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
1820 @section extrastereo
1822 Linearly increases the difference between left and right channels which
1823 adds some sort of "live" effect to playback.
1825 The filter accepts the following option:
1829 Sets the difference coefficient (default: 2.5). 0.0 means mono sound
1830 (average of both channels), with 1.0 sound will be unchanged, with
1831 -1.0 left and right channels will be swapped.
1834 Enable clipping. By default is enabled.
1838 Apply a flanging effect to the audio.
1840 The filter accepts the following options:
1844 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
1847 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
1850 Set percentage regeneration (delayed signal feedback). Range from -95 to 95.
1854 Set percentage of delayed signal mixed with original. Range from 0 to 100.
1855 Default value is 71.
1858 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
1861 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
1862 Default value is @var{sinusoidal}.
1865 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
1866 Default value is 25.
1869 Set delay-line interpolation, @var{linear} or @var{quadratic}.
1870 Default is @var{linear}.
1875 Apply a high-pass filter with 3dB point frequency.
1876 The filter can be either single-pole, or double-pole (the default).
1877 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1879 The filter accepts the following options:
1883 Set frequency in Hz. Default is 3000.
1886 Set number of poles. Default is 2.
1889 Set method to specify band-width of filter.
1902 Specify the band-width of a filter in width_type units.
1903 Applies only to double-pole filter.
1904 The default is 0.707q and gives a Butterworth response.
1909 Join multiple input streams into one multi-channel stream.
1911 It accepts the following parameters:
1915 The number of input streams. It defaults to 2.
1917 @item channel_layout
1918 The desired output channel layout. It defaults to stereo.
1921 Map channels from inputs to output. The argument is a '|'-separated list of
1922 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1923 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1924 can be either the name of the input channel (e.g. FL for front left) or its
1925 index in the specified input stream. @var{out_channel} is the name of the output
1929 The filter will attempt to guess the mappings when they are not specified
1930 explicitly. It does so by first trying to find an unused matching input channel
1931 and if that fails it picks the first unused input channel.
1933 Join 3 inputs (with properly set channel layouts):
1935 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1938 Build a 5.1 output from 6 single-channel streams:
1940 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1941 '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'
1947 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1949 To enable compilation of this filter you need to configure FFmpeg with
1950 @code{--enable-ladspa}.
1954 Specifies the name of LADSPA plugin library to load. If the environment
1955 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1956 each one of the directories specified by the colon separated list in
1957 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1958 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1959 @file{/usr/lib/ladspa/}.
1962 Specifies the plugin within the library. Some libraries contain only
1963 one plugin, but others contain many of them. If this is not set filter
1964 will list all available plugins within the specified library.
1967 Set the '|' separated list of controls which are zero or more floating point
1968 values that determine the behavior of the loaded plugin (for example delay,
1970 Controls need to be defined using the following syntax:
1971 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1972 @var{valuei} is the value set on the @var{i}-th control.
1973 If @option{controls} is set to @code{help}, all available controls and
1974 their valid ranges are printed.
1976 @item sample_rate, s
1977 Specify the sample rate, default to 44100. Only used if plugin have
1981 Set the number of samples per channel per each output frame, default
1982 is 1024. Only used if plugin have zero inputs.
1985 Set the minimum duration of the sourced audio. See
1986 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
1987 for the accepted syntax.
1988 Note that the resulting duration may be greater than the specified duration,
1989 as the generated audio is always cut at the end of a complete frame.
1990 If not specified, or the expressed duration is negative, the audio is
1991 supposed to be generated forever.
1992 Only used if plugin have zero inputs.
1996 @subsection Examples
2000 List all available plugins within amp (LADSPA example plugin) library:
2006 List all available controls and their valid ranges for @code{vcf_notch}
2007 plugin from @code{VCF} library:
2009 ladspa=f=vcf:p=vcf_notch:c=help
2013 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
2016 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
2020 Add reverberation to the audio using TAP-plugins
2021 (Tom's Audio Processing plugins):
2023 ladspa=file=tap_reverb:tap_reverb
2027 Generate white noise, with 0.2 amplitude:
2029 ladspa=file=cmt:noise_source_white:c=c0=.2
2033 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
2034 @code{C* Audio Plugin Suite} (CAPS) library:
2036 ladspa=file=caps:Click:c=c1=20'
2040 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
2042 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
2046 @subsection Commands
2048 This filter supports the following commands:
2051 Modify the @var{N}-th control value.
2053 If the specified value is not valid, it is ignored and prior one is kept.
2058 Apply a low-pass filter with 3dB point frequency.
2059 The filter can be either single-pole or double-pole (the default).
2060 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
2062 The filter accepts the following options:
2066 Set frequency in Hz. Default is 500.
2069 Set number of poles. Default is 2.
2072 Set method to specify band-width of filter.
2085 Specify the band-width of a filter in width_type units.
2086 Applies only to double-pole filter.
2087 The default is 0.707q and gives a Butterworth response.
2093 Mix channels with specific gain levels. The filter accepts the output
2094 channel layout followed by a set of channels definitions.
2096 This filter is also designed to efficiently remap the channels of an audio
2099 The filter accepts parameters of the form:
2100 "@var{l}|@var{outdef}|@var{outdef}|..."
2104 output channel layout or number of channels
2107 output channel specification, of the form:
2108 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
2111 output channel to define, either a channel name (FL, FR, etc.) or a channel
2112 number (c0, c1, etc.)
2115 multiplicative coefficient for the channel, 1 leaving the volume unchanged
2118 input channel to use, see out_name for details; it is not possible to mix
2119 named and numbered input channels
2122 If the `=' in a channel specification is replaced by `<', then the gains for
2123 that specification will be renormalized so that the total is 1, thus
2124 avoiding clipping noise.
2126 @subsection Mixing examples
2128 For example, if you want to down-mix from stereo to mono, but with a bigger
2129 factor for the left channel:
2131 pan=1c|c0=0.9*c0+0.1*c1
2134 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
2135 7-channels surround:
2137 pan=stereo| FL < FL + 0.5*FC + 0.6*BL + 0.6*SL | FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
2140 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
2141 that should be preferred (see "-ac" option) unless you have very specific
2144 @subsection Remapping examples
2146 The channel remapping will be effective if, and only if:
2149 @item gain coefficients are zeroes or ones,
2150 @item only one input per channel output,
2153 If all these conditions are satisfied, the filter will notify the user ("Pure
2154 channel mapping detected"), and use an optimized and lossless method to do the
2157 For example, if you have a 5.1 source and want a stereo audio stream by
2158 dropping the extra channels:
2160 pan="stereo| c0=FL | c1=FR"
2163 Given the same source, you can also switch front left and front right channels
2164 and keep the input channel layout:
2166 pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"
2169 If the input is a stereo audio stream, you can mute the front left channel (and
2170 still keep the stereo channel layout) with:
2175 Still with a stereo audio stream input, you can copy the right channel in both
2176 front left and right:
2178 pan="stereo| c0=FR | c1=FR"
2183 ReplayGain scanner filter. This filter takes an audio stream as an input and
2184 outputs it unchanged.
2185 At end of filtering it displays @code{track_gain} and @code{track_peak}.
2189 Convert the audio sample format, sample rate and channel layout. It is
2190 not meant to be used directly.
2192 @section sidechaincompress
2194 This filter acts like normal compressor but has the ability to compress
2195 detected signal using second input signal.
2196 It needs two input streams and returns one output stream.
2197 First input stream will be processed depending on second stream signal.
2198 The filtered signal then can be filtered with other filters in later stages of
2199 processing. See @ref{pan} and @ref{amerge} filter.
2201 The filter accepts the following options:
2205 If a signal of second stream raises above this level it will affect the gain
2206 reduction of first stream.
2207 By default is 0.125. Range is between 0.00097563 and 1.
2210 Set a ratio about which the signal is reduced. 1:2 means that if the level
2211 raised 4dB above the threshold, it will be only 2dB above after the reduction.
2212 Default is 2. Range is between 1 and 20.
2215 Amount of milliseconds the signal has to rise above the threshold before gain
2216 reduction starts. Default is 20. Range is between 0.01 and 2000.
2219 Amount of milliseconds the signal has to fall bellow the threshold before
2220 reduction is decreased again. Default is 250. Range is between 0.01 and 9000.
2223 Set the amount by how much signal will be amplified after processing.
2224 Default is 2. Range is from 1 and 64.
2227 Curve the sharp knee around the threshold to enter gain reduction more softly.
2228 Default is 2.82843. Range is between 1 and 8.
2231 Choose if the @code{average} level between all channels of side-chain stream
2232 or the louder(@code{maximum}) channel of side-chain stream affects the
2233 reduction. Default is @code{average}.
2236 Should the exact signal be taken in case of @code{peak} or an RMS one in case
2237 of @code{rms}. Default is @code{rms} which is mainly smoother.
2240 @subsection Examples
2244 Full ffmpeg example taking 2 audio inputs, 1st input to be compressed
2245 depending on the signal of 2nd input and later compressed signal to be
2246 merged with 2nd input:
2248 ffmpeg -i main.flac -i sidechain.flac -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress[compr];[compr][mix]amerge"
2252 @section silencedetect
2254 Detect silence in an audio stream.
2256 This filter logs a message when it detects that the input audio volume is less
2257 or equal to a noise tolerance value for a duration greater or equal to the
2258 minimum detected noise duration.
2260 The printed times and duration are expressed in seconds.
2262 The filter accepts the following options:
2266 Set silence duration until notification (default is 2 seconds).
2269 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
2270 specified value) or amplitude ratio. Default is -60dB, or 0.001.
2273 @subsection Examples
2277 Detect 5 seconds of silence with -50dB noise tolerance:
2279 silencedetect=n=-50dB:d=5
2283 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
2284 tolerance in @file{silence.mp3}:
2286 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
2290 @section silenceremove
2292 Remove silence from the beginning, middle or end of the audio.
2294 The filter accepts the following options:
2298 This value is used to indicate if audio should be trimmed at beginning of
2299 the audio. A value of zero indicates no silence should be trimmed from the
2300 beginning. When specifying a non-zero value, it trims audio up until it
2301 finds non-silence. Normally, when trimming silence from beginning of audio
2302 the @var{start_periods} will be @code{1} but it can be increased to higher
2303 values to trim all audio up to specific count of non-silence periods.
2304 Default value is @code{0}.
2306 @item start_duration
2307 Specify the amount of time that non-silence must be detected before it stops
2308 trimming audio. By increasing the duration, bursts of noises can be treated
2309 as silence and trimmed off. Default value is @code{0}.
2311 @item start_threshold
2312 This indicates what sample value should be treated as silence. For digital
2313 audio, a value of @code{0} may be fine but for audio recorded from analog,
2314 you may wish to increase the value to account for background noise.
2315 Can be specified in dB (in case "dB" is appended to the specified value)
2316 or amplitude ratio. Default value is @code{0}.
2319 Set the count for trimming silence from the end of audio.
2320 To remove silence from the middle of a file, specify a @var{stop_periods}
2321 that is negative. This value is then treated as a positive value and is
2322 used to indicate the effect should restart processing as specified by
2323 @var{start_periods}, making it suitable for removing periods of silence
2324 in the middle of the audio.
2325 Default value is @code{0}.
2328 Specify a duration of silence that must exist before audio is not copied any
2329 more. By specifying a higher duration, silence that is wanted can be left in
2331 Default value is @code{0}.
2333 @item stop_threshold
2334 This is the same as @option{start_threshold} but for trimming silence from
2336 Can be specified in dB (in case "dB" is appended to the specified value)
2337 or amplitude ratio. Default value is @code{0}.
2340 This indicate that @var{stop_duration} length of audio should be left intact
2341 at the beginning of each period of silence.
2342 For example, if you want to remove long pauses between words but do not want
2343 to remove the pauses completely. Default value is @code{0}.
2347 @subsection Examples
2351 The following example shows how this filter can be used to start a recording
2352 that does not contain the delay at the start which usually occurs between
2353 pressing the record button and the start of the performance:
2355 silenceremove=1:5:0.02
2361 Boost or cut treble (upper) frequencies of the audio using a two-pole
2362 shelving filter with a response similar to that of a standard
2363 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
2365 The filter accepts the following options:
2369 Give the gain at whichever is the lower of ~22 kHz and the
2370 Nyquist frequency. Its useful range is about -20 (for a large cut)
2371 to +20 (for a large boost). Beware of clipping when using a positive gain.
2374 Set the filter's central frequency and so can be used
2375 to extend or reduce the frequency range to be boosted or cut.
2376 The default value is @code{3000} Hz.
2379 Set method to specify band-width of filter.
2392 Determine how steep is the filter's shelf transition.
2397 Adjust the input audio volume.
2399 It accepts the following parameters:
2403 Set audio volume expression.
2405 Output values are clipped to the maximum value.
2407 The output audio volume is given by the relation:
2409 @var{output_volume} = @var{volume} * @var{input_volume}
2412 The default value for @var{volume} is "1.0".
2415 This parameter represents the mathematical precision.
2417 It determines which input sample formats will be allowed, which affects the
2418 precision of the volume scaling.
2422 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
2424 32-bit floating-point; this limits input sample format to FLT. (default)
2426 64-bit floating-point; this limits input sample format to DBL.
2430 Choose the behaviour on encountering ReplayGain side data in input frames.
2434 Remove ReplayGain side data, ignoring its contents (the default).
2437 Ignore ReplayGain side data, but leave it in the frame.
2440 Prefer the track gain, if present.
2443 Prefer the album gain, if present.
2446 @item replaygain_preamp
2447 Pre-amplification gain in dB to apply to the selected replaygain gain.
2449 Default value for @var{replaygain_preamp} is 0.0.
2452 Set when the volume expression is evaluated.
2454 It accepts the following values:
2457 only evaluate expression once during the filter initialization, or
2458 when the @samp{volume} command is sent
2461 evaluate expression for each incoming frame
2464 Default value is @samp{once}.
2467 The volume expression can contain the following parameters.
2471 frame number (starting at zero)
2474 @item nb_consumed_samples
2475 number of samples consumed by the filter
2477 number of samples in the current frame
2479 original frame position in the file
2485 PTS at start of stream
2487 time at start of stream
2493 last set volume value
2496 Note that when @option{eval} is set to @samp{once} only the
2497 @var{sample_rate} and @var{tb} variables are available, all other
2498 variables will evaluate to NAN.
2500 @subsection Commands
2502 This filter supports the following commands:
2505 Modify the volume expression.
2506 The command accepts the same syntax of the corresponding option.
2508 If the specified expression is not valid, it is kept at its current
2510 @item replaygain_noclip
2511 Prevent clipping by limiting the gain applied.
2513 Default value for @var{replaygain_noclip} is 1.
2517 @subsection Examples
2521 Halve the input audio volume:
2525 volume=volume=-6.0206dB
2528 In all the above example the named key for @option{volume} can be
2529 omitted, for example like in:
2535 Increase input audio power by 6 decibels using fixed-point precision:
2537 volume=volume=6dB:precision=fixed
2541 Fade volume after time 10 with an annihilation period of 5 seconds:
2543 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
2547 @section volumedetect
2549 Detect the volume of the input video.
2551 The filter has no parameters. The input is not modified. Statistics about
2552 the volume will be printed in the log when the input stream end is reached.
2554 In particular it will show the mean volume (root mean square), maximum
2555 volume (on a per-sample basis), and the beginning of a histogram of the
2556 registered volume values (from the maximum value to a cumulated 1/1000 of
2559 All volumes are in decibels relative to the maximum PCM value.
2561 @subsection Examples
2563 Here is an excerpt of the output:
2565 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2566 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2567 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2568 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2569 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2570 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2571 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2572 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2573 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2579 The mean square energy is approximately -27 dB, or 10^-2.7.
2581 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2583 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2586 In other words, raising the volume by +4 dB does not cause any clipping,
2587 raising it by +5 dB causes clipping for 6 samples, etc.
2589 @c man end AUDIO FILTERS
2591 @chapter Audio Sources
2592 @c man begin AUDIO SOURCES
2594 Below is a description of the currently available audio sources.
2598 Buffer audio frames, and make them available to the filter chain.
2600 This source is mainly intended for a programmatic use, in particular
2601 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2603 It accepts the following parameters:
2607 The timebase which will be used for timestamps of submitted frames. It must be
2608 either a floating-point number or in @var{numerator}/@var{denominator} form.
2611 The sample rate of the incoming audio buffers.
2614 The sample format of the incoming audio buffers.
2615 Either a sample format name or its corresponding integer representation from
2616 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2618 @item channel_layout
2619 The channel layout of the incoming audio buffers.
2620 Either a channel layout name from channel_layout_map in
2621 @file{libavutil/channel_layout.c} or its corresponding integer representation
2622 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2625 The number of channels of the incoming audio buffers.
2626 If both @var{channels} and @var{channel_layout} are specified, then they
2631 @subsection Examples
2634 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2637 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2638 Since the sample format with name "s16p" corresponds to the number
2639 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2642 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2647 Generate an audio signal specified by an expression.
2649 This source accepts in input one or more expressions (one for each
2650 channel), which are evaluated and used to generate a corresponding
2653 This source accepts the following options:
2657 Set the '|'-separated expressions list for each separate channel. In case the
2658 @option{channel_layout} option is not specified, the selected channel layout
2659 depends on the number of provided expressions. Otherwise the last
2660 specified expression is applied to the remaining output channels.
2662 @item channel_layout, c
2663 Set the channel layout. The number of channels in the specified layout
2664 must be equal to the number of specified expressions.
2667 Set the minimum duration of the sourced audio. See
2668 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2669 for the accepted syntax.
2670 Note that the resulting duration may be greater than the specified
2671 duration, as the generated audio is always cut at the end of a
2674 If not specified, or the expressed duration is negative, the audio is
2675 supposed to be generated forever.
2678 Set the number of samples per channel per each output frame,
2681 @item sample_rate, s
2682 Specify the sample rate, default to 44100.
2685 Each expression in @var{exprs} can contain the following constants:
2689 number of the evaluated sample, starting from 0
2692 time of the evaluated sample expressed in seconds, starting from 0
2699 @subsection Examples
2709 Generate a sin signal with frequency of 440 Hz, set sample rate to
2712 aevalsrc="sin(440*2*PI*t):s=8000"
2716 Generate a two channels signal, specify the channel layout (Front
2717 Center + Back Center) explicitly:
2719 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2723 Generate white noise:
2725 aevalsrc="-2+random(0)"
2729 Generate an amplitude modulated signal:
2731 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2735 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2737 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2744 The null audio source, return unprocessed audio frames. It is mainly useful
2745 as a template and to be employed in analysis / debugging tools, or as
2746 the source for filters which ignore the input data (for example the sox
2749 This source accepts the following options:
2753 @item channel_layout, cl
2755 Specifies the channel layout, and can be either an integer or a string
2756 representing a channel layout. The default value of @var{channel_layout}
2759 Check the channel_layout_map definition in
2760 @file{libavutil/channel_layout.c} for the mapping between strings and
2761 channel layout values.
2763 @item sample_rate, r
2764 Specifies the sample rate, and defaults to 44100.
2767 Set the number of samples per requested frames.
2771 @subsection Examples
2775 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2777 anullsrc=r=48000:cl=4
2781 Do the same operation with a more obvious syntax:
2783 anullsrc=r=48000:cl=mono
2787 All the parameters need to be explicitly defined.
2791 Synthesize a voice utterance using the libflite library.
2793 To enable compilation of this filter you need to configure FFmpeg with
2794 @code{--enable-libflite}.
2796 Note that the flite library is not thread-safe.
2798 The filter accepts the following options:
2803 If set to 1, list the names of the available voices and exit
2804 immediately. Default value is 0.
2807 Set the maximum number of samples per frame. Default value is 512.
2810 Set the filename containing the text to speak.
2813 Set the text to speak.
2816 Set the voice to use for the speech synthesis. Default value is
2817 @code{kal}. See also the @var{list_voices} option.
2820 @subsection Examples
2824 Read from file @file{speech.txt}, and synthesize the text using the
2825 standard flite voice:
2827 flite=textfile=speech.txt
2831 Read the specified text selecting the @code{slt} voice:
2833 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2837 Input text to ffmpeg:
2839 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2843 Make @file{ffplay} speak the specified text, using @code{flite} and
2844 the @code{lavfi} device:
2846 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2850 For more information about libflite, check:
2851 @url{http://www.speech.cs.cmu.edu/flite/}
2855 Generate an audio signal made of a sine wave with amplitude 1/8.
2857 The audio signal is bit-exact.
2859 The filter accepts the following options:
2864 Set the carrier frequency. Default is 440 Hz.
2866 @item beep_factor, b
2867 Enable a periodic beep every second with frequency @var{beep_factor} times
2868 the carrier frequency. Default is 0, meaning the beep is disabled.
2870 @item sample_rate, r
2871 Specify the sample rate, default is 44100.
2874 Specify the duration of the generated audio stream.
2876 @item samples_per_frame
2877 Set the number of samples per output frame.
2879 The expression can contain the following constants:
2883 The (sequential) number of the output audio frame, starting from 0.
2886 The PTS (Presentation TimeStamp) of the output audio frame,
2887 expressed in @var{TB} units.
2890 The PTS of the output audio frame, expressed in seconds.
2893 The timebase of the output audio frames.
2896 Default is @code{1024}.
2899 @subsection Examples
2904 Generate a simple 440 Hz sine wave:
2910 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2914 sine=frequency=220:beep_factor=4:duration=5
2918 Generate a 1 kHz sine wave following @code{1602,1601,1602,1601,1602} NTSC
2921 sine=1000:samples_per_frame='st(0,mod(n,5)); 1602-not(not(eq(ld(0),1)+eq(ld(0),3)))'
2925 @c man end AUDIO SOURCES
2927 @chapter Audio Sinks
2928 @c man begin AUDIO SINKS
2930 Below is a description of the currently available audio sinks.
2932 @section abuffersink
2934 Buffer audio frames, and make them available to the end of filter chain.
2936 This sink is mainly intended for programmatic use, in particular
2937 through the interface defined in @file{libavfilter/buffersink.h}
2938 or the options system.
2940 It accepts a pointer to an AVABufferSinkContext structure, which
2941 defines the incoming buffers' formats, to be passed as the opaque
2942 parameter to @code{avfilter_init_filter} for initialization.
2945 Null audio sink; do absolutely nothing with the input audio. It is
2946 mainly useful as a template and for use in analysis / debugging
2949 @c man end AUDIO SINKS
2951 @chapter Video Filters
2952 @c man begin VIDEO FILTERS
2954 When you configure your FFmpeg build, you can disable any of the
2955 existing filters using @code{--disable-filters}.
2956 The configure output will show the video filters included in your
2959 Below is a description of the currently available video filters.
2961 @section alphaextract
2963 Extract the alpha component from the input as a grayscale video. This
2964 is especially useful with the @var{alphamerge} filter.
2968 Add or replace the alpha component of the primary input with the
2969 grayscale value of a second input. This is intended for use with
2970 @var{alphaextract} to allow the transmission or storage of frame
2971 sequences that have alpha in a format that doesn't support an alpha
2974 For example, to reconstruct full frames from a normal YUV-encoded video
2975 and a separate video created with @var{alphaextract}, you might use:
2977 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2980 Since this filter is designed for reconstruction, it operates on frame
2981 sequences without considering timestamps, and terminates when either
2982 input reaches end of stream. This will cause problems if your encoding
2983 pipeline drops frames. If you're trying to apply an image as an
2984 overlay to a video stream, consider the @var{overlay} filter instead.
2988 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2989 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2990 Substation Alpha) subtitles files.
2992 This filter accepts the following option in addition to the common options from
2993 the @ref{subtitles} filter:
2997 Set the shaping engine
2999 Available values are:
3002 The default libass shaping engine, which is the best available.
3004 Fast, font-agnostic shaper that can do only substitutions
3006 Slower shaper using OpenType for substitutions and positioning
3009 The default is @code{auto}.
3013 Apply an Adaptive Temporal Averaging Denoiser to the video input.
3015 The filter accepts the following options:
3019 Set threshold A for 1st plane. Default is 0.02.
3020 Valid range is 0 to 0.3.
3023 Set threshold B for 1st plane. Default is 0.04.
3024 Valid range is 0 to 5.
3027 Set threshold A for 2nd plane. Default is 0.02.
3028 Valid range is 0 to 0.3.
3031 Set threshold B for 2nd plane. Default is 0.04.
3032 Valid range is 0 to 5.
3035 Set threshold A for 3rd plane. Default is 0.02.
3036 Valid range is 0 to 0.3.
3039 Set threshold B for 3rd plane. Default is 0.04.
3040 Valid range is 0 to 5.
3042 Threshold A is designed to react on abrupt changes in the input signal and
3043 threshold B is designed to react on continuous changes in the input signal.
3046 Set number of frames filter will use for averaging. Default is 33. Must be odd
3047 number in range [5, 129].
3052 Compute the bounding box for the non-black pixels in the input frame
3055 This filter computes the bounding box containing all the pixels with a
3056 luminance value greater than the minimum allowed value.
3057 The parameters describing the bounding box are printed on the filter
3060 The filter accepts the following option:
3064 Set the minimal luminance value. Default is @code{16}.
3067 @section blackdetect
3069 Detect video intervals that are (almost) completely black. Can be
3070 useful to detect chapter transitions, commercials, or invalid
3071 recordings. Output lines contains the time for the start, end and
3072 duration of the detected black interval expressed in seconds.
3074 In order to display the output lines, you need to set the loglevel at
3075 least to the AV_LOG_INFO value.
3077 The filter accepts the following options:
3080 @item black_min_duration, d
3081 Set the minimum detected black duration expressed in seconds. It must
3082 be a non-negative floating point number.
3084 Default value is 2.0.
3086 @item picture_black_ratio_th, pic_th
3087 Set the threshold for considering a picture "black".
3088 Express the minimum value for the ratio:
3090 @var{nb_black_pixels} / @var{nb_pixels}
3093 for which a picture is considered black.
3094 Default value is 0.98.
3096 @item pixel_black_th, pix_th
3097 Set the threshold for considering a pixel "black".
3099 The threshold expresses the maximum pixel luminance value for which a
3100 pixel is considered "black". The provided value is scaled according to
3101 the following equation:
3103 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
3106 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
3107 the input video format, the range is [0-255] for YUV full-range
3108 formats and [16-235] for YUV non full-range formats.
3110 Default value is 0.10.
3113 The following example sets the maximum pixel threshold to the minimum
3114 value, and detects only black intervals of 2 or more seconds:
3116 blackdetect=d=2:pix_th=0.00
3121 Detect frames that are (almost) completely black. Can be useful to
3122 detect chapter transitions or commercials. Output lines consist of
3123 the frame number of the detected frame, the percentage of blackness,
3124 the position in the file if known or -1 and the timestamp in seconds.
3126 In order to display the output lines, you need to set the loglevel at
3127 least to the AV_LOG_INFO value.
3129 It accepts the following parameters:
3134 The percentage of the pixels that have to be below the threshold; it defaults to
3137 @item threshold, thresh
3138 The threshold below which a pixel value is considered black; it defaults to
3143 @section blend, tblend
3145 Blend two video frames into each other.
3147 The @code{blend} filter takes two input streams and outputs one
3148 stream, the first input is the "top" layer and second input is
3149 "bottom" layer. Output terminates when shortest input terminates.
3151 The @code{tblend} (time blend) filter takes two consecutive frames
3152 from one single stream, and outputs the result obtained by blending
3153 the new frame on top of the old frame.
3155 A description of the accepted options follows.
3163 Set blend mode for specific pixel component or all pixel components in case
3164 of @var{all_mode}. Default value is @code{normal}.
3166 Available values for component modes are:
3203 Set blend opacity for specific pixel component or all pixel components in case
3204 of @var{all_opacity}. Only used in combination with pixel component blend modes.
3211 Set blend expression for specific pixel component or all pixel components in case
3212 of @var{all_expr}. Note that related mode options will be ignored if those are set.
3214 The expressions can use the following variables:
3218 The sequential number of the filtered frame, starting from @code{0}.
3222 the coordinates of the current sample
3226 the width and height of currently filtered plane
3230 Width and height scale depending on the currently filtered plane. It is the
3231 ratio between the corresponding luma plane number of pixels and the current
3232 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
3233 @code{0.5,0.5} for chroma planes.
3236 Time of the current frame, expressed in seconds.
3239 Value of pixel component at current location for first video frame (top layer).
3242 Value of pixel component at current location for second video frame (bottom layer).
3246 Force termination when the shortest input terminates. Default is
3247 @code{0}. This option is only defined for the @code{blend} filter.
3250 Continue applying the last bottom frame after the end of the stream. A value of
3251 @code{0} disable the filter after the last frame of the bottom layer is reached.
3252 Default is @code{1}. This option is only defined for the @code{blend} filter.
3255 @subsection Examples
3259 Apply transition from bottom layer to top layer in first 10 seconds:
3261 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
3265 Apply 1x1 checkerboard effect:
3267 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
3271 Apply uncover left effect:
3273 blend=all_expr='if(gte(N*SW+X,W),A,B)'
3277 Apply uncover down effect:
3279 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
3283 Apply uncover up-left effect:
3285 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
3289 Display differences between the current and the previous frame:
3291 tblend=all_mode=difference128
3297 Apply a boxblur algorithm to the input video.
3299 It accepts the following parameters:
3303 @item luma_radius, lr
3304 @item luma_power, lp
3305 @item chroma_radius, cr
3306 @item chroma_power, cp
3307 @item alpha_radius, ar
3308 @item alpha_power, ap
3312 A description of the accepted options follows.
3315 @item luma_radius, lr
3316 @item chroma_radius, cr
3317 @item alpha_radius, ar
3318 Set an expression for the box radius in pixels used for blurring the
3319 corresponding input plane.
3321 The radius value must be a non-negative number, and must not be
3322 greater than the value of the expression @code{min(w,h)/2} for the
3323 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
3326 Default value for @option{luma_radius} is "2". If not specified,
3327 @option{chroma_radius} and @option{alpha_radius} default to the
3328 corresponding value set for @option{luma_radius}.
3330 The expressions can contain the following constants:
3334 The input width and height in pixels.
3338 The input chroma image width and height in pixels.
3342 The horizontal and vertical chroma subsample values. For example, for the
3343 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
3346 @item luma_power, lp
3347 @item chroma_power, cp
3348 @item alpha_power, ap
3349 Specify how many times the boxblur filter is applied to the
3350 corresponding plane.
3352 Default value for @option{luma_power} is 2. If not specified,
3353 @option{chroma_power} and @option{alpha_power} default to the
3354 corresponding value set for @option{luma_power}.
3356 A value of 0 will disable the effect.
3359 @subsection Examples
3363 Apply a boxblur filter with the luma, chroma, and alpha radii
3366 boxblur=luma_radius=2:luma_power=1
3371 Set the luma radius to 2, and alpha and chroma radius to 0:
3373 boxblur=2:1:cr=0:ar=0
3377 Set the luma and chroma radii to a fraction of the video dimension:
3379 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
3385 Visualize information exported by some codecs.
3387 Some codecs can export information through frames using side-data or other
3388 means. For example, some MPEG based codecs export motion vectors through the
3389 @var{export_mvs} flag in the codec @option{flags2} option.
3391 The filter accepts the following option:
3395 Set motion vectors to visualize.
3397 Available flags for @var{mv} are:
3401 forward predicted MVs of P-frames
3403 forward predicted MVs of B-frames
3405 backward predicted MVs of B-frames
3409 @subsection Examples
3413 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
3415 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
3419 @section colorbalance
3420 Modify intensity of primary colors (red, green and blue) of input frames.
3422 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
3423 regions for the red-cyan, green-magenta or blue-yellow balance.
3425 A positive adjustment value shifts the balance towards the primary color, a negative
3426 value towards the complementary color.
3428 The filter accepts the following options:
3434 Adjust red, green and blue shadows (darkest pixels).
3439 Adjust red, green and blue midtones (medium pixels).
3444 Adjust red, green and blue highlights (brightest pixels).
3446 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
3449 @subsection Examples
3453 Add red color cast to shadows:
3460 RGB colorspace color keying.
3462 The filter accepts the following options:
3466 The color which will be replaced with transparency.
3469 Similarity percentage with the key color.
3471 0.01 matches only the exact key color, while 1.0 matches everything.
3476 0.0 makes pixels either fully transparent, or not transparent at all.
3478 Higher values result in semi-transparent pixels, with a higher transparency
3479 the more similar the pixels color is to the key color.
3482 @subsection Examples
3486 Make every green pixel in the input image transparent:
3488 ffmpeg -i input.png -vf colorkey=green out.png
3492 Overlay a greenscreen-video on top of a static background image.
3494 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
3498 @section colorlevels
3500 Adjust video input frames using levels.
3502 The filter accepts the following options:
3509 Adjust red, green, blue and alpha input black point.
3510 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
3516 Adjust red, green, blue and alpha input white point.
3517 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{1}.
3519 Input levels are used to lighten highlights (bright tones), darken shadows
3520 (dark tones), change the balance of bright and dark tones.
3526 Adjust red, green, blue and alpha output black point.
3527 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{0}.
3533 Adjust red, green, blue and alpha output white point.
3534 Allowed ranges for options are @code{[0, 1.0]}. Defaults are @code{1}.
3536 Output levels allows manual selection of a constrained output level range.
3539 @subsection Examples
3543 Make video output darker:
3545 colorlevels=rimin=0.058:gimin=0.058:bimin=0.058
3551 colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96
3555 Make video output lighter:
3557 colorlevels=rimax=0.902:gimax=0.902:bimax=0.902
3561 Increase brightness:
3563 colorlevels=romin=0.5:gomin=0.5:bomin=0.5
3567 @section colorchannelmixer
3569 Adjust video input frames by re-mixing color channels.
3571 This filter modifies a color channel by adding the values associated to
3572 the other channels of the same pixels. For example if the value to
3573 modify is red, the output value will be:
3575 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
3578 The filter accepts the following options:
3585 Adjust contribution of input red, green, blue and alpha channels for output red channel.
3586 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
3592 Adjust contribution of input red, green, blue and alpha channels for output green channel.
3593 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
3599 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
3600 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
3606 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
3607 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
3609 Allowed ranges for options are @code{[-2.0, 2.0]}.
3612 @subsection Examples
3616 Convert source to grayscale:
3618 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
3621 Simulate sepia tones:
3623 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
3627 @section colormatrix
3629 Convert color matrix.
3631 The filter accepts the following options:
3636 Specify the source and destination color matrix. Both values must be
3639 The accepted values are:
3655 For example to convert from BT.601 to SMPTE-240M, use the command:
3657 colormatrix=bt601:smpte240m
3662 Copy the input source unchanged to the output. This is mainly useful for
3667 Crop the input video to given dimensions.
3669 It accepts the following parameters:
3673 The width of the output video. It defaults to @code{iw}.
3674 This expression is evaluated only once during the filter
3675 configuration, or when the @samp{w} or @samp{out_w} command is sent.
3678 The height of the output video. It defaults to @code{ih}.
3679 This expression is evaluated only once during the filter
3680 configuration, or when the @samp{h} or @samp{out_h} command is sent.
3683 The horizontal position, in the input video, of the left edge of the output
3684 video. It defaults to @code{(in_w-out_w)/2}.
3685 This expression is evaluated per-frame.
3688 The vertical position, in the input video, of the top edge of the output video.
3689 It defaults to @code{(in_h-out_h)/2}.
3690 This expression is evaluated per-frame.
3693 If set to 1 will force the output display aspect ratio
3694 to be the same of the input, by changing the output sample aspect
3695 ratio. It defaults to 0.
3698 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
3699 expressions containing the following constants:
3704 The computed values for @var{x} and @var{y}. They are evaluated for
3709 The input width and height.
3713 These are the same as @var{in_w} and @var{in_h}.
3717 The output (cropped) width and height.
3721 These are the same as @var{out_w} and @var{out_h}.
3724 same as @var{iw} / @var{ih}
3727 input sample aspect ratio
3730 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
3734 horizontal and vertical chroma subsample values. For example for the
3735 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3738 The number of the input frame, starting from 0.
3741 the position in the file of the input frame, NAN if unknown
3744 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
3748 The expression for @var{out_w} may depend on the value of @var{out_h},
3749 and the expression for @var{out_h} may depend on @var{out_w}, but they
3750 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
3751 evaluated after @var{out_w} and @var{out_h}.
3753 The @var{x} and @var{y} parameters specify the expressions for the
3754 position of the top-left corner of the output (non-cropped) area. They
3755 are evaluated for each frame. If the evaluated value is not valid, it
3756 is approximated to the nearest valid value.
3758 The expression for @var{x} may depend on @var{y}, and the expression
3759 for @var{y} may depend on @var{x}.
3761 @subsection Examples
3765 Crop area with size 100x100 at position (12,34).
3770 Using named options, the example above becomes:
3772 crop=w=100:h=100:x=12:y=34
3776 Crop the central input area with size 100x100:
3782 Crop the central input area with size 2/3 of the input video:
3784 crop=2/3*in_w:2/3*in_h
3788 Crop the input video central square:
3795 Delimit the rectangle with the top-left corner placed at position
3796 100:100 and the right-bottom corner corresponding to the right-bottom
3797 corner of the input image.
3799 crop=in_w-100:in_h-100:100:100
3803 Crop 10 pixels from the left and right borders, and 20 pixels from
3804 the top and bottom borders
3806 crop=in_w-2*10:in_h-2*20
3810 Keep only the bottom right quarter of the input image:
3812 crop=in_w/2:in_h/2:in_w/2:in_h/2
3816 Crop height for getting Greek harmony:
3818 crop=in_w:1/PHI*in_w
3822 Apply trembling effect:
3824 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)
3828 Apply erratic camera effect depending on timestamp:
3830 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)"
3834 Set x depending on the value of y:
3836 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3840 @subsection Commands
3842 This filter supports the following commands:
3848 Set width/height of the output video and the horizontal/vertical position
3850 The command accepts the same syntax of the corresponding option.
3852 If the specified expression is not valid, it is kept at its current
3858 Auto-detect the crop size.
3860 It calculates the necessary cropping parameters and prints the
3861 recommended parameters via the logging system. The detected dimensions
3862 correspond to the non-black area of the input video.
3864 It accepts the following parameters:
3869 Set higher black value threshold, which can be optionally specified
3870 from nothing (0) to everything (255 for 8bit based formats). An intensity
3871 value greater to the set value is considered non-black. It defaults to 24.
3872 You can also specify a value between 0.0 and 1.0 which will be scaled depending
3873 on the bitdepth of the pixel format.
3876 The value which the width/height should be divisible by. It defaults to
3877 16. The offset is automatically adjusted to center the video. Use 2 to
3878 get only even dimensions (needed for 4:2:2 video). 16 is best when
3879 encoding to most video codecs.
3881 @item reset_count, reset
3882 Set the counter that determines after how many frames cropdetect will
3883 reset the previously detected largest video area and start over to
3884 detect the current optimal crop area. Default value is 0.
3886 This can be useful when channel logos distort the video area. 0
3887 indicates 'never reset', and returns the largest area encountered during
3894 Apply color adjustments using curves.
3896 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3897 component (red, green and blue) has its values defined by @var{N} key points
3898 tied from each other using a smooth curve. The x-axis represents the pixel
3899 values from the input frame, and the y-axis the new pixel values to be set for
3902 By default, a component curve is defined by the two points @var{(0;0)} and
3903 @var{(1;1)}. This creates a straight line where each original pixel value is
3904 "adjusted" to its own value, which means no change to the image.
3906 The filter allows you to redefine these two points and add some more. A new
3907 curve (using a natural cubic spline interpolation) will be define to pass
3908 smoothly through all these new coordinates. The new defined points needs to be
3909 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3910 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3911 the vector spaces, the values will be clipped accordingly.
3913 If there is no key point defined in @code{x=0}, the filter will automatically
3914 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3915 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3917 The filter accepts the following options:
3921 Select one of the available color presets. This option can be used in addition
3922 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3923 options takes priority on the preset values.
3924 Available presets are:
3927 @item color_negative
3930 @item increase_contrast
3932 @item linear_contrast
3933 @item medium_contrast
3935 @item strong_contrast
3938 Default is @code{none}.
3940 Set the master key points. These points will define a second pass mapping. It
3941 is sometimes called a "luminance" or "value" mapping. It can be used with
3942 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3943 post-processing LUT.
3945 Set the key points for the red component.
3947 Set the key points for the green component.
3949 Set the key points for the blue component.
3951 Set the key points for all components (not including master).
3952 Can be used in addition to the other key points component
3953 options. In this case, the unset component(s) will fallback on this
3954 @option{all} setting.
3956 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3959 To avoid some filtergraph syntax conflicts, each key points list need to be
3960 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3962 @subsection Examples
3966 Increase slightly the middle level of blue:
3968 curves=blue='0.5/0.58'
3974 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3976 Here we obtain the following coordinates for each components:
3979 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3981 @code{(0;0) (0.50;0.48) (1;1)}
3983 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3987 The previous example can also be achieved with the associated built-in preset:
3989 curves=preset=vintage
3999 Use a Photoshop preset and redefine the points of the green component:
4001 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
4007 Denoise frames using 2D DCT (frequency domain filtering).
4009 This filter is not designed for real time.
4011 The filter accepts the following options:
4015 Set the noise sigma constant.
4017 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
4018 coefficient (absolute value) below this threshold with be dropped.
4020 If you need a more advanced filtering, see @option{expr}.
4022 Default is @code{0}.
4025 Set number overlapping pixels for each block. Since the filter can be slow, you
4026 may want to reduce this value, at the cost of a less effective filter and the
4027 risk of various artefacts.
4029 If the overlapping value doesn't permit processing the whole input width or
4030 height, a warning will be displayed and according borders won't be denoised.
4032 Default value is @var{blocksize}-1, which is the best possible setting.
4035 Set the coefficient factor expression.
4037 For each coefficient of a DCT block, this expression will be evaluated as a
4038 multiplier value for the coefficient.
4040 If this is option is set, the @option{sigma} option will be ignored.
4042 The absolute value of the coefficient can be accessed through the @var{c}
4046 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
4047 @var{blocksize}, which is the width and height of the processed blocks.
4049 The default value is @var{3} (8x8) and can be raised to @var{4} for a
4050 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
4051 on the speed processing. Also, a larger block size does not necessarily means a
4055 @subsection Examples
4057 Apply a denoise with a @option{sigma} of @code{4.5}:
4062 The same operation can be achieved using the expression system:
4064 dctdnoiz=e='gte(c, 4.5*3)'
4067 Violent denoise using a block size of @code{16x16}:
4074 Remove banding artifacts from input video.
4075 It works by replacing banded pixels with average value of referenced pixels.
4077 The filter accepts the following options:
4084 Set banding detection threshold for each plane. Default is 0.02.
4085 Valid range is 0.00003 to 0.5.
4086 If difference between current pixel and reference pixel is less than threshold,
4087 it will be considered as banded.
4090 Banding detection range in pixels. Default is 16. If positive, random number
4091 in range 0 to set value will be used. If negative, exact absolute value
4093 The range defines square of four pixels around current pixel.
4096 Set direction in radians from which four pixel will be compared. If positive,
4097 random direction from 0 to set direction will be picked. If negative, exact of
4098 absolute value will be picked. For example direction 0, -PI or -2*PI radians
4099 will pick only pixels on same row and -PI/2 will pick only pixels on same
4103 If enabled, current pixel is compared with average value of all four
4104 surrounding pixels. The default is enabled. If disabled current pixel is
4105 compared with all four surrounding pixels. The pixel is considered banded
4106 if only all four differences with surrounding pixels are less than threshold.
4112 Drop duplicated frames at regular intervals.
4114 The filter accepts the following options:
4118 Set the number of frames from which one will be dropped. Setting this to
4119 @var{N} means one frame in every batch of @var{N} frames will be dropped.
4120 Default is @code{5}.
4123 Set the threshold for duplicate detection. If the difference metric for a frame
4124 is less than or equal to this value, then it is declared as duplicate. Default
4128 Set scene change threshold. Default is @code{15}.
4132 Set the size of the x and y-axis blocks used during metric calculations.
4133 Larger blocks give better noise suppression, but also give worse detection of
4134 small movements. Must be a power of two. Default is @code{32}.
4137 Mark main input as a pre-processed input and activate clean source input
4138 stream. This allows the input to be pre-processed with various filters to help
4139 the metrics calculation while keeping the frame selection lossless. When set to
4140 @code{1}, the first stream is for the pre-processed input, and the second
4141 stream is the clean source from where the kept frames are chosen. Default is
4145 Set whether or not chroma is considered in the metric calculations. Default is
4151 Apply deflate effect to the video.
4153 This filter replaces the pixel by the local(3x3) average by taking into account
4154 only values lower than the pixel.
4156 It accepts the following options:
4163 Allows to limit the maximum change for each plane, default is 65535.
4164 If 0, plane will remain unchanged.
4169 Remove judder produced by partially interlaced telecined content.
4171 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
4172 source was partially telecined content then the output of @code{pullup,dejudder}
4173 will have a variable frame rate. May change the recorded frame rate of the
4174 container. Aside from that change, this filter will not affect constant frame
4177 The option available in this filter is:
4181 Specify the length of the window over which the judder repeats.
4183 Accepts any integer greater than 1. Useful values are:
4187 If the original was telecined from 24 to 30 fps (Film to NTSC).
4190 If the original was telecined from 25 to 30 fps (PAL to NTSC).
4193 If a mixture of the two.
4196 The default is @samp{4}.
4201 Suppress a TV station logo by a simple interpolation of the surrounding
4202 pixels. Just set a rectangle covering the logo and watch it disappear
4203 (and sometimes something even uglier appear - your mileage may vary).
4205 It accepts the following parameters:
4210 Specify the top left corner coordinates of the logo. They must be
4215 Specify the width and height of the logo to clear. They must be
4219 Specify the thickness of the fuzzy edge of the rectangle (added to
4220 @var{w} and @var{h}). The default value is 4.
4223 When set to 1, a green rectangle is drawn on the screen to simplify
4224 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
4225 The default value is 0.
4227 The rectangle is drawn on the outermost pixels which will be (partly)
4228 replaced with interpolated values. The values of the next pixels
4229 immediately outside this rectangle in each direction will be used to
4230 compute the interpolated pixel values inside the rectangle.
4234 @subsection Examples
4238 Set a rectangle covering the area with top left corner coordinates 0,0
4239 and size 100x77, and a band of size 10:
4241 delogo=x=0:y=0:w=100:h=77:band=10
4248 Attempt to fix small changes in horizontal and/or vertical shift. This
4249 filter helps remove camera shake from hand-holding a camera, bumping a
4250 tripod, moving on a vehicle, etc.
4252 The filter accepts the following options:
4260 Specify a rectangular area where to limit the search for motion
4262 If desired the search for motion vectors can be limited to a
4263 rectangular area of the frame defined by its top left corner, width
4264 and height. These parameters have the same meaning as the drawbox
4265 filter which can be used to visualise the position of the bounding
4268 This is useful when simultaneous movement of subjects within the frame
4269 might be confused for camera motion by the motion vector search.
4271 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
4272 then the full frame is used. This allows later options to be set
4273 without specifying the bounding box for the motion vector search.
4275 Default - search the whole frame.
4279 Specify the maximum extent of movement in x and y directions in the
4280 range 0-64 pixels. Default 16.
4283 Specify how to generate pixels to fill blanks at the edge of the
4284 frame. Available values are:
4287 Fill zeroes at blank locations
4289 Original image at blank locations
4291 Extruded edge value at blank locations
4293 Mirrored edge at blank locations
4295 Default value is @samp{mirror}.
4298 Specify the blocksize to use for motion search. Range 4-128 pixels,
4302 Specify the contrast threshold for blocks. Only blocks with more than
4303 the specified contrast (difference between darkest and lightest
4304 pixels) will be considered. Range 1-255, default 125.
4307 Specify the search strategy. Available values are:
4310 Set exhaustive search
4312 Set less exhaustive search.
4314 Default value is @samp{exhaustive}.
4317 If set then a detailed log of the motion search is written to the
4321 If set to 1, specify using OpenCL capabilities, only available if
4322 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
4328 Apply an exact inverse of the telecine operation. It requires a predefined
4329 pattern specified using the pattern option which must be the same as that passed
4330 to the telecine filter.
4332 This filter accepts the following options:
4341 The default value is @code{top}.
4345 A string of numbers representing the pulldown pattern you wish to apply.
4346 The default value is @code{23}.
4349 A number representing position of the first frame with respect to the telecine
4350 pattern. This is to be used if the stream is cut. The default value is @code{0}.
4355 Apply dilation effect to the video.
4357 This filter replaces the pixel by the local(3x3) maximum.
4359 It accepts the following options:
4366 Allows to limit the maximum change for each plane, default is 65535.
4367 If 0, plane will remain unchanged.
4370 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
4373 Flags to local 3x3 coordinates maps like this:
4382 Draw a colored box on the input image.
4384 It accepts the following parameters:
4389 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
4393 The expressions which specify the width and height of the box; if 0 they are interpreted as
4394 the input width and height. It defaults to 0.
4397 Specify the color of the box to write. For the general syntax of this option,
4398 check the "Color" section in the ffmpeg-utils manual. If the special
4399 value @code{invert} is used, the box edge color is the same as the
4400 video with inverted luma.
4403 The expression which sets the thickness of the box edge. Default value is @code{3}.
4405 See below for the list of accepted constants.
4408 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
4409 following constants:
4413 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
4417 horizontal and vertical chroma subsample values. For example for the
4418 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4422 The input width and height.
4425 The input sample aspect ratio.
4429 The x and y offset coordinates where the box is drawn.
4433 The width and height of the drawn box.
4436 The thickness of the drawn box.
4438 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
4439 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
4443 @subsection Examples
4447 Draw a black box around the edge of the input image:
4453 Draw a box with color red and an opacity of 50%:
4455 drawbox=10:20:200:60:red@@0.5
4458 The previous example can be specified as:
4460 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
4464 Fill the box with pink color:
4466 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
4470 Draw a 2-pixel red 2.40:1 mask:
4472 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
4476 @section drawgraph, adrawgraph
4478 Draw a graph using input video or audio metadata.
4480 It accepts the following parameters:
4484 Set 1st frame metadata key from which metadata values will be used to draw a graph.
4487 Set 1st foreground color expression.
4490 Set 2nd frame metadata key from which metadata values will be used to draw a graph.
4493 Set 2nd foreground color expression.
4496 Set 3rd frame metadata key from which metadata values will be used to draw a graph.
4499 Set 3rd foreground color expression.
4502 Set 4th frame metadata key from which metadata values will be used to draw a graph.
4505 Set 4th foreground color expression.
4508 Set minimal value of metadata value.
4511 Set maximal value of metadata value.
4514 Set graph background color. Default is white.
4519 Available values for mode is:
4526 Default is @code{line}.
4531 Available values for slide is:
4534 Draw new frame when right border is reached.
4537 Replace old columns with new ones.
4540 Scroll from right to left.
4543 Scroll from left to right.
4546 Default is @code{frame}.
4549 Set size of graph video. For the syntax of this option, check the
4550 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
4551 The default value is @code{900x256}.
4553 The foreground color expressions can use the following variables:
4556 Minimal value of metadata value.
4559 Maximal value of metadata value.
4562 Current metadata key value.
4565 The color is defined as 0xAABBGGRR.
4568 Example using metadata from @ref{signalstats} filter:
4570 signalstats,drawgraph=lavfi.signalstats.YAVG:min=0:max=255
4573 Example using metadata from @ref{ebur128} filter:
4575 ebur128=metadata=1,adrawgraph=lavfi.r128.M:min=-120:max=5
4580 Draw a grid on the input image.
4582 It accepts the following parameters:
4587 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
4591 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
4592 input width and height, respectively, minus @code{thickness}, so image gets
4593 framed. Default to 0.
4596 Specify the color of the grid. For the general syntax of this option,
4597 check the "Color" section in the ffmpeg-utils manual. If the special
4598 value @code{invert} is used, the grid color is the same as the
4599 video with inverted luma.
4602 The expression which sets the thickness of the grid line. Default value is @code{1}.
4604 See below for the list of accepted constants.
4607 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
4608 following constants:
4612 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
4616 horizontal and vertical chroma subsample values. For example for the
4617 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4621 The input grid cell width and height.
4624 The input sample aspect ratio.
4628 The x and y coordinates of some point of grid intersection (meant to configure offset).
4632 The width and height of the drawn cell.
4635 The thickness of the drawn cell.
4637 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
4638 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
4642 @subsection Examples
4646 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
4648 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
4652 Draw a white 3x3 grid with an opacity of 50%:
4654 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
4661 Draw a text string or text from a specified file on top of a video, using the
4662 libfreetype library.
4664 To enable compilation of this filter, you need to configure FFmpeg with
4665 @code{--enable-libfreetype}.
4666 To enable default font fallback and the @var{font} option you need to
4667 configure FFmpeg with @code{--enable-libfontconfig}.
4668 To enable the @var{text_shaping} option, you need to configure FFmpeg with
4669 @code{--enable-libfribidi}.
4673 It accepts the following parameters:
4678 Used to draw a box around text using the background color.
4679 The value must be either 1 (enable) or 0 (disable).
4680 The default value of @var{box} is 0.
4683 Set the width of the border to be drawn around the box using @var{boxcolor}.
4684 The default value of @var{boxborderw} is 0.
4687 The color to be used for drawing box around text. For the syntax of this
4688 option, check the "Color" section in the ffmpeg-utils manual.
4690 The default value of @var{boxcolor} is "white".
4693 Set the width of the border to be drawn around the text using @var{bordercolor}.
4694 The default value of @var{borderw} is 0.
4697 Set the color to be used for drawing border around text. For the syntax of this
4698 option, check the "Color" section in the ffmpeg-utils manual.
4700 The default value of @var{bordercolor} is "black".
4703 Select how the @var{text} is expanded. Can be either @code{none},
4704 @code{strftime} (deprecated) or
4705 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
4709 If true, check and fix text coords to avoid clipping.
4712 The color to be used for drawing fonts. For the syntax of this option, check
4713 the "Color" section in the ffmpeg-utils manual.
4715 The default value of @var{fontcolor} is "black".
4717 @item fontcolor_expr
4718 String which is expanded the same way as @var{text} to obtain dynamic
4719 @var{fontcolor} value. By default this option has empty value and is not
4720 processed. When this option is set, it overrides @var{fontcolor} option.
4723 The font family to be used for drawing text. By default Sans.
4726 The font file to be used for drawing text. The path must be included.
4727 This parameter is mandatory if the fontconfig support is disabled.
4730 This option does not exist, please see the timeline system
4733 Draw the text applying alpha blending. The value can
4734 be either a number between 0.0 and 1.0
4735 The expression accepts the same variables @var{x, y} do.
4736 The default value is 1.
4737 Please see fontcolor_expr
4740 The font size to be used for drawing text.
4741 The default value of @var{fontsize} is 16.
4744 If set to 1, attempt to shape the text (for example, reverse the order of
4745 right-to-left text and join Arabic characters) before drawing it.
4746 Otherwise, just draw the text exactly as given.
4747 By default 1 (if supported).
4750 The flags to be used for loading the fonts.
4752 The flags map the corresponding flags supported by libfreetype, and are
4753 a combination of the following values:
4760 @item vertical_layout
4761 @item force_autohint
4764 @item ignore_global_advance_width
4766 @item ignore_transform
4772 Default value is "default".
4774 For more information consult the documentation for the FT_LOAD_*
4778 The color to be used for drawing a shadow behind the drawn text. For the
4779 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
4781 The default value of @var{shadowcolor} is "black".
4785 The x and y offsets for the text shadow position with respect to the
4786 position of the text. They can be either positive or negative
4787 values. The default value for both is "0".
4790 The starting frame number for the n/frame_num variable. The default value
4794 The size in number of spaces to use for rendering the tab.
4798 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
4799 format. It can be used with or without text parameter. @var{timecode_rate}
4800 option must be specified.
4802 @item timecode_rate, rate, r
4803 Set the timecode frame rate (timecode only).
4806 The text string to be drawn. The text must be a sequence of UTF-8
4808 This parameter is mandatory if no file is specified with the parameter
4812 A text file containing text to be drawn. The text must be a sequence
4813 of UTF-8 encoded characters.
4815 This parameter is mandatory if no text string is specified with the
4816 parameter @var{text}.
4818 If both @var{text} and @var{textfile} are specified, an error is thrown.
4821 If set to 1, the @var{textfile} will be reloaded before each frame.
4822 Be sure to update it atomically, or it may be read partially, or even fail.
4826 The expressions which specify the offsets where text will be drawn
4827 within the video frame. They are relative to the top/left border of the
4830 The default value of @var{x} and @var{y} is "0".
4832 See below for the list of accepted constants and functions.
4835 The parameters for @var{x} and @var{y} are expressions containing the
4836 following constants and functions:
4840 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
4844 horizontal and vertical chroma subsample values. For example for the
4845 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
4848 the height of each text line
4856 @item max_glyph_a, ascent
4857 the maximum distance from the baseline to the highest/upper grid
4858 coordinate used to place a glyph outline point, for all the rendered
4860 It is a positive value, due to the grid's orientation with the Y axis
4863 @item max_glyph_d, descent
4864 the maximum distance from the baseline to the lowest grid coordinate
4865 used to place a glyph outline point, for all the rendered glyphs.
4866 This is a negative value, due to the grid's orientation, with the Y axis
4870 maximum glyph height, that is the maximum height for all the glyphs
4871 contained in the rendered text, it is equivalent to @var{ascent} -
4875 maximum glyph width, that is the maximum width for all the glyphs
4876 contained in the rendered text
4879 the number of input frame, starting from 0
4881 @item rand(min, max)
4882 return a random number included between @var{min} and @var{max}
4885 The input sample aspect ratio.
4888 timestamp expressed in seconds, NAN if the input timestamp is unknown
4891 the height of the rendered text
4894 the width of the rendered text
4898 the x and y offset coordinates where the text is drawn.
4900 These parameters allow the @var{x} and @var{y} expressions to refer
4901 each other, so you can for example specify @code{y=x/dar}.
4904 @anchor{drawtext_expansion}
4905 @subsection Text expansion
4907 If @option{expansion} is set to @code{strftime},
4908 the filter recognizes strftime() sequences in the provided text and
4909 expands them accordingly. Check the documentation of strftime(). This
4910 feature is deprecated.
4912 If @option{expansion} is set to @code{none}, the text is printed verbatim.
4914 If @option{expansion} is set to @code{normal} (which is the default),
4915 the following expansion mechanism is used.
4917 The backslash character @samp{\}, followed by any character, always expands to
4918 the second character.
4920 Sequence of the form @code{%@{...@}} are expanded. The text between the
4921 braces is a function name, possibly followed by arguments separated by ':'.
4922 If the arguments contain special characters or delimiters (':' or '@}'),
4923 they should be escaped.
4925 Note that they probably must also be escaped as the value for the
4926 @option{text} option in the filter argument string and as the filter
4927 argument in the filtergraph description, and possibly also for the shell,
4928 that makes up to four levels of escaping; using a text file avoids these
4931 The following functions are available:
4936 The expression evaluation result.
4938 It must take one argument specifying the expression to be evaluated,
4939 which accepts the same constants and functions as the @var{x} and
4940 @var{y} values. Note that not all constants should be used, for
4941 example the text size is not known when evaluating the expression, so
4942 the constants @var{text_w} and @var{text_h} will have an undefined
4945 @item expr_int_format, eif
4946 Evaluate the expression's value and output as formatted integer.
4948 The first argument is the expression to be evaluated, just as for the @var{expr} function.
4949 The second argument specifies the output format. Allowed values are @samp{x},
4950 @samp{X}, @samp{d} and @samp{u}. They are treated exactly as in the
4951 @code{printf} function.
4952 The third parameter is optional and sets the number of positions taken by the output.
4953 It can be used to add padding with zeros from the left.
4956 The time at which the filter is running, expressed in UTC.
4957 It can accept an argument: a strftime() format string.
4960 The time at which the filter is running, expressed in the local time zone.
4961 It can accept an argument: a strftime() format string.
4964 Frame metadata. It must take one argument specifying metadata key.
4967 The frame number, starting from 0.
4970 A 1 character description of the current picture type.
4973 The timestamp of the current frame.
4974 It can take up to two arguments.
4976 The first argument is the format of the timestamp; it defaults to @code{flt}
4977 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
4978 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
4980 The second argument is an offset added to the timestamp.
4984 @subsection Examples
4988 Draw "Test Text" with font FreeSerif, using the default values for the
4989 optional parameters.
4992 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
4996 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
4997 and y=50 (counting from the top-left corner of the screen), text is
4998 yellow with a red box around it. Both the text and the box have an
5002 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
5003 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
5006 Note that the double quotes are not necessary if spaces are not used
5007 within the parameter list.
5010 Show the text at the center of the video frame:
5012 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
5016 Show a text line sliding from right to left in the last row of the video
5017 frame. The file @file{LONG_LINE} is assumed to contain a single line
5020 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
5024 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
5026 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
5030 Draw a single green letter "g", at the center of the input video.
5031 The glyph baseline is placed at half screen height.
5033 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
5037 Show text for 1 second every 3 seconds:
5039 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
5043 Use fontconfig to set the font. Note that the colons need to be escaped.
5045 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
5049 Print the date of a real-time encoding (see strftime(3)):
5051 drawtext='fontfile=FreeSans.ttf:text=%@{localtime\:%a %b %d %Y@}'
5055 Show text fading in and out (appearing/disappearing):
5058 DS=1.0 # display start
5059 DE=10.0 # display end
5060 FID=1.5 # fade in duration
5061 FOD=5 # fade out duration
5062 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 @}"
5067 For more information about libfreetype, check:
5068 @url{http://www.freetype.org/}.
5070 For more information about fontconfig, check:
5071 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
5073 For more information about libfribidi, check:
5074 @url{http://fribidi.org/}.
5078 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
5080 The filter accepts the following options:
5085 Set low and high threshold values used by the Canny thresholding
5088 The high threshold selects the "strong" edge pixels, which are then
5089 connected through 8-connectivity with the "weak" edge pixels selected
5090 by the low threshold.
5092 @var{low} and @var{high} threshold values must be chosen in the range
5093 [0,1], and @var{low} should be lesser or equal to @var{high}.
5095 Default value for @var{low} is @code{20/255}, and default value for @var{high}
5099 Define the drawing mode.
5103 Draw white/gray wires on black background.
5106 Mix the colors to create a paint/cartoon effect.
5109 Default value is @var{wires}.
5112 @subsection Examples
5116 Standard edge detection with custom values for the hysteresis thresholding:
5118 edgedetect=low=0.1:high=0.4
5122 Painting effect without thresholding:
5124 edgedetect=mode=colormix:high=0
5129 Set brightness, contrast, saturation and approximate gamma adjustment.
5131 The filter accepts the following options:
5135 Set the contrast expression. The value must be a float value in range
5136 @code{-2.0} to @code{2.0}. The default value is "0".
5139 Set the brightness expression. The value must be a float value in
5140 range @code{-1.0} to @code{1.0}. The default value is "0".
5143 Set the saturation expression. The value must be a float in
5144 range @code{0.0} to @code{3.0}. The default value is "1".
5147 Set the gamma expression. The value must be a float in range
5148 @code{0.1} to @code{10.0}. The default value is "1".
5151 Set the gamma expression for red. The value must be a float in
5152 range @code{0.1} to @code{10.0}. The default value is "1".
5155 Set the gamma expression for green. The value must be a float in range
5156 @code{0.1} to @code{10.0}. The default value is "1".
5159 Set the gamma expression for blue. The value must be a float in range
5160 @code{0.1} to @code{10.0}. The default value is "1".
5163 Set the gamma weight expression. It can be used to reduce the effect
5164 of a high gamma value on bright image areas, e.g. keep them from
5165 getting overamplified and just plain white. The value must be a float
5166 in range @code{0.0} to @code{1.0}. A value of @code{0.0} turns the
5167 gamma correction all the way down while @code{1.0} leaves it at its
5168 full strength. Default is "1".
5171 Set when the expressions for brightness, contrast, saturation and
5172 gamma expressions are evaluated.
5174 It accepts the following values:
5177 only evaluate expressions once during the filter initialization or
5178 when a command is processed
5181 evaluate expressions for each incoming frame
5184 Default value is @samp{init}.
5187 The expressions accept the following parameters:
5190 frame count of the input frame starting from 0
5193 byte position of the corresponding packet in the input file, NAN if
5197 frame rate of the input video, NAN if the input frame rate is unknown
5200 timestamp expressed in seconds, NAN if the input timestamp is unknown
5203 @subsection Commands
5204 The filter supports the following commands:
5208 Set the contrast expression.
5211 Set the brightness expression.
5214 Set the saturation expression.
5217 Set the gamma expression.
5220 Set the gamma_r expression.
5223 Set gamma_g expression.
5226 Set gamma_b expression.
5229 Set gamma_weight expression.
5231 The command accepts the same syntax of the corresponding option.
5233 If the specified expression is not valid, it is kept at its current
5240 Apply erosion effect to the video.
5242 This filter replaces the pixel by the local(3x3) minimum.
5244 It accepts the following options:
5251 Allows to limit the maximum change for each plane, default is 65535.
5252 If 0, plane will remain unchanged.
5255 Flag which specifies the pixel to refer to. Default is 255 i.e. all eight
5258 Flags to local 3x3 coordinates maps like this:
5265 @section extractplanes
5267 Extract color channel components from input video stream into
5268 separate grayscale video streams.
5270 The filter accepts the following option:
5274 Set plane(s) to extract.
5276 Available values for planes are:
5287 Choosing planes not available in the input will result in an error.
5288 That means you cannot select @code{r}, @code{g}, @code{b} planes
5289 with @code{y}, @code{u}, @code{v} planes at same time.
5292 @subsection Examples
5296 Extract luma, u and v color channel component from input video frame
5297 into 3 grayscale outputs:
5299 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
5305 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
5307 For each input image, the filter will compute the optimal mapping from
5308 the input to the output given the codebook length, that is the number
5309 of distinct output colors.
5311 This filter accepts the following options.
5314 @item codebook_length, l
5315 Set codebook length. The value must be a positive integer, and
5316 represents the number of distinct output colors. Default value is 256.
5319 Set the maximum number of iterations to apply for computing the optimal
5320 mapping. The higher the value the better the result and the higher the
5321 computation time. Default value is 1.
5324 Set a random seed, must be an integer included between 0 and
5325 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
5326 will try to use a good random seed on a best effort basis.
5329 Set pal8 output pixel format. This option does not work with codebook
5330 length greater than 256.
5335 Apply a fade-in/out effect to the input video.
5337 It accepts the following parameters:
5341 The effect type can be either "in" for a fade-in, or "out" for a fade-out
5343 Default is @code{in}.
5345 @item start_frame, s
5346 Specify the number of the frame to start applying the fade
5347 effect at. Default is 0.
5350 The number of frames that the fade effect lasts. At the end of the
5351 fade-in effect, the output video will have the same intensity as the input video.
5352 At the end of the fade-out transition, the output video will be filled with the
5353 selected @option{color}.
5357 If set to 1, fade only alpha channel, if one exists on the input.
5360 @item start_time, st
5361 Specify the timestamp (in seconds) of the frame to start to apply the fade
5362 effect. If both start_frame and start_time are specified, the fade will start at
5363 whichever comes last. Default is 0.
5366 The number of seconds for which the fade effect has to last. At the end of the
5367 fade-in effect the output video will have the same intensity as the input video,
5368 at the end of the fade-out transition the output video will be filled with the
5369 selected @option{color}.
5370 If both duration and nb_frames are specified, duration is used. Default is 0
5371 (nb_frames is used by default).
5374 Specify the color of the fade. Default is "black".
5377 @subsection Examples
5381 Fade in the first 30 frames of video:
5386 The command above is equivalent to:
5392 Fade out the last 45 frames of a 200-frame video:
5395 fade=type=out:start_frame=155:nb_frames=45
5399 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
5401 fade=in:0:25, fade=out:975:25
5405 Make the first 5 frames yellow, then fade in from frame 5-24:
5407 fade=in:5:20:color=yellow
5411 Fade in alpha over first 25 frames of video:
5413 fade=in:0:25:alpha=1
5417 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
5419 fade=t=in:st=5.5:d=0.5
5425 Apply arbitrary expressions to samples in frequency domain
5429 Adjust the dc value (gain) of the luma plane of the image. The filter
5430 accepts an integer value in range @code{0} to @code{1000}. The default
5431 value is set to @code{0}.
5434 Adjust the dc value (gain) of the 1st chroma plane of the image. The
5435 filter accepts an integer value in range @code{0} to @code{1000}. The
5436 default value is set to @code{0}.
5439 Adjust the dc value (gain) of the 2nd chroma plane of the image. The
5440 filter accepts an integer value in range @code{0} to @code{1000}. The
5441 default value is set to @code{0}.
5444 Set the frequency domain weight expression for the luma plane.
5447 Set the frequency domain weight expression for the 1st chroma plane.
5450 Set the frequency domain weight expression for the 2nd chroma plane.
5452 The filter accepts the following variables:
5455 The coordinates of the current sample.
5459 The width and height of the image.
5462 @subsection Examples
5468 fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'
5474 fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'
5480 fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'
5487 Extract a single field from an interlaced image using stride
5488 arithmetic to avoid wasting CPU time. The output frames are marked as
5491 The filter accepts the following options:
5495 Specify whether to extract the top (if the value is @code{0} or
5496 @code{top}) or the bottom field (if the value is @code{1} or
5502 Field matching filter for inverse telecine. It is meant to reconstruct the
5503 progressive frames from a telecined stream. The filter does not drop duplicated
5504 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
5505 followed by a decimation filter such as @ref{decimate} in the filtergraph.
5507 The separation of the field matching and the decimation is notably motivated by
5508 the possibility of inserting a de-interlacing filter fallback between the two.
5509 If the source has mixed telecined and real interlaced content,
5510 @code{fieldmatch} will not be able to match fields for the interlaced parts.
5511 But these remaining combed frames will be marked as interlaced, and thus can be
5512 de-interlaced by a later filter such as @ref{yadif} before decimation.
5514 In addition to the various configuration options, @code{fieldmatch} can take an
5515 optional second stream, activated through the @option{ppsrc} option. If
5516 enabled, the frames reconstruction will be based on the fields and frames from
5517 this second stream. This allows the first input to be pre-processed in order to
5518 help the various algorithms of the filter, while keeping the output lossless
5519 (assuming the fields are matched properly). Typically, a field-aware denoiser,
5520 or brightness/contrast adjustments can help.
5522 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
5523 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
5524 which @code{fieldmatch} is based on. While the semantic and usage are very
5525 close, some behaviour and options names can differ.
5527 The @ref{decimate} filter currently only works for constant frame rate input.
5528 If your input has mixed telecined (30fps) and progressive content with a lower
5529 framerate like 24fps use the following filterchain to produce the necessary cfr
5530 stream: @code{dejudder,fps=30000/1001,fieldmatch,decimate}.
5532 The filter accepts the following options:
5536 Specify the assumed field order of the input stream. Available values are:
5540 Auto detect parity (use FFmpeg's internal parity value).
5542 Assume bottom field first.
5544 Assume top field first.
5547 Note that it is sometimes recommended not to trust the parity announced by the
5550 Default value is @var{auto}.
5553 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
5554 sense that it won't risk creating jerkiness due to duplicate frames when
5555 possible, but if there are bad edits or blended fields it will end up
5556 outputting combed frames when a good match might actually exist. On the other
5557 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
5558 but will almost always find a good frame if there is one. The other values are
5559 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
5560 jerkiness and creating duplicate frames versus finding good matches in sections
5561 with bad edits, orphaned fields, blended fields, etc.
5563 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
5565 Available values are:
5569 2-way matching (p/c)
5571 2-way matching, and trying 3rd match if still combed (p/c + n)
5573 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
5575 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
5576 still combed (p/c + n + u/b)
5578 3-way matching (p/c/n)
5580 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
5581 detected as combed (p/c/n + u/b)
5584 The parenthesis at the end indicate the matches that would be used for that
5585 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
5588 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
5591 Default value is @var{pc_n}.
5594 Mark the main input stream as a pre-processed input, and enable the secondary
5595 input stream as the clean source to pick the fields from. See the filter
5596 introduction for more details. It is similar to the @option{clip2} feature from
5599 Default value is @code{0} (disabled).
5602 Set the field to match from. It is recommended to set this to the same value as
5603 @option{order} unless you experience matching failures with that setting. In
5604 certain circumstances changing the field that is used to match from can have a
5605 large impact on matching performance. Available values are:
5609 Automatic (same value as @option{order}).
5611 Match from the bottom field.
5613 Match from the top field.
5616 Default value is @var{auto}.
5619 Set whether or not chroma is included during the match comparisons. In most
5620 cases it is recommended to leave this enabled. You should set this to @code{0}
5621 only if your clip has bad chroma problems such as heavy rainbowing or other
5622 artifacts. Setting this to @code{0} could also be used to speed things up at
5623 the cost of some accuracy.
5625 Default value is @code{1}.
5629 These define an exclusion band which excludes the lines between @option{y0} and
5630 @option{y1} from being included in the field matching decision. An exclusion
5631 band can be used to ignore subtitles, a logo, or other things that may
5632 interfere with the matching. @option{y0} sets the starting scan line and
5633 @option{y1} sets the ending line; all lines in between @option{y0} and
5634 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
5635 @option{y0} and @option{y1} to the same value will disable the feature.
5636 @option{y0} and @option{y1} defaults to @code{0}.
5639 Set the scene change detection threshold as a percentage of maximum change on
5640 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
5641 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
5642 @option{scthresh} is @code{[0.0, 100.0]}.
5644 Default value is @code{12.0}.
5647 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
5648 account the combed scores of matches when deciding what match to use as the
5649 final match. Available values are:
5653 No final matching based on combed scores.
5655 Combed scores are only used when a scene change is detected.
5657 Use combed scores all the time.
5660 Default is @var{sc}.
5663 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
5664 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
5665 Available values are:
5669 No forced calculation.
5671 Force p/c/n calculations.
5673 Force p/c/n/u/b calculations.
5676 Default value is @var{none}.
5679 This is the area combing threshold used for combed frame detection. This
5680 essentially controls how "strong" or "visible" combing must be to be detected.
5681 Larger values mean combing must be more visible and smaller values mean combing
5682 can be less visible or strong and still be detected. Valid settings are from
5683 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
5684 be detected as combed). This is basically a pixel difference value. A good
5685 range is @code{[8, 12]}.
5687 Default value is @code{9}.
5690 Sets whether or not chroma is considered in the combed frame decision. Only
5691 disable this if your source has chroma problems (rainbowing, etc.) that are
5692 causing problems for the combed frame detection with chroma enabled. Actually,
5693 using @option{chroma}=@var{0} is usually more reliable, except for the case
5694 where there is chroma only combing in the source.
5696 Default value is @code{0}.
5700 Respectively set the x-axis and y-axis size of the window used during combed
5701 frame detection. This has to do with the size of the area in which
5702 @option{combpel} pixels are required to be detected as combed for a frame to be
5703 declared combed. See the @option{combpel} parameter description for more info.
5704 Possible values are any number that is a power of 2 starting at 4 and going up
5707 Default value is @code{16}.
5710 The number of combed pixels inside any of the @option{blocky} by
5711 @option{blockx} size blocks on the frame for the frame to be detected as
5712 combed. While @option{cthresh} controls how "visible" the combing must be, this
5713 setting controls "how much" combing there must be in any localized area (a
5714 window defined by the @option{blockx} and @option{blocky} settings) on the
5715 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
5716 which point no frames will ever be detected as combed). This setting is known
5717 as @option{MI} in TFM/VFM vocabulary.
5719 Default value is @code{80}.
5722 @anchor{p/c/n/u/b meaning}
5723 @subsection p/c/n/u/b meaning
5725 @subsubsection p/c/n
5727 We assume the following telecined stream:
5730 Top fields: 1 2 2 3 4
5731 Bottom fields: 1 2 3 4 4
5734 The numbers correspond to the progressive frame the fields relate to. Here, the
5735 first two frames are progressive, the 3rd and 4th are combed, and so on.
5737 When @code{fieldmatch} is configured to run a matching from bottom
5738 (@option{field}=@var{bottom}) this is how this input stream get transformed:
5743 B 1 2 3 4 4 <-- matching reference
5752 As a result of the field matching, we can see that some frames get duplicated.
5753 To perform a complete inverse telecine, you need to rely on a decimation filter
5754 after this operation. See for instance the @ref{decimate} filter.
5756 The same operation now matching from top fields (@option{field}=@var{top})
5761 T 1 2 2 3 4 <-- matching reference
5771 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
5772 basically, they refer to the frame and field of the opposite parity:
5775 @item @var{p} matches the field of the opposite parity in the previous frame
5776 @item @var{c} matches the field of the opposite parity in the current frame
5777 @item @var{n} matches the field of the opposite parity in the next frame
5782 The @var{u} and @var{b} matching are a bit special in the sense that they match
5783 from the opposite parity flag. In the following examples, we assume that we are
5784 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
5785 'x' is placed above and below each matched fields.
5787 With bottom matching (@option{field}=@var{bottom}):
5792 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
5793 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
5801 With top matching (@option{field}=@var{top}):
5806 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
5807 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
5815 @subsection Examples
5817 Simple IVTC of a top field first telecined stream:
5819 fieldmatch=order=tff:combmatch=none, decimate
5822 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
5824 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
5829 Transform the field order of the input video.
5831 It accepts the following parameters:
5836 The output field order. Valid values are @var{tff} for top field first or @var{bff}
5837 for bottom field first.
5840 The default value is @samp{tff}.
5842 The transformation is done by shifting the picture content up or down
5843 by one line, and filling the remaining line with appropriate picture content.
5844 This method is consistent with most broadcast field order converters.
5846 If the input video is not flagged as being interlaced, or it is already
5847 flagged as being of the required output field order, then this filter does
5848 not alter the incoming video.
5850 It is very useful when converting to or from PAL DV material,
5851 which is bottom field first.
5855 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
5860 Buffer input images and send them when they are requested.
5862 It is mainly useful when auto-inserted by the libavfilter
5865 It does not take parameters.
5869 Find a rectangular object
5871 It accepts the following options:
5875 Filepath of the object image, needs to be in gray8.
5878 Detection threshold, default is 0.5.
5881 Number of mipmaps, default is 3.
5883 @item xmin, ymin, xmax, ymax
5884 Specifies the rectangle in which to search.
5887 @subsection Examples
5891 Generate a representative palette of a given video using @command{ffmpeg}:
5893 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
5899 Cover a rectangular object
5901 It accepts the following options:
5905 Filepath of the optional cover image, needs to be in yuv420.
5910 It accepts the following values:
5913 cover it by the supplied image
5915 cover it by interpolating the surrounding pixels
5918 Default value is @var{blur}.
5921 @subsection Examples
5925 Generate a representative palette of a given video using @command{ffmpeg}:
5927 ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv
5934 Convert the input video to one of the specified pixel formats.
5935 Libavfilter will try to pick one that is suitable as input to
5938 It accepts the following parameters:
5942 A '|'-separated list of pixel format names, such as
5943 "pix_fmts=yuv420p|monow|rgb24".
5947 @subsection Examples
5951 Convert the input video to the @var{yuv420p} format
5953 format=pix_fmts=yuv420p
5956 Convert the input video to any of the formats in the list
5958 format=pix_fmts=yuv420p|yuv444p|yuv410p
5965 Convert the video to specified constant frame rate by duplicating or dropping
5966 frames as necessary.
5968 It accepts the following parameters:
5972 The desired output frame rate. The default is @code{25}.
5977 Possible values are:
5980 zero round towards 0
5984 round towards -infinity
5986 round towards +infinity
5990 The default is @code{near}.
5993 Assume the first PTS should be the given value, in seconds. This allows for
5994 padding/trimming at the start of stream. By default, no assumption is made
5995 about the first frame's expected PTS, so no padding or trimming is done.
5996 For example, this could be set to 0 to pad the beginning with duplicates of
5997 the first frame if a video stream starts after the audio stream or to trim any
5998 frames with a negative PTS.
6002 Alternatively, the options can be specified as a flat string:
6003 @var{fps}[:@var{round}].
6005 See also the @ref{setpts} filter.
6007 @subsection Examples
6011 A typical usage in order to set the fps to 25:
6017 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
6019 fps=fps=film:round=near
6025 Pack two different video streams into a stereoscopic video, setting proper
6026 metadata on supported codecs. The two views should have the same size and
6027 framerate and processing will stop when the shorter video ends. Please note
6028 that you may conveniently adjust view properties with the @ref{scale} and
6031 It accepts the following parameters:
6035 The desired packing format. Supported values are:
6040 The views are next to each other (default).
6043 The views are on top of each other.
6046 The views are packed by line.
6049 The views are packed by column.
6052 The views are temporally interleaved.
6061 # Convert left and right views into a frame-sequential video
6062 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
6064 # Convert views into a side-by-side video with the same output resolution as the input
6065 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
6070 Change the frame rate by interpolating new video output frames from the source
6073 This filter is not designed to function correctly with interlaced media. If
6074 you wish to change the frame rate of interlaced media then you are required
6075 to deinterlace before this filter and re-interlace after this filter.
6077 A description of the accepted options follows.
6081 Specify the output frames per second. This option can also be specified
6082 as a value alone. The default is @code{50}.
6085 Specify the start of a range where the output frame will be created as a
6086 linear interpolation of two frames. The range is [@code{0}-@code{255}],
6087 the default is @code{15}.
6090 Specify the end of a range where the output frame will be created as a
6091 linear interpolation of two frames. The range is [@code{0}-@code{255}],
6092 the default is @code{240}.
6095 Specify the level at which a scene change is detected as a value between
6096 0 and 100 to indicate a new scene; a low value reflects a low
6097 probability for the current frame to introduce a new scene, while a higher
6098 value means the current frame is more likely to be one.
6099 The default is @code{7}.
6102 Specify flags influencing the filter process.
6104 Available value for @var{flags} is:
6107 @item scene_change_detect, scd
6108 Enable scene change detection using the value of the option @var{scene}.
6109 This flag is enabled by default.
6115 Select one frame every N-th frame.
6117 This filter accepts the following option:
6120 Select frame after every @code{step} frames.
6121 Allowed values are positive integers higher than 0. Default value is @code{1}.
6127 Apply a frei0r effect to the input video.
6129 To enable the compilation of this filter, you need to install the frei0r
6130 header and configure FFmpeg with @code{--enable-frei0r}.
6132 It accepts the following parameters:
6137 The name of the frei0r effect to load. If the environment variable
6138 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
6139 directories specified by the colon-separated list in @env{FREIOR_PATH}.
6140 Otherwise, the standard frei0r paths are searched, in this order:
6141 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
6142 @file{/usr/lib/frei0r-1/}.
6145 A '|'-separated list of parameters to pass to the frei0r effect.
6149 A frei0r effect parameter can be a boolean (its value is either
6150 "y" or "n"), a double, a color (specified as
6151 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
6152 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
6153 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
6154 @var{X} and @var{Y} are floating point numbers) and/or a string.
6156 The number and types of parameters depend on the loaded effect. If an
6157 effect parameter is not specified, the default value is set.
6159 @subsection Examples
6163 Apply the distort0r effect, setting the first two double parameters:
6165 frei0r=filter_name=distort0r:filter_params=0.5|0.01
6169 Apply the colordistance effect, taking a color as the first parameter:
6171 frei0r=colordistance:0.2/0.3/0.4
6172 frei0r=colordistance:violet
6173 frei0r=colordistance:0x112233
6177 Apply the perspective effect, specifying the top left and top right image
6180 frei0r=perspective:0.2/0.2|0.8/0.2
6184 For more information, see
6185 @url{http://frei0r.dyne.org}
6189 Apply fast and simple postprocessing. It is a faster version of @ref{spp}.
6191 It splits (I)DCT into horizontal/vertical passes. Unlike the simple post-
6192 processing filter, one of them is performed once per block, not per pixel.
6193 This allows for much higher speed.
6195 The filter accepts the following options:
6199 Set quality. This option defines the number of levels for averaging. It accepts
6200 an integer in the range 4-5. Default value is @code{4}.
6203 Force a constant quantization parameter. It accepts an integer in range 0-63.
6204 If not set, the filter will use the QP from the video stream (if available).
6207 Set filter strength. It accepts an integer in range -15 to 32. Lower values mean
6208 more details but also more artifacts, while higher values make the image smoother
6209 but also blurrier. Default value is @code{0} − PSNR optimal.
6212 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
6213 option may cause flicker since the B-Frames have often larger QP. Default is
6214 @code{0} (not enabled).
6220 The filter accepts the following options:
6224 Set the luminance expression.
6226 Set the chrominance blue expression.
6228 Set the chrominance red expression.
6230 Set the alpha expression.
6232 Set the red expression.
6234 Set the green expression.
6236 Set the blue expression.
6239 The colorspace is selected according to the specified options. If one
6240 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
6241 options is specified, the filter will automatically select a YCbCr
6242 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
6243 @option{blue_expr} options is specified, it will select an RGB
6246 If one of the chrominance expression is not defined, it falls back on the other
6247 one. If no alpha expression is specified it will evaluate to opaque value.
6248 If none of chrominance expressions are specified, they will evaluate
6249 to the luminance expression.
6251 The expressions can use the following variables and functions:
6255 The sequential number of the filtered frame, starting from @code{0}.
6259 The coordinates of the current sample.
6263 The width and height of the image.
6267 Width and height scale depending on the currently filtered plane. It is the
6268 ratio between the corresponding luma plane number of pixels and the current
6269 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
6270 @code{0.5,0.5} for chroma planes.
6273 Time of the current frame, expressed in seconds.
6276 Return the value of the pixel at location (@var{x},@var{y}) of the current
6280 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
6284 Return the value of the pixel at location (@var{x},@var{y}) of the
6285 blue-difference chroma plane. Return 0 if there is no such plane.
6288 Return the value of the pixel at location (@var{x},@var{y}) of the
6289 red-difference chroma plane. Return 0 if there is no such plane.
6294 Return the value of the pixel at location (@var{x},@var{y}) of the
6295 red/green/blue component. Return 0 if there is no such component.
6298 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
6299 plane. Return 0 if there is no such plane.
6302 For functions, if @var{x} and @var{y} are outside the area, the value will be
6303 automatically clipped to the closer edge.
6305 @subsection Examples
6309 Flip the image horizontally:
6315 Generate a bidimensional sine wave, with angle @code{PI/3} and a
6316 wavelength of 100 pixels:
6318 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
6322 Generate a fancy enigmatic moving light:
6324 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
6328 Generate a quick emboss effect:
6330 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
6334 Modify RGB components depending on pixel position:
6336 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
6340 Create a radial gradient that is the same size as the input (also see
6341 the @ref{vignette} filter):
6343 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
6347 Create a linear gradient to use as a mask for another filter, then
6348 compose with @ref{overlay}. In this example the video will gradually
6349 become more blurry from the top to the bottom of the y-axis as defined
6350 by the linear gradient:
6352 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
6358 Fix the banding artifacts that are sometimes introduced into nearly flat
6359 regions by truncation to 8bit color depth.
6360 Interpolate the gradients that should go where the bands are, and
6363 It is designed for playback only. Do not use it prior to
6364 lossy compression, because compression tends to lose the dither and
6365 bring back the bands.
6367 It accepts the following parameters:
6372 The maximum amount by which the filter will change any one pixel. This is also
6373 the threshold for detecting nearly flat regions. Acceptable values range from
6374 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
6378 The neighborhood to fit the gradient to. A larger radius makes for smoother
6379 gradients, but also prevents the filter from modifying the pixels near detailed
6380 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
6381 values will be clipped to the valid range.
6385 Alternatively, the options can be specified as a flat string:
6386 @var{strength}[:@var{radius}]
6388 @subsection Examples
6392 Apply the filter with a @code{3.5} strength and radius of @code{8}:
6398 Specify radius, omitting the strength (which will fall-back to the default
6409 Apply a Hald CLUT to a video stream.
6411 First input is the video stream to process, and second one is the Hald CLUT.
6412 The Hald CLUT input can be a simple picture or a complete video stream.
6414 The filter accepts the following options:
6418 Force termination when the shortest input terminates. Default is @code{0}.
6420 Continue applying the last CLUT after the end of the stream. A value of
6421 @code{0} disable the filter after the last frame of the CLUT is reached.
6422 Default is @code{1}.
6425 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
6426 filters share the same internals).
6428 More information about the Hald CLUT can be found on Eskil Steenberg's website
6429 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
6431 @subsection Workflow examples
6433 @subsubsection Hald CLUT video stream
6435 Generate an identity Hald CLUT stream altered with various effects:
6437 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
6440 Note: make sure you use a lossless codec.
6442 Then use it with @code{haldclut} to apply it on some random stream:
6444 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
6447 The Hald CLUT will be applied to the 10 first seconds (duration of
6448 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
6449 to the remaining frames of the @code{mandelbrot} stream.
6451 @subsubsection Hald CLUT with preview
6453 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
6454 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
6455 biggest possible square starting at the top left of the picture. The remaining
6456 padding pixels (bottom or right) will be ignored. This area can be used to add
6457 a preview of the Hald CLUT.
6459 Typically, the following generated Hald CLUT will be supported by the
6460 @code{haldclut} filter:
6463 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
6464 pad=iw+320 [padded_clut];
6465 smptebars=s=320x256, split [a][b];
6466 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
6467 [main][b] overlay=W-320" -frames:v 1 clut.png
6470 It contains the original and a preview of the effect of the CLUT: SMPTE color
6471 bars are displayed on the right-top, and below the same color bars processed by
6474 Then, the effect of this Hald CLUT can be visualized with:
6476 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
6481 Flip the input video horizontally.
6483 For example, to horizontally flip the input video with @command{ffmpeg}:
6485 ffmpeg -i in.avi -vf "hflip" out.avi
6489 This filter applies a global color histogram equalization on a
6492 It can be used to correct video that has a compressed range of pixel
6493 intensities. The filter redistributes the pixel intensities to
6494 equalize their distribution across the intensity range. It may be
6495 viewed as an "automatically adjusting contrast filter". This filter is
6496 useful only for correcting degraded or poorly captured source
6499 The filter accepts the following options:
6503 Determine the amount of equalization to be applied. As the strength
6504 is reduced, the distribution of pixel intensities more-and-more
6505 approaches that of the input frame. The value must be a float number
6506 in the range [0,1] and defaults to 0.200.
6509 Set the maximum intensity that can generated and scale the output
6510 values appropriately. The strength should be set as desired and then
6511 the intensity can be limited if needed to avoid washing-out. The value
6512 must be a float number in the range [0,1] and defaults to 0.210.
6515 Set the antibanding level. If enabled the filter will randomly vary
6516 the luminance of output pixels by a small amount to avoid banding of
6517 the histogram. Possible values are @code{none}, @code{weak} or
6518 @code{strong}. It defaults to @code{none}.
6523 Compute and draw a color distribution histogram for the input video.
6525 The computed histogram is a representation of the color component
6526 distribution in an image.
6528 The filter accepts the following options:
6534 It accepts the following values:
6537 Standard histogram that displays the color components distribution in an
6538 image. Displays color graph for each color component. Shows distribution of
6539 the Y, U, V, A or R, G, B components, depending on input format, in the
6540 current frame. Below each graph a color component scale meter is shown.
6543 Displays chroma values (U/V color placement) in a two dimensional
6544 graph (which is called a vectorscope). The brighter a pixel in the
6545 vectorscope, the more pixels of the input frame correspond to that pixel
6546 (i.e., more pixels have this chroma value). The V component is displayed on
6547 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
6548 side being V = 255. The U component is displayed on the vertical (Y) axis,
6549 with the top representing U = 0 and the bottom representing U = 255.
6551 The position of a white pixel in the graph corresponds to the chroma value of
6552 a pixel of the input clip. The graph can therefore be used to read the hue
6553 (color flavor) and the saturation (the dominance of the hue in the color). As
6554 the hue of a color changes, it moves around the square. At the center of the
6555 square the saturation is zero, which means that the corresponding pixel has no
6556 color. If the amount of a specific color is increased (while leaving the other
6557 colors unchanged) the saturation increases, and the indicator moves towards
6558 the edge of the square.
6561 Chroma values in vectorscope, similar as @code{color} but actual chroma values
6565 Per row/column color component graph. In row mode, the graph on the left side
6566 represents color component value 0 and the right side represents value = 255.
6567 In column mode, the top side represents color component value = 0 and bottom
6568 side represents value = 255.
6570 Default value is @code{levels}.
6573 Set height of level in @code{levels}. Default value is @code{200}.
6574 Allowed range is [50, 2048].
6577 Set height of color scale in @code{levels}. Default value is @code{12}.
6578 Allowed range is [0, 40].
6581 Set step for @code{waveform} mode. Smaller values are useful to find out how
6582 many values of the same luminance are distributed across input rows/columns.
6583 Default value is @code{10}. Allowed range is [1, 255].
6586 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
6587 Default is @code{row}.
6589 @item waveform_mirror
6590 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
6591 means mirrored. In mirrored mode, higher values will be represented on the left
6592 side for @code{row} mode and at the top for @code{column} mode. Default is
6593 @code{0} (unmirrored).
6596 Set display mode for @code{waveform} and @code{levels}.
6597 It accepts the following values:
6600 Display separate graph for the color components side by side in
6601 @code{row} waveform mode or one below the other in @code{column} waveform mode
6602 for @code{waveform} histogram mode. For @code{levels} histogram mode,
6603 per color component graphs are placed below each other.
6605 Using this display mode in @code{waveform} histogram mode makes it easy to
6606 spot color casts in the highlights and shadows of an image, by comparing the
6607 contours of the top and the bottom graphs of each waveform. Since whites,
6608 grays, and blacks are characterized by exactly equal amounts of red, green,
6609 and blue, neutral areas of the picture should display three waveforms of
6610 roughly equal width/height. If not, the correction is easy to perform by
6611 making level adjustments the three waveforms.
6614 Presents information identical to that in the @code{parade}, except
6615 that the graphs representing color components are superimposed directly
6618 This display mode in @code{waveform} histogram mode makes it easier to spot
6619 relative differences or similarities in overlapping areas of the color
6620 components that are supposed to be identical, such as neutral whites, grays,
6623 Default is @code{parade}.
6626 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
6627 Default is @code{linear}.
6630 Set what color components to display for mode @code{levels}.
6631 Default is @code{7}.
6634 @subsection Examples
6639 Calculate and draw histogram:
6641 ffplay -i input -vf histogram
6649 This is a high precision/quality 3d denoise filter. It aims to reduce
6650 image noise, producing smooth images and making still images really
6651 still. It should enhance compressibility.
6653 It accepts the following optional parameters:
6657 A non-negative floating point number which specifies spatial luma strength.
6660 @item chroma_spatial
6661 A non-negative floating point number which specifies spatial chroma strength.
6662 It defaults to 3.0*@var{luma_spatial}/4.0.
6665 A floating point number which specifies luma temporal strength. It defaults to
6666 6.0*@var{luma_spatial}/4.0.
6669 A floating point number which specifies chroma temporal strength. It defaults to
6670 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
6675 Apply a high-quality magnification filter designed for pixel art. This filter
6676 was originally created by Maxim Stepin.
6678 It accepts the following option:
6682 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
6683 @code{hq3x} and @code{4} for @code{hq4x}.
6684 Default is @code{3}.
6688 Stack input videos horizontally.
6690 All streams must be of same pixel format and of same height.
6692 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
6693 to create same output.
6695 The filter accept the following option:
6699 Set number of input streams. Default is 2.
6704 Modify the hue and/or the saturation of the input.
6706 It accepts the following parameters:
6710 Specify the hue angle as a number of degrees. It accepts an expression,
6711 and defaults to "0".
6714 Specify the saturation in the [-10,10] range. It accepts an expression and
6718 Specify the hue angle as a number of radians. It accepts an
6719 expression, and defaults to "0".
6722 Specify the brightness in the [-10,10] range. It accepts an expression and
6726 @option{h} and @option{H} are mutually exclusive, and can't be
6727 specified at the same time.
6729 The @option{b}, @option{h}, @option{H} and @option{s} option values are
6730 expressions containing the following constants:
6734 frame count of the input frame starting from 0
6737 presentation timestamp of the input frame expressed in time base units
6740 frame rate of the input video, NAN if the input frame rate is unknown
6743 timestamp expressed in seconds, NAN if the input timestamp is unknown
6746 time base of the input video
6749 @subsection Examples
6753 Set the hue to 90 degrees and the saturation to 1.0:
6759 Same command but expressing the hue in radians:
6765 Rotate hue and make the saturation swing between 0
6766 and 2 over a period of 1 second:
6768 hue="H=2*PI*t: s=sin(2*PI*t)+1"
6772 Apply a 3 seconds saturation fade-in effect starting at 0:
6777 The general fade-in expression can be written as:
6779 hue="s=min(0\, max((t-START)/DURATION\, 1))"
6783 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
6785 hue="s=max(0\, min(1\, (8-t)/3))"
6788 The general fade-out expression can be written as:
6790 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
6795 @subsection Commands
6797 This filter supports the following commands:
6803 Modify the hue and/or the saturation and/or brightness of the input video.
6804 The command accepts the same syntax of the corresponding option.
6806 If the specified expression is not valid, it is kept at its current
6812 Detect video interlacing type.
6814 This filter tries to detect if the input frames as interlaced, progressive,
6815 top or bottom field first. It will also try and detect fields that are
6816 repeated between adjacent frames (a sign of telecine).
6818 Single frame detection considers only immediately adjacent frames when classifying each frame.
6819 Multiple frame detection incorporates the classification history of previous frames.
6821 The filter will log these metadata values:
6824 @item single.current_frame
6825 Detected type of current frame using single-frame detection. One of:
6826 ``tff'' (top field first), ``bff'' (bottom field first),
6827 ``progressive'', or ``undetermined''
6830 Cumulative number of frames detected as top field first using single-frame detection.
6833 Cumulative number of frames detected as top field first using multiple-frame detection.
6836 Cumulative number of frames detected as bottom field first using single-frame detection.
6838 @item multiple.current_frame
6839 Detected type of current frame using multiple-frame detection. One of:
6840 ``tff'' (top field first), ``bff'' (bottom field first),
6841 ``progressive'', or ``undetermined''
6844 Cumulative number of frames detected as bottom field first using multiple-frame detection.
6846 @item single.progressive
6847 Cumulative number of frames detected as progressive using single-frame detection.
6849 @item multiple.progressive
6850 Cumulative number of frames detected as progressive using multiple-frame detection.
6852 @item single.undetermined
6853 Cumulative number of frames that could not be classified using single-frame detection.
6855 @item multiple.undetermined
6856 Cumulative number of frames that could not be classified using multiple-frame detection.
6858 @item repeated.current_frame
6859 Which field in the current frame is repeated from the last. One of ``neither'', ``top'', or ``bottom''.
6861 @item repeated.neither
6862 Cumulative number of frames with no repeated field.
6865 Cumulative number of frames with the top field repeated from the previous frame's top field.
6867 @item repeated.bottom
6868 Cumulative number of frames with the bottom field repeated from the previous frame's bottom field.
6871 The filter accepts the following options:
6875 Set interlacing threshold.
6877 Set progressive threshold.
6879 Threshold for repeated field detection.
6881 Number of frames after which a given frame's contribution to the
6882 statistics is halved (i.e., it contributes only 0.5 to it's
6883 classification). The default of 0 means that all frames seen are given
6884 full weight of 1.0 forever.
6885 @item analyze_interlaced_flag
6886 When this is not 0 then idet will use the specified number of frames to determine
6887 if the interlaced flag is accurate, it will not count undetermined frames.
6888 If the flag is found to be accurate it will be used without any further
6889 computations, if it is found to be inaccurate it will be cleared without any
6890 further computations. This allows inserting the idet filter as a low computational
6891 method to clean up the interlaced flag
6896 Deinterleave or interleave fields.
6898 This filter allows one to process interlaced images fields without
6899 deinterlacing them. Deinterleaving splits the input frame into 2
6900 fields (so called half pictures). Odd lines are moved to the top
6901 half of the output image, even lines to the bottom half.
6902 You can process (filter) them independently and then re-interleave them.
6904 The filter accepts the following options:
6908 @item chroma_mode, c
6910 Available values for @var{luma_mode}, @var{chroma_mode} and
6911 @var{alpha_mode} are:
6917 @item deinterleave, d
6918 Deinterleave fields, placing one above the other.
6921 Interleave fields. Reverse the effect of deinterleaving.
6923 Default value is @code{none}.
6926 @item chroma_swap, cs
6927 @item alpha_swap, as
6928 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
6933 Apply inflate effect to the video.
6935 This filter replaces the pixel by the local(3x3) average by taking into account
6936 only values higher than the pixel.
6938 It accepts the following options:
6945 Allows to limit the maximum change for each plane, default is 65535.
6946 If 0, plane will remain unchanged.
6951 Simple interlacing filter from progressive contents. This interleaves upper (or
6952 lower) lines from odd frames with lower (or upper) lines from even frames,
6953 halving the frame rate and preserving image height.
6956 Original Original New Frame
6957 Frame 'j' Frame 'j+1' (tff)
6958 ========== =========== ==================
6959 Line 0 --------------------> Frame 'j' Line 0
6960 Line 1 Line 1 ----> Frame 'j+1' Line 1
6961 Line 2 ---------------------> Frame 'j' Line 2
6962 Line 3 Line 3 ----> Frame 'j+1' Line 3
6964 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
6967 It accepts the following optional parameters:
6971 This determines whether the interlaced frame is taken from the even
6972 (tff - default) or odd (bff) lines of the progressive frame.
6975 Enable (default) or disable the vertical lowpass filter to avoid twitter
6976 interlacing and reduce moire patterns.
6981 Deinterlace input video by applying Donald Graft's adaptive kernel
6982 deinterling. Work on interlaced parts of a video to produce
6985 The description of the accepted parameters follows.
6989 Set the threshold which affects the filter's tolerance when
6990 determining if a pixel line must be processed. It must be an integer
6991 in the range [0,255] and defaults to 10. A value of 0 will result in
6992 applying the process on every pixels.
6995 Paint pixels exceeding the threshold value to white if set to 1.
6999 Set the fields order. Swap fields if set to 1, leave fields alone if
7003 Enable additional sharpening if set to 1. Default is 0.
7006 Enable twoway sharpening if set to 1. Default is 0.
7009 @subsection Examples
7013 Apply default values:
7015 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
7019 Enable additional sharpening:
7025 Paint processed pixels in white:
7031 @section lenscorrection
7033 Correct radial lens distortion
7035 This filter can be used to correct for radial distortion as can result from the use
7036 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
7037 one can use tools available for example as part of opencv or simply trial-and-error.
7038 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
7039 and extract the k1 and k2 coefficients from the resulting matrix.
7041 Note that effectively the same filter is available in the open-source tools Krita and
7042 Digikam from the KDE project.
7044 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
7045 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
7046 brightness distribution, so you may want to use both filters together in certain
7047 cases, though you will have to take care of ordering, i.e. whether vignetting should
7048 be applied before or after lens correction.
7052 The filter accepts the following options:
7056 Relative x-coordinate of the focal point of the image, and thereby the center of the
7057 distortion. This value has a range [0,1] and is expressed as fractions of the image
7060 Relative y-coordinate of the focal point of the image, and thereby the center of the
7061 distortion. This value has a range [0,1] and is expressed as fractions of the image
7064 Coefficient of the quadratic correction term. 0.5 means no correction.
7066 Coefficient of the double quadratic correction term. 0.5 means no correction.
7069 The formula that generates the correction is:
7071 @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)
7073 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
7074 distances from the focal point in the source and target images, respectively.
7079 Apply a 3D LUT to an input video.
7081 The filter accepts the following options:
7085 Set the 3D LUT file name.
7087 Currently supported formats:
7099 Select interpolation mode.
7101 Available values are:
7105 Use values from the nearest defined point.
7107 Interpolate values using the 8 points defining a cube.
7109 Interpolate values using a tetrahedron.
7113 @section lut, lutrgb, lutyuv
7115 Compute a look-up table for binding each pixel component input value
7116 to an output value, and apply it to the input video.
7118 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
7119 to an RGB input video.
7121 These filters accept the following parameters:
7124 set first pixel component expression
7126 set second pixel component expression
7128 set third pixel component expression
7130 set fourth pixel component expression, corresponds to the alpha component
7133 set red component expression
7135 set green component expression
7137 set blue component expression
7139 alpha component expression
7142 set Y/luminance component expression
7144 set U/Cb component expression
7146 set V/Cr component expression
7149 Each of them specifies the expression to use for computing the lookup table for
7150 the corresponding pixel component values.
7152 The exact component associated to each of the @var{c*} options depends on the
7155 The @var{lut} filter requires either YUV or RGB pixel formats in input,
7156 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
7158 The expressions can contain the following constants and functions:
7163 The input width and height.
7166 The input value for the pixel component.
7169 The input value, clipped to the @var{minval}-@var{maxval} range.
7172 The maximum value for the pixel component.
7175 The minimum value for the pixel component.
7178 The negated value for the pixel component value, clipped to the
7179 @var{minval}-@var{maxval} range; it corresponds to the expression
7180 "maxval-clipval+minval".
7183 The computed value in @var{val}, clipped to the
7184 @var{minval}-@var{maxval} range.
7186 @item gammaval(gamma)
7187 The computed gamma correction value of the pixel component value,
7188 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
7190 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
7194 All expressions default to "val".
7196 @subsection Examples
7202 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
7203 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
7206 The above is the same as:
7208 lutrgb="r=negval:g=negval:b=negval"
7209 lutyuv="y=negval:u=negval:v=negval"
7219 Remove chroma components, turning the video into a graytone image:
7221 lutyuv="u=128:v=128"
7225 Apply a luma burning effect:
7231 Remove green and blue components:
7237 Set a constant alpha channel value on input:
7239 format=rgba,lutrgb=a="maxval-minval/2"
7243 Correct luminance gamma by a factor of 0.5:
7245 lutyuv=y=gammaval(0.5)
7249 Discard least significant bits of luma:
7251 lutyuv=y='bitand(val, 128+64+32)'
7255 @section mergeplanes
7257 Merge color channel components from several video streams.
7259 The filter accepts up to 4 input streams, and merge selected input
7260 planes to the output video.
7262 This filter accepts the following options:
7265 Set input to output plane mapping. Default is @code{0}.
7267 The mappings is specified as a bitmap. It should be specified as a
7268 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
7269 mapping for the first plane of the output stream. 'A' sets the number of
7270 the input stream to use (from 0 to 3), and 'a' the plane number of the
7271 corresponding input to use (from 0 to 3). The rest of the mappings is
7272 similar, 'Bb' describes the mapping for the output stream second
7273 plane, 'Cc' describes the mapping for the output stream third plane and
7274 'Dd' describes the mapping for the output stream fourth plane.
7277 Set output pixel format. Default is @code{yuva444p}.
7280 @subsection Examples
7284 Merge three gray video streams of same width and height into single video stream:
7286 [a0][a1][a2]mergeplanes=0x001020:yuv444p
7290 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
7292 [a0][a1]mergeplanes=0x00010210:yuva444p
7296 Swap Y and A plane in yuva444p stream:
7298 format=yuva444p,mergeplanes=0x03010200:yuva444p
7302 Swap U and V plane in yuv420p stream:
7304 format=yuv420p,mergeplanes=0x000201:yuv420p
7308 Cast a rgb24 clip to yuv444p:
7310 format=rgb24,mergeplanes=0x000102:yuv444p
7316 Apply motion-compensation deinterlacing.
7318 It needs one field per frame as input and must thus be used together
7319 with yadif=1/3 or equivalent.
7321 This filter accepts the following options:
7324 Set the deinterlacing mode.
7326 It accepts one of the following values:
7331 use iterative motion estimation
7333 like @samp{slow}, but use multiple reference frames.
7335 Default value is @samp{fast}.
7338 Set the picture field parity assumed for the input video. It must be
7339 one of the following values:
7343 assume top field first
7345 assume bottom field first
7348 Default value is @samp{bff}.
7351 Set per-block quantization parameter (QP) used by the internal
7354 Higher values should result in a smoother motion vector field but less
7355 optimal individual vectors. Default value is 1.
7360 Drop frames that do not differ greatly from the previous frame in
7361 order to reduce frame rate.
7363 The main use of this filter is for very-low-bitrate encoding
7364 (e.g. streaming over dialup modem), but it could in theory be used for
7365 fixing movies that were inverse-telecined incorrectly.
7367 A description of the accepted options follows.
7371 Set the maximum number of consecutive frames which can be dropped (if
7372 positive), or the minimum interval between dropped frames (if
7373 negative). If the value is 0, the frame is dropped unregarding the
7374 number of previous sequentially dropped frames.
7381 Set the dropping threshold values.
7383 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
7384 represent actual pixel value differences, so a threshold of 64
7385 corresponds to 1 unit of difference for each pixel, or the same spread
7386 out differently over the block.
7388 A frame is a candidate for dropping if no 8x8 blocks differ by more
7389 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
7390 meaning the whole image) differ by more than a threshold of @option{lo}.
7392 Default value for @option{hi} is 64*12, default value for @option{lo} is
7393 64*5, and default value for @option{frac} is 0.33.
7401 It accepts an integer in input; if non-zero it negates the
7402 alpha component (if available). The default value in input is 0.
7406 Force libavfilter not to use any of the specified pixel formats for the
7407 input to the next filter.
7409 It accepts the following parameters:
7413 A '|'-separated list of pixel format names, such as
7414 apix_fmts=yuv420p|monow|rgb24".
7418 @subsection Examples
7422 Force libavfilter to use a format different from @var{yuv420p} for the
7423 input to the vflip filter:
7425 noformat=pix_fmts=yuv420p,vflip
7429 Convert the input video to any of the formats not contained in the list:
7431 noformat=yuv420p|yuv444p|yuv410p
7437 Add noise on video input frame.
7439 The filter accepts the following options:
7447 Set noise seed for specific pixel component or all pixel components in case
7448 of @var{all_seed}. Default value is @code{123457}.
7450 @item all_strength, alls
7451 @item c0_strength, c0s
7452 @item c1_strength, c1s
7453 @item c2_strength, c2s
7454 @item c3_strength, c3s
7455 Set noise strength for specific pixel component or all pixel components in case
7456 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
7458 @item all_flags, allf
7463 Set pixel component flags or set flags for all components if @var{all_flags}.
7464 Available values for component flags are:
7467 averaged temporal noise (smoother)
7469 mix random noise with a (semi)regular pattern
7471 temporal noise (noise pattern changes between frames)
7473 uniform noise (gaussian otherwise)
7477 @subsection Examples
7479 Add temporal and uniform noise to input video:
7481 noise=alls=20:allf=t+u
7486 Pass the video source unchanged to the output.
7490 Apply a video transform using libopencv.
7492 To enable this filter, install the libopencv library and headers and
7493 configure FFmpeg with @code{--enable-libopencv}.
7495 It accepts the following parameters:
7500 The name of the libopencv filter to apply.
7503 The parameters to pass to the libopencv filter. If not specified, the default
7508 Refer to the official libopencv documentation for more precise
7510 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
7512 Several libopencv filters are supported; see the following subsections.
7517 Dilate an image by using a specific structuring element.
7518 It corresponds to the libopencv function @code{cvDilate}.
7520 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
7522 @var{struct_el} represents a structuring element, and has the syntax:
7523 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
7525 @var{cols} and @var{rows} represent the number of columns and rows of
7526 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
7527 point, and @var{shape} the shape for the structuring element. @var{shape}
7528 must be "rect", "cross", "ellipse", or "custom".
7530 If the value for @var{shape} is "custom", it must be followed by a
7531 string of the form "=@var{filename}". The file with name
7532 @var{filename} is assumed to represent a binary image, with each
7533 printable character corresponding to a bright pixel. When a custom
7534 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
7535 or columns and rows of the read file are assumed instead.
7537 The default value for @var{struct_el} is "3x3+0x0/rect".
7539 @var{nb_iterations} specifies the number of times the transform is
7540 applied to the image, and defaults to 1.
7544 # Use the default values
7547 # Dilate using a structuring element with a 5x5 cross, iterating two times
7548 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
7550 # Read the shape from the file diamond.shape, iterating two times.
7551 # The file diamond.shape may contain a pattern of characters like this
7557 # The specified columns and rows are ignored
7558 # but the anchor point coordinates are not
7559 ocv=dilate:0x0+2x2/custom=diamond.shape|2
7564 Erode an image by using a specific structuring element.
7565 It corresponds to the libopencv function @code{cvErode}.
7567 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
7568 with the same syntax and semantics as the @ref{dilate} filter.
7572 Smooth the input video.
7574 The filter takes the following parameters:
7575 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
7577 @var{type} is the type of smooth filter to apply, and must be one of
7578 the following values: "blur", "blur_no_scale", "median", "gaussian",
7579 or "bilateral". The default value is "gaussian".
7581 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
7582 depend on the smooth type. @var{param1} and
7583 @var{param2} accept integer positive values or 0. @var{param3} and
7584 @var{param4} accept floating point values.
7586 The default value for @var{param1} is 3. The default value for the
7587 other parameters is 0.
7589 These parameters correspond to the parameters assigned to the
7590 libopencv function @code{cvSmooth}.
7595 Overlay one video on top of another.
7597 It takes two inputs and has one output. The first input is the "main"
7598 video on which the second input is overlaid.
7600 It accepts the following parameters:
7602 A description of the accepted options follows.
7607 Set the expression for the x and y coordinates of the overlaid video
7608 on the main video. Default value is "0" for both expressions. In case
7609 the expression is invalid, it is set to a huge value (meaning that the
7610 overlay will not be displayed within the output visible area).
7613 The action to take when EOF is encountered on the secondary input; it accepts
7614 one of the following values:
7618 Repeat the last frame (the default).
7622 Pass the main input through.
7626 Set when the expressions for @option{x}, and @option{y} are evaluated.
7628 It accepts the following values:
7631 only evaluate expressions once during the filter initialization or
7632 when a command is processed
7635 evaluate expressions for each incoming frame
7638 Default value is @samp{frame}.
7641 If set to 1, force the output to terminate when the shortest input
7642 terminates. Default value is 0.
7645 Set the format for the output video.
7647 It accepts the following values:
7662 Default value is @samp{yuv420}.
7664 @item rgb @emph{(deprecated)}
7665 If set to 1, force the filter to accept inputs in the RGB
7666 color space. Default value is 0. This option is deprecated, use
7667 @option{format} instead.
7670 If set to 1, force the filter to draw the last overlay frame over the
7671 main input until the end of the stream. A value of 0 disables this
7672 behavior. Default value is 1.
7675 The @option{x}, and @option{y} expressions can contain the following
7681 The main input width and height.
7685 The overlay input width and height.
7689 The computed values for @var{x} and @var{y}. They are evaluated for
7694 horizontal and vertical chroma subsample values of the output
7695 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
7699 the number of input frame, starting from 0
7702 the position in the file of the input frame, NAN if unknown
7705 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
7709 Note that the @var{n}, @var{pos}, @var{t} variables are available only
7710 when evaluation is done @emph{per frame}, and will evaluate to NAN
7711 when @option{eval} is set to @samp{init}.
7713 Be aware that frames are taken from each input video in timestamp
7714 order, hence, if their initial timestamps differ, it is a good idea
7715 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
7716 have them begin in the same zero timestamp, as the example for
7717 the @var{movie} filter does.
7719 You can chain together more overlays but you should test the
7720 efficiency of such approach.
7722 @subsection Commands
7724 This filter supports the following commands:
7728 Modify the x and y of the overlay input.
7729 The command accepts the same syntax of the corresponding option.
7731 If the specified expression is not valid, it is kept at its current
7735 @subsection Examples
7739 Draw the overlay at 10 pixels from the bottom right corner of the main
7742 overlay=main_w-overlay_w-10:main_h-overlay_h-10
7745 Using named options the example above becomes:
7747 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
7751 Insert a transparent PNG logo in the bottom left corner of the input,
7752 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
7754 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
7758 Insert 2 different transparent PNG logos (second logo on bottom
7759 right corner) using the @command{ffmpeg} tool:
7761 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
7765 Add a transparent color layer on top of the main video; @code{WxH}
7766 must specify the size of the main input to the overlay filter:
7768 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
7772 Play an original video and a filtered version (here with the deshake
7773 filter) side by side using the @command{ffplay} tool:
7775 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
7778 The above command is the same as:
7780 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
7784 Make a sliding overlay appearing from the left to the right top part of the
7785 screen starting since time 2:
7787 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
7791 Compose output by putting two input videos side to side:
7793 ffmpeg -i left.avi -i right.avi -filter_complex "
7794 nullsrc=size=200x100 [background];
7795 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
7796 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
7797 [background][left] overlay=shortest=1 [background+left];
7798 [background+left][right] overlay=shortest=1:x=100 [left+right]
7803 Mask 10-20 seconds of a video by applying the delogo filter to a section
7805 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
7806 -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]'
7811 Chain several overlays in cascade:
7813 nullsrc=s=200x200 [bg];
7814 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
7815 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
7816 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
7817 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
7818 [in3] null, [mid2] overlay=100:100 [out0]
7825 Apply Overcomplete Wavelet denoiser.
7827 The filter accepts the following options:
7833 Larger depth values will denoise lower frequency components more, but
7834 slow down filtering.
7836 Must be an int in the range 8-16, default is @code{8}.
7838 @item luma_strength, ls
7841 Must be a double value in the range 0-1000, default is @code{1.0}.
7843 @item chroma_strength, cs
7844 Set chroma strength.
7846 Must be a double value in the range 0-1000, default is @code{1.0}.
7852 Add paddings to the input image, and place the original input at the
7853 provided @var{x}, @var{y} coordinates.
7855 It accepts the following parameters:
7860 Specify an expression for the size of the output image with the
7861 paddings added. If the value for @var{width} or @var{height} is 0, the
7862 corresponding input size is used for the output.
7864 The @var{width} expression can reference the value set by the
7865 @var{height} expression, and vice versa.
7867 The default value of @var{width} and @var{height} is 0.
7871 Specify the offsets to place the input image at within the padded area,
7872 with respect to the top/left border of the output image.
7874 The @var{x} expression can reference the value set by the @var{y}
7875 expression, and vice versa.
7877 The default value of @var{x} and @var{y} is 0.
7880 Specify the color of the padded area. For the syntax of this option,
7881 check the "Color" section in the ffmpeg-utils manual.
7883 The default value of @var{color} is "black".
7886 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
7887 options are expressions containing the following constants:
7892 The input video width and height.
7896 These are the same as @var{in_w} and @var{in_h}.
7900 The output width and height (the size of the padded area), as
7901 specified by the @var{width} and @var{height} expressions.
7905 These are the same as @var{out_w} and @var{out_h}.
7909 The x and y offsets as specified by the @var{x} and @var{y}
7910 expressions, or NAN if not yet specified.
7913 same as @var{iw} / @var{ih}
7916 input sample aspect ratio
7919 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
7923 The horizontal and vertical chroma subsample values. For example for the
7924 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7927 @subsection Examples
7931 Add paddings with the color "violet" to the input video. The output video
7932 size is 640x480, and the top-left corner of the input video is placed at
7935 pad=640:480:0:40:violet
7938 The example above is equivalent to the following command:
7940 pad=width=640:height=480:x=0:y=40:color=violet
7944 Pad the input to get an output with dimensions increased by 3/2,
7945 and put the input video at the center of the padded area:
7947 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
7951 Pad the input to get a squared output with size equal to the maximum
7952 value between the input width and height, and put the input video at
7953 the center of the padded area:
7955 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
7959 Pad the input to get a final w/h ratio of 16:9:
7961 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
7965 In case of anamorphic video, in order to set the output display aspect
7966 correctly, it is necessary to use @var{sar} in the expression,
7967 according to the relation:
7969 (ih * X / ih) * sar = output_dar
7970 X = output_dar / sar
7973 Thus the previous example needs to be modified to:
7975 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
7979 Double the output size and put the input video in the bottom-right
7980 corner of the output padded area:
7982 pad="2*iw:2*ih:ow-iw:oh-ih"
7989 Generate one palette for a whole video stream.
7991 It accepts the following options:
7995 Set the maximum number of colors to quantize in the palette.
7996 Note: the palette will still contain 256 colors; the unused palette entries
7999 @item reserve_transparent
8000 Create a palette of 255 colors maximum and reserve the last one for
8001 transparency. Reserving the transparency color is useful for GIF optimization.
8002 If not set, the maximum of colors in the palette will be 256. You probably want
8003 to disable this option for a standalone image.
8007 Set statistics mode.
8009 It accepts the following values:
8012 Compute full frame histograms.
8014 Compute histograms only for the part that differs from previous frame. This
8015 might be relevant to give more importance to the moving part of your input if
8016 the background is static.
8019 Default value is @var{full}.
8022 The filter also exports the frame metadata @code{lavfi.color_quant_ratio}
8023 (@code{nb_color_in / nb_color_out}) which you can use to evaluate the degree of
8024 color quantization of the palette. This information is also visible at
8025 @var{info} logging level.
8027 @subsection Examples
8031 Generate a representative palette of a given video using @command{ffmpeg}:
8033 ffmpeg -i input.mkv -vf palettegen palette.png
8039 Use a palette to downsample an input video stream.
8041 The filter takes two inputs: one video stream and a palette. The palette must
8042 be a 256 pixels image.
8044 It accepts the following options:
8048 Select dithering mode. Available algorithms are:
8051 Ordered 8x8 bayer dithering (deterministic)
8053 Dithering as defined by Paul Heckbert in 1982 (simple error diffusion).
8054 Note: this dithering is sometimes considered "wrong" and is included as a
8056 @item floyd_steinberg
8057 Floyd and Steingberg dithering (error diffusion)
8059 Frankie Sierra dithering v2 (error diffusion)
8061 Frankie Sierra dithering v2 "Lite" (error diffusion)
8064 Default is @var{sierra2_4a}.
8067 When @var{bayer} dithering is selected, this option defines the scale of the
8068 pattern (how much the crosshatch pattern is visible). A low value means more
8069 visible pattern for less banding, and higher value means less visible pattern
8070 at the cost of more banding.
8072 The option must be an integer value in the range [0,5]. Default is @var{2}.
8075 If set, define the zone to process
8079 Only the changing rectangle will be reprocessed. This is similar to GIF
8080 cropping/offsetting compression mechanism. This option can be useful for speed
8081 if only a part of the image is changing, and has use cases such as limiting the
8082 scope of the error diffusal @option{dither} to the rectangle that bounds the
8083 moving scene (it leads to more deterministic output if the scene doesn't change
8084 much, and as a result less moving noise and better GIF compression).
8087 Default is @var{none}.
8090 @subsection Examples
8094 Use a palette (generated for example with @ref{palettegen}) to encode a GIF
8095 using @command{ffmpeg}:
8097 ffmpeg -i input.mkv -i palette.png -lavfi paletteuse output.gif
8101 @section perspective
8103 Correct perspective of video not recorded perpendicular to the screen.
8105 A description of the accepted parameters follows.
8116 Set coordinates expression for top left, top right, bottom left and bottom right corners.
8117 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
8118 If the @code{sense} option is set to @code{source}, then the specified points will be sent
8119 to the corners of the destination. If the @code{sense} option is set to @code{destination},
8120 then the corners of the source will be sent to the specified coordinates.
8122 The expressions can use the following variables:
8127 the width and height of video frame.
8131 Set interpolation for perspective correction.
8133 It accepts the following values:
8139 Default value is @samp{linear}.
8142 Set interpretation of coordinate options.
8144 It accepts the following values:
8148 Send point in the source specified by the given coordinates to
8149 the corners of the destination.
8151 @item 1, destination
8153 Send the corners of the source to the point in the destination specified
8154 by the given coordinates.
8156 Default value is @samp{source}.
8162 Delay interlaced video by one field time so that the field order changes.
8164 The intended use is to fix PAL movies that have been captured with the
8165 opposite field order to the film-to-video transfer.
8167 A description of the accepted parameters follows.
8173 It accepts the following values:
8176 Capture field order top-first, transfer bottom-first.
8177 Filter will delay the bottom field.
8180 Capture field order bottom-first, transfer top-first.
8181 Filter will delay the top field.
8184 Capture and transfer with the same field order. This mode only exists
8185 for the documentation of the other options to refer to, but if you
8186 actually select it, the filter will faithfully do nothing.
8189 Capture field order determined automatically by field flags, transfer
8191 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
8192 basis using field flags. If no field information is available,
8193 then this works just like @samp{u}.
8196 Capture unknown or varying, transfer opposite.
8197 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
8198 analyzing the images and selecting the alternative that produces best
8199 match between the fields.
8202 Capture top-first, transfer unknown or varying.
8203 Filter selects among @samp{t} and @samp{p} using image analysis.
8206 Capture bottom-first, transfer unknown or varying.
8207 Filter selects among @samp{b} and @samp{p} using image analysis.
8210 Capture determined by field flags, transfer unknown or varying.
8211 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
8212 image analysis. If no field information is available, then this works just
8213 like @samp{U}. This is the default mode.
8216 Both capture and transfer unknown or varying.
8217 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
8221 @section pixdesctest
8223 Pixel format descriptor test filter, mainly useful for internal
8224 testing. The output video should be equal to the input video.
8228 format=monow, pixdesctest
8231 can be used to test the monowhite pixel format descriptor definition.
8235 Enable the specified chain of postprocessing subfilters using libpostproc. This
8236 library should be automatically selected with a GPL build (@code{--enable-gpl}).
8237 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
8238 Each subfilter and some options have a short and a long name that can be used
8239 interchangeably, i.e. dr/dering are the same.
8241 The filters accept the following options:
8245 Set postprocessing subfilters string.
8248 All subfilters share common options to determine their scope:
8252 Honor the quality commands for this subfilter.
8255 Do chrominance filtering, too (default).
8258 Do luminance filtering only (no chrominance).
8261 Do chrominance filtering only (no luminance).
8264 These options can be appended after the subfilter name, separated by a '|'.
8266 Available subfilters are:
8269 @item hb/hdeblock[|difference[|flatness]]
8270 Horizontal deblocking filter
8273 Difference factor where higher values mean more deblocking (default: @code{32}).
8275 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8278 @item vb/vdeblock[|difference[|flatness]]
8279 Vertical deblocking filter
8282 Difference factor where higher values mean more deblocking (default: @code{32}).
8284 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8287 @item ha/hadeblock[|difference[|flatness]]
8288 Accurate horizontal deblocking filter
8291 Difference factor where higher values mean more deblocking (default: @code{32}).
8293 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8296 @item va/vadeblock[|difference[|flatness]]
8297 Accurate vertical deblocking filter
8300 Difference factor where higher values mean more deblocking (default: @code{32}).
8302 Flatness threshold where lower values mean more deblocking (default: @code{39}).
8306 The horizontal and vertical deblocking filters share the difference and
8307 flatness values so you cannot set different horizontal and vertical
8312 Experimental horizontal deblocking filter
8315 Experimental vertical deblocking filter
8320 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
8323 larger -> stronger filtering
8325 larger -> stronger filtering
8327 larger -> stronger filtering
8330 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
8333 Stretch luminance to @code{0-255}.
8336 @item lb/linblenddeint
8337 Linear blend deinterlacing filter that deinterlaces the given block by
8338 filtering all lines with a @code{(1 2 1)} filter.
8340 @item li/linipoldeint
8341 Linear interpolating deinterlacing filter that deinterlaces the given block by
8342 linearly interpolating every second line.
8344 @item ci/cubicipoldeint
8345 Cubic interpolating deinterlacing filter deinterlaces the given block by
8346 cubically interpolating every second line.
8348 @item md/mediandeint
8349 Median deinterlacing filter that deinterlaces the given block by applying a
8350 median filter to every second line.
8352 @item fd/ffmpegdeint
8353 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
8354 second line with a @code{(-1 4 2 4 -1)} filter.
8357 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
8358 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
8360 @item fq/forceQuant[|quantizer]
8361 Overrides the quantizer table from the input with the constant quantizer you
8369 Default pp filter combination (@code{hb|a,vb|a,dr|a})
8372 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
8375 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
8378 @subsection Examples
8382 Apply horizontal and vertical deblocking, deringing and automatic
8383 brightness/contrast:
8389 Apply default filters without brightness/contrast correction:
8395 Apply default filters and temporal denoiser:
8397 pp=default/tmpnoise|1|2|3
8401 Apply deblocking on luminance only, and switch vertical deblocking on or off
8402 automatically depending on available CPU time:
8409 Apply Postprocessing filter 7. It is variant of the @ref{spp} filter,
8410 similar to spp = 6 with 7 point DCT, where only the center sample is
8413 The filter accepts the following options:
8417 Force a constant quantization parameter. It accepts an integer in range
8418 0 to 63. If not set, the filter will use the QP from the video stream
8422 Set thresholding mode. Available modes are:
8426 Set hard thresholding.
8428 Set soft thresholding (better de-ringing effect, but likely blurrier).
8430 Set medium thresholding (good results, default).
8436 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
8437 Ratio) between two input videos.
8439 This filter takes in input two input videos, the first input is
8440 considered the "main" source and is passed unchanged to the
8441 output. The second input is used as a "reference" video for computing
8444 Both video inputs must have the same resolution and pixel format for
8445 this filter to work correctly. Also it assumes that both inputs
8446 have the same number of frames, which are compared one by one.
8448 The obtained average PSNR is printed through the logging system.
8450 The filter stores the accumulated MSE (mean squared error) of each
8451 frame, and at the end of the processing it is averaged across all frames
8452 equally, and the following formula is applied to obtain the PSNR:
8455 PSNR = 10*log10(MAX^2/MSE)
8458 Where MAX is the average of the maximum values of each component of the
8461 The description of the accepted parameters follows.
8465 If specified the filter will use the named file to save the PSNR of
8466 each individual frame.
8469 The file printed if @var{stats_file} is selected, contains a sequence of
8470 key/value pairs of the form @var{key}:@var{value} for each compared
8473 A description of each shown parameter follows:
8477 sequential number of the input frame, starting from 1
8480 Mean Square Error pixel-by-pixel average difference of the compared
8481 frames, averaged over all the image components.
8483 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
8484 Mean Square Error pixel-by-pixel average difference of the compared
8485 frames for the component specified by the suffix.
8487 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
8488 Peak Signal to Noise ratio of the compared frames for the component
8489 specified by the suffix.
8494 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
8495 [main][ref] psnr="stats_file=stats.log" [out]
8498 On this example the input file being processed is compared with the
8499 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
8500 is stored in @file{stats.log}.
8505 Pulldown reversal (inverse telecine) filter, capable of handling mixed
8506 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
8509 The pullup filter is designed to take advantage of future context in making
8510 its decisions. This filter is stateless in the sense that it does not lock
8511 onto a pattern to follow, but it instead looks forward to the following
8512 fields in order to identify matches and rebuild progressive frames.
8514 To produce content with an even framerate, insert the fps filter after
8515 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
8516 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
8518 The filter accepts the following options:
8525 These options set the amount of "junk" to ignore at the left, right, top, and
8526 bottom of the image, respectively. Left and right are in units of 8 pixels,
8527 while top and bottom are in units of 2 lines.
8528 The default is 8 pixels on each side.
8531 Set the strict breaks. Setting this option to 1 will reduce the chances of
8532 filter generating an occasional mismatched frame, but it may also cause an
8533 excessive number of frames to be dropped during high motion sequences.
8534 Conversely, setting it to -1 will make filter match fields more easily.
8535 This may help processing of video where there is slight blurring between
8536 the fields, but may also cause there to be interlaced frames in the output.
8537 Default value is @code{0}.
8540 Set the metric plane to use. It accepts the following values:
8546 Use chroma blue plane.
8549 Use chroma red plane.
8552 This option may be set to use chroma plane instead of the default luma plane
8553 for doing filter's computations. This may improve accuracy on very clean
8554 source material, but more likely will decrease accuracy, especially if there
8555 is chroma noise (rainbow effect) or any grayscale video.
8556 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
8557 load and make pullup usable in realtime on slow machines.
8560 For best results (without duplicated frames in the output file) it is
8561 necessary to change the output frame rate. For example, to inverse
8562 telecine NTSC input:
8564 ffmpeg -i input -vf pullup -r 24000/1001 ...
8569 Change video quantization parameters (QP).
8571 The filter accepts the following option:
8575 Set expression for quantization parameter.
8578 The expression is evaluated through the eval API and can contain, among others,
8579 the following constants:
8583 1 if index is not 129, 0 otherwise.
8586 Sequentional index starting from -129 to 128.
8589 @subsection Examples
8601 Flush video frames from internal cache of frames into a random order.
8602 No frame is discarded.
8603 Inspired by @ref{frei0r} nervous filter.
8607 Set size in number of frames of internal cache, in range from @code{2} to
8608 @code{512}. Default is @code{30}.
8611 Set seed for random number generator, must be an integer included between
8612 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
8613 less than @code{0}, the filter will try to use a good random seed on a
8617 @section removegrain
8619 The removegrain filter is a spatial denoiser for progressive video.
8623 Set mode for the first plane.
8626 Set mode for the second plane.
8629 Set mode for the third plane.
8632 Set mode for the fourth plane.
8635 Range of mode is from 0 to 24. Description of each mode follows:
8639 Leave input plane unchanged. Default.
8642 Clips the pixel with the minimum and maximum of the 8 neighbour pixels.
8645 Clips the pixel with the second minimum and maximum of the 8 neighbour pixels.
8648 Clips the pixel with the third minimum and maximum of the 8 neighbour pixels.
8651 Clips the pixel with the fourth minimum and maximum of the 8 neighbour pixels.
8652 This is equivalent to a median filter.
8655 Line-sensitive clipping giving the minimal change.
8658 Line-sensitive clipping, intermediate.
8661 Line-sensitive clipping, intermediate.
8664 Line-sensitive clipping, intermediate.
8667 Line-sensitive clipping on a line where the neighbours pixels are the closest.
8670 Replaces the target pixel with the closest neighbour.
8673 [1 2 1] horizontal and vertical kernel blur.
8679 Bob mode, interpolates top field from the line where the neighbours
8680 pixels are the closest.
8683 Bob mode, interpolates bottom field from the line where the neighbours
8684 pixels are the closest.
8687 Bob mode, interpolates top field. Same as 13 but with a more complicated
8688 interpolation formula.
8691 Bob mode, interpolates bottom field. Same as 14 but with a more complicated
8692 interpolation formula.
8695 Clips the pixel with the minimum and maximum of respectively the maximum and
8696 minimum of each pair of opposite neighbour pixels.
8699 Line-sensitive clipping using opposite neighbours whose greatest distance from
8700 the current pixel is minimal.
8703 Replaces the pixel with the average of its 8 neighbours.
8706 Averages the 9 pixels ([1 1 1] horizontal and vertical blur).
8709 Clips pixels using the averages of opposite neighbour.
8712 Same as mode 21 but simpler and faster.
8715 Small edge and halo removal, but reputed useless.
8723 Suppress a TV station logo, using an image file to determine which
8724 pixels comprise the logo. It works by filling in the pixels that
8725 comprise the logo with neighboring pixels.
8727 The filter accepts the following options:
8731 Set the filter bitmap file, which can be any image format supported by
8732 libavformat. The width and height of the image file must match those of the
8733 video stream being processed.
8736 Pixels in the provided bitmap image with a value of zero are not
8737 considered part of the logo, non-zero pixels are considered part of
8738 the logo. If you use white (255) for the logo and black (0) for the
8739 rest, you will be safe. For making the filter bitmap, it is
8740 recommended to take a screen capture of a black frame with the logo
8741 visible, and then using a threshold filter followed by the erode
8742 filter once or twice.
8744 If needed, little splotches can be fixed manually. Remember that if
8745 logo pixels are not covered, the filter quality will be much
8746 reduced. Marking too many pixels as part of the logo does not hurt as
8747 much, but it will increase the amount of blurring needed to cover over
8748 the image and will destroy more information than necessary, and extra
8749 pixels will slow things down on a large logo.
8751 @section repeatfields
8753 This filter uses the repeat_field flag from the Video ES headers and hard repeats
8754 fields based on its value.
8756 @section reverse, areverse
8760 Warning: This filter requires memory to buffer the entire clip, so trimming
8763 @subsection Examples
8767 Take the first 5 seconds of a clip, and reverse it.
8775 Rotate video by an arbitrary angle expressed in radians.
8777 The filter accepts the following options:
8779 A description of the optional parameters follows.
8782 Set an expression for the angle by which to rotate the input video
8783 clockwise, expressed as a number of radians. A negative value will
8784 result in a counter-clockwise rotation. By default it is set to "0".
8786 This expression is evaluated for each frame.
8789 Set the output width expression, default value is "iw".
8790 This expression is evaluated just once during configuration.
8793 Set the output height expression, default value is "ih".
8794 This expression is evaluated just once during configuration.
8797 Enable bilinear interpolation if set to 1, a value of 0 disables
8798 it. Default value is 1.
8801 Set the color used to fill the output area not covered by the rotated
8802 image. For the general syntax of this option, check the "Color" section in the
8803 ffmpeg-utils manual. If the special value "none" is selected then no
8804 background is printed (useful for example if the background is never shown).
8806 Default value is "black".
8809 The expressions for the angle and the output size can contain the
8810 following constants and functions:
8814 sequential number of the input frame, starting from 0. It is always NAN
8815 before the first frame is filtered.
8818 time in seconds of the input frame, it is set to 0 when the filter is
8819 configured. It is always NAN before the first frame is filtered.
8823 horizontal and vertical chroma subsample values. For example for the
8824 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
8828 the input video width and height
8832 the output width and height, that is the size of the padded area as
8833 specified by the @var{width} and @var{height} expressions
8837 the minimal width/height required for completely containing the input
8838 video rotated by @var{a} radians.
8840 These are only available when computing the @option{out_w} and
8841 @option{out_h} expressions.
8844 @subsection Examples
8848 Rotate the input by PI/6 radians clockwise:
8854 Rotate the input by PI/6 radians counter-clockwise:
8860 Rotate the input by 45 degrees clockwise:
8866 Apply a constant rotation with period T, starting from an angle of PI/3:
8868 rotate=PI/3+2*PI*t/T
8872 Make the input video rotation oscillating with a period of T
8873 seconds and an amplitude of A radians:
8875 rotate=A*sin(2*PI/T*t)
8879 Rotate the video, output size is chosen so that the whole rotating
8880 input video is always completely contained in the output:
8882 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
8886 Rotate the video, reduce the output size so that no background is ever
8889 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
8893 @subsection Commands
8895 The filter supports the following commands:
8899 Set the angle expression.
8900 The command accepts the same syntax of the corresponding option.
8902 If the specified expression is not valid, it is kept at its current
8908 Apply Shape Adaptive Blur.
8910 The filter accepts the following options:
8913 @item luma_radius, lr
8914 Set luma blur filter strength, must be a value in range 0.1-4.0, default
8915 value is 1.0. A greater value will result in a more blurred image, and
8916 in slower processing.
8918 @item luma_pre_filter_radius, lpfr
8919 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
8922 @item luma_strength, ls
8923 Set luma maximum difference between pixels to still be considered, must
8924 be a value in the 0.1-100.0 range, default value is 1.0.
8926 @item chroma_radius, cr
8927 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
8928 greater value will result in a more blurred image, and in slower
8931 @item chroma_pre_filter_radius, cpfr
8932 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
8934 @item chroma_strength, cs
8935 Set chroma maximum difference between pixels to still be considered,
8936 must be a value in the 0.1-100.0 range.
8939 Each chroma option value, if not explicitly specified, is set to the
8940 corresponding luma option value.
8945 Scale (resize) the input video, using the libswscale library.
8947 The scale filter forces the output display aspect ratio to be the same
8948 of the input, by changing the output sample aspect ratio.
8950 If the input image format is different from the format requested by
8951 the next filter, the scale filter will convert the input to the
8955 The filter accepts the following options, or any of the options
8956 supported by the libswscale scaler.
8958 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
8959 the complete list of scaler options.
8964 Set the output video dimension expression. Default value is the input
8967 If the value is 0, the input width is used for the output.
8969 If one of the values is -1, the scale filter will use a value that
8970 maintains the aspect ratio of the input image, calculated from the
8971 other specified dimension. If both of them are -1, the input size is
8974 If one of the values is -n with n > 1, the scale filter will also use a value
8975 that maintains the aspect ratio of the input image, calculated from the other
8976 specified dimension. After that it will, however, make sure that the calculated
8977 dimension is divisible by n and adjust the value if necessary.
8979 See below for the list of accepted constants for use in the dimension
8983 Set the interlacing mode. It accepts the following values:
8987 Force interlaced aware scaling.
8990 Do not apply interlaced scaling.
8993 Select interlaced aware scaling depending on whether the source frames
8994 are flagged as interlaced or not.
8997 Default value is @samp{0}.
9000 Set libswscale scaling flags. See
9001 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
9002 complete list of values. If not explicitly specified the filter applies
9006 Set the video size. For the syntax of this option, check the
9007 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
9009 @item in_color_matrix
9010 @item out_color_matrix
9011 Set in/output YCbCr color space type.
9013 This allows the autodetected value to be overridden as well as allows forcing
9014 a specific value used for the output and encoder.
9016 If not specified, the color space type depends on the pixel format.
9022 Choose automatically.
9025 Format conforming to International Telecommunication Union (ITU)
9026 Recommendation BT.709.
9029 Set color space conforming to the United States Federal Communications
9030 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
9033 Set color space conforming to:
9037 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
9040 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
9043 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
9048 Set color space conforming to SMPTE ST 240:1999.
9053 Set in/output YCbCr sample range.
9055 This allows the autodetected value to be overridden as well as allows forcing
9056 a specific value used for the output and encoder. If not specified, the
9057 range depends on the pixel format. Possible values:
9061 Choose automatically.
9064 Set full range (0-255 in case of 8-bit luma).
9067 Set "MPEG" range (16-235 in case of 8-bit luma).
9070 @item force_original_aspect_ratio
9071 Enable decreasing or increasing output video width or height if necessary to
9072 keep the original aspect ratio. Possible values:
9076 Scale the video as specified and disable this feature.
9079 The output video dimensions will automatically be decreased if needed.
9082 The output video dimensions will automatically be increased if needed.
9086 One useful instance of this option is that when you know a specific device's
9087 maximum allowed resolution, you can use this to limit the output video to
9088 that, while retaining the aspect ratio. For example, device A allows
9089 1280x720 playback, and your video is 1920x800. Using this option (set it to
9090 decrease) and specifying 1280x720 to the command line makes the output
9093 Please note that this is a different thing than specifying -1 for @option{w}
9094 or @option{h}, you still need to specify the output resolution for this option
9099 The values of the @option{w} and @option{h} options are expressions
9100 containing the following constants:
9105 The input width and height
9109 These are the same as @var{in_w} and @var{in_h}.
9113 The output (scaled) width and height
9117 These are the same as @var{out_w} and @var{out_h}
9120 The same as @var{iw} / @var{ih}
9123 input sample aspect ratio
9126 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
9130 horizontal and vertical input chroma subsample values. For example for the
9131 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9135 horizontal and vertical output chroma subsample values. For example for the
9136 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9139 @subsection Examples
9143 Scale the input video to a size of 200x100
9148 This is equivalent to:
9159 Specify a size abbreviation for the output size:
9164 which can also be written as:
9170 Scale the input to 2x:
9176 The above is the same as:
9182 Scale the input to 2x with forced interlaced scaling:
9184 scale=2*iw:2*ih:interl=1
9188 Scale the input to half size:
9194 Increase the width, and set the height to the same size:
9207 Increase the height, and set the width to 3/2 of the height:
9209 scale=w=3/2*oh:h=3/5*ih
9213 Increase the size, making the size a multiple of the chroma
9216 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
9220 Increase the width to a maximum of 500 pixels,
9221 keeping the same aspect ratio as the input:
9223 scale=w='min(500\, iw*3/2):h=-1'
9227 @subsection Commands
9229 This filter supports the following commands:
9233 Set the output video dimension expression.
9234 The command accepts the same syntax of the corresponding option.
9236 If the specified expression is not valid, it is kept at its current
9242 Scale (resize) the input video, based on a reference video.
9244 See the scale filter for available options, scale2ref supports the same but
9245 uses the reference video instead of the main input as basis.
9247 @subsection Examples
9251 Scale a subtitle stream to match the main video in size before overlaying
9253 'scale2ref[b][a];[a][b]overlay'
9257 @section separatefields
9259 The @code{separatefields} takes a frame-based video input and splits
9260 each frame into its components fields, producing a new half height clip
9261 with twice the frame rate and twice the frame count.
9263 This filter use field-dominance information in frame to decide which
9264 of each pair of fields to place first in the output.
9265 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
9267 @section setdar, setsar
9269 The @code{setdar} filter sets the Display Aspect Ratio for the filter
9272 This is done by changing the specified Sample (aka Pixel) Aspect
9273 Ratio, according to the following equation:
9275 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
9278 Keep in mind that the @code{setdar} filter does not modify the pixel
9279 dimensions of the video frame. Also, the display aspect ratio set by
9280 this filter may be changed by later filters in the filterchain,
9281 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
9284 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
9285 the filter output video.
9287 Note that as a consequence of the application of this filter, the
9288 output display aspect ratio will change according to the equation
9291 Keep in mind that the sample aspect ratio set by the @code{setsar}
9292 filter may be changed by later filters in the filterchain, e.g. if
9293 another "setsar" or a "setdar" filter is applied.
9295 It accepts the following parameters:
9298 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
9299 Set the aspect ratio used by the filter.
9301 The parameter can be a floating point number string, an expression, or
9302 a string of the form @var{num}:@var{den}, where @var{num} and
9303 @var{den} are the numerator and denominator of the aspect ratio. If
9304 the parameter is not specified, it is assumed the value "0".
9305 In case the form "@var{num}:@var{den}" is used, the @code{:} character
9309 Set the maximum integer value to use for expressing numerator and
9310 denominator when reducing the expressed aspect ratio to a rational.
9311 Default value is @code{100}.
9315 The parameter @var{sar} is an expression containing
9316 the following constants:
9320 These are approximated values for the mathematical constants e
9321 (Euler's number), pi (Greek pi), and phi (the golden ratio).
9324 The input width and height.
9327 These are the same as @var{w} / @var{h}.
9330 The input sample aspect ratio.
9333 The input display aspect ratio. It is the same as
9334 (@var{w} / @var{h}) * @var{sar}.
9337 Horizontal and vertical chroma subsample values. For example, for the
9338 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
9341 @subsection Examples
9346 To change the display aspect ratio to 16:9, specify one of the following:
9354 To change the sample aspect ratio to 10:11, specify:
9360 To set a display aspect ratio of 16:9, and specify a maximum integer value of
9361 1000 in the aspect ratio reduction, use the command:
9363 setdar=ratio=16/9:max=1000
9371 Force field for the output video frame.
9373 The @code{setfield} filter marks the interlace type field for the
9374 output frames. It does not change the input frame, but only sets the
9375 corresponding property, which affects how the frame is treated by
9376 following filters (e.g. @code{fieldorder} or @code{yadif}).
9378 The filter accepts the following options:
9383 Available values are:
9387 Keep the same field property.
9390 Mark the frame as bottom-field-first.
9393 Mark the frame as top-field-first.
9396 Mark the frame as progressive.
9402 Show a line containing various information for each input video frame.
9403 The input video is not modified.
9405 The shown line contains a sequence of key/value pairs of the form
9406 @var{key}:@var{value}.
9408 The following values are shown in the output:
9412 The (sequential) number of the input frame, starting from 0.
9415 The Presentation TimeStamp of the input frame, expressed as a number of
9416 time base units. The time base unit depends on the filter input pad.
9419 The Presentation TimeStamp of the input frame, expressed as a number of
9423 The position of the frame in the input stream, or -1 if this information is
9424 unavailable and/or meaningless (for example in case of synthetic video).
9427 The pixel format name.
9430 The sample aspect ratio of the input frame, expressed in the form
9431 @var{num}/@var{den}.
9434 The size of the input frame. For the syntax of this option, check the
9435 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
9438 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
9439 for bottom field first).
9442 This is 1 if the frame is a key frame, 0 otherwise.
9445 The picture type of the input frame ("I" for an I-frame, "P" for a
9446 P-frame, "B" for a B-frame, or "?" for an unknown type).
9447 Also refer to the documentation of the @code{AVPictureType} enum and of
9448 the @code{av_get_picture_type_char} function defined in
9449 @file{libavutil/avutil.h}.
9452 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
9454 @item plane_checksum
9455 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
9456 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
9459 @section showpalette
9461 Displays the 256 colors palette of each frame. This filter is only relevant for
9462 @var{pal8} pixel format frames.
9464 It accepts the following option:
9468 Set the size of the box used to represent one palette color entry. Default is
9469 @code{30} (for a @code{30x30} pixel box).
9472 @section shuffleplanes
9474 Reorder and/or duplicate video planes.
9476 It accepts the following parameters:
9481 The index of the input plane to be used as the first output plane.
9484 The index of the input plane to be used as the second output plane.
9487 The index of the input plane to be used as the third output plane.
9490 The index of the input plane to be used as the fourth output plane.
9494 The first plane has the index 0. The default is to keep the input unchanged.
9496 Swap the second and third planes of the input:
9498 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
9501 @anchor{signalstats}
9502 @section signalstats
9503 Evaluate various visual metrics that assist in determining issues associated
9504 with the digitization of analog video media.
9506 By default the filter will log these metadata values:
9510 Display the minimal Y value contained within the input frame. Expressed in
9514 Display the Y value at the 10% percentile within the input frame. Expressed in
9518 Display the average Y value within the input frame. Expressed in range of
9522 Display the Y value at the 90% percentile within the input frame. Expressed in
9526 Display the maximum Y value contained within the input frame. Expressed in
9530 Display the minimal U value contained within the input frame. Expressed in
9534 Display the U value at the 10% percentile within the input frame. Expressed in
9538 Display the average U value within the input frame. Expressed in range of
9542 Display the U value at the 90% percentile within the input frame. Expressed in
9546 Display the maximum U value contained within the input frame. Expressed in
9550 Display the minimal V value contained within the input frame. Expressed in
9554 Display the V value at the 10% percentile within the input frame. Expressed in
9558 Display the average V value within the input frame. Expressed in range of
9562 Display the V value at the 90% percentile within the input frame. Expressed in
9566 Display the maximum V value contained within the input frame. Expressed in
9570 Display the minimal saturation value contained within the input frame.
9571 Expressed in range of [0-~181.02].
9574 Display the saturation value at the 10% percentile within the input frame.
9575 Expressed in range of [0-~181.02].
9578 Display the average saturation value within the input frame. Expressed in range
9582 Display the saturation value at the 90% percentile within the input frame.
9583 Expressed in range of [0-~181.02].
9586 Display the maximum saturation value contained within the input frame.
9587 Expressed in range of [0-~181.02].
9590 Display the median value for hue within the input frame. Expressed in range of
9594 Display the average value for hue within the input frame. Expressed in range of
9598 Display the average of sample value difference between all values of the Y
9599 plane in the current frame and corresponding values of the previous input frame.
9600 Expressed in range of [0-255].
9603 Display the average of sample value difference between all values of the U
9604 plane in the current frame and corresponding values of the previous input frame.
9605 Expressed in range of [0-255].
9608 Display the average of sample value difference between all values of the V
9609 plane in the current frame and corresponding values of the previous input frame.
9610 Expressed in range of [0-255].
9613 The filter accepts the following options:
9619 @option{stat} specify an additional form of image analysis.
9620 @option{out} output video with the specified type of pixel highlighted.
9622 Both options accept the following values:
9626 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
9627 unlike the neighboring pixels of the same field. Examples of temporal outliers
9628 include the results of video dropouts, head clogs, or tape tracking issues.
9631 Identify @var{vertical line repetition}. Vertical line repetition includes
9632 similar rows of pixels within a frame. In born-digital video vertical line
9633 repetition is common, but this pattern is uncommon in video digitized from an
9634 analog source. When it occurs in video that results from the digitization of an
9635 analog source it can indicate concealment from a dropout compensator.
9638 Identify pixels that fall outside of legal broadcast range.
9642 Set the highlight color for the @option{out} option. The default color is
9646 @subsection Examples
9650 Output data of various video metrics:
9652 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
9656 Output specific data about the minimum and maximum values of the Y plane per frame:
9658 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
9662 Playback video while highlighting pixels that are outside of broadcast range in red.
9664 ffplay example.mov -vf signalstats="out=brng:color=red"
9668 Playback video with signalstats metadata drawn over the frame.
9670 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
9673 The contents of signalstat_drawtext.txt used in the command are:
9676 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
9677 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
9678 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
9679 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
9687 Blur the input video without impacting the outlines.
9689 It accepts the following options:
9692 @item luma_radius, lr
9693 Set the luma radius. The option value must be a float number in
9694 the range [0.1,5.0] that specifies the variance of the gaussian filter
9695 used to blur the image (slower if larger). Default value is 1.0.
9697 @item luma_strength, ls
9698 Set the luma strength. The option value must be a float number
9699 in the range [-1.0,1.0] that configures the blurring. A value included
9700 in [0.0,1.0] will blur the image whereas a value included in
9701 [-1.0,0.0] will sharpen the image. Default value is 1.0.
9703 @item luma_threshold, lt
9704 Set the luma threshold used as a coefficient to determine
9705 whether a pixel should be blurred or not. The option value must be an
9706 integer in the range [-30,30]. A value of 0 will filter all the image,
9707 a value included in [0,30] will filter flat areas and a value included
9708 in [-30,0] will filter edges. Default value is 0.
9710 @item chroma_radius, cr
9711 Set the chroma radius. The option value must be a float number in
9712 the range [0.1,5.0] that specifies the variance of the gaussian filter
9713 used to blur the image (slower if larger). Default value is 1.0.
9715 @item chroma_strength, cs
9716 Set the chroma strength. The option value must be a float number
9717 in the range [-1.0,1.0] that configures the blurring. A value included
9718 in [0.0,1.0] will blur the image whereas a value included in
9719 [-1.0,0.0] will sharpen the image. Default value is 1.0.
9721 @item chroma_threshold, ct
9722 Set the chroma threshold used as a coefficient to determine
9723 whether a pixel should be blurred or not. The option value must be an
9724 integer in the range [-30,30]. A value of 0 will filter all the image,
9725 a value included in [0,30] will filter flat areas and a value included
9726 in [-30,0] will filter edges. Default value is 0.
9729 If a chroma option is not explicitly set, the corresponding luma value
9734 Obtain the SSIM (Structural SImilarity Metric) between two input videos.
9736 This filter takes in input two input videos, the first input is
9737 considered the "main" source and is passed unchanged to the
9738 output. The second input is used as a "reference" video for computing
9741 Both video inputs must have the same resolution and pixel format for
9742 this filter to work correctly. Also it assumes that both inputs
9743 have the same number of frames, which are compared one by one.
9745 The filter stores the calculated SSIM of each frame.
9747 The description of the accepted parameters follows.
9751 If specified the filter will use the named file to save the SSIM of
9752 each individual frame.
9755 The file printed if @var{stats_file} is selected, contains a sequence of
9756 key/value pairs of the form @var{key}:@var{value} for each compared
9759 A description of each shown parameter follows:
9763 sequential number of the input frame, starting from 1
9765 @item Y, U, V, R, G, B
9766 SSIM of the compared frames for the component specified by the suffix.
9769 SSIM of the compared frames for the whole frame.
9772 Same as above but in dB representation.
9777 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
9778 [main][ref] ssim="stats_file=stats.log" [out]
9781 On this example the input file being processed is compared with the
9782 reference file @file{ref_movie.mpg}. The SSIM of each individual frame
9783 is stored in @file{stats.log}.
9785 Another example with both psnr and ssim at same time:
9787 ffmpeg -i main.mpg -i ref.mpg -lavfi "ssim;[0:v][1:v]psnr" -f null -
9792 Convert between different stereoscopic image formats.
9794 The filters accept the following options:
9798 Set stereoscopic image format of input.
9800 Available values for input image formats are:
9803 side by side parallel (left eye left, right eye right)
9806 side by side crosseye (right eye left, left eye right)
9809 side by side parallel with half width resolution
9810 (left eye left, right eye right)
9813 side by side crosseye with half width resolution
9814 (right eye left, left eye right)
9817 above-below (left eye above, right eye below)
9820 above-below (right eye above, left eye below)
9823 above-below with half height resolution
9824 (left eye above, right eye below)
9827 above-below with half height resolution
9828 (right eye above, left eye below)
9831 alternating frames (left eye first, right eye second)
9834 alternating frames (right eye first, left eye second)
9837 interleaved rows (left eye has top row, right eye starts on next row)
9840 interleaved rows (right eye has top row, left eye starts on next row)
9842 Default value is @samp{sbsl}.
9846 Set stereoscopic image format of output.
9848 Available values for output image formats are all the input formats as well as:
9851 anaglyph red/blue gray
9852 (red filter on left eye, blue filter on right eye)
9855 anaglyph red/green gray
9856 (red filter on left eye, green filter on right eye)
9859 anaglyph red/cyan gray
9860 (red filter on left eye, cyan filter on right eye)
9863 anaglyph red/cyan half colored
9864 (red filter on left eye, cyan filter on right eye)
9867 anaglyph red/cyan color
9868 (red filter on left eye, cyan filter on right eye)
9871 anaglyph red/cyan color optimized with the least squares projection of dubois
9872 (red filter on left eye, cyan filter on right eye)
9875 anaglyph green/magenta gray
9876 (green filter on left eye, magenta filter on right eye)
9879 anaglyph green/magenta half colored
9880 (green filter on left eye, magenta filter on right eye)
9883 anaglyph green/magenta colored
9884 (green filter on left eye, magenta filter on right eye)
9887 anaglyph green/magenta color optimized with the least squares projection of dubois
9888 (green filter on left eye, magenta filter on right eye)
9891 anaglyph yellow/blue gray
9892 (yellow filter on left eye, blue filter on right eye)
9895 anaglyph yellow/blue half colored
9896 (yellow filter on left eye, blue filter on right eye)
9899 anaglyph yellow/blue colored
9900 (yellow filter on left eye, blue filter on right eye)
9903 anaglyph yellow/blue color optimized with the least squares projection of dubois
9904 (yellow filter on left eye, blue filter on right eye)
9907 mono output (left eye only)
9910 mono output (right eye only)
9913 checkerboard, left eye first
9916 checkerboard, right eye first
9919 interleaved columns, left eye first
9922 interleaved columns, right eye first
9925 Default value is @samp{arcd}.
9928 @subsection Examples
9932 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
9938 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
9947 Apply a simple postprocessing filter that compresses and decompresses the image
9948 at several (or - in the case of @option{quality} level @code{6} - all) shifts
9949 and average the results.
9951 The filter accepts the following options:
9955 Set quality. This option defines the number of levels for averaging. It accepts
9956 an integer in the range 0-6. If set to @code{0}, the filter will have no
9957 effect. A value of @code{6} means the higher quality. For each increment of
9958 that value the speed drops by a factor of approximately 2. Default value is
9962 Force a constant quantization parameter. If not set, the filter will use the QP
9963 from the video stream (if available).
9966 Set thresholding mode. Available modes are:
9970 Set hard thresholding (default).
9972 Set soft thresholding (better de-ringing effect, but likely blurrier).
9976 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
9977 option may cause flicker since the B-Frames have often larger QP. Default is
9978 @code{0} (not enabled).
9984 Draw subtitles on top of input video using the libass library.
9986 To enable compilation of this filter you need to configure FFmpeg with
9987 @code{--enable-libass}. This filter also requires a build with libavcodec and
9988 libavformat to convert the passed subtitles file to ASS (Advanced Substation
9989 Alpha) subtitles format.
9991 The filter accepts the following options:
9995 Set the filename of the subtitle file to read. It must be specified.
9998 Specify the size of the original video, the video for which the ASS file
9999 was composed. For the syntax of this option, check the
10000 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10001 Due to a misdesign in ASS aspect ratio arithmetic, this is necessary to
10002 correctly scale the fonts if the aspect ratio has been changed.
10005 Set a directory path containing fonts that can be used by the filter.
10006 These fonts will be used in addition to whatever the font provider uses.
10009 Set subtitles input character encoding. @code{subtitles} filter only. Only
10010 useful if not UTF-8.
10012 @item stream_index, si
10013 Set subtitles stream index. @code{subtitles} filter only.
10016 Override default style or script info parameters of the subtitles. It accepts a
10017 string containing ASS style format @code{KEY=VALUE} couples separated by ",".
10020 If the first key is not specified, it is assumed that the first value
10021 specifies the @option{filename}.
10023 For example, to render the file @file{sub.srt} on top of the input
10024 video, use the command:
10029 which is equivalent to:
10031 subtitles=filename=sub.srt
10034 To render the default subtitles stream from file @file{video.mkv}, use:
10036 subtitles=video.mkv
10039 To render the second subtitles stream from that file, use:
10041 subtitles=video.mkv:si=1
10044 To make the subtitles stream from @file{sub.srt} appear in transparent green
10045 @code{DejaVu Serif}, use:
10047 subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'
10050 @section super2xsai
10052 Scale the input by 2x and smooth using the Super2xSaI (Scale and
10053 Interpolate) pixel art scaling algorithm.
10055 Useful for enlarging pixel art images without reducing sharpness.
10062 Apply telecine process to the video.
10064 This filter accepts the following options:
10073 The default value is @code{top}.
10077 A string of numbers representing the pulldown pattern you wish to apply.
10078 The default value is @code{23}.
10082 Some typical patterns:
10087 24p: 2332 (preferred)
10094 24p: 222222222223 ("Euro pulldown")
10100 Select the most representative frame in a given sequence of consecutive frames.
10102 The filter accepts the following options:
10106 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
10107 will pick one of them, and then handle the next batch of @var{n} frames until
10108 the end. Default is @code{100}.
10111 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
10112 value will result in a higher memory usage, so a high value is not recommended.
10114 @subsection Examples
10118 Extract one picture each 50 frames:
10124 Complete example of a thumbnail creation with @command{ffmpeg}:
10126 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
10132 Tile several successive frames together.
10134 The filter accepts the following options:
10139 Set the grid size (i.e. the number of lines and columns). For the syntax of
10140 this option, check the
10141 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
10144 Set the maximum number of frames to render in the given area. It must be less
10145 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
10146 the area will be used.
10149 Set the outer border margin in pixels.
10152 Set the inner border thickness (i.e. the number of pixels between frames). For
10153 more advanced padding options (such as having different values for the edges),
10154 refer to the pad video filter.
10157 Specify the color of the unused area. For the syntax of this option, check the
10158 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
10162 @subsection Examples
10166 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
10168 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
10170 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
10171 duplicating each output frame to accommodate the originally detected frame
10175 Display @code{5} pictures in an area of @code{3x2} frames,
10176 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
10177 mixed flat and named options:
10179 tile=3x2:nb_frames=5:padding=7:margin=2
10183 @section tinterlace
10185 Perform various types of temporal field interlacing.
10187 Frames are counted starting from 1, so the first input frame is
10190 The filter accepts the following options:
10195 Specify the mode of the interlacing. This option can also be specified
10196 as a value alone. See below for a list of values for this option.
10198 Available values are:
10202 Move odd frames into the upper field, even into the lower field,
10203 generating a double height frame at half frame rate.
10207 Frame 1 Frame 2 Frame 3 Frame 4
10209 11111 22222 33333 44444
10210 11111 22222 33333 44444
10211 11111 22222 33333 44444
10212 11111 22222 33333 44444
10226 Only output even frames, odd frames are dropped, generating a frame with
10227 unchanged height at half frame rate.
10232 Frame 1 Frame 2 Frame 3 Frame 4
10234 11111 22222 33333 44444
10235 11111 22222 33333 44444
10236 11111 22222 33333 44444
10237 11111 22222 33333 44444
10247 Only output odd frames, even frames are dropped, generating a frame with
10248 unchanged height at half frame rate.
10253 Frame 1 Frame 2 Frame 3 Frame 4
10255 11111 22222 33333 44444
10256 11111 22222 33333 44444
10257 11111 22222 33333 44444
10258 11111 22222 33333 44444
10268 Expand each frame to full height, but pad alternate lines with black,
10269 generating a frame with double height at the same input frame rate.
10274 Frame 1 Frame 2 Frame 3 Frame 4
10276 11111 22222 33333 44444
10277 11111 22222 33333 44444
10278 11111 22222 33333 44444
10279 11111 22222 33333 44444
10282 11111 ..... 33333 .....
10283 ..... 22222 ..... 44444
10284 11111 ..... 33333 .....
10285 ..... 22222 ..... 44444
10286 11111 ..... 33333 .....
10287 ..... 22222 ..... 44444
10288 11111 ..... 33333 .....
10289 ..... 22222 ..... 44444
10293 @item interleave_top, 4
10294 Interleave the upper field from odd frames with the lower field from
10295 even frames, generating a frame with unchanged height at half frame rate.
10300 Frame 1 Frame 2 Frame 3 Frame 4
10302 11111<- 22222 33333<- 44444
10303 11111 22222<- 33333 44444<-
10304 11111<- 22222 33333<- 44444
10305 11111 22222<- 33333 44444<-
10315 @item interleave_bottom, 5
10316 Interleave the lower field from odd frames with the upper field from
10317 even frames, generating a frame with unchanged height at half frame rate.
10322 Frame 1 Frame 2 Frame 3 Frame 4
10324 11111 22222<- 33333 44444<-
10325 11111<- 22222 33333<- 44444
10326 11111 22222<- 33333 44444<-
10327 11111<- 22222 33333<- 44444
10337 @item interlacex2, 6
10338 Double frame rate with unchanged height. Frames are inserted each
10339 containing the second temporal field from the previous input frame and
10340 the first temporal field from the next input frame. This mode relies on
10341 the top_field_first flag. Useful for interlaced video displays with no
10342 field synchronisation.
10347 Frame 1 Frame 2 Frame 3 Frame 4
10349 11111 22222 33333 44444
10350 11111 22222 33333 44444
10351 11111 22222 33333 44444
10352 11111 22222 33333 44444
10355 11111 22222 22222 33333 33333 44444 44444
10356 11111 11111 22222 22222 33333 33333 44444
10357 11111 22222 22222 33333 33333 44444 44444
10358 11111 11111 22222 22222 33333 33333 44444
10364 Numeric values are deprecated but are accepted for backward
10365 compatibility reasons.
10367 Default mode is @code{merge}.
10370 Specify flags influencing the filter process.
10372 Available value for @var{flags} is:
10375 @item low_pass_filter, vlfp
10376 Enable vertical low-pass filtering in the filter.
10377 Vertical low-pass filtering is required when creating an interlaced
10378 destination from a progressive source which contains high-frequency
10379 vertical detail. Filtering will reduce interlace 'twitter' and Moire
10382 Vertical low-pass filtering can only be enabled for @option{mode}
10383 @var{interleave_top} and @var{interleave_bottom}.
10390 Transpose rows with columns in the input video and optionally flip it.
10392 It accepts the following parameters:
10397 Specify the transposition direction.
10399 Can assume the following values:
10401 @item 0, 4, cclock_flip
10402 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
10410 Rotate by 90 degrees clockwise, that is:
10418 Rotate by 90 degrees counterclockwise, that is:
10425 @item 3, 7, clock_flip
10426 Rotate by 90 degrees clockwise and vertically flip, that is:
10434 For values between 4-7, the transposition is only done if the input
10435 video geometry is portrait and not landscape. These values are
10436 deprecated, the @code{passthrough} option should be used instead.
10438 Numerical values are deprecated, and should be dropped in favor of
10439 symbolic constants.
10442 Do not apply the transposition if the input geometry matches the one
10443 specified by the specified value. It accepts the following values:
10446 Always apply transposition.
10448 Preserve portrait geometry (when @var{height} >= @var{width}).
10450 Preserve landscape geometry (when @var{width} >= @var{height}).
10453 Default value is @code{none}.
10456 For example to rotate by 90 degrees clockwise and preserve portrait
10459 transpose=dir=1:passthrough=portrait
10462 The command above can also be specified as:
10464 transpose=1:portrait
10468 Trim the input so that the output contains one continuous subpart of the input.
10470 It accepts the following parameters:
10473 Specify the time of the start of the kept section, i.e. the frame with the
10474 timestamp @var{start} will be the first frame in the output.
10477 Specify the time of the first frame that will be dropped, i.e. the frame
10478 immediately preceding the one with the timestamp @var{end} will be the last
10479 frame in the output.
10482 This is the same as @var{start}, except this option sets the start timestamp
10483 in timebase units instead of seconds.
10486 This is the same as @var{end}, except this option sets the end timestamp
10487 in timebase units instead of seconds.
10490 The maximum duration of the output in seconds.
10493 The number of the first frame that should be passed to the output.
10496 The number of the first frame that should be dropped.
10499 @option{start}, @option{end}, and @option{duration} are expressed as time
10500 duration specifications; see
10501 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
10502 for the accepted syntax.
10504 Note that the first two sets of the start/end options and the @option{duration}
10505 option look at the frame timestamp, while the _frame variants simply count the
10506 frames that pass through the filter. Also note that this filter does not modify
10507 the timestamps. If you wish for the output timestamps to start at zero, insert a
10508 setpts filter after the trim filter.
10510 If multiple start or end options are set, this filter tries to be greedy and
10511 keep all the frames that match at least one of the specified constraints. To keep
10512 only the part that matches all the constraints at once, chain multiple trim
10515 The defaults are such that all the input is kept. So it is possible to set e.g.
10516 just the end values to keep everything before the specified time.
10521 Drop everything except the second minute of input:
10523 ffmpeg -i INPUT -vf trim=60:120
10527 Keep only the first second:
10529 ffmpeg -i INPUT -vf trim=duration=1
10538 Sharpen or blur the input video.
10540 It accepts the following parameters:
10543 @item luma_msize_x, lx
10544 Set the luma matrix horizontal size. It must be an odd integer between
10545 3 and 63. The default value is 5.
10547 @item luma_msize_y, ly
10548 Set the luma matrix vertical size. It must be an odd integer between 3
10549 and 63. The default value is 5.
10551 @item luma_amount, la
10552 Set the luma effect strength. It must be a floating point number, reasonable
10553 values lay between -1.5 and 1.5.
10555 Negative values will blur the input video, while positive values will
10556 sharpen it, a value of zero will disable the effect.
10558 Default value is 1.0.
10560 @item chroma_msize_x, cx
10561 Set the chroma matrix horizontal size. It must be an odd integer
10562 between 3 and 63. The default value is 5.
10564 @item chroma_msize_y, cy
10565 Set the chroma matrix vertical size. It must be an odd integer
10566 between 3 and 63. The default value is 5.
10568 @item chroma_amount, ca
10569 Set the chroma effect strength. It must be a floating point number, reasonable
10570 values lay between -1.5 and 1.5.
10572 Negative values will blur the input video, while positive values will
10573 sharpen it, a value of zero will disable the effect.
10575 Default value is 0.0.
10578 If set to 1, specify using OpenCL capabilities, only available if
10579 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
10583 All parameters are optional and default to the equivalent of the
10584 string '5:5:1.0:5:5:0.0'.
10586 @subsection Examples
10590 Apply strong luma sharpen effect:
10592 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
10596 Apply a strong blur of both luma and chroma parameters:
10598 unsharp=7:7:-2:7:7:-2
10604 Apply ultra slow/simple postprocessing filter that compresses and decompresses
10605 the image at several (or - in the case of @option{quality} level @code{8} - all)
10606 shifts and average the results.
10608 The way this differs from the behavior of spp is that uspp actually encodes &
10609 decodes each case with libavcodec Snow, whereas spp uses a simplified intra only 8x8
10610 DCT similar to MJPEG.
10612 The filter accepts the following options:
10616 Set quality. This option defines the number of levels for averaging. It accepts
10617 an integer in the range 0-8. If set to @code{0}, the filter will have no
10618 effect. A value of @code{8} means the higher quality. For each increment of
10619 that value the speed drops by a factor of approximately 2. Default value is
10623 Force a constant quantization parameter. If not set, the filter will use the QP
10624 from the video stream (if available).
10627 @section vectorscope
10629 Display 2 color component values in the two dimensional graph (which is called
10632 This filter accepts the following options:
10636 Set vectorscope mode.
10638 It accepts the following values:
10641 Gray values are displayed on graph, higher brightness means more pixels have
10642 same component color value on location in graph. This is the default mode.
10645 Gray values are displayed on graph. Surrounding pixels values which are not
10646 present in video frame are drawn in gradient of 2 color components which are
10647 set by option @code{x} and @code{y}.
10650 Actual color components values present in video frame are displayed on graph.
10653 Similar as color2 but higher frequency of same values @code{x} and @code{y}
10654 on graph increases value of another color component, which is luminance by
10655 default values of @code{x} and @code{y}.
10658 Actual colors present in video frame are displayed on graph. If two different
10659 colors map to same position on graph then color with higher value of component
10660 not present in graph is picked.
10664 Set which color component will be represented on X-axis. Default is @code{1}.
10667 Set which color component will be represented on Y-axis. Default is @code{2}.
10670 Set intensity, used by modes: gray, color and color3 for increasing brightness
10671 of color component which represents frequency of (X, Y) location in graph.
10676 No envelope, this is default.
10679 Instant envelope, even darkest single pixel will be clearly highlighted.
10682 Hold maximum and minimum values presented in graph over time. This way you
10683 can still spot out of range values without constantly looking at vectorscope.
10686 Peak and instant envelope combined together.
10690 @anchor{vidstabdetect}
10691 @section vidstabdetect
10693 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
10694 @ref{vidstabtransform} for pass 2.
10696 This filter generates a file with relative translation and rotation
10697 transform information about subsequent frames, which is then used by
10698 the @ref{vidstabtransform} filter.
10700 To enable compilation of this filter you need to configure FFmpeg with
10701 @code{--enable-libvidstab}.
10703 This filter accepts the following options:
10707 Set the path to the file used to write the transforms information.
10708 Default value is @file{transforms.trf}.
10711 Set how shaky the video is and how quick the camera is. It accepts an
10712 integer in the range 1-10, a value of 1 means little shakiness, a
10713 value of 10 means strong shakiness. Default value is 5.
10716 Set the accuracy of the detection process. It must be a value in the
10717 range 1-15. A value of 1 means low accuracy, a value of 15 means high
10718 accuracy. Default value is 15.
10721 Set stepsize of the search process. The region around minimum is
10722 scanned with 1 pixel resolution. Default value is 6.
10725 Set minimum contrast. Below this value a local measurement field is
10726 discarded. Must be a floating point value in the range 0-1. Default
10730 Set reference frame number for tripod mode.
10732 If enabled, the motion of the frames is compared to a reference frame
10733 in the filtered stream, identified by the specified number. The idea
10734 is to compensate all movements in a more-or-less static scene and keep
10735 the camera view absolutely still.
10737 If set to 0, it is disabled. The frames are counted starting from 1.
10740 Show fields and transforms in the resulting frames. It accepts an
10741 integer in the range 0-2. Default value is 0, which disables any
10745 @subsection Examples
10749 Use default values:
10755 Analyze strongly shaky movie and put the results in file
10756 @file{mytransforms.trf}:
10758 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
10762 Visualize the result of internal transformations in the resulting
10765 vidstabdetect=show=1
10769 Analyze a video with medium shakiness using @command{ffmpeg}:
10771 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
10775 @anchor{vidstabtransform}
10776 @section vidstabtransform
10778 Video stabilization/deshaking: pass 2 of 2,
10779 see @ref{vidstabdetect} for pass 1.
10781 Read a file with transform information for each frame and
10782 apply/compensate them. Together with the @ref{vidstabdetect}
10783 filter this can be used to deshake videos. See also
10784 @url{http://public.hronopik.de/vid.stab}. It is important to also use
10785 the @ref{unsharp} filter, see below.
10787 To enable compilation of this filter you need to configure FFmpeg with
10788 @code{--enable-libvidstab}.
10790 @subsection Options
10794 Set path to the file used to read the transforms. Default value is
10795 @file{transforms.trf}.
10798 Set the number of frames (value*2 + 1) used for lowpass filtering the
10799 camera movements. Default value is 10.
10801 For example a number of 10 means that 21 frames are used (10 in the
10802 past and 10 in the future) to smoothen the motion in the video. A
10803 larger value leads to a smoother video, but limits the acceleration of
10804 the camera (pan/tilt movements). 0 is a special case where a static
10805 camera is simulated.
10808 Set the camera path optimization algorithm.
10810 Accepted values are:
10813 gaussian kernel low-pass filter on camera motion (default)
10815 averaging on transformations
10819 Set maximal number of pixels to translate frames. Default value is -1,
10823 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
10824 value is -1, meaning no limit.
10827 Specify how to deal with borders that may be visible due to movement
10830 Available values are:
10833 keep image information from previous frame (default)
10835 fill the border black
10839 Invert transforms if set to 1. Default value is 0.
10842 Consider transforms as relative to previous frame if set to 1,
10843 absolute if set to 0. Default value is 0.
10846 Set percentage to zoom. A positive value will result in a zoom-in
10847 effect, a negative value in a zoom-out effect. Default value is 0 (no
10851 Set optimal zooming to avoid borders.
10853 Accepted values are:
10858 optimal static zoom value is determined (only very strong movements
10859 will lead to visible borders) (default)
10861 optimal adaptive zoom value is determined (no borders will be
10862 visible), see @option{zoomspeed}
10865 Note that the value given at zoom is added to the one calculated here.
10868 Set percent to zoom maximally each frame (enabled when
10869 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
10873 Specify type of interpolation.
10875 Available values are:
10880 linear only horizontal
10882 linear in both directions (default)
10884 cubic in both directions (slow)
10888 Enable virtual tripod mode if set to 1, which is equivalent to
10889 @code{relative=0:smoothing=0}. Default value is 0.
10891 Use also @code{tripod} option of @ref{vidstabdetect}.
10894 Increase log verbosity if set to 1. Also the detected global motions
10895 are written to the temporary file @file{global_motions.trf}. Default
10899 @subsection Examples
10903 Use @command{ffmpeg} for a typical stabilization with default values:
10905 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
10908 Note the use of the @ref{unsharp} filter which is always recommended.
10911 Zoom in a bit more and load transform data from a given file:
10913 vidstabtransform=zoom=5:input="mytransforms.trf"
10917 Smoothen the video even more:
10919 vidstabtransform=smoothing=30
10925 Flip the input video vertically.
10927 For example, to vertically flip a video with @command{ffmpeg}:
10929 ffmpeg -i in.avi -vf "vflip" out.avi
10935 Make or reverse a natural vignetting effect.
10937 The filter accepts the following options:
10941 Set lens angle expression as a number of radians.
10943 The value is clipped in the @code{[0,PI/2]} range.
10945 Default value: @code{"PI/5"}
10949 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
10953 Set forward/backward mode.
10955 Available modes are:
10958 The larger the distance from the central point, the darker the image becomes.
10961 The larger the distance from the central point, the brighter the image becomes.
10962 This can be used to reverse a vignette effect, though there is no automatic
10963 detection to extract the lens @option{angle} and other settings (yet). It can
10964 also be used to create a burning effect.
10967 Default value is @samp{forward}.
10970 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
10972 It accepts the following values:
10975 Evaluate expressions only once during the filter initialization.
10978 Evaluate expressions for each incoming frame. This is way slower than the
10979 @samp{init} mode since it requires all the scalers to be re-computed, but it
10980 allows advanced dynamic expressions.
10983 Default value is @samp{init}.
10986 Set dithering to reduce the circular banding effects. Default is @code{1}
10990 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
10991 Setting this value to the SAR of the input will make a rectangular vignetting
10992 following the dimensions of the video.
10994 Default is @code{1/1}.
10997 @subsection Expressions
10999 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
11000 following parameters.
11005 input width and height
11008 the number of input frame, starting from 0
11011 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
11012 @var{TB} units, NAN if undefined
11015 frame rate of the input video, NAN if the input frame rate is unknown
11018 the PTS (Presentation TimeStamp) of the filtered video frame,
11019 expressed in seconds, NAN if undefined
11022 time base of the input video
11026 @subsection Examples
11030 Apply simple strong vignetting effect:
11036 Make a flickering vignetting:
11038 vignette='PI/4+random(1)*PI/50':eval=frame
11044 Stack input videos vertically.
11046 All streams must be of same pixel format and of same width.
11048 Note that this filter is faster than using @ref{overlay} and @ref{pad} filter
11049 to create same output.
11051 The filter accept the following option:
11055 Set number of input streams. Default is 2.
11060 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
11061 Deinterlacing Filter").
11063 Based on the process described by Martin Weston for BBC R&D, and
11064 implemented based on the de-interlace algorithm written by Jim
11065 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
11066 uses filter coefficients calculated by BBC R&D.
11068 There are two sets of filter coefficients, so called "simple":
11069 and "complex". Which set of filter coefficients is used can
11070 be set by passing an optional parameter:
11074 Set the interlacing filter coefficients. Accepts one of the following values:
11078 Simple filter coefficient set.
11080 More-complex filter coefficient set.
11082 Default value is @samp{complex}.
11085 Specify which frames to deinterlace. Accept one of the following values:
11089 Deinterlace all frames,
11091 Only deinterlace frames marked as interlaced.
11094 Default value is @samp{all}.
11098 Video waveform monitor.
11100 The waveform monitor plots color component intensity. By default luminance
11101 only. Each column of the waveform corresponds to a column of pixels in the
11104 It accepts the following options:
11108 Can be either @code{row}, or @code{column}. Default is @code{column}.
11109 In row mode, the graph on the left side represents color component value 0 and
11110 the right side represents value = 255. In column mode, the top side represents
11111 color component value = 0 and bottom side represents value = 255.
11114 Set intensity. Smaller values are useful to find out how many values of the same
11115 luminance are distributed across input rows/columns.
11116 Default value is @code{0.04}. Allowed range is [0, 1].
11119 Set mirroring mode. @code{0} means unmirrored, @code{1} means mirrored.
11120 In mirrored mode, higher values will be represented on the left
11121 side for @code{row} mode and at the top for @code{column} mode. Default is
11122 @code{1} (mirrored).
11126 It accepts the following values:
11129 Presents information identical to that in the @code{parade}, except
11130 that the graphs representing color components are superimposed directly
11133 This display mode makes it easier to spot relative differences or similarities
11134 in overlapping areas of the color components that are supposed to be identical,
11135 such as neutral whites, grays, or blacks.
11138 Display separate graph for the color components side by side in
11139 @code{row} mode or one below the other in @code{column} mode.
11141 Using this display mode makes it easy to spot color casts in the highlights
11142 and shadows of an image, by comparing the contours of the top and the bottom
11143 graphs of each waveform. Since whites, grays, and blacks are characterized
11144 by exactly equal amounts of red, green, and blue, neutral areas of the picture
11145 should display three waveforms of roughly equal width/height. If not, the
11146 correction is easy to perform by making level adjustments the three waveforms.
11148 Default is @code{parade}.
11150 @item components, c
11151 Set which color components to display. Default is 1, which means only luminance
11152 or red color component if input is in RGB colorspace. If is set for example to
11153 7 it will display all 3 (if) available color components.
11158 No envelope, this is default.
11161 Instant envelope, minimum and maximum values presented in graph will be easily
11162 visible even with small @code{step} value.
11165 Hold minimum and maximum values presented in graph across time. This way you
11166 can still spot out of range values without constantly looking at waveforms.
11169 Peak and instant envelope combined together.
11175 No filtering, this is default.
11178 Luma and chroma combined together.
11181 Similar as above, but shows difference between blue and red chroma.
11184 Displays only chroma.
11187 Similar as above, but shows difference between blue and red chroma.
11190 Displays actual color value on waveform.
11195 Apply the xBR high-quality magnification filter which is designed for pixel
11196 art. It follows a set of edge-detection rules, see
11197 @url{http://www.libretro.com/forums/viewtopic.php?f=6&t=134}.
11199 It accepts the following option:
11203 Set the scaling dimension: @code{2} for @code{2xBR}, @code{3} for
11204 @code{3xBR} and @code{4} for @code{4xBR}.
11205 Default is @code{3}.
11211 Deinterlace the input video ("yadif" means "yet another deinterlacing
11214 It accepts the following parameters:
11220 The interlacing mode to adopt. It accepts one of the following values:
11223 @item 0, send_frame
11224 Output one frame for each frame.
11225 @item 1, send_field
11226 Output one frame for each field.
11227 @item 2, send_frame_nospatial
11228 Like @code{send_frame}, but it skips the spatial interlacing check.
11229 @item 3, send_field_nospatial
11230 Like @code{send_field}, but it skips the spatial interlacing check.
11233 The default value is @code{send_frame}.
11236 The picture field parity assumed for the input interlaced video. It accepts one
11237 of the following values:
11241 Assume the top field is first.
11243 Assume the bottom field is first.
11245 Enable automatic detection of field parity.
11248 The default value is @code{auto}.
11249 If the interlacing is unknown or the decoder does not export this information,
11250 top field first will be assumed.
11253 Specify which frames to deinterlace. Accept one of the following
11258 Deinterlace all frames.
11259 @item 1, interlaced
11260 Only deinterlace frames marked as interlaced.
11263 The default value is @code{all}.
11268 Apply Zoom & Pan effect.
11270 This filter accepts the following options:
11274 Set the zoom expression. Default is 1.
11278 Set the x and y expression. Default is 0.
11281 Set the duration expression in number of frames.
11282 This sets for how many number of frames effect will last for
11283 single input image.
11286 Set the output image size, default is 'hd720'.
11289 Each expression can contain the following constants:
11308 Output frame count.
11312 Last calculated 'x' and 'y' position from 'x' and 'y' expression
11313 for current input frame.
11317 'x' and 'y' of last output frame of previous input frame or 0 when there was
11318 not yet such frame (first input frame).
11321 Last calculated zoom from 'z' expression for current input frame.
11324 Last calculated zoom of last output frame of previous input frame.
11327 Number of output frames for current input frame. Calculated from 'd' expression
11328 for each input frame.
11331 number of output frames created for previous input frame
11334 Rational number: input width / input height
11337 sample aspect ratio
11340 display aspect ratio
11344 @subsection Examples
11348 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
11350 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
11354 Zoom-in up to 1.5 and pan always at center of picture:
11356 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'
11360 @c man end VIDEO FILTERS
11362 @chapter Video Sources
11363 @c man begin VIDEO SOURCES
11365 Below is a description of the currently available video sources.
11369 Buffer video frames, and make them available to the filter chain.
11371 This source is mainly intended for a programmatic use, in particular
11372 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
11374 It accepts the following parameters:
11379 Specify the size (width and height) of the buffered video frames. For the
11380 syntax of this option, check the
11381 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11384 The input video width.
11387 The input video height.
11390 A string representing the pixel format of the buffered video frames.
11391 It may be a number corresponding to a pixel format, or a pixel format
11395 Specify the timebase assumed by the timestamps of the buffered frames.
11398 Specify the frame rate expected for the video stream.
11400 @item pixel_aspect, sar
11401 The sample (pixel) aspect ratio of the input video.
11404 Specify the optional parameters to be used for the scale filter which
11405 is automatically inserted when an input change is detected in the
11406 input size or format.
11411 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
11414 will instruct the source to accept video frames with size 320x240 and
11415 with format "yuv410p", assuming 1/24 as the timestamps timebase and
11416 square pixels (1:1 sample aspect ratio).
11417 Since the pixel format with name "yuv410p" corresponds to the number 6
11418 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
11419 this example corresponds to:
11421 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
11424 Alternatively, the options can be specified as a flat string, but this
11425 syntax is deprecated:
11427 @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}]
11431 Create a pattern generated by an elementary cellular automaton.
11433 The initial state of the cellular automaton can be defined through the
11434 @option{filename}, and @option{pattern} options. If such options are
11435 not specified an initial state is created randomly.
11437 At each new frame a new row in the video is filled with the result of
11438 the cellular automaton next generation. The behavior when the whole
11439 frame is filled is defined by the @option{scroll} option.
11441 This source accepts the following options:
11445 Read the initial cellular automaton state, i.e. the starting row, from
11446 the specified file.
11447 In the file, each non-whitespace character is considered an alive
11448 cell, a newline will terminate the row, and further characters in the
11449 file will be ignored.
11452 Read the initial cellular automaton state, i.e. the starting row, from
11453 the specified string.
11455 Each non-whitespace character in the string is considered an alive
11456 cell, a newline will terminate the row, and further characters in the
11457 string will be ignored.
11460 Set the video rate, that is the number of frames generated per second.
11463 @item random_fill_ratio, ratio
11464 Set the random fill ratio for the initial cellular automaton row. It
11465 is a floating point number value ranging from 0 to 1, defaults to
11468 This option is ignored when a file or a pattern is specified.
11470 @item random_seed, seed
11471 Set the seed for filling randomly the initial row, must be an integer
11472 included between 0 and UINT32_MAX. If not specified, or if explicitly
11473 set to -1, the filter will try to use a good random seed on a best
11477 Set the cellular automaton rule, it is a number ranging from 0 to 255.
11478 Default value is 110.
11481 Set the size of the output video. For the syntax of this option, check the
11482 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11484 If @option{filename} or @option{pattern} is specified, the size is set
11485 by default to the width of the specified initial state row, and the
11486 height is set to @var{width} * PHI.
11488 If @option{size} is set, it must contain the width of the specified
11489 pattern string, and the specified pattern will be centered in the
11492 If a filename or a pattern string is not specified, the size value
11493 defaults to "320x518" (used for a randomly generated initial state).
11496 If set to 1, scroll the output upward when all the rows in the output
11497 have been already filled. If set to 0, the new generated row will be
11498 written over the top row just after the bottom row is filled.
11501 @item start_full, full
11502 If set to 1, completely fill the output with generated rows before
11503 outputting the first frame.
11504 This is the default behavior, for disabling set the value to 0.
11507 If set to 1, stitch the left and right row edges together.
11508 This is the default behavior, for disabling set the value to 0.
11511 @subsection Examples
11515 Read the initial state from @file{pattern}, and specify an output of
11518 cellauto=f=pattern:s=200x400
11522 Generate a random initial row with a width of 200 cells, with a fill
11525 cellauto=ratio=2/3:s=200x200
11529 Create a pattern generated by rule 18 starting by a single alive cell
11530 centered on an initial row with width 100:
11532 cellauto=p=@@:s=100x400:full=0:rule=18
11536 Specify a more elaborated initial pattern:
11538 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
11543 @section mandelbrot
11545 Generate a Mandelbrot set fractal, and progressively zoom towards the
11546 point specified with @var{start_x} and @var{start_y}.
11548 This source accepts the following options:
11553 Set the terminal pts value. Default value is 400.
11556 Set the terminal scale value.
11557 Must be a floating point value. Default value is 0.3.
11560 Set the inner coloring mode, that is the algorithm used to draw the
11561 Mandelbrot fractal internal region.
11563 It shall assume one of the following values:
11568 Show time until convergence.
11570 Set color based on point closest to the origin of the iterations.
11575 Default value is @var{mincol}.
11578 Set the bailout value. Default value is 10.0.
11581 Set the maximum of iterations performed by the rendering
11582 algorithm. Default value is 7189.
11585 Set outer coloring mode.
11586 It shall assume one of following values:
11588 @item iteration_count
11589 Set iteration cound mode.
11590 @item normalized_iteration_count
11591 set normalized iteration count mode.
11593 Default value is @var{normalized_iteration_count}.
11596 Set frame rate, expressed as number of frames per second. Default
11600 Set frame size. For the syntax of this option, check the "Video
11601 size" section in the ffmpeg-utils manual. Default value is "640x480".
11604 Set the initial scale value. Default value is 3.0.
11607 Set the initial x position. Must be a floating point value between
11608 -100 and 100. Default value is -0.743643887037158704752191506114774.
11611 Set the initial y position. Must be a floating point value between
11612 -100 and 100. Default value is -0.131825904205311970493132056385139.
11617 Generate various test patterns, as generated by the MPlayer test filter.
11619 The size of the generated video is fixed, and is 256x256.
11620 This source is useful in particular for testing encoding features.
11622 This source accepts the following options:
11627 Specify the frame rate of the sourced video, as the number of frames
11628 generated per second. It has to be a string in the format
11629 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
11630 number or a valid video frame rate abbreviation. The default value is
11634 Set the duration of the sourced video. See
11635 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
11636 for the accepted syntax.
11638 If not specified, or the expressed duration is negative, the video is
11639 supposed to be generated forever.
11643 Set the number or the name of the test to perform. Supported tests are:
11659 Default value is "all", which will cycle through the list of all tests.
11664 mptestsrc=t=dc_luma
11667 will generate a "dc_luma" test pattern.
11669 @section frei0r_src
11671 Provide a frei0r source.
11673 To enable compilation of this filter you need to install the frei0r
11674 header and configure FFmpeg with @code{--enable-frei0r}.
11676 This source accepts the following parameters:
11681 The size of the video to generate. For the syntax of this option, check the
11682 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11685 The framerate of the generated video. It may be a string of the form
11686 @var{num}/@var{den} or a frame rate abbreviation.
11689 The name to the frei0r source to load. For more information regarding frei0r and
11690 how to set the parameters, read the @ref{frei0r} section in the video filters
11693 @item filter_params
11694 A '|'-separated list of parameters to pass to the frei0r source.
11698 For example, to generate a frei0r partik0l source with size 200x200
11699 and frame rate 10 which is overlaid on the overlay filter main input:
11701 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
11706 Generate a life pattern.
11708 This source is based on a generalization of John Conway's life game.
11710 The sourced input represents a life grid, each pixel represents a cell
11711 which can be in one of two possible states, alive or dead. Every cell
11712 interacts with its eight neighbours, which are the cells that are
11713 horizontally, vertically, or diagonally adjacent.
11715 At each interaction the grid evolves according to the adopted rule,
11716 which specifies the number of neighbor alive cells which will make a
11717 cell stay alive or born. The @option{rule} option allows one to specify
11720 This source accepts the following options:
11724 Set the file from which to read the initial grid state. In the file,
11725 each non-whitespace character is considered an alive cell, and newline
11726 is used to delimit the end of each row.
11728 If this option is not specified, the initial grid is generated
11732 Set the video rate, that is the number of frames generated per second.
11735 @item random_fill_ratio, ratio
11736 Set the random fill ratio for the initial random grid. It is a
11737 floating point number value ranging from 0 to 1, defaults to 1/PHI.
11738 It is ignored when a file is specified.
11740 @item random_seed, seed
11741 Set the seed for filling the initial random grid, must be an integer
11742 included between 0 and UINT32_MAX. If not specified, or if explicitly
11743 set to -1, the filter will try to use a good random seed on a best
11749 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
11750 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
11751 @var{NS} specifies the number of alive neighbor cells which make a
11752 live cell stay alive, and @var{NB} the number of alive neighbor cells
11753 which make a dead cell to become alive (i.e. to "born").
11754 "s" and "b" can be used in place of "S" and "B", respectively.
11756 Alternatively a rule can be specified by an 18-bits integer. The 9
11757 high order bits are used to encode the next cell state if it is alive
11758 for each number of neighbor alive cells, the low order bits specify
11759 the rule for "borning" new cells. Higher order bits encode for an
11760 higher number of neighbor cells.
11761 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
11762 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
11764 Default value is "S23/B3", which is the original Conway's game of life
11765 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
11766 cells, and will born a new cell if there are three alive cells around
11770 Set the size of the output video. For the syntax of this option, check the
11771 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11773 If @option{filename} is specified, the size is set by default to the
11774 same size of the input file. If @option{size} is set, it must contain
11775 the size specified in the input file, and the initial grid defined in
11776 that file is centered in the larger resulting area.
11778 If a filename is not specified, the size value defaults to "320x240"
11779 (used for a randomly generated initial grid).
11782 If set to 1, stitch the left and right grid edges together, and the
11783 top and bottom edges also. Defaults to 1.
11786 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
11787 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
11788 value from 0 to 255.
11791 Set the color of living (or new born) cells.
11794 Set the color of dead cells. If @option{mold} is set, this is the first color
11795 used to represent a dead cell.
11798 Set mold color, for definitely dead and moldy cells.
11800 For the syntax of these 3 color options, check the "Color" section in the
11801 ffmpeg-utils manual.
11804 @subsection Examples
11808 Read a grid from @file{pattern}, and center it on a grid of size
11811 life=f=pattern:s=300x300
11815 Generate a random grid of size 200x200, with a fill ratio of 2/3:
11817 life=ratio=2/3:s=200x200
11821 Specify a custom rule for evolving a randomly generated grid:
11827 Full example with slow death effect (mold) using @command{ffplay}:
11829 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
11836 @anchor{haldclutsrc}
11838 @anchor{rgbtestsrc}
11840 @anchor{smptehdbars}
11842 @section allrgb, allyuv, color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
11844 The @code{allrgb} source returns frames of size 4096x4096 of all rgb colors.
11846 The @code{allyuv} source returns frames of size 4096x4096 of all yuv colors.
11848 The @code{color} source provides an uniformly colored input.
11850 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
11851 @ref{haldclut} filter.
11853 The @code{nullsrc} source returns unprocessed video frames. It is
11854 mainly useful to be employed in analysis / debugging tools, or as the
11855 source for filters which ignore the input data.
11857 The @code{rgbtestsrc} source generates an RGB test pattern useful for
11858 detecting RGB vs BGR issues. You should see a red, green and blue
11859 stripe from top to bottom.
11861 The @code{smptebars} source generates a color bars pattern, based on
11862 the SMPTE Engineering Guideline EG 1-1990.
11864 The @code{smptehdbars} source generates a color bars pattern, based on
11865 the SMPTE RP 219-2002.
11867 The @code{testsrc} source generates a test video pattern, showing a
11868 color pattern, a scrolling gradient and a timestamp. This is mainly
11869 intended for testing purposes.
11871 The sources accept the following parameters:
11876 Specify the color of the source, only available in the @code{color}
11877 source. For the syntax of this option, check the "Color" section in the
11878 ffmpeg-utils manual.
11881 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
11882 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
11883 pixels to be used as identity matrix for 3D lookup tables. Each component is
11884 coded on a @code{1/(N*N)} scale.
11887 Specify the size of the sourced video. For the syntax of this option, check the
11888 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11889 The default value is @code{320x240}.
11891 This option is not available with the @code{haldclutsrc} filter.
11894 Specify the frame rate of the sourced video, as the number of frames
11895 generated per second. It has to be a string in the format
11896 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
11897 number or a valid video frame rate abbreviation. The default value is
11901 Set the sample aspect ratio of the sourced video.
11904 Set the duration of the sourced video. See
11905 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
11906 for the accepted syntax.
11908 If not specified, or the expressed duration is negative, the video is
11909 supposed to be generated forever.
11912 Set the number of decimals to show in the timestamp, only available in the
11913 @code{testsrc} source.
11915 The displayed timestamp value will correspond to the original
11916 timestamp value multiplied by the power of 10 of the specified
11917 value. Default value is 0.
11920 For example the following:
11922 testsrc=duration=5.3:size=qcif:rate=10
11925 will generate a video with a duration of 5.3 seconds, with size
11926 176x144 and a frame rate of 10 frames per second.
11928 The following graph description will generate a red source
11929 with an opacity of 0.2, with size "qcif" and a frame rate of 10
11932 color=c=red@@0.2:s=qcif:r=10
11935 If the input content is to be ignored, @code{nullsrc} can be used. The
11936 following command generates noise in the luminance plane by employing
11937 the @code{geq} filter:
11939 nullsrc=s=256x256, geq=random(1)*255:128:128
11942 @subsection Commands
11944 The @code{color} source supports the following commands:
11948 Set the color of the created image. Accepts the same syntax of the
11949 corresponding @option{color} option.
11952 @c man end VIDEO SOURCES
11954 @chapter Video Sinks
11955 @c man begin VIDEO SINKS
11957 Below is a description of the currently available video sinks.
11959 @section buffersink
11961 Buffer video frames, and make them available to the end of the filter
11964 This sink is mainly intended for programmatic use, in particular
11965 through the interface defined in @file{libavfilter/buffersink.h}
11966 or the options system.
11968 It accepts a pointer to an AVBufferSinkContext structure, which
11969 defines the incoming buffers' formats, to be passed as the opaque
11970 parameter to @code{avfilter_init_filter} for initialization.
11974 Null video sink: do absolutely nothing with the input video. It is
11975 mainly useful as a template and for use in analysis / debugging
11978 @c man end VIDEO SINKS
11980 @chapter Multimedia Filters
11981 @c man begin MULTIMEDIA FILTERS
11983 Below is a description of the currently available multimedia filters.
11985 @section aphasemeter
11987 Convert input audio to a video output, displaying the audio phase.
11989 The filter accepts the following options:
11993 Set the output frame rate. Default value is @code{25}.
11996 Set the video size for the output. For the syntax of this option, check the
11997 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
11998 Default value is @code{800x400}.
12003 Specify the red, green, blue contrast. Default values are @code{2},
12004 @code{7} and @code{1}.
12005 Allowed range is @code{[0, 255]}.
12008 Set color which will be used for drawing median phase. If color is
12009 @code{none} which is default, no median phase value will be drawn.
12012 The filter also exports the frame metadata @code{lavfi.aphasemeter.phase} which
12013 represents mean phase of current audio frame. Value is in range @code{[-1, 1]}.
12014 The @code{-1} means left and right channels are completely out of phase and
12015 @code{1} means channels are in phase.
12017 @section avectorscope
12019 Convert input audio to a video output, representing the audio vector
12022 The filter is used to measure the difference between channels of stereo
12023 audio stream. A monoaural signal, consisting of identical left and right
12024 signal, results in straight vertical line. Any stereo separation is visible
12025 as a deviation from this line, creating a Lissajous figure.
12026 If the straight (or deviation from it) but horizontal line appears this
12027 indicates that the left and right channels are out of phase.
12029 The filter accepts the following options:
12033 Set the vectorscope mode.
12035 Available values are:
12038 Lissajous rotated by 45 degrees.
12041 Same as above but not rotated.
12044 Shape resembling half of circle.
12047 Default value is @samp{lissajous}.
12050 Set the video size for the output. For the syntax of this option, check the
12051 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12052 Default value is @code{400x400}.
12055 Set the output frame rate. Default value is @code{25}.
12061 Specify the red, green, blue and alpha contrast. Default values are @code{40},
12062 @code{160}, @code{80} and @code{255}.
12063 Allowed range is @code{[0, 255]}.
12069 Specify the red, green, blue and alpha fade. Default values are @code{15},
12070 @code{10}, @code{5} and @code{5}.
12071 Allowed range is @code{[0, 255]}.
12074 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
12077 @subsection Examples
12081 Complete example using @command{ffplay}:
12083 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
12084 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
12090 Concatenate audio and video streams, joining them together one after the
12093 The filter works on segments of synchronized video and audio streams. All
12094 segments must have the same number of streams of each type, and that will
12095 also be the number of streams at output.
12097 The filter accepts the following options:
12102 Set the number of segments. Default is 2.
12105 Set the number of output video streams, that is also the number of video
12106 streams in each segment. Default is 1.
12109 Set the number of output audio streams, that is also the number of audio
12110 streams in each segment. Default is 0.
12113 Activate unsafe mode: do not fail if segments have a different format.
12117 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
12118 @var{a} audio outputs.
12120 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
12121 segment, in the same order as the outputs, then the inputs for the second
12124 Related streams do not always have exactly the same duration, for various
12125 reasons including codec frame size or sloppy authoring. For that reason,
12126 related synchronized streams (e.g. a video and its audio track) should be
12127 concatenated at once. The concat filter will use the duration of the longest
12128 stream in each segment (except the last one), and if necessary pad shorter
12129 audio streams with silence.
12131 For this filter to work correctly, all segments must start at timestamp 0.
12133 All corresponding streams must have the same parameters in all segments; the
12134 filtering system will automatically select a common pixel format for video
12135 streams, and a common sample format, sample rate and channel layout for
12136 audio streams, but other settings, such as resolution, must be converted
12137 explicitly by the user.
12139 Different frame rates are acceptable but will result in variable frame rate
12140 at output; be sure to configure the output file to handle it.
12142 @subsection Examples
12146 Concatenate an opening, an episode and an ending, all in bilingual version
12147 (video in stream 0, audio in streams 1 and 2):
12149 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
12150 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
12151 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
12152 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
12156 Concatenate two parts, handling audio and video separately, using the
12157 (a)movie sources, and adjusting the resolution:
12159 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
12160 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
12161 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
12163 Note that a desync will happen at the stitch if the audio and video streams
12164 do not have exactly the same duration in the first file.
12171 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
12172 it unchanged. By default, it logs a message at a frequency of 10Hz with the
12173 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
12174 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
12176 The filter also has a video output (see the @var{video} option) with a real
12177 time graph to observe the loudness evolution. The graphic contains the logged
12178 message mentioned above, so it is not printed anymore when this option is set,
12179 unless the verbose logging is set. The main graphing area contains the
12180 short-term loudness (3 seconds of analysis), and the gauge on the right is for
12181 the momentary loudness (400 milliseconds).
12183 More information about the Loudness Recommendation EBU R128 on
12184 @url{http://tech.ebu.ch/loudness}.
12186 The filter accepts the following options:
12191 Activate the video output. The audio stream is passed unchanged whether this
12192 option is set or no. The video stream will be the first output stream if
12193 activated. Default is @code{0}.
12196 Set the video size. This option is for video only. For the syntax of this
12198 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
12199 Default and minimum resolution is @code{640x480}.
12202 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
12203 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
12204 other integer value between this range is allowed.
12207 Set metadata injection. If set to @code{1}, the audio input will be segmented
12208 into 100ms output frames, each of them containing various loudness information
12209 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
12211 Default is @code{0}.
12214 Force the frame logging level.
12216 Available values are:
12219 information logging level
12221 verbose logging level
12224 By default, the logging level is set to @var{info}. If the @option{video} or
12225 the @option{metadata} options are set, it switches to @var{verbose}.
12230 Available modes can be cumulated (the option is a @code{flag} type). Possible
12234 Disable any peak mode (default).
12236 Enable sample-peak mode.
12238 Simple peak mode looking for the higher sample value. It logs a message
12239 for sample-peak (identified by @code{SPK}).
12241 Enable true-peak mode.
12243 If enabled, the peak lookup is done on an over-sampled version of the input
12244 stream for better peak accuracy. It logs a message for true-peak.
12245 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
12246 This mode requires a build with @code{libswresample}.
12251 @subsection Examples
12255 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
12257 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
12261 Run an analysis with @command{ffmpeg}:
12263 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
12267 @section interleave, ainterleave
12269 Temporally interleave frames from several inputs.
12271 @code{interleave} works with video inputs, @code{ainterleave} with audio.
12273 These filters read frames from several inputs and send the oldest
12274 queued frame to the output.
12276 Input streams must have a well defined, monotonically increasing frame
12279 In order to submit one frame to output, these filters need to enqueue
12280 at least one frame for each input, so they cannot work in case one
12281 input is not yet terminated and will not receive incoming frames.
12283 For example consider the case when one input is a @code{select} filter
12284 which always drop input frames. The @code{interleave} filter will keep
12285 reading from that input, but it will never be able to send new frames
12286 to output until the input will send an end-of-stream signal.
12288 Also, depending on inputs synchronization, the filters will drop
12289 frames in case one input receives more frames than the other ones, and
12290 the queue is already filled.
12292 These filters accept the following options:
12296 Set the number of different inputs, it is 2 by default.
12299 @subsection Examples
12303 Interleave frames belonging to different streams using @command{ffmpeg}:
12305 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
12309 Add flickering blur effect:
12311 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
12315 @section perms, aperms
12317 Set read/write permissions for the output frames.
12319 These filters are mainly aimed at developers to test direct path in the
12320 following filter in the filtergraph.
12322 The filters accept the following options:
12326 Select the permissions mode.
12328 It accepts the following values:
12331 Do nothing. This is the default.
12333 Set all the output frames read-only.
12335 Set all the output frames directly writable.
12337 Make the frame read-only if writable, and writable if read-only.
12339 Set each output frame read-only or writable randomly.
12343 Set the seed for the @var{random} mode, must be an integer included between
12344 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
12345 @code{-1}, the filter will try to use a good random seed on a best effort
12349 Note: in case of auto-inserted filter between the permission filter and the
12350 following one, the permission might not be received as expected in that
12351 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
12352 perms/aperms filter can avoid this problem.
12354 @section select, aselect
12356 Select frames to pass in output.
12358 This filter accepts the following options:
12363 Set expression, which is evaluated for each input frame.
12365 If the expression is evaluated to zero, the frame is discarded.
12367 If the evaluation result is negative or NaN, the frame is sent to the
12368 first output; otherwise it is sent to the output with index
12369 @code{ceil(val)-1}, assuming that the input index starts from 0.
12371 For example a value of @code{1.2} corresponds to the output with index
12372 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
12375 Set the number of outputs. The output to which to send the selected
12376 frame is based on the result of the evaluation. Default value is 1.
12379 The expression can contain the following constants:
12383 The (sequential) number of the filtered frame, starting from 0.
12386 The (sequential) number of the selected frame, starting from 0.
12388 @item prev_selected_n
12389 The sequential number of the last selected frame. It's NAN if undefined.
12392 The timebase of the input timestamps.
12395 The PTS (Presentation TimeStamp) of the filtered video frame,
12396 expressed in @var{TB} units. It's NAN if undefined.
12399 The PTS of the filtered video frame,
12400 expressed in seconds. It's NAN if undefined.
12403 The PTS of the previously filtered video frame. It's NAN if undefined.
12405 @item prev_selected_pts
12406 The PTS of the last previously filtered video frame. It's NAN if undefined.
12408 @item prev_selected_t
12409 The PTS of the last previously selected video frame. It's NAN if undefined.
12412 The PTS of the first video frame in the video. It's NAN if undefined.
12415 The time of the first video frame in the video. It's NAN if undefined.
12417 @item pict_type @emph{(video only)}
12418 The type of the filtered frame. It can assume one of the following
12430 @item interlace_type @emph{(video only)}
12431 The frame interlace type. It can assume one of the following values:
12434 The frame is progressive (not interlaced).
12436 The frame is top-field-first.
12438 The frame is bottom-field-first.
12441 @item consumed_sample_n @emph{(audio only)}
12442 the number of selected samples before the current frame
12444 @item samples_n @emph{(audio only)}
12445 the number of samples in the current frame
12447 @item sample_rate @emph{(audio only)}
12448 the input sample rate
12451 This is 1 if the filtered frame is a key-frame, 0 otherwise.
12454 the position in the file of the filtered frame, -1 if the information
12455 is not available (e.g. for synthetic video)
12457 @item scene @emph{(video only)}
12458 value between 0 and 1 to indicate a new scene; a low value reflects a low
12459 probability for the current frame to introduce a new scene, while a higher
12460 value means the current frame is more likely to be one (see the example below)
12464 The default value of the select expression is "1".
12466 @subsection Examples
12470 Select all frames in input:
12475 The example above is the same as:
12487 Select only I-frames:
12489 select='eq(pict_type\,I)'
12493 Select one frame every 100:
12495 select='not(mod(n\,100))'
12499 Select only frames contained in the 10-20 time interval:
12501 select=between(t\,10\,20)
12505 Select only I frames contained in the 10-20 time interval:
12507 select=between(t\,10\,20)*eq(pict_type\,I)
12511 Select frames with a minimum distance of 10 seconds:
12513 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
12517 Use aselect to select only audio frames with samples number > 100:
12519 aselect='gt(samples_n\,100)'
12523 Create a mosaic of the first scenes:
12525 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
12528 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
12532 Send even and odd frames to separate outputs, and compose them:
12534 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
12538 @section sendcmd, asendcmd
12540 Send commands to filters in the filtergraph.
12542 These filters read commands to be sent to other filters in the
12545 @code{sendcmd} must be inserted between two video filters,
12546 @code{asendcmd} must be inserted between two audio filters, but apart
12547 from that they act the same way.
12549 The specification of commands can be provided in the filter arguments
12550 with the @var{commands} option, or in a file specified by the
12551 @var{filename} option.
12553 These filters accept the following options:
12556 Set the commands to be read and sent to the other filters.
12558 Set the filename of the commands to be read and sent to the other
12562 @subsection Commands syntax
12564 A commands description consists of a sequence of interval
12565 specifications, comprising a list of commands to be executed when a
12566 particular event related to that interval occurs. The occurring event
12567 is typically the current frame time entering or leaving a given time
12570 An interval is specified by the following syntax:
12572 @var{START}[-@var{END}] @var{COMMANDS};
12575 The time interval is specified by the @var{START} and @var{END} times.
12576 @var{END} is optional and defaults to the maximum time.
12578 The current frame time is considered within the specified interval if
12579 it is included in the interval [@var{START}, @var{END}), that is when
12580 the time is greater or equal to @var{START} and is lesser than
12583 @var{COMMANDS} consists of a sequence of one or more command
12584 specifications, separated by ",", relating to that interval. The
12585 syntax of a command specification is given by:
12587 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
12590 @var{FLAGS} is optional and specifies the type of events relating to
12591 the time interval which enable sending the specified command, and must
12592 be a non-null sequence of identifier flags separated by "+" or "|" and
12593 enclosed between "[" and "]".
12595 The following flags are recognized:
12598 The command is sent when the current frame timestamp enters the
12599 specified interval. In other words, the command is sent when the
12600 previous frame timestamp was not in the given interval, and the
12604 The command is sent when the current frame timestamp leaves the
12605 specified interval. In other words, the command is sent when the
12606 previous frame timestamp was in the given interval, and the
12610 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
12613 @var{TARGET} specifies the target of the command, usually the name of
12614 the filter class or a specific filter instance name.
12616 @var{COMMAND} specifies the name of the command for the target filter.
12618 @var{ARG} is optional and specifies the optional list of argument for
12619 the given @var{COMMAND}.
12621 Between one interval specification and another, whitespaces, or
12622 sequences of characters starting with @code{#} until the end of line,
12623 are ignored and can be used to annotate comments.
12625 A simplified BNF description of the commands specification syntax
12628 @var{COMMAND_FLAG} ::= "enter" | "leave"
12629 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
12630 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
12631 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
12632 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
12633 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
12636 @subsection Examples
12640 Specify audio tempo change at second 4:
12642 asendcmd=c='4.0 atempo tempo 1.5',atempo
12646 Specify a list of drawtext and hue commands in a file.
12648 # show text in the interval 5-10
12649 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
12650 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
12652 # desaturate the image in the interval 15-20
12653 15.0-20.0 [enter] hue s 0,
12654 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
12656 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
12658 # apply an exponential saturation fade-out effect, starting from time 25
12659 25 [enter] hue s exp(25-t)
12662 A filtergraph allowing to read and process the above command list
12663 stored in a file @file{test.cmd}, can be specified with:
12665 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
12670 @section setpts, asetpts
12672 Change the PTS (presentation timestamp) of the input frames.
12674 @code{setpts} works on video frames, @code{asetpts} on audio frames.
12676 This filter accepts the following options:
12681 The expression which is evaluated for each frame to construct its timestamp.
12685 The expression is evaluated through the eval API and can contain the following
12690 frame rate, only defined for constant frame-rate video
12693 The presentation timestamp in input
12696 The count of the input frame for video or the number of consumed samples,
12697 not including the current frame for audio, starting from 0.
12699 @item NB_CONSUMED_SAMPLES
12700 The number of consumed samples, not including the current frame (only
12703 @item NB_SAMPLES, S
12704 The number of samples in the current frame (only audio)
12706 @item SAMPLE_RATE, SR
12707 The audio sample rate.
12710 The PTS of the first frame.
12713 the time in seconds of the first frame
12716 State whether the current frame is interlaced.
12719 the time in seconds of the current frame
12722 original position in the file of the frame, or undefined if undefined
12723 for the current frame
12726 The previous input PTS.
12729 previous input time in seconds
12732 The previous output PTS.
12735 previous output time in seconds
12738 The wallclock (RTC) time in microseconds. This is deprecated, use time(0)
12742 The wallclock (RTC) time at the start of the movie in microseconds.
12745 The timebase of the input timestamps.
12749 @subsection Examples
12753 Start counting PTS from zero
12755 setpts=PTS-STARTPTS
12759 Apply fast motion effect:
12765 Apply slow motion effect:
12771 Set fixed rate of 25 frames per second:
12777 Set fixed rate 25 fps with some jitter:
12779 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
12783 Apply an offset of 10 seconds to the input PTS:
12789 Generate timestamps from a "live source" and rebase onto the current timebase:
12791 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
12795 Generate timestamps by counting samples:
12802 @section settb, asettb
12804 Set the timebase to use for the output frames timestamps.
12805 It is mainly useful for testing timebase configuration.
12807 It accepts the following parameters:
12812 The expression which is evaluated into the output timebase.
12816 The value for @option{tb} is an arithmetic expression representing a
12817 rational. The expression can contain the constants "AVTB" (the default
12818 timebase), "intb" (the input timebase) and "sr" (the sample rate,
12819 audio only). Default value is "intb".
12821 @subsection Examples
12825 Set the timebase to 1/25:
12831 Set the timebase to 1/10:
12837 Set the timebase to 1001/1000:
12843 Set the timebase to 2*intb:
12849 Set the default timebase value:
12856 Convert input audio to a video output representing
12857 frequency spectrum logarithmically (using constant Q transform with
12858 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
12860 The filter accepts the following options:
12864 Specify transform volume (multiplier) expression. The expression can contain
12867 @item frequency, freq, f
12868 the frequency where transform is evaluated
12869 @item timeclamp, tc
12870 value of timeclamp option
12874 @item a_weighting(f)
12875 A-weighting of equal loudness
12876 @item b_weighting(f)
12877 B-weighting of equal loudness
12878 @item c_weighting(f)
12879 C-weighting of equal loudness
12881 Default value is @code{16}.
12884 Specify transform length expression. The expression can contain variables:
12886 @item frequency, freq, f
12887 the frequency where transform is evaluated
12888 @item timeclamp, tc
12889 value of timeclamp option
12891 Default value is @code{384/f*tc/(384/f+tc)}.
12894 Specify the transform timeclamp. At low frequency, there is trade-off between
12895 accuracy in time domain and frequency domain. If timeclamp is lower,
12896 event in time domain is represented more accurately (such as fast bass drum),
12897 otherwise event in frequency domain is represented more accurately
12898 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
12901 Specify the transform coeffclamp. If coeffclamp is lower, transform is
12902 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
12903 Default value is @code{1.0}.
12906 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
12907 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
12908 Default value is @code{3.0}.
12911 Specify gamma of bargraph. Acceptable value is [1.0, 7.0].
12912 Default value is @code{1.0}.
12915 Specify font file for use with freetype. If not specified, use embedded font.
12918 Specify font color expression. This is arithmetic expression that should return
12919 integer value 0xRRGGBB. The expression can contain variables:
12921 @item frequency, freq, f
12922 the frequency where transform is evaluated
12923 @item timeclamp, tc
12924 value of timeclamp option
12929 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
12930 @item r(x), g(x), b(x)
12931 red, green, and blue value of intensity x
12933 Default value is @code{st(0, (midi(f)-59.5)/12);
12934 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
12935 r(1-ld(1)) + b(ld(1))}
12938 If set to 1 (the default), the video size is 1920x1080 (full HD),
12939 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
12942 Specify video fps. Default value is @code{25}.
12945 Specify number of transform per frame, so there are fps*count transforms
12946 per second. Note that audio data rate must be divisible by fps*count.
12947 Default value is @code{6}.
12951 @subsection Examples
12955 Playing audio while showing the spectrum:
12957 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
12961 Same as above, but with frame rate 30 fps:
12963 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
12967 Playing at 960x540 and lower CPU usage:
12969 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
12973 A1 and its harmonics: A1, A2, (near)E3, A3:
12975 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),
12976 asplit[a][out1]; [a] showcqt [out0]'
12980 Same as above, but with more accuracy in frequency domain (and slower):
12982 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),
12983 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
12987 B-weighting of equal loudness
12989 volume=16*b_weighting(f)
12995 tlength=100/f*tc/(100/f+tc)
12999 Custom fontcolor, C-note is colored green, others are colored blue
13001 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))'
13005 Custom gamma, now spectrum is linear to the amplitude.
13014 Convert input audio to video output representing the audio power spectrum.
13015 Audio amplitude is on Y-axis while frequency is on X-axis.
13017 The filter accepts the following options:
13021 Specify size of video. For the syntax of this option, check the
13022 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13023 Default is @code{1024x512}.
13027 This set how each frequency bin will be represented.
13029 It accepts the following values:
13035 Default is @code{bar}.
13038 Set amplitude scale.
13040 It accepts the following values:
13054 Default is @code{log}.
13057 Set frequency scale.
13059 It accepts the following values:
13068 Reverse logarithmic scale.
13070 Default is @code{lin}.
13075 It accepts the following values:
13091 Default is @code{w2048}
13094 Set windowing function.
13096 It accepts the following values:
13111 Default is @code{hanning}.
13114 Set window overlap. In range @code{[0, 1]}. Default is @code{1},
13115 which means optimal overlap for selected window function will be picked.
13118 Set time averaging. Setting this to 0 will display current maximal peaks.
13119 Default is @code{1}, which means time averaging is disabled.
13122 Specify list of colors separated by space or by '|' which will be used to
13123 draw channel frequencies. Unrecognized or missing colors will be replaced
13127 @section showspectrum
13129 Convert input audio to a video output, representing the audio frequency
13132 The filter accepts the following options:
13136 Specify the video size for the output. For the syntax of this option, check the
13137 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13138 Default value is @code{640x512}.
13141 Specify how the spectrum should slide along the window.
13143 It accepts the following values:
13146 the samples start again on the left when they reach the right
13148 the samples scroll from right to left
13150 frames are only produced when the samples reach the right
13153 Default value is @code{replace}.
13156 Specify display mode.
13158 It accepts the following values:
13161 all channels are displayed in the same row
13163 all channels are displayed in separate rows
13166 Default value is @samp{combined}.
13169 Specify display color mode.
13171 It accepts the following values:
13174 each channel is displayed in a separate color
13176 each channel is is displayed using the same color scheme
13179 Default value is @samp{channel}.
13182 Specify scale used for calculating intensity color values.
13184 It accepts the following values:
13189 square root, default
13196 Default value is @samp{sqrt}.
13199 Set saturation modifier for displayed colors. Negative values provide
13200 alternative color scheme. @code{0} is no saturation at all.
13201 Saturation must be in [-10.0, 10.0] range.
13202 Default value is @code{1}.
13205 Set window function.
13207 It accepts the following values:
13210 No samples pre-processing (do not expect this to be faster)
13219 Default value is @code{hann}.
13222 The usage is very similar to the showwaves filter; see the examples in that
13225 @subsection Examples
13229 Large window with logarithmic color scaling:
13231 showspectrum=s=1280x480:scale=log
13235 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
13237 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
13238 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
13242 @section showvolume
13244 Convert input audio volume to a video output.
13246 The filter accepts the following options:
13253 Set border width, allowed range is [0, 5]. Default is 1.
13256 Set channel width, allowed range is [40, 1080]. Default is 400.
13259 Set channel height, allowed range is [1, 100]. Default is 20.
13262 Set fade, allowed range is [1, 255]. Default is 20.
13265 Set volume color expression.
13267 The expression can use the following variables:
13271 Current max volume of channel in dB.
13274 Current channel number, starting from 0.
13278 If set, displays channel names. Default is enabled.
13283 Convert input audio to a video output, representing the samples waves.
13285 The filter accepts the following options:
13289 Specify the video size for the output. For the syntax of this option, check the
13290 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13291 Default value is @code{600x240}.
13296 Available values are:
13299 Draw a point for each sample.
13302 Draw a vertical line for each sample.
13305 Draw a point for each sample and a line between them.
13308 Draw a centered vertical line for each sample.
13311 Default value is @code{point}.
13314 Set the number of samples which are printed on the same column. A
13315 larger value will decrease the frame rate. Must be a positive
13316 integer. This option can be set only if the value for @var{rate}
13317 is not explicitly specified.
13320 Set the (approximate) output frame rate. This is done by setting the
13321 option @var{n}. Default value is "25".
13323 @item split_channels
13324 Set if channels should be drawn separately or overlap. Default value is 0.
13328 @subsection Examples
13332 Output the input file audio and the corresponding video representation
13335 amovie=a.mp3,asplit[out0],showwaves[out1]
13339 Create a synthetic signal and show it with showwaves, forcing a
13340 frame rate of 30 frames per second:
13342 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
13346 @section showwavespic
13348 Convert input audio to a single video frame, representing the samples waves.
13350 The filter accepts the following options:
13354 Specify the video size for the output. For the syntax of this option, check the
13355 @ref{video size syntax,,"Video size" section in the ffmpeg-utils manual,ffmpeg-utils}.
13356 Default value is @code{600x240}.
13358 @item split_channels
13359 Set if channels should be drawn separately or overlap. Default value is 0.
13362 @subsection Examples
13366 Extract a channel split representation of the wave form of a whole audio track
13367 in a 1024x800 picture using @command{ffmpeg}:
13369 ffmpeg -i audio.flac -lavfi showwavespic=split_channels=1:s=1024x800 waveform.png
13373 @section split, asplit
13375 Split input into several identical outputs.
13377 @code{asplit} works with audio input, @code{split} with video.
13379 The filter accepts a single parameter which specifies the number of outputs. If
13380 unspecified, it defaults to 2.
13382 @subsection Examples
13386 Create two separate outputs from the same input:
13388 [in] split [out0][out1]
13392 To create 3 or more outputs, you need to specify the number of
13395 [in] asplit=3 [out0][out1][out2]
13399 Create two separate outputs from the same input, one cropped and
13402 [in] split [splitout1][splitout2];
13403 [splitout1] crop=100:100:0:0 [cropout];
13404 [splitout2] pad=200:200:100:100 [padout];
13408 Create 5 copies of the input audio with @command{ffmpeg}:
13410 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
13416 Receive commands sent through a libzmq client, and forward them to
13417 filters in the filtergraph.
13419 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
13420 must be inserted between two video filters, @code{azmq} between two
13423 To enable these filters you need to install the libzmq library and
13424 headers and configure FFmpeg with @code{--enable-libzmq}.
13426 For more information about libzmq see:
13427 @url{http://www.zeromq.org/}
13429 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
13430 receives messages sent through a network interface defined by the
13431 @option{bind_address} option.
13433 The received message must be in the form:
13435 @var{TARGET} @var{COMMAND} [@var{ARG}]
13438 @var{TARGET} specifies the target of the command, usually the name of
13439 the filter class or a specific filter instance name.
13441 @var{COMMAND} specifies the name of the command for the target filter.
13443 @var{ARG} is optional and specifies the optional argument list for the
13444 given @var{COMMAND}.
13446 Upon reception, the message is processed and the corresponding command
13447 is injected into the filtergraph. Depending on the result, the filter
13448 will send a reply to the client, adopting the format:
13450 @var{ERROR_CODE} @var{ERROR_REASON}
13454 @var{MESSAGE} is optional.
13456 @subsection Examples
13458 Look at @file{tools/zmqsend} for an example of a zmq client which can
13459 be used to send commands processed by these filters.
13461 Consider the following filtergraph generated by @command{ffplay}
13463 ffplay -dumpgraph 1 -f lavfi "
13464 color=s=100x100:c=red [l];
13465 color=s=100x100:c=blue [r];
13466 nullsrc=s=200x100, zmq [bg];
13467 [bg][l] overlay [bg+l];
13468 [bg+l][r] overlay=x=100 "
13471 To change the color of the left side of the video, the following
13472 command can be used:
13474 echo Parsed_color_0 c yellow | tools/zmqsend
13477 To change the right side:
13479 echo Parsed_color_1 c pink | tools/zmqsend
13482 @c man end MULTIMEDIA FILTERS
13484 @chapter Multimedia Sources
13485 @c man begin MULTIMEDIA SOURCES
13487 Below is a description of the currently available multimedia sources.
13491 This is the same as @ref{movie} source, except it selects an audio
13497 Read audio and/or video stream(s) from a movie container.
13499 It accepts the following parameters:
13503 The name of the resource to read (not necessarily a file; it can also be a
13504 device or a stream accessed through some protocol).
13506 @item format_name, f
13507 Specifies the format assumed for the movie to read, and can be either
13508 the name of a container or an input device. If not specified, the
13509 format is guessed from @var{movie_name} or by probing.
13511 @item seek_point, sp
13512 Specifies the seek point in seconds. The frames will be output
13513 starting from this seek point. The parameter is evaluated with
13514 @code{av_strtod}, so the numerical value may be suffixed by an IS
13515 postfix. The default value is "0".
13518 Specifies the streams to read. Several streams can be specified,
13519 separated by "+". The source will then have as many outputs, in the
13520 same order. The syntax is explained in the ``Stream specifiers''
13521 section in the ffmpeg manual. Two special names, "dv" and "da" specify
13522 respectively the default (best suited) video and audio stream. Default
13523 is "dv", or "da" if the filter is called as "amovie".
13525 @item stream_index, si
13526 Specifies the index of the video stream to read. If the value is -1,
13527 the most suitable video stream will be automatically selected. The default
13528 value is "-1". Deprecated. If the filter is called "amovie", it will select
13529 audio instead of video.
13532 Specifies how many times to read the stream in sequence.
13533 If the value is less than 1, the stream will be read again and again.
13534 Default value is "1".
13536 Note that when the movie is looped the source timestamps are not
13537 changed, so it will generate non monotonically increasing timestamps.
13540 It allows overlaying a second video on top of the main input of
13541 a filtergraph, as shown in this graph:
13543 input -----------> deltapts0 --> overlay --> output
13546 movie --> scale--> deltapts1 -------+
13548 @subsection Examples
13552 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
13553 on top of the input labelled "in":
13555 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
13556 [in] setpts=PTS-STARTPTS [main];
13557 [main][over] overlay=16:16 [out]
13561 Read from a video4linux2 device, and overlay it on top of the input
13564 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
13565 [in] setpts=PTS-STARTPTS [main];
13566 [main][over] overlay=16:16 [out]
13570 Read the first video stream and the audio stream with id 0x81 from
13571 dvd.vob; the video is connected to the pad named "video" and the audio is
13572 connected to the pad named "audio":
13574 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
13578 @c man end MULTIMEDIA SOURCES