1 @chapter Filtering Introduction
2 @c man begin FILTERING INTRODUCTION
4 Filtering in FFmpeg is enabled through the libavfilter library.
6 In libavfilter, a filter can have multiple inputs and multiple
8 To illustrate the sorts of things that are possible, we consider the
13 input --> split ---------------------> overlay --> output
16 +-----> crop --> vflip -------+
19 This filtergraph splits the input stream in two streams, then sends one
20 stream through the crop filter and the vflip filter, before merging it
21 back with the other stream by overlaying it on top. You can use the
22 following command to achieve this:
25 ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT
28 The result will be that the top half of the video is mirrored
29 onto the bottom half of the output video.
31 Filters in the same linear chain are separated by commas, and distinct
32 linear chains of filters are separated by semicolons. In our example,
33 @var{crop,vflip} are in one linear chain, @var{split} and
34 @var{overlay} are separately in another. The points where the linear
35 chains join are labelled by names enclosed in square brackets. In the
36 example, the split filter generates two outputs that are associated to
37 the labels @var{[main]} and @var{[tmp]}.
39 The stream sent to the second output of @var{split}, labelled as
40 @var{[tmp]}, is processed through the @var{crop} filter, which crops
41 away the lower half part of the video, and then vertically flipped. The
42 @var{overlay} filter takes in input the first unchanged output of the
43 split filter (which was labelled as @var{[main]}), and overlay on its
44 lower half the output generated by the @var{crop,vflip} filterchain.
46 Some filters take in input a list of parameters: they are specified
47 after the filter name and an equal sign, and are separated from each other
50 There exist so-called @var{source filters} that do not have an
51 audio/video input, and @var{sink filters} that will not have audio/video
54 @c man end FILTERING INTRODUCTION
57 @c man begin GRAPH2DOT
59 The @file{graph2dot} program included in the FFmpeg @file{tools}
60 directory can be used to parse a filtergraph description and issue a
61 corresponding textual representation in the dot language.
68 to see how to use @file{graph2dot}.
70 You can then pass the dot description to the @file{dot} program (from
71 the graphviz suite of programs) and obtain a graphical representation
74 For example the sequence of commands:
76 echo @var{GRAPH_DESCRIPTION} | \
77 tools/graph2dot -o graph.tmp && \
78 dot -Tpng graph.tmp -o graph.png && \
82 can be used to create and display an image representing the graph
83 described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
84 a complete self-contained graph, with its inputs and outputs explicitly defined.
85 For example if your command line is of the form:
87 ffmpeg -i infile -vf scale=640:360 outfile
89 your @var{GRAPH_DESCRIPTION} string will need to be of the form:
91 nullsrc,scale=640:360,nullsink
93 you may also need to set the @var{nullsrc} parameters and add a @var{format}
94 filter in order to simulate a specific input file.
98 @chapter Filtergraph description
99 @c man begin FILTERGRAPH DESCRIPTION
101 A filtergraph is a directed graph of connected filters. It can contain
102 cycles, and there can be multiple links between a pair of
103 filters. Each link has one input pad on one side connecting it to one
104 filter from which it takes its input, and one output pad on the other
105 side connecting it to one filter accepting its output.
107 Each filter in a filtergraph is an instance of a filter class
108 registered in the application, which defines the features and the
109 number of input and output pads of the filter.
111 A filter with no input pads is called a "source", and a filter with no
112 output pads is called a "sink".
114 @anchor{Filtergraph syntax}
115 @section Filtergraph syntax
117 A filtergraph has a textual representation, which is
118 recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
119 options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the
120 @code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} functions defined in
121 @file{libavfilter/avfilter.h}.
123 A filterchain consists of a sequence of connected filters, each one
124 connected to the previous one in the sequence. A filterchain is
125 represented by a list of ","-separated filter descriptions.
127 A filtergraph consists of a sequence of filterchains. A sequence of
128 filterchains is represented by a list of ";"-separated filterchain
131 A filter is represented by a string of the form:
132 [@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
134 @var{filter_name} is the name of the filter class of which the
135 described filter is an instance of, and has to be the name of one of
136 the filter classes registered in the program.
137 The name of the filter class is optionally followed by a string
140 @var{arguments} is a string which contains the parameters used to
141 initialize the filter instance. It may have one of two forms:
145 A ':'-separated list of @var{key=value} pairs.
148 A ':'-separated list of @var{value}. In this case, the keys are assumed to be
149 the option names in the order they are declared. E.g. the @code{fade} filter
150 declares three options in this order -- @option{type}, @option{start_frame} and
151 @option{nb_frames}. Then the parameter list @var{in:0:30} means that the value
152 @var{in} is assigned to the option @option{type}, @var{0} to
153 @option{start_frame} and @var{30} to @option{nb_frames}.
156 A ':'-separated list of mixed direct @var{value} and long @var{key=value}
157 pairs. The direct @var{value} must precede the @var{key=value} pairs, and
158 follow the same constraints order of the previous point. The following
159 @var{key=value} pairs can be set in any preferred order.
163 If the option value itself is a list of items (e.g. the @code{format} filter
164 takes a list of pixel formats), the items in the list are usually separated by
167 The list of arguments can be quoted using the character "'" as initial
168 and ending mark, and the character '\' for escaping the characters
169 within the quoted text; otherwise the argument string is considered
170 terminated when the next special character (belonging to the set
171 "[]=;,") is encountered.
173 The name and arguments of the filter are optionally preceded and
174 followed by a list of link labels.
175 A link label allows one to name a link and associate it to a filter output
176 or input pad. The preceding labels @var{in_link_1}
177 ... @var{in_link_N}, are associated to the filter input pads,
178 the following labels @var{out_link_1} ... @var{out_link_M}, are
179 associated to the output pads.
181 When two link labels with the same name are found in the
182 filtergraph, a link between the corresponding input and output pad is
185 If an output pad is not labelled, it is linked by default to the first
186 unlabelled input pad of the next filter in the filterchain.
187 For example in the filterchain
189 nullsrc, split[L1], [L2]overlay, nullsink
191 the split filter instance has two output pads, and the overlay filter
192 instance two input pads. The first output pad of split is labelled
193 "L1", the first input pad of overlay is labelled "L2", and the second
194 output pad of split is linked to the second input pad of overlay,
195 which are both unlabelled.
197 In a complete filterchain all the unlabelled filter input and output
198 pads must be connected. A filtergraph is considered valid if all the
199 filter input and output pads of all the filterchains are connected.
201 Libavfilter will automatically insert @ref{scale} filters where format
202 conversion is required. It is possible to specify swscale flags
203 for those automatically inserted scalers by prepending
204 @code{sws_flags=@var{flags};}
205 to the filtergraph description.
207 Here is a BNF description of the filtergraph syntax:
209 @var{NAME} ::= sequence of alphanumeric characters and '_'
210 @var{LINKLABEL} ::= "[" @var{NAME} "]"
211 @var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
212 @var{FILTER_ARGUMENTS} ::= sequence of chars (possibly quoted)
213 @var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}]
214 @var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
215 @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
218 @section Notes on filtergraph escaping
220 Filtergraph description composition entails several levels of
221 escaping. See @ref{quoting_and_escaping,,the "Quoting and escaping"
222 section in the ffmpeg-utils(1) manual,ffmpeg-utils} for more
223 information about the employed escaping procedure.
225 A first level escaping affects the content of each filter option
226 value, which may contain the special character @code{:} used to
227 separate values, or one of the escaping characters @code{\'}.
229 A second level escaping affects the whole filter description, which
230 may contain the escaping characters @code{\'} or the special
231 characters @code{[],;} used by the filtergraph description.
233 Finally, when you specify a filtergraph on a shell commandline, you
234 need to perform a third level escaping for the shell special
235 characters contained within it.
237 For example, consider the following string to be embedded in
238 the @ref{drawtext} filter description @option{text} value:
240 this is a 'string': may contain one, or more, special characters
243 This string contains the @code{'} special escaping character, and the
244 @code{:} special character, so it needs to be escaped in this way:
246 text=this is a \'string\'\: may contain one, or more, special characters
249 A second level of escaping is required when embedding the filter
250 description in a filtergraph description, in order to escape all the
251 filtergraph special characters. Thus the example above becomes:
253 drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters
255 (note that in addition to the @code{\'} escaping special characters,
256 also @code{,} needs to be escaped).
258 Finally an additional level of escaping is needed when writing the
259 filtergraph description in a shell command, which depends on the
260 escaping rules of the adopted shell. For example, assuming that
261 @code{\} is special and needs to be escaped with another @code{\}, the
262 previous string will finally result in:
264 -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"
267 @chapter Timeline editing
269 Some filters support a generic @option{enable} option. For the filters
270 supporting timeline editing, this option can be set to an expression which is
271 evaluated before sending a frame to the filter. If the evaluation is non-zero,
272 the filter will be enabled, otherwise the frame will be sent unchanged to the
273 next filter in the filtergraph.
275 The expression accepts the following values:
278 timestamp expressed in seconds, NAN if the input timestamp is unknown
281 sequential number of the input frame, starting from 0
284 the position in the file of the input frame, NAN if unknown
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 It accepts the following parameters:
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 It accepts the following 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 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 It accepts the following parameters:
711 The number of inputs. If unspecified, it defaults to 2.
714 How to determine the end-of-stream.
718 The duration of the longest input. (default)
721 The duration of the shortest input.
724 The duration of the first input.
728 @item dropout_transition
729 The 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 It accepts the following parameters:
864 The (sequential) number of the input frame, starting from 0.
867 The 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 The 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 The sample rate for the audio frame.
887 The number of samples (per channel) in the frame.
890 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
891 audio, 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 It 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 It accepts the following 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 The minimum difference between timestamps and audio data (in seconds) to trigger
994 adding/dropping samples. The default value is 0.1. If you get an imperfect
995 sync with this filter, try setting this parameter to 0.
998 The maximum compensation in samples per second. Only relevant with compensate=1.
999 The default value is 500.
1002 Assume that the first PTS should be this value. The time base is 1 / sample
1003 rate. This allows for padding/trimming at the start of the stream. By default,
1004 no 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 It accepts the following parameters:
1042 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1043 sample 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 The maximum duration of the output in seconds.
1062 The number of the first sample that should be output.
1065 The 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 to have 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 It accepts the following parameters:
1215 @item channel_layout
1216 The 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 indices.
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 from an input audio stream into a separate output stream.
1247 It accepts the following parameters:
1249 @item channel_layout
1250 The channel layout of the input stream. The 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 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 the audio's dynamic range.
1272 It accepts the following parameters:
1278 A 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 A 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. It defaults to 0.01.
1301 Set the additional gain in dB to be applied at all points on the transfer
1302 function. This allows for easy adjustment of the overall gain.
1306 Set an initial volume, in dB, to be assumed for each channel when filtering
1307 starts. This permits the user to supply a nominal level initially, so that, for
1308 example, a very large gain is not applied to initial signal levels before the
1309 companding has begun to operate. A typical value for audio which is initially
1310 quiet is -90 dB. It defaults to 0.
1313 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1314 delayed before being fed to the volume adjuster. Specifying a delay
1315 approximately equal to the attack/decay times allows the filter to effectively
1316 operate in predictive rather than reactive mode. It defaults to 0.
1320 @subsection Examples
1324 Make music with both quiet and loud passages suitable for listening to in a
1327 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1331 A noise gate for when the noise is at a lower level than the signal:
1333 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1337 Here is another noise gate, this time for when the noise is at a higher level
1338 than the signal (making it, in some ways, similar to squelch):
1340 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1346 Make audio easier to listen to on headphones.
1348 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1349 so that when listened to on headphones the stereo image is moved from
1350 inside your head (standard for headphones) to outside and in front of
1351 the listener (standard for speakers).
1357 Apply a two-pole peaking equalisation (EQ) filter. With this
1358 filter, the signal-level at and around a selected frequency can
1359 be increased or decreased, whilst (unlike bandpass and bandreject
1360 filters) that at all other frequencies is unchanged.
1362 In order to produce complex equalisation curves, this filter can
1363 be given several times, each with a different central frequency.
1365 The filter accepts the following options:
1369 Set the filter's central frequency in Hz.
1372 Set method to specify band-width of filter.
1385 Specify the band-width of a filter in width_type units.
1388 Set the required gain or attenuation in dB.
1389 Beware of clipping when using a positive gain.
1392 @subsection Examples
1395 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1397 equalizer=f=1000:width_type=h:width=200:g=-10
1401 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1403 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1409 Apply a high-pass filter with 3dB point frequency.
1410 The filter can be either single-pole, or double-pole (the default).
1411 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1413 The filter accepts the following options:
1417 Set frequency in Hz. Default is 3000.
1420 Set number of poles. Default is 2.
1423 Set method to specify band-width of filter.
1436 Specify the band-width of a filter in width_type units.
1437 Applies only to double-pole filter.
1438 The default is 0.707q and gives a Butterworth response.
1443 Join multiple input streams into one multi-channel stream.
1445 It accepts the following parameters:
1449 The number of input streams. It defaults to 2.
1451 @item channel_layout
1452 The desired output channel layout. It defaults to stereo.
1455 Map channels from inputs to output. The argument is a '|'-separated list of
1456 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1457 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1458 can be either the name of the input channel (e.g. FL for front left) or its
1459 index in the specified input stream. @var{out_channel} is the name of the output
1463 The filter will attempt to guess the mappings when they are not specified
1464 explicitly. It does so by first trying to find an unused matching input channel
1465 and if that fails it picks the first unused input channel.
1467 Join 3 inputs (with properly set channel layouts):
1469 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1472 Build a 5.1 output from 6 single-channel streams:
1474 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1475 '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'
1481 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1483 To enable compilation of this filter you need to configure FFmpeg with
1484 @code{--enable-ladspa}.
1488 Specifies the name of LADSPA plugin library to load. If the environment
1489 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1490 each one of the directories specified by the colon separated list in
1491 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1492 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1493 @file{/usr/lib/ladspa/}.
1496 Specifies the plugin within the library. Some libraries contain only
1497 one plugin, but others contain many of them. If this is not set filter
1498 will list all available plugins within the specified library.
1501 Set the '|' separated list of controls which are zero or more floating point
1502 values that determine the behavior of the loaded plugin (for example delay,
1504 Controls need to be defined using the following syntax:
1505 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1506 @var{valuei} is the value set on the @var{i}-th control.
1507 If @option{controls} is set to @code{help}, all available controls and
1508 their valid ranges are printed.
1510 @item sample_rate, s
1511 Specify the sample rate, default to 44100. Only used if plugin have
1515 Set the number of samples per channel per each output frame, default
1516 is 1024. Only used if plugin have zero inputs.
1519 Set the minimum duration of the sourced audio. See the function
1520 @code{av_parse_time()} for the accepted format, also check the "Time duration"
1521 section in the ffmpeg-utils manual.
1522 Note that the resulting duration may be greater than the specified duration,
1523 as the generated audio is always cut at the end of a complete frame.
1524 If not specified, or the expressed duration is negative, the audio is
1525 supposed to be generated forever.
1526 Only used if plugin have zero inputs.
1530 @subsection Examples
1534 List all available plugins within amp (LADSPA example plugin) library:
1540 List all available controls and their valid ranges for @code{vcf_notch}
1541 plugin from @code{VCF} library:
1543 ladspa=f=vcf:p=vcf_notch:c=help
1547 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1550 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1554 Add reverberation to the audio using TAP-plugins
1555 (Tom's Audio Processing plugins):
1557 ladspa=file=tap_reverb:tap_reverb
1561 Generate white noise, with 0.2 amplitude:
1563 ladspa=file=cmt:noise_source_white:c=c0=.2
1567 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1568 @code{C* Audio Plugin Suite} (CAPS) library:
1570 ladspa=file=caps:Click:c=c1=20'
1574 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1576 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1580 @subsection Commands
1582 This filter supports the following commands:
1585 Modify the @var{N}-th control value.
1587 If the specified value is not valid, it is ignored and prior one is kept.
1592 Apply a low-pass filter with 3dB point frequency.
1593 The filter can be either single-pole or double-pole (the default).
1594 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1596 The filter accepts the following options:
1600 Set frequency in Hz. Default is 500.
1603 Set number of poles. Default is 2.
1606 Set method to specify band-width of filter.
1619 Specify the band-width of a filter in width_type units.
1620 Applies only to double-pole filter.
1621 The default is 0.707q and gives a Butterworth response.
1626 Mix channels with specific gain levels. The filter accepts the output
1627 channel layout followed by a set of channels definitions.
1629 This filter is also designed to remap efficiently the channels of an audio
1632 The filter accepts parameters of the form:
1633 "@var{l}:@var{outdef}:@var{outdef}:..."
1637 output channel layout or number of channels
1640 output channel specification, of the form:
1641 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1644 output channel to define, either a channel name (FL, FR, etc.) or a channel
1645 number (c0, c1, etc.)
1648 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1651 input channel to use, see out_name for details; it is not possible to mix
1652 named and numbered input channels
1655 If the `=' in a channel specification is replaced by `<', then the gains for
1656 that specification will be renormalized so that the total is 1, thus
1657 avoiding clipping noise.
1659 @subsection Mixing examples
1661 For example, if you want to down-mix from stereo to mono, but with a bigger
1662 factor for the left channel:
1664 pan=1:c0=0.9*c0+0.1*c1
1667 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1668 7-channels surround:
1670 pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1673 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1674 that should be preferred (see "-ac" option) unless you have very specific
1677 @subsection Remapping examples
1679 The channel remapping will be effective if, and only if:
1682 @item gain coefficients are zeroes or ones,
1683 @item only one input per channel output,
1686 If all these conditions are satisfied, the filter will notify the user ("Pure
1687 channel mapping detected"), and use an optimized and lossless method to do the
1690 For example, if you have a 5.1 source and want a stereo audio stream by
1691 dropping the extra channels:
1693 pan="stereo: c0=FL : c1=FR"
1696 Given the same source, you can also switch front left and front right channels
1697 and keep the input channel layout:
1699 pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
1702 If the input is a stereo audio stream, you can mute the front left channel (and
1703 still keep the stereo channel layout) with:
1708 Still with a stereo audio stream input, you can copy the right channel in both
1709 front left and right:
1711 pan="stereo: c0=FR : c1=FR"
1716 ReplayGain scanner filter. This filter takes an audio stream as an input and
1717 outputs it unchanged.
1718 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1722 Convert the audio sample format, sample rate and channel layout. It is
1723 not meant to be used directly.
1725 @section silencedetect
1727 Detect silence in an audio stream.
1729 This filter logs a message when it detects that the input audio volume is less
1730 or equal to a noise tolerance value for a duration greater or equal to the
1731 minimum detected noise duration.
1733 The printed times and duration are expressed in seconds.
1735 The filter accepts the following options:
1739 Set silence duration until notification (default is 2 seconds).
1742 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1743 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1746 @subsection Examples
1750 Detect 5 seconds of silence with -50dB noise tolerance:
1752 silencedetect=n=-50dB:d=5
1756 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1757 tolerance in @file{silence.mp3}:
1759 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1765 Boost or cut treble (upper) frequencies of the audio using a two-pole
1766 shelving filter with a response similar to that of a standard
1767 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1769 The filter accepts the following options:
1773 Give the gain at whichever is the lower of ~22 kHz and the
1774 Nyquist frequency. Its useful range is about -20 (for a large cut)
1775 to +20 (for a large boost). Beware of clipping when using a positive gain.
1778 Set the filter's central frequency and so can be used
1779 to extend or reduce the frequency range to be boosted or cut.
1780 The default value is @code{3000} Hz.
1783 Set method to specify band-width of filter.
1796 Determine how steep is the filter's shelf transition.
1801 Adjust the input audio volume.
1803 It accepts the following parameters:
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 The default value for @var{volume} is "1.0".
1819 This parameter represents the mathematical precision.
1821 It determines which input sample formats will be allowed, which affects the
1822 precision of the volume scaling.
1826 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
1828 32-bit floating-point; this limits input sample format to FLT. (default)
1830 64-bit floating-point; this limits input sample format to DBL.
1834 Choose the 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 the track gain, if present.
1847 Prefer the album gain, if present.
1850 @item replaygain_preamp
1851 Pre-amplification gain in dB to apply to the selected replaygain gain.
1853 Default value for @var{replaygain_preamp} is 0.0.
1856 Set when the volume expression is evaluated.
1858 It accepts the following values:
1861 only evaluate expression once during the filter initialization, or
1862 when the @samp{volume} command is sent
1865 evaluate expression for each incoming frame
1868 Default value is @samp{once}.
1871 The volume expression can contain the following parameters.
1875 frame number (starting at zero)
1878 @item nb_consumed_samples
1879 number of samples consumed by the filter
1881 number of samples in the current frame
1883 original frame position in the file
1889 PTS at start of stream
1891 time at start of stream
1897 last set volume value
1900 Note that when @option{eval} is set to @samp{once} only the
1901 @var{sample_rate} and @var{tb} variables are available, all other
1902 variables will evaluate to NAN.
1904 @subsection Commands
1906 This filter supports the following commands:
1909 Modify the volume expression.
1910 The command accepts the same syntax of the corresponding option.
1912 If the specified expression is not valid, it is kept at its current
1914 @item replaygain_noclip
1915 Prevent clipping by limiting the gain applied.
1917 Default value for @var{replaygain_noclip} is 1.
1921 @subsection Examples
1925 Halve the input audio volume:
1929 volume=volume=-6.0206dB
1932 In all the above example the named key for @option{volume} can be
1933 omitted, for example like in:
1939 Increase input audio power by 6 decibels using fixed-point precision:
1941 volume=volume=6dB:precision=fixed
1945 Fade volume after time 10 with an annihilation period of 5 seconds:
1947 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
1951 @section volumedetect
1953 Detect the volume of the input video.
1955 The filter has no parameters. The input is not modified. Statistics about
1956 the volume will be printed in the log when the input stream end is reached.
1958 In particular it will show the mean volume (root mean square), maximum
1959 volume (on a per-sample basis), and the beginning of a histogram of the
1960 registered volume values (from the maximum value to a cumulated 1/1000 of
1963 All volumes are in decibels relative to the maximum PCM value.
1965 @subsection Examples
1967 Here is an excerpt of the output:
1969 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
1970 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
1971 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
1972 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
1973 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
1974 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
1975 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
1976 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
1977 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
1983 The mean square energy is approximately -27 dB, or 10^-2.7.
1985 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
1987 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
1990 In other words, raising the volume by +4 dB does not cause any clipping,
1991 raising it by +5 dB causes clipping for 6 samples, etc.
1993 @c man end AUDIO FILTERS
1995 @chapter Audio Sources
1996 @c man begin AUDIO SOURCES
1998 Below is a description of the currently available audio sources.
2002 Buffer audio frames, and make them available to the filter chain.
2004 This source is mainly intended for a programmatic use, in particular
2005 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2007 It accepts the following parameters:
2011 The timebase which will be used for timestamps of submitted frames. It must be
2012 either a floating-point number or in @var{numerator}/@var{denominator} form.
2015 The sample rate of the incoming audio buffers.
2018 The sample format of the incoming audio buffers.
2019 Either a sample format name or its corresponging integer representation from
2020 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2022 @item channel_layout
2023 The channel layout of the incoming audio buffers.
2024 Either a channel layout name from channel_layout_map in
2025 @file{libavutil/channel_layout.c} or its corresponding integer representation
2026 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2029 The number of channels of the incoming audio buffers.
2030 If both @var{channels} and @var{channel_layout} are specified, then they
2035 @subsection Examples
2038 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2041 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2042 Since the sample format with name "s16p" corresponds to the number
2043 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2046 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2051 Generate an audio signal specified by an expression.
2053 This source accepts in input one or more expressions (one for each
2054 channel), which are evaluated and used to generate a corresponding
2057 This source accepts the following options:
2061 Set the '|'-separated expressions list for each separate channel. In case the
2062 @option{channel_layout} option is not specified, the selected channel layout
2063 depends on the number of provided expressions. Otherwise the last
2064 specified expression is applied to the remaining output channels.
2066 @item channel_layout, c
2067 Set the channel layout. The number of channels in the specified layout
2068 must be equal to the number of specified expressions.
2071 Set the minimum duration of the sourced audio. See the function
2072 @code{av_parse_time()} for the accepted format.
2073 Note that the resulting duration may be greater than the specified
2074 duration, as the generated audio is always cut at the end of a
2077 If not specified, or the expressed duration is negative, the audio is
2078 supposed to be generated forever.
2081 Set the number of samples per channel per each output frame,
2084 @item sample_rate, s
2085 Specify the sample rate, default to 44100.
2088 Each expression in @var{exprs} can contain the following constants:
2092 number of the evaluated sample, starting from 0
2095 time of the evaluated sample expressed in seconds, starting from 0
2102 @subsection Examples
2112 Generate a sin signal with frequency of 440 Hz, set sample rate to
2115 aevalsrc="sin(440*2*PI*t):s=8000"
2119 Generate a two channels signal, specify the channel layout (Front
2120 Center + Back Center) explicitly:
2122 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2126 Generate white noise:
2128 aevalsrc="-2+random(0)"
2132 Generate an amplitude modulated signal:
2134 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2138 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2140 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2147 The null audio source, return unprocessed audio frames. It is mainly useful
2148 as a template and to be employed in analysis / debugging tools, or as
2149 the source for filters which ignore the input data (for example the sox
2152 This source accepts the following options:
2156 @item channel_layout, cl
2158 Specifies the channel layout, and can be either an integer or a string
2159 representing a channel layout. The default value of @var{channel_layout}
2162 Check the channel_layout_map definition in
2163 @file{libavutil/channel_layout.c} for the mapping between strings and
2164 channel layout values.
2166 @item sample_rate, r
2167 Specifies the sample rate, and defaults to 44100.
2170 Set the number of samples per requested frames.
2174 @subsection Examples
2178 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2180 anullsrc=r=48000:cl=4
2184 Do the same operation with a more obvious syntax:
2186 anullsrc=r=48000:cl=mono
2190 All the parameters need to be explicitly defined.
2194 Synthesize a voice utterance using the libflite library.
2196 To enable compilation of this filter you need to configure FFmpeg with
2197 @code{--enable-libflite}.
2199 Note that the flite library is not thread-safe.
2201 The filter accepts the following options:
2206 If set to 1, list the names of the available voices and exit
2207 immediately. Default value is 0.
2210 Set the maximum number of samples per frame. Default value is 512.
2213 Set the filename containing the text to speak.
2216 Set the text to speak.
2219 Set the voice to use for the speech synthesis. Default value is
2220 @code{kal}. See also the @var{list_voices} option.
2223 @subsection Examples
2227 Read from file @file{speech.txt}, and synthetize the text using the
2228 standard flite voice:
2230 flite=textfile=speech.txt
2234 Read the specified text selecting the @code{slt} voice:
2236 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2240 Input text to ffmpeg:
2242 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2246 Make @file{ffplay} speak the specified text, using @code{flite} and
2247 the @code{lavfi} device:
2249 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2253 For more information about libflite, check:
2254 @url{http://www.speech.cs.cmu.edu/flite/}
2258 Generate an audio signal made of a sine wave with amplitude 1/8.
2260 The audio signal is bit-exact.
2262 The filter accepts the following options:
2267 Set the carrier frequency. Default is 440 Hz.
2269 @item beep_factor, b
2270 Enable a periodic beep every second with frequency @var{beep_factor} times
2271 the carrier frequency. Default is 0, meaning the beep is disabled.
2273 @item sample_rate, r
2274 Specify the sample rate, default is 44100.
2277 Specify the duration of the generated audio stream.
2279 @item samples_per_frame
2280 Set the number of samples per output frame, default is 1024.
2283 @subsection Examples
2288 Generate a simple 440 Hz sine wave:
2294 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2298 sine=frequency=220:beep_factor=4:duration=5
2303 @c man end AUDIO SOURCES
2305 @chapter Audio Sinks
2306 @c man begin AUDIO SINKS
2308 Below is a description of the currently available audio sinks.
2310 @section abuffersink
2312 Buffer audio frames, and make them available to the end of filter chain.
2314 This sink is mainly intended for programmatic use, in particular
2315 through the interface defined in @file{libavfilter/buffersink.h}
2316 or the options system.
2318 It accepts a pointer to an AVABufferSinkContext structure, which
2319 defines the incoming buffers' formats, to be passed as the opaque
2320 parameter to @code{avfilter_init_filter} for initialization.
2323 Null audio sink; do absolutely nothing with the input audio. It is
2324 mainly useful as a template and for use in analysis / debugging
2327 @c man end AUDIO SINKS
2329 @chapter Video Filters
2330 @c man begin VIDEO FILTERS
2332 When you configure your FFmpeg build, you can disable any of the
2333 existing filters using @code{--disable-filters}.
2334 The configure output will show the video filters included in your
2337 Below is a description of the currently available video filters.
2339 @section alphaextract
2341 Extract the alpha component from the input as a grayscale video. This
2342 is especially useful with the @var{alphamerge} filter.
2346 Add or replace the alpha component of the primary input with the
2347 grayscale value of a second input. This is intended for use with
2348 @var{alphaextract} to allow the transmission or storage of frame
2349 sequences that have alpha in a format that doesn't support an alpha
2352 For example, to reconstruct full frames from a normal YUV-encoded video
2353 and a separate video created with @var{alphaextract}, you might use:
2355 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2358 Since this filter is designed for reconstruction, it operates on frame
2359 sequences without considering timestamps, and terminates when either
2360 input reaches end of stream. This will cause problems if your encoding
2361 pipeline drops frames. If you're trying to apply an image as an
2362 overlay to a video stream, consider the @var{overlay} filter instead.
2366 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2367 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2368 Substation Alpha) subtitles files.
2372 Compute the bounding box for the non-black pixels in the input frame
2375 This filter computes the bounding box containing all the pixels with a
2376 luminance value greater than the minimum allowed value.
2377 The parameters describing the bounding box are printed on the filter
2380 The filter accepts the following option:
2384 Set the minimal luminance value. Default is @code{16}.
2387 @section blackdetect
2389 Detect video intervals that are (almost) completely black. Can be
2390 useful to detect chapter transitions, commercials, or invalid
2391 recordings. Output lines contains the time for the start, end and
2392 duration of the detected black interval expressed in seconds.
2394 In order to display the output lines, you need to set the loglevel at
2395 least to the AV_LOG_INFO value.
2397 The filter accepts the following options:
2400 @item black_min_duration, d
2401 Set the minimum detected black duration expressed in seconds. It must
2402 be a non-negative floating point number.
2404 Default value is 2.0.
2406 @item picture_black_ratio_th, pic_th
2407 Set the threshold for considering a picture "black".
2408 Express the minimum value for the ratio:
2410 @var{nb_black_pixels} / @var{nb_pixels}
2413 for which a picture is considered black.
2414 Default value is 0.98.
2416 @item pixel_black_th, pix_th
2417 Set the threshold for considering a pixel "black".
2419 The threshold expresses the maximum pixel luminance value for which a
2420 pixel is considered "black". The provided value is scaled according to
2421 the following equation:
2423 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2426 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2427 the input video format, the range is [0-255] for YUV full-range
2428 formats and [16-235] for YUV non full-range formats.
2430 Default value is 0.10.
2433 The following example sets the maximum pixel threshold to the minimum
2434 value, and detects only black intervals of 2 or more seconds:
2436 blackdetect=d=2:pix_th=0.00
2441 Detect frames that are (almost) completely black. Can be useful to
2442 detect chapter transitions or commercials. Output lines consist of
2443 the frame number of the detected frame, the percentage of blackness,
2444 the position in the file if known or -1 and the timestamp in seconds.
2446 In order to display the output lines, you need to set the loglevel at
2447 least to the AV_LOG_INFO value.
2449 It accepts the following parameters:
2454 The percentage of the pixels that have to be below the threshold; it defaults to
2457 @item threshold, thresh
2458 The threshold below which a pixel value is considered black; it defaults to
2465 Blend two video frames into each other.
2467 It takes two input streams and outputs one stream, the first input is the
2468 "top" layer and second input is "bottom" layer.
2469 Output terminates when shortest input terminates.
2471 A description of the accepted options follows.
2479 Set blend mode for specific pixel component or all pixel components in case
2480 of @var{all_mode}. Default value is @code{normal}.
2482 Available values for component modes are:
2515 Set blend opacity for specific pixel component or all pixel components in case
2516 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2523 Set blend expression for specific pixel component or all pixel components in case
2524 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2526 The expressions can use the following variables:
2530 The sequential number of the filtered frame, starting from @code{0}.
2534 the coordinates of the current sample
2538 the width and height of currently filtered plane
2542 Width and height scale depending on the currently filtered plane. It is the
2543 ratio between the corresponding luma plane number of pixels and the current
2544 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2545 @code{0.5,0.5} for chroma planes.
2548 Time of the current frame, expressed in seconds.
2551 Value of pixel component at current location for first video frame (top layer).
2554 Value of pixel component at current location for second video frame (bottom layer).
2558 Force termination when the shortest input terminates. Default is @code{0}.
2560 Continue applying the last bottom frame after the end of the stream. A value of
2561 @code{0} disable the filter after the last frame of the bottom layer is reached.
2562 Default is @code{1}.
2565 @subsection Examples
2569 Apply transition from bottom layer to top layer in first 10 seconds:
2571 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2575 Apply 1x1 checkerboard effect:
2577 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2581 Apply uncover left effect:
2583 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2587 Apply uncover down effect:
2589 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2593 Apply uncover up-left effect:
2595 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2601 Apply a boxblur algorithm to the input video.
2603 It accepts the following parameters:
2607 @item luma_radius, lr
2608 @item luma_power, lp
2609 @item chroma_radius, cr
2610 @item chroma_power, cp
2611 @item alpha_radius, ar
2612 @item alpha_power, ap
2616 A description of the accepted options follows.
2619 @item luma_radius, lr
2620 @item chroma_radius, cr
2621 @item alpha_radius, ar
2622 Set an expression for the box radius in pixels used for blurring the
2623 corresponding input plane.
2625 The radius value must be a non-negative number, and must not be
2626 greater than the value of the expression @code{min(w,h)/2} for the
2627 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2630 Default value for @option{luma_radius} is "2". If not specified,
2631 @option{chroma_radius} and @option{alpha_radius} default to the
2632 corresponding value set for @option{luma_radius}.
2634 The expressions can contain the following constants:
2638 The input width and height in pixels.
2642 The input chroma image width and height in pixels.
2646 The horizontal and vertical chroma subsample values. For example, for the
2647 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
2650 @item luma_power, lp
2651 @item chroma_power, cp
2652 @item alpha_power, ap
2653 Specify how many times the boxblur filter is applied to the
2654 corresponding plane.
2656 Default value for @option{luma_power} is 2. If not specified,
2657 @option{chroma_power} and @option{alpha_power} default to the
2658 corresponding value set for @option{luma_power}.
2660 A value of 0 will disable the effect.
2663 @subsection Examples
2667 Apply a boxblur filter with the luma, chroma, and alpha radii
2670 boxblur=luma_radius=2:luma_power=1
2675 Set the luma radius to 2, and alpha and chroma radius to 0:
2677 boxblur=2:1:cr=0:ar=0
2681 Set the luma and chroma radii to a fraction of the video dimension:
2683 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2687 @section colorbalance
2688 Modify intensity of primary colors (red, green and blue) of input frames.
2690 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2691 regions for the red-cyan, green-magenta or blue-yellow balance.
2693 A positive adjustment value shifts the balance towards the primary color, a negative
2694 value towards the complementary color.
2696 The filter accepts the following options:
2702 Adjust red, green and blue shadows (darkest pixels).
2707 Adjust red, green and blue midtones (medium pixels).
2712 Adjust red, green and blue highlights (brightest pixels).
2714 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2717 @subsection Examples
2721 Add red color cast to shadows:
2727 @section colorchannelmixer
2729 Adjust video input frames by re-mixing color channels.
2731 This filter modifies a color channel by adding the values associated to
2732 the other channels of the same pixels. For example if the value to
2733 modify is red, the output value will be:
2735 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2738 The filter accepts the following options:
2745 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2746 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2752 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2753 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2759 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2760 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2766 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2767 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2769 Allowed ranges for options are @code{[-2.0, 2.0]}.
2772 @subsection Examples
2776 Convert source to grayscale:
2778 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2781 Simulate sepia tones:
2783 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
2787 @section colormatrix
2789 Convert color matrix.
2791 The filter accepts the following options:
2796 Specify the source and destination color matrix. Both values must be
2799 The accepted values are:
2815 For example to convert from BT.601 to SMPTE-240M, use the command:
2817 colormatrix=bt601:smpte240m
2822 Copy the input source unchanged to the output. This is mainly useful for
2827 Crop the input video to given dimensions.
2829 It accepts the following parameters:
2833 The width of the output video. It defaults to @code{iw}.
2834 This expression is evaluated only once during the filter
2838 The height of the output video. It defaults to @code{ih}.
2839 This expression is evaluated only once during the filter
2843 The horizontal position, in the input video, of the left edge of the output
2844 video. It defaults to @code{(in_w-out_w)/2}.
2845 This expression is evaluated per-frame.
2848 The vertical position, in the input video, of the top edge of the output video.
2849 It defaults to @code{(in_h-out_h)/2}.
2850 This expression is evaluated per-frame.
2853 If set to 1 will force the output display aspect ratio
2854 to be the same of the input, by changing the output sample aspect
2855 ratio. It defaults to 0.
2858 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
2859 expressions containing the following constants:
2864 The computed values for @var{x} and @var{y}. They are evaluated for
2869 The input width and height.
2873 These are the same as @var{in_w} and @var{in_h}.
2877 The output (cropped) width and height.
2881 These are the same as @var{out_w} and @var{out_h}.
2884 same as @var{iw} / @var{ih}
2887 input sample aspect ratio
2890 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
2894 horizontal and vertical chroma subsample values. For example for the
2895 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
2898 The number of the input frame, starting from 0.
2901 the position in the file of the input frame, NAN if unknown
2904 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
2908 The expression for @var{out_w} may depend on the value of @var{out_h},
2909 and the expression for @var{out_h} may depend on @var{out_w}, but they
2910 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
2911 evaluated after @var{out_w} and @var{out_h}.
2913 The @var{x} and @var{y} parameters specify the expressions for the
2914 position of the top-left corner of the output (non-cropped) area. They
2915 are evaluated for each frame. If the evaluated value is not valid, it
2916 is approximated to the nearest valid value.
2918 The expression for @var{x} may depend on @var{y}, and the expression
2919 for @var{y} may depend on @var{x}.
2921 @subsection Examples
2925 Crop area with size 100x100 at position (12,34).
2930 Using named options, the example above becomes:
2932 crop=w=100:h=100:x=12:y=34
2936 Crop the central input area with size 100x100:
2942 Crop the central input area with size 2/3 of the input video:
2944 crop=2/3*in_w:2/3*in_h
2948 Crop the input video central square:
2955 Delimit the rectangle with the top-left corner placed at position
2956 100:100 and the right-bottom corner corresponding to the right-bottom
2957 corner of the input image.
2959 crop=in_w-100:in_h-100:100:100
2963 Crop 10 pixels from the left and right borders, and 20 pixels from
2964 the top and bottom borders
2966 crop=in_w-2*10:in_h-2*20
2970 Keep only the bottom right quarter of the input image:
2972 crop=in_w/2:in_h/2:in_w/2:in_h/2
2976 Crop height for getting Greek harmony:
2978 crop=in_w:1/PHI*in_w
2982 Appply trembling effect:
2984 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)
2988 Apply erratic camera effect depending on timestamp:
2990 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)"
2994 Set x depending on the value of y:
2996 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3002 Auto-detect the crop size.
3004 It calculates the necessary cropping parameters and prints the
3005 recommended parameters via the logging system. The detected dimensions
3006 correspond to the non-black area of the input video.
3008 It accepts the following parameters:
3013 Set higher black value threshold, which can be optionally specified
3014 from nothing (0) to everything (255). An intensity value greater
3015 to the set value is considered non-black. It defaults to 24.
3018 The value which the width/height should be divisible by. It defaults to
3019 16. The offset is automatically adjusted to center the video. Use 2 to
3020 get only even dimensions (needed for 4:2:2 video). 16 is best when
3021 encoding to most video codecs.
3023 @item reset_count, reset
3024 Set the counter that determines after how many frames cropdetect will
3025 reset the previously detected largest video area and start over to
3026 detect the current optimal crop area. Default value is 0.
3028 This can be useful when channel logos distort the video area. 0
3029 indicates 'never reset', and returns the largest area encountered during
3036 Apply color adjustments using curves.
3038 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3039 component (red, green and blue) has its values defined by @var{N} key points
3040 tied from each other using a smooth curve. The x-axis represents the pixel
3041 values from the input frame, and the y-axis the new pixel values to be set for
3044 By default, a component curve is defined by the two points @var{(0;0)} and
3045 @var{(1;1)}. This creates a straight line where each original pixel value is
3046 "adjusted" to its own value, which means no change to the image.
3048 The filter allows you to redefine these two points and add some more. A new
3049 curve (using a natural cubic spline interpolation) will be define to pass
3050 smoothly through all these new coordinates. The new defined points needs to be
3051 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3052 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3053 the vector spaces, the values will be clipped accordingly.
3055 If there is no key point defined in @code{x=0}, the filter will automatically
3056 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3057 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3059 The filter accepts the following options:
3063 Select one of the available color presets. This option can be used in addition
3064 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3065 options takes priority on the preset values.
3066 Available presets are:
3069 @item color_negative
3072 @item increase_contrast
3074 @item linear_contrast
3075 @item medium_contrast
3077 @item strong_contrast
3080 Default is @code{none}.
3082 Set the master key points. These points will define a second pass mapping. It
3083 is sometimes called a "luminance" or "value" mapping. It can be used with
3084 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3085 post-processing LUT.
3087 Set the key points for the red component.
3089 Set the key points for the green component.
3091 Set the key points for the blue component.
3093 Set the key points for all components (not including master).
3094 Can be used in addition to the other key points component
3095 options. In this case, the unset component(s) will fallback on this
3096 @option{all} setting.
3098 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3101 To avoid some filtergraph syntax conflicts, each key points list need to be
3102 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3104 @subsection Examples
3108 Increase slightly the middle level of blue:
3110 curves=blue='0.5/0.58'
3116 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3118 Here we obtain the following coordinates for each components:
3121 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3123 @code{(0;0) (0.50;0.48) (1;1)}
3125 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3129 The previous example can also be achieved with the associated built-in preset:
3131 curves=preset=vintage
3141 Use a Photoshop preset and redefine the points of the green component:
3143 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3149 Denoise frames using 2D DCT (frequency domain filtering).
3151 This filter is not designed for real time and can be extremely slow.
3153 The filter accepts the following options:
3157 Set the noise sigma constant.
3159 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3160 coefficient (absolute value) below this threshold with be dropped.
3162 If you need a more advanced filtering, see @option{expr}.
3164 Default is @code{0}.
3167 Set number overlapping pixels for each block. Each block is of size
3168 @code{16x16}. Since the filter can be slow, you may want to reduce this value,
3169 at the cost of a less effective filter and the risk of various artefacts.
3171 If the overlapping value doesn't allow to process the whole input width or
3172 height, a warning will be displayed and according borders won't be denoised.
3174 Default value is @code{15}.
3177 Set the coefficient factor expression.
3179 For each coefficient of a DCT block, this expression will be evaluated as a
3180 multiplier value for the coefficient.
3182 If this is option is set, the @option{sigma} option will be ignored.
3184 The absolute value of the coefficient can be accessed through the @var{c}
3188 @subsection Examples
3190 Apply a denoise with a @option{sigma} of @code{4.5}:
3195 The same operation can be achieved using the expression system:
3197 dctdnoiz=e='gte(c, 4.5*3)'
3203 Drop duplicated frames at regular intervals.
3205 The filter accepts the following options:
3209 Set the number of frames from which one will be dropped. Setting this to
3210 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3211 Default is @code{5}.
3214 Set the threshold for duplicate detection. If the difference metric for a frame
3215 is less than or equal to this value, then it is declared as duplicate. Default
3219 Set scene change threshold. Default is @code{15}.
3223 Set the size of the x and y-axis blocks used during metric calculations.
3224 Larger blocks give better noise suppression, but also give worse detection of
3225 small movements. Must be a power of two. Default is @code{32}.
3228 Mark main input as a pre-processed input and activate clean source input
3229 stream. This allows the input to be pre-processed with various filters to help
3230 the metrics calculation while keeping the frame selection lossless. When set to
3231 @code{1}, the first stream is for the pre-processed input, and the second
3232 stream is the clean source from where the kept frames are chosen. Default is
3236 Set whether or not chroma is considered in the metric calculations. Default is
3242 Remove judder produced by partially interlaced telecined content.
3244 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3245 source was partially telecined content then the output of @code{pullup,dejudder}
3246 will have a variable frame rate. May change the recorded frame rate of the
3247 container. Aside from that change, this filter will not affect constant frame
3250 The option available in this filter is:
3254 Specify the length of the window over which the judder repeats.
3256 Accepts any interger greater than 1. Useful values are:
3260 If the original was telecined from 24 to 30 fps (Film to NTSC).
3263 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3266 If a mixture of the two.
3269 The default is @samp{4}.
3274 Suppress a TV station logo by a simple interpolation of the surrounding
3275 pixels. Just set a rectangle covering the logo and watch it disappear
3276 (and sometimes something even uglier appear - your mileage may vary).
3278 It accepts the following parameters:
3283 Specify the top left corner coordinates of the logo. They must be
3288 Specify the width and height of the logo to clear. They must be
3292 Specify the thickness of the fuzzy edge of the rectangle (added to
3293 @var{w} and @var{h}). The default value is 4.
3296 When set to 1, a green rectangle is drawn on the screen to simplify
3297 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3298 The default value is 0.
3300 The rectangle is drawn on the outermost pixels which will be (partly)
3301 replaced with interpolated values. The values of the next pixels
3302 immediately outside this rectangle in each direction will be used to
3303 compute the interpolated pixel values inside the rectangle.
3307 @subsection Examples
3311 Set a rectangle covering the area with top left corner coordinates 0,0
3312 and size 100x77, and a band of size 10:
3314 delogo=x=0:y=0:w=100:h=77:band=10
3321 Attempt to fix small changes in horizontal and/or vertical shift. This
3322 filter helps remove camera shake from hand-holding a camera, bumping a
3323 tripod, moving on a vehicle, etc.
3325 The filter accepts the following options:
3333 Specify a rectangular area where to limit the search for motion
3335 If desired the search for motion vectors can be limited to a
3336 rectangular area of the frame defined by its top left corner, width
3337 and height. These parameters have the same meaning as the drawbox
3338 filter which can be used to visualise the position of the bounding
3341 This is useful when simultaneous movement of subjects within the frame
3342 might be confused for camera motion by the motion vector search.
3344 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3345 then the full frame is used. This allows later options to be set
3346 without specifying the bounding box for the motion vector search.
3348 Default - search the whole frame.
3352 Specify the maximum extent of movement in x and y directions in the
3353 range 0-64 pixels. Default 16.
3356 Specify how to generate pixels to fill blanks at the edge of the
3357 frame. Available values are:
3360 Fill zeroes at blank locations
3362 Original image at blank locations
3364 Extruded edge value at blank locations
3366 Mirrored edge at blank locations
3368 Default value is @samp{mirror}.
3371 Specify the blocksize to use for motion search. Range 4-128 pixels,
3375 Specify the contrast threshold for blocks. Only blocks with more than
3376 the specified contrast (difference between darkest and lightest
3377 pixels) will be considered. Range 1-255, default 125.
3380 Specify the search strategy. Available values are:
3383 Set exhaustive search
3385 Set less exhaustive search.
3387 Default value is @samp{exhaustive}.
3390 If set then a detailed log of the motion search is written to the
3394 If set to 1, specify using OpenCL capabilities, only available if
3395 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3401 Draw a colored box on the input image.
3403 It accepts the following parameters:
3408 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3412 The expressions which specify the width and height of the box; if 0 they are interpreted as
3413 the input width and height. It defaults to 0.
3416 Specify the color of the box to write. For the general syntax of this option,
3417 check the "Color" section in the ffmpeg-utils manual. If the special
3418 value @code{invert} is used, the box edge color is the same as the
3419 video with inverted luma.
3422 The expression which sets the thickness of the box edge. Default value is @code{3}.
3424 See below for the list of accepted constants.
3427 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3428 following constants:
3432 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3436 horizontal and vertical chroma subsample values. For example for the
3437 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3441 The input width and height.
3444 The input sample aspect ratio.
3448 The x and y offset coordinates where the box is drawn.
3452 The width and height of the drawn box.
3455 The thickness of the drawn box.
3457 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3458 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3462 @subsection Examples
3466 Draw a black box around the edge of the input image:
3472 Draw a box with color red and an opacity of 50%:
3474 drawbox=10:20:200:60:red@@0.5
3477 The previous example can be specified as:
3479 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3483 Fill the box with pink color:
3485 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3489 Draw a 2-pixel red 2.40:1 mask:
3491 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
3497 Draw a grid on the input image.
3499 It accepts the following parameters:
3504 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3508 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3509 input width and height, respectively, minus @code{thickness}, so image gets
3510 framed. Default to 0.
3513 Specify the color of the grid. For the general syntax of this option,
3514 check the "Color" section in the ffmpeg-utils manual. If the special
3515 value @code{invert} is used, the grid color is the same as the
3516 video with inverted luma.
3519 The expression which sets the thickness of the grid line. Default value is @code{1}.
3521 See below for the list of accepted constants.
3524 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3525 following constants:
3529 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3533 horizontal and vertical chroma subsample values. For example for the
3534 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3538 The input grid cell width and height.
3541 The input sample aspect ratio.
3545 The x and y coordinates of some point of grid intersection (meant to configure offset).
3549 The width and height of the drawn cell.
3552 The thickness of the drawn cell.
3554 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3555 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3559 @subsection Examples
3563 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3565 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3569 Draw a white 3x3 grid with an opacity of 50%:
3571 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3578 Draw a text string or text from a specified file on top of a video, using the
3579 libfreetype library.
3581 To enable compilation of this filter, you need to configure FFmpeg with
3582 @code{--enable-libfreetype}.
3583 To enable default font fallback and the @var{font} option you need to
3584 configure FFmpeg with @code{--enable-libfontconfig}.
3588 It accepts the following parameters:
3593 Used to draw a box around text using the background color.
3594 The value must be either 1 (enable) or 0 (disable).
3595 The default value of @var{box} is 0.
3598 The color to be used for drawing box around text. For the syntax of this
3599 option, check the "Color" section in the ffmpeg-utils manual.
3601 The default value of @var{boxcolor} is "white".
3604 Set the width of the border to be drawn around the text using @var{bordercolor}.
3605 The default value of @var{borderw} is 0.
3608 Set the color to be used for drawing border around text. For the syntax of this
3609 option, check the "Color" section in the ffmpeg-utils manual.
3611 The default value of @var{bordercolor} is "black".
3614 Select how the @var{text} is expanded. Can be either @code{none},
3615 @code{strftime} (deprecated) or
3616 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3620 If true, check and fix text coords to avoid clipping.
3623 The color to be used for drawing fonts. For the syntax of this option, check
3624 the "Color" section in the ffmpeg-utils manual.
3626 The default value of @var{fontcolor} is "black".
3629 The font family to be used for drawing text. By default Sans.
3632 The font file to be used for drawing text. The path must be included.
3633 This parameter is mandatory if the fontconfig support is disabled.
3636 The font size to be used for drawing text.
3637 The default value of @var{fontsize} is 16.
3640 The flags to be used for loading the fonts.
3642 The flags map the corresponding flags supported by libfreetype, and are
3643 a combination of the following values:
3650 @item vertical_layout
3651 @item force_autohint
3654 @item ignore_global_advance_width
3656 @item ignore_transform
3662 Default value is "default".
3664 For more information consult the documentation for the FT_LOAD_*
3668 The color to be used for drawing a shadow behind the drawn text. For the
3669 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3671 The default value of @var{shadowcolor} is "black".
3675 The x and y offsets for the text shadow position with respect to the
3676 position of the text. They can be either positive or negative
3677 values. The default value for both is "0".
3680 The starting frame number for the n/frame_num variable. The default value
3684 The size in number of spaces to use for rendering the tab.
3688 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3689 format. It can be used with or without text parameter. @var{timecode_rate}
3690 option must be specified.
3692 @item timecode_rate, rate, r
3693 Set the timecode frame rate (timecode only).
3696 The text string to be drawn. The text must be a sequence of UTF-8
3698 This parameter is mandatory if no file is specified with the parameter
3702 A text file containing text to be drawn. The text must be a sequence
3703 of UTF-8 encoded characters.
3705 This parameter is mandatory if no text string is specified with the
3706 parameter @var{text}.
3708 If both @var{text} and @var{textfile} are specified, an error is thrown.
3711 If set to 1, the @var{textfile} will be reloaded before each frame.
3712 Be sure to update it atomically, or it may be read partially, or even fail.
3716 The expressions which specify the offsets where text will be drawn
3717 within the video frame. They are relative to the top/left border of the
3720 The default value of @var{x} and @var{y} is "0".
3722 See below for the list of accepted constants and functions.
3725 The parameters for @var{x} and @var{y} are expressions containing the
3726 following constants and functions:
3730 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3734 horizontal and vertical chroma subsample values. For example for the
3735 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3738 the height of each text line
3746 @item max_glyph_a, ascent
3747 the maximum distance from the baseline to the highest/upper grid
3748 coordinate used to place a glyph outline point, for all the rendered
3750 It is a positive value, due to the grid's orientation with the Y axis
3753 @item max_glyph_d, descent
3754 the maximum distance from the baseline to the lowest grid coordinate
3755 used to place a glyph outline point, for all the rendered glyphs.
3756 This is a negative value, due to the grid's orientation, with the Y axis
3760 maximum glyph height, that is the maximum height for all the glyphs
3761 contained in the rendered text, it is equivalent to @var{ascent} -
3765 maximum glyph width, that is the maximum width for all the glyphs
3766 contained in the rendered text
3769 the number of input frame, starting from 0
3771 @item rand(min, max)
3772 return a random number included between @var{min} and @var{max}
3775 The input sample aspect ratio.
3778 timestamp expressed in seconds, NAN if the input timestamp is unknown
3781 the height of the rendered text
3784 the width of the rendered text
3788 the x and y offset coordinates where the text is drawn.
3790 These parameters allow the @var{x} and @var{y} expressions to refer
3791 each other, so you can for example specify @code{y=x/dar}.
3794 @anchor{drawtext_expansion}
3795 @subsection Text expansion
3797 If @option{expansion} is set to @code{strftime},
3798 the filter recognizes strftime() sequences in the provided text and
3799 expands them accordingly. Check the documentation of strftime(). This
3800 feature is deprecated.
3802 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3804 If @option{expansion} is set to @code{normal} (which is the default),
3805 the following expansion mechanism is used.
3807 The backslash character '\', followed by any character, always expands to
3808 the second character.
3810 Sequence of the form @code{%@{...@}} are expanded. The text between the
3811 braces is a function name, possibly followed by arguments separated by ':'.
3812 If the arguments contain special characters or delimiters (':' or '@}'),
3813 they should be escaped.
3815 Note that they probably must also be escaped as the value for the
3816 @option{text} option in the filter argument string and as the filter
3817 argument in the filtergraph description, and possibly also for the shell,
3818 that makes up to four levels of escaping; using a text file avoids these
3821 The following functions are available:
3826 The expression evaluation result.
3828 It must take one argument specifying the expression to be evaluated,
3829 which accepts the same constants and functions as the @var{x} and
3830 @var{y} values. Note that not all constants should be used, for
3831 example the text size is not known when evaluating the expression, so
3832 the constants @var{text_w} and @var{text_h} will have an undefined
3836 The time at which the filter is running, expressed in UTC.
3837 It can accept an argument: a strftime() format string.
3840 The time at which the filter is running, expressed in the local time zone.
3841 It can accept an argument: a strftime() format string.
3844 Frame metadata. It must take one argument specifying metadata key.
3847 The frame number, starting from 0.
3850 A 1 character description of the current picture type.
3853 The timestamp of the current frame, in seconds, with microsecond accuracy.
3857 @subsection Examples
3861 Draw "Test Text" with font FreeSerif, using the default values for the
3862 optional parameters.
3865 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
3869 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
3870 and y=50 (counting from the top-left corner of the screen), text is
3871 yellow with a red box around it. Both the text and the box have an
3875 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
3876 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
3879 Note that the double quotes are not necessary if spaces are not used
3880 within the parameter list.
3883 Show the text at the center of the video frame:
3885 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
3889 Show a text line sliding from right to left in the last row of the video
3890 frame. The file @file{LONG_LINE} is assumed to contain a single line
3893 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
3897 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
3899 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
3903 Draw a single green letter "g", at the center of the input video.
3904 The glyph baseline is placed at half screen height.
3906 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
3910 Show text for 1 second every 3 seconds:
3912 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
3916 Use fontconfig to set the font. Note that the colons need to be escaped.
3918 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
3922 Print the date of a real-time encoding (see strftime(3)):
3924 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
3929 For more information about libfreetype, check:
3930 @url{http://www.freetype.org/}.
3932 For more information about fontconfig, check:
3933 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
3937 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
3939 The filter accepts the following options:
3944 Set low and high threshold values used by the Canny thresholding
3947 The high threshold selects the "strong" edge pixels, which are then
3948 connected through 8-connectivity with the "weak" edge pixels selected
3949 by the low threshold.
3951 @var{low} and @var{high} threshold values must be chosen in the range
3952 [0,1], and @var{low} should be lesser or equal to @var{high}.
3954 Default value for @var{low} is @code{20/255}, and default value for @var{high}
3960 edgedetect=low=0.1:high=0.4
3963 @section extractplanes
3965 Extract color channel components from input video stream into
3966 separate grayscale video streams.
3968 The filter accepts the following option:
3972 Set plane(s) to extract.
3974 Available values for planes are:
3985 Choosing planes not available in the input will result in an error.
3986 That means you cannot select @code{r}, @code{g}, @code{b} planes
3987 with @code{y}, @code{u}, @code{v} planes at same time.
3990 @subsection Examples
3994 Extract luma, u and v color channel component from input video frame
3995 into 3 grayscale outputs:
3997 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
4003 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4005 For each input image, the filter will compute the optimal mapping from
4006 the input to the output given the codebook length, that is the number
4007 of distinct output colors.
4009 This filter accepts the following options.
4012 @item codebook_length, l
4013 Set codebook length. The value must be a positive integer, and
4014 represents the number of distinct output colors. Default value is 256.
4017 Set the maximum number of iterations to apply for computing the optimal
4018 mapping. The higher the value the better the result and the higher the
4019 computation time. Default value is 1.
4022 Set a random seed, must be an integer included between 0 and
4023 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4024 will try to use a good random seed on a best effort basis.
4029 Apply a fade-in/out effect to the input video.
4031 It accepts the following parameters:
4035 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4037 Default is @code{in}.
4039 @item start_frame, s
4040 Specify the number of the frame to start applying the fade
4041 effect at. Default is 0.
4044 The number of frames that the fade effect lasts. At the end of the
4045 fade-in effect, the output video will have the same intensity as the input video.
4046 At the end of the fade-out transition, the output video will be filled with the
4047 selected @option{color}.
4051 If set to 1, fade only alpha channel, if one exists on the input.
4054 @item start_time, st
4055 Specify the timestamp (in seconds) of the frame to start to apply the fade
4056 effect. If both start_frame and start_time are specified, the fade will start at
4057 whichever comes last. Default is 0.
4060 The number of seconds for which the fade effect has to last. At the end of the
4061 fade-in effect the output video will have the same intensity as the input video,
4062 at the end of the fade-out transition the output video will be filled with the
4063 selected @option{color}.
4064 If both duration and nb_frames are specified, duration is used. Default is 0.
4067 Specify the color of the fade. Default is "black".
4070 @subsection Examples
4074 Fade in the first 30 frames of video:
4079 The command above is equivalent to:
4085 Fade out the last 45 frames of a 200-frame video:
4088 fade=type=out:start_frame=155:nb_frames=45
4092 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4094 fade=in:0:25, fade=out:975:25
4098 Make the first 5 frames yellow, then fade in from frame 5-24:
4100 fade=in:5:20:color=yellow
4104 Fade in alpha over first 25 frames of video:
4106 fade=in:0:25:alpha=1
4110 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4112 fade=t=in:st=5.5:d=0.5
4119 Extract a single field from an interlaced image using stride
4120 arithmetic to avoid wasting CPU time. The output frames are marked as
4123 The filter accepts the following options:
4127 Specify whether to extract the top (if the value is @code{0} or
4128 @code{top}) or the bottom field (if the value is @code{1} or
4134 Field matching filter for inverse telecine. It is meant to reconstruct the
4135 progressive frames from a telecined stream. The filter does not drop duplicated
4136 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4137 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4139 The separation of the field matching and the decimation is notably motivated by
4140 the possibility of inserting a de-interlacing filter fallback between the two.
4141 If the source has mixed telecined and real interlaced content,
4142 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4143 But these remaining combed frames will be marked as interlaced, and thus can be
4144 de-interlaced by a later filter such as @ref{yadif} before decimation.
4146 In addition to the various configuration options, @code{fieldmatch} can take an
4147 optional second stream, activated through the @option{ppsrc} option. If
4148 enabled, the frames reconstruction will be based on the fields and frames from
4149 this second stream. This allows the first input to be pre-processed in order to
4150 help the various algorithms of the filter, while keeping the output lossless
4151 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4152 or brightness/contrast adjustments can help.
4154 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4155 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4156 which @code{fieldmatch} is based on. While the semantic and usage are very
4157 close, some behaviour and options names can differ.
4159 The filter accepts the following options:
4163 Specify the assumed field order of the input stream. Available values are:
4167 Auto detect parity (use FFmpeg's internal parity value).
4169 Assume bottom field first.
4171 Assume top field first.
4174 Note that it is sometimes recommended not to trust the parity announced by the
4177 Default value is @var{auto}.
4180 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4181 sense that it won't risk creating jerkiness due to duplicate frames when
4182 possible, but if there are bad edits or blended fields it will end up
4183 outputting combed frames when a good match might actually exist. On the other
4184 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4185 but will almost always find a good frame if there is one. The other values are
4186 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4187 jerkiness and creating duplicate frames versus finding good matches in sections
4188 with bad edits, orphaned fields, blended fields, etc.
4190 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4192 Available values are:
4196 2-way matching (p/c)
4198 2-way matching, and trying 3rd match if still combed (p/c + n)
4200 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4202 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4203 still combed (p/c + n + u/b)
4205 3-way matching (p/c/n)
4207 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4208 detected as combed (p/c/n + u/b)
4211 The parenthesis at the end indicate the matches that would be used for that
4212 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4215 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4218 Default value is @var{pc_n}.
4221 Mark the main input stream as a pre-processed input, and enable the secondary
4222 input stream as the clean source to pick the fields from. See the filter
4223 introduction for more details. It is similar to the @option{clip2} feature from
4226 Default value is @code{0} (disabled).
4229 Set the field to match from. It is recommended to set this to the same value as
4230 @option{order} unless you experience matching failures with that setting. In
4231 certain circumstances changing the field that is used to match from can have a
4232 large impact on matching performance. Available values are:
4236 Automatic (same value as @option{order}).
4238 Match from the bottom field.
4240 Match from the top field.
4243 Default value is @var{auto}.
4246 Set whether or not chroma is included during the match comparisons. In most
4247 cases it is recommended to leave this enabled. You should set this to @code{0}
4248 only if your clip has bad chroma problems such as heavy rainbowing or other
4249 artifacts. Setting this to @code{0} could also be used to speed things up at
4250 the cost of some accuracy.
4252 Default value is @code{1}.
4256 These define an exclusion band which excludes the lines between @option{y0} and
4257 @option{y1} from being included in the field matching decision. An exclusion
4258 band can be used to ignore subtitles, a logo, or other things that may
4259 interfere with the matching. @option{y0} sets the starting scan line and
4260 @option{y1} sets the ending line; all lines in between @option{y0} and
4261 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4262 @option{y0} and @option{y1} to the same value will disable the feature.
4263 @option{y0} and @option{y1} defaults to @code{0}.
4266 Set the scene change detection threshold as a percentage of maximum change on
4267 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4268 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4269 @option{scthresh} is @code{[0.0, 100.0]}.
4271 Default value is @code{12.0}.
4274 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4275 account the combed scores of matches when deciding what match to use as the
4276 final match. Available values are:
4280 No final matching based on combed scores.
4282 Combed scores are only used when a scene change is detected.
4284 Use combed scores all the time.
4287 Default is @var{sc}.
4290 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4291 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4292 Available values are:
4296 No forced calculation.
4298 Force p/c/n calculations.
4300 Force p/c/n/u/b calculations.
4303 Default value is @var{none}.
4306 This is the area combing threshold used for combed frame detection. This
4307 essentially controls how "strong" or "visible" combing must be to be detected.
4308 Larger values mean combing must be more visible and smaller values mean combing
4309 can be less visible or strong and still be detected. Valid settings are from
4310 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4311 be detected as combed). This is basically a pixel difference value. A good
4312 range is @code{[8, 12]}.
4314 Default value is @code{9}.
4317 Sets whether or not chroma is considered in the combed frame decision. Only
4318 disable this if your source has chroma problems (rainbowing, etc.) that are
4319 causing problems for the combed frame detection with chroma enabled. Actually,
4320 using @option{chroma}=@var{0} is usually more reliable, except for the case
4321 where there is chroma only combing in the source.
4323 Default value is @code{0}.
4327 Respectively set the x-axis and y-axis size of the window used during combed
4328 frame detection. This has to do with the size of the area in which
4329 @option{combpel} pixels are required to be detected as combed for a frame to be
4330 declared combed. See the @option{combpel} parameter description for more info.
4331 Possible values are any number that is a power of 2 starting at 4 and going up
4334 Default value is @code{16}.
4337 The number of combed pixels inside any of the @option{blocky} by
4338 @option{blockx} size blocks on the frame for the frame to be detected as
4339 combed. While @option{cthresh} controls how "visible" the combing must be, this
4340 setting controls "how much" combing there must be in any localized area (a
4341 window defined by the @option{blockx} and @option{blocky} settings) on the
4342 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4343 which point no frames will ever be detected as combed). This setting is known
4344 as @option{MI} in TFM/VFM vocabulary.
4346 Default value is @code{80}.
4349 @anchor{p/c/n/u/b meaning}
4350 @subsection p/c/n/u/b meaning
4352 @subsubsection p/c/n
4354 We assume the following telecined stream:
4357 Top fields: 1 2 2 3 4
4358 Bottom fields: 1 2 3 4 4
4361 The numbers correspond to the progressive frame the fields relate to. Here, the
4362 first two frames are progressive, the 3rd and 4th are combed, and so on.
4364 When @code{fieldmatch} is configured to run a matching from bottom
4365 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4370 B 1 2 3 4 4 <-- matching reference
4379 As a result of the field matching, we can see that some frames get duplicated.
4380 To perform a complete inverse telecine, you need to rely on a decimation filter
4381 after this operation. See for instance the @ref{decimate} filter.
4383 The same operation now matching from top fields (@option{field}=@var{top})
4388 T 1 2 2 3 4 <-- matching reference
4398 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4399 basically, they refer to the frame and field of the opposite parity:
4402 @item @var{p} matches the field of the opposite parity in the previous frame
4403 @item @var{c} matches the field of the opposite parity in the current frame
4404 @item @var{n} matches the field of the opposite parity in the next frame
4409 The @var{u} and @var{b} matching are a bit special in the sense that they match
4410 from the opposite parity flag. In the following examples, we assume that we are
4411 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4412 'x' is placed above and below each matched fields.
4414 With bottom matching (@option{field}=@var{bottom}):
4419 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4420 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4428 With top matching (@option{field}=@var{top}):
4433 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4434 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4442 @subsection Examples
4444 Simple IVTC of a top field first telecined stream:
4446 fieldmatch=order=tff:combmatch=none, decimate
4449 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4451 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4456 Transform the field order of the input video.
4458 It accepts the following parameters:
4463 The output field order. Valid values are @var{tff} for top field first or @var{bff}
4464 for bottom field first.
4467 The default value is @samp{tff}.
4469 The transformation is done by shifting the picture content up or down
4470 by one line, and filling the remaining line with appropriate picture content.
4471 This method is consistent with most broadcast field order converters.
4473 If the input video is not flagged as being interlaced, or it is already
4474 flagged as being of the required output field order, then this filter does
4475 not alter the incoming video.
4477 It is very useful when converting to or from PAL DV material,
4478 which is bottom field first.
4482 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4487 Buffer input images and send them when they are requested.
4489 It is mainly useful when auto-inserted by the libavfilter
4492 It does not take parameters.
4497 Convert the input video to one of the specified pixel formats.
4498 Libavfilter will try to pick one that is suitable as input to
4501 It accepts the following parameters:
4505 A '|'-separated list of pixel format names, such as
4506 "pix_fmts=yuv420p|monow|rgb24".
4510 @subsection Examples
4514 Convert the input video to the @var{yuv420p} format
4516 format=pix_fmts=yuv420p
4519 Convert the input video to any of the formats in the list
4521 format=pix_fmts=yuv420p|yuv444p|yuv410p
4528 Convert the video to specified constant frame rate by duplicating or dropping
4529 frames as necessary.
4531 It accepts the following parameters:
4535 The desired output frame rate. The default is @code{25}.
4540 Possible values are:
4543 zero round towards 0
4547 round towards -infinity
4549 round towards +infinity
4553 The default is @code{near}.
4556 Assume the first PTS should be the given value, in seconds. This allows for
4557 padding/trimming at the start of stream. By default, no assumption is made
4558 about the first frame's expected PTS, so no padding or trimming is done.
4559 For example, this could be set to 0 to pad the beginning with duplicates of
4560 the first frame if a video stream starts after the audio stream or to trim any
4561 frames with a negative PTS.
4565 Alternatively, the options can be specified as a flat string:
4566 @var{fps}[:@var{round}].
4568 See also the @ref{setpts} filter.
4570 @subsection Examples
4574 A typical usage in order to set the fps to 25:
4580 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4582 fps=fps=film:round=near
4588 Pack two different video streams into a stereoscopic video, setting proper
4589 metadata on supported codecs. The two views should have the same size and
4590 framerate and processing will stop when the shorter video ends. Please note
4591 that you may conveniently adjust view properties with the @ref{scale} and
4594 It accepts the following parameters:
4598 The desired packing format. Supported values are:
4603 The views are next to each other (default).
4606 The views are on top of each other.
4609 The views are packed by line.
4612 The views are packed by column.
4615 The views are temporally interleaved.
4624 # Convert left and right views into a frame-sequential video
4625 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
4627 # Convert views into a side-by-side video with the same output resolution as the input
4628 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
4633 Select one frame every N-th frame.
4635 This filter accepts the following option:
4638 Select frame after every @code{step} frames.
4639 Allowed values are positive integers higher than 0. Default value is @code{1}.
4645 Apply a frei0r effect to the input video.
4647 To enable the compilation of this filter, you need to install the frei0r
4648 header and configure FFmpeg with @code{--enable-frei0r}.
4650 It accepts the following parameters:
4655 The name of the frei0r effect to load. If the environment variable
4656 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
4657 directories specified by the colon-separated list in @env{FREIOR_PATH}.
4658 Otherwise, the standard frei0r paths are searched, in this order:
4659 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
4660 @file{/usr/lib/frei0r-1/}.
4663 A '|'-separated list of parameters to pass to the frei0r effect.
4667 A frei0r effect parameter can be a boolean (its value is either
4668 "y" or "n"), a double, a color (specified as
4669 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
4670 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
4671 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
4672 @var{X} and @var{Y} are floating point numbers) and/or a string.
4674 The number and types of parameters depend on the loaded effect. If an
4675 effect parameter is not specified, the default value is set.
4677 @subsection Examples
4681 Apply the distort0r effect, setting the first two double parameters:
4683 frei0r=filter_name=distort0r:filter_params=0.5|0.01
4687 Apply the colordistance effect, taking a color as the first parameter:
4689 frei0r=colordistance:0.2/0.3/0.4
4690 frei0r=colordistance:violet
4691 frei0r=colordistance:0x112233
4695 Apply the perspective effect, specifying the top left and top right image
4698 frei0r=perspective:0.2/0.2|0.8/0.2
4702 For more information, see
4703 @url{http://frei0r.dyne.org}
4707 The filter accepts the following options:
4711 Set the luminance expression.
4713 Set the chrominance blue expression.
4715 Set the chrominance red expression.
4717 Set the alpha expression.
4719 Set the red expression.
4721 Set the green expression.
4723 Set the blue expression.
4726 The colorspace is selected according to the specified options. If one
4727 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4728 options is specified, the filter will automatically select a YCbCr
4729 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4730 @option{blue_expr} options is specified, it will select an RGB
4733 If one of the chrominance expression is not defined, it falls back on the other
4734 one. If no alpha expression is specified it will evaluate to opaque value.
4735 If none of chrominance expressions are specified, they will evaluate
4736 to the luminance expression.
4738 The expressions can use the following variables and functions:
4742 The sequential number of the filtered frame, starting from @code{0}.
4746 The coordinates of the current sample.
4750 The width and height of the image.
4754 Width and height scale depending on the currently filtered plane. It is the
4755 ratio between the corresponding luma plane number of pixels and the current
4756 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4757 @code{0.5,0.5} for chroma planes.
4760 Time of the current frame, expressed in seconds.
4763 Return the value of the pixel at location (@var{x},@var{y}) of the current
4767 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
4771 Return the value of the pixel at location (@var{x},@var{y}) of the
4772 blue-difference chroma plane. Return 0 if there is no such plane.
4775 Return the value of the pixel at location (@var{x},@var{y}) of the
4776 red-difference chroma plane. Return 0 if there is no such plane.
4781 Return the value of the pixel at location (@var{x},@var{y}) of the
4782 red/green/blue component. Return 0 if there is no such component.
4785 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
4786 plane. Return 0 if there is no such plane.
4789 For functions, if @var{x} and @var{y} are outside the area, the value will be
4790 automatically clipped to the closer edge.
4792 @subsection Examples
4796 Flip the image horizontally:
4802 Generate a bidimensional sine wave, with angle @code{PI/3} and a
4803 wavelength of 100 pixels:
4805 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
4809 Generate a fancy enigmatic moving light:
4811 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
4815 Generate a quick emboss effect:
4817 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
4821 Modify RGB components depending on pixel position:
4823 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
4829 Fix the banding artifacts that are sometimes introduced into nearly flat
4830 regions by truncation to 8bit color depth.
4831 Interpolate the gradients that should go where the bands are, and
4834 It is designed for playback only. Do not use it prior to
4835 lossy compression, because compression tends to lose the dither and
4836 bring back the bands.
4838 It accepts the following parameters:
4843 The maximum amount by which the filter will change any one pixel. This is also
4844 the threshold for detecting nearly flat regions. Acceptable values range from
4845 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
4849 The neighborhood to fit the gradient to. A larger radius makes for smoother
4850 gradients, but also prevents the filter from modifying the pixels near detailed
4851 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
4852 values will be clipped to the valid range.
4856 Alternatively, the options can be specified as a flat string:
4857 @var{strength}[:@var{radius}]
4859 @subsection Examples
4863 Apply the filter with a @code{3.5} strength and radius of @code{8}:
4869 Specify radius, omitting the strength (which will fall-back to the default
4880 Apply a Hald CLUT to a video stream.
4882 First input is the video stream to process, and second one is the Hald CLUT.
4883 The Hald CLUT input can be a simple picture or a complete video stream.
4885 The filter accepts the following options:
4889 Force termination when the shortest input terminates. Default is @code{0}.
4891 Continue applying the last CLUT after the end of the stream. A value of
4892 @code{0} disable the filter after the last frame of the CLUT is reached.
4893 Default is @code{1}.
4896 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
4897 filters share the same internals).
4899 More information about the Hald CLUT can be found on Eskil Steenberg's website
4900 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
4902 @subsection Workflow examples
4904 @subsubsection Hald CLUT video stream
4906 Generate an identity Hald CLUT stream altered with various effects:
4908 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
4911 Note: make sure you use a lossless codec.
4913 Then use it with @code{haldclut} to apply it on some random stream:
4915 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
4918 The Hald CLUT will be applied to the 10 first seconds (duration of
4919 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
4920 to the remaining frames of the @code{mandelbrot} stream.
4922 @subsubsection Hald CLUT with preview
4924 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
4925 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
4926 biggest possible square starting at the top left of the picture. The remaining
4927 padding pixels (bottom or right) will be ignored. This area can be used to add
4928 a preview of the Hald CLUT.
4930 Typically, the following generated Hald CLUT will be supported by the
4931 @code{haldclut} filter:
4934 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
4935 pad=iw+320 [padded_clut];
4936 smptebars=s=320x256, split [a][b];
4937 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
4938 [main][b] overlay=W-320" -frames:v 1 clut.png
4941 It contains the original and a preview of the effect of the CLUT: SMPTE color
4942 bars are displayed on the right-top, and below the same color bars processed by
4945 Then, the effect of this Hald CLUT can be visualized with:
4947 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
4952 Flip the input video horizontally.
4954 For example, to horizontally flip the input video with @command{ffmpeg}:
4956 ffmpeg -i in.avi -vf "hflip" out.avi
4960 This filter applies a global color histogram equalization on a
4963 It can be used to correct video that has a compressed range of pixel
4964 intensities. The filter redistributes the pixel intensities to
4965 equalize their distribution across the intensity range. It may be
4966 viewed as an "automatically adjusting contrast filter". This filter is
4967 useful only for correcting degraded or poorly captured source
4970 The filter accepts the following options:
4974 Determine the amount of equalization to be applied. As the strength
4975 is reduced, the distribution of pixel intensities more-and-more
4976 approaches that of the input frame. The value must be a float number
4977 in the range [0,1] and defaults to 0.200.
4980 Set the maximum intensity that can generated and scale the output
4981 values appropriately. The strength should be set as desired and then
4982 the intensity can be limited if needed to avoid washing-out. The value
4983 must be a float number in the range [0,1] and defaults to 0.210.
4986 Set the antibanding level. If enabled the filter will randomly vary
4987 the luminance of output pixels by a small amount to avoid banding of
4988 the histogram. Possible values are @code{none}, @code{weak} or
4989 @code{strong}. It defaults to @code{none}.
4994 Compute and draw a color distribution histogram for the input video.
4996 The computed histogram is a representation of the color component
4997 distribution in an image.
4999 The filter accepts the following options:
5005 It accepts the following values:
5008 Standard histogram that displays the color components distribution in an
5009 image. Displays color graph for each color component. Shows distribution of
5010 the Y, U, V, A or R, G, B components, depending on input format, in the
5011 current frame. Below each graph a color component scale meter is shown.
5014 Displays chroma values (U/V color placement) in a two dimensional
5015 graph (which is called a vectorscope). The brighter a pixel in the
5016 vectorscope, the more pixels of the input frame correspond to that pixel
5017 (i.e., more pixels have this chroma value). The V component is displayed on
5018 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5019 side being V = 255. The U component is displayed on the vertical (Y) axis,
5020 with the top representing U = 0 and the bottom representing U = 255.
5022 The position of a white pixel in the graph corresponds to the chroma value of
5023 a pixel of the input clip. The graph can therefore be used to read the hue
5024 (color flavor) and the saturation (the dominance of the hue in the color). As
5025 the hue of a color changes, it moves around the square. At the center of the
5026 square the saturation is zero, which means that the corresponding pixel has no
5027 color. If the amount of a specific color is increased (while leaving the other
5028 colors unchanged) the saturation increases, and the indicator moves towards
5029 the edge of the square.
5032 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5036 Per row/column color component graph. In row mode, the graph on the left side
5037 represents color component value 0 and the right side represents value = 255.
5038 In column mode, the top side represents color component value = 0 and bottom
5039 side represents value = 255.
5041 Default value is @code{levels}.
5044 Set height of level in @code{levels}. Default value is @code{200}.
5045 Allowed range is [50, 2048].
5048 Set height of color scale in @code{levels}. Default value is @code{12}.
5049 Allowed range is [0, 40].
5052 Set step for @code{waveform} mode. Smaller values are useful to find out how
5053 many values of the same luminance are distributed across input rows/columns.
5054 Default value is @code{10}. Allowed range is [1, 255].
5057 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5058 Default is @code{row}.
5060 @item waveform_mirror
5061 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5062 means mirrored. In mirrored mode, higher values will be represented on the left
5063 side for @code{row} mode and at the top for @code{column} mode. Default is
5064 @code{0} (unmirrored).
5067 Set display mode for @code{waveform} and @code{levels}.
5068 It accepts the following values:
5071 Display separate graph for the color components side by side in
5072 @code{row} waveform mode or one below the other in @code{column} waveform mode
5073 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5074 per color component graphs are placed below each other.
5076 Using this display mode in @code{waveform} histogram mode makes it easy to
5077 spot color casts in the highlights and shadows of an image, by comparing the
5078 contours of the top and the bottom graphs of each waveform. Since whites,
5079 grays, and blacks are characterized by exactly equal amounts of red, green,
5080 and blue, neutral areas of the picture should display three waveforms of
5081 roughly equal width/height. If not, the correction is easy to perform by
5082 making level adjustments the three waveforms.
5085 Presents information identical to that in the @code{parade}, except
5086 that the graphs representing color components are superimposed directly
5089 This display mode in @code{waveform} histogram mode makes it easier to spot
5090 relative differences or similarities in overlapping areas of the color
5091 components that are supposed to be identical, such as neutral whites, grays,
5094 Default is @code{parade}.
5097 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5098 Default is @code{linear}.
5101 @subsection Examples
5106 Calculate and draw histogram:
5108 ffplay -i input -vf histogram
5116 This is a high precision/quality 3d denoise filter. It aims to reduce
5117 image noise, producing smooth images and making still images really
5118 still. It should enhance compressibility.
5120 It accepts the following optional parameters:
5124 A non-negative floating point number which specifies spatial luma strength.
5127 @item chroma_spatial
5128 A non-negative floating point number which specifies spatial chroma strength.
5129 It defaults to 3.0*@var{luma_spatial}/4.0.
5132 A floating point number which specifies luma temporal strength. It defaults to
5133 6.0*@var{luma_spatial}/4.0.
5136 A floating point number which specifies chroma temporal strength. It defaults to
5137 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5142 Modify the hue and/or the saturation of the input.
5144 It accepts the following parameters:
5148 Specify the hue angle as a number of degrees. It accepts an expression,
5149 and defaults to "0".
5152 Specify the saturation in the [-10,10] range. It accepts an expression and
5156 Specify the hue angle as a number of radians. It accepts an
5157 expression, and defaults to "0".
5160 Specify the brightness in the [-10,10] range. It accepts an expression and
5164 @option{h} and @option{H} are mutually exclusive, and can't be
5165 specified at the same time.
5167 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5168 expressions containing the following constants:
5172 frame count of the input frame starting from 0
5175 presentation timestamp of the input frame expressed in time base units
5178 frame rate of the input video, NAN if the input frame rate is unknown
5181 timestamp expressed in seconds, NAN if the input timestamp is unknown
5184 time base of the input video
5187 @subsection Examples
5191 Set the hue to 90 degrees and the saturation to 1.0:
5197 Same command but expressing the hue in radians:
5203 Rotate hue and make the saturation swing between 0
5204 and 2 over a period of 1 second:
5206 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5210 Apply a 3 seconds saturation fade-in effect starting at 0:
5215 The general fade-in expression can be written as:
5217 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5221 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5223 hue="s=max(0\, min(1\, (8-t)/3))"
5226 The general fade-out expression can be written as:
5228 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5233 @subsection Commands
5235 This filter supports the following commands:
5241 Modify the hue and/or the saturation and/or brightness of the input video.
5242 The command accepts the same syntax of the corresponding option.
5244 If the specified expression is not valid, it is kept at its current
5250 Detect video interlacing type.
5252 This filter tries to detect if the input is interlaced or progressive,
5253 top or bottom field first.
5255 The filter accepts the following options:
5259 Set interlacing threshold.
5261 Set progressive threshold.
5266 Deinterleave or interleave fields.
5268 This filter allows one to process interlaced images fields without
5269 deinterlacing them. Deinterleaving splits the input frame into 2
5270 fields (so called half pictures). Odd lines are moved to the top
5271 half of the output image, even lines to the bottom half.
5272 You can process (filter) them independently and then re-interleave them.
5274 The filter accepts the following options:
5278 @item chroma_mode, c
5280 Available values for @var{luma_mode}, @var{chroma_mode} and
5281 @var{alpha_mode} are:
5287 @item deinterleave, d
5288 Deinterleave fields, placing one above the other.
5291 Interleave fields. Reverse the effect of deinterleaving.
5293 Default value is @code{none}.
5296 @item chroma_swap, cs
5297 @item alpha_swap, as
5298 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5303 Simple interlacing filter from progressive contents. This interleaves upper (or
5304 lower) lines from odd frames with lower (or upper) lines from even frames,
5305 halving the frame rate and preserving image height. A vertical lowpass filter
5306 is always applied in order to avoid twitter effects and reduce moiré patterns.
5309 Original Original New Frame
5310 Frame 'j' Frame 'j+1' (tff)
5311 ========== =========== ==================
5312 Line 0 --------------------> Frame 'j' Line 0
5313 Line 1 Line 1 ----> Frame 'j+1' Line 1
5314 Line 2 ---------------------> Frame 'j' Line 2
5315 Line 3 Line 3 ----> Frame 'j+1' Line 3
5317 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5320 It accepts the following optional parameters:
5324 This determines whether the interlaced frame is taken from the even
5325 (tff - default) or odd (bff) lines of the progressive frame.
5330 Deinterlace input video by applying Donald Graft's adaptive kernel
5331 deinterling. Work on interlaced parts of a video to produce
5334 The description of the accepted parameters follows.
5338 Set the threshold which affects the filter's tolerance when
5339 determining if a pixel line must be processed. It must be an integer
5340 in the range [0,255] and defaults to 10. A value of 0 will result in
5341 applying the process on every pixels.
5344 Paint pixels exceeding the threshold value to white if set to 1.
5348 Set the fields order. Swap fields if set to 1, leave fields alone if
5352 Enable additional sharpening if set to 1. Default is 0.
5355 Enable twoway sharpening if set to 1. Default is 0.
5358 @subsection Examples
5362 Apply default values:
5364 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5368 Enable additional sharpening:
5374 Paint processed pixels in white:
5383 Apply a 3D LUT to an input video.
5385 The filter accepts the following options:
5389 Set the 3D LUT file name.
5391 Currently supported formats:
5403 Select interpolation mode.
5405 Available values are:
5409 Use values from the nearest defined point.
5411 Interpolate values using the 8 points defining a cube.
5413 Interpolate values using a tetrahedron.
5417 @section lut, lutrgb, lutyuv
5419 Compute a look-up table for binding each pixel component input value
5420 to an output value, and apply it to the input video.
5422 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5423 to an RGB input video.
5425 These filters accept the following parameters:
5428 set first pixel component expression
5430 set second pixel component expression
5432 set third pixel component expression
5434 set fourth pixel component expression, corresponds to the alpha component
5437 set red component expression
5439 set green component expression
5441 set blue component expression
5443 alpha component expression
5446 set Y/luminance component expression
5448 set U/Cb component expression
5450 set V/Cr component expression
5453 Each of them specifies the expression to use for computing the lookup table for
5454 the corresponding pixel component values.
5456 The exact component associated to each of the @var{c*} options depends on the
5459 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5460 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5462 The expressions can contain the following constants and functions:
5467 The input width and height.
5470 The input value for the pixel component.
5473 The input value, clipped to the @var{minval}-@var{maxval} range.
5476 The maximum value for the pixel component.
5479 The minimum value for the pixel component.
5482 The negated value for the pixel component value, clipped to the
5483 @var{minval}-@var{maxval} range; it corresponds to the expression
5484 "maxval-clipval+minval".
5487 The computed value in @var{val}, clipped to the
5488 @var{minval}-@var{maxval} range.
5490 @item gammaval(gamma)
5491 The computed gamma correction value of the pixel component value,
5492 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
5494 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
5498 All expressions default to "val".
5500 @subsection Examples
5506 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
5507 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
5510 The above is the same as:
5512 lutrgb="r=negval:g=negval:b=negval"
5513 lutyuv="y=negval:u=negval:v=negval"
5523 Remove chroma components, turning the video into a graytone image:
5525 lutyuv="u=128:v=128"
5529 Apply a luma burning effect:
5535 Remove green and blue components:
5541 Set a constant alpha channel value on input:
5543 format=rgba,lutrgb=a="maxval-minval/2"
5547 Correct luminance gamma by a factor of 0.5:
5549 lutyuv=y=gammaval(0.5)
5553 Discard least significant bits of luma:
5555 lutyuv=y='bitand(val, 128+64+32)'
5559 @section mergeplanes
5561 Merge color channel components from several video streams.
5563 The filter accepts up to 4 input streams, and merge selected input
5564 planes to the output video.
5566 This filter accepts the following options:
5569 Set input to output plane mapping. Default is @code{0}.
5571 The mappings is specified as a bitmap. It should be specified as a
5572 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
5573 mapping for the first plane of the output stream. 'A' sets the number of
5574 the input stream to use (from 0 to 3), and 'a' the plane number of the
5575 corresponding input to use (from 0 to 3). The rest of the mappings is
5576 similar, 'Bb' describes the mapping for the output stream second
5577 plane, 'Cc' describes the mapping for the output stream third plane and
5578 'Dd' describes the mapping for the output stream fourth plane.
5581 Set output pixel format. Default is @code{yuva444p}.
5584 @subsection Examples
5588 Merge three gray video streams of same width and height into single video stream:
5590 [a0][a1][a2]mergeplanes=0x001020:yuv444p
5594 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
5596 [a0][a1]mergeplanes=0x00010210:yuva444p
5600 Swap Y and A plane in yuva444p stream:
5602 format=yuva444p,mergeplanes=0x03010200:yuva444p
5606 Swap U and V plane in yuv420p stream:
5608 format=yuv420p,mergeplanes=0x000201:yuv420p
5612 Cast a rgb24 clip to yuv444p:
5614 format=rgb24,mergeplanes=0x000102:yuv444p
5620 Apply motion-compensation deinterlacing.
5622 It needs one field per frame as input and must thus be used together
5623 with yadif=1/3 or equivalent.
5625 This filter accepts the following options:
5628 Set the deinterlacing mode.
5630 It accepts one of the following values:
5635 use iterative motion estimation
5637 like @samp{slow}, but use multiple reference frames.
5639 Default value is @samp{fast}.
5642 Set the picture field parity assumed for the input video. It must be
5643 one of the following values:
5647 assume top field first
5649 assume bottom field first
5652 Default value is @samp{bff}.
5655 Set per-block quantization parameter (QP) used by the internal
5658 Higher values should result in a smoother motion vector field but less
5659 optimal individual vectors. Default value is 1.
5664 Apply an MPlayer filter to the input video.
5666 This filter provides a wrapper around some of the filters of
5669 This wrapper is considered experimental. Some of the wrapped filters
5670 may not work properly and we may drop support for them, as they will
5671 be implemented natively into FFmpeg. Thus you should avoid
5672 depending on them when writing portable scripts.
5674 The filter accepts the parameters:
5675 @var{filter_name}[:=]@var{filter_params}
5677 @var{filter_name} is the name of a supported MPlayer filter,
5678 @var{filter_params} is a string containing the parameters accepted by
5681 The list of the currently supported filters follows:
5692 The parameter syntax and behavior for the listed filters are the same
5693 of the corresponding MPlayer filters. For detailed instructions check
5694 the "VIDEO FILTERS" section in the MPlayer manual.
5696 @subsection Examples
5700 Adjust gamma, brightness, contrast:
5706 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
5710 Drop frames that do not differ greatly from the previous frame in
5711 order to reduce frame rate.
5713 The main use of this filter is for very-low-bitrate encoding
5714 (e.g. streaming over dialup modem), but it could in theory be used for
5715 fixing movies that were inverse-telecined incorrectly.
5717 A description of the accepted options follows.
5721 Set the maximum number of consecutive frames which can be dropped (if
5722 positive), or the minimum interval between dropped frames (if
5723 negative). If the value is 0, the frame is dropped unregarding the
5724 number of previous sequentially dropped frames.
5731 Set the dropping threshold values.
5733 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
5734 represent actual pixel value differences, so a threshold of 64
5735 corresponds to 1 unit of difference for each pixel, or the same spread
5736 out differently over the block.
5738 A frame is a candidate for dropping if no 8x8 blocks differ by more
5739 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
5740 meaning the whole image) differ by more than a threshold of @option{lo}.
5742 Default value for @option{hi} is 64*12, default value for @option{lo} is
5743 64*5, and default value for @option{frac} is 0.33.
5751 It accepts an integer in input; if non-zero it negates the
5752 alpha component (if available). The default value in input is 0.
5756 Force libavfilter not to use any of the specified pixel formats for the
5757 input to the next filter.
5759 It accepts the following parameters:
5763 A '|'-separated list of pixel format names, such as
5764 apix_fmts=yuv420p|monow|rgb24".
5768 @subsection Examples
5772 Force libavfilter to use a format different from @var{yuv420p} for the
5773 input to the vflip filter:
5775 noformat=pix_fmts=yuv420p,vflip
5779 Convert the input video to any of the formats not contained in the list:
5781 noformat=yuv420p|yuv444p|yuv410p
5787 Add noise on video input frame.
5789 The filter accepts the following options:
5797 Set noise seed for specific pixel component or all pixel components in case
5798 of @var{all_seed}. Default value is @code{123457}.
5800 @item all_strength, alls
5801 @item c0_strength, c0s
5802 @item c1_strength, c1s
5803 @item c2_strength, c2s
5804 @item c3_strength, c3s
5805 Set noise strength for specific pixel component or all pixel components in case
5806 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
5808 @item all_flags, allf
5813 Set pixel component flags or set flags for all components if @var{all_flags}.
5814 Available values for component flags are:
5817 averaged temporal noise (smoother)
5819 mix random noise with a (semi)regular pattern
5821 temporal noise (noise pattern changes between frames)
5823 uniform noise (gaussian otherwise)
5827 @subsection Examples
5829 Add temporal and uniform noise to input video:
5831 noise=alls=20:allf=t+u
5836 Pass the video source unchanged to the output.
5840 Apply a video transform using libopencv.
5842 To enable this filter, install the libopencv library and headers and
5843 configure FFmpeg with @code{--enable-libopencv}.
5845 It accepts the following parameters:
5850 The name of the libopencv filter to apply.
5853 The parameters to pass to the libopencv filter. If not specified, the default
5858 Refer to the official libopencv documentation for more precise
5860 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
5862 Several libopencv filters are supported; see the following subsections.
5867 Dilate an image by using a specific structuring element.
5868 It corresponds to the libopencv function @code{cvDilate}.
5870 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
5872 @var{struct_el} represents a structuring element, and has the syntax:
5873 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
5875 @var{cols} and @var{rows} represent the number of columns and rows of
5876 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
5877 point, and @var{shape} the shape for the structuring element. @var{shape}
5878 must be "rect", "cross", "ellipse", or "custom".
5880 If the value for @var{shape} is "custom", it must be followed by a
5881 string of the form "=@var{filename}". The file with name
5882 @var{filename} is assumed to represent a binary image, with each
5883 printable character corresponding to a bright pixel. When a custom
5884 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
5885 or columns and rows of the read file are assumed instead.
5887 The default value for @var{struct_el} is "3x3+0x0/rect".
5889 @var{nb_iterations} specifies the number of times the transform is
5890 applied to the image, and defaults to 1.
5894 # Use the default values
5897 # Dilate using a structuring element with a 5x5 cross, iterating two times
5898 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
5900 # Read the shape from the file diamond.shape, iterating two times.
5901 # The file diamond.shape may contain a pattern of characters like this
5907 # The specified columns and rows are ignored
5908 # but the anchor point coordinates are not
5909 ocv=dilate:0x0+2x2/custom=diamond.shape|2
5914 Erode an image by using a specific structuring element.
5915 It corresponds to the libopencv function @code{cvErode}.
5917 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
5918 with the same syntax and semantics as the @ref{dilate} filter.
5922 Smooth the input video.
5924 The filter takes the following parameters:
5925 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
5927 @var{type} is the type of smooth filter to apply, and must be one of
5928 the following values: "blur", "blur_no_scale", "median", "gaussian",
5929 or "bilateral". The default value is "gaussian".
5931 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
5932 depend on the smooth type. @var{param1} and
5933 @var{param2} accept integer positive values or 0. @var{param3} and
5934 @var{param4} accept floating point values.
5936 The default value for @var{param1} is 3. The default value for the
5937 other parameters is 0.
5939 These parameters correspond to the parameters assigned to the
5940 libopencv function @code{cvSmooth}.
5945 Overlay one video on top of another.
5947 It takes two inputs and has one output. The first input is the "main"
5948 video on which the second input is overlayed.
5950 It accepts the following parameters:
5952 A description of the accepted options follows.
5957 Set the expression for the x and y coordinates of the overlayed video
5958 on the main video. Default value is "0" for both expressions. In case
5959 the expression is invalid, it is set to a huge value (meaning that the
5960 overlay will not be displayed within the output visible area).
5963 The action to take when EOF is encountered on the secondary input; it accepts
5964 one of the following values:
5968 Repeat the last frame (the default).
5972 Pass the main input through.
5976 Set when the expressions for @option{x}, and @option{y} are evaluated.
5978 It accepts the following values:
5981 only evaluate expressions once during the filter initialization or
5982 when a command is processed
5985 evaluate expressions for each incoming frame
5988 Default value is @samp{frame}.
5991 If set to 1, force the output to terminate when the shortest input
5992 terminates. Default value is 0.
5995 Set the format for the output video.
5997 It accepts the following values:
6012 Default value is @samp{yuv420}.
6014 @item rgb @emph{(deprecated)}
6015 If set to 1, force the filter to accept inputs in the RGB
6016 color space. Default value is 0. This option is deprecated, use
6017 @option{format} instead.
6020 If set to 1, force the filter to draw the last overlay frame over the
6021 main input until the end of the stream. A value of 0 disables this
6022 behavior. Default value is 1.
6025 The @option{x}, and @option{y} expressions can contain the following
6031 The main input width and height.
6035 The overlay input width and height.
6039 The computed values for @var{x} and @var{y}. They are evaluated for
6044 horizontal and vertical chroma subsample values of the output
6045 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6049 the number of input frame, starting from 0
6052 the position in the file of the input frame, NAN if unknown
6055 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6059 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6060 when evaluation is done @emph{per frame}, and will evaluate to NAN
6061 when @option{eval} is set to @samp{init}.
6063 Be aware that frames are taken from each input video in timestamp
6064 order, hence, if their initial timestamps differ, it is a good idea
6065 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6066 have them begin in the same zero timestamp, as the example for
6067 the @var{movie} filter does.
6069 You can chain together more overlays but you should test the
6070 efficiency of such approach.
6072 @subsection Commands
6074 This filter supports the following commands:
6078 Modify the x and y of the overlay input.
6079 The command accepts the same syntax of the corresponding option.
6081 If the specified expression is not valid, it is kept at its current
6085 @subsection Examples
6089 Draw the overlay at 10 pixels from the bottom right corner of the main
6092 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6095 Using named options the example above becomes:
6097 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6101 Insert a transparent PNG logo in the bottom left corner of the input,
6102 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6104 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6108 Insert 2 different transparent PNG logos (second logo on bottom
6109 right corner) using the @command{ffmpeg} tool:
6111 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
6115 Add a transparent color layer on top of the main video; @code{WxH}
6116 must specify the size of the main input to the overlay filter:
6118 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6122 Play an original video and a filtered version (here with the deshake
6123 filter) side by side using the @command{ffplay} tool:
6125 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6128 The above command is the same as:
6130 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6134 Make a sliding overlay appearing from the left to the right top part of the
6135 screen starting since time 2:
6137 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6141 Compose output by putting two input videos side to side:
6143 ffmpeg -i left.avi -i right.avi -filter_complex "
6144 nullsrc=size=200x100 [background];
6145 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6146 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6147 [background][left] overlay=shortest=1 [background+left];
6148 [background+left][right] overlay=shortest=1:x=100 [left+right]
6153 Mask 10-20 seconds of a video by applying the delogo filter to a section
6155 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6156 -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]'
6161 Chain several overlays in cascade:
6163 nullsrc=s=200x200 [bg];
6164 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6165 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6166 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6167 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6168 [in3] null, [mid2] overlay=100:100 [out0]
6175 Apply Overcomplete Wavelet denoiser.
6177 The filter accepts the following options:
6183 Larger depth values will denoise lower frequency components more, but
6184 slow down filtering.
6186 Must be an int in the range 8-16, default is @code{8}.
6188 @item luma_strength, ls
6191 Must be a double value in the range 0-1000, default is @code{1.0}.
6193 @item chroma_strength, cs
6194 Set chroma strength.
6196 Must be a double value in the range 0-1000, default is @code{1.0}.
6201 Add paddings to the input image, and place the original input at the
6202 provided @var{x}, @var{y} coordinates.
6204 It accepts the following parameters:
6209 Specify an expression for the size of the output image with the
6210 paddings added. If the value for @var{width} or @var{height} is 0, the
6211 corresponding input size is used for the output.
6213 The @var{width} expression can reference the value set by the
6214 @var{height} expression, and vice versa.
6216 The default value of @var{width} and @var{height} is 0.
6220 Specify the offsets to place the input image at within the padded area,
6221 with respect to the top/left border of the output image.
6223 The @var{x} expression can reference the value set by the @var{y}
6224 expression, and vice versa.
6226 The default value of @var{x} and @var{y} is 0.
6229 Specify the color of the padded area. For the syntax of this option,
6230 check the "Color" section in the ffmpeg-utils manual.
6232 The default value of @var{color} is "black".
6235 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6236 options are expressions containing the following constants:
6241 The input video width and height.
6245 These are the same as @var{in_w} and @var{in_h}.
6249 The output width and height (the size of the padded area), as
6250 specified by the @var{width} and @var{height} expressions.
6254 These are the same as @var{out_w} and @var{out_h}.
6258 The x and y offsets as specified by the @var{x} and @var{y}
6259 expressions, or NAN if not yet specified.
6262 same as @var{iw} / @var{ih}
6265 input sample aspect ratio
6268 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6272 The horizontal and vertical chroma subsample values. For example for the
6273 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6276 @subsection Examples
6280 Add paddings with the color "violet" to the input video. The output video
6281 size is 640x480, and the top-left corner of the input video is placed at
6284 pad=640:480:0:40:violet
6287 The example above is equivalent to the following command:
6289 pad=width=640:height=480:x=0:y=40:color=violet
6293 Pad the input to get an output with dimensions increased by 3/2,
6294 and put the input video at the center of the padded area:
6296 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6300 Pad the input to get a squared output with size equal to the maximum
6301 value between the input width and height, and put the input video at
6302 the center of the padded area:
6304 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6308 Pad the input to get a final w/h ratio of 16:9:
6310 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6314 In case of anamorphic video, in order to set the output display aspect
6315 correctly, it is necessary to use @var{sar} in the expression,
6316 according to the relation:
6318 (ih * X / ih) * sar = output_dar
6319 X = output_dar / sar
6322 Thus the previous example needs to be modified to:
6324 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6328 Double the output size and put the input video in the bottom-right
6329 corner of the output padded area:
6331 pad="2*iw:2*ih:ow-iw:oh-ih"
6335 @section perspective
6337 Correct perspective of video not recorded perpendicular to the screen.
6339 A description of the accepted parameters follows.
6350 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6351 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6353 The expressions can use the following variables:
6358 the width and height of video frame.
6362 Set interpolation for perspective correction.
6364 It accepts the following values:
6370 Default value is @samp{linear}.
6375 Delay interlaced video by one field time so that the field order changes.
6377 The intended use is to fix PAL movies that have been captured with the
6378 opposite field order to the film-to-video transfer.
6380 A description of the accepted parameters follows.
6386 It accepts the following values:
6389 Capture field order top-first, transfer bottom-first.
6390 Filter will delay the bottom field.
6393 Capture field order bottom-first, transfer top-first.
6394 Filter will delay the top field.
6397 Capture and transfer with the same field order. This mode only exists
6398 for the documentation of the other options to refer to, but if you
6399 actually select it, the filter will faithfully do nothing.
6402 Capture field order determined automatically by field flags, transfer
6404 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6405 basis using field flags. If no field information is available,
6406 then this works just like @samp{u}.
6409 Capture unknown or varying, transfer opposite.
6410 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6411 analyzing the images and selecting the alternative that produces best
6412 match between the fields.
6415 Capture top-first, transfer unknown or varying.
6416 Filter selects among @samp{t} and @samp{p} using image analysis.
6419 Capture bottom-first, transfer unknown or varying.
6420 Filter selects among @samp{b} and @samp{p} using image analysis.
6423 Capture determined by field flags, transfer unknown or varying.
6424 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6425 image analysis. If no field information is available, then this works just
6426 like @samp{U}. This is the default mode.
6429 Both capture and transfer unknown or varying.
6430 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
6434 @section pixdesctest
6436 Pixel format descriptor test filter, mainly useful for internal
6437 testing. The output video should be equal to the input video.
6441 format=monow, pixdesctest
6444 can be used to test the monowhite pixel format descriptor definition.
6448 Enable the specified chain of postprocessing subfilters using libpostproc. This
6449 library should be automatically selected with a GPL build (@code{--enable-gpl}).
6450 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
6451 Each subfilter and some options have a short and a long name that can be used
6452 interchangeably, i.e. dr/dering are the same.
6454 The filters accept the following options:
6458 Set postprocessing subfilters string.
6461 All subfilters share common options to determine their scope:
6465 Honor the quality commands for this subfilter.
6468 Do chrominance filtering, too (default).
6471 Do luminance filtering only (no chrominance).
6474 Do chrominance filtering only (no luminance).
6477 These options can be appended after the subfilter name, separated by a '|'.
6479 Available subfilters are:
6482 @item hb/hdeblock[|difference[|flatness]]
6483 Horizontal deblocking filter
6486 Difference factor where higher values mean more deblocking (default: @code{32}).
6488 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6491 @item vb/vdeblock[|difference[|flatness]]
6492 Vertical deblocking filter
6495 Difference factor where higher values mean more deblocking (default: @code{32}).
6497 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6500 @item ha/hadeblock[|difference[|flatness]]
6501 Accurate horizontal deblocking filter
6504 Difference factor where higher values mean more deblocking (default: @code{32}).
6506 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6509 @item va/vadeblock[|difference[|flatness]]
6510 Accurate vertical deblocking filter
6513 Difference factor where higher values mean more deblocking (default: @code{32}).
6515 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6519 The horizontal and vertical deblocking filters share the difference and
6520 flatness values so you cannot set different horizontal and vertical
6525 Experimental horizontal deblocking filter
6528 Experimental vertical deblocking filter
6533 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
6536 larger -> stronger filtering
6538 larger -> stronger filtering
6540 larger -> stronger filtering
6543 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
6546 Stretch luminance to @code{0-255}.
6549 @item lb/linblenddeint
6550 Linear blend deinterlacing filter that deinterlaces the given block by
6551 filtering all lines with a @code{(1 2 1)} filter.
6553 @item li/linipoldeint
6554 Linear interpolating deinterlacing filter that deinterlaces the given block by
6555 linearly interpolating every second line.
6557 @item ci/cubicipoldeint
6558 Cubic interpolating deinterlacing filter deinterlaces the given block by
6559 cubically interpolating every second line.
6561 @item md/mediandeint
6562 Median deinterlacing filter that deinterlaces the given block by applying a
6563 median filter to every second line.
6565 @item fd/ffmpegdeint
6566 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
6567 second line with a @code{(-1 4 2 4 -1)} filter.
6570 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
6571 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
6573 @item fq/forceQuant[|quantizer]
6574 Overrides the quantizer table from the input with the constant quantizer you
6582 Default pp filter combination (@code{hb|a,vb|a,dr|a})
6585 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
6588 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
6591 @subsection Examples
6595 Apply horizontal and vertical deblocking, deringing and automatic
6596 brightness/contrast:
6602 Apply default filters without brightness/contrast correction:
6608 Apply default filters and temporal denoiser:
6610 pp=default/tmpnoise|1|2|3
6614 Apply deblocking on luminance only, and switch vertical deblocking on or off
6615 automatically depending on available CPU time:
6623 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
6624 Ratio) between two input videos.
6626 This filter takes in input two input videos, the first input is
6627 considered the "main" source and is passed unchanged to the
6628 output. The second input is used as a "reference" video for computing
6631 Both video inputs must have the same resolution and pixel format for
6632 this filter to work correctly. Also it assumes that both inputs
6633 have the same number of frames, which are compared one by one.
6635 The obtained average PSNR is printed through the logging system.
6637 The filter stores the accumulated MSE (mean squared error) of each
6638 frame, and at the end of the processing it is averaged across all frames
6639 equally, and the following formula is applied to obtain the PSNR:
6642 PSNR = 10*log10(MAX^2/MSE)
6645 Where MAX is the average of the maximum values of each component of the
6648 The description of the accepted parameters follows.
6652 If specified the filter will use the named file to save the PSNR of
6653 each individual frame.
6656 The file printed if @var{stats_file} is selected, contains a sequence of
6657 key/value pairs of the form @var{key}:@var{value} for each compared
6660 A description of each shown parameter follows:
6664 sequential number of the input frame, starting from 1
6667 Mean Square Error pixel-by-pixel average difference of the compared
6668 frames, averaged over all the image components.
6670 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
6671 Mean Square Error pixel-by-pixel average difference of the compared
6672 frames for the component specified by the suffix.
6674 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
6675 Peak Signal to Noise ratio of the compared frames for the component
6676 specified by the suffix.
6681 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
6682 [main][ref] psnr="stats_file=stats.log" [out]
6685 On this example the input file being processed is compared with the
6686 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
6687 is stored in @file{stats.log}.
6692 Pulldown reversal (inverse telecine) filter, capable of handling mixed
6693 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
6696 The pullup filter is designed to take advantage of future context in making
6697 its decisions. This filter is stateless in the sense that it does not lock
6698 onto a pattern to follow, but it instead looks forward to the following
6699 fields in order to identify matches and rebuild progressive frames.
6701 To produce content with an even framerate, insert the fps filter after
6702 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
6703 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
6705 The filter accepts the following options:
6712 These options set the amount of "junk" to ignore at the left, right, top, and
6713 bottom of the image, respectively. Left and right are in units of 8 pixels,
6714 while top and bottom are in units of 2 lines.
6715 The default is 8 pixels on each side.
6718 Set the strict breaks. Setting this option to 1 will reduce the chances of
6719 filter generating an occasional mismatched frame, but it may also cause an
6720 excessive number of frames to be dropped during high motion sequences.
6721 Conversely, setting it to -1 will make filter match fields more easily.
6722 This may help processing of video where there is slight blurring between
6723 the fields, but may also cause there to be interlaced frames in the output.
6724 Default value is @code{0}.
6727 Set the metric plane to use. It accepts the following values:
6733 Use chroma blue plane.
6736 Use chroma red plane.
6739 This option may be set to use chroma plane instead of the default luma plane
6740 for doing filter's computations. This may improve accuracy on very clean
6741 source material, but more likely will decrease accuracy, especially if there
6742 is chroma noise (rainbow effect) or any grayscale video.
6743 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
6744 load and make pullup usable in realtime on slow machines.
6747 For best results (without duplicated frames in the output file) it is
6748 necessary to change the output frame rate. For example, to inverse
6749 telecine NTSC input:
6751 ffmpeg -i input -vf pullup -r 24000/1001 ...
6756 Suppress a TV station logo, using an image file to determine which
6757 pixels comprise the logo. It works by filling in the pixels that
6758 comprise the logo with neighboring pixels.
6760 The filter accepts the following options:
6764 Set the filter bitmap file, which can be any image format supported by
6765 libavformat. The width and height of the image file must match those of the
6766 video stream being processed.
6769 Pixels in the provided bitmap image with a value of zero are not
6770 considered part of the logo, non-zero pixels are considered part of
6771 the logo. If you use white (255) for the logo and black (0) for the
6772 rest, you will be safe. For making the filter bitmap, it is
6773 recommended to take a screen capture of a black frame with the logo
6774 visible, and then using a threshold filter followed by the erode
6775 filter once or twice.
6777 If needed, little splotches can be fixed manually. Remember that if
6778 logo pixels are not covered, the filter quality will be much
6779 reduced. Marking too many pixels as part of the logo does not hurt as
6780 much, but it will increase the amount of blurring needed to cover over
6781 the image and will destroy more information than necessary, and extra
6782 pixels will slow things down on a large logo.
6786 Rotate video by an arbitrary angle expressed in radians.
6788 The filter accepts the following options:
6790 A description of the optional parameters follows.
6793 Set an expression for the angle by which to rotate the input video
6794 clockwise, expressed as a number of radians. A negative value will
6795 result in a counter-clockwise rotation. By default it is set to "0".
6797 This expression is evaluated for each frame.
6800 Set the output width expression, default value is "iw".
6801 This expression is evaluated just once during configuration.
6804 Set the output height expression, default value is "ih".
6805 This expression is evaluated just once during configuration.
6808 Enable bilinear interpolation if set to 1, a value of 0 disables
6809 it. Default value is 1.
6812 Set the color used to fill the output area not covered by the rotated
6813 image. For the generalsyntax of this option, check the "Color" section in the
6814 ffmpeg-utils manual. If the special value "none" is selected then no
6815 background is printed (useful for example if the background is never shown).
6817 Default value is "black".
6820 The expressions for the angle and the output size can contain the
6821 following constants and functions:
6825 sequential number of the input frame, starting from 0. It is always NAN
6826 before the first frame is filtered.
6829 time in seconds of the input frame, it is set to 0 when the filter is
6830 configured. It is always NAN before the first frame is filtered.
6834 horizontal and vertical chroma subsample values. For example for the
6835 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6839 the input video width and height
6843 the output width and height, that is the size of the padded area as
6844 specified by the @var{width} and @var{height} expressions
6848 the minimal width/height required for completely containing the input
6849 video rotated by @var{a} radians.
6851 These are only available when computing the @option{out_w} and
6852 @option{out_h} expressions.
6855 @subsection Examples
6859 Rotate the input by PI/6 radians clockwise:
6865 Rotate the input by PI/6 radians counter-clockwise:
6871 Rotate the input by 45 degrees clockwise:
6877 Apply a constant rotation with period T, starting from an angle of PI/3:
6879 rotate=PI/3+2*PI*t/T
6883 Make the input video rotation oscillating with a period of T
6884 seconds and an amplitude of A radians:
6886 rotate=A*sin(2*PI/T*t)
6890 Rotate the video, output size is chosen so that the whole rotating
6891 input video is always completely contained in the output:
6893 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
6897 Rotate the video, reduce the output size so that no background is ever
6900 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
6904 @subsection Commands
6906 The filter supports the following commands:
6910 Set the angle expression.
6911 The command accepts the same syntax of the corresponding option.
6913 If the specified expression is not valid, it is kept at its current
6919 Apply Shape Adaptive Blur.
6921 The filter accepts the following options:
6924 @item luma_radius, lr
6925 Set luma blur filter strength, must be a value in range 0.1-4.0, default
6926 value is 1.0. A greater value will result in a more blurred image, and
6927 in slower processing.
6929 @item luma_pre_filter_radius, lpfr
6930 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
6933 @item luma_strength, ls
6934 Set luma maximum difference between pixels to still be considered, must
6935 be a value in the 0.1-100.0 range, default value is 1.0.
6937 @item chroma_radius, cr
6938 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
6939 greater value will result in a more blurred image, and in slower
6942 @item chroma_pre_filter_radius, cpfr
6943 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
6945 @item chroma_strength, cs
6946 Set chroma maximum difference between pixels to still be considered,
6947 must be a value in the 0.1-100.0 range.
6950 Each chroma option value, if not explicitly specified, is set to the
6951 corresponding luma option value.
6956 Scale (resize) the input video, using the libswscale library.
6958 The scale filter forces the output display aspect ratio to be the same
6959 of the input, by changing the output sample aspect ratio.
6961 If the input image format is different from the format requested by
6962 the next filter, the scale filter will convert the input to the
6966 The filter accepts the following options, or any of the options
6967 supported by the libswscale scaler.
6969 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
6970 the complete list of scaler options.
6975 Set the output video dimension expression. Default value is the input
6978 If the value is 0, the input width is used for the output.
6980 If one of the values is -1, the scale filter will use a value that
6981 maintains the aspect ratio of the input image, calculated from the
6982 other specified dimension. If both of them are -1, the input size is
6985 If one of the values is -n with n > 1, the scale filter will also use a value
6986 that maintains the aspect ratio of the input image, calculated from the other
6987 specified dimension. After that it will, however, make sure that the calculated
6988 dimension is divisible by n and adjust the value if necessary.
6990 See below for the list of accepted constants for use in the dimension
6994 Set the interlacing mode. It accepts the following values:
6998 Force interlaced aware scaling.
7001 Do not apply interlaced scaling.
7004 Select interlaced aware scaling depending on whether the source frames
7005 are flagged as interlaced or not.
7008 Default value is @samp{0}.
7011 Set libswscale scaling flags. See
7012 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7013 complete list of values. If not explicitly specified the filter applies
7017 Set the video size. For the syntax of this option, check the "Video size"
7018 section in the ffmpeg-utils manual.
7020 @item in_color_matrix
7021 @item out_color_matrix
7022 Set in/output YCbCr color space type.
7024 This allows the autodetected value to be overridden as well as allows forcing
7025 a specific value used for the output and encoder.
7027 If not specified, the color space type depends on the pixel format.
7033 Choose automatically.
7036 Format conforming to International Telecommunication Union (ITU)
7037 Recommendation BT.709.
7040 Set color space conforming to the United States Federal Communications
7041 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7044 Set color space conforming to:
7048 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7051 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7054 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7059 Set color space conforming to SMPTE ST 240:1999.
7064 Set in/output YCbCr sample range.
7066 This allows the autodetected value to be overridden as well as allows forcing
7067 a specific value used for the output and encoder. If not specified, the
7068 range depends on the pixel format. Possible values:
7072 Choose automatically.
7075 Set full range (0-255 in case of 8-bit luma).
7078 Set "MPEG" range (16-235 in case of 8-bit luma).
7081 @item force_original_aspect_ratio
7082 Enable decreasing or increasing output video width or height if necessary to
7083 keep the original aspect ratio. Possible values:
7087 Scale the video as specified and disable this feature.
7090 The output video dimensions will automatically be decreased if needed.
7093 The output video dimensions will automatically be increased if needed.
7097 One useful instance of this option is that when you know a specific device's
7098 maximum allowed resolution, you can use this to limit the output video to
7099 that, while retaining the aspect ratio. For example, device A allows
7100 1280x720 playback, and your video is 1920x800. Using this option (set it to
7101 decrease) and specifying 1280x720 to the command line makes the output
7104 Please note that this is a different thing than specifying -1 for @option{w}
7105 or @option{h}, you still need to specify the output resolution for this option
7110 The values of the @option{w} and @option{h} options are expressions
7111 containing the following constants:
7116 The input width and height
7120 These are the same as @var{in_w} and @var{in_h}.
7124 The output (scaled) width and height
7128 These are the same as @var{out_w} and @var{out_h}
7131 The same as @var{iw} / @var{ih}
7134 input sample aspect ratio
7137 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7141 horizontal and vertical input chroma subsample values. For example for the
7142 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7146 horizontal and vertical output chroma subsample values. For example for the
7147 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7150 @subsection Examples
7154 Scale the input video to a size of 200x100
7159 This is equivalent to:
7170 Specify a size abbreviation for the output size:
7175 which can also be written as:
7181 Scale the input to 2x:
7187 The above is the same as:
7193 Scale the input to 2x with forced interlaced scaling:
7195 scale=2*iw:2*ih:interl=1
7199 Scale the input to half size:
7205 Increase the width, and set the height to the same size:
7218 Increase the height, and set the width to 3/2 of the height:
7220 scale=w=3/2*oh:h=3/5*ih
7224 Increase the size, making the size a multiple of the chroma
7227 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7231 Increase the width to a maximum of 500 pixels,
7232 keeping the same aspect ratio as the input:
7234 scale=w='min(500\, iw*3/2):h=-1'
7238 @section separatefields
7240 The @code{separatefields} takes a frame-based video input and splits
7241 each frame into its components fields, producing a new half height clip
7242 with twice the frame rate and twice the frame count.
7244 This filter use field-dominance information in frame to decide which
7245 of each pair of fields to place first in the output.
7246 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7248 @section setdar, setsar
7250 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7253 This is done by changing the specified Sample (aka Pixel) Aspect
7254 Ratio, according to the following equation:
7256 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7259 Keep in mind that the @code{setdar} filter does not modify the pixel
7260 dimensions of the video frame. Also, the display aspect ratio set by
7261 this filter may be changed by later filters in the filterchain,
7262 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7265 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7266 the filter output video.
7268 Note that as a consequence of the application of this filter, the
7269 output display aspect ratio will change according to the equation
7272 Keep in mind that the sample aspect ratio set by the @code{setsar}
7273 filter may be changed by later filters in the filterchain, e.g. if
7274 another "setsar" or a "setdar" filter is applied.
7276 It accepts the following parameters:
7279 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7280 Set the aspect ratio used by the filter.
7282 The parameter can be a floating point number string, an expression, or
7283 a string of the form @var{num}:@var{den}, where @var{num} and
7284 @var{den} are the numerator and denominator of the aspect ratio. If
7285 the parameter is not specified, it is assumed the value "0".
7286 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7290 Set the maximum integer value to use for expressing numerator and
7291 denominator when reducing the expressed aspect ratio to a rational.
7292 Default value is @code{100}.
7296 The parameter @var{sar} is an expression containing
7297 the following constants:
7301 These are approximated values for the mathematical constants e
7302 (Euler's number), pi (Greek pi), and phi (the golden ratio).
7305 The input width and height.
7308 These are the same as @var{w} / @var{h}.
7311 The input sample aspect ratio.
7314 The input display aspect ratio. It is the same as
7315 (@var{w} / @var{h}) * @var{sar}.
7318 Horizontal and vertical chroma subsample values. For example, for the
7319 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7322 @subsection Examples
7327 To change the display aspect ratio to 16:9, specify one of the following:
7335 To change the sample aspect ratio to 10:11, specify:
7341 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7342 1000 in the aspect ratio reduction, use the command:
7344 setdar=ratio=16/9:max=1000
7352 Force field for the output video frame.
7354 The @code{setfield} filter marks the interlace type field for the
7355 output frames. It does not change the input frame, but only sets the
7356 corresponding property, which affects how the frame is treated by
7357 following filters (e.g. @code{fieldorder} or @code{yadif}).
7359 The filter accepts the following options:
7364 Available values are:
7368 Keep the same field property.
7371 Mark the frame as bottom-field-first.
7374 Mark the frame as top-field-first.
7377 Mark the frame as progressive.
7383 Show a line containing various information for each input video frame.
7384 The input video is not modified.
7386 The shown line contains a sequence of key/value pairs of the form
7387 @var{key}:@var{value}.
7389 It accepts the following parameters:
7393 The (sequential) number of the input frame, starting from 0.
7396 The Presentation TimeStamp of the input frame, expressed as a number of
7397 time base units. The time base unit depends on the filter input pad.
7400 The Presentation TimeStamp of the input frame, expressed as a number of
7404 The position of the frame in the input stream, or -1 if this information is
7405 unavailable and/or meaningless (for example in case of synthetic video).
7408 The pixel format name.
7411 The sample aspect ratio of the input frame, expressed in the form
7412 @var{num}/@var{den}.
7415 The size of the input frame. For the syntax of this option, check the "Video size"
7416 section in the ffmpeg-utils manual.
7419 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
7420 for bottom field first).
7423 This is 1 if the frame is a key frame, 0 otherwise.
7426 The picture type of the input frame ("I" for an I-frame, "P" for a
7427 P-frame, "B" for a B-frame, or "?" for an unknown type).
7428 Also refer to the documentation of the @code{AVPictureType} enum and of
7429 the @code{av_get_picture_type_char} function defined in
7430 @file{libavutil/avutil.h}.
7433 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
7435 @item plane_checksum
7436 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
7437 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
7440 @section shuffleplanes
7442 Reorder and/or duplicate video planes.
7444 It accepts the following parameters:
7449 The index of the input plane to be used as the first output plane.
7452 The index of the input plane to be used as the second output plane.
7455 The index of the input plane to be used as the third output plane.
7458 The index of the input plane to be used as the fourth output plane.
7462 The first plane has the index 0. The default is to keep the input unchanged.
7464 Swap the second and third planes of the input:
7466 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
7472 Blur the input video without impacting the outlines.
7474 It accepts the following options:
7477 @item luma_radius, lr
7478 Set the luma radius. The option value must be a float number in
7479 the range [0.1,5.0] that specifies the variance of the gaussian filter
7480 used to blur the image (slower if larger). Default value is 1.0.
7482 @item luma_strength, ls
7483 Set the luma strength. The option value must be a float number
7484 in the range [-1.0,1.0] that configures the blurring. A value included
7485 in [0.0,1.0] will blur the image whereas a value included in
7486 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7488 @item luma_threshold, lt
7489 Set the luma threshold used as a coefficient to determine
7490 whether a pixel should be blurred or not. The option value must be an
7491 integer in the range [-30,30]. A value of 0 will filter all the image,
7492 a value included in [0,30] will filter flat areas and a value included
7493 in [-30,0] will filter edges. Default value is 0.
7495 @item chroma_radius, cr
7496 Set the chroma radius. The option value must be a float number in
7497 the range [0.1,5.0] that specifies the variance of the gaussian filter
7498 used to blur the image (slower if larger). Default value is 1.0.
7500 @item chroma_strength, cs
7501 Set the chroma strength. The option value must be a float number
7502 in the range [-1.0,1.0] that configures the blurring. A value included
7503 in [0.0,1.0] will blur the image whereas a value included in
7504 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7506 @item chroma_threshold, ct
7507 Set the chroma threshold used as a coefficient to determine
7508 whether a pixel should be blurred or not. The option value must be an
7509 integer in the range [-30,30]. A value of 0 will filter all the image,
7510 a value included in [0,30] will filter flat areas and a value included
7511 in [-30,0] will filter edges. Default value is 0.
7514 If a chroma option is not explicitly set, the corresponding luma value
7519 Convert between different stereoscopic image formats.
7521 The filters accept the following options:
7525 Set stereoscopic image format of input.
7527 Available values for input image formats are:
7530 side by side parallel (left eye left, right eye right)
7533 side by side crosseye (right eye left, left eye right)
7536 side by side parallel with half width resolution
7537 (left eye left, right eye right)
7540 side by side crosseye with half width resolution
7541 (right eye left, left eye right)
7544 above-below (left eye above, right eye below)
7547 above-below (right eye above, left eye below)
7550 above-below with half height resolution
7551 (left eye above, right eye below)
7554 above-below with half height resolution
7555 (right eye above, left eye below)
7558 alternating frames (left eye first, right eye second)
7561 alternating frames (right eye first, left eye second)
7563 Default value is @samp{sbsl}.
7567 Set stereoscopic image format of output.
7569 Available values for output image formats are all the input formats as well as:
7572 anaglyph red/blue gray
7573 (red filter on left eye, blue filter on right eye)
7576 anaglyph red/green gray
7577 (red filter on left eye, green filter on right eye)
7580 anaglyph red/cyan gray
7581 (red filter on left eye, cyan filter on right eye)
7584 anaglyph red/cyan half colored
7585 (red filter on left eye, cyan filter on right eye)
7588 anaglyph red/cyan color
7589 (red filter on left eye, cyan filter on right eye)
7592 anaglyph red/cyan color optimized with the least squares projection of dubois
7593 (red filter on left eye, cyan filter on right eye)
7596 anaglyph green/magenta gray
7597 (green filter on left eye, magenta filter on right eye)
7600 anaglyph green/magenta half colored
7601 (green filter on left eye, magenta filter on right eye)
7604 anaglyph green/magenta colored
7605 (green filter on left eye, magenta filter on right eye)
7608 anaglyph green/magenta color optimized with the least squares projection of dubois
7609 (green filter on left eye, magenta filter on right eye)
7612 anaglyph yellow/blue gray
7613 (yellow filter on left eye, blue filter on right eye)
7616 anaglyph yellow/blue half colored
7617 (yellow filter on left eye, blue filter on right eye)
7620 anaglyph yellow/blue colored
7621 (yellow filter on left eye, blue filter on right eye)
7624 anaglyph yellow/blue color optimized with the least squares projection of dubois
7625 (yellow filter on left eye, blue filter on right eye)
7628 interleaved rows (left eye has top row, right eye starts on next row)
7631 interleaved rows (right eye has top row, left eye starts on next row)
7634 mono output (left eye only)
7637 mono output (right eye only)
7640 Default value is @samp{arcd}.
7643 @subsection Examples
7647 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
7653 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
7661 Apply a simple postprocessing filter that compresses and decompresses the image
7662 at several (or - in the case of @option{quality} level @code{6} - all) shifts
7663 and average the results.
7665 The filter accepts the following options:
7669 Set quality. This option defines the number of levels for averaging. It accepts
7670 an integer in the range 0-6. If set to @code{0}, the filter will have no
7671 effect. A value of @code{6} means the higher quality. For each increment of
7672 that value the speed drops by a factor of approximately 2. Default value is
7676 Force a constant quantization parameter. If not set, the filter will use the QP
7677 from the video stream (if available).
7680 Set thresholding mode. Available modes are:
7684 Set hard thresholding (default).
7686 Set soft thresholding (better de-ringing effect, but likely blurrier).
7690 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
7691 option may cause flicker since the B-Frames have often larger QP. Default is
7692 @code{0} (not enabled).
7698 Draw subtitles on top of input video using the libass library.
7700 To enable compilation of this filter you need to configure FFmpeg with
7701 @code{--enable-libass}. This filter also requires a build with libavcodec and
7702 libavformat to convert the passed subtitles file to ASS (Advanced Substation
7703 Alpha) subtitles format.
7705 The filter accepts the following options:
7709 Set the filename of the subtitle file to read. It must be specified.
7712 Specify the size of the original video, the video for which the ASS file
7713 was composed. For the syntax of this option, check the "Video size" section in
7714 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
7715 this is necessary to correctly scale the fonts if the aspect ratio has been
7719 Set subtitles input character encoding. @code{subtitles} filter only. Only
7720 useful if not UTF-8.
7723 If the first key is not specified, it is assumed that the first value
7724 specifies the @option{filename}.
7726 For example, to render the file @file{sub.srt} on top of the input
7727 video, use the command:
7732 which is equivalent to:
7734 subtitles=filename=sub.srt
7739 Scale the input by 2x and smooth using the Super2xSaI (Scale and
7740 Interpolate) pixel art scaling algorithm.
7742 Useful for enlarging pixel art images without reducing sharpness.
7749 Apply telecine process to the video.
7751 This filter accepts the following options:
7760 The default value is @code{top}.
7764 A string of numbers representing the pulldown pattern you wish to apply.
7765 The default value is @code{23}.
7769 Some typical patterns:
7774 24p: 2332 (preferred)
7781 24p: 222222222223 ("Euro pulldown")
7787 Select the most representative frame in a given sequence of consecutive frames.
7789 The filter accepts the following options:
7793 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
7794 will pick one of them, and then handle the next batch of @var{n} frames until
7795 the end. Default is @code{100}.
7798 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
7799 value will result in a higher memory usage, so a high value is not recommended.
7801 @subsection Examples
7805 Extract one picture each 50 frames:
7811 Complete example of a thumbnail creation with @command{ffmpeg}:
7813 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
7819 Tile several successive frames together.
7821 The filter accepts the following options:
7826 Set the grid size (i.e. the number of lines and columns). For the syntax of
7827 this option, check the "Video size" section in the ffmpeg-utils manual.
7830 Set the maximum number of frames to render in the given area. It must be less
7831 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
7832 the area will be used.
7835 Set the outer border margin in pixels.
7838 Set the inner border thickness (i.e. the number of pixels between frames). For
7839 more advanced padding options (such as having different values for the edges),
7840 refer to the pad video filter.
7843 Specify the color of the unused areaFor the syntax of this option, check the
7844 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
7848 @subsection Examples
7852 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
7854 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
7856 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
7857 duplicating each output frame to accommodate the originally detected frame
7861 Display @code{5} pictures in an area of @code{3x2} frames,
7862 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
7863 mixed flat and named options:
7865 tile=3x2:nb_frames=5:padding=7:margin=2
7871 Perform various types of temporal field interlacing.
7873 Frames are counted starting from 1, so the first input frame is
7876 The filter accepts the following options:
7881 Specify the mode of the interlacing. This option can also be specified
7882 as a value alone. See below for a list of values for this option.
7884 Available values are:
7888 Move odd frames into the upper field, even into the lower field,
7889 generating a double height frame at half frame rate.
7892 Only output even frames, odd frames are dropped, generating a frame with
7893 unchanged height at half frame rate.
7896 Only output odd frames, even frames are dropped, generating a frame with
7897 unchanged height at half frame rate.
7900 Expand each frame to full height, but pad alternate lines with black,
7901 generating a frame with double height at the same input frame rate.
7903 @item interleave_top, 4
7904 Interleave the upper field from odd frames with the lower field from
7905 even frames, generating a frame with unchanged height at half frame rate.
7907 @item interleave_bottom, 5
7908 Interleave the lower field from odd frames with the upper field from
7909 even frames, generating a frame with unchanged height at half frame rate.
7911 @item interlacex2, 6
7912 Double frame rate with unchanged height. Frames are inserted each
7913 containing the second temporal field from the previous input frame and
7914 the first temporal field from the next input frame. This mode relies on
7915 the top_field_first flag. Useful for interlaced video displays with no
7916 field synchronisation.
7919 Numeric values are deprecated but are accepted for backward
7920 compatibility reasons.
7922 Default mode is @code{merge}.
7925 Specify flags influencing the filter process.
7927 Available value for @var{flags} is:
7930 @item low_pass_filter, vlfp
7931 Enable vertical low-pass filtering in the filter.
7932 Vertical low-pass filtering is required when creating an interlaced
7933 destination from a progressive source which contains high-frequency
7934 vertical detail. Filtering will reduce interlace 'twitter' and Moire
7937 Vertical low-pass filtering can only be enabled for @option{mode}
7938 @var{interleave_top} and @var{interleave_bottom}.
7945 Transpose rows with columns in the input video and optionally flip it.
7947 It accepts the following parameters:
7952 Specify the transposition direction.
7954 Can assume the following values:
7956 @item 0, 4, cclock_flip
7957 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
7965 Rotate by 90 degrees clockwise, that is:
7973 Rotate by 90 degrees counterclockwise, that is:
7980 @item 3, 7, clock_flip
7981 Rotate by 90 degrees clockwise and vertically flip, that is:
7989 For values between 4-7, the transposition is only done if the input
7990 video geometry is portrait and not landscape. These values are
7991 deprecated, the @code{passthrough} option should be used instead.
7993 Numerical values are deprecated, and should be dropped in favor of
7997 Do not apply the transposition if the input geometry matches the one
7998 specified by the specified value. It accepts the following values:
8001 Always apply transposition.
8003 Preserve portrait geometry (when @var{height} >= @var{width}).
8005 Preserve landscape geometry (when @var{width} >= @var{height}).
8008 Default value is @code{none}.
8011 For example to rotate by 90 degrees clockwise and preserve portrait
8014 transpose=dir=1:passthrough=portrait
8017 The command above can also be specified as:
8019 transpose=1:portrait
8023 Trim the input so that the output contains one continuous subpart of the input.
8025 It accepts the following parameters:
8028 Specify the time of the start of the kept section, i.e. the frame with the
8029 timestamp @var{start} will be the first frame in the output.
8032 Specify the time of the first frame that will be dropped, i.e. the frame
8033 immediately preceding the one with the timestamp @var{end} will be the last
8034 frame in the output.
8037 This is the same as @var{start}, except this option sets the start timestamp
8038 in timebase units instead of seconds.
8041 This is the same as @var{end}, except this option sets the end timestamp
8042 in timebase units instead of seconds.
8045 The maximum duration of the output in seconds.
8048 The number of the first frame that should be passed to the output.
8051 The number of the first frame that should be dropped.
8054 @option{start}, @option{end}, @option{duration} are expressed as time
8055 duration specifications, check the "Time duration" section in the
8056 ffmpeg-utils manual.
8058 Note that the first two sets of the start/end options and the @option{duration}
8059 option look at the frame timestamp, while the _frame variants simply count the
8060 frames that pass through the filter. Also note that this filter does not modify
8061 the timestamps. If you wish for the output timestamps to start at zero, insert a
8062 setpts filter after the trim filter.
8064 If multiple start or end options are set, this filter tries to be greedy and
8065 keep all the frames that match at least one of the specified constraints. To keep
8066 only the part that matches all the constraints at once, chain multiple trim
8069 The defaults are such that all the input is kept. So it is possible to set e.g.
8070 just the end values to keep everything before the specified time.
8075 Drop everything except the second minute of input:
8077 ffmpeg -i INPUT -vf trim=60:120
8081 Keep only the first second:
8083 ffmpeg -i INPUT -vf trim=duration=1
8091 Sharpen or blur the input video.
8093 It accepts the following parameters:
8096 @item luma_msize_x, lx
8097 Set the luma matrix horizontal size. It must be an odd integer between
8098 3 and 63. The default value is 5.
8100 @item luma_msize_y, ly
8101 Set the luma matrix vertical size. It must be an odd integer between 3
8102 and 63. The default value is 5.
8104 @item luma_amount, la
8105 Set the luma effect strength. It must be a floating point number, reasonable
8106 values lay between -1.5 and 1.5.
8108 Negative values will blur the input video, while positive values will
8109 sharpen it, a value of zero will disable the effect.
8111 Default value is 1.0.
8113 @item chroma_msize_x, cx
8114 Set the chroma matrix horizontal size. It must be an odd integer
8115 between 3 and 63. The default value is 5.
8117 @item chroma_msize_y, cy
8118 Set the chroma matrix vertical size. It must be an odd integer
8119 between 3 and 63. The default value is 5.
8121 @item chroma_amount, ca
8122 Set the chroma effect strength. It must be a floating point number, reasonable
8123 values lay between -1.5 and 1.5.
8125 Negative values will blur the input video, while positive values will
8126 sharpen it, a value of zero will disable the effect.
8128 Default value is 0.0.
8131 If set to 1, specify using OpenCL capabilities, only available if
8132 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
8136 All parameters are optional and default to the equivalent of the
8137 string '5:5:1.0:5:5:0.0'.
8139 @subsection Examples
8143 Apply strong luma sharpen effect:
8145 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
8149 Apply a strong blur of both luma and chroma parameters:
8151 unsharp=7:7:-2:7:7:-2
8155 @anchor{vidstabdetect}
8156 @section vidstabdetect
8158 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
8159 @ref{vidstabtransform} for pass 2.
8161 This filter generates a file with relative translation and rotation
8162 transform information about subsequent frames, which is then used by
8163 the @ref{vidstabtransform} filter.
8165 To enable compilation of this filter you need to configure FFmpeg with
8166 @code{--enable-libvidstab}.
8168 This filter accepts the following options:
8172 Set the path to the file used to write the transforms information.
8173 Default value is @file{transforms.trf}.
8176 Set how shaky the video is and how quick the camera is. It accepts an
8177 integer in the range 1-10, a value of 1 means little shakiness, a
8178 value of 10 means strong shakiness. Default value is 5.
8181 Set the accuracy of the detection process. It must be a value in the
8182 range 1-15. A value of 1 means low accuracy, a value of 15 means high
8183 accuracy. Default value is 15.
8186 Set stepsize of the search process. The region around minimum is
8187 scanned with 1 pixel resolution. Default value is 6.
8190 Set minimum contrast. Below this value a local measurement field is
8191 discarded. Must be a floating point value in the range 0-1. Default
8195 Set reference frame number for tripod mode.
8197 If enabled, the motion of the frames is compared to a reference frame
8198 in the filtered stream, identified by the specified number. The idea
8199 is to compensate all movements in a more-or-less static scene and keep
8200 the camera view absolutely still.
8202 If set to 0, it is disabled. The frames are counted starting from 1.
8205 Show fields and transforms in the resulting frames. It accepts an
8206 integer in the range 0-2. Default value is 0, which disables any
8210 @subsection Examples
8220 Analyze strongly shaky movie and put the results in file
8221 @file{mytransforms.trf}:
8223 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
8227 Visualize the result of internal transformations in the resulting
8230 vidstabdetect=show=1
8234 Analyze a video with medium shakiness using @command{ffmpeg}:
8236 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
8240 @anchor{vidstabtransform}
8241 @section vidstabtransform
8243 Video stabilization/deshaking: pass 2 of 2,
8244 see @ref{vidstabdetect} for pass 1.
8246 Read a file with transform information for each frame and
8247 apply/compensate them. Together with the @ref{vidstabdetect}
8248 filter this can be used to deshake videos. See also
8249 @url{http://public.hronopik.de/vid.stab}. It is important to also use
8250 the unsharp filter, see below.
8252 To enable compilation of this filter you need to configure FFmpeg with
8253 @code{--enable-libvidstab}.
8259 Set path to the file used to read the transforms. Default value is
8260 @file{transforms.trf}).
8263 Set the number of frames (value*2 + 1) used for lowpass filtering the
8264 camera movements. Default value is 10.
8266 For example a number of 10 means that 21 frames are used (10 in the
8267 past and 10 in the future) to smoothen the motion in the video. A
8268 larger values leads to a smoother video, but limits the acceleration
8269 of the camera (pan/tilt movements). 0 is a special case where a
8270 static camera is simulated.
8273 Set the camera path optimization algorithm.
8275 Accepted values are:
8278 gaussian kernel low-pass filter on camera motion (default)
8280 averaging on transformations
8284 Set maximal number of pixels to translate frames. Default value is -1,
8288 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
8289 value is -1, meaning no limit.
8292 Specify how to deal with borders that may be visible due to movement
8295 Available values are:
8298 keep image information from previous frame (default)
8300 fill the border black
8304 Invert transforms if set to 1. Default value is 0.
8307 Consider transforms as relative to previsou frame if set to 1,
8308 absolute if set to 0. Default value is 0.
8311 Set percentage to zoom. A positive value will result in a zoom-in
8312 effect, a negative value in a zoom-out effect. Default value is 0 (no
8316 Set optimal zooming to avoid borders.
8318 Accepted values are:
8323 optimal static zoom value is determined (only very strong movements
8324 will lead to visible borders) (default)
8326 optimal adaptive zoom value is determined (no borders will be
8327 visible), see @option{zoomspeed}
8330 Note that the value given at zoom is added to the one calculated here.
8333 Set percent to zoom maximally each frame (enabled when
8334 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
8338 Specify type of interpolation.
8340 Available values are:
8345 linear only horizontal
8347 linear in both directions (default)
8349 cubic in both directions (slow)
8353 Enable virtual tripod mode if set to 1, which is equivalent to
8354 @code{relative=0:smoothing=0}. Default value is 0.
8356 Use also @code{tripod} option of @ref{vidstabdetect}.
8359 Increase log verbosity if set to 1. Also the detected global motions
8360 are written to the temporary file @file{global_motions.trf}. Default
8364 @subsection Examples
8368 Use @command{ffmpeg} for a typical stabilization with default values:
8370 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
8373 Note the use of the unsharp filter which is always recommended.
8376 Zoom in a bit more and load transform data from a given file:
8378 vidstabtransform=zoom=5:input="mytransforms.trf"
8382 Smoothen the video even more:
8384 vidstabtransform=smoothing=30
8390 Flip the input video vertically.
8392 For example, to vertically flip a video with @command{ffmpeg}:
8394 ffmpeg -i in.avi -vf "vflip" out.avi
8399 Make or reverse a natural vignetting effect.
8401 The filter accepts the following options:
8405 Set lens angle expression as a number of radians.
8407 The value is clipped in the @code{[0,PI/2]} range.
8409 Default value: @code{"PI/5"}
8413 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
8417 Set forward/backward mode.
8419 Available modes are:
8422 The larger the distance from the central point, the darker the image becomes.
8425 The larger the distance from the central point, the brighter the image becomes.
8426 This can be used to reverse a vignette effect, though there is no automatic
8427 detection to extract the lens @option{angle} and other settings (yet). It can
8428 also be used to create a burning effect.
8431 Default value is @samp{forward}.
8434 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
8436 It accepts the following values:
8439 Evaluate expressions only once during the filter initialization.
8442 Evaluate expressions for each incoming frame. This is way slower than the
8443 @samp{init} mode since it requires all the scalers to be re-computed, but it
8444 allows advanced dynamic expressions.
8447 Default value is @samp{init}.
8450 Set dithering to reduce the circular banding effects. Default is @code{1}
8454 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
8455 Setting this value to the SAR of the input will make a rectangular vignetting
8456 following the dimensions of the video.
8458 Default is @code{1/1}.
8461 @subsection Expressions
8463 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
8464 following parameters.
8469 input width and height
8472 the number of input frame, starting from 0
8475 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
8476 @var{TB} units, NAN if undefined
8479 frame rate of the input video, NAN if the input frame rate is unknown
8482 the PTS (Presentation TimeStamp) of the filtered video frame,
8483 expressed in seconds, NAN if undefined
8486 time base of the input video
8490 @subsection Examples
8494 Apply simple strong vignetting effect:
8500 Make a flickering vignetting:
8502 vignette='PI/4+random(1)*PI/50':eval=frame
8509 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
8510 Deinterlacing Filter").
8512 Based on the process described by Martin Weston for BBC R&D, and
8513 implemented based on the de-interlace algorithm written by Jim
8514 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
8515 uses filter coefficients calculated by BBC R&D.
8517 There are two sets of filter coefficients, so called "simple":
8518 and "complex". Which set of filter coefficients is used can
8519 be set by passing an optional parameter:
8523 Set the interlacing filter coefficients. Accepts one of the following values:
8527 Simple filter coefficient set.
8529 More-complex filter coefficient set.
8531 Default value is @samp{complex}.
8534 Specify which frames to deinterlace. Accept one of the following values:
8538 Deinterlace all frames,
8540 Only deinterlace frames marked as interlaced.
8543 Default value is @samp{all}.
8549 Deinterlace the input video ("yadif" means "yet another deinterlacing
8552 It accepts the following parameters:
8558 The interlacing mode to adopt. It accepts one of the following values:
8562 Output one frame for each frame.
8564 Output one frame for each field.
8565 @item 2, send_frame_nospatial
8566 Like @code{send_frame}, but it skips the spatial interlacing check.
8567 @item 3, send_field_nospatial
8568 Like @code{send_field}, but it skips the spatial interlacing check.
8571 The default value is @code{send_frame}.
8574 The picture field parity assumed for the input interlaced video. It accepts one
8575 of the following values:
8579 Assume the top field is first.
8581 Assume the bottom field is first.
8583 Enable automatic detection of field parity.
8586 The default value is @code{auto}.
8587 If the interlacing is unknown or the decoder does not export this information,
8588 top field first will be assumed.
8591 Specify which frames to deinterlace. Accept one of the following
8596 Deinterlace all frames.
8598 Only deinterlace frames marked as interlaced.
8601 The default value is @code{all}.
8604 @c man end VIDEO FILTERS
8606 @chapter Video Sources
8607 @c man begin VIDEO SOURCES
8609 Below is a description of the currently available video sources.
8613 Buffer video frames, and make them available to the filter chain.
8615 This source is mainly intended for a programmatic use, in particular
8616 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
8618 It accepts the following parameters:
8623 Specify the size (width and height) of the buffered video frames. For the
8624 syntax of this option, check the "Video size" section in the ffmpeg-utils
8628 The input video width.
8631 The input video height.
8634 A string representing the pixel format of the buffered video frames.
8635 It may be a number corresponding to a pixel format, or a pixel format
8639 Specify the timebase assumed by the timestamps of the buffered frames.
8642 Specify the frame rate expected for the video stream.
8644 @item pixel_aspect, sar
8645 The sample (pixel) aspect ratio of the input video.
8648 Specify the optional parameters to be used for the scale filter which
8649 is automatically inserted when an input change is detected in the
8650 input size or format.
8655 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
8658 will instruct the source to accept video frames with size 320x240 and
8659 with format "yuv410p", assuming 1/24 as the timestamps timebase and
8660 square pixels (1:1 sample aspect ratio).
8661 Since the pixel format with name "yuv410p" corresponds to the number 6
8662 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
8663 this example corresponds to:
8665 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
8668 Alternatively, the options can be specified as a flat string, but this
8669 syntax is deprecated:
8671 @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}]
8675 Create a pattern generated by an elementary cellular automaton.
8677 The initial state of the cellular automaton can be defined through the
8678 @option{filename}, and @option{pattern} options. If such options are
8679 not specified an initial state is created randomly.
8681 At each new frame a new row in the video is filled with the result of
8682 the cellular automaton next generation. The behavior when the whole
8683 frame is filled is defined by the @option{scroll} option.
8685 This source accepts the following options:
8689 Read the initial cellular automaton state, i.e. the starting row, from
8691 In the file, each non-whitespace character is considered an alive
8692 cell, a newline will terminate the row, and further characters in the
8693 file will be ignored.
8696 Read the initial cellular automaton state, i.e. the starting row, from
8697 the specified string.
8699 Each non-whitespace character in the string is considered an alive
8700 cell, a newline will terminate the row, and further characters in the
8701 string will be ignored.
8704 Set the video rate, that is the number of frames generated per second.
8707 @item random_fill_ratio, ratio
8708 Set the random fill ratio for the initial cellular automaton row. It
8709 is a floating point number value ranging from 0 to 1, defaults to
8712 This option is ignored when a file or a pattern is specified.
8714 @item random_seed, seed
8715 Set the seed for filling randomly the initial row, must be an integer
8716 included between 0 and UINT32_MAX. If not specified, or if explicitly
8717 set to -1, the filter will try to use a good random seed on a best
8721 Set the cellular automaton rule, it is a number ranging from 0 to 255.
8722 Default value is 110.
8725 Set the size of the output video. For the syntax of this option, check
8726 the "Video size" section in the ffmpeg-utils manual.
8728 If @option{filename} or @option{pattern} is specified, the size is set
8729 by default to the width of the specified initial state row, and the
8730 height is set to @var{width} * PHI.
8732 If @option{size} is set, it must contain the width of the specified
8733 pattern string, and the specified pattern will be centered in the
8736 If a filename or a pattern string is not specified, the size value
8737 defaults to "320x518" (used for a randomly generated initial state).
8740 If set to 1, scroll the output upward when all the rows in the output
8741 have been already filled. If set to 0, the new generated row will be
8742 written over the top row just after the bottom row is filled.
8745 @item start_full, full
8746 If set to 1, completely fill the output with generated rows before
8747 outputting the first frame.
8748 This is the default behavior, for disabling set the value to 0.
8751 If set to 1, stitch the left and right row edges together.
8752 This is the default behavior, for disabling set the value to 0.
8755 @subsection Examples
8759 Read the initial state from @file{pattern}, and specify an output of
8762 cellauto=f=pattern:s=200x400
8766 Generate a random initial row with a width of 200 cells, with a fill
8769 cellauto=ratio=2/3:s=200x200
8773 Create a pattern generated by rule 18 starting by a single alive cell
8774 centered on an initial row with width 100:
8776 cellauto=p=@@:s=100x400:full=0:rule=18
8780 Specify a more elaborated initial pattern:
8782 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
8789 Generate a Mandelbrot set fractal, and progressively zoom towards the
8790 point specified with @var{start_x} and @var{start_y}.
8792 This source accepts the following options:
8797 Set the terminal pts value. Default value is 400.
8800 Set the terminal scale value.
8801 Must be a floating point value. Default value is 0.3.
8804 Set the inner coloring mode, that is the algorithm used to draw the
8805 Mandelbrot fractal internal region.
8807 It shall assume one of the following values:
8812 Show time until convergence.
8814 Set color based on point closest to the origin of the iterations.
8819 Default value is @var{mincol}.
8822 Set the bailout value. Default value is 10.0.
8825 Set the maximum of iterations performed by the rendering
8826 algorithm. Default value is 7189.
8829 Set outer coloring mode.
8830 It shall assume one of following values:
8832 @item iteration_count
8833 Set iteration cound mode.
8834 @item normalized_iteration_count
8835 set normalized iteration count mode.
8837 Default value is @var{normalized_iteration_count}.
8840 Set frame rate, expressed as number of frames per second. Default
8844 Set frame size. For the syntax of this option, check the "Video
8845 size" section in the ffmpeg-utils manual. Default value is "640x480".
8848 Set the initial scale value. Default value is 3.0.
8851 Set the initial x position. Must be a floating point value between
8852 -100 and 100. Default value is -0.743643887037158704752191506114774.
8855 Set the initial y position. Must be a floating point value between
8856 -100 and 100. Default value is -0.131825904205311970493132056385139.
8861 Generate various test patterns, as generated by the MPlayer test filter.
8863 The size of the generated video is fixed, and is 256x256.
8864 This source is useful in particular for testing encoding features.
8866 This source accepts the following options:
8871 Specify the frame rate of the sourced video, as the number of frames
8872 generated per second. It has to be a string in the format
8873 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
8874 number or a valid video frame rate abbreviation. The default value is
8878 Set the video duration of the sourced video. The accepted syntax is:
8883 See also the function @code{av_parse_time()}.
8885 If not specified, or the expressed duration is negative, the video is
8886 supposed to be generated forever.
8890 Set the number or the name of the test to perform. Supported tests are:
8906 Default value is "all", which will cycle through the list of all tests.
8914 will generate a "dc_luma" test pattern.
8918 Provide a frei0r source.
8920 To enable compilation of this filter you need to install the frei0r
8921 header and configure FFmpeg with @code{--enable-frei0r}.
8923 This source accepts the following parameters:
8928 The size of the video to generate. For the syntax of this option, check the
8929 "Video size" section in the ffmpeg-utils manual.
8932 The framerate of the generated video. It may be a string of the form
8933 @var{num}/@var{den} or a frame rate abbreviation.
8936 The name to the frei0r source to load. For more information regarding frei0r and
8937 how to set the parameters, read the @ref{frei0r} section in the video filters
8941 A '|'-separated list of parameters to pass to the frei0r source.
8945 For example, to generate a frei0r partik0l source with size 200x200
8946 and frame rate 10 which is overlayed on the overlay filter main input:
8948 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
8953 Generate a life pattern.
8955 This source is based on a generalization of John Conway's life game.
8957 The sourced input represents a life grid, each pixel represents a cell
8958 which can be in one of two possible states, alive or dead. Every cell
8959 interacts with its eight neighbours, which are the cells that are
8960 horizontally, vertically, or diagonally adjacent.
8962 At each interaction the grid evolves according to the adopted rule,
8963 which specifies the number of neighbor alive cells which will make a
8964 cell stay alive or born. The @option{rule} option allows one to specify
8967 This source accepts the following options:
8971 Set the file from which to read the initial grid state. In the file,
8972 each non-whitespace character is considered an alive cell, and newline
8973 is used to delimit the end of each row.
8975 If this option is not specified, the initial grid is generated
8979 Set the video rate, that is the number of frames generated per second.
8982 @item random_fill_ratio, ratio
8983 Set the random fill ratio for the initial random grid. It is a
8984 floating point number value ranging from 0 to 1, defaults to 1/PHI.
8985 It is ignored when a file is specified.
8987 @item random_seed, seed
8988 Set the seed for filling the initial random grid, must be an integer
8989 included between 0 and UINT32_MAX. If not specified, or if explicitly
8990 set to -1, the filter will try to use a good random seed on a best
8996 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
8997 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
8998 @var{NS} specifies the number of alive neighbor cells which make a
8999 live cell stay alive, and @var{NB} the number of alive neighbor cells
9000 which make a dead cell to become alive (i.e. to "born").
9001 "s" and "b" can be used in place of "S" and "B", respectively.
9003 Alternatively a rule can be specified by an 18-bits integer. The 9
9004 high order bits are used to encode the next cell state if it is alive
9005 for each number of neighbor alive cells, the low order bits specify
9006 the rule for "borning" new cells. Higher order bits encode for an
9007 higher number of neighbor cells.
9008 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
9009 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
9011 Default value is "S23/B3", which is the original Conway's game of life
9012 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
9013 cells, and will born a new cell if there are three alive cells around
9017 Set the size of the output video. For the syntax of this option, check the
9018 "Video size" section in the ffmpeg-utils manual.
9020 If @option{filename} is specified, the size is set by default to the
9021 same size of the input file. If @option{size} is set, it must contain
9022 the size specified in the input file, and the initial grid defined in
9023 that file is centered in the larger resulting area.
9025 If a filename is not specified, the size value defaults to "320x240"
9026 (used for a randomly generated initial grid).
9029 If set to 1, stitch the left and right grid edges together, and the
9030 top and bottom edges also. Defaults to 1.
9033 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
9034 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
9035 value from 0 to 255.
9038 Set the color of living (or new born) cells.
9041 Set the color of dead cells. If @option{mold} is set, this is the first color
9042 used to represent a dead cell.
9045 Set mold color, for definitely dead and moldy cells.
9047 For the syntax of these 3 color options, check the "Color" section in the
9048 ffmpeg-utils manual.
9051 @subsection Examples
9055 Read a grid from @file{pattern}, and center it on a grid of size
9058 life=f=pattern:s=300x300
9062 Generate a random grid of size 200x200, with a fill ratio of 2/3:
9064 life=ratio=2/3:s=200x200
9068 Specify a custom rule for evolving a randomly generated grid:
9074 Full example with slow death effect (mold) using @command{ffplay}:
9076 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
9081 @anchor{haldclutsrc}
9085 @anchor{smptehdbars}
9087 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
9089 The @code{color} source provides an uniformly colored input.
9091 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
9092 @ref{haldclut} filter.
9094 The @code{nullsrc} source returns unprocessed video frames. It is
9095 mainly useful to be employed in analysis / debugging tools, or as the
9096 source for filters which ignore the input data.
9098 The @code{rgbtestsrc} source generates an RGB test pattern useful for
9099 detecting RGB vs BGR issues. You should see a red, green and blue
9100 stripe from top to bottom.
9102 The @code{smptebars} source generates a color bars pattern, based on
9103 the SMPTE Engineering Guideline EG 1-1990.
9105 The @code{smptehdbars} source generates a color bars pattern, based on
9106 the SMPTE RP 219-2002.
9108 The @code{testsrc} source generates a test video pattern, showing a
9109 color pattern, a scrolling gradient and a timestamp. This is mainly
9110 intended for testing purposes.
9112 The sources accept the following parameters:
9117 Specify the color of the source, only available in the @code{color}
9118 source. For the syntax of this option, check the "Color" section in the
9119 ffmpeg-utils manual.
9122 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
9123 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
9124 pixels to be used as identity matrix for 3D lookup tables. Each component is
9125 coded on a @code{1/(N*N)} scale.
9128 Specify the size of the sourced video. For the syntax of this option, check the
9129 "Video size" section in the ffmpeg-utils manual. The default value is
9132 This option is not available with the @code{haldclutsrc} filter.
9135 Specify the frame rate of the sourced video, as the number of frames
9136 generated per second. It has to be a string in the format
9137 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9138 number or a valid video frame rate abbreviation. The default value is
9142 Set the sample aspect ratio of the sourced video.
9145 Set the video duration of the sourced video. The accepted syntax is:
9147 [-]HH[:MM[:SS[.m...]]]
9150 Also see the the @code{av_parse_time()} function.
9152 If not specified, or the expressed duration is negative, the video is
9153 supposed to be generated forever.
9156 Set the number of decimals to show in the timestamp, only available in the
9157 @code{testsrc} source.
9159 The displayed timestamp value will correspond to the original
9160 timestamp value multiplied by the power of 10 of the specified
9161 value. Default value is 0.
9164 For example the following:
9166 testsrc=duration=5.3:size=qcif:rate=10
9169 will generate a video with a duration of 5.3 seconds, with size
9170 176x144 and a frame rate of 10 frames per second.
9172 The following graph description will generate a red source
9173 with an opacity of 0.2, with size "qcif" and a frame rate of 10
9176 color=c=red@@0.2:s=qcif:r=10
9179 If the input content is to be ignored, @code{nullsrc} can be used. The
9180 following command generates noise in the luminance plane by employing
9181 the @code{geq} filter:
9183 nullsrc=s=256x256, geq=random(1)*255:128:128
9186 @subsection Commands
9188 The @code{color} source supports the following commands:
9192 Set the color of the created image. Accepts the same syntax of the
9193 corresponding @option{color} option.
9196 @c man end VIDEO SOURCES
9198 @chapter Video Sinks
9199 @c man begin VIDEO SINKS
9201 Below is a description of the currently available video sinks.
9205 Buffer video frames, and make them available to the end of the filter
9208 This sink is mainly intended for programmatic use, in particular
9209 through the interface defined in @file{libavfilter/buffersink.h}
9210 or the options system.
9212 It accepts a pointer to an AVBufferSinkContext structure, which
9213 defines the incoming buffers' formats, to be passed as the opaque
9214 parameter to @code{avfilter_init_filter} for initialization.
9218 Null video sink: do absolutely nothing with the input video. It is
9219 mainly useful as a template and for use in analysis / debugging
9222 @c man end VIDEO SINKS
9224 @chapter Multimedia Filters
9225 @c man begin MULTIMEDIA FILTERS
9227 Below is a description of the currently available multimedia filters.
9229 @section avectorscope
9231 Convert input audio to a video output, representing the audio vector
9234 The filter is used to measure the difference between channels of stereo
9235 audio stream. A monoaural signal, consisting of identical left and right
9236 signal, results in straight vertical line. Any stereo separation is visible
9237 as a deviation from this line, creating a Lissajous figure.
9238 If the straight (or deviation from it) but horizontal line appears this
9239 indicates that the left and right channels are out of phase.
9241 The filter accepts the following options:
9245 Set the vectorscope mode.
9247 Available values are:
9250 Lissajous rotated by 45 degrees.
9253 Same as above but not rotated.
9256 Default value is @samp{lissajous}.
9259 Set the video size for the output. For the syntax of this option, check the "Video size"
9260 section in the ffmpeg-utils manual. Default value is @code{400x400}.
9263 Set the output frame rate. Default value is @code{25}.
9268 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
9269 Allowed range is @code{[0, 255]}.
9274 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
9275 Allowed range is @code{[0, 255]}.
9278 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
9281 @subsection Examples
9285 Complete example using @command{ffplay}:
9287 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9288 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
9294 Concatenate audio and video streams, joining them together one after the
9297 The filter works on segments of synchronized video and audio streams. All
9298 segments must have the same number of streams of each type, and that will
9299 also be the number of streams at output.
9301 The filter accepts the following options:
9306 Set the number of segments. Default is 2.
9309 Set the number of output video streams, that is also the number of video
9310 streams in each segment. Default is 1.
9313 Set the number of output audio streams, that is also the number of video
9314 streams in each segment. Default is 0.
9317 Activate unsafe mode: do not fail if segments have a different format.
9321 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
9322 @var{a} audio outputs.
9324 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
9325 segment, in the same order as the outputs, then the inputs for the second
9328 Related streams do not always have exactly the same duration, for various
9329 reasons including codec frame size or sloppy authoring. For that reason,
9330 related synchronized streams (e.g. a video and its audio track) should be
9331 concatenated at once. The concat filter will use the duration of the longest
9332 stream in each segment (except the last one), and if necessary pad shorter
9333 audio streams with silence.
9335 For this filter to work correctly, all segments must start at timestamp 0.
9337 All corresponding streams must have the same parameters in all segments; the
9338 filtering system will automatically select a common pixel format for video
9339 streams, and a common sample format, sample rate and channel layout for
9340 audio streams, but other settings, such as resolution, must be converted
9341 explicitly by the user.
9343 Different frame rates are acceptable but will result in variable frame rate
9344 at output; be sure to configure the output file to handle it.
9346 @subsection Examples
9350 Concatenate an opening, an episode and an ending, all in bilingual version
9351 (video in stream 0, audio in streams 1 and 2):
9353 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
9354 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
9355 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
9356 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
9360 Concatenate two parts, handling audio and video separately, using the
9361 (a)movie sources, and adjusting the resolution:
9363 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
9364 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
9365 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
9367 Note that a desync will happen at the stitch if the audio and video streams
9368 do not have exactly the same duration in the first file.
9374 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
9375 it unchanged. By default, it logs a message at a frequency of 10Hz with the
9376 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
9377 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
9379 The filter also has a video output (see the @var{video} option) with a real
9380 time graph to observe the loudness evolution. The graphic contains the logged
9381 message mentioned above, so it is not printed anymore when this option is set,
9382 unless the verbose logging is set. The main graphing area contains the
9383 short-term loudness (3 seconds of analysis), and the gauge on the right is for
9384 the momentary loudness (400 milliseconds).
9386 More information about the Loudness Recommendation EBU R128 on
9387 @url{http://tech.ebu.ch/loudness}.
9389 The filter accepts the following options:
9394 Activate the video output. The audio stream is passed unchanged whether this
9395 option is set or no. The video stream will be the first output stream if
9396 activated. Default is @code{0}.
9399 Set the video size. This option is for video only. For the syntax of this
9400 option, check the "Video size" section in the ffmpeg-utils manual. Default
9401 and minimum resolution is @code{640x480}.
9404 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
9405 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
9406 other integer value between this range is allowed.
9409 Set metadata injection. If set to @code{1}, the audio input will be segmented
9410 into 100ms output frames, each of them containing various loudness information
9411 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
9413 Default is @code{0}.
9416 Force the frame logging level.
9418 Available values are:
9421 information logging level
9423 verbose logging level
9426 By default, the logging level is set to @var{info}. If the @option{video} or
9427 the @option{metadata} options are set, it switches to @var{verbose}.
9432 Available modes can be cumulated (the option is a @code{flag} type). Possible
9436 Disable any peak mode (default).
9438 Enable sample-peak mode.
9440 Simple peak mode looking for the higher sample value. It logs a message
9441 for sample-peak (identified by @code{SPK}).
9443 Enable true-peak mode.
9445 If enabled, the peak lookup is done on an over-sampled version of the input
9446 stream for better peak accuracy. It logs a message for true-peak.
9447 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
9448 This mode requires a build with @code{libswresample}.
9453 @subsection Examples
9457 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
9459 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
9463 Run an analysis with @command{ffmpeg}:
9465 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
9469 @section interleave, ainterleave
9471 Temporally interleave frames from several inputs.
9473 @code{interleave} works with video inputs, @code{ainterleave} with audio.
9475 These filters read frames from several inputs and send the oldest
9476 queued frame to the output.
9478 Input streams must have a well defined, monotonically increasing frame
9481 In order to submit one frame to output, these filters need to enqueue
9482 at least one frame for each input, so they cannot work in case one
9483 input is not yet terminated and will not receive incoming frames.
9485 For example consider the case when one input is a @code{select} filter
9486 which always drop input frames. The @code{interleave} filter will keep
9487 reading from that input, but it will never be able to send new frames
9488 to output until the input will send an end-of-stream signal.
9490 Also, depending on inputs synchronization, the filters will drop
9491 frames in case one input receives more frames than the other ones, and
9492 the queue is already filled.
9494 These filters accept the following options:
9498 Set the number of different inputs, it is 2 by default.
9501 @subsection Examples
9505 Interleave frames belonging to different streams using @command{ffmpeg}:
9507 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
9511 Add flickering blur effect:
9513 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
9517 @section perms, aperms
9519 Set read/write permissions for the output frames.
9521 These filters are mainly aimed at developers to test direct path in the
9522 following filter in the filtergraph.
9524 The filters accept the following options:
9528 Select the permissions mode.
9530 It accepts the following values:
9533 Do nothing. This is the default.
9535 Set all the output frames read-only.
9537 Set all the output frames directly writable.
9539 Make the frame read-only if writable, and writable if read-only.
9541 Set each output frame read-only or writable randomly.
9545 Set the seed for the @var{random} mode, must be an integer included between
9546 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
9547 @code{-1}, the filter will try to use a good random seed on a best effort
9551 Note: in case of auto-inserted filter between the permission filter and the
9552 following one, the permission might not be received as expected in that
9553 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
9554 perms/aperms filter can avoid this problem.
9556 @section select, aselect
9558 Select frames to pass in output.
9560 This filter accepts the following options:
9565 Set expression, which is evaluated for each input frame.
9567 If the expression is evaluated to zero, the frame is discarded.
9569 If the evaluation result is negative or NaN, the frame is sent to the
9570 first output; otherwise it is sent to the output with index
9571 @code{ceil(val)-1}, assuming that the input index starts from 0.
9573 For example a value of @code{1.2} corresponds to the output with index
9574 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
9577 Set the number of outputs. The output to which to send the selected
9578 frame is based on the result of the evaluation. Default value is 1.
9581 The expression can contain the following constants:
9585 The (sequential) number of the filtered frame, starting from 0.
9588 The (sequential) number of the selected frame, starting from 0.
9590 @item prev_selected_n
9591 The sequential number of the last selected frame. It's NAN if undefined.
9594 The timebase of the input timestamps.
9597 The PTS (Presentation TimeStamp) of the filtered video frame,
9598 expressed in @var{TB} units. It's NAN if undefined.
9601 The PTS of the filtered video frame,
9602 expressed in seconds. It's NAN if undefined.
9605 The PTS of the previously filtered video frame. It's NAN if undefined.
9607 @item prev_selected_pts
9608 The PTS of the last previously filtered video frame. It's NAN if undefined.
9610 @item prev_selected_t
9611 The PTS of the last previously selected video frame. It's NAN if undefined.
9614 The PTS of the first video frame in the video. It's NAN if undefined.
9617 The time of the first video frame in the video. It's NAN if undefined.
9619 @item pict_type @emph{(video only)}
9620 The type of the filtered frame. It can assume one of the following
9632 @item interlace_type @emph{(video only)}
9633 The frame interlace type. It can assume one of the following values:
9636 The frame is progressive (not interlaced).
9638 The frame is top-field-first.
9640 The frame is bottom-field-first.
9643 @item consumed_sample_n @emph{(audio only)}
9644 the number of selected samples before the current frame
9646 @item samples_n @emph{(audio only)}
9647 the number of samples in the current frame
9649 @item sample_rate @emph{(audio only)}
9650 the input sample rate
9653 This is 1 if the filtered frame is a key-frame, 0 otherwise.
9656 the position in the file of the filtered frame, -1 if the information
9657 is not available (e.g. for synthetic video)
9659 @item scene @emph{(video only)}
9660 value between 0 and 1 to indicate a new scene; a low value reflects a low
9661 probability for the current frame to introduce a new scene, while a higher
9662 value means the current frame is more likely to be one (see the example below)
9666 The default value of the select expression is "1".
9668 @subsection Examples
9672 Select all frames in input:
9677 The example above is the same as:
9689 Select only I-frames:
9691 select='eq(pict_type\,I)'
9695 Select one frame every 100:
9697 select='not(mod(n\,100))'
9701 Select only frames contained in the 10-20 time interval:
9703 select=between(t\,10\,20)
9707 Select only I frames contained in the 10-20 time interval:
9709 select=between(t\,10\,20)*eq(pict_type\,I)
9713 Select frames with a minimum distance of 10 seconds:
9715 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
9719 Use aselect to select only audio frames with samples number > 100:
9721 aselect='gt(samples_n\,100)'
9725 Create a mosaic of the first scenes:
9727 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
9730 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
9734 Send even and odd frames to separate outputs, and compose them:
9736 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
9740 @section sendcmd, asendcmd
9742 Send commands to filters in the filtergraph.
9744 These filters read commands to be sent to other filters in the
9747 @code{sendcmd} must be inserted between two video filters,
9748 @code{asendcmd} must be inserted between two audio filters, but apart
9749 from that they act the same way.
9751 The specification of commands can be provided in the filter arguments
9752 with the @var{commands} option, or in a file specified by the
9753 @var{filename} option.
9755 These filters accept the following options:
9758 Set the commands to be read and sent to the other filters.
9760 Set the filename of the commands to be read and sent to the other
9764 @subsection Commands syntax
9766 A commands description consists of a sequence of interval
9767 specifications, comprising a list of commands to be executed when a
9768 particular event related to that interval occurs. The occurring event
9769 is typically the current frame time entering or leaving a given time
9772 An interval is specified by the following syntax:
9774 @var{START}[-@var{END}] @var{COMMANDS};
9777 The time interval is specified by the @var{START} and @var{END} times.
9778 @var{END} is optional and defaults to the maximum time.
9780 The current frame time is considered within the specified interval if
9781 it is included in the interval [@var{START}, @var{END}), that is when
9782 the time is greater or equal to @var{START} and is lesser than
9785 @var{COMMANDS} consists of a sequence of one or more command
9786 specifications, separated by ",", relating to that interval. The
9787 syntax of a command specification is given by:
9789 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
9792 @var{FLAGS} is optional and specifies the type of events relating to
9793 the time interval which enable sending the specified command, and must
9794 be a non-null sequence of identifier flags separated by "+" or "|" and
9795 enclosed between "[" and "]".
9797 The following flags are recognized:
9800 The command is sent when the current frame timestamp enters the
9801 specified interval. In other words, the command is sent when the
9802 previous frame timestamp was not in the given interval, and the
9806 The command is sent when the current frame timestamp leaves the
9807 specified interval. In other words, the command is sent when the
9808 previous frame timestamp was in the given interval, and the
9812 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
9815 @var{TARGET} specifies the target of the command, usually the name of
9816 the filter class or a specific filter instance name.
9818 @var{COMMAND} specifies the name of the command for the target filter.
9820 @var{ARG} is optional and specifies the optional list of argument for
9821 the given @var{COMMAND}.
9823 Between one interval specification and another, whitespaces, or
9824 sequences of characters starting with @code{#} until the end of line,
9825 are ignored and can be used to annotate comments.
9827 A simplified BNF description of the commands specification syntax
9830 @var{COMMAND_FLAG} ::= "enter" | "leave"
9831 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
9832 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
9833 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
9834 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
9835 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
9838 @subsection Examples
9842 Specify audio tempo change at second 4:
9844 asendcmd=c='4.0 atempo tempo 1.5',atempo
9848 Specify a list of drawtext and hue commands in a file.
9850 # show text in the interval 5-10
9851 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
9852 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
9854 # desaturate the image in the interval 15-20
9855 15.0-20.0 [enter] hue s 0,
9856 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
9858 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
9860 # apply an exponential saturation fade-out effect, starting from time 25
9861 25 [enter] hue s exp(25-t)
9864 A filtergraph allowing to read and process the above command list
9865 stored in a file @file{test.cmd}, can be specified with:
9867 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
9872 @section setpts, asetpts
9874 Change the PTS (presentation timestamp) of the input frames.
9876 @code{setpts} works on video frames, @code{asetpts} on audio frames.
9878 This filter accepts the following options:
9883 The expression which is evaluated for each frame to construct its timestamp.
9887 The expression is evaluated through the eval API and can contain the following
9892 frame rate, only defined for constant frame-rate video
9895 The presentation timestamp in input
9898 The count of the input frame for video or the number of consumed samples,
9899 not including the current frame for audio, starting from 0.
9901 @item NB_CONSUMED_SAMPLES
9902 The number of consumed samples, not including the current frame (only
9906 The number of samples in the current frame (only audio)
9908 @item SAMPLE_RATE, SR
9909 The audio sample rate.
9912 The PTS of the first frame.
9915 the time in seconds of the first frame
9918 State whether the current frame is interlaced.
9921 the time in seconds of the current frame
9924 original position in the file of the frame, or undefined if undefined
9925 for the current frame
9928 The previous input PTS.
9931 previous input time in seconds
9934 The previous output PTS.
9937 previous output time in seconds
9940 The wallclock (RTC) time in microseconds.. This is deprecated, use time(0)
9944 The wallclock (RTC) time at the start of the movie in microseconds.
9947 The timebase of the input timestamps.
9951 @subsection Examples
9955 Start counting PTS from zero
9961 Apply fast motion effect:
9967 Apply slow motion effect:
9973 Set fixed rate of 25 frames per second:
9979 Set fixed rate 25 fps with some jitter:
9981 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
9985 Apply an offset of 10 seconds to the input PTS:
9991 Generate timestamps from a "live source" and rebase onto the current timebase:
9993 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
9997 Generate timestamps by counting samples:
10004 @section settb, asettb
10006 Set the timebase to use for the output frames timestamps.
10007 It is mainly useful for testing timebase configuration.
10009 It accepts the following parameters:
10014 The expression which is evaluated into the output timebase.
10018 The value for @option{tb} is an arithmetic expression representing a
10019 rational. The expression can contain the constants "AVTB" (the default
10020 timebase), "intb" (the input timebase) and "sr" (the sample rate,
10021 audio only). Default value is "intb".
10023 @subsection Examples
10027 Set the timebase to 1/25:
10033 Set the timebase to 1/10:
10039 Set the timebase to 1001/1000:
10045 Set the timebase to 2*intb:
10051 Set the default timebase value:
10057 @section showspectrum
10059 Convert input audio to a video output, representing the audio frequency
10062 The filter accepts the following options:
10066 Specify the video size for the output. For the syntax of this option, check
10067 the "Video size" section in the ffmpeg-utils manual. Default value is
10071 Specify if the spectrum should slide along the window. Default value is
10075 Specify display mode.
10077 It accepts the following values:
10080 all channels are displayed in the same row
10082 all channels are displayed in separate rows
10085 Default value is @samp{combined}.
10088 Specify display color mode.
10090 It accepts the following values:
10093 each channel is displayed in a separate color
10095 each channel is is displayed using the same color scheme
10098 Default value is @samp{channel}.
10101 Specify scale used for calculating intensity color values.
10103 It accepts the following values:
10108 square root, default
10115 Default value is @samp{sqrt}.
10118 Set saturation modifier for displayed colors. Negative values provide
10119 alternative color scheme. @code{0} is no saturation at all.
10120 Saturation must be in [-10.0, 10.0] range.
10121 Default value is @code{1}.
10124 Set window function.
10126 It accepts the following values:
10129 No samples pre-processing (do not expect this to be faster)
10138 Default value is @code{hann}.
10141 The usage is very similar to the showwaves filter; see the examples in that
10144 @subsection Examples
10148 Large window with logarithmic color scaling:
10150 showspectrum=s=1280x480:scale=log
10154 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
10156 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10157 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
10163 Convert input audio to a video output, representing the samples waves.
10165 The filter accepts the following options:
10169 Specify the video size for the output. For the syntax of this option, check
10170 the "Video size" section in the ffmpeg-utils manual. Default value
10176 Available values are:
10179 Draw a point for each sample.
10182 Draw a vertical line for each sample.
10185 Default value is @code{point}.
10188 Set the number of samples which are printed on the same column. A
10189 larger value will decrease the frame rate. Must be a positive
10190 integer. This option can be set only if the value for @var{rate}
10191 is not explicitly specified.
10194 Set the (approximate) output frame rate. This is done by setting the
10195 option @var{n}. Default value is "25".
10199 @subsection Examples
10203 Output the input file audio and the corresponding video representation
10206 amovie=a.mp3,asplit[out0],showwaves[out1]
10210 Create a synthetic signal and show it with showwaves, forcing a
10211 frame rate of 30 frames per second:
10213 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
10217 @section split, asplit
10219 Split input into several identical outputs.
10221 @code{asplit} works with audio input, @code{split} with video.
10223 The filter accepts a single parameter which specifies the number of outputs. If
10224 unspecified, it defaults to 2.
10226 @subsection Examples
10230 Create two separate outputs from the same input:
10232 [in] split [out0][out1]
10236 To create 3 or more outputs, you need to specify the number of
10239 [in] asplit=3 [out0][out1][out2]
10243 Create two separate outputs from the same input, one cropped and
10246 [in] split [splitout1][splitout2];
10247 [splitout1] crop=100:100:0:0 [cropout];
10248 [splitout2] pad=200:200:100:100 [padout];
10252 Create 5 copies of the input audio with @command{ffmpeg}:
10254 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
10260 Receive commands sent through a libzmq client, and forward them to
10261 filters in the filtergraph.
10263 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
10264 must be inserted between two video filters, @code{azmq} between two
10267 To enable these filters you need to install the libzmq library and
10268 headers and configure FFmpeg with @code{--enable-libzmq}.
10270 For more information about libzmq see:
10271 @url{http://www.zeromq.org/}
10273 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
10274 receives messages sent through a network interface defined by the
10275 @option{bind_address} option.
10277 The received message must be in the form:
10279 @var{TARGET} @var{COMMAND} [@var{ARG}]
10282 @var{TARGET} specifies the target of the command, usually the name of
10283 the filter class or a specific filter instance name.
10285 @var{COMMAND} specifies the name of the command for the target filter.
10287 @var{ARG} is optional and specifies the optional argument list for the
10288 given @var{COMMAND}.
10290 Upon reception, the message is processed and the corresponding command
10291 is injected into the filtergraph. Depending on the result, the filter
10292 will send a reply to the client, adopting the format:
10294 @var{ERROR_CODE} @var{ERROR_REASON}
10298 @var{MESSAGE} is optional.
10300 @subsection Examples
10302 Look at @file{tools/zmqsend} for an example of a zmq client which can
10303 be used to send commands processed by these filters.
10305 Consider the following filtergraph generated by @command{ffplay}
10307 ffplay -dumpgraph 1 -f lavfi "
10308 color=s=100x100:c=red [l];
10309 color=s=100x100:c=blue [r];
10310 nullsrc=s=200x100, zmq [bg];
10311 [bg][l] overlay [bg+l];
10312 [bg+l][r] overlay=x=100 "
10315 To change the color of the left side of the video, the following
10316 command can be used:
10318 echo Parsed_color_0 c yellow | tools/zmqsend
10321 To change the right side:
10323 echo Parsed_color_1 c pink | tools/zmqsend
10326 @c man end MULTIMEDIA FILTERS
10328 @chapter Multimedia Sources
10329 @c man begin MULTIMEDIA SOURCES
10331 Below is a description of the currently available multimedia sources.
10335 This is the same as @ref{movie} source, except it selects an audio
10341 Read audio and/or video stream(s) from a movie container.
10343 It accepts the following parameters:
10347 The name of the resource to read (not necessarily a file; it can also be a
10348 device or a stream accessed through some protocol).
10350 @item format_name, f
10351 Specifies the format assumed for the movie to read, and can be either
10352 the name of a container or an input device. If not specified, the
10353 format is guessed from @var{movie_name} or by probing.
10355 @item seek_point, sp
10356 Specifies the seek point in seconds. The frames will be output
10357 starting from this seek point. The parameter is evaluated with
10358 @code{av_strtod}, so the numerical value may be suffixed by an IS
10359 postfix. The default value is "0".
10362 Specifies the streams to read. Several streams can be specified,
10363 separated by "+". The source will then have as many outputs, in the
10364 same order. The syntax is explained in the ``Stream specifiers''
10365 section in the ffmpeg manual. Two special names, "dv" and "da" specify
10366 respectively the default (best suited) video and audio stream. Default
10367 is "dv", or "da" if the filter is called as "amovie".
10369 @item stream_index, si
10370 Specifies the index of the video stream to read. If the value is -1,
10371 the most suitable video stream will be automatically selected. The default
10372 value is "-1". Deprecated. If the filter is called "amovie", it will select
10373 audio instead of video.
10376 Specifies how many times to read the stream in sequence.
10377 If the value is less than 1, the stream will be read again and again.
10378 Default value is "1".
10380 Note that when the movie is looped the source timestamps are not
10381 changed, so it will generate non monotonically increasing timestamps.
10384 It allows overlaying a second video on top of the main input of
10385 a filtergraph, as shown in this graph:
10387 input -----------> deltapts0 --> overlay --> output
10390 movie --> scale--> deltapts1 -------+
10392 @subsection Examples
10396 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
10397 on top of the input labelled "in":
10399 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
10400 [in] setpts=PTS-STARTPTS [main];
10401 [main][over] overlay=16:16 [out]
10405 Read from a video4linux2 device, and overlay it on top of the input
10408 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
10409 [in] setpts=PTS-STARTPTS [main];
10410 [main][over] overlay=16:16 [out]
10414 Read the first video stream and the audio stream with id 0x81 from
10415 dvd.vob; the video is connected to the pad named "video" and the audio is
10416 connected to the pad named "audio":
10418 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
10422 @c man end MULTIMEDIA SOURCES