministic)
7938 Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
7939 Note: this dithering is sometimes considered "wrong" and is included as a
7941 @item floyd_steinberg
7942 Floyd and Steingberg dithering (error diffusion)
7944 Frankie Sierra dithering v2 (error diffusion)
7946 Frankie Sierra dithering v2 "Lite" (error diffusion)
7949 Default is @var{sierra2_4a}.
7952 When @var{bayer} dithering is selected, this option defines the scale of the
7953 pattern (how much the crosshatch pattern is visible). A low value means more
7954 visible pattern for less banding, and higher value means less visible pattern
7955 at the cost of more banding.
7957 The option must be an integer value in the range [0,5]. Default is @var{2}.
7960 If set, define the zone to process
7964 Only the changing rectangle will be reprocessed. This is similar to GIF
7965 cropping/offsetting compression mechanism. This option can be useful for speed
7966 if only a part of the image is changing, and has use cases such as limiting the
7967 scope of the error diffusal @option{dither} to the rectangle that bounds the
7968 moving scene (it leads to more deterministic output if the scene doesn't change
7969 much, and as a result less moving noise and better GIF compression).
7972 Default is @var{none}.
7975 @subsection Examples
7979 Use a palette (generated for example with @ref{palettegen}) to encode a GIF
7980 using @command{ffmpeg}:
7982 ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
7986 @section perspective
7988 Correct perspective of video not recorded perpendicular to the screen.
7990 A description of the accepted parameters follows.
8001 Set coordinates expression for top left, top right, bottom left and bottom right corners.
8002 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
8003 If the @code{sense} option is set to @code{source}, then the specified points will be sent
8004 to the corners of the destination. If the @code{sense} option is set to @code{destination},
8005 then the corners of the source will be sent to the specified coordinates.
8007 The expressions can use the following variables:
8012 the width and height of video frame.
8016 Set interpolation for perspective correction.
8018 It accepts the following values:
8024 Default value is @samp{linear}.
8027 Set interpretation of coordinate options.
8029 It accepts the following values:
8033 Send point in the source specified by the given coordinates to
8034 the corners of the destination.
8036 @item 1, destination
8038 Send the corners of the source to the point in the destination specified
8039 by the given coordinates.
8041 Default value is @samp{source}.
8047 Delay interlaced video by one field time so that the field order changes.
8049 The intended use is to fix PAL movies that have been captured with the
8050 opposite field order to the film-to-video transfer.
8052 A description of the accepted parameters follows.
8058 It accepts the following values:
8061 Capture field order top-first, transfer bottom-first.
8062 Filter will delay the bottom field.
8065 Capture field order bottom-first, transfer top-first.
8066 Filter will delay the top field.
8069 Capture and transfer with the same field order. This mode only exists
8070 for the documentation of the other options to refer to, but if you
8071 actually select it, the filter will faithfully do nothing.
8074 Capture field order determined automatically by field flags, transfer
8076 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
8077 basis using field flags. If no field information is available,
8078 then this works just like @samp{u}.
8081 Capture unknown or varying, transfer opposite.
8082 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
8083 analyzing the images and selecting the alternative that produces best
8084 match between the fields.
8087 Capture top-first, transfer unknown or varying.
8088 Filter selects among @samp{t} and @samp{p} using image analysis.
8091 Capture bottom-first, transfer unknown or varying.
8092 Filter selects among @samp{b} and @samp{p} using image analysis.
8095 Capture determined by field flags, transfer unknown or varying.
8096 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
8097 image analysis. If no field information is available, then this works just
8098 like @samp{U}. This is the default mode.
8101 Both capture and transfer unknown or varying.
8102 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
8106 @section pixdesctest
8108 Pixel format descriptor test filter, mainly useful for internal
8109 testing. The output video should be equal to the input video.
8113 format=monow, pixdesctest
8116 can be used to test the monowhite pixel format descriptor definition.
8120 Enable the specified chain of postprocessing subfilters using libpostproc. This
8121 library should be automatically selected with a GPL build (@code{--enable-gpl}).
8122 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
8123 Each subfilter and some options have a short and a long name that can be used
8124 interchangeably, i.e. dr/dering are the same.
8126 The filters accept the following options:
8130 Set postprocessing subfilters string.
8133 All subfilters share common options to determine their scope:
8137 Honor the quality commands for this subfilter.
8140 Do chrominance filtering, too (default).
8143 Do luminance filtering only (no chrominance).
8146 Do chrominance filtering only (no luminance).
8149 These options can be appended after the subfilter name, separated by a '|'.
8151 Available subfilters are:
8154 @item hb/hdeblock[|difference[|flatness]]
8155 Horizontal deblocking filter
8158 Difference factor where higher values mean more deblocking (default: @code{32}).
8160 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8163 @item vb/vdeblock[|difference[|flatness]]
8164 Vertical deblocking filter
8167 Difference factor where higher values mean more deblocking (default: @code{32}).
8169 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8172 @item ha/hadeblock[|difference[|flatness]]
8173 Accurate horizontal deblocking filter
8176 Difference factor where higher values mean more deblocking (default: @code{32}).
8178 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8181 @item va/vadeblock[|difference[|flatness]]
8182 Accurate vertical deblocking filter
8185 Difference factor where higher values mean more deblocking (default: @code{32}).
8187 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8191 The horizontal and vertical deblocking filters share the difference and
8192 flatness values so you cannot set different horizontal and vertical
8197 Experimental horizontal deblocking filter
8200 Experimental vertical deblocking filter
8205 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
8208 larger -> stronger filtering
8210 larger -> stronger filtering
8212 larger -> stronger filtering
8215 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
8218 Stretch luminance to @code{0-255}.
8221 @item lb/linblenddeint
8222 Linear blend deinterlacing filter that deinterlaces the given block by
8223 filtering all lines with a @code{(1 2 1)} filter.
8225 @item li/linipoldeint
8226 Linear interpolating deinterlacing filter that deinterlaces the given block by
8227 linearly interpolating every second line.
8229 @item ci/cubicipoldeint
8230 Cubic interpolating deinterlacing filter deinterlaces the given block by
8231 cubically interpolating every second line.
8233 @item md/mediandeint
8234 Median deinterlacing filter that deinterlaces the given block by applying a
8235 median filter to every second line.
8237 @item fd/ffmpegdeint
8238 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
8239 second line with a @code{(-1 4 2 4 -1)} filter.
8242 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
8243 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
8245 @item fq/forceQuant[|quantizer]
8246 Overrides the quantizer table from the input with the constant quantizer you
8254 Default pp filter combination (@code{hb|a,vb|a,dr|a})
8257 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
8260 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
8263 @subsection Examples
8267 Apply horizontal and vertical deblocking, deringing and automatic
8268 brightness/contrast:
8274 Apply default filters without brightness/contrast correction:
8280 Apply default filters and temporal denoiser:
8282 pp=default/tmpnoise|1|2|3
8286 Apply deblocking on luminance only, and switch vertical deblocking on or off
8287 automatically depending on available CPU time:
8294 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
8295 similar to spp = 6 with 7 point DCT, where only the center sample is
8298 The filter accepts the following options:
8302 Force a constant quantization parameter. It accepts an integer in range
8303 0 to 63. If not set, the filter will use the QP from the video stream
8307 Set thresholding mode. Available modes are:
8311 Set hard thresholding.
8313 Set soft thresholding (better de-ringing effect, but likely blurrier).
8315 Set medium thresholding (good results, default).
8321 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
8322 Ratio) between two input videos.
8324 This filter takes in input two input videos, the first input is
8325 considered the "main" source and is passed unchanged to the
8326 output. The second input is used as a "reference" video for computing
8329 Both video inputs must have the same resolution and pixel format for
8330 this filter to work correctly. Also it assumes that both inputs
8331 have the same number of frames, which are compared one by one.
8333 The obtained average PSNR is printed through the logging system.
8335 The filter stores the accumulated MSE (mean squared error) of each
8336 frame, and at the end of the processing it is averaged across all frames
8337 equally, and the following formula is applied to obtain the PSNR:
8340 PSNR = 10*log10(MAX^2/MSE)
8343 Where MAX is the average of the maximum values of each component of the
8346 The description of the accepted parameters follows.
8350 If specified the filter will use the named file to save the PSNR of
8351 each individual frame.
8354 The file printed if @var{stats_file} is selected, contains a sequence of
8355 key/value pairs of the form @var{key}:@var{value} for each compared
8358 A description of each shown parameter follows:
8362 sequential number of the input frame, starting from 1
8365 Mean Square Error pixel-by-pixel average difference of the compared
8366 frames, averaged over all the image components.
8368 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
8369 Mean Square Error pixel-by-pixel average difference of the compared
8370 frames for the component specified by the suffix.
8372 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
8373 Peak Signal to Noise ratio of the compared frames for the component
8374 specified by the suffix.
8379 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
8380 [main][ref] psnr="stats_file=stats.log" [out]
8383 On this example the input file being processed is compared with the
8384 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
8385 is stored in @file{stats.log}.
8390 Pulldown reversal (inverse telecine) filter, capable of handling mixed
8391 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
8394 The pullup filter is designed to take advantage of future context in making
8395 its decisions. This filter is stateless in the sense that it does not lock
8396 onto a pattern to follow, but it instead looks forward to the following
8397 fields in order to identify matches and rebuild progressive frames.
8399 To produce content with an even framerate, insert the fps filter after
8400 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
8401 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
8403 The filter accepts the following options:
8410 These options set the amount of "junk" to ignore at the left, right, top, and
8411 bottom of the image, respectively. Left and right are in units of 8 pixels,
8412 while top and bottom are in units of 2 lines.
8413 The default is 8 pixels on each side.
8416 Set the strict breaks. Setting this option to 1 will reduce the chances of
8417 filter generating an occasional mismatched frame, but it may also cause an
8418 excessive number of frames to be dropped during high motion sequences.
8419 Conversely, setting it to -1 will make filter match fields more easily.
8420 This may help processing of video where there is slight blurring between
8421 the fields, but may also cause there to be interlaced frames in the output.
8422 Default value is @code{0}.
8425 Set the metric plane to use. It accepts the following values:
8431 Use chroma blue plane.
8434 Use chroma red plane.
8437 This option may be set to use chroma plane instead of the default luma plane
8438 for doing filter's computations. This may improve accuracy on very clean
8439 source material, but more likely will decrease accuracy, especially if there
8440 is chroma noise (rainbow effect) or any grayscale video.
8441 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
8442 load and make pullup usable in realtime on slow machines.
8445 For best results (without duplicated frames in the output file) it is
8446 necessary to change the output frame rate. For example, to inverse
8447 telecine NTSC input:
8449 ffmpeg -i input -vf pullup -r 24000/1001 ...
8454 Change video quantization parameters (QP).
8456 The filter accepts the following option:
8460 Set expression for quantization parameter.
8463 The expression is evaluated through the eval API and can contain, among others,
8464 the following constants:
8468 1 if index is not 129, 0 otherwise.
8471 Sequentional index starting from -129 to 128.
8474 @subsection Examples
8486 Flush video frames from internal cache of frames into a random order.
8487 No frame is discarded.
8488 Inspired by @ref{frei0r} nervous filter.
8492 Set size in number of frames of internal cache, in range from @code{2} to
8493 @code{512}. Default is @code{30}.
8496 Set seed for random number generator, must be an integer included between
8497 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
8498 less than @code{0}, the filter will try to use a good random seed on a
8502 @section removegrain
8504 The removegrain filter is a spatial denoiser for progressive video.
8508 Set mode for the first plane.
8511 Set mode for the second plane.
8514 Set mode for the third plane.
8517 Set mode for the fourth plane.
8520 Range of mode is from 0 to 24. Description of each mode follows:
8524 Leave input plane unchanged. Default.
8527 Clips the pixel with the minimum and maximum of the 8 neighbour pixels.
8530 Clips the pixel with the second minimum and maximum of the 8 neighbour pixels.
8533 Clips the pixel with the third minimum and maximum of the 8 neighbour pixels.
8536 Clips the pixel with the fourth minimum and maximum of the 8 neighbour pixels.
8537 This is equivalent to a median filter.
8540 Line-sensitive clipping giving the minimal change.
8543 Line-sensitive clipping, intermediate.
8546 Line-sensitive clipping, intermediate.
8549 Line-sensitive clipping, intermediate.
8552 Line-sensitive clipping on a line where the neighbours pixels are the closest.
8555 Replaces the target pixel with the closest neighbour.
8558 [1 2 1] horizontal and vertical kernel blur.
8564 Bob mode, interpolates top field from the line where the neighbours
8565 pixels are the closest.
8568 Bob mode, interpolates bottom field from the line where the neighbours
8569 pixels are the closest.
8572 Bob mode, interpolates top field. Same as 13 but with a more complicated
8573 interpolation formula.
8576 Bob mode, interpolates bottom field. Same as 14 but with a more complicated
8577 interpolation formula.
8580 Clips the pixel with the minimum and maximum of respectively the maximum and
8581 minimum of each pair of opposite neighbour pixels.
8584 Line-sensitive clipping using opposite neighbours whose greatest distance from
8585 the current pixel is minimal.
8588 Replaces the pixel with the average of its 8 neighbours.
8591 Averages the 9 pixels ([1 1 1] horizontal and vertical blur).
8594 Clips pixels using the averages of opposite neighbour.
8597 Same as mode 21 but simpler and faster.
8600 Small edge and halo removal, but reputed useless.
8608 Suppress a TV station logo, using an image file to determine which
8609 pixels comprise the logo. It works by filling in the pixels that
8610 comprise the logo with neighboring pixels.
8612 The filter accepts the following options:
8616 Set the filter bitmap file, which can be any image format supported by
8617 libavformat. The width and height of the image file must match those of the
8618 video stream being processed.
8621 Pixels in the provided bitmap image with a value of zero are not
8622 considered part of the logo, non-zero pixels are considered part of
8623 the logo. If you use white (255) for the logo and black (0) for the
8624 rest, you will be safe. For making the filter bitmap, it is
8625 recommended to take a screen capture of a black frame with the logo
8626 visible, and then using a threshold filter followed by the erode
8627 filter once or twice.
8629 If needed, little splotches can be fixed manually. Remember that if
8630 logo pixels are not covered, the filter quality will be much
8631 reduced. Marking too many pixels as part of the logo does not hurt as
8632 much, but it will increase the amount of blurring needed to cover over
8633 the image and will destroy more information than necessary, and extra
8634 pixels will slow things down on a large logo.
8636 @section repeatfields
8638 This filter uses the repeat_field flag from the Video ES headers and hard repeats
8639 fields based on its value.
8641 @section reverse, areverse
8645 Warning: This filter requires memory to buffer the entire clip, so trimming
8648 @subsection Examples
8652 Take the first 5 seconds of a clip, and reverse it.
8660 Rotate video by an arbitrary angle expressed in radians.
8662 The filter accepts the following options:
8664 A description of the optional parameters follows.
8667 Set an expression for the angle by which to rotate the input video
8668 clockwise, expressed as a number of radians. A negative value will
8669 result in a counter-clockwise rotation. By default it is set to "0".
8671 This expression is evaluated for each frame.
8674 Set the output width expression, default value is "iw".
8675 This expression is evaluated just once during configuration.
8678 Set the output height expression, default value is "ih".
8679 This expression is evaluated just once during configuration.
8682 Enable bilinear interpolation if set to 1, a value of 0 disables
8683 it. Default value is 1.
8686 Set the color used to fill the output area not covered by the rotated
8687 image. For the general syntax of this option, check the "Color" section in the
8688 ffmpeg-utils manual. If the special value "none" is selected then no
8689 background is printed (useful for example if the background is never shown).
8691 Default value is "black".
8694 The expressions for the angle and the output size can contain the
8695 following constants and functions:
8699 sequential number of the input frame, starting from 0. It is always NAN
8700 before the first frame is filtered.
8703 time in seconds of the input frame, it is set to 0 when the filter is
8704 configured. It is always NAN before the first frame is filtered.
8708 horizontal and vertical chroma subsample values. For example for the
8709 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
8713 the input video width and height
8717 the output width and height, that is the size of the padded area as
8718 specified by the @var{width} and @var{height} expressions
8722 the minimal width/height required for completely containing the input
8723 video rotated by @var{a} radians.
8725 These are only available when computing the @option{out_w} and
8726 @option{out_h} expressions.
8729 @subsection Examples
8733 Rotate the input by PI/6 radians clockwise:
8739 Rotate the input by PI/6 radians counter-clockwise:
8745 Rotate the input by 45 degrees clockwise:
8751 Apply a constant rotation with period T, starting from an angle of PI/3:
8753 rotate=PI/3+2*PI*t/T
8757 Make the input video rotation oscillating with a period of T
8758 seconds and an amplitude of A radians:
8760 rotate=A*sin(2*PI/T*t)
8764 Rotate the video, output size is chosen so that the whole rotating
8765 input video is always completely contained in the output:
8767 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
8771 Rotate the video, reduce the output size so that no background is ever
8774 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
8778 @subsection Commands
8780 The filter supports the following commands:
8784 Set the angle expression.
8785 The command accepts the same syntax of the corresponding option.
8787 If the specified expression is not valid, it is kept at its current
8793 Apply Shape Adaptive Blur.
8795 The filter accepts the following options:
8798 @item luma_radius, lr
8799 Set luma blur filter strength, must be a value in range 0.1-4.0, default
8800 value is 1.0. A greater value will result in a more blurred image, and
8801 in slower processing.
8803 @item luma_pre_filter_radius, lpfr
8804 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
8807 @item luma_strength, ls
8808 Set luma maximum difference between pixels to still be considered, must
8809 be a value in the 0.1-100.0 range, default value is 1.0.
8811 @item chroma_radius, cr
8812 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
8813 greater value will result in a more blurred image, and in slower
8816 @item chroma_pre_filter_radius, cpfr
8817 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
8819 @item chroma_strength, cs
8820 Set chroma maximum difference between pixels to still be considered,
8821 must be a value in the 0.1-100.0 range.
8824 Each chroma option value, if not explicitly specified, is set to the
8825 corresponding luma option value.
8830 Scale (resize) the input video, using the libswscale library.
8832 The scale filter forces the output display aspect ratio to be the same
8833 of the input, by changing the output sample aspect ratio.
8835 If the input image format is different from the format requested by
8836 the next filter, the scale filter will convert the input to the
8840 The filter accepts the following options, or any of the options
8841 supported by the libswscale scaler.
8843 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
8844 the complete list of scaler options.
8849 Set the output video dimension expression. Default value is the input
8852 If the value is 0, the input width is used for the output.
8854 If one of the values is -1, the scale filter will use a value that
8855 maintains the aspect ratio of the input image, calculated from the
8856 other specified dimension. If both of them are -1, the input size is
8859 If one of the values is -n with n > 1, the scale filter will also use a value
8860 that maintains the aspect ratio of the input image, calculated from the other
8861 specified dimension. After that it will, however, make sure that the calculated
8862 dimension is divisible by n and adjust the value if necessary.
8864 See below for the list of accepted constants for use in the dimension
8868 Set the interlacing mode. It accepts the following values:
8872 Force interlaced aware scaling.
8875 Do not apply interlaced scaling.
8878 Select interlaced aware scaling depending on whether the source frames
8879 are flagged as interlaced or not.
8882 Default value is @samp{0}.
8885 Set libswscale scaling flags. See
8886 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
8887 complete list of values. If not explicitly specified the filter applies
8891 Set the video size. For the syntax of this option, check the
8892 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
8894 @item in_color_matrix
8895 @item out_color_matrix
8896 Set in/output YCbCr color space type.
8898 This allows the autodetected value to be overridden as well as allows forcing
8899 a specific value used for the output and encoder.
8901 If not specified, the color space type depends on the pixel format.
8907 Choose automatically.
8910 Format conforming to International Telecommunication Union (ITU)
8911 Recommendation BT.709.
8914 Set color space conforming to the United States Federal Communications
8915 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
8918 Set color space conforming to:
8922 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
8925 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
8928 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
8933 Set color space conforming to SMPTE ST 240:1999.
8938 Set in/output YCbCr sample range.
8940 This allows the autodetected value to be overridden as well as allows forcing
8941 a specific value used for the output and encoder. If not specified, the
8942 range depends on the pixel format. Possible values:
8946 Choose automatically.
8949 Set full range (0-255 in case of 8-bit luma).
8952 Set "MPEG" range (16-235 in case of 8-bit luma).
8955 @item force_original_aspect_ratio
8956 Enable decreasing or increasing output video width or height if necessary to
8957 keep the original aspect ratio. Possible values:
8961 Scale the video as specified and disable this feature.
8964 The output video dimensions will automatically be decreased if needed.
8967 The output video dimensions will automatically be increased if needed.
8971 One useful instance of this option is that when you know a specific device's
8972 maximum allowed resolution, you can use this to limit the output video to
8973 that, while retaining the aspect ratio. For example, device A allows
8974 1280x720 playback, and your video is 1920x800. Using this option (set it to
8975 decrease) and specifying 1280x720 to the command line makes the output
8978 Please note that this is a different thing than specifying -1 for @option{w}
8979 or @option{h}, you still need to specify the output resolution for this option
8984 The values of the @option{w} and @option{h} options are expressions
8985 containing the following constants:
8990 The input width and height
8994 These are the same as @var{in_w} and @var{in_h}.
8998 The output (scaled) width and height
9002 These are the same as @var{out_w} and @var{out_h}
9005 The same as @var{iw} / @var{ih}
9008 input sample aspect ratio
9011 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
9015 horizontal and vertical input chroma subsample values. For example for the
9016 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9020 horizontal and vertical output chroma subsample values. For example for the
9021 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9024 @subsection Examples
9028 Scale the input video to a size of 200x100
9033 This is equivalent to:
9044 Specify a size abbreviation for the output size:
9049 which can also be written as:
9055 Scale the input to 2x:
9061 The above is the same as:
9067 Scale the input to 2x with forced interlaced scaling:
9069 scale=2*iw:2*ih:interl=1
9073 Scale the input to half size:
9079 Increase the width, and set the height to the same size:
9092 Increase the height, and set the width to 3/2 of the height:
9094 scale=w=3/2*oh:h=3/5*ih
9098 Increase the size, making the size a multiple of the chroma
9101 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
9105 Increase the width to a maximum of 500 pixels,
9106 keeping the same aspect ratio as the input:
9108 scale=w='min(500\, iw*3/2):h=-1'
9112 @subsection Commands
9114 This filter supports the following commands:
9118 Set the output video dimension expression.
9119 The command accepts the same syntax of the corresponding option.
9121 If the specified expression is not valid, it is kept at its current
9125 @section separatefields
9127 The @code{separatefields} takes a frame-based video input and splits
9128 each frame into its components fields, producing a new half height clip
9129 with twice the frame rate and twice the frame count.
9131 This filter use field-dominance information in frame to decide which
9132 of each pair of fields to place first in the output.
9133 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
9135 @section setdar, setsar
9137 The @code{setdar} filter sets the Display Aspect Ratio for the filter
9140 This is done by changing the specified Sample (aka Pixel) Aspect
9141 Ratio, according to the following equation:
9143 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
9146 Keep in mind that the @code{setdar} filter does not modify the pixel
9147 dimensions of the video frame. Also, the display aspect ratio set by
9148 this filter may be changed by later filters in the filterchain,
9149 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
9152 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
9153 the filter output video.
9155 Note that as a consequence of the application of this filter, the
9156 output display aspect ratio will change according to the equation
9159 Keep in mind that the sample aspect ratio set by the @code{setsar}
9160 filter may be changed by later filters in the filterchain, e.g. if
9161 another "setsar" or a "setdar" filter is applied.
9163 It accepts the following parameters:
9166 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
9167 Set the aspect ratio used by the filter.
9169 The parameter can be a floating point number string, an expression, or
9170 a string of the form @var{num}:@var{den}, where @var{num} and
9171 @var{den} are the numerator and denominator of the aspect ratio. If
9172 the parameter is not specified, it is assumed the value "0".
9173 In case the form "@var{num}:@var{den}" is used, the @code{:} character
9177 Set the maximum integer value to use for expressing numerator and
9178 denominator when reducing the expressed aspect ratio to a rational.
9179 Default value is @code{100}.
9183 The parameter @var{sar} is an expression containing
9184 the following constants:
9188 These are approximated values for the mathematical constants e
9189 (Euler's number), pi (Greek pi), and phi (the golden ratio).
9192 The input width and height.
9195 These are the same as @var{w} / @var{h}.
9198 The input sample aspect ratio.
9201 The input display aspect ratio. It is the same as
9202 (@var{w} / @var{h}) * @var{sar}.
9205 Horizontal and vertical chroma subsample values. For example, for the
9206 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9209 @subsection Examples
9214 To change the display aspect ratio to 16:9, specify one of the following:
9222 To change the sample aspect ratio to 10:11, specify:
9228 To set a display aspect ratio of 16:9, and specify a maximum integer value of
9229 1000 in the aspect ratio reduction, use the command:
9231 setdar=ratio=16/9:max=1000
9239 Force field for the output video frame.
9241 The @code{setfield} filter marks the interlace type field for the
9242 output frames. It does not change the input frame, but only sets the
9243 corresponding property, which affects how the frame is treated by
9244 following filters (e.g. @code{fieldorder} or @code{yadif}).
9246 The filter accepts the following options:
9251 Available values are:
9255 Keep the same field property.
9258 Mark the frame as bottom-field-first.
9261 Mark the frame as top-field-first.
9264 Mark the frame as progressive.
9270 Show a line containing various information for each input video frame.
9271 The input video is not modified.
9273 The shown line contains a sequence of key/value pairs of the form
9274 @var{key}:@var{value}.
9276 The following values are shown in the output:
9280 The (sequential) number of the input frame, starting from 0.
9283 The Presentation TimeStamp of the input frame, expressed as a number of
9284 time base units. The time base unit depends on the filter input pad.
9287 The Presentation TimeStamp of the input frame, expressed as a number of
9291 The position of the frame in the input stream, or -1 if this information is
9292 unavailable and/or meaningless (for example in case of synthetic video).
9295 The pixel format name.
9298 The sample aspect ratio of the input frame, expressed in the form
9299 @var{num}/@var{den}.
9302 The size of the input frame. For the syntax of this option, check the
9303 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
9306 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
9307 for bottom field first).
9310 This is 1 if the frame is a key frame, 0 otherwise.
9313 The picture type of the input frame ("I" for an I-frame, "P" for a
9314 P-frame, "B" for a B-frame, or "?" for an unknown type).
9315 Also refer to the documentation of the @code{AVPictureType} enum and of
9316 the @code{av_get_picture_type_char} function defined in
9317 @file{libavutil/avutil.h}.
9320 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
9322 @item plane_checksum
9323 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
9324 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
9327 @section showpalette
9329 Displays the 256 colors palette of each frame. This filter is only relevant for
9330 @var{pal8} pixel format frames.
9332 It accepts the following option:
9336 Set the size of the box used to represent one palette color entry. Default is
9337 @code{30} (for a @code{30x30} pixel box).
9340 @section shuffleplanes
9342 Reorder and/or duplicate video planes.
9344 It accepts the following parameters:
9349 The index of the input plane to be used as the first output plane.
9352 The index of the input plane to be used as the second output plane.
9355 The index of the input plane to be used as the third output plane.
9358 The index of the input plane to be used as the fourth output plane.
9362 The first plane has the index 0. The default is to keep the input unchanged.
9364 Swap the second and third planes of the input:
9366 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
9369 @anchor{signalstats}
9370 @section signalstats
9371 Evaluate various visual metrics that assist in determining issues associated
9372 with the digitization of analog video media.
9374 By default the filter will log these metadata values:
9378 Display the minimal Y value contained within the input frame. Expressed in
9382 Display the Y value at the 10% percentile within the input frame. Expressed in
9386 Display the average Y value within the input frame. Expressed in range of
9390 Display the Y value at the 90% percentile within the input frame. Expressed in
9394 Display the maximum Y value contained within the input frame. Expressed in
9398 Display the minimal U value contained within the input frame. Expressed in
9402 Display the U value at the 10% percentile within the input frame. Expressed in
9406 Display the average U value within the input frame. Expressed in range of
9410 Display the U value at the 90% percentile within the input frame. Expressed in
9414 Display the maximum U value contained within the input frame. Expressed in
9418 Display the minimal V value contained within the input frame. Expressed in
9422 Display the V value at the 10% percentile within the input frame. Expressed in
9426 Display the average V value within the input frame. Expressed in range of
9430 Display the V value at the 90% percentile within the input frame. Expressed in
9434 Display the maximum V value contained within the input frame. Expressed in
9438 Display the minimal saturation value contained within the input frame.
9439 Expressed in range of [0-~181.02].
9442 Display the saturation value at the 10% percentile within the input frame.
9443 Expressed in range of [0-~181.02].
9446 Display the average saturation value within the input frame. Expressed in range
9450 Display the saturation value at the 90% percentile within the input frame.
9451 Expressed in range of [0-~181.02].
9454 Display the maximum saturation value contained within the input frame.
9455 Expressed in range of [0-~181.02].
9458 Display the median value for hue within the input frame. Expressed in range of
9462 Display the average value for hue within the input frame. Expressed in range of
9466 Display the average of sample value difference between all values of the Y
9467 plane in the current frame and corresponding values of the previous input frame.
9468 Expressed in range of [0-255].
9471 Display the average of sample value difference between all values of the U
9472 plane in the current frame and corresponding values of the previous input frame.
9473 Expressed in range of [0-255].
9476 Display the average of sample value difference between all values of the V
9477 plane in the current frame and corresponding values of the previous input frame.
9478 Expressed in range of [0-255].
9481 The filter accepts the following options:
9487 @option{stat} specify an additional form of image analysis.
9488 @option{out} output video with the specified type of pixel highlighted.
9490 Both options accept the following values:
9494 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
9495 unlike the neighboring pixels of the same field. Examples of temporal outliers
9496 include the results of video dropouts, head clogs, or tape tracking issues.
9499 Identify @var{vertical line repetition}. Vertical line repetition includes
9500 similar rows of pixels within a frame. In born-digital video vertical line
9501 repetition is common, but this pattern is uncommon in video digitized from an
9502 analog source. When it occurs in video that results from the digitization of an
9503 analog source it can indicate concealment from a dropout compensator.
9506 Identify pixels that fall outside of legal broadcast range.
9510 Set the highlight color for the @option{out} option. The default color is
9514 @subsection Examples
9518 Output data of various video metrics:
9520 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
9524 Output specific data about the minimum and maximum values of the Y plane per frame:
9526 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
9530 Playback video while highlighting pixels that are outside of broadcast range in red.
9532 ffplay example.mov -vf signalstats="out=brng:color=red"
9536 Playback video with signalstats metadata drawn over the frame.
9538 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
9541 The contents of signalstat_drawtext.txt used in the command are:
9544 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
9545 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
9546 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
9547 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
9555 Blur the input video without impacting the outlines.
9557 It accepts the following options:
9560 @item luma_radius, lr
9561 Set the luma radius. The option value must be a float number in
9562 the range [0.1,5.0] that specifies the variance of the gaussian filter
9563 used to blur the image (slower if larger). Default value is 1.0.
9565 @item luma_strength, ls
9566 Set the luma strength. The option value must be a float number
9567 in the range [-1.0,1.0] that configures the blurring. A value included
9568 in [0.0,1.0] will blur the image whereas a value included in
9569 [-1.0,0.0] will sharpen the image. Default value is 1.0.
9571 @item luma_threshold, lt
9572 Set the luma threshold used as a coefficient to determine
9573 whether a pixel should be blurred or not. The option value must be an
9574 integer in the range [-30,30]. A value of 0 will filter all the image,
9575 a value included in [0,30] will filter flat areas and a value included
9576 in [-30,0] will filter edges. Default value is 0.
9578 @item chroma_radius, cr
9579 Set the chroma radius. The option value must be a float number in
9580 the range [0.1,5.0] that specifies the variance of the gaussian filter
9581 used to blur the image (slower if larger). Default value is 1.0.
9583 @item chroma_strength, cs
9584 Set the chroma strength. The option value must be a float number
9585 in the range [-1.0,1.0] that configures the blurring. A value included
9586 in [0.0,1.0] will blur the image whereas a value included in
9587 [-1.0,0.0] will sharpen the image. Default value is 1.0.
9589 @item chroma_threshold, ct
9590 Set the chroma threshold used as a coefficient to determine
9591 whether a pixel should be blurred or not. The option value must be an
9592 integer in the range [-30,30]. A value of 0 will filter all the image,
9593 a value included in [0,30] will filter flat areas and a value included
9594 in [-30,0] will filter edges. Default value is 0.
9597 If a chroma option is not explicitly set, the corresponding luma value
9602 Obtain the SSIM (Structural SImilarity Metric) between two input videos.
9604 This filter takes in input two input videos, the first input is
9605 considered the "main" source and is passed unchanged to the
9606 output. The second input is used as a "reference" video for computing
9609 Both video inputs must have the same resolution and pixel format for
9610 this filter to work correctly. Also it assumes that both inputs
9611 have the same number of frames, which are compared one by one.
9613 The filter stores the calculated SSIM of each frame.
9615 The description of the accepted parameters follows.
9619 If specified the filter will use the named file to save the SSIM of
9620 each individual frame.
9623 The file printed if @var{stats_file} is selected, contains a sequence of
9624 key/value pairs of the form @var{key}:@var{value} for each compared
9627 A description of each shown parameter follows:
9631 sequential number of the input frame, starting from 1
9633 @item Y, U, V, R, G, B
9634 SSIM of the compared frames for the component specified by the suffix.
9637 SSIM of the compared frames for the whole frame.
9640 Same as above but in dB representation.
9645 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
9646 [main][ref] ssim="stats_file=stats.log" [out]
9649 On this example the input file being processed is compared with the
9650 reference file @file{ref_movie.mpg}. The SSIM of each individual frame
9651 is stored in @file{stats.log}.
9653 Another example with both psnr and ssim at same time:
9655 ffmpeg -i main.mpg -i ref.mpg -lavfi "ssim;[0:v][1:v]psnr" -f null -
9660 Convert between different stereoscopic image formats.
9662 The filters accept the following options:
9666 Set stereoscopic image format of input.
9668 Available values for input image formats are:
9671 side by side parallel (left eye left, right eye right)
9674 side by side crosseye (right eye left, left eye right)
9677 side by side parallel with half width resolution
9678 (left eye left, right eye right)
9681 side by side crosseye with half width resolution
9682 (right eye left, left eye right)
9685 above-below (left eye above, right eye below)
9688 above-below (right eye above, left eye below)
9691 above-below with half height resolution
9692 (left eye above, right eye below)
9695 above-below with half height resolution
9696 (right eye above, left eye below)
9699 alternating frames (left eye first, right eye second)
9702 alternating frames (right eye first, left eye second)
9704 Default value is @samp{sbsl}.
9708 Set stereoscopic image format of output.
9710 Available values for output image formats are all the input formats as well as:
9713 anaglyph red/blue gray
9714 (red filter on left eye, blue filter on right eye)
9717 anaglyph red/green gray
9718 (red filter on left eye, green filter on right eye)
9721 anaglyph red/cyan gray
9722 (red filter on left eye, cyan filter on right eye)
9725 anaglyph red/cyan half colored
9726 (red filter on left eye, cyan filter on right eye)
9729 anaglyph red/cyan color
9730 (red filter on left eye, cyan filter on right eye)
9733 anaglyph red/cyan color optimized with the least squares projection of dubois
9734 (red filter on left eye, cyan filter on right eye)
9737 anaglyph green/magenta gray
9738 (green filter on left eye, magenta filter on right eye)
9741 anaglyph green/magenta half colored
9742 (green filter on left eye, magenta filter on right eye)
9745 anaglyph green/magenta colored
9746 (green filter on left eye, magenta filter on right eye)
9749 anaglyph green/magenta color optimized with the least squares projection of dubois
9750 (green filter on left eye, magenta filter on right eye)
9753 anaglyph yellow/blue gray
9754 (yellow filter on left eye, blue filter on right eye)
9757 anaglyph yellow/blue half colored
9758 (yellow filter on left eye, blue filter on right eye)
9761 anaglyph yellow/blue colored
9762 (yellow filter on left eye, blue filter on right eye)
9765 anaglyph yellow/blue color optimized with the least squares projection of dubois
9766 (yellow filter on left eye, blue filter on right eye)
9769 interleaved rows (left eye has top row, right eye starts on next row)
9772 interleaved rows (right eye has top row, left eye starts on next row)
9775 mono output (left eye only)
9778 mono output (right eye only)
9781 Default value is @samp{arcd}.
9784 @subsection Examples
9788 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
9794 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
9803 Apply a simple postprocessing filter that compresses and decompresses the image
9804 at several (or - in the case of @option{quality} level @code{6} - all) shifts
9805 and average the results.
9807 The filter accepts the following options:
9811 Set quality. This option defines the number of levels for averaging. It accepts
9812 an integer in the range 0-6. If set to @code{0}, the filter will have no
9813 effect. A value of @code{6} means the higher quality. For each increment of
9814 that value the speed drops by a factor of approximately 2. Default value is
9818 Force a constant quantization parameter. If not set, the filter will use the QP
9819 from the video stream (if available).
9822 Set thresholding mode. Available modes are:
9826 Set hard thresholding (default).
9828 Set soft thresholding (better de-ringing effect, but likely blurrier).
9832 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
9833 option may cause flicker since the B-Frames have often larger QP. Default is
9834 @code{0} (not enabled).
9840 Draw subtitles on top of input video using the libass library.
9842 To enable compilation of this filter you need to configure FFmpeg with
9843 @code{--enable-libass}. This filter also requires a build with libavcodec and
9844 libavformat to convert the passed subtitles file to ASS (Advanced Substation
9845 Alpha) subtitles format.
9847 The filter accepts the following options:
9851 Set the filename of the subtitle file to read. It must be specified.
9854 Specify the size of the original video, the video for which the ASS file
9855 was composed. For the syntax of this option, check the
9856 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
9857 Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
9858 correctly scale the fonts if the aspect ratio has been changed.
9861 Set subtitles input character encoding. @code{subtitles} filter only. Only
9862 useful if not UTF-8.
9864 @item stream_index, si
9865 Set subtitles stream index. @code{subtitles} filter only.
9868 Override default style or script info parameters of the subtitles. It accepts a
9869 string containing ASS style format @code{KEY=VALUE} couples separated by ",".
9872 If the first key is not specified, it is assumed that the first value
9873 specifies the @option{filename}.
9875 For example, to render the file @file{sub.srt} on top of the input
9876 video, use the command:
9881 which is equivalent to:
9883 subtitles=filename=sub.srt
9886 To render the default subtitles stream from file @file{video.mkv}, use:
9891 To render the second subtitles stream from that file, use:
9893 subtitles=video.mkv:si=1
9896 To make the subtitles stream from @file{sub.srt} appear in transparent green
9897 @code{DejaVu Serif}, use:
9899 subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'
9904 Scale the input by 2x and smooth using the Super2xSaI (Scale and
9905 Interpolate) pixel art scaling algorithm.
9907 Useful for enlarging pixel art images without reducing sharpness.
9914 Apply telecine process to the video.
9916 This filter accepts the following options:
9925 The default value is @code{top}.
9929 A string of numbers representing the pulldown pattern you wish to apply.
9930 The default value is @code{23}.
9934 Some typical patterns:
9939 24p: 2332 (preferred)
9946 24p: 222222222223 ("Euro pulldown")
9952 Select the most representative frame in a given sequence of consecutive frames.
9954 The filter accepts the following options:
9958 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
9959 will pick one of them, and then handle the next batch of @var{n} frames until
9960 the end. Default is @code{100}.
9963 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
9964 value will result in a higher memory usage, so a high value is not recommended.
9966 @subsection Examples
9970 Extract one picture each 50 frames:
9976 Complete example of a thumbnail creation with @command{ffmpeg}:
9978 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
9984 Tile several successive frames together.
9986 The filter accepts the following options:
9991 Set the grid size (i.e. the number of lines and columns). For the syntax of
9992 this option, check the
9993 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
9996 Set the maximum number of frames to render in the given area. It must be less
9997 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
9998 the area will be used.
10001 Set the outer border margin in pixels.
10004 Set the inner border thickness (i.e. the number of pixels between frames). For
10005 more advanced padding options (such as having different values for the edges),
10006 refer to the pad video filter.
10009 Specify the color of the unused area. For the syntax of this option, check the
10010 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
10014 @subsection Examples
10018 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
10020 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
10022 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
10023 duplicating each output frame to accommodate the originally detected frame
10027 Display @code{5} pictures in an area of @code{3x2} frames,
10028 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
10029 mixed flat and named options:
10031 tile=3x2:nb_frames=5:padding=7:margin=2
10035 @section tinterlace
10037 Perform various types of temporal field interlacing.
10039 Frames are counted starting from 1, so the first input frame is
10042 The filter accepts the following options:
10047 Specify the mode of the interlacing. This option can also be specified
10048 as a value alone. See below for a list of values for this option.
10050 Available values are:
10054 Move odd frames into the upper field, even into the lower field,
10055 generating a double height frame at half frame rate.
10059 Frame 1 Frame 2 Frame 3 Frame 4
10061 11111 22222 33333 44444
10062 11111 22222 33333 44444
10063 11111 22222 33333 44444
10064 11111 22222 33333 44444
10078 Only output even frames, odd frames are dropped, generating a frame with
10079 unchanged height at half frame rate.
10084 Frame 1 Frame 2 Frame 3 Frame 4
10086 11111 22222 33333 44444
10087 11111 22222 33333 44444
10088 11111 22222 33333 44444
10089 11111 22222 33333 44444
10099 Only output odd frames, even frames are dropped, generating a frame with
10100 unchanged height at half frame rate.
10105 Frame 1 Frame 2 Frame 3 Frame 4
10107 11111 22222 33333 44444
10108 11111 22222 33333 44444
10109 11111 22222 33333 44444
10110 11111 22222 33333 44444
10120 Expand each frame to full height, but pad alternate lines with black,
10121 generating a frame with double height at the same input frame rate.
10126 Frame 1 Frame 2 Frame 3 Frame 4
10128 11111 22222 33333 44444
10129 11111 22222 33333 44444
10130 11111 22222 33333 44444
10131 11111 22222 33333 44444
10134 11111 ..... 33333 .....
10135 ..... 22222 ..... 44444
10136 11111 ..... 33333 .....
10137 ..... 22222 ..... 44444
10138 11111 ..... 33333 .....
10139 ..... 22222 ..... 44444
10140 11111 ..... 33333 .....
10141 ..... 22222 ..... 44444
10145 @item interleave_top, 4
10146 Interleave the upper field from odd frames with the lower field from
10147 even frames, generating a frame with unchanged height at half frame rate.
10152 Frame 1 Frame 2 Frame 3 Frame 4
10154 11111<- 22222 33333<- 44444
10155 11111 22222<- 33333 44444<-
10156 11111<- 22222 33333<- 44444
10157 11111 22222<- 33333 44444<-
10167 @item interleave_bottom, 5
10168 Interleave the lower field from odd frames with the upper field from
10169 even frames, generating a frame with unchanged height at half frame rate.
10174 Frame 1 Frame 2 Frame 3 Frame 4
10176 11111 22222<- 33333 44444<-
10177 11111<- 22222 33333<- 44444
10178 11111 22222<- 33333 44444<-
10179 11111<- 22222 33333<- 44444
10189 @item interlacex2, 6
10190 Double frame rate with unchanged height. Frames are inserted each
10191 containing the second temporal field from the previous input frame and
10192 the first temporal field from the next input frame. This mode relies on
10193 the top_field_first flag. Useful for interlaced video displays with no
10194 field synchronisation.
10199 Frame 1 Frame 2 Frame 3 Frame 4
10201 11111 22222 33333 44444
10202 11111 22222 33333 44444
10203 11111 22222 33333 44444
10204 11111 22222 33333 44444
10207 11111 22222 22222 33333 33333 44444 44444
10208 11111 11111 22222 22222 33333 33333 44444
10209 11111 22222 22222 33333 33333 44444 44444
10210 11111 11111 22222 22222 33333 33333 44444
10216 Numeric values are deprecated but are accepted for backward
10217 compatibility reasons.
10219 Default mode is @code{merge}.
10222 Specify flags influencing the filter process.
10224 Available value for @var{flags} is:
10227 @item low_pass_filter, vlfp
10228 Enable vertical low-pass filtering in the filter.
10229 Vertical low-pass filtering is required when creating an interlaced
10230 destination from a progressive source which contains high-frequency
10231 vertical detail. Filtering will reduce interlace 'twitter' and Moire
10234 Vertical low-pass filtering can only be enabled for @option{mode}
10235 @var{interleave_top} and @var{interleave_bottom}.
10242 Transpose rows with columns in the input video and optionally flip it.
10244 It accepts the following parameters:
10249 Specify the transposition direction.
10251 Can assume the following values:
10253 @item 0, 4, cclock_flip
10254 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
10262 Rotate by 90 degrees clockwise, that is:
10270 Rotate by 90 degrees counterclockwise, that is:
10277 @item 3, 7, clock_flip
10278 Rotate by 90 degrees clockwise and vertically flip, that is:
10286 For values between 4-7, the transposition is only done if the input
10287 video geometry is portrait and not landscape. These values are
10288 deprecated, the @code{passthrough} option should be used instead.
10290 Numerical values are deprecated, and should be dropped in favor of
10291 symbolic constants.
10294 Do not apply the transposition if the input geometry matches the one
10295 specified by the specified value. It accepts the following values:
10298 Always apply transposition.
10300 Preserve portrait geometry (when @var{height} >= @var{width}).
10302 Preserve landscape geometry (when @var{width} >= @var{height}).
10305 Default value is @code{none}.
10308 For example to rotate by 90 degrees clockwise and preserve portrait
10311 transpose=dir=1:passthrough=portrait
10314 The command above can also be specified as:
10316 transpose=1:portrait
10320 Trim the input so that the output contains one continuous subpart of the input.
10322 It accepts the following parameters:
10325 Specify the time of the start of the kept section, i.e. the frame with the
10326 timestamp @var{start} will be the first frame in the output.
10329 Specify the time of the first frame that will be dropped, i.e. the frame
10330 immediately preceding the one with the timestamp @var{end} will be the last
10331 frame in the output.
10334 This is the same as @var{start}, except this option sets the start timestamp
10335 in timebase units instead of seconds.
10338 This is the same as @var{end}, except this option sets the end timestamp
10339 in timebase units instead of seconds.
10342 The maximum duration of the output in seconds.
10345 The number of the first frame that should be passed to the output.
10348 The number of the first frame that should be dropped.
10351 @option{start}, @option{end}, and @option{duration} are expressed as time
10352 duration specifications; see
10353 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
10354 for the accepted syntax.
10356 Note that the first two sets of the start/end options and the @option{duration}
10357 option look at the frame timestamp, while the _frame variants simply count the
10358 frames that pass through the filter. Also note that this filter does not modify
10359 the timestamps. If you wish for the output timestamps to start at zero, insert a
10360 setpts filter after the trim filter.
10362 If multiple start or end options are set, this filter tries to be greedy and
10363 keep all the frames that match at least one of the specified constraints. To keep
10364 only the part that matches all the constraints at once, chain multiple trim
10367 The defaults are such that all the input is kept. So it is possible to set e.g.
10368 just the end values to keep everything before the specified time.
10373 Drop everything except the second minute of input:
10375 ffmpeg -i INPUT -vf trim=60:120
10379 Keep only the first second:
10381 ffmpeg -i INPUT -vf trim=duration=1
10390 Sharpen or blur the input video.
10392 It accepts the following parameters:
10395 @item luma_msize_x, lx
10396 Set the luma matrix horizontal size. It must be an odd integer between
10397 3 and 63. The default value is 5.
10399 @item luma_msize_y, ly
10400 Set the luma matrix vertical size. It must be an odd integer between 3
10401 and 63. The default value is 5.
10403 @item luma_amount, la
10404 Set the luma effect strength. It must be a floating point number, reasonable
10405 values lay between -1.5 and 1.5.
10407 Negative values will blur the input video, while positive values will
10408 sharpen it, a value of zero will disable the effect.
10410 Default value is 1.0.
10412 @item chroma_msize_x, cx
10413 Set the chroma matrix horizontal size. It must be an odd integer
10414 between 3 and 63. The default value is 5.
10416 @item chroma_msize_y, cy
10417 Set the chroma matrix vertical size. It must be an odd integer
10418 between 3 and 63. The default value is 5.
10420 @item chroma_amount, ca
10421 Set the chroma effect strength. It must be a floating point number, reasonable
10422 values lay between -1.5 and 1.5.
10424 Negative values will blur the input video, while positive values will
10425 sharpen it, a value of zero will disable the effect.
10427 Default value is 0.0.
10430 If set to 1, specify using OpenCL capabilities, only available if
10431 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
10435 All parameters are optional and default to the equivalent of the
10436 string '5:5:1.0:5:5:0.0'.
10438 @subsection Examples
10442 Apply strong luma sharpen effect:
10444 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
10448 Apply a strong blur of both luma and chroma parameters:
10450 unsharp=7:7:-2:7:7:-2
10456 Apply ultra slow/simple postprocessing filter that compresses and decompresses
10457 the image at several (or - in the case of @option{quality} level @code{8} - all)
10458 shifts and average the results.
10460 The way this differs from the behavior of spp is that uspp actually encodes &
10461 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
10462 DCT similar to MJPEG.
10464 The filter accepts the following options:
10468 Set quality. This option defines the number of levels for averaging. It accepts
10469 an integer in the range 0-8. If set to @code{0}, the filter will have no
10470 effect. A value of @code{8} means the higher quality. For each increment of
10471 that value the speed drops by a factor of approximately 2. Default value is
10475 Force a constant quantization parameter. If not set, the filter will use the QP
10476 from the video stream (if available).
10479 @anchor{vidstabdetect}
10480 @section vidstabdetect
10482 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
10483 @ref{vidstabtransform} for pass 2.
10485 This filter generates a file with relative translation and rotation
10486 transform information about subsequent frames, which is then used by
10487 the @ref{vidstabtransform} filter.
10489 To enable compilation of this filter you need to configure FFmpeg with
10490 @code{--enable-libvidstab}.
10492 This filter accepts the following options:
10496 Set the path to the file used to write the transforms information.
10497 Default value is @file{transforms.trf}.
10500 Set how shaky the video is and how quick the camera is. It accepts an
10501 integer in the range 1-10, a value of 1 means little shakiness, a
10502 value of 10 means strong shakiness. Default value is 5.
10505 Set the accuracy of the detection process. It must be a value in the
10506 range 1-15. A value of 1 means low accuracy, a value of 15 means high
10507 accuracy. Default value is 15.
10510 Set stepsize of the search process. The region around minimum is
10511 scanned with 1 pixel resolution. Default value is 6.
10514 Set minimum contrast. Below this value a local measurement field is
10515 discarded. Must be a floating point value in the range 0-1. Default
10519 Set reference frame number for tripod mode.
10521 If enabled, the motion of the frames is compared to a reference frame
10522 in the filtered stream, identified by the specified number. The idea
10523 is to compensate all movements in a more-or-less static scene and keep
10524 the camera view absolutely still.
10526 If set to 0, it is disabled. The frames are counted starting from 1.
10529 Show fields and transforms in the resulting frames. It accepts an
10530 integer in the range 0-2. Default value is 0, which disables any
10534 @subsection Examples
10538 Use default values:
10544 Analyze strongly shaky movie and put the results in file
10545 @file{mytransforms.trf}:
10547 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
10551 Visualize the result of internal transformations in the resulting
10554 vidstabdetect=show=1
10558 Analyze a video with medium shakiness using @command{ffmpeg}:
10560 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
10564 @anchor{vidstabtransform}
10565 @section vidstabtransform
10567 Video stabilization/deshaking: pass 2 of 2,
10568 see @ref{vidstabdetect} for pass 1.
10570 Read a file with transform information for each frame and
10571 apply/compensate them. Together with the @ref{vidstabdetect}
10572 filter this can be used to deshake videos. See also
10573 @url{http://public.hronopik.de/vid.stab}. It is important to also use
10574 the @ref{unsharp} filter, see below.
10576 To enable compilation of this filter you need to configure FFmpeg with
10577 @code{--enable-libvidstab}.
10579 @subsection Options
10583 Set path to the file used to read the transforms. Default value is
10584 @file{transforms.trf}.
10587 Set the number of frames (value*2 + 1) used for lowpass filtering the
10588 camera movements. Default value is 10.
10590 For example a number of 10 means that 21 frames are used (10 in the
10591 past and 10 in the future) to smoothen the motion in the video. A
10592 larger value leads to a smoother video, but limits the acceleration of
10593 the camera (pan/tilt movements). 0 is a special case where a static
10594 camera is simulated.
10597 Set the camera path optimization algorithm.
10599 Accepted values are:
10602 gaussian kernel low-pass filter on camera motion (default)
10604 averaging on transformations
10608 Set maximal number of pixels to translate frames. Default value is -1,
10612 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
10613 value is -1, meaning no limit.
10616 Specify how to deal with borders that may be visible due to movement
10619 Available values are:
10622 keep image information from previous frame (default)
10624 fill the border black
10628 Invert transforms if set to 1. Default value is 0.
10631 Consider transforms as relative to previous frame if set to 1,
10632 absolute if set to 0. Default value is 0.
10635 Set percentage to zoom. A positive value will result in a zoom-in
10636 effect, a negative value in a zoom-out effect. Default value is 0 (no
10640 Set optimal zooming to avoid borders.
10642 Accepted values are:
10647 optimal static zoom value is determined (only very strong movements
10648 will lead to visible borders) (default)
10650 optimal adaptive zoom value is determined (no borders will be
10651 visible), see @option{zoomspeed}
10654 Note that the value given at zoom is added to the one calculated here.
10657 Set percent to zoom maximally each frame (enabled when
10658 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
10662 Specify type of interpolation.
10664 Available values are:
10669 linear only horizontal
10671 linear in both directions (default)
10673 cubic in both directions (slow)
10677 Enable virtual tripod mode if set to 1, which is equivalent to
10678 @code{relative=0:smoothing=0}. Default value is 0.
10680 Use also @code{tripod} option of @ref{vidstabdetect}.
10683 Increase log verbosity if set to 1. Also the detected global motions
10684 are written to the temporary file @file{global_motions.trf}. Default
10688 @subsection Examples
10692 Use @command{ffmpeg} for a typical stabilization with default values:
10694 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
10697 Note the use of the @ref{unsharp} filter which is always recommended.
10700 Zoom in a bit more and load transform data from a given file:
10702 vidstabtransform=zoom=5:input="mytransforms.trf"
10706 Smoothen the video even more:
10708 vidstabtransform=smoothing=30
10714 Flip the input video vertically.
10716 For example, to vertically flip a video with @command{ffmpeg}:
10718 ffmpeg -i in.avi -vf "vflip" out.avi
10724 Make or reverse a natural vignetting effect.
10726 The filter accepts the following options:
10730 Set lens angle expression as a number of radians.
10732 The value is clipped in the @code{[0,PI/2]} range.
10734 Default value: @code{"PI/5"}
10738 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
10742 Set forward/backward mode.
10744 Available modes are:
10747 The larger the distance from the central point, the darker the image becomes.
10750 The larger the distance from the central point, the brighter the image becomes.
10751 This can be used to reverse a vignette effect, though there is no automatic
10752 detection to extract the lens @option{angle} and other settings (yet). It can
10753 also be used to create a burning effect.
10756 Default value is @samp{forward}.
10759 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
10761 It accepts the following values:
10764 Evaluate expressions only once during the filter initialization.
10767 Evaluate expressions for each incoming frame. This is way slower than the
10768 @samp{init} mode since it requires all the scalers to be re-computed, but it
10769 allows advanced dynamic expressions.
10772 Default value is @samp{init}.
10775 Set dithering to reduce the circular banding effects. Default is @code{1}
10779 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
10780 Setting this value to the SAR of the input will make a rectangular vignetting
10781 following the dimensions of the video.
10783 Default is @code{1/1}.
10786 @subsection Expressions
10788 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
10789 following parameters.
10794 input width and height
10797 the number of input frame, starting from 0
10800 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
10801 @var{TB} units, NAN if undefined
10804 frame rate of the input video, NAN if the input frame rate is unknown
10807 the PTS (Presentation TimeStamp) of the filtered video frame,
10808 expressed in seconds, NAN if undefined
10811 time base of the input video
10815 @subsection Examples
10819 Apply simple strong vignetting effect:
10825 Make a flickering vignetting:
10827 vignette='PI/4+random(1)*PI/50':eval=frame
10834 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
10835 Deinterlacing Filter").
10837 Based on the process described by Martin Weston for BBC R&D, and
10838 implemented based on the de-interlace algorithm written by Jim
10839 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
10840 uses filter coefficients calculated by BBC R&D.
10842 There are two sets of filter coefficients, so called "simple":
10843 and "complex". Which set of filter coefficients is used can
10844 be set by passing an optional parameter:
10848 Set the interlacing filter coefficients. Accepts one of the following values:
10852 Simple filter coefficient set.
10854 More-complex filter coefficient set.
10856 Default value is @samp{complex}.
10859 Specify which frames to deinterlace. Accept one of the following values:
10863 Deinterlace all frames,
10865 Only deinterlace frames marked as interlaced.
10868 Default value is @samp{all}.
10872 Apply the xBR high-quality magnification filter which is designed for pixel
10873 art. It follows a set of edge-detection rules, see
10874 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
10876 It accepts the following option:
10880 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
10881 @code{3xBR} and @code{4} for @code{4xBR}.
10882 Default is @code{3}.
10888 Deinterlace the input video ("yadif" means "yet another deinterlacing
10891 It accepts the following parameters:
10897 The interlacing mode to adopt. It accepts one of the following values:
10900 @item 0, send_frame
10901 Output one frame for each frame.
10902 @item 1, send_field
10903 Output one frame for each field.
10904 @item 2, send_frame_nospatial
10905 Like @code{send_frame}, but it skips the spatial interlacing check.
10906 @item 3, send_field_nospatial
10907 Like @code{send_field}, but it skips the spatial interlacing check.
10910 The default value is @code{send_frame}.
10913 The picture field parity assumed for the input interlaced video. It accepts one
10914 of the following values:
10918 Assume the top field is first.
10920 Assume the bottom field is first.
10922 Enable automatic detection of field parity.
10925 The default value is @code{auto}.
10926 If the interlacing is unknown or the decoder does not export this information,
10927 top field first will be assumed.
10930 Specify which frames to deinterlace. Accept one of the following
10935 Deinterlace all frames.
10936 @item 1, interlaced
10937 Only deinterlace frames marked as interlaced.
10940 The default value is @code{all}.
10945 Apply Zoom & Pan effect.
10947 This filter accepts the following options:
10951 Set the zoom expression. Default is 1.
10955 Set the x and y expression. Default is 0.
10958 Set the duration expression in number of frames.
10959 This sets for how many number of frames effect will last for
10960 single input image.
10963 Set the output image size, default is 'hd720'.
10966 Each expression can contain the following constants:
10985 Output frame count.
10989 Last calculated 'x' and 'y' position from 'x' and 'y' expression
10990 for current input frame.
10994 'x' and 'y' of last output frame of previous input frame or 0 when there was
10995 not yet such frame (first input frame).
10998 Last calculated zoom from 'z' expression for current input frame.
11001 Last calculated zoom of last output frame of previous input frame.
11004 Number of output frames for current input frame. Calculated from 'd' expression
11005 for each input frame.
11008 number of output frames created for previous input frame
11011 Rational number: input width / input height
11014 sample aspect ratio
11017 display aspect ratio
11021 @subsection Examples
11025 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
11027 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
11031 Zoom-in up to 1.5 and pan always at center of picture:
11033 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
11037 @c man end VIDEO FILTERS
11039 @chapter Video Sources
11040 @c man begin VIDEO SOURCES
11042 Below is a description of the currently available video sources.
11046 Buffer video frames, and make them available to the filter chain.
11048 This source is mainly intended for a programmatic use, in particular
11049 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
11051 It accepts the following parameters:
11056 Specify the size (width and height) of the buffered video frames. For the
11057 syntax of this option, check the
11058 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11061 The input video width.
11064 The input video height.
11067 A string representing the pixel format of the buffered video frames.
11068 It may be a number corresponding to a pixel format, or a pixel format
11072 Specify the timebase assumed by the timestamps of the buffered frames.
11075 Specify the frame rate expected for the video stream.
11077 @item pixel_aspect, sar
11078 The sample (pixel) aspect ratio of the input video.
11081 Specify the optional parameters to be used for the scale filter which
11082 is automatically inserted when an input change is detected in the
11083 input size or format.
11088 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
11091 will instruct the source to accept video frames with size 320x240 and
11092 with format "yuv410p", assuming 1/24 as the timestamps timebase and
11093 square pixels (1:1 sample aspect ratio).
11094 Since the pixel format with name "yuv410p" corresponds to the number 6
11095 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
11096 this example corresponds to:
11098 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
11101 Alternatively, the options can be specified as a flat string, but this
11102 syntax is deprecated:
11104 @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}]
11108 Create a pattern generated by an elementary cellular automaton.
11110 The initial state of the cellular automaton can be defined through the
11111 @option{filename}, and @option{pattern} options. If such options are
11112 not specified an initial state is created randomly.
11114 At each new frame a new row in the video is filled with the result of
11115 the cellular automaton next generation. The behavior when the whole
11116 frame is filled is defined by the @option{scroll} option.
11118 This source accepts the following options:
11122 Read the initial cellular automaton state, i.e. the starting row, from
11123 the specified file.
11124 In the file, each non-whitespace character is considered an alive
11125 cell, a newline will terminate the row, and further characters in the
11126 file will be ignored.
11129 Read the initial cellular automaton state, i.e. the starting row, from
11130 the specified string.
11132 Each non-whitespace character in the string is considered an alive
11133 cell, a newline will terminate the row, and further characters in the
11134 string will be ignored.
11137 Set the video rate, that is the number of frames generated per second.
11140 @item random_fill_ratio, ratio
11141 Set the random fill ratio for the initial cellular automaton row. It
11142 is a floating point number value ranging from 0 to 1, defaults to
11145 This option is ignored when a file or a pattern is specified.
11147 @item random_seed, seed
11148 Set the seed for filling randomly the initial row, must be an integer
11149 included between 0 and UINT32_MAX. If not specified, or if explicitly
11150 set to -1, the filter will try to use a good random seed on a best
11154 Set the cellular automaton rule, it is a number ranging from 0 to 255.
11155 Default value is 110.
11158 Set the size of the output video. For the syntax of this option, check the
11159 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11161 If @option{filename} or @option{pattern} is specified, the size is set
11162 by default to the width of the specified initial state row, and the
11163 height is set to @var{width} * PHI.
11165 If @option{size} is set, it must contain the width of the specified
11166 pattern string, and the specified pattern will be centered in the
11169 If a filename or a pattern string is not specified, the size value
11170 defaults to "320x518" (used for a randomly generated initial state).
11173 If set to 1, scroll the output upward when all the rows in the output
11174 have been already filled. If set to 0, the new generated row will be
11175 written over the top row just after the bottom row is filled.
11178 @item start_full, full
11179 If set to 1, completely fill the output with generated rows before
11180 outputting the first frame.
11181 This is the default behavior, for disabling set the value to 0.
11184 If set to 1, stitch the left and right row edges together.
11185 This is the default behavior, for disabling set the value to 0.
11188 @subsection Examples
11192 Read the initial state from @file{pattern}, and specify an output of
11195 cellauto=f=pattern:s=200x400
11199 Generate a random initial row with a width of 200 cells, with a fill
11202 cellauto=ratio=2/3:s=200x200
11206 Create a pattern generated by rule 18 starting by a single alive cell
11207 centered on an initial row with width 100:
11209 cellauto=p=@@:s=100x400:full=0:rule=18
11213 Specify a more elaborated initial pattern:
11215 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
11220 @section mandelbrot
11222 Generate a Mandelbrot set fractal, and progressively zoom towards the
11223 point specified with @var{start_x} and @var{start_y}.
11225 This source accepts the following options:
11230 Set the terminal pts value. Default value is 400.
11233 Set the terminal scale value.
11234 Must be a floating point value. Default value is 0.3.
11237 Set the inner coloring mode, that is the algorithm used to draw the
11238 Mandelbrot fractal internal region.
11240 It shall assume one of the following values:
11245 Show time until convergence.
11247 Set color based on point closest to the origin of the iterations.
11252 Default value is @var{mincol}.
11255 Set the bailout value. Default value is 10.0.
11258 Set the maximum of iterations performed by the rendering
11259 algorithm. Default value is 7189.
11262 Set outer coloring mode.
11263 It shall assume one of following values:
11265 @item iteration_count
11266 Set iteration cound mode.
11267 @item normalized_iteration_count
11268 set normalized iteration count mode.
11270 Default value is @var{normalized_iteration_count}.
11273 Set frame rate, expressed as number of frames per second. Default
11277 Set frame size. For the syntax of this option, check the "Video
11278 size" section in the ffmpeg-utils manual. Default value is "640x480".
11281 Set the initial scale value. Default value is 3.0.
11284 Set the initial x position. Must be a floating point value between
11285 -100 and 100. Default value is -0.743643887037158704752191506114774.
11288 Set the initial y position. Must be a floating point value between
11289 -100 and 100. Default value is -0.131825904205311970493132056385139.
11294 Generate various test patterns, as generated by the MPlayer test filter.
11296 The size of the generated video is fixed, and is 256x256.
11297 This source is useful in particular for testing encoding features.
11299 This source accepts the following options:
11304 Specify the frame rate of the sourced video, as the number of frames
11305 generated per second. It has to be a string in the format
11306 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
11307 number or a valid video frame rate abbreviation. The default value is
11311 Set the duration of the sourced video. See
11312 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
11313 for the accepted syntax.
11315 If not specified, or the expressed duration is negative, the video is
11316 supposed to be generated forever.
11320 Set the number or the name of the test to perform. Supported tests are:
11336 Default value is "all", which will cycle through the list of all tests.
11341 mptestsrc=t=dc_luma
11344 will generate a "dc_luma" test pattern.
11346 @section frei0r_src
11348 Provide a frei0r source.
11350 To enable compilation of this filter you need to install the frei0r
11351 header and configure FFmpeg with @code{--enable-frei0r}.
11353 This source accepts the following parameters:
11358 The size of the video to generate. For the syntax of this option, check the
11359 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11362 The framerate of the generated video. It may be a string of the form
11363 @var{num}/@var{den} or a frame rate abbreviation.
11366 The name to the frei0r source to load. For more information regarding frei0r and
11367 how to set the parameters, read the @ref{frei0r} section in the video filters
11370 @item filter_params
11371 A '|'-separated list of parameters to pass to the frei0r source.
11375 For example, to generate a frei0r partik0l source with size 200x200
11376 and frame rate 10 which is overlaid on the overlay filter main input:
11378 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
11383 Generate a life pattern.
11385 This source is based on a generalization of John Conway's life game.
11387 The sourced input represents a life grid, each pixel represents a cell
11388 which can be in one of two possible states, alive or dead. Every cell
11389 interacts with its eight neighbours, which are the cells that are
11390 horizontally, vertically, or diagonally adjacent.
11392 At each interaction the grid evolves according to the adopted rule,
11393 which specifies the number of neighbor alive cells which will make a
11394 cell stay alive or born. The @option{rule} option allows one to specify
11397 This source accepts the following options:
11401 Set the file from which to read the initial grid state. In the file,
11402 each non-whitespace character is considered an alive cell, and newline
11403 is used to delimit the end of each row.
11405 If this option is not specified, the initial grid is generated
11409 Set the video rate, that is the number of frames generated per second.
11412 @item random_fill_ratio, ratio
11413 Set the random fill ratio for the initial random grid. It is a
11414 floating point number value ranging from 0 to 1, defaults to 1/PHI.
11415 It is ignored when a file is specified.
11417 @item random_seed, seed
11418 Set the seed for filling the initial random grid, must be an integer
11419 included between 0 and UINT32_MAX. If not specified, or if explicitly
11420 set to -1, the filter will try to use a good random seed on a best
11426 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
11427 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
11428 @var{NS} specifies the number of alive neighbor cells which make a
11429 live cell stay alive, and @var{NB} the number of alive neighbor cells
11430 which make a dead cell to become alive (i.e. to "born").
11431 "s" and "b" can be used in place of "S" and "B", respectively.
11433 Alternatively a rule can be specified by an 18-bits integer. The 9
11434 high order bits are used to encode the next cell state if it is alive
11435 for each number of neighbor alive cells, the low order bits specify
11436 the rule for "borning" new cells. Higher order bits encode for an
11437 higher number of neighbor cells.
11438 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
11439 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
11441 Default value is "S23/B3", which is the original Conway's game of life
11442 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
11443 cells, and will born a new cell if there are three alive cells around
11447 Set the size of the output video. For the syntax of this option, check the
11448 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11450 If @option{filename} is specified, the size is set by default to the
11451 same size of the input file. If @option{size} is set, it must contain
11452 the size specified in the input file, and the initial grid defined in
11453 that file is centered in the larger resulting area.
11455 If a filename is not specified, the size value defaults to "320x240"
11456 (used for a randomly generated initial grid).
11459 If set to 1, stitch the left and right grid edges together, and the
11460 top and bottom edges also. Defaults to 1.
11463 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
11464 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
11465 value from 0 to 255.
11468 Set the color of living (or new born) cells.
11471 Set the color of dead cells. If @option{mold} is set, this is the first color
11472 used to represent a dead cell.
11475 Set mold color, for definitely dead and moldy cells.
11477 For the syntax of these 3 color options, check the "Color" section in the
11478 ffmpeg-utils manual.
11481 @subsection Examples
11485 Read a grid from @file{pattern}, and center it on a grid of size
11488 life=f=pattern:s=300x300
11492 Generate a random grid of size 200x200, with a fill ratio of 2/3:
11494 life=ratio=2/3:s=200x200
11498 Specify a custom rule for evolving a randomly generated grid:
11504 Full example with slow death effect (mold) using @command{ffplay}:
11506 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
11512 @anchor{haldclutsrc}
11514 @anchor{rgbtestsrc}
11516 @anchor{smptehdbars}
11518 @section allyuv, color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
11520 The @code{allyuv} source returns frames of size 4096x4096 of all yuv colors.
11522 The @code{color} source provides an uniformly colored input.
11524 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
11525 @ref{haldclut} filter.
11527 The @code{nullsrc} source returns unprocessed video frames. It is
11528 mainly useful to be employed in analysis / debugging tools, or as the
11529 source for filters which ignore the input data.
11531 The @code{rgbtestsrc} source generates an RGB test pattern useful for
11532 detecting RGB vs BGR issues. You should see a red, green and blue
11533 stripe from top to bottom.
11535 The @code{smptebars} source generates a color bars pattern, based on
11536 the SMPTE Engineering Guideline EG 1-1990.
11538 The @code{smptehdbars} source generates a color bars pattern, based on
11539 the SMPTE RP 219-2002.
11541 The @code{testsrc} source generates a test video pattern, showing a
11542 color pattern, a scrolling gradient and a timestamp. This is mainly
11543 intended for testing purposes.
11545 The sources accept the following parameters:
11550 Specify the color of the source, only available in the @code{color}
11551 source. For the syntax of this option, check the "Color" section in the
11552 ffmpeg-utils manual.
11555 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
11556 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
11557 pixels to be used as identity matrix for 3D lookup tables. Each component is
11558 coded on a @code{1/(N*N)} scale.
11561 Specify the size of the sourced video. For the syntax of this option, check the
11562 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11563 The default value is @code{320x240}.
11565 This option is not available with the @code{haldclutsrc} filter.
11568 Specify the frame rate of the sourced video, as the number of frames
11569 generated per second. It has to be a string in the format
11570 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
11571 number or a valid video frame rate abbreviation. The default value is
11575 Set the sample aspect ratio of the sourced video.
11578 Set the duration of the sourced video. See
11579 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
11580 for the accepted syntax.
11582 If not specified, or the expressed duration is negative, the video is
11583 supposed to be generated forever.
11586 Set the number of decimals to show in the timestamp, only available in the
11587 @code{testsrc} source.
11589 The displayed timestamp value will correspond to the original
11590 timestamp value multiplied by the power of 10 of the specified
11591 value. Default value is 0.
11594 For example the following:
11596 testsrc=duration=5.3:size=qcif:rate=10
11599 will generate a video with a duration of 5.3 seconds, with size
11600 176x144 and a frame rate of 10 frames per second.
11602 The following graph description will generate a red source
11603 with an opacity of 0.2, with size "qcif" and a frame rate of 10
11606 color=c=red@@0.2:s=qcif:r=10
11609 If the input content is to be ignored, @code{nullsrc} can be used. The
11610 following command generates noise in the luminance plane by employing
11611 the @code{geq} filter:
11613 nullsrc=s=256x256, geq=random(1)*255:128:128
11616 @subsection Commands
11618 The @code{color} source supports the following commands:
11622 Set the color of the created image. Accepts the same syntax of the
11623 corresponding @option{color} option.
11626 @c man end VIDEO SOURCES
11628 @chapter Video Sinks
11629 @c man begin VIDEO SINKS
11631 Below is a description of the currently available video sinks.
11633 @section buffersink
11635 Buffer video frames, and make them available to the end of the filter
11638 This sink is mainly intended for programmatic use, in particular
11639 through the interface defined in @file{libavfilter/buffersink.h}
11640 or the options system.
11642 It accepts a pointer to an AVBufferSinkContext structure, which
11643 defines the incoming buffers' formats, to be passed as the opaque
11644 parameter to @code{avfilter_init_filter} for initialization.
11648 Null video sink: do absolutely nothing with the input video. It is
11649 mainly useful as a template and for use in analysis / debugging
11652 @c man end VIDEO SINKS
11654 @chapter Multimedia Filters
11655 @c man begin MULTIMEDIA FILTERS
11657 Below is a description of the currently available multimedia filters.
11659 @section avectorscope
11661 Convert input audio to a video output, representing the audio vector
11664 The filter is used to measure the difference between channels of stereo
11665 audio stream. A monoaural signal, consisting of identical left and right
11666 signal, results in straight vertical line. Any stereo separation is visible
11667 as a deviation from this line, creating a Lissajous figure.
11668 If the straight (or deviation from it) but horizontal line appears this
11669 indicates that the left and right channels are out of phase.
11671 The filter accepts the following options:
11675 Set the vectorscope mode.
11677 Available values are:
11680 Lissajous rotated by 45 degrees.
11683 Same as above but not rotated.
11686 Default value is @samp{lissajous}.
11689 Set the video size for the output. For the syntax of this option, check the
11690 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11691 Default value is @code{400x400}.
11694 Set the output frame rate. Default value is @code{25}.
11700 Specify the red, green, blue and alpha contrast. Default values are @code{40},
11701 @code{160}, @code{80} and @code{255}.
11702 Allowed range is @code{[0, 255]}.
11708 Specify the red, green, blue and alpha fade. Default values are @code{15},
11709 @code{10}, @code{5} and @code{5}.
11710 Allowed range is @code{[0, 255]}.
11713 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
11716 @subsection Examples
11720 Complete example using @command{ffplay}:
11722 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
11723 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
11729 Concatenate audio and video streams, joining them together one after the
11732 The filter works on segments of synchronized video and audio streams. All
11733 segments must have the same number of streams of each type, and that will
11734 also be the number of streams at output.
11736 The filter accepts the following options:
11741 Set the number of segments. Default is 2.
11744 Set the number of output video streams, that is also the number of video
11745 streams in each segment. Default is 1.
11748 Set the number of output audio streams, that is also the number of audio
11749 streams in each segment. Default is 0.
11752 Activate unsafe mode: do not fail if segments have a different format.
11756 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
11757 @var{a} audio outputs.
11759 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
11760 segment, in the same order as the outputs, then the inputs for the second
11763 Related streams do not always have exactly the same duration, for various
11764 reasons including codec frame size or sloppy authoring. For that reason,
11765 related synchronized streams (e.g. a video and its audio track) should be
11766 concatenated at once. The concat filter will use the duration of the longest
11767 stream in each segment (except the last one), and if necessary pad shorter
11768 audio streams with silence.
11770 For this filter to work correctly, all segments must start at timestamp 0.
11772 All corresponding streams must have the same parameters in all segments; the
11773 filtering system will automatically select a common pixel format for video
11774 streams, and a common sample format, sample rate and channel layout for
11775 audio streams, but other settings, such as resolution, must be converted
11776 explicitly by the user.
11778 Different frame rates are acceptable but will result in variable frame rate
11779 at output; be sure to configure the output file to handle it.
11781 @subsection Examples
11785 Concatenate an opening, an episode and an ending, all in bilingual version
11786 (video in stream 0, audio in streams 1 and 2):
11788 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
11789 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
11790 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
11791 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
11795 Concatenate two parts, handling audio and video separately, using the
11796 (a)movie sources, and adjusting the resolution:
11798 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
11799 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
11800 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
11802 Note that a desync will happen at the stitch if the audio and video streams
11803 do not have exactly the same duration in the first file.
11810 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
11811 it unchanged. By default, it logs a message at a frequency of 10Hz with the
11812 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
11813 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
11815 The filter also has a video output (see the @var{video} option) with a real
11816 time graph to observe the loudness evolution. The graphic contains the logged
11817 message mentioned above, so it is not printed anymore when this option is set,
11818 unless the verbose logging is set. The main graphing area contains the
11819 short-term loudness (3 seconds of analysis), and the gauge on the right is for
11820 the momentary loudness (400 milliseconds).
11822 More information about the Loudness Recommendation EBU R128 on
11823 @url{http://tech.ebu.ch/loudness}.
11825 The filter accepts the following options:
11830 Activate the video output. The audio stream is passed unchanged whether this
11831 option is set or no. The video stream will be the first output stream if
11832 activated. Default is @code{0}.
11835 Set the video size. This option is for video only. For the syntax of this
11837 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11838 Default and minimum resolution is @code{640x480}.
11841 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
11842 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
11843 other integer value between this range is allowed.
11846 Set metadata injection. If set to @code{1}, the audio input will be segmented
11847 into 100ms output frames, each of them containing various loudness information
11848 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
11850 Default is @code{0}.
11853 Force the frame logging level.
11855 Available values are:
11858 information logging level
11860 verbose logging level
11863 By default, the logging level is set to @var{info}. If the @option{video} or
11864 the @option{metadata} options are set, it switches to @var{verbose}.
11869 Available modes can be cumulated (the option is a @code{flag} type). Possible
11873 Disable any peak mode (default).
11875 Enable sample-peak mode.
11877 Simple peak mode looking for the higher sample value. It logs a message
11878 for sample-peak (identified by @code{SPK}).
11880 Enable true-peak mode.
11882 If enabled, the peak lookup is done on an over-sampled version of the input
11883 stream for better peak accuracy. It logs a message for true-peak.
11884 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
11885 This mode requires a build with @code{libswresample}.
11890 @subsection Examples
11894 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
11896 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
11900 Run an analysis with @command{ffmpeg}:
11902 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
11906 @section interleave, ainterleave
11908 Temporally interleave frames from several inputs.
11910 @code{interleave} works with video inputs, @code{ainterleave} with audio.
11912 These filters read frames from several inputs and send the oldest
11913 queued frame to the output.
11915 Input streams must have a well defined, monotonically increasing frame
11918 In order to submit one frame to output, these filters need to enqueue
11919 at least one frame for each input, so they cannot work in case one
11920 input is not yet terminated and will not receive incoming frames.
11922 For example consider the case when one input is a @code{select} filter
11923 which always drop input frames. The @code{interleave} filter will keep
11924 reading from that input, but it will never be able to send new frames
11925 to output until the input will send an end-of-stream signal.
11927 Also, depending on inputs synchronization, the filters will drop
11928 frames in case one input receives more frames than the other ones, and
11929 the queue is already filled.
11931 These filters accept the following options:
11935 Set the number of different inputs, it is 2 by default.
11938 @subsection Examples
11942 Interleave frames belonging to different streams using @command{ffmpeg}:
11944 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
11948 Add flickering blur effect:
11950 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
11954 @section perms, aperms
11956 Set read/write permissions for the output frames.
11958 These filters are mainly aimed at developers to test direct path in the
11959 following filter in the filtergraph.
11961 The filters accept the following options:
11965 Select the permissions mode.
11967 It accepts the following values:
11970 Do nothing. This is the default.
11972 Set all the output frames read-only.
11974 Set all the output frames directly writable.
11976 Make the frame read-only if writable, and writable if read-only.
11978 Set each output frame read-only or writable randomly.
11982 Set the seed for the @var{random} mode, must be an integer included between
11983 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
11984 @code{-1}, the filter will try to use a good random seed on a best effort
11988 Note: in case of auto-inserted filter between the permission filter and the
11989 following one, the permission might not be received as expected in that
11990 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
11991 perms/aperms filter can avoid this problem.
11993 @section select, aselect
11995 Select frames to pass in output.
11997 This filter accepts the following options:
12002 Set expression, which is evaluated for each input frame.
12004 If the expression is evaluated to zero, the frame is discarded.
12006 If the evaluation result is negative or NaN, the frame is sent to the
12007 first output; otherwise it is sent to the output with index
12008 @code{ceil(val)-1}, assuming that the input index starts from 0.
12010 For example a value of @code{1.2} corresponds to the output with index
12011 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
12014 Set the number of outputs. The output to which to send the selected
12015 frame is based on the result of the evaluation. Default value is 1.
12018 The expression can contain the following constants:
12022 The (sequential) number of the filtered frame, starting from 0.
12025 The (sequential) number of the selected frame, starting from 0.
12027 @item prev_selected_n
12028 The sequential number of the last selected frame. It's NAN if undefined.
12031 The timebase of the input timestamps.
12034 The PTS (Presentation TimeStamp) of the filtered video frame,
12035 expressed in @var{TB} units. It's NAN if undefined.
12038 The PTS of the filtered video frame,
12039 expressed in seconds. It's NAN if undefined.
12042 The PTS of the previously filtered video frame. It's NAN if undefined.
12044 @item prev_selected_pts
12045 The PTS of the last previously filtered video frame. It's NAN if undefined.
12047 @item prev_selected_t
12048 The PTS of the last previously selected video frame. It's NAN if undefined.
12051 The PTS of the first video frame in the video. It's NAN if undefined.
12054 The time of the first video frame in the video. It's NAN if undefined.
12056 @item pict_type @emph{(video only)}
12057 The type of the filtered frame. It can assume one of the following
12069 @item interlace_type @emph{(video only)}
12070 The frame interlace type. It can assume one of the following values:
12073 The frame is progressive (not interlaced).
12075 The frame is top-field-first.
12077 The frame is bottom-field-first.
12080 @item consumed_sample_n @emph{(audio only)}
12081 the number of selected samples before the current frame
12083 @item samples_n @emph{(audio only)}
12084 the number of samples in the current frame
12086 @item sample_rate @emph{(audio only)}
12087 the input sample rate
12090 This is 1 if the filtered frame is a key-frame, 0 otherwise.
12093 the position in the file of the filtered frame, -1 if the information
12094 is not available (e.g. for synthetic video)
12096 @item scene @emph{(video only)}
12097 value between 0 and 1 to indicate a new scene; a low value reflects a low
12098 probability for the current frame to introduce a new scene, while a higher
12099 value means the current frame is more likely to be one (see the example below)
12103 The default value of the select expression is "1".
12105 @subsection Examples
12109 Select all frames in input:
12114 The example above is the same as:
12126 Select only I-frames:
12128 select='eq(pict_type\,I)'
12132 Select one frame every 100:
12134 select='not(mod(n\,100))'
12138 Select only frames contained in the 10-20 time interval:
12140 select=between(t\,10\,20)
12144 Select only I frames contained in the 10-20 time interval:
12146 select=between(t\,10\,20)*eq(pict_type\,I)
12150 Select frames with a minimum distance of 10 seconds:
12152 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
12156 Use aselect to select only audio frames with samples number > 100:
12158 aselect='gt(samples_n\,100)'
12162 Create a mosaic of the first scenes:
12164 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
12167 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
12171 Send even and odd frames to separate outputs, and compose them:
12173 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
12177 @section sendcmd, asendcmd
12179 Send commands to filters in the filtergraph.
12181 These filters read commands to be sent to other filters in the
12184 @code{sendcmd} must be inserted between two video filters,
12185 @code{asendcmd} must be inserted between two audio filters, but apart
12186 from that they act the same way.
12188 The specification of commands can be provided in the filter arguments
12189 with the @var{commands} option, or in a file specified by the
12190 @var{filename} option.
12192 These filters accept the following options:
12195 Set the commands to be read and sent to the other filters.
12197 Set the filename of the commands to be read and sent to the other
12201 @subsection Commands syntax
12203 A commands description consists of a sequence of interval
12204 specifications, comprising a list of commands to be executed when a
12205 particular event related to that interval occurs. The occurring event
12206 is typically the current frame time entering or leaving a given time
12209 An interval is specified by the following syntax:
12211 @var{START}[-@var{END}] @var{COMMANDS};
12214 The time interval is specified by the @var{START} and @var{END} times.
12215 @var{END} is optional and defaults to the maximum time.
12217 The current frame time is considered within the specified interval if
12218 it is included in the interval [@var{START}, @var{END}), that is when
12219 the time is greater or equal to @var{START} and is lesser than
12222 @var{COMMANDS} consists of a sequence of one or more command
12223 specifications, separated by ",", relating to that interval. The
12224 syntax of a command specification is given by:
12226 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
12229 @var{FLAGS} is optional and specifies the type of events relating to
12230 the time interval which enable sending the specified command, and must
12231 be a non-null sequence of identifier flags separated by "+" or "|" and
12232 enclosed between "[" and "]".
12234 The following flags are recognized:
12237 The command is sent when the current frame timestamp enters the
12238 specified interval. In other words, the command is sent when the
12239 previous frame timestamp was not in the given interval, and the
12243 The command is sent when the current frame timestamp leaves the
12244 specified interval. In other words, the command is sent when the
12245 previous frame timestamp was in the given interval, and the
12249 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
12252 @var{TARGET} specifies the target of the command, usually the name of
12253 the filter class or a specific filter instance name.
12255 @var{COMMAND} specifies the name of the command for the target filter.
12257 @var{ARG} is optional and specifies the optional list of argument for
12258 the given @var{COMMAND}.
12260 Between one interval specification and another, whitespaces, or
12261 sequences of characters starting with @code{#} until the end of line,
12262 are ignored and can be used to annotate comments.
12264 A simplified BNF description of the commands specification syntax
12267 @var{COMMAND_FLAG} ::= "enter" | "leave"
12268 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
12269 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
12270 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
12271 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
12272 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
12275 @subsection Examples
12279 Specify audio tempo change at second 4:
12281 asendcmd=c='4.0 atempo tempo 1.5',atempo
12285 Specify a list of drawtext and hue commands in a file.
12287 # show text in the interval 5-10
12288 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
12289 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
12291 # desaturate the image in the interval 15-20
12292 15.0-20.0 [enter] hue s 0,
12293 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
12295 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
12297 # apply an exponential saturation fade-out effect, starting from time 25
12298 25 [enter] hue s exp(25-t)
12301 A filtergraph allowing to read and process the above command list
12302 stored in a file @file{test.cmd}, can be specified with:
12304 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
12309 @section setpts, asetpts
12311 Change the PTS (presentation timestamp) of the input frames.
12313 @code{setpts} works on video frames, @code{asetpts} on audio frames.
12315 This filter accepts the following options:
12320 The expression which is evaluated for each frame to construct its timestamp.
12324 The expression is evaluated through the eval API and can contain the following
12329 frame rate, only defined for constant frame-rate video
12332 The presentation timestamp in input
12335 The count of the input frame for video or the number of consumed samples,
12336 not including the current frame for audio, starting from 0.
12338 @item NB_CONSUMED_SAMPLES
12339 The number of consumed samples, not including the current frame (only
12342 @item NB_SAMPLES, S
12343 The number of samples in the current frame (only audio)
12345 @item SAMPLE_RATE, SR
12346 The audio sample rate.
12349 The PTS of the first frame.
12352 the time in seconds of the first frame
12355 State whether the current frame is interlaced.
12358 the time in seconds of the current frame
12361 original position in the file of the frame, or undefined if undefined
12362 for the current frame
12365 The previous input PTS.
12368 previous input time in seconds
12371 The previous output PTS.
12374 previous output time in seconds
12377 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
12381 The wallclock (RTC) time at the start of the movie in microseconds.
12384 The timebase of the input timestamps.
12388 @subsection Examples
12392 Start counting PTS from zero
12394 setpts=PTS-STARTPTS
12398 Apply fast motion effect:
12404 Apply slow motion effect:
12410 Set fixed rate of 25 frames per second:
12416 Set fixed rate 25 fps with some jitter:
12418 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
12422 Apply an offset of 10 seconds to the input PTS:
12428 Generate timestamps from a "live source" and rebase onto the current timebase:
12430 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
12434 Generate timestamps by counting samples:
12441 @section settb, asettb
12443 Set the timebase to use for the output frames timestamps.
12444 It is mainly useful for testing timebase configuration.
12446 It accepts the following parameters:
12451 The expression which is evaluated into the output timebase.
12455 The value for @option{tb} is an arithmetic expression representing a
12456 rational. The expression can contain the constants "AVTB" (the default
12457 timebase), "intb" (the input timebase) and "sr" (the sample rate,
12458 audio only). Default value is "intb".
12460 @subsection Examples
12464 Set the timebase to 1/25:
12470 Set the timebase to 1/10:
12476 Set the timebase to 1001/1000:
12482 Set the timebase to 2*intb:
12488 Set the default timebase value:
12495 Convert input audio to a video output representing
12496 frequency spectrum logarithmically (using constant Q transform with
12497 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
12499 The filter accepts the following options:
12503 Specify transform volume (multiplier) expression. The expression can contain
12506 @item frequency, freq, f
12507 the frequency where transform is evaluated
12508 @item timeclamp, tc
12509 value of timeclamp option
12513 @item a_weighting(f)
12514 A-weighting of equal loudness
12515 @item b_weighting(f)
12516 B-weighting of equal loudness
12517 @item c_weighting(f)
12518 C-weighting of equal loudness
12520 Default value is @code{16}.
12523 Specify transform length expression. The expression can contain variables:
12525 @item frequency, freq, f
12526 the frequency where transform is evaluated
12527 @item timeclamp, tc
12528 value of timeclamp option
12530 Default value is @code{384/f*tc/(384/f+tc)}.
12533 Specify the transform timeclamp. At low frequency, there is trade-off between
12534 accuracy in time domain and frequency domain. If timeclamp is lower,
12535 event in time domain is represented more accurately (such as fast bass drum),
12536 otherwise event in frequency domain is represented more accurately
12537 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
12540 Specify the transform coeffclamp. If coeffclamp is lower, transform is
12541 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
12542 Default value is @code{1.0}.
12545 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
12546 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
12547 Default value is @code{3.0}.
12550 Specify gamma of bargraph. Acceptable value is [1.0, 7.0].
12551 Default value is @code{1.0}.
12554 Specify font file for use with freetype. If not specified, use embedded font.
12557 Specify font color expression. This is arithmetic expression that should return
12558 integer value 0xRRGGBB. The expression can contain variables:
12560 @item frequency, freq, f
12561 the frequency where transform is evaluated
12562 @item timeclamp, tc
12563 value of timeclamp option
12568 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
12569 @item r(x), g(x), b(x)
12570 red, green, and blue value of intensity x
12572 Default value is @code{st(0, (midi(f)-59.5)/12);
12573 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
12574 r(1-ld(1)) + b(ld(1))}
12577 If set to 1 (the default), the video size is 1920x1080 (full HD),
12578 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
12581 Specify video fps. Default value is @code{25}.
12584 Specify number of transform per frame, so there are fps*count transforms
12585 per second. Note that audio data rate must be divisible by fps*count.
12586 Default value is @code{6}.
12590 @subsection Examples
12594 Playing audio while showing the spectrum:
12596 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
12600 Same as above, but with frame rate 30 fps:
12602 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
12606 Playing at 960x540 and lower CPU usage:
12608 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
12612 A1 and its harmonics: A1, A2, (near)E3, A3:
12614 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),
12615 asplit[a][out1]; [a] showcqt [out0]'
12619 Same as above, but with more accuracy in frequency domain (and slower):
12621 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),
12622 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
12626 B-weighting of equal loudness
12628 volume=16*b_weighting(f)
12634 tlength=100/f*tc/(100/f+tc)
12638 Custom fontcolor, C-note is colored green, others are colored blue
12640 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))'
12644 Custom gamma, now spectrum is linear to the amplitude.
12651 @section showspectrum
12653 Convert input audio to a video output, representing the audio frequency
12656 The filter accepts the following options:
12660 Specify the video size for the output. For the syntax of this option, check the
12661 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12662 Default value is @code{640x512}.
12665 Specify how the spectrum should slide along the window.
12667 It accepts the following values:
12670 the samples start again on the left when they reach the right
12672 the samples scroll from right to left
12674 frames are only produced when the samples reach the right
12677 Default value is @code{replace}.
12680 Specify display mode.
12682 It accepts the following values:
12685 all channels are displayed in the same row
12687 all channels are displayed in separate rows
12690 Default value is @samp{combined}.
12693 Specify display color mode.
12695 It accepts the following values:
12698 each channel is displayed in a separate color
12700 each channel is is displayed using the same color scheme
12703 Default value is @samp{channel}.
12706 Specify scale used for calculating intensity color values.
12708 It accepts the following values:
12713 square root, default
12720 Default value is @samp{sqrt}.
12723 Set saturation modifier for displayed colors. Negative values provide
12724 alternative color scheme. @code{0} is no saturation at all.
12725 Saturation must be in [-10.0, 10.0] range.
12726 Default value is @code{1}.
12729 Set window function.
12731 It accepts the following values:
12734 No samples pre-processing (do not expect this to be faster)
12743 Default value is @code{hann}.
12746 The usage is very similar to the showwaves filter; see the examples in that
12749 @subsection Examples
12753 Large window with logarithmic color scaling:
12755 showspectrum=s=1280x480:scale=log
12759 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
12761 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
12762 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
12766 @section showvolume
12768 Convert input audio volume to a video output.
12770 The filter accepts the following options:
12777 Set border width, allowed range is [0, 5]. Default is 1.
12780 Set channel width, allowed range is [40, 1080]. Default is 400.
12783 Set channel height, allowed range is [1, 100]. Default is 20.
12786 Set fade, allowed range is [1, 255]. Default is 20.
12789 Set volume color expression.
12791 The expression can use the following variables:
12795 Current max volume of channel in dB.
12798 Current channel number, starting from 0.
12802 If set, displays channel names. Default is enabled.
12807 Convert input audio to a video output, representing the samples waves.
12809 The filter accepts the following options:
12813 Specify the video size for the output. For the syntax of this option, check the
12814 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12815 Default value is @code{600x240}.
12820 Available values are:
12823 Draw a point for each sample.
12826 Draw a vertical line for each sample.
12829 Draw a point for each sample and a line between them.
12832 Draw a centered vertical line for each sample.
12835 Default value is @code{point}.
12838 Set the number of samples which are printed on the same column. A
12839 larger value will decrease the frame rate. Must be a positive
12840 integer. This option can be set only if the value for @var{rate}
12841 is not explicitly specified.
12844 Set the (approximate) output frame rate. This is done by setting the
12845 option @var{n}. Default value is "25".
12847 @item split_channels
12848 Set if channels should be drawn separately or overlap. Default value is 0.
12852 @subsection Examples
12856 Output the input file audio and the corresponding video representation
12859 amovie=a.mp3,asplit[out0],showwaves[out1]
12863 Create a synthetic signal and show it with showwaves, forcing a
12864 frame rate of 30 frames per second:
12866 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
12870 @section showwavespic
12872 Convert input audio to a single video frame, representing the samples waves.
12874 The filter accepts the following options:
12878 Specify the video size for the output. For the syntax of this option, check the
12879 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12880 Default value is @code{600x240}.
12882 @item split_channels
12883 Set if channels should be drawn separately or overlap. Default value is 0.
12886 @subsection Examples
12890 Extract a channel split representation of the wave form of a whole audio track
12891 in a 1024x800 picture using @command{ffmpeg}:
12893 ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png
12897 @section split, asplit
12899 Split input into several identical outputs.
12901 @code{asplit} works with audio input, @code{split} with video.
12903 The filter accepts a single parameter which specifies the number of outputs. If
12904 unspecified, it defaults to 2.
12906 @subsection Examples
12910 Create two separate outputs from the same input:
12912 [in] split [out0][out1]
12916 To create 3 or more outputs, you need to specify the number of
12919 [in] asplit=3 [out0][out1][out2]
12923 Create two separate outputs from the same input, one cropped and
12926 [in] split [splitout1][splitout2];
12927 [splitout1] crop=100:100:0:0 [cropout];
12928 [splitout2] pad=200:200:100:100 [padout];
12932 Create 5 copies of the input audio with @command{ffmpeg}:
12934 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
12940 Receive commands sent through a libzmq client, and forward them to
12941 filters in the filtergraph.
12943 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
12944 must be inserted between two video filters, @code{azmq} between two
12947 To enable these filters you need to install the libzmq library and
12948 headers and configure FFmpeg with @code{--enable-libzmq}.
12950 For more information about libzmq see:
12951 @url{http://www.zeromq.org/}
12953 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
12954 receives messages sent through a network interface defined by the
12955 @option{bind_address} option.
12957 The received message must be in the form:
12959 @var{TARGET} @var{COMMAND} [@var{ARG}]
12962 @var{TARGET} specifies the target of the command, usually the name of
12963 the filter class or a specific filter instance name.
12965 @var{COMMAND} specifies the name of the command for the target filter.
12967 @var{ARG} is optional and specifies the optional argument list for the
12968 given @var{COMMAND}.
12970 Upon reception, the message is processed and the corresponding command
12971 is injected into the filtergraph. Depending on the result, the filter
12972 will send a reply to the client, adopting the format:
12974 @var{ERROR_CODE} @var{ERROR_REASON}
12978 @var{MESSAGE} is optional.
12980 @subsection Examples
12982 Look at @file{tools/zmqsend} for an example of a zmq client which can
12983 be used to send commands processed by these filters.
12985 Consider the following filtergraph generated by @command{ffplay}
12987 ffplay -dumpgraph 1 -f lavfi "
12988 color=s=100x100:c=red [l];
12989 color=s=100x100:c=blue [r];
12990 nullsrc=s=200x100, zmq [bg];
12991 [bg][l] overlay [bg+l];
12992 [bg+l][r] overlay=x=100 "
12995 To change the color of the left side of the video, the following
12996 command can be used:
12998 echo Parsed_color_0 c yellow | tools/zmqsend
13001 To change the right side:
13003 echo Parsed_color_1 c pink | tools/zmqsend
13006 @c man end MULTIMEDIA FILTERS
13008 @chapter Multimedia Sources
13009 @c man begin MULTIMEDIA SOURCES
13011 Below is a description of the currently available multimedia sources.
13015 This is the same as @ref{movie} source, except it selects an audio
13021 Read audio and/or video stream(s) from a movie container.
13023 It accepts the following parameters:
13027 The name of the resource to read (not necessarily a file; it can also be a
13028 device or a stream accessed through some protocol).
13030 @item format_name, f
13031 Specifies the format assumed for the movie to read, and can be either
13032 the name of a container or an input device. If not specified, the
13033 format is guessed from @var{movie_name} or by probing.
13035 @item seek_point, sp
13036 Specifies the seek point in seconds. The frames will be output
13037 starting from this seek point. The parameter is evaluated with
13038 @code{av_strtod}, so the numerical value may be suffixed by an IS
13039 postfix. The default value is "0".
13042 Specifies the streams to read. Several streams can be specified,
13043 separated by "+". The source will then have as many outputs, in the
13044 same order. The syntax is explained in the ``Stream specifiers''
13045 section in the ffmpeg manual. Two special names, "dv" and "da" specify
13046 respectively the default (best suited) video and audio stream. Default
13047 is "dv", or "da" if the filter is called as "amovie".
13049 @item stream_index, si
13050 Specifies the index of the video stream to read. If the value is -1,
13051 the most suitable video stream will be automatically selected. The default
13052 value is "-1". Deprecated. If the filter is called "amovie", it will select
13053 audio instead of video.
13056 Specifies how many times to read the stream in sequence.
13057 If the value is less than 1, the stream will be read again and again.
13058 Default value is "1".
13060 Note that when the movie is looped the source timestamps are not
13061 changed, so it will generate non monotonically increasing timestamps.
13064 It allows overlaying a second video on top of the main input of
13065 a filtergraph, as shown in this graph:
13067 input -----------> deltapts0 --> overlay --> output
13070 movie --> scale--> deltapts1 -------+
13072 @subsection Examples
13076 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
13077 on top of the input labelled "in":
13079 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
13080 [in] setpts=PTS-STARTPTS [main];
13081 [main][over] overlay=16:16 [out]
13085 Read from a video4linux2 device, and overlay it on top of the input
13088 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
13089 [in] setpts=PTS-STARTPTS [main];
13090 [main][over] overlay=16:16 [out]
13094 Read the first video stream and the audio stream with id 0x81 from
13095 dvd.vob; the video is connected to the pad named "video" and the audio is
13096 connected to the pad named "audio":
13098 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
13102 @c man end MULTIMEDIA SOURCES