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, 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 in output the top half of the video is mirrored
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 the 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", a filter with no
112 output pads is called a "sink".
114 @anchor{Filtergraph syntax}
115 @section Filtergraph syntax
117 A filtergraph can be represented using 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()} function 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 the following 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 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 Follows a BNF description for 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 (eventually 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 Some filter arguments require the use of special characters, typically
221 @code{:} to separate key=value pairs in a named options list. In this
222 case the user should perform a first level escaping when specifying
223 the filter arguments. For example, consider the following literal
224 string to be embedded in the @ref{drawtext} filter arguments:
226 this is a 'string': may contain one, or more, special characters
229 Since @code{:} is special for the filter arguments syntax, it needs to
230 be escaped, so you get:
232 text=this is a \'string\'\: may contain one, or more, special characters
235 A second level of escaping is required when embedding the filter
236 arguments in a filtergraph description, in order to escape all the
237 filtergraph special characters. Thus the example above becomes:
239 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
242 Finally an additional level of escaping may be needed when writing the
243 filtergraph description in a shell command, which depends on the
244 escaping rules of the adopted shell. For example, assuming that
245 @code{\} is special and needs to be escaped with another @code{\}, the
246 previous string will finally result in:
248 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
251 Sometimes, it might be more convenient to employ quoting in place of
252 escaping. For example the string:
254 Caesar: tu quoque, Brute, fili mi
257 Can be quoted in the filter arguments as:
259 text='Caesar: tu quoque, Brute, fili mi'
262 And finally inserted in a filtergraph like:
264 drawtext=text=\'Caesar: tu quoque\, Brute\, fili mi\'
267 See the ``Quoting and escaping'' section in the ffmpeg-utils manual
268 for more information about the escaping and quoting rules adopted by
271 @chapter Timeline editing
273 Some filters support a generic @option{enable} option. For the filters
274 supporting timeline editing, this option can be set to an expression which is
275 evaluated before sending a frame to the filter. If the evaluation is non-zero,
276 the filter will be enabled, otherwise the frame will be sent unchanged to the
277 next filter in the filtergraph.
279 The expression accepts the following values:
282 timestamp expressed in seconds, NAN if the input timestamp is unknown
285 sequential number of the input frame, starting from 0
288 the position in the file of the input frame, NAN if unknown
291 Additionally, these filters support an @option{enable} command that can be used
292 to re-define the expression.
294 Like any other filtering option, the @option{enable} option follows the same
297 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
298 minutes, and a @ref{curves} filter starting at 3 seconds:
300 smartblur = enable='between(t,10,3*60)',
301 curves = enable='gte(t,3)' : preset=cross_process
304 @c man end FILTERGRAPH DESCRIPTION
306 @chapter Audio Filters
307 @c man begin AUDIO FILTERS
309 When you configure your FFmpeg build, you can disable any of the
310 existing filters using @code{--disable-filters}.
311 The configure output will show the audio filters included in your
314 Below is a description of the currently available audio filters.
318 Convert the input audio format to the specified formats.
320 @emph{This filter is deprecated. Use @ref{aformat} instead.}
322 The filter accepts a string of the form:
323 "@var{sample_format}:@var{channel_layout}".
325 @var{sample_format} specifies the sample format, and can be a string or the
326 corresponding numeric value defined in @file{libavutil/samplefmt.h}. Use 'p'
327 suffix for a planar sample format.
329 @var{channel_layout} specifies the channel layout, and can be a string
330 or the corresponding number value defined in @file{libavutil/channel_layout.h}.
332 The special parameter "auto", signifies that the filter will
333 automatically select the output format depending on the output filter.
339 Convert input to float, planar, stereo:
345 Convert input to unsigned 8-bit, automatically select out channel layout:
353 Delay one or more audio channels.
355 Samples in delayed channel are filled with silence.
357 The filter accepts the following option:
361 Set list of delays in milliseconds for each channel separated by '|'.
362 At least one delay greater than 0 should be provided.
363 Unused delays will be silently ignored. If number of given delays is
364 smaller than number of channels all remaining channels will not be delayed.
371 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
372 the second channel (and any other channels that may be present) unchanged.
380 Apply echoing to the input audio.
382 Echoes are reflected sound and can occur naturally amongst mountains
383 (and sometimes large buildings) when talking or shouting; digital echo
384 effects emulate this behaviour and are often used to help fill out the
385 sound of a single instrument or vocal. The time difference between the
386 original signal and the reflection is the @code{delay}, and the
387 loudness of the reflected signal is the @code{decay}.
388 Multiple echoes can have different delays and decays.
390 A description of the accepted parameters follows.
394 Set input gain of reflected signal. Default is @code{0.6}.
397 Set output gain of reflected signal. Default is @code{0.3}.
400 Set list of time intervals in milliseconds between original signal and reflections
401 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
402 Default is @code{1000}.
405 Set list of loudnesses of reflected signals separated by '|'.
406 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
407 Default is @code{0.5}.
414 Make it sound as if there are twice as many instruments as are actually playing:
416 aecho=0.8:0.88:60:0.4
420 If delay is very short, then it sound like a (metallic) robot playing music:
426 A longer delay will sound like an open air concert in the mountains:
428 aecho=0.8:0.9:1000:0.3
432 Same as above but with one more mountain:
434 aecho=0.8:0.9:1000|1800:0.3|0.25
440 Modify an audio signal according to the specified expressions.
442 This filter accepts one or more expressions (one for each channel),
443 which are evaluated and used to modify a corresponding audio signal.
445 This filter accepts the following options:
449 Set the '|'-separated expressions list for each separate channel. If
450 the number of input channels is greater than the number of
451 expressions, the last specified expression is used for the remaining
454 @item channel_layout, c
455 Set output channel layout. If not specified, the channel layout is
456 specified by the number of expressions. If set to @samp{same}, it will
457 use by default the same input channel layout.
460 Each expression in @var{exprs} can contain the following constants and functions:
464 channel number of the current expression
467 number of the evaluated sample, starting from 0
473 time of the evaluated sample expressed in seconds
476 @item nb_out_channels
477 input and output number of channels
480 the value of input channel with number @var{CH}
483 Note: this filter is slow. For faster processing you should use a
492 aeval=val(ch)/2:c=same
496 Invert phase of the second channel:
504 Apply fade-in/out effect to input audio.
506 A description of the accepted parameters follows.
510 Specify the effect type, can be either @code{in} for fade-in, or
511 @code{out} for a fade-out effect. Default is @code{in}.
513 @item start_sample, ss
514 Specify the number of the start sample for starting to apply the fade
515 effect. Default is 0.
518 Specify the number of samples for which the fade effect has to last. At
519 the end of the fade-in effect the output audio will have the same
520 volume as the input audio, at the end of the fade-out transition
521 the output audio will be silence. Default is 44100.
524 Specify time for starting to apply the fade effect. Default is 0.
525 The accepted syntax is:
527 [-]HH[:MM[:SS[.m...]]]
530 See also the function @code{av_parse_time()}.
531 If set this option is used instead of @var{start_sample} one.
534 Specify the duration for which the fade effect has to last. Default is 0.
535 The accepted syntax is:
537 [-]HH[:MM[:SS[.m...]]]
540 See also the function @code{av_parse_time()}.
541 At the end of the fade-in effect the output audio will have the same
542 volume as the input audio, at the end of the fade-out transition
543 the output audio will be silence.
544 If set this option is used instead of @var{nb_samples} one.
547 Set curve for fade transition.
549 It accepts the following values:
552 select triangular, linear slope (default)
554 select quarter of sine wave
556 select half of sine wave
558 select exponential sine wave
562 select inverted parabola
578 Fade in first 15 seconds of audio:
584 Fade out last 25 seconds of a 900 seconds audio:
586 afade=t=out:st=875:d=25
593 Set output format constraints for the input audio. The framework will
594 negotiate the most appropriate format to minimize conversions.
596 The filter accepts the following named parameters:
600 A '|'-separated list of requested sample formats.
603 A '|'-separated list of requested sample rates.
605 @item channel_layouts
606 A '|'-separated list of requested channel layouts.
608 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
609 for the required syntax.
612 If a parameter is omitted, all values are allowed.
614 For example to force the output to either unsigned 8-bit or signed 16-bit stereo:
616 aformat=sample_fmts=u8|s16:channel_layouts=stereo
621 Apply a two-pole all-pass filter with central frequency (in Hz)
622 @var{frequency}, and filter-width @var{width}.
623 An all-pass filter changes the audio's frequency to phase relationship
624 without changing its frequency to amplitude relationship.
626 The filter accepts the following options:
633 Set method to specify band-width of filter.
646 Specify the band-width of a filter in width_type units.
651 Merge two or more audio streams into a single multi-channel stream.
653 The filter accepts the following options:
658 Set the number of inputs. Default is 2.
662 If the channel layouts of the inputs are disjoint, and therefore compatible,
663 the channel layout of the output will be set accordingly and the channels
664 will be reordered as necessary. If the channel layouts of the inputs are not
665 disjoint, the output will have all the channels of the first input then all
666 the channels of the second input, in that order, and the channel layout of
667 the output will be the default value corresponding to the total number of
670 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
671 is FC+BL+BR, then the output will be in 5.1, with the channels in the
672 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
673 first input, b1 is the first channel of the second input).
675 On the other hand, if both input are in stereo, the output channels will be
676 in the default order: a1, a2, b1, b2, and the channel layout will be
677 arbitrarily set to 4.0, which may or may not be the expected value.
679 All inputs must have the same sample rate, and format.
681 If inputs do not have the same duration, the output will stop with the
688 Merge two mono files into a stereo stream:
690 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
694 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
696 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
702 Mixes multiple audio inputs into a single output.
706 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
708 will mix 3 input audio streams to a single output with the same duration as the
709 first input and a dropout transition time of 3 seconds.
711 The filter accepts the following named parameters:
715 Number of inputs. If unspecified, it defaults to 2.
718 How to determine the end-of-stream.
722 Duration of longest input. (default)
725 Duration of shortest input.
728 Duration of first input.
732 @item dropout_transition
733 Transition time, in seconds, for volume renormalization when an input
734 stream ends. The default value is 2 seconds.
740 Pass the audio source unchanged to the output.
744 Pad the end of a audio stream with silence, this can be used together with
745 -shortest to extend audio streams to the same length as the video stream.
748 Add a phasing effect to the input audio.
750 A phaser filter creates series of peaks and troughs in the frequency spectrum.
751 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
753 A description of the accepted parameters follows.
757 Set input gain. Default is 0.4.
760 Set output gain. Default is 0.74
763 Set delay in milliseconds. Default is 3.0.
766 Set decay. Default is 0.4.
769 Set modulation speed in Hz. Default is 0.5.
772 Set modulation type. Default is triangular.
774 It accepts the following values:
784 Resample the input audio to the specified parameters, using the
785 libswresample library. If none are specified then the filter will
786 automatically convert between its input and output.
788 This filter is also able to stretch/squeeze the audio data to make it match
789 the timestamps or to inject silence / cut out audio to make it match the
790 timestamps, do a combination of both or do neither.
792 The filter accepts the syntax
793 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
794 expresses a sample rate and @var{resampler_options} is a list of
795 @var{key}=@var{value} pairs, separated by ":". See the
796 ffmpeg-resampler manual for the complete list of supported options.
802 Resample the input audio to 44100Hz:
808 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
809 samples per second compensation:
815 @section asetnsamples
817 Set the number of samples per each output audio frame.
819 The last output packet may contain a different number of samples, as
820 the filter will flush all the remaining samples when the input audio
823 The filter accepts the following options:
827 @item nb_out_samples, n
828 Set the number of frames per each output audio frame. The number is
829 intended as the number of samples @emph{per each channel}.
830 Default value is 1024.
833 If set to 1, the filter will pad the last audio frame with zeroes, so
834 that the last frame will contain the same number of samples as the
835 previous ones. Default value is 1.
838 For example, to set the number of per-frame samples to 1234 and
839 disable padding for the last frame, use:
841 asetnsamples=n=1234:p=0
846 Set the sample rate without altering the PCM data.
847 This will result in a change of speed and pitch.
849 The filter accepts the following options:
853 Set the output sample rate. Default is 44100 Hz.
858 Show a line containing various information for each input audio frame.
859 The input audio is not modified.
861 The shown line contains a sequence of key/value pairs of the form
862 @var{key}:@var{value}.
864 A description of each shown parameter follows:
868 sequential number of the input frame, starting from 0
871 Presentation timestamp of the input frame, in time base units; the time base
872 depends on the filter input pad, and is usually 1/@var{sample_rate}.
875 presentation timestamp of the input frame in seconds
878 position of the frame in the input stream, -1 if this information in
879 unavailable and/or meaningless (for example in case of synthetic audio)
888 sample rate for the audio frame
891 number of samples (per channel) in the frame
894 Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio
895 the data is treated as if all the planes were concatenated.
897 @item plane_checksums
898 A list of Adler-32 checksums for each data plane.
903 Display time domain statistical information about the audio channels.
904 Statistics are calculated and displayed for each audio channel and,
905 where applicable, an overall figure is also given.
907 The filter accepts the following option:
910 Short window length in seconds, used for peak and trough RMS measurement.
911 Default is @code{0.05} (50 miliseconds). Allowed range is @code{[0.1 - 10]}.
914 A description of each shown parameter follows:
918 Mean amplitude displacement from zero.
921 Minimal sample level.
924 Maximal sample level.
928 Standard peak and RMS level measured in dBFS.
932 Peak and trough values for RMS level measured over a short window.
935 Standard ratio of peak to RMS level (note: not in dB).
938 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
939 (i.e. either @var{Min level} or @var{Max level}).
942 Number of occasions (not the number of samples) that the signal attained either
943 @var{Min level} or @var{Max level}.
948 Forward two audio streams and control the order the buffers are forwarded.
950 The filter accepts the following options:
954 Set the expression deciding which stream should be
955 forwarded next: if the result is negative, the first stream is forwarded; if
956 the result is positive or zero, the second stream is forwarded. It can use
957 the following variables:
961 number of buffers forwarded so far on each stream
963 number of samples forwarded so far on each stream
965 current timestamp of each stream
968 The default value is @code{t1-t2}, which means to always forward the stream
969 that has a smaller timestamp.
974 Stress-test @code{amerge} by randomly sending buffers on the wrong
975 input, while avoiding too much of a desynchronization:
977 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
978 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
984 Synchronize audio data with timestamps by squeezing/stretching it and/or
985 dropping samples/adding silence when needed.
987 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
989 The filter accepts the following named parameters:
993 Enable stretching/squeezing the data to make it match the timestamps. Disabled
994 by default. When disabled, time gaps are covered with silence.
997 Minimum difference between timestamps and audio data (in seconds) to trigger
998 adding/dropping samples. Default value is 0.1. If you get non-perfect sync with
999 this filter, try setting this parameter to 0.
1002 Maximum compensation in samples per second. Relevant only with compensate=1.
1006 Assume the first pts should be this value. The time base is 1 / sample rate.
1007 This allows for padding/trimming at the start of stream. By default, no
1008 assumption is made about the first frame's expected pts, so no padding or
1009 trimming is done. For example, this could be set to 0 to pad the beginning with
1010 silence if an audio stream starts after the video stream or to trim any samples
1011 with a negative pts due to encoder delay.
1019 The filter accepts exactly one parameter, the audio tempo. If not
1020 specified then the filter will assume nominal 1.0 tempo. Tempo must
1021 be in the [0.5, 2.0] range.
1023 @subsection Examples
1027 Slow down audio to 80% tempo:
1033 To speed up audio to 125% tempo:
1041 Trim the input so that the output contains one continuous subpart of the input.
1043 This filter accepts the following options:
1046 Specify time of the start of the kept section, i.e. the audio sample
1047 with the timestamp @var{start} will be the first sample in the output.
1050 Specify time of the first audio sample that will be dropped, i.e. the
1051 audio sample immediately preceding the one with the timestamp @var{end} will be
1052 the last sample in the output.
1055 Same as @var{start}, except this option sets the start timestamp in samples
1059 Same as @var{end}, except this option sets the end timestamp in samples instead
1063 Specify maximum duration of the output.
1066 Number of the first sample that should be passed to output.
1069 Number of the first sample that should be dropped.
1072 @option{start}, @option{end}, @option{duration} are expressed as time
1073 duration specifications, check the "Time duration" section in the
1074 ffmpeg-utils manual.
1076 Note that the first two sets of the start/end options and the @option{duration}
1077 option look at the frame timestamp, while the _sample options simply count the
1078 samples that pass through the filter. So start/end_pts and start/end_sample will
1079 give different results when the timestamps are wrong, inexact or do not start at
1080 zero. Also note that this filter does not modify the timestamps. If you wish
1081 that the output timestamps start at zero, insert the asetpts filter after the
1084 If multiple start or end options are set, this filter tries to be greedy and
1085 keep all samples that match at least one of the specified constraints. To keep
1086 only the part that matches all the constraints at once, chain multiple atrim
1089 The defaults are such that all the input is kept. So it is possible to set e.g.
1090 just the end values to keep everything before the specified time.
1095 drop everything except the second minute of input
1097 ffmpeg -i INPUT -af atrim=60:120
1101 keep only the first 1000 samples
1103 ffmpeg -i INPUT -af atrim=end_sample=1000
1110 Apply a two-pole Butterworth band-pass filter with central
1111 frequency @var{frequency}, and (3dB-point) band-width width.
1112 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1113 instead of the default: constant 0dB peak gain.
1114 The filter roll off at 6dB per octave (20dB per decade).
1116 The filter accepts the following options:
1120 Set the filter's central frequency. Default is @code{3000}.
1123 Constant skirt gain if set to 1. Defaults to 0.
1126 Set method to specify band-width of filter.
1139 Specify the band-width of a filter in width_type units.
1144 Apply a two-pole Butterworth band-reject filter with central
1145 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1146 The filter roll off at 6dB per octave (20dB per decade).
1148 The filter accepts the following options:
1152 Set the filter's central frequency. Default is @code{3000}.
1155 Set method to specify band-width of filter.
1168 Specify the band-width of a filter in width_type units.
1173 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1174 shelving filter with a response similar to that of a standard
1175 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1177 The filter accepts the following options:
1181 Give the gain at 0 Hz. Its useful range is about -20
1182 (for a large cut) to +20 (for a large boost).
1183 Beware of clipping when using a positive gain.
1186 Set the filter's central frequency and so can be used
1187 to extend or reduce the frequency range to be boosted or cut.
1188 The default value is @code{100} Hz.
1191 Set method to specify band-width of filter.
1204 Determine how steep is the filter's shelf transition.
1209 Apply a biquad IIR filter with the given coefficients.
1210 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1211 are the numerator and denominator coefficients respectively.
1215 Remap input channels to new locations.
1217 This filter accepts the following named parameters:
1219 @item channel_layout
1220 Channel layout of the output stream.
1223 Map channels from input to output. The argument is a '|'-separated list of
1224 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1225 @var{in_channel} form. @var{in_channel} can be either the name of the input
1226 channel (e.g. FL for front left) or its index in the input channel layout.
1227 @var{out_channel} is the name of the output channel or its index in the output
1228 channel layout. If @var{out_channel} is not given then it is implicitly an
1229 index, starting with zero and increasing by one for each mapping.
1232 If no mapping is present, the filter will implicitly map input channels to
1233 output channels preserving index.
1235 For example, assuming a 5.1+downmix input MOV file
1237 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1239 will create an output WAV file tagged as stereo from the downmix channels of
1242 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1244 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1247 @section channelsplit
1249 Split each channel in input audio stream into a separate output stream.
1251 This filter accepts the following named parameters:
1253 @item channel_layout
1254 Channel layout of the input stream. Default is "stereo".
1257 For example, assuming a stereo input MP3 file
1259 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1261 will create an output Matroska file with two audio streams, one containing only
1262 the left channel and the other the right channel.
1264 To split a 5.1 WAV file into per-channel files
1266 ffmpeg -i in.wav -filter_complex
1267 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1268 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1269 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1275 Compress or expand audio dynamic range.
1277 A description of the accepted options follows.
1282 Set list of times in seconds for each channel over which the instantaneous
1283 level of the input signal is averaged to determine its volume.
1284 @option{attacks} refers to increase of volume and @option{decays} refers
1285 to decrease of volume.
1286 For most situations, the attack time (response to the audio getting louder)
1287 should be shorter than the decay time because the human ear is more sensitive
1288 to sudden loud audio than sudden soft audio.
1289 Typical value for attack is @code{0.3} seconds and for decay @code{0.8}
1293 Set list of points for transfer function, specified in dB relative to maximum
1294 possible signal amplitude.
1295 Each key points list need to be defined using the following syntax:
1296 @code{x0/y0 x1/y1 x2/y2 ...}.
1298 The input values must be in strictly increasing order but the transfer
1299 function does not have to be monotonically rising.
1300 The point @code{0/0} is assumed but may be overridden (by @code{0/out-dBn}).
1301 Typical values for the transfer function are @code{-70/-70 -60/-20}.
1304 Set amount for which the points at where adjacent line segments on the
1305 transfer function meet will be rounded. Defaults is @code{0.01}.
1308 Set additional gain in dB to be applied at all points on the transfer function
1309 and allows easy adjustment of the overall gain.
1310 Default is @code{0}.
1313 Set initial volume in dB to be assumed for each channel when filtering starts.
1314 This permits the user to supply a nominal level initially, so that,
1315 for example, a very large gain is not applied to initial signal levels before
1316 the companding has begun to operate. A typical value for audio which is
1317 initially quiet is -90 dB. Default is @code{0}.
1320 Set delay in seconds. Default is @code{0}. The input audio
1321 is analysed immediately, but audio is delayed before being fed to the
1322 volume adjuster. Specifying a delay approximately equal to the attack/decay
1323 times allows the filter to effectively operate in predictive rather than
1327 @subsection Examples
1330 Make music with both quiet and loud passages suitable for listening
1331 in a noisy environment:
1333 compand=.3 .3:1 1:-90/-60 -60/-40 -40/-30 -20/-20:6:0:-90:0.2
1337 Noise-gate for when the noise is at a lower level than the signal:
1339 compand=.1 .1:.2 .2:-900/-900 -50.1/-900 -50/-50:.01:0:-90:.1
1343 Here is another noise-gate, this time for when the noise is at a higher level
1344 than the signal (making it, in some ways, similar to squelch):
1346 compand=.1 .1:.1 .1:-45.1/-45.1 -45/-900 0/-900:.01:45:-90:.1
1352 Make audio easier to listen to on headphones.
1354 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1355 so that when listened to on headphones the stereo image is moved from
1356 inside your head (standard for headphones) to outside and in front of
1357 the listener (standard for speakers).
1363 Apply a two-pole peaking equalisation (EQ) filter. With this
1364 filter, the signal-level at and around a selected frequency can
1365 be increased or decreased, whilst (unlike bandpass and bandreject
1366 filters) that at all other frequencies is unchanged.
1368 In order to produce complex equalisation curves, this filter can
1369 be given several times, each with a different central frequency.
1371 The filter accepts the following options:
1375 Set the filter's central frequency in Hz.
1378 Set method to specify band-width of filter.
1391 Specify the band-width of a filter in width_type units.
1394 Set the required gain or attenuation in dB.
1395 Beware of clipping when using a positive gain.
1400 Apply a high-pass filter with 3dB point frequency.
1401 The filter can be either single-pole, or double-pole (the default).
1402 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1404 The filter accepts the following options:
1408 Set frequency in Hz. Default is 3000.
1411 Set number of poles. Default is 2.
1414 Set method to specify band-width of filter.
1427 Specify the band-width of a filter in width_type units.
1428 Applies only to double-pole filter.
1429 The default is 0.707q and gives a Butterworth response.
1434 Join multiple input streams into one multi-channel stream.
1436 The filter accepts the following named parameters:
1440 Number of input streams. Defaults to 2.
1442 @item channel_layout
1443 Desired output channel layout. Defaults to stereo.
1446 Map channels from inputs to output. The argument is a '|'-separated list of
1447 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1448 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1449 can be either the name of the input channel (e.g. FL for front left) or its
1450 index in the specified input stream. @var{out_channel} is the name of the output
1454 The filter will attempt to guess the mappings when those are not specified
1455 explicitly. It does so by first trying to find an unused matching input channel
1456 and if that fails it picks the first unused input channel.
1458 E.g. to join 3 inputs (with properly set channel layouts)
1460 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1463 To build a 5.1 output from 6 single-channel streams:
1465 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1466 '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'
1472 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1474 To enable compilation of this filter you need to configure FFmpeg with
1475 @code{--enable-ladspa}.
1479 Specifies the name of LADSPA plugin library to load. If the environment
1480 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1481 each one of the directories specified by the colon separated list in
1482 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1483 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1484 @file{/usr/lib/ladspa/}.
1487 Specifies the plugin within the library. Some libraries contain only
1488 one plugin, but others contain many of them. If this is not set filter
1489 will list all available plugins within the specified library.
1492 Set the '|' separated list of controls which are zero or more floating point
1493 values that determine the behavior of the loaded plugin (for example delay,
1495 Controls need to be defined using the following syntax:
1496 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1497 @var{valuei} is the value set on the @var{i}-th control.
1498 If @option{controls} is set to @code{help}, all available controls and
1499 their valid ranges are printed.
1501 @item sample_rate, s
1502 Specify the sample rate, default to 44100. Only used if plugin have
1506 Set the number of samples per channel per each output frame, default
1507 is 1024. Only used if plugin have zero inputs.
1510 Set the minimum duration of the sourced audio. See the function
1511 @code{av_parse_time()} for the accepted format, also check the "Time duration"
1512 section in the ffmpeg-utils manual.
1513 Note that the resulting duration may be greater than the specified duration,
1514 as the generated audio is always cut at the end of a complete frame.
1515 If not specified, or the expressed duration is negative, the audio is
1516 supposed to be generated forever.
1517 Only used if plugin have zero inputs.
1521 @subsection Examples
1525 List all available plugins within amp (LADSPA example plugin) library:
1531 List all available controls and their valid ranges for @code{vcf_notch}
1532 plugin from @code{VCF} library:
1534 ladspa=f=vcf:p=vcf_notch:c=help
1538 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1541 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1545 Add reverberation to the audio using TAP-plugins
1546 (Tom's Audio Processing plugins):
1548 ladspa=file=tap_reverb:tap_reverb
1552 Generate white noise, with 0.2 amplitude:
1554 ladspa=file=cmt:noise_source_white:c=c0=.2
1558 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1559 @code{C* Audio Plugin Suite} (CAPS) library:
1561 ladspa=file=caps:Click:c=c1=20'
1565 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1567 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1571 @subsection Commands
1573 This filter supports the following commands:
1576 Modify the @var{N}-th control value.
1578 If the specified value is not valid, it is ignored and prior one is kept.
1583 Apply a low-pass filter with 3dB point frequency.
1584 The filter can be either single-pole or double-pole (the default).
1585 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1587 The filter accepts the following options:
1591 Set frequency in Hz. Default is 500.
1594 Set number of poles. Default is 2.
1597 Set method to specify band-width of filter.
1610 Specify the band-width of a filter in width_type units.
1611 Applies only to double-pole filter.
1612 The default is 0.707q and gives a Butterworth response.
1617 Mix channels with specific gain levels. The filter accepts the output
1618 channel layout followed by a set of channels definitions.
1620 This filter is also designed to remap efficiently the channels of an audio
1623 The filter accepts parameters of the form:
1624 "@var{l}:@var{outdef}:@var{outdef}:..."
1628 output channel layout or number of channels
1631 output channel specification, of the form:
1632 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1635 output channel to define, either a channel name (FL, FR, etc.) or a channel
1636 number (c0, c1, etc.)
1639 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1642 input channel to use, see out_name for details; it is not possible to mix
1643 named and numbered input channels
1646 If the `=' in a channel specification is replaced by `<', then the gains for
1647 that specification will be renormalized so that the total is 1, thus
1648 avoiding clipping noise.
1650 @subsection Mixing examples
1652 For example, if you want to down-mix from stereo to mono, but with a bigger
1653 factor for the left channel:
1655 pan=1:c0=0.9*c0+0.1*c1
1658 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1659 7-channels surround:
1661 pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1664 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1665 that should be preferred (see "-ac" option) unless you have very specific
1668 @subsection Remapping examples
1670 The channel remapping will be effective if, and only if:
1673 @item gain coefficients are zeroes or ones,
1674 @item only one input per channel output,
1677 If all these conditions are satisfied, the filter will notify the user ("Pure
1678 channel mapping detected"), and use an optimized and lossless method to do the
1681 For example, if you have a 5.1 source and want a stereo audio stream by
1682 dropping the extra channels:
1684 pan="stereo: c0=FL : c1=FR"
1687 Given the same source, you can also switch front left and front right channels
1688 and keep the input channel layout:
1690 pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
1693 If the input is a stereo audio stream, you can mute the front left channel (and
1694 still keep the stereo channel layout) with:
1699 Still with a stereo audio stream input, you can copy the right channel in both
1700 front left and right:
1702 pan="stereo: c0=FR : c1=FR"
1707 ReplayGain scanner filter. This filter takes an audio stream as an input and
1708 outputs it unchanged.
1709 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1713 Convert the audio sample format, sample rate and channel layout. This filter is
1714 not meant to be used directly.
1716 @section silencedetect
1718 Detect silence in an audio stream.
1720 This filter logs a message when it detects that the input audio volume is less
1721 or equal to a noise tolerance value for a duration greater or equal to the
1722 minimum detected noise duration.
1724 The printed times and duration are expressed in seconds.
1726 The filter accepts the following options:
1730 Set silence duration until notification (default is 2 seconds).
1733 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1734 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1737 @subsection Examples
1741 Detect 5 seconds of silence with -50dB noise tolerance:
1743 silencedetect=n=-50dB:d=5
1747 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1748 tolerance in @file{silence.mp3}:
1750 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1756 Boost or cut treble (upper) frequencies of the audio using a two-pole
1757 shelving filter with a response similar to that of a standard
1758 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1760 The filter accepts the following options:
1764 Give the gain at whichever is the lower of ~22 kHz and the
1765 Nyquist frequency. Its useful range is about -20 (for a large cut)
1766 to +20 (for a large boost). Beware of clipping when using a positive gain.
1769 Set the filter's central frequency and so can be used
1770 to extend or reduce the frequency range to be boosted or cut.
1771 The default value is @code{3000} Hz.
1774 Set method to specify band-width of filter.
1787 Determine how steep is the filter's shelf transition.
1792 Adjust the input audio volume.
1794 The filter accepts the following options:
1799 Expresses how the audio volume will be increased or decreased.
1801 Output values are clipped to the maximum value.
1803 The output audio volume is given by the relation:
1805 @var{output_volume} = @var{volume} * @var{input_volume}
1808 Default value for @var{volume} is 1.0.
1811 Set the mathematical precision.
1813 This determines which input sample formats will be allowed, which affects the
1814 precision of the volume scaling.
1818 8-bit fixed-point; limits input sample format to U8, S16, and S32.
1820 32-bit floating-point; limits input sample format to FLT. (default)
1822 64-bit floating-point; limits input sample format to DBL.
1826 @subsection Examples
1830 Halve the input audio volume:
1834 volume=volume=-6.0206dB
1837 In all the above example the named key for @option{volume} can be
1838 omitted, for example like in:
1844 Increase input audio power by 6 decibels using fixed-point precision:
1846 volume=volume=6dB:precision=fixed
1850 @section volumedetect
1852 Detect the volume of the input video.
1854 The filter has no parameters. The input is not modified. Statistics about
1855 the volume will be printed in the log when the input stream end is reached.
1857 In particular it will show the mean volume (root mean square), maximum
1858 volume (on a per-sample basis), and the beginning of a histogram of the
1859 registered volume values (from the maximum value to a cumulated 1/1000 of
1862 All volumes are in decibels relative to the maximum PCM value.
1864 @subsection Examples
1866 Here is an excerpt of the output:
1868 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
1869 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
1870 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
1871 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
1872 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
1873 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
1874 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
1875 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
1876 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
1882 The mean square energy is approximately -27 dB, or 10^-2.7.
1884 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
1886 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
1889 In other words, raising the volume by +4 dB does not cause any clipping,
1890 raising it by +5 dB causes clipping for 6 samples, etc.
1892 @c man end AUDIO FILTERS
1894 @chapter Audio Sources
1895 @c man begin AUDIO SOURCES
1897 Below is a description of the currently available audio sources.
1901 Buffer audio frames, and make them available to the filter chain.
1903 This source is mainly intended for a programmatic use, in particular
1904 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
1906 It accepts the following named parameters:
1911 Timebase which will be used for timestamps of submitted frames. It must be
1912 either a floating-point number or in @var{numerator}/@var{denominator} form.
1915 The sample rate of the incoming audio buffers.
1918 The sample format of the incoming audio buffers.
1919 Either a sample format name or its corresponging integer representation from
1920 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
1922 @item channel_layout
1923 The channel layout of the incoming audio buffers.
1924 Either a channel layout name from channel_layout_map in
1925 @file{libavutil/channel_layout.c} or its corresponding integer representation
1926 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
1929 The number of channels of the incoming audio buffers.
1930 If both @var{channels} and @var{channel_layout} are specified, then they
1935 @subsection Examples
1938 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
1941 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
1942 Since the sample format with name "s16p" corresponds to the number
1943 6 and the "stereo" channel layout corresponds to the value 0x3, this is
1946 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
1951 Generate an audio signal specified by an expression.
1953 This source accepts in input one or more expressions (one for each
1954 channel), which are evaluated and used to generate a corresponding
1957 This source accepts the following options:
1961 Set the '|'-separated expressions list for each separate channel. In case the
1962 @option{channel_layout} option is not specified, the selected channel layout
1963 depends on the number of provided expressions. Otherwise the last
1964 specified expression is applied to the remaining output channels.
1966 @item channel_layout, c
1967 Set the channel layout. The number of channels in the specified layout
1968 must be equal to the number of specified expressions.
1971 Set the minimum duration of the sourced audio. See the function
1972 @code{av_parse_time()} for the accepted format.
1973 Note that the resulting duration may be greater than the specified
1974 duration, as the generated audio is always cut at the end of a
1977 If not specified, or the expressed duration is negative, the audio is
1978 supposed to be generated forever.
1981 Set the number of samples per channel per each output frame,
1984 @item sample_rate, s
1985 Specify the sample rate, default to 44100.
1988 Each expression in @var{exprs} can contain the following constants:
1992 number of the evaluated sample, starting from 0
1995 time of the evaluated sample expressed in seconds, starting from 0
2002 @subsection Examples
2012 Generate a sin signal with frequency of 440 Hz, set sample rate to
2015 aevalsrc="sin(440*2*PI*t):s=8000"
2019 Generate a two channels signal, specify the channel layout (Front
2020 Center + Back Center) explicitly:
2022 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2026 Generate white noise:
2028 aevalsrc="-2+random(0)"
2032 Generate an amplitude modulated signal:
2034 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2038 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2040 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2047 Null audio source, return unprocessed audio frames. It is mainly useful
2048 as a template and to be employed in analysis / debugging tools, or as
2049 the source for filters which ignore the input data (for example the sox
2052 This source accepts the following options:
2056 @item channel_layout, cl
2058 Specify the channel layout, and can be either an integer or a string
2059 representing a channel layout. The default value of @var{channel_layout}
2062 Check the channel_layout_map definition in
2063 @file{libavutil/channel_layout.c} for the mapping between strings and
2064 channel layout values.
2066 @item sample_rate, r
2067 Specify the sample rate, and defaults to 44100.
2070 Set the number of samples per requested frames.
2074 @subsection Examples
2078 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2080 anullsrc=r=48000:cl=4
2084 Do the same operation with a more obvious syntax:
2086 anullsrc=r=48000:cl=mono
2090 All the parameters need to be explicitly defined.
2094 Synthesize a voice utterance using the libflite library.
2096 To enable compilation of this filter you need to configure FFmpeg with
2097 @code{--enable-libflite}.
2099 Note that the flite library is not thread-safe.
2101 The filter accepts the following options:
2106 If set to 1, list the names of the available voices and exit
2107 immediately. Default value is 0.
2110 Set the maximum number of samples per frame. Default value is 512.
2113 Set the filename containing the text to speak.
2116 Set the text to speak.
2119 Set the voice to use for the speech synthesis. Default value is
2120 @code{kal}. See also the @var{list_voices} option.
2123 @subsection Examples
2127 Read from file @file{speech.txt}, and synthetize the text using the
2128 standard flite voice:
2130 flite=textfile=speech.txt
2134 Read the specified text selecting the @code{slt} voice:
2136 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2140 Input text to ffmpeg:
2142 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2146 Make @file{ffplay} speak the specified text, using @code{flite} and
2147 the @code{lavfi} device:
2149 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2153 For more information about libflite, check:
2154 @url{http://www.speech.cs.cmu.edu/flite/}
2158 Generate an audio signal made of a sine wave with amplitude 1/8.
2160 The audio signal is bit-exact.
2162 The filter accepts the following options:
2167 Set the carrier frequency. Default is 440 Hz.
2169 @item beep_factor, b
2170 Enable a periodic beep every second with frequency @var{beep_factor} times
2171 the carrier frequency. Default is 0, meaning the beep is disabled.
2173 @item sample_rate, r
2174 Specify the sample rate, default is 44100.
2177 Specify the duration of the generated audio stream.
2179 @item samples_per_frame
2180 Set the number of samples per output frame, default is 1024.
2183 @subsection Examples
2188 Generate a simple 440 Hz sine wave:
2194 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2198 sine=frequency=220:beep_factor=4:duration=5
2203 @c man end AUDIO SOURCES
2205 @chapter Audio Sinks
2206 @c man begin AUDIO SINKS
2208 Below is a description of the currently available audio sinks.
2210 @section abuffersink
2212 Buffer audio frames, and make them available to the end of filter chain.
2214 This sink is mainly intended for programmatic use, in particular
2215 through the interface defined in @file{libavfilter/buffersink.h}
2216 or the options system.
2218 It accepts a pointer to an AVABufferSinkContext structure, which
2219 defines the incoming buffers' formats, to be passed as the opaque
2220 parameter to @code{avfilter_init_filter} for initialization.
2224 Null audio sink, do absolutely nothing with the input audio. It is
2225 mainly useful as a template and to be employed in analysis / debugging
2228 @c man end AUDIO SINKS
2230 @chapter Video Filters
2231 @c man begin VIDEO FILTERS
2233 When you configure your FFmpeg build, you can disable any of the
2234 existing filters using @code{--disable-filters}.
2235 The configure output will show the video filters included in your
2238 Below is a description of the currently available video filters.
2240 @section alphaextract
2242 Extract the alpha component from the input as a grayscale video. This
2243 is especially useful with the @var{alphamerge} filter.
2247 Add or replace the alpha component of the primary input with the
2248 grayscale value of a second input. This is intended for use with
2249 @var{alphaextract} to allow the transmission or storage of frame
2250 sequences that have alpha in a format that doesn't support an alpha
2253 For example, to reconstruct full frames from a normal YUV-encoded video
2254 and a separate video created with @var{alphaextract}, you might use:
2256 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2259 Since this filter is designed for reconstruction, it operates on frame
2260 sequences without considering timestamps, and terminates when either
2261 input reaches end of stream. This will cause problems if your encoding
2262 pipeline drops frames. If you're trying to apply an image as an
2263 overlay to a video stream, consider the @var{overlay} filter instead.
2267 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2268 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2269 Substation Alpha) subtitles files.
2273 Compute the bounding box for the non-black pixels in the input frame
2276 This filter computes the bounding box containing all the pixels with a
2277 luminance value greater than the minimum allowed value.
2278 The parameters describing the bounding box are printed on the filter
2281 The filter accepts the following option:
2285 Set the minimal luminance value. Default is @code{16}.
2288 @section blackdetect
2290 Detect video intervals that are (almost) completely black. Can be
2291 useful to detect chapter transitions, commercials, or invalid
2292 recordings. Output lines contains the time for the start, end and
2293 duration of the detected black interval expressed in seconds.
2295 In order to display the output lines, you need to set the loglevel at
2296 least to the AV_LOG_INFO value.
2298 The filter accepts the following options:
2301 @item black_min_duration, d
2302 Set the minimum detected black duration expressed in seconds. It must
2303 be a non-negative floating point number.
2305 Default value is 2.0.
2307 @item picture_black_ratio_th, pic_th
2308 Set the threshold for considering a picture "black".
2309 Express the minimum value for the ratio:
2311 @var{nb_black_pixels} / @var{nb_pixels}
2314 for which a picture is considered black.
2315 Default value is 0.98.
2317 @item pixel_black_th, pix_th
2318 Set the threshold for considering a pixel "black".
2320 The threshold expresses the maximum pixel luminance value for which a
2321 pixel is considered "black". The provided value is scaled according to
2322 the following equation:
2324 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2327 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2328 the input video format, the range is [0-255] for YUV full-range
2329 formats and [16-235] for YUV non full-range formats.
2331 Default value is 0.10.
2334 The following example sets the maximum pixel threshold to the minimum
2335 value, and detects only black intervals of 2 or more seconds:
2337 blackdetect=d=2:pix_th=0.00
2342 Detect frames that are (almost) completely black. Can be useful to
2343 detect chapter transitions or commercials. Output lines consist of
2344 the frame number of the detected frame, the percentage of blackness,
2345 the position in the file if known or -1 and the timestamp in seconds.
2347 In order to display the output lines, you need to set the loglevel at
2348 least to the AV_LOG_INFO value.
2350 The filter accepts the following options:
2355 Set the percentage of the pixels that have to be below the threshold, defaults
2358 @item threshold, thresh
2359 Set the threshold below which a pixel value is considered black, defaults to
2366 Blend two video frames into each other.
2368 It takes two input streams and outputs one stream, the first input is the
2369 "top" layer and second input is "bottom" layer.
2370 Output terminates when shortest input terminates.
2372 A description of the accepted options follows.
2380 Set blend mode for specific pixel component or all pixel components in case
2381 of @var{all_mode}. Default value is @code{normal}.
2383 Available values for component modes are:
2416 Set blend opacity for specific pixel component or all pixel components in case
2417 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2424 Set blend expression for specific pixel component or all pixel components in case
2425 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2427 The expressions can use the following variables:
2431 The sequential number of the filtered frame, starting from @code{0}.
2435 the coordinates of the current sample
2439 the width and height of currently filtered plane
2443 Width and height scale depending on the currently filtered plane. It is the
2444 ratio between the corresponding luma plane number of pixels and the current
2445 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2446 @code{0.5,0.5} for chroma planes.
2449 Time of the current frame, expressed in seconds.
2452 Value of pixel component at current location for first video frame (top layer).
2455 Value of pixel component at current location for second video frame (bottom layer).
2459 Force termination when the shortest input terminates. Default is @code{0}.
2461 Continue applying the last bottom frame after the end of the stream. A value of
2462 @code{0} disable the filter after the last frame of the bottom layer is reached.
2463 Default is @code{1}.
2466 @subsection Examples
2470 Apply transition from bottom layer to top layer in first 10 seconds:
2472 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2476 Apply 1x1 checkerboard effect:
2478 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2482 Apply uncover left effect:
2484 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2488 Apply uncover down effect:
2490 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2494 Apply uncover up-left effect:
2496 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2502 Apply boxblur algorithm to the input video.
2504 The filter accepts the following options:
2508 @item luma_radius, lr
2509 @item luma_power, lp
2510 @item chroma_radius, cr
2511 @item chroma_power, cp
2512 @item alpha_radius, ar
2513 @item alpha_power, ap
2517 A description of the accepted options follows.
2520 @item luma_radius, lr
2521 @item chroma_radius, cr
2522 @item alpha_radius, ar
2523 Set an expression for the box radius in pixels used for blurring the
2524 corresponding input plane.
2526 The radius value must be a non-negative number, and must not be
2527 greater than the value of the expression @code{min(w,h)/2} for the
2528 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2531 Default value for @option{luma_radius} is "2". If not specified,
2532 @option{chroma_radius} and @option{alpha_radius} default to the
2533 corresponding value set for @option{luma_radius}.
2535 The expressions can contain the following constants:
2539 the input width and height in pixels
2543 the input chroma image width and height in pixels
2547 horizontal and vertical chroma subsample values. For example for the
2548 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2551 @item luma_power, lp
2552 @item chroma_power, cp
2553 @item alpha_power, ap
2554 Specify how many times the boxblur filter is applied to the
2555 corresponding plane.
2557 Default value for @option{luma_power} is 2. If not specified,
2558 @option{chroma_power} and @option{alpha_power} default to the
2559 corresponding value set for @option{luma_power}.
2561 A value of 0 will disable the effect.
2564 @subsection Examples
2568 Apply a boxblur filter with luma, chroma, and alpha radius
2571 boxblur=luma_radius=2:luma_power=1
2576 Set luma radius to 2, alpha and chroma radius to 0:
2578 boxblur=2:1:cr=0:ar=0
2582 Set luma and chroma radius to a fraction of the video dimension:
2584 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2588 @section colorbalance
2589 Modify intensity of primary colors (red, green and blue) of input frames.
2591 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2592 regions for the red-cyan, green-magenta or blue-yellow balance.
2594 A positive adjustment value shifts the balance towards the primary color, a negative
2595 value towards the complementary color.
2597 The filter accepts the following options:
2603 Adjust red, green and blue shadows (darkest pixels).
2608 Adjust red, green and blue midtones (medium pixels).
2613 Adjust red, green and blue highlights (brightest pixels).
2615 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2618 @subsection Examples
2622 Add red color cast to shadows:
2628 @section colorchannelmixer
2630 Adjust video input frames by re-mixing color channels.
2632 This filter modifies a color channel by adding the values associated to
2633 the other channels of the same pixels. For example if the value to
2634 modify is red, the output value will be:
2636 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2639 The filter accepts the following options:
2646 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2647 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2653 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2654 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2660 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2661 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2667 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2668 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2670 Allowed ranges for options are @code{[-2.0, 2.0]}.
2673 @subsection Examples
2677 Convert source to grayscale:
2679 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2682 Simulate sepia tones:
2684 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
2688 @section colormatrix
2690 Convert color matrix.
2692 The filter accepts the following options:
2697 Specify the source and destination color matrix. Both values must be
2700 The accepted values are:
2716 For example to convert from BT.601 to SMPTE-240M, use the command:
2718 colormatrix=bt601:smpte240m
2723 Copy the input source unchanged to the output. Mainly useful for
2728 Crop the input video to given dimensions.
2730 The filter accepts the following options:
2734 Width of the output video. It defaults to @code{iw}.
2735 This expression is evaluated only once during the filter
2739 Height of the output video. It defaults to @code{ih}.
2740 This expression is evaluated only once during the filter
2744 Horizontal position, in the input video, of the left edge of the output video.
2745 It defaults to @code{(in_w-out_w)/2}.
2746 This expression is evaluated per-frame.
2749 Vertical position, in the input video, of the top edge of the output video.
2750 It defaults to @code{(in_h-out_h)/2}.
2751 This expression is evaluated per-frame.
2754 If set to 1 will force the output display aspect ratio
2755 to be the same of the input, by changing the output sample aspect
2756 ratio. It defaults to 0.
2759 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
2760 expressions containing the following constants:
2765 the computed values for @var{x} and @var{y}. They are evaluated for
2770 the input width and height
2774 same as @var{in_w} and @var{in_h}
2778 the output (cropped) width and height
2782 same as @var{out_w} and @var{out_h}
2785 same as @var{iw} / @var{ih}
2788 input sample aspect ratio
2791 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
2795 horizontal and vertical chroma subsample values. For example for the
2796 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2799 the number of input frame, starting from 0
2802 the position in the file of the input frame, NAN if unknown
2805 timestamp expressed in seconds, NAN if the input timestamp is unknown
2809 The expression for @var{out_w} may depend on the value of @var{out_h},
2810 and the expression for @var{out_h} may depend on @var{out_w}, but they
2811 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
2812 evaluated after @var{out_w} and @var{out_h}.
2814 The @var{x} and @var{y} parameters specify the expressions for the
2815 position of the top-left corner of the output (non-cropped) area. They
2816 are evaluated for each frame. If the evaluated value is not valid, it
2817 is approximated to the nearest valid value.
2819 The expression for @var{x} may depend on @var{y}, and the expression
2820 for @var{y} may depend on @var{x}.
2822 @subsection Examples
2826 Crop area with size 100x100 at position (12,34).
2831 Using named options, the example above becomes:
2833 crop=w=100:h=100:x=12:y=34
2837 Crop the central input area with size 100x100:
2843 Crop the central input area with size 2/3 of the input video:
2845 crop=2/3*in_w:2/3*in_h
2849 Crop the input video central square:
2856 Delimit the rectangle with the top-left corner placed at position
2857 100:100 and the right-bottom corner corresponding to the right-bottom
2858 corner of the input image:
2860 crop=in_w-100:in_h-100:100:100
2864 Crop 10 pixels from the left and right borders, and 20 pixels from
2865 the top and bottom borders
2867 crop=in_w-2*10:in_h-2*20
2871 Keep only the bottom right quarter of the input image:
2873 crop=in_w/2:in_h/2:in_w/2:in_h/2
2877 Crop height for getting Greek harmony:
2879 crop=in_w:1/PHI*in_w
2883 Appply trembling effect:
2885 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)
2889 Apply erratic camera effect depending on timestamp:
2891 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)"
2895 Set x depending on the value of y:
2897 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
2903 Auto-detect crop size.
2905 Calculate necessary cropping parameters and prints the recommended
2906 parameters through the logging system. The detected dimensions
2907 correspond to the non-black area of the input video.
2909 The filter accepts the following options:
2914 Set higher black value threshold, which can be optionally specified
2915 from nothing (0) to everything (255). An intensity value greater
2916 to the set value is considered non-black. Default value is 24.
2919 Set the value for which the width/height should be divisible by. The
2920 offset is automatically adjusted to center the video. Use 2 to get
2921 only even dimensions (needed for 4:2:2 video). 16 is best when
2922 encoding to most video codecs. Default value is 16.
2924 @item reset_count, reset
2925 Set the counter that determines after how many frames cropdetect will
2926 reset the previously detected largest video area and start over to
2927 detect the current optimal crop area. Default value is 0.
2929 This can be useful when channel logos distort the video area. 0
2930 indicates never reset and return the largest area encountered during
2937 Apply color adjustments using curves.
2939 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
2940 component (red, green and blue) has its values defined by @var{N} key points
2941 tied from each other using a smooth curve. The x-axis represents the pixel
2942 values from the input frame, and the y-axis the new pixel values to be set for
2945 By default, a component curve is defined by the two points @var{(0;0)} and
2946 @var{(1;1)}. This creates a straight line where each original pixel value is
2947 "adjusted" to its own value, which means no change to the image.
2949 The filter allows you to redefine these two points and add some more. A new
2950 curve (using a natural cubic spline interpolation) will be define to pass
2951 smoothly through all these new coordinates. The new defined points needs to be
2952 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
2953 be in the @var{[0;1]} interval. If the computed curves happened to go outside
2954 the vector spaces, the values will be clipped accordingly.
2956 If there is no key point defined in @code{x=0}, the filter will automatically
2957 insert a @var{(0;0)} point. In the same way, if there is no key point defined
2958 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
2960 The filter accepts the following options:
2964 Select one of the available color presets. This option can be used in addition
2965 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
2966 options takes priority on the preset values.
2967 Available presets are:
2970 @item color_negative
2973 @item increase_contrast
2975 @item linear_contrast
2976 @item medium_contrast
2978 @item strong_contrast
2981 Default is @code{none}.
2983 Set the master key points. These points will define a second pass mapping. It
2984 is sometimes called a "luminance" or "value" mapping. It can be used with
2985 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
2986 post-processing LUT.
2988 Set the key points for the red component.
2990 Set the key points for the green component.
2992 Set the key points for the blue component.
2994 Set the key points for all components (not including master).
2995 Can be used in addition to the other key points component
2996 options. In this case, the unset component(s) will fallback on this
2997 @option{all} setting.
2999 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3002 To avoid some filtergraph syntax conflicts, each key points list need to be
3003 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3005 @subsection Examples
3009 Increase slightly the middle level of blue:
3011 curves=blue='0.5/0.58'
3017 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3019 Here we obtain the following coordinates for each components:
3022 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3024 @code{(0;0) (0.50;0.48) (1;1)}
3026 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3030 The previous example can also be achieved with the associated built-in preset:
3032 curves=preset=vintage
3042 Use a Photoshop preset and redefine the points of the green component:
3044 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3050 Denoise frames using 2D DCT (frequency domain filtering).
3052 This filter is not designed for real time and can be extremely slow.
3054 The filter accepts the following options:
3058 Set the noise sigma constant.
3060 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3061 coefficient (absolute value) below this threshold with be dropped.
3063 If you need a more advanced filtering, see @option{expr}.
3065 Default is @code{0}.
3068 Set number overlapping pixels for each block. Each block is of size
3069 @code{16x16}. Since the filter can be slow, you may want to reduce this value,
3070 at the cost of a less effective filter and the risk of various artefacts.
3072 If the overlapping value doesn't allow to process the whole input width or
3073 height, a warning will be displayed and according borders won't be denoised.
3075 Default value is @code{15}.
3078 Set the coefficient factor expression.
3080 For each coefficient of a DCT block, this expression will be evaluated as a
3081 multiplier value for the coefficient.
3083 If this is option is set, the @option{sigma} option will be ignored.
3085 The absolute value of the coefficient can be accessed through the @var{c}
3089 @subsection Examples
3091 Apply a denoise with a @option{sigma} of @code{4.5}:
3096 The same operation can be achieved using the expression system:
3098 dctdnoiz=e='gte(c, 4.5*3)'
3104 Drop duplicated frames at regular intervals.
3106 The filter accepts the following options:
3110 Set the number of frames from which one will be dropped. Setting this to
3111 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3112 Default is @code{5}.
3115 Set the threshold for duplicate detection. If the difference metric for a frame
3116 is less than or equal to this value, then it is declared as duplicate. Default
3120 Set scene change threshold. Default is @code{15}.
3124 Set the size of the x and y-axis blocks used during metric calculations.
3125 Larger blocks give better noise suppression, but also give worse detection of
3126 small movements. Must be a power of two. Default is @code{32}.
3129 Mark main input as a pre-processed input and activate clean source input
3130 stream. This allows the input to be pre-processed with various filters to help
3131 the metrics calculation while keeping the frame selection lossless. When set to
3132 @code{1}, the first stream is for the pre-processed input, and the second
3133 stream is the clean source from where the kept frames are chosen. Default is
3137 Set whether or not chroma is considered in the metric calculations. Default is
3143 Suppress a TV station logo by a simple interpolation of the surrounding
3144 pixels. Just set a rectangle covering the logo and watch it disappear
3145 (and sometimes something even uglier appear - your mileage may vary).
3147 This filter accepts the following options:
3152 Specify the top left corner coordinates of the logo. They must be
3157 Specify the width and height of the logo to clear. They must be
3161 Specify the thickness of the fuzzy edge of the rectangle (added to
3162 @var{w} and @var{h}). The default value is 4.
3165 When set to 1, a green rectangle is drawn on the screen to simplify
3166 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3167 The default value is 0.
3169 The rectangle is drawn on the outermost pixels which will be (partly)
3170 replaced with interpolated values. The values of the next pixels
3171 immediately outside this rectangle in each direction will be used to
3172 compute the interpolated pixel values inside the rectangle.
3176 @subsection Examples
3180 Set a rectangle covering the area with top left corner coordinates 0,0
3181 and size 100x77, setting a band of size 10:
3183 delogo=x=0:y=0:w=100:h=77:band=10
3190 Attempt to fix small changes in horizontal and/or vertical shift. This
3191 filter helps remove camera shake from hand-holding a camera, bumping a
3192 tripod, moving on a vehicle, etc.
3194 The filter accepts the following options:
3202 Specify a rectangular area where to limit the search for motion
3204 If desired the search for motion vectors can be limited to a
3205 rectangular area of the frame defined by its top left corner, width
3206 and height. These parameters have the same meaning as the drawbox
3207 filter which can be used to visualise the position of the bounding
3210 This is useful when simultaneous movement of subjects within the frame
3211 might be confused for camera motion by the motion vector search.
3213 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3214 then the full frame is used. This allows later options to be set
3215 without specifying the bounding box for the motion vector search.
3217 Default - search the whole frame.
3221 Specify the maximum extent of movement in x and y directions in the
3222 range 0-64 pixels. Default 16.
3225 Specify how to generate pixels to fill blanks at the edge of the
3226 frame. Available values are:
3229 Fill zeroes at blank locations
3231 Original image at blank locations
3233 Extruded edge value at blank locations
3235 Mirrored edge at blank locations
3237 Default value is @samp{mirror}.
3240 Specify the blocksize to use for motion search. Range 4-128 pixels,
3244 Specify the contrast threshold for blocks. Only blocks with more than
3245 the specified contrast (difference between darkest and lightest
3246 pixels) will be considered. Range 1-255, default 125.
3249 Specify the search strategy. Available values are:
3252 Set exhaustive search
3254 Set less exhaustive search.
3256 Default value is @samp{exhaustive}.
3259 If set then a detailed log of the motion search is written to the
3263 If set to 1, specify using OpenCL capabilities, only available if
3264 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3270 Draw a colored box on the input image.
3272 This filter accepts the following options:
3277 The expressions which specify the top left corner coordinates of the box. Default to 0.
3281 The expressions which specify the width and height of the box, if 0 they are interpreted as
3282 the input width and height. Default to 0.
3285 Specify the color of the box to write. For the general syntax of this option,
3286 check the "Color" section in the ffmpeg-utils manual. If the special
3287 value @code{invert} is used, the box edge color is the same as the
3288 video with inverted luma.
3291 The expression which sets the thickness of the box edge. Default value is @code{3}.
3293 See below for the list of accepted constants.
3296 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3297 following constants:
3301 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3305 horizontal and vertical chroma subsample values. For example for the
3306 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3310 The input width and height.
3313 The input sample aspect ratio.
3317 The x and y offset coordinates where the box is drawn.
3321 The width and height of the drawn box.
3324 The thickness of the drawn box.
3326 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3327 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3331 @subsection Examples
3335 Draw a black box around the edge of the input image:
3341 Draw a box with color red and an opacity of 50%:
3343 drawbox=10:20:200:60:red@@0.5
3346 The previous example can be specified as:
3348 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3352 Fill the box with pink color:
3354 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3358 Draw a 2-pixel red 2.40:1 mask:
3360 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
3366 Draw a grid on the input image.
3368 This filter accepts the following options:
3373 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3377 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3378 input width and height, respectively, minus @code{thickness}, so image gets
3379 framed. Default to 0.
3382 Specify the color of the grid. For the general syntax of this option,
3383 check the "Color" section in the ffmpeg-utils manual. If the special
3384 value @code{invert} is used, the grid color is the same as the
3385 video with inverted luma.
3388 The expression which sets the thickness of the grid line. Default value is @code{1}.
3390 See below for the list of accepted constants.
3393 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3394 following constants:
3398 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3402 horizontal and vertical chroma subsample values. For example for the
3403 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3407 The input grid cell width and height.
3410 The input sample aspect ratio.
3414 The x and y coordinates of some point of grid intersection (meant to configure offset).
3418 The width and height of the drawn cell.
3421 The thickness of the drawn cell.
3423 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3424 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3428 @subsection Examples
3432 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3434 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3438 Draw a white 3x3 grid with an opacity of 50%:
3440 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3447 Draw text string or text from specified file on top of video using the
3448 libfreetype library.
3450 To enable compilation of this filter you need to configure FFmpeg with
3451 @code{--enable-libfreetype}.
3455 The description of the accepted parameters follows.
3460 Used to draw a box around text using background color.
3461 Value should be either 1 (enable) or 0 (disable).
3462 The default value of @var{box} is 0.
3465 The color to be used for drawing box around text. For the syntax of this
3466 option, check the "Color" section in the ffmpeg-utils manual.
3468 The default value of @var{boxcolor} is "white".
3471 Select how the @var{text} is expanded. Can be either @code{none},
3472 @code{strftime} (deprecated) or
3473 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3477 If true, check and fix text coords to avoid clipping.
3480 The color to be used for drawing fonts. For the syntax of this option, check
3481 the "Color" section in the ffmpeg-utils manual.
3483 The default value of @var{fontcolor} is "black".
3486 The font file to be used for drawing text. Path must be included.
3487 This parameter is mandatory.
3490 The font size to be used for drawing text.
3491 The default value of @var{fontsize} is 16.
3494 Flags to be used for loading the fonts.
3496 The flags map the corresponding flags supported by libfreetype, and are
3497 a combination of the following values:
3504 @item vertical_layout
3505 @item force_autohint
3508 @item ignore_global_advance_width
3510 @item ignore_transform
3516 Default value is "render".
3518 For more information consult the documentation for the FT_LOAD_*
3522 The color to be used for drawing a shadow behind the drawn text. For the
3523 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3525 The default value of @var{shadowcolor} is "black".
3529 The x and y offsets for the text shadow position with respect to the
3530 position of the text. They can be either positive or negative
3531 values. Default value for both is "0".
3534 The starting frame number for the n/frame_num variable. The default value
3538 The size in number of spaces to use for rendering the tab.
3542 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3543 format. It can be used with or without text parameter. @var{timecode_rate}
3544 option must be specified.
3546 @item timecode_rate, rate, r
3547 Set the timecode frame rate (timecode only).
3550 The text string to be drawn. The text must be a sequence of UTF-8
3552 This parameter is mandatory if no file is specified with the parameter
3556 A text file containing text to be drawn. The text must be a sequence
3557 of UTF-8 encoded characters.
3559 This parameter is mandatory if no text string is specified with the
3560 parameter @var{text}.
3562 If both @var{text} and @var{textfile} are specified, an error is thrown.
3565 If set to 1, the @var{textfile} will be reloaded before each frame.
3566 Be sure to update it atomically, or it may be read partially, or even fail.
3570 The expressions which specify the offsets where text will be drawn
3571 within the video frame. They are relative to the top/left border of the
3574 The default value of @var{x} and @var{y} is "0".
3576 See below for the list of accepted constants and functions.
3579 The parameters for @var{x} and @var{y} are expressions containing the
3580 following constants and functions:
3584 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3588 horizontal and vertical chroma subsample values. For example for the
3589 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3592 the height of each text line
3600 @item max_glyph_a, ascent
3601 the maximum distance from the baseline to the highest/upper grid
3602 coordinate used to place a glyph outline point, for all the rendered
3604 It is a positive value, due to the grid's orientation with the Y axis
3607 @item max_glyph_d, descent
3608 the maximum distance from the baseline to the lowest grid coordinate
3609 used to place a glyph outline point, for all the rendered glyphs.
3610 This is a negative value, due to the grid's orientation, with the Y axis
3614 maximum glyph height, that is the maximum height for all the glyphs
3615 contained in the rendered text, it is equivalent to @var{ascent} -
3619 maximum glyph width, that is the maximum width for all the glyphs
3620 contained in the rendered text
3623 the number of input frame, starting from 0
3625 @item rand(min, max)
3626 return a random number included between @var{min} and @var{max}
3629 input sample aspect ratio
3632 timestamp expressed in seconds, NAN if the input timestamp is unknown
3635 the height of the rendered text
3638 the width of the rendered text
3642 the x and y offset coordinates where the text is drawn.
3644 These parameters allow the @var{x} and @var{y} expressions to refer
3645 each other, so you can for example specify @code{y=x/dar}.
3648 If libavfilter was built with @code{--enable-fontconfig}, then
3649 @option{fontfile} can be a fontconfig pattern or omitted.
3651 @anchor{drawtext_expansion}
3652 @subsection Text expansion
3654 If @option{expansion} is set to @code{strftime},
3655 the filter recognizes strftime() sequences in the provided text and
3656 expands them accordingly. Check the documentation of strftime(). This
3657 feature is deprecated.
3659 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3661 If @option{expansion} is set to @code{normal} (which is the default),
3662 the following expansion mechanism is used.
3664 The backslash character '\', followed by any character, always expands to
3665 the second character.
3667 Sequence of the form @code{%@{...@}} are expanded. The text between the
3668 braces is a function name, possibly followed by arguments separated by ':'.
3669 If the arguments contain special characters or delimiters (':' or '@}'),
3670 they should be escaped.
3672 Note that they probably must also be escaped as the value for the
3673 @option{text} option in the filter argument string and as the filter
3674 argument in the filtergraph description, and possibly also for the shell,
3675 that makes up to four levels of escaping; using a text file avoids these
3678 The following functions are available:
3683 The expression evaluation result.
3685 It must take one argument specifying the expression to be evaluated,
3686 which accepts the same constants and functions as the @var{x} and
3687 @var{y} values. Note that not all constants should be used, for
3688 example the text size is not known when evaluating the expression, so
3689 the constants @var{text_w} and @var{text_h} will have an undefined
3693 The time at which the filter is running, expressed in UTC.
3694 It can accept an argument: a strftime() format string.
3697 The time at which the filter is running, expressed in the local time zone.
3698 It can accept an argument: a strftime() format string.
3701 Frame metadata. It must take one argument specifying metadata key.
3704 The frame number, starting from 0.
3707 A 1 character description of the current picture type.
3710 The timestamp of the current frame, in seconds, with microsecond accuracy.
3714 @subsection Examples
3718 Draw "Test Text" with font FreeSerif, using the default values for the
3719 optional parameters.
3722 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
3726 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
3727 and y=50 (counting from the top-left corner of the screen), text is
3728 yellow with a red box around it. Both the text and the box have an
3732 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
3733 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
3736 Note that the double quotes are not necessary if spaces are not used
3737 within the parameter list.
3740 Show the text at the center of the video frame:
3742 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
3746 Show a text line sliding from right to left in the last row of the video
3747 frame. The file @file{LONG_LINE} is assumed to contain a single line
3750 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
3754 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
3756 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
3760 Draw a single green letter "g", at the center of the input video.
3761 The glyph baseline is placed at half screen height.
3763 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
3767 Show text for 1 second every 3 seconds:
3769 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
3773 Use fontconfig to set the font. Note that the colons need to be escaped.
3775 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
3779 Print the date of a real-time encoding (see strftime(3)):
3781 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
3786 For more information about libfreetype, check:
3787 @url{http://www.freetype.org/}.
3789 For more information about fontconfig, check:
3790 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
3794 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
3796 The filter accepts the following options:
3801 Set low and high threshold values used by the Canny thresholding
3804 The high threshold selects the "strong" edge pixels, which are then
3805 connected through 8-connectivity with the "weak" edge pixels selected
3806 by the low threshold.
3808 @var{low} and @var{high} threshold values must be choosen in the range
3809 [0,1], and @var{low} should be lesser or equal to @var{high}.
3811 Default value for @var{low} is @code{20/255}, and default value for @var{high}
3817 edgedetect=low=0.1:high=0.4
3820 @section extractplanes
3822 Extract color channel components from input video stream into
3823 separate grayscale video streams.
3825 The filter accepts the following option:
3829 Set plane(s) to extract.
3831 Available values for planes are:
3842 Choosing planes not available in the input will result in an error.
3843 That means you cannot select @code{r}, @code{g}, @code{b} planes
3844 with @code{y}, @code{u}, @code{v} planes at same time.
3847 @subsection Examples
3851 Extract luma, u and v color channel component from input video frame
3852 into 3 grayscale outputs:
3854 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
3860 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
3862 For each input image, the filter will compute the optimal mapping from
3863 the input to the output given the codebook length, that is the number
3864 of distinct output colors.
3866 This filter accepts the following options.
3869 @item codebook_length, l
3870 Set codebook length. The value must be a positive integer, and
3871 represents the number of distinct output colors. Default value is 256.
3874 Set the maximum number of iterations to apply for computing the optimal
3875 mapping. The higher the value the better the result and the higher the
3876 computation time. Default value is 1.
3879 Set a random seed, must be an integer included between 0 and
3880 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
3881 will try to use a good random seed on a best effort basis.
3886 Apply fade-in/out effect to input video.
3888 This filter accepts the following options:
3892 The effect type -- can be either "in" for fade-in, or "out" for a fade-out
3894 Default is @code{in}.
3896 @item start_frame, s
3897 Specify the number of the start frame for starting to apply the fade
3898 effect. Default is 0.
3901 The number of frames for which the fade effect has to last. At the end of the
3902 fade-in effect the output video will have the same intensity as the input video,
3903 at the end of the fade-out transition the output video will be filled with the
3904 selected @option{color}.
3908 If set to 1, fade only alpha channel, if one exists on the input.
3911 @item start_time, st
3912 Specify the timestamp (in seconds) of the frame to start to apply the fade
3913 effect. If both start_frame and start_time are specified, the fade will start at
3914 whichever comes last. Default is 0.
3917 The number of seconds for which the fade effect has to last. At the end of the
3918 fade-in effect the output video will have the same intensity as the input video,
3919 at the end of the fade-out transition the output video will be filled with the
3920 selected @option{color}.
3921 If both duration and nb_frames are specified, duration is used. Default is 0.
3924 Specify the color of the fade. Default is "black".
3927 @subsection Examples
3931 Fade in first 30 frames of video:
3936 The command above is equivalent to:
3942 Fade out last 45 frames of a 200-frame video:
3945 fade=type=out:start_frame=155:nb_frames=45
3949 Fade in first 25 frames and fade out last 25 frames of a 1000-frame video:
3951 fade=in:0:25, fade=out:975:25
3955 Make first 5 frames yellow, then fade in from frame 5-24:
3957 fade=in:5:20:color=yellow
3961 Fade in alpha over first 25 frames of video:
3963 fade=in:0:25:alpha=1
3967 Make first 5.5 seconds black, then fade in for 0.5 seconds:
3969 fade=t=in:st=5.5:d=0.5
3976 Extract a single field from an interlaced image using stride
3977 arithmetic to avoid wasting CPU time. The output frames are marked as
3980 The filter accepts the following options:
3984 Specify whether to extract the top (if the value is @code{0} or
3985 @code{top}) or the bottom field (if the value is @code{1} or
3991 Field matching filter for inverse telecine. It is meant to reconstruct the
3992 progressive frames from a telecined stream. The filter does not drop duplicated
3993 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
3994 followed by a decimation filter such as @ref{decimate} in the filtergraph.
3996 The separation of the field matching and the decimation is notably motivated by
3997 the possibility of inserting a de-interlacing filter fallback between the two.
3998 If the source has mixed telecined and real interlaced content,
3999 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4000 But these remaining combed frames will be marked as interlaced, and thus can be
4001 de-interlaced by a later filter such as @ref{yadif} before decimation.
4003 In addition to the various configuration options, @code{fieldmatch} can take an
4004 optional second stream, activated through the @option{ppsrc} option. If
4005 enabled, the frames reconstruction will be based on the fields and frames from
4006 this second stream. This allows the first input to be pre-processed in order to
4007 help the various algorithms of the filter, while keeping the output lossless
4008 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4009 or brightness/contrast adjustments can help.
4011 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4012 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4013 which @code{fieldmatch} is based on. While the semantic and usage are very
4014 close, some behaviour and options names can differ.
4016 The filter accepts the following options:
4020 Specify the assumed field order of the input stream. Available values are:
4024 Auto detect parity (use FFmpeg's internal parity value).
4026 Assume bottom field first.
4028 Assume top field first.
4031 Note that it is sometimes recommended not to trust the parity announced by the
4034 Default value is @var{auto}.
4037 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4038 sense that it won't risk creating jerkiness due to duplicate frames when
4039 possible, but if there are bad edits or blended fields it will end up
4040 outputting combed frames when a good match might actually exist. On the other
4041 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4042 but will almost always find a good frame if there is one. The other values are
4043 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4044 jerkiness and creating duplicate frames versus finding good matches in sections
4045 with bad edits, orphaned fields, blended fields, etc.
4047 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4049 Available values are:
4053 2-way matching (p/c)
4055 2-way matching, and trying 3rd match if still combed (p/c + n)
4057 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4059 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4060 still combed (p/c + n + u/b)
4062 3-way matching (p/c/n)
4064 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4065 detected as combed (p/c/n + u/b)
4068 The parenthesis at the end indicate the matches that would be used for that
4069 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4072 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4075 Default value is @var{pc_n}.
4078 Mark the main input stream as a pre-processed input, and enable the secondary
4079 input stream as the clean source to pick the fields from. See the filter
4080 introduction for more details. It is similar to the @option{clip2} feature from
4083 Default value is @code{0} (disabled).
4086 Set the field to match from. It is recommended to set this to the same value as
4087 @option{order} unless you experience matching failures with that setting. In
4088 certain circumstances changing the field that is used to match from can have a
4089 large impact on matching performance. Available values are:
4093 Automatic (same value as @option{order}).
4095 Match from the bottom field.
4097 Match from the top field.
4100 Default value is @var{auto}.
4103 Set whether or not chroma is included during the match comparisons. In most
4104 cases it is recommended to leave this enabled. You should set this to @code{0}
4105 only if your clip has bad chroma problems such as heavy rainbowing or other
4106 artifacts. Setting this to @code{0} could also be used to speed things up at
4107 the cost of some accuracy.
4109 Default value is @code{1}.
4113 These define an exclusion band which excludes the lines between @option{y0} and
4114 @option{y1} from being included in the field matching decision. An exclusion
4115 band can be used to ignore subtitles, a logo, or other things that may
4116 interfere with the matching. @option{y0} sets the starting scan line and
4117 @option{y1} sets the ending line; all lines in between @option{y0} and
4118 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4119 @option{y0} and @option{y1} to the same value will disable the feature.
4120 @option{y0} and @option{y1} defaults to @code{0}.
4123 Set the scene change detection threshold as a percentage of maximum change on
4124 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4125 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4126 @option{scthresh} is @code{[0.0, 100.0]}.
4128 Default value is @code{12.0}.
4131 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4132 account the combed scores of matches when deciding what match to use as the
4133 final match. Available values are:
4137 No final matching based on combed scores.
4139 Combed scores are only used when a scene change is detected.
4141 Use combed scores all the time.
4144 Default is @var{sc}.
4147 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4148 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4149 Available values are:
4153 No forced calculation.
4155 Force p/c/n calculations.
4157 Force p/c/n/u/b calculations.
4160 Default value is @var{none}.
4163 This is the area combing threshold used for combed frame detection. This
4164 essentially controls how "strong" or "visible" combing must be to be detected.
4165 Larger values mean combing must be more visible and smaller values mean combing
4166 can be less visible or strong and still be detected. Valid settings are from
4167 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4168 be detected as combed). This is basically a pixel difference value. A good
4169 range is @code{[8, 12]}.
4171 Default value is @code{9}.
4174 Sets whether or not chroma is considered in the combed frame decision. Only
4175 disable this if your source has chroma problems (rainbowing, etc.) that are
4176 causing problems for the combed frame detection with chroma enabled. Actually,
4177 using @option{chroma}=@var{0} is usually more reliable, except for the case
4178 where there is chroma only combing in the source.
4180 Default value is @code{0}.
4184 Respectively set the x-axis and y-axis size of the window used during combed
4185 frame detection. This has to do with the size of the area in which
4186 @option{combpel} pixels are required to be detected as combed for a frame to be
4187 declared combed. See the @option{combpel} parameter description for more info.
4188 Possible values are any number that is a power of 2 starting at 4 and going up
4191 Default value is @code{16}.
4194 The number of combed pixels inside any of the @option{blocky} by
4195 @option{blockx} size blocks on the frame for the frame to be detected as
4196 combed. While @option{cthresh} controls how "visible" the combing must be, this
4197 setting controls "how much" combing there must be in any localized area (a
4198 window defined by the @option{blockx} and @option{blocky} settings) on the
4199 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4200 which point no frames will ever be detected as combed). This setting is known
4201 as @option{MI} in TFM/VFM vocabulary.
4203 Default value is @code{80}.
4206 @anchor{p/c/n/u/b meaning}
4207 @subsection p/c/n/u/b meaning
4209 @subsubsection p/c/n
4211 We assume the following telecined stream:
4214 Top fields: 1 2 2 3 4
4215 Bottom fields: 1 2 3 4 4
4218 The numbers correspond to the progressive frame the fields relate to. Here, the
4219 first two frames are progressive, the 3rd and 4th are combed, and so on.
4221 When @code{fieldmatch} is configured to run a matching from bottom
4222 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4227 B 1 2 3 4 4 <-- matching reference
4236 As a result of the field matching, we can see that some frames get duplicated.
4237 To perform a complete inverse telecine, you need to rely on a decimation filter
4238 after this operation. See for instance the @ref{decimate} filter.
4240 The same operation now matching from top fields (@option{field}=@var{top})
4245 T 1 2 2 3 4 <-- matching reference
4255 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4256 basically, they refer to the frame and field of the opposite parity:
4259 @item @var{p} matches the field of the opposite parity in the previous frame
4260 @item @var{c} matches the field of the opposite parity in the current frame
4261 @item @var{n} matches the field of the opposite parity in the next frame
4266 The @var{u} and @var{b} matching are a bit special in the sense that they match
4267 from the opposite parity flag. In the following examples, we assume that we are
4268 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4269 'x' is placed above and below each matched fields.
4271 With bottom matching (@option{field}=@var{bottom}):
4276 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4277 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4285 With top matching (@option{field}=@var{top}):
4290 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4291 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4299 @subsection Examples
4301 Simple IVTC of a top field first telecined stream:
4303 fieldmatch=order=tff:combmatch=none, decimate
4306 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4308 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4313 Transform the field order of the input video.
4315 This filter accepts the following options:
4320 Output field order. Valid values are @var{tff} for top field first or @var{bff}
4321 for bottom field first.
4324 Default value is @samp{tff}.
4326 Transformation is achieved by shifting the picture content up or down
4327 by one line, and filling the remaining line with appropriate picture content.
4328 This method is consistent with most broadcast field order converters.
4330 If the input video is not flagged as being interlaced, or it is already
4331 flagged as being of the required output field order then this filter does
4332 not alter the incoming video.
4334 This filter is very useful when converting to or from PAL DV material,
4335 which is bottom field first.
4339 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4344 Buffer input images and send them when they are requested.
4346 This filter is mainly useful when auto-inserted by the libavfilter
4349 The filter does not take parameters.
4354 Convert the input video to one of the specified pixel formats.
4355 Libavfilter will try to pick one that is supported for the input to
4358 This filter accepts the following parameters:
4362 A '|'-separated list of pixel format names, for example
4363 "pix_fmts=yuv420p|monow|rgb24".
4367 @subsection Examples
4371 Convert the input video to the format @var{yuv420p}
4373 format=pix_fmts=yuv420p
4376 Convert the input video to any of the formats in the list
4378 format=pix_fmts=yuv420p|yuv444p|yuv410p
4385 Convert the video to specified constant frame rate by duplicating or dropping
4386 frames as necessary.
4388 This filter accepts the following named parameters:
4392 Desired output frame rate. The default is @code{25}.
4397 Possible values are:
4400 zero round towards 0
4404 round towards -infinity
4406 round towards +infinity
4410 The default is @code{near}.
4413 Assume the first PTS should be the given value, in seconds. This allows for
4414 padding/trimming at the start of stream. By default, no assumption is made
4415 about the first frame's expected PTS, so no padding or trimming is done.
4416 For example, this could be set to 0 to pad the beginning with duplicates of
4417 the first frame if a video stream starts after the audio stream or to trim any
4418 frames with a negative PTS.
4422 Alternatively, the options can be specified as a flat string:
4423 @var{fps}[:@var{round}].
4425 See also the @ref{setpts} filter.
4427 @subsection Examples
4431 A typical usage in order to set the fps to 25:
4437 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4439 fps=fps=film:round=near
4445 Select one frame every N-th frame.
4447 This filter accepts the following option:
4450 Select frame after every @code{step} frames.
4451 Allowed values are positive integers higher than 0. Default value is @code{1}.
4457 Apply a frei0r effect to the input video.
4459 To enable compilation of this filter you need to install the frei0r
4460 header and configure FFmpeg with @code{--enable-frei0r}.
4462 This filter accepts the following options:
4467 The name to the frei0r effect to load. If the environment variable
4468 @env{FREI0R_PATH} is defined, the frei0r effect is searched in each one of the
4469 directories specified by the colon separated list in @env{FREIOR_PATH},
4470 otherwise in the standard frei0r paths, which are in this order:
4471 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
4472 @file{/usr/lib/frei0r-1/}.
4475 A '|'-separated list of parameters to pass to the frei0r effect.
4479 A frei0r effect parameter can be a boolean (whose values are specified
4480 with "y" and "n"), a double, a color (specified by the syntax
4481 @var{R}/@var{G}/@var{B}, (@var{R}, @var{G}, and @var{B} being float
4482 numbers from 0.0 to 1.0) or by a color description specified in the "Color"
4483 section in the ffmpeg-utils manual), a position (specified by the syntax @var{X}/@var{Y},
4484 @var{X} and @var{Y} being float numbers) and a string.
4486 The number and kind of parameters depend on the loaded effect. If an
4487 effect parameter is not specified the default value is set.
4489 @subsection Examples
4493 Apply the distort0r effect, set the first two double parameters:
4495 frei0r=filter_name=distort0r:filter_params=0.5|0.01
4499 Apply the colordistance effect, take a color as first parameter:
4501 frei0r=colordistance:0.2/0.3/0.4
4502 frei0r=colordistance:violet
4503 frei0r=colordistance:0x112233
4507 Apply the perspective effect, specify the top left and top right image
4510 frei0r=perspective:0.2/0.2|0.8/0.2
4514 For more information see:
4515 @url{http://frei0r.dyne.org}
4519 The filter accepts the following options:
4523 Set the luminance expression.
4525 Set the chrominance blue expression.
4527 Set the chrominance red expression.
4529 Set the alpha expression.
4531 Set the red expression.
4533 Set the green expression.
4535 Set the blue expression.
4538 The colorspace is selected according to the specified options. If one
4539 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4540 options is specified, the filter will automatically select a YCbCr
4541 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4542 @option{blue_expr} options is specified, it will select an RGB
4545 If one of the chrominance expression is not defined, it falls back on the other
4546 one. If no alpha expression is specified it will evaluate to opaque value.
4547 If none of chrominance expressions are specified, they will evaluate
4548 to the luminance expression.
4550 The expressions can use the following variables and functions:
4554 The sequential number of the filtered frame, starting from @code{0}.
4558 The coordinates of the current sample.
4562 The width and height of the image.
4566 Width and height scale depending on the currently filtered plane. It is the
4567 ratio between the corresponding luma plane number of pixels and the current
4568 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4569 @code{0.5,0.5} for chroma planes.
4572 Time of the current frame, expressed in seconds.
4575 Return the value of the pixel at location (@var{x},@var{y}) of the current
4579 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
4583 Return the value of the pixel at location (@var{x},@var{y}) of the
4584 blue-difference chroma plane. Return 0 if there is no such plane.
4587 Return the value of the pixel at location (@var{x},@var{y}) of the
4588 red-difference chroma plane. Return 0 if there is no such plane.
4593 Return the value of the pixel at location (@var{x},@var{y}) of the
4594 red/green/blue component. Return 0 if there is no such component.
4597 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
4598 plane. Return 0 if there is no such plane.
4601 For functions, if @var{x} and @var{y} are outside the area, the value will be
4602 automatically clipped to the closer edge.
4604 @subsection Examples
4608 Flip the image horizontally:
4614 Generate a bidimensional sine wave, with angle @code{PI/3} and a
4615 wavelength of 100 pixels:
4617 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
4621 Generate a fancy enigmatic moving light:
4623 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
4627 Generate a quick emboss effect:
4629 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
4633 Modify RGB components depending on pixel position:
4635 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
4641 Fix the banding artifacts that are sometimes introduced into nearly flat
4642 regions by truncation to 8bit color depth.
4643 Interpolate the gradients that should go where the bands are, and
4646 This filter is designed for playback only. Do not use it prior to
4647 lossy compression, because compression tends to lose the dither and
4648 bring back the bands.
4650 This filter accepts the following options:
4655 The maximum amount by which the filter will change any one pixel. Also the
4656 threshold for detecting nearly flat regions. Acceptable values range from .51 to
4657 64, default value is 1.2, out-of-range values will be clipped to the valid
4661 The neighborhood to fit the gradient to. A larger radius makes for smoother
4662 gradients, but also prevents the filter from modifying the pixels near detailed
4663 regions. Acceptable values are 8-32, default value is 16, out-of-range values
4664 will be clipped to the valid range.
4668 Alternatively, the options can be specified as a flat string:
4669 @var{strength}[:@var{radius}]
4671 @subsection Examples
4675 Apply the filter with a @code{3.5} strength and radius of @code{8}:
4681 Specify radius, omitting the strength (which will fall-back to the default
4692 Apply a Hald CLUT to a video stream.
4694 First input is the video stream to process, and second one is the Hald CLUT.
4695 The Hald CLUT input can be a simple picture or a complete video stream.
4697 The filter accepts the following options:
4701 Force termination when the shortest input terminates. Default is @code{0}.
4703 Continue applying the last CLUT after the end of the stream. A value of
4704 @code{0} disable the filter after the last frame of the CLUT is reached.
4705 Default is @code{1}.
4708 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
4709 filters share the same internals).
4711 More information about the Hald CLUT can be found on Eskil Steenberg's website
4712 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
4714 @subsection Workflow examples
4716 @subsubsection Hald CLUT video stream
4718 Generate an identity Hald CLUT stream altered with various effects:
4720 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
4723 Note: make sure you use a lossless codec.
4725 Then use it with @code{haldclut} to apply it on some random stream:
4727 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
4730 The Hald CLUT will be applied to the 10 first seconds (duration of
4731 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
4732 to the remaining frames of the @code{mandelbrot} stream.
4734 @subsubsection Hald CLUT with preview
4736 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
4737 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
4738 biggest possible square starting at the top left of the picture. The remaining
4739 padding pixels (bottom or right) will be ignored. This area can be used to add
4740 a preview of the Hald CLUT.
4742 Typically, the following generated Hald CLUT will be supported by the
4743 @code{haldclut} filter:
4746 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
4747 pad=iw+320 [padded_clut];
4748 smptebars=s=320x256, split [a][b];
4749 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
4750 [main][b] overlay=W-320" -frames:v 1 clut.png
4753 It contains the original and a preview of the effect of the CLUT: SMPTE color
4754 bars are displayed on the right-top, and below the same color bars processed by
4757 Then, the effect of this Hald CLUT can be visualized with:
4759 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
4764 Flip the input video horizontally.
4766 For example to horizontally flip the input video with @command{ffmpeg}:
4768 ffmpeg -i in.avi -vf "hflip" out.avi
4772 This filter applies a global color histogram equalization on a
4775 It can be used to correct video that has a compressed range of pixel
4776 intensities. The filter redistributes the pixel intensities to
4777 equalize their distribution across the intensity range. It may be
4778 viewed as an "automatically adjusting contrast filter". This filter is
4779 useful only for correcting degraded or poorly captured source
4782 The filter accepts the following options:
4786 Determine the amount of equalization to be applied. As the strength
4787 is reduced, the distribution of pixel intensities more-and-more
4788 approaches that of the input frame. The value must be a float number
4789 in the range [0,1] and defaults to 0.200.
4792 Set the maximum intensity that can generated and scale the output
4793 values appropriately. The strength should be set as desired and then
4794 the intensity can be limited if needed to avoid washing-out. The value
4795 must be a float number in the range [0,1] and defaults to 0.210.
4798 Set the antibanding level. If enabled the filter will randomly vary
4799 the luminance of output pixels by a small amount to avoid banding of
4800 the histogram. Possible values are @code{none}, @code{weak} or
4801 @code{strong}. It defaults to @code{none}.
4806 Compute and draw a color distribution histogram for the input video.
4808 The computed histogram is a representation of distribution of color components
4811 The filter accepts the following options:
4817 It accepts the following values:
4820 standard histogram that display color components distribution in an image.
4821 Displays color graph for each color component. Shows distribution
4822 of the Y, U, V, A or R, G, B components, depending on input format,
4823 in current frame. Bellow each graph is color component scale meter.
4826 chroma values in vectorscope, if brighter more such chroma values are
4827 distributed in an image.
4828 Displays chroma values (U/V color placement) in two dimensional graph
4829 (which is called a vectorscope). It can be used to read of the hue and
4830 saturation of the current frame. At a same time it is a histogram.
4831 The whiter a pixel in the vectorscope, the more pixels of the input frame
4832 correspond to that pixel (that is the more pixels have this chroma value).
4833 The V component is displayed on the horizontal (X) axis, with the leftmost
4834 side being V = 0 and the rightmost side being V = 255.
4835 The U component is displayed on the vertical (Y) axis, with the top
4836 representing U = 0 and the bottom representing U = 255.
4838 The position of a white pixel in the graph corresponds to the chroma value
4839 of a pixel of the input clip. So the graph can be used to read of the
4840 hue (color flavor) and the saturation (the dominance of the hue in the color).
4841 As the hue of a color changes, it moves around the square. At the center of
4842 the square, the saturation is zero, which means that the corresponding pixel
4843 has no color. If you increase the amount of a specific color, while leaving
4844 the other colors unchanged, the saturation increases, and you move towards
4845 the edge of the square.
4848 chroma values in vectorscope, similar as @code{color} but actual chroma values
4852 per row/column color component graph. In row mode graph in the left side represents
4853 color component value 0 and right side represents value = 255. In column mode top
4854 side represents color component value = 0 and bottom side represents value = 255.
4856 Default value is @code{levels}.
4859 Set height of level in @code{levels}. Default value is @code{200}.
4860 Allowed range is [50, 2048].
4863 Set height of color scale in @code{levels}. Default value is @code{12}.
4864 Allowed range is [0, 40].
4867 Set step for @code{waveform} mode. Smaller values are useful to find out how much
4868 of same luminance values across input rows/columns are distributed.
4869 Default value is @code{10}. Allowed range is [1, 255].
4872 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
4873 Default is @code{row}.
4875 @item waveform_mirror
4876 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
4877 means mirrored. In mirrored mode, higher values will be represented on the left
4878 side for @code{row} mode and at the top for @code{column} mode. Default is
4879 @code{0} (unmirrored).
4882 Set display mode for @code{waveform} and @code{levels}.
4883 It accepts the following values:
4886 Display separate graph for the color components side by side in
4887 @code{row} waveform mode or one below other in @code{column} waveform mode
4888 for @code{waveform} histogram mode. For @code{levels} histogram mode
4889 per color component graphs are placed one bellow other.
4891 This display mode in @code{waveform} histogram mode makes it easy to spot
4892 color casts in the highlights and shadows of an image, by comparing the
4893 contours of the top and the bottom of each waveform.
4894 Since whites, grays, and blacks are characterized by
4895 exactly equal amounts of red, green, and blue, neutral areas of the
4896 picture should display three waveforms of roughly equal width/height.
4897 If not, the correction is easy to make by making adjustments to level the
4901 Presents information that's identical to that in the @code{parade}, except
4902 that the graphs representing color components are superimposed directly
4905 This display mode in @code{waveform} histogram mode can make it easier to spot
4906 the relative differences or similarities in overlapping areas of the color
4907 components that are supposed to be identical, such as neutral whites, grays,
4910 Default is @code{parade}.
4913 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
4914 Default is @code{linear}.
4917 @subsection Examples
4922 Calculate and draw histogram:
4924 ffplay -i input -vf histogram
4932 High precision/quality 3d denoise filter. This filter aims to reduce
4933 image noise producing smooth images and making still images really
4934 still. It should enhance compressibility.
4936 It accepts the following optional parameters:
4940 a non-negative float number which specifies spatial luma strength,
4943 @item chroma_spatial
4944 a non-negative float number which specifies spatial chroma strength,
4945 defaults to 3.0*@var{luma_spatial}/4.0
4948 a float number which specifies luma temporal strength, defaults to
4949 6.0*@var{luma_spatial}/4.0
4952 a float number which specifies chroma temporal strength, defaults to
4953 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
4958 Modify the hue and/or the saturation of the input.
4960 This filter accepts the following options:
4964 Specify the hue angle as a number of degrees. It accepts an expression,
4965 and defaults to "0".
4968 Specify the saturation in the [-10,10] range. It accepts an expression and
4972 Specify the hue angle as a number of radians. It accepts an
4973 expression, and defaults to "0".
4976 Specify the brightness in the [-10,10] range. It accepts an expression and
4980 @option{h} and @option{H} are mutually exclusive, and can't be
4981 specified at the same time.
4983 The @option{b}, @option{h}, @option{H} and @option{s} option values are
4984 expressions containing the following constants:
4988 frame count of the input frame starting from 0
4991 presentation timestamp of the input frame expressed in time base units
4994 frame rate of the input video, NAN if the input frame rate is unknown
4997 timestamp expressed in seconds, NAN if the input timestamp is unknown
5000 time base of the input video
5003 @subsection Examples
5007 Set the hue to 90 degrees and the saturation to 1.0:
5013 Same command but expressing the hue in radians:
5019 Rotate hue and make the saturation swing between 0
5020 and 2 over a period of 1 second:
5022 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5026 Apply a 3 seconds saturation fade-in effect starting at 0:
5031 The general fade-in expression can be written as:
5033 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5037 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5039 hue="s=max(0\, min(1\, (8-t)/3))"
5042 The general fade-out expression can be written as:
5044 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5049 @subsection Commands
5051 This filter supports the following commands:
5057 Modify the hue and/or the saturation and/or brightness of the input video.
5058 The command accepts the same syntax of the corresponding option.
5060 If the specified expression is not valid, it is kept at its current
5066 Detect video interlacing type.
5068 This filter tries to detect if the input is interlaced or progressive,
5069 top or bottom field first.
5071 The filter accepts the following options:
5075 Set interlacing threshold.
5077 Set progressive threshold.
5082 Deinterleave or interleave fields.
5084 This filter allows to process interlaced images fields without
5085 deinterlacing them. Deinterleaving splits the input frame into 2
5086 fields (so called half pictures). Odd lines are moved to the top
5087 half of the output image, even lines to the bottom half.
5088 You can process (filter) them independently and then re-interleave them.
5090 The filter accepts the following options:
5094 @item chroma_mode, c
5096 Available values for @var{luma_mode}, @var{chroma_mode} and
5097 @var{alpha_mode} are:
5103 @item deinterleave, d
5104 Deinterleave fields, placing one above the other.
5107 Interleave fields. Reverse the effect of deinterleaving.
5109 Default value is @code{none}.
5112 @item chroma_swap, cs
5113 @item alpha_swap, as
5114 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5119 Simple interlacing filter from progressive contents. This interleaves upper (or
5120 lower) lines from odd frames with lower (or upper) lines from even frames,
5121 halving the frame rate and preserving image height.
5124 Original Original New Frame
5125 Frame 'j' Frame 'j+1' (tff)
5126 ========== =========== ==================
5127 Line 0 --------------------> Frame 'j' Line 0
5128 Line 1 Line 1 ----> Frame 'j+1' Line 1
5129 Line 2 ---------------------> Frame 'j' Line 2
5130 Line 3 Line 3 ----> Frame 'j+1' Line 3
5132 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5135 It accepts the following optional parameters:
5139 determines whether the interlaced frame is taken from the even (tff - default)
5140 or odd (bff) lines of the progressive frame.
5143 Enable (default) or disable the vertical lowpass filter to avoid twitter
5144 interlacing and reduce moire patterns.
5149 Deinterlace input video by applying Donald Graft's adaptive kernel
5150 deinterling. Work on interlaced parts of a video to produce
5153 The description of the accepted parameters follows.
5157 Set the threshold which affects the filter's tolerance when
5158 determining if a pixel line must be processed. It must be an integer
5159 in the range [0,255] and defaults to 10. A value of 0 will result in
5160 applying the process on every pixels.
5163 Paint pixels exceeding the threshold value to white if set to 1.
5167 Set the fields order. Swap fields if set to 1, leave fields alone if
5171 Enable additional sharpening if set to 1. Default is 0.
5174 Enable twoway sharpening if set to 1. Default is 0.
5177 @subsection Examples
5181 Apply default values:
5183 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5187 Enable additional sharpening:
5193 Paint processed pixels in white:
5202 Apply a 3D LUT to an input video.
5204 The filter accepts the following options:
5208 Set the 3D LUT file name.
5210 Currently supported formats:
5222 Select interpolation mode.
5224 Available values are:
5228 Use values from the nearest defined point.
5230 Interpolate values using the 8 points defining a cube.
5232 Interpolate values using a tetrahedron.
5236 @section lut, lutrgb, lutyuv
5238 Compute a look-up table for binding each pixel component input value
5239 to an output value, and apply it to input video.
5241 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5242 to an RGB input video.
5244 These filters accept the following options:
5247 set first pixel component expression
5249 set second pixel component expression
5251 set third pixel component expression
5253 set fourth pixel component expression, corresponds to the alpha component
5256 set red component expression
5258 set green component expression
5260 set blue component expression
5262 alpha component expression
5265 set Y/luminance component expression
5267 set U/Cb component expression
5269 set V/Cr component expression
5272 Each of them specifies the expression to use for computing the lookup table for
5273 the corresponding pixel component values.
5275 The exact component associated to each of the @var{c*} options depends on the
5278 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5279 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5281 The expressions can contain the following constants and functions:
5286 the input width and height
5289 input value for the pixel component
5292 the input value clipped in the @var{minval}-@var{maxval} range
5295 maximum value for the pixel component
5298 minimum value for the pixel component
5301 the negated value for the pixel component value clipped in the
5302 @var{minval}-@var{maxval} range , it corresponds to the expression
5303 "maxval-clipval+minval"
5306 the computed value in @var{val} clipped in the
5307 @var{minval}-@var{maxval} range
5309 @item gammaval(gamma)
5310 the computed gamma correction value of the pixel component value
5311 clipped in the @var{minval}-@var{maxval} range, corresponds to the
5313 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
5317 All expressions default to "val".
5319 @subsection Examples
5325 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
5326 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
5329 The above is the same as:
5331 lutrgb="r=negval:g=negval:b=negval"
5332 lutyuv="y=negval:u=negval:v=negval"
5342 Remove chroma components, turns the video into a graytone image:
5344 lutyuv="u=128:v=128"
5348 Apply a luma burning effect:
5354 Remove green and blue components:
5360 Set a constant alpha channel value on input:
5362 format=rgba,lutrgb=a="maxval-minval/2"
5366 Correct luminance gamma by a 0.5 factor:
5368 lutyuv=y=gammaval(0.5)
5372 Discard least significant bits of luma:
5374 lutyuv=y='bitand(val, 128+64+32)'
5378 @section mergeplanes
5380 Merge color channel components from several video streams.
5382 The filter accepts up to 4 input streams, and merge selected input
5383 planes to the output video.
5385 This filter accepts the following options:
5388 Set input to output plane mapping. Default is @code{0}.
5390 The mappings is specified as a bitmap. It should be specified as a
5391 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
5392 mapping for the first plane of the output stream. 'A' sets the number of
5393 the input stream to use (from 0 to 3), and 'a' the plane number of the
5394 corresponding input to use (from 0 to 3). The rest of the mappings is
5395 similar, 'Bb' describes the mapping for the output stream second
5396 plane, 'Cc' describes the mapping for the output stream third plane and
5397 'Dd' describes the mapping for the output stream fourth plane.
5400 Set output pixel format. Default is @code{yuva444p}.
5403 @subsection Examples
5407 Merge three gray video streams of same width and height into single video stream:
5409 [a0][a1][a2]mergeplanes=0x001020:yuv444p
5413 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
5415 [a0][a1]mergeplanes=0x00010210:yuva444p
5419 Swap Y and A plane in yuva444p stream:
5421 format=yuva444p,mergeplanes=0x03010200:yuva444p
5425 Swap U and V plane in yuv420p stream:
5427 format=yuv420p,mergeplanes=0x000201:yuv420p
5431 Cast a rgb24 clip to yuv444p:
5433 format=rgb24,mergeplanes=0x000102:yuv444p
5439 Apply motion-compensation deinterlacing.
5441 It needs one field per frame as input and must thus be used together
5442 with yadif=1/3 or equivalent.
5444 This filter accepts the following options:
5447 Set the deinterlacing mode.
5449 It accepts one of the following values:
5454 use iterative motion estimation
5456 like @samp{slow}, but use multiple reference frames.
5458 Default value is @samp{fast}.
5461 Set the picture field parity assumed for the input video. It must be
5462 one of the following values:
5466 assume top field first
5468 assume bottom field first
5471 Default value is @samp{bff}.
5474 Set per-block quantization parameter (QP) used by the internal
5477 Higher values should result in a smoother motion vector field but less
5478 optimal individual vectors. Default value is 1.
5483 Apply an MPlayer filter to the input video.
5485 This filter provides a wrapper around some of the filters of
5488 This wrapper is considered experimental. Some of the wrapped filters
5489 may not work properly and we may drop support for them, as they will
5490 be implemented natively into FFmpeg. Thus you should avoid
5491 depending on them when writing portable scripts.
5493 The filter accepts the parameters:
5494 @var{filter_name}[:=]@var{filter_params}
5496 @var{filter_name} is the name of a supported MPlayer filter,
5497 @var{filter_params} is a string containing the parameters accepted by
5500 The list of the currently supported filters follows:
5511 The parameter syntax and behavior for the listed filters are the same
5512 of the corresponding MPlayer filters. For detailed instructions check
5513 the "VIDEO FILTERS" section in the MPlayer manual.
5515 @subsection Examples
5519 Adjust gamma, brightness, contrast:
5525 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
5529 Drop frames that do not differ greatly from the previous frame in
5530 order to reduce frame rate.
5532 The main use of this filter is for very-low-bitrate encoding
5533 (e.g. streaming over dialup modem), but it could in theory be used for
5534 fixing movies that were inverse-telecined incorrectly.
5536 A description of the accepted options follows.
5540 Set the maximum number of consecutive frames which can be dropped (if
5541 positive), or the minimum interval between dropped frames (if
5542 negative). If the value is 0, the frame is dropped unregarding the
5543 number of previous sequentially dropped frames.
5550 Set the dropping threshold values.
5552 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
5553 represent actual pixel value differences, so a threshold of 64
5554 corresponds to 1 unit of difference for each pixel, or the same spread
5555 out differently over the block.
5557 A frame is a candidate for dropping if no 8x8 blocks differ by more
5558 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
5559 meaning the whole image) differ by more than a threshold of @option{lo}.
5561 Default value for @option{hi} is 64*12, default value for @option{lo} is
5562 64*5, and default value for @option{frac} is 0.33.
5570 This filter accepts an integer in input, if non-zero it negates the
5571 alpha component (if available). The default value in input is 0.
5575 Force libavfilter not to use any of the specified pixel formats for the
5576 input to the next filter.
5578 This filter accepts the following parameters:
5582 A '|'-separated list of pixel format names, for example
5583 "pix_fmts=yuv420p|monow|rgb24".
5587 @subsection Examples
5591 Force libavfilter to use a format different from @var{yuv420p} for the
5592 input to the vflip filter:
5594 noformat=pix_fmts=yuv420p,vflip
5598 Convert the input video to any of the formats not contained in the list:
5600 noformat=yuv420p|yuv444p|yuv410p
5606 Add noise on video input frame.
5608 The filter accepts the following options:
5616 Set noise seed for specific pixel component or all pixel components in case
5617 of @var{all_seed}. Default value is @code{123457}.
5619 @item all_strength, alls
5620 @item c0_strength, c0s
5621 @item c1_strength, c1s
5622 @item c2_strength, c2s
5623 @item c3_strength, c3s
5624 Set noise strength for specific pixel component or all pixel components in case
5625 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
5627 @item all_flags, allf
5632 Set pixel component flags or set flags for all components if @var{all_flags}.
5633 Available values for component flags are:
5636 averaged temporal noise (smoother)
5638 mix random noise with a (semi)regular pattern
5640 temporal noise (noise pattern changes between frames)
5642 uniform noise (gaussian otherwise)
5646 @subsection Examples
5648 Add temporal and uniform noise to input video:
5650 noise=alls=20:allf=t+u
5655 Pass the video source unchanged to the output.
5659 Apply video transform using libopencv.
5661 To enable this filter install libopencv library and headers and
5662 configure FFmpeg with @code{--enable-libopencv}.
5664 This filter accepts the following parameters:
5669 The name of the libopencv filter to apply.
5672 The parameters to pass to the libopencv filter. If not specified the default
5677 Refer to the official libopencv documentation for more precise
5679 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
5681 Follows the list of supported libopencv filters.
5686 Dilate an image by using a specific structuring element.
5687 This filter corresponds to the libopencv function @code{cvDilate}.
5689 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
5691 @var{struct_el} represents a structuring element, and has the syntax:
5692 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
5694 @var{cols} and @var{rows} represent the number of columns and rows of
5695 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
5696 point, and @var{shape} the shape for the structuring element, and
5697 can be one of the values "rect", "cross", "ellipse", "custom".
5699 If the value for @var{shape} is "custom", it must be followed by a
5700 string of the form "=@var{filename}". The file with name
5701 @var{filename} is assumed to represent a binary image, with each
5702 printable character corresponding to a bright pixel. When a custom
5703 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
5704 or columns and rows of the read file are assumed instead.
5706 The default value for @var{struct_el} is "3x3+0x0/rect".
5708 @var{nb_iterations} specifies the number of times the transform is
5709 applied to the image, and defaults to 1.
5711 Follow some example:
5713 # use the default values
5716 # dilate using a structuring element with a 5x5 cross, iterate two times
5717 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
5719 # read the shape from the file diamond.shape, iterate two times
5720 # the file diamond.shape may contain a pattern of characters like this:
5726 # the specified cols and rows are ignored (but not the anchor point coordinates)
5727 ocv=dilate:0x0+2x2/custom=diamond.shape|2
5732 Erode an image by using a specific structuring element.
5733 This filter corresponds to the libopencv function @code{cvErode}.
5735 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
5736 with the same syntax and semantics as the @ref{dilate} filter.
5740 Smooth the input video.
5742 The filter takes the following parameters:
5743 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
5745 @var{type} is the type of smooth filter to apply, and can be one of
5746 the following values: "blur", "blur_no_scale", "median", "gaussian",
5747 "bilateral". The default value is "gaussian".
5749 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
5750 parameters whose meanings depend on smooth type. @var{param1} and
5751 @var{param2} accept integer positive values or 0, @var{param3} and
5752 @var{param4} accept float values.
5754 The default value for @var{param1} is 3, the default value for the
5755 other parameters is 0.
5757 These parameters correspond to the parameters assigned to the
5758 libopencv function @code{cvSmooth}.
5763 Overlay one video on top of another.
5765 It takes two inputs and one output, the first input is the "main"
5766 video on which the second input is overlayed.
5768 This filter accepts the following parameters:
5770 A description of the accepted options follows.
5775 Set the expression for the x and y coordinates of the overlayed video
5776 on the main video. Default value is "0" for both expressions. In case
5777 the expression is invalid, it is set to a huge value (meaning that the
5778 overlay will not be displayed within the output visible area).
5781 Set when the expressions for @option{x}, and @option{y} are evaluated.
5783 It accepts the following values:
5786 only evaluate expressions once during the filter initialization or
5787 when a command is processed
5790 evaluate expressions for each incoming frame
5793 Default value is @samp{frame}.
5796 If set to 1, force the output to terminate when the shortest input
5797 terminates. Default value is 0.
5800 Set the format for the output video.
5802 It accepts the following values:
5814 Default value is @samp{yuv420}.
5816 @item rgb @emph{(deprecated)}
5817 If set to 1, force the filter to accept inputs in the RGB
5818 color space. Default value is 0. This option is deprecated, use
5819 @option{format} instead.
5822 If set to 1, force the filter to draw the last overlay frame over the
5823 main input until the end of the stream. A value of 0 disables this
5824 behavior. Default value is 1.
5827 The @option{x}, and @option{y} expressions can contain the following
5833 main input width and height
5837 overlay input width and height
5841 the computed values for @var{x} and @var{y}. They are evaluated for
5846 horizontal and vertical chroma subsample values of the output
5847 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
5851 the number of input frame, starting from 0
5854 the position in the file of the input frame, NAN if unknown
5857 timestamp expressed in seconds, NAN if the input timestamp is unknown
5860 Note that the @var{n}, @var{pos}, @var{t} variables are available only
5861 when evaluation is done @emph{per frame}, and will evaluate to NAN
5862 when @option{eval} is set to @samp{init}.
5864 Be aware that frames are taken from each input video in timestamp
5865 order, hence, if their initial timestamps differ, it is a good idea
5866 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
5867 have them begin in the same zero timestamp, as it does the example for
5868 the @var{movie} filter.
5870 You can chain together more overlays but you should test the
5871 efficiency of such approach.
5873 @subsection Commands
5875 This filter supports the following commands:
5879 Modify the x and y of the overlay input.
5880 The command accepts the same syntax of the corresponding option.
5882 If the specified expression is not valid, it is kept at its current
5886 @subsection Examples
5890 Draw the overlay at 10 pixels from the bottom right corner of the main
5893 overlay=main_w-overlay_w-10:main_h-overlay_h-10
5896 Using named options the example above becomes:
5898 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
5902 Insert a transparent PNG logo in the bottom left corner of the input,
5903 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
5905 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
5909 Insert 2 different transparent PNG logos (second logo on bottom
5910 right corner) using the @command{ffmpeg} tool:
5912 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
5916 Add a transparent color layer on top of the main video, @code{WxH}
5917 must specify the size of the main input to the overlay filter:
5919 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
5923 Play an original video and a filtered version (here with the deshake
5924 filter) side by side using the @command{ffplay} tool:
5926 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
5929 The above command is the same as:
5931 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
5935 Make a sliding overlay appearing from the left to the right top part of the
5936 screen starting since time 2:
5938 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
5942 Compose output by putting two input videos side to side:
5944 ffmpeg -i left.avi -i right.avi -filter_complex "
5945 nullsrc=size=200x100 [background];
5946 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
5947 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
5948 [background][left] overlay=shortest=1 [background+left];
5949 [background+left][right] overlay=shortest=1:x=100 [left+right]
5954 Chain several overlays in cascade:
5956 nullsrc=s=200x200 [bg];
5957 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
5958 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
5959 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
5960 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
5961 [in3] null, [mid2] overlay=100:100 [out0]
5968 Apply Overcomplete Wavelet denoiser.
5970 The filter accepts the following options:
5976 Larger depth values will denoise lower frequency components more, but
5977 slow down filtering.
5979 Must be an int in the range 8-16, default is @code{8}.
5981 @item luma_strength, ls
5984 Must be a double value in the range 0-1000, default is @code{1.0}.
5986 @item chroma_strength, cs
5987 Set chroma strength.
5989 Must be a double value in the range 0-1000, default is @code{1.0}.
5994 Add paddings to the input image, and place the original input at the
5995 given coordinates @var{x}, @var{y}.
5997 This filter accepts the following parameters:
6002 Specify an expression for the size of the output image with the
6003 paddings added. If the value for @var{width} or @var{height} is 0, the
6004 corresponding input size is used for the output.
6006 The @var{width} expression can reference the value set by the
6007 @var{height} expression, and vice versa.
6009 The default value of @var{width} and @var{height} is 0.
6013 Specify an expression for the offsets where to place the input image
6014 in the padded area with respect to the top/left border of the output
6017 The @var{x} expression can reference the value set by the @var{y}
6018 expression, and vice versa.
6020 The default value of @var{x} and @var{y} is 0.
6023 Specify the color of the padded area. For the syntax of this option,
6024 check the "Color" section in the ffmpeg-utils manual.
6026 The default value of @var{color} is "black".
6029 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6030 options are expressions containing the following constants:
6035 the input video width and height
6039 same as @var{in_w} and @var{in_h}
6043 the output width and height, that is the size of the padded area as
6044 specified by the @var{width} and @var{height} expressions
6048 same as @var{out_w} and @var{out_h}
6052 x and y offsets as specified by the @var{x} and @var{y}
6053 expressions, or NAN if not yet specified
6056 same as @var{iw} / @var{ih}
6059 input sample aspect ratio
6062 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6066 horizontal and vertical chroma subsample values. For example for the
6067 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6070 @subsection Examples
6074 Add paddings with color "violet" to the input video. Output video
6075 size is 640x480, the top-left corner of the input video is placed at
6078 pad=640:480:0:40:violet
6081 The example above is equivalent to the following command:
6083 pad=width=640:height=480:x=0:y=40:color=violet
6087 Pad the input to get an output with dimensions increased by 3/2,
6088 and put the input video at the center of the padded area:
6090 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6094 Pad the input to get a squared output with size equal to the maximum
6095 value between the input width and height, and put the input video at
6096 the center of the padded area:
6098 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6102 Pad the input to get a final w/h ratio of 16:9:
6104 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6108 In case of anamorphic video, in order to set the output display aspect
6109 correctly, it is necessary to use @var{sar} in the expression,
6110 according to the relation:
6112 (ih * X / ih) * sar = output_dar
6113 X = output_dar / sar
6116 Thus the previous example needs to be modified to:
6118 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6122 Double output size and put the input video in the bottom-right
6123 corner of the output padded area:
6125 pad="2*iw:2*ih:ow-iw:oh-ih"
6129 @section perspective
6131 Correct perspective of video not recorded perpendicular to the screen.
6133 A description of the accepted parameters follows.
6144 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6145 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6147 The expressions can use the following variables:
6152 the width and height of video frame.
6156 Set interpolation for perspective correction.
6158 It accepts the following values:
6164 Default value is @samp{linear}.
6169 Delay interlaced video by one field time so that the field order changes.
6171 The intended use is to fix PAL movies that have been captured with the
6172 opposite field order to the film-to-video transfer.
6174 A description of the accepted parameters follows.
6180 It accepts the following values:
6183 Capture field order top-first, transfer bottom-first.
6184 Filter will delay the bottom field.
6187 Capture field order bottom-first, transfer top-first.
6188 Filter will delay the top field.
6191 Capture and transfer with the same field order. This mode only exists
6192 for the documentation of the other options to refer to, but if you
6193 actually select it, the filter will faithfully do nothing.
6196 Capture field order determined automatically by field flags, transfer
6198 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6199 basis using field flags. If no field information is available,
6200 then this works just like @samp{u}.
6203 Capture unknown or varying, transfer opposite.
6204 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6205 analyzing the images and selecting the alternative that produces best
6206 match between the fields.
6209 Capture top-first, transfer unknown or varying.
6210 Filter selects among @samp{t} and @samp{p} using image analysis.
6213 Capture bottom-first, transfer unknown or varying.
6214 Filter selects among @samp{b} and @samp{p} using image analysis.
6217 Capture determined by field flags, transfer unknown or varying.
6218 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6219 image analysis. If no field information is available, then this works just
6220 like @samp{U}. This is the default mode.
6223 Both capture and transfer unknown or varying.
6224 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
6228 @section pixdesctest
6230 Pixel format descriptor test filter, mainly useful for internal
6231 testing. The output video should be equal to the input video.
6235 format=monow, pixdesctest
6238 can be used to test the monowhite pixel format descriptor definition.
6242 Enable the specified chain of postprocessing subfilters using libpostproc. This
6243 library should be automatically selected with a GPL build (@code{--enable-gpl}).
6244 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
6245 Each subfilter and some options have a short and a long name that can be used
6246 interchangeably, i.e. dr/dering are the same.
6248 The filters accept the following options:
6252 Set postprocessing subfilters string.
6255 All subfilters share common options to determine their scope:
6259 Honor the quality commands for this subfilter.
6262 Do chrominance filtering, too (default).
6265 Do luminance filtering only (no chrominance).
6268 Do chrominance filtering only (no luminance).
6271 These options can be appended after the subfilter name, separated by a '|'.
6273 Available subfilters are:
6276 @item hb/hdeblock[|difference[|flatness]]
6277 Horizontal deblocking filter
6280 Difference factor where higher values mean more deblocking (default: @code{32}).
6282 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6285 @item vb/vdeblock[|difference[|flatness]]
6286 Vertical deblocking filter
6289 Difference factor where higher values mean more deblocking (default: @code{32}).
6291 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6294 @item ha/hadeblock[|difference[|flatness]]
6295 Accurate horizontal deblocking filter
6298 Difference factor where higher values mean more deblocking (default: @code{32}).
6300 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6303 @item va/vadeblock[|difference[|flatness]]
6304 Accurate vertical deblocking filter
6307 Difference factor where higher values mean more deblocking (default: @code{32}).
6309 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6313 The horizontal and vertical deblocking filters share the difference and
6314 flatness values so you cannot set different horizontal and vertical
6319 Experimental horizontal deblocking filter
6322 Experimental vertical deblocking filter
6327 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
6330 larger -> stronger filtering
6332 larger -> stronger filtering
6334 larger -> stronger filtering
6337 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
6340 Stretch luminance to @code{0-255}.
6343 @item lb/linblenddeint
6344 Linear blend deinterlacing filter that deinterlaces the given block by
6345 filtering all lines with a @code{(1 2 1)} filter.
6347 @item li/linipoldeint
6348 Linear interpolating deinterlacing filter that deinterlaces the given block by
6349 linearly interpolating every second line.
6351 @item ci/cubicipoldeint
6352 Cubic interpolating deinterlacing filter deinterlaces the given block by
6353 cubically interpolating every second line.
6355 @item md/mediandeint
6356 Median deinterlacing filter that deinterlaces the given block by applying a
6357 median filter to every second line.
6359 @item fd/ffmpegdeint
6360 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
6361 second line with a @code{(-1 4 2 4 -1)} filter.
6364 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
6365 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
6367 @item fq/forceQuant[|quantizer]
6368 Overrides the quantizer table from the input with the constant quantizer you
6376 Default pp filter combination (@code{hb|a,vb|a,dr|a})
6379 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
6382 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
6385 @subsection Examples
6389 Apply horizontal and vertical deblocking, deringing and automatic
6390 brightness/contrast:
6396 Apply default filters without brightness/contrast correction:
6402 Apply default filters and temporal denoiser:
6404 pp=default/tmpnoise|1|2|3
6408 Apply deblocking on luminance only, and switch vertical deblocking on or off
6409 automatically depending on available CPU time:
6417 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
6418 Ratio) between two input videos.
6420 This filter takes in input two input videos, the first input is
6421 considered the "main" source and is passed unchanged to the
6422 output. The second input is used as a "reference" video for computing
6425 Both video inputs must have the same resolution and pixel format for
6426 this filter to work correctly. Also it assumes that both inputs
6427 have the same number of frames, which are compared one by one.
6429 The obtained average PSNR is printed through the logging system.
6431 The filter stores the accumulated MSE (mean squared error) of each
6432 frame, and at the end of the processing it is averaged across all frames
6433 equally, and the following formula is applied to obtain the PSNR:
6436 PSNR = 10*log10(MAX^2/MSE)
6439 Where MAX is the average of the maximum values of each component of the
6442 The description of the accepted parameters follows.
6446 If specified the filter will use the named file to save the PSNR of
6447 each individual frame.
6450 The file printed if @var{stats_file} is selected, contains a sequence of
6451 key/value pairs of the form @var{key}:@var{value} for each compared
6454 A description of each shown parameter follows:
6458 sequential number of the input frame, starting from 1
6461 Mean Square Error pixel-by-pixel average difference of the compared
6462 frames, averaged over all the image components.
6464 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
6465 Mean Square Error pixel-by-pixel average difference of the compared
6466 frames for the component specified by the suffix.
6468 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
6469 Peak Signal to Noise ratio of the compared frames for the component
6470 specified by the suffix.
6475 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
6476 [main][ref] psnr="stats_file=stats.log" [out]
6479 On this example the input file being processed is compared with the
6480 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
6481 is stored in @file{stats.log}.
6485 Pulldown reversal (inverse telecine) filter, capable of handling mixed
6486 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
6489 The pullup filter is designed to take advantage of future context in making
6490 its decisions. This filter is stateless in the sense that it does not lock
6491 onto a pattern to follow, but it instead looks forward to the following
6492 fields in order to identify matches and rebuild progressive frames.
6494 To produce content with an even framerate, insert the fps filter after
6495 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
6496 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
6498 The filter accepts the following options:
6505 These options set the amount of "junk" to ignore at the left, right, top, and
6506 bottom of the image, respectively. Left and right are in units of 8 pixels,
6507 while top and bottom are in units of 2 lines.
6508 The default is 8 pixels on each side.
6511 Set the strict breaks. Setting this option to 1 will reduce the chances of
6512 filter generating an occasional mismatched frame, but it may also cause an
6513 excessive number of frames to be dropped during high motion sequences.
6514 Conversely, setting it to -1 will make filter match fields more easily.
6515 This may help processing of video where there is slight blurring between
6516 the fields, but may also cause there to be interlaced frames in the output.
6517 Default value is @code{0}.
6520 Set the metric plane to use. It accepts the following values:
6526 Use chroma blue plane.
6529 Use chroma red plane.
6532 This option may be set to use chroma plane instead of the default luma plane
6533 for doing filter's computations. This may improve accuracy on very clean
6534 source material, but more likely will decrease accuracy, especially if there
6535 is chroma noise (rainbow effect) or any grayscale video.
6536 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
6537 load and make pullup usable in realtime on slow machines.
6540 For best results (without duplicated frames in the output file) it is
6541 necessary to change the output frame rate. For example, to inverse
6542 telecine NTSC input:
6544 ffmpeg -i input -vf pullup -r 24000/1001 ...
6549 Suppress a TV station logo, using an image file to determine which
6550 pixels comprise the logo. It works by filling in the pixels that
6551 comprise the logo with neighboring pixels.
6553 The filter accepts the following options:
6557 Set the filter bitmap file, which can be any image format supported by
6558 libavformat. The width and height of the image file must match those of the
6559 video stream being processed.
6562 Pixels in the provided bitmap image with a value of zero are not
6563 considered part of the logo, non-zero pixels are considered part of
6564 the logo. If you use white (255) for the logo and black (0) for the
6565 rest, you will be safe. For making the filter bitmap, it is
6566 recommended to take a screen capture of a black frame with the logo
6567 visible, and then using a threshold filter followed by the erode
6568 filter once or twice.
6570 If needed, little splotches can be fixed manually. Remember that if
6571 logo pixels are not covered, the filter quality will be much
6572 reduced. Marking too many pixels as part of the logo does not hurt as
6573 much, but it will increase the amount of blurring needed to cover over
6574 the image and will destroy more information than necessary, and extra
6575 pixels will slow things down on a large logo.
6579 Rotate video by an arbitrary angle expressed in radians.
6581 The filter accepts the following options:
6583 A description of the optional parameters follows.
6586 Set an expression for the angle by which to rotate the input video
6587 clockwise, expressed as a number of radians. A negative value will
6588 result in a counter-clockwise rotation. By default it is set to "0".
6590 This expression is evaluated for each frame.
6593 Set the output width expression, default value is "iw".
6594 This expression is evaluated just once during configuration.
6597 Set the output height expression, default value is "ih".
6598 This expression is evaluated just once during configuration.
6601 Enable bilinear interpolation if set to 1, a value of 0 disables
6602 it. Default value is 1.
6605 Set the color used to fill the output area not covered by the rotated
6606 image. For the generalsyntax of this option, check the "Color" section in the
6607 ffmpeg-utils manual. If the special value "none" is selected then no
6608 background is printed (useful for example if the background is never shown).
6610 Default value is "black".
6613 The expressions for the angle and the output size can contain the
6614 following constants and functions:
6618 sequential number of the input frame, starting from 0. It is always NAN
6619 before the first frame is filtered.
6622 time in seconds of the input frame, it is set to 0 when the filter is
6623 configured. It is always NAN before the first frame is filtered.
6627 horizontal and vertical chroma subsample values. For example for the
6628 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6632 the input video width and heigth
6636 the output width and heigth, that is the size of the padded area as
6637 specified by the @var{width} and @var{height} expressions
6641 the minimal width/height required for completely containing the input
6642 video rotated by @var{a} radians.
6644 These are only available when computing the @option{out_w} and
6645 @option{out_h} expressions.
6648 @subsection Examples
6652 Rotate the input by PI/6 radians clockwise:
6658 Rotate the input by PI/6 radians counter-clockwise:
6664 Apply a constant rotation with period T, starting from an angle of PI/3:
6666 rotate=PI/3+2*PI*t/T
6670 Make the input video rotation oscillating with a period of T
6671 seconds and an amplitude of A radians:
6673 rotate=A*sin(2*PI/T*t)
6677 Rotate the video, output size is choosen so that the whole rotating
6678 input video is always completely contained in the output:
6680 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
6684 Rotate the video, reduce the output size so that no background is ever
6687 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
6691 @subsection Commands
6693 The filter supports the following commands:
6697 Set the angle expression.
6698 The command accepts the same syntax of the corresponding option.
6700 If the specified expression is not valid, it is kept at its current
6706 Apply Shape Adaptive Blur.
6708 The filter accepts the following options:
6711 @item luma_radius, lr
6712 Set luma blur filter strength, must be a value in range 0.1-4.0, default
6713 value is 1.0. A greater value will result in a more blurred image, and
6714 in slower processing.
6716 @item luma_pre_filter_radius, lpfr
6717 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
6720 @item luma_strength, ls
6721 Set luma maximum difference between pixels to still be considered, must
6722 be a value in the 0.1-100.0 range, default value is 1.0.
6724 @item chroma_radius, cr
6725 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
6726 greater value will result in a more blurred image, and in slower
6729 @item chroma_pre_filter_radius, cpfr
6730 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
6732 @item chroma_strength, cs
6733 Set chroma maximum difference between pixels to still be considered,
6734 must be a value in the 0.1-100.0 range.
6737 Each chroma option value, if not explicitly specified, is set to the
6738 corresponding luma option value.
6743 Scale (resize) the input video, using the libswscale library.
6745 The scale filter forces the output display aspect ratio to be the same
6746 of the input, by changing the output sample aspect ratio.
6748 If the input image format is different from the format requested by
6749 the next filter, the scale filter will convert the input to the
6753 The filter accepts the following options, or any of the options
6754 supported by the libswscale scaler.
6756 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
6757 the complete list of scaler options.
6762 Set the output video dimension expression. Default value is the input
6765 If the value is 0, the input width is used for the output.
6767 If one of the values is -1, the scale filter will use a value that
6768 maintains the aspect ratio of the input image, calculated from the
6769 other specified dimension. If both of them are -1, the input size is
6772 See below for the list of accepted constants for use in the dimension
6776 Set the interlacing mode. It accepts the following values:
6780 Force interlaced aware scaling.
6783 Do not apply interlaced scaling.
6786 Select interlaced aware scaling depending on whether the source frames
6787 are flagged as interlaced or not.
6790 Default value is @samp{0}.
6793 Set libswscale scaling flags. See
6794 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
6795 complete list of values. If not explictly specified the filter applies
6799 Set the video size. For the syntax of this option, check the "Video size"
6800 section in the ffmpeg-utils manual.
6802 @item in_color_matrix
6803 @item out_color_matrix
6804 Set in/output YCbCr color space type.
6806 This allows the autodetected value to be overridden as well as allows forcing
6807 a specific value used for the output and encoder.
6809 If not specified, the color space type depends on the pixel format.
6815 Choose automatically.
6818 Format conforming to International Telecommunication Union (ITU)
6819 Recommendation BT.709.
6822 Set color space conforming to the United States Federal Communications
6823 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
6826 Set color space conforming to:
6830 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
6833 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
6836 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
6841 Set color space conforming to SMPTE ST 240:1999.
6846 Set in/output YCbCr sample range.
6848 This allows the autodetected value to be overridden as well as allows forcing
6849 a specific value used for the output and encoder. If not specified, the
6850 range depends on the pixel format. Possible values:
6854 Choose automatically.
6857 Set full range (0-255 in case of 8-bit luma).
6860 Set "MPEG" range (16-235 in case of 8-bit luma).
6863 @item force_original_aspect_ratio
6864 Enable decreasing or increasing output video width or height if necessary to
6865 keep the original aspect ratio. Possible values:
6869 Scale the video as specified and disable this feature.
6872 The output video dimensions will automatically be decreased if needed.
6875 The output video dimensions will automatically be increased if needed.
6879 One useful instance of this option is that when you know a specific device's
6880 maximum allowed resolution, you can use this to limit the output video to
6881 that, while retaining the aspect ratio. For example, device A allows
6882 1280x720 playback, and your video is 1920x800. Using this option (set it to
6883 decrease) and specifying 1280x720 to the command line makes the output
6886 Please note that this is a different thing than specifying -1 for @option{w}
6887 or @option{h}, you still need to specify the output resolution for this option
6892 The values of the @option{w} and @option{h} options are expressions
6893 containing the following constants:
6898 the input width and height
6902 same as @var{in_w} and @var{in_h}
6906 the output (scaled) width and height
6910 same as @var{out_w} and @var{out_h}
6913 same as @var{iw} / @var{ih}
6916 input sample aspect ratio
6919 input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
6923 horizontal and vertical input chroma subsample values. For example for the
6924 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6928 horizontal and vertical output chroma subsample values. For example for the
6929 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6932 @subsection Examples
6936 Scale the input video to a size of 200x100:
6941 This is equivalent to:
6952 Specify a size abbreviation for the output size:
6957 which can also be written as:
6963 Scale the input to 2x:
6969 The above is the same as:
6975 Scale the input to 2x with forced interlaced scaling:
6977 scale=2*iw:2*ih:interl=1
6981 Scale the input to half size:
6987 Increase the width, and set the height to the same size:
6993 Seek for Greek harmony:
7000 Increase the height, and set the width to 3/2 of the height:
7002 scale=w=3/2*oh:h=3/5*ih
7006 Increase the size, but make the size a multiple of the chroma
7009 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7013 Increase the width to a maximum of 500 pixels, keep the same input
7016 scale=w='min(500\, iw*3/2):h=-1'
7020 @section separatefields
7022 The @code{separatefields} takes a frame-based video input and splits
7023 each frame into its components fields, producing a new half height clip
7024 with twice the frame rate and twice the frame count.
7026 This filter use field-dominance information in frame to decide which
7027 of each pair of fields to place first in the output.
7028 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7030 @section setdar, setsar
7032 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7035 This is done by changing the specified Sample (aka Pixel) Aspect
7036 Ratio, according to the following equation:
7038 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7041 Keep in mind that the @code{setdar} filter does not modify the pixel
7042 dimensions of the video frame. Also the display aspect ratio set by
7043 this filter may be changed by later filters in the filterchain,
7044 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7047 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7048 the filter output video.
7050 Note that as a consequence of the application of this filter, the
7051 output display aspect ratio will change according to the equation
7054 Keep in mind that the sample aspect ratio set by the @code{setsar}
7055 filter may be changed by later filters in the filterchain, e.g. if
7056 another "setsar" or a "setdar" filter is applied.
7058 The filters accept the following options:
7061 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7062 Set the aspect ratio used by the filter.
7064 The parameter can be a floating point number string, an expression, or
7065 a string of the form @var{num}:@var{den}, where @var{num} and
7066 @var{den} are the numerator and denominator of the aspect ratio. If
7067 the parameter is not specified, it is assumed the value "0".
7068 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7072 Set the maximum integer value to use for expressing numerator and
7073 denominator when reducing the expressed aspect ratio to a rational.
7074 Default value is @code{100}.
7078 The parameter @var{sar} is an expression containing
7079 the following constants:
7083 the corresponding mathematical approximated values for e
7084 (euler number), pi (greek PI), phi (golden ratio)
7087 the input width and height
7090 same as @var{w} / @var{h}
7093 input sample aspect ratio
7096 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
7099 horizontal and vertical chroma subsample values. For example for the
7100 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7103 @subsection Examples
7108 To change the display aspect ratio to 16:9, specify one of the following:
7116 To change the sample aspect ratio to 10:11, specify:
7122 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7123 1000 in the aspect ratio reduction, use the command:
7125 setdar=ratio=16/9:max=1000
7133 Force field for the output video frame.
7135 The @code{setfield} filter marks the interlace type field for the
7136 output frames. It does not change the input frame, but only sets the
7137 corresponding property, which affects how the frame is treated by
7138 following filters (e.g. @code{fieldorder} or @code{yadif}).
7140 The filter accepts the following options:
7145 Available values are:
7149 Keep the same field property.
7152 Mark the frame as bottom-field-first.
7155 Mark the frame as top-field-first.
7158 Mark the frame as progressive.
7164 Show a line containing various information for each input video frame.
7165 The input video is not modified.
7167 The shown line contains a sequence of key/value pairs of the form
7168 @var{key}:@var{value}.
7170 A description of each shown parameter follows:
7174 sequential number of the input frame, starting from 0
7177 Presentation TimeStamp of the input frame, expressed as a number of
7178 time base units. The time base unit depends on the filter input pad.
7181 Presentation TimeStamp of the input frame, expressed as a number of
7185 position of the frame in the input stream, -1 if this information in
7186 unavailable and/or meaningless (for example in case of synthetic video)
7192 sample aspect ratio of the input frame, expressed in the form
7196 size of the input frame. For the syntax of this option, check the "Video size"
7197 section in the ffmpeg-utils manual.
7200 interlaced mode ("P" for "progressive", "T" for top field first, "B"
7201 for bottom field first)
7204 1 if the frame is a key frame, 0 otherwise
7207 picture type of the input frame ("I" for an I-frame, "P" for a
7208 P-frame, "B" for a B-frame, "?" for unknown type).
7209 Check also the documentation of the @code{AVPictureType} enum and of
7210 the @code{av_get_picture_type_char} function defined in
7211 @file{libavutil/avutil.h}.
7214 Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame
7216 @item plane_checksum
7217 Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
7218 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]"
7224 Blur the input video without impacting the outlines.
7226 The filter accepts the following options:
7229 @item luma_radius, lr
7230 Set the luma radius. The option value must be a float number in
7231 the range [0.1,5.0] that specifies the variance of the gaussian filter
7232 used to blur the image (slower if larger). Default value is 1.0.
7234 @item luma_strength, ls
7235 Set the luma strength. The option value must be a float number
7236 in the range [-1.0,1.0] that configures the blurring. A value included
7237 in [0.0,1.0] will blur the image whereas a value included in
7238 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7240 @item luma_threshold, lt
7241 Set the luma threshold used as a coefficient to determine
7242 whether a pixel should be blurred or not. The option value must be an
7243 integer in the range [-30,30]. A value of 0 will filter all the image,
7244 a value included in [0,30] will filter flat areas and a value included
7245 in [-30,0] will filter edges. Default value is 0.
7247 @item chroma_radius, cr
7248 Set the chroma radius. The option value must be a float number in
7249 the range [0.1,5.0] that specifies the variance of the gaussian filter
7250 used to blur the image (slower if larger). Default value is 1.0.
7252 @item chroma_strength, cs
7253 Set the chroma strength. The option value must be a float number
7254 in the range [-1.0,1.0] that configures the blurring. A value included
7255 in [0.0,1.0] will blur the image whereas a value included in
7256 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7258 @item chroma_threshold, ct
7259 Set the chroma threshold used as a coefficient to determine
7260 whether a pixel should be blurred or not. The option value must be an
7261 integer in the range [-30,30]. A value of 0 will filter all the image,
7262 a value included in [0,30] will filter flat areas and a value included
7263 in [-30,0] will filter edges. Default value is 0.
7266 If a chroma option is not explicitly set, the corresponding luma value
7271 Convert between different stereoscopic image formats.
7273 The filters accept the following options:
7277 Set stereoscopic image format of input.
7279 Available values for input image formats are:
7282 side by side parallel (left eye left, right eye right)
7285 side by side crosseye (right eye left, left eye right)
7288 side by side parallel with half width resolution
7289 (left eye left, right eye right)
7292 side by side crosseye with half width resolution
7293 (right eye left, left eye right)
7296 above-below (left eye above, right eye below)
7299 above-below (right eye above, left eye below)
7302 above-below with half height resolution
7303 (left eye above, right eye below)
7306 above-below with half height resolution
7307 (right eye above, left eye below)
7310 alternating frames (left eye first, right eye second)
7313 alternating frames (right eye first, left eye second)
7315 Default value is @samp{sbsl}.
7319 Set stereoscopic image format of output.
7321 Available values for output image formats are all the input formats as well as:
7324 anaglyph red/blue gray
7325 (red filter on left eye, blue filter on right eye)
7328 anaglyph red/green gray
7329 (red filter on left eye, green filter on right eye)
7332 anaglyph red/cyan gray
7333 (red filter on left eye, cyan filter on right eye)
7336 anaglyph red/cyan half colored
7337 (red filter on left eye, cyan filter on right eye)
7340 anaglyph red/cyan color
7341 (red filter on left eye, cyan filter on right eye)
7344 anaglyph red/cyan color optimized with the least squares projection of dubois
7345 (red filter on left eye, cyan filter on right eye)
7348 anaglyph green/magenta gray
7349 (green filter on left eye, magenta filter on right eye)
7352 anaglyph green/magenta half colored
7353 (green filter on left eye, magenta filter on right eye)
7356 anaglyph green/magenta colored
7357 (green filter on left eye, magenta filter on right eye)
7360 anaglyph green/magenta color optimized with the least squares projection of dubois
7361 (green filter on left eye, magenta filter on right eye)
7364 anaglyph yellow/blue gray
7365 (yellow filter on left eye, blue filter on right eye)
7368 anaglyph yellow/blue half colored
7369 (yellow filter on left eye, blue filter on right eye)
7372 anaglyph yellow/blue colored
7373 (yellow filter on left eye, blue filter on right eye)
7376 anaglyph yellow/blue color optimized with the least squares projection of dubois
7377 (yellow filter on left eye, blue filter on right eye)
7380 interleaved rows (left eye has top row, right eye starts on next row)
7383 interleaved rows (right eye has top row, left eye starts on next row)
7386 mono output (left eye only)
7389 mono output (right eye only)
7392 Default value is @samp{arcd}.
7395 @subsection Examples
7399 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
7405 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
7413 Apply a simple postprocessing filter that compresses and decompresses the image
7414 at several (or - in the case of @option{quality} level @code{6} - all) shifts
7415 and average the results.
7417 The filter accepts the following options:
7421 Set quality. This option defines the number of levels for averaging. It accepts
7422 an integer in the range 0-6. If set to @code{0}, the filter will have no
7423 effect. A value of @code{6} means the higher quality. For each increment of
7424 that value the speed drops by a factor of approximately 2. Default value is
7428 Force a constant quantization parameter. If not set, the filter will use the QP
7429 from the video stream (if available).
7432 Set thresholding mode. Available modes are:
7436 Set hard thresholding (default).
7438 Set soft thresholding (better de-ringing effect, but likely blurrier).
7442 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
7443 option may cause flicker since the B-Frames have often larger QP. Default is
7444 @code{0} (not enabled).
7450 Draw subtitles on top of input video using the libass library.
7452 To enable compilation of this filter you need to configure FFmpeg with
7453 @code{--enable-libass}. This filter also requires a build with libavcodec and
7454 libavformat to convert the passed subtitles file to ASS (Advanced Substation
7455 Alpha) subtitles format.
7457 The filter accepts the following options:
7461 Set the filename of the subtitle file to read. It must be specified.
7464 Specify the size of the original video, the video for which the ASS file
7465 was composed. For the syntax of this option, check the "Video size" section in
7466 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
7467 this is necessary to correctly scale the fonts if the aspect ratio has been
7471 Set subtitles input character encoding. @code{subtitles} filter only. Only
7472 useful if not UTF-8.
7475 If the first key is not specified, it is assumed that the first value
7476 specifies the @option{filename}.
7478 For example, to render the file @file{sub.srt} on top of the input
7479 video, use the command:
7484 which is equivalent to:
7486 subtitles=filename=sub.srt
7491 Scale the input by 2x and smooth using the Super2xSaI (Scale and
7492 Interpolate) pixel art scaling algorithm.
7494 Useful for enlarging pixel art images without reducing sharpness.
7501 Apply telecine process to the video.
7503 This filter accepts the following options:
7512 The default value is @code{top}.
7516 A string of numbers representing the pulldown pattern you wish to apply.
7517 The default value is @code{23}.
7521 Some typical patterns:
7526 24p: 2332 (preferred)
7533 24p: 222222222223 ("Euro pulldown")
7539 Select the most representative frame in a given sequence of consecutive frames.
7541 The filter accepts the following options:
7545 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
7546 will pick one of them, and then handle the next batch of @var{n} frames until
7547 the end. Default is @code{100}.
7550 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
7551 value will result in a higher memory usage, so a high value is not recommended.
7553 @subsection Examples
7557 Extract one picture each 50 frames:
7563 Complete example of a thumbnail creation with @command{ffmpeg}:
7565 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
7571 Tile several successive frames together.
7573 The filter accepts the following options:
7578 Set the grid size (i.e. the number of lines and columns). For the syntax of
7579 this option, check the "Video size" section in the ffmpeg-utils manual.
7582 Set the maximum number of frames to render in the given area. It must be less
7583 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
7584 the area will be used.
7587 Set the outer border margin in pixels.
7590 Set the inner border thickness (i.e. the number of pixels between frames). For
7591 more advanced padding options (such as having different values for the edges),
7592 refer to the pad video filter.
7595 Specify the color of the unused areaFor the syntax of this option, check the
7596 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
7600 @subsection Examples
7604 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
7606 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
7608 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
7609 duplicating each output frame to accomodate the originally detected frame
7613 Display @code{5} pictures in an area of @code{3x2} frames,
7614 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
7615 mixed flat and named options:
7617 tile=3x2:nb_frames=5:padding=7:margin=2
7623 Perform various types of temporal field interlacing.
7625 Frames are counted starting from 1, so the first input frame is
7628 The filter accepts the following options:
7633 Specify the mode of the interlacing. This option can also be specified
7634 as a value alone. See below for a list of values for this option.
7636 Available values are:
7640 Move odd frames into the upper field, even into the lower field,
7641 generating a double height frame at half frame rate.
7644 Only output even frames, odd frames are dropped, generating a frame with
7645 unchanged height at half frame rate.
7648 Only output odd frames, even frames are dropped, generating a frame with
7649 unchanged height at half frame rate.
7652 Expand each frame to full height, but pad alternate lines with black,
7653 generating a frame with double height at the same input frame rate.
7655 @item interleave_top, 4
7656 Interleave the upper field from odd frames with the lower field from
7657 even frames, generating a frame with unchanged height at half frame rate.
7659 @item interleave_bottom, 5
7660 Interleave the lower field from odd frames with the upper field from
7661 even frames, generating a frame with unchanged height at half frame rate.
7663 @item interlacex2, 6
7664 Double frame rate with unchanged height. Frames are inserted each
7665 containing the second temporal field from the previous input frame and
7666 the first temporal field from the next input frame. This mode relies on
7667 the top_field_first flag. Useful for interlaced video displays with no
7668 field synchronisation.
7671 Numeric values are deprecated but are accepted for backward
7672 compatibility reasons.
7674 Default mode is @code{merge}.
7677 Specify flags influencing the filter process.
7679 Available value for @var{flags} is:
7682 @item low_pass_filter, vlfp
7683 Enable vertical low-pass filtering in the filter.
7684 Vertical low-pass filtering is required when creating an interlaced
7685 destination from a progressive source which contains high-frequency
7686 vertical detail. Filtering will reduce interlace 'twitter' and Moire
7689 Vertical low-pass filtering can only be enabled for @option{mode}
7690 @var{interleave_top} and @var{interleave_bottom}.
7697 Transpose rows with columns in the input video and optionally flip it.
7699 This filter accepts the following options:
7704 Specify the transposition direction.
7706 Can assume the following values:
7708 @item 0, 4, cclock_flip
7709 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
7717 Rotate by 90 degrees clockwise, that is:
7725 Rotate by 90 degrees counterclockwise, that is:
7732 @item 3, 7, clock_flip
7733 Rotate by 90 degrees clockwise and vertically flip, that is:
7741 For values between 4-7, the transposition is only done if the input
7742 video geometry is portrait and not landscape. These values are
7743 deprecated, the @code{passthrough} option should be used instead.
7745 Numerical values are deprecated, and should be dropped in favor of
7749 Do not apply the transposition if the input geometry matches the one
7750 specified by the specified value. It accepts the following values:
7753 Always apply transposition.
7755 Preserve portrait geometry (when @var{height} >= @var{width}).
7757 Preserve landscape geometry (when @var{width} >= @var{height}).
7760 Default value is @code{none}.
7763 For example to rotate by 90 degrees clockwise and preserve portrait
7766 transpose=dir=1:passthrough=portrait
7769 The command above can also be specified as:
7771 transpose=1:portrait
7775 Trim the input so that the output contains one continuous subpart of the input.
7777 This filter accepts the following options:
7780 Specify time of the start of the kept section, i.e. the frame with the
7781 timestamp @var{start} will be the first frame in the output.
7784 Specify time of the first frame that will be dropped, i.e. the frame
7785 immediately preceding the one with the timestamp @var{end} will be the last
7786 frame in the output.
7789 Same as @var{start}, except this option sets the start timestamp in timebase
7790 units instead of seconds.
7793 Same as @var{end}, except this option sets the end timestamp in timebase units
7797 Specify maximum duration of the output.
7800 Number of the first frame that should be passed to output.
7803 Number of the first frame that should be dropped.
7806 @option{start}, @option{end}, @option{duration} are expressed as time
7807 duration specifications, check the "Time duration" section in the
7808 ffmpeg-utils manual.
7810 Note that the first two sets of the start/end options and the @option{duration}
7811 option look at the frame timestamp, while the _frame variants simply count the
7812 frames that pass through the filter. Also note that this filter does not modify
7813 the timestamps. If you wish that the output timestamps start at zero, insert a
7814 setpts filter after the trim filter.
7816 If multiple start or end options are set, this filter tries to be greedy and
7817 keep all the frames that match at least one of the specified constraints. To keep
7818 only the part that matches all the constraints at once, chain multiple trim
7821 The defaults are such that all the input is kept. So it is possible to set e.g.
7822 just the end values to keep everything before the specified time.
7827 drop everything except the second minute of input
7829 ffmpeg -i INPUT -vf trim=60:120
7833 keep only the first second
7835 ffmpeg -i INPUT -vf trim=duration=1
7843 Sharpen or blur the input video.
7845 It accepts the following parameters:
7848 @item luma_msize_x, lx
7849 Set the luma matrix horizontal size. It must be an odd integer between
7850 3 and 63, default value is 5.
7852 @item luma_msize_y, ly
7853 Set the luma matrix vertical size. It must be an odd integer between 3
7854 and 63, default value is 5.
7856 @item luma_amount, la
7857 Set the luma effect strength. It can be a float number, reasonable
7858 values lay between -1.5 and 1.5.
7860 Negative values will blur the input video, while positive values will
7861 sharpen it, a value of zero will disable the effect.
7863 Default value is 1.0.
7865 @item chroma_msize_x, cx
7866 Set the chroma matrix horizontal size. It must be an odd integer
7867 between 3 and 63, default value is 5.
7869 @item chroma_msize_y, cy
7870 Set the chroma matrix vertical size. It must be an odd integer
7871 between 3 and 63, default value is 5.
7873 @item chroma_amount, ca
7874 Set the chroma effect strength. It can be a float number, reasonable
7875 values lay between -1.5 and 1.5.
7877 Negative values will blur the input video, while positive values will
7878 sharpen it, a value of zero will disable the effect.
7880 Default value is 0.0.
7883 If set to 1, specify using OpenCL capabilities, only available if
7884 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
7888 All parameters are optional and default to the equivalent of the
7889 string '5:5:1.0:5:5:0.0'.
7891 @subsection Examples
7895 Apply strong luma sharpen effect:
7897 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
7901 Apply strong blur of both luma and chroma parameters:
7903 unsharp=7:7:-2:7:7:-2
7907 @anchor{vidstabdetect}
7908 @section vidstabdetect
7910 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
7911 @ref{vidstabtransform} for pass 2.
7913 This filter generates a file with relative translation and rotation
7914 transform information about subsequent frames, which is then used by
7915 the @ref{vidstabtransform} filter.
7917 To enable compilation of this filter you need to configure FFmpeg with
7918 @code{--enable-libvidstab}.
7920 This filter accepts the following options:
7924 Set the path to the file used to write the transforms information.
7925 Default value is @file{transforms.trf}.
7928 Set how shaky the video is and how quick the camera is. It accepts an
7929 integer in the range 1-10, a value of 1 means little shakiness, a
7930 value of 10 means strong shakiness. Default value is 5.
7933 Set the accuracy of the detection process. It must be a value in the
7934 range 1-15. A value of 1 means low accuracy, a value of 15 means high
7935 accuracy. Default value is 9.
7938 Set stepsize of the search process. The region around minimum is
7939 scanned with 1 pixel resolution. Default value is 6.
7942 Set minimum contrast. Below this value a local measurement field is
7943 discarded. Must be a floating point value in the range 0-1. Default
7947 Set reference frame number for tripod mode.
7949 If enabled, the motion of the frames is compared to a reference frame
7950 in the filtered stream, identified by the specified number. The idea
7951 is to compensate all movements in a more-or-less static scene and keep
7952 the camera view absolutely still.
7954 If set to 0, it is disabled. The frames are counted starting from 1.
7957 Show fields and transforms in the resulting frames. It accepts an
7958 integer in the range 0-2. Default value is 0, which disables any
7962 @subsection Examples
7972 Analyze strongly shaky movie and put the results in file
7973 @file{mytransforms.trf}:
7975 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
7979 Visualize the result of internal transformations in the resulting
7982 vidstabdetect=show=1
7986 Analyze a video with medium shakiness using @command{ffmpeg}:
7988 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
7992 @anchor{vidstabtransform}
7993 @section vidstabtransform
7995 Video stabilization/deshaking: pass 2 of 2,
7996 see @ref{vidstabdetect} for pass 1.
7998 Read a file with transform information for each frame and
7999 apply/compensate them. Together with the @ref{vidstabdetect}
8000 filter this can be used to deshake videos. See also
8001 @url{http://public.hronopik.de/vid.stab}. It is important to also use
8002 the unsharp filter, see below.
8004 To enable compilation of this filter you need to configure FFmpeg with
8005 @code{--enable-libvidstab}.
8007 This filter accepts the following options:
8012 path to the file used to read the transforms (default: @file{transforms.trf})
8015 number of frames (value*2 + 1) used for lowpass filtering the camera movements
8016 (default: 10). For example a number of 10 means that 21 frames are used
8017 (10 in the past and 10 in the future) to smoothen the motion in the
8018 video. A larger values leads to a smoother video, but limits the
8019 acceleration of the camera (pan/tilt movements).
8022 maximal number of pixels to translate frames (default: -1 no limit)
8025 maximal angle in radians (degree*PI/180) to rotate frames (default: -1
8029 How to deal with borders that may be visible due to movement
8030 compensation. Available values are:
8034 keep image information from previous frame (default)
8036 fill the border black
8042 keep transforms normal (default)
8048 consider transforms as
8053 relative to previous frame (default)
8057 percentage to zoom (default: 0)
8066 set optimal zooming to avoid borders
8071 optimal static zoom value is determined (only very strong movements will lead to visible borders) (default)
8073 optimal adaptive zoom value is determined (no borders will be visible)
8075 Note that the value given at zoom is added to the one calculated
8079 type of interpolation
8081 Available values are:
8086 linear only horizontal
8088 linear in both directions (default)
8090 cubic in both directions (slow)
8094 virtual tripod mode means that the video is stabilized such that the
8095 camera stays stationary. Use also @code{tripod} option of
8096 @ref{vidstabdetect}.
8101 virtual tripod mode: equivalent to @code{relative=0:smoothing=0}
8106 @subsection Examples
8110 typical call with default default values:
8111 (note the unsharp filter which is always recommended)
8113 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
8117 zoom in a bit more and load transform data from a given file
8119 vidstabtransform=zoom=5:input="mytransforms.trf"
8123 smoothen the video even more
8125 vidstabtransform=smoothing=30
8132 Flip the input video vertically.
8134 For example, to vertically flip a video with @command{ffmpeg}:
8136 ffmpeg -i in.avi -vf "vflip" out.avi
8141 Make or reverse a natural vignetting effect.
8143 The filter accepts the following options:
8147 Set lens angle expression as a number of radians.
8149 The value is clipped in the @code{[0,PI/2]} range.
8151 Default value: @code{"PI/5"}
8155 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
8159 Set forward/backward mode.
8161 Available modes are:
8164 The larger the distance from the central point, the darker the image becomes.
8167 The larger the distance from the central point, the brighter the image becomes.
8168 This can be used to reverse a vignette effect, though there is no automatic
8169 detection to extract the lens @option{angle} and other settings (yet). It can
8170 also be used to create a burning effect.
8173 Default value is @samp{forward}.
8176 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
8178 It accepts the following values:
8181 Evaluate expressions only once during the filter initialization.
8184 Evaluate expressions for each incoming frame. This is way slower than the
8185 @samp{init} mode since it requires all the scalers to be re-computed, but it
8186 allows advanced dynamic expressions.
8189 Default value is @samp{init}.
8192 Set dithering to reduce the circular banding effects. Default is @code{1}
8196 Set vignette aspect. This setting allows to adjust the shape of the vignette.
8197 Setting this value to the SAR of the input will make a rectangular vignetting
8198 following the dimensions of the video.
8200 Default is @code{1/1}.
8203 @subsection Expressions
8205 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
8206 following parameters.
8211 input width and height
8214 the number of input frame, starting from 0
8217 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
8218 @var{TB} units, NAN if undefined
8221 frame rate of the input video, NAN if the input frame rate is unknown
8224 the PTS (Presentation TimeStamp) of the filtered video frame,
8225 expressed in seconds, NAN if undefined
8228 time base of the input video
8232 @subsection Examples
8236 Apply simple strong vignetting effect:
8242 Make a flickering vignetting:
8244 vignette='PI/4+random(1)*PI/50':eval=frame
8251 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
8252 Deinterlacing Filter").
8254 Based on the process described by Martin Weston for BBC R&D, and
8255 implemented based on the de-interlace algorithm written by Jim
8256 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
8257 uses filter coefficients calculated by BBC R&D.
8259 There are two sets of filter coefficients, so called "simple":
8260 and "complex". Which set of filter coefficients is used can
8261 be set by passing an optional parameter:
8265 Set the interlacing filter coefficients. Accepts one of the following values:
8269 Simple filter coefficient set.
8271 More-complex filter coefficient set.
8273 Default value is @samp{complex}.
8276 Specify which frames to deinterlace. Accept one of the following values:
8280 Deinterlace all frames,
8282 Only deinterlace frames marked as interlaced.
8285 Default value is @samp{all}.
8291 Deinterlace the input video ("yadif" means "yet another deinterlacing
8294 This filter accepts the following options:
8300 The interlacing mode to adopt, accepts one of the following values:
8304 output 1 frame for each frame
8306 output 1 frame for each field
8307 @item 2, send_frame_nospatial
8308 like @code{send_frame} but skip spatial interlacing check
8309 @item 3, send_field_nospatial
8310 like @code{send_field} but skip spatial interlacing check
8313 Default value is @code{send_frame}.
8316 The picture field parity assumed for the input interlaced video, accepts one of
8317 the following values:
8321 assume top field first
8323 assume bottom field first
8325 enable automatic detection
8328 Default value is @code{auto}.
8329 If interlacing is unknown or decoder does not export this information,
8330 top field first will be assumed.
8333 Specify which frames to deinterlace. Accept one of the following
8338 deinterlace all frames
8340 only deinterlace frames marked as interlaced
8343 Default value is @code{all}.
8346 @c man end VIDEO FILTERS
8348 @chapter Video Sources
8349 @c man begin VIDEO SOURCES
8351 Below is a description of the currently available video sources.
8355 Buffer video frames, and make them available to the filter chain.
8357 This source is mainly intended for a programmatic use, in particular
8358 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
8360 This source accepts the following options:
8365 Specify the size (width and height) of the buffered video frames. For the
8366 syntax of this option, check the "Video size" section in the ffmpeg-utils
8376 A string representing the pixel format of the buffered video frames.
8377 It may be a number corresponding to a pixel format, or a pixel format
8381 Specify the timebase assumed by the timestamps of the buffered frames.
8384 Specify the frame rate expected for the video stream.
8386 @item pixel_aspect, sar
8387 Specify the sample aspect ratio assumed by the video frames.
8390 Specify the optional parameters to be used for the scale filter which
8391 is automatically inserted when an input change is detected in the
8392 input size or format.
8397 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
8400 will instruct the source to accept video frames with size 320x240 and
8401 with format "yuv410p", assuming 1/24 as the timestamps timebase and
8402 square pixels (1:1 sample aspect ratio).
8403 Since the pixel format with name "yuv410p" corresponds to the number 6
8404 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
8405 this example corresponds to:
8407 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
8410 Alternatively, the options can be specified as a flat string, but this
8411 syntax is deprecated:
8413 @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}]
8417 Create a pattern generated by an elementary cellular automaton.
8419 The initial state of the cellular automaton can be defined through the
8420 @option{filename}, and @option{pattern} options. If such options are
8421 not specified an initial state is created randomly.
8423 At each new frame a new row in the video is filled with the result of
8424 the cellular automaton next generation. The behavior when the whole
8425 frame is filled is defined by the @option{scroll} option.
8427 This source accepts the following options:
8431 Read the initial cellular automaton state, i.e. the starting row, from
8433 In the file, each non-whitespace character is considered an alive
8434 cell, a newline will terminate the row, and further characters in the
8435 file will be ignored.
8438 Read the initial cellular automaton state, i.e. the starting row, from
8439 the specified string.
8441 Each non-whitespace character in the string is considered an alive
8442 cell, a newline will terminate the row, and further characters in the
8443 string will be ignored.
8446 Set the video rate, that is the number of frames generated per second.
8449 @item random_fill_ratio, ratio
8450 Set the random fill ratio for the initial cellular automaton row. It
8451 is a floating point number value ranging from 0 to 1, defaults to
8454 This option is ignored when a file or a pattern is specified.
8456 @item random_seed, seed
8457 Set the seed for filling randomly the initial row, must be an integer
8458 included between 0 and UINT32_MAX. If not specified, or if explicitly
8459 set to -1, the filter will try to use a good random seed on a best
8463 Set the cellular automaton rule, it is a number ranging from 0 to 255.
8464 Default value is 110.
8467 Set the size of the output video. For the syntax of this option, check
8468 the "Video size" section in the ffmpeg-utils manual.
8470 If @option{filename} or @option{pattern} is specified, the size is set
8471 by default to the width of the specified initial state row, and the
8472 height is set to @var{width} * PHI.
8474 If @option{size} is set, it must contain the width of the specified
8475 pattern string, and the specified pattern will be centered in the
8478 If a filename or a pattern string is not specified, the size value
8479 defaults to "320x518" (used for a randomly generated initial state).
8482 If set to 1, scroll the output upward when all the rows in the output
8483 have been already filled. If set to 0, the new generated row will be
8484 written over the top row just after the bottom row is filled.
8487 @item start_full, full
8488 If set to 1, completely fill the output with generated rows before
8489 outputting the first frame.
8490 This is the default behavior, for disabling set the value to 0.
8493 If set to 1, stitch the left and right row edges together.
8494 This is the default behavior, for disabling set the value to 0.
8497 @subsection Examples
8501 Read the initial state from @file{pattern}, and specify an output of
8504 cellauto=f=pattern:s=200x400
8508 Generate a random initial row with a width of 200 cells, with a fill
8511 cellauto=ratio=2/3:s=200x200
8515 Create a pattern generated by rule 18 starting by a single alive cell
8516 centered on an initial row with width 100:
8518 cellauto=p=@@:s=100x400:full=0:rule=18
8522 Specify a more elaborated initial pattern:
8524 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
8531 Generate a Mandelbrot set fractal, and progressively zoom towards the
8532 point specified with @var{start_x} and @var{start_y}.
8534 This source accepts the following options:
8539 Set the terminal pts value. Default value is 400.
8542 Set the terminal scale value.
8543 Must be a floating point value. Default value is 0.3.
8546 Set the inner coloring mode, that is the algorithm used to draw the
8547 Mandelbrot fractal internal region.
8549 It shall assume one of the following values:
8554 Show time until convergence.
8556 Set color based on point closest to the origin of the iterations.
8561 Default value is @var{mincol}.
8564 Set the bailout value. Default value is 10.0.
8567 Set the maximum of iterations performed by the rendering
8568 algorithm. Default value is 7189.
8571 Set outer coloring mode.
8572 It shall assume one of following values:
8574 @item iteration_count
8575 Set iteration cound mode.
8576 @item normalized_iteration_count
8577 set normalized iteration count mode.
8579 Default value is @var{normalized_iteration_count}.
8582 Set frame rate, expressed as number of frames per second. Default
8586 Set frame size. For the syntax of this option, check the "Video
8587 size" section in the ffmpeg-utils manual. Default value is "640x480".
8590 Set the initial scale value. Default value is 3.0.
8593 Set the initial x position. Must be a floating point value between
8594 -100 and 100. Default value is -0.743643887037158704752191506114774.
8597 Set the initial y position. Must be a floating point value between
8598 -100 and 100. Default value is -0.131825904205311970493132056385139.
8603 Generate various test patterns, as generated by the MPlayer test filter.
8605 The size of the generated video is fixed, and is 256x256.
8606 This source is useful in particular for testing encoding features.
8608 This source accepts the following options:
8613 Specify the frame rate of the sourced video, as the number of frames
8614 generated per second. It has to be a string in the format
8615 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
8616 number or a valid video frame rate abbreviation. The default value is
8620 Set the video duration of the sourced video. The accepted syntax is:
8625 See also the function @code{av_parse_time()}.
8627 If not specified, or the expressed duration is negative, the video is
8628 supposed to be generated forever.
8632 Set the number or the name of the test to perform. Supported tests are:
8647 Default value is "all", which will cycle through the list of all tests.
8650 For example the following:
8655 will generate a "dc_luma" test pattern.
8659 Provide a frei0r source.
8661 To enable compilation of this filter you need to install the frei0r
8662 header and configure FFmpeg with @code{--enable-frei0r}.
8664 This source accepts the following options:
8669 The size of the video to generate. For the syntax of this option, check the
8670 "Video size" section in the ffmpeg-utils manual.
8673 Framerate of the generated video, may be a string of the form
8674 @var{num}/@var{den} or a frame rate abbreviation.
8677 The name to the frei0r source to load. For more information regarding frei0r and
8678 how to set the parameters read the section @ref{frei0r} in the description of
8682 A '|'-separated list of parameters to pass to the frei0r source.
8686 For example, to generate a frei0r partik0l source with size 200x200
8687 and frame rate 10 which is overlayed on the overlay filter main input:
8689 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
8694 Generate a life pattern.
8696 This source is based on a generalization of John Conway's life game.
8698 The sourced input represents a life grid, each pixel represents a cell
8699 which can be in one of two possible states, alive or dead. Every cell
8700 interacts with its eight neighbours, which are the cells that are
8701 horizontally, vertically, or diagonally adjacent.
8703 At each interaction the grid evolves according to the adopted rule,
8704 which specifies the number of neighbor alive cells which will make a
8705 cell stay alive or born. The @option{rule} option allows to specify
8708 This source accepts the following options:
8712 Set the file from which to read the initial grid state. In the file,
8713 each non-whitespace character is considered an alive cell, and newline
8714 is used to delimit the end of each row.
8716 If this option is not specified, the initial grid is generated
8720 Set the video rate, that is the number of frames generated per second.
8723 @item random_fill_ratio, ratio
8724 Set the random fill ratio for the initial random grid. It is a
8725 floating point number value ranging from 0 to 1, defaults to 1/PHI.
8726 It is ignored when a file is specified.
8728 @item random_seed, seed
8729 Set the seed for filling the initial random grid, must be an integer
8730 included between 0 and UINT32_MAX. If not specified, or if explicitly
8731 set to -1, the filter will try to use a good random seed on a best
8737 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
8738 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
8739 @var{NS} specifies the number of alive neighbor cells which make a
8740 live cell stay alive, and @var{NB} the number of alive neighbor cells
8741 which make a dead cell to become alive (i.e. to "born").
8742 "s" and "b" can be used in place of "S" and "B", respectively.
8744 Alternatively a rule can be specified by an 18-bits integer. The 9
8745 high order bits are used to encode the next cell state if it is alive
8746 for each number of neighbor alive cells, the low order bits specify
8747 the rule for "borning" new cells. Higher order bits encode for an
8748 higher number of neighbor cells.
8749 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
8750 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
8752 Default value is "S23/B3", which is the original Conway's game of life
8753 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
8754 cells, and will born a new cell if there are three alive cells around
8758 Set the size of the output video. For the syntax of this option, check the
8759 "Video size" section in the ffmpeg-utils manual.
8761 If @option{filename} is specified, the size is set by default to the
8762 same size of the input file. If @option{size} is set, it must contain
8763 the size specified in the input file, and the initial grid defined in
8764 that file is centered in the larger resulting area.
8766 If a filename is not specified, the size value defaults to "320x240"
8767 (used for a randomly generated initial grid).
8770 If set to 1, stitch the left and right grid edges together, and the
8771 top and bottom edges also. Defaults to 1.
8774 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
8775 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
8776 value from 0 to 255.
8779 Set the color of living (or new born) cells.
8782 Set the color of dead cells. If @option{mold} is set, this is the first color
8783 used to represent a dead cell.
8786 Set mold color, for definitely dead and moldy cells.
8788 For the syntax of these 3 color options, check the "Color" section in the
8789 ffmpeg-utils manual.
8792 @subsection Examples
8796 Read a grid from @file{pattern}, and center it on a grid of size
8799 life=f=pattern:s=300x300
8803 Generate a random grid of size 200x200, with a fill ratio of 2/3:
8805 life=ratio=2/3:s=200x200
8809 Specify a custom rule for evolving a randomly generated grid:
8815 Full example with slow death effect (mold) using @command{ffplay}:
8817 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
8822 @anchor{haldclutsrc}
8826 @anchor{smptehdbars}
8828 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
8830 The @code{color} source provides an uniformly colored input.
8832 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
8833 @ref{haldclut} filter.
8835 The @code{nullsrc} source returns unprocessed video frames. It is
8836 mainly useful to be employed in analysis / debugging tools, or as the
8837 source for filters which ignore the input data.
8839 The @code{rgbtestsrc} source generates an RGB test pattern useful for
8840 detecting RGB vs BGR issues. You should see a red, green and blue
8841 stripe from top to bottom.
8843 The @code{smptebars} source generates a color bars pattern, based on
8844 the SMPTE Engineering Guideline EG 1-1990.
8846 The @code{smptehdbars} source generates a color bars pattern, based on
8847 the SMPTE RP 219-2002.
8849 The @code{testsrc} source generates a test video pattern, showing a
8850 color pattern, a scrolling gradient and a timestamp. This is mainly
8851 intended for testing purposes.
8853 The sources accept the following options:
8858 Specify the color of the source, only available in the @code{color}
8859 source. For the syntax of this option, check the "Color" section in the
8860 ffmpeg-utils manual.
8863 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
8864 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
8865 pixels to be used as identity matrix for 3D lookup tables. Each component is
8866 coded on a @code{1/(N*N)} scale.
8869 Specify the size of the sourced video. For the syntax of this option, check the
8870 "Video size" section in the ffmpeg-utils manual. The default value is
8873 This option is not available with the @code{haldclutsrc} filter.
8876 Specify the frame rate of the sourced video, as the number of frames
8877 generated per second. It has to be a string in the format
8878 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
8879 number or a valid video frame rate abbreviation. The default value is
8883 Set the sample aspect ratio of the sourced video.
8886 Set the video duration of the sourced video. The accepted syntax is:
8888 [-]HH[:MM[:SS[.m...]]]
8891 See also the function @code{av_parse_time()}.
8893 If not specified, or the expressed duration is negative, the video is
8894 supposed to be generated forever.
8897 Set the number of decimals to show in the timestamp, only available in the
8898 @code{testsrc} source.
8900 The displayed timestamp value will correspond to the original
8901 timestamp value multiplied by the power of 10 of the specified
8902 value. Default value is 0.
8905 For example the following:
8907 testsrc=duration=5.3:size=qcif:rate=10
8910 will generate a video with a duration of 5.3 seconds, with size
8911 176x144 and a frame rate of 10 frames per second.
8913 The following graph description will generate a red source
8914 with an opacity of 0.2, with size "qcif" and a frame rate of 10
8917 color=c=red@@0.2:s=qcif:r=10
8920 If the input content is to be ignored, @code{nullsrc} can be used. The
8921 following command generates noise in the luminance plane by employing
8922 the @code{geq} filter:
8924 nullsrc=s=256x256, geq=random(1)*255:128:128
8927 @subsection Commands
8929 The @code{color} source supports the following commands:
8933 Set the color of the created image. Accepts the same syntax of the
8934 corresponding @option{color} option.
8937 @c man end VIDEO SOURCES
8939 @chapter Video Sinks
8940 @c man begin VIDEO SINKS
8942 Below is a description of the currently available video sinks.
8946 Buffer video frames, and make them available to the end of the filter
8949 This sink is mainly intended for a programmatic use, in particular
8950 through the interface defined in @file{libavfilter/buffersink.h}
8951 or the options system.
8953 It accepts a pointer to an AVBufferSinkContext structure, which
8954 defines the incoming buffers' formats, to be passed as the opaque
8955 parameter to @code{avfilter_init_filter} for initialization.
8959 Null video sink, do absolutely nothing with the input video. It is
8960 mainly useful as a template and to be employed in analysis / debugging
8963 @c man end VIDEO SINKS
8965 @chapter Multimedia Filters
8966 @c man begin MULTIMEDIA FILTERS
8968 Below is a description of the currently available multimedia filters.
8970 @section avectorscope
8972 Convert input audio to a video output, representing the audio vector
8975 The filter is used to measure the difference between channels of stereo
8976 audio stream. A monoaural signal, consisting of identical left and right
8977 signal, results in straight vertical line. Any stereo separation is visible
8978 as a deviation from this line, creating a Lissajous figure.
8979 If the straight (or deviation from it) but horizontal line appears this
8980 indicates that the left and right channels are out of phase.
8982 The filter accepts the following options:
8986 Set the vectorscope mode.
8988 Available values are:
8991 Lissajous rotated by 45 degrees.
8994 Same as above but not rotated.
8997 Default value is @samp{lissajous}.
9000 Set the video size for the output. For the syntax of this option, check the "Video size"
9001 section in the ffmpeg-utils manual. Default value is @code{400x400}.
9004 Set the output frame rate. Default value is @code{25}.
9009 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
9010 Allowed range is @code{[0, 255]}.
9015 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
9016 Allowed range is @code{[0, 255]}.
9019 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
9022 @subsection Examples
9026 Complete example using @command{ffplay}:
9028 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9029 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
9035 Concatenate audio and video streams, joining them together one after the
9038 The filter works on segments of synchronized video and audio streams. All
9039 segments must have the same number of streams of each type, and that will
9040 also be the number of streams at output.
9042 The filter accepts the following options:
9047 Set the number of segments. Default is 2.
9050 Set the number of output video streams, that is also the number of video
9051 streams in each segment. Default is 1.
9054 Set the number of output audio streams, that is also the number of video
9055 streams in each segment. Default is 0.
9058 Activate unsafe mode: do not fail if segments have a different format.
9062 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
9063 @var{a} audio outputs.
9065 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
9066 segment, in the same order as the outputs, then the inputs for the second
9069 Related streams do not always have exactly the same duration, for various
9070 reasons including codec frame size or sloppy authoring. For that reason,
9071 related synchronized streams (e.g. a video and its audio track) should be
9072 concatenated at once. The concat filter will use the duration of the longest
9073 stream in each segment (except the last one), and if necessary pad shorter
9074 audio streams with silence.
9076 For this filter to work correctly, all segments must start at timestamp 0.
9078 All corresponding streams must have the same parameters in all segments; the
9079 filtering system will automatically select a common pixel format for video
9080 streams, and a common sample format, sample rate and channel layout for
9081 audio streams, but other settings, such as resolution, must be converted
9082 explicitly by the user.
9084 Different frame rates are acceptable but will result in variable frame rate
9085 at output; be sure to configure the output file to handle it.
9087 @subsection Examples
9091 Concatenate an opening, an episode and an ending, all in bilingual version
9092 (video in stream 0, audio in streams 1 and 2):
9094 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
9095 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
9096 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
9097 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
9101 Concatenate two parts, handling audio and video separately, using the
9102 (a)movie sources, and adjusting the resolution:
9104 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
9105 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
9106 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
9108 Note that a desync will happen at the stitch if the audio and video streams
9109 do not have exactly the same duration in the first file.
9115 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
9116 it unchanged. By default, it logs a message at a frequency of 10Hz with the
9117 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
9118 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
9120 The filter also has a video output (see the @var{video} option) with a real
9121 time graph to observe the loudness evolution. The graphic contains the logged
9122 message mentioned above, so it is not printed anymore when this option is set,
9123 unless the verbose logging is set. The main graphing area contains the
9124 short-term loudness (3 seconds of analysis), and the gauge on the right is for
9125 the momentary loudness (400 milliseconds).
9127 More information about the Loudness Recommendation EBU R128 on
9128 @url{http://tech.ebu.ch/loudness}.
9130 The filter accepts the following options:
9135 Activate the video output. The audio stream is passed unchanged whether this
9136 option is set or no. The video stream will be the first output stream if
9137 activated. Default is @code{0}.
9140 Set the video size. This option is for video only. For the syntax of this
9141 option, check the "Video size" section in the ffmpeg-utils manual. Default
9142 and minimum resolution is @code{640x480}.
9145 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
9146 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
9147 other integer value between this range is allowed.
9150 Set metadata injection. If set to @code{1}, the audio input will be segmented
9151 into 100ms output frames, each of them containing various loudness information
9152 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
9154 Default is @code{0}.
9157 Force the frame logging level.
9159 Available values are:
9162 information logging level
9164 verbose logging level
9167 By default, the logging level is set to @var{info}. If the @option{video} or
9168 the @option{metadata} options are set, it switches to @var{verbose}.
9171 @subsection Examples
9175 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
9177 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
9181 Run an analysis with @command{ffmpeg}:
9183 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
9187 @section interleave, ainterleave
9189 Temporally interleave frames from several inputs.
9191 @code{interleave} works with video inputs, @code{ainterleave} with audio.
9193 These filters read frames from several inputs and send the oldest
9194 queued frame to the output.
9196 Input streams must have a well defined, monotonically increasing frame
9199 In order to submit one frame to output, these filters need to enqueue
9200 at least one frame for each input, so they cannot work in case one
9201 input is not yet terminated and will not receive incoming frames.
9203 For example consider the case when one input is a @code{select} filter
9204 which always drop input frames. The @code{interleave} filter will keep
9205 reading from that input, but it will never be able to send new frames
9206 to output until the input will send an end-of-stream signal.
9208 Also, depending on inputs synchronization, the filters will drop
9209 frames in case one input receives more frames than the other ones, and
9210 the queue is already filled.
9212 These filters accept the following options:
9216 Set the number of different inputs, it is 2 by default.
9219 @subsection Examples
9223 Interleave frames belonging to different streams using @command{ffmpeg}:
9225 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
9229 Add flickering blur effect:
9231 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
9235 @section perms, aperms
9237 Set read/write permissions for the output frames.
9239 These filters are mainly aimed at developers to test direct path in the
9240 following filter in the filtergraph.
9242 The filters accept the following options:
9246 Select the permissions mode.
9248 It accepts the following values:
9251 Do nothing. This is the default.
9253 Set all the output frames read-only.
9255 Set all the output frames directly writable.
9257 Make the frame read-only if writable, and writable if read-only.
9259 Set each output frame read-only or writable randomly.
9263 Set the seed for the @var{random} mode, must be an integer included between
9264 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
9265 @code{-1}, the filter will try to use a good random seed on a best effort
9269 Note: in case of auto-inserted filter between the permission filter and the
9270 following one, the permission might not be received as expected in that
9271 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
9272 perms/aperms filter can avoid this problem.
9274 @section select, aselect
9276 Select frames to pass in output.
9278 This filter accepts the following options:
9283 Set expression, which is evaluated for each input frame.
9285 If the expression is evaluated to zero, the frame is discarded.
9287 If the evaluation result is negative or NaN, the frame is sent to the
9288 first output; otherwise it is sent to the output with index
9289 @code{ceil(val)-1}, assuming that the input index starts from 0.
9291 For example a value of @code{1.2} corresponds to the output with index
9292 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
9295 Set the number of outputs. The output to which to send the selected
9296 frame is based on the result of the evaluation. Default value is 1.
9299 The expression can contain the following constants:
9303 the sequential number of the filtered frame, starting from 0
9306 the sequential number of the selected frame, starting from 0
9308 @item prev_selected_n
9309 the sequential number of the last selected frame, NAN if undefined
9312 timebase of the input timestamps
9315 the PTS (Presentation TimeStamp) of the filtered video frame,
9316 expressed in @var{TB} units, NAN if undefined
9319 the PTS (Presentation TimeStamp) of the filtered video frame,
9320 expressed in seconds, NAN if undefined
9323 the PTS of the previously filtered video frame, NAN if undefined
9325 @item prev_selected_pts
9326 the PTS of the last previously filtered video frame, NAN if undefined
9328 @item prev_selected_t
9329 the PTS of the last previously selected video frame, NAN if undefined
9332 the PTS of the first video frame in the video, NAN if undefined
9335 the time of the first video frame in the video, NAN if undefined
9337 @item pict_type @emph{(video only)}
9338 the type of the filtered frame, can assume one of the following
9350 @item interlace_type @emph{(video only)}
9351 the frame interlace type, can assume one of the following values:
9354 the frame is progressive (not interlaced)
9356 the frame is top-field-first
9358 the frame is bottom-field-first
9361 @item consumed_sample_n @emph{(audio only)}
9362 the number of selected samples before the current frame
9364 @item samples_n @emph{(audio only)}
9365 the number of samples in the current frame
9367 @item sample_rate @emph{(audio only)}
9368 the input sample rate
9371 1 if the filtered frame is a key-frame, 0 otherwise
9374 the position in the file of the filtered frame, -1 if the information
9375 is not available (e.g. for synthetic video)
9377 @item scene @emph{(video only)}
9378 value between 0 and 1 to indicate a new scene; a low value reflects a low
9379 probability for the current frame to introduce a new scene, while a higher
9380 value means the current frame is more likely to be one (see the example below)
9384 The default value of the select expression is "1".
9386 @subsection Examples
9390 Select all frames in input:
9395 The example above is the same as:
9407 Select only I-frames:
9409 select='eq(pict_type\,I)'
9413 Select one frame every 100:
9415 select='not(mod(n\,100))'
9419 Select only frames contained in the 10-20 time interval:
9421 select=between(t\,10\,20)
9425 Select only I frames contained in the 10-20 time interval:
9427 select=between(t\,10\,20)*eq(pict_type\,I)
9431 Select frames with a minimum distance of 10 seconds:
9433 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
9437 Use aselect to select only audio frames with samples number > 100:
9439 aselect='gt(samples_n\,100)'
9443 Create a mosaic of the first scenes:
9445 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
9448 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
9452 Send even and odd frames to separate outputs, and compose them:
9454 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
9458 @section sendcmd, asendcmd
9460 Send commands to filters in the filtergraph.
9462 These filters read commands to be sent to other filters in the
9465 @code{sendcmd} must be inserted between two video filters,
9466 @code{asendcmd} must be inserted between two audio filters, but apart
9467 from that they act the same way.
9469 The specification of commands can be provided in the filter arguments
9470 with the @var{commands} option, or in a file specified by the
9471 @var{filename} option.
9473 These filters accept the following options:
9476 Set the commands to be read and sent to the other filters.
9478 Set the filename of the commands to be read and sent to the other
9482 @subsection Commands syntax
9484 A commands description consists of a sequence of interval
9485 specifications, comprising a list of commands to be executed when a
9486 particular event related to that interval occurs. The occurring event
9487 is typically the current frame time entering or leaving a given time
9490 An interval is specified by the following syntax:
9492 @var{START}[-@var{END}] @var{COMMANDS};
9495 The time interval is specified by the @var{START} and @var{END} times.
9496 @var{END} is optional and defaults to the maximum time.
9498 The current frame time is considered within the specified interval if
9499 it is included in the interval [@var{START}, @var{END}), that is when
9500 the time is greater or equal to @var{START} and is lesser than
9503 @var{COMMANDS} consists of a sequence of one or more command
9504 specifications, separated by ",", relating to that interval. The
9505 syntax of a command specification is given by:
9507 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
9510 @var{FLAGS} is optional and specifies the type of events relating to
9511 the time interval which enable sending the specified command, and must
9512 be a non-null sequence of identifier flags separated by "+" or "|" and
9513 enclosed between "[" and "]".
9515 The following flags are recognized:
9518 The command is sent when the current frame timestamp enters the
9519 specified interval. In other words, the command is sent when the
9520 previous frame timestamp was not in the given interval, and the
9524 The command is sent when the current frame timestamp leaves the
9525 specified interval. In other words, the command is sent when the
9526 previous frame timestamp was in the given interval, and the
9530 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
9533 @var{TARGET} specifies the target of the command, usually the name of
9534 the filter class or a specific filter instance name.
9536 @var{COMMAND} specifies the name of the command for the target filter.
9538 @var{ARG} is optional and specifies the optional list of argument for
9539 the given @var{COMMAND}.
9541 Between one interval specification and another, whitespaces, or
9542 sequences of characters starting with @code{#} until the end of line,
9543 are ignored and can be used to annotate comments.
9545 A simplified BNF description of the commands specification syntax
9548 @var{COMMAND_FLAG} ::= "enter" | "leave"
9549 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
9550 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
9551 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
9552 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
9553 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
9556 @subsection Examples
9560 Specify audio tempo change at second 4:
9562 asendcmd=c='4.0 atempo tempo 1.5',atempo
9566 Specify a list of drawtext and hue commands in a file.
9568 # show text in the interval 5-10
9569 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
9570 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
9572 # desaturate the image in the interval 15-20
9573 15.0-20.0 [enter] hue s 0,
9574 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
9576 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
9578 # apply an exponential saturation fade-out effect, starting from time 25
9579 25 [enter] hue s exp(25-t)
9582 A filtergraph allowing to read and process the above command list
9583 stored in a file @file{test.cmd}, can be specified with:
9585 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
9590 @section setpts, asetpts
9592 Change the PTS (presentation timestamp) of the input frames.
9594 @code{setpts} works on video frames, @code{asetpts} on audio frames.
9596 This filter accepts the following options:
9601 The expression which is evaluated for each frame to construct its timestamp.
9605 The expression is evaluated through the eval API and can contain the following
9610 frame rate, only defined for constant frame-rate video
9613 the presentation timestamp in input
9616 the count of the input frame for video or the number of consumed samples,
9617 not including the current frame for audio, starting from 0.
9619 @item NB_CONSUMED_SAMPLES
9620 the number of consumed samples, not including the current frame (only
9624 the number of samples in the current frame (only audio)
9626 @item SAMPLE_RATE, SR
9630 the PTS of the first frame
9633 the time in seconds of the first frame
9636 tell if the current frame is interlaced
9639 the time in seconds of the current frame
9642 original position in the file of the frame, or undefined if undefined
9643 for the current frame
9649 previous input time in seconds
9655 previous output time in seconds
9658 wallclock (RTC) time in microseconds. This is deprecated, use time(0)
9662 wallclock (RTC) time at the start of the movie in microseconds
9665 timebase of the input timestamps
9669 @subsection Examples
9673 Start counting PTS from zero
9679 Apply fast motion effect:
9685 Apply slow motion effect:
9691 Set fixed rate of 25 frames per second:
9697 Set fixed rate 25 fps with some jitter:
9699 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
9703 Apply an offset of 10 seconds to the input PTS:
9709 Generate timestamps from a "live source" and rebase onto the current timebase:
9711 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
9715 Generate timestamps by counting samples:
9722 @section settb, asettb
9724 Set the timebase to use for the output frames timestamps.
9725 It is mainly useful for testing timebase configuration.
9727 This filter accepts the following options:
9732 The expression which is evaluated into the output timebase.
9736 The value for @option{tb} is an arithmetic expression representing a
9737 rational. The expression can contain the constants "AVTB" (the default
9738 timebase), "intb" (the input timebase) and "sr" (the sample rate,
9739 audio only). Default value is "intb".
9741 @subsection Examples
9745 Set the timebase to 1/25:
9751 Set the timebase to 1/10:
9757 Set the timebase to 1001/1000:
9763 Set the timebase to 2*intb:
9769 Set the default timebase value:
9775 @section showspectrum
9777 Convert input audio to a video output, representing the audio frequency
9780 The filter accepts the following options:
9784 Specify the video size for the output. For the syntax of this option, check
9785 the "Video size" section in the ffmpeg-utils manual. Default value is
9789 Specify if the spectrum should slide along the window. Default value is
9793 Specify display mode.
9795 It accepts the following values:
9798 all channels are displayed in the same row
9800 all channels are displayed in separate rows
9803 Default value is @samp{combined}.
9806 Specify display color mode.
9808 It accepts the following values:
9811 each channel is displayed in a separate color
9813 each channel is is displayed using the same color scheme
9816 Default value is @samp{channel}.
9819 Specify scale used for calculating intensity color values.
9821 It accepts the following values:
9826 square root, default
9833 Default value is @samp{sqrt}.
9836 Set saturation modifier for displayed colors. Negative values provide
9837 alternative color scheme. @code{0} is no saturation at all.
9838 Saturation must be in [-10.0, 10.0] range.
9839 Default value is @code{1}.
9842 Set window function.
9844 It accepts the following values:
9847 No samples pre-processing (do not expect this to be faster)
9856 Default value is @code{hann}.
9859 The usage is very similar to the showwaves filter; see the examples in that
9862 @subsection Examples
9866 Large window with logarithmic color scaling:
9868 showspectrum=s=1280x480:scale=log
9872 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
9874 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9875 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
9881 Convert input audio to a video output, representing the samples waves.
9883 The filter accepts the following options:
9887 Specify the video size for the output. For the syntax of this option, check
9888 the "Video size" section in the ffmpeg-utils manual. Default value
9894 Available values are:
9897 Draw a point for each sample.
9900 Draw a vertical line for each sample.
9903 Default value is @code{point}.
9906 Set the number of samples which are printed on the same column. A
9907 larger value will decrease the frame rate. Must be a positive
9908 integer. This option can be set only if the value for @var{rate}
9909 is not explicitly specified.
9912 Set the (approximate) output frame rate. This is done by setting the
9913 option @var{n}. Default value is "25".
9917 @subsection Examples
9921 Output the input file audio and the corresponding video representation
9924 amovie=a.mp3,asplit[out0],showwaves[out1]
9928 Create a synthetic signal and show it with showwaves, forcing a
9929 frame rate of 30 frames per second:
9931 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
9935 @section split, asplit
9937 Split input into several identical outputs.
9939 @code{asplit} works with audio input, @code{split} with video.
9941 The filter accepts a single parameter which specifies the number of outputs. If
9942 unspecified, it defaults to 2.
9944 @subsection Examples
9948 Create two separate outputs from the same input:
9950 [in] split [out0][out1]
9954 To create 3 or more outputs, you need to specify the number of
9957 [in] asplit=3 [out0][out1][out2]
9961 Create two separate outputs from the same input, one cropped and
9964 [in] split [splitout1][splitout2];
9965 [splitout1] crop=100:100:0:0 [cropout];
9966 [splitout2] pad=200:200:100:100 [padout];
9970 Create 5 copies of the input audio with @command{ffmpeg}:
9972 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
9978 Receive commands sent through a libzmq client, and forward them to
9979 filters in the filtergraph.
9981 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
9982 must be inserted between two video filters, @code{azmq} between two
9985 To enable these filters you need to install the libzmq library and
9986 headers and configure FFmpeg with @code{--enable-libzmq}.
9988 For more information about libzmq see:
9989 @url{http://www.zeromq.org/}
9991 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
9992 receives messages sent through a network interface defined by the
9993 @option{bind_address} option.
9995 The received message must be in the form:
9997 @var{TARGET} @var{COMMAND} [@var{ARG}]
10000 @var{TARGET} specifies the target of the command, usually the name of
10001 the filter class or a specific filter instance name.
10003 @var{COMMAND} specifies the name of the command for the target filter.
10005 @var{ARG} is optional and specifies the optional argument list for the
10006 given @var{COMMAND}.
10008 Upon reception, the message is processed and the corresponding command
10009 is injected into the filtergraph. Depending on the result, the filter
10010 will send a reply to the client, adopting the format:
10012 @var{ERROR_CODE} @var{ERROR_REASON}
10016 @var{MESSAGE} is optional.
10018 @subsection Examples
10020 Look at @file{tools/zmqsend} for an example of a zmq client which can
10021 be used to send commands processed by these filters.
10023 Consider the following filtergraph generated by @command{ffplay}
10025 ffplay -dumpgraph 1 -f lavfi "
10026 color=s=100x100:c=red [l];
10027 color=s=100x100:c=blue [r];
10028 nullsrc=s=200x100, zmq [bg];
10029 [bg][l] overlay [bg+l];
10030 [bg+l][r] overlay=x=100 "
10033 To change the color of the left side of the video, the following
10034 command can be used:
10036 echo Parsed_color_0 c yellow | tools/zmqsend
10039 To change the right side:
10041 echo Parsed_color_1 c pink | tools/zmqsend
10044 @c man end MULTIMEDIA FILTERS
10046 @chapter Multimedia Sources
10047 @c man begin MULTIMEDIA SOURCES
10049 Below is a description of the currently available multimedia sources.
10053 This is the same as @ref{movie} source, except it selects an audio
10059 Read audio and/or video stream(s) from a movie container.
10061 This filter accepts the following options:
10065 The name of the resource to read (not necessarily a file but also a device or a
10066 stream accessed through some protocol).
10068 @item format_name, f
10069 Specifies the format assumed for the movie to read, and can be either
10070 the name of a container or an input device. If not specified the
10071 format is guessed from @var{movie_name} or by probing.
10073 @item seek_point, sp
10074 Specifies the seek point in seconds, the frames will be output
10075 starting from this seek point, the parameter is evaluated with
10076 @code{av_strtod} so the numerical value may be suffixed by an IS
10077 postfix. Default value is "0".
10080 Specifies the streams to read. Several streams can be specified,
10081 separated by "+". The source will then have as many outputs, in the
10082 same order. The syntax is explained in the ``Stream specifiers''
10083 section in the ffmpeg manual. Two special names, "dv" and "da" specify
10084 respectively the default (best suited) video and audio stream. Default
10085 is "dv", or "da" if the filter is called as "amovie".
10087 @item stream_index, si
10088 Specifies the index of the video stream to read. If the value is -1,
10089 the best suited video stream will be automatically selected. Default
10090 value is "-1". Deprecated. If the filter is called "amovie", it will select
10091 audio instead of video.
10094 Specifies how many times to read the stream in sequence.
10095 If the value is less than 1, the stream will be read again and again.
10096 Default value is "1".
10098 Note that when the movie is looped the source timestamps are not
10099 changed, so it will generate non monotonically increasing timestamps.
10102 This filter allows to overlay a second video on top of main input of
10103 a filtergraph as shown in this graph:
10105 input -----------> deltapts0 --> overlay --> output
10108 movie --> scale--> deltapts1 -------+
10111 @subsection Examples
10115 Skip 3.2 seconds from the start of the avi file in.avi, and overlay it
10116 on top of the input labelled as "in":
10118 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
10119 [in] setpts=PTS-STARTPTS [main];
10120 [main][over] overlay=16:16 [out]
10124 Read from a video4linux2 device, and overlay it on top of the input
10127 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
10128 [in] setpts=PTS-STARTPTS [main];
10129 [main][over] overlay=16:16 [out]
10133 Read the first video stream and the audio stream with id 0x81 from
10134 dvd.vob; the video is connected to the pad named "video" and the audio is
10135 connected to the pad named "audio":
10137 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
10141 @c man end MULTIMEDIA SOURCES