1 @chapter Filtering Introduction
2 @c man begin FILTERING INTRODUCTION
4 Filtering in FFmpeg is enabled through the libavfilter library.
6 In libavfilter, a filter can have multiple inputs and multiple
8 To illustrate the sorts of things that are possible, we consider the
13 input --> split ---------------------> overlay --> output
16 +-----> crop --> vflip -------+
19 This filtergraph splits the input stream in two streams, then sends one
20 stream through the crop filter and the vflip filter, before merging it
21 back with the other stream by overlaying it on top. You can use the
22 following command to achieve this:
25 ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
28 The result will be that the top half of the video is mirrored
29 onto the bottom half of the output video.
31 Filters in the same linear chain are separated by commas, and distinct
32 linear chains of filters are separated by semicolons. In our example,
33 @var{crop,vflip} are in one linear chain, @var{split} and
34 @var{overlay} are separately in another. The points where the linear
35 chains join are labelled by names enclosed in square brackets. In the
36 example, the split filter generates two outputs that are associated to
37 the labels @var{[main]} and @var{[tmp]}.
39 The stream sent to the second output of @var{split}, labelled as
40 @var{[tmp]}, is processed through the @var{crop} filter, which crops
41 away the lower half part of the video, and then vertically flipped. The
42 @var{overlay} filter takes in input the first unchanged output of the
43 split filter (which was labelled as @var{[main]}), and overlay on its
44 lower half the output generated by the @var{crop,vflip} filterchain.
46 Some filters take in input a list of parameters: they are specified
47 after the filter name and an equal sign, and are separated from each other
50 There exist so-called @var{source filters} that do not have an
51 audio/video input, and @var{sink filters} that will not have audio/video
54 @c man end FILTERING INTRODUCTION
57 @c man begin GRAPH2DOT
59 The @file{graph2dot} program included in the FFmpeg @file{tools}
60 directory can be used to parse a filtergraph description and issue a
61 corresponding textual representation in the dot language.
68 to see how to use @file{graph2dot}.
70 You can then pass the dot description to the @file{dot} program (from
71 the graphviz suite of programs) and obtain a graphical representation
74 For example the sequence of commands:
76 echo @var{GRAPH_DESCRIPTION} | \
77 tools/graph2dot -o graph.tmp && \
78 dot -Tpng graph.tmp -o graph.png && \
82 can be used to create and display an image representing the graph
83 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
84 a complete self-contained graph, with its inputs and outputs explicitly defined.
85 For example if your command line is of the form:
87 ffmpeg -i infile -vf scale=640:360 outfile
89 your @var{GRAPH_DESCRIPTION} string will need to be of the form:
91 nullsrc,scale=640:360,nullsink
93 you may also need to set the @var{nullsrc} parameters and add a @var{format}
94 filter in order to simulate a specific input file.
98 @chapter Filtergraph description
99 @c man begin FILTERGRAPH DESCRIPTION
101 A filtergraph is a directed graph of connected filters. It can contain
102 cycles, and there can be multiple links between a pair of
103 filters. Each link has one input pad on one side connecting it to one
104 filter from which it takes its input, and one output pad on the other
105 side connecting it to one filter accepting its output.
107 Each filter in a filtergraph is an instance of a filter class
108 registered in the application, which defines the features and the
109 number of input and output pads of the filter.
111 A filter with no input pads is called a "source", and a filter with no
112 output pads is called a "sink".
114 @anchor{Filtergraph syntax}
115 @section Filtergraph syntax
117 A filtergraph has a textual representation, which is
118 recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
119 options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the
120 @code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} functions defined in
121 @file{libavfilter/avfilter.h}.
123 A filterchain consists of a sequence of connected filters, each one
124 connected to the previous one in the sequence. A filterchain is
125 represented by a list of ","-separated filter descriptions.
127 A filtergraph consists of a sequence of filterchains. A sequence of
128 filterchains is represented by a list of ";"-separated filterchain
131 A filter is represented by a string of the form:
132 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
134 @var{filter_name} is the name of the filter class of which the
135 described filter is an instance of, and has to be the name of one of
136 the filter classes registered in the program.
137 The name of the filter class is optionally followed by a string
140 @var{arguments} is a string which contains the parameters used to
141 initialize the filter instance. It may have one of two forms:
145 A ':'-separated list of @var{key=value} pairs.
148 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
149 the option names in the order they are declared. E.g. the @code{fade} filter
150 declares three options in this order -- @option{type}, @option{start_frame} and
151 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
152 @var{in} is assigned to the option @option{type}, @var{0} to
153 @option{start_frame} and @var{30} to @option{nb_frames}.
156 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
157 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
158 follow the same constraints order of the previous point. The following
159 @var{key=value} pairs can be set in any preferred order.
163 If the option value itself is a list of items (e.g. the @code{format} filter
164 takes a list of pixel formats), the items in the list are usually separated by
167 The list of arguments can be quoted using the character "'" as initial
168 and ending mark, and the character '\' for escaping the characters
169 within the quoted text; otherwise the argument string is considered
170 terminated when the next special character (belonging to the set
171 "[]=;,") is encountered.
173 The name and arguments of the filter are optionally preceded and
174 followed by a list of link labels.
175 A link label allows one to name a link and associate it to a filter output
176 or input pad. The preceding labels @var{in_link_1}
177 ... @var{in_link_N}, are associated to the filter input pads,
178 the following labels @var{out_link_1} ... @var{out_link_M}, are
179 associated to the output pads.
181 When two link labels with the same name are found in the
182 filtergraph, a link between the corresponding input and output pad is
185 If an output pad is not labelled, it is linked by default to the first
186 unlabelled input pad of the next filter in the filterchain.
187 For example in the filterchain
189 nullsrc, split[L1], [L2]overlay, nullsink
191 the split filter instance has two output pads, and the overlay filter
192 instance two input pads. The first output pad of split is labelled
193 "L1", the first input pad of overlay is labelled "L2", and the second
194 output pad of split is linked to the second input pad of overlay,
195 which are both unlabelled.
197 In a complete filterchain all the unlabelled filter input and output
198 pads must be connected. A filtergraph is considered valid if all the
199 filter input and output pads of all the filterchains are connected.
201 Libavfilter will automatically insert @ref{scale} filters where format
202 conversion is required. It is possible to specify swscale flags
203 for those automatically inserted scalers by prepending
204 @code{sws_flags=@var{flags};}
205 to the filtergraph description.
207 Here is a BNF description of the filtergraph syntax:
209 @var{NAME} ::= sequence of alphanumeric characters and '_'
210 @var{LINKLABEL} ::= "[" @var{NAME} "]"
211 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
212 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
213 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
214 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
215 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
218 @section Notes on filtergraph escaping
220 Filtergraph description composition entails several levels of
221 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
222 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
223 information about the employed escaping procedure.
225 A first level escaping affects the content of each filter option
226 value, which may contain the special character @code{:} used to
227 separate values, or one of the escaping characters @code{\'}.
229 A second level escaping affects the whole filter description, which
230 may contain the escaping characters @code{\'} or the special
231 characters @code{[],;} used by the filtergraph description.
233 Finally, when you specify a filtergraph on a shell commandline, you
234 need to perform a third level escaping for the shell special
235 characters contained within it.
237 For example, consider the following string to be embedded in
238 the @ref{drawtext} filter description @option{text} value:
240 this is a 'string': may contain one, or more, special characters
243 This string contains the @code{'} special escaping character, and the
244 @code{:} special character, so it needs to be escaped in this way:
246 text=this is a \'string\'\: may contain one, or more, special characters
249 A second level of escaping is required when embedding the filter
250 description in a filtergraph description, in order to escape all the
251 filtergraph special characters. Thus the example above becomes:
253 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
255 (note that in addition to the @code{\'} escaping special characters,
256 also @code{,} needs to be escaped).
258 Finally an additional level of escaping is needed when writing the
259 filtergraph description in a shell command, which depends on the
260 escaping rules of the adopted shell. For example, assuming that
261 @code{\} is special and needs to be escaped with another @code{\}, the
262 previous string will finally result in:
264 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
267 @chapter Timeline editing
269 Some filters support a generic @option{enable} option. For the filters
270 supporting timeline editing, this option can be set to an expression which is
271 evaluated before sending a frame to the filter. If the evaluation is non-zero,
272 the filter will be enabled, otherwise the frame will be sent unchanged to the
273 next filter in the filtergraph.
275 The expression accepts the following values:
278 timestamp expressed in seconds, NAN if the input timestamp is unknown
281 sequential number of the input frame, starting from 0
284 the position in the file of the input frame, NAN if unknown
288 width and height of the input frame if video
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 Delay one or more audio channels.
320 Samples in delayed channel are filled with silence.
322 The filter accepts the following option:
326 Set list of delays in milliseconds for each channel separated by '|'.
327 At least one delay greater than 0 should be provided.
328 Unused delays will be silently ignored. If number of given delays is
329 smaller than number of channels all remaining channels will not be delayed.
336 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
337 the second channel (and any other channels that may be present) unchanged.
345 Apply echoing to the input audio.
347 Echoes are reflected sound and can occur naturally amongst mountains
348 (and sometimes large buildings) when talking or shouting; digital echo
349 effects emulate this behaviour and are often used to help fill out the
350 sound of a single instrument or vocal. The time difference between the
351 original signal and the reflection is the @code{delay}, and the
352 loudness of the reflected signal is the @code{decay}.
353 Multiple echoes can have different delays and decays.
355 A description of the accepted parameters follows.
359 Set input gain of reflected signal. Default is @code{0.6}.
362 Set output gain of reflected signal. Default is @code{0.3}.
365 Set list of time intervals in milliseconds between original signal and reflections
366 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
367 Default is @code{1000}.
370 Set list of loudnesses of reflected signals separated by '|'.
371 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
372 Default is @code{0.5}.
379 Make it sound as if there are twice as many instruments as are actually playing:
381 aecho=0.8:0.88:60:0.4
385 If delay is very short, then it sound like a (metallic) robot playing music:
391 A longer delay will sound like an open air concert in the mountains:
393 aecho=0.8:0.9:1000:0.3
397 Same as above but with one more mountain:
399 aecho=0.8:0.9:1000|1800:0.3|0.25
405 Modify an audio signal according to the specified expressions.
407 This filter accepts one or more expressions (one for each channel),
408 which are evaluated and used to modify a corresponding audio signal.
410 It accepts the following parameters:
414 Set the '|'-separated expressions list for each separate channel. If
415 the number of input channels is greater than the number of
416 expressions, the last specified expression is used for the remaining
419 @item channel_layout, c
420 Set output channel layout. If not specified, the channel layout is
421 specified by the number of expressions. If set to @samp{same}, it will
422 use by default the same input channel layout.
425 Each expression in @var{exprs} can contain the following constants and functions:
429 channel number of the current expression
432 number of the evaluated sample, starting from 0
438 time of the evaluated sample expressed in seconds
441 @item nb_out_channels
442 input and output number of channels
445 the value of input channel with number @var{CH}
448 Note: this filter is slow. For faster processing you should use a
457 aeval=val(ch)/2:c=same
461 Invert phase of the second channel:
469 Apply fade-in/out effect to input audio.
471 A description of the accepted parameters follows.
475 Specify the effect type, can be either @code{in} for fade-in, or
476 @code{out} for a fade-out effect. Default is @code{in}.
478 @item start_sample, ss
479 Specify the number of the start sample for starting to apply the fade
480 effect. Default is 0.
483 Specify the number of samples for which the fade effect has to last. At
484 the end of the fade-in effect the output audio will have the same
485 volume as the input audio, at the end of the fade-out transition
486 the output audio will be silence. Default is 44100.
489 Specify the start time of the fade effect. Default is 0.
490 The value must be specified as a time duration; see
491 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
492 for the accepted syntax.
493 If set this option is used instead of @var{start_sample}.
496 Specify the duration of the fade effect. See
497 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
498 for the accepted syntax.
499 At the end of the fade-in effect the output audio will have the same
500 volume as the input audio, at the end of the fade-out transition
501 the output audio will be silence.
502 By default the duration is determined by @var{nb_samples}.
503 If set this option is used instead of @var{nb_samples}.
506 Set curve for fade transition.
508 It accepts the following values:
511 select triangular, linear slope (default)
513 select quarter of sine wave
515 select half of sine wave
517 select exponential sine wave
521 select inverted parabola
537 Fade in first 15 seconds of audio:
543 Fade out last 25 seconds of a 900 seconds audio:
545 afade=t=out:st=875:d=25
552 Set output format constraints for the input audio. The framework will
553 negotiate the most appropriate format to minimize conversions.
555 It accepts the following parameters:
559 A '|'-separated list of requested sample formats.
562 A '|'-separated list of requested sample rates.
564 @item channel_layouts
565 A '|'-separated list of requested channel layouts.
567 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
568 for the required syntax.
571 If a parameter is omitted, all values are allowed.
573 Force the output to either unsigned 8-bit or signed 16-bit stereo
575 aformat=sample_fmts=u8|s16:channel_layouts=stereo
580 Apply a two-pole all-pass filter with central frequency (in Hz)
581 @var{frequency}, and filter-width @var{width}.
582 An all-pass filter changes the audio's frequency to phase relationship
583 without changing its frequency to amplitude relationship.
585 The filter accepts the following options:
592 Set method to specify band-width of filter.
605 Specify the band-width of a filter in width_type units.
610 Merge two or more audio streams into a single multi-channel stream.
612 The filter accepts the following options:
617 Set the number of inputs. Default is 2.
621 If the channel layouts of the inputs are disjoint, and therefore compatible,
622 the channel layout of the output will be set accordingly and the channels
623 will be reordered as necessary. If the channel layouts of the inputs are not
624 disjoint, the output will have all the channels of the first input then all
625 the channels of the second input, in that order, and the channel layout of
626 the output will be the default value corresponding to the total number of
629 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
630 is FC+BL+BR, then the output will be in 5.1, with the channels in the
631 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
632 first input, b1 is the first channel of the second input).
634 On the other hand, if both input are in stereo, the output channels will be
635 in the default order: a1, a2, b1, b2, and the channel layout will be
636 arbitrarily set to 4.0, which may or may not be the expected value.
638 All inputs must have the same sample rate, and format.
640 If inputs do not have the same duration, the output will stop with the
647 Merge two mono files into a stereo stream:
649 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
653 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
655 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
661 Mixes multiple audio inputs into a single output.
663 Note that this filter only supports float samples (the @var{amerge}
664 and @var{pan} audio filters support many formats). If the @var{amix}
665 input has integer samples then @ref{aresample} will be automatically
666 inserted to perform the conversion to float samples.
670 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
672 will mix 3 input audio streams to a single output with the same duration as the
673 first input and a dropout transition time of 3 seconds.
675 It accepts the following parameters:
679 The number of inputs. If unspecified, it defaults to 2.
682 How to determine the end-of-stream.
686 The duration of the longest input. (default)
689 The duration of the shortest input.
692 The duration of the first input.
696 @item dropout_transition
697 The transition time, in seconds, for volume renormalization when an input
698 stream ends. The default value is 2 seconds.
704 Pass the audio source unchanged to the output.
708 Pad the end of an audio stream with silence.
710 This can be used together with @command{ffmpeg} @option{-shortest} to
711 extend audio streams to the same length as the video stream.
713 A description of the accepted options follows.
717 Set silence packet size. Default value is 4096.
720 Set the number of samples of silence to add to the end. After the
721 value is reached, the stream is terminated. This option is mutually
722 exclusive with @option{whole_len}.
725 Set the minimum total number of samples in the output audio stream. If
726 the value is longer than the input audio length, silence is added to
727 the end, until the value is reached. This option is mutually exclusive
728 with @option{pad_len}.
731 If neither the @option{pad_len} nor the @option{whole_len} option is
732 set, the filter will add silence to the end of the input stream
739 Add 1024 samples of silence to the end of the input:
745 Make sure the audio output will contain at least 10000 samples, pad
746 the input with silence if required:
752 Use @command{ffmpeg} to pad the audio input with silence, so that the
753 video stream will always result the shortest and will be converted
754 until the end in the output file when using the @option{shortest}
757 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
762 Add a phasing effect to the input audio.
764 A phaser filter creates series of peaks and troughs in the frequency spectrum.
765 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
767 A description of the accepted parameters follows.
771 Set input gain. Default is 0.4.
774 Set output gain. Default is 0.74
777 Set delay in milliseconds. Default is 3.0.
780 Set decay. Default is 0.4.
783 Set modulation speed in Hz. Default is 0.5.
786 Set modulation type. Default is triangular.
788 It accepts the following values:
798 Resample the input audio to the specified parameters, using the
799 libswresample library. If none are specified then the filter will
800 automatically convert between its input and output.
802 This filter is also able to stretch/squeeze the audio data to make it match
803 the timestamps or to inject silence / cut out audio to make it match the
804 timestamps, do a combination of both or do neither.
806 The filter accepts the syntax
807 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
808 expresses a sample rate and @var{resampler_options} is a list of
809 @var{key}=@var{value} pairs, separated by ":". See the
810 ffmpeg-resampler manual for the complete list of supported options.
816 Resample the input audio to 44100Hz:
822 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
823 samples per second compensation:
829 @section asetnsamples
831 Set the number of samples per each output audio frame.
833 The last output packet may contain a different number of samples, as
834 the filter will flush all the remaining samples when the input audio
837 The filter accepts the following options:
841 @item nb_out_samples, n
842 Set the number of frames per each output audio frame. The number is
843 intended as the number of samples @emph{per each channel}.
844 Default value is 1024.
847 If set to 1, the filter will pad the last audio frame with zeroes, so
848 that the last frame will contain the same number of samples as the
849 previous ones. Default value is 1.
852 For example, to set the number of per-frame samples to 1234 and
853 disable padding for the last frame, use:
855 asetnsamples=n=1234:p=0
860 Set the sample rate without altering the PCM data.
861 This will result in a change of speed and pitch.
863 The filter accepts the following options:
867 Set the output sample rate. Default is 44100 Hz.
872 Show a line containing various information for each input audio frame.
873 The input audio is not modified.
875 The shown line contains a sequence of key/value pairs of the form
876 @var{key}:@var{value}.
878 The following values are shown in the output:
882 The (sequential) number of the input frame, starting from 0.
885 The presentation timestamp of the input frame, in time base units; the time base
886 depends on the filter input pad, and is usually 1/@var{sample_rate}.
889 The presentation timestamp of the input frame in seconds.
892 position of the frame in the input stream, -1 if this information in
893 unavailable and/or meaningless (for example in case of synthetic audio)
902 The sample rate for the audio frame.
905 The number of samples (per channel) in the frame.
908 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
909 audio, the data is treated as if all the planes were concatenated.
911 @item plane_checksums
912 A list of Adler-32 checksums for each data plane.
917 Display time domain statistical information about the audio channels.
918 Statistics are calculated and displayed for each audio channel and,
919 where applicable, an overall figure is also given.
921 It accepts the following option:
924 Short window length in seconds, used for peak and trough RMS measurement.
925 Default is @code{0.05} (50 miliseconds). Allowed range is @code{[0.1 - 10]}.
928 A description of each shown parameter follows:
932 Mean amplitude displacement from zero.
935 Minimal sample level.
938 Maximal sample level.
942 Standard peak and RMS level measured in dBFS.
946 Peak and trough values for RMS level measured over a short window.
949 Standard ratio of peak to RMS level (note: not in dB).
952 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
953 (i.e. either @var{Min level} or @var{Max level}).
956 Number of occasions (not the number of samples) that the signal attained either
957 @var{Min level} or @var{Max level}.
962 Forward two audio streams and control the order the buffers are forwarded.
964 The filter accepts the following options:
968 Set the expression deciding which stream should be
969 forwarded next: if the result is negative, the first stream is forwarded; if
970 the result is positive or zero, the second stream is forwarded. It can use
971 the following variables:
975 number of buffers forwarded so far on each stream
977 number of samples forwarded so far on each stream
979 current timestamp of each stream
982 The default value is @code{t1-t2}, which means to always forward the stream
983 that has a smaller timestamp.
988 Stress-test @code{amerge} by randomly sending buffers on the wrong
989 input, while avoiding too much of a desynchronization:
991 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
992 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
998 Synchronize audio data with timestamps by squeezing/stretching it and/or
999 dropping samples/adding silence when needed.
1001 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1003 It accepts the following parameters:
1007 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1008 by default. When disabled, time gaps are covered with silence.
1011 The minimum difference between timestamps and audio data (in seconds) to trigger
1012 adding/dropping samples. The default value is 0.1. If you get an imperfect
1013 sync with this filter, try setting this parameter to 0.
1016 The maximum compensation in samples per second. Only relevant with compensate=1.
1017 The default value is 500.
1020 Assume that the first PTS should be this value. The time base is 1 / sample
1021 rate. This allows for padding/trimming at the start of the stream. By default,
1022 no assumption is made about the first frame's expected PTS, so no padding or
1023 trimming is done. For example, this could be set to 0 to pad the beginning with
1024 silence if an audio stream starts after the video stream or to trim any samples
1025 with a negative PTS due to encoder delay.
1033 The filter accepts exactly one parameter, the audio tempo. If not
1034 specified then the filter will assume nominal 1.0 tempo. Tempo must
1035 be in the [0.5, 2.0] range.
1037 @subsection Examples
1041 Slow down audio to 80% tempo:
1047 To speed up audio to 125% tempo:
1055 Trim the input so that the output contains one continuous subpart of the input.
1057 It accepts the following parameters:
1060 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1061 sample with the timestamp @var{start} will be the first sample in the output.
1064 Specify time of the first audio sample that will be dropped, i.e. the
1065 audio sample immediately preceding the one with the timestamp @var{end} will be
1066 the last sample in the output.
1069 Same as @var{start}, except this option sets the start timestamp in samples
1073 Same as @var{end}, except this option sets the end timestamp in samples instead
1077 The maximum duration of the output in seconds.
1080 The number of the first sample that should be output.
1083 The number of the first sample that should be dropped.
1086 @option{start}, @option{end}, and @option{duration} are expressed as time
1087 duration specifications; see
1088 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
1090 Note that the first two sets of the start/end options and the @option{duration}
1091 option look at the frame timestamp, while the _sample options simply count the
1092 samples that pass through the filter. So start/end_pts and start/end_sample will
1093 give different results when the timestamps are wrong, inexact or do not start at
1094 zero. Also note that this filter does not modify the timestamps. If you wish
1095 to have the output timestamps start at zero, insert the asetpts filter after the
1098 If multiple start or end options are set, this filter tries to be greedy and
1099 keep all samples that match at least one of the specified constraints. To keep
1100 only the part that matches all the constraints at once, chain multiple atrim
1103 The defaults are such that all the input is kept. So it is possible to set e.g.
1104 just the end values to keep everything before the specified time.
1109 Drop everything except the second minute of input:
1111 ffmpeg -i INPUT -af atrim=60:120
1115 Keep only the first 1000 samples:
1117 ffmpeg -i INPUT -af atrim=end_sample=1000
1124 Apply a two-pole Butterworth band-pass filter with central
1125 frequency @var{frequency}, and (3dB-point) band-width width.
1126 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1127 instead of the default: constant 0dB peak gain.
1128 The filter roll off at 6dB per octave (20dB per decade).
1130 The filter accepts the following options:
1134 Set the filter's central frequency. Default is @code{3000}.
1137 Constant skirt gain if set to 1. Defaults to 0.
1140 Set method to specify band-width of filter.
1153 Specify the band-width of a filter in width_type units.
1158 Apply a two-pole Butterworth band-reject filter with central
1159 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1160 The filter roll off at 6dB per octave (20dB per decade).
1162 The filter accepts the following options:
1166 Set the filter's central frequency. Default is @code{3000}.
1169 Set method to specify band-width of filter.
1182 Specify the band-width of a filter in width_type units.
1187 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1188 shelving filter with a response similar to that of a standard
1189 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1191 The filter accepts the following options:
1195 Give the gain at 0 Hz. Its useful range is about -20
1196 (for a large cut) to +20 (for a large boost).
1197 Beware of clipping when using a positive gain.
1200 Set the filter's central frequency and so can be used
1201 to extend or reduce the frequency range to be boosted or cut.
1202 The default value is @code{100} Hz.
1205 Set method to specify band-width of filter.
1218 Determine how steep is the filter's shelf transition.
1223 Apply a biquad IIR filter with the given coefficients.
1224 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1225 are the numerator and denominator coefficients respectively.
1228 Bauer stereo to binaural transformation, which improves headphone listening of
1229 stereo audio records.
1231 It accepts the following parameters:
1235 Pre-defined crossfeed level.
1239 Default level (fcut=700, feed=50).
1242 Chu Moy circuit (fcut=700, feed=60).
1245 Jan Meier circuit (fcut=650, feed=95).
1250 Cut frequency (in Hz).
1259 Remap input channels to new locations.
1261 It accepts the following parameters:
1263 @item channel_layout
1264 The channel layout of the output stream.
1267 Map channels from input to output. The argument is a '|'-separated list of
1268 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1269 @var{in_channel} form. @var{in_channel} can be either the name of the input
1270 channel (e.g. FL for front left) or its index in the input channel layout.
1271 @var{out_channel} is the name of the output channel or its index in the output
1272 channel layout. If @var{out_channel} is not given then it is implicitly an
1273 index, starting with zero and increasing by one for each mapping.
1276 If no mapping is present, the filter will implicitly map input channels to
1277 output channels, preserving indices.
1279 For example, assuming a 5.1+downmix input MOV file,
1281 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1283 will create an output WAV file tagged as stereo from the downmix channels of
1286 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1288 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1291 @section channelsplit
1293 Split each channel from an input audio stream into a separate output stream.
1295 It accepts the following parameters:
1297 @item channel_layout
1298 The channel layout of the input stream. The default is "stereo".
1301 For example, assuming a stereo input MP3 file,
1303 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1305 will create an output Matroska file with two audio streams, one containing only
1306 the left channel and the other the right channel.
1308 Split a 5.1 WAV file into per-channel files:
1310 ffmpeg -i in.wav -filter_complex
1311 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1312 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1313 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1318 Compress or expand the audio's dynamic range.
1320 It accepts the following parameters:
1326 A list of times in seconds for each channel over which the instantaneous level
1327 of the input signal is averaged to determine its volume. @var{attacks} refers to
1328 increase of volume and @var{decays} refers to decrease of volume. For most
1329 situations, the attack time (response to the audio getting louder) should be
1330 shorter than the decay time, because the human ear is more sensitive to sudden
1331 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1332 a typical value for decay is 0.8 seconds.
1335 A list of points for the transfer function, specified in dB relative to the
1336 maximum possible signal amplitude. Each key points list must be defined using
1337 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1338 @code{x0/y0 x1/y1 x2/y2 ....}
1340 The input values must be in strictly increasing order but the transfer function
1341 does not have to be monotonically rising. The point @code{0/0} is assumed but
1342 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1343 function are @code{-70/-70|-60/-20}.
1346 Set the curve radius in dB for all joints. It defaults to 0.01.
1349 Set the additional gain in dB to be applied at all points on the transfer
1350 function. This allows for easy adjustment of the overall gain.
1354 Set an initial volume, in dB, to be assumed for each channel when filtering
1355 starts. This permits the user to supply a nominal level initially, so that, for
1356 example, a very large gain is not applied to initial signal levels before the
1357 companding has begun to operate. A typical value for audio which is initially
1358 quiet is -90 dB. It defaults to 0.
1361 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1362 delayed before being fed to the volume adjuster. Specifying a delay
1363 approximately equal to the attack/decay times allows the filter to effectively
1364 operate in predictive rather than reactive mode. It defaults to 0.
1368 @subsection Examples
1372 Make music with both quiet and loud passages suitable for listening to in a
1375 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1379 A noise gate for when the noise is at a lower level than the signal:
1381 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1385 Here is another noise gate, this time for when the noise is at a higher level
1386 than the signal (making it, in some ways, similar to squelch):
1388 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1394 Make audio easier to listen to on headphones.
1396 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1397 so that when listened to on headphones the stereo image is moved from
1398 inside your head (standard for headphones) to outside and in front of
1399 the listener (standard for speakers).
1405 Apply a two-pole peaking equalisation (EQ) filter. With this
1406 filter, the signal-level at and around a selected frequency can
1407 be increased or decreased, whilst (unlike bandpass and bandreject
1408 filters) that at all other frequencies is unchanged.
1410 In order to produce complex equalisation curves, this filter can
1411 be given several times, each with a different central frequency.
1413 The filter accepts the following options:
1417 Set the filter's central frequency in Hz.
1420 Set method to specify band-width of filter.
1433 Specify the band-width of a filter in width_type units.
1436 Set the required gain or attenuation in dB.
1437 Beware of clipping when using a positive gain.
1440 @subsection Examples
1443 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1445 equalizer=f=1000:width_type=h:width=200:g=-10
1449 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1451 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1456 Apply a flanging effect to the audio.
1458 The filter accepts the following options:
1462 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
1465 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
1468 Set percentage regeneneration (delayed signal feedback). Range from -95 to 95.
1472 Set percentage of delayed signal mixed with original. Range from 0 to 100.
1476 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
1479 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
1480 Default value is @var{sinusoidal}.
1483 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
1484 Default value is 25.
1487 Set delay-line interpolation, @var{linear} or @var{quadratic}.
1488 Default is @var{linear}.
1493 Apply a high-pass filter with 3dB point frequency.
1494 The filter can be either single-pole, or double-pole (the default).
1495 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1497 The filter accepts the following options:
1501 Set frequency in Hz. Default is 3000.
1504 Set number of poles. Default is 2.
1507 Set method to specify band-width of filter.
1520 Specify the band-width of a filter in width_type units.
1521 Applies only to double-pole filter.
1522 The default is 0.707q and gives a Butterworth response.
1527 Join multiple input streams into one multi-channel stream.
1529 It accepts the following parameters:
1533 The number of input streams. It defaults to 2.
1535 @item channel_layout
1536 The desired output channel layout. It defaults to stereo.
1539 Map channels from inputs to output. The argument is a '|'-separated list of
1540 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1541 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1542 can be either the name of the input channel (e.g. FL for front left) or its
1543 index in the specified input stream. @var{out_channel} is the name of the output
1547 The filter will attempt to guess the mappings when they are not specified
1548 explicitly. It does so by first trying to find an unused matching input channel
1549 and if that fails it picks the first unused input channel.
1551 Join 3 inputs (with properly set channel layouts):
1553 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1556 Build a 5.1 output from 6 single-channel streams:
1558 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1559 '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'
1565 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1567 To enable compilation of this filter you need to configure FFmpeg with
1568 @code{--enable-ladspa}.
1572 Specifies the name of LADSPA plugin library to load. If the environment
1573 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1574 each one of the directories specified by the colon separated list in
1575 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1576 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1577 @file{/usr/lib/ladspa/}.
1580 Specifies the plugin within the library. Some libraries contain only
1581 one plugin, but others contain many of them. If this is not set filter
1582 will list all available plugins within the specified library.
1585 Set the '|' separated list of controls which are zero or more floating point
1586 values that determine the behavior of the loaded plugin (for example delay,
1588 Controls need to be defined using the following syntax:
1589 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1590 @var{valuei} is the value set on the @var{i}-th control.
1591 If @option{controls} is set to @code{help}, all available controls and
1592 their valid ranges are printed.
1594 @item sample_rate, s
1595 Specify the sample rate, default to 44100. Only used if plugin have
1599 Set the number of samples per channel per each output frame, default
1600 is 1024. Only used if plugin have zero inputs.
1603 Set the minimum duration of the sourced audio. See
1604 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
1605 for the accepted syntax.
1606 Note that the resulting duration may be greater than the specified duration,
1607 as the generated audio is always cut at the end of a complete frame.
1608 If not specified, or the expressed duration is negative, the audio is
1609 supposed to be generated forever.
1610 Only used if plugin have zero inputs.
1614 @subsection Examples
1618 List all available plugins within amp (LADSPA example plugin) library:
1624 List all available controls and their valid ranges for @code{vcf_notch}
1625 plugin from @code{VCF} library:
1627 ladspa=f=vcf:p=vcf_notch:c=help
1631 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1634 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1638 Add reverberation to the audio using TAP-plugins
1639 (Tom's Audio Processing plugins):
1641 ladspa=file=tap_reverb:tap_reverb
1645 Generate white noise, with 0.2 amplitude:
1647 ladspa=file=cmt:noise_source_white:c=c0=.2
1651 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1652 @code{C* Audio Plugin Suite} (CAPS) library:
1654 ladspa=file=caps:Click:c=c1=20'
1658 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1660 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1664 @subsection Commands
1666 This filter supports the following commands:
1669 Modify the @var{N}-th control value.
1671 If the specified value is not valid, it is ignored and prior one is kept.
1676 Apply a low-pass filter with 3dB point frequency.
1677 The filter can be either single-pole or double-pole (the default).
1678 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1680 The filter accepts the following options:
1684 Set frequency in Hz. Default is 500.
1687 Set number of poles. Default is 2.
1690 Set method to specify band-width of filter.
1703 Specify the band-width of a filter in width_type units.
1704 Applies only to double-pole filter.
1705 The default is 0.707q and gives a Butterworth response.
1710 Mix channels with specific gain levels. The filter accepts the output
1711 channel layout followed by a set of channels definitions.
1713 This filter is also designed to remap efficiently the channels of an audio
1716 The filter accepts parameters of the form:
1717 "@var{l}:@var{outdef}:@var{outdef}:..."
1721 output channel layout or number of channels
1724 output channel specification, of the form:
1725 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1728 output channel to define, either a channel name (FL, FR, etc.) or a channel
1729 number (c0, c1, etc.)
1732 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1735 input channel to use, see out_name for details; it is not possible to mix
1736 named and numbered input channels
1739 If the `=' in a channel specification is replaced by `<', then the gains for
1740 that specification will be renormalized so that the total is 1, thus
1741 avoiding clipping noise.
1743 @subsection Mixing examples
1745 For example, if you want to down-mix from stereo to mono, but with a bigger
1746 factor for the left channel:
1748 pan=1:c0=0.9*c0+0.1*c1
1751 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1752 7-channels surround:
1754 pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1757 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1758 that should be preferred (see "-ac" option) unless you have very specific
1761 @subsection Remapping examples
1763 The channel remapping will be effective if, and only if:
1766 @item gain coefficients are zeroes or ones,
1767 @item only one input per channel output,
1770 If all these conditions are satisfied, the filter will notify the user ("Pure
1771 channel mapping detected"), and use an optimized and lossless method to do the
1774 For example, if you have a 5.1 source and want a stereo audio stream by
1775 dropping the extra channels:
1777 pan="stereo: c0=FL : c1=FR"
1780 Given the same source, you can also switch front left and front right channels
1781 and keep the input channel layout:
1783 pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
1786 If the input is a stereo audio stream, you can mute the front left channel (and
1787 still keep the stereo channel layout) with:
1792 Still with a stereo audio stream input, you can copy the right channel in both
1793 front left and right:
1795 pan="stereo: c0=FR : c1=FR"
1800 ReplayGain scanner filter. This filter takes an audio stream as an input and
1801 outputs it unchanged.
1802 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1806 Convert the audio sample format, sample rate and channel layout. It is
1807 not meant to be used directly.
1809 @section silencedetect
1811 Detect silence in an audio stream.
1813 This filter logs a message when it detects that the input audio volume is less
1814 or equal to a noise tolerance value for a duration greater or equal to the
1815 minimum detected noise duration.
1817 The printed times and duration are expressed in seconds.
1819 The filter accepts the following options:
1823 Set silence duration until notification (default is 2 seconds).
1826 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1827 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1830 @subsection Examples
1834 Detect 5 seconds of silence with -50dB noise tolerance:
1836 silencedetect=n=-50dB:d=5
1840 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1841 tolerance in @file{silence.mp3}:
1843 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1847 @section silenceremove
1849 Remove silence from the beginning, middle or end of the audio.
1851 The filter accepts the following options:
1855 This value is used to indicate if audio should be trimmed at beginning of
1856 the audio. A value of zero indicates no silence should be trimmed from the
1857 beginning. When specifying a non-zero value, it trims audio up until it
1858 finds non-silence. Normally, when trimming silence from beginning of audio
1859 the @var{start_periods} will be @code{1} but it can be increased to higher
1860 values to trim all audio up to specific count of non-silence periods.
1861 Default value is @code{0}.
1863 @item start_duration
1864 Specify the amount of time that non-silence must be detected before it stops
1865 trimming audio. By increasing the duration, bursts of noises can be treated
1866 as silence and trimmed off. Default value is @code{0}.
1868 @item start_threshold
1869 This indicates what sample value should be treated as silence. For digital
1870 audio, a value of @code{0} may be fine but for audio recorded from analog,
1871 you may wish to increase the value to account for background noise.
1872 Can be specified in dB (in case "dB" is appended to the specified value)
1873 or amplitude ratio. Default value is @code{0}.
1876 Set the count for trimming silence from the end of audio.
1877 To remove silence from the middle of a file, specify a @var{stop_periods}
1878 that is negative. This value is then threated as a positive value and is
1879 used to indicate the effect should restart processing as specified by
1880 @var{start_periods}, making it suitable for removing periods of silence
1881 in the middle of the audio.
1882 Default value is @code{0}.
1885 Specify a duration of silence that must exist before audio is not copied any
1886 more. By specifying a higher duration, silence that is wanted can be left in
1888 Default value is @code{0}.
1890 @item stop_threshold
1891 This is the same as @option{start_threshold} but for trimming silence from
1893 Can be specified in dB (in case "dB" is appended to the specified value)
1894 or amplitude ratio. Default value is @code{0}.
1897 This indicate that @var{stop_duration} length of audio should be left intact
1898 at the beginning of each period of silence.
1899 For example, if you want to remove long pauses between words but do not want
1900 to remove the pauses completely. Default value is @code{0}.
1904 @subsection Examples
1908 The following example shows how this filter can be used to start a recording
1909 that does not contain the delay at the start which usually occurs between
1910 pressing the record button and the start of the performance:
1912 silenceremove=1:5:0.02
1918 Boost or cut treble (upper) frequencies of the audio using a two-pole
1919 shelving filter with a response similar to that of a standard
1920 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1922 The filter accepts the following options:
1926 Give the gain at whichever is the lower of ~22 kHz and the
1927 Nyquist frequency. Its useful range is about -20 (for a large cut)
1928 to +20 (for a large boost). Beware of clipping when using a positive gain.
1931 Set the filter's central frequency and so can be used
1932 to extend or reduce the frequency range to be boosted or cut.
1933 The default value is @code{3000} Hz.
1936 Set method to specify band-width of filter.
1949 Determine how steep is the filter's shelf transition.
1954 Adjust the input audio volume.
1956 It accepts the following parameters:
1960 Set audio volume expression.
1962 Output values are clipped to the maximum value.
1964 The output audio volume is given by the relation:
1966 @var{output_volume} = @var{volume} * @var{input_volume}
1969 The default value for @var{volume} is "1.0".
1972 This parameter represents the mathematical precision.
1974 It determines which input sample formats will be allowed, which affects the
1975 precision of the volume scaling.
1979 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
1981 32-bit floating-point; this limits input sample format to FLT. (default)
1983 64-bit floating-point; this limits input sample format to DBL.
1987 Choose the behaviour on encountering ReplayGain side data in input frames.
1991 Remove ReplayGain side data, ignoring its contents (the default).
1994 Ignore ReplayGain side data, but leave it in the frame.
1997 Prefer the track gain, if present.
2000 Prefer the album gain, if present.
2003 @item replaygain_preamp
2004 Pre-amplification gain in dB to apply to the selected replaygain gain.
2006 Default value for @var{replaygain_preamp} is 0.0.
2009 Set when the volume expression is evaluated.
2011 It accepts the following values:
2014 only evaluate expression once during the filter initialization, or
2015 when the @samp{volume} command is sent
2018 evaluate expression for each incoming frame
2021 Default value is @samp{once}.
2024 The volume expression can contain the following parameters.
2028 frame number (starting at zero)
2031 @item nb_consumed_samples
2032 number of samples consumed by the filter
2034 number of samples in the current frame
2036 original frame position in the file
2042 PTS at start of stream
2044 time at start of stream
2050 last set volume value
2053 Note that when @option{eval} is set to @samp{once} only the
2054 @var{sample_rate} and @var{tb} variables are available, all other
2055 variables will evaluate to NAN.
2057 @subsection Commands
2059 This filter supports the following commands:
2062 Modify the volume expression.
2063 The command accepts the same syntax of the corresponding option.
2065 If the specified expression is not valid, it is kept at its current
2067 @item replaygain_noclip
2068 Prevent clipping by limiting the gain applied.
2070 Default value for @var{replaygain_noclip} is 1.
2074 @subsection Examples
2078 Halve the input audio volume:
2082 volume=volume=-6.0206dB
2085 In all the above example the named key for @option{volume} can be
2086 omitted, for example like in:
2092 Increase input audio power by 6 decibels using fixed-point precision:
2094 volume=volume=6dB:precision=fixed
2098 Fade volume after time 10 with an annihilation period of 5 seconds:
2100 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
2104 @section volumedetect
2106 Detect the volume of the input video.
2108 The filter has no parameters. The input is not modified. Statistics about
2109 the volume will be printed in the log when the input stream end is reached.
2111 In particular it will show the mean volume (root mean square), maximum
2112 volume (on a per-sample basis), and the beginning of a histogram of the
2113 registered volume values (from the maximum value to a cumulated 1/1000 of
2116 All volumes are in decibels relative to the maximum PCM value.
2118 @subsection Examples
2120 Here is an excerpt of the output:
2122 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2123 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2124 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2125 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2126 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2127 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2128 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2129 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2130 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2136 The mean square energy is approximately -27 dB, or 10^-2.7.
2138 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2140 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2143 In other words, raising the volume by +4 dB does not cause any clipping,
2144 raising it by +5 dB causes clipping for 6 samples, etc.
2146 @c man end AUDIO FILTERS
2148 @chapter Audio Sources
2149 @c man begin AUDIO SOURCES
2151 Below is a description of the currently available audio sources.
2155 Buffer audio frames, and make them available to the filter chain.
2157 This source is mainly intended for a programmatic use, in particular
2158 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2160 It accepts the following parameters:
2164 The timebase which will be used for timestamps of submitted frames. It must be
2165 either a floating-point number or in @var{numerator}/@var{denominator} form.
2168 The sample rate of the incoming audio buffers.
2171 The sample format of the incoming audio buffers.
2172 Either a sample format name or its corresponging integer representation from
2173 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2175 @item channel_layout
2176 The channel layout of the incoming audio buffers.
2177 Either a channel layout name from channel_layout_map in
2178 @file{libavutil/channel_layout.c} or its corresponding integer representation
2179 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2182 The number of channels of the incoming audio buffers.
2183 If both @var{channels} and @var{channel_layout} are specified, then they
2188 @subsection Examples
2191 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2194 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2195 Since the sample format with name "s16p" corresponds to the number
2196 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2199 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2204 Generate an audio signal specified by an expression.
2206 This source accepts in input one or more expressions (one for each
2207 channel), which are evaluated and used to generate a corresponding
2210 This source accepts the following options:
2214 Set the '|'-separated expressions list for each separate channel. In case the
2215 @option{channel_layout} option is not specified, the selected channel layout
2216 depends on the number of provided expressions. Otherwise the last
2217 specified expression is applied to the remaining output channels.
2219 @item channel_layout, c
2220 Set the channel layout. The number of channels in the specified layout
2221 must be equal to the number of specified expressions.
2224 Set the minimum duration of the sourced audio. See
2225 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
2226 for the accepted syntax.
2227 Note that the resulting duration may be greater than the specified
2228 duration, as the generated audio is always cut at the end of a
2231 If not specified, or the expressed duration is negative, the audio is
2232 supposed to be generated forever.
2235 Set the number of samples per channel per each output frame,
2238 @item sample_rate, s
2239 Specify the sample rate, default to 44100.
2242 Each expression in @var{exprs} can contain the following constants:
2246 number of the evaluated sample, starting from 0
2249 time of the evaluated sample expressed in seconds, starting from 0
2256 @subsection Examples
2266 Generate a sin signal with frequency of 440 Hz, set sample rate to
2269 aevalsrc="sin(440*2*PI*t):s=8000"
2273 Generate a two channels signal, specify the channel layout (Front
2274 Center + Back Center) explicitly:
2276 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2280 Generate white noise:
2282 aevalsrc="-2+random(0)"
2286 Generate an amplitude modulated signal:
2288 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2292 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2294 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2301 The null audio source, return unprocessed audio frames. It is mainly useful
2302 as a template and to be employed in analysis / debugging tools, or as
2303 the source for filters which ignore the input data (for example the sox
2306 This source accepts the following options:
2310 @item channel_layout, cl
2312 Specifies the channel layout, and can be either an integer or a string
2313 representing a channel layout. The default value of @var{channel_layout}
2316 Check the channel_layout_map definition in
2317 @file{libavutil/channel_layout.c} for the mapping between strings and
2318 channel layout values.
2320 @item sample_rate, r
2321 Specifies the sample rate, and defaults to 44100.
2324 Set the number of samples per requested frames.
2328 @subsection Examples
2332 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2334 anullsrc=r=48000:cl=4
2338 Do the same operation with a more obvious syntax:
2340 anullsrc=r=48000:cl=mono
2344 All the parameters need to be explicitly defined.
2348 Synthesize a voice utterance using the libflite library.
2350 To enable compilation of this filter you need to configure FFmpeg with
2351 @code{--enable-libflite}.
2353 Note that the flite library is not thread-safe.
2355 The filter accepts the following options:
2360 If set to 1, list the names of the available voices and exit
2361 immediately. Default value is 0.
2364 Set the maximum number of samples per frame. Default value is 512.
2367 Set the filename containing the text to speak.
2370 Set the text to speak.
2373 Set the voice to use for the speech synthesis. Default value is
2374 @code{kal}. See also the @var{list_voices} option.
2377 @subsection Examples
2381 Read from file @file{speech.txt}, and synthetize the text using the
2382 standard flite voice:
2384 flite=textfile=speech.txt
2388 Read the specified text selecting the @code{slt} voice:
2390 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2394 Input text to ffmpeg:
2396 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2400 Make @file{ffplay} speak the specified text, using @code{flite} and
2401 the @code{lavfi} device:
2403 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2407 For more information about libflite, check:
2408 @url{http://www.speech.cs.cmu.edu/flite/}
2412 Generate an audio signal made of a sine wave with amplitude 1/8.
2414 The audio signal is bit-exact.
2416 The filter accepts the following options:
2421 Set the carrier frequency. Default is 440 Hz.
2423 @item beep_factor, b
2424 Enable a periodic beep every second with frequency @var{beep_factor} times
2425 the carrier frequency. Default is 0, meaning the beep is disabled.
2427 @item sample_rate, r
2428 Specify the sample rate, default is 44100.
2431 Specify the duration of the generated audio stream.
2433 @item samples_per_frame
2434 Set the number of samples per output frame, default is 1024.
2437 @subsection Examples
2442 Generate a simple 440 Hz sine wave:
2448 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2452 sine=frequency=220:beep_factor=4:duration=5
2457 @c man end AUDIO SOURCES
2459 @chapter Audio Sinks
2460 @c man begin AUDIO SINKS
2462 Below is a description of the currently available audio sinks.
2464 @section abuffersink
2466 Buffer audio frames, and make them available to the end of filter chain.
2468 This sink is mainly intended for programmatic use, in particular
2469 through the interface defined in @file{libavfilter/buffersink.h}
2470 or the options system.
2472 It accepts a pointer to an AVABufferSinkContext structure, which
2473 defines the incoming buffers' formats, to be passed as the opaque
2474 parameter to @code{avfilter_init_filter} for initialization.
2477 Null audio sink; do absolutely nothing with the input audio. It is
2478 mainly useful as a template and for use in analysis / debugging
2481 @c man end AUDIO SINKS
2483 @chapter Video Filters
2484 @c man begin VIDEO FILTERS
2486 When you configure your FFmpeg build, you can disable any of the
2487 existing filters using @code{--disable-filters}.
2488 The configure output will show the video filters included in your
2491 Below is a description of the currently available video filters.
2493 @section alphaextract
2495 Extract the alpha component from the input as a grayscale video. This
2496 is especially useful with the @var{alphamerge} filter.
2500 Add or replace the alpha component of the primary input with the
2501 grayscale value of a second input. This is intended for use with
2502 @var{alphaextract} to allow the transmission or storage of frame
2503 sequences that have alpha in a format that doesn't support an alpha
2506 For example, to reconstruct full frames from a normal YUV-encoded video
2507 and a separate video created with @var{alphaextract}, you might use:
2509 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2512 Since this filter is designed for reconstruction, it operates on frame
2513 sequences without considering timestamps, and terminates when either
2514 input reaches end of stream. This will cause problems if your encoding
2515 pipeline drops frames. If you're trying to apply an image as an
2516 overlay to a video stream, consider the @var{overlay} filter instead.
2520 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2521 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2522 Substation Alpha) subtitles files.
2524 This filter accepts the following option in addition to the common options from
2525 the @ref{subtitles} filter:
2529 Set the shaping engine
2531 Available values are:
2534 The default libass shaping engine, which is the best available.
2536 Fast, font-agnostic shaper that can do only substitutions
2538 Slower shaper using OpenType for substitutions and positioning
2541 The default is @code{auto}.
2546 Compute the bounding box for the non-black pixels in the input frame
2549 This filter computes the bounding box containing all the pixels with a
2550 luminance value greater than the minimum allowed value.
2551 The parameters describing the bounding box are printed on the filter
2554 The filter accepts the following option:
2558 Set the minimal luminance value. Default is @code{16}.
2561 @section blackdetect
2563 Detect video intervals that are (almost) completely black. Can be
2564 useful to detect chapter transitions, commercials, or invalid
2565 recordings. Output lines contains the time for the start, end and
2566 duration of the detected black interval expressed in seconds.
2568 In order to display the output lines, you need to set the loglevel at
2569 least to the AV_LOG_INFO value.
2571 The filter accepts the following options:
2574 @item black_min_duration, d
2575 Set the minimum detected black duration expressed in seconds. It must
2576 be a non-negative floating point number.
2578 Default value is 2.0.
2580 @item picture_black_ratio_th, pic_th
2581 Set the threshold for considering a picture "black".
2582 Express the minimum value for the ratio:
2584 @var{nb_black_pixels} / @var{nb_pixels}
2587 for which a picture is considered black.
2588 Default value is 0.98.
2590 @item pixel_black_th, pix_th
2591 Set the threshold for considering a pixel "black".
2593 The threshold expresses the maximum pixel luminance value for which a
2594 pixel is considered "black". The provided value is scaled according to
2595 the following equation:
2597 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2600 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2601 the input video format, the range is [0-255] for YUV full-range
2602 formats and [16-235] for YUV non full-range formats.
2604 Default value is 0.10.
2607 The following example sets the maximum pixel threshold to the minimum
2608 value, and detects only black intervals of 2 or more seconds:
2610 blackdetect=d=2:pix_th=0.00
2615 Detect frames that are (almost) completely black. Can be useful to
2616 detect chapter transitions or commercials. Output lines consist of
2617 the frame number of the detected frame, the percentage of blackness,
2618 the position in the file if known or -1 and the timestamp in seconds.
2620 In order to display the output lines, you need to set the loglevel at
2621 least to the AV_LOG_INFO value.
2623 It accepts the following parameters:
2628 The percentage of the pixels that have to be below the threshold; it defaults to
2631 @item threshold, thresh
2632 The threshold below which a pixel value is considered black; it defaults to
2639 Blend two video frames into each other.
2641 It takes two input streams and outputs one stream, the first input is the
2642 "top" layer and second input is "bottom" layer.
2643 Output terminates when shortest input terminates.
2645 A description of the accepted options follows.
2653 Set blend mode for specific pixel component or all pixel components in case
2654 of @var{all_mode}. Default value is @code{normal}.
2656 Available values for component modes are:
2689 Set blend opacity for specific pixel component or all pixel components in case
2690 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2697 Set blend expression for specific pixel component or all pixel components in case
2698 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2700 The expressions can use the following variables:
2704 The sequential number of the filtered frame, starting from @code{0}.
2708 the coordinates of the current sample
2712 the width and height of currently filtered plane
2716 Width and height scale depending on the currently filtered plane. It is the
2717 ratio between the corresponding luma plane number of pixels and the current
2718 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2719 @code{0.5,0.5} for chroma planes.
2722 Time of the current frame, expressed in seconds.
2725 Value of pixel component at current location for first video frame (top layer).
2728 Value of pixel component at current location for second video frame (bottom layer).
2732 Force termination when the shortest input terminates. Default is @code{0}.
2734 Continue applying the last bottom frame after the end of the stream. A value of
2735 @code{0} disable the filter after the last frame of the bottom layer is reached.
2736 Default is @code{1}.
2739 @subsection Examples
2743 Apply transition from bottom layer to top layer in first 10 seconds:
2745 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2749 Apply 1x1 checkerboard effect:
2751 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2755 Apply uncover left effect:
2757 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2761 Apply uncover down effect:
2763 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2767 Apply uncover up-left effect:
2769 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2775 Apply a boxblur algorithm to the input video.
2777 It accepts the following parameters:
2781 @item luma_radius, lr
2782 @item luma_power, lp
2783 @item chroma_radius, cr
2784 @item chroma_power, cp
2785 @item alpha_radius, ar
2786 @item alpha_power, ap
2790 A description of the accepted options follows.
2793 @item luma_radius, lr
2794 @item chroma_radius, cr
2795 @item alpha_radius, ar
2796 Set an expression for the box radius in pixels used for blurring the
2797 corresponding input plane.
2799 The radius value must be a non-negative number, and must not be
2800 greater than the value of the expression @code{min(w,h)/2} for the
2801 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2804 Default value for @option{luma_radius} is "2". If not specified,
2805 @option{chroma_radius} and @option{alpha_radius} default to the
2806 corresponding value set for @option{luma_radius}.
2808 The expressions can contain the following constants:
2812 The input width and height in pixels.
2816 The input chroma image width and height in pixels.
2820 The horizontal and vertical chroma subsample values. For example, for the
2821 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
2824 @item luma_power, lp
2825 @item chroma_power, cp
2826 @item alpha_power, ap
2827 Specify how many times the boxblur filter is applied to the
2828 corresponding plane.
2830 Default value for @option{luma_power} is 2. If not specified,
2831 @option{chroma_power} and @option{alpha_power} default to the
2832 corresponding value set for @option{luma_power}.
2834 A value of 0 will disable the effect.
2837 @subsection Examples
2841 Apply a boxblur filter with the luma, chroma, and alpha radii
2844 boxblur=luma_radius=2:luma_power=1
2849 Set the luma radius to 2, and alpha and chroma radius to 0:
2851 boxblur=2:1:cr=0:ar=0
2855 Set the luma and chroma radii to a fraction of the video dimension:
2857 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2863 Visualize information exported by some codecs.
2865 Some codecs can export information through frames using side-data or other
2866 means. For example, some MPEG based codecs export motion vectors through the
2867 @var{export_mvs} flag in the codec @option{flags2} option.
2869 The filter accepts the following option:
2873 Set motion vectors to visualize.
2875 Available flags for @var{mv} are:
2879 forward predicted MVs of P-frames
2881 forward predicted MVs of B-frames
2883 backward predicted MVs of B-frames
2887 @subsection Examples
2891 Visualizes multi-directionals MVs from P and B-Frames using @command{ffplay}:
2893 ffplay -flags2 +export_mvs input.mpg -vf codecview=mv=pf+bf+bb
2897 @section colorbalance
2898 Modify intensity of primary colors (red, green and blue) of input frames.
2900 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2901 regions for the red-cyan, green-magenta or blue-yellow balance.
2903 A positive adjustment value shifts the balance towards the primary color, a negative
2904 value towards the complementary color.
2906 The filter accepts the following options:
2912 Adjust red, green and blue shadows (darkest pixels).
2917 Adjust red, green and blue midtones (medium pixels).
2922 Adjust red, green and blue highlights (brightest pixels).
2924 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2927 @subsection Examples
2931 Add red color cast to shadows:
2937 @section colorchannelmixer
2939 Adjust video input frames by re-mixing color channels.
2941 This filter modifies a color channel by adding the values associated to
2942 the other channels of the same pixels. For example if the value to
2943 modify is red, the output value will be:
2945 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2948 The filter accepts the following options:
2955 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2956 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2962 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2963 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2969 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2970 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2976 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2977 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2979 Allowed ranges for options are @code{[-2.0, 2.0]}.
2982 @subsection Examples
2986 Convert source to grayscale:
2988 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2991 Simulate sepia tones:
2993 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
2997 @section colormatrix
2999 Convert color matrix.
3001 The filter accepts the following options:
3006 Specify the source and destination color matrix. Both values must be
3009 The accepted values are:
3025 For example to convert from BT.601 to SMPTE-240M, use the command:
3027 colormatrix=bt601:smpte240m
3032 Copy the input source unchanged to the output. This is mainly useful for
3037 Crop the input video to given dimensions.
3039 It accepts the following parameters:
3043 The width of the output video. It defaults to @code{iw}.
3044 This expression is evaluated only once during the filter
3048 The height of the output video. It defaults to @code{ih}.
3049 This expression is evaluated only once during the filter
3053 The horizontal position, in the input video, of the left edge of the output
3054 video. It defaults to @code{(in_w-out_w)/2}.
3055 This expression is evaluated per-frame.
3058 The vertical position, in the input video, of the top edge of the output video.
3059 It defaults to @code{(in_h-out_h)/2}.
3060 This expression is evaluated per-frame.
3063 If set to 1 will force the output display aspect ratio
3064 to be the same of the input, by changing the output sample aspect
3065 ratio. It defaults to 0.
3068 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
3069 expressions containing the following constants:
3074 The computed values for @var{x} and @var{y}. They are evaluated for
3079 The input width and height.
3083 These are the same as @var{in_w} and @var{in_h}.
3087 The output (cropped) width and height.
3091 These are the same as @var{out_w} and @var{out_h}.
3094 same as @var{iw} / @var{ih}
3097 input sample aspect ratio
3100 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
3104 horizontal and vertical chroma subsample values. For example for the
3105 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3108 The number of the input frame, starting from 0.
3111 the position in the file of the input frame, NAN if unknown
3114 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
3118 The expression for @var{out_w} may depend on the value of @var{out_h},
3119 and the expression for @var{out_h} may depend on @var{out_w}, but they
3120 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
3121 evaluated after @var{out_w} and @var{out_h}.
3123 The @var{x} and @var{y} parameters specify the expressions for the
3124 position of the top-left corner of the output (non-cropped) area. They
3125 are evaluated for each frame. If the evaluated value is not valid, it
3126 is approximated to the nearest valid value.
3128 The expression for @var{x} may depend on @var{y}, and the expression
3129 for @var{y} may depend on @var{x}.
3131 @subsection Examples
3135 Crop area with size 100x100 at position (12,34).
3140 Using named options, the example above becomes:
3142 crop=w=100:h=100:x=12:y=34
3146 Crop the central input area with size 100x100:
3152 Crop the central input area with size 2/3 of the input video:
3154 crop=2/3*in_w:2/3*in_h
3158 Crop the input video central square:
3165 Delimit the rectangle with the top-left corner placed at position
3166 100:100 and the right-bottom corner corresponding to the right-bottom
3167 corner of the input image.
3169 crop=in_w-100:in_h-100:100:100
3173 Crop 10 pixels from the left and right borders, and 20 pixels from
3174 the top and bottom borders
3176 crop=in_w-2*10:in_h-2*20
3180 Keep only the bottom right quarter of the input image:
3182 crop=in_w/2:in_h/2:in_w/2:in_h/2
3186 Crop height for getting Greek harmony:
3188 crop=in_w:1/PHI*in_w
3192 Appply trembling effect:
3194 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)
3198 Apply erratic camera effect depending on timestamp:
3200 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)"
3204 Set x depending on the value of y:
3206 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3212 Auto-detect the crop size.
3214 It calculates the necessary cropping parameters and prints the
3215 recommended parameters via the logging system. The detected dimensions
3216 correspond to the non-black area of the input video.
3218 It accepts the following parameters:
3223 Set higher black value threshold, which can be optionally specified
3224 from nothing (0) to everything (255). An intensity value greater
3225 to the set value is considered non-black. It defaults to 24.
3228 The value which the width/height should be divisible by. It defaults to
3229 16. The offset is automatically adjusted to center the video. Use 2 to
3230 get only even dimensions (needed for 4:2:2 video). 16 is best when
3231 encoding to most video codecs.
3233 @item reset_count, reset
3234 Set the counter that determines after how many frames cropdetect will
3235 reset the previously detected largest video area and start over to
3236 detect the current optimal crop area. Default value is 0.
3238 This can be useful when channel logos distort the video area. 0
3239 indicates 'never reset', and returns the largest area encountered during
3246 Apply color adjustments using curves.
3248 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3249 component (red, green and blue) has its values defined by @var{N} key points
3250 tied from each other using a smooth curve. The x-axis represents the pixel
3251 values from the input frame, and the y-axis the new pixel values to be set for
3254 By default, a component curve is defined by the two points @var{(0;0)} and
3255 @var{(1;1)}. This creates a straight line where each original pixel value is
3256 "adjusted" to its own value, which means no change to the image.
3258 The filter allows you to redefine these two points and add some more. A new
3259 curve (using a natural cubic spline interpolation) will be define to pass
3260 smoothly through all these new coordinates. The new defined points needs to be
3261 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3262 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3263 the vector spaces, the values will be clipped accordingly.
3265 If there is no key point defined in @code{x=0}, the filter will automatically
3266 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3267 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3269 The filter accepts the following options:
3273 Select one of the available color presets. This option can be used in addition
3274 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3275 options takes priority on the preset values.
3276 Available presets are:
3279 @item color_negative
3282 @item increase_contrast
3284 @item linear_contrast
3285 @item medium_contrast
3287 @item strong_contrast
3290 Default is @code{none}.
3292 Set the master key points. These points will define a second pass mapping. It
3293 is sometimes called a "luminance" or "value" mapping. It can be used with
3294 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3295 post-processing LUT.
3297 Set the key points for the red component.
3299 Set the key points for the green component.
3301 Set the key points for the blue component.
3303 Set the key points for all components (not including master).
3304 Can be used in addition to the other key points component
3305 options. In this case, the unset component(s) will fallback on this
3306 @option{all} setting.
3308 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3311 To avoid some filtergraph syntax conflicts, each key points list need to be
3312 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3314 @subsection Examples
3318 Increase slightly the middle level of blue:
3320 curves=blue='0.5/0.58'
3326 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3328 Here we obtain the following coordinates for each components:
3331 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3333 @code{(0;0) (0.50;0.48) (1;1)}
3335 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3339 The previous example can also be achieved with the associated built-in preset:
3341 curves=preset=vintage
3351 Use a Photoshop preset and redefine the points of the green component:
3353 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3359 Denoise frames using 2D DCT (frequency domain filtering).
3361 This filter is not designed for real time.
3363 The filter accepts the following options:
3367 Set the noise sigma constant.
3369 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3370 coefficient (absolute value) below this threshold with be dropped.
3372 If you need a more advanced filtering, see @option{expr}.
3374 Default is @code{0}.
3377 Set number overlapping pixels for each block. Since the filter can be slow, you
3378 may want to reduce this value, at the cost of a less effective filter and the
3379 risk of various artefacts.
3381 If the overlapping value doesn't allow to process the whole input width or
3382 height, a warning will be displayed and according borders won't be denoised.
3384 Default value is @var{blocksize}-1, which is the best possible setting.
3387 Set the coefficient factor expression.
3389 For each coefficient of a DCT block, this expression will be evaluated as a
3390 multiplier value for the coefficient.
3392 If this is option is set, the @option{sigma} option will be ignored.
3394 The absolute value of the coefficient can be accessed through the @var{c}
3398 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
3399 @var{blocksize}, which is the width and height of the processed blocks.
3401 The default value is @var{3} (8x8) and can be raised to @var{4} for a
3402 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
3403 on the speed processing. Also, a larger block size does not necessarily means a
3407 @subsection Examples
3409 Apply a denoise with a @option{sigma} of @code{4.5}:
3414 The same operation can be achieved using the expression system:
3416 dctdnoiz=e='gte(c, 4.5*3)'
3419 Violent denoise using a block size of @code{16x16}:
3427 Drop duplicated frames at regular intervals.
3429 The filter accepts the following options:
3433 Set the number of frames from which one will be dropped. Setting this to
3434 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3435 Default is @code{5}.
3438 Set the threshold for duplicate detection. If the difference metric for a frame
3439 is less than or equal to this value, then it is declared as duplicate. Default
3443 Set scene change threshold. Default is @code{15}.
3447 Set the size of the x and y-axis blocks used during metric calculations.
3448 Larger blocks give better noise suppression, but also give worse detection of
3449 small movements. Must be a power of two. Default is @code{32}.
3452 Mark main input as a pre-processed input and activate clean source input
3453 stream. This allows the input to be pre-processed with various filters to help
3454 the metrics calculation while keeping the frame selection lossless. When set to
3455 @code{1}, the first stream is for the pre-processed input, and the second
3456 stream is the clean source from where the kept frames are chosen. Default is
3460 Set whether or not chroma is considered in the metric calculations. Default is
3466 Remove judder produced by partially interlaced telecined content.
3468 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3469 source was partially telecined content then the output of @code{pullup,dejudder}
3470 will have a variable frame rate. May change the recorded frame rate of the
3471 container. Aside from that change, this filter will not affect constant frame
3474 The option available in this filter is:
3478 Specify the length of the window over which the judder repeats.
3480 Accepts any integer greater than 1. Useful values are:
3484 If the original was telecined from 24 to 30 fps (Film to NTSC).
3487 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3490 If a mixture of the two.
3493 The default is @samp{4}.
3498 Suppress a TV station logo by a simple interpolation of the surrounding
3499 pixels. Just set a rectangle covering the logo and watch it disappear
3500 (and sometimes something even uglier appear - your mileage may vary).
3502 It accepts the following parameters:
3507 Specify the top left corner coordinates of the logo. They must be
3512 Specify the width and height of the logo to clear. They must be
3516 Specify the thickness of the fuzzy edge of the rectangle (added to
3517 @var{w} and @var{h}). The default value is 4.
3520 When set to 1, a green rectangle is drawn on the screen to simplify
3521 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3522 The default value is 0.
3524 The rectangle is drawn on the outermost pixels which will be (partly)
3525 replaced with interpolated values. The values of the next pixels
3526 immediately outside this rectangle in each direction will be used to
3527 compute the interpolated pixel values inside the rectangle.
3531 @subsection Examples
3535 Set a rectangle covering the area with top left corner coordinates 0,0
3536 and size 100x77, and a band of size 10:
3538 delogo=x=0:y=0:w=100:h=77:band=10
3545 Attempt to fix small changes in horizontal and/or vertical shift. This
3546 filter helps remove camera shake from hand-holding a camera, bumping a
3547 tripod, moving on a vehicle, etc.
3549 The filter accepts the following options:
3557 Specify a rectangular area where to limit the search for motion
3559 If desired the search for motion vectors can be limited to a
3560 rectangular area of the frame defined by its top left corner, width
3561 and height. These parameters have the same meaning as the drawbox
3562 filter which can be used to visualise the position of the bounding
3565 This is useful when simultaneous movement of subjects within the frame
3566 might be confused for camera motion by the motion vector search.
3568 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3569 then the full frame is used. This allows later options to be set
3570 without specifying the bounding box for the motion vector search.
3572 Default - search the whole frame.
3576 Specify the maximum extent of movement in x and y directions in the
3577 range 0-64 pixels. Default 16.
3580 Specify how to generate pixels to fill blanks at the edge of the
3581 frame. Available values are:
3584 Fill zeroes at blank locations
3586 Original image at blank locations
3588 Extruded edge value at blank locations
3590 Mirrored edge at blank locations
3592 Default value is @samp{mirror}.
3595 Specify the blocksize to use for motion search. Range 4-128 pixels,
3599 Specify the contrast threshold for blocks. Only blocks with more than
3600 the specified contrast (difference between darkest and lightest
3601 pixels) will be considered. Range 1-255, default 125.
3604 Specify the search strategy. Available values are:
3607 Set exhaustive search
3609 Set less exhaustive search.
3611 Default value is @samp{exhaustive}.
3614 If set then a detailed log of the motion search is written to the
3618 If set to 1, specify using OpenCL capabilities, only available if
3619 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3625 Draw a colored box on the input image.
3627 It accepts the following parameters:
3632 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3636 The expressions which specify the width and height of the box; if 0 they are interpreted as
3637 the input width and height. It defaults to 0.
3640 Specify the color of the box to write. For the general syntax of this option,
3641 check the "Color" section in the ffmpeg-utils manual. If the special
3642 value @code{invert} is used, the box edge color is the same as the
3643 video with inverted luma.
3646 The expression which sets the thickness of the box edge. Default value is @code{3}.
3648 See below for the list of accepted constants.
3651 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3652 following constants:
3656 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3660 horizontal and vertical chroma subsample values. For example for the
3661 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3665 The input width and height.
3668 The input sample aspect ratio.
3672 The x and y offset coordinates where the box is drawn.
3676 The width and height of the drawn box.
3679 The thickness of the drawn box.
3681 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3682 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3686 @subsection Examples
3690 Draw a black box around the edge of the input image:
3696 Draw a box with color red and an opacity of 50%:
3698 drawbox=10:20:200:60:red@@0.5
3701 The previous example can be specified as:
3703 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3707 Fill the box with pink color:
3709 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3713 Draw a 2-pixel red 2.40:1 mask:
3715 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
3721 Draw a grid on the input image.
3723 It accepts the following parameters:
3728 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3732 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3733 input width and height, respectively, minus @code{thickness}, so image gets
3734 framed. Default to 0.
3737 Specify the color of the grid. For the general syntax of this option,
3738 check the "Color" section in the ffmpeg-utils manual. If the special
3739 value @code{invert} is used, the grid color is the same as the
3740 video with inverted luma.
3743 The expression which sets the thickness of the grid line. Default value is @code{1}.
3745 See below for the list of accepted constants.
3748 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3749 following constants:
3753 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3757 horizontal and vertical chroma subsample values. For example for the
3758 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3762 The input grid cell width and height.
3765 The input sample aspect ratio.
3769 The x and y coordinates of some point of grid intersection (meant to configure offset).
3773 The width and height of the drawn cell.
3776 The thickness of the drawn cell.
3778 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3779 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3783 @subsection Examples
3787 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3789 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3793 Draw a white 3x3 grid with an opacity of 50%:
3795 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3802 Draw a text string or text from a specified file on top of a video, using the
3803 libfreetype library.
3805 To enable compilation of this filter, you need to configure FFmpeg with
3806 @code{--enable-libfreetype}.
3807 To enable default font fallback and the @var{font} option you need to
3808 configure FFmpeg with @code{--enable-libfontconfig}.
3809 To enable the @var{text_shaping} option, you need to configure FFmpeg with
3810 @code{--enable-libfribidi}.
3814 It accepts the following parameters:
3819 Used to draw a box around text using the background color.
3820 The value must be either 1 (enable) or 0 (disable).
3821 The default value of @var{box} is 0.
3824 The color to be used for drawing box around text. For the syntax of this
3825 option, check the "Color" section in the ffmpeg-utils manual.
3827 The default value of @var{boxcolor} is "white".
3830 Set the width of the border to be drawn around the text using @var{bordercolor}.
3831 The default value of @var{borderw} is 0.
3834 Set the color to be used for drawing border around text. For the syntax of this
3835 option, check the "Color" section in the ffmpeg-utils manual.
3837 The default value of @var{bordercolor} is "black".
3840 Select how the @var{text} is expanded. Can be either @code{none},
3841 @code{strftime} (deprecated) or
3842 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3846 If true, check and fix text coords to avoid clipping.
3849 The color to be used for drawing fonts. For the syntax of this option, check
3850 the "Color" section in the ffmpeg-utils manual.
3852 The default value of @var{fontcolor} is "black".
3854 @item fontcolor_expr
3855 String which is expanded the same way as @var{text} to obtain dynamic
3856 @var{fontcolor} value. By default this option has empty value and is not
3857 processed. When this option is set, it overrides @var{fontcolor} option.
3860 The font family to be used for drawing text. By default Sans.
3863 The font file to be used for drawing text. The path must be included.
3864 This parameter is mandatory if the fontconfig support is disabled.
3867 The font size to be used for drawing text.
3868 The default value of @var{fontsize} is 16.
3871 If set to 1, attempt to shape the text (for example, reverse the order of
3872 right-to-left text and join Arabic characters) before drawing it.
3873 Otherwise, just draw the text exactly as given.
3874 By default 1 (if supported).
3877 The flags to be used for loading the fonts.
3879 The flags map the corresponding flags supported by libfreetype, and are
3880 a combination of the following values:
3887 @item vertical_layout
3888 @item force_autohint
3891 @item ignore_global_advance_width
3893 @item ignore_transform
3899 Default value is "default".
3901 For more information consult the documentation for the FT_LOAD_*
3905 The color to be used for drawing a shadow behind the drawn text. For the
3906 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3908 The default value of @var{shadowcolor} is "black".
3912 The x and y offsets for the text shadow position with respect to the
3913 position of the text. They can be either positive or negative
3914 values. The default value for both is "0".
3917 The starting frame number for the n/frame_num variable. The default value
3921 The size in number of spaces to use for rendering the tab.
3925 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3926 format. It can be used with or without text parameter. @var{timecode_rate}
3927 option must be specified.
3929 @item timecode_rate, rate, r
3930 Set the timecode frame rate (timecode only).
3933 The text string to be drawn. The text must be a sequence of UTF-8
3935 This parameter is mandatory if no file is specified with the parameter
3939 A text file containing text to be drawn. The text must be a sequence
3940 of UTF-8 encoded characters.
3942 This parameter is mandatory if no text string is specified with the
3943 parameter @var{text}.
3945 If both @var{text} and @var{textfile} are specified, an error is thrown.
3948 If set to 1, the @var{textfile} will be reloaded before each frame.
3949 Be sure to update it atomically, or it may be read partially, or even fail.
3953 The expressions which specify the offsets where text will be drawn
3954 within the video frame. They are relative to the top/left border of the
3957 The default value of @var{x} and @var{y} is "0".
3959 See below for the list of accepted constants and functions.
3962 The parameters for @var{x} and @var{y} are expressions containing the
3963 following constants and functions:
3967 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3971 horizontal and vertical chroma subsample values. For example for the
3972 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3975 the height of each text line
3983 @item max_glyph_a, ascent
3984 the maximum distance from the baseline to the highest/upper grid
3985 coordinate used to place a glyph outline point, for all the rendered
3987 It is a positive value, due to the grid's orientation with the Y axis
3990 @item max_glyph_d, descent
3991 the maximum distance from the baseline to the lowest grid coordinate
3992 used to place a glyph outline point, for all the rendered glyphs.
3993 This is a negative value, due to the grid's orientation, with the Y axis
3997 maximum glyph height, that is the maximum height for all the glyphs
3998 contained in the rendered text, it is equivalent to @var{ascent} -
4002 maximum glyph width, that is the maximum width for all the glyphs
4003 contained in the rendered text
4006 the number of input frame, starting from 0
4008 @item rand(min, max)
4009 return a random number included between @var{min} and @var{max}
4012 The input sample aspect ratio.
4015 timestamp expressed in seconds, NAN if the input timestamp is unknown
4018 the height of the rendered text
4021 the width of the rendered text
4025 the x and y offset coordinates where the text is drawn.
4027 These parameters allow the @var{x} and @var{y} expressions to refer
4028 each other, so you can for example specify @code{y=x/dar}.
4031 @anchor{drawtext_expansion}
4032 @subsection Text expansion
4034 If @option{expansion} is set to @code{strftime},
4035 the filter recognizes strftime() sequences in the provided text and
4036 expands them accordingly. Check the documentation of strftime(). This
4037 feature is deprecated.
4039 If @option{expansion} is set to @code{none}, the text is printed verbatim.
4041 If @option{expansion} is set to @code{normal} (which is the default),
4042 the following expansion mechanism is used.
4044 The backslash character '\', followed by any character, always expands to
4045 the second character.
4047 Sequence of the form @code{%@{...@}} are expanded. The text between the
4048 braces is a function name, possibly followed by arguments separated by ':'.
4049 If the arguments contain special characters or delimiters (':' or '@}'),
4050 they should be escaped.
4052 Note that they probably must also be escaped as the value for the
4053 @option{text} option in the filter argument string and as the filter
4054 argument in the filtergraph description, and possibly also for the shell,
4055 that makes up to four levels of escaping; using a text file avoids these
4058 The following functions are available:
4063 The expression evaluation result.
4065 It must take one argument specifying the expression to be evaluated,
4066 which accepts the same constants and functions as the @var{x} and
4067 @var{y} values. Note that not all constants should be used, for
4068 example the text size is not known when evaluating the expression, so
4069 the constants @var{text_w} and @var{text_h} will have an undefined
4072 @item expr_int_format, eif
4073 Evaluate the expression's value and output as formatted integer.
4075 The first argument is the expression to be evaluated, just as for the @var{expr} function.
4076 The second argument specifies the output format. Allowed values are 'x', 'X', 'd' and
4077 'u'. They are treated exactly as in the printf function.
4078 The third parameter is optional and sets the number of positions taken by the output.
4079 It can be used to add padding with zeros from the left.
4082 The time at which the filter is running, expressed in UTC.
4083 It can accept an argument: a strftime() format string.
4086 The time at which the filter is running, expressed in the local time zone.
4087 It can accept an argument: a strftime() format string.
4090 Frame metadata. It must take one argument specifying metadata key.
4093 The frame number, starting from 0.
4096 A 1 character description of the current picture type.
4099 The timestamp of the current frame.
4100 It can take up to two arguments.
4102 The first argument is the format of the timestamp; it defaults to @code{flt}
4103 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
4104 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
4106 The second argument is an offset added to the timestamp.
4110 @subsection Examples
4114 Draw "Test Text" with font FreeSerif, using the default values for the
4115 optional parameters.
4118 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
4122 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
4123 and y=50 (counting from the top-left corner of the screen), text is
4124 yellow with a red box around it. Both the text and the box have an
4128 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
4129 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
4132 Note that the double quotes are not necessary if spaces are not used
4133 within the parameter list.
4136 Show the text at the center of the video frame:
4138 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
4142 Show a text line sliding from right to left in the last row of the video
4143 frame. The file @file{LONG_LINE} is assumed to contain a single line
4146 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
4150 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
4152 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
4156 Draw a single green letter "g", at the center of the input video.
4157 The glyph baseline is placed at half screen height.
4159 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
4163 Show text for 1 second every 3 seconds:
4165 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
4169 Use fontconfig to set the font. Note that the colons need to be escaped.
4171 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
4175 Print the date of a real-time encoding (see strftime(3)):
4177 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
4181 Show text fading in and out (appearing/disappearing):
4184 DS=1.0 # display start
4185 DE=10.0 # display end
4186 FID=1.5 # fade in duration
4187 FOD=5 # fade out duration
4188 ffplay -f lavfi "color,drawtext=text=TEST:fontsize=50:fontfile=FreeSerif.ttf:fontcolor_expr=ff0000%@{eif\\\\: clip(255*(1*between(t\\, $DS + $FID\\, $DE - $FOD) + ((t - $DS)/$FID)*between(t\\, $DS\\, $DS + $FID) + (-(t - $DE)/$FOD)*between(t\\, $DE - $FOD\\, $DE) )\\, 0\\, 255) \\\\: x\\\\: 2 @}"
4193 For more information about libfreetype, check:
4194 @url{http://www.freetype.org/}.
4196 For more information about fontconfig, check:
4197 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
4199 For more information about libfribidi, check:
4200 @url{http://fribidi.org/}.
4204 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
4206 The filter accepts the following options:
4211 Set low and high threshold values used by the Canny thresholding
4214 The high threshold selects the "strong" edge pixels, which are then
4215 connected through 8-connectivity with the "weak" edge pixels selected
4216 by the low threshold.
4218 @var{low} and @var{high} threshold values must be chosen in the range
4219 [0,1], and @var{low} should be lesser or equal to @var{high}.
4221 Default value for @var{low} is @code{20/255}, and default value for @var{high}
4225 Define the drawing mode.
4229 Draw white/gray wires on black background.
4232 Mix the colors to create a paint/cartoon effect.
4235 Default value is @var{wires}.
4238 @subsection Examples
4242 Standard edge detection with custom values for the hysteresis thresholding:
4244 edgedetect=low=0.1:high=0.4
4248 Painting effect without thresholding:
4250 edgedetect=mode=colormix:high=0
4254 @section extractplanes
4256 Extract color channel components from input video stream into
4257 separate grayscale video streams.
4259 The filter accepts the following option:
4263 Set plane(s) to extract.
4265 Available values for planes are:
4276 Choosing planes not available in the input will result in an error.
4277 That means you cannot select @code{r}, @code{g}, @code{b} planes
4278 with @code{y}, @code{u}, @code{v} planes at same time.
4281 @subsection Examples
4285 Extract luma, u and v color channel component from input video frame
4286 into 3 grayscale outputs:
4288 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
4294 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4296 For each input image, the filter will compute the optimal mapping from
4297 the input to the output given the codebook length, that is the number
4298 of distinct output colors.
4300 This filter accepts the following options.
4303 @item codebook_length, l
4304 Set codebook length. The value must be a positive integer, and
4305 represents the number of distinct output colors. Default value is 256.
4308 Set the maximum number of iterations to apply for computing the optimal
4309 mapping. The higher the value the better the result and the higher the
4310 computation time. Default value is 1.
4313 Set a random seed, must be an integer included between 0 and
4314 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4315 will try to use a good random seed on a best effort basis.
4320 Apply a fade-in/out effect to the input video.
4322 It accepts the following parameters:
4326 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4328 Default is @code{in}.
4330 @item start_frame, s
4331 Specify the number of the frame to start applying the fade
4332 effect at. Default is 0.
4335 The number of frames that the fade effect lasts. At the end of the
4336 fade-in effect, the output video will have the same intensity as the input video.
4337 At the end of the fade-out transition, the output video will be filled with the
4338 selected @option{color}.
4342 If set to 1, fade only alpha channel, if one exists on the input.
4345 @item start_time, st
4346 Specify the timestamp (in seconds) of the frame to start to apply the fade
4347 effect. If both start_frame and start_time are specified, the fade will start at
4348 whichever comes last. Default is 0.
4351 The number of seconds for which the fade effect has to last. At the end of the
4352 fade-in effect the output video will have the same intensity as the input video,
4353 at the end of the fade-out transition the output video will be filled with the
4354 selected @option{color}.
4355 If both duration and nb_frames are specified, duration is used. Default is 0.
4358 Specify the color of the fade. Default is "black".
4361 @subsection Examples
4365 Fade in the first 30 frames of video:
4370 The command above is equivalent to:
4376 Fade out the last 45 frames of a 200-frame video:
4379 fade=type=out:start_frame=155:nb_frames=45
4383 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4385 fade=in:0:25, fade=out:975:25
4389 Make the first 5 frames yellow, then fade in from frame 5-24:
4391 fade=in:5:20:color=yellow
4395 Fade in alpha over first 25 frames of video:
4397 fade=in:0:25:alpha=1
4401 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4403 fade=t=in:st=5.5:d=0.5
4410 Extract a single field from an interlaced image using stride
4411 arithmetic to avoid wasting CPU time. The output frames are marked as
4414 The filter accepts the following options:
4418 Specify whether to extract the top (if the value is @code{0} or
4419 @code{top}) or the bottom field (if the value is @code{1} or
4425 Field matching filter for inverse telecine. It is meant to reconstruct the
4426 progressive frames from a telecined stream. The filter does not drop duplicated
4427 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4428 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4430 The separation of the field matching and the decimation is notably motivated by
4431 the possibility of inserting a de-interlacing filter fallback between the two.
4432 If the source has mixed telecined and real interlaced content,
4433 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4434 But these remaining combed frames will be marked as interlaced, and thus can be
4435 de-interlaced by a later filter such as @ref{yadif} before decimation.
4437 In addition to the various configuration options, @code{fieldmatch} can take an
4438 optional second stream, activated through the @option{ppsrc} option. If
4439 enabled, the frames reconstruction will be based on the fields and frames from
4440 this second stream. This allows the first input to be pre-processed in order to
4441 help the various algorithms of the filter, while keeping the output lossless
4442 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4443 or brightness/contrast adjustments can help.
4445 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4446 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4447 which @code{fieldmatch} is based on. While the semantic and usage are very
4448 close, some behaviour and options names can differ.
4450 The filter accepts the following options:
4454 Specify the assumed field order of the input stream. Available values are:
4458 Auto detect parity (use FFmpeg's internal parity value).
4460 Assume bottom field first.
4462 Assume top field first.
4465 Note that it is sometimes recommended not to trust the parity announced by the
4468 Default value is @var{auto}.
4471 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4472 sense that it won't risk creating jerkiness due to duplicate frames when
4473 possible, but if there are bad edits or blended fields it will end up
4474 outputting combed frames when a good match might actually exist. On the other
4475 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4476 but will almost always find a good frame if there is one. The other values are
4477 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4478 jerkiness and creating duplicate frames versus finding good matches in sections
4479 with bad edits, orphaned fields, blended fields, etc.
4481 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4483 Available values are:
4487 2-way matching (p/c)
4489 2-way matching, and trying 3rd match if still combed (p/c + n)
4491 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4493 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4494 still combed (p/c + n + u/b)
4496 3-way matching (p/c/n)
4498 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4499 detected as combed (p/c/n + u/b)
4502 The parenthesis at the end indicate the matches that would be used for that
4503 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4506 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4509 Default value is @var{pc_n}.
4512 Mark the main input stream as a pre-processed input, and enable the secondary
4513 input stream as the clean source to pick the fields from. See the filter
4514 introduction for more details. It is similar to the @option{clip2} feature from
4517 Default value is @code{0} (disabled).
4520 Set the field to match from. It is recommended to set this to the same value as
4521 @option{order} unless you experience matching failures with that setting. In
4522 certain circumstances changing the field that is used to match from can have a
4523 large impact on matching performance. Available values are:
4527 Automatic (same value as @option{order}).
4529 Match from the bottom field.
4531 Match from the top field.
4534 Default value is @var{auto}.
4537 Set whether or not chroma is included during the match comparisons. In most
4538 cases it is recommended to leave this enabled. You should set this to @code{0}
4539 only if your clip has bad chroma problems such as heavy rainbowing or other
4540 artifacts. Setting this to @code{0} could also be used to speed things up at
4541 the cost of some accuracy.
4543 Default value is @code{1}.
4547 These define an exclusion band which excludes the lines between @option{y0} and
4548 @option{y1} from being included in the field matching decision. An exclusion
4549 band can be used to ignore subtitles, a logo, or other things that may
4550 interfere with the matching. @option{y0} sets the starting scan line and
4551 @option{y1} sets the ending line; all lines in between @option{y0} and
4552 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4553 @option{y0} and @option{y1} to the same value will disable the feature.
4554 @option{y0} and @option{y1} defaults to @code{0}.
4557 Set the scene change detection threshold as a percentage of maximum change on
4558 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4559 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4560 @option{scthresh} is @code{[0.0, 100.0]}.
4562 Default value is @code{12.0}.
4565 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4566 account the combed scores of matches when deciding what match to use as the
4567 final match. Available values are:
4571 No final matching based on combed scores.
4573 Combed scores are only used when a scene change is detected.
4575 Use combed scores all the time.
4578 Default is @var{sc}.
4581 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4582 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4583 Available values are:
4587 No forced calculation.
4589 Force p/c/n calculations.
4591 Force p/c/n/u/b calculations.
4594 Default value is @var{none}.
4597 This is the area combing threshold used for combed frame detection. This
4598 essentially controls how "strong" or "visible" combing must be to be detected.
4599 Larger values mean combing must be more visible and smaller values mean combing
4600 can be less visible or strong and still be detected. Valid settings are from
4601 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4602 be detected as combed). This is basically a pixel difference value. A good
4603 range is @code{[8, 12]}.
4605 Default value is @code{9}.
4608 Sets whether or not chroma is considered in the combed frame decision. Only
4609 disable this if your source has chroma problems (rainbowing, etc.) that are
4610 causing problems for the combed frame detection with chroma enabled. Actually,
4611 using @option{chroma}=@var{0} is usually more reliable, except for the case
4612 where there is chroma only combing in the source.
4614 Default value is @code{0}.
4618 Respectively set the x-axis and y-axis size of the window used during combed
4619 frame detection. This has to do with the size of the area in which
4620 @option{combpel} pixels are required to be detected as combed for a frame to be
4621 declared combed. See the @option{combpel} parameter description for more info.
4622 Possible values are any number that is a power of 2 starting at 4 and going up
4625 Default value is @code{16}.
4628 The number of combed pixels inside any of the @option{blocky} by
4629 @option{blockx} size blocks on the frame for the frame to be detected as
4630 combed. While @option{cthresh} controls how "visible" the combing must be, this
4631 setting controls "how much" combing there must be in any localized area (a
4632 window defined by the @option{blockx} and @option{blocky} settings) on the
4633 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4634 which point no frames will ever be detected as combed). This setting is known
4635 as @option{MI} in TFM/VFM vocabulary.
4637 Default value is @code{80}.
4640 @anchor{p/c/n/u/b meaning}
4641 @subsection p/c/n/u/b meaning
4643 @subsubsection p/c/n
4645 We assume the following telecined stream:
4648 Top fields: 1 2 2 3 4
4649 Bottom fields: 1 2 3 4 4
4652 The numbers correspond to the progressive frame the fields relate to. Here, the
4653 first two frames are progressive, the 3rd and 4th are combed, and so on.
4655 When @code{fieldmatch} is configured to run a matching from bottom
4656 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4661 B 1 2 3 4 4 <-- matching reference
4670 As a result of the field matching, we can see that some frames get duplicated.
4671 To perform a complete inverse telecine, you need to rely on a decimation filter
4672 after this operation. See for instance the @ref{decimate} filter.
4674 The same operation now matching from top fields (@option{field}=@var{top})
4679 T 1 2 2 3 4 <-- matching reference
4689 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4690 basically, they refer to the frame and field of the opposite parity:
4693 @item @var{p} matches the field of the opposite parity in the previous frame
4694 @item @var{c} matches the field of the opposite parity in the current frame
4695 @item @var{n} matches the field of the opposite parity in the next frame
4700 The @var{u} and @var{b} matching are a bit special in the sense that they match
4701 from the opposite parity flag. In the following examples, we assume that we are
4702 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4703 'x' is placed above and below each matched fields.
4705 With bottom matching (@option{field}=@var{bottom}):
4710 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4711 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4719 With top matching (@option{field}=@var{top}):
4724 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4725 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4733 @subsection Examples
4735 Simple IVTC of a top field first telecined stream:
4737 fieldmatch=order=tff:combmatch=none, decimate
4740 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4742 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4747 Transform the field order of the input video.
4749 It accepts the following parameters:
4754 The output field order. Valid values are @var{tff} for top field first or @var{bff}
4755 for bottom field first.
4758 The default value is @samp{tff}.
4760 The transformation is done by shifting the picture content up or down
4761 by one line, and filling the remaining line with appropriate picture content.
4762 This method is consistent with most broadcast field order converters.
4764 If the input video is not flagged as being interlaced, or it is already
4765 flagged as being of the required output field order, then this filter does
4766 not alter the incoming video.
4768 It is very useful when converting to or from PAL DV material,
4769 which is bottom field first.
4773 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4778 Buffer input images and send them when they are requested.
4780 It is mainly useful when auto-inserted by the libavfilter
4783 It does not take parameters.
4788 Convert the input video to one of the specified pixel formats.
4789 Libavfilter will try to pick one that is suitable as input to
4792 It accepts the following parameters:
4796 A '|'-separated list of pixel format names, such as
4797 "pix_fmts=yuv420p|monow|rgb24".
4801 @subsection Examples
4805 Convert the input video to the @var{yuv420p} format
4807 format=pix_fmts=yuv420p
4810 Convert the input video to any of the formats in the list
4812 format=pix_fmts=yuv420p|yuv444p|yuv410p
4819 Convert the video to specified constant frame rate by duplicating or dropping
4820 frames as necessary.
4822 It accepts the following parameters:
4826 The desired output frame rate. The default is @code{25}.
4831 Possible values are:
4834 zero round towards 0
4838 round towards -infinity
4840 round towards +infinity
4844 The default is @code{near}.
4847 Assume the first PTS should be the given value, in seconds. This allows for
4848 padding/trimming at the start of stream. By default, no assumption is made
4849 about the first frame's expected PTS, so no padding or trimming is done.
4850 For example, this could be set to 0 to pad the beginning with duplicates of
4851 the first frame if a video stream starts after the audio stream or to trim any
4852 frames with a negative PTS.
4856 Alternatively, the options can be specified as a flat string:
4857 @var{fps}[:@var{round}].
4859 See also the @ref{setpts} filter.
4861 @subsection Examples
4865 A typical usage in order to set the fps to 25:
4871 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4873 fps=fps=film:round=near
4879 Pack two different video streams into a stereoscopic video, setting proper
4880 metadata on supported codecs. The two views should have the same size and
4881 framerate and processing will stop when the shorter video ends. Please note
4882 that you may conveniently adjust view properties with the @ref{scale} and
4885 It accepts the following parameters:
4889 The desired packing format. Supported values are:
4894 The views are next to each other (default).
4897 The views are on top of each other.
4900 The views are packed by line.
4903 The views are packed by column.
4906 The views are temporally interleaved.
4915 # Convert left and right views into a frame-sequential video
4916 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
4918 # Convert views into a side-by-side video with the same output resolution as the input
4919 ffmpeg -i LEFT -i RIGHT -filter_complex [0:v]scale=w=iw/2[left],[1:v]scale=w=iw/2[right],[left][right]framepack=sbs OUTPUT
4924 Select one frame every N-th frame.
4926 This filter accepts the following option:
4929 Select frame after every @code{step} frames.
4930 Allowed values are positive integers higher than 0. Default value is @code{1}.
4936 Apply a frei0r effect to the input video.
4938 To enable the compilation of this filter, you need to install the frei0r
4939 header and configure FFmpeg with @code{--enable-frei0r}.
4941 It accepts the following parameters:
4946 The name of the frei0r effect to load. If the environment variable
4947 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
4948 directories specified by the colon-separated list in @env{FREIOR_PATH}.
4949 Otherwise, the standard frei0r paths are searched, in this order:
4950 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
4951 @file{/usr/lib/frei0r-1/}.
4954 A '|'-separated list of parameters to pass to the frei0r effect.
4958 A frei0r effect parameter can be a boolean (its value is either
4959 "y" or "n"), a double, a color (specified as
4960 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
4961 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
4962 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
4963 @var{X} and @var{Y} are floating point numbers) and/or a string.
4965 The number and types of parameters depend on the loaded effect. If an
4966 effect parameter is not specified, the default value is set.
4968 @subsection Examples
4972 Apply the distort0r effect, setting the first two double parameters:
4974 frei0r=filter_name=distort0r:filter_params=0.5|0.01
4978 Apply the colordistance effect, taking a color as the first parameter:
4980 frei0r=colordistance:0.2/0.3/0.4
4981 frei0r=colordistance:violet
4982 frei0r=colordistance:0x112233
4986 Apply the perspective effect, specifying the top left and top right image
4989 frei0r=perspective:0.2/0.2|0.8/0.2
4993 For more information, see
4994 @url{http://frei0r.dyne.org}
4998 The filter accepts the following options:
5002 Set the luminance expression.
5004 Set the chrominance blue expression.
5006 Set the chrominance red expression.
5008 Set the alpha expression.
5010 Set the red expression.
5012 Set the green expression.
5014 Set the blue expression.
5017 The colorspace is selected according to the specified options. If one
5018 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
5019 options is specified, the filter will automatically select a YCbCr
5020 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
5021 @option{blue_expr} options is specified, it will select an RGB
5024 If one of the chrominance expression is not defined, it falls back on the other
5025 one. If no alpha expression is specified it will evaluate to opaque value.
5026 If none of chrominance expressions are specified, they will evaluate
5027 to the luminance expression.
5029 The expressions can use the following variables and functions:
5033 The sequential number of the filtered frame, starting from @code{0}.
5037 The coordinates of the current sample.
5041 The width and height of the image.
5045 Width and height scale depending on the currently filtered plane. It is the
5046 ratio between the corresponding luma plane number of pixels and the current
5047 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
5048 @code{0.5,0.5} for chroma planes.
5051 Time of the current frame, expressed in seconds.
5054 Return the value of the pixel at location (@var{x},@var{y}) of the current
5058 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
5062 Return the value of the pixel at location (@var{x},@var{y}) of the
5063 blue-difference chroma plane. Return 0 if there is no such plane.
5066 Return the value of the pixel at location (@var{x},@var{y}) of the
5067 red-difference chroma plane. Return 0 if there is no such plane.
5072 Return the value of the pixel at location (@var{x},@var{y}) of the
5073 red/green/blue component. Return 0 if there is no such component.
5076 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
5077 plane. Return 0 if there is no such plane.
5080 For functions, if @var{x} and @var{y} are outside the area, the value will be
5081 automatically clipped to the closer edge.
5083 @subsection Examples
5087 Flip the image horizontally:
5093 Generate a bidimensional sine wave, with angle @code{PI/3} and a
5094 wavelength of 100 pixels:
5096 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
5100 Generate a fancy enigmatic moving light:
5102 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
5106 Generate a quick emboss effect:
5108 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
5112 Modify RGB components depending on pixel position:
5114 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
5118 Create a radial gradient that is the same size as the input (also see
5119 the @ref{vignette} filter):
5121 geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
5125 Create a linear gradient to use as a mask for another filter, then
5126 compose with @ref{overlay}. In this example the video will gradually
5127 become more blurry from the top to the bottom of the y-axis as defined
5128 by the linear gradient:
5130 ffmpeg -i input.mp4 -filter_complex "geq=lum=255*(Y/H),format=gray[grad];[0:v]boxblur=4[blur];[blur][grad]alphamerge[alpha];[0:v][alpha]overlay" output.mp4
5136 Fix the banding artifacts that are sometimes introduced into nearly flat
5137 regions by truncation to 8bit color depth.
5138 Interpolate the gradients that should go where the bands are, and
5141 It is designed for playback only. Do not use it prior to
5142 lossy compression, because compression tends to lose the dither and
5143 bring back the bands.
5145 It accepts the following parameters:
5150 The maximum amount by which the filter will change any one pixel. This is also
5151 the threshold for detecting nearly flat regions. Acceptable values range from
5152 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
5156 The neighborhood to fit the gradient to. A larger radius makes for smoother
5157 gradients, but also prevents the filter from modifying the pixels near detailed
5158 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
5159 values will be clipped to the valid range.
5163 Alternatively, the options can be specified as a flat string:
5164 @var{strength}[:@var{radius}]
5166 @subsection Examples
5170 Apply the filter with a @code{3.5} strength and radius of @code{8}:
5176 Specify radius, omitting the strength (which will fall-back to the default
5187 Apply a Hald CLUT to a video stream.
5189 First input is the video stream to process, and second one is the Hald CLUT.
5190 The Hald CLUT input can be a simple picture or a complete video stream.
5192 The filter accepts the following options:
5196 Force termination when the shortest input terminates. Default is @code{0}.
5198 Continue applying the last CLUT after the end of the stream. A value of
5199 @code{0} disable the filter after the last frame of the CLUT is reached.
5200 Default is @code{1}.
5203 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
5204 filters share the same internals).
5206 More information about the Hald CLUT can be found on Eskil Steenberg's website
5207 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
5209 @subsection Workflow examples
5211 @subsubsection Hald CLUT video stream
5213 Generate an identity Hald CLUT stream altered with various effects:
5215 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
5218 Note: make sure you use a lossless codec.
5220 Then use it with @code{haldclut} to apply it on some random stream:
5222 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
5225 The Hald CLUT will be applied to the 10 first seconds (duration of
5226 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
5227 to the remaining frames of the @code{mandelbrot} stream.
5229 @subsubsection Hald CLUT with preview
5231 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
5232 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
5233 biggest possible square starting at the top left of the picture. The remaining
5234 padding pixels (bottom or right) will be ignored. This area can be used to add
5235 a preview of the Hald CLUT.
5237 Typically, the following generated Hald CLUT will be supported by the
5238 @code{haldclut} filter:
5241 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
5242 pad=iw+320 [padded_clut];
5243 smptebars=s=320x256, split [a][b];
5244 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
5245 [main][b] overlay=W-320" -frames:v 1 clut.png
5248 It contains the original and a preview of the effect of the CLUT: SMPTE color
5249 bars are displayed on the right-top, and below the same color bars processed by
5252 Then, the effect of this Hald CLUT can be visualized with:
5254 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
5259 Flip the input video horizontally.
5261 For example, to horizontally flip the input video with @command{ffmpeg}:
5263 ffmpeg -i in.avi -vf "hflip" out.avi
5267 This filter applies a global color histogram equalization on a
5270 It can be used to correct video that has a compressed range of pixel
5271 intensities. The filter redistributes the pixel intensities to
5272 equalize their distribution across the intensity range. It may be
5273 viewed as an "automatically adjusting contrast filter". This filter is
5274 useful only for correcting degraded or poorly captured source
5277 The filter accepts the following options:
5281 Determine the amount of equalization to be applied. As the strength
5282 is reduced, the distribution of pixel intensities more-and-more
5283 approaches that of the input frame. The value must be a float number
5284 in the range [0,1] and defaults to 0.200.
5287 Set the maximum intensity that can generated and scale the output
5288 values appropriately. The strength should be set as desired and then
5289 the intensity can be limited if needed to avoid washing-out. The value
5290 must be a float number in the range [0,1] and defaults to 0.210.
5293 Set the antibanding level. If enabled the filter will randomly vary
5294 the luminance of output pixels by a small amount to avoid banding of
5295 the histogram. Possible values are @code{none}, @code{weak} or
5296 @code{strong}. It defaults to @code{none}.
5301 Compute and draw a color distribution histogram for the input video.
5303 The computed histogram is a representation of the color component
5304 distribution in an image.
5306 The filter accepts the following options:
5312 It accepts the following values:
5315 Standard histogram that displays the color components distribution in an
5316 image. Displays color graph for each color component. Shows distribution of
5317 the Y, U, V, A or R, G, B components, depending on input format, in the
5318 current frame. Below each graph a color component scale meter is shown.
5321 Displays chroma values (U/V color placement) in a two dimensional
5322 graph (which is called a vectorscope). The brighter a pixel in the
5323 vectorscope, the more pixels of the input frame correspond to that pixel
5324 (i.e., more pixels have this chroma value). The V component is displayed on
5325 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5326 side being V = 255. The U component is displayed on the vertical (Y) axis,
5327 with the top representing U = 0 and the bottom representing U = 255.
5329 The position of a white pixel in the graph corresponds to the chroma value of
5330 a pixel of the input clip. The graph can therefore be used to read the hue
5331 (color flavor) and the saturation (the dominance of the hue in the color). As
5332 the hue of a color changes, it moves around the square. At the center of the
5333 square the saturation is zero, which means that the corresponding pixel has no
5334 color. If the amount of a specific color is increased (while leaving the other
5335 colors unchanged) the saturation increases, and the indicator moves towards
5336 the edge of the square.
5339 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5343 Per row/column color component graph. In row mode, the graph on the left side
5344 represents color component value 0 and the right side represents value = 255.
5345 In column mode, the top side represents color component value = 0 and bottom
5346 side represents value = 255.
5348 Default value is @code{levels}.
5351 Set height of level in @code{levels}. Default value is @code{200}.
5352 Allowed range is [50, 2048].
5355 Set height of color scale in @code{levels}. Default value is @code{12}.
5356 Allowed range is [0, 40].
5359 Set step for @code{waveform} mode. Smaller values are useful to find out how
5360 many values of the same luminance are distributed across input rows/columns.
5361 Default value is @code{10}. Allowed range is [1, 255].
5364 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5365 Default is @code{row}.
5367 @item waveform_mirror
5368 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5369 means mirrored. In mirrored mode, higher values will be represented on the left
5370 side for @code{row} mode and at the top for @code{column} mode. Default is
5371 @code{0} (unmirrored).
5374 Set display mode for @code{waveform} and @code{levels}.
5375 It accepts the following values:
5378 Display separate graph for the color components side by side in
5379 @code{row} waveform mode or one below the other in @code{column} waveform mode
5380 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5381 per color component graphs are placed below each other.
5383 Using this display mode in @code{waveform} histogram mode makes it easy to
5384 spot color casts in the highlights and shadows of an image, by comparing the
5385 contours of the top and the bottom graphs of each waveform. Since whites,
5386 grays, and blacks are characterized by exactly equal amounts of red, green,
5387 and blue, neutral areas of the picture should display three waveforms of
5388 roughly equal width/height. If not, the correction is easy to perform by
5389 making level adjustments the three waveforms.
5392 Presents information identical to that in the @code{parade}, except
5393 that the graphs representing color components are superimposed directly
5396 This display mode in @code{waveform} histogram mode makes it easier to spot
5397 relative differences or similarities in overlapping areas of the color
5398 components that are supposed to be identical, such as neutral whites, grays,
5401 Default is @code{parade}.
5404 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5405 Default is @code{linear}.
5408 @subsection Examples
5413 Calculate and draw histogram:
5415 ffplay -i input -vf histogram
5423 This is a high precision/quality 3d denoise filter. It aims to reduce
5424 image noise, producing smooth images and making still images really
5425 still. It should enhance compressibility.
5427 It accepts the following optional parameters:
5431 A non-negative floating point number which specifies spatial luma strength.
5434 @item chroma_spatial
5435 A non-negative floating point number which specifies spatial chroma strength.
5436 It defaults to 3.0*@var{luma_spatial}/4.0.
5439 A floating point number which specifies luma temporal strength. It defaults to
5440 6.0*@var{luma_spatial}/4.0.
5443 A floating point number which specifies chroma temporal strength. It defaults to
5444 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5449 Apply a high-quality magnification filter designed for pixel art. This filter
5450 was originally created by Maxim Stepin.
5452 It accepts the following option:
5456 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
5457 @code{hq3x} and @code{4} for @code{hq4x}.
5458 Default is @code{3}.
5463 Modify the hue and/or the saturation of the input.
5465 It accepts the following parameters:
5469 Specify the hue angle as a number of degrees. It accepts an expression,
5470 and defaults to "0".
5473 Specify the saturation in the [-10,10] range. It accepts an expression and
5477 Specify the hue angle as a number of radians. It accepts an
5478 expression, and defaults to "0".
5481 Specify the brightness in the [-10,10] range. It accepts an expression and
5485 @option{h} and @option{H} are mutually exclusive, and can't be
5486 specified at the same time.
5488 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5489 expressions containing the following constants:
5493 frame count of the input frame starting from 0
5496 presentation timestamp of the input frame expressed in time base units
5499 frame rate of the input video, NAN if the input frame rate is unknown
5502 timestamp expressed in seconds, NAN if the input timestamp is unknown
5505 time base of the input video
5508 @subsection Examples
5512 Set the hue to 90 degrees and the saturation to 1.0:
5518 Same command but expressing the hue in radians:
5524 Rotate hue and make the saturation swing between 0
5525 and 2 over a period of 1 second:
5527 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5531 Apply a 3 seconds saturation fade-in effect starting at 0:
5536 The general fade-in expression can be written as:
5538 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5542 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5544 hue="s=max(0\, min(1\, (8-t)/3))"
5547 The general fade-out expression can be written as:
5549 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5554 @subsection Commands
5556 This filter supports the following commands:
5562 Modify the hue and/or the saturation and/or brightness of the input video.
5563 The command accepts the same syntax of the corresponding option.
5565 If the specified expression is not valid, it is kept at its current
5571 Detect video interlacing type.
5573 This filter tries to detect if the input is interlaced or progressive,
5574 top or bottom field first.
5576 The filter accepts the following options:
5580 Set interlacing threshold.
5582 Set progressive threshold.
5587 Deinterleave or interleave fields.
5589 This filter allows one to process interlaced images fields without
5590 deinterlacing them. Deinterleaving splits the input frame into 2
5591 fields (so called half pictures). Odd lines are moved to the top
5592 half of the output image, even lines to the bottom half.
5593 You can process (filter) them independently and then re-interleave them.
5595 The filter accepts the following options:
5599 @item chroma_mode, c
5601 Available values for @var{luma_mode}, @var{chroma_mode} and
5602 @var{alpha_mode} are:
5608 @item deinterleave, d
5609 Deinterleave fields, placing one above the other.
5612 Interleave fields. Reverse the effect of deinterleaving.
5614 Default value is @code{none}.
5617 @item chroma_swap, cs
5618 @item alpha_swap, as
5619 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5624 Simple interlacing filter from progressive contents. This interleaves upper (or
5625 lower) lines from odd frames with lower (or upper) lines from even frames,
5626 halving the frame rate and preserving image height.
5629 Original Original New Frame
5630 Frame 'j' Frame 'j+1' (tff)
5631 ========== =========== ==================
5632 Line 0 --------------------> Frame 'j' Line 0
5633 Line 1 Line 1 ----> Frame 'j+1' Line 1
5634 Line 2 ---------------------> Frame 'j' Line 2
5635 Line 3 Line 3 ----> Frame 'j+1' Line 3
5637 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5640 It accepts the following optional parameters:
5644 This determines whether the interlaced frame is taken from the even
5645 (tff - default) or odd (bff) lines of the progressive frame.
5648 Enable (default) or disable the vertical lowpass filter to avoid twitter
5649 interlacing and reduce moire patterns.
5654 Deinterlace input video by applying Donald Graft's adaptive kernel
5655 deinterling. Work on interlaced parts of a video to produce
5658 The description of the accepted parameters follows.
5662 Set the threshold which affects the filter's tolerance when
5663 determining if a pixel line must be processed. It must be an integer
5664 in the range [0,255] and defaults to 10. A value of 0 will result in
5665 applying the process on every pixels.
5668 Paint pixels exceeding the threshold value to white if set to 1.
5672 Set the fields order. Swap fields if set to 1, leave fields alone if
5676 Enable additional sharpening if set to 1. Default is 0.
5679 Enable twoway sharpening if set to 1. Default is 0.
5682 @subsection Examples
5686 Apply default values:
5688 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5692 Enable additional sharpening:
5698 Paint processed pixels in white:
5704 @section lenscorrection
5706 Correct radial lens distortion
5708 This filter can be used to correct for radial distortion as can result from the use
5709 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
5710 one can use tools available for example as part of opencv or simply trial-and-error.
5711 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
5712 and extract the k1 and k2 coefficients from the resulting matrix.
5714 Note that effectively the same filter is available in the open-source tools Krita and
5715 Digikam from the KDE project.
5717 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
5718 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
5719 brightness distribution, so you may want to use both filters together in certain
5720 cases, though you will have to take care of ordering, i.e. whether vignetting should
5721 be applied before or after lens correction.
5725 The filter accepts the following options:
5729 Relative x-coordinate of the focal point of the image, and thereby the center of the
5730 distrortion. This value has a range [0,1] and is expressed as fractions of the image
5733 Relative y-coordinate of the focal point of the image, and thereby the center of the
5734 distrortion. This value has a range [0,1] and is expressed as fractions of the image
5737 Coefficient of the quadratic correction term. 0.5 means no correction.
5739 Coefficient of the double quadratic correction term. 0.5 means no correction.
5742 The formula that generates the correction is:
5744 @var{r_src} = @var{r_tgt} * (1 + @var{k1} * (@var{r_tgt} / @var{r_0})^2 + @var{k2} * (@var{r_tgt} / @var{r_0})^4)
5746 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
5747 distances from the focal point in the source and target images, respectively.
5752 Apply a 3D LUT to an input video.
5754 The filter accepts the following options:
5758 Set the 3D LUT file name.
5760 Currently supported formats:
5772 Select interpolation mode.
5774 Available values are:
5778 Use values from the nearest defined point.
5780 Interpolate values using the 8 points defining a cube.
5782 Interpolate values using a tetrahedron.
5786 @section lut, lutrgb, lutyuv
5788 Compute a look-up table for binding each pixel component input value
5789 to an output value, and apply it to the input video.
5791 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5792 to an RGB input video.
5794 These filters accept the following parameters:
5797 set first pixel component expression
5799 set second pixel component expression
5801 set third pixel component expression
5803 set fourth pixel component expression, corresponds to the alpha component
5806 set red component expression
5808 set green component expression
5810 set blue component expression
5812 alpha component expression
5815 set Y/luminance component expression
5817 set U/Cb component expression
5819 set V/Cr component expression
5822 Each of them specifies the expression to use for computing the lookup table for
5823 the corresponding pixel component values.
5825 The exact component associated to each of the @var{c*} options depends on the
5828 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5829 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5831 The expressions can contain the following constants and functions:
5836 The input width and height.
5839 The input value for the pixel component.
5842 The input value, clipped to the @var{minval}-@var{maxval} range.
5845 The maximum value for the pixel component.
5848 The minimum value for the pixel component.
5851 The negated value for the pixel component value, clipped to the
5852 @var{minval}-@var{maxval} range; it corresponds to the expression
5853 "maxval-clipval+minval".
5856 The computed value in @var{val}, clipped to the
5857 @var{minval}-@var{maxval} range.
5859 @item gammaval(gamma)
5860 The computed gamma correction value of the pixel component value,
5861 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
5863 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
5867 All expressions default to "val".
5869 @subsection Examples
5875 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
5876 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
5879 The above is the same as:
5881 lutrgb="r=negval:g=negval:b=negval"
5882 lutyuv="y=negval:u=negval:v=negval"
5892 Remove chroma components, turning the video into a graytone image:
5894 lutyuv="u=128:v=128"
5898 Apply a luma burning effect:
5904 Remove green and blue components:
5910 Set a constant alpha channel value on input:
5912 format=rgba,lutrgb=a="maxval-minval/2"
5916 Correct luminance gamma by a factor of 0.5:
5918 lutyuv=y=gammaval(0.5)
5922 Discard least significant bits of luma:
5924 lutyuv=y='bitand(val, 128+64+32)'
5928 @section mergeplanes
5930 Merge color channel components from several video streams.
5932 The filter accepts up to 4 input streams, and merge selected input
5933 planes to the output video.
5935 This filter accepts the following options:
5938 Set input to output plane mapping. Default is @code{0}.
5940 The mappings is specified as a bitmap. It should be specified as a
5941 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
5942 mapping for the first plane of the output stream. 'A' sets the number of
5943 the input stream to use (from 0 to 3), and 'a' the plane number of the
5944 corresponding input to use (from 0 to 3). The rest of the mappings is
5945 similar, 'Bb' describes the mapping for the output stream second
5946 plane, 'Cc' describes the mapping for the output stream third plane and
5947 'Dd' describes the mapping for the output stream fourth plane.
5950 Set output pixel format. Default is @code{yuva444p}.
5953 @subsection Examples
5957 Merge three gray video streams of same width and height into single video stream:
5959 [a0][a1][a2]mergeplanes=0x001020:yuv444p
5963 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
5965 [a0][a1]mergeplanes=0x00010210:yuva444p
5969 Swap Y and A plane in yuva444p stream:
5971 format=yuva444p,mergeplanes=0x03010200:yuva444p
5975 Swap U and V plane in yuv420p stream:
5977 format=yuv420p,mergeplanes=0x000201:yuv420p
5981 Cast a rgb24 clip to yuv444p:
5983 format=rgb24,mergeplanes=0x000102:yuv444p
5989 Apply motion-compensation deinterlacing.
5991 It needs one field per frame as input and must thus be used together
5992 with yadif=1/3 or equivalent.
5994 This filter accepts the following options:
5997 Set the deinterlacing mode.
5999 It accepts one of the following values:
6004 use iterative motion estimation
6006 like @samp{slow}, but use multiple reference frames.
6008 Default value is @samp{fast}.
6011 Set the picture field parity assumed for the input video. It must be
6012 one of the following values:
6016 assume top field first
6018 assume bottom field first
6021 Default value is @samp{bff}.
6024 Set per-block quantization parameter (QP) used by the internal
6027 Higher values should result in a smoother motion vector field but less
6028 optimal individual vectors. Default value is 1.
6033 Apply an MPlayer filter to the input video.
6035 This filter provides a wrapper around some of the filters of
6038 This wrapper is considered experimental. Some of the wrapped filters
6039 may not work properly and we may drop support for them, as they will
6040 be implemented natively into FFmpeg. Thus you should avoid
6041 depending on them when writing portable scripts.
6043 The filter accepts the parameters:
6044 @var{filter_name}[:=]@var{filter_params}
6046 @var{filter_name} is the name of a supported MPlayer filter,
6047 @var{filter_params} is a string containing the parameters accepted by
6050 The list of the currently supported filters follows:
6061 The parameter syntax and behavior for the listed filters are the same
6062 of the corresponding MPlayer filters. For detailed instructions check
6063 the "VIDEO FILTERS" section in the MPlayer manual.
6065 @subsection Examples
6069 Adjust gamma, brightness, contrast:
6075 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
6079 Drop frames that do not differ greatly from the previous frame in
6080 order to reduce frame rate.
6082 The main use of this filter is for very-low-bitrate encoding
6083 (e.g. streaming over dialup modem), but it could in theory be used for
6084 fixing movies that were inverse-telecined incorrectly.
6086 A description of the accepted options follows.
6090 Set the maximum number of consecutive frames which can be dropped (if
6091 positive), or the minimum interval between dropped frames (if
6092 negative). If the value is 0, the frame is dropped unregarding the
6093 number of previous sequentially dropped frames.
6100 Set the dropping threshold values.
6102 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
6103 represent actual pixel value differences, so a threshold of 64
6104 corresponds to 1 unit of difference for each pixel, or the same spread
6105 out differently over the block.
6107 A frame is a candidate for dropping if no 8x8 blocks differ by more
6108 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
6109 meaning the whole image) differ by more than a threshold of @option{lo}.
6111 Default value for @option{hi} is 64*12, default value for @option{lo} is
6112 64*5, and default value for @option{frac} is 0.33.
6120 It accepts an integer in input; if non-zero it negates the
6121 alpha component (if available). The default value in input is 0.
6125 Force libavfilter not to use any of the specified pixel formats for the
6126 input to the next filter.
6128 It accepts the following parameters:
6132 A '|'-separated list of pixel format names, such as
6133 apix_fmts=yuv420p|monow|rgb24".
6137 @subsection Examples
6141 Force libavfilter to use a format different from @var{yuv420p} for the
6142 input to the vflip filter:
6144 noformat=pix_fmts=yuv420p,vflip
6148 Convert the input video to any of the formats not contained in the list:
6150 noformat=yuv420p|yuv444p|yuv410p
6156 Add noise on video input frame.
6158 The filter accepts the following options:
6166 Set noise seed for specific pixel component or all pixel components in case
6167 of @var{all_seed}. Default value is @code{123457}.
6169 @item all_strength, alls
6170 @item c0_strength, c0s
6171 @item c1_strength, c1s
6172 @item c2_strength, c2s
6173 @item c3_strength, c3s
6174 Set noise strength for specific pixel component or all pixel components in case
6175 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
6177 @item all_flags, allf
6182 Set pixel component flags or set flags for all components if @var{all_flags}.
6183 Available values for component flags are:
6186 averaged temporal noise (smoother)
6188 mix random noise with a (semi)regular pattern
6190 temporal noise (noise pattern changes between frames)
6192 uniform noise (gaussian otherwise)
6196 @subsection Examples
6198 Add temporal and uniform noise to input video:
6200 noise=alls=20:allf=t+u
6205 Pass the video source unchanged to the output.
6209 Apply a video transform using libopencv.
6211 To enable this filter, install the libopencv library and headers and
6212 configure FFmpeg with @code{--enable-libopencv}.
6214 It accepts the following parameters:
6219 The name of the libopencv filter to apply.
6222 The parameters to pass to the libopencv filter. If not specified, the default
6227 Refer to the official libopencv documentation for more precise
6229 @url{http://docs.opencv.org/master/modules/imgproc/doc/filtering.html}
6231 Several libopencv filters are supported; see the following subsections.
6236 Dilate an image by using a specific structuring element.
6237 It corresponds to the libopencv function @code{cvDilate}.
6239 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
6241 @var{struct_el} represents a structuring element, and has the syntax:
6242 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
6244 @var{cols} and @var{rows} represent the number of columns and rows of
6245 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
6246 point, and @var{shape} the shape for the structuring element. @var{shape}
6247 must be "rect", "cross", "ellipse", or "custom".
6249 If the value for @var{shape} is "custom", it must be followed by a
6250 string of the form "=@var{filename}". The file with name
6251 @var{filename} is assumed to represent a binary image, with each
6252 printable character corresponding to a bright pixel. When a custom
6253 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
6254 or columns and rows of the read file are assumed instead.
6256 The default value for @var{struct_el} is "3x3+0x0/rect".
6258 @var{nb_iterations} specifies the number of times the transform is
6259 applied to the image, and defaults to 1.
6263 # Use the default values
6266 # Dilate using a structuring element with a 5x5 cross, iterating two times
6267 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
6269 # Read the shape from the file diamond.shape, iterating two times.
6270 # The file diamond.shape may contain a pattern of characters like this
6276 # The specified columns and rows are ignored
6277 # but the anchor point coordinates are not
6278 ocv=dilate:0x0+2x2/custom=diamond.shape|2
6283 Erode an image by using a specific structuring element.
6284 It corresponds to the libopencv function @code{cvErode}.
6286 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
6287 with the same syntax and semantics as the @ref{dilate} filter.
6291 Smooth the input video.
6293 The filter takes the following parameters:
6294 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
6296 @var{type} is the type of smooth filter to apply, and must be one of
6297 the following values: "blur", "blur_no_scale", "median", "gaussian",
6298 or "bilateral". The default value is "gaussian".
6300 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
6301 depend on the smooth type. @var{param1} and
6302 @var{param2} accept integer positive values or 0. @var{param3} and
6303 @var{param4} accept floating point values.
6305 The default value for @var{param1} is 3. The default value for the
6306 other parameters is 0.
6308 These parameters correspond to the parameters assigned to the
6309 libopencv function @code{cvSmooth}.
6314 Overlay one video on top of another.
6316 It takes two inputs and has one output. The first input is the "main"
6317 video on which the second input is overlayed.
6319 It accepts the following parameters:
6321 A description of the accepted options follows.
6326 Set the expression for the x and y coordinates of the overlayed video
6327 on the main video. Default value is "0" for both expressions. In case
6328 the expression is invalid, it is set to a huge value (meaning that the
6329 overlay will not be displayed within the output visible area).
6332 The action to take when EOF is encountered on the secondary input; it accepts
6333 one of the following values:
6337 Repeat the last frame (the default).
6341 Pass the main input through.
6345 Set when the expressions for @option{x}, and @option{y} are evaluated.
6347 It accepts the following values:
6350 only evaluate expressions once during the filter initialization or
6351 when a command is processed
6354 evaluate expressions for each incoming frame
6357 Default value is @samp{frame}.
6360 If set to 1, force the output to terminate when the shortest input
6361 terminates. Default value is 0.
6364 Set the format for the output video.
6366 It accepts the following values:
6381 Default value is @samp{yuv420}.
6383 @item rgb @emph{(deprecated)}
6384 If set to 1, force the filter to accept inputs in the RGB
6385 color space. Default value is 0. This option is deprecated, use
6386 @option{format} instead.
6389 If set to 1, force the filter to draw the last overlay frame over the
6390 main input until the end of the stream. A value of 0 disables this
6391 behavior. Default value is 1.
6394 The @option{x}, and @option{y} expressions can contain the following
6400 The main input width and height.
6404 The overlay input width and height.
6408 The computed values for @var{x} and @var{y}. They are evaluated for
6413 horizontal and vertical chroma subsample values of the output
6414 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6418 the number of input frame, starting from 0
6421 the position in the file of the input frame, NAN if unknown
6424 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6428 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6429 when evaluation is done @emph{per frame}, and will evaluate to NAN
6430 when @option{eval} is set to @samp{init}.
6432 Be aware that frames are taken from each input video in timestamp
6433 order, hence, if their initial timestamps differ, it is a good idea
6434 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6435 have them begin in the same zero timestamp, as the example for
6436 the @var{movie} filter does.
6438 You can chain together more overlays but you should test the
6439 efficiency of such approach.
6441 @subsection Commands
6443 This filter supports the following commands:
6447 Modify the x and y of the overlay input.
6448 The command accepts the same syntax of the corresponding option.
6450 If the specified expression is not valid, it is kept at its current
6454 @subsection Examples
6458 Draw the overlay at 10 pixels from the bottom right corner of the main
6461 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6464 Using named options the example above becomes:
6466 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6470 Insert a transparent PNG logo in the bottom left corner of the input,
6471 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6473 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6477 Insert 2 different transparent PNG logos (second logo on bottom
6478 right corner) using the @command{ffmpeg} tool:
6480 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
6484 Add a transparent color layer on top of the main video; @code{WxH}
6485 must specify the size of the main input to the overlay filter:
6487 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6491 Play an original video and a filtered version (here with the deshake
6492 filter) side by side using the @command{ffplay} tool:
6494 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6497 The above command is the same as:
6499 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6503 Make a sliding overlay appearing from the left to the right top part of the
6504 screen starting since time 2:
6506 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6510 Compose output by putting two input videos side to side:
6512 ffmpeg -i left.avi -i right.avi -filter_complex "
6513 nullsrc=size=200x100 [background];
6514 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6515 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6516 [background][left] overlay=shortest=1 [background+left];
6517 [background+left][right] overlay=shortest=1:x=100 [left+right]
6522 Mask 10-20 seconds of a video by applying the delogo filter to a section
6524 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6525 -vf '[in]split[split_main][split_delogo];[split_delogo]trim=start=360:end=371,delogo=0:0:640:480[delogoed];[split_main][delogoed]overlay=eof_action=pass[out]'
6530 Chain several overlays in cascade:
6532 nullsrc=s=200x200 [bg];
6533 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6534 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6535 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6536 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6537 [in3] null, [mid2] overlay=100:100 [out0]
6544 Apply Overcomplete Wavelet denoiser.
6546 The filter accepts the following options:
6552 Larger depth values will denoise lower frequency components more, but
6553 slow down filtering.
6555 Must be an int in the range 8-16, default is @code{8}.
6557 @item luma_strength, ls
6560 Must be a double value in the range 0-1000, default is @code{1.0}.
6562 @item chroma_strength, cs
6563 Set chroma strength.
6565 Must be a double value in the range 0-1000, default is @code{1.0}.
6570 Add paddings to the input image, and place the original input at the
6571 provided @var{x}, @var{y} coordinates.
6573 It accepts the following parameters:
6578 Specify an expression for the size of the output image with the
6579 paddings added. If the value for @var{width} or @var{height} is 0, the
6580 corresponding input size is used for the output.
6582 The @var{width} expression can reference the value set by the
6583 @var{height} expression, and vice versa.
6585 The default value of @var{width} and @var{height} is 0.
6589 Specify the offsets to place the input image at within the padded area,
6590 with respect to the top/left border of the output image.
6592 The @var{x} expression can reference the value set by the @var{y}
6593 expression, and vice versa.
6595 The default value of @var{x} and @var{y} is 0.
6598 Specify the color of the padded area. For the syntax of this option,
6599 check the "Color" section in the ffmpeg-utils manual.
6601 The default value of @var{color} is "black".
6604 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6605 options are expressions containing the following constants:
6610 The input video width and height.
6614 These are the same as @var{in_w} and @var{in_h}.
6618 The output width and height (the size of the padded area), as
6619 specified by the @var{width} and @var{height} expressions.
6623 These are the same as @var{out_w} and @var{out_h}.
6627 The x and y offsets as specified by the @var{x} and @var{y}
6628 expressions, or NAN if not yet specified.
6631 same as @var{iw} / @var{ih}
6634 input sample aspect ratio
6637 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6641 The horizontal and vertical chroma subsample values. For example for the
6642 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6645 @subsection Examples
6649 Add paddings with the color "violet" to the input video. The output video
6650 size is 640x480, and the top-left corner of the input video is placed at
6653 pad=640:480:0:40:violet
6656 The example above is equivalent to the following command:
6658 pad=width=640:height=480:x=0:y=40:color=violet
6662 Pad the input to get an output with dimensions increased by 3/2,
6663 and put the input video at the center of the padded area:
6665 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6669 Pad the input to get a squared output with size equal to the maximum
6670 value between the input width and height, and put the input video at
6671 the center of the padded area:
6673 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6677 Pad the input to get a final w/h ratio of 16:9:
6679 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6683 In case of anamorphic video, in order to set the output display aspect
6684 correctly, it is necessary to use @var{sar} in the expression,
6685 according to the relation:
6687 (ih * X / ih) * sar = output_dar
6688 X = output_dar / sar
6691 Thus the previous example needs to be modified to:
6693 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6697 Double the output size and put the input video in the bottom-right
6698 corner of the output padded area:
6700 pad="2*iw:2*ih:ow-iw:oh-ih"
6704 @section perspective
6706 Correct perspective of video not recorded perpendicular to the screen.
6708 A description of the accepted parameters follows.
6719 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6720 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6722 The expressions can use the following variables:
6727 the width and height of video frame.
6731 Set interpolation for perspective correction.
6733 It accepts the following values:
6739 Default value is @samp{linear}.
6744 Delay interlaced video by one field time so that the field order changes.
6746 The intended use is to fix PAL movies that have been captured with the
6747 opposite field order to the film-to-video transfer.
6749 A description of the accepted parameters follows.
6755 It accepts the following values:
6758 Capture field order top-first, transfer bottom-first.
6759 Filter will delay the bottom field.
6762 Capture field order bottom-first, transfer top-first.
6763 Filter will delay the top field.
6766 Capture and transfer with the same field order. This mode only exists
6767 for the documentation of the other options to refer to, but if you
6768 actually select it, the filter will faithfully do nothing.
6771 Capture field order determined automatically by field flags, transfer
6773 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6774 basis using field flags. If no field information is available,
6775 then this works just like @samp{u}.
6778 Capture unknown or varying, transfer opposite.
6779 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6780 analyzing the images and selecting the alternative that produces best
6781 match between the fields.
6784 Capture top-first, transfer unknown or varying.
6785 Filter selects among @samp{t} and @samp{p} using image analysis.
6788 Capture bottom-first, transfer unknown or varying.
6789 Filter selects among @samp{b} and @samp{p} using image analysis.
6792 Capture determined by field flags, transfer unknown or varying.
6793 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6794 image analysis. If no field information is available, then this works just
6795 like @samp{U}. This is the default mode.
6798 Both capture and transfer unknown or varying.
6799 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
6803 @section pixdesctest
6805 Pixel format descriptor test filter, mainly useful for internal
6806 testing. The output video should be equal to the input video.
6810 format=monow, pixdesctest
6813 can be used to test the monowhite pixel format descriptor definition.
6817 Enable the specified chain of postprocessing subfilters using libpostproc. This
6818 library should be automatically selected with a GPL build (@code{--enable-gpl}).
6819 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
6820 Each subfilter and some options have a short and a long name that can be used
6821 interchangeably, i.e. dr/dering are the same.
6823 The filters accept the following options:
6827 Set postprocessing subfilters string.
6830 All subfilters share common options to determine their scope:
6834 Honor the quality commands for this subfilter.
6837 Do chrominance filtering, too (default).
6840 Do luminance filtering only (no chrominance).
6843 Do chrominance filtering only (no luminance).
6846 These options can be appended after the subfilter name, separated by a '|'.
6848 Available subfilters are:
6851 @item hb/hdeblock[|difference[|flatness]]
6852 Horizontal deblocking filter
6855 Difference factor where higher values mean more deblocking (default: @code{32}).
6857 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6860 @item vb/vdeblock[|difference[|flatness]]
6861 Vertical deblocking filter
6864 Difference factor where higher values mean more deblocking (default: @code{32}).
6866 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6869 @item ha/hadeblock[|difference[|flatness]]
6870 Accurate horizontal deblocking filter
6873 Difference factor where higher values mean more deblocking (default: @code{32}).
6875 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6878 @item va/vadeblock[|difference[|flatness]]
6879 Accurate vertical deblocking filter
6882 Difference factor where higher values mean more deblocking (default: @code{32}).
6884 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6888 The horizontal and vertical deblocking filters share the difference and
6889 flatness values so you cannot set different horizontal and vertical
6894 Experimental horizontal deblocking filter
6897 Experimental vertical deblocking filter
6902 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
6905 larger -> stronger filtering
6907 larger -> stronger filtering
6909 larger -> stronger filtering
6912 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
6915 Stretch luminance to @code{0-255}.
6918 @item lb/linblenddeint
6919 Linear blend deinterlacing filter that deinterlaces the given block by
6920 filtering all lines with a @code{(1 2 1)} filter.
6922 @item li/linipoldeint
6923 Linear interpolating deinterlacing filter that deinterlaces the given block by
6924 linearly interpolating every second line.
6926 @item ci/cubicipoldeint
6927 Cubic interpolating deinterlacing filter deinterlaces the given block by
6928 cubically interpolating every second line.
6930 @item md/mediandeint
6931 Median deinterlacing filter that deinterlaces the given block by applying a
6932 median filter to every second line.
6934 @item fd/ffmpegdeint
6935 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
6936 second line with a @code{(-1 4 2 4 -1)} filter.
6939 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
6940 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
6942 @item fq/forceQuant[|quantizer]
6943 Overrides the quantizer table from the input with the constant quantizer you
6951 Default pp filter combination (@code{hb|a,vb|a,dr|a})
6954 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
6957 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
6960 @subsection Examples
6964 Apply horizontal and vertical deblocking, deringing and automatic
6965 brightness/contrast:
6971 Apply default filters without brightness/contrast correction:
6977 Apply default filters and temporal denoiser:
6979 pp=default/tmpnoise|1|2|3
6983 Apply deblocking on luminance only, and switch vertical deblocking on or off
6984 automatically depending on available CPU time:
6992 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
6993 Ratio) between two input videos.
6995 This filter takes in input two input videos, the first input is
6996 considered the "main" source and is passed unchanged to the
6997 output. The second input is used as a "reference" video for computing
7000 Both video inputs must have the same resolution and pixel format for
7001 this filter to work correctly. Also it assumes that both inputs
7002 have the same number of frames, which are compared one by one.
7004 The obtained average PSNR is printed through the logging system.
7006 The filter stores the accumulated MSE (mean squared error) of each
7007 frame, and at the end of the processing it is averaged across all frames
7008 equally, and the following formula is applied to obtain the PSNR:
7011 PSNR = 10*log10(MAX^2/MSE)
7014 Where MAX is the average of the maximum values of each component of the
7017 The description of the accepted parameters follows.
7021 If specified the filter will use the named file to save the PSNR of
7022 each individual frame.
7025 The file printed if @var{stats_file} is selected, contains a sequence of
7026 key/value pairs of the form @var{key}:@var{value} for each compared
7029 A description of each shown parameter follows:
7033 sequential number of the input frame, starting from 1
7036 Mean Square Error pixel-by-pixel average difference of the compared
7037 frames, averaged over all the image components.
7039 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
7040 Mean Square Error pixel-by-pixel average difference of the compared
7041 frames for the component specified by the suffix.
7043 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
7044 Peak Signal to Noise ratio of the compared frames for the component
7045 specified by the suffix.
7050 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
7051 [main][ref] psnr="stats_file=stats.log" [out]
7054 On this example the input file being processed is compared with the
7055 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
7056 is stored in @file{stats.log}.
7061 Pulldown reversal (inverse telecine) filter, capable of handling mixed
7062 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
7065 The pullup filter is designed to take advantage of future context in making
7066 its decisions. This filter is stateless in the sense that it does not lock
7067 onto a pattern to follow, but it instead looks forward to the following
7068 fields in order to identify matches and rebuild progressive frames.
7070 To produce content with an even framerate, insert the fps filter after
7071 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
7072 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
7074 The filter accepts the following options:
7081 These options set the amount of "junk" to ignore at the left, right, top, and
7082 bottom of the image, respectively. Left and right are in units of 8 pixels,
7083 while top and bottom are in units of 2 lines.
7084 The default is 8 pixels on each side.
7087 Set the strict breaks. Setting this option to 1 will reduce the chances of
7088 filter generating an occasional mismatched frame, but it may also cause an
7089 excessive number of frames to be dropped during high motion sequences.
7090 Conversely, setting it to -1 will make filter match fields more easily.
7091 This may help processing of video where there is slight blurring between
7092 the fields, but may also cause there to be interlaced frames in the output.
7093 Default value is @code{0}.
7096 Set the metric plane to use. It accepts the following values:
7102 Use chroma blue plane.
7105 Use chroma red plane.
7108 This option may be set to use chroma plane instead of the default luma plane
7109 for doing filter's computations. This may improve accuracy on very clean
7110 source material, but more likely will decrease accuracy, especially if there
7111 is chroma noise (rainbow effect) or any grayscale video.
7112 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
7113 load and make pullup usable in realtime on slow machines.
7116 For best results (without duplicated frames in the output file) it is
7117 necessary to change the output frame rate. For example, to inverse
7118 telecine NTSC input:
7120 ffmpeg -i input -vf pullup -r 24000/1001 ...
7125 Suppress a TV station logo, using an image file to determine which
7126 pixels comprise the logo. It works by filling in the pixels that
7127 comprise the logo with neighboring pixels.
7129 The filter accepts the following options:
7133 Set the filter bitmap file, which can be any image format supported by
7134 libavformat. The width and height of the image file must match those of the
7135 video stream being processed.
7138 Pixels in the provided bitmap image with a value of zero are not
7139 considered part of the logo, non-zero pixels are considered part of
7140 the logo. If you use white (255) for the logo and black (0) for the
7141 rest, you will be safe. For making the filter bitmap, it is
7142 recommended to take a screen capture of a black frame with the logo
7143 visible, and then using a threshold filter followed by the erode
7144 filter once or twice.
7146 If needed, little splotches can be fixed manually. Remember that if
7147 logo pixels are not covered, the filter quality will be much
7148 reduced. Marking too many pixels as part of the logo does not hurt as
7149 much, but it will increase the amount of blurring needed to cover over
7150 the image and will destroy more information than necessary, and extra
7151 pixels will slow things down on a large logo.
7155 Rotate video by an arbitrary angle expressed in radians.
7157 The filter accepts the following options:
7159 A description of the optional parameters follows.
7162 Set an expression for the angle by which to rotate the input video
7163 clockwise, expressed as a number of radians. A negative value will
7164 result in a counter-clockwise rotation. By default it is set to "0".
7166 This expression is evaluated for each frame.
7169 Set the output width expression, default value is "iw".
7170 This expression is evaluated just once during configuration.
7173 Set the output height expression, default value is "ih".
7174 This expression is evaluated just once during configuration.
7177 Enable bilinear interpolation if set to 1, a value of 0 disables
7178 it. Default value is 1.
7181 Set the color used to fill the output area not covered by the rotated
7182 image. For the generalsyntax of this option, check the "Color" section in the
7183 ffmpeg-utils manual. If the special value "none" is selected then no
7184 background is printed (useful for example if the background is never shown).
7186 Default value is "black".
7189 The expressions for the angle and the output size can contain the
7190 following constants and functions:
7194 sequential number of the input frame, starting from 0. It is always NAN
7195 before the first frame is filtered.
7198 time in seconds of the input frame, it is set to 0 when the filter is
7199 configured. It is always NAN before the first frame is filtered.
7203 horizontal and vertical chroma subsample values. For example for the
7204 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7208 the input video width and height
7212 the output width and height, that is the size of the padded area as
7213 specified by the @var{width} and @var{height} expressions
7217 the minimal width/height required for completely containing the input
7218 video rotated by @var{a} radians.
7220 These are only available when computing the @option{out_w} and
7221 @option{out_h} expressions.
7224 @subsection Examples
7228 Rotate the input by PI/6 radians clockwise:
7234 Rotate the input by PI/6 radians counter-clockwise:
7240 Rotate the input by 45 degrees clockwise:
7246 Apply a constant rotation with period T, starting from an angle of PI/3:
7248 rotate=PI/3+2*PI*t/T
7252 Make the input video rotation oscillating with a period of T
7253 seconds and an amplitude of A radians:
7255 rotate=A*sin(2*PI/T*t)
7259 Rotate the video, output size is chosen so that the whole rotating
7260 input video is always completely contained in the output:
7262 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
7266 Rotate the video, reduce the output size so that no background is ever
7269 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
7273 @subsection Commands
7275 The filter supports the following commands:
7279 Set the angle expression.
7280 The command accepts the same syntax of the corresponding option.
7282 If the specified expression is not valid, it is kept at its current
7288 Apply Shape Adaptive Blur.
7290 The filter accepts the following options:
7293 @item luma_radius, lr
7294 Set luma blur filter strength, must be a value in range 0.1-4.0, default
7295 value is 1.0. A greater value will result in a more blurred image, and
7296 in slower processing.
7298 @item luma_pre_filter_radius, lpfr
7299 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
7302 @item luma_strength, ls
7303 Set luma maximum difference between pixels to still be considered, must
7304 be a value in the 0.1-100.0 range, default value is 1.0.
7306 @item chroma_radius, cr
7307 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
7308 greater value will result in a more blurred image, and in slower
7311 @item chroma_pre_filter_radius, cpfr
7312 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
7314 @item chroma_strength, cs
7315 Set chroma maximum difference between pixels to still be considered,
7316 must be a value in the 0.1-100.0 range.
7319 Each chroma option value, if not explicitly specified, is set to the
7320 corresponding luma option value.
7325 Scale (resize) the input video, using the libswscale library.
7327 The scale filter forces the output display aspect ratio to be the same
7328 of the input, by changing the output sample aspect ratio.
7330 If the input image format is different from the format requested by
7331 the next filter, the scale filter will convert the input to the
7335 The filter accepts the following options, or any of the options
7336 supported by the libswscale scaler.
7338 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
7339 the complete list of scaler options.
7344 Set the output video dimension expression. Default value is the input
7347 If the value is 0, the input width is used for the output.
7349 If one of the values is -1, the scale filter will use a value that
7350 maintains the aspect ratio of the input image, calculated from the
7351 other specified dimension. If both of them are -1, the input size is
7354 If one of the values is -n with n > 1, the scale filter will also use a value
7355 that maintains the aspect ratio of the input image, calculated from the other
7356 specified dimension. After that it will, however, make sure that the calculated
7357 dimension is divisible by n and adjust the value if necessary.
7359 See below for the list of accepted constants for use in the dimension
7363 Set the interlacing mode. It accepts the following values:
7367 Force interlaced aware scaling.
7370 Do not apply interlaced scaling.
7373 Select interlaced aware scaling depending on whether the source frames
7374 are flagged as interlaced or not.
7377 Default value is @samp{0}.
7380 Set libswscale scaling flags. See
7381 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7382 complete list of values. If not explicitly specified the filter applies
7386 Set the video size. For the syntax of this option, check the "Video size"
7387 section in the ffmpeg-utils manual.
7389 @item in_color_matrix
7390 @item out_color_matrix
7391 Set in/output YCbCr color space type.
7393 This allows the autodetected value to be overridden as well as allows forcing
7394 a specific value used for the output and encoder.
7396 If not specified, the color space type depends on the pixel format.
7402 Choose automatically.
7405 Format conforming to International Telecommunication Union (ITU)
7406 Recommendation BT.709.
7409 Set color space conforming to the United States Federal Communications
7410 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7413 Set color space conforming to:
7417 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7420 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7423 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7428 Set color space conforming to SMPTE ST 240:1999.
7433 Set in/output YCbCr sample range.
7435 This allows the autodetected value to be overridden as well as allows forcing
7436 a specific value used for the output and encoder. If not specified, the
7437 range depends on the pixel format. Possible values:
7441 Choose automatically.
7444 Set full range (0-255 in case of 8-bit luma).
7447 Set "MPEG" range (16-235 in case of 8-bit luma).
7450 @item force_original_aspect_ratio
7451 Enable decreasing or increasing output video width or height if necessary to
7452 keep the original aspect ratio. Possible values:
7456 Scale the video as specified and disable this feature.
7459 The output video dimensions will automatically be decreased if needed.
7462 The output video dimensions will automatically be increased if needed.
7466 One useful instance of this option is that when you know a specific device's
7467 maximum allowed resolution, you can use this to limit the output video to
7468 that, while retaining the aspect ratio. For example, device A allows
7469 1280x720 playback, and your video is 1920x800. Using this option (set it to
7470 decrease) and specifying 1280x720 to the command line makes the output
7473 Please note that this is a different thing than specifying -1 for @option{w}
7474 or @option{h}, you still need to specify the output resolution for this option
7479 The values of the @option{w} and @option{h} options are expressions
7480 containing the following constants:
7485 The input width and height
7489 These are the same as @var{in_w} and @var{in_h}.
7493 The output (scaled) width and height
7497 These are the same as @var{out_w} and @var{out_h}
7500 The same as @var{iw} / @var{ih}
7503 input sample aspect ratio
7506 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7510 horizontal and vertical input chroma subsample values. For example for the
7511 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7515 horizontal and vertical output chroma subsample values. For example for the
7516 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7519 @subsection Examples
7523 Scale the input video to a size of 200x100
7528 This is equivalent to:
7539 Specify a size abbreviation for the output size:
7544 which can also be written as:
7550 Scale the input to 2x:
7556 The above is the same as:
7562 Scale the input to 2x with forced interlaced scaling:
7564 scale=2*iw:2*ih:interl=1
7568 Scale the input to half size:
7574 Increase the width, and set the height to the same size:
7587 Increase the height, and set the width to 3/2 of the height:
7589 scale=w=3/2*oh:h=3/5*ih
7593 Increase the size, making the size a multiple of the chroma
7596 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7600 Increase the width to a maximum of 500 pixels,
7601 keeping the same aspect ratio as the input:
7603 scale=w='min(500\, iw*3/2):h=-1'
7607 @section separatefields
7609 The @code{separatefields} takes a frame-based video input and splits
7610 each frame into its components fields, producing a new half height clip
7611 with twice the frame rate and twice the frame count.
7613 This filter use field-dominance information in frame to decide which
7614 of each pair of fields to place first in the output.
7615 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7617 @section setdar, setsar
7619 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7622 This is done by changing the specified Sample (aka Pixel) Aspect
7623 Ratio, according to the following equation:
7625 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7628 Keep in mind that the @code{setdar} filter does not modify the pixel
7629 dimensions of the video frame. Also, the display aspect ratio set by
7630 this filter may be changed by later filters in the filterchain,
7631 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7634 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7635 the filter output video.
7637 Note that as a consequence of the application of this filter, the
7638 output display aspect ratio will change according to the equation
7641 Keep in mind that the sample aspect ratio set by the @code{setsar}
7642 filter may be changed by later filters in the filterchain, e.g. if
7643 another "setsar" or a "setdar" filter is applied.
7645 It accepts the following parameters:
7648 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7649 Set the aspect ratio used by the filter.
7651 The parameter can be a floating point number string, an expression, or
7652 a string of the form @var{num}:@var{den}, where @var{num} and
7653 @var{den} are the numerator and denominator of the aspect ratio. If
7654 the parameter is not specified, it is assumed the value "0".
7655 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7659 Set the maximum integer value to use for expressing numerator and
7660 denominator when reducing the expressed aspect ratio to a rational.
7661 Default value is @code{100}.
7665 The parameter @var{sar} is an expression containing
7666 the following constants:
7670 These are approximated values for the mathematical constants e
7671 (Euler's number), pi (Greek pi), and phi (the golden ratio).
7674 The input width and height.
7677 These are the same as @var{w} / @var{h}.
7680 The input sample aspect ratio.
7683 The input display aspect ratio. It is the same as
7684 (@var{w} / @var{h}) * @var{sar}.
7687 Horizontal and vertical chroma subsample values. For example, for the
7688 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7691 @subsection Examples
7696 To change the display aspect ratio to 16:9, specify one of the following:
7704 To change the sample aspect ratio to 10:11, specify:
7710 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7711 1000 in the aspect ratio reduction, use the command:
7713 setdar=ratio=16/9:max=1000
7721 Force field for the output video frame.
7723 The @code{setfield} filter marks the interlace type field for the
7724 output frames. It does not change the input frame, but only sets the
7725 corresponding property, which affects how the frame is treated by
7726 following filters (e.g. @code{fieldorder} or @code{yadif}).
7728 The filter accepts the following options:
7733 Available values are:
7737 Keep the same field property.
7740 Mark the frame as bottom-field-first.
7743 Mark the frame as top-field-first.
7746 Mark the frame as progressive.
7752 Show a line containing various information for each input video frame.
7753 The input video is not modified.
7755 The shown line contains a sequence of key/value pairs of the form
7756 @var{key}:@var{value}.
7758 The following values are shown in the output:
7762 The (sequential) number of the input frame, starting from 0.
7765 The Presentation TimeStamp of the input frame, expressed as a number of
7766 time base units. The time base unit depends on the filter input pad.
7769 The Presentation TimeStamp of the input frame, expressed as a number of
7773 The position of the frame in the input stream, or -1 if this information is
7774 unavailable and/or meaningless (for example in case of synthetic video).
7777 The pixel format name.
7780 The sample aspect ratio of the input frame, expressed in the form
7781 @var{num}/@var{den}.
7784 The size of the input frame. For the syntax of this option, check the "Video size"
7785 section in the ffmpeg-utils manual.
7788 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
7789 for bottom field first).
7792 This is 1 if the frame is a key frame, 0 otherwise.
7795 The picture type of the input frame ("I" for an I-frame, "P" for a
7796 P-frame, "B" for a B-frame, or "?" for an unknown type).
7797 Also refer to the documentation of the @code{AVPictureType} enum and of
7798 the @code{av_get_picture_type_char} function defined in
7799 @file{libavutil/avutil.h}.
7802 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
7804 @item plane_checksum
7805 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
7806 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
7809 @section shuffleplanes
7811 Reorder and/or duplicate video planes.
7813 It accepts the following parameters:
7818 The index of the input plane to be used as the first output plane.
7821 The index of the input plane to be used as the second output plane.
7824 The index of the input plane to be used as the third output plane.
7827 The index of the input plane to be used as the fourth output plane.
7831 The first plane has the index 0. The default is to keep the input unchanged.
7833 Swap the second and third planes of the input:
7835 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
7838 @section signalstats
7839 Evaluate various visual metrics that assist in determining issues associated
7840 with the digitization of analog video media.
7842 By default the filter will log these metadata values:
7846 Display the minimal Y value contained within the input frame. Expressed in
7850 Display the Y value at the 10% percentile within the input frame. Expressed in
7854 Display the average Y value within the input frame. Expressed in range of
7858 Display the Y value at the 90% percentile within the input frame. Expressed in
7862 Display the maximum Y value contained within the input frame. Expressed in
7866 Display the minimal U value contained within the input frame. Expressed in
7870 Display the U value at the 10% percentile within the input frame. Expressed in
7874 Display the average U value within the input frame. Expressed in range of
7878 Display the U value at the 90% percentile within the input frame. Expressed in
7882 Display the maximum U value contained within the input frame. Expressed in
7886 Display the minimal V value contained within the input frame. Expressed in
7890 Display the V value at the 10% percentile within the input frame. Expressed in
7894 Display the average V value within the input frame. Expressed in range of
7898 Display the V value at the 90% percentile within the input frame. Expressed in
7902 Display the maximum V value contained within the input frame. Expressed in
7906 Display the minimal saturation value contained within the input frame.
7907 Expressed in range of [0-~181.02].
7910 Display the saturation value at the 10% percentile within the input frame.
7911 Expressed in range of [0-~181.02].
7914 Display the average saturation value within the input frame. Expressed in range
7918 Display the saturation value at the 90% percentile within the input frame.
7919 Expressed in range of [0-~181.02].
7922 Display the maximum saturation value contained within the input frame.
7923 Expressed in range of [0-~181.02].
7926 Display the median value for hue within the input frame. Expressed in range of
7930 Display the average value for hue within the input frame. Expressed in range of
7934 Display the average of sample value difference between all values of the Y
7935 plane in the current frame and corresponding values of the previous input frame.
7936 Expressed in range of [0-255].
7939 Display the average of sample value difference between all values of the U
7940 plane in the current frame and corresponding values of the previous input frame.
7941 Expressed in range of [0-255].
7944 Display the average of sample value difference between all values of the V
7945 plane in the current frame and corresponding values of the previous input frame.
7946 Expressed in range of [0-255].
7949 The filter accepts the following options:
7955 @option{stat} specify an additional form of image analysis.
7956 @option{out} output video with the specified type of pixel highlighted.
7958 Both options accept the following values:
7962 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
7963 unlike the neighboring pixels of the same field. Examples of temporal outliers
7964 include the results of video dropouts, head clogs, or tape tracking issues.
7967 Identify @var{vertical line repetition}. Vertical line repetition includes
7968 similar rows of pixels within a frame. In born-digital video vertical line
7969 repetition is common, but this pattern is uncommon in video digitized from an
7970 analog source. When it occurs in video that results from the digitization of an
7971 analog source it can indicate concealment from a dropout compensator.
7974 Identify pixels that fall outside of legal broadcast range.
7978 Set the highlight color for the @option{out} option. The default color is
7982 @subsection Examples
7986 Output data of various video metrics:
7988 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
7992 Output specific data about the minimum and maximum values of the Y plane per frame:
7994 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
7998 Playback video while highlighting pixels that are outside of broadcast range in red.
8000 ffplay example.mov -vf signalstats="out=brng:color=red"
8004 Playback video with signalstats metadata drawn over the frame.
8006 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
8009 The contents of signalstat_drawtext.txt used in the command are:
8012 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
8013 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
8014 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
8015 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
8023 Blur the input video without impacting the outlines.
8025 It accepts the following options:
8028 @item luma_radius, lr
8029 Set the luma radius. The option value must be a float number in
8030 the range [0.1,5.0] that specifies the variance of the gaussian filter
8031 used to blur the image (slower if larger). Default value is 1.0.
8033 @item luma_strength, ls
8034 Set the luma strength. The option value must be a float number
8035 in the range [-1.0,1.0] that configures the blurring. A value included
8036 in [0.0,1.0] will blur the image whereas a value included in
8037 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8039 @item luma_threshold, lt
8040 Set the luma threshold used as a coefficient to determine
8041 whether a pixel should be blurred or not. The option value must be an
8042 integer in the range [-30,30]. A value of 0 will filter all the image,
8043 a value included in [0,30] will filter flat areas and a value included
8044 in [-30,0] will filter edges. Default value is 0.
8046 @item chroma_radius, cr
8047 Set the chroma radius. The option value must be a float number in
8048 the range [0.1,5.0] that specifies the variance of the gaussian filter
8049 used to blur the image (slower if larger). Default value is 1.0.
8051 @item chroma_strength, cs
8052 Set the chroma strength. The option value must be a float number
8053 in the range [-1.0,1.0] that configures the blurring. A value included
8054 in [0.0,1.0] will blur the image whereas a value included in
8055 [-1.0,0.0] will sharpen the image. Default value is 1.0.
8057 @item chroma_threshold, ct
8058 Set the chroma threshold used as a coefficient to determine
8059 whether a pixel should be blurred or not. The option value must be an
8060 integer in the range [-30,30]. A value of 0 will filter all the image,
8061 a value included in [0,30] will filter flat areas and a value included
8062 in [-30,0] will filter edges. Default value is 0.
8065 If a chroma option is not explicitly set, the corresponding luma value
8070 Convert between different stereoscopic image formats.
8072 The filters accept the following options:
8076 Set stereoscopic image format of input.
8078 Available values for input image formats are:
8081 side by side parallel (left eye left, right eye right)
8084 side by side crosseye (right eye left, left eye right)
8087 side by side parallel with half width resolution
8088 (left eye left, right eye right)
8091 side by side crosseye with half width resolution
8092 (right eye left, left eye right)
8095 above-below (left eye above, right eye below)
8098 above-below (right eye above, left eye below)
8101 above-below with half height resolution
8102 (left eye above, right eye below)
8105 above-below with half height resolution
8106 (right eye above, left eye below)
8109 alternating frames (left eye first, right eye second)
8112 alternating frames (right eye first, left eye second)
8114 Default value is @samp{sbsl}.
8118 Set stereoscopic image format of output.
8120 Available values for output image formats are all the input formats as well as:
8123 anaglyph red/blue gray
8124 (red filter on left eye, blue filter on right eye)
8127 anaglyph red/green gray
8128 (red filter on left eye, green filter on right eye)
8131 anaglyph red/cyan gray
8132 (red filter on left eye, cyan filter on right eye)
8135 anaglyph red/cyan half colored
8136 (red filter on left eye, cyan filter on right eye)
8139 anaglyph red/cyan color
8140 (red filter on left eye, cyan filter on right eye)
8143 anaglyph red/cyan color optimized with the least squares projection of dubois
8144 (red filter on left eye, cyan filter on right eye)
8147 anaglyph green/magenta gray
8148 (green filter on left eye, magenta filter on right eye)
8151 anaglyph green/magenta half colored
8152 (green filter on left eye, magenta filter on right eye)
8155 anaglyph green/magenta colored
8156 (green filter on left eye, magenta filter on right eye)
8159 anaglyph green/magenta color optimized with the least squares projection of dubois
8160 (green filter on left eye, magenta filter on right eye)
8163 anaglyph yellow/blue gray
8164 (yellow filter on left eye, blue filter on right eye)
8167 anaglyph yellow/blue half colored
8168 (yellow filter on left eye, blue filter on right eye)
8171 anaglyph yellow/blue colored
8172 (yellow filter on left eye, blue filter on right eye)
8175 anaglyph yellow/blue color optimized with the least squares projection of dubois
8176 (yellow filter on left eye, blue filter on right eye)
8179 interleaved rows (left eye has top row, right eye starts on next row)
8182 interleaved rows (right eye has top row, left eye starts on next row)
8185 mono output (left eye only)
8188 mono output (right eye only)
8191 Default value is @samp{arcd}.
8194 @subsection Examples
8198 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
8204 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
8212 Apply a simple postprocessing filter that compresses and decompresses the image
8213 at several (or - in the case of @option{quality} level @code{6} - all) shifts
8214 and average the results.
8216 The filter accepts the following options:
8220 Set quality. This option defines the number of levels for averaging. It accepts
8221 an integer in the range 0-6. If set to @code{0}, the filter will have no
8222 effect. A value of @code{6} means the higher quality. For each increment of
8223 that value the speed drops by a factor of approximately 2. Default value is
8227 Force a constant quantization parameter. If not set, the filter will use the QP
8228 from the video stream (if available).
8231 Set thresholding mode. Available modes are:
8235 Set hard thresholding (default).
8237 Set soft thresholding (better de-ringing effect, but likely blurrier).
8241 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8242 option may cause flicker since the B-Frames have often larger QP. Default is
8243 @code{0} (not enabled).
8249 Draw subtitles on top of input video using the libass library.
8251 To enable compilation of this filter you need to configure FFmpeg with
8252 @code{--enable-libass}. This filter also requires a build with libavcodec and
8253 libavformat to convert the passed subtitles file to ASS (Advanced Substation
8254 Alpha) subtitles format.
8256 The filter accepts the following options:
8260 Set the filename of the subtitle file to read. It must be specified.
8263 Specify the size of the original video, the video for which the ASS file
8264 was composed. For the syntax of this option, check the "Video size" section in
8265 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
8266 this is necessary to correctly scale the fonts if the aspect ratio has been
8270 Set subtitles input character encoding. @code{subtitles} filter only. Only
8271 useful if not UTF-8.
8273 @item stream_index, si
8274 Set subtitles stream index. @code{subtitles} filter only.
8277 If the first key is not specified, it is assumed that the first value
8278 specifies the @option{filename}.
8280 For example, to render the file @file{sub.srt} on top of the input
8281 video, use the command:
8286 which is equivalent to:
8288 subtitles=filename=sub.srt
8291 To render the default subtitles stream from file @file{video.mkv}, use:
8296 To render the second subtitles stream from that file, use:
8298 subtitles=video.mkv:si=1
8303 Scale the input by 2x and smooth using the Super2xSaI (Scale and
8304 Interpolate) pixel art scaling algorithm.
8306 Useful for enlarging pixel art images without reducing sharpness.
8313 Apply telecine process to the video.
8315 This filter accepts the following options:
8324 The default value is @code{top}.
8328 A string of numbers representing the pulldown pattern you wish to apply.
8329 The default value is @code{23}.
8333 Some typical patterns:
8338 24p: 2332 (preferred)
8345 24p: 222222222223 ("Euro pulldown")
8351 Select the most representative frame in a given sequence of consecutive frames.
8353 The filter accepts the following options:
8357 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
8358 will pick one of them, and then handle the next batch of @var{n} frames until
8359 the end. Default is @code{100}.
8362 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
8363 value will result in a higher memory usage, so a high value is not recommended.
8365 @subsection Examples
8369 Extract one picture each 50 frames:
8375 Complete example of a thumbnail creation with @command{ffmpeg}:
8377 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
8383 Tile several successive frames together.
8385 The filter accepts the following options:
8390 Set the grid size (i.e. the number of lines and columns). For the syntax of
8391 this option, check the "Video size" section in the ffmpeg-utils manual.
8394 Set the maximum number of frames to render in the given area. It must be less
8395 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
8396 the area will be used.
8399 Set the outer border margin in pixels.
8402 Set the inner border thickness (i.e. the number of pixels between frames). For
8403 more advanced padding options (such as having different values for the edges),
8404 refer to the pad video filter.
8407 Specify the color of the unused areaFor the syntax of this option, check the
8408 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
8412 @subsection Examples
8416 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
8418 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
8420 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
8421 duplicating each output frame to accommodate the originally detected frame
8425 Display @code{5} pictures in an area of @code{3x2} frames,
8426 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
8427 mixed flat and named options:
8429 tile=3x2:nb_frames=5:padding=7:margin=2
8435 Perform various types of temporal field interlacing.
8437 Frames are counted starting from 1, so the first input frame is
8440 The filter accepts the following options:
8445 Specify the mode of the interlacing. This option can also be specified
8446 as a value alone. See below for a list of values for this option.
8448 Available values are:
8452 Move odd frames into the upper field, even into the lower field,
8453 generating a double height frame at half frame rate.
8456 Only output even frames, odd frames are dropped, generating a frame with
8457 unchanged height at half frame rate.
8460 Only output odd frames, even frames are dropped, generating a frame with
8461 unchanged height at half frame rate.
8464 Expand each frame to full height, but pad alternate lines with black,
8465 generating a frame with double height at the same input frame rate.
8467 @item interleave_top, 4
8468 Interleave the upper field from odd frames with the lower field from
8469 even frames, generating a frame with unchanged height at half frame rate.
8471 @item interleave_bottom, 5
8472 Interleave the lower field from odd frames with the upper field from
8473 even frames, generating a frame with unchanged height at half frame rate.
8475 @item interlacex2, 6
8476 Double frame rate with unchanged height. Frames are inserted each
8477 containing the second temporal field from the previous input frame and
8478 the first temporal field from the next input frame. This mode relies on
8479 the top_field_first flag. Useful for interlaced video displays with no
8480 field synchronisation.
8483 Numeric values are deprecated but are accepted for backward
8484 compatibility reasons.
8486 Default mode is @code{merge}.
8489 Specify flags influencing the filter process.
8491 Available value for @var{flags} is:
8494 @item low_pass_filter, vlfp
8495 Enable vertical low-pass filtering in the filter.
8496 Vertical low-pass filtering is required when creating an interlaced
8497 destination from a progressive source which contains high-frequency
8498 vertical detail. Filtering will reduce interlace 'twitter' and Moire
8501 Vertical low-pass filtering can only be enabled for @option{mode}
8502 @var{interleave_top} and @var{interleave_bottom}.
8509 Transpose rows with columns in the input video and optionally flip it.
8511 It accepts the following parameters:
8516 Specify the transposition direction.
8518 Can assume the following values:
8520 @item 0, 4, cclock_flip
8521 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
8529 Rotate by 90 degrees clockwise, that is:
8537 Rotate by 90 degrees counterclockwise, that is:
8544 @item 3, 7, clock_flip
8545 Rotate by 90 degrees clockwise and vertically flip, that is:
8553 For values between 4-7, the transposition is only done if the input
8554 video geometry is portrait and not landscape. These values are
8555 deprecated, the @code{passthrough} option should be used instead.
8557 Numerical values are deprecated, and should be dropped in favor of
8561 Do not apply the transposition if the input geometry matches the one
8562 specified by the specified value. It accepts the following values:
8565 Always apply transposition.
8567 Preserve portrait geometry (when @var{height} >= @var{width}).
8569 Preserve landscape geometry (when @var{width} >= @var{height}).
8572 Default value is @code{none}.
8575 For example to rotate by 90 degrees clockwise and preserve portrait
8578 transpose=dir=1:passthrough=portrait
8581 The command above can also be specified as:
8583 transpose=1:portrait
8587 Trim the input so that the output contains one continuous subpart of the input.
8589 It accepts the following parameters:
8592 Specify the time of the start of the kept section, i.e. the frame with the
8593 timestamp @var{start} will be the first frame in the output.
8596 Specify the time of the first frame that will be dropped, i.e. the frame
8597 immediately preceding the one with the timestamp @var{end} will be the last
8598 frame in the output.
8601 This is the same as @var{start}, except this option sets the start timestamp
8602 in timebase units instead of seconds.
8605 This is the same as @var{end}, except this option sets the end timestamp
8606 in timebase units instead of seconds.
8609 The maximum duration of the output in seconds.
8612 The number of the first frame that should be passed to the output.
8615 The number of the first frame that should be dropped.
8618 @option{start}, @option{end}, and @option{duration} are expressed as time
8619 duration specifications; see
8620 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
8621 for the accepted syntax.
8623 Note that the first two sets of the start/end options and the @option{duration}
8624 option look at the frame timestamp, while the _frame variants simply count the
8625 frames that pass through the filter. Also note that this filter does not modify
8626 the timestamps. If you wish for the output timestamps to start at zero, insert a
8627 setpts filter after the trim filter.
8629 If multiple start or end options are set, this filter tries to be greedy and
8630 keep all the frames that match at least one of the specified constraints. To keep
8631 only the part that matches all the constraints at once, chain multiple trim
8634 The defaults are such that all the input is kept. So it is possible to set e.g.
8635 just the end values to keep everything before the specified time.
8640 Drop everything except the second minute of input:
8642 ffmpeg -i INPUT -vf trim=60:120
8646 Keep only the first second:
8648 ffmpeg -i INPUT -vf trim=duration=1
8656 Sharpen or blur the input video.
8658 It accepts the following parameters:
8661 @item luma_msize_x, lx
8662 Set the luma matrix horizontal size. It must be an odd integer between
8663 3 and 63. The default value is 5.
8665 @item luma_msize_y, ly
8666 Set the luma matrix vertical size. It must be an odd integer between 3
8667 and 63. The default value is 5.
8669 @item luma_amount, la
8670 Set the luma effect strength. It must be a floating point number, reasonable
8671 values lay between -1.5 and 1.5.
8673 Negative values will blur the input video, while positive values will
8674 sharpen it, a value of zero will disable the effect.
8676 Default value is 1.0.
8678 @item chroma_msize_x, cx
8679 Set the chroma matrix horizontal size. It must be an odd integer
8680 between 3 and 63. The default value is 5.
8682 @item chroma_msize_y, cy
8683 Set the chroma matrix vertical size. It must be an odd integer
8684 between 3 and 63. The default value is 5.
8686 @item chroma_amount, ca
8687 Set the chroma effect strength. It must be a floating point number, reasonable
8688 values lay between -1.5 and 1.5.
8690 Negative values will blur the input video, while positive values will
8691 sharpen it, a value of zero will disable the effect.
8693 Default value is 0.0.
8696 If set to 1, specify using OpenCL capabilities, only available if
8697 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
8701 All parameters are optional and default to the equivalent of the
8702 string '5:5:1.0:5:5:0.0'.
8704 @subsection Examples
8708 Apply strong luma sharpen effect:
8710 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
8714 Apply a strong blur of both luma and chroma parameters:
8716 unsharp=7:7:-2:7:7:-2
8720 @anchor{vidstabdetect}
8721 @section vidstabdetect
8723 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
8724 @ref{vidstabtransform} for pass 2.
8726 This filter generates a file with relative translation and rotation
8727 transform information about subsequent frames, which is then used by
8728 the @ref{vidstabtransform} filter.
8730 To enable compilation of this filter you need to configure FFmpeg with
8731 @code{--enable-libvidstab}.
8733 This filter accepts the following options:
8737 Set the path to the file used to write the transforms information.
8738 Default value is @file{transforms.trf}.
8741 Set how shaky the video is and how quick the camera is. It accepts an
8742 integer in the range 1-10, a value of 1 means little shakiness, a
8743 value of 10 means strong shakiness. Default value is 5.
8746 Set the accuracy of the detection process. It must be a value in the
8747 range 1-15. A value of 1 means low accuracy, a value of 15 means high
8748 accuracy. Default value is 15.
8751 Set stepsize of the search process. The region around minimum is
8752 scanned with 1 pixel resolution. Default value is 6.
8755 Set minimum contrast. Below this value a local measurement field is
8756 discarded. Must be a floating point value in the range 0-1. Default
8760 Set reference frame number for tripod mode.
8762 If enabled, the motion of the frames is compared to a reference frame
8763 in the filtered stream, identified by the specified number. The idea
8764 is to compensate all movements in a more-or-less static scene and keep
8765 the camera view absolutely still.
8767 If set to 0, it is disabled. The frames are counted starting from 1.
8770 Show fields and transforms in the resulting frames. It accepts an
8771 integer in the range 0-2. Default value is 0, which disables any
8775 @subsection Examples
8785 Analyze strongly shaky movie and put the results in file
8786 @file{mytransforms.trf}:
8788 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
8792 Visualize the result of internal transformations in the resulting
8795 vidstabdetect=show=1
8799 Analyze a video with medium shakiness using @command{ffmpeg}:
8801 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
8805 @anchor{vidstabtransform}
8806 @section vidstabtransform
8808 Video stabilization/deshaking: pass 2 of 2,
8809 see @ref{vidstabdetect} for pass 1.
8811 Read a file with transform information for each frame and
8812 apply/compensate them. Together with the @ref{vidstabdetect}
8813 filter this can be used to deshake videos. See also
8814 @url{http://public.hronopik.de/vid.stab}. It is important to also use
8815 the unsharp filter, see below.
8817 To enable compilation of this filter you need to configure FFmpeg with
8818 @code{--enable-libvidstab}.
8824 Set path to the file used to read the transforms. Default value is
8825 @file{transforms.trf}).
8828 Set the number of frames (value*2 + 1) used for lowpass filtering the
8829 camera movements. Default value is 10.
8831 For example a number of 10 means that 21 frames are used (10 in the
8832 past and 10 in the future) to smoothen the motion in the video. A
8833 larger values leads to a smoother video, but limits the acceleration
8834 of the camera (pan/tilt movements). 0 is a special case where a
8835 static camera is simulated.
8838 Set the camera path optimization algorithm.
8840 Accepted values are:
8843 gaussian kernel low-pass filter on camera motion (default)
8845 averaging on transformations
8849 Set maximal number of pixels to translate frames. Default value is -1,
8853 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
8854 value is -1, meaning no limit.
8857 Specify how to deal with borders that may be visible due to movement
8860 Available values are:
8863 keep image information from previous frame (default)
8865 fill the border black
8869 Invert transforms if set to 1. Default value is 0.
8872 Consider transforms as relative to previsou frame if set to 1,
8873 absolute if set to 0. Default value is 0.
8876 Set percentage to zoom. A positive value will result in a zoom-in
8877 effect, a negative value in a zoom-out effect. Default value is 0 (no
8881 Set optimal zooming to avoid borders.
8883 Accepted values are:
8888 optimal static zoom value is determined (only very strong movements
8889 will lead to visible borders) (default)
8891 optimal adaptive zoom value is determined (no borders will be
8892 visible), see @option{zoomspeed}
8895 Note that the value given at zoom is added to the one calculated here.
8898 Set percent to zoom maximally each frame (enabled when
8899 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
8903 Specify type of interpolation.
8905 Available values are:
8910 linear only horizontal
8912 linear in both directions (default)
8914 cubic in both directions (slow)
8918 Enable virtual tripod mode if set to 1, which is equivalent to
8919 @code{relative=0:smoothing=0}. Default value is 0.
8921 Use also @code{tripod} option of @ref{vidstabdetect}.
8924 Increase log verbosity if set to 1. Also the detected global motions
8925 are written to the temporary file @file{global_motions.trf}. Default
8929 @subsection Examples
8933 Use @command{ffmpeg} for a typical stabilization with default values:
8935 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
8938 Note the use of the unsharp filter which is always recommended.
8941 Zoom in a bit more and load transform data from a given file:
8943 vidstabtransform=zoom=5:input="mytransforms.trf"
8947 Smoothen the video even more:
8949 vidstabtransform=smoothing=30
8955 Flip the input video vertically.
8957 For example, to vertically flip a video with @command{ffmpeg}:
8959 ffmpeg -i in.avi -vf "vflip" out.avi
8965 Make or reverse a natural vignetting effect.
8967 The filter accepts the following options:
8971 Set lens angle expression as a number of radians.
8973 The value is clipped in the @code{[0,PI/2]} range.
8975 Default value: @code{"PI/5"}
8979 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
8983 Set forward/backward mode.
8985 Available modes are:
8988 The larger the distance from the central point, the darker the image becomes.
8991 The larger the distance from the central point, the brighter the image becomes.
8992 This can be used to reverse a vignette effect, though there is no automatic
8993 detection to extract the lens @option{angle} and other settings (yet). It can
8994 also be used to create a burning effect.
8997 Default value is @samp{forward}.
9000 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
9002 It accepts the following values:
9005 Evaluate expressions only once during the filter initialization.
9008 Evaluate expressions for each incoming frame. This is way slower than the
9009 @samp{init} mode since it requires all the scalers to be re-computed, but it
9010 allows advanced dynamic expressions.
9013 Default value is @samp{init}.
9016 Set dithering to reduce the circular banding effects. Default is @code{1}
9020 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
9021 Setting this value to the SAR of the input will make a rectangular vignetting
9022 following the dimensions of the video.
9024 Default is @code{1/1}.
9027 @subsection Expressions
9029 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
9030 following parameters.
9035 input width and height
9038 the number of input frame, starting from 0
9041 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
9042 @var{TB} units, NAN if undefined
9045 frame rate of the input video, NAN if the input frame rate is unknown
9048 the PTS (Presentation TimeStamp) of the filtered video frame,
9049 expressed in seconds, NAN if undefined
9052 time base of the input video
9056 @subsection Examples
9060 Apply simple strong vignetting effect:
9066 Make a flickering vignetting:
9068 vignette='PI/4+random(1)*PI/50':eval=frame
9075 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
9076 Deinterlacing Filter").
9078 Based on the process described by Martin Weston for BBC R&D, and
9079 implemented based on the de-interlace algorithm written by Jim
9080 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
9081 uses filter coefficients calculated by BBC R&D.
9083 There are two sets of filter coefficients, so called "simple":
9084 and "complex". Which set of filter coefficients is used can
9085 be set by passing an optional parameter:
9089 Set the interlacing filter coefficients. Accepts one of the following values:
9093 Simple filter coefficient set.
9095 More-complex filter coefficient set.
9097 Default value is @samp{complex}.
9100 Specify which frames to deinterlace. Accept one of the following values:
9104 Deinterlace all frames,
9106 Only deinterlace frames marked as interlaced.
9109 Default value is @samp{all}.
9115 Deinterlace the input video ("yadif" means "yet another deinterlacing
9118 It accepts the following parameters:
9124 The interlacing mode to adopt. It accepts one of the following values:
9128 Output one frame for each frame.
9130 Output one frame for each field.
9131 @item 2, send_frame_nospatial
9132 Like @code{send_frame}, but it skips the spatial interlacing check.
9133 @item 3, send_field_nospatial
9134 Like @code{send_field}, but it skips the spatial interlacing check.
9137 The default value is @code{send_frame}.
9140 The picture field parity assumed for the input interlaced video. It accepts one
9141 of the following values:
9145 Assume the top field is first.
9147 Assume the bottom field is first.
9149 Enable automatic detection of field parity.
9152 The default value is @code{auto}.
9153 If the interlacing is unknown or the decoder does not export this information,
9154 top field first will be assumed.
9157 Specify which frames to deinterlace. Accept one of the following
9162 Deinterlace all frames.
9164 Only deinterlace frames marked as interlaced.
9167 The default value is @code{all}.
9172 Apply Zoom & Pan effect.
9174 This filter accepts the following options:
9178 Set the zoom expression. Default is 1.
9182 Set the x and y expression. Default is 0.
9185 Set the duration expression in number of frames.
9186 This sets for how many number of frames effect will last for
9190 Set the output image size, default is 'hd720'.
9193 Each expression can contain the following constants:
9216 Last calculated 'x' and 'y' position from 'x' and 'y' expression
9217 for current input frame.
9221 'x' and 'y' of last output frame of previous input frame or 0 when there was
9222 not yet such frame (first input frame).
9225 Last calculated zoom from 'z' expression for current input frame.
9228 Last calculated zoom of last output frame of previous input frame.
9231 Number of output frames for current input frame. Calculated from 'd' expression
9232 for each input frame.
9235 number of output frames created for previous input frame
9238 Rational number: input width / input height
9244 display aspect ratio
9248 @subsection Examples
9252 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
9254 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='if(gte(zoom,1.5),x,x+1/a)':y='if(gte(zoom,1.5),y,y+1)':s=640x360
9258 @c man end VIDEO FILTERS
9260 @chapter Video Sources
9261 @c man begin VIDEO SOURCES
9263 Below is a description of the currently available video sources.
9267 Buffer video frames, and make them available to the filter chain.
9269 This source is mainly intended for a programmatic use, in particular
9270 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
9272 It accepts the following parameters:
9277 Specify the size (width and height) of the buffered video frames. For the
9278 syntax of this option, check the "Video size" section in the ffmpeg-utils
9282 The input video width.
9285 The input video height.
9288 A string representing the pixel format of the buffered video frames.
9289 It may be a number corresponding to a pixel format, or a pixel format
9293 Specify the timebase assumed by the timestamps of the buffered frames.
9296 Specify the frame rate expected for the video stream.
9298 @item pixel_aspect, sar
9299 The sample (pixel) aspect ratio of the input video.
9302 Specify the optional parameters to be used for the scale filter which
9303 is automatically inserted when an input change is detected in the
9304 input size or format.
9309 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
9312 will instruct the source to accept video frames with size 320x240 and
9313 with format "yuv410p", assuming 1/24 as the timestamps timebase and
9314 square pixels (1:1 sample aspect ratio).
9315 Since the pixel format with name "yuv410p" corresponds to the number 6
9316 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
9317 this example corresponds to:
9319 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
9322 Alternatively, the options can be specified as a flat string, but this
9323 syntax is deprecated:
9325 @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}]
9329 Create a pattern generated by an elementary cellular automaton.
9331 The initial state of the cellular automaton can be defined through the
9332 @option{filename}, and @option{pattern} options. If such options are
9333 not specified an initial state is created randomly.
9335 At each new frame a new row in the video is filled with the result of
9336 the cellular automaton next generation. The behavior when the whole
9337 frame is filled is defined by the @option{scroll} option.
9339 This source accepts the following options:
9343 Read the initial cellular automaton state, i.e. the starting row, from
9345 In the file, each non-whitespace character is considered an alive
9346 cell, a newline will terminate the row, and further characters in the
9347 file will be ignored.
9350 Read the initial cellular automaton state, i.e. the starting row, from
9351 the specified string.
9353 Each non-whitespace character in the string is considered an alive
9354 cell, a newline will terminate the row, and further characters in the
9355 string will be ignored.
9358 Set the video rate, that is the number of frames generated per second.
9361 @item random_fill_ratio, ratio
9362 Set the random fill ratio for the initial cellular automaton row. It
9363 is a floating point number value ranging from 0 to 1, defaults to
9366 This option is ignored when a file or a pattern is specified.
9368 @item random_seed, seed
9369 Set the seed for filling randomly the initial row, must be an integer
9370 included between 0 and UINT32_MAX. If not specified, or if explicitly
9371 set to -1, the filter will try to use a good random seed on a best
9375 Set the cellular automaton rule, it is a number ranging from 0 to 255.
9376 Default value is 110.
9379 Set the size of the output video. For the syntax of this option, check
9380 the "Video size" section in the ffmpeg-utils manual.
9382 If @option{filename} or @option{pattern} is specified, the size is set
9383 by default to the width of the specified initial state row, and the
9384 height is set to @var{width} * PHI.
9386 If @option{size} is set, it must contain the width of the specified
9387 pattern string, and the specified pattern will be centered in the
9390 If a filename or a pattern string is not specified, the size value
9391 defaults to "320x518" (used for a randomly generated initial state).
9394 If set to 1, scroll the output upward when all the rows in the output
9395 have been already filled. If set to 0, the new generated row will be
9396 written over the top row just after the bottom row is filled.
9399 @item start_full, full
9400 If set to 1, completely fill the output with generated rows before
9401 outputting the first frame.
9402 This is the default behavior, for disabling set the value to 0.
9405 If set to 1, stitch the left and right row edges together.
9406 This is the default behavior, for disabling set the value to 0.
9409 @subsection Examples
9413 Read the initial state from @file{pattern}, and specify an output of
9416 cellauto=f=pattern:s=200x400
9420 Generate a random initial row with a width of 200 cells, with a fill
9423 cellauto=ratio=2/3:s=200x200
9427 Create a pattern generated by rule 18 starting by a single alive cell
9428 centered on an initial row with width 100:
9430 cellauto=p=@@:s=100x400:full=0:rule=18
9434 Specify a more elaborated initial pattern:
9436 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
9443 Generate a Mandelbrot set fractal, and progressively zoom towards the
9444 point specified with @var{start_x} and @var{start_y}.
9446 This source accepts the following options:
9451 Set the terminal pts value. Default value is 400.
9454 Set the terminal scale value.
9455 Must be a floating point value. Default value is 0.3.
9458 Set the inner coloring mode, that is the algorithm used to draw the
9459 Mandelbrot fractal internal region.
9461 It shall assume one of the following values:
9466 Show time until convergence.
9468 Set color based on point closest to the origin of the iterations.
9473 Default value is @var{mincol}.
9476 Set the bailout value. Default value is 10.0.
9479 Set the maximum of iterations performed by the rendering
9480 algorithm. Default value is 7189.
9483 Set outer coloring mode.
9484 It shall assume one of following values:
9486 @item iteration_count
9487 Set iteration cound mode.
9488 @item normalized_iteration_count
9489 set normalized iteration count mode.
9491 Default value is @var{normalized_iteration_count}.
9494 Set frame rate, expressed as number of frames per second. Default
9498 Set frame size. For the syntax of this option, check the "Video
9499 size" section in the ffmpeg-utils manual. Default value is "640x480".
9502 Set the initial scale value. Default value is 3.0.
9505 Set the initial x position. Must be a floating point value between
9506 -100 and 100. Default value is -0.743643887037158704752191506114774.
9509 Set the initial y position. Must be a floating point value between
9510 -100 and 100. Default value is -0.131825904205311970493132056385139.
9515 Generate various test patterns, as generated by the MPlayer test filter.
9517 The size of the generated video is fixed, and is 256x256.
9518 This source is useful in particular for testing encoding features.
9520 This source accepts the following options:
9525 Specify the frame rate of the sourced video, as the number of frames
9526 generated per second. It has to be a string in the format
9527 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9528 number or a valid video frame rate abbreviation. The default value is
9532 Set the duration of the sourced video. See
9533 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
9534 for the accepted syntax.
9536 If not specified, or the expressed duration is negative, the video is
9537 supposed to be generated forever.
9541 Set the number or the name of the test to perform. Supported tests are:
9557 Default value is "all", which will cycle through the list of all tests.
9565 will generate a "dc_luma" test pattern.
9569 Provide a frei0r source.
9571 To enable compilation of this filter you need to install the frei0r
9572 header and configure FFmpeg with @code{--enable-frei0r}.
9574 This source accepts the following parameters:
9579 The size of the video to generate. For the syntax of this option, check the
9580 "Video size" section in the ffmpeg-utils manual.
9583 The framerate of the generated video. It may be a string of the form
9584 @var{num}/@var{den} or a frame rate abbreviation.
9587 The name to the frei0r source to load. For more information regarding frei0r and
9588 how to set the parameters, read the @ref{frei0r} section in the video filters
9592 A '|'-separated list of parameters to pass to the frei0r source.
9596 For example, to generate a frei0r partik0l source with size 200x200
9597 and frame rate 10 which is overlayed on the overlay filter main input:
9599 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
9604 Generate a life pattern.
9606 This source is based on a generalization of John Conway's life game.
9608 The sourced input represents a life grid, each pixel represents a cell
9609 which can be in one of two possible states, alive or dead. Every cell
9610 interacts with its eight neighbours, which are the cells that are
9611 horizontally, vertically, or diagonally adjacent.
9613 At each interaction the grid evolves according to the adopted rule,
9614 which specifies the number of neighbor alive cells which will make a
9615 cell stay alive or born. The @option{rule} option allows one to specify
9618 This source accepts the following options:
9622 Set the file from which to read the initial grid state. In the file,
9623 each non-whitespace character is considered an alive cell, and newline
9624 is used to delimit the end of each row.
9626 If this option is not specified, the initial grid is generated
9630 Set the video rate, that is the number of frames generated per second.
9633 @item random_fill_ratio, ratio
9634 Set the random fill ratio for the initial random grid. It is a
9635 floating point number value ranging from 0 to 1, defaults to 1/PHI.
9636 It is ignored when a file is specified.
9638 @item random_seed, seed
9639 Set the seed for filling the initial random grid, must be an integer
9640 included between 0 and UINT32_MAX. If not specified, or if explicitly
9641 set to -1, the filter will try to use a good random seed on a best
9647 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
9648 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
9649 @var{NS} specifies the number of alive neighbor cells which make a
9650 live cell stay alive, and @var{NB} the number of alive neighbor cells
9651 which make a dead cell to become alive (i.e. to "born").
9652 "s" and "b" can be used in place of "S" and "B", respectively.
9654 Alternatively a rule can be specified by an 18-bits integer. The 9
9655 high order bits are used to encode the next cell state if it is alive
9656 for each number of neighbor alive cells, the low order bits specify
9657 the rule for "borning" new cells. Higher order bits encode for an
9658 higher number of neighbor cells.
9659 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
9660 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
9662 Default value is "S23/B3", which is the original Conway's game of life
9663 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
9664 cells, and will born a new cell if there are three alive cells around
9668 Set the size of the output video. For the syntax of this option, check the
9669 "Video size" section in the ffmpeg-utils manual.
9671 If @option{filename} is specified, the size is set by default to the
9672 same size of the input file. If @option{size} is set, it must contain
9673 the size specified in the input file, and the initial grid defined in
9674 that file is centered in the larger resulting area.
9676 If a filename is not specified, the size value defaults to "320x240"
9677 (used for a randomly generated initial grid).
9680 If set to 1, stitch the left and right grid edges together, and the
9681 top and bottom edges also. Defaults to 1.
9684 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
9685 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
9686 value from 0 to 255.
9689 Set the color of living (or new born) cells.
9692 Set the color of dead cells. If @option{mold} is set, this is the first color
9693 used to represent a dead cell.
9696 Set mold color, for definitely dead and moldy cells.
9698 For the syntax of these 3 color options, check the "Color" section in the
9699 ffmpeg-utils manual.
9702 @subsection Examples
9706 Read a grid from @file{pattern}, and center it on a grid of size
9709 life=f=pattern:s=300x300
9713 Generate a random grid of size 200x200, with a fill ratio of 2/3:
9715 life=ratio=2/3:s=200x200
9719 Specify a custom rule for evolving a randomly generated grid:
9725 Full example with slow death effect (mold) using @command{ffplay}:
9727 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
9732 @anchor{haldclutsrc}
9736 @anchor{smptehdbars}
9738 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
9740 The @code{color} source provides an uniformly colored input.
9742 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
9743 @ref{haldclut} filter.
9745 The @code{nullsrc} source returns unprocessed video frames. It is
9746 mainly useful to be employed in analysis / debugging tools, or as the
9747 source for filters which ignore the input data.
9749 The @code{rgbtestsrc} source generates an RGB test pattern useful for
9750 detecting RGB vs BGR issues. You should see a red, green and blue
9751 stripe from top to bottom.
9753 The @code{smptebars} source generates a color bars pattern, based on
9754 the SMPTE Engineering Guideline EG 1-1990.
9756 The @code{smptehdbars} source generates a color bars pattern, based on
9757 the SMPTE RP 219-2002.
9759 The @code{testsrc} source generates a test video pattern, showing a
9760 color pattern, a scrolling gradient and a timestamp. This is mainly
9761 intended for testing purposes.
9763 The sources accept the following parameters:
9768 Specify the color of the source, only available in the @code{color}
9769 source. For the syntax of this option, check the "Color" section in the
9770 ffmpeg-utils manual.
9773 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
9774 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
9775 pixels to be used as identity matrix for 3D lookup tables. Each component is
9776 coded on a @code{1/(N*N)} scale.
9779 Specify the size of the sourced video. For the syntax of this option, check the
9780 "Video size" section in the ffmpeg-utils manual. The default value is
9783 This option is not available with the @code{haldclutsrc} filter.
9786 Specify the frame rate of the sourced video, as the number of frames
9787 generated per second. It has to be a string in the format
9788 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9789 number or a valid video frame rate abbreviation. The default value is
9793 Set the sample aspect ratio of the sourced video.
9796 Set the duration of the sourced video. See
9797 @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}
9798 for the accepted syntax.
9800 If not specified, or the expressed duration is negative, the video is
9801 supposed to be generated forever.
9804 Set the number of decimals to show in the timestamp, only available in the
9805 @code{testsrc} source.
9807 The displayed timestamp value will correspond to the original
9808 timestamp value multiplied by the power of 10 of the specified
9809 value. Default value is 0.
9812 For example the following:
9814 testsrc=duration=5.3:size=qcif:rate=10
9817 will generate a video with a duration of 5.3 seconds, with size
9818 176x144 and a frame rate of 10 frames per second.
9820 The following graph description will generate a red source
9821 with an opacity of 0.2, with size "qcif" and a frame rate of 10
9824 color=c=red@@0.2:s=qcif:r=10
9827 If the input content is to be ignored, @code{nullsrc} can be used. The
9828 following command generates noise in the luminance plane by employing
9829 the @code{geq} filter:
9831 nullsrc=s=256x256, geq=random(1)*255:128:128
9834 @subsection Commands
9836 The @code{color} source supports the following commands:
9840 Set the color of the created image. Accepts the same syntax of the
9841 corresponding @option{color} option.
9844 @c man end VIDEO SOURCES
9846 @chapter Video Sinks
9847 @c man begin VIDEO SINKS
9849 Below is a description of the currently available video sinks.
9853 Buffer video frames, and make them available to the end of the filter
9856 This sink is mainly intended for programmatic use, in particular
9857 through the interface defined in @file{libavfilter/buffersink.h}
9858 or the options system.
9860 It accepts a pointer to an AVBufferSinkContext structure, which
9861 defines the incoming buffers' formats, to be passed as the opaque
9862 parameter to @code{avfilter_init_filter} for initialization.
9866 Null video sink: do absolutely nothing with the input video. It is
9867 mainly useful as a template and for use in analysis / debugging
9870 @c man end VIDEO SINKS
9872 @chapter Multimedia Filters
9873 @c man begin MULTIMEDIA FILTERS
9875 Below is a description of the currently available multimedia filters.
9877 @section avectorscope
9879 Convert input audio to a video output, representing the audio vector
9882 The filter is used to measure the difference between channels of stereo
9883 audio stream. A monoaural signal, consisting of identical left and right
9884 signal, results in straight vertical line. Any stereo separation is visible
9885 as a deviation from this line, creating a Lissajous figure.
9886 If the straight (or deviation from it) but horizontal line appears this
9887 indicates that the left and right channels are out of phase.
9889 The filter accepts the following options:
9893 Set the vectorscope mode.
9895 Available values are:
9898 Lissajous rotated by 45 degrees.
9901 Same as above but not rotated.
9904 Default value is @samp{lissajous}.
9907 Set the video size for the output. For the syntax of this option, check the "Video size"
9908 section in the ffmpeg-utils manual. Default value is @code{400x400}.
9911 Set the output frame rate. Default value is @code{25}.
9916 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
9917 Allowed range is @code{[0, 255]}.
9922 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
9923 Allowed range is @code{[0, 255]}.
9926 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
9929 @subsection Examples
9933 Complete example using @command{ffplay}:
9935 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9936 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
9942 Concatenate audio and video streams, joining them together one after the
9945 The filter works on segments of synchronized video and audio streams. All
9946 segments must have the same number of streams of each type, and that will
9947 also be the number of streams at output.
9949 The filter accepts the following options:
9954 Set the number of segments. Default is 2.
9957 Set the number of output video streams, that is also the number of video
9958 streams in each segment. Default is 1.
9961 Set the number of output audio streams, that is also the number of audio
9962 streams in each segment. Default is 0.
9965 Activate unsafe mode: do not fail if segments have a different format.
9969 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
9970 @var{a} audio outputs.
9972 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
9973 segment, in the same order as the outputs, then the inputs for the second
9976 Related streams do not always have exactly the same duration, for various
9977 reasons including codec frame size or sloppy authoring. For that reason,
9978 related synchronized streams (e.g. a video and its audio track) should be
9979 concatenated at once. The concat filter will use the duration of the longest
9980 stream in each segment (except the last one), and if necessary pad shorter
9981 audio streams with silence.
9983 For this filter to work correctly, all segments must start at timestamp 0.
9985 All corresponding streams must have the same parameters in all segments; the
9986 filtering system will automatically select a common pixel format for video
9987 streams, and a common sample format, sample rate and channel layout for
9988 audio streams, but other settings, such as resolution, must be converted
9989 explicitly by the user.
9991 Different frame rates are acceptable but will result in variable frame rate
9992 at output; be sure to configure the output file to handle it.
9994 @subsection Examples
9998 Concatenate an opening, an episode and an ending, all in bilingual version
9999 (video in stream 0, audio in streams 1 and 2):
10001 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
10002 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
10003 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
10004 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
10008 Concatenate two parts, handling audio and video separately, using the
10009 (a)movie sources, and adjusting the resolution:
10011 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
10012 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
10013 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
10015 Note that a desync will happen at the stitch if the audio and video streams
10016 do not have exactly the same duration in the first file.
10022 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
10023 it unchanged. By default, it logs a message at a frequency of 10Hz with the
10024 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
10025 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
10027 The filter also has a video output (see the @var{video} option) with a real
10028 time graph to observe the loudness evolution. The graphic contains the logged
10029 message mentioned above, so it is not printed anymore when this option is set,
10030 unless the verbose logging is set. The main graphing area contains the
10031 short-term loudness (3 seconds of analysis), and the gauge on the right is for
10032 the momentary loudness (400 milliseconds).
10034 More information about the Loudness Recommendation EBU R128 on
10035 @url{http://tech.ebu.ch/loudness}.
10037 The filter accepts the following options:
10042 Activate the video output. The audio stream is passed unchanged whether this
10043 option is set or no. The video stream will be the first output stream if
10044 activated. Default is @code{0}.
10047 Set the video size. This option is for video only. For the syntax of this
10048 option, check the "Video size" section in the ffmpeg-utils manual. Default
10049 and minimum resolution is @code{640x480}.
10052 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
10053 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
10054 other integer value between this range is allowed.
10057 Set metadata injection. If set to @code{1}, the audio input will be segmented
10058 into 100ms output frames, each of them containing various loudness information
10059 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
10061 Default is @code{0}.
10064 Force the frame logging level.
10066 Available values are:
10069 information logging level
10071 verbose logging level
10074 By default, the logging level is set to @var{info}. If the @option{video} or
10075 the @option{metadata} options are set, it switches to @var{verbose}.
10080 Available modes can be cumulated (the option is a @code{flag} type). Possible
10084 Disable any peak mode (default).
10086 Enable sample-peak mode.
10088 Simple peak mode looking for the higher sample value. It logs a message
10089 for sample-peak (identified by @code{SPK}).
10091 Enable true-peak mode.
10093 If enabled, the peak lookup is done on an over-sampled version of the input
10094 stream for better peak accuracy. It logs a message for true-peak.
10095 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
10096 This mode requires a build with @code{libswresample}.
10101 @subsection Examples
10105 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
10107 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
10111 Run an analysis with @command{ffmpeg}:
10113 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
10117 @section interleave, ainterleave
10119 Temporally interleave frames from several inputs.
10121 @code{interleave} works with video inputs, @code{ainterleave} with audio.
10123 These filters read frames from several inputs and send the oldest
10124 queued frame to the output.
10126 Input streams must have a well defined, monotonically increasing frame
10129 In order to submit one frame to output, these filters need to enqueue
10130 at least one frame for each input, so they cannot work in case one
10131 input is not yet terminated and will not receive incoming frames.
10133 For example consider the case when one input is a @code{select} filter
10134 which always drop input frames. The @code{interleave} filter will keep
10135 reading from that input, but it will never be able to send new frames
10136 to output until the input will send an end-of-stream signal.
10138 Also, depending on inputs synchronization, the filters will drop
10139 frames in case one input receives more frames than the other ones, and
10140 the queue is already filled.
10142 These filters accept the following options:
10146 Set the number of different inputs, it is 2 by default.
10149 @subsection Examples
10153 Interleave frames belonging to different streams using @command{ffmpeg}:
10155 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
10159 Add flickering blur effect:
10161 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
10165 @section perms, aperms
10167 Set read/write permissions for the output frames.
10169 These filters are mainly aimed at developers to test direct path in the
10170 following filter in the filtergraph.
10172 The filters accept the following options:
10176 Select the permissions mode.
10178 It accepts the following values:
10181 Do nothing. This is the default.
10183 Set all the output frames read-only.
10185 Set all the output frames directly writable.
10187 Make the frame read-only if writable, and writable if read-only.
10189 Set each output frame read-only or writable randomly.
10193 Set the seed for the @var{random} mode, must be an integer included between
10194 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
10195 @code{-1}, the filter will try to use a good random seed on a best effort
10199 Note: in case of auto-inserted filter between the permission filter and the
10200 following one, the permission might not be received as expected in that
10201 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
10202 perms/aperms filter can avoid this problem.
10204 @section select, aselect
10206 Select frames to pass in output.
10208 This filter accepts the following options:
10213 Set expression, which is evaluated for each input frame.
10215 If the expression is evaluated to zero, the frame is discarded.
10217 If the evaluation result is negative or NaN, the frame is sent to the
10218 first output; otherwise it is sent to the output with index
10219 @code{ceil(val)-1}, assuming that the input index starts from 0.
10221 For example a value of @code{1.2} corresponds to the output with index
10222 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
10225 Set the number of outputs. The output to which to send the selected
10226 frame is based on the result of the evaluation. Default value is 1.
10229 The expression can contain the following constants:
10233 The (sequential) number of the filtered frame, starting from 0.
10236 The (sequential) number of the selected frame, starting from 0.
10238 @item prev_selected_n
10239 The sequential number of the last selected frame. It's NAN if undefined.
10242 The timebase of the input timestamps.
10245 The PTS (Presentation TimeStamp) of the filtered video frame,
10246 expressed in @var{TB} units. It's NAN if undefined.
10249 The PTS of the filtered video frame,
10250 expressed in seconds. It's NAN if undefined.
10253 The PTS of the previously filtered video frame. It's NAN if undefined.
10255 @item prev_selected_pts
10256 The PTS of the last previously filtered video frame. It's NAN if undefined.
10258 @item prev_selected_t
10259 The PTS of the last previously selected video frame. It's NAN if undefined.
10262 The PTS of the first video frame in the video. It's NAN if undefined.
10265 The time of the first video frame in the video. It's NAN if undefined.
10267 @item pict_type @emph{(video only)}
10268 The type of the filtered frame. It can assume one of the following
10280 @item interlace_type @emph{(video only)}
10281 The frame interlace type. It can assume one of the following values:
10284 The frame is progressive (not interlaced).
10286 The frame is top-field-first.
10288 The frame is bottom-field-first.
10291 @item consumed_sample_n @emph{(audio only)}
10292 the number of selected samples before the current frame
10294 @item samples_n @emph{(audio only)}
10295 the number of samples in the current frame
10297 @item sample_rate @emph{(audio only)}
10298 the input sample rate
10301 This is 1 if the filtered frame is a key-frame, 0 otherwise.
10304 the position in the file of the filtered frame, -1 if the information
10305 is not available (e.g. for synthetic video)
10307 @item scene @emph{(video only)}
10308 value between 0 and 1 to indicate a new scene; a low value reflects a low
10309 probability for the current frame to introduce a new scene, while a higher
10310 value means the current frame is more likely to be one (see the example below)
10314 The default value of the select expression is "1".
10316 @subsection Examples
10320 Select all frames in input:
10325 The example above is the same as:
10337 Select only I-frames:
10339 select='eq(pict_type\,I)'
10343 Select one frame every 100:
10345 select='not(mod(n\,100))'
10349 Select only frames contained in the 10-20 time interval:
10351 select=between(t\,10\,20)
10355 Select only I frames contained in the 10-20 time interval:
10357 select=between(t\,10\,20)*eq(pict_type\,I)
10361 Select frames with a minimum distance of 10 seconds:
10363 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
10367 Use aselect to select only audio frames with samples number > 100:
10369 aselect='gt(samples_n\,100)'
10373 Create a mosaic of the first scenes:
10375 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
10378 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
10382 Send even and odd frames to separate outputs, and compose them:
10384 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
10388 @section sendcmd, asendcmd
10390 Send commands to filters in the filtergraph.
10392 These filters read commands to be sent to other filters in the
10395 @code{sendcmd} must be inserted between two video filters,
10396 @code{asendcmd} must be inserted between two audio filters, but apart
10397 from that they act the same way.
10399 The specification of commands can be provided in the filter arguments
10400 with the @var{commands} option, or in a file specified by the
10401 @var{filename} option.
10403 These filters accept the following options:
10406 Set the commands to be read and sent to the other filters.
10408 Set the filename of the commands to be read and sent to the other
10412 @subsection Commands syntax
10414 A commands description consists of a sequence of interval
10415 specifications, comprising a list of commands to be executed when a
10416 particular event related to that interval occurs. The occurring event
10417 is typically the current frame time entering or leaving a given time
10420 An interval is specified by the following syntax:
10422 @var{START}[-@var{END}] @var{COMMANDS};
10425 The time interval is specified by the @var{START} and @var{END} times.
10426 @var{END} is optional and defaults to the maximum time.
10428 The current frame time is considered within the specified interval if
10429 it is included in the interval [@var{START}, @var{END}), that is when
10430 the time is greater or equal to @var{START} and is lesser than
10433 @var{COMMANDS} consists of a sequence of one or more command
10434 specifications, separated by ",", relating to that interval. The
10435 syntax of a command specification is given by:
10437 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
10440 @var{FLAGS} is optional and specifies the type of events relating to
10441 the time interval which enable sending the specified command, and must
10442 be a non-null sequence of identifier flags separated by "+" or "|" and
10443 enclosed between "[" and "]".
10445 The following flags are recognized:
10448 The command is sent when the current frame timestamp enters the
10449 specified interval. In other words, the command is sent when the
10450 previous frame timestamp was not in the given interval, and the
10454 The command is sent when the current frame timestamp leaves the
10455 specified interval. In other words, the command is sent when the
10456 previous frame timestamp was in the given interval, and the
10460 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
10463 @var{TARGET} specifies the target of the command, usually the name of
10464 the filter class or a specific filter instance name.
10466 @var{COMMAND} specifies the name of the command for the target filter.
10468 @var{ARG} is optional and specifies the optional list of argument for
10469 the given @var{COMMAND}.
10471 Between one interval specification and another, whitespaces, or
10472 sequences of characters starting with @code{#} until the end of line,
10473 are ignored and can be used to annotate comments.
10475 A simplified BNF description of the commands specification syntax
10478 @var{COMMAND_FLAG} ::= "enter" | "leave"
10479 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
10480 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
10481 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
10482 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
10483 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
10486 @subsection Examples
10490 Specify audio tempo change at second 4:
10492 asendcmd=c='4.0 atempo tempo 1.5',atempo
10496 Specify a list of drawtext and hue commands in a file.
10498 # show text in the interval 5-10
10499 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
10500 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
10502 # desaturate the image in the interval 15-20
10503 15.0-20.0 [enter] hue s 0,
10504 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
10506 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
10508 # apply an exponential saturation fade-out effect, starting from time 25
10509 25 [enter] hue s exp(25-t)
10512 A filtergraph allowing to read and process the above command list
10513 stored in a file @file{test.cmd}, can be specified with:
10515 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
10520 @section setpts, asetpts
10522 Change the PTS (presentation timestamp) of the input frames.
10524 @code{setpts} works on video frames, @code{asetpts} on audio frames.
10526 This filter accepts the following options:
10531 The expression which is evaluated for each frame to construct its timestamp.
10535 The expression is evaluated through the eval API and can contain the following
10540 frame rate, only defined for constant frame-rate video
10543 The presentation timestamp in input
10546 The count of the input frame for video or the number of consumed samples,
10547 not including the current frame for audio, starting from 0.
10549 @item NB_CONSUMED_SAMPLES
10550 The number of consumed samples, not including the current frame (only
10553 @item NB_SAMPLES, S
10554 The number of samples in the current frame (only audio)
10556 @item SAMPLE_RATE, SR
10557 The audio sample rate.
10560 The PTS of the first frame.
10563 the time in seconds of the first frame
10566 State whether the current frame is interlaced.
10569 the time in seconds of the current frame
10572 original position in the file of the frame, or undefined if undefined
10573 for the current frame
10576 The previous input PTS.
10579 previous input time in seconds
10582 The previous output PTS.
10585 previous output time in seconds
10588 The wallclock (RTC) time in microseconds.. This is deprecated, use time(0)
10592 The wallclock (RTC) time at the start of the movie in microseconds.
10595 The timebase of the input timestamps.
10599 @subsection Examples
10603 Start counting PTS from zero
10605 setpts=PTS-STARTPTS
10609 Apply fast motion effect:
10615 Apply slow motion effect:
10621 Set fixed rate of 25 frames per second:
10627 Set fixed rate 25 fps with some jitter:
10629 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
10633 Apply an offset of 10 seconds to the input PTS:
10639 Generate timestamps from a "live source" and rebase onto the current timebase:
10641 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
10645 Generate timestamps by counting samples:
10652 @section settb, asettb
10654 Set the timebase to use for the output frames timestamps.
10655 It is mainly useful for testing timebase configuration.
10657 It accepts the following parameters:
10662 The expression which is evaluated into the output timebase.
10666 The value for @option{tb} is an arithmetic expression representing a
10667 rational. The expression can contain the constants "AVTB" (the default
10668 timebase), "intb" (the input timebase) and "sr" (the sample rate,
10669 audio only). Default value is "intb".
10671 @subsection Examples
10675 Set the timebase to 1/25:
10681 Set the timebase to 1/10:
10687 Set the timebase to 1001/1000:
10693 Set the timebase to 2*intb:
10699 Set the default timebase value:
10706 Convert input audio to a video output representing
10707 frequency spectrum logarithmically (using constant Q transform with
10708 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
10710 The filter accepts the following options:
10714 Specify transform volume (multiplier) expression. The expression can contain
10717 @item frequency, freq, f
10718 the frequency where transform is evaluated
10719 @item timeclamp, tc
10720 value of timeclamp option
10724 @item a_weighting(f)
10725 A-weighting of equal loudness
10726 @item b_weighting(f)
10727 B-weighting of equal loudness
10728 @item c_weighting(f)
10729 C-weighting of equal loudness
10731 Default value is @code{16}.
10734 Specify transform length expression. The expression can contain variables:
10736 @item frequency, freq, f
10737 the frequency where transform is evaluated
10738 @item timeclamp, tc
10739 value of timeclamp option
10741 Default value is @code{384/f*tc/(384/f+tc)}.
10744 Specify the transform timeclamp. At low frequency, there is trade-off between
10745 accuracy in time domain and frequency domain. If timeclamp is lower,
10746 event in time domain is represented more accurately (such as fast bass drum),
10747 otherwise event in frequency domain is represented more accurately
10748 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
10751 Specify the transform coeffclamp. If coeffclamp is lower, transform is
10752 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
10753 Default value is @code{1.0}.
10756 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
10757 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
10758 Default value is @code{3.0}.
10761 Specify font file for use with freetype. If not specified, use embedded font.
10764 Specify font color expression. This is arithmetic expression that should return
10765 integer value 0xRRGGBB. The expression can contain variables:
10767 @item frequency, freq, f
10768 the frequency where transform is evaluated
10769 @item timeclamp, tc
10770 value of timeclamp option
10775 midi number of frequency f, some midi numbers: E0(16), C1(24), C2(36), A4(69)
10776 @item r(x), g(x), b(x)
10777 red, green, and blue value of intensity x
10779 Default value is @code{st(0, (midi(f)-59.5)/12);
10780 st(1, if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));
10781 r(1-ld(1)) + b(ld(1))}
10784 If set to 1 (the default), the video size is 1920x1080 (full HD),
10785 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
10788 Specify video fps. Default value is @code{25}.
10791 Specify number of transform per frame, so there are fps*count transforms
10792 per second. Note that audio data rate must be divisible by fps*count.
10793 Default value is @code{6}.
10797 @subsection Examples
10801 Playing audio while showing the spectrum:
10803 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
10807 Same as above, but with frame rate 30 fps:
10809 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
10813 Playing at 960x540 and lower CPU usage:
10815 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
10819 A1 and its harmonics: A1, A2, (near)E3, A3:
10821 ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
10822 asplit[a][out1]; [a] showcqt [out0]'
10826 Same as above, but with more accuracy in frequency domain (and slower):
10828 ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
10829 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
10833 B-weighting of equal loudness
10835 volume=16*b_weighting(f)
10841 tlength=100/f*tc/(100/f+tc)
10845 Custom fontcolor, C-note is colored green, others are colored blue
10847 fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))'
10852 @section showspectrum
10854 Convert input audio to a video output, representing the audio frequency
10857 The filter accepts the following options:
10861 Specify the video size for the output. For the syntax of this option, check
10862 the "Video size" section in the ffmpeg-utils manual. Default value is
10866 Specify how the spectrum should slide along the window.
10868 It accepts the following values:
10871 the samples start again on the left when they reach the right
10873 the samples scroll from right to left
10875 frames are only produced when the samples reach the right
10878 Default value is @code{replace}.
10881 Specify display mode.
10883 It accepts the following values:
10886 all channels are displayed in the same row
10888 all channels are displayed in separate rows
10891 Default value is @samp{combined}.
10894 Specify display color mode.
10896 It accepts the following values:
10899 each channel is displayed in a separate color
10901 each channel is is displayed using the same color scheme
10904 Default value is @samp{channel}.
10907 Specify scale used for calculating intensity color values.
10909 It accepts the following values:
10914 square root, default
10921 Default value is @samp{sqrt}.
10924 Set saturation modifier for displayed colors. Negative values provide
10925 alternative color scheme. @code{0} is no saturation at all.
10926 Saturation must be in [-10.0, 10.0] range.
10927 Default value is @code{1}.
10930 Set window function.
10932 It accepts the following values:
10935 No samples pre-processing (do not expect this to be faster)
10944 Default value is @code{hann}.
10947 The usage is very similar to the showwaves filter; see the examples in that
10950 @subsection Examples
10954 Large window with logarithmic color scaling:
10956 showspectrum=s=1280x480:scale=log
10960 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
10962 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10963 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
10969 Convert input audio to a video output, representing the samples waves.
10971 The filter accepts the following options:
10975 Specify the video size for the output. For the syntax of this option, check
10976 the "Video size" section in the ffmpeg-utils manual. Default value
10982 Available values are:
10985 Draw a point for each sample.
10988 Draw a vertical line for each sample.
10991 Draw a point for each sample and a line between them.
10994 Draw a centered vertical line for each sample.
10997 Default value is @code{point}.
11000 Set the number of samples which are printed on the same column. A
11001 larger value will decrease the frame rate. Must be a positive
11002 integer. This option can be set only if the value for @var{rate}
11003 is not explicitly specified.
11006 Set the (approximate) output frame rate. This is done by setting the
11007 option @var{n}. Default value is "25".
11009 @item split_channels
11010 Set if channels should be drawn separately or overlap. Default value is 0.
11014 @subsection Examples
11018 Output the input file audio and the corresponding video representation
11021 amovie=a.mp3,asplit[out0],showwaves[out1]
11025 Create a synthetic signal and show it with showwaves, forcing a
11026 frame rate of 30 frames per second:
11028 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
11032 @section split, asplit
11034 Split input into several identical outputs.
11036 @code{asplit} works with audio input, @code{split} with video.
11038 The filter accepts a single parameter which specifies the number of outputs. If
11039 unspecified, it defaults to 2.
11041 @subsection Examples
11045 Create two separate outputs from the same input:
11047 [in] split [out0][out1]
11051 To create 3 or more outputs, you need to specify the number of
11054 [in] asplit=3 [out0][out1][out2]
11058 Create two separate outputs from the same input, one cropped and
11061 [in] split [splitout1][splitout2];
11062 [splitout1] crop=100:100:0:0 [cropout];
11063 [splitout2] pad=200:200:100:100 [padout];
11067 Create 5 copies of the input audio with @command{ffmpeg}:
11069 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
11075 Receive commands sent through a libzmq client, and forward them to
11076 filters in the filtergraph.
11078 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
11079 must be inserted between two video filters, @code{azmq} between two
11082 To enable these filters you need to install the libzmq library and
11083 headers and configure FFmpeg with @code{--enable-libzmq}.
11085 For more information about libzmq see:
11086 @url{http://www.zeromq.org/}
11088 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
11089 receives messages sent through a network interface defined by the
11090 @option{bind_address} option.
11092 The received message must be in the form:
11094 @var{TARGET} @var{COMMAND} [@var{ARG}]
11097 @var{TARGET} specifies the target of the command, usually the name of
11098 the filter class or a specific filter instance name.
11100 @var{COMMAND} specifies the name of the command for the target filter.
11102 @var{ARG} is optional and specifies the optional argument list for the
11103 given @var{COMMAND}.
11105 Upon reception, the message is processed and the corresponding command
11106 is injected into the filtergraph. Depending on the result, the filter
11107 will send a reply to the client, adopting the format:
11109 @var{ERROR_CODE} @var{ERROR_REASON}
11113 @var{MESSAGE} is optional.
11115 @subsection Examples
11117 Look at @file{tools/zmqsend} for an example of a zmq client which can
11118 be used to send commands processed by these filters.
11120 Consider the following filtergraph generated by @command{ffplay}
11122 ffplay -dumpgraph 1 -f lavfi "
11123 color=s=100x100:c=red [l];
11124 color=s=100x100:c=blue [r];
11125 nullsrc=s=200x100, zmq [bg];
11126 [bg][l] overlay [bg+l];
11127 [bg+l][r] overlay=x=100 "
11130 To change the color of the left side of the video, the following
11131 command can be used:
11133 echo Parsed_color_0 c yellow | tools/zmqsend
11136 To change the right side:
11138 echo Parsed_color_1 c pink | tools/zmqsend
11141 @c man end MULTIMEDIA FILTERS
11143 @chapter Multimedia Sources
11144 @c man begin MULTIMEDIA SOURCES
11146 Below is a description of the currently available multimedia sources.
11150 This is the same as @ref{movie} source, except it selects an audio
11156 Read audio and/or video stream(s) from a movie container.
11158 It accepts the following parameters:
11162 The name of the resource to read (not necessarily a file; it can also be a
11163 device or a stream accessed through some protocol).
11165 @item format_name, f
11166 Specifies the format assumed for the movie to read, and can be either
11167 the name of a container or an input device. If not specified, the
11168 format is guessed from @var{movie_name} or by probing.
11170 @item seek_point, sp
11171 Specifies the seek point in seconds. The frames will be output
11172 starting from this seek point. The parameter is evaluated with
11173 @code{av_strtod}, so the numerical value may be suffixed by an IS
11174 postfix. The default value is "0".
11177 Specifies the streams to read. Several streams can be specified,
11178 separated by "+". The source will then have as many outputs, in the
11179 same order. The syntax is explained in the ``Stream specifiers''
11180 section in the ffmpeg manual. Two special names, "dv" and "da" specify
11181 respectively the default (best suited) video and audio stream. Default
11182 is "dv", or "da" if the filter is called as "amovie".
11184 @item stream_index, si
11185 Specifies the index of the video stream to read. If the value is -1,
11186 the most suitable video stream will be automatically selected. The default
11187 value is "-1". Deprecated. If the filter is called "amovie", it will select
11188 audio instead of video.
11191 Specifies how many times to read the stream in sequence.
11192 If the value is less than 1, the stream will be read again and again.
11193 Default value is "1".
11195 Note that when the movie is looped the source timestamps are not
11196 changed, so it will generate non monotonically increasing timestamps.
11199 It allows overlaying a second video on top of the main input of
11200 a filtergraph, as shown in this graph:
11202 input -----------> deltapts0 --> overlay --> output
11205 movie --> scale--> deltapts1 -------+
11207 @subsection Examples
11211 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
11212 on top of the input labelled "in":
11214 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
11215 [in] setpts=PTS-STARTPTS [main];
11216 [main][over] overlay=16:16 [out]
11220 Read from a video4linux2 device, and overlay it on top of the input
11223 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
11224 [in] setpts=PTS-STARTPTS [main];
11225 [main][over] overlay=16:16 [out]
11229 Read the first video stream and the audio stream with id 0x81 from
11230 dvd.vob; the video is connected to the pad named "video" and the audio is
11231 connected to the pad named "audio":
11233 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
11237 @c man end MULTIMEDIA SOURCES