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
118 recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
119 options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the
120 @code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} functions defined in
121 @file{libavfilter/avfilter.h}.
123 A filterchain consists of a sequence of connected filters, each one
124 connected to the previous one in the sequence. A filterchain is
125 represented by a list of ","-separated filter descriptions.
127 A filtergraph consists of a sequence of filterchains. A sequence of
128 filterchains is represented by a list of ";"-separated filterchain
131 A filter is represented by a string of the form:
132 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
134 @var{filter_name} is the name of the filter class of which the
135 described filter is an instance of, and has to be the name of one of
136 the filter classes registered in the program.
137 The name of the filter class is optionally followed by a string
140 @var{arguments} is a string which contains the parameters used to
141 initialize the filter instance. It may have one of two forms:
145 A ':'-separated list of @var{key=value} pairs.
148 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
149 the option names in the order they are declared. E.g. the @code{fade} filter
150 declares three options in this order -- @option{type}, @option{start_frame} and
151 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
152 @var{in} is assigned to the option @option{type}, @var{0} to
153 @option{start_frame} and @var{30} to @option{nb_frames}.
156 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
157 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
158 follow the same constraints order of the previous point. The following
159 @var{key=value} pairs can be set in any preferred order.
163 If the option value itself is a list of items (e.g. the @code{format} filter
164 takes a list of pixel formats), the items in the list are usually separated by
167 The list of arguments can be quoted using the character "'" as initial
168 and ending mark, and the character '\' for escaping the characters
169 within the quoted text; otherwise the argument string is considered
170 terminated when the next special character (belonging to the set
171 "[]=;,") is encountered.
173 The name and arguments of the filter are optionally preceded and
174 followed by a list of link labels.
175 A link label allows one to name a link and associate it to a filter output
176 or input pad. The preceding labels @var{in_link_1}
177 ... @var{in_link_N}, are associated to the filter input pads,
178 the following labels @var{out_link_1} ... @var{out_link_M}, are
179 associated to the output pads.
181 When two link labels with the same name are found in the
182 filtergraph, a link between the corresponding input and output pad is
185 If an output pad is not labelled, it is linked by default to the first
186 unlabelled input pad of the next filter in the filterchain.
187 For example in the filterchain
189 nullsrc, split[L1], [L2]overlay, nullsink
191 the split filter instance has two output pads, and the overlay filter
192 instance two input pads. The first output pad of split is labelled
193 "L1", the first input pad of overlay is labelled "L2", and the second
194 output pad of split is linked to the second input pad of overlay,
195 which are both unlabelled.
197 In a complete filterchain all the unlabelled filter input and output
198 pads must be connected. A filtergraph is considered valid if all the
199 filter input and output pads of all the filterchains are connected.
201 Libavfilter will automatically insert @ref{scale} filters where format
202 conversion is required. It is possible to specify swscale flags
203 for those automatically inserted scalers by prepending
204 @code{sws_flags=@var{flags};}
205 to the filtergraph description.
207 Here is a BNF description of the filtergraph syntax:
209 @var{NAME} ::= sequence of alphanumeric characters and '_'
210 @var{LINKLABEL} ::= "[" @var{NAME} "]"
211 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
212 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
213 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
214 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
215 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
218 @section Notes on filtergraph escaping
220 Filtergraph description composition entails several levels of
221 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
222 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
223 information about the employed escaping procedure.
225 A first level escaping affects the content of each filter option
226 value, which may contain the special character @code{:} used to
227 separate values, or one of the escaping characters @code{\'}.
229 A second level escaping affects the whole filter description, which
230 may contain the escaping characters @code{\'} or the special
231 characters @code{[],;} used by the filtergraph description.
233 Finally, when you specify a filtergraph on a shell commandline, you
234 need to perform a third level escaping for the shell special
235 characters contained within it.
237 For example, consider the following string to be embedded in
238 the @ref{drawtext} filter description @option{text} value:
240 this is a 'string': may contain one, or more, special characters
243 This string contains the @code{'} special escaping character, and the
244 @code{:} special character, so it needs to be escaped in this way:
246 text=this is a \'string\'\: may contain one, or more, special characters
249 A second level of escaping is required when embedding the filter
250 description in a filtergraph description, in order to escape all the
251 filtergraph special characters. Thus the example above becomes:
253 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
255 (note that in addition to the @code{\'} escaping special characters,
256 also @code{,} needs to be escaped).
258 Finally an additional level of escaping is needed when writing the
259 filtergraph description in a shell command, which depends on the
260 escaping rules of the adopted shell. For example, assuming that
261 @code{\} is special and needs to be escaped with another @code{\}, the
262 previous string will finally result in:
264 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
267 @chapter Timeline editing
269 Some filters support a generic @option{enable} option. For the filters
270 supporting timeline editing, this option can be set to an expression which is
271 evaluated before sending a frame to the filter. If the evaluation is non-zero,
272 the filter will be enabled, otherwise the frame will be sent unchanged to the
273 next filter in the filtergraph.
275 The expression accepts the following values:
278 timestamp expressed in seconds, NAN if the input timestamp is unknown
281 sequential number of the input frame, starting from 0
284 the position in the file of the input frame, NAN if unknown
287 Additionally, these filters support an @option{enable} command that can be used
288 to re-define the expression.
290 Like any other filtering option, the @option{enable} option follows the same
293 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
294 minutes, and a @ref{curves} filter starting at 3 seconds:
296 smartblur = enable='between(t,10,3*60)',
297 curves = enable='gte(t,3)' : preset=cross_process
300 @c man end FILTERGRAPH DESCRIPTION
302 @chapter Audio Filters
303 @c man begin AUDIO FILTERS
305 When you configure your FFmpeg build, you can disable any of the
306 existing filters using @code{--disable-filters}.
307 The configure output will show the audio filters included in your
310 Below is a description of the currently available audio filters.
314 Convert the input audio format to the specified formats.
316 @emph{This filter is deprecated. Use @ref{aformat} instead.}
318 The filter accepts a string of the form:
319 "@var{sample_format}:@var{channel_layout}".
321 @var{sample_format} specifies the sample format, and can be a string or the
322 corresponding numeric value defined in @file{libavutil/samplefmt.h}. Use 'p'
323 suffix for a planar sample format.
325 @var{channel_layout} specifies the channel layout, and can be a string
326 or the corresponding number value defined in @file{libavutil/channel_layout.h}.
328 The special parameter "auto", signifies that the filter will
329 automatically select the output format depending on the output filter.
335 Convert input to float, planar, stereo:
341 Convert input to unsigned 8-bit, automatically select out channel layout:
349 Delay one or more audio channels.
351 Samples in delayed channel are filled with silence.
353 The filter accepts the following option:
357 Set list of delays in milliseconds for each channel separated by '|'.
358 At least one delay greater than 0 should be provided.
359 Unused delays will be silently ignored. If number of given delays is
360 smaller than number of channels all remaining channels will not be delayed.
367 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
368 the second channel (and any other channels that may be present) unchanged.
376 Apply echoing to the input audio.
378 Echoes are reflected sound and can occur naturally amongst mountains
379 (and sometimes large buildings) when talking or shouting; digital echo
380 effects emulate this behaviour and are often used to help fill out the
381 sound of a single instrument or vocal. The time difference between the
382 original signal and the reflection is the @code{delay}, and the
383 loudness of the reflected signal is the @code{decay}.
384 Multiple echoes can have different delays and decays.
386 A description of the accepted parameters follows.
390 Set input gain of reflected signal. Default is @code{0.6}.
393 Set output gain of reflected signal. Default is @code{0.3}.
396 Set list of time intervals in milliseconds between original signal and reflections
397 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
398 Default is @code{1000}.
401 Set list of loudnesses of reflected signals separated by '|'.
402 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
403 Default is @code{0.5}.
410 Make it sound as if there are twice as many instruments as are actually playing:
412 aecho=0.8:0.88:60:0.4
416 If delay is very short, then it sound like a (metallic) robot playing music:
422 A longer delay will sound like an open air concert in the mountains:
424 aecho=0.8:0.9:1000:0.3
428 Same as above but with one more mountain:
430 aecho=0.8:0.9:1000|1800:0.3|0.25
436 Modify an audio signal according to the specified expressions.
438 This filter accepts one or more expressions (one for each channel),
439 which are evaluated and used to modify a corresponding audio signal.
441 It accepts the following parameters:
445 Set the '|'-separated expressions list for each separate channel. If
446 the number of input channels is greater than the number of
447 expressions, the last specified expression is used for the remaining
450 @item channel_layout, c
451 Set output channel layout. If not specified, the channel layout is
452 specified by the number of expressions. If set to @samp{same}, it will
453 use by default the same input channel layout.
456 Each expression in @var{exprs} can contain the following constants and functions:
460 channel number of the current expression
463 number of the evaluated sample, starting from 0
469 time of the evaluated sample expressed in seconds
472 @item nb_out_channels
473 input and output number of channels
476 the value of input channel with number @var{CH}
479 Note: this filter is slow. For faster processing you should use a
488 aeval=val(ch)/2:c=same
492 Invert phase of the second channel:
500 Apply fade-in/out effect to input audio.
502 A description of the accepted parameters follows.
506 Specify the effect type, can be either @code{in} for fade-in, or
507 @code{out} for a fade-out effect. Default is @code{in}.
509 @item start_sample, ss
510 Specify the number of the start sample for starting to apply the fade
511 effect. Default is 0.
514 Specify the number of samples for which the fade effect has to last. At
515 the end of the fade-in effect the output audio will have the same
516 volume as the input audio, at the end of the fade-out transition
517 the output audio will be silence. Default is 44100.
520 Specify time for starting to apply the fade effect. Default is 0.
521 The accepted syntax is:
523 [-]HH[:MM[:SS[.m...]]]
526 See also the function @code{av_parse_time()}.
527 If set this option is used instead of @var{start_sample} one.
530 Specify the duration for which the fade effect has to last. Default is 0.
531 The accepted syntax is:
533 [-]HH[:MM[:SS[.m...]]]
536 See also the function @code{av_parse_time()}.
537 At the end of the fade-in effect the output audio will have the same
538 volume as the input audio, at the end of the fade-out transition
539 the output audio will be silence.
540 If set this option is used instead of @var{nb_samples} one.
543 Set curve for fade transition.
545 It accepts the following values:
548 select triangular, linear slope (default)
550 select quarter of sine wave
552 select half of sine wave
554 select exponential sine wave
558 select inverted parabola
574 Fade in first 15 seconds of audio:
580 Fade out last 25 seconds of a 900 seconds audio:
582 afade=t=out:st=875:d=25
589 Set output format constraints for the input audio. The framework will
590 negotiate the most appropriate format to minimize conversions.
592 It accepts the following parameters:
596 A '|'-separated list of requested sample formats.
599 A '|'-separated list of requested sample rates.
601 @item channel_layouts
602 A '|'-separated list of requested channel layouts.
604 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
605 for the required syntax.
608 If a parameter is omitted, all values are allowed.
610 Force the output to either unsigned 8-bit or signed 16-bit stereo
612 aformat=sample_fmts=u8|s16:channel_layouts=stereo
617 Apply a two-pole all-pass filter with central frequency (in Hz)
618 @var{frequency}, and filter-width @var{width}.
619 An all-pass filter changes the audio's frequency to phase relationship
620 without changing its frequency to amplitude relationship.
622 The filter accepts the following options:
629 Set method to specify band-width of filter.
642 Specify the band-width of a filter in width_type units.
647 Merge two or more audio streams into a single multi-channel stream.
649 The filter accepts the following options:
654 Set the number of inputs. Default is 2.
658 If the channel layouts of the inputs are disjoint, and therefore compatible,
659 the channel layout of the output will be set accordingly and the channels
660 will be reordered as necessary. If the channel layouts of the inputs are not
661 disjoint, the output will have all the channels of the first input then all
662 the channels of the second input, in that order, and the channel layout of
663 the output will be the default value corresponding to the total number of
666 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
667 is FC+BL+BR, then the output will be in 5.1, with the channels in the
668 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
669 first input, b1 is the first channel of the second input).
671 On the other hand, if both input are in stereo, the output channels will be
672 in the default order: a1, a2, b1, b2, and the channel layout will be
673 arbitrarily set to 4.0, which may or may not be the expected value.
675 All inputs must have the same sample rate, and format.
677 If inputs do not have the same duration, the output will stop with the
684 Merge two mono files into a stereo stream:
686 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
690 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
692 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
698 Mixes multiple audio inputs into a single output.
700 Note that this filter only supports float samples (the @var{amerge}
701 and @var{pan} audio filters support many formats). If the @var{amix}
702 input has integer samples then @ref{aresample} will be automatically
703 inserted to perform the conversion to float samples.
707 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
709 will mix 3 input audio streams to a single output with the same duration as the
710 first input and a dropout transition time of 3 seconds.
712 It accepts the following parameters:
716 The number of inputs. If unspecified, it defaults to 2.
719 How to determine the end-of-stream.
723 The duration of the longest input. (default)
726 The duration of the shortest input.
729 The duration of the first input.
733 @item dropout_transition
734 The transition time, in seconds, for volume renormalization when an input
735 stream ends. The default value is 2 seconds.
741 Pass the audio source unchanged to the output.
745 Pad the end of a audio stream with silence, this can be used together with
746 -shortest to extend audio streams to the same length as the video stream.
749 Add a phasing effect to the input audio.
751 A phaser filter creates series of peaks and troughs in the frequency spectrum.
752 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
754 A description of the accepted parameters follows.
758 Set input gain. Default is 0.4.
761 Set output gain. Default is 0.74
764 Set delay in milliseconds. Default is 3.0.
767 Set decay. Default is 0.4.
770 Set modulation speed in Hz. Default is 0.5.
773 Set modulation type. Default is triangular.
775 It accepts the following values:
785 Resample the input audio to the specified parameters, using the
786 libswresample library. If none are specified then the filter will
787 automatically convert between its input and output.
789 This filter is also able to stretch/squeeze the audio data to make it match
790 the timestamps or to inject silence / cut out audio to make it match the
791 timestamps, do a combination of both or do neither.
793 The filter accepts the syntax
794 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
795 expresses a sample rate and @var{resampler_options} is a list of
796 @var{key}=@var{value} pairs, separated by ":". See the
797 ffmpeg-resampler manual for the complete list of supported options.
803 Resample the input audio to 44100Hz:
809 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
810 samples per second compensation:
816 @section asetnsamples
818 Set the number of samples per each output audio frame.
820 The last output packet may contain a different number of samples, as
821 the filter will flush all the remaining samples when the input audio
824 The filter accepts the following options:
828 @item nb_out_samples, n
829 Set the number of frames per each output audio frame. The number is
830 intended as the number of samples @emph{per each channel}.
831 Default value is 1024.
834 If set to 1, the filter will pad the last audio frame with zeroes, so
835 that the last frame will contain the same number of samples as the
836 previous ones. Default value is 1.
839 For example, to set the number of per-frame samples to 1234 and
840 disable padding for the last frame, use:
842 asetnsamples=n=1234:p=0
847 Set the sample rate without altering the PCM data.
848 This will result in a change of speed and pitch.
850 The filter accepts the following options:
854 Set the output sample rate. Default is 44100 Hz.
859 Show a line containing various information for each input audio frame.
860 The input audio is not modified.
862 The shown line contains a sequence of key/value pairs of the form
863 @var{key}:@var{value}.
865 It accepts the following parameters:
869 The (sequential) number of the input frame, starting from 0.
872 The presentation timestamp of the input frame, in time base units; the time base
873 depends on the filter input pad, and is usually 1/@var{sample_rate}.
876 The presentation timestamp of the input frame in seconds.
879 position of the frame in the input stream, -1 if this information in
880 unavailable and/or meaningless (for example in case of synthetic audio)
889 The sample rate for the audio frame.
892 The number of samples (per channel) in the frame.
895 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
896 audio, the data is treated as if all the planes were concatenated.
898 @item plane_checksums
899 A list of Adler-32 checksums for each data plane.
904 Display time domain statistical information about the audio channels.
905 Statistics are calculated and displayed for each audio channel and,
906 where applicable, an overall figure is also given.
908 It accepts the following option:
911 Short window length in seconds, used for peak and trough RMS measurement.
912 Default is @code{0.05} (50 miliseconds). Allowed range is @code{[0.1 - 10]}.
915 A description of each shown parameter follows:
919 Mean amplitude displacement from zero.
922 Minimal sample level.
925 Maximal sample level.
929 Standard peak and RMS level measured in dBFS.
933 Peak and trough values for RMS level measured over a short window.
936 Standard ratio of peak to RMS level (note: not in dB).
939 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
940 (i.e. either @var{Min level} or @var{Max level}).
943 Number of occasions (not the number of samples) that the signal attained either
944 @var{Min level} or @var{Max level}.
949 Forward two audio streams and control the order the buffers are forwarded.
951 The filter accepts the following options:
955 Set the expression deciding which stream should be
956 forwarded next: if the result is negative, the first stream is forwarded; if
957 the result is positive or zero, the second stream is forwarded. It can use
958 the following variables:
962 number of buffers forwarded so far on each stream
964 number of samples forwarded so far on each stream
966 current timestamp of each stream
969 The default value is @code{t1-t2}, which means to always forward the stream
970 that has a smaller timestamp.
975 Stress-test @code{amerge} by randomly sending buffers on the wrong
976 input, while avoiding too much of a desynchronization:
978 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
979 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
985 Synchronize audio data with timestamps by squeezing/stretching it and/or
986 dropping samples/adding silence when needed.
988 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
990 It accepts the following parameters:
994 Enable stretching/squeezing the data to make it match the timestamps. Disabled
995 by default. When disabled, time gaps are covered with silence.
998 The minimum difference between timestamps and audio data (in seconds) to trigger
999 adding/dropping samples. The default value is 0.1. If you get an imperfect
1000 sync with this filter, try setting this parameter to 0.
1003 The maximum compensation in samples per second. Only relevant with compensate=1.
1004 The default value is 500.
1007 Assume that the first PTS should be this value. The time base is 1 / sample
1008 rate. This allows for padding/trimming at the start of the stream. By default,
1009 no assumption is made about the first frame's expected PTS, so no padding or
1010 trimming is done. For example, this could be set to 0 to pad the beginning with
1011 silence if an audio stream starts after the video stream or to trim any samples
1012 with a negative PTS due to encoder delay.
1020 The filter accepts exactly one parameter, the audio tempo. If not
1021 specified then the filter will assume nominal 1.0 tempo. Tempo must
1022 be in the [0.5, 2.0] range.
1024 @subsection Examples
1028 Slow down audio to 80% tempo:
1034 To speed up audio to 125% tempo:
1042 Trim the input so that the output contains one continuous subpart of the input.
1044 It accepts the following parameters:
1047 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1048 sample with the timestamp @var{start} will be the first sample in the output.
1051 Specify time of the first audio sample that will be dropped, i.e. the
1052 audio sample immediately preceding the one with the timestamp @var{end} will be
1053 the last sample in the output.
1056 Same as @var{start}, except this option sets the start timestamp in samples
1060 Same as @var{end}, except this option sets the end timestamp in samples instead
1064 The maximum duration of the output in seconds.
1067 The number of the first sample that should be output.
1070 The number of the first sample that should be dropped.
1073 @option{start}, @option{end}, @option{duration} are expressed as time
1074 duration specifications, check the "Time duration" section in the
1075 ffmpeg-utils manual.
1077 Note that the first two sets of the start/end options and the @option{duration}
1078 option look at the frame timestamp, while the _sample options simply count the
1079 samples that pass through the filter. So start/end_pts and start/end_sample will
1080 give different results when the timestamps are wrong, inexact or do not start at
1081 zero. Also note that this filter does not modify the timestamps. If you wish
1082 to have the output timestamps start at zero, insert the asetpts filter after the
1085 If multiple start or end options are set, this filter tries to be greedy and
1086 keep all samples that match at least one of the specified constraints. To keep
1087 only the part that matches all the constraints at once, chain multiple atrim
1090 The defaults are such that all the input is kept. So it is possible to set e.g.
1091 just the end values to keep everything before the specified time.
1096 Drop everything except the second minute of input:
1098 ffmpeg -i INPUT -af atrim=60:120
1102 Keep only the first 1000 samples:
1104 ffmpeg -i INPUT -af atrim=end_sample=1000
1111 Apply a two-pole Butterworth band-pass filter with central
1112 frequency @var{frequency}, and (3dB-point) band-width width.
1113 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1114 instead of the default: constant 0dB peak gain.
1115 The filter roll off at 6dB per octave (20dB per decade).
1117 The filter accepts the following options:
1121 Set the filter's central frequency. Default is @code{3000}.
1124 Constant skirt gain if set to 1. Defaults to 0.
1127 Set method to specify band-width of filter.
1140 Specify the band-width of a filter in width_type units.
1145 Apply a two-pole Butterworth band-reject filter with central
1146 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1147 The filter roll off at 6dB per octave (20dB per decade).
1149 The filter accepts the following options:
1153 Set the filter's central frequency. Default is @code{3000}.
1156 Set method to specify band-width of filter.
1169 Specify the band-width of a filter in width_type units.
1174 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1175 shelving filter with a response similar to that of a standard
1176 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1178 The filter accepts the following options:
1182 Give the gain at 0 Hz. Its useful range is about -20
1183 (for a large cut) to +20 (for a large boost).
1184 Beware of clipping when using a positive gain.
1187 Set the filter's central frequency and so can be used
1188 to extend or reduce the frequency range to be boosted or cut.
1189 The default value is @code{100} Hz.
1192 Set method to specify band-width of filter.
1205 Determine how steep is the filter's shelf transition.
1210 Apply a biquad IIR filter with the given coefficients.
1211 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1212 are the numerator and denominator coefficients respectively.
1215 Bauer stereo to binaural transformation, which improves headphone listening of
1216 stereo audio records.
1218 It accepts the following parameters:
1222 Pre-defined crossfeed level.
1226 Default level (fcut=700, feed=50).
1229 Chu Moy circuit (fcut=700, feed=60).
1232 Jan Meier circuit (fcut=650, feed=95).
1237 Cut frequency (in Hz).
1246 Remap input channels to new locations.
1248 It accepts the following parameters:
1250 @item channel_layout
1251 The channel layout of the output stream.
1254 Map channels from input to output. The argument is a '|'-separated list of
1255 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1256 @var{in_channel} form. @var{in_channel} can be either the name of the input
1257 channel (e.g. FL for front left) or its index in the input channel layout.
1258 @var{out_channel} is the name of the output channel or its index in the output
1259 channel layout. If @var{out_channel} is not given then it is implicitly an
1260 index, starting with zero and increasing by one for each mapping.
1263 If no mapping is present, the filter will implicitly map input channels to
1264 output channels, preserving indices.
1266 For example, assuming a 5.1+downmix input MOV file,
1268 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1270 will create an output WAV file tagged as stereo from the downmix channels of
1273 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1275 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1278 @section channelsplit
1280 Split each channel from an input audio stream into a separate output stream.
1282 It accepts the following parameters:
1284 @item channel_layout
1285 The channel layout of the input stream. The default is "stereo".
1288 For example, assuming a stereo input MP3 file,
1290 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1292 will create an output Matroska file with two audio streams, one containing only
1293 the left channel and the other the right channel.
1295 Split a 5.1 WAV file into per-channel files:
1297 ffmpeg -i in.wav -filter_complex
1298 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1299 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1300 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1305 Compress or expand the audio's dynamic range.
1307 It accepts the following parameters:
1313 A list of times in seconds for each channel over which the instantaneous level
1314 of the input signal is averaged to determine its volume. @var{attacks} refers to
1315 increase of volume and @var{decays} refers to decrease of volume. For most
1316 situations, the attack time (response to the audio getting louder) should be
1317 shorter than the decay time, because the human ear is more sensitive to sudden
1318 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1319 a typical value for decay is 0.8 seconds.
1322 A list of points for the transfer function, specified in dB relative to the
1323 maximum possible signal amplitude. Each key points list must be defined using
1324 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1325 @code{x0/y0 x1/y1 x2/y2 ....}
1327 The input values must be in strictly increasing order but the transfer function
1328 does not have to be monotonically rising. The point @code{0/0} is assumed but
1329 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1330 function are @code{-70/-70|-60/-20}.
1333 Set the curve radius in dB for all joints. It defaults to 0.01.
1336 Set the additional gain in dB to be applied at all points on the transfer
1337 function. This allows for easy adjustment of the overall gain.
1341 Set an initial volume, in dB, to be assumed for each channel when filtering
1342 starts. This permits the user to supply a nominal level initially, so that, for
1343 example, a very large gain is not applied to initial signal levels before the
1344 companding has begun to operate. A typical value for audio which is initially
1345 quiet is -90 dB. It defaults to 0.
1348 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1349 delayed before being fed to the volume adjuster. Specifying a delay
1350 approximately equal to the attack/decay times allows the filter to effectively
1351 operate in predictive rather than reactive mode. It defaults to 0.
1355 @subsection Examples
1359 Make music with both quiet and loud passages suitable for listening to in a
1362 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1366 A noise gate for when the noise is at a lower level than the signal:
1368 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1372 Here is another noise gate, this time for when the noise is at a higher level
1373 than the signal (making it, in some ways, similar to squelch):
1375 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1381 Make audio easier to listen to on headphones.
1383 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1384 so that when listened to on headphones the stereo image is moved from
1385 inside your head (standard for headphones) to outside and in front of
1386 the listener (standard for speakers).
1392 Apply a two-pole peaking equalisation (EQ) filter. With this
1393 filter, the signal-level at and around a selected frequency can
1394 be increased or decreased, whilst (unlike bandpass and bandreject
1395 filters) that at all other frequencies is unchanged.
1397 In order to produce complex equalisation curves, this filter can
1398 be given several times, each with a different central frequency.
1400 The filter accepts the following options:
1404 Set the filter's central frequency in Hz.
1407 Set method to specify band-width of filter.
1420 Specify the band-width of a filter in width_type units.
1423 Set the required gain or attenuation in dB.
1424 Beware of clipping when using a positive gain.
1427 @subsection Examples
1430 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1432 equalizer=f=1000:width_type=h:width=200:g=-10
1436 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1438 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1443 Apply a flanging effect to the audio.
1445 The filter accepts the following options:
1449 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
1452 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
1455 Set percentage regeneneration (delayed signal feedback). Range from -95 to 95.
1459 Set percentage of delayed signal mixed with original. Range from 0 to 100.
1463 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
1466 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
1467 Default value is @var{sinusoidal}.
1470 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
1471 Default value is 25.
1474 Set delay-line interpolation, @var{linear} or @var{quadratic}.
1475 Default is @var{linear}.
1480 Apply a high-pass filter with 3dB point frequency.
1481 The filter can be either single-pole, or double-pole (the default).
1482 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1484 The filter accepts the following options:
1488 Set frequency in Hz. Default is 3000.
1491 Set number of poles. Default is 2.
1494 Set method to specify band-width of filter.
1507 Specify the band-width of a filter in width_type units.
1508 Applies only to double-pole filter.
1509 The default is 0.707q and gives a Butterworth response.
1514 Join multiple input streams into one multi-channel stream.
1516 It accepts the following parameters:
1520 The number of input streams. It defaults to 2.
1522 @item channel_layout
1523 The desired output channel layout. It defaults to stereo.
1526 Map channels from inputs to output. The argument is a '|'-separated list of
1527 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1528 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1529 can be either the name of the input channel (e.g. FL for front left) or its
1530 index in the specified input stream. @var{out_channel} is the name of the output
1534 The filter will attempt to guess the mappings when they are not specified
1535 explicitly. It does so by first trying to find an unused matching input channel
1536 and if that fails it picks the first unused input channel.
1538 Join 3 inputs (with properly set channel layouts):
1540 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1543 Build a 5.1 output from 6 single-channel streams:
1545 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1546 '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'
1552 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1554 To enable compilation of this filter you need to configure FFmpeg with
1555 @code{--enable-ladspa}.
1559 Specifies the name of LADSPA plugin library to load. If the environment
1560 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1561 each one of the directories specified by the colon separated list in
1562 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1563 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1564 @file{/usr/lib/ladspa/}.
1567 Specifies the plugin within the library. Some libraries contain only
1568 one plugin, but others contain many of them. If this is not set filter
1569 will list all available plugins within the specified library.
1572 Set the '|' separated list of controls which are zero or more floating point
1573 values that determine the behavior of the loaded plugin (for example delay,
1575 Controls need to be defined using the following syntax:
1576 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1577 @var{valuei} is the value set on the @var{i}-th control.
1578 If @option{controls} is set to @code{help}, all available controls and
1579 their valid ranges are printed.
1581 @item sample_rate, s
1582 Specify the sample rate, default to 44100. Only used if plugin have
1586 Set the number of samples per channel per each output frame, default
1587 is 1024. Only used if plugin have zero inputs.
1590 Set the minimum duration of the sourced audio. See the function
1591 @code{av_parse_time()} for the accepted format, also check the "Time duration"
1592 section in the ffmpeg-utils manual.
1593 Note that the resulting duration may be greater than the specified duration,
1594 as the generated audio is always cut at the end of a complete frame.
1595 If not specified, or the expressed duration is negative, the audio is
1596 supposed to be generated forever.
1597 Only used if plugin have zero inputs.
1601 @subsection Examples
1605 List all available plugins within amp (LADSPA example plugin) library:
1611 List all available controls and their valid ranges for @code{vcf_notch}
1612 plugin from @code{VCF} library:
1614 ladspa=f=vcf:p=vcf_notch:c=help
1618 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1621 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1625 Add reverberation to the audio using TAP-plugins
1626 (Tom's Audio Processing plugins):
1628 ladspa=file=tap_reverb:tap_reverb
1632 Generate white noise, with 0.2 amplitude:
1634 ladspa=file=cmt:noise_source_white:c=c0=.2
1638 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1639 @code{C* Audio Plugin Suite} (CAPS) library:
1641 ladspa=file=caps:Click:c=c1=20'
1645 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1647 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1651 @subsection Commands
1653 This filter supports the following commands:
1656 Modify the @var{N}-th control value.
1658 If the specified value is not valid, it is ignored and prior one is kept.
1663 Apply a low-pass filter with 3dB point frequency.
1664 The filter can be either single-pole or double-pole (the default).
1665 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1667 The filter accepts the following options:
1671 Set frequency in Hz. Default is 500.
1674 Set number of poles. Default is 2.
1677 Set method to specify band-width of filter.
1690 Specify the band-width of a filter in width_type units.
1691 Applies only to double-pole filter.
1692 The default is 0.707q and gives a Butterworth response.
1697 Mix channels with specific gain levels. The filter accepts the output
1698 channel layout followed by a set of channels definitions.
1700 This filter is also designed to remap efficiently the channels of an audio
1703 The filter accepts parameters of the form:
1704 "@var{l}:@var{outdef}:@var{outdef}:..."
1708 output channel layout or number of channels
1711 output channel specification, of the form:
1712 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1715 output channel to define, either a channel name (FL, FR, etc.) or a channel
1716 number (c0, c1, etc.)
1719 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1722 input channel to use, see out_name for details; it is not possible to mix
1723 named and numbered input channels
1726 If the `=' in a channel specification is replaced by `<', then the gains for
1727 that specification will be renormalized so that the total is 1, thus
1728 avoiding clipping noise.
1730 @subsection Mixing examples
1732 For example, if you want to down-mix from stereo to mono, but with a bigger
1733 factor for the left channel:
1735 pan=1:c0=0.9*c0+0.1*c1
1738 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1739 7-channels surround:
1741 pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1744 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1745 that should be preferred (see "-ac" option) unless you have very specific
1748 @subsection Remapping examples
1750 The channel remapping will be effective if, and only if:
1753 @item gain coefficients are zeroes or ones,
1754 @item only one input per channel output,
1757 If all these conditions are satisfied, the filter will notify the user ("Pure
1758 channel mapping detected"), and use an optimized and lossless method to do the
1761 For example, if you have a 5.1 source and want a stereo audio stream by
1762 dropping the extra channels:
1764 pan="stereo: c0=FL : c1=FR"
1767 Given the same source, you can also switch front left and front right channels
1768 and keep the input channel layout:
1770 pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
1773 If the input is a stereo audio stream, you can mute the front left channel (and
1774 still keep the stereo channel layout) with:
1779 Still with a stereo audio stream input, you can copy the right channel in both
1780 front left and right:
1782 pan="stereo: c0=FR : c1=FR"
1787 ReplayGain scanner filter. This filter takes an audio stream as an input and
1788 outputs it unchanged.
1789 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1793 Convert the audio sample format, sample rate and channel layout. It is
1794 not meant to be used directly.
1796 @section silencedetect
1798 Detect silence in an audio stream.
1800 This filter logs a message when it detects that the input audio volume is less
1801 or equal to a noise tolerance value for a duration greater or equal to the
1802 minimum detected noise duration.
1804 The printed times and duration are expressed in seconds.
1806 The filter accepts the following options:
1810 Set silence duration until notification (default is 2 seconds).
1813 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1814 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1817 @subsection Examples
1821 Detect 5 seconds of silence with -50dB noise tolerance:
1823 silencedetect=n=-50dB:d=5
1827 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1828 tolerance in @file{silence.mp3}:
1830 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1836 Boost or cut treble (upper) frequencies of the audio using a two-pole
1837 shelving filter with a response similar to that of a standard
1838 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1840 The filter accepts the following options:
1844 Give the gain at whichever is the lower of ~22 kHz and the
1845 Nyquist frequency. Its useful range is about -20 (for a large cut)
1846 to +20 (for a large boost). Beware of clipping when using a positive gain.
1849 Set the filter's central frequency and so can be used
1850 to extend or reduce the frequency range to be boosted or cut.
1851 The default value is @code{3000} Hz.
1854 Set method to specify band-width of filter.
1867 Determine how steep is the filter's shelf transition.
1872 Adjust the input audio volume.
1874 It accepts the following parameters:
1878 Set audio volume expression.
1880 Output values are clipped to the maximum value.
1882 The output audio volume is given by the relation:
1884 @var{output_volume} = @var{volume} * @var{input_volume}
1887 The default value for @var{volume} is "1.0".
1890 This parameter represents the mathematical precision.
1892 It determines which input sample formats will be allowed, which affects the
1893 precision of the volume scaling.
1897 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
1899 32-bit floating-point; this limits input sample format to FLT. (default)
1901 64-bit floating-point; this limits input sample format to DBL.
1905 Choose the behaviour on encountering ReplayGain side data in input frames.
1909 Remove ReplayGain side data, ignoring its contents (the default).
1912 Ignore ReplayGain side data, but leave it in the frame.
1915 Prefer the track gain, if present.
1918 Prefer the album gain, if present.
1921 @item replaygain_preamp
1922 Pre-amplification gain in dB to apply to the selected replaygain gain.
1924 Default value for @var{replaygain_preamp} is 0.0.
1927 Set when the volume expression is evaluated.
1929 It accepts the following values:
1932 only evaluate expression once during the filter initialization, or
1933 when the @samp{volume} command is sent
1936 evaluate expression for each incoming frame
1939 Default value is @samp{once}.
1942 The volume expression can contain the following parameters.
1946 frame number (starting at zero)
1949 @item nb_consumed_samples
1950 number of samples consumed by the filter
1952 number of samples in the current frame
1954 original frame position in the file
1960 PTS at start of stream
1962 time at start of stream
1968 last set volume value
1971 Note that when @option{eval} is set to @samp{once} only the
1972 @var{sample_rate} and @var{tb} variables are available, all other
1973 variables will evaluate to NAN.
1975 @subsection Commands
1977 This filter supports the following commands:
1980 Modify the volume expression.
1981 The command accepts the same syntax of the corresponding option.
1983 If the specified expression is not valid, it is kept at its current
1985 @item replaygain_noclip
1986 Prevent clipping by limiting the gain applied.
1988 Default value for @var{replaygain_noclip} is 1.
1992 @subsection Examples
1996 Halve the input audio volume:
2000 volume=volume=-6.0206dB
2003 In all the above example the named key for @option{volume} can be
2004 omitted, for example like in:
2010 Increase input audio power by 6 decibels using fixed-point precision:
2012 volume=volume=6dB:precision=fixed
2016 Fade volume after time 10 with an annihilation period of 5 seconds:
2018 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
2022 @section volumedetect
2024 Detect the volume of the input video.
2026 The filter has no parameters. The input is not modified. Statistics about
2027 the volume will be printed in the log when the input stream end is reached.
2029 In particular it will show the mean volume (root mean square), maximum
2030 volume (on a per-sample basis), and the beginning of a histogram of the
2031 registered volume values (from the maximum value to a cumulated 1/1000 of
2034 All volumes are in decibels relative to the maximum PCM value.
2036 @subsection Examples
2038 Here is an excerpt of the output:
2040 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2041 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2042 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2043 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2044 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2045 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2046 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2047 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2048 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2054 The mean square energy is approximately -27 dB, or 10^-2.7.
2056 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2058 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2061 In other words, raising the volume by +4 dB does not cause any clipping,
2062 raising it by +5 dB causes clipping for 6 samples, etc.
2064 @c man end AUDIO FILTERS
2066 @chapter Audio Sources
2067 @c man begin AUDIO SOURCES
2069 Below is a description of the currently available audio sources.
2073 Buffer audio frames, and make them available to the filter chain.
2075 This source is mainly intended for a programmatic use, in particular
2076 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2078 It accepts the following parameters:
2082 The timebase which will be used for timestamps of submitted frames. It must be
2083 either a floating-point number or in @var{numerator}/@var{denominator} form.
2086 The sample rate of the incoming audio buffers.
2089 The sample format of the incoming audio buffers.
2090 Either a sample format name or its corresponging integer representation from
2091 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2093 @item channel_layout
2094 The channel layout of the incoming audio buffers.
2095 Either a channel layout name from channel_layout_map in
2096 @file{libavutil/channel_layout.c} or its corresponding integer representation
2097 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2100 The number of channels of the incoming audio buffers.
2101 If both @var{channels} and @var{channel_layout} are specified, then they
2106 @subsection Examples
2109 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2112 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2113 Since the sample format with name "s16p" corresponds to the number
2114 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2117 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2122 Generate an audio signal specified by an expression.
2124 This source accepts in input one or more expressions (one for each
2125 channel), which are evaluated and used to generate a corresponding
2128 This source accepts the following options:
2132 Set the '|'-separated expressions list for each separate channel. In case the
2133 @option{channel_layout} option is not specified, the selected channel layout
2134 depends on the number of provided expressions. Otherwise the last
2135 specified expression is applied to the remaining output channels.
2137 @item channel_layout, c
2138 Set the channel layout. The number of channels in the specified layout
2139 must be equal to the number of specified expressions.
2142 Set the minimum duration of the sourced audio. See the function
2143 @code{av_parse_time()} for the accepted format.
2144 Note that the resulting duration may be greater than the specified
2145 duration, as the generated audio is always cut at the end of a
2148 If not specified, or the expressed duration is negative, the audio is
2149 supposed to be generated forever.
2152 Set the number of samples per channel per each output frame,
2155 @item sample_rate, s
2156 Specify the sample rate, default to 44100.
2159 Each expression in @var{exprs} can contain the following constants:
2163 number of the evaluated sample, starting from 0
2166 time of the evaluated sample expressed in seconds, starting from 0
2173 @subsection Examples
2183 Generate a sin signal with frequency of 440 Hz, set sample rate to
2186 aevalsrc="sin(440*2*PI*t):s=8000"
2190 Generate a two channels signal, specify the channel layout (Front
2191 Center + Back Center) explicitly:
2193 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2197 Generate white noise:
2199 aevalsrc="-2+random(0)"
2203 Generate an amplitude modulated signal:
2205 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2209 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2211 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2218 The null audio source, return unprocessed audio frames. It is mainly useful
2219 as a template and to be employed in analysis / debugging tools, or as
2220 the source for filters which ignore the input data (for example the sox
2223 This source accepts the following options:
2227 @item channel_layout, cl
2229 Specifies the channel layout, and can be either an integer or a string
2230 representing a channel layout. The default value of @var{channel_layout}
2233 Check the channel_layout_map definition in
2234 @file{libavutil/channel_layout.c} for the mapping between strings and
2235 channel layout values.
2237 @item sample_rate, r
2238 Specifies the sample rate, and defaults to 44100.
2241 Set the number of samples per requested frames.
2245 @subsection Examples
2249 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2251 anullsrc=r=48000:cl=4
2255 Do the same operation with a more obvious syntax:
2257 anullsrc=r=48000:cl=mono
2261 All the parameters need to be explicitly defined.
2265 Synthesize a voice utterance using the libflite library.
2267 To enable compilation of this filter you need to configure FFmpeg with
2268 @code{--enable-libflite}.
2270 Note that the flite library is not thread-safe.
2272 The filter accepts the following options:
2277 If set to 1, list the names of the available voices and exit
2278 immediately. Default value is 0.
2281 Set the maximum number of samples per frame. Default value is 512.
2284 Set the filename containing the text to speak.
2287 Set the text to speak.
2290 Set the voice to use for the speech synthesis. Default value is
2291 @code{kal}. See also the @var{list_voices} option.
2294 @subsection Examples
2298 Read from file @file{speech.txt}, and synthetize the text using the
2299 standard flite voice:
2301 flite=textfile=speech.txt
2305 Read the specified text selecting the @code{slt} voice:
2307 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2311 Input text to ffmpeg:
2313 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2317 Make @file{ffplay} speak the specified text, using @code{flite} and
2318 the @code{lavfi} device:
2320 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2324 For more information about libflite, check:
2325 @url{http://www.speech.cs.cmu.edu/flite/}
2329 Generate an audio signal made of a sine wave with amplitude 1/8.
2331 The audio signal is bit-exact.
2333 The filter accepts the following options:
2338 Set the carrier frequency. Default is 440 Hz.
2340 @item beep_factor, b
2341 Enable a periodic beep every second with frequency @var{beep_factor} times
2342 the carrier frequency. Default is 0, meaning the beep is disabled.
2344 @item sample_rate, r
2345 Specify the sample rate, default is 44100.
2348 Specify the duration of the generated audio stream.
2350 @item samples_per_frame
2351 Set the number of samples per output frame, default is 1024.
2354 @subsection Examples
2359 Generate a simple 440 Hz sine wave:
2365 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2369 sine=frequency=220:beep_factor=4:duration=5
2374 @c man end AUDIO SOURCES
2376 @chapter Audio Sinks
2377 @c man begin AUDIO SINKS
2379 Below is a description of the currently available audio sinks.
2381 @section abuffersink
2383 Buffer audio frames, and make them available to the end of filter chain.
2385 This sink is mainly intended for programmatic use, in particular
2386 through the interface defined in @file{libavfilter/buffersink.h}
2387 or the options system.
2389 It accepts a pointer to an AVABufferSinkContext structure, which
2390 defines the incoming buffers' formats, to be passed as the opaque
2391 parameter to @code{avfilter_init_filter} for initialization.
2394 Null audio sink; do absolutely nothing with the input audio. It is
2395 mainly useful as a template and for use in analysis / debugging
2398 @c man end AUDIO SINKS
2400 @chapter Video Filters
2401 @c man begin VIDEO FILTERS
2403 When you configure your FFmpeg build, you can disable any of the
2404 existing filters using @code{--disable-filters}.
2405 The configure output will show the video filters included in your
2408 Below is a description of the currently available video filters.
2410 @section alphaextract
2412 Extract the alpha component from the input as a grayscale video. This
2413 is especially useful with the @var{alphamerge} filter.
2417 Add or replace the alpha component of the primary input with the
2418 grayscale value of a second input. This is intended for use with
2419 @var{alphaextract} to allow the transmission or storage of frame
2420 sequences that have alpha in a format that doesn't support an alpha
2423 For example, to reconstruct full frames from a normal YUV-encoded video
2424 and a separate video created with @var{alphaextract}, you might use:
2426 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2429 Since this filter is designed for reconstruction, it operates on frame
2430 sequences without considering timestamps, and terminates when either
2431 input reaches end of stream. This will cause problems if your encoding
2432 pipeline drops frames. If you're trying to apply an image as an
2433 overlay to a video stream, consider the @var{overlay} filter instead.
2437 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2438 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2439 Substation Alpha) subtitles files.
2443 Compute the bounding box for the non-black pixels in the input frame
2446 This filter computes the bounding box containing all the pixels with a
2447 luminance value greater than the minimum allowed value.
2448 The parameters describing the bounding box are printed on the filter
2451 The filter accepts the following option:
2455 Set the minimal luminance value. Default is @code{16}.
2458 @section blackdetect
2460 Detect video intervals that are (almost) completely black. Can be
2461 useful to detect chapter transitions, commercials, or invalid
2462 recordings. Output lines contains the time for the start, end and
2463 duration of the detected black interval expressed in seconds.
2465 In order to display the output lines, you need to set the loglevel at
2466 least to the AV_LOG_INFO value.
2468 The filter accepts the following options:
2471 @item black_min_duration, d
2472 Set the minimum detected black duration expressed in seconds. It must
2473 be a non-negative floating point number.
2475 Default value is 2.0.
2477 @item picture_black_ratio_th, pic_th
2478 Set the threshold for considering a picture "black".
2479 Express the minimum value for the ratio:
2481 @var{nb_black_pixels} / @var{nb_pixels}
2484 for which a picture is considered black.
2485 Default value is 0.98.
2487 @item pixel_black_th, pix_th
2488 Set the threshold for considering a pixel "black".
2490 The threshold expresses the maximum pixel luminance value for which a
2491 pixel is considered "black". The provided value is scaled according to
2492 the following equation:
2494 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2497 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2498 the input video format, the range is [0-255] for YUV full-range
2499 formats and [16-235] for YUV non full-range formats.
2501 Default value is 0.10.
2504 The following example sets the maximum pixel threshold to the minimum
2505 value, and detects only black intervals of 2 or more seconds:
2507 blackdetect=d=2:pix_th=0.00
2512 Detect frames that are (almost) completely black. Can be useful to
2513 detect chapter transitions or commercials. Output lines consist of
2514 the frame number of the detected frame, the percentage of blackness,
2515 the position in the file if known or -1 and the timestamp in seconds.
2517 In order to display the output lines, you need to set the loglevel at
2518 least to the AV_LOG_INFO value.
2520 It accepts the following parameters:
2525 The percentage of the pixels that have to be below the threshold; it defaults to
2528 @item threshold, thresh
2529 The threshold below which a pixel value is considered black; it defaults to
2536 Blend two video frames into each other.
2538 It takes two input streams and outputs one stream, the first input is the
2539 "top" layer and second input is "bottom" layer.
2540 Output terminates when shortest input terminates.
2542 A description of the accepted options follows.
2550 Set blend mode for specific pixel component or all pixel components in case
2551 of @var{all_mode}. Default value is @code{normal}.
2553 Available values for component modes are:
2586 Set blend opacity for specific pixel component or all pixel components in case
2587 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2594 Set blend expression for specific pixel component or all pixel components in case
2595 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2597 The expressions can use the following variables:
2601 The sequential number of the filtered frame, starting from @code{0}.
2605 the coordinates of the current sample
2609 the width and height of currently filtered plane
2613 Width and height scale depending on the currently filtered plane. It is the
2614 ratio between the corresponding luma plane number of pixels and the current
2615 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2616 @code{0.5,0.5} for chroma planes.
2619 Time of the current frame, expressed in seconds.
2622 Value of pixel component at current location for first video frame (top layer).
2625 Value of pixel component at current location for second video frame (bottom layer).
2629 Force termination when the shortest input terminates. Default is @code{0}.
2631 Continue applying the last bottom frame after the end of the stream. A value of
2632 @code{0} disable the filter after the last frame of the bottom layer is reached.
2633 Default is @code{1}.
2636 @subsection Examples
2640 Apply transition from bottom layer to top layer in first 10 seconds:
2642 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2646 Apply 1x1 checkerboard effect:
2648 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2652 Apply uncover left effect:
2654 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2658 Apply uncover down effect:
2660 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2664 Apply uncover up-left effect:
2666 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2672 Apply a boxblur algorithm to the input video.
2674 It accepts the following parameters:
2678 @item luma_radius, lr
2679 @item luma_power, lp
2680 @item chroma_radius, cr
2681 @item chroma_power, cp
2682 @item alpha_radius, ar
2683 @item alpha_power, ap
2687 A description of the accepted options follows.
2690 @item luma_radius, lr
2691 @item chroma_radius, cr
2692 @item alpha_radius, ar
2693 Set an expression for the box radius in pixels used for blurring the
2694 corresponding input plane.
2696 The radius value must be a non-negative number, and must not be
2697 greater than the value of the expression @code{min(w,h)/2} for the
2698 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2701 Default value for @option{luma_radius} is "2". If not specified,
2702 @option{chroma_radius} and @option{alpha_radius} default to the
2703 corresponding value set for @option{luma_radius}.
2705 The expressions can contain the following constants:
2709 The input width and height in pixels.
2713 The input chroma image width and height in pixels.
2717 The horizontal and vertical chroma subsample values. For example, for the
2718 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
2721 @item luma_power, lp
2722 @item chroma_power, cp
2723 @item alpha_power, ap
2724 Specify how many times the boxblur filter is applied to the
2725 corresponding plane.
2727 Default value for @option{luma_power} is 2. If not specified,
2728 @option{chroma_power} and @option{alpha_power} default to the
2729 corresponding value set for @option{luma_power}.
2731 A value of 0 will disable the effect.
2734 @subsection Examples
2738 Apply a boxblur filter with the luma, chroma, and alpha radii
2741 boxblur=luma_radius=2:luma_power=1
2746 Set the luma radius to 2, and alpha and chroma radius to 0:
2748 boxblur=2:1:cr=0:ar=0
2752 Set the luma and chroma radii to a fraction of the video dimension:
2754 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2758 @section colorbalance
2759 Modify intensity of primary colors (red, green and blue) of input frames.
2761 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2762 regions for the red-cyan, green-magenta or blue-yellow balance.
2764 A positive adjustment value shifts the balance towards the primary color, a negative
2765 value towards the complementary color.
2767 The filter accepts the following options:
2773 Adjust red, green and blue shadows (darkest pixels).
2778 Adjust red, green and blue midtones (medium pixels).
2783 Adjust red, green and blue highlights (brightest pixels).
2785 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2788 @subsection Examples
2792 Add red color cast to shadows:
2798 @section colorchannelmixer
2800 Adjust video input frames by re-mixing color channels.
2802 This filter modifies a color channel by adding the values associated to
2803 the other channels of the same pixels. For example if the value to
2804 modify is red, the output value will be:
2806 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2809 The filter accepts the following options:
2816 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2817 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2823 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2824 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2830 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2831 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2837 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2838 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2840 Allowed ranges for options are @code{[-2.0, 2.0]}.
2843 @subsection Examples
2847 Convert source to grayscale:
2849 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2852 Simulate sepia tones:
2854 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
2858 @section colormatrix
2860 Convert color matrix.
2862 The filter accepts the following options:
2867 Specify the source and destination color matrix. Both values must be
2870 The accepted values are:
2886 For example to convert from BT.601 to SMPTE-240M, use the command:
2888 colormatrix=bt601:smpte240m
2893 Copy the input source unchanged to the output. This is mainly useful for
2898 Crop the input video to given dimensions.
2900 It accepts the following parameters:
2904 The width of the output video. It defaults to @code{iw}.
2905 This expression is evaluated only once during the filter
2909 The height of the output video. It defaults to @code{ih}.
2910 This expression is evaluated only once during the filter
2914 The horizontal position, in the input video, of the left edge of the output
2915 video. It defaults to @code{(in_w-out_w)/2}.
2916 This expression is evaluated per-frame.
2919 The vertical position, in the input video, of the top edge of the output video.
2920 It defaults to @code{(in_h-out_h)/2}.
2921 This expression is evaluated per-frame.
2924 If set to 1 will force the output display aspect ratio
2925 to be the same of the input, by changing the output sample aspect
2926 ratio. It defaults to 0.
2929 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
2930 expressions containing the following constants:
2935 The computed values for @var{x} and @var{y}. They are evaluated for
2940 The input width and height.
2944 These are the same as @var{in_w} and @var{in_h}.
2948 The output (cropped) width and height.
2952 These are the same as @var{out_w} and @var{out_h}.
2955 same as @var{iw} / @var{ih}
2958 input sample aspect ratio
2961 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
2965 horizontal and vertical chroma subsample values. For example for the
2966 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2969 The number of the input frame, starting from 0.
2972 the position in the file of the input frame, NAN if unknown
2975 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
2979 The expression for @var{out_w} may depend on the value of @var{out_h},
2980 and the expression for @var{out_h} may depend on @var{out_w}, but they
2981 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
2982 evaluated after @var{out_w} and @var{out_h}.
2984 The @var{x} and @var{y} parameters specify the expressions for the
2985 position of the top-left corner of the output (non-cropped) area. They
2986 are evaluated for each frame. If the evaluated value is not valid, it
2987 is approximated to the nearest valid value.
2989 The expression for @var{x} may depend on @var{y}, and the expression
2990 for @var{y} may depend on @var{x}.
2992 @subsection Examples
2996 Crop area with size 100x100 at position (12,34).
3001 Using named options, the example above becomes:
3003 crop=w=100:h=100:x=12:y=34
3007 Crop the central input area with size 100x100:
3013 Crop the central input area with size 2/3 of the input video:
3015 crop=2/3*in_w:2/3*in_h
3019 Crop the input video central square:
3026 Delimit the rectangle with the top-left corner placed at position
3027 100:100 and the right-bottom corner corresponding to the right-bottom
3028 corner of the input image.
3030 crop=in_w-100:in_h-100:100:100
3034 Crop 10 pixels from the left and right borders, and 20 pixels from
3035 the top and bottom borders
3037 crop=in_w-2*10:in_h-2*20
3041 Keep only the bottom right quarter of the input image:
3043 crop=in_w/2:in_h/2:in_w/2:in_h/2
3047 Crop height for getting Greek harmony:
3049 crop=in_w:1/PHI*in_w
3053 Appply trembling effect:
3055 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)
3059 Apply erratic camera effect depending on timestamp:
3061 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)"
3065 Set x depending on the value of y:
3067 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3073 Auto-detect the crop size.
3075 It calculates the necessary cropping parameters and prints the
3076 recommended parameters via the logging system. The detected dimensions
3077 correspond to the non-black area of the input video.
3079 It accepts the following parameters:
3084 Set higher black value threshold, which can be optionally specified
3085 from nothing (0) to everything (255). An intensity value greater
3086 to the set value is considered non-black. It defaults to 24.
3089 The value which the width/height should be divisible by. It defaults to
3090 16. The offset is automatically adjusted to center the video. Use 2 to
3091 get only even dimensions (needed for 4:2:2 video). 16 is best when
3092 encoding to most video codecs.
3094 @item reset_count, reset
3095 Set the counter that determines after how many frames cropdetect will
3096 reset the previously detected largest video area and start over to
3097 detect the current optimal crop area. Default value is 0.
3099 This can be useful when channel logos distort the video area. 0
3100 indicates 'never reset', and returns the largest area encountered during
3107 Apply color adjustments using curves.
3109 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3110 component (red, green and blue) has its values defined by @var{N} key points
3111 tied from each other using a smooth curve. The x-axis represents the pixel
3112 values from the input frame, and the y-axis the new pixel values to be set for
3115 By default, a component curve is defined by the two points @var{(0;0)} and
3116 @var{(1;1)}. This creates a straight line where each original pixel value is
3117 "adjusted" to its own value, which means no change to the image.
3119 The filter allows you to redefine these two points and add some more. A new
3120 curve (using a natural cubic spline interpolation) will be define to pass
3121 smoothly through all these new coordinates. The new defined points needs to be
3122 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3123 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3124 the vector spaces, the values will be clipped accordingly.
3126 If there is no key point defined in @code{x=0}, the filter will automatically
3127 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3128 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3130 The filter accepts the following options:
3134 Select one of the available color presets. This option can be used in addition
3135 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3136 options takes priority on the preset values.
3137 Available presets are:
3140 @item color_negative
3143 @item increase_contrast
3145 @item linear_contrast
3146 @item medium_contrast
3148 @item strong_contrast
3151 Default is @code{none}.
3153 Set the master key points. These points will define a second pass mapping. It
3154 is sometimes called a "luminance" or "value" mapping. It can be used with
3155 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3156 post-processing LUT.
3158 Set the key points for the red component.
3160 Set the key points for the green component.
3162 Set the key points for the blue component.
3164 Set the key points for all components (not including master).
3165 Can be used in addition to the other key points component
3166 options. In this case, the unset component(s) will fallback on this
3167 @option{all} setting.
3169 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3172 To avoid some filtergraph syntax conflicts, each key points list need to be
3173 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3175 @subsection Examples
3179 Increase slightly the middle level of blue:
3181 curves=blue='0.5/0.58'
3187 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3189 Here we obtain the following coordinates for each components:
3192 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3194 @code{(0;0) (0.50;0.48) (1;1)}
3196 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3200 The previous example can also be achieved with the associated built-in preset:
3202 curves=preset=vintage
3212 Use a Photoshop preset and redefine the points of the green component:
3214 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3220 Denoise frames using 2D DCT (frequency domain filtering).
3222 This filter is not designed for real time and can be extremely slow.
3224 The filter accepts the following options:
3228 Set the noise sigma constant.
3230 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3231 coefficient (absolute value) below this threshold with be dropped.
3233 If you need a more advanced filtering, see @option{expr}.
3235 Default is @code{0}.
3238 Set number overlapping pixels for each block. Each block is of size
3239 @code{16x16}. Since the filter can be slow, you may want to reduce this value,
3240 at the cost of a less effective filter and the risk of various artefacts.
3242 If the overlapping value doesn't allow to process the whole input width or
3243 height, a warning will be displayed and according borders won't be denoised.
3245 Default value is @code{15}.
3248 Set the coefficient factor expression.
3250 For each coefficient of a DCT block, this expression will be evaluated as a
3251 multiplier value for the coefficient.
3253 If this is option is set, the @option{sigma} option will be ignored.
3255 The absolute value of the coefficient can be accessed through the @var{c}
3259 @subsection Examples
3261 Apply a denoise with a @option{sigma} of @code{4.5}:
3266 The same operation can be achieved using the expression system:
3268 dctdnoiz=e='gte(c, 4.5*3)'
3274 Drop duplicated frames at regular intervals.
3276 The filter accepts the following options:
3280 Set the number of frames from which one will be dropped. Setting this to
3281 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3282 Default is @code{5}.
3285 Set the threshold for duplicate detection. If the difference metric for a frame
3286 is less than or equal to this value, then it is declared as duplicate. Default
3290 Set scene change threshold. Default is @code{15}.
3294 Set the size of the x and y-axis blocks used during metric calculations.
3295 Larger blocks give better noise suppression, but also give worse detection of
3296 small movements. Must be a power of two. Default is @code{32}.
3299 Mark main input as a pre-processed input and activate clean source input
3300 stream. This allows the input to be pre-processed with various filters to help
3301 the metrics calculation while keeping the frame selection lossless. When set to
3302 @code{1}, the first stream is for the pre-processed input, and the second
3303 stream is the clean source from where the kept frames are chosen. Default is
3307 Set whether or not chroma is considered in the metric calculations. Default is
3313 Remove judder produced by partially interlaced telecined content.
3315 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3316 source was partially telecined content then the output of @code{pullup,dejudder}
3317 will have a variable frame rate. May change the recorded frame rate of the
3318 container. Aside from that change, this filter will not affect constant frame
3321 The option available in this filter is:
3325 Specify the length of the window over which the judder repeats.
3327 Accepts any integer greater than 1. Useful values are:
3331 If the original was telecined from 24 to 30 fps (Film to NTSC).
3334 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3337 If a mixture of the two.
3340 The default is @samp{4}.
3345 Suppress a TV station logo by a simple interpolation of the surrounding
3346 pixels. Just set a rectangle covering the logo and watch it disappear
3347 (and sometimes something even uglier appear - your mileage may vary).
3349 It accepts the following parameters:
3354 Specify the top left corner coordinates of the logo. They must be
3359 Specify the width and height of the logo to clear. They must be
3363 Specify the thickness of the fuzzy edge of the rectangle (added to
3364 @var{w} and @var{h}). The default value is 4.
3367 When set to 1, a green rectangle is drawn on the screen to simplify
3368 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3369 The default value is 0.
3371 The rectangle is drawn on the outermost pixels which will be (partly)
3372 replaced with interpolated values. The values of the next pixels
3373 immediately outside this rectangle in each direction will be used to
3374 compute the interpolated pixel values inside the rectangle.
3378 @subsection Examples
3382 Set a rectangle covering the area with top left corner coordinates 0,0
3383 and size 100x77, and a band of size 10:
3385 delogo=x=0:y=0:w=100:h=77:band=10
3392 Attempt to fix small changes in horizontal and/or vertical shift. This
3393 filter helps remove camera shake from hand-holding a camera, bumping a
3394 tripod, moving on a vehicle, etc.
3396 The filter accepts the following options:
3404 Specify a rectangular area where to limit the search for motion
3406 If desired the search for motion vectors can be limited to a
3407 rectangular area of the frame defined by its top left corner, width
3408 and height. These parameters have the same meaning as the drawbox
3409 filter which can be used to visualise the position of the bounding
3412 This is useful when simultaneous movement of subjects within the frame
3413 might be confused for camera motion by the motion vector search.
3415 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3416 then the full frame is used. This allows later options to be set
3417 without specifying the bounding box for the motion vector search.
3419 Default - search the whole frame.
3423 Specify the maximum extent of movement in x and y directions in the
3424 range 0-64 pixels. Default 16.
3427 Specify how to generate pixels to fill blanks at the edge of the
3428 frame. Available values are:
3431 Fill zeroes at blank locations
3433 Original image at blank locations
3435 Extruded edge value at blank locations
3437 Mirrored edge at blank locations
3439 Default value is @samp{mirror}.
3442 Specify the blocksize to use for motion search. Range 4-128 pixels,
3446 Specify the contrast threshold for blocks. Only blocks with more than
3447 the specified contrast (difference between darkest and lightest
3448 pixels) will be considered. Range 1-255, default 125.
3451 Specify the search strategy. Available values are:
3454 Set exhaustive search
3456 Set less exhaustive search.
3458 Default value is @samp{exhaustive}.
3461 If set then a detailed log of the motion search is written to the
3465 If set to 1, specify using OpenCL capabilities, only available if
3466 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3472 Draw a colored box on the input image.
3474 It accepts the following parameters:
3479 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3483 The expressions which specify the width and height of the box; if 0 they are interpreted as
3484 the input width and height. It defaults to 0.
3487 Specify the color of the box to write. For the general syntax of this option,
3488 check the "Color" section in the ffmpeg-utils manual. If the special
3489 value @code{invert} is used, the box edge color is the same as the
3490 video with inverted luma.
3493 The expression which sets the thickness of the box edge. Default value is @code{3}.
3495 See below for the list of accepted constants.
3498 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3499 following constants:
3503 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3507 horizontal and vertical chroma subsample values. For example for the
3508 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3512 The input width and height.
3515 The input sample aspect ratio.
3519 The x and y offset coordinates where the box is drawn.
3523 The width and height of the drawn box.
3526 The thickness of the drawn box.
3528 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3529 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3533 @subsection Examples
3537 Draw a black box around the edge of the input image:
3543 Draw a box with color red and an opacity of 50%:
3545 drawbox=10:20:200:60:red@@0.5
3548 The previous example can be specified as:
3550 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3554 Fill the box with pink color:
3556 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3560 Draw a 2-pixel red 2.40:1 mask:
3562 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
3568 Draw a grid on the input image.
3570 It accepts the following parameters:
3575 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3579 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3580 input width and height, respectively, minus @code{thickness}, so image gets
3581 framed. Default to 0.
3584 Specify the color of the grid. For the general syntax of this option,
3585 check the "Color" section in the ffmpeg-utils manual. If the special
3586 value @code{invert} is used, the grid color is the same as the
3587 video with inverted luma.
3590 The expression which sets the thickness of the grid line. Default value is @code{1}.
3592 See below for the list of accepted constants.
3595 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3596 following constants:
3600 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3604 horizontal and vertical chroma subsample values. For example for the
3605 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3609 The input grid cell width and height.
3612 The input sample aspect ratio.
3616 The x and y coordinates of some point of grid intersection (meant to configure offset).
3620 The width and height of the drawn cell.
3623 The thickness of the drawn cell.
3625 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3626 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3630 @subsection Examples
3634 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3636 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3640 Draw a white 3x3 grid with an opacity of 50%:
3642 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3649 Draw a text string or text from a specified file on top of a video, using the
3650 libfreetype library.
3652 To enable compilation of this filter, you need to configure FFmpeg with
3653 @code{--enable-libfreetype}.
3654 To enable default font fallback and the @var{font} option you need to
3655 configure FFmpeg with @code{--enable-libfontconfig}.
3656 To enable the @var{text_shaping} option, you need to configure FFmpeg with
3657 @code{--enable-libfribidi}.
3661 It accepts the following parameters:
3666 Used to draw a box around text using the background color.
3667 The value must be either 1 (enable) or 0 (disable).
3668 The default value of @var{box} is 0.
3671 The color to be used for drawing box around text. For the syntax of this
3672 option, check the "Color" section in the ffmpeg-utils manual.
3674 The default value of @var{boxcolor} is "white".
3677 Set the width of the border to be drawn around the text using @var{bordercolor}.
3678 The default value of @var{borderw} is 0.
3681 Set the color to be used for drawing border around text. For the syntax of this
3682 option, check the "Color" section in the ffmpeg-utils manual.
3684 The default value of @var{bordercolor} is "black".
3687 Select how the @var{text} is expanded. Can be either @code{none},
3688 @code{strftime} (deprecated) or
3689 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3693 If true, check and fix text coords to avoid clipping.
3696 The color to be used for drawing fonts. For the syntax of this option, check
3697 the "Color" section in the ffmpeg-utils manual.
3699 The default value of @var{fontcolor} is "black".
3701 @item fontcolor_expr
3702 String which is expanded the same way as @var{text} to obtain dynamic
3703 @var{fontcolor} value. By default this option has empty value and is not
3704 processed. When this option is set, it overrides @var{fontcolor} option.
3707 The font family to be used for drawing text. By default Sans.
3710 The font file to be used for drawing text. The path must be included.
3711 This parameter is mandatory if the fontconfig support is disabled.
3714 The font size to be used for drawing text.
3715 The default value of @var{fontsize} is 16.
3718 If set to 1, attempt to shape the text (for example, reverse the order of
3719 right-to-left text and join Arabic characters) before drawing it.
3720 Otherwise, just draw the text exactly as given.
3721 By default 1 (if supported).
3724 The flags to be used for loading the fonts.
3726 The flags map the corresponding flags supported by libfreetype, and are
3727 a combination of the following values:
3734 @item vertical_layout
3735 @item force_autohint
3738 @item ignore_global_advance_width
3740 @item ignore_transform
3746 Default value is "default".
3748 For more information consult the documentation for the FT_LOAD_*
3752 The color to be used for drawing a shadow behind the drawn text. For the
3753 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3755 The default value of @var{shadowcolor} is "black".
3759 The x and y offsets for the text shadow position with respect to the
3760 position of the text. They can be either positive or negative
3761 values. The default value for both is "0".
3764 The starting frame number for the n/frame_num variable. The default value
3768 The size in number of spaces to use for rendering the tab.
3772 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3773 format. It can be used with or without text parameter. @var{timecode_rate}
3774 option must be specified.
3776 @item timecode_rate, rate, r
3777 Set the timecode frame rate (timecode only).
3780 The text string to be drawn. The text must be a sequence of UTF-8
3782 This parameter is mandatory if no file is specified with the parameter
3786 A text file containing text to be drawn. The text must be a sequence
3787 of UTF-8 encoded characters.
3789 This parameter is mandatory if no text string is specified with the
3790 parameter @var{text}.
3792 If both @var{text} and @var{textfile} are specified, an error is thrown.
3795 If set to 1, the @var{textfile} will be reloaded before each frame.
3796 Be sure to update it atomically, or it may be read partially, or even fail.
3800 The expressions which specify the offsets where text will be drawn
3801 within the video frame. They are relative to the top/left border of the
3804 The default value of @var{x} and @var{y} is "0".
3806 See below for the list of accepted constants and functions.
3809 The parameters for @var{x} and @var{y} are expressions containing the
3810 following constants and functions:
3814 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3818 horizontal and vertical chroma subsample values. For example for the
3819 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3822 the height of each text line
3830 @item max_glyph_a, ascent
3831 the maximum distance from the baseline to the highest/upper grid
3832 coordinate used to place a glyph outline point, for all the rendered
3834 It is a positive value, due to the grid's orientation with the Y axis
3837 @item max_glyph_d, descent
3838 the maximum distance from the baseline to the lowest grid coordinate
3839 used to place a glyph outline point, for all the rendered glyphs.
3840 This is a negative value, due to the grid's orientation, with the Y axis
3844 maximum glyph height, that is the maximum height for all the glyphs
3845 contained in the rendered text, it is equivalent to @var{ascent} -
3849 maximum glyph width, that is the maximum width for all the glyphs
3850 contained in the rendered text
3853 the number of input frame, starting from 0
3855 @item rand(min, max)
3856 return a random number included between @var{min} and @var{max}
3859 The input sample aspect ratio.
3862 timestamp expressed in seconds, NAN if the input timestamp is unknown
3865 the height of the rendered text
3868 the width of the rendered text
3872 the x and y offset coordinates where the text is drawn.
3874 These parameters allow the @var{x} and @var{y} expressions to refer
3875 each other, so you can for example specify @code{y=x/dar}.
3878 @anchor{drawtext_expansion}
3879 @subsection Text expansion
3881 If @option{expansion} is set to @code{strftime},
3882 the filter recognizes strftime() sequences in the provided text and
3883 expands them accordingly. Check the documentation of strftime(). This
3884 feature is deprecated.
3886 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3888 If @option{expansion} is set to @code{normal} (which is the default),
3889 the following expansion mechanism is used.
3891 The backslash character '\', followed by any character, always expands to
3892 the second character.
3894 Sequence of the form @code{%@{...@}} are expanded. The text between the
3895 braces is a function name, possibly followed by arguments separated by ':'.
3896 If the arguments contain special characters or delimiters (':' or '@}'),
3897 they should be escaped.
3899 Note that they probably must also be escaped as the value for the
3900 @option{text} option in the filter argument string and as the filter
3901 argument in the filtergraph description, and possibly also for the shell,
3902 that makes up to four levels of escaping; using a text file avoids these
3905 The following functions are available:
3910 The expression evaluation result.
3912 It must take one argument specifying the expression to be evaluated,
3913 which accepts the same constants and functions as the @var{x} and
3914 @var{y} values. Note that not all constants should be used, for
3915 example the text size is not known when evaluating the expression, so
3916 the constants @var{text_w} and @var{text_h} will have an undefined
3919 @item expr_int_format, eif
3920 Evaluate the expression's value and output as formatted integer.
3922 First argument is expression to be evaluated, same as for @var{expr} function.
3923 Second argument specifies output format. Allowed values are 'x', 'X', 'd' and
3924 'u', they are treated exactly as in printf function.
3925 Third parameter is optional and sets the number of positions taken by output.
3926 Effectively this allows to add padding with zeros from the left.
3929 The time at which the filter is running, expressed in UTC.
3930 It can accept an argument: a strftime() format string.
3933 The time at which the filter is running, expressed in the local time zone.
3934 It can accept an argument: a strftime() format string.
3937 Frame metadata. It must take one argument specifying metadata key.
3940 The frame number, starting from 0.
3943 A 1 character description of the current picture type.
3946 The timestamp of the current frame.
3947 It can take up to two arguments.
3949 The first argument is the format of the timestamp; it defaults to @code{flt}
3950 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
3951 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
3953 The second argument is an offset added to the timestamp.
3957 @subsection Examples
3961 Draw "Test Text" with font FreeSerif, using the default values for the
3962 optional parameters.
3965 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
3969 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
3970 and y=50 (counting from the top-left corner of the screen), text is
3971 yellow with a red box around it. Both the text and the box have an
3975 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
3976 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
3979 Note that the double quotes are not necessary if spaces are not used
3980 within the parameter list.
3983 Show the text at the center of the video frame:
3985 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
3989 Show a text line sliding from right to left in the last row of the video
3990 frame. The file @file{LONG_LINE} is assumed to contain a single line
3993 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
3997 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
3999 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
4003 Draw a single green letter "g", at the center of the input video.
4004 The glyph baseline is placed at half screen height.
4006 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
4010 Show text for 1 second every 3 seconds:
4012 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
4016 Use fontconfig to set the font. Note that the colons need to be escaped.
4018 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
4022 Print the date of a real-time encoding (see strftime(3)):
4024 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
4028 Shwo text fading in and out (appearing/disappearing):
4031 DS=1.0 # display start
4032 DE=10.0 # display end
4033 FID=1.5 # fade in duration
4034 FOD=5 # fade out duration
4035 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 @}"
4040 For more information about libfreetype, check:
4041 @url{http://www.freetype.org/}.
4043 For more information about fontconfig, check:
4044 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
4046 For more information about libfribidi, check:
4047 @url{http://fribidi.org/}.
4051 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
4053 The filter accepts the following options:
4058 Set low and high threshold values used by the Canny thresholding
4061 The high threshold selects the "strong" edge pixels, which are then
4062 connected through 8-connectivity with the "weak" edge pixels selected
4063 by the low threshold.
4065 @var{low} and @var{high} threshold values must be chosen in the range
4066 [0,1], and @var{low} should be lesser or equal to @var{high}.
4068 Default value for @var{low} is @code{20/255}, and default value for @var{high}
4072 Define the drawing mode.
4076 Draw white/gray wires on black background.
4079 Mix the colors to create a paint/cartoon effect.
4082 Default value is @var{wires}.
4085 @subsection Examples
4089 Standard edge detection with custom values for the hysteresis thresholding:
4091 edgedetect=low=0.1:high=0.4
4095 Painting effect without thresholding:
4097 edgedetect=mode=colormix:high=0
4101 @section extractplanes
4103 Extract color channel components from input video stream into
4104 separate grayscale video streams.
4106 The filter accepts the following option:
4110 Set plane(s) to extract.
4112 Available values for planes are:
4123 Choosing planes not available in the input will result in an error.
4124 That means you cannot select @code{r}, @code{g}, @code{b} planes
4125 with @code{y}, @code{u}, @code{v} planes at same time.
4128 @subsection Examples
4132 Extract luma, u and v color channel component from input video frame
4133 into 3 grayscale outputs:
4135 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
4141 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4143 For each input image, the filter will compute the optimal mapping from
4144 the input to the output given the codebook length, that is the number
4145 of distinct output colors.
4147 This filter accepts the following options.
4150 @item codebook_length, l
4151 Set codebook length. The value must be a positive integer, and
4152 represents the number of distinct output colors. Default value is 256.
4155 Set the maximum number of iterations to apply for computing the optimal
4156 mapping. The higher the value the better the result and the higher the
4157 computation time. Default value is 1.
4160 Set a random seed, must be an integer included between 0 and
4161 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4162 will try to use a good random seed on a best effort basis.
4167 Apply a fade-in/out effect to the input video.
4169 It accepts the following parameters:
4173 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4175 Default is @code{in}.
4177 @item start_frame, s
4178 Specify the number of the frame to start applying the fade
4179 effect at. Default is 0.
4182 The number of frames that the fade effect lasts. At the end of the
4183 fade-in effect, the output video will have the same intensity as the input video.
4184 At the end of the fade-out transition, the output video will be filled with the
4185 selected @option{color}.
4189 If set to 1, fade only alpha channel, if one exists on the input.
4192 @item start_time, st
4193 Specify the timestamp (in seconds) of the frame to start to apply the fade
4194 effect. If both start_frame and start_time are specified, the fade will start at
4195 whichever comes last. Default is 0.
4198 The number of seconds for which the fade effect has to last. At the end of the
4199 fade-in effect the output video will have the same intensity as the input video,
4200 at the end of the fade-out transition the output video will be filled with the
4201 selected @option{color}.
4202 If both duration and nb_frames are specified, duration is used. Default is 0.
4205 Specify the color of the fade. Default is "black".
4208 @subsection Examples
4212 Fade in the first 30 frames of video:
4217 The command above is equivalent to:
4223 Fade out the last 45 frames of a 200-frame video:
4226 fade=type=out:start_frame=155:nb_frames=45
4230 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4232 fade=in:0:25, fade=out:975:25
4236 Make the first 5 frames yellow, then fade in from frame 5-24:
4238 fade=in:5:20:color=yellow
4242 Fade in alpha over first 25 frames of video:
4244 fade=in:0:25:alpha=1
4248 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4250 fade=t=in:st=5.5:d=0.5
4257 Extract a single field from an interlaced image using stride
4258 arithmetic to avoid wasting CPU time. The output frames are marked as
4261 The filter accepts the following options:
4265 Specify whether to extract the top (if the value is @code{0} or
4266 @code{top}) or the bottom field (if the value is @code{1} or
4272 Field matching filter for inverse telecine. It is meant to reconstruct the
4273 progressive frames from a telecined stream. The filter does not drop duplicated
4274 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4275 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4277 The separation of the field matching and the decimation is notably motivated by
4278 the possibility of inserting a de-interlacing filter fallback between the two.
4279 If the source has mixed telecined and real interlaced content,
4280 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4281 But these remaining combed frames will be marked as interlaced, and thus can be
4282 de-interlaced by a later filter such as @ref{yadif} before decimation.
4284 In addition to the various configuration options, @code{fieldmatch} can take an
4285 optional second stream, activated through the @option{ppsrc} option. If
4286 enabled, the frames reconstruction will be based on the fields and frames from
4287 this second stream. This allows the first input to be pre-processed in order to
4288 help the various algorithms of the filter, while keeping the output lossless
4289 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4290 or brightness/contrast adjustments can help.
4292 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4293 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4294 which @code{fieldmatch} is based on. While the semantic and usage are very
4295 close, some behaviour and options names can differ.
4297 The filter accepts the following options:
4301 Specify the assumed field order of the input stream. Available values are:
4305 Auto detect parity (use FFmpeg's internal parity value).
4307 Assume bottom field first.
4309 Assume top field first.
4312 Note that it is sometimes recommended not to trust the parity announced by the
4315 Default value is @var{auto}.
4318 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4319 sense that it won't risk creating jerkiness due to duplicate frames when
4320 possible, but if there are bad edits or blended fields it will end up
4321 outputting combed frames when a good match might actually exist. On the other
4322 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4323 but will almost always find a good frame if there is one. The other values are
4324 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4325 jerkiness and creating duplicate frames versus finding good matches in sections
4326 with bad edits, orphaned fields, blended fields, etc.
4328 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4330 Available values are:
4334 2-way matching (p/c)
4336 2-way matching, and trying 3rd match if still combed (p/c + n)
4338 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4340 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4341 still combed (p/c + n + u/b)
4343 3-way matching (p/c/n)
4345 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4346 detected as combed (p/c/n + u/b)
4349 The parenthesis at the end indicate the matches that would be used for that
4350 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4353 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4356 Default value is @var{pc_n}.
4359 Mark the main input stream as a pre-processed input, and enable the secondary
4360 input stream as the clean source to pick the fields from. See the filter
4361 introduction for more details. It is similar to the @option{clip2} feature from
4364 Default value is @code{0} (disabled).
4367 Set the field to match from. It is recommended to set this to the same value as
4368 @option{order} unless you experience matching failures with that setting. In
4369 certain circumstances changing the field that is used to match from can have a
4370 large impact on matching performance. Available values are:
4374 Automatic (same value as @option{order}).
4376 Match from the bottom field.
4378 Match from the top field.
4381 Default value is @var{auto}.
4384 Set whether or not chroma is included during the match comparisons. In most
4385 cases it is recommended to leave this enabled. You should set this to @code{0}
4386 only if your clip has bad chroma problems such as heavy rainbowing or other
4387 artifacts. Setting this to @code{0} could also be used to speed things up at
4388 the cost of some accuracy.
4390 Default value is @code{1}.
4394 These define an exclusion band which excludes the lines between @option{y0} and
4395 @option{y1} from being included in the field matching decision. An exclusion
4396 band can be used to ignore subtitles, a logo, or other things that may
4397 interfere with the matching. @option{y0} sets the starting scan line and
4398 @option{y1} sets the ending line; all lines in between @option{y0} and
4399 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4400 @option{y0} and @option{y1} to the same value will disable the feature.
4401 @option{y0} and @option{y1} defaults to @code{0}.
4404 Set the scene change detection threshold as a percentage of maximum change on
4405 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4406 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4407 @option{scthresh} is @code{[0.0, 100.0]}.
4409 Default value is @code{12.0}.
4412 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4413 account the combed scores of matches when deciding what match to use as the
4414 final match. Available values are:
4418 No final matching based on combed scores.
4420 Combed scores are only used when a scene change is detected.
4422 Use combed scores all the time.
4425 Default is @var{sc}.
4428 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4429 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4430 Available values are:
4434 No forced calculation.
4436 Force p/c/n calculations.
4438 Force p/c/n/u/b calculations.
4441 Default value is @var{none}.
4444 This is the area combing threshold used for combed frame detection. This
4445 essentially controls how "strong" or "visible" combing must be to be detected.
4446 Larger values mean combing must be more visible and smaller values mean combing
4447 can be less visible or strong and still be detected. Valid settings are from
4448 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4449 be detected as combed). This is basically a pixel difference value. A good
4450 range is @code{[8, 12]}.
4452 Default value is @code{9}.
4455 Sets whether or not chroma is considered in the combed frame decision. Only
4456 disable this if your source has chroma problems (rainbowing, etc.) that are
4457 causing problems for the combed frame detection with chroma enabled. Actually,
4458 using @option{chroma}=@var{0} is usually more reliable, except for the case
4459 where there is chroma only combing in the source.
4461 Default value is @code{0}.
4465 Respectively set the x-axis and y-axis size of the window used during combed
4466 frame detection. This has to do with the size of the area in which
4467 @option{combpel} pixels are required to be detected as combed for a frame to be
4468 declared combed. See the @option{combpel} parameter description for more info.
4469 Possible values are any number that is a power of 2 starting at 4 and going up
4472 Default value is @code{16}.
4475 The number of combed pixels inside any of the @option{blocky} by
4476 @option{blockx} size blocks on the frame for the frame to be detected as
4477 combed. While @option{cthresh} controls how "visible" the combing must be, this
4478 setting controls "how much" combing there must be in any localized area (a
4479 window defined by the @option{blockx} and @option{blocky} settings) on the
4480 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4481 which point no frames will ever be detected as combed). This setting is known
4482 as @option{MI} in TFM/VFM vocabulary.
4484 Default value is @code{80}.
4487 @anchor{p/c/n/u/b meaning}
4488 @subsection p/c/n/u/b meaning
4490 @subsubsection p/c/n
4492 We assume the following telecined stream:
4495 Top fields: 1 2 2 3 4
4496 Bottom fields: 1 2 3 4 4
4499 The numbers correspond to the progressive frame the fields relate to. Here, the
4500 first two frames are progressive, the 3rd and 4th are combed, and so on.
4502 When @code{fieldmatch} is configured to run a matching from bottom
4503 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4508 B 1 2 3 4 4 <-- matching reference
4517 As a result of the field matching, we can see that some frames get duplicated.
4518 To perform a complete inverse telecine, you need to rely on a decimation filter
4519 after this operation. See for instance the @ref{decimate} filter.
4521 The same operation now matching from top fields (@option{field}=@var{top})
4526 T 1 2 2 3 4 <-- matching reference
4536 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4537 basically, they refer to the frame and field of the opposite parity:
4540 @item @var{p} matches the field of the opposite parity in the previous frame
4541 @item @var{c} matches the field of the opposite parity in the current frame
4542 @item @var{n} matches the field of the opposite parity in the next frame
4547 The @var{u} and @var{b} matching are a bit special in the sense that they match
4548 from the opposite parity flag. In the following examples, we assume that we are
4549 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4550 'x' is placed above and below each matched fields.
4552 With bottom matching (@option{field}=@var{bottom}):
4557 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4558 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4566 With top matching (@option{field}=@var{top}):
4571 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4572 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4580 @subsection Examples
4582 Simple IVTC of a top field first telecined stream:
4584 fieldmatch=order=tff:combmatch=none, decimate
4587 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4589 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4594 Transform the field order of the input video.
4596 It accepts the following parameters:
4601 The output field order. Valid values are @var{tff} for top field first or @var{bff}
4602 for bottom field first.
4605 The default value is @samp{tff}.
4607 The transformation is done by shifting the picture content up or down
4608 by one line, and filling the remaining line with appropriate picture content.
4609 This method is consistent with most broadcast field order converters.
4611 If the input video is not flagged as being interlaced, or it is already
4612 flagged as being of the required output field order, then this filter does
4613 not alter the incoming video.
4615 It is very useful when converting to or from PAL DV material,
4616 which is bottom field first.
4620 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4625 Buffer input images and send them when they are requested.
4627 It is mainly useful when auto-inserted by the libavfilter
4630 It does not take parameters.
4635 Convert the input video to one of the specified pixel formats.
4636 Libavfilter will try to pick one that is suitable as input to
4639 It accepts the following parameters:
4643 A '|'-separated list of pixel format names, such as
4644 "pix_fmts=yuv420p|monow|rgb24".
4648 @subsection Examples
4652 Convert the input video to the @var{yuv420p} format
4654 format=pix_fmts=yuv420p
4657 Convert the input video to any of the formats in the list
4659 format=pix_fmts=yuv420p|yuv444p|yuv410p
4666 Convert the video to specified constant frame rate by duplicating or dropping
4667 frames as necessary.
4669 It accepts the following parameters:
4673 The desired output frame rate. The default is @code{25}.
4678 Possible values are:
4681 zero round towards 0
4685 round towards -infinity
4687 round towards +infinity
4691 The default is @code{near}.
4694 Assume the first PTS should be the given value, in seconds. This allows for
4695 padding/trimming at the start of stream. By default, no assumption is made
4696 about the first frame's expected PTS, so no padding or trimming is done.
4697 For example, this could be set to 0 to pad the beginning with duplicates of
4698 the first frame if a video stream starts after the audio stream or to trim any
4699 frames with a negative PTS.
4703 Alternatively, the options can be specified as a flat string:
4704 @var{fps}[:@var{round}].
4706 See also the @ref{setpts} filter.
4708 @subsection Examples
4712 A typical usage in order to set the fps to 25:
4718 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4720 fps=fps=film:round=near
4726 Pack two different video streams into a stereoscopic video, setting proper
4727 metadata on supported codecs. The two views should have the same size and
4728 framerate and processing will stop when the shorter video ends. Please note
4729 that you may conveniently adjust view properties with the @ref{scale} and
4732 It accepts the following parameters:
4736 The desired packing format. Supported values are:
4741 The views are next to each other (default).
4744 The views are on top of each other.
4747 The views are packed by line.
4750 The views are packed by column.
4753 The views are temporally interleaved.
4762 # Convert left and right views into a frame-sequential video
4763 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
4765 # Convert views into a side-by-side video with the same output resolution as the input
4766 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
4771 Select one frame every N-th frame.
4773 This filter accepts the following option:
4776 Select frame after every @code{step} frames.
4777 Allowed values are positive integers higher than 0. Default value is @code{1}.
4783 Apply a frei0r effect to the input video.
4785 To enable the compilation of this filter, you need to install the frei0r
4786 header and configure FFmpeg with @code{--enable-frei0r}.
4788 It accepts the following parameters:
4793 The name of the frei0r effect to load. If the environment variable
4794 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
4795 directories specified by the colon-separated list in @env{FREIOR_PATH}.
4796 Otherwise, the standard frei0r paths are searched, in this order:
4797 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
4798 @file{/usr/lib/frei0r-1/}.
4801 A '|'-separated list of parameters to pass to the frei0r effect.
4805 A frei0r effect parameter can be a boolean (its value is either
4806 "y" or "n"), a double, a color (specified as
4807 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
4808 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
4809 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
4810 @var{X} and @var{Y} are floating point numbers) and/or a string.
4812 The number and types of parameters depend on the loaded effect. If an
4813 effect parameter is not specified, the default value is set.
4815 @subsection Examples
4819 Apply the distort0r effect, setting the first two double parameters:
4821 frei0r=filter_name=distort0r:filter_params=0.5|0.01
4825 Apply the colordistance effect, taking a color as the first parameter:
4827 frei0r=colordistance:0.2/0.3/0.4
4828 frei0r=colordistance:violet
4829 frei0r=colordistance:0x112233
4833 Apply the perspective effect, specifying the top left and top right image
4836 frei0r=perspective:0.2/0.2|0.8/0.2
4840 For more information, see
4841 @url{http://frei0r.dyne.org}
4845 The filter accepts the following options:
4849 Set the luminance expression.
4851 Set the chrominance blue expression.
4853 Set the chrominance red expression.
4855 Set the alpha expression.
4857 Set the red expression.
4859 Set the green expression.
4861 Set the blue expression.
4864 The colorspace is selected according to the specified options. If one
4865 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4866 options is specified, the filter will automatically select a YCbCr
4867 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4868 @option{blue_expr} options is specified, it will select an RGB
4871 If one of the chrominance expression is not defined, it falls back on the other
4872 one. If no alpha expression is specified it will evaluate to opaque value.
4873 If none of chrominance expressions are specified, they will evaluate
4874 to the luminance expression.
4876 The expressions can use the following variables and functions:
4880 The sequential number of the filtered frame, starting from @code{0}.
4884 The coordinates of the current sample.
4888 The width and height of the image.
4892 Width and height scale depending on the currently filtered plane. It is the
4893 ratio between the corresponding luma plane number of pixels and the current
4894 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4895 @code{0.5,0.5} for chroma planes.
4898 Time of the current frame, expressed in seconds.
4901 Return the value of the pixel at location (@var{x},@var{y}) of the current
4905 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
4909 Return the value of the pixel at location (@var{x},@var{y}) of the
4910 blue-difference chroma plane. Return 0 if there is no such plane.
4913 Return the value of the pixel at location (@var{x},@var{y}) of the
4914 red-difference chroma plane. Return 0 if there is no such plane.
4919 Return the value of the pixel at location (@var{x},@var{y}) of the
4920 red/green/blue component. Return 0 if there is no such component.
4923 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
4924 plane. Return 0 if there is no such plane.
4927 For functions, if @var{x} and @var{y} are outside the area, the value will be
4928 automatically clipped to the closer edge.
4930 @subsection Examples
4934 Flip the image horizontally:
4940 Generate a bidimensional sine wave, with angle @code{PI/3} and a
4941 wavelength of 100 pixels:
4943 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
4947 Generate a fancy enigmatic moving light:
4949 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
4953 Generate a quick emboss effect:
4955 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
4959 Modify RGB components depending on pixel position:
4961 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
4967 Fix the banding artifacts that are sometimes introduced into nearly flat
4968 regions by truncation to 8bit color depth.
4969 Interpolate the gradients that should go where the bands are, and
4972 It is designed for playback only. Do not use it prior to
4973 lossy compression, because compression tends to lose the dither and
4974 bring back the bands.
4976 It accepts the following parameters:
4981 The maximum amount by which the filter will change any one pixel. This is also
4982 the threshold for detecting nearly flat regions. Acceptable values range from
4983 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
4987 The neighborhood to fit the gradient to. A larger radius makes for smoother
4988 gradients, but also prevents the filter from modifying the pixels near detailed
4989 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
4990 values will be clipped to the valid range.
4994 Alternatively, the options can be specified as a flat string:
4995 @var{strength}[:@var{radius}]
4997 @subsection Examples
5001 Apply the filter with a @code{3.5} strength and radius of @code{8}:
5007 Specify radius, omitting the strength (which will fall-back to the default
5018 Apply a Hald CLUT to a video stream.
5020 First input is the video stream to process, and second one is the Hald CLUT.
5021 The Hald CLUT input can be a simple picture or a complete video stream.
5023 The filter accepts the following options:
5027 Force termination when the shortest input terminates. Default is @code{0}.
5029 Continue applying the last CLUT after the end of the stream. A value of
5030 @code{0} disable the filter after the last frame of the CLUT is reached.
5031 Default is @code{1}.
5034 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
5035 filters share the same internals).
5037 More information about the Hald CLUT can be found on Eskil Steenberg's website
5038 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
5040 @subsection Workflow examples
5042 @subsubsection Hald CLUT video stream
5044 Generate an identity Hald CLUT stream altered with various effects:
5046 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
5049 Note: make sure you use a lossless codec.
5051 Then use it with @code{haldclut} to apply it on some random stream:
5053 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
5056 The Hald CLUT will be applied to the 10 first seconds (duration of
5057 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
5058 to the remaining frames of the @code{mandelbrot} stream.
5060 @subsubsection Hald CLUT with preview
5062 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
5063 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
5064 biggest possible square starting at the top left of the picture. The remaining
5065 padding pixels (bottom or right) will be ignored. This area can be used to add
5066 a preview of the Hald CLUT.
5068 Typically, the following generated Hald CLUT will be supported by the
5069 @code{haldclut} filter:
5072 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
5073 pad=iw+320 [padded_clut];
5074 smptebars=s=320x256, split [a][b];
5075 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
5076 [main][b] overlay=W-320" -frames:v 1 clut.png
5079 It contains the original and a preview of the effect of the CLUT: SMPTE color
5080 bars are displayed on the right-top, and below the same color bars processed by
5083 Then, the effect of this Hald CLUT can be visualized with:
5085 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
5090 Flip the input video horizontally.
5092 For example, to horizontally flip the input video with @command{ffmpeg}:
5094 ffmpeg -i in.avi -vf "hflip" out.avi
5098 This filter applies a global color histogram equalization on a
5101 It can be used to correct video that has a compressed range of pixel
5102 intensities. The filter redistributes the pixel intensities to
5103 equalize their distribution across the intensity range. It may be
5104 viewed as an "automatically adjusting contrast filter". This filter is
5105 useful only for correcting degraded or poorly captured source
5108 The filter accepts the following options:
5112 Determine the amount of equalization to be applied. As the strength
5113 is reduced, the distribution of pixel intensities more-and-more
5114 approaches that of the input frame. The value must be a float number
5115 in the range [0,1] and defaults to 0.200.
5118 Set the maximum intensity that can generated and scale the output
5119 values appropriately. The strength should be set as desired and then
5120 the intensity can be limited if needed to avoid washing-out. The value
5121 must be a float number in the range [0,1] and defaults to 0.210.
5124 Set the antibanding level. If enabled the filter will randomly vary
5125 the luminance of output pixels by a small amount to avoid banding of
5126 the histogram. Possible values are @code{none}, @code{weak} or
5127 @code{strong}. It defaults to @code{none}.
5132 Compute and draw a color distribution histogram for the input video.
5134 The computed histogram is a representation of the color component
5135 distribution in an image.
5137 The filter accepts the following options:
5143 It accepts the following values:
5146 Standard histogram that displays the color components distribution in an
5147 image. Displays color graph for each color component. Shows distribution of
5148 the Y, U, V, A or R, G, B components, depending on input format, in the
5149 current frame. Below each graph a color component scale meter is shown.
5152 Displays chroma values (U/V color placement) in a two dimensional
5153 graph (which is called a vectorscope). The brighter a pixel in the
5154 vectorscope, the more pixels of the input frame correspond to that pixel
5155 (i.e., more pixels have this chroma value). The V component is displayed on
5156 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5157 side being V = 255. The U component is displayed on the vertical (Y) axis,
5158 with the top representing U = 0 and the bottom representing U = 255.
5160 The position of a white pixel in the graph corresponds to the chroma value of
5161 a pixel of the input clip. The graph can therefore be used to read the hue
5162 (color flavor) and the saturation (the dominance of the hue in the color). As
5163 the hue of a color changes, it moves around the square. At the center of the
5164 square the saturation is zero, which means that the corresponding pixel has no
5165 color. If the amount of a specific color is increased (while leaving the other
5166 colors unchanged) the saturation increases, and the indicator moves towards
5167 the edge of the square.
5170 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5174 Per row/column color component graph. In row mode, the graph on the left side
5175 represents color component value 0 and the right side represents value = 255.
5176 In column mode, the top side represents color component value = 0 and bottom
5177 side represents value = 255.
5179 Default value is @code{levels}.
5182 Set height of level in @code{levels}. Default value is @code{200}.
5183 Allowed range is [50, 2048].
5186 Set height of color scale in @code{levels}. Default value is @code{12}.
5187 Allowed range is [0, 40].
5190 Set step for @code{waveform} mode. Smaller values are useful to find out how
5191 many values of the same luminance are distributed across input rows/columns.
5192 Default value is @code{10}. Allowed range is [1, 255].
5195 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5196 Default is @code{row}.
5198 @item waveform_mirror
5199 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5200 means mirrored. In mirrored mode, higher values will be represented on the left
5201 side for @code{row} mode and at the top for @code{column} mode. Default is
5202 @code{0} (unmirrored).
5205 Set display mode for @code{waveform} and @code{levels}.
5206 It accepts the following values:
5209 Display separate graph for the color components side by side in
5210 @code{row} waveform mode or one below the other in @code{column} waveform mode
5211 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5212 per color component graphs are placed below each other.
5214 Using this display mode in @code{waveform} histogram mode makes it easy to
5215 spot color casts in the highlights and shadows of an image, by comparing the
5216 contours of the top and the bottom graphs of each waveform. Since whites,
5217 grays, and blacks are characterized by exactly equal amounts of red, green,
5218 and blue, neutral areas of the picture should display three waveforms of
5219 roughly equal width/height. If not, the correction is easy to perform by
5220 making level adjustments the three waveforms.
5223 Presents information identical to that in the @code{parade}, except
5224 that the graphs representing color components are superimposed directly
5227 This display mode in @code{waveform} histogram mode makes it easier to spot
5228 relative differences or similarities in overlapping areas of the color
5229 components that are supposed to be identical, such as neutral whites, grays,
5232 Default is @code{parade}.
5235 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5236 Default is @code{linear}.
5239 @subsection Examples
5244 Calculate and draw histogram:
5246 ffplay -i input -vf histogram
5254 This is a high precision/quality 3d denoise filter. It aims to reduce
5255 image noise, producing smooth images and making still images really
5256 still. It should enhance compressibility.
5258 It accepts the following optional parameters:
5262 A non-negative floating point number which specifies spatial luma strength.
5265 @item chroma_spatial
5266 A non-negative floating point number which specifies spatial chroma strength.
5267 It defaults to 3.0*@var{luma_spatial}/4.0.
5270 A floating point number which specifies luma temporal strength. It defaults to
5271 6.0*@var{luma_spatial}/4.0.
5274 A floating point number which specifies chroma temporal strength. It defaults to
5275 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5280 Apply a high-quality magnification filter designed for pixel art. This filter
5281 was originally created by Maxim Stepin.
5283 It accepts the following option:
5287 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
5288 @code{hq3x} and @code{4} for @code{hq4x}.
5289 Default is @code{3}.
5294 Modify the hue and/or the saturation of the input.
5296 It accepts the following parameters:
5300 Specify the hue angle as a number of degrees. It accepts an expression,
5301 and defaults to "0".
5304 Specify the saturation in the [-10,10] range. It accepts an expression and
5308 Specify the hue angle as a number of radians. It accepts an
5309 expression, and defaults to "0".
5312 Specify the brightness in the [-10,10] range. It accepts an expression and
5316 @option{h} and @option{H} are mutually exclusive, and can't be
5317 specified at the same time.
5319 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5320 expressions containing the following constants:
5324 frame count of the input frame starting from 0
5327 presentation timestamp of the input frame expressed in time base units
5330 frame rate of the input video, NAN if the input frame rate is unknown
5333 timestamp expressed in seconds, NAN if the input timestamp is unknown
5336 time base of the input video
5339 @subsection Examples
5343 Set the hue to 90 degrees and the saturation to 1.0:
5349 Same command but expressing the hue in radians:
5355 Rotate hue and make the saturation swing between 0
5356 and 2 over a period of 1 second:
5358 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5362 Apply a 3 seconds saturation fade-in effect starting at 0:
5367 The general fade-in expression can be written as:
5369 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5373 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5375 hue="s=max(0\, min(1\, (8-t)/3))"
5378 The general fade-out expression can be written as:
5380 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5385 @subsection Commands
5387 This filter supports the following commands:
5393 Modify the hue and/or the saturation and/or brightness of the input video.
5394 The command accepts the same syntax of the corresponding option.
5396 If the specified expression is not valid, it is kept at its current
5402 Detect video interlacing type.
5404 This filter tries to detect if the input is interlaced or progressive,
5405 top or bottom field first.
5407 The filter accepts the following options:
5411 Set interlacing threshold.
5413 Set progressive threshold.
5418 Deinterleave or interleave fields.
5420 This filter allows one to process interlaced images fields without
5421 deinterlacing them. Deinterleaving splits the input frame into 2
5422 fields (so called half pictures). Odd lines are moved to the top
5423 half of the output image, even lines to the bottom half.
5424 You can process (filter) them independently and then re-interleave them.
5426 The filter accepts the following options:
5430 @item chroma_mode, c
5432 Available values for @var{luma_mode}, @var{chroma_mode} and
5433 @var{alpha_mode} are:
5439 @item deinterleave, d
5440 Deinterleave fields, placing one above the other.
5443 Interleave fields. Reverse the effect of deinterleaving.
5445 Default value is @code{none}.
5448 @item chroma_swap, cs
5449 @item alpha_swap, as
5450 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5455 Simple interlacing filter from progressive contents. This interleaves upper (or
5456 lower) lines from odd frames with lower (or upper) lines from even frames,
5457 halving the frame rate and preserving image height.
5460 Original Original New Frame
5461 Frame 'j' Frame 'j+1' (tff)
5462 ========== =========== ==================
5463 Line 0 --------------------> Frame 'j' Line 0
5464 Line 1 Line 1 ----> Frame 'j+1' Line 1
5465 Line 2 ---------------------> Frame 'j' Line 2
5466 Line 3 Line 3 ----> Frame 'j+1' Line 3
5468 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5471 It accepts the following optional parameters:
5475 This determines whether the interlaced frame is taken from the even
5476 (tff - default) or odd (bff) lines of the progressive frame.
5479 Enable (default) or disable the vertical lowpass filter to avoid twitter
5480 interlacing and reduce moire patterns.
5485 Deinterlace input video by applying Donald Graft's adaptive kernel
5486 deinterling. Work on interlaced parts of a video to produce
5489 The description of the accepted parameters follows.
5493 Set the threshold which affects the filter's tolerance when
5494 determining if a pixel line must be processed. It must be an integer
5495 in the range [0,255] and defaults to 10. A value of 0 will result in
5496 applying the process on every pixels.
5499 Paint pixels exceeding the threshold value to white if set to 1.
5503 Set the fields order. Swap fields if set to 1, leave fields alone if
5507 Enable additional sharpening if set to 1. Default is 0.
5510 Enable twoway sharpening if set to 1. Default is 0.
5513 @subsection Examples
5517 Apply default values:
5519 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5523 Enable additional sharpening:
5529 Paint processed pixels in white:
5538 Apply a 3D LUT to an input video.
5540 The filter accepts the following options:
5544 Set the 3D LUT file name.
5546 Currently supported formats:
5558 Select interpolation mode.
5560 Available values are:
5564 Use values from the nearest defined point.
5566 Interpolate values using the 8 points defining a cube.
5568 Interpolate values using a tetrahedron.
5572 @section lut, lutrgb, lutyuv
5574 Compute a look-up table for binding each pixel component input value
5575 to an output value, and apply it to the input video.
5577 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5578 to an RGB input video.
5580 These filters accept the following parameters:
5583 set first pixel component expression
5585 set second pixel component expression
5587 set third pixel component expression
5589 set fourth pixel component expression, corresponds to the alpha component
5592 set red component expression
5594 set green component expression
5596 set blue component expression
5598 alpha component expression
5601 set Y/luminance component expression
5603 set U/Cb component expression
5605 set V/Cr component expression
5608 Each of them specifies the expression to use for computing the lookup table for
5609 the corresponding pixel component values.
5611 The exact component associated to each of the @var{c*} options depends on the
5614 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5615 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5617 The expressions can contain the following constants and functions:
5622 The input width and height.
5625 The input value for the pixel component.
5628 The input value, clipped to the @var{minval}-@var{maxval} range.
5631 The maximum value for the pixel component.
5634 The minimum value for the pixel component.
5637 The negated value for the pixel component value, clipped to the
5638 @var{minval}-@var{maxval} range; it corresponds to the expression
5639 "maxval-clipval+minval".
5642 The computed value in @var{val}, clipped to the
5643 @var{minval}-@var{maxval} range.
5645 @item gammaval(gamma)
5646 The computed gamma correction value of the pixel component value,
5647 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
5649 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
5653 All expressions default to "val".
5655 @subsection Examples
5661 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
5662 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
5665 The above is the same as:
5667 lutrgb="r=negval:g=negval:b=negval"
5668 lutyuv="y=negval:u=negval:v=negval"
5678 Remove chroma components, turning the video into a graytone image:
5680 lutyuv="u=128:v=128"
5684 Apply a luma burning effect:
5690 Remove green and blue components:
5696 Set a constant alpha channel value on input:
5698 format=rgba,lutrgb=a="maxval-minval/2"
5702 Correct luminance gamma by a factor of 0.5:
5704 lutyuv=y=gammaval(0.5)
5708 Discard least significant bits of luma:
5710 lutyuv=y='bitand(val, 128+64+32)'
5714 @section mergeplanes
5716 Merge color channel components from several video streams.
5718 The filter accepts up to 4 input streams, and merge selected input
5719 planes to the output video.
5721 This filter accepts the following options:
5724 Set input to output plane mapping. Default is @code{0}.
5726 The mappings is specified as a bitmap. It should be specified as a
5727 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
5728 mapping for the first plane of the output stream. 'A' sets the number of
5729 the input stream to use (from 0 to 3), and 'a' the plane number of the
5730 corresponding input to use (from 0 to 3). The rest of the mappings is
5731 similar, 'Bb' describes the mapping for the output stream second
5732 plane, 'Cc' describes the mapping for the output stream third plane and
5733 'Dd' describes the mapping for the output stream fourth plane.
5736 Set output pixel format. Default is @code{yuva444p}.
5739 @subsection Examples
5743 Merge three gray video streams of same width and height into single video stream:
5745 [a0][a1][a2]mergeplanes=0x001020:yuv444p
5749 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
5751 [a0][a1]mergeplanes=0x00010210:yuva444p
5755 Swap Y and A plane in yuva444p stream:
5757 format=yuva444p,mergeplanes=0x03010200:yuva444p
5761 Swap U and V plane in yuv420p stream:
5763 format=yuv420p,mergeplanes=0x000201:yuv420p
5767 Cast a rgb24 clip to yuv444p:
5769 format=rgb24,mergeplanes=0x000102:yuv444p
5775 Apply motion-compensation deinterlacing.
5777 It needs one field per frame as input and must thus be used together
5778 with yadif=1/3 or equivalent.
5780 This filter accepts the following options:
5783 Set the deinterlacing mode.
5785 It accepts one of the following values:
5790 use iterative motion estimation
5792 like @samp{slow}, but use multiple reference frames.
5794 Default value is @samp{fast}.
5797 Set the picture field parity assumed for the input video. It must be
5798 one of the following values:
5802 assume top field first
5804 assume bottom field first
5807 Default value is @samp{bff}.
5810 Set per-block quantization parameter (QP) used by the internal
5813 Higher values should result in a smoother motion vector field but less
5814 optimal individual vectors. Default value is 1.
5819 Apply an MPlayer filter to the input video.
5821 This filter provides a wrapper around some of the filters of
5824 This wrapper is considered experimental. Some of the wrapped filters
5825 may not work properly and we may drop support for them, as they will
5826 be implemented natively into FFmpeg. Thus you should avoid
5827 depending on them when writing portable scripts.
5829 The filter accepts the parameters:
5830 @var{filter_name}[:=]@var{filter_params}
5832 @var{filter_name} is the name of a supported MPlayer filter,
5833 @var{filter_params} is a string containing the parameters accepted by
5836 The list of the currently supported filters follows:
5847 The parameter syntax and behavior for the listed filters are the same
5848 of the corresponding MPlayer filters. For detailed instructions check
5849 the "VIDEO FILTERS" section in the MPlayer manual.
5851 @subsection Examples
5855 Adjust gamma, brightness, contrast:
5861 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
5865 Drop frames that do not differ greatly from the previous frame in
5866 order to reduce frame rate.
5868 The main use of this filter is for very-low-bitrate encoding
5869 (e.g. streaming over dialup modem), but it could in theory be used for
5870 fixing movies that were inverse-telecined incorrectly.
5872 A description of the accepted options follows.
5876 Set the maximum number of consecutive frames which can be dropped (if
5877 positive), or the minimum interval between dropped frames (if
5878 negative). If the value is 0, the frame is dropped unregarding the
5879 number of previous sequentially dropped frames.
5886 Set the dropping threshold values.
5888 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
5889 represent actual pixel value differences, so a threshold of 64
5890 corresponds to 1 unit of difference for each pixel, or the same spread
5891 out differently over the block.
5893 A frame is a candidate for dropping if no 8x8 blocks differ by more
5894 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
5895 meaning the whole image) differ by more than a threshold of @option{lo}.
5897 Default value for @option{hi} is 64*12, default value for @option{lo} is
5898 64*5, and default value for @option{frac} is 0.33.
5906 It accepts an integer in input; if non-zero it negates the
5907 alpha component (if available). The default value in input is 0.
5911 Force libavfilter not to use any of the specified pixel formats for the
5912 input to the next filter.
5914 It accepts the following parameters:
5918 A '|'-separated list of pixel format names, such as
5919 apix_fmts=yuv420p|monow|rgb24".
5923 @subsection Examples
5927 Force libavfilter to use a format different from @var{yuv420p} for the
5928 input to the vflip filter:
5930 noformat=pix_fmts=yuv420p,vflip
5934 Convert the input video to any of the formats not contained in the list:
5936 noformat=yuv420p|yuv444p|yuv410p
5942 Add noise on video input frame.
5944 The filter accepts the following options:
5952 Set noise seed for specific pixel component or all pixel components in case
5953 of @var{all_seed}. Default value is @code{123457}.
5955 @item all_strength, alls
5956 @item c0_strength, c0s
5957 @item c1_strength, c1s
5958 @item c2_strength, c2s
5959 @item c3_strength, c3s
5960 Set noise strength for specific pixel component or all pixel components in case
5961 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
5963 @item all_flags, allf
5968 Set pixel component flags or set flags for all components if @var{all_flags}.
5969 Available values for component flags are:
5972 averaged temporal noise (smoother)
5974 mix random noise with a (semi)regular pattern
5976 temporal noise (noise pattern changes between frames)
5978 uniform noise (gaussian otherwise)
5982 @subsection Examples
5984 Add temporal and uniform noise to input video:
5986 noise=alls=20:allf=t+u
5991 Pass the video source unchanged to the output.
5995 Apply a video transform using libopencv.
5997 To enable this filter, install the libopencv library and headers and
5998 configure FFmpeg with @code{--enable-libopencv}.
6000 It accepts the following parameters:
6005 The name of the libopencv filter to apply.
6008 The parameters to pass to the libopencv filter. If not specified, the default
6013 Refer to the official libopencv documentation for more precise
6015 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
6017 Several libopencv filters are supported; see the following subsections.
6022 Dilate an image by using a specific structuring element.
6023 It corresponds to the libopencv function @code{cvDilate}.
6025 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
6027 @var{struct_el} represents a structuring element, and has the syntax:
6028 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
6030 @var{cols} and @var{rows} represent the number of columns and rows of
6031 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
6032 point, and @var{shape} the shape for the structuring element. @var{shape}
6033 must be "rect", "cross", "ellipse", or "custom".
6035 If the value for @var{shape} is "custom", it must be followed by a
6036 string of the form "=@var{filename}". The file with name
6037 @var{filename} is assumed to represent a binary image, with each
6038 printable character corresponding to a bright pixel. When a custom
6039 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
6040 or columns and rows of the read file are assumed instead.
6042 The default value for @var{struct_el} is "3x3+0x0/rect".
6044 @var{nb_iterations} specifies the number of times the transform is
6045 applied to the image, and defaults to 1.
6049 # Use the default values
6052 # Dilate using a structuring element with a 5x5 cross, iterating two times
6053 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
6055 # Read the shape from the file diamond.shape, iterating two times.
6056 # The file diamond.shape may contain a pattern of characters like this
6062 # The specified columns and rows are ignored
6063 # but the anchor point coordinates are not
6064 ocv=dilate:0x0+2x2/custom=diamond.shape|2
6069 Erode an image by using a specific structuring element.
6070 It corresponds to the libopencv function @code{cvErode}.
6072 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
6073 with the same syntax and semantics as the @ref{dilate} filter.
6077 Smooth the input video.
6079 The filter takes the following parameters:
6080 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
6082 @var{type} is the type of smooth filter to apply, and must be one of
6083 the following values: "blur", "blur_no_scale", "median", "gaussian",
6084 or "bilateral". The default value is "gaussian".
6086 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
6087 depend on the smooth type. @var{param1} and
6088 @var{param2} accept integer positive values or 0. @var{param3} and
6089 @var{param4} accept floating point values.
6091 The default value for @var{param1} is 3. The default value for the
6092 other parameters is 0.
6094 These parameters correspond to the parameters assigned to the
6095 libopencv function @code{cvSmooth}.
6100 Overlay one video on top of another.
6102 It takes two inputs and has one output. The first input is the "main"
6103 video on which the second input is overlayed.
6105 It accepts the following parameters:
6107 A description of the accepted options follows.
6112 Set the expression for the x and y coordinates of the overlayed video
6113 on the main video. Default value is "0" for both expressions. In case
6114 the expression is invalid, it is set to a huge value (meaning that the
6115 overlay will not be displayed within the output visible area).
6118 The action to take when EOF is encountered on the secondary input; it accepts
6119 one of the following values:
6123 Repeat the last frame (the default).
6127 Pass the main input through.
6131 Set when the expressions for @option{x}, and @option{y} are evaluated.
6133 It accepts the following values:
6136 only evaluate expressions once during the filter initialization or
6137 when a command is processed
6140 evaluate expressions for each incoming frame
6143 Default value is @samp{frame}.
6146 If set to 1, force the output to terminate when the shortest input
6147 terminates. Default value is 0.
6150 Set the format for the output video.
6152 It accepts the following values:
6167 Default value is @samp{yuv420}.
6169 @item rgb @emph{(deprecated)}
6170 If set to 1, force the filter to accept inputs in the RGB
6171 color space. Default value is 0. This option is deprecated, use
6172 @option{format} instead.
6175 If set to 1, force the filter to draw the last overlay frame over the
6176 main input until the end of the stream. A value of 0 disables this
6177 behavior. Default value is 1.
6180 The @option{x}, and @option{y} expressions can contain the following
6186 The main input width and height.
6190 The overlay input width and height.
6194 The computed values for @var{x} and @var{y}. They are evaluated for
6199 horizontal and vertical chroma subsample values of the output
6200 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6204 the number of input frame, starting from 0
6207 the position in the file of the input frame, NAN if unknown
6210 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6214 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6215 when evaluation is done @emph{per frame}, and will evaluate to NAN
6216 when @option{eval} is set to @samp{init}.
6218 Be aware that frames are taken from each input video in timestamp
6219 order, hence, if their initial timestamps differ, it is a good idea
6220 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6221 have them begin in the same zero timestamp, as the example for
6222 the @var{movie} filter does.
6224 You can chain together more overlays but you should test the
6225 efficiency of such approach.
6227 @subsection Commands
6229 This filter supports the following commands:
6233 Modify the x and y of the overlay input.
6234 The command accepts the same syntax of the corresponding option.
6236 If the specified expression is not valid, it is kept at its current
6240 @subsection Examples
6244 Draw the overlay at 10 pixels from the bottom right corner of the main
6247 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6250 Using named options the example above becomes:
6252 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6256 Insert a transparent PNG logo in the bottom left corner of the input,
6257 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6259 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6263 Insert 2 different transparent PNG logos (second logo on bottom
6264 right corner) using the @command{ffmpeg} tool:
6266 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
6270 Add a transparent color layer on top of the main video; @code{WxH}
6271 must specify the size of the main input to the overlay filter:
6273 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6277 Play an original video and a filtered version (here with the deshake
6278 filter) side by side using the @command{ffplay} tool:
6280 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6283 The above command is the same as:
6285 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6289 Make a sliding overlay appearing from the left to the right top part of the
6290 screen starting since time 2:
6292 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6296 Compose output by putting two input videos side to side:
6298 ffmpeg -i left.avi -i right.avi -filter_complex "
6299 nullsrc=size=200x100 [background];
6300 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6301 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6302 [background][left] overlay=shortest=1 [background+left];
6303 [background+left][right] overlay=shortest=1:x=100 [left+right]
6308 Mask 10-20 seconds of a video by applying the delogo filter to a section
6310 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6311 -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]'
6316 Chain several overlays in cascade:
6318 nullsrc=s=200x200 [bg];
6319 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6320 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6321 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6322 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6323 [in3] null, [mid2] overlay=100:100 [out0]
6330 Apply Overcomplete Wavelet denoiser.
6332 The filter accepts the following options:
6338 Larger depth values will denoise lower frequency components more, but
6339 slow down filtering.
6341 Must be an int in the range 8-16, default is @code{8}.
6343 @item luma_strength, ls
6346 Must be a double value in the range 0-1000, default is @code{1.0}.
6348 @item chroma_strength, cs
6349 Set chroma strength.
6351 Must be a double value in the range 0-1000, default is @code{1.0}.
6356 Add paddings to the input image, and place the original input at the
6357 provided @var{x}, @var{y} coordinates.
6359 It accepts the following parameters:
6364 Specify an expression for the size of the output image with the
6365 paddings added. If the value for @var{width} or @var{height} is 0, the
6366 corresponding input size is used for the output.
6368 The @var{width} expression can reference the value set by the
6369 @var{height} expression, and vice versa.
6371 The default value of @var{width} and @var{height} is 0.
6375 Specify the offsets to place the input image at within the padded area,
6376 with respect to the top/left border of the output image.
6378 The @var{x} expression can reference the value set by the @var{y}
6379 expression, and vice versa.
6381 The default value of @var{x} and @var{y} is 0.
6384 Specify the color of the padded area. For the syntax of this option,
6385 check the "Color" section in the ffmpeg-utils manual.
6387 The default value of @var{color} is "black".
6390 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6391 options are expressions containing the following constants:
6396 The input video width and height.
6400 These are the same as @var{in_w} and @var{in_h}.
6404 The output width and height (the size of the padded area), as
6405 specified by the @var{width} and @var{height} expressions.
6409 These are the same as @var{out_w} and @var{out_h}.
6413 The x and y offsets as specified by the @var{x} and @var{y}
6414 expressions, or NAN if not yet specified.
6417 same as @var{iw} / @var{ih}
6420 input sample aspect ratio
6423 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6427 The horizontal and vertical chroma subsample values. For example for the
6428 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6431 @subsection Examples
6435 Add paddings with the color "violet" to the input video. The output video
6436 size is 640x480, and the top-left corner of the input video is placed at
6439 pad=640:480:0:40:violet
6442 The example above is equivalent to the following command:
6444 pad=width=640:height=480:x=0:y=40:color=violet
6448 Pad the input to get an output with dimensions increased by 3/2,
6449 and put the input video at the center of the padded area:
6451 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6455 Pad the input to get a squared output with size equal to the maximum
6456 value between the input width and height, and put the input video at
6457 the center of the padded area:
6459 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6463 Pad the input to get a final w/h ratio of 16:9:
6465 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6469 In case of anamorphic video, in order to set the output display aspect
6470 correctly, it is necessary to use @var{sar} in the expression,
6471 according to the relation:
6473 (ih * X / ih) * sar = output_dar
6474 X = output_dar / sar
6477 Thus the previous example needs to be modified to:
6479 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6483 Double the output size and put the input video in the bottom-right
6484 corner of the output padded area:
6486 pad="2*iw:2*ih:ow-iw:oh-ih"
6490 @section perspective
6492 Correct perspective of video not recorded perpendicular to the screen.
6494 A description of the accepted parameters follows.
6505 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6506 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6508 The expressions can use the following variables:
6513 the width and height of video frame.
6517 Set interpolation for perspective correction.
6519 It accepts the following values:
6525 Default value is @samp{linear}.
6530 Delay interlaced video by one field time so that the field order changes.
6532 The intended use is to fix PAL movies that have been captured with the
6533 opposite field order to the film-to-video transfer.
6535 A description of the accepted parameters follows.
6541 It accepts the following values:
6544 Capture field order top-first, transfer bottom-first.
6545 Filter will delay the bottom field.
6548 Capture field order bottom-first, transfer top-first.
6549 Filter will delay the top field.
6552 Capture and transfer with the same field order. This mode only exists
6553 for the documentation of the other options to refer to, but if you
6554 actually select it, the filter will faithfully do nothing.
6557 Capture field order determined automatically by field flags, transfer
6559 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6560 basis using field flags. If no field information is available,
6561 then this works just like @samp{u}.
6564 Capture unknown or varying, transfer opposite.
6565 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6566 analyzing the images and selecting the alternative that produces best
6567 match between the fields.
6570 Capture top-first, transfer unknown or varying.
6571 Filter selects among @samp{t} and @samp{p} using image analysis.
6574 Capture bottom-first, transfer unknown or varying.
6575 Filter selects among @samp{b} and @samp{p} using image analysis.
6578 Capture determined by field flags, transfer unknown or varying.
6579 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6580 image analysis. If no field information is available, then this works just
6581 like @samp{U}. This is the default mode.
6584 Both capture and transfer unknown or varying.
6585 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
6589 @section pixdesctest
6591 Pixel format descriptor test filter, mainly useful for internal
6592 testing. The output video should be equal to the input video.
6596 format=monow, pixdesctest
6599 can be used to test the monowhite pixel format descriptor definition.
6603 Enable the specified chain of postprocessing subfilters using libpostproc. This
6604 library should be automatically selected with a GPL build (@code{--enable-gpl}).
6605 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
6606 Each subfilter and some options have a short and a long name that can be used
6607 interchangeably, i.e. dr/dering are the same.
6609 The filters accept the following options:
6613 Set postprocessing subfilters string.
6616 All subfilters share common options to determine their scope:
6620 Honor the quality commands for this subfilter.
6623 Do chrominance filtering, too (default).
6626 Do luminance filtering only (no chrominance).
6629 Do chrominance filtering only (no luminance).
6632 These options can be appended after the subfilter name, separated by a '|'.
6634 Available subfilters are:
6637 @item hb/hdeblock[|difference[|flatness]]
6638 Horizontal deblocking filter
6641 Difference factor where higher values mean more deblocking (default: @code{32}).
6643 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6646 @item vb/vdeblock[|difference[|flatness]]
6647 Vertical deblocking filter
6650 Difference factor where higher values mean more deblocking (default: @code{32}).
6652 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6655 @item ha/hadeblock[|difference[|flatness]]
6656 Accurate horizontal deblocking filter
6659 Difference factor where higher values mean more deblocking (default: @code{32}).
6661 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6664 @item va/vadeblock[|difference[|flatness]]
6665 Accurate vertical deblocking filter
6668 Difference factor where higher values mean more deblocking (default: @code{32}).
6670 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6674 The horizontal and vertical deblocking filters share the difference and
6675 flatness values so you cannot set different horizontal and vertical
6680 Experimental horizontal deblocking filter
6683 Experimental vertical deblocking filter
6688 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
6691 larger -> stronger filtering
6693 larger -> stronger filtering
6695 larger -> stronger filtering
6698 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
6701 Stretch luminance to @code{0-255}.
6704 @item lb/linblenddeint
6705 Linear blend deinterlacing filter that deinterlaces the given block by
6706 filtering all lines with a @code{(1 2 1)} filter.
6708 @item li/linipoldeint
6709 Linear interpolating deinterlacing filter that deinterlaces the given block by
6710 linearly interpolating every second line.
6712 @item ci/cubicipoldeint
6713 Cubic interpolating deinterlacing filter deinterlaces the given block by
6714 cubically interpolating every second line.
6716 @item md/mediandeint
6717 Median deinterlacing filter that deinterlaces the given block by applying a
6718 median filter to every second line.
6720 @item fd/ffmpegdeint
6721 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
6722 second line with a @code{(-1 4 2 4 -1)} filter.
6725 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
6726 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
6728 @item fq/forceQuant[|quantizer]
6729 Overrides the quantizer table from the input with the constant quantizer you
6737 Default pp filter combination (@code{hb|a,vb|a,dr|a})
6740 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
6743 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
6746 @subsection Examples
6750 Apply horizontal and vertical deblocking, deringing and automatic
6751 brightness/contrast:
6757 Apply default filters without brightness/contrast correction:
6763 Apply default filters and temporal denoiser:
6765 pp=default/tmpnoise|1|2|3
6769 Apply deblocking on luminance only, and switch vertical deblocking on or off
6770 automatically depending on available CPU time:
6778 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
6779 Ratio) between two input videos.
6781 This filter takes in input two input videos, the first input is
6782 considered the "main" source and is passed unchanged to the
6783 output. The second input is used as a "reference" video for computing
6786 Both video inputs must have the same resolution and pixel format for
6787 this filter to work correctly. Also it assumes that both inputs
6788 have the same number of frames, which are compared one by one.
6790 The obtained average PSNR is printed through the logging system.
6792 The filter stores the accumulated MSE (mean squared error) of each
6793 frame, and at the end of the processing it is averaged across all frames
6794 equally, and the following formula is applied to obtain the PSNR:
6797 PSNR = 10*log10(MAX^2/MSE)
6800 Where MAX is the average of the maximum values of each component of the
6803 The description of the accepted parameters follows.
6807 If specified the filter will use the named file to save the PSNR of
6808 each individual frame.
6811 The file printed if @var{stats_file} is selected, contains a sequence of
6812 key/value pairs of the form @var{key}:@var{value} for each compared
6815 A description of each shown parameter follows:
6819 sequential number of the input frame, starting from 1
6822 Mean Square Error pixel-by-pixel average difference of the compared
6823 frames, averaged over all the image components.
6825 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
6826 Mean Square Error pixel-by-pixel average difference of the compared
6827 frames for the component specified by the suffix.
6829 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
6830 Peak Signal to Noise ratio of the compared frames for the component
6831 specified by the suffix.
6836 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
6837 [main][ref] psnr="stats_file=stats.log" [out]
6840 On this example the input file being processed is compared with the
6841 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
6842 is stored in @file{stats.log}.
6847 Pulldown reversal (inverse telecine) filter, capable of handling mixed
6848 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
6851 The pullup filter is designed to take advantage of future context in making
6852 its decisions. This filter is stateless in the sense that it does not lock
6853 onto a pattern to follow, but it instead looks forward to the following
6854 fields in order to identify matches and rebuild progressive frames.
6856 To produce content with an even framerate, insert the fps filter after
6857 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
6858 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
6860 The filter accepts the following options:
6867 These options set the amount of "junk" to ignore at the left, right, top, and
6868 bottom of the image, respectively. Left and right are in units of 8 pixels,
6869 while top and bottom are in units of 2 lines.
6870 The default is 8 pixels on each side.
6873 Set the strict breaks. Setting this option to 1 will reduce the chances of
6874 filter generating an occasional mismatched frame, but it may also cause an
6875 excessive number of frames to be dropped during high motion sequences.
6876 Conversely, setting it to -1 will make filter match fields more easily.
6877 This may help processing of video where there is slight blurring between
6878 the fields, but may also cause there to be interlaced frames in the output.
6879 Default value is @code{0}.
6882 Set the metric plane to use. It accepts the following values:
6888 Use chroma blue plane.
6891 Use chroma red plane.
6894 This option may be set to use chroma plane instead of the default luma plane
6895 for doing filter's computations. This may improve accuracy on very clean
6896 source material, but more likely will decrease accuracy, especially if there
6897 is chroma noise (rainbow effect) or any grayscale video.
6898 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
6899 load and make pullup usable in realtime on slow machines.
6902 For best results (without duplicated frames in the output file) it is
6903 necessary to change the output frame rate. For example, to inverse
6904 telecine NTSC input:
6906 ffmpeg -i input -vf pullup -r 24000/1001 ...
6911 Suppress a TV station logo, using an image file to determine which
6912 pixels comprise the logo. It works by filling in the pixels that
6913 comprise the logo with neighboring pixels.
6915 The filter accepts the following options:
6919 Set the filter bitmap file, which can be any image format supported by
6920 libavformat. The width and height of the image file must match those of the
6921 video stream being processed.
6924 Pixels in the provided bitmap image with a value of zero are not
6925 considered part of the logo, non-zero pixels are considered part of
6926 the logo. If you use white (255) for the logo and black (0) for the
6927 rest, you will be safe. For making the filter bitmap, it is
6928 recommended to take a screen capture of a black frame with the logo
6929 visible, and then using a threshold filter followed by the erode
6930 filter once or twice.
6932 If needed, little splotches can be fixed manually. Remember that if
6933 logo pixels are not covered, the filter quality will be much
6934 reduced. Marking too many pixels as part of the logo does not hurt as
6935 much, but it will increase the amount of blurring needed to cover over
6936 the image and will destroy more information than necessary, and extra
6937 pixels will slow things down on a large logo.
6941 Rotate video by an arbitrary angle expressed in radians.
6943 The filter accepts the following options:
6945 A description of the optional parameters follows.
6948 Set an expression for the angle by which to rotate the input video
6949 clockwise, expressed as a number of radians. A negative value will
6950 result in a counter-clockwise rotation. By default it is set to "0".
6952 This expression is evaluated for each frame.
6955 Set the output width expression, default value is "iw".
6956 This expression is evaluated just once during configuration.
6959 Set the output height expression, default value is "ih".
6960 This expression is evaluated just once during configuration.
6963 Enable bilinear interpolation if set to 1, a value of 0 disables
6964 it. Default value is 1.
6967 Set the color used to fill the output area not covered by the rotated
6968 image. For the generalsyntax of this option, check the "Color" section in the
6969 ffmpeg-utils manual. If the special value "none" is selected then no
6970 background is printed (useful for example if the background is never shown).
6972 Default value is "black".
6975 The expressions for the angle and the output size can contain the
6976 following constants and functions:
6980 sequential number of the input frame, starting from 0. It is always NAN
6981 before the first frame is filtered.
6984 time in seconds of the input frame, it is set to 0 when the filter is
6985 configured. It is always NAN before the first frame is filtered.
6989 horizontal and vertical chroma subsample values. For example for the
6990 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6994 the input video width and height
6998 the output width and height, that is the size of the padded area as
6999 specified by the @var{width} and @var{height} expressions
7003 the minimal width/height required for completely containing the input
7004 video rotated by @var{a} radians.
7006 These are only available when computing the @option{out_w} and
7007 @option{out_h} expressions.
7010 @subsection Examples
7014 Rotate the input by PI/6 radians clockwise:
7020 Rotate the input by PI/6 radians counter-clockwise:
7026 Rotate the input by 45 degrees clockwise:
7032 Apply a constant rotation with period T, starting from an angle of PI/3:
7034 rotate=PI/3+2*PI*t/T
7038 Make the input video rotation oscillating with a period of T
7039 seconds and an amplitude of A radians:
7041 rotate=A*sin(2*PI/T*t)
7045 Rotate the video, output size is chosen so that the whole rotating
7046 input video is always completely contained in the output:
7048 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
7052 Rotate the video, reduce the output size so that no background is ever
7055 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
7059 @subsection Commands
7061 The filter supports the following commands:
7065 Set the angle expression.
7066 The command accepts the same syntax of the corresponding option.
7068 If the specified expression is not valid, it is kept at its current
7074 Apply Shape Adaptive Blur.
7076 The filter accepts the following options:
7079 @item luma_radius, lr
7080 Set luma blur filter strength, must be a value in range 0.1-4.0, default
7081 value is 1.0. A greater value will result in a more blurred image, and
7082 in slower processing.
7084 @item luma_pre_filter_radius, lpfr
7085 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
7088 @item luma_strength, ls
7089 Set luma maximum difference between pixels to still be considered, must
7090 be a value in the 0.1-100.0 range, default value is 1.0.
7092 @item chroma_radius, cr
7093 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
7094 greater value will result in a more blurred image, and in slower
7097 @item chroma_pre_filter_radius, cpfr
7098 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
7100 @item chroma_strength, cs
7101 Set chroma maximum difference between pixels to still be considered,
7102 must be a value in the 0.1-100.0 range.
7105 Each chroma option value, if not explicitly specified, is set to the
7106 corresponding luma option value.
7111 Scale (resize) the input video, using the libswscale library.
7113 The scale filter forces the output display aspect ratio to be the same
7114 of the input, by changing the output sample aspect ratio.
7116 If the input image format is different from the format requested by
7117 the next filter, the scale filter will convert the input to the
7121 The filter accepts the following options, or any of the options
7122 supported by the libswscale scaler.
7124 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
7125 the complete list of scaler options.
7130 Set the output video dimension expression. Default value is the input
7133 If the value is 0, the input width is used for the output.
7135 If one of the values is -1, the scale filter will use a value that
7136 maintains the aspect ratio of the input image, calculated from the
7137 other specified dimension. If both of them are -1, the input size is
7140 If one of the values is -n with n > 1, the scale filter will also use a value
7141 that maintains the aspect ratio of the input image, calculated from the other
7142 specified dimension. After that it will, however, make sure that the calculated
7143 dimension is divisible by n and adjust the value if necessary.
7145 See below for the list of accepted constants for use in the dimension
7149 Set the interlacing mode. It accepts the following values:
7153 Force interlaced aware scaling.
7156 Do not apply interlaced scaling.
7159 Select interlaced aware scaling depending on whether the source frames
7160 are flagged as interlaced or not.
7163 Default value is @samp{0}.
7166 Set libswscale scaling flags. See
7167 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7168 complete list of values. If not explicitly specified the filter applies
7172 Set the video size. For the syntax of this option, check the "Video size"
7173 section in the ffmpeg-utils manual.
7175 @item in_color_matrix
7176 @item out_color_matrix
7177 Set in/output YCbCr color space type.
7179 This allows the autodetected value to be overridden as well as allows forcing
7180 a specific value used for the output and encoder.
7182 If not specified, the color space type depends on the pixel format.
7188 Choose automatically.
7191 Format conforming to International Telecommunication Union (ITU)
7192 Recommendation BT.709.
7195 Set color space conforming to the United States Federal Communications
7196 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7199 Set color space conforming to:
7203 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7206 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7209 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7214 Set color space conforming to SMPTE ST 240:1999.
7219 Set in/output YCbCr sample range.
7221 This allows the autodetected value to be overridden as well as allows forcing
7222 a specific value used for the output and encoder. If not specified, the
7223 range depends on the pixel format. Possible values:
7227 Choose automatically.
7230 Set full range (0-255 in case of 8-bit luma).
7233 Set "MPEG" range (16-235 in case of 8-bit luma).
7236 @item force_original_aspect_ratio
7237 Enable decreasing or increasing output video width or height if necessary to
7238 keep the original aspect ratio. Possible values:
7242 Scale the video as specified and disable this feature.
7245 The output video dimensions will automatically be decreased if needed.
7248 The output video dimensions will automatically be increased if needed.
7252 One useful instance of this option is that when you know a specific device's
7253 maximum allowed resolution, you can use this to limit the output video to
7254 that, while retaining the aspect ratio. For example, device A allows
7255 1280x720 playback, and your video is 1920x800. Using this option (set it to
7256 decrease) and specifying 1280x720 to the command line makes the output
7259 Please note that this is a different thing than specifying -1 for @option{w}
7260 or @option{h}, you still need to specify the output resolution for this option
7265 The values of the @option{w} and @option{h} options are expressions
7266 containing the following constants:
7271 The input width and height
7275 These are the same as @var{in_w} and @var{in_h}.
7279 The output (scaled) width and height
7283 These are the same as @var{out_w} and @var{out_h}
7286 The same as @var{iw} / @var{ih}
7289 input sample aspect ratio
7292 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7296 horizontal and vertical input chroma subsample values. For example for the
7297 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7301 horizontal and vertical output chroma subsample values. For example for the
7302 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7305 @subsection Examples
7309 Scale the input video to a size of 200x100
7314 This is equivalent to:
7325 Specify a size abbreviation for the output size:
7330 which can also be written as:
7336 Scale the input to 2x:
7342 The above is the same as:
7348 Scale the input to 2x with forced interlaced scaling:
7350 scale=2*iw:2*ih:interl=1
7354 Scale the input to half size:
7360 Increase the width, and set the height to the same size:
7373 Increase the height, and set the width to 3/2 of the height:
7375 scale=w=3/2*oh:h=3/5*ih
7379 Increase the size, making the size a multiple of the chroma
7382 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7386 Increase the width to a maximum of 500 pixels,
7387 keeping the same aspect ratio as the input:
7389 scale=w='min(500\, iw*3/2):h=-1'
7393 @section separatefields
7395 The @code{separatefields} takes a frame-based video input and splits
7396 each frame into its components fields, producing a new half height clip
7397 with twice the frame rate and twice the frame count.
7399 This filter use field-dominance information in frame to decide which
7400 of each pair of fields to place first in the output.
7401 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7403 @section setdar, setsar
7405 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7408 This is done by changing the specified Sample (aka Pixel) Aspect
7409 Ratio, according to the following equation:
7411 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7414 Keep in mind that the @code{setdar} filter does not modify the pixel
7415 dimensions of the video frame. Also, the display aspect ratio set by
7416 this filter may be changed by later filters in the filterchain,
7417 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7420 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7421 the filter output video.
7423 Note that as a consequence of the application of this filter, the
7424 output display aspect ratio will change according to the equation
7427 Keep in mind that the sample aspect ratio set by the @code{setsar}
7428 filter may be changed by later filters in the filterchain, e.g. if
7429 another "setsar" or a "setdar" filter is applied.
7431 It accepts the following parameters:
7434 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7435 Set the aspect ratio used by the filter.
7437 The parameter can be a floating point number string, an expression, or
7438 a string of the form @var{num}:@var{den}, where @var{num} and
7439 @var{den} are the numerator and denominator of the aspect ratio. If
7440 the parameter is not specified, it is assumed the value "0".
7441 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7445 Set the maximum integer value to use for expressing numerator and
7446 denominator when reducing the expressed aspect ratio to a rational.
7447 Default value is @code{100}.
7451 The parameter @var{sar} is an expression containing
7452 the following constants:
7456 These are approximated values for the mathematical constants e
7457 (Euler's number), pi (Greek pi), and phi (the golden ratio).
7460 The input width and height.
7463 These are the same as @var{w} / @var{h}.
7466 The input sample aspect ratio.
7469 The input display aspect ratio. It is the same as
7470 (@var{w} / @var{h}) * @var{sar}.
7473 Horizontal and vertical chroma subsample values. For example, for the
7474 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7477 @subsection Examples
7482 To change the display aspect ratio to 16:9, specify one of the following:
7490 To change the sample aspect ratio to 10:11, specify:
7496 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7497 1000 in the aspect ratio reduction, use the command:
7499 setdar=ratio=16/9:max=1000
7507 Force field for the output video frame.
7509 The @code{setfield} filter marks the interlace type field for the
7510 output frames. It does not change the input frame, but only sets the
7511 corresponding property, which affects how the frame is treated by
7512 following filters (e.g. @code{fieldorder} or @code{yadif}).
7514 The filter accepts the following options:
7519 Available values are:
7523 Keep the same field property.
7526 Mark the frame as bottom-field-first.
7529 Mark the frame as top-field-first.
7532 Mark the frame as progressive.
7538 Show a line containing various information for each input video frame.
7539 The input video is not modified.
7541 The shown line contains a sequence of key/value pairs of the form
7542 @var{key}:@var{value}.
7544 It accepts the following parameters:
7548 The (sequential) number of the input frame, starting from 0.
7551 The Presentation TimeStamp of the input frame, expressed as a number of
7552 time base units. The time base unit depends on the filter input pad.
7555 The Presentation TimeStamp of the input frame, expressed as a number of
7559 The position of the frame in the input stream, or -1 if this information is
7560 unavailable and/or meaningless (for example in case of synthetic video).
7563 The pixel format name.
7566 The sample aspect ratio of the input frame, expressed in the form
7567 @var{num}/@var{den}.
7570 The size of the input frame. For the syntax of this option, check the "Video size"
7571 section in the ffmpeg-utils manual.
7574 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
7575 for bottom field first).
7578 This is 1 if the frame is a key frame, 0 otherwise.
7581 The picture type of the input frame ("I" for an I-frame, "P" for a
7582 P-frame, "B" for a B-frame, or "?" for an unknown type).
7583 Also refer to the documentation of the @code{AVPictureType} enum and of
7584 the @code{av_get_picture_type_char} function defined in
7585 @file{libavutil/avutil.h}.
7588 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
7590 @item plane_checksum
7591 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
7592 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
7595 @section shuffleplanes
7597 Reorder and/or duplicate video planes.
7599 It accepts the following parameters:
7604 The index of the input plane to be used as the first output plane.
7607 The index of the input plane to be used as the second output plane.
7610 The index of the input plane to be used as the third output plane.
7613 The index of the input plane to be used as the fourth output plane.
7617 The first plane has the index 0. The default is to keep the input unchanged.
7619 Swap the second and third planes of the input:
7621 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
7624 @section signalstats
7625 Evaluate various visual metrics that assist in determining issues associated
7626 with the digitization of analog video media.
7628 By default the filter will log these metadata values:
7632 Display the minimal Y value contained within the input frame. Expressed in
7636 Display the Y value at the 10% percentile within the input frame. Expressed in
7640 Display the average Y value within the input frame. Expressed in range of
7644 Display the Y value at the 90% percentile within the input frame. Expressed in
7648 Display the maximum Y value contained within the input frame. Expressed in
7652 Display the minimal U value contained within the input frame. Expressed in
7656 Display the U value at the 10% percentile within the input frame. Expressed in
7660 Display the average U value within the input frame. Expressed in range of
7664 Display the U value at the 90% percentile within the input frame. Expressed in
7668 Display the maximum U value contained within the input frame. Expressed in
7672 Display the minimal V value contained within the input frame. Expressed in
7676 Display the V value at the 10% percentile within the input frame. Expressed in
7680 Display the average V value within the input frame. Expressed in range of
7684 Display the V value at the 90% percentile within the input frame. Expressed in
7688 Display the maximum V value contained within the input frame. Expressed in
7692 Display the minimal saturation value contained within the input frame.
7693 Expressed in range of [0-~181.02].
7696 Display the saturation value at the 10% percentile within the input frame.
7697 Expressed in range of [0-~181.02].
7700 Display the average saturation value within the input frame. Expressed in range
7704 Display the saturation value at the 90% percentile within the input frame.
7705 Expressed in range of [0-~181.02].
7708 Display the maximum saturation value contained within the input frame.
7709 Expressed in range of [0-~181.02].
7712 Display the median value for hue within the input frame. Expressed in range of
7716 Display the average value for hue within the input frame. Expressed in range of
7720 Display the average of sample value difference between all values of the Y
7721 plane in the current frame and corresponding values of the previous input frame.
7722 Expressed in range of [0-255].
7725 Display the average of sample value difference between all values of the U
7726 plane in the current frame and corresponding values of the previous input frame.
7727 Expressed in range of [0-255].
7730 Display the average of sample value difference between all values of the V
7731 plane in the current frame and corresponding values of the previous input frame.
7732 Expressed in range of [0-255].
7735 The filter accepts the following options:
7741 @option{stat} specify an additional form of image analysis.
7742 @option{out} output video with the specified type of pixel highlighted.
7744 Both options accept the following values:
7748 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
7749 unlike the neighboring pixels of the same field. Examples of temporal outliers
7750 include the results of video dropouts, head clogs, or tape tracking issues.
7753 Identify @var{vertical line repetition}. Vertical line repetition includes
7754 similar rows of pixels within a frame. In born-digital video vertical line
7755 repetition is common, but this pattern is uncommon in video digitized from an
7756 analog source. When it occurs in video that results from the digitization of an
7757 analog source it can indicate concealment from a dropout compensator.
7760 Identify pixels that fall outside of legal broadcast range.
7764 Set the highlight color for the @option{out} option. The default color is
7768 @subsection Examples
7772 Output data of various video metrics:
7774 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
7778 Output specific data about the minimum and maximum values of the Y plane per frame:
7780 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
7784 Playback video while highlighting pixels that are outside of broadcast range in red.
7786 ffplay example.mov -vf signalstats="out=brng:color=red"
7790 Playback video with signalstats metadata drawn over the frame.
7792 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
7795 The contents of signalstat_drawtext.txt used in the command are:
7798 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
7799 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
7800 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
7801 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
7809 Blur the input video without impacting the outlines.
7811 It accepts the following options:
7814 @item luma_radius, lr
7815 Set the luma radius. The option value must be a float number in
7816 the range [0.1,5.0] that specifies the variance of the gaussian filter
7817 used to blur the image (slower if larger). Default value is 1.0.
7819 @item luma_strength, ls
7820 Set the luma strength. The option value must be a float number
7821 in the range [-1.0,1.0] that configures the blurring. A value included
7822 in [0.0,1.0] will blur the image whereas a value included in
7823 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7825 @item luma_threshold, lt
7826 Set the luma threshold used as a coefficient to determine
7827 whether a pixel should be blurred or not. The option value must be an
7828 integer in the range [-30,30]. A value of 0 will filter all the image,
7829 a value included in [0,30] will filter flat areas and a value included
7830 in [-30,0] will filter edges. Default value is 0.
7832 @item chroma_radius, cr
7833 Set the chroma radius. The option value must be a float number in
7834 the range [0.1,5.0] that specifies the variance of the gaussian filter
7835 used to blur the image (slower if larger). Default value is 1.0.
7837 @item chroma_strength, cs
7838 Set the chroma strength. The option value must be a float number
7839 in the range [-1.0,1.0] that configures the blurring. A value included
7840 in [0.0,1.0] will blur the image whereas a value included in
7841 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7843 @item chroma_threshold, ct
7844 Set the chroma threshold used as a coefficient to determine
7845 whether a pixel should be blurred or not. The option value must be an
7846 integer in the range [-30,30]. A value of 0 will filter all the image,
7847 a value included in [0,30] will filter flat areas and a value included
7848 in [-30,0] will filter edges. Default value is 0.
7851 If a chroma option is not explicitly set, the corresponding luma value
7856 Convert between different stereoscopic image formats.
7858 The filters accept the following options:
7862 Set stereoscopic image format of input.
7864 Available values for input image formats are:
7867 side by side parallel (left eye left, right eye right)
7870 side by side crosseye (right eye left, left eye right)
7873 side by side parallel with half width resolution
7874 (left eye left, right eye right)
7877 side by side crosseye with half width resolution
7878 (right eye left, left eye right)
7881 above-below (left eye above, right eye below)
7884 above-below (right eye above, left eye below)
7887 above-below with half height resolution
7888 (left eye above, right eye below)
7891 above-below with half height resolution
7892 (right eye above, left eye below)
7895 alternating frames (left eye first, right eye second)
7898 alternating frames (right eye first, left eye second)
7900 Default value is @samp{sbsl}.
7904 Set stereoscopic image format of output.
7906 Available values for output image formats are all the input formats as well as:
7909 anaglyph red/blue gray
7910 (red filter on left eye, blue filter on right eye)
7913 anaglyph red/green gray
7914 (red filter on left eye, green filter on right eye)
7917 anaglyph red/cyan gray
7918 (red filter on left eye, cyan filter on right eye)
7921 anaglyph red/cyan half colored
7922 (red filter on left eye, cyan filter on right eye)
7925 anaglyph red/cyan color
7926 (red filter on left eye, cyan filter on right eye)
7929 anaglyph red/cyan color optimized with the least squares projection of dubois
7930 (red filter on left eye, cyan filter on right eye)
7933 anaglyph green/magenta gray
7934 (green filter on left eye, magenta filter on right eye)
7937 anaglyph green/magenta half colored
7938 (green filter on left eye, magenta filter on right eye)
7941 anaglyph green/magenta colored
7942 (green filter on left eye, magenta filter on right eye)
7945 anaglyph green/magenta color optimized with the least squares projection of dubois
7946 (green filter on left eye, magenta filter on right eye)
7949 anaglyph yellow/blue gray
7950 (yellow filter on left eye, blue filter on right eye)
7953 anaglyph yellow/blue half colored
7954 (yellow filter on left eye, blue filter on right eye)
7957 anaglyph yellow/blue colored
7958 (yellow filter on left eye, blue filter on right eye)
7961 anaglyph yellow/blue color optimized with the least squares projection of dubois
7962 (yellow filter on left eye, blue filter on right eye)
7965 interleaved rows (left eye has top row, right eye starts on next row)
7968 interleaved rows (right eye has top row, left eye starts on next row)
7971 mono output (left eye only)
7974 mono output (right eye only)
7977 Default value is @samp{arcd}.
7980 @subsection Examples
7984 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
7990 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
7998 Apply a simple postprocessing filter that compresses and decompresses the image
7999 at several (or - in the case of @option{quality} level @code{6} - all) shifts
8000 and average the results.
8002 The filter accepts the following options:
8006 Set quality. This option defines the number of levels for averaging. It accepts
8007 an integer in the range 0-6. If set to @code{0}, the filter will have no
8008 effect. A value of @code{6} means the higher quality. For each increment of
8009 that value the speed drops by a factor of approximately 2. Default value is
8013 Force a constant quantization parameter. If not set, the filter will use the QP
8014 from the video stream (if available).
8017 Set thresholding mode. Available modes are:
8021 Set hard thresholding (default).
8023 Set soft thresholding (better de-ringing effect, but likely blurrier).
8027 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8028 option may cause flicker since the B-Frames have often larger QP. Default is
8029 @code{0} (not enabled).
8035 Draw subtitles on top of input video using the libass library.
8037 To enable compilation of this filter you need to configure FFmpeg with
8038 @code{--enable-libass}. This filter also requires a build with libavcodec and
8039 libavformat to convert the passed subtitles file to ASS (Advanced Substation
8040 Alpha) subtitles format.
8042 The filter accepts the following options:
8046 Set the filename of the subtitle file to read. It must be specified.
8049 Specify the size of the original video, the video for which the ASS file
8050 was composed. For the syntax of this option, check the "Video size" section in
8051 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
8052 this is necessary to correctly scale the fonts if the aspect ratio has been
8056 Set subtitles input character encoding. @code{subtitles} filter only. Only
8057 useful if not UTF-8.
8059 @item stream_index, si
8060 Set subtitles stream index. @code{subtitles} filter only.
8063 If the first key is not specified, it is assumed that the first value
8064 specifies the @option{filename}.
8066 For example, to render the file @file{sub.srt} on top of the input
8067 video, use the command:
8072 which is equivalent to:
8074 subtitles=filename=sub.srt
8077 To render the default subtitles stream from file @file{video.mkv}, use:
8082 To render the second subtitles stream from that file, use:
8084 subtitles=video.mkv:si=1
8089 Scale the input by 2x and smooth using the Super2xSaI (Scale and
8090 Interpolate) pixel art scaling algorithm.
8092 Useful for enlarging pixel art images without reducing sharpness.
8099 Apply telecine process to the video.
8101 This filter accepts the following options:
8110 The default value is @code{top}.
8114 A string of numbers representing the pulldown pattern you wish to apply.
8115 The default value is @code{23}.
8119 Some typical patterns:
8124 24p: 2332 (preferred)
8131 24p: 222222222223 ("Euro pulldown")
8137 Select the most representative frame in a given sequence of consecutive frames.
8139 The filter accepts the following options:
8143 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
8144 will pick one of them, and then handle the next batch of @var{n} frames until
8145 the end. Default is @code{100}.
8148 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
8149 value will result in a higher memory usage, so a high value is not recommended.
8151 @subsection Examples
8155 Extract one picture each 50 frames:
8161 Complete example of a thumbnail creation with @command{ffmpeg}:
8163 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
8169 Tile several successive frames together.
8171 The filter accepts the following options:
8176 Set the grid size (i.e. the number of lines and columns). For the syntax of
8177 this option, check the "Video size" section in the ffmpeg-utils manual.
8180 Set the maximum number of frames to render in the given area. It must be less
8181 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
8182 the area will be used.
8185 Set the outer border margin in pixels.
8188 Set the inner border thickness (i.e. the number of pixels between frames). For
8189 more advanced padding options (such as having different values for the edges),
8190 refer to the pad video filter.
8193 Specify the color of the unused areaFor the syntax of this option, check the
8194 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
8198 @subsection Examples
8202 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
8204 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
8206 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
8207 duplicating each output frame to accommodate the originally detected frame
8211 Display @code{5} pictures in an area of @code{3x2} frames,
8212 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
8213 mixed flat and named options:
8215 tile=3x2:nb_frames=5:padding=7:margin=2
8221 Perform various types of temporal field interlacing.
8223 Frames are counted starting from 1, so the first input frame is
8226 The filter accepts the following options:
8231 Specify the mode of the interlacing. This option can also be specified
8232 as a value alone. See below for a list of values for this option.
8234 Available values are:
8238 Move odd frames into the upper field, even into the lower field,
8239 generating a double height frame at half frame rate.
8242 Only output even frames, odd frames are dropped, generating a frame with
8243 unchanged height at half frame rate.
8246 Only output odd frames, even frames are dropped, generating a frame with
8247 unchanged height at half frame rate.
8250 Expand each frame to full height, but pad alternate lines with black,
8251 generating a frame with double height at the same input frame rate.
8253 @item interleave_top, 4
8254 Interleave the upper field from odd frames with the lower field from
8255 even frames, generating a frame with unchanged height at half frame rate.
8257 @item interleave_bottom, 5
8258 Interleave the lower field from odd frames with the upper field from
8259 even frames, generating a frame with unchanged height at half frame rate.
8261 @item interlacex2, 6
8262 Double frame rate with unchanged height. Frames are inserted each
8263 containing the second temporal field from the previous input frame and
8264 the first temporal field from the next input frame. This mode relies on
8265 the top_field_first flag. Useful for interlaced video displays with no
8266 field synchronisation.
8269 Numeric values are deprecated but are accepted for backward
8270 compatibility reasons.
8272 Default mode is @code{merge}.
8275 Specify flags influencing the filter process.
8277 Available value for @var{flags} is:
8280 @item low_pass_filter, vlfp
8281 Enable vertical low-pass filtering in the filter.
8282 Vertical low-pass filtering is required when creating an interlaced
8283 destination from a progressive source which contains high-frequency
8284 vertical detail. Filtering will reduce interlace 'twitter' and Moire
8287 Vertical low-pass filtering can only be enabled for @option{mode}
8288 @var{interleave_top} and @var{interleave_bottom}.
8295 Transpose rows with columns in the input video and optionally flip it.
8297 It accepts the following parameters:
8302 Specify the transposition direction.
8304 Can assume the following values:
8306 @item 0, 4, cclock_flip
8307 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
8315 Rotate by 90 degrees clockwise, that is:
8323 Rotate by 90 degrees counterclockwise, that is:
8330 @item 3, 7, clock_flip
8331 Rotate by 90 degrees clockwise and vertically flip, that is:
8339 For values between 4-7, the transposition is only done if the input
8340 video geometry is portrait and not landscape. These values are
8341 deprecated, the @code{passthrough} option should be used instead.
8343 Numerical values are deprecated, and should be dropped in favor of
8347 Do not apply the transposition if the input geometry matches the one
8348 specified by the specified value. It accepts the following values:
8351 Always apply transposition.
8353 Preserve portrait geometry (when @var{height} >= @var{width}).
8355 Preserve landscape geometry (when @var{width} >= @var{height}).
8358 Default value is @code{none}.
8361 For example to rotate by 90 degrees clockwise and preserve portrait
8364 transpose=dir=1:passthrough=portrait
8367 The command above can also be specified as:
8369 transpose=1:portrait
8373 Trim the input so that the output contains one continuous subpart of the input.
8375 It accepts the following parameters:
8378 Specify the time of the start of the kept section, i.e. the frame with the
8379 timestamp @var{start} will be the first frame in the output.
8382 Specify the time of the first frame that will be dropped, i.e. the frame
8383 immediately preceding the one with the timestamp @var{end} will be the last
8384 frame in the output.
8387 This is the same as @var{start}, except this option sets the start timestamp
8388 in timebase units instead of seconds.
8391 This is the same as @var{end}, except this option sets the end timestamp
8392 in timebase units instead of seconds.
8395 The maximum duration of the output in seconds.
8398 The number of the first frame that should be passed to the output.
8401 The number of the first frame that should be dropped.
8404 @option{start}, @option{end}, @option{duration} are expressed as time
8405 duration specifications, check the "Time duration" section in the
8406 ffmpeg-utils manual.
8408 Note that the first two sets of the start/end options and the @option{duration}
8409 option look at the frame timestamp, while the _frame variants simply count the
8410 frames that pass through the filter. Also note that this filter does not modify
8411 the timestamps. If you wish for the output timestamps to start at zero, insert a
8412 setpts filter after the trim filter.
8414 If multiple start or end options are set, this filter tries to be greedy and
8415 keep all the frames that match at least one of the specified constraints. To keep
8416 only the part that matches all the constraints at once, chain multiple trim
8419 The defaults are such that all the input is kept. So it is possible to set e.g.
8420 just the end values to keep everything before the specified time.
8425 Drop everything except the second minute of input:
8427 ffmpeg -i INPUT -vf trim=60:120
8431 Keep only the first second:
8433 ffmpeg -i INPUT -vf trim=duration=1
8441 Sharpen or blur the input video.
8443 It accepts the following parameters:
8446 @item luma_msize_x, lx
8447 Set the luma matrix horizontal size. It must be an odd integer between
8448 3 and 63. The default value is 5.
8450 @item luma_msize_y, ly
8451 Set the luma matrix vertical size. It must be an odd integer between 3
8452 and 63. The default value is 5.
8454 @item luma_amount, la
8455 Set the luma effect strength. It must be a floating point number, reasonable
8456 values lay between -1.5 and 1.5.
8458 Negative values will blur the input video, while positive values will
8459 sharpen it, a value of zero will disable the effect.
8461 Default value is 1.0.
8463 @item chroma_msize_x, cx
8464 Set the chroma matrix horizontal size. It must be an odd integer
8465 between 3 and 63. The default value is 5.
8467 @item chroma_msize_y, cy
8468 Set the chroma matrix vertical size. It must be an odd integer
8469 between 3 and 63. The default value is 5.
8471 @item chroma_amount, ca
8472 Set the chroma effect strength. It must be a floating point number, reasonable
8473 values lay between -1.5 and 1.5.
8475 Negative values will blur the input video, while positive values will
8476 sharpen it, a value of zero will disable the effect.
8478 Default value is 0.0.
8481 If set to 1, specify using OpenCL capabilities, only available if
8482 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
8486 All parameters are optional and default to the equivalent of the
8487 string '5:5:1.0:5:5:0.0'.
8489 @subsection Examples
8493 Apply strong luma sharpen effect:
8495 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
8499 Apply a strong blur of both luma and chroma parameters:
8501 unsharp=7:7:-2:7:7:-2
8505 @anchor{vidstabdetect}
8506 @section vidstabdetect
8508 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
8509 @ref{vidstabtransform} for pass 2.
8511 This filter generates a file with relative translation and rotation
8512 transform information about subsequent frames, which is then used by
8513 the @ref{vidstabtransform} filter.
8515 To enable compilation of this filter you need to configure FFmpeg with
8516 @code{--enable-libvidstab}.
8518 This filter accepts the following options:
8522 Set the path to the file used to write the transforms information.
8523 Default value is @file{transforms.trf}.
8526 Set how shaky the video is and how quick the camera is. It accepts an
8527 integer in the range 1-10, a value of 1 means little shakiness, a
8528 value of 10 means strong shakiness. Default value is 5.
8531 Set the accuracy of the detection process. It must be a value in the
8532 range 1-15. A value of 1 means low accuracy, a value of 15 means high
8533 accuracy. Default value is 15.
8536 Set stepsize of the search process. The region around minimum is
8537 scanned with 1 pixel resolution. Default value is 6.
8540 Set minimum contrast. Below this value a local measurement field is
8541 discarded. Must be a floating point value in the range 0-1. Default
8545 Set reference frame number for tripod mode.
8547 If enabled, the motion of the frames is compared to a reference frame
8548 in the filtered stream, identified by the specified number. The idea
8549 is to compensate all movements in a more-or-less static scene and keep
8550 the camera view absolutely still.
8552 If set to 0, it is disabled. The frames are counted starting from 1.
8555 Show fields and transforms in the resulting frames. It accepts an
8556 integer in the range 0-2. Default value is 0, which disables any
8560 @subsection Examples
8570 Analyze strongly shaky movie and put the results in file
8571 @file{mytransforms.trf}:
8573 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
8577 Visualize the result of internal transformations in the resulting
8580 vidstabdetect=show=1
8584 Analyze a video with medium shakiness using @command{ffmpeg}:
8586 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
8590 @anchor{vidstabtransform}
8591 @section vidstabtransform
8593 Video stabilization/deshaking: pass 2 of 2,
8594 see @ref{vidstabdetect} for pass 1.
8596 Read a file with transform information for each frame and
8597 apply/compensate them. Together with the @ref{vidstabdetect}
8598 filter this can be used to deshake videos. See also
8599 @url{http://public.hronopik.de/vid.stab}. It is important to also use
8600 the unsharp filter, see below.
8602 To enable compilation of this filter you need to configure FFmpeg with
8603 @code{--enable-libvidstab}.
8609 Set path to the file used to read the transforms. Default value is
8610 @file{transforms.trf}).
8613 Set the number of frames (value*2 + 1) used for lowpass filtering the
8614 camera movements. Default value is 10.
8616 For example a number of 10 means that 21 frames are used (10 in the
8617 past and 10 in the future) to smoothen the motion in the video. A
8618 larger values leads to a smoother video, but limits the acceleration
8619 of the camera (pan/tilt movements). 0 is a special case where a
8620 static camera is simulated.
8623 Set the camera path optimization algorithm.
8625 Accepted values are:
8628 gaussian kernel low-pass filter on camera motion (default)
8630 averaging on transformations
8634 Set maximal number of pixels to translate frames. Default value is -1,
8638 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
8639 value is -1, meaning no limit.
8642 Specify how to deal with borders that may be visible due to movement
8645 Available values are:
8648 keep image information from previous frame (default)
8650 fill the border black
8654 Invert transforms if set to 1. Default value is 0.
8657 Consider transforms as relative to previsou frame if set to 1,
8658 absolute if set to 0. Default value is 0.
8661 Set percentage to zoom. A positive value will result in a zoom-in
8662 effect, a negative value in a zoom-out effect. Default value is 0 (no
8666 Set optimal zooming to avoid borders.
8668 Accepted values are:
8673 optimal static zoom value is determined (only very strong movements
8674 will lead to visible borders) (default)
8676 optimal adaptive zoom value is determined (no borders will be
8677 visible), see @option{zoomspeed}
8680 Note that the value given at zoom is added to the one calculated here.
8683 Set percent to zoom maximally each frame (enabled when
8684 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
8688 Specify type of interpolation.
8690 Available values are:
8695 linear only horizontal
8697 linear in both directions (default)
8699 cubic in both directions (slow)
8703 Enable virtual tripod mode if set to 1, which is equivalent to
8704 @code{relative=0:smoothing=0}. Default value is 0.
8706 Use also @code{tripod} option of @ref{vidstabdetect}.
8709 Increase log verbosity if set to 1. Also the detected global motions
8710 are written to the temporary file @file{global_motions.trf}. Default
8714 @subsection Examples
8718 Use @command{ffmpeg} for a typical stabilization with default values:
8720 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
8723 Note the use of the unsharp filter which is always recommended.
8726 Zoom in a bit more and load transform data from a given file:
8728 vidstabtransform=zoom=5:input="mytransforms.trf"
8732 Smoothen the video even more:
8734 vidstabtransform=smoothing=30
8740 Flip the input video vertically.
8742 For example, to vertically flip a video with @command{ffmpeg}:
8744 ffmpeg -i in.avi -vf "vflip" out.avi
8749 Make or reverse a natural vignetting effect.
8751 The filter accepts the following options:
8755 Set lens angle expression as a number of radians.
8757 The value is clipped in the @code{[0,PI/2]} range.
8759 Default value: @code{"PI/5"}
8763 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
8767 Set forward/backward mode.
8769 Available modes are:
8772 The larger the distance from the central point, the darker the image becomes.
8775 The larger the distance from the central point, the brighter the image becomes.
8776 This can be used to reverse a vignette effect, though there is no automatic
8777 detection to extract the lens @option{angle} and other settings (yet). It can
8778 also be used to create a burning effect.
8781 Default value is @samp{forward}.
8784 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
8786 It accepts the following values:
8789 Evaluate expressions only once during the filter initialization.
8792 Evaluate expressions for each incoming frame. This is way slower than the
8793 @samp{init} mode since it requires all the scalers to be re-computed, but it
8794 allows advanced dynamic expressions.
8797 Default value is @samp{init}.
8800 Set dithering to reduce the circular banding effects. Default is @code{1}
8804 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
8805 Setting this value to the SAR of the input will make a rectangular vignetting
8806 following the dimensions of the video.
8808 Default is @code{1/1}.
8811 @subsection Expressions
8813 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
8814 following parameters.
8819 input width and height
8822 the number of input frame, starting from 0
8825 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
8826 @var{TB} units, NAN if undefined
8829 frame rate of the input video, NAN if the input frame rate is unknown
8832 the PTS (Presentation TimeStamp) of the filtered video frame,
8833 expressed in seconds, NAN if undefined
8836 time base of the input video
8840 @subsection Examples
8844 Apply simple strong vignetting effect:
8850 Make a flickering vignetting:
8852 vignette='PI/4+random(1)*PI/50':eval=frame
8859 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
8860 Deinterlacing Filter").
8862 Based on the process described by Martin Weston for BBC R&D, and
8863 implemented based on the de-interlace algorithm written by Jim
8864 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
8865 uses filter coefficients calculated by BBC R&D.
8867 There are two sets of filter coefficients, so called "simple":
8868 and "complex". Which set of filter coefficients is used can
8869 be set by passing an optional parameter:
8873 Set the interlacing filter coefficients. Accepts one of the following values:
8877 Simple filter coefficient set.
8879 More-complex filter coefficient set.
8881 Default value is @samp{complex}.
8884 Specify which frames to deinterlace. Accept one of the following values:
8888 Deinterlace all frames,
8890 Only deinterlace frames marked as interlaced.
8893 Default value is @samp{all}.
8899 Deinterlace the input video ("yadif" means "yet another deinterlacing
8902 It accepts the following parameters:
8908 The interlacing mode to adopt. It accepts one of the following values:
8912 Output one frame for each frame.
8914 Output one frame for each field.
8915 @item 2, send_frame_nospatial
8916 Like @code{send_frame}, but it skips the spatial interlacing check.
8917 @item 3, send_field_nospatial
8918 Like @code{send_field}, but it skips the spatial interlacing check.
8921 The default value is @code{send_frame}.
8924 The picture field parity assumed for the input interlaced video. It accepts one
8925 of the following values:
8929 Assume the top field is first.
8931 Assume the bottom field is first.
8933 Enable automatic detection of field parity.
8936 The default value is @code{auto}.
8937 If the interlacing is unknown or the decoder does not export this information,
8938 top field first will be assumed.
8941 Specify which frames to deinterlace. Accept one of the following
8946 Deinterlace all frames.
8948 Only deinterlace frames marked as interlaced.
8951 The default value is @code{all}.
8956 Apply Zoom & Pan effect.
8958 This filter accepts the following options:
8962 Set the zoom expression. Default is 1.
8966 Set the x and y expression. Default is 0.
8969 Set the duration expression in number of frames.
8970 This sets for how many number of frames effect will last for
8974 Set the output image size, default is 'hd720'.
8977 Each expression can contain the following constants:
9000 Last calculated 'x' and 'y' position from 'x' and 'y' expression
9001 for current input frame.
9005 'x' and 'y' of last output frame of previous input frame or 0 when there was
9006 not yet such frame (first input frame).
9009 Last calculated zoom from 'z' expression for current input frame.
9012 Last calculated zoom of last output frame of previous input frame.
9015 Number of output frames for current input frame. Calculated from 'd' expression
9016 for each input frame.
9019 number of output frames created for previous input frame
9022 Rational number: input width / input height
9028 display aspect ratio
9032 @subsection Examples
9036 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
9038 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
9042 @c man end VIDEO FILTERS
9044 @chapter Video Sources
9045 @c man begin VIDEO SOURCES
9047 Below is a description of the currently available video sources.
9051 Buffer video frames, and make them available to the filter chain.
9053 This source is mainly intended for a programmatic use, in particular
9054 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
9056 It accepts the following parameters:
9061 Specify the size (width and height) of the buffered video frames. For the
9062 syntax of this option, check the "Video size" section in the ffmpeg-utils
9066 The input video width.
9069 The input video height.
9072 A string representing the pixel format of the buffered video frames.
9073 It may be a number corresponding to a pixel format, or a pixel format
9077 Specify the timebase assumed by the timestamps of the buffered frames.
9080 Specify the frame rate expected for the video stream.
9082 @item pixel_aspect, sar
9083 The sample (pixel) aspect ratio of the input video.
9086 Specify the optional parameters to be used for the scale filter which
9087 is automatically inserted when an input change is detected in the
9088 input size or format.
9093 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
9096 will instruct the source to accept video frames with size 320x240 and
9097 with format "yuv410p", assuming 1/24 as the timestamps timebase and
9098 square pixels (1:1 sample aspect ratio).
9099 Since the pixel format with name "yuv410p" corresponds to the number 6
9100 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
9101 this example corresponds to:
9103 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
9106 Alternatively, the options can be specified as a flat string, but this
9107 syntax is deprecated:
9109 @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}]
9113 Create a pattern generated by an elementary cellular automaton.
9115 The initial state of the cellular automaton can be defined through the
9116 @option{filename}, and @option{pattern} options. If such options are
9117 not specified an initial state is created randomly.
9119 At each new frame a new row in the video is filled with the result of
9120 the cellular automaton next generation. The behavior when the whole
9121 frame is filled is defined by the @option{scroll} option.
9123 This source accepts the following options:
9127 Read the initial cellular automaton state, i.e. the starting row, from
9129 In the file, each non-whitespace character is considered an alive
9130 cell, a newline will terminate the row, and further characters in the
9131 file will be ignored.
9134 Read the initial cellular automaton state, i.e. the starting row, from
9135 the specified string.
9137 Each non-whitespace character in the string is considered an alive
9138 cell, a newline will terminate the row, and further characters in the
9139 string will be ignored.
9142 Set the video rate, that is the number of frames generated per second.
9145 @item random_fill_ratio, ratio
9146 Set the random fill ratio for the initial cellular automaton row. It
9147 is a floating point number value ranging from 0 to 1, defaults to
9150 This option is ignored when a file or a pattern is specified.
9152 @item random_seed, seed
9153 Set the seed for filling randomly the initial row, must be an integer
9154 included between 0 and UINT32_MAX. If not specified, or if explicitly
9155 set to -1, the filter will try to use a good random seed on a best
9159 Set the cellular automaton rule, it is a number ranging from 0 to 255.
9160 Default value is 110.
9163 Set the size of the output video. For the syntax of this option, check
9164 the "Video size" section in the ffmpeg-utils manual.
9166 If @option{filename} or @option{pattern} is specified, the size is set
9167 by default to the width of the specified initial state row, and the
9168 height is set to @var{width} * PHI.
9170 If @option{size} is set, it must contain the width of the specified
9171 pattern string, and the specified pattern will be centered in the
9174 If a filename or a pattern string is not specified, the size value
9175 defaults to "320x518" (used for a randomly generated initial state).
9178 If set to 1, scroll the output upward when all the rows in the output
9179 have been already filled. If set to 0, the new generated row will be
9180 written over the top row just after the bottom row is filled.
9183 @item start_full, full
9184 If set to 1, completely fill the output with generated rows before
9185 outputting the first frame.
9186 This is the default behavior, for disabling set the value to 0.
9189 If set to 1, stitch the left and right row edges together.
9190 This is the default behavior, for disabling set the value to 0.
9193 @subsection Examples
9197 Read the initial state from @file{pattern}, and specify an output of
9200 cellauto=f=pattern:s=200x400
9204 Generate a random initial row with a width of 200 cells, with a fill
9207 cellauto=ratio=2/3:s=200x200
9211 Create a pattern generated by rule 18 starting by a single alive cell
9212 centered on an initial row with width 100:
9214 cellauto=p=@@:s=100x400:full=0:rule=18
9218 Specify a more elaborated initial pattern:
9220 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
9227 Generate a Mandelbrot set fractal, and progressively zoom towards the
9228 point specified with @var{start_x} and @var{start_y}.
9230 This source accepts the following options:
9235 Set the terminal pts value. Default value is 400.
9238 Set the terminal scale value.
9239 Must be a floating point value. Default value is 0.3.
9242 Set the inner coloring mode, that is the algorithm used to draw the
9243 Mandelbrot fractal internal region.
9245 It shall assume one of the following values:
9250 Show time until convergence.
9252 Set color based on point closest to the origin of the iterations.
9257 Default value is @var{mincol}.
9260 Set the bailout value. Default value is 10.0.
9263 Set the maximum of iterations performed by the rendering
9264 algorithm. Default value is 7189.
9267 Set outer coloring mode.
9268 It shall assume one of following values:
9270 @item iteration_count
9271 Set iteration cound mode.
9272 @item normalized_iteration_count
9273 set normalized iteration count mode.
9275 Default value is @var{normalized_iteration_count}.
9278 Set frame rate, expressed as number of frames per second. Default
9282 Set frame size. For the syntax of this option, check the "Video
9283 size" section in the ffmpeg-utils manual. Default value is "640x480".
9286 Set the initial scale value. Default value is 3.0.
9289 Set the initial x position. Must be a floating point value between
9290 -100 and 100. Default value is -0.743643887037158704752191506114774.
9293 Set the initial y position. Must be a floating point value between
9294 -100 and 100. Default value is -0.131825904205311970493132056385139.
9299 Generate various test patterns, as generated by the MPlayer test filter.
9301 The size of the generated video is fixed, and is 256x256.
9302 This source is useful in particular for testing encoding features.
9304 This source accepts the following options:
9309 Specify the frame rate of the sourced video, as the number of frames
9310 generated per second. It has to be a string in the format
9311 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9312 number or a valid video frame rate abbreviation. The default value is
9316 Set the video duration of the sourced video. The accepted syntax is:
9321 See also the function @code{av_parse_time()}.
9323 If not specified, or the expressed duration is negative, the video is
9324 supposed to be generated forever.
9328 Set the number or the name of the test to perform. Supported tests are:
9344 Default value is "all", which will cycle through the list of all tests.
9352 will generate a "dc_luma" test pattern.
9356 Provide a frei0r source.
9358 To enable compilation of this filter you need to install the frei0r
9359 header and configure FFmpeg with @code{--enable-frei0r}.
9361 This source accepts the following parameters:
9366 The size of the video to generate. For the syntax of this option, check the
9367 "Video size" section in the ffmpeg-utils manual.
9370 The framerate of the generated video. It may be a string of the form
9371 @var{num}/@var{den} or a frame rate abbreviation.
9374 The name to the frei0r source to load. For more information regarding frei0r and
9375 how to set the parameters, read the @ref{frei0r} section in the video filters
9379 A '|'-separated list of parameters to pass to the frei0r source.
9383 For example, to generate a frei0r partik0l source with size 200x200
9384 and frame rate 10 which is overlayed on the overlay filter main input:
9386 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
9391 Generate a life pattern.
9393 This source is based on a generalization of John Conway's life game.
9395 The sourced input represents a life grid, each pixel represents a cell
9396 which can be in one of two possible states, alive or dead. Every cell
9397 interacts with its eight neighbours, which are the cells that are
9398 horizontally, vertically, or diagonally adjacent.
9400 At each interaction the grid evolves according to the adopted rule,
9401 which specifies the number of neighbor alive cells which will make a
9402 cell stay alive or born. The @option{rule} option allows one to specify
9405 This source accepts the following options:
9409 Set the file from which to read the initial grid state. In the file,
9410 each non-whitespace character is considered an alive cell, and newline
9411 is used to delimit the end of each row.
9413 If this option is not specified, the initial grid is generated
9417 Set the video rate, that is the number of frames generated per second.
9420 @item random_fill_ratio, ratio
9421 Set the random fill ratio for the initial random grid. It is a
9422 floating point number value ranging from 0 to 1, defaults to 1/PHI.
9423 It is ignored when a file is specified.
9425 @item random_seed, seed
9426 Set the seed for filling the initial random grid, must be an integer
9427 included between 0 and UINT32_MAX. If not specified, or if explicitly
9428 set to -1, the filter will try to use a good random seed on a best
9434 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
9435 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
9436 @var{NS} specifies the number of alive neighbor cells which make a
9437 live cell stay alive, and @var{NB} the number of alive neighbor cells
9438 which make a dead cell to become alive (i.e. to "born").
9439 "s" and "b" can be used in place of "S" and "B", respectively.
9441 Alternatively a rule can be specified by an 18-bits integer. The 9
9442 high order bits are used to encode the next cell state if it is alive
9443 for each number of neighbor alive cells, the low order bits specify
9444 the rule for "borning" new cells. Higher order bits encode for an
9445 higher number of neighbor cells.
9446 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
9447 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
9449 Default value is "S23/B3", which is the original Conway's game of life
9450 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
9451 cells, and will born a new cell if there are three alive cells around
9455 Set the size of the output video. For the syntax of this option, check the
9456 "Video size" section in the ffmpeg-utils manual.
9458 If @option{filename} is specified, the size is set by default to the
9459 same size of the input file. If @option{size} is set, it must contain
9460 the size specified in the input file, and the initial grid defined in
9461 that file is centered in the larger resulting area.
9463 If a filename is not specified, the size value defaults to "320x240"
9464 (used for a randomly generated initial grid).
9467 If set to 1, stitch the left and right grid edges together, and the
9468 top and bottom edges also. Defaults to 1.
9471 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
9472 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
9473 value from 0 to 255.
9476 Set the color of living (or new born) cells.
9479 Set the color of dead cells. If @option{mold} is set, this is the first color
9480 used to represent a dead cell.
9483 Set mold color, for definitely dead and moldy cells.
9485 For the syntax of these 3 color options, check the "Color" section in the
9486 ffmpeg-utils manual.
9489 @subsection Examples
9493 Read a grid from @file{pattern}, and center it on a grid of size
9496 life=f=pattern:s=300x300
9500 Generate a random grid of size 200x200, with a fill ratio of 2/3:
9502 life=ratio=2/3:s=200x200
9506 Specify a custom rule for evolving a randomly generated grid:
9512 Full example with slow death effect (mold) using @command{ffplay}:
9514 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
9519 @anchor{haldclutsrc}
9523 @anchor{smptehdbars}
9525 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
9527 The @code{color} source provides an uniformly colored input.
9529 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
9530 @ref{haldclut} filter.
9532 The @code{nullsrc} source returns unprocessed video frames. It is
9533 mainly useful to be employed in analysis / debugging tools, or as the
9534 source for filters which ignore the input data.
9536 The @code{rgbtestsrc} source generates an RGB test pattern useful for
9537 detecting RGB vs BGR issues. You should see a red, green and blue
9538 stripe from top to bottom.
9540 The @code{smptebars} source generates a color bars pattern, based on
9541 the SMPTE Engineering Guideline EG 1-1990.
9543 The @code{smptehdbars} source generates a color bars pattern, based on
9544 the SMPTE RP 219-2002.
9546 The @code{testsrc} source generates a test video pattern, showing a
9547 color pattern, a scrolling gradient and a timestamp. This is mainly
9548 intended for testing purposes.
9550 The sources accept the following parameters:
9555 Specify the color of the source, only available in the @code{color}
9556 source. For the syntax of this option, check the "Color" section in the
9557 ffmpeg-utils manual.
9560 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
9561 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
9562 pixels to be used as identity matrix for 3D lookup tables. Each component is
9563 coded on a @code{1/(N*N)} scale.
9566 Specify the size of the sourced video. For the syntax of this option, check the
9567 "Video size" section in the ffmpeg-utils manual. The default value is
9570 This option is not available with the @code{haldclutsrc} filter.
9573 Specify the frame rate of the sourced video, as the number of frames
9574 generated per second. It has to be a string in the format
9575 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9576 number or a valid video frame rate abbreviation. The default value is
9580 Set the sample aspect ratio of the sourced video.
9583 Set the video duration of the sourced video. The accepted syntax is:
9585 [-]HH[:MM[:SS[.m...]]]
9588 Also see the the @code{av_parse_time()} function.
9590 If not specified, or the expressed duration is negative, the video is
9591 supposed to be generated forever.
9594 Set the number of decimals to show in the timestamp, only available in the
9595 @code{testsrc} source.
9597 The displayed timestamp value will correspond to the original
9598 timestamp value multiplied by the power of 10 of the specified
9599 value. Default value is 0.
9602 For example the following:
9604 testsrc=duration=5.3:size=qcif:rate=10
9607 will generate a video with a duration of 5.3 seconds, with size
9608 176x144 and a frame rate of 10 frames per second.
9610 The following graph description will generate a red source
9611 with an opacity of 0.2, with size "qcif" and a frame rate of 10
9614 color=c=red@@0.2:s=qcif:r=10
9617 If the input content is to be ignored, @code{nullsrc} can be used. The
9618 following command generates noise in the luminance plane by employing
9619 the @code{geq} filter:
9621 nullsrc=s=256x256, geq=random(1)*255:128:128
9624 @subsection Commands
9626 The @code{color} source supports the following commands:
9630 Set the color of the created image. Accepts the same syntax of the
9631 corresponding @option{color} option.
9634 @c man end VIDEO SOURCES
9636 @chapter Video Sinks
9637 @c man begin VIDEO SINKS
9639 Below is a description of the currently available video sinks.
9643 Buffer video frames, and make them available to the end of the filter
9646 This sink is mainly intended for programmatic use, in particular
9647 through the interface defined in @file{libavfilter/buffersink.h}
9648 or the options system.
9650 It accepts a pointer to an AVBufferSinkContext structure, which
9651 defines the incoming buffers' formats, to be passed as the opaque
9652 parameter to @code{avfilter_init_filter} for initialization.
9656 Null video sink: do absolutely nothing with the input video. It is
9657 mainly useful as a template and for use in analysis / debugging
9660 @c man end VIDEO SINKS
9662 @chapter Multimedia Filters
9663 @c man begin MULTIMEDIA FILTERS
9665 Below is a description of the currently available multimedia filters.
9667 @section avectorscope
9669 Convert input audio to a video output, representing the audio vector
9672 The filter is used to measure the difference between channels of stereo
9673 audio stream. A monoaural signal, consisting of identical left and right
9674 signal, results in straight vertical line. Any stereo separation is visible
9675 as a deviation from this line, creating a Lissajous figure.
9676 If the straight (or deviation from it) but horizontal line appears this
9677 indicates that the left and right channels are out of phase.
9679 The filter accepts the following options:
9683 Set the vectorscope mode.
9685 Available values are:
9688 Lissajous rotated by 45 degrees.
9691 Same as above but not rotated.
9694 Default value is @samp{lissajous}.
9697 Set the video size for the output. For the syntax of this option, check the "Video size"
9698 section in the ffmpeg-utils manual. Default value is @code{400x400}.
9701 Set the output frame rate. Default value is @code{25}.
9706 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
9707 Allowed range is @code{[0, 255]}.
9712 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
9713 Allowed range is @code{[0, 255]}.
9716 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
9719 @subsection Examples
9723 Complete example using @command{ffplay}:
9725 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9726 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
9732 Concatenate audio and video streams, joining them together one after the
9735 The filter works on segments of synchronized video and audio streams. All
9736 segments must have the same number of streams of each type, and that will
9737 also be the number of streams at output.
9739 The filter accepts the following options:
9744 Set the number of segments. Default is 2.
9747 Set the number of output video streams, that is also the number of video
9748 streams in each segment. Default is 1.
9751 Set the number of output audio streams, that is also the number of audio
9752 streams in each segment. Default is 0.
9755 Activate unsafe mode: do not fail if segments have a different format.
9759 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
9760 @var{a} audio outputs.
9762 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
9763 segment, in the same order as the outputs, then the inputs for the second
9766 Related streams do not always have exactly the same duration, for various
9767 reasons including codec frame size or sloppy authoring. For that reason,
9768 related synchronized streams (e.g. a video and its audio track) should be
9769 concatenated at once. The concat filter will use the duration of the longest
9770 stream in each segment (except the last one), and if necessary pad shorter
9771 audio streams with silence.
9773 For this filter to work correctly, all segments must start at timestamp 0.
9775 All corresponding streams must have the same parameters in all segments; the
9776 filtering system will automatically select a common pixel format for video
9777 streams, and a common sample format, sample rate and channel layout for
9778 audio streams, but other settings, such as resolution, must be converted
9779 explicitly by the user.
9781 Different frame rates are acceptable but will result in variable frame rate
9782 at output; be sure to configure the output file to handle it.
9784 @subsection Examples
9788 Concatenate an opening, an episode and an ending, all in bilingual version
9789 (video in stream 0, audio in streams 1 and 2):
9791 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
9792 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
9793 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
9794 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
9798 Concatenate two parts, handling audio and video separately, using the
9799 (a)movie sources, and adjusting the resolution:
9801 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
9802 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
9803 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
9805 Note that a desync will happen at the stitch if the audio and video streams
9806 do not have exactly the same duration in the first file.
9812 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
9813 it unchanged. By default, it logs a message at a frequency of 10Hz with the
9814 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
9815 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
9817 The filter also has a video output (see the @var{video} option) with a real
9818 time graph to observe the loudness evolution. The graphic contains the logged
9819 message mentioned above, so it is not printed anymore when this option is set,
9820 unless the verbose logging is set. The main graphing area contains the
9821 short-term loudness (3 seconds of analysis), and the gauge on the right is for
9822 the momentary loudness (400 milliseconds).
9824 More information about the Loudness Recommendation EBU R128 on
9825 @url{http://tech.ebu.ch/loudness}.
9827 The filter accepts the following options:
9832 Activate the video output. The audio stream is passed unchanged whether this
9833 option is set or no. The video stream will be the first output stream if
9834 activated. Default is @code{0}.
9837 Set the video size. This option is for video only. For the syntax of this
9838 option, check the "Video size" section in the ffmpeg-utils manual. Default
9839 and minimum resolution is @code{640x480}.
9842 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
9843 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
9844 other integer value between this range is allowed.
9847 Set metadata injection. If set to @code{1}, the audio input will be segmented
9848 into 100ms output frames, each of them containing various loudness information
9849 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
9851 Default is @code{0}.
9854 Force the frame logging level.
9856 Available values are:
9859 information logging level
9861 verbose logging level
9864 By default, the logging level is set to @var{info}. If the @option{video} or
9865 the @option{metadata} options are set, it switches to @var{verbose}.
9870 Available modes can be cumulated (the option is a @code{flag} type). Possible
9874 Disable any peak mode (default).
9876 Enable sample-peak mode.
9878 Simple peak mode looking for the higher sample value. It logs a message
9879 for sample-peak (identified by @code{SPK}).
9881 Enable true-peak mode.
9883 If enabled, the peak lookup is done on an over-sampled version of the input
9884 stream for better peak accuracy. It logs a message for true-peak.
9885 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
9886 This mode requires a build with @code{libswresample}.
9891 @subsection Examples
9895 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
9897 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
9901 Run an analysis with @command{ffmpeg}:
9903 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
9907 @section interleave, ainterleave
9909 Temporally interleave frames from several inputs.
9911 @code{interleave} works with video inputs, @code{ainterleave} with audio.
9913 These filters read frames from several inputs and send the oldest
9914 queued frame to the output.
9916 Input streams must have a well defined, monotonically increasing frame
9919 In order to submit one frame to output, these filters need to enqueue
9920 at least one frame for each input, so they cannot work in case one
9921 input is not yet terminated and will not receive incoming frames.
9923 For example consider the case when one input is a @code{select} filter
9924 which always drop input frames. The @code{interleave} filter will keep
9925 reading from that input, but it will never be able to send new frames
9926 to output until the input will send an end-of-stream signal.
9928 Also, depending on inputs synchronization, the filters will drop
9929 frames in case one input receives more frames than the other ones, and
9930 the queue is already filled.
9932 These filters accept the following options:
9936 Set the number of different inputs, it is 2 by default.
9939 @subsection Examples
9943 Interleave frames belonging to different streams using @command{ffmpeg}:
9945 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
9949 Add flickering blur effect:
9951 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
9955 @section perms, aperms
9957 Set read/write permissions for the output frames.
9959 These filters are mainly aimed at developers to test direct path in the
9960 following filter in the filtergraph.
9962 The filters accept the following options:
9966 Select the permissions mode.
9968 It accepts the following values:
9971 Do nothing. This is the default.
9973 Set all the output frames read-only.
9975 Set all the output frames directly writable.
9977 Make the frame read-only if writable, and writable if read-only.
9979 Set each output frame read-only or writable randomly.
9983 Set the seed for the @var{random} mode, must be an integer included between
9984 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
9985 @code{-1}, the filter will try to use a good random seed on a best effort
9989 Note: in case of auto-inserted filter between the permission filter and the
9990 following one, the permission might not be received as expected in that
9991 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
9992 perms/aperms filter can avoid this problem.
9994 @section select, aselect
9996 Select frames to pass in output.
9998 This filter accepts the following options:
10003 Set expression, which is evaluated for each input frame.
10005 If the expression is evaluated to zero, the frame is discarded.
10007 If the evaluation result is negative or NaN, the frame is sent to the
10008 first output; otherwise it is sent to the output with index
10009 @code{ceil(val)-1}, assuming that the input index starts from 0.
10011 For example a value of @code{1.2} corresponds to the output with index
10012 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
10015 Set the number of outputs. The output to which to send the selected
10016 frame is based on the result of the evaluation. Default value is 1.
10019 The expression can contain the following constants:
10023 The (sequential) number of the filtered frame, starting from 0.
10026 The (sequential) number of the selected frame, starting from 0.
10028 @item prev_selected_n
10029 The sequential number of the last selected frame. It's NAN if undefined.
10032 The timebase of the input timestamps.
10035 The PTS (Presentation TimeStamp) of the filtered video frame,
10036 expressed in @var{TB} units. It's NAN if undefined.
10039 The PTS of the filtered video frame,
10040 expressed in seconds. It's NAN if undefined.
10043 The PTS of the previously filtered video frame. It's NAN if undefined.
10045 @item prev_selected_pts
10046 The PTS of the last previously filtered video frame. It's NAN if undefined.
10048 @item prev_selected_t
10049 The PTS of the last previously selected video frame. It's NAN if undefined.
10052 The PTS of the first video frame in the video. It's NAN if undefined.
10055 The time of the first video frame in the video. It's NAN if undefined.
10057 @item pict_type @emph{(video only)}
10058 The type of the filtered frame. It can assume one of the following
10070 @item interlace_type @emph{(video only)}
10071 The frame interlace type. It can assume one of the following values:
10074 The frame is progressive (not interlaced).
10076 The frame is top-field-first.
10078 The frame is bottom-field-first.
10081 @item consumed_sample_n @emph{(audio only)}
10082 the number of selected samples before the current frame
10084 @item samples_n @emph{(audio only)}
10085 the number of samples in the current frame
10087 @item sample_rate @emph{(audio only)}
10088 the input sample rate
10091 This is 1 if the filtered frame is a key-frame, 0 otherwise.
10094 the position in the file of the filtered frame, -1 if the information
10095 is not available (e.g. for synthetic video)
10097 @item scene @emph{(video only)}
10098 value between 0 and 1 to indicate a new scene; a low value reflects a low
10099 probability for the current frame to introduce a new scene, while a higher
10100 value means the current frame is more likely to be one (see the example below)
10104 The default value of the select expression is "1".
10106 @subsection Examples
10110 Select all frames in input:
10115 The example above is the same as:
10127 Select only I-frames:
10129 select='eq(pict_type\,I)'
10133 Select one frame every 100:
10135 select='not(mod(n\,100))'
10139 Select only frames contained in the 10-20 time interval:
10141 select=between(t\,10\,20)
10145 Select only I frames contained in the 10-20 time interval:
10147 select=between(t\,10\,20)*eq(pict_type\,I)
10151 Select frames with a minimum distance of 10 seconds:
10153 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
10157 Use aselect to select only audio frames with samples number > 100:
10159 aselect='gt(samples_n\,100)'
10163 Create a mosaic of the first scenes:
10165 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
10168 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
10172 Send even and odd frames to separate outputs, and compose them:
10174 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
10178 @section sendcmd, asendcmd
10180 Send commands to filters in the filtergraph.
10182 These filters read commands to be sent to other filters in the
10185 @code{sendcmd} must be inserted between two video filters,
10186 @code{asendcmd} must be inserted between two audio filters, but apart
10187 from that they act the same way.
10189 The specification of commands can be provided in the filter arguments
10190 with the @var{commands} option, or in a file specified by the
10191 @var{filename} option.
10193 These filters accept the following options:
10196 Set the commands to be read and sent to the other filters.
10198 Set the filename of the commands to be read and sent to the other
10202 @subsection Commands syntax
10204 A commands description consists of a sequence of interval
10205 specifications, comprising a list of commands to be executed when a
10206 particular event related to that interval occurs. The occurring event
10207 is typically the current frame time entering or leaving a given time
10210 An interval is specified by the following syntax:
10212 @var{START}[-@var{END}] @var{COMMANDS};
10215 The time interval is specified by the @var{START} and @var{END} times.
10216 @var{END} is optional and defaults to the maximum time.
10218 The current frame time is considered within the specified interval if
10219 it is included in the interval [@var{START}, @var{END}), that is when
10220 the time is greater or equal to @var{START} and is lesser than
10223 @var{COMMANDS} consists of a sequence of one or more command
10224 specifications, separated by ",", relating to that interval. The
10225 syntax of a command specification is given by:
10227 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
10230 @var{FLAGS} is optional and specifies the type of events relating to
10231 the time interval which enable sending the specified command, and must
10232 be a non-null sequence of identifier flags separated by "+" or "|" and
10233 enclosed between "[" and "]".
10235 The following flags are recognized:
10238 The command is sent when the current frame timestamp enters the
10239 specified interval. In other words, the command is sent when the
10240 previous frame timestamp was not in the given interval, and the
10244 The command is sent when the current frame timestamp leaves the
10245 specified interval. In other words, the command is sent when the
10246 previous frame timestamp was in the given interval, and the
10250 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
10253 @var{TARGET} specifies the target of the command, usually the name of
10254 the filter class or a specific filter instance name.
10256 @var{COMMAND} specifies the name of the command for the target filter.
10258 @var{ARG} is optional and specifies the optional list of argument for
10259 the given @var{COMMAND}.
10261 Between one interval specification and another, whitespaces, or
10262 sequences of characters starting with @code{#} until the end of line,
10263 are ignored and can be used to annotate comments.
10265 A simplified BNF description of the commands specification syntax
10268 @var{COMMAND_FLAG} ::= "enter" | "leave"
10269 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
10270 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
10271 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
10272 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
10273 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
10276 @subsection Examples
10280 Specify audio tempo change at second 4:
10282 asendcmd=c='4.0 atempo tempo 1.5',atempo
10286 Specify a list of drawtext and hue commands in a file.
10288 # show text in the interval 5-10
10289 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
10290 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
10292 # desaturate the image in the interval 15-20
10293 15.0-20.0 [enter] hue s 0,
10294 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
10296 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
10298 # apply an exponential saturation fade-out effect, starting from time 25
10299 25 [enter] hue s exp(25-t)
10302 A filtergraph allowing to read and process the above command list
10303 stored in a file @file{test.cmd}, can be specified with:
10305 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
10310 @section setpts, asetpts
10312 Change the PTS (presentation timestamp) of the input frames.
10314 @code{setpts} works on video frames, @code{asetpts} on audio frames.
10316 This filter accepts the following options:
10321 The expression which is evaluated for each frame to construct its timestamp.
10325 The expression is evaluated through the eval API and can contain the following
10330 frame rate, only defined for constant frame-rate video
10333 The presentation timestamp in input
10336 The count of the input frame for video or the number of consumed samples,
10337 not including the current frame for audio, starting from 0.
10339 @item NB_CONSUMED_SAMPLES
10340 The number of consumed samples, not including the current frame (only
10343 @item NB_SAMPLES, S
10344 The number of samples in the current frame (only audio)
10346 @item SAMPLE_RATE, SR
10347 The audio sample rate.
10350 The PTS of the first frame.
10353 the time in seconds of the first frame
10356 State whether the current frame is interlaced.
10359 the time in seconds of the current frame
10362 original position in the file of the frame, or undefined if undefined
10363 for the current frame
10366 The previous input PTS.
10369 previous input time in seconds
10372 The previous output PTS.
10375 previous output time in seconds
10378 The wallclock (RTC) time in microseconds.. This is deprecated, use time(0)
10382 The wallclock (RTC) time at the start of the movie in microseconds.
10385 The timebase of the input timestamps.
10389 @subsection Examples
10393 Start counting PTS from zero
10395 setpts=PTS-STARTPTS
10399 Apply fast motion effect:
10405 Apply slow motion effect:
10411 Set fixed rate of 25 frames per second:
10417 Set fixed rate 25 fps with some jitter:
10419 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
10423 Apply an offset of 10 seconds to the input PTS:
10429 Generate timestamps from a "live source" and rebase onto the current timebase:
10431 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
10435 Generate timestamps by counting samples:
10442 @section settb, asettb
10444 Set the timebase to use for the output frames timestamps.
10445 It is mainly useful for testing timebase configuration.
10447 It accepts the following parameters:
10452 The expression which is evaluated into the output timebase.
10456 The value for @option{tb} is an arithmetic expression representing a
10457 rational. The expression can contain the constants "AVTB" (the default
10458 timebase), "intb" (the input timebase) and "sr" (the sample rate,
10459 audio only). Default value is "intb".
10461 @subsection Examples
10465 Set the timebase to 1/25:
10471 Set the timebase to 1/10:
10477 Set the timebase to 1001/1000:
10483 Set the timebase to 2*intb:
10489 Set the default timebase value:
10496 Convert input audio to a video output representing
10497 frequency spectrum logarithmically (using constant Q transform with
10498 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
10500 The filter accepts the following options:
10504 Specify the transform volume (multiplier). Acceptable value is [1.0, 100.0].
10505 Default value is @code{16.0}.
10508 Specify the transform timeclamp. At low frequency, there is trade-off between
10509 accuracy in time domain and frequency domain. If timeclamp is lower,
10510 event in time domain is represented more accurately (such as fast bass drum),
10511 otherwise event in frequency domain is represented more accurately
10512 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
10515 Specify the transform coeffclamp. If coeffclamp is lower, transform is
10516 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
10517 Default value is @code{1.0}.
10520 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
10521 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
10522 Default value is @code{3.0}.
10525 Specify font file for use with freetype. If not specified, use embedded font.
10528 If set to 1 (the default), the video size is 1920x1080 (full HD),
10529 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
10532 Specify video fps. Default value is @code{25}.
10535 Specify number of transform per frame, so there are fps*count transforms
10536 per second. Note that audio data rate must be divisible by fps*count.
10537 Default value is @code{6}.
10541 @subsection Examples
10545 Playing audio while showing the spectrum:
10547 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
10551 Same as above, but with frame rate 30 fps:
10553 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
10557 Playing at 960x540 and lower CPU usage:
10559 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
10563 A1 and its harmonics: A1, A2, (near)E3, A3:
10565 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),
10566 asplit[a][out1]; [a] showcqt [out0]'
10570 Same as above, but with more accuracy in frequency domain (and slower):
10572 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),
10573 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
10578 @section showspectrum
10580 Convert input audio to a video output, representing the audio frequency
10583 The filter accepts the following options:
10587 Specify the video size for the output. For the syntax of this option, check
10588 the "Video size" section in the ffmpeg-utils manual. Default value is
10592 Specify if the spectrum should slide along the window. Default value is
10596 Specify display mode.
10598 It accepts the following values:
10601 all channels are displayed in the same row
10603 all channels are displayed in separate rows
10606 Default value is @samp{combined}.
10609 Specify display color mode.
10611 It accepts the following values:
10614 each channel is displayed in a separate color
10616 each channel is is displayed using the same color scheme
10619 Default value is @samp{channel}.
10622 Specify scale used for calculating intensity color values.
10624 It accepts the following values:
10629 square root, default
10636 Default value is @samp{sqrt}.
10639 Set saturation modifier for displayed colors. Negative values provide
10640 alternative color scheme. @code{0} is no saturation at all.
10641 Saturation must be in [-10.0, 10.0] range.
10642 Default value is @code{1}.
10645 Set window function.
10647 It accepts the following values:
10650 No samples pre-processing (do not expect this to be faster)
10659 Default value is @code{hann}.
10662 The usage is very similar to the showwaves filter; see the examples in that
10665 @subsection Examples
10669 Large window with logarithmic color scaling:
10671 showspectrum=s=1280x480:scale=log
10675 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
10677 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10678 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
10684 Convert input audio to a video output, representing the samples waves.
10686 The filter accepts the following options:
10690 Specify the video size for the output. For the syntax of this option, check
10691 the "Video size" section in the ffmpeg-utils manual. Default value
10697 Available values are:
10700 Draw a point for each sample.
10703 Draw a vertical line for each sample.
10706 Draw a point for each sample and a line between them.
10709 Default value is @code{point}.
10712 Set the number of samples which are printed on the same column. A
10713 larger value will decrease the frame rate. Must be a positive
10714 integer. This option can be set only if the value for @var{rate}
10715 is not explicitly specified.
10718 Set the (approximate) output frame rate. This is done by setting the
10719 option @var{n}. Default value is "25".
10723 @subsection Examples
10727 Output the input file audio and the corresponding video representation
10730 amovie=a.mp3,asplit[out0],showwaves[out1]
10734 Create a synthetic signal and show it with showwaves, forcing a
10735 frame rate of 30 frames per second:
10737 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
10741 @section split, asplit
10743 Split input into several identical outputs.
10745 @code{asplit} works with audio input, @code{split} with video.
10747 The filter accepts a single parameter which specifies the number of outputs. If
10748 unspecified, it defaults to 2.
10750 @subsection Examples
10754 Create two separate outputs from the same input:
10756 [in] split [out0][out1]
10760 To create 3 or more outputs, you need to specify the number of
10763 [in] asplit=3 [out0][out1][out2]
10767 Create two separate outputs from the same input, one cropped and
10770 [in] split [splitout1][splitout2];
10771 [splitout1] crop=100:100:0:0 [cropout];
10772 [splitout2] pad=200:200:100:100 [padout];
10776 Create 5 copies of the input audio with @command{ffmpeg}:
10778 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
10784 Receive commands sent through a libzmq client, and forward them to
10785 filters in the filtergraph.
10787 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
10788 must be inserted between two video filters, @code{azmq} between two
10791 To enable these filters you need to install the libzmq library and
10792 headers and configure FFmpeg with @code{--enable-libzmq}.
10794 For more information about libzmq see:
10795 @url{http://www.zeromq.org/}
10797 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
10798 receives messages sent through a network interface defined by the
10799 @option{bind_address} option.
10801 The received message must be in the form:
10803 @var{TARGET} @var{COMMAND} [@var{ARG}]
10806 @var{TARGET} specifies the target of the command, usually the name of
10807 the filter class or a specific filter instance name.
10809 @var{COMMAND} specifies the name of the command for the target filter.
10811 @var{ARG} is optional and specifies the optional argument list for the
10812 given @var{COMMAND}.
10814 Upon reception, the message is processed and the corresponding command
10815 is injected into the filtergraph. Depending on the result, the filter
10816 will send a reply to the client, adopting the format:
10818 @var{ERROR_CODE} @var{ERROR_REASON}
10822 @var{MESSAGE} is optional.
10824 @subsection Examples
10826 Look at @file{tools/zmqsend} for an example of a zmq client which can
10827 be used to send commands processed by these filters.
10829 Consider the following filtergraph generated by @command{ffplay}
10831 ffplay -dumpgraph 1 -f lavfi "
10832 color=s=100x100:c=red [l];
10833 color=s=100x100:c=blue [r];
10834 nullsrc=s=200x100, zmq [bg];
10835 [bg][l] overlay [bg+l];
10836 [bg+l][r] overlay=x=100 "
10839 To change the color of the left side of the video, the following
10840 command can be used:
10842 echo Parsed_color_0 c yellow | tools/zmqsend
10845 To change the right side:
10847 echo Parsed_color_1 c pink | tools/zmqsend
10850 @c man end MULTIMEDIA FILTERS
10852 @chapter Multimedia Sources
10853 @c man begin MULTIMEDIA SOURCES
10855 Below is a description of the currently available multimedia sources.
10859 This is the same as @ref{movie} source, except it selects an audio
10865 Read audio and/or video stream(s) from a movie container.
10867 It accepts the following parameters:
10871 The name of the resource to read (not necessarily a file; it can also be a
10872 device or a stream accessed through some protocol).
10874 @item format_name, f
10875 Specifies the format assumed for the movie to read, and can be either
10876 the name of a container or an input device. If not specified, the
10877 format is guessed from @var{movie_name} or by probing.
10879 @item seek_point, sp
10880 Specifies the seek point in seconds. The frames will be output
10881 starting from this seek point. The parameter is evaluated with
10882 @code{av_strtod}, so the numerical value may be suffixed by an IS
10883 postfix. The default value is "0".
10886 Specifies the streams to read. Several streams can be specified,
10887 separated by "+". The source will then have as many outputs, in the
10888 same order. The syntax is explained in the ``Stream specifiers''
10889 section in the ffmpeg manual. Two special names, "dv" and "da" specify
10890 respectively the default (best suited) video and audio stream. Default
10891 is "dv", or "da" if the filter is called as "amovie".
10893 @item stream_index, si
10894 Specifies the index of the video stream to read. If the value is -1,
10895 the most suitable video stream will be automatically selected. The default
10896 value is "-1". Deprecated. If the filter is called "amovie", it will select
10897 audio instead of video.
10900 Specifies how many times to read the stream in sequence.
10901 If the value is less than 1, the stream will be read again and again.
10902 Default value is "1".
10904 Note that when the movie is looped the source timestamps are not
10905 changed, so it will generate non monotonically increasing timestamps.
10908 It allows overlaying a second video on top of the main input of
10909 a filtergraph, as shown in this graph:
10911 input -----------> deltapts0 --> overlay --> output
10914 movie --> scale--> deltapts1 -------+
10916 @subsection Examples
10920 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
10921 on top of the input labelled "in":
10923 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
10924 [in] setpts=PTS-STARTPTS [main];
10925 [main][over] overlay=16:16 [out]
10929 Read from a video4linux2 device, and overlay it on top of the input
10932 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
10933 [in] setpts=PTS-STARTPTS [main];
10934 [main][over] overlay=16:16 [out]
10938 Read the first video stream and the audio stream with id 0x81 from
10939 dvd.vob; the video is connected to the pad named "video" and the audio is
10940 connected to the pad named "audio":
10942 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
10946 @c man end MULTIMEDIA SOURCES