1 @chapter Filtering Introduction
2 @c man begin FILTERING INTRODUCTION
4 Filtering in FFmpeg is enabled through the libavfilter library.
6 In libavfilter, a filter can have multiple inputs and multiple
8 To illustrate the sorts of things that are possible, we consider the
13 input --> split ---------------------> overlay --> output
16 +-----> crop --> vflip -------+
19 This filtergraph splits the input stream in two streams, sends one
20 stream through the crop filter and the vflip filter before merging it
21 back with the other stream by overlaying it on top. You can use the
22 following command to achieve this:
25 ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
28 The result will be that in output the top half of the video is mirrored
31 Filters in the same linear chain are separated by commas, and distinct
32 linear chains of filters are separated by semicolons. In our example,
33 @var{crop,vflip} are in one linear chain, @var{split} and
34 @var{overlay} are separately in another. The points where the linear
35 chains join are labelled by names enclosed in square brackets. In the
36 example, the split filter generates two outputs that are associated to
37 the labels @var{[main]} and @var{[tmp]}.
39 The stream sent to the second output of @var{split}, labelled as
40 @var{[tmp]}, is processed through the @var{crop} filter, which crops
41 away the lower half part of the video, and then vertically flipped. The
42 @var{overlay} filter takes in input the first unchanged output of the
43 split filter (which was labelled as @var{[main]}), and overlay on its
44 lower half the output generated by the @var{crop,vflip} filterchain.
46 Some filters take in input a list of parameters: they are specified
47 after the filter name and an equal sign, and are separated from each other
50 There exist so-called @var{source filters} that do not have an
51 audio/video input, and @var{sink filters} that will not have audio/video
54 @c man end FILTERING INTRODUCTION
57 @c man begin GRAPH2DOT
59 The @file{graph2dot} program included in the FFmpeg @file{tools}
60 directory can be used to parse a filtergraph description and issue a
61 corresponding textual representation in the dot language.
68 to see how to use @file{graph2dot}.
70 You can then pass the dot description to the @file{dot} program (from
71 the graphviz suite of programs) and obtain a graphical representation
74 For example the sequence of commands:
76 echo @var{GRAPH_DESCRIPTION} | \
77 tools/graph2dot -o graph.tmp && \
78 dot -Tpng graph.tmp -o graph.png && \
82 can be used to create and display an image representing the graph
83 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
84 a complete self-contained graph, with its inputs and outputs explicitly defined.
85 For example if your command line is of the form:
87 ffmpeg -i infile -vf scale=640:360 outfile
89 your @var{GRAPH_DESCRIPTION} string will need to be of the form:
91 nullsrc,scale=640:360,nullsink
93 you may also need to set the @var{nullsrc} parameters and add a @var{format}
94 filter in order to simulate a specific input file.
98 @chapter Filtergraph description
99 @c man begin FILTERGRAPH DESCRIPTION
101 A filtergraph is a directed graph of connected filters. It can contain
102 cycles, and there can be multiple links between a pair of
103 filters. Each link has one input pad on one side connecting it to one
104 filter from which it takes its input, and one output pad on the other
105 side connecting it to the one filter accepting its output.
107 Each filter in a filtergraph is an instance of a filter class
108 registered in the application, which defines the features and the
109 number of input and output pads of the filter.
111 A filter with no input pads is called a "source", a filter with no
112 output pads is called a "sink".
114 @anchor{Filtergraph syntax}
115 @section Filtergraph syntax
117 A filtergraph can be represented using a textual representation, which is
118 recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
119 options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the
120 @code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} function defined in
121 @file{libavfilter/avfilter.h}.
123 A filterchain consists of a sequence of connected filters, each one
124 connected to the previous one in the sequence. A filterchain is
125 represented by a list of ","-separated filter descriptions.
127 A filtergraph consists of a sequence of filterchains. A sequence of
128 filterchains is represented by a list of ";"-separated filterchain
131 A filter is represented by a string of the form:
132 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
134 @var{filter_name} is the name of the filter class of which the
135 described filter is an instance of, and has to be the name of one of
136 the filter classes registered in the program.
137 The name of the filter class is optionally followed by a string
140 @var{arguments} is a string which contains the parameters used to
141 initialize the filter instance. It may have one of the following forms:
145 A ':'-separated list of @var{key=value} pairs.
148 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
149 the option names in the order they are declared. E.g. the @code{fade} filter
150 declares three options in this order -- @option{type}, @option{start_frame} and
151 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
152 @var{in} is assigned to the option @option{type}, @var{0} to
153 @option{start_frame} and @var{30} to @option{nb_frames}.
156 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
157 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
158 follow the same constraints order of the previous point. The following
159 @var{key=value} pairs can be set in any preferred order.
163 If the option value itself is a list of items (e.g. the @code{format} filter
164 takes a list of pixel formats), the items in the list are usually separated by
167 The list of arguments can be quoted using the character "'" as initial
168 and ending mark, and the character '\' for escaping the characters
169 within the quoted text; otherwise the argument string is considered
170 terminated when the next special character (belonging to the set
171 "[]=;,") is encountered.
173 The name and arguments of the filter are optionally preceded and
174 followed by a list of link labels.
175 A link label allows 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 Follows a BNF description for the filtergraph syntax:
209 @var{NAME} ::= sequence of alphanumeric characters and '_'
210 @var{LINKLABEL} ::= "[" @var{NAME} "]"
211 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
212 @var{FILTER_ARGUMENTS} ::= sequence of chars (eventually quoted)
213 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
214 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
215 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
218 @section Notes on filtergraph escaping
220 Filtergraph description composition entails several levels of
221 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
222 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
223 information about the employed escaping procedure.
225 A first level escaping affects the content of each filter option
226 value, which may contain the special character @code{:} used to
227 separate values, or one of the escaping characters @code{\'}.
229 A second level escaping affects the whole filter description, which
230 may contain the escaping characters @code{\'} or the special
231 characters @code{[],;} used by the filtergraph description.
233 Finally, when you specify a filtergraph on a shell commandline, you
234 need to perform a third level escaping for the shell special
235 characters contained within it.
237 For example, consider the following string to be embedded in
238 the @ref{drawtext} filter description @option{text} value:
240 this is a 'string': may contain one, or more, special characters
243 This string contains the @code{'} special escaping character, and the
244 @code{:} special character, so it needs to be escaped in this way:
246 text=this is a \'string\'\: may contain one, or more, special characters
249 A second level of escaping is required when embedding the filter
250 description in a filtergraph description, in order to escape all the
251 filtergraph special characters. Thus the example above becomes:
253 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
255 (note that in addition to the @code{\'} escaping special characters,
256 also @code{,} needs to be escaped).
258 Finally an additional level of escaping is needed when writing the
259 filtergraph description in a shell command, which depends on the
260 escaping rules of the adopted shell. For example, assuming that
261 @code{\} is special and needs to be escaped with another @code{\}, the
262 previous string will finally result in:
264 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
267 @chapter Timeline editing
269 Some filters support a generic @option{enable} option. For the filters
270 supporting timeline editing, this option can be set to an expression which is
271 evaluated before sending a frame to the filter. If the evaluation is non-zero,
272 the filter will be enabled, otherwise the frame will be sent unchanged to the
273 next filter in the filtergraph.
275 The expression accepts the following values:
278 timestamp expressed in seconds, NAN if the input timestamp is unknown
281 sequential number of the input frame, starting from 0
284 the position in the file of the input frame, NAN if unknown
287 Additionally, these filters support an @option{enable} command that can be used
288 to re-define the expression.
290 Like any other filtering option, the @option{enable} option follows the same
293 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
294 minutes, and a @ref{curves} filter starting at 3 seconds:
296 smartblur = enable='between(t,10,3*60)',
297 curves = enable='gte(t,3)' : preset=cross_process
300 @c man end FILTERGRAPH DESCRIPTION
302 @chapter Audio Filters
303 @c man begin AUDIO FILTERS
305 When you configure your FFmpeg build, you can disable any of the
306 existing filters using @code{--disable-filters}.
307 The configure output will show the audio filters included in your
310 Below is a description of the currently available audio filters.
314 Convert the input audio format to the specified formats.
316 @emph{This filter is deprecated. Use @ref{aformat} instead.}
318 The filter accepts a string of the form:
319 "@var{sample_format}:@var{channel_layout}".
321 @var{sample_format} specifies the sample format, and can be a string or the
322 corresponding numeric value defined in @file{libavutil/samplefmt.h}. Use 'p'
323 suffix for a planar sample format.
325 @var{channel_layout} specifies the channel layout, and can be a string
326 or the corresponding number value defined in @file{libavutil/channel_layout.h}.
328 The special parameter "auto", signifies that the filter will
329 automatically select the output format depending on the output filter.
335 Convert input to float, planar, stereo:
341 Convert input to unsigned 8-bit, automatically select out channel layout:
349 Delay one or more audio channels.
351 Samples in delayed channel are filled with silence.
353 The filter accepts the following option:
357 Set list of delays in milliseconds for each channel separated by '|'.
358 At least one delay greater than 0 should be provided.
359 Unused delays will be silently ignored. If number of given delays is
360 smaller than number of channels all remaining channels will not be delayed.
367 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
368 the second channel (and any other channels that may be present) unchanged.
376 Apply echoing to the input audio.
378 Echoes are reflected sound and can occur naturally amongst mountains
379 (and sometimes large buildings) when talking or shouting; digital echo
380 effects emulate this behaviour and are often used to help fill out the
381 sound of a single instrument or vocal. The time difference between the
382 original signal and the reflection is the @code{delay}, and the
383 loudness of the reflected signal is the @code{decay}.
384 Multiple echoes can have different delays and decays.
386 A description of the accepted parameters follows.
390 Set input gain of reflected signal. Default is @code{0.6}.
393 Set output gain of reflected signal. Default is @code{0.3}.
396 Set list of time intervals in milliseconds between original signal and reflections
397 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
398 Default is @code{1000}.
401 Set list of loudnesses of reflected signals separated by '|'.
402 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
403 Default is @code{0.5}.
410 Make it sound as if there are twice as many instruments as are actually playing:
412 aecho=0.8:0.88:60:0.4
416 If delay is very short, then it sound like a (metallic) robot playing music:
422 A longer delay will sound like an open air concert in the mountains:
424 aecho=0.8:0.9:1000:0.3
428 Same as above but with one more mountain:
430 aecho=0.8:0.9:1000|1800:0.3|0.25
436 Modify an audio signal according to the specified expressions.
438 This filter accepts one or more expressions (one for each channel),
439 which are evaluated and used to modify a corresponding audio signal.
441 This filter accepts the following options:
445 Set the '|'-separated expressions list for each separate channel. If
446 the number of input channels is greater than the number of
447 expressions, the last specified expression is used for the remaining
450 @item channel_layout, c
451 Set output channel layout. If not specified, the channel layout is
452 specified by the number of expressions. If set to @samp{same}, it will
453 use by default the same input channel layout.
456 Each expression in @var{exprs} can contain the following constants and functions:
460 channel number of the current expression
463 number of the evaluated sample, starting from 0
469 time of the evaluated sample expressed in seconds
472 @item nb_out_channels
473 input and output number of channels
476 the value of input channel with number @var{CH}
479 Note: this filter is slow. For faster processing you should use a
488 aeval=val(ch)/2:c=same
492 Invert phase of the second channel:
500 Apply fade-in/out effect to input audio.
502 A description of the accepted parameters follows.
506 Specify the effect type, can be either @code{in} for fade-in, or
507 @code{out} for a fade-out effect. Default is @code{in}.
509 @item start_sample, ss
510 Specify the number of the start sample for starting to apply the fade
511 effect. Default is 0.
514 Specify the number of samples for which the fade effect has to last. At
515 the end of the fade-in effect the output audio will have the same
516 volume as the input audio, at the end of the fade-out transition
517 the output audio will be silence. Default is 44100.
520 Specify time for starting to apply the fade effect. Default is 0.
521 The accepted syntax is:
523 [-]HH[:MM[:SS[.m...]]]
526 See also the function @code{av_parse_time()}.
527 If set this option is used instead of @var{start_sample} one.
530 Specify the duration for which the fade effect has to last. Default is 0.
531 The accepted syntax is:
533 [-]HH[:MM[:SS[.m...]]]
536 See also the function @code{av_parse_time()}.
537 At the end of the fade-in effect the output audio will have the same
538 volume as the input audio, at the end of the fade-out transition
539 the output audio will be silence.
540 If set this option is used instead of @var{nb_samples} one.
543 Set curve for fade transition.
545 It accepts the following values:
548 select triangular, linear slope (default)
550 select quarter of sine wave
552 select half of sine wave
554 select exponential sine wave
558 select inverted parabola
574 Fade in first 15 seconds of audio:
580 Fade out last 25 seconds of a 900 seconds audio:
582 afade=t=out:st=875:d=25
589 Set output format constraints for the input audio. The framework will
590 negotiate the most appropriate format to minimize conversions.
592 The filter accepts the following named parameters:
596 A '|'-separated list of requested sample formats.
599 A '|'-separated list of requested sample rates.
601 @item channel_layouts
602 A '|'-separated list of requested channel layouts.
604 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
605 for the required syntax.
608 If a parameter is omitted, all values are allowed.
610 For example to force the output to either unsigned 8-bit or signed 16-bit stereo:
612 aformat=sample_fmts=u8|s16:channel_layouts=stereo
617 Apply a two-pole all-pass filter with central frequency (in Hz)
618 @var{frequency}, and filter-width @var{width}.
619 An all-pass filter changes the audio's frequency to phase relationship
620 without changing its frequency to amplitude relationship.
622 The filter accepts the following options:
629 Set method to specify band-width of filter.
642 Specify the band-width of a filter in width_type units.
647 Merge two or more audio streams into a single multi-channel stream.
649 The filter accepts the following options:
654 Set the number of inputs. Default is 2.
658 If the channel layouts of the inputs are disjoint, and therefore compatible,
659 the channel layout of the output will be set accordingly and the channels
660 will be reordered as necessary. If the channel layouts of the inputs are not
661 disjoint, the output will have all the channels of the first input then all
662 the channels of the second input, in that order, and the channel layout of
663 the output will be the default value corresponding to the total number of
666 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
667 is FC+BL+BR, then the output will be in 5.1, with the channels in the
668 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
669 first input, b1 is the first channel of the second input).
671 On the other hand, if both input are in stereo, the output channels will be
672 in the default order: a1, a2, b1, b2, and the channel layout will be
673 arbitrarily set to 4.0, which may or may not be the expected value.
675 All inputs must have the same sample rate, and format.
677 If inputs do not have the same duration, the output will stop with the
684 Merge two mono files into a stereo stream:
686 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
690 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
692 ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv
698 Mixes multiple audio inputs into a single output.
702 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
704 will mix 3 input audio streams to a single output with the same duration as the
705 first input and a dropout transition time of 3 seconds.
707 The filter accepts the following named parameters:
711 Number of inputs. If unspecified, it defaults to 2.
714 How to determine the end-of-stream.
718 Duration of longest input. (default)
721 Duration of shortest input.
724 Duration of first input.
728 @item dropout_transition
729 Transition time, in seconds, for volume renormalization when an input
730 stream ends. The default value is 2 seconds.
736 Pass the audio source unchanged to the output.
740 Pad the end of a audio stream with silence, this can be used together with
741 -shortest to extend audio streams to the same length as the video stream.
744 Add a phasing effect to the input audio.
746 A phaser filter creates series of peaks and troughs in the frequency spectrum.
747 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
749 A description of the accepted parameters follows.
753 Set input gain. Default is 0.4.
756 Set output gain. Default is 0.74
759 Set delay in milliseconds. Default is 3.0.
762 Set decay. Default is 0.4.
765 Set modulation speed in Hz. Default is 0.5.
768 Set modulation type. Default is triangular.
770 It accepts the following values:
780 Resample the input audio to the specified parameters, using the
781 libswresample library. If none are specified then the filter will
782 automatically convert between its input and output.
784 This filter is also able to stretch/squeeze the audio data to make it match
785 the timestamps or to inject silence / cut out audio to make it match the
786 timestamps, do a combination of both or do neither.
788 The filter accepts the syntax
789 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
790 expresses a sample rate and @var{resampler_options} is a list of
791 @var{key}=@var{value} pairs, separated by ":". See the
792 ffmpeg-resampler manual for the complete list of supported options.
798 Resample the input audio to 44100Hz:
804 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
805 samples per second compensation:
811 @section asetnsamples
813 Set the number of samples per each output audio frame.
815 The last output packet may contain a different number of samples, as
816 the filter will flush all the remaining samples when the input audio
819 The filter accepts the following options:
823 @item nb_out_samples, n
824 Set the number of frames per each output audio frame. The number is
825 intended as the number of samples @emph{per each channel}.
826 Default value is 1024.
829 If set to 1, the filter will pad the last audio frame with zeroes, so
830 that the last frame will contain the same number of samples as the
831 previous ones. Default value is 1.
834 For example, to set the number of per-frame samples to 1234 and
835 disable padding for the last frame, use:
837 asetnsamples=n=1234:p=0
842 Set the sample rate without altering the PCM data.
843 This will result in a change of speed and pitch.
845 The filter accepts the following options:
849 Set the output sample rate. Default is 44100 Hz.
854 Show a line containing various information for each input audio frame.
855 The input audio is not modified.
857 The shown line contains a sequence of key/value pairs of the form
858 @var{key}:@var{value}.
860 A description of each shown parameter follows:
864 sequential number of the input frame, starting from 0
867 Presentation timestamp of the input frame, in time base units; the time base
868 depends on the filter input pad, and is usually 1/@var{sample_rate}.
871 presentation timestamp of the input frame in seconds
874 position of the frame in the input stream, -1 if this information in
875 unavailable and/or meaningless (for example in case of synthetic audio)
884 sample rate for the audio frame
887 number of samples (per channel) in the frame
890 Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio
891 the data is treated as if all the planes were concatenated.
893 @item plane_checksums
894 A list of Adler-32 checksums for each data plane.
899 Display time domain statistical information about the audio channels.
900 Statistics are calculated and displayed for each audio channel and,
901 where applicable, an overall figure is also given.
903 The filter accepts the following option:
906 Short window length in seconds, used for peak and trough RMS measurement.
907 Default is @code{0.05} (50 miliseconds). Allowed range is @code{[0.1 - 10]}.
910 A description of each shown parameter follows:
914 Mean amplitude displacement from zero.
917 Minimal sample level.
920 Maximal sample level.
924 Standard peak and RMS level measured in dBFS.
928 Peak and trough values for RMS level measured over a short window.
931 Standard ratio of peak to RMS level (note: not in dB).
934 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
935 (i.e. either @var{Min level} or @var{Max level}).
938 Number of occasions (not the number of samples) that the signal attained either
939 @var{Min level} or @var{Max level}.
944 Forward two audio streams and control the order the buffers are forwarded.
946 The filter accepts the following options:
950 Set the expression deciding which stream should be
951 forwarded next: if the result is negative, the first stream is forwarded; if
952 the result is positive or zero, the second stream is forwarded. It can use
953 the following variables:
957 number of buffers forwarded so far on each stream
959 number of samples forwarded so far on each stream
961 current timestamp of each stream
964 The default value is @code{t1-t2}, which means to always forward the stream
965 that has a smaller timestamp.
970 Stress-test @code{amerge} by randomly sending buffers on the wrong
971 input, while avoiding too much of a desynchronization:
973 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
974 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
980 Synchronize audio data with timestamps by squeezing/stretching it and/or
981 dropping samples/adding silence when needed.
983 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
985 The filter accepts the following named parameters:
989 Enable stretching/squeezing the data to make it match the timestamps. Disabled
990 by default. When disabled, time gaps are covered with silence.
993 Minimum difference between timestamps and audio data (in seconds) to trigger
994 adding/dropping samples. Default value is 0.1. If you get non-perfect sync with
995 this filter, try setting this parameter to 0.
998 Maximum compensation in samples per second. Relevant only with compensate=1.
1002 Assume the first pts should be this value. The time base is 1 / sample rate.
1003 This allows for padding/trimming at the start of stream. By default, no
1004 assumption is made about the first frame's expected pts, so no padding or
1005 trimming is done. For example, this could be set to 0 to pad the beginning with
1006 silence if an audio stream starts after the video stream or to trim any samples
1007 with a negative pts due to encoder delay.
1015 The filter accepts exactly one parameter, the audio tempo. If not
1016 specified then the filter will assume nominal 1.0 tempo. Tempo must
1017 be in the [0.5, 2.0] range.
1019 @subsection Examples
1023 Slow down audio to 80% tempo:
1029 To speed up audio to 125% tempo:
1037 Trim the input so that the output contains one continuous subpart of the input.
1039 This filter accepts the following options:
1042 Specify time of the start of the kept section, i.e. the audio sample
1043 with the timestamp @var{start} will be the first sample in the output.
1046 Specify time of the first audio sample that will be dropped, i.e. the
1047 audio sample immediately preceding the one with the timestamp @var{end} will be
1048 the last sample in the output.
1051 Same as @var{start}, except this option sets the start timestamp in samples
1055 Same as @var{end}, except this option sets the end timestamp in samples instead
1059 Specify maximum duration of the output.
1062 Number of the first sample that should be passed to output.
1065 Number of the first sample that should be dropped.
1068 @option{start}, @option{end}, @option{duration} are expressed as time
1069 duration specifications, check the "Time duration" section in the
1070 ffmpeg-utils manual.
1072 Note that the first two sets of the start/end options and the @option{duration}
1073 option look at the frame timestamp, while the _sample options simply count the
1074 samples that pass through the filter. So start/end_pts and start/end_sample will
1075 give different results when the timestamps are wrong, inexact or do not start at
1076 zero. Also note that this filter does not modify the timestamps. If you wish
1077 that the output timestamps start at zero, insert the asetpts filter after the
1080 If multiple start or end options are set, this filter tries to be greedy and
1081 keep all samples that match at least one of the specified constraints. To keep
1082 only the part that matches all the constraints at once, chain multiple atrim
1085 The defaults are such that all the input is kept. So it is possible to set e.g.
1086 just the end values to keep everything before the specified time.
1091 drop everything except the second minute of input
1093 ffmpeg -i INPUT -af atrim=60:120
1097 keep only the first 1000 samples
1099 ffmpeg -i INPUT -af atrim=end_sample=1000
1106 Apply a two-pole Butterworth band-pass filter with central
1107 frequency @var{frequency}, and (3dB-point) band-width width.
1108 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1109 instead of the default: constant 0dB peak gain.
1110 The filter roll off at 6dB per octave (20dB per decade).
1112 The filter accepts the following options:
1116 Set the filter's central frequency. Default is @code{3000}.
1119 Constant skirt gain if set to 1. Defaults to 0.
1122 Set method to specify band-width of filter.
1135 Specify the band-width of a filter in width_type units.
1140 Apply a two-pole Butterworth band-reject filter with central
1141 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1142 The filter roll off at 6dB per octave (20dB per decade).
1144 The filter accepts the following options:
1148 Set the filter's central frequency. Default is @code{3000}.
1151 Set method to specify band-width of filter.
1164 Specify the band-width of a filter in width_type units.
1169 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1170 shelving filter with a response similar to that of a standard
1171 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1173 The filter accepts the following options:
1177 Give the gain at 0 Hz. Its useful range is about -20
1178 (for a large cut) to +20 (for a large boost).
1179 Beware of clipping when using a positive gain.
1182 Set the filter's central frequency and so can be used
1183 to extend or reduce the frequency range to be boosted or cut.
1184 The default value is @code{100} Hz.
1187 Set method to specify band-width of filter.
1200 Determine how steep is the filter's shelf transition.
1205 Apply a biquad IIR filter with the given coefficients.
1206 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1207 are the numerator and denominator coefficients respectively.
1211 Remap input channels to new locations.
1213 This filter accepts the following named parameters:
1215 @item channel_layout
1216 Channel layout of the output stream.
1219 Map channels from input to output. The argument is a '|'-separated list of
1220 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1221 @var{in_channel} form. @var{in_channel} can be either the name of the input
1222 channel (e.g. FL for front left) or its index in the input channel layout.
1223 @var{out_channel} is the name of the output channel or its index in the output
1224 channel layout. If @var{out_channel} is not given then it is implicitly an
1225 index, starting with zero and increasing by one for each mapping.
1228 If no mapping is present, the filter will implicitly map input channels to
1229 output channels preserving index.
1231 For example, assuming a 5.1+downmix input MOV file
1233 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1235 will create an output WAV file tagged as stereo from the downmix channels of
1238 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1240 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1243 @section channelsplit
1245 Split each channel in input audio stream into a separate output stream.
1247 This filter accepts the following named parameters:
1249 @item channel_layout
1250 Channel layout of the input stream. Default is "stereo".
1253 For example, assuming a stereo input MP3 file
1255 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1257 will create an output Matroska file with two audio streams, one containing only
1258 the left channel and the other the right channel.
1260 To split a 5.1 WAV file into per-channel files
1262 ffmpeg -i in.wav -filter_complex
1263 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1264 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1265 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1270 Compress or expand audio dynamic range.
1272 A description of the accepted options follows.
1278 Set list of times in seconds for each channel over which the instantaneous level
1279 of the input signal is averaged to determine its volume. @var{attacks} refers to
1280 increase of volume and @var{decays} refers to decrease of volume. For most
1281 situations, the attack time (response to the audio getting louder) should be
1282 shorter than the decay time because the human ear is more sensitive to sudden
1283 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1284 a typical value for decay is 0.8 seconds.
1287 Set list of points for the transfer function, specified in dB relative to the
1288 maximum possible signal amplitude. Each key points list must be defined using
1289 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1290 @code{x0/y0 x1/y1 x2/y2 ....}
1292 The input values must be in strictly increasing order but the transfer function
1293 does not have to be monotonically rising. The point @code{0/0} is assumed but
1294 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1295 function are @code{-70/-70|-60/-20}.
1298 Set the curve radius in dB for all joints. Defaults to 0.01.
1301 Set additional gain in dB to be applied at all points on the transfer function.
1302 This allows easy adjustment of the overall gain. Defaults to 0.
1305 Set initial volume in dB to be assumed for each channel when filtering starts.
1306 This permits the user to supply a nominal level initially, so that, for
1307 example, a very large gain is not applied to initial signal levels before the
1308 companding has begun to operate. A typical value for audio which is initially
1309 quiet is -90 dB. Defaults to 0.
1312 Set delay in seconds. The input audio is analyzed immediately, but audio is
1313 delayed before being fed to the volume adjuster. Specifying a delay
1314 approximately equal to the attack/decay times allows the filter to effectively
1315 operate in predictive rather than reactive mode. Defaults to 0.
1319 @subsection Examples
1323 Make music with both quiet and loud passages suitable for listening in a noisy
1326 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1330 Noise gate for when the noise is at a lower level than the signal:
1332 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1336 Here is another noise gate, this time for when the noise is at a higher level
1337 than the signal (making it, in some ways, similar to squelch):
1339 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1345 Make audio easier to listen to on headphones.
1347 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1348 so that when listened to on headphones the stereo image is moved from
1349 inside your head (standard for headphones) to outside and in front of
1350 the listener (standard for speakers).
1356 Apply a two-pole peaking equalisation (EQ) filter. With this
1357 filter, the signal-level at and around a selected frequency can
1358 be increased or decreased, whilst (unlike bandpass and bandreject
1359 filters) that at all other frequencies is unchanged.
1361 In order to produce complex equalisation curves, this filter can
1362 be given several times, each with a different central frequency.
1364 The filter accepts the following options:
1368 Set the filter's central frequency in Hz.
1371 Set method to specify band-width of filter.
1384 Specify the band-width of a filter in width_type units.
1387 Set the required gain or attenuation in dB.
1388 Beware of clipping when using a positive gain.
1391 @subsection Examples
1394 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1396 equalizer=f=1000:width_type=h:width=200:g=-10
1400 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1402 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1408 Apply a high-pass filter with 3dB point frequency.
1409 The filter can be either single-pole, or double-pole (the default).
1410 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1412 The filter accepts the following options:
1416 Set frequency in Hz. Default is 3000.
1419 Set number of poles. Default is 2.
1422 Set method to specify band-width of filter.
1435 Specify the band-width of a filter in width_type units.
1436 Applies only to double-pole filter.
1437 The default is 0.707q and gives a Butterworth response.
1442 Join multiple input streams into one multi-channel stream.
1444 The filter accepts the following named parameters:
1448 Number of input streams. Defaults to 2.
1450 @item channel_layout
1451 Desired output channel layout. Defaults to stereo.
1454 Map channels from inputs to output. The argument is a '|'-separated list of
1455 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1456 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1457 can be either the name of the input channel (e.g. FL for front left) or its
1458 index in the specified input stream. @var{out_channel} is the name of the output
1462 The filter will attempt to guess the mappings when those are not specified
1463 explicitly. It does so by first trying to find an unused matching input channel
1464 and if that fails it picks the first unused input channel.
1466 E.g. to join 3 inputs (with properly set channel layouts)
1468 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1471 To build a 5.1 output from 6 single-channel streams:
1473 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1474 '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'
1480 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1482 To enable compilation of this filter you need to configure FFmpeg with
1483 @code{--enable-ladspa}.
1487 Specifies the name of LADSPA plugin library to load. If the environment
1488 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1489 each one of the directories specified by the colon separated list in
1490 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1491 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1492 @file{/usr/lib/ladspa/}.
1495 Specifies the plugin within the library. Some libraries contain only
1496 one plugin, but others contain many of them. If this is not set filter
1497 will list all available plugins within the specified library.
1500 Set the '|' separated list of controls which are zero or more floating point
1501 values that determine the behavior of the loaded plugin (for example delay,
1503 Controls need to be defined using the following syntax:
1504 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1505 @var{valuei} is the value set on the @var{i}-th control.
1506 If @option{controls} is set to @code{help}, all available controls and
1507 their valid ranges are printed.
1509 @item sample_rate, s
1510 Specify the sample rate, default to 44100. Only used if plugin have
1514 Set the number of samples per channel per each output frame, default
1515 is 1024. Only used if plugin have zero inputs.
1518 Set the minimum duration of the sourced audio. See the function
1519 @code{av_parse_time()} for the accepted format, also check the "Time duration"
1520 section in the ffmpeg-utils manual.
1521 Note that the resulting duration may be greater than the specified duration,
1522 as the generated audio is always cut at the end of a complete frame.
1523 If not specified, or the expressed duration is negative, the audio is
1524 supposed to be generated forever.
1525 Only used if plugin have zero inputs.
1529 @subsection Examples
1533 List all available plugins within amp (LADSPA example plugin) library:
1539 List all available controls and their valid ranges for @code{vcf_notch}
1540 plugin from @code{VCF} library:
1542 ladspa=f=vcf:p=vcf_notch:c=help
1546 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1549 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1553 Add reverberation to the audio using TAP-plugins
1554 (Tom's Audio Processing plugins):
1556 ladspa=file=tap_reverb:tap_reverb
1560 Generate white noise, with 0.2 amplitude:
1562 ladspa=file=cmt:noise_source_white:c=c0=.2
1566 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1567 @code{C* Audio Plugin Suite} (CAPS) library:
1569 ladspa=file=caps:Click:c=c1=20'
1573 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1575 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1579 @subsection Commands
1581 This filter supports the following commands:
1584 Modify the @var{N}-th control value.
1586 If the specified value is not valid, it is ignored and prior one is kept.
1591 Apply a low-pass filter with 3dB point frequency.
1592 The filter can be either single-pole or double-pole (the default).
1593 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1595 The filter accepts the following options:
1599 Set frequency in Hz. Default is 500.
1602 Set number of poles. Default is 2.
1605 Set method to specify band-width of filter.
1618 Specify the band-width of a filter in width_type units.
1619 Applies only to double-pole filter.
1620 The default is 0.707q and gives a Butterworth response.
1625 Mix channels with specific gain levels. The filter accepts the output
1626 channel layout followed by a set of channels definitions.
1628 This filter is also designed to remap efficiently the channels of an audio
1631 The filter accepts parameters of the form:
1632 "@var{l}:@var{outdef}:@var{outdef}:..."
1636 output channel layout or number of channels
1639 output channel specification, of the form:
1640 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1643 output channel to define, either a channel name (FL, FR, etc.) or a channel
1644 number (c0, c1, etc.)
1647 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1650 input channel to use, see out_name for details; it is not possible to mix
1651 named and numbered input channels
1654 If the `=' in a channel specification is replaced by `<', then the gains for
1655 that specification will be renormalized so that the total is 1, thus
1656 avoiding clipping noise.
1658 @subsection Mixing examples
1660 For example, if you want to down-mix from stereo to mono, but with a bigger
1661 factor for the left channel:
1663 pan=1:c0=0.9*c0+0.1*c1
1666 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1667 7-channels surround:
1669 pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1672 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1673 that should be preferred (see "-ac" option) unless you have very specific
1676 @subsection Remapping examples
1678 The channel remapping will be effective if, and only if:
1681 @item gain coefficients are zeroes or ones,
1682 @item only one input per channel output,
1685 If all these conditions are satisfied, the filter will notify the user ("Pure
1686 channel mapping detected"), and use an optimized and lossless method to do the
1689 For example, if you have a 5.1 source and want a stereo audio stream by
1690 dropping the extra channels:
1692 pan="stereo: c0=FL : c1=FR"
1695 Given the same source, you can also switch front left and front right channels
1696 and keep the input channel layout:
1698 pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
1701 If the input is a stereo audio stream, you can mute the front left channel (and
1702 still keep the stereo channel layout) with:
1707 Still with a stereo audio stream input, you can copy the right channel in both
1708 front left and right:
1710 pan="stereo: c0=FR : c1=FR"
1715 ReplayGain scanner filter. This filter takes an audio stream as an input and
1716 outputs it unchanged.
1717 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1721 Convert the audio sample format, sample rate and channel layout. This filter is
1722 not meant to be used directly.
1724 @section silencedetect
1726 Detect silence in an audio stream.
1728 This filter logs a message when it detects that the input audio volume is less
1729 or equal to a noise tolerance value for a duration greater or equal to the
1730 minimum detected noise duration.
1732 The printed times and duration are expressed in seconds.
1734 The filter accepts the following options:
1738 Set silence duration until notification (default is 2 seconds).
1741 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1742 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1745 @subsection Examples
1749 Detect 5 seconds of silence with -50dB noise tolerance:
1751 silencedetect=n=-50dB:d=5
1755 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1756 tolerance in @file{silence.mp3}:
1758 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1764 Boost or cut treble (upper) frequencies of the audio using a two-pole
1765 shelving filter with a response similar to that of a standard
1766 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1768 The filter accepts the following options:
1772 Give the gain at whichever is the lower of ~22 kHz and the
1773 Nyquist frequency. Its useful range is about -20 (for a large cut)
1774 to +20 (for a large boost). Beware of clipping when using a positive gain.
1777 Set the filter's central frequency and so can be used
1778 to extend or reduce the frequency range to be boosted or cut.
1779 The default value is @code{3000} Hz.
1782 Set method to specify band-width of filter.
1795 Determine how steep is the filter's shelf transition.
1800 Adjust the input audio volume.
1802 The filter accepts the following options:
1807 Set audio volume expression.
1809 Output values are clipped to the maximum value.
1811 The output audio volume is given by the relation:
1813 @var{output_volume} = @var{volume} * @var{input_volume}
1816 Default value for @var{volume} is "1.0".
1819 Set the mathematical precision.
1821 This determines which input sample formats will be allowed, which affects the
1822 precision of the volume scaling.
1826 8-bit fixed-point; limits input sample format to U8, S16, and S32.
1828 32-bit floating-point; limits input sample format to FLT. (default)
1830 64-bit floating-point; limits input sample format to DBL.
1834 Behaviour on encountering ReplayGain side data in input frames.
1838 Remove ReplayGain side data, ignoring its contents (the default).
1841 Ignore ReplayGain side data, but leave it in the frame.
1844 Prefer track gain, if present.
1847 Prefer album gain, if present.
1850 @item replaygain_preamp
1851 Pre-amplification gain in dB to apply to the selected replaygain gain.
1853 Default value for @var{replaygain_preamp} is 0.0.
1856 Set when the volume expression is evaluated.
1858 It accepts the following values:
1861 only evaluate expression once during the filter initialization, or
1862 when the @samp{volume} command is sent
1865 evaluate expression for each incoming frame
1868 Default value is @samp{once}.
1871 The volume expression can contain the following parameters.
1875 frame number (starting at zero)
1878 @item nb_consumed_samples
1879 number of samples consumed by the filter
1881 number of samples in the current frame
1883 original frame position in the file
1889 PTS at start of stream
1891 time at start of stream
1897 last set volume value
1900 Note that when @option{eval} is set to @samp{once} only the
1901 @var{sample_rate} and @var{tb} variables are available, all other
1902 variables will evaluate to NAN.
1904 @subsection Commands
1906 This filter supports the following commands:
1909 Modify the volume expression.
1910 The command accepts the same syntax of the corresponding option.
1912 If the specified expression is not valid, it is kept at its current
1916 @subsection Examples
1920 Halve the input audio volume:
1924 volume=volume=-6.0206dB
1927 In all the above example the named key for @option{volume} can be
1928 omitted, for example like in:
1934 Increase input audio power by 6 decibels using fixed-point precision:
1936 volume=volume=6dB:precision=fixed
1940 Fade volume after time 10 with an annihilation period of 5 seconds:
1942 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
1946 @section volumedetect
1948 Detect the volume of the input video.
1950 The filter has no parameters. The input is not modified. Statistics about
1951 the volume will be printed in the log when the input stream end is reached.
1953 In particular it will show the mean volume (root mean square), maximum
1954 volume (on a per-sample basis), and the beginning of a histogram of the
1955 registered volume values (from the maximum value to a cumulated 1/1000 of
1958 All volumes are in decibels relative to the maximum PCM value.
1960 @subsection Examples
1962 Here is an excerpt of the output:
1964 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
1965 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
1966 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
1967 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
1968 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
1969 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
1970 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
1971 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
1972 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
1978 The mean square energy is approximately -27 dB, or 10^-2.7.
1980 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
1982 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
1985 In other words, raising the volume by +4 dB does not cause any clipping,
1986 raising it by +5 dB causes clipping for 6 samples, etc.
1988 @c man end AUDIO FILTERS
1990 @chapter Audio Sources
1991 @c man begin AUDIO SOURCES
1993 Below is a description of the currently available audio sources.
1997 Buffer audio frames, and make them available to the filter chain.
1999 This source is mainly intended for a programmatic use, in particular
2000 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2002 It accepts the following named parameters:
2007 Timebase which will be used for timestamps of submitted frames. It must be
2008 either a floating-point number or in @var{numerator}/@var{denominator} form.
2011 The sample rate of the incoming audio buffers.
2014 The sample format of the incoming audio buffers.
2015 Either a sample format name or its corresponging integer representation from
2016 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2018 @item channel_layout
2019 The channel layout of the incoming audio buffers.
2020 Either a channel layout name from channel_layout_map in
2021 @file{libavutil/channel_layout.c} or its corresponding integer representation
2022 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2025 The number of channels of the incoming audio buffers.
2026 If both @var{channels} and @var{channel_layout} are specified, then they
2031 @subsection Examples
2034 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2037 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2038 Since the sample format with name "s16p" corresponds to the number
2039 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2042 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2047 Generate an audio signal specified by an expression.
2049 This source accepts in input one or more expressions (one for each
2050 channel), which are evaluated and used to generate a corresponding
2053 This source accepts the following options:
2057 Set the '|'-separated expressions list for each separate channel. In case the
2058 @option{channel_layout} option is not specified, the selected channel layout
2059 depends on the number of provided expressions. Otherwise the last
2060 specified expression is applied to the remaining output channels.
2062 @item channel_layout, c
2063 Set the channel layout. The number of channels in the specified layout
2064 must be equal to the number of specified expressions.
2067 Set the minimum duration of the sourced audio. See the function
2068 @code{av_parse_time()} for the accepted format.
2069 Note that the resulting duration may be greater than the specified
2070 duration, as the generated audio is always cut at the end of a
2073 If not specified, or the expressed duration is negative, the audio is
2074 supposed to be generated forever.
2077 Set the number of samples per channel per each output frame,
2080 @item sample_rate, s
2081 Specify the sample rate, default to 44100.
2084 Each expression in @var{exprs} can contain the following constants:
2088 number of the evaluated sample, starting from 0
2091 time of the evaluated sample expressed in seconds, starting from 0
2098 @subsection Examples
2108 Generate a sin signal with frequency of 440 Hz, set sample rate to
2111 aevalsrc="sin(440*2*PI*t):s=8000"
2115 Generate a two channels signal, specify the channel layout (Front
2116 Center + Back Center) explicitly:
2118 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2122 Generate white noise:
2124 aevalsrc="-2+random(0)"
2128 Generate an amplitude modulated signal:
2130 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2134 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2136 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2143 Null audio source, return unprocessed audio frames. It is mainly useful
2144 as a template and to be employed in analysis / debugging tools, or as
2145 the source for filters which ignore the input data (for example the sox
2148 This source accepts the following options:
2152 @item channel_layout, cl
2154 Specify the channel layout, and can be either an integer or a string
2155 representing a channel layout. The default value of @var{channel_layout}
2158 Check the channel_layout_map definition in
2159 @file{libavutil/channel_layout.c} for the mapping between strings and
2160 channel layout values.
2162 @item sample_rate, r
2163 Specify the sample rate, and defaults to 44100.
2166 Set the number of samples per requested frames.
2170 @subsection Examples
2174 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2176 anullsrc=r=48000:cl=4
2180 Do the same operation with a more obvious syntax:
2182 anullsrc=r=48000:cl=mono
2186 All the parameters need to be explicitly defined.
2190 Synthesize a voice utterance using the libflite library.
2192 To enable compilation of this filter you need to configure FFmpeg with
2193 @code{--enable-libflite}.
2195 Note that the flite library is not thread-safe.
2197 The filter accepts the following options:
2202 If set to 1, list the names of the available voices and exit
2203 immediately. Default value is 0.
2206 Set the maximum number of samples per frame. Default value is 512.
2209 Set the filename containing the text to speak.
2212 Set the text to speak.
2215 Set the voice to use for the speech synthesis. Default value is
2216 @code{kal}. See also the @var{list_voices} option.
2219 @subsection Examples
2223 Read from file @file{speech.txt}, and synthetize the text using the
2224 standard flite voice:
2226 flite=textfile=speech.txt
2230 Read the specified text selecting the @code{slt} voice:
2232 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2236 Input text to ffmpeg:
2238 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2242 Make @file{ffplay} speak the specified text, using @code{flite} and
2243 the @code{lavfi} device:
2245 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2249 For more information about libflite, check:
2250 @url{http://www.speech.cs.cmu.edu/flite/}
2254 Generate an audio signal made of a sine wave with amplitude 1/8.
2256 The audio signal is bit-exact.
2258 The filter accepts the following options:
2263 Set the carrier frequency. Default is 440 Hz.
2265 @item beep_factor, b
2266 Enable a periodic beep every second with frequency @var{beep_factor} times
2267 the carrier frequency. Default is 0, meaning the beep is disabled.
2269 @item sample_rate, r
2270 Specify the sample rate, default is 44100.
2273 Specify the duration of the generated audio stream.
2275 @item samples_per_frame
2276 Set the number of samples per output frame, default is 1024.
2279 @subsection Examples
2284 Generate a simple 440 Hz sine wave:
2290 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2294 sine=frequency=220:beep_factor=4:duration=5
2299 @c man end AUDIO SOURCES
2301 @chapter Audio Sinks
2302 @c man begin AUDIO SINKS
2304 Below is a description of the currently available audio sinks.
2306 @section abuffersink
2308 Buffer audio frames, and make them available to the end of filter chain.
2310 This sink is mainly intended for programmatic use, in particular
2311 through the interface defined in @file{libavfilter/buffersink.h}
2312 or the options system.
2314 It accepts a pointer to an AVABufferSinkContext structure, which
2315 defines the incoming buffers' formats, to be passed as the opaque
2316 parameter to @code{avfilter_init_filter} for initialization.
2320 Null audio sink, do absolutely nothing with the input audio. It is
2321 mainly useful as a template and to be employed in analysis / debugging
2324 @c man end AUDIO SINKS
2326 @chapter Video Filters
2327 @c man begin VIDEO FILTERS
2329 When you configure your FFmpeg build, you can disable any of the
2330 existing filters using @code{--disable-filters}.
2331 The configure output will show the video filters included in your
2334 Below is a description of the currently available video filters.
2336 @section alphaextract
2338 Extract the alpha component from the input as a grayscale video. This
2339 is especially useful with the @var{alphamerge} filter.
2343 Add or replace the alpha component of the primary input with the
2344 grayscale value of a second input. This is intended for use with
2345 @var{alphaextract} to allow the transmission or storage of frame
2346 sequences that have alpha in a format that doesn't support an alpha
2349 For example, to reconstruct full frames from a normal YUV-encoded video
2350 and a separate video created with @var{alphaextract}, you might use:
2352 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2355 Since this filter is designed for reconstruction, it operates on frame
2356 sequences without considering timestamps, and terminates when either
2357 input reaches end of stream. This will cause problems if your encoding
2358 pipeline drops frames. If you're trying to apply an image as an
2359 overlay to a video stream, consider the @var{overlay} filter instead.
2363 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2364 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2365 Substation Alpha) subtitles files.
2369 Compute the bounding box for the non-black pixels in the input frame
2372 This filter computes the bounding box containing all the pixels with a
2373 luminance value greater than the minimum allowed value.
2374 The parameters describing the bounding box are printed on the filter
2377 The filter accepts the following option:
2381 Set the minimal luminance value. Default is @code{16}.
2384 @section blackdetect
2386 Detect video intervals that are (almost) completely black. Can be
2387 useful to detect chapter transitions, commercials, or invalid
2388 recordings. Output lines contains the time for the start, end and
2389 duration of the detected black interval expressed in seconds.
2391 In order to display the output lines, you need to set the loglevel at
2392 least to the AV_LOG_INFO value.
2394 The filter accepts the following options:
2397 @item black_min_duration, d
2398 Set the minimum detected black duration expressed in seconds. It must
2399 be a non-negative floating point number.
2401 Default value is 2.0.
2403 @item picture_black_ratio_th, pic_th
2404 Set the threshold for considering a picture "black".
2405 Express the minimum value for the ratio:
2407 @var{nb_black_pixels} / @var{nb_pixels}
2410 for which a picture is considered black.
2411 Default value is 0.98.
2413 @item pixel_black_th, pix_th
2414 Set the threshold for considering a pixel "black".
2416 The threshold expresses the maximum pixel luminance value for which a
2417 pixel is considered "black". The provided value is scaled according to
2418 the following equation:
2420 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2423 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2424 the input video format, the range is [0-255] for YUV full-range
2425 formats and [16-235] for YUV non full-range formats.
2427 Default value is 0.10.
2430 The following example sets the maximum pixel threshold to the minimum
2431 value, and detects only black intervals of 2 or more seconds:
2433 blackdetect=d=2:pix_th=0.00
2438 Detect frames that are (almost) completely black. Can be useful to
2439 detect chapter transitions or commercials. Output lines consist of
2440 the frame number of the detected frame, the percentage of blackness,
2441 the position in the file if known or -1 and the timestamp in seconds.
2443 In order to display the output lines, you need to set the loglevel at
2444 least to the AV_LOG_INFO value.
2446 The filter accepts the following options:
2451 Set the percentage of the pixels that have to be below the threshold, defaults
2454 @item threshold, thresh
2455 Set the threshold below which a pixel value is considered black, defaults to
2462 Blend two video frames into each other.
2464 It takes two input streams and outputs one stream, the first input is the
2465 "top" layer and second input is "bottom" layer.
2466 Output terminates when shortest input terminates.
2468 A description of the accepted options follows.
2476 Set blend mode for specific pixel component or all pixel components in case
2477 of @var{all_mode}. Default value is @code{normal}.
2479 Available values for component modes are:
2512 Set blend opacity for specific pixel component or all pixel components in case
2513 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2520 Set blend expression for specific pixel component or all pixel components in case
2521 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2523 The expressions can use the following variables:
2527 The sequential number of the filtered frame, starting from @code{0}.
2531 the coordinates of the current sample
2535 the width and height of currently filtered plane
2539 Width and height scale depending on the currently filtered plane. It is the
2540 ratio between the corresponding luma plane number of pixels and the current
2541 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2542 @code{0.5,0.5} for chroma planes.
2545 Time of the current frame, expressed in seconds.
2548 Value of pixel component at current location for first video frame (top layer).
2551 Value of pixel component at current location for second video frame (bottom layer).
2555 Force termination when the shortest input terminates. Default is @code{0}.
2557 Continue applying the last bottom frame after the end of the stream. A value of
2558 @code{0} disable the filter after the last frame of the bottom layer is reached.
2559 Default is @code{1}.
2562 @subsection Examples
2566 Apply transition from bottom layer to top layer in first 10 seconds:
2568 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2572 Apply 1x1 checkerboard effect:
2574 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2578 Apply uncover left effect:
2580 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2584 Apply uncover down effect:
2586 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2590 Apply uncover up-left effect:
2592 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2598 Apply boxblur algorithm to the input video.
2600 The filter accepts the following options:
2604 @item luma_radius, lr
2605 @item luma_power, lp
2606 @item chroma_radius, cr
2607 @item chroma_power, cp
2608 @item alpha_radius, ar
2609 @item alpha_power, ap
2613 A description of the accepted options follows.
2616 @item luma_radius, lr
2617 @item chroma_radius, cr
2618 @item alpha_radius, ar
2619 Set an expression for the box radius in pixels used for blurring the
2620 corresponding input plane.
2622 The radius value must be a non-negative number, and must not be
2623 greater than the value of the expression @code{min(w,h)/2} for the
2624 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2627 Default value for @option{luma_radius} is "2". If not specified,
2628 @option{chroma_radius} and @option{alpha_radius} default to the
2629 corresponding value set for @option{luma_radius}.
2631 The expressions can contain the following constants:
2635 the input width and height in pixels
2639 the input chroma image width and height in pixels
2643 horizontal and vertical chroma subsample values. For example for the
2644 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2647 @item luma_power, lp
2648 @item chroma_power, cp
2649 @item alpha_power, ap
2650 Specify how many times the boxblur filter is applied to the
2651 corresponding plane.
2653 Default value for @option{luma_power} is 2. If not specified,
2654 @option{chroma_power} and @option{alpha_power} default to the
2655 corresponding value set for @option{luma_power}.
2657 A value of 0 will disable the effect.
2660 @subsection Examples
2664 Apply a boxblur filter with luma, chroma, and alpha radius
2667 boxblur=luma_radius=2:luma_power=1
2672 Set luma radius to 2, alpha and chroma radius to 0:
2674 boxblur=2:1:cr=0:ar=0
2678 Set luma and chroma radius to a fraction of the video dimension:
2680 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2684 @section colorbalance
2685 Modify intensity of primary colors (red, green and blue) of input frames.
2687 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2688 regions for the red-cyan, green-magenta or blue-yellow balance.
2690 A positive adjustment value shifts the balance towards the primary color, a negative
2691 value towards the complementary color.
2693 The filter accepts the following options:
2699 Adjust red, green and blue shadows (darkest pixels).
2704 Adjust red, green and blue midtones (medium pixels).
2709 Adjust red, green and blue highlights (brightest pixels).
2711 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2714 @subsection Examples
2718 Add red color cast to shadows:
2724 @section colorchannelmixer
2726 Adjust video input frames by re-mixing color channels.
2728 This filter modifies a color channel by adding the values associated to
2729 the other channels of the same pixels. For example if the value to
2730 modify is red, the output value will be:
2732 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2735 The filter accepts the following options:
2742 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2743 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2749 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2750 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2756 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2757 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2763 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2764 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2766 Allowed ranges for options are @code{[-2.0, 2.0]}.
2769 @subsection Examples
2773 Convert source to grayscale:
2775 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2778 Simulate sepia tones:
2780 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
2784 @section colormatrix
2786 Convert color matrix.
2788 The filter accepts the following options:
2793 Specify the source and destination color matrix. Both values must be
2796 The accepted values are:
2812 For example to convert from BT.601 to SMPTE-240M, use the command:
2814 colormatrix=bt601:smpte240m
2819 Copy the input source unchanged to the output. Mainly useful for
2824 Crop the input video to given dimensions.
2826 The filter accepts the following options:
2830 Width of the output video. It defaults to @code{iw}.
2831 This expression is evaluated only once during the filter
2835 Height of the output video. It defaults to @code{ih}.
2836 This expression is evaluated only once during the filter
2840 Horizontal position, in the input video, of the left edge of the output video.
2841 It defaults to @code{(in_w-out_w)/2}.
2842 This expression is evaluated per-frame.
2845 Vertical position, in the input video, of the top edge of the output video.
2846 It defaults to @code{(in_h-out_h)/2}.
2847 This expression is evaluated per-frame.
2850 If set to 1 will force the output display aspect ratio
2851 to be the same of the input, by changing the output sample aspect
2852 ratio. It defaults to 0.
2855 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
2856 expressions containing the following constants:
2861 the computed values for @var{x} and @var{y}. They are evaluated for
2866 the input width and height
2870 same as @var{in_w} and @var{in_h}
2874 the output (cropped) width and height
2878 same as @var{out_w} and @var{out_h}
2881 same as @var{iw} / @var{ih}
2884 input sample aspect ratio
2887 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
2891 horizontal and vertical chroma subsample values. For example for the
2892 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2895 the number of input frame, starting from 0
2898 the position in the file of the input frame, NAN if unknown
2901 timestamp expressed in seconds, NAN if the input timestamp is unknown
2905 The expression for @var{out_w} may depend on the value of @var{out_h},
2906 and the expression for @var{out_h} may depend on @var{out_w}, but they
2907 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
2908 evaluated after @var{out_w} and @var{out_h}.
2910 The @var{x} and @var{y} parameters specify the expressions for the
2911 position of the top-left corner of the output (non-cropped) area. They
2912 are evaluated for each frame. If the evaluated value is not valid, it
2913 is approximated to the nearest valid value.
2915 The expression for @var{x} may depend on @var{y}, and the expression
2916 for @var{y} may depend on @var{x}.
2918 @subsection Examples
2922 Crop area with size 100x100 at position (12,34).
2927 Using named options, the example above becomes:
2929 crop=w=100:h=100:x=12:y=34
2933 Crop the central input area with size 100x100:
2939 Crop the central input area with size 2/3 of the input video:
2941 crop=2/3*in_w:2/3*in_h
2945 Crop the input video central square:
2952 Delimit the rectangle with the top-left corner placed at position
2953 100:100 and the right-bottom corner corresponding to the right-bottom
2954 corner of the input image:
2956 crop=in_w-100:in_h-100:100:100
2960 Crop 10 pixels from the left and right borders, and 20 pixels from
2961 the top and bottom borders
2963 crop=in_w-2*10:in_h-2*20
2967 Keep only the bottom right quarter of the input image:
2969 crop=in_w/2:in_h/2:in_w/2:in_h/2
2973 Crop height for getting Greek harmony:
2975 crop=in_w:1/PHI*in_w
2979 Appply trembling effect:
2981 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)
2985 Apply erratic camera effect depending on timestamp:
2987 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)"
2991 Set x depending on the value of y:
2993 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
2999 Auto-detect crop size.
3001 Calculate necessary cropping parameters and prints the recommended
3002 parameters through the logging system. The detected dimensions
3003 correspond to the non-black area of the input video.
3005 The filter accepts the following options:
3010 Set higher black value threshold, which can be optionally specified
3011 from nothing (0) to everything (255). An intensity value greater
3012 to the set value is considered non-black. Default value is 24.
3015 Set the value for which the width/height should be divisible by. The
3016 offset is automatically adjusted to center the video. Use 2 to get
3017 only even dimensions (needed for 4:2:2 video). 16 is best when
3018 encoding to most video codecs. Default value is 16.
3020 @item reset_count, reset
3021 Set the counter that determines after how many frames cropdetect will
3022 reset the previously detected largest video area and start over to
3023 detect the current optimal crop area. Default value is 0.
3025 This can be useful when channel logos distort the video area. 0
3026 indicates never reset and return the largest area encountered during
3033 Apply color adjustments using curves.
3035 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3036 component (red, green and blue) has its values defined by @var{N} key points
3037 tied from each other using a smooth curve. The x-axis represents the pixel
3038 values from the input frame, and the y-axis the new pixel values to be set for
3041 By default, a component curve is defined by the two points @var{(0;0)} and
3042 @var{(1;1)}. This creates a straight line where each original pixel value is
3043 "adjusted" to its own value, which means no change to the image.
3045 The filter allows you to redefine these two points and add some more. A new
3046 curve (using a natural cubic spline interpolation) will be define to pass
3047 smoothly through all these new coordinates. The new defined points needs to be
3048 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3049 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3050 the vector spaces, the values will be clipped accordingly.
3052 If there is no key point defined in @code{x=0}, the filter will automatically
3053 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3054 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3056 The filter accepts the following options:
3060 Select one of the available color presets. This option can be used in addition
3061 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3062 options takes priority on the preset values.
3063 Available presets are:
3066 @item color_negative
3069 @item increase_contrast
3071 @item linear_contrast
3072 @item medium_contrast
3074 @item strong_contrast
3077 Default is @code{none}.
3079 Set the master key points. These points will define a second pass mapping. It
3080 is sometimes called a "luminance" or "value" mapping. It can be used with
3081 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3082 post-processing LUT.
3084 Set the key points for the red component.
3086 Set the key points for the green component.
3088 Set the key points for the blue component.
3090 Set the key points for all components (not including master).
3091 Can be used in addition to the other key points component
3092 options. In this case, the unset component(s) will fallback on this
3093 @option{all} setting.
3095 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3098 To avoid some filtergraph syntax conflicts, each key points list need to be
3099 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3101 @subsection Examples
3105 Increase slightly the middle level of blue:
3107 curves=blue='0.5/0.58'
3113 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3115 Here we obtain the following coordinates for each components:
3118 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3120 @code{(0;0) (0.50;0.48) (1;1)}
3122 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3126 The previous example can also be achieved with the associated built-in preset:
3128 curves=preset=vintage
3138 Use a Photoshop preset and redefine the points of the green component:
3140 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3146 Denoise frames using 2D DCT (frequency domain filtering).
3148 This filter is not designed for real time and can be extremely slow.
3150 The filter accepts the following options:
3154 Set the noise sigma constant.
3156 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3157 coefficient (absolute value) below this threshold with be dropped.
3159 If you need a more advanced filtering, see @option{expr}.
3161 Default is @code{0}.
3164 Set number overlapping pixels for each block. Each block is of size
3165 @code{16x16}. Since the filter can be slow, you may want to reduce this value,
3166 at the cost of a less effective filter and the risk of various artefacts.
3168 If the overlapping value doesn't allow to process the whole input width or
3169 height, a warning will be displayed and according borders won't be denoised.
3171 Default value is @code{15}.
3174 Set the coefficient factor expression.
3176 For each coefficient of a DCT block, this expression will be evaluated as a
3177 multiplier value for the coefficient.
3179 If this is option is set, the @option{sigma} option will be ignored.
3181 The absolute value of the coefficient can be accessed through the @var{c}
3185 @subsection Examples
3187 Apply a denoise with a @option{sigma} of @code{4.5}:
3192 The same operation can be achieved using the expression system:
3194 dctdnoiz=e='gte(c, 4.5*3)'
3200 Drop duplicated frames at regular intervals.
3202 The filter accepts the following options:
3206 Set the number of frames from which one will be dropped. Setting this to
3207 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3208 Default is @code{5}.
3211 Set the threshold for duplicate detection. If the difference metric for a frame
3212 is less than or equal to this value, then it is declared as duplicate. Default
3216 Set scene change threshold. Default is @code{15}.
3220 Set the size of the x and y-axis blocks used during metric calculations.
3221 Larger blocks give better noise suppression, but also give worse detection of
3222 small movements. Must be a power of two. Default is @code{32}.
3225 Mark main input as a pre-processed input and activate clean source input
3226 stream. This allows the input to be pre-processed with various filters to help
3227 the metrics calculation while keeping the frame selection lossless. When set to
3228 @code{1}, the first stream is for the pre-processed input, and the second
3229 stream is the clean source from where the kept frames are chosen. Default is
3233 Set whether or not chroma is considered in the metric calculations. Default is
3239 Remove judder produced by partially interlaced telecined content.
3241 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3242 source was partially telecined content then the output of @code{pullup,dejudder}
3243 will have a variable frame rate. May change the recorded frame rate of the
3244 container. Aside from that change, this filter will not affect constant frame
3247 The option available in this filter is:
3251 Specify the length of the window over which the judder repeats.
3253 Accepts any interger greater than 1. Useful values are:
3257 If the original was telecined from 24 to 30 fps (Film to NTSC).
3260 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3263 If a mixture of the two.
3266 The default is @samp{4}.
3271 Suppress a TV station logo by a simple interpolation of the surrounding
3272 pixels. Just set a rectangle covering the logo and watch it disappear
3273 (and sometimes something even uglier appear - your mileage may vary).
3275 This filter accepts the following options:
3280 Specify the top left corner coordinates of the logo. They must be
3285 Specify the width and height of the logo to clear. They must be
3289 Specify the thickness of the fuzzy edge of the rectangle (added to
3290 @var{w} and @var{h}). The default value is 4.
3293 When set to 1, a green rectangle is drawn on the screen to simplify
3294 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3295 The default value is 0.
3297 The rectangle is drawn on the outermost pixels which will be (partly)
3298 replaced with interpolated values. The values of the next pixels
3299 immediately outside this rectangle in each direction will be used to
3300 compute the interpolated pixel values inside the rectangle.
3304 @subsection Examples
3308 Set a rectangle covering the area with top left corner coordinates 0,0
3309 and size 100x77, setting a band of size 10:
3311 delogo=x=0:y=0:w=100:h=77:band=10
3318 Attempt to fix small changes in horizontal and/or vertical shift. This
3319 filter helps remove camera shake from hand-holding a camera, bumping a
3320 tripod, moving on a vehicle, etc.
3322 The filter accepts the following options:
3330 Specify a rectangular area where to limit the search for motion
3332 If desired the search for motion vectors can be limited to a
3333 rectangular area of the frame defined by its top left corner, width
3334 and height. These parameters have the same meaning as the drawbox
3335 filter which can be used to visualise the position of the bounding
3338 This is useful when simultaneous movement of subjects within the frame
3339 might be confused for camera motion by the motion vector search.
3341 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3342 then the full frame is used. This allows later options to be set
3343 without specifying the bounding box for the motion vector search.
3345 Default - search the whole frame.
3349 Specify the maximum extent of movement in x and y directions in the
3350 range 0-64 pixels. Default 16.
3353 Specify how to generate pixels to fill blanks at the edge of the
3354 frame. Available values are:
3357 Fill zeroes at blank locations
3359 Original image at blank locations
3361 Extruded edge value at blank locations
3363 Mirrored edge at blank locations
3365 Default value is @samp{mirror}.
3368 Specify the blocksize to use for motion search. Range 4-128 pixels,
3372 Specify the contrast threshold for blocks. Only blocks with more than
3373 the specified contrast (difference between darkest and lightest
3374 pixels) will be considered. Range 1-255, default 125.
3377 Specify the search strategy. Available values are:
3380 Set exhaustive search
3382 Set less exhaustive search.
3384 Default value is @samp{exhaustive}.
3387 If set then a detailed log of the motion search is written to the
3391 If set to 1, specify using OpenCL capabilities, only available if
3392 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3398 Draw a colored box on the input image.
3400 This filter accepts the following options:
3405 The expressions which specify the top left corner coordinates of the box. Default to 0.
3409 The expressions which specify the width and height of the box, if 0 they are interpreted as
3410 the input width and height. Default to 0.
3413 Specify the color of the box to write. For the general syntax of this option,
3414 check the "Color" section in the ffmpeg-utils manual. If the special
3415 value @code{invert} is used, the box edge color is the same as the
3416 video with inverted luma.
3419 The expression which sets the thickness of the box edge. Default value is @code{3}.
3421 See below for the list of accepted constants.
3424 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3425 following constants:
3429 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3433 horizontal and vertical chroma subsample values. For example for the
3434 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3438 The input width and height.
3441 The input sample aspect ratio.
3445 The x and y offset coordinates where the box is drawn.
3449 The width and height of the drawn box.
3452 The thickness of the drawn box.
3454 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3455 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3459 @subsection Examples
3463 Draw a black box around the edge of the input image:
3469 Draw a box with color red and an opacity of 50%:
3471 drawbox=10:20:200:60:red@@0.5
3474 The previous example can be specified as:
3476 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3480 Fill the box with pink color:
3482 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3486 Draw a 2-pixel red 2.40:1 mask:
3488 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
3494 Draw a grid on the input image.
3496 This filter accepts the following options:
3501 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3505 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3506 input width and height, respectively, minus @code{thickness}, so image gets
3507 framed. Default to 0.
3510 Specify the color of the grid. For the general syntax of this option,
3511 check the "Color" section in the ffmpeg-utils manual. If the special
3512 value @code{invert} is used, the grid color is the same as the
3513 video with inverted luma.
3516 The expression which sets the thickness of the grid line. Default value is @code{1}.
3518 See below for the list of accepted constants.
3521 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3522 following constants:
3526 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3530 horizontal and vertical chroma subsample values. For example for the
3531 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3535 The input grid cell width and height.
3538 The input sample aspect ratio.
3542 The x and y coordinates of some point of grid intersection (meant to configure offset).
3546 The width and height of the drawn cell.
3549 The thickness of the drawn cell.
3551 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3552 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3556 @subsection Examples
3560 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3562 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3566 Draw a white 3x3 grid with an opacity of 50%:
3568 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3575 Draw text string or text from specified file on top of video using the
3576 libfreetype library.
3578 To enable compilation of this filter you need to configure FFmpeg with
3579 @code{--enable-libfreetype}.
3583 The description of the accepted parameters follows.
3588 Used to draw a box around text using background color.
3589 Value should be either 1 (enable) or 0 (disable).
3590 The default value of @var{box} is 0.
3593 The color to be used for drawing box around text. For the syntax of this
3594 option, check the "Color" section in the ffmpeg-utils manual.
3596 The default value of @var{boxcolor} is "white".
3599 Set the width of the border to be drawn around the text using @var{bordercolor}.
3600 The default value of @var{borderw} is 0.
3603 Set the color to be used for drawing border around text. For the syntax of this
3604 option, check the "Color" section in the ffmpeg-utils manual.
3606 The default value of @var{bordercolor} is "black".
3609 Select how the @var{text} is expanded. Can be either @code{none},
3610 @code{strftime} (deprecated) or
3611 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3615 If true, check and fix text coords to avoid clipping.
3618 The color to be used for drawing fonts. For the syntax of this option, check
3619 the "Color" section in the ffmpeg-utils manual.
3621 The default value of @var{fontcolor} is "black".
3624 The font file to be used for drawing text. Path must be included.
3625 This parameter is mandatory.
3628 The font size to be used for drawing text.
3629 The default value of @var{fontsize} is 16.
3632 Flags to be used for loading the fonts.
3634 The flags map the corresponding flags supported by libfreetype, and are
3635 a combination of the following values:
3642 @item vertical_layout
3643 @item force_autohint
3646 @item ignore_global_advance_width
3648 @item ignore_transform
3654 Default value is "default".
3656 For more information consult the documentation for the FT_LOAD_*
3660 The color to be used for drawing a shadow behind the drawn text. For the
3661 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3663 The default value of @var{shadowcolor} is "black".
3667 The x and y offsets for the text shadow position with respect to the
3668 position of the text. They can be either positive or negative
3669 values. Default value for both is "0".
3672 The starting frame number for the n/frame_num variable. The default value
3676 The size in number of spaces to use for rendering the tab.
3680 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3681 format. It can be used with or without text parameter. @var{timecode_rate}
3682 option must be specified.
3684 @item timecode_rate, rate, r
3685 Set the timecode frame rate (timecode only).
3688 The text string to be drawn. The text must be a sequence of UTF-8
3690 This parameter is mandatory if no file is specified with the parameter
3694 A text file containing text to be drawn. The text must be a sequence
3695 of UTF-8 encoded characters.
3697 This parameter is mandatory if no text string is specified with the
3698 parameter @var{text}.
3700 If both @var{text} and @var{textfile} are specified, an error is thrown.
3703 If set to 1, the @var{textfile} will be reloaded before each frame.
3704 Be sure to update it atomically, or it may be read partially, or even fail.
3708 The expressions which specify the offsets where text will be drawn
3709 within the video frame. They are relative to the top/left border of the
3712 The default value of @var{x} and @var{y} is "0".
3714 See below for the list of accepted constants and functions.
3717 The parameters for @var{x} and @var{y} are expressions containing the
3718 following constants and functions:
3722 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3726 horizontal and vertical chroma subsample values. For example for the
3727 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3730 the height of each text line
3738 @item max_glyph_a, ascent
3739 the maximum distance from the baseline to the highest/upper grid
3740 coordinate used to place a glyph outline point, for all the rendered
3742 It is a positive value, due to the grid's orientation with the Y axis
3745 @item max_glyph_d, descent
3746 the maximum distance from the baseline to the lowest grid coordinate
3747 used to place a glyph outline point, for all the rendered glyphs.
3748 This is a negative value, due to the grid's orientation, with the Y axis
3752 maximum glyph height, that is the maximum height for all the glyphs
3753 contained in the rendered text, it is equivalent to @var{ascent} -
3757 maximum glyph width, that is the maximum width for all the glyphs
3758 contained in the rendered text
3761 the number of input frame, starting from 0
3763 @item rand(min, max)
3764 return a random number included between @var{min} and @var{max}
3767 input sample aspect ratio
3770 timestamp expressed in seconds, NAN if the input timestamp is unknown
3773 the height of the rendered text
3776 the width of the rendered text
3780 the x and y offset coordinates where the text is drawn.
3782 These parameters allow the @var{x} and @var{y} expressions to refer
3783 each other, so you can for example specify @code{y=x/dar}.
3786 If libavfilter was built with @code{--enable-fontconfig}, then
3787 @option{fontfile} can be a fontconfig pattern or omitted.
3789 @anchor{drawtext_expansion}
3790 @subsection Text expansion
3792 If @option{expansion} is set to @code{strftime},
3793 the filter recognizes strftime() sequences in the provided text and
3794 expands them accordingly. Check the documentation of strftime(). This
3795 feature is deprecated.
3797 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3799 If @option{expansion} is set to @code{normal} (which is the default),
3800 the following expansion mechanism is used.
3802 The backslash character '\', followed by any character, always expands to
3803 the second character.
3805 Sequence of the form @code{%@{...@}} are expanded. The text between the
3806 braces is a function name, possibly followed by arguments separated by ':'.
3807 If the arguments contain special characters or delimiters (':' or '@}'),
3808 they should be escaped.
3810 Note that they probably must also be escaped as the value for the
3811 @option{text} option in the filter argument string and as the filter
3812 argument in the filtergraph description, and possibly also for the shell,
3813 that makes up to four levels of escaping; using a text file avoids these
3816 The following functions are available:
3821 The expression evaluation result.
3823 It must take one argument specifying the expression to be evaluated,
3824 which accepts the same constants and functions as the @var{x} and
3825 @var{y} values. Note that not all constants should be used, for
3826 example the text size is not known when evaluating the expression, so
3827 the constants @var{text_w} and @var{text_h} will have an undefined
3831 The time at which the filter is running, expressed in UTC.
3832 It can accept an argument: a strftime() format string.
3835 The time at which the filter is running, expressed in the local time zone.
3836 It can accept an argument: a strftime() format string.
3839 Frame metadata. It must take one argument specifying metadata key.
3842 The frame number, starting from 0.
3845 A 1 character description of the current picture type.
3848 The timestamp of the current frame, in seconds, with microsecond accuracy.
3852 @subsection Examples
3856 Draw "Test Text" with font FreeSerif, using the default values for the
3857 optional parameters.
3860 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
3864 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
3865 and y=50 (counting from the top-left corner of the screen), text is
3866 yellow with a red box around it. Both the text and the box have an
3870 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
3871 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
3874 Note that the double quotes are not necessary if spaces are not used
3875 within the parameter list.
3878 Show the text at the center of the video frame:
3880 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
3884 Show a text line sliding from right to left in the last row of the video
3885 frame. The file @file{LONG_LINE} is assumed to contain a single line
3888 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
3892 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
3894 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
3898 Draw a single green letter "g", at the center of the input video.
3899 The glyph baseline is placed at half screen height.
3901 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
3905 Show text for 1 second every 3 seconds:
3907 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
3911 Use fontconfig to set the font. Note that the colons need to be escaped.
3913 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
3917 Print the date of a real-time encoding (see strftime(3)):
3919 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
3924 For more information about libfreetype, check:
3925 @url{http://www.freetype.org/}.
3927 For more information about fontconfig, check:
3928 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
3932 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
3934 The filter accepts the following options:
3939 Set low and high threshold values used by the Canny thresholding
3942 The high threshold selects the "strong" edge pixels, which are then
3943 connected through 8-connectivity with the "weak" edge pixels selected
3944 by the low threshold.
3946 @var{low} and @var{high} threshold values must be chosen in the range
3947 [0,1], and @var{low} should be lesser or equal to @var{high}.
3949 Default value for @var{low} is @code{20/255}, and default value for @var{high}
3955 edgedetect=low=0.1:high=0.4
3958 @section extractplanes
3960 Extract color channel components from input video stream into
3961 separate grayscale video streams.
3963 The filter accepts the following option:
3967 Set plane(s) to extract.
3969 Available values for planes are:
3980 Choosing planes not available in the input will result in an error.
3981 That means you cannot select @code{r}, @code{g}, @code{b} planes
3982 with @code{y}, @code{u}, @code{v} planes at same time.
3985 @subsection Examples
3989 Extract luma, u and v color channel component from input video frame
3990 into 3 grayscale outputs:
3992 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
3998 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4000 For each input image, the filter will compute the optimal mapping from
4001 the input to the output given the codebook length, that is the number
4002 of distinct output colors.
4004 This filter accepts the following options.
4007 @item codebook_length, l
4008 Set codebook length. The value must be a positive integer, and
4009 represents the number of distinct output colors. Default value is 256.
4012 Set the maximum number of iterations to apply for computing the optimal
4013 mapping. The higher the value the better the result and the higher the
4014 computation time. Default value is 1.
4017 Set a random seed, must be an integer included between 0 and
4018 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4019 will try to use a good random seed on a best effort basis.
4024 Apply fade-in/out effect to input video.
4026 This filter accepts the following options:
4030 The effect type -- can be either "in" for fade-in, or "out" for a fade-out
4032 Default is @code{in}.
4034 @item start_frame, s
4035 Specify the number of the start frame for starting to apply the fade
4036 effect. Default is 0.
4039 The number of frames for which the fade effect has to last. At the end of the
4040 fade-in effect the output video will have the same intensity as the input video,
4041 at the end of the fade-out transition the output video will be filled with the
4042 selected @option{color}.
4046 If set to 1, fade only alpha channel, if one exists on the input.
4049 @item start_time, st
4050 Specify the timestamp (in seconds) of the frame to start to apply the fade
4051 effect. If both start_frame and start_time are specified, the fade will start at
4052 whichever comes last. Default is 0.
4055 The number of seconds for which the fade effect has to last. At the end of the
4056 fade-in effect the output video will have the same intensity as the input video,
4057 at the end of the fade-out transition the output video will be filled with the
4058 selected @option{color}.
4059 If both duration and nb_frames are specified, duration is used. Default is 0.
4062 Specify the color of the fade. Default is "black".
4065 @subsection Examples
4069 Fade in first 30 frames of video:
4074 The command above is equivalent to:
4080 Fade out last 45 frames of a 200-frame video:
4083 fade=type=out:start_frame=155:nb_frames=45
4087 Fade in first 25 frames and fade out last 25 frames of a 1000-frame video:
4089 fade=in:0:25, fade=out:975:25
4093 Make first 5 frames yellow, then fade in from frame 5-24:
4095 fade=in:5:20:color=yellow
4099 Fade in alpha over first 25 frames of video:
4101 fade=in:0:25:alpha=1
4105 Make first 5.5 seconds black, then fade in for 0.5 seconds:
4107 fade=t=in:st=5.5:d=0.5
4114 Extract a single field from an interlaced image using stride
4115 arithmetic to avoid wasting CPU time. The output frames are marked as
4118 The filter accepts the following options:
4122 Specify whether to extract the top (if the value is @code{0} or
4123 @code{top}) or the bottom field (if the value is @code{1} or
4129 Field matching filter for inverse telecine. It is meant to reconstruct the
4130 progressive frames from a telecined stream. The filter does not drop duplicated
4131 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4132 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4134 The separation of the field matching and the decimation is notably motivated by
4135 the possibility of inserting a de-interlacing filter fallback between the two.
4136 If the source has mixed telecined and real interlaced content,
4137 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4138 But these remaining combed frames will be marked as interlaced, and thus can be
4139 de-interlaced by a later filter such as @ref{yadif} before decimation.
4141 In addition to the various configuration options, @code{fieldmatch} can take an
4142 optional second stream, activated through the @option{ppsrc} option. If
4143 enabled, the frames reconstruction will be based on the fields and frames from
4144 this second stream. This allows the first input to be pre-processed in order to
4145 help the various algorithms of the filter, while keeping the output lossless
4146 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4147 or brightness/contrast adjustments can help.
4149 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4150 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4151 which @code{fieldmatch} is based on. While the semantic and usage are very
4152 close, some behaviour and options names can differ.
4154 The filter accepts the following options:
4158 Specify the assumed field order of the input stream. Available values are:
4162 Auto detect parity (use FFmpeg's internal parity value).
4164 Assume bottom field first.
4166 Assume top field first.
4169 Note that it is sometimes recommended not to trust the parity announced by the
4172 Default value is @var{auto}.
4175 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4176 sense that it won't risk creating jerkiness due to duplicate frames when
4177 possible, but if there are bad edits or blended fields it will end up
4178 outputting combed frames when a good match might actually exist. On the other
4179 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4180 but will almost always find a good frame if there is one. The other values are
4181 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4182 jerkiness and creating duplicate frames versus finding good matches in sections
4183 with bad edits, orphaned fields, blended fields, etc.
4185 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4187 Available values are:
4191 2-way matching (p/c)
4193 2-way matching, and trying 3rd match if still combed (p/c + n)
4195 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4197 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4198 still combed (p/c + n + u/b)
4200 3-way matching (p/c/n)
4202 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4203 detected as combed (p/c/n + u/b)
4206 The parenthesis at the end indicate the matches that would be used for that
4207 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4210 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4213 Default value is @var{pc_n}.
4216 Mark the main input stream as a pre-processed input, and enable the secondary
4217 input stream as the clean source to pick the fields from. See the filter
4218 introduction for more details. It is similar to the @option{clip2} feature from
4221 Default value is @code{0} (disabled).
4224 Set the field to match from. It is recommended to set this to the same value as
4225 @option{order} unless you experience matching failures with that setting. In
4226 certain circumstances changing the field that is used to match from can have a
4227 large impact on matching performance. Available values are:
4231 Automatic (same value as @option{order}).
4233 Match from the bottom field.
4235 Match from the top field.
4238 Default value is @var{auto}.
4241 Set whether or not chroma is included during the match comparisons. In most
4242 cases it is recommended to leave this enabled. You should set this to @code{0}
4243 only if your clip has bad chroma problems such as heavy rainbowing or other
4244 artifacts. Setting this to @code{0} could also be used to speed things up at
4245 the cost of some accuracy.
4247 Default value is @code{1}.
4251 These define an exclusion band which excludes the lines between @option{y0} and
4252 @option{y1} from being included in the field matching decision. An exclusion
4253 band can be used to ignore subtitles, a logo, or other things that may
4254 interfere with the matching. @option{y0} sets the starting scan line and
4255 @option{y1} sets the ending line; all lines in between @option{y0} and
4256 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4257 @option{y0} and @option{y1} to the same value will disable the feature.
4258 @option{y0} and @option{y1} defaults to @code{0}.
4261 Set the scene change detection threshold as a percentage of maximum change on
4262 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4263 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4264 @option{scthresh} is @code{[0.0, 100.0]}.
4266 Default value is @code{12.0}.
4269 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4270 account the combed scores of matches when deciding what match to use as the
4271 final match. Available values are:
4275 No final matching based on combed scores.
4277 Combed scores are only used when a scene change is detected.
4279 Use combed scores all the time.
4282 Default is @var{sc}.
4285 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4286 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4287 Available values are:
4291 No forced calculation.
4293 Force p/c/n calculations.
4295 Force p/c/n/u/b calculations.
4298 Default value is @var{none}.
4301 This is the area combing threshold used for combed frame detection. This
4302 essentially controls how "strong" or "visible" combing must be to be detected.
4303 Larger values mean combing must be more visible and smaller values mean combing
4304 can be less visible or strong and still be detected. Valid settings are from
4305 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4306 be detected as combed). This is basically a pixel difference value. A good
4307 range is @code{[8, 12]}.
4309 Default value is @code{9}.
4312 Sets whether or not chroma is considered in the combed frame decision. Only
4313 disable this if your source has chroma problems (rainbowing, etc.) that are
4314 causing problems for the combed frame detection with chroma enabled. Actually,
4315 using @option{chroma}=@var{0} is usually more reliable, except for the case
4316 where there is chroma only combing in the source.
4318 Default value is @code{0}.
4322 Respectively set the x-axis and y-axis size of the window used during combed
4323 frame detection. This has to do with the size of the area in which
4324 @option{combpel} pixels are required to be detected as combed for a frame to be
4325 declared combed. See the @option{combpel} parameter description for more info.
4326 Possible values are any number that is a power of 2 starting at 4 and going up
4329 Default value is @code{16}.
4332 The number of combed pixels inside any of the @option{blocky} by
4333 @option{blockx} size blocks on the frame for the frame to be detected as
4334 combed. While @option{cthresh} controls how "visible" the combing must be, this
4335 setting controls "how much" combing there must be in any localized area (a
4336 window defined by the @option{blockx} and @option{blocky} settings) on the
4337 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4338 which point no frames will ever be detected as combed). This setting is known
4339 as @option{MI} in TFM/VFM vocabulary.
4341 Default value is @code{80}.
4344 @anchor{p/c/n/u/b meaning}
4345 @subsection p/c/n/u/b meaning
4347 @subsubsection p/c/n
4349 We assume the following telecined stream:
4352 Top fields: 1 2 2 3 4
4353 Bottom fields: 1 2 3 4 4
4356 The numbers correspond to the progressive frame the fields relate to. Here, the
4357 first two frames are progressive, the 3rd and 4th are combed, and so on.
4359 When @code{fieldmatch} is configured to run a matching from bottom
4360 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4365 B 1 2 3 4 4 <-- matching reference
4374 As a result of the field matching, we can see that some frames get duplicated.
4375 To perform a complete inverse telecine, you need to rely on a decimation filter
4376 after this operation. See for instance the @ref{decimate} filter.
4378 The same operation now matching from top fields (@option{field}=@var{top})
4383 T 1 2 2 3 4 <-- matching reference
4393 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4394 basically, they refer to the frame and field of the opposite parity:
4397 @item @var{p} matches the field of the opposite parity in the previous frame
4398 @item @var{c} matches the field of the opposite parity in the current frame
4399 @item @var{n} matches the field of the opposite parity in the next frame
4404 The @var{u} and @var{b} matching are a bit special in the sense that they match
4405 from the opposite parity flag. In the following examples, we assume that we are
4406 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4407 'x' is placed above and below each matched fields.
4409 With bottom matching (@option{field}=@var{bottom}):
4414 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4415 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4423 With top matching (@option{field}=@var{top}):
4428 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4429 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4437 @subsection Examples
4439 Simple IVTC of a top field first telecined stream:
4441 fieldmatch=order=tff:combmatch=none, decimate
4444 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4446 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4451 Transform the field order of the input video.
4453 This filter accepts the following options:
4458 Output field order. Valid values are @var{tff} for top field first or @var{bff}
4459 for bottom field first.
4462 Default value is @samp{tff}.
4464 Transformation is achieved by shifting the picture content up or down
4465 by one line, and filling the remaining line with appropriate picture content.
4466 This method is consistent with most broadcast field order converters.
4468 If the input video is not flagged as being interlaced, or it is already
4469 flagged as being of the required output field order then this filter does
4470 not alter the incoming video.
4472 This filter is very useful when converting to or from PAL DV material,
4473 which is bottom field first.
4477 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4482 Buffer input images and send them when they are requested.
4484 This filter is mainly useful when auto-inserted by the libavfilter
4487 The filter does not take parameters.
4492 Convert the input video to one of the specified pixel formats.
4493 Libavfilter will try to pick one that is supported for the input to
4496 This filter accepts the following parameters:
4500 A '|'-separated list of pixel format names, for example
4501 "pix_fmts=yuv420p|monow|rgb24".
4505 @subsection Examples
4509 Convert the input video to the format @var{yuv420p}
4511 format=pix_fmts=yuv420p
4514 Convert the input video to any of the formats in the list
4516 format=pix_fmts=yuv420p|yuv444p|yuv410p
4523 Convert the video to specified constant frame rate by duplicating or dropping
4524 frames as necessary.
4526 This filter accepts the following named parameters:
4530 Desired output frame rate. The default is @code{25}.
4535 Possible values are:
4538 zero round towards 0
4542 round towards -infinity
4544 round towards +infinity
4548 The default is @code{near}.
4551 Assume the first PTS should be the given value, in seconds. This allows for
4552 padding/trimming at the start of stream. By default, no assumption is made
4553 about the first frame's expected PTS, so no padding or trimming is done.
4554 For example, this could be set to 0 to pad the beginning with duplicates of
4555 the first frame if a video stream starts after the audio stream or to trim any
4556 frames with a negative PTS.
4560 Alternatively, the options can be specified as a flat string:
4561 @var{fps}[:@var{round}].
4563 See also the @ref{setpts} filter.
4565 @subsection Examples
4569 A typical usage in order to set the fps to 25:
4575 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4577 fps=fps=film:round=near
4583 Pack two different video streams into a stereoscopic video, setting proper
4584 metadata on supported codecs. The two views should have the same size and
4585 framerate and processing will stop when the shorter video ends. Please note
4586 that you may conveniently adjust view properties with the @ref{scale} and
4589 This filter accepts the following named parameters:
4593 Desired packing format. Supported values are:
4598 Views are next to each other (default).
4601 Views are on top of each other.
4604 Views are packed by line.
4607 Views are eacked by column.
4610 Views are temporally interleaved.
4616 Some examples follow:
4619 # Convert left and right views into a frame sequential video.
4620 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
4622 # Convert views into a side-by-side video with the same output resolution as the input.
4623 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
4628 Select one frame every N-th frame.
4630 This filter accepts the following option:
4633 Select frame after every @code{step} frames.
4634 Allowed values are positive integers higher than 0. Default value is @code{1}.
4640 Apply a frei0r effect to the input video.
4642 To enable compilation of this filter you need to install the frei0r
4643 header and configure FFmpeg with @code{--enable-frei0r}.
4645 This filter accepts the following options:
4650 The name to the frei0r effect to load. If the environment variable
4651 @env{FREI0R_PATH} is defined, the frei0r effect is searched in each one of the
4652 directories specified by the colon separated list in @env{FREIOR_PATH},
4653 otherwise in the standard frei0r paths, which are in this order:
4654 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
4655 @file{/usr/lib/frei0r-1/}.
4658 A '|'-separated list of parameters to pass to the frei0r effect.
4662 A frei0r effect parameter can be a boolean (whose values are specified
4663 with "y" and "n"), a double, a color (specified by the syntax
4664 @var{R}/@var{G}/@var{B}, (@var{R}, @var{G}, and @var{B} being float
4665 numbers from 0.0 to 1.0) or by a color description specified in the "Color"
4666 section in the ffmpeg-utils manual), a position (specified by the syntax @var{X}/@var{Y},
4667 @var{X} and @var{Y} being float numbers) and a string.
4669 The number and kind of parameters depend on the loaded effect. If an
4670 effect parameter is not specified the default value is set.
4672 @subsection Examples
4676 Apply the distort0r effect, set the first two double parameters:
4678 frei0r=filter_name=distort0r:filter_params=0.5|0.01
4682 Apply the colordistance effect, take a color as first parameter:
4684 frei0r=colordistance:0.2/0.3/0.4
4685 frei0r=colordistance:violet
4686 frei0r=colordistance:0x112233
4690 Apply the perspective effect, specify the top left and top right image
4693 frei0r=perspective:0.2/0.2|0.8/0.2
4697 For more information see:
4698 @url{http://frei0r.dyne.org}
4702 The filter accepts the following options:
4706 Set the luminance expression.
4708 Set the chrominance blue expression.
4710 Set the chrominance red expression.
4712 Set the alpha expression.
4714 Set the red expression.
4716 Set the green expression.
4718 Set the blue expression.
4721 The colorspace is selected according to the specified options. If one
4722 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4723 options is specified, the filter will automatically select a YCbCr
4724 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4725 @option{blue_expr} options is specified, it will select an RGB
4728 If one of the chrominance expression is not defined, it falls back on the other
4729 one. If no alpha expression is specified it will evaluate to opaque value.
4730 If none of chrominance expressions are specified, they will evaluate
4731 to the luminance expression.
4733 The expressions can use the following variables and functions:
4737 The sequential number of the filtered frame, starting from @code{0}.
4741 The coordinates of the current sample.
4745 The width and height of the image.
4749 Width and height scale depending on the currently filtered plane. It is the
4750 ratio between the corresponding luma plane number of pixels and the current
4751 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4752 @code{0.5,0.5} for chroma planes.
4755 Time of the current frame, expressed in seconds.
4758 Return the value of the pixel at location (@var{x},@var{y}) of the current
4762 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
4766 Return the value of the pixel at location (@var{x},@var{y}) of the
4767 blue-difference chroma plane. Return 0 if there is no such plane.
4770 Return the value of the pixel at location (@var{x},@var{y}) of the
4771 red-difference chroma plane. Return 0 if there is no such plane.
4776 Return the value of the pixel at location (@var{x},@var{y}) of the
4777 red/green/blue component. Return 0 if there is no such component.
4780 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
4781 plane. Return 0 if there is no such plane.
4784 For functions, if @var{x} and @var{y} are outside the area, the value will be
4785 automatically clipped to the closer edge.
4787 @subsection Examples
4791 Flip the image horizontally:
4797 Generate a bidimensional sine wave, with angle @code{PI/3} and a
4798 wavelength of 100 pixels:
4800 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
4804 Generate a fancy enigmatic moving light:
4806 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
4810 Generate a quick emboss effect:
4812 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
4816 Modify RGB components depending on pixel position:
4818 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
4824 Fix the banding artifacts that are sometimes introduced into nearly flat
4825 regions by truncation to 8bit color depth.
4826 Interpolate the gradients that should go where the bands are, and
4829 This filter is designed for playback only. Do not use it prior to
4830 lossy compression, because compression tends to lose the dither and
4831 bring back the bands.
4833 This filter accepts the following options:
4838 The maximum amount by which the filter will change any one pixel. Also the
4839 threshold for detecting nearly flat regions. Acceptable values range from .51 to
4840 64, default value is 1.2, out-of-range values will be clipped to the valid
4844 The neighborhood to fit the gradient to. A larger radius makes for smoother
4845 gradients, but also prevents the filter from modifying the pixels near detailed
4846 regions. Acceptable values are 8-32, default value is 16, out-of-range values
4847 will be clipped to the valid range.
4851 Alternatively, the options can be specified as a flat string:
4852 @var{strength}[:@var{radius}]
4854 @subsection Examples
4858 Apply the filter with a @code{3.5} strength and radius of @code{8}:
4864 Specify radius, omitting the strength (which will fall-back to the default
4875 Apply a Hald CLUT to a video stream.
4877 First input is the video stream to process, and second one is the Hald CLUT.
4878 The Hald CLUT input can be a simple picture or a complete video stream.
4880 The filter accepts the following options:
4884 Force termination when the shortest input terminates. Default is @code{0}.
4886 Continue applying the last CLUT after the end of the stream. A value of
4887 @code{0} disable the filter after the last frame of the CLUT is reached.
4888 Default is @code{1}.
4891 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
4892 filters share the same internals).
4894 More information about the Hald CLUT can be found on Eskil Steenberg's website
4895 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
4897 @subsection Workflow examples
4899 @subsubsection Hald CLUT video stream
4901 Generate an identity Hald CLUT stream altered with various effects:
4903 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
4906 Note: make sure you use a lossless codec.
4908 Then use it with @code{haldclut} to apply it on some random stream:
4910 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
4913 The Hald CLUT will be applied to the 10 first seconds (duration of
4914 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
4915 to the remaining frames of the @code{mandelbrot} stream.
4917 @subsubsection Hald CLUT with preview
4919 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
4920 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
4921 biggest possible square starting at the top left of the picture. The remaining
4922 padding pixels (bottom or right) will be ignored. This area can be used to add
4923 a preview of the Hald CLUT.
4925 Typically, the following generated Hald CLUT will be supported by the
4926 @code{haldclut} filter:
4929 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
4930 pad=iw+320 [padded_clut];
4931 smptebars=s=320x256, split [a][b];
4932 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
4933 [main][b] overlay=W-320" -frames:v 1 clut.png
4936 It contains the original and a preview of the effect of the CLUT: SMPTE color
4937 bars are displayed on the right-top, and below the same color bars processed by
4940 Then, the effect of this Hald CLUT can be visualized with:
4942 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
4947 Flip the input video horizontally.
4949 For example to horizontally flip the input video with @command{ffmpeg}:
4951 ffmpeg -i in.avi -vf "hflip" out.avi
4955 This filter applies a global color histogram equalization on a
4958 It can be used to correct video that has a compressed range of pixel
4959 intensities. The filter redistributes the pixel intensities to
4960 equalize their distribution across the intensity range. It may be
4961 viewed as an "automatically adjusting contrast filter". This filter is
4962 useful only for correcting degraded or poorly captured source
4965 The filter accepts the following options:
4969 Determine the amount of equalization to be applied. As the strength
4970 is reduced, the distribution of pixel intensities more-and-more
4971 approaches that of the input frame. The value must be a float number
4972 in the range [0,1] and defaults to 0.200.
4975 Set the maximum intensity that can generated and scale the output
4976 values appropriately. The strength should be set as desired and then
4977 the intensity can be limited if needed to avoid washing-out. The value
4978 must be a float number in the range [0,1] and defaults to 0.210.
4981 Set the antibanding level. If enabled the filter will randomly vary
4982 the luminance of output pixels by a small amount to avoid banding of
4983 the histogram. Possible values are @code{none}, @code{weak} or
4984 @code{strong}. It defaults to @code{none}.
4989 Compute and draw a color distribution histogram for the input video.
4991 The computed histogram is a representation of the color component
4992 distribution in an image.
4994 The filter accepts the following options:
5000 It accepts the following values:
5003 Standard histogram that displays the color components distribution in an
5004 image. Displays color graph for each color component. Shows distribution of
5005 the Y, U, V, A or R, G, B components, depending on input format, in the
5006 current frame. Below each graph a color component scale meter is shown.
5009 Displays chroma values (U/V color placement) in a two dimensional
5010 graph (which is called a vectorscope). The brighter a pixel in the
5011 vectorscope, the more pixels of the input frame correspond to that pixel
5012 (i.e., more pixels have this chroma value). The V component is displayed on
5013 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5014 side being V = 255. The U component is displayed on the vertical (Y) axis,
5015 with the top representing U = 0 and the bottom representing U = 255.
5017 The position of a white pixel in the graph corresponds to the chroma value of
5018 a pixel of the input clip. The graph can therefore be used to read the hue
5019 (color flavor) and the saturation (the dominance of the hue in the color). As
5020 the hue of a color changes, it moves around the square. At the center of the
5021 square the saturation is zero, which means that the corresponding pixel has no
5022 color. If the amount of a specific color is increased (while leaving the other
5023 colors unchanged) the saturation increases, and the indicator moves towards
5024 the edge of the square.
5027 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5031 Per row/column color component graph. In row mode, the graph on the left side
5032 represents color component value 0 and the right side represents value = 255.
5033 In column mode, the top side represents color component value = 0 and bottom
5034 side represents value = 255.
5036 Default value is @code{levels}.
5039 Set height of level in @code{levels}. Default value is @code{200}.
5040 Allowed range is [50, 2048].
5043 Set height of color scale in @code{levels}. Default value is @code{12}.
5044 Allowed range is [0, 40].
5047 Set step for @code{waveform} mode. Smaller values are useful to find out how
5048 many values of the same luminance are distributed across input rows/columns.
5049 Default value is @code{10}. Allowed range is [1, 255].
5052 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5053 Default is @code{row}.
5055 @item waveform_mirror
5056 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5057 means mirrored. In mirrored mode, higher values will be represented on the left
5058 side for @code{row} mode and at the top for @code{column} mode. Default is
5059 @code{0} (unmirrored).
5062 Set display mode for @code{waveform} and @code{levels}.
5063 It accepts the following values:
5066 Display separate graph for the color components side by side in
5067 @code{row} waveform mode or one below the other in @code{column} waveform mode
5068 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5069 per color component graphs are placed below each other.
5071 Using this display mode in @code{waveform} histogram mode makes it easy to
5072 spot color casts in the highlights and shadows of an image, by comparing the
5073 contours of the top and the bottom graphs of each waveform. Since whites,
5074 grays, and blacks are characterized by exactly equal amounts of red, green,
5075 and blue, neutral areas of the picture should display three waveforms of
5076 roughly equal width/height. If not, the correction is easy to perform by
5077 making level adjustments the three waveforms.
5080 Presents information identical to that in the @code{parade}, except
5081 that the graphs representing color components are superimposed directly
5084 This display mode in @code{waveform} histogram mode makes it easier to spot
5085 relative differences or similarities in overlapping areas of the color
5086 components that are supposed to be identical, such as neutral whites, grays,
5089 Default is @code{parade}.
5092 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5093 Default is @code{linear}.
5096 @subsection Examples
5101 Calculate and draw histogram:
5103 ffplay -i input -vf histogram
5111 High precision/quality 3d denoise filter. This filter aims to reduce
5112 image noise producing smooth images and making still images really
5113 still. It should enhance compressibility.
5115 It accepts the following optional parameters:
5119 a non-negative float number which specifies spatial luma strength,
5122 @item chroma_spatial
5123 a non-negative float number which specifies spatial chroma strength,
5124 defaults to 3.0*@var{luma_spatial}/4.0
5127 a float number which specifies luma temporal strength, defaults to
5128 6.0*@var{luma_spatial}/4.0
5131 a float number which specifies chroma temporal strength, defaults to
5132 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
5137 Modify the hue and/or the saturation of the input.
5139 This filter accepts the following options:
5143 Specify the hue angle as a number of degrees. It accepts an expression,
5144 and defaults to "0".
5147 Specify the saturation in the [-10,10] range. It accepts an expression and
5151 Specify the hue angle as a number of radians. It accepts an
5152 expression, and defaults to "0".
5155 Specify the brightness in the [-10,10] range. It accepts an expression and
5159 @option{h} and @option{H} are mutually exclusive, and can't be
5160 specified at the same time.
5162 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5163 expressions containing the following constants:
5167 frame count of the input frame starting from 0
5170 presentation timestamp of the input frame expressed in time base units
5173 frame rate of the input video, NAN if the input frame rate is unknown
5176 timestamp expressed in seconds, NAN if the input timestamp is unknown
5179 time base of the input video
5182 @subsection Examples
5186 Set the hue to 90 degrees and the saturation to 1.0:
5192 Same command but expressing the hue in radians:
5198 Rotate hue and make the saturation swing between 0
5199 and 2 over a period of 1 second:
5201 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5205 Apply a 3 seconds saturation fade-in effect starting at 0:
5210 The general fade-in expression can be written as:
5212 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5216 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5218 hue="s=max(0\, min(1\, (8-t)/3))"
5221 The general fade-out expression can be written as:
5223 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5228 @subsection Commands
5230 This filter supports the following commands:
5236 Modify the hue and/or the saturation and/or brightness of the input video.
5237 The command accepts the same syntax of the corresponding option.
5239 If the specified expression is not valid, it is kept at its current
5245 Detect video interlacing type.
5247 This filter tries to detect if the input is interlaced or progressive,
5248 top or bottom field first.
5250 The filter accepts the following options:
5254 Set interlacing threshold.
5256 Set progressive threshold.
5261 Deinterleave or interleave fields.
5263 This filter allows one to process interlaced images fields without
5264 deinterlacing them. Deinterleaving splits the input frame into 2
5265 fields (so called half pictures). Odd lines are moved to the top
5266 half of the output image, even lines to the bottom half.
5267 You can process (filter) them independently and then re-interleave them.
5269 The filter accepts the following options:
5273 @item chroma_mode, c
5275 Available values for @var{luma_mode}, @var{chroma_mode} and
5276 @var{alpha_mode} are:
5282 @item deinterleave, d
5283 Deinterleave fields, placing one above the other.
5286 Interleave fields. Reverse the effect of deinterleaving.
5288 Default value is @code{none}.
5291 @item chroma_swap, cs
5292 @item alpha_swap, as
5293 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5298 Simple interlacing filter from progressive contents. This interleaves upper (or
5299 lower) lines from odd frames with lower (or upper) lines from even frames,
5300 halving the frame rate and preserving image height. A vertical lowpass filter
5301 is always applied in order to avoid twitter effects and reduce moiré patterns.
5304 Original Original New Frame
5305 Frame 'j' Frame 'j+1' (tff)
5306 ========== =========== ==================
5307 Line 0 --------------------> Frame 'j' Line 0
5308 Line 1 Line 1 ----> Frame 'j+1' Line 1
5309 Line 2 ---------------------> Frame 'j' Line 2
5310 Line 3 Line 3 ----> Frame 'j+1' Line 3
5312 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5315 It accepts the following optional parameters:
5319 determines whether the interlaced frame is taken from the even (tff - default)
5320 or odd (bff) lines of the progressive frame.
5325 Deinterlace input video by applying Donald Graft's adaptive kernel
5326 deinterling. Work on interlaced parts of a video to produce
5329 The description of the accepted parameters follows.
5333 Set the threshold which affects the filter's tolerance when
5334 determining if a pixel line must be processed. It must be an integer
5335 in the range [0,255] and defaults to 10. A value of 0 will result in
5336 applying the process on every pixels.
5339 Paint pixels exceeding the threshold value to white if set to 1.
5343 Set the fields order. Swap fields if set to 1, leave fields alone if
5347 Enable additional sharpening if set to 1. Default is 0.
5350 Enable twoway sharpening if set to 1. Default is 0.
5353 @subsection Examples
5357 Apply default values:
5359 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5363 Enable additional sharpening:
5369 Paint processed pixels in white:
5378 Apply a 3D LUT to an input video.
5380 The filter accepts the following options:
5384 Set the 3D LUT file name.
5386 Currently supported formats:
5398 Select interpolation mode.
5400 Available values are:
5404 Use values from the nearest defined point.
5406 Interpolate values using the 8 points defining a cube.
5408 Interpolate values using a tetrahedron.
5412 @section lut, lutrgb, lutyuv
5414 Compute a look-up table for binding each pixel component input value
5415 to an output value, and apply it to input video.
5417 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5418 to an RGB input video.
5420 These filters accept the following options:
5423 set first pixel component expression
5425 set second pixel component expression
5427 set third pixel component expression
5429 set fourth pixel component expression, corresponds to the alpha component
5432 set red component expression
5434 set green component expression
5436 set blue component expression
5438 alpha component expression
5441 set Y/luminance component expression
5443 set U/Cb component expression
5445 set V/Cr component expression
5448 Each of them specifies the expression to use for computing the lookup table for
5449 the corresponding pixel component values.
5451 The exact component associated to each of the @var{c*} options depends on the
5454 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5455 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5457 The expressions can contain the following constants and functions:
5462 the input width and height
5465 input value for the pixel component
5468 the input value clipped in the @var{minval}-@var{maxval} range
5471 maximum value for the pixel component
5474 minimum value for the pixel component
5477 the negated value for the pixel component value clipped in the
5478 @var{minval}-@var{maxval} range , it corresponds to the expression
5479 "maxval-clipval+minval"
5482 the computed value in @var{val} clipped in the
5483 @var{minval}-@var{maxval} range
5485 @item gammaval(gamma)
5486 the computed gamma correction value of the pixel component value
5487 clipped in the @var{minval}-@var{maxval} range, corresponds to the
5489 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
5493 All expressions default to "val".
5495 @subsection Examples
5501 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
5502 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
5505 The above is the same as:
5507 lutrgb="r=negval:g=negval:b=negval"
5508 lutyuv="y=negval:u=negval:v=negval"
5518 Remove chroma components, turns the video into a graytone image:
5520 lutyuv="u=128:v=128"
5524 Apply a luma burning effect:
5530 Remove green and blue components:
5536 Set a constant alpha channel value on input:
5538 format=rgba,lutrgb=a="maxval-minval/2"
5542 Correct luminance gamma by a 0.5 factor:
5544 lutyuv=y=gammaval(0.5)
5548 Discard least significant bits of luma:
5550 lutyuv=y='bitand(val, 128+64+32)'
5554 @section mergeplanes
5556 Merge color channel components from several video streams.
5558 The filter accepts up to 4 input streams, and merge selected input
5559 planes to the output video.
5561 This filter accepts the following options:
5564 Set input to output plane mapping. Default is @code{0}.
5566 The mappings is specified as a bitmap. It should be specified as a
5567 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
5568 mapping for the first plane of the output stream. 'A' sets the number of
5569 the input stream to use (from 0 to 3), and 'a' the plane number of the
5570 corresponding input to use (from 0 to 3). The rest of the mappings is
5571 similar, 'Bb' describes the mapping for the output stream second
5572 plane, 'Cc' describes the mapping for the output stream third plane and
5573 'Dd' describes the mapping for the output stream fourth plane.
5576 Set output pixel format. Default is @code{yuva444p}.
5579 @subsection Examples
5583 Merge three gray video streams of same width and height into single video stream:
5585 [a0][a1][a2]mergeplanes=0x001020:yuv444p
5589 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
5591 [a0][a1]mergeplanes=0x00010210:yuva444p
5595 Swap Y and A plane in yuva444p stream:
5597 format=yuva444p,mergeplanes=0x03010200:yuva444p
5601 Swap U and V plane in yuv420p stream:
5603 format=yuv420p,mergeplanes=0x000201:yuv420p
5607 Cast a rgb24 clip to yuv444p:
5609 format=rgb24,mergeplanes=0x000102:yuv444p
5615 Apply motion-compensation deinterlacing.
5617 It needs one field per frame as input and must thus be used together
5618 with yadif=1/3 or equivalent.
5620 This filter accepts the following options:
5623 Set the deinterlacing mode.
5625 It accepts one of the following values:
5630 use iterative motion estimation
5632 like @samp{slow}, but use multiple reference frames.
5634 Default value is @samp{fast}.
5637 Set the picture field parity assumed for the input video. It must be
5638 one of the following values:
5642 assume top field first
5644 assume bottom field first
5647 Default value is @samp{bff}.
5650 Set per-block quantization parameter (QP) used by the internal
5653 Higher values should result in a smoother motion vector field but less
5654 optimal individual vectors. Default value is 1.
5659 Apply an MPlayer filter to the input video.
5661 This filter provides a wrapper around some of the filters of
5664 This wrapper is considered experimental. Some of the wrapped filters
5665 may not work properly and we may drop support for them, as they will
5666 be implemented natively into FFmpeg. Thus you should avoid
5667 depending on them when writing portable scripts.
5669 The filter accepts the parameters:
5670 @var{filter_name}[:=]@var{filter_params}
5672 @var{filter_name} is the name of a supported MPlayer filter,
5673 @var{filter_params} is a string containing the parameters accepted by
5676 The list of the currently supported filters follows:
5687 The parameter syntax and behavior for the listed filters are the same
5688 of the corresponding MPlayer filters. For detailed instructions check
5689 the "VIDEO FILTERS" section in the MPlayer manual.
5691 @subsection Examples
5695 Adjust gamma, brightness, contrast:
5701 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
5705 Drop frames that do not differ greatly from the previous frame in
5706 order to reduce frame rate.
5708 The main use of this filter is for very-low-bitrate encoding
5709 (e.g. streaming over dialup modem), but it could in theory be used for
5710 fixing movies that were inverse-telecined incorrectly.
5712 A description of the accepted options follows.
5716 Set the maximum number of consecutive frames which can be dropped (if
5717 positive), or the minimum interval between dropped frames (if
5718 negative). If the value is 0, the frame is dropped unregarding the
5719 number of previous sequentially dropped frames.
5726 Set the dropping threshold values.
5728 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
5729 represent actual pixel value differences, so a threshold of 64
5730 corresponds to 1 unit of difference for each pixel, or the same spread
5731 out differently over the block.
5733 A frame is a candidate for dropping if no 8x8 blocks differ by more
5734 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
5735 meaning the whole image) differ by more than a threshold of @option{lo}.
5737 Default value for @option{hi} is 64*12, default value for @option{lo} is
5738 64*5, and default value for @option{frac} is 0.33.
5746 This filter accepts an integer in input, if non-zero it negates the
5747 alpha component (if available). The default value in input is 0.
5751 Force libavfilter not to use any of the specified pixel formats for the
5752 input to the next filter.
5754 This filter accepts the following parameters:
5758 A '|'-separated list of pixel format names, for example
5759 "pix_fmts=yuv420p|monow|rgb24".
5763 @subsection Examples
5767 Force libavfilter to use a format different from @var{yuv420p} for the
5768 input to the vflip filter:
5770 noformat=pix_fmts=yuv420p,vflip
5774 Convert the input video to any of the formats not contained in the list:
5776 noformat=yuv420p|yuv444p|yuv410p
5782 Add noise on video input frame.
5784 The filter accepts the following options:
5792 Set noise seed for specific pixel component or all pixel components in case
5793 of @var{all_seed}. Default value is @code{123457}.
5795 @item all_strength, alls
5796 @item c0_strength, c0s
5797 @item c1_strength, c1s
5798 @item c2_strength, c2s
5799 @item c3_strength, c3s
5800 Set noise strength for specific pixel component or all pixel components in case
5801 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
5803 @item all_flags, allf
5808 Set pixel component flags or set flags for all components if @var{all_flags}.
5809 Available values for component flags are:
5812 averaged temporal noise (smoother)
5814 mix random noise with a (semi)regular pattern
5816 temporal noise (noise pattern changes between frames)
5818 uniform noise (gaussian otherwise)
5822 @subsection Examples
5824 Add temporal and uniform noise to input video:
5826 noise=alls=20:allf=t+u
5831 Pass the video source unchanged to the output.
5835 Apply video transform using libopencv.
5837 To enable this filter install libopencv library and headers and
5838 configure FFmpeg with @code{--enable-libopencv}.
5840 This filter accepts the following parameters:
5845 The name of the libopencv filter to apply.
5848 The parameters to pass to the libopencv filter. If not specified the default
5853 Refer to the official libopencv documentation for more precise
5855 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
5857 Follows the list of supported libopencv filters.
5862 Dilate an image by using a specific structuring element.
5863 This filter corresponds to the libopencv function @code{cvDilate}.
5865 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
5867 @var{struct_el} represents a structuring element, and has the syntax:
5868 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
5870 @var{cols} and @var{rows} represent the number of columns and rows of
5871 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
5872 point, and @var{shape} the shape for the structuring element, and
5873 can be one of the values "rect", "cross", "ellipse", "custom".
5875 If the value for @var{shape} is "custom", it must be followed by a
5876 string of the form "=@var{filename}". The file with name
5877 @var{filename} is assumed to represent a binary image, with each
5878 printable character corresponding to a bright pixel. When a custom
5879 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
5880 or columns and rows of the read file are assumed instead.
5882 The default value for @var{struct_el} is "3x3+0x0/rect".
5884 @var{nb_iterations} specifies the number of times the transform is
5885 applied to the image, and defaults to 1.
5887 Follow some example:
5889 # use the default values
5892 # dilate using a structuring element with a 5x5 cross, iterate two times
5893 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
5895 # read the shape from the file diamond.shape, iterate two times
5896 # the file diamond.shape may contain a pattern of characters like this:
5902 # the specified cols and rows are ignored (but not the anchor point coordinates)
5903 ocv=dilate:0x0+2x2/custom=diamond.shape|2
5908 Erode an image by using a specific structuring element.
5909 This filter corresponds to the libopencv function @code{cvErode}.
5911 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
5912 with the same syntax and semantics as the @ref{dilate} filter.
5916 Smooth the input video.
5918 The filter takes the following parameters:
5919 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
5921 @var{type} is the type of smooth filter to apply, and can be one of
5922 the following values: "blur", "blur_no_scale", "median", "gaussian",
5923 "bilateral". The default value is "gaussian".
5925 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
5926 parameters whose meanings depend on smooth type. @var{param1} and
5927 @var{param2} accept integer positive values or 0, @var{param3} and
5928 @var{param4} accept float values.
5930 The default value for @var{param1} is 3, the default value for the
5931 other parameters is 0.
5933 These parameters correspond to the parameters assigned to the
5934 libopencv function @code{cvSmooth}.
5939 Overlay one video on top of another.
5941 It takes two inputs and one output, the first input is the "main"
5942 video on which the second input is overlayed.
5944 This filter accepts the following parameters:
5946 A description of the accepted options follows.
5951 Set the expression for the x and y coordinates of the overlayed video
5952 on the main video. Default value is "0" for both expressions. In case
5953 the expression is invalid, it is set to a huge value (meaning that the
5954 overlay will not be displayed within the output visible area).
5957 The action to take when EOF is encountered on the secondary input, accepts one
5958 of the following values:
5962 repeat the last frame (the default)
5966 pass through the main input
5970 Set when the expressions for @option{x}, and @option{y} are evaluated.
5972 It accepts the following values:
5975 only evaluate expressions once during the filter initialization or
5976 when a command is processed
5979 evaluate expressions for each incoming frame
5982 Default value is @samp{frame}.
5985 If set to 1, force the output to terminate when the shortest input
5986 terminates. Default value is 0.
5989 Set the format for the output video.
5991 It accepts the following values:
6006 Default value is @samp{yuv420}.
6008 @item rgb @emph{(deprecated)}
6009 If set to 1, force the filter to accept inputs in the RGB
6010 color space. Default value is 0. This option is deprecated, use
6011 @option{format} instead.
6014 If set to 1, force the filter to draw the last overlay frame over the
6015 main input until the end of the stream. A value of 0 disables this
6016 behavior. Default value is 1.
6019 The @option{x}, and @option{y} expressions can contain the following
6025 main input width and height
6029 overlay input width and height
6033 the computed values for @var{x} and @var{y}. They are evaluated for
6038 horizontal and vertical chroma subsample values of the output
6039 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6043 the number of input frame, starting from 0
6046 the position in the file of the input frame, NAN if unknown
6049 timestamp expressed in seconds, NAN if the input timestamp is unknown
6053 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6054 when evaluation is done @emph{per frame}, and will evaluate to NAN
6055 when @option{eval} is set to @samp{init}.
6057 Be aware that frames are taken from each input video in timestamp
6058 order, hence, if their initial timestamps differ, it is a good idea
6059 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6060 have them begin in the same zero timestamp, as it does the example for
6061 the @var{movie} filter.
6063 You can chain together more overlays but you should test the
6064 efficiency of such approach.
6066 @subsection Commands
6068 This filter supports the following commands:
6072 Modify the x and y of the overlay input.
6073 The command accepts the same syntax of the corresponding option.
6075 If the specified expression is not valid, it is kept at its current
6079 @subsection Examples
6083 Draw the overlay at 10 pixels from the bottom right corner of the main
6086 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6089 Using named options the example above becomes:
6091 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6095 Insert a transparent PNG logo in the bottom left corner of the input,
6096 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6098 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6102 Insert 2 different transparent PNG logos (second logo on bottom
6103 right corner) using the @command{ffmpeg} tool:
6105 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
6109 Add a transparent color layer on top of the main video, @code{WxH}
6110 must specify the size of the main input to the overlay filter:
6112 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6116 Play an original video and a filtered version (here with the deshake
6117 filter) side by side using the @command{ffplay} tool:
6119 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6122 The above command is the same as:
6124 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6128 Make a sliding overlay appearing from the left to the right top part of the
6129 screen starting since time 2:
6131 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6135 Compose output by putting two input videos side to side:
6137 ffmpeg -i left.avi -i right.avi -filter_complex "
6138 nullsrc=size=200x100 [background];
6139 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6140 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6141 [background][left] overlay=shortest=1 [background+left];
6142 [background+left][right] overlay=shortest=1:x=100 [left+right]
6147 mask 10-20 seconds of a video by applying the delogo filter to a section
6149 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6150 -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]'
6155 Chain several overlays in cascade:
6157 nullsrc=s=200x200 [bg];
6158 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6159 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6160 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6161 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6162 [in3] null, [mid2] overlay=100:100 [out0]
6169 Apply Overcomplete Wavelet denoiser.
6171 The filter accepts the following options:
6177 Larger depth values will denoise lower frequency components more, but
6178 slow down filtering.
6180 Must be an int in the range 8-16, default is @code{8}.
6182 @item luma_strength, ls
6185 Must be a double value in the range 0-1000, default is @code{1.0}.
6187 @item chroma_strength, cs
6188 Set chroma strength.
6190 Must be a double value in the range 0-1000, default is @code{1.0}.
6195 Add paddings to the input image, and place the original input at the
6196 given coordinates @var{x}, @var{y}.
6198 This filter accepts the following parameters:
6203 Specify an expression for the size of the output image with the
6204 paddings added. If the value for @var{width} or @var{height} is 0, the
6205 corresponding input size is used for the output.
6207 The @var{width} expression can reference the value set by the
6208 @var{height} expression, and vice versa.
6210 The default value of @var{width} and @var{height} is 0.
6214 Specify an expression for the offsets where to place the input image
6215 in the padded area with respect to the top/left border of the output
6218 The @var{x} expression can reference the value set by the @var{y}
6219 expression, and vice versa.
6221 The default value of @var{x} and @var{y} is 0.
6224 Specify the color of the padded area. For the syntax of this option,
6225 check the "Color" section in the ffmpeg-utils manual.
6227 The default value of @var{color} is "black".
6230 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6231 options are expressions containing the following constants:
6236 the input video width and height
6240 same as @var{in_w} and @var{in_h}
6244 the output width and height, that is the size of the padded area as
6245 specified by the @var{width} and @var{height} expressions
6249 same as @var{out_w} and @var{out_h}
6253 x and y offsets as specified by the @var{x} and @var{y}
6254 expressions, or NAN if not yet specified
6257 same as @var{iw} / @var{ih}
6260 input sample aspect ratio
6263 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6267 horizontal and vertical chroma subsample values. For example for the
6268 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6271 @subsection Examples
6275 Add paddings with color "violet" to the input video. Output video
6276 size is 640x480, the top-left corner of the input video is placed at
6279 pad=640:480:0:40:violet
6282 The example above is equivalent to the following command:
6284 pad=width=640:height=480:x=0:y=40:color=violet
6288 Pad the input to get an output with dimensions increased by 3/2,
6289 and put the input video at the center of the padded area:
6291 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6295 Pad the input to get a squared output with size equal to the maximum
6296 value between the input width and height, and put the input video at
6297 the center of the padded area:
6299 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6303 Pad the input to get a final w/h ratio of 16:9:
6305 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6309 In case of anamorphic video, in order to set the output display aspect
6310 correctly, it is necessary to use @var{sar} in the expression,
6311 according to the relation:
6313 (ih * X / ih) * sar = output_dar
6314 X = output_dar / sar
6317 Thus the previous example needs to be modified to:
6319 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6323 Double output size and put the input video in the bottom-right
6324 corner of the output padded area:
6326 pad="2*iw:2*ih:ow-iw:oh-ih"
6330 @section perspective
6332 Correct perspective of video not recorded perpendicular to the screen.
6334 A description of the accepted parameters follows.
6345 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6346 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6348 The expressions can use the following variables:
6353 the width and height of video frame.
6357 Set interpolation for perspective correction.
6359 It accepts the following values:
6365 Default value is @samp{linear}.
6370 Delay interlaced video by one field time so that the field order changes.
6372 The intended use is to fix PAL movies that have been captured with the
6373 opposite field order to the film-to-video transfer.
6375 A description of the accepted parameters follows.
6381 It accepts the following values:
6384 Capture field order top-first, transfer bottom-first.
6385 Filter will delay the bottom field.
6388 Capture field order bottom-first, transfer top-first.
6389 Filter will delay the top field.
6392 Capture and transfer with the same field order. This mode only exists
6393 for the documentation of the other options to refer to, but if you
6394 actually select it, the filter will faithfully do nothing.
6397 Capture field order determined automatically by field flags, transfer
6399 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6400 basis using field flags. If no field information is available,
6401 then this works just like @samp{u}.
6404 Capture unknown or varying, transfer opposite.
6405 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6406 analyzing the images and selecting the alternative that produces best
6407 match between the fields.
6410 Capture top-first, transfer unknown or varying.
6411 Filter selects among @samp{t} and @samp{p} using image analysis.
6414 Capture bottom-first, transfer unknown or varying.
6415 Filter selects among @samp{b} and @samp{p} using image analysis.
6418 Capture determined by field flags, transfer unknown or varying.
6419 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6420 image analysis. If no field information is available, then this works just
6421 like @samp{U}. This is the default mode.
6424 Both capture and transfer unknown or varying.
6425 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
6429 @section pixdesctest
6431 Pixel format descriptor test filter, mainly useful for internal
6432 testing. The output video should be equal to the input video.
6436 format=monow, pixdesctest
6439 can be used to test the monowhite pixel format descriptor definition.
6443 Enable the specified chain of postprocessing subfilters using libpostproc. This
6444 library should be automatically selected with a GPL build (@code{--enable-gpl}).
6445 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
6446 Each subfilter and some options have a short and a long name that can be used
6447 interchangeably, i.e. dr/dering are the same.
6449 The filters accept the following options:
6453 Set postprocessing subfilters string.
6456 All subfilters share common options to determine their scope:
6460 Honor the quality commands for this subfilter.
6463 Do chrominance filtering, too (default).
6466 Do luminance filtering only (no chrominance).
6469 Do chrominance filtering only (no luminance).
6472 These options can be appended after the subfilter name, separated by a '|'.
6474 Available subfilters are:
6477 @item hb/hdeblock[|difference[|flatness]]
6478 Horizontal deblocking filter
6481 Difference factor where higher values mean more deblocking (default: @code{32}).
6483 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6486 @item vb/vdeblock[|difference[|flatness]]
6487 Vertical deblocking filter
6490 Difference factor where higher values mean more deblocking (default: @code{32}).
6492 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6495 @item ha/hadeblock[|difference[|flatness]]
6496 Accurate horizontal deblocking filter
6499 Difference factor where higher values mean more deblocking (default: @code{32}).
6501 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6504 @item va/vadeblock[|difference[|flatness]]
6505 Accurate vertical deblocking filter
6508 Difference factor where higher values mean more deblocking (default: @code{32}).
6510 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6514 The horizontal and vertical deblocking filters share the difference and
6515 flatness values so you cannot set different horizontal and vertical
6520 Experimental horizontal deblocking filter
6523 Experimental vertical deblocking filter
6528 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
6531 larger -> stronger filtering
6533 larger -> stronger filtering
6535 larger -> stronger filtering
6538 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
6541 Stretch luminance to @code{0-255}.
6544 @item lb/linblenddeint
6545 Linear blend deinterlacing filter that deinterlaces the given block by
6546 filtering all lines with a @code{(1 2 1)} filter.
6548 @item li/linipoldeint
6549 Linear interpolating deinterlacing filter that deinterlaces the given block by
6550 linearly interpolating every second line.
6552 @item ci/cubicipoldeint
6553 Cubic interpolating deinterlacing filter deinterlaces the given block by
6554 cubically interpolating every second line.
6556 @item md/mediandeint
6557 Median deinterlacing filter that deinterlaces the given block by applying a
6558 median filter to every second line.
6560 @item fd/ffmpegdeint
6561 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
6562 second line with a @code{(-1 4 2 4 -1)} filter.
6565 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
6566 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
6568 @item fq/forceQuant[|quantizer]
6569 Overrides the quantizer table from the input with the constant quantizer you
6577 Default pp filter combination (@code{hb|a,vb|a,dr|a})
6580 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
6583 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
6586 @subsection Examples
6590 Apply horizontal and vertical deblocking, deringing and automatic
6591 brightness/contrast:
6597 Apply default filters without brightness/contrast correction:
6603 Apply default filters and temporal denoiser:
6605 pp=default/tmpnoise|1|2|3
6609 Apply deblocking on luminance only, and switch vertical deblocking on or off
6610 automatically depending on available CPU time:
6618 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
6619 Ratio) between two input videos.
6621 This filter takes in input two input videos, the first input is
6622 considered the "main" source and is passed unchanged to the
6623 output. The second input is used as a "reference" video for computing
6626 Both video inputs must have the same resolution and pixel format for
6627 this filter to work correctly. Also it assumes that both inputs
6628 have the same number of frames, which are compared one by one.
6630 The obtained average PSNR is printed through the logging system.
6632 The filter stores the accumulated MSE (mean squared error) of each
6633 frame, and at the end of the processing it is averaged across all frames
6634 equally, and the following formula is applied to obtain the PSNR:
6637 PSNR = 10*log10(MAX^2/MSE)
6640 Where MAX is the average of the maximum values of each component of the
6643 The description of the accepted parameters follows.
6647 If specified the filter will use the named file to save the PSNR of
6648 each individual frame.
6651 The file printed if @var{stats_file} is selected, contains a sequence of
6652 key/value pairs of the form @var{key}:@var{value} for each compared
6655 A description of each shown parameter follows:
6659 sequential number of the input frame, starting from 1
6662 Mean Square Error pixel-by-pixel average difference of the compared
6663 frames, averaged over all the image components.
6665 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
6666 Mean Square Error pixel-by-pixel average difference of the compared
6667 frames for the component specified by the suffix.
6669 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
6670 Peak Signal to Noise ratio of the compared frames for the component
6671 specified by the suffix.
6676 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
6677 [main][ref] psnr="stats_file=stats.log" [out]
6680 On this example the input file being processed is compared with the
6681 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
6682 is stored in @file{stats.log}.
6687 Pulldown reversal (inverse telecine) filter, capable of handling mixed
6688 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
6691 The pullup filter is designed to take advantage of future context in making
6692 its decisions. This filter is stateless in the sense that it does not lock
6693 onto a pattern to follow, but it instead looks forward to the following
6694 fields in order to identify matches and rebuild progressive frames.
6696 To produce content with an even framerate, insert the fps filter after
6697 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
6698 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
6700 The filter accepts the following options:
6707 These options set the amount of "junk" to ignore at the left, right, top, and
6708 bottom of the image, respectively. Left and right are in units of 8 pixels,
6709 while top and bottom are in units of 2 lines.
6710 The default is 8 pixels on each side.
6713 Set the strict breaks. Setting this option to 1 will reduce the chances of
6714 filter generating an occasional mismatched frame, but it may also cause an
6715 excessive number of frames to be dropped during high motion sequences.
6716 Conversely, setting it to -1 will make filter match fields more easily.
6717 This may help processing of video where there is slight blurring between
6718 the fields, but may also cause there to be interlaced frames in the output.
6719 Default value is @code{0}.
6722 Set the metric plane to use. It accepts the following values:
6728 Use chroma blue plane.
6731 Use chroma red plane.
6734 This option may be set to use chroma plane instead of the default luma plane
6735 for doing filter's computations. This may improve accuracy on very clean
6736 source material, but more likely will decrease accuracy, especially if there
6737 is chroma noise (rainbow effect) or any grayscale video.
6738 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
6739 load and make pullup usable in realtime on slow machines.
6742 For best results (without duplicated frames in the output file) it is
6743 necessary to change the output frame rate. For example, to inverse
6744 telecine NTSC input:
6746 ffmpeg -i input -vf pullup -r 24000/1001 ...
6751 Suppress a TV station logo, using an image file to determine which
6752 pixels comprise the logo. It works by filling in the pixels that
6753 comprise the logo with neighboring pixels.
6755 The filter accepts the following options:
6759 Set the filter bitmap file, which can be any image format supported by
6760 libavformat. The width and height of the image file must match those of the
6761 video stream being processed.
6764 Pixels in the provided bitmap image with a value of zero are not
6765 considered part of the logo, non-zero pixels are considered part of
6766 the logo. If you use white (255) for the logo and black (0) for the
6767 rest, you will be safe. For making the filter bitmap, it is
6768 recommended to take a screen capture of a black frame with the logo
6769 visible, and then using a threshold filter followed by the erode
6770 filter once or twice.
6772 If needed, little splotches can be fixed manually. Remember that if
6773 logo pixels are not covered, the filter quality will be much
6774 reduced. Marking too many pixels as part of the logo does not hurt as
6775 much, but it will increase the amount of blurring needed to cover over
6776 the image and will destroy more information than necessary, and extra
6777 pixels will slow things down on a large logo.
6781 Rotate video by an arbitrary angle expressed in radians.
6783 The filter accepts the following options:
6785 A description of the optional parameters follows.
6788 Set an expression for the angle by which to rotate the input video
6789 clockwise, expressed as a number of radians. A negative value will
6790 result in a counter-clockwise rotation. By default it is set to "0".
6792 This expression is evaluated for each frame.
6795 Set the output width expression, default value is "iw".
6796 This expression is evaluated just once during configuration.
6799 Set the output height expression, default value is "ih".
6800 This expression is evaluated just once during configuration.
6803 Enable bilinear interpolation if set to 1, a value of 0 disables
6804 it. Default value is 1.
6807 Set the color used to fill the output area not covered by the rotated
6808 image. For the generalsyntax of this option, check the "Color" section in the
6809 ffmpeg-utils manual. If the special value "none" is selected then no
6810 background is printed (useful for example if the background is never shown).
6812 Default value is "black".
6815 The expressions for the angle and the output size can contain the
6816 following constants and functions:
6820 sequential number of the input frame, starting from 0. It is always NAN
6821 before the first frame is filtered.
6824 time in seconds of the input frame, it is set to 0 when the filter is
6825 configured. It is always NAN before the first frame is filtered.
6829 horizontal and vertical chroma subsample values. For example for the
6830 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6834 the input video width and height
6838 the output width and height, that is the size of the padded area as
6839 specified by the @var{width} and @var{height} expressions
6843 the minimal width/height required for completely containing the input
6844 video rotated by @var{a} radians.
6846 These are only available when computing the @option{out_w} and
6847 @option{out_h} expressions.
6850 @subsection Examples
6854 Rotate the input by PI/6 radians clockwise:
6860 Rotate the input by PI/6 radians counter-clockwise:
6866 Rotate the input by 45 degrees clockwise:
6872 Apply a constant rotation with period T, starting from an angle of PI/3:
6874 rotate=PI/3+2*PI*t/T
6878 Make the input video rotation oscillating with a period of T
6879 seconds and an amplitude of A radians:
6881 rotate=A*sin(2*PI/T*t)
6885 Rotate the video, output size is chosen so that the whole rotating
6886 input video is always completely contained in the output:
6888 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
6892 Rotate the video, reduce the output size so that no background is ever
6895 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
6899 @subsection Commands
6901 The filter supports the following commands:
6905 Set the angle expression.
6906 The command accepts the same syntax of the corresponding option.
6908 If the specified expression is not valid, it is kept at its current
6914 Apply Shape Adaptive Blur.
6916 The filter accepts the following options:
6919 @item luma_radius, lr
6920 Set luma blur filter strength, must be a value in range 0.1-4.0, default
6921 value is 1.0. A greater value will result in a more blurred image, and
6922 in slower processing.
6924 @item luma_pre_filter_radius, lpfr
6925 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
6928 @item luma_strength, ls
6929 Set luma maximum difference between pixels to still be considered, must
6930 be a value in the 0.1-100.0 range, default value is 1.0.
6932 @item chroma_radius, cr
6933 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
6934 greater value will result in a more blurred image, and in slower
6937 @item chroma_pre_filter_radius, cpfr
6938 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
6940 @item chroma_strength, cs
6941 Set chroma maximum difference between pixels to still be considered,
6942 must be a value in the 0.1-100.0 range.
6945 Each chroma option value, if not explicitly specified, is set to the
6946 corresponding luma option value.
6951 Scale (resize) the input video, using the libswscale library.
6953 The scale filter forces the output display aspect ratio to be the same
6954 of the input, by changing the output sample aspect ratio.
6956 If the input image format is different from the format requested by
6957 the next filter, the scale filter will convert the input to the
6961 The filter accepts the following options, or any of the options
6962 supported by the libswscale scaler.
6964 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
6965 the complete list of scaler options.
6970 Set the output video dimension expression. Default value is the input
6973 If the value is 0, the input width is used for the output.
6975 If one of the values is -1, the scale filter will use a value that
6976 maintains the aspect ratio of the input image, calculated from the
6977 other specified dimension. If both of them are -1, the input size is
6980 If one of the values is -n with n > 1, the scale filter will also use a value
6981 that maintains the aspect ratio of the input image, calculated from the other
6982 specified dimension. After that it will, however, make sure that the calculated
6983 dimension is divisible by n and adjust the value if necessary.
6985 See below for the list of accepted constants for use in the dimension
6989 Set the interlacing mode. It accepts the following values:
6993 Force interlaced aware scaling.
6996 Do not apply interlaced scaling.
6999 Select interlaced aware scaling depending on whether the source frames
7000 are flagged as interlaced or not.
7003 Default value is @samp{0}.
7006 Set libswscale scaling flags. See
7007 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7008 complete list of values. If not explicitly specified the filter applies
7012 Set the video size. For the syntax of this option, check the "Video size"
7013 section in the ffmpeg-utils manual.
7015 @item in_color_matrix
7016 @item out_color_matrix
7017 Set in/output YCbCr color space type.
7019 This allows the autodetected value to be overridden as well as allows forcing
7020 a specific value used for the output and encoder.
7022 If not specified, the color space type depends on the pixel format.
7028 Choose automatically.
7031 Format conforming to International Telecommunication Union (ITU)
7032 Recommendation BT.709.
7035 Set color space conforming to the United States Federal Communications
7036 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7039 Set color space conforming to:
7043 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7046 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7049 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7054 Set color space conforming to SMPTE ST 240:1999.
7059 Set in/output YCbCr sample range.
7061 This allows the autodetected value to be overridden as well as allows forcing
7062 a specific value used for the output and encoder. If not specified, the
7063 range depends on the pixel format. Possible values:
7067 Choose automatically.
7070 Set full range (0-255 in case of 8-bit luma).
7073 Set "MPEG" range (16-235 in case of 8-bit luma).
7076 @item force_original_aspect_ratio
7077 Enable decreasing or increasing output video width or height if necessary to
7078 keep the original aspect ratio. Possible values:
7082 Scale the video as specified and disable this feature.
7085 The output video dimensions will automatically be decreased if needed.
7088 The output video dimensions will automatically be increased if needed.
7092 One useful instance of this option is that when you know a specific device's
7093 maximum allowed resolution, you can use this to limit the output video to
7094 that, while retaining the aspect ratio. For example, device A allows
7095 1280x720 playback, and your video is 1920x800. Using this option (set it to
7096 decrease) and specifying 1280x720 to the command line makes the output
7099 Please note that this is a different thing than specifying -1 for @option{w}
7100 or @option{h}, you still need to specify the output resolution for this option
7105 The values of the @option{w} and @option{h} options are expressions
7106 containing the following constants:
7111 the input width and height
7115 same as @var{in_w} and @var{in_h}
7119 the output (scaled) width and height
7123 same as @var{out_w} and @var{out_h}
7126 same as @var{iw} / @var{ih}
7129 input sample aspect ratio
7132 input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7136 horizontal and vertical input chroma subsample values. For example for the
7137 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7141 horizontal and vertical output chroma subsample values. For example for the
7142 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7145 @subsection Examples
7149 Scale the input video to a size of 200x100:
7154 This is equivalent to:
7165 Specify a size abbreviation for the output size:
7170 which can also be written as:
7176 Scale the input to 2x:
7182 The above is the same as:
7188 Scale the input to 2x with forced interlaced scaling:
7190 scale=2*iw:2*ih:interl=1
7194 Scale the input to half size:
7200 Increase the width, and set the height to the same size:
7206 Seek for Greek harmony:
7213 Increase the height, and set the width to 3/2 of the height:
7215 scale=w=3/2*oh:h=3/5*ih
7219 Increase the size, but make the size a multiple of the chroma
7222 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7226 Increase the width to a maximum of 500 pixels, keep the same input
7229 scale=w='min(500\, iw*3/2):h=-1'
7233 @section separatefields
7235 The @code{separatefields} takes a frame-based video input and splits
7236 each frame into its components fields, producing a new half height clip
7237 with twice the frame rate and twice the frame count.
7239 This filter use field-dominance information in frame to decide which
7240 of each pair of fields to place first in the output.
7241 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7243 @section setdar, setsar
7245 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7248 This is done by changing the specified Sample (aka Pixel) Aspect
7249 Ratio, according to the following equation:
7251 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7254 Keep in mind that the @code{setdar} filter does not modify the pixel
7255 dimensions of the video frame. Also the display aspect ratio set by
7256 this filter may be changed by later filters in the filterchain,
7257 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7260 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7261 the filter output video.
7263 Note that as a consequence of the application of this filter, the
7264 output display aspect ratio will change according to the equation
7267 Keep in mind that the sample aspect ratio set by the @code{setsar}
7268 filter may be changed by later filters in the filterchain, e.g. if
7269 another "setsar" or a "setdar" filter is applied.
7271 The filters accept the following options:
7274 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7275 Set the aspect ratio used by the filter.
7277 The parameter can be a floating point number string, an expression, or
7278 a string of the form @var{num}:@var{den}, where @var{num} and
7279 @var{den} are the numerator and denominator of the aspect ratio. If
7280 the parameter is not specified, it is assumed the value "0".
7281 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7285 Set the maximum integer value to use for expressing numerator and
7286 denominator when reducing the expressed aspect ratio to a rational.
7287 Default value is @code{100}.
7291 The parameter @var{sar} is an expression containing
7292 the following constants:
7296 the corresponding mathematical approximated values for e
7297 (euler number), pi (greek PI), phi (golden ratio)
7300 the input width and height
7303 same as @var{w} / @var{h}
7306 input sample aspect ratio
7309 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
7312 horizontal and vertical chroma subsample values. For example for the
7313 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7316 @subsection Examples
7321 To change the display aspect ratio to 16:9, specify one of the following:
7329 To change the sample aspect ratio to 10:11, specify:
7335 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7336 1000 in the aspect ratio reduction, use the command:
7338 setdar=ratio=16/9:max=1000
7346 Force field for the output video frame.
7348 The @code{setfield} filter marks the interlace type field for the
7349 output frames. It does not change the input frame, but only sets the
7350 corresponding property, which affects how the frame is treated by
7351 following filters (e.g. @code{fieldorder} or @code{yadif}).
7353 The filter accepts the following options:
7358 Available values are:
7362 Keep the same field property.
7365 Mark the frame as bottom-field-first.
7368 Mark the frame as top-field-first.
7371 Mark the frame as progressive.
7377 Show a line containing various information for each input video frame.
7378 The input video is not modified.
7380 The shown line contains a sequence of key/value pairs of the form
7381 @var{key}:@var{value}.
7383 A description of each shown parameter follows:
7387 sequential number of the input frame, starting from 0
7390 Presentation TimeStamp of the input frame, expressed as a number of
7391 time base units. The time base unit depends on the filter input pad.
7394 Presentation TimeStamp of the input frame, expressed as a number of
7398 position of the frame in the input stream, -1 if this information in
7399 unavailable and/or meaningless (for example in case of synthetic video)
7405 sample aspect ratio of the input frame, expressed in the form
7409 size of the input frame. For the syntax of this option, check the "Video size"
7410 section in the ffmpeg-utils manual.
7413 interlaced mode ("P" for "progressive", "T" for top field first, "B"
7414 for bottom field first)
7417 1 if the frame is a key frame, 0 otherwise
7420 picture type of the input frame ("I" for an I-frame, "P" for a
7421 P-frame, "B" for a B-frame, "?" for unknown type).
7422 Check also the documentation of the @code{AVPictureType} enum and of
7423 the @code{av_get_picture_type_char} function defined in
7424 @file{libavutil/avutil.h}.
7427 Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame
7429 @item plane_checksum
7430 Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
7431 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]"
7434 @section shuffleplanes
7436 Reorder and/or duplicate video planes.
7438 This filter accepts the following options:
7443 The index of the input plane to be used as the first output plane.
7446 The index of the input plane to be used as the second output plane.
7449 The index of the input plane to be used as the third output plane.
7452 The index of the input plane to be used as the fourth output plane.
7456 The first plane has the index 0. The default is to keep the input unchanged.
7460 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
7462 swaps the second and third planes of the input.
7467 Blur the input video without impacting the outlines.
7469 The filter accepts the following options:
7472 @item luma_radius, lr
7473 Set the luma radius. The option value must be a float number in
7474 the range [0.1,5.0] that specifies the variance of the gaussian filter
7475 used to blur the image (slower if larger). Default value is 1.0.
7477 @item luma_strength, ls
7478 Set the luma strength. The option value must be a float number
7479 in the range [-1.0,1.0] that configures the blurring. A value included
7480 in [0.0,1.0] will blur the image whereas a value included in
7481 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7483 @item luma_threshold, lt
7484 Set the luma threshold used as a coefficient to determine
7485 whether a pixel should be blurred or not. The option value must be an
7486 integer in the range [-30,30]. A value of 0 will filter all the image,
7487 a value included in [0,30] will filter flat areas and a value included
7488 in [-30,0] will filter edges. Default value is 0.
7490 @item chroma_radius, cr
7491 Set the chroma radius. The option value must be a float number in
7492 the range [0.1,5.0] that specifies the variance of the gaussian filter
7493 used to blur the image (slower if larger). Default value is 1.0.
7495 @item chroma_strength, cs
7496 Set the chroma strength. The option value must be a float number
7497 in the range [-1.0,1.0] that configures the blurring. A value included
7498 in [0.0,1.0] will blur the image whereas a value included in
7499 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7501 @item chroma_threshold, ct
7502 Set the chroma threshold used as a coefficient to determine
7503 whether a pixel should be blurred or not. The option value must be an
7504 integer in the range [-30,30]. A value of 0 will filter all the image,
7505 a value included in [0,30] will filter flat areas and a value included
7506 in [-30,0] will filter edges. Default value is 0.
7509 If a chroma option is not explicitly set, the corresponding luma value
7514 Convert between different stereoscopic image formats.
7516 The filters accept the following options:
7520 Set stereoscopic image format of input.
7522 Available values for input image formats are:
7525 side by side parallel (left eye left, right eye right)
7528 side by side crosseye (right eye left, left eye right)
7531 side by side parallel with half width resolution
7532 (left eye left, right eye right)
7535 side by side crosseye with half width resolution
7536 (right eye left, left eye right)
7539 above-below (left eye above, right eye below)
7542 above-below (right eye above, left eye below)
7545 above-below with half height resolution
7546 (left eye above, right eye below)
7549 above-below with half height resolution
7550 (right eye above, left eye below)
7553 alternating frames (left eye first, right eye second)
7556 alternating frames (right eye first, left eye second)
7558 Default value is @samp{sbsl}.
7562 Set stereoscopic image format of output.
7564 Available values for output image formats are all the input formats as well as:
7567 anaglyph red/blue gray
7568 (red filter on left eye, blue filter on right eye)
7571 anaglyph red/green gray
7572 (red filter on left eye, green filter on right eye)
7575 anaglyph red/cyan gray
7576 (red filter on left eye, cyan filter on right eye)
7579 anaglyph red/cyan half colored
7580 (red filter on left eye, cyan filter on right eye)
7583 anaglyph red/cyan color
7584 (red filter on left eye, cyan filter on right eye)
7587 anaglyph red/cyan color optimized with the least squares projection of dubois
7588 (red filter on left eye, cyan filter on right eye)
7591 anaglyph green/magenta gray
7592 (green filter on left eye, magenta filter on right eye)
7595 anaglyph green/magenta half colored
7596 (green filter on left eye, magenta filter on right eye)
7599 anaglyph green/magenta colored
7600 (green filter on left eye, magenta filter on right eye)
7603 anaglyph green/magenta color optimized with the least squares projection of dubois
7604 (green filter on left eye, magenta filter on right eye)
7607 anaglyph yellow/blue gray
7608 (yellow filter on left eye, blue filter on right eye)
7611 anaglyph yellow/blue half colored
7612 (yellow filter on left eye, blue filter on right eye)
7615 anaglyph yellow/blue colored
7616 (yellow filter on left eye, blue filter on right eye)
7619 anaglyph yellow/blue color optimized with the least squares projection of dubois
7620 (yellow filter on left eye, blue filter on right eye)
7623 interleaved rows (left eye has top row, right eye starts on next row)
7626 interleaved rows (right eye has top row, left eye starts on next row)
7629 mono output (left eye only)
7632 mono output (right eye only)
7635 Default value is @samp{arcd}.
7638 @subsection Examples
7642 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
7648 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
7656 Apply a simple postprocessing filter that compresses and decompresses the image
7657 at several (or - in the case of @option{quality} level @code{6} - all) shifts
7658 and average the results.
7660 The filter accepts the following options:
7664 Set quality. This option defines the number of levels for averaging. It accepts
7665 an integer in the range 0-6. If set to @code{0}, the filter will have no
7666 effect. A value of @code{6} means the higher quality. For each increment of
7667 that value the speed drops by a factor of approximately 2. Default value is
7671 Force a constant quantization parameter. If not set, the filter will use the QP
7672 from the video stream (if available).
7675 Set thresholding mode. Available modes are:
7679 Set hard thresholding (default).
7681 Set soft thresholding (better de-ringing effect, but likely blurrier).
7685 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
7686 option may cause flicker since the B-Frames have often larger QP. Default is
7687 @code{0} (not enabled).
7693 Draw subtitles on top of input video using the libass library.
7695 To enable compilation of this filter you need to configure FFmpeg with
7696 @code{--enable-libass}. This filter also requires a build with libavcodec and
7697 libavformat to convert the passed subtitles file to ASS (Advanced Substation
7698 Alpha) subtitles format.
7700 The filter accepts the following options:
7704 Set the filename of the subtitle file to read. It must be specified.
7707 Specify the size of the original video, the video for which the ASS file
7708 was composed. For the syntax of this option, check the "Video size" section in
7709 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
7710 this is necessary to correctly scale the fonts if the aspect ratio has been
7714 Set subtitles input character encoding. @code{subtitles} filter only. Only
7715 useful if not UTF-8.
7718 If the first key is not specified, it is assumed that the first value
7719 specifies the @option{filename}.
7721 For example, to render the file @file{sub.srt} on top of the input
7722 video, use the command:
7727 which is equivalent to:
7729 subtitles=filename=sub.srt
7734 Scale the input by 2x and smooth using the Super2xSaI (Scale and
7735 Interpolate) pixel art scaling algorithm.
7737 Useful for enlarging pixel art images without reducing sharpness.
7744 Apply telecine process to the video.
7746 This filter accepts the following options:
7755 The default value is @code{top}.
7759 A string of numbers representing the pulldown pattern you wish to apply.
7760 The default value is @code{23}.
7764 Some typical patterns:
7769 24p: 2332 (preferred)
7776 24p: 222222222223 ("Euro pulldown")
7782 Select the most representative frame in a given sequence of consecutive frames.
7784 The filter accepts the following options:
7788 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
7789 will pick one of them, and then handle the next batch of @var{n} frames until
7790 the end. Default is @code{100}.
7793 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
7794 value will result in a higher memory usage, so a high value is not recommended.
7796 @subsection Examples
7800 Extract one picture each 50 frames:
7806 Complete example of a thumbnail creation with @command{ffmpeg}:
7808 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
7814 Tile several successive frames together.
7816 The filter accepts the following options:
7821 Set the grid size (i.e. the number of lines and columns). For the syntax of
7822 this option, check the "Video size" section in the ffmpeg-utils manual.
7825 Set the maximum number of frames to render in the given area. It must be less
7826 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
7827 the area will be used.
7830 Set the outer border margin in pixels.
7833 Set the inner border thickness (i.e. the number of pixels between frames). For
7834 more advanced padding options (such as having different values for the edges),
7835 refer to the pad video filter.
7838 Specify the color of the unused areaFor the syntax of this option, check the
7839 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
7843 @subsection Examples
7847 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
7849 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
7851 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
7852 duplicating each output frame to accommodate the originally detected frame
7856 Display @code{5} pictures in an area of @code{3x2} frames,
7857 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
7858 mixed flat and named options:
7860 tile=3x2:nb_frames=5:padding=7:margin=2
7866 Perform various types of temporal field interlacing.
7868 Frames are counted starting from 1, so the first input frame is
7871 The filter accepts the following options:
7876 Specify the mode of the interlacing. This option can also be specified
7877 as a value alone. See below for a list of values for this option.
7879 Available values are:
7883 Move odd frames into the upper field, even into the lower field,
7884 generating a double height frame at half frame rate.
7887 Only output even frames, odd frames are dropped, generating a frame with
7888 unchanged height at half frame rate.
7891 Only output odd frames, even frames are dropped, generating a frame with
7892 unchanged height at half frame rate.
7895 Expand each frame to full height, but pad alternate lines with black,
7896 generating a frame with double height at the same input frame rate.
7898 @item interleave_top, 4
7899 Interleave the upper field from odd frames with the lower field from
7900 even frames, generating a frame with unchanged height at half frame rate.
7902 @item interleave_bottom, 5
7903 Interleave the lower field from odd frames with the upper field from
7904 even frames, generating a frame with unchanged height at half frame rate.
7906 @item interlacex2, 6
7907 Double frame rate with unchanged height. Frames are inserted each
7908 containing the second temporal field from the previous input frame and
7909 the first temporal field from the next input frame. This mode relies on
7910 the top_field_first flag. Useful for interlaced video displays with no
7911 field synchronisation.
7914 Numeric values are deprecated but are accepted for backward
7915 compatibility reasons.
7917 Default mode is @code{merge}.
7920 Specify flags influencing the filter process.
7922 Available value for @var{flags} is:
7925 @item low_pass_filter, vlfp
7926 Enable vertical low-pass filtering in the filter.
7927 Vertical low-pass filtering is required when creating an interlaced
7928 destination from a progressive source which contains high-frequency
7929 vertical detail. Filtering will reduce interlace 'twitter' and Moire
7932 Vertical low-pass filtering can only be enabled for @option{mode}
7933 @var{interleave_top} and @var{interleave_bottom}.
7940 Transpose rows with columns in the input video and optionally flip it.
7942 This filter accepts the following options:
7947 Specify the transposition direction.
7949 Can assume the following values:
7951 @item 0, 4, cclock_flip
7952 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
7960 Rotate by 90 degrees clockwise, that is:
7968 Rotate by 90 degrees counterclockwise, that is:
7975 @item 3, 7, clock_flip
7976 Rotate by 90 degrees clockwise and vertically flip, that is:
7984 For values between 4-7, the transposition is only done if the input
7985 video geometry is portrait and not landscape. These values are
7986 deprecated, the @code{passthrough} option should be used instead.
7988 Numerical values are deprecated, and should be dropped in favor of
7992 Do not apply the transposition if the input geometry matches the one
7993 specified by the specified value. It accepts the following values:
7996 Always apply transposition.
7998 Preserve portrait geometry (when @var{height} >= @var{width}).
8000 Preserve landscape geometry (when @var{width} >= @var{height}).
8003 Default value is @code{none}.
8006 For example to rotate by 90 degrees clockwise and preserve portrait
8009 transpose=dir=1:passthrough=portrait
8012 The command above can also be specified as:
8014 transpose=1:portrait
8018 Trim the input so that the output contains one continuous subpart of the input.
8020 This filter accepts the following options:
8023 Specify time of the start of the kept section, i.e. the frame with the
8024 timestamp @var{start} will be the first frame in the output.
8027 Specify time of the first frame that will be dropped, i.e. the frame
8028 immediately preceding the one with the timestamp @var{end} will be the last
8029 frame in the output.
8032 Same as @var{start}, except this option sets the start timestamp in timebase
8033 units instead of seconds.
8036 Same as @var{end}, except this option sets the end timestamp in timebase units
8040 Specify maximum duration of the output.
8043 Number of the first frame that should be passed to output.
8046 Number of the first frame that should be dropped.
8049 @option{start}, @option{end}, @option{duration} are expressed as time
8050 duration specifications, check the "Time duration" section in the
8051 ffmpeg-utils manual.
8053 Note that the first two sets of the start/end options and the @option{duration}
8054 option look at the frame timestamp, while the _frame variants simply count the
8055 frames that pass through the filter. Also note that this filter does not modify
8056 the timestamps. If you wish that the output timestamps start at zero, insert a
8057 setpts filter after the trim filter.
8059 If multiple start or end options are set, this filter tries to be greedy and
8060 keep all the frames that match at least one of the specified constraints. To keep
8061 only the part that matches all the constraints at once, chain multiple trim
8064 The defaults are such that all the input is kept. So it is possible to set e.g.
8065 just the end values to keep everything before the specified time.
8070 drop everything except the second minute of input
8072 ffmpeg -i INPUT -vf trim=60:120
8076 keep only the first second
8078 ffmpeg -i INPUT -vf trim=duration=1
8086 Sharpen or blur the input video.
8088 It accepts the following parameters:
8091 @item luma_msize_x, lx
8092 Set the luma matrix horizontal size. It must be an odd integer between
8093 3 and 63, default value is 5.
8095 @item luma_msize_y, ly
8096 Set the luma matrix vertical size. It must be an odd integer between 3
8097 and 63, default value is 5.
8099 @item luma_amount, la
8100 Set the luma effect strength. It can be a float number, reasonable
8101 values lay between -1.5 and 1.5.
8103 Negative values will blur the input video, while positive values will
8104 sharpen it, a value of zero will disable the effect.
8106 Default value is 1.0.
8108 @item chroma_msize_x, cx
8109 Set the chroma matrix horizontal size. It must be an odd integer
8110 between 3 and 63, default value is 5.
8112 @item chroma_msize_y, cy
8113 Set the chroma matrix vertical size. It must be an odd integer
8114 between 3 and 63, default value is 5.
8116 @item chroma_amount, ca
8117 Set the chroma effect strength. It can be a float number, reasonable
8118 values lay between -1.5 and 1.5.
8120 Negative values will blur the input video, while positive values will
8121 sharpen it, a value of zero will disable the effect.
8123 Default value is 0.0.
8126 If set to 1, specify using OpenCL capabilities, only available if
8127 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
8131 All parameters are optional and default to the equivalent of the
8132 string '5:5:1.0:5:5:0.0'.
8134 @subsection Examples
8138 Apply strong luma sharpen effect:
8140 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
8144 Apply strong blur of both luma and chroma parameters:
8146 unsharp=7:7:-2:7:7:-2
8150 @anchor{vidstabdetect}
8151 @section vidstabdetect
8153 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
8154 @ref{vidstabtransform} for pass 2.
8156 This filter generates a file with relative translation and rotation
8157 transform information about subsequent frames, which is then used by
8158 the @ref{vidstabtransform} filter.
8160 To enable compilation of this filter you need to configure FFmpeg with
8161 @code{--enable-libvidstab}.
8163 This filter accepts the following options:
8167 Set the path to the file used to write the transforms information.
8168 Default value is @file{transforms.trf}.
8171 Set how shaky the video is and how quick the camera is. It accepts an
8172 integer in the range 1-10, a value of 1 means little shakiness, a
8173 value of 10 means strong shakiness. Default value is 5.
8176 Set the accuracy of the detection process. It must be a value in the
8177 range 1-15. A value of 1 means low accuracy, a value of 15 means high
8178 accuracy. Default value is 15.
8181 Set stepsize of the search process. The region around minimum is
8182 scanned with 1 pixel resolution. Default value is 6.
8185 Set minimum contrast. Below this value a local measurement field is
8186 discarded. Must be a floating point value in the range 0-1. Default
8190 Set reference frame number for tripod mode.
8192 If enabled, the motion of the frames is compared to a reference frame
8193 in the filtered stream, identified by the specified number. The idea
8194 is to compensate all movements in a more-or-less static scene and keep
8195 the camera view absolutely still.
8197 If set to 0, it is disabled. The frames are counted starting from 1.
8200 Show fields and transforms in the resulting frames. It accepts an
8201 integer in the range 0-2. Default value is 0, which disables any
8205 @subsection Examples
8215 Analyze strongly shaky movie and put the results in file
8216 @file{mytransforms.trf}:
8218 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
8222 Visualize the result of internal transformations in the resulting
8225 vidstabdetect=show=1
8229 Analyze a video with medium shakiness using @command{ffmpeg}:
8231 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
8235 @anchor{vidstabtransform}
8236 @section vidstabtransform
8238 Video stabilization/deshaking: pass 2 of 2,
8239 see @ref{vidstabdetect} for pass 1.
8241 Read a file with transform information for each frame and
8242 apply/compensate them. Together with the @ref{vidstabdetect}
8243 filter this can be used to deshake videos. See also
8244 @url{http://public.hronopik.de/vid.stab}. It is important to also use
8245 the unsharp filter, see below.
8247 To enable compilation of this filter you need to configure FFmpeg with
8248 @code{--enable-libvidstab}.
8254 Set path to the file used to read the transforms. Default value is
8255 @file{transforms.trf}).
8258 Set the number of frames (value*2 + 1) used for lowpass filtering the
8259 camera movements. Default value is 10.
8261 For example a number of 10 means that 21 frames are used (10 in the
8262 past and 10 in the future) to smoothen the motion in the video. A
8263 larger values leads to a smoother video, but limits the acceleration
8264 of the camera (pan/tilt movements). 0 is a special case where a
8265 static camera is simulated.
8268 Set the camera path optimization algorithm.
8270 Accepted values are:
8273 gaussian kernel low-pass filter on camera motion (default)
8275 averaging on transformations
8279 Set maximal number of pixels to translate frames. Default value is -1,
8283 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
8284 value is -1, meaning no limit.
8287 Specify how to deal with borders that may be visible due to movement
8290 Available values are:
8293 keep image information from previous frame (default)
8295 fill the border black
8299 Invert transforms if set to 1. Default value is 0.
8302 Consider transforms as relative to previsou frame if set to 1,
8303 absolute if set to 0. Default value is 0.
8306 Set percentage to zoom. A positive value will result in a zoom-in
8307 effect, a negative value in a zoom-out effect. Default value is 0 (no
8311 Set optimal zooming to avoid borders.
8313 Accepted values are:
8318 optimal static zoom value is determined (only very strong movements
8319 will lead to visible borders) (default)
8321 optimal adaptive zoom value is determined (no borders will be
8322 visible), see @option{zoomspeed}
8325 Note that the value given at zoom is added to the one calculated here.
8328 Set percent to zoom maximally each frame (enabled when
8329 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
8333 Specify type of interpolation.
8335 Available values are:
8340 linear only horizontal
8342 linear in both directions (default)
8344 cubic in both directions (slow)
8348 Enable virtual tripod mode if set to 1, which is equivalent to
8349 @code{relative=0:smoothing=0}. Default value is 0.
8351 Use also @code{tripod} option of @ref{vidstabdetect}.
8354 Increase log verbosity if set to 1. Also the detected global motions
8355 are written to the temporary file @file{global_motions.trf}. Default
8359 @subsection Examples
8363 Use @command{ffmpeg} for a typical stabilization with default values:
8365 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
8368 Note the use of the unsharp filter which is always recommended.
8371 Zoom in a bit more and load transform data from a given file:
8373 vidstabtransform=zoom=5:input="mytransforms.trf"
8377 Smoothen the video even more:
8379 vidstabtransform=smoothing=30
8385 Flip the input video vertically.
8387 For example, to vertically flip a video with @command{ffmpeg}:
8389 ffmpeg -i in.avi -vf "vflip" out.avi
8394 Make or reverse a natural vignetting effect.
8396 The filter accepts the following options:
8400 Set lens angle expression as a number of radians.
8402 The value is clipped in the @code{[0,PI/2]} range.
8404 Default value: @code{"PI/5"}
8408 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
8412 Set forward/backward mode.
8414 Available modes are:
8417 The larger the distance from the central point, the darker the image becomes.
8420 The larger the distance from the central point, the brighter the image becomes.
8421 This can be used to reverse a vignette effect, though there is no automatic
8422 detection to extract the lens @option{angle} and other settings (yet). It can
8423 also be used to create a burning effect.
8426 Default value is @samp{forward}.
8429 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
8431 It accepts the following values:
8434 Evaluate expressions only once during the filter initialization.
8437 Evaluate expressions for each incoming frame. This is way slower than the
8438 @samp{init} mode since it requires all the scalers to be re-computed, but it
8439 allows advanced dynamic expressions.
8442 Default value is @samp{init}.
8445 Set dithering to reduce the circular banding effects. Default is @code{1}
8449 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
8450 Setting this value to the SAR of the input will make a rectangular vignetting
8451 following the dimensions of the video.
8453 Default is @code{1/1}.
8456 @subsection Expressions
8458 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
8459 following parameters.
8464 input width and height
8467 the number of input frame, starting from 0
8470 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
8471 @var{TB} units, NAN if undefined
8474 frame rate of the input video, NAN if the input frame rate is unknown
8477 the PTS (Presentation TimeStamp) of the filtered video frame,
8478 expressed in seconds, NAN if undefined
8481 time base of the input video
8485 @subsection Examples
8489 Apply simple strong vignetting effect:
8495 Make a flickering vignetting:
8497 vignette='PI/4+random(1)*PI/50':eval=frame
8504 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
8505 Deinterlacing Filter").
8507 Based on the process described by Martin Weston for BBC R&D, and
8508 implemented based on the de-interlace algorithm written by Jim
8509 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
8510 uses filter coefficients calculated by BBC R&D.
8512 There are two sets of filter coefficients, so called "simple":
8513 and "complex". Which set of filter coefficients is used can
8514 be set by passing an optional parameter:
8518 Set the interlacing filter coefficients. Accepts one of the following values:
8522 Simple filter coefficient set.
8524 More-complex filter coefficient set.
8526 Default value is @samp{complex}.
8529 Specify which frames to deinterlace. Accept one of the following values:
8533 Deinterlace all frames,
8535 Only deinterlace frames marked as interlaced.
8538 Default value is @samp{all}.
8544 Deinterlace the input video ("yadif" means "yet another deinterlacing
8547 This filter accepts the following options:
8553 The interlacing mode to adopt, accepts one of the following values:
8557 output 1 frame for each frame
8559 output 1 frame for each field
8560 @item 2, send_frame_nospatial
8561 like @code{send_frame} but skip spatial interlacing check
8562 @item 3, send_field_nospatial
8563 like @code{send_field} but skip spatial interlacing check
8566 Default value is @code{send_frame}.
8569 The picture field parity assumed for the input interlaced video, accepts one of
8570 the following values:
8574 assume top field first
8576 assume bottom field first
8578 enable automatic detection
8581 Default value is @code{auto}.
8582 If interlacing is unknown or decoder does not export this information,
8583 top field first will be assumed.
8586 Specify which frames to deinterlace. Accept one of the following
8591 deinterlace all frames
8593 only deinterlace frames marked as interlaced
8596 Default value is @code{all}.
8599 @c man end VIDEO FILTERS
8601 @chapter Video Sources
8602 @c man begin VIDEO SOURCES
8604 Below is a description of the currently available video sources.
8608 Buffer video frames, and make them available to the filter chain.
8610 This source is mainly intended for a programmatic use, in particular
8611 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
8613 This source accepts the following options:
8618 Specify the size (width and height) of the buffered video frames. For the
8619 syntax of this option, check the "Video size" section in the ffmpeg-utils
8629 A string representing the pixel format of the buffered video frames.
8630 It may be a number corresponding to a pixel format, or a pixel format
8634 Specify the timebase assumed by the timestamps of the buffered frames.
8637 Specify the frame rate expected for the video stream.
8639 @item pixel_aspect, sar
8640 Specify the sample aspect ratio assumed by the video frames.
8643 Specify the optional parameters to be used for the scale filter which
8644 is automatically inserted when an input change is detected in the
8645 input size or format.
8650 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
8653 will instruct the source to accept video frames with size 320x240 and
8654 with format "yuv410p", assuming 1/24 as the timestamps timebase and
8655 square pixels (1:1 sample aspect ratio).
8656 Since the pixel format with name "yuv410p" corresponds to the number 6
8657 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
8658 this example corresponds to:
8660 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
8663 Alternatively, the options can be specified as a flat string, but this
8664 syntax is deprecated:
8666 @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}]
8670 Create a pattern generated by an elementary cellular automaton.
8672 The initial state of the cellular automaton can be defined through the
8673 @option{filename}, and @option{pattern} options. If such options are
8674 not specified an initial state is created randomly.
8676 At each new frame a new row in the video is filled with the result of
8677 the cellular automaton next generation. The behavior when the whole
8678 frame is filled is defined by the @option{scroll} option.
8680 This source accepts the following options:
8684 Read the initial cellular automaton state, i.e. the starting row, from
8686 In the file, each non-whitespace character is considered an alive
8687 cell, a newline will terminate the row, and further characters in the
8688 file will be ignored.
8691 Read the initial cellular automaton state, i.e. the starting row, from
8692 the specified string.
8694 Each non-whitespace character in the string is considered an alive
8695 cell, a newline will terminate the row, and further characters in the
8696 string will be ignored.
8699 Set the video rate, that is the number of frames generated per second.
8702 @item random_fill_ratio, ratio
8703 Set the random fill ratio for the initial cellular automaton row. It
8704 is a floating point number value ranging from 0 to 1, defaults to
8707 This option is ignored when a file or a pattern is specified.
8709 @item random_seed, seed
8710 Set the seed for filling randomly the initial row, must be an integer
8711 included between 0 and UINT32_MAX. If not specified, or if explicitly
8712 set to -1, the filter will try to use a good random seed on a best
8716 Set the cellular automaton rule, it is a number ranging from 0 to 255.
8717 Default value is 110.
8720 Set the size of the output video. For the syntax of this option, check
8721 the "Video size" section in the ffmpeg-utils manual.
8723 If @option{filename} or @option{pattern} is specified, the size is set
8724 by default to the width of the specified initial state row, and the
8725 height is set to @var{width} * PHI.
8727 If @option{size} is set, it must contain the width of the specified
8728 pattern string, and the specified pattern will be centered in the
8731 If a filename or a pattern string is not specified, the size value
8732 defaults to "320x518" (used for a randomly generated initial state).
8735 If set to 1, scroll the output upward when all the rows in the output
8736 have been already filled. If set to 0, the new generated row will be
8737 written over the top row just after the bottom row is filled.
8740 @item start_full, full
8741 If set to 1, completely fill the output with generated rows before
8742 outputting the first frame.
8743 This is the default behavior, for disabling set the value to 0.
8746 If set to 1, stitch the left and right row edges together.
8747 This is the default behavior, for disabling set the value to 0.
8750 @subsection Examples
8754 Read the initial state from @file{pattern}, and specify an output of
8757 cellauto=f=pattern:s=200x400
8761 Generate a random initial row with a width of 200 cells, with a fill
8764 cellauto=ratio=2/3:s=200x200
8768 Create a pattern generated by rule 18 starting by a single alive cell
8769 centered on an initial row with width 100:
8771 cellauto=p=@@:s=100x400:full=0:rule=18
8775 Specify a more elaborated initial pattern:
8777 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
8784 Generate a Mandelbrot set fractal, and progressively zoom towards the
8785 point specified with @var{start_x} and @var{start_y}.
8787 This source accepts the following options:
8792 Set the terminal pts value. Default value is 400.
8795 Set the terminal scale value.
8796 Must be a floating point value. Default value is 0.3.
8799 Set the inner coloring mode, that is the algorithm used to draw the
8800 Mandelbrot fractal internal region.
8802 It shall assume one of the following values:
8807 Show time until convergence.
8809 Set color based on point closest to the origin of the iterations.
8814 Default value is @var{mincol}.
8817 Set the bailout value. Default value is 10.0.
8820 Set the maximum of iterations performed by the rendering
8821 algorithm. Default value is 7189.
8824 Set outer coloring mode.
8825 It shall assume one of following values:
8827 @item iteration_count
8828 Set iteration cound mode.
8829 @item normalized_iteration_count
8830 set normalized iteration count mode.
8832 Default value is @var{normalized_iteration_count}.
8835 Set frame rate, expressed as number of frames per second. Default
8839 Set frame size. For the syntax of this option, check the "Video
8840 size" section in the ffmpeg-utils manual. Default value is "640x480".
8843 Set the initial scale value. Default value is 3.0.
8846 Set the initial x position. Must be a floating point value between
8847 -100 and 100. Default value is -0.743643887037158704752191506114774.
8850 Set the initial y position. Must be a floating point value between
8851 -100 and 100. Default value is -0.131825904205311970493132056385139.
8856 Generate various test patterns, as generated by the MPlayer test filter.
8858 The size of the generated video is fixed, and is 256x256.
8859 This source is useful in particular for testing encoding features.
8861 This source accepts the following options:
8866 Specify the frame rate of the sourced video, as the number of frames
8867 generated per second. It has to be a string in the format
8868 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
8869 number or a valid video frame rate abbreviation. The default value is
8873 Set the video duration of the sourced video. The accepted syntax is:
8878 See also the function @code{av_parse_time()}.
8880 If not specified, or the expressed duration is negative, the video is
8881 supposed to be generated forever.
8885 Set the number or the name of the test to perform. Supported tests are:
8900 Default value is "all", which will cycle through the list of all tests.
8903 For example the following:
8908 will generate a "dc_luma" test pattern.
8912 Provide a frei0r source.
8914 To enable compilation of this filter you need to install the frei0r
8915 header and configure FFmpeg with @code{--enable-frei0r}.
8917 This source accepts the following options:
8922 The size of the video to generate. For the syntax of this option, check the
8923 "Video size" section in the ffmpeg-utils manual.
8926 Framerate of the generated video, may be a string of the form
8927 @var{num}/@var{den} or a frame rate abbreviation.
8930 The name to the frei0r source to load. For more information regarding frei0r and
8931 how to set the parameters read the section @ref{frei0r} in the description of
8935 A '|'-separated list of parameters to pass to the frei0r source.
8939 For example, to generate a frei0r partik0l source with size 200x200
8940 and frame rate 10 which is overlayed on the overlay filter main input:
8942 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
8947 Generate a life pattern.
8949 This source is based on a generalization of John Conway's life game.
8951 The sourced input represents a life grid, each pixel represents a cell
8952 which can be in one of two possible states, alive or dead. Every cell
8953 interacts with its eight neighbours, which are the cells that are
8954 horizontally, vertically, or diagonally adjacent.
8956 At each interaction the grid evolves according to the adopted rule,
8957 which specifies the number of neighbor alive cells which will make a
8958 cell stay alive or born. The @option{rule} option allows one to specify
8961 This source accepts the following options:
8965 Set the file from which to read the initial grid state. In the file,
8966 each non-whitespace character is considered an alive cell, and newline
8967 is used to delimit the end of each row.
8969 If this option is not specified, the initial grid is generated
8973 Set the video rate, that is the number of frames generated per second.
8976 @item random_fill_ratio, ratio
8977 Set the random fill ratio for the initial random grid. It is a
8978 floating point number value ranging from 0 to 1, defaults to 1/PHI.
8979 It is ignored when a file is specified.
8981 @item random_seed, seed
8982 Set the seed for filling the initial random grid, must be an integer
8983 included between 0 and UINT32_MAX. If not specified, or if explicitly
8984 set to -1, the filter will try to use a good random seed on a best
8990 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
8991 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
8992 @var{NS} specifies the number of alive neighbor cells which make a
8993 live cell stay alive, and @var{NB} the number of alive neighbor cells
8994 which make a dead cell to become alive (i.e. to "born").
8995 "s" and "b" can be used in place of "S" and "B", respectively.
8997 Alternatively a rule can be specified by an 18-bits integer. The 9
8998 high order bits are used to encode the next cell state if it is alive
8999 for each number of neighbor alive cells, the low order bits specify
9000 the rule for "borning" new cells. Higher order bits encode for an
9001 higher number of neighbor cells.
9002 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
9003 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
9005 Default value is "S23/B3", which is the original Conway's game of life
9006 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
9007 cells, and will born a new cell if there are three alive cells around
9011 Set the size of the output video. For the syntax of this option, check the
9012 "Video size" section in the ffmpeg-utils manual.
9014 If @option{filename} is specified, the size is set by default to the
9015 same size of the input file. If @option{size} is set, it must contain
9016 the size specified in the input file, and the initial grid defined in
9017 that file is centered in the larger resulting area.
9019 If a filename is not specified, the size value defaults to "320x240"
9020 (used for a randomly generated initial grid).
9023 If set to 1, stitch the left and right grid edges together, and the
9024 top and bottom edges also. Defaults to 1.
9027 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
9028 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
9029 value from 0 to 255.
9032 Set the color of living (or new born) cells.
9035 Set the color of dead cells. If @option{mold} is set, this is the first color
9036 used to represent a dead cell.
9039 Set mold color, for definitely dead and moldy cells.
9041 For the syntax of these 3 color options, check the "Color" section in the
9042 ffmpeg-utils manual.
9045 @subsection Examples
9049 Read a grid from @file{pattern}, and center it on a grid of size
9052 life=f=pattern:s=300x300
9056 Generate a random grid of size 200x200, with a fill ratio of 2/3:
9058 life=ratio=2/3:s=200x200
9062 Specify a custom rule for evolving a randomly generated grid:
9068 Full example with slow death effect (mold) using @command{ffplay}:
9070 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
9075 @anchor{haldclutsrc}
9079 @anchor{smptehdbars}
9081 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
9083 The @code{color} source provides an uniformly colored input.
9085 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
9086 @ref{haldclut} filter.
9088 The @code{nullsrc} source returns unprocessed video frames. It is
9089 mainly useful to be employed in analysis / debugging tools, or as the
9090 source for filters which ignore the input data.
9092 The @code{rgbtestsrc} source generates an RGB test pattern useful for
9093 detecting RGB vs BGR issues. You should see a red, green and blue
9094 stripe from top to bottom.
9096 The @code{smptebars} source generates a color bars pattern, based on
9097 the SMPTE Engineering Guideline EG 1-1990.
9099 The @code{smptehdbars} source generates a color bars pattern, based on
9100 the SMPTE RP 219-2002.
9102 The @code{testsrc} source generates a test video pattern, showing a
9103 color pattern, a scrolling gradient and a timestamp. This is mainly
9104 intended for testing purposes.
9106 The sources accept the following options:
9111 Specify the color of the source, only available in the @code{color}
9112 source. For the syntax of this option, check the "Color" section in the
9113 ffmpeg-utils manual.
9116 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
9117 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
9118 pixels to be used as identity matrix for 3D lookup tables. Each component is
9119 coded on a @code{1/(N*N)} scale.
9122 Specify the size of the sourced video. For the syntax of this option, check the
9123 "Video size" section in the ffmpeg-utils manual. The default value is
9126 This option is not available with the @code{haldclutsrc} filter.
9129 Specify the frame rate of the sourced video, as the number of frames
9130 generated per second. It has to be a string in the format
9131 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
9132 number or a valid video frame rate abbreviation. The default value is
9136 Set the sample aspect ratio of the sourced video.
9139 Set the video duration of the sourced video. The accepted syntax is:
9141 [-]HH[:MM[:SS[.m...]]]
9144 See also the function @code{av_parse_time()}.
9146 If not specified, or the expressed duration is negative, the video is
9147 supposed to be generated forever.
9150 Set the number of decimals to show in the timestamp, only available in the
9151 @code{testsrc} source.
9153 The displayed timestamp value will correspond to the original
9154 timestamp value multiplied by the power of 10 of the specified
9155 value. Default value is 0.
9158 For example the following:
9160 testsrc=duration=5.3:size=qcif:rate=10
9163 will generate a video with a duration of 5.3 seconds, with size
9164 176x144 and a frame rate of 10 frames per second.
9166 The following graph description will generate a red source
9167 with an opacity of 0.2, with size "qcif" and a frame rate of 10
9170 color=c=red@@0.2:s=qcif:r=10
9173 If the input content is to be ignored, @code{nullsrc} can be used. The
9174 following command generates noise in the luminance plane by employing
9175 the @code{geq} filter:
9177 nullsrc=s=256x256, geq=random(1)*255:128:128
9180 @subsection Commands
9182 The @code{color} source supports the following commands:
9186 Set the color of the created image. Accepts the same syntax of the
9187 corresponding @option{color} option.
9190 @c man end VIDEO SOURCES
9192 @chapter Video Sinks
9193 @c man begin VIDEO SINKS
9195 Below is a description of the currently available video sinks.
9199 Buffer video frames, and make them available to the end of the filter
9202 This sink is mainly intended for a programmatic use, in particular
9203 through the interface defined in @file{libavfilter/buffersink.h}
9204 or the options system.
9206 It accepts a pointer to an AVBufferSinkContext structure, which
9207 defines the incoming buffers' formats, to be passed as the opaque
9208 parameter to @code{avfilter_init_filter} for initialization.
9212 Null video sink, do absolutely nothing with the input video. It is
9213 mainly useful as a template and to be employed in analysis / debugging
9216 @c man end VIDEO SINKS
9218 @chapter Multimedia Filters
9219 @c man begin MULTIMEDIA FILTERS
9221 Below is a description of the currently available multimedia filters.
9223 @section avectorscope
9225 Convert input audio to a video output, representing the audio vector
9228 The filter is used to measure the difference between channels of stereo
9229 audio stream. A monoaural signal, consisting of identical left and right
9230 signal, results in straight vertical line. Any stereo separation is visible
9231 as a deviation from this line, creating a Lissajous figure.
9232 If the straight (or deviation from it) but horizontal line appears this
9233 indicates that the left and right channels are out of phase.
9235 The filter accepts the following options:
9239 Set the vectorscope mode.
9241 Available values are:
9244 Lissajous rotated by 45 degrees.
9247 Same as above but not rotated.
9250 Default value is @samp{lissajous}.
9253 Set the video size for the output. For the syntax of this option, check the "Video size"
9254 section in the ffmpeg-utils manual. Default value is @code{400x400}.
9257 Set the output frame rate. Default value is @code{25}.
9262 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
9263 Allowed range is @code{[0, 255]}.
9268 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
9269 Allowed range is @code{[0, 255]}.
9272 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
9275 @subsection Examples
9279 Complete example using @command{ffplay}:
9281 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9282 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
9288 Concatenate audio and video streams, joining them together one after the
9291 The filter works on segments of synchronized video and audio streams. All
9292 segments must have the same number of streams of each type, and that will
9293 also be the number of streams at output.
9295 The filter accepts the following options:
9300 Set the number of segments. Default is 2.
9303 Set the number of output video streams, that is also the number of video
9304 streams in each segment. Default is 1.
9307 Set the number of output audio streams, that is also the number of video
9308 streams in each segment. Default is 0.
9311 Activate unsafe mode: do not fail if segments have a different format.
9315 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
9316 @var{a} audio outputs.
9318 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
9319 segment, in the same order as the outputs, then the inputs for the second
9322 Related streams do not always have exactly the same duration, for various
9323 reasons including codec frame size or sloppy authoring. For that reason,
9324 related synchronized streams (e.g. a video and its audio track) should be
9325 concatenated at once. The concat filter will use the duration of the longest
9326 stream in each segment (except the last one), and if necessary pad shorter
9327 audio streams with silence.
9329 For this filter to work correctly, all segments must start at timestamp 0.
9331 All corresponding streams must have the same parameters in all segments; the
9332 filtering system will automatically select a common pixel format for video
9333 streams, and a common sample format, sample rate and channel layout for
9334 audio streams, but other settings, such as resolution, must be converted
9335 explicitly by the user.
9337 Different frame rates are acceptable but will result in variable frame rate
9338 at output; be sure to configure the output file to handle it.
9340 @subsection Examples
9344 Concatenate an opening, an episode and an ending, all in bilingual version
9345 (video in stream 0, audio in streams 1 and 2):
9347 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
9348 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
9349 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
9350 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
9354 Concatenate two parts, handling audio and video separately, using the
9355 (a)movie sources, and adjusting the resolution:
9357 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
9358 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
9359 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
9361 Note that a desync will happen at the stitch if the audio and video streams
9362 do not have exactly the same duration in the first file.
9368 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
9369 it unchanged. By default, it logs a message at a frequency of 10Hz with the
9370 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
9371 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
9373 The filter also has a video output (see the @var{video} option) with a real
9374 time graph to observe the loudness evolution. The graphic contains the logged
9375 message mentioned above, so it is not printed anymore when this option is set,
9376 unless the verbose logging is set. The main graphing area contains the
9377 short-term loudness (3 seconds of analysis), and the gauge on the right is for
9378 the momentary loudness (400 milliseconds).
9380 More information about the Loudness Recommendation EBU R128 on
9381 @url{http://tech.ebu.ch/loudness}.
9383 The filter accepts the following options:
9388 Activate the video output. The audio stream is passed unchanged whether this
9389 option is set or no. The video stream will be the first output stream if
9390 activated. Default is @code{0}.
9393 Set the video size. This option is for video only. For the syntax of this
9394 option, check the "Video size" section in the ffmpeg-utils manual. Default
9395 and minimum resolution is @code{640x480}.
9398 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
9399 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
9400 other integer value between this range is allowed.
9403 Set metadata injection. If set to @code{1}, the audio input will be segmented
9404 into 100ms output frames, each of them containing various loudness information
9405 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
9407 Default is @code{0}.
9410 Force the frame logging level.
9412 Available values are:
9415 information logging level
9417 verbose logging level
9420 By default, the logging level is set to @var{info}. If the @option{video} or
9421 the @option{metadata} options are set, it switches to @var{verbose}.
9426 Available modes can be cumulated (the option is a @code{flag} type). Possible
9430 Disable any peak mode (default).
9432 Enable sample-peak mode.
9434 Simple peak mode looking for the higher sample value. It logs a message
9435 for sample-peak (identified by @code{SPK}).
9437 Enable true-peak mode.
9439 If enabled, the peak lookup is done on an over-sampled version of the input
9440 stream for better peak accuracy. It logs a message for true-peak.
9441 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
9442 This mode requires a build with @code{libswresample}.
9447 @subsection Examples
9451 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
9453 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
9457 Run an analysis with @command{ffmpeg}:
9459 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
9463 @section interleave, ainterleave
9465 Temporally interleave frames from several inputs.
9467 @code{interleave} works with video inputs, @code{ainterleave} with audio.
9469 These filters read frames from several inputs and send the oldest
9470 queued frame to the output.
9472 Input streams must have a well defined, monotonically increasing frame
9475 In order to submit one frame to output, these filters need to enqueue
9476 at least one frame for each input, so they cannot work in case one
9477 input is not yet terminated and will not receive incoming frames.
9479 For example consider the case when one input is a @code{select} filter
9480 which always drop input frames. The @code{interleave} filter will keep
9481 reading from that input, but it will never be able to send new frames
9482 to output until the input will send an end-of-stream signal.
9484 Also, depending on inputs synchronization, the filters will drop
9485 frames in case one input receives more frames than the other ones, and
9486 the queue is already filled.
9488 These filters accept the following options:
9492 Set the number of different inputs, it is 2 by default.
9495 @subsection Examples
9499 Interleave frames belonging to different streams using @command{ffmpeg}:
9501 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
9505 Add flickering blur effect:
9507 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
9511 @section perms, aperms
9513 Set read/write permissions for the output frames.
9515 These filters are mainly aimed at developers to test direct path in the
9516 following filter in the filtergraph.
9518 The filters accept the following options:
9522 Select the permissions mode.
9524 It accepts the following values:
9527 Do nothing. This is the default.
9529 Set all the output frames read-only.
9531 Set all the output frames directly writable.
9533 Make the frame read-only if writable, and writable if read-only.
9535 Set each output frame read-only or writable randomly.
9539 Set the seed for the @var{random} mode, must be an integer included between
9540 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
9541 @code{-1}, the filter will try to use a good random seed on a best effort
9545 Note: in case of auto-inserted filter between the permission filter and the
9546 following one, the permission might not be received as expected in that
9547 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
9548 perms/aperms filter can avoid this problem.
9550 @section select, aselect
9552 Select frames to pass in output.
9554 This filter accepts the following options:
9559 Set expression, which is evaluated for each input frame.
9561 If the expression is evaluated to zero, the frame is discarded.
9563 If the evaluation result is negative or NaN, the frame is sent to the
9564 first output; otherwise it is sent to the output with index
9565 @code{ceil(val)-1}, assuming that the input index starts from 0.
9567 For example a value of @code{1.2} corresponds to the output with index
9568 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
9571 Set the number of outputs. The output to which to send the selected
9572 frame is based on the result of the evaluation. Default value is 1.
9575 The expression can contain the following constants:
9579 the sequential number of the filtered frame, starting from 0
9582 the sequential number of the selected frame, starting from 0
9584 @item prev_selected_n
9585 the sequential number of the last selected frame, NAN if undefined
9588 timebase of the input timestamps
9591 the PTS (Presentation TimeStamp) of the filtered video frame,
9592 expressed in @var{TB} units, NAN if undefined
9595 the PTS (Presentation TimeStamp) of the filtered video frame,
9596 expressed in seconds, NAN if undefined
9599 the PTS of the previously filtered video frame, NAN if undefined
9601 @item prev_selected_pts
9602 the PTS of the last previously filtered video frame, NAN if undefined
9604 @item prev_selected_t
9605 the PTS of the last previously selected video frame, NAN if undefined
9608 the PTS of the first video frame in the video, NAN if undefined
9611 the time of the first video frame in the video, NAN if undefined
9613 @item pict_type @emph{(video only)}
9614 the type of the filtered frame, can assume one of the following
9626 @item interlace_type @emph{(video only)}
9627 the frame interlace type, can assume one of the following values:
9630 the frame is progressive (not interlaced)
9632 the frame is top-field-first
9634 the frame is bottom-field-first
9637 @item consumed_sample_n @emph{(audio only)}
9638 the number of selected samples before the current frame
9640 @item samples_n @emph{(audio only)}
9641 the number of samples in the current frame
9643 @item sample_rate @emph{(audio only)}
9644 the input sample rate
9647 1 if the filtered frame is a key-frame, 0 otherwise
9650 the position in the file of the filtered frame, -1 if the information
9651 is not available (e.g. for synthetic video)
9653 @item scene @emph{(video only)}
9654 value between 0 and 1 to indicate a new scene; a low value reflects a low
9655 probability for the current frame to introduce a new scene, while a higher
9656 value means the current frame is more likely to be one (see the example below)
9660 The default value of the select expression is "1".
9662 @subsection Examples
9666 Select all frames in input:
9671 The example above is the same as:
9683 Select only I-frames:
9685 select='eq(pict_type\,I)'
9689 Select one frame every 100:
9691 select='not(mod(n\,100))'
9695 Select only frames contained in the 10-20 time interval:
9697 select=between(t\,10\,20)
9701 Select only I frames contained in the 10-20 time interval:
9703 select=between(t\,10\,20)*eq(pict_type\,I)
9707 Select frames with a minimum distance of 10 seconds:
9709 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
9713 Use aselect to select only audio frames with samples number > 100:
9715 aselect='gt(samples_n\,100)'
9719 Create a mosaic of the first scenes:
9721 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
9724 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
9728 Send even and odd frames to separate outputs, and compose them:
9730 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
9734 @section sendcmd, asendcmd
9736 Send commands to filters in the filtergraph.
9738 These filters read commands to be sent to other filters in the
9741 @code{sendcmd} must be inserted between two video filters,
9742 @code{asendcmd} must be inserted between two audio filters, but apart
9743 from that they act the same way.
9745 The specification of commands can be provided in the filter arguments
9746 with the @var{commands} option, or in a file specified by the
9747 @var{filename} option.
9749 These filters accept the following options:
9752 Set the commands to be read and sent to the other filters.
9754 Set the filename of the commands to be read and sent to the other
9758 @subsection Commands syntax
9760 A commands description consists of a sequence of interval
9761 specifications, comprising a list of commands to be executed when a
9762 particular event related to that interval occurs. The occurring event
9763 is typically the current frame time entering or leaving a given time
9766 An interval is specified by the following syntax:
9768 @var{START}[-@var{END}] @var{COMMANDS};
9771 The time interval is specified by the @var{START} and @var{END} times.
9772 @var{END} is optional and defaults to the maximum time.
9774 The current frame time is considered within the specified interval if
9775 it is included in the interval [@var{START}, @var{END}), that is when
9776 the time is greater or equal to @var{START} and is lesser than
9779 @var{COMMANDS} consists of a sequence of one or more command
9780 specifications, separated by ",", relating to that interval. The
9781 syntax of a command specification is given by:
9783 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
9786 @var{FLAGS} is optional and specifies the type of events relating to
9787 the time interval which enable sending the specified command, and must
9788 be a non-null sequence of identifier flags separated by "+" or "|" and
9789 enclosed between "[" and "]".
9791 The following flags are recognized:
9794 The command is sent when the current frame timestamp enters the
9795 specified interval. In other words, the command is sent when the
9796 previous frame timestamp was not in the given interval, and the
9800 The command is sent when the current frame timestamp leaves the
9801 specified interval. In other words, the command is sent when the
9802 previous frame timestamp was in the given interval, and the
9806 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
9809 @var{TARGET} specifies the target of the command, usually the name of
9810 the filter class or a specific filter instance name.
9812 @var{COMMAND} specifies the name of the command for the target filter.
9814 @var{ARG} is optional and specifies the optional list of argument for
9815 the given @var{COMMAND}.
9817 Between one interval specification and another, whitespaces, or
9818 sequences of characters starting with @code{#} until the end of line,
9819 are ignored and can be used to annotate comments.
9821 A simplified BNF description of the commands specification syntax
9824 @var{COMMAND_FLAG} ::= "enter" | "leave"
9825 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
9826 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
9827 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
9828 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
9829 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
9832 @subsection Examples
9836 Specify audio tempo change at second 4:
9838 asendcmd=c='4.0 atempo tempo 1.5',atempo
9842 Specify a list of drawtext and hue commands in a file.
9844 # show text in the interval 5-10
9845 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
9846 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
9848 # desaturate the image in the interval 15-20
9849 15.0-20.0 [enter] hue s 0,
9850 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
9852 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
9854 # apply an exponential saturation fade-out effect, starting from time 25
9855 25 [enter] hue s exp(25-t)
9858 A filtergraph allowing to read and process the above command list
9859 stored in a file @file{test.cmd}, can be specified with:
9861 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
9866 @section setpts, asetpts
9868 Change the PTS (presentation timestamp) of the input frames.
9870 @code{setpts} works on video frames, @code{asetpts} on audio frames.
9872 This filter accepts the following options:
9877 The expression which is evaluated for each frame to construct its timestamp.
9881 The expression is evaluated through the eval API and can contain the following
9886 frame rate, only defined for constant frame-rate video
9889 the presentation timestamp in input
9892 the count of the input frame for video or the number of consumed samples,
9893 not including the current frame for audio, starting from 0.
9895 @item NB_CONSUMED_SAMPLES
9896 the number of consumed samples, not including the current frame (only
9900 the number of samples in the current frame (only audio)
9902 @item SAMPLE_RATE, SR
9906 the PTS of the first frame
9909 the time in seconds of the first frame
9912 tell if the current frame is interlaced
9915 the time in seconds of the current frame
9918 original position in the file of the frame, or undefined if undefined
9919 for the current frame
9925 previous input time in seconds
9931 previous output time in seconds
9934 wallclock (RTC) time in microseconds. This is deprecated, use time(0)
9938 wallclock (RTC) time at the start of the movie in microseconds
9941 timebase of the input timestamps
9945 @subsection Examples
9949 Start counting PTS from zero
9955 Apply fast motion effect:
9961 Apply slow motion effect:
9967 Set fixed rate of 25 frames per second:
9973 Set fixed rate 25 fps with some jitter:
9975 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
9979 Apply an offset of 10 seconds to the input PTS:
9985 Generate timestamps from a "live source" and rebase onto the current timebase:
9987 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
9991 Generate timestamps by counting samples:
9998 @section settb, asettb
10000 Set the timebase to use for the output frames timestamps.
10001 It is mainly useful for testing timebase configuration.
10003 This filter accepts the following options:
10008 The expression which is evaluated into the output timebase.
10012 The value for @option{tb} is an arithmetic expression representing a
10013 rational. The expression can contain the constants "AVTB" (the default
10014 timebase), "intb" (the input timebase) and "sr" (the sample rate,
10015 audio only). Default value is "intb".
10017 @subsection Examples
10021 Set the timebase to 1/25:
10027 Set the timebase to 1/10:
10033 Set the timebase to 1001/1000:
10039 Set the timebase to 2*intb:
10045 Set the default timebase value:
10051 @section showspectrum
10053 Convert input audio to a video output, representing the audio frequency
10056 The filter accepts the following options:
10060 Specify the video size for the output. For the syntax of this option, check
10061 the "Video size" section in the ffmpeg-utils manual. Default value is
10065 Specify if the spectrum should slide along the window. Default value is
10069 Specify display mode.
10071 It accepts the following values:
10074 all channels are displayed in the same row
10076 all channels are displayed in separate rows
10079 Default value is @samp{combined}.
10082 Specify display color mode.
10084 It accepts the following values:
10087 each channel is displayed in a separate color
10089 each channel is is displayed using the same color scheme
10092 Default value is @samp{channel}.
10095 Specify scale used for calculating intensity color values.
10097 It accepts the following values:
10102 square root, default
10109 Default value is @samp{sqrt}.
10112 Set saturation modifier for displayed colors. Negative values provide
10113 alternative color scheme. @code{0} is no saturation at all.
10114 Saturation must be in [-10.0, 10.0] range.
10115 Default value is @code{1}.
10118 Set window function.
10120 It accepts the following values:
10123 No samples pre-processing (do not expect this to be faster)
10132 Default value is @code{hann}.
10135 The usage is very similar to the showwaves filter; see the examples in that
10138 @subsection Examples
10142 Large window with logarithmic color scaling:
10144 showspectrum=s=1280x480:scale=log
10148 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
10150 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10151 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
10157 Convert input audio to a video output, representing the samples waves.
10159 The filter accepts the following options:
10163 Specify the video size for the output. For the syntax of this option, check
10164 the "Video size" section in the ffmpeg-utils manual. Default value
10170 Available values are:
10173 Draw a point for each sample.
10176 Draw a vertical line for each sample.
10179 Default value is @code{point}.
10182 Set the number of samples which are printed on the same column. A
10183 larger value will decrease the frame rate. Must be a positive
10184 integer. This option can be set only if the value for @var{rate}
10185 is not explicitly specified.
10188 Set the (approximate) output frame rate. This is done by setting the
10189 option @var{n}. Default value is "25".
10193 @subsection Examples
10197 Output the input file audio and the corresponding video representation
10200 amovie=a.mp3,asplit[out0],showwaves[out1]
10204 Create a synthetic signal and show it with showwaves, forcing a
10205 frame rate of 30 frames per second:
10207 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
10211 @section split, asplit
10213 Split input into several identical outputs.
10215 @code{asplit} works with audio input, @code{split} with video.
10217 The filter accepts a single parameter which specifies the number of outputs. If
10218 unspecified, it defaults to 2.
10220 @subsection Examples
10224 Create two separate outputs from the same input:
10226 [in] split [out0][out1]
10230 To create 3 or more outputs, you need to specify the number of
10233 [in] asplit=3 [out0][out1][out2]
10237 Create two separate outputs from the same input, one cropped and
10240 [in] split [splitout1][splitout2];
10241 [splitout1] crop=100:100:0:0 [cropout];
10242 [splitout2] pad=200:200:100:100 [padout];
10246 Create 5 copies of the input audio with @command{ffmpeg}:
10248 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
10254 Receive commands sent through a libzmq client, and forward them to
10255 filters in the filtergraph.
10257 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
10258 must be inserted between two video filters, @code{azmq} between two
10261 To enable these filters you need to install the libzmq library and
10262 headers and configure FFmpeg with @code{--enable-libzmq}.
10264 For more information about libzmq see:
10265 @url{http://www.zeromq.org/}
10267 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
10268 receives messages sent through a network interface defined by the
10269 @option{bind_address} option.
10271 The received message must be in the form:
10273 @var{TARGET} @var{COMMAND} [@var{ARG}]
10276 @var{TARGET} specifies the target of the command, usually the name of
10277 the filter class or a specific filter instance name.
10279 @var{COMMAND} specifies the name of the command for the target filter.
10281 @var{ARG} is optional and specifies the optional argument list for the
10282 given @var{COMMAND}.
10284 Upon reception, the message is processed and the corresponding command
10285 is injected into the filtergraph. Depending on the result, the filter
10286 will send a reply to the client, adopting the format:
10288 @var{ERROR_CODE} @var{ERROR_REASON}
10292 @var{MESSAGE} is optional.
10294 @subsection Examples
10296 Look at @file{tools/zmqsend} for an example of a zmq client which can
10297 be used to send commands processed by these filters.
10299 Consider the following filtergraph generated by @command{ffplay}
10301 ffplay -dumpgraph 1 -f lavfi "
10302 color=s=100x100:c=red [l];
10303 color=s=100x100:c=blue [r];
10304 nullsrc=s=200x100, zmq [bg];
10305 [bg][l] overlay [bg+l];
10306 [bg+l][r] overlay=x=100 "
10309 To change the color of the left side of the video, the following
10310 command can be used:
10312 echo Parsed_color_0 c yellow | tools/zmqsend
10315 To change the right side:
10317 echo Parsed_color_1 c pink | tools/zmqsend
10320 @c man end MULTIMEDIA FILTERS
10322 @chapter Multimedia Sources
10323 @c man begin MULTIMEDIA SOURCES
10325 Below is a description of the currently available multimedia sources.
10329 This is the same as @ref{movie} source, except it selects an audio
10335 Read audio and/or video stream(s) from a movie container.
10337 This filter accepts the following options:
10341 The name of the resource to read (not necessarily a file but also a device or a
10342 stream accessed through some protocol).
10344 @item format_name, f
10345 Specifies the format assumed for the movie to read, and can be either
10346 the name of a container or an input device. If not specified the
10347 format is guessed from @var{movie_name} or by probing.
10349 @item seek_point, sp
10350 Specifies the seek point in seconds, the frames will be output
10351 starting from this seek point, the parameter is evaluated with
10352 @code{av_strtod} so the numerical value may be suffixed by an IS
10353 postfix. Default value is "0".
10356 Specifies the streams to read. Several streams can be specified,
10357 separated by "+". The source will then have as many outputs, in the
10358 same order. The syntax is explained in the ``Stream specifiers''
10359 section in the ffmpeg manual. Two special names, "dv" and "da" specify
10360 respectively the default (best suited) video and audio stream. Default
10361 is "dv", or "da" if the filter is called as "amovie".
10363 @item stream_index, si
10364 Specifies the index of the video stream to read. If the value is -1,
10365 the best suited video stream will be automatically selected. Default
10366 value is "-1". Deprecated. If the filter is called "amovie", it will select
10367 audio instead of video.
10370 Specifies how many times to read the stream in sequence.
10371 If the value is less than 1, the stream will be read again and again.
10372 Default value is "1".
10374 Note that when the movie is looped the source timestamps are not
10375 changed, so it will generate non monotonically increasing timestamps.
10378 This filter allows one to overlay a second video on top of main input of
10379 a filtergraph as shown in this graph:
10381 input -----------> deltapts0 --> overlay --> output
10384 movie --> scale--> deltapts1 -------+
10387 @subsection Examples
10391 Skip 3.2 seconds from the start of the avi file in.avi, and overlay it
10392 on top of the input labelled as "in":
10394 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
10395 [in] setpts=PTS-STARTPTS [main];
10396 [main][over] overlay=16:16 [out]
10400 Read from a video4linux2 device, and overlay it on top of the input
10403 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
10404 [in] setpts=PTS-STARTPTS [main];
10405 [main][over] overlay=16:16 [out]
10409 Read the first video stream and the audio stream with id 0x81 from
10410 dvd.vob; the video is connected to the pad named "video" and the audio is
10411 connected to the pad named "audio":
10413 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
10417 @c man end MULTIMEDIA SOURCES