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 Set when the volume expression is evaluated.
1836 It accepts the following values:
1839 only evaluate expression once during the filter initialization, or
1840 when the @samp{volume} command is sent
1843 evaluate expression for each incoming frame
1846 Default value is @samp{once}.
1849 The volume expression can contain the following parameters.
1853 frame number (starting at zero)
1856 @item nb_consumed_samples
1857 number of samples consumed by the filter
1859 number of samples in the current frame
1861 original frame position in the file
1867 PTS at start of stream
1869 time at start of stream
1875 last set volume value
1878 Note that when @option{eval} is set to @samp{once} only the
1879 @var{sample_rate} and @var{tb} variables are available, all other
1880 variables will evaluate to NAN.
1882 @subsection Commands
1884 This filter supports the following commands:
1887 Modify the volume expression.
1888 The command accepts the same syntax of the corresponding option.
1890 If the specified expression is not valid, it is kept at its current
1894 @subsection Examples
1898 Halve the input audio volume:
1902 volume=volume=-6.0206dB
1905 In all the above example the named key for @option{volume} can be
1906 omitted, for example like in:
1912 Increase input audio power by 6 decibels using fixed-point precision:
1914 volume=volume=6dB:precision=fixed
1918 Fade volume after time 10 with an annihilation period of 5 seconds:
1920 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
1924 @section volumedetect
1926 Detect the volume of the input video.
1928 The filter has no parameters. The input is not modified. Statistics about
1929 the volume will be printed in the log when the input stream end is reached.
1931 In particular it will show the mean volume (root mean square), maximum
1932 volume (on a per-sample basis), and the beginning of a histogram of the
1933 registered volume values (from the maximum value to a cumulated 1/1000 of
1936 All volumes are in decibels relative to the maximum PCM value.
1938 @subsection Examples
1940 Here is an excerpt of the output:
1942 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
1943 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
1944 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
1945 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
1946 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
1947 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
1948 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
1949 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
1950 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
1956 The mean square energy is approximately -27 dB, or 10^-2.7.
1958 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
1960 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
1963 In other words, raising the volume by +4 dB does not cause any clipping,
1964 raising it by +5 dB causes clipping for 6 samples, etc.
1966 @c man end AUDIO FILTERS
1968 @chapter Audio Sources
1969 @c man begin AUDIO SOURCES
1971 Below is a description of the currently available audio sources.
1975 Buffer audio frames, and make them available to the filter chain.
1977 This source is mainly intended for a programmatic use, in particular
1978 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
1980 It accepts the following named parameters:
1985 Timebase which will be used for timestamps of submitted frames. It must be
1986 either a floating-point number or in @var{numerator}/@var{denominator} form.
1989 The sample rate of the incoming audio buffers.
1992 The sample format of the incoming audio buffers.
1993 Either a sample format name or its corresponging integer representation from
1994 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
1996 @item channel_layout
1997 The channel layout of the incoming audio buffers.
1998 Either a channel layout name from channel_layout_map in
1999 @file{libavutil/channel_layout.c} or its corresponding integer representation
2000 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2003 The number of channels of the incoming audio buffers.
2004 If both @var{channels} and @var{channel_layout} are specified, then they
2009 @subsection Examples
2012 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2015 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2016 Since the sample format with name "s16p" corresponds to the number
2017 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2020 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2025 Generate an audio signal specified by an expression.
2027 This source accepts in input one or more expressions (one for each
2028 channel), which are evaluated and used to generate a corresponding
2031 This source accepts the following options:
2035 Set the '|'-separated expressions list for each separate channel. In case the
2036 @option{channel_layout} option is not specified, the selected channel layout
2037 depends on the number of provided expressions. Otherwise the last
2038 specified expression is applied to the remaining output channels.
2040 @item channel_layout, c
2041 Set the channel layout. The number of channels in the specified layout
2042 must be equal to the number of specified expressions.
2045 Set the minimum duration of the sourced audio. See the function
2046 @code{av_parse_time()} for the accepted format.
2047 Note that the resulting duration may be greater than the specified
2048 duration, as the generated audio is always cut at the end of a
2051 If not specified, or the expressed duration is negative, the audio is
2052 supposed to be generated forever.
2055 Set the number of samples per channel per each output frame,
2058 @item sample_rate, s
2059 Specify the sample rate, default to 44100.
2062 Each expression in @var{exprs} can contain the following constants:
2066 number of the evaluated sample, starting from 0
2069 time of the evaluated sample expressed in seconds, starting from 0
2076 @subsection Examples
2086 Generate a sin signal with frequency of 440 Hz, set sample rate to
2089 aevalsrc="sin(440*2*PI*t):s=8000"
2093 Generate a two channels signal, specify the channel layout (Front
2094 Center + Back Center) explicitly:
2096 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2100 Generate white noise:
2102 aevalsrc="-2+random(0)"
2106 Generate an amplitude modulated signal:
2108 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2112 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2114 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2121 Null audio source, return unprocessed audio frames. It is mainly useful
2122 as a template and to be employed in analysis / debugging tools, or as
2123 the source for filters which ignore the input data (for example the sox
2126 This source accepts the following options:
2130 @item channel_layout, cl
2132 Specify the channel layout, and can be either an integer or a string
2133 representing a channel layout. The default value of @var{channel_layout}
2136 Check the channel_layout_map definition in
2137 @file{libavutil/channel_layout.c} for the mapping between strings and
2138 channel layout values.
2140 @item sample_rate, r
2141 Specify the sample rate, and defaults to 44100.
2144 Set the number of samples per requested frames.
2148 @subsection Examples
2152 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2154 anullsrc=r=48000:cl=4
2158 Do the same operation with a more obvious syntax:
2160 anullsrc=r=48000:cl=mono
2164 All the parameters need to be explicitly defined.
2168 Synthesize a voice utterance using the libflite library.
2170 To enable compilation of this filter you need to configure FFmpeg with
2171 @code{--enable-libflite}.
2173 Note that the flite library is not thread-safe.
2175 The filter accepts the following options:
2180 If set to 1, list the names of the available voices and exit
2181 immediately. Default value is 0.
2184 Set the maximum number of samples per frame. Default value is 512.
2187 Set the filename containing the text to speak.
2190 Set the text to speak.
2193 Set the voice to use for the speech synthesis. Default value is
2194 @code{kal}. See also the @var{list_voices} option.
2197 @subsection Examples
2201 Read from file @file{speech.txt}, and synthetize the text using the
2202 standard flite voice:
2204 flite=textfile=speech.txt
2208 Read the specified text selecting the @code{slt} voice:
2210 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2214 Input text to ffmpeg:
2216 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2220 Make @file{ffplay} speak the specified text, using @code{flite} and
2221 the @code{lavfi} device:
2223 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2227 For more information about libflite, check:
2228 @url{http://www.speech.cs.cmu.edu/flite/}
2232 Generate an audio signal made of a sine wave with amplitude 1/8.
2234 The audio signal is bit-exact.
2236 The filter accepts the following options:
2241 Set the carrier frequency. Default is 440 Hz.
2243 @item beep_factor, b
2244 Enable a periodic beep every second with frequency @var{beep_factor} times
2245 the carrier frequency. Default is 0, meaning the beep is disabled.
2247 @item sample_rate, r
2248 Specify the sample rate, default is 44100.
2251 Specify the duration of the generated audio stream.
2253 @item samples_per_frame
2254 Set the number of samples per output frame, default is 1024.
2257 @subsection Examples
2262 Generate a simple 440 Hz sine wave:
2268 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2272 sine=frequency=220:beep_factor=4:duration=5
2277 @c man end AUDIO SOURCES
2279 @chapter Audio Sinks
2280 @c man begin AUDIO SINKS
2282 Below is a description of the currently available audio sinks.
2284 @section abuffersink
2286 Buffer audio frames, and make them available to the end of filter chain.
2288 This sink is mainly intended for programmatic use, in particular
2289 through the interface defined in @file{libavfilter/buffersink.h}
2290 or the options system.
2292 It accepts a pointer to an AVABufferSinkContext structure, which
2293 defines the incoming buffers' formats, to be passed as the opaque
2294 parameter to @code{avfilter_init_filter} for initialization.
2298 Null audio sink, do absolutely nothing with the input audio. It is
2299 mainly useful as a template and to be employed in analysis / debugging
2302 @c man end AUDIO SINKS
2304 @chapter Video Filters
2305 @c man begin VIDEO FILTERS
2307 When you configure your FFmpeg build, you can disable any of the
2308 existing filters using @code{--disable-filters}.
2309 The configure output will show the video filters included in your
2312 Below is a description of the currently available video filters.
2314 @section alphaextract
2316 Extract the alpha component from the input as a grayscale video. This
2317 is especially useful with the @var{alphamerge} filter.
2321 Add or replace the alpha component of the primary input with the
2322 grayscale value of a second input. This is intended for use with
2323 @var{alphaextract} to allow the transmission or storage of frame
2324 sequences that have alpha in a format that doesn't support an alpha
2327 For example, to reconstruct full frames from a normal YUV-encoded video
2328 and a separate video created with @var{alphaextract}, you might use:
2330 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2333 Since this filter is designed for reconstruction, it operates on frame
2334 sequences without considering timestamps, and terminates when either
2335 input reaches end of stream. This will cause problems if your encoding
2336 pipeline drops frames. If you're trying to apply an image as an
2337 overlay to a video stream, consider the @var{overlay} filter instead.
2341 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2342 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2343 Substation Alpha) subtitles files.
2347 Compute the bounding box for the non-black pixels in the input frame
2350 This filter computes the bounding box containing all the pixels with a
2351 luminance value greater than the minimum allowed value.
2352 The parameters describing the bounding box are printed on the filter
2355 The filter accepts the following option:
2359 Set the minimal luminance value. Default is @code{16}.
2362 @section blackdetect
2364 Detect video intervals that are (almost) completely black. Can be
2365 useful to detect chapter transitions, commercials, or invalid
2366 recordings. Output lines contains the time for the start, end and
2367 duration of the detected black interval expressed in seconds.
2369 In order to display the output lines, you need to set the loglevel at
2370 least to the AV_LOG_INFO value.
2372 The filter accepts the following options:
2375 @item black_min_duration, d
2376 Set the minimum detected black duration expressed in seconds. It must
2377 be a non-negative floating point number.
2379 Default value is 2.0.
2381 @item picture_black_ratio_th, pic_th
2382 Set the threshold for considering a picture "black".
2383 Express the minimum value for the ratio:
2385 @var{nb_black_pixels} / @var{nb_pixels}
2388 for which a picture is considered black.
2389 Default value is 0.98.
2391 @item pixel_black_th, pix_th
2392 Set the threshold for considering a pixel "black".
2394 The threshold expresses the maximum pixel luminance value for which a
2395 pixel is considered "black". The provided value is scaled according to
2396 the following equation:
2398 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2401 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2402 the input video format, the range is [0-255] for YUV full-range
2403 formats and [16-235] for YUV non full-range formats.
2405 Default value is 0.10.
2408 The following example sets the maximum pixel threshold to the minimum
2409 value, and detects only black intervals of 2 or more seconds:
2411 blackdetect=d=2:pix_th=0.00
2416 Detect frames that are (almost) completely black. Can be useful to
2417 detect chapter transitions or commercials. Output lines consist of
2418 the frame number of the detected frame, the percentage of blackness,
2419 the position in the file if known or -1 and the timestamp in seconds.
2421 In order to display the output lines, you need to set the loglevel at
2422 least to the AV_LOG_INFO value.
2424 The filter accepts the following options:
2429 Set the percentage of the pixels that have to be below the threshold, defaults
2432 @item threshold, thresh
2433 Set the threshold below which a pixel value is considered black, defaults to
2440 Blend two video frames into each other.
2442 It takes two input streams and outputs one stream, the first input is the
2443 "top" layer and second input is "bottom" layer.
2444 Output terminates when shortest input terminates.
2446 A description of the accepted options follows.
2454 Set blend mode for specific pixel component or all pixel components in case
2455 of @var{all_mode}. Default value is @code{normal}.
2457 Available values for component modes are:
2490 Set blend opacity for specific pixel component or all pixel components in case
2491 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2498 Set blend expression for specific pixel component or all pixel components in case
2499 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2501 The expressions can use the following variables:
2505 The sequential number of the filtered frame, starting from @code{0}.
2509 the coordinates of the current sample
2513 the width and height of currently filtered plane
2517 Width and height scale depending on the currently filtered plane. It is the
2518 ratio between the corresponding luma plane number of pixels and the current
2519 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2520 @code{0.5,0.5} for chroma planes.
2523 Time of the current frame, expressed in seconds.
2526 Value of pixel component at current location for first video frame (top layer).
2529 Value of pixel component at current location for second video frame (bottom layer).
2533 Force termination when the shortest input terminates. Default is @code{0}.
2535 Continue applying the last bottom frame after the end of the stream. A value of
2536 @code{0} disable the filter after the last frame of the bottom layer is reached.
2537 Default is @code{1}.
2540 @subsection Examples
2544 Apply transition from bottom layer to top layer in first 10 seconds:
2546 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2550 Apply 1x1 checkerboard effect:
2552 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2556 Apply uncover left effect:
2558 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2562 Apply uncover down effect:
2564 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2568 Apply uncover up-left effect:
2570 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2576 Apply boxblur algorithm to the input video.
2578 The filter accepts the following options:
2582 @item luma_radius, lr
2583 @item luma_power, lp
2584 @item chroma_radius, cr
2585 @item chroma_power, cp
2586 @item alpha_radius, ar
2587 @item alpha_power, ap
2591 A description of the accepted options follows.
2594 @item luma_radius, lr
2595 @item chroma_radius, cr
2596 @item alpha_radius, ar
2597 Set an expression for the box radius in pixels used for blurring the
2598 corresponding input plane.
2600 The radius value must be a non-negative number, and must not be
2601 greater than the value of the expression @code{min(w,h)/2} for the
2602 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2605 Default value for @option{luma_radius} is "2". If not specified,
2606 @option{chroma_radius} and @option{alpha_radius} default to the
2607 corresponding value set for @option{luma_radius}.
2609 The expressions can contain the following constants:
2613 the input width and height in pixels
2617 the input chroma image width and height in pixels
2621 horizontal and vertical chroma subsample values. For example for the
2622 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2625 @item luma_power, lp
2626 @item chroma_power, cp
2627 @item alpha_power, ap
2628 Specify how many times the boxblur filter is applied to the
2629 corresponding plane.
2631 Default value for @option{luma_power} is 2. If not specified,
2632 @option{chroma_power} and @option{alpha_power} default to the
2633 corresponding value set for @option{luma_power}.
2635 A value of 0 will disable the effect.
2638 @subsection Examples
2642 Apply a boxblur filter with luma, chroma, and alpha radius
2645 boxblur=luma_radius=2:luma_power=1
2650 Set luma radius to 2, alpha and chroma radius to 0:
2652 boxblur=2:1:cr=0:ar=0
2656 Set luma and chroma radius to a fraction of the video dimension:
2658 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2662 @section colorbalance
2663 Modify intensity of primary colors (red, green and blue) of input frames.
2665 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2666 regions for the red-cyan, green-magenta or blue-yellow balance.
2668 A positive adjustment value shifts the balance towards the primary color, a negative
2669 value towards the complementary color.
2671 The filter accepts the following options:
2677 Adjust red, green and blue shadows (darkest pixels).
2682 Adjust red, green and blue midtones (medium pixels).
2687 Adjust red, green and blue highlights (brightest pixels).
2689 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2692 @subsection Examples
2696 Add red color cast to shadows:
2702 @section colorchannelmixer
2704 Adjust video input frames by re-mixing color channels.
2706 This filter modifies a color channel by adding the values associated to
2707 the other channels of the same pixels. For example if the value to
2708 modify is red, the output value will be:
2710 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2713 The filter accepts the following options:
2720 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2721 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2727 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2728 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2734 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2735 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2741 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2742 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2744 Allowed ranges for options are @code{[-2.0, 2.0]}.
2747 @subsection Examples
2751 Convert source to grayscale:
2753 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2756 Simulate sepia tones:
2758 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
2762 @section colormatrix
2764 Convert color matrix.
2766 The filter accepts the following options:
2771 Specify the source and destination color matrix. Both values must be
2774 The accepted values are:
2790 For example to convert from BT.601 to SMPTE-240M, use the command:
2792 colormatrix=bt601:smpte240m
2797 Copy the input source unchanged to the output. Mainly useful for
2802 Crop the input video to given dimensions.
2804 The filter accepts the following options:
2808 Width of the output video. It defaults to @code{iw}.
2809 This expression is evaluated only once during the filter
2813 Height of the output video. It defaults to @code{ih}.
2814 This expression is evaluated only once during the filter
2818 Horizontal position, in the input video, of the left edge of the output video.
2819 It defaults to @code{(in_w-out_w)/2}.
2820 This expression is evaluated per-frame.
2823 Vertical position, in the input video, of the top edge of the output video.
2824 It defaults to @code{(in_h-out_h)/2}.
2825 This expression is evaluated per-frame.
2828 If set to 1 will force the output display aspect ratio
2829 to be the same of the input, by changing the output sample aspect
2830 ratio. It defaults to 0.
2833 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
2834 expressions containing the following constants:
2839 the computed values for @var{x} and @var{y}. They are evaluated for
2844 the input width and height
2848 same as @var{in_w} and @var{in_h}
2852 the output (cropped) width and height
2856 same as @var{out_w} and @var{out_h}
2859 same as @var{iw} / @var{ih}
2862 input sample aspect ratio
2865 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
2869 horizontal and vertical chroma subsample values. For example for the
2870 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2873 the number of input frame, starting from 0
2876 the position in the file of the input frame, NAN if unknown
2879 timestamp expressed in seconds, NAN if the input timestamp is unknown
2883 The expression for @var{out_w} may depend on the value of @var{out_h},
2884 and the expression for @var{out_h} may depend on @var{out_w}, but they
2885 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
2886 evaluated after @var{out_w} and @var{out_h}.
2888 The @var{x} and @var{y} parameters specify the expressions for the
2889 position of the top-left corner of the output (non-cropped) area. They
2890 are evaluated for each frame. If the evaluated value is not valid, it
2891 is approximated to the nearest valid value.
2893 The expression for @var{x} may depend on @var{y}, and the expression
2894 for @var{y} may depend on @var{x}.
2896 @subsection Examples
2900 Crop area with size 100x100 at position (12,34).
2905 Using named options, the example above becomes:
2907 crop=w=100:h=100:x=12:y=34
2911 Crop the central input area with size 100x100:
2917 Crop the central input area with size 2/3 of the input video:
2919 crop=2/3*in_w:2/3*in_h
2923 Crop the input video central square:
2930 Delimit the rectangle with the top-left corner placed at position
2931 100:100 and the right-bottom corner corresponding to the right-bottom
2932 corner of the input image:
2934 crop=in_w-100:in_h-100:100:100
2938 Crop 10 pixels from the left and right borders, and 20 pixels from
2939 the top and bottom borders
2941 crop=in_w-2*10:in_h-2*20
2945 Keep only the bottom right quarter of the input image:
2947 crop=in_w/2:in_h/2:in_w/2:in_h/2
2951 Crop height for getting Greek harmony:
2953 crop=in_w:1/PHI*in_w
2957 Appply trembling effect:
2959 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)
2963 Apply erratic camera effect depending on timestamp:
2965 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)"
2969 Set x depending on the value of y:
2971 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
2977 Auto-detect crop size.
2979 Calculate necessary cropping parameters and prints the recommended
2980 parameters through the logging system. The detected dimensions
2981 correspond to the non-black area of the input video.
2983 The filter accepts the following options:
2988 Set higher black value threshold, which can be optionally specified
2989 from nothing (0) to everything (255). An intensity value greater
2990 to the set value is considered non-black. Default value is 24.
2993 Set the value for which the width/height should be divisible by. The
2994 offset is automatically adjusted to center the video. Use 2 to get
2995 only even dimensions (needed for 4:2:2 video). 16 is best when
2996 encoding to most video codecs. Default value is 16.
2998 @item reset_count, reset
2999 Set the counter that determines after how many frames cropdetect will
3000 reset the previously detected largest video area and start over to
3001 detect the current optimal crop area. Default value is 0.
3003 This can be useful when channel logos distort the video area. 0
3004 indicates never reset and return the largest area encountered during
3011 Apply color adjustments using curves.
3013 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3014 component (red, green and blue) has its values defined by @var{N} key points
3015 tied from each other using a smooth curve. The x-axis represents the pixel
3016 values from the input frame, and the y-axis the new pixel values to be set for
3019 By default, a component curve is defined by the two points @var{(0;0)} and
3020 @var{(1;1)}. This creates a straight line where each original pixel value is
3021 "adjusted" to its own value, which means no change to the image.
3023 The filter allows you to redefine these two points and add some more. A new
3024 curve (using a natural cubic spline interpolation) will be define to pass
3025 smoothly through all these new coordinates. The new defined points needs to be
3026 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3027 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3028 the vector spaces, the values will be clipped accordingly.
3030 If there is no key point defined in @code{x=0}, the filter will automatically
3031 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3032 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3034 The filter accepts the following options:
3038 Select one of the available color presets. This option can be used in addition
3039 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3040 options takes priority on the preset values.
3041 Available presets are:
3044 @item color_negative
3047 @item increase_contrast
3049 @item linear_contrast
3050 @item medium_contrast
3052 @item strong_contrast
3055 Default is @code{none}.
3057 Set the master key points. These points will define a second pass mapping. It
3058 is sometimes called a "luminance" or "value" mapping. It can be used with
3059 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3060 post-processing LUT.
3062 Set the key points for the red component.
3064 Set the key points for the green component.
3066 Set the key points for the blue component.
3068 Set the key points for all components (not including master).
3069 Can be used in addition to the other key points component
3070 options. In this case, the unset component(s) will fallback on this
3071 @option{all} setting.
3073 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3076 To avoid some filtergraph syntax conflicts, each key points list need to be
3077 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3079 @subsection Examples
3083 Increase slightly the middle level of blue:
3085 curves=blue='0.5/0.58'
3091 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3093 Here we obtain the following coordinates for each components:
3096 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3098 @code{(0;0) (0.50;0.48) (1;1)}
3100 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3104 The previous example can also be achieved with the associated built-in preset:
3106 curves=preset=vintage
3116 Use a Photoshop preset and redefine the points of the green component:
3118 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3124 Denoise frames using 2D DCT (frequency domain filtering).
3126 This filter is not designed for real time and can be extremely slow.
3128 The filter accepts the following options:
3132 Set the noise sigma constant.
3134 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3135 coefficient (absolute value) below this threshold with be dropped.
3137 If you need a more advanced filtering, see @option{expr}.
3139 Default is @code{0}.
3142 Set number overlapping pixels for each block. Each block is of size
3143 @code{16x16}. Since the filter can be slow, you may want to reduce this value,
3144 at the cost of a less effective filter and the risk of various artefacts.
3146 If the overlapping value doesn't allow to process the whole input width or
3147 height, a warning will be displayed and according borders won't be denoised.
3149 Default value is @code{15}.
3152 Set the coefficient factor expression.
3154 For each coefficient of a DCT block, this expression will be evaluated as a
3155 multiplier value for the coefficient.
3157 If this is option is set, the @option{sigma} option will be ignored.
3159 The absolute value of the coefficient can be accessed through the @var{c}
3163 @subsection Examples
3165 Apply a denoise with a @option{sigma} of @code{4.5}:
3170 The same operation can be achieved using the expression system:
3172 dctdnoiz=e='gte(c, 4.5*3)'
3178 Drop duplicated frames at regular intervals.
3180 The filter accepts the following options:
3184 Set the number of frames from which one will be dropped. Setting this to
3185 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3186 Default is @code{5}.
3189 Set the threshold for duplicate detection. If the difference metric for a frame
3190 is less than or equal to this value, then it is declared as duplicate. Default
3194 Set scene change threshold. Default is @code{15}.
3198 Set the size of the x and y-axis blocks used during metric calculations.
3199 Larger blocks give better noise suppression, but also give worse detection of
3200 small movements. Must be a power of two. Default is @code{32}.
3203 Mark main input as a pre-processed input and activate clean source input
3204 stream. This allows the input to be pre-processed with various filters to help
3205 the metrics calculation while keeping the frame selection lossless. When set to
3206 @code{1}, the first stream is for the pre-processed input, and the second
3207 stream is the clean source from where the kept frames are chosen. Default is
3211 Set whether or not chroma is considered in the metric calculations. Default is
3217 Remove judder produced by partially interlaced telecined content.
3219 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3220 source was partially telecined content then the output of @code{pullup,dejudder}
3221 will have a variable frame rate. May change the recorded frame rate of the
3222 container. Aside from that change, this filter will not affect constant frame
3225 The option available in this filter is:
3229 Specify the length of the window over which the judder repeats.
3231 Accepts any interger greater than 1. Useful values are:
3235 If the original was telecined from 24 to 30 fps (Film to NTSC).
3238 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3241 If a mixture of the two.
3244 The default is @samp{4}.
3249 Suppress a TV station logo by a simple interpolation of the surrounding
3250 pixels. Just set a rectangle covering the logo and watch it disappear
3251 (and sometimes something even uglier appear - your mileage may vary).
3253 This filter accepts the following options:
3258 Specify the top left corner coordinates of the logo. They must be
3263 Specify the width and height of the logo to clear. They must be
3267 Specify the thickness of the fuzzy edge of the rectangle (added to
3268 @var{w} and @var{h}). The default value is 4.
3271 When set to 1, a green rectangle is drawn on the screen to simplify
3272 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3273 The default value is 0.
3275 The rectangle is drawn on the outermost pixels which will be (partly)
3276 replaced with interpolated values. The values of the next pixels
3277 immediately outside this rectangle in each direction will be used to
3278 compute the interpolated pixel values inside the rectangle.
3282 @subsection Examples
3286 Set a rectangle covering the area with top left corner coordinates 0,0
3287 and size 100x77, setting a band of size 10:
3289 delogo=x=0:y=0:w=100:h=77:band=10
3296 Attempt to fix small changes in horizontal and/or vertical shift. This
3297 filter helps remove camera shake from hand-holding a camera, bumping a
3298 tripod, moving on a vehicle, etc.
3300 The filter accepts the following options:
3308 Specify a rectangular area where to limit the search for motion
3310 If desired the search for motion vectors can be limited to a
3311 rectangular area of the frame defined by its top left corner, width
3312 and height. These parameters have the same meaning as the drawbox
3313 filter which can be used to visualise the position of the bounding
3316 This is useful when simultaneous movement of subjects within the frame
3317 might be confused for camera motion by the motion vector search.
3319 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3320 then the full frame is used. This allows later options to be set
3321 without specifying the bounding box for the motion vector search.
3323 Default - search the whole frame.
3327 Specify the maximum extent of movement in x and y directions in the
3328 range 0-64 pixels. Default 16.
3331 Specify how to generate pixels to fill blanks at the edge of the
3332 frame. Available values are:
3335 Fill zeroes at blank locations
3337 Original image at blank locations
3339 Extruded edge value at blank locations
3341 Mirrored edge at blank locations
3343 Default value is @samp{mirror}.
3346 Specify the blocksize to use for motion search. Range 4-128 pixels,
3350 Specify the contrast threshold for blocks. Only blocks with more than
3351 the specified contrast (difference between darkest and lightest
3352 pixels) will be considered. Range 1-255, default 125.
3355 Specify the search strategy. Available values are:
3358 Set exhaustive search
3360 Set less exhaustive search.
3362 Default value is @samp{exhaustive}.
3365 If set then a detailed log of the motion search is written to the
3369 If set to 1, specify using OpenCL capabilities, only available if
3370 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3376 Draw a colored box on the input image.
3378 This filter accepts the following options:
3383 The expressions which specify the top left corner coordinates of the box. Default to 0.
3387 The expressions which specify the width and height of the box, if 0 they are interpreted as
3388 the input width and height. Default to 0.
3391 Specify the color of the box to write. For the general syntax of this option,
3392 check the "Color" section in the ffmpeg-utils manual. If the special
3393 value @code{invert} is used, the box edge color is the same as the
3394 video with inverted luma.
3397 The expression which sets the thickness of the box edge. Default value is @code{3}.
3399 See below for the list of accepted constants.
3402 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3403 following constants:
3407 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3411 horizontal and vertical chroma subsample values. For example for the
3412 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3416 The input width and height.
3419 The input sample aspect ratio.
3423 The x and y offset coordinates where the box is drawn.
3427 The width and height of the drawn box.
3430 The thickness of the drawn box.
3432 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3433 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3437 @subsection Examples
3441 Draw a black box around the edge of the input image:
3447 Draw a box with color red and an opacity of 50%:
3449 drawbox=10:20:200:60:red@@0.5
3452 The previous example can be specified as:
3454 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3458 Fill the box with pink color:
3460 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3464 Draw a 2-pixel red 2.40:1 mask:
3466 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
3472 Draw a grid on the input image.
3474 This filter accepts the following options:
3479 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3483 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3484 input width and height, respectively, minus @code{thickness}, so image gets
3485 framed. Default to 0.
3488 Specify the color of the grid. For the general syntax of this option,
3489 check the "Color" section in the ffmpeg-utils manual. If the special
3490 value @code{invert} is used, the grid color is the same as the
3491 video with inverted luma.
3494 The expression which sets the thickness of the grid line. Default value is @code{1}.
3496 See below for the list of accepted constants.
3499 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3500 following constants:
3504 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3508 horizontal and vertical chroma subsample values. For example for the
3509 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3513 The input grid cell width and height.
3516 The input sample aspect ratio.
3520 The x and y coordinates of some point of grid intersection (meant to configure offset).
3524 The width and height of the drawn cell.
3527 The thickness of the drawn cell.
3529 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3530 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3534 @subsection Examples
3538 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3540 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3544 Draw a white 3x3 grid with an opacity of 50%:
3546 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3553 Draw text string or text from specified file on top of video using the
3554 libfreetype library.
3556 To enable compilation of this filter you need to configure FFmpeg with
3557 @code{--enable-libfreetype}.
3561 The description of the accepted parameters follows.
3566 Used to draw a box around text using background color.
3567 Value should be either 1 (enable) or 0 (disable).
3568 The default value of @var{box} is 0.
3571 The color to be used for drawing box around text. For the syntax of this
3572 option, check the "Color" section in the ffmpeg-utils manual.
3574 The default value of @var{boxcolor} is "white".
3577 Set the width of the border to be drawn around the text using @var{bordercolor}.
3578 The default value of @var{borderw} is 0.
3581 Set the color to be used for drawing border around text. For the syntax of this
3582 option, check the "Color" section in the ffmpeg-utils manual.
3584 The default value of @var{bordercolor} is "black".
3587 Select how the @var{text} is expanded. Can be either @code{none},
3588 @code{strftime} (deprecated) or
3589 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3593 If true, check and fix text coords to avoid clipping.
3596 The color to be used for drawing fonts. For the syntax of this option, check
3597 the "Color" section in the ffmpeg-utils manual.
3599 The default value of @var{fontcolor} is "black".
3602 The font file to be used for drawing text. Path must be included.
3603 This parameter is mandatory.
3606 The font size to be used for drawing text.
3607 The default value of @var{fontsize} is 16.
3610 Flags to be used for loading the fonts.
3612 The flags map the corresponding flags supported by libfreetype, and are
3613 a combination of the following values:
3620 @item vertical_layout
3621 @item force_autohint
3624 @item ignore_global_advance_width
3626 @item ignore_transform
3632 Default value is "default".
3634 For more information consult the documentation for the FT_LOAD_*
3638 The color to be used for drawing a shadow behind the drawn text. For the
3639 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3641 The default value of @var{shadowcolor} is "black".
3645 The x and y offsets for the text shadow position with respect to the
3646 position of the text. They can be either positive or negative
3647 values. Default value for both is "0".
3650 The starting frame number for the n/frame_num variable. The default value
3654 The size in number of spaces to use for rendering the tab.
3658 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3659 format. It can be used with or without text parameter. @var{timecode_rate}
3660 option must be specified.
3662 @item timecode_rate, rate, r
3663 Set the timecode frame rate (timecode only).
3666 The text string to be drawn. The text must be a sequence of UTF-8
3668 This parameter is mandatory if no file is specified with the parameter
3672 A text file containing text to be drawn. The text must be a sequence
3673 of UTF-8 encoded characters.
3675 This parameter is mandatory if no text string is specified with the
3676 parameter @var{text}.
3678 If both @var{text} and @var{textfile} are specified, an error is thrown.
3681 If set to 1, the @var{textfile} will be reloaded before each frame.
3682 Be sure to update it atomically, or it may be read partially, or even fail.
3686 The expressions which specify the offsets where text will be drawn
3687 within the video frame. They are relative to the top/left border of the
3690 The default value of @var{x} and @var{y} is "0".
3692 See below for the list of accepted constants and functions.
3695 The parameters for @var{x} and @var{y} are expressions containing the
3696 following constants and functions:
3700 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3704 horizontal and vertical chroma subsample values. For example for the
3705 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3708 the height of each text line
3716 @item max_glyph_a, ascent
3717 the maximum distance from the baseline to the highest/upper grid
3718 coordinate used to place a glyph outline point, for all the rendered
3720 It is a positive value, due to the grid's orientation with the Y axis
3723 @item max_glyph_d, descent
3724 the maximum distance from the baseline to the lowest grid coordinate
3725 used to place a glyph outline point, for all the rendered glyphs.
3726 This is a negative value, due to the grid's orientation, with the Y axis
3730 maximum glyph height, that is the maximum height for all the glyphs
3731 contained in the rendered text, it is equivalent to @var{ascent} -
3735 maximum glyph width, that is the maximum width for all the glyphs
3736 contained in the rendered text
3739 the number of input frame, starting from 0
3741 @item rand(min, max)
3742 return a random number included between @var{min} and @var{max}
3745 input sample aspect ratio
3748 timestamp expressed in seconds, NAN if the input timestamp is unknown
3751 the height of the rendered text
3754 the width of the rendered text
3758 the x and y offset coordinates where the text is drawn.
3760 These parameters allow the @var{x} and @var{y} expressions to refer
3761 each other, so you can for example specify @code{y=x/dar}.
3764 If libavfilter was built with @code{--enable-fontconfig}, then
3765 @option{fontfile} can be a fontconfig pattern or omitted.
3767 @anchor{drawtext_expansion}
3768 @subsection Text expansion
3770 If @option{expansion} is set to @code{strftime},
3771 the filter recognizes strftime() sequences in the provided text and
3772 expands them accordingly. Check the documentation of strftime(). This
3773 feature is deprecated.
3775 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3777 If @option{expansion} is set to @code{normal} (which is the default),
3778 the following expansion mechanism is used.
3780 The backslash character '\', followed by any character, always expands to
3781 the second character.
3783 Sequence of the form @code{%@{...@}} are expanded. The text between the
3784 braces is a function name, possibly followed by arguments separated by ':'.
3785 If the arguments contain special characters or delimiters (':' or '@}'),
3786 they should be escaped.
3788 Note that they probably must also be escaped as the value for the
3789 @option{text} option in the filter argument string and as the filter
3790 argument in the filtergraph description, and possibly also for the shell,
3791 that makes up to four levels of escaping; using a text file avoids these
3794 The following functions are available:
3799 The expression evaluation result.
3801 It must take one argument specifying the expression to be evaluated,
3802 which accepts the same constants and functions as the @var{x} and
3803 @var{y} values. Note that not all constants should be used, for
3804 example the text size is not known when evaluating the expression, so
3805 the constants @var{text_w} and @var{text_h} will have an undefined
3809 The time at which the filter is running, expressed in UTC.
3810 It can accept an argument: a strftime() format string.
3813 The time at which the filter is running, expressed in the local time zone.
3814 It can accept an argument: a strftime() format string.
3817 Frame metadata. It must take one argument specifying metadata key.
3820 The frame number, starting from 0.
3823 A 1 character description of the current picture type.
3826 The timestamp of the current frame, in seconds, with microsecond accuracy.
3830 @subsection Examples
3834 Draw "Test Text" with font FreeSerif, using the default values for the
3835 optional parameters.
3838 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
3842 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
3843 and y=50 (counting from the top-left corner of the screen), text is
3844 yellow with a red box around it. Both the text and the box have an
3848 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
3849 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
3852 Note that the double quotes are not necessary if spaces are not used
3853 within the parameter list.
3856 Show the text at the center of the video frame:
3858 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
3862 Show a text line sliding from right to left in the last row of the video
3863 frame. The file @file{LONG_LINE} is assumed to contain a single line
3866 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
3870 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
3872 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
3876 Draw a single green letter "g", at the center of the input video.
3877 The glyph baseline is placed at half screen height.
3879 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
3883 Show text for 1 second every 3 seconds:
3885 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
3889 Use fontconfig to set the font. Note that the colons need to be escaped.
3891 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
3895 Print the date of a real-time encoding (see strftime(3)):
3897 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
3902 For more information about libfreetype, check:
3903 @url{http://www.freetype.org/}.
3905 For more information about fontconfig, check:
3906 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
3910 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
3912 The filter accepts the following options:
3917 Set low and high threshold values used by the Canny thresholding
3920 The high threshold selects the "strong" edge pixels, which are then
3921 connected through 8-connectivity with the "weak" edge pixels selected
3922 by the low threshold.
3924 @var{low} and @var{high} threshold values must be chosen in the range
3925 [0,1], and @var{low} should be lesser or equal to @var{high}.
3927 Default value for @var{low} is @code{20/255}, and default value for @var{high}
3933 edgedetect=low=0.1:high=0.4
3936 @section extractplanes
3938 Extract color channel components from input video stream into
3939 separate grayscale video streams.
3941 The filter accepts the following option:
3945 Set plane(s) to extract.
3947 Available values for planes are:
3958 Choosing planes not available in the input will result in an error.
3959 That means you cannot select @code{r}, @code{g}, @code{b} planes
3960 with @code{y}, @code{u}, @code{v} planes at same time.
3963 @subsection Examples
3967 Extract luma, u and v color channel component from input video frame
3968 into 3 grayscale outputs:
3970 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
3976 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
3978 For each input image, the filter will compute the optimal mapping from
3979 the input to the output given the codebook length, that is the number
3980 of distinct output colors.
3982 This filter accepts the following options.
3985 @item codebook_length, l
3986 Set codebook length. The value must be a positive integer, and
3987 represents the number of distinct output colors. Default value is 256.
3990 Set the maximum number of iterations to apply for computing the optimal
3991 mapping. The higher the value the better the result and the higher the
3992 computation time. Default value is 1.
3995 Set a random seed, must be an integer included between 0 and
3996 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
3997 will try to use a good random seed on a best effort basis.
4002 Apply fade-in/out effect to input video.
4004 This filter accepts the following options:
4008 The effect type -- can be either "in" for fade-in, or "out" for a fade-out
4010 Default is @code{in}.
4012 @item start_frame, s
4013 Specify the number of the start frame for starting to apply the fade
4014 effect. Default is 0.
4017 The number of frames for which the fade effect has to last. At the end of the
4018 fade-in effect the output video will have the same intensity as the input video,
4019 at the end of the fade-out transition the output video will be filled with the
4020 selected @option{color}.
4024 If set to 1, fade only alpha channel, if one exists on the input.
4027 @item start_time, st
4028 Specify the timestamp (in seconds) of the frame to start to apply the fade
4029 effect. If both start_frame and start_time are specified, the fade will start at
4030 whichever comes last. Default is 0.
4033 The number of seconds for which the fade effect has to last. At the end of the
4034 fade-in effect the output video will have the same intensity as the input video,
4035 at the end of the fade-out transition the output video will be filled with the
4036 selected @option{color}.
4037 If both duration and nb_frames are specified, duration is used. Default is 0.
4040 Specify the color of the fade. Default is "black".
4043 @subsection Examples
4047 Fade in first 30 frames of video:
4052 The command above is equivalent to:
4058 Fade out last 45 frames of a 200-frame video:
4061 fade=type=out:start_frame=155:nb_frames=45
4065 Fade in first 25 frames and fade out last 25 frames of a 1000-frame video:
4067 fade=in:0:25, fade=out:975:25
4071 Make first 5 frames yellow, then fade in from frame 5-24:
4073 fade=in:5:20:color=yellow
4077 Fade in alpha over first 25 frames of video:
4079 fade=in:0:25:alpha=1
4083 Make first 5.5 seconds black, then fade in for 0.5 seconds:
4085 fade=t=in:st=5.5:d=0.5
4092 Extract a single field from an interlaced image using stride
4093 arithmetic to avoid wasting CPU time. The output frames are marked as
4096 The filter accepts the following options:
4100 Specify whether to extract the top (if the value is @code{0} or
4101 @code{top}) or the bottom field (if the value is @code{1} or
4107 Field matching filter for inverse telecine. It is meant to reconstruct the
4108 progressive frames from a telecined stream. The filter does not drop duplicated
4109 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4110 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4112 The separation of the field matching and the decimation is notably motivated by
4113 the possibility of inserting a de-interlacing filter fallback between the two.
4114 If the source has mixed telecined and real interlaced content,
4115 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4116 But these remaining combed frames will be marked as interlaced, and thus can be
4117 de-interlaced by a later filter such as @ref{yadif} before decimation.
4119 In addition to the various configuration options, @code{fieldmatch} can take an
4120 optional second stream, activated through the @option{ppsrc} option. If
4121 enabled, the frames reconstruction will be based on the fields and frames from
4122 this second stream. This allows the first input to be pre-processed in order to
4123 help the various algorithms of the filter, while keeping the output lossless
4124 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4125 or brightness/contrast adjustments can help.
4127 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4128 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4129 which @code{fieldmatch} is based on. While the semantic and usage are very
4130 close, some behaviour and options names can differ.
4132 The filter accepts the following options:
4136 Specify the assumed field order of the input stream. Available values are:
4140 Auto detect parity (use FFmpeg's internal parity value).
4142 Assume bottom field first.
4144 Assume top field first.
4147 Note that it is sometimes recommended not to trust the parity announced by the
4150 Default value is @var{auto}.
4153 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4154 sense that it won't risk creating jerkiness due to duplicate frames when
4155 possible, but if there are bad edits or blended fields it will end up
4156 outputting combed frames when a good match might actually exist. On the other
4157 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4158 but will almost always find a good frame if there is one. The other values are
4159 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4160 jerkiness and creating duplicate frames versus finding good matches in sections
4161 with bad edits, orphaned fields, blended fields, etc.
4163 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4165 Available values are:
4169 2-way matching (p/c)
4171 2-way matching, and trying 3rd match if still combed (p/c + n)
4173 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4175 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4176 still combed (p/c + n + u/b)
4178 3-way matching (p/c/n)
4180 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4181 detected as combed (p/c/n + u/b)
4184 The parenthesis at the end indicate the matches that would be used for that
4185 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4188 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4191 Default value is @var{pc_n}.
4194 Mark the main input stream as a pre-processed input, and enable the secondary
4195 input stream as the clean source to pick the fields from. See the filter
4196 introduction for more details. It is similar to the @option{clip2} feature from
4199 Default value is @code{0} (disabled).
4202 Set the field to match from. It is recommended to set this to the same value as
4203 @option{order} unless you experience matching failures with that setting. In
4204 certain circumstances changing the field that is used to match from can have a
4205 large impact on matching performance. Available values are:
4209 Automatic (same value as @option{order}).
4211 Match from the bottom field.
4213 Match from the top field.
4216 Default value is @var{auto}.
4219 Set whether or not chroma is included during the match comparisons. In most
4220 cases it is recommended to leave this enabled. You should set this to @code{0}
4221 only if your clip has bad chroma problems such as heavy rainbowing or other
4222 artifacts. Setting this to @code{0} could also be used to speed things up at
4223 the cost of some accuracy.
4225 Default value is @code{1}.
4229 These define an exclusion band which excludes the lines between @option{y0} and
4230 @option{y1} from being included in the field matching decision. An exclusion
4231 band can be used to ignore subtitles, a logo, or other things that may
4232 interfere with the matching. @option{y0} sets the starting scan line and
4233 @option{y1} sets the ending line; all lines in between @option{y0} and
4234 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4235 @option{y0} and @option{y1} to the same value will disable the feature.
4236 @option{y0} and @option{y1} defaults to @code{0}.
4239 Set the scene change detection threshold as a percentage of maximum change on
4240 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4241 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4242 @option{scthresh} is @code{[0.0, 100.0]}.
4244 Default value is @code{12.0}.
4247 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4248 account the combed scores of matches when deciding what match to use as the
4249 final match. Available values are:
4253 No final matching based on combed scores.
4255 Combed scores are only used when a scene change is detected.
4257 Use combed scores all the time.
4260 Default is @var{sc}.
4263 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4264 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4265 Available values are:
4269 No forced calculation.
4271 Force p/c/n calculations.
4273 Force p/c/n/u/b calculations.
4276 Default value is @var{none}.
4279 This is the area combing threshold used for combed frame detection. This
4280 essentially controls how "strong" or "visible" combing must be to be detected.
4281 Larger values mean combing must be more visible and smaller values mean combing
4282 can be less visible or strong and still be detected. Valid settings are from
4283 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4284 be detected as combed). This is basically a pixel difference value. A good
4285 range is @code{[8, 12]}.
4287 Default value is @code{9}.
4290 Sets whether or not chroma is considered in the combed frame decision. Only
4291 disable this if your source has chroma problems (rainbowing, etc.) that are
4292 causing problems for the combed frame detection with chroma enabled. Actually,
4293 using @option{chroma}=@var{0} is usually more reliable, except for the case
4294 where there is chroma only combing in the source.
4296 Default value is @code{0}.
4300 Respectively set the x-axis and y-axis size of the window used during combed
4301 frame detection. This has to do with the size of the area in which
4302 @option{combpel} pixels are required to be detected as combed for a frame to be
4303 declared combed. See the @option{combpel} parameter description for more info.
4304 Possible values are any number that is a power of 2 starting at 4 and going up
4307 Default value is @code{16}.
4310 The number of combed pixels inside any of the @option{blocky} by
4311 @option{blockx} size blocks on the frame for the frame to be detected as
4312 combed. While @option{cthresh} controls how "visible" the combing must be, this
4313 setting controls "how much" combing there must be in any localized area (a
4314 window defined by the @option{blockx} and @option{blocky} settings) on the
4315 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4316 which point no frames will ever be detected as combed). This setting is known
4317 as @option{MI} in TFM/VFM vocabulary.
4319 Default value is @code{80}.
4322 @anchor{p/c/n/u/b meaning}
4323 @subsection p/c/n/u/b meaning
4325 @subsubsection p/c/n
4327 We assume the following telecined stream:
4330 Top fields: 1 2 2 3 4
4331 Bottom fields: 1 2 3 4 4
4334 The numbers correspond to the progressive frame the fields relate to. Here, the
4335 first two frames are progressive, the 3rd and 4th are combed, and so on.
4337 When @code{fieldmatch} is configured to run a matching from bottom
4338 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4343 B 1 2 3 4 4 <-- matching reference
4352 As a result of the field matching, we can see that some frames get duplicated.
4353 To perform a complete inverse telecine, you need to rely on a decimation filter
4354 after this operation. See for instance the @ref{decimate} filter.
4356 The same operation now matching from top fields (@option{field}=@var{top})
4361 T 1 2 2 3 4 <-- matching reference
4371 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4372 basically, they refer to the frame and field of the opposite parity:
4375 @item @var{p} matches the field of the opposite parity in the previous frame
4376 @item @var{c} matches the field of the opposite parity in the current frame
4377 @item @var{n} matches the field of the opposite parity in the next frame
4382 The @var{u} and @var{b} matching are a bit special in the sense that they match
4383 from the opposite parity flag. In the following examples, we assume that we are
4384 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4385 'x' is placed above and below each matched fields.
4387 With bottom matching (@option{field}=@var{bottom}):
4392 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4393 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4401 With top matching (@option{field}=@var{top}):
4406 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4407 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4415 @subsection Examples
4417 Simple IVTC of a top field first telecined stream:
4419 fieldmatch=order=tff:combmatch=none, decimate
4422 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4424 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4429 Transform the field order of the input video.
4431 This filter accepts the following options:
4436 Output field order. Valid values are @var{tff} for top field first or @var{bff}
4437 for bottom field first.
4440 Default value is @samp{tff}.
4442 Transformation is achieved by shifting the picture content up or down
4443 by one line, and filling the remaining line with appropriate picture content.
4444 This method is consistent with most broadcast field order converters.
4446 If the input video is not flagged as being interlaced, or it is already
4447 flagged as being of the required output field order then this filter does
4448 not alter the incoming video.
4450 This filter is very useful when converting to or from PAL DV material,
4451 which is bottom field first.
4455 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4460 Buffer input images and send them when they are requested.
4462 This filter is mainly useful when auto-inserted by the libavfilter
4465 The filter does not take parameters.
4470 Convert the input video to one of the specified pixel formats.
4471 Libavfilter will try to pick one that is supported for the input to
4474 This filter accepts the following parameters:
4478 A '|'-separated list of pixel format names, for example
4479 "pix_fmts=yuv420p|monow|rgb24".
4483 @subsection Examples
4487 Convert the input video to the format @var{yuv420p}
4489 format=pix_fmts=yuv420p
4492 Convert the input video to any of the formats in the list
4494 format=pix_fmts=yuv420p|yuv444p|yuv410p
4501 Convert the video to specified constant frame rate by duplicating or dropping
4502 frames as necessary.
4504 This filter accepts the following named parameters:
4508 Desired output frame rate. The default is @code{25}.
4513 Possible values are:
4516 zero round towards 0
4520 round towards -infinity
4522 round towards +infinity
4526 The default is @code{near}.
4529 Assume the first PTS should be the given value, in seconds. This allows for
4530 padding/trimming at the start of stream. By default, no assumption is made
4531 about the first frame's expected PTS, so no padding or trimming is done.
4532 For example, this could be set to 0 to pad the beginning with duplicates of
4533 the first frame if a video stream starts after the audio stream or to trim any
4534 frames with a negative PTS.
4538 Alternatively, the options can be specified as a flat string:
4539 @var{fps}[:@var{round}].
4541 See also the @ref{setpts} filter.
4543 @subsection Examples
4547 A typical usage in order to set the fps to 25:
4553 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4555 fps=fps=film:round=near
4561 Pack two different video streams into a stereoscopic video, setting proper
4562 metadata on supported codecs. The two views should have the same size and
4563 framerate and processing will stop when the shorter video ends. Please note
4564 that you may conveniently adjust view properties with the @ref{scale} and
4567 This filter accepts the following named parameters:
4571 Desired packing format. Supported values are:
4576 Views are next to each other (default).
4579 Views are on top of each other.
4582 Views are packed by line.
4585 Views are eacked by column.
4588 Views are temporally interleaved.
4594 Some examples follow:
4597 # Convert left and right views into a frame sequential video.
4598 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
4600 # Convert views into a side-by-side video with the same output resolution as the input.
4601 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
4606 Select one frame every N-th frame.
4608 This filter accepts the following option:
4611 Select frame after every @code{step} frames.
4612 Allowed values are positive integers higher than 0. Default value is @code{1}.
4618 Apply a frei0r effect to the input video.
4620 To enable compilation of this filter you need to install the frei0r
4621 header and configure FFmpeg with @code{--enable-frei0r}.
4623 This filter accepts the following options:
4628 The name to the frei0r effect to load. If the environment variable
4629 @env{FREI0R_PATH} is defined, the frei0r effect is searched in each one of the
4630 directories specified by the colon separated list in @env{FREIOR_PATH},
4631 otherwise in the standard frei0r paths, which are in this order:
4632 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
4633 @file{/usr/lib/frei0r-1/}.
4636 A '|'-separated list of parameters to pass to the frei0r effect.
4640 A frei0r effect parameter can be a boolean (whose values are specified
4641 with "y" and "n"), a double, a color (specified by the syntax
4642 @var{R}/@var{G}/@var{B}, (@var{R}, @var{G}, and @var{B} being float
4643 numbers from 0.0 to 1.0) or by a color description specified in the "Color"
4644 section in the ffmpeg-utils manual), a position (specified by the syntax @var{X}/@var{Y},
4645 @var{X} and @var{Y} being float numbers) and a string.
4647 The number and kind of parameters depend on the loaded effect. If an
4648 effect parameter is not specified the default value is set.
4650 @subsection Examples
4654 Apply the distort0r effect, set the first two double parameters:
4656 frei0r=filter_name=distort0r:filter_params=0.5|0.01
4660 Apply the colordistance effect, take a color as first parameter:
4662 frei0r=colordistance:0.2/0.3/0.4
4663 frei0r=colordistance:violet
4664 frei0r=colordistance:0x112233
4668 Apply the perspective effect, specify the top left and top right image
4671 frei0r=perspective:0.2/0.2|0.8/0.2
4675 For more information see:
4676 @url{http://frei0r.dyne.org}
4680 The filter accepts the following options:
4684 Set the luminance expression.
4686 Set the chrominance blue expression.
4688 Set the chrominance red expression.
4690 Set the alpha expression.
4692 Set the red expression.
4694 Set the green expression.
4696 Set the blue expression.
4699 The colorspace is selected according to the specified options. If one
4700 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4701 options is specified, the filter will automatically select a YCbCr
4702 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4703 @option{blue_expr} options is specified, it will select an RGB
4706 If one of the chrominance expression is not defined, it falls back on the other
4707 one. If no alpha expression is specified it will evaluate to opaque value.
4708 If none of chrominance expressions are specified, they will evaluate
4709 to the luminance expression.
4711 The expressions can use the following variables and functions:
4715 The sequential number of the filtered frame, starting from @code{0}.
4719 The coordinates of the current sample.
4723 The width and height of the image.
4727 Width and height scale depending on the currently filtered plane. It is the
4728 ratio between the corresponding luma plane number of pixels and the current
4729 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4730 @code{0.5,0.5} for chroma planes.
4733 Time of the current frame, expressed in seconds.
4736 Return the value of the pixel at location (@var{x},@var{y}) of the current
4740 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
4744 Return the value of the pixel at location (@var{x},@var{y}) of the
4745 blue-difference chroma plane. Return 0 if there is no such plane.
4748 Return the value of the pixel at location (@var{x},@var{y}) of the
4749 red-difference chroma plane. Return 0 if there is no such plane.
4754 Return the value of the pixel at location (@var{x},@var{y}) of the
4755 red/green/blue component. Return 0 if there is no such component.
4758 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
4759 plane. Return 0 if there is no such plane.
4762 For functions, if @var{x} and @var{y} are outside the area, the value will be
4763 automatically clipped to the closer edge.
4765 @subsection Examples
4769 Flip the image horizontally:
4775 Generate a bidimensional sine wave, with angle @code{PI/3} and a
4776 wavelength of 100 pixels:
4778 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
4782 Generate a fancy enigmatic moving light:
4784 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
4788 Generate a quick emboss effect:
4790 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
4794 Modify RGB components depending on pixel position:
4796 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
4802 Fix the banding artifacts that are sometimes introduced into nearly flat
4803 regions by truncation to 8bit color depth.
4804 Interpolate the gradients that should go where the bands are, and
4807 This filter is designed for playback only. Do not use it prior to
4808 lossy compression, because compression tends to lose the dither and
4809 bring back the bands.
4811 This filter accepts the following options:
4816 The maximum amount by which the filter will change any one pixel. Also the
4817 threshold for detecting nearly flat regions. Acceptable values range from .51 to
4818 64, default value is 1.2, out-of-range values will be clipped to the valid
4822 The neighborhood to fit the gradient to. A larger radius makes for smoother
4823 gradients, but also prevents the filter from modifying the pixels near detailed
4824 regions. Acceptable values are 8-32, default value is 16, out-of-range values
4825 will be clipped to the valid range.
4829 Alternatively, the options can be specified as a flat string:
4830 @var{strength}[:@var{radius}]
4832 @subsection Examples
4836 Apply the filter with a @code{3.5} strength and radius of @code{8}:
4842 Specify radius, omitting the strength (which will fall-back to the default
4853 Apply a Hald CLUT to a video stream.
4855 First input is the video stream to process, and second one is the Hald CLUT.
4856 The Hald CLUT input can be a simple picture or a complete video stream.
4858 The filter accepts the following options:
4862 Force termination when the shortest input terminates. Default is @code{0}.
4864 Continue applying the last CLUT after the end of the stream. A value of
4865 @code{0} disable the filter after the last frame of the CLUT is reached.
4866 Default is @code{1}.
4869 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
4870 filters share the same internals).
4872 More information about the Hald CLUT can be found on Eskil Steenberg's website
4873 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
4875 @subsection Workflow examples
4877 @subsubsection Hald CLUT video stream
4879 Generate an identity Hald CLUT stream altered with various effects:
4881 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
4884 Note: make sure you use a lossless codec.
4886 Then use it with @code{haldclut} to apply it on some random stream:
4888 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
4891 The Hald CLUT will be applied to the 10 first seconds (duration of
4892 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
4893 to the remaining frames of the @code{mandelbrot} stream.
4895 @subsubsection Hald CLUT with preview
4897 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
4898 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
4899 biggest possible square starting at the top left of the picture. The remaining
4900 padding pixels (bottom or right) will be ignored. This area can be used to add
4901 a preview of the Hald CLUT.
4903 Typically, the following generated Hald CLUT will be supported by the
4904 @code{haldclut} filter:
4907 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
4908 pad=iw+320 [padded_clut];
4909 smptebars=s=320x256, split [a][b];
4910 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
4911 [main][b] overlay=W-320" -frames:v 1 clut.png
4914 It contains the original and a preview of the effect of the CLUT: SMPTE color
4915 bars are displayed on the right-top, and below the same color bars processed by
4918 Then, the effect of this Hald CLUT can be visualized with:
4920 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
4925 Flip the input video horizontally.
4927 For example to horizontally flip the input video with @command{ffmpeg}:
4929 ffmpeg -i in.avi -vf "hflip" out.avi
4933 This filter applies a global color histogram equalization on a
4936 It can be used to correct video that has a compressed range of pixel
4937 intensities. The filter redistributes the pixel intensities to
4938 equalize their distribution across the intensity range. It may be
4939 viewed as an "automatically adjusting contrast filter". This filter is
4940 useful only for correcting degraded or poorly captured source
4943 The filter accepts the following options:
4947 Determine the amount of equalization to be applied. As the strength
4948 is reduced, the distribution of pixel intensities more-and-more
4949 approaches that of the input frame. The value must be a float number
4950 in the range [0,1] and defaults to 0.200.
4953 Set the maximum intensity that can generated and scale the output
4954 values appropriately. The strength should be set as desired and then
4955 the intensity can be limited if needed to avoid washing-out. The value
4956 must be a float number in the range [0,1] and defaults to 0.210.
4959 Set the antibanding level. If enabled the filter will randomly vary
4960 the luminance of output pixels by a small amount to avoid banding of
4961 the histogram. Possible values are @code{none}, @code{weak} or
4962 @code{strong}. It defaults to @code{none}.
4967 Compute and draw a color distribution histogram for the input video.
4969 The computed histogram is a representation of the color component
4970 distribution in an image.
4972 The filter accepts the following options:
4978 It accepts the following values:
4981 Standard histogram that displays the color components distribution in an
4982 image. Displays color graph for each color component. Shows distribution of
4983 the Y, U, V, A or R, G, B components, depending on input format, in the
4984 current frame. Below each graph a color component scale meter is shown.
4987 Displays chroma values (U/V color placement) in a two dimensional
4988 graph (which is called a vectorscope). The brighter a pixel in the
4989 vectorscope, the more pixels of the input frame correspond to that pixel
4990 (i.e., more pixels have this chroma value). The V component is displayed on
4991 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
4992 side being V = 255. The U component is displayed on the vertical (Y) axis,
4993 with the top representing U = 0 and the bottom representing U = 255.
4995 The position of a white pixel in the graph corresponds to the chroma value of
4996 a pixel of the input clip. The graph can therefore be used to read the hue
4997 (color flavor) and the saturation (the dominance of the hue in the color). As
4998 the hue of a color changes, it moves around the square. At the center of the
4999 square the saturation is zero, which means that the corresponding pixel has no
5000 color. If the amount of a specific color is increased (while leaving the other
5001 colors unchanged) the saturation increases, and the indicator moves towards
5002 the edge of the square.
5005 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5009 Per row/column color component graph. In row mode, the graph on the left side
5010 represents color component value 0 and the right side represents value = 255.
5011 In column mode, the top side represents color component value = 0 and bottom
5012 side represents value = 255.
5014 Default value is @code{levels}.
5017 Set height of level in @code{levels}. Default value is @code{200}.
5018 Allowed range is [50, 2048].
5021 Set height of color scale in @code{levels}. Default value is @code{12}.
5022 Allowed range is [0, 40].
5025 Set step for @code{waveform} mode. Smaller values are useful to find out how
5026 many values of the same luminance are distributed across input rows/columns.
5027 Default value is @code{10}. Allowed range is [1, 255].
5030 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5031 Default is @code{row}.
5033 @item waveform_mirror
5034 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5035 means mirrored. In mirrored mode, higher values will be represented on the left
5036 side for @code{row} mode and at the top for @code{column} mode. Default is
5037 @code{0} (unmirrored).
5040 Set display mode for @code{waveform} and @code{levels}.
5041 It accepts the following values:
5044 Display separate graph for the color components side by side in
5045 @code{row} waveform mode or one below the other in @code{column} waveform mode
5046 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5047 per color component graphs are placed below each other.
5049 Using this display mode in @code{waveform} histogram mode makes it easy to
5050 spot color casts in the highlights and shadows of an image, by comparing the
5051 contours of the top and the bottom graphs of each waveform. Since whites,
5052 grays, and blacks are characterized by exactly equal amounts of red, green,
5053 and blue, neutral areas of the picture should display three waveforms of
5054 roughly equal width/height. If not, the correction is easy to perform by
5055 making level adjustments the three waveforms.
5058 Presents information identical to that in the @code{parade}, except
5059 that the graphs representing color components are superimposed directly
5062 This display mode in @code{waveform} histogram mode makes it easier to spot
5063 relative differences or similarities in overlapping areas of the color
5064 components that are supposed to be identical, such as neutral whites, grays,
5067 Default is @code{parade}.
5070 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5071 Default is @code{linear}.
5074 @subsection Examples
5079 Calculate and draw histogram:
5081 ffplay -i input -vf histogram
5089 High precision/quality 3d denoise filter. This filter aims to reduce
5090 image noise producing smooth images and making still images really
5091 still. It should enhance compressibility.
5093 It accepts the following optional parameters:
5097 a non-negative float number which specifies spatial luma strength,
5100 @item chroma_spatial
5101 a non-negative float number which specifies spatial chroma strength,
5102 defaults to 3.0*@var{luma_spatial}/4.0
5105 a float number which specifies luma temporal strength, defaults to
5106 6.0*@var{luma_spatial}/4.0
5109 a float number which specifies chroma temporal strength, defaults to
5110 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
5115 Modify the hue and/or the saturation of the input.
5117 This filter accepts the following options:
5121 Specify the hue angle as a number of degrees. It accepts an expression,
5122 and defaults to "0".
5125 Specify the saturation in the [-10,10] range. It accepts an expression and
5129 Specify the hue angle as a number of radians. It accepts an
5130 expression, and defaults to "0".
5133 Specify the brightness in the [-10,10] range. It accepts an expression and
5137 @option{h} and @option{H} are mutually exclusive, and can't be
5138 specified at the same time.
5140 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5141 expressions containing the following constants:
5145 frame count of the input frame starting from 0
5148 presentation timestamp of the input frame expressed in time base units
5151 frame rate of the input video, NAN if the input frame rate is unknown
5154 timestamp expressed in seconds, NAN if the input timestamp is unknown
5157 time base of the input video
5160 @subsection Examples
5164 Set the hue to 90 degrees and the saturation to 1.0:
5170 Same command but expressing the hue in radians:
5176 Rotate hue and make the saturation swing between 0
5177 and 2 over a period of 1 second:
5179 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5183 Apply a 3 seconds saturation fade-in effect starting at 0:
5188 The general fade-in expression can be written as:
5190 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5194 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5196 hue="s=max(0\, min(1\, (8-t)/3))"
5199 The general fade-out expression can be written as:
5201 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5206 @subsection Commands
5208 This filter supports the following commands:
5214 Modify the hue and/or the saturation and/or brightness of the input video.
5215 The command accepts the same syntax of the corresponding option.
5217 If the specified expression is not valid, it is kept at its current
5223 Detect video interlacing type.
5225 This filter tries to detect if the input is interlaced or progressive,
5226 top or bottom field first.
5228 The filter accepts the following options:
5232 Set interlacing threshold.
5234 Set progressive threshold.
5239 Deinterleave or interleave fields.
5241 This filter allows one to process interlaced images fields without
5242 deinterlacing them. Deinterleaving splits the input frame into 2
5243 fields (so called half pictures). Odd lines are moved to the top
5244 half of the output image, even lines to the bottom half.
5245 You can process (filter) them independently and then re-interleave them.
5247 The filter accepts the following options:
5251 @item chroma_mode, c
5253 Available values for @var{luma_mode}, @var{chroma_mode} and
5254 @var{alpha_mode} are:
5260 @item deinterleave, d
5261 Deinterleave fields, placing one above the other.
5264 Interleave fields. Reverse the effect of deinterleaving.
5266 Default value is @code{none}.
5269 @item chroma_swap, cs
5270 @item alpha_swap, as
5271 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5276 Simple interlacing filter from progressive contents. This interleaves upper (or
5277 lower) lines from odd frames with lower (or upper) lines from even frames,
5278 halving the frame rate and preserving image height. A vertical lowpass filter
5279 is always applied in order to avoid twitter effects and reduce moiré patterns.
5282 Original Original New Frame
5283 Frame 'j' Frame 'j+1' (tff)
5284 ========== =========== ==================
5285 Line 0 --------------------> Frame 'j' Line 0
5286 Line 1 Line 1 ----> Frame 'j+1' Line 1
5287 Line 2 ---------------------> Frame 'j' Line 2
5288 Line 3 Line 3 ----> Frame 'j+1' Line 3
5290 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5293 It accepts the following optional parameters:
5297 determines whether the interlaced frame is taken from the even (tff - default)
5298 or odd (bff) lines of the progressive frame.
5303 Deinterlace input video by applying Donald Graft's adaptive kernel
5304 deinterling. Work on interlaced parts of a video to produce
5307 The description of the accepted parameters follows.
5311 Set the threshold which affects the filter's tolerance when
5312 determining if a pixel line must be processed. It must be an integer
5313 in the range [0,255] and defaults to 10. A value of 0 will result in
5314 applying the process on every pixels.
5317 Paint pixels exceeding the threshold value to white if set to 1.
5321 Set the fields order. Swap fields if set to 1, leave fields alone if
5325 Enable additional sharpening if set to 1. Default is 0.
5328 Enable twoway sharpening if set to 1. Default is 0.
5331 @subsection Examples
5335 Apply default values:
5337 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5341 Enable additional sharpening:
5347 Paint processed pixels in white:
5356 Apply a 3D LUT to an input video.
5358 The filter accepts the following options:
5362 Set the 3D LUT file name.
5364 Currently supported formats:
5376 Select interpolation mode.
5378 Available values are:
5382 Use values from the nearest defined point.
5384 Interpolate values using the 8 points defining a cube.
5386 Interpolate values using a tetrahedron.
5390 @section lut, lutrgb, lutyuv
5392 Compute a look-up table for binding each pixel component input value
5393 to an output value, and apply it to input video.
5395 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5396 to an RGB input video.
5398 These filters accept the following options:
5401 set first pixel component expression
5403 set second pixel component expression
5405 set third pixel component expression
5407 set fourth pixel component expression, corresponds to the alpha component
5410 set red component expression
5412 set green component expression
5414 set blue component expression
5416 alpha component expression
5419 set Y/luminance component expression
5421 set U/Cb component expression
5423 set V/Cr component expression
5426 Each of them specifies the expression to use for computing the lookup table for
5427 the corresponding pixel component values.
5429 The exact component associated to each of the @var{c*} options depends on the
5432 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5433 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5435 The expressions can contain the following constants and functions:
5440 the input width and height
5443 input value for the pixel component
5446 the input value clipped in the @var{minval}-@var{maxval} range
5449 maximum value for the pixel component
5452 minimum value for the pixel component
5455 the negated value for the pixel component value clipped in the
5456 @var{minval}-@var{maxval} range , it corresponds to the expression
5457 "maxval-clipval+minval"
5460 the computed value in @var{val} clipped in the
5461 @var{minval}-@var{maxval} range
5463 @item gammaval(gamma)
5464 the computed gamma correction value of the pixel component value
5465 clipped in the @var{minval}-@var{maxval} range, corresponds to the
5467 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
5471 All expressions default to "val".
5473 @subsection Examples
5479 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
5480 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
5483 The above is the same as:
5485 lutrgb="r=negval:g=negval:b=negval"
5486 lutyuv="y=negval:u=negval:v=negval"
5496 Remove chroma components, turns the video into a graytone image:
5498 lutyuv="u=128:v=128"
5502 Apply a luma burning effect:
5508 Remove green and blue components:
5514 Set a constant alpha channel value on input:
5516 format=rgba,lutrgb=a="maxval-minval/2"
5520 Correct luminance gamma by a 0.5 factor:
5522 lutyuv=y=gammaval(0.5)
5526 Discard least significant bits of luma:
5528 lutyuv=y='bitand(val, 128+64+32)'
5532 @section mergeplanes
5534 Merge color channel components from several video streams.
5536 The filter accepts up to 4 input streams, and merge selected input
5537 planes to the output video.
5539 This filter accepts the following options:
5542 Set input to output plane mapping. Default is @code{0}.
5544 The mappings is specified as a bitmap. It should be specified as a
5545 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
5546 mapping for the first plane of the output stream. 'A' sets the number of
5547 the input stream to use (from 0 to 3), and 'a' the plane number of the
5548 corresponding input to use (from 0 to 3). The rest of the mappings is
5549 similar, 'Bb' describes the mapping for the output stream second
5550 plane, 'Cc' describes the mapping for the output stream third plane and
5551 'Dd' describes the mapping for the output stream fourth plane.
5554 Set output pixel format. Default is @code{yuva444p}.
5557 @subsection Examples
5561 Merge three gray video streams of same width and height into single video stream:
5563 [a0][a1][a2]mergeplanes=0x001020:yuv444p
5567 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
5569 [a0][a1]mergeplanes=0x00010210:yuva444p
5573 Swap Y and A plane in yuva444p stream:
5575 format=yuva444p,mergeplanes=0x03010200:yuva444p
5579 Swap U and V plane in yuv420p stream:
5581 format=yuv420p,mergeplanes=0x000201:yuv420p
5585 Cast a rgb24 clip to yuv444p:
5587 format=rgb24,mergeplanes=0x000102:yuv444p
5593 Apply motion-compensation deinterlacing.
5595 It needs one field per frame as input and must thus be used together
5596 with yadif=1/3 or equivalent.
5598 This filter accepts the following options:
5601 Set the deinterlacing mode.
5603 It accepts one of the following values:
5608 use iterative motion estimation
5610 like @samp{slow}, but use multiple reference frames.
5612 Default value is @samp{fast}.
5615 Set the picture field parity assumed for the input video. It must be
5616 one of the following values:
5620 assume top field first
5622 assume bottom field first
5625 Default value is @samp{bff}.
5628 Set per-block quantization parameter (QP) used by the internal
5631 Higher values should result in a smoother motion vector field but less
5632 optimal individual vectors. Default value is 1.
5637 Apply an MPlayer filter to the input video.
5639 This filter provides a wrapper around some of the filters of
5642 This wrapper is considered experimental. Some of the wrapped filters
5643 may not work properly and we may drop support for them, as they will
5644 be implemented natively into FFmpeg. Thus you should avoid
5645 depending on them when writing portable scripts.
5647 The filter accepts the parameters:
5648 @var{filter_name}[:=]@var{filter_params}
5650 @var{filter_name} is the name of a supported MPlayer filter,
5651 @var{filter_params} is a string containing the parameters accepted by
5654 The list of the currently supported filters follows:
5665 The parameter syntax and behavior for the listed filters are the same
5666 of the corresponding MPlayer filters. For detailed instructions check
5667 the "VIDEO FILTERS" section in the MPlayer manual.
5669 @subsection Examples
5673 Adjust gamma, brightness, contrast:
5679 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
5683 Drop frames that do not differ greatly from the previous frame in
5684 order to reduce frame rate.
5686 The main use of this filter is for very-low-bitrate encoding
5687 (e.g. streaming over dialup modem), but it could in theory be used for
5688 fixing movies that were inverse-telecined incorrectly.
5690 A description of the accepted options follows.
5694 Set the maximum number of consecutive frames which can be dropped (if
5695 positive), or the minimum interval between dropped frames (if
5696 negative). If the value is 0, the frame is dropped unregarding the
5697 number of previous sequentially dropped frames.
5704 Set the dropping threshold values.
5706 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
5707 represent actual pixel value differences, so a threshold of 64
5708 corresponds to 1 unit of difference for each pixel, or the same spread
5709 out differently over the block.
5711 A frame is a candidate for dropping if no 8x8 blocks differ by more
5712 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
5713 meaning the whole image) differ by more than a threshold of @option{lo}.
5715 Default value for @option{hi} is 64*12, default value for @option{lo} is
5716 64*5, and default value for @option{frac} is 0.33.
5724 This filter accepts an integer in input, if non-zero it negates the
5725 alpha component (if available). The default value in input is 0.
5729 Force libavfilter not to use any of the specified pixel formats for the
5730 input to the next filter.
5732 This filter accepts the following parameters:
5736 A '|'-separated list of pixel format names, for example
5737 "pix_fmts=yuv420p|monow|rgb24".
5741 @subsection Examples
5745 Force libavfilter to use a format different from @var{yuv420p} for the
5746 input to the vflip filter:
5748 noformat=pix_fmts=yuv420p,vflip
5752 Convert the input video to any of the formats not contained in the list:
5754 noformat=yuv420p|yuv444p|yuv410p
5760 Add noise on video input frame.
5762 The filter accepts the following options:
5770 Set noise seed for specific pixel component or all pixel components in case
5771 of @var{all_seed}. Default value is @code{123457}.
5773 @item all_strength, alls
5774 @item c0_strength, c0s
5775 @item c1_strength, c1s
5776 @item c2_strength, c2s
5777 @item c3_strength, c3s
5778 Set noise strength for specific pixel component or all pixel components in case
5779 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
5781 @item all_flags, allf
5786 Set pixel component flags or set flags for all components if @var{all_flags}.
5787 Available values for component flags are:
5790 averaged temporal noise (smoother)
5792 mix random noise with a (semi)regular pattern
5794 temporal noise (noise pattern changes between frames)
5796 uniform noise (gaussian otherwise)
5800 @subsection Examples
5802 Add temporal and uniform noise to input video:
5804 noise=alls=20:allf=t+u
5809 Pass the video source unchanged to the output.
5813 Apply video transform using libopencv.
5815 To enable this filter install libopencv library and headers and
5816 configure FFmpeg with @code{--enable-libopencv}.
5818 This filter accepts the following parameters:
5823 The name of the libopencv filter to apply.
5826 The parameters to pass to the libopencv filter. If not specified the default
5831 Refer to the official libopencv documentation for more precise
5833 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
5835 Follows the list of supported libopencv filters.
5840 Dilate an image by using a specific structuring element.
5841 This filter corresponds to the libopencv function @code{cvDilate}.
5843 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
5845 @var{struct_el} represents a structuring element, and has the syntax:
5846 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
5848 @var{cols} and @var{rows} represent the number of columns and rows of
5849 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
5850 point, and @var{shape} the shape for the structuring element, and
5851 can be one of the values "rect", "cross", "ellipse", "custom".
5853 If the value for @var{shape} is "custom", it must be followed by a
5854 string of the form "=@var{filename}". The file with name
5855 @var{filename} is assumed to represent a binary image, with each
5856 printable character corresponding to a bright pixel. When a custom
5857 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
5858 or columns and rows of the read file are assumed instead.
5860 The default value for @var{struct_el} is "3x3+0x0/rect".
5862 @var{nb_iterations} specifies the number of times the transform is
5863 applied to the image, and defaults to 1.
5865 Follow some example:
5867 # use the default values
5870 # dilate using a structuring element with a 5x5 cross, iterate two times
5871 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
5873 # read the shape from the file diamond.shape, iterate two times
5874 # the file diamond.shape may contain a pattern of characters like this:
5880 # the specified cols and rows are ignored (but not the anchor point coordinates)
5881 ocv=dilate:0x0+2x2/custom=diamond.shape|2
5886 Erode an image by using a specific structuring element.
5887 This filter corresponds to the libopencv function @code{cvErode}.
5889 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
5890 with the same syntax and semantics as the @ref{dilate} filter.
5894 Smooth the input video.
5896 The filter takes the following parameters:
5897 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
5899 @var{type} is the type of smooth filter to apply, and can be one of
5900 the following values: "blur", "blur_no_scale", "median", "gaussian",
5901 "bilateral". The default value is "gaussian".
5903 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
5904 parameters whose meanings depend on smooth type. @var{param1} and
5905 @var{param2} accept integer positive values or 0, @var{param3} and
5906 @var{param4} accept float values.
5908 The default value for @var{param1} is 3, the default value for the
5909 other parameters is 0.
5911 These parameters correspond to the parameters assigned to the
5912 libopencv function @code{cvSmooth}.
5917 Overlay one video on top of another.
5919 It takes two inputs and one output, the first input is the "main"
5920 video on which the second input is overlayed.
5922 This filter accepts the following parameters:
5924 A description of the accepted options follows.
5929 Set the expression for the x and y coordinates of the overlayed video
5930 on the main video. Default value is "0" for both expressions. In case
5931 the expression is invalid, it is set to a huge value (meaning that the
5932 overlay will not be displayed within the output visible area).
5935 The action to take when EOF is encountered on the secondary input, accepts one
5936 of the following values:
5940 repeat the last frame (the default)
5944 pass through the main input
5948 Set when the expressions for @option{x}, and @option{y} are evaluated.
5950 It accepts the following values:
5953 only evaluate expressions once during the filter initialization or
5954 when a command is processed
5957 evaluate expressions for each incoming frame
5960 Default value is @samp{frame}.
5963 If set to 1, force the output to terminate when the shortest input
5964 terminates. Default value is 0.
5967 Set the format for the output video.
5969 It accepts the following values:
5984 Default value is @samp{yuv420}.
5986 @item rgb @emph{(deprecated)}
5987 If set to 1, force the filter to accept inputs in the RGB
5988 color space. Default value is 0. This option is deprecated, use
5989 @option{format} instead.
5992 If set to 1, force the filter to draw the last overlay frame over the
5993 main input until the end of the stream. A value of 0 disables this
5994 behavior. Default value is 1.
5997 The @option{x}, and @option{y} expressions can contain the following
6003 main input width and height
6007 overlay input width and height
6011 the computed values for @var{x} and @var{y}. They are evaluated for
6016 horizontal and vertical chroma subsample values of the output
6017 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6021 the number of input frame, starting from 0
6024 the position in the file of the input frame, NAN if unknown
6027 timestamp expressed in seconds, NAN if the input timestamp is unknown
6031 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6032 when evaluation is done @emph{per frame}, and will evaluate to NAN
6033 when @option{eval} is set to @samp{init}.
6035 Be aware that frames are taken from each input video in timestamp
6036 order, hence, if their initial timestamps differ, it is a good idea
6037 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6038 have them begin in the same zero timestamp, as it does the example for
6039 the @var{movie} filter.
6041 You can chain together more overlays but you should test the
6042 efficiency of such approach.
6044 @subsection Commands
6046 This filter supports the following commands:
6050 Modify the x and y of the overlay input.
6051 The command accepts the same syntax of the corresponding option.
6053 If the specified expression is not valid, it is kept at its current
6057 @subsection Examples
6061 Draw the overlay at 10 pixels from the bottom right corner of the main
6064 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6067 Using named options the example above becomes:
6069 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6073 Insert a transparent PNG logo in the bottom left corner of the input,
6074 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6076 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6080 Insert 2 different transparent PNG logos (second logo on bottom
6081 right corner) using the @command{ffmpeg} tool:
6083 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
6087 Add a transparent color layer on top of the main video, @code{WxH}
6088 must specify the size of the main input to the overlay filter:
6090 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6094 Play an original video and a filtered version (here with the deshake
6095 filter) side by side using the @command{ffplay} tool:
6097 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6100 The above command is the same as:
6102 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6106 Make a sliding overlay appearing from the left to the right top part of the
6107 screen starting since time 2:
6109 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6113 Compose output by putting two input videos side to side:
6115 ffmpeg -i left.avi -i right.avi -filter_complex "
6116 nullsrc=size=200x100 [background];
6117 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6118 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6119 [background][left] overlay=shortest=1 [background+left];
6120 [background+left][right] overlay=shortest=1:x=100 [left+right]
6125 mask 10-20 seconds of a video by applying the delogo filter to a section
6127 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6128 -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]'
6133 Chain several overlays in cascade:
6135 nullsrc=s=200x200 [bg];
6136 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6137 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6138 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6139 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6140 [in3] null, [mid2] overlay=100:100 [out0]
6147 Apply Overcomplete Wavelet denoiser.
6149 The filter accepts the following options:
6155 Larger depth values will denoise lower frequency components more, but
6156 slow down filtering.
6158 Must be an int in the range 8-16, default is @code{8}.
6160 @item luma_strength, ls
6163 Must be a double value in the range 0-1000, default is @code{1.0}.
6165 @item chroma_strength, cs
6166 Set chroma strength.
6168 Must be a double value in the range 0-1000, default is @code{1.0}.
6173 Add paddings to the input image, and place the original input at the
6174 given coordinates @var{x}, @var{y}.
6176 This filter accepts the following parameters:
6181 Specify an expression for the size of the output image with the
6182 paddings added. If the value for @var{width} or @var{height} is 0, the
6183 corresponding input size is used for the output.
6185 The @var{width} expression can reference the value set by the
6186 @var{height} expression, and vice versa.
6188 The default value of @var{width} and @var{height} is 0.
6192 Specify an expression for the offsets where to place the input image
6193 in the padded area with respect to the top/left border of the output
6196 The @var{x} expression can reference the value set by the @var{y}
6197 expression, and vice versa.
6199 The default value of @var{x} and @var{y} is 0.
6202 Specify the color of the padded area. For the syntax of this option,
6203 check the "Color" section in the ffmpeg-utils manual.
6205 The default value of @var{color} is "black".
6208 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6209 options are expressions containing the following constants:
6214 the input video width and height
6218 same as @var{in_w} and @var{in_h}
6222 the output width and height, that is the size of the padded area as
6223 specified by the @var{width} and @var{height} expressions
6227 same as @var{out_w} and @var{out_h}
6231 x and y offsets as specified by the @var{x} and @var{y}
6232 expressions, or NAN if not yet specified
6235 same as @var{iw} / @var{ih}
6238 input sample aspect ratio
6241 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6245 horizontal and vertical chroma subsample values. For example for the
6246 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6249 @subsection Examples
6253 Add paddings with color "violet" to the input video. Output video
6254 size is 640x480, the top-left corner of the input video is placed at
6257 pad=640:480:0:40:violet
6260 The example above is equivalent to the following command:
6262 pad=width=640:height=480:x=0:y=40:color=violet
6266 Pad the input to get an output with dimensions increased by 3/2,
6267 and put the input video at the center of the padded area:
6269 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6273 Pad the input to get a squared output with size equal to the maximum
6274 value between the input width and height, and put the input video at
6275 the center of the padded area:
6277 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6281 Pad the input to get a final w/h ratio of 16:9:
6283 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6287 In case of anamorphic video, in order to set the output display aspect
6288 correctly, it is necessary to use @var{sar} in the expression,
6289 according to the relation:
6291 (ih * X / ih) * sar = output_dar
6292 X = output_dar / sar
6295 Thus the previous example needs to be modified to:
6297 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6301 Double output size and put the input video in the bottom-right
6302 corner of the output padded area:
6304 pad="2*iw:2*ih:ow-iw:oh-ih"
6308 @section perspective
6310 Correct perspective of video not recorded perpendicular to the screen.
6312 A description of the accepted parameters follows.
6323 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6324 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6326 The expressions can use the following variables:
6331 the width and height of video frame.
6335 Set interpolation for perspective correction.
6337 It accepts the following values:
6343 Default value is @samp{linear}.
6348 Delay interlaced video by one field time so that the field order changes.
6350 The intended use is to fix PAL movies that have been captured with the
6351 opposite field order to the film-to-video transfer.
6353 A description of the accepted parameters follows.
6359 It accepts the following values:
6362 Capture field order top-first, transfer bottom-first.
6363 Filter will delay the bottom field.
6366 Capture field order bottom-first, transfer top-first.
6367 Filter will delay the top field.
6370 Capture and transfer with the same field order. This mode only exists
6371 for the documentation of the other options to refer to, but if you
6372 actually select it, the filter will faithfully do nothing.
6375 Capture field order determined automatically by field flags, transfer
6377 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6378 basis using field flags. If no field information is available,
6379 then this works just like @samp{u}.
6382 Capture unknown or varying, transfer opposite.
6383 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6384 analyzing the images and selecting the alternative that produces best
6385 match between the fields.
6388 Capture top-first, transfer unknown or varying.
6389 Filter selects among @samp{t} and @samp{p} using image analysis.
6392 Capture bottom-first, transfer unknown or varying.
6393 Filter selects among @samp{b} and @samp{p} using image analysis.
6396 Capture determined by field flags, transfer unknown or varying.
6397 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6398 image analysis. If no field information is available, then this works just
6399 like @samp{U}. This is the default mode.
6402 Both capture and transfer unknown or varying.
6403 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
6407 @section pixdesctest
6409 Pixel format descriptor test filter, mainly useful for internal
6410 testing. The output video should be equal to the input video.
6414 format=monow, pixdesctest
6417 can be used to test the monowhite pixel format descriptor definition.
6421 Enable the specified chain of postprocessing subfilters using libpostproc. This
6422 library should be automatically selected with a GPL build (@code{--enable-gpl}).
6423 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
6424 Each subfilter and some options have a short and a long name that can be used
6425 interchangeably, i.e. dr/dering are the same.
6427 The filters accept the following options:
6431 Set postprocessing subfilters string.
6434 All subfilters share common options to determine their scope:
6438 Honor the quality commands for this subfilter.
6441 Do chrominance filtering, too (default).
6444 Do luminance filtering only (no chrominance).
6447 Do chrominance filtering only (no luminance).
6450 These options can be appended after the subfilter name, separated by a '|'.
6452 Available subfilters are:
6455 @item hb/hdeblock[|difference[|flatness]]
6456 Horizontal deblocking filter
6459 Difference factor where higher values mean more deblocking (default: @code{32}).
6461 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6464 @item vb/vdeblock[|difference[|flatness]]
6465 Vertical deblocking filter
6468 Difference factor where higher values mean more deblocking (default: @code{32}).
6470 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6473 @item ha/hadeblock[|difference[|flatness]]
6474 Accurate horizontal deblocking filter
6477 Difference factor where higher values mean more deblocking (default: @code{32}).
6479 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6482 @item va/vadeblock[|difference[|flatness]]
6483 Accurate vertical deblocking filter
6486 Difference factor where higher values mean more deblocking (default: @code{32}).
6488 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6492 The horizontal and vertical deblocking filters share the difference and
6493 flatness values so you cannot set different horizontal and vertical
6498 Experimental horizontal deblocking filter
6501 Experimental vertical deblocking filter
6506 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
6509 larger -> stronger filtering
6511 larger -> stronger filtering
6513 larger -> stronger filtering
6516 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
6519 Stretch luminance to @code{0-255}.
6522 @item lb/linblenddeint
6523 Linear blend deinterlacing filter that deinterlaces the given block by
6524 filtering all lines with a @code{(1 2 1)} filter.
6526 @item li/linipoldeint
6527 Linear interpolating deinterlacing filter that deinterlaces the given block by
6528 linearly interpolating every second line.
6530 @item ci/cubicipoldeint
6531 Cubic interpolating deinterlacing filter deinterlaces the given block by
6532 cubically interpolating every second line.
6534 @item md/mediandeint
6535 Median deinterlacing filter that deinterlaces the given block by applying a
6536 median filter to every second line.
6538 @item fd/ffmpegdeint
6539 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
6540 second line with a @code{(-1 4 2 4 -1)} filter.
6543 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
6544 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
6546 @item fq/forceQuant[|quantizer]
6547 Overrides the quantizer table from the input with the constant quantizer you
6555 Default pp filter combination (@code{hb|a,vb|a,dr|a})
6558 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
6561 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
6564 @subsection Examples
6568 Apply horizontal and vertical deblocking, deringing and automatic
6569 brightness/contrast:
6575 Apply default filters without brightness/contrast correction:
6581 Apply default filters and temporal denoiser:
6583 pp=default/tmpnoise|1|2|3
6587 Apply deblocking on luminance only, and switch vertical deblocking on or off
6588 automatically depending on available CPU time:
6596 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
6597 Ratio) between two input videos.
6599 This filter takes in input two input videos, the first input is
6600 considered the "main" source and is passed unchanged to the
6601 output. The second input is used as a "reference" video for computing
6604 Both video inputs must have the same resolution and pixel format for
6605 this filter to work correctly. Also it assumes that both inputs
6606 have the same number of frames, which are compared one by one.
6608 The obtained average PSNR is printed through the logging system.
6610 The filter stores the accumulated MSE (mean squared error) of each
6611 frame, and at the end of the processing it is averaged across all frames
6612 equally, and the following formula is applied to obtain the PSNR:
6615 PSNR = 10*log10(MAX^2/MSE)
6618 Where MAX is the average of the maximum values of each component of the
6621 The description of the accepted parameters follows.
6625 If specified the filter will use the named file to save the PSNR of
6626 each individual frame.
6629 The file printed if @var{stats_file} is selected, contains a sequence of
6630 key/value pairs of the form @var{key}:@var{value} for each compared
6633 A description of each shown parameter follows:
6637 sequential number of the input frame, starting from 1
6640 Mean Square Error pixel-by-pixel average difference of the compared
6641 frames, averaged over all the image components.
6643 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
6644 Mean Square Error pixel-by-pixel average difference of the compared
6645 frames for the component specified by the suffix.
6647 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
6648 Peak Signal to Noise ratio of the compared frames for the component
6649 specified by the suffix.
6654 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
6655 [main][ref] psnr="stats_file=stats.log" [out]
6658 On this example the input file being processed is compared with the
6659 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
6660 is stored in @file{stats.log}.
6665 Pulldown reversal (inverse telecine) filter, capable of handling mixed
6666 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
6669 The pullup filter is designed to take advantage of future context in making
6670 its decisions. This filter is stateless in the sense that it does not lock
6671 onto a pattern to follow, but it instead looks forward to the following
6672 fields in order to identify matches and rebuild progressive frames.
6674 To produce content with an even framerate, insert the fps filter after
6675 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
6676 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
6678 The filter accepts the following options:
6685 These options set the amount of "junk" to ignore at the left, right, top, and
6686 bottom of the image, respectively. Left and right are in units of 8 pixels,
6687 while top and bottom are in units of 2 lines.
6688 The default is 8 pixels on each side.
6691 Set the strict breaks. Setting this option to 1 will reduce the chances of
6692 filter generating an occasional mismatched frame, but it may also cause an
6693 excessive number of frames to be dropped during high motion sequences.
6694 Conversely, setting it to -1 will make filter match fields more easily.
6695 This may help processing of video where there is slight blurring between
6696 the fields, but may also cause there to be interlaced frames in the output.
6697 Default value is @code{0}.
6700 Set the metric plane to use. It accepts the following values:
6706 Use chroma blue plane.
6709 Use chroma red plane.
6712 This option may be set to use chroma plane instead of the default luma plane
6713 for doing filter's computations. This may improve accuracy on very clean
6714 source material, but more likely will decrease accuracy, especially if there
6715 is chroma noise (rainbow effect) or any grayscale video.
6716 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
6717 load and make pullup usable in realtime on slow machines.
6720 For best results (without duplicated frames in the output file) it is
6721 necessary to change the output frame rate. For example, to inverse
6722 telecine NTSC input:
6724 ffmpeg -i input -vf pullup -r 24000/1001 ...
6729 Suppress a TV station logo, using an image file to determine which
6730 pixels comprise the logo. It works by filling in the pixels that
6731 comprise the logo with neighboring pixels.
6733 The filter accepts the following options:
6737 Set the filter bitmap file, which can be any image format supported by
6738 libavformat. The width and height of the image file must match those of the
6739 video stream being processed.
6742 Pixels in the provided bitmap image with a value of zero are not
6743 considered part of the logo, non-zero pixels are considered part of
6744 the logo. If you use white (255) for the logo and black (0) for the
6745 rest, you will be safe. For making the filter bitmap, it is
6746 recommended to take a screen capture of a black frame with the logo
6747 visible, and then using a threshold filter followed by the erode
6748 filter once or twice.
6750 If needed, little splotches can be fixed manually. Remember that if
6751 logo pixels are not covered, the filter quality will be much
6752 reduced. Marking too many pixels as part of the logo does not hurt as
6753 much, but it will increase the amount of blurring needed to cover over
6754 the image and will destroy more information than necessary, and extra
6755 pixels will slow things down on a large logo.
6759 Rotate video by an arbitrary angle expressed in radians.
6761 The filter accepts the following options:
6763 A description of the optional parameters follows.
6766 Set an expression for the angle by which to rotate the input video
6767 clockwise, expressed as a number of radians. A negative value will
6768 result in a counter-clockwise rotation. By default it is set to "0".
6770 This expression is evaluated for each frame.
6773 Set the output width expression, default value is "iw".
6774 This expression is evaluated just once during configuration.
6777 Set the output height expression, default value is "ih".
6778 This expression is evaluated just once during configuration.
6781 Enable bilinear interpolation if set to 1, a value of 0 disables
6782 it. Default value is 1.
6785 Set the color used to fill the output area not covered by the rotated
6786 image. For the generalsyntax of this option, check the "Color" section in the
6787 ffmpeg-utils manual. If the special value "none" is selected then no
6788 background is printed (useful for example if the background is never shown).
6790 Default value is "black".
6793 The expressions for the angle and the output size can contain the
6794 following constants and functions:
6798 sequential number of the input frame, starting from 0. It is always NAN
6799 before the first frame is filtered.
6802 time in seconds of the input frame, it is set to 0 when the filter is
6803 configured. It is always NAN before the first frame is filtered.
6807 horizontal and vertical chroma subsample values. For example for the
6808 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6812 the input video width and height
6816 the output width and height, that is the size of the padded area as
6817 specified by the @var{width} and @var{height} expressions
6821 the minimal width/height required for completely containing the input
6822 video rotated by @var{a} radians.
6824 These are only available when computing the @option{out_w} and
6825 @option{out_h} expressions.
6828 @subsection Examples
6832 Rotate the input by PI/6 radians clockwise:
6838 Rotate the input by PI/6 radians counter-clockwise:
6844 Rotate the input by 45 degrees clockwise:
6850 Apply a constant rotation with period T, starting from an angle of PI/3:
6852 rotate=PI/3+2*PI*t/T
6856 Make the input video rotation oscillating with a period of T
6857 seconds and an amplitude of A radians:
6859 rotate=A*sin(2*PI/T*t)
6863 Rotate the video, output size is chosen so that the whole rotating
6864 input video is always completely contained in the output:
6866 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
6870 Rotate the video, reduce the output size so that no background is ever
6873 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
6877 @subsection Commands
6879 The filter supports the following commands:
6883 Set the angle expression.
6884 The command accepts the same syntax of the corresponding option.
6886 If the specified expression is not valid, it is kept at its current
6892 Apply Shape Adaptive Blur.
6894 The filter accepts the following options:
6897 @item luma_radius, lr
6898 Set luma blur filter strength, must be a value in range 0.1-4.0, default
6899 value is 1.0. A greater value will result in a more blurred image, and
6900 in slower processing.
6902 @item luma_pre_filter_radius, lpfr
6903 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
6906 @item luma_strength, ls
6907 Set luma maximum difference between pixels to still be considered, must
6908 be a value in the 0.1-100.0 range, default value is 1.0.
6910 @item chroma_radius, cr
6911 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
6912 greater value will result in a more blurred image, and in slower
6915 @item chroma_pre_filter_radius, cpfr
6916 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
6918 @item chroma_strength, cs
6919 Set chroma maximum difference between pixels to still be considered,
6920 must be a value in the 0.1-100.0 range.
6923 Each chroma option value, if not explicitly specified, is set to the
6924 corresponding luma option value.
6929 Scale (resize) the input video, using the libswscale library.
6931 The scale filter forces the output display aspect ratio to be the same
6932 of the input, by changing the output sample aspect ratio.
6934 If the input image format is different from the format requested by
6935 the next filter, the scale filter will convert the input to the
6939 The filter accepts the following options, or any of the options
6940 supported by the libswscale scaler.
6942 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
6943 the complete list of scaler options.
6948 Set the output video dimension expression. Default value is the input
6951 If the value is 0, the input width is used for the output.
6953 If one of the values is -1, the scale filter will use a value that
6954 maintains the aspect ratio of the input image, calculated from the
6955 other specified dimension. If both of them are -1, the input size is
6958 If one of the values is -n with n > 1, the scale filter will also use a value
6959 that maintains the aspect ratio of the input image, calculated from the other
6960 specified dimension. After that it will, however, make sure that the calculated
6961 dimension is divisible by n and adjust the value if necessary.
6963 See below for the list of accepted constants for use in the dimension
6967 Set the interlacing mode. It accepts the following values:
6971 Force interlaced aware scaling.
6974 Do not apply interlaced scaling.
6977 Select interlaced aware scaling depending on whether the source frames
6978 are flagged as interlaced or not.
6981 Default value is @samp{0}.
6984 Set libswscale scaling flags. See
6985 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
6986 complete list of values. If not explicitly specified the filter applies
6990 Set the video size. For the syntax of this option, check the "Video size"
6991 section in the ffmpeg-utils manual.
6993 @item in_color_matrix
6994 @item out_color_matrix
6995 Set in/output YCbCr color space type.
6997 This allows the autodetected value to be overridden as well as allows forcing
6998 a specific value used for the output and encoder.
7000 If not specified, the color space type depends on the pixel format.
7006 Choose automatically.
7009 Format conforming to International Telecommunication Union (ITU)
7010 Recommendation BT.709.
7013 Set color space conforming to the United States Federal Communications
7014 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7017 Set color space conforming to:
7021 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7024 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7027 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7032 Set color space conforming to SMPTE ST 240:1999.
7037 Set in/output YCbCr sample range.
7039 This allows the autodetected value to be overridden as well as allows forcing
7040 a specific value used for the output and encoder. If not specified, the
7041 range depends on the pixel format. Possible values:
7045 Choose automatically.
7048 Set full range (0-255 in case of 8-bit luma).
7051 Set "MPEG" range (16-235 in case of 8-bit luma).
7054 @item force_original_aspect_ratio
7055 Enable decreasing or increasing output video width or height if necessary to
7056 keep the original aspect ratio. Possible values:
7060 Scale the video as specified and disable this feature.
7063 The output video dimensions will automatically be decreased if needed.
7066 The output video dimensions will automatically be increased if needed.
7070 One useful instance of this option is that when you know a specific device's
7071 maximum allowed resolution, you can use this to limit the output video to
7072 that, while retaining the aspect ratio. For example, device A allows
7073 1280x720 playback, and your video is 1920x800. Using this option (set it to
7074 decrease) and specifying 1280x720 to the command line makes the output
7077 Please note that this is a different thing than specifying -1 for @option{w}
7078 or @option{h}, you still need to specify the output resolution for this option
7083 The values of the @option{w} and @option{h} options are expressions
7084 containing the following constants:
7089 the input width and height
7093 same as @var{in_w} and @var{in_h}
7097 the output (scaled) width and height
7101 same as @var{out_w} and @var{out_h}
7104 same as @var{iw} / @var{ih}
7107 input sample aspect ratio
7110 input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7114 horizontal and vertical input chroma subsample values. For example for the
7115 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7119 horizontal and vertical output chroma subsample values. For example for the
7120 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7123 @subsection Examples
7127 Scale the input video to a size of 200x100:
7132 This is equivalent to:
7143 Specify a size abbreviation for the output size:
7148 which can also be written as:
7154 Scale the input to 2x:
7160 The above is the same as:
7166 Scale the input to 2x with forced interlaced scaling:
7168 scale=2*iw:2*ih:interl=1
7172 Scale the input to half size:
7178 Increase the width, and set the height to the same size:
7184 Seek for Greek harmony:
7191 Increase the height, and set the width to 3/2 of the height:
7193 scale=w=3/2*oh:h=3/5*ih
7197 Increase the size, but make the size a multiple of the chroma
7200 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7204 Increase the width to a maximum of 500 pixels, keep the same input
7207 scale=w='min(500\, iw*3/2):h=-1'
7211 @section separatefields
7213 The @code{separatefields} takes a frame-based video input and splits
7214 each frame into its components fields, producing a new half height clip
7215 with twice the frame rate and twice the frame count.
7217 This filter use field-dominance information in frame to decide which
7218 of each pair of fields to place first in the output.
7219 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7221 @section setdar, setsar
7223 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7226 This is done by changing the specified Sample (aka Pixel) Aspect
7227 Ratio, according to the following equation:
7229 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7232 Keep in mind that the @code{setdar} filter does not modify the pixel
7233 dimensions of the video frame. Also the display aspect ratio set by
7234 this filter may be changed by later filters in the filterchain,
7235 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7238 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7239 the filter output video.
7241 Note that as a consequence of the application of this filter, the
7242 output display aspect ratio will change according to the equation
7245 Keep in mind that the sample aspect ratio set by the @code{setsar}
7246 filter may be changed by later filters in the filterchain, e.g. if
7247 another "setsar" or a "setdar" filter is applied.
7249 The filters accept the following options:
7252 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7253 Set the aspect ratio used by the filter.
7255 The parameter can be a floating point number string, an expression, or
7256 a string of the form @var{num}:@var{den}, where @var{num} and
7257 @var{den} are the numerator and denominator of the aspect ratio. If
7258 the parameter is not specified, it is assumed the value "0".
7259 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7263 Set the maximum integer value to use for expressing numerator and
7264 denominator when reducing the expressed aspect ratio to a rational.
7265 Default value is @code{100}.
7269 The parameter @var{sar} is an expression containing
7270 the following constants:
7274 the corresponding mathematical approximated values for e
7275 (euler number), pi (greek PI), phi (golden ratio)
7278 the input width and height
7281 same as @var{w} / @var{h}
7284 input sample aspect ratio
7287 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
7290 horizontal and vertical chroma subsample values. For example for the
7291 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7294 @subsection Examples
7299 To change the display aspect ratio to 16:9, specify one of the following:
7307 To change the sample aspect ratio to 10:11, specify:
7313 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7314 1000 in the aspect ratio reduction, use the command:
7316 setdar=ratio=16/9:max=1000
7324 Force field for the output video frame.
7326 The @code{setfield} filter marks the interlace type field for the
7327 output frames. It does not change the input frame, but only sets the
7328 corresponding property, which affects how the frame is treated by
7329 following filters (e.g. @code{fieldorder} or @code{yadif}).
7331 The filter accepts the following options:
7336 Available values are:
7340 Keep the same field property.
7343 Mark the frame as bottom-field-first.
7346 Mark the frame as top-field-first.
7349 Mark the frame as progressive.
7355 Show a line containing various information for each input video frame.
7356 The input video is not modified.
7358 The shown line contains a sequence of key/value pairs of the form
7359 @var{key}:@var{value}.
7361 A description of each shown parameter follows:
7365 sequential number of the input frame, starting from 0
7368 Presentation TimeStamp of the input frame, expressed as a number of
7369 time base units. The time base unit depends on the filter input pad.
7372 Presentation TimeStamp of the input frame, expressed as a number of
7376 position of the frame in the input stream, -1 if this information in
7377 unavailable and/or meaningless (for example in case of synthetic video)
7383 sample aspect ratio of the input frame, expressed in the form
7387 size of the input frame. For the syntax of this option, check the "Video size"
7388 section in the ffmpeg-utils manual.
7391 interlaced mode ("P" for "progressive", "T" for top field first, "B"
7392 for bottom field first)
7395 1 if the frame is a key frame, 0 otherwise
7398 picture type of the input frame ("I" for an I-frame, "P" for a
7399 P-frame, "B" for a B-frame, "?" for unknown type).
7400 Check also the documentation of the @code{AVPictureType} enum and of
7401 the @code{av_get_picture_type_char} function defined in
7402 @file{libavutil/avutil.h}.
7405 Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame
7407 @item plane_checksum
7408 Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
7409 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]"
7412 @section shuffleplanes
7414 Reorder and/or duplicate video planes.
7416 This filter accepts the following options:
7421 The index of the input plane to be used as the first output plane.
7424 The index of the input plane to be used as the second output plane.
7427 The index of the input plane to be used as the third output plane.
7430 The index of the input plane to be used as the fourth output plane.
7434 The first plane has the index 0. The default is to keep the input unchanged.
7438 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
7440 swaps the second and third planes of the input.
7445 Blur the input video without impacting the outlines.
7447 The filter accepts the following options:
7450 @item luma_radius, lr
7451 Set the luma radius. The option value must be a float number in
7452 the range [0.1,5.0] that specifies the variance of the gaussian filter
7453 used to blur the image (slower if larger). Default value is 1.0.
7455 @item luma_strength, ls
7456 Set the luma strength. The option value must be a float number
7457 in the range [-1.0,1.0] that configures the blurring. A value included
7458 in [0.0,1.0] will blur the image whereas a value included in
7459 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7461 @item luma_threshold, lt
7462 Set the luma threshold used as a coefficient to determine
7463 whether a pixel should be blurred or not. The option value must be an
7464 integer in the range [-30,30]. A value of 0 will filter all the image,
7465 a value included in [0,30] will filter flat areas and a value included
7466 in [-30,0] will filter edges. Default value is 0.
7468 @item chroma_radius, cr
7469 Set the chroma radius. The option value must be a float number in
7470 the range [0.1,5.0] that specifies the variance of the gaussian filter
7471 used to blur the image (slower if larger). Default value is 1.0.
7473 @item chroma_strength, cs
7474 Set the chroma strength. The option value must be a float number
7475 in the range [-1.0,1.0] that configures the blurring. A value included
7476 in [0.0,1.0] will blur the image whereas a value included in
7477 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7479 @item chroma_threshold, ct
7480 Set the chroma threshold used as a coefficient to determine
7481 whether a pixel should be blurred or not. The option value must be an
7482 integer in the range [-30,30]. A value of 0 will filter all the image,
7483 a value included in [0,30] will filter flat areas and a value included
7484 in [-30,0] will filter edges. Default value is 0.
7487 If a chroma option is not explicitly set, the corresponding luma value
7492 Convert between different stereoscopic image formats.
7494 The filters accept the following options:
7498 Set stereoscopic image format of input.
7500 Available values for input image formats are:
7503 side by side parallel (left eye left, right eye right)
7506 side by side crosseye (right eye left, left eye right)
7509 side by side parallel with half width resolution
7510 (left eye left, right eye right)
7513 side by side crosseye with half width resolution
7514 (right eye left, left eye right)
7517 above-below (left eye above, right eye below)
7520 above-below (right eye above, left eye below)
7523 above-below with half height resolution
7524 (left eye above, right eye below)
7527 above-below with half height resolution
7528 (right eye above, left eye below)
7531 alternating frames (left eye first, right eye second)
7534 alternating frames (right eye first, left eye second)
7536 Default value is @samp{sbsl}.
7540 Set stereoscopic image format of output.
7542 Available values for output image formats are all the input formats as well as:
7545 anaglyph red/blue gray
7546 (red filter on left eye, blue filter on right eye)
7549 anaglyph red/green gray
7550 (red filter on left eye, green filter on right eye)
7553 anaglyph red/cyan gray
7554 (red filter on left eye, cyan filter on right eye)
7557 anaglyph red/cyan half colored
7558 (red filter on left eye, cyan filter on right eye)
7561 anaglyph red/cyan color
7562 (red filter on left eye, cyan filter on right eye)
7565 anaglyph red/cyan color optimized with the least squares projection of dubois
7566 (red filter on left eye, cyan filter on right eye)
7569 anaglyph green/magenta gray
7570 (green filter on left eye, magenta filter on right eye)
7573 anaglyph green/magenta half colored
7574 (green filter on left eye, magenta filter on right eye)
7577 anaglyph green/magenta colored
7578 (green filter on left eye, magenta filter on right eye)
7581 anaglyph green/magenta color optimized with the least squares projection of dubois
7582 (green filter on left eye, magenta filter on right eye)
7585 anaglyph yellow/blue gray
7586 (yellow filter on left eye, blue filter on right eye)
7589 anaglyph yellow/blue half colored
7590 (yellow filter on left eye, blue filter on right eye)
7593 anaglyph yellow/blue colored
7594 (yellow filter on left eye, blue filter on right eye)
7597 anaglyph yellow/blue color optimized with the least squares projection of dubois
7598 (yellow filter on left eye, blue filter on right eye)
7601 interleaved rows (left eye has top row, right eye starts on next row)
7604 interleaved rows (right eye has top row, left eye starts on next row)
7607 mono output (left eye only)
7610 mono output (right eye only)
7613 Default value is @samp{arcd}.
7616 @subsection Examples
7620 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
7626 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
7634 Apply a simple postprocessing filter that compresses and decompresses the image
7635 at several (or - in the case of @option{quality} level @code{6} - all) shifts
7636 and average the results.
7638 The filter accepts the following options:
7642 Set quality. This option defines the number of levels for averaging. It accepts
7643 an integer in the range 0-6. If set to @code{0}, the filter will have no
7644 effect. A value of @code{6} means the higher quality. For each increment of
7645 that value the speed drops by a factor of approximately 2. Default value is
7649 Force a constant quantization parameter. If not set, the filter will use the QP
7650 from the video stream (if available).
7653 Set thresholding mode. Available modes are:
7657 Set hard thresholding (default).
7659 Set soft thresholding (better de-ringing effect, but likely blurrier).
7663 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
7664 option may cause flicker since the B-Frames have often larger QP. Default is
7665 @code{0} (not enabled).
7671 Draw subtitles on top of input video using the libass library.
7673 To enable compilation of this filter you need to configure FFmpeg with
7674 @code{--enable-libass}. This filter also requires a build with libavcodec and
7675 libavformat to convert the passed subtitles file to ASS (Advanced Substation
7676 Alpha) subtitles format.
7678 The filter accepts the following options:
7682 Set the filename of the subtitle file to read. It must be specified.
7685 Specify the size of the original video, the video for which the ASS file
7686 was composed. For the syntax of this option, check the "Video size" section in
7687 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
7688 this is necessary to correctly scale the fonts if the aspect ratio has been
7692 Set subtitles input character encoding. @code{subtitles} filter only. Only
7693 useful if not UTF-8.
7696 If the first key is not specified, it is assumed that the first value
7697 specifies the @option{filename}.
7699 For example, to render the file @file{sub.srt} on top of the input
7700 video, use the command:
7705 which is equivalent to:
7707 subtitles=filename=sub.srt
7712 Scale the input by 2x and smooth using the Super2xSaI (Scale and
7713 Interpolate) pixel art scaling algorithm.
7715 Useful for enlarging pixel art images without reducing sharpness.
7722 Apply telecine process to the video.
7724 This filter accepts the following options:
7733 The default value is @code{top}.
7737 A string of numbers representing the pulldown pattern you wish to apply.
7738 The default value is @code{23}.
7742 Some typical patterns:
7747 24p: 2332 (preferred)
7754 24p: 222222222223 ("Euro pulldown")
7760 Select the most representative frame in a given sequence of consecutive frames.
7762 The filter accepts the following options:
7766 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
7767 will pick one of them, and then handle the next batch of @var{n} frames until
7768 the end. Default is @code{100}.
7771 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
7772 value will result in a higher memory usage, so a high value is not recommended.
7774 @subsection Examples
7778 Extract one picture each 50 frames:
7784 Complete example of a thumbnail creation with @command{ffmpeg}:
7786 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
7792 Tile several successive frames together.
7794 The filter accepts the following options:
7799 Set the grid size (i.e. the number of lines and columns). For the syntax of
7800 this option, check the "Video size" section in the ffmpeg-utils manual.
7803 Set the maximum number of frames to render in the given area. It must be less
7804 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
7805 the area will be used.
7808 Set the outer border margin in pixels.
7811 Set the inner border thickness (i.e. the number of pixels between frames). For
7812 more advanced padding options (such as having different values for the edges),
7813 refer to the pad video filter.
7816 Specify the color of the unused areaFor the syntax of this option, check the
7817 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
7821 @subsection Examples
7825 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
7827 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
7829 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
7830 duplicating each output frame to accommodate the originally detected frame
7834 Display @code{5} pictures in an area of @code{3x2} frames,
7835 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
7836 mixed flat and named options:
7838 tile=3x2:nb_frames=5:padding=7:margin=2
7844 Perform various types of temporal field interlacing.
7846 Frames are counted starting from 1, so the first input frame is
7849 The filter accepts the following options:
7854 Specify the mode of the interlacing. This option can also be specified
7855 as a value alone. See below for a list of values for this option.
7857 Available values are:
7861 Move odd frames into the upper field, even into the lower field,
7862 generating a double height frame at half frame rate.
7865 Only output even frames, odd frames are dropped, generating a frame with
7866 unchanged height at half frame rate.
7869 Only output odd frames, even frames are dropped, generating a frame with
7870 unchanged height at half frame rate.
7873 Expand each frame to full height, but pad alternate lines with black,
7874 generating a frame with double height at the same input frame rate.
7876 @item interleave_top, 4
7877 Interleave the upper field from odd frames with the lower field from
7878 even frames, generating a frame with unchanged height at half frame rate.
7880 @item interleave_bottom, 5
7881 Interleave the lower field from odd frames with the upper field from
7882 even frames, generating a frame with unchanged height at half frame rate.
7884 @item interlacex2, 6
7885 Double frame rate with unchanged height. Frames are inserted each
7886 containing the second temporal field from the previous input frame and
7887 the first temporal field from the next input frame. This mode relies on
7888 the top_field_first flag. Useful for interlaced video displays with no
7889 field synchronisation.
7892 Numeric values are deprecated but are accepted for backward
7893 compatibility reasons.
7895 Default mode is @code{merge}.
7898 Specify flags influencing the filter process.
7900 Available value for @var{flags} is:
7903 @item low_pass_filter, vlfp
7904 Enable vertical low-pass filtering in the filter.
7905 Vertical low-pass filtering is required when creating an interlaced
7906 destination from a progressive source which contains high-frequency
7907 vertical detail. Filtering will reduce interlace 'twitter' and Moire
7910 Vertical low-pass filtering can only be enabled for @option{mode}
7911 @var{interleave_top} and @var{interleave_bottom}.
7918 Transpose rows with columns in the input video and optionally flip it.
7920 This filter accepts the following options:
7925 Specify the transposition direction.
7927 Can assume the following values:
7929 @item 0, 4, cclock_flip
7930 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
7938 Rotate by 90 degrees clockwise, that is:
7946 Rotate by 90 degrees counterclockwise, that is:
7953 @item 3, 7, clock_flip
7954 Rotate by 90 degrees clockwise and vertically flip, that is:
7962 For values between 4-7, the transposition is only done if the input
7963 video geometry is portrait and not landscape. These values are
7964 deprecated, the @code{passthrough} option should be used instead.
7966 Numerical values are deprecated, and should be dropped in favor of
7970 Do not apply the transposition if the input geometry matches the one
7971 specified by the specified value. It accepts the following values:
7974 Always apply transposition.
7976 Preserve portrait geometry (when @var{height} >= @var{width}).
7978 Preserve landscape geometry (when @var{width} >= @var{height}).
7981 Default value is @code{none}.
7984 For example to rotate by 90 degrees clockwise and preserve portrait
7987 transpose=dir=1:passthrough=portrait
7990 The command above can also be specified as:
7992 transpose=1:portrait
7996 Trim the input so that the output contains one continuous subpart of the input.
7998 This filter accepts the following options:
8001 Specify time of the start of the kept section, i.e. the frame with the
8002 timestamp @var{start} will be the first frame in the output.
8005 Specify time of the first frame that will be dropped, i.e. the frame
8006 immediately preceding the one with the timestamp @var{end} will be the last
8007 frame in the output.
8010 Same as @var{start}, except this option sets the start timestamp in timebase
8011 units instead of seconds.
8014 Same as @var{end}, except this option sets the end timestamp in timebase units
8018 Specify maximum duration of the output.
8021 Number of the first frame that should be passed to output.
8024 Number of the first frame that should be dropped.
8027 @option{start}, @option{end}, @option{duration} are expressed as time
8028 duration specifications, check the "Time duration" section in the
8029 ffmpeg-utils manual.
8031 Note that the first two sets of the start/end options and the @option{duration}
8032 option look at the frame timestamp, while the _frame variants simply count the
8033 frames that pass through the filter. Also note that this filter does not modify
8034 the timestamps. If you wish that the output timestamps start at zero, insert a
8035 setpts filter after the trim filter.
8037 If multiple start or end options are set, this filter tries to be greedy and
8038 keep all the frames that match at least one of the specified constraints. To keep
8039 only the part that matches all the constraints at once, chain multiple trim
8042 The defaults are such that all the input is kept. So it is possible to set e.g.
8043 just the end values to keep everything before the specified time.
8048 drop everything except the second minute of input
8050 ffmpeg -i INPUT -vf trim=60:120
8054 keep only the first second
8056 ffmpeg -i INPUT -vf trim=duration=1
8064 Sharpen or blur the input video.
8066 It accepts the following parameters:
8069 @item luma_msize_x, lx
8070 Set the luma matrix horizontal size. It must be an odd integer between
8071 3 and 63, default value is 5.
8073 @item luma_msize_y, ly
8074 Set the luma matrix vertical size. It must be an odd integer between 3
8075 and 63, default value is 5.
8077 @item luma_amount, la
8078 Set the luma effect strength. It can be a float number, reasonable
8079 values lay between -1.5 and 1.5.
8081 Negative values will blur the input video, while positive values will
8082 sharpen it, a value of zero will disable the effect.
8084 Default value is 1.0.
8086 @item chroma_msize_x, cx
8087 Set the chroma matrix horizontal size. It must be an odd integer
8088 between 3 and 63, default value is 5.
8090 @item chroma_msize_y, cy
8091 Set the chroma matrix vertical size. It must be an odd integer
8092 between 3 and 63, default value is 5.
8094 @item chroma_amount, ca
8095 Set the chroma effect strength. It can be a float number, reasonable
8096 values lay between -1.5 and 1.5.
8098 Negative values will blur the input video, while positive values will
8099 sharpen it, a value of zero will disable the effect.
8101 Default value is 0.0.
8104 If set to 1, specify using OpenCL capabilities, only available if
8105 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
8109 All parameters are optional and default to the equivalent of the
8110 string '5:5:1.0:5:5:0.0'.
8112 @subsection Examples
8116 Apply strong luma sharpen effect:
8118 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
8122 Apply strong blur of both luma and chroma parameters:
8124 unsharp=7:7:-2:7:7:-2
8128 @anchor{vidstabdetect}
8129 @section vidstabdetect
8131 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
8132 @ref{vidstabtransform} for pass 2.
8134 This filter generates a file with relative translation and rotation
8135 transform information about subsequent frames, which is then used by
8136 the @ref{vidstabtransform} filter.
8138 To enable compilation of this filter you need to configure FFmpeg with
8139 @code{--enable-libvidstab}.
8141 This filter accepts the following options:
8145 Set the path to the file used to write the transforms information.
8146 Default value is @file{transforms.trf}.
8149 Set how shaky the video is and how quick the camera is. It accepts an
8150 integer in the range 1-10, a value of 1 means little shakiness, a
8151 value of 10 means strong shakiness. Default value is 5.
8154 Set the accuracy of the detection process. It must be a value in the
8155 range 1-15. A value of 1 means low accuracy, a value of 15 means high
8156 accuracy. Default value is 15.
8159 Set stepsize of the search process. The region around minimum is
8160 scanned with 1 pixel resolution. Default value is 6.
8163 Set minimum contrast. Below this value a local measurement field is
8164 discarded. Must be a floating point value in the range 0-1. Default
8168 Set reference frame number for tripod mode.
8170 If enabled, the motion of the frames is compared to a reference frame
8171 in the filtered stream, identified by the specified number. The idea
8172 is to compensate all movements in a more-or-less static scene and keep
8173 the camera view absolutely still.
8175 If set to 0, it is disabled. The frames are counted starting from 1.
8178 Show fields and transforms in the resulting frames. It accepts an
8179 integer in the range 0-2. Default value is 0, which disables any
8183 @subsection Examples
8193 Analyze strongly shaky movie and put the results in file
8194 @file{mytransforms.trf}:
8196 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
8200 Visualize the result of internal transformations in the resulting
8203 vidstabdetect=show=1
8207 Analyze a video with medium shakiness using @command{ffmpeg}:
8209 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
8213 @anchor{vidstabtransform}
8214 @section vidstabtransform
8216 Video stabilization/deshaking: pass 2 of 2,
8217 see @ref{vidstabdetect} for pass 1.
8219 Read a file with transform information for each frame and
8220 apply/compensate them. Together with the @ref{vidstabdetect}
8221 filter this can be used to deshake videos. See also
8222 @url{http://public.hronopik.de/vid.stab}. It is important to also use
8223 the unsharp filter, see below.
8225 To enable compilation of this filter you need to configure FFmpeg with
8226 @code{--enable-libvidstab}.
8232 Set path to the file used to read the transforms. Default value is
8233 @file{transforms.trf}).
8236 Set the number of frames (value*2 + 1) used for lowpass filtering the
8237 camera movements. Default value is 10.
8239 For example a number of 10 means that 21 frames are used (10 in the
8240 past and 10 in the future) to smoothen the motion in the video. A
8241 larger values leads to a smoother video, but limits the acceleration
8242 of the camera (pan/tilt movements). 0 is a special case where a
8243 static camera is simulated.
8246 Set the camera path optimization algorithm.
8248 Accepted values are:
8251 gaussian kernel low-pass filter on camera motion (default)
8253 averaging on transformations
8257 Set maximal number of pixels to translate frames. Default value is -1,
8261 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
8262 value is -1, meaning no limit.
8265 Specify how to deal with borders that may be visible due to movement
8268 Available values are:
8271 keep image information from previous frame (default)
8273 fill the border black
8277 Invert transforms if set to 1. Default value is 0.
8280 Consider transforms as relative to previsou frame if set to 1,
8281 absolute if set to 0. Default value is 0.
8284 Set percentage to zoom. A positive value will result in a zoom-in
8285 effect, a negative value in a zoom-out effect. Default value is 0 (no
8289 Set optimal zooming to avoid borders.
8291 Accepted values are:
8296 optimal static zoom value is determined (only very strong movements
8297 will lead to visible borders) (default)
8299 optimal adaptive zoom value is determined (no borders will be
8300 visible), see @option{zoomspeed}
8303 Note that the value given at zoom is added to the one calculated here.
8306 Set percent to zoom maximally each frame (enabled when
8307 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
8311 Specify type of interpolation.
8313 Available values are:
8318 linear only horizontal
8320 linear in both directions (default)
8322 cubic in both directions (slow)
8326 Enable virtual tripod mode if set to 1, which is equivalent to
8327 @code{relative=0:smoothing=0}. Default value is 0.
8329 Use also @code{tripod} option of @ref{vidstabdetect}.
8332 Increase log verbosity if set to 1. Also the detected global motions
8333 are written to the temporary file @file{global_motions.trf}. Default
8337 @subsection Examples
8341 Use @command{ffmpeg} for a typical stabilization with default values:
8343 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
8346 Note the use of the unsharp filter which is always recommended.
8349 Zoom in a bit more and load transform data from a given file:
8351 vidstabtransform=zoom=5:input="mytransforms.trf"
8355 Smoothen the video even more:
8357 vidstabtransform=smoothing=30
8363 Flip the input video vertically.
8365 For example, to vertically flip a video with @command{ffmpeg}:
8367 ffmpeg -i in.avi -vf "vflip" out.avi
8372 Make or reverse a natural vignetting effect.
8374 The filter accepts the following options:
8378 Set lens angle expression as a number of radians.
8380 The value is clipped in the @code{[0,PI/2]} range.
8382 Default value: @code{"PI/5"}
8386 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
8390 Set forward/backward mode.
8392 Available modes are:
8395 The larger the distance from the central point, the darker the image becomes.
8398 The larger the distance from the central point, the brighter the image becomes.
8399 This can be used to reverse a vignette effect, though there is no automatic
8400 detection to extract the lens @option{angle} and other settings (yet). It can
8401 also be used to create a burning effect.
8404 Default value is @samp{forward}.
8407 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
8409 It accepts the following values:
8412 Evaluate expressions only once during the filter initialization.
8415 Evaluate expressions for each incoming frame. This is way slower than the
8416 @samp{init} mode since it requires all the scalers to be re-computed, but it
8417 allows advanced dynamic expressions.
8420 Default value is @samp{init}.
8423 Set dithering to reduce the circular banding effects. Default is @code{1}
8427 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
8428 Setting this value to the SAR of the input will make a rectangular vignetting
8429 following the dimensions of the video.
8431 Default is @code{1/1}.
8434 @subsection Expressions
8436 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
8437 following parameters.
8442 input width and height
8445 the number of input frame, starting from 0
8448 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
8449 @var{TB} units, NAN if undefined
8452 frame rate of the input video, NAN if the input frame rate is unknown
8455 the PTS (Presentation TimeStamp) of the filtered video frame,
8456 expressed in seconds, NAN if undefined
8459 time base of the input video
8463 @subsection Examples
8467 Apply simple strong vignetting effect:
8473 Make a flickering vignetting:
8475 vignette='PI/4+random(1)*PI/50':eval=frame
8482 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
8483 Deinterlacing Filter").
8485 Based on the process described by Martin Weston for BBC R&D, and
8486 implemented based on the de-interlace algorithm written by Jim
8487 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
8488 uses filter coefficients calculated by BBC R&D.
8490 There are two sets of filter coefficients, so called "simple":
8491 and "complex". Which set of filter coefficients is used can
8492 be set by passing an optional parameter:
8496 Set the interlacing filter coefficients. Accepts one of the following values:
8500 Simple filter coefficient set.
8502 More-complex filter coefficient set.
8504 Default value is @samp{complex}.
8507 Specify which frames to deinterlace. Accept one of the following values:
8511 Deinterlace all frames,
8513 Only deinterlace frames marked as interlaced.
8516 Default value is @samp{all}.
8522 Deinterlace the input video ("yadif" means "yet another deinterlacing
8525 This filter accepts the following options:
8531 The interlacing mode to adopt, accepts one of the following values:
8535 output 1 frame for each frame
8537 output 1 frame for each field
8538 @item 2, send_frame_nospatial
8539 like @code{send_frame} but skip spatial interlacing check
8540 @item 3, send_field_nospatial
8541 like @code{send_field} but skip spatial interlacing check
8544 Default value is @code{send_frame}.
8547 The picture field parity assumed for the input interlaced video, accepts one of
8548 the following values:
8552 assume top field first
8554 assume bottom field first
8556 enable automatic detection
8559 Default value is @code{auto}.
8560 If interlacing is unknown or decoder does not export this information,
8561 top field first will be assumed.
8564 Specify which frames to deinterlace. Accept one of the following
8569 deinterlace all frames
8571 only deinterlace frames marked as interlaced
8574 Default value is @code{all}.
8577 @c man end VIDEO FILTERS
8579 @chapter Video Sources
8580 @c man begin VIDEO SOURCES
8582 Below is a description of the currently available video sources.
8586 Buffer video frames, and make them available to the filter chain.
8588 This source is mainly intended for a programmatic use, in particular
8589 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
8591 This source accepts the following options:
8596 Specify the size (width and height) of the buffered video frames. For the
8597 syntax of this option, check the "Video size" section in the ffmpeg-utils
8607 A string representing the pixel format of the buffered video frames.
8608 It may be a number corresponding to a pixel format, or a pixel format
8612 Specify the timebase assumed by the timestamps of the buffered frames.
8615 Specify the frame rate expected for the video stream.
8617 @item pixel_aspect, sar
8618 Specify the sample aspect ratio assumed by the video frames.
8621 Specify the optional parameters to be used for the scale filter which
8622 is automatically inserted when an input change is detected in the
8623 input size or format.
8628 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
8631 will instruct the source to accept video frames with size 320x240 and
8632 with format "yuv410p", assuming 1/24 as the timestamps timebase and
8633 square pixels (1:1 sample aspect ratio).
8634 Since the pixel format with name "yuv410p" corresponds to the number 6
8635 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
8636 this example corresponds to:
8638 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
8641 Alternatively, the options can be specified as a flat string, but this
8642 syntax is deprecated:
8644 @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}]
8648 Create a pattern generated by an elementary cellular automaton.
8650 The initial state of the cellular automaton can be defined through the
8651 @option{filename}, and @option{pattern} options. If such options are
8652 not specified an initial state is created randomly.
8654 At each new frame a new row in the video is filled with the result of
8655 the cellular automaton next generation. The behavior when the whole
8656 frame is filled is defined by the @option{scroll} option.
8658 This source accepts the following options:
8662 Read the initial cellular automaton state, i.e. the starting row, from
8664 In the file, each non-whitespace character is considered an alive
8665 cell, a newline will terminate the row, and further characters in the
8666 file will be ignored.
8669 Read the initial cellular automaton state, i.e. the starting row, from
8670 the specified string.
8672 Each non-whitespace character in the string is considered an alive
8673 cell, a newline will terminate the row, and further characters in the
8674 string will be ignored.
8677 Set the video rate, that is the number of frames generated per second.
8680 @item random_fill_ratio, ratio
8681 Set the random fill ratio for the initial cellular automaton row. It
8682 is a floating point number value ranging from 0 to 1, defaults to
8685 This option is ignored when a file or a pattern is specified.
8687 @item random_seed, seed
8688 Set the seed for filling randomly the initial row, must be an integer
8689 included between 0 and UINT32_MAX. If not specified, or if explicitly
8690 set to -1, the filter will try to use a good random seed on a best
8694 Set the cellular automaton rule, it is a number ranging from 0 to 255.
8695 Default value is 110.
8698 Set the size of the output video. For the syntax of this option, check
8699 the "Video size" section in the ffmpeg-utils manual.
8701 If @option{filename} or @option{pattern} is specified, the size is set
8702 by default to the width of the specified initial state row, and the
8703 height is set to @var{width} * PHI.
8705 If @option{size} is set, it must contain the width of the specified
8706 pattern string, and the specified pattern will be centered in the
8709 If a filename or a pattern string is not specified, the size value
8710 defaults to "320x518" (used for a randomly generated initial state).
8713 If set to 1, scroll the output upward when all the rows in the output
8714 have been already filled. If set to 0, the new generated row will be
8715 written over the top row just after the bottom row is filled.
8718 @item start_full, full
8719 If set to 1, completely fill the output with generated rows before
8720 outputting the first frame.
8721 This is the default behavior, for disabling set the value to 0.
8724 If set to 1, stitch the left and right row edges together.
8725 This is the default behavior, for disabling set the value to 0.
8728 @subsection Examples
8732 Read the initial state from @file{pattern}, and specify an output of
8735 cellauto=f=pattern:s=200x400
8739 Generate a random initial row with a width of 200 cells, with a fill
8742 cellauto=ratio=2/3:s=200x200
8746 Create a pattern generated by rule 18 starting by a single alive cell
8747 centered on an initial row with width 100:
8749 cellauto=p=@@:s=100x400:full=0:rule=18
8753 Specify a more elaborated initial pattern:
8755 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
8762 Generate a Mandelbrot set fractal, and progressively zoom towards the
8763 point specified with @var{start_x} and @var{start_y}.
8765 This source accepts the following options:
8770 Set the terminal pts value. Default value is 400.
8773 Set the terminal scale value.
8774 Must be a floating point value. Default value is 0.3.
8777 Set the inner coloring mode, that is the algorithm used to draw the
8778 Mandelbrot fractal internal region.
8780 It shall assume one of the following values:
8785 Show time until convergence.
8787 Set color based on point closest to the origin of the iterations.
8792 Default value is @var{mincol}.
8795 Set the bailout value. Default value is 10.0.
8798 Set the maximum of iterations performed by the rendering
8799 algorithm. Default value is 7189.
8802 Set outer coloring mode.
8803 It shall assume one of following values:
8805 @item iteration_count
8806 Set iteration cound mode.
8807 @item normalized_iteration_count
8808 set normalized iteration count mode.
8810 Default value is @var{normalized_iteration_count}.
8813 Set frame rate, expressed as number of frames per second. Default
8817 Set frame size. For the syntax of this option, check the "Video
8818 size" section in the ffmpeg-utils manual. Default value is "640x480".
8821 Set the initial scale value. Default value is 3.0.
8824 Set the initial x position. Must be a floating point value between
8825 -100 and 100. Default value is -0.743643887037158704752191506114774.
8828 Set the initial y position. Must be a floating point value between
8829 -100 and 100. Default value is -0.131825904205311970493132056385139.
8834 Generate various test patterns, as generated by the MPlayer test filter.
8836 The size of the generated video is fixed, and is 256x256.
8837 This source is useful in particular for testing encoding features.
8839 This source accepts the following options:
8844 Specify the frame rate of the sourced video, as the number of frames
8845 generated per second. It has to be a string in the format
8846 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
8847 number or a valid video frame rate abbreviation. The default value is
8851 Set the video duration of the sourced video. The accepted syntax is:
8856 See also the function @code{av_parse_time()}.
8858 If not specified, or the expressed duration is negative, the video is
8859 supposed to be generated forever.
8863 Set the number or the name of the test to perform. Supported tests are:
8878 Default value is "all", which will cycle through the list of all tests.
8881 For example the following:
8886 will generate a "dc_luma" test pattern.
8890 Provide a frei0r source.
8892 To enable compilation of this filter you need to install the frei0r
8893 header and configure FFmpeg with @code{--enable-frei0r}.
8895 This source accepts the following options:
8900 The size of the video to generate. For the syntax of this option, check the
8901 "Video size" section in the ffmpeg-utils manual.
8904 Framerate of the generated video, may be a string of the form
8905 @var{num}/@var{den} or a frame rate abbreviation.
8908 The name to the frei0r source to load. For more information regarding frei0r and
8909 how to set the parameters read the section @ref{frei0r} in the description of
8913 A '|'-separated list of parameters to pass to the frei0r source.
8917 For example, to generate a frei0r partik0l source with size 200x200
8918 and frame rate 10 which is overlayed on the overlay filter main input:
8920 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
8925 Generate a life pattern.
8927 This source is based on a generalization of John Conway's life game.
8929 The sourced input represents a life grid, each pixel represents a cell
8930 which can be in one of two possible states, alive or dead. Every cell
8931 interacts with its eight neighbours, which are the cells that are
8932 horizontally, vertically, or diagonally adjacent.
8934 At each interaction the grid evolves according to the adopted rule,
8935 which specifies the number of neighbor alive cells which will make a
8936 cell stay alive or born. The @option{rule} option allows one to specify
8939 This source accepts the following options:
8943 Set the file from which to read the initial grid state. In the file,
8944 each non-whitespace character is considered an alive cell, and newline
8945 is used to delimit the end of each row.
8947 If this option is not specified, the initial grid is generated
8951 Set the video rate, that is the number of frames generated per second.
8954 @item random_fill_ratio, ratio
8955 Set the random fill ratio for the initial random grid. It is a
8956 floating point number value ranging from 0 to 1, defaults to 1/PHI.
8957 It is ignored when a file is specified.
8959 @item random_seed, seed
8960 Set the seed for filling the initial random grid, must be an integer
8961 included between 0 and UINT32_MAX. If not specified, or if explicitly
8962 set to -1, the filter will try to use a good random seed on a best
8968 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
8969 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
8970 @var{NS} specifies the number of alive neighbor cells which make a
8971 live cell stay alive, and @var{NB} the number of alive neighbor cells
8972 which make a dead cell to become alive (i.e. to "born").
8973 "s" and "b" can be used in place of "S" and "B", respectively.
8975 Alternatively a rule can be specified by an 18-bits integer. The 9
8976 high order bits are used to encode the next cell state if it is alive
8977 for each number of neighbor alive cells, the low order bits specify
8978 the rule for "borning" new cells. Higher order bits encode for an
8979 higher number of neighbor cells.
8980 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
8981 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
8983 Default value is "S23/B3", which is the original Conway's game of life
8984 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
8985 cells, and will born a new cell if there are three alive cells around
8989 Set the size of the output video. For the syntax of this option, check the
8990 "Video size" section in the ffmpeg-utils manual.
8992 If @option{filename} is specified, the size is set by default to the
8993 same size of the input file. If @option{size} is set, it must contain
8994 the size specified in the input file, and the initial grid defined in
8995 that file is centered in the larger resulting area.
8997 If a filename is not specified, the size value defaults to "320x240"
8998 (used for a randomly generated initial grid).
9001 If set to 1, stitch the left and right grid edges together, and the
9002 top and bottom edges also. Defaults to 1.
9005 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
9006 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
9007 value from 0 to 255.
9010 Set the color of living (or new born) cells.
9013 Set the color of dead cells. If @option{mold} is set, this is the first color
9014 used to represent a dead cell.
9017 Set mold color, for definitely dead and moldy cells.
9019 For the syntax of these 3 color options, check the "Color" section in the
9020 ffmpeg-utils manual.
9023 @subsection Examples
9027 Read a grid from @file{pattern}, and center it on a grid of size
9030 life=f=pattern:s=300x300
9034 Generate a random grid of size 200x200, with a fill ratio of 2/3:
9036 life=ratio=2/3:s=200x200
9040 Specify a custom rule for evolving a randomly generated grid:
9046 Full example with slow death effect (mold) using @command{ffplay}:
9048 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
9053 @anchor{haldclutsrc}
9057 @anchor{smptehdbars}
9059 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
9061 The @code{color} source provides an uniformly colored input.
9063 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
9064 @ref{haldclut} filter.
9066 The @code{nullsrc} source returns unprocessed video frames. It is
9067 mainly useful to be employed in analysis / debugging tools, or as the
9068 source for filters which ignore the input data.
9070 The @code{rgbtestsrc} source generates an RGB test pattern useful for
9071 detecting RGB vs BGR issues. You should see a red, green and blue
9072 stripe from top to bottom.
9074 The @code{smptebars} source generates a color bars pattern, based on
9075 the SMPTE Engineering Guideline EG 1-1990.
9077 The @code{smptehdbars} source generates a color bars pattern, based on
9078 the SMPTE RP 219-2002.
9080 The @code{testsrc} source generates a test video pattern, showing a
9081 color pattern, a scrolling gradient and a timestamp. This is mainly
9082 intended for testing purposes.
9084 The sources accept the following options:
9089 Specify the color of the source, only available in the @code{color}
9090 source. For the syntax of this option, check the "Color" section in the
9091 ffmpeg-utils manual.
9094 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
9095 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
9096 pixels to be used as identity matrix for 3D lookup tables. Each component is
9097 coded on a @code{1/(N*N)} scale.
9100 Specify the size of the sourced video. For the syntax of this option, check the
9101 "Video size" section in the ffmpeg-utils manual. The default value is
9104 This option is not available with the @code{haldclutsrc} filter.
9107 Specify the frame rate of the sourced video, as the number of frames
9108 generated per second. It has to be a string in the format
9109 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
9110 number or a valid video frame rate abbreviation. The default value is
9114 Set the sample aspect ratio of the sourced video.
9117 Set the video duration of the sourced video. The accepted syntax is:
9119 [-]HH[:MM[:SS[.m...]]]
9122 See also the function @code{av_parse_time()}.
9124 If not specified, or the expressed duration is negative, the video is
9125 supposed to be generated forever.
9128 Set the number of decimals to show in the timestamp, only available in the
9129 @code{testsrc} source.
9131 The displayed timestamp value will correspond to the original
9132 timestamp value multiplied by the power of 10 of the specified
9133 value. Default value is 0.
9136 For example the following:
9138 testsrc=duration=5.3:size=qcif:rate=10
9141 will generate a video with a duration of 5.3 seconds, with size
9142 176x144 and a frame rate of 10 frames per second.
9144 The following graph description will generate a red source
9145 with an opacity of 0.2, with size "qcif" and a frame rate of 10
9148 color=c=red@@0.2:s=qcif:r=10
9151 If the input content is to be ignored, @code{nullsrc} can be used. The
9152 following command generates noise in the luminance plane by employing
9153 the @code{geq} filter:
9155 nullsrc=s=256x256, geq=random(1)*255:128:128
9158 @subsection Commands
9160 The @code{color} source supports the following commands:
9164 Set the color of the created image. Accepts the same syntax of the
9165 corresponding @option{color} option.
9168 @c man end VIDEO SOURCES
9170 @chapter Video Sinks
9171 @c man begin VIDEO SINKS
9173 Below is a description of the currently available video sinks.
9177 Buffer video frames, and make them available to the end of the filter
9180 This sink is mainly intended for a programmatic use, in particular
9181 through the interface defined in @file{libavfilter/buffersink.h}
9182 or the options system.
9184 It accepts a pointer to an AVBufferSinkContext structure, which
9185 defines the incoming buffers' formats, to be passed as the opaque
9186 parameter to @code{avfilter_init_filter} for initialization.
9190 Null video sink, do absolutely nothing with the input video. It is
9191 mainly useful as a template and to be employed in analysis / debugging
9194 @c man end VIDEO SINKS
9196 @chapter Multimedia Filters
9197 @c man begin MULTIMEDIA FILTERS
9199 Below is a description of the currently available multimedia filters.
9201 @section avectorscope
9203 Convert input audio to a video output, representing the audio vector
9206 The filter is used to measure the difference between channels of stereo
9207 audio stream. A monoaural signal, consisting of identical left and right
9208 signal, results in straight vertical line. Any stereo separation is visible
9209 as a deviation from this line, creating a Lissajous figure.
9210 If the straight (or deviation from it) but horizontal line appears this
9211 indicates that the left and right channels are out of phase.
9213 The filter accepts the following options:
9217 Set the vectorscope mode.
9219 Available values are:
9222 Lissajous rotated by 45 degrees.
9225 Same as above but not rotated.
9228 Default value is @samp{lissajous}.
9231 Set the video size for the output. For the syntax of this option, check the "Video size"
9232 section in the ffmpeg-utils manual. Default value is @code{400x400}.
9235 Set the output frame rate. Default value is @code{25}.
9240 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
9241 Allowed range is @code{[0, 255]}.
9246 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
9247 Allowed range is @code{[0, 255]}.
9250 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
9253 @subsection Examples
9257 Complete example using @command{ffplay}:
9259 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9260 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
9266 Concatenate audio and video streams, joining them together one after the
9269 The filter works on segments of synchronized video and audio streams. All
9270 segments must have the same number of streams of each type, and that will
9271 also be the number of streams at output.
9273 The filter accepts the following options:
9278 Set the number of segments. Default is 2.
9281 Set the number of output video streams, that is also the number of video
9282 streams in each segment. Default is 1.
9285 Set the number of output audio streams, that is also the number of video
9286 streams in each segment. Default is 0.
9289 Activate unsafe mode: do not fail if segments have a different format.
9293 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
9294 @var{a} audio outputs.
9296 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
9297 segment, in the same order as the outputs, then the inputs for the second
9300 Related streams do not always have exactly the same duration, for various
9301 reasons including codec frame size or sloppy authoring. For that reason,
9302 related synchronized streams (e.g. a video and its audio track) should be
9303 concatenated at once. The concat filter will use the duration of the longest
9304 stream in each segment (except the last one), and if necessary pad shorter
9305 audio streams with silence.
9307 For this filter to work correctly, all segments must start at timestamp 0.
9309 All corresponding streams must have the same parameters in all segments; the
9310 filtering system will automatically select a common pixel format for video
9311 streams, and a common sample format, sample rate and channel layout for
9312 audio streams, but other settings, such as resolution, must be converted
9313 explicitly by the user.
9315 Different frame rates are acceptable but will result in variable frame rate
9316 at output; be sure to configure the output file to handle it.
9318 @subsection Examples
9322 Concatenate an opening, an episode and an ending, all in bilingual version
9323 (video in stream 0, audio in streams 1 and 2):
9325 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
9326 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
9327 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
9328 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
9332 Concatenate two parts, handling audio and video separately, using the
9333 (a)movie sources, and adjusting the resolution:
9335 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
9336 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
9337 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
9339 Note that a desync will happen at the stitch if the audio and video streams
9340 do not have exactly the same duration in the first file.
9346 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
9347 it unchanged. By default, it logs a message at a frequency of 10Hz with the
9348 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
9349 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
9351 The filter also has a video output (see the @var{video} option) with a real
9352 time graph to observe the loudness evolution. The graphic contains the logged
9353 message mentioned above, so it is not printed anymore when this option is set,
9354 unless the verbose logging is set. The main graphing area contains the
9355 short-term loudness (3 seconds of analysis), and the gauge on the right is for
9356 the momentary loudness (400 milliseconds).
9358 More information about the Loudness Recommendation EBU R128 on
9359 @url{http://tech.ebu.ch/loudness}.
9361 The filter accepts the following options:
9366 Activate the video output. The audio stream is passed unchanged whether this
9367 option is set or no. The video stream will be the first output stream if
9368 activated. Default is @code{0}.
9371 Set the video size. This option is for video only. For the syntax of this
9372 option, check the "Video size" section in the ffmpeg-utils manual. Default
9373 and minimum resolution is @code{640x480}.
9376 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
9377 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
9378 other integer value between this range is allowed.
9381 Set metadata injection. If set to @code{1}, the audio input will be segmented
9382 into 100ms output frames, each of them containing various loudness information
9383 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
9385 Default is @code{0}.
9388 Force the frame logging level.
9390 Available values are:
9393 information logging level
9395 verbose logging level
9398 By default, the logging level is set to @var{info}. If the @option{video} or
9399 the @option{metadata} options are set, it switches to @var{verbose}.
9404 Available modes can be cumulated (the option is a @code{flag} type). Possible
9408 Disable any peak mode (default).
9410 Enable sample-peak mode.
9412 Simple peak mode looking for the higher sample value. It logs a message
9413 for sample-peak (identified by @code{SPK}).
9415 Enable true-peak mode.
9417 If enabled, the peak lookup is done on an over-sampled version of the input
9418 stream for better peak accuracy. It logs a message for true-peak.
9419 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
9420 This mode requires a build with @code{libswresample}.
9425 @subsection Examples
9429 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
9431 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
9435 Run an analysis with @command{ffmpeg}:
9437 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
9441 @section interleave, ainterleave
9443 Temporally interleave frames from several inputs.
9445 @code{interleave} works with video inputs, @code{ainterleave} with audio.
9447 These filters read frames from several inputs and send the oldest
9448 queued frame to the output.
9450 Input streams must have a well defined, monotonically increasing frame
9453 In order to submit one frame to output, these filters need to enqueue
9454 at least one frame for each input, so they cannot work in case one
9455 input is not yet terminated and will not receive incoming frames.
9457 For example consider the case when one input is a @code{select} filter
9458 which always drop input frames. The @code{interleave} filter will keep
9459 reading from that input, but it will never be able to send new frames
9460 to output until the input will send an end-of-stream signal.
9462 Also, depending on inputs synchronization, the filters will drop
9463 frames in case one input receives more frames than the other ones, and
9464 the queue is already filled.
9466 These filters accept the following options:
9470 Set the number of different inputs, it is 2 by default.
9473 @subsection Examples
9477 Interleave frames belonging to different streams using @command{ffmpeg}:
9479 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
9483 Add flickering blur effect:
9485 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
9489 @section perms, aperms
9491 Set read/write permissions for the output frames.
9493 These filters are mainly aimed at developers to test direct path in the
9494 following filter in the filtergraph.
9496 The filters accept the following options:
9500 Select the permissions mode.
9502 It accepts the following values:
9505 Do nothing. This is the default.
9507 Set all the output frames read-only.
9509 Set all the output frames directly writable.
9511 Make the frame read-only if writable, and writable if read-only.
9513 Set each output frame read-only or writable randomly.
9517 Set the seed for the @var{random} mode, must be an integer included between
9518 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
9519 @code{-1}, the filter will try to use a good random seed on a best effort
9523 Note: in case of auto-inserted filter between the permission filter and the
9524 following one, the permission might not be received as expected in that
9525 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
9526 perms/aperms filter can avoid this problem.
9528 @section select, aselect
9530 Select frames to pass in output.
9532 This filter accepts the following options:
9537 Set expression, which is evaluated for each input frame.
9539 If the expression is evaluated to zero, the frame is discarded.
9541 If the evaluation result is negative or NaN, the frame is sent to the
9542 first output; otherwise it is sent to the output with index
9543 @code{ceil(val)-1}, assuming that the input index starts from 0.
9545 For example a value of @code{1.2} corresponds to the output with index
9546 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
9549 Set the number of outputs. The output to which to send the selected
9550 frame is based on the result of the evaluation. Default value is 1.
9553 The expression can contain the following constants:
9557 the sequential number of the filtered frame, starting from 0
9560 the sequential number of the selected frame, starting from 0
9562 @item prev_selected_n
9563 the sequential number of the last selected frame, NAN if undefined
9566 timebase of the input timestamps
9569 the PTS (Presentation TimeStamp) of the filtered video frame,
9570 expressed in @var{TB} units, NAN if undefined
9573 the PTS (Presentation TimeStamp) of the filtered video frame,
9574 expressed in seconds, NAN if undefined
9577 the PTS of the previously filtered video frame, NAN if undefined
9579 @item prev_selected_pts
9580 the PTS of the last previously filtered video frame, NAN if undefined
9582 @item prev_selected_t
9583 the PTS of the last previously selected video frame, NAN if undefined
9586 the PTS of the first video frame in the video, NAN if undefined
9589 the time of the first video frame in the video, NAN if undefined
9591 @item pict_type @emph{(video only)}
9592 the type of the filtered frame, can assume one of the following
9604 @item interlace_type @emph{(video only)}
9605 the frame interlace type, can assume one of the following values:
9608 the frame is progressive (not interlaced)
9610 the frame is top-field-first
9612 the frame is bottom-field-first
9615 @item consumed_sample_n @emph{(audio only)}
9616 the number of selected samples before the current frame
9618 @item samples_n @emph{(audio only)}
9619 the number of samples in the current frame
9621 @item sample_rate @emph{(audio only)}
9622 the input sample rate
9625 1 if the filtered frame is a key-frame, 0 otherwise
9628 the position in the file of the filtered frame, -1 if the information
9629 is not available (e.g. for synthetic video)
9631 @item scene @emph{(video only)}
9632 value between 0 and 1 to indicate a new scene; a low value reflects a low
9633 probability for the current frame to introduce a new scene, while a higher
9634 value means the current frame is more likely to be one (see the example below)
9638 The default value of the select expression is "1".
9640 @subsection Examples
9644 Select all frames in input:
9649 The example above is the same as:
9661 Select only I-frames:
9663 select='eq(pict_type\,I)'
9667 Select one frame every 100:
9669 select='not(mod(n\,100))'
9673 Select only frames contained in the 10-20 time interval:
9675 select=between(t\,10\,20)
9679 Select only I frames contained in the 10-20 time interval:
9681 select=between(t\,10\,20)*eq(pict_type\,I)
9685 Select frames with a minimum distance of 10 seconds:
9687 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
9691 Use aselect to select only audio frames with samples number > 100:
9693 aselect='gt(samples_n\,100)'
9697 Create a mosaic of the first scenes:
9699 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
9702 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
9706 Send even and odd frames to separate outputs, and compose them:
9708 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
9712 @section sendcmd, asendcmd
9714 Send commands to filters in the filtergraph.
9716 These filters read commands to be sent to other filters in the
9719 @code{sendcmd} must be inserted between two video filters,
9720 @code{asendcmd} must be inserted between two audio filters, but apart
9721 from that they act the same way.
9723 The specification of commands can be provided in the filter arguments
9724 with the @var{commands} option, or in a file specified by the
9725 @var{filename} option.
9727 These filters accept the following options:
9730 Set the commands to be read and sent to the other filters.
9732 Set the filename of the commands to be read and sent to the other
9736 @subsection Commands syntax
9738 A commands description consists of a sequence of interval
9739 specifications, comprising a list of commands to be executed when a
9740 particular event related to that interval occurs. The occurring event
9741 is typically the current frame time entering or leaving a given time
9744 An interval is specified by the following syntax:
9746 @var{START}[-@var{END}] @var{COMMANDS};
9749 The time interval is specified by the @var{START} and @var{END} times.
9750 @var{END} is optional and defaults to the maximum time.
9752 The current frame time is considered within the specified interval if
9753 it is included in the interval [@var{START}, @var{END}), that is when
9754 the time is greater or equal to @var{START} and is lesser than
9757 @var{COMMANDS} consists of a sequence of one or more command
9758 specifications, separated by ",", relating to that interval. The
9759 syntax of a command specification is given by:
9761 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
9764 @var{FLAGS} is optional and specifies the type of events relating to
9765 the time interval which enable sending the specified command, and must
9766 be a non-null sequence of identifier flags separated by "+" or "|" and
9767 enclosed between "[" and "]".
9769 The following flags are recognized:
9772 The command is sent when the current frame timestamp enters the
9773 specified interval. In other words, the command is sent when the
9774 previous frame timestamp was not in the given interval, and the
9778 The command is sent when the current frame timestamp leaves the
9779 specified interval. In other words, the command is sent when the
9780 previous frame timestamp was in the given interval, and the
9784 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
9787 @var{TARGET} specifies the target of the command, usually the name of
9788 the filter class or a specific filter instance name.
9790 @var{COMMAND} specifies the name of the command for the target filter.
9792 @var{ARG} is optional and specifies the optional list of argument for
9793 the given @var{COMMAND}.
9795 Between one interval specification and another, whitespaces, or
9796 sequences of characters starting with @code{#} until the end of line,
9797 are ignored and can be used to annotate comments.
9799 A simplified BNF description of the commands specification syntax
9802 @var{COMMAND_FLAG} ::= "enter" | "leave"
9803 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
9804 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
9805 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
9806 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
9807 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
9810 @subsection Examples
9814 Specify audio tempo change at second 4:
9816 asendcmd=c='4.0 atempo tempo 1.5',atempo
9820 Specify a list of drawtext and hue commands in a file.
9822 # show text in the interval 5-10
9823 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
9824 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
9826 # desaturate the image in the interval 15-20
9827 15.0-20.0 [enter] hue s 0,
9828 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
9830 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
9832 # apply an exponential saturation fade-out effect, starting from time 25
9833 25 [enter] hue s exp(25-t)
9836 A filtergraph allowing to read and process the above command list
9837 stored in a file @file{test.cmd}, can be specified with:
9839 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
9844 @section setpts, asetpts
9846 Change the PTS (presentation timestamp) of the input frames.
9848 @code{setpts} works on video frames, @code{asetpts} on audio frames.
9850 This filter accepts the following options:
9855 The expression which is evaluated for each frame to construct its timestamp.
9859 The expression is evaluated through the eval API and can contain the following
9864 frame rate, only defined for constant frame-rate video
9867 the presentation timestamp in input
9870 the count of the input frame for video or the number of consumed samples,
9871 not including the current frame for audio, starting from 0.
9873 @item NB_CONSUMED_SAMPLES
9874 the number of consumed samples, not including the current frame (only
9878 the number of samples in the current frame (only audio)
9880 @item SAMPLE_RATE, SR
9884 the PTS of the first frame
9887 the time in seconds of the first frame
9890 tell if the current frame is interlaced
9893 the time in seconds of the current frame
9896 original position in the file of the frame, or undefined if undefined
9897 for the current frame
9903 previous input time in seconds
9909 previous output time in seconds
9912 wallclock (RTC) time in microseconds. This is deprecated, use time(0)
9916 wallclock (RTC) time at the start of the movie in microseconds
9919 timebase of the input timestamps
9923 @subsection Examples
9927 Start counting PTS from zero
9933 Apply fast motion effect:
9939 Apply slow motion effect:
9945 Set fixed rate of 25 frames per second:
9951 Set fixed rate 25 fps with some jitter:
9953 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
9957 Apply an offset of 10 seconds to the input PTS:
9963 Generate timestamps from a "live source" and rebase onto the current timebase:
9965 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
9969 Generate timestamps by counting samples:
9976 @section settb, asettb
9978 Set the timebase to use for the output frames timestamps.
9979 It is mainly useful for testing timebase configuration.
9981 This filter accepts the following options:
9986 The expression which is evaluated into the output timebase.
9990 The value for @option{tb} is an arithmetic expression representing a
9991 rational. The expression can contain the constants "AVTB" (the default
9992 timebase), "intb" (the input timebase) and "sr" (the sample rate,
9993 audio only). Default value is "intb".
9995 @subsection Examples
9999 Set the timebase to 1/25:
10005 Set the timebase to 1/10:
10011 Set the timebase to 1001/1000:
10017 Set the timebase to 2*intb:
10023 Set the default timebase value:
10029 @section showspectrum
10031 Convert input audio to a video output, representing the audio frequency
10034 The filter accepts the following options:
10038 Specify the video size for the output. For the syntax of this option, check
10039 the "Video size" section in the ffmpeg-utils manual. Default value is
10043 Specify if the spectrum should slide along the window. Default value is
10047 Specify display mode.
10049 It accepts the following values:
10052 all channels are displayed in the same row
10054 all channels are displayed in separate rows
10057 Default value is @samp{combined}.
10060 Specify display color mode.
10062 It accepts the following values:
10065 each channel is displayed in a separate color
10067 each channel is is displayed using the same color scheme
10070 Default value is @samp{channel}.
10073 Specify scale used for calculating intensity color values.
10075 It accepts the following values:
10080 square root, default
10087 Default value is @samp{sqrt}.
10090 Set saturation modifier for displayed colors. Negative values provide
10091 alternative color scheme. @code{0} is no saturation at all.
10092 Saturation must be in [-10.0, 10.0] range.
10093 Default value is @code{1}.
10096 Set window function.
10098 It accepts the following values:
10101 No samples pre-processing (do not expect this to be faster)
10110 Default value is @code{hann}.
10113 The usage is very similar to the showwaves filter; see the examples in that
10116 @subsection Examples
10120 Large window with logarithmic color scaling:
10122 showspectrum=s=1280x480:scale=log
10126 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
10128 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10129 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
10135 Convert input audio to a video output, representing the samples waves.
10137 The filter accepts the following options:
10141 Specify the video size for the output. For the syntax of this option, check
10142 the "Video size" section in the ffmpeg-utils manual. Default value
10148 Available values are:
10151 Draw a point for each sample.
10154 Draw a vertical line for each sample.
10157 Default value is @code{point}.
10160 Set the number of samples which are printed on the same column. A
10161 larger value will decrease the frame rate. Must be a positive
10162 integer. This option can be set only if the value for @var{rate}
10163 is not explicitly specified.
10166 Set the (approximate) output frame rate. This is done by setting the
10167 option @var{n}. Default value is "25".
10171 @subsection Examples
10175 Output the input file audio and the corresponding video representation
10178 amovie=a.mp3,asplit[out0],showwaves[out1]
10182 Create a synthetic signal and show it with showwaves, forcing a
10183 frame rate of 30 frames per second:
10185 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
10189 @section split, asplit
10191 Split input into several identical outputs.
10193 @code{asplit} works with audio input, @code{split} with video.
10195 The filter accepts a single parameter which specifies the number of outputs. If
10196 unspecified, it defaults to 2.
10198 @subsection Examples
10202 Create two separate outputs from the same input:
10204 [in] split [out0][out1]
10208 To create 3 or more outputs, you need to specify the number of
10211 [in] asplit=3 [out0][out1][out2]
10215 Create two separate outputs from the same input, one cropped and
10218 [in] split [splitout1][splitout2];
10219 [splitout1] crop=100:100:0:0 [cropout];
10220 [splitout2] pad=200:200:100:100 [padout];
10224 Create 5 copies of the input audio with @command{ffmpeg}:
10226 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
10232 Receive commands sent through a libzmq client, and forward them to
10233 filters in the filtergraph.
10235 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
10236 must be inserted between two video filters, @code{azmq} between two
10239 To enable these filters you need to install the libzmq library and
10240 headers and configure FFmpeg with @code{--enable-libzmq}.
10242 For more information about libzmq see:
10243 @url{http://www.zeromq.org/}
10245 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
10246 receives messages sent through a network interface defined by the
10247 @option{bind_address} option.
10249 The received message must be in the form:
10251 @var{TARGET} @var{COMMAND} [@var{ARG}]
10254 @var{TARGET} specifies the target of the command, usually the name of
10255 the filter class or a specific filter instance name.
10257 @var{COMMAND} specifies the name of the command for the target filter.
10259 @var{ARG} is optional and specifies the optional argument list for the
10260 given @var{COMMAND}.
10262 Upon reception, the message is processed and the corresponding command
10263 is injected into the filtergraph. Depending on the result, the filter
10264 will send a reply to the client, adopting the format:
10266 @var{ERROR_CODE} @var{ERROR_REASON}
10270 @var{MESSAGE} is optional.
10272 @subsection Examples
10274 Look at @file{tools/zmqsend} for an example of a zmq client which can
10275 be used to send commands processed by these filters.
10277 Consider the following filtergraph generated by @command{ffplay}
10279 ffplay -dumpgraph 1 -f lavfi "
10280 color=s=100x100:c=red [l];
10281 color=s=100x100:c=blue [r];
10282 nullsrc=s=200x100, zmq [bg];
10283 [bg][l] overlay [bg+l];
10284 [bg+l][r] overlay=x=100 "
10287 To change the color of the left side of the video, the following
10288 command can be used:
10290 echo Parsed_color_0 c yellow | tools/zmqsend
10293 To change the right side:
10295 echo Parsed_color_1 c pink | tools/zmqsend
10298 @c man end MULTIMEDIA FILTERS
10300 @chapter Multimedia Sources
10301 @c man begin MULTIMEDIA SOURCES
10303 Below is a description of the currently available multimedia sources.
10307 This is the same as @ref{movie} source, except it selects an audio
10313 Read audio and/or video stream(s) from a movie container.
10315 This filter accepts the following options:
10319 The name of the resource to read (not necessarily a file but also a device or a
10320 stream accessed through some protocol).
10322 @item format_name, f
10323 Specifies the format assumed for the movie to read, and can be either
10324 the name of a container or an input device. If not specified the
10325 format is guessed from @var{movie_name} or by probing.
10327 @item seek_point, sp
10328 Specifies the seek point in seconds, the frames will be output
10329 starting from this seek point, the parameter is evaluated with
10330 @code{av_strtod} so the numerical value may be suffixed by an IS
10331 postfix. Default value is "0".
10334 Specifies the streams to read. Several streams can be specified,
10335 separated by "+". The source will then have as many outputs, in the
10336 same order. The syntax is explained in the ``Stream specifiers''
10337 section in the ffmpeg manual. Two special names, "dv" and "da" specify
10338 respectively the default (best suited) video and audio stream. Default
10339 is "dv", or "da" if the filter is called as "amovie".
10341 @item stream_index, si
10342 Specifies the index of the video stream to read. If the value is -1,
10343 the best suited video stream will be automatically selected. Default
10344 value is "-1". Deprecated. If the filter is called "amovie", it will select
10345 audio instead of video.
10348 Specifies how many times to read the stream in sequence.
10349 If the value is less than 1, the stream will be read again and again.
10350 Default value is "1".
10352 Note that when the movie is looped the source timestamps are not
10353 changed, so it will generate non monotonically increasing timestamps.
10356 This filter allows one to overlay a second video on top of main input of
10357 a filtergraph as shown in this graph:
10359 input -----------> deltapts0 --> overlay --> output
10362 movie --> scale--> deltapts1 -------+
10365 @subsection Examples
10369 Skip 3.2 seconds from the start of the avi file in.avi, and overlay it
10370 on top of the input labelled as "in":
10372 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
10373 [in] setpts=PTS-STARTPTS [main];
10374 [main][over] overlay=16:16 [out]
10378 Read from a video4linux2 device, and overlay it on top of the input
10381 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
10382 [in] setpts=PTS-STARTPTS [main];
10383 [main][over] overlay=16:16 [out]
10387 Read the first video stream and the audio stream with id 0x81 from
10388 dvd.vob; the video is connected to the pad named "video" and the audio is
10389 connected to the pad named "audio":
10391 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
10395 @c man end MULTIMEDIA SOURCES