1 @chapter Filtering Introduction
2 @c man begin FILTERING INTRODUCTION
4 Filtering in FFmpeg is enabled through the libavfilter library.
6 In libavfilter, a filter can have multiple inputs and multiple
8 To illustrate the sorts of things that are possible, we consider the
13 input --> split ---------------------> overlay --> output
16 +-----> crop --> vflip -------+
19 This filtergraph splits the input stream in two streams, sends one
20 stream through the crop filter and the vflip filter before merging it
21 back with the other stream by overlaying it on top. You can use the
22 following command to achieve this:
25 ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
28 The result will be that in output the top half of the video is mirrored
31 Filters in the same linear chain are separated by commas, and distinct
32 linear chains of filters are separated by semicolons. In our example,
33 @var{crop,vflip} are in one linear chain, @var{split} and
34 @var{overlay} are separately in another. The points where the linear
35 chains join are labelled by names enclosed in square brackets. In the
36 example, the split filter generates two outputs that are associated to
37 the labels @var{[main]} and @var{[tmp]}.
39 The stream sent to the second output of @var{split}, labelled as
40 @var{[tmp]}, is processed through the @var{crop} filter, which crops
41 away the lower half part of the video, and then vertically flipped. The
42 @var{overlay} filter takes in input the first unchanged output of the
43 split filter (which was labelled as @var{[main]}), and overlay on its
44 lower half the output generated by the @var{crop,vflip} filterchain.
46 Some filters take in input a list of parameters: they are specified
47 after the filter name and an equal sign, and are separated from each other
50 There exist so-called @var{source filters} that do not have an
51 audio/video input, and @var{sink filters} that will not have audio/video
54 @c man end FILTERING INTRODUCTION
57 @c man begin GRAPH2DOT
59 The @file{graph2dot} program included in the FFmpeg @file{tools}
60 directory can be used to parse a filtergraph description and issue a
61 corresponding textual representation in the dot language.
68 to see how to use @file{graph2dot}.
70 You can then pass the dot description to the @file{dot} program (from
71 the graphviz suite of programs) and obtain a graphical representation
74 For example the sequence of commands:
76 echo @var{GRAPH_DESCRIPTION} | \
77 tools/graph2dot -o graph.tmp && \
78 dot -Tpng graph.tmp -o graph.png && \
82 can be used to create and display an image representing the graph
83 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
84 a complete self-contained graph, with its inputs and outputs explicitly defined.
85 For example if your command line is of the form:
87 ffmpeg -i infile -vf scale=640:360 outfile
89 your @var{GRAPH_DESCRIPTION} string will need to be of the form:
91 nullsrc,scale=640:360,nullsink
93 you may also need to set the @var{nullsrc} parameters and add a @var{format}
94 filter in order to simulate a specific input file.
98 @chapter Filtergraph description
99 @c man begin FILTERGRAPH DESCRIPTION
101 A filtergraph is a directed graph of connected filters. It can contain
102 cycles, and there can be multiple links between a pair of
103 filters. Each link has one input pad on one side connecting it to one
104 filter from which it takes its input, and one output pad on the other
105 side connecting it to the one filter accepting its output.
107 Each filter in a filtergraph is an instance of a filter class
108 registered in the application, which defines the features and the
109 number of input and output pads of the filter.
111 A filter with no input pads is called a "source", a filter with no
112 output pads is called a "sink".
114 @anchor{Filtergraph syntax}
115 @section Filtergraph syntax
117 A filtergraph can be represented using a textual representation, which is
118 recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
119 options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the
120 @code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} function defined in
121 @file{libavfilter/avfilter.h}.
123 A filterchain consists of a sequence of connected filters, each one
124 connected to the previous one in the sequence. A filterchain is
125 represented by a list of ","-separated filter descriptions.
127 A filtergraph consists of a sequence of filterchains. A sequence of
128 filterchains is represented by a list of ";"-separated filterchain
131 A filter is represented by a string of the form:
132 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
134 @var{filter_name} is the name of the filter class of which the
135 described filter is an instance of, and has to be the name of one of
136 the filter classes registered in the program.
137 The name of the filter class is optionally followed by a string
140 @var{arguments} is a string which contains the parameters used to
141 initialize the filter instance. It may have one of the following forms:
145 A ':'-separated list of @var{key=value} pairs.
148 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
149 the option names in the order they are declared. E.g. the @code{fade} filter
150 declares three options in this order -- @option{type}, @option{start_frame} and
151 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
152 @var{in} is assigned to the option @option{type}, @var{0} to
153 @option{start_frame} and @var{30} to @option{nb_frames}.
156 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
157 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
158 follow the same constraints order of the previous point. The following
159 @var{key=value} pairs can be set in any preferred order.
163 If the option value itself is a list of items (e.g. the @code{format} filter
164 takes a list of pixel formats), the items in the list are usually separated by
167 The list of arguments can be quoted using the character "'" as initial
168 and ending mark, and the character '\' for escaping the characters
169 within the quoted text; otherwise the argument string is considered
170 terminated when the next special character (belonging to the set
171 "[]=;,") is encountered.
173 The name and arguments of the filter are optionally preceded and
174 followed by a list of link labels.
175 A link label allows one to name a link and associate it to a filter output
176 or input pad. The preceding labels @var{in_link_1}
177 ... @var{in_link_N}, are associated to the filter input pads,
178 the following labels @var{out_link_1} ... @var{out_link_M}, are
179 associated to the output pads.
181 When two link labels with the same name are found in the
182 filtergraph, a link between the corresponding input and output pad is
185 If an output pad is not labelled, it is linked by default to the first
186 unlabelled input pad of the next filter in the filterchain.
187 For example in the filterchain:
189 nullsrc, split[L1], [L2]overlay, nullsink
191 the split filter instance has two output pads, and the overlay filter
192 instance two input pads. The first output pad of split is labelled
193 "L1", the first input pad of overlay is labelled "L2", and the second
194 output pad of split is linked to the second input pad of overlay,
195 which are both unlabelled.
197 In a complete filterchain all the unlabelled filter input and output
198 pads must be connected. A filtergraph is considered valid if all the
199 filter input and output pads of all the filterchains are connected.
201 Libavfilter will automatically insert @ref{scale} filters where format
202 conversion is required. It is possible to specify swscale flags
203 for those automatically inserted scalers by prepending
204 @code{sws_flags=@var{flags};}
205 to the filtergraph description.
207 Follows a BNF description for the filtergraph syntax:
209 @var{NAME} ::= sequence of alphanumeric characters and '_'
210 @var{LINKLABEL} ::= "[" @var{NAME} "]"
211 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
212 @var{FILTER_ARGUMENTS} ::= sequence of chars (eventually quoted)
213 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
214 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
215 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
218 @section Notes on filtergraph escaping
220 Filtergraph description composition entails several levels of
221 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
222 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
223 information about the employed escaping procedure.
225 A first level escaping affects the content of each filter option
226 value, which may contain the special character @code{:} used to
227 separate values, or one of the escaping characters @code{\'}.
229 A second level escaping affects the whole filter description, which
230 may contain the escaping characters @code{\'} or the special
231 characters @code{[],;} used by the filtergraph description.
233 Finally, when you specify a filtergraph on a shell commandline, you
234 need to perform a third level escaping for the shell special
235 characters contained within it.
237 For example, consider the following string to be embedded in
238 the @ref{drawtext} filter description @option{text} value:
240 this is a 'string': may contain one, or more, special characters
243 This string contains the @code{'} special escaping character, and the
244 @code{:} special character, so it needs to be escaped in this way:
246 text=this is a \'string\'\: may contain one, or more, special characters
249 A second level of escaping is required when embedding the filter
250 description in a filtergraph description, in order to escape all the
251 filtergraph special characters. Thus the example above becomes:
253 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
255 (note that in addition to the @code{\'} escaping special characters,
256 also @code{,} needs to be escaped).
258 Finally an additional level of escaping is needed when writing the
259 filtergraph description in a shell command, which depends on the
260 escaping rules of the adopted shell. For example, assuming that
261 @code{\} is special and needs to be escaped with another @code{\}, the
262 previous string will finally result in:
264 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
267 @chapter Timeline editing
269 Some filters support a generic @option{enable} option. For the filters
270 supporting timeline editing, this option can be set to an expression which is
271 evaluated before sending a frame to the filter. If the evaluation is non-zero,
272 the filter will be enabled, otherwise the frame will be sent unchanged to the
273 next filter in the filtergraph.
275 The expression accepts the following values:
278 timestamp expressed in seconds, NAN if the input timestamp is unknown
281 sequential number of the input frame, starting from 0
284 the position in the file of the input frame, NAN if unknown
287 Additionally, these filters support an @option{enable} command that can be used
288 to re-define the expression.
290 Like any other filtering option, the @option{enable} option follows the same
293 For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3
294 minutes, and a @ref{curves} filter starting at 3 seconds:
296 smartblur = enable='between(t,10,3*60)',
297 curves = enable='gte(t,3)' : preset=cross_process
300 @c man end FILTERGRAPH DESCRIPTION
302 @chapter Audio Filters
303 @c man begin AUDIO FILTERS
305 When you configure your FFmpeg build, you can disable any of the
306 existing filters using @code{--disable-filters}.
307 The configure output will show the audio filters included in your
310 Below is a description of the currently available audio filters.
314 Convert the input audio format to the specified formats.
316 @emph{This filter is deprecated. Use @ref{aformat} instead.}
318 The filter accepts a string of the form:
319 "@var{sample_format}:@var{channel_layout}".
321 @var{sample_format} specifies the sample format, and can be a string or the
322 corresponding numeric value defined in @file{libavutil/samplefmt.h}. Use 'p'
323 suffix for a planar sample format.
325 @var{channel_layout} specifies the channel layout, and can be a string
326 or the corresponding number value defined in @file{libavutil/channel_layout.h}.
328 The special parameter "auto", signifies that the filter will
329 automatically select the output format depending on the output filter.
335 Convert input to float, planar, stereo:
341 Convert input to unsigned 8-bit, automatically select out channel layout:
349 Delay one or more audio channels.
351 Samples in delayed channel are filled with silence.
353 The filter accepts the following option:
357 Set list of delays in milliseconds for each channel separated by '|'.
358 At least one delay greater than 0 should be provided.
359 Unused delays will be silently ignored. If number of given delays is
360 smaller than number of channels all remaining channels will not be delayed.
367 Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave
368 the second channel (and any other channels that may be present) unchanged.
376 Apply echoing to the input audio.
378 Echoes are reflected sound and can occur naturally amongst mountains
379 (and sometimes large buildings) when talking or shouting; digital echo
380 effects emulate this behaviour and are often used to help fill out the
381 sound of a single instrument or vocal. The time difference between the
382 original signal and the reflection is the @code{delay}, and the
383 loudness of the reflected signal is the @code{decay}.
384 Multiple echoes can have different delays and decays.
386 A description of the accepted parameters follows.
390 Set input gain of reflected signal. Default is @code{0.6}.
393 Set output gain of reflected signal. Default is @code{0.3}.
396 Set list of time intervals in milliseconds between original signal and reflections
397 separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}.
398 Default is @code{1000}.
401 Set list of loudnesses of reflected signals separated by '|'.
402 Allowed range for each @code{decay} is @code{(0 - 1.0]}.
403 Default is @code{0.5}.
410 Make it sound as if there are twice as many instruments as are actually playing:
412 aecho=0.8:0.88:60:0.4
416 If delay is very short, then it sound like a (metallic) robot playing music:
422 A longer delay will sound like an open air concert in the mountains:
424 aecho=0.8:0.9:1000:0.3
428 Same as above but with one more mountain:
430 aecho=0.8:0.9:1000|1800:0.3|0.25
436 Modify an audio signal according to the specified expressions.
438 This filter accepts one or more expressions (one for each channel),
439 which are evaluated and used to modify a corresponding audio signal.
441 This filter accepts the following options:
445 Set the '|'-separated expressions list for each separate channel. If
446 the number of input channels is greater than the number of
447 expressions, the last specified expression is used for the remaining
450 @item channel_layout, c
451 Set output channel layout. If not specified, the channel layout is
452 specified by the number of expressions. If set to @samp{same}, it will
453 use by default the same input channel layout.
456 Each expression in @var{exprs} can contain the following constants and functions:
460 channel number of the current expression
463 number of the evaluated sample, starting from 0
469 time of the evaluated sample expressed in seconds
472 @item nb_out_channels
473 input and output number of channels
476 the value of input channel with number @var{CH}
479 Note: this filter is slow. For faster processing you should use a
488 aeval=val(ch)/2:c=same
492 Invert phase of the second channel:
500 Apply fade-in/out effect to input audio.
502 A description of the accepted parameters follows.
506 Specify the effect type, can be either @code{in} for fade-in, or
507 @code{out} for a fade-out effect. Default is @code{in}.
509 @item start_sample, ss
510 Specify the number of the start sample for starting to apply the fade
511 effect. Default is 0.
514 Specify the number of samples for which the fade effect has to last. At
515 the end of the fade-in effect the output audio will have the same
516 volume as the input audio, at the end of the fade-out transition
517 the output audio will be silence. Default is 44100.
520 Specify time for starting to apply the fade effect. Default is 0.
521 The accepted syntax is:
523 [-]HH[:MM[:SS[.m...]]]
526 See also the function @code{av_parse_time()}.
527 If set this option is used instead of @var{start_sample} one.
530 Specify the duration for which the fade effect has to last. Default is 0.
531 The accepted syntax is:
533 [-]HH[:MM[:SS[.m...]]]
536 See also the function @code{av_parse_time()}.
537 At the end of the fade-in effect the output audio will have the same
538 volume as the input audio, at the end of the fade-out transition
539 the output audio will be silence.
540 If set this option is used instead of @var{nb_samples} one.
543 Set curve for fade transition.
545 It accepts the following values:
548 select triangular, linear slope (default)
550 select quarter of sine wave
552 select half of sine wave
554 select exponential sine wave
558 select inverted parabola
574 Fade in first 15 seconds of audio:
580 Fade out last 25 seconds of a 900 seconds audio:
582 afade=t=out:st=875:d=25
589 Set output format constraints for the input audio. The framework will
590 negotiate the most appropriate format to minimize conversions.
592 The filter accepts the following named parameters:
596 A '|'-separated list of requested sample formats.
599 A '|'-separated list of requested sample rates.
601 @item channel_layouts
602 A '|'-separated list of requested channel layouts.
604 See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils}
605 for the required syntax.
608 If a parameter is omitted, all values are allowed.
610 For example to force the output to either unsigned 8-bit or signed 16-bit stereo:
612 aformat=sample_fmts=u8|s16:channel_layouts=stereo
617 Apply a two-pole all-pass filter with central frequency (in Hz)
618 @var{frequency}, and filter-width @var{width}.
619 An all-pass filter changes the audio's frequency to phase relationship
620 without changing its frequency to amplitude relationship.
622 The filter accepts the following options:
629 Set method to specify band-width of filter.
642 Specify the band-width of a filter in width_type units.
647 Merge two or more audio streams into a single multi-channel stream.
649 The filter accepts the following options:
654 Set the number of inputs. Default is 2.
658 If the channel layouts of the inputs are disjoint, and therefore compatible,
659 the channel layout of the output will be set accordingly and the channels
660 will be reordered as necessary. If the channel layouts of the inputs are not
661 disjoint, the output will have all the channels of the first input then all
662 the channels of the second input, in that order, and the channel layout of
663 the output will be the default value corresponding to the total number of
666 For example, if the first input is in 2.1 (FL+FR+LF) and the second input
667 is FC+BL+BR, then the output will be in 5.1, with the channels in the
668 following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
669 first input, b1 is the first channel of the second input).
671 On the other hand, if both input are in stereo, the output channels will be
672 in the default order: a1, a2, b1, b2, and the channel layout will be
673 arbitrarily set to 4.0, which may or may not be the expected value.
675 All inputs must have the same sample rate, and format.
677 If inputs do not have the same duration, the output will stop with the
684 Merge two mono files into a stereo stream:
686 amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
690 Multiple merges assuming 1 video stream and 6 audio streams in @file{input.mkv}:
692 ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv
698 Mixes multiple audio inputs into a single output.
702 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
704 will mix 3 input audio streams to a single output with the same duration as the
705 first input and a dropout transition time of 3 seconds.
707 The filter accepts the following named parameters:
711 Number of inputs. If unspecified, it defaults to 2.
714 How to determine the end-of-stream.
718 Duration of longest input. (default)
721 Duration of shortest input.
724 Duration of first input.
728 @item dropout_transition
729 Transition time, in seconds, for volume renormalization when an input
730 stream ends. The default value is 2 seconds.
736 Pass the audio source unchanged to the output.
740 Pad the end of a audio stream with silence, this can be used together with
741 -shortest to extend audio streams to the same length as the video stream.
744 Add a phasing effect to the input audio.
746 A phaser filter creates series of peaks and troughs in the frequency spectrum.
747 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
749 A description of the accepted parameters follows.
753 Set input gain. Default is 0.4.
756 Set output gain. Default is 0.74
759 Set delay in milliseconds. Default is 3.0.
762 Set decay. Default is 0.4.
765 Set modulation speed in Hz. Default is 0.5.
768 Set modulation type. Default is triangular.
770 It accepts the following values:
780 Resample the input audio to the specified parameters, using the
781 libswresample library. If none are specified then the filter will
782 automatically convert between its input and output.
784 This filter is also able to stretch/squeeze the audio data to make it match
785 the timestamps or to inject silence / cut out audio to make it match the
786 timestamps, do a combination of both or do neither.
788 The filter accepts the syntax
789 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
790 expresses a sample rate and @var{resampler_options} is a list of
791 @var{key}=@var{value} pairs, separated by ":". See the
792 ffmpeg-resampler manual for the complete list of supported options.
798 Resample the input audio to 44100Hz:
804 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
805 samples per second compensation:
811 @section asetnsamples
813 Set the number of samples per each output audio frame.
815 The last output packet may contain a different number of samples, as
816 the filter will flush all the remaining samples when the input audio
819 The filter accepts the following options:
823 @item nb_out_samples, n
824 Set the number of frames per each output audio frame. The number is
825 intended as the number of samples @emph{per each channel}.
826 Default value is 1024.
829 If set to 1, the filter will pad the last audio frame with zeroes, so
830 that the last frame will contain the same number of samples as the
831 previous ones. Default value is 1.
834 For example, to set the number of per-frame samples to 1234 and
835 disable padding for the last frame, use:
837 asetnsamples=n=1234:p=0
842 Set the sample rate without altering the PCM data.
843 This will result in a change of speed and pitch.
845 The filter accepts the following options:
849 Set the output sample rate. Default is 44100 Hz.
854 Show a line containing various information for each input audio frame.
855 The input audio is not modified.
857 The shown line contains a sequence of key/value pairs of the form
858 @var{key}:@var{value}.
860 A description of each shown parameter follows:
864 sequential number of the input frame, starting from 0
867 Presentation timestamp of the input frame, in time base units; the time base
868 depends on the filter input pad, and is usually 1/@var{sample_rate}.
871 presentation timestamp of the input frame in seconds
874 position of the frame in the input stream, -1 if this information in
875 unavailable and/or meaningless (for example in case of synthetic audio)
884 sample rate for the audio frame
887 number of samples (per channel) in the frame
890 Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio
891 the data is treated as if all the planes were concatenated.
893 @item plane_checksums
894 A list of Adler-32 checksums for each data plane.
899 Display time domain statistical information about the audio channels.
900 Statistics are calculated and displayed for each audio channel and,
901 where applicable, an overall figure is also given.
903 The filter accepts the following option:
906 Short window length in seconds, used for peak and trough RMS measurement.
907 Default is @code{0.05} (50 miliseconds). Allowed range is @code{[0.1 - 10]}.
910 A description of each shown parameter follows:
914 Mean amplitude displacement from zero.
917 Minimal sample level.
920 Maximal sample level.
924 Standard peak and RMS level measured in dBFS.
928 Peak and trough values for RMS level measured over a short window.
931 Standard ratio of peak to RMS level (note: not in dB).
934 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
935 (i.e. either @var{Min level} or @var{Max level}).
938 Number of occasions (not the number of samples) that the signal attained either
939 @var{Min level} or @var{Max level}.
944 Forward two audio streams and control the order the buffers are forwarded.
946 The filter accepts the following options:
950 Set the expression deciding which stream should be
951 forwarded next: if the result is negative, the first stream is forwarded; if
952 the result is positive or zero, the second stream is forwarded. It can use
953 the following variables:
957 number of buffers forwarded so far on each stream
959 number of samples forwarded so far on each stream
961 current timestamp of each stream
964 The default value is @code{t1-t2}, which means to always forward the stream
965 that has a smaller timestamp.
970 Stress-test @code{amerge} by randomly sending buffers on the wrong
971 input, while avoiding too much of a desynchronization:
973 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
974 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
980 Synchronize audio data with timestamps by squeezing/stretching it and/or
981 dropping samples/adding silence when needed.
983 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
985 The filter accepts the following named parameters:
989 Enable stretching/squeezing the data to make it match the timestamps. Disabled
990 by default. When disabled, time gaps are covered with silence.
993 Minimum difference between timestamps and audio data (in seconds) to trigger
994 adding/dropping samples. Default value is 0.1. If you get non-perfect sync with
995 this filter, try setting this parameter to 0.
998 Maximum compensation in samples per second. Relevant only with compensate=1.
1002 Assume the first pts should be this value. The time base is 1 / sample rate.
1003 This allows for padding/trimming at the start of stream. By default, no
1004 assumption is made about the first frame's expected pts, so no padding or
1005 trimming is done. For example, this could be set to 0 to pad the beginning with
1006 silence if an audio stream starts after the video stream or to trim any samples
1007 with a negative pts due to encoder delay.
1015 The filter accepts exactly one parameter, the audio tempo. If not
1016 specified then the filter will assume nominal 1.0 tempo. Tempo must
1017 be in the [0.5, 2.0] range.
1019 @subsection Examples
1023 Slow down audio to 80% tempo:
1029 To speed up audio to 125% tempo:
1037 Trim the input so that the output contains one continuous subpart of the input.
1039 This filter accepts the following options:
1042 Specify time of the start of the kept section, i.e. the audio sample
1043 with the timestamp @var{start} will be the first sample in the output.
1046 Specify time of the first audio sample that will be dropped, i.e. the
1047 audio sample immediately preceding the one with the timestamp @var{end} will be
1048 the last sample in the output.
1051 Same as @var{start}, except this option sets the start timestamp in samples
1055 Same as @var{end}, except this option sets the end timestamp in samples instead
1059 Specify maximum duration of the output.
1062 Number of the first sample that should be passed to output.
1065 Number of the first sample that should be dropped.
1068 @option{start}, @option{end}, @option{duration} are expressed as time
1069 duration specifications, check the "Time duration" section in the
1070 ffmpeg-utils manual.
1072 Note that the first two sets of the start/end options and the @option{duration}
1073 option look at the frame timestamp, while the _sample options simply count the
1074 samples that pass through the filter. So start/end_pts and start/end_sample will
1075 give different results when the timestamps are wrong, inexact or do not start at
1076 zero. Also note that this filter does not modify the timestamps. If you wish
1077 that the output timestamps start at zero, insert the asetpts filter after the
1080 If multiple start or end options are set, this filter tries to be greedy and
1081 keep all samples that match at least one of the specified constraints. To keep
1082 only the part that matches all the constraints at once, chain multiple atrim
1085 The defaults are such that all the input is kept. So it is possible to set e.g.
1086 just the end values to keep everything before the specified time.
1091 drop everything except the second minute of input
1093 ffmpeg -i INPUT -af atrim=60:120
1097 keep only the first 1000 samples
1099 ffmpeg -i INPUT -af atrim=end_sample=1000
1106 Apply a two-pole Butterworth band-pass filter with central
1107 frequency @var{frequency}, and (3dB-point) band-width width.
1108 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1109 instead of the default: constant 0dB peak gain.
1110 The filter roll off at 6dB per octave (20dB per decade).
1112 The filter accepts the following options:
1116 Set the filter's central frequency. Default is @code{3000}.
1119 Constant skirt gain if set to 1. Defaults to 0.
1122 Set method to specify band-width of filter.
1135 Specify the band-width of a filter in width_type units.
1140 Apply a two-pole Butterworth band-reject filter with central
1141 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1142 The filter roll off at 6dB per octave (20dB per decade).
1144 The filter accepts the following options:
1148 Set the filter's central frequency. Default is @code{3000}.
1151 Set method to specify band-width of filter.
1164 Specify the band-width of a filter in width_type units.
1169 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1170 shelving filter with a response similar to that of a standard
1171 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1173 The filter accepts the following options:
1177 Give the gain at 0 Hz. Its useful range is about -20
1178 (for a large cut) to +20 (for a large boost).
1179 Beware of clipping when using a positive gain.
1182 Set the filter's central frequency and so can be used
1183 to extend or reduce the frequency range to be boosted or cut.
1184 The default value is @code{100} Hz.
1187 Set method to specify band-width of filter.
1200 Determine how steep is the filter's shelf transition.
1205 Apply a biquad IIR filter with the given coefficients.
1206 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1207 are the numerator and denominator coefficients respectively.
1211 Remap input channels to new locations.
1213 This filter accepts the following named parameters:
1215 @item channel_layout
1216 Channel layout of the output stream.
1219 Map channels from input to output. The argument is a '|'-separated list of
1220 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1221 @var{in_channel} form. @var{in_channel} can be either the name of the input
1222 channel (e.g. FL for front left) or its index in the input channel layout.
1223 @var{out_channel} is the name of the output channel or its index in the output
1224 channel layout. If @var{out_channel} is not given then it is implicitly an
1225 index, starting with zero and increasing by one for each mapping.
1228 If no mapping is present, the filter will implicitly map input channels to
1229 output channels preserving index.
1231 For example, assuming a 5.1+downmix input MOV file
1233 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1235 will create an output WAV file tagged as stereo from the downmix channels of
1238 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1240 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1243 @section channelsplit
1245 Split each channel in input audio stream into a separate output stream.
1247 This filter accepts the following named parameters:
1249 @item channel_layout
1250 Channel layout of the input stream. Default is "stereo".
1253 For example, assuming a stereo input MP3 file
1255 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1257 will create an output Matroska file with two audio streams, one containing only
1258 the left channel and the other the right channel.
1260 To split a 5.1 WAV file into per-channel files
1262 ffmpeg -i in.wav -filter_complex
1263 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1264 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1265 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1270 Compress or expand audio dynamic range.
1272 A description of the accepted options follows.
1278 Set list of times in seconds for each channel over which the instantaneous level
1279 of the input signal is averaged to determine its volume. @var{attacks} refers to
1280 increase of volume and @var{decays} refers to decrease of volume. For most
1281 situations, the attack time (response to the audio getting louder) should be
1282 shorter than the decay time because the human ear is more sensitive to sudden
1283 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1284 a typical value for decay is 0.8 seconds.
1287 Set list of points for the transfer function, specified in dB relative to the
1288 maximum possible signal amplitude. Each key points list must be defined using
1289 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1290 @code{x0/y0 x1/y1 x2/y2 ....}
1292 The input values must be in strictly increasing order but the transfer function
1293 does not have to be monotonically rising. The point @code{0/0} is assumed but
1294 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1295 function are @code{-70/-70|-60/-20}.
1298 Set the curve radius in dB for all joints. Defaults to 0.01.
1301 Set additional gain in dB to be applied at all points on the transfer function.
1302 This allows easy adjustment of the overall gain. Defaults to 0.
1305 Set initial volume in dB to be assumed for each channel when filtering starts.
1306 This permits the user to supply a nominal level initially, so that, for
1307 example, a very large gain is not applied to initial signal levels before the
1308 companding has begun to operate. A typical value for audio which is initially
1309 quiet is -90 dB. Defaults to 0.
1312 Set delay in seconds. The input audio is analyzed immediately, but audio is
1313 delayed before being fed to the volume adjuster. Specifying a delay
1314 approximately equal to the attack/decay times allows the filter to effectively
1315 operate in predictive rather than reactive mode. Defaults to 0.
1319 @subsection Examples
1323 Make music with both quiet and loud passages suitable for listening in a noisy
1326 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1330 Noise gate for when the noise is at a lower level than the signal:
1332 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1336 Here is another noise gate, this time for when the noise is at a higher level
1337 than the signal (making it, in some ways, similar to squelch):
1339 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1345 Make audio easier to listen to on headphones.
1347 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1348 so that when listened to on headphones the stereo image is moved from
1349 inside your head (standard for headphones) to outside and in front of
1350 the listener (standard for speakers).
1356 Apply a two-pole peaking equalisation (EQ) filter. With this
1357 filter, the signal-level at and around a selected frequency can
1358 be increased or decreased, whilst (unlike bandpass and bandreject
1359 filters) that at all other frequencies is unchanged.
1361 In order to produce complex equalisation curves, this filter can
1362 be given several times, each with a different central frequency.
1364 The filter accepts the following options:
1368 Set the filter's central frequency in Hz.
1371 Set method to specify band-width of filter.
1384 Specify the band-width of a filter in width_type units.
1387 Set the required gain or attenuation in dB.
1388 Beware of clipping when using a positive gain.
1391 @subsection Examples
1394 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1396 equalizer=f=1000:width_type=h:width=200:g=-10
1400 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1402 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1408 Apply a high-pass filter with 3dB point frequency.
1409 The filter can be either single-pole, or double-pole (the default).
1410 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1412 The filter accepts the following options:
1416 Set frequency in Hz. Default is 3000.
1419 Set number of poles. Default is 2.
1422 Set method to specify band-width of filter.
1435 Specify the band-width of a filter in width_type units.
1436 Applies only to double-pole filter.
1437 The default is 0.707q and gives a Butterworth response.
1442 Join multiple input streams into one multi-channel stream.
1444 The filter accepts the following named parameters:
1448 Number of input streams. Defaults to 2.
1450 @item channel_layout
1451 Desired output channel layout. Defaults to stereo.
1454 Map channels from inputs to output. The argument is a '|'-separated list of
1455 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1456 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1457 can be either the name of the input channel (e.g. FL for front left) or its
1458 index in the specified input stream. @var{out_channel} is the name of the output
1462 The filter will attempt to guess the mappings when those are not specified
1463 explicitly. It does so by first trying to find an unused matching input channel
1464 and if that fails it picks the first unused input channel.
1466 E.g. to join 3 inputs (with properly set channel layouts)
1468 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1471 To build a 5.1 output from 6 single-channel streams:
1473 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1474 'join=inputs=6:channel_layout=5.1:map=0.0-FL|1.0-FR|2.0-FC|3.0-SL|4.0-SR|5.0-LFE'
1480 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1482 To enable compilation of this filter you need to configure FFmpeg with
1483 @code{--enable-ladspa}.
1487 Specifies the name of LADSPA plugin library to load. If the environment
1488 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1489 each one of the directories specified by the colon separated list in
1490 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1491 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1492 @file{/usr/lib/ladspa/}.
1495 Specifies the plugin within the library. Some libraries contain only
1496 one plugin, but others contain many of them. If this is not set filter
1497 will list all available plugins within the specified library.
1500 Set the '|' separated list of controls which are zero or more floating point
1501 values that determine the behavior of the loaded plugin (for example delay,
1503 Controls need to be defined using the following syntax:
1504 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1505 @var{valuei} is the value set on the @var{i}-th control.
1506 If @option{controls} is set to @code{help}, all available controls and
1507 their valid ranges are printed.
1509 @item sample_rate, s
1510 Specify the sample rate, default to 44100. Only used if plugin have
1514 Set the number of samples per channel per each output frame, default
1515 is 1024. Only used if plugin have zero inputs.
1518 Set the minimum duration of the sourced audio. See the function
1519 @code{av_parse_time()} for the accepted format, also check the "Time duration"
1520 section in the ffmpeg-utils manual.
1521 Note that the resulting duration may be greater than the specified duration,
1522 as the generated audio is always cut at the end of a complete frame.
1523 If not specified, or the expressed duration is negative, the audio is
1524 supposed to be generated forever.
1525 Only used if plugin have zero inputs.
1529 @subsection Examples
1533 List all available plugins within amp (LADSPA example plugin) library:
1539 List all available controls and their valid ranges for @code{vcf_notch}
1540 plugin from @code{VCF} library:
1542 ladspa=f=vcf:p=vcf_notch:c=help
1546 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1549 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1553 Add reverberation to the audio using TAP-plugins
1554 (Tom's Audio Processing plugins):
1556 ladspa=file=tap_reverb:tap_reverb
1560 Generate white noise, with 0.2 amplitude:
1562 ladspa=file=cmt:noise_source_white:c=c0=.2
1566 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1567 @code{C* Audio Plugin Suite} (CAPS) library:
1569 ladspa=file=caps:Click:c=c1=20'
1573 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1575 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1579 @subsection Commands
1581 This filter supports the following commands:
1584 Modify the @var{N}-th control value.
1586 If the specified value is not valid, it is ignored and prior one is kept.
1591 Apply a low-pass filter with 3dB point frequency.
1592 The filter can be either single-pole or double-pole (the default).
1593 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1595 The filter accepts the following options:
1599 Set frequency in Hz. Default is 500.
1602 Set number of poles. Default is 2.
1605 Set method to specify band-width of filter.
1618 Specify the band-width of a filter in width_type units.
1619 Applies only to double-pole filter.
1620 The default is 0.707q and gives a Butterworth response.
1625 Mix channels with specific gain levels. The filter accepts the output
1626 channel layout followed by a set of channels definitions.
1628 This filter is also designed to remap efficiently the channels of an audio
1631 The filter accepts parameters of the form:
1632 "@var{l}:@var{outdef}:@var{outdef}:..."
1636 output channel layout or number of channels
1639 output channel specification, of the form:
1640 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1643 output channel to define, either a channel name (FL, FR, etc.) or a channel
1644 number (c0, c1, etc.)
1647 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1650 input channel to use, see out_name for details; it is not possible to mix
1651 named and numbered input channels
1654 If the `=' in a channel specification is replaced by `<', then the gains for
1655 that specification will be renormalized so that the total is 1, thus
1656 avoiding clipping noise.
1658 @subsection Mixing examples
1660 For example, if you want to down-mix from stereo to mono, but with a bigger
1661 factor for the left channel:
1663 pan=1:c0=0.9*c0+0.1*c1
1666 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1667 7-channels surround:
1669 pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1672 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1673 that should be preferred (see "-ac" option) unless you have very specific
1676 @subsection Remapping examples
1678 The channel remapping will be effective if, and only if:
1681 @item gain coefficients are zeroes or ones,
1682 @item only one input per channel output,
1685 If all these conditions are satisfied, the filter will notify the user ("Pure
1686 channel mapping detected"), and use an optimized and lossless method to do the
1689 For example, if you have a 5.1 source and want a stereo audio stream by
1690 dropping the extra channels:
1692 pan="stereo: c0=FL : c1=FR"
1695 Given the same source, you can also switch front left and front right channels
1696 and keep the input channel layout:
1698 pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
1701 If the input is a stereo audio stream, you can mute the front left channel (and
1702 still keep the stereo channel layout) with:
1707 Still with a stereo audio stream input, you can copy the right channel in both
1708 front left and right:
1710 pan="stereo: c0=FR : c1=FR"
1715 ReplayGain scanner filter. This filter takes an audio stream as an input and
1716 outputs it unchanged.
1717 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1721 Convert the audio sample format, sample rate and channel layout. This filter is
1722 not meant to be used directly.
1724 @section silencedetect
1726 Detect silence in an audio stream.
1728 This filter logs a message when it detects that the input audio volume is less
1729 or equal to a noise tolerance value for a duration greater or equal to the
1730 minimum detected noise duration.
1732 The printed times and duration are expressed in seconds.
1734 The filter accepts the following options:
1738 Set silence duration until notification (default is 2 seconds).
1741 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1742 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1745 @subsection Examples
1749 Detect 5 seconds of silence with -50dB noise tolerance:
1751 silencedetect=n=-50dB:d=5
1755 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1756 tolerance in @file{silence.mp3}:
1758 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1764 Boost or cut treble (upper) frequencies of the audio using a two-pole
1765 shelving filter with a response similar to that of a standard
1766 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1768 The filter accepts the following options:
1772 Give the gain at whichever is the lower of ~22 kHz and the
1773 Nyquist frequency. Its useful range is about -20 (for a large cut)
1774 to +20 (for a large boost). Beware of clipping when using a positive gain.
1777 Set the filter's central frequency and so can be used
1778 to extend or reduce the frequency range to be boosted or cut.
1779 The default value is @code{3000} Hz.
1782 Set method to specify band-width of filter.
1795 Determine how steep is the filter's shelf transition.
1800 Adjust the input audio volume.
1802 The filter accepts the following options:
1807 Set audio volume expression.
1809 Output values are clipped to the maximum value.
1811 The output audio volume is given by the relation:
1813 @var{output_volume} = @var{volume} * @var{input_volume}
1816 Default value for @var{volume} is "1.0".
1819 Set the mathematical precision.
1821 This determines which input sample formats will be allowed, which affects the
1822 precision of the volume scaling.
1826 8-bit fixed-point; limits input sample format to U8, S16, and S32.
1828 32-bit floating-point; limits input sample format to FLT. (default)
1830 64-bit floating-point; limits input sample format to DBL.
1834 Behaviour on encountering ReplayGain side data in input frames.
1838 Remove ReplayGain side data, ignoring its contents (the default).
1841 Ignore ReplayGain side data, but leave it in the frame.
1844 Prefer track gain, if present.
1847 Prefer album gain, if present.
1851 Set when the volume expression is evaluated.
1853 It accepts the following values:
1856 only evaluate expression once during the filter initialization, or
1857 when the @samp{volume} command is sent
1860 evaluate expression for each incoming frame
1863 Default value is @samp{once}.
1866 The volume expression can contain the following parameters.
1870 frame number (starting at zero)
1873 @item nb_consumed_samples
1874 number of samples consumed by the filter
1876 number of samples in the current frame
1878 original frame position in the file
1884 PTS at start of stream
1886 time at start of stream
1892 last set volume value
1895 Note that when @option{eval} is set to @samp{once} only the
1896 @var{sample_rate} and @var{tb} variables are available, all other
1897 variables will evaluate to NAN.
1899 @subsection Commands
1901 This filter supports the following commands:
1904 Modify the volume expression.
1905 The command accepts the same syntax of the corresponding option.
1907 If the specified expression is not valid, it is kept at its current
1911 @subsection Examples
1915 Halve the input audio volume:
1919 volume=volume=-6.0206dB
1922 In all the above example the named key for @option{volume} can be
1923 omitted, for example like in:
1929 Increase input audio power by 6 decibels using fixed-point precision:
1931 volume=volume=6dB:precision=fixed
1935 Fade volume after time 10 with an annihilation period of 5 seconds:
1937 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
1941 @section volumedetect
1943 Detect the volume of the input video.
1945 The filter has no parameters. The input is not modified. Statistics about
1946 the volume will be printed in the log when the input stream end is reached.
1948 In particular it will show the mean volume (root mean square), maximum
1949 volume (on a per-sample basis), and the beginning of a histogram of the
1950 registered volume values (from the maximum value to a cumulated 1/1000 of
1953 All volumes are in decibels relative to the maximum PCM value.
1955 @subsection Examples
1957 Here is an excerpt of the output:
1959 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
1960 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
1961 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
1962 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
1963 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
1964 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
1965 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
1966 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
1967 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
1973 The mean square energy is approximately -27 dB, or 10^-2.7.
1975 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
1977 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
1980 In other words, raising the volume by +4 dB does not cause any clipping,
1981 raising it by +5 dB causes clipping for 6 samples, etc.
1983 @c man end AUDIO FILTERS
1985 @chapter Audio Sources
1986 @c man begin AUDIO SOURCES
1988 Below is a description of the currently available audio sources.
1992 Buffer audio frames, and make them available to the filter chain.
1994 This source is mainly intended for a programmatic use, in particular
1995 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
1997 It accepts the following named parameters:
2002 Timebase which will be used for timestamps of submitted frames. It must be
2003 either a floating-point number or in @var{numerator}/@var{denominator} form.
2006 The sample rate of the incoming audio buffers.
2009 The sample format of the incoming audio buffers.
2010 Either a sample format name or its corresponging integer representation from
2011 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2013 @item channel_layout
2014 The channel layout of the incoming audio buffers.
2015 Either a channel layout name from channel_layout_map in
2016 @file{libavutil/channel_layout.c} or its corresponding integer representation
2017 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2020 The number of channels of the incoming audio buffers.
2021 If both @var{channels} and @var{channel_layout} are specified, then they
2026 @subsection Examples
2029 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2032 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2033 Since the sample format with name "s16p" corresponds to the number
2034 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2037 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2042 Generate an audio signal specified by an expression.
2044 This source accepts in input one or more expressions (one for each
2045 channel), which are evaluated and used to generate a corresponding
2048 This source accepts the following options:
2052 Set the '|'-separated expressions list for each separate channel. In case the
2053 @option{channel_layout} option is not specified, the selected channel layout
2054 depends on the number of provided expressions. Otherwise the last
2055 specified expression is applied to the remaining output channels.
2057 @item channel_layout, c
2058 Set the channel layout. The number of channels in the specified layout
2059 must be equal to the number of specified expressions.
2062 Set the minimum duration of the sourced audio. See the function
2063 @code{av_parse_time()} for the accepted format.
2064 Note that the resulting duration may be greater than the specified
2065 duration, as the generated audio is always cut at the end of a
2068 If not specified, or the expressed duration is negative, the audio is
2069 supposed to be generated forever.
2072 Set the number of samples per channel per each output frame,
2075 @item sample_rate, s
2076 Specify the sample rate, default to 44100.
2079 Each expression in @var{exprs} can contain the following constants:
2083 number of the evaluated sample, starting from 0
2086 time of the evaluated sample expressed in seconds, starting from 0
2093 @subsection Examples
2103 Generate a sin signal with frequency of 440 Hz, set sample rate to
2106 aevalsrc="sin(440*2*PI*t):s=8000"
2110 Generate a two channels signal, specify the channel layout (Front
2111 Center + Back Center) explicitly:
2113 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2117 Generate white noise:
2119 aevalsrc="-2+random(0)"
2123 Generate an amplitude modulated signal:
2125 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2129 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2131 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2138 Null audio source, return unprocessed audio frames. It is mainly useful
2139 as a template and to be employed in analysis / debugging tools, or as
2140 the source for filters which ignore the input data (for example the sox
2143 This source accepts the following options:
2147 @item channel_layout, cl
2149 Specify the channel layout, and can be either an integer or a string
2150 representing a channel layout. The default value of @var{channel_layout}
2153 Check the channel_layout_map definition in
2154 @file{libavutil/channel_layout.c} for the mapping between strings and
2155 channel layout values.
2157 @item sample_rate, r
2158 Specify the sample rate, and defaults to 44100.
2161 Set the number of samples per requested frames.
2165 @subsection Examples
2169 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2171 anullsrc=r=48000:cl=4
2175 Do the same operation with a more obvious syntax:
2177 anullsrc=r=48000:cl=mono
2181 All the parameters need to be explicitly defined.
2185 Synthesize a voice utterance using the libflite library.
2187 To enable compilation of this filter you need to configure FFmpeg with
2188 @code{--enable-libflite}.
2190 Note that the flite library is not thread-safe.
2192 The filter accepts the following options:
2197 If set to 1, list the names of the available voices and exit
2198 immediately. Default value is 0.
2201 Set the maximum number of samples per frame. Default value is 512.
2204 Set the filename containing the text to speak.
2207 Set the text to speak.
2210 Set the voice to use for the speech synthesis. Default value is
2211 @code{kal}. See also the @var{list_voices} option.
2214 @subsection Examples
2218 Read from file @file{speech.txt}, and synthetize the text using the
2219 standard flite voice:
2221 flite=textfile=speech.txt
2225 Read the specified text selecting the @code{slt} voice:
2227 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2231 Input text to ffmpeg:
2233 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2237 Make @file{ffplay} speak the specified text, using @code{flite} and
2238 the @code{lavfi} device:
2240 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2244 For more information about libflite, check:
2245 @url{http://www.speech.cs.cmu.edu/flite/}
2249 Generate an audio signal made of a sine wave with amplitude 1/8.
2251 The audio signal is bit-exact.
2253 The filter accepts the following options:
2258 Set the carrier frequency. Default is 440 Hz.
2260 @item beep_factor, b
2261 Enable a periodic beep every second with frequency @var{beep_factor} times
2262 the carrier frequency. Default is 0, meaning the beep is disabled.
2264 @item sample_rate, r
2265 Specify the sample rate, default is 44100.
2268 Specify the duration of the generated audio stream.
2270 @item samples_per_frame
2271 Set the number of samples per output frame, default is 1024.
2274 @subsection Examples
2279 Generate a simple 440 Hz sine wave:
2285 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2289 sine=frequency=220:beep_factor=4:duration=5
2294 @c man end AUDIO SOURCES
2296 @chapter Audio Sinks
2297 @c man begin AUDIO SINKS
2299 Below is a description of the currently available audio sinks.
2301 @section abuffersink
2303 Buffer audio frames, and make them available to the end of filter chain.
2305 This sink is mainly intended for programmatic use, in particular
2306 through the interface defined in @file{libavfilter/buffersink.h}
2307 or the options system.
2309 It accepts a pointer to an AVABufferSinkContext structure, which
2310 defines the incoming buffers' formats, to be passed as the opaque
2311 parameter to @code{avfilter_init_filter} for initialization.
2315 Null audio sink, do absolutely nothing with the input audio. It is
2316 mainly useful as a template and to be employed in analysis / debugging
2319 @c man end AUDIO SINKS
2321 @chapter Video Filters
2322 @c man begin VIDEO FILTERS
2324 When you configure your FFmpeg build, you can disable any of the
2325 existing filters using @code{--disable-filters}.
2326 The configure output will show the video filters included in your
2329 Below is a description of the currently available video filters.
2331 @section alphaextract
2333 Extract the alpha component from the input as a grayscale video. This
2334 is especially useful with the @var{alphamerge} filter.
2338 Add or replace the alpha component of the primary input with the
2339 grayscale value of a second input. This is intended for use with
2340 @var{alphaextract} to allow the transmission or storage of frame
2341 sequences that have alpha in a format that doesn't support an alpha
2344 For example, to reconstruct full frames from a normal YUV-encoded video
2345 and a separate video created with @var{alphaextract}, you might use:
2347 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2350 Since this filter is designed for reconstruction, it operates on frame
2351 sequences without considering timestamps, and terminates when either
2352 input reaches end of stream. This will cause problems if your encoding
2353 pipeline drops frames. If you're trying to apply an image as an
2354 overlay to a video stream, consider the @var{overlay} filter instead.
2358 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2359 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2360 Substation Alpha) subtitles files.
2364 Compute the bounding box for the non-black pixels in the input frame
2367 This filter computes the bounding box containing all the pixels with a
2368 luminance value greater than the minimum allowed value.
2369 The parameters describing the bounding box are printed on the filter
2372 The filter accepts the following option:
2376 Set the minimal luminance value. Default is @code{16}.
2379 @section blackdetect
2381 Detect video intervals that are (almost) completely black. Can be
2382 useful to detect chapter transitions, commercials, or invalid
2383 recordings. Output lines contains the time for the start, end and
2384 duration of the detected black interval expressed in seconds.
2386 In order to display the output lines, you need to set the loglevel at
2387 least to the AV_LOG_INFO value.
2389 The filter accepts the following options:
2392 @item black_min_duration, d
2393 Set the minimum detected black duration expressed in seconds. It must
2394 be a non-negative floating point number.
2396 Default value is 2.0.
2398 @item picture_black_ratio_th, pic_th
2399 Set the threshold for considering a picture "black".
2400 Express the minimum value for the ratio:
2402 @var{nb_black_pixels} / @var{nb_pixels}
2405 for which a picture is considered black.
2406 Default value is 0.98.
2408 @item pixel_black_th, pix_th
2409 Set the threshold for considering a pixel "black".
2411 The threshold expresses the maximum pixel luminance value for which a
2412 pixel is considered "black". The provided value is scaled according to
2413 the following equation:
2415 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2418 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2419 the input video format, the range is [0-255] for YUV full-range
2420 formats and [16-235] for YUV non full-range formats.
2422 Default value is 0.10.
2425 The following example sets the maximum pixel threshold to the minimum
2426 value, and detects only black intervals of 2 or more seconds:
2428 blackdetect=d=2:pix_th=0.00
2433 Detect frames that are (almost) completely black. Can be useful to
2434 detect chapter transitions or commercials. Output lines consist of
2435 the frame number of the detected frame, the percentage of blackness,
2436 the position in the file if known or -1 and the timestamp in seconds.
2438 In order to display the output lines, you need to set the loglevel at
2439 least to the AV_LOG_INFO value.
2441 The filter accepts the following options:
2446 Set the percentage of the pixels that have to be below the threshold, defaults
2449 @item threshold, thresh
2450 Set the threshold below which a pixel value is considered black, defaults to
2457 Blend two video frames into each other.
2459 It takes two input streams and outputs one stream, the first input is the
2460 "top" layer and second input is "bottom" layer.
2461 Output terminates when shortest input terminates.
2463 A description of the accepted options follows.
2471 Set blend mode for specific pixel component or all pixel components in case
2472 of @var{all_mode}. Default value is @code{normal}.
2474 Available values for component modes are:
2507 Set blend opacity for specific pixel component or all pixel components in case
2508 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2515 Set blend expression for specific pixel component or all pixel components in case
2516 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2518 The expressions can use the following variables:
2522 The sequential number of the filtered frame, starting from @code{0}.
2526 the coordinates of the current sample
2530 the width and height of currently filtered plane
2534 Width and height scale depending on the currently filtered plane. It is the
2535 ratio between the corresponding luma plane number of pixels and the current
2536 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2537 @code{0.5,0.5} for chroma planes.
2540 Time of the current frame, expressed in seconds.
2543 Value of pixel component at current location for first video frame (top layer).
2546 Value of pixel component at current location for second video frame (bottom layer).
2550 Force termination when the shortest input terminates. Default is @code{0}.
2552 Continue applying the last bottom frame after the end of the stream. A value of
2553 @code{0} disable the filter after the last frame of the bottom layer is reached.
2554 Default is @code{1}.
2557 @subsection Examples
2561 Apply transition from bottom layer to top layer in first 10 seconds:
2563 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2567 Apply 1x1 checkerboard effect:
2569 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2573 Apply uncover left effect:
2575 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2579 Apply uncover down effect:
2581 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2585 Apply uncover up-left effect:
2587 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2593 Apply boxblur algorithm to the input video.
2595 The filter accepts the following options:
2599 @item luma_radius, lr
2600 @item luma_power, lp
2601 @item chroma_radius, cr
2602 @item chroma_power, cp
2603 @item alpha_radius, ar
2604 @item alpha_power, ap
2608 A description of the accepted options follows.
2611 @item luma_radius, lr
2612 @item chroma_radius, cr
2613 @item alpha_radius, ar
2614 Set an expression for the box radius in pixels used for blurring the
2615 corresponding input plane.
2617 The radius value must be a non-negative number, and must not be
2618 greater than the value of the expression @code{min(w,h)/2} for the
2619 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2622 Default value for @option{luma_radius} is "2". If not specified,
2623 @option{chroma_radius} and @option{alpha_radius} default to the
2624 corresponding value set for @option{luma_radius}.
2626 The expressions can contain the following constants:
2630 the input width and height in pixels
2634 the input chroma image width and height in pixels
2638 horizontal and vertical chroma subsample values. For example for the
2639 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2642 @item luma_power, lp
2643 @item chroma_power, cp
2644 @item alpha_power, ap
2645 Specify how many times the boxblur filter is applied to the
2646 corresponding plane.
2648 Default value for @option{luma_power} is 2. If not specified,
2649 @option{chroma_power} and @option{alpha_power} default to the
2650 corresponding value set for @option{luma_power}.
2652 A value of 0 will disable the effect.
2655 @subsection Examples
2659 Apply a boxblur filter with luma, chroma, and alpha radius
2662 boxblur=luma_radius=2:luma_power=1
2667 Set luma radius to 2, alpha and chroma radius to 0:
2669 boxblur=2:1:cr=0:ar=0
2673 Set luma and chroma radius to a fraction of the video dimension:
2675 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2679 @section colorbalance
2680 Modify intensity of primary colors (red, green and blue) of input frames.
2682 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2683 regions for the red-cyan, green-magenta or blue-yellow balance.
2685 A positive adjustment value shifts the balance towards the primary color, a negative
2686 value towards the complementary color.
2688 The filter accepts the following options:
2694 Adjust red, green and blue shadows (darkest pixels).
2699 Adjust red, green and blue midtones (medium pixels).
2704 Adjust red, green and blue highlights (brightest pixels).
2706 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2709 @subsection Examples
2713 Add red color cast to shadows:
2719 @section colorchannelmixer
2721 Adjust video input frames by re-mixing color channels.
2723 This filter modifies a color channel by adding the values associated to
2724 the other channels of the same pixels. For example if the value to
2725 modify is red, the output value will be:
2727 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2730 The filter accepts the following options:
2737 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2738 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2744 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2745 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2751 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2752 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2758 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2759 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2761 Allowed ranges for options are @code{[-2.0, 2.0]}.
2764 @subsection Examples
2768 Convert source to grayscale:
2770 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2773 Simulate sepia tones:
2775 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
2779 @section colormatrix
2781 Convert color matrix.
2783 The filter accepts the following options:
2788 Specify the source and destination color matrix. Both values must be
2791 The accepted values are:
2807 For example to convert from BT.601 to SMPTE-240M, use the command:
2809 colormatrix=bt601:smpte240m
2814 Copy the input source unchanged to the output. Mainly useful for
2819 Crop the input video to given dimensions.
2821 The filter accepts the following options:
2825 Width of the output video. It defaults to @code{iw}.
2826 This expression is evaluated only once during the filter
2830 Height of the output video. It defaults to @code{ih}.
2831 This expression is evaluated only once during the filter
2835 Horizontal position, in the input video, of the left edge of the output video.
2836 It defaults to @code{(in_w-out_w)/2}.
2837 This expression is evaluated per-frame.
2840 Vertical position, in the input video, of the top edge of the output video.
2841 It defaults to @code{(in_h-out_h)/2}.
2842 This expression is evaluated per-frame.
2845 If set to 1 will force the output display aspect ratio
2846 to be the same of the input, by changing the output sample aspect
2847 ratio. It defaults to 0.
2850 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
2851 expressions containing the following constants:
2856 the computed values for @var{x} and @var{y}. They are evaluated for
2861 the input width and height
2865 same as @var{in_w} and @var{in_h}
2869 the output (cropped) width and height
2873 same as @var{out_w} and @var{out_h}
2876 same as @var{iw} / @var{ih}
2879 input sample aspect ratio
2882 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
2886 horizontal and vertical chroma subsample values. For example for the
2887 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2890 the number of input frame, starting from 0
2893 the position in the file of the input frame, NAN if unknown
2896 timestamp expressed in seconds, NAN if the input timestamp is unknown
2900 The expression for @var{out_w} may depend on the value of @var{out_h},
2901 and the expression for @var{out_h} may depend on @var{out_w}, but they
2902 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
2903 evaluated after @var{out_w} and @var{out_h}.
2905 The @var{x} and @var{y} parameters specify the expressions for the
2906 position of the top-left corner of the output (non-cropped) area. They
2907 are evaluated for each frame. If the evaluated value is not valid, it
2908 is approximated to the nearest valid value.
2910 The expression for @var{x} may depend on @var{y}, and the expression
2911 for @var{y} may depend on @var{x}.
2913 @subsection Examples
2917 Crop area with size 100x100 at position (12,34).
2922 Using named options, the example above becomes:
2924 crop=w=100:h=100:x=12:y=34
2928 Crop the central input area with size 100x100:
2934 Crop the central input area with size 2/3 of the input video:
2936 crop=2/3*in_w:2/3*in_h
2940 Crop the input video central square:
2947 Delimit the rectangle with the top-left corner placed at position
2948 100:100 and the right-bottom corner corresponding to the right-bottom
2949 corner of the input image:
2951 crop=in_w-100:in_h-100:100:100
2955 Crop 10 pixels from the left and right borders, and 20 pixels from
2956 the top and bottom borders
2958 crop=in_w-2*10:in_h-2*20
2962 Keep only the bottom right quarter of the input image:
2964 crop=in_w/2:in_h/2:in_w/2:in_h/2
2968 Crop height for getting Greek harmony:
2970 crop=in_w:1/PHI*in_w
2974 Appply trembling effect:
2976 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)
2980 Apply erratic camera effect depending on timestamp:
2982 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)"
2986 Set x depending on the value of y:
2988 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
2994 Auto-detect crop size.
2996 Calculate necessary cropping parameters and prints the recommended
2997 parameters through the logging system. The detected dimensions
2998 correspond to the non-black area of the input video.
3000 The filter accepts the following options:
3005 Set higher black value threshold, which can be optionally specified
3006 from nothing (0) to everything (255). An intensity value greater
3007 to the set value is considered non-black. Default value is 24.
3010 Set the value for which the width/height should be divisible by. The
3011 offset is automatically adjusted to center the video. Use 2 to get
3012 only even dimensions (needed for 4:2:2 video). 16 is best when
3013 encoding to most video codecs. Default value is 16.
3015 @item reset_count, reset
3016 Set the counter that determines after how many frames cropdetect will
3017 reset the previously detected largest video area and start over to
3018 detect the current optimal crop area. Default value is 0.
3020 This can be useful when channel logos distort the video area. 0
3021 indicates never reset and return the largest area encountered during
3028 Apply color adjustments using curves.
3030 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3031 component (red, green and blue) has its values defined by @var{N} key points
3032 tied from each other using a smooth curve. The x-axis represents the pixel
3033 values from the input frame, and the y-axis the new pixel values to be set for
3036 By default, a component curve is defined by the two points @var{(0;0)} and
3037 @var{(1;1)}. This creates a straight line where each original pixel value is
3038 "adjusted" to its own value, which means no change to the image.
3040 The filter allows you to redefine these two points and add some more. A new
3041 curve (using a natural cubic spline interpolation) will be define to pass
3042 smoothly through all these new coordinates. The new defined points needs to be
3043 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3044 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3045 the vector spaces, the values will be clipped accordingly.
3047 If there is no key point defined in @code{x=0}, the filter will automatically
3048 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3049 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3051 The filter accepts the following options:
3055 Select one of the available color presets. This option can be used in addition
3056 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3057 options takes priority on the preset values.
3058 Available presets are:
3061 @item color_negative
3064 @item increase_contrast
3066 @item linear_contrast
3067 @item medium_contrast
3069 @item strong_contrast
3072 Default is @code{none}.
3074 Set the master key points. These points will define a second pass mapping. It
3075 is sometimes called a "luminance" or "value" mapping. It can be used with
3076 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3077 post-processing LUT.
3079 Set the key points for the red component.
3081 Set the key points for the green component.
3083 Set the key points for the blue component.
3085 Set the key points for all components (not including master).
3086 Can be used in addition to the other key points component
3087 options. In this case, the unset component(s) will fallback on this
3088 @option{all} setting.
3090 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3093 To avoid some filtergraph syntax conflicts, each key points list need to be
3094 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3096 @subsection Examples
3100 Increase slightly the middle level of blue:
3102 curves=blue='0.5/0.58'
3108 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3110 Here we obtain the following coordinates for each components:
3113 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3115 @code{(0;0) (0.50;0.48) (1;1)}
3117 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3121 The previous example can also be achieved with the associated built-in preset:
3123 curves=preset=vintage
3133 Use a Photoshop preset and redefine the points of the green component:
3135 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3141 Denoise frames using 2D DCT (frequency domain filtering).
3143 This filter is not designed for real time and can be extremely slow.
3145 The filter accepts the following options:
3149 Set the noise sigma constant.
3151 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3152 coefficient (absolute value) below this threshold with be dropped.
3154 If you need a more advanced filtering, see @option{expr}.
3156 Default is @code{0}.
3159 Set number overlapping pixels for each block. Each block is of size
3160 @code{16x16}. Since the filter can be slow, you may want to reduce this value,
3161 at the cost of a less effective filter and the risk of various artefacts.
3163 If the overlapping value doesn't allow to process the whole input width or
3164 height, a warning will be displayed and according borders won't be denoised.
3166 Default value is @code{15}.
3169 Set the coefficient factor expression.
3171 For each coefficient of a DCT block, this expression will be evaluated as a
3172 multiplier value for the coefficient.
3174 If this is option is set, the @option{sigma} option will be ignored.
3176 The absolute value of the coefficient can be accessed through the @var{c}
3180 @subsection Examples
3182 Apply a denoise with a @option{sigma} of @code{4.5}:
3187 The same operation can be achieved using the expression system:
3189 dctdnoiz=e='gte(c, 4.5*3)'
3195 Drop duplicated frames at regular intervals.
3197 The filter accepts the following options:
3201 Set the number of frames from which one will be dropped. Setting this to
3202 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3203 Default is @code{5}.
3206 Set the threshold for duplicate detection. If the difference metric for a frame
3207 is less than or equal to this value, then it is declared as duplicate. Default
3211 Set scene change threshold. Default is @code{15}.
3215 Set the size of the x and y-axis blocks used during metric calculations.
3216 Larger blocks give better noise suppression, but also give worse detection of
3217 small movements. Must be a power of two. Default is @code{32}.
3220 Mark main input as a pre-processed input and activate clean source input
3221 stream. This allows the input to be pre-processed with various filters to help
3222 the metrics calculation while keeping the frame selection lossless. When set to
3223 @code{1}, the first stream is for the pre-processed input, and the second
3224 stream is the clean source from where the kept frames are chosen. Default is
3228 Set whether or not chroma is considered in the metric calculations. Default is
3234 Remove judder produced by partially interlaced telecined content.
3236 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3237 source was partially telecined content then the output of @code{pullup,dejudder}
3238 will have a variable frame rate. May change the recorded frame rate of the
3239 container. Aside from that change, this filter will not affect constant frame
3242 The option available in this filter is:
3246 Specify the length of the window over which the judder repeats.
3248 Accepts any interger greater than 1. Useful values are:
3252 If the original was telecined from 24 to 30 fps (Film to NTSC).
3255 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3258 If a mixture of the two.
3261 The default is @samp{4}.
3266 Suppress a TV station logo by a simple interpolation of the surrounding
3267 pixels. Just set a rectangle covering the logo and watch it disappear
3268 (and sometimes something even uglier appear - your mileage may vary).
3270 This filter accepts the following options:
3275 Specify the top left corner coordinates of the logo. They must be
3280 Specify the width and height of the logo to clear. They must be
3284 Specify the thickness of the fuzzy edge of the rectangle (added to
3285 @var{w} and @var{h}). The default value is 4.
3288 When set to 1, a green rectangle is drawn on the screen to simplify
3289 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3290 The default value is 0.
3292 The rectangle is drawn on the outermost pixels which will be (partly)
3293 replaced with interpolated values. The values of the next pixels
3294 immediately outside this rectangle in each direction will be used to
3295 compute the interpolated pixel values inside the rectangle.
3299 @subsection Examples
3303 Set a rectangle covering the area with top left corner coordinates 0,0
3304 and size 100x77, setting a band of size 10:
3306 delogo=x=0:y=0:w=100:h=77:band=10
3313 Attempt to fix small changes in horizontal and/or vertical shift. This
3314 filter helps remove camera shake from hand-holding a camera, bumping a
3315 tripod, moving on a vehicle, etc.
3317 The filter accepts the following options:
3325 Specify a rectangular area where to limit the search for motion
3327 If desired the search for motion vectors can be limited to a
3328 rectangular area of the frame defined by its top left corner, width
3329 and height. These parameters have the same meaning as the drawbox
3330 filter which can be used to visualise the position of the bounding
3333 This is useful when simultaneous movement of subjects within the frame
3334 might be confused for camera motion by the motion vector search.
3336 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3337 then the full frame is used. This allows later options to be set
3338 without specifying the bounding box for the motion vector search.
3340 Default - search the whole frame.
3344 Specify the maximum extent of movement in x and y directions in the
3345 range 0-64 pixels. Default 16.
3348 Specify how to generate pixels to fill blanks at the edge of the
3349 frame. Available values are:
3352 Fill zeroes at blank locations
3354 Original image at blank locations
3356 Extruded edge value at blank locations
3358 Mirrored edge at blank locations
3360 Default value is @samp{mirror}.
3363 Specify the blocksize to use for motion search. Range 4-128 pixels,
3367 Specify the contrast threshold for blocks. Only blocks with more than
3368 the specified contrast (difference between darkest and lightest
3369 pixels) will be considered. Range 1-255, default 125.
3372 Specify the search strategy. Available values are:
3375 Set exhaustive search
3377 Set less exhaustive search.
3379 Default value is @samp{exhaustive}.
3382 If set then a detailed log of the motion search is written to the
3386 If set to 1, specify using OpenCL capabilities, only available if
3387 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3393 Draw a colored box on the input image.
3395 This filter accepts the following options:
3400 The expressions which specify the top left corner coordinates of the box. Default to 0.
3404 The expressions which specify the width and height of the box, if 0 they are interpreted as
3405 the input width and height. Default to 0.
3408 Specify the color of the box to write. For the general syntax of this option,
3409 check the "Color" section in the ffmpeg-utils manual. If the special
3410 value @code{invert} is used, the box edge color is the same as the
3411 video with inverted luma.
3414 The expression which sets the thickness of the box edge. Default value is @code{3}.
3416 See below for the list of accepted constants.
3419 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3420 following constants:
3424 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3428 horizontal and vertical chroma subsample values. For example for the
3429 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3433 The input width and height.
3436 The input sample aspect ratio.
3440 The x and y offset coordinates where the box is drawn.
3444 The width and height of the drawn box.
3447 The thickness of the drawn box.
3449 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3450 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3454 @subsection Examples
3458 Draw a black box around the edge of the input image:
3464 Draw a box with color red and an opacity of 50%:
3466 drawbox=10:20:200:60:red@@0.5
3469 The previous example can be specified as:
3471 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3475 Fill the box with pink color:
3477 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3481 Draw a 2-pixel red 2.40:1 mask:
3483 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
3489 Draw a grid on the input image.
3491 This filter accepts the following options:
3496 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3500 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3501 input width and height, respectively, minus @code{thickness}, so image gets
3502 framed. Default to 0.
3505 Specify the color of the grid. For the general syntax of this option,
3506 check the "Color" section in the ffmpeg-utils manual. If the special
3507 value @code{invert} is used, the grid color is the same as the
3508 video with inverted luma.
3511 The expression which sets the thickness of the grid line. Default value is @code{1}.
3513 See below for the list of accepted constants.
3516 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3517 following constants:
3521 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3525 horizontal and vertical chroma subsample values. For example for the
3526 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3530 The input grid cell width and height.
3533 The input sample aspect ratio.
3537 The x and y coordinates of some point of grid intersection (meant to configure offset).
3541 The width and height of the drawn cell.
3544 The thickness of the drawn cell.
3546 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3547 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3551 @subsection Examples
3555 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3557 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3561 Draw a white 3x3 grid with an opacity of 50%:
3563 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3570 Draw text string or text from specified file on top of video using the
3571 libfreetype library.
3573 To enable compilation of this filter you need to configure FFmpeg with
3574 @code{--enable-libfreetype}.
3578 The description of the accepted parameters follows.
3583 Used to draw a box around text using background color.
3584 Value should be either 1 (enable) or 0 (disable).
3585 The default value of @var{box} is 0.
3588 The color to be used for drawing box around text. For the syntax of this
3589 option, check the "Color" section in the ffmpeg-utils manual.
3591 The default value of @var{boxcolor} is "white".
3594 Set the width of the border to be drawn around the text using @var{bordercolor}.
3595 The default value of @var{borderw} is 0.
3598 Set the color to be used for drawing border around text. For the syntax of this
3599 option, check the "Color" section in the ffmpeg-utils manual.
3601 The default value of @var{bordercolor} is "black".
3604 Select how the @var{text} is expanded. Can be either @code{none},
3605 @code{strftime} (deprecated) or
3606 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3610 If true, check and fix text coords to avoid clipping.
3613 The color to be used for drawing fonts. For the syntax of this option, check
3614 the "Color" section in the ffmpeg-utils manual.
3616 The default value of @var{fontcolor} is "black".
3619 The font file to be used for drawing text. Path must be included.
3620 This parameter is mandatory.
3623 The font size to be used for drawing text.
3624 The default value of @var{fontsize} is 16.
3627 Flags to be used for loading the fonts.
3629 The flags map the corresponding flags supported by libfreetype, and are
3630 a combination of the following values:
3637 @item vertical_layout
3638 @item force_autohint
3641 @item ignore_global_advance_width
3643 @item ignore_transform
3649 Default value is "default".
3651 For more information consult the documentation for the FT_LOAD_*
3655 The color to be used for drawing a shadow behind the drawn text. For the
3656 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3658 The default value of @var{shadowcolor} is "black".
3662 The x and y offsets for the text shadow position with respect to the
3663 position of the text. They can be either positive or negative
3664 values. Default value for both is "0".
3667 The starting frame number for the n/frame_num variable. The default value
3671 The size in number of spaces to use for rendering the tab.
3675 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3676 format. It can be used with or without text parameter. @var{timecode_rate}
3677 option must be specified.
3679 @item timecode_rate, rate, r
3680 Set the timecode frame rate (timecode only).
3683 The text string to be drawn. The text must be a sequence of UTF-8
3685 This parameter is mandatory if no file is specified with the parameter
3689 A text file containing text to be drawn. The text must be a sequence
3690 of UTF-8 encoded characters.
3692 This parameter is mandatory if no text string is specified with the
3693 parameter @var{text}.
3695 If both @var{text} and @var{textfile} are specified, an error is thrown.
3698 If set to 1, the @var{textfile} will be reloaded before each frame.
3699 Be sure to update it atomically, or it may be read partially, or even fail.
3703 The expressions which specify the offsets where text will be drawn
3704 within the video frame. They are relative to the top/left border of the
3707 The default value of @var{x} and @var{y} is "0".
3709 See below for the list of accepted constants and functions.
3712 The parameters for @var{x} and @var{y} are expressions containing the
3713 following constants and functions:
3717 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3721 horizontal and vertical chroma subsample values. For example for the
3722 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3725 the height of each text line
3733 @item max_glyph_a, ascent
3734 the maximum distance from the baseline to the highest/upper grid
3735 coordinate used to place a glyph outline point, for all the rendered
3737 It is a positive value, due to the grid's orientation with the Y axis
3740 @item max_glyph_d, descent
3741 the maximum distance from the baseline to the lowest grid coordinate
3742 used to place a glyph outline point, for all the rendered glyphs.
3743 This is a negative value, due to the grid's orientation, with the Y axis
3747 maximum glyph height, that is the maximum height for all the glyphs
3748 contained in the rendered text, it is equivalent to @var{ascent} -
3752 maximum glyph width, that is the maximum width for all the glyphs
3753 contained in the rendered text
3756 the number of input frame, starting from 0
3758 @item rand(min, max)
3759 return a random number included between @var{min} and @var{max}
3762 input sample aspect ratio
3765 timestamp expressed in seconds, NAN if the input timestamp is unknown
3768 the height of the rendered text
3771 the width of the rendered text
3775 the x and y offset coordinates where the text is drawn.
3777 These parameters allow the @var{x} and @var{y} expressions to refer
3778 each other, so you can for example specify @code{y=x/dar}.
3781 If libavfilter was built with @code{--enable-fontconfig}, then
3782 @option{fontfile} can be a fontconfig pattern or omitted.
3784 @anchor{drawtext_expansion}
3785 @subsection Text expansion
3787 If @option{expansion} is set to @code{strftime},
3788 the filter recognizes strftime() sequences in the provided text and
3789 expands them accordingly. Check the documentation of strftime(). This
3790 feature is deprecated.
3792 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3794 If @option{expansion} is set to @code{normal} (which is the default),
3795 the following expansion mechanism is used.
3797 The backslash character '\', followed by any character, always expands to
3798 the second character.
3800 Sequence of the form @code{%@{...@}} are expanded. The text between the
3801 braces is a function name, possibly followed by arguments separated by ':'.
3802 If the arguments contain special characters or delimiters (':' or '@}'),
3803 they should be escaped.
3805 Note that they probably must also be escaped as the value for the
3806 @option{text} option in the filter argument string and as the filter
3807 argument in the filtergraph description, and possibly also for the shell,
3808 that makes up to four levels of escaping; using a text file avoids these
3811 The following functions are available:
3816 The expression evaluation result.
3818 It must take one argument specifying the expression to be evaluated,
3819 which accepts the same constants and functions as the @var{x} and
3820 @var{y} values. Note that not all constants should be used, for
3821 example the text size is not known when evaluating the expression, so
3822 the constants @var{text_w} and @var{text_h} will have an undefined
3826 The time at which the filter is running, expressed in UTC.
3827 It can accept an argument: a strftime() format string.
3830 The time at which the filter is running, expressed in the local time zone.
3831 It can accept an argument: a strftime() format string.
3834 Frame metadata. It must take one argument specifying metadata key.
3837 The frame number, starting from 0.
3840 A 1 character description of the current picture type.
3843 The timestamp of the current frame, in seconds, with microsecond accuracy.
3847 @subsection Examples
3851 Draw "Test Text" with font FreeSerif, using the default values for the
3852 optional parameters.
3855 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
3859 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
3860 and y=50 (counting from the top-left corner of the screen), text is
3861 yellow with a red box around it. Both the text and the box have an
3865 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
3866 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
3869 Note that the double quotes are not necessary if spaces are not used
3870 within the parameter list.
3873 Show the text at the center of the video frame:
3875 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
3879 Show a text line sliding from right to left in the last row of the video
3880 frame. The file @file{LONG_LINE} is assumed to contain a single line
3883 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
3887 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
3889 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
3893 Draw a single green letter "g", at the center of the input video.
3894 The glyph baseline is placed at half screen height.
3896 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
3900 Show text for 1 second every 3 seconds:
3902 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
3906 Use fontconfig to set the font. Note that the colons need to be escaped.
3908 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
3912 Print the date of a real-time encoding (see strftime(3)):
3914 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
3919 For more information about libfreetype, check:
3920 @url{http://www.freetype.org/}.
3922 For more information about fontconfig, check:
3923 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
3927 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
3929 The filter accepts the following options:
3934 Set low and high threshold values used by the Canny thresholding
3937 The high threshold selects the "strong" edge pixels, which are then
3938 connected through 8-connectivity with the "weak" edge pixels selected
3939 by the low threshold.
3941 @var{low} and @var{high} threshold values must be chosen in the range
3942 [0,1], and @var{low} should be lesser or equal to @var{high}.
3944 Default value for @var{low} is @code{20/255}, and default value for @var{high}
3950 edgedetect=low=0.1:high=0.4
3953 @section extractplanes
3955 Extract color channel components from input video stream into
3956 separate grayscale video streams.
3958 The filter accepts the following option:
3962 Set plane(s) to extract.
3964 Available values for planes are:
3975 Choosing planes not available in the input will result in an error.
3976 That means you cannot select @code{r}, @code{g}, @code{b} planes
3977 with @code{y}, @code{u}, @code{v} planes at same time.
3980 @subsection Examples
3984 Extract luma, u and v color channel component from input video frame
3985 into 3 grayscale outputs:
3987 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
3993 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
3995 For each input image, the filter will compute the optimal mapping from
3996 the input to the output given the codebook length, that is the number
3997 of distinct output colors.
3999 This filter accepts the following options.
4002 @item codebook_length, l
4003 Set codebook length. The value must be a positive integer, and
4004 represents the number of distinct output colors. Default value is 256.
4007 Set the maximum number of iterations to apply for computing the optimal
4008 mapping. The higher the value the better the result and the higher the
4009 computation time. Default value is 1.
4012 Set a random seed, must be an integer included between 0 and
4013 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4014 will try to use a good random seed on a best effort basis.
4019 Apply fade-in/out effect to input video.
4021 This filter accepts the following options:
4025 The effect type -- can be either "in" for fade-in, or "out" for a fade-out
4027 Default is @code{in}.
4029 @item start_frame, s
4030 Specify the number of the start frame for starting to apply the fade
4031 effect. Default is 0.
4034 The number of frames for which the fade effect has to last. At the end of the
4035 fade-in effect the output video will have the same intensity as the input video,
4036 at the end of the fade-out transition the output video will be filled with the
4037 selected @option{color}.
4041 If set to 1, fade only alpha channel, if one exists on the input.
4044 @item start_time, st
4045 Specify the timestamp (in seconds) of the frame to start to apply the fade
4046 effect. If both start_frame and start_time are specified, the fade will start at
4047 whichever comes last. Default is 0.
4050 The number of seconds for which the fade effect has to last. At the end of the
4051 fade-in effect the output video will have the same intensity as the input video,
4052 at the end of the fade-out transition the output video will be filled with the
4053 selected @option{color}.
4054 If both duration and nb_frames are specified, duration is used. Default is 0.
4057 Specify the color of the fade. Default is "black".
4060 @subsection Examples
4064 Fade in first 30 frames of video:
4069 The command above is equivalent to:
4075 Fade out last 45 frames of a 200-frame video:
4078 fade=type=out:start_frame=155:nb_frames=45
4082 Fade in first 25 frames and fade out last 25 frames of a 1000-frame video:
4084 fade=in:0:25, fade=out:975:25
4088 Make first 5 frames yellow, then fade in from frame 5-24:
4090 fade=in:5:20:color=yellow
4094 Fade in alpha over first 25 frames of video:
4096 fade=in:0:25:alpha=1
4100 Make first 5.5 seconds black, then fade in for 0.5 seconds:
4102 fade=t=in:st=5.5:d=0.5
4109 Extract a single field from an interlaced image using stride
4110 arithmetic to avoid wasting CPU time. The output frames are marked as
4113 The filter accepts the following options:
4117 Specify whether to extract the top (if the value is @code{0} or
4118 @code{top}) or the bottom field (if the value is @code{1} or
4124 Field matching filter for inverse telecine. It is meant to reconstruct the
4125 progressive frames from a telecined stream. The filter does not drop duplicated
4126 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4127 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4129 The separation of the field matching and the decimation is notably motivated by
4130 the possibility of inserting a de-interlacing filter fallback between the two.
4131 If the source has mixed telecined and real interlaced content,
4132 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4133 But these remaining combed frames will be marked as interlaced, and thus can be
4134 de-interlaced by a later filter such as @ref{yadif} before decimation.
4136 In addition to the various configuration options, @code{fieldmatch} can take an
4137 optional second stream, activated through the @option{ppsrc} option. If
4138 enabled, the frames reconstruction will be based on the fields and frames from
4139 this second stream. This allows the first input to be pre-processed in order to
4140 help the various algorithms of the filter, while keeping the output lossless
4141 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4142 or brightness/contrast adjustments can help.
4144 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4145 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4146 which @code{fieldmatch} is based on. While the semantic and usage are very
4147 close, some behaviour and options names can differ.
4149 The filter accepts the following options:
4153 Specify the assumed field order of the input stream. Available values are:
4157 Auto detect parity (use FFmpeg's internal parity value).
4159 Assume bottom field first.
4161 Assume top field first.
4164 Note that it is sometimes recommended not to trust the parity announced by the
4167 Default value is @var{auto}.
4170 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4171 sense that it won't risk creating jerkiness due to duplicate frames when
4172 possible, but if there are bad edits or blended fields it will end up
4173 outputting combed frames when a good match might actually exist. On the other
4174 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4175 but will almost always find a good frame if there is one. The other values are
4176 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4177 jerkiness and creating duplicate frames versus finding good matches in sections
4178 with bad edits, orphaned fields, blended fields, etc.
4180 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4182 Available values are:
4186 2-way matching (p/c)
4188 2-way matching, and trying 3rd match if still combed (p/c + n)
4190 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4192 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4193 still combed (p/c + n + u/b)
4195 3-way matching (p/c/n)
4197 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4198 detected as combed (p/c/n + u/b)
4201 The parenthesis at the end indicate the matches that would be used for that
4202 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4205 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4208 Default value is @var{pc_n}.
4211 Mark the main input stream as a pre-processed input, and enable the secondary
4212 input stream as the clean source to pick the fields from. See the filter
4213 introduction for more details. It is similar to the @option{clip2} feature from
4216 Default value is @code{0} (disabled).
4219 Set the field to match from. It is recommended to set this to the same value as
4220 @option{order} unless you experience matching failures with that setting. In
4221 certain circumstances changing the field that is used to match from can have a
4222 large impact on matching performance. Available values are:
4226 Automatic (same value as @option{order}).
4228 Match from the bottom field.
4230 Match from the top field.
4233 Default value is @var{auto}.
4236 Set whether or not chroma is included during the match comparisons. In most
4237 cases it is recommended to leave this enabled. You should set this to @code{0}
4238 only if your clip has bad chroma problems such as heavy rainbowing or other
4239 artifacts. Setting this to @code{0} could also be used to speed things up at
4240 the cost of some accuracy.
4242 Default value is @code{1}.
4246 These define an exclusion band which excludes the lines between @option{y0} and
4247 @option{y1} from being included in the field matching decision. An exclusion
4248 band can be used to ignore subtitles, a logo, or other things that may
4249 interfere with the matching. @option{y0} sets the starting scan line and
4250 @option{y1} sets the ending line; all lines in between @option{y0} and
4251 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4252 @option{y0} and @option{y1} to the same value will disable the feature.
4253 @option{y0} and @option{y1} defaults to @code{0}.
4256 Set the scene change detection threshold as a percentage of maximum change on
4257 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4258 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4259 @option{scthresh} is @code{[0.0, 100.0]}.
4261 Default value is @code{12.0}.
4264 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4265 account the combed scores of matches when deciding what match to use as the
4266 final match. Available values are:
4270 No final matching based on combed scores.
4272 Combed scores are only used when a scene change is detected.
4274 Use combed scores all the time.
4277 Default is @var{sc}.
4280 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4281 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4282 Available values are:
4286 No forced calculation.
4288 Force p/c/n calculations.
4290 Force p/c/n/u/b calculations.
4293 Default value is @var{none}.
4296 This is the area combing threshold used for combed frame detection. This
4297 essentially controls how "strong" or "visible" combing must be to be detected.
4298 Larger values mean combing must be more visible and smaller values mean combing
4299 can be less visible or strong and still be detected. Valid settings are from
4300 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4301 be detected as combed). This is basically a pixel difference value. A good
4302 range is @code{[8, 12]}.
4304 Default value is @code{9}.
4307 Sets whether or not chroma is considered in the combed frame decision. Only
4308 disable this if your source has chroma problems (rainbowing, etc.) that are
4309 causing problems for the combed frame detection with chroma enabled. Actually,
4310 using @option{chroma}=@var{0} is usually more reliable, except for the case
4311 where there is chroma only combing in the source.
4313 Default value is @code{0}.
4317 Respectively set the x-axis and y-axis size of the window used during combed
4318 frame detection. This has to do with the size of the area in which
4319 @option{combpel} pixels are required to be detected as combed for a frame to be
4320 declared combed. See the @option{combpel} parameter description for more info.
4321 Possible values are any number that is a power of 2 starting at 4 and going up
4324 Default value is @code{16}.
4327 The number of combed pixels inside any of the @option{blocky} by
4328 @option{blockx} size blocks on the frame for the frame to be detected as
4329 combed. While @option{cthresh} controls how "visible" the combing must be, this
4330 setting controls "how much" combing there must be in any localized area (a
4331 window defined by the @option{blockx} and @option{blocky} settings) on the
4332 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4333 which point no frames will ever be detected as combed). This setting is known
4334 as @option{MI} in TFM/VFM vocabulary.
4336 Default value is @code{80}.
4339 @anchor{p/c/n/u/b meaning}
4340 @subsection p/c/n/u/b meaning
4342 @subsubsection p/c/n
4344 We assume the following telecined stream:
4347 Top fields: 1 2 2 3 4
4348 Bottom fields: 1 2 3 4 4
4351 The numbers correspond to the progressive frame the fields relate to. Here, the
4352 first two frames are progressive, the 3rd and 4th are combed, and so on.
4354 When @code{fieldmatch} is configured to run a matching from bottom
4355 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4360 B 1 2 3 4 4 <-- matching reference
4369 As a result of the field matching, we can see that some frames get duplicated.
4370 To perform a complete inverse telecine, you need to rely on a decimation filter
4371 after this operation. See for instance the @ref{decimate} filter.
4373 The same operation now matching from top fields (@option{field}=@var{top})
4378 T 1 2 2 3 4 <-- matching reference
4388 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4389 basically, they refer to the frame and field of the opposite parity:
4392 @item @var{p} matches the field of the opposite parity in the previous frame
4393 @item @var{c} matches the field of the opposite parity in the current frame
4394 @item @var{n} matches the field of the opposite parity in the next frame
4399 The @var{u} and @var{b} matching are a bit special in the sense that they match
4400 from the opposite parity flag. In the following examples, we assume that we are
4401 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4402 'x' is placed above and below each matched fields.
4404 With bottom matching (@option{field}=@var{bottom}):
4409 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4410 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4418 With top matching (@option{field}=@var{top}):
4423 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4424 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4432 @subsection Examples
4434 Simple IVTC of a top field first telecined stream:
4436 fieldmatch=order=tff:combmatch=none, decimate
4439 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4441 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4446 Transform the field order of the input video.
4448 This filter accepts the following options:
4453 Output field order. Valid values are @var{tff} for top field first or @var{bff}
4454 for bottom field first.
4457 Default value is @samp{tff}.
4459 Transformation is achieved by shifting the picture content up or down
4460 by one line, and filling the remaining line with appropriate picture content.
4461 This method is consistent with most broadcast field order converters.
4463 If the input video is not flagged as being interlaced, or it is already
4464 flagged as being of the required output field order then this filter does
4465 not alter the incoming video.
4467 This filter is very useful when converting to or from PAL DV material,
4468 which is bottom field first.
4472 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4477 Buffer input images and send them when they are requested.
4479 This filter is mainly useful when auto-inserted by the libavfilter
4482 The filter does not take parameters.
4487 Convert the input video to one of the specified pixel formats.
4488 Libavfilter will try to pick one that is supported for the input to
4491 This filter accepts the following parameters:
4495 A '|'-separated list of pixel format names, for example
4496 "pix_fmts=yuv420p|monow|rgb24".
4500 @subsection Examples
4504 Convert the input video to the format @var{yuv420p}
4506 format=pix_fmts=yuv420p
4509 Convert the input video to any of the formats in the list
4511 format=pix_fmts=yuv420p|yuv444p|yuv410p
4518 Convert the video to specified constant frame rate by duplicating or dropping
4519 frames as necessary.
4521 This filter accepts the following named parameters:
4525 Desired output frame rate. The default is @code{25}.
4530 Possible values are:
4533 zero round towards 0
4537 round towards -infinity
4539 round towards +infinity
4543 The default is @code{near}.
4546 Assume the first PTS should be the given value, in seconds. This allows for
4547 padding/trimming at the start of stream. By default, no assumption is made
4548 about the first frame's expected PTS, so no padding or trimming is done.
4549 For example, this could be set to 0 to pad the beginning with duplicates of
4550 the first frame if a video stream starts after the audio stream or to trim any
4551 frames with a negative PTS.
4555 Alternatively, the options can be specified as a flat string:
4556 @var{fps}[:@var{round}].
4558 See also the @ref{setpts} filter.
4560 @subsection Examples
4564 A typical usage in order to set the fps to 25:
4570 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4572 fps=fps=film:round=near
4578 Pack two different video streams into a stereoscopic video, setting proper
4579 metadata on supported codecs. The two views should have the same size and
4580 framerate and processing will stop when the shorter video ends. Please note
4581 that you may conveniently adjust view properties with the @ref{scale} and
4584 This filter accepts the following named parameters:
4588 Desired packing format. Supported values are:
4593 Views are next to each other (default).
4596 Views are on top of each other.
4599 Views are packed by line.
4602 Views are eacked by column.
4605 Views are temporally interleaved.
4611 Some examples follow:
4614 # Convert left and right views into a frame sequential video.
4615 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
4617 # Convert views into a side-by-side video with the same output resolution as the input.
4618 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
4623 Select one frame every N-th frame.
4625 This filter accepts the following option:
4628 Select frame after every @code{step} frames.
4629 Allowed values are positive integers higher than 0. Default value is @code{1}.
4635 Apply a frei0r effect to the input video.
4637 To enable compilation of this filter you need to install the frei0r
4638 header and configure FFmpeg with @code{--enable-frei0r}.
4640 This filter accepts the following options:
4645 The name to the frei0r effect to load. If the environment variable
4646 @env{FREI0R_PATH} is defined, the frei0r effect is searched in each one of the
4647 directories specified by the colon separated list in @env{FREIOR_PATH},
4648 otherwise in the standard frei0r paths, which are in this order:
4649 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
4650 @file{/usr/lib/frei0r-1/}.
4653 A '|'-separated list of parameters to pass to the frei0r effect.
4657 A frei0r effect parameter can be a boolean (whose values are specified
4658 with "y" and "n"), a double, a color (specified by the syntax
4659 @var{R}/@var{G}/@var{B}, (@var{R}, @var{G}, and @var{B} being float
4660 numbers from 0.0 to 1.0) or by a color description specified in the "Color"
4661 section in the ffmpeg-utils manual), a position (specified by the syntax @var{X}/@var{Y},
4662 @var{X} and @var{Y} being float numbers) and a string.
4664 The number and kind of parameters depend on the loaded effect. If an
4665 effect parameter is not specified the default value is set.
4667 @subsection Examples
4671 Apply the distort0r effect, set the first two double parameters:
4673 frei0r=filter_name=distort0r:filter_params=0.5|0.01
4677 Apply the colordistance effect, take a color as first parameter:
4679 frei0r=colordistance:0.2/0.3/0.4
4680 frei0r=colordistance:violet
4681 frei0r=colordistance:0x112233
4685 Apply the perspective effect, specify the top left and top right image
4688 frei0r=perspective:0.2/0.2|0.8/0.2
4692 For more information see:
4693 @url{http://frei0r.dyne.org}
4697 The filter accepts the following options:
4701 Set the luminance expression.
4703 Set the chrominance blue expression.
4705 Set the chrominance red expression.
4707 Set the alpha expression.
4709 Set the red expression.
4711 Set the green expression.
4713 Set the blue expression.
4716 The colorspace is selected according to the specified options. If one
4717 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4718 options is specified, the filter will automatically select a YCbCr
4719 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4720 @option{blue_expr} options is specified, it will select an RGB
4723 If one of the chrominance expression is not defined, it falls back on the other
4724 one. If no alpha expression is specified it will evaluate to opaque value.
4725 If none of chrominance expressions are specified, they will evaluate
4726 to the luminance expression.
4728 The expressions can use the following variables and functions:
4732 The sequential number of the filtered frame, starting from @code{0}.
4736 The coordinates of the current sample.
4740 The width and height of the image.
4744 Width and height scale depending on the currently filtered plane. It is the
4745 ratio between the corresponding luma plane number of pixels and the current
4746 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4747 @code{0.5,0.5} for chroma planes.
4750 Time of the current frame, expressed in seconds.
4753 Return the value of the pixel at location (@var{x},@var{y}) of the current
4757 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
4761 Return the value of the pixel at location (@var{x},@var{y}) of the
4762 blue-difference chroma plane. Return 0 if there is no such plane.
4765 Return the value of the pixel at location (@var{x},@var{y}) of the
4766 red-difference chroma plane. Return 0 if there is no such plane.
4771 Return the value of the pixel at location (@var{x},@var{y}) of the
4772 red/green/blue component. Return 0 if there is no such component.
4775 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
4776 plane. Return 0 if there is no such plane.
4779 For functions, if @var{x} and @var{y} are outside the area, the value will be
4780 automatically clipped to the closer edge.
4782 @subsection Examples
4786 Flip the image horizontally:
4792 Generate a bidimensional sine wave, with angle @code{PI/3} and a
4793 wavelength of 100 pixels:
4795 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
4799 Generate a fancy enigmatic moving light:
4801 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
4805 Generate a quick emboss effect:
4807 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
4811 Modify RGB components depending on pixel position:
4813 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
4819 Fix the banding artifacts that are sometimes introduced into nearly flat
4820 regions by truncation to 8bit color depth.
4821 Interpolate the gradients that should go where the bands are, and
4824 This filter is designed for playback only. Do not use it prior to
4825 lossy compression, because compression tends to lose the dither and
4826 bring back the bands.
4828 This filter accepts the following options:
4833 The maximum amount by which the filter will change any one pixel. Also the
4834 threshold for detecting nearly flat regions. Acceptable values range from .51 to
4835 64, default value is 1.2, out-of-range values will be clipped to the valid
4839 The neighborhood to fit the gradient to. A larger radius makes for smoother
4840 gradients, but also prevents the filter from modifying the pixels near detailed
4841 regions. Acceptable values are 8-32, default value is 16, out-of-range values
4842 will be clipped to the valid range.
4846 Alternatively, the options can be specified as a flat string:
4847 @var{strength}[:@var{radius}]
4849 @subsection Examples
4853 Apply the filter with a @code{3.5} strength and radius of @code{8}:
4859 Specify radius, omitting the strength (which will fall-back to the default
4870 Apply a Hald CLUT to a video stream.
4872 First input is the video stream to process, and second one is the Hald CLUT.
4873 The Hald CLUT input can be a simple picture or a complete video stream.
4875 The filter accepts the following options:
4879 Force termination when the shortest input terminates. Default is @code{0}.
4881 Continue applying the last CLUT after the end of the stream. A value of
4882 @code{0} disable the filter after the last frame of the CLUT is reached.
4883 Default is @code{1}.
4886 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
4887 filters share the same internals).
4889 More information about the Hald CLUT can be found on Eskil Steenberg's website
4890 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
4892 @subsection Workflow examples
4894 @subsubsection Hald CLUT video stream
4896 Generate an identity Hald CLUT stream altered with various effects:
4898 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
4901 Note: make sure you use a lossless codec.
4903 Then use it with @code{haldclut} to apply it on some random stream:
4905 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
4908 The Hald CLUT will be applied to the 10 first seconds (duration of
4909 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
4910 to the remaining frames of the @code{mandelbrot} stream.
4912 @subsubsection Hald CLUT with preview
4914 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
4915 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
4916 biggest possible square starting at the top left of the picture. The remaining
4917 padding pixels (bottom or right) will be ignored. This area can be used to add
4918 a preview of the Hald CLUT.
4920 Typically, the following generated Hald CLUT will be supported by the
4921 @code{haldclut} filter:
4924 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
4925 pad=iw+320 [padded_clut];
4926 smptebars=s=320x256, split [a][b];
4927 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
4928 [main][b] overlay=W-320" -frames:v 1 clut.png
4931 It contains the original and a preview of the effect of the CLUT: SMPTE color
4932 bars are displayed on the right-top, and below the same color bars processed by
4935 Then, the effect of this Hald CLUT can be visualized with:
4937 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
4942 Flip the input video horizontally.
4944 For example to horizontally flip the input video with @command{ffmpeg}:
4946 ffmpeg -i in.avi -vf "hflip" out.avi
4950 This filter applies a global color histogram equalization on a
4953 It can be used to correct video that has a compressed range of pixel
4954 intensities. The filter redistributes the pixel intensities to
4955 equalize their distribution across the intensity range. It may be
4956 viewed as an "automatically adjusting contrast filter". This filter is
4957 useful only for correcting degraded or poorly captured source
4960 The filter accepts the following options:
4964 Determine the amount of equalization to be applied. As the strength
4965 is reduced, the distribution of pixel intensities more-and-more
4966 approaches that of the input frame. The value must be a float number
4967 in the range [0,1] and defaults to 0.200.
4970 Set the maximum intensity that can generated and scale the output
4971 values appropriately. The strength should be set as desired and then
4972 the intensity can be limited if needed to avoid washing-out. The value
4973 must be a float number in the range [0,1] and defaults to 0.210.
4976 Set the antibanding level. If enabled the filter will randomly vary
4977 the luminance of output pixels by a small amount to avoid banding of
4978 the histogram. Possible values are @code{none}, @code{weak} or
4979 @code{strong}. It defaults to @code{none}.
4984 Compute and draw a color distribution histogram for the input video.
4986 The computed histogram is a representation of the color component
4987 distribution in an image.
4989 The filter accepts the following options:
4995 It accepts the following values:
4998 Standard histogram that displays the color components distribution in an
4999 image. Displays color graph for each color component. Shows distribution of
5000 the Y, U, V, A or R, G, B components, depending on input format, in the
5001 current frame. Below each graph a color component scale meter is shown.
5004 Displays chroma values (U/V color placement) in a two dimensional
5005 graph (which is called a vectorscope). The brighter a pixel in the
5006 vectorscope, the more pixels of the input frame correspond to that pixel
5007 (i.e., more pixels have this chroma value). The V component is displayed on
5008 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5009 side being V = 255. The U component is displayed on the vertical (Y) axis,
5010 with the top representing U = 0 and the bottom representing U = 255.
5012 The position of a white pixel in the graph corresponds to the chroma value of
5013 a pixel of the input clip. The graph can therefore be used to read the hue
5014 (color flavor) and the saturation (the dominance of the hue in the color). As
5015 the hue of a color changes, it moves around the square. At the center of the
5016 square the saturation is zero, which means that the corresponding pixel has no
5017 color. If the amount of a specific color is increased (while leaving the other
5018 colors unchanged) the saturation increases, and the indicator moves towards
5019 the edge of the square.
5022 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5026 Per row/column color component graph. In row mode, the graph on the left side
5027 represents color component value 0 and the right side represents value = 255.
5028 In column mode, the top side represents color component value = 0 and bottom
5029 side represents value = 255.
5031 Default value is @code{levels}.
5034 Set height of level in @code{levels}. Default value is @code{200}.
5035 Allowed range is [50, 2048].
5038 Set height of color scale in @code{levels}. Default value is @code{12}.
5039 Allowed range is [0, 40].
5042 Set step for @code{waveform} mode. Smaller values are useful to find out how
5043 many values of the same luminance are distributed across input rows/columns.
5044 Default value is @code{10}. Allowed range is [1, 255].
5047 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5048 Default is @code{row}.
5050 @item waveform_mirror
5051 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5052 means mirrored. In mirrored mode, higher values will be represented on the left
5053 side for @code{row} mode and at the top for @code{column} mode. Default is
5054 @code{0} (unmirrored).
5057 Set display mode for @code{waveform} and @code{levels}.
5058 It accepts the following values:
5061 Display separate graph for the color components side by side in
5062 @code{row} waveform mode or one below the other in @code{column} waveform mode
5063 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5064 per color component graphs are placed below each other.
5066 Using this display mode in @code{waveform} histogram mode makes it easy to
5067 spot color casts in the highlights and shadows of an image, by comparing the
5068 contours of the top and the bottom graphs of each waveform. Since whites,
5069 grays, and blacks are characterized by exactly equal amounts of red, green,
5070 and blue, neutral areas of the picture should display three waveforms of
5071 roughly equal width/height. If not, the correction is easy to perform by
5072 making level adjustments the three waveforms.
5075 Presents information identical to that in the @code{parade}, except
5076 that the graphs representing color components are superimposed directly
5079 This display mode in @code{waveform} histogram mode makes it easier to spot
5080 relative differences or similarities in overlapping areas of the color
5081 components that are supposed to be identical, such as neutral whites, grays,
5084 Default is @code{parade}.
5087 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5088 Default is @code{linear}.
5091 @subsection Examples
5096 Calculate and draw histogram:
5098 ffplay -i input -vf histogram
5106 High precision/quality 3d denoise filter. This filter aims to reduce
5107 image noise producing smooth images and making still images really
5108 still. It should enhance compressibility.
5110 It accepts the following optional parameters:
5114 a non-negative float number which specifies spatial luma strength,
5117 @item chroma_spatial
5118 a non-negative float number which specifies spatial chroma strength,
5119 defaults to 3.0*@var{luma_spatial}/4.0
5122 a float number which specifies luma temporal strength, defaults to
5123 6.0*@var{luma_spatial}/4.0
5126 a float number which specifies chroma temporal strength, defaults to
5127 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
5132 Modify the hue and/or the saturation of the input.
5134 This filter accepts the following options:
5138 Specify the hue angle as a number of degrees. It accepts an expression,
5139 and defaults to "0".
5142 Specify the saturation in the [-10,10] range. It accepts an expression and
5146 Specify the hue angle as a number of radians. It accepts an
5147 expression, and defaults to "0".
5150 Specify the brightness in the [-10,10] range. It accepts an expression and
5154 @option{h} and @option{H} are mutually exclusive, and can't be
5155 specified at the same time.
5157 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5158 expressions containing the following constants:
5162 frame count of the input frame starting from 0
5165 presentation timestamp of the input frame expressed in time base units
5168 frame rate of the input video, NAN if the input frame rate is unknown
5171 timestamp expressed in seconds, NAN if the input timestamp is unknown
5174 time base of the input video
5177 @subsection Examples
5181 Set the hue to 90 degrees and the saturation to 1.0:
5187 Same command but expressing the hue in radians:
5193 Rotate hue and make the saturation swing between 0
5194 and 2 over a period of 1 second:
5196 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5200 Apply a 3 seconds saturation fade-in effect starting at 0:
5205 The general fade-in expression can be written as:
5207 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5211 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5213 hue="s=max(0\, min(1\, (8-t)/3))"
5216 The general fade-out expression can be written as:
5218 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5223 @subsection Commands
5225 This filter supports the following commands:
5231 Modify the hue and/or the saturation and/or brightness of the input video.
5232 The command accepts the same syntax of the corresponding option.
5234 If the specified expression is not valid, it is kept at its current
5240 Detect video interlacing type.
5242 This filter tries to detect if the input is interlaced or progressive,
5243 top or bottom field first.
5245 The filter accepts the following options:
5249 Set interlacing threshold.
5251 Set progressive threshold.
5256 Deinterleave or interleave fields.
5258 This filter allows one to process interlaced images fields without
5259 deinterlacing them. Deinterleaving splits the input frame into 2
5260 fields (so called half pictures). Odd lines are moved to the top
5261 half of the output image, even lines to the bottom half.
5262 You can process (filter) them independently and then re-interleave them.
5264 The filter accepts the following options:
5268 @item chroma_mode, c
5270 Available values for @var{luma_mode}, @var{chroma_mode} and
5271 @var{alpha_mode} are:
5277 @item deinterleave, d
5278 Deinterleave fields, placing one above the other.
5281 Interleave fields. Reverse the effect of deinterleaving.
5283 Default value is @code{none}.
5286 @item chroma_swap, cs
5287 @item alpha_swap, as
5288 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5293 Simple interlacing filter from progressive contents. This interleaves upper (or
5294 lower) lines from odd frames with lower (or upper) lines from even frames,
5295 halving the frame rate and preserving image height. A vertical lowpass filter
5296 is always applied in order to avoid twitter effects and reduce moiré patterns.
5299 Original Original New Frame
5300 Frame 'j' Frame 'j+1' (tff)
5301 ========== =========== ==================
5302 Line 0 --------------------> Frame 'j' Line 0
5303 Line 1 Line 1 ----> Frame 'j+1' Line 1
5304 Line 2 ---------------------> Frame 'j' Line 2
5305 Line 3 Line 3 ----> Frame 'j+1' Line 3
5307 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5310 It accepts the following optional parameters:
5314 determines whether the interlaced frame is taken from the even (tff - default)
5315 or odd (bff) lines of the progressive frame.
5320 Deinterlace input video by applying Donald Graft's adaptive kernel
5321 deinterling. Work on interlaced parts of a video to produce
5324 The description of the accepted parameters follows.
5328 Set the threshold which affects the filter's tolerance when
5329 determining if a pixel line must be processed. It must be an integer
5330 in the range [0,255] and defaults to 10. A value of 0 will result in
5331 applying the process on every pixels.
5334 Paint pixels exceeding the threshold value to white if set to 1.
5338 Set the fields order. Swap fields if set to 1, leave fields alone if
5342 Enable additional sharpening if set to 1. Default is 0.
5345 Enable twoway sharpening if set to 1. Default is 0.
5348 @subsection Examples
5352 Apply default values:
5354 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5358 Enable additional sharpening:
5364 Paint processed pixels in white:
5373 Apply a 3D LUT to an input video.
5375 The filter accepts the following options:
5379 Set the 3D LUT file name.
5381 Currently supported formats:
5393 Select interpolation mode.
5395 Available values are:
5399 Use values from the nearest defined point.
5401 Interpolate values using the 8 points defining a cube.
5403 Interpolate values using a tetrahedron.
5407 @section lut, lutrgb, lutyuv
5409 Compute a look-up table for binding each pixel component input value
5410 to an output value, and apply it to input video.
5412 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5413 to an RGB input video.
5415 These filters accept the following options:
5418 set first pixel component expression
5420 set second pixel component expression
5422 set third pixel component expression
5424 set fourth pixel component expression, corresponds to the alpha component
5427 set red component expression
5429 set green component expression
5431 set blue component expression
5433 alpha component expression
5436 set Y/luminance component expression
5438 set U/Cb component expression
5440 set V/Cr component expression
5443 Each of them specifies the expression to use for computing the lookup table for
5444 the corresponding pixel component values.
5446 The exact component associated to each of the @var{c*} options depends on the
5449 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5450 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5452 The expressions can contain the following constants and functions:
5457 the input width and height
5460 input value for the pixel component
5463 the input value clipped in the @var{minval}-@var{maxval} range
5466 maximum value for the pixel component
5469 minimum value for the pixel component
5472 the negated value for the pixel component value clipped in the
5473 @var{minval}-@var{maxval} range , it corresponds to the expression
5474 "maxval-clipval+minval"
5477 the computed value in @var{val} clipped in the
5478 @var{minval}-@var{maxval} range
5480 @item gammaval(gamma)
5481 the computed gamma correction value of the pixel component value
5482 clipped in the @var{minval}-@var{maxval} range, corresponds to the
5484 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
5488 All expressions default to "val".
5490 @subsection Examples
5496 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
5497 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
5500 The above is the same as:
5502 lutrgb="r=negval:g=negval:b=negval"
5503 lutyuv="y=negval:u=negval:v=negval"
5513 Remove chroma components, turns the video into a graytone image:
5515 lutyuv="u=128:v=128"
5519 Apply a luma burning effect:
5525 Remove green and blue components:
5531 Set a constant alpha channel value on input:
5533 format=rgba,lutrgb=a="maxval-minval/2"
5537 Correct luminance gamma by a 0.5 factor:
5539 lutyuv=y=gammaval(0.5)
5543 Discard least significant bits of luma:
5545 lutyuv=y='bitand(val, 128+64+32)'
5549 @section mergeplanes
5551 Merge color channel components from several video streams.
5553 The filter accepts up to 4 input streams, and merge selected input
5554 planes to the output video.
5556 This filter accepts the following options:
5559 Set input to output plane mapping. Default is @code{0}.
5561 The mappings is specified as a bitmap. It should be specified as a
5562 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
5563 mapping for the first plane of the output stream. 'A' sets the number of
5564 the input stream to use (from 0 to 3), and 'a' the plane number of the
5565 corresponding input to use (from 0 to 3). The rest of the mappings is
5566 similar, 'Bb' describes the mapping for the output stream second
5567 plane, 'Cc' describes the mapping for the output stream third plane and
5568 'Dd' describes the mapping for the output stream fourth plane.
5571 Set output pixel format. Default is @code{yuva444p}.
5574 @subsection Examples
5578 Merge three gray video streams of same width and height into single video stream:
5580 [a0][a1][a2]mergeplanes=0x001020:yuv444p
5584 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
5586 [a0][a1]mergeplanes=0x00010210:yuva444p
5590 Swap Y and A plane in yuva444p stream:
5592 format=yuva444p,mergeplanes=0x03010200:yuva444p
5596 Swap U and V plane in yuv420p stream:
5598 format=yuv420p,mergeplanes=0x000201:yuv420p
5602 Cast a rgb24 clip to yuv444p:
5604 format=rgb24,mergeplanes=0x000102:yuv444p
5610 Apply motion-compensation deinterlacing.
5612 It needs one field per frame as input and must thus be used together
5613 with yadif=1/3 or equivalent.
5615 This filter accepts the following options:
5618 Set the deinterlacing mode.
5620 It accepts one of the following values:
5625 use iterative motion estimation
5627 like @samp{slow}, but use multiple reference frames.
5629 Default value is @samp{fast}.
5632 Set the picture field parity assumed for the input video. It must be
5633 one of the following values:
5637 assume top field first
5639 assume bottom field first
5642 Default value is @samp{bff}.
5645 Set per-block quantization parameter (QP) used by the internal
5648 Higher values should result in a smoother motion vector field but less
5649 optimal individual vectors. Default value is 1.
5654 Apply an MPlayer filter to the input video.
5656 This filter provides a wrapper around some of the filters of
5659 This wrapper is considered experimental. Some of the wrapped filters
5660 may not work properly and we may drop support for them, as they will
5661 be implemented natively into FFmpeg. Thus you should avoid
5662 depending on them when writing portable scripts.
5664 The filter accepts the parameters:
5665 @var{filter_name}[:=]@var{filter_params}
5667 @var{filter_name} is the name of a supported MPlayer filter,
5668 @var{filter_params} is a string containing the parameters accepted by
5671 The list of the currently supported filters follows:
5682 The parameter syntax and behavior for the listed filters are the same
5683 of the corresponding MPlayer filters. For detailed instructions check
5684 the "VIDEO FILTERS" section in the MPlayer manual.
5686 @subsection Examples
5690 Adjust gamma, brightness, contrast:
5696 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
5700 Drop frames that do not differ greatly from the previous frame in
5701 order to reduce frame rate.
5703 The main use of this filter is for very-low-bitrate encoding
5704 (e.g. streaming over dialup modem), but it could in theory be used for
5705 fixing movies that were inverse-telecined incorrectly.
5707 A description of the accepted options follows.
5711 Set the maximum number of consecutive frames which can be dropped (if
5712 positive), or the minimum interval between dropped frames (if
5713 negative). If the value is 0, the frame is dropped unregarding the
5714 number of previous sequentially dropped frames.
5721 Set the dropping threshold values.
5723 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
5724 represent actual pixel value differences, so a threshold of 64
5725 corresponds to 1 unit of difference for each pixel, or the same spread
5726 out differently over the block.
5728 A frame is a candidate for dropping if no 8x8 blocks differ by more
5729 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
5730 meaning the whole image) differ by more than a threshold of @option{lo}.
5732 Default value for @option{hi} is 64*12, default value for @option{lo} is
5733 64*5, and default value for @option{frac} is 0.33.
5741 This filter accepts an integer in input, if non-zero it negates the
5742 alpha component (if available). The default value in input is 0.
5746 Force libavfilter not to use any of the specified pixel formats for the
5747 input to the next filter.
5749 This filter accepts the following parameters:
5753 A '|'-separated list of pixel format names, for example
5754 "pix_fmts=yuv420p|monow|rgb24".
5758 @subsection Examples
5762 Force libavfilter to use a format different from @var{yuv420p} for the
5763 input to the vflip filter:
5765 noformat=pix_fmts=yuv420p,vflip
5769 Convert the input video to any of the formats not contained in the list:
5771 noformat=yuv420p|yuv444p|yuv410p
5777 Add noise on video input frame.
5779 The filter accepts the following options:
5787 Set noise seed for specific pixel component or all pixel components in case
5788 of @var{all_seed}. Default value is @code{123457}.
5790 @item all_strength, alls
5791 @item c0_strength, c0s
5792 @item c1_strength, c1s
5793 @item c2_strength, c2s
5794 @item c3_strength, c3s
5795 Set noise strength for specific pixel component or all pixel components in case
5796 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
5798 @item all_flags, allf
5803 Set pixel component flags or set flags for all components if @var{all_flags}.
5804 Available values for component flags are:
5807 averaged temporal noise (smoother)
5809 mix random noise with a (semi)regular pattern
5811 temporal noise (noise pattern changes between frames)
5813 uniform noise (gaussian otherwise)
5817 @subsection Examples
5819 Add temporal and uniform noise to input video:
5821 noise=alls=20:allf=t+u
5826 Pass the video source unchanged to the output.
5830 Apply video transform using libopencv.
5832 To enable this filter install libopencv library and headers and
5833 configure FFmpeg with @code{--enable-libopencv}.
5835 This filter accepts the following parameters:
5840 The name of the libopencv filter to apply.
5843 The parameters to pass to the libopencv filter. If not specified the default
5848 Refer to the official libopencv documentation for more precise
5850 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
5852 Follows the list of supported libopencv filters.
5857 Dilate an image by using a specific structuring element.
5858 This filter corresponds to the libopencv function @code{cvDilate}.
5860 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
5862 @var{struct_el} represents a structuring element, and has the syntax:
5863 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
5865 @var{cols} and @var{rows} represent the number of columns and rows of
5866 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
5867 point, and @var{shape} the shape for the structuring element, and
5868 can be one of the values "rect", "cross", "ellipse", "custom".
5870 If the value for @var{shape} is "custom", it must be followed by a
5871 string of the form "=@var{filename}". The file with name
5872 @var{filename} is assumed to represent a binary image, with each
5873 printable character corresponding to a bright pixel. When a custom
5874 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
5875 or columns and rows of the read file are assumed instead.
5877 The default value for @var{struct_el} is "3x3+0x0/rect".
5879 @var{nb_iterations} specifies the number of times the transform is
5880 applied to the image, and defaults to 1.
5882 Follow some example:
5884 # use the default values
5887 # dilate using a structuring element with a 5x5 cross, iterate two times
5888 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
5890 # read the shape from the file diamond.shape, iterate two times
5891 # the file diamond.shape may contain a pattern of characters like this:
5897 # the specified cols and rows are ignored (but not the anchor point coordinates)
5898 ocv=dilate:0x0+2x2/custom=diamond.shape|2
5903 Erode an image by using a specific structuring element.
5904 This filter corresponds to the libopencv function @code{cvErode}.
5906 The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
5907 with the same syntax and semantics as the @ref{dilate} filter.
5911 Smooth the input video.
5913 The filter takes the following parameters:
5914 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
5916 @var{type} is the type of smooth filter to apply, and can be one of
5917 the following values: "blur", "blur_no_scale", "median", "gaussian",
5918 "bilateral". The default value is "gaussian".
5920 @var{param1}, @var{param2}, @var{param3}, and @var{param4} are
5921 parameters whose meanings depend on smooth type. @var{param1} and
5922 @var{param2} accept integer positive values or 0, @var{param3} and
5923 @var{param4} accept float values.
5925 The default value for @var{param1} is 3, the default value for the
5926 other parameters is 0.
5928 These parameters correspond to the parameters assigned to the
5929 libopencv function @code{cvSmooth}.
5934 Overlay one video on top of another.
5936 It takes two inputs and one output, the first input is the "main"
5937 video on which the second input is overlayed.
5939 This filter accepts the following parameters:
5941 A description of the accepted options follows.
5946 Set the expression for the x and y coordinates of the overlayed video
5947 on the main video. Default value is "0" for both expressions. In case
5948 the expression is invalid, it is set to a huge value (meaning that the
5949 overlay will not be displayed within the output visible area).
5952 The action to take when EOF is encountered on the secondary input, accepts one
5953 of the following values:
5957 repeat the last frame (the default)
5961 pass through the main input
5965 Set when the expressions for @option{x}, and @option{y} are evaluated.
5967 It accepts the following values:
5970 only evaluate expressions once during the filter initialization or
5971 when a command is processed
5974 evaluate expressions for each incoming frame
5977 Default value is @samp{frame}.
5980 If set to 1, force the output to terminate when the shortest input
5981 terminates. Default value is 0.
5984 Set the format for the output video.
5986 It accepts the following values:
6001 Default value is @samp{yuv420}.
6003 @item rgb @emph{(deprecated)}
6004 If set to 1, force the filter to accept inputs in the RGB
6005 color space. Default value is 0. This option is deprecated, use
6006 @option{format} instead.
6009 If set to 1, force the filter to draw the last overlay frame over the
6010 main input until the end of the stream. A value of 0 disables this
6011 behavior. Default value is 1.
6014 The @option{x}, and @option{y} expressions can contain the following
6020 main input width and height
6024 overlay input width and height
6028 the computed values for @var{x} and @var{y}. They are evaluated for
6033 horizontal and vertical chroma subsample values of the output
6034 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6038 the number of input frame, starting from 0
6041 the position in the file of the input frame, NAN if unknown
6044 timestamp expressed in seconds, NAN if the input timestamp is unknown
6048 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6049 when evaluation is done @emph{per frame}, and will evaluate to NAN
6050 when @option{eval} is set to @samp{init}.
6052 Be aware that frames are taken from each input video in timestamp
6053 order, hence, if their initial timestamps differ, it is a good idea
6054 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6055 have them begin in the same zero timestamp, as it does the example for
6056 the @var{movie} filter.
6058 You can chain together more overlays but you should test the
6059 efficiency of such approach.
6061 @subsection Commands
6063 This filter supports the following commands:
6067 Modify the x and y of the overlay input.
6068 The command accepts the same syntax of the corresponding option.
6070 If the specified expression is not valid, it is kept at its current
6074 @subsection Examples
6078 Draw the overlay at 10 pixels from the bottom right corner of the main
6081 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6084 Using named options the example above becomes:
6086 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6090 Insert a transparent PNG logo in the bottom left corner of the input,
6091 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6093 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6097 Insert 2 different transparent PNG logos (second logo on bottom
6098 right corner) using the @command{ffmpeg} tool:
6100 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
6104 Add a transparent color layer on top of the main video, @code{WxH}
6105 must specify the size of the main input to the overlay filter:
6107 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6111 Play an original video and a filtered version (here with the deshake
6112 filter) side by side using the @command{ffplay} tool:
6114 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6117 The above command is the same as:
6119 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6123 Make a sliding overlay appearing from the left to the right top part of the
6124 screen starting since time 2:
6126 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6130 Compose output by putting two input videos side to side:
6132 ffmpeg -i left.avi -i right.avi -filter_complex "
6133 nullsrc=size=200x100 [background];
6134 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6135 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6136 [background][left] overlay=shortest=1 [background+left];
6137 [background+left][right] overlay=shortest=1:x=100 [left+right]
6142 mask 10-20 seconds of a video by applying the delogo filter to a section
6144 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6145 -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]'
6150 Chain several overlays in cascade:
6152 nullsrc=s=200x200 [bg];
6153 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6154 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6155 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6156 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6157 [in3] null, [mid2] overlay=100:100 [out0]
6164 Apply Overcomplete Wavelet denoiser.
6166 The filter accepts the following options:
6172 Larger depth values will denoise lower frequency components more, but
6173 slow down filtering.
6175 Must be an int in the range 8-16, default is @code{8}.
6177 @item luma_strength, ls
6180 Must be a double value in the range 0-1000, default is @code{1.0}.
6182 @item chroma_strength, cs
6183 Set chroma strength.
6185 Must be a double value in the range 0-1000, default is @code{1.0}.
6190 Add paddings to the input image, and place the original input at the
6191 given coordinates @var{x}, @var{y}.
6193 This filter accepts the following parameters:
6198 Specify an expression for the size of the output image with the
6199 paddings added. If the value for @var{width} or @var{height} is 0, the
6200 corresponding input size is used for the output.
6202 The @var{width} expression can reference the value set by the
6203 @var{height} expression, and vice versa.
6205 The default value of @var{width} and @var{height} is 0.
6209 Specify an expression for the offsets where to place the input image
6210 in the padded area with respect to the top/left border of the output
6213 The @var{x} expression can reference the value set by the @var{y}
6214 expression, and vice versa.
6216 The default value of @var{x} and @var{y} is 0.
6219 Specify the color of the padded area. For the syntax of this option,
6220 check the "Color" section in the ffmpeg-utils manual.
6222 The default value of @var{color} is "black".
6225 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6226 options are expressions containing the following constants:
6231 the input video width and height
6235 same as @var{in_w} and @var{in_h}
6239 the output width and height, that is the size of the padded area as
6240 specified by the @var{width} and @var{height} expressions
6244 same as @var{out_w} and @var{out_h}
6248 x and y offsets as specified by the @var{x} and @var{y}
6249 expressions, or NAN if not yet specified
6252 same as @var{iw} / @var{ih}
6255 input sample aspect ratio
6258 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6262 horizontal and vertical chroma subsample values. For example for the
6263 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6266 @subsection Examples
6270 Add paddings with color "violet" to the input video. Output video
6271 size is 640x480, the top-left corner of the input video is placed at
6274 pad=640:480:0:40:violet
6277 The example above is equivalent to the following command:
6279 pad=width=640:height=480:x=0:y=40:color=violet
6283 Pad the input to get an output with dimensions increased by 3/2,
6284 and put the input video at the center of the padded area:
6286 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6290 Pad the input to get a squared output with size equal to the maximum
6291 value between the input width and height, and put the input video at
6292 the center of the padded area:
6294 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6298 Pad the input to get a final w/h ratio of 16:9:
6300 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6304 In case of anamorphic video, in order to set the output display aspect
6305 correctly, it is necessary to use @var{sar} in the expression,
6306 according to the relation:
6308 (ih * X / ih) * sar = output_dar
6309 X = output_dar / sar
6312 Thus the previous example needs to be modified to:
6314 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6318 Double output size and put the input video in the bottom-right
6319 corner of the output padded area:
6321 pad="2*iw:2*ih:ow-iw:oh-ih"
6325 @section perspective
6327 Correct perspective of video not recorded perpendicular to the screen.
6329 A description of the accepted parameters follows.
6340 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6341 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6343 The expressions can use the following variables:
6348 the width and height of video frame.
6352 Set interpolation for perspective correction.
6354 It accepts the following values:
6360 Default value is @samp{linear}.
6365 Delay interlaced video by one field time so that the field order changes.
6367 The intended use is to fix PAL movies that have been captured with the
6368 opposite field order to the film-to-video transfer.
6370 A description of the accepted parameters follows.
6376 It accepts the following values:
6379 Capture field order top-first, transfer bottom-first.
6380 Filter will delay the bottom field.
6383 Capture field order bottom-first, transfer top-first.
6384 Filter will delay the top field.
6387 Capture and transfer with the same field order. This mode only exists
6388 for the documentation of the other options to refer to, but if you
6389 actually select it, the filter will faithfully do nothing.
6392 Capture field order determined automatically by field flags, transfer
6394 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6395 basis using field flags. If no field information is available,
6396 then this works just like @samp{u}.
6399 Capture unknown or varying, transfer opposite.
6400 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6401 analyzing the images and selecting the alternative that produces best
6402 match between the fields.
6405 Capture top-first, transfer unknown or varying.
6406 Filter selects among @samp{t} and @samp{p} using image analysis.
6409 Capture bottom-first, transfer unknown or varying.
6410 Filter selects among @samp{b} and @samp{p} using image analysis.
6413 Capture determined by field flags, transfer unknown or varying.
6414 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6415 image analysis. If no field information is available, then this works just
6416 like @samp{U}. This is the default mode.
6419 Both capture and transfer unknown or varying.
6420 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
6424 @section pixdesctest
6426 Pixel format descriptor test filter, mainly useful for internal
6427 testing. The output video should be equal to the input video.
6431 format=monow, pixdesctest
6434 can be used to test the monowhite pixel format descriptor definition.
6438 Enable the specified chain of postprocessing subfilters using libpostproc. This
6439 library should be automatically selected with a GPL build (@code{--enable-gpl}).
6440 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
6441 Each subfilter and some options have a short and a long name that can be used
6442 interchangeably, i.e. dr/dering are the same.
6444 The filters accept the following options:
6448 Set postprocessing subfilters string.
6451 All subfilters share common options to determine their scope:
6455 Honor the quality commands for this subfilter.
6458 Do chrominance filtering, too (default).
6461 Do luminance filtering only (no chrominance).
6464 Do chrominance filtering only (no luminance).
6467 These options can be appended after the subfilter name, separated by a '|'.
6469 Available subfilters are:
6472 @item hb/hdeblock[|difference[|flatness]]
6473 Horizontal deblocking filter
6476 Difference factor where higher values mean more deblocking (default: @code{32}).
6478 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6481 @item vb/vdeblock[|difference[|flatness]]
6482 Vertical deblocking filter
6485 Difference factor where higher values mean more deblocking (default: @code{32}).
6487 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6490 @item ha/hadeblock[|difference[|flatness]]
6491 Accurate horizontal deblocking filter
6494 Difference factor where higher values mean more deblocking (default: @code{32}).
6496 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6499 @item va/vadeblock[|difference[|flatness]]
6500 Accurate vertical deblocking filter
6503 Difference factor where higher values mean more deblocking (default: @code{32}).
6505 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6509 The horizontal and vertical deblocking filters share the difference and
6510 flatness values so you cannot set different horizontal and vertical
6515 Experimental horizontal deblocking filter
6518 Experimental vertical deblocking filter
6523 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
6526 larger -> stronger filtering
6528 larger -> stronger filtering
6530 larger -> stronger filtering
6533 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
6536 Stretch luminance to @code{0-255}.
6539 @item lb/linblenddeint
6540 Linear blend deinterlacing filter that deinterlaces the given block by
6541 filtering all lines with a @code{(1 2 1)} filter.
6543 @item li/linipoldeint
6544 Linear interpolating deinterlacing filter that deinterlaces the given block by
6545 linearly interpolating every second line.
6547 @item ci/cubicipoldeint
6548 Cubic interpolating deinterlacing filter deinterlaces the given block by
6549 cubically interpolating every second line.
6551 @item md/mediandeint
6552 Median deinterlacing filter that deinterlaces the given block by applying a
6553 median filter to every second line.
6555 @item fd/ffmpegdeint
6556 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
6557 second line with a @code{(-1 4 2 4 -1)} filter.
6560 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
6561 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
6563 @item fq/forceQuant[|quantizer]
6564 Overrides the quantizer table from the input with the constant quantizer you
6572 Default pp filter combination (@code{hb|a,vb|a,dr|a})
6575 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
6578 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
6581 @subsection Examples
6585 Apply horizontal and vertical deblocking, deringing and automatic
6586 brightness/contrast:
6592 Apply default filters without brightness/contrast correction:
6598 Apply default filters and temporal denoiser:
6600 pp=default/tmpnoise|1|2|3
6604 Apply deblocking on luminance only, and switch vertical deblocking on or off
6605 automatically depending on available CPU time:
6613 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
6614 Ratio) between two input videos.
6616 This filter takes in input two input videos, the first input is
6617 considered the "main" source and is passed unchanged to the
6618 output. The second input is used as a "reference" video for computing
6621 Both video inputs must have the same resolution and pixel format for
6622 this filter to work correctly. Also it assumes that both inputs
6623 have the same number of frames, which are compared one by one.
6625 The obtained average PSNR is printed through the logging system.
6627 The filter stores the accumulated MSE (mean squared error) of each
6628 frame, and at the end of the processing it is averaged across all frames
6629 equally, and the following formula is applied to obtain the PSNR:
6632 PSNR = 10*log10(MAX^2/MSE)
6635 Where MAX is the average of the maximum values of each component of the
6638 The description of the accepted parameters follows.
6642 If specified the filter will use the named file to save the PSNR of
6643 each individual frame.
6646 The file printed if @var{stats_file} is selected, contains a sequence of
6647 key/value pairs of the form @var{key}:@var{value} for each compared
6650 A description of each shown parameter follows:
6654 sequential number of the input frame, starting from 1
6657 Mean Square Error pixel-by-pixel average difference of the compared
6658 frames, averaged over all the image components.
6660 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
6661 Mean Square Error pixel-by-pixel average difference of the compared
6662 frames for the component specified by the suffix.
6664 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
6665 Peak Signal to Noise ratio of the compared frames for the component
6666 specified by the suffix.
6671 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
6672 [main][ref] psnr="stats_file=stats.log" [out]
6675 On this example the input file being processed is compared with the
6676 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
6677 is stored in @file{stats.log}.
6682 Pulldown reversal (inverse telecine) filter, capable of handling mixed
6683 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
6686 The pullup filter is designed to take advantage of future context in making
6687 its decisions. This filter is stateless in the sense that it does not lock
6688 onto a pattern to follow, but it instead looks forward to the following
6689 fields in order to identify matches and rebuild progressive frames.
6691 To produce content with an even framerate, insert the fps filter after
6692 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
6693 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
6695 The filter accepts the following options:
6702 These options set the amount of "junk" to ignore at the left, right, top, and
6703 bottom of the image, respectively. Left and right are in units of 8 pixels,
6704 while top and bottom are in units of 2 lines.
6705 The default is 8 pixels on each side.
6708 Set the strict breaks. Setting this option to 1 will reduce the chances of
6709 filter generating an occasional mismatched frame, but it may also cause an
6710 excessive number of frames to be dropped during high motion sequences.
6711 Conversely, setting it to -1 will make filter match fields more easily.
6712 This may help processing of video where there is slight blurring between
6713 the fields, but may also cause there to be interlaced frames in the output.
6714 Default value is @code{0}.
6717 Set the metric plane to use. It accepts the following values:
6723 Use chroma blue plane.
6726 Use chroma red plane.
6729 This option may be set to use chroma plane instead of the default luma plane
6730 for doing filter's computations. This may improve accuracy on very clean
6731 source material, but more likely will decrease accuracy, especially if there
6732 is chroma noise (rainbow effect) or any grayscale video.
6733 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
6734 load and make pullup usable in realtime on slow machines.
6737 For best results (without duplicated frames in the output file) it is
6738 necessary to change the output frame rate. For example, to inverse
6739 telecine NTSC input:
6741 ffmpeg -i input -vf pullup -r 24000/1001 ...
6746 Suppress a TV station logo, using an image file to determine which
6747 pixels comprise the logo. It works by filling in the pixels that
6748 comprise the logo with neighboring pixels.
6750 The filter accepts the following options:
6754 Set the filter bitmap file, which can be any image format supported by
6755 libavformat. The width and height of the image file must match those of the
6756 video stream being processed.
6759 Pixels in the provided bitmap image with a value of zero are not
6760 considered part of the logo, non-zero pixels are considered part of
6761 the logo. If you use white (255) for the logo and black (0) for the
6762 rest, you will be safe. For making the filter bitmap, it is
6763 recommended to take a screen capture of a black frame with the logo
6764 visible, and then using a threshold filter followed by the erode
6765 filter once or twice.
6767 If needed, little splotches can be fixed manually. Remember that if
6768 logo pixels are not covered, the filter quality will be much
6769 reduced. Marking too many pixels as part of the logo does not hurt as
6770 much, but it will increase the amount of blurring needed to cover over
6771 the image and will destroy more information than necessary, and extra
6772 pixels will slow things down on a large logo.
6776 Rotate video by an arbitrary angle expressed in radians.
6778 The filter accepts the following options:
6780 A description of the optional parameters follows.
6783 Set an expression for the angle by which to rotate the input video
6784 clockwise, expressed as a number of radians. A negative value will
6785 result in a counter-clockwise rotation. By default it is set to "0".
6787 This expression is evaluated for each frame.
6790 Set the output width expression, default value is "iw".
6791 This expression is evaluated just once during configuration.
6794 Set the output height expression, default value is "ih".
6795 This expression is evaluated just once during configuration.
6798 Enable bilinear interpolation if set to 1, a value of 0 disables
6799 it. Default value is 1.
6802 Set the color used to fill the output area not covered by the rotated
6803 image. For the generalsyntax of this option, check the "Color" section in the
6804 ffmpeg-utils manual. If the special value "none" is selected then no
6805 background is printed (useful for example if the background is never shown).
6807 Default value is "black".
6810 The expressions for the angle and the output size can contain the
6811 following constants and functions:
6815 sequential number of the input frame, starting from 0. It is always NAN
6816 before the first frame is filtered.
6819 time in seconds of the input frame, it is set to 0 when the filter is
6820 configured. It is always NAN before the first frame is filtered.
6824 horizontal and vertical chroma subsample values. For example for the
6825 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6829 the input video width and height
6833 the output width and height, that is the size of the padded area as
6834 specified by the @var{width} and @var{height} expressions
6838 the minimal width/height required for completely containing the input
6839 video rotated by @var{a} radians.
6841 These are only available when computing the @option{out_w} and
6842 @option{out_h} expressions.
6845 @subsection Examples
6849 Rotate the input by PI/6 radians clockwise:
6855 Rotate the input by PI/6 radians counter-clockwise:
6861 Rotate the input by 45 degrees clockwise:
6867 Apply a constant rotation with period T, starting from an angle of PI/3:
6869 rotate=PI/3+2*PI*t/T
6873 Make the input video rotation oscillating with a period of T
6874 seconds and an amplitude of A radians:
6876 rotate=A*sin(2*PI/T*t)
6880 Rotate the video, output size is chosen so that the whole rotating
6881 input video is always completely contained in the output:
6883 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
6887 Rotate the video, reduce the output size so that no background is ever
6890 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
6894 @subsection Commands
6896 The filter supports the following commands:
6900 Set the angle expression.
6901 The command accepts the same syntax of the corresponding option.
6903 If the specified expression is not valid, it is kept at its current
6909 Apply Shape Adaptive Blur.
6911 The filter accepts the following options:
6914 @item luma_radius, lr
6915 Set luma blur filter strength, must be a value in range 0.1-4.0, default
6916 value is 1.0. A greater value will result in a more blurred image, and
6917 in slower processing.
6919 @item luma_pre_filter_radius, lpfr
6920 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
6923 @item luma_strength, ls
6924 Set luma maximum difference between pixels to still be considered, must
6925 be a value in the 0.1-100.0 range, default value is 1.0.
6927 @item chroma_radius, cr
6928 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
6929 greater value will result in a more blurred image, and in slower
6932 @item chroma_pre_filter_radius, cpfr
6933 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
6935 @item chroma_strength, cs
6936 Set chroma maximum difference between pixels to still be considered,
6937 must be a value in the 0.1-100.0 range.
6940 Each chroma option value, if not explicitly specified, is set to the
6941 corresponding luma option value.
6946 Scale (resize) the input video, using the libswscale library.
6948 The scale filter forces the output display aspect ratio to be the same
6949 of the input, by changing the output sample aspect ratio.
6951 If the input image format is different from the format requested by
6952 the next filter, the scale filter will convert the input to the
6956 The filter accepts the following options, or any of the options
6957 supported by the libswscale scaler.
6959 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
6960 the complete list of scaler options.
6965 Set the output video dimension expression. Default value is the input
6968 If the value is 0, the input width is used for the output.
6970 If one of the values is -1, the scale filter will use a value that
6971 maintains the aspect ratio of the input image, calculated from the
6972 other specified dimension. If both of them are -1, the input size is
6975 If one of the values is -n with n > 1, the scale filter will also use a value
6976 that maintains the aspect ratio of the input image, calculated from the other
6977 specified dimension. After that it will, however, make sure that the calculated
6978 dimension is divisible by n and adjust the value if necessary.
6980 See below for the list of accepted constants for use in the dimension
6984 Set the interlacing mode. It accepts the following values:
6988 Force interlaced aware scaling.
6991 Do not apply interlaced scaling.
6994 Select interlaced aware scaling depending on whether the source frames
6995 are flagged as interlaced or not.
6998 Default value is @samp{0}.
7001 Set libswscale scaling flags. See
7002 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7003 complete list of values. If not explicitly specified the filter applies
7007 Set the video size. For the syntax of this option, check the "Video size"
7008 section in the ffmpeg-utils manual.
7010 @item in_color_matrix
7011 @item out_color_matrix
7012 Set in/output YCbCr color space type.
7014 This allows the autodetected value to be overridden as well as allows forcing
7015 a specific value used for the output and encoder.
7017 If not specified, the color space type depends on the pixel format.
7023 Choose automatically.
7026 Format conforming to International Telecommunication Union (ITU)
7027 Recommendation BT.709.
7030 Set color space conforming to the United States Federal Communications
7031 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7034 Set color space conforming to:
7038 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7041 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7044 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7049 Set color space conforming to SMPTE ST 240:1999.
7054 Set in/output YCbCr sample range.
7056 This allows the autodetected value to be overridden as well as allows forcing
7057 a specific value used for the output and encoder. If not specified, the
7058 range depends on the pixel format. Possible values:
7062 Choose automatically.
7065 Set full range (0-255 in case of 8-bit luma).
7068 Set "MPEG" range (16-235 in case of 8-bit luma).
7071 @item force_original_aspect_ratio
7072 Enable decreasing or increasing output video width or height if necessary to
7073 keep the original aspect ratio. Possible values:
7077 Scale the video as specified and disable this feature.
7080 The output video dimensions will automatically be decreased if needed.
7083 The output video dimensions will automatically be increased if needed.
7087 One useful instance of this option is that when you know a specific device's
7088 maximum allowed resolution, you can use this to limit the output video to
7089 that, while retaining the aspect ratio. For example, device A allows
7090 1280x720 playback, and your video is 1920x800. Using this option (set it to
7091 decrease) and specifying 1280x720 to the command line makes the output
7094 Please note that this is a different thing than specifying -1 for @option{w}
7095 or @option{h}, you still need to specify the output resolution for this option
7100 The values of the @option{w} and @option{h} options are expressions
7101 containing the following constants:
7106 the input width and height
7110 same as @var{in_w} and @var{in_h}
7114 the output (scaled) width and height
7118 same as @var{out_w} and @var{out_h}
7121 same as @var{iw} / @var{ih}
7124 input sample aspect ratio
7127 input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7131 horizontal and vertical input chroma subsample values. For example for the
7132 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7136 horizontal and vertical output chroma subsample values. For example for the
7137 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7140 @subsection Examples
7144 Scale the input video to a size of 200x100:
7149 This is equivalent to:
7160 Specify a size abbreviation for the output size:
7165 which can also be written as:
7171 Scale the input to 2x:
7177 The above is the same as:
7183 Scale the input to 2x with forced interlaced scaling:
7185 scale=2*iw:2*ih:interl=1
7189 Scale the input to half size:
7195 Increase the width, and set the height to the same size:
7201 Seek for Greek harmony:
7208 Increase the height, and set the width to 3/2 of the height:
7210 scale=w=3/2*oh:h=3/5*ih
7214 Increase the size, but make the size a multiple of the chroma
7217 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7221 Increase the width to a maximum of 500 pixels, keep the same input
7224 scale=w='min(500\, iw*3/2):h=-1'
7228 @section separatefields
7230 The @code{separatefields} takes a frame-based video input and splits
7231 each frame into its components fields, producing a new half height clip
7232 with twice the frame rate and twice the frame count.
7234 This filter use field-dominance information in frame to decide which
7235 of each pair of fields to place first in the output.
7236 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7238 @section setdar, setsar
7240 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7243 This is done by changing the specified Sample (aka Pixel) Aspect
7244 Ratio, according to the following equation:
7246 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7249 Keep in mind that the @code{setdar} filter does not modify the pixel
7250 dimensions of the video frame. Also the display aspect ratio set by
7251 this filter may be changed by later filters in the filterchain,
7252 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7255 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7256 the filter output video.
7258 Note that as a consequence of the application of this filter, the
7259 output display aspect ratio will change according to the equation
7262 Keep in mind that the sample aspect ratio set by the @code{setsar}
7263 filter may be changed by later filters in the filterchain, e.g. if
7264 another "setsar" or a "setdar" filter is applied.
7266 The filters accept the following options:
7269 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7270 Set the aspect ratio used by the filter.
7272 The parameter can be a floating point number string, an expression, or
7273 a string of the form @var{num}:@var{den}, where @var{num} and
7274 @var{den} are the numerator and denominator of the aspect ratio. If
7275 the parameter is not specified, it is assumed the value "0".
7276 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7280 Set the maximum integer value to use for expressing numerator and
7281 denominator when reducing the expressed aspect ratio to a rational.
7282 Default value is @code{100}.
7286 The parameter @var{sar} is an expression containing
7287 the following constants:
7291 the corresponding mathematical approximated values for e
7292 (euler number), pi (greek PI), phi (golden ratio)
7295 the input width and height
7298 same as @var{w} / @var{h}
7301 input sample aspect ratio
7304 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
7307 horizontal and vertical chroma subsample values. For example for the
7308 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7311 @subsection Examples
7316 To change the display aspect ratio to 16:9, specify one of the following:
7324 To change the sample aspect ratio to 10:11, specify:
7330 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7331 1000 in the aspect ratio reduction, use the command:
7333 setdar=ratio=16/9:max=1000
7341 Force field for the output video frame.
7343 The @code{setfield} filter marks the interlace type field for the
7344 output frames. It does not change the input frame, but only sets the
7345 corresponding property, which affects how the frame is treated by
7346 following filters (e.g. @code{fieldorder} or @code{yadif}).
7348 The filter accepts the following options:
7353 Available values are:
7357 Keep the same field property.
7360 Mark the frame as bottom-field-first.
7363 Mark the frame as top-field-first.
7366 Mark the frame as progressive.
7372 Show a line containing various information for each input video frame.
7373 The input video is not modified.
7375 The shown line contains a sequence of key/value pairs of the form
7376 @var{key}:@var{value}.
7378 A description of each shown parameter follows:
7382 sequential number of the input frame, starting from 0
7385 Presentation TimeStamp of the input frame, expressed as a number of
7386 time base units. The time base unit depends on the filter input pad.
7389 Presentation TimeStamp of the input frame, expressed as a number of
7393 position of the frame in the input stream, -1 if this information in
7394 unavailable and/or meaningless (for example in case of synthetic video)
7400 sample aspect ratio of the input frame, expressed in the form
7404 size of the input frame. For the syntax of this option, check the "Video size"
7405 section in the ffmpeg-utils manual.
7408 interlaced mode ("P" for "progressive", "T" for top field first, "B"
7409 for bottom field first)
7412 1 if the frame is a key frame, 0 otherwise
7415 picture type of the input frame ("I" for an I-frame, "P" for a
7416 P-frame, "B" for a B-frame, "?" for unknown type).
7417 Check also the documentation of the @code{AVPictureType} enum and of
7418 the @code{av_get_picture_type_char} function defined in
7419 @file{libavutil/avutil.h}.
7422 Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame
7424 @item plane_checksum
7425 Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
7426 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]"
7429 @section shuffleplanes
7431 Reorder and/or duplicate video planes.
7433 This filter accepts the following options:
7438 The index of the input plane to be used as the first output plane.
7441 The index of the input plane to be used as the second output plane.
7444 The index of the input plane to be used as the third output plane.
7447 The index of the input plane to be used as the fourth output plane.
7451 The first plane has the index 0. The default is to keep the input unchanged.
7455 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
7457 swaps the second and third planes of the input.
7462 Blur the input video without impacting the outlines.
7464 The filter accepts the following options:
7467 @item luma_radius, lr
7468 Set the luma radius. The option value must be a float number in
7469 the range [0.1,5.0] that specifies the variance of the gaussian filter
7470 used to blur the image (slower if larger). Default value is 1.0.
7472 @item luma_strength, ls
7473 Set the luma strength. The option value must be a float number
7474 in the range [-1.0,1.0] that configures the blurring. A value included
7475 in [0.0,1.0] will blur the image whereas a value included in
7476 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7478 @item luma_threshold, lt
7479 Set the luma threshold used as a coefficient to determine
7480 whether a pixel should be blurred or not. The option value must be an
7481 integer in the range [-30,30]. A value of 0 will filter all the image,
7482 a value included in [0,30] will filter flat areas and a value included
7483 in [-30,0] will filter edges. Default value is 0.
7485 @item chroma_radius, cr
7486 Set the chroma radius. The option value must be a float number in
7487 the range [0.1,5.0] that specifies the variance of the gaussian filter
7488 used to blur the image (slower if larger). Default value is 1.0.
7490 @item chroma_strength, cs
7491 Set the chroma strength. The option value must be a float number
7492 in the range [-1.0,1.0] that configures the blurring. A value included
7493 in [0.0,1.0] will blur the image whereas a value included in
7494 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7496 @item chroma_threshold, ct
7497 Set the chroma threshold used as a coefficient to determine
7498 whether a pixel should be blurred or not. The option value must be an
7499 integer in the range [-30,30]. A value of 0 will filter all the image,
7500 a value included in [0,30] will filter flat areas and a value included
7501 in [-30,0] will filter edges. Default value is 0.
7504 If a chroma option is not explicitly set, the corresponding luma value
7509 Convert between different stereoscopic image formats.
7511 The filters accept the following options:
7515 Set stereoscopic image format of input.
7517 Available values for input image formats are:
7520 side by side parallel (left eye left, right eye right)
7523 side by side crosseye (right eye left, left eye right)
7526 side by side parallel with half width resolution
7527 (left eye left, right eye right)
7530 side by side crosseye with half width resolution
7531 (right eye left, left eye right)
7534 above-below (left eye above, right eye below)
7537 above-below (right eye above, left eye below)
7540 above-below with half height resolution
7541 (left eye above, right eye below)
7544 above-below with half height resolution
7545 (right eye above, left eye below)
7548 alternating frames (left eye first, right eye second)
7551 alternating frames (right eye first, left eye second)
7553 Default value is @samp{sbsl}.
7557 Set stereoscopic image format of output.
7559 Available values for output image formats are all the input formats as well as:
7562 anaglyph red/blue gray
7563 (red filter on left eye, blue filter on right eye)
7566 anaglyph red/green gray
7567 (red filter on left eye, green filter on right eye)
7570 anaglyph red/cyan gray
7571 (red filter on left eye, cyan filter on right eye)
7574 anaglyph red/cyan half colored
7575 (red filter on left eye, cyan filter on right eye)
7578 anaglyph red/cyan color
7579 (red filter on left eye, cyan filter on right eye)
7582 anaglyph red/cyan color optimized with the least squares projection of dubois
7583 (red filter on left eye, cyan filter on right eye)
7586 anaglyph green/magenta gray
7587 (green filter on left eye, magenta filter on right eye)
7590 anaglyph green/magenta half colored
7591 (green filter on left eye, magenta filter on right eye)
7594 anaglyph green/magenta colored
7595 (green filter on left eye, magenta filter on right eye)
7598 anaglyph green/magenta color optimized with the least squares projection of dubois
7599 (green filter on left eye, magenta filter on right eye)
7602 anaglyph yellow/blue gray
7603 (yellow filter on left eye, blue filter on right eye)
7606 anaglyph yellow/blue half colored
7607 (yellow filter on left eye, blue filter on right eye)
7610 anaglyph yellow/blue colored
7611 (yellow filter on left eye, blue filter on right eye)
7614 anaglyph yellow/blue color optimized with the least squares projection of dubois
7615 (yellow filter on left eye, blue filter on right eye)
7618 interleaved rows (left eye has top row, right eye starts on next row)
7621 interleaved rows (right eye has top row, left eye starts on next row)
7624 mono output (left eye only)
7627 mono output (right eye only)
7630 Default value is @samp{arcd}.
7633 @subsection Examples
7637 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
7643 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
7651 Apply a simple postprocessing filter that compresses and decompresses the image
7652 at several (or - in the case of @option{quality} level @code{6} - all) shifts
7653 and average the results.
7655 The filter accepts the following options:
7659 Set quality. This option defines the number of levels for averaging. It accepts
7660 an integer in the range 0-6. If set to @code{0}, the filter will have no
7661 effect. A value of @code{6} means the higher quality. For each increment of
7662 that value the speed drops by a factor of approximately 2. Default value is
7666 Force a constant quantization parameter. If not set, the filter will use the QP
7667 from the video stream (if available).
7670 Set thresholding mode. Available modes are:
7674 Set hard thresholding (default).
7676 Set soft thresholding (better de-ringing effect, but likely blurrier).
7680 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
7681 option may cause flicker since the B-Frames have often larger QP. Default is
7682 @code{0} (not enabled).
7688 Draw subtitles on top of input video using the libass library.
7690 To enable compilation of this filter you need to configure FFmpeg with
7691 @code{--enable-libass}. This filter also requires a build with libavcodec and
7692 libavformat to convert the passed subtitles file to ASS (Advanced Substation
7693 Alpha) subtitles format.
7695 The filter accepts the following options:
7699 Set the filename of the subtitle file to read. It must be specified.
7702 Specify the size of the original video, the video for which the ASS file
7703 was composed. For the syntax of this option, check the "Video size" section in
7704 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
7705 this is necessary to correctly scale the fonts if the aspect ratio has been
7709 Set subtitles input character encoding. @code{subtitles} filter only. Only
7710 useful if not UTF-8.
7713 If the first key is not specified, it is assumed that the first value
7714 specifies the @option{filename}.
7716 For example, to render the file @file{sub.srt} on top of the input
7717 video, use the command:
7722 which is equivalent to:
7724 subtitles=filename=sub.srt
7729 Scale the input by 2x and smooth using the Super2xSaI (Scale and
7730 Interpolate) pixel art scaling algorithm.
7732 Useful for enlarging pixel art images without reducing sharpness.
7739 Apply telecine process to the video.
7741 This filter accepts the following options:
7750 The default value is @code{top}.
7754 A string of numbers representing the pulldown pattern you wish to apply.
7755 The default value is @code{23}.
7759 Some typical patterns:
7764 24p: 2332 (preferred)
7771 24p: 222222222223 ("Euro pulldown")
7777 Select the most representative frame in a given sequence of consecutive frames.
7779 The filter accepts the following options:
7783 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
7784 will pick one of them, and then handle the next batch of @var{n} frames until
7785 the end. Default is @code{100}.
7788 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
7789 value will result in a higher memory usage, so a high value is not recommended.
7791 @subsection Examples
7795 Extract one picture each 50 frames:
7801 Complete example of a thumbnail creation with @command{ffmpeg}:
7803 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
7809 Tile several successive frames together.
7811 The filter accepts the following options:
7816 Set the grid size (i.e. the number of lines and columns). For the syntax of
7817 this option, check the "Video size" section in the ffmpeg-utils manual.
7820 Set the maximum number of frames to render in the given area. It must be less
7821 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
7822 the area will be used.
7825 Set the outer border margin in pixels.
7828 Set the inner border thickness (i.e. the number of pixels between frames). For
7829 more advanced padding options (such as having different values for the edges),
7830 refer to the pad video filter.
7833 Specify the color of the unused areaFor the syntax of this option, check the
7834 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
7838 @subsection Examples
7842 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
7844 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
7846 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
7847 duplicating each output frame to accommodate the originally detected frame
7851 Display @code{5} pictures in an area of @code{3x2} frames,
7852 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
7853 mixed flat and named options:
7855 tile=3x2:nb_frames=5:padding=7:margin=2
7861 Perform various types of temporal field interlacing.
7863 Frames are counted starting from 1, so the first input frame is
7866 The filter accepts the following options:
7871 Specify the mode of the interlacing. This option can also be specified
7872 as a value alone. See below for a list of values for this option.
7874 Available values are:
7878 Move odd frames into the upper field, even into the lower field,
7879 generating a double height frame at half frame rate.
7882 Only output even frames, odd frames are dropped, generating a frame with
7883 unchanged height at half frame rate.
7886 Only output odd frames, even frames are dropped, generating a frame with
7887 unchanged height at half frame rate.
7890 Expand each frame to full height, but pad alternate lines with black,
7891 generating a frame with double height at the same input frame rate.
7893 @item interleave_top, 4
7894 Interleave the upper field from odd frames with the lower field from
7895 even frames, generating a frame with unchanged height at half frame rate.
7897 @item interleave_bottom, 5
7898 Interleave the lower field from odd frames with the upper field from
7899 even frames, generating a frame with unchanged height at half frame rate.
7901 @item interlacex2, 6
7902 Double frame rate with unchanged height. Frames are inserted each
7903 containing the second temporal field from the previous input frame and
7904 the first temporal field from the next input frame. This mode relies on
7905 the top_field_first flag. Useful for interlaced video displays with no
7906 field synchronisation.
7909 Numeric values are deprecated but are accepted for backward
7910 compatibility reasons.
7912 Default mode is @code{merge}.
7915 Specify flags influencing the filter process.
7917 Available value for @var{flags} is:
7920 @item low_pass_filter, vlfp
7921 Enable vertical low-pass filtering in the filter.
7922 Vertical low-pass filtering is required when creating an interlaced
7923 destination from a progressive source which contains high-frequency
7924 vertical detail. Filtering will reduce interlace 'twitter' and Moire
7927 Vertical low-pass filtering can only be enabled for @option{mode}
7928 @var{interleave_top} and @var{interleave_bottom}.
7935 Transpose rows with columns in the input video and optionally flip it.
7937 This filter accepts the following options:
7942 Specify the transposition direction.
7944 Can assume the following values:
7946 @item 0, 4, cclock_flip
7947 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
7955 Rotate by 90 degrees clockwise, that is:
7963 Rotate by 90 degrees counterclockwise, that is:
7970 @item 3, 7, clock_flip
7971 Rotate by 90 degrees clockwise and vertically flip, that is:
7979 For values between 4-7, the transposition is only done if the input
7980 video geometry is portrait and not landscape. These values are
7981 deprecated, the @code{passthrough} option should be used instead.
7983 Numerical values are deprecated, and should be dropped in favor of
7987 Do not apply the transposition if the input geometry matches the one
7988 specified by the specified value. It accepts the following values:
7991 Always apply transposition.
7993 Preserve portrait geometry (when @var{height} >= @var{width}).
7995 Preserve landscape geometry (when @var{width} >= @var{height}).
7998 Default value is @code{none}.
8001 For example to rotate by 90 degrees clockwise and preserve portrait
8004 transpose=dir=1:passthrough=portrait
8007 The command above can also be specified as:
8009 transpose=1:portrait
8013 Trim the input so that the output contains one continuous subpart of the input.
8015 This filter accepts the following options:
8018 Specify time of the start of the kept section, i.e. the frame with the
8019 timestamp @var{start} will be the first frame in the output.
8022 Specify time of the first frame that will be dropped, i.e. the frame
8023 immediately preceding the one with the timestamp @var{end} will be the last
8024 frame in the output.
8027 Same as @var{start}, except this option sets the start timestamp in timebase
8028 units instead of seconds.
8031 Same as @var{end}, except this option sets the end timestamp in timebase units
8035 Specify maximum duration of the output.
8038 Number of the first frame that should be passed to output.
8041 Number of the first frame that should be dropped.
8044 @option{start}, @option{end}, @option{duration} are expressed as time
8045 duration specifications, check the "Time duration" section in the
8046 ffmpeg-utils manual.
8048 Note that the first two sets of the start/end options and the @option{duration}
8049 option look at the frame timestamp, while the _frame variants simply count the
8050 frames that pass through the filter. Also note that this filter does not modify
8051 the timestamps. If you wish that the output timestamps start at zero, insert a
8052 setpts filter after the trim filter.
8054 If multiple start or end options are set, this filter tries to be greedy and
8055 keep all the frames that match at least one of the specified constraints. To keep
8056 only the part that matches all the constraints at once, chain multiple trim
8059 The defaults are such that all the input is kept. So it is possible to set e.g.
8060 just the end values to keep everything before the specified time.
8065 drop everything except the second minute of input
8067 ffmpeg -i INPUT -vf trim=60:120
8071 keep only the first second
8073 ffmpeg -i INPUT -vf trim=duration=1
8081 Sharpen or blur the input video.
8083 It accepts the following parameters:
8086 @item luma_msize_x, lx
8087 Set the luma matrix horizontal size. It must be an odd integer between
8088 3 and 63, default value is 5.
8090 @item luma_msize_y, ly
8091 Set the luma matrix vertical size. It must be an odd integer between 3
8092 and 63, default value is 5.
8094 @item luma_amount, la
8095 Set the luma 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 1.0.
8103 @item chroma_msize_x, cx
8104 Set the chroma matrix horizontal size. It must be an odd integer
8105 between 3 and 63, default value is 5.
8107 @item chroma_msize_y, cy
8108 Set the chroma matrix vertical size. It must be an odd integer
8109 between 3 and 63, default value is 5.
8111 @item chroma_amount, ca
8112 Set the chroma effect strength. It can be a float number, reasonable
8113 values lay between -1.5 and 1.5.
8115 Negative values will blur the input video, while positive values will
8116 sharpen it, a value of zero will disable the effect.
8118 Default value is 0.0.
8121 If set to 1, specify using OpenCL capabilities, only available if
8122 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
8126 All parameters are optional and default to the equivalent of the
8127 string '5:5:1.0:5:5:0.0'.
8129 @subsection Examples
8133 Apply strong luma sharpen effect:
8135 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
8139 Apply strong blur of both luma and chroma parameters:
8141 unsharp=7:7:-2:7:7:-2
8145 @anchor{vidstabdetect}
8146 @section vidstabdetect
8148 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
8149 @ref{vidstabtransform} for pass 2.
8151 This filter generates a file with relative translation and rotation
8152 transform information about subsequent frames, which is then used by
8153 the @ref{vidstabtransform} filter.
8155 To enable compilation of this filter you need to configure FFmpeg with
8156 @code{--enable-libvidstab}.
8158 This filter accepts the following options:
8162 Set the path to the file used to write the transforms information.
8163 Default value is @file{transforms.trf}.
8166 Set how shaky the video is and how quick the camera is. It accepts an
8167 integer in the range 1-10, a value of 1 means little shakiness, a
8168 value of 10 means strong shakiness. Default value is 5.
8171 Set the accuracy of the detection process. It must be a value in the
8172 range 1-15. A value of 1 means low accuracy, a value of 15 means high
8173 accuracy. Default value is 15.
8176 Set stepsize of the search process. The region around minimum is
8177 scanned with 1 pixel resolution. Default value is 6.
8180 Set minimum contrast. Below this value a local measurement field is
8181 discarded. Must be a floating point value in the range 0-1. Default
8185 Set reference frame number for tripod mode.
8187 If enabled, the motion of the frames is compared to a reference frame
8188 in the filtered stream, identified by the specified number. The idea
8189 is to compensate all movements in a more-or-less static scene and keep
8190 the camera view absolutely still.
8192 If set to 0, it is disabled. The frames are counted starting from 1.
8195 Show fields and transforms in the resulting frames. It accepts an
8196 integer in the range 0-2. Default value is 0, which disables any
8200 @subsection Examples
8210 Analyze strongly shaky movie and put the results in file
8211 @file{mytransforms.trf}:
8213 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
8217 Visualize the result of internal transformations in the resulting
8220 vidstabdetect=show=1
8224 Analyze a video with medium shakiness using @command{ffmpeg}:
8226 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
8230 @anchor{vidstabtransform}
8231 @section vidstabtransform
8233 Video stabilization/deshaking: pass 2 of 2,
8234 see @ref{vidstabdetect} for pass 1.
8236 Read a file with transform information for each frame and
8237 apply/compensate them. Together with the @ref{vidstabdetect}
8238 filter this can be used to deshake videos. See also
8239 @url{http://public.hronopik.de/vid.stab}. It is important to also use
8240 the unsharp filter, see below.
8242 To enable compilation of this filter you need to configure FFmpeg with
8243 @code{--enable-libvidstab}.
8249 Set path to the file used to read the transforms. Default value is
8250 @file{transforms.trf}).
8253 Set the number of frames (value*2 + 1) used for lowpass filtering the
8254 camera movements. Default value is 10.
8256 For example a number of 10 means that 21 frames are used (10 in the
8257 past and 10 in the future) to smoothen the motion in the video. A
8258 larger values leads to a smoother video, but limits the acceleration
8259 of the camera (pan/tilt movements). 0 is a special case where a
8260 static camera is simulated.
8263 Set the camera path optimization algorithm.
8265 Accepted values are:
8268 gaussian kernel low-pass filter on camera motion (default)
8270 averaging on transformations
8274 Set maximal number of pixels to translate frames. Default value is -1,
8278 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
8279 value is -1, meaning no limit.
8282 Specify how to deal with borders that may be visible due to movement
8285 Available values are:
8288 keep image information from previous frame (default)
8290 fill the border black
8294 Invert transforms if set to 1. Default value is 0.
8297 Consider transforms as relative to previsou frame if set to 1,
8298 absolute if set to 0. Default value is 0.
8301 Set percentage to zoom. A positive value will result in a zoom-in
8302 effect, a negative value in a zoom-out effect. Default value is 0 (no
8306 Set optimal zooming to avoid borders.
8308 Accepted values are:
8313 optimal static zoom value is determined (only very strong movements
8314 will lead to visible borders) (default)
8316 optimal adaptive zoom value is determined (no borders will be
8317 visible), see @option{zoomspeed}
8320 Note that the value given at zoom is added to the one calculated here.
8323 Set percent to zoom maximally each frame (enabled when
8324 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
8328 Specify type of interpolation.
8330 Available values are:
8335 linear only horizontal
8337 linear in both directions (default)
8339 cubic in both directions (slow)
8343 Enable virtual tripod mode if set to 1, which is equivalent to
8344 @code{relative=0:smoothing=0}. Default value is 0.
8346 Use also @code{tripod} option of @ref{vidstabdetect}.
8349 Increase log verbosity if set to 1. Also the detected global motions
8350 are written to the temporary file @file{global_motions.trf}. Default
8354 @subsection Examples
8358 Use @command{ffmpeg} for a typical stabilization with default values:
8360 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
8363 Note the use of the unsharp filter which is always recommended.
8366 Zoom in a bit more and load transform data from a given file:
8368 vidstabtransform=zoom=5:input="mytransforms.trf"
8372 Smoothen the video even more:
8374 vidstabtransform=smoothing=30
8380 Flip the input video vertically.
8382 For example, to vertically flip a video with @command{ffmpeg}:
8384 ffmpeg -i in.avi -vf "vflip" out.avi
8389 Make or reverse a natural vignetting effect.
8391 The filter accepts the following options:
8395 Set lens angle expression as a number of radians.
8397 The value is clipped in the @code{[0,PI/2]} range.
8399 Default value: @code{"PI/5"}
8403 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
8407 Set forward/backward mode.
8409 Available modes are:
8412 The larger the distance from the central point, the darker the image becomes.
8415 The larger the distance from the central point, the brighter the image becomes.
8416 This can be used to reverse a vignette effect, though there is no automatic
8417 detection to extract the lens @option{angle} and other settings (yet). It can
8418 also be used to create a burning effect.
8421 Default value is @samp{forward}.
8424 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
8426 It accepts the following values:
8429 Evaluate expressions only once during the filter initialization.
8432 Evaluate expressions for each incoming frame. This is way slower than the
8433 @samp{init} mode since it requires all the scalers to be re-computed, but it
8434 allows advanced dynamic expressions.
8437 Default value is @samp{init}.
8440 Set dithering to reduce the circular banding effects. Default is @code{1}
8444 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
8445 Setting this value to the SAR of the input will make a rectangular vignetting
8446 following the dimensions of the video.
8448 Default is @code{1/1}.
8451 @subsection Expressions
8453 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
8454 following parameters.
8459 input width and height
8462 the number of input frame, starting from 0
8465 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
8466 @var{TB} units, NAN if undefined
8469 frame rate of the input video, NAN if the input frame rate is unknown
8472 the PTS (Presentation TimeStamp) of the filtered video frame,
8473 expressed in seconds, NAN if undefined
8476 time base of the input video
8480 @subsection Examples
8484 Apply simple strong vignetting effect:
8490 Make a flickering vignetting:
8492 vignette='PI/4+random(1)*PI/50':eval=frame
8499 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
8500 Deinterlacing Filter").
8502 Based on the process described by Martin Weston for BBC R&D, and
8503 implemented based on the de-interlace algorithm written by Jim
8504 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
8505 uses filter coefficients calculated by BBC R&D.
8507 There are two sets of filter coefficients, so called "simple":
8508 and "complex". Which set of filter coefficients is used can
8509 be set by passing an optional parameter:
8513 Set the interlacing filter coefficients. Accepts one of the following values:
8517 Simple filter coefficient set.
8519 More-complex filter coefficient set.
8521 Default value is @samp{complex}.
8524 Specify which frames to deinterlace. Accept one of the following values:
8528 Deinterlace all frames,
8530 Only deinterlace frames marked as interlaced.
8533 Default value is @samp{all}.
8539 Deinterlace the input video ("yadif" means "yet another deinterlacing
8542 This filter accepts the following options:
8548 The interlacing mode to adopt, accepts one of the following values:
8552 output 1 frame for each frame
8554 output 1 frame for each field
8555 @item 2, send_frame_nospatial
8556 like @code{send_frame} but skip spatial interlacing check
8557 @item 3, send_field_nospatial
8558 like @code{send_field} but skip spatial interlacing check
8561 Default value is @code{send_frame}.
8564 The picture field parity assumed for the input interlaced video, accepts one of
8565 the following values:
8569 assume top field first
8571 assume bottom field first
8573 enable automatic detection
8576 Default value is @code{auto}.
8577 If interlacing is unknown or decoder does not export this information,
8578 top field first will be assumed.
8581 Specify which frames to deinterlace. Accept one of the following
8586 deinterlace all frames
8588 only deinterlace frames marked as interlaced
8591 Default value is @code{all}.
8594 @c man end VIDEO FILTERS
8596 @chapter Video Sources
8597 @c man begin VIDEO SOURCES
8599 Below is a description of the currently available video sources.
8603 Buffer video frames, and make them available to the filter chain.
8605 This source is mainly intended for a programmatic use, in particular
8606 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
8608 This source accepts the following options:
8613 Specify the size (width and height) of the buffered video frames. For the
8614 syntax of this option, check the "Video size" section in the ffmpeg-utils
8624 A string representing the pixel format of the buffered video frames.
8625 It may be a number corresponding to a pixel format, or a pixel format
8629 Specify the timebase assumed by the timestamps of the buffered frames.
8632 Specify the frame rate expected for the video stream.
8634 @item pixel_aspect, sar
8635 Specify the sample aspect ratio assumed by the video frames.
8638 Specify the optional parameters to be used for the scale filter which
8639 is automatically inserted when an input change is detected in the
8640 input size or format.
8645 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
8648 will instruct the source to accept video frames with size 320x240 and
8649 with format "yuv410p", assuming 1/24 as the timestamps timebase and
8650 square pixels (1:1 sample aspect ratio).
8651 Since the pixel format with name "yuv410p" corresponds to the number 6
8652 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
8653 this example corresponds to:
8655 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
8658 Alternatively, the options can be specified as a flat string, but this
8659 syntax is deprecated:
8661 @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}]
8665 Create a pattern generated by an elementary cellular automaton.
8667 The initial state of the cellular automaton can be defined through the
8668 @option{filename}, and @option{pattern} options. If such options are
8669 not specified an initial state is created randomly.
8671 At each new frame a new row in the video is filled with the result of
8672 the cellular automaton next generation. The behavior when the whole
8673 frame is filled is defined by the @option{scroll} option.
8675 This source accepts the following options:
8679 Read the initial cellular automaton state, i.e. the starting row, from
8681 In the file, each non-whitespace character is considered an alive
8682 cell, a newline will terminate the row, and further characters in the
8683 file will be ignored.
8686 Read the initial cellular automaton state, i.e. the starting row, from
8687 the specified string.
8689 Each non-whitespace character in the string is considered an alive
8690 cell, a newline will terminate the row, and further characters in the
8691 string will be ignored.
8694 Set the video rate, that is the number of frames generated per second.
8697 @item random_fill_ratio, ratio
8698 Set the random fill ratio for the initial cellular automaton row. It
8699 is a floating point number value ranging from 0 to 1, defaults to
8702 This option is ignored when a file or a pattern is specified.
8704 @item random_seed, seed
8705 Set the seed for filling randomly the initial row, must be an integer
8706 included between 0 and UINT32_MAX. If not specified, or if explicitly
8707 set to -1, the filter will try to use a good random seed on a best
8711 Set the cellular automaton rule, it is a number ranging from 0 to 255.
8712 Default value is 110.
8715 Set the size of the output video. For the syntax of this option, check
8716 the "Video size" section in the ffmpeg-utils manual.
8718 If @option{filename} or @option{pattern} is specified, the size is set
8719 by default to the width of the specified initial state row, and the
8720 height is set to @var{width} * PHI.
8722 If @option{size} is set, it must contain the width of the specified
8723 pattern string, and the specified pattern will be centered in the
8726 If a filename or a pattern string is not specified, the size value
8727 defaults to "320x518" (used for a randomly generated initial state).
8730 If set to 1, scroll the output upward when all the rows in the output
8731 have been already filled. If set to 0, the new generated row will be
8732 written over the top row just after the bottom row is filled.
8735 @item start_full, full
8736 If set to 1, completely fill the output with generated rows before
8737 outputting the first frame.
8738 This is the default behavior, for disabling set the value to 0.
8741 If set to 1, stitch the left and right row edges together.
8742 This is the default behavior, for disabling set the value to 0.
8745 @subsection Examples
8749 Read the initial state from @file{pattern}, and specify an output of
8752 cellauto=f=pattern:s=200x400
8756 Generate a random initial row with a width of 200 cells, with a fill
8759 cellauto=ratio=2/3:s=200x200
8763 Create a pattern generated by rule 18 starting by a single alive cell
8764 centered on an initial row with width 100:
8766 cellauto=p=@@:s=100x400:full=0:rule=18
8770 Specify a more elaborated initial pattern:
8772 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
8779 Generate a Mandelbrot set fractal, and progressively zoom towards the
8780 point specified with @var{start_x} and @var{start_y}.
8782 This source accepts the following options:
8787 Set the terminal pts value. Default value is 400.
8790 Set the terminal scale value.
8791 Must be a floating point value. Default value is 0.3.
8794 Set the inner coloring mode, that is the algorithm used to draw the
8795 Mandelbrot fractal internal region.
8797 It shall assume one of the following values:
8802 Show time until convergence.
8804 Set color based on point closest to the origin of the iterations.
8809 Default value is @var{mincol}.
8812 Set the bailout value. Default value is 10.0.
8815 Set the maximum of iterations performed by the rendering
8816 algorithm. Default value is 7189.
8819 Set outer coloring mode.
8820 It shall assume one of following values:
8822 @item iteration_count
8823 Set iteration cound mode.
8824 @item normalized_iteration_count
8825 set normalized iteration count mode.
8827 Default value is @var{normalized_iteration_count}.
8830 Set frame rate, expressed as number of frames per second. Default
8834 Set frame size. For the syntax of this option, check the "Video
8835 size" section in the ffmpeg-utils manual. Default value is "640x480".
8838 Set the initial scale value. Default value is 3.0.
8841 Set the initial x position. Must be a floating point value between
8842 -100 and 100. Default value is -0.743643887037158704752191506114774.
8845 Set the initial y position. Must be a floating point value between
8846 -100 and 100. Default value is -0.131825904205311970493132056385139.
8851 Generate various test patterns, as generated by the MPlayer test filter.
8853 The size of the generated video is fixed, and is 256x256.
8854 This source is useful in particular for testing encoding features.
8856 This source accepts the following options:
8861 Specify the frame rate of the sourced video, as the number of frames
8862 generated per second. It has to be a string in the format
8863 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
8864 number or a valid video frame rate abbreviation. The default value is
8868 Set the video duration of the sourced video. The accepted syntax is:
8873 See also the function @code{av_parse_time()}.
8875 If not specified, or the expressed duration is negative, the video is
8876 supposed to be generated forever.
8880 Set the number or the name of the test to perform. Supported tests are:
8895 Default value is "all", which will cycle through the list of all tests.
8898 For example the following:
8903 will generate a "dc_luma" test pattern.
8907 Provide a frei0r source.
8909 To enable compilation of this filter you need to install the frei0r
8910 header and configure FFmpeg with @code{--enable-frei0r}.
8912 This source accepts the following options:
8917 The size of the video to generate. For the syntax of this option, check the
8918 "Video size" section in the ffmpeg-utils manual.
8921 Framerate of the generated video, may be a string of the form
8922 @var{num}/@var{den} or a frame rate abbreviation.
8925 The name to the frei0r source to load. For more information regarding frei0r and
8926 how to set the parameters read the section @ref{frei0r} in the description of
8930 A '|'-separated list of parameters to pass to the frei0r source.
8934 For example, to generate a frei0r partik0l source with size 200x200
8935 and frame rate 10 which is overlayed on the overlay filter main input:
8937 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
8942 Generate a life pattern.
8944 This source is based on a generalization of John Conway's life game.
8946 The sourced input represents a life grid, each pixel represents a cell
8947 which can be in one of two possible states, alive or dead. Every cell
8948 interacts with its eight neighbours, which are the cells that are
8949 horizontally, vertically, or diagonally adjacent.
8951 At each interaction the grid evolves according to the adopted rule,
8952 which specifies the number of neighbor alive cells which will make a
8953 cell stay alive or born. The @option{rule} option allows one to specify
8956 This source accepts the following options:
8960 Set the file from which to read the initial grid state. In the file,
8961 each non-whitespace character is considered an alive cell, and newline
8962 is used to delimit the end of each row.
8964 If this option is not specified, the initial grid is generated
8968 Set the video rate, that is the number of frames generated per second.
8971 @item random_fill_ratio, ratio
8972 Set the random fill ratio for the initial random grid. It is a
8973 floating point number value ranging from 0 to 1, defaults to 1/PHI.
8974 It is ignored when a file is specified.
8976 @item random_seed, seed
8977 Set the seed for filling the initial random grid, must be an integer
8978 included between 0 and UINT32_MAX. If not specified, or if explicitly
8979 set to -1, the filter will try to use a good random seed on a best
8985 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
8986 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
8987 @var{NS} specifies the number of alive neighbor cells which make a
8988 live cell stay alive, and @var{NB} the number of alive neighbor cells
8989 which make a dead cell to become alive (i.e. to "born").
8990 "s" and "b" can be used in place of "S" and "B", respectively.
8992 Alternatively a rule can be specified by an 18-bits integer. The 9
8993 high order bits are used to encode the next cell state if it is alive
8994 for each number of neighbor alive cells, the low order bits specify
8995 the rule for "borning" new cells. Higher order bits encode for an
8996 higher number of neighbor cells.
8997 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
8998 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
9000 Default value is "S23/B3", which is the original Conway's game of life
9001 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
9002 cells, and will born a new cell if there are three alive cells around
9006 Set the size of the output video. For the syntax of this option, check the
9007 "Video size" section in the ffmpeg-utils manual.
9009 If @option{filename} is specified, the size is set by default to the
9010 same size of the input file. If @option{size} is set, it must contain
9011 the size specified in the input file, and the initial grid defined in
9012 that file is centered in the larger resulting area.
9014 If a filename is not specified, the size value defaults to "320x240"
9015 (used for a randomly generated initial grid).
9018 If set to 1, stitch the left and right grid edges together, and the
9019 top and bottom edges also. Defaults to 1.
9022 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
9023 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
9024 value from 0 to 255.
9027 Set the color of living (or new born) cells.
9030 Set the color of dead cells. If @option{mold} is set, this is the first color
9031 used to represent a dead cell.
9034 Set mold color, for definitely dead and moldy cells.
9036 For the syntax of these 3 color options, check the "Color" section in the
9037 ffmpeg-utils manual.
9040 @subsection Examples
9044 Read a grid from @file{pattern}, and center it on a grid of size
9047 life=f=pattern:s=300x300
9051 Generate a random grid of size 200x200, with a fill ratio of 2/3:
9053 life=ratio=2/3:s=200x200
9057 Specify a custom rule for evolving a randomly generated grid:
9063 Full example with slow death effect (mold) using @command{ffplay}:
9065 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
9070 @anchor{haldclutsrc}
9074 @anchor{smptehdbars}
9076 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
9078 The @code{color} source provides an uniformly colored input.
9080 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
9081 @ref{haldclut} filter.
9083 The @code{nullsrc} source returns unprocessed video frames. It is
9084 mainly useful to be employed in analysis / debugging tools, or as the
9085 source for filters which ignore the input data.
9087 The @code{rgbtestsrc} source generates an RGB test pattern useful for
9088 detecting RGB vs BGR issues. You should see a red, green and blue
9089 stripe from top to bottom.
9091 The @code{smptebars} source generates a color bars pattern, based on
9092 the SMPTE Engineering Guideline EG 1-1990.
9094 The @code{smptehdbars} source generates a color bars pattern, based on
9095 the SMPTE RP 219-2002.
9097 The @code{testsrc} source generates a test video pattern, showing a
9098 color pattern, a scrolling gradient and a timestamp. This is mainly
9099 intended for testing purposes.
9101 The sources accept the following options:
9106 Specify the color of the source, only available in the @code{color}
9107 source. For the syntax of this option, check the "Color" section in the
9108 ffmpeg-utils manual.
9111 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
9112 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
9113 pixels to be used as identity matrix for 3D lookup tables. Each component is
9114 coded on a @code{1/(N*N)} scale.
9117 Specify the size of the sourced video. For the syntax of this option, check the
9118 "Video size" section in the ffmpeg-utils manual. The default value is
9121 This option is not available with the @code{haldclutsrc} filter.
9124 Specify the frame rate of the sourced video, as the number of frames
9125 generated per second. It has to be a string in the format
9126 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
9127 number or a valid video frame rate abbreviation. The default value is
9131 Set the sample aspect ratio of the sourced video.
9134 Set the video duration of the sourced video. The accepted syntax is:
9136 [-]HH[:MM[:SS[.m...]]]
9139 See also the function @code{av_parse_time()}.
9141 If not specified, or the expressed duration is negative, the video is
9142 supposed to be generated forever.
9145 Set the number of decimals to show in the timestamp, only available in the
9146 @code{testsrc} source.
9148 The displayed timestamp value will correspond to the original
9149 timestamp value multiplied by the power of 10 of the specified
9150 value. Default value is 0.
9153 For example the following:
9155 testsrc=duration=5.3:size=qcif:rate=10
9158 will generate a video with a duration of 5.3 seconds, with size
9159 176x144 and a frame rate of 10 frames per second.
9161 The following graph description will generate a red source
9162 with an opacity of 0.2, with size "qcif" and a frame rate of 10
9165 color=c=red@@0.2:s=qcif:r=10
9168 If the input content is to be ignored, @code{nullsrc} can be used. The
9169 following command generates noise in the luminance plane by employing
9170 the @code{geq} filter:
9172 nullsrc=s=256x256, geq=random(1)*255:128:128
9175 @subsection Commands
9177 The @code{color} source supports the following commands:
9181 Set the color of the created image. Accepts the same syntax of the
9182 corresponding @option{color} option.
9185 @c man end VIDEO SOURCES
9187 @chapter Video Sinks
9188 @c man begin VIDEO SINKS
9190 Below is a description of the currently available video sinks.
9194 Buffer video frames, and make them available to the end of the filter
9197 This sink is mainly intended for a programmatic use, in particular
9198 through the interface defined in @file{libavfilter/buffersink.h}
9199 or the options system.
9201 It accepts a pointer to an AVBufferSinkContext structure, which
9202 defines the incoming buffers' formats, to be passed as the opaque
9203 parameter to @code{avfilter_init_filter} for initialization.
9207 Null video sink, do absolutely nothing with the input video. It is
9208 mainly useful as a template and to be employed in analysis / debugging
9211 @c man end VIDEO SINKS
9213 @chapter Multimedia Filters
9214 @c man begin MULTIMEDIA FILTERS
9216 Below is a description of the currently available multimedia filters.
9218 @section avectorscope
9220 Convert input audio to a video output, representing the audio vector
9223 The filter is used to measure the difference between channels of stereo
9224 audio stream. A monoaural signal, consisting of identical left and right
9225 signal, results in straight vertical line. Any stereo separation is visible
9226 as a deviation from this line, creating a Lissajous figure.
9227 If the straight (or deviation from it) but horizontal line appears this
9228 indicates that the left and right channels are out of phase.
9230 The filter accepts the following options:
9234 Set the vectorscope mode.
9236 Available values are:
9239 Lissajous rotated by 45 degrees.
9242 Same as above but not rotated.
9245 Default value is @samp{lissajous}.
9248 Set the video size for the output. For the syntax of this option, check the "Video size"
9249 section in the ffmpeg-utils manual. Default value is @code{400x400}.
9252 Set the output frame rate. Default value is @code{25}.
9257 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
9258 Allowed range is @code{[0, 255]}.
9263 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
9264 Allowed range is @code{[0, 255]}.
9267 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
9270 @subsection Examples
9274 Complete example using @command{ffplay}:
9276 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9277 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
9283 Concatenate audio and video streams, joining them together one after the
9286 The filter works on segments of synchronized video and audio streams. All
9287 segments must have the same number of streams of each type, and that will
9288 also be the number of streams at output.
9290 The filter accepts the following options:
9295 Set the number of segments. Default is 2.
9298 Set the number of output video streams, that is also the number of video
9299 streams in each segment. Default is 1.
9302 Set the number of output audio streams, that is also the number of video
9303 streams in each segment. Default is 0.
9306 Activate unsafe mode: do not fail if segments have a different format.
9310 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
9311 @var{a} audio outputs.
9313 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
9314 segment, in the same order as the outputs, then the inputs for the second
9317 Related streams do not always have exactly the same duration, for various
9318 reasons including codec frame size or sloppy authoring. For that reason,
9319 related synchronized streams (e.g. a video and its audio track) should be
9320 concatenated at once. The concat filter will use the duration of the longest
9321 stream in each segment (except the last one), and if necessary pad shorter
9322 audio streams with silence.
9324 For this filter to work correctly, all segments must start at timestamp 0.
9326 All corresponding streams must have the same parameters in all segments; the
9327 filtering system will automatically select a common pixel format for video
9328 streams, and a common sample format, sample rate and channel layout for
9329 audio streams, but other settings, such as resolution, must be converted
9330 explicitly by the user.
9332 Different frame rates are acceptable but will result in variable frame rate
9333 at output; be sure to configure the output file to handle it.
9335 @subsection Examples
9339 Concatenate an opening, an episode and an ending, all in bilingual version
9340 (video in stream 0, audio in streams 1 and 2):
9342 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
9343 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
9344 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
9345 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
9349 Concatenate two parts, handling audio and video separately, using the
9350 (a)movie sources, and adjusting the resolution:
9352 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
9353 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
9354 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
9356 Note that a desync will happen at the stitch if the audio and video streams
9357 do not have exactly the same duration in the first file.
9363 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
9364 it unchanged. By default, it logs a message at a frequency of 10Hz with the
9365 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
9366 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
9368 The filter also has a video output (see the @var{video} option) with a real
9369 time graph to observe the loudness evolution. The graphic contains the logged
9370 message mentioned above, so it is not printed anymore when this option is set,
9371 unless the verbose logging is set. The main graphing area contains the
9372 short-term loudness (3 seconds of analysis), and the gauge on the right is for
9373 the momentary loudness (400 milliseconds).
9375 More information about the Loudness Recommendation EBU R128 on
9376 @url{http://tech.ebu.ch/loudness}.
9378 The filter accepts the following options:
9383 Activate the video output. The audio stream is passed unchanged whether this
9384 option is set or no. The video stream will be the first output stream if
9385 activated. Default is @code{0}.
9388 Set the video size. This option is for video only. For the syntax of this
9389 option, check the "Video size" section in the ffmpeg-utils manual. Default
9390 and minimum resolution is @code{640x480}.
9393 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
9394 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
9395 other integer value between this range is allowed.
9398 Set metadata injection. If set to @code{1}, the audio input will be segmented
9399 into 100ms output frames, each of them containing various loudness information
9400 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
9402 Default is @code{0}.
9405 Force the frame logging level.
9407 Available values are:
9410 information logging level
9412 verbose logging level
9415 By default, the logging level is set to @var{info}. If the @option{video} or
9416 the @option{metadata} options are set, it switches to @var{verbose}.
9421 Available modes can be cumulated (the option is a @code{flag} type). Possible
9425 Disable any peak mode (default).
9427 Enable sample-peak mode.
9429 Simple peak mode looking for the higher sample value. It logs a message
9430 for sample-peak (identified by @code{SPK}).
9432 Enable true-peak mode.
9434 If enabled, the peak lookup is done on an over-sampled version of the input
9435 stream for better peak accuracy. It logs a message for true-peak.
9436 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
9437 This mode requires a build with @code{libswresample}.
9442 @subsection Examples
9446 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
9448 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
9452 Run an analysis with @command{ffmpeg}:
9454 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
9458 @section interleave, ainterleave
9460 Temporally interleave frames from several inputs.
9462 @code{interleave} works with video inputs, @code{ainterleave} with audio.
9464 These filters read frames from several inputs and send the oldest
9465 queued frame to the output.
9467 Input streams must have a well defined, monotonically increasing frame
9470 In order to submit one frame to output, these filters need to enqueue
9471 at least one frame for each input, so they cannot work in case one
9472 input is not yet terminated and will not receive incoming frames.
9474 For example consider the case when one input is a @code{select} filter
9475 which always drop input frames. The @code{interleave} filter will keep
9476 reading from that input, but it will never be able to send new frames
9477 to output until the input will send an end-of-stream signal.
9479 Also, depending on inputs synchronization, the filters will drop
9480 frames in case one input receives more frames than the other ones, and
9481 the queue is already filled.
9483 These filters accept the following options:
9487 Set the number of different inputs, it is 2 by default.
9490 @subsection Examples
9494 Interleave frames belonging to different streams using @command{ffmpeg}:
9496 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
9500 Add flickering blur effect:
9502 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
9506 @section perms, aperms
9508 Set read/write permissions for the output frames.
9510 These filters are mainly aimed at developers to test direct path in the
9511 following filter in the filtergraph.
9513 The filters accept the following options:
9517 Select the permissions mode.
9519 It accepts the following values:
9522 Do nothing. This is the default.
9524 Set all the output frames read-only.
9526 Set all the output frames directly writable.
9528 Make the frame read-only if writable, and writable if read-only.
9530 Set each output frame read-only or writable randomly.
9534 Set the seed for the @var{random} mode, must be an integer included between
9535 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
9536 @code{-1}, the filter will try to use a good random seed on a best effort
9540 Note: in case of auto-inserted filter between the permission filter and the
9541 following one, the permission might not be received as expected in that
9542 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
9543 perms/aperms filter can avoid this problem.
9545 @section select, aselect
9547 Select frames to pass in output.
9549 This filter accepts the following options:
9554 Set expression, which is evaluated for each input frame.
9556 If the expression is evaluated to zero, the frame is discarded.
9558 If the evaluation result is negative or NaN, the frame is sent to the
9559 first output; otherwise it is sent to the output with index
9560 @code{ceil(val)-1}, assuming that the input index starts from 0.
9562 For example a value of @code{1.2} corresponds to the output with index
9563 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
9566 Set the number of outputs. The output to which to send the selected
9567 frame is based on the result of the evaluation. Default value is 1.
9570 The expression can contain the following constants:
9574 the sequential number of the filtered frame, starting from 0
9577 the sequential number of the selected frame, starting from 0
9579 @item prev_selected_n
9580 the sequential number of the last selected frame, NAN if undefined
9583 timebase of the input timestamps
9586 the PTS (Presentation TimeStamp) of the filtered video frame,
9587 expressed in @var{TB} units, NAN if undefined
9590 the PTS (Presentation TimeStamp) of the filtered video frame,
9591 expressed in seconds, NAN if undefined
9594 the PTS of the previously filtered video frame, NAN if undefined
9596 @item prev_selected_pts
9597 the PTS of the last previously filtered video frame, NAN if undefined
9599 @item prev_selected_t
9600 the PTS of the last previously selected video frame, NAN if undefined
9603 the PTS of the first video frame in the video, NAN if undefined
9606 the time of the first video frame in the video, NAN if undefined
9608 @item pict_type @emph{(video only)}
9609 the type of the filtered frame, can assume one of the following
9621 @item interlace_type @emph{(video only)}
9622 the frame interlace type, can assume one of the following values:
9625 the frame is progressive (not interlaced)
9627 the frame is top-field-first
9629 the frame is bottom-field-first
9632 @item consumed_sample_n @emph{(audio only)}
9633 the number of selected samples before the current frame
9635 @item samples_n @emph{(audio only)}
9636 the number of samples in the current frame
9638 @item sample_rate @emph{(audio only)}
9639 the input sample rate
9642 1 if the filtered frame is a key-frame, 0 otherwise
9645 the position in the file of the filtered frame, -1 if the information
9646 is not available (e.g. for synthetic video)
9648 @item scene @emph{(video only)}
9649 value between 0 and 1 to indicate a new scene; a low value reflects a low
9650 probability for the current frame to introduce a new scene, while a higher
9651 value means the current frame is more likely to be one (see the example below)
9655 The default value of the select expression is "1".
9657 @subsection Examples
9661 Select all frames in input:
9666 The example above is the same as:
9678 Select only I-frames:
9680 select='eq(pict_type\,I)'
9684 Select one frame every 100:
9686 select='not(mod(n\,100))'
9690 Select only frames contained in the 10-20 time interval:
9692 select=between(t\,10\,20)
9696 Select only I frames contained in the 10-20 time interval:
9698 select=between(t\,10\,20)*eq(pict_type\,I)
9702 Select frames with a minimum distance of 10 seconds:
9704 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
9708 Use aselect to select only audio frames with samples number > 100:
9710 aselect='gt(samples_n\,100)'
9714 Create a mosaic of the first scenes:
9716 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
9719 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
9723 Send even and odd frames to separate outputs, and compose them:
9725 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
9729 @section sendcmd, asendcmd
9731 Send commands to filters in the filtergraph.
9733 These filters read commands to be sent to other filters in the
9736 @code{sendcmd} must be inserted between two video filters,
9737 @code{asendcmd} must be inserted between two audio filters, but apart
9738 from that they act the same way.
9740 The specification of commands can be provided in the filter arguments
9741 with the @var{commands} option, or in a file specified by the
9742 @var{filename} option.
9744 These filters accept the following options:
9747 Set the commands to be read and sent to the other filters.
9749 Set the filename of the commands to be read and sent to the other
9753 @subsection Commands syntax
9755 A commands description consists of a sequence of interval
9756 specifications, comprising a list of commands to be executed when a
9757 particular event related to that interval occurs. The occurring event
9758 is typically the current frame time entering or leaving a given time
9761 An interval is specified by the following syntax:
9763 @var{START}[-@var{END}] @var{COMMANDS};
9766 The time interval is specified by the @var{START} and @var{END} times.
9767 @var{END} is optional and defaults to the maximum time.
9769 The current frame time is considered within the specified interval if
9770 it is included in the interval [@var{START}, @var{END}), that is when
9771 the time is greater or equal to @var{START} and is lesser than
9774 @var{COMMANDS} consists of a sequence of one or more command
9775 specifications, separated by ",", relating to that interval. The
9776 syntax of a command specification is given by:
9778 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
9781 @var{FLAGS} is optional and specifies the type of events relating to
9782 the time interval which enable sending the specified command, and must
9783 be a non-null sequence of identifier flags separated by "+" or "|" and
9784 enclosed between "[" and "]".
9786 The following flags are recognized:
9789 The command is sent when the current frame timestamp enters the
9790 specified interval. In other words, the command is sent when the
9791 previous frame timestamp was not in the given interval, and the
9795 The command is sent when the current frame timestamp leaves the
9796 specified interval. In other words, the command is sent when the
9797 previous frame timestamp was in the given interval, and the
9801 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
9804 @var{TARGET} specifies the target of the command, usually the name of
9805 the filter class or a specific filter instance name.
9807 @var{COMMAND} specifies the name of the command for the target filter.
9809 @var{ARG} is optional and specifies the optional list of argument for
9810 the given @var{COMMAND}.
9812 Between one interval specification and another, whitespaces, or
9813 sequences of characters starting with @code{#} until the end of line,
9814 are ignored and can be used to annotate comments.
9816 A simplified BNF description of the commands specification syntax
9819 @var{COMMAND_FLAG} ::= "enter" | "leave"
9820 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
9821 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
9822 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
9823 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
9824 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
9827 @subsection Examples
9831 Specify audio tempo change at second 4:
9833 asendcmd=c='4.0 atempo tempo 1.5',atempo
9837 Specify a list of drawtext and hue commands in a file.
9839 # show text in the interval 5-10
9840 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
9841 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
9843 # desaturate the image in the interval 15-20
9844 15.0-20.0 [enter] hue s 0,
9845 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
9847 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
9849 # apply an exponential saturation fade-out effect, starting from time 25
9850 25 [enter] hue s exp(25-t)
9853 A filtergraph allowing to read and process the above command list
9854 stored in a file @file{test.cmd}, can be specified with:
9856 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
9861 @section setpts, asetpts
9863 Change the PTS (presentation timestamp) of the input frames.
9865 @code{setpts} works on video frames, @code{asetpts} on audio frames.
9867 This filter accepts the following options:
9872 The expression which is evaluated for each frame to construct its timestamp.
9876 The expression is evaluated through the eval API and can contain the following
9881 frame rate, only defined for constant frame-rate video
9884 the presentation timestamp in input
9887 the count of the input frame for video or the number of consumed samples,
9888 not including the current frame for audio, starting from 0.
9890 @item NB_CONSUMED_SAMPLES
9891 the number of consumed samples, not including the current frame (only
9895 the number of samples in the current frame (only audio)
9897 @item SAMPLE_RATE, SR
9901 the PTS of the first frame
9904 the time in seconds of the first frame
9907 tell if the current frame is interlaced
9910 the time in seconds of the current frame
9913 original position in the file of the frame, or undefined if undefined
9914 for the current frame
9920 previous input time in seconds
9926 previous output time in seconds
9929 wallclock (RTC) time in microseconds. This is deprecated, use time(0)
9933 wallclock (RTC) time at the start of the movie in microseconds
9936 timebase of the input timestamps
9940 @subsection Examples
9944 Start counting PTS from zero
9950 Apply fast motion effect:
9956 Apply slow motion effect:
9962 Set fixed rate of 25 frames per second:
9968 Set fixed rate 25 fps with some jitter:
9970 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
9974 Apply an offset of 10 seconds to the input PTS:
9980 Generate timestamps from a "live source" and rebase onto the current timebase:
9982 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
9986 Generate timestamps by counting samples:
9993 @section settb, asettb
9995 Set the timebase to use for the output frames timestamps.
9996 It is mainly useful for testing timebase configuration.
9998 This filter accepts the following options:
10003 The expression which is evaluated into the output timebase.
10007 The value for @option{tb} is an arithmetic expression representing a
10008 rational. The expression can contain the constants "AVTB" (the default
10009 timebase), "intb" (the input timebase) and "sr" (the sample rate,
10010 audio only). Default value is "intb".
10012 @subsection Examples
10016 Set the timebase to 1/25:
10022 Set the timebase to 1/10:
10028 Set the timebase to 1001/1000:
10034 Set the timebase to 2*intb:
10040 Set the default timebase value:
10046 @section showspectrum
10048 Convert input audio to a video output, representing the audio frequency
10051 The filter accepts the following options:
10055 Specify the video size for the output. For the syntax of this option, check
10056 the "Video size" section in the ffmpeg-utils manual. Default value is
10060 Specify if the spectrum should slide along the window. Default value is
10064 Specify display mode.
10066 It accepts the following values:
10069 all channels are displayed in the same row
10071 all channels are displayed in separate rows
10074 Default value is @samp{combined}.
10077 Specify display color mode.
10079 It accepts the following values:
10082 each channel is displayed in a separate color
10084 each channel is is displayed using the same color scheme
10087 Default value is @samp{channel}.
10090 Specify scale used for calculating intensity color values.
10092 It accepts the following values:
10097 square root, default
10104 Default value is @samp{sqrt}.
10107 Set saturation modifier for displayed colors. Negative values provide
10108 alternative color scheme. @code{0} is no saturation at all.
10109 Saturation must be in [-10.0, 10.0] range.
10110 Default value is @code{1}.
10113 Set window function.
10115 It accepts the following values:
10118 No samples pre-processing (do not expect this to be faster)
10127 Default value is @code{hann}.
10130 The usage is very similar to the showwaves filter; see the examples in that
10133 @subsection Examples
10137 Large window with logarithmic color scaling:
10139 showspectrum=s=1280x480:scale=log
10143 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
10145 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10146 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
10152 Convert input audio to a video output, representing the samples waves.
10154 The filter accepts the following options:
10158 Specify the video size for the output. For the syntax of this option, check
10159 the "Video size" section in the ffmpeg-utils manual. Default value
10165 Available values are:
10168 Draw a point for each sample.
10171 Draw a vertical line for each sample.
10174 Default value is @code{point}.
10177 Set the number of samples which are printed on the same column. A
10178 larger value will decrease the frame rate. Must be a positive
10179 integer. This option can be set only if the value for @var{rate}
10180 is not explicitly specified.
10183 Set the (approximate) output frame rate. This is done by setting the
10184 option @var{n}. Default value is "25".
10188 @subsection Examples
10192 Output the input file audio and the corresponding video representation
10195 amovie=a.mp3,asplit[out0],showwaves[out1]
10199 Create a synthetic signal and show it with showwaves, forcing a
10200 frame rate of 30 frames per second:
10202 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
10206 @section split, asplit
10208 Split input into several identical outputs.
10210 @code{asplit} works with audio input, @code{split} with video.
10212 The filter accepts a single parameter which specifies the number of outputs. If
10213 unspecified, it defaults to 2.
10215 @subsection Examples
10219 Create two separate outputs from the same input:
10221 [in] split [out0][out1]
10225 To create 3 or more outputs, you need to specify the number of
10228 [in] asplit=3 [out0][out1][out2]
10232 Create two separate outputs from the same input, one cropped and
10235 [in] split [splitout1][splitout2];
10236 [splitout1] crop=100:100:0:0 [cropout];
10237 [splitout2] pad=200:200:100:100 [padout];
10241 Create 5 copies of the input audio with @command{ffmpeg}:
10243 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
10249 Receive commands sent through a libzmq client, and forward them to
10250 filters in the filtergraph.
10252 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
10253 must be inserted between two video filters, @code{azmq} between two
10256 To enable these filters you need to install the libzmq library and
10257 headers and configure FFmpeg with @code{--enable-libzmq}.
10259 For more information about libzmq see:
10260 @url{http://www.zeromq.org/}
10262 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
10263 receives messages sent through a network interface defined by the
10264 @option{bind_address} option.
10266 The received message must be in the form:
10268 @var{TARGET} @var{COMMAND} [@var{ARG}]
10271 @var{TARGET} specifies the target of the command, usually the name of
10272 the filter class or a specific filter instance name.
10274 @var{COMMAND} specifies the name of the command for the target filter.
10276 @var{ARG} is optional and specifies the optional argument list for the
10277 given @var{COMMAND}.
10279 Upon reception, the message is processed and the corresponding command
10280 is injected into the filtergraph. Depending on the result, the filter
10281 will send a reply to the client, adopting the format:
10283 @var{ERROR_CODE} @var{ERROR_REASON}
10287 @var{MESSAGE} is optional.
10289 @subsection Examples
10291 Look at @file{tools/zmqsend} for an example of a zmq client which can
10292 be used to send commands processed by these filters.
10294 Consider the following filtergraph generated by @command{ffplay}
10296 ffplay -dumpgraph 1 -f lavfi "
10297 color=s=100x100:c=red [l];
10298 color=s=100x100:c=blue [r];
10299 nullsrc=s=200x100, zmq [bg];
10300 [bg][l] overlay [bg+l];
10301 [bg+l][r] overlay=x=100 "
10304 To change the color of the left side of the video, the following
10305 command can be used:
10307 echo Parsed_color_0 c yellow | tools/zmqsend
10310 To change the right side:
10312 echo Parsed_color_1 c pink | tools/zmqsend
10315 @c man end MULTIMEDIA FILTERS
10317 @chapter Multimedia Sources
10318 @c man begin MULTIMEDIA SOURCES
10320 Below is a description of the currently available multimedia sources.
10324 This is the same as @ref{movie} source, except it selects an audio
10330 Read audio and/or video stream(s) from a movie container.
10332 This filter accepts the following options:
10336 The name of the resource to read (not necessarily a file but also a device or a
10337 stream accessed through some protocol).
10339 @item format_name, f
10340 Specifies the format assumed for the movie to read, and can be either
10341 the name of a container or an input device. If not specified the
10342 format is guessed from @var{movie_name} or by probing.
10344 @item seek_point, sp
10345 Specifies the seek point in seconds, the frames will be output
10346 starting from this seek point, the parameter is evaluated with
10347 @code{av_strtod} so the numerical value may be suffixed by an IS
10348 postfix. Default value is "0".
10351 Specifies the streams to read. Several streams can be specified,
10352 separated by "+". The source will then have as many outputs, in the
10353 same order. The syntax is explained in the ``Stream specifiers''
10354 section in the ffmpeg manual. Two special names, "dv" and "da" specify
10355 respectively the default (best suited) video and audio stream. Default
10356 is "dv", or "da" if the filter is called as "amovie".
10358 @item stream_index, si
10359 Specifies the index of the video stream to read. If the value is -1,
10360 the best suited video stream will be automatically selected. Default
10361 value is "-1". Deprecated. If the filter is called "amovie", it will select
10362 audio instead of video.
10365 Specifies how many times to read the stream in sequence.
10366 If the value is less than 1, the stream will be read again and again.
10367 Default value is "1".
10369 Note that when the movie is looped the source timestamps are not
10370 changed, so it will generate non monotonically increasing timestamps.
10373 This filter allows one to overlay a second video on top of main input of
10374 a filtergraph as shown in this graph:
10376 input -----------> deltapts0 --> overlay --> output
10379 movie --> scale--> deltapts1 -------+
10382 @subsection Examples
10386 Skip 3.2 seconds from the start of the avi file in.avi, and overlay it
10387 on top of the input labelled as "in":
10389 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
10390 [in] setpts=PTS-STARTPTS [main];
10391 [main][over] overlay=16:16 [out]
10395 Read from a video4linux2 device, and overlay it on top of the input
10398 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
10399 [in] setpts=PTS-STARTPTS [main];
10400 [main][over] overlay=16:16 [out]
10404 Read the first video stream and the audio stream with id 0x81 from
10405 dvd.vob; the video is connected to the pad named "video" and the audio is
10406 connected to the pad named "audio":
10408 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
10412 @c man end MULTIMEDIA SOURCES