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.
700 Note that this filter only supports float samples (the @var{amerge}
701 and @var{pan} audio filters support many formats). If the @var{amix}
702 input has integer samples then @ref{aresample} will be automatically
703 inserted to perform the conversion to float samples.
707 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
709 will mix 3 input audio streams to a single output with the same duration as the
710 first input and a dropout transition time of 3 seconds.
712 It accepts the following parameters:
716 The number of inputs. If unspecified, it defaults to 2.
719 How to determine the end-of-stream.
723 The duration of the longest input. (default)
726 The duration of the shortest input.
729 The duration of the first input.
733 @item dropout_transition
734 The transition time, in seconds, for volume renormalization when an input
735 stream ends. The default value is 2 seconds.
741 Pass the audio source unchanged to the output.
745 Pad the end of an audio stream with silence.
747 This can be used together with @command{ffmpeg} @option{-shortest} to
748 extend audio streams to the same length as the video stream.
750 A description of the accepted options follows.
754 Set silence packet size. Default value is 4096.
757 Set the number of samples of silence to add to the end. After the
758 value is reached, the stream is terminated. This option is mutually
759 exclusive with @option{whole_len}.
762 Set the minimum total number of samples in the output audio stream. If
763 the value is longer than the input audio length, silence is added to
764 the end, until the value is reached. This option is mutually exclusive
765 with @option{pad_len}.
768 If neither the @option{pad_len} nor the @option{whole_len} option is
769 set, the filter will add silence to the end of the input stream
776 Add 1024 samples of silence to the end of the input:
782 Make sure the audio output will contain at least 10000 samples, pad
783 the input with silence if required:
789 Use @command{ffmpeg} to pad the audio input with silence, so that the
790 video stream will always result the shortest and will be converted
791 until the end in the output file when using the @option{shortest}
794 ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad" -shortest OUTPUT
799 Add a phasing effect to the input audio.
801 A phaser filter creates series of peaks and troughs in the frequency spectrum.
802 The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect.
804 A description of the accepted parameters follows.
808 Set input gain. Default is 0.4.
811 Set output gain. Default is 0.74
814 Set delay in milliseconds. Default is 3.0.
817 Set decay. Default is 0.4.
820 Set modulation speed in Hz. Default is 0.5.
823 Set modulation type. Default is triangular.
825 It accepts the following values:
835 Resample the input audio to the specified parameters, using the
836 libswresample library. If none are specified then the filter will
837 automatically convert between its input and output.
839 This filter is also able to stretch/squeeze the audio data to make it match
840 the timestamps or to inject silence / cut out audio to make it match the
841 timestamps, do a combination of both or do neither.
843 The filter accepts the syntax
844 [@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate}
845 expresses a sample rate and @var{resampler_options} is a list of
846 @var{key}=@var{value} pairs, separated by ":". See the
847 ffmpeg-resampler manual for the complete list of supported options.
853 Resample the input audio to 44100Hz:
859 Stretch/squeeze samples to the given timestamps, with a maximum of 1000
860 samples per second compensation:
866 @section asetnsamples
868 Set the number of samples per each output audio frame.
870 The last output packet may contain a different number of samples, as
871 the filter will flush all the remaining samples when the input audio
874 The filter accepts the following options:
878 @item nb_out_samples, n
879 Set the number of frames per each output audio frame. The number is
880 intended as the number of samples @emph{per each channel}.
881 Default value is 1024.
884 If set to 1, the filter will pad the last audio frame with zeroes, so
885 that the last frame will contain the same number of samples as the
886 previous ones. Default value is 1.
889 For example, to set the number of per-frame samples to 1234 and
890 disable padding for the last frame, use:
892 asetnsamples=n=1234:p=0
897 Set the sample rate without altering the PCM data.
898 This will result in a change of speed and pitch.
900 The filter accepts the following options:
904 Set the output sample rate. Default is 44100 Hz.
909 Show a line containing various information for each input audio frame.
910 The input audio is not modified.
912 The shown line contains a sequence of key/value pairs of the form
913 @var{key}:@var{value}.
915 The following values are shown in the output:
919 The (sequential) number of the input frame, starting from 0.
922 The presentation timestamp of the input frame, in time base units; the time base
923 depends on the filter input pad, and is usually 1/@var{sample_rate}.
926 The presentation timestamp of the input frame in seconds.
929 position of the frame in the input stream, -1 if this information in
930 unavailable and/or meaningless (for example in case of synthetic audio)
939 The sample rate for the audio frame.
942 The number of samples (per channel) in the frame.
945 The Adler-32 checksum (printed in hexadecimal) of the audio data. For planar
946 audio, the data is treated as if all the planes were concatenated.
948 @item plane_checksums
949 A list of Adler-32 checksums for each data plane.
954 Display time domain statistical information about the audio channels.
955 Statistics are calculated and displayed for each audio channel and,
956 where applicable, an overall figure is also given.
958 It accepts the following option:
961 Short window length in seconds, used for peak and trough RMS measurement.
962 Default is @code{0.05} (50 miliseconds). Allowed range is @code{[0.1 - 10]}.
965 A description of each shown parameter follows:
969 Mean amplitude displacement from zero.
972 Minimal sample level.
975 Maximal sample level.
979 Standard peak and RMS level measured in dBFS.
983 Peak and trough values for RMS level measured over a short window.
986 Standard ratio of peak to RMS level (note: not in dB).
989 Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels
990 (i.e. either @var{Min level} or @var{Max level}).
993 Number of occasions (not the number of samples) that the signal attained either
994 @var{Min level} or @var{Max level}.
999 Forward two audio streams and control the order the buffers are forwarded.
1001 The filter accepts the following options:
1005 Set the expression deciding which stream should be
1006 forwarded next: if the result is negative, the first stream is forwarded; if
1007 the result is positive or zero, the second stream is forwarded. It can use
1008 the following variables:
1012 number of buffers forwarded so far on each stream
1014 number of samples forwarded so far on each stream
1016 current timestamp of each stream
1019 The default value is @code{t1-t2}, which means to always forward the stream
1020 that has a smaller timestamp.
1023 @subsection Examples
1025 Stress-test @code{amerge} by randomly sending buffers on the wrong
1026 input, while avoiding too much of a desynchronization:
1028 amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
1029 [a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
1035 Synchronize audio data with timestamps by squeezing/stretching it and/or
1036 dropping samples/adding silence when needed.
1038 This filter is not built by default, please use @ref{aresample} to do squeezing/stretching.
1040 It accepts the following parameters:
1044 Enable stretching/squeezing the data to make it match the timestamps. Disabled
1045 by default. When disabled, time gaps are covered with silence.
1048 The minimum difference between timestamps and audio data (in seconds) to trigger
1049 adding/dropping samples. The default value is 0.1. If you get an imperfect
1050 sync with this filter, try setting this parameter to 0.
1053 The maximum compensation in samples per second. Only relevant with compensate=1.
1054 The default value is 500.
1057 Assume that the first PTS should be this value. The time base is 1 / sample
1058 rate. This allows for padding/trimming at the start of the stream. By default,
1059 no assumption is made about the first frame's expected PTS, so no padding or
1060 trimming is done. For example, this could be set to 0 to pad the beginning with
1061 silence if an audio stream starts after the video stream or to trim any samples
1062 with a negative PTS due to encoder delay.
1070 The filter accepts exactly one parameter, the audio tempo. If not
1071 specified then the filter will assume nominal 1.0 tempo. Tempo must
1072 be in the [0.5, 2.0] range.
1074 @subsection Examples
1078 Slow down audio to 80% tempo:
1084 To speed up audio to 125% tempo:
1092 Trim the input so that the output contains one continuous subpart of the input.
1094 It accepts the following parameters:
1097 Timestamp (in seconds) of the start of the section to keep. I.e. the audio
1098 sample with the timestamp @var{start} will be the first sample in the output.
1101 Specify time of the first audio sample that will be dropped, i.e. the
1102 audio sample immediately preceding the one with the timestamp @var{end} will be
1103 the last sample in the output.
1106 Same as @var{start}, except this option sets the start timestamp in samples
1110 Same as @var{end}, except this option sets the end timestamp in samples instead
1114 The maximum duration of the output in seconds.
1117 The number of the first sample that should be output.
1120 The number of the first sample that should be dropped.
1123 @option{start}, @option{end}, @option{duration} are expressed as time
1124 duration specifications, check the "Time duration" section in the
1125 ffmpeg-utils manual.
1127 Note that the first two sets of the start/end options and the @option{duration}
1128 option look at the frame timestamp, while the _sample options simply count the
1129 samples that pass through the filter. So start/end_pts and start/end_sample will
1130 give different results when the timestamps are wrong, inexact or do not start at
1131 zero. Also note that this filter does not modify the timestamps. If you wish
1132 to have the output timestamps start at zero, insert the asetpts filter after the
1135 If multiple start or end options are set, this filter tries to be greedy and
1136 keep all samples that match at least one of the specified constraints. To keep
1137 only the part that matches all the constraints at once, chain multiple atrim
1140 The defaults are such that all the input is kept. So it is possible to set e.g.
1141 just the end values to keep everything before the specified time.
1146 Drop everything except the second minute of input:
1148 ffmpeg -i INPUT -af atrim=60:120
1152 Keep only the first 1000 samples:
1154 ffmpeg -i INPUT -af atrim=end_sample=1000
1161 Apply a two-pole Butterworth band-pass filter with central
1162 frequency @var{frequency}, and (3dB-point) band-width width.
1163 The @var{csg} option selects a constant skirt gain (peak gain = Q)
1164 instead of the default: constant 0dB peak gain.
1165 The filter roll off at 6dB per octave (20dB per decade).
1167 The filter accepts the following options:
1171 Set the filter's central frequency. Default is @code{3000}.
1174 Constant skirt gain if set to 1. Defaults to 0.
1177 Set method to specify band-width of filter.
1190 Specify the band-width of a filter in width_type units.
1195 Apply a two-pole Butterworth band-reject filter with central
1196 frequency @var{frequency}, and (3dB-point) band-width @var{width}.
1197 The filter roll off at 6dB per octave (20dB per decade).
1199 The filter accepts the following options:
1203 Set the filter's central frequency. Default is @code{3000}.
1206 Set method to specify band-width of filter.
1219 Specify the band-width of a filter in width_type units.
1224 Boost or cut the bass (lower) frequencies of the audio using a two-pole
1225 shelving filter with a response similar to that of a standard
1226 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1228 The filter accepts the following options:
1232 Give the gain at 0 Hz. Its useful range is about -20
1233 (for a large cut) to +20 (for a large boost).
1234 Beware of clipping when using a positive gain.
1237 Set the filter's central frequency and so can be used
1238 to extend or reduce the frequency range to be boosted or cut.
1239 The default value is @code{100} Hz.
1242 Set method to specify band-width of filter.
1255 Determine how steep is the filter's shelf transition.
1260 Apply a biquad IIR filter with the given coefficients.
1261 Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2}
1262 are the numerator and denominator coefficients respectively.
1265 Bauer stereo to binaural transformation, which improves headphone listening of
1266 stereo audio records.
1268 It accepts the following parameters:
1272 Pre-defined crossfeed level.
1276 Default level (fcut=700, feed=50).
1279 Chu Moy circuit (fcut=700, feed=60).
1282 Jan Meier circuit (fcut=650, feed=95).
1287 Cut frequency (in Hz).
1296 Remap input channels to new locations.
1298 It accepts the following parameters:
1300 @item channel_layout
1301 The channel layout of the output stream.
1304 Map channels from input to output. The argument is a '|'-separated list of
1305 mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
1306 @var{in_channel} form. @var{in_channel} can be either the name of the input
1307 channel (e.g. FL for front left) or its index in the input channel layout.
1308 @var{out_channel} is the name of the output channel or its index in the output
1309 channel layout. If @var{out_channel} is not given then it is implicitly an
1310 index, starting with zero and increasing by one for each mapping.
1313 If no mapping is present, the filter will implicitly map input channels to
1314 output channels, preserving indices.
1316 For example, assuming a 5.1+downmix input MOV file,
1318 ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav
1320 will create an output WAV file tagged as stereo from the downmix channels of
1323 To fix a 5.1 WAV improperly encoded in AAC's native channel order
1325 ffmpeg -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1' out.wav
1328 @section channelsplit
1330 Split each channel from an input audio stream into a separate output stream.
1332 It accepts the following parameters:
1334 @item channel_layout
1335 The channel layout of the input stream. The default is "stereo".
1338 For example, assuming a stereo input MP3 file,
1340 ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
1342 will create an output Matroska file with two audio streams, one containing only
1343 the left channel and the other the right channel.
1345 Split a 5.1 WAV file into per-channel files:
1347 ffmpeg -i in.wav -filter_complex
1348 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
1349 -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
1350 front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
1355 Compress or expand the audio's dynamic range.
1357 It accepts the following parameters:
1363 A list of times in seconds for each channel over which the instantaneous level
1364 of the input signal is averaged to determine its volume. @var{attacks} refers to
1365 increase of volume and @var{decays} refers to decrease of volume. For most
1366 situations, the attack time (response to the audio getting louder) should be
1367 shorter than the decay time, because the human ear is more sensitive to sudden
1368 loud audio than sudden soft audio. A typical value for attack is 0.3 seconds and
1369 a typical value for decay is 0.8 seconds.
1372 A list of points for the transfer function, specified in dB relative to the
1373 maximum possible signal amplitude. Each key points list must be defined using
1374 the following syntax: @code{x0/y0|x1/y1|x2/y2|....} or
1375 @code{x0/y0 x1/y1 x2/y2 ....}
1377 The input values must be in strictly increasing order but the transfer function
1378 does not have to be monotonically rising. The point @code{0/0} is assumed but
1379 may be overridden (by @code{0/out-dBn}). Typical values for the transfer
1380 function are @code{-70/-70|-60/-20}.
1383 Set the curve radius in dB for all joints. It defaults to 0.01.
1386 Set the additional gain in dB to be applied at all points on the transfer
1387 function. This allows for easy adjustment of the overall gain.
1391 Set an initial volume, in dB, to be assumed for each channel when filtering
1392 starts. This permits the user to supply a nominal level initially, so that, for
1393 example, a very large gain is not applied to initial signal levels before the
1394 companding has begun to operate. A typical value for audio which is initially
1395 quiet is -90 dB. It defaults to 0.
1398 Set a delay, in seconds. The input audio is analyzed immediately, but audio is
1399 delayed before being fed to the volume adjuster. Specifying a delay
1400 approximately equal to the attack/decay times allows the filter to effectively
1401 operate in predictive rather than reactive mode. It defaults to 0.
1405 @subsection Examples
1409 Make music with both quiet and loud passages suitable for listening to in a
1412 compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2
1416 A noise gate for when the noise is at a lower level than the signal:
1418 compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1
1422 Here is another noise gate, this time for when the noise is at a higher level
1423 than the signal (making it, in some ways, similar to squelch):
1425 compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1
1431 Make audio easier to listen to on headphones.
1433 This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
1434 so that when listened to on headphones the stereo image is moved from
1435 inside your head (standard for headphones) to outside and in front of
1436 the listener (standard for speakers).
1442 Apply a two-pole peaking equalisation (EQ) filter. With this
1443 filter, the signal-level at and around a selected frequency can
1444 be increased or decreased, whilst (unlike bandpass and bandreject
1445 filters) that at all other frequencies is unchanged.
1447 In order to produce complex equalisation curves, this filter can
1448 be given several times, each with a different central frequency.
1450 The filter accepts the following options:
1454 Set the filter's central frequency in Hz.
1457 Set method to specify band-width of filter.
1470 Specify the band-width of a filter in width_type units.
1473 Set the required gain or attenuation in dB.
1474 Beware of clipping when using a positive gain.
1477 @subsection Examples
1480 Attenuate 10 dB at 1000 Hz, with a bandwidth of 200 Hz:
1482 equalizer=f=1000:width_type=h:width=200:g=-10
1486 Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz with Q 2:
1488 equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5
1493 Apply a flanging effect to the audio.
1495 The filter accepts the following options:
1499 Set base delay in milliseconds. Range from 0 to 30. Default value is 0.
1502 Set added swep delay in milliseconds. Range from 0 to 10. Default value is 2.
1505 Set percentage regeneneration (delayed signal feedback). Range from -95 to 95.
1509 Set percentage of delayed signal mixed with original. Range from 0 to 100.
1513 Set sweeps per second (Hz). Range from 0.1 to 10. Default value is 0.5.
1516 Set swept wave shape, can be @var{triangular} or @var{sinusoidal}.
1517 Default value is @var{sinusoidal}.
1520 Set swept wave percentage-shift for multi channel. Range from 0 to 100.
1521 Default value is 25.
1524 Set delay-line interpolation, @var{linear} or @var{quadratic}.
1525 Default is @var{linear}.
1530 Apply a high-pass filter with 3dB point frequency.
1531 The filter can be either single-pole, or double-pole (the default).
1532 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1534 The filter accepts the following options:
1538 Set frequency in Hz. Default is 3000.
1541 Set number of poles. Default is 2.
1544 Set method to specify band-width of filter.
1557 Specify the band-width of a filter in width_type units.
1558 Applies only to double-pole filter.
1559 The default is 0.707q and gives a Butterworth response.
1564 Join multiple input streams into one multi-channel stream.
1566 It accepts the following parameters:
1570 The number of input streams. It defaults to 2.
1572 @item channel_layout
1573 The desired output channel layout. It defaults to stereo.
1576 Map channels from inputs to output. The argument is a '|'-separated list of
1577 mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
1578 form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
1579 can be either the name of the input channel (e.g. FL for front left) or its
1580 index in the specified input stream. @var{out_channel} is the name of the output
1584 The filter will attempt to guess the mappings when they are not specified
1585 explicitly. It does so by first trying to find an unused matching input channel
1586 and if that fails it picks the first unused input channel.
1588 Join 3 inputs (with properly set channel layouts):
1590 ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
1593 Build a 5.1 output from 6 single-channel streams:
1595 ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
1596 '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'
1602 Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.
1604 To enable compilation of this filter you need to configure FFmpeg with
1605 @code{--enable-ladspa}.
1609 Specifies the name of LADSPA plugin library to load. If the environment
1610 variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in
1611 each one of the directories specified by the colon separated list in
1612 @env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in
1613 this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/},
1614 @file{/usr/lib/ladspa/}.
1617 Specifies the plugin within the library. Some libraries contain only
1618 one plugin, but others contain many of them. If this is not set filter
1619 will list all available plugins within the specified library.
1622 Set the '|' separated list of controls which are zero or more floating point
1623 values that determine the behavior of the loaded plugin (for example delay,
1625 Controls need to be defined using the following syntax:
1626 c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where
1627 @var{valuei} is the value set on the @var{i}-th control.
1628 If @option{controls} is set to @code{help}, all available controls and
1629 their valid ranges are printed.
1631 @item sample_rate, s
1632 Specify the sample rate, default to 44100. Only used if plugin have
1636 Set the number of samples per channel per each output frame, default
1637 is 1024. Only used if plugin have zero inputs.
1640 Set the minimum duration of the sourced audio. See the function
1641 @code{av_parse_time()} for the accepted format, also check the "Time duration"
1642 section in the ffmpeg-utils manual.
1643 Note that the resulting duration may be greater than the specified duration,
1644 as the generated audio is always cut at the end of a complete frame.
1645 If not specified, or the expressed duration is negative, the audio is
1646 supposed to be generated forever.
1647 Only used if plugin have zero inputs.
1651 @subsection Examples
1655 List all available plugins within amp (LADSPA example plugin) library:
1661 List all available controls and their valid ranges for @code{vcf_notch}
1662 plugin from @code{VCF} library:
1664 ladspa=f=vcf:p=vcf_notch:c=help
1668 Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT)
1671 ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12
1675 Add reverberation to the audio using TAP-plugins
1676 (Tom's Audio Processing plugins):
1678 ladspa=file=tap_reverb:tap_reverb
1682 Generate white noise, with 0.2 amplitude:
1684 ladspa=file=cmt:noise_source_white:c=c0=.2
1688 Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the
1689 @code{C* Audio Plugin Suite} (CAPS) library:
1691 ladspa=file=caps:Click:c=c1=20'
1695 Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect:
1697 ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2
1701 @subsection Commands
1703 This filter supports the following commands:
1706 Modify the @var{N}-th control value.
1708 If the specified value is not valid, it is ignored and prior one is kept.
1713 Apply a low-pass filter with 3dB point frequency.
1714 The filter can be either single-pole or double-pole (the default).
1715 The filter roll off at 6dB per pole per octave (20dB per pole per decade).
1717 The filter accepts the following options:
1721 Set frequency in Hz. Default is 500.
1724 Set number of poles. Default is 2.
1727 Set method to specify band-width of filter.
1740 Specify the band-width of a filter in width_type units.
1741 Applies only to double-pole filter.
1742 The default is 0.707q and gives a Butterworth response.
1747 Mix channels with specific gain levels. The filter accepts the output
1748 channel layout followed by a set of channels definitions.
1750 This filter is also designed to remap efficiently the channels of an audio
1753 The filter accepts parameters of the form:
1754 "@var{l}:@var{outdef}:@var{outdef}:..."
1758 output channel layout or number of channels
1761 output channel specification, of the form:
1762 "@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
1765 output channel to define, either a channel name (FL, FR, etc.) or a channel
1766 number (c0, c1, etc.)
1769 multiplicative coefficient for the channel, 1 leaving the volume unchanged
1772 input channel to use, see out_name for details; it is not possible to mix
1773 named and numbered input channels
1776 If the `=' in a channel specification is replaced by `<', then the gains for
1777 that specification will be renormalized so that the total is 1, thus
1778 avoiding clipping noise.
1780 @subsection Mixing examples
1782 For example, if you want to down-mix from stereo to mono, but with a bigger
1783 factor for the left channel:
1785 pan=1:c0=0.9*c0+0.1*c1
1788 A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
1789 7-channels surround:
1791 pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
1794 Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
1795 that should be preferred (see "-ac" option) unless you have very specific
1798 @subsection Remapping examples
1800 The channel remapping will be effective if, and only if:
1803 @item gain coefficients are zeroes or ones,
1804 @item only one input per channel output,
1807 If all these conditions are satisfied, the filter will notify the user ("Pure
1808 channel mapping detected"), and use an optimized and lossless method to do the
1811 For example, if you have a 5.1 source and want a stereo audio stream by
1812 dropping the extra channels:
1814 pan="stereo: c0=FL : c1=FR"
1817 Given the same source, you can also switch front left and front right channels
1818 and keep the input channel layout:
1820 pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
1823 If the input is a stereo audio stream, you can mute the front left channel (and
1824 still keep the stereo channel layout) with:
1829 Still with a stereo audio stream input, you can copy the right channel in both
1830 front left and right:
1832 pan="stereo: c0=FR : c1=FR"
1837 ReplayGain scanner filter. This filter takes an audio stream as an input and
1838 outputs it unchanged.
1839 At end of filtering it displays @code{track_gain} and @code{track_peak}.
1843 Convert the audio sample format, sample rate and channel layout. It is
1844 not meant to be used directly.
1846 @section silencedetect
1848 Detect silence in an audio stream.
1850 This filter logs a message when it detects that the input audio volume is less
1851 or equal to a noise tolerance value for a duration greater or equal to the
1852 minimum detected noise duration.
1854 The printed times and duration are expressed in seconds.
1856 The filter accepts the following options:
1860 Set silence duration until notification (default is 2 seconds).
1863 Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
1864 specified value) or amplitude ratio. Default is -60dB, or 0.001.
1867 @subsection Examples
1871 Detect 5 seconds of silence with -50dB noise tolerance:
1873 silencedetect=n=-50dB:d=5
1877 Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
1878 tolerance in @file{silence.mp3}:
1880 ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001 -f null -
1886 Boost or cut treble (upper) frequencies of the audio using a two-pole
1887 shelving filter with a response similar to that of a standard
1888 hi-fi's tone-controls. This is also known as shelving equalisation (EQ).
1890 The filter accepts the following options:
1894 Give the gain at whichever is the lower of ~22 kHz and the
1895 Nyquist frequency. Its useful range is about -20 (for a large cut)
1896 to +20 (for a large boost). Beware of clipping when using a positive gain.
1899 Set the filter's central frequency and so can be used
1900 to extend or reduce the frequency range to be boosted or cut.
1901 The default value is @code{3000} Hz.
1904 Set method to specify band-width of filter.
1917 Determine how steep is the filter's shelf transition.
1922 Adjust the input audio volume.
1924 It accepts the following parameters:
1928 Set audio volume expression.
1930 Output values are clipped to the maximum value.
1932 The output audio volume is given by the relation:
1934 @var{output_volume} = @var{volume} * @var{input_volume}
1937 The default value for @var{volume} is "1.0".
1940 This parameter represents the mathematical precision.
1942 It determines which input sample formats will be allowed, which affects the
1943 precision of the volume scaling.
1947 8-bit fixed-point; this limits input sample format to U8, S16, and S32.
1949 32-bit floating-point; this limits input sample format to FLT. (default)
1951 64-bit floating-point; this limits input sample format to DBL.
1955 Choose the behaviour on encountering ReplayGain side data in input frames.
1959 Remove ReplayGain side data, ignoring its contents (the default).
1962 Ignore ReplayGain side data, but leave it in the frame.
1965 Prefer the track gain, if present.
1968 Prefer the album gain, if present.
1971 @item replaygain_preamp
1972 Pre-amplification gain in dB to apply to the selected replaygain gain.
1974 Default value for @var{replaygain_preamp} is 0.0.
1977 Set when the volume expression is evaluated.
1979 It accepts the following values:
1982 only evaluate expression once during the filter initialization, or
1983 when the @samp{volume} command is sent
1986 evaluate expression for each incoming frame
1989 Default value is @samp{once}.
1992 The volume expression can contain the following parameters.
1996 frame number (starting at zero)
1999 @item nb_consumed_samples
2000 number of samples consumed by the filter
2002 number of samples in the current frame
2004 original frame position in the file
2010 PTS at start of stream
2012 time at start of stream
2018 last set volume value
2021 Note that when @option{eval} is set to @samp{once} only the
2022 @var{sample_rate} and @var{tb} variables are available, all other
2023 variables will evaluate to NAN.
2025 @subsection Commands
2027 This filter supports the following commands:
2030 Modify the volume expression.
2031 The command accepts the same syntax of the corresponding option.
2033 If the specified expression is not valid, it is kept at its current
2035 @item replaygain_noclip
2036 Prevent clipping by limiting the gain applied.
2038 Default value for @var{replaygain_noclip} is 1.
2042 @subsection Examples
2046 Halve the input audio volume:
2050 volume=volume=-6.0206dB
2053 In all the above example the named key for @option{volume} can be
2054 omitted, for example like in:
2060 Increase input audio power by 6 decibels using fixed-point precision:
2062 volume=volume=6dB:precision=fixed
2066 Fade volume after time 10 with an annihilation period of 5 seconds:
2068 volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
2072 @section volumedetect
2074 Detect the volume of the input video.
2076 The filter has no parameters. The input is not modified. Statistics about
2077 the volume will be printed in the log when the input stream end is reached.
2079 In particular it will show the mean volume (root mean square), maximum
2080 volume (on a per-sample basis), and the beginning of a histogram of the
2081 registered volume values (from the maximum value to a cumulated 1/1000 of
2084 All volumes are in decibels relative to the maximum PCM value.
2086 @subsection Examples
2088 Here is an excerpt of the output:
2090 [Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB
2091 [Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB
2092 [Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6
2093 [Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62
2094 [Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286
2095 [Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042
2096 [Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551
2097 [Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609
2098 [Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409
2104 The mean square energy is approximately -27 dB, or 10^-2.7.
2106 The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB.
2108 There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc.
2111 In other words, raising the volume by +4 dB does not cause any clipping,
2112 raising it by +5 dB causes clipping for 6 samples, etc.
2114 @c man end AUDIO FILTERS
2116 @chapter Audio Sources
2117 @c man begin AUDIO SOURCES
2119 Below is a description of the currently available audio sources.
2123 Buffer audio frames, and make them available to the filter chain.
2125 This source is mainly intended for a programmatic use, in particular
2126 through the interface defined in @file{libavfilter/asrc_abuffer.h}.
2128 It accepts the following parameters:
2132 The timebase which will be used for timestamps of submitted frames. It must be
2133 either a floating-point number or in @var{numerator}/@var{denominator} form.
2136 The sample rate of the incoming audio buffers.
2139 The sample format of the incoming audio buffers.
2140 Either a sample format name or its corresponging integer representation from
2141 the enum AVSampleFormat in @file{libavutil/samplefmt.h}
2143 @item channel_layout
2144 The channel layout of the incoming audio buffers.
2145 Either a channel layout name from channel_layout_map in
2146 @file{libavutil/channel_layout.c} or its corresponding integer representation
2147 from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h}
2150 The number of channels of the incoming audio buffers.
2151 If both @var{channels} and @var{channel_layout} are specified, then they
2156 @subsection Examples
2159 abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo
2162 will instruct the source to accept planar 16bit signed stereo at 44100Hz.
2163 Since the sample format with name "s16p" corresponds to the number
2164 6 and the "stereo" channel layout corresponds to the value 0x3, this is
2167 abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3
2172 Generate an audio signal specified by an expression.
2174 This source accepts in input one or more expressions (one for each
2175 channel), which are evaluated and used to generate a corresponding
2178 This source accepts the following options:
2182 Set the '|'-separated expressions list for each separate channel. In case the
2183 @option{channel_layout} option is not specified, the selected channel layout
2184 depends on the number of provided expressions. Otherwise the last
2185 specified expression is applied to the remaining output channels.
2187 @item channel_layout, c
2188 Set the channel layout. The number of channels in the specified layout
2189 must be equal to the number of specified expressions.
2192 Set the minimum duration of the sourced audio. See the function
2193 @code{av_parse_time()} for the accepted format.
2194 Note that the resulting duration may be greater than the specified
2195 duration, as the generated audio is always cut at the end of a
2198 If not specified, or the expressed duration is negative, the audio is
2199 supposed to be generated forever.
2202 Set the number of samples per channel per each output frame,
2205 @item sample_rate, s
2206 Specify the sample rate, default to 44100.
2209 Each expression in @var{exprs} can contain the following constants:
2213 number of the evaluated sample, starting from 0
2216 time of the evaluated sample expressed in seconds, starting from 0
2223 @subsection Examples
2233 Generate a sin signal with frequency of 440 Hz, set sample rate to
2236 aevalsrc="sin(440*2*PI*t):s=8000"
2240 Generate a two channels signal, specify the channel layout (Front
2241 Center + Back Center) explicitly:
2243 aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"
2247 Generate white noise:
2249 aevalsrc="-2+random(0)"
2253 Generate an amplitude modulated signal:
2255 aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
2259 Generate 2.5 Hz binaural beats on a 360 Hz carrier:
2261 aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"
2268 The null audio source, return unprocessed audio frames. It is mainly useful
2269 as a template and to be employed in analysis / debugging tools, or as
2270 the source for filters which ignore the input data (for example the sox
2273 This source accepts the following options:
2277 @item channel_layout, cl
2279 Specifies the channel layout, and can be either an integer or a string
2280 representing a channel layout. The default value of @var{channel_layout}
2283 Check the channel_layout_map definition in
2284 @file{libavutil/channel_layout.c} for the mapping between strings and
2285 channel layout values.
2287 @item sample_rate, r
2288 Specifies the sample rate, and defaults to 44100.
2291 Set the number of samples per requested frames.
2295 @subsection Examples
2299 Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
2301 anullsrc=r=48000:cl=4
2305 Do the same operation with a more obvious syntax:
2307 anullsrc=r=48000:cl=mono
2311 All the parameters need to be explicitly defined.
2315 Synthesize a voice utterance using the libflite library.
2317 To enable compilation of this filter you need to configure FFmpeg with
2318 @code{--enable-libflite}.
2320 Note that the flite library is not thread-safe.
2322 The filter accepts the following options:
2327 If set to 1, list the names of the available voices and exit
2328 immediately. Default value is 0.
2331 Set the maximum number of samples per frame. Default value is 512.
2334 Set the filename containing the text to speak.
2337 Set the text to speak.
2340 Set the voice to use for the speech synthesis. Default value is
2341 @code{kal}. See also the @var{list_voices} option.
2344 @subsection Examples
2348 Read from file @file{speech.txt}, and synthetize the text using the
2349 standard flite voice:
2351 flite=textfile=speech.txt
2355 Read the specified text selecting the @code{slt} voice:
2357 flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2361 Input text to ffmpeg:
2363 ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
2367 Make @file{ffplay} speak the specified text, using @code{flite} and
2368 the @code{lavfi} device:
2370 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
2374 For more information about libflite, check:
2375 @url{http://www.speech.cs.cmu.edu/flite/}
2379 Generate an audio signal made of a sine wave with amplitude 1/8.
2381 The audio signal is bit-exact.
2383 The filter accepts the following options:
2388 Set the carrier frequency. Default is 440 Hz.
2390 @item beep_factor, b
2391 Enable a periodic beep every second with frequency @var{beep_factor} times
2392 the carrier frequency. Default is 0, meaning the beep is disabled.
2394 @item sample_rate, r
2395 Specify the sample rate, default is 44100.
2398 Specify the duration of the generated audio stream.
2400 @item samples_per_frame
2401 Set the number of samples per output frame, default is 1024.
2404 @subsection Examples
2409 Generate a simple 440 Hz sine wave:
2415 Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds:
2419 sine=frequency=220:beep_factor=4:duration=5
2424 @c man end AUDIO SOURCES
2426 @chapter Audio Sinks
2427 @c man begin AUDIO SINKS
2429 Below is a description of the currently available audio sinks.
2431 @section abuffersink
2433 Buffer audio frames, and make them available to the end of filter chain.
2435 This sink is mainly intended for programmatic use, in particular
2436 through the interface defined in @file{libavfilter/buffersink.h}
2437 or the options system.
2439 It accepts a pointer to an AVABufferSinkContext structure, which
2440 defines the incoming buffers' formats, to be passed as the opaque
2441 parameter to @code{avfilter_init_filter} for initialization.
2444 Null audio sink; do absolutely nothing with the input audio. It is
2445 mainly useful as a template and for use in analysis / debugging
2448 @c man end AUDIO SINKS
2450 @chapter Video Filters
2451 @c man begin VIDEO FILTERS
2453 When you configure your FFmpeg build, you can disable any of the
2454 existing filters using @code{--disable-filters}.
2455 The configure output will show the video filters included in your
2458 Below is a description of the currently available video filters.
2460 @section alphaextract
2462 Extract the alpha component from the input as a grayscale video. This
2463 is especially useful with the @var{alphamerge} filter.
2467 Add or replace the alpha component of the primary input with the
2468 grayscale value of a second input. This is intended for use with
2469 @var{alphaextract} to allow the transmission or storage of frame
2470 sequences that have alpha in a format that doesn't support an alpha
2473 For example, to reconstruct full frames from a normal YUV-encoded video
2474 and a separate video created with @var{alphaextract}, you might use:
2476 movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]
2479 Since this filter is designed for reconstruction, it operates on frame
2480 sequences without considering timestamps, and terminates when either
2481 input reaches end of stream. This will cause problems if your encoding
2482 pipeline drops frames. If you're trying to apply an image as an
2483 overlay to a video stream, consider the @var{overlay} filter instead.
2487 Same as the @ref{subtitles} filter, except that it doesn't require libavcodec
2488 and libavformat to work. On the other hand, it is limited to ASS (Advanced
2489 Substation Alpha) subtitles files.
2493 Compute the bounding box for the non-black pixels in the input frame
2496 This filter computes the bounding box containing all the pixels with a
2497 luminance value greater than the minimum allowed value.
2498 The parameters describing the bounding box are printed on the filter
2501 The filter accepts the following option:
2505 Set the minimal luminance value. Default is @code{16}.
2508 @section blackdetect
2510 Detect video intervals that are (almost) completely black. Can be
2511 useful to detect chapter transitions, commercials, or invalid
2512 recordings. Output lines contains the time for the start, end and
2513 duration of the detected black interval expressed in seconds.
2515 In order to display the output lines, you need to set the loglevel at
2516 least to the AV_LOG_INFO value.
2518 The filter accepts the following options:
2521 @item black_min_duration, d
2522 Set the minimum detected black duration expressed in seconds. It must
2523 be a non-negative floating point number.
2525 Default value is 2.0.
2527 @item picture_black_ratio_th, pic_th
2528 Set the threshold for considering a picture "black".
2529 Express the minimum value for the ratio:
2531 @var{nb_black_pixels} / @var{nb_pixels}
2534 for which a picture is considered black.
2535 Default value is 0.98.
2537 @item pixel_black_th, pix_th
2538 Set the threshold for considering a pixel "black".
2540 The threshold expresses the maximum pixel luminance value for which a
2541 pixel is considered "black". The provided value is scaled according to
2542 the following equation:
2544 @var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
2547 @var{luminance_range_size} and @var{luminance_minimum_value} depend on
2548 the input video format, the range is [0-255] for YUV full-range
2549 formats and [16-235] for YUV non full-range formats.
2551 Default value is 0.10.
2554 The following example sets the maximum pixel threshold to the minimum
2555 value, and detects only black intervals of 2 or more seconds:
2557 blackdetect=d=2:pix_th=0.00
2562 Detect frames that are (almost) completely black. Can be useful to
2563 detect chapter transitions or commercials. Output lines consist of
2564 the frame number of the detected frame, the percentage of blackness,
2565 the position in the file if known or -1 and the timestamp in seconds.
2567 In order to display the output lines, you need to set the loglevel at
2568 least to the AV_LOG_INFO value.
2570 It accepts the following parameters:
2575 The percentage of the pixels that have to be below the threshold; it defaults to
2578 @item threshold, thresh
2579 The threshold below which a pixel value is considered black; it defaults to
2586 Blend two video frames into each other.
2588 It takes two input streams and outputs one stream, the first input is the
2589 "top" layer and second input is "bottom" layer.
2590 Output terminates when shortest input terminates.
2592 A description of the accepted options follows.
2600 Set blend mode for specific pixel component or all pixel components in case
2601 of @var{all_mode}. Default value is @code{normal}.
2603 Available values for component modes are:
2636 Set blend opacity for specific pixel component or all pixel components in case
2637 of @var{all_opacity}. Only used in combination with pixel component blend modes.
2644 Set blend expression for specific pixel component or all pixel components in case
2645 of @var{all_expr}. Note that related mode options will be ignored if those are set.
2647 The expressions can use the following variables:
2651 The sequential number of the filtered frame, starting from @code{0}.
2655 the coordinates of the current sample
2659 the width and height of currently filtered plane
2663 Width and height scale depending on the currently filtered plane. It is the
2664 ratio between the corresponding luma plane number of pixels and the current
2665 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
2666 @code{0.5,0.5} for chroma planes.
2669 Time of the current frame, expressed in seconds.
2672 Value of pixel component at current location for first video frame (top layer).
2675 Value of pixel component at current location for second video frame (bottom layer).
2679 Force termination when the shortest input terminates. Default is @code{0}.
2681 Continue applying the last bottom frame after the end of the stream. A value of
2682 @code{0} disable the filter after the last frame of the bottom layer is reached.
2683 Default is @code{1}.
2686 @subsection Examples
2690 Apply transition from bottom layer to top layer in first 10 seconds:
2692 blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'
2696 Apply 1x1 checkerboard effect:
2698 blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'
2702 Apply uncover left effect:
2704 blend=all_expr='if(gte(N*SW+X,W),A,B)'
2708 Apply uncover down effect:
2710 blend=all_expr='if(gte(Y-N*SH,0),A,B)'
2714 Apply uncover up-left effect:
2716 blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'
2722 Apply a boxblur algorithm to the input video.
2724 It accepts the following parameters:
2728 @item luma_radius, lr
2729 @item luma_power, lp
2730 @item chroma_radius, cr
2731 @item chroma_power, cp
2732 @item alpha_radius, ar
2733 @item alpha_power, ap
2737 A description of the accepted options follows.
2740 @item luma_radius, lr
2741 @item chroma_radius, cr
2742 @item alpha_radius, ar
2743 Set an expression for the box radius in pixels used for blurring the
2744 corresponding input plane.
2746 The radius value must be a non-negative number, and must not be
2747 greater than the value of the expression @code{min(w,h)/2} for the
2748 luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
2751 Default value for @option{luma_radius} is "2". If not specified,
2752 @option{chroma_radius} and @option{alpha_radius} default to the
2753 corresponding value set for @option{luma_radius}.
2755 The expressions can contain the following constants:
2759 The input width and height in pixels.
2763 The input chroma image width and height in pixels.
2767 The horizontal and vertical chroma subsample values. For example, for the
2768 pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
2771 @item luma_power, lp
2772 @item chroma_power, cp
2773 @item alpha_power, ap
2774 Specify how many times the boxblur filter is applied to the
2775 corresponding plane.
2777 Default value for @option{luma_power} is 2. If not specified,
2778 @option{chroma_power} and @option{alpha_power} default to the
2779 corresponding value set for @option{luma_power}.
2781 A value of 0 will disable the effect.
2784 @subsection Examples
2788 Apply a boxblur filter with the luma, chroma, and alpha radii
2791 boxblur=luma_radius=2:luma_power=1
2796 Set the luma radius to 2, and alpha and chroma radius to 0:
2798 boxblur=2:1:cr=0:ar=0
2802 Set the luma and chroma radii to a fraction of the video dimension:
2804 boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1
2808 @section colorbalance
2809 Modify intensity of primary colors (red, green and blue) of input frames.
2811 The filter allows an input frame to be adjusted in the shadows, midtones or highlights
2812 regions for the red-cyan, green-magenta or blue-yellow balance.
2814 A positive adjustment value shifts the balance towards the primary color, a negative
2815 value towards the complementary color.
2817 The filter accepts the following options:
2823 Adjust red, green and blue shadows (darkest pixels).
2828 Adjust red, green and blue midtones (medium pixels).
2833 Adjust red, green and blue highlights (brightest pixels).
2835 Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}.
2838 @subsection Examples
2842 Add red color cast to shadows:
2848 @section colorchannelmixer
2850 Adjust video input frames by re-mixing color channels.
2852 This filter modifies a color channel by adding the values associated to
2853 the other channels of the same pixels. For example if the value to
2854 modify is red, the output value will be:
2856 @var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra}
2859 The filter accepts the following options:
2866 Adjust contribution of input red, green, blue and alpha channels for output red channel.
2867 Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}.
2873 Adjust contribution of input red, green, blue and alpha channels for output green channel.
2874 Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}.
2880 Adjust contribution of input red, green, blue and alpha channels for output blue channel.
2881 Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}.
2887 Adjust contribution of input red, green, blue and alpha channels for output alpha channel.
2888 Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}.
2890 Allowed ranges for options are @code{[-2.0, 2.0]}.
2893 @subsection Examples
2897 Convert source to grayscale:
2899 colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3
2902 Simulate sepia tones:
2904 colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131
2908 @section colormatrix
2910 Convert color matrix.
2912 The filter accepts the following options:
2917 Specify the source and destination color matrix. Both values must be
2920 The accepted values are:
2936 For example to convert from BT.601 to SMPTE-240M, use the command:
2938 colormatrix=bt601:smpte240m
2943 Copy the input source unchanged to the output. This is mainly useful for
2948 Crop the input video to given dimensions.
2950 It accepts the following parameters:
2954 The width of the output video. It defaults to @code{iw}.
2955 This expression is evaluated only once during the filter
2959 The height of the output video. It defaults to @code{ih}.
2960 This expression is evaluated only once during the filter
2964 The horizontal position, in the input video, of the left edge of the output
2965 video. It defaults to @code{(in_w-out_w)/2}.
2966 This expression is evaluated per-frame.
2969 The vertical position, in the input video, of the top edge of the output video.
2970 It defaults to @code{(in_h-out_h)/2}.
2971 This expression is evaluated per-frame.
2974 If set to 1 will force the output display aspect ratio
2975 to be the same of the input, by changing the output sample aspect
2976 ratio. It defaults to 0.
2979 The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
2980 expressions containing the following constants:
2985 The computed values for @var{x} and @var{y}. They are evaluated for
2990 The input width and height.
2994 These are the same as @var{in_w} and @var{in_h}.
2998 The output (cropped) width and height.
3002 These are the same as @var{out_w} and @var{out_h}.
3005 same as @var{iw} / @var{ih}
3008 input sample aspect ratio
3011 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
3015 horizontal and vertical chroma subsample values. For example for the
3016 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3019 The number of the input frame, starting from 0.
3022 the position in the file of the input frame, NAN if unknown
3025 The timestamp expressed in seconds. It's NAN if the input timestamp is unknown.
3029 The expression for @var{out_w} may depend on the value of @var{out_h},
3030 and the expression for @var{out_h} may depend on @var{out_w}, but they
3031 cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
3032 evaluated after @var{out_w} and @var{out_h}.
3034 The @var{x} and @var{y} parameters specify the expressions for the
3035 position of the top-left corner of the output (non-cropped) area. They
3036 are evaluated for each frame. If the evaluated value is not valid, it
3037 is approximated to the nearest valid value.
3039 The expression for @var{x} may depend on @var{y}, and the expression
3040 for @var{y} may depend on @var{x}.
3042 @subsection Examples
3046 Crop area with size 100x100 at position (12,34).
3051 Using named options, the example above becomes:
3053 crop=w=100:h=100:x=12:y=34
3057 Crop the central input area with size 100x100:
3063 Crop the central input area with size 2/3 of the input video:
3065 crop=2/3*in_w:2/3*in_h
3069 Crop the input video central square:
3076 Delimit the rectangle with the top-left corner placed at position
3077 100:100 and the right-bottom corner corresponding to the right-bottom
3078 corner of the input image.
3080 crop=in_w-100:in_h-100:100:100
3084 Crop 10 pixels from the left and right borders, and 20 pixels from
3085 the top and bottom borders
3087 crop=in_w-2*10:in_h-2*20
3091 Keep only the bottom right quarter of the input image:
3093 crop=in_w/2:in_h/2:in_w/2:in_h/2
3097 Crop height for getting Greek harmony:
3099 crop=in_w:1/PHI*in_w
3103 Appply trembling effect:
3105 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)
3109 Apply erratic camera effect depending on timestamp:
3111 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)"
3115 Set x depending on the value of y:
3117 crop=in_w/2:in_h/2:y:10+10*sin(n/10)
3123 Auto-detect the crop size.
3125 It calculates the necessary cropping parameters and prints the
3126 recommended parameters via the logging system. The detected dimensions
3127 correspond to the non-black area of the input video.
3129 It accepts the following parameters:
3134 Set higher black value threshold, which can be optionally specified
3135 from nothing (0) to everything (255). An intensity value greater
3136 to the set value is considered non-black. It defaults to 24.
3139 The value which the width/height should be divisible by. It defaults to
3140 16. The offset is automatically adjusted to center the video. Use 2 to
3141 get only even dimensions (needed for 4:2:2 video). 16 is best when
3142 encoding to most video codecs.
3144 @item reset_count, reset
3145 Set the counter that determines after how many frames cropdetect will
3146 reset the previously detected largest video area and start over to
3147 detect the current optimal crop area. Default value is 0.
3149 This can be useful when channel logos distort the video area. 0
3150 indicates 'never reset', and returns the largest area encountered during
3157 Apply color adjustments using curves.
3159 This filter is similar to the Adobe Photoshop and GIMP curves tools. Each
3160 component (red, green and blue) has its values defined by @var{N} key points
3161 tied from each other using a smooth curve. The x-axis represents the pixel
3162 values from the input frame, and the y-axis the new pixel values to be set for
3165 By default, a component curve is defined by the two points @var{(0;0)} and
3166 @var{(1;1)}. This creates a straight line where each original pixel value is
3167 "adjusted" to its own value, which means no change to the image.
3169 The filter allows you to redefine these two points and add some more. A new
3170 curve (using a natural cubic spline interpolation) will be define to pass
3171 smoothly through all these new coordinates. The new defined points needs to be
3172 strictly increasing over the x-axis, and their @var{x} and @var{y} values must
3173 be in the @var{[0;1]} interval. If the computed curves happened to go outside
3174 the vector spaces, the values will be clipped accordingly.
3176 If there is no key point defined in @code{x=0}, the filter will automatically
3177 insert a @var{(0;0)} point. In the same way, if there is no key point defined
3178 in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
3180 The filter accepts the following options:
3184 Select one of the available color presets. This option can be used in addition
3185 to the @option{r}, @option{g}, @option{b} parameters; in this case, the later
3186 options takes priority on the preset values.
3187 Available presets are:
3190 @item color_negative
3193 @item increase_contrast
3195 @item linear_contrast
3196 @item medium_contrast
3198 @item strong_contrast
3201 Default is @code{none}.
3203 Set the master key points. These points will define a second pass mapping. It
3204 is sometimes called a "luminance" or "value" mapping. It can be used with
3205 @option{r}, @option{g}, @option{b} or @option{all} since it acts like a
3206 post-processing LUT.
3208 Set the key points for the red component.
3210 Set the key points for the green component.
3212 Set the key points for the blue component.
3214 Set the key points for all components (not including master).
3215 Can be used in addition to the other key points component
3216 options. In this case, the unset component(s) will fallback on this
3217 @option{all} setting.
3219 Specify a Photoshop curves file (@code{.asv}) to import the settings from.
3222 To avoid some filtergraph syntax conflicts, each key points list need to be
3223 defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
3225 @subsection Examples
3229 Increase slightly the middle level of blue:
3231 curves=blue='0.5/0.58'
3237 curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
3239 Here we obtain the following coordinates for each components:
3242 @code{(0;0.11) (0.42;0.51) (1;0.95)}
3244 @code{(0;0) (0.50;0.48) (1;1)}
3246 @code{(0;0.22) (0.49;0.44) (1;0.80)}
3250 The previous example can also be achieved with the associated built-in preset:
3252 curves=preset=vintage
3262 Use a Photoshop preset and redefine the points of the green component:
3264 curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53'
3270 Denoise frames using 2D DCT (frequency domain filtering).
3272 This filter is not designed for real time.
3274 The filter accepts the following options:
3278 Set the noise sigma constant.
3280 This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT
3281 coefficient (absolute value) below this threshold with be dropped.
3283 If you need a more advanced filtering, see @option{expr}.
3285 Default is @code{0}.
3288 Set number overlapping pixels for each block. Since the filter can be slow, you
3289 may want to reduce this value, at the cost of a less effective filter and the
3290 risk of various artefacts.
3292 If the overlapping value doesn't allow to process the whole input width or
3293 height, a warning will be displayed and according borders won't be denoised.
3295 Default value is @var{blocksize}-1, which is the best possible setting.
3298 Set the coefficient factor expression.
3300 For each coefficient of a DCT block, this expression will be evaluated as a
3301 multiplier value for the coefficient.
3303 If this is option is set, the @option{sigma} option will be ignored.
3305 The absolute value of the coefficient can be accessed through the @var{c}
3309 Set the @var{blocksize} using the number of bits. @code{1<<@var{n}} defines the
3310 @var{blocksize}, which is the width and height of the processed blocks.
3312 The default value is @var{3} (8x8) and can be raised to @var{4} for a
3313 @var{blocksize} of 16x16. Note that changing this setting has huge consequences
3314 on the speed processing. Also, a larger block size does not necessarily means a
3318 @subsection Examples
3320 Apply a denoise with a @option{sigma} of @code{4.5}:
3325 The same operation can be achieved using the expression system:
3327 dctdnoiz=e='gte(c, 4.5*3)'
3330 Violent denoise using a block size of @code{16x16}:
3338 Drop duplicated frames at regular intervals.
3340 The filter accepts the following options:
3344 Set the number of frames from which one will be dropped. Setting this to
3345 @var{N} means one frame in every batch of @var{N} frames will be dropped.
3346 Default is @code{5}.
3349 Set the threshold for duplicate detection. If the difference metric for a frame
3350 is less than or equal to this value, then it is declared as duplicate. Default
3354 Set scene change threshold. Default is @code{15}.
3358 Set the size of the x and y-axis blocks used during metric calculations.
3359 Larger blocks give better noise suppression, but also give worse detection of
3360 small movements. Must be a power of two. Default is @code{32}.
3363 Mark main input as a pre-processed input and activate clean source input
3364 stream. This allows the input to be pre-processed with various filters to help
3365 the metrics calculation while keeping the frame selection lossless. When set to
3366 @code{1}, the first stream is for the pre-processed input, and the second
3367 stream is the clean source from where the kept frames are chosen. Default is
3371 Set whether or not chroma is considered in the metric calculations. Default is
3377 Remove judder produced by partially interlaced telecined content.
3379 Judder can be introduced, for instance, by @ref{pullup} filter. If the original
3380 source was partially telecined content then the output of @code{pullup,dejudder}
3381 will have a variable frame rate. May change the recorded frame rate of the
3382 container. Aside from that change, this filter will not affect constant frame
3385 The option available in this filter is:
3389 Specify the length of the window over which the judder repeats.
3391 Accepts any integer greater than 1. Useful values are:
3395 If the original was telecined from 24 to 30 fps (Film to NTSC).
3398 If the original was telecined from 25 to 30 fps (PAL to NTSC).
3401 If a mixture of the two.
3404 The default is @samp{4}.
3409 Suppress a TV station logo by a simple interpolation of the surrounding
3410 pixels. Just set a rectangle covering the logo and watch it disappear
3411 (and sometimes something even uglier appear - your mileage may vary).
3413 It accepts the following parameters:
3418 Specify the top left corner coordinates of the logo. They must be
3423 Specify the width and height of the logo to clear. They must be
3427 Specify the thickness of the fuzzy edge of the rectangle (added to
3428 @var{w} and @var{h}). The default value is 4.
3431 When set to 1, a green rectangle is drawn on the screen to simplify
3432 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
3433 The default value is 0.
3435 The rectangle is drawn on the outermost pixels which will be (partly)
3436 replaced with interpolated values. The values of the next pixels
3437 immediately outside this rectangle in each direction will be used to
3438 compute the interpolated pixel values inside the rectangle.
3442 @subsection Examples
3446 Set a rectangle covering the area with top left corner coordinates 0,0
3447 and size 100x77, and a band of size 10:
3449 delogo=x=0:y=0:w=100:h=77:band=10
3456 Attempt to fix small changes in horizontal and/or vertical shift. This
3457 filter helps remove camera shake from hand-holding a camera, bumping a
3458 tripod, moving on a vehicle, etc.
3460 The filter accepts the following options:
3468 Specify a rectangular area where to limit the search for motion
3470 If desired the search for motion vectors can be limited to a
3471 rectangular area of the frame defined by its top left corner, width
3472 and height. These parameters have the same meaning as the drawbox
3473 filter which can be used to visualise the position of the bounding
3476 This is useful when simultaneous movement of subjects within the frame
3477 might be confused for camera motion by the motion vector search.
3479 If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
3480 then the full frame is used. This allows later options to be set
3481 without specifying the bounding box for the motion vector search.
3483 Default - search the whole frame.
3487 Specify the maximum extent of movement in x and y directions in the
3488 range 0-64 pixels. Default 16.
3491 Specify how to generate pixels to fill blanks at the edge of the
3492 frame. Available values are:
3495 Fill zeroes at blank locations
3497 Original image at blank locations
3499 Extruded edge value at blank locations
3501 Mirrored edge at blank locations
3503 Default value is @samp{mirror}.
3506 Specify the blocksize to use for motion search. Range 4-128 pixels,
3510 Specify the contrast threshold for blocks. Only blocks with more than
3511 the specified contrast (difference between darkest and lightest
3512 pixels) will be considered. Range 1-255, default 125.
3515 Specify the search strategy. Available values are:
3518 Set exhaustive search
3520 Set less exhaustive search.
3522 Default value is @samp{exhaustive}.
3525 If set then a detailed log of the motion search is written to the
3529 If set to 1, specify using OpenCL capabilities, only available if
3530 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
3536 Draw a colored box on the input image.
3538 It accepts the following parameters:
3543 The expressions which specify the top left corner coordinates of the box. It defaults to 0.
3547 The expressions which specify the width and height of the box; if 0 they are interpreted as
3548 the input width and height. It defaults to 0.
3551 Specify the color of the box to write. For the general syntax of this option,
3552 check the "Color" section in the ffmpeg-utils manual. If the special
3553 value @code{invert} is used, the box edge color is the same as the
3554 video with inverted luma.
3557 The expression which sets the thickness of the box edge. Default value is @code{3}.
3559 See below for the list of accepted constants.
3562 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3563 following constants:
3567 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3571 horizontal and vertical chroma subsample values. For example for the
3572 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3576 The input width and height.
3579 The input sample aspect ratio.
3583 The x and y offset coordinates where the box is drawn.
3587 The width and height of the drawn box.
3590 The thickness of the drawn box.
3592 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3593 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3597 @subsection Examples
3601 Draw a black box around the edge of the input image:
3607 Draw a box with color red and an opacity of 50%:
3609 drawbox=10:20:200:60:red@@0.5
3612 The previous example can be specified as:
3614 drawbox=x=10:y=20:w=200:h=60:color=red@@0.5
3618 Fill the box with pink color:
3620 drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max
3624 Draw a 2-pixel red 2.40:1 mask:
3626 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
3632 Draw a grid on the input image.
3634 It accepts the following parameters:
3639 The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0.
3643 The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the
3644 input width and height, respectively, minus @code{thickness}, so image gets
3645 framed. Default to 0.
3648 Specify the color of the grid. For the general syntax of this option,
3649 check the "Color" section in the ffmpeg-utils manual. If the special
3650 value @code{invert} is used, the grid color is the same as the
3651 video with inverted luma.
3654 The expression which sets the thickness of the grid line. Default value is @code{1}.
3656 See below for the list of accepted constants.
3659 The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the
3660 following constants:
3664 The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}.
3668 horizontal and vertical chroma subsample values. For example for the
3669 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3673 The input grid cell width and height.
3676 The input sample aspect ratio.
3680 The x and y coordinates of some point of grid intersection (meant to configure offset).
3684 The width and height of the drawn cell.
3687 The thickness of the drawn cell.
3689 These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to
3690 each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}.
3694 @subsection Examples
3698 Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%:
3700 drawgrid=width=100:height=100:thickness=2:color=red@@0.5
3704 Draw a white 3x3 grid with an opacity of 50%:
3706 drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5
3713 Draw a text string or text from a specified file on top of a video, using the
3714 libfreetype library.
3716 To enable compilation of this filter, you need to configure FFmpeg with
3717 @code{--enable-libfreetype}.
3718 To enable default font fallback and the @var{font} option you need to
3719 configure FFmpeg with @code{--enable-libfontconfig}.
3720 To enable the @var{text_shaping} option, you need to configure FFmpeg with
3721 @code{--enable-libfribidi}.
3725 It accepts the following parameters:
3730 Used to draw a box around text using the background color.
3731 The value must be either 1 (enable) or 0 (disable).
3732 The default value of @var{box} is 0.
3735 The color to be used for drawing box around text. For the syntax of this
3736 option, check the "Color" section in the ffmpeg-utils manual.
3738 The default value of @var{boxcolor} is "white".
3741 Set the width of the border to be drawn around the text using @var{bordercolor}.
3742 The default value of @var{borderw} is 0.
3745 Set the color to be used for drawing border around text. For the syntax of this
3746 option, check the "Color" section in the ffmpeg-utils manual.
3748 The default value of @var{bordercolor} is "black".
3751 Select how the @var{text} is expanded. Can be either @code{none},
3752 @code{strftime} (deprecated) or
3753 @code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section
3757 If true, check and fix text coords to avoid clipping.
3760 The color to be used for drawing fonts. For the syntax of this option, check
3761 the "Color" section in the ffmpeg-utils manual.
3763 The default value of @var{fontcolor} is "black".
3765 @item fontcolor_expr
3766 String which is expanded the same way as @var{text} to obtain dynamic
3767 @var{fontcolor} value. By default this option has empty value and is not
3768 processed. When this option is set, it overrides @var{fontcolor} option.
3771 The font family to be used for drawing text. By default Sans.
3774 The font file to be used for drawing text. The path must be included.
3775 This parameter is mandatory if the fontconfig support is disabled.
3778 The font size to be used for drawing text.
3779 The default value of @var{fontsize} is 16.
3782 If set to 1, attempt to shape the text (for example, reverse the order of
3783 right-to-left text and join Arabic characters) before drawing it.
3784 Otherwise, just draw the text exactly as given.
3785 By default 1 (if supported).
3788 The flags to be used for loading the fonts.
3790 The flags map the corresponding flags supported by libfreetype, and are
3791 a combination of the following values:
3798 @item vertical_layout
3799 @item force_autohint
3802 @item ignore_global_advance_width
3804 @item ignore_transform
3810 Default value is "default".
3812 For more information consult the documentation for the FT_LOAD_*
3816 The color to be used for drawing a shadow behind the drawn text. For the
3817 syntax of this option, check the "Color" section in the ffmpeg-utils manual.
3819 The default value of @var{shadowcolor} is "black".
3823 The x and y offsets for the text shadow position with respect to the
3824 position of the text. They can be either positive or negative
3825 values. The default value for both is "0".
3828 The starting frame number for the n/frame_num variable. The default value
3832 The size in number of spaces to use for rendering the tab.
3836 Set the initial timecode representation in "hh:mm:ss[:;.]ff"
3837 format. It can be used with or without text parameter. @var{timecode_rate}
3838 option must be specified.
3840 @item timecode_rate, rate, r
3841 Set the timecode frame rate (timecode only).
3844 The text string to be drawn. The text must be a sequence of UTF-8
3846 This parameter is mandatory if no file is specified with the parameter
3850 A text file containing text to be drawn. The text must be a sequence
3851 of UTF-8 encoded characters.
3853 This parameter is mandatory if no text string is specified with the
3854 parameter @var{text}.
3856 If both @var{text} and @var{textfile} are specified, an error is thrown.
3859 If set to 1, the @var{textfile} will be reloaded before each frame.
3860 Be sure to update it atomically, or it may be read partially, or even fail.
3864 The expressions which specify the offsets where text will be drawn
3865 within the video frame. They are relative to the top/left border of the
3868 The default value of @var{x} and @var{y} is "0".
3870 See below for the list of accepted constants and functions.
3873 The parameters for @var{x} and @var{y} are expressions containing the
3874 following constants and functions:
3878 input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
3882 horizontal and vertical chroma subsample values. For example for the
3883 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
3886 the height of each text line
3894 @item max_glyph_a, ascent
3895 the maximum distance from the baseline to the highest/upper grid
3896 coordinate used to place a glyph outline point, for all the rendered
3898 It is a positive value, due to the grid's orientation with the Y axis
3901 @item max_glyph_d, descent
3902 the maximum distance from the baseline to the lowest grid coordinate
3903 used to place a glyph outline point, for all the rendered glyphs.
3904 This is a negative value, due to the grid's orientation, with the Y axis
3908 maximum glyph height, that is the maximum height for all the glyphs
3909 contained in the rendered text, it is equivalent to @var{ascent} -
3913 maximum glyph width, that is the maximum width for all the glyphs
3914 contained in the rendered text
3917 the number of input frame, starting from 0
3919 @item rand(min, max)
3920 return a random number included between @var{min} and @var{max}
3923 The input sample aspect ratio.
3926 timestamp expressed in seconds, NAN if the input timestamp is unknown
3929 the height of the rendered text
3932 the width of the rendered text
3936 the x and y offset coordinates where the text is drawn.
3938 These parameters allow the @var{x} and @var{y} expressions to refer
3939 each other, so you can for example specify @code{y=x/dar}.
3942 @anchor{drawtext_expansion}
3943 @subsection Text expansion
3945 If @option{expansion} is set to @code{strftime},
3946 the filter recognizes strftime() sequences in the provided text and
3947 expands them accordingly. Check the documentation of strftime(). This
3948 feature is deprecated.
3950 If @option{expansion} is set to @code{none}, the text is printed verbatim.
3952 If @option{expansion} is set to @code{normal} (which is the default),
3953 the following expansion mechanism is used.
3955 The backslash character '\', followed by any character, always expands to
3956 the second character.
3958 Sequence of the form @code{%@{...@}} are expanded. The text between the
3959 braces is a function name, possibly followed by arguments separated by ':'.
3960 If the arguments contain special characters or delimiters (':' or '@}'),
3961 they should be escaped.
3963 Note that they probably must also be escaped as the value for the
3964 @option{text} option in the filter argument string and as the filter
3965 argument in the filtergraph description, and possibly also for the shell,
3966 that makes up to four levels of escaping; using a text file avoids these
3969 The following functions are available:
3974 The expression evaluation result.
3976 It must take one argument specifying the expression to be evaluated,
3977 which accepts the same constants and functions as the @var{x} and
3978 @var{y} values. Note that not all constants should be used, for
3979 example the text size is not known when evaluating the expression, so
3980 the constants @var{text_w} and @var{text_h} will have an undefined
3983 @item expr_int_format, eif
3984 Evaluate the expression's value and output as formatted integer.
3986 First argument is expression to be evaluated, same as for @var{expr} function.
3987 Second argument specifies output format. Allowed values are 'x', 'X', 'd' and
3988 'u', they are treated exactly as in printf function.
3989 Third parameter is optional and sets the number of positions taken by output.
3990 Effectively this allows to add padding with zeros from the left.
3993 The time at which the filter is running, expressed in UTC.
3994 It can accept an argument: a strftime() format string.
3997 The time at which the filter is running, expressed in the local time zone.
3998 It can accept an argument: a strftime() format string.
4001 Frame metadata. It must take one argument specifying metadata key.
4004 The frame number, starting from 0.
4007 A 1 character description of the current picture type.
4010 The timestamp of the current frame.
4011 It can take up to two arguments.
4013 The first argument is the format of the timestamp; it defaults to @code{flt}
4014 for seconds as a decimal number with microsecond accuracy; @code{hms} stands
4015 for a formatted @var{[-]HH:MM:SS.mmm} timestamp with millisecond accuracy.
4017 The second argument is an offset added to the timestamp.
4021 @subsection Examples
4025 Draw "Test Text" with font FreeSerif, using the default values for the
4026 optional parameters.
4029 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
4033 Draw 'Test Text' with font FreeSerif of size 24 at position x=100
4034 and y=50 (counting from the top-left corner of the screen), text is
4035 yellow with a red box around it. Both the text and the box have an
4039 drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
4040 x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
4043 Note that the double quotes are not necessary if spaces are not used
4044 within the parameter list.
4047 Show the text at the center of the video frame:
4049 drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
4053 Show a text line sliding from right to left in the last row of the video
4054 frame. The file @file{LONG_LINE} is assumed to contain a single line
4057 drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
4061 Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
4063 drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
4067 Draw a single green letter "g", at the center of the input video.
4068 The glyph baseline is placed at half screen height.
4070 drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
4074 Show text for 1 second every 3 seconds:
4076 drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"
4080 Use fontconfig to set the font. Note that the colons need to be escaped.
4082 drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
4086 Print the date of a real-time encoding (see strftime(3)):
4088 drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}'
4092 Shwo text fading in and out (appearing/disappearing):
4095 DS=1.0 # display start
4096 DE=10.0 # display end
4097 FID=1.5 # fade in duration
4098 FOD=5 # fade out duration
4099 ffplay -f lavfi "color,drawtext=text=TEST:fontsize=50:fontfile=FreeSerif.ttf:fontcolor_expr=ff0000%@{eif\\\\: clip(255*(1*between(t\\, $DS + $FID\\, $DE - $FOD) + ((t - $DS)/$FID)*between(t\\, $DS\\, $DS + $FID) + (-(t - $DE)/$FOD)*between(t\\, $DE - $FOD\\, $DE) )\\, 0\\, 255) \\\\: x\\\\: 2 @}"
4104 For more information about libfreetype, check:
4105 @url{http://www.freetype.org/}.
4107 For more information about fontconfig, check:
4108 @url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
4110 For more information about libfribidi, check:
4111 @url{http://fribidi.org/}.
4115 Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
4117 The filter accepts the following options:
4122 Set low and high threshold values used by the Canny thresholding
4125 The high threshold selects the "strong" edge pixels, which are then
4126 connected through 8-connectivity with the "weak" edge pixels selected
4127 by the low threshold.
4129 @var{low} and @var{high} threshold values must be chosen in the range
4130 [0,1], and @var{low} should be lesser or equal to @var{high}.
4132 Default value for @var{low} is @code{20/255}, and default value for @var{high}
4136 Define the drawing mode.
4140 Draw white/gray wires on black background.
4143 Mix the colors to create a paint/cartoon effect.
4146 Default value is @var{wires}.
4149 @subsection Examples
4153 Standard edge detection with custom values for the hysteresis thresholding:
4155 edgedetect=low=0.1:high=0.4
4159 Painting effect without thresholding:
4161 edgedetect=mode=colormix:high=0
4165 @section extractplanes
4167 Extract color channel components from input video stream into
4168 separate grayscale video streams.
4170 The filter accepts the following option:
4174 Set plane(s) to extract.
4176 Available values for planes are:
4187 Choosing planes not available in the input will result in an error.
4188 That means you cannot select @code{r}, @code{g}, @code{b} planes
4189 with @code{y}, @code{u}, @code{v} planes at same time.
4192 @subsection Examples
4196 Extract luma, u and v color channel component from input video frame
4197 into 3 grayscale outputs:
4199 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
4205 Apply a posterize effect using the ELBG (Enhanced LBG) algorithm.
4207 For each input image, the filter will compute the optimal mapping from
4208 the input to the output given the codebook length, that is the number
4209 of distinct output colors.
4211 This filter accepts the following options.
4214 @item codebook_length, l
4215 Set codebook length. The value must be a positive integer, and
4216 represents the number of distinct output colors. Default value is 256.
4219 Set the maximum number of iterations to apply for computing the optimal
4220 mapping. The higher the value the better the result and the higher the
4221 computation time. Default value is 1.
4224 Set a random seed, must be an integer included between 0 and
4225 UINT32_MAX. If not specified, or if explicitly set to -1, the filter
4226 will try to use a good random seed on a best effort basis.
4231 Apply a fade-in/out effect to the input video.
4233 It accepts the following parameters:
4237 The effect type can be either "in" for a fade-in, or "out" for a fade-out
4239 Default is @code{in}.
4241 @item start_frame, s
4242 Specify the number of the frame to start applying the fade
4243 effect at. Default is 0.
4246 The number of frames that the fade effect lasts. At the end of the
4247 fade-in effect, the output video will have the same intensity as the input video.
4248 At the end of the fade-out transition, the output video will be filled with the
4249 selected @option{color}.
4253 If set to 1, fade only alpha channel, if one exists on the input.
4256 @item start_time, st
4257 Specify the timestamp (in seconds) of the frame to start to apply the fade
4258 effect. If both start_frame and start_time are specified, the fade will start at
4259 whichever comes last. Default is 0.
4262 The number of seconds for which the fade effect has to last. At the end of the
4263 fade-in effect the output video will have the same intensity as the input video,
4264 at the end of the fade-out transition the output video will be filled with the
4265 selected @option{color}.
4266 If both duration and nb_frames are specified, duration is used. Default is 0.
4269 Specify the color of the fade. Default is "black".
4272 @subsection Examples
4276 Fade in the first 30 frames of video:
4281 The command above is equivalent to:
4287 Fade out the last 45 frames of a 200-frame video:
4290 fade=type=out:start_frame=155:nb_frames=45
4294 Fade in the first 25 frames and fade out the last 25 frames of a 1000-frame video:
4296 fade=in:0:25, fade=out:975:25
4300 Make the first 5 frames yellow, then fade in from frame 5-24:
4302 fade=in:5:20:color=yellow
4306 Fade in alpha over first 25 frames of video:
4308 fade=in:0:25:alpha=1
4312 Make the first 5.5 seconds black, then fade in for 0.5 seconds:
4314 fade=t=in:st=5.5:d=0.5
4321 Extract a single field from an interlaced image using stride
4322 arithmetic to avoid wasting CPU time. The output frames are marked as
4325 The filter accepts the following options:
4329 Specify whether to extract the top (if the value is @code{0} or
4330 @code{top}) or the bottom field (if the value is @code{1} or
4336 Field matching filter for inverse telecine. It is meant to reconstruct the
4337 progressive frames from a telecined stream. The filter does not drop duplicated
4338 frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be
4339 followed by a decimation filter such as @ref{decimate} in the filtergraph.
4341 The separation of the field matching and the decimation is notably motivated by
4342 the possibility of inserting a de-interlacing filter fallback between the two.
4343 If the source has mixed telecined and real interlaced content,
4344 @code{fieldmatch} will not be able to match fields for the interlaced parts.
4345 But these remaining combed frames will be marked as interlaced, and thus can be
4346 de-interlaced by a later filter such as @ref{yadif} before decimation.
4348 In addition to the various configuration options, @code{fieldmatch} can take an
4349 optional second stream, activated through the @option{ppsrc} option. If
4350 enabled, the frames reconstruction will be based on the fields and frames from
4351 this second stream. This allows the first input to be pre-processed in order to
4352 help the various algorithms of the filter, while keeping the output lossless
4353 (assuming the fields are matched properly). Typically, a field-aware denoiser,
4354 or brightness/contrast adjustments can help.
4356 Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project)
4357 and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from
4358 which @code{fieldmatch} is based on. While the semantic and usage are very
4359 close, some behaviour and options names can differ.
4361 The filter accepts the following options:
4365 Specify the assumed field order of the input stream. Available values are:
4369 Auto detect parity (use FFmpeg's internal parity value).
4371 Assume bottom field first.
4373 Assume top field first.
4376 Note that it is sometimes recommended not to trust the parity announced by the
4379 Default value is @var{auto}.
4382 Set the matching mode or strategy to use. @option{pc} mode is the safest in the
4383 sense that it won't risk creating jerkiness due to duplicate frames when
4384 possible, but if there are bad edits or blended fields it will end up
4385 outputting combed frames when a good match might actually exist. On the other
4386 hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness,
4387 but will almost always find a good frame if there is one. The other values are
4388 all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking
4389 jerkiness and creating duplicate frames versus finding good matches in sections
4390 with bad edits, orphaned fields, blended fields, etc.
4392 More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section.
4394 Available values are:
4398 2-way matching (p/c)
4400 2-way matching, and trying 3rd match if still combed (p/c + n)
4402 2-way matching, and trying 3rd match (same order) if still combed (p/c + u)
4404 2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if
4405 still combed (p/c + n + u/b)
4407 3-way matching (p/c/n)
4409 3-way matching, and trying 4th/5th matches if all 3 of the original matches are
4410 detected as combed (p/c/n + u/b)
4413 The parenthesis at the end indicate the matches that would be used for that
4414 mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or
4417 In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is
4420 Default value is @var{pc_n}.
4423 Mark the main input stream as a pre-processed input, and enable the secondary
4424 input stream as the clean source to pick the fields from. See the filter
4425 introduction for more details. It is similar to the @option{clip2} feature from
4428 Default value is @code{0} (disabled).
4431 Set the field to match from. It is recommended to set this to the same value as
4432 @option{order} unless you experience matching failures with that setting. In
4433 certain circumstances changing the field that is used to match from can have a
4434 large impact on matching performance. Available values are:
4438 Automatic (same value as @option{order}).
4440 Match from the bottom field.
4442 Match from the top field.
4445 Default value is @var{auto}.
4448 Set whether or not chroma is included during the match comparisons. In most
4449 cases it is recommended to leave this enabled. You should set this to @code{0}
4450 only if your clip has bad chroma problems such as heavy rainbowing or other
4451 artifacts. Setting this to @code{0} could also be used to speed things up at
4452 the cost of some accuracy.
4454 Default value is @code{1}.
4458 These define an exclusion band which excludes the lines between @option{y0} and
4459 @option{y1} from being included in the field matching decision. An exclusion
4460 band can be used to ignore subtitles, a logo, or other things that may
4461 interfere with the matching. @option{y0} sets the starting scan line and
4462 @option{y1} sets the ending line; all lines in between @option{y0} and
4463 @option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting
4464 @option{y0} and @option{y1} to the same value will disable the feature.
4465 @option{y0} and @option{y1} defaults to @code{0}.
4468 Set the scene change detection threshold as a percentage of maximum change on
4469 the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change
4470 detection is only relevant in case @option{combmatch}=@var{sc}. The range for
4471 @option{scthresh} is @code{[0.0, 100.0]}.
4473 Default value is @code{12.0}.
4476 When @option{combatch} is not @var{none}, @code{fieldmatch} will take into
4477 account the combed scores of matches when deciding what match to use as the
4478 final match. Available values are:
4482 No final matching based on combed scores.
4484 Combed scores are only used when a scene change is detected.
4486 Use combed scores all the time.
4489 Default is @var{sc}.
4492 Force @code{fieldmatch} to calculate the combed metrics for certain matches and
4493 print them. This setting is known as @option{micout} in TFM/VFM vocabulary.
4494 Available values are:
4498 No forced calculation.
4500 Force p/c/n calculations.
4502 Force p/c/n/u/b calculations.
4505 Default value is @var{none}.
4508 This is the area combing threshold used for combed frame detection. This
4509 essentially controls how "strong" or "visible" combing must be to be detected.
4510 Larger values mean combing must be more visible and smaller values mean combing
4511 can be less visible or strong and still be detected. Valid settings are from
4512 @code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will
4513 be detected as combed). This is basically a pixel difference value. A good
4514 range is @code{[8, 12]}.
4516 Default value is @code{9}.
4519 Sets whether or not chroma is considered in the combed frame decision. Only
4520 disable this if your source has chroma problems (rainbowing, etc.) that are
4521 causing problems for the combed frame detection with chroma enabled. Actually,
4522 using @option{chroma}=@var{0} is usually more reliable, except for the case
4523 where there is chroma only combing in the source.
4525 Default value is @code{0}.
4529 Respectively set the x-axis and y-axis size of the window used during combed
4530 frame detection. This has to do with the size of the area in which
4531 @option{combpel} pixels are required to be detected as combed for a frame to be
4532 declared combed. See the @option{combpel} parameter description for more info.
4533 Possible values are any number that is a power of 2 starting at 4 and going up
4536 Default value is @code{16}.
4539 The number of combed pixels inside any of the @option{blocky} by
4540 @option{blockx} size blocks on the frame for the frame to be detected as
4541 combed. While @option{cthresh} controls how "visible" the combing must be, this
4542 setting controls "how much" combing there must be in any localized area (a
4543 window defined by the @option{blockx} and @option{blocky} settings) on the
4544 frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at
4545 which point no frames will ever be detected as combed). This setting is known
4546 as @option{MI} in TFM/VFM vocabulary.
4548 Default value is @code{80}.
4551 @anchor{p/c/n/u/b meaning}
4552 @subsection p/c/n/u/b meaning
4554 @subsubsection p/c/n
4556 We assume the following telecined stream:
4559 Top fields: 1 2 2 3 4
4560 Bottom fields: 1 2 3 4 4
4563 The numbers correspond to the progressive frame the fields relate to. Here, the
4564 first two frames are progressive, the 3rd and 4th are combed, and so on.
4566 When @code{fieldmatch} is configured to run a matching from bottom
4567 (@option{field}=@var{bottom}) this is how this input stream get transformed:
4572 B 1 2 3 4 4 <-- matching reference
4581 As a result of the field matching, we can see that some frames get duplicated.
4582 To perform a complete inverse telecine, you need to rely on a decimation filter
4583 after this operation. See for instance the @ref{decimate} filter.
4585 The same operation now matching from top fields (@option{field}=@var{top})
4590 T 1 2 2 3 4 <-- matching reference
4600 In these examples, we can see what @var{p}, @var{c} and @var{n} mean;
4601 basically, they refer to the frame and field of the opposite parity:
4604 @item @var{p} matches the field of the opposite parity in the previous frame
4605 @item @var{c} matches the field of the opposite parity in the current frame
4606 @item @var{n} matches the field of the opposite parity in the next frame
4611 The @var{u} and @var{b} matching are a bit special in the sense that they match
4612 from the opposite parity flag. In the following examples, we assume that we are
4613 currently matching the 2nd frame (Top:2, bottom:2). According to the match, a
4614 'x' is placed above and below each matched fields.
4616 With bottom matching (@option{field}=@var{bottom}):
4621 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4622 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4630 With top matching (@option{field}=@var{top}):
4635 Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2
4636 Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
4644 @subsection Examples
4646 Simple IVTC of a top field first telecined stream:
4648 fieldmatch=order=tff:combmatch=none, decimate
4651 Advanced IVTC, with fallback on @ref{yadif} for still combed frames:
4653 fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate
4658 Transform the field order of the input video.
4660 It accepts the following parameters:
4665 The output field order. Valid values are @var{tff} for top field first or @var{bff}
4666 for bottom field first.
4669 The default value is @samp{tff}.
4671 The transformation is done by shifting the picture content up or down
4672 by one line, and filling the remaining line with appropriate picture content.
4673 This method is consistent with most broadcast field order converters.
4675 If the input video is not flagged as being interlaced, or it is already
4676 flagged as being of the required output field order, then this filter does
4677 not alter the incoming video.
4679 It is very useful when converting to or from PAL DV material,
4680 which is bottom field first.
4684 ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
4689 Buffer input images and send them when they are requested.
4691 It is mainly useful when auto-inserted by the libavfilter
4694 It does not take parameters.
4699 Convert the input video to one of the specified pixel formats.
4700 Libavfilter will try to pick one that is suitable as input to
4703 It accepts the following parameters:
4707 A '|'-separated list of pixel format names, such as
4708 "pix_fmts=yuv420p|monow|rgb24".
4712 @subsection Examples
4716 Convert the input video to the @var{yuv420p} format
4718 format=pix_fmts=yuv420p
4721 Convert the input video to any of the formats in the list
4723 format=pix_fmts=yuv420p|yuv444p|yuv410p
4730 Convert the video to specified constant frame rate by duplicating or dropping
4731 frames as necessary.
4733 It accepts the following parameters:
4737 The desired output frame rate. The default is @code{25}.
4742 Possible values are:
4745 zero round towards 0
4749 round towards -infinity
4751 round towards +infinity
4755 The default is @code{near}.
4758 Assume the first PTS should be the given value, in seconds. This allows for
4759 padding/trimming at the start of stream. By default, no assumption is made
4760 about the first frame's expected PTS, so no padding or trimming is done.
4761 For example, this could be set to 0 to pad the beginning with duplicates of
4762 the first frame if a video stream starts after the audio stream or to trim any
4763 frames with a negative PTS.
4767 Alternatively, the options can be specified as a flat string:
4768 @var{fps}[:@var{round}].
4770 See also the @ref{setpts} filter.
4772 @subsection Examples
4776 A typical usage in order to set the fps to 25:
4782 Sets the fps to 24, using abbreviation and rounding method to round to nearest:
4784 fps=fps=film:round=near
4790 Pack two different video streams into a stereoscopic video, setting proper
4791 metadata on supported codecs. The two views should have the same size and
4792 framerate and processing will stop when the shorter video ends. Please note
4793 that you may conveniently adjust view properties with the @ref{scale} and
4796 It accepts the following parameters:
4800 The desired packing format. Supported values are:
4805 The views are next to each other (default).
4808 The views are on top of each other.
4811 The views are packed by line.
4814 The views are packed by column.
4817 The views are temporally interleaved.
4826 # Convert left and right views into a frame-sequential video
4827 ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT
4829 # Convert views into a side-by-side video with the same output resolution as the input
4830 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
4835 Select one frame every N-th frame.
4837 This filter accepts the following option:
4840 Select frame after every @code{step} frames.
4841 Allowed values are positive integers higher than 0. Default value is @code{1}.
4847 Apply a frei0r effect to the input video.
4849 To enable the compilation of this filter, you need to install the frei0r
4850 header and configure FFmpeg with @code{--enable-frei0r}.
4852 It accepts the following parameters:
4857 The name of the frei0r effect to load. If the environment variable
4858 @env{FREI0R_PATH} is defined, the frei0r effect is searched for in each of the
4859 directories specified by the colon-separated list in @env{FREIOR_PATH}.
4860 Otherwise, the standard frei0r paths are searched, in this order:
4861 @file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/},
4862 @file{/usr/lib/frei0r-1/}.
4865 A '|'-separated list of parameters to pass to the frei0r effect.
4869 A frei0r effect parameter can be a boolean (its value is either
4870 "y" or "n"), a double, a color (specified as
4871 @var{R}/@var{G}/@var{B}, where @var{R}, @var{G}, and @var{B} are floating point
4872 numbers between 0.0 and 1.0, inclusive) or by a color description specified in the "Color"
4873 section in the ffmpeg-utils manual), a position (specified as @var{X}/@var{Y}, where
4874 @var{X} and @var{Y} are floating point numbers) and/or a string.
4876 The number and types of parameters depend on the loaded effect. If an
4877 effect parameter is not specified, the default value is set.
4879 @subsection Examples
4883 Apply the distort0r effect, setting the first two double parameters:
4885 frei0r=filter_name=distort0r:filter_params=0.5|0.01
4889 Apply the colordistance effect, taking a color as the first parameter:
4891 frei0r=colordistance:0.2/0.3/0.4
4892 frei0r=colordistance:violet
4893 frei0r=colordistance:0x112233
4897 Apply the perspective effect, specifying the top left and top right image
4900 frei0r=perspective:0.2/0.2|0.8/0.2
4904 For more information, see
4905 @url{http://frei0r.dyne.org}
4909 The filter accepts the following options:
4913 Set the luminance expression.
4915 Set the chrominance blue expression.
4917 Set the chrominance red expression.
4919 Set the alpha expression.
4921 Set the red expression.
4923 Set the green expression.
4925 Set the blue expression.
4928 The colorspace is selected according to the specified options. If one
4929 of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr}
4930 options is specified, the filter will automatically select a YCbCr
4931 colorspace. If one of the @option{red_expr}, @option{green_expr}, or
4932 @option{blue_expr} options is specified, it will select an RGB
4935 If one of the chrominance expression is not defined, it falls back on the other
4936 one. If no alpha expression is specified it will evaluate to opaque value.
4937 If none of chrominance expressions are specified, they will evaluate
4938 to the luminance expression.
4940 The expressions can use the following variables and functions:
4944 The sequential number of the filtered frame, starting from @code{0}.
4948 The coordinates of the current sample.
4952 The width and height of the image.
4956 Width and height scale depending on the currently filtered plane. It is the
4957 ratio between the corresponding luma plane number of pixels and the current
4958 plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and
4959 @code{0.5,0.5} for chroma planes.
4962 Time of the current frame, expressed in seconds.
4965 Return the value of the pixel at location (@var{x},@var{y}) of the current
4969 Return the value of the pixel at location (@var{x},@var{y}) of the luminance
4973 Return the value of the pixel at location (@var{x},@var{y}) of the
4974 blue-difference chroma plane. Return 0 if there is no such plane.
4977 Return the value of the pixel at location (@var{x},@var{y}) of the
4978 red-difference chroma plane. Return 0 if there is no such plane.
4983 Return the value of the pixel at location (@var{x},@var{y}) of the
4984 red/green/blue component. Return 0 if there is no such component.
4987 Return the value of the pixel at location (@var{x},@var{y}) of the alpha
4988 plane. Return 0 if there is no such plane.
4991 For functions, if @var{x} and @var{y} are outside the area, the value will be
4992 automatically clipped to the closer edge.
4994 @subsection Examples
4998 Flip the image horizontally:
5004 Generate a bidimensional sine wave, with angle @code{PI/3} and a
5005 wavelength of 100 pixels:
5007 geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128
5011 Generate a fancy enigmatic moving light:
5013 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
5017 Generate a quick emboss effect:
5019 format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'
5023 Modify RGB components depending on pixel position:
5025 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
5031 Fix the banding artifacts that are sometimes introduced into nearly flat
5032 regions by truncation to 8bit color depth.
5033 Interpolate the gradients that should go where the bands are, and
5036 It is designed for playback only. Do not use it prior to
5037 lossy compression, because compression tends to lose the dither and
5038 bring back the bands.
5040 It accepts the following parameters:
5045 The maximum amount by which the filter will change any one pixel. This is also
5046 the threshold for detecting nearly flat regions. Acceptable values range from
5047 .51 to 64; the default value is 1.2. Out-of-range values will be clipped to the
5051 The neighborhood to fit the gradient to. A larger radius makes for smoother
5052 gradients, but also prevents the filter from modifying the pixels near detailed
5053 regions. Acceptable values are 8-32; the default value is 16. Out-of-range
5054 values will be clipped to the valid range.
5058 Alternatively, the options can be specified as a flat string:
5059 @var{strength}[:@var{radius}]
5061 @subsection Examples
5065 Apply the filter with a @code{3.5} strength and radius of @code{8}:
5071 Specify radius, omitting the strength (which will fall-back to the default
5082 Apply a Hald CLUT to a video stream.
5084 First input is the video stream to process, and second one is the Hald CLUT.
5085 The Hald CLUT input can be a simple picture or a complete video stream.
5087 The filter accepts the following options:
5091 Force termination when the shortest input terminates. Default is @code{0}.
5093 Continue applying the last CLUT after the end of the stream. A value of
5094 @code{0} disable the filter after the last frame of the CLUT is reached.
5095 Default is @code{1}.
5098 @code{haldclut} also has the same interpolation options as @ref{lut3d} (both
5099 filters share the same internals).
5101 More information about the Hald CLUT can be found on Eskil Steenberg's website
5102 (Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}.
5104 @subsection Workflow examples
5106 @subsubsection Hald CLUT video stream
5108 Generate an identity Hald CLUT stream altered with various effects:
5110 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
5113 Note: make sure you use a lossless codec.
5115 Then use it with @code{haldclut} to apply it on some random stream:
5117 ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv
5120 The Hald CLUT will be applied to the 10 first seconds (duration of
5121 @file{clut.nut}), then the latest picture of that CLUT stream will be applied
5122 to the remaining frames of the @code{mandelbrot} stream.
5124 @subsubsection Hald CLUT with preview
5126 A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by
5127 @code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the
5128 biggest possible square starting at the top left of the picture. The remaining
5129 padding pixels (bottom or right) will be ignored. This area can be used to add
5130 a preview of the Hald CLUT.
5132 Typically, the following generated Hald CLUT will be supported by the
5133 @code{haldclut} filter:
5136 ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "
5137 pad=iw+320 [padded_clut];
5138 smptebars=s=320x256, split [a][b];
5139 [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
5140 [main][b] overlay=W-320" -frames:v 1 clut.png
5143 It contains the original and a preview of the effect of the CLUT: SMPTE color
5144 bars are displayed on the right-top, and below the same color bars processed by
5147 Then, the effect of this Hald CLUT can be visualized with:
5149 ffplay input.mkv -vf "movie=clut.png, [in] haldclut"
5154 Flip the input video horizontally.
5156 For example, to horizontally flip the input video with @command{ffmpeg}:
5158 ffmpeg -i in.avi -vf "hflip" out.avi
5162 This filter applies a global color histogram equalization on a
5165 It can be used to correct video that has a compressed range of pixel
5166 intensities. The filter redistributes the pixel intensities to
5167 equalize their distribution across the intensity range. It may be
5168 viewed as an "automatically adjusting contrast filter". This filter is
5169 useful only for correcting degraded or poorly captured source
5172 The filter accepts the following options:
5176 Determine the amount of equalization to be applied. As the strength
5177 is reduced, the distribution of pixel intensities more-and-more
5178 approaches that of the input frame. The value must be a float number
5179 in the range [0,1] and defaults to 0.200.
5182 Set the maximum intensity that can generated and scale the output
5183 values appropriately. The strength should be set as desired and then
5184 the intensity can be limited if needed to avoid washing-out. The value
5185 must be a float number in the range [0,1] and defaults to 0.210.
5188 Set the antibanding level. If enabled the filter will randomly vary
5189 the luminance of output pixels by a small amount to avoid banding of
5190 the histogram. Possible values are @code{none}, @code{weak} or
5191 @code{strong}. It defaults to @code{none}.
5196 Compute and draw a color distribution histogram for the input video.
5198 The computed histogram is a representation of the color component
5199 distribution in an image.
5201 The filter accepts the following options:
5207 It accepts the following values:
5210 Standard histogram that displays the color components distribution in an
5211 image. Displays color graph for each color component. Shows distribution of
5212 the Y, U, V, A or R, G, B components, depending on input format, in the
5213 current frame. Below each graph a color component scale meter is shown.
5216 Displays chroma values (U/V color placement) in a two dimensional
5217 graph (which is called a vectorscope). The brighter a pixel in the
5218 vectorscope, the more pixels of the input frame correspond to that pixel
5219 (i.e., more pixels have this chroma value). The V component is displayed on
5220 the horizontal (X) axis, with the leftmost side being V = 0 and the rightmost
5221 side being V = 255. The U component is displayed on the vertical (Y) axis,
5222 with the top representing U = 0 and the bottom representing U = 255.
5224 The position of a white pixel in the graph corresponds to the chroma value of
5225 a pixel of the input clip. The graph can therefore be used to read the hue
5226 (color flavor) and the saturation (the dominance of the hue in the color). As
5227 the hue of a color changes, it moves around the square. At the center of the
5228 square the saturation is zero, which means that the corresponding pixel has no
5229 color. If the amount of a specific color is increased (while leaving the other
5230 colors unchanged) the saturation increases, and the indicator moves towards
5231 the edge of the square.
5234 Chroma values in vectorscope, similar as @code{color} but actual chroma values
5238 Per row/column color component graph. In row mode, the graph on the left side
5239 represents color component value 0 and the right side represents value = 255.
5240 In column mode, the top side represents color component value = 0 and bottom
5241 side represents value = 255.
5243 Default value is @code{levels}.
5246 Set height of level in @code{levels}. Default value is @code{200}.
5247 Allowed range is [50, 2048].
5250 Set height of color scale in @code{levels}. Default value is @code{12}.
5251 Allowed range is [0, 40].
5254 Set step for @code{waveform} mode. Smaller values are useful to find out how
5255 many values of the same luminance are distributed across input rows/columns.
5256 Default value is @code{10}. Allowed range is [1, 255].
5259 Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
5260 Default is @code{row}.
5262 @item waveform_mirror
5263 Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1}
5264 means mirrored. In mirrored mode, higher values will be represented on the left
5265 side for @code{row} mode and at the top for @code{column} mode. Default is
5266 @code{0} (unmirrored).
5269 Set display mode for @code{waveform} and @code{levels}.
5270 It accepts the following values:
5273 Display separate graph for the color components side by side in
5274 @code{row} waveform mode or one below the other in @code{column} waveform mode
5275 for @code{waveform} histogram mode. For @code{levels} histogram mode,
5276 per color component graphs are placed below each other.
5278 Using this display mode in @code{waveform} histogram mode makes it easy to
5279 spot color casts in the highlights and shadows of an image, by comparing the
5280 contours of the top and the bottom graphs of each waveform. Since whites,
5281 grays, and blacks are characterized by exactly equal amounts of red, green,
5282 and blue, neutral areas of the picture should display three waveforms of
5283 roughly equal width/height. If not, the correction is easy to perform by
5284 making level adjustments the three waveforms.
5287 Presents information identical to that in the @code{parade}, except
5288 that the graphs representing color components are superimposed directly
5291 This display mode in @code{waveform} histogram mode makes it easier to spot
5292 relative differences or similarities in overlapping areas of the color
5293 components that are supposed to be identical, such as neutral whites, grays,
5296 Default is @code{parade}.
5299 Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
5300 Default is @code{linear}.
5303 @subsection Examples
5308 Calculate and draw histogram:
5310 ffplay -i input -vf histogram
5318 This is a high precision/quality 3d denoise filter. It aims to reduce
5319 image noise, producing smooth images and making still images really
5320 still. It should enhance compressibility.
5322 It accepts the following optional parameters:
5326 A non-negative floating point number which specifies spatial luma strength.
5329 @item chroma_spatial
5330 A non-negative floating point number which specifies spatial chroma strength.
5331 It defaults to 3.0*@var{luma_spatial}/4.0.
5334 A floating point number which specifies luma temporal strength. It defaults to
5335 6.0*@var{luma_spatial}/4.0.
5338 A floating point number which specifies chroma temporal strength. It defaults to
5339 @var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}.
5344 Apply a high-quality magnification filter designed for pixel art. This filter
5345 was originally created by Maxim Stepin.
5347 It accepts the following option:
5351 Set the scaling dimension: @code{2} for @code{hq2x}, @code{3} for
5352 @code{hq3x} and @code{4} for @code{hq4x}.
5353 Default is @code{3}.
5358 Modify the hue and/or the saturation of the input.
5360 It accepts the following parameters:
5364 Specify the hue angle as a number of degrees. It accepts an expression,
5365 and defaults to "0".
5368 Specify the saturation in the [-10,10] range. It accepts an expression and
5372 Specify the hue angle as a number of radians. It accepts an
5373 expression, and defaults to "0".
5376 Specify the brightness in the [-10,10] range. It accepts an expression and
5380 @option{h} and @option{H} are mutually exclusive, and can't be
5381 specified at the same time.
5383 The @option{b}, @option{h}, @option{H} and @option{s} option values are
5384 expressions containing the following constants:
5388 frame count of the input frame starting from 0
5391 presentation timestamp of the input frame expressed in time base units
5394 frame rate of the input video, NAN if the input frame rate is unknown
5397 timestamp expressed in seconds, NAN if the input timestamp is unknown
5400 time base of the input video
5403 @subsection Examples
5407 Set the hue to 90 degrees and the saturation to 1.0:
5413 Same command but expressing the hue in radians:
5419 Rotate hue and make the saturation swing between 0
5420 and 2 over a period of 1 second:
5422 hue="H=2*PI*t: s=sin(2*PI*t)+1"
5426 Apply a 3 seconds saturation fade-in effect starting at 0:
5431 The general fade-in expression can be written as:
5433 hue="s=min(0\, max((t-START)/DURATION\, 1))"
5437 Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
5439 hue="s=max(0\, min(1\, (8-t)/3))"
5442 The general fade-out expression can be written as:
5444 hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
5449 @subsection Commands
5451 This filter supports the following commands:
5457 Modify the hue and/or the saturation and/or brightness of the input video.
5458 The command accepts the same syntax of the corresponding option.
5460 If the specified expression is not valid, it is kept at its current
5466 Detect video interlacing type.
5468 This filter tries to detect if the input is interlaced or progressive,
5469 top or bottom field first.
5471 The filter accepts the following options:
5475 Set interlacing threshold.
5477 Set progressive threshold.
5482 Deinterleave or interleave fields.
5484 This filter allows one to process interlaced images fields without
5485 deinterlacing them. Deinterleaving splits the input frame into 2
5486 fields (so called half pictures). Odd lines are moved to the top
5487 half of the output image, even lines to the bottom half.
5488 You can process (filter) them independently and then re-interleave them.
5490 The filter accepts the following options:
5494 @item chroma_mode, c
5496 Available values for @var{luma_mode}, @var{chroma_mode} and
5497 @var{alpha_mode} are:
5503 @item deinterleave, d
5504 Deinterleave fields, placing one above the other.
5507 Interleave fields. Reverse the effect of deinterleaving.
5509 Default value is @code{none}.
5512 @item chroma_swap, cs
5513 @item alpha_swap, as
5514 Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}.
5519 Simple interlacing filter from progressive contents. This interleaves upper (or
5520 lower) lines from odd frames with lower (or upper) lines from even frames,
5521 halving the frame rate and preserving image height.
5524 Original Original New Frame
5525 Frame 'j' Frame 'j+1' (tff)
5526 ========== =========== ==================
5527 Line 0 --------------------> Frame 'j' Line 0
5528 Line 1 Line 1 ----> Frame 'j+1' Line 1
5529 Line 2 ---------------------> Frame 'j' Line 2
5530 Line 3 Line 3 ----> Frame 'j+1' Line 3
5532 New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on
5535 It accepts the following optional parameters:
5539 This determines whether the interlaced frame is taken from the even
5540 (tff - default) or odd (bff) lines of the progressive frame.
5543 Enable (default) or disable the vertical lowpass filter to avoid twitter
5544 interlacing and reduce moire patterns.
5549 Deinterlace input video by applying Donald Graft's adaptive kernel
5550 deinterling. Work on interlaced parts of a video to produce
5553 The description of the accepted parameters follows.
5557 Set the threshold which affects the filter's tolerance when
5558 determining if a pixel line must be processed. It must be an integer
5559 in the range [0,255] and defaults to 10. A value of 0 will result in
5560 applying the process on every pixels.
5563 Paint pixels exceeding the threshold value to white if set to 1.
5567 Set the fields order. Swap fields if set to 1, leave fields alone if
5571 Enable additional sharpening if set to 1. Default is 0.
5574 Enable twoway sharpening if set to 1. Default is 0.
5577 @subsection Examples
5581 Apply default values:
5583 kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0
5587 Enable additional sharpening:
5593 Paint processed pixels in white:
5599 @section lenscorrection
5601 Correct radial lens distortion
5603 This filter can be used to correct for radial distortion as can result from the use
5604 of wide angle lenses, and thereby re-rectify the image. To find the right parameters
5605 one can use tools available for example as part of opencv or simply trial-and-error.
5606 To use opencv use the calibration sample (under samples/cpp) from the opencv sources
5607 and extract the k1 and k2 coefficients from the resulting matrix.
5609 Note that effectively the same filter is available in the open-source tools Krita and
5610 Digikam from the KDE project.
5612 In contrast to the @ref{vignette} filter, which can also be used to compensate lens errors,
5613 this filter corrects the distortion of the image, whereas @ref{vignette} corrects the
5614 brightness distribution, so you may want to use both filters together in certain
5615 cases, though you will have to take care of ordering, i.e. whether vignetting should
5616 be applied before or after lens correction.
5620 The filter accepts the following options:
5624 Relative x-coordinate of the focal point of the image, and thereby the center of the
5625 distrortion. This value has a range [0,1] and is expressed as fractions of the image
5628 Relative y-coordinate of the focal point of the image, and thereby the center of the
5629 distrortion. This value has a range [0,1] and is expressed as fractions of the image
5632 Coefficient of the quadratic correction term. 0.5 means no correction.
5634 Coefficient of the double quadratic correction term. 0.5 means no correction.
5637 The formula that generates the correction is:
5639 @var{r_src} = @var{r_tgt} * (1 + @var{k1} * (@var{r_tgt} / @var{r_0})^2 + @var{k2} * (@var{r_tgt} / @var{r_0})^4)
5641 where @var{r_0} is halve of the image diagonal and @var{r_src} and @var{r_tgt} are the
5642 distances from the focal point in the source and target images, respectively.
5647 Apply a 3D LUT to an input video.
5649 The filter accepts the following options:
5653 Set the 3D LUT file name.
5655 Currently supported formats:
5667 Select interpolation mode.
5669 Available values are:
5673 Use values from the nearest defined point.
5675 Interpolate values using the 8 points defining a cube.
5677 Interpolate values using a tetrahedron.
5681 @section lut, lutrgb, lutyuv
5683 Compute a look-up table for binding each pixel component input value
5684 to an output value, and apply it to the input video.
5686 @var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
5687 to an RGB input video.
5689 These filters accept the following parameters:
5692 set first pixel component expression
5694 set second pixel component expression
5696 set third pixel component expression
5698 set fourth pixel component expression, corresponds to the alpha component
5701 set red component expression
5703 set green component expression
5705 set blue component expression
5707 alpha component expression
5710 set Y/luminance component expression
5712 set U/Cb component expression
5714 set V/Cr component expression
5717 Each of them specifies the expression to use for computing the lookup table for
5718 the corresponding pixel component values.
5720 The exact component associated to each of the @var{c*} options depends on the
5723 The @var{lut} filter requires either YUV or RGB pixel formats in input,
5724 @var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV.
5726 The expressions can contain the following constants and functions:
5731 The input width and height.
5734 The input value for the pixel component.
5737 The input value, clipped to the @var{minval}-@var{maxval} range.
5740 The maximum value for the pixel component.
5743 The minimum value for the pixel component.
5746 The negated value for the pixel component value, clipped to the
5747 @var{minval}-@var{maxval} range; it corresponds to the expression
5748 "maxval-clipval+minval".
5751 The computed value in @var{val}, clipped to the
5752 @var{minval}-@var{maxval} range.
5754 @item gammaval(gamma)
5755 The computed gamma correction value of the pixel component value,
5756 clipped to the @var{minval}-@var{maxval} range. It corresponds to the
5758 "pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
5762 All expressions default to "val".
5764 @subsection Examples
5770 lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
5771 lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
5774 The above is the same as:
5776 lutrgb="r=negval:g=negval:b=negval"
5777 lutyuv="y=negval:u=negval:v=negval"
5787 Remove chroma components, turning the video into a graytone image:
5789 lutyuv="u=128:v=128"
5793 Apply a luma burning effect:
5799 Remove green and blue components:
5805 Set a constant alpha channel value on input:
5807 format=rgba,lutrgb=a="maxval-minval/2"
5811 Correct luminance gamma by a factor of 0.5:
5813 lutyuv=y=gammaval(0.5)
5817 Discard least significant bits of luma:
5819 lutyuv=y='bitand(val, 128+64+32)'
5823 @section mergeplanes
5825 Merge color channel components from several video streams.
5827 The filter accepts up to 4 input streams, and merge selected input
5828 planes to the output video.
5830 This filter accepts the following options:
5833 Set input to output plane mapping. Default is @code{0}.
5835 The mappings is specified as a bitmap. It should be specified as a
5836 hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
5837 mapping for the first plane of the output stream. 'A' sets the number of
5838 the input stream to use (from 0 to 3), and 'a' the plane number of the
5839 corresponding input to use (from 0 to 3). The rest of the mappings is
5840 similar, 'Bb' describes the mapping for the output stream second
5841 plane, 'Cc' describes the mapping for the output stream third plane and
5842 'Dd' describes the mapping for the output stream fourth plane.
5845 Set output pixel format. Default is @code{yuva444p}.
5848 @subsection Examples
5852 Merge three gray video streams of same width and height into single video stream:
5854 [a0][a1][a2]mergeplanes=0x001020:yuv444p
5858 Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream:
5860 [a0][a1]mergeplanes=0x00010210:yuva444p
5864 Swap Y and A plane in yuva444p stream:
5866 format=yuva444p,mergeplanes=0x03010200:yuva444p
5870 Swap U and V plane in yuv420p stream:
5872 format=yuv420p,mergeplanes=0x000201:yuv420p
5876 Cast a rgb24 clip to yuv444p:
5878 format=rgb24,mergeplanes=0x000102:yuv444p
5884 Apply motion-compensation deinterlacing.
5886 It needs one field per frame as input and must thus be used together
5887 with yadif=1/3 or equivalent.
5889 This filter accepts the following options:
5892 Set the deinterlacing mode.
5894 It accepts one of the following values:
5899 use iterative motion estimation
5901 like @samp{slow}, but use multiple reference frames.
5903 Default value is @samp{fast}.
5906 Set the picture field parity assumed for the input video. It must be
5907 one of the following values:
5911 assume top field first
5913 assume bottom field first
5916 Default value is @samp{bff}.
5919 Set per-block quantization parameter (QP) used by the internal
5922 Higher values should result in a smoother motion vector field but less
5923 optimal individual vectors. Default value is 1.
5928 Apply an MPlayer filter to the input video.
5930 This filter provides a wrapper around some of the filters of
5933 This wrapper is considered experimental. Some of the wrapped filters
5934 may not work properly and we may drop support for them, as they will
5935 be implemented natively into FFmpeg. Thus you should avoid
5936 depending on them when writing portable scripts.
5938 The filter accepts the parameters:
5939 @var{filter_name}[:=]@var{filter_params}
5941 @var{filter_name} is the name of a supported MPlayer filter,
5942 @var{filter_params} is a string containing the parameters accepted by
5945 The list of the currently supported filters follows:
5956 The parameter syntax and behavior for the listed filters are the same
5957 of the corresponding MPlayer filters. For detailed instructions check
5958 the "VIDEO FILTERS" section in the MPlayer manual.
5960 @subsection Examples
5964 Adjust gamma, brightness, contrast:
5970 See also mplayer(1), @url{http://www.mplayerhq.hu/}.
5974 Drop frames that do not differ greatly from the previous frame in
5975 order to reduce frame rate.
5977 The main use of this filter is for very-low-bitrate encoding
5978 (e.g. streaming over dialup modem), but it could in theory be used for
5979 fixing movies that were inverse-telecined incorrectly.
5981 A description of the accepted options follows.
5985 Set the maximum number of consecutive frames which can be dropped (if
5986 positive), or the minimum interval between dropped frames (if
5987 negative). If the value is 0, the frame is dropped unregarding the
5988 number of previous sequentially dropped frames.
5995 Set the dropping threshold values.
5997 Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and
5998 represent actual pixel value differences, so a threshold of 64
5999 corresponds to 1 unit of difference for each pixel, or the same spread
6000 out differently over the block.
6002 A frame is a candidate for dropping if no 8x8 blocks differ by more
6003 than a threshold of @option{hi}, and if no more than @option{frac} blocks (1
6004 meaning the whole image) differ by more than a threshold of @option{lo}.
6006 Default value for @option{hi} is 64*12, default value for @option{lo} is
6007 64*5, and default value for @option{frac} is 0.33.
6015 It accepts an integer in input; if non-zero it negates the
6016 alpha component (if available). The default value in input is 0.
6020 Force libavfilter not to use any of the specified pixel formats for the
6021 input to the next filter.
6023 It accepts the following parameters:
6027 A '|'-separated list of pixel format names, such as
6028 apix_fmts=yuv420p|monow|rgb24".
6032 @subsection Examples
6036 Force libavfilter to use a format different from @var{yuv420p} for the
6037 input to the vflip filter:
6039 noformat=pix_fmts=yuv420p,vflip
6043 Convert the input video to any of the formats not contained in the list:
6045 noformat=yuv420p|yuv444p|yuv410p
6051 Add noise on video input frame.
6053 The filter accepts the following options:
6061 Set noise seed for specific pixel component or all pixel components in case
6062 of @var{all_seed}. Default value is @code{123457}.
6064 @item all_strength, alls
6065 @item c0_strength, c0s
6066 @item c1_strength, c1s
6067 @item c2_strength, c2s
6068 @item c3_strength, c3s
6069 Set noise strength for specific pixel component or all pixel components in case
6070 @var{all_strength}. Default value is @code{0}. Allowed range is [0, 100].
6072 @item all_flags, allf
6077 Set pixel component flags or set flags for all components if @var{all_flags}.
6078 Available values for component flags are:
6081 averaged temporal noise (smoother)
6083 mix random noise with a (semi)regular pattern
6085 temporal noise (noise pattern changes between frames)
6087 uniform noise (gaussian otherwise)
6091 @subsection Examples
6093 Add temporal and uniform noise to input video:
6095 noise=alls=20:allf=t+u
6100 Pass the video source unchanged to the output.
6104 Apply a video transform using libopencv.
6106 To enable this filter, install the libopencv library and headers and
6107 configure FFmpeg with @code{--enable-libopencv}.
6109 It accepts the following parameters:
6114 The name of the libopencv filter to apply.
6117 The parameters to pass to the libopencv filter. If not specified, the default
6122 Refer to the official libopencv documentation for more precise
6124 @url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
6126 Several libopencv filters are supported; see the following subsections.
6131 Dilate an image by using a specific structuring element.
6132 It corresponds to the libopencv function @code{cvDilate}.
6134 It accepts the parameters: @var{struct_el}|@var{nb_iterations}.
6136 @var{struct_el} represents a structuring element, and has the syntax:
6137 @var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
6139 @var{cols} and @var{rows} represent the number of columns and rows of
6140 the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
6141 point, and @var{shape} the shape for the structuring element. @var{shape}
6142 must be "rect", "cross", "ellipse", or "custom".
6144 If the value for @var{shape} is "custom", it must be followed by a
6145 string of the form "=@var{filename}". The file with name
6146 @var{filename} is assumed to represent a binary image, with each
6147 printable character corresponding to a bright pixel. When a custom
6148 @var{shape} is used, @var{cols} and @var{rows} are ignored, the number
6149 or columns and rows of the read file are assumed instead.
6151 The default value for @var{struct_el} is "3x3+0x0/rect".
6153 @var{nb_iterations} specifies the number of times the transform is
6154 applied to the image, and defaults to 1.
6158 # Use the default values
6161 # Dilate using a structuring element with a 5x5 cross, iterating two times
6162 ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2
6164 # Read the shape from the file diamond.shape, iterating two times.
6165 # The file diamond.shape may contain a pattern of characters like this
6171 # The specified columns and rows are ignored
6172 # but the anchor point coordinates are not
6173 ocv=dilate:0x0+2x2/custom=diamond.shape|2
6178 Erode an image by using a specific structuring element.
6179 It corresponds to the libopencv function @code{cvErode}.
6181 It accepts the parameters: @var{struct_el}:@var{nb_iterations},
6182 with the same syntax and semantics as the @ref{dilate} filter.
6186 Smooth the input video.
6188 The filter takes the following parameters:
6189 @var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}.
6191 @var{type} is the type of smooth filter to apply, and must be one of
6192 the following values: "blur", "blur_no_scale", "median", "gaussian",
6193 or "bilateral". The default value is "gaussian".
6195 The meaning of @var{param1}, @var{param2}, @var{param3}, and @var{param4}
6196 depend on the smooth type. @var{param1} and
6197 @var{param2} accept integer positive values or 0. @var{param3} and
6198 @var{param4} accept floating point values.
6200 The default value for @var{param1} is 3. The default value for the
6201 other parameters is 0.
6203 These parameters correspond to the parameters assigned to the
6204 libopencv function @code{cvSmooth}.
6209 Overlay one video on top of another.
6211 It takes two inputs and has one output. The first input is the "main"
6212 video on which the second input is overlayed.
6214 It accepts the following parameters:
6216 A description of the accepted options follows.
6221 Set the expression for the x and y coordinates of the overlayed video
6222 on the main video. Default value is "0" for both expressions. In case
6223 the expression is invalid, it is set to a huge value (meaning that the
6224 overlay will not be displayed within the output visible area).
6227 The action to take when EOF is encountered on the secondary input; it accepts
6228 one of the following values:
6232 Repeat the last frame (the default).
6236 Pass the main input through.
6240 Set when the expressions for @option{x}, and @option{y} are evaluated.
6242 It accepts the following values:
6245 only evaluate expressions once during the filter initialization or
6246 when a command is processed
6249 evaluate expressions for each incoming frame
6252 Default value is @samp{frame}.
6255 If set to 1, force the output to terminate when the shortest input
6256 terminates. Default value is 0.
6259 Set the format for the output video.
6261 It accepts the following values:
6276 Default value is @samp{yuv420}.
6278 @item rgb @emph{(deprecated)}
6279 If set to 1, force the filter to accept inputs in the RGB
6280 color space. Default value is 0. This option is deprecated, use
6281 @option{format} instead.
6284 If set to 1, force the filter to draw the last overlay frame over the
6285 main input until the end of the stream. A value of 0 disables this
6286 behavior. Default value is 1.
6289 The @option{x}, and @option{y} expressions can contain the following
6295 The main input width and height.
6299 The overlay input width and height.
6303 The computed values for @var{x} and @var{y}. They are evaluated for
6308 horizontal and vertical chroma subsample values of the output
6309 format. For example for the pixel format "yuv422p" @var{hsub} is 2 and
6313 the number of input frame, starting from 0
6316 the position in the file of the input frame, NAN if unknown
6319 The timestamp, expressed in seconds. It's NAN if the input timestamp is unknown.
6323 Note that the @var{n}, @var{pos}, @var{t} variables are available only
6324 when evaluation is done @emph{per frame}, and will evaluate to NAN
6325 when @option{eval} is set to @samp{init}.
6327 Be aware that frames are taken from each input video in timestamp
6328 order, hence, if their initial timestamps differ, it is a good idea
6329 to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
6330 have them begin in the same zero timestamp, as the example for
6331 the @var{movie} filter does.
6333 You can chain together more overlays but you should test the
6334 efficiency of such approach.
6336 @subsection Commands
6338 This filter supports the following commands:
6342 Modify the x and y of the overlay input.
6343 The command accepts the same syntax of the corresponding option.
6345 If the specified expression is not valid, it is kept at its current
6349 @subsection Examples
6353 Draw the overlay at 10 pixels from the bottom right corner of the main
6356 overlay=main_w-overlay_w-10:main_h-overlay_h-10
6359 Using named options the example above becomes:
6361 overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10
6365 Insert a transparent PNG logo in the bottom left corner of the input,
6366 using the @command{ffmpeg} tool with the @code{-filter_complex} option:
6368 ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
6372 Insert 2 different transparent PNG logos (second logo on bottom
6373 right corner) using the @command{ffmpeg} tool:
6375 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
6379 Add a transparent color layer on top of the main video; @code{WxH}
6380 must specify the size of the main input to the overlay filter:
6382 color=color=red@@.3:size=WxH [over]; [in][over] overlay [out]
6386 Play an original video and a filtered version (here with the deshake
6387 filter) side by side using the @command{ffplay} tool:
6389 ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
6392 The above command is the same as:
6394 ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
6398 Make a sliding overlay appearing from the left to the right top part of the
6399 screen starting since time 2:
6401 overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0
6405 Compose output by putting two input videos side to side:
6407 ffmpeg -i left.avi -i right.avi -filter_complex "
6408 nullsrc=size=200x100 [background];
6409 [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
6410 [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
6411 [background][left] overlay=shortest=1 [background+left];
6412 [background+left][right] overlay=shortest=1:x=100 [left+right]
6417 Mask 10-20 seconds of a video by applying the delogo filter to a section
6419 ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025 -b:v 9000k
6420 -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]'
6425 Chain several overlays in cascade:
6427 nullsrc=s=200x200 [bg];
6428 testsrc=s=100x100, split=4 [in0][in1][in2][in3];
6429 [in0] lutrgb=r=0, [bg] overlay=0:0 [mid0];
6430 [in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1];
6431 [in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2];
6432 [in3] null, [mid2] overlay=100:100 [out0]
6439 Apply Overcomplete Wavelet denoiser.
6441 The filter accepts the following options:
6447 Larger depth values will denoise lower frequency components more, but
6448 slow down filtering.
6450 Must be an int in the range 8-16, default is @code{8}.
6452 @item luma_strength, ls
6455 Must be a double value in the range 0-1000, default is @code{1.0}.
6457 @item chroma_strength, cs
6458 Set chroma strength.
6460 Must be a double value in the range 0-1000, default is @code{1.0}.
6465 Add paddings to the input image, and place the original input at the
6466 provided @var{x}, @var{y} coordinates.
6468 It accepts the following parameters:
6473 Specify an expression for the size of the output image with the
6474 paddings added. If the value for @var{width} or @var{height} is 0, the
6475 corresponding input size is used for the output.
6477 The @var{width} expression can reference the value set by the
6478 @var{height} expression, and vice versa.
6480 The default value of @var{width} and @var{height} is 0.
6484 Specify the offsets to place the input image at within the padded area,
6485 with respect to the top/left border of the output image.
6487 The @var{x} expression can reference the value set by the @var{y}
6488 expression, and vice versa.
6490 The default value of @var{x} and @var{y} is 0.
6493 Specify the color of the padded area. For the syntax of this option,
6494 check the "Color" section in the ffmpeg-utils manual.
6496 The default value of @var{color} is "black".
6499 The value for the @var{width}, @var{height}, @var{x}, and @var{y}
6500 options are expressions containing the following constants:
6505 The input video width and height.
6509 These are the same as @var{in_w} and @var{in_h}.
6513 The output width and height (the size of the padded area), as
6514 specified by the @var{width} and @var{height} expressions.
6518 These are the same as @var{out_w} and @var{out_h}.
6522 The x and y offsets as specified by the @var{x} and @var{y}
6523 expressions, or NAN if not yet specified.
6526 same as @var{iw} / @var{ih}
6529 input sample aspect ratio
6532 input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
6536 The horizontal and vertical chroma subsample values. For example for the
6537 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
6540 @subsection Examples
6544 Add paddings with the color "violet" to the input video. The output video
6545 size is 640x480, and the top-left corner of the input video is placed at
6548 pad=640:480:0:40:violet
6551 The example above is equivalent to the following command:
6553 pad=width=640:height=480:x=0:y=40:color=violet
6557 Pad the input to get an output with dimensions increased by 3/2,
6558 and put the input video at the center of the padded area:
6560 pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
6564 Pad the input to get a squared output with size equal to the maximum
6565 value between the input width and height, and put the input video at
6566 the center of the padded area:
6568 pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
6572 Pad the input to get a final w/h ratio of 16:9:
6574 pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
6578 In case of anamorphic video, in order to set the output display aspect
6579 correctly, it is necessary to use @var{sar} in the expression,
6580 according to the relation:
6582 (ih * X / ih) * sar = output_dar
6583 X = output_dar / sar
6586 Thus the previous example needs to be modified to:
6588 pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"
6592 Double the output size and put the input video in the bottom-right
6593 corner of the output padded area:
6595 pad="2*iw:2*ih:ow-iw:oh-ih"
6599 @section perspective
6601 Correct perspective of video not recorded perpendicular to the screen.
6603 A description of the accepted parameters follows.
6614 Set coordinates expression for top left, top right, bottom left and bottom right corners.
6615 Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged.
6617 The expressions can use the following variables:
6622 the width and height of video frame.
6626 Set interpolation for perspective correction.
6628 It accepts the following values:
6634 Default value is @samp{linear}.
6639 Delay interlaced video by one field time so that the field order changes.
6641 The intended use is to fix PAL movies that have been captured with the
6642 opposite field order to the film-to-video transfer.
6644 A description of the accepted parameters follows.
6650 It accepts the following values:
6653 Capture field order top-first, transfer bottom-first.
6654 Filter will delay the bottom field.
6657 Capture field order bottom-first, transfer top-first.
6658 Filter will delay the top field.
6661 Capture and transfer with the same field order. This mode only exists
6662 for the documentation of the other options to refer to, but if you
6663 actually select it, the filter will faithfully do nothing.
6666 Capture field order determined automatically by field flags, transfer
6668 Filter selects among @samp{t} and @samp{b} modes on a frame by frame
6669 basis using field flags. If no field information is available,
6670 then this works just like @samp{u}.
6673 Capture unknown or varying, transfer opposite.
6674 Filter selects among @samp{t} and @samp{b} on a frame by frame basis by
6675 analyzing the images and selecting the alternative that produces best
6676 match between the fields.
6679 Capture top-first, transfer unknown or varying.
6680 Filter selects among @samp{t} and @samp{p} using image analysis.
6683 Capture bottom-first, transfer unknown or varying.
6684 Filter selects among @samp{b} and @samp{p} using image analysis.
6687 Capture determined by field flags, transfer unknown or varying.
6688 Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and
6689 image analysis. If no field information is available, then this works just
6690 like @samp{U}. This is the default mode.
6693 Both capture and transfer unknown or varying.
6694 Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only.
6698 @section pixdesctest
6700 Pixel format descriptor test filter, mainly useful for internal
6701 testing. The output video should be equal to the input video.
6705 format=monow, pixdesctest
6708 can be used to test the monowhite pixel format descriptor definition.
6712 Enable the specified chain of postprocessing subfilters using libpostproc. This
6713 library should be automatically selected with a GPL build (@code{--enable-gpl}).
6714 Subfilters must be separated by '/' and can be disabled by prepending a '-'.
6715 Each subfilter and some options have a short and a long name that can be used
6716 interchangeably, i.e. dr/dering are the same.
6718 The filters accept the following options:
6722 Set postprocessing subfilters string.
6725 All subfilters share common options to determine their scope:
6729 Honor the quality commands for this subfilter.
6732 Do chrominance filtering, too (default).
6735 Do luminance filtering only (no chrominance).
6738 Do chrominance filtering only (no luminance).
6741 These options can be appended after the subfilter name, separated by a '|'.
6743 Available subfilters are:
6746 @item hb/hdeblock[|difference[|flatness]]
6747 Horizontal deblocking filter
6750 Difference factor where higher values mean more deblocking (default: @code{32}).
6752 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6755 @item vb/vdeblock[|difference[|flatness]]
6756 Vertical deblocking filter
6759 Difference factor where higher values mean more deblocking (default: @code{32}).
6761 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6764 @item ha/hadeblock[|difference[|flatness]]
6765 Accurate horizontal deblocking filter
6768 Difference factor where higher values mean more deblocking (default: @code{32}).
6770 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6773 @item va/vadeblock[|difference[|flatness]]
6774 Accurate vertical deblocking filter
6777 Difference factor where higher values mean more deblocking (default: @code{32}).
6779 Flatness threshold where lower values mean more deblocking (default: @code{39}).
6783 The horizontal and vertical deblocking filters share the difference and
6784 flatness values so you cannot set different horizontal and vertical
6789 Experimental horizontal deblocking filter
6792 Experimental vertical deblocking filter
6797 @item tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise reducer
6800 larger -> stronger filtering
6802 larger -> stronger filtering
6804 larger -> stronger filtering
6807 @item al/autolevels[:f/fullyrange], automatic brightness / contrast correction
6810 Stretch luminance to @code{0-255}.
6813 @item lb/linblenddeint
6814 Linear blend deinterlacing filter that deinterlaces the given block by
6815 filtering all lines with a @code{(1 2 1)} filter.
6817 @item li/linipoldeint
6818 Linear interpolating deinterlacing filter that deinterlaces the given block by
6819 linearly interpolating every second line.
6821 @item ci/cubicipoldeint
6822 Cubic interpolating deinterlacing filter deinterlaces the given block by
6823 cubically interpolating every second line.
6825 @item md/mediandeint
6826 Median deinterlacing filter that deinterlaces the given block by applying a
6827 median filter to every second line.
6829 @item fd/ffmpegdeint
6830 FFmpeg deinterlacing filter that deinterlaces the given block by filtering every
6831 second line with a @code{(-1 4 2 4 -1)} filter.
6834 Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given
6835 block by filtering all lines with a @code{(-1 2 6 2 -1)} filter.
6837 @item fq/forceQuant[|quantizer]
6838 Overrides the quantizer table from the input with the constant quantizer you
6846 Default pp filter combination (@code{hb|a,vb|a,dr|a})
6849 Fast pp filter combination (@code{h1|a,v1|a,dr|a})
6852 High quality pp filter combination (@code{ha|a|128|7,va|a,dr|a})
6855 @subsection Examples
6859 Apply horizontal and vertical deblocking, deringing and automatic
6860 brightness/contrast:
6866 Apply default filters without brightness/contrast correction:
6872 Apply default filters and temporal denoiser:
6874 pp=default/tmpnoise|1|2|3
6878 Apply deblocking on luminance only, and switch vertical deblocking on or off
6879 automatically depending on available CPU time:
6887 Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
6888 Ratio) between two input videos.
6890 This filter takes in input two input videos, the first input is
6891 considered the "main" source and is passed unchanged to the
6892 output. The second input is used as a "reference" video for computing
6895 Both video inputs must have the same resolution and pixel format for
6896 this filter to work correctly. Also it assumes that both inputs
6897 have the same number of frames, which are compared one by one.
6899 The obtained average PSNR is printed through the logging system.
6901 The filter stores the accumulated MSE (mean squared error) of each
6902 frame, and at the end of the processing it is averaged across all frames
6903 equally, and the following formula is applied to obtain the PSNR:
6906 PSNR = 10*log10(MAX^2/MSE)
6909 Where MAX is the average of the maximum values of each component of the
6912 The description of the accepted parameters follows.
6916 If specified the filter will use the named file to save the PSNR of
6917 each individual frame.
6920 The file printed if @var{stats_file} is selected, contains a sequence of
6921 key/value pairs of the form @var{key}:@var{value} for each compared
6924 A description of each shown parameter follows:
6928 sequential number of the input frame, starting from 1
6931 Mean Square Error pixel-by-pixel average difference of the compared
6932 frames, averaged over all the image components.
6934 @item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
6935 Mean Square Error pixel-by-pixel average difference of the compared
6936 frames for the component specified by the suffix.
6938 @item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
6939 Peak Signal to Noise ratio of the compared frames for the component
6940 specified by the suffix.
6945 movie=ref_movie.mpg, setpts=PTS-STARTPTS [main];
6946 [main][ref] psnr="stats_file=stats.log" [out]
6949 On this example the input file being processed is compared with the
6950 reference file @file{ref_movie.mpg}. The PSNR of each individual frame
6951 is stored in @file{stats.log}.
6956 Pulldown reversal (inverse telecine) filter, capable of handling mixed
6957 hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive
6960 The pullup filter is designed to take advantage of future context in making
6961 its decisions. This filter is stateless in the sense that it does not lock
6962 onto a pattern to follow, but it instead looks forward to the following
6963 fields in order to identify matches and rebuild progressive frames.
6965 To produce content with an even framerate, insert the fps filter after
6966 pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps,
6967 @code{fps=24} for 30fps and the (rare) telecined 25fps input.
6969 The filter accepts the following options:
6976 These options set the amount of "junk" to ignore at the left, right, top, and
6977 bottom of the image, respectively. Left and right are in units of 8 pixels,
6978 while top and bottom are in units of 2 lines.
6979 The default is 8 pixels on each side.
6982 Set the strict breaks. Setting this option to 1 will reduce the chances of
6983 filter generating an occasional mismatched frame, but it may also cause an
6984 excessive number of frames to be dropped during high motion sequences.
6985 Conversely, setting it to -1 will make filter match fields more easily.
6986 This may help processing of video where there is slight blurring between
6987 the fields, but may also cause there to be interlaced frames in the output.
6988 Default value is @code{0}.
6991 Set the metric plane to use. It accepts the following values:
6997 Use chroma blue plane.
7000 Use chroma red plane.
7003 This option may be set to use chroma plane instead of the default luma plane
7004 for doing filter's computations. This may improve accuracy on very clean
7005 source material, but more likely will decrease accuracy, especially if there
7006 is chroma noise (rainbow effect) or any grayscale video.
7007 The main purpose of setting @option{mp} to a chroma plane is to reduce CPU
7008 load and make pullup usable in realtime on slow machines.
7011 For best results (without duplicated frames in the output file) it is
7012 necessary to change the output frame rate. For example, to inverse
7013 telecine NTSC input:
7015 ffmpeg -i input -vf pullup -r 24000/1001 ...
7020 Suppress a TV station logo, using an image file to determine which
7021 pixels comprise the logo. It works by filling in the pixels that
7022 comprise the logo with neighboring pixels.
7024 The filter accepts the following options:
7028 Set the filter bitmap file, which can be any image format supported by
7029 libavformat. The width and height of the image file must match those of the
7030 video stream being processed.
7033 Pixels in the provided bitmap image with a value of zero are not
7034 considered part of the logo, non-zero pixels are considered part of
7035 the logo. If you use white (255) for the logo and black (0) for the
7036 rest, you will be safe. For making the filter bitmap, it is
7037 recommended to take a screen capture of a black frame with the logo
7038 visible, and then using a threshold filter followed by the erode
7039 filter once or twice.
7041 If needed, little splotches can be fixed manually. Remember that if
7042 logo pixels are not covered, the filter quality will be much
7043 reduced. Marking too many pixels as part of the logo does not hurt as
7044 much, but it will increase the amount of blurring needed to cover over
7045 the image and will destroy more information than necessary, and extra
7046 pixels will slow things down on a large logo.
7050 Rotate video by an arbitrary angle expressed in radians.
7052 The filter accepts the following options:
7054 A description of the optional parameters follows.
7057 Set an expression for the angle by which to rotate the input video
7058 clockwise, expressed as a number of radians. A negative value will
7059 result in a counter-clockwise rotation. By default it is set to "0".
7061 This expression is evaluated for each frame.
7064 Set the output width expression, default value is "iw".
7065 This expression is evaluated just once during configuration.
7068 Set the output height expression, default value is "ih".
7069 This expression is evaluated just once during configuration.
7072 Enable bilinear interpolation if set to 1, a value of 0 disables
7073 it. Default value is 1.
7076 Set the color used to fill the output area not covered by the rotated
7077 image. For the generalsyntax of this option, check the "Color" section in the
7078 ffmpeg-utils manual. If the special value "none" is selected then no
7079 background is printed (useful for example if the background is never shown).
7081 Default value is "black".
7084 The expressions for the angle and the output size can contain the
7085 following constants and functions:
7089 sequential number of the input frame, starting from 0. It is always NAN
7090 before the first frame is filtered.
7093 time in seconds of the input frame, it is set to 0 when the filter is
7094 configured. It is always NAN before the first frame is filtered.
7098 horizontal and vertical chroma subsample values. For example for the
7099 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7103 the input video width and height
7107 the output width and height, that is the size of the padded area as
7108 specified by the @var{width} and @var{height} expressions
7112 the minimal width/height required for completely containing the input
7113 video rotated by @var{a} radians.
7115 These are only available when computing the @option{out_w} and
7116 @option{out_h} expressions.
7119 @subsection Examples
7123 Rotate the input by PI/6 radians clockwise:
7129 Rotate the input by PI/6 radians counter-clockwise:
7135 Rotate the input by 45 degrees clockwise:
7141 Apply a constant rotation with period T, starting from an angle of PI/3:
7143 rotate=PI/3+2*PI*t/T
7147 Make the input video rotation oscillating with a period of T
7148 seconds and an amplitude of A radians:
7150 rotate=A*sin(2*PI/T*t)
7154 Rotate the video, output size is chosen so that the whole rotating
7155 input video is always completely contained in the output:
7157 rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'
7161 Rotate the video, reduce the output size so that no background is ever
7164 rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none
7168 @subsection Commands
7170 The filter supports the following commands:
7174 Set the angle expression.
7175 The command accepts the same syntax of the corresponding option.
7177 If the specified expression is not valid, it is kept at its current
7183 Apply Shape Adaptive Blur.
7185 The filter accepts the following options:
7188 @item luma_radius, lr
7189 Set luma blur filter strength, must be a value in range 0.1-4.0, default
7190 value is 1.0. A greater value will result in a more blurred image, and
7191 in slower processing.
7193 @item luma_pre_filter_radius, lpfr
7194 Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default
7197 @item luma_strength, ls
7198 Set luma maximum difference between pixels to still be considered, must
7199 be a value in the 0.1-100.0 range, default value is 1.0.
7201 @item chroma_radius, cr
7202 Set chroma blur filter strength, must be a value in range 0.1-4.0. A
7203 greater value will result in a more blurred image, and in slower
7206 @item chroma_pre_filter_radius, cpfr
7207 Set chroma pre-filter radius, must be a value in the 0.1-2.0 range.
7209 @item chroma_strength, cs
7210 Set chroma maximum difference between pixels to still be considered,
7211 must be a value in the 0.1-100.0 range.
7214 Each chroma option value, if not explicitly specified, is set to the
7215 corresponding luma option value.
7220 Scale (resize) the input video, using the libswscale library.
7222 The scale filter forces the output display aspect ratio to be the same
7223 of the input, by changing the output sample aspect ratio.
7225 If the input image format is different from the format requested by
7226 the next filter, the scale filter will convert the input to the
7230 The filter accepts the following options, or any of the options
7231 supported by the libswscale scaler.
7233 See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for
7234 the complete list of scaler options.
7239 Set the output video dimension expression. Default value is the input
7242 If the value is 0, the input width is used for the output.
7244 If one of the values is -1, the scale filter will use a value that
7245 maintains the aspect ratio of the input image, calculated from the
7246 other specified dimension. If both of them are -1, the input size is
7249 If one of the values is -n with n > 1, the scale filter will also use a value
7250 that maintains the aspect ratio of the input image, calculated from the other
7251 specified dimension. After that it will, however, make sure that the calculated
7252 dimension is divisible by n and adjust the value if necessary.
7254 See below for the list of accepted constants for use in the dimension
7258 Set the interlacing mode. It accepts the following values:
7262 Force interlaced aware scaling.
7265 Do not apply interlaced scaling.
7268 Select interlaced aware scaling depending on whether the source frames
7269 are flagged as interlaced or not.
7272 Default value is @samp{0}.
7275 Set libswscale scaling flags. See
7276 @ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the
7277 complete list of values. If not explicitly specified the filter applies
7281 Set the video size. For the syntax of this option, check the "Video size"
7282 section in the ffmpeg-utils manual.
7284 @item in_color_matrix
7285 @item out_color_matrix
7286 Set in/output YCbCr color space type.
7288 This allows the autodetected value to be overridden as well as allows forcing
7289 a specific value used for the output and encoder.
7291 If not specified, the color space type depends on the pixel format.
7297 Choose automatically.
7300 Format conforming to International Telecommunication Union (ITU)
7301 Recommendation BT.709.
7304 Set color space conforming to the United States Federal Communications
7305 Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a).
7308 Set color space conforming to:
7312 ITU Radiocommunication Sector (ITU-R) Recommendation BT.601
7315 ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G
7318 Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004
7323 Set color space conforming to SMPTE ST 240:1999.
7328 Set in/output YCbCr sample range.
7330 This allows the autodetected value to be overridden as well as allows forcing
7331 a specific value used for the output and encoder. If not specified, the
7332 range depends on the pixel format. Possible values:
7336 Choose automatically.
7339 Set full range (0-255 in case of 8-bit luma).
7342 Set "MPEG" range (16-235 in case of 8-bit luma).
7345 @item force_original_aspect_ratio
7346 Enable decreasing or increasing output video width or height if necessary to
7347 keep the original aspect ratio. Possible values:
7351 Scale the video as specified and disable this feature.
7354 The output video dimensions will automatically be decreased if needed.
7357 The output video dimensions will automatically be increased if needed.
7361 One useful instance of this option is that when you know a specific device's
7362 maximum allowed resolution, you can use this to limit the output video to
7363 that, while retaining the aspect ratio. For example, device A allows
7364 1280x720 playback, and your video is 1920x800. Using this option (set it to
7365 decrease) and specifying 1280x720 to the command line makes the output
7368 Please note that this is a different thing than specifying -1 for @option{w}
7369 or @option{h}, you still need to specify the output resolution for this option
7374 The values of the @option{w} and @option{h} options are expressions
7375 containing the following constants:
7380 The input width and height
7384 These are the same as @var{in_w} and @var{in_h}.
7388 The output (scaled) width and height
7392 These are the same as @var{out_w} and @var{out_h}
7395 The same as @var{iw} / @var{ih}
7398 input sample aspect ratio
7401 The input display aspect ratio. Calculated from @code{(iw / ih) * sar}.
7405 horizontal and vertical input chroma subsample values. For example for the
7406 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7410 horizontal and vertical output chroma subsample values. For example for the
7411 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7414 @subsection Examples
7418 Scale the input video to a size of 200x100
7423 This is equivalent to:
7434 Specify a size abbreviation for the output size:
7439 which can also be written as:
7445 Scale the input to 2x:
7451 The above is the same as:
7457 Scale the input to 2x with forced interlaced scaling:
7459 scale=2*iw:2*ih:interl=1
7463 Scale the input to half size:
7469 Increase the width, and set the height to the same size:
7482 Increase the height, and set the width to 3/2 of the height:
7484 scale=w=3/2*oh:h=3/5*ih
7488 Increase the size, making the size a multiple of the chroma
7491 scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
7495 Increase the width to a maximum of 500 pixels,
7496 keeping the same aspect ratio as the input:
7498 scale=w='min(500\, iw*3/2):h=-1'
7502 @section separatefields
7504 The @code{separatefields} takes a frame-based video input and splits
7505 each frame into its components fields, producing a new half height clip
7506 with twice the frame rate and twice the frame count.
7508 This filter use field-dominance information in frame to decide which
7509 of each pair of fields to place first in the output.
7510 If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter.
7512 @section setdar, setsar
7514 The @code{setdar} filter sets the Display Aspect Ratio for the filter
7517 This is done by changing the specified Sample (aka Pixel) Aspect
7518 Ratio, according to the following equation:
7520 @var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
7523 Keep in mind that the @code{setdar} filter does not modify the pixel
7524 dimensions of the video frame. Also, the display aspect ratio set by
7525 this filter may be changed by later filters in the filterchain,
7526 e.g. in case of scaling or if another "setdar" or a "setsar" filter is
7529 The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
7530 the filter output video.
7532 Note that as a consequence of the application of this filter, the
7533 output display aspect ratio will change according to the equation
7536 Keep in mind that the sample aspect ratio set by the @code{setsar}
7537 filter may be changed by later filters in the filterchain, e.g. if
7538 another "setsar" or a "setdar" filter is applied.
7540 It accepts the following parameters:
7543 @item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only)
7544 Set the aspect ratio used by the filter.
7546 The parameter can be a floating point number string, an expression, or
7547 a string of the form @var{num}:@var{den}, where @var{num} and
7548 @var{den} are the numerator and denominator of the aspect ratio. If
7549 the parameter is not specified, it is assumed the value "0".
7550 In case the form "@var{num}:@var{den}" is used, the @code{:} character
7554 Set the maximum integer value to use for expressing numerator and
7555 denominator when reducing the expressed aspect ratio to a rational.
7556 Default value is @code{100}.
7560 The parameter @var{sar} is an expression containing
7561 the following constants:
7565 These are approximated values for the mathematical constants e
7566 (Euler's number), pi (Greek pi), and phi (the golden ratio).
7569 The input width and height.
7572 These are the same as @var{w} / @var{h}.
7575 The input sample aspect ratio.
7578 The input display aspect ratio. It is the same as
7579 (@var{w} / @var{h}) * @var{sar}.
7582 Horizontal and vertical chroma subsample values. For example, for the
7583 pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
7586 @subsection Examples
7591 To change the display aspect ratio to 16:9, specify one of the following:
7599 To change the sample aspect ratio to 10:11, specify:
7605 To set a display aspect ratio of 16:9, and specify a maximum integer value of
7606 1000 in the aspect ratio reduction, use the command:
7608 setdar=ratio=16/9:max=1000
7616 Force field for the output video frame.
7618 The @code{setfield} filter marks the interlace type field for the
7619 output frames. It does not change the input frame, but only sets the
7620 corresponding property, which affects how the frame is treated by
7621 following filters (e.g. @code{fieldorder} or @code{yadif}).
7623 The filter accepts the following options:
7628 Available values are:
7632 Keep the same field property.
7635 Mark the frame as bottom-field-first.
7638 Mark the frame as top-field-first.
7641 Mark the frame as progressive.
7647 Show a line containing various information for each input video frame.
7648 The input video is not modified.
7650 The shown line contains a sequence of key/value pairs of the form
7651 @var{key}:@var{value}.
7653 The following values are shown in the output:
7657 The (sequential) number of the input frame, starting from 0.
7660 The Presentation TimeStamp of the input frame, expressed as a number of
7661 time base units. The time base unit depends on the filter input pad.
7664 The Presentation TimeStamp of the input frame, expressed as a number of
7668 The position of the frame in the input stream, or -1 if this information is
7669 unavailable and/or meaningless (for example in case of synthetic video).
7672 The pixel format name.
7675 The sample aspect ratio of the input frame, expressed in the form
7676 @var{num}/@var{den}.
7679 The size of the input frame. For the syntax of this option, check the "Video size"
7680 section in the ffmpeg-utils manual.
7683 The type of interlaced mode ("P" for "progressive", "T" for top field first, "B"
7684 for bottom field first).
7687 This is 1 if the frame is a key frame, 0 otherwise.
7690 The picture type of the input frame ("I" for an I-frame, "P" for a
7691 P-frame, "B" for a B-frame, or "?" for an unknown type).
7692 Also refer to the documentation of the @code{AVPictureType} enum and of
7693 the @code{av_get_picture_type_char} function defined in
7694 @file{libavutil/avutil.h}.
7697 The Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame.
7699 @item plane_checksum
7700 The Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
7701 expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]".
7704 @section shuffleplanes
7706 Reorder and/or duplicate video planes.
7708 It accepts the following parameters:
7713 The index of the input plane to be used as the first output plane.
7716 The index of the input plane to be used as the second output plane.
7719 The index of the input plane to be used as the third output plane.
7722 The index of the input plane to be used as the fourth output plane.
7726 The first plane has the index 0. The default is to keep the input unchanged.
7728 Swap the second and third planes of the input:
7730 ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT
7733 @section signalstats
7734 Evaluate various visual metrics that assist in determining issues associated
7735 with the digitization of analog video media.
7737 By default the filter will log these metadata values:
7741 Display the minimal Y value contained within the input frame. Expressed in
7745 Display the Y value at the 10% percentile within the input frame. Expressed in
7749 Display the average Y value within the input frame. Expressed in range of
7753 Display the Y value at the 90% percentile within the input frame. Expressed in
7757 Display the maximum Y value contained within the input frame. Expressed in
7761 Display the minimal U value contained within the input frame. Expressed in
7765 Display the U value at the 10% percentile within the input frame. Expressed in
7769 Display the average U value within the input frame. Expressed in range of
7773 Display the U value at the 90% percentile within the input frame. Expressed in
7777 Display the maximum U value contained within the input frame. Expressed in
7781 Display the minimal V value contained within the input frame. Expressed in
7785 Display the V value at the 10% percentile within the input frame. Expressed in
7789 Display the average V value within the input frame. Expressed in range of
7793 Display the V value at the 90% percentile within the input frame. Expressed in
7797 Display the maximum V value contained within the input frame. Expressed in
7801 Display the minimal saturation value contained within the input frame.
7802 Expressed in range of [0-~181.02].
7805 Display the saturation value at the 10% percentile within the input frame.
7806 Expressed in range of [0-~181.02].
7809 Display the average saturation value within the input frame. Expressed in range
7813 Display the saturation value at the 90% percentile within the input frame.
7814 Expressed in range of [0-~181.02].
7817 Display the maximum saturation value contained within the input frame.
7818 Expressed in range of [0-~181.02].
7821 Display the median value for hue within the input frame. Expressed in range of
7825 Display the average value for hue within the input frame. Expressed in range of
7829 Display the average of sample value difference between all values of the Y
7830 plane in the current frame and corresponding values of the previous input frame.
7831 Expressed in range of [0-255].
7834 Display the average of sample value difference between all values of the U
7835 plane in the current frame and corresponding values of the previous input frame.
7836 Expressed in range of [0-255].
7839 Display the average of sample value difference between all values of the V
7840 plane in the current frame and corresponding values of the previous input frame.
7841 Expressed in range of [0-255].
7844 The filter accepts the following options:
7850 @option{stat} specify an additional form of image analysis.
7851 @option{out} output video with the specified type of pixel highlighted.
7853 Both options accept the following values:
7857 Identify @var{temporal outliers} pixels. A @var{temporal outlier} is a pixel
7858 unlike the neighboring pixels of the same field. Examples of temporal outliers
7859 include the results of video dropouts, head clogs, or tape tracking issues.
7862 Identify @var{vertical line repetition}. Vertical line repetition includes
7863 similar rows of pixels within a frame. In born-digital video vertical line
7864 repetition is common, but this pattern is uncommon in video digitized from an
7865 analog source. When it occurs in video that results from the digitization of an
7866 analog source it can indicate concealment from a dropout compensator.
7869 Identify pixels that fall outside of legal broadcast range.
7873 Set the highlight color for the @option{out} option. The default color is
7877 @subsection Examples
7881 Output data of various video metrics:
7883 ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng" -show_frames
7887 Output specific data about the minimum and maximum values of the Y plane per frame:
7889 ffprobe -f lavfi movie=example.mov,signalstats -show_entries frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN
7893 Playback video while highlighting pixels that are outside of broadcast range in red.
7895 ffplay example.mov -vf signalstats="out=brng:color=red"
7899 Playback video with signalstats metadata drawn over the frame.
7901 ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt
7904 The contents of signalstat_drawtext.txt used in the command are:
7907 Y (%@{metadata:lavfi.signalstats.YMIN@}-%@{metadata:lavfi.signalstats.YMAX@})
7908 U (%@{metadata:lavfi.signalstats.UMIN@}-%@{metadata:lavfi.signalstats.UMAX@})
7909 V (%@{metadata:lavfi.signalstats.VMIN@}-%@{metadata:lavfi.signalstats.VMAX@})
7910 saturation maximum: %@{metadata:lavfi.signalstats.SATMAX@}
7918 Blur the input video without impacting the outlines.
7920 It accepts the following options:
7923 @item luma_radius, lr
7924 Set the luma radius. The option value must be a float number in
7925 the range [0.1,5.0] that specifies the variance of the gaussian filter
7926 used to blur the image (slower if larger). Default value is 1.0.
7928 @item luma_strength, ls
7929 Set the luma strength. The option value must be a float number
7930 in the range [-1.0,1.0] that configures the blurring. A value included
7931 in [0.0,1.0] will blur the image whereas a value included in
7932 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7934 @item luma_threshold, lt
7935 Set the luma threshold used as a coefficient to determine
7936 whether a pixel should be blurred or not. The option value must be an
7937 integer in the range [-30,30]. A value of 0 will filter all the image,
7938 a value included in [0,30] will filter flat areas and a value included
7939 in [-30,0] will filter edges. Default value is 0.
7941 @item chroma_radius, cr
7942 Set the chroma radius. The option value must be a float number in
7943 the range [0.1,5.0] that specifies the variance of the gaussian filter
7944 used to blur the image (slower if larger). Default value is 1.0.
7946 @item chroma_strength, cs
7947 Set the chroma strength. The option value must be a float number
7948 in the range [-1.0,1.0] that configures the blurring. A value included
7949 in [0.0,1.0] will blur the image whereas a value included in
7950 [-1.0,0.0] will sharpen the image. Default value is 1.0.
7952 @item chroma_threshold, ct
7953 Set the chroma threshold used as a coefficient to determine
7954 whether a pixel should be blurred or not. The option value must be an
7955 integer in the range [-30,30]. A value of 0 will filter all the image,
7956 a value included in [0,30] will filter flat areas and a value included
7957 in [-30,0] will filter edges. Default value is 0.
7960 If a chroma option is not explicitly set, the corresponding luma value
7965 Convert between different stereoscopic image formats.
7967 The filters accept the following options:
7971 Set stereoscopic image format of input.
7973 Available values for input image formats are:
7976 side by side parallel (left eye left, right eye right)
7979 side by side crosseye (right eye left, left eye right)
7982 side by side parallel with half width resolution
7983 (left eye left, right eye right)
7986 side by side crosseye with half width resolution
7987 (right eye left, left eye right)
7990 above-below (left eye above, right eye below)
7993 above-below (right eye above, left eye below)
7996 above-below with half height resolution
7997 (left eye above, right eye below)
8000 above-below with half height resolution
8001 (right eye above, left eye below)
8004 alternating frames (left eye first, right eye second)
8007 alternating frames (right eye first, left eye second)
8009 Default value is @samp{sbsl}.
8013 Set stereoscopic image format of output.
8015 Available values for output image formats are all the input formats as well as:
8018 anaglyph red/blue gray
8019 (red filter on left eye, blue filter on right eye)
8022 anaglyph red/green gray
8023 (red filter on left eye, green filter on right eye)
8026 anaglyph red/cyan gray
8027 (red filter on left eye, cyan filter on right eye)
8030 anaglyph red/cyan half colored
8031 (red filter on left eye, cyan filter on right eye)
8034 anaglyph red/cyan color
8035 (red filter on left eye, cyan filter on right eye)
8038 anaglyph red/cyan color optimized with the least squares projection of dubois
8039 (red filter on left eye, cyan filter on right eye)
8042 anaglyph green/magenta gray
8043 (green filter on left eye, magenta filter on right eye)
8046 anaglyph green/magenta half colored
8047 (green filter on left eye, magenta filter on right eye)
8050 anaglyph green/magenta colored
8051 (green filter on left eye, magenta filter on right eye)
8054 anaglyph green/magenta color optimized with the least squares projection of dubois
8055 (green filter on left eye, magenta filter on right eye)
8058 anaglyph yellow/blue gray
8059 (yellow filter on left eye, blue filter on right eye)
8062 anaglyph yellow/blue half colored
8063 (yellow filter on left eye, blue filter on right eye)
8066 anaglyph yellow/blue colored
8067 (yellow filter on left eye, blue filter on right eye)
8070 anaglyph yellow/blue color optimized with the least squares projection of dubois
8071 (yellow filter on left eye, blue filter on right eye)
8074 interleaved rows (left eye has top row, right eye starts on next row)
8077 interleaved rows (right eye has top row, left eye starts on next row)
8080 mono output (left eye only)
8083 mono output (right eye only)
8086 Default value is @samp{arcd}.
8089 @subsection Examples
8093 Convert input video from side by side parallel to anaglyph yellow/blue dubois:
8099 Convert input video from above bellow (left eye above, right eye below) to side by side crosseye.
8107 Apply a simple postprocessing filter that compresses and decompresses the image
8108 at several (or - in the case of @option{quality} level @code{6} - all) shifts
8109 and average the results.
8111 The filter accepts the following options:
8115 Set quality. This option defines the number of levels for averaging. It accepts
8116 an integer in the range 0-6. If set to @code{0}, the filter will have no
8117 effect. A value of @code{6} means the higher quality. For each increment of
8118 that value the speed drops by a factor of approximately 2. Default value is
8122 Force a constant quantization parameter. If not set, the filter will use the QP
8123 from the video stream (if available).
8126 Set thresholding mode. Available modes are:
8130 Set hard thresholding (default).
8132 Set soft thresholding (better de-ringing effect, but likely blurrier).
8136 Enable the use of the QP from the B-Frames if set to @code{1}. Using this
8137 option may cause flicker since the B-Frames have often larger QP. Default is
8138 @code{0} (not enabled).
8144 Draw subtitles on top of input video using the libass library.
8146 To enable compilation of this filter you need to configure FFmpeg with
8147 @code{--enable-libass}. This filter also requires a build with libavcodec and
8148 libavformat to convert the passed subtitles file to ASS (Advanced Substation
8149 Alpha) subtitles format.
8151 The filter accepts the following options:
8155 Set the filename of the subtitle file to read. It must be specified.
8158 Specify the size of the original video, the video for which the ASS file
8159 was composed. For the syntax of this option, check the "Video size" section in
8160 the ffmpeg-utils manual. Due to a misdesign in ASS aspect ratio arithmetic,
8161 this is necessary to correctly scale the fonts if the aspect ratio has been
8165 Set subtitles input character encoding. @code{subtitles} filter only. Only
8166 useful if not UTF-8.
8168 @item stream_index, si
8169 Set subtitles stream index. @code{subtitles} filter only.
8172 If the first key is not specified, it is assumed that the first value
8173 specifies the @option{filename}.
8175 For example, to render the file @file{sub.srt} on top of the input
8176 video, use the command:
8181 which is equivalent to:
8183 subtitles=filename=sub.srt
8186 To render the default subtitles stream from file @file{video.mkv}, use:
8191 To render the second subtitles stream from that file, use:
8193 subtitles=video.mkv:si=1
8198 Scale the input by 2x and smooth using the Super2xSaI (Scale and
8199 Interpolate) pixel art scaling algorithm.
8201 Useful for enlarging pixel art images without reducing sharpness.
8208 Apply telecine process to the video.
8210 This filter accepts the following options:
8219 The default value is @code{top}.
8223 A string of numbers representing the pulldown pattern you wish to apply.
8224 The default value is @code{23}.
8228 Some typical patterns:
8233 24p: 2332 (preferred)
8240 24p: 222222222223 ("Euro pulldown")
8246 Select the most representative frame in a given sequence of consecutive frames.
8248 The filter accepts the following options:
8252 Set the frames batch size to analyze; in a set of @var{n} frames, the filter
8253 will pick one of them, and then handle the next batch of @var{n} frames until
8254 the end. Default is @code{100}.
8257 Since the filter keeps track of the whole frames sequence, a bigger @var{n}
8258 value will result in a higher memory usage, so a high value is not recommended.
8260 @subsection Examples
8264 Extract one picture each 50 frames:
8270 Complete example of a thumbnail creation with @command{ffmpeg}:
8272 ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
8278 Tile several successive frames together.
8280 The filter accepts the following options:
8285 Set the grid size (i.e. the number of lines and columns). For the syntax of
8286 this option, check the "Video size" section in the ffmpeg-utils manual.
8289 Set the maximum number of frames to render in the given area. It must be less
8290 than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all
8291 the area will be used.
8294 Set the outer border margin in pixels.
8297 Set the inner border thickness (i.e. the number of pixels between frames). For
8298 more advanced padding options (such as having different values for the edges),
8299 refer to the pad video filter.
8302 Specify the color of the unused areaFor the syntax of this option, check the
8303 "Color" section in the ffmpeg-utils manual. The default value of @var{color}
8307 @subsection Examples
8311 Produce 8x8 PNG tiles of all keyframes (@option{-skip_frame nokey}) in a movie:
8313 ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
8315 The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
8316 duplicating each output frame to accommodate the originally detected frame
8320 Display @code{5} pictures in an area of @code{3x2} frames,
8321 with @code{7} pixels between them, and @code{2} pixels of initial margin, using
8322 mixed flat and named options:
8324 tile=3x2:nb_frames=5:padding=7:margin=2
8330 Perform various types of temporal field interlacing.
8332 Frames are counted starting from 1, so the first input frame is
8335 The filter accepts the following options:
8340 Specify the mode of the interlacing. This option can also be specified
8341 as a value alone. See below for a list of values for this option.
8343 Available values are:
8347 Move odd frames into the upper field, even into the lower field,
8348 generating a double height frame at half frame rate.
8351 Only output even frames, odd frames are dropped, generating a frame with
8352 unchanged height at half frame rate.
8355 Only output odd frames, even frames are dropped, generating a frame with
8356 unchanged height at half frame rate.
8359 Expand each frame to full height, but pad alternate lines with black,
8360 generating a frame with double height at the same input frame rate.
8362 @item interleave_top, 4
8363 Interleave the upper field from odd frames with the lower field from
8364 even frames, generating a frame with unchanged height at half frame rate.
8366 @item interleave_bottom, 5
8367 Interleave the lower field from odd frames with the upper field from
8368 even frames, generating a frame with unchanged height at half frame rate.
8370 @item interlacex2, 6
8371 Double frame rate with unchanged height. Frames are inserted each
8372 containing the second temporal field from the previous input frame and
8373 the first temporal field from the next input frame. This mode relies on
8374 the top_field_first flag. Useful for interlaced video displays with no
8375 field synchronisation.
8378 Numeric values are deprecated but are accepted for backward
8379 compatibility reasons.
8381 Default mode is @code{merge}.
8384 Specify flags influencing the filter process.
8386 Available value for @var{flags} is:
8389 @item low_pass_filter, vlfp
8390 Enable vertical low-pass filtering in the filter.
8391 Vertical low-pass filtering is required when creating an interlaced
8392 destination from a progressive source which contains high-frequency
8393 vertical detail. Filtering will reduce interlace 'twitter' and Moire
8396 Vertical low-pass filtering can only be enabled for @option{mode}
8397 @var{interleave_top} and @var{interleave_bottom}.
8404 Transpose rows with columns in the input video and optionally flip it.
8406 It accepts the following parameters:
8411 Specify the transposition direction.
8413 Can assume the following values:
8415 @item 0, 4, cclock_flip
8416 Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
8424 Rotate by 90 degrees clockwise, that is:
8432 Rotate by 90 degrees counterclockwise, that is:
8439 @item 3, 7, clock_flip
8440 Rotate by 90 degrees clockwise and vertically flip, that is:
8448 For values between 4-7, the transposition is only done if the input
8449 video geometry is portrait and not landscape. These values are
8450 deprecated, the @code{passthrough} option should be used instead.
8452 Numerical values are deprecated, and should be dropped in favor of
8456 Do not apply the transposition if the input geometry matches the one
8457 specified by the specified value. It accepts the following values:
8460 Always apply transposition.
8462 Preserve portrait geometry (when @var{height} >= @var{width}).
8464 Preserve landscape geometry (when @var{width} >= @var{height}).
8467 Default value is @code{none}.
8470 For example to rotate by 90 degrees clockwise and preserve portrait
8473 transpose=dir=1:passthrough=portrait
8476 The command above can also be specified as:
8478 transpose=1:portrait
8482 Trim the input so that the output contains one continuous subpart of the input.
8484 It accepts the following parameters:
8487 Specify the time of the start of the kept section, i.e. the frame with the
8488 timestamp @var{start} will be the first frame in the output.
8491 Specify the time of the first frame that will be dropped, i.e. the frame
8492 immediately preceding the one with the timestamp @var{end} will be the last
8493 frame in the output.
8496 This is the same as @var{start}, except this option sets the start timestamp
8497 in timebase units instead of seconds.
8500 This is the same as @var{end}, except this option sets the end timestamp
8501 in timebase units instead of seconds.
8504 The maximum duration of the output in seconds.
8507 The number of the first frame that should be passed to the output.
8510 The number of the first frame that should be dropped.
8513 @option{start}, @option{end}, @option{duration} are expressed as time
8514 duration specifications, check the "Time duration" section in the
8515 ffmpeg-utils manual.
8517 Note that the first two sets of the start/end options and the @option{duration}
8518 option look at the frame timestamp, while the _frame variants simply count the
8519 frames that pass through the filter. Also note that this filter does not modify
8520 the timestamps. If you wish for the output timestamps to start at zero, insert a
8521 setpts filter after the trim filter.
8523 If multiple start or end options are set, this filter tries to be greedy and
8524 keep all the frames that match at least one of the specified constraints. To keep
8525 only the part that matches all the constraints at once, chain multiple trim
8528 The defaults are such that all the input is kept. So it is possible to set e.g.
8529 just the end values to keep everything before the specified time.
8534 Drop everything except the second minute of input:
8536 ffmpeg -i INPUT -vf trim=60:120
8540 Keep only the first second:
8542 ffmpeg -i INPUT -vf trim=duration=1
8550 Sharpen or blur the input video.
8552 It accepts the following parameters:
8555 @item luma_msize_x, lx
8556 Set the luma matrix horizontal size. It must be an odd integer between
8557 3 and 63. The default value is 5.
8559 @item luma_msize_y, ly
8560 Set the luma matrix vertical size. It must be an odd integer between 3
8561 and 63. The default value is 5.
8563 @item luma_amount, la
8564 Set the luma effect strength. It must be a floating point number, reasonable
8565 values lay between -1.5 and 1.5.
8567 Negative values will blur the input video, while positive values will
8568 sharpen it, a value of zero will disable the effect.
8570 Default value is 1.0.
8572 @item chroma_msize_x, cx
8573 Set the chroma matrix horizontal size. It must be an odd integer
8574 between 3 and 63. The default value is 5.
8576 @item chroma_msize_y, cy
8577 Set the chroma matrix vertical size. It must be an odd integer
8578 between 3 and 63. The default value is 5.
8580 @item chroma_amount, ca
8581 Set the chroma effect strength. It must be a floating point number, reasonable
8582 values lay between -1.5 and 1.5.
8584 Negative values will blur the input video, while positive values will
8585 sharpen it, a value of zero will disable the effect.
8587 Default value is 0.0.
8590 If set to 1, specify using OpenCL capabilities, only available if
8591 FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
8595 All parameters are optional and default to the equivalent of the
8596 string '5:5:1.0:5:5:0.0'.
8598 @subsection Examples
8602 Apply strong luma sharpen effect:
8604 unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5
8608 Apply a strong blur of both luma and chroma parameters:
8610 unsharp=7:7:-2:7:7:-2
8614 @anchor{vidstabdetect}
8615 @section vidstabdetect
8617 Analyze video stabilization/deshaking. Perform pass 1 of 2, see
8618 @ref{vidstabtransform} for pass 2.
8620 This filter generates a file with relative translation and rotation
8621 transform information about subsequent frames, which is then used by
8622 the @ref{vidstabtransform} filter.
8624 To enable compilation of this filter you need to configure FFmpeg with
8625 @code{--enable-libvidstab}.
8627 This filter accepts the following options:
8631 Set the path to the file used to write the transforms information.
8632 Default value is @file{transforms.trf}.
8635 Set how shaky the video is and how quick the camera is. It accepts an
8636 integer in the range 1-10, a value of 1 means little shakiness, a
8637 value of 10 means strong shakiness. Default value is 5.
8640 Set the accuracy of the detection process. It must be a value in the
8641 range 1-15. A value of 1 means low accuracy, a value of 15 means high
8642 accuracy. Default value is 15.
8645 Set stepsize of the search process. The region around minimum is
8646 scanned with 1 pixel resolution. Default value is 6.
8649 Set minimum contrast. Below this value a local measurement field is
8650 discarded. Must be a floating point value in the range 0-1. Default
8654 Set reference frame number for tripod mode.
8656 If enabled, the motion of the frames is compared to a reference frame
8657 in the filtered stream, identified by the specified number. The idea
8658 is to compensate all movements in a more-or-less static scene and keep
8659 the camera view absolutely still.
8661 If set to 0, it is disabled. The frames are counted starting from 1.
8664 Show fields and transforms in the resulting frames. It accepts an
8665 integer in the range 0-2. Default value is 0, which disables any
8669 @subsection Examples
8679 Analyze strongly shaky movie and put the results in file
8680 @file{mytransforms.trf}:
8682 vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"
8686 Visualize the result of internal transformations in the resulting
8689 vidstabdetect=show=1
8693 Analyze a video with medium shakiness using @command{ffmpeg}:
8695 ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi
8699 @anchor{vidstabtransform}
8700 @section vidstabtransform
8702 Video stabilization/deshaking: pass 2 of 2,
8703 see @ref{vidstabdetect} for pass 1.
8705 Read a file with transform information for each frame and
8706 apply/compensate them. Together with the @ref{vidstabdetect}
8707 filter this can be used to deshake videos. See also
8708 @url{http://public.hronopik.de/vid.stab}. It is important to also use
8709 the unsharp filter, see below.
8711 To enable compilation of this filter you need to configure FFmpeg with
8712 @code{--enable-libvidstab}.
8718 Set path to the file used to read the transforms. Default value is
8719 @file{transforms.trf}).
8722 Set the number of frames (value*2 + 1) used for lowpass filtering the
8723 camera movements. Default value is 10.
8725 For example a number of 10 means that 21 frames are used (10 in the
8726 past and 10 in the future) to smoothen the motion in the video. A
8727 larger values leads to a smoother video, but limits the acceleration
8728 of the camera (pan/tilt movements). 0 is a special case where a
8729 static camera is simulated.
8732 Set the camera path optimization algorithm.
8734 Accepted values are:
8737 gaussian kernel low-pass filter on camera motion (default)
8739 averaging on transformations
8743 Set maximal number of pixels to translate frames. Default value is -1,
8747 Set maximal angle in radians (degree*PI/180) to rotate frames. Default
8748 value is -1, meaning no limit.
8751 Specify how to deal with borders that may be visible due to movement
8754 Available values are:
8757 keep image information from previous frame (default)
8759 fill the border black
8763 Invert transforms if set to 1. Default value is 0.
8766 Consider transforms as relative to previsou frame if set to 1,
8767 absolute if set to 0. Default value is 0.
8770 Set percentage to zoom. A positive value will result in a zoom-in
8771 effect, a negative value in a zoom-out effect. Default value is 0 (no
8775 Set optimal zooming to avoid borders.
8777 Accepted values are:
8782 optimal static zoom value is determined (only very strong movements
8783 will lead to visible borders) (default)
8785 optimal adaptive zoom value is determined (no borders will be
8786 visible), see @option{zoomspeed}
8789 Note that the value given at zoom is added to the one calculated here.
8792 Set percent to zoom maximally each frame (enabled when
8793 @option{optzoom} is set to 2). Range is from 0 to 5, default value is
8797 Specify type of interpolation.
8799 Available values are:
8804 linear only horizontal
8806 linear in both directions (default)
8808 cubic in both directions (slow)
8812 Enable virtual tripod mode if set to 1, which is equivalent to
8813 @code{relative=0:smoothing=0}. Default value is 0.
8815 Use also @code{tripod} option of @ref{vidstabdetect}.
8818 Increase log verbosity if set to 1. Also the detected global motions
8819 are written to the temporary file @file{global_motions.trf}. Default
8823 @subsection Examples
8827 Use @command{ffmpeg} for a typical stabilization with default values:
8829 ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg
8832 Note the use of the unsharp filter which is always recommended.
8835 Zoom in a bit more and load transform data from a given file:
8837 vidstabtransform=zoom=5:input="mytransforms.trf"
8841 Smoothen the video even more:
8843 vidstabtransform=smoothing=30
8849 Flip the input video vertically.
8851 For example, to vertically flip a video with @command{ffmpeg}:
8853 ffmpeg -i in.avi -vf "vflip" out.avi
8859 Make or reverse a natural vignetting effect.
8861 The filter accepts the following options:
8865 Set lens angle expression as a number of radians.
8867 The value is clipped in the @code{[0,PI/2]} range.
8869 Default value: @code{"PI/5"}
8873 Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"}
8877 Set forward/backward mode.
8879 Available modes are:
8882 The larger the distance from the central point, the darker the image becomes.
8885 The larger the distance from the central point, the brighter the image becomes.
8886 This can be used to reverse a vignette effect, though there is no automatic
8887 detection to extract the lens @option{angle} and other settings (yet). It can
8888 also be used to create a burning effect.
8891 Default value is @samp{forward}.
8894 Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}).
8896 It accepts the following values:
8899 Evaluate expressions only once during the filter initialization.
8902 Evaluate expressions for each incoming frame. This is way slower than the
8903 @samp{init} mode since it requires all the scalers to be re-computed, but it
8904 allows advanced dynamic expressions.
8907 Default value is @samp{init}.
8910 Set dithering to reduce the circular banding effects. Default is @code{1}
8914 Set vignette aspect. This setting allows one to adjust the shape of the vignette.
8915 Setting this value to the SAR of the input will make a rectangular vignetting
8916 following the dimensions of the video.
8918 Default is @code{1/1}.
8921 @subsection Expressions
8923 The @option{alpha}, @option{x0} and @option{y0} expressions can contain the
8924 following parameters.
8929 input width and height
8932 the number of input frame, starting from 0
8935 the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in
8936 @var{TB} units, NAN if undefined
8939 frame rate of the input video, NAN if the input frame rate is unknown
8942 the PTS (Presentation TimeStamp) of the filtered video frame,
8943 expressed in seconds, NAN if undefined
8946 time base of the input video
8950 @subsection Examples
8954 Apply simple strong vignetting effect:
8960 Make a flickering vignetting:
8962 vignette='PI/4+random(1)*PI/50':eval=frame
8969 Deinterlace the input video ("w3fdif" stands for "Weston 3 Field
8970 Deinterlacing Filter").
8972 Based on the process described by Martin Weston for BBC R&D, and
8973 implemented based on the de-interlace algorithm written by Jim
8974 Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter
8975 uses filter coefficients calculated by BBC R&D.
8977 There are two sets of filter coefficients, so called "simple":
8978 and "complex". Which set of filter coefficients is used can
8979 be set by passing an optional parameter:
8983 Set the interlacing filter coefficients. Accepts one of the following values:
8987 Simple filter coefficient set.
8989 More-complex filter coefficient set.
8991 Default value is @samp{complex}.
8994 Specify which frames to deinterlace. Accept one of the following values:
8998 Deinterlace all frames,
9000 Only deinterlace frames marked as interlaced.
9003 Default value is @samp{all}.
9009 Deinterlace the input video ("yadif" means "yet another deinterlacing
9012 It accepts the following parameters:
9018 The interlacing mode to adopt. It accepts one of the following values:
9022 Output one frame for each frame.
9024 Output one frame for each field.
9025 @item 2, send_frame_nospatial
9026 Like @code{send_frame}, but it skips the spatial interlacing check.
9027 @item 3, send_field_nospatial
9028 Like @code{send_field}, but it skips the spatial interlacing check.
9031 The default value is @code{send_frame}.
9034 The picture field parity assumed for the input interlaced video. It accepts one
9035 of the following values:
9039 Assume the top field is first.
9041 Assume the bottom field is first.
9043 Enable automatic detection of field parity.
9046 The default value is @code{auto}.
9047 If the interlacing is unknown or the decoder does not export this information,
9048 top field first will be assumed.
9051 Specify which frames to deinterlace. Accept one of the following
9056 Deinterlace all frames.
9058 Only deinterlace frames marked as interlaced.
9061 The default value is @code{all}.
9066 Apply Zoom & Pan effect.
9068 This filter accepts the following options:
9072 Set the zoom expression. Default is 1.
9076 Set the x and y expression. Default is 0.
9079 Set the duration expression in number of frames.
9080 This sets for how many number of frames effect will last for
9084 Set the output image size, default is 'hd720'.
9087 Each expression can contain the following constants:
9110 Last calculated 'x' and 'y' position from 'x' and 'y' expression
9111 for current input frame.
9115 'x' and 'y' of last output frame of previous input frame or 0 when there was
9116 not yet such frame (first input frame).
9119 Last calculated zoom from 'z' expression for current input frame.
9122 Last calculated zoom of last output frame of previous input frame.
9125 Number of output frames for current input frame. Calculated from 'd' expression
9126 for each input frame.
9129 number of output frames created for previous input frame
9132 Rational number: input width / input height
9138 display aspect ratio
9142 @subsection Examples
9146 Zoom-in up to 1.5 and pan at same time to some spot near center of picture:
9148 zoompan=z='min(zoom+0.0015,1.5)':d=700:x='if(gte(zoom,1.5),x,x+1/a)':y='if(gte(zoom,1.5),y,y+1)':s=640x360
9152 @c man end VIDEO FILTERS
9154 @chapter Video Sources
9155 @c man begin VIDEO SOURCES
9157 Below is a description of the currently available video sources.
9161 Buffer video frames, and make them available to the filter chain.
9163 This source is mainly intended for a programmatic use, in particular
9164 through the interface defined in @file{libavfilter/vsrc_buffer.h}.
9166 It accepts the following parameters:
9171 Specify the size (width and height) of the buffered video frames. For the
9172 syntax of this option, check the "Video size" section in the ffmpeg-utils
9176 The input video width.
9179 The input video height.
9182 A string representing the pixel format of the buffered video frames.
9183 It may be a number corresponding to a pixel format, or a pixel format
9187 Specify the timebase assumed by the timestamps of the buffered frames.
9190 Specify the frame rate expected for the video stream.
9192 @item pixel_aspect, sar
9193 The sample (pixel) aspect ratio of the input video.
9196 Specify the optional parameters to be used for the scale filter which
9197 is automatically inserted when an input change is detected in the
9198 input size or format.
9203 buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1
9206 will instruct the source to accept video frames with size 320x240 and
9207 with format "yuv410p", assuming 1/24 as the timestamps timebase and
9208 square pixels (1:1 sample aspect ratio).
9209 Since the pixel format with name "yuv410p" corresponds to the number 6
9210 (check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
9211 this example corresponds to:
9213 buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
9216 Alternatively, the options can be specified as a flat string, but this
9217 syntax is deprecated:
9219 @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}]
9223 Create a pattern generated by an elementary cellular automaton.
9225 The initial state of the cellular automaton can be defined through the
9226 @option{filename}, and @option{pattern} options. If such options are
9227 not specified an initial state is created randomly.
9229 At each new frame a new row in the video is filled with the result of
9230 the cellular automaton next generation. The behavior when the whole
9231 frame is filled is defined by the @option{scroll} option.
9233 This source accepts the following options:
9237 Read the initial cellular automaton state, i.e. the starting row, from
9239 In the file, each non-whitespace character is considered an alive
9240 cell, a newline will terminate the row, and further characters in the
9241 file will be ignored.
9244 Read the initial cellular automaton state, i.e. the starting row, from
9245 the specified string.
9247 Each non-whitespace character in the string is considered an alive
9248 cell, a newline will terminate the row, and further characters in the
9249 string will be ignored.
9252 Set the video rate, that is the number of frames generated per second.
9255 @item random_fill_ratio, ratio
9256 Set the random fill ratio for the initial cellular automaton row. It
9257 is a floating point number value ranging from 0 to 1, defaults to
9260 This option is ignored when a file or a pattern is specified.
9262 @item random_seed, seed
9263 Set the seed for filling randomly the initial row, must be an integer
9264 included between 0 and UINT32_MAX. If not specified, or if explicitly
9265 set to -1, the filter will try to use a good random seed on a best
9269 Set the cellular automaton rule, it is a number ranging from 0 to 255.
9270 Default value is 110.
9273 Set the size of the output video. For the syntax of this option, check
9274 the "Video size" section in the ffmpeg-utils manual.
9276 If @option{filename} or @option{pattern} is specified, the size is set
9277 by default to the width of the specified initial state row, and the
9278 height is set to @var{width} * PHI.
9280 If @option{size} is set, it must contain the width of the specified
9281 pattern string, and the specified pattern will be centered in the
9284 If a filename or a pattern string is not specified, the size value
9285 defaults to "320x518" (used for a randomly generated initial state).
9288 If set to 1, scroll the output upward when all the rows in the output
9289 have been already filled. If set to 0, the new generated row will be
9290 written over the top row just after the bottom row is filled.
9293 @item start_full, full
9294 If set to 1, completely fill the output with generated rows before
9295 outputting the first frame.
9296 This is the default behavior, for disabling set the value to 0.
9299 If set to 1, stitch the left and right row edges together.
9300 This is the default behavior, for disabling set the value to 0.
9303 @subsection Examples
9307 Read the initial state from @file{pattern}, and specify an output of
9310 cellauto=f=pattern:s=200x400
9314 Generate a random initial row with a width of 200 cells, with a fill
9317 cellauto=ratio=2/3:s=200x200
9321 Create a pattern generated by rule 18 starting by a single alive cell
9322 centered on an initial row with width 100:
9324 cellauto=p=@@:s=100x400:full=0:rule=18
9328 Specify a more elaborated initial pattern:
9330 cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
9337 Generate a Mandelbrot set fractal, and progressively zoom towards the
9338 point specified with @var{start_x} and @var{start_y}.
9340 This source accepts the following options:
9345 Set the terminal pts value. Default value is 400.
9348 Set the terminal scale value.
9349 Must be a floating point value. Default value is 0.3.
9352 Set the inner coloring mode, that is the algorithm used to draw the
9353 Mandelbrot fractal internal region.
9355 It shall assume one of the following values:
9360 Show time until convergence.
9362 Set color based on point closest to the origin of the iterations.
9367 Default value is @var{mincol}.
9370 Set the bailout value. Default value is 10.0.
9373 Set the maximum of iterations performed by the rendering
9374 algorithm. Default value is 7189.
9377 Set outer coloring mode.
9378 It shall assume one of following values:
9380 @item iteration_count
9381 Set iteration cound mode.
9382 @item normalized_iteration_count
9383 set normalized iteration count mode.
9385 Default value is @var{normalized_iteration_count}.
9388 Set frame rate, expressed as number of frames per second. Default
9392 Set frame size. For the syntax of this option, check the "Video
9393 size" section in the ffmpeg-utils manual. Default value is "640x480".
9396 Set the initial scale value. Default value is 3.0.
9399 Set the initial x position. Must be a floating point value between
9400 -100 and 100. Default value is -0.743643887037158704752191506114774.
9403 Set the initial y position. Must be a floating point value between
9404 -100 and 100. Default value is -0.131825904205311970493132056385139.
9409 Generate various test patterns, as generated by the MPlayer test filter.
9411 The size of the generated video is fixed, and is 256x256.
9412 This source is useful in particular for testing encoding features.
9414 This source accepts the following options:
9419 Specify the frame rate of the sourced video, as the number of frames
9420 generated per second. It has to be a string in the format
9421 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9422 number or a valid video frame rate abbreviation. The default value is
9426 Set the video duration of the sourced video. The accepted syntax is:
9431 See also the function @code{av_parse_time()}.
9433 If not specified, or the expressed duration is negative, the video is
9434 supposed to be generated forever.
9438 Set the number or the name of the test to perform. Supported tests are:
9454 Default value is "all", which will cycle through the list of all tests.
9462 will generate a "dc_luma" test pattern.
9466 Provide a frei0r source.
9468 To enable compilation of this filter you need to install the frei0r
9469 header and configure FFmpeg with @code{--enable-frei0r}.
9471 This source accepts the following parameters:
9476 The size of the video to generate. For the syntax of this option, check the
9477 "Video size" section in the ffmpeg-utils manual.
9480 The framerate of the generated video. It may be a string of the form
9481 @var{num}/@var{den} or a frame rate abbreviation.
9484 The name to the frei0r source to load. For more information regarding frei0r and
9485 how to set the parameters, read the @ref{frei0r} section in the video filters
9489 A '|'-separated list of parameters to pass to the frei0r source.
9493 For example, to generate a frei0r partik0l source with size 200x200
9494 and frame rate 10 which is overlayed on the overlay filter main input:
9496 frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay
9501 Generate a life pattern.
9503 This source is based on a generalization of John Conway's life game.
9505 The sourced input represents a life grid, each pixel represents a cell
9506 which can be in one of two possible states, alive or dead. Every cell
9507 interacts with its eight neighbours, which are the cells that are
9508 horizontally, vertically, or diagonally adjacent.
9510 At each interaction the grid evolves according to the adopted rule,
9511 which specifies the number of neighbor alive cells which will make a
9512 cell stay alive or born. The @option{rule} option allows one to specify
9515 This source accepts the following options:
9519 Set the file from which to read the initial grid state. In the file,
9520 each non-whitespace character is considered an alive cell, and newline
9521 is used to delimit the end of each row.
9523 If this option is not specified, the initial grid is generated
9527 Set the video rate, that is the number of frames generated per second.
9530 @item random_fill_ratio, ratio
9531 Set the random fill ratio for the initial random grid. It is a
9532 floating point number value ranging from 0 to 1, defaults to 1/PHI.
9533 It is ignored when a file is specified.
9535 @item random_seed, seed
9536 Set the seed for filling the initial random grid, must be an integer
9537 included between 0 and UINT32_MAX. If not specified, or if explicitly
9538 set to -1, the filter will try to use a good random seed on a best
9544 A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
9545 where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
9546 @var{NS} specifies the number of alive neighbor cells which make a
9547 live cell stay alive, and @var{NB} the number of alive neighbor cells
9548 which make a dead cell to become alive (i.e. to "born").
9549 "s" and "b" can be used in place of "S" and "B", respectively.
9551 Alternatively a rule can be specified by an 18-bits integer. The 9
9552 high order bits are used to encode the next cell state if it is alive
9553 for each number of neighbor alive cells, the low order bits specify
9554 the rule for "borning" new cells. Higher order bits encode for an
9555 higher number of neighbor cells.
9556 For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
9557 rule of 12 and a born rule of 9, which corresponds to "S23/B03".
9559 Default value is "S23/B3", which is the original Conway's game of life
9560 rule, and will keep a cell alive if it has 2 or 3 neighbor alive
9561 cells, and will born a new cell if there are three alive cells around
9565 Set the size of the output video. For the syntax of this option, check the
9566 "Video size" section in the ffmpeg-utils manual.
9568 If @option{filename} is specified, the size is set by default to the
9569 same size of the input file. If @option{size} is set, it must contain
9570 the size specified in the input file, and the initial grid defined in
9571 that file is centered in the larger resulting area.
9573 If a filename is not specified, the size value defaults to "320x240"
9574 (used for a randomly generated initial grid).
9577 If set to 1, stitch the left and right grid edges together, and the
9578 top and bottom edges also. Defaults to 1.
9581 Set cell mold speed. If set, a dead cell will go from @option{death_color} to
9582 @option{mold_color} with a step of @option{mold}. @option{mold} can have a
9583 value from 0 to 255.
9586 Set the color of living (or new born) cells.
9589 Set the color of dead cells. If @option{mold} is set, this is the first color
9590 used to represent a dead cell.
9593 Set mold color, for definitely dead and moldy cells.
9595 For the syntax of these 3 color options, check the "Color" section in the
9596 ffmpeg-utils manual.
9599 @subsection Examples
9603 Read a grid from @file{pattern}, and center it on a grid of size
9606 life=f=pattern:s=300x300
9610 Generate a random grid of size 200x200, with a fill ratio of 2/3:
9612 life=ratio=2/3:s=200x200
9616 Specify a custom rule for evolving a randomly generated grid:
9622 Full example with slow death effect (mold) using @command{ffplay}:
9624 ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
9629 @anchor{haldclutsrc}
9633 @anchor{smptehdbars}
9635 @section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc
9637 The @code{color} source provides an uniformly colored input.
9639 The @code{haldclutsrc} source provides an identity Hald CLUT. See also
9640 @ref{haldclut} filter.
9642 The @code{nullsrc} source returns unprocessed video frames. It is
9643 mainly useful to be employed in analysis / debugging tools, or as the
9644 source for filters which ignore the input data.
9646 The @code{rgbtestsrc} source generates an RGB test pattern useful for
9647 detecting RGB vs BGR issues. You should see a red, green and blue
9648 stripe from top to bottom.
9650 The @code{smptebars} source generates a color bars pattern, based on
9651 the SMPTE Engineering Guideline EG 1-1990.
9653 The @code{smptehdbars} source generates a color bars pattern, based on
9654 the SMPTE RP 219-2002.
9656 The @code{testsrc} source generates a test video pattern, showing a
9657 color pattern, a scrolling gradient and a timestamp. This is mainly
9658 intended for testing purposes.
9660 The sources accept the following parameters:
9665 Specify the color of the source, only available in the @code{color}
9666 source. For the syntax of this option, check the "Color" section in the
9667 ffmpeg-utils manual.
9670 Specify the level of the Hald CLUT, only available in the @code{haldclutsrc}
9671 source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N}
9672 pixels to be used as identity matrix for 3D lookup tables. Each component is
9673 coded on a @code{1/(N*N)} scale.
9676 Specify the size of the sourced video. For the syntax of this option, check the
9677 "Video size" section in the ffmpeg-utils manual. The default value is
9680 This option is not available with the @code{haldclutsrc} filter.
9683 Specify the frame rate of the sourced video, as the number of frames
9684 generated per second. It has to be a string in the format
9685 @var{frame_rate_num}/@var{frame_rate_den}, an integer number, a floating point
9686 number or a valid video frame rate abbreviation. The default value is
9690 Set the sample aspect ratio of the sourced video.
9693 Set the video duration of the sourced video. The accepted syntax is:
9695 [-]HH[:MM[:SS[.m...]]]
9698 Also see the the @code{av_parse_time()} function.
9700 If not specified, or the expressed duration is negative, the video is
9701 supposed to be generated forever.
9704 Set the number of decimals to show in the timestamp, only available in the
9705 @code{testsrc} source.
9707 The displayed timestamp value will correspond to the original
9708 timestamp value multiplied by the power of 10 of the specified
9709 value. Default value is 0.
9712 For example the following:
9714 testsrc=duration=5.3:size=qcif:rate=10
9717 will generate a video with a duration of 5.3 seconds, with size
9718 176x144 and a frame rate of 10 frames per second.
9720 The following graph description will generate a red source
9721 with an opacity of 0.2, with size "qcif" and a frame rate of 10
9724 color=c=red@@0.2:s=qcif:r=10
9727 If the input content is to be ignored, @code{nullsrc} can be used. The
9728 following command generates noise in the luminance plane by employing
9729 the @code{geq} filter:
9731 nullsrc=s=256x256, geq=random(1)*255:128:128
9734 @subsection Commands
9736 The @code{color} source supports the following commands:
9740 Set the color of the created image. Accepts the same syntax of the
9741 corresponding @option{color} option.
9744 @c man end VIDEO SOURCES
9746 @chapter Video Sinks
9747 @c man begin VIDEO SINKS
9749 Below is a description of the currently available video sinks.
9753 Buffer video frames, and make them available to the end of the filter
9756 This sink is mainly intended for programmatic use, in particular
9757 through the interface defined in @file{libavfilter/buffersink.h}
9758 or the options system.
9760 It accepts a pointer to an AVBufferSinkContext structure, which
9761 defines the incoming buffers' formats, to be passed as the opaque
9762 parameter to @code{avfilter_init_filter} for initialization.
9766 Null video sink: do absolutely nothing with the input video. It is
9767 mainly useful as a template and for use in analysis / debugging
9770 @c man end VIDEO SINKS
9772 @chapter Multimedia Filters
9773 @c man begin MULTIMEDIA FILTERS
9775 Below is a description of the currently available multimedia filters.
9777 @section avectorscope
9779 Convert input audio to a video output, representing the audio vector
9782 The filter is used to measure the difference between channels of stereo
9783 audio stream. A monoaural signal, consisting of identical left and right
9784 signal, results in straight vertical line. Any stereo separation is visible
9785 as a deviation from this line, creating a Lissajous figure.
9786 If the straight (or deviation from it) but horizontal line appears this
9787 indicates that the left and right channels are out of phase.
9789 The filter accepts the following options:
9793 Set the vectorscope mode.
9795 Available values are:
9798 Lissajous rotated by 45 degrees.
9801 Same as above but not rotated.
9804 Default value is @samp{lissajous}.
9807 Set the video size for the output. For the syntax of this option, check the "Video size"
9808 section in the ffmpeg-utils manual. Default value is @code{400x400}.
9811 Set the output frame rate. Default value is @code{25}.
9816 Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}.
9817 Allowed range is @code{[0, 255]}.
9822 Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}.
9823 Allowed range is @code{[0, 255]}.
9826 Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}.
9829 @subsection Examples
9833 Complete example using @command{ffplay}:
9835 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
9836 [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'
9842 Concatenate audio and video streams, joining them together one after the
9845 The filter works on segments of synchronized video and audio streams. All
9846 segments must have the same number of streams of each type, and that will
9847 also be the number of streams at output.
9849 The filter accepts the following options:
9854 Set the number of segments. Default is 2.
9857 Set the number of output video streams, that is also the number of video
9858 streams in each segment. Default is 1.
9861 Set the number of output audio streams, that is also the number of audio
9862 streams in each segment. Default is 0.
9865 Activate unsafe mode: do not fail if segments have a different format.
9869 The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
9870 @var{a} audio outputs.
9872 There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first
9873 segment, in the same order as the outputs, then the inputs for the second
9876 Related streams do not always have exactly the same duration, for various
9877 reasons including codec frame size or sloppy authoring. For that reason,
9878 related synchronized streams (e.g. a video and its audio track) should be
9879 concatenated at once. The concat filter will use the duration of the longest
9880 stream in each segment (except the last one), and if necessary pad shorter
9881 audio streams with silence.
9883 For this filter to work correctly, all segments must start at timestamp 0.
9885 All corresponding streams must have the same parameters in all segments; the
9886 filtering system will automatically select a common pixel format for video
9887 streams, and a common sample format, sample rate and channel layout for
9888 audio streams, but other settings, such as resolution, must be converted
9889 explicitly by the user.
9891 Different frame rates are acceptable but will result in variable frame rate
9892 at output; be sure to configure the output file to handle it.
9894 @subsection Examples
9898 Concatenate an opening, an episode and an ending, all in bilingual version
9899 (video in stream 0, audio in streams 1 and 2):
9901 ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
9902 '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
9903 concat=n=3:v=1:a=2 [v] [a1] [a2]' \
9904 -map '[v]' -map '[a1]' -map '[a2]' output.mkv
9908 Concatenate two parts, handling audio and video separately, using the
9909 (a)movie sources, and adjusting the resolution:
9911 movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
9912 movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
9913 [v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
9915 Note that a desync will happen at the stitch if the audio and video streams
9916 do not have exactly the same duration in the first file.
9922 EBU R128 scanner filter. This filter takes an audio stream as input and outputs
9923 it unchanged. By default, it logs a message at a frequency of 10Hz with the
9924 Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
9925 Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
9927 The filter also has a video output (see the @var{video} option) with a real
9928 time graph to observe the loudness evolution. The graphic contains the logged
9929 message mentioned above, so it is not printed anymore when this option is set,
9930 unless the verbose logging is set. The main graphing area contains the
9931 short-term loudness (3 seconds of analysis), and the gauge on the right is for
9932 the momentary loudness (400 milliseconds).
9934 More information about the Loudness Recommendation EBU R128 on
9935 @url{http://tech.ebu.ch/loudness}.
9937 The filter accepts the following options:
9942 Activate the video output. The audio stream is passed unchanged whether this
9943 option is set or no. The video stream will be the first output stream if
9944 activated. Default is @code{0}.
9947 Set the video size. This option is for video only. For the syntax of this
9948 option, check the "Video size" section in the ffmpeg-utils manual. Default
9949 and minimum resolution is @code{640x480}.
9952 Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
9953 @code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
9954 other integer value between this range is allowed.
9957 Set metadata injection. If set to @code{1}, the audio input will be segmented
9958 into 100ms output frames, each of them containing various loudness information
9959 in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}.
9961 Default is @code{0}.
9964 Force the frame logging level.
9966 Available values are:
9969 information logging level
9971 verbose logging level
9974 By default, the logging level is set to @var{info}. If the @option{video} or
9975 the @option{metadata} options are set, it switches to @var{verbose}.
9980 Available modes can be cumulated (the option is a @code{flag} type). Possible
9984 Disable any peak mode (default).
9986 Enable sample-peak mode.
9988 Simple peak mode looking for the higher sample value. It logs a message
9989 for sample-peak (identified by @code{SPK}).
9991 Enable true-peak mode.
9993 If enabled, the peak lookup is done on an over-sampled version of the input
9994 stream for better peak accuracy. It logs a message for true-peak.
9995 (identified by @code{TPK}) and true-peak per frame (identified by @code{FTPK}).
9996 This mode requires a build with @code{libswresample}.
10001 @subsection Examples
10005 Real-time graph using @command{ffplay}, with a EBU scale meter +18:
10007 ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"
10011 Run an analysis with @command{ffmpeg}:
10013 ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
10017 @section interleave, ainterleave
10019 Temporally interleave frames from several inputs.
10021 @code{interleave} works with video inputs, @code{ainterleave} with audio.
10023 These filters read frames from several inputs and send the oldest
10024 queued frame to the output.
10026 Input streams must have a well defined, monotonically increasing frame
10029 In order to submit one frame to output, these filters need to enqueue
10030 at least one frame for each input, so they cannot work in case one
10031 input is not yet terminated and will not receive incoming frames.
10033 For example consider the case when one input is a @code{select} filter
10034 which always drop input frames. The @code{interleave} filter will keep
10035 reading from that input, but it will never be able to send new frames
10036 to output until the input will send an end-of-stream signal.
10038 Also, depending on inputs synchronization, the filters will drop
10039 frames in case one input receives more frames than the other ones, and
10040 the queue is already filled.
10042 These filters accept the following options:
10046 Set the number of different inputs, it is 2 by default.
10049 @subsection Examples
10053 Interleave frames belonging to different streams using @command{ffmpeg}:
10055 ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi
10059 Add flickering blur effect:
10061 select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave
10065 @section perms, aperms
10067 Set read/write permissions for the output frames.
10069 These filters are mainly aimed at developers to test direct path in the
10070 following filter in the filtergraph.
10072 The filters accept the following options:
10076 Select the permissions mode.
10078 It accepts the following values:
10081 Do nothing. This is the default.
10083 Set all the output frames read-only.
10085 Set all the output frames directly writable.
10087 Make the frame read-only if writable, and writable if read-only.
10089 Set each output frame read-only or writable randomly.
10093 Set the seed for the @var{random} mode, must be an integer included between
10094 @code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to
10095 @code{-1}, the filter will try to use a good random seed on a best effort
10099 Note: in case of auto-inserted filter between the permission filter and the
10100 following one, the permission might not be received as expected in that
10101 following filter. Inserting a @ref{format} or @ref{aformat} filter before the
10102 perms/aperms filter can avoid this problem.
10104 @section select, aselect
10106 Select frames to pass in output.
10108 This filter accepts the following options:
10113 Set expression, which is evaluated for each input frame.
10115 If the expression is evaluated to zero, the frame is discarded.
10117 If the evaluation result is negative or NaN, the frame is sent to the
10118 first output; otherwise it is sent to the output with index
10119 @code{ceil(val)-1}, assuming that the input index starts from 0.
10121 For example a value of @code{1.2} corresponds to the output with index
10122 @code{ceil(1.2)-1 = 2-1 = 1}, that is the second output.
10125 Set the number of outputs. The output to which to send the selected
10126 frame is based on the result of the evaluation. Default value is 1.
10129 The expression can contain the following constants:
10133 The (sequential) number of the filtered frame, starting from 0.
10136 The (sequential) number of the selected frame, starting from 0.
10138 @item prev_selected_n
10139 The sequential number of the last selected frame. It's NAN if undefined.
10142 The timebase of the input timestamps.
10145 The PTS (Presentation TimeStamp) of the filtered video frame,
10146 expressed in @var{TB} units. It's NAN if undefined.
10149 The PTS of the filtered video frame,
10150 expressed in seconds. It's NAN if undefined.
10153 The PTS of the previously filtered video frame. It's NAN if undefined.
10155 @item prev_selected_pts
10156 The PTS of the last previously filtered video frame. It's NAN if undefined.
10158 @item prev_selected_t
10159 The PTS of the last previously selected video frame. It's NAN if undefined.
10162 The PTS of the first video frame in the video. It's NAN if undefined.
10165 The time of the first video frame in the video. It's NAN if undefined.
10167 @item pict_type @emph{(video only)}
10168 The type of the filtered frame. It can assume one of the following
10180 @item interlace_type @emph{(video only)}
10181 The frame interlace type. It can assume one of the following values:
10184 The frame is progressive (not interlaced).
10186 The frame is top-field-first.
10188 The frame is bottom-field-first.
10191 @item consumed_sample_n @emph{(audio only)}
10192 the number of selected samples before the current frame
10194 @item samples_n @emph{(audio only)}
10195 the number of samples in the current frame
10197 @item sample_rate @emph{(audio only)}
10198 the input sample rate
10201 This is 1 if the filtered frame is a key-frame, 0 otherwise.
10204 the position in the file of the filtered frame, -1 if the information
10205 is not available (e.g. for synthetic video)
10207 @item scene @emph{(video only)}
10208 value between 0 and 1 to indicate a new scene; a low value reflects a low
10209 probability for the current frame to introduce a new scene, while a higher
10210 value means the current frame is more likely to be one (see the example below)
10214 The default value of the select expression is "1".
10216 @subsection Examples
10220 Select all frames in input:
10225 The example above is the same as:
10237 Select only I-frames:
10239 select='eq(pict_type\,I)'
10243 Select one frame every 100:
10245 select='not(mod(n\,100))'
10249 Select only frames contained in the 10-20 time interval:
10251 select=between(t\,10\,20)
10255 Select only I frames contained in the 10-20 time interval:
10257 select=between(t\,10\,20)*eq(pict_type\,I)
10261 Select frames with a minimum distance of 10 seconds:
10263 select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
10267 Use aselect to select only audio frames with samples number > 100:
10269 aselect='gt(samples_n\,100)'
10273 Create a mosaic of the first scenes:
10275 ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
10278 Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
10282 Send even and odd frames to separate outputs, and compose them:
10284 select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h
10288 @section sendcmd, asendcmd
10290 Send commands to filters in the filtergraph.
10292 These filters read commands to be sent to other filters in the
10295 @code{sendcmd} must be inserted between two video filters,
10296 @code{asendcmd} must be inserted between two audio filters, but apart
10297 from that they act the same way.
10299 The specification of commands can be provided in the filter arguments
10300 with the @var{commands} option, or in a file specified by the
10301 @var{filename} option.
10303 These filters accept the following options:
10306 Set the commands to be read and sent to the other filters.
10308 Set the filename of the commands to be read and sent to the other
10312 @subsection Commands syntax
10314 A commands description consists of a sequence of interval
10315 specifications, comprising a list of commands to be executed when a
10316 particular event related to that interval occurs. The occurring event
10317 is typically the current frame time entering or leaving a given time
10320 An interval is specified by the following syntax:
10322 @var{START}[-@var{END}] @var{COMMANDS};
10325 The time interval is specified by the @var{START} and @var{END} times.
10326 @var{END} is optional and defaults to the maximum time.
10328 The current frame time is considered within the specified interval if
10329 it is included in the interval [@var{START}, @var{END}), that is when
10330 the time is greater or equal to @var{START} and is lesser than
10333 @var{COMMANDS} consists of a sequence of one or more command
10334 specifications, separated by ",", relating to that interval. The
10335 syntax of a command specification is given by:
10337 [@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
10340 @var{FLAGS} is optional and specifies the type of events relating to
10341 the time interval which enable sending the specified command, and must
10342 be a non-null sequence of identifier flags separated by "+" or "|" and
10343 enclosed between "[" and "]".
10345 The following flags are recognized:
10348 The command is sent when the current frame timestamp enters the
10349 specified interval. In other words, the command is sent when the
10350 previous frame timestamp was not in the given interval, and the
10354 The command is sent when the current frame timestamp leaves the
10355 specified interval. In other words, the command is sent when the
10356 previous frame timestamp was in the given interval, and the
10360 If @var{FLAGS} is not specified, a default value of @code{[enter]} is
10363 @var{TARGET} specifies the target of the command, usually the name of
10364 the filter class or a specific filter instance name.
10366 @var{COMMAND} specifies the name of the command for the target filter.
10368 @var{ARG} is optional and specifies the optional list of argument for
10369 the given @var{COMMAND}.
10371 Between one interval specification and another, whitespaces, or
10372 sequences of characters starting with @code{#} until the end of line,
10373 are ignored and can be used to annotate comments.
10375 A simplified BNF description of the commands specification syntax
10378 @var{COMMAND_FLAG} ::= "enter" | "leave"
10379 @var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
10380 @var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
10381 @var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
10382 @var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
10383 @var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
10386 @subsection Examples
10390 Specify audio tempo change at second 4:
10392 asendcmd=c='4.0 atempo tempo 1.5',atempo
10396 Specify a list of drawtext and hue commands in a file.
10398 # show text in the interval 5-10
10399 5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
10400 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
10402 # desaturate the image in the interval 15-20
10403 15.0-20.0 [enter] hue s 0,
10404 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
10406 [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
10408 # apply an exponential saturation fade-out effect, starting from time 25
10409 25 [enter] hue s exp(25-t)
10412 A filtergraph allowing to read and process the above command list
10413 stored in a file @file{test.cmd}, can be specified with:
10415 sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
10420 @section setpts, asetpts
10422 Change the PTS (presentation timestamp) of the input frames.
10424 @code{setpts} works on video frames, @code{asetpts} on audio frames.
10426 This filter accepts the following options:
10431 The expression which is evaluated for each frame to construct its timestamp.
10435 The expression is evaluated through the eval API and can contain the following
10440 frame rate, only defined for constant frame-rate video
10443 The presentation timestamp in input
10446 The count of the input frame for video or the number of consumed samples,
10447 not including the current frame for audio, starting from 0.
10449 @item NB_CONSUMED_SAMPLES
10450 The number of consumed samples, not including the current frame (only
10453 @item NB_SAMPLES, S
10454 The number of samples in the current frame (only audio)
10456 @item SAMPLE_RATE, SR
10457 The audio sample rate.
10460 The PTS of the first frame.
10463 the time in seconds of the first frame
10466 State whether the current frame is interlaced.
10469 the time in seconds of the current frame
10472 original position in the file of the frame, or undefined if undefined
10473 for the current frame
10476 The previous input PTS.
10479 previous input time in seconds
10482 The previous output PTS.
10485 previous output time in seconds
10488 The wallclock (RTC) time in microseconds.. This is deprecated, use time(0)
10492 The wallclock (RTC) time at the start of the movie in microseconds.
10495 The timebase of the input timestamps.
10499 @subsection Examples
10503 Start counting PTS from zero
10505 setpts=PTS-STARTPTS
10509 Apply fast motion effect:
10515 Apply slow motion effect:
10521 Set fixed rate of 25 frames per second:
10527 Set fixed rate 25 fps with some jitter:
10529 setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
10533 Apply an offset of 10 seconds to the input PTS:
10539 Generate timestamps from a "live source" and rebase onto the current timebase:
10541 setpts='(RTCTIME - RTCSTART) / (TB * 1000000)'
10545 Generate timestamps by counting samples:
10552 @section settb, asettb
10554 Set the timebase to use for the output frames timestamps.
10555 It is mainly useful for testing timebase configuration.
10557 It accepts the following parameters:
10562 The expression which is evaluated into the output timebase.
10566 The value for @option{tb} is an arithmetic expression representing a
10567 rational. The expression can contain the constants "AVTB" (the default
10568 timebase), "intb" (the input timebase) and "sr" (the sample rate,
10569 audio only). Default value is "intb".
10571 @subsection Examples
10575 Set the timebase to 1/25:
10581 Set the timebase to 1/10:
10587 Set the timebase to 1001/1000:
10593 Set the timebase to 2*intb:
10599 Set the default timebase value:
10606 Convert input audio to a video output representing
10607 frequency spectrum logarithmically (using constant Q transform with
10608 Brown-Puckette algorithm), with musical tone scale, from E0 to D#10 (10 octaves).
10610 The filter accepts the following options:
10614 Specify transform volume (multiplier) expression. The expression can contain
10617 @item frequency, freq, f
10618 the frequency where transform is evaluated
10619 @item timeclamp, tc
10620 value of timeclamp option
10624 @item a_weighting(f)
10625 A-weighting of equal loudness
10626 @item b_weighting(f)
10627 B-weighting of equal loudness
10628 @item c_weighting(f)
10629 C-weighting of equal loudness
10631 Default value is @code{16}.
10634 Specify transform length expression. The expression can contain variables:
10636 @item frequency, freq, f
10637 the frequency where transform is evaluated
10638 @item timeclamp, tc
10639 value of timeclamp option
10641 Default value is @code{384/f*tc/(384/f+tc)}.
10644 Specify the transform timeclamp. At low frequency, there is trade-off between
10645 accuracy in time domain and frequency domain. If timeclamp is lower,
10646 event in time domain is represented more accurately (such as fast bass drum),
10647 otherwise event in frequency domain is represented more accurately
10648 (such as bass guitar). Acceptable value is [0.1, 1.0]. Default value is @code{0.17}.
10651 Specify the transform coeffclamp. If coeffclamp is lower, transform is
10652 more accurate, otherwise transform is faster. Acceptable value is [0.1, 10.0].
10653 Default value is @code{1.0}.
10656 Specify gamma. Lower gamma makes the spectrum more contrast, higher gamma
10657 makes the spectrum having more range. Acceptable value is [1.0, 7.0].
10658 Default value is @code{3.0}.
10661 Specify font file for use with freetype. If not specified, use embedded font.
10664 If set to 1 (the default), the video size is 1920x1080 (full HD),
10665 if set to 0, the video size is 960x540. Use this option to make CPU usage lower.
10668 Specify video fps. Default value is @code{25}.
10671 Specify number of transform per frame, so there are fps*count transforms
10672 per second. Note that audio data rate must be divisible by fps*count.
10673 Default value is @code{6}.
10677 @subsection Examples
10681 Playing audio while showing the spectrum:
10683 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt [out0]'
10687 Same as above, but with frame rate 30 fps:
10689 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fps=30:count=5 [out0]'
10693 Playing at 960x540 and lower CPU usage:
10695 ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a] showcqt=fullhd=0:count=3 [out0]'
10699 A1 and its harmonics: A1, A2, (near)E3, A3:
10701 ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
10702 asplit[a][out1]; [a] showcqt [out0]'
10706 Same as above, but with more accuracy in frequency domain (and slower):
10708 ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
10709 asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'
10713 B-weighting of equal loudness
10715 volume=16*b_weighting(f)
10721 tlength=100/f*tc/(100/f+tc)
10726 @section showspectrum
10728 Convert input audio to a video output, representing the audio frequency
10731 The filter accepts the following options:
10735 Specify the video size for the output. For the syntax of this option, check
10736 the "Video size" section in the ffmpeg-utils manual. Default value is
10740 Specify how the spectrum should slide along the window.
10742 It accepts the following values:
10745 the samples start again on the left when they reach the right
10747 the samples scroll from right to left
10749 frames are only produced when the samples reach the right
10752 Default value is @code{replace}.
10755 Specify display mode.
10757 It accepts the following values:
10760 all channels are displayed in the same row
10762 all channels are displayed in separate rows
10765 Default value is @samp{combined}.
10768 Specify display color mode.
10770 It accepts the following values:
10773 each channel is displayed in a separate color
10775 each channel is is displayed using the same color scheme
10778 Default value is @samp{channel}.
10781 Specify scale used for calculating intensity color values.
10783 It accepts the following values:
10788 square root, default
10795 Default value is @samp{sqrt}.
10798 Set saturation modifier for displayed colors. Negative values provide
10799 alternative color scheme. @code{0} is no saturation at all.
10800 Saturation must be in [-10.0, 10.0] range.
10801 Default value is @code{1}.
10804 Set window function.
10806 It accepts the following values:
10809 No samples pre-processing (do not expect this to be faster)
10818 Default value is @code{hann}.
10821 The usage is very similar to the showwaves filter; see the examples in that
10824 @subsection Examples
10828 Large window with logarithmic color scaling:
10830 showspectrum=s=1280x480:scale=log
10834 Complete example for a colored and sliding spectrum per channel using @command{ffplay}:
10836 ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
10837 [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'
10843 Convert input audio to a video output, representing the samples waves.
10845 The filter accepts the following options:
10849 Specify the video size for the output. For the syntax of this option, check
10850 the "Video size" section in the ffmpeg-utils manual. Default value
10856 Available values are:
10859 Draw a point for each sample.
10862 Draw a vertical line for each sample.
10865 Draw a point for each sample and a line between them.
10868 Draw a centered vertical line for each sample.
10871 Default value is @code{point}.
10874 Set the number of samples which are printed on the same column. A
10875 larger value will decrease the frame rate. Must be a positive
10876 integer. This option can be set only if the value for @var{rate}
10877 is not explicitly specified.
10880 Set the (approximate) output frame rate. This is done by setting the
10881 option @var{n}. Default value is "25".
10883 @item split_channels
10884 Set if channels should be drawn separately or overlap. Default value is 0.
10888 @subsection Examples
10892 Output the input file audio and the corresponding video representation
10895 amovie=a.mp3,asplit[out0],showwaves[out1]
10899 Create a synthetic signal and show it with showwaves, forcing a
10900 frame rate of 30 frames per second:
10902 aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
10906 @section split, asplit
10908 Split input into several identical outputs.
10910 @code{asplit} works with audio input, @code{split} with video.
10912 The filter accepts a single parameter which specifies the number of outputs. If
10913 unspecified, it defaults to 2.
10915 @subsection Examples
10919 Create two separate outputs from the same input:
10921 [in] split [out0][out1]
10925 To create 3 or more outputs, you need to specify the number of
10928 [in] asplit=3 [out0][out1][out2]
10932 Create two separate outputs from the same input, one cropped and
10935 [in] split [splitout1][splitout2];
10936 [splitout1] crop=100:100:0:0 [cropout];
10937 [splitout2] pad=200:200:100:100 [padout];
10941 Create 5 copies of the input audio with @command{ffmpeg}:
10943 ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
10949 Receive commands sent through a libzmq client, and forward them to
10950 filters in the filtergraph.
10952 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
10953 must be inserted between two video filters, @code{azmq} between two
10956 To enable these filters you need to install the libzmq library and
10957 headers and configure FFmpeg with @code{--enable-libzmq}.
10959 For more information about libzmq see:
10960 @url{http://www.zeromq.org/}
10962 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
10963 receives messages sent through a network interface defined by the
10964 @option{bind_address} option.
10966 The received message must be in the form:
10968 @var{TARGET} @var{COMMAND} [@var{ARG}]
10971 @var{TARGET} specifies the target of the command, usually the name of
10972 the filter class or a specific filter instance name.
10974 @var{COMMAND} specifies the name of the command for the target filter.
10976 @var{ARG} is optional and specifies the optional argument list for the
10977 given @var{COMMAND}.
10979 Upon reception, the message is processed and the corresponding command
10980 is injected into the filtergraph. Depending on the result, the filter
10981 will send a reply to the client, adopting the format:
10983 @var{ERROR_CODE} @var{ERROR_REASON}
10987 @var{MESSAGE} is optional.
10989 @subsection Examples
10991 Look at @file{tools/zmqsend} for an example of a zmq client which can
10992 be used to send commands processed by these filters.
10994 Consider the following filtergraph generated by @command{ffplay}
10996 ffplay -dumpgraph 1 -f lavfi "
10997 color=s=100x100:c=red [l];
10998 color=s=100x100:c=blue [r];
10999 nullsrc=s=200x100, zmq [bg];
11000 [bg][l] overlay [bg+l];
11001 [bg+l][r] overlay=x=100 "
11004 To change the color of the left side of the video, the following
11005 command can be used:
11007 echo Parsed_color_0 c yellow | tools/zmqsend
11010 To change the right side:
11012 echo Parsed_color_1 c pink | tools/zmqsend
11015 @c man end MULTIMEDIA FILTERS
11017 @chapter Multimedia Sources
11018 @c man begin MULTIMEDIA SOURCES
11020 Below is a description of the currently available multimedia sources.
11024 This is the same as @ref{movie} source, except it selects an audio
11030 Read audio and/or video stream(s) from a movie container.
11032 It accepts the following parameters:
11036 The name of the resource to read (not necessarily a file; it can also be a
11037 device or a stream accessed through some protocol).
11039 @item format_name, f
11040 Specifies the format assumed for the movie to read, and can be either
11041 the name of a container or an input device. If not specified, the
11042 format is guessed from @var{movie_name} or by probing.
11044 @item seek_point, sp
11045 Specifies the seek point in seconds. The frames will be output
11046 starting from this seek point. The parameter is evaluated with
11047 @code{av_strtod}, so the numerical value may be suffixed by an IS
11048 postfix. The default value is "0".
11051 Specifies the streams to read. Several streams can be specified,
11052 separated by "+". The source will then have as many outputs, in the
11053 same order. The syntax is explained in the ``Stream specifiers''
11054 section in the ffmpeg manual. Two special names, "dv" and "da" specify
11055 respectively the default (best suited) video and audio stream. Default
11056 is "dv", or "da" if the filter is called as "amovie".
11058 @item stream_index, si
11059 Specifies the index of the video stream to read. If the value is -1,
11060 the most suitable video stream will be automatically selected. The default
11061 value is "-1". Deprecated. If the filter is called "amovie", it will select
11062 audio instead of video.
11065 Specifies how many times to read the stream in sequence.
11066 If the value is less than 1, the stream will be read again and again.
11067 Default value is "1".
11069 Note that when the movie is looped the source timestamps are not
11070 changed, so it will generate non monotonically increasing timestamps.
11073 It allows overlaying a second video on top of the main input of
11074 a filtergraph, as shown in this graph:
11076 input -----------> deltapts0 --> overlay --> output
11079 movie --> scale--> deltapts1 -------+
11081 @subsection Examples
11085 Skip 3.2 seconds from the start of the AVI file in.avi, and overlay it
11086 on top of the input labelled "in":
11088 movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over];
11089 [in] setpts=PTS-STARTPTS [main];
11090 [main][over] overlay=16:16 [out]
11094 Read from a video4linux2 device, and overlay it on top of the input
11097 movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
11098 [in] setpts=PTS-STARTPTS [main];
11099 [main][over] overlay=16:16 [out]
11103 Read the first video stream and the audio stream with id 0x81 from
11104 dvd.vob; the video is connected to the pad named "video" and the audio is
11105 connected to the pad named "audio":
11107 movie=dvd.vob:s=v:0+#0x81 [video] [audio]
11111 @c man end MULTIMEDIA SOURCES